Delay Tolerant Networking (DTN) is a promising technology that aims to provide efficient communication
between devices in a network with no guaranteed continuous connectivity. Most existing routing schemes
for DTNs exploit the advantage of message replication to achieve high message delivery rate. However,
these schemes commonly suffer from large communication overhead due to the lack of efficient mechanisms
to control message replication. In this paper we give a brief survey on routing protocols designed for
DTNs, and evaluate the performance of several representative routing protocols including Epidemic, Spray
and Wait, PRoPHET, and 3R through extensive trace-driven simulations. Another objective of this work is
to evaluate the security strength of different routing schemes under common DTN attacks such as the black
hole attack. The results and analysis presented in this paper can provide useful guidance on the design and
selection of routing protocols for given delay-tolerant applications.
Delay Tolerant Network (DTN) is a promising technology which aims to provide efficient
communication between devices in a network with no guaranteed continuous connectivity. Most
of the existing routing schemes for DTNs achieve message delivery through message replication
and forwarding. However, due to the lack of contemporaneous end-to-end communication path,
designing routing protocols that can achieve high delivery rate with low communication
overhead is a challenging problem. Some routing protocols appear with high similarity, but
their performance are significantly different. In this paper, we evaluate several popular routing
protocols in DTNs, including Epidemic, Spray and Wait, PRoPHET, and 3R through extensive
trace-driven simulations. The objective is to evaluate the performance of different routing
schemes using different data traces and investigate the optimal configuration setting for each
routing scheme. This paper provides important guidances on the design and selection of routing
protocols for given delay tolerant networks.
Multicasting in Delay Tolerant Networks: Implementation and Performance AnalysisNagendra Posani
Delay Tolerant Networks(DTN) are a class of emerg- ing networks which experience intermittent connectivity and lack end-to-end paths due to absence of well-defined infrastructure. In this paper we explore the nuances of multicasting in DTNs. Multicasting enables efficient distribution of messages to a group of users, a paradigm that can be applicable in the context of DTNs. While multicasting in internet and ad-hoc networks has been studied extensively, realizing the same in DTNs is non- trivial given that many factors have to be considered. This paper, presents an implementation of multicast routing for various protocols in DTNs using ONE simulator. It also provides the analysis and performance results for the various protocols studies against the different movement models.
This presentation covers some of the routing protocols for Delay Tolerant Networks (DTN) along with the overview of the Opportunistic Networking Environment which can be used for performance evaluation/comparison of/among these DTN protocols.
P.S. This presentation is for educational purpose only. It is not meant for any commercialization at all.
This document summarizes and compares existing routing protocols for delay tolerant networks. It presents routing protocols such as first contact, direct delivery, PROPHET, spray and wait, and epidemic routing. It also proposes a new dynamic spray and wait protocol that considers the quality of nodes based on their activity level. Simulation results show that the proposed algorithm that considers message size, number of copies, and time to live performs better than the traditional drop front approach in terms of delivery probability, buffer time average, overhead ratio, packets dropped, and hop count average.
PRoPHET uses its delivery predictability of node encounters and transitivity to forward bundles to its neighbor node. Regardless of their distance, it faces delivery dilemmas in a source node and drawbacks of low delivery ratio and high delay in case two or more neighbor nodes carry equal delivery predictability. To solve such consequences, we propose a Distance and Probabilistic Routing Protocol using History of Encounters and Transitivity (DPRoPHET) with the use of cross layer implementation for distance value retrieval. Our simulation results show that, by adding distance metric to the existing delivery predictability vector, DPRoPHET outperforms PRoPHET.
Advisedly delayed packet attack on tcp based mobile ad-hoc networkseSAT Journals
Abstract Efficient routing in mobile ad-hoc networks (MANETs) is a challenging task due to its varying physical channel characteristics, dynamic topology and un-centralized communication. Furthermore, multihop routing is required when the source-destination pairs are not in each other’s communication range. Due to the above challenges these networks are vulnerable to various types of attacks on various layers of the TCP/IP protocol stack. In this thesis, we implement and analyze an attack called advisedly delay packet attack on ad-hoc on-demand distance vector (AODV) routing protocol. The advisedly delay packet attack is an attack that effects the TCP-based as well as UDP-based data transmissions but in this thesis we will also see how it exploits the TCP congestion control mechanism to decrease the throughput of the network. In this attack, the attacker exploit the period of retransmission time out (RTO) of the sender and attack in such a way so the sender is always transmitting in the slow start phase. Keywords- MANETs; Multimedia Streaming; Routing protocols; QoS; Topology; Node Mobility; Network Scalability
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Performance evaluation of rapid and spray and-wait dtn routing protocols unde...eSAT Journals
Abstract DTN (Delay Tolerant Network) is a new concept in the field of wireless networks. It enables communication in challenged environment where traditional network fails. Unlike other ad hoc wireless network it does not demand for end to end node connectivity. DTN is based on store carry and forward principle. This mechanism is implemented using bundle protocol. DTN nodes have capabilities such as radio interface, movement, persistent storage, message routing and energy consumption .Here a node might accumulate a message in its buffer and carry it for limited time, waiting till a suitable forwarding opportunity is acquired. Multiple message duplication into the network is done to increase delivery probability. The main objective of DTN Routing is to build a powerful network between various nodes (mobile devices, planetary vehicles etc) so that good delivery probability and less delay are obtained. This unique mechanism poses a security challenge. A sophisticated attack observed is black hole attack in which malicious intermediate node are present in network that can provide attacked forged metrics to another node. The aim of this work is to simulate and analyze routing protocol of DTN when nodes enter in environment with black hole attack. The work has been carried out with ONE (opportunistic network environment) simulator. The performance of routing protocols (RAPID and Spray and Wait) are tested for different number of attacking nodes. The analysis indicates there is decrease in delivery probability, hop count average and buffer time average. But latency average first increases and then start decreasing. The overhead ratio increases using Spray and Wait Protocol but with RAPID protocol, it decreases with increasing black hole attacking nodes. Index Terms: DTN, ONE, etc.
Delay Tolerant Network (DTN) is a promising technology which aims to provide efficient
communication between devices in a network with no guaranteed continuous connectivity. Most
of the existing routing schemes for DTNs achieve message delivery through message replication
and forwarding. However, due to the lack of contemporaneous end-to-end communication path,
designing routing protocols that can achieve high delivery rate with low communication
overhead is a challenging problem. Some routing protocols appear with high similarity, but
their performance are significantly different. In this paper, we evaluate several popular routing
protocols in DTNs, including Epidemic, Spray and Wait, PRoPHET, and 3R through extensive
trace-driven simulations. The objective is to evaluate the performance of different routing
schemes using different data traces and investigate the optimal configuration setting for each
routing scheme. This paper provides important guidances on the design and selection of routing
protocols for given delay tolerant networks.
Multicasting in Delay Tolerant Networks: Implementation and Performance AnalysisNagendra Posani
Delay Tolerant Networks(DTN) are a class of emerg- ing networks which experience intermittent connectivity and lack end-to-end paths due to absence of well-defined infrastructure. In this paper we explore the nuances of multicasting in DTNs. Multicasting enables efficient distribution of messages to a group of users, a paradigm that can be applicable in the context of DTNs. While multicasting in internet and ad-hoc networks has been studied extensively, realizing the same in DTNs is non- trivial given that many factors have to be considered. This paper, presents an implementation of multicast routing for various protocols in DTNs using ONE simulator. It also provides the analysis and performance results for the various protocols studies against the different movement models.
This presentation covers some of the routing protocols for Delay Tolerant Networks (DTN) along with the overview of the Opportunistic Networking Environment which can be used for performance evaluation/comparison of/among these DTN protocols.
P.S. This presentation is for educational purpose only. It is not meant for any commercialization at all.
This document summarizes and compares existing routing protocols for delay tolerant networks. It presents routing protocols such as first contact, direct delivery, PROPHET, spray and wait, and epidemic routing. It also proposes a new dynamic spray and wait protocol that considers the quality of nodes based on their activity level. Simulation results show that the proposed algorithm that considers message size, number of copies, and time to live performs better than the traditional drop front approach in terms of delivery probability, buffer time average, overhead ratio, packets dropped, and hop count average.
PRoPHET uses its delivery predictability of node encounters and transitivity to forward bundles to its neighbor node. Regardless of their distance, it faces delivery dilemmas in a source node and drawbacks of low delivery ratio and high delay in case two or more neighbor nodes carry equal delivery predictability. To solve such consequences, we propose a Distance and Probabilistic Routing Protocol using History of Encounters and Transitivity (DPRoPHET) with the use of cross layer implementation for distance value retrieval. Our simulation results show that, by adding distance metric to the existing delivery predictability vector, DPRoPHET outperforms PRoPHET.
Advisedly delayed packet attack on tcp based mobile ad-hoc networkseSAT Journals
Abstract Efficient routing in mobile ad-hoc networks (MANETs) is a challenging task due to its varying physical channel characteristics, dynamic topology and un-centralized communication. Furthermore, multihop routing is required when the source-destination pairs are not in each other’s communication range. Due to the above challenges these networks are vulnerable to various types of attacks on various layers of the TCP/IP protocol stack. In this thesis, we implement and analyze an attack called advisedly delay packet attack on ad-hoc on-demand distance vector (AODV) routing protocol. The advisedly delay packet attack is an attack that effects the TCP-based as well as UDP-based data transmissions but in this thesis we will also see how it exploits the TCP congestion control mechanism to decrease the throughput of the network. In this attack, the attacker exploit the period of retransmission time out (RTO) of the sender and attack in such a way so the sender is always transmitting in the slow start phase. Keywords- MANETs; Multimedia Streaming; Routing protocols; QoS; Topology; Node Mobility; Network Scalability
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Performance evaluation of rapid and spray and-wait dtn routing protocols unde...eSAT Journals
Abstract DTN (Delay Tolerant Network) is a new concept in the field of wireless networks. It enables communication in challenged environment where traditional network fails. Unlike other ad hoc wireless network it does not demand for end to end node connectivity. DTN is based on store carry and forward principle. This mechanism is implemented using bundle protocol. DTN nodes have capabilities such as radio interface, movement, persistent storage, message routing and energy consumption .Here a node might accumulate a message in its buffer and carry it for limited time, waiting till a suitable forwarding opportunity is acquired. Multiple message duplication into the network is done to increase delivery probability. The main objective of DTN Routing is to build a powerful network between various nodes (mobile devices, planetary vehicles etc) so that good delivery probability and less delay are obtained. This unique mechanism poses a security challenge. A sophisticated attack observed is black hole attack in which malicious intermediate node are present in network that can provide attacked forged metrics to another node. The aim of this work is to simulate and analyze routing protocol of DTN when nodes enter in environment with black hole attack. The work has been carried out with ONE (opportunistic network environment) simulator. The performance of routing protocols (RAPID and Spray and Wait) are tested for different number of attacking nodes. The analysis indicates there is decrease in delivery probability, hop count average and buffer time average. But latency average first increases and then start decreasing. The overhead ratio increases using Spray and Wait Protocol but with RAPID protocol, it decreases with increasing black hole attacking nodes. Index Terms: DTN, ONE, etc.
This document evaluates different spray-based routing approaches for delay tolerant networks (DTNs). It summarizes the spray and wait routing algorithm and some variants proposed to improve it. The document performs simulations to compare the delivery ratio, overhead ratio, and average latency of the basic spray and wait approaches to variants that incorporate utility metrics or acknowledgements. The results show that a composite method that includes delivery predictability and acknowledgements outperforms the other variants in terms of delivery ratio and average latency.
Performance evaluation of rapid and spray and-wait dtn routing protocols unde...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Enhance the Throughput of Wireless Network Using Multicast RoutingIOSR Journals
Wireless Mesh Network is designed static or limited mobility environment .In multicast routing for
wireless mesh networks has focused on metrics that estimate link quality to maximize throughput
andtoprovide secure communication. Nodes must collaborate in order to compute the path metric and
forward data.Node identify the novel attacks against high- throughput multicast protocols in wireless
mesh network.. The attacks exploit the local estimation and global aggregation of the metric to allow
attackers to attract a large amount of traffic These attacks are very effective b a s e d on high
throughput metrics. The aggressive path selection is a double-edged sword: It is maximizes throughput,
it also increases attack effectiveness. so Rate guard mechanism will be used.Rate guard mechanism
means combines Measurement-based detection and accusation-based reaction techniques.The attacks
and the defense using ODMRP, a representative multicast protocol for wireless mesh networks, and
SPP, an adaptation of the well-known ETX unicast metric to the multicast setting
This document discusses routing strategies in delay tolerant networks (DTNs) using wireless sensor network (WSN) nodes for localization applications. It first provides background on WSNs and DTNs, and then reviews common DTN routing protocols like epidemic routing, PROPHET, spray and wait, and MaxProp. The aim of the dissertation is to propose a new routing protocol for DTNs using WSN nodes where GPS is unavailable. It discusses using a hybrid of knowledge-based and additional node-based routing. The document outlines simulating the proposed filtered flooding protocol in NS-2 to evaluate delivery ratio and delay for a mining activity scenario. Results show delivery ratio is high for small networks but decreases with more nodes, while delay is
To Lie or To Comply: Defending against Flood Attacks in Disruption Tolerant N...Vamsi IV
Disruption Tolerant Networks (DTNs) utilize the mobility of nodes and the opportunistic contacts among nodes for data communications. Due to the limitation in network resources such as contact opportunity and buffer space, DTNs are vulnerable to flood attacks in which attackers send as many packets or packet replicas as possible to the network, in order to deplete or overuse the limited network resources. In this paper, we employ rate limiting to defend against flood attacks in DTNs, such that each node has a limit over the number of packets that it can generate in each time interval and a limit over the number of replicas that it can generate for each packet. We propose a distributed scheme to detect if a node has violated its rate limits. To address the challenge that it is difficult to count all the packets or replicas sent by a node due to lack of communication infrastructure, our detection adopts claim-carry-and check: each node itself counts the number of packets or replicas that it has sent and claims the count to other nodes; the receiving nodes carry the claims when they move, and cross-check if their carried claims are inconsistent when they contact. The claim structure uses the pigeonhole principle to guarantee that an attacker will make inconsistent claims which may lead to detection. We provide rigorous analysis on the probability of detection, and evaluate the effectiveness and efficiency of our scheme with extensive trace driven simulations.
Delay Tolerant Networks(DTN) are a class of emerg- ing networks which experience intermittent connectivity and lack end-to-end paths due to absence of well-defined infrastructure. In this paper we explore the nuances of multicasting in DTNs. Multicasting enables efficient distribution of messages to a group of users, a paradigm that can be applicable in the context of DTNs. While multicasting in internet and ad-hoc networks has been studied extensively, realizing the same in DTNs is non- trivial given that many factors have to be considered. This paper, presents an implementation of multicast routing for various protocols in DTNs using ONE simulator. It also provides the analysis and performance results for the various protocols studies against the different movement models.
Performance investigation of re shuffling packet attack on transport layer pr...eSAT Journals
Abstract Over the past decade, the wireless world has experienced significant developments. The emergence and proliferation of radio frequency networking products, wireless devices like handheld, wearable and portable computers, Personal Digital Assistants (PDA)s, cellular phone have given rise to a kind of wireless revolution. A mobile ad hoc network is much more assailable to attacks than a wired network due to its limited physical security, high mobility and lack of centralized administration. In this paper, we present and analyze the effects of re-shuffling attack on TCP based mobile ad-hoc networks named as Packet Re-Shuffling. In the packet reshuffling attack the malicious node will reorder the packets in its FIFO buffer before forwarding them towards their destination. Due to the out of order delivery the retransmission time out of the packet is triggered and the source TCP and UDP has to retransmit the packet. In this way it also stops the TCP to perform the congestion avoidance technique. A malicious node will always participate in route setup operations. For example, if source routing is employed, malicious nodes always relay Route Request packets in order to have as many routes as possible flowing through themselves; if distance vector routing is employed, malicious nodes will also obey all control-plane protocol specifications. However, once a route is established, attacking nodes will thwart the end-to-end throughput of the flow via above mentioned attacks. The effect of the proposed attack is analyzed with the simulation results generated using the trial version of the simulator known as Exata Cyber 2.0. The simulation results are given in terms of metrics such as data flow throughput, Packet Retransmission, average end-to-end delay and packet delivery ratio. In this paper, we are giving The study on UDP and TCP. Keywords: MANETs; Multimedia Streaming; Routing protocols; QoS; Topology; Node Mobility; Network Scalability;
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Delay tolerant network routing protocol a comprehensive survey with hybrid...eSAT Journals
Abstract
Delay –disruption Tolerant networks are sparse wireless network which is recently being used by the existing /current network for the purpose to connect devices or the underdeveloped area of the world that works in challenging environment. In DTN there majority of time does not exist the total path from source to target which is leads to the difficulty of how to route the packet in such environment. A communications network which is accomplished of storing packets temporarily in intermediate nodes, until the time an end-to-end route is re-established or regenerated is known as a delay tolerant networks. Routing in such network is very difficult and for that different routing protocols are developed. In this Survey paper we discuss about various routing Strategy and at the end compared the different routing protocol with their various performance metrics.
Keywords: Delay tolerant networks (DTNs), Erasure coding, Replication, Routing.
Hexagonal based Clustering for Reducing Rebroadcasts in Mobile Ad Hoc NetworksIJTET Journal
Abstract— In mobile ad hoc networks multihop routing is performed in order to communicate the packets from the source to destination. The nodes within these networks are dynamic due which frequent path change occurs which can cause frequent link breakages and induces route discoveries. These route discoveries can introduce overhead in terms of contention, collision and rebroadcasts which are non-negligible. Here, the paper discusses a hexagonal based clustering for reducing rebroadcasts thus maximizing the lifetime of the networks and providing coverage area thus reducing the end – end delays.
Distributed Denial-of-Service (DDoS) attacks are a critical threat to the Internet. A distributed denial-of-service attack is one in which a multitude of compromised systems attack a single target, thereby causing denial of service for users of the targeted system. The flood of incoming messages to the target system essentially forces it to shut down, thereby denying service to the system to legitimate users. The proposed system suggests a mechanism based on entropy variations between normal and DDoS attack traffic. Entropy is an information theoretic concept, which is a measure of randomness. The proposed method employs entropy variation to measure changes of randomness of flows. The implementation of the proposed method brings no modifications on current routing software.
A black-hole attack in the Mobile Ad-hoc NETwork (MANET) is an attack occurs due to malicious nodes,
which attracts the data packets by falsely advertising a fresh route to the destination. In this paper, we
present a clustering approach in Ad-hoc On-demand Distance Vector (AODV) routing protocol for the
detection and prevention of black-hole attack in MANETs. In this approach every member of the cluster will
ping once to the cluster head, to detect the peculiar difference between the number of data packets received
and forwarded by the node. If anomalousness is perceived, all the nodes will obscure the malicious nodes
from the network.
Iaetsd a secured based information sharing scheme viaIaetsd Iaetsd
The document proposes a secured based information sharing scheme for delay tolerant networks using smartphones. It suggests using a discover-predict-deliver (DPD) approach for efficient content sharing. Specifically, DPD employs machine learning to identify meaningful locations from a user's mobility patterns using a hidden Markov model. Simulation results show DPD can discover and deliver 87% of content within two hours when only 30% of nodes initially have the content. The document also aims to reduce energy consumption using asymmetric multicore processors and efficient sensor scheduling with probabilistic optimal multi-parameter duty cycles.
One of the most popular areas of research is wireless communication. Mobile Ad Hoc network (MANET) is a network with wireless mobile nodes, infrastructure less and self organizing. With its wireless and distributed nature it is exposed to several security threats. One of the threats in MANET is the wormhole attack. In this attack a pair of attacker forms a virtual link thereby recording and replaying the wireless transmission. This paper presents types of wormhole attack and also includes different technique for detecting wormhole attack in MANET..
A MANET is a continuously self-configuring, infrastructure-less type network, which consists of number of mobile nodes
with wireless network interfaces. In order to make communication among nodes, the nodes demoniacally establish paths among
neighbouring nodes. Security in mobile adhoc network is a big challenge because many nodes perform many kinds of misbehaviour.
In this paper, the main focus is on collaborative attacks in MANET using CBDS approach. CBDS is a approach which consolidate
asset of proactive and reactive defense method in reverse tracing. In reverse tracing method we compare performance of CBDS
approach with DSR and AOMDV routing protocols.
TRIDNT: THE TRUST-BASED ROUTING PROTOCOL WITH CONTROLLED DEGREE OF NODE SELFI...IJNSA Journal
In Mobile ad-hoc network, nodes must cooperate to achieve the routing purposes. Node misbehaviour due to selfish or malicious intention could significantly degrade the performance of MANET because most existing routing protocols in MANET are aiming at finding most efficiency path. In this paper, we propose a Two node-disjoint Routes protocol for Isolating Dropper Node in MANET (TRIDNT) to deal with misbehaviour in MANET. TRIDNT allows some degree of selfishness to give an incentive to the selfish nodes to declare itself to its neighbours, which reduce the misbehaving nodes searching time. In TRIDNT two node-disjoint routes between the source and destination are selected based on their trust values. We use both DLL-ACK and end-to-end TCP-ACK to monitor the behaviour of routing path nodes: if a malicious behaviour is detected then the path searching tool starts to identify the malicious nodes and isolate them. Finally by using a mathematical analysis we find that our proposed protocol reduces the searching time of malicious nodes comparing to the route expected life time, and avoids the isolated misbehaving node from sharing in all future routes, which improve the overall network throughput.
DDoS Attack and Defense Scheme in Wireless Ad hoc NetworksIJNSA Journal
The wireless ad hoc networks are highly vulnerable to distributed denial of service(DDoS) attacks because of its unique characteristics such as open network architecture, shared wireless medium and stringent resource constraints. These attacks throttle the tcp throughput heavily and reduce the quality of service(QoS) to end systems gradually rather than refusing the clients from the services completely. In this paper, we discussed the DDoS attacks and proposed a defense scheme to improve the performance of the ad hoc networks. Our proposed defense mechanism uses the medium access control (MAC) layer information to detect the attackers. The status values from MAC layer that can be used for detection are Frequency of receiving RTS/CTS packets, Frequency of sensing a busy channel and the number of RTS/DATA retransmissions. Once the attackers are identified, all the packets from those nodes will be blocked. The network resources are made available to the legitimate users. We perform the simulation with Network Simulator NS2 and we proved that our proposed system improves the network performance.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Energy Saving DSR and Probabilistic Rebroadcast Mechanism are used to Increas...IJTET Journal
Abstract- MANETs are infrastructure less and can be set up anytime anywhere. Due to high mobility of nodes in mobile ad hoc networks (MANETs), there exist frequent link breakages which lead to frequent path failures and route discoveries. The overhead of a route discovery cannot be neglected. In a route discovery, broadcasting is a fundamental and effective data broadcasting mechanism, where a mobile node blindly rebroadcasts the first received route request packets unless it has a route to the destination, and thus it causes the broadcast storm problem and without consider the nodes energy level of route selection it leads to reduce the network lifetime. In this paper proposed to focus is on a two mechanism ESDSR and Neighbor coverage based Probabilistic rebroadcast to overcome those problems. A Energy Saving Dynamic Source Routing in MANETs (ESDSR) which will efficiently utilize the battery power consideration in the route selection time of mobile nodes in such a way that the network will get more life time and Neighbor coverage based Probabilistic rebroadcast mechanism, which can significantly decrease the number of retransmissions so as to reduce the routing overhead, and can also improve the routing performance. The simulation was carried out using the NS-2 network simulator.
Review of Flooding Attack Detection in AODV Protocol for Mobile Ad-hoc Networkijsrd.com
Ad Hoc Networks are extremely vulnerable to attacks due to their dynamically changing topology, absence of conventional security infrastructures, vulnerability of nodes and channels and open medium of communication. Denial of Service (DoS) and Distributed DoS (DDoS) attacks are two of the most harmful threats to the network functionality. The Prevention methods like authentication and cryptography techniques alone are not able to provide the security to these types of networks. Therefore, efficient intrusion detection must be deployed to facilitate the identification and isolation of attacks. Major attacks on Mobile Ad hoc networks are flooding, selective forwarding, sinkhole, wormhole etc. We have presented various intrusion detection techniques in MANET. Then we have proposed a method to detect flooding attack in MANET.
Performance of the IEEE 802.15.4a UWB System using Two Pulse Shaping Techniqu...ijwmn
In Cognitive radio (CR) applications Ultra-wideband (UWB) impulse radio (IR) signals can be designed
such as they can co-exist with licensed primary users. The pulse shape should be adjusted such that the
power spectral characteristics not only meet the Federal Communications Commission (FCC) constrains,
but also mitigate multiple narrow-band interference at the locations of existing primary users. In this
paper, the Parks-McClellan (PM) Algorithm and the Eigen Value Decomposition (EVD) approach for
UWB impulse radio waveform shaping are considered. The power spectral density (PSD) and the bit-errorrate
(BER) performance of the two methods are compared in the presence of single and double narrowband
interference (NBI). The interference rejection capabilities of the two methods are evaluated and
compared for different interference and additive noise levels. In particular, the simulations consider the
coexistence of practical IEEE 802.15.4a UWB systems with both IEEE 802.11 wireless LAN systems
operating at 5.2 GHz and radio location services operating at 8.5 GHz.
An efficient model for reducing soft blocking probability in wireless cellula...ijwmn
One of the research challenges in cellular networks is the design of an efficient model that can reduce call
blocking probability and improve the quality of service (QoS) provided to mobile users. Blocking occurs
when a new call cannot be admitted into the network due to channel unavailability caused by limited
capacity or when an ongoing call cannot be continued as it moves from one base station to another due to
mobility of the user. The proposed model computes the steady state probability and resource occupancy
distribution, traffic distribution, intra-cell and inter-cell interferences from mobile users. Previously
proposed models are reviewed through which the present model is built for use in emerging wireless
networks so as to obtain improved QoS performance. The developed model is validated through simulations
in MATLAB and its equations implemented using Java Programming Language. The results obtained
indicate reduced call blocking probability below threshold.
This document evaluates different spray-based routing approaches for delay tolerant networks (DTNs). It summarizes the spray and wait routing algorithm and some variants proposed to improve it. The document performs simulations to compare the delivery ratio, overhead ratio, and average latency of the basic spray and wait approaches to variants that incorporate utility metrics or acknowledgements. The results show that a composite method that includes delivery predictability and acknowledgements outperforms the other variants in terms of delivery ratio and average latency.
Performance evaluation of rapid and spray and-wait dtn routing protocols unde...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Enhance the Throughput of Wireless Network Using Multicast RoutingIOSR Journals
Wireless Mesh Network is designed static or limited mobility environment .In multicast routing for
wireless mesh networks has focused on metrics that estimate link quality to maximize throughput
andtoprovide secure communication. Nodes must collaborate in order to compute the path metric and
forward data.Node identify the novel attacks against high- throughput multicast protocols in wireless
mesh network.. The attacks exploit the local estimation and global aggregation of the metric to allow
attackers to attract a large amount of traffic These attacks are very effective b a s e d on high
throughput metrics. The aggressive path selection is a double-edged sword: It is maximizes throughput,
it also increases attack effectiveness. so Rate guard mechanism will be used.Rate guard mechanism
means combines Measurement-based detection and accusation-based reaction techniques.The attacks
and the defense using ODMRP, a representative multicast protocol for wireless mesh networks, and
SPP, an adaptation of the well-known ETX unicast metric to the multicast setting
This document discusses routing strategies in delay tolerant networks (DTNs) using wireless sensor network (WSN) nodes for localization applications. It first provides background on WSNs and DTNs, and then reviews common DTN routing protocols like epidemic routing, PROPHET, spray and wait, and MaxProp. The aim of the dissertation is to propose a new routing protocol for DTNs using WSN nodes where GPS is unavailable. It discusses using a hybrid of knowledge-based and additional node-based routing. The document outlines simulating the proposed filtered flooding protocol in NS-2 to evaluate delivery ratio and delay for a mining activity scenario. Results show delivery ratio is high for small networks but decreases with more nodes, while delay is
To Lie or To Comply: Defending against Flood Attacks in Disruption Tolerant N...Vamsi IV
Disruption Tolerant Networks (DTNs) utilize the mobility of nodes and the opportunistic contacts among nodes for data communications. Due to the limitation in network resources such as contact opportunity and buffer space, DTNs are vulnerable to flood attacks in which attackers send as many packets or packet replicas as possible to the network, in order to deplete or overuse the limited network resources. In this paper, we employ rate limiting to defend against flood attacks in DTNs, such that each node has a limit over the number of packets that it can generate in each time interval and a limit over the number of replicas that it can generate for each packet. We propose a distributed scheme to detect if a node has violated its rate limits. To address the challenge that it is difficult to count all the packets or replicas sent by a node due to lack of communication infrastructure, our detection adopts claim-carry-and check: each node itself counts the number of packets or replicas that it has sent and claims the count to other nodes; the receiving nodes carry the claims when they move, and cross-check if their carried claims are inconsistent when they contact. The claim structure uses the pigeonhole principle to guarantee that an attacker will make inconsistent claims which may lead to detection. We provide rigorous analysis on the probability of detection, and evaluate the effectiveness and efficiency of our scheme with extensive trace driven simulations.
Delay Tolerant Networks(DTN) are a class of emerg- ing networks which experience intermittent connectivity and lack end-to-end paths due to absence of well-defined infrastructure. In this paper we explore the nuances of multicasting in DTNs. Multicasting enables efficient distribution of messages to a group of users, a paradigm that can be applicable in the context of DTNs. While multicasting in internet and ad-hoc networks has been studied extensively, realizing the same in DTNs is non- trivial given that many factors have to be considered. This paper, presents an implementation of multicast routing for various protocols in DTNs using ONE simulator. It also provides the analysis and performance results for the various protocols studies against the different movement models.
Performance investigation of re shuffling packet attack on transport layer pr...eSAT Journals
Abstract Over the past decade, the wireless world has experienced significant developments. The emergence and proliferation of radio frequency networking products, wireless devices like handheld, wearable and portable computers, Personal Digital Assistants (PDA)s, cellular phone have given rise to a kind of wireless revolution. A mobile ad hoc network is much more assailable to attacks than a wired network due to its limited physical security, high mobility and lack of centralized administration. In this paper, we present and analyze the effects of re-shuffling attack on TCP based mobile ad-hoc networks named as Packet Re-Shuffling. In the packet reshuffling attack the malicious node will reorder the packets in its FIFO buffer before forwarding them towards their destination. Due to the out of order delivery the retransmission time out of the packet is triggered and the source TCP and UDP has to retransmit the packet. In this way it also stops the TCP to perform the congestion avoidance technique. A malicious node will always participate in route setup operations. For example, if source routing is employed, malicious nodes always relay Route Request packets in order to have as many routes as possible flowing through themselves; if distance vector routing is employed, malicious nodes will also obey all control-plane protocol specifications. However, once a route is established, attacking nodes will thwart the end-to-end throughput of the flow via above mentioned attacks. The effect of the proposed attack is analyzed with the simulation results generated using the trial version of the simulator known as Exata Cyber 2.0. The simulation results are given in terms of metrics such as data flow throughput, Packet Retransmission, average end-to-end delay and packet delivery ratio. In this paper, we are giving The study on UDP and TCP. Keywords: MANETs; Multimedia Streaming; Routing protocols; QoS; Topology; Node Mobility; Network Scalability;
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Delay tolerant network routing protocol a comprehensive survey with hybrid...eSAT Journals
Abstract
Delay –disruption Tolerant networks are sparse wireless network which is recently being used by the existing /current network for the purpose to connect devices or the underdeveloped area of the world that works in challenging environment. In DTN there majority of time does not exist the total path from source to target which is leads to the difficulty of how to route the packet in such environment. A communications network which is accomplished of storing packets temporarily in intermediate nodes, until the time an end-to-end route is re-established or regenerated is known as a delay tolerant networks. Routing in such network is very difficult and for that different routing protocols are developed. In this Survey paper we discuss about various routing Strategy and at the end compared the different routing protocol with their various performance metrics.
Keywords: Delay tolerant networks (DTNs), Erasure coding, Replication, Routing.
Hexagonal based Clustering for Reducing Rebroadcasts in Mobile Ad Hoc NetworksIJTET Journal
Abstract— In mobile ad hoc networks multihop routing is performed in order to communicate the packets from the source to destination. The nodes within these networks are dynamic due which frequent path change occurs which can cause frequent link breakages and induces route discoveries. These route discoveries can introduce overhead in terms of contention, collision and rebroadcasts which are non-negligible. Here, the paper discusses a hexagonal based clustering for reducing rebroadcasts thus maximizing the lifetime of the networks and providing coverage area thus reducing the end – end delays.
Distributed Denial-of-Service (DDoS) attacks are a critical threat to the Internet. A distributed denial-of-service attack is one in which a multitude of compromised systems attack a single target, thereby causing denial of service for users of the targeted system. The flood of incoming messages to the target system essentially forces it to shut down, thereby denying service to the system to legitimate users. The proposed system suggests a mechanism based on entropy variations between normal and DDoS attack traffic. Entropy is an information theoretic concept, which is a measure of randomness. The proposed method employs entropy variation to measure changes of randomness of flows. The implementation of the proposed method brings no modifications on current routing software.
A black-hole attack in the Mobile Ad-hoc NETwork (MANET) is an attack occurs due to malicious nodes,
which attracts the data packets by falsely advertising a fresh route to the destination. In this paper, we
present a clustering approach in Ad-hoc On-demand Distance Vector (AODV) routing protocol for the
detection and prevention of black-hole attack in MANETs. In this approach every member of the cluster will
ping once to the cluster head, to detect the peculiar difference between the number of data packets received
and forwarded by the node. If anomalousness is perceived, all the nodes will obscure the malicious nodes
from the network.
Iaetsd a secured based information sharing scheme viaIaetsd Iaetsd
The document proposes a secured based information sharing scheme for delay tolerant networks using smartphones. It suggests using a discover-predict-deliver (DPD) approach for efficient content sharing. Specifically, DPD employs machine learning to identify meaningful locations from a user's mobility patterns using a hidden Markov model. Simulation results show DPD can discover and deliver 87% of content within two hours when only 30% of nodes initially have the content. The document also aims to reduce energy consumption using asymmetric multicore processors and efficient sensor scheduling with probabilistic optimal multi-parameter duty cycles.
One of the most popular areas of research is wireless communication. Mobile Ad Hoc network (MANET) is a network with wireless mobile nodes, infrastructure less and self organizing. With its wireless and distributed nature it is exposed to several security threats. One of the threats in MANET is the wormhole attack. In this attack a pair of attacker forms a virtual link thereby recording and replaying the wireless transmission. This paper presents types of wormhole attack and also includes different technique for detecting wormhole attack in MANET..
A MANET is a continuously self-configuring, infrastructure-less type network, which consists of number of mobile nodes
with wireless network interfaces. In order to make communication among nodes, the nodes demoniacally establish paths among
neighbouring nodes. Security in mobile adhoc network is a big challenge because many nodes perform many kinds of misbehaviour.
In this paper, the main focus is on collaborative attacks in MANET using CBDS approach. CBDS is a approach which consolidate
asset of proactive and reactive defense method in reverse tracing. In reverse tracing method we compare performance of CBDS
approach with DSR and AOMDV routing protocols.
TRIDNT: THE TRUST-BASED ROUTING PROTOCOL WITH CONTROLLED DEGREE OF NODE SELFI...IJNSA Journal
In Mobile ad-hoc network, nodes must cooperate to achieve the routing purposes. Node misbehaviour due to selfish or malicious intention could significantly degrade the performance of MANET because most existing routing protocols in MANET are aiming at finding most efficiency path. In this paper, we propose a Two node-disjoint Routes protocol for Isolating Dropper Node in MANET (TRIDNT) to deal with misbehaviour in MANET. TRIDNT allows some degree of selfishness to give an incentive to the selfish nodes to declare itself to its neighbours, which reduce the misbehaving nodes searching time. In TRIDNT two node-disjoint routes between the source and destination are selected based on their trust values. We use both DLL-ACK and end-to-end TCP-ACK to monitor the behaviour of routing path nodes: if a malicious behaviour is detected then the path searching tool starts to identify the malicious nodes and isolate them. Finally by using a mathematical analysis we find that our proposed protocol reduces the searching time of malicious nodes comparing to the route expected life time, and avoids the isolated misbehaving node from sharing in all future routes, which improve the overall network throughput.
DDoS Attack and Defense Scheme in Wireless Ad hoc NetworksIJNSA Journal
The wireless ad hoc networks are highly vulnerable to distributed denial of service(DDoS) attacks because of its unique characteristics such as open network architecture, shared wireless medium and stringent resource constraints. These attacks throttle the tcp throughput heavily and reduce the quality of service(QoS) to end systems gradually rather than refusing the clients from the services completely. In this paper, we discussed the DDoS attacks and proposed a defense scheme to improve the performance of the ad hoc networks. Our proposed defense mechanism uses the medium access control (MAC) layer information to detect the attackers. The status values from MAC layer that can be used for detection are Frequency of receiving RTS/CTS packets, Frequency of sensing a busy channel and the number of RTS/DATA retransmissions. Once the attackers are identified, all the packets from those nodes will be blocked. The network resources are made available to the legitimate users. We perform the simulation with Network Simulator NS2 and we proved that our proposed system improves the network performance.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Energy Saving DSR and Probabilistic Rebroadcast Mechanism are used to Increas...IJTET Journal
Abstract- MANETs are infrastructure less and can be set up anytime anywhere. Due to high mobility of nodes in mobile ad hoc networks (MANETs), there exist frequent link breakages which lead to frequent path failures and route discoveries. The overhead of a route discovery cannot be neglected. In a route discovery, broadcasting is a fundamental and effective data broadcasting mechanism, where a mobile node blindly rebroadcasts the first received route request packets unless it has a route to the destination, and thus it causes the broadcast storm problem and without consider the nodes energy level of route selection it leads to reduce the network lifetime. In this paper proposed to focus is on a two mechanism ESDSR and Neighbor coverage based Probabilistic rebroadcast to overcome those problems. A Energy Saving Dynamic Source Routing in MANETs (ESDSR) which will efficiently utilize the battery power consideration in the route selection time of mobile nodes in such a way that the network will get more life time and Neighbor coverage based Probabilistic rebroadcast mechanism, which can significantly decrease the number of retransmissions so as to reduce the routing overhead, and can also improve the routing performance. The simulation was carried out using the NS-2 network simulator.
Review of Flooding Attack Detection in AODV Protocol for Mobile Ad-hoc Networkijsrd.com
Ad Hoc Networks are extremely vulnerable to attacks due to their dynamically changing topology, absence of conventional security infrastructures, vulnerability of nodes and channels and open medium of communication. Denial of Service (DoS) and Distributed DoS (DDoS) attacks are two of the most harmful threats to the network functionality. The Prevention methods like authentication and cryptography techniques alone are not able to provide the security to these types of networks. Therefore, efficient intrusion detection must be deployed to facilitate the identification and isolation of attacks. Major attacks on Mobile Ad hoc networks are flooding, selective forwarding, sinkhole, wormhole etc. We have presented various intrusion detection techniques in MANET. Then we have proposed a method to detect flooding attack in MANET.
Performance of the IEEE 802.15.4a UWB System using Two Pulse Shaping Techniqu...ijwmn
In Cognitive radio (CR) applications Ultra-wideband (UWB) impulse radio (IR) signals can be designed
such as they can co-exist with licensed primary users. The pulse shape should be adjusted such that the
power spectral characteristics not only meet the Federal Communications Commission (FCC) constrains,
but also mitigate multiple narrow-band interference at the locations of existing primary users. In this
paper, the Parks-McClellan (PM) Algorithm and the Eigen Value Decomposition (EVD) approach for
UWB impulse radio waveform shaping are considered. The power spectral density (PSD) and the bit-errorrate
(BER) performance of the two methods are compared in the presence of single and double narrowband
interference (NBI). The interference rejection capabilities of the two methods are evaluated and
compared for different interference and additive noise levels. In particular, the simulations consider the
coexistence of practical IEEE 802.15.4a UWB systems with both IEEE 802.11 wireless LAN systems
operating at 5.2 GHz and radio location services operating at 8.5 GHz.
An efficient model for reducing soft blocking probability in wireless cellula...ijwmn
One of the research challenges in cellular networks is the design of an efficient model that can reduce call
blocking probability and improve the quality of service (QoS) provided to mobile users. Blocking occurs
when a new call cannot be admitted into the network due to channel unavailability caused by limited
capacity or when an ongoing call cannot be continued as it moves from one base station to another due to
mobility of the user. The proposed model computes the steady state probability and resource occupancy
distribution, traffic distribution, intra-cell and inter-cell interferences from mobile users. Previously
proposed models are reviewed through which the present model is built for use in emerging wireless
networks so as to obtain improved QoS performance. The developed model is validated through simulations
in MATLAB and its equations implemented using Java Programming Language. The results obtained
indicate reduced call blocking probability below threshold.
Performance evaluation of different spectrum sensing techniques for realistic...ijwmn
In this paper, the performance assessment of five different detection techniques from spectrum sensing
perspective in cognitive radio networks is proposed and implemented using the realistic implementation
oriented model (R-model) with signal processing operations. The performance assessment of the different
sensing techniques in the existence of unknown or imprecisely known impulsive noise levels is done by
considering the signal detection in cognitive radio networks under a non-parametric multisensory detection
scenario. The examination focuses on performance comparison of basic spectrum sensing mechanisms as,
energy detection (ED) and cyclostationary feature detection (CSFD) along with the eigenvalue-based
detection methods namely, Maximum-minimum eigenvalue detection (MMED), Roy’s largest Root Test
(RLRT) which requires knowledge of the noise variance and Generalized Likelihood Ratio Test (GLRT)
which can be implemented as a test of the largest eigenvalues vs. Maximum-likelihood estimates a noise
variance. From simulation results it is observed that the detection performance of the GLRT method is
better than the other techniques in realistic implementation oriented model.
Wireless sensor nodes are usually deployed in not easily accessible places to provide solution to a wide
range of application such as environmental, medical and structural monitoring. They are spatially
distributed and as a result are usually powered from batteries. Due to the limitation in providing power
with batteries, which must be manually replaced when they are depleted, and location constraints in
wireless sensor network causes a major setback on performance and lifetime of WSNs. This difficulty in
battery replacement and cost led to a growing interest in energy harvesting. The current practice in energy
harvesting for sensor networks is based on practical and simulation approach. The evaluation and
validation of the WSN systems is mostly done using simulation and practical implementation. Simulation is
widely used especially for its great advantage in evaluating network systems. Its disadvantages such as the
long time taken to simulate and not being economical as it implements data without proper analysis of all
that is involved ,wasting useful resources cannot be ignored. In most times, the energy scavenged is directly
wired to the sensor nodes. We, therefore, argue that simulation – based and practical implementation of
WSN energy harvesting system should be further strengthened through mathematical analysis and design
procedures. In this work, we designed and modeled the energy harvesting system for wireless sensor nodes
based on the input and output parameters of the energy sources and sensor nodes. We also introduced the
use of supercapacitor as buffer and intermittent source for the sensor node. The model was further tested in
a Matlab environment, and found to yield a very good approach for system design.
This document summarizes the design and performance evaluation of a two-unit Yagi-Uda antenna array for UHF satellite communication. Simulations were conducted using 4NEC2 software to optimize the design for a gain of 18.6 dBi at 437.025 MHz. Field tests validated the antenna array achieved high gain and front-to-back ratio while maintaining low standing wave ratio across the UHF band. The two-unit circularly polarized crossed Yagi array design successfully improved communication link margins for small cube satellites operating with stringent power budgets.
EFFECTS OF FILTERS ON THE PERFORMANCE OF DVB-T RECEIVERijwmn
Digital Video Broadcasting-Terrestrial (DVB-T) is an international standard for digital television
services. Orthogonal Frequency Division Multiplexing (OFDM) is the core of this technology. OFDM
based system like DVB-T can handle multipath fading and hence it can minimize Inter Symbol
Interference (ISI). DVB-T has some limitations too namely large dynamic range of the signals and
sensitivity to frequency error. In order to overcome these limitations DVB-T receivers should be optimally
designed. In this paper we address the issues related to optimal DVB-T receiver design. There of several
signal processing units in a DVB-T receiver. A low-pass filter is one of them. In this paper, we consider
some classic filters namely Butterworth, Chebyshev, and elliptic in the DVB-T receiver. The effects of
different filters on the performances of DVB-T receiver have been investigated and compared in this
paper under AWGN channel condition
SELECTION OF SPECTRUM SENSING METHOD TO ENHANCE QOS IN COGNITIVE RADIO NETWORKSijwmn
The massively increasing number of wireless communication devices has led to considerable growths in
radio traffic density, resulting in a predictable shortage of the available spectrum. To address this potential
shortage, the Cognitive Radio (CR) technology offers promising solutions that aim to improve the spectrum
utilization. The operation of CR relies on detecting the so-called spectrum holes, i.e., the frequency bands
when they are unoccupied by their licensed operators. The unlicensed users are then allowed to
communicate using these spectrum holes. Consequently, the performance of CR is highly dependent on the
employed spectrum sensing methods. Several sensing methods are already available or literarily proposed.
However, no individual method can accommodate all possible CR operation scenarios. Hence, it is fair to
ascertain that the performance of a CR device can be improved if it is capable of supporting several
sensing methods. Then it should be able to effectively select the most suitable method. In this paper, several
spectrum sensing methods are compared and analyzed, aiming to identify their advantages and
shortcomings in different CR operating conditions. Furthermore, it identifies the factors that need to be
considered while selecting a proper sensing method from the catalog of available methods.
PERFORMANCE IMPROVEMENT OF PAPR REDUCTION FOR OFDM SIGNAL IN LTE SYSTEMijwmn
This document discusses performance improvement of peak-to-average power ratio (PAPR) reduction for orthogonal frequency division multiplexing (OFDM) signals in long-term evolution (LTE) systems. It proposes an improved amplitude clipping and filtering method for PAPR reduction that shows significant improvement over existing methods, with a slight increase in bit error rate. The document provides background on OFDM, PAPR issues in OFDM, and motivations for reducing PAPR such as improving power amplifier efficiency.
DYNAMIC OPTIMIZATION OF OVERLAP-AND-ADD LENGTH OVER MIMO MBOFDM SYSTEM BASED ...ijwmn
An important role performed by Zero Padding (ZP) in multi-band OFDM (MB-OFDM) System. This role
show for low-complexity in résistance against multipath interference by reducing inter-carrier interference
(ICI) and eliminating the inter-symbol interference (ISI) Also, zero-padded suffix can be used to eliminate
ripples in the power spectral density in order to conform to FCC requirements. At the receiver of MB-OFDM system needs to use of a technique called as overlap-and-add (OLA). Which maintain the circular convolution property and take the multipath energy of the channel.In this paper, we proposed a method of performing overlap-and-add length for zero padded suffixes. Then,we studied the effect of this method, dynamic optimization of overlap-and-add (OLA) equalization, on the performance of MIMO MBOFDM system on Bit Error Rate (BER) with AWGN channel and SalehValenzuela (S-V) Multipath channel Model.In the dynamic optimization OLA, the Length of ZP depends on length of channel impulse response (CIR).
These measures, based on SNR, insert the ZP according to the measurement.Dynamic optimization of length of ZP improves the Performance of MIMO MBOFDM system. In fact wedeveloped a technique to select the length of ZP as function of SNR and CIR estimate. In our simulation
this technique improve to 0.6 dB at BER=10-2 with a multipath channels CM4
A novel energy efficient routing algorithm for wireless sensor networks using...ijwmn
There are numerous applications for wireless sensor networks which are inevitable now a day in our daily
life. Majority of such applications which use wireless sensor networks will be in areas where the direct
human intervention is impossible. So the limited energy available in such sensors is a threat for prolonging
the life of the entire network. The need of energy efficiency in wireless sensor networks is a hot research
topic in which lot of new strategies for improvement in energy efficiency has been sought after. As
communication process consumes more energy, an energy efficient routing strategy can probably reduce
the energy consumption to a great extend. This paper gives an overview of the different routing techniques
in which mobile sinks are used to facilitate the routing process which can effectively reduce the energy use.
A new routing strategy with mobile sinks and a static sink is proposed and is compared based on the
matrices life time and average energy of the nodes with the existing Shortest Hop path (SH) algorithm. The
simulation results shows the proposed algorithm is more energy efficient than the existing one.
The delivering of both good quality of service (QoS) and Grade of Service (GoS) in any competitive mobile
communication environment is a major factor to reducing subscribers’ churn rate. Therefore, it is
important for wireless mobile network operators to ensure stability and efficiency by delivering a
consistent, reliable and high-quality end user (subscriber) satisfaction. This can only be achieve by
conducting a regular network performance monitoring and optimisation as it directly impacts the quality of
the offered services and hence user satisfaction. In this paper, we present the results of network
performance evaluation and optimisation of a GSM network on cell cluster-basis, in Asaba region, South
East Nigeria. We employ a combination of essential key performance indicators such as dropped call rate,
call setup success rate and outage call rate to examine overall QoS and GoS performance of the GSM
network. Our results after network optimisation showed significant performance improvement in terms of
call drop rate, call set up success rate, and call block rate across. Specifically, the end user satisfaction
rate has increased from 94.45%, 87.74%, and 92.85% to 99.05%, 95.38% and 99.03% respectively across
the three GSM cell clusters. The GoS is reduced from 3.33%, 6.60% and 2.38% to 0.00%, 3.70% and
0.00% respectively. Furthermore, ESA, which correspond end points service availability, has improved
from 94.44%, 93.40% and 97.62% to 100%, 96.30% and 100% respectively. In addition, the average
throughput has improved from 73.74kbits/s, 85.06kbits/s and 87.54kbits/s to 77.07kbits/s, 92.38kbits/s and
102kbits/s respectively across the three GSM cell clusters.
Performance analysis and implementation for nonbinary quasi cyclic ldpc decod...ijwmn
Non-binary low-density parity check (NB-LDPC) codes are an extension of binary LDPC codes with
significantly better performance. Although various kinds of low-complexity iterative decoding algorithms
have been proposed, there is a big challenge for VLSI implementation of NBLDPC decoders due to its high
complexity and long latency. In this brief, highly efficient check node processing scheme, which the
processing delay greatly reduced, including Min-Max decoding algorithm and check node unit are
proposed. Compare with previous works, less than 52% could be reduced for the latency of check node
unit. In addition, the efficiency of the presented techniques is design to demonstrate for the (620, 310) NBQC-
LDPC decoder.
S URVEY OF L TE D OWNLINK S CHEDULERS A LGORITHMS IN O PEN A CCESS S IM...ijwmn
he LTE/LTE-A has become a catchphrase for research
and lot of research are being conducted and
carried out in LTE in various issues by various peo
ple. New tools are developed and introduced in the
market to interpret the results of the new algorith
ms proposed by various people. Some tools are open
access which are free to use but some tools are pro
duced by the companies which are not open access. I
n
this paper some of the open access simulation tools
like LTE-Sim and NS-3 are analyzed and LTE downlin
k
scheduler algorithms are simulated using those tool
s. In LTE systems, the downlink scheduler is an
important component for radio resource management;
hence in the context of LTE simulation, a study
between the downlink scheduler models between the s
imulators are performed.
A Grouped System Architecture for Smart Grids Based AMI Communications Over LTE ijwmn
- The document proposes a grouped hierarchical architecture and scheduling technique for smart meter communications over LTE networks. Smart meters are divided into groups, with each group connected to a data concentrator.
- The data concentrator collects smart meter readings and sends a total consumption message to the LTE network on a scheduled basis. It also sends individual smart meter readings.
- This grouped approach reduces the number of LTE modules needed and ensures real-time monitoring while avoiding overloading the LTE network, making LTE a promising solution for smart grid communications.
DISCRETE COSINETRANSFORM-II FOR REDUCTION IN PEAK TO AVERAGE POWER RATIO OF O...ijwmn
Orthogonal frequency Division multiplexing (OFDM) is the most familiar word in telecommunication
and wireless communication systems as it provides enhanced spectral efficiency than Frequency division
multiplexing (FDM).Although it is sustaining an orthogonal relation betweencarriers but high peak to
average power ratio (PAPR) is one of the main disadvantages of OFDM system.Various PAPR reduction
techniques have been used, including techniques based on companding. Incompanding, -Law
companding has potential to reduce the PAPR of OFDMsignals. -Law Companding technique
preserves the dynamic range of samples at low amplitudes.A new method named as precoding which is
having less complexity compared to the other power reduction techniques is proposed to reduce PAPR.
This paper put forward combination of two existing techniques namely -Law Companding Transform
and Discrete Cosine Transform-II precoding technique. The simulation results show that, the proposed
combinedscheme gives better result for PAPR Reduction and results in no distortion.
A COGNITIVE RADIO SCHEME FOR DYNAMIC RESOURCE ALLOCATION BASED ON QOEijwmn
This paper introduces a cognitive radio scheme based on quality of experience (QoE). QoE involves the
mobile end user’s preferences. Considering QoE can lead to an improved cognitive radio resource
management strategy. The cognitive radio scheme aims to manage the traffic flow in dynamic systems; it is
a new way of thinking about dynamic resource management in cellular systems. The Use of the cognitive
radio techniques in cellular systems will improve the resource assignment in wireless communication. The
cognitive radio is a self-aware communication system that aims to use the resource assignment in an
efficient way. The proposed algorithm is very successful at handling the call-blocking rate based on QoS
and QoE.
Long term evolution (LTE) is replacing the 3G services slowly but steadily and become a preferred choice
for data for human to human (H2H) services and now it is becoming preferred choice for voice also. In
some developed countries the traditional 2G services gradually decommissioned from the service and
getting replaced with LTE for all H2H services. LTE provided high downlink and uplink bandwidth
capacity and is one of the technology like mobile ad hoc network (MANET) and vehicular ad hoc network
(VANET) being used as the backbone communication infrastructure for vehicle networking applications.
When Compared to VANET and MANET, LTE provides wide area of coverage and excellent infrastructure
facilities for vehicle networking. This helps in transmitting the vehicle information to the operator and
downloading certain information into the vehicle nodes (VNs) from the operators server. As per the ETSI
publications the number of machine to machine communication (MTC) devices are expected to touch 50
billion by 2020 and this will surpass H2H communication. With growing congestion in the LTE network,
accessing the network for any request from VN especially during peak hour is a big challenge because of
the congestion in random access channel (RACH). In this paper we will analyse this RACH congestion
problem with the data from the live network. Lot of algorithms are proposed for resolving the RACH
congestion on the basis of simulation results so we would like to present some practical data from the live
network to this issue to understand the extent RACH congestion issue in the real time scenario.
Design and analysis of high gain diode predistortionijwmn
This paper presents the design and analysis of a high gain, broadband Schottky and PIN diode based RF
pre-distortion linearizer for TWTA. The circuit is using ABCD matrix approach. The simulation is
performed using Agilent ADS software. We have proposed a new linearizer circuit which can achieve a
high gain compared to existing linearizer designs.
EFFICIENT MIXED MODE SUMMARY FOR MOBILE NETWORKSijwmn
This document proposes a new lossless compression scheme called Mixed Mode Summary-based Lossless Compression for Mobile Networks log files (MMSLC). MMSLC uses the Apriori algorithm to mine frequent patterns from log files. It then assigns unique codes to frequent patterns based on their compression gain. MMSLC exploits correlations between consecutive log files by using a mixed online and offline compression approach. It applies frequent patterns mined from previous files during online compression of current files, while also mining patterns from current files for future compression. The method achieves high compression ratios and provides summaries of frequent patterns to aid in network monitoring.
This document discusses delay tolerant networks (DTNs) and social-aware routing protocols for DTNs. It begins with an overview of DTNs and their characteristics like intermittent connectivity and lack of end-to-end paths. It then describes the DTN architecture including the bundle layer and bundle protocol. Several categories of DTN routing schemes are presented, including message ferry-based, opportunity-based, and prediction-based. Social-aware routing protocols leverage the social ties between nodes to determine message forwarding. Examples discussed include Epidemic Routing, Spray and Wait, and PROPHET. Performance metrics and the ONE simulator are also summarized.
This document discusses delay tolerant networks (DTNs) and social-aware routing protocols for DTNs. It begins with an overview of DTNs and their characteristics like intermittent connectivity and lack of end-to-end paths. It then describes the DTN architecture including the bundle layer and bundle protocol. Several categories of DTN routing schemes are presented, including message ferry-based, opportunity-based, and prediction-based. Social-aware routing protocols leverage the social ties between nodes to determine message forwarding. Examples discussed include Epidemic Routing, Spray and Wait, and PROPHET. Performance metrics and the ONE simulator are also summarized.
Performance evaluation of mofo buffer management technique with different rou...eSAT Journals
Abstract Delay Tolerant Networks (DTNs) uses the store-carry-forward scheme for the delivery of the messages, with this way data transmission can be successfully done despite of the absence of continuous end-to-end paths. The opportunities of message forwarding in such types of networks usually are limited due to the absence of contemporaneous paths. In such networks, the “store-carry-forward” methodology is used for the transmission of the messages to be delivered to their intend destinations in a hop by hop manner. It arises many problems like how to schedule the messages, how to drop the messages in the buffer due to the impulsive nature of the nodes. It also arises many challengeable situations like short contact durations between the two nodes, limited storage capacity of nodes and so on. This paper evaluates the performance of MOFO buffer management technique with three routing protocols i.e. Epidemic, Prophet and MaxProp under variable message buffer sizes (5MB to 40MB). Such evaluation can improve the performance of the opportunistic networks by reducing the overhead ratio, enhancing the delivery rate, minimizing latency average and hop count average in a certain degree. So four performance evaluation metrics namely delivery probability, latency average, overhead ratio and hop count average are used in this study. This study uses ONE (Opportunistic Network Environment) simulator for the performance evaluation of the MOFO buffer management technique and routing protocols. The evaluation results shows that the performance of different protocols can benefit to optimizing the performance of delay tolerant networks in terms of delivery probability, Latency average, Overhead ratio and Hop count average of messages with the increase in message buffer size. Finally, this study suggested that which routing protocol is most suitable with MOFO buffer management technique. Keywords: Delay Tolerant Networks, Buffer Management, Routing Protocols, MOFO, Epidemic, Prophet, MaxProp
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
CONGESTION AWARE SPRAY AND WAIT PROTOCOL: A CONGESTION CONTROL MECHANISM FOR ...ijcsit
In the last few years, the Vehicular Ad-hoc Network (VANET) has come to be an important area of research. Significant research has been conducted to improve the performance of VANETS. One output of further research conducted on VANET is the Vehicular Delay Tolerant Network (VDTN). It is an
application of the mobile DTN where nodes relay messages in the network using a store-carry-forward approach. Due to its high mobility, it suffers frequent disconnections and also congestions at nodes which leads to message drops. To minimize the rate of message drops and so optimize the probability of message delivery so that drivers are increasingly aware of the situation of the road, we propose a congestion
control mechanism: Congestion Aware Spray and Wait (CASaW) protocol in this work so as to optimize the
rate of message delivery to its destination and so increase the awareness of drivers in the vehicular environment thereby improve road safety. The results have shown that our proposition performed better than other classical VDTN protocols in terms of message delivery probability and rate of packet drops performance measures. We used the Opportunistic Networking Environment (ONE) simulator to implement the classical VDTN protocols: the PROPHET protocol, the Epidemic protocol, the MaxProp protocol and
the Spray and Wait Protocol. The simulation scenarios shows a better performance for the congestion control mechanism we propose as it maintains a good message delivery rate as well as minimize the rate of packet losses thereby optimizing the chances of messages getting to their destinations and so improve road safety.
Content Sharing over Smartphone-Based Delay-Tolerant NetworksIJERA Editor
With the growing number of smartphone end users, peer-to-peer ad hoc content giving is likely to occur often. Thus, new articles sharing mechanisms must be developed since traditional information delivery schemes will not be efficient with regard to content sharing due to the sporadic connectivity between smartphones on the market. To obtain data delivery such challenging environments, researchers include proposed the employment of store-carry-forward methodologies, in which a node stores a communication and holds it until a forwarding prospect arises through an encounter together with other nodes. Most past works in this field have dedicated to the conjecture of whether two nodes could encounter the other, without thinking about the place and also time from the encounter. In this particular paper, we propose to her discover-predict-deliver as a possible efficient articles sharing scheme for delay-tolerant touch screen phone networks. In this proposed scheme, contents are usually shared while using the mobility information of people. Specifically, our strategy employs the mobility understanding algorithm to spot places inside your own home and outdoor.
An Extensive Literature Review of Various Routing Protocols in Delay Tolerant...IRJET Journal
This document summarizes an extensive literature review on routing protocols in delay tolerant networks (DTNs). It begins by defining DTNs as wireless networks with intermittent connectivity where nodes use a store-carry-forward mechanism. Common routing protocols for DTNs like epidemic, spray and wait, and prophet are described. The document then reviews several papers that propose and evaluate new routing algorithms or improvements for DTNs, analyzing metrics like delivery ratio, overhead, and latency. Key factors considered include node contact histories, social characteristics, energy constraints, and message prioritization. Finally, it suggests the contact duration between nodes could be an important parameter to further optimize routing in DTNs.
Secure Multicast Communication using Behavioural Measurement Technique in MANET Editor Jacotech
In MANET communication between two mobile nodes are carried out by routing protocol. In MANET each mobile node can directly communicate with other mobile node if both mobile nodes are within transmission range. Otherwise the nodes present in between have to forward the packets for them on network. dynamic and cooperative nature of ad hoc networks presents substantial challenges in securing and detecting attacks in these networks. In this paper we proposed a novel Intrusion Detection and Prevention Scheme (IDPS) for protecting network against Blackhole attack. During the attack, a malicious node captures the data after the positive reply of route existence. Routing in Ad hoc networks has been a challenging task ever since the wireless networks came into existence. In multicasting the sender and communicated with multiple receivers. The routing misbehavior in multicast ODMRP is secured by proposed scheme. The proposed IDPS scheme first to detect the malicious nodes and after that block the activities of malicious nodes. The performance of proposed scheme is evaluated through performance metrics that shows the attacker routing misbehavior and proposed security scheme is provides secure and
vigorous performance in presence blackhole attacker.
The document discusses performance exploration of quality of service (QoS) parameters in mobile ad hoc networks (MANETs). It contains 6 figures analyzing how different QoS parameters are affected by increasing the reporting rate of data packets in the MANET. Figure 2 shows that packet delivery ratio decreases as reporting rate increases due to congestion. Figure 3 shows that packet loss ratio increases with higher reporting rates. Figure 4 indicates that throughput initially increases then decreases with reporting rate. Control overheads and average energy consumption shown in Figures 5 and 6 also are affected by varying the reporting rate in the MANET. The document analyzes how the reporting rate impacts key QoS metrics during data transmission in a MANET.
An Efficient DTN Routing Algorithm for Automatic Crime Information Sharing fo...IJSRD
Delay Tolerant Network shows many issues that are exist in traditional network. Opportunistic network emerge as interesting evolution in MANET. Mobile nodes in the opportunistic network communicate with each other even in case of no route connection. In this paper a kiosk (or hub station) that is connected to villages to establish internet connection. Such kiosk is placed where traffic frequency is high. We will use high frequency sensor in vehicles. When passing through kiosk, high frequency sensor will establish connection to kiosk & kiosk will connect villages to internet. This system is very useful in crime information sharing services. As an example, if there are a person who is victim of any crime or in a trouble condition. He/she have mobile devices connect to internet. They send a trouble message which is passed to near kiosk and passed on to vehicles and forward their information to police station. This system is helpful in villages, where network communication is not proper.
Broadcast Scheduling Protocols in Multi-Hop Mobile Ad hoc NetworksIJCNCJournal
When packets are sending in multi-hop mobile unintended networks numerous problems occur like flooding, rebroadcast, broadcast latency, power conservation and collision. If multiple transmission of packets simultaneously in MANETs that using the slot assignments approach, when additional channels are transmitting at the same time as the first slot allocations, interference may occur at the nodes. Because of the multi-hops data transfer, the network performance is hampered by the constrained bandwidth and therefore the self-initiated topological alterations. Therefore, a broadcast algorithm is important within the mobile ad hoc network for collision control and reliable communication. This paper proposes two new broadcasting protocols: modify SRBS and DSB algorithms. The planned algorithms outperform context of efficiency, reliability, traffic overload and reachability in highly mobile networks is an enhanced performance within the different environments. Evaluation of simulation results with other well-known exiting protocols as DFCN and PEGSP algorithms shows that the proposed protocol performance is best within the wireless network and channel bandwidths are well utilized within the network.
BROADCAST SCHEDULING PROTOCOLS IN MULTIHOP MOBILE AD HOC NETWORKSIJCNCJournal
When packets are sending in multi-hop mobile unintended networks numerous problems occur like
flooding, rebroadcast, broadcast latency, power conservation and collision. If multiple transmission of
packets simultaneously in MANETs that using the slot assignments approach, when additional channels are
transmitting at the same time as the first slot allocations, interference may occur at the nodes. Because of
the multi-hops data transfer, the network performance is hampered by the constrained bandwidth and
therefore the self-initiated topological alterations. Therefore, a broadcast algorithm is important within the
mobile ad hoc network for collision control and reliable communication. This paper proposes two new
broadcasting protocols: modify SRBS and DSB algorithms. The planned algorithms outperform context of
efficiency, reliability, traffic overload and reachability in highly mobile networks is an enhanced
performance within the different environments. Evaluation of simulation results with other well-known
exiting protocols as DFCN and PEGSP algorithms shows that the proposed protocol performance is best
within the wireless network and channel bandwidths are well utilized within the network.
Enhanced Multicast routing for QoS in delay tolerant networksIRJET Journal
This document summarizes research on enhanced multicast routing protocols for quality of service in delay tolerant networks. It proposes a novel multicast routing approach using the MAODV protocol and compares its performance to existing QBMR and DTN-DM protocols. Delay tolerant networks experience intermittent connectivity and long delays. Store-carry-forward is commonly used for data transfer between nodes. The proposed MAODV protocol improves storage and forwarding capabilities of mobile nodes and bundle message communication to multiple destinations. Its performance is evaluated based on metrics like throughput, routing load, and packet delivery fraction compared to existing protocols.
Updatable Queue Protocol Based On TCP For Virtual Reality Environment IJCSEA Journal
The variance in number and types of tasks required to be implemented within Distributed Virtual Environments (DVE) highlights the needs for communication protocols can achieve consistency. In addition, these applications have to handle an increasing number of participants and deal with the difficult problem of scalability. Moreover, the real-time requirements of these applications make the scalability problem more difficult to solve. In this paper, we have implemented Updatable Queue Abstraction protocol (UQA) on TCP (TCP-UQA) and compared it with original TCP, UDP, and Updatable Queue Abstraction based on UDP (UDP-UQA) protocols. Results showed that TCP-UQA was the best in queue management.
Performance improvement of bottleneck link in red vegas over heterogeneous ne...eSAT Journals
1. The document discusses performance improvement of the bottleneck link in RED Vegas over heterogeneous networks. RED Vegas is a variant of TCP Vegas that can better detect random packet losses.
2. It analyzes factors that affect wireless TCP performance such as limited bandwidth, long round trip times, random losses, user mobility, and short flows. It also covers congestion control mechanisms like RED and compares TCP Reno and Vegas.
3. The key findings are that RED Vegas reacts appropriately to losses, improving throughput over heterogeneous networks. It also under-utilizes bandwidth less when random loss rates are high by improving the fast recovery mechanism.
Performance improvement of bottleneck link in red vegas over heterogeneous ne...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Exploiting Wireless Networks, through creation of Opportunity Network – Wirel...ijasuc
Spotting Opportunity today and recognizing the same is the vision of the expert. The wireless
communication network regime is one such environment that offers such a platform for many working
scientific, academic and engineering experts. Henceforth, “Opportunistic-network” is a recent evolution
of the above said phenomena in the wireless community. They function by spontaneous cooperation &
coordination giving birth to a special type network called wireless-mobile-adhoc-network (W-MAN). As
said, these networks are formed instantaneously in a random manner – breaking the conventional
mathematically evolved algorithms’, and provided the quintessential of a network(s) that exist in
neighbourhood(s) or approachable limits. Is more of situational based, exploited for specialized purpose
or advantage, which mimics all the characteristic of a well evolved network. Such networks, lack an endto-end path, contact, cooperation and coordination; which is mainly opportunity based, and break or
even disintegrate soon after discovery, thus the challenge lay in integration, construction and probable
sustenance or even mid-way reconstruction till purpose. One can cite many realistic scenarios fitting to
this situation. For example, wildlife tracking sensor networks, military networks, vehicular ad hoc
networks to mention a few. To transmit information under such circumstances/scenarios researchers have
proposed various efficient forwarding (single copy), replication routing and controlled based schemes. In
this paper, we propose to explore, investigate and analyze most of the schemes [1] [2] [3] [4] [5] [6] and
present the findings of the said scheme by consolidating critical parameters and issues and towards the
end of this paper, algorithms, possible solutions to deal with such complex and dynamic situations
through W-MAN scheme suggested by us.
This document summarizes a research paper that proposes using two-hop relay with erasure coding to increase message delivery probability in mobile ad hoc networks (MANETs). It develops a finite-state absorbing Markov chain framework to model the message delivery process. Based on this, it derives closed-form expressions for message delivery probability under different message lifetimes and sizes. The key findings are that two-hop relay with erasure coding can improve delivery probability compared to traditional routing, and the probability varies based on message parameters and node density.
Performance Analysis of Mobile Adhoc Network Routing Protocols Over Tcppijans
In order to reduce the communication cost and time we are looking forward for successful implementation
of an infrastructure less network like Mobile Ad Hoc Network in all arena of wireless mobile
communication. But still it is a challenge to decide a most appropriate routing protocol for MANET. In
MANET there is no fixed topology due to the mobility of nodes, interference, multipath propagation and
path loss. Since MANET does not use fixed infrastructure rather it always have to find suitable router and
routing path for each communication, existing established routing protocol is not suitable for MANET to
function properly. Different Routing protocols have been proposed to meet the challenges with MANETs.
This paper evaluates the performances of four MANET routing protocols which are DSDV, AODV, DSR
and TORA over TCP, a Transport Layer Protocol. The performance metrics which are considered in this
paper are packet delivery fractions, normalized routing overload, end to end delay and throughput. DSDV
is a proactive protocol and the others are reactive protocols.
Delay Tolerant Networks (DTNs) have high end-to-end latency, which is often faces disconnection, and unreliable wireless connections. It does not mean a delay service instead DTNs provides a service where network imposes disruption or delay. It operates in challenged networks with extremely limited resources such as memory size, CPU processing power etc. This paper presents an efficient trust managing mechanism for providing secure environment. The proposed dynamic trust management protocol uses a dynamic threshold updating which overcomes the problems with time changing dynamic characteristics by dynamically updating the criteria in response to changing network conditions. This reduces overheads and increases the efficient use of routing network even in conditions change. Also the dynamic threshold update reduces the false detection probability of the malicious nodes. To show the effectiveness of the proposed system, a detailed simulation in the presence of selfish and malicious nodes is performed with ONE simulator. Finally a comparative analysis of our proposed routing with previous routing protocols is also performed. The results demonstrate that presented algorithm deals effectively with selfish behavior with providing significant gain on effective delivery ratio in trade off with message overhead and delay
Similar to ROUTING PROTOCOLS FOR DELAY TOLERANT NETWORKS: SURVEY AND PERFORMANCE EVALUATION (20)
ELS: 2.4.1 POWER ELECTRONICS Course objectives: This course will enable stude...Kuvempu University
Introduction - Applications of Power Electronics, Power Semiconductor Devices, Control Characteristics of Power Devices, types of Power Electronic Circuits. Power Transistors: Power BJTs: Steady state characteristics. Power MOSFETs: device operation, switching characteristics, IGBTs: device operation, output and transfer characteristics.
Thyristors - Introduction, Principle of Operation of SCR, Static Anode- Cathode Characteristics of SCR, Two transistor model of SCR, Gate Characteristics of SCR, Turn-ON Methods, Turn-OFF Mechanism, Turn-OFF Methods: Natural and Forced Commutation – Class A and Class B types, Gate Trigger Circuit: Resistance Firing Circuit, Resistance capacitance firing circuit.
Open Channel Flow: fluid flow with a free surfaceIndrajeet sahu
Open Channel Flow: This topic focuses on fluid flow with a free surface, such as in rivers, canals, and drainage ditches. Key concepts include the classification of flow types (steady vs. unsteady, uniform vs. non-uniform), hydraulic radius, flow resistance, Manning's equation, critical flow conditions, and energy and momentum principles. It also covers flow measurement techniques, gradually varied flow analysis, and the design of open channels. Understanding these principles is vital for effective water resource management and engineering applications.
Determination of Equivalent Circuit parameters and performance characteristic...pvpriya2
Includes the testing of induction motor to draw the circle diagram of induction motor with step wise procedure and calculation for the same. Also explains the working and application of Induction generator
Sri Guru Hargobind Ji - Bandi Chor Guru.pdfBalvir Singh
Sri Guru Hargobind Ji (19 June 1595 - 3 March 1644) is revered as the Sixth Nanak.
• On 25 May 1606 Guru Arjan nominated his son Sri Hargobind Ji as his successor. Shortly
afterwards, Guru Arjan was arrested, tortured and killed by order of the Mogul Emperor
Jahangir.
• Guru Hargobind's succession ceremony took place on 24 June 1606. He was barely
eleven years old when he became 6th Guru.
• As ordered by Guru Arjan Dev Ji, he put on two swords, one indicated his spiritual
authority (PIRI) and the other, his temporal authority (MIRI). He thus for the first time
initiated military tradition in the Sikh faith to resist religious persecution, protect
people’s freedom and independence to practice religion by choice. He transformed
Sikhs to be Saints and Soldier.
• He had a long tenure as Guru, lasting 37 years, 9 months and 3 days
Accident detection system project report.pdfKamal Acharya
The Rapid growth of technology and infrastructure has made our lives easier. The
advent of technology has also increased the traffic hazards and the road accidents take place
frequently which causes huge loss of life and property because of the poor emergency facilities.
Many lives could have been saved if emergency service could get accident information and
reach in time. Our project will provide an optimum solution to this draw back. A piezo electric
sensor can be used as a crash or rollover detector of the vehicle during and after a crash. With
signals from a piezo electric sensor, a severe accident can be recognized. According to this
project when a vehicle meets with an accident immediately piezo electric sensor will detect the
signal or if a car rolls over. Then with the help of GSM module and GPS module, the location
will be sent to the emergency contact. Then after conforming the location necessary action will
be taken. If the person meets with a small accident or if there is no serious threat to anyone’s
life, then the alert message can be terminated by the driver by a switch provided in order to
avoid wasting the valuable time of the medical rescue team.
3rd International Conference on Artificial Intelligence Advances (AIAD 2024)GiselleginaGloria
3rd International Conference on Artificial Intelligence Advances (AIAD 2024) will act as a major forum for the presentation of innovative ideas, approaches, developments, and research projects in the area advanced Artificial Intelligence. It will also serve to facilitate the exchange of information between researchers and industry professionals to discuss the latest issues and advancement in the research area. Core areas of AI and advanced multi-disciplinary and its applications will be covered during the conferences.
Tools & Techniques for Commissioning and Maintaining PV Systems W-Animations ...Transcat
Join us for this solutions-based webinar on the tools and techniques for commissioning and maintaining PV Systems. In this session, we'll review the process of building and maintaining a solar array, starting with installation and commissioning, then reviewing operations and maintenance of the system. This course will review insulation resistance testing, I-V curve testing, earth-bond continuity, ground resistance testing, performance tests, visual inspections, ground and arc fault testing procedures, and power quality analysis.
Fluke Solar Application Specialist Will White is presenting on this engaging topic:
Will has worked in the renewable energy industry since 2005, first as an installer for a small east coast solar integrator before adding sales, design, and project management to his skillset. In 2022, Will joined Fluke as a solar application specialist, where he supports their renewable energy testing equipment like IV-curve tracers, electrical meters, and thermal imaging cameras. Experienced in wind power, solar thermal, energy storage, and all scales of PV, Will has primarily focused on residential and small commercial systems. He is passionate about implementing high-quality, code-compliant installation techniques.
Digital Twins Computer Networking Paper Presentation.pptxaryanpankaj78
A Digital Twin in computer networking is a virtual representation of a physical network, used to simulate, analyze, and optimize network performance and reliability. It leverages real-time data to enhance network management, predict issues, and improve decision-making processes.
Blood finder application project report (1).pdfKamal Acharya
Blood Finder is an emergency time app where a user can search for the blood banks as
well as the registered blood donors around Mumbai. This application also provide an
opportunity for the user of this application to become a registered donor for this user have
to enroll for the donor request from the application itself. If the admin wish to make user
a registered donor, with some of the formalities with the organization it can be done.
Specialization of this application is that the user will not have to register on sign-in for
searching the blood banks and blood donors it can be just done by installing the
application to the mobile.
The purpose of making this application is to save the user’s time for searching blood of
needed blood group during the time of the emergency.
This is an android application developed in Java and XML with the connectivity of
SQLite database. This application will provide most of basic functionality required for an
emergency time application. All the details of Blood banks and Blood donors are stored
in the database i.e. SQLite.
This application allowed the user to get all the information regarding blood banks and
blood donors such as Name, Number, Address, Blood Group, rather than searching it on
the different websites and wasting the precious time. This application is effective and
user friendly.
Impartiality as per ISO /IEC 17025:2017 StandardMuhammadJazib15
This document provides basic guidelines for imparitallity requirement of ISO 17025. It defines in detial how it is met and wiudhwdih jdhsjdhwudjwkdbjwkdddddddddddkkkkkkkkkkkkkkkkkkkkkkkwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwioiiiiiiiiiiiii uwwwwwwwwwwwwwwwwhe wiqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqq gbbbbbbbbbbbbb owdjjjjjjjjjjjjjjjjjjjj widhi owqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqq uwdhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhwqiiiiiiiiiiiiiiiiiiiiiiiiiiiiw0pooooojjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjj whhhhhhhhhhh wheeeeeeee wihieiiiiii wihe
e qqqqqqqqqqeuwiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiqw dddddddddd cccccccccccccccv s w c r
cdf cb bicbsad ishd d qwkbdwiur e wetwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwww w
dddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddfffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffw
uuuuhhhhhhhhhhhhhhhhhhhhhhhhe qiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii iqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqq eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc ccccccccccccccccccccccccccccccccccc bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbu uuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuum
m
m mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm m i
g i dijsd sjdnsjd ndjajsdnnsa adjdnawddddddddddddd uw
Supermarket Management System Project Report.pdfKamal Acharya
Supermarket management is a stand-alone J2EE using Eclipse Juno program.
This project contains all the necessary required information about maintaining
the supermarket billing system.
The core idea of this project to minimize the paper work and centralize the
data. Here all the communication is taken in secure manner. That is, in this
application the information will be stored in client itself. For further security the
data base is stored in the back-end oracle and so no intruders can access it.
Call For Paper -3rd International Conference on Artificial Intelligence Advan...
ROUTING PROTOCOLS FOR DELAY TOLERANT NETWORKS: SURVEY AND PERFORMANCE EVALUATION
1. International Journal of Wireless & Mobile Networks (IJWMN) Vol. 7, No. 3, June 2015
DOI : 10.5121/ijwmn.2015.7305 55
ROUTING PROTOCOLS FOR DELAY TOLERANT
NETWORKS: SURVEY AND PERFORMANCE
EVALUATION
Luming Wan, Feiyang Liu, Yawen Chen, and Haibo Zhang
Department of Computer Science, University of Otago, Dunedin, New Zealand
ABSTRACT
Delay Tolerant Networking (DTN) is a promising technology that aims to provide efficient communication
between devices in a network with no guaranteed continuous connectivity. Most existing routing schemes
for DTNs exploit the advantage of message replication to achieve high message delivery rate. However,
these schemes commonly suffer from large communication overhead due to the lack of efficient mechanisms
to control message replication. In this paper we give a brief survey on routing protocols designed for
DTNs, and evaluate the performance of several representative routing protocols including Epidemic, Spray
and Wait, PRoPHET, and 3R through extensive trace-driven simulations. Another objective of this work is
to evaluate the security strength of different routing schemes under common DTN attacks such as the black
hole attack. The results and analysis presented in this paper can provide useful guidance on the design and
selection of routing protocols for given delay-tolerant applications.
KEYWORDS
Delay Tolerant Network, Routing, Performance Evaluation, Communication Overhead.
1. INTRODUCTION
The increasing popularity of ubiquitous computing and communication has led to a huge desire
on data exchange between wireless mobile devices, e.g. cell phones, laptops, tablets, and other
portable devices, regardless of whether any guaranteed end-to-end connection exists. Delay
tolerant networking (DTN) addresses the technical challenges on communication between devices
that lose continuous connectivity due to mobility. Currently, DTNs have been applied to a vast of
areas, including vehicular networks [1], wildlife tracking [2], and social network analysis [3], etc.
However, DTNs are still appearing with numerous of limitations. For example, due to the lack of
synchronous end-to-end connectivity, mobile devices have to carry the messages and forward
them opportunistically upon encountering the destinations, or forward messages to other relays to
help the delivery. This could result in incredible long transmission delay and low message
delivery rate. In addition, the constraints on wireless devices, such as storage capacity,
communication bandwidth, and battery power, can significantly impact the successful message
delivery rate. Hence, routing protocols for DTNs should be able to adapt to the network variation
and be efficient to make use of the available hardware resources.
Recent studies exhibit that most of existing routing protocols designed for DTNs appear with high
similarity in concepts, but their performances are significantly disparate. Epidemic [4] performs
robustly as it blindly floods messages to all devices in the network. Spray and Wait [5] is a
flooding-controlled version of Epidemic, as it simply limits the amount of messages that can be
2. International Journal of Wireless & Mobile Networks (IJWMN) Vol. 7, No. 3, June 2015
56
flooded to the network. In most prediction-based schemes, such as PRoPHET [6], MaxProp [7]
and PER [8], the message forwarding decisions are made based on a quality metric called
encounter predictability which is accumulated from past encounters. However, the above
prediction-based schemes ignore some important encounter information, such as the contact time
and contact duration. Some studies demonstrate that human activities appear with high repetition,
such as weekly meetings. The performance of routing schemes could be enhanced significantly
through the exploitation and utilization of those regular patterns. 3R [9] is a fine-grained history-
based routing scheme, by which the contact time of pair-wise encounters are perfectly recorded.
Due to the maintenance of fine-grained encounter history, the encounter predictability in 3R is
time-dependent, that is, it can be calculated based on only the past contacts that occurred in the
same period as the lifetime of the packet, rather than making a long-term average estimation as in
most prediction-based protocols such as PRoPHET. In addition, 3R is a forwarding-based scheme.
Each node always forwards the original message to the next good relay rather than transmitting
replicas as in all the protocols mentioned above. However, single-copy for each message is not
ideal for DTNs since message could be easily lost due to unstable connectivity, message buffer
overflow, and other uncertainties.
It is difficult to design an absolutely perfect routing protocol that suits to all DTN applications.
The performance of a routing protocol can be affected by a large number of factors, such as the
popularity and active rate of nodes, different setting of parameters for mobile devices, etc. In this
paper, we evaluate the performance of several most popular routing protocols, including
Epidemic, Spray and Wait, PRoPHET, and 3R through trace-driven simulations. Also, we
investigate the impact of different parameters of Spray and Wait and PRoPHET to achieve their
best performance. The aim of this work is to provide some important guidance on routing
protocol design and selection for delay tolerant networks.
On the other hand, it is challenging to develop a secure routing scheme for DTNs due to the vast
constraints such as hardware limitation and unstable end-to-end connectivity. Oversimplified
routing protocol are highly vulnerable to be attacked. Byzantine attacks[14] summarized several
typical categories of attacks in DTNs. Most existing routing protocol for DTN cannot address the
Byzantine attacks. In this paper, we also evaluate the security strength of several protocols with
the black hole attack, which is a representative class of Byzantine attacks.
The reminder of this paper is organized as follows: Section 2 introduces the protocols we are
going to evaluate in detail. Section 3 introduces the data traces and experiment setup. Section 4
shows the performance evaluation in two perspectives. Firstly, we present the impact of different
parameter settings for Spray and Wait, and PRoPHET protocols. Then, we evaluate the
performance of all the protocols with their optimal parameter settings. This includes the general
performance comparison, the average message delivery latency of each protocol, and the
performance difference of the protocols under various packet longevity. In Section 5, we measure
the security strength of the protocols. The paper is concluded in Section 6.
2. ROUTING PROTOCOLS
This section introduces the details of four protocols, Epidemic, PRoPHET, Spray and Wait, and
3R, that will be evaluated in our simulations.
3. International Journal of Wireless & Mobile Networks (IJWMN) Vol. 7, No. 3, June 2015
57
2.1. Epidemic
Epidemic [4] is a pure flooding-based routing protocol for DTNs. Each device (source or relaying
node) always propagates message replicas to all of the contactable nodes until the message is
received by the destination node or the message deadline expires. Due to the nature of unlimited
flooding, Epidemic is able to achieve the best message delivery rate when each node has an
infinite memory buffer, but its performance deteriorates significantly when each node only has
limited resources. This is because numerous of message replicas have to be dumped due to
memory overflow.
2.2. Spray and Wait
Similar to Epidemic, Spray and Wait [5] is also a flooding-based routing protocol, but it controls
the message flooding by directly limiting the number of replicas that an original message can
produce and forward. In spray phase, each message can only propagate a constant number L of
replicas. The source node forwards only one replica to the next node it encounters. The source
node keeps propagating replicas until there is only one left, then the source node and all relays it
encountered before switch to the wait phase. That is, those messages only wait for the destination
node encountering their holders rather than further spreading replicas to other relays.
There is a derivation version of Spray and Wait called Binary Spray and Wait. Instead of perform
pure flooding like Spray and Wait, Binary Spray and Wait propagate its message copies in a
binary tree manner. Suppose a message is allowed to spread L replicas, the source node will
generate L replicas in the beginning and spread them among encountered relays. Suppose a node
A has n (1 < n < L) replicas of message m, and it encounters a node B with no replica of m
previously. A will send 2
n
replicas to B and keep the rest of 2
n
replicas to wait for more
relaying nodes. When only one replica is left in A or any other relaying node, they stop spreading
any replica and wait for encountering the destination node. Spray and Wait can achieve a trade-
off between the delivery rate and transmission overhead by setting a proper limitation of L.
2.3. PRoPHET
PRoPHET [10] is a prediction-based scheme, and it is one of the few DTN routing protocols that
have an IETF draft. It implements a quality metric called encounter predictability to measure the
capability of the encountering nodes whether or not it can transmit the message to the destination.
A replica of a message is propagated to the encountering node if it has a higher predictability than
its holder. This guarantees that each time a message can always be propagated to a better relay.
The encounter predictability is integrated in three perspectives, which are direct probability,
transitivity and ageing. Direct probability is the probability of transmitting a message directly
between two nodes. It is updated whenever two nodes directly encounter each other as follows:
ܲሺܽ, ܾሻ = ܲௗሺܽ, ܾሻ + ൫1 − ߜ − ܲௗሺܽ, ܾሻ൯ × ܲ௨௧ , (1)
where Pold(a,b) is the encounter probability of node a and b before the current encounter occurs,
Pencounter ∈ [0,1] is a scaling factor at which the probability increases on encounters, and δ is a
small positive value to set an upper bound on P(a,b).
Transitivity estimates the probability of indirect contact that through multiple-hop relays, as
shown below:
4. International Journal of Wireless & Mobile Networks (IJWMN) Vol. 7, No. 3, June 2015
58
ܲሺܽ, ܿሻ = ܲௗሺܽ, ܿሻ + ൫1 − ܲௗሺܽ, ܿሻ൯ × ܲሺܽ, ܾሻ × ܲሺܾ, ܿሻ × ߚ , (2)
where P(a,c) is the encounter probability between node a and c through relay node b, Pold(a,c) is
the probability from previous time of update, and β ∈ [0,1] is a scaling factor that decides how
large the impact of transitivity should have on the encounter predictability.
PRoPHET uses an ageing mechanism to decay the encounter predictability and eliminate the
long-time inactive nodes, as shown below:
ܲሺܽ, ܾሻ = ܲௗሺܽ, ܾሻ × ߛ
, (3)
where ߛ ∈ [0,1] is the ageing constant, and K is the number of time units elapsed since the last
time P(a,b) was aged.
As shown in the above Equations, there are three important parameters for PRoPHET protocol:
scaling factors for direct delivery Pencounter, transitivity β, and the ageing constant ߛ. They have
significant influence on the performance and overheads of PRoPHET scheme. PRoPHET can be
an efficient routing protocol by setting the proper parameters if the encountering patterns in
DTNs are predictable, because the messages and replicas are only forwarded to the relays with
more benefits on message delivering. At present, there are two versions of PRoPHET protocol:
PRoPHET'03 [6] and PRoPHET'12 [10]. They have different recommendation settings for these
parameters, while the principle of message forwarding for both versions are basically identical.
PRoPHET'12 [10] has slight improvement on its routing mechanism by filtering out the transient
contacts. These transient contacts are not long enough for nodes to exchange messages, and thus
they should not be counted into history and take effect to the predictability.
2.4. 3R
3R [9] characterizes the encounter history in a fine-grained form by storing more information for
each encounter, including the nodes that the encounter occurs, the start time and the end time of
each encounter. Each node maintains a table for the encounter information of its contacted nodes.
The fine-grained history in a node will group the contacts according to different types of the day
{weekday, weekend}. Each item in the table represents a fixed time interval of the real world (e.g.
1 hour), and it records the overall contact frequency between the table holder and the specified
node at exact the same period in the past. Suppose a message m has a lifetime that spans k slots.
Let Fa
i be the number of contacts of node a that occurred at a time slot i in the past, and Fi
ab be the
number of contacts occurred between node a and b at time slot i, the estimated contact probability
pi
ab at slot i is:
=
ிೌ್
ிೌ
. (4)
Suppose the lifetime of a message m spans k time slots, the overall probability that message m can
be delivered from node a to node b before it expires is estimated by integrating the probabilities
of these k slots as follows:
ܲሺ݇ሻ = 1 − ∏ ሺ1 −
ሻ
ୀ . (5)
Due to the maintenance of fine-grained history, a time-dependent forwarding prediction is
enabled by only figuring out the delivery probability within the lifetime of a message, rather than
5. International Journal of Wireless & Mobile Networks (IJWMN) Vol. 7, No. 3, June 2015
59
calculating a long-term average estimation. Similar to PRoPHET, 3R also compares the
predictability and forwards messages to nodes with higher delivery probability. Whereas, 3R only
directly forwards the original message to the next relay, instead of sending a replica as in
PRoPHET. Due to the predictability calculation based on fine-grained contact history and single-
copy message forwarding, 3R can effectively reduce delivery overheads with no much loss on
message delivery rate.
3. Data Traces and Experiment Setup
3.1. Data Traces
We evaluate the above four representative routing protocols for DTNs with extensive trace-driven
simulations. To increase the accuracy and reliability of our evaluation, we use two realistic DTN
data traces: INFOCOM [11] and MIT Reality [12], which are obtained from the open-source
website CRAWDAD [13].
INFOCOM: This data trace consists of Bluetooth sightings and it records 4 days of contacts
occurred during the INFOCOM'05 conference. In the experiment, 24 internal devices
monitored the network and more than 200 external devices were discovered. Each device has
a scan granularity of 120 seconds, and each scan lasted for 5 seconds.
MIT Reality: This trace contains the contact information including communication,
proximity, and location from faculties and students at MIT over the course of the 2004-2005
academic year. To collect this trace, 89 devices were used to record the contacts, and more
than 20,000 devices were discovered. Each device scans to discover neighbors every 5
minutes. In our simulations, we use the devicespan subtrace that records Bluetooth contacts
for 1 month.
3.2. Experiment Setup
In our simulations, the routing schemes are evaluated using the same message trace and contact
trace. To avoid the negligible delivery rate caused by numerous long-time inactive nodes which
actually seldom communicate, we randomly select the source node and the destination node of a
message from 20 most active nodes during the lifetime of this message. In the INFOCOM trace,
each source generates a message with the probability of 0.15 in every 600 seconds, whereas the
probability is 0.6 in the MIT Reality trace. The lifetime of each message varies from 2 hours to 3
days if not specially notified. The size of each generated message is randomized from 2k bytes to
100k bytes.
For the MIT Reality trace, the network is warmed up for one week at the beginning of each
simulation run. This avoids the inaccurate prediction on encounter probability for prediction-
based protocols, i.e. PRoPHET and 3R, when the network is just booted up. Also, we reserve 3
days at the end of simulations to avoid any message left in the network after the simulation is
completed. During these warm-up and sinking periods, messages are not allowed to be generated.
This process is not available for the INFOCOM data trace, since it only contains 4 days of contact
traces.
4. PERFORMANCE EVALUATION
In this section, we firstly show the performance of Spray and Wait and PRoPHET with different
parameter settings using the INFOCOM data trace, since they have some specific parameters.
6. International Journal of Wireless & Mobile Networks (IJWMN) Vol. 7, No. 3, June 2015
60
Then we investigate the performance of all four protocols, i.e. Epidemic, Spray and Wait,
PRoPHET, and 3R, through trace-driven simulations. The performance of these four protocols are
investigated in three perspectives: different memory buffer sizes, average message delivery
latency, and packet lifetimes. The performance is evaluated using the following three metrics:
average message delivery rate: the proportion between the number of successfully delivered
messages against the number of original messages.
message overhead (MO): the ratio of the number of replicas against the number of original
messages.
communication overhead (CO): the ratio of the difference between the number of delivered
messages and hop-by-hop transmissions to the number of delivered messages.
The parameter setting for Spray and Wait is slightly different in each data trace in accordance
with the characteristic of the data trace. The Binary Spray and Wait protocol is implemented in
the entire experiments as it performs slightly better than its original version. Due to the huge
difference on popularity of nodes in these two traces, the maximum number of replicas for Binary
Spray and Wait with INFOCOM trace is set to 5, and 70 with MIT Reality trace. The parameters
in PRoPHET are configured with the values provided in PRoPHET'12 [10] by default. All the
nodes are set with infinite memory buffer if not specified. All the protocols dump messages using
the First In First Out policy when the message buffer is full, that is, the first message in the buffer
queue (oldest) is dumped to prevent buffer overflow.
4.1. Impact of Parameters for Spray-and-Wait and PRoPHET
Spray-and-Wait: Fig. 1 shows the performance of the original and binary version of Spray and
Wait routing protocol with different maximum number of replicas. In Fig. 1(a), it can be seen that
the original Spray and Wait achieves higher delivery rate than the binary version when the
maximum number of replicas is less than 10. With the further increase on the number of replicas,
the binary version performs better than the original version. That is because the original scheme
can only spread the replicas around the neighbours, while the binary scheme can spread the
replicas more widely in a binary-tree manner if enough number of replicas are allowed. We can
see the delivery rate of both protocols remain steady when the maximum replicas exceeds 40.
The highest average delivery rate achieved by the original and the binary versions are 0.9314 and
0.9382, respectively. That means the number of replicas are enough for two Spray and Wait
protocols with no further benefits for more replicas. Meanwhile, MO and CO for both schemes
appear with the similar increasing trend as shown in Fig. 1(b) and (c). The MO and CO of the
original Spray and Wait increase apparently with the maximum replicas less than 40, and they
stay constant afterwards also due to the limitation on the number of neighbours, whereas both two
kinds of overheads of Binary Spray and Wait grow almost linearly since the replicas can be
spread to more relay nodes on the network. From these figures, it can be seen that with a large
number of replicas, the multi-hop routing of Binary Spray and Wait is able to perform better than
the only two-hop routing in original version, but it suffers almost twice of overheads than the
original version.
7. International Journal of Wireless & Mobile Networks (IJWMN) Vol. 7, No. 3, June 2015
61
Fig. 1. The performance of Spray and Wait with different number of message replicas, (a) delivery rate, (b)
message overhead, (c) communication overhead.
PRoPHET: The performance of PRoPHET routing protocol is critically impacted by the
parameters shown in Table 1. PRoPHET provides totally different recommended parameters in
their 2012 version [10] compared to the 2003 version [6].
Table 1. PROPHET recommended parameters
Parameters Pencounter Β Γ
PRoPHET 2003 0.75 0.25 0.98
PRoPHET 2010 0.5 0.9 0.999
Fig. 2 shows the performance of PRoPHET'03 and PROPHET'12.
In these experiments, each node has infinite memory buffer to store messages and replicas. The
principle of message forwarding for these two versions are basically identical. It can be seen that
in Fig. 2(a), the delivery rate is increased by 0.5% with the parameters of PRoPHET'12 in
comparison with PRoPHET'03. A larger ageing parameter γ makes PROPHET'12 better to
tolerate the variation of contact patterns and achieve higher delivery rate. However, both MO and
CO are raised by 6.1% and 5.4% respectively as shown in Fig. 2(b). This is because a larger β in
PRoPHET'12 leads to higher impact on the transitive connectivity, and a lower Pencounter reduces
the impact of direct delivery. Hence, more replicas need to be generated and forwarded by the
relay nodes.
4.2. Performance Evaluation with Different Memory Sizes
Fig. 2. PRoPHET'03 versus PRoPHET'12, (a) delivery rate, (b) overheads.
8. International Journal of Wireless & Mobile Networks (IJWMN) Vol. 7, No. 3, June 2015
62
In each mobile device, the memory buffer used for message delivery always has a limited size.
The available memory has huge influence on the delivery rate and overheads. We evaluate the
performance of four routing protocols with different memory sizes using INFOCOM and MIT
Reality traces.
(1) INFOCOM Trace: In Fig. 3(a), we evaluate the influence of memory size on the delivery
rate for different routings. It can be seen that the delivery rates of all four routing protocols have a
sharp increasing trend with a small memory buffer (<10MB), and then they tend to remain stable
even if the memory buffer size keeps growing. Binary Spray and Wait has more outstanding
performance than other three routings when each node has a memory buffer of 80M bytes or less.
It reaches its maximum delivery rate of 0.923 with the memory buffer size increasing to 60M
bytes, and the delivery rate tends to be stable afterwards. That is because it is a controlled
flooding scheme (5 replicas) and has less message dropped due to memory overflow than other
routings. When the memory size exceeds 60MB, there will be no message dumps for this routing
and the delivery rate will be stable. Similarly, 3R also has better performance with a smaller
memory buffer size compared with Epidemic and PRoPHET. It has less requirement on memory
size because of single-message and its limitation on message forwarding. However, it reaches the
maximum delivery rate of 0.792 at the memory size of 40M bytes, which is much smaller
compared with the other three protocols. That is because 3R only forwards the original message.
Although the delivery rates of Epidemic and PRoPHET raise slowly, their maximum delivery
rates are higher than 3R and Spray and Wait (0.941 and 0.930 respectively) since they are
memory-hungry schemes. Epidemic protocol needs large amounts of memory for unlimited
flooding and can achieve the highest delivery rate with enough memory. PRoPHET also needs a
large memory size for transmitting the amounts of messages and replicas.
Fig. 3(b) and (c) evaluate the overheads with different memory sizes. We can see that Epidemic
always has the highest MO and CO due to the nature of unlimited flooding. Since it needs to
generate more replicas when encountering relay nodes with high predictability, PRoPHET also
has higher overheads, which is almost half of the overheads as Epidemic. Because the maximum
number of replicas in Binary Spray and Wait is set to 5, the maximum MO and CO of Binary
Spray and Wait scheme tend to be 5 even with a much larger memory size. Since 3R is a single-
message forwarding-only scheme, there is no message overhead. The CO of 3R is also lowest
because the message is only forwarded to a node with higher predictability according to fine-
grained encounter history. The CO of Binary Spray and Wait and 3R appears with a decreasing
trend as the memory size increases, since they have limitations on message forwarding, and a
larger memory size increases the number of delivered messages by reducing message dropping.
Fig. 3. Performance evaluation with different memory sizes using INFOCOM trace, (a) delivery rate, (b)
message overhead, (c) communication overhead.
9. International Journal of Wireless & Mobile Networks (IJWMN) Vol. 7, No. 3, June 2015
63
Fig. 4. Performance evaluation with different memory sizes using MIT Reality trace, (a) delivery rate, (b)
message overhead, (c) communication overhead.
(2) MIT Reality Trace: As shown in Fig. 4(a), the delivery rate of each routing protocol has
similar trend as the memory size increases. However, PRoPHET and 3R have better performance
than Epidemic and Spray and Wait when the memory size is small (<5MB). Since the MIT
Reality trace lasts for 1 month and these two routings can make use of the contact history to get
more accurate prediction for message forwarding, and a smaller memory is relatively enough due
to less replicas and message forwarding. As the memory size increases, Epidemic and Spray and
Wait achieve higher delivery rate because a large number of flooding replicas can be tolerated in
the memory with few of message dumps.
Similarly, the message overhead (MO) in Fig. 4(b) and communication overhead in Fig. 4(c) vary
in the same way as the memory size increases. Since there are more nodes in the MIT Reality
data trace than that in the INFOCOM trace, the overheads of Epidemic are significantly increased.
That means Epidemic is not suitable for DTNs with a large number of devices. We can see that
the overheads of Spray and Wait increase with the increase of maximum allowed replicas (from 5
in INFOCOM trace to 70 in MIT Reality trace). PRoPHET and 3R protocols have lower overhead
for both data traces, which is determined by the popularity of nodes and the activeness of each
node.
From this set of simulations, it can be seen that flooding-based routing protocols can achieve
better delivery rate, but require much larger message memory. Whereas, the prediction-based
routing protocols are more memory efficient, and can achieve desirable delivery rate with very
low overheads if they have accurate prediction on the contact patterns.
4.3. Average Latency
We also conduct a set of simulations to measure the routing efficiency of each DTN protocol in
term of the average message delivery delay. The message delivery latency is defined as the time
span from the time the message is generated until the time when the original message or one of its
copy reaches the destination. We evaluate the average message delivery latency of the four
routing schemes using the INFOCOM and MIT data traces separately with different memory
capacities.
10. International Journal of Wireless & Mobile Networks (IJWMN) Vol. 7, No. 3, June 2015
64
Fig. 5. Average message delivery latency with different memory capacity using trace (a) INFOCOM, (b)
MIT Reality
(1)INFOCOM trace: In Fig.5 (a), all of the protocols appear with a similar increasing trend.
Epidemic spends the least average time on message delivery for all cases studied because it takes
the advantage of blind flooding. Under the situation of a large memory buffer at each node,
Epidemic has the shortest delay because messages can survive longer at nodes. Large number of
message copies of a single message produce a higher chance for the message to reach its
destination through opportunistic encountering between nodes, rather than waiting for frequent
contact nodes like PRoPHET and 3R. On the other hand, when nodes have very limited memory
buffer, most of the message copies have to be discarded because of memory overflow. Thus the
delivery rate is incredible low for Epidemic. However, these limited amount of deliverable
messages still takes the benefit of flooding. The messages can be flooded to the destination
through a relative short path, so that Epidemic still has the shortest delay with the extremely
limited memory at nodes. PRoPHET costs slightly more than Epidemic. It takes the second place
because of its accurate routing prediction. The performance of 3R is relatively poor because of its
single-message-forward mechanism. The use of only a single message is hard to find out the
shortest path to the destination in DTN.
(2)MIT Reality trace: Similar to Fig.5 (a), Epidemic and 3R still get the first and the last place
on the average message delivery delay. However, Spray and Wait outperforms PRoPHET in MIT
Reality trace. This is because this trace contains a much larger node population. The upper limit
of message copy is set to 70, which is a huge increase against 5 in INFOCOM trace. Therefore,
Spray and Wait performs almost the same degree of flooding as Epidemic, so that messages can
be rapidly delivered to their destination through such flooding.
From the results above, flooding-based routing protocol always gain a lower latency than
prediction-based all the time. However, combining the result in Fig. 3 and Fig. 4, flooding-based
protocols have a poor performance when nodes have limited buffer. In contrast, flooding-based
protocols obtains incredible high overheads with large memory buffer. It is necessary to
comprehensively inspect the routing protocols to make a fair comparison, rather than only
observe a single aspect.
4.4. Performance Evaluation with Different Packet Lifetimes
Each message may experience an unpredictable delivery latency in DTNs due to the lack of
guaranteed continuous end-to-end connectivity. Therefore, in order to achieve more effective
communication for DTNs, each message needs a suitable lifetime either by users setting or
11. International Journal of Wireless & Mobile Networks (IJWMN) Vol. 7, No. 3, June 2015
65
default configuration of specific devices. In this set of simulations, we evaluate the influence of
different packet lifetimes for the routing algorithms using INFOCOM and MIT Reality data
traces respectively. We assume each node has an infinite buffer size.
(1) INFOCOM Trace: Fig. 6 shows the delivery rate and overheads of four routing protocols
with different setting of packet lifetimes using the INFOCOM trace. In Fig. 6(a), it can be seen
that for each routing protocol the delivery rate appears with a dramatic increase when the packet
lifetime increases from 6 to 30 hours. For example, the delivery rate increases from 0.454 to
0.832 for 3R routing. The reason is that the probability of directly encountering the destination or
the message delivered to the destination by multi-hop forwarding grows when the packet lifetime
increases. This increasing trend slows down when the packet lifetime exceeds 30 hours. That is
because the data trace only lasts 4 days, and the contact pattern is short-time dependent. The
delivery rate will not increase even with a large packet lifetime since the destination node may
only be active in a short time period. The overheads shown in Fig. 6(b) and (c) also demonstrate
that, for Epidemic and PRoPHET, the overheads increase as the packet lifetime increases, since
more replicas can be generated and forwarded to the destination. Whereas, the lifetime is enough
long for message delivery when it exceeds 30 hours in this trace. The overheads of Spray and
Wait and 3R keep stable with different packet lifetime, because the number of replicas is limited
in Spray and Wait and 3R is a single-message forwarding based scheme.
Fig. 6. Performance evaluation with different packet lifetimes using INFOCOM trace, (a) delivery rate, (b)
message overhead, (c) communication overhead.
Fig. 7. Performance evaluation with different packet lifetimes using MIT Reality trace, (a) delivery rate, (b)
message overhead, (c) communication overhead.
12. International Journal of Wireless & Mobile Networks (IJWMN) Vol. 7, No. 3, June 2015
66
(2) MIT Reality Trace: The simulation results with MIT Reality trace are similar as shown in
Fig. 7. It can be seen in Fig.7 (a) that the delivery rate for all the routing protocols keep growing
as the packet lifetime increases. It is because MIT Reality trace lasts for 1 month and it is long-
time dependent, thus a longer packet lifetime always provides a larger probability of successful
delivery. In this simulation, as shown in Fig.7 (b) and (c) the overheads of Epidemic increase
dramatically both due to longer packet lifetime and larger device population. Whereas, the
overheads variations for other routing protocols are similar to the results using INFOCOM data
trace.
This set of simulations demonstrate that a longer packet lifetime can provide a higher delivery
rate for DTNs, since there is more chance to encounter the destination node either by direct
contact or multi-hop message forwarding. The overheads of flooding-based routings increase
significantly, while the prediction-based routings are more efficient, especially when the DTNs
have long-time dependent contact patterns.
5. SECURITY EXPERIMENTS
5.1. Black Hole Attack and Attack model
We also investigate the security issue inside DTN protocols. Due to the simplicity of routing
design, the protocols we evaluated appear with bare capability to handle hostile attacks from the
unstable DTN environment. To test their security strengths, we perform black hole attack which
interrupt message spread in the network. Similar to the black hole in universe, the black hole
nodes in DTN assimilate all incoming messages and never forward them to others. In the
simulation, we randomly select a fixed amount of attacker nodes from the entire population. The
amount of attacker nodes is decided by a coefficient called attack opportunity, which measures
the badness of DTN environment. The attacker nodes do not originate any message, and all
packets will be destroyed after received by these attacker nodes. To make a fair comparison for
history-based protocols, the attacker nodes still store and update their contact history, thus
sometimes the intruders might be treated as a good relay for some messages. To remove the
impact of further losing packets such as message discard from memory overflow, all of the nodes
in the simulation have infinite buffer size.
5.2. Security Test with Black Hole Attack
(1)INFOCOM: Fig. 8 evaluates the performance of protocols with a steadily increased attack
opportunity using the INFOCOM trace. From Fig. 8 (a), we can see that all of the protocols have
very similar decrease trend when attack opportunity grows, but 3R performs much worse than
others. Due to the nature of single-message-forward scheme, the lost messages are always
irretrievable after they are consumed by attacker nodes. This brings a huge performance degrade
for 3R. The rest of the protocols gain a higher and very similar performance. This is because they
are all replication-based schemes. Destroying a message replica by an attacker node is not a
critical problem for them since the destroyed message might have more copies exist in
somewhere else in the network. In (b) and (c), Epidemic still has the highest overheads because
of its blind flooding. There is a very interesting point is 3R and Spray and Wait which have
obvious increase on communication overhead at the very late stage. The reason of this for 3R is
that nodes forward original messages through multiple hops and most of them eventually meet
attackers, but unfortunately the transmission history of the destroyed messages still have to be
counted into the overheads. This result in 3R has a very poor delivery rate but still gains a great
grow on communication overhead. The reason for Spray and Wait is that it propagates message
13. International Journal of Wireless & Mobile Networks (IJWMN) Vol. 7, No. 3, June 2015
67
copies as a binary tree. The attacker nodes might receive a large number of copies for a single
message (e.g. a attacker nodes could receive 2/n of copies at most when it directly receives them
from the source node) and then destroy all of them. Hence, Spray and Wait is very sensitive to the
amount of message copies. As the attack opportunity grows, the number of successfully delivered
message drops faster than the number of message copies it generated. Hence, the CO of Spray
and Wait is proportional to attack opportunity.
Fig. 8. Performance evaluation with different black hole attack opportunity using INFOCOM trace, (a)
delivery rate, (b) message overhead, (c) communication overhead.
Fig. 9. Performance evaluation with different black hole attack opportunity using MIT Reality trace, (a)
delivery rate, (b) message overhead, (c) communication overhead.
(2)MIT Reality: Fig. 9 shows the result using the MIT Reality trace. It can be seen that the
performance differences between protocols appear much more obvious than that in the
INFOCOM trace. This is because MIT trace contains larger amount of noise and inactive nodes.
In Fig. 9 (a), 3R still has an unexpected performance as above. PRoPHET performs slightly worse
than Epidemic and Spray and Wait when the attack opportunity is less than 0.4, but overtakes
them afterward. It is because PRoPHET takes the advantage of accurate routing prediction
compared to flooding-based protocols. Epidemic has a little bit higher delivery rate than Spray
and wait with a incredible high attack opportunity because Epidemic do not have message
replication limit. In Fig. 8 (b) and (c), it can be seen that Epidemic still has very high overheads.
Different from previous experiments, PRoPHET and Spray and wait have very close overheads.
This is because the node population in MIT is much larger than that in INFOCOM, and Spray and
Wait needs more message copies to achieve a relative high delivery rate.
In this experiments, it can be seen that single-message-forward protocol is not a good solution
under a vulnerable environment. Although all of them did not intentionally provide any solution
for security issue, replication-based protocol performs slightly better in a highly stressed
14. International Journal of Wireless & Mobile Networks (IJWMN) Vol. 7, No. 3, June 2015
68
environment. The overheads of prediction-based protocol are also acceptable, which indicates it is
able to handle the restricted hardware situation in DTNs.
6. CONCLUSION
Due to the property of Delay Tolerant Networks for no guaranteed continuous connectivity,
choosing a proper routing protocol and finding its optimal configuration are challenging
problems. In this paper, we evaluate some existing representative routing protocols for DTNs
through extensive trace-based simulations. Flooding-based routing protocols, such as Epidemic
and Spray and Wait, can achieve better delivery rate by sacrificing the memory, while prediction-
based routings, like PRoPHET and 3R, are more efficient when considering the delivery
overheads. Although all of the protocols we evaluate have rare capability to handle the hostile
attack from adversary users, the prediction-based is able to achieve a relative higher delivery rate.
This paper provides important guidance for routing protocols design. Our future work is to design
an efficient routing protocol for DTNs with high delivery rate and low delivery overheads.
REFERENCES
[1] T. Cao, X. Zhang, L. Kong, X. Liu, W. Shu, and M. Wu, “Traffic aware routing in urban vehicular
networks,” in WCNC, pp. 2004–2009, 2013.
[2] P. Juang, H. Oki, Y. Wang, M. Martonosi, L. S. Peh, and D. Rubenstein, “Energy-efficient computing
for wildlife tracking: Design tradeoffs and early experiences with zebranet,” SIGARCH Comput.
Archit. News, vol. 30, no. 5, pp. 96–107, 2002.
[3] Y. Zhang and J. Zhao, “Social network analysis on data diffusion in delay tolerant networks,” in
MobiHoc, pp. 345–346, 2009.
[4] A. Vahdat and D. Becker, “Epidemic routing for partially-connected ad hoc networks,” tech. rep.,
2000.
[5] T. Spyropoulos, K. Psounis, and C. S. Raghavendra, “Spray and wait: An efficient routing scheme for
intermittently connected mobile networks,” in WDTN, pp. 252–259, 2005.
[6] A. Lindgren, A. Doria, and O. Schel´en, “Probabilistic routing in intermittently connected networks,”
SIGMOBILE Mob. Comput. Commun. Rev., vol. 7, pp. 19–20, July 2003.
[7] J. Burgess, B. Gallagher, D. Jensen, and B. Levine, “Maxprop: Routing for vehicle-based disruption-
tolerant networks,” in INFOCOM, pp. 1–11, April 2006.
[8] Q. Yuan, I. Cardei, and J. Wu, “An efficient prediction-based routing in disruption-tolerant
networks,” IEEE Trans. Parallel Distrib. Syst, vol. 23, no. 1, pp. 19–31, 2012.
[9] L. Vu, Q. Do, and K. Nahrstedt, “3r: Fine-grained encounter-based routing in delay tolerant
networks,” in WoWMoM, pp. 1–6, 2011.
[10] A. Lindgren, A. Doria, E. Davies, and S. Grasic, “Probabilistic routing protocol for intermittently
connected networks,” Internet-Draft, 2012.
[11] J. Scott, R. Gass, J. Crowcroft, P. Hui, C. Diot, and A. Chaintreau, “CRAWDAD data set
cambridge/haggle (v. 2006-01-31).” http://crawdad.org/cambridge/haggle/, 2006.
[12] N. Eagle and A. (Sandy) Pentland, “Reality mining: sensing complex social systems,” Pers. Ubiq.
Comput., vol. 10, no. 4, pp. 255–268, 2006.
[13] D. Kotz, T. Henderson, and I. Abyzov, “CRAWDAD data set dartmouth/campus (v. 2004-12-18).”
http://crawdad.org/dartmouth/campus, 2004.
[14] J. Shen, S. Moh, and I. Chung, "Routing protocols in delay tolerant networks: A comparative survey,"
in Proceeding of 23rd International Technical Conference on Circuits/systems, Computer and
communications, pp. 1577-1580, 2008
15. International Journal of Wireless & Mobile Networks (IJWMN) Vol. 7, No. 3, June 2015
69
Authors
Luming Wan, is a Master candidate from Department of Computer Science, University of Otago, New
Zealand. He obtained B.S. degree from University of Otago, New Zealand in 2012. His research interests
include Delay Tolerant Network (DTN), Social Network, etc.
Feiyang Liu, is a PhD candidate from Department of Computer Science, University of Otago, New
Zealand. He obtained B.S. and M.S. degrees of telecommunication engineering from Xidian University,
China in 2009 and 2012, respectively. His research interests include Network on Chip (NoC), Optical
Network on Chip (ONoC), Delay Tolerant Networks (DTN), etc.
Yawen Chen, Yawen Chen obtained her PhD degree in Computer Science from The University of
Adelaide in Australia in 2008. After her PhD study, she worked as postdoctoral researcher at Royal
Institute of Technology (KTH) in 2009. She has been a Lecturer in the University of Otago in New Zealand
since 2011. Her research interests include resource optimization and performance evaluation in computer
networking and computer architecture (optical networks, interconnection networks, green computing, and
etc).
Haibo Zhang, received the MSc degree in Computer Science from Shandong Normal University, China in
2005, and the PhD degree in Computer Science from the University of Adelaide, Australia in 2009. From
2009 to 2010, he was a postdoctoral research associate at Automatic Control Laboratory, KTH, Sweden.
Currently he is a lecturer at Computer Science department of University of Otago, New Zealand. His
research interests include real-time industrial wireless communications, wireless sensor/ad hoc networks,
delay-tolerant networks, green computing, distributed algorithms and protocol design.