1) The document analyzes opportunistic routing in ad hoc networks, focusing on how to optimize the transmission probability and spectral efficiency.
2) It defines a "forward progress-rate-density" metric to characterize end-to-end performance as the product of transmitter density, average hop distance, and transmission rate.
3) The authors derive an approximation to calculate this metric, and use it to determine the optimal transmission probability and spectral efficiency that maximize end-to-end performance.
FUZZY-CONTROLLED POWER-AWARE PROACTIVE-ACKNOWLEDGEMENT BASED BROADCASTING (FP...cscpconf
Network-wide broadcasting is a fundamental operation for mobile ad hoc networks. Inbroadcasting, a source node sends a message to all other nodes in the network. Under ordinary
flooding procedure, each node transmits the broadcast message to all of its 1-hop downlinkneighbours, i.e. all nodes residing within its radio-range. Receiving the broadcast message all those downlink neighbours reply with an acknowledgement. Since in an ad hoc network a node
may have multiple uplink neighbours, in ordinary flooding procedure, a node is supposed to receive the broadcast message from all those uplink neighbours and send acknowledgement to all of them, generating huge message contention and collision. This is popularly referred to as
the broadcast storm problem. The present article is focused to remove the broadcast redundancy within 2-hop neighbourhood and beyond, as much as possible by prioritizing the 1-
hop downlink neighbours of a node. Priority of a 1-hop downlink neighbour of a node ni increases if it is equipped with a large number of 1-hop downlink neighbours, large radiorange,
high remaining battery power and very small number of uplink neighbours closer to the broadcast source than ni
. ni waits a predefined amount of time to receive proactive
acknowledgements from the 1-hop downlink neighbours having less priority. If it does not receive acknowledgement from those downlink neighbours within the waiting time, it sends the
broadcast message to them. A fuzzy controller named Priority Assignor (PA) is embedded in every node that determines the priority of a 1-hop downlink neighbour. Simulation results firmly
establish that the proposed protocol FP2 B produces high broadcast delivery ratio at muchlesser message cost, compared to other state-of-the-art broadcast algorithms.
This document summarizes a research paper that proposes a Modified Ultra Smart Counter Based Broadcast (MUSCBA) algorithm for mobile ad hoc networks (MANETs). The algorithm dynamically adjusts the counter-based broadcast threshold based on locally available neighborhood information, without requiring location devices. It improves on previous fixed counter-based approaches. Simulation results show the minimum and maximum number of neighbors observed for nodes in different network configurations and densities. The algorithm aims to reduce redundant broadcasts while maintaining high propagation, using only neighborhood data from periodic "Hello" packet exchanges.
This document summarizes a research paper that evaluates the performance of the Dynamic Source Routing (DSR) routing protocol for Variable Bit Rate (VBR) multimedia traffic in mobile ad hoc networks (MANETs) using the Network Simulator 2 (NS-2). The paper conducts simulations of DSR under different scenarios by varying the terrain size, connection rate, and data send rate. It compares the performance of DSR and an enhanced version of DSR based on packet delivery ratio, average end-to-end delay, and optimal path length. The results show that the enhanced DSR performs better in terms of packet delivery but worse in terms of delay and path length compared to the original DSR protocol.
This document discusses performance modeling of MAC layer protocols. It develops equations to evaluate the performance of MAC strategies based on metrics like transmission time, throughput, offered traffic, and transfer delay. The document assumes a generic multi-access network with Poisson packet arrivals and derives formulas for TDMA, ALOHA, slotted ALOHA, and CSMA strategies. It also defines concepts like stability, waiting time, and normalized average transfer delay.
Multihop Routing In Camera Sensor NetworksChuka Okoye
This poster abstract summarizes an experimental study of multihop routing in camera sensor networks. The experiments tested the Collection Tree Protocol (CTP) using CITRIC camera motes and TelosB motes. The experiments varied payload size and delay between packet transmissions to evaluate data rate, reception rate, and latency over different hop counts. The results show that there is a tradeoff between reception rate and latency. Adding a delay between transmissions can improve both data rate and reception rate compared to best effort transmission. The optimal delay depends on the network density and hop count.
Iaetsd security and privacy enhancement using jammer inIaetsd Iaetsd
This document proposes a novel transmission scheme using a cooperative jammer (CJ) to improve security in downlink cellular networks. The scheme aims to securely transmit a private message from a base station to one of K mobile users, while keeping it private from the K-1 other users acting as potential internal eavesdroppers. A CJ is used to generate artificial interference and increase ambiguity at all users, including eavesdroppers, by beamforming. The optimal joint transmission scheme for the base station and CJ is derived to maximize the intended user's secrecy rate. Numerical results show improved performance over not using a CJ. The system model and assumptions and modeling of potential internal eavesdroppers, the CJ, and
Probablistic Inference With Limited InformationChuka Okoye
The document presents a probabilistic approach to answering queries in sensor networks using limited and stochastic information. It uses a Bayesian network to model the relationships between sensor measurements, enemy agent locations, and whether a friendly agent is surrounded. Approximate inference is performed using Markov Chain Monte Carlo sampling to estimate the posterior probability of being surrounded given the sensor data. Simulation results show the algorithm can effectively handle noisy sensor measurements and provide useful estimates even when direct information is limited or unavailable.
International Journal of Engineering Research and Applications (IJERA) aims to cover the latest outstanding developments in the field of all Engineering Technologies & science.
International Journal of Engineering Research and Applications (IJERA) is a team of researchers not publication services or private publications running the journals for monetary benefits, we are association of scientists and academia who focus only on supporting authors who want to publish their work. The articles published in our journal can be accessed online, all the articles will be archived for real time access.
Our journal system primarily aims to bring out the research talent and the works done by sciaentists, academia, engineers, practitioners, scholars, post graduate students of engineering and science. This journal aims to cover the scientific research in a broader sense and not publishing a niche area of research facilitating researchers from various verticals to publish their papers. It is also aimed to provide a platform for the researchers to publish in a shorter of time, enabling them to continue further All articles published are freely available to scientific researchers in the Government agencies,educators and the general public. We are taking serious efforts to promote our journal across the globe in various ways, we are sure that our journal will act as a scientific platform for all researchers to publish their works online.
FUZZY-CONTROLLED POWER-AWARE PROACTIVE-ACKNOWLEDGEMENT BASED BROADCASTING (FP...cscpconf
Network-wide broadcasting is a fundamental operation for mobile ad hoc networks. Inbroadcasting, a source node sends a message to all other nodes in the network. Under ordinary
flooding procedure, each node transmits the broadcast message to all of its 1-hop downlinkneighbours, i.e. all nodes residing within its radio-range. Receiving the broadcast message all those downlink neighbours reply with an acknowledgement. Since in an ad hoc network a node
may have multiple uplink neighbours, in ordinary flooding procedure, a node is supposed to receive the broadcast message from all those uplink neighbours and send acknowledgement to all of them, generating huge message contention and collision. This is popularly referred to as
the broadcast storm problem. The present article is focused to remove the broadcast redundancy within 2-hop neighbourhood and beyond, as much as possible by prioritizing the 1-
hop downlink neighbours of a node. Priority of a 1-hop downlink neighbour of a node ni increases if it is equipped with a large number of 1-hop downlink neighbours, large radiorange,
high remaining battery power and very small number of uplink neighbours closer to the broadcast source than ni
. ni waits a predefined amount of time to receive proactive
acknowledgements from the 1-hop downlink neighbours having less priority. If it does not receive acknowledgement from those downlink neighbours within the waiting time, it sends the
broadcast message to them. A fuzzy controller named Priority Assignor (PA) is embedded in every node that determines the priority of a 1-hop downlink neighbour. Simulation results firmly
establish that the proposed protocol FP2 B produces high broadcast delivery ratio at muchlesser message cost, compared to other state-of-the-art broadcast algorithms.
This document summarizes a research paper that proposes a Modified Ultra Smart Counter Based Broadcast (MUSCBA) algorithm for mobile ad hoc networks (MANETs). The algorithm dynamically adjusts the counter-based broadcast threshold based on locally available neighborhood information, without requiring location devices. It improves on previous fixed counter-based approaches. Simulation results show the minimum and maximum number of neighbors observed for nodes in different network configurations and densities. The algorithm aims to reduce redundant broadcasts while maintaining high propagation, using only neighborhood data from periodic "Hello" packet exchanges.
This document summarizes a research paper that evaluates the performance of the Dynamic Source Routing (DSR) routing protocol for Variable Bit Rate (VBR) multimedia traffic in mobile ad hoc networks (MANETs) using the Network Simulator 2 (NS-2). The paper conducts simulations of DSR under different scenarios by varying the terrain size, connection rate, and data send rate. It compares the performance of DSR and an enhanced version of DSR based on packet delivery ratio, average end-to-end delay, and optimal path length. The results show that the enhanced DSR performs better in terms of packet delivery but worse in terms of delay and path length compared to the original DSR protocol.
This document discusses performance modeling of MAC layer protocols. It develops equations to evaluate the performance of MAC strategies based on metrics like transmission time, throughput, offered traffic, and transfer delay. The document assumes a generic multi-access network with Poisson packet arrivals and derives formulas for TDMA, ALOHA, slotted ALOHA, and CSMA strategies. It also defines concepts like stability, waiting time, and normalized average transfer delay.
Multihop Routing In Camera Sensor NetworksChuka Okoye
This poster abstract summarizes an experimental study of multihop routing in camera sensor networks. The experiments tested the Collection Tree Protocol (CTP) using CITRIC camera motes and TelosB motes. The experiments varied payload size and delay between packet transmissions to evaluate data rate, reception rate, and latency over different hop counts. The results show that there is a tradeoff between reception rate and latency. Adding a delay between transmissions can improve both data rate and reception rate compared to best effort transmission. The optimal delay depends on the network density and hop count.
Iaetsd security and privacy enhancement using jammer inIaetsd Iaetsd
This document proposes a novel transmission scheme using a cooperative jammer (CJ) to improve security in downlink cellular networks. The scheme aims to securely transmit a private message from a base station to one of K mobile users, while keeping it private from the K-1 other users acting as potential internal eavesdroppers. A CJ is used to generate artificial interference and increase ambiguity at all users, including eavesdroppers, by beamforming. The optimal joint transmission scheme for the base station and CJ is derived to maximize the intended user's secrecy rate. Numerical results show improved performance over not using a CJ. The system model and assumptions and modeling of potential internal eavesdroppers, the CJ, and
Probablistic Inference With Limited InformationChuka Okoye
The document presents a probabilistic approach to answering queries in sensor networks using limited and stochastic information. It uses a Bayesian network to model the relationships between sensor measurements, enemy agent locations, and whether a friendly agent is surrounded. Approximate inference is performed using Markov Chain Monte Carlo sampling to estimate the posterior probability of being surrounded given the sensor data. Simulation results show the algorithm can effectively handle noisy sensor measurements and provide useful estimates even when direct information is limited or unavailable.
International Journal of Engineering Research and Applications (IJERA) aims to cover the latest outstanding developments in the field of all Engineering Technologies & science.
International Journal of Engineering Research and Applications (IJERA) is a team of researchers not publication services or private publications running the journals for monetary benefits, we are association of scientists and academia who focus only on supporting authors who want to publish their work. The articles published in our journal can be accessed online, all the articles will be archived for real time access.
Our journal system primarily aims to bring out the research talent and the works done by sciaentists, academia, engineers, practitioners, scholars, post graduate students of engineering and science. This journal aims to cover the scientific research in a broader sense and not publishing a niche area of research facilitating researchers from various verticals to publish their papers. It is also aimed to provide a platform for the researchers to publish in a shorter of time, enabling them to continue further All articles published are freely available to scientific researchers in the Government agencies,educators and the general public. We are taking serious efforts to promote our journal across the globe in various ways, we are sure that our journal will act as a scientific platform for all researchers to publish their works online.
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.
Tree Based Collaboration For Target TrackingChuka Okoye
This document proposes a Dynamic Convoy Tree-Based Collaboration (DCTC) framework to detect and track mobile targets in sensor networks. DCTC uses a dynamic convoy tree structure that includes sensor nodes surrounding the target. As the target moves, the tree is reconfigured by adding or removing nodes to maintain coverage while minimizing energy consumption. The document formalizes reconfiguring the convoy tree as an optimization problem and proposes several practical solutions, including tree expansion/pruning schemes and tree reconfiguration schemes. Extensive experiments evaluate and compare the proposed solutions to an optimal solution.
Optimal Transmit Power and Packet Size in Wireless Sensor Networks in Shadowe...IDES Editor
This paper investigates the effects of
shadowing on the optimal transmit power required to
sustain the network connectivity while maintaining a
predefined maximum tolerable Bit Error Rate (BER) in
a Wireless Sensor Networks (WSN). Optimization of
transmit power is of great importance in WSN since
sensor nodes are battery driven and optimization helps
to increase battery life by reducing inter node
interference significantly. An infinite Automatic Repeat
Request (ARQ) model has been considered to assess the
impact of shadowing and other network conditions on
energy requirement for successful packet transmission in
WSN. We also find the optimal packet length based on
energy efficiency. Effects of shadowing on optimal packet
size and energy efficiency in packetized data
transmission are also investigated. Further energy
consumption is minimized considering a variable packet
length based transmission. Use of optimal packet size
shows a significant reduction in energy spending.
PERFORMANCE ANALYSIS OF BROADCASTING IN MOBILE AD HOC NETWORKS USING CLUSTER ...ijasuc
Broadcasting is a fundamental service in Mobile Ad hoc Networks (MANETs). Cluster based approach
are proposed in literature to reduce the network collision, to reduce delay of packet transmission, to
reduce the energy consumption and improves the throughput. In this paper, a cluster- based
infrastructure is proposed for broadcasting in MANETs. The backbone of the network takes advantage of
the cluster structure and only requires cluster- heads and some selected gateways to forward the
broadcast packet. Each cluster head selects some gateways to forward the packet when it sends the
packet to all the cluster heads in its coverage set. Cluster structures have been simulated using mobile
simulator Glomosim 2.03, which gives better performance to reduce the network collision, to reduce
delay of packet transmission, to reduce the energy consumption and improves the throughput.
Communication by Whispers Paradigm for Short Range Communication in Cognitive...IDES Editor
With ever increasing demand for efficiency
and increased throughput over the wireless domain, we
have now reached a point where in a method for efficient
utilization of the electromagnetic spectrum is in demand.
Cognitive radio provides us with a way in which this demand
could be catered, it does so by using devices which
autonomously adjust their communication parameters to
adapt to the external environment. However, the most
critical of this entire technology is the parameter relating to
the Spectrum Sensing aspects. In order for cognitive radio
devices to properly configure and identify the presence of
a primary carrier in a communication mode, spectrum
sensors and efficient sensing algorithms are required. There
have been many algo- rithms developed in this field.
However, these available spectrum sensing algorithms are
prohibitively expensive to implement in wireless devices that
cater to only short distance communication. In this paper,
we propose a parsimonious spectrum sensing algorithm
which would deal with sensing and couple them with short
distance wireless devices over WiFi networks operating in the
2.4 GHz band. The efficiency parameters are also shown
using demonstrations.
The document proposes a trigger identification service to defend against reactive jammers in wireless sensor networks. The service aims to efficiently identify all sensor nodes whose transmissions trigger jamming attacks, known as trigger nodes. This is achieved through a group testing process using a randomized error-tolerant nonadaptive group testing scheme. The identification of trigger nodes can then be used to exclude them from routing paths and help locate reactive jammers. The paper presents models for the sensor network, jammer behaviors, and analyzes the performance of the proposed identification service.
A Low Overhead Reachability Guaranteed Dynamic Route Discovery Mechanism for ...ijasuc
A crucial issue for a mobile ad hoc network is the handling of a large number of nodes. As more nodes join
the mobile ad hoc network, contention and congestion are more likely. The on demand routing protocols
which broadcasts control packets to discover routes to the destination nodes, generate a high number of
broadcast packets in a larger networks causing contention and collision. We propose an efficient route
discovery protocol, which reduces the number of broadcast packet, using controlled flooding technique.
The simulation results show that the proposed probabilistic flooding decreases the number of control
packets floating in the network during route discovery phase, without lowering the success ratio of path
discoveries. Furthermore, the proposed method adapts to the normal network conditions. The results show
that up to 70% of control packet traffic is saved in route discovery phase when the network is denser.
Enhancing Downlink Performance in Wireless Networks by Simultaneous Multiple ...ambitlick
This document discusses enhancing the downlink performance of wireless networks through simultaneous multiple packet transmission (MPT). MPT allows an access point to simultaneously transmit two packets to two distinct users, effectively doubling throughput. The paper formalizes scheduling packets for transmission as a maximum matching problem in a graph. It also presents a fast approximation algorithm for finding a matching and analyzes how MPT can increase maximum arrival rates and reduce packet delays.
Comparative Analysis of Distortive and Non-Distortive Techniques for PAPR Red...IDES Editor
OFDM is a popular and widely accepted modulation
and multiplexing technique in the area of wireless
communication. IEEE 802.15, a wireless specification defined
for WPAN is an emerging wireless technology for short range
multimedia applications. Two general categories of 802.15
are the low rate 802.15.4 (ZigBee) and high rate 802.15.3
(UWB). In their physical (PHY) layer design, OFDM is a
competing technique due to the various advantages it renders
in the practical wireless media. OFDM has been a popular
technique for many years and adopted as the core technique
in a number of wireless standards. It makes the system more
immune to interference like InterSymbol Interference (ISI)
and InterCarrier Interference (ICI) and dispersive effects of
the channel. It is also a spectrally efficient scheme since the
spectra of the signal are overlapping in nature. Despite these
advantages OFDM suffers from a serious problem of high
Peak to Average Power. This limits the system’s capabilities
and increases the complexity. This paper compares the signal
distortion technique of Amplitude Clipping and the
distortionless technique of SLM for Peak to Average Power
reduction
This paper proposes a lightweight decentralized algorithm for localizing reactive jammers in wireless sensor networks. The algorithm uses a three step process: 1) anomaly detection to identify potential victim nodes, 2) estimation of jammer properties like jamming range, and 3) trigger identification where victim nodes test themselves to identify as trigger or non-trigger nodes. Theoretical analysis and simulation results show that the algorithm can accurately estimate jammer properties while maintaining low time and message complexity. It is also robust against advanced jamming models and provides benefits like improved routing compared to existing techniques.
Simulation of Direct Sequence Spread Spectrum for Wireless Communication Syst...ijtsrd
In this work, a simulation model for Direct Sequence Spread Spectrum (DSSS) scheme for wireless communication systems has been proposed. Unlike the case of a single frequency carrier, the modulated signal in DSSS occupies a much wider bandwidth in order to reduce the possible interferences with narrow band communication signals. In telecommunications, DSSS is a spread spectrum modulation technique used to reduce overall signal interference. The spreading of this signal makes the resulting wideband channel more noisy, allowing for greater resistance to unintentional and intentional interference. Y.V.S Durga Prasad | K. Venkateswarlu"Simulation of Direct Sequence Spread Spectrum for Wireless Communication Systems using Simulink" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-2 | Issue-4 , June 2018, URL: http://www.ijtsrd.com/papers/ijtsrd14118.pdf http://www.ijtsrd.com/engineering/electronics-and-communication-engineering/14118/simulation-of-direct-sequence-spread-spectrum-for-wireless-communication-systems-using-simulink/yvs-durga-prasad
A NEW CLUSTER-BASED WORMHOLE INTRUSION DETECTION ALGORITHM FOR MOBILE AD-HOC ...IJNSA Journal
In multi-hop wireless systems, the need for cooperation among nodes to relay each other's packets exposes them to a wide range of security attacks. A particularly devastating attack is the wormhole attack, where a malicious node records control traffic at one location and tunnels it to another compromised node, possibly far away, which replays it locally. Routing security in ad hoc networks is often equated with strong and feasible node authentication and lightweight cryptography. Unfortunately, the wormhole attack can hardly be defeated by crypto graphical measures, as wormhole attackers do not create separate packets. They simply replay packets already existing on the network, which pass the cryptographic checks. Existing works on wormhole detection have often focused on detection using specialized hardware, such as directional antennas, etc. In this paper, we present a cluster based
counter-measure for the wormhole attack, that alleviates these drawbacks and efficiently mitigates the wormhole attack in MANET. Simulation results on MATLab exhibit the effectiveness of the proposed algorithm in detecting wormhole attacks.
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.
Investigation and Analysis of SNR Estimation in OFDM systemIOSR Journals
Estimation of signal to noise ratio (SNR) of received signal and to transmit the signal effectively for
the modern communication system. The performance of existing non-data-aided (NDA) SNR estimation methods
are substantially degraded for high level modulation scheme such as M-ary amplitude and phase shift keying
(APSK) or quadrature amplitude modulation (QAM).In this paper SNR estimation proposed method which uses
zero point auto-correlation of received signal per block and auto/cross- correlation of decision feedback signal
in orthogonal frequency division multiplexing (OFDM) system. Proposed method can be studied into two types;
Type 1 can estimate SNR by zero point auto-correlation of decision feedback signal based on the second
moment property. Type 2 uses both zero point auto-correlation and cross-correlation based on the fourth
moment property. In block-by-block reception of OFDM system, these two SNR estimation methods can be
possible for the practical implementation due to correlation based the estimation method and they show more
stable estimation performance than the earlier SNR estimation methods.
A collaborative wireless sensor network routingambitlick
This document proposes a new routing scheme called node reliance for wireless sensor networks. Node reliance rates how much each node is relied upon for routing data from sources to sinks. Sources will route through nodes with low reliance ratings to avoid overusing critical nodes and maximize network lifetime. The scheme is evaluated using an example network and compared to other routing methods. Node reliance aims to reduce energy waste from disconnected sources by encouraging collaboration between sources in path selection.
Complexity analysis of multilayer perceptron neural network embedded into a w...Amir Shokri
This document analyzes the computational and communication complexity of implementing a multilayer perceptron neural network across a wireless sensor network. It presents the design of distributing the neural network across the sensor nodes, describes simulations conducted, and analyzes the space, time, and message complexity. The analysis shows that space complexity is minimal due to distributed storage, time complexity is mainly affected by the number of patterns and neurons, and message complexity, which increases faster than time complexity, is primarily affected by the number of hidden and output neurons and total hop distances in the wireless network. The scalability of the design is promising but bounded by the communication costs.
Self-Pruning based Probabilistic Approach to Minimize Redundancy Overhead for...IJCNCJournal
The Broadcast storm problem causes severe interference, intense collision and channel contention, which greatly degrades the QoS performance metrics of the routing protocols. So, we suggest a neighbourhood coverage knowledge probabilistic broadcasting model (NCKPB) integrating with AODV protocol with knowledge on 2-hop neighbourhood coverage; a connectivity function to control a node’s forwarding probability of retransmission to alleviate significant overhead redundancy. Our objective is to minimize the broadcast RREQ overhead while ensuring fair retransmission bandwidth. We considered two more important measures called Saved Rebroadcast and Reachability. The outcomes of NCKPB, Fixed probability (FP) and Flooding (FL) routing schemes are examined under three major operating conditions, such as node density, mobility and traffic load. The NS-2 results demonstrate the efficacy of the proposed NCKPB model by illustrating its performance superiority over all key metrics such as redundancy overhead, end to end latency, throughput, reachability, saved rebroadcast and collision contrast to FP and FL.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Performance analysis of Multiband - OFDM systems using LDPC coder in pulsed -...IDES Editor
In this paper, a combined approach where low density
parity check (LDPC) codes are used to reduce the complexity
and power consumption of pulsed orthogonal frequencydivision
multiplexing (pulsed-OFDM) ultra-wideband (UWB)
systems is described. The proposed system uses LDPC codes
to achieve higher code rates without using convolution
encoding and puncturing thereby reducing the complexity and
power consumption of pulsed-OFDM system. The LDPCpulsed-
OFDM system achieves channel capacity with different
code rates and has good performance in different channel
fading scenarios. The pulsed OFDM system is used where
pulsed signals could spread the frequency spectrum of the
OFDM signal. The performance of LDPC-pulsed-OFDM
system for wireless personal area networks (WPAN) is
analyzed for different UWB indoor propagation channels (CM3
and CM4) provided by the IEEE 802.15.3a Standard activity
committee. To establish this, a design of LDPC-pulsed-OFDM
system using the digital video broadcasting-satellite-second
generation (DVB-S2) standard and provide the simulation
results for the different code rates supported by LDPC codes
is presented.
An ad-hoc routing protocol is a convention, or standard, that controls how nodes decide which way to route packets between computing devices in a mobile ad hoc network .
In ad-hoc networks, nodes are not familiar with the topology of their networks; instead, they have to discover it.The basic idea is that a new node may announce its presence and should listen for announcements broadcast by its neighbors.Each node learns about nodes nearby and how to reach them, and may announce that it, too, can reach them
CentOS es un sistema operativo libre y de código abierto clonado de Red Hat Enterprise Linux. Se compila a partir del código fuente público de RHEL pero no tiene soporte comercial. CentOS usa YUM como herramienta de gestión de paquetes y soporta arquitecturas como x86, x86-64 e IBM Power. Ha habido numerosas versiones lanzadas que se basan en diferentes versiones de RHEL.
Touch lamp hidden camera with built in dvr (digital video recorder) (buy or ...dplsurve
This document describes and advertises a touch lamp hidden camera with a built-in digital video recorder (DVR). It can be rented for $95 per week. The camera is motion activated and records high quality video and photos with timestamps. It has options for different camera resolutions. The website that sells these products also offers many other hidden camera devices that can be integrated into common household items to covertly record video.
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.
Tree Based Collaboration For Target TrackingChuka Okoye
This document proposes a Dynamic Convoy Tree-Based Collaboration (DCTC) framework to detect and track mobile targets in sensor networks. DCTC uses a dynamic convoy tree structure that includes sensor nodes surrounding the target. As the target moves, the tree is reconfigured by adding or removing nodes to maintain coverage while minimizing energy consumption. The document formalizes reconfiguring the convoy tree as an optimization problem and proposes several practical solutions, including tree expansion/pruning schemes and tree reconfiguration schemes. Extensive experiments evaluate and compare the proposed solutions to an optimal solution.
Optimal Transmit Power and Packet Size in Wireless Sensor Networks in Shadowe...IDES Editor
This paper investigates the effects of
shadowing on the optimal transmit power required to
sustain the network connectivity while maintaining a
predefined maximum tolerable Bit Error Rate (BER) in
a Wireless Sensor Networks (WSN). Optimization of
transmit power is of great importance in WSN since
sensor nodes are battery driven and optimization helps
to increase battery life by reducing inter node
interference significantly. An infinite Automatic Repeat
Request (ARQ) model has been considered to assess the
impact of shadowing and other network conditions on
energy requirement for successful packet transmission in
WSN. We also find the optimal packet length based on
energy efficiency. Effects of shadowing on optimal packet
size and energy efficiency in packetized data
transmission are also investigated. Further energy
consumption is minimized considering a variable packet
length based transmission. Use of optimal packet size
shows a significant reduction in energy spending.
PERFORMANCE ANALYSIS OF BROADCASTING IN MOBILE AD HOC NETWORKS USING CLUSTER ...ijasuc
Broadcasting is a fundamental service in Mobile Ad hoc Networks (MANETs). Cluster based approach
are proposed in literature to reduce the network collision, to reduce delay of packet transmission, to
reduce the energy consumption and improves the throughput. In this paper, a cluster- based
infrastructure is proposed for broadcasting in MANETs. The backbone of the network takes advantage of
the cluster structure and only requires cluster- heads and some selected gateways to forward the
broadcast packet. Each cluster head selects some gateways to forward the packet when it sends the
packet to all the cluster heads in its coverage set. Cluster structures have been simulated using mobile
simulator Glomosim 2.03, which gives better performance to reduce the network collision, to reduce
delay of packet transmission, to reduce the energy consumption and improves the throughput.
Communication by Whispers Paradigm for Short Range Communication in Cognitive...IDES Editor
With ever increasing demand for efficiency
and increased throughput over the wireless domain, we
have now reached a point where in a method for efficient
utilization of the electromagnetic spectrum is in demand.
Cognitive radio provides us with a way in which this demand
could be catered, it does so by using devices which
autonomously adjust their communication parameters to
adapt to the external environment. However, the most
critical of this entire technology is the parameter relating to
the Spectrum Sensing aspects. In order for cognitive radio
devices to properly configure and identify the presence of
a primary carrier in a communication mode, spectrum
sensors and efficient sensing algorithms are required. There
have been many algo- rithms developed in this field.
However, these available spectrum sensing algorithms are
prohibitively expensive to implement in wireless devices that
cater to only short distance communication. In this paper,
we propose a parsimonious spectrum sensing algorithm
which would deal with sensing and couple them with short
distance wireless devices over WiFi networks operating in the
2.4 GHz band. The efficiency parameters are also shown
using demonstrations.
The document proposes a trigger identification service to defend against reactive jammers in wireless sensor networks. The service aims to efficiently identify all sensor nodes whose transmissions trigger jamming attacks, known as trigger nodes. This is achieved through a group testing process using a randomized error-tolerant nonadaptive group testing scheme. The identification of trigger nodes can then be used to exclude them from routing paths and help locate reactive jammers. The paper presents models for the sensor network, jammer behaviors, and analyzes the performance of the proposed identification service.
A Low Overhead Reachability Guaranteed Dynamic Route Discovery Mechanism for ...ijasuc
A crucial issue for a mobile ad hoc network is the handling of a large number of nodes. As more nodes join
the mobile ad hoc network, contention and congestion are more likely. The on demand routing protocols
which broadcasts control packets to discover routes to the destination nodes, generate a high number of
broadcast packets in a larger networks causing contention and collision. We propose an efficient route
discovery protocol, which reduces the number of broadcast packet, using controlled flooding technique.
The simulation results show that the proposed probabilistic flooding decreases the number of control
packets floating in the network during route discovery phase, without lowering the success ratio of path
discoveries. Furthermore, the proposed method adapts to the normal network conditions. The results show
that up to 70% of control packet traffic is saved in route discovery phase when the network is denser.
Enhancing Downlink Performance in Wireless Networks by Simultaneous Multiple ...ambitlick
This document discusses enhancing the downlink performance of wireless networks through simultaneous multiple packet transmission (MPT). MPT allows an access point to simultaneously transmit two packets to two distinct users, effectively doubling throughput. The paper formalizes scheduling packets for transmission as a maximum matching problem in a graph. It also presents a fast approximation algorithm for finding a matching and analyzes how MPT can increase maximum arrival rates and reduce packet delays.
Comparative Analysis of Distortive and Non-Distortive Techniques for PAPR Red...IDES Editor
OFDM is a popular and widely accepted modulation
and multiplexing technique in the area of wireless
communication. IEEE 802.15, a wireless specification defined
for WPAN is an emerging wireless technology for short range
multimedia applications. Two general categories of 802.15
are the low rate 802.15.4 (ZigBee) and high rate 802.15.3
(UWB). In their physical (PHY) layer design, OFDM is a
competing technique due to the various advantages it renders
in the practical wireless media. OFDM has been a popular
technique for many years and adopted as the core technique
in a number of wireless standards. It makes the system more
immune to interference like InterSymbol Interference (ISI)
and InterCarrier Interference (ICI) and dispersive effects of
the channel. It is also a spectrally efficient scheme since the
spectra of the signal are overlapping in nature. Despite these
advantages OFDM suffers from a serious problem of high
Peak to Average Power. This limits the system’s capabilities
and increases the complexity. This paper compares the signal
distortion technique of Amplitude Clipping and the
distortionless technique of SLM for Peak to Average Power
reduction
This paper proposes a lightweight decentralized algorithm for localizing reactive jammers in wireless sensor networks. The algorithm uses a three step process: 1) anomaly detection to identify potential victim nodes, 2) estimation of jammer properties like jamming range, and 3) trigger identification where victim nodes test themselves to identify as trigger or non-trigger nodes. Theoretical analysis and simulation results show that the algorithm can accurately estimate jammer properties while maintaining low time and message complexity. It is also robust against advanced jamming models and provides benefits like improved routing compared to existing techniques.
Simulation of Direct Sequence Spread Spectrum for Wireless Communication Syst...ijtsrd
In this work, a simulation model for Direct Sequence Spread Spectrum (DSSS) scheme for wireless communication systems has been proposed. Unlike the case of a single frequency carrier, the modulated signal in DSSS occupies a much wider bandwidth in order to reduce the possible interferences with narrow band communication signals. In telecommunications, DSSS is a spread spectrum modulation technique used to reduce overall signal interference. The spreading of this signal makes the resulting wideband channel more noisy, allowing for greater resistance to unintentional and intentional interference. Y.V.S Durga Prasad | K. Venkateswarlu"Simulation of Direct Sequence Spread Spectrum for Wireless Communication Systems using Simulink" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-2 | Issue-4 , June 2018, URL: http://www.ijtsrd.com/papers/ijtsrd14118.pdf http://www.ijtsrd.com/engineering/electronics-and-communication-engineering/14118/simulation-of-direct-sequence-spread-spectrum-for-wireless-communication-systems-using-simulink/yvs-durga-prasad
A NEW CLUSTER-BASED WORMHOLE INTRUSION DETECTION ALGORITHM FOR MOBILE AD-HOC ...IJNSA Journal
In multi-hop wireless systems, the need for cooperation among nodes to relay each other's packets exposes them to a wide range of security attacks. A particularly devastating attack is the wormhole attack, where a malicious node records control traffic at one location and tunnels it to another compromised node, possibly far away, which replays it locally. Routing security in ad hoc networks is often equated with strong and feasible node authentication and lightweight cryptography. Unfortunately, the wormhole attack can hardly be defeated by crypto graphical measures, as wormhole attackers do not create separate packets. They simply replay packets already existing on the network, which pass the cryptographic checks. Existing works on wormhole detection have often focused on detection using specialized hardware, such as directional antennas, etc. In this paper, we present a cluster based
counter-measure for the wormhole attack, that alleviates these drawbacks and efficiently mitigates the wormhole attack in MANET. Simulation results on MATLab exhibit the effectiveness of the proposed algorithm in detecting wormhole attacks.
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.
Investigation and Analysis of SNR Estimation in OFDM systemIOSR Journals
Estimation of signal to noise ratio (SNR) of received signal and to transmit the signal effectively for
the modern communication system. The performance of existing non-data-aided (NDA) SNR estimation methods
are substantially degraded for high level modulation scheme such as M-ary amplitude and phase shift keying
(APSK) or quadrature amplitude modulation (QAM).In this paper SNR estimation proposed method which uses
zero point auto-correlation of received signal per block and auto/cross- correlation of decision feedback signal
in orthogonal frequency division multiplexing (OFDM) system. Proposed method can be studied into two types;
Type 1 can estimate SNR by zero point auto-correlation of decision feedback signal based on the second
moment property. Type 2 uses both zero point auto-correlation and cross-correlation based on the fourth
moment property. In block-by-block reception of OFDM system, these two SNR estimation methods can be
possible for the practical implementation due to correlation based the estimation method and they show more
stable estimation performance than the earlier SNR estimation methods.
A collaborative wireless sensor network routingambitlick
This document proposes a new routing scheme called node reliance for wireless sensor networks. Node reliance rates how much each node is relied upon for routing data from sources to sinks. Sources will route through nodes with low reliance ratings to avoid overusing critical nodes and maximize network lifetime. The scheme is evaluated using an example network and compared to other routing methods. Node reliance aims to reduce energy waste from disconnected sources by encouraging collaboration between sources in path selection.
Complexity analysis of multilayer perceptron neural network embedded into a w...Amir Shokri
This document analyzes the computational and communication complexity of implementing a multilayer perceptron neural network across a wireless sensor network. It presents the design of distributing the neural network across the sensor nodes, describes simulations conducted, and analyzes the space, time, and message complexity. The analysis shows that space complexity is minimal due to distributed storage, time complexity is mainly affected by the number of patterns and neurons, and message complexity, which increases faster than time complexity, is primarily affected by the number of hidden and output neurons and total hop distances in the wireless network. The scalability of the design is promising but bounded by the communication costs.
Self-Pruning based Probabilistic Approach to Minimize Redundancy Overhead for...IJCNCJournal
The Broadcast storm problem causes severe interference, intense collision and channel contention, which greatly degrades the QoS performance metrics of the routing protocols. So, we suggest a neighbourhood coverage knowledge probabilistic broadcasting model (NCKPB) integrating with AODV protocol with knowledge on 2-hop neighbourhood coverage; a connectivity function to control a node’s forwarding probability of retransmission to alleviate significant overhead redundancy. Our objective is to minimize the broadcast RREQ overhead while ensuring fair retransmission bandwidth. We considered two more important measures called Saved Rebroadcast and Reachability. The outcomes of NCKPB, Fixed probability (FP) and Flooding (FL) routing schemes are examined under three major operating conditions, such as node density, mobility and traffic load. The NS-2 results demonstrate the efficacy of the proposed NCKPB model by illustrating its performance superiority over all key metrics such as redundancy overhead, end to end latency, throughput, reachability, saved rebroadcast and collision contrast to FP and FL.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Performance analysis of Multiband - OFDM systems using LDPC coder in pulsed -...IDES Editor
In this paper, a combined approach where low density
parity check (LDPC) codes are used to reduce the complexity
and power consumption of pulsed orthogonal frequencydivision
multiplexing (pulsed-OFDM) ultra-wideband (UWB)
systems is described. The proposed system uses LDPC codes
to achieve higher code rates without using convolution
encoding and puncturing thereby reducing the complexity and
power consumption of pulsed-OFDM system. The LDPCpulsed-
OFDM system achieves channel capacity with different
code rates and has good performance in different channel
fading scenarios. The pulsed OFDM system is used where
pulsed signals could spread the frequency spectrum of the
OFDM signal. The performance of LDPC-pulsed-OFDM
system for wireless personal area networks (WPAN) is
analyzed for different UWB indoor propagation channels (CM3
and CM4) provided by the IEEE 802.15.3a Standard activity
committee. To establish this, a design of LDPC-pulsed-OFDM
system using the digital video broadcasting-satellite-second
generation (DVB-S2) standard and provide the simulation
results for the different code rates supported by LDPC codes
is presented.
An ad-hoc routing protocol is a convention, or standard, that controls how nodes decide which way to route packets between computing devices in a mobile ad hoc network .
In ad-hoc networks, nodes are not familiar with the topology of their networks; instead, they have to discover it.The basic idea is that a new node may announce its presence and should listen for announcements broadcast by its neighbors.Each node learns about nodes nearby and how to reach them, and may announce that it, too, can reach them
CentOS es un sistema operativo libre y de código abierto clonado de Red Hat Enterprise Linux. Se compila a partir del código fuente público de RHEL pero no tiene soporte comercial. CentOS usa YUM como herramienta de gestión de paquetes y soporta arquitecturas como x86, x86-64 e IBM Power. Ha habido numerosas versiones lanzadas que se basan en diferentes versiones de RHEL.
Touch lamp hidden camera with built in dvr (digital video recorder) (buy or ...dplsurve
This document describes and advertises a touch lamp hidden camera with a built-in digital video recorder (DVR). It can be rented for $95 per week. The camera is motion activated and records high quality video and photos with timestamps. It has options for different camera resolutions. The website that sells these products also offers many other hidden camera devices that can be integrated into common household items to covertly record video.
Mobile Minions is a mobile employee management system that aims to help companies manage their mobile salespeople and penetrate new competitive locations. The system provides data storage and access through a web UI, but implementing its full scope faces challenges due to its complexity.
CentOS es una distribución de Linux gratuita basada en Red Hat Enterprise Linux. Funciona como un sistema operativo virtual que permite ejecutar múltiples sistemas operativos de forma simultánea aunque con menor velocidad. CentOS ha dominado el hosting de Linux en los últimos años reemplazando a Red Hat, debido a su gratuidad, seguridad y características.
Este documento presenta información sobre el sistema operativo CentOS. Brevemente describe que CentOS es una distribución de Linux gratuita basada en Red Hat Enterprise Linux, con soporte de 7 años. Explica su historia desde la versión 3.1 en 2004 hasta la versión actual 5, y cubre temas como su escritorio, requerimientos de hardware y arquitecturas soportadas.
CentOS es una distribución de Linux gratuita y de código abierto basada en Red Hat Enterprise Linux. Ofrece un sistema operativo estable y seguro ideal para entornos de producción. CentOS incluye aplicaciones populares como OpenOffice, software de red como Samba, y tiene requisitos mínimos de hardware. Sus principales ventajas son la seguridad, estabilidad, bajos recursos y actualizaciones continuas.
Este documento presenta una introducción a la administración de sistemas Linux CentOS. Explica qué es CentOS, revisa comandos básicos de Linux como ls, cd y mount, y cubre temas como inicio y apagado del sistema, búsqueda de archivos, y movimiento de archivos. El objetivo es proporcionar información introductoria para nuevos administradores de sistemas Linux CentOS.
Este documento proporciona información sobre la evolución de los microprocesadores Intel desde el 4004 en 1971 hasta el 8088 en 1979. Describe los principales hitos como el 4004 que fue el primer microprocesador en un chip, el 8080 que permitió la creación de los primeros microcomputadores personales y el 8088 que fue el primer microprocesador de 16 bits usado en los primeros PCs.
This document summarizes an academic paper that proposes a new Energy Minimized Opportunistic Routing (EMOR) protocol for wireless sensor networks. EMOR aims to enhance source location privacy and minimize energy usage. It uses opportunistic routing to dynamically change paths from source to destination, hiding the source location. Additionally, EMOR reduces transmission power of each node to minimize energy consumption while still reliably transmitting packets. The paper reviews related work on source privacy and energy efficiency in wireless routing protocols and presents simulation results showing EMOR provides better source privacy compared to existing opportunistic routing while also reducing energy usage.
This document discusses optimal multicast capacity and delay tradeoffs in mobile ad hoc networks (MANETs). It considers four node mobility models and two mobility timescales: fast and slow. It characterizes the optimal multicast capacity for each model given a delay constraint and develops a scheme that achieves a capacity-delay tradeoff close to the upper bound up to a logarithmic factor. It also studies heterogeneous networks with infrastructure support.
To Get any Project for CSE, IT ECE, EEE Contact Me @ 09666155510, 09849539085 or mail us - ieeefinalsemprojects@gmail.com-Visit Our Website: www.finalyearprojects.org
This document summarizes a research paper that proposes a method for identifying reliable nodes in an ad hoc wireless network to form stable routing paths. The method evaluates nodes based on their transmission range, signal strength, packet forwarding capacity, and position. Nodes meeting certain thresholds for these metrics are identified as reliable and added to a neighbor routing table. Simulation results showed this selective approach to identifying reliable nodes performed better than the traditional AODV routing protocol at maintaining stable routes in the face of node mobility.
This document summarizes a research paper that proposes a selective on-demand protocol for finding reliable nodes to form stable paths in ad hoc networks. The protocol identifies reliable adjacent nodes based on metrics like transmission range, signal strength, and node capacity. It extends the AODV routing protocol by storing information on reliable nodes in the routing table. Simulation results show the approach improves network stability and performance over the traditional AODV protocol.
1) The document presents the OPRAH protocol, which leverages the broadcast nature of wireless networks to enable opportunistic routing.
2) During route setup, RREQ packets are flooded to discover multiple paths from source to destination, filling nodes' route tables with multiple upstream paths.
3) During data forwarding, the best next hop is selected opportunistically based on link quality, avoiding settling on a single suboptimal path.
1) The document proposes a new opportunistic routing protocol called OPRAH for dynamic ad hoc networks that leverages the broadcast nature of wireless transmissions.
2) It motivates opportunistic routing by showing through simulations that typical shortest path routes in dynamic networks with fading can vary dramatically over time.
3) The OPRAH protocol works on top of the link layer and uses promiscuous listening to opportunistically select intermediate forwarders that have the best chance of reliably delivering packets toward the destination.
The Impact of Signal Strength over Routing Protocols in Wireless NetworksDr. Amarjeet Singh
In ad hoc routing protocols the source node
may need an intermediate nodes to transmit the packets into
the destination if the destination is not within transmission
range of the source. This paper studies the impact of signal
strength of nodes over ad hoc routing protocols and explains
an important effect of signal strength on ad hoc routing
protocols in four different directions including the routes and
the nodes. As a result the study give an important
improvement in ad hoc routing protocols when using signal
strength compared to other ad hoc routing protocols without
considering signal strength.
Dynamic Sub-Channel Allocation in Multiuser OFDM Systems to Achieve Variable ...IDES Editor
This document summarizes a research paper that proposes a dynamic sub-channel allocation algorithm in multiuser OFDM systems to achieve variable data rates. It investigates allocating frequency sub-channels adaptively among users to take advantage of channel diversity and maximize capacity while maintaining proportional fairness. The algorithm first allocates sub-channels assuming equal power distribution, then optimizes power allocation. Simulation results show the algorithm efficiently distributes capacity according to proportional rate constraints.
Rate Adaptation for Time Varying Channels Using Distributed Relay Selectionpaperpublications3
Abstract: Fixed systems used in cooperative communication suffer from multiplexing loss and low spectral efficiency due to the half duplex constraint of relays. To improve the multiplexing gain, successive relaying is proposed. This allows concurrent transmission of the source and relays. However, the severe inter-relay interference becomes a key challenge. Here Rate Adaptation for Time Varying Channels Using Distributed Relay Selection is proposed, which is capable of adapting the relay’s rate using distributed relay selection.
DOTNET 2013 IEEE MOBILECOMPUTING PROJECT Delay optimal broadcast for multihop...IEEEGLOBALSOFTTECHNOLOGIES
To Get any Project for CSE, IT ECE, EEE Contact Me @ 09849539085, 09966235788 or mail us - ieeefinalsemprojects@gmail.com-Visit Our Website: www.finalyearprojects.org
JPN1418 PSR: A Lightweight Proactive Source Routing Protocol For Mobile Ad H...chennaijp
Get the latest IEEE ns2 projects in JP INFOTECH; we are having following category wise projects like Industrial Informatics, Vehicular Technology, Networking, WSN and Manet.
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International Journal of Engineering Research and Development (IJERD)IJERD Editor
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Performance of dsdv protocol based on different propagation model with variIAEME Publication
This document discusses the performance of the DSDV routing protocol under different propagation models and topologies in mobile ad hoc networks (MANETs). It first provides background on MANET routing protocols including DSDV and describes two propagation models - free space and two ray ground. It then discusses a simulation study comparing the performance of DSDV using these propagation models with various network topologies. The results show that the propagation model has a significant impact on routing protocol performance in MANETs.
The document proposes a distributed adaptive opportunistic routing scheme for wireless ad hoc networks. It uses a reinforcement learning framework to route packets opportunistically even without knowledge of channel statistics or network models. This approach jointly addresses learning and routing opportunistically by exploiting transmission successes. Nodes learn to optimally explore and exploit opportunities in the network to minimize the expected average per packet cost of routing from source to destination.
Power control in mobile ad hoc network using NS2 simulatorIRJET Journal
This document proposes a cross-layer design approach called CLPC (Cross Layer Power Control) to improve power control in mobile ad hoc networks. The CLPC approach allows for interaction between the physical, MAC, and network layers to dynamically control transmission power based on received signal strength values. It was tested using the NS2 simulator and found to perform better than AODV in terms of packet delivery ratio, end-to-end delay, and routing overhead. The CLPC approach aims to find reliable routes between source and destination nodes by averaging RSS values and adjusting transmission power accordingly.
Disruption Tolerant Network Coding scenarios often rises from mobile wireless networks where due to limited transmission power, fast node mobility,sparse node density, and frequent equipment failures, there is often no contemporaneous path from the source to destination nodes. Before going to the depth of DTN, it is recommended to review traditional non-coding routing schemes for broadcast and unicast applications in DTNs, and the basic operations of Random Linear Coding (RLC).
A STUDY ON RECEIVER BASED MULTICAST FOR WIRELESS SENSOR NETWORKSpharmaindexing
This document summarizes a study on a receiver-based multicast protocol for wireless sensor networks. The protocol, called Receiver-Based Multicast (RBMulticast), removes the need for intermediate nodes to maintain multicast tree state information by embedding multicast member addresses in packet headers. This allows intermediate nodes to forward packets without storing state. The protocol was implemented and tested in the OPNET simulator. It requires less state than existing multicast protocols, making it well-suited for dynamic wireless sensor networks.
Efficient Of Multi-Hop Relay Algorithm for Efficient Broadcasting In MANETSijircee
The document proposes a multi-hop relay algorithm to improve broadcasting efficiency in mobile ad hoc networks (MANETs). It aims to optimize end-to-end delay, packet delivery ratio (PDR), and energy consumption during broadcasting. The algorithm uses source, broadcast, and relay queues at each node to facilitate multi-hop transmissions. It transmits packets using either single-hop, two-hop, or multi-hop relaying depending on the location of the destination node. The algorithm is shown to reduce average end-to-end delay by 3.37%, increase PDR by 1.36%, and reduce average energy consumption per node by 10% compared to previous techniques through simulation experiments.
A framework for routing performance analysis in delay tolerant networks with ...
1004.0152v1
1. Opportunistic Routing in Ad Hoc Networks:
How many relays should there be?
What rate should nodes use?
Joseph Blomer, Nihar Jindal
Dept. ECE, University of Minnesota, Minneapolis, MN, USA 55455,
Email: {blome015,nihar}@umn.edu
arXiv:1004.0152v1 [cs.IT] 1 Apr 2010
Abstract—Opportunistic routing is a multi-hop routing scheme algorithm, the key adjustable parameters are the transmission
which allows for selection of the best immediately available relay. probability and the transmission spectral efficiency.
In blind opportunistic routing protocols, where transmitters The transmission probability, denoted by p, determines the
blindly broadcast without knowledge of the surrounding nodes,
two fundamental design parameters are the node transmission proportion of transmitters to receivers in each slot. When p
probability and the transmission spectral efficiency. In this is large, there is a large amount of interference between the
paper these parameters are selected to maximize end-to-end nodes. This interference will cause only receivers close to
performance, characterized by the product of transmitter density, transmitters to be potential forwarders. When the transmission
hop distance and rate. Due to the intractability of the problem probability is low, there are fewer simultaneous transmissions
as stated, an approximation function is examined which proves
reasonably accurate. Our results show how the above design pa- and thus less interference and more available relays. Thus
rameters should be selected based on inherent system parameters longer hops are possible, but in fewer numbers. As a result, the
such as the path loss exponent and the noise level. trade-off with transmission probability is essentially between
many simultaneous short hops, or fewer long hops.
I. I NTRODUCTION
When the spectral efficiency is high, a large signal-to-
Ad hoc networks operate on the basis of multi-hop rout- interference ratio (SIR) is required to decode. Thus, only relays
ing, which allows information to be communicated across which are close to the transmitter are likely to decode. On the
the network over a series of hops. End-to-end performance other hand, a lower spectral efficiency allows nodes that are
depends critically on the quality of the multi-hop routes used, farther away to decode. Therefore, the trade-off with spectral
but choosing good routes in a dynamic network (e.g. one efficiency is between shorter hops at higher data rate or longer
where nodes are moving quickly) is a particularly difficult hops at a lower data rate.
task. Opportunistic routing (e.g [1] - [6]) is well suited to such The objective of this paper is determining the transmission
dynamic settings, as it can be performed with low overhead probability and spectral efficiency that optimally balance these
while also exploiting spatial diversity (in terms of fading and trade-offs. We study blind opportunistic routing in a spatial
topology). model, as in [1]. In this model, end-to-end performance is
In this paper we focus on a purely opportunistic routing characterized by the forward-rate-density, which is the prod-
protocol, in which nodes broadcast packets in a completely uct of average transmitter density, average hop distance and
blind manner (i.e. without any knowledge of surrounding transmission rate (spectral efficiency). This is a function of
nodes). More specifically, the protocol is described as follows: measured network properties (e.g. path-loss exponent) and
1) In each time slot, each node randomly decides, with adjustable parameters (spectral efficiency and transmission
some fixed probability, to either transmit or receive. probability). Our objective is to find the transmission prob-
2) A transmitting node will blindly broadcast a packet at ability and transmission spectral efficiency that maximize this
some fixed spectral efficiency, whereas receivers listen metric. Studying this quantity directly is intractable, however
for any transmission. we derive a reasonably accurate approximation and reinforce
3) All receiver nodes that successfully decode the packet the conclusions with Monte Carlo simulations.
will send an ACK back to the transmitting node during
an acknowledgement period. The ACK packets contain II. P RELIMINARIES
absolute geographic information about the RX location. A. Network Model
4) The transmitter selects the successful receiver which Consider an infinite set of transmit/receive nodes Φ dis-
offers the most progress towards the packet’s final des- tributed according to a homogeneous 2-D Poisson point
tination and sends a message to that node electing it to process (PPP) with density λ m−2 . We consider a slotted
become the next forwarder. transmission scheme. In each slot a node elects to become a
This protocol allows for the instantaneous choice of the transmitter with probability p, independent across users and
best next hop, at the cost of an acknowledgement period and slots. The set of locations of the transmitters (TX1, TX2,
with the requirement for geographical information. Within this ..) denoted Φt and the set of locations of the receivers Φr
2. Transmitter A. Forward progress density
Receiver
Succ. RX for node 1 We assume that the transmitter located at the origin has
a packet to be sent to a receiver a very large distance away
(e.g., fig. 1). Specifically, we assume the final destination is
to dest. located an infinite distance away along the x-axis. Thus, the
1
relay offering the most progress is the one with the maximum
forward prog.
x-coordinate amongst the set of receivers that successfully
2
decode TX0’s packet. The corresponding progress, for a given
network realization, is:
Fig. 1. Example network: TX node 1 has a message to be sent along dashed
D(Φr , Φt , β)
line. Among successful message receivers, RX node 2 offers the most forward max 1(Sj ≥ β|Φt ) |Xj | · cos θ (Xj ) (3)
progress and will forward the packet in the next slot. Xj ∈Φr
where 1(Sj ≥ β|Φt ) is the indicator function that the SIR at
RXj (at point Xj ) relative to TX0 (at the origin) is greater than
then form independent PPP’s of intensity λp and λ(1 − p) the threshold. The expectation of this function with respect to
respectively.
the node process and fading is d(p, β).
2
B. Channel Model d(p, β) EΦ,|h| D(Φr , Φt , β) (4)
This quantity is the expected progress (towards the destination)
We consider a path-loss model with exponent α > 2 and
made in each hop. The forward progress density f (p, β) then
Rayleigh fading coefficients hi,j from TX i to RX j. Denoting
is:
the signal transmitted by TXi (located at Xi ) as ui , the
received signal of RXj (at location Xj ) is given by: f (p, β) d(p, β)λp. (5)
Finally, the forward progress-rate-density function K(p, β) is
−α/2
Yj = hi,j |Xi − Xj | ui + z. (1) K(p, β) (λp) · E[D(Φr , Φt , β)] · log2 (1 + β)
i = f (p, β) · R(β). (6)
For the time being, consider the network is interference Assuming each node in the network wishes to send data to
limited, so thermal noise (z) is negligible. The case of a another node a distance L away, at most p · d(p, β)/L packets
channel with thermal noise is considered in Sec IV. can originate at each node in each slot [1]. Translating to
Assuming the transmit powers are all equal, the SIR (signal bits/sec/Hz, this means that the maximum end-to-end data rate
to interference ratio) from TX i to RX j is defined: (per node) is
|hi,j |2 |Xi − Xj |−α p · d(p, β) · log2 (1 + β)/L [bps/Hz]. (7)
Si,j 2 −α
. (2)
k=i |hk,j | |Xk − Xj | Thus, K(p, β) is directly proportional to end-to-end rate.
The quantity K(p, β), which is deterministic, is a function
We assume that all users transmit at rate equal to R(β) = of transmission probability p and SIR threshold β. We seek
log2 (1 + β); thus a communication is successful if and only the optimal values of β and p which maximize this product:
if the received SIR is larger than a threshold value β.
(p∗ , β ∗ ) = arg max K(p, β). (8)
p,β
III. P ROGRESS -R ATE P RODUCT A closed-form expression for K(p, β) cannot be found in
general, so we rely on an approximation which is developed
Although we are interested in the network-wide perfor- in the following section.
mance of the protocol, by the homogeneity of the PPP this
is statistically equivalent to the performance of any transmit- B. SIR Cell-Based Approximation
ter. Thus, without loss of generality we can focus on TX0 The basis of our approximation to K(p, β) is the concept of
located at the origin. From the perspective of TX0, all the an SIR cell [8], [9]. In the absence of fading, any RX within a
other TX nodes form a homogeneous PPP with intensity λp particular region (i.e., the SIR cell) around a TX can decode,
(by Slivnyaks Theorem [7], the distribution is unaffected by and the best forwarder is the RX in this region with the largest
conditioning on the presence of TX0). The transmitters and x-coordinate. Therefore, the forward progress is determined by
receivers are ordered by their distance to the origin i.e. TX1 the SIR cell – which is completely determined by the interferer
is closest to the origin, TX2 the next, etc. For the sake of locations and thus is a function only of the interferer process
simplicity, the SIR from TX0 to RXj is denoted Sj and is – and by the receiver locations (i.e., Φr ). To reach a tractable
given by Sj = S0,j . approximation for K(p, β), we remove the randomness in the
3. √
x v0 /2 − x
SIR cell and assume it is a deterministic region that is a
function of p and β, while retaining the randomness in Φr .
We consider the average size of the SIR cell. This quantity
√
is clearly defined in the absence of fading. On the other hand, v0
the SIR cell is not well defined with fading because the SIR
depends on independent fading RV’s (specific to each receiver
location) in addition to the interferer locations. However, we
can derive a quantity analogous to the SIR cell area, denoted
by v0 , by integrating the point-wise success probability over
all space. From [9], the success probability for a RX a distance
y from the TX is:
t
p0 (y) = PΦ [Sj ≥ β] Fig. 2. SIR cell is assumed to be a square V0 of side length v0 . The
√
2 probability that the forward progress is x is the probability there are no RX
−πλp|y|2 β α in the dark shaded area.
= exp . (9)
G(α)
Thus, v0 is given by: Thus, our approximation to the progress-rate-density is:
f (p, β) ≈ ˜ ˜
fsq (p, β) = dsq (p, β)(λp) (14)
G(α)
v0 = p0 (y)dy = . (10) ˜
˜ sq (p, β) = fsq (p, β) log2 (1 + β). (15)
y∈R2 λpβ α
2
K(p, β) ≈ K
where The optimal values then are the solution to the equation
α
G(α) = 2 2 (11) ∂ ∂ ˜
2Γ( α )Γ(1 − α ) Ksq (p, β) = 0. (16)
∂p ∂β
∞
and Γ(z) is the gamma function Γ(z) = 0 tz−1 e−t dz. Although there is no closed form solution to this equation,
We will then assume the SIR cell has area equal to its mean. the approximation nonetheless yields valuable insight. By rear-
We now approximate the SIR cell by a square centered on TX0 ranging the terms in (12), we can interpret the forward progress
√
with side v0 . In other words, we assume that all RX within approximation as the product of the maximum possible relay
this square are able to decode (ref. fig. 2). V0+ is the positive distance (i.e., half the side-length of the SIR cell) and a
half of that square with area v0 /2. Under these assumptions, fractional term that captures how much of the maximum is
the expected forward progress is: attained by the best receiver.
√
˜ v0 1 − e−c
˜ dsq (p, β) = 1− (17)
dsq (p, β) 2 c
max. relay dist. frac. of max.
= E max xj
+
Xj ∈V0 The value v0 is decreasing in p: as p increases, the amount
of interference between transmitters is increasing, giving each
= E E max xj # {Xj ∈ V0+ } = j transmitter a smaller expected SIR cell size. The value of c is
+
Xj ∈V0 also decreasing in p as a result of decreased v0 and smaller
∞ receiver density.
= E max xi # Xi ∈ V0+ =j × ˜
The value Ksq (p, β) can be written:
+
j=0 Xi ∈V0
˜
Ksq (p, β)
v0 j
v0 (λ · (1 − p) · 2 )
e −λ·(1−p)· 2 1 −2 1 − e−c
j! = log2 (1 + β) λpG(α)β α 1− (18)
∞ √ v0 j
2 c
v0 (λ · (1 − p) ·
v0 j 2 )
= · e−λ·(1−p)· 2 which lends the intuition that the end-to-end performance is
j=0
2 j+1 j! increasing with p until the 1 − 1−e fractional term becomes
−c
c
√ too small. When the value of c (expected potential forwarders)
v0 e−c − (1 − c)
= , (12) is greater than 3, this fractional term is greater than 2/3. When
2 c
p is large enough to cause c to go below 3, the performance
where #(·) gives the cardinality of a set and drops off sharply.
λ · (1 − p) · v0 (1 − p) G(α) IV. N UMERICAL R ESULTS
c = = . (13)
2 p 2β 2/α For numerical results, Monte-Carlo simulations were per-
Note that the value c is the expected number of receivers in formed. Locations of receivers and transmitters were realized
the half-square V0+ ; it is also equal to half the average number using the properties of the PPP (c.f. [10]). SIR was calculated
of successful outgoing transmissions from a TX as in [4]. at each receiver and the largest progress offered was averaged.
4. A. Accuracy, Path-loss and Fading
Fig. 3 shows the accuracy of the approximation of the 0.08
0dB
spatial density of progress (5), (14) for p and β. While the 0.07 5dB
7.5dB
approximation is not absolutely accurate, it does correctly
spatial density of progress
10dB
0.06
capture the dependence on p and β.
Fig. 4 shows the best p or β maximizing the progress- 0.05
rate-density (15) for a fixed β or p, respectively. Again, the 0.04
approximation helps to answer the essential question of what
parameter choices are optimal. 1 0.03
In Fig. 5 the jointly optimal (p, β) are plotted for different 0.02
values of the path loss exponent. Note that the optimal value
0.01
of p is essentially the same for α = 3 and 4, but that
the optimizing SIR threshold increases with the path loss 0
0 0.05 0.1 0.15 0.2 0.25
exponent. This increase is similar to [11], where the optimizing p transmission probability
SIR threshold is found for a slightly different, but related,
problem. Fig. 3. Spatial density of progress: approximation (thick curves) and
simulation for λ = 1, α = 3, varying SIR threshold β.
B. Sensitivity to parameter variation
Fig. 6 shows the normalized approximation of Eqn. (15) for
path loss α = 3 defined by
p* transmission prob.
0.15 Simulation
˜
Ksq (p, β) Approximation
˜
Ksq,norm (p, β) . (19)
˜
max(p,β) Ksq (p, β) 0.1
This figure shows how the performance decreases with differ- 0.05
ent values of p and β. Observe that there exist a wide range of −5 0 5
β SIR threshold dB
(p, β) pairs that are near optimal (within 90%). If there exists
4
a strong reason to choose a particular β (e.g., limited code Simulation
β* SIR dB
Approximation
rates & modulations), or a particular p (e.g., power cycling, 2
energy saving from different TX and RX powers), end-to-end
0
performance does not suffer as long as the other parameter is
appropriately chosen (to figs. 4, 6) −2
0.04 0.06 0.08 0.1 0.12 0.14 0.16
p transmission probability
C. Robustness to Noise
In order to simulate the effect of noise on the forward Fig. 4. Optimal p values giving best progress-rate-density for fixed values of
SIR β (top). Optimal β values giving maximum progress-rate for fixed values
progress, we modify the SIR (2) to include noise power σ 2 . p (bottom).
|hi,j |2 |Xi − Xj |−α
Si,j = 2 −α + σ 2
(20)
k=i |hk,j | |Xk − Xj |
The metric for comparison is the average SNR to a node 10
located at the average nearest-neighbor distance (dN N ). 8
simulated
approximation
−α α=4
E d2 N 2
N (λπ)α/2 6
SN RN N = = (21)
SIR threshold β (dB)
4
σ2 σ2
2 α=3
Fig. 7 shows the maximum forward-rate-density is decreasing
0
with increasing channel noise. Also, the number of potential
−2
forwarders is decreasing with increased channel noise.
Fig. 8 shows the effects of channel noise power on optimal −4
p and β. The value of p∗ is increasing and the value of β ∗ −6 α = 2.1
is decreasing with higher noise floor. The maximum possible −8 α = 2.1
spectral efficiency is expected to drop with increasing noise −10
0 0.05 0.1 0.15 0.2
power. As explored in IV-B, when β is fixed to some value p transmission probability
(in this case as a result of the noise floor), the transmission
probability can increase to compensate. Fig. 5. Optimal choice of p and β giving maximum progress-rate for fixed
α path-loss values.
1 Simulation results are similar for a non-fading environment.
5. V. C ONCLUSION
10 We studied the case of opportunistic routing in an ad hoc
0.3
8 wireless network with the goal of maximizing the product of
0.7
6
0.4 forward progress density and the rate of data transmission. We
0.5 developed an approximation using the concept of SIR cells
β SIR Threshold dB
4
and found for α = 3 the optimal spectral efficiency is near
0.8
0.9
0.6
0.9
2
0.5
1.3 bps/Hz and the optimal probability of transmission is near
9
0
0.06. The results give the intuition that having a low transmis-
0.4
−2
sion probability ensures a low amount of interference and a
0.3
−4
relatively high SIR threshold ensures only local transmissions
−6 are received.
0.2
−8
0.6 R EFERENCES
−10
0.05 0.1 0.15 0.2 0.25 0.3
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mation. hop ad hoc networks with adaptive antenna array systems.
[3] S. Biswas R. Morris, ExOR: Opportunistic Multi-Hop Routing for Wire-
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max progress−rate−density
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[5] E.S. Sousa, J.A. Silvester Optimum Transmission Ranges in a Direct-
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Radio Networks in the Presence of Fading IEEE Trans of Comm. Vol.
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0.02
[7] D. Stoyan, W. Kendall, and J. Mecke, Stochastic Geometry and Its
10 15 20 25 30 35 Applications. 2nd ed. New York: Wiley, 1996.
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2
[9] F. Baccelli, B. Blaszczyszyn, Stochastic Geometry and Wireless Networks,
1.5 Volume II: Applications Foundations and Trends in Networking, NOW
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10 15 20 25 30 35
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12 Dec. 2008
Fig. 7. Simulated best progress-rate-density achievable for varying SNR to
node at mean nearest-neighbor distance (λπ)α/2 /σ2
0.3 2
p*
β*
p transmission probability
β SIR Thresh. (dB)
0.2 0
0.1 −2
0 −4
5 10 15 20 25 30 35 40
SNR to node at avg. NN distance (dB)
Fig. 8. Optimal values of p, β for varying SNR to node at mean nearest-
neighbor distance (λπ)α/2 /σ2