This document proposes a new random access method called coherent contention resolution diversity slotted ALOHA (C-CRDSA) to improve the throughput of existing contention resolution diversity slotted ALOHA (CRDSA) for satellite Internet of Things systems. C-CRDSA accumulates replicated packets coherently at the receiver to increase the signal-to-noise ratio and enable better interference cancellation. It uses a sliding window approach to coherently accumulate potential virtual subframes across the access frame. Simulation results show C-CRDSA improves throughput, especially under heavy loads, by leveraging the diversity and coherence of transmitted packets.
Optical network is an emerging technology for data communication
inworldwide. The information is transmitted from the source to destination
through the fiber optics. All optical network (AON) provides good
transmission transparency, good expandability, large bandwidth, lower bit
error rate (BER), and high processing speed. Link failure and node failure
haveconsistently occurred in the traditional methods. In order to overcome
the above mentioned issues, this paper proposes a robust software defined
switching enabled fault localization framework (SDSFLF) to monitor the
node and link failure in an AON. In this work, a novel faulty node
localization (FNL) algorithm is exploited to locate the faulty node. Then, the
software defined faulty link detection (SDFLD) algorithm that addresses the
problem of link failure. The failures are localized in multi traffic stream
(MTS) and multi agent system (MAS). Thus, the throughput is improved in
SDSFLF compared than other existing methods like traditional routing and
wavelength assignment (RWA), simulated annealing (SA) algorithm, attackaware RWA (A-RWA) convex, longest path first (LPF) ordering, and
biggest source-destination node degree (BND) ordering. The performance of
the proposed algorithm is evaluated in terms of network load, wavelength
utilization, packet loss rate, and burst loss rate. Hence, proposed SDSFLF
assures that high performance is achieved than other traditional techniques.
This document summarizes a research paper that proposes a new cooperative channel load aware VoIP routing topology for 802.11 WLAN networks. It introduces the concept of cooperative channel transmitting technology for 802.11 WLAN networks and discusses some of the challenges in providing quality of service guarantees. It then presents a linear programming model and scheduling algorithm to implement cooperative channel transmissions while considering queue status and transitive node relationships to maximize throughput. Simulation results show that the proposed scheduling algorithm improves throughput and fairness compared to alternatives.
The document reviews different routing protocols for mobile ad hoc networks (MANETs). It begins with an introduction to MANETs and discusses some of their key characteristics including decentralized operation and dynamic topology. It then reviews several popular routing protocol categories for MANETs - flat, hierarchical, and location-based. Flat protocols like distance vector and link state are discussed as well as their limitations in dynamic MANET environments. The review covers over a dozen different specific routing protocols that have been proposed.
we find out various power aware and data packet rate control with-collision-avoidance (CSMA/CA)-based ad hoc wireless network communication. And identifies that CSMA
OPTIMUM NEIGHBORS FOR RESOURCECONSTRAINED MOBILE AD HOC NETWORKSijasuc
The document discusses investigating the optimum number of neighbors for mobile ad hoc networks (MANETs). It begins with background on MANETs and their characteristics. It then reviews related work that has looked at optimizing parameters like transmission range and node density. The paper aims to find the optimum number of neighbors under static, low mobility, and high mobility conditions using simulations. It analyzes performance metrics like end-to-end delay, throughput, energy consumption, and routing overhead to determine if there is an optimum number and if it differs based on mobility. The document outlines the investigation and summarizes key related work to provide context.
Optimum Neighbors for Resource-Constrained Mobile Ad Hoc Networksijasuc
This paper presents an investigation on the optimum number of neighbors for mobile ad hoc networks
(MANETs). The MANETs are self-configuring and self-organizing networks. In such a network, energyconstrained mobile nodes share limited bandwidth to send their packets to the destinations. The mobile nodes
have a limited transmission range and they rely on their neighbors to deliver their packets. Hence, the mobile
nodes must be associated with the required (i.e., optimum) number of neighbors. As the number of neighbors
is varied, a trade-off exists between the network connectivity and available bandwidth per mobile node. To
investigate this issue, we consider Dynamic Source Routing (DSR) as the routing protocol and IEEE 802.11
as the MAC layer protocol in this work. We consider both static and dynamic scenarios in this work. We
simulated the ad hoc networks via network simulator (NS-2) and the simulation results show that there exists
an optimum number of neighbors for the static case. We also show that mobility has a grave impact on the
performance of the MANETs in terms of network throughput, end-to-end delay, energy consumption, and
packet loss. Hence, we need to increase the number of neighbors under mobility conditions. However, there
is no global optimum number of neighbors for the mobility case.
OPTIMUM NEIGHBORS FOR RESOURCECONSTRAINED MOBILE AD HOC NETWORKSijasuc
Wireless networking has been an active research focus since the early days of the packet radio
network introduced by the Defense Advanced Research Project Agency (DARPA) [1]. Recent
developments in wireless devices have made laptop computers, personal digital assistants (PDA),
pagers, and cellular telephones portable. Now, users can carry these devices to any place at any
time. Hence, there is a need for a network that can be deployed at any place at any time without
any infrastructure support. In some cases, an infrastructure-based network is hard to build.
Networks used by the soldiers on the battlefield are worthwhile to mention here. In some cases,
infrastructures may not exist due to natural calamities such as cyclones, tsunami, and tornados.
Hence, there is always a need for setting up a temporary network among a group of users without
any pre-existing infrastructure and centralized administration. Mobile Ad hoc Networks
(MANETs) are considered suitable solutions for these kinds of temporary networks. MANETs
consist of a group of mobile nodes, which have limited battery and limited processing power.
MANETs are self-organizing and self-configuring networks and they can be deployed without any
infrastructure support. Numerous groundbreaking applications have been proposed based on
MANETs. These applications include disaster management, search and recovery, remote
International Journal of Ad hoc, Sensor & Ubiquitous Computing (IJASUC) Vol.12, No.2, April 2021
2
healthcare, tele-geoprocessing, education, traffic management, process control, and security [2].
These applications impose diversified design and performance constraints on the MANETs.
OPTIMUM NEIGHBORS FOR RESOURCECONSTRAINED MOBILE AD HOC NETWORKSijasuc
This paper presents an investigation on the optimum number of neighbors for mobile ad hoc networks
(MANETs). The MANETs are self-configuring and self-organizing networks. In such a network, energyconstrained mobile nodes share limited bandwidth to send their packets to the destinations. The mobile nodes
have a limited transmission range and they rely on their neighbors to deliver their packets. Hence, the mobile
nodes must be associated with the required (i.e., optimum) number of neighbors. As the number of neighbors
is varied, a trade-off exists between the network connectivity and available bandwidth per mobile node. To
investigate this issue, we consider Dynamic Source Routing (DSR) as the routing protocol and IEEE 802.11
as the MAC layer protocol in this work. We consider both static and dynamic scenarios in this work. We
simulated the ad hoc networks via network simulator (NS-2) and the simulation results show that there exists
an optimum number of neighbors for the static case. We also show that mobility has a grave impact on the
performance of the MANETs in terms of network throughput, end-to-end delay, energy consumption, and
packet loss. Hence, we need to increase the number of neighbors under mobility conditions. However, there
is no global optimum number of neighbors for the mobility case.
Optical network is an emerging technology for data communication
inworldwide. The information is transmitted from the source to destination
through the fiber optics. All optical network (AON) provides good
transmission transparency, good expandability, large bandwidth, lower bit
error rate (BER), and high processing speed. Link failure and node failure
haveconsistently occurred in the traditional methods. In order to overcome
the above mentioned issues, this paper proposes a robust software defined
switching enabled fault localization framework (SDSFLF) to monitor the
node and link failure in an AON. In this work, a novel faulty node
localization (FNL) algorithm is exploited to locate the faulty node. Then, the
software defined faulty link detection (SDFLD) algorithm that addresses the
problem of link failure. The failures are localized in multi traffic stream
(MTS) and multi agent system (MAS). Thus, the throughput is improved in
SDSFLF compared than other existing methods like traditional routing and
wavelength assignment (RWA), simulated annealing (SA) algorithm, attackaware RWA (A-RWA) convex, longest path first (LPF) ordering, and
biggest source-destination node degree (BND) ordering. The performance of
the proposed algorithm is evaluated in terms of network load, wavelength
utilization, packet loss rate, and burst loss rate. Hence, proposed SDSFLF
assures that high performance is achieved than other traditional techniques.
This document summarizes a research paper that proposes a new cooperative channel load aware VoIP routing topology for 802.11 WLAN networks. It introduces the concept of cooperative channel transmitting technology for 802.11 WLAN networks and discusses some of the challenges in providing quality of service guarantees. It then presents a linear programming model and scheduling algorithm to implement cooperative channel transmissions while considering queue status and transitive node relationships to maximize throughput. Simulation results show that the proposed scheduling algorithm improves throughput and fairness compared to alternatives.
The document reviews different routing protocols for mobile ad hoc networks (MANETs). It begins with an introduction to MANETs and discusses some of their key characteristics including decentralized operation and dynamic topology. It then reviews several popular routing protocol categories for MANETs - flat, hierarchical, and location-based. Flat protocols like distance vector and link state are discussed as well as their limitations in dynamic MANET environments. The review covers over a dozen different specific routing protocols that have been proposed.
we find out various power aware and data packet rate control with-collision-avoidance (CSMA/CA)-based ad hoc wireless network communication. And identifies that CSMA
OPTIMUM NEIGHBORS FOR RESOURCECONSTRAINED MOBILE AD HOC NETWORKSijasuc
The document discusses investigating the optimum number of neighbors for mobile ad hoc networks (MANETs). It begins with background on MANETs and their characteristics. It then reviews related work that has looked at optimizing parameters like transmission range and node density. The paper aims to find the optimum number of neighbors under static, low mobility, and high mobility conditions using simulations. It analyzes performance metrics like end-to-end delay, throughput, energy consumption, and routing overhead to determine if there is an optimum number and if it differs based on mobility. The document outlines the investigation and summarizes key related work to provide context.
Optimum Neighbors for Resource-Constrained Mobile Ad Hoc Networksijasuc
This paper presents an investigation on the optimum number of neighbors for mobile ad hoc networks
(MANETs). The MANETs are self-configuring and self-organizing networks. In such a network, energyconstrained mobile nodes share limited bandwidth to send their packets to the destinations. The mobile nodes
have a limited transmission range and they rely on their neighbors to deliver their packets. Hence, the mobile
nodes must be associated with the required (i.e., optimum) number of neighbors. As the number of neighbors
is varied, a trade-off exists between the network connectivity and available bandwidth per mobile node. To
investigate this issue, we consider Dynamic Source Routing (DSR) as the routing protocol and IEEE 802.11
as the MAC layer protocol in this work. We consider both static and dynamic scenarios in this work. We
simulated the ad hoc networks via network simulator (NS-2) and the simulation results show that there exists
an optimum number of neighbors for the static case. We also show that mobility has a grave impact on the
performance of the MANETs in terms of network throughput, end-to-end delay, energy consumption, and
packet loss. Hence, we need to increase the number of neighbors under mobility conditions. However, there
is no global optimum number of neighbors for the mobility case.
OPTIMUM NEIGHBORS FOR RESOURCECONSTRAINED MOBILE AD HOC NETWORKSijasuc
Wireless networking has been an active research focus since the early days of the packet radio
network introduced by the Defense Advanced Research Project Agency (DARPA) [1]. Recent
developments in wireless devices have made laptop computers, personal digital assistants (PDA),
pagers, and cellular telephones portable. Now, users can carry these devices to any place at any
time. Hence, there is a need for a network that can be deployed at any place at any time without
any infrastructure support. In some cases, an infrastructure-based network is hard to build.
Networks used by the soldiers on the battlefield are worthwhile to mention here. In some cases,
infrastructures may not exist due to natural calamities such as cyclones, tsunami, and tornados.
Hence, there is always a need for setting up a temporary network among a group of users without
any pre-existing infrastructure and centralized administration. Mobile Ad hoc Networks
(MANETs) are considered suitable solutions for these kinds of temporary networks. MANETs
consist of a group of mobile nodes, which have limited battery and limited processing power.
MANETs are self-organizing and self-configuring networks and they can be deployed without any
infrastructure support. Numerous groundbreaking applications have been proposed based on
MANETs. These applications include disaster management, search and recovery, remote
International Journal of Ad hoc, Sensor & Ubiquitous Computing (IJASUC) Vol.12, No.2, April 2021
2
healthcare, tele-geoprocessing, education, traffic management, process control, and security [2].
These applications impose diversified design and performance constraints on the MANETs.
OPTIMUM NEIGHBORS FOR RESOURCECONSTRAINED MOBILE AD HOC NETWORKSijasuc
This paper presents an investigation on the optimum number of neighbors for mobile ad hoc networks
(MANETs). The MANETs are self-configuring and self-organizing networks. In such a network, energyconstrained mobile nodes share limited bandwidth to send their packets to the destinations. The mobile nodes
have a limited transmission range and they rely on their neighbors to deliver their packets. Hence, the mobile
nodes must be associated with the required (i.e., optimum) number of neighbors. As the number of neighbors
is varied, a trade-off exists between the network connectivity and available bandwidth per mobile node. To
investigate this issue, we consider Dynamic Source Routing (DSR) as the routing protocol and IEEE 802.11
as the MAC layer protocol in this work. We consider both static and dynamic scenarios in this work. We
simulated the ad hoc networks via network simulator (NS-2) and the simulation results show that there exists
an optimum number of neighbors for the static case. We also show that mobility has a grave impact on the
performance of the MANETs in terms of network throughput, end-to-end delay, energy consumption, and
packet loss. Hence, we need to increase the number of neighbors under mobility conditions. However, there
is no global optimum number of neighbors for the mobility case.
Throughput Maximization using Spatial Reusability in Multi Hop Wireless Networkijtsrd
Energy is a valuable resource in wireless networks. For many multi hop networking scenarios, nodes require power for performing their operation, so requiring capable power management to make certain connectivity across the network. Though when wireless networks are attached outside power source due to obstruction between lively links the network may demand excessive energy per unit time Power due to this the overall performance is reduced. Since network life time or network capacity is depend on the power efficiency, many efforts to study energy efficient networks in the wireless network community. In multi hop wireless networks well organized routing algorithms are significant for network performance. We dispute that by carefully considering spatial reusability of the wireless communication media, we can reduce the overhead in multi hop wireless networks. To support our argument, propose Broadcast Tree Construction BTC and compare them with existing routing and multi path routing protocols, respectively. Our estimate outcome shows that proposed protocols significantly improve the end to end throughput compared with existing protocols. We also introduce the sleep scheduling approach for energy consumption and hybrid cryptography for security of data that can be prevent the data leakage and jammer attacks. Twinkal P. Dudhagawali | Prof. L. K. Gautam | Prof. V. P. Vaidya ""Throughput Maximization using Spatial Reusability in Multi Hop Wireless Network"" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-3 , April 2019, URL: https://www.ijtsrd.com/papers/ijtsrd23489.pdf
Paper URL: https://www.ijtsrd.com/engineering/information-technology/23489/throughput-maximization-using-spatial-reusability-in-multi-hop-wireless-network/twinkal-p-dudhagawali
Energy Behavior in Ad Hoc Network Minimizing the Number of Hops and Maintaini...CSCJournals
Wireless ad-hoc mesh network is a special kind of network, where all of the nodes move in time. The topology of the network changes as the nodes are in the proximity of each other. Ad-hoc networks are generally self-configuring no stable infrastructure takes a place. In this network, each node should help relaying packets of neighboring nodes using multi-hop routing mechanism. This mechanism is needed to reach far destination nodes to solve problem of dead communication. This multiple traffic "hops" within a wireless mesh network caused dilemma. Wireless mesh network that contain multiple hops become increasingly vulnerable to problems such as energy degradation and rapid increasing of overhead packets. This paper provides a generic routing framework that balances energy efficient broadcast schemes in Wireless (Ad-Hoc) Mesh Network and maintaining connectivity of nodes (mobile terminals). Typically, each node’s activities will consume energy, either for sending packets, receiving or preparing/processing packets. Number of hops, distance of nodes, and size of packet will determine the consumption of energy. The framework is based on the principle that additional relay nodes with appropriate energy and routing metric between source and final destination significantly reduces the energy consumption necessary to deliver packets in Wireless (Ad-Hoc) Mesh Network while keep the connectivity of dynamic nodes. Using the framework, the average network connectivity is kept 18% higher and the lifetime of network lasting more than 2.38% compared with network with Link State Routing mechanism. The simulation notes that the end-to-end delay may increase rapidly if relay nodes are more than five.
Dynamic cluster based adaptive gateway discovery mechanisms in an integrated ...IAEME Publication
This document discusses dynamic cluster-based adaptive gateway discovery mechanisms for integrating mobile ad hoc networks (MANETs) with the Internet. It begins by introducing the problem and outlines existing solutions. It then proposes a new architecture using dynamic clusters and mobile gateways. Key points of the proposed approach include dynamically adjusting the TTL value and periodicity of gateway advertisements based on network characteristics. The paper evaluates the approach through simulations in NS-2, finding it increases reliability and performance metrics like delivery ratio and delay. In conclusion, dynamic cluster-based gateways help provide reliable Internet access for MANET nodes with varying mobility.
CROSS LAYER DESIGN APPROACH FOR EFFICIENT DATA DELIVERY BASED ON IEEE 802.11P...pijans
Intelligent Transportation Systems (ITS) have been one of the promising technology that has a great interest attention from many researchers over the world. Vehicular Ad-hoc Network (VANET) communications environment as a part of ITS opens the way for a wide range of applications such as safety applications, mobility and connectivity for both driver and passengers to exploit the transport systems in a smoothly, efficiently and safer way. Several challenging tasks facing adopting VANET functionality for ITS such as modelling of wireless transmission and routing issues. These research issues have become more critical due to the high mobility of vehicles nodes (transmitters and receivers) and unexpected network topology due to the high speed of nodes. In fact, modelling radio propagation channel in VANET environment which considers as one of a stringent communications environment is a challenging task. The selection of a suitable transmission model plays a key role in the routing decisions for VANET. Different propagation models allow calculating the Received Signal Strength (RSS) based on key environmental properties such as the distance between transmitter vehicle and a receiver vehicle, the gain and antenna height of transmitter and a receiver vehicles. Hence, it is useful to calculate RSS and SNR values for a specific propagation model and then these values can be used later for routing decision in order to find the best path with high SNR. This paper evaluates the performance of different transmission models (freespace, two-ray and log-normal) in terms of Receive Signal Strength (RSS). In addition, the performance of such wireless transmission models for vehicular communication in terms of PDR, throughput and delay is evaluated by applying the proposed cross layer routing approach based on IEEE 802.11p. By using MATLAB, the obtained results confirm the best packet delivery ratio for our proposed approach, where it indicates poor quality of DSSS PHY with high number vehicles. The minimum delay achieved when traffic density is decreased.
CROSS LAYER DESIGN APPROACH FOR EFFICIENT DATA DELIVERY BASED ON IEEE 802.11P...pijans
Intelligent Transportation Systems (ITS) have been one of the promising technology that has a great
interest attention from many researchers over the world. Vehicular Ad-hoc Network (VANET)
communications environment as a part of ITS opens the way for a wide range of applications such as safety
applications, mobility and connectivity for both driver and passengers to exploit the transport systems in a
smoothly, efficiently and safer way. Several challenging tasks facing adopting VANET functionality for ITS
such as modelling of wireless transmission and routing issues. These research issues have become more
critical due to the high mobility of vehicles nodes (transmitters and receivers) and unexpected network
topology due to the high speed of nodes. In fact, modelling radio propagation channel in VANET
environment which considers as one of a stringent communications environment is a challenging task. The
selection of a suitable transmission model plays a key role in the routing decisions for VANET. Different
propagation models allow calculating the Received Signal Strength (RSS) based on key environmental
properties such as the distance between transmitter vehicle and a receiver vehicle, the gain and antenna
height of transmitter and a receiver vehicles. Hence, it is useful to calculate RSS and SNR values for a
specific propagation model and then these values can be used later for routing decision in order to find the
best path with high SNR. This paper evaluates the performance of different transmission models (free-
space, two-ray and log-normal) in terms of Receive Signal Strength (RSS). In addition, the performance of
such wireless transmission models for vehicular communication in terms of PDR, throughput and delay is
evaluated by applying the proposed cross layer routing approach based on IEEE 802.11p. By using
MATLAB, the obtained results confirm the best packet delivery ratio for our proposed approach, where it
indicates poor quality of DSSS PHY with high number vehicles. The minimum delay achieved when traffic
density is decreased
A QoS Based MAC Protocol For Wireless Ad-hoc NetworkIJNSA Journal
Multimedia communication over wireless Ad-hoc networks has become the driving technology for many of the important applications, experiencing dramatic market growth and promising revolutionary experiences in personal communication, gaming, entertainment, military, security, environment monitoring, and more. The advances in wireless communications and growth of real-time applications have necessitated the development of wireless networks that can support high Quality of Service (QoS) and power control. A node in an ad hoc network is normally battery operated which poses a huge constraint on the power consumption of such a node. Hence, designing a power efficient MAC protocol for ad hoc wireless networks is a major challenge. In this paper, we propose a CDMA based power controlled medium access protocol for mobile and ad hoc network (MNA). The protocol conserves power and provides QoS guarantees for multimedia traffics. In that network one of the fundamental challenger in MANETs is how to increase the overall network throughputs well as reading the delay while maintaining how energy consumption for packet processing in communication. simulation results shows that the performance of the protocol with increase in traffic while QoS is better in terms of Energy consumption, throughput, & communication delay than existing protocol.
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CPCRT: Crosslayered and Power Conserved Routing Topology for congestion Cont...IOSR Journals
The document describes a proposed Crosslayered and Power Conserved Routing Topology (CPCRT) for congestion control in mobile ad hoc networks. The CPCRT aims to improve transmission performance by distinguishing between packet loss due to link failure versus other causes, while also conserving power used for packet transmission. It builds upon an earlier Crosslayered Routing Topology (CRT) approach by incorporating power conservation. The CPCRT is intended to identify the root cause of packet loss, avoid unnecessary congestion handling from link failures, allow congestion handling at specific high-traffic nodes rather than all nodes, and optimize resource and power usage for packet routing in mobile ad hoc networks.
An investigation-on-efficient-spreading-codes-for-transmitter-based-technique...Cemal Ardil
This document summarizes research on efficient spreading codes for transmitter-based techniques to mitigate interference in time division duplex code division multiple access (TDD/CDMA) downlink systems. It investigates bitwise and blockwise multiuser transmission schemes that transfer complexity to the transmitter. Different spreading codes are evaluated based on correlation properties to determine suitability for techniques like precoding, pre-rake, and rake diversity. Performance is measured by bit error rate with varying numbers of users to identify the most efficient codes for interference mitigation.
Congestion in Wireless Sensor Networks has negative impact on the Quality of Service.
Congestion effects the performance metrics, namely throughput and per-packet energy
consumption, network lifetime and packet delivery ratio. Reducing congestion allows better
utilization of the network resources and thus enhances the Quality of Service metrics of the
network. Traffic Aware Dynamic Routing to Alleviate Congestion in Wireless Sensor Networks
reduces congestion by considering one hop neighbor routing in the network. This paper
proposed an algorithm for Quality of Service Based Traffic-Aware Data forwarding for
congestion control in wireless sensor networks based on two hop neighbor information. On
detection of congestion, the algorithm forwards data packets around the congestion areas by
spreading the excessive packets through multiple paths. The path with light load or under
loaded nodes is efficiently utilized whenever congestion occurs. The main aspect of the
algorithm is to build path to the destination using two independent potential fields depth and
queue length. Queue length field solves the traffic-aware problem. Depth field creates a
backbone to forward packets to the sink. Both fields are combined to yield a hybrid potential
field to make dynamic decision for data forwarding. Network Simulator used for simulating the
algorithm is NS2. The proposed algorithm performs better.
TTACCA: TWO-HOP BASED TRAFFIC AWARE CONGESTION CONTROL ALGORITHM FOR WIRELESS...cscpconf
Congestion in Wireless Sensor Networks has negative impact on the Quality of Service.
Congestion effects the performance metrics, namely throughput and per-packet energy
consumption, network lifetime and packet delivery ratio. Reducing congestion allows better
utilization of the network resources and thus enhances the Quality of Service metrics of the
network. Traffic Aware Dynamic Routing to Alleviate Congestion in Wireless Sensor Networks
reduces congestion by considering one hop neighbor routing in the network. This paper
proposed an algorithm for Quality of Service Based Traffic-Aware Data forwarding for
congestion control in wireless sensor networks based on two hop neighbor information. On
detection of congestion, the algorithm forwards data packets around the congestion areas by
spreading the excessive packets through multiple paths. The path with light load or under
loaded nodes is efficiently utilized whenever congestion occurs. The main aspect of the
algorithm is to build path to the destination using two independent potential fields depth and
queue length. Queue length field solves the traffic-aware problem. Depth field creates a
backbone to forward packets to the sink. Both fields are combined to yield a hybrid potential
field to make dynamic decision for data forwarding. Network Simulator used for simulating the
algorithm is NS2. The proposed algorithm performs better.
Priority based bandwidth allocation in wireless sensor networksIJCNCJournal
Most of the sensor network applications need real time communication and the need for deadline aware real time communication is becoming eminent in these applications. These applications have different dead line requirements also. The real time applications of wireless sensor networks are bandwidth sensitive and need higher share of bandwidth for higher priority data to meet the dead line requirements. In this paper we focus on the MAC layer modifications to meet the real time requirements of different priority data.Bandwidth partitioning among different priority transmissions is implemented through MAC layer modifications. The MAC layer implements a queuing model that supports lower transfer rate for lower
priority packets and higher transfer rate for real
time packets with higher priority, minimizing the end to
end delay. The performance of the algorithm is evaluated with varying node distribution
.
PERFORMANCE ANALYSIS OF THE LINK-ADAPTIVE COOPERATIVE AMPLIFY-AND-FORWARD REL...IJCNCJournal
This paper analyzes the performance of cooperative amplify-and-forward (CAF) relay networks that
employ adaptive M-ary quadrature amplitude modulation (M-QAM)/M-ary phase shift keying (M-PSK)
digital modulation techniques in Nakagami-m fading channel. In particular, we present and compared the
analysis of CAF relay networks with different cooperative diversity and opportunistic routing strategies
such as regular Maximal Ratio Combining (MRC), Selection Diversity Combining (SDC), Opportunistic
Relay Selection with Maximal Ratio Combining (ORS-MRC) and Opportunistic Relay Selection with
Selection Diversity Combining (ORS-SDC). We advocate a simple yet unified numerical approach based on
the marginal moment generating function (MGF) of the total received SNR to compute the average symbol
error rate (ASER), mean achievable spectral efficiency, and outage probability performance metrics.
The document discusses several topics related to mobile networks and context-aware computing. It describes research presented at a conference on the following topics: evolution of cellular standards and the telecom market; mobility metrics and routing in mobile ad hoc networks; wireless web services using mobile agents; modeling and reasoning about context; and adapting applications and services based on user context. It also summarizes research on topics like vertical handoff, quality of service, location-based services, and context-aware recommendation systems.
The document proposes a Crosslayered and Power Conserved Routing Topology (CPCRT) for congestion control in mobile ad hoc networks. CPCRT aims to distinguish between packet loss due to link failure versus other causes like congestion. It takes a cross-layer approach using information from the physical, MAC, and application layers. The proposed method also aims to conserve power during packet transmission by adjusting transmission power levels based on received signal strength. Simulation results show that CPCRT can better utilize resources and conserve power during congestion control compared to other approaches.
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.
Resource Dependent Radio Allocation For Battlefield Communications - A Data M...IJERA Editor
Network Enabled Capability (NEC) and the Land Open Systems Architecture (LOSA) are novel approaches to enable interoperability between a heterogeneous collection of assets in the battlefield. These paradigms utilise an underlying network for cooperation between deployed battlefield equipment. NEC and LOSA have great potential to transform military communications and enhance integrated survivability as well as situational awareness, but the Achilles’ heel of NEC and LOSA is the wireless spectrum over which they must communicate. A noisy and dynamic battlefield wireless spectrum as well as an array of heterogeneous wireless communications equipment handling multiple types of data with different Quality of Service (QoS) requirements requires a system which manages and allocates these communication resources effectively. This paper presents the High Availability Wireless Communications (HAWC) system, a hardware agnostic communications controller middleware to manage any combination of existing and future multiband wireless resources. The system utilises a vehicle’s data model to gather information about available radio resources and enable LOSA by meeting communications data requirements and delivering appropriate QoS to the appropriate traffic in a fleet of vehicles. The functionality of the system is verified by using behavioural simulation on a virtual battlefield.
GLOBAL FRONTRUNNER ROUTING ALGORITHM (GFRA) FOR V2V COMMUNICATION IN VANETS cscpconf
VANET (Vehicular Ad hoc NETwork) is the emerging research area that making the phrase
“Network on Wheel” true. In this new age network the basic WLAN (IEEE 802.11) standard is
used. As the necessity of such network increases the implementation challenges are being taken
into account. They are broadcasting, routing, priority scheduling and security and privacy. In
this paper the routing is considered as the research factor. A proposal for routing with
frequently changing topology to avoid disconnection of network on road and for the routing
among overlapping networks in flyovers with multiple ramps and stack to avoid wrong
messaging is given.
GLOBAL FRONTRUNNER ROUTING ALGORITHM (GFRA) FOR V2V COMMUNICATION IN VANETS cscpconf
This document proposes a Global Frontrunner Routing Algorithm (GFRA) to address routing challenges in Vehicular Ad Hoc Networks (VANETs). GFRA aims to minimize transmission delays by reducing the number of hops needed to route emergency messages between vehicles. It determines the distance and direction to the destination vehicle, and if it is over 1000m away, forwards the message to the nearest "frontrunner" vehicle along the direction of travel. This frontrunner or subsequent frontrunners will continue forwarding the message until it reaches the destination vehicle. Simulation results will evaluate GFRA's performance in reducing delays compared to multi-hop routing protocols for VANETs. The algorithm
MASSIVE MACHINE TYPE COMMUNICATION TOWARDS 6G.pdfYAAKOVSOLOMON1
This white paper explores key research directions for machine type communication (MTC) towards 6G networks by 2030. It discusses the main societal drivers of MTC, such as autonomous mobility and smart manufacturing. Representative MTC use cases are presented across various industries. Emerging MTC services are expected to have highly diverse requirements in terms of performance metrics like reliability, latency, energy efficiency, and scalability. The white paper investigates potential enabling technologies for building a holistic MTC network architecture in 6G that can efficiently support both massive and critical MTC services.
Throughput Maximization using Spatial Reusability in Multi Hop Wireless Networkijtsrd
Energy is a valuable resource in wireless networks. For many multi hop networking scenarios, nodes require power for performing their operation, so requiring capable power management to make certain connectivity across the network. Though when wireless networks are attached outside power source due to obstruction between lively links the network may demand excessive energy per unit time Power due to this the overall performance is reduced. Since network life time or network capacity is depend on the power efficiency, many efforts to study energy efficient networks in the wireless network community. In multi hop wireless networks well organized routing algorithms are significant for network performance. We dispute that by carefully considering spatial reusability of the wireless communication media, we can reduce the overhead in multi hop wireless networks. To support our argument, propose Broadcast Tree Construction BTC and compare them with existing routing and multi path routing protocols, respectively. Our estimate outcome shows that proposed protocols significantly improve the end to end throughput compared with existing protocols. We also introduce the sleep scheduling approach for energy consumption and hybrid cryptography for security of data that can be prevent the data leakage and jammer attacks. Twinkal P. Dudhagawali | Prof. L. K. Gautam | Prof. V. P. Vaidya ""Throughput Maximization using Spatial Reusability in Multi Hop Wireless Network"" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-3 , April 2019, URL: https://www.ijtsrd.com/papers/ijtsrd23489.pdf
Paper URL: https://www.ijtsrd.com/engineering/information-technology/23489/throughput-maximization-using-spatial-reusability-in-multi-hop-wireless-network/twinkal-p-dudhagawali
Energy Behavior in Ad Hoc Network Minimizing the Number of Hops and Maintaini...CSCJournals
Wireless ad-hoc mesh network is a special kind of network, where all of the nodes move in time. The topology of the network changes as the nodes are in the proximity of each other. Ad-hoc networks are generally self-configuring no stable infrastructure takes a place. In this network, each node should help relaying packets of neighboring nodes using multi-hop routing mechanism. This mechanism is needed to reach far destination nodes to solve problem of dead communication. This multiple traffic "hops" within a wireless mesh network caused dilemma. Wireless mesh network that contain multiple hops become increasingly vulnerable to problems such as energy degradation and rapid increasing of overhead packets. This paper provides a generic routing framework that balances energy efficient broadcast schemes in Wireless (Ad-Hoc) Mesh Network and maintaining connectivity of nodes (mobile terminals). Typically, each node’s activities will consume energy, either for sending packets, receiving or preparing/processing packets. Number of hops, distance of nodes, and size of packet will determine the consumption of energy. The framework is based on the principle that additional relay nodes with appropriate energy and routing metric between source and final destination significantly reduces the energy consumption necessary to deliver packets in Wireless (Ad-Hoc) Mesh Network while keep the connectivity of dynamic nodes. Using the framework, the average network connectivity is kept 18% higher and the lifetime of network lasting more than 2.38% compared with network with Link State Routing mechanism. The simulation notes that the end-to-end delay may increase rapidly if relay nodes are more than five.
Dynamic cluster based adaptive gateway discovery mechanisms in an integrated ...IAEME Publication
This document discusses dynamic cluster-based adaptive gateway discovery mechanisms for integrating mobile ad hoc networks (MANETs) with the Internet. It begins by introducing the problem and outlines existing solutions. It then proposes a new architecture using dynamic clusters and mobile gateways. Key points of the proposed approach include dynamically adjusting the TTL value and periodicity of gateway advertisements based on network characteristics. The paper evaluates the approach through simulations in NS-2, finding it increases reliability and performance metrics like delivery ratio and delay. In conclusion, dynamic cluster-based gateways help provide reliable Internet access for MANET nodes with varying mobility.
CROSS LAYER DESIGN APPROACH FOR EFFICIENT DATA DELIVERY BASED ON IEEE 802.11P...pijans
Intelligent Transportation Systems (ITS) have been one of the promising technology that has a great interest attention from many researchers over the world. Vehicular Ad-hoc Network (VANET) communications environment as a part of ITS opens the way for a wide range of applications such as safety applications, mobility and connectivity for both driver and passengers to exploit the transport systems in a smoothly, efficiently and safer way. Several challenging tasks facing adopting VANET functionality for ITS such as modelling of wireless transmission and routing issues. These research issues have become more critical due to the high mobility of vehicles nodes (transmitters and receivers) and unexpected network topology due to the high speed of nodes. In fact, modelling radio propagation channel in VANET environment which considers as one of a stringent communications environment is a challenging task. The selection of a suitable transmission model plays a key role in the routing decisions for VANET. Different propagation models allow calculating the Received Signal Strength (RSS) based on key environmental properties such as the distance between transmitter vehicle and a receiver vehicle, the gain and antenna height of transmitter and a receiver vehicles. Hence, it is useful to calculate RSS and SNR values for a specific propagation model and then these values can be used later for routing decision in order to find the best path with high SNR. This paper evaluates the performance of different transmission models (freespace, two-ray and log-normal) in terms of Receive Signal Strength (RSS). In addition, the performance of such wireless transmission models for vehicular communication in terms of PDR, throughput and delay is evaluated by applying the proposed cross layer routing approach based on IEEE 802.11p. By using MATLAB, the obtained results confirm the best packet delivery ratio for our proposed approach, where it indicates poor quality of DSSS PHY with high number vehicles. The minimum delay achieved when traffic density is decreased.
CROSS LAYER DESIGN APPROACH FOR EFFICIENT DATA DELIVERY BASED ON IEEE 802.11P...pijans
Intelligent Transportation Systems (ITS) have been one of the promising technology that has a great
interest attention from many researchers over the world. Vehicular Ad-hoc Network (VANET)
communications environment as a part of ITS opens the way for a wide range of applications such as safety
applications, mobility and connectivity for both driver and passengers to exploit the transport systems in a
smoothly, efficiently and safer way. Several challenging tasks facing adopting VANET functionality for ITS
such as modelling of wireless transmission and routing issues. These research issues have become more
critical due to the high mobility of vehicles nodes (transmitters and receivers) and unexpected network
topology due to the high speed of nodes. In fact, modelling radio propagation channel in VANET
environment which considers as one of a stringent communications environment is a challenging task. The
selection of a suitable transmission model plays a key role in the routing decisions for VANET. Different
propagation models allow calculating the Received Signal Strength (RSS) based on key environmental
properties such as the distance between transmitter vehicle and a receiver vehicle, the gain and antenna
height of transmitter and a receiver vehicles. Hence, it is useful to calculate RSS and SNR values for a
specific propagation model and then these values can be used later for routing decision in order to find the
best path with high SNR. This paper evaluates the performance of different transmission models (free-
space, two-ray and log-normal) in terms of Receive Signal Strength (RSS). In addition, the performance of
such wireless transmission models for vehicular communication in terms of PDR, throughput and delay is
evaluated by applying the proposed cross layer routing approach based on IEEE 802.11p. By using
MATLAB, the obtained results confirm the best packet delivery ratio for our proposed approach, where it
indicates poor quality of DSSS PHY with high number vehicles. The minimum delay achieved when traffic
density is decreased
A QoS Based MAC Protocol For Wireless Ad-hoc NetworkIJNSA Journal
Multimedia communication over wireless Ad-hoc networks has become the driving technology for many of the important applications, experiencing dramatic market growth and promising revolutionary experiences in personal communication, gaming, entertainment, military, security, environment monitoring, and more. The advances in wireless communications and growth of real-time applications have necessitated the development of wireless networks that can support high Quality of Service (QoS) and power control. A node in an ad hoc network is normally battery operated which poses a huge constraint on the power consumption of such a node. Hence, designing a power efficient MAC protocol for ad hoc wireless networks is a major challenge. In this paper, we propose a CDMA based power controlled medium access protocol for mobile and ad hoc network (MNA). The protocol conserves power and provides QoS guarantees for multimedia traffics. In that network one of the fundamental challenger in MANETs is how to increase the overall network throughputs well as reading the delay while maintaining how energy consumption for packet processing in communication. simulation results shows that the performance of the protocol with increase in traffic while QoS is better in terms of Energy consumption, throughput, & communication delay than existing protocol.
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CPCRT: Crosslayered and Power Conserved Routing Topology for congestion Cont...IOSR Journals
The document describes a proposed Crosslayered and Power Conserved Routing Topology (CPCRT) for congestion control in mobile ad hoc networks. The CPCRT aims to improve transmission performance by distinguishing between packet loss due to link failure versus other causes, while also conserving power used for packet transmission. It builds upon an earlier Crosslayered Routing Topology (CRT) approach by incorporating power conservation. The CPCRT is intended to identify the root cause of packet loss, avoid unnecessary congestion handling from link failures, allow congestion handling at specific high-traffic nodes rather than all nodes, and optimize resource and power usage for packet routing in mobile ad hoc networks.
An investigation-on-efficient-spreading-codes-for-transmitter-based-technique...Cemal Ardil
This document summarizes research on efficient spreading codes for transmitter-based techniques to mitigate interference in time division duplex code division multiple access (TDD/CDMA) downlink systems. It investigates bitwise and blockwise multiuser transmission schemes that transfer complexity to the transmitter. Different spreading codes are evaluated based on correlation properties to determine suitability for techniques like precoding, pre-rake, and rake diversity. Performance is measured by bit error rate with varying numbers of users to identify the most efficient codes for interference mitigation.
Congestion in Wireless Sensor Networks has negative impact on the Quality of Service.
Congestion effects the performance metrics, namely throughput and per-packet energy
consumption, network lifetime and packet delivery ratio. Reducing congestion allows better
utilization of the network resources and thus enhances the Quality of Service metrics of the
network. Traffic Aware Dynamic Routing to Alleviate Congestion in Wireless Sensor Networks
reduces congestion by considering one hop neighbor routing in the network. This paper
proposed an algorithm for Quality of Service Based Traffic-Aware Data forwarding for
congestion control in wireless sensor networks based on two hop neighbor information. On
detection of congestion, the algorithm forwards data packets around the congestion areas by
spreading the excessive packets through multiple paths. The path with light load or under
loaded nodes is efficiently utilized whenever congestion occurs. The main aspect of the
algorithm is to build path to the destination using two independent potential fields depth and
queue length. Queue length field solves the traffic-aware problem. Depth field creates a
backbone to forward packets to the sink. Both fields are combined to yield a hybrid potential
field to make dynamic decision for data forwarding. Network Simulator used for simulating the
algorithm is NS2. The proposed algorithm performs better.
TTACCA: TWO-HOP BASED TRAFFIC AWARE CONGESTION CONTROL ALGORITHM FOR WIRELESS...cscpconf
Congestion in Wireless Sensor Networks has negative impact on the Quality of Service.
Congestion effects the performance metrics, namely throughput and per-packet energy
consumption, network lifetime and packet delivery ratio. Reducing congestion allows better
utilization of the network resources and thus enhances the Quality of Service metrics of the
network. Traffic Aware Dynamic Routing to Alleviate Congestion in Wireless Sensor Networks
reduces congestion by considering one hop neighbor routing in the network. This paper
proposed an algorithm for Quality of Service Based Traffic-Aware Data forwarding for
congestion control in wireless sensor networks based on two hop neighbor information. On
detection of congestion, the algorithm forwards data packets around the congestion areas by
spreading the excessive packets through multiple paths. The path with light load or under
loaded nodes is efficiently utilized whenever congestion occurs. The main aspect of the
algorithm is to build path to the destination using two independent potential fields depth and
queue length. Queue length field solves the traffic-aware problem. Depth field creates a
backbone to forward packets to the sink. Both fields are combined to yield a hybrid potential
field to make dynamic decision for data forwarding. Network Simulator used for simulating the
algorithm is NS2. The proposed algorithm performs better.
Priority based bandwidth allocation in wireless sensor networksIJCNCJournal
Most of the sensor network applications need real time communication and the need for deadline aware real time communication is becoming eminent in these applications. These applications have different dead line requirements also. The real time applications of wireless sensor networks are bandwidth sensitive and need higher share of bandwidth for higher priority data to meet the dead line requirements. In this paper we focus on the MAC layer modifications to meet the real time requirements of different priority data.Bandwidth partitioning among different priority transmissions is implemented through MAC layer modifications. The MAC layer implements a queuing model that supports lower transfer rate for lower
priority packets and higher transfer rate for real
time packets with higher priority, minimizing the end to
end delay. The performance of the algorithm is evaluated with varying node distribution
.
PERFORMANCE ANALYSIS OF THE LINK-ADAPTIVE COOPERATIVE AMPLIFY-AND-FORWARD REL...IJCNCJournal
This paper analyzes the performance of cooperative amplify-and-forward (CAF) relay networks that
employ adaptive M-ary quadrature amplitude modulation (M-QAM)/M-ary phase shift keying (M-PSK)
digital modulation techniques in Nakagami-m fading channel. In particular, we present and compared the
analysis of CAF relay networks with different cooperative diversity and opportunistic routing strategies
such as regular Maximal Ratio Combining (MRC), Selection Diversity Combining (SDC), Opportunistic
Relay Selection with Maximal Ratio Combining (ORS-MRC) and Opportunistic Relay Selection with
Selection Diversity Combining (ORS-SDC). We advocate a simple yet unified numerical approach based on
the marginal moment generating function (MGF) of the total received SNR to compute the average symbol
error rate (ASER), mean achievable spectral efficiency, and outage probability performance metrics.
The document discusses several topics related to mobile networks and context-aware computing. It describes research presented at a conference on the following topics: evolution of cellular standards and the telecom market; mobility metrics and routing in mobile ad hoc networks; wireless web services using mobile agents; modeling and reasoning about context; and adapting applications and services based on user context. It also summarizes research on topics like vertical handoff, quality of service, location-based services, and context-aware recommendation systems.
The document proposes a Crosslayered and Power Conserved Routing Topology (CPCRT) for congestion control in mobile ad hoc networks. CPCRT aims to distinguish between packet loss due to link failure versus other causes like congestion. It takes a cross-layer approach using information from the physical, MAC, and application layers. The proposed method also aims to conserve power during packet transmission by adjusting transmission power levels based on received signal strength. Simulation results show that CPCRT can better utilize resources and conserve power during congestion control compared to other approaches.
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.
Resource Dependent Radio Allocation For Battlefield Communications - A Data M...IJERA Editor
Network Enabled Capability (NEC) and the Land Open Systems Architecture (LOSA) are novel approaches to enable interoperability between a heterogeneous collection of assets in the battlefield. These paradigms utilise an underlying network for cooperation between deployed battlefield equipment. NEC and LOSA have great potential to transform military communications and enhance integrated survivability as well as situational awareness, but the Achilles’ heel of NEC and LOSA is the wireless spectrum over which they must communicate. A noisy and dynamic battlefield wireless spectrum as well as an array of heterogeneous wireless communications equipment handling multiple types of data with different Quality of Service (QoS) requirements requires a system which manages and allocates these communication resources effectively. This paper presents the High Availability Wireless Communications (HAWC) system, a hardware agnostic communications controller middleware to manage any combination of existing and future multiband wireless resources. The system utilises a vehicle’s data model to gather information about available radio resources and enable LOSA by meeting communications data requirements and delivering appropriate QoS to the appropriate traffic in a fleet of vehicles. The functionality of the system is verified by using behavioural simulation on a virtual battlefield.
GLOBAL FRONTRUNNER ROUTING ALGORITHM (GFRA) FOR V2V COMMUNICATION IN VANETS cscpconf
VANET (Vehicular Ad hoc NETwork) is the emerging research area that making the phrase
“Network on Wheel” true. In this new age network the basic WLAN (IEEE 802.11) standard is
used. As the necessity of such network increases the implementation challenges are being taken
into account. They are broadcasting, routing, priority scheduling and security and privacy. In
this paper the routing is considered as the research factor. A proposal for routing with
frequently changing topology to avoid disconnection of network on road and for the routing
among overlapping networks in flyovers with multiple ramps and stack to avoid wrong
messaging is given.
GLOBAL FRONTRUNNER ROUTING ALGORITHM (GFRA) FOR V2V COMMUNICATION IN VANETS cscpconf
This document proposes a Global Frontrunner Routing Algorithm (GFRA) to address routing challenges in Vehicular Ad Hoc Networks (VANETs). GFRA aims to minimize transmission delays by reducing the number of hops needed to route emergency messages between vehicles. It determines the distance and direction to the destination vehicle, and if it is over 1000m away, forwards the message to the nearest "frontrunner" vehicle along the direction of travel. This frontrunner or subsequent frontrunners will continue forwarding the message until it reaches the destination vehicle. Simulation results will evaluate GFRA's performance in reducing delays compared to multi-hop routing protocols for VANETs. The algorithm
Similar to contention resolution diversity slotted.pdf (20)
MASSIVE MACHINE TYPE COMMUNICATION TOWARDS 6G.pdfYAAKOVSOLOMON1
This white paper explores key research directions for machine type communication (MTC) towards 6G networks by 2030. It discusses the main societal drivers of MTC, such as autonomous mobility and smart manufacturing. Representative MTC use cases are presented across various industries. Emerging MTC services are expected to have highly diverse requirements in terms of performance metrics like reliability, latency, energy efficiency, and scalability. The white paper investigates potential enabling technologies for building a holistic MTC network architecture in 6G that can efficiently support both massive and critical MTC services.
This document provides an overview and table of contents for the book "IoT and Low-Power Wireless: Circuits, Architectures, and Techniques". The book is edited by Christopher Siu and Krzysztof Iniewski and contains 12 chapters covering various topics related to Internet of Things (IoT) and low-power wireless technologies. The table of contents lists the chapter titles and authors for each chapter in the book. The document also provides information about the book series that this book is part of.
RANDOM MAC OPTIMIZATION FOR IOT COMMUNICATION.pdfYAAKOVSOLOMON1
This document summarizes a research paper on optimizing random MAC protocols for IoT communication. It begins by introducing the growth of IoT and issues with collisions that can occur without central coordination. It then discusses how IRSA and CRDSA protocols attempt to reduce collisions by using random repetition of packets. The document reviews the history of IoT and key technologies like TCP/IP that enabled its development. Finally, it outlines important characteristics of IoT like scalability, critical applications, and the need for low-cost communication protocols to support the large number of connected devices expected in the future.
Multi-slot Coded ALOHA with Irregular Degree.pdfYAAKOVSOLOMON1
This document proposes an improvement to the Multi-slot Coded ALOHA (MuSCA) random multiple access scheme for satellite communications. The improvement involves applying variable code rates and irregular user degree distributions, where the code rate and degree for each user are selected according to a probability distribution. This allows the system to achieve higher throughput compared to the original MuSCA scheme and other related schemes like Contention Resolution Diversity Slotted ALOHA (CRDSA). The document describes how the system would work, including encoding data into codewords that are split into multiple bursts and transmitted on random slots, and decoding the received signal using successive interference cancellation. It analyzes the potential throughput gain from optimizing the irregular degree distribution.
Machine-Type-Communication in 5G Cellular System-Li_Yue_PhD_2018.pdfYAAKOVSOLOMON1
This document is a dissertation submitted by Yue Li for the degree of Doctor of Philosophy at the University of Victoria. The dissertation focuses on improving transmission efficiency for machine-type communication (MTC) devices in 5G cellular systems. Specifically, it proposes applying network coding and device-to-device communications to MTC devices to improve efficiency. It also proposes using floating relays deployed via unmanned aerial vehicles to proactively improve channel quality for MTC devices experiencing high shadowing. The dissertation provides theoretical analyses and performance evaluations of the proposed approaches.
Massive_MTC_An_Overview and Perspectives Towards 5G.pdfYAAKOVSOLOMON1
The document provides an overview of 5G mobile networks and their ability to support massive machine-type communications (mMTC). Some key points:
- 5G networks are expected to be operational by 2020 and will enable up to 50 billion connected devices through technologies like M2M, D2D, and V2V communications.
- 5G aims to consolidate all existing machine-type communications onto a single platform based on the Internet of Things (IoT) concept to create an Internet of Everything enabling smart cities and a fully networked society.
- 5G is expected to significantly increase data speeds, reduce latency, improve energy efficiency, and support a vast number of low-power devices and new applications.
Graph-based Random-Access Protocols for Massive Multiple Access Networks.pdfYAAKOVSOLOMON1
The document is a dissertation submitted by Shun Ogata for the degree of Doctor of Philosophy. It proposes novel random access schemes for massive multiple access networks using frameless ALOHA. Specifically, it proposes ZigZag decodable frameless ALOHA, which introduces ZigZag decoding to resolve collisions in frameless ALOHA. It also proposes frameless ALOHA with multiple base station cooperation, where base stations share retrieved packets over a backhaul network. Finally, it combines ZigZag decoding and multiple base station cooperation in a single scheme. Analysis and simulations show the proposed schemes achieve higher throughput than conventional schemes.
Massive MTC An Overview and Perspectives Towards 5G (2).pdfYAAKOVSOLOMON1
This document provides an overview of massive machine-type communications (MMC) and perspectives towards 5G networks. It discusses how 5G will enable the integration of all known machine-to-machine communication technologies through a single infrastructure, creating an environment for smart cities and a fully networked society under the new Internet of Everything concept. By 2020, it is predicted that 5G networks will support up to 50 billion connected devices and provide higher data speeds, lower latency, and improved quality of service compared to 4G networks. This will allow for new applications in areas like automation, transportation, healthcare, and more.
This document is the thesis submitted by Oscar del Río Herrero for the degree of Doctor of Philosophy at Universitat Ramon Llull in Barcelona, Spain in 2015. The thesis proposes three novel random access schemes for satellite communications: Contention Resolution Diversity Slotted Aloha (CRDSA), Asynchronous Contention Resolution Diversity Aloha (ACRDA), and Enhanced Spread Spectrum Aloha (E-SSA). CRDSA uses strong error correction codes and successive interference cancellation to achieve high throughput for slotted systems. ACRDA extends this technique to unslotted systems using spreading sequences. E-SSA applies similar concepts to spread spectrum systems. The performance of the schemes is
Extended LTE Coverage for Indoor Machine Type Communication.pdfYAAKOVSOLOMON1
This document discusses extending LTE coverage for indoor machine type communication. It proposes using repetition to increase coverage without requiring hardware upgrades. Simulations show that with a 20 dB coverage increase through repetition, coverage can be almost complete for inter-site distances up to 2500 m, where standard LTE has gaps. Higher resource usage is required but the number of supported users is limited more by coverage at longer distances than resources. Uplink performance is also evaluated through link and system level simulations.
Key Enabling Technologies of 5G Wireless Mobile Communication.pdfYAAKOVSOLOMON1
The document discusses key enabling technologies of 5G wireless mobile communication. It provides an overview of 5G technology, including its features such as high speed, low latency and high capacity. It describes 5G's equipment providers and the countries that have conducted early experiments with 5G including India, South Korea and San Marino. The document outlines 5G's architecture and discusses several key enabling technologies that are used in 5G networks, such as device-to-device communication, machine-to-machine communication, and millimeter wave technology.
The document discusses coded slotted ALOHA (CSA) and other coded random access schemes for massive machine-type communications. It begins with background on the increasing problem of multiple access for large populations of users. It then reviews classical random access schemes like slotted ALOHA and more modern coded schemes like CRDSA, IRSA, and CSA. CSA uses error correcting codes, where users transmit encoded segments of data over randomly selected slots, allowing throughput higher than traditional schemes to be achieved without feedback. The performance of CSA and related protocols is analyzed using a bipartite graph representation and density evolution techniques from coding theory.
Finite-Length Performance Analysis of Slotted ALOHA-Thesis.pdfYAAKOVSOLOMON1
Finite-Length Performance Analysis of Slotted ALOHA with Interference Cancellation analyzes the performance of Irregular Repetition Slotted ALOHA (IRSA) for finite frame lengths. It develops a matrix-based analysis to derive a semi-analytical expression for packet loss rate. Through computer simulations, it shows the proposed analysis allows exact computation of packet loss rate for small user numbers and frame lengths, unlike previous asymptotic analyses for infinite users and frames.
6G Internet of Things - A Comprehensive Survey.pdfYAAKOVSOLOMON1
The document provides a comprehensive survey of the convergence of 6G technologies and Internet of Things (IoT). It discusses how 6G is expected to empower future IoT networks through technologies like edge intelligence, reconfigurable intelligent surfaces, terahertz communications, and blockchain. It then explores the opportunities brought by 6G for various emerging IoT applications in domains like healthcare, vehicular networking, satellites, and industry. The survey identifies key research challenges in areas such as security, energy efficiency, and standardization and points to potential directions for future 6G-IoT research.
Frameless ALOHA is a random access protocol inspired by rateless codes that uses successive interference cancellation (SIC) to resolve packet collisions. It operates without a predefined frame length, adding slots until a stopping criterion is met like resolving a certain fraction of users. The analysis shows the protocol can achieve high throughput asymptotically by optimizing the slot access probability. The capture effect from stronger signals can further boost performance by enabling intra-slot SIC. Noise impacts the achievable throughput, requiring higher optimized slot degrees to counter its effects.
This document presents a thesis that analyzes random access protocols for satellite networks considering multipacket reception over block fading channels. It begins with a review of random access protocols like slotted ALOHA. It then discusses collision and block fading channel models and threshold-based decoding in the absence and presence of coding. It develops probability matrices for multipacket reception when the number of packets is 2 or 3. It also analyzes irregular repetition slotted ALOHA (IRSA) through graphical representations and generating distributions. It evaluates the theoretical bounds and provides simulations comparing different distributions. Finally, it presents various numerical results analyzing the performance of slotted ALOHA, coded slotted ALOHA and IRSA under different channel conditions.
Presentation of IEEE Slovenia CIS (Computational Intelligence Society) Chapte...University of Maribor
Slides from talk presenting:
Aleš Zamuda: Presentation of IEEE Slovenia CIS (Computational Intelligence Society) Chapter and Networking.
Presentation at IcETRAN 2024 session:
"Inter-Society Networking Panel GRSS/MTT-S/CIS
Panel Session: Promoting Connection and Cooperation"
IEEE Slovenia GRSS
IEEE Serbia and Montenegro MTT-S
IEEE Slovenia CIS
11TH INTERNATIONAL CONFERENCE ON ELECTRICAL, ELECTRONIC AND COMPUTING ENGINEERING
3-6 June 2024, Niš, Serbia
Embedded machine learning-based road conditions and driving behavior monitoringIJECEIAES
Car accident rates have increased in recent years, resulting in losses in human lives, properties, and other financial costs. An embedded machine learning-based system is developed to address this critical issue. The system can monitor road conditions, detect driving patterns, and identify aggressive driving behaviors. The system is based on neural networks trained on a comprehensive dataset of driving events, driving styles, and road conditions. The system effectively detects potential risks and helps mitigate the frequency and impact of accidents. The primary goal is to ensure the safety of drivers and vehicles. Collecting data involved gathering information on three key road events: normal street and normal drive, speed bumps, circular yellow speed bumps, and three aggressive driving actions: sudden start, sudden stop, and sudden entry. The gathered data is processed and analyzed using a machine learning system designed for limited power and memory devices. The developed system resulted in 91.9% accuracy, 93.6% precision, and 92% recall. The achieved inference time on an Arduino Nano 33 BLE Sense with a 32-bit CPU running at 64 MHz is 34 ms and requires 2.6 kB peak RAM and 139.9 kB program flash memory, making it suitable for resource-constrained embedded systems.
DEEP LEARNING FOR SMART GRID INTRUSION DETECTION: A HYBRID CNN-LSTM-BASED MODELgerogepatton
As digital technology becomes more deeply embedded in power systems, protecting the communication
networks of Smart Grids (SG) has emerged as a critical concern. Distributed Network Protocol 3 (DNP3)
represents a multi-tiered application layer protocol extensively utilized in Supervisory Control and Data
Acquisition (SCADA)-based smart grids to facilitate real-time data gathering and control functionalities.
Robust Intrusion Detection Systems (IDS) are necessary for early threat detection and mitigation because
of the interconnection of these networks, which makes them vulnerable to a variety of cyberattacks. To
solve this issue, this paper develops a hybrid Deep Learning (DL) model specifically designed for intrusion
detection in smart grids. The proposed approach is a combination of the Convolutional Neural Network
(CNN) and the Long-Short-Term Memory algorithms (LSTM). We employed a recent intrusion detection
dataset (DNP3), which focuses on unauthorized commands and Denial of Service (DoS) cyberattacks, to
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6th International Conference on Machine Learning & Applications (CMLA 2024)ClaraZara1
6th International Conference on Machine Learning & Applications (CMLA 2024) will provide an excellent international forum for sharing knowledge and results in theory, methodology and applications of on Machine Learning & Applications.
1. Coherent Contention Resolution
Diversity Slotted ALOHA: An Improved
Multiple Access Method for Satellite
IoT System
Ziwei Liu1
*, Tiantian Zhu1
, Chen Zhang1
, Gengxin Zhang1
and Shanshan Zhao2
1
College of Telecommunications and Information Engineering, Telecommunication and Networks National Engineering Research
Center, Nanjing University of Posts and Telecommunications, Nanjing, China, 2
College of Electronic and Optical Engineering,
Nanjing University of Posts and Telecommunications, Nanjing, China
For Beyond 5G/6G system, satellite communication systems become an effective
component of the space and terrestrial integrated network. Among typical
applications, massive Machine Type of Communication (mMTC) is a promising and
challenging application. The demands of low power consumption and light signaling
make random access methods as the potential solution. Up to now, contention
resolution-based ALOHA methods, such as contention resolution diversity slotted
ALOHA (CRDSA), improve the throughput significantly. However, its throughput will
meet the inflection point soon with the normalized load increasing since collisionless
packets are hardly existing. In fact, the diversity of transmitting packets is not utilized
totally. In this paper, an improved random access method, named coherent CRDSA
method (C-CRDSA), is proposed. It accumulates replicated packets coherently at
receiver and further improve the throughput over CRDSA. Detailed derivations and
simulations are given. Simulation results corroborate the effectiveness of the proposed
method.
Keywords: coherent accumulation, CRDSA, multiple access, internet of things, satellite communication
INTRODUCTION
Space and terrestrial integrated network can provide seamless and tridimensional information
services for the whole planet (Liu et al., 2018). It will promote the development of the communication
system and has become the core component of B5G/6G communication system (Chen et al., 2020).
Among varies of applications, Internet of Things (IoT) is a significant scenario to serve massive
machine-type communication. Terrestrial IoT terminals communicate through cellular networks
with narrow-band IoT (NB-IoT) or LoRa protocol, which is relatively complete (Leonardi et al.,
2019). However, for some special geographic areas, such as deserts, forests and oceans, the terrestrial
cellular network cannot support the IoT application for the lack of coverage. Besides, some crowds
gathering area will need extra access support. To cover these problems, satellite IoT system become a
good candidate.
Satellite communication systems are distributed in space and are not restricted by geographic
location. A properly designed satellite constellation can provide not only all-day, global seamless
coverage, but also higher reliability and resistance connection (Fraire et al., 2020). However, due to
the wide coverage, the simultaneous access number of terminal nodes in the satellite IoT system will
Edited by:
Wei Feng,
Tsinghua University, China
Reviewed by:
Kefeng Guo,
Space Engineering University, China
Lexi Xu,
China United Network
Communications Group, China
*Correspondence:
Ziwei Liu
lzw@njupt.edu.cn
Specialty section:
This article was submitted to
Aerial and Space Networks,
a section of the journal
Frontiers in Space Technologies
Received: 09 August 2021
Accepted: 20 September 2021
Published: 20 October 2021
Citation:
Liu Z, Zhu T, Zhang C, Zhang G and
Zhao S (2021) Coherent Contention
Resolution Diversity Slotted ALOHA:
An Improved Multiple Access Method
for Satellite IoT System.
Front. Space Technol. 2:755546.
doi: 10.3389/frspt.2021.755546
Frontiers in Space Technologies | www.frontiersin.org October 2021 | Volume 2 | Article 755546
1
ORIGINAL RESEARCH
published: 20 October 2021
doi: 10.3389/frspt.2021.755546
2. reach ten thousand to million. It becomes a great challenge on
system throughput and access efficiency.
Traditional fixed-allocation multiple access methods are
widely used, and the channel utilization rate is relatively high
(Liu et al., 2006). Unfortunately, it fits the fixed connection
demand or costs precious control signaling. For the satellite
IoT system, most terminals transmit burst packets. Moreover,
the long propagation delay and low power consumption demand
make it impossible to request resources dynamically (Qu et al.,
2019). Therefore, in this scenario, any multiple access scheme
based on fixed or dynamic resource allocation is not applicable.
On the contrary, we turn to random access technology. The
terminal can compete for communication resources without
scheduling, which is more suitable for the satellite IoT system.
In the past few decades, ALOHA-based random access
technology has been continuously improved to support the
satellite IoT multiple access demand. Slotted ALOHA (SA) is
first discussed after pure ALOHA (Gurcan et al., 1997). A frame is
divided into time slots of the same length. Each terminal can only
send data packets in a specified time slot. If multiple terminals
select the same time slot to send their data packets, collision will
occur and all of the colliding packets will be failure to access. Its
maximum normalized throughput can only reach 0.36
theoretically, which is far from the system requirement.
Diversity slotted ALOHA (DSA) improves performance by
transmitting multiple replicas of the terminal on the basis of
slotted ALOHA. When the normalized load is low, the
throughput of DSA is improved over SA since replicas can
help access in collisionless slots. For heavy load scenario, the
throughput degrades rapidly for more collision occurring from
too many replicas. In order to solve the problem of packet
collision, the contention resolution diversity slotted ALOHA
(CRDSA) was proposed, in which packet diversity
transmission and iterative interference cancellation were
effectively combined. It promotes the maximum normalized
throughput to about 0.55 (Casini et al., 2007).
Moreover, some improved methods were proposed, such as
CRDSA++, IRSA and so on (Meloni and Murroni, 2012; Lee et al.,
2012; Mengali et al., 2017; Kissling, 2011, Zhao et al., 2019, Liva,
2011). Compared with CRDSA, CRDSA++ allows terminals to
transmit more than 2 identical duplicate packets. More replicas
can provide a little more improvement on throughput. IRSA
made further improvements by optimizing the number of replicas
of data packets sent by each terminal. Except for CRDSA, an
asynchronous scheme called Asynchronous Contention
Resolution Diversity Slot Access Technology (ACRDA) and its
improved versions were proposed in the literature (De Gaudenzi
et al., 2014; Wong et al., 2017; Almonacid and Franck, 2017).
However, asynchronous access methods suffer lower throughput
when they keep the benefit of low complexity. Although the
above-mentioned random access technologies have greatly
improved performances compared with original ALOHA, they
all will suffer the “avalanche effect”. As the normalized load
increases, their access effect will drop sharply. It is still necessary
to modify throughput performance in heavy load scenario. In
order to overcome this shortage, the power difference between
data packets is used to solve the collision problem (Alvi et al.,
2018; Zheng et al., 2014). However, due to the particularity of the
satellite-ground distance and the inapplicability of small IoT
terminals for power control, the power difference between
data packets is not easy to obtain in satellite IoT systems.
In fact, packet diversity and iteratively cancellation is still an
available solution. The key is to build the cancellation condition
properly at receiver. In this paper, inspired by CRDSA++ and
ACRDA, an improved diversity slotted random access scheme is
proposed. Each terminal transmits a virtual slotted subframe in
which all the replicas are coherent and have the same interval
with each other. At receiver, the traditional iteratively
cancellation in CRDSA with collisionless replica and the
introduced coherent accumulation operation is alternatively
executed. When there is lack of collisionless replica, the sliding
coherent accumulation operation is applied to potential virtual
subframes to construct the signal-to-noise gain. Packets from the
same terminal can be accumulated and enough gain will lead to
successful cancellation and break a new breach for next round
iteratively cancellation. With the proposed scheme, the
throughput will be improved apparently, especially in the
heavy load scenario. Simulation results verify the effectiveness
of the proposed method.
The rest of this paper is organized as follows. System and
Signal Model gives the system and signal model this paper
concerned. The proposed scheme is illustrated in Using
Coherent Accumulation to Cancel Collided Data Packet. In the
Throughput Analysis With Detailed Derivations, detailed
derivations of the throughput are given. All the performance
are evaluated in the Performance Simulation and conclusion is
presented in the Conclusion.
SYSTEM AND SIGNAL MODEL
Satellite IoT Access Scenario
In this paper, the satellite IoT is considered for remote areas like
deserts and ocean areas. It is composed of satellite nodes, ground
gateways and a large number of IoT terminals. Among them, the
IoT terminal is used for the sensing and collecting information.
Satellites are used to accept and forwarding the information or
signals. The ground gateway station is used for authentication
management and processing centers. A brief diagram is shown in
Figure 1. When the satellite receives the data frame information
transmitted by the terminal, it forwards it to the ground customs
station for data analysis and processing.
In most cases, IoT terminals can be divided into two types,
namely periodically transmitting type and event-driven type.
Periodically transmitting type of terminals keep in dormancy
until the pre-set period reach. Then they will transmit the
collected data and turn into dormancy again. The event-driven
type of terminals will keep in dormancy until triggered by
operator or outer event. This type of terminals is usually more
functional than periods types. However, both of these two types of
terminals need long standby time and low power consumption.
As a result, they will save as much power as possible during its
transmitting period. No complicated signaling on access resource
allocation or power control is admitted. However, ephemeris is
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Liu et al. Multiple Access of Satellite IoT
3. stored in each terminal and their own locations can be obtained
by Global Navigation Satellite System (GNSS) systems.
Signal Transmitting Model
Instead of traditional time division multiple access (TDMA), we
turn to slotted ALOHA-based breach. Inspired by CRDSA++, in
the proposed method, each terminal transmits E packets
coherently. Here the coherence means the packets in a virtual
subframe contain the same information and modulated by the
coherent carrier. The expression of the first data packet
transmitted by terminal c is shown in Eq. 1.
Sc(t) Pc · cos2πfct + θc(t) + φc t ∈ [tc, tc + tm] (1)
tm is the length of each time slot. Pc represents the power
transmitted by the terminal c. fc represents the signal central
frequency, φc is the initial phase of the signal and θc(t) contains
the modulation information. tc is the initial time slot selected by
terminal c. Here it is assumed that Doppler shift of all packets are
pre-compensated during transmitting using ephemeris and the
terminal location.
The E data packets transmitted by each terminal can be
regarded as an independent virtual subframe. The first data
packet transmitted by the terminal is randomly selected in the
frame with the step of one slot. The following E − 1 data packets
are transmitted with a fixed time interval. The fixed time slot
interval is different from each terminal, and it is selected within
the interval range [1, N] by every terminal. Data packets from the
same terminal contain the location information of every replica.
The virtual frame can be expressed by Eq. 2. The entire data
subframe is shown in Figure 2. In the figure, it shows that
terminal 1 transmits the first data packet in time slot 2 and
selects interval between data packets is one time slots. These three
data packets transmitted by terminal 1 can be regarded as a virtual
subframe.
Yvf(c) {Sc(t), Sc(t + n · tm), · · ·, Sc(t + n · (E − 1) · tm)} (2)
Received Signal Model
Due to short time interval between each data packet in a subframe
and short-term stability of Doppler, the channel state between
each packet can be viewed as stationary. The Doppler frequency
shift between data packets which come from the same terminal is
approximately equal in the subframe. When the access subframe
reaches the receiver, all the packets will keep the coherence
FIGURE 1 | Satellite IoT system working diagram.
FIGURE 2 | Signal transmitting mechanism.
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Liu et al. Multiple Access of Satellite IoT
4. between each other. Eq. 3 expresses the signal model with
multiple signals collision in wth time slot. The initial time of
wth time slot is tw. v(t) is Gaussian white noise.
Ycollision(w)
z
i1
hi
pi
cos2πfit + θi(t) + φi + v(t)
t ∈ [tw, tw + tm]
(3)
It must be pointed out that there is no correlation between data
packet signals from different terminals and noise is independent
with all the signals.
USING COHERENT ACCUMULATION TO
CANCEL COLLIDED DATA PACKET
With the coherence in the received subframe, coherent
accumulation can be achieved to increase the signal-to-
interference-plus-noise ratio (SINR) and build the collision
separation condition, which is widely used in radar system
(You et al., 2006). The phase between different replicas will
maintain constant so as to be processed coherently.
Considering the potential Doppler shift, Fast Fourier
transformation (FFT) is usually performed to accumulate
coherent signals (Yuan et al., 2016).
Yaccq
E
n1
Sc(t + ntm)ej2π
kq
N0 (4)
In our design, the Doppler shift is compensated before
transmitting. The accumulation is simplified into the zero-
channel output of the FFT filter bank, i.e., a summator.
Yaccq
E
n1
Sc(t + ntm) (5)
In the receiver, when the traditional iteratively interference
cancellation procedure is stuck, the coherent accumulation is
activated to break the “cross lock” situation in the CRDSA
receiving scheme. In order to search for all the potential
accumulation subframe, a group of sliding windows with all
possible subframe width should be applied to scan the whole
access frame. The receiver sets the length of the sliding window
to (E − 1) · N + 1 time slots. Within the sliding window, E time
slots are locked. Only all the packets from one terminal fall into
one window can be accumulated. The more packets used, the
more SINR gain it collected. The coherent packets will be
accumulated with amplitude raising to E times while
incoherent packets, such as packets from different
terminals, and noise raise E times power. The SINR gain
comes from
G 10 log10 E (6)
The sliding window moves one time a slot forward when the
data in the first window has been accumulated and canceled.
Move the window perform the above operations iteratively until
all the time slots have been accumulated at least once. The
diagram of the whole receiving scheme is shown in Figure 3.
With the separation, some locked collision packets will be
cancelled. Then iteratively interference cancellation procedure
can continue with more collisionless packets being unfolded. In
what follows, the detailed derivations about the throughput
improvement are given to illustrate the advantage of the
proposed method.
THROUGHPUT ANALYSIS WITH DETAILED
DERIVATIONS
The key to analyze the throughput is to uncover the improvement
that coherent accumulation imposes on the regular CRDSA. To
make the derivations more comprehensive, it is started with the
fixed length of the virtual subframe.
Take E 3 and 2 slot intervals as an example. Figures 4A,B
show that within the first sliding window, terminal 1 transmits
its packets in the first, fourth, and seventh time slot. The
accumulation will be applied to these three slots since it is
assumed all the virtual subframes are the same with E 3 and 2
slot intervals. In these three slots, only terminal 2 and 5
transmit one packet. As a result, the packets transmitted by
the terminal 1 can use the SINR difference created by coherent
accumulation to separate and cancel all three packets. Then the
sliding window moves forward by one time slot, which is
shown in Figure 4C. All the slots will be accumulated at
least once with window sliding.
Without loss of generality, it is assumed that the data packet
transmitted by the terminal satisfies the Poisson distribution with
the parameter λ in the time slot interval tm. The normalized load
FIGURE 3 | The diagram of the whole receiving scheme.
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Liu et al. Multiple Access of Satellite IoT
5. can be expressed as G λtm. The probability of k data packets
arriving in a time slot tm is:
P
(λtm)k
k!
e−λtm
(7)
The probability that no other data packets are transmitted in
this time slot is:
P
(λtm)k
k!
e−λtm
|k0 e−λtm
e−G
(8)
In the above case, it only needs to pay attention to the time slot
in which each terminal transmits the first data packet since
whether a data packet transmitted can be successfully
separated mainly depends on the fact that there are other
terminals choosing the same slots as the first slot to
FIGURE 4 | Use sliding window to accumulate signal power and separate collision data packets with N 3. (A) First sliding window. (B) Terminal 1 separated
successfully. (C) Sliding to next step.
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Liu et al. Multiple Access of Satellite IoT
6. transmitting packets or not. The probability that a data packet
transmitted by a terminal is successfully separated is:
Ps
M − 4N
M − 2N
· e−3λtm
+
2N
M − 2N
· e−2λtm
M − 4N
M − 2N
· e−3G
+
2N
M − 2N
· e−2G
(9)
Transmitting the first data packet in the last 2N time slots in
the data frame, which is unsuccessful by default. We replace with
G′ and G′ M
M−2N · G.
Ps
M − 4N
M − 2N
· e−3G’
+
2N
M − 2N
· e−2G’
(10)
Then we can obtain the extra throughput that coherent
accumulation can provide in this case is:
T1 G · Ps (11)
With the above-mentioned derivation basements, the
more general case that each terminal transmits packets
with random interval can be analyzed. All the intervals
are chosen within the interval range [1, N], where the
maximum transmission interval is N. This increases the
selectivity of the terminal to transmit data packets, and
can increase the number of terminals whose signals can
be separated. As shown in Figure 5, since each terminal
randomly selects the transmitting interval, the data packet of
FIGURE 5 | All terminals transmit data packets with different and random intervals.
FIGURE 6 | Coherent accumulation separation fails when the interval between the terminal transmitting data packets with two time slots.
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Liu et al. Multiple Access of Satellite IoT
7. terminal 1 can be successfully separated in the first sliding
window.
On the other hand, random selection scheme increases the
complexity of throughput derivations. A terminal whose interval
between transmitting packets is n will also be affected by
terminals with packet interval of n/2 and packet interval of 2n
and so on. As shown in Figure 6, it shows that all situations where
colliding data packets cannot be separated.
In the Figure 6, a*, b*, and c* are the cases where the
transmission interval of other terminals is n time slots. In
these cases, according to the idea in the previous section, only
the time slot where each terminal transmits the first data
packet is considered to determine whether the terminal with
interval n can be successfully separated. If the time slot where
the current terminal transmits the first data packet is s1, then
it is necessary to see if there are other terminals transmitting
the first data packet in time slots s1 − n, s1, and s1 + n.
Different from the previous section, even if a terminal
transmits the first data packet in the above-mentioned
time slot, it also depends on whether the number of data
packet intervals is n since the number of data packet intervals
transmitted by all terminals is randomly selected within N
time slots. For the data packets transmitted in the first n time
slots and the last n time slots in the data frame, there are only
two cases that cause the data packets to be unable to be
separated. Then the probability that the data packet can be
separated is:
Pn
M − 2N − 2n
M − 2N
· ⎛
⎝e
−
1
N
14. ·G’
(12)
FIGURE 7 | Use iterative interference cancellation technology to eliminate collision data packets on the received data frame (A) Virtual subframe with free replica.
(B) Iteratively interference cancellation finished with terminal 1 and 4 received.
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Liu et al. Multiple Access of Satellite IoT
15. The rest of the situation is summarized in what follows. Under
different scenarios, the probability that data packets can be
successfully separated when the data packet interval for the
terminal to transmit is n time slots.
• Case of n: probability of successful access
Pn M−2N−2n
M−2N · e
(− 3
N)·G’
+ 2n
M−2N · e
(− 2
N)·G’
• Case of n and n/
2: pn M−2N−2n
M−2N · e
(− 5
N)·G’
+ n
M−2N · e
(− 4
N)·G’
+ n
M−2N · exp
(− 3
N)·G’
• Case of n and
2n: pn M−2N−4n
M−2N · e
(− 5
N)·G’
+ 2n
M−2N · e
(− 4
N)·G’
+ 2n
M−2N · e
(− 3
N)·G’
• Else:pn M−2N−4n
M−2N · e
(− 7
N)·G’
+ 2n
M−2N · e
(− 6
N)·G’
+ 2n
M−2N · e
(− 5
N)·G’
Up to now, the throughput improvement of the coherent
accumulation has been analyzed. In what follows, we will give the
final throughput and packet loss ratio (PLR) of the whole
C-CRDSA method with the combination of coherent
accumulation cancellation and iterative interference
cancellation technology.
With coherent accumulation applied, more clean time slots
will be created. Iterative interference cancellation can continue to
be applied. The process is shown in Figure 7. On the data frame
where the signal is separated through coherent accumulation, the
iterative interference cancellation technology and the data
packets on the clean time slot are used to eliminate the
collided data packets.
It can be seen from Figure 7 that terminal 1 and terminal 5
unfold new clean time slots for terminal 2 after using iterative
interference cancellation. With coherent accumulation and
separation, the normalized load of the data packets that have
not been successfully separated is:
Gp
(Gp
G · (1 − PS)) (13)
When the number of iterations in the system is L
and the normalized load is Gp
, the throughput can be
expressed as:
T(L
Gp
) Gp
· Ppd(L
Gp
) (14)
In Eq. 14, Ppd(L|Gp
) represents the probability
that the data packet is successfully decoded when the load is Gp
and iterates L times. The probability can be expressed as:
Ppd(L
Gp
) 1−1−P1
pd(L
Gp
)·1−P2
pd(L
Gp
)·1
−P3
pd(L
Gp
) (15)
P1
pd(L
G*
), P2
pd(L
G*
), and P3
pd(L|G*
) represent the
probability that the three replicas of the data packet sent
by the same terminal will be successfully demodulated when
the load is Gp
and the number of iterations is L. However, it
should be noted that unlike the independent demodulation of
each data packet from the same terminal, the proposed
scheme makes it be independent with other packets. The
normalized throughput of C-CRDSA can be derived as:
FIGURE 8 | Simulation results of throughput of coherent accumulation, theoretical results of coherent accumulation and SA.
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Liu et al. Multiple Access of Satellite IoT
16. FIGURE 9 | Simulation results of PLR of coherent accumulation, theoretical results of coherent accumulation and SA.
FIGURE 10 | Simulation results of throughput of C-CRDSA at different, CRDSA and SA.
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Liu et al. Multiple Access of Satellite IoT
17. FIGURE 11 | Simulation results of PLR of C-CRDSA at different, CRDSA and SA.
FIGURE 12 | Throughput simulation with different diversity order.
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Liu et al. Multiple Access of Satellite IoT
18. T G · Ps + Gp
· Ppd(L
Gp
) (16)
Then the PLR in the system can be expressed as:
PLRMACG′ 1 −
TG′
G′
(17)
PERFORMANCE SIMULATION
In this section, detailed performance of the proposed method is
evaluated by simulations. First of all, the derivation results of the
coherent accumulation are verified. Then the performance of the
entire method is simulated. The simulation parameters are set as
follows. The total number of slots in each frame is 50. Normalized
load is set from 0 to 3 and the number of maximum slots interval
N is 5, 10 and 15, respectively. Every result is smoothed by Monte
Carlo methods with 1,000 times. The simulation results of
coherent accumulation are shown in Figures 8, 9.
From Figures 8, 9, the derivations of coherent accumulation to
eliminate collision data packets is consistent with the actual
simulation results. As the maximum data packet interval N
increases, the fewer cases the terminal sends data packets that
cannot be separated. As N increases, the performance of the
scheme gets better. The major merit of this scheme is that in
heavy load areas, the access performance of the system will not
suddenly deteriorate compared to conventional random access
technology. This is in accordance with the motivation of
our work.
In order to verify the improvement and effect of the
proposed scheme, we compare the proposed scheme with
the CRDSA and SA. Figures 10, 11 give out the comparison
results.
From the above two simulation diagrams, it can be seen that
in the heavy load area, the throughput of CRDSA will have a
deep drop. The reason is that it is difficult to have collisionless
replicas in the heavy load area. C-CRDSA overcome this
phenomenon by using coherent accumulation. Moreover, it
also provides good performance in the low load area.
C-CRDSA reaches the peak throughput at load G 1.5
packets/slot, but it still has good access effect in the
subsequent load range. Also, the SA is outperformed.
Besides, it can be seen from Figure 10 that when N is larger,
the overall throughput will be better for the reason that possible
subframe collisions decrease, reducing the situation that data
packets cannot be separated through coherent accumulation.
When N 15, the peak throughput is about 1.02 packets/slot
and the normalized load is 1.5 packets/slot. C-CRDSA also
improve the performance of the scheme using coherent
accumulation to separate collision packets alone in low load
areas, which can be found in Figures 8, 9. For the same
reason, PLR is also improved over CRDSA, SA and coherent
accumulation alone. However, it must be noted that it is
impossible to increase the interval as will. The longer the
interval is, the more channel state will alter. Nonstationary
channel response will make the replicas lose coherence,
leading to accumulation failure.
To discuss a more practical design, a simulation with
different diversity order is executed. Similar with IRSA, a
polynomial is used to describe the different diversity order
amount. The result is shown in Figure 12. From Figure 12,
it can be seen that different diversity order will affect a lot for
throughput. Different diversity order distribution will lead to
different throughput performance. This inspires us to make
further research to improve the proposed scheme. This will
become our next work.
CONCLUSION
Random access is a potential choice of multiple access scheme in
the satellite IoT system. However, the sharp degradation of the
throughput in the heavy load scenario makes existing methods
cannot support real application. In this paper, a modified
collision-tolerant slotted ALOHA method is proposed. With
the requirement of coherently transmitting, all diversity
packets from access terminals will be decoded by iteratively
interference cancellation and coherent accumulation
cancellation. Coherent accumulation can further break the
cross lock after iteratively interference cancellation. The
closed-form throughput expression of the proposed method is
derived. Simulation results show that the proposed method can
successfully improve the throughput and packet loss ratio in
heavy load scenario and maintain the superior performance in
light load scenario.
DATA AVAILABILITY STATEMENT
The raw data supporting the conclusions of this article will be
made available by the authors, without undue reservation.
AUTHOR CONTRIBUTIONS
ZL and TZ led the main contribution and writing of the
manuscript. ZL conceived the original idea and provided
supervision. CZ and GZ contributed to the developed
techniques. SZ supervised the findings of this work. All authors
contributed to the manuscript and approved the submitted version.
FUNDING
This work has been supported by National Science Foundation of
China (No. 91738201) and Jiangsu Province Basic Research
Project (No. BK20192002).
Frontiers in Space Technologies | www.frontiersin.org October 2021 | Volume 2 | Article 755546
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Liu et al. Multiple Access of Satellite IoT