The Experts below are selected from a list of 10434 Experts worldwide ranked by ideXlab platform
Lie-liang Yang - One of the best experts on this subject based on the ideXlab platform.
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Throughput of Network Coding Nodes Employing Go-Back-N or Selective-repeat automatic repeat request
Network Coding at Different Layers in Wireless Networks, 2016Co-Authors: Yang Qin, Lie-liang YangAbstract:The steady-state performance of general network coding nodes is investigated, when data are transmitted in packets based on the go-back-N automatic repeat request (GBN-ARQ) or selective-repeat ARQ (SR-ARQ) error-control scheme. A general network coding node is assumed to have H incoming links that provide packets for forming the coded packets transmitted by one outgoing link. Each of the incoming and outgoing links is assumed to have some buffers for temporarily storing the data packets. The state transitions of network coding nodes employing GBN-ARQ or SR-ARQ are analyzed, which shows that the operations of a general network coding node can be modeled by a finite state machine. Therefore, the expressions for the steady-state throughput of general network coding nodes are derived based on the properties of finite-state machines. Furthermore, the throughput performance of network coding nodes is investigated by both simulations and evaluation of the expressions obtained. The studies show that the simulation results converge closely to the numerical results, which justify the effectiveness of the analytical expressions derived. Furthermore, the studies show that the packet error rate, the capacity of buffer, and the number of incoming links may impose significant impact on the performance of general network coding nodes.
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Throughput and Delay Analysis of Cognitive Go-Back-N Hybrid automatic repeat request Using Discrete-Time Markov Modelling
IEEE Access, 2016Co-Authors: Ateeq Ur Rehman, Chen Dong, Varghese A. Thomas, Lie-liang Yang, Lajos HanzoAbstract:Dataset supporting: Ateeq Ur Rehman et al "Throughput and Delay Analysis of Cognitive Go-Back-N Hybrid automatic repeat request Using Discrete-Time Markov Modelling".
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Performance of Cognitive Selective-repeat Hybrid automatic repeat request
IEEE Access, 2016Co-Authors: Ateeq Ur Rehman, Varghese A. Thomas, Lie-liang Yang, Lajos HanzoAbstract:Dataset supporting: Ateeq Ur Rehman et al, "Performance of Cognitive Selective-repeat Hybrid automatic repeat request".In this paper, a novel transmission protocol is proposed based on the classical Selective-repeat Hybrid automatic repeat to access a primary user (PU) channel, which is referred to as the CSR-HARQ. We assume that the PU transmits information based on time-slots (TSs). During a TS, the cognitive radio (CR) transmitter first senses the PU channel. Once a free TS is found, it transmits a number of packets to the CU receiver based on the principles of the SR-HARQ. In this paper, we analyze the throughput, average packet delay and end-to-end packets delay of the CSR-HARQ. We proposed a pair of analytical approaches. The first one is probability based, while the second one relies on the classic discrete time markov chain (DTMC) principles. Finally, we study the throughput, average packet delay as well as the end-to-end packet delay of the CSR-HARQ both by simulations and by evaluating our formulas. The simulation-based studies agree well with the analytical results. The performance of the CSR-HARQ systems is significantly impacted by the activity of the PU channel and by the reliability of the spectrum sensing.
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VTC Spring - Performance of Cognitive Hybrid automatic repeat request: Go-Back-N
2016 IEEE 83rd Vehicular Technology Conference (VTC Spring), 2016Co-Authors: Ateeq Ur Rehman, Lie-liang Yang, Lajos HanzoAbstract:In this paper, we propose a cognitive Go-Back-N Hybrid automatic repeat request (CGBN-HARQ) scheme for a cognitive radio (CR) system to opportunistically transmit data over a primary radio (PR) channel. We model the activity of PR users (PRUs) occupying the PR channel as a Markov chain with two states: `ON' and `OFF'. In order to use the PR channel, the CR system first senses the availability/unavailability of the PR channel. Once it finds that the PR channel is free, the CR system transmits data packets over the PR channel's spectrum, whilst relying on the principles of GBN-HARQ. In this paper, we investigate both the throughput and delay of CGBN-HARQ, with a special emphasis on the impact of various system parameters involved in the scenarios of both perfect and imperfect spectrum sensing. Our studies demonstrate that the activity of PRUs, the transmission reliability of the CR system as well as the number of packets transmitted per time-slot may have a substantial impact on both the throughput and the delay of the CR system.
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VTC Spring - Performance of Cognitive Hybrid automatic repeat request: Stop-and-Wait
2015 IEEE 81st Vehicular Technology Conference (VTC Spring), 2015Co-Authors: Ateeq Ur Rehman, Lie-liang Yang, Lajos HanzoAbstract:Detecting spectrum holes and efficiently accessing them are the two basic functions that enable a cognitive radio (CR) to make use of the licensed spectrums of a primary radio (PR). In this paper, we consider a CR scheme, which opportunistically accesses a PR channel for communication between a pair of nodes based on the stop-and-wait hybrid automatic repeat request (SW-HARQ). Hence, it is referred to as the cognitive SW-HARQ (CSW-HARQ) arrangement. In our CSW-HARQ system, the PR channel is modelled as a two-state Markov chain having `On' and `Off' states. The CR may only access the PR channel in its `Off' state. In this paper, we analyze both the throughput and delay performance of the CSW-HARQ system, for which a range of closed-form formulas are derived that are also validated by simulation results. Our performance results show that both the activities of PR users and the reliability of the CR channel have a substantial impact on the achievable performance of the CR system.
Lajos Hanzo - One of the best experts on this subject based on the ideXlab platform.
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Throughput and Delay Analysis of Cognitive Go-Back-N Hybrid automatic repeat request Using Discrete-Time Markov Modelling
IEEE Access, 2016Co-Authors: Ateeq Ur Rehman, Chen Dong, Varghese A. Thomas, Lie-liang Yang, Lajos HanzoAbstract:Dataset supporting: Ateeq Ur Rehman et al "Throughput and Delay Analysis of Cognitive Go-Back-N Hybrid automatic repeat request Using Discrete-Time Markov Modelling".
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Performance of Cognitive Selective-repeat Hybrid automatic repeat request
IEEE Access, 2016Co-Authors: Ateeq Ur Rehman, Varghese A. Thomas, Lie-liang Yang, Lajos HanzoAbstract:Dataset supporting: Ateeq Ur Rehman et al, "Performance of Cognitive Selective-repeat Hybrid automatic repeat request".In this paper, a novel transmission protocol is proposed based on the classical Selective-repeat Hybrid automatic repeat to access a primary user (PU) channel, which is referred to as the CSR-HARQ. We assume that the PU transmits information based on time-slots (TSs). During a TS, the cognitive radio (CR) transmitter first senses the PU channel. Once a free TS is found, it transmits a number of packets to the CU receiver based on the principles of the SR-HARQ. In this paper, we analyze the throughput, average packet delay and end-to-end packets delay of the CSR-HARQ. We proposed a pair of analytical approaches. The first one is probability based, while the second one relies on the classic discrete time markov chain (DTMC) principles. Finally, we study the throughput, average packet delay as well as the end-to-end packet delay of the CSR-HARQ both by simulations and by evaluating our formulas. The simulation-based studies agree well with the analytical results. The performance of the CSR-HARQ systems is significantly impacted by the activity of the PU channel and by the reliability of the spectrum sensing.
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VTC Spring - Performance of Cognitive Hybrid automatic repeat request: Go-Back-N
2016 IEEE 83rd Vehicular Technology Conference (VTC Spring), 2016Co-Authors: Ateeq Ur Rehman, Lie-liang Yang, Lajos HanzoAbstract:In this paper, we propose a cognitive Go-Back-N Hybrid automatic repeat request (CGBN-HARQ) scheme for a cognitive radio (CR) system to opportunistically transmit data over a primary radio (PR) channel. We model the activity of PR users (PRUs) occupying the PR channel as a Markov chain with two states: `ON' and `OFF'. In order to use the PR channel, the CR system first senses the availability/unavailability of the PR channel. Once it finds that the PR channel is free, the CR system transmits data packets over the PR channel's spectrum, whilst relying on the principles of GBN-HARQ. In this paper, we investigate both the throughput and delay of CGBN-HARQ, with a special emphasis on the impact of various system parameters involved in the scenarios of both perfect and imperfect spectrum sensing. Our studies demonstrate that the activity of PRUs, the transmission reliability of the CR system as well as the number of packets transmitted per time-slot may have a substantial impact on both the throughput and the delay of the CR system.
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VTC Spring - Performance of Cognitive Hybrid automatic repeat request: Stop-and-Wait
2015 IEEE 81st Vehicular Technology Conference (VTC Spring), 2015Co-Authors: Ateeq Ur Rehman, Lie-liang Yang, Lajos HanzoAbstract:Detecting spectrum holes and efficiently accessing them are the two basic functions that enable a cognitive radio (CR) to make use of the licensed spectrums of a primary radio (PR). In this paper, we consider a CR scheme, which opportunistically accesses a PR channel for communication between a pair of nodes based on the stop-and-wait hybrid automatic repeat request (SW-HARQ). Hence, it is referred to as the cognitive SW-HARQ (CSW-HARQ) arrangement. In our CSW-HARQ system, the PR channel is modelled as a two-state Markov chain having `On' and `Off' states. The CR may only access the PR channel in its `Off' state. In this paper, we analyze both the throughput and delay performance of the CSW-HARQ system, for which a range of closed-form formulas are derived that are also validated by simulation results. Our performance results show that both the activities of PR users and the reliability of the CR channel have a substantial impact on the achievable performance of the CR system.
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Hybrid automatic-repeat-request Systems for Cooperative Wireless Communications
IEEE Communications Surveys & Tutorials, 2014Co-Authors: Hoang Anh Ngo, Lajos HanzoAbstract:Hybrid-automatic-repeat-request H-ARQ has become an indispensable technique in reliable communication systems. Hence, in this paper we review the state-of-art and investigate the performance of H-ARQ in the context of cooperative wireless communications. As a novel advance, we also propose a relay-switching regime based H-ARQ scheme, which is capable of increasing the achievable system throughput as confirmed by both theory and practice. Furthermore, we evaluate the achievable upper-bound performance in the context of perfect Channel State Information CSI. Then we proceed to quantify the performance erosion imposed by realistic CSI-based-coherent detection as well as low complexity non-coherent detection assisted cooperative H-ARQ. Finally, we propose a general design guide-lines for H-ARQ aided cooperative systems.
Thomas Eriksson - One of the best experts on this subject based on the ideXlab platform.
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Coordinated Hybrid automatic repeat request; Extended Version
arXiv: Information Theory, 2014Co-Authors: Behrooz Makki, Tommy Svensson, Thomas Eriksson, Mohamed-slim AlouiniAbstract:We develop a coordinated hybrid automatic repeat request (HARQ) approach. With the proposed scheme, if a user message is correctly decoded in the first HARQ rounds, its spectrum is allocated to other users, to improve the network outage probability and the users' fairness. The results, which are obtained for single- and multiple-antenna setups, demonstrate the efficiency of the proposed approach in different conditions. For instance, with a maximum of M retransmissions and single transmit/receive antennas, the diversity gain of a user increases from M to (J+1)(M-1)+1 where J is the number of users helping that user.
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Coordinated Hybrid automatic repeat request
IEEE Communications Letters, 2014Co-Authors: Behrooz Makki, Tommy Svensson, Thomas Eriksson, Mohamed-slim AlouiniAbstract:We develop a coordinated hybrid automatic repeat request (HARQ) approach. With the proposed scheme, if a user message is correctly decoded in the first HARQ rounds, its spectrum is allocated to other users, to improve the network outage probability and the users' fairness. The results, which are obtained for single- and multiple-antenna setups, demonstrate the efficiency of the proposed approach in different conditions. For instance, with a maximum of $M$ retransmissions and single transmit/receive antennas, the diversity gain of a user increases from $M$ to $(J+1)(M-1)+1$ where $J$ is the number of users helping that user.
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power allocation in repetition time diversity hybrid automatic repeat request feedback
Wireless Communications and Networking Conference, 2012Co-Authors: Behrooz Makki, Alexandre Graell I Amat, Thomas ErikssonAbstract:This paper addresses the problem of optimal power allocation for hybrid automatic repeat request (HARQ) feedback over slowly-fading channels. We mainly focus on the repetition time diversity HARQ scheme where the results are obtained for both continuous and bursting communication models. Moreover, the effect of an outage probability constraint on the system data transmission efficiency is studied under different transmission power constraints. Simulation results show that 1) for Nakagami fading channels, the optimal HARQ-based (re)transmission powers maximizing the system throughput should be decreasing in every (re)transmission round, 2) higher rates are achieved in the continuous communication, when compared with the bursting model, and 3) HARQ feedback leads to considerable performance improvement even in outage-limited conditions.
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WCNC - Power allocation in repetition time diversity hybrid automatic repeat request feedback
2012 IEEE Wireless Communications and Networking Conference (WCNC), 2012Co-Authors: Behrooz Makki, Alexandre Graell I Amat, Thomas ErikssonAbstract:This paper addresses the problem of optimal power allocation for hybrid automatic repeat request (HARQ) feedback over slowly-fading channels. We mainly focus on the repetition time diversity HARQ scheme where the results are obtained for both continuous and bursting communication models. Moreover, the effect of an outage probability constraint on the system data transmission efficiency is studied under different transmission power constraints. Simulation results show that 1) for Nakagami fading channels, the optimal HARQ-based (re)transmission powers maximizing the system throughput should be decreasing in every (re)transmission round, 2) higher rates are achieved in the continuous communication, when compared with the bursting model, and 3) HARQ feedback leads to considerable performance improvement even in outage-limited conditions.
Behrooz Makki - One of the best experts on this subject based on the ideXlab platform.
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Coordinated Hybrid automatic repeat request; Extended Version
arXiv: Information Theory, 2014Co-Authors: Behrooz Makki, Tommy Svensson, Thomas Eriksson, Mohamed-slim AlouiniAbstract:We develop a coordinated hybrid automatic repeat request (HARQ) approach. With the proposed scheme, if a user message is correctly decoded in the first HARQ rounds, its spectrum is allocated to other users, to improve the network outage probability and the users' fairness. The results, which are obtained for single- and multiple-antenna setups, demonstrate the efficiency of the proposed approach in different conditions. For instance, with a maximum of M retransmissions and single transmit/receive antennas, the diversity gain of a user increases from M to (J+1)(M-1)+1 where J is the number of users helping that user.
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Coordinated Hybrid automatic repeat request
IEEE Communications Letters, 2014Co-Authors: Behrooz Makki, Tommy Svensson, Thomas Eriksson, Mohamed-slim AlouiniAbstract:We develop a coordinated hybrid automatic repeat request (HARQ) approach. With the proposed scheme, if a user message is correctly decoded in the first HARQ rounds, its spectrum is allocated to other users, to improve the network outage probability and the users' fairness. The results, which are obtained for single- and multiple-antenna setups, demonstrate the efficiency of the proposed approach in different conditions. For instance, with a maximum of $M$ retransmissions and single transmit/receive antennas, the diversity gain of a user increases from $M$ to $(J+1)(M-1)+1$ where $J$ is the number of users helping that user.
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power allocation in repetition time diversity hybrid automatic repeat request feedback
Wireless Communications and Networking Conference, 2012Co-Authors: Behrooz Makki, Alexandre Graell I Amat, Thomas ErikssonAbstract:This paper addresses the problem of optimal power allocation for hybrid automatic repeat request (HARQ) feedback over slowly-fading channels. We mainly focus on the repetition time diversity HARQ scheme where the results are obtained for both continuous and bursting communication models. Moreover, the effect of an outage probability constraint on the system data transmission efficiency is studied under different transmission power constraints. Simulation results show that 1) for Nakagami fading channels, the optimal HARQ-based (re)transmission powers maximizing the system throughput should be decreasing in every (re)transmission round, 2) higher rates are achieved in the continuous communication, when compared with the bursting model, and 3) HARQ feedback leads to considerable performance improvement even in outage-limited conditions.
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WCNC - Power allocation in repetition time diversity hybrid automatic repeat request feedback
2012 IEEE Wireless Communications and Networking Conference (WCNC), 2012Co-Authors: Behrooz Makki, Alexandre Graell I Amat, Thomas ErikssonAbstract:This paper addresses the problem of optimal power allocation for hybrid automatic repeat request (HARQ) feedback over slowly-fading channels. We mainly focus on the repetition time diversity HARQ scheme where the results are obtained for both continuous and bursting communication models. Moreover, the effect of an outage probability constraint on the system data transmission efficiency is studied under different transmission power constraints. Simulation results show that 1) for Nakagami fading channels, the optimal HARQ-based (re)transmission powers maximizing the system throughput should be decreasing in every (re)transmission round, 2) higher rates are achieved in the continuous communication, when compared with the bursting model, and 3) HARQ feedback leads to considerable performance improvement even in outage-limited conditions.
Yang Qin - One of the best experts on this subject based on the ideXlab platform.
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Throughput of Network Coding Nodes Employing Go-Back-N or Selective-repeat automatic repeat request
Network Coding at Different Layers in Wireless Networks, 2016Co-Authors: Yang Qin, Lie-liang YangAbstract:The steady-state performance of general network coding nodes is investigated, when data are transmitted in packets based on the go-back-N automatic repeat request (GBN-ARQ) or selective-repeat ARQ (SR-ARQ) error-control scheme. A general network coding node is assumed to have H incoming links that provide packets for forming the coded packets transmitted by one outgoing link. Each of the incoming and outgoing links is assumed to have some buffers for temporarily storing the data packets. The state transitions of network coding nodes employing GBN-ARQ or SR-ARQ are analyzed, which shows that the operations of a general network coding node can be modeled by a finite state machine. Therefore, the expressions for the steady-state throughput of general network coding nodes are derived based on the properties of finite-state machines. Furthermore, the throughput performance of network coding nodes is investigated by both simulations and evaluation of the expressions obtained. The studies show that the simulation results converge closely to the numerical results, which justify the effectiveness of the analytical expressions derived. Furthermore, the studies show that the packet error rate, the capacity of buffer, and the number of incoming links may impose significant impact on the performance of general network coding nodes.
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Performance of general network coding nodes with stop-and-wait automatic repeat request transmission
IET Communications, 2012Co-Authors: Yang Qin, Lie-liang YangAbstract:The steady-state performance of general network coding node is investigated, when data are transmitted in packets based on the stop-and-wait automatic repeat request error-control scheme. The general network coding node considered has H number of incoming links that provide packets for forming the coded packets transmitted by one outgoing link. Each of the incoming and outgoing links is assumed to have some buffers for temporarily storing the data packets. The state transition of the general network coding node is modelled by a finite state machine, and its steady-state performance is derived based on the properties of discrete-time Markov chain. Specifically, the throughput, blocking probability and the distribution of contents are analysed, when the general network coding node is operated in the steady state. The performance of the general network coding node is investigated either by simulations or by evaluation of the formulas derived in this study. The performance results show that the analytical formulas obtained can be well justified by the simulation results. Furthermore, it can be shown that the packet error rate, the capacity of buffer and the number of incoming links may impose significant impact on the performance of general network coding node.
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Steady-state throughput analysis of network coding nodes employing stop-and-wait automatic repeat request
IEEE ACM Transactions on Networking, 2012Co-Authors: Yang Qin, Lie-liang YangAbstract:This paper analyzes the steady-state throughput of network coding nodes when data is transmitted based on the stop-and-wait automatic repeat request (SW-ARQ) scheme. The state transition of network coding nodes employing SW-ARQ is analyzed, which shows that the operations of network coding nodes can be modeled by a finite state machine. Therefore, the throughput expressions of network coding nodes can be derived based on the properties of finite state machines. Furthermore, the throughput performance of network coding nodes is investigated either by simulations or by evaluation of the expressions obtained. It can be shown that the simulation results converge closely to the numerical results and justify the effectiveness of our analytical expressions obtained.
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ISWCS - Throughput comparison of automatic repeat request assisted Butterfly networks
2010 7th International Symposium on Wireless Communication Systems, 2010Co-Authors: Yang Qin, Lie-liang YangAbstract:The maximum achievable throughput and the steady-state throughput of the Butterfly networks are investigated and compared in the context of three types of automatic repeat request (ARQ) schemes of, namely, the stop-and-wait ARQ (SW-ARQ), go-back-iV ARQ (GBN-ARQ) and the selective-repeat ARQ (SR-ARQ). Our studies show that, at a given packet error rate (PER), the SW-ARQ scheme yields the lowest throughput while the SR-ARQ scheme can attain the highest throughput, among the three ARQ schemes considered. At a very low PER, the GBN-ARQ may achieve a similar throughput as the SR-ARQ. However, as the PER increases, the throughput achieved by the GBN-ARQ converges to that of the SW-ARQ.
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ISWCS - Delay comparison of automatic repeat request assisted Butterfly networks
2010 7th International Symposium on Wireless Communication Systems, 2010Co-Authors: Yang Qin, Lie-liang YangAbstract:The average burst delay and the standard deviation (SD) of burst delay in the context of the Butterfly networks are investigated and compared, when three types of automatic repeat request (ARQ) schemes, namely, the stop-and-wait ARQ (SW-ARQ), go-back-N ARQ (GBN-ARQ) and the selective-repeat ARQ (SR-ARQ), are considered. We assume that packets in a burst arrive at a constant rate and that the packet error rate (PER) is the same for all the links. Our studies show that, among the three ARQ schemes, the SW-ARQ scheme yields the highest average burst delay and also the highest SD of burst delay, while the SR-ARQ scheme is capable of attaining the lowest delay and also the lowest SD of burst delay. At very low PER, the GBN-ARQ may achieve a similar delay performance as the SR-ARQ. However, as the PER increases, the delay performance of the GBN-ARQ converges to that of the SW-ARQ.
