In large-scale networks such as the Internet of Things(IoT),devices seek multihop communication for longdistance communications,which considerably impacts their power exhaustion.Hence,this study proposes an energy har...In large-scale networks such as the Internet of Things(IoT),devices seek multihop communication for longdistance communications,which considerably impacts their power exhaustion.Hence,this study proposes an energy harvesting-enabled,relay-based communication in multihop clustered IoT networks in a bid to conserve the battery power in multihop IoT networks.Initially,this study proposes an efficient,hierarchical clustering mechanism in which entire IoT devices are clustered into two types:the closest cluster(CC)and remote clusters(RCs).Additionally,Euclidean distance is employed for the CC and fuzzy c-means for the RCs.Next,for cluster head(CH)selection,this study models a fitness function based on two metrics,namely residual energy and distance(device-to-device distance and device-to-sink distance).After CH selection,the entire clustered network is partitioned into several layers,after which a relay selection mechanism is applied.For every CH of the upper layer,we assign a few lower-layer CHs to function as relays.The relay selection mechanism is applied only for the devices in the RCs,while for devices in the CC,the CH functions as a relay.Finally,several simulation experiments are conducted to validate the proposed method’s performance.The results show the method’s superiority in terms of energy efficiency and optimal number of relays in comparison with the state-of-the-art methods.展开更多
This paper presents a symmetric cooperation strategy for cooperative relay networks with multiple users. The multi-user symmetric cooperation model and the relay selection algorithm are proposed. Then, the time slot a...This paper presents a symmetric cooperation strategy for cooperative relay networks with multiple users. The multi-user symmetric cooperation model and the relay selection algorithm are proposed. Then, the time slot allocation problem is cast into a bargaining problem, and the optimal time slot allocation solution is obtained by Nash bargaining solution （NBS）. Moreover, we also consider the implementations of the cooperation strategy, i.e., the grouping and admission control algorithm. Simulation results show that users can obtain larger rates under the symmetric cooperation strategy than the non-cooperative case.展开更多
Device-to-device （D2D） communication is an emerging technology for improving cellular networks, which plays an important role in realizing Internet of Things （IoT）. The spectrum efficiency, energy efficiency and t...Device-to-device （D2D） communication is an emerging technology for improving cellular networks, which plays an important role in realizing Internet of Things （IoT）. The spectrum efficiency, energy efficiency and throughput of network can be enhanced by the cooperation among multiple D2D users in a self-organized method. In order to limit the interference of D2D users and load off the energy consumption of D2D users without decreasing communication quality, an interference- limited multi-user cooperation scheme is proposed for multiple D2D users to solve the energy problem and the interference problem in this paper. Multiple D2D users use non-orthogonal spectrums to form clusters by self-organized method. Multiple D2D users are divided into different cooperative units. There is no interference among different cooperative units so as to limit the interference of each D2D user in cooperative units. When the link capacity cannot meet the requirements of the user rate, it will produce an interrupt event. In order to evaluate the communication quality, the outrage probability of D2D link is derived by considering link delay threshold, data rate and interference. Besides the energy availability and signal-to-noise ratio （SNR） of each D2D user, the distance between D2D users is considered when selecting the relaying D2D users so as to enhance the signal-to-interference-plus-noise ratio （SINR） of D2D receiving users. Combining the derived outrage probability, the relationships among the average link delay threshold, the efficiency of energy and the efficiency of capacity are studied. The simulation results show that the interference-limited multiple D2D users cooperation scheme can not only help to offioad energy consumption and limit the interference of D2D users, but also enhance the efficiency of energy and the efficiency of capacity.展开更多
在全双工多中继协作无线携能通信网络中,传统的中继选择算法未考虑到未被选择中继的闲置利用问题,导致中继数量增加时网络的性能浪费愈加严重,如何开发未被选择中继的剩余潜能成为提升网络性能的关键。对此,设计了一种新的HTT(Harvest t...在全双工多中继协作无线携能通信网络中,传统的中继选择算法未考虑到未被选择中继的闲置利用问题,导致中继数量增加时网络的性能浪费愈加严重,如何开发未被选择中继的剩余潜能成为提升网络性能的关键。对此,设计了一种新的HTT(Harvest then Transmit)功率消耗方案,在中继配备电池的情形下,通过充分利用中继处的能量收集模块增加了被选择中继处的发射功率,从而进一步提升了系统容量。此外,针对提出的新的HTT功率消耗方案,考虑了BIKT(Battery Information Known at Transmitter)和BIUT(Battery Information Unknown at Transmitter)两种应用场景。仿真实验的结果表明,3种中继选择算法,即单中继选择算法、贪婪中继选择算法和穷竭搜索算法,在采用提出的新的HTT功率消耗方案后,无论是应用于BIKT场景还是BIUT场景均能有效提升系统容量并降低中断概率。展开更多
In vehicular Ad-hoc network（VANET）, many multi-hop broadcast schemes are employed to widely propagate the warning messages among vehicles and the key is to dynamically determine the optimal relay vehicle for retrans...In vehicular Ad-hoc network（VANET）, many multi-hop broadcast schemes are employed to widely propagate the warning messages among vehicles and the key is to dynamically determine the optimal relay vehicle for retransmission. In order to achieve reliable and fast delivery of warning messages, this paper proposes a delay-aware and reliable broadcast protocol（DR-BP） based on transmit power control technique. First, a comprehensive model is derived to evaluate the transmission in vehicle-to-vehicle communications. This model considers the wireless channel fading, transmission delay and retransmissions characters occurring in the physical layer/medium access control（PHY/MAC） layer. Then, a local optimal relay selection mechanism based on the above model is designed. In DR-BP scheme, only the vehicle selected as the optimal relays can forward warning messages and the transmit power is time-varying. Finally, extensive simulations verify the performance of DR-BP under different traffic scenarios. Simulation results show that DR-BP outperforms the traditional slotted 1-persistence（S1P） and flooding scheme in terms of packets delivery ratio and transmission delay.展开更多
In this paper, we investigate the power-minimizing resource allocation problem in multiuser cooperative relay communication systems. A joint optimization problem involving subcarrier assignment, relay selection and po...In this paper, we investigate the power-minimizing resource allocation problem in multiuser cooperative relay communication systems. A joint optimization problem involving subcarrier assignment, relay selection and power allocation is formulated. Since the problem cannot be solved directly, we decompose it into three subproblems. According to the equivalent channel gains and the target rates of users, the subcarrier assignment and relay selection are conducted. Motivated by the water-filling algorithm, we propose a power allocation algorithm with cooperative features. Simulations results indicate that the proposed algorithm performs better in terms of the total transmit power consumption than the existing algorithms.展开更多
In this paper, the problem of communication security in an underlay wiretap cognitive radio network is addressed and statistically investigated. We rely on a simple dual-hop communication model of decode and forward r...In this paper, the problem of communication security in an underlay wiretap cognitive radio network is addressed and statistically investigated. We rely on a simple dual-hop communication model of decode and forward relay assisted network. Regarding the interference from primary users, interference power and maximum transmit power constraints; this network is subjected to multiple eavesdropping attacks which employ a specific interception strategy. To confound this eavesdropping, proposed selection schemes are exploited that aim at maximizing the minimum of the dual secrecy rates in order to strengthen the physical layer security. Moreover, exact and asymptotic closed form expressions are derived for specific performance metrics over independent and identically distributed Rayleigh fading channels. At high signal to interference noise ratio(SINR), tangential system bounds are also derived and discussed. Monte Carlo simulation results emphasize our assumption. It is found out that at the full diversity of the system, any additional node that enters the cooperative eavesdropping system becomes significantly of no effect.展开更多
文摘In large-scale networks such as the Internet of Things(IoT),devices seek multihop communication for longdistance communications,which considerably impacts their power exhaustion.Hence,this study proposes an energy harvesting-enabled,relay-based communication in multihop clustered IoT networks in a bid to conserve the battery power in multihop IoT networks.Initially,this study proposes an efficient,hierarchical clustering mechanism in which entire IoT devices are clustered into two types:the closest cluster(CC)and remote clusters(RCs).Additionally,Euclidean distance is employed for the CC and fuzzy c-means for the RCs.Next,for cluster head(CH)selection,this study models a fitness function based on two metrics,namely residual energy and distance(device-to-device distance and device-to-sink distance).After CH selection,the entire clustered network is partitioned into several layers,after which a relay selection mechanism is applied.For every CH of the upper layer,we assign a few lower-layer CHs to function as relays.The relay selection mechanism is applied only for the devices in the RCs,while for devices in the CC,the CH functions as a relay.Finally,several simulation experiments are conducted to validate the proposed method’s performance.The results show the method’s superiority in terms of energy efficiency and optimal number of relays in comparison with the state-of-the-art methods.
基金supported by National Basic Research Program of China (973 Program) (No. 2010CB731800)Key Project of National Natural Science Foundation of China (No. 60934003)Scientific and Technological Supporting Project of Hebei Province(No. 072435155D)
文摘This paper presents a symmetric cooperation strategy for cooperative relay networks with multiple users. The multi-user symmetric cooperation model and the relay selection algorithm are proposed. Then, the time slot allocation problem is cast into a bargaining problem, and the optimal time slot allocation solution is obtained by Nash bargaining solution （NBS）. Moreover, we also consider the implementations of the cooperation strategy, i.e., the grouping and admission control algorithm. Simulation results show that users can obtain larger rates under the symmetric cooperation strategy than the non-cooperative case.
基金This work was supported by the National Natural Science Foundation of China under Grant Nos. 61371097 and 61401051, the Chongqing Natural Science Foundation of China under Grant No. cstc2014jcyjA40039, and the Science and Technology Research Project of Chongqing Municipal Education Committee of China under Grant No. KJ1400402.
文摘Device-to-device （D2D） communication is an emerging technology for improving cellular networks, which plays an important role in realizing Internet of Things （IoT）. The spectrum efficiency, energy efficiency and throughput of network can be enhanced by the cooperation among multiple D2D users in a self-organized method. In order to limit the interference of D2D users and load off the energy consumption of D2D users without decreasing communication quality, an interference- limited multi-user cooperation scheme is proposed for multiple D2D users to solve the energy problem and the interference problem in this paper. Multiple D2D users use non-orthogonal spectrums to form clusters by self-organized method. Multiple D2D users are divided into different cooperative units. There is no interference among different cooperative units so as to limit the interference of each D2D user in cooperative units. When the link capacity cannot meet the requirements of the user rate, it will produce an interrupt event. In order to evaluate the communication quality, the outrage probability of D2D link is derived by considering link delay threshold, data rate and interference. Besides the energy availability and signal-to-noise ratio （SNR） of each D2D user, the distance between D2D users is considered when selecting the relaying D2D users so as to enhance the signal-to-interference-plus-noise ratio （SINR） of D2D receiving users. Combining the derived outrage probability, the relationships among the average link delay threshold, the efficiency of energy and the efficiency of capacity are studied. The simulation results show that the interference-limited multiple D2D users cooperation scheme can not only help to offioad energy consumption and limit the interference of D2D users, but also enhance the efficiency of energy and the efficiency of capacity.
文摘在全双工多中继协作无线携能通信网络中,传统的中继选择算法未考虑到未被选择中继的闲置利用问题,导致中继数量增加时网络的性能浪费愈加严重,如何开发未被选择中继的剩余潜能成为提升网络性能的关键。对此,设计了一种新的HTT(Harvest then Transmit)功率消耗方案,在中继配备电池的情形下,通过充分利用中继处的能量收集模块增加了被选择中继处的发射功率,从而进一步提升了系统容量。此外,针对提出的新的HTT功率消耗方案,考虑了BIKT(Battery Information Known at Transmitter)和BIUT(Battery Information Unknown at Transmitter)两种应用场景。仿真实验的结果表明,3种中继选择算法,即单中继选择算法、贪婪中继选择算法和穷竭搜索算法,在采用提出的新的HTT功率消耗方案后,无论是应用于BIKT场景还是BIUT场景均能有效提升系统容量并降低中断概率。
基金supported by the National Basic Research Program of China(2011CB302905)the National Natural Science Foundation of China(61170058)+3 种基金National Science and Technology Major Project(2011ZX03005-004-04,2012ZX03005009)the Research Fund for the Doctoral Program of Higher Education of China(20103402110041,20123402110019)the Guangdong Province and CAS Comprehensive Strategic Cooperation Projects(2012B090400013)the Fundamental Research Project of Suzhou(SYG201143)
文摘In vehicular Ad-hoc network（VANET）, many multi-hop broadcast schemes are employed to widely propagate the warning messages among vehicles and the key is to dynamically determine the optimal relay vehicle for retransmission. In order to achieve reliable and fast delivery of warning messages, this paper proposes a delay-aware and reliable broadcast protocol（DR-BP） based on transmit power control technique. First, a comprehensive model is derived to evaluate the transmission in vehicle-to-vehicle communications. This model considers the wireless channel fading, transmission delay and retransmissions characters occurring in the physical layer/medium access control（PHY/MAC） layer. Then, a local optimal relay selection mechanism based on the above model is designed. In DR-BP scheme, only the vehicle selected as the optimal relays can forward warning messages and the transmit power is time-varying. Finally, extensive simulations verify the performance of DR-BP under different traffic scenarios. Simulation results show that DR-BP outperforms the traditional slotted 1-persistence（S1P） and flooding scheme in terms of packets delivery ratio and transmission delay.
文摘In this paper, we investigate the power-minimizing resource allocation problem in multiuser cooperative relay communication systems. A joint optimization problem involving subcarrier assignment, relay selection and power allocation is formulated. Since the problem cannot be solved directly, we decompose it into three subproblems. According to the equivalent channel gains and the target rates of users, the subcarrier assignment and relay selection are conducted. Motivated by the water-filling algorithm, we propose a power allocation algorithm with cooperative features. Simulations results indicate that the proposed algorithm performs better in terms of the total transmit power consumption than the existing algorithms.
文摘In this paper, the problem of communication security in an underlay wiretap cognitive radio network is addressed and statistically investigated. We rely on a simple dual-hop communication model of decode and forward relay assisted network. Regarding the interference from primary users, interference power and maximum transmit power constraints; this network is subjected to multiple eavesdropping attacks which employ a specific interception strategy. To confound this eavesdropping, proposed selection schemes are exploited that aim at maximizing the minimum of the dual secrecy rates in order to strengthen the physical layer security. Moreover, exact and asymptotic closed form expressions are derived for specific performance metrics over independent and identically distributed Rayleigh fading channels. At high signal to interference noise ratio(SINR), tangential system bounds are also derived and discussed. Monte Carlo simulation results emphasize our assumption. It is found out that at the full diversity of the system, any additional node that enters the cooperative eavesdropping system becomes significantly of no effect.
