A Gaussian channel with additive interference that is causally known to the transmitter is called a Dirty-Tape Channel(DTC).In this paper,we consider a state-dependent dirty-tape Gaussian relay channel with orthogonal...A Gaussian channel with additive interference that is causally known to the transmitter is called a Dirty-Tape Channel(DTC).In this paper,we consider a state-dependent dirty-tape Gaussian relay channel with orthogonal channels from the source to the relay and from the source and relay to the destination.The orthogonal channels are corrupted by two independent additive interferences causally known to both the source and relay.The lower and upper bounds of the channel capacity are established.The lower bound is obtained by employing superposition coding at the source,Partial Decode-and-Forward(PDF)relaying at the relay,and a strategy similar to that used by Shannon at the source and relay.The explicit capacity is characterised when the power of the relay is sufficiently large.Finally,several numerical examples are provided to illustrate the impact of additive interferences and the role of the relay in information transmission and in removing the interference.展开更多
With the rapid development of the smart grid, it is necessary to do good corresponding work in relaying protection so as to meet the overall requirements of the smart grid better. So we must focus on the state divisio...With the rapid development of the smart grid, it is necessary to do good corresponding work in relaying protection so as to meet the overall requirements of the smart grid better. So we must focus on the state division, risk analysis and fault diagnosis methods in the relaying protection system, in the basis of fully understanding the advantages and disadvantages of relaying protection system, and then improve the problems existing of relaying protection system at this stage according to the actual situation. This paper aims at the overview of analysis on state evaluation of relaying protection systems.展开更多
In cognitive radio (CR) relay networks,most previous work concentrates on maximizing physical layer quality of service (QoS),e.g.,spectral efficiency and achievable data rate,as relay selection criteria.However,the re...In cognitive radio (CR) relay networks,most previous work concentrates on maximizing physical layer quality of service (QoS),e.g.,spectral efficiency and achievable data rate,as relay selection criteria.However,the residual energy state of relay nodes is largely ignored,which has significant effects on the average network lifetime for those battery-limited wireless networks.In this paper,an opportunistic distributed best-relay node selection scheme is proposed for cooperative transmissions over underlay-paradigm based CR networks,and meanwhile guarantee that the primary link is provided with a minimum-rate for a certain percentage of time.The objective is to increase achievable data rate as well as prolong average network lifetime.Specifically,both the instantaneous channel state information (ICSI) and residual energy of candidate relay nodes are taken as weighted metric,and the relay node with the optimal weighted metric is selected as the best one.Simulation results are presented to demonstrate the effectiveness of the proposed scheme.展开更多
A cross-layer design which combines adaptive modulation and coding (AMC) at the physical layer with a hybrid automatic repeat request (HARQ) protocol at the data link layer (LL) is presented, in cooperative relay syst...A cross-layer design which combines adaptive modulation and coding (AMC) at the physical layer with a hybrid automatic repeat request (HARQ) protocol at the data link layer (LL) is presented, in cooperative relay system over Nakagami-m fading channels with perfect and imperfect channel state information (CSI). In order to maximize spectral efficiency (SE) under delay and packet error rate (PER) performance constraints, a state transition model and an optimization framework with perfect CSI are presented. Then the framework is extended to cooperative relay system with imperfect CSI. The numerical results show that the scheme can achieve maximum SE while satisfying transmitting delay requirements. Compared with the imperfect CSI, the average PER with perfect CSI is much lower and the spectral efficiency is much higher.展开更多
在不完全信道状态信息和非理想连续干扰消除条件下对存在窃听者的非正交多址系统安全性能问题进行研究,提出一个存在窃听者的解码转发中继辅助非正交多址接入系统(Decode and Forward Cooperative Relay in Non-Orthogonal Multiple Acc...在不完全信道状态信息和非理想连续干扰消除条件下对存在窃听者的非正交多址系统安全性能问题进行研究,提出一个存在窃听者的解码转发中继辅助非正交多址接入系统(Decode and Forward Cooperative Relay in Non-Orthogonal Multiple Access System with Eavesdropper,DFCR-E-NOMA)。在该系统中,分析了在不完全的信道状态信息和非理想连续干扰消除同时存在的条件下系统的安全性能,利用中断概率和截获概率表征系统的安全性能,通过蒙特卡罗模拟仿真分析了功率分配系数、信道估计误差对所提系统性能的影响。验证结果表明,在信道条件一定的情况下,可通过设置较高的数据传输速率,在基站或中继处选择合适的功率分配系数能够有效降低窃听者的截获概率。展开更多
针对基于无线携能通信(SWIPT, simultaneous wireless information and power transfer)和非正交多址接入(NOMA, non-orthogonal multiple access)的认知中继(CR, cognitive relay)(SWIPT-NOMA-CR)网络,考虑非理想顺序干扰消除(SIC, suc...针对基于无线携能通信(SWIPT, simultaneous wireless information and power transfer)和非正交多址接入(NOMA, non-orthogonal multiple access)的认知中继(CR, cognitive relay)(SWIPT-NOMA-CR)网络,考虑非理想顺序干扰消除(SIC, successive interference cancellation)和信道状态信息(CSI, channel state information)实际情况,研究系统在采用理想、时间开关(TS, time switching)和功率分割(PS, power splitting)3种中继传输方案时次用户的中断性能。推导出次用户中断概率的解析表达式,并通过蒙特卡洛仿真验证理论推导的正确性。实验结果表明,非理想SIC和CSI会导致次用户的中断性能下降,相对于非理想CSI,非理想SIC给系统中断性能带来的损失更大。此外,用户采用PS中继传输方案的中断概率比采用TS方案低,当改变非理想SIC和CSI因子时,采用PS方案用户的中断概率差值比TS方案小,说明PS中继传输方案的可靠性优于TS方案。展开更多
优化链路状态路由协议(Optimized Link State Routing,OLSR)是Ad Hoc网络中的一种先验式的链路状态路由协议,在该协议基础上,通过在HELLO消息中加入二跳邻节点信息进行一跳广播,节点能获取所有的二跳邻节点及三跳邻节点,从二跳邻节点中...优化链路状态路由协议(Optimized Link State Routing,OLSR)是Ad Hoc网络中的一种先验式的链路状态路由协议,在该协议基础上,通过在HELLO消息中加入二跳邻节点信息进行一跳广播,节点能获取所有的二跳邻节点及三跳邻节点,从二跳邻节点中选出中继节点(称之为多点二级中继节点MPL2R)覆盖三级邻节点,再从一跳邻节点中选出中继节点(称之为一级中继节点MPL1R,即原来的MPR),MPL2R和MPL1R完成了对所有的二跳和三跳邻节点的覆盖。修改TC消息内容,并改进MPR节点选择算法。通过对OLSR路由协议的改进,增加了路由开销,但从全局看,最后计算出的路径更接近全局最优。展开更多
路由协议是无线移动自组网(Mobile Ad Hoc Networks,MANETs)的关键技术之一。针对优化链路状态路由(Optimized Link SState Routing,OLSR)协议中的多点中继(Multipoint Relay,MPR)覆盖度对网络开销的影响进行了分析。OLSR协议与一般的...路由协议是无线移动自组网(Mobile Ad Hoc Networks,MANETs)的关键技术之一。针对优化链路状态路由(Optimized Link SState Routing,OLSR)协议中的多点中继(Multipoint Relay,MPR)覆盖度对网络开销的影响进行了分析。OLSR协议与一般的链路状态协议相比,其采纳了MPR机制,一定程度上抑制了网络中广播控制信息的洪泛,从而降低了网络中的控制开销,但是这种机制是否影响到路由的鲁棒性是值得探讨的问题。基于此,设计了相应的MPR选择算法并进行仿真实验。结果表明,适当提高MPR覆盖度能加快路由的收敛。展开更多
基金supported by the Fundamental Research Funds for the Central Universities under Grants No.2013B08214,No2009B32114the National Natural Science Foundation of China under Grants No.61271232,No.60972045,No.61071089+1 种基金the Open Research Fund of National Mobile Communications Research Laboratory,Southeast University under Grant No.2012D05the University Postgraduate Research and Innovation Project in Jiangsu Province under Grant No.CXZZ11_0395
文摘A Gaussian channel with additive interference that is causally known to the transmitter is called a Dirty-Tape Channel(DTC).In this paper,we consider a state-dependent dirty-tape Gaussian relay channel with orthogonal channels from the source to the relay and from the source and relay to the destination.The orthogonal channels are corrupted by two independent additive interferences causally known to both the source and relay.The lower and upper bounds of the channel capacity are established.The lower bound is obtained by employing superposition coding at the source,Partial Decode-and-Forward(PDF)relaying at the relay,and a strategy similar to that used by Shannon at the source and relay.The explicit capacity is characterised when the power of the relay is sufficiently large.Finally,several numerical examples are provided to illustrate the impact of additive interferences and the role of the relay in information transmission and in removing the interference.
文摘With the rapid development of the smart grid, it is necessary to do good corresponding work in relaying protection so as to meet the overall requirements of the smart grid better. So we must focus on the state division, risk analysis and fault diagnosis methods in the relaying protection system, in the basis of fully understanding the advantages and disadvantages of relaying protection system, and then improve the problems existing of relaying protection system at this stage according to the actual situation. This paper aims at the overview of analysis on state evaluation of relaying protection systems.
基金Sponsored by the National Major Science&Technology Project(Grand No.2009ZX03002-014)the National Nature Science Foundation(Grant No.60832009)+1 种基金the Beijing Municipal Natural Science Foundation(Grand No.4102044)the National Natural Science Foundation for Distinguished Young Scholar(Grand No.61001115)
文摘In cognitive radio (CR) relay networks,most previous work concentrates on maximizing physical layer quality of service (QoS),e.g.,spectral efficiency and achievable data rate,as relay selection criteria.However,the residual energy state of relay nodes is largely ignored,which has significant effects on the average network lifetime for those battery-limited wireless networks.In this paper,an opportunistic distributed best-relay node selection scheme is proposed for cooperative transmissions over underlay-paradigm based CR networks,and meanwhile guarantee that the primary link is provided with a minimum-rate for a certain percentage of time.The objective is to increase achievable data rate as well as prolong average network lifetime.Specifically,both the instantaneous channel state information (ICSI) and residual energy of candidate relay nodes are taken as weighted metric,and the relay node with the optimal weighted metric is selected as the best one.Simulation results are presented to demonstrate the effectiveness of the proposed scheme.
基金Sponsored by the National Science and Technology Major Special Project of China (Grant No.2011ZX03003-003-02)the Natural Science Foundation of China (Grant No. 60972070)+2 种基金the Natural Science Foundation of Chongqing (Grant No. CSTC2009BA2090)the Foundation of Chongqing Educational Committee ( Grant No. KJ100514)the Special Fund of Chongqing Key Laboratory
文摘A cross-layer design which combines adaptive modulation and coding (AMC) at the physical layer with a hybrid automatic repeat request (HARQ) protocol at the data link layer (LL) is presented, in cooperative relay system over Nakagami-m fading channels with perfect and imperfect channel state information (CSI). In order to maximize spectral efficiency (SE) under delay and packet error rate (PER) performance constraints, a state transition model and an optimization framework with perfect CSI are presented. Then the framework is extended to cooperative relay system with imperfect CSI. The numerical results show that the scheme can achieve maximum SE while satisfying transmitting delay requirements. Compared with the imperfect CSI, the average PER with perfect CSI is much lower and the spectral efficiency is much higher.
文摘在不完全信道状态信息和非理想连续干扰消除条件下对存在窃听者的非正交多址系统安全性能问题进行研究,提出一个存在窃听者的解码转发中继辅助非正交多址接入系统(Decode and Forward Cooperative Relay in Non-Orthogonal Multiple Access System with Eavesdropper,DFCR-E-NOMA)。在该系统中,分析了在不完全的信道状态信息和非理想连续干扰消除同时存在的条件下系统的安全性能,利用中断概率和截获概率表征系统的安全性能,通过蒙特卡罗模拟仿真分析了功率分配系数、信道估计误差对所提系统性能的影响。验证结果表明,在信道条件一定的情况下,可通过设置较高的数据传输速率,在基站或中继处选择合适的功率分配系数能够有效降低窃听者的截获概率。
文摘针对基于无线携能通信(SWIPT, simultaneous wireless information and power transfer)和非正交多址接入(NOMA, non-orthogonal multiple access)的认知中继(CR, cognitive relay)(SWIPT-NOMA-CR)网络,考虑非理想顺序干扰消除(SIC, successive interference cancellation)和信道状态信息(CSI, channel state information)实际情况,研究系统在采用理想、时间开关(TS, time switching)和功率分割(PS, power splitting)3种中继传输方案时次用户的中断性能。推导出次用户中断概率的解析表达式,并通过蒙特卡洛仿真验证理论推导的正确性。实验结果表明,非理想SIC和CSI会导致次用户的中断性能下降,相对于非理想CSI,非理想SIC给系统中断性能带来的损失更大。此外,用户采用PS中继传输方案的中断概率比采用TS方案低,当改变非理想SIC和CSI因子时,采用PS方案用户的中断概率差值比TS方案小,说明PS中继传输方案的可靠性优于TS方案。
文摘优化链路状态路由协议(Optimized Link State Routing,OLSR)是Ad Hoc网络中的一种先验式的链路状态路由协议,在该协议基础上,通过在HELLO消息中加入二跳邻节点信息进行一跳广播,节点能获取所有的二跳邻节点及三跳邻节点,从二跳邻节点中选出中继节点(称之为多点二级中继节点MPL2R)覆盖三级邻节点,再从一跳邻节点中选出中继节点(称之为一级中继节点MPL1R,即原来的MPR),MPL2R和MPL1R完成了对所有的二跳和三跳邻节点的覆盖。修改TC消息内容,并改进MPR节点选择算法。通过对OLSR路由协议的改进,增加了路由开销,但从全局看,最后计算出的路径更接近全局最优。
文摘路由协议是无线移动自组网(Mobile Ad Hoc Networks,MANETs)的关键技术之一。针对优化链路状态路由(Optimized Link SState Routing,OLSR)协议中的多点中继(Multipoint Relay,MPR)覆盖度对网络开销的影响进行了分析。OLSR协议与一般的链路状态协议相比,其采纳了MPR机制,一定程度上抑制了网络中广播控制信息的洪泛,从而降低了网络中的控制开销,但是这种机制是否影响到路由的鲁棒性是值得探讨的问题。基于此,设计了相应的MPR选择算法并进行仿真实验。结果表明,适当提高MPR覆盖度能加快路由的收敛。
