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It has been demonstrated that either Channel Allocation (CA) or Relay Selection (RS) can improve the performance in relaying networks separately. However, there is little work concerning their combination in multi-cell uplink scenarios. In this paper, we investigate the issue which considers the CA and RS to optimize the system transmission rate in an uplink scenario, while maintaining the re-source distribution fairness among users. This is first formulated as an optimization problem for a linear cellular system, where the same frequency channels can be reused in different cells. Based on the link and co-channel inter-ference conditions, two low-complexity CA and RS schemes are then proposed with dif-ferent decomposition sequences. Finally, nu-merical results are conducted to verify the effectiveness of the proposed CA and RS methods. Simulations results show that the proposed methods can yield significant im-provements in system performance in terms of average sum rate. 相似文献
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本文针对双跳全双工多中继系统,研究了在中继节点能量受限情况下的中继选择方案。在该文中,中继工作方式为放大转发(Amplify-and-Forward, AF),且中继通过收集源节点提供的能量来对源节点信息进行转发。整个通信过程分为两阶段,能量收集阶段与信息传输阶段,即采用的是时域分割方案。为了获得较好的性能与复杂度折中,本文分别研究了三种不同的中继选择策略,即最佳中继选择方案和两种次优中继选择方案。针对所提的三种方案,推导分析了其系统中断概率的理论值和下边界,以及系统的有效吞吐量。最后,利用蒙特卡洛仿真验证了理论分析的正确性,且仿真结果表明最佳中继选择方案的性能优于两种次优的中继选择方案,但其实现的复杂度高。 相似文献
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《无线电通信技术》2017,(6):1-4
针对无线中继网络中物理层网络编码技术的应用,分析验证了其所带来可观的吞吐量性能提升。总结了当前物理层网络编码技术的相关研究方向,归纳了通信理论研究、信息理论研究和网络理论研究三个方面。介绍了物理层网络编码的关键技术,对物理层网络编码技术在实际信道条件下的性能分析及改进、采用高阶调制时的检测模糊及改进、基于嵌套格码的计算-转发策略和结合缓冲中继协议设计进行了深入探讨。以期放宽物理层网络编码对信道模型的限制,拓展其适用条件,同时在保障通信过程可靠性的前提下充分发挥该技术对通信有效性的提升,从而推进物理层网络编码技术在实际无线中继通信系统中的应用。 相似文献
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通过对多用户对多个可选中继组成的双向中继网络进行权重二部图建模,并利用信道状态信息合理设计权重,从而将以最大化系统总速率为目标的中继和用户对选择策略问题等效为权重二部图的最大权匹配问题。利用图论最大权匹配算法(匈牙利算法),提出了最大权匹配选择策略。并进一步同时基于最大权匹配算法和用户对公平性,提出了最大权匹配轮询策略和基于数据序列因子的最大权匹配策略。仿真结果证明,3种策略均提升了系统性能。 相似文献
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本文以协同通信网络中继选择策略为研究对象,通过对协同通信及其中继选择技术基础、单源以及多源多中继网络自适应中继选择策略的分析,试图探索出相对完善的协同通信网络中继选择策略,推动协同通信网络中继系统的理论研究发展。 相似文献
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Relaying can replace one transmission over a long distance with several transmissions over shorter distances, and the total transmission power of mobile stations thus can be lower in the case of relaying. As such, the relaying concept and protocols in a cellular environment have been much discussed in the literature recently. We mathematically analyze the idea of uplink relaying schemes, using a simple model that represents their essential functions. In order to simplify our performance analysis, we assume that the originator of a packet sets the maximum number of hops to the base station to be 2. Our results indicate that the performance benefits of relaying are significant 相似文献
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传统双向中继(Two-way relaying,TWR)策略在信道和数据速率非对称性条件下性能较差。本文提出一种机会全双工/双向中继策略,提高无线中继系统在信道和数据速率非对称条件下的中断概率性能。以最优中断概率为准则,将机会全双工/双向中继策略建模为传输时间分配问题,给出了机会全双工/双向中继策略最优时间资源和中继功率分配方案。仿真结果表明,与传统的全双工中继(Full-duplex relaying,FDR)和双向中继(TWR)比较,所提策略能够获得更好的中断概率性能。 相似文献
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《IEEE transactions on information theory / Professional Technical Group on Information Theory》2009,55(3):944-951
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Slim Chaoui 《电信纪事》2016,71(11-12):677-689
This paper deals with bit error performance analysis of network-coded (NC) multiple access relay channels that operate in the decode and forward mode with error-prone relaying under quasi-static Rayleigh fading channels. It shows that the combination of channel coding and NC relaying can be regarded as a distributed coding scheme (DCS) if the error propagation problem is adequately addressed. For this purpose, methods based on NC soft information relaying (NC-SIR) and NC hard information relaying (NC-HIR) are investigated. In the framework of NC-SIR, the recently proposed Rayleigh-Gaussian log-likelihood-ratio-based Model is used for modelling the soft estimated symbols at the output of the relay soft encoder. The resulting scheme is referred to as NC-SIR-DCS. On the other hand, two NC-HIR-based schemes are studied and analyzed. The first employs automatic repeat request (ARQ) protocols between the relay node and each source node to ensure error-free propagation and is referred to as NC-ARQ-DCS, while the second performs a limiter function at the destination during iterative decoding as introduced in Thobaben (1) distributed and is referred to as NC-LFD-DCS. The SNR of the one-hop link, the equivalent to the sources-relay-destination links, is estimated in the case of NC-SIR-DCS and is lower bounded in the case of NC-LFD-DCS, while in the case of NC-ARQ-DCS, the average SNR cost per information bit due to the ARQ protocol is estimated. These processes allow tractable analysis of the bit error rate performances of the presented network-coded DCSs. Simulation results are carried out to assess the accuracy of the proposed bounds for different relay positions between source nodes and destination. 相似文献
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Adaptive Path Selection Scheme with Combining for Multiple Relaying Cooperative Communications Networks
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In future communications, cooperative communications with relay networks will be one of the most effective schemes to enlarge the coverage area and to boost the data rate. In the recent research results, the path selection, power allocation, and relay protocols on relay networks are the most important factors to improve the system performance. However, the channel quality of the direct transmission path and the relaying path has an influential effect on the performance of relay networks. Therefore, in this paper, we propose a best relaying path selection (BRPS) scheme to obtain the path diversity to improve the system capacity and data rate for cooperative networks (CNs). Simulation results show that the more the relay nodes are selected, the lower the bit error rate (BER) is. The proposed BRPS scheme obtains a high concession between both BER and system capacity for CNs. 相似文献
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物理层网络编码机会中继及中断性能分析 总被引:2,自引:1,他引:1
该文研究了频率非选择性瑞利衰落信道中的物理层网络编码系统容量问题。基于放大转发机制提出了一种基于最大最小互信息准则的机会中继策略。在瑞利衰落信道环境下,从双向通信的角度,通过理论分析得出其中断概率解析式,同时推导了理想物理层网络编码和传统直接传输系统的中断概率解析式。通过理论分析,发现在某些节点发射功率条件下,系统中断概率将完全取决于单向链路。在此基础上完成了数值仿真实验,结果表明所提策略的中断性能与理想物理层网络编码和传统直接传输相比有了显著的提高。 相似文献
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This paper presents a cooperative spectrum sharing protocol using non‐orthogonal multiple access in cognitive radio networks. A 2‐phase protocol comprising of a primary transmitter‐receiver pair and a secondary transmitter‐receiver pair is considered. In the proposed protocol, 3 data symbols can be transmitted during the 2 phases; this is unlike the traditional decode‐and‐forward relaying where 1 data symbol can be transmitted and the conventional superposition coding–based overlay spectrum sharing and the cooperative relaying system using non‐orthogonal multiple access where 2 data symbols can be transmitted, under a single‐relay scenario. We have investigated performance of our proposed protocol in terms of ergodic sum capacity and outage probability along with analytical derivations over independent Rayleigh fading channels. We also compared our proposed protocol with the traditional decode‐and‐forward relaying, conventional superposition coding–based overlay spectrum sharing, and the cooperative relaying system using non‐orthogonal multiple access schemes to demonstrate efficacy of the proposed protocol. The simulation and analytical results are presented to confirm efficiency of the proposed spectrum sharing protocol. 相似文献
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Modeling iCAR via Multi-Dimensional Markov Chains 总被引:2,自引:0,他引:2
iCAR is a new wireless system architecture based on the integration of cellular and modern ad hoc relaying technologies. It addresses the congestion problem due to limited channel access in a cellular system and provides interoperability for heterogeneous networks. The iCAR system can efficiently balance traffic loads and share channel resource between cells by using ad hoc relaying stations (ARS) to relay traffic from one cell to another dynamically. Analyzing the performance of iCAR is nontrivial as the classic Erlang-B formula no longer applies when relaying is used. In this paper, we build multi-dimensional Markov chains to analyze the performance of the iCAR system in terms of the call blocking probability. In particular, we develop an approximate model as well as an accurate model. While it can be time-consuming and tedious to obtain the solutions of the accurate model, the approximate model yields analytical results that are close to the simulation results we obtained previously. Our results show that with a limited number of ARSs, the call blocking probability in a congested cell as well as the overall system can be reduced. 相似文献
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Network coding (NC) is a technique that allows intermediate nodes to combine the received packets from multiple links and forwarded to subsequent nodes. Compared with pure relaying, using NC in a wireless network, one can potentially improve the network throughput, but it increases the complexity of resource allocations as the quality of one transmission is often affected by the transmission conditions of multiple links. In this paper, we consider an ad hoc network, where all the links have bidirectional communications, and a relay node forwards traffic between the source and the destination nodes using NC. All transmissions share the same frequency channel, and simultaneous transmissions cause interference to each other. We consider both digital NC and analog NC strategies, referred to as DNC and ANC, respectively, and schedule transmission time and power of the nodes in order to maximize the overall network throughput. For DNC, an optimum scheduling is formulated and solved by assuming that a central controller is available to collect all the link gain information and make the scheduling decisions. Distributed scheduling schemes are proposed for networks using DNC and ANC. Our results indicate that the proposed scheduling scheme for DNC achieves higher throughput than pure relaying, and the scheduling scheme for ANC can achieve higher throughput than both DNC and pure relaying under certain conditions. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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Hybrid automatic repeat request (HARQ) is a well-known technique for improving system throughput and link performance of wireless communication systems, including cooperative communication systems. The amplify-and-forward (AF) relaying method is one of the most attractive cooperative diversity schemes because of its low complexity. In this article, the end-to-end performance in terms of block error rate (BLER) and normalized throughput of AF relaying with HARQ transmission under the Rayleigh fading channel is analyzed. Numerical results validate the proposed analysis and demonstrate the gain of HARQ schemes in AF relaying systems. This analytical method can be extended to the systems with other HARQ protocols and other cooperative relaying schemes. 相似文献