应对OCSI的单中继与多中继选择及功率分配方法

发布时间：2018-01-20 21:55

本文关键词： 协作通信中继选择功率分配过时信道状态信息中断概率　出处：《广西师范大学》2017年硕士论文　论文类型：学位论文

【摘要】：近些年,随着第四代移动通信的普及与第五代移动通信的提出,无线通信网络成为一大研究热点。协作分集是无线通信中对抗多径衰落的有效方法,不仅可以提高信息传输的可靠性,而且可以减少系统功率损耗。在协作通信中,通过引入中继节点形成虚拟MIMO系统协助源节点与目的节点进行通信,并利用中继选择技术从中选择一个或多个最佳中继节点用于信息传输,在目的节点处,采用最大比合并技术对分集信号进行处理。目前,大部分协作中继选择方法利用过时的信道状态信息(OCSI,Outdated Channel Status Information)进行中继选择,这将会严重恶化协作通信系统的性能,而信道预测可大大改善延时信道带来的影响。基于此,本文开展了应对OCSI影响的协作中继选择及功率分配方法研究,取得了以下进展:首先,已有的考虑OCSI的中继选择与功率分配方法往往只考虑源节点S到中继节点R之间链路或者中继节点R到目的节点D之间链路,实际上S-R与R-D两条链路信道状态信息都存在延时的问题。本文在充分考虑通信两条链路都存在延时信道状态信息的基础上,通过Bayesian估计准则的最小均方误差(MMSE)估计方法,预测数据传输时刻的信道增益,并通过Max-min预测信道增益进行中继选择。同时,在系统总功率一定的情况下,依据预测信道增益,提出了一种简单有效的优化功率分配方法,并与平均功率分配方法对比分析验证中断概率性能。通过仿真验证,本章所提的Max-min预测信道增益中继选择与优化功率分配方法在提高通信系统中断性能方面有有一定优越性。其次,在信道条件差的情况下,仅仅选择一个中继节点所实现的通信效果并不佳,需要选择多个中继节点参与协作,同时在系统总功率一定的情况下,优化源节点与被选中继节点之间的功率分配。在前述研究基础上,通过设置系统容量增益门限,将所述单中继选择扩展为多中继选择,同时优化多个中继节点与源节点之间的功率分配。仿真结果表明,在系统总功率一定的情况下,多中继选择较单中继选择系统中断性能更优,优化后的功率分配较等功率分配时的中断性能更优。
[Abstract]:In recent years, with the popularity of 4th generation mobile communication and the fifth generation mobile communication, wireless communication network has become a research hotspot. Cooperative diversity is an effective method to combat multipath fading in wireless communication. It can not only improve the reliability of information transmission, but also reduce the power loss of the system. In cooperative communication, a virtual MIMO system is formed by introducing relay nodes to facilitate the communication between the source node and the destination node. And the relay selection technology is used to select one or more optimal relay nodes for information transmission. At the destination node, the maximum ratio combination technique is used to process the diversity signal. Most cooperative relay selection methods utilize outdated channel state information for OCSI. Outdated Channel Status Information makes relay selection, which seriously degrades the performance of the cooperative communication system. The channel prediction can greatly improve the impact of the delay channel. Based on this, the cooperative relay selection and power allocation methods to deal with the impact of OCSI are studied in this paper, and the following progress has been made: first. The existing relay selection and power allocation methods considering OCSI usually only consider the link between source node S and relay node R or between relay node R and destination node D. In fact, both S-R and R-D link channel state information has the problem of delay. In this paper, we consider that both links have delay channel state information. The channel gain at the time of data transmission is predicted by the minimum mean square error (MMSE) estimation method of the Bayesian estimation criterion. At the same time, a simple and effective optimal power allocation method is proposed according to the prediction of channel gain under the condition of the total power of the system. The outage probability performance is compared with the average power allocation method and verified by simulation. In this chapter, the Max-min predictive channel gain relay selection and optimized power allocation method have some advantages in improving the interrupt performance of communication systems. Secondly, in the case of poor channel conditions. It is not good to select only one relay node, so it is necessary to select more than one relay node to participate in the cooperation, and at the same time, the total power of the system is fixed. The power allocation between the source node and the selected successor node is optimized.; on the basis of the above research, the single-relay selection is extended to multi-relay selection by setting a system capacity gain threshold. At the same time, the power distribution between multiple relay nodes and source nodes is optimized. The simulation results show that the multi-relay selection is better than the single-relay selection system when the total power of the system is fixed. The optimized power allocation is better than the same power allocation.
【学位授予单位】：广西师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN92

【相似文献】