衰落信道中无线中继技术的分析与性能评估

发布时间：2018-08-09 20:37

【摘要】：随着无线电系统不断的加速发展,无线用户对高可靠性、高速度、大容量的需求越来越迫切。无线协作通信根据无线通信的广播特性在独立的单个天线上构造虚拟天线阵列进行通信。当空间上分隔的独立天线终端进行合作时,多天线技术的一系列重要优点就会体现出来,比如分集增益,以及总是存在的从源节点到目的节点的路径。大量的研究工作表明,协作分集的使用能够为传输半径、容量和可靠性带来重大的潜在优势。在恶劣的情况下,信号的传输很难达到高吞吐量和低误符号率。为了解决这个问题,研究人员提出了大量的协作策略,其中,中继是改善信道容量和增强传输可靠性的主要方法。当前关于协作通信的大部分工作都集中在一个利用放大、转发(Amplify and Forward, AF)或者解码、转发(Decode and Forward, DF)的协议上。在前一类协议中,中继节点对接受信号进行放大并转发,而后一种协议下,中继节点对接受信号进行解码并转发。同时,研究者们对这种协作系统中的中断概率性能做了评估。当中继节点不能对接受信号进行连续正确地解码时,DF协议的性能将会降低,而当中继节点对接收到的含噪声的信号进行放大并转发时,AF协议的性能也将受到损失。但是根据现有研究,目前基本上还没有学者研究多中继时的中继协议选择。本文第一部分提出了一种如何选择AF协议或DF协议的方法(ORPS),并给出了这种方法相比现有协议的优势。中继采用如下策略持续工作：当中继可以对接收到的信号进行完全正确的解码时,该中继解码并转发该信号；当中继不能正确解码信号时,剩余的中继将在空闲周期内放大并转发信息。这样,中继节点可以根据本文提出的ORPS来高效地转发从源节点到目的节点的信号。在此基础上,本文对比了ORPS策略和仅使用单一AF协议时的误符号率(SER)性能进行了比较。结果表明：相对于只采用AF方式的协议,ORPS策略表现出了相当优异的性能,拥有约2dB的优势。更重要的是,本文提出的机制达到了满分集增益。在ORPS策略的基础上,本文进一步研究了当中继节点受到相邻节点的同频干扰问题,其中,干扰信号是其他发送节点同其目的节点通信时产生的。本文对不同中继及不同干扰功率下的ORPS策略和DF协议进行了对比。
[Abstract]:With the rapid development of radio system, the demand of wireless users for high reliability, high speed and large capacity is more and more urgent. Wireless cooperative communication constructs a virtual antenna array on a single antenna according to the broadcast characteristics of wireless communication. When spatially separated independent antenna terminals cooperate a series of important advantages of multi-antenna technology such as diversity gain and the path from source node to destination node always exist. A large number of studies have shown that the use of cooperative diversity can bring significant potential advantages for transmission radius, capacity and reliability. Under bad conditions, it is difficult to achieve high throughput and low symbol error rate. In order to solve this problem, researchers put forward a large number of cooperative strategies, among which relay is the main method to improve channel capacity and enhance transmission reliability. Most of the current work on cooperative communication focuses on a protocol that utilizes amplification, forwarding (Amplify and Forward, AF) or decoding, forwarding (Decode and Forward, DF). In the former protocol, the relay node amplifies and forwards the received signal. In the latter protocol, the relay node decodes and forwards the received signal. At the same time, the researchers evaluated the outage probability performance in the collaboration system. When the relay node can not decode the received signal continuously and correctly, the performance of the DF protocol will be degraded, and the performance of the AF protocol will also be lost when the relay node amplifies and forwards the received noise-contained signal. However, according to the existing research, there are no scholars to study the relay protocol selection for multi-relay. In the first part of this paper, we propose a method of choosing AF protocol or DF protocol, (ORPS), and give the advantages of this method compared with the existing protocol. The relay continues to work as follows: when the relay can decode the received signal correctly, the relay decodes and forwards the signal; when the relay fails to decode the signal correctly, The rest of the relay will amplify and forward the information during the idle period. In this way, the relay node can transmit the signal from the source node to the destination node efficiently according to the ORPS proposed in this paper. On this basis, the performance of ORPS strategy is compared with that of (SER) with only single AF protocol. The results show that compared with AF protocol, ORPS has excellent performance and has the advantage of about 2dB. More importantly, the proposed mechanism achieves full diversity gain. Based on the ORPS strategy, this paper further studies the co-frequency interference between the relay nodes and the adjacent nodes, where the interference signals are generated when the other transmitting nodes communicate with their destination nodes. In this paper, the ORPS strategy and DF protocol under different relay and different interference power are compared.
【学位授予单位】：华中科技大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TN92

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