【作者】 吴宇平；

【导师】 赵旦峰；

【作者基本信息】 哈尔滨工程大学 ， 通信与信息系统， 2013， 博士

【摘要】 无线通信技术的进步带来了更快和更优质的网络访问服务。但是，技术的发展是与用户更快、更便宜、更稳定的无线通信的需求相匹配的。为了能够符合未来无线通信的需求，我们需要从功率、延迟、带宽等方面来提高无线通信的有效性，从而使其能够提供更高速率的、更好服务质量的多媒体业务。针对上述需求，可将信道编码技术、网络编码技术及协作分集技术相结合，提高无线通信系统的有效性、可靠性及吞吐量。在协作通信系统的中继节点采用网络编码技术，中继节点不仅转发信息，还能对信息进行相应的信号处理，通过网络编码可提高无线通信系统的容量及频带利用率；同时，协作通信系统采用信道编码技术，可提高系统的可靠性。将信道编码-网络编码联合设计技术应用到无线协作通信系统中，不仅可提高无线协作通信系统的容量，且可改善系统的纠错性能，因此对该技术进行研究具有重要的理论及实践意义。论文针对无线协作通信系统中的联合信道编码-网络编码技术进行了深入的研究，主要研究成果如下：首先，研究了中继转发模式、网络编码算法、编码协作通信系统方案等协作通信系统中的相关技术，并进行了相应的理论分析与仿真分析。在此基础上对无线通信系统中典型的信道纠错码技术，即卷积码、Turbo码及LDPC码的编译码算法进行了研究，并应用Matlab对影响上述三种信道编码性能的因素进行了仿真分析。其次，针对多源中继协作通信系统，提出了一种卷积码与网络编码的联合编码方案，该方案在中继节点对接收到的多个信源节点的信息进行卷积码编码，然后将编码后的码字进行网络编码转发，目的节点进行联合迭代译码恢复多个信源节点的信息，该方案随着源节点数量的增加，误码率性能得到显著的提高。针对双向中继信道，对卷积码-网络编码的联合迭代译码算法进行了研究，即全状态译码算法及简化状态译码算法，并对这两种译码算法进行了推导及分析，简化状态译码算法与全状态译码算法相比，可在尽量不损失编码增益的情况下，降低译码运算复杂度。再次，基于分集Turbo码思想提出了二源中继协作通信系统中“CTC码-网络编码的联合编码方案一”，该方案具有较小的译码时延、更强的纠错性能，对于源节点来说，不仅提高了码率，而且降低了源节点直接采用CTC编码算法的复杂度。针对“CTC码-网络编码的联合编码方案一”只适用于中继能够完全正确译码的协作通信系统，且中继节点和信宿端的接收天线只有一副的情况，同时没有充分利用信息间的相关性进行联合迭代译码的问题，作者进行了进一步的研究。随后提出了“CTC码-网络编码的联合编码方案二”，即适合于多址中继通信系统的CTC码-网络编码的联合编码方案，该方案考虑到中继可能存在不能正确译码信源信息的情况，信宿可以有选择的选择合适的先验信息进行译码，充分利用多址信息之间的相关性，进行联合迭代译码，并对联合迭代译码算法进行了详细的推导。仿真结果表明该方案具有较强的纠错性能，同时随着中继节点和目的节点接收天线的增多，系统的纠错性能也随之增强，从而表明该方案广泛适用于多址中继信道环境中。最后，基于网络编码与信道编码协作思想，提出了一种适用于多源协作通信系统的LDPC码-网络编码的联合编码方案，在该方案中不同信源节点的信息发送到中继点后进行LDPC编码，然后将编码后的码字进行网络编码转发，目的节点进行联合迭代译码恢复多个信源节点的信息，仿真结果表明该方案随着源节点数量的增加，多源协作通信系统的误码率性能显著提高。同时针对系统中使用的LDPC码，提出了一种改进的校验矩阵构造算法，即改进的PS构造算法，仿真结果表明该改进算法较原算法的误码率性能有显著提高。更多还原

【Abstract】 The advances in wireless communication technology bring faster and more affordableaccess to the network access services. However, the development of the technology needs tomeet the user’s faster, cheaper and more stable demand for wireless communications. In orderto be able to meet the future needs of the wireless communication, we need to improve theeffectiveness of wireless communication from power, delay, bandwidth, thus providing higherspeed, better quality of service multimedia services. According to these needs, the channelcoding technology, network coding technology and cooperative diversity technology can becombined to improve the validity, reliability and throughput of wireless communicationsystems. In cooperative communication systems, the relay nodes can forward information andachieve signal processing of the information, and also can be to maximize the capacity andthe bandwidth efficiency of the wireless communication system by network codingtechnology; In the same time, the reliability of the system can be improved by using channelcoding technology in cooperative communication systems. Through the applications of jointchannel coding and network coding technology, the capacity and the error correctionperformance of the system is improved, therefore, the study on this technology has importanttheoretical and practical research significance.Specifically, this dissertation mainly investigates the applications of joint channel codingand network coding technology in wireless communication systems. The main contribution ofour works can be summarized as follows:Firstly, the dissertation studied the key technologies in cooperative communicationsystems, such as relay forwarding mode, network coding algorithm, coding cooperativecommunication system schemes, and respectively given the theoretical analysis andsimulation analysis; On this basis, the dissertation studied encoding and decoding algorithmsof typical error correction codes technologies(i.e. convolutional codes, Turbo codes, LDPCcodes), and given the simulation analysis results of three kinds of channel codes.Secondly, the dissertation proposed a cooperative diversity scheme of jointConvolutional code(CC) coding and network coding applicable to multi-source cooperativecommunication system. This scheme conducts CC encoding for information of multiple source nodes received at relay node, and then forwards the encoded code words after networkcoding, after that destination node carries out joint iterative decoding to recover theinformation of multiple source nodes. The result of simulation showed that the bit error rate(BER) performance of multi-source cooperative communication system in this scheme isremarkably improved with increase of the number of source nodes; Meanwhile, thedissertation studied the CC-network coding joint iterative decoding algorithm for two-wayrelay channel, i.e. full-state trellis decoding algorithm and reduced-state trellis decodingalgorithm, derived the two kinds of decoding algorithms, the reduced-state trellis decodingalgorithm compared with the full state trellis decoding algorithm, in the case as far as possiblewithout loss of coding gain, significantly reduced the complexity of the decoding operation.Then, a new scheme of joint design of network coding and channel coding based on theidea of diversity Turbo codes was proposed, that was the joint design of convolutional Turbocode(CTC) and network coding scheme1. This scheme has smaller decoding delay, strongererror correction performance, and for source nodes, not only improve the rate, but also besimpler than direct application of the CTC encoding algorithm. Meanwhile, according to thedefects of the above-mentioned schemes, such as, it is only suitable for application in thecooperative communication system with the case of completely correct decoding in the relaynodes, and has only one receiving antenna in relay nodes and sink nodes, meanwhile notmakes full use of the correlation of informations in the joint decoding process. Therefore, theauthors conducted a further study, and subsequently proposed joint design of CTC andnetwork coding scheme2for multiple access relay channel. This scheme consider that therelay may not correctly decode the source information, the destination can select theappropriate choice of a priori information for decoding. Simulation result shows this schemehas stronger error correction performance and more suitable for harsh communicationenvironment, in addition, with the increase of relay and destination’s receiving antenna, theerror correction performance of the system increases as well, in other words, the proposedscheme can be widely used in the multiple access relay channel environment.Finally, based on the research on channel coding and network coding in cooperativerelay communication system and in allusion to LDPC channel coding with excellentperformance, the dissertation presented a joint design scheme of LDPC coding and networkcoding specific to multi-source cooperative communication system, the result of simulation indicates that the BER performance is remarkably improved with increase of the number ofsource nodes; meanwhile the dissertation proposed an improved check matrix structurealgorithm, i.e. improved PS structure algorithm, The result of simulation shows that LDPCcodes constructed by the improved check matrix structure method proposed in thisdissertation have greater coding gain.更多还原