无线多播中基于网络编码的高效重传方法研究
发布时间：2018-11-20 12:02
【摘要】：无线通信是物联网系统和移动互联网系统中最重要的通信方式之一。随着社会经济和科学技术的发展,信息化建设的不断推进和深入,无线通信和无线网络在各个领域的应用越来越广。多播是无线通信中最常用的数据传输方式之一。在无线多播通信中,由于无线信道容易受干扰及衰减、衰落等不可靠时变特性,常常导致较高的信道误码率,致使无线链路质量较差且稳定性较低,数据分组传输容易受损,严重影响了传输效率。为了提高无线传输的可靠性和传输效率,重传技术被广泛研究,成为无线多播通信中最主要的解决途径之一。其中,基于网络编码的无线重传技术因在吞吐量方面的优势,成为目前无线通信领域研究的一个热点课题。然而,无线多播重传中网络编码的引入带来了许多新的问题,比如编码方法、编码策略和编码时机等,迫切需要设计高效的编码策略以提高重传效率,并保障各种无线网络环境下编码重传的优越性能。在这样的背景下,本文基于联合优化、中继协作等思想,对无线多播中基于网络编码的高效重传方法进行了研究,其核心是在保持较低算法复杂度下,找到丢失分组的最优网络编码组合,通过最大化每次重传的增益来减少重传次数或最大化系统平均重传增益。本文的研究工作及贡献主要包括:1.较系统地研究并总结了基于网络编码的无线多播重传技术中采用的各种网络编码技术,包括其提出、演进及基本概念。从编码优化、解码优化、时延受限、链路质量加权等多个方面,对基于机会网络编码的重传技术的研究现状进行了较全面深入的研究和总结。这些内容有助于今后的研究者快速系统地了解课题技术背景。2.研究了编解码联合优化的无线多播重传方法以提高编码效率。根据编解码联合优化目标,研究了丢失分组的网络编码问题,提出了基于散列邻域关联搜索的机会网络编码重传方法。该方法采用“邻域关联搜索-多分组联合解码”机制。在编码优化方面,通过散列邻域关联搜索进一步挖掘最大可解码丢失分组组合之间的编码机会;在解码优化方面,除优先从满秩重传编码分组中恢复丢失分组外,允许接收节点从多个重传编码分组中恢复丢失分组。在保持较低的算法复杂度下,有效地减少了重传次数,提高了传输性能。在此基础上,为了提高重传编码分组的传输成功率,将实时无线链路质量引入到丢失分组编码组合的选择计算当中,提出了一种加权的丢失分组优化组合算法,使得编码增益最大且能让更多接收节点恢复其丢失分组的可解丢失分组组合被优先编码重传,从而进一步提高了传输效率。3.研究了信道突变、连续分组丢失等无线网络环境下的高效重传方法以提高传输效率。当某些接收节点因受到干扰出现信道突变导致与源节点之间的链路质量变差时,由源节点进行丢失分组重传,重传再丢失现象将非常严重,连续分组丢失将导致重传性能急剧下降。基于无线中继系统的协作重传思想,提出了基于网络编码的机会中继高效重传方法。该方法动态选择数据分组接收情况最好且信道质量优于源节点的接收节点作为机会中继,代替源节点进行其他接收节点的丢失分组重传,从而获得更好的重传性能。实时链路质量通过网络测量估计获得,机会中继选择基于分簇及就近合并原则。这种方法同样适用于某些接收节点处于“中继节点”位置的较好质量无线多播网络环境。与现有重传方法相比,该方法更好地利用了现有网络资源来提高传输效率,理论分析和仿真测试验证了其有效性。4.研究了连续动态网络编码重传方法以增加最优编码机会。针对批(块,代)内编码机制导致的编码机会浪费、单次重传效益无法最大化等问题,提出了基于机会网络编码的动态连续重传方法。该方法通过第一缓存数据分组连续传输和后续逐分组传输来保证充分的最优编码机会,每次仅重传丢失分组最优编码组合或满足特定条件的最大化编码组合,从而使得每次重传的增益最大化,并分别给出了非实时应用和实时应用场景的最大化丢失分组组合的重传条件。与现有重传方法相比,该方法对节点数据缓存没有特殊要求,容易实现时延控制,但连续编码增加了节点的处理负担,为此采用高效的散列汉明搜索来支持该方法。当接收节点数较少,发送数据缓存足够大时,该方法在重传效率上具有明显的优势。最后通过数学分析和仿真测试验证了该方法的有效性。
[Abstract]:Wireless communication is one of the most important ways of communication in an Internet of Things system and a mobile Internet system. With the development of social economy and science and technology, the continuous development and in-depth of information construction, the application of wireless communication and wireless network in various fields is becoming more and more wide. multicast is one of the most commonly used data transmission modes in wireless communication. in that wireless multicast communication, because the wireless channel is susceptible to non-reliable time-varying characteristics such as interference and attenuation, fading, and the like, the high channel error rate is often caused, so that the quality of the wireless link is poor and the stability is low, and the data packet transmission is easy to be damaged, and the transmission efficiency is seriously affected. In order to improve the reliability and transmission efficiency of the wireless transmission, the retransmission technology is widely studied and becomes one of the most important solutions in the wireless multicast communication. The wireless retransmission technology based on network coding has become a hot topic in the field of wireless communication. However, the introduction of the network coding in the wireless multicast retransmission brings many new problems, such as coding method, coding strategy and coding timing, etc., it is urgent to design efficient coding strategy to improve the retransmission efficiency and to guarantee the superiority of the coding retransmission in various wireless network environments. In this background, based on the idea of joint optimization and relay cooperation, this paper studies the method of efficient re-transmission based on network coding in the wireless multicast, the core of which is to find the optimal network coding combination of the lost packet under the complexity of keeping the lower algorithm. the number of retransmissions or the maximum system average retransmission gain is reduced by maximizing the gain of each retransmission. The research work and contribution of this paper mainly include: 1. The paper systematically studies and summarizes the various network coding techniques used in the wireless multicast retransmission technology based on network coding, including its development, evolution and basic concept. From the aspects of coding optimization, decoding optimization, time delay limited, and link quality weighting, the present situation of the retransmission technology based on opportunistic network coding is studied and summarized. these will help researchers to quickly and systematically understand the subject's technical background. The wireless multicast retransmission method with combined coding and decoding is studied to improve the coding efficiency. Based on the joint optimization goal of coding and decoding, the network coding problem of the lost packet is studied, and the method of opportunistic network coding and re-transmission based on the hash-column neighborhood association search is proposed. The method adopts a 鈥渘eighborhood association search-multi-packet combined decoding鈥，
本文编号：2344862
[Abstract]:Wireless communication is one of the most important ways of communication in an Internet of Things system and a mobile Internet system. With the development of social economy and science and technology, the continuous development and in-depth of information construction, the application of wireless communication and wireless network in various fields is becoming more and more wide. multicast is one of the most commonly used data transmission modes in wireless communication. in that wireless multicast communication, because the wireless channel is susceptible to non-reliable time-varying characteristics such as interference and attenuation, fading, and the like, the high channel error rate is often caused, so that the quality of the wireless link is poor and the stability is low, and the data packet transmission is easy to be damaged, and the transmission efficiency is seriously affected. In order to improve the reliability and transmission efficiency of the wireless transmission, the retransmission technology is widely studied and becomes one of the most important solutions in the wireless multicast communication. The wireless retransmission technology based on network coding has become a hot topic in the field of wireless communication. However, the introduction of the network coding in the wireless multicast retransmission brings many new problems, such as coding method, coding strategy and coding timing, etc., it is urgent to design efficient coding strategy to improve the retransmission efficiency and to guarantee the superiority of the coding retransmission in various wireless network environments. In this background, based on the idea of joint optimization and relay cooperation, this paper studies the method of efficient re-transmission based on network coding in the wireless multicast, the core of which is to find the optimal network coding combination of the lost packet under the complexity of keeping the lower algorithm. the number of retransmissions or the maximum system average retransmission gain is reduced by maximizing the gain of each retransmission. The research work and contribution of this paper mainly include: 1. The paper systematically studies and summarizes the various network coding techniques used in the wireless multicast retransmission technology based on network coding, including its development, evolution and basic concept. From the aspects of coding optimization, decoding optimization, time delay limited, and link quality weighting, the present situation of the retransmission technology based on opportunistic network coding is studied and summarized. these will help researchers to quickly and systematically understand the subject's technical background. The wireless multicast retransmission method with combined coding and decoding is studied to improve the coding efficiency. Based on the joint optimization goal of coding and decoding, the network coding problem of the lost packet is studied, and the method of opportunistic network coding and re-transmission based on the hash-column neighborhood association search is proposed. The method adopts a 鈥渘eighborhood association search-multi-packet combined decoding鈥，
本文编号：2344862
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