无线协作传输策略及其性能的研究

发布时间：2018-11-03 07:10

【摘要】：衡量一个通信系统性能优劣主要是考察其有效性、可靠性和安全性这三方面性能。与有线通信相比,无线通信在有效性、可靠性和安全性方面面临更为严峻的挑战：一方面,多径衰落效应将导致接收信号畸变、信噪比较低,从而影响信息传输有效性和可靠性：另一方面,无线信道的开放性将导致传输信息易被窃听器截获,从而使得信息传输的安全性降低。近年来,MIMO技术和协作通信技术被认为是改善和提高无线通信系统这三方面性能的有效手段,受到学术界和产业界的广泛关注和深入研究。无线协作通信技术的核心研究内容是设计有效的协作传输策略,使得无线通信系统在有效性、可靠性或者安全性方面的性能得到明显的改善。众所周知,复用增益与分集增益分别是评价MIMO无线通信系统有效性和可靠性的性能指标。已有的研究表明,复用增益和分集增益之间是此消彼长的关系,即高复用增益会导致较低的分集增益,反之亦然；分集复用折中(DMT)正是反映了分集增益和复用增益之间的这种折中关系。因此,通过分析DMT性能来评估协作传输系统有效性和可靠性是一个合理的选择。另外,衡量传输系统安全性的性能指标通常采用“安全速率”,其含义是授权用户能正确解码、而窃听器不能解码的信息传输速率。本文针对几种典型的无线协作通信场景,研究基于DMT优化或者安全速率优化的无线协作传输策略。在对抗多径衰落方面,设计更为有效的多中继协作传输策略,优化系统的DMT性能；在对抗窃听方面,设计更为有效的混合式协作传输策略,达到更大的安全速率。本文主要研究内容与贡献如下： 1)对于多中继点对点信道模型,提出了一种基于中继复用的协作传输策略。该策略的基本思想是用两个半双工中继模拟一个全双工中继,克服中继的半双工限制；另外,该策略融合了分层中继选择和线性迫零算法,其中分层中继选择保证了最优的分集增益,而复杂度较低的迫零算法用于消除中继间干扰。理论分析和Monte Carlo仿真实验表明该策略能优化系统的DMT性能,并且能逼近多输入单输出(MISO)系统的最优上界。 2)对于多中继多接入信道模型,提出了一种基于叠加编码和中继复用的协作传输策略。该协作策略的特点是保证每个源信息能在各个源端以及中继上被发送,从而实现源端之间以及源端与中继之间的完全协作,从而达到该系统的最优分集增益。理论分析和Monte Carlo仿真实验表明,该策略能优化系统DMT性能,并且能逼近最优MISO系统的上界。 3)对于中继窃听信道,提出了三种混合式协作传输策略：基于有噪网络编码(NNC)的策略、基于部分解码前传(PaDF)的策略、基于人工状态(AS)的策略。第一种协作策略融合了NNC压缩前传技术和干扰协助技术,其中的NNC压缩前传技术是为了提升授权用户间的通信能力,而干扰协助技术是为了抑制窃听信道,从而达到帮助主信道、同时抑制窃听信道的效果。第二种协作策略利用叠加编码、反向解码等基本编解码方法,融合部分解码前传技术和噪声前传技术,以提升授权用户间的通信能力、同时抑制窃听信道。第三种协作策略融合了人工状态和噪声前传技术,其中的人工状态是由源端产生,它联合中继产生的干扰信息可以有效地抑制窃听信道,而不对目的端产生任何损害。这种协作策略的特点是中继不接收任何源端信息,因而不受源端到中继信道质量的影响。另外,针对高斯中继窃听信道,对以上三种协作传输策略作了具体的设计,并利用信息论安全基础理论分析了它们的可达安全速率。理论分析和数值结果均表明所提协作策略可以提升系统的安全性能。 4)对于具有“会议”的多接入窃听信道,提出了一种基于Willems编码的混合式协作传输策略。其基本思想是融合Willems编码和Wyner的随机盒子技术,既可以通过“会议”链路提升源到目的端的通信能力,又能通过多接入窃听信道抑制窃听器的窃听能力。另外,利用信息论安全基础理论分析了该策略的可达安全速率域以及安全容量域的外界。基于以上所提协作策略,并针对高斯多接入窃听信道,设计了两种具体实现方案：基于多路复用的方案和基于协作时分多址接入的方案。理论分析和数值计算结果表明,源端之间的“会议”链路能有效提升系统安全性以及各个源端的安全速率。
[Abstract]:The performance of a communication system is mainly based on its effectiveness, reliability and safety. Compared with wired communication, wireless communication faces more serious challenges in the aspects of validity, reliability and security: on the one hand, the multi-path fading effect will lead to the distortion of the received signal and the signal-to-noise ratio is low, thus affecting the validity and reliability of information transmission: on the other hand, the openness of the wireless channel will cause the transmission information to be easily intercepted and thus the security of the information transmission is reduced. In recent years, MIMO technology and cooperative communication technology are considered to be an effective means to improve and improve the performance of wireless communication system. The core research content of wireless cooperative communication technology is to design effective cooperative transmission strategy, so that the performance of wireless communication system in validity, reliability or security is obviously improved. As is well known, the multiplexing gain and diversity gain are the performance of evaluating the effectiveness and reliability of the MIMO wireless communication system, respectively. The existing research shows that the relationship between the multiplexing gain and the diversity gain is the relationship between the diversity gain and the diversity gain, that is, the high multiplexing gain can lead to lower diversity gain, and vice versa; and the split-set multiplexing trade-off (dmt) is the compromise between the diversity gain and the multiplexing gain. Therefore, it is reasonable to evaluate the effectiveness and reliability of the cooperative transmission system by analyzing the performance of dmt. Select. In addition, measure the performance index of the transmission system security Always use "security Rate", the meaning of which is to authorize the user to decode correctly, and the stolen information can not be decoded Rate. Based on several typical wireless collaborative communication scenarios, a wireless co-association based on dmt optimization or security rate optimization is investigated. As a transmission strategy, a more efficient multi-relay cooperative transmission strategy is designed to optimize the performance of the system in the aspect of multi-path fading, and a more efficient hybrid cooperative transmission strategy is designed in the aspect of anti-wiretapping, so as to achieve greater efficiency. Security rate. The main contents of this paper The contribution is as follows: 1) For multi-relay point-to-point channel model, a relay complex is proposed The basic idea of the strategy is to simulate a full-duplex relay with two half-duplex relay to overcome the half-duplex limitation of the relay; in addition, the strategy combines the hierarchical relay selection and the linear forcing zero algorithm, wherein the hierarchical relay selection guarantee Optimal diversity gain and low complexity forced-zero algorithm The theoretical analysis and Monte Carlo simulation experiments show that the strategy can optimize the performance of the system, and can approximate multi-input single-output (MISO). (2) For multi-relay multi-access channel model, a kind of superposition coding is proposed. The cooperative strategy is characterized in that each source information can be transmitted on each source end and the relay so as to realize the complete cooperation between the source end and the source end and the relay, and therefore, Theoretical analysis and Monte Carlo simulation experiments show that the strategy can optimize the performance of the system and can be approximated On the basis of the strategy of noisy network coding (NNC), the strategy based on partial decoding (PaDF) is proposed. According to the strategy of artificial state (AS), the first collaboration strategy combines the NNC compression pretransmission technology and the interference assistance technology, and the NNC compression pre-transmission technology is in order to improve the communication capability among the authorized users, and the interference assistance technology is to suppress the tap channel so as to reach the help of the master. the second cooperative strategy utilizes the basic encoding and decoding methods such as superposition coding, reverse decoding and the like, and the fusion part decodes the pre-transmission technology and the noise pre-transmission technology so as to improve the authorized users. the third cooperation strategy combines the artificial state and the noise pre-transmission technology, the artificial state is generated by the source end, the interference information generated by the joint relay can effectively inhibit the wiretap signal, Channel, without any damage to the destination, is characterized by the fact that the relay does not receive any source end information, and thus It is not affected by the quality of the source end to the relay channel. In addition, the above three cooperative transmission strategies are specially designed for the Gauss relay wiretapping channel, Theoretical analysis and numerical results show that they can reach the safe rate. the proposed collaboration strategy can promote Security performance of the system. 4) For multi-access wiretapping channels with "conference", a kind of base is proposed. A hybrid collaboration transmission strategy encoded by Willems. Its basic idea is to fuse Willems Code and W yner's random box technology allows both the source-to-destination communication capability to be raised through the & quot; conference & quot; link, and It can suppress the tapping ability of the bug through the multi-access interception channel. In addition, the basic theory of the system security is used to analyze the problem. The strategy can reach the secure rate domain and the outside of the secure capacity domain. multiplexing-based scheme and cooperative time division multiple access based connection Programme of admission Theoretical analysis and numerical calculation results show that the "meeting" between the source ends
【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TN92

【相似文献】