【作者】 唐舟进；

【导师】 龙鹏飞； 彭玉旭；

【作者基本信息】 长沙理工大学 ， 通信与信息系统， 2011， 硕士

【摘要】 空间分集或者说多天线分集技术因为能轻易地与其他分集技术(如时间分集和频率分集)结合起来,或者在其他分集技术无法应用时仍然能够为系统提供显著的增益,而得到了极大的关注。但在实现过程中,对体积、成本、功耗受限的移动终端要实现空间分集技术较为困难。相比起传统的多天线技术,在无线网络中,用户能够协同空闲的其他节点中继信息,以形成虚拟多天线系统来利用空间分集,在节点只能具备单天线的前提下能够提高系统性能和抗衰落能力。我们称之为协作通信。本文在相关研究的基础上,针对协作中继通信系统的一些关键技术进行了深入的研究。特别是对基于发射分集的多点协作通信系统,固定多天线中继节点网络和增量中继协议等方面取得一些进展。本文的主要工作如下:(4)提出了一种新的两跳多点中继协作通信系统模型,研究了在独立同分布Rayleigh衰落中采用选择解码转发协议的多点协作中继系统的误符号率和中断率性能。文中采用矩母函数分析方法,通过引入超几何函数,详尽推导出Rayleigh衰落信道下的多点合作通信系统的平均符号错误率和中断率的精确闭式表达式。通过蒙特卡洛仿真,验证了表达式的正确性。仿真结果显示两跳多点合作中继通信系统较之传统的合作系统拥有更好的性能。(5)基于固定多天线中继节点方案,研究了在指数相关同分布Nakagami-m信道环境下,多天线中继协作通信网络的性能。本文通过基于矩母函数(moment generating function, MGF)的方法推导了系统的中断率(outage probability, OP)和误比特率(bit error rate, BER)的闭式表达式。同时研究了中继节点所处位置对于系统性能的影响。(6)提出了一种基站调节的基于多用户分集的协作增量中继协议,在保持传统中继协议利用无线信道的广播特性通过两跳式的中继过程来产生多用户分集增益的特性外,还节省了信道资源有利于提高系统吞吐量。更多还原

【Abstract】 Space, or multiple-antenna, diversity techniques are particularly attractive as they can be readily combined with other forms of diversity, e.g., time and frequency diversity, and still offer dramatic performance gains when other forms of diversity are unavailable. It is difficult for mobile users to achieve MIMO techniques, these mobile terminals inability to equip-multiple antennas due to the constraints with the size,power or the cost,which also leads to new direction for application of MIMO.In contrast to the more conventional forms of multiple-antenna techniques, in wireless network, users can cooperate by relaying information for one another when they are idle, to form a virtual multiple-antenna system, thus achieving space diversity and enhancing the system performance and robustness to fading under the premise of using single antenna terminal. We refer to this form of communication as cooperative communication.On the basis of international current research works,this thesis investigates some key theories and technologies for cooperative communication systems in depth, and presents some new contributions in the following topics: Transmit diversity-based cooperative communication systems with Multi-point relays, Fixed multi-antenna relay network, incremental cooperative relaying protocol. The following contents are the main work in this thesis:(1) A two-hop multi-point cooperative relaying communication systems model is proposed and this thesis study the performance of Multi-point relaying cooperative communication systems using selection decode-and-forward relays over independent non-identical Rayleigh fading channel. Exact and closed-form expressions of average symbol error rate (SER) and outage probability with Rayleigh fading channels was firstly derived by means of the moment generating function (MGF) with hyper-geometric function. Simulation results shown that the expressions were valid and the performance of two-hop multi-points cooperative relaying communication systems was better than that of traditional cooperative communication system. (2) Performance of cooperative relaying employs infrastructure based fixed relays having multiple antennas has been investigated. Close form expressions for outage probability and bit error rate have been derived for Nakagami fading channels. The effect of fading correlation among relay antennas and relay positioning on the system performance have also been studied.(3) The paper propose a base-station coordinated cooperative multi-user diversity incremental relaying protocol, which uses the broadcast feature of the wireless channel to induce multi-user diversity through a two-phase relaying process and improve throughout by saving the channel resource.更多还原