认知双向中继网络性能分析与机会式传输方案研究

To achieve sustainable development of next-generation wireless communications industry, improving transmission reliability and spectrum efficiency must be addressed. Cognitive two-way relaying network (TWRN) by integrating two-way relaying technique into cognitive radio systems not only broadens network coverage, achieves diversity gain against large and small-scale fadings, but also sheds new light on higher spectral efficiency. Theoretical perforamnce analysis and transmission scheme design provide the basis for evaluation of system performance, and even the foundation to optimize the system performance and design system. Compared with conventional TWRN, there are more constraints in cognitive TWRN, such as transmit power constraints and co-channel interference, which make its theoretical analysis and transmission scheme design more difficult and challenging. Furthermore, because it is a relatively new field of research, the study of this aspect is very few in academe. This research project aims at the teoretical performance analysis and transmission scheme design including the following two critical problems: (1) performance analysis under Rayleigh/Nakagami-m fading channels,such as outage probability, average symbol error rate (SER) or bit error rate(BER) and capacity and so on; (2) opportunistic transmission scheme design under Rayleigh/Nakagami-m fading channels, such as opportunistic source transmission, opportunistic relay transmission and joint opportunistic source-relay transmission.

提高传输可靠性和频谱效率，是下一代无线通信产业要实现可持续发展必须解决的问题。把双向中继技术和认知无线电技术相融合，构成认知双向中继网络，不但能拓宽网络覆盖范围、实现分集增益以抵抗大小尺度衰落，还能提高频谱效率。性能分析和传输方案设计乃是评估、优化系统性能和实施系统设计的重要基石。相比传统双向中继网络，认知双向中继网络存在更多的约束条件，如共道干扰和发射功率约束，其性能分析和传输方案设计难度更大、更具挑战性；而其是一个比较新的研究领域，目前相关研究成果较少。本课题拟致力于解决认知双向中继网络的性能分析和传输方案设计问题，主要包括：（1）Rayleigh/Nakagami-m衰落环境下理论性能研究，如中断概率、平均误符号率/误比特率、遍历容量等；（2）Rayleigh/Nakagami-m衰落环境下机会式传输方案研究，如机会信源传输、机会中继传输和联合机会信源-中继传输等方案。

提高传输可靠性和频谱效率，是下一代无线通信产业要实现可持续发展必须解决的问题。认知双向中继网络，不但能拓宽网络覆盖范围、实现分集增益以抵抗大小尺度衰落，还能提高频谱效率。针对认知中继网络，项目组获得主要成果如下：.研究了其在衰落环境下的系统性能，获得中断概率的理论表达式及在高SNR区域的渐进结果，如Nakagami-m, Rayleigh, η-µ等衰落环境；研究了机会式传输方案设计，获得了其在多用户调度、中继选择等传输方案下系统的中断概率等性能；.研究了基于能量采集的认知DF、AF中继网络的中断性能；研究了大规模双向中继网络在Rayleigh, Rician信道下，在已知完备/不完备信道状态信息（CSI）下，系统的频谱效率和能量效率性能。