合作通信中的合作用户选择方案

User Selection Strategies in Cooperative Communication

合作通信(又称合作分集)技术是一种新的空间分集技术。该技术通过用户之间共享天线构成虚拟天线阵列。对比于传统的多天线系统(MIMO),并不要求用户终端配备多根天线,大大降低了用户终端的设计复杂度和成本。合作通信协议的设计一直是该领域的热点问题,本文重点讨论合作用户的选择方案。首先简要介绍两种常见的合作用户选择方案:对称和非对称合作方案。其次,从中断概率、SNR增益、分集和复用折中、位置偏差影响等多方面对这两种合作用户选择方案进行了详细的分析和比较。最后根据分析和比较的结果,讨论这两种方案各自的应用场合。

Cooperative communication （or cooperative diversity） is a new spatial diversity technique. Users share their antennas to construct the virtual antenna array. Compared to traditional MIMO systems, cooperative communication does not need multiple antennas at terminal devices, and therefore significantly reduces the implemental complexity and cost. This paper considers cooperative user selection schemes. In particular, we compare the symmetric and asymmetric cooperation schemes in several aspects including outage probability, signal-to-noise ratio （SNR） gain, diversity and multiplexing tradeoff, and impacts of position deviation. Based on the comparison, we discuss how to choose the cooperation scheme with respect to actual application background.