利用似然比门限转换的自适应机会协作策略  

Dynamic opportunistic cooperative strategy with log likelihood ratio switching threshold

作　　者：成聿伦[1,2] 杨龙祥[1,2] 

机构地区：[1]无线通信江苏省重点实验室(南京邮电大学),南京210003 [2]宽带无线通信与传感网技术教育部重点实验室(南京邮电大学),南京210003

出　　处：《计算机应用》2013年第10期2715-2718,2738,共5页journal of Computer Applications

基　　金：国家973计划项目(2013CB329104);国家自然科学基金资助项目(61071090;61171093;61372124);江苏省高校自然科学基金重大项目(11KJA510001);江苏省高校研究生科研创新计划项目(CXZZ11_0388);国家科技重大专项(2011ZX03005-004-003);江苏973计划项目(BK2011027)

摘　　要：基于解码前传的错误传播严重影响机会协作系统的选择分集增益。针对此问题,提出一种基于似然比门限转换的自适应机会协作策略:最优中继采用似然比对接收信号质量进行指示,通过与基于链路误比特率的门限值比较,动态地选择中继方式,以保证中继链路得到充分利用。推导了平均误比特率的近似解析表达式,在此基础上对门限进行了优化。采用蒙特卡罗仿真验证了理论公式的有效性,仿真结果表明,当误比特率为0.001时,相比传统方案,该算法能节省1.2 dB的功率。Error propagation seriously degenerates the selection diversity of decode-and-forward-based opportunistic cooperative system. Addressing this problem, a Log Likelihood Ratio （LLR） -based adaptive switching scheme was proposed, which aimed at exploiting relay channel more efficiently through dynamic cooperation selection according to the LLR comparison with Bit Error Ratio （BER） -based threshold at relay. Moreover, the closed-form expression of the average BER was derived, and the threshold was optimized accordingly. Monte-Carlo simulations validate the analysis, and the results show that the proposed algorithm achieves 1.2 dB power gain at BER of 0.001, compared to the conventional scheme.

关 键 词：机会协作 自适应 似然比 选择分集 误比特率 

分 类 号：TN911.6[电子电信—通信与信息系统]