TDD中继系统下行链路自适应方法  

Downlink adaption scheme for TDD relay-enhanced systems

作　　者：朱元萍[1,2,3] 林文佳[1,2,3] 杨馨[1,2,3] 

机构地区：[1]中国科学院上海微系统与信息技术研究所,上海200050 [2]上海无线通信研究中心,上海200335 [3]中国科学院无线传感网与通信重点实验室,上海200050

出　　处：《计算机工程与设计》2012年第3期841-846,共6页Computer Engineering and Design

基　　金：上海市科技启明星计划基金项目(10QA1406300);上海市重点基金项目(10511500404);上海市国际合作基金项目(10220712100)

摘　　要：为了解决3GPP LTE-A系统中Type-Ⅱ中继不发送下行参考信号导致基站无法获得中继到用户之间的链路质量信息、无法合理选择下行数据调制编码格式的问题,提出了一种TDD中继系统中新的下行链路自适应方法。该方法利用TDD系统上下行信道互惠性和UE周期性发送的上行探测信号更准确的进行信道估计,继而选择更合适的调制编码格式。给出了工作过程及发送接收算法模型,并进而提出基站与中继协作地采用发送分集技术传输下行数据。仿真实验结果表明,新的链路自适应方法及基站与中继发送分集的传输方式,显著地提高了系统频谱利用率。To deal with the problem that eNB cannot select appropriate modulation and coding scheme for downlink transmission without knowledge of relay-UE link quality since Type-Ⅱ relay does not transmit common reference signal in a 3GPP LTE-A sys- tem, a novel downlink adaption scheme for TDD relay-enhanced system is proposed. This scheme utilizes the reciprocality of downlink and uplink channel in TDD system and the uplink sounding signal which is send periodicity by UE to estimate channel more accurately, and then select more appropriate modulation and coding scheme. The proposed scheme＇s procedure, transmit and receive algorithms are also presented. Furthermore, it is proposed that eNB and relay cooperatively employ transmit diversity for downlink transmission. Simulation results show that proposed link adaption scheme with cooperative transmit diversity im- proves system spectrum efficiency significantly.

关 键 词：中继 链路自适应 自适应调制编码 发送分集 频谱利用率 

分 类 号：TN929.5[电子电信—通信与信息系统]