放大转发异步协作通信系统中的差分空时频传输方案  

Differential Space-Time-Frequency Transmission for Amplify-and-Forward Asynchronous Cooperative Communications

作　　者：高贞贞[1] 朱世华[1] 徐静[1] 

机构地区：[1]西安交通大学电子与信息工程学院,西安710049

出　　处：《西安交通大学学报》2009年第6期62-66,112,共6页Journal of Xi'an Jiaotong University

基　　金：国家自然科学基金资助项目(60372055);教育部高等学校博士学科点专项科研基金资助项目(20030698027)

摘　　要：针对频率选择性信道下的异步协作分集系统中信道估计复杂度高及中继传输异步问题,提出了一种采用放大转发协议的异步差分空时频编码传输方案(ADSTF).该方案首先在源节点对数据符号进行满分集旋转、Cayley变换及正交频分复用(OFDM)调制,然后在中继节点将接收符号放大转发,构造了一种分布式差分空时频编码.在目的节点未知信道状态信息、中继节点非完全同步的情况下,ADSTF方案能够同时获得空间分集和多径分集.与采用差分正交空时分组码的OFDM传输方案相比,ADSTF方案能够获得更高的分集.仿真结果表明,与采用BPSK调制的DOSTBC-OFDM方案相比,ADSTF方案仅以0.25 b/(s.Hz)的速率损失为代价,就能在误比特率为10-3时获得3 dB的信噪比增益.Focusing on asynchronous cooperative communication systems over frequency-selective fading channels, a distributed differential space-time-frequency （ADSTF） coding scheme is proposed by using the amplify-and-forward protocol. By applying full diversity rotation, Cayley transformation and OFDM modulation at the source node and then amplifying and forwarding the received signal at the relays, a ADSTF code is constructed. The proposed scheme can achieve both spatial and multi-path diversities without either perfect synchronization at the relays or any instantaneous channel state information at the destination node. Compared with the differential OSTBC OFDM transmission, the ADSTF transmission scheme can obtain higher transmit diversity. Simulation results show that the ADSTF scheme outperforms the differential OSTBC- OFDM scheme with BPSK modulation by 3 dB at bit-error-rate of 10 3 with only a rate loss of 0.25 b/（s. Hz）.

关 键 词：差分空时频编码 Cayley变换 多径分集 

分 类 号：TN929.5[电子电信—通信与信息系统]