EM-based detection scheme for differential unitary space-time modulation  

基于EM算法的差分酉空时调制检测方案(英文)

作　　者：杜正锋[1] 陈杰[1] 潘文[1] 高西奇[1] 

机构地区：[1]东南大学移动通信国家重点实验室,南京210096

出　　处：《Journal of Southeast University(English Edition)》2007年第4期484-488,共5页东南大学学报（英文版）

基　　金：The National Natural Science Foundation of China(No60572072,60496311);the National High Technology Research and Development Program of China (863Program) (No2006AA01Z264);the National Basic Research Program of China (973Program) (No2007CB310603);the PhD Programs Foundation of Ministry of Educa-tion of China (No20060286016)

摘　　要：The performance loss of an approximately 3 dB signal-to-noise ratio is always paid with conventional differential detection compared to the related coherent detection. A new detection scheme consisting of two steps is proposed for the differential unitary space-time modulation （DUSTM） system. In the first step, the data sequence is estimated by conventional unitary space-time demodulation （DUSTD） and differentially encoded again to produce an initial estimate of the transmitted symbol stream. In the second step, the initial estimate of the symbol stream is utilized to initialize an expectation maximization （EM）-based iterative detector. In each iteration, the most recent detected symbol stream is employed to estimate the channel, which is then used to implement coherent sequence detection to refine the symbol stream. Simulation results show that the proposed detection scheme performs much better than the conventional DUSTD after several iterations.与相干检测相比传统差分检测会带来约3dB的性能损失.提出一种新的差分酉空时调制检测方案.该方案分为2步:首先将传统差分检测获得的数据序列进行差分再编码,作为对发送符号序列的初始估计;然后由期望最大化(EM)算法进行迭代检测,利用上一步得到的发送符号序列的初始估计值作为EM算法的初始值.在每一次迭代时,最新检测到的发送符号序列用来进行信道估计,随后利用估计出的信道实施相干序列检测,进一步提高对发送符号序列检测的准确性.仿真结果表明,经过几次迭代后,提出的检测方案性能大大优于传统的差分酉空时调制检测方案.

关 键 词：unitary space-time modulation differential detection expectation maximization （EM） algorithm 

分 类 号：TN911.23[电子电信—通信与信息系统]