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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.
Compared with the coherent detection, the traditional differential detection brings about about 3 dB loss of performance. A new scheme of differential unitary space-time modulation detection is proposed. The scheme is divided into two steps: Firstly, the data sequence obtained by traditional differential detection is differentially re-encoded , As an initial estimate of the transmitted symbol sequence, and then iteratively detected by the expectation maximization (EM) algorithm, using the initial estimate of the transmitted symbol sequence obtained in the previous step as the initial value of the EM algorithm. At each iteration, the latest detection The transmitted symbol sequence is used for channel estimation, and then the coherent sequence detection is performed by using the estimated channel to further improve the accuracy of the detection of the transmitted symbol sequence. The simulation results show that the performance of the proposed detection scheme is greatly improved after several iterations In the traditional differential unitary space-time modulation detection scheme.