一种新的低复杂度准正交酉空时调制

基于非相干U-空时调制，介绍了一种MIMO（多输入多输出）的低复杂度差分检测，接受端用最大似然准则判决时搜索空间大小只与传送速率成线性关系，且避免了星座扩展。并与OFDM（正交频分复用）结合实现了MIMO-OFDM的差分检测。虽然只能取得部分发射分集，但仿真结果表明，与全分集的差分检测相比，此差分检测在低信噪比时具有较低的误比特率。

A Novel Lower Complexity Quasi-orthogonal Unitary Space-Time Modulation

Based on the noncoherent unitary space-time modulation, a differential detector with lower complexity for MIMO（Multiple-input multiple-output） system is described. And ML（Maximum Likehood） search space size is linear to transmission rate at receiver, thus to avoid the constellation expansion. Then it is combined with OFDM （Orthogonal Frequency Division Multiplexing）, and differential detection for MIMO-OFDM is realized. The simulation results show that the proposed differential scheme has lower BER（Bit-Error-Rate） than differential detection with full-diversity at lower SNR（Signal-Noise-Ratio）, although only partial transmit diversity is obtained.