一种降低接收机复杂度的差分空时调制方案
A Differential Space-Time Modulation Scheme with Reduced Receiver Complexity
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摘要: 基于对角信号的差分酉空时调制技术不需要信道估计并能实现满天线分集,但接收机的计算复杂度与发射天线数和数据率成指数关系。该文针对发射天线数为偶数的系统,提出了一种降低接收机计算复杂度的差分空时调制方案。该方案将发射天线分成相等数目的两组并在每一组天线上分别进行对角酉空时调制,接着构造差分编码矩阵使得两个对角信号的最大似然检测可以分开进行,从而大大降低了接收机的计算复杂度。理论分析和仿真表明,该方案仍实现了满天线分集,并且对于某些应用环境能提供比对角信号更好的误比特率性能。Abstract: Differential Unitary Space-Time Modulation (DUSTM) based on diagonal signals achieves full antenna diversity without requiring channel estimation. However, its receiver has a computational complexity that grows exponentially with the number of transmit antennas and the data rate. To reduce receiver complexity, a new DUSTM scheme is proposed for systems where the number of transmit antennas is even. The scheme partitions transmit antennas into two groups with equal number of antennas, and diagonal unitary space-time modulation is applied on each group. The differential encoding matrix is constructed so that maximum-likelihood detection of the two diagonal signals can be decoupled, thereby reducing receiver complexity significantly. Theoretical analysis and simulation results show that the proposed scheme preserves full antenna diversity and provides better bit-error rate performance than diagonal signals in some scenarios.
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