分布式V-BLAST OFDM中存在多个频偏时的信号检测

Detection in Distributed V-BLAST OFDM with Multiple Frequency Offsets

在采用分布式发射天线的垂直贝尔实验室分层空时结构(V-BLAST)正交频分复用(OFDM)系统中,由于各发射天线与接收机之间的载波频偏(CFO)均可能不同,因此必须在信号检测中考虑多个频偏的影响。该文利用迫零(ZF)检测的固有特性,提出一种适用于低时延扩展多径信道的低复杂度频偏校正方法;再针对其不足,结合传统频偏校正方法,提出了采用两次频偏校正的基于迫零的信号检测方法。仿真结果表明,在低时延扩展信道下,该文所提频偏校正方法能有效消除多个频偏对系统性能的影响;且在时延扩展较大时,采用两次频偏校正的信号检测方法能进一步改善系统性能。

In vertical Bell labs layered space-time （V-BLAST） orthogonal frequency division multiplexing （OFDM） systems with distributed transmit antennas, since the carrier frequency offsets （CFOs） between the receiver and each transmit antenna are possibly different, the effects of multiple CFOs should be taken into account in detection. This paper first proposes a low-complexity CFO correction method for low delay spread channels by exploiting the underlying characteristics of zero-forcing （ZF） detection; and then proposes a ZF based detection method involving two CFO correction processes by combining the proposed CFO correction method with the conventional one. Simulation results show that the proposed CFO correction method can effectively eliminate the effects of multiple CFOs in low delay spread channels; while in channels with larger delay spread the proposed detection method involving two CFO correction processes can further improve the system performance.