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,传统系统中针对单个频偏的简单补偿方法不再适用.不同于已有的使用高复杂度矩阵求逆运算的线性频域均衡方法,本文利用迫零(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无需矩阵求逆运算的载波频偏补偿方法.仿真结果表明,在ITU-R M.1225信道模型的三种低时延扩展测试环境下,使用本文所提频偏补偿方法进行频偏补偿能有效改善系统误符号率(SER)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(CFO) between the receiver and each transmit antenna are possibly different,the simple CFO compensation method used in conventional systems becomes invalid.Rather than the existing linear frequency-domain equalization method that involves computationally complex matrix inversions,we proposed a CFO compensation method without need for matrix inversion by exploiting the underlying characteristics of the Zero-Forcing(ZF) detection and assuming low delay spread of the multipath channel.Simulation results show that the Symbol Error Rate(SER) performance of the system is significantly improved by using the proposed CFO compensation method in the low delay spread cases of the three test environments in the ITU-R M.1225 channel model.