一种改善的MIMO-OFDM系统MAP信道估计

An Improved MAP Channel Estimation for MIMO-OFDM Systems

在MIMO-OFDM系统下提出一种最大后验概率(MAP)信道估计算法.该算法利用期望最大化(EM)算法把MIMO信道估计分解为一系列独立的SISO信道问题,降低了MAP算法的计算复杂度.同时,根据在角域内不同发送和接收天线间的信道可近似为空间不相关,利用最有用抽头(MST)技术来减小噪声对估计性能的影响.仿真实验表明,与传统LS和EM算法相比,所提算法在低信噪比下具有较低的估计误差.

A maximum a posteriori probability （MAP） algorithm was proposed for the multiple-input multiple-output with orthogonal frequency division multiplexing （MIMO-OFDM） systems,which reduces the computation complexity via the expectation maximum （EM） algorithm to decompose the MIMO channel estimation into a series of independent single-input/single-output（SISO） channel estimation. Besides,according to that the MIMO channels between sending and receiving antennae in an angle domain approximate to spatial independence,the most significant taps （MST） technique was employed to reduce the effect of noise on estimated performance. Simulation results indicated that the proposed algorithm gets lower estimation error at low SNR than conventional LS and EM algorithms.