H-inf channel estimation for MIMO-OFDM systems in the presence of carrier frequency offset

An H-infinity (H-inf) channel estimation algorithm is proposed for estimating the channels in MIMO-OFDM systems in the presence of carrier frequency offset (CFO). The goal is to contribute to an algorithm with low complexity, good estimate performance and better suppression to CFO. For this purpose, the H-inf with simplified objective function is first developed, and then, its computational load is reduced by using the iterative expectation maximization (EM) process. To resistant the CFO, we derive a precise equivalent signal model (ESM) to identify the channels. It is observed that the H-inf estimator could be regarded as a substitute for optimal maximum a posteriori (MAP) estimator, but with much less complexity. At the same time, by using ESM, a remarkable improvement for the performance degradation caused by CFO will appear.