EM algorithm with sphere decoding for joint channel estimation and detection in MIMO systems

In this paper, we introduce a novel method for joint channel estimation and symbol detection in a MIMO wireless communication system. The algorithm uses the expectation-maximization (EM) algorithm for channel estimation, together with a new complex-domain sphere decoding (SD) algorithm for near-optimal detection of data symbols. The proposed algorithm is tested on a MIMO communication system. Simulation results show that, even with a short training sequence, the algorithm provides a near optimal performance with a reasonable computational complexity. We also compare the computational complexity of the proposed sphere decoding approach with other techniques and show that it has a lower computational complexity without any performance penalty.