Joint symbol detection of multi-antenna signals based on EM

This paper presents a joint symbol detection algorithm based on expectation maximization (EM) for symbol detection of multi-antenna PSK and QAM signals with different phase offset. Adopting EM iterative, the algorithm realizes the maximum-likelihood (ML) estimation of PSK and QAM symbol detection over multi-antenna signals. A modified realization is proposed for practical signal stream processing and the convergence is proved too. Analysis and simulation results show that the algorithm depresses noise interference, improves signal quality and degrades symbol error ratio (SER) effectively by joint symbol detection of multi-antenna signals. Comparing with single channel, the phase estimation error degrades substantially and reaches modified Cramer-Rao bound (MCRB).