Pilot symbol initiated optimal decoder for the land mobile fading channel

We investigate the use of the expectation-maximization (EM) algorithm for estimating sequences of two-dimensional constellation signals transmitted over Gaussian fading channels with diversity reception. The algorithm performs coherent decoding with the use of pilot symbols. It is shown that the performance of the algorithm approaches that of the optimal maximum-likelihood (ML) receiver with linearly increasing complexity as a function of the sequence length. The uncoded performance as well as the coded performance are simulated, and compared with that of other algorithms.