Receptores Iterativos para Canais MIMO Seletivos em Freqüência e Quase Estáticos: Uma Análise Comparativa

Abstract

We introduce two different iterative receivers for space-time coded data transmitted through frequency selective fading channels. Both receivers operate semi-blindly and make use of the expectation maximization algorithm for estimating the unknown channel. The approaches differ in the sense that maximum-a-posteriori data detection and decoding are either performed over a supertrellis or over separate trellises. The two approaches are compared in terms of trellis complexity, achievable diversity level. and bit error rate. The supertrellis approach shows to be less computational demanding and has a faster convergence rate. The separate approach can achieve a higher diversity level and thus a smaller bit error rate. We explore this trade-off with examples and computer simulations. These show that, in many cases, the supertrellis approach can be a better solution than the separate approach.