Blind Iterative Receiver for Multiuser Space-time Coding Systems

We consider a space time coding system. We propose to detect symbols of the each user and estimate the channel iteratively. The channel gets estimated blindly via Expectation Maximization (EM) algorithm by formulating the problem as Gaussian mixture model (GMM). The estimated channel is then used to detect the symbols for each user, which is also done in an iterative fashion, i.e., user-wise detection. We consider using finite alphabet for MAI, to simplify and to reduce the complexity of the resulting EM algorithm, we consider the introduction of Mean field methods for the approximation of the posterior MAI symbol probabilities. Simulations shows very useful behaviour of the proposed receiver.