Markov chain Monte Carlo techniques in iterative detectors: a novel approach based on Monte Carlo integration

We present a novel soft-in soft-out (SISO) detection scheme based on Markov-chain Monte-Carlo (MCMC) simulations. The proposed detector is applicable to both synchronous multiuser and multiple-input multiple-output (MIMO) communication systems. Unlike previous publications on the subject, we use Monte Carlo integration technique to arrive at the receiver structure. The proposed multiuser/MIMO detector is found to follow the Rao-Blackwell formulation and found to result in much more reliable systems than those reported so far in the literature. In particular, through computer simulations, we demonstrate that the proposed receiver can easily handle the cases of overloaded systems, i.e. when in a multiuser set-up the number of users is larger than the spreading gain, or when in a MIMO set-up there are more transmit antennas than receive antennas.