MMSE Multi-User Detection with GA-assisted Channel Estimation for STBC MC-CDMA Mobile Communication Systems

In the recent years, MIMO MC-CDMA techniques have been proposed in order to increase system capacity over frequency-selective wireless channels. The key feature of MIMO MC-CDMA is the capability of exploiting diversity jointly in time, frequency and space domains. In particular, Alamouti's coding scheme has been proposed as a very simple and mathematically elegant tool in order to implement space-time block coding. The main problem to be addressed is to effectively recombine diversity in order to achieve the best performances in the presence of multi-user interference. In this paper, we are proposing a low-complexity linear multi-user receiver based on the MMSE criterion supported by a Genetic-Algorithm (GA)-assisted MMSE channel estimation. Numerical results show performances very close to MMSE MUD exploiting ideal knowledge of channel state information, thus confirming the near-optimal behavior of genetic algorithms in signal detection and equalization.