Efficient multiple access interference cancellation and users signal separation could be achieved by space-time equalization. However, receiver complexity like MLSE increases greatly with the number of transmit and receive antennas and channel memory. The problem of designing an equalizer to shorten the channel impulse response and reduce the complexity of MLSE equalization for a MIMO system is addressed in this paper. Impulse response shortening (IRS) equalizer is generalized for a MIMO system in two different methods: Decomposed-MIMO-IRS and MIMO-IRS. Finally, a channel impulse response matrix shortening (CIRMS) algorithm is introduced which decreases the effective channel’s memory, which is the multiplication of the number of transmit antennas and channel’s memory, instead of just decreasing the channel’s memory.

Keywords