Performance analysis of MIMO-MMSE-DFE multiuser receiver for TDMA mobile systems with spatial diversity

We consider the design and performance analysis of a multiuser detection (MUD) scheme which can increase the capacity of generic TDMA systems with spatial diversity. This scheme allows two users to occupy the same time slot for up-link transmission. At the base station, an MMSE multiple-input and multiple-output (MIMO) DFE receiver is designed to tackle various channel impairments such as Rayleigh fading, delay spread, and multiple access interference (MAI). Next, by using the Gaussian approximation (GA) technique and assuming a known MIMO channel, we derive the two user´s pseudo signal-to-noise ratios and then their theoretical error probabilities in a rather simple and insightful form. Furthermore, it is shown that without using any power control mechanism in the TDMA system, the near-far effect is not a curse but can be a blessing for the weaker user, provided that the two decision delay parameters are adjusted to their optimal values