Multi User Detecion

Here I come to the main portion of my project...The evaluation for various detectors and finding the optimal one. First once more on MUD.
The use of multiple antennas at the transmitter and receiver results in Multiple Access Interference (MAI). Delay spread causes Inter-Symbol Interference (ISI). ISI can cause an irreducible error floor when the modulation symbol time is on the same order as the channel delay spread. Equalization defines any signal processing technique used at the receiver to alleviate the ISI problem caused by delay spread.Equalization techniques fall into two broad categories: linear and nonlinear. The linear techniques are generally the simplest to implement and to understand conceptually. However, they typically suffer from more noise enhancement than nonlinear equalizers, and are therefore not used in most wireless applications. We had considered Zero Forcing (ZF), Mean Square Error (MMSE) and Maximum a Posteriori (MAP) under linear equalizers and Nulling/Cancelaltion (N/C) and Maximum Likelihood (ML) under non-linear methods. Now to see them one by one.