Multiple user maximum likelihood based sequence estimation for unknown, frequency selective, fast time varying channels

In this paper maximum likelihood sequence estimation (MLSE) is applied to unknown, frequency selective, fast time-varying channels. Assuming a first order Gauss-Markov probabilistic model for the FIR intersymbol interference (ISI) channels, a maximum a-posterior (MAP) or ML cost function for the communication symbols is obtained by integration over the channel FIR parameters. A reduced-complexity, time-recursive sequence estimation algorithm is then described which is based on per survivor precessing (PSP) and reduced state sequence estimation (RSSE).