System capacity enhancement by using multi-user processing techniques in narrowband satellite mobile communications

The system capacity is tied to robustness versus co-channel interference (CCI). Three receivers (a conventional single-user coherent receiver, an approximated maximum likelihood receiver with multi-user detection, and a "decorrelating receiver") for a diversity coded system are compared and their performance versus CCI is reported. Multi-user and decorrelation detection provide a means to approach CDMA performance by TDMA. A fundamental limitation of conventional receivers is that their decision metric does not take into account the statistics of the interfering signals, which are treated like noise. We show how some concepts developed in the context of multi-user communications were put to work in the design of receivers for coded transmission over narrowband fading channels with diversity. Our analysis focuses on the Rayleigh channel, but we also provide simulation results for the land mobile satellite channel.