Single-User Detectors for Multiuser Channels

摘要

Optimum decentralized demodulation for asynchronous Gaussian multiple-access channels is considered. It is assumed that the receiver is the destination of the information transmitted by only one active user, and single-user detectors that take into account the existence of the other active users in the channel are obtained. This approach is in contrast to both conventional demodulation, which is fully decentralized but neglects the presence of multiple-access interference, and globally optimum demodulation, which requires centralized sequence detection. The problem considered is one of signal detection in additive colored non-Gaussian noise, and attention is focused on one-shot structures where detection of each symbol is based only on the received process during its corresponding interval. Particular emphasis is placed on asymptotically optimum detectors for each of the following situations: 1) weak interferers, 2) CDMA signature waveforms with long spreading codes, and 3) low background Gaussian noise level.