On system capacity and coverage improvements by linear multiuser detection for UMTS

The main objective of this paper is to investigate linear multiuser detection in an UMTS network in terms of system capacity and system coverage. This includes the impact of linear multiuser detection on radio resource management concepts as load control and power control. One issue the paper deals with is joint optimization of linear multiuser detection with power control. In order to keep practical UMTS issues in mind, we describe an iterative two-stage power control multiuser detection algorithm for UMTS application. With this algorithm detailed system level simulation will be carried out to show coverage and system capacity gains. As an example, we work out the maximum allowable cell radius for a given cell load and outage probability. The main result indicates for UMTS that optimum minimum mean squared error (MMSE) multiuser detection yields moderate gains compared to single-user-matched filtering. The linear decorrelator is even inferior to the single-user-matched filter.