Space-time pre-equaliser for the downlink channel of UMTS-TDD

This communication deals with space-time pre-equalisation for UMTS-TDD systems. The motivation for that lies in the fact that the up and downlink channels are highly correlated, and thus the equalisation functions can be moved to the BS, therefore simplifying the receiver design. A design technique that explores the frequency redundancy of DS-SS signals is derived for a zero-forcing (ZF) multiple access interference (MAI) criterion. Preliminary examples show that significant improvements can be obtained in MAI dominating scenarios.