Multipath interference canceller for high speed downlink packet access in enhanced UMTS networks

This paper addresses the problem of the UMTS downlink multipath interference and its impact on the performance of the high speed data packet access (HSDPA). The performance is studied for specific channel quality indicator (CQI) values defined in 3GPP, using both QPSK and 16-QAM modulations. It is shown that the multipath interference introduced by the channel induces a severe performance loss, which is especially relevant for the CQI with 16-QAM modulation, with a high number of concurrent physical channels. A multipath interference canceller (MPIC) using clipped soft decision (CSD) is proposed for suppressing this interference. Results with and without MPIC are presented, showing that a considerable performance gain can be obtained with the use of the MPIC.