Adaptive Duplicated Filters and Interference Canceller for DS-CDMA Systems

A low complexity multiuser detection (MUD) technique, the Adaptive Duplicated Filters and Interference Canceller (ADIC) (patent pending), is proposed in the DS-CDMA context. Of particular interest is the use of adaptive filters block (AFB) dedicated to each user with its respective input signals independent from other users' contributions. The AFBs are mixed with interference canceller block in a cascade arrangement. As shown in this paper, this MUD can outperform the Decision Feedback Soft MultiStage Interference Canceller (DF-Soft-MPIC) MUD with complexity reduction by a factor of 4 to 8 for the data payload throughput from 64 kbps to 384 kbps, respectively. In addition to performance and algorithmic description of the proposed MUD method, a VLSI implementation strategy and hardware resources evaluation are investigated; permitting to estimate the maximum number of users in FPGA devices with respect to WCDMA constraints. The present work proposes a low complexity MUD wherein an interesting trade-off between performance and implementation complexity is described.