Multipath interference canceller for high-speed packet transmissionwith adaptive modulation and coding scheme in W-CDMA forward link

摘要

This paper proposes a multipath interference canceller (MPIC)nassociated with orthogonal code-multiplexing that achieves much highernpeak throughput than 2 Mbit/s with adaptive data modulation fornhigh-speed packet transmission in the wideband direct sequence-codendivision multiple access (W-CDMA) forward link, and evaluates itsnthroughput performance by computer simulation. The simulation resultsnelucidate that sufficient multipath interference (MPI) suppression isnachieved by a four-stage MPIC with 6-12 orthogonal code-multiplexingnusing one iterative channel estimation with pilot and decision feedbackndata symbols and further that the interference rejection weight controlnaccording to the number of observed multipaths is effective in improvingnthe throughput. It is also demonstrated that MPIC exhibits a superiornMPI suppression effect to a chip equalizer in the lower received signalnenergy per bit-to-background noise spectrum densityn(Eb/N0) channel around 0-3 dB owing to thensuccessive channel estimation at each stage. We show that the maximumnpeak throughput using MPIC is approximately 2.1 fold that without MPICnin a two-path and three-path Rayleigh fading channel and that the peaknthroughput of 8.0 Mbit/s is achieved using 64 QAM data modulation in antwo-path fading channel within a 5 MHz bandwidth. Furthermore, thenrequired average Eb/N0 for satisfying the samenthroughput with MPIC is decreased by more than 2.0 dB