Multipath Interference Canceller for Orthogonal Code-Multiplexed Channels and Its Performance in W-CDMA Forward Link

Akhmad Unggul PRIANTORO  Heiichi YAMAMOTO  Kenichi HIGUCHI  Mamoru SAWAHASHI  

Publication
IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E85-A   No.7   pp.1524-1535
Publication Date: 2002/07/01
Online ISSN: 
DOI: 
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section on Multi-dimensional Mobile Information Networks)
Category: 
Keyword: 
W-CDMA,  forward link,  orthogonal variable spreading factor,  multipath interference canceller,  

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Summary: 
This paper proposes a multipath interference canceller (MPIC) for orthogonal code multiplexed channels in the W-CDMA forward link and evaluates by computer simulation the improvement in BER performance owing to the multipath interference (MPI) suppression effect obtained by the MPIC. The simulation results show that a one-stage MPIC, which removes the MPI from the common pilot channel (PICH), common control channel (CCH), and synchronization channel (SCH), achieves a sufficient MPI suppression effect, and that the required received Eb/N0 of the traffic channel (TCH) at the average BER of 10-3 using the MPIC for the common channels is decreased by approximately 6.5 dB compared to that with a matched filter (MF)-based Rake receiver (the transmit power ratio of each common channel to TCH: ΔPICH/TCH=0 dB, ΔCCH/TCH=5 dB, ΔSCH/TCH=3 dB, without fast transmit power control (TPC) and antenna diversity reception). We also show that by using MPIC, the required transmit Eb/N0 at the average BER of 10-3, when the ratio of the target Eb/I0 of the 9-interfering users to desired user is ΔInt/Des=6 dB with fast TPC, is increased by only approximately 0.6 dB compared to that when ΔInt/Des=0 dB. This implies that the preferential MPI suppression from high-rate TCHs that abates the increase in complexity in a mobile terminal is effective in increasing the link capacity in the forward link.