Parallel-Type Coherent Multi-Stage Interference Canceller with Iterative Channel Estimation Using Both Pilot and Decision-Feedback Data Symbols for W-CDMA Mobile Radio

Koichi OKAWA  Kenichi HIGUCHI  Mamoru SAWAHASHI  

IEICE TRANSACTIONS on Communications   Vol.E84-B   No.3   pp.446-456
Publication Date: 2001/03/01
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Innovative Mobile Communication Technologies at the Dawn of the 21st Century)
mobile radio,  W-CDMA,  parallel-type coherent multistage interference canceller,  iterative channel estimation,  decision-feedback data symbol,  

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In order to increase the link capacity in the wideband direct sequence code division multiple access (W-CDMA) reverse link, employing a parallel-type coherent multi-stage interference canceller (COMSIC) is more practical than employing a serial (successive)-type due to its inherent advantage of a short processing delay, although its interference suppression effect is inferior to that of the serial-type. Therefore, this paper proposes a parallel-type COMSIC with iterative channel estimation (ICE) using both pilot and decision-feedback data symbols at each canceling stage in order to improve the interference suppression effect of the parallel-type COMSIC. Computer simulation results demonstrate that by applying the parallel-type COMSIC with ICE after FEC decoding, the capacity in an isolated cell can be increased by approximately 1.6 (2.5) times that of the conventional parallel-type COMSIC with channel estimation using only pilot symbols (the MF-based Rake receiver) at the required average transmit Eb/N0 of 15 dB, i.e. in the interference-limited channel. The results also show that, although the capacity in the isolated cell with the parallel-type COMSIC with ICE after FEC decoding is degraded by approximately 6% compared to that with the serial-type COMSIC with ICE after FEC decoding, the processing delay can be significantly decreased owing to the simultaneous parallel operation especially when the number of active users is large.