Frequency-Domain Pre-Equalization for MC-CDMA/TDD Uplink and Its Bit Error Rate Analysis

Satoshi ABE
Shinsuke TAKAOKA
Hiromichi TOMEBA
Fumiyuki ADACHI

IEICE TRANSACTIONS on Communications   Vol.E89-B    No.1    pp.162-173
Publication Date: 2006/01/01
Online ISSN: 1745-1345
DOI: 10.1093/ietcom/e89-b.1.162
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Wireless Communication Technologies
MC-CDMA,  frequency-domain pre-equalization,  frequency-selective channel,  

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In multi-carrier code division multiple access (MC-CDMA) uplink (mobile-to-base station), since different users' signals go through different frequency-selective fading channels, large multi-access interference (MAI) is produced. The use of frequency-domain equalization reception can only partially restore the orthogonality among different users' signals, resulting in a severe degradation in the bit error rate (BER) performance. Hence, frequency-domain pre-equalization transmission, which equalizes the MC-CDMA signal before transmission, is recently attracting attention. In this paper, we present a generalized minimum mean square error (GMMSE) frequency-domain pre-equalization transmission suitable for MC-CDMA/TDD uplink. The pre-equalization weight is derived based on the method of Lagrange multipliers. The theoretical analysis of BER performance using the GMMSE frequency-domain pre-equalization transmission in a frequency-selective Rayleigh fading channel is presented and the result is confirmed by computer simulation.