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.
- Frequency-domain pre-equalization
- Frequency-selective channel
ASJC Scopus subject areas
- Computer Networks and Communications
- Electrical and Electronic Engineering