DOWNLINK DETECTION SCHEMES FOR MC-CDMA SYSTEMS IN INDOOR ENVIRONMENTS

Recently, considerable attention has been devoted to the combination o f direct sequence-code division multiple access (DS-CDMA) and multi-ca rrier (MC) modulation for high bit rate indoor wireless systems. In th is work we consider the downlink of a cellular MC DS-CDMA system. In p articular, we evaluate the performance of some detection schemes consi dering typical indoor radio channels. Channel estimation techniques ar e investigated and an effective sub-channel estimation technique is pr oposed. Moreover, we compare the performance of two equalization techn iques combined with two space diversity combining schemes. The results show that good performance can be obtained by a post-detection divers ity selection scheme combined with a MMSE equalization technique; more over, if a proper guard time is selected, performance is almost indepe ndent of the number of paths of the channel's impulse response. Result s are given in terms of BER obtained by means of analytical computatio ns and simulations.