A MULTI-CARRIER CDMA MOBILE COMMUNICATIONS SYSTEM EMPLOYING PRE-RAKE AND DIVERSITY

Abstract

In this thesis a combination of orthogonal frequency division multiplexing (OFDM) and code division multiple access (CDMA) has been proposed for application in a mobile personal communications system. This is called Multj- uamer (MC) CDMA system, Tt combines a high ^ctral efficiency with an immunity to channel dispersion. Furthermore instead ol building a rake receiver in the mobile LUUI (MLf), the hose station (BSJ can prs-rake the signal before transmission in the downlink using the channel impulse response estimated liom the uplink. The mobile unit uses a conventional receiver and still achieves approximately the same performance as in the case of the rake receiver. For farther improvement % dual transmitter diversity is employed to combat fading. Theoretical and iimulation results are obtained fbr the system under consideration. Depicted results show appreciable improvements when compared with those previously considered in the literature.