A Novel MIMO SC-DS-CDMA HARQ scheme for Frequency Selective and Time Varying Channels

Abstract

We propose a multiple input multiple output single carrier direct-sequence code division multiple access (MIMO SC-DS-CDMA) transmission scheme of high speed broadband communication over time varying frequency selective Rayleigh fading channels. The system is used in conjunction with Hybrid Automatic Repeat reQuest (HARQ) to provide better BER performance and throughput. Furthermore, the proposed scheme employs both Time domain and Frequency domain spreading in contrast to other CDMA system which employs only Time domain spreading. The frequency domain spreading provides frequency diversity that improves the performance of the system. BER performance of the scheme is studied and the results are presented. Index Terms-code division multiple access (CDMA), multiple input multiple output ( MIMO), single carrier transmission (SC) , space-time spreading (STS), space-time-block coding (STBC), frequency domain spreading, frequency selective channels.