Blind Channel Estimation for MIMO Uplink Single Carrier CDMA Block Transmission Systems

In this paper, we propose the application of two blind channel estimation algorithms namely the subspace approach and the autocorrelation contribution method (ACM) algorithm for multiple input multiple output (MIMO) single-carrier CDMA (SC-CDMA) block transmission systems in the quasi- synchronous uplink scenario. Using only second order statistics, the ACM approach shows similar performance to that of subspace based approach with the added advantage of eliminating the need for rank estimation and noise power calculation as in subspace technique. The guard band utilised serves the dual role of eliminating ISI (inter-signal interference) and aiding the blind channel estimation stage. The use of cyclic prefix (CP) as well as zero padded (ZP) guard band for blind channel estimation is explained with simulation results highlighting the robust nature of ZP based schemes to blind channel estimation as compared to CP based system.