Pilot based channel estimation for frequency selective multi-user MIMO MC-CDMA systems

Multiple-input multiple-output (MIMO) multi-carrier code division multiple access (MC-CDMA) wireless systems are sensitive to multi-user interference (MUI), which increases with increase in the number of users. In order to study its effect, pilot based linear channel estimators are derived considering also the effect of MUI in frequency-selective MIMO MC-CDMA wireless systems. The proposed schemes are based on the novel multi-path multi-carrier decorrelator (MMD) receiver structure and include the maximum likelihood (ML), Wiener filter (WF) and matched filter (MF) techniques. Further, we derive closed form expressions for the biases and variances of the various estimators. Simulation results demonstrate the MSE performance of the proposed estimators. Further, the derived analytical expressions can also be seen to accurately predict the simulation results.