Fisher-Information-Matrix Based Analysis of Semiblind MIMO Frequency Selective Channel Estimation

by the unknown blind symbols. It is demonstrated that the FIM for this system can be expressed as the sum of the blind FIM J b and pilot FIM J p . We present a key result relating the rank of the FIM to the number of blindly identifiable parameters. We then present a novel maximum-likelihood (ML) scheme for the semiblind estimation of the MIMO FIR channel. We derive the CramerRao Bound (CRB) for the semiblind scheme. It is observed that the semi-blind MSE of estimation of the MIMO FIR channel is potentially much lower compared to an exclusively pilot-based scheme. Finally, we derive a lower bound for the minimum number of pilot symbols necessary for the estimation of an FIR MIMO channel for any general semi-blind scheme. Simulation results are presented to augment the above analysis.