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

Abstract EN

We present a study of semiblind (SB) estimation for a frequency-selective (FS) multiple-input multiple-output (MIMO) wireless channel using a novel Fisher-information matrix (FIM) based approach.

The frequency selective MIMO system is modeled as a matrix finite impulse response (FIR) channel, and the transmitted data symbols comprise of a sequence of pilot symbols followed by the unknown blind symbols.

It is demonstrated that the FIM for this system can be expressed as the sum of the blind FIM Jb and pilot FIM Jp.

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 Cramer-Rao 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.