Timing estimation in multiple-antenna systems over Rayleigh flat-fading channels

In this paper, we investigate the problem of timing estimation in multiple-antenna systems with the aid of training signals. A slow, independent and identically distributed (i.i.d.) Rayleigh flat-fading channel model is considered. We derive two maximum likelihood (ML) timing estimators based on two different approaches, namely treating the channel deterministic and random, respectively, and present the corresponding Cramer-Rao bounds (CRBs). Then the optimal designs of training signals based on some figures of merit associated with the CRBs are discussed.