Training Design for Multipath Channel and Frequency-Offset Estimation in MIMO Systems

This paper addresses the problem of training design for frequency-selective channel and carrier frequency-offset (CFO) estimation in single- and multiple-antenna systems under different energy-distribution constraints. The performance metric used here is the Cramer-Rao bound (CRB). The paper first addresses the CFO-free case and then generalizes the results to include CFO-corrupted scenarios. Training sequences are designed that render the CRB for the CFO independent of the channel zeros. The proposed training designs also facilitate simple implementation of the maximum-likelihood CFO and channel estimators. Simulation results illustrate the merits of the proposed training designs