Architectures for Symbol Timing Synchronization in MIMO Communications

ARCHITECTURES FOR SYMBOL TIMING SYNCHRONIZATION IN MIMO COMMUNICATIONS Kejing Liu Department of Electrical and Computer Engineering Master of Science Maximum likelihood symbol timing estimation for communication over a frequency non-selective MIMO fading channel is developed. The cases of known data (data-aided estimation) and unknown data (non-data-aided estimation) together with known channel and unknown channel are considered. The analysis shows that the log-likelihood functions and their approximations can be interpreted as SISO loglikelihood functions operating on each of the receive antennas. Previously published symbol timing estimators are shown to be special cases of the more general framework presented. Architectures based on both block processing and sequential processing using a discrete-time phase-locked loop are summarized. Performance examples over a MIMO channel based on measured data and on a simple stochastic MIMO channel model are given. These examples show that the mean-squared error performance of these techniques is not strongly dependent on the MIMO channel and is able to reach the Cramer-Rao bound when sufficient complexity is applied.