ML-estimator and CRLB on carrier-frequency offset in TDM receivers for direction finding
Andreas Richter, Neelabh Kashyap · European Signal Processing Conference · 2011
Recently switched antenna array, sometimes also called Time Division Multiplexing (TDM), receivers have found their way in systems suitable for, e.g. indoor positioning. Such systems use low-power and low-cost transmitters and receivers, having significant differences in their local reference clocks. Consequently, the received signal in the base-band carries a carrier-frequency offset (CFO). This CFO has to be estimated from the observed signal and compensated for. In this paper Cramer-Rao lower bounds on the CFO for two data models of switched antenna array receivers signals are derived. Furthermore a closed form Maximum Likelihood Estimator (MLE) for the CFO and the antenna data is proposed. The derived CRLBs are used to study the statistical performance of the maximum likelihood estimator.