Cramer-Rao Lower Bound on Frequency Offset Estimation Error in OFDM Systems with Timing Error Feedback Compensation

Cyclic-prefix based carrier frequency offset (CFO) estimation techniques (frequency synchronization) are popular for OFDM systems. In the conventional CP-based maximum-likelihood (ML) algorithm, the accuracy of CFO estimation directly depends on the block timing estimation error. Recently, an enhanced frequency offset estimation technique based on ML algorithm was proposed, which incorporates timing error feedback compensation (TEFC). In this paper, we provide a detailed analysis of the Cramer-Rao lower-bound (CRLB) on the CFO estimation error when TEFC in incorporated. A closed form expression is derived for the achievable minimum mean-squared-error (MSE) of CFO. Simulation results show that the analytically derived CRLB is practically reachable for wide range of SNR