Improved Coarse Timing For Burst Mode OFDM

In this paper, a blind frame start estimation scheme is proposed to improve the coarse timing information obtained from a packet detector in burst mode OFDM systems. The proposed estimator is based on refining the location of an abrupt power change in a received signal. A maximum a posteriori (MAP) estimator of the frame start position is derived and its characteristics are presented. A sub-optimal reduced complexity, yet efficacious, implementation of the proposed estimator is also introduced. The estimator is evaluated in a simulated OFDM system and shown to reduce the variance of the coarse timing estimation error significantly.