Joint Fine Time Synchronization and Channel Estimation for MIMO-OFDM WLAN

Abstract

The fine time syncllronization for OFDM (ortllogonal frequency division multiplexing) system is carried out by taking cor·relation between the received sequence and reference sequence. This conventional method sllows unsatisfactory performllnce in WLAN (wireless local area network) environment due to large value of rms delay spread. This paper proposes an algorithm to improve the performance of the estimator by exploiting the characteristics of the channel. We also present a channel estimation algoritltm in time domain for MIMO-OFDM (multiple-input multiple-output OFDM) with tile same complexity as that in single antenna sy stem. The simulation results show that (1) For symbol time synchronization, the probability of incorrect timing in proposed aIgorithm is hundreds times lower than that in conventional algorithm. (2) For channel estimation, witb the use of two consecutive training sequences as in standard IEEE 802.11a, there is JdB decrease in SNR to acbieve the same MSE as in case of one training sequence only.