A differential OFDM approach to coherence time mitigation in DSRC

Abstract

As a modification to IEEE 802.11a, the current DSRC standard copes adequately with many of the impairments found in the vehicular wireless channel. However, measurements have shown that these mobile channels exhibit substantially shorter coherence times than those encountered in the indoor environments expected by 802.11a. We propose a modification to the coherent OFDM structure of DSRC, known as time-domain differential OFDM, that preserves the benefits of OFDM while adding robustness to short coherence times. Simulations verify the efficacy of this method over various Doppler spreads and packet lengths.