Channel tracking techniques for OFDM systems in wireless access vehicular environments

Current OFDM based wireless LAN systems assume relative static channel response over the entire packet burst length. This paper proposes applying adaptive filtering concepts to channel estimation of current standardized OFDM systems in order to track the rapidly fluctuating channel response of wireless access vehicular environments (WAVE) for 5.9 GHz dedicated short range communications (DSRC). Different possible reference signals are considered for channel tracking, namely, pilots, symbol demapping output, and Viterbi decoder output. Pilot-aided channel tracking is not feasible with the standard current pilot structure since the number of available pilot subcarriers does not suffice in making an accurate channel estimate. Based on simulations, Viterbi-aided channel estimation has a slight advantage over channel estimation aided by the demapping circuit. Overall, applying channel tracking improves the performance of DSRC systems.