An Efficient Channel Tracking Method for OFDM Based High Mobility Wireless Multimedia System

Abstract

Preamble based channel estimation is widely used in OFDM based wireless multimedia system. However, the channel response varies significantly during one transmission packet due to high mobility. We propose new channel estimation method that, tracks the channel variation along the time. We take advantage of the pilots occupied for the phase tracking to catch the variation of the channel responses with slightly modified pilot structure. For the accurate channel tracking, the variation trend of the channel is examined by correlation analysis. In here, we see the linear channel variation and so we use the linear interpolation for channel tracking. Without loss of data rate, the method reduces the error floor of bit error rate (BER) dramatically. Simulation results demonstrate the capability of the proposed channel tracking scheme even though the Doppler shift is very large. Moreover, the proposed method shows more competitive performance in convolutional coded systems used in many wireless multimedia application like IEEE 802.11a.