Channel Tracking with Zero Padding Scheme for STBC-OFDM System under Fast Fading Environment

An inter-vehicle communication system is highly advantageous for driving safety support systems, such as collision avoidance systems at intersections. In an inter-vehicle communication system, a channel-tracking scheme is essential to achieve reliable wireless communication under the fast fading environment caused by surrounding vehicles. For coherent detection, decision feedback is a well-known channel-tracking scheme. In this scheme, replica signals are generated and channel estimation is performed by using the replica signals. However, because channel estimation performance depends on the signal-to-noise (SNR) at symbol time, decision feedback errors occur by the lower SNR caused by fast fading. The feedback errors degrade the transmission performance significantly. In an orthogonal frequency division multiplexing (OFDM) system, the time domain 0-padding scheme is a well-known channel estimation technique. Although better channel tracking performance is expected by applying the 0-padding scheme, the tracking performance is degraded when employing guard-bands in the OFDM system. In this paper, we propose an improved time domain 0-padding scheme for an STBC-OFDM system employing guard-bands based on the IEEE802.11p standard for inter-vehicle communication, and show the improved performance through computer simulations.