Adaptive interleaver based on the measurement of Doppler shift in fading channel [vehicle speed measurement]

An adaptive interleaver based on the measurement of Doppler shift in fading channel is presented in this paper. It is known that the combination of channel coding with interleaver can effectively correct burst errors in fading channel. An interleaver can make channel actions on symbols in one decoder block appear to be independent. In general words, the deeper the interleaver is, the better the effect is, but the longer the delay is. The depth of interleaver is much related with the fading rate, i.e., it is dependent on the correlative time of fading channel. This paper gives out an adaptive interleaver by measuring vehicular speed, i.e. Doppler shift. From measurement of the Doppler shift by calculating variation of different of estimated fading factor, one can compute optimal interleaver depth, and then select appropriate interleaver both in the transmitter and receiver. By using this method, the average delay of interleaver can be decreased effectively. This paper presents this method and computer simulation results.