| Summary: | 碩士 === 元智大學 === 通訊工程學系 === 94 === Dedicated Short-Range Communication is an important part of the ITS. However, vehicle-use communication environments can cause the effect of Doppler shift and the time-varying channel, which lead a challenge to the receiver. In this thesis, an expatiation about the shape of Doppler spectrum and the method simulating time-varying channels is available.
We present a receiver structure suitable for DSRC, whose core is composed by a synchronizer, a one-tap frequency domain equalizer and Viterbi decoder, the equalizer uses normalized least-mean-square (NLMS) algorithm to track not only the variation of the DSRC channel but also the residual frequency and phase errors that not yet being entirely corrected by the synchronizer device. For getting more improvement, a code decision directed demodulation (CD3) scheme assisted by the decoder output could be adopted to help track.
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