A Survey of Coding and Modulation Techniques for Inter-Vehicular Communications

Direct inter-vehicular communication means that there is no infrastructure. This is in sharp contrast to mobile communication within a cellular network or between a moving vehicle and the roadside. It is assumed in this article that the mobile channel between the two vehicles is too rapidly time variable to be possible to measure it in real-time. The natural choice is then to select those coding and modulation techniques for which the knowledge of the channel state is not necessary at both the transmitter and the receiver, that is, to consider only differential and noncoherent communications technologies. As interesting options, the celebrated Golden code and the recently developed Golden-Alamouti space-time trellis coding are also proposed for inter-vehicular communications.

Modulation and Coding Techniques for Inter-Vehicular Communications

Direct inter-vehicular communications are presumably more difficult to perform than communications within a cellular network or between a moving vehicle and the roadside, where there is a large fixed infrastructure. It is assumed in this chapter that the mobile channel between the two vehicles is so rapidly variable that it is not possible to measure it in real-time. The authors therefore selected and considered only modulation and coding techniques for which the knowledge of the channel state was not necessary at both the transmitter and the receiver, that is, differential and noncoherent communications. To be realistic, only space-time coding communication systems with two transmit antennas were considered. The authors have purposely avoided too much theoretical development, with the intent of making clear that the implementation of all the techniques mentioned in this chapter, it should not be a too difficult task for the electronic technology of today. Future research directions are also suggested to conclude the chapter.