An intervehicle communication protocol using dynamic PN-assignment DPA

This article proposes a control system for a vehicular network connecting a utomobiles with intervehicle communication. The authors used spread spectru m communication and devised a network formation where each vehicle composes the link independently, integrating the communication to the surrounding v ehicles and the intervehicular distance measurement. Code division multiple access (CDMA) communication is primarily used, and the multiplexing is rea lized by assigning the PN code sequence (code) to the vehicles. In this sys tem, the communication from the vehicle can be passed to the counterpart by knowing the PN code sequence of the counterpart. However, when a finite nu mber of codes are assigned and fixed to vehicles moving at random, the comm unication may be subject to interference by the approach of vehicles with t he same code. This article aims at the efficient use of finite PN code sequ ences by the vehicles and proposes a communication system where the PN code sequence can be modified when vehicles with the same PN code sequence appr oach each other. The performance is evaluated by simulation. Problems and f uture improvements are discussed. (C) 2000 Scripta Technica.