A new multiple access scheme for DC power line communications

Contention detection and resolution procedure is presented. This procedure is tailored for use over the direct current (DC) power lines in automotive applications, but is also applicable for other multiple access networks. Each user randomly switching between carrier sense and carrier transmission modes prior to sending data accomplishes bus arbitration. If the bus is sensed busy during this process, then the user switches to a packet reception mode. Typically, contention detection and resolution are two separate procedures. The proposed scheme effectively combines the two while maintaining controlled probability of collision. Detailed analysis of this scheme is given, revealing that the collision probability can be made arbitrarily small for the price of slightly increasing packet over-head.