A cluster-based relay selection method aided to avoid relay collision in multi-user VANETs

Vehicular ad hoc networks (VANETs) differ from traditional cooperative networks and wireless sensor networks due to their high speed, mobility constraints and information's variety they gathered. In order to solve above relay collision problem in VANETs, we propose a cluster-based relay selection method in high speed multi-user VANETs in this paper. Firstly, the sources can be classified in terms of the information they gathered. For example, the source gathers traffic accident information will have the higher grade than the one gathers road conditions. Then, the source with higher grade can select relay preferentially. Secondly, we proposed a cluster-based relay selection method in terms of the source-relay channel power |h
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. The relay in one cluster would only help its cluster head to forward the source information, which can avoid relay collision efficiently. Finally, the cluster head selects one “best” relay with the highest relay-destination channel power |h
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. The simulation results show that the cluster-based relay selection method not only avoids relay collision, but also outperforms the random relay selection ones even in high speed scenario.