Cooperative clustering-based medium access control for broadcasting in vehicular ad-hoc networks

Owing to the advancement of wireless communication technologies, the vehicular ad-hoc network (VANET) has experienced a rapid development in recent years. However, it is challenging to design a reliable and efficient medium access control (MAC) protocol for safety messages with strict quality of service demands, owing to unreliable wireless links and frequent changes of topology. On the other hand, cooperative communication can enhance the reliability of wireless links by exploiting the spatial diversity. The authors present here a cooperative clustering-based MAC (CCB-MAC) protocol for VANETs, in order to improve the transmission reliability of safety messages. In CCB-MAC, the selected helpers relay the safety message to the nodes that have failed in reception during the broadcast period. In addition, cooperation is conducted in idle slots, without interrupting the normal transmission. Both mathematical analysis and numerical results demonstrate that CCB-MAC increases the successful reception rate of safety messages significantly.