Adaptive beaconing schemes in VANETs: Hybrid approach

Beacon or safety messages are broadcasted by Vehicular Ad hoc Networks (VANETs) to disseminate network state or emergency incident information to other vehicles in the network. The freshness of information depends upon the frequent transmission of beacons. Similarly, to increase the awareness area or communicating with the distant nodes, beacons are transmitted with at high transmission power. However, increasing the beacon rate or transmission power has negative effects on information, communication efficiency because of the finite wireless link bandwidth. Therefore, different schemes have been proposed to individually control beacon´s transmission power, transmission rate, or contention window at the MAC layer, or combination of those, to achieve quality beacon communication in VANETs. The latter case is called hybrid adaptive beaconing schemes. In literature, there are many hybrid adaptive beaconing schemes that control multiple communication parameters to efficiently broadcast beacon messages in VANETs. In this paper, we briefly summarize various and qualitatively compare various aspects of those schemes. The open and challenging issues are also highlighted in this paper.