An Analytical Model of CSMA/CA Performance For Periodic Broadcast Scheme

摘要

In highly-mobile environments such as Vehicle Ad Hoc Networks (VANETs) or Flying Ad Hoc Networks (FANETs), the status messages that contain information on speed, position, and direction should be transmitted periodically by each vehicle in the network to its neighbors to support situation-based traffic applications. Many analytical models have been proposed to evaluate the MAC layer performance of status message transmission based on the Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) protocol. However, they either fail to consider lifetime of status messages or assume a random arrival of status messages. In addition, all these models are based on the assumption that distribution of MAC layer states is unchanged with the time, which is not applicable in the periodic broadcast schemes. In this paper, we propose an analytical model where constant arrival intervals and lifetime expiration of messages are simultaneously considered. Moreover, we discard the assumption of unchanged states distribution by introducing a pure death process. The proposed model is verified with simulation data obtained by NS2, and results showed that proposed model can accurately capture the reception probability, collision probability, and discard probability of periodic broadcast messages.