eHER-MAC: An Enhanced HER-MAC for Vehicular Ad-hoc Networks

To enhance the saturation throughput in Vehicular Ad-hoc NETworks (VANETs), one of solutions is a variable Control CHannel Interval (CCHI) multichannel Medium Access Control (MAC) scheme. Recently, the HER-MAC is more reliable and efficient in both the safety message broadcast and the service channel utilization. HER-MAC which requires lower time for reservation period than IEEE 1609.4 improves the throughput of non-safety message. In this paper, we propose a new algorithm, named eHER-MAC, which reduces the length of reservation period. The eHER-MAC protocol supports more efficient in the safety message broadcast. The simulated result shows that eHER-MAC has lower average number of frames to re-sizing the reservation period and average number of time slots for reservation period than HER-MAC with the same nodes. Key word: MAC, Control Channel Interval, HER-MAC, reservation period.