VeMAC: A TDMA-Based MAC Protocol for Reliable Broadcast in VANETs

TLDR

The need for an efficient broadcast MAC protocol is critical for high‑priority safety applications in vehicular ad hoc networks (VANETs). This paper introduces VeMAC, a novel multichannel TDMA MAC protocol designed for VANET scenarios. VeMAC enables efficient one‑hop and multihop broadcast on the control channel by using implicit acknowledgments, eliminating hidden terminals, assigning disjoint time‑slot sets to vehicles moving in opposite directions and to roadside units, and is evaluated through analysis and simulation in highway and city scenarios against the existing ADHOC MAC. VeMAC achieves significantly higher control‑channel throughput than ADHOC MAC by reducing transmission collisions.

Abstract

The need of a medium access control (MAC) protocol for an efficient broadcast service is of great importance to support the high-priority safety applications in vehicular ad hoc networks (VANETs). This paper introduces VeMAC, a novel multichannel TDMA MAC protocol proposed specifically for a VANET scenario. The VeMAC supports efficient one-hop and multihop broadcast services on the control channel by using implicit acknowledgments and eliminating the hidden terminal problem. The protocol reduces transmission collisions due to node mobility on the control channel by assigning disjoint sets of time slots to vehicles moving in opposite directions and to road side units. Analysis and simulation results in highway and city scenarios are presented to evaluate the performance of VeMAC and compare it with ADHOC MAC, an existing TDMA MAC protocol for VANETs. It is shown that, due to its ability to decrease the rate of transmission collisions, the VeMAC protocol can provide significantly higher throughput on the control channel than ADHOC MAC.