The MAC Layer of VANETs

The design of the Medium Access Control (MAC) layer for vehicular networks should carefully cope with fast changing topologies caused by vehicle mobility, short connection lifetimes, harsh propagation environments, high node density, and heterogeneous traffic nature and quality demands. This chapter provides a detailed description of MAC functions (i.e., channel access rules, prioritization schemes, frame types, and formats), as specified by the IEEE 802.11p and ETSI ITS-G5 standards, and the multichannel operation. By discussing the main challenges which the MAC has to deal with, the chapter also presents the main evaluation tools (analytics, simulations, field-tests) that can be used to analyze the MAC performance.