Abstract
Many Carrier Sense Multiple Access (CSMA) and Time Division Multiple Access (TDMA) based medium access control (MAC) protocols for vehicular ad hoc networks (VANETs) have been proposed recently. Contrary to the common perception that they are competitors, we argue that the underlying strategies used in these MAC protocols are complementary. Based on this insight, we design CTMAC, a MAC protocol that synthesizes existing strategies; namely, random accessing channel (used in CSMA-style protocols) and arbitral reserving channel (used in TDMA-based protocols). CTMAC swiftly changes its strategy according to the vehicle density, and its performance is better than the state-of-the-art protocols. We evaluate CTMAC using at-scale simulations. Our results show that CTMAC reduces the channel completion time and increases the network goodput by 45% for a wide range of application workloads and network settings.
Highlights
IntroductionVehicular ad hoc networks (VANETs) have attracted significant interest from both academia and industry
During the last decade, vehicular ad hoc networks (VANETs) have attracted significant interest from both academia and industry
Existing protocols only use one of the Carrier Sense Multiple Access (CSMA) and Time Division Multiple Access (TDMA) strategies and try to make it work under all scenarios. We argue that both CSMA and TDMA strategies should be used together, as they nicely complement each other
Summary
Vehicular ad hoc networks (VANETs) have attracted significant interest from both academia and industry. Due to the high mobility of vehicles, it is challenging to design an efficient medium access control (MAC) protocol with low delay and high reliability. Existing proposals have developed CSMA (Carrier Sense Multiple Access)- and TDMA (Time Division Multiple Access)-based MAC protocols to tackle this problem [8] All of these protocols have their own strengths and weaknesses: CSMA-based MAC protocols perform well for low vehicle density, but bring about high collision in the presence of vehicle crowding due to the random backoff method, while TDMA-based MAC protocols provide deterministic delay bounds by resource reservations, but are sensitive to underlying mobility and topology changes. To demonstrate the benefits of using these strategies together, we design CTMAC—a MAC protocol that synthesizes the random accessing channel (used in CSMA-style protocols) and the arbitral reserving channel (used in TDMA-based protocols).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
