IEEE 802.11p performance evaluation and protocol enhancement

Abstract

The IEEE 802.11p Wireless Access in Vehicular Environment (WAVE) protocol providing for vehicle-toinfrastructure and vehicle-to-vehicle radio communication is currently under standardization. We provide an NS-2 simulation study of the proposed IEEE 802.11p MAC protocol focusing on vehicle-to-infrastructure communication. We show that the specified MAC parameters for this protocol can lead to undesired throughput performance because the backoff window sizes are not adaptive to dynamics in the numbers of vehicles attempting to communicate. We propose two solutions to this problem. One is a centralized approach where exact information about the number of concurrent transmitting vehicles is used to calculate the optimal window size, and the other is a distributed approach in which vehicles use local observations to adapt the window size. We show that these schemes can provide significant improvements over the standard MAC protocol under dense and dynamic conditions.

Mobility impact in IEEE 802.11p infrastructureless vehicular networks

“…As mentioned in Chapter 2, the original 802.11p protocol performance has been extensively studied and several drawbacks have been identified [5,17,18,7,6] The static parameters that are used in the 802.11p standard [4] do not take into account the number of communicating nodes [16], the speed of each node [3], the adaptivity of the backoff mechanism [7], and the fluctuation in vehicle density. All of these factors affect the efficiency and sharing of the communication medium.…”

“…In [7], simulation results of the IEEE 802.11p standard show that the fixation of the back-off window size does not guarantee the desired throughput in vehicular networks. Two algorithms for a dynamic back-off window size are proposed.…”

Rapid Prototyping for Evaluating Vehicular Communications

“…Due to the novelty of the IEEE 802.11p MAC layer, most of the evaluations of the standard in the literature are aimed at studying it by using simulators like ns-2 (75) or following analytical approaches (76). There are also software implementations of the standard: some of them describe generic transceivers (77), but the majority are focused on the performance of the receiver by using techniques for getting better channel estimations (78,79,80,81) or improved decisions (82).…”

Comparative Analysis of IEEE 802.11p and IEEE 802.16-2004 Technologies in a Vehicular Scenario

“…They conclude that the estimation process is significantly affected by rapid changes of the channel, severely affecting the PER performance, while the Inter-Carrier Interference (ICI) has little or no impact on the performance at small data rates. WAVE also has a limited transmission range; simulations carried out by [14] show that only 1% of communication attempts at 750m are successful in a highway scenario presenting multipath shadowing. The MAC layer in IEEE 802.11p has several significant drawbacks.…”