SINR-Based Analysis of IEEE 802.11p/bd Broadcast VANETs for Safety Services

The safety-critical applications of vehicular ad hoc networks (VANETs) require high reliability and low transmission latency. IEEE 802.11p and IEEE 802.11bd are two standards proposed for such vehicular communication systems. In this paper, we propose an effective SINR-based model to conduct the QoS analysis of IEEE 802.11p/bd driven VANETs for safety applications. First, a semi-Markov process (SMP) model with a D/G/1/1 queue is tailored and modified for characterizing channel access behavior of IEEE 802.11 broadcast networks with deterministic message generation rate. Then, a novel approach is developed to derive the distribution of signal-to-interference-to-noise ratio (SINR) on each receiver in the VANET, given general channel fading/shadowing models as well as general node geometry distributions. Consequently, various QoS metrics in Physical/MAC/Application layer of VANETs are defined and evaluated. Compared with the existed analytic SINR-based models for broadcast VANETs, the proposed models are more general, more accurate, and are faster to solve. Finally, a new mechanism is shown to map the performance in physical layer into the QoS quantification in higher layer so that the QoS prediction of IEEE 80211bd driven VANETs is enabled. Furthermore, comparison between 802.11p and 802.11bd is conducted regarding how the stringent QoS requirements of selected safety applications in both human driving VANETs and autonomous driving VANETs are met by the two communication systems. Constructive conclusions are given on the suitability of IEEE 802.11bd for VANET critical safety services and the directions of future development.