Self-Stabilizing TDMA Algorithms for Dynamic Wireless Ad-hoc Networks

In dynamic wireless ad-hoc networks (DynWANs), autonomous computing devices set up a network for the communication needs of the moment. These networks require the implementation of a medium access control (MAC) layer. We consider MAC protocols for DynWANs that need to be autonomous and robust as well as have high bandwidth utilization, high predictability degree of bandwidth allocation, and low communication delay in the presence of frequent topological changes to the communication network. Recent studies have shown that existing implementations cannot guarantee the necessary satisfaction of these timing requirements. We propose a self-stabilizing MAC algorithm for DynWANs that guarantees a short convergence period, and by that, it can facilitate the satisfaction of severe timing requirements, such as the above. Besides the contribution in the algorithmic front of research, we expect that our proposal can enable quicker adoption by practitioners and faster deployment of DynWANs that are subject changes in the network topology

Maximizing Throughput of Linear Vehicular Ad-hoc NETworks (VANETs) -- a Stochastic Approach

International audienceIn this paper we use stochastic geometry to propose two models for Aloha-based linear VANETs. The first one uses Signal over Interference plus Noise Ratio (SINR) capture condition to qualify a successful transmission, while the second one expresses the transmission throughput as a function of SINR using Shannon's law. Assuming Poisson distribution of vehicles, power-law mean path-loss and Rayleigh fading, in these models we derive explicit formulas for the mean throughput and the probability of a successful reception at a given distance. Furthermore, we optimize two quantities directly linked to the achievable network throughput: the mean density of packet progress and the mean density of information transport. This is realized by tuning the communication range and the probability of channel access. We also present numerical examples and study the impact of external noise on an optimal tuning of network parameters

Adaptive multi-channel MAC protocol for dense VANET with directional antennas

Directional antennas in Ad hoc networks offer more benefits than the traditional antennas with omni-directional mode. With directional antennas, it can increase the spatial reuse of the wireless channel. A higher gain of directional antennas makes terminals a further transmission range and fewer hops to the destination. This paper presents the design, implementation and simulation results of a multi-channel Medium Access Control (MAC) protocols for dense Vehicular Ad hoc Networks using directional antennas with local beam tables. Numeric results show that our protocol performs better than the existing multichannel protocols in vehicular environment

Vehicle-to-Vehicle Communications with Urban Intersection Path Loss Models

Vehicle-to-vehicle (V2V) communication can improve road safety and traffic efficiency, particularly around critical areas such as intersections. We analytically derive V2V success probability near an urban intersection, based on empirically supported line-of-sight (LOS), weak-line-of-sight (WLOS), and nonline-of-sight (NLOS) channel models. The analysis can serve as a preliminary design tool for performance assessment over different system parameters and target performance requirements