Enhancing connectivity for spectrum-agile Vehicular Ad hoc NETworks in fading channels

Abstract

In Vehicular Ad hoc NETwork (VANET) safety applications, connectivity among vehicles is important to disseminate the upcoming traffic information (e.g., warning messages generated by a source vehicle that detects an accident) to other following vehicles to notify drivers in a timely manner. Because of the highly dynamic VANET topology and the short transmission range mandated for Dedicated Short Range Communication (DSRC) by Federal Communications Commission (FCC), communication links among vehicles are short-lived especially in sparse vehicular density, making the task of establishing (through connection setup process) and maintaining the communications for fast-moving vehicles difficult. Furthermore, when a fixed transmission range is used in dynamically changing VANET, network could be easily suffered by a "broadcast-storm" in dense vehicular density while vehicles in VANET could be disconnected frequently in sparse vehicular density. In addition, when communication channels are overcrowded in VANET, vehicles should be able to switch from one radio frequency (RF) bands to another to make robust communication using spectrum-agile wireless environment. In this paper, we study the connectivity for spectrum-agile VANET in fading channels. Specifically, connectivity enhancement for vehicle-to-vehicle communications for vehicles traveling in opposite directions and for vehicles traveling in same direction is investigated using mathematical analysis and simulation results. Performance of the proposed approach is evaluated using numerical and simulation results.Index Terms-Vehicle-to-vehicle connectivity, connectivity in VANET, spectrum-agile VANET, adaptive VANET.

Inter Vehicle Distance Based Connectivity Aware Routing in Vehicular Adhoc Networks

“…Although the idea of maintaining connectivity using bio-inspired technique looks quite promising, yet non-inclusion of mathematical modelling reduces the applicability of the approach. Connectivity enhancement for spectrum-agile VANETs has been investigated considering fading channel scenario [32]. Connectivity in bi-directional traffic is derived in terms of probability of summation of channel sensing, channel switching and data exchange times is less than or equal to the time available for communication which depends on the transmission range and speed of communicating pair of vehicles.…”

Towards intelligent transportation Cyber-Physical Systems: Real-time computing and communications perspectives

“…If a given vehicle has options to use different wireless networks, it should be able to choose the best network suitable for exchanging information over the network [7,9,10,17,18]. As per the DSRC requirement in road transportation, each vehicle is required to broadcast its periodic status information (which includes, its speed, accelaration, geolocation, direction, etc.)…”

“…Transportation CPS is one of them where feedback for control through wireless communication is one of the major components for both safety and infotainment applications. Vehicles exchange information using vehicleto-vehicle (V2V) through vehicular ad hoc network (VANET) and/or vehicle-to-roadside (V2R) communications [7,9,10,17]. For wireless communication IEEE has 802.11p standard for Dedicated Short Range Communication (DSRC) for Wireless Access for Vehicular Environment (WAVE).…”

The impact of secondary user mobility and primary user activity on spectrum sensing in cognitive vehicular networks

“…The probability distribution of existence of a link (so that an SU can sense the channel) between two vehicles separated by a distance d is log-normal and is given by [15] …”

“…Note that the speed of different vehicles in free flow state is a Gaussian distribution [16], and for v min = µ v − 3σ v and v max = µ v + 3σ v as minimum and maximum level of the vehicle speed, the probability density function (PDF) is given by [15] …”