دانلود رایگان مقاله طرح انتخاب تطبیقی گره های رله برای پخش مولتی هاپ در VANETs

abstract

Vehicular ad hoc networks (VANETs) have potential applications for improving on-road driving experiences including preemptive road safety measures and provision for infotainment services. This paper proposes a Bi-directional Stable Communication (BDSC) relay nodes selection scheme designed for multi-hop broadcasting protocols over a platoon of vehicles. Relay nodes selection is based on quantitative representation of link qualities for single-hop neighboring nodes by using a proposed link quality estimation algorithm. The BDSC scheme aims to improve packet delivery ratio while maintaining low end-to-end communication delays over a densely populated network with nodes distributed over a large coverage area. To achieve this, the proposed scheme attempts to adaptively balance between the estimated link qualities and the distance between the source broadcaster and the potential forwarders when selecting the next hop nodes for relaying the broadcast messages. Our results from extensive simulation analysis reveal that the proposed BDSC scheme outperforms existing multi-hop broadcasting schemes in terms of packet delivery ratio when evaluated over a densely populated VANETs.

6. Conclusions

This paper has proposed a new multi-hop message broadcasting scheme over a platoon of vehicles forming a VANET. The scheme, referred to as Bi-Directional Stable Communication (BDSC), aims to improve the packet delivery ratio over densely populated VANETs and at nodes positioned at far distances from the broadcasting source. The BDSC scheme utilizes a forward link quality estimation algorithm that periodically provides quantitative representations of the link qualities between the current broadcasting source and the set of potential relay nodes. A link selection criterion is devised within the proposed BDSC scheme that attempts to take into consideration the estimated link qualities of potential relay nodes and their corresponding distances from the current broadcaster when selecting the next relay forwarding node. In addition to improving the packet delivery ratio, the suggested BDSC scheme also attempts to obtain low end-to-end delays and high saved-rebroadcasts over densely populated VANETs. The performance of the proposed BDSC scheme has been evaluated over both low and high node density VANETs. In order to study the impact of varying data traffic, three different background traffic scenarios have been adopted in which 10%, 50% and 100% of the total nodes participate in generating the background traf- fic. Our results have demonstrated that the BDSC scheme outperforms existing similar solutions in terms of packet delivery ratio at high node density networks and increased background traffic. Furthermore, the BDSC scheme exhibits the lowest end-to-end delays over all considered background traffic scenarios. The superior performance characteristics exhibited by the BDSC scheme, in terms of packet delivery ratio and end-to-end delay, are obtained while maintaining comparable saved-rebroadcasts to that obtained by the existing furthest distance scheme. A trend of higher resilience to messages loss, as reflected by the achieved high packet delivery ratios, is observed by the proposed BDSC scheme. The BDSC scheme can serve as an important building block for multi-hop message dissemination protocol for many applications in VANETs, such for safety-related alert messages and traffic management services.