New design of wireless ad-hoc network (WAHCN) for motorway monitoring system

Abstract

Motorway surveillance system is one of the most important technologies used today to collect information about traffic conditions. Traditional camera motorway surveillance systems are based on wired or infrastructure wireless network technology; whereby the system is designed to send the information (images) to a predetermined location (the “Base Station”). The traditional system does not provide effective access to the surveillance system network for motorway users. In this thesis a newly designed motorway surveillance system network called Wireless Ad Hoc Camera Network (WAHCN) is proposed, modeled and analyzed. WAHCN enables motorway users to access image data taken by a network of cameras placed along the motorway. It provides improved safety awareness by allowing motorway users to view traffic and road conditions. The topology design of WAHCN imposes several constraints on the amount of images can be transmitted through the network depending on the size and the rate of the packets generated by each camera. Moreover, the results showed that the WAHCN provides better performance for vehicle speeds of less than 120 Km/h. A new protocol based on transmission range of the nodes is developed to effectively manage the operation of selecting, finding and requesting the desired camera without using GPS. This protocol is called Selecting and Finding Position (SFP) protocol and provides an effective way to acquire images from any camera within the WAHCN. Routing in any network system is a critical task, especially for WAHCN due to the highly dynamic environments. Different types of routing protocols may give different network performance due to the different functional mechanisms of these protocols. The performance evaluations, comparisons, and analysis for three routing protocols (AODV, DSR, and OLSR) for WAHCN are presented in this thesis. The evaluation and analysis are performed for different performance metrics and under different network conditions. The results showed that under various vehicle speeds and different network loads AODV outperforms DSR and OLSR protocols, with respect to network throughput (by 35.11% and 10.24%, respectively) and protocol overhead (by 20.51% and 57.38%, respectively). From these results a new routing protocols is proposed and called Modified AODV (MAODV). MAODV protocol has all the characteristics of the original AODV protocol since it follows all the steps of the route discovery and route maintenance mechanism of the original AODV. In MAODV, one of the cameras which belongs to the old route is forced to start the process of rediscovering a new path to the unreachable destination instead of the source node when link breakage occurs. The modification of AODV reduces protocol overhead and packet transmission time delay, which leads to an improvement in WAHCN performance.