Evaluation of the LORA-CBF Routing Algorithm with Selective Gateway in an Ad Hoc WiMAX Network

Introduction

Vehicles are an important tool in everyday life. In fact, in major cities, people spend an important part of each day in their vehicles, either driving or stuck in traffic jams. Today, there are many existing technologies designed to make vehicular road travel safer, easier and more enjoyable (e.g. geographical positioning system, proximity sensors, multimedia communication). Despite these advances, however, the impact of these devices in the areas of comfort and safety is somewhat limited because the information gathered by these cannot be share among vehicles, due to a lack of network connectivity. Therefore, the great challenge for these kinds of networks is to meet the issues placed on both the medium access and routing algorithms.

In order to share data more effectively and dynamically in applications, thus improving passenger safety, convenience, and comfort, protocols and network devices must provide both timely and reliable data transfer among vehicles. Deploying network devices in vehicular scenarios represents a huge technical challenge that involves every layer of the communication model; however, this is particularly important for the lowest three layers (i.e. physical, medium access and network). This is primarily due to the highly dynamic network environment, characterized by the constant entry and exit of nodes, and the difficulty of handling highly dense vehicular networks (Aquino, Gonzalez, Villaseñor, &Crespo, 2009; Aquino, Gonzalez& Villaseñor, 2008; Aquino, Rangel & Edwards, 2008; Aquino & Edwards, 2006).

According to Briesemeister,Schäfers & Hommel, (2000), the highly dynamic nature and multiple demands imposed on vehicular networks means that participating nodes must:

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  have radio transceiver technology that provides omni-directional coverage

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  be capable of rapid vehicle-to-vehicle communications to keep track of dynamic topology changes

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  possess highly efficient routing algorithms that fully exploit network bandwidth.

However, unlike other scenarios, nodes in vehicular networks undergo constant and rapid change. In conventional networks, nodes can move slowly or even be static, however, in vehicular scenarios, the network topology can change in a fraction of a second. For example a car accident can turn a highway scenario where vehicles are free to move from lane to lane at speeds exceeding 90km/h to a city scenario where travel speeds can be extremely restricted and movement between lanes is impossible.

This chapter presents the challenges of incorporating WiMAX and geographic routing (i.e. LORA-CBF) in vehicle-to-vehicle multi-hop networks. We believe that a mixture of geographic routing algorithm that is supported by a WiMAX layer can outperform proposals explored until now in vehicle-to-vehicle networks.

This chapter also compares Ad hoc On-demand Distance Vector (AODV) and Location Routing Algorithm with cluster based flooding (LORA-CBF) in a static, dense scenario in WiMAX-mesh mode as the first step in order to develop a fully mobile communication subsystem.

The rest of this chapter is organized as follows, Section 2 is an overview of the literature of VANETs and WiMAX related proposals as well as a brief review of routing protocols in VANETs, Section 3 presents LORA-CBF algorithm, in Section 4 the simulation setup is described, Section5 shows the analysis of the gathered results and finally in Section 6 the chapter conclude.