Utilizing road-side infrastructure for location-based services in vehicular ad-hoc networks

Location-based services (LBS) can be treated as an abstraction of spatial queries, e.g. k-nearest-neighbor (k-NN) queries. In LBS, users retrieve their desired entertainment services and information from their mobile devices based on their geographical position at the request time through mobile network. The IEEE standardization of Dedicated Short Range Communication (DSRC)/Wireless Access in Vehicular Environments (WAVE) is designed for high-speed vehicle-to-vehicle and vehicle-to-infrastructure communication in vehicular ad-hoc networks (VANETs). However, most existing VANET-based LBS are designed for simple applications like information dissemination. In this paper, we develop a VANET-based LBS with the utilization of RSUs as an infrastructure support to process k-NN queries. In our framework, we design road-based semantic broadcasting and scheduling methods for RSUs to pour useful information into the network, and a communication protocol to handle incomplete transmission between vehicles and RSUs. We evaluate our framework with and without RSUs through simulated experiments. Experimental results show that the utilization of RSUs significantly improve the query response time, query answer accuracy, and communication overhead.