Recently data dissemination using Road Side Units (RSUs) in Vehicular Ad Hoc Networks (VANETs) received considerable attention for overcoming the vehicle to vehicle frequent disconnection problem. An RSU becomes overloaded due to its mounting location and/or during rush hour overload. As an RSU has short wireless transmission coverage range and vehicles are mobile, a heavily overloaded RSU may experience high deadline miss rate in effect of serving too many requests beyond its capacity. In this work, the authors propose a co-operative multiple-RSU model, which offers the opportunity to the RSUs with high volume workload to transfer some of its overloaded requests to other RSUs that have light workload and located in the direction in which the vehicle is heading. Moreover, for performing the load balancing, the authors propose three different heuristic load transfer approaches. By a series of simulation experiments, the authors demonstrate the proposed co-operative multiple-RSU based load balancing model significantly outperforms the non-load balancing multiple-RSU based VANETs model against a number of performance metrics.
TopConsiderable researches have been carried out to find a stable data dissemination infrastructure in highly mobile and sparsely connected VANETs environments (Chen, Kung, & Vlah, 2001; Wu, Fujimoto, Guensler, & Hunte, 2004; Zhao, Zhang, & Cao, 2007; Zhao & Cao, 2008). Nadeem, Shankar, and Iftode (2006) formulate a data push communication model for vehicle to vehicle communication without any road side infrastructure support. Zhang, Zhao, and Cao (2010) provide a single RSU-based VANETs model which maintains both upload and download queues and try to get the service balance among them. Yi, Bin, Tong, and Wei (2008) provide a mesh RSUs infrastructure based VANETs on both space and time dimensions and formulate reliability and fairness based algorithms. Ali, Chan, and Li (2011) analyze the performance of different on-demand scheduling algorithms for incorporating upload queue with download queue in RSU-based VANETs. Chen, Cao, Zhang, Xu, and Sun (2009) study the performance of the effectiveness of certificate revocation distribution in VANETs with and without enabling vehicle to vehicle communication. Liu and Lee (2010) analyze dynamic traffic characteristics in RSU-based VANETs. They propose to use different channels to disseminate different types of data and apply push and pull data dissemination technique based on the volume of requests at RSU server.
Some researchers study the performance of on-demand scheduling algorithms for data dissemination in real-time environments (Lee, Wu, & Ng, 2006; Liu & Lee, 2010; Xu, Tang, & Lee, 2006; Wu & Cao, 2001).