Balancing wireless data broadcasting and information hovering for efficient information dissemination

Wireless data broadcasting is an efficient, bandwidth preserving way of data dissemination. However, as the amount of data increases, the waiting time of the clients becomes unacceptably high. The present paper proposes the combination of optimal wireless broadcasting and information hovering, as an effective means of performance improvement in vehicular networks with locality of demand. While state-of-the-art works exploit user collaboration only as a means of wireless coverage extension, the proposed scheme proposes parallel dissemination through broadcasting and user networking over the whole studied area. Optimal, periodic broadcast scheduling is adopted at the highest tier for data dissemination. At the lowest tier, users can exploit information hovering around selected anchoring points, in order to retrieve data faster than their next scheduled broadcast. The issue of sharing the dissemination load optimally between the broadcasting and the hovering subsystems is mapped to the classic pull-push balancing problem. Through analysis, the long-standing optimal cut-off point balancing method is shown to be suboptimal, and a new method is proposed which achieves lower client serving time in any of the cases. Simulation results in realistic VANETs show that the proposed dissemination scheme surpasses state-of-the-art works in terms of efficiency and client satisfaction.