Multi-Constrained Routing Algorithm for Multimedia Communications in Wireless Sensor Networks

The existing routing protocols designed for real-time or multimedia applications in sensor networks usually adopt relatively simple routing models where fewer service metrics are considered, which is not sufficient for real-time or multimedia data transportations. Furthermore, for the sake of route discovery or the acquisition of a target location, they usually need extra localization equipments or beacon exchanges to obtain the geographic location of each sensor node or construct a coordinate system for sensor nodes, which imports extra costs to routing algorithms. In this paper, firstly we propose a novel system model that can comprehensively depict the service requirements of multimedia applications, and on the basis of this system model, we design a new multi-constrained routing algorithm, MCRA, for multimedia communications in sensor networks. MCRA not only can provide end-to-end delay guarantee and packet loss ratio guarantee for multimedia communications, but also can balance and improve the energy consumption in sensor nodes. Besides, MCRA adopts several effective policies to suppress message flooding and lessen data redundancy. In MCRA, neither the acquisition of target location nor the route discovery process requires any extra measurement equipment or coordinate system based on location message exchange, however, the target location we concern can be easily figured out by a localization scheme without message exchange. In addition, we may optionally apply MAC multicast and differentiation service in MCRA so as to further lower its control message overhead and differentiate forwarding priority levels for real-time data and best-effort traffic in MAC layer. Theoretical analysis and simulation experiments are provided to validate our claims.