Study Of QoS-Based Routing For Wireless Sensor Networks

In view of the minimum node energy, the energy-consumption on path, delay and channel error in wireless sensor networks, the paper adopts QoS routing to provide the differentiated services both for real-time traffic and best-effort traffic and it is of the key technology to provide differential services and utilize the whole resource effectively for wireless sensor networks. At the precondition of ensuring the QoS request such as reliability, a new distributed QoS routing algorithm according to "the minimum node energies on path / the path's consumption" and "minimum hop counts" has been proposed by extending Directed Diffusion.It is a NP problem to find a routing according to two restrictions, the paper differentiates the two operations and apply heuristic technique to solve the problem. At first, it differentiates the reliability of the two operations. The best-effort traffic requires high correction for the received data and should do best to guarantee the correction, however the real-time traffic also requires low delay of data relay except the correction that is required when flood the interest.Then two gradients-best-effort gradient and real-time gradient--are set up, the data thatsource node sensed will flows to the sink node along the gradients according to different operation. For best-effort operation, how to utilize network resource effectively is the main consideration. It selects the paths those specific values of "the minimum node energies on path / the path's consumption" are appropriate, and then choose the path with "minimum hop counts" from these paths to forward data. For real-time operation, it is essential to forward to the sink node immediately. Therefore we select the paths those hop counts are minimum, and then choose the path with maximum specific values of "the minimum node energies on path / the path's consumption" from these path to forward data.A corresponding simulation model is designed and based on the analysis of result about the simulation, both the reliability of the two operations are achieved according to the results of the simulation; the delay of real-time approaches that of Directed Diffusion; and the lifetime of the two traffic routing is longer than that of Directed Diffusion differently, the new routing protocol balances the energy-cost of wireless sensor networks greatly.