Fast Response Enhanced Multi-queue packet Scheduler scheme for Wireless Sensor Network

摘要

Wireless Sensor Network (WSNs) interact with critical physical environments, one of the critical issues of WSNs are real time consideration. Existing WSNs suffers from lack of real time task allocation In support of in support of real time communication. In WSNs especially for real time applications efforts to reduce energy consumptions, end to end transmission delay must be considered. Though various ways like data aggregation are existing, packet scheduling is more important as it assures the delivery of various types of packets depending upon the priority. Many wireless sensor network (WSN) applications heavily rely on information being transmitted in a timely manner. In such sensor networks, packet scheduling plays a vital role in reducing endtoend data transmission delays. It also helps in reducing sensors energy consumptions, thus increasing the lifetime of the wireless sensor network. The simplest packet scheduling scheme is FCFS (First Come First Serve). Many more packet scheduling schemes have been proposed for wireless sensor networks such as EDF(Earliest Deadline First) and those based on priority with single and multiple queues. In this paper we discuss Fast Response Enhanced Multiqueue Packet Schedular Scheme for Wireless sensor network. In Sensor Network each node, except those at the last level of the virtual hierarchy in the zone based topology of WSN, has three levels of priority queues. Realtime packets are placed into the highestpriority queue and can preempt data packets in other queues. Nonrealtime packets are placed into two other queues based on a certain threshold of their estimated processing time. Leaf nodes have two queues for realtime and nonrealtime data packets since they do not receive data from other nodes and thus, reduce endtoend delay. Data packets sensed by nodes at different levels are processed using a TDMA scheme.