Research On Adaptive Time-slot Scheduling Algorithm In Wireless Sensor Network With Traffic Load

The progress in the wireless communication,computation and microelectronic technology promoted Wireless sensor network(WSN) development enormously.The MAC protocol tries to ensure that two nodes are not interfering with each others' transmissions,and deal with the situation.It shares wireless communication channel. MAC protocol directly affects the lifetime of WSN.The energy consumption of MAC protocol influences on the node data acquisition ability and the network lifetime.It has the very tremendous influence on the sensor network's performance,the most important aim of designing MAC protocol is to reduce the energy dissipated in the network and maximum the network lifetime.Scheduling MAC protocol is mainly based on TDMA.It periodically schedules each node time slot for data transmission.The nodes which are in idle time slots get into sleep in order to save energy.The scheduling MAC protocol can solve the collision re-transmit problem and less control information.But it needs strict time synchronization.It is suitable for the network nodes have more data load and working in continuity.When the scheme based on TDMA assigns the time slot,generally it divides each sub-channel into same time slot.If the network is under the complicated and diversified environment, easily creates the node the time slot waste as well as the node time delay grows.Present MAC protocol based on the time slot doesn't combine with network layer,has not used the routing information for node time slot assignment.This paper in view of the wireless sensor node work under different conditions,unified the network topology,dynamic analysis MAC layer each round nodes needs the time slot size,we proposed two kinds time slot scheduling algorithms based on the node current traffic load.(1)As sensor nodes working in complex multi-hops heterogeneous network,this paper proposes an adaptive time-slot scheduling algorithm(ATSA) based on clustering.ATSA divided the entire network into some clusters,and constructed a data gathering tree in each cluster.Each round,the cluster head schedules the time-slot of nodes according to their traffic load. Simulation results show that the protocol could meet the system requirements in reliability,real-time response and energy efficiency.(2)As sensor nodes working in non-continuous single-hop isomorphism network,a time-slot scheduling algorithm based on nodes' real-time conditions for Wireless Sensor Networks(TRAT) was presented,the algorithm which is based on cluster structure,unifies distributional and the central merit, In this algorithm,the cluster head adjusts the time-slot of nodes according to their conditions,and the energy consumption balancing among nodes was achieved with a low latency.Simulation results show that the algorithm improves the network energy usability and increases the network lifetime,reduces the data packet time delay.