Wireless Sensor Network Measurement And Congestion Control Technology Research

Wireless sensor network collected data from the edge of the monitoring area to the data collection center(Sink nodes)with mult i hop transmission convergence.The data flow and collisions of nodes close to sink are increasing and resulting in funnel effect.In the funnel area,the overhearing phenomenon exacerbated the node level congestion,reduce the network throughput,increase energy consumption and shorten the lifetime of the whole network,affect the transmission performance of the network seriously.Therefore,research on the control technology of congestion has become the key to increase the performance of wireless sensor networks.This paper reaserches on the factors of congestion inside node by measuring the wireless sensor node,which is designed by ourselves,and propose the heterogeneous-bit-rate transmission network to control the congestion,the main work is as follows:1.A wireless sensor network measurement platform has been designed and implemented in real environment,including the sensor node composed by ATmega128 microprocessor and RF chip CC1100,and the data collected software,which enable the data of packets,including the number,RSSI,LQI and so on,be collected and stored in PC by using a serial port,then analyzed with MATLAB software.2.A wireless sensor simple multi hop network has been deployed in the actual environment,this paper use the logic analyzer to measure the SPI,serial port pin of node in real time during data transmission and reception,and analyze the time sequence of inside nodes,includes two aspects : CSMA measurement,SPI-serial port measurement.Observe the interval of the packet sending with CSMA mechanism and analyse rationality of backoff window size;through the measurement of SPI and serial port,observed the data nodes inside node in precise timing,analyse the overhearing phnomene that resulting in congestion.3.Analyse of internal nodes the congestion problem caused by overhearing in the wireless sensor network data base on the queuing theory model,and points out that the packet to reduce the overhearing can effectively reduce the node level congestion.Put forward the heterogeneous-bit-rate transmission network,constructing a hierarchical network with different bit rate,shielding overhearing packets inter-path and intra-path.Improving components and interfaces to achieve new TinyOS system that enable sensor nodes support heterogeneous-bit-rate communication and the corresponding network establishment and maintenance scheme.Build a heterogeneous bit rate network in the actual environment with a variety of topological structure and different flow conditions,the results show the throughput,packet reception rate,packet loss rate network performance in heterogeneous-bit-rate network has been optimized.