The Key Technology Research Of WIFI Sensor Network Data Transmimission With Low Poewr

Wireless sensor network has been widely applied in many fields.The rate of traditional wireless sensor network based on Zigbee is limited.In the large data transmission multi-node Ad-hoc network applications,low power technology based on WiFi wireless sensor network has attracted much attention.In this paper,research and solve the key problems during building the WiFi low power wireless sensor network,which is applied on field data collection,whose characters are large scale network,high node density and node data more concurrent transmission.The hidden terminals in the CSMA/CA mechanism based on WiFi channel access will cause serious competition conflict,causing a sharp drop in the efficiency of the network.This paper studies a kind of low conflict and low-power MAC mechanisms.At the first,this paper designs a way based on the node location,which divides the terminal nodes into different clusters with cluster strategy.Then time-share scheduling these clusters.This action can reduce the hidden terminal competition caused by the conflict.At the same time introduce the sleep mechanism in the time slot polling day.It can reduce the power consumption of the network.Simulations show that the algorithm is compared with the traditional CSMA/CA mechanism and the success rate improves about 40%,power consumption reduced by 50%or so.And then to search the prototype of low power WiFi ad-hoc network node,realize the MAC layer distributed coordination function on the FPGA.The system mainly divided into sending engines,receiving engine and control ing the state machine.Sending the engine according to the state machine instructions will be sent message.Receiving engine will unlock message from the lower back,and report to the state machine with information.The state machine according to indicator change the node stateFinally based on Zedboard platform structures,realize the node MAC protocol testing system.It divided into upper machine and lower machine.PC receive and display the MAC layer of sending and receiving data through the network.Lower machine's MAC protocol sends and receives data based on the physical level of 802.11b.