Design Of Field Environmental Monitoring System In Cold And Arid Areas Based On 6LoWPAN

The field environment in cold and arid areas of China contains indispensable resources for national economy,so its strategic position is prominent.Field environmental observation system plays an important supporting role in scientific research in cold and arid areas and in solving the major strategic needs of the country.However,the traditional wireless sensor networks used in the field environmental observation system in cold and arid areas have some drawbacks,such as inadequate address space of the observation network,unable to achieve end-to-end communication with the IP network and so on.Therefore,based on 6LoWPAN technology,a field environmental monitoring system suitable for cold and arid areas is designed in this thesis.This research can solve these problems and make a good technical reserve for the future construction of a cross-disciplinary and cross-regional virtual synchronous joint observation system in cold and arid areas.Firstly,in order to prolong the life cycle of sensor networks deployed in cold and arid areas,this thesis proposes a scheme based on residual energy improved RPL protocol,which is simulated in Cooja simulator.The simulation results showed that the energy consumption of nodes is more uniform and the lifetime of network is prolonged effectively when the network using improved protocol is compared with the network using original RPL protocol.Then,based on 6LoWPAN technology,a field environmental monitoring system in cold and arid areas is designed.The monitoring system designed in this thesis adopts full IP network architecture and uses MQTT protocol to realize application layer communication.It consists of 6LoWPAN nodes,gateway,MQTT server and remote client.The 6LoWPAN node uses CC2538SF53 as the main control chip,and chooses the Contiki system with the6 LoWPAN protocol stack as the software platform.The 6LoWPAN node is mainly responsible for collecting field environment information and executing control instructions from remote clients.The gateway is composed of 6LoWPAN network card and main processor.The main processor is developed with iTOP-4412 development board,and its operating system uses Linux system.The gateway is responsible for establishing and maintaining the 6LoWPAN network.When the 6LoWPAN node requests to join the network,it automatically configures its stateless address.At the same time,the gateway is also responsible for forwarding datagrams between 6LoWPAN network and IPv6 network.The MQTT server selects the MQTT proxy server Mosquitto,and the remote client selects the MQTT client Eclipse paho.The remote client obtains environment information by subscribing to messages published by 6LoWPAN nodes,and sends control instructions by publishing messages subscribed by 6LoWPAN nodes.Finally,this thesis simulates the climate environment in the cold and drought areas in thelaboratory,and tests the monitoring system in detail.The test results showed that the field environmental monitoring system in cold and arid areas can realize end-to-end communication between 6LoWPAN node and host in IPv6 network,and can work stably in extreme environment.Therefore,this study can solve some problems faced by the field environmental observation system in cold and arid areas,and has important significance and value in theoretical and applied researches.