The Research And Application Of Wireless Sensor Networks Based On Contiki Operating System

In the upcoming 5G(5th-Generation)era,the network will have a higher speed,lower latency and lower power consumption,and the need of massive wireless communication by the Internet of Things will also be satisfied.At the same time,the industry ecology of International Internet of Things is accelerating layout,the standardization of the Internet of Things technology is also continuing to advance;In our country,the concept of "Internet+" put forward by Premier Li Keqiang is heating up.The development of Internet of Things in our country is entering the fast lane.The development tendency home and abroad shows that the applications of Internet of Things including the Internet of Vehicles,Smart home,Smart city and so on is on the eve of leapfrog development.WSNs(Wireless Sensor Networks)is one of important application and research fields of Internet of Things,will combined with our life more closely,and to be the next tremendous opportunities.Now the number of IP based embedded devices also is fast multiplying as the WSNs develops.In the near future,as the micro wave of devices,the Internet will further permeate every sphere of our lives.Then the WSNs will become an integrated part of the Internet.The WSNs studied in this paper is based on Contiki Operating System,the Contiki realized the IP of the sensor network nodes.Every node in the WSN has an IP,directly connect to the Internet with the low power and low bandwidth wireless network.WSN nodes usually powered by battery.How to make the nodes run at low power at the same time guarantee the quality of service is the key to successfully deploy the WSN.And it is also a major challenge.MAC(Medium Access Control)is one of the most importent protocols in the WSN.It controlls the radio module of the WSN nodes,and is the key part of the energy efficiency of the nodes.So,the research and improvement on the MAC is an important way to prolong the life time of WSN nodes.This paper studies the low power of the WSN based on the Contiki RTOS(Run Time Operating System).In this paper,I reduce the power consumption of the nodes and improve the network Qo S by improving the Contiki MAC,which is the default MAC protocol of Contiki.At the same time,aiming at the problem of the internetworking on the Internet and WSN,I design and implement a proxy gateway.It solves the problem of internetworking on application layer.The research works in this paper mainly focus on the following aspects:1.This paper studies the WSN and Contiki operating system.Including principle of the Contiki modules and relevant protocols about the IP of WSN,such as 6Lo WPAN(IPv6 Low Power Wireless Personal Area Network),Co AP(Constrained Application Protocol)and so on.2.Improve the Contiki MAC protocol.The Contiki MAC duty-cycling is based on periodic wake-up of nodes with static RDC frequencies,which can not adapt to the network load and the change of the node power.This paper presents a new improved scheme to adjust the frequency of RDC through the traffic load and the battery power of the nodes.The improved Contiki MAC reduces the power consumption of the nodes,prolongs the life time of WSN,and improves the network Qo S.3.The research and implementation of the Co AP gateway.The application protocol of WSN--Co AP and the application protocol of Internet--Http can not communicate with each other directly,and the Internet application can support Co AP is very few.At the same time,the Internet is still based on IPv4,can not completely matching the WSNs based on IPv6.I design a gateway of Internet of Things by reusing the existing networks standard protocols.This gateway implements the application layer interconnection between the Internet and the WSN nodes.Meanwhile,the gateway provides a caching mechanism.The caching mechanism minimizes the traffic in the WSN,reduces the power consumption of the nodes,and prolongs the life time of the WSN.