Implementations And Optimization Study On Wireless Sensor Networks Based On Contiki Operating System

Wireless sensor network is a self-organized network that consists of plenty of sensors distributed from space communicating in wireless. It can be applied to various fields in daily life and production by integration with specific sensors. The purpose of this thesis is to argue that the wireless sensor networks should gain access to IP network, the nodes inside should be seen as normal network devices which can be visited by PC as well as other general network devices directly, in absence of a gateway. With hardware platform CC2530, the Contiki OS and built-in network stack developed by Sweden scholar Adam Dunkels are introduced. The working principle of Contiki OS is given. Layered network protocols and the relations in between are carried out carefully. Then I integrated sensors to the CC2530platform and established a network by which host PC would visit the sensor node based on IP. And a node based on CoAP protocol could be visited through IP was designed and implemented. Finally, a latency performance of CoAP protocol is given. A solution to reduce latency when fetching resource information on CoAP Server is also proposed.