Practical Design Of Wireless Sensor Network And Implementation Of Communication Protocol

Recent years, as wireless communication technology develops rapidly, the cost become cheaper and cheaper, so wireless communication technology is used in more and more fields. Wireless sensor network is an important application branch. Wireless Sensor Networks is a multi-hop and self-organizing network system which many low-cost sensor nodes are placed in one monitoring area and organized by wireless communication technology. Sensor nodes complete some data collection works, and send data to network by sensor network, and at last this data is disposed by specific applications.Etung Technology Co., Ltd. designed a monitoring system based on wireless sensor network. The author is responsible for design of communication protocol and software of sensor and repeater. The main topics of this subject are as follows:1) The overall design of the system. The basic elements of the system include three nodes:sensor, repeater, and receiver. This section focuses on hardware and software solutions of these three types of node. Hardware solutions focused on the representation of each chip. Software solutions focused on the individual software modules.2) Design of communication protocol. The network topology of this subject is a hierarchical network topology of the star structure. MAC protocol is based on time division multiplexing and combination of methods based on periodic calls. There are two types of modes:quick routing mode and work mode. Quick Routing mode network is mainly to accelerate the building of the network. The work mode is to collect data from each sensor node, this model also has ad-hoc network function, but the speed is much slower than quick routing mode.3) Software design of sensor and repeater. Software design includes bootload, drivers, and communication protocol. Because these two types of nodes are used the MSP430 MCU, so the development of bootload and drivers are the same. While two types of nodes in the network's role are different, so the development of communication protocol is independent. Software design of Communication protocol in the system development uses the state machine, so the main missions are to design the kinds and relations of the states. Implementations of Each state are simple and software structure is clear, this part also is divided into quick routing mode and work mode.