Implemetation And Topology Optimization For 433M Star Low-Power Wireless Network

Internet of things(IOT) is an essential part of the new generation information technology,and also an important stage of the "information age". With the development of IOT, low-power wireless sensor networks have been deployed in industrial areas to increase the efficiency and effectiveness of management and surveillance for its good features, such as low cost and low power.The network topologies of current wireless sensor networks(WSN) are generally mesh-type or tree-type, such as Zigbee. However, the traditional WSN technologies face some problems, such as short distance, worse signal quality and difficult developing, for its complex network topology and poor wireless diffraction ability. So, it is necessary to make research on the star-type WSN, which can be more low-power, low-cost and longer communication distance.Based on 433 M RF technology, we designed a low-power star wireless sensor network, named LPWSN-433 M, and designed the hardware and software of the LPWSN-433 M system. The wireless diffraction ability of 433 M RF technolgy is better than that of 2.4G RF, so the LPWSN-433 M network can be more low-cost, longer communication distance and better signal quality. We formulate the topology optimization problem of the star network LPWSN-433 M as a 0-1 integer programming(IP) problem. We propose an effective method to solve the problem. To illustrate, the proposed method is to decide an optimal placement of the access points(AP) when given the locations of the sensor nodes considering the objective parameters, such as the overall life time, the reliability of the network, the average message delay and the overall cost of the system.Tested by a real LPWSN-433 M in a parking lot with about 200 parking space, the results illustrate that a placement of access points(AP) generated by the proposed algorithm is more effective, compared with one produced by an experienced engineer in a parking surveillance industry.