| WSN (Wireless Sensor Network) is a product that unifies Micro-Electro-Mechanical Systems, communication, sensor and network technologies. At present it already is foreseen that it would have widespread application domain and high value. However, WSN is a kind of network with limited resource. So the computing capability, memory and energy of the node are very limited, especially for energy. Therefore, the main problem of WSN is how to design some efficient strategies to make the life of network longer. To solve such a problem, this dissertation firstly introduces the design and implement of a kind of low power intelligent node based on CC2420 and a kind of Sink with GPRS. Then, this dissertation introduces some design and research work on routing protocol, MAC and positioning technology based on the hardware platform.On the base of Minimum-hop routing protocol, this dissertation classifies neighbor nodes into three kinds. The current node chooses the corresponding kind neighbor node as the next hop according current condition. In addition, this dissertation proposes a scheme alarming node dying. Then this dissertation analyzes the performance of improved protocol and simulates it on computer. Simulation results show that lower network load and longer life are acquired by the improved protocol.To figure out the latency problem of S-MAC, this dissertation proposes some improved methods such as adaptive listening, ahead transmitting and ahead sleeping, and also tests the performance of the improved S-MAC on the hardware platform. Test results show that: the improved S-MAC is energy-efficient but with short latency.Furthermore, using the hardware platform, this dissertation designs and implements a kind of positioning algorithm based on RSSI and the maximum likelihood estimate, and then tests the performance of this algorithm. Test results show that the absolute value of error for this algorithm is less than 3 meters, which meets the positioning requirement of WSN. |
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