| Wireless Sensor Network (WSN), which is made by the convergence of sensor, embedded computation, networks and wireless communication technologies, is a novel technology for acquiring and processing information. It is a late-model wireless networks of infrastructureless network and can be used for testing, sensing, collecting and processing information of monitored objects. Wireless sensor networks becomes a new research area and has a bright future in application. Both academia and industries are very interested in it. Wireless sensor networks are listed by in 10 emerging technologies which will change the world by"Technology Review"."IEEE Spectrum"also expects that WSN will make a huge influence on people's lives.Since WSN don't rely on any infrastructure, self-organization algorithms are indispensible. When a sensor node enters the working region, it acquires nothing but one-hop neighborhood information via MAC and physical layer protocols. It is impossible to get the topology information about the whole network. Network algorithms effectively organize sensor nodes and take advantage of cooperative effort of sensor nodes to fulfill a specific task. The implementation of routing algorithms, transport protocols and applications is based on MAC protocol algorithms.In the four parts of the thesis,we conduct a deeply research on wireless sensor network MAC protocol:In the first part of the work, we propose the difference between WSN and traditional networks, not only given the characteristic of WSN, we also have illustrate the research orientation in this area. In the second part, the existing MAC protocols are classified and both the advantages and disadvantages are analyzed, we mainly focus on the analysis of the contend based MAC protocols, and have a deeply insight of SMAC and TMAC, which are the most important protocols nowadays.In the third part, we introduce the Power Control mechanism, it is matured in CDMA system,While researchers have found its potential in WSN area, and we also discuss several important power control protocolsIn the fourth part, a power control MAC protocol (DPPC-MAC) for wireless sensor networks is proposed. The new protocol is based on SMAC,and introduces power control mechanism for energy saving. The main contribution of our work is to propose a new approach—distance prediction algorithm—for determining the transmission power to preserve the collision, increase goodput and solve hidden/exposure terminal problem. Simulation results show that DPPC-MAC can provide better energy efficiency and throughput than current important protocols.At the last part of this dissertation, the whole work of the dissertation is outlined and the further research issues are discussed. |
