Power Control MAC Protocol for Wireless Sensor Networks

With the fast development of information technology, the emergence of the Internet has brought great convenience to our lives. Though the Internet, people could browse news, get information, play online games and so on. As a research focus in recent years, wireless sensor network(WSN) has small volume, low power consumption, and can work under bad environment. Perception object, observer and sensor are three key elements of wireless sensor network.Because sensor nodes are always set up in places where people can hardly reach, it’s not easy to change the battery of sensor node when it runs out of energy. Therefore, how to effectively extend the network life cycle is a research focus. This paper mainly discusses the MAC protocols of WSN. From this perspective, the performance of WSN is optimized by improving the MAC protocol..In this article, a new MAC protocol based on power control is proposed. Nodes calculate the optimal transmit power to its neighbor nodes. With that, sensor nodes could save its energy greatly. Besides, a new back-off algorithm is adopted, which can adjust the contention window based on the number of failed to seize the channel and handle the back-off time properly. It can decrease the collisions’ probability of the data packet and reduce the idle listening time effectively. Also it could effectively improve the channel access fairness and network throughput. Finally, according to the number of data packet in the transmit queue, nodes adaptively adjust the duty cycle, which decrease the data packets’ end-to-end delay under the condition of high traffic load.At last, The NS2simulation results show that the new MAC protocol proposed in this paper has shown lower energy consumption than the SMAC protocol.