Wireless Sensor Network Mac Protocol

Nowadays, with the constant development of scientific research and technology, the intersection of different subjects and technology penetration become researchers'researching hotspot. Because some challenging problems of the objective world, only depending on a single technology, are difficult to be solved. They often are completed by more comprehensive technologies. Obviously, facing the real life'different applications, wireless sensor networks are also no exception. Wireless sensor networks with intelligence, miniaturization and multi-function are a set frontier technologies of sensors, micro-electro-mechanical system and telecommunications technology. Because of wireless sensor networks itself characteristics, They have been widely used in various fields.Medium access control(MAC) layer which is located at the bottom of the wireless sensor networks architecture, is a part of data links layer. Its primary responsibility is to control medium access and establish reliable communication links between sensor nodes, and decide the use of wireless channel in wireless sensor networks. Medium access control protocol will indirectly impact wireless sensor networks performances, consequently, how to design MAC protocols which are suit for different applications needs further exploring problems in the future. We mainly discuss MAC protocols'saving-energy in wireless sensor networks in the paper.In this paper, Sensors medium access protocol(SMAC) based on competitive MAC protocols uses periodic sleeping and listening scheduling mechanism, fixed sleeping may reduce the energy consumption, fixed listening is used to transmit lots of data. Because SMAC protocol with fixed periodic sleeping and listening is not suit for dynamic changes of network flows, we put forward R-SMAC based on SMAC, which can adapt to dynamic changes of network flows. A monitoring area is divided into two parts, respectively a intensity task area and a slight task area. We use different communication mechanisms in two areas, which use dynamic sleeping and listening in slight task area and employ time division multiple access according to the spatial multiplexing system in the intensity task area. Lastly, we conclude a modified protocol (R-SMAC) is more improving than IEEE 802.11 and'SMAC protocol in energy-saving aspect in wireless sensor networks by NS2.