Multi-channel Mac Protocol Of Wireless Sensor Network Research And Realization

In Wireless Sensor Network (WSNs), medium access control (MAC) protocolsdetermine the usage mode of wireless channel, allocate limited radio resourceamong sensor nodes and construct infrastructure. MAC protocols have a greatinfluence on the WSNs performance. MAC protocols of traditional wirelessnetworks can't meet the design requirements for WSNs, and can't be useddirectly. So research on MAC protocols of WSNs always attracts a lot ofattention.Firstly, the structure of WSNs is introduced in this thesis overall. Thenwe discuss the existing MAC protocols and the keys of MAC protocols, andanalyze the differences among them. Then a new multi-channel MAC protocolnamed DCA-CRM for WSNs is designed, which adapts to the special networkapplication, and the dynamic channels assign mechanism and power control isused in it. Nodes can adjust their transmit power based on the distance of thereceiver. And a virtual frame mechanism is designed to support biggernetwork's packets. The MAC protocol is also compatible with the physic layerof IEEE 802.15.4 standard. Then DCA-CRM is implemented in ANSI C, based onSARD IC boards which are developed by Freescale corp.. Afterwards, we design4 experiments to verify the attributes of DCA-CRM, and compare them with manyclassic MAC protocols'. Finally the thesis draws a conclusion by summarizingthe research and presenting directions for future work.The results of research show that, the new MAC can completely solve thehided-ends and exposed-ends problems, can improve energy savings, the meanthroughput and network lifetime.