A MAC protocol based on multi-tiered virtual clusters for wireless sensor networks

Wireless sensor networks (WSNs) have various applications to tracing, alarming and monitoring the information in physical world. Environment monitoring applications monitor the temperature, humidity and degree of pollution in wide area periodically. These applications are consisting hundreds and thousands nodes in wide-area. Therefore scalability is important with energy efficiency. We propose a new MAC protocol for environment monitoring applications in WSNs. Proposed MAC protocol consist the three parts (constructing hierarchy, scheduling and transmitting). In constructing hierarchy part, the protocol builds a tree. And the tree is divided to sub-tree. The scheduling part is divided two periods (request and confirm). In schedule request period, a node is transmitting the scheduling information to parent node in sub-tree. The scheduling information is aggregated with own and children's information. In scheduling confirm period, a node notify the data transmission time to child. In transmitting part, wake-up and send out the data in scheduled time. For evaluation, we simulate the proposing MAC protocol with SMAC. We shown that proposing MAC protocol provide the better performance with energy efficient and low latency. Scalability and adaptability is lower than SMAC. But scalability and adaptability is acceptable because nodes are not move frequently in target application.