An Empirical Study of MAC Protocols for Wireless Sensor Networks and Design of Cognitive Radio Sensor networks

Wireless Sensor Networks (WSNs) has been an active research area for more than a decade. The range of applications has spanned beyond military domain to commercial domains. Typically, a WSN consists of spatially distributed autonomous sensors to monitor physical or environmental conditions. These sensors generate report over the network on the occurrence of any event. An efficient Medium Access Control (MAC) protocol holds a paramount importance for a WSN to provide better reliability and improved lifetime. Several multi-channel MAC protocols exist which perform better than the single channel protocols. The function of MAC layer is to coordinate transmission between the users sharing a spectrum and hence improves the throughput and energy efficiency. Cognitive Radio (CR) is an adaptive, intelligent radio and network technology which automatically detects the available channels in a wireless spectrum and make those channels available for concurrent transmissions. Dynamic spectrum access in the form of cognitive radio provides spectrum efficient communication for all WSNs which led to the development of Cognitive Radio Sensor Networks (CRSNs). This paper highlights an intensive study of some MAC protocols defined for WSNs and a brief description on the design of Cognitive Radio based WSNs. Keywords: Wireless Sensor Networks (WSNs), Medium Access Control (MAC), Cognitive Radio (CR)