Research on MAC Protocols for Wireless Sensor Networks

Wireless Sensor Networks (WSNs) have been widely used in many fields recently,such as environmental monitoring, intelligent transportation system, industrial automationand medical monitoring. The MAC layer, as a key component of Wireless SensorNetworks, plays a critical role in the performance of entire networks. In this paper, ourstudy mainly includes the following contents.First, we propose a nevel reservation based MAC protocol for Underwater WSNs. Inthis protocol, the source node and destination node can receive data packets from theirown one-hop neighbours without collisions after they initialize a handshake and finishtheir transmission. This protocol can make full use of characteristics of underwateracoustic channels, and adopts a concurrent reservation mechanism to avoid collisions,resulting in high channel utilization. Simulation results have confirmed that the proposedprotocol can offer better performance on throughput and delay in multi-hop UnderwaterWSNs.Second, we have performed some experiments with testbeds for the interferencebetween WSNs and Wireless Local Area Networks (WLAN) when they share the same2.4GHz ISM band. Results show that the interference on WSNs brought by WLAN can befallen into two types according to their distances: symmetric and asymmetric interference.Then, we integrate different anti-interference methods into the802.15.4based MACprotocol, namely, modifications of MAC packets and error control coding. Finally, wehave implemented these anti-interference methods with TinyOS to confirm the goodperformance.