OPNET-based Simulation And Research On MAC Protocol Of Data Link Layer In Underwater Acoustic Networks

As an important composition of the global stereo information networks, underwater acoustic networks (UAN) has been a hot research topic in the last ten years. UAN is constructed not only for long term ocean monitoring, but for real-time data communication. Through the surface buoy, the UAN can switch information with the work station on the shore and even with high-speed global internet. UAN can serve for auxiliary navigation, disaster prevention, seism and tsunami forecast, resource exploitation and national defense.The point to point communication between two underwater nodes can be implemented by acoustic modem couple. However, the construction of UAN is extreme difficult especially on the aspect of the share of the channel resource due to the severe limitation of the channel band, the limited energy supply and the low and inconstant propagation speed of acoustic signal which lead to long propagation delay.This paper mainly focuses on the media access control (MAC) protocol, which is the part of the data link layer and manages the share of channel resource among the nodes in the UAN. The common MAC protocols like ALOHA, MACAW ,DBTMA in traditional ad hoc network is applied in the UAN, the simulation results is given which demonstrate the performance of energy consumption, network throughput, average delay and successful packet-sending ratio. For the purpose of meeting the special demands of energy saving in UAN, the MACAW protocol is optimized by employ the concept of sleep mode and transmission power control. The further simulation result is also presented.