수중 무선통신 환경에서의 무작위 전송에 의한 영향 분석

Abstract

It is very difficult to directly apply general terrestrial MAC protocols to underwater acoustic communication network because of very slow propagation velocity(1,500 m/s) of the acoustic waves and very low data rate(several kbps). Many research on the MAC protocols of underwater acoustic network are studied for underwater mobile network which are consist of AUV(Autonomous Underwater Vehicle), Submarines, divers, mother ship and fixed oceanographic instrument or sensor nodes. Recently, the active research of a channel competition MAC protocols like as CSMA/CD(Carrier Sence Multiple Access with Collision Detection) and CSMA/CA(CSMA with Collision Avoidance) are progressed in underwater acoustic network without communication infra. These protocols basically use the control packet such as RTS/CTS/ACK for an stable allocation of a wireless communication channel and random back-off mechanism before the data transmission for preventing a collision by simultaneous transmission. This paper shows these control packets and back-off mechanism induce degradation of network performance(throughput and delay) because of slow propagation delay and low data rate in underwater acoustic environment, and simple random transmission without control packets and back-off mechanism give preferable network performance through the implemented simulator program.