Full Duplex 통신에서의 HIDDEN POLLING 기법

Abstract

In the half duplex transmission systemwhich is widely used onthe WLAN, each station can transmit or receive packets separately in a single band.However in the full duplex transmission system, each station can transmit and receive packets simultaneously in a single band. Therefore on the WLAN, full duplex transmission can increase throughput owing to simultaneous UL/DL transmissions. However in real world, DL packet size is much larger than UL packet size and due to difference of packet size, UL stations lose transmission opportunity. Because, during the DL transmission all UL stations detect that the medium is in busy state and they just wait until the medium becomes idle. Therefore difference of packet size degrades efficiency of full duplex communication and each station`s throughput gain. In this paper, I propose hidden polling scheme. In this scheme, I defined Full duplex RTS (FRTS) to identify hidden stations and notify hidden polling order. Each station can recognizeits hidden stations using FRTS/CTS and inform hidden station address to AP using FRTS. AP uses hidden information to report polling order of DL receiver`s hidden stations through hidden list field in FRTS. Then AP transmits polling signal through control subcarrier to start next UL transmission whenever previous UL transmission is over. Simulation result showed that our proposed scheme increased UL throughput compared to full duplex system in a single band