Asym-FDMAC: In-band full-duplex medium access control protocol for asymmetric traffic in wireless LAN

Abstract

Recent advancements in antenna design and signal processing have made it feasible to transmit and receive simultaneously by using the same carrier frequency, which is defined as in-band full-duplex (IBFD) wireless communications. Along with physical layer advancements, efficient medium access control (MAC) design is required to derive optimal benefit from this latest technology. In this paper, an IBFD MAC protocol named Asym-FDMAC, is proposed for infrastructure based WLAN to support asymmetric lengths of traffic for uplink and downlink. This MAC protocol enables multiple users to transmit data to the access point (AP) during the transmission of a single downlink frame from the AP. In Asym-FDMAC, the AP always initiates the transmission. Therefore, there is no contention period and thus, there is no collision among the user terminals and the AP for channel access. A mathematical analysis of Asym-FDMAC is presented together with an evaluation of its performance, which involved a comparison with traditional IBFD and half-duplex (HD) communications. On average, the highest throughput gain achieved by Asym-FDMAC was approximately 54% and 94% compared with traditional IBFD and HD communications respectively, although the lowest average throughput gain was observed as about 50% and 89%, respectively.