A Simple Backoff Scheme for Full Duplex MAC protocols in Wireless LANs

Abstract

For achieving the benefits of full duplex (FD) communications in wireless local area networks (WLANs), it is important to design the medium access control (MAC) protocols for FD communications. As the particular function of full duplex MAC (FD-MAC) protocols, each node transmits a data frame even if its backoff timer is not zero when it is an FD transmitter. Additionally, the backoff scheme in the FD-MAC protocols is following the conventional scheme based on the distributed coordination function. Therefore, the nodes with FD-MAC initialize the contention window (CW) size after their successful FD transmissions. However, the initialization and the particular operation in the FD-MAC cause further frame collisions at stations (STAs), leading to the degradation the network throughput. This paper proposes a simple backoff scheme for FD-MAC protocols. In the proposed scheme, the CW size and backoff timer are not initialized and keep the current value after FD transmissions. The proposed scheme can mitigate frame collisions at STAs and increase FD-transmission opportunities. Although the proposed scheme requires the small change from the conventional one, it can enhance the throughput significantly. The simulation results show the effectiveness of the proposed scheme.