QoS-Oriented OFDMA MAC Protocol for the Next Generation WLAN

With the increasingly diverse services and the explosively growing traffic, quality of services (QoS) guarantee is one of the most important goals of next generation wireless local area network (WLAN). Orthogonal frequency division multiple access (OFDMA) is an important feature of next generation WLAN. However, many existing studies focusing on the media access control protocol of the next generation WLAN neglect the guarantee of QoS and fairness. In this paper, we propose a QoS oriented OFDMA multiple access protocol for the next generation WLAN, named QoS-OFDMA. QoS-OFDMA introduces two times random access. The first random access does not distinguish the service priority, which guarantees the fairness. Meanwhile, the high-priority users failing to first random access are allowed to perform a second random access on the remaining available sub-channel. Thus, it improves the QoS of the high priority traffic. Simulation results show that compared with RA-OFDMA protocol and OMAX protocol, QoS-OFDMA high-priority service throughput outperform both by 22.05% and 89.6% respectively, and also guarantee the fairness requirement.