High-efficiency WLANs for dense deployment scenarios

摘要

In this article, we review the latest technical attributes such as orthogonal frequency division multiple access (OFDMA), multi-user MIMO (MU-MIMO) and enhanced clear channel assessment (CCA) for better spatial reuse used in the 802.11ax amendment to the 802.11 standard that leads to PHY and MAC enhancements for high-density scenarios of access points (APs). IEEE 802.11ax, also referred to as high-efficiency wireless local area network (WLAN) (HEW), provides mechanisms to thoroughly utilize the unlicensed spectrum bands (2.4 and 5GHz) and strengthen the user experience. The functional requirements of HEW are stressed on interactive video transmission latency and access efficiency to meet quality of service (QoS) requirements. Finally, we investigate three configurationsMU-MIMO, OFDMA and combination of both or mixed modefor 4-user AP transmission schemes in 802.11ax. The performance of the MU schemes varies with packet size and operating SNR. OFDMA is more efficient than MU-MIMO at low SNRs for all packet sizes, which means 5th percentile stations (STAs) can get desired throughput.