A method is presented for increasing wireless LAN (WLAN) capacity in high-density environments with IEEE 802.11ax systems. We propose using coordinated scheduling of trigger frames based on our mobile cooperative control concept. High-density WLAN systems are managed by a management server, which gathers wireless environmental information from user equipment through cellular access. Hierarchical clustering of basic service sets is used to form synchronized clusters to reduce interference and increase throughput of high-density WLAN systems based on mobile cooperative control. This method increases uplink capacity by up to 19.4% and by up to 11.3% in total when WLAN access points are deployed close together. This control method is potentially effective for IEEE 802.11ax WLAN systems utilized as 5G mobile network components.

Efficient use of heterogeneous wireless access networks is necessary to maximize the capacity of the 5G mobile communications system. The wireless local area networks (WLANs) are considered to be one of the key wireless access networks because of the proliferation of WLAN-capable mobile devices. However, throughput starvation can occur due to the well-known exposed/hidden terminal problem in carrier sense multiple access with collision avoidance (CSMA/CA) based channel access mechanism, and this problem is a critical issue with wireless LAN systems. This paper proposes two novel schemes to identify starved access points (APs) and user equipments (UEs) which throughputs are relatively low. One scheme identifies starved APs by observing the transmission delay of beacon signals periodically transmitted by APs. The other identifies starved UEs by using the miscaptured beacon signals ratio at UEs. Numerous computer simulations verify that that the schemes can identify starved APs and UEs having quite low throughput and are superior to the conventional graph-based identification scheme. In addition, AP and UE management with the proposed schemes has the potential to improve system throughput and reduce the number of low throughput UEs.