Sequential transmissions for performance improvement of Sub-1 GHz WLANs

IEEE 802.11ah Task Group is developing a new wireless LAN technology that operates under 1 GHz band and supports more than 8,000 stations. Due to the large number of stations, RAW (Restricted Access Window) mechanism is adopted in order to alleviate the increased collision probability. However, as the time slots of RAW are allocated without any consideration of traffic load, the medium resource might be inefficiently used. In addition, stations belonging to a same group have to contend for channel, and thus severe collisions may occur in a large group of stations. In this paper, we propose a sequential transmission scheme, which provides an efficient way of source management in the Sub-1 GHz WLANs by considering the traffic loads and allocated channel access times of the stations. Using discrete simulations, we prove that our proposed protocol can enhance the performance of the WLANs.