Delay-Aware Device Grouping in IEEE 802.11ah-Based Networks.

With the flourishment of Internet-of-Things (IoT), wireless systems are expected to serve a massive number of IoT devices (IoTDs) with diverse service requirements. Wi-Fi Alliance introduced IEEE 802.11ah for IoT applications. The restricted access window (RAW) mechanism in IEEE 802.11ah can alleviate congestion due to a huge number of simultaneous access requests. IEEE 802.11ah adopts the uniform device grouping method, which uniformly assigns IoTDs to slots in one RAW. However, in one RAW group with both delay-tolerant devices (DTDs) and delay-sensitive devices (DSDs), the performance of delay-sensitive devices (DSDs) will be severely affected by DTDs. In this paper, a delay-aware device grouping method for RAW (DADG-RAW), which allocated dedicated slots for DSDs, was suggested to improve the performance of DSDs. Simulation results demonstrated that the proposed approach could improve the performance of DSDs in terms of throughput, delay, and satisfaction ratio when compared to the traditional RAW.