Enhancing IEEE 802.11ah Networks: A Spatial Multi-Channel MAC Protocol

Abstract

IEEE 802.11ah is designed to enhance IoT networks by supporting numerous stations, extending coverage range, reducing power consumption, and operating within the sub-1 GHz band. The Restricted Access Window is introduced to mitigate collisions and improve network throughput when multiple stations contend for the channel simultaneously. While the PHY layer in IEEE 802.11ah supports multiple channels with different bandwidths, the MAC layer only supports a single channel for communication between the Access Point (AP) and stations. However, network performance can be improved by enabling stations at different locations to exchange data packets on different channels concurrently. This paper proposes a Spatial Multi-channel MAC (SM-MAC) protocol for IEEE 802.11ah, which divides the AP’s coverage area into sectors, each assigned a dedicated channel. Each sector is served by two Forwarders responsible for relaying data packets between stations and the AP. The performance of the SM-MAC protocol is evaluated against the IEEE 802.11ah MAC protocol in terms of packet delivery ratio, throughput, and energy efficiency.