Performance Analysis of MAC Energy-saving Strategies for WLANs

The IEEE 802.11 protocol has become the de facto communication technology for WLANs (Wireless Local Area Networks). While considered reliable and efficient for applications requiring high datarate, IEEE 802.11 is often disregarded for energy-sensitive applications such as IoT (Internet of Things). In fact, the IEEE 802.11 standard and its amendments have introduced several energy-saving mechanisms over the years that are rarely used in practice. In this paper, we consider seven possible energy-saving strategies for the MAC layer of IEEE 802.11. Using two case studies, we evaluate and compare these energy-saving strategies with regard to their network performance and energy saving. We conclude that most of the energy-saving strategies manage to support the levels of workloads considered in our case studies, and at the same time, they succeed to cut energy consumption by a factor ranging from two to eight. In particular, the "DL slot" strategy leads STAs to consume only half (or even less) of what they would without running any strategy, without trading off the attained levels of throughput. The "DL prompt + UL slot" strategy is the most efficient energy-wise, but this can come at the expense of a loss of throughput.