Achilles and the Tortoise: Power consumption in IEEE 802.11n and IEEE 802.11g networks

Cloud computing is currently emerging as the de facto standard for Internet service provisioning. This uptake is motivated, among other aspects, by the significant reduction in energy consumption that can be achieved by centralizing, consolidating and optimizing large IT infrastructures. At the same time, however, users expect to access cloud services via wireless access networks using smartphones and tablets. Several studies already show that wireless technologies such as WiFi and 4G are becoming the dominant access to cloud services. However, while energy efficiency is accounted for the end-user devices and data-centers, the actual energy consumption of wireless access networks is typically overlooked, even though it is expected to account for about 90 % of the entire wireless cloud energy footprint. In this paper, we use real-world measurements to present a complete analysis of the power consumption and performance of IEEE 802.11n. We also compare IEEE 802.11n with its predecessor, the widely deployed IEEE 802.11g standard, and confirm that 802.11n (2×2 MIMO) performs ~ 4.5 times better than 802.11g in terms of maximum network throughput as expected while at the same time reducing the required energy per bit by ~ 50%.