Energy effective Standby mode for Home Femto Access Point: solutions to a radical twist of the mobile networking paradigm
20 October 2009
Recent European directives [2] require to include eco-designed off-mode or standby-mode in the household and office equipment. By the end of 2012, the equipments will have to automatically switch to off/stand-by mode after a short period of inactivity. Furthermore, the energy consumption limits of those lowpower modes are set to be challenging, requiring 1 watt by end 2009 for off/stand-by mode without display, and 0.5 Watt by end 2012. The Home Femto Access Points, whatever their Radio Access Technology UMTS, LTE, Wimax or Wi-Fi, are not ready for the incoming regulation. Each consumes around 10 Watts when fully loaded and 6 Watts when unloaded. As they are deployed by millions, they draw a large power. We firstly state the motivations to develop an energy efficient standby mode. Then we describe this mode and the challenges and constraints that have to be taken into account when designing it. Then technical implementation solutions are presented, in particular on the way to wake-up a Home Femto Access Points in standby mode. Lastly, we present the prototype of a Wi-Fi Access Points enhanced with a low-consumption standby system and we report and analyse the results obtained. (head 1) Motivations and drivers for an energy efficient standby mode The 10 years old One Watt Initiative [1] from the International Energy Agency aims at reducing the standby power used in all appliances to one watt and proposes many appliance modes that might be considered in the definition of standby power [4].