Power aware network interface management for streaming multimedia

A significant fraction of the power in portable devices (handheld terminals, PDAs, laptops, etc.) is drawn by the wireless network interface card (NIC). We test the viability of a novel power management technique, based on the exploitation of the NIC off-mode while a client-controlled streaming multimedia application is in progress. The basic idea is to switch off the card while frames are being played back, until a low-threshold level is reached in the client buffer. In this paper, pessimistic assumptions are made on the timing and power overheads associated with recovering the card from off-mode, but nevertheless a power saving of about 25% is achieved over the average power consumption incurred by the standard IEEE 802.11 mechanism. We also provide design curves showing the minimum buffer size that makes our technique effective, as a function of the network bandwidth and of the card characteristics.