A Review towards HoWiEs: Zigbee Assisting WiFi for Reducing Energy

This paper is a step towards HoWiEs, a system that saves Energy, consumed by WiFi interfaces in mobile devices with the assistance of Zigbee radios in mobile devices. The WiFi radio power consumptions is significant nowadays in mobile devices and other. Existing measurements showed that the power consumptions of WiFi scanning and PSM standby in a Samsung Galaxy S2 smartphone accounted for 65% and 11% of the entire system power consumption respectively, and recent works showed that the wakeup contentions could cause up to four times more power consumption. There are three scenarios where a WiFi radio has to stay active without performing any real communications. First, a WiFi radio must be continuously active to scan for networks in the scanning state. The power consumption is low for network scanning when WiFi coverage may not be available. Second, during PSM (Power Save Mode) standby, a WiFi radio needs continuously active to receive wireless access point (AP) beacons, and check if the AP has buffered its packets. Long WiFi leads in power reduction even during PSM standby. Third, when waken up from PSM standby, a WiFi radio has to active while waiting period for its turn to communicate with the AP if there are multiple devices contending for the channel. Study, related to WiFi power reduction and related work shows effective results. Related work optimizing concepts ZiFi, Wake On Wireless, ipoint, E-MiLi etc.