<title>Managing heterogeneous wireless environments via Hotspot servers</title>

Abstract

Wireless communication today supports heterogeneous wireless devices with a number of different wireless network interfaces (WNICs). A large fraction of communication is infrastructure based, so the wireless access points and hotspot servers have become more ubiquitous. Battery lifetime is still a critical issue, with WNICs typically consuming a large fraction of the overall power budget in a mobile device. In this work we present a new technique for managing power consumption and QoS in diverse wireless environments using Hotspot servers. We introduce a resource manager module at both Hotspot server and the client. Resource manager schedules communication bursts between it and each client. The schedulers decide what WNIC to employ for communication, when to communicate data and how to minimize power dissipation while maintaining an acceptable QoS based on the application needs. We present two new scheduling policies derived from well known earliest deadline first (EDF) and rate monotonic (RM) [26] algorithms. The resource manager and the schedulers have been implemented in the HP's Hotspot server [14]. Our measurement and simulation results show a significant improvement in power dissipation and QoS of Bluetooth and 802. 1 lb for applications such as MP3, MPEG4, WWW, and email.

Context-for-wireless

“…Coolspots [20] employs Bluetooth to improve power efficiency of Wi-Fi. Nevertheless, these works and others [11,21,26] target at improving Wi-Fi energy efficiency and are restricted by limited Wi-Fi availability. On the contrary, our approach utilizes Wi-Fi to improve the efficiency of cellular networks and provide energy-efficient ubiquitous connectivity.…”

SwitchR: Reducing system power consumption in a multi-client, multi-radio environment

“…However, the authors do not present any evaluation of the benefits of such a scheme. Another technique is to use application level hints to decide which wireless interface would be most energy efficient for active data transfer [14] [17]. The authors unfortunately do not provide much detail in terms of their evaluation and experimental setup; [17] in fact reports a 10% increase in power consumption for a benchmark emulating web traffic.…”

Power Saving Techniques for Wireless LANs

“…A number of scheduling algorithms have been implemented in the Hotspot's [ [3]] resource manager, ranging from standard real-time schedulers such as earliest deadline first, to well known packet level schedulers such as weighted fair queuing [ [4]]. Figure 2 summarizes the average power measured for three concurrent IPAQ 3970 clients receiving high-quality MP3 audio first through standard WLAN and Bluetooth interfaces with no additional scheduling, and then with Hotspot scheduling.…”