IP based telephony is rapidly gaining acceptance over traditional means of voice communication. Wireless LANs are also becoming ubiquitous due to their inherent ease of deployment and decreasing costs. In enterprise Wi-Fi environments, VoIP is a compelling application for devices such as smartphones with multiple wireless interfaces. However, the high energy consumption of Wi-Fi interfaces, especially when a device is idle, presents a significant barrier to the widespread adoption of VoIP over Wi-Fi. Cell2Notify is a practical and deployable energy management architecture that addresses this issue by leveraging the cellular radio on a smartphone to implement wakeups for the high-energy consumption Wi-Fi radio. More generally, Cell2Notify provides a mechanism to send notifications to phones using the caller ID of an incoming call.

• Wireless Wakeups Revisited: Energy Management for VoIP Over Wi-Fi Smartphones
  Yuvraj Agarwal, Ranveer Chandra, Alec Wolman, Paramvir Bahl, Kevin Chin, Rajesh Gupta.
  Proceedings of ACM/USENIX MobiSys, Puerto Rico, June 11-14, 2007
  PowerPoint Presentation



• Cell2Notify: Energy Efficient VoIP for Wi-Fi Enabled Smartphones
  Yuvraj Agarwal, Ranveer Chandra, Alec Wolman, Paramvir Bahl, Kevin Chin.
  MSR TechFest Poster (March 2007)

• The Cell2Notify project is a joint collaboration between the Networking Research Group at Microsoft Research, Redmond and the MED Group at Microsoft.