Efficient and reliable multicast over a Wi-Fi network

US8411608B2 · kind B2 · utility

Assignee

• Microsoft Corporation · US

Inventors

• Ranveer Chandra · Kirkland, US
• Sandeep P. Karanth · Bengaluru, IN
• Thomas Moscibroda · Beijing, CN
• Vishnu Navda · Bengaluru, IN
• Jitendra D. Padhye · Redmond, US
• Ramachandran Ramjee · Summit, US
• Lenin Ravindranath Sivalingam · Cambridge, US

Key dates

• Filing date: Feb 26, 2010
• Grant date: Apr 2, 2013
• Expiry date: Apr 16, 2031

Classification

• Technology area (CPC H): Electricity
• CPC primary: H04W48/20
• WIPO field: Digital communication
• WIPO sector: Electrical engineering

Abstract

A “Wi-Fi Multicaster” provides a practical and efficient Wi-Fi multicast system for environments having potentially large numbers of Wi-Fi clients. Significantly, the Wi-Fi Multicaster does not require any changes to the 802.11 protocol, or to the underlying Wi-Fi infrastructure. In various embodiments, the Wi-Fi Multicaster uses pseudo-broadcast, and augments it with destination control, association control and optional proactive FEC (forward error correction) to improve multicast performance. More specifically, the Wi-Fi Multicaster system converts multicast packets to targeted unicast transmissions. To minimize the amount of airtime consumed, the Wi-Fi Multicaster uses destination control in combination with various algorithms for association control. Further, in various embodiments, the Wi-Fi Multicaster includes an adaptive, proactive FEC scheme to reduce overall packet losses. Finally, to overcome the challenges posed by encryption protocols such as 802.1x, the Wi-Fi Multicaster uses a “virtual multicast interface” that allows clients to “share” a common key for each multicast.