Softspeak
Welcome to the Softspeak project!
In this project we aim to
make VoIP (Voice over IP) and WiFi (802.11) co-exist peacefully.
We've developed a system that can do this using existing WiFi hardware and
access points.
What's the basic problem we're addressing?
By default,
VoIP traffic is wasteful of WiFi airtime in the following ways. First, VoIP
traffic consists of tightly spaced small packets, each of which is encumbered with
large 802.11 and other headers. Second,
when the channel gets busy, packets from multiple VoIP senders are
increasingly likely to
collide, rendering some or all of the packets indecipherable to the access point. These issues translate to
a lot less bandwidth for other traffic (such as Web traffic) as well as
degraded call quality. Softspeak addresses the problem by (a)
aggregating many small packets into a few large packets, (b) imposing a TDMA
schedule to avoid collisions.
The details are in our NSDI 2009 paper.
We have implemented Softspeak on Linux for the Ralink and Madwifi WiFi
chipsets and made recordings of voice traffic before and after
applying Softspeak:
Publications
Softspeak: Making VoIP Play Well in Existing 802.11 Deployment
[pdf]
[html]
P. Verkaik, Y. Agarwal, R. Gupta, A. C. Snoeren
Proceedings
of the 6th ACM/USENIX Symposium on Networked Systems Design
and Implementation (NSDI), Boston, MA, April 2009.
Slides:
[ppt]
[pdf]
How to avoid killing the wireless internet with your phone
[pdf]
[ppt]
P. Verkaik, Y. Agarwal, A. C. Snoeren
Poster for Jacobs School of Engineering Research Expo, 2008.
Project members
This project is part of the
Systems and Networking
Wireless Research Group at UCSD.