arrow
Return

Lock Step: An Algorithm to Reduce Wi-Fi Jitter

delete2009-07-01
delete2
PRE
AI
H
Hong Lin *
D
David McDonald
DOI:10.1109/LCOMM.2009.090999delete
deleteOriginal
deleteOriginal request for help
deleteShare
deleteSave
Abstract

Abstract

En 中文
The exponential backoff algorithm used in IEEE 802.11 does not guarantee short term fairness between flows. We propose an algorithm based on IdleSense where each of N flows tries to transmit every W = 8N slots; i.e. 8 slots per flow with 7 idle. Each flow adaptively adjusts its contention window W based on the observed proportion of empty slots. One key aspect of Lock Step is setting a deterministic backoff after a successful transmission so that, for persistent flows, eventually all users are in lock step and transmit every 8N slots. Another key aspect is forcing a second collision between colliding users so all users can better estimate the proportion of idle slots per transmission thus allowing users to estimate N and hence the optimal backoff. This second collision can also be engineered to assist the ZigZag algorithm to decode the colliding packets. Even with transient flows Lock Step reduces jitter and can substantially increase the number of flows carrying Voice over IP traffic through a single access point.
Keywords:
IEEE 802.11
Wi-Fi
AC
Idle Sense
DCF

Journal

IEEE Communications Letters cover
IEEE Communications Letters
IF:
4.4
Papers:
1.3W
Citations:
2.2W

Organization

U
University of Ottawa
Scholars:
3.5W
Papers: 3.1W
Citations: 3.8W