1. Beacon Compression Month 2000 doc.: 11-03-0684-r0-k September 2003
Martin Lefkowitz,
Malik Audeh,
Trapeze Networks,
5753 W. Las Positas Blvd.,
Pleasanton, CA 94588
Martin Lefkowitz
Martin Lefkowitz, Trapeze Networks

2. What is Beacon Compression?
September 2003
What is Beacon Compression?
Beacon Compression leverages the idea that there is a lot of information that is unnecessarily repeated in the beacon. Once this information is seen by the STA, it can be “compressed,” and only the dynamically changing information is needed to make a roaming decision.
Beacon Compression is a collection of measurement tools that can be used by a STA to gain information quickly about the operating environment.
Beacons are used in a similar way as link in that it is a medium sensing tool that is the building block to creating a connection (association) with the network.
Beacon Compression can also be used to eliminate the need for constant probing required to maintain a good connection.
Martin Lefkowitz

3. Beacon Compression Features
Month 2000
doc.: r0-k
September 2003
Beacon Compression Features
Beacon Compression takes advantage of the fact that there is a lot of information that changes very infrequently in the Beacon.
Beacon Compression can allow fast access to needed dynamic information.
Beacon Compression can also allow the scheduling of the passive reception of beacons.
Martin Lefkowitz
Martin Lefkowitz, Trapeze Networks

4. September 2003
Beacon Compression
STA’s make use of various passive and active mechanisms to receive the dynamic information about the BSS and BSA.
To Schedule reception of full Beacon, if necessary.
To make the determination that transmitting on the channel is allowed.
First step in performing a probe request when h or d are in operation.
To know if it’s worth going through a full probe request procedure for a particular BSS.
To make it’s roaming decision.
Martin Lefkowitz

5. Beacon Components in Regards to Roaming
Month 2000
doc.: r0-k
September 2003
Beacon Components in Regards to Roaming
Components of a beacon that remain static
SSID
Supported Rates
Beacon Interval
Channel
Capability
Country (802.11d)
Security (802.11i)
Transmit Power (802.11h)
Components of a Beacon that are dynamic
RSSI
Load (802.11e)
Channel Switch(DFS/802.11h)
Channel Quiet(802.11h)
Martin Lefkowitz
Martin Lefkowitz, Trapeze Networks

6. Beacon Compression Components
September 2003
Beacon Compression Components
Site Report/channel map
Domain Signaling
Sending information about the BSS/BSA
Without sending a beacon
Without disrupting traffic
Directed Probe Request with “No Response” option.
Receive Signal Strength information in a SIFS
Modification to existing Standards/TGk Draft to enable Beacon Compression
Add TBTT Offset to Site Report to allow scheduling of beacon reception.
If you already know the country, and know Spectrum management is required, and have already received enough beacons to understand; security issues, capabilities, country, etc, then;
All you need is to match the source address of any packet with the BSSID of interest from the site report to understand.
Signal Strength
Spectrum and country specific information.
Or you can camp on the channel long enough to receive the Domain Signal Packet.
Martin Lefkowitz

7. Beacon Compression Components
Month 2000
doc.: r0-k
September 2003
Beacon Compression Components
Are presented in the following documents;
k-Directed-Probe-Request-With-No-Response-Option.ppt
k-domain-signaling.ppt
k-Neighbor TBTT Offset
k-Targeting-Potential-Roam-Candidates.ppt
Martin Lefkowitz
Martin Lefkowitz, Trapeze Networks

8. September 2003
Conclusion
The components of Beacon Compression can be used in a number of ways to facilitate both fast scanning as well as minimizing the amount of time currently required for passive scanning by knowing the beacon schedules of neighbors.
By making Passive Scanning feasible Beacon Compression can help reduce total STA power requirements.
By reducing the time required to perform a scan Beacon Compression can facilitate ascertaining important dynamic information needed for a roaming decision.
While actively sending data.
Constantly in the background to make a better roaming decision.
Reduces effect of large dynamic multipath fades.
Martin Lefkowitz