1. Appended Channel Switch Announcement
January 2007
doc.: IEEE /0078r0
January 2007
Appended Channel Switch Announcement
Date:
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Qi Wang, Broadcom Corporation
Qi Wang, Broadcom

2. January 2007
Problem Statement
A mechanism is needed to communicate Regulatory Class (RC) info. from AP to member STAs during a channel switch announcement (CSA)
In TGn 20/40 MHz BSS operation, the secondary channel offset info. is imbedded in the RC info.
RC is also used for defining other STA behavior (TX power, channel set, etc)
The policy on the allowed number of operating RC(es) shall be specified
Currently, this is no specification on this
Qi Wang, Broadcom Corporation

3. January 2007
Abstract
Propose a mechanism to include the Regulatory Class info. in the channel switch announcement
Propose a policy on the allowed number of Regulatory Class(es) in one BSS
Compare performance of this and alternative proposals
Qi Wang, Broadcom Corporation

4. January 2007
doc.: IEEE /0078r0
January 2007
Proposed Mechanism
Adopt a variable-length E-CSA IE which contains RC info.
Append the E-CSA IE to the existing CSA frame when needed
Explicitly specify the use of the CSA frame (modified or not) in all bands
Ensure proper channel switch of both legacy and new devices.
Qi Wang, Broadcom Corporation
Qi Wang, Broadcom

5. Alternative Proposal in 1775r1
January 2007
doc.: IEEE /0078r0
January 2007
Alternative Proposal in 1775r1
Adopt an fixed-length (6-octets) E-CSA IE which contains RC info.
Append the E-CSA IE to the existing CSA frame when needed
Define a new E-CSA frame in all bands
Legacy device may not be able to switch channel
Qi Wang, Broadcom Corporation
Qi Wang, Broadcom

6. Our vs. 1775r1 Proposal: New RC ≠ Current RC
January 2007
Our vs. 1775r1 Proposal: New RC ≠ Current RC
Qi Wang, Broadcom Corporation

7. Our vs. 1775r1 proposal: New RC = Current RC
January 2007
Our vs. 1775r1 proposal: New RC = Current RC
Qi Wang, Broadcom Corporation

8. January 2007
doc.: IEEE /0078r0
January 2007
Ours vs. 1775r1 Proposals
Our proposal enables STAs to switch to the new channel in all scenarios using ONE frame
1775r1 proposal
enables STAs to switch to the new channel in scenarios except one case on slide6
but this can be fixed via also sending the CSA frame
for legacy RC-unaware STAs, TWO frames (E-CSA+ CSA) are needed
For legacy RC-unaware STAs, correct RC switch is not guaranteed due to their lack of the concept of RC
The rules on the allowed number of RCs in one BSS need to be specified
Qi Wang, Broadcom Corporation
Qi Wang, Broadcom

9. Our Proposed Policy on Number of RC per BSS
January 2007
doc.: IEEE /0078r0
January 2007
Our Proposed Policy on Number of RC per BSS
Heterogeneous RCs per BSS is a reality
In BSS with RC-unaware AP, “one RC/BSS” is not enforceable
In BSS with RC-aware AP with new CSA capability, legacy RC unaware STAs shall not be banned by to obtain BSS membership
We propose:
One BSS = one of more RCs
AP association criteria w.r.t. RC depends on individual AP’s policy, and not specified in
Consequently, a channel switch announcement shall enable the correct channel switch at minimum and the correct RC switch if all possible
Qi Wang, Broadcom Corporation
Qi Wang, Broadcom

10. Conclusion We have proposed an efficient CSA mechanism to:
January 2007
Conclusion
We have proposed an efficient CSA mechanism to:
Ensure backwards compatibility and simultaneously enable new RC capability
Modify existing CSA frame; no new action frame is introduced.
We have proposed the policy on the allowance of one or more RCs in one BSS
We have proposed to clarify that how an AP uses RC info. in its association is the AP’s policy choice and not specified by
Qi Wang, Broadcom Corporation

11. References IEEE P802.11n/D1.07 draft IEEE P802.11-REVma/D9.0 draft
January 2007
References
IEEE P802.11n/D1.07 draft
IEEE P REVma/D9.0 draft
Qi Wang, Broadcom Corporation

12. January 2007
Motion
TGn draft shall include the text proposal in document /0077r0
Mover: Qi Wang
Seconder:
Result:
Qi Wang, Broadcom Corporation