1. Managed BSS Channel Switch
January 2003
IEEE /100r1
Managed BSS Channel Switch
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Kwak, Rudolf, InterDigital
Submission

2. Kwak, Rudolf, InterDigital
Outline
Introduction
TGh features for Channel Switch
New TGv features for Channel Switch
Protocol message sequence
Frame contents
Conclusions
Kwak, Rudolf, InterDigital
Submission

3. Kwak, Rudolf, InterDigital
January 2003
IEEE /100r1
Introduction
Interference and radar avoidance are motivators.
Interference environments different for each STA is BSS.
Measurements from all STAs on serving channel and alternate channels are relevant.
STAs and network/AP may have different priorities in selecting alternate channel.
Protocol described here is compatible with distributed and central control approaches.
Complete normative text found in 05/1084r0.
SMI – Structure of Management Information
ASN.1 – Abstract Syntax Notation 1
Kwak, Rudolf, InterDigital
Submission

4. TGh Features for Dynamic Frequency Selection (DFS) for Radar Avoidance
Basic Request/Response collects info for radar sensing/detection (details unspecified).
AP may use proprietary radar detection technique or may have a-priori radar knowledge.
AP decides unilaterally on need for switch to avoid radar and time to switch.
Channel Switch Announcement in beacon signals synchronized BSS channel switch
Kwak, Rudolf, InterDigital
Submission

5. New TGv Features built upon TGh functions
Protocol permits AP/STA negotiation
Any STA may initiate protocol when needed (optional)
AP may poll all STAs for individual preferences (optional)
AP decides to relocate BSS, selects channel and time for BSS switch
AP may signal decision using TGh Channel Switch Announcement
Each STA decides to follow BSS or to roam
Each STA confirms operation in BSS on new channel.
Protocol may be used to enhance TGh DFS to make better selection of new channel
Kwak, Rudolf, InterDigital
Submission

6. Message Sequence for BSS Channel Switch
January 2003
IEEE /100r1
Message Sequence for BSS Channel Switch
Other
STAs AP
STAx
Channel Switch Solicitation
Channel Switch Request[Query]
Channel Switch Reports [Query]
AP decides to switch and selects: new channel, switch time, response time
Channel Switch Announcement
Channel Switch Announcement
Channel Switch Announcement
Channel Switch Request[Confirm]
SMI – Structure of Management Information
ASN.1 – Abstract Syntax Notation 1
Switch Time
Channel Switch Announcement
Channel Switch
Response Time
Channel Switch Report(s)[did switch]
Required elements in italics, others optional
Kwak, Rudolf, InterDigital
Submission

7. Channel Switch Solicitation
Target
Channel
Number
Regulatory
Class
Channel Switch
Count
Response Time
Octets: 1
Sent by STA to suggest to AP that a channel switch is needed. (optional)
Usually based on degrading local conditions
Contains:
Channel spec, as usual
Suggested time for switch
Latest time for AP to reply, usually well before the suggested switch time.
Kwak, Rudolf, InterDigital
Submission

8. Channel Switch Request
Target Channel
Regulatory
Channel
Channel
Response Time
Response
Number
Class
Switch
Switch Count
Count
Randomization
Request Type
Interval 1 1 1 1 1 2
Sent by AP to STA(s) to query conditions at STA locations for possible channel switch, or to command a BSS channel switch
Query request permits negotiation of selected channel with STAs
Contains:
Channel spec, same as TGk
Request Type = Query (negotiation) or Confirmed (execution)
Switch count counts down to intended channel switch time
Response time counts down to latest time for STA to reply
Randomization to spread replies when broadcast
Kwak, Rudolf, InterDigital
Submission

9. Kwak, Rudolf, InterDigital
Channel Switch Report
Sent by STA in response to Channel Switch request
May contain alternate channel suggestion based on STA local conditions.
Contains:
Channel spec, as usual
Response code which is a function of the request type
Kwak, Rudolf, InterDigital
Submission

10. Channel Switch Response Codes
Response Definition for
Query Request Type
Confirmation Request Type
Reporting STA will not switch to
the requested channel.
not allowed 1
Reporting STA is able to switch
to the requested channel at the
requested time and will do so
when this channel switch request
is confirmed or when a this
channel switch is announced.
Reporting STA has switched to
the requested channel at the
requested channel switch time.
This response is sent as the first
transmission on the requested
channel after the requested
switch time. 2
Reporting STA will not follow, but
would follow on the Alternative
Channel Number.
not allowed. 3
requested time and may do so if
this channel switch request is
confirmed or when a this channel
switch is announced.
4-255
reserved
Kwak, Rudolf, InterDigital
Submission

11. Message Sequence for BSS Channel Switch
January 2003
IEEE /100r1
Message Sequence for BSS Channel Switch
Other
STAs AP
STAx
Channel Switch Solicitation
Channel Switch Request[Query]
Channel Switch Reports [Query]
AP decides to switch and selects: new channel, switch time, response time
Channel Switch Announcement
Channel Switch Announcement
Channel Switch Announcement
Channel Switch Request[Confirm]
SMI – Structure of Management Information
ASN.1 – Abstract Syntax Notation 1
Switch Time
Channel Switch Announcement
Channel Switch
Response Time
Channel Switch Report(s)[did switch]
Required elements in italics, others optional
Kwak, Rudolf, InterDigital
Submission

12. Kwak, Rudolf, InterDigital
Conclusions
Protocol and frames defined to permit negotiation of new channel and switch time
Compatible and builds on existing TGh capability
Useful for distributed and central control approaches
Similar to load balancing protocol (05/1064) with use of query/confirm request types
Kwak, Rudolf, InterDigital
Submission

13. Vote for Inclusion into TGv Draft
Move to instruct the editor to include normative text for Managed BSS Channel Switch in 05/1084r0 into next version of TGv Draft.
Moved by Joe Kwak
Seconded __________
YES_______
No________
Abstain _____
Kwak, Rudolf, InterDigital
Submission