1. doc: IEEE 802.11-06/0388r0March 2006 Submission Kwak, Rudolf, InterDigital 1 BSS Channel Switch Notice: This document has been prepared to assist IEEE 802.11. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor grants a free, irrevocable license to the IEEE to incorporate material contained in this contribution, and any modifications thereof, in the creation of an IEEE Standards publication; to copyright in the IEEE’s name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEE’s sole discretion to permit others to reproduce in whole or in part the resulting IEEE Standards publication. The contributor also acknowledges and accepts that this contribution may be made public by IEEE 802.11. Patent Policy and Procedures: The contributor is familiar with the IEEE 802 Patent Policy and Procedures, including the statement "IEEE standards may include the known use of patent(s), including patent applications, provided the IEEE receives assurance from the patent holder or applicant with respect to patents essential for compliance with both mandatory and optional portions of the standard." Early disclosure to the Working Group of patent information that might be relevant to the standard is essential to reduce the possibility for delays in the development process and increase the likelihood that the draft publication will be approved for publication. Please notify the Chair as early as possible, in written or electronic form, if patented technology (or technology under patent application) might be incorporated into a draft standard being developed within the IEEE 802.11 Working Group. If you have questions, contact the IEEE Patent Committee Administrator at.http:// ieee802.org/guides/bylaws/sb-bylaws.pdfstuart.kerry@philips.compatcom@ieee.org 2006-MAR-07

2. doc: IEEE 802.11-06/0388r0March 2006 Submission Kwak, Rudolf, InterDigital 2 Introduction BSS Channel Switch proposal: a simple solution addressing TGv objective #2000, Dynamic Channel Selection: “ TGv shall support Dynamic Channel Selection, to allow STAs to avoid interference. Solution shall be able to change the operating channel (and/or band) for the entire BSS during live system operation and be done seamlessly with no intermittent loss of connectivity from the perspective of an associated STA. Solution shall not define algorithm for channel selection. ” Normative Text in 11-06-0387-00-000v

3. doc: IEEE 802.11-06/0388r0March 2006 Submission Kwak, Rudolf, InterDigital 3 TGh falls short for BSS channel Switch TGh for Dynamic Frequency Selection for Radar Avoidance: AP decides on need for BSS switch, target channel, scheduled switch time. Switch Announcement in beacon signals synchronized channel switch Each STA decides to switch to target channel or to roam BSS startup on new channel is unspecified Only works in 5GHz band New TGv Features built upon TGh functions Any STA may (option) initiate BSS procedure when needed STA interference detection -->requested switch (like TGn BW change) Procedure permits AP/STA negotiation on target channel and switch time AP may poll all STAs for individual preferences (optional) AP may send unicast Channel Switch Requests for confirmed operation Short STA Response confirms operation in BSS on new channel Permits seamless, coordinated switch without reassociation overhead. Works for 2.4GHz and 5GHz bands.

4. doc: IEEE 802.11-06/0388r0March 2006 Submission Kwak, Rudolf, InterDigital 4 Simple Implementation Standard Request/Response exchange Optional Solicitation for STA initiation Unicast/broadcast signaling frames Randomization to avoid storm after switch Uses TGh broadcast Switch Announcement Works for 2.4 GHz and 5GHz

5. doc: IEEE 802.11-06/0388r0March 2006 Submission Kwak, Rudolf, InterDigital 5 Normative Text Review: 06/0393 Changes since last rev 05/1085 (JAN06): Stripped out framework elements Formatted messages as new frames Added MLME primitives Simplified Procedure text Added PICS elements Walkthrough Normative Text Document: 11-06-0387-00-000v-Normative_Text_BSS_Channel_Switch.doc

6. doc: IEEE 802.11-06/0388r0March 2006 Submission Kwak, Rudolf, InterDigital 6 Conclusions TGh is not adequate to meet TGv DCS Objective #2000 New procedure compatible with and builds on existing TGh capability Simple implementation Provides seamless BSS channel switch in both 2.4 GHz and 5GHz bands Questions & Discussion

7. doc: IEEE 802.11-06/0388r0March 2006 Submission Kwak, Rudolf, InterDigital 7 Vote for Inclusion into TGv Draft Move to instruct the editor to include normative text for BSS Channel Switch in 06/0387r0 into next version of TGv Draft. Moved by Joe Kwak Seconded __________ YES________ No________ Abstain ________

8. doc: IEEE 802.11-06/0388r0March 2006 Submission Kwak, Rudolf, InterDigital 8 BACKUP SLIDES FOLLOW These charts are provided for your further information

9. doc: IEEE 802.11-06/0388r0March 2006 Submission Kwak, Rudolf, InterDigital 9 Channel Switch Solicitation 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. Target Channel Number Regulatory Class Channel Switch Count Response Time Count Octets: 1 1 11 1

10. doc: IEEE 802.11-06/0388r0March 2006 Submission Kwak, Rudolf, InterDigital 10 Channel Switch Request Target Channel Number Regulatory Class Channel Switch Request Type Channel Switch Count Response Time Count Response Randomization Interval 11111 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

11. doc: IEEE 802.11-06/0388r0March 2006 Submission Kwak, Rudolf, InterDigital 11 Channel Switch Response 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

12. doc: IEEE 802.11-06/0388r0March 2006 Submission Kwak, Rudolf, InterDigital 12 Channel Switch Response Codes

13. doc: IEEE 802.11-06/0388r0March 2006 Submission Kwak, Rudolf, InterDigital 13 Message Sequence for BSS Channel Switch APSTAx Channel Switch Solicitation Other STAs Channel Switch Request[Query] Channel Switch Report(s)[did switch] AP decides to switch and selects: new channel, switch time, response time Channel Switch Announcement Channel Switch Request[Confirm] Channel Switch Response Time Switch Time Required elements in italics, others optional Channel Switch Reports [Query]

14. doc: IEEE 802.11-06/0388r0March 2006 Submission Kwak, Rudolf, InterDigital 14 A recap on 802.11h DFS (1) DFS provides the following functionalities Association of STAs with an AP in a BSS based on the STAs supported channels Quieting the current channel so it can be tested for the presence of radar with less interference from other STAs Testing and detecting channels for radar before using a channel and while operating in a channel based on regulatory requirements Discontinuing operations after detecting radar in the current channel to avoid interference with radar Requesting and reporting of measurements in the current and other channels Selecting and advertising a new channel to assist the migration of a BSS or IBSS after radar is detected

15. doc: IEEE 802.11-06/0388r0March 2006 Submission Kwak, Rudolf, InterDigital 15 A recap on 802.11h DFS (2) Supported Channel capabilities The Supported Channels element contains a list of channel in which a STA is capable of operating. “Supported channel” IE part of Association/Re-association Request frames “Channel Switch Announcement” IE Used by an AP in a BSS to advertise when it is changing to a new channel and the channel number of the new channel Optionally, enforce stop of Tx on current channel until switching time “Channel Switch Announcement” IE attached to Beacon or Probe Response frames Can also sent standalone in Channel Switch Announcement action frame (particularly IBSS case)

16. doc: IEEE 802.11-06/0388r0March 2006 Submission Kwak, Rudolf, InterDigital 16 A recap on 802.11h DFS (3) Measurements Request/Report action frames Measurement Request contains measurement type and configuration (i.e. periodic, once), similar to 11k Measurement Report can be used to alert other STAs about presence of radar Quieting the current channel The Quiet element defines an interval during which no transmission shall occur in the current channel This interval may be used to assist in making channel measurements without interference from other STAs in the BSS or IBSS. Quiet IE attached to the Beacon or Probe Response frames IBSS DFS element Contains information for DFS operation in an IBSS.

17. doc: IEEE 802.11-06/0388r0March 2006 Submission Kwak, Rudolf, InterDigital 17 A recap on 802.11h DFS (4) ESS mode operation AP can configure the quiet interval for measurement purposes AP detects radar signals on its own or via a Measurement Report from STAs AP sends Channel Switch Announcement in the Beacon or Probe Response Can be sent few times to make sure all STAs received it Channel switching time may take up to several hundred of ms’s STA behavior upon reception of the Channel Switch Announcement not specified beyond its obligation to cease transmission on the current channel In particular, a STA may or may not follow to the advertised channel or associate with another BSS IBSS mode operation DFS owner STA detects radar signals on its own or via a measurement report from other STA and sends Channel Switch Announcement frame to all STAs Other STAs are mandated to cease transmission on current channel If other STA detects radar and did not receive channel switch announcement frame from the DFS owner for DFS recovery interval, then STA will start the DFS owner recovery procedure to determine a new DFS owner

18. doc: IEEE 802.11-06/0388r0March 2006 Submission Kwak, Rudolf, InterDigital 18