1. doc.: IEEE 802.11-13/0042r1 Submission January 2013 Yongho Seok, LG ElectronicsSlide 1 Fast Moving Scan Channel Date: 2013-01-07 Authors: NameAffiliationsAddressPhoneEmail Yongho SeokLG Electronics LG R&D Complex Anyang-Shi, Kyungki- Do, Korea +82-31-450-1947yongho.seok@lge.com Giwon ParkLG Electronics Qi WangBroadcom Matthew FischerBroadcom Ron ProatBroadcom

2. doc.: IEEE 802.11-13/0042r1 Submission Abstract The presentation proposes an improvement to the Active Scanning mechanism in 2.4GHz ISM band to reduce the scanning time on unused channels. January 2013 Yongho Seok, LG ElectronicsSlide 2

3. doc.: IEEE 802.11-13/0042r1 Submission Conformance w/ TGai PAR & 5C January 2013 Yongho Seok, LG ElectronicsSlide 3 Conformance QuestionResponse Does the proposal degrade the security offered by Robust Security Network Association (RSNA) already defined in 802.11? No Does the proposal change the MAC SAP interface?No Does the proposal require or introduce a change to the 802.1 architecture?No Does the proposal introduce a change in the channel access mechanism?No Does the proposal introduce a change in the PHY?No Which of the following link set-up phases is addressed by the proposal? (1) AP Discovery (2) Network Discovery (3) Link (re-)establishment / exchange of security related messages (4) Higher layer aspects, e.g. IP address assignment 1

4. doc.: IEEE 802.11-13/0042r1 Submission Motivation In 2.4GHz ISM band, a STA scans the channel from Channel Number 1 to Channel Number 13. For each channel to be scanned: –Wait until the ProbeDelay time has expired or a PHYRxStart.indication primitive has been received. –Perform the Basic Access procedure as defined in 9.3.4.2. –Send a probe request to the broadcast destination address, with the SSID and BSSID from the MLME-SCAN.request primitive. When the SSID List is present in the MLME-SCAN.request primitive, send one or more probe request frames, each with an SSID indicated in the SSID List and the BSSID from the MLME-SCAN.request primitive. –Set to 0 and start a ProbeTimer. –If PHY-CCA.indication (busy) primitive has not been detected before the ProbeTimer reaches MinChannelTime, then set NAV to 0 and scan the next channel, else when ProbeTimer reaches MaxChannelTime, process all received probe responses. –Set NAV to 0 and scan the next channel. January 2013 Yongho Seok, LG ElectronicsSlide 4

5. doc.: IEEE 802.11-13/0042r1 Submission Motivation If other BSSs occupy adjacent channels of a scan channel, the transmission from other BSSs may trigger the PHY-CCA.indication (busy) primitive. If there is no BSS occupying the current scan channel, the scan time overhead is increased to MaxChannelTime - MinChannelTime. January 2013 Yongho Seok, LG ElectronicsSlide 5

6. doc.: IEEE 802.11-13/0042r1 Submission Proposed FILS Active Scanning Procedure For each channel to be scanned: –Wait until the ProbeDelay time has expired or a PHYRxStart.indication primitive has been received. –Perform the Basic Access procedure as defined in 9.3.4.2. –Send a probe request to the broadcast destination address, with the SSID and BSSID from the MLME-SCAN.request primitive. When the SSID List is present in the MLME-SCAN.request primitive, send one or more probe request frames, each with an SSID indicated in the SSID List and the BSSID from the MLME-SCAN.request primitive. –Set to 0 and start a ProbeTimer. –If PHY-CCA.indication (busy) primitive has not been detected before the ProbeTimer reaches MinChannelTime, then set NAV to 0 and scan the next channel, else when ProbeTimer reaches MaxChannelTime, process all received probe responses. –If PHY-RxStart.indication primitive has not been received before the ProbeTimer reaches MinChannelTime, then STAs with dot11FILSActivated equal to true sets NAV to 0 and scans the next channel –Set NAV to 0 and scan the next channel. January 2013 Yongho Seok, LG ElectronicsSlide 6

7. doc.: IEEE 802.11-13/0042r1 Submission Probe Request DATA ACK MinChannelTime MaxChannelTime DATA ACK PHY-CCA.indication (busy) Probe Request MinChannelTime MaxChannelTime PHY-RxStart.indication& PHY-CCA.indication (busy) Probe Response If PHY-CCA.indication (busy) primitive has been detected before the ProbeTimer reaches MinChannelTime, then STA scans the channel until ProbeTimer reaches MaxChannelTime. If PHY-CCA.indication (busy) primitive has been detected before the ProbeTimer reaches MinChannelTime, then STA scans the channel until ProbeTimer reaches MaxChannelTime. Slide 7Yongho Seok, LG Electronics

8. doc.: IEEE 802.11-13/0042r1 Submission Probe Request DATA ACK MinChannelTime DATA ACK Probe Request MinChannelTime MaxChannelTime PHY-RxStart.indication& PHY-CCA.indication (busy) Probe Response If PHY-RxStart.indication primitive has not been received before the ProbeTimer reaches MinChannelTime, then STAs with dot11FILSActivated equal to true sets NAV to 0 and scans the next channel PHY-CCA.indication (busy) If PHY-RxStart.indication primitive has been received before the ProbeTimer reaches MinChannelTime, then STA scans the channel until ProbeTimer reaches MaxChannelTime. Slide 8Yongho Seok, LG Electronics

9. doc.: IEEE 802.11-13/0042r1 Submission Proposed FILS Active Scanning Procedure In many countries, the non-overlapping channel set (1, 5, 9, 13 or 1, 6, 11) is recommended. When only 1, 5, 9, 13 channels are occupied, the proposed FILS active scanning procedure can reduce the scanning time from MaxChannelTime*13 to MaxChannelTime*4 + MinChannelTime*9 –MinChannelTime: 5ms –MaxChannelTime: 10ms –The gain of the scanning time is about 34% (from 130ms to 85ms) January 2013 Yongho Seok, LG ElectronicsSlide 9

10. doc.: IEEE 802.11-13/0042r1 Submission Conclusion In 2.4GHz ISM band, as IEEE 802.11n 40MHz BSS is more crowded, PHY-CCA.indication (busy) probability on adjacent channels is more increasing. This presentation proposes to scan the next channel if a STA does not receive a valid PLCP header during MinChannelTime. January 2013 Yongho Seok, LG ElectronicsSlide 10

11. doc.: IEEE 802.11-13/0042r1 Submission Straw Poll Do you support to include the following condition in FILS active scanning procedure for fast moving scan channel? –If PHY-RxStart.indication primitive has not been received before the ProbeTimer reaches MinChannelTime, then STAs with dot11FILSActivated equal to true sets NAV to 0 and scans the next channel January 2013 Yongho Seok, LG ElectronicsSlide 11