doc.: IEEE 802.11-12/1093r0 Submission September 2012 Jeongki Kim, LG Electronics Slide 1 System information update procedure for 11 ah Date: 2012-09-17 Authors: Name Affiliations Address Phone Email Jeongki Kim LG Electronics LG R&D Complex Anyang-Shi, Kyungki-Do, Korea +82-31-450- 7808 [email protected]Yongho Seok LG Electronics Jinsoo Choi LG Electronics Jin Sam Kwak LG Electronics Eric Wong Broadcom Sunnyvale, CA +1 408 922 6672 [email protected]Matthew Fischer Broadcom [email protected]om Minyoung Park Intel Hillsboro, OR +1 503 712 4705 minyoung.park@intel .com Adrian Stephens Intel Tom Tetzlaff Intel Emily Qi Intel Simone Merlin Qualcomm San Diego, CA +1 858 845 1243 [email protected]m Santosh Abraham Qualcomm Menzo Wentink Qualcomm Alfred Asterjadhi Qualcomm Amin Jafarian Qualcomm Hemanth Sampath Qualcomm
ChaoChun Wang MediaTekJames Wang MediaTekJianhan Liu MediaTekVish Ponnampalam MediaTekJames Yee MediaTekHuai-Rong Shao Samsung ElectronicsChiu Ngo Samsung ElectronicsMinho Cheong ETRIJae Seung Lee ETRIHyoungjin Kwon ETRIHeejung Yu ETRISok-kyu Lee ETRISun, Bo ZTELv, Kaiying ZTE
Authors:
September 2012
Jeongki Kim, LG Electronics
doc.: IEEE 802.11-12/1093r0
Submission Jeongki Kim, LG ElectronicsSlide 3
Authors:Name Affiliations Address Phone Email
Sayantan Choudhury NokiaTaejoon Kim NokiaKlaus Doppler NokiaChittabrata Ghosh NokiaEsa Tuomaala NokiaKen Mori PanasonicRojan Chitrakar PanasonicHaiguang Wang I2RShoukang Zheng I2RYeow Wai Leong I2RZander Lei I2RJaya Shankar I2RAnh Tuan Hoang I2RJoseph Teo Chee Ming I2R
September 2012
doc.: IEEE 802.11-12/1093r0
Submission
Introduction
• The short beacon frame format is adopted in 11 ah in order to reduce the medium occupancy and reduce the power consumption of STA [1],[2]
• The STA can know if the network configuration information is changed by ‘ change sequence’ in short beacon when the STA receives the short beacon
• For STA to update the changed network configuration information in case that the network configuration information is changed,
– Case 1: the STA may receive the next full beacon
– Case 2: the STA may send the probe request and receive the probe response
• Examples of Case 2– In case that AP does not send the full beacon periodically [1][2]
• E.g., Operation by short beacon + probe request/response w/o full beacon
– When a station receiving short beacon wants to receive the updated information as fast as possible
September 2012
Jeongki Kim, LG ElectronicsSlide 4
doc.: IEEE 802.11-12/1093r0
Submission
Motivation
• In case 2 AP will send the probe response frame including all system information although only one system information element is changed– Note that the size of probe response is similar to the size of beacon
frame in legacy 802.11 system
• It will result in unnecessary medium occupancy
• In this case if AP sends the probe response including only the changed network configuration information, we can reduce the unnecessary medium occupancy
September 2012
Jeongki Kim, LG ElectronicsSlide 5
doc.: IEEE 802.11-12/1093r0
Submission
Proposal
• When the change sequence value in short beacon is different from the value which the station has, the STA will send the AP the probe request frame including change sequence which the station stores
• Whenever the system information is updated, AP will store the previous change sequence and the changed information element’s ID
– E.g, ) In case of change sequence = ‘3’, the stored information by AP. [change sequence = 0, ID = ‘x’], [change sequence = 1, ID = ‘y’], [change sequence = 2, ID = ‘Z’]
• If AP receives from the STA the probe request frame including the change sequence, the AP finds updated information by comparing its change sequence with the received change sequence.
• Then the AP will send the STA the optimized probe response frame including only the updated system information and change sequence about the updated system information
September 2012
Jeongki Kim, LG ElectronicsSlide 6
doc.: IEEE 802.11-12/1093r0
Submission
Analysis (1/2)
• Probe response frame will include the same information elements as beacon frame except for TIM IE
– The size of beacon frame/probe response[1]• > 100 byte(typical 802.11 BSS), > 230 bytes (enterprise environment)
Updated IE Legacy probe response (>100B) in typical 802.11BSS
Legacy probe response (>230B) in enterprise environment
Optimized Probe Response Gain (%)
Optimized Probe Response Gain (%)
Channel Switch Announcement (5B)
17 B > 83% 17 B > 92 %
Quiet element (8B) 20 B > 80% 20 B > 91%
EDCA parameters (20B) 32 B > 68% 32 B > 86%
HT Operation element (24B) 36 B > 64% 36 B > 84%
doc.: IEEE 802.11-12/1093r0
Submission
Summary
• When the system information changes, for AP to send the probe response including full system information may not be efficient in terms of resource overhead.
• For updating the system information, if a STA sends the probe request including the AP’s change sequence which the STA has, the AP can send the optimized probe response including the updated system information
September 2012
Jeongki Kim, LG ElectronicsSlide 9
doc.: IEEE 802.11-12/1093r0
Submission
References
• [1] IEEE 802.11-11/1503r2, Short beacon
• [2] IEEE 802.11-11/1137r9, Proposed Specification Framework for Tgah
• [3] IEEE 802.11-2012, Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications
September 2012
Jeongki Kim, LG ElectronicsSlide 10
doc.: IEEE 802.11-12/1093r0
Submission
Straw poll 1
• SP1: Do you support that a STA may send the probe request frame including the change sequence which the STA has to AP when the STA receives the short beacon including the change sequence which is different from the change sequence which the station stores?– Yes: , No: , Abstain:
• SP2: Do you support that AP may send the optimized probe response frame which includes only system information elements which need to be updated by STA and the change sequence when the AP receives the probe request including the change sequence from the STA?– Yes: , No: , Abstain:
