doc.: IEEE /0588r0 Submission PHY power saving feature considerations Slide 1 May 2010 Yujin Noh, LG Electronics Date: Authors: NameAffiliationAddressPhone Yujin NohLG Electronics, Inc. LG R&D Complex 533, Hogye- 1dong, Dongan-Gu, Anyang-Shi, Kyungki-Do, , Korea Daewon LeeLG Electronics, Inc. LG R&D Complex 533, Hogye- 1dong, Dongan-Gu, Anyang-Shi, Kyungki-Do, , Korea Yongho SeokLG Electronics, Inc. LG R&D Complex 533, Hogye- 1dong, Dongan-Gu, Anyang-Shi, Kyungki-Do, , Korea Bonghoe KimLG Electronics, Inc. LG R&D Complex 533, Hogye- 1dong, Dongan-Gu, Anyang-Shi, Kyungki-Do, , Korea

doc.: IEEE /0588r0 Submission Introduction Different Usage Models for efficient power consumption Consideration aspects for less-overhearing May 2010 Yujin Noh, LG ElectronicsSlide 2

doc.: IEEE /0588r0 Submission Concerns over global warming Worldwide issues such as the greenhouse effect and global warming In order to solve the concerns over global problem, there have been ongoing efforts: –Copenhagen Accord for new climate change treaty as a result of the U.N. Climate Change Conference in Copenhagen, Denmark New framework to reduce global warming –Energy Star as a voluntary labeling program to identify and promote energy efficient consumer products like computers, monitors and consumer electronics Saving money and protecting the environment through energy efficient products and practices that generally use 20-30% less energy Technologies to be introduced for 11ac should be in line with the strong trend of low power consumption May 2010 Yujin Noh, LG ElectronicsSlide 3

doc.: IEEE /0588r0 Submission Networked Home Multi-media Streaming Distributed Consumer Electronics(CE) around the AP –More than one device of the networked home is likely to be communicated with one shared AP –Direct data transmission between distributed CEs to support robust HD video streaming and surveillance (e.g. Direct Link Setup, WiFi Direct) May 2010 Yujin Noh, LG ElectronicsSlide 4 Surveillance Camera HD Video Streaming Data Transfer DLS MU-MIMO

doc.: IEEE /0588r0 Submission Portable AP devices Increased mobile units supporting the internet access for outdoor as well as indoor –Portable AP devices (e.g. KT Wibro Egg, Sprint Overdrive) will require better power management –Power save features even for AP may be important Slide 5 May 2010 Yujin Noh, LG Electronics

doc.: IEEE /0588r0 Submission Previous approaches for power saving With CSMA/CA based, each STA needs to be enforced to listen to the channel to know about the current status regardless of its own data communication with AP –Some method for power saving to reduce the time required for STA to listen to the channel –Basic power save mode switching between awake state and sleep state with PS-Poll frame from STAs –APSD (Automatic Power Save Delivery) considering QoS- sensitive applications additionally –PSMP (Power Save Multi-Poll) reducing the contention between STAs and between STA and AP In case of the high throughput to be supported, less chance to sleep due to a lasting awake state supporting reasonable QoS –Consumer need for efficient power consumption even during awake state for the consumer electronics Slide 6 May 2010 Yujin Noh, LG Electronics

doc.: IEEE /0588r0 Submission Considerations for Power Save in PHY Information to indicate whether or not to listen and decode the data packet Data non-reception STAs can switch to sleep state after decoding VHT-SIG (VHT-SIGA or VHT-SIGB) Consideration aspects –AP and STA have different required power efficiency at the transceiver –Efficient power management of STA is typically more desirable with the exception of mobile AP devices May 2010 Yujin Noh, LG ElectronicsSlide 7

doc.: IEEE /0588r0 Submission Use cases for Micro-Sleep during Active State Observation –Data transmission can be categorized into 3 links Scenario 1 : AP-to-STA Scenario 2 : STA-to-AP Scenario 3 : STA-to-STA (DLS, Direct Link Setup) May 2010 Yujin Noh, LG ElectronicsSlide 8

doc.: IEEE /0588r0 Submission Micro-Sleep during Active State Consideration aspect 1 (STA-to-AP transmission, UL) –Data reception at AP –No need for all STAs to overhear UL data packet (not intended user) –Possibility of power save information in VHT-SIG to allow Rx micro sleep for all STAs May 2010 Yujin Noh, LG ElectronicsSlide 9

doc.: IEEE /0588r0 Submission Micro-Sleep during Active State Consideration aspect 2 (AP-to-STA transmission, DL) –Only a single (or subset) of STAs in BSS require data reception –STAs require information on whether or not to demodulate/decode received signal from AP for power saving –Possibility of the PHY ID (e.g. Association ID) concept to indicate intended receiving STA (or STAs), which allows Rx micro-sleep on subset of STAs May 2010 Yujin Noh, LG ElectronicsSlide 10

doc.: IEEE /0588r0 Submission Micro-Sleep during Active State Consideration aspect 3 (STA-to-STA, DLS) –STA1 and STA2 are paired for DLS operation It is assumed that STA1 transmits data packet to STA2 directly STA2 requires information on whether or not to demodulate/decode the received signal for power saving Possibility of indicate PHY ID for DLS –Note : current specification does not support Association ID for DLS May 2010 Yujin Noh, LG ElectronicsSlide 11

doc.: IEEE /0588r0 Submission Signaling for the Micro-Sleep Feature Link differentiation between DL and UL –Simple because potentially 1 bit in VHT-SIG is required –Efficient signaling in UL point of view Introduce the PHY ID in VHT-SIG –It can work well for Rx STAs in case of DL –One potential candidate : Association ID of STA (11bits) –Issues for further study Restriction of the PHY ID bit width due to limited size of VHT-SIG The practical number of STAs which can be controlled by AP concurrently –Partial AID with N bits (TBD, less than 11bits) May 2010 Yujin Noh, LG ElectronicsSlide 12

doc.: IEEE /0588r0 Submission Partial AID for the Micro-Sleep Feature Example of Partial AID –It is assumed that AP transmits data packets to STA3 –Micro sleep mode after decoding of the partial AID in case of STA1 and STA2 May 2010 Yujin Noh, LG ElectronicsSlide 13 STA3: AID = 1075 Partial AID =51 * Partial AID = 51 STA2: AID = 1052 STA1: AID = 1054 *Note : 1075 mod 64 = 51 Partial AID =28 Partial AID =30

doc.: IEEE /0588r0 Submission Summary In general, support of power saving during active state seems important. We have identified few transmission qualities which may be exploited for power saving –Realization of Link differentiation –Realization of PHY ID in VHT-SIG Details of how to support power saving during active state needs discussion. Detailed signaling aspects of VHT-SIG needs further study May 2010 Yujin Noh, LG ElectronicsSlide 14