Consideration on Max Idle Period Extension for 802.11ah Power Save July 2011 doc.: IEEE 802.11-11/xxxxr0 Consideration on Max Idle Period Extension for 802.11ah Power Save Date: 2012-01-19 Authors: ZTE Corporation ZTE Corporation

July 2011 doc.: IEEE 802.11-11/xxxxr0 Abstract The target of this presentation is to provide some considerations on Max Idle Period extension for 802.11ah power save. ZTE Corporation ZTE Corporation

Transmission Characteristics of 11ah Use Case [1] No. Use Cases STA/AP communication Traffic type STA Capacity 1a Smart Grid 2-way (meter data & control) Continuous/periodic/burst 6000 1c Environ./Agri. Mon. 2-way (monitoring data and control; mostly monitoring) Periodic, event-based 300 1d Industrial Process Automation Periodic (0.1s~100s), Burst 500 1e Indoor Healthcare System 50 1f Healthcare/Fitness Periodic: few 100 bytes every minute Event-based: few 100 bytes per event 50 (multi-story center can have higher density) 1g Home/Building Automation/Control 50~100 1h Temperature Sensor Network 5~20 3a Outdoor Extended Range Hot Spot Burst/permanent 3b Outdoor Wi-Fi for Cellular Offloading ZTE Corporation

Motivation In this presentation, we discuss the power save for 11ah use cases with Very long reporting interval and little downlink control message transfer, for example, Gas detector only need to transfer alarm message & data to AP, the detector potentially may sleep several days or even longer. In some smart grid use cases, meters report the data with very long period (more than one day) for only charge requirement. Current 11v BSS Max Idle Period management scheme couldn’t satisfy the requirements of these 11ah use cases. All of STAs in the BSS are deployed the same Max Idle Period by the AP; The length of Max Idle Period is less than 1 day (~18.64hrs) ZTE Corporation

Problems of support both mobile devices and sensors In current BSS Max Idle Period management scheme, all of STAs in the BSS are deployed the same Max Idle Period by the AP. If 11ah sensors are set to the same value of several minutes as mobile phone, It will be a big power consumption for 11ah battery-powered sensors. There may be a large number of keep-alive messages occupy the channel resources frequently, channel access competition and access delay may be a big problem. To save power of sensors in these use cases, AP should support multiple max idle period management scheme ZTE Corporation

Power Save for very long transmission duty cycle (~days) July 2011 doc.: IEEE 802.11-11/xxxxr0 Power Save for very long transmission duty cycle (~days) Current length of BSS Max Idle Period is only ~18.64hrs (16bit with unit of 1000TU). Suppose AP supports longer max idle period (~days) with ultra low sleep power consumption, STA could sleep longer than 18hrs to save more power, without sending keep-alive frame every 18hrs. By keep association with AP, if emergency situation happens, STA can quickly wake up and report important data to AP. Besides, STA can response to event-based query/control message from AP by periodically listen to TIM message. ZTE Corporation ZTE Corporation

Power Save for very long transmission duty cycle (~days) July 2011 doc.: IEEE 802.11-11/xxxxr0 Power Save for very long transmission duty cycle (~days) One of the simply solution is to enlarge the unit of Max Idle Period, e.g. from ‘1000TU’ (1s) to ‘10000TU’ (10s), so that the length of Max Idle Period will be extended from ~18.64hrs to ~186hrs (7.75days) . Idle Options: ZTE Corporation ZTE Corporation ZTE Corporation

Summary Multiple Max Idle Period management extension for Support both mobile devices and sensors Very long Max Idle Period management extension (~days) for support related 11ah use cases One of the simply solution is to change the unit of Max Idle Period, so that the length of Max Idle Period will be extended longer than ~18hrs. ZTE Corporation

Reference [1] 11-11-0457-00-00ah-potential-compromise-of-802-11ah-use-case- document [2] 802.11v-2011 [3] 11-11-0985-01-00ah-performance-evaluation-of-multiple-STAs’- authentication-and-association-process [4]11-11-1204-00-00ah-power-saving-mechanism-consideration-for- 802.11ah-framework [5] 11-11-0060-01-00ah-low-power-capability-support-for-802-11ah ZTE Corporation

Straw Poll 1 Do you support the concept of very long Max Idle Period (~days) extension for better support related 11ah use cases? Y: N: A: Slide 10 ZTE Corporation Minyoung Park, Intel Corp.

Straw Poll 2 Do you support the concept of very long Max Idle Period (~days) by simply change the unit of Max Idle Period, so that the length of Max Idle Period will be extended longer than ~18hrs? Y: N: A: Slide 11 ZTE Corporation Minyoung Park, Intel Corp.

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Power Save for very long transmission duty cycle (~days) July 2011 doc.: IEEE 802.11-11/xxxxr0 Power Save for very long transmission duty cycle (~days) If the sensor is disassociated with AP until requirement of burst data transmission Num of STAs Authentication and association time (s) 50 1.2073 100 1.8012 200 2.6550 500 4.6366 900 11.2495 1000 12.345 1500 82.9897 2000 152.024 2500 238.603 3000 323.556 To meet the requirement, successful and faster association process is needed to satisfy the delay requirement and security requirement for these time-sensitive and life/property-related important data transmission, especially for burst data transmission by large number of STAs at the same time due to emergency event happens such as fire disaster.[3] AP also needs to check the status of sensor or query sensor occasionally. How disassociated- STA quickly responses to this event-based query/control message from AP ? ZTE Corporation ZTE Corporation