doc.: ieee 802.11-11/0060r1 submission january 2011 minyoung park, intel corp.slide 1 low power...
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doc.: IEEE 802.11-11/0060r1
Submission
January 2011
Minyoung Park, Intel Corp.Slide 1
Low Power Capability Support for 802.11ah
Date: 2011-01-17
Name Affiliations Address Phone email Minyoung Park Intel Corp. 2111 NE 25th Ave.
Hillsboro OR 97229 503 712 4705 [email protected]
Emily Qi Intel Corp. [email protected]
Authors:
doc.: IEEE 802.11-11/0060r1
Submission
January 2011
Minyoung Park, Intel Corp.Slide 2
Abstract
• This presentation proposes low power capability support for 802.11ah
doc.: IEEE 802.11-11/0060r1
Submission
Previous Presentation on 802.11ah Usages and Power Consumption Analysis
• Doc#: IEEE 802.11-10/1268r0
• Usages– Smart metering (electricity, gas, water, …)
– Sensors (home, health, building, …)
– Collecting information from wireless sensing devices
• Traffic– Low duty cycle: data may be collected every few minutes, hours, or days
– Small packet sizes: 10s or 100s of bytes
• Wireless sensing devices (Low-Power STAs)– Battery powered and low-cost
– Multiple years of battery life
• Multiple years of battery life can be achieved by – Low sleep state power consumption
– Low duty cycle
January 2011
Minyoung Park, Intel Corp.Slide 3
doc.: IEEE 802.11-11/0060r1
Submission
Motivation
• AP does not know limited capabilities of Low-Power STAs
• AP does not treat Low-Power STAs differently from the other STAs
• Example: BSS Max Idle period (802.11v)– AP has only one Max Idle period which allows the STAs to be associated for the Max
Idle period without sending any frames to the AP
• Low-Power STAs need to be treated differently from the other STAs
January 2011
Minyoung Park, Intel Corp.Slide 4
AP
STAs without low power constraintNeed to transmit frames to the AP every 60 secs
Low-Power STAs which need to sleep for 10s of minutesalso need to wakeup and send frames to the APevery 60 secs; otherwise they are disconnectedand need to reassociate when they wakeup.
A single Max Idle Period = 60 secs
doc.: IEEE 802.11-11/0060r1
Submission
Low Power Capability Support
• Provide low power capability support for Low-Power STAs• Low Power Capability element
– A mechanism to exchange low power capability information between an AP and Low-Power STAs so that the AP can treat the Low-Power STAs differently from the rest of the other associated STAs
– Exchanged in (Re)Association Request/Response frames– Format
– Low Power Capability Info field• Variable in length• Example: Max Idle Period field
January 2011
Minyoung Park, Intel Corp.Slide 5
Element ID Length Low Power Capability Info
1 1 variableOctets:
Max Idle Period
2Octets:
...
doc.: IEEE 802.11-11/0060r1
Submission
Example: Max Idle Period
January 2011
Minyoung Park, Intel Corp.Slide 6
• Max Idle Period field in Low Power Capability Info field
• Low-Power STA asks the AP to use the Max Idle Period value set in the Low Power Capability element in the (Re)Association Request frame
• If the AP can support the Max Idle Period value in the (Re)Association Request frame, the AP sets the same or a larger Max Idle Period value in the Low Power Capability Info field in the (Re)Association Response frame
AP STAs without low power constraint Need to transmit frames to the AP every 60 seconds
Low Power STAs can sleep for 30 minutes without being disconnected from the AP
AP applies different Max Idle periods for different classes of STAs- STAs without low power constraint: 60 seconds- Low-Power STAs: 30 minutes
doc.: IEEE 802.11-11/0060r1
Submission
Summary
• Wireless sensing devices in the 802.11ah usage model– Expected to be battery powered
– Require multiple years of battery life
– Low power consumption
– Low cost
• Proposed low power capability support for Low-Power STAs
• Low Power Capability element– Low-Power STAs provide their limited capability information to the AP
– The AP treats the Low-Power STAs differently from the other STAs to support low power consumption
January 2011
Minyoung Park, Intel Corp.Slide 7