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Some Additional TPC Aspects to Consider

Some Additional TPC Aspects to Consider. Peter Larsson Ericsson Research peter.larsson@era.ericsson.se. Motivation. Three concerns: TPC Request/Report frames in conjunction with 802.11 Power Management need to be addressed.

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Some Additional TPC Aspects to Consider

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  1. Some Additional TPC Aspects to Consider Peter Larsson Ericsson Research peter.larsson@era.ericsson.se Peter Larsson, Ericsson Research, Sweden

  2. Motivation • Three concerns: • TPC Request/Report frames in conjunction with 802.11 Power Management need to be addressed. • TPC Request/Report frames works fine for downlink power control, but would benefit from additional support in the uplink. • AP centric radar detection would benefit from additional TPC support in the uplink. Peter Larsson, Ericsson Research, Sweden

  3. Power Management and TPC (1) N.B CF-Pollable STAs not considered Beacon Beacon ACK TPC Report AP Time PwrMgt=0 PwrMgt=1 Channel busy STA TPC Request ACK Awake Awake • Power is consumed when being awake. • Why bother, one is anyway sending data immediately after the TPC frames? • Not entirely true! Implementation specific. E.g. after long silence, the first frame should be able to determine a sensible power level. Peter Larsson, Ericsson Research, Sweden

  4. Power Management and TPC (2) N.B Ack response on PS poll not considered Beacon Beacon TIM ACK TPC Report AP Time PwrMgt=1 PwrMgt=0 STA TPC Request PS Poll ACK Awake Awake Awake Peter Larsson, Ericsson Research, Sweden

  5. The Proposal Beacon Beacon AP Time Transmit Power indication Transmit Power indication STA Awake Awake • Exploit 802.11 power save philosophy, i.e. wake up at TBTT, wait for beacon, do what is needed, then go back to sleep. • Complement with transmit power indication in Beacon in addition to existing TPC frames Peter Larsson, Ericsson Research, Sweden

  6. TPC UL/DL N.B Commonly, not all STAs do TPC in one frame time UL DL Message complexity = O(N) Active and precise TPC Message complexity = O(N) Active and precise TPC Beacon Beacon Beacon ACK Beacon ACK ACK ACK TPC Rep TPC Req TPC Req TPC Rep TPC Req./ Rep. AP AP Time Time ACK ACK ACK ACK TPC Rep TPC Rep TPC Req TPC Req STA STA STA 2 STA N STA 2 STA N STA 1 STA 1 Message complexity = O(1) Passive TPC. Reduced powerconsumption. Not useful TPC Beacon Beacon Beacon AP Time STA STA 1,2,…N STA 1,2,…N Peter Larsson, Ericsson Research, Sweden

  7. AP Centric Radar Detection • 2 complementary mechanisms for radar detection. • Medium silencing • TPC in UL • Regular TPC updates, in addition to on demand updates (i.e. TPC Req/Rep) will ease radar detection. Peter Larsson, Ericsson Research, Sweden

  8. Proposed alternatives • Alternative 1. • 8 bit IE payload containing transmit power indication. • Alternative 2. • 16 bit IE payload containing8 bit transmit power indication and 8 bit estimated interference level • Alternative 1+2=3. • 8 bit IE payload containing two fields in alt 2 added together.See 02/069 p.9. N.B. this is compatible with alt 1. Peter Larsson, Ericsson Research, Sweden

  9. Conclusion • It was suggested that beacons contain transmit power information. • The beacon TP indication will complement the TPC request/ report method. • The proposal provides: • A 802.11 power management compatible TPC mechanism for UL. • Improved medium efficiency for UL • Improved means for radar detection. Peter Larsson, Ericsson Research, Sweden

  10. Two Ways Forward • Consider the power save, UL complexity & radar detection issues in conjunction with TPC later in the LB process. • Including TP level indication in the beacon may then be a recommended amendment. • Consider this issue this meeting and amend necessary beacon IE format/text in the draft. Peter Larsson, Ericsson Research, Sweden

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