Submission Title: IEEE802.15.3: Overview of Power Save Proposal. September 2001 Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: IEEE802.15.3: Overview of Power Save Proposal. Date Submitted: 19 September, 2001 Source: Jay Bain Company: Time Domain Address: 7057 Old Madison Pike Voice: 256 922 9229 , FAX: 256 922 0853, E-Mail: jay.bain@timedomain.com Source: Mark E. Schrader Company: Eastman Kodak Co. Address: 4545 East River Road, Rochester, NY 14650-0898 Voice: 716-781-9561 , FAX: 716-781-9533, E-Mail: mark.e.schrader@kodak.com Abstract: This provides an overview of additional proposals on Power Management for incorporation into the draft 0.8. Text is in 01/430r0 Purpose: To provide information and solicit comments on proposed power management updates Notice: This document has been prepared to assist the IEEE P802.15. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P802.15 Jay Bain Time Domain, Mark Schrader Eastman Kodak

Topics of proposal (mostly from 01/425r0 and editor notes in d0.7) September 2001 Topics of proposal (mostly from 01/425r0 and editor notes in d0.7) Wake-on-WPAN – Jay Bain Unused bits in CTA to indicate mode and next active SF – Mark Schrader Null-CTA element – Mark Schrader Current EPS state in device information request – John Barr Definitions of EPS and related terms – Jay Bain Jay Bain Time Domain, Mark Schrader Eastman Kodak

September 2001 Wake on WPAN Transition from EPS to Active mode in an EPS DEV develops MLME-POWERMGT.indication primitive. Structure in place in d0.7, 6.3.1.3. Add tie between the 7.5.x commands changing modes or indication of data and the clause 6 primitives. Add this text in clause 8. Consider addition of means for enable/disable of the indication as a PIB item. Add differentiation of Wake to consider the three CTA characters (awake, EPS, momentary) Jay Bain Time Domain, Mark Schrader Eastman Kodak

CTA Mode SST/NAB Switch September 2001 Unused CTA Bits CTA Mode SST/NAB Switch Jay Bain Time Domain, Mark Schrader Eastman Kodak

Outline Issues from previous proposal New CTA bits definitions August 2001 Outline Issues from previous proposal New CTA bits definitions Advantages Impact Jay Bain Time Domain, Mark Schrader Eastman Kodak

August 2001 Issue1 There is no explicit indication in the CTA element if it is an AWAKE or an EPS type. There is a difference: If EPS CTA then the DEV will not be awake for each beacon If AWAKE CTA then the DEV will be awake Jay Bain Time Domain, Mark Schrader Eastman Kodak

September 2001 Issue 2 When a station is sleeping there is no beacon info. communicated about the state of the DEV. Information: Is it in EPS mode or AWAKE mode? When will the source be waking up or simply having its next time (low QoS) slot? For destination DEVs losing beacons/synchronization For a station wanting to establish a stream Jay Bain Time Domain, Mark Schrader Eastman Kodak

September 2001 Issue 3 CTA elements are added and omitted from the header depending on whether the DEV has a slot (or will be awake) in that superframe. This may be more work for the PNC then always having the CTA element and modifying the values of CTA fields periodically. Jay Bain Time Domain, Mark Schrader Eastman Kodak

Current CTA Element Fields September 2001 Current CTA Element Fields Destination DEV address = 1B Source DEV address = 1B Slot Start Time = SST = 2B Stream ID = 1B Unused = 1B Jay Bain Time Domain, Mark Schrader Eastman Kodak

Proposed Use of Two Unused CTA Bits September 2001 Proposed Use of Two Unused CTA Bits Bit 0: CTA Element Type & DEV Mode 0 = AWAKE CTA Element Type 1 = EPS CTA Element Type Bit 1: SST/NAB Field Definition 0 = The field is the Slot Start Time, SST, as in previous slide and the current draft D07, p78. 1 = Next Active Beacon, NAB. The field is defined as, the 2 LSB’s of the beacon number, of the next superframe in which the DEV will have a time slot (or if asleep, wake up). Jay Bain Time Domain, Mark Schrader Eastman Kodak

Result of These Changes September 2001 Result of These Changes An AWAKE DEV with a time slot every N superframes will always have a CTA element. A device that is asleep (EPS mode) will always have a CTA element. Other DEVs reading the a CTA element always know the mode of that DEV, and either the slot time or the beacon number of the next time slot. Jay Bain Time Domain, Mark Schrader Eastman Kodak

September 2001 What is the Impact? CTA element values will not change any more often than before. Important for the “CTA change bit”. CTA adds/deletes will occur less often then before. The PNC will post the: CTA mode associated with a CTA element. next SF in which a slot will occur if it is not in this SF. Jay Bain Time Domain, Mark Schrader Eastman Kodak

Impact Tradeoff: CTA Position September 2001 Impact Tradeoff: CTA Position CTA elements with Bit 1 set to 1, NAB CTAs, are positioned as the first entries in the beacon. Pro: Computing the time slot durations of SST CTAs will be uniform for all SST CTAs and NAB CTAs will be easily located. Con: CTA elements will have to be moved by the PNC when Bit 1, changes state. Jay Bain Time Domain, Mark Schrader Eastman Kodak

September 2001 CTA elements with Bit 1 set to 1, NAB, are positioned in the same place as the same element with Bit 1 set to 0, SST. Pro: All CTA elements are always in the same order and position in the Beacon. Con: The duration of the time slot specified by a SST CTA, which is located just before a NAB CTA, requires finding the next SST CTA element in the sequence. (The slot duration is the difference between the two successive slot start times.) = more complex algorithm. Jay Bain Time Domain, Mark Schrader Eastman Kodak

Global Advantages The mode is always posted. September 2001 Global Advantages The mode is always posted. Network robustness and synchronization will be improved: If: hhThhhThhhDhhh Then: the next beacon will be enough to restore the lost beacon information regardless of mode or QoS. Minimal additional PNC overhead. Jay Bain Time Domain, Mark Schrader Eastman Kodak

Null CTA Element September 2001 Jay Bain Time Domain, Mark Schrader Eastman Kodak

September 2001 Definition The null CTA element is a SST CTA element with the same slot start time as the next SST CTA element listed in the beacon. It is used to indicate that a sleeping device is awake on this superframe to listen to the beacon, but does not have a time slot allocated. Jay Bain Time Domain, Mark Schrader Eastman Kodak