January 2014 doc IEEE 802 15 14 0110

January 2014 doc. : IEEE 802. 15 -14 -0110 -01 -0 mag Project: IEEE P 802. 15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: MAC Timing related discussion points for of 802. 15. 4 Revision Date Submitted: 25 February 2014 Source: Benjamin A. Rolfe Company: Blind Creek Associates Address: PO Box 798 Los Gatos CA 95031 Voice: +1 408 332 0725, E-Mail: ben @ blindcreek. com Re: Discussion of Timing related parameters and issues Abstract: Initial list of questions for consideration in revision, identify the problems for group attention. Purpose: Progress towards suitable fixes Notice: This document has been prepared to assist the IEEE P 802. 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 P 802. 15. Contribution Slide 1 Ben Rolfe, BCA

January 2014 doc. : IEEE 802. 15 -14 -0110 -01 -0 mag Purpose • Identify the potential timing issues so that • We can figure out which we are going to fix • Figure out which to leave alone • Comment fixing Contribution Slide 2 Ben Rolfe, BCA

January 2014 doc. : IEEE 802. 15 -14 -0110 -01 -0 mag Status • Document in progress (15 -14 -0111 -00 -0 mag) lists all the attributes and constants that specify or affect specification of MAC timing. • Color coded table - what it is and where it came from • Red means issue we probably can’t ignore • Yellow means may need attention • Blue means minor issues (editorial or other obvious fixes) • The facts extracted and summarized • Help see potential problems • Still awork in progress • Guidance from the group – what next? Contribution Slide 3 Ben Rolfe, BCA

January 2014 doc. : IEEE 802. 15 -14 -0110 -01 -0 mag Method • Search standard for PIB attributes, constants and SAP parameters that may control or affect MAC timing • • 802. 15. 4 -2011 802. 15. 4 e-2012 802. 15. 4 f-2012 802. 15. 4 g-2012 802. 15. 4 j-2013. 802. 15. 4 k-2013 Draft P 802. 15. 4 m Draft P 802 -15 -4 p • Examine definition and use of each • Look for complex entanglements (dependencies or complex specs) • Look for changes in amendments which may lead to conflicts • Consider history – what’s been confused and debated • Non-trivial task Contribution Slide 4 Ben Rolfe, BCA

January 2014 doc. : IEEE 802. 15 -14 -0110 -01 -0 mag Red Zone 1. Acknowledgement Timing a) b) c) d) e) 2. LIFs and SIFs a) b) c) d) 3. Complex, PHY specific definitions, some with mixed units Depends on a number of constants and other attributes that have been touched a lot Specified in more than one way and place in the standard Reference point for timers unclear When/if to use CSMA a) More than 4 different CSMA scenarios need addressing Suggestion to replace with single IFS specification Ripples a lot (including into Ack timing) Backwards compatibility issues? Threshold for SIFS a. Turnaround. Time a) Contribution Entangled in a lot of things Slide 5 Ben Rolfe, BCA

January 2014 doc. : IEEE 802. 15 -14 -0110 -01 -0 mag Yellow Zone 1. mac. Response. Wait. Time a) b) 2. mac. Max. Frame. Total. Wait. Time a) b) 3. Used in a number of places where it is maybe should not be; PHY specific but maybe should not be; Differing styles in amendments a. Unit. Backoff. Period not changed by PHY amendments but maybe should have been? mac. Enh. Ack. Wait. Duration a) 6. Used a lot of places, needs review a. Unit. Backoff. Period and a. CCATime a) b) c) d) 5. Complex definition dependent on a bunch of things Set by higher layer but specified like a read-only parameter a. Base. Slot. Duration and a. Base. Superframe. Duration a) 4. Complex definition dependent on attributes and constants that have changed throughout amendments Should review to ensure still valid for all PHYs Needs precise definition of timing reference for transmission time (measured from what to where? ) mac. Min. LIFSPeriod and mac. Min. SIFSPeriod a) Contribution Used but not defined (4 e) Slide 6 Ben Rolfe, BCA

January 2014 doc. : IEEE 802. 15 -14 -0110 -01 -0 mag Blue Zone • PHY dependent timings (6. 4. 3): some things stated as UWB PHY dependent are really ALOHA dependent • mac. Sync. Symbol. Offset needs clean-up • Duty cycle control • mac. Tx. Control. Active. Duration, mac. Tx. Control. Pause. Duration and mac. Tx. Total. Duration • Intended to provide control of transmit duty cycle • Specification confusion (no MAC or PHY function uses them) • CCA Timing w/CCA Mode 4 • Wait phy. CCADuration/a. CCATime and return clear or just return clear? Contribution Slide 7 Ben Rolfe, BCA

January 2014 doc. : IEEE 802. 15 -14 -0110 -01 -0 mag Next Steps TBD Contribution Slide 8 Ben Rolfe, BCA