IEEE 802.11-18/0461r0 VHTz Sounding Protocol Details
Gain insights into the IEEE 802.11-18/0461r0 VHTz Sounding Protocol, focusing on NDP initiation, processing times, immediate and delayed feedback mechanisms, and more. Understand the intricacies of exchange timings, ToA calculations, hardware vs. firmware/software implementations, and FTM setup details. Explore how the protocol handles unscheduled scenarios and ensures efficient communication between initiators and responders. Dive deep into the processing delays and feedback loops essential for seamless data transmission.
Download Presentation
Please find below an Image/Link to download the presentation.
The content on the website is provided AS IS for your information and personal use only. It may not be sold, licensed, or shared on other websites without obtaining consent from the author. If you encounter any issues during the download, it is possible that the publisher has removed the file from their server.
You are allowed to download the files provided on this website for personal or commercial use, subject to the condition that they are used lawfully. All files are the property of their respective owners.
The content on the website is provided AS IS for your information and personal use only. It may not be sold, licensed, or shared on other websites without obtaining consent from the author.
E N D
Presentation Transcript
February, 2018 doc.: IEEE 802.11-18/0461r0 VHTz Sounding: MinToaReady Date: 2018-02-20 Authors: Name Christian Berger Marvell Affiliations Address Phone 408-222-9494 crberger@marvell.com email 5488 Marvell Ln, Santa Clara, CA 5488 Marvell Ln, Santa Clara, CA liwenchu@marvell.com Liwen Chu Marvell Submission Slide 1 Berger et al., Marvell
February, 2018 doc.: IEEE 802.11-18/0461r0 VHTz Sounding Protocol NDP-A NDP Initiator Initiator SIFS SIFS SIFS SIFS NDP LMR Responder Responder SIFS Protocol is completely unscheduled When medium is idle, initiator can send NDP-A followed by NDP If available, responder replies with NDP within SIFS Followed by LMR within SIFS, which contains Time stamps t2/t3 of this exchange, or Time stamps t2/t3 of a previous exchange, or No time stamps, if none are ready Submission Slide 2 Berger et al., Marvell
February, 2018 doc.: IEEE 802.11-18/0461r0 Processing Time NDP-A NDP Processing Time Initiator Initiator SIFS SIFS SIFS SIFS NDP LMR Responder Responder SIFS t2 t3 Initiator needs feedback from responder T2 time-of-arrival (ToA) of NDP send by initiator T3 time-of-departure (ToD) of NDP send by responder The time available to determine t2 is about 70-80 s 2 SIFS = 32 s VHT NDP = 40-52 s (1-4 LTF) Submission Slide 3 Berger et al., Marvell
February, 2018 doc.: IEEE 802.11-18/0461r0 Processing Time (cont.) To determine an accurate ToA requires FFT processing Implementations can be in Hardware (delay on order of 10s of s) Firmware/software (delay on order of ms) Processing delay can depend on Bandwidth Number or receive antennas Number of LTF received Current load of other processing (firmware/software) Submission Slide 4 Berger et al., Marvell
February, 2018 doc.: IEEE 802.11-18/0461r0 Immediate and Delayed Feedback Immediate Feedback Sounding Sequence 1 LMR 1 Sounding Sequence 2 LMR 2 Time [ms] Delayed Feedback Min Processing Time Empty LMR Sounding Sequence 1 Sounding Sequence 2 LMR 1 Time [ms] Submission Slide 5 Berger et al., Marvell
February, 2018 doc.: IEEE 802.11-18/0461r0 Delayed Feedback MaxToaAvailable MinToaReady Sounding LMR Availability Time [ms] FTM Setup/Negotiation Responders declares MinToaReady Tells the initiator when to expect measurement results availability After this interval the initiator can expect the time stamps t2/t3 to be included in next LMR Responder also declares MaxToaAvailable Tells the initiator for how long will the measurement results t2/t3 of previous sounding sequence instance will be stored If no subsequent sounding sequence is exchanged for a duration of MaxToaAvailable past the measurement responder may discarded t2/t3 Submission Slide 6 Berger et al., Marvell
February, 2018 doc.: IEEE 802.11-18/0461r0 MinToaReady and MaxToaAvailable MinToaReady Definition Represented as one octet in increments of 100 s Range is 0 to 25.5 ms MaxToaAvailable Definition Represented as a 4 bit exponent MaxToaAvailableExp Value is calculated as MaxToaAvailable = 2^(MaxToaAvailableExp+8) ms Range is 256 ms to 140 minutes Submission Slide 7 Berger et al., Marvell
February, 2018 doc.: IEEE 802.11-18/0461r0 MinToaReady NDP-A NDP Initiator Initiator SIFS SIFS SIFS SIFS NDP LMR Responder Responder SIFS t1/t2 t3/t4 Set by Responder Processing can start after receiving the NDP (t3) Needs to have results ready before preparing LMR in next sequence Used by Initiator to Set Timer Knows sounding was successful after receiving NDP in reply (t4) Can only initiate next sounding after timer expires Submission Slide 8 Berger et al., Marvell
February, 2018 doc.: IEEE 802.11-18/0461r0 MaxToaAvailable NDP-A NDP Initiator Initiator SIFS SIFS SIFS SIFS NDP LMR Responder Responder SIFS t1/t2 t3/t4 Set and Used by Responder to Set Timer Depends on storage capabilities Needs to receive and decode next NDP-A before timer expires (t2) Also Used by Initiator to Set Timer Potentially use same timer as MinToaReady Needs to transmit next NDP-A so that responder can receive and decode before timer expires Submission Slide 9 Berger et al., Marvell
February, 2018 doc.: IEEE 802.11-18/0461r0 Definition of Start and End Points End Start MaxToaAvailable/ MinToaReady NDP-A NDP Initiator Initiator SIFS SIFS SIFS SIFS NDP LMR Responder Responder SIFS t3/t4 t1/t2 MinToaReady and MaxToaAvailable are measured Starting at t4/t3 and ending at t1/t2 for the initiator and responder respectively Meets previous criteria Initiator can use same time start/end points for both timers Submission Slide 10 Berger et al., Marvell
February, 2018 doc.: IEEE 802.11-18/0461r0 Motion We agree to measure MinToaReady and MaxToaAvailable starting from t4/t3 in the preceding sounding sequence to t1/t2 when receiving the new sounding sequence, see slide 10. Y: / N: / A: Submission Slide 11 Berger et al., Marvell
