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Sequence design for parallel ACK

Sequence design for parallel ACK. Authors:. Date: 2011-09-15. Abstract. Parallel ACK is crucial to the success of Probe and Pull MAC This presentation gives more details on the parallel ACK design for 802.11ah. Parallel ACK Mechanism [1].

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Sequence design for parallel ACK

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  1. Sequence design for parallel ACK Authors: • Date: 2011-09-15 Klaus Doppler, Nokia

  2. Abstract • Parallel ACK is crucial to the success of Probe and Pull MAC • This presentation gives more details on the parallel ACK design for 802.11ah Klaus Doppler, Nokia

  3. Parallel ACK Mechanism [1] • STAs having data to send transmits ACKs concurrently (in time-aligned manner) • Detection at AP impaired by parallel ACKs Need methods for resolving parallel ACKs SIFS SIFS Pull Probe AP ACK STA1 have data to send ACK STA2 have data to send STA3 ACK STA4 have data to send Klaus Doppler, Nokia

  4. Parallel ACKs • Parallel ACKs are separated in code-domain • Sequence ID identifies STA ID Time for ACK frame Code-domain Klaus Doppler, Nokia

  5. Sequence for STA Identification (1/2) • Zadoff-Chu sequence , • Properties • Zero cyclic autocorrelation • Minimum cyclic cross-correlation • If is relative prime with , root of sequence integer length of sequence Cyclic shift by k • If is prime, the condition is guaranteed Klaus Doppler, Nokia

  6. Sequence for STA Identification (2/2) • Zero cyclic autocorrelation implies • Cyclic shifts of , i.e., are orthogonal for • Maximum orthogonal ZC sequences from a single root • Minimum cyclic cross-correlation implies • If , cyclic cross-correlation between and , where and , has • Root values and amount of cyclic shifts characterize STA ID Klaus Doppler, Nokia

  7. Parallel ACK Transmission • Take advantage of existing OFDM structure • DFT (or IDFT) of ZC sequence has unit amplitude • Limits PAPR and bounds interference to other STAs ZC sequence for STA1 STA1 ZC sequence for STA2 (a) Map a part of ZC sequence to OFDM subcarriers Meet spectrum mask STA2 (a) (a) (a) (b) IFFT and add cyclic prefix (CP) (b) (b) (b) … ACK_STA1 … Parallel ACKs to AP ACK_STA2 Klaus Doppler, Nokia

  8. Parallel ACK Reception • Sum of ACK packets arrives at AP with delays • , e.g., for sensors in 1km range for urban macro (SCM [2]) AP ACK_STA1 +ACK_STA2 TMD TFFT TFFT … ACK_STA1 … TRTT ACK_STA2 TCP TCP TCP: CP duration TRTT: max round-trip time TMD: max. multipath delay Klaus Doppler, Nokia

  9. Parallel ACK Detection • Active user identification • Joint detection of the number of active users and their identities • Asynchronous detection • Packet arrival with delays (maximum delay with 6us) • Non-coherent detection • In interference limitedscenario (i.e., there are multiple STAs sending ACKs), channel estimation is challenging Klaus Doppler, Nokia

  10. Simulation Setup Klaus Doppler, Nokia

  11. Simulation Results Klaus Doppler, Nokia

  12. References • [1] PP MAC contribution • [2] J. Salo et al, “3GPP Spatial Channel Model,” [Online] Available: http://www.tkk.fi/Units/Radio/scm/ Klaus Doppler, Nokia

  13. 802.11 Template Instructions 1/4 • To properly identify your PowerPoint presentation as an IEEE 802.11 Submission there are 7 steps that you must complete, and 12 data fields that you must fill in. • Step 1. Obtain a document number (has the form yy/xxxx). • Step 2. Title slide: Fill in the presentation subject title text, the full date (in ISO 8601 format of YYYY-MM-DD), and the complete author(s) details (a total of 3 data fields). • Step 3. Abstract slide: Fill in the abstract text. • Step 4. Press “Office” button, Prepare / Properties. Fill in the 2 data fields: • Author field = first author's name • Title field = Title of presentation John Doe, Some Company

  14. 802.11 Template Instructions 2/4 • Step 5. Menu select View, Master, Slide Master, select the top master page (theme slide master). Place the document designator in the right hand side of the header. • Document designator example "doc.: IEEE 802.11-04/9876r0" , or • "doc.: IEEE 802.11-04/9876r2" • Step 6. Menu select Insert, Header and Footer (5 data fields): • Slide tab: • Date & Time, Fixed = venue date (as Month Year, e.g. January 2005) • Footer = first author, company • Notes tab: • Data and time, Fixed = venue date (as Month Year, e.g. January 2005) • Header = document designator (e.g. “doc.: IEEE 802.11-04/9876r0”) • Footer = first author, company • Click "Apply to all". • Step 7. Delete the four template instruction slides. John Doe, Some Company

  15. 802.11 Template Instructions 3/4 • PowerPoint Submission Preparation Summary: • Things to do: 7 • Fields to fill in: 12 John Doe, Some Company

  16. 802.11 Template Instructions 4/4Recommendations • a) Always create a new presentation using the template, rather than using someone else's presentation. • b) For quick and easy creation of new 802.11 submissions, place the 802.11 template files in the template folder area on your computer. Typical locations are: • c:\Program Files\Microsoft Office\Templates\802.11, or • c:\Documents and Settings\User Name\Application Data\Microsoft\Templates\802.11 • To create a new submission from within PowerPoint, menu select File, New, then select the appropriate 802.11 template file. • c) When you update or revise your presentation, remember to check all 6 fields in steps 5 and 6 for the correct values. • rev: 2010-03-01 John Doe, Some Company

  17. [begin placing presentation body text here] John Doe, Some Company

  18. John Doe, Some Company

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