1. Submission doc.: IEEE 11-11-1564-00-00ahr0 November 2011 Klaus Doppler, NokiaSlide 1 Sequence design for parallel ACK Date: 2011-09-15 Authors:

2. Submission doc.: IEEE 11-11-1564-00-00ahr0 November 2011 Klaus Doppler, NokiaSlide 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

3. Submission doc.: IEEE 11-11-1564-00-00ahr0 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 Slide 3Klaus Doppler, Nokia November 2011 SIFS Probe AP STA1 ACK STA2 ACK STA3 STA4 ACK Pull SIFS have data to send

4. Submission doc.: IEEE 11-11-1564-00-00ahr0 Parallel ACKs Parallel ACKs are separated in code-domain Sequence ID identifies STA ID Slide 4Klaus Doppler, Nokia November 2011 Time for ACK frame Sequence 1 (STA 1) Sequence 2 (STA 2) Sequence 3 (STA 3) Sequence 4 (STA 4) Code-domain

5. Submission doc.: IEEE 11-11-1564-00-00ahr0 Sequence for STA Identification (1/2) Slide 5Klaus Doppler, Nokia November 2011 root of sequence integer length of sequence Cyclic shift by k

6. Submission doc.: IEEE 11-11-1564-00-00ahr0 Sequence for STA Identification (2/2) Slide 6Klaus Doppler, Nokia November 2011

7. Submission doc.: IEEE 11-11-1564-00-00ahr0 (a) Map a part of ZC sequence to OFDM subcarriers Meet spectrum mask Take advantage of existing OFDM structure DFT (or IDFT) of ZC sequence has unit amplitude ̶ Limits PAPR and bounds interference to other STAs Parallel ACK Transmission Slide 7Klaus Doppler, Nokia November 2011 PART 1PART 2…PART 8 ZC sequence for STA1 … ACK PART 1PART 2…PART 8 STA1 STA2 ZC sequence for STA2 CPpart 1 CPpart 1 (a) (b) CPpart 8 CPpart 8 (a) (b) (a) (b) … (b) IFFT and add cyclic prefix (CP) ACK_STA1 ACK_STA2 Parallel ACKs to AP

8. Submission doc.: IEEE 11-11-1564-00-00ahr0 Parallel ACK Reception Slide 8Klaus Doppler, Nokia November 2011 AP ACK_STA1 + ACK_STA2 T FFT T RTT : max round-trip timeT MD : max. multipath delay T CP T RTT T MD T CP : CP duration T CP CP part 1 CP part 2 CP part 1 CP part 2 … … ACK_STA1 ACK_STA2

9. Submission doc.: IEEE 11-11-1564-00-00ahr0 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 limited scenario (i.e., there are multiple STAs sending ACKs), channel estimation is challenging Slide 9Klaus Doppler, Nokia November 2011

10. Submission doc.: IEEE 11-11-1564-00-00ahr0 Simulation Setup Slide 10Klaus Doppler, Nokia November 2011 Channel Bandwidth2MHz Channel modelSCM Urban Macro [2] FFT Size/Number of Subcarriers64/56 IFFT/FFT Period32us/32us Max Propagation Delay6us (1km range) Cyclic Prefix Duration12us (> 6us + 2us) OFDM Symbol Duration44us (12us + 32us) ACK Frame Duration (8 OFDM SYMs)352us Max Number of Sequences64 64 ZC sequences Length of seq. Root indexAmount of cyclic shifts Nzc=443 q=230 0 13 26 39 52 65 78 91 104 117 130 143 156 169 182 195 208 221 234 247 260 273 286 299 312 325 338 351 364 377 q=280 0 13 26 39 52 65 78 91 104 117 130 143 156 169 182 195 208 221 234 247 260 273 286 299 312 325 338 351 364 377 390 403 416 429

11. Submission doc.: IEEE 11-11-1564-00-00ahr0 Simulation Results Slide 11Klaus Doppler, Nokia November 2011

12. Submission doc.: IEEE 11-11-1564-00-00ahr0November 2011 Klaus Doppler, NokiaSlide 12 References [1] PP MAC contribution [2] J. Salo et al, “3GPP Spatial Channel Model,” [Online] Available: http://www.tkk.fi/Units/Radio/scm/

13. Submission doc.: IEEE 11-11-1564-00-00ahr0Month Year John Doe, Some CompanySlide 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

14. Submission doc.: IEEE 11-11-1564-00-00ahr0Month Year John Doe, Some CompanySlide 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.

15. Submission doc.: IEEE 11-11-1564-00-00ahr0Month Year John Doe, Some CompanySlide 15 802.11 Template Instructions 3/4 PowerPoint Submission Preparation Summary: –Things to do:7 –Fields to fill in:12

16. Submission doc.: IEEE 11-11-1564-00-00ahr0Month Year John Doe, Some CompanySlide 16 802.11 Template Instructions 4/4 Recommendations –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

17. Submission doc.: IEEE 11-11-1564-00-00ahr0Month Year John Doe, Some CompanySlide 17 [begin placing presentation body text here]

18. Submission doc.: IEEE 11-11-1564-00-00ahr0Month Year John Doe, Some CompanySlide 18