doc.: IEEE 802. 15-10-0095-01-004f

1. February 2010 • doc.: IEEE 802. 15-10-0095-01-004f Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [Time Domain UWB SFD Proposal] Date Submitted: [19 February, 2010] Source: [Adrian Jennings] Company [Time Domain] Address [330 Wynn Drive, Suite 300, Huntsville, AL. 35805. USA] Voice:[+1 256 759 4708], FAX: [+1 256 922 0387], E-Mail:[adrian.jennings@timedomain.com] Re: [Proposal for robust SFD for UWB RFID PHY] Abstract: [Proposal describing a length 16 SFD which is very robust against bit errors in the preamble and SFD] Purpose: [To resolve one of the TBDs in the merged IEEE 802.15.4f merged proposal] 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. Submission Adrian Jennings, Time Domain

2. February 2010 • doc.: IEEE 802. 15-10-0095-01-004f Time Domain UWB SFD Proposal • Adrian Jennings • adrian.jennings@timedomain.com • +1 256 759 4708 Submission Adrian Jennings, Time Domain

3. February 2010 • doc.: IEEE 802. 15-10-0095-01-004f Introduction • This document describes a Sync Frame Delimiter (SFD) for consideration as the SFD for the IEEE 802.15.4f UWB RFID PHY • The proposed SFD is very robust against bit errors in both the preamble and the SFD • Excellent pulse alignment characteristics • High performance in the presence of an all 1’s preamble Submission Adrian Jennings, Time Domain

4. February 2010 • doc.: IEEE 802. 15-10-0095-01-004f Proposed SFD 0001 0100 1001 1101 Submission Adrian Jennings, Time Domain

5. February 2010 • doc.: IEEE 802. 15-10-0095-01-004f Simulation Rationale • All possible SFDs from length 11 to length 16 were evaluated • Each was appended to a preamble sequence of all 1’s as already agreed • 0, 1 and 2 bit errors were permutated through all bit positions in the preamble and SFD • The pattern with errors was correlated against the SFD template and evaluated • The performance metric used for evaluation was: Difference in amplitude between the main autocorrelation peak, and the worst case sidelobe (“MinDistance”) Submission Adrian Jennings, Time Domain

6. February 2010 • doc.: IEEE 802. 15-10-0095-01-004f Simulation Results: 2 Bit Errors • The best performing codes had the following MinDistance scores for the 2 bit error cases: • Multiple codes in each length category achieved these MinDistance scores Submission Adrian Jennings, Time Domain

7. February 2010 • doc.: IEEE 802. 15-10-0095-01-004f Simulation Results: No Bit Errors • The 16 length codes with MinDistance of 10 with 2 bit errors have the following 0 error performance 0001 0100 1001 1101 Submission Adrian Jennings, Time Domain

8. February 2010 • doc.: IEEE 802. 15-10-0095-01-004f Summary • The 0001 0100 1001 1101 code has the best properties when appended to an all 1’s preamble • Best zero error autocorrelation (MinDistance = 18) • Best 2 bit error autocorrelation (MinDistance = 10) Submission Adrian Jennings, Time Domain

9. February 2010 • doc.: IEEE 802. 15-10-0095-01-004f Further SFD Analysis • Further analysis was required after reviewing documents • IEEE 802. 15-10-0095-00-004f • IEEE 802. 15-10-0105-00-004f • Analysis performed: • Evaluation of Decawave SFD in the presence of bit errors • Comparison of two different correlation techniques • Examine all SFD bits • Examine only 0 positions in SFD • Results are presented for discussion Submission Adrian Jennings, Time Domain

10. The 0101 1101 1011 0001 pattern is not robust in the presence of bit errors February 2010 • doc.: IEEE 802. 15-10-0095-01-004f Decawave SFD With Bit Errors Charts show histogram of MinDistance as a function of bit error positions Submission Adrian Jennings, Time Domain

11. February 2010 • doc.: IEEE 802. 15-10-0095-01-004f Comparison of Correlation Techniques • Time Domain thesis: • It is important to examine all SFD bit positions for best performance • Decawave thesis: • With an all 1’s preamble, only the SFD 0 positions need to be examined • Discussion • Decawave thesis is true when distinguishing SFD from preamble (i.e. end of preamble detection) • Time Domain thesis is true when distinguishing SFD from out of phase SFD (i.e. alignment) Submission Adrian Jennings, Time Domain

12. Examining only 0 positions if SFD does not provide the best alignment performance February 2010 • doc.: IEEE 802. 15-10-0095-01-004f Two Correlation Methods: SFD + Preamble Submission Adrian Jennings, Time Domain

13. Examining only 0 positions if SFD does not provide the best alignment performance February 2010 • doc.: IEEE 802. 15-10-0095-01-004f Two Correlation Methods: SFD Only Submission Adrian Jennings, Time Domain

14. February 2010 • doc.: IEEE 802. 15-10-0095-01-004f Discussion • The Time Domain proposed pattern of 0001 0100 1001 1101 provides excellent alignment properties even in the presence of bit errors • The Decawave proposed pattern of 0101 1101 1011 0001 has better performance in some respects, but is not robust against bit errors and does not provide the best alignment performance • Is there a third SFD that results from an amalgamation of the full set of evaluation criteria? • Or is 0001 0100 1001 1101 a good solution that we can agree on? Submission Adrian Jennings, Time Domain