Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)

1. Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [A new ranging packet structure] Date Submitted: September, 2005] Source: [Yihong Qi, Huan-Bang Li, Shinsuke Hara and Ryuji Kohno, Company: National Institute of Information and Communications Technology ] Contact: Yihong Qi Voice:+81 46 847 5092, E-Mail: yhqi@nict.go.jp] Abstract: [A new ranging packet structure with a variable channel sounding length is devised. Its advantages include flexibility to accommodate a variety of ranging applications and limited complexity.] Purpose: [To propose a new ranging packet structure] 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.

2. A new ranging packet structure Yihong Qi, Huan-Bang Li, Shinsuke Hara and Ryuji Kohno National Institute of Information and Communications Technology (NICT)

3. Current ranging packet Preamble Header Payload Data on timing, crystal offset, etc Acquisition; channel sounding Control information

4. What is the problem? A variety of conflicting factorsimposed by various (potential) ranging applications, • Mobility • Update rate • On-air time • Ranging accuracy VS. Current solution (?): three preamble lengths, 50us, 500us and 4ms.

5. Motivation to our approach • Use a ``flexible” data length for channel sounding/ranging • Avoid elaborating on specifics for mobility, update rate… Let applications define their channel sounding lengths for ranging.

6. A new ranging packet ( type I) Multiplexing two (quasi-)orthogonal codes S1 and S2 Other modulation for data on timing, crystal offset, etc Ternary code S1 Ternary code S1 Preamble Header Payload header information modulated by S2 Point 2: Continue ranging/channel sounding by using S1 Point 1: Same preamble length as a communication packet or some basic lengths

7. A new ranging packet (type II) Only difference: Multiplexing two (quasi-)orthogonal codes S1 and S3 modulating real payload Multiplexing two (quasi-)orthogonal codes S1 and S2 Ternary code S1 Preamble Header Payload header information modulated by S2 Point 1: Same preamble length as a communication packet or some basic lengths Point 2: Continue ranging/channel sounding by using S1

8. New ranging packets in summary Note: S2 and S3 are selected from a different code set with S1

9. Features • Preamble length longer than that of a communication packet • Guarantee header information to be demodulated (understood) correctly • Flexible data length for channel sounding • Accommodate various factors such as ranging accuracy, mobile speed, update rate. • Multiplexing two (quasi-)orthogonal codes S1 and S2 in the header for a ``non-interruptive” channel sounding • S2 is used to modulate header information • S1 is for channel sounding • Multiplexing two (quasi-)orthogonal codes S1 and S3 in the payload • A compact ranging packet • Useful for applications involving mobility and frequent updates

10. Advantages • Flexible to a variety of requirements on ranging accuracy and applications • Avoiding specifications on update rate, ranging distance and mobility • Possible to adjust the channel sounding length in a real-time manner

11. Complexity and Non-coherent issues • Work with non-coherent receivers • Performance degraded as in a SOP scenario but in a controllable manner • Need multiple code correlators corresponding to codes S1, S2 and S3 • Same as the requirement of a regular ranging packet

12. Conclusions A new ranging packet structure • Flexible to accommodate various potential applications • With limited impact on non-coherent performance and complexity