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: [Impulse Radio Signaling for Communication and Ranging] Date Submitted: [25 April 2005] Source: [Francois Chin] Company: [Institute for Infocomm Research, Singapore] Address: [21 Heng Mui Keng Terrace, Singapore 119613] Voice: [65-68745687] FAX: [65-67744990] E-Mail: [chinfrancois@i2r.a-star.edu.sg] Re: [] Abstract: [Presents signaling options to achieve precision ranging with both coherent and non-coherent receivers] Purpose: [To discuss which signal waveform would be the most feasible in terms of performance and implementation trade-offs] 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. Francois Chin (I2R)

2. Objectives • PRF definition • Impulse Radio Signaling Proposal • System Parameters (500+ MHz and 1500+ MHz Bands) • Receiver Code Sequences Francois Chin (I2R)

3. PRI VPeak TC PRF: Definition • Pulse repetition frequency (PRF): Number of pulses occurring in 1 s. • Pulse repetition interval (PRI): Time from the beginning of one pulse to the beginning of the next. Francois Chin (I2R)

4. PRF Definition : Example Pulse Repetition Interval 1 2 3 4 5 6 7 8 N-1 N ………………………… Non-inverted pulses are blue, Inverted pulses are green. …………………………................. Quiet time Active time Symbol Interval Francois Chin (I2R)

5. Minimum PRF Requirements Francois Chin (I2R)

6. Frequency Plan Band No. 4 1 2 3 3 4 5 GHz 3.25 3.5 3.75 4.25 4.5 4.75 Francois Chin (I2R)

7. Main Features of proposed system Proposal main features: • Impulse-radio based (pulse-shape independent) • Common synchronisation / ranging preamble signaling for different classes of nodes / type of receivers (coherent / differential / noncoherent) • Band Plan based on multiple 500 MHz bands (center band mandatory) and optional wider bandwidth (1.5 GHz+) concentric with center band • Robustness against SOP interference • Robustness against other in-band interference • Scalability to trade-off complexity/performance Francois Chin (I2R)

8. Types of Receivers Supported • Coherent Detection: The phase of the received carrier waveform is known, and utilized for demodulation • Differential Chip Detection: The carrier phase of the previous signaling interval is used as phase reference for demodulation • Non-coherent Detection: The carrier phase information (e.g.pulse polarity) is unknown at the receiver Francois Chin (I2R)

9. Proposed System Parameters (528 MHz) Francois Chin (I2R)

10. Criteria of Code Sequence Design • The sequence Set should have orthogonal (or near orthogonal) cross correlation properties to minimise symbol decision error for all the below receivers • For coherent receiver • For differential chip receiver • For non-coherent symbol detection receiver • Energy detection receiver • Each sequence should have good auto-correlation properties Francois Chin (I2R)

11. Base Sequence Set • 31-chip Ternary Sequence set are chosen • Only one sequence and one fixed band (no hopping) will be used by all devices in a piconet • Logical channels for support of multiple piconets • 6 sequences = 6 logical channels (e.g. overlapping piconets) for each FDM Band • The same base sequence will be used to construct the symbol-to-chip mapping table Francois Chin (I2R)

12. Symbol-to-Chip Mapping: Gray 4-ary Ternary Orthogonal Keying Base Sequence #1 Francois Chin (I2R)

13. Good Properties of the Mapping Sequence • Cyclic nature, leads to simple implementation • Zero DC for each sequence • No need for carrier phase tracking (i.e. coherent receiver) • The same code sequence will be used for synchronisation, ranging, SOP interference suppression Francois Chin (I2R)

14. Transmission Mode Francois Chin (I2R)

15. Modulation & Coding (Mode 1) Binary data From PPDU Symbol- to-Chip Bit-to- Symbol Zero Padding Symbol Repetition Pulse Generator Bit to symbol mapping: group every 4 bits into a symbol Symbol-to-chip mapping: Each 4-bit symbol is mapped to one of 16 32-chip sequence, according to 4-ary Ternary Orthogonal Keying Zero Padding: suggested 9 PRI for reducing inter-symbol interference Symbol Repetition: for data rate and range scalability Pulse Genarator: • Transmit Ternary pulses at PRF = 33MHz {0,1,-1} Ternary Sequence Francois Chin (I2R)

16. Symbol Mapping for Mode 1: Ternary Orthogonal Keying + Zero Padding Base Sequence #1 Zero Padding Francois Chin (I2R)

17. Modulation & Coding (Mode 2) Binary data From PPDU Symbol- to-Chip Ternary- Binary Bit-to- Symbol Zero Padding Symbol Repetition Pulse Generator Bit to symbol mapping: group every 4 bits into a symbol Symbol-to-chip mapping: Each 4-bit symbol is mapped to one of 16 32-chip sequence, according to 4-ary Ternary Orthogonal Keying Ternary to Binary conversion: (-1/+1 → 1,0 → -1) Zero Padding: suggested 9 PRI for reducing inter-symbol interference Symbol Repetition: for data rate and range scalability Pulse Genarator: • Transmit bipolar pulses at PRF = 33MHz {1,-1} Binary Sequence {0,1,-1} Ternary Sequence Francois Chin (I2R)

18. Binary Base Sequences (after Ternary – Binary Conversion) This is in fact m-Sequences! Francois Chin (I2R)

19. Symbol Mapping for Mode 2: Binary Orthogonal Keying + Zero Padding (after Ternary – Binary Conversion) Binary Base Sequence #1 Zero Padding Francois Chin (I2R)

20. Binary Signaling for Symbol ’00’ Pulse Repetition Interval ~ 30ns 1 2 3 4 5 6 7 8 30 31 ………………………… Non-inverted pulses are blue, Inverted pulses are green. …………………………................. Quiet time ~272ns Active time ~940ns Symbol Interval ~1.212us Francois Chin (I2R)

21. Synchronisation Preamble Correlator output for synchronisation • Code sequences has good autocorrelation properties • Synchronisation / Ranging Preamble is constructed by repeating ‘00’ symbols • Long preamble is constructed by further symbol repetition Francois Chin (I2R)

22. Code Sequences for different Receiver Francois Chin (I2R)

23. Code Sequence Properties & Performance • AWGN Performance • Multipath Performance • For Coherent Symbol Detector • For Non-coherent Symbol Detector • For Differential Chip Detector • For Energy Detector To be included in future revision Francois Chin (I2R)

24. Proposed Optional Wider Band System Francois Chin (I2R)

25. Summary The proposed Impulse-radio based system: • has common ternary signaling that • Can be received simultaneously by different types of receivers, namely coherent, differential, and energy detectors • Can be used for both synchronisation and ranging simultaneously • Is robust against SOP interference Francois Chin (I2R)