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: [Chirp SignalingUWB scheme] Date Submitted: [January 2005] Source: [Huan-Bang Li(1), Kenichi Takizawa(1), Shigenobu Sasaki(1), Shinsuke Hara(1), Makoto Itami(1), Tetsushi Ikegami(1), Ryuji Kohno(1), Toshiaki Sakane(2), Kiyohito Tokuda(3)] Company [(1)National Institute of Information and Communications Technology (NICT), (2)Fujitsu Limited, (3)Oki Electric Industry Co., Ltd.] E-Mail: ［lee@nict.go.jp] Re: [Optional mode on TG4a UWB-PHY baseline] Abstract [This document describes chirp-signal UWB(CS-UWB), which is one of the optional mode on the UWB-PHY baseline for TG4a. ] Purpose: [Providing technical contributions for standardization by IEEE 802.15.4a. ] 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. Li, Takizawa, Sasaki, Hara, Itami, Ikegami, Kohno, NICT

2. Chirp Signaling UWB Scheme Huan-Bang Li, Kenichi Takizawa,Shigenobu Sasaki, Shinsuke Hara, Makoto Itami, Tetsushi Ikegami, and Ryuji Kohno National Institute of Information and Communications Technology (NICT), Japan Toshiaki Sakane Fujitsu Limited, Kiyohito Tokuda Oki Electric Industry Co. Ltd. Li, Takizawa, Sasaki, Hara, Itami, Ikegami, Kohno, NICT

3. Outlines • Introduction of chirp signaling UWB. • Technical advantages • Link budget examples • Performance examples on SOP • Concluding remarks Reference: 15-04-0648-02-004a 15-04-0716-01-004a Li, Takizawa, Sasaki, Hara, Itami, Ikegami, Kohno, NICT

4. Benefits of chirp signaling (CS) UWB • Additional dimension for SOP • Chirp slop and/or chirp pattern • Available to be combined with DS-code and/or frequency subbands • Low Peak-to-average ratio • Efficient use of FCC spectrum mask • Less interference level, better coexistence. • Enhancement of robustness against multipath • Better autocorrelation than DS-UWB. • Potential ability to increase ranging precision • Benefit from excellent autocorrelation Li, Takizawa, Sasaki, Hara, Itami, Ikegami, Kohno, NICT

5. Generation of CS-UWB • CS-UWB can be generated by passing a pulsesignal through a distributed delay line（DDL） such as a SAW DDL. Frequency Time DDL Amplitude Amplitude Time Pulse signal Frequency Li, Takizawa, Sasaki, Hara, Itami, Ikegami, Kohno, NICT

6. Correlated processing • Correlated processing produces not only high precision ranging but also robustness against noise and multipath. Correlated processing Correlator output B: 3-dB bandwidth of chirp T: time interval of chirp Time shift[s] The wide the bandwidth, the sharp the peak. Li, Takizawa, Sasaki, Hara, Itami, Ikegami, Kohno, NICT

7. Correlation characteristics DS-UWB Chirp Signal Auto-correlation Cross-correlation Auto-correlation Cross-correlation Cross-correlation Cross-correlation Cross-correlation Cross-correlation Li, Takizawa, Sasaki, Hara, Itami, Ikegami, Kohno, NICT

8. Cross correlation coefficient DS-UWB CS-UWB Li, Takizawa, Sasaki, Hara, Itami, Ikegami, Kohno, NICT

9. Robustness against multipath and interference DDL channel Due to the excellent correlation characteristics, correlator can detect a signal even under heavy multipath and interference channel. Li, Takizawa, Sasaki, Hara, Itami, Ikegami, Kohno, NICT

10. Overall Block Diagram With Optional CS Transmitter Comm.data BW = 500MHz or 2GHz Spreading Pulse shaping CHIRP GA Coding & modulation Ranging data Local oscillator Receiver Pre-Select Filter Decision/ FEC decoder LPF GA 1 or 2-bit ADC Comm.data LNA De- CHIRP GA LPF 1 or 2-bit ADC Ranging data I Local oscillator Peak detection Sync. Ranging processing Q Time base Calculation Additional circuits to DS-UWB as an option Li, Takizawa, Sasaki, Hara, Itami, Ikegami, Kohno, NICT

11. linear-chirp linear-chirp linear-chirp linear-chirp linear-chirp time Waveforms With & Without Optional CS Gaussian pulse Gaussian pulse Gaussian pulse Gaussian pulse Gaussian pulse time Coding & modulation Spreading Pulse shaping CHIRP GA Local oscillator Li, Takizawa, Sasaki, Hara, Itami, Ikegami, Kohno, NICT

12. DS-UWB Link Budget (BW=500MHz) Li, Takizawa, Sasaki, Hara, Itami, Ikegami, Kohno, NICT

13. CS-UWB Link Budget (BW=500MHz) The items given in red characters have different values from those of DS Due to the low peak-to-average ratio, CS-UWB provides 1 dB additional link margins. Li, Takizawa, Sasaki, Hara, Itami, Ikegami, Kohno, NICT

14. CS-UWB BW=2GHz DS-UWB BW=2GHz CS-UWB BW=500MHz DS-UWB BW=500MHz 1.0 10-1 10-2 10-3 PER 2 3 4 5 6 7 8 Eb/N0 [dB] Simulation results (Single link) One Packet includes 32 bytes. Li, Takizawa, Sasaki, Hara, Itami, Ikegami, Kohno, NICT

15. Multiple Access Methods For SOP • FDM (frequency subbands) • Number is limited. • CDM (different code sequences) • Possible codes reduced if we seek short length codes. • Chirped pulses (in option): • Plenty of source !(chirp slope and pattern) • Better performance than CDM ! Li, Takizawa, Sasaki, Hara, Itami, Ikegami, Kohno, NICT

16. Simulation block diagram for SOP Desired transmitter Pc Channel Pi Undesired transmitter A Channel Receiver Devices of Other piconets Undesired transmitter B Pi Channel Undesired transmitter C Pi Channel Devices in the same piconet Li, Takizawa, Sasaki, Hara, Itami, Ikegami, Kohno, NICT

17. Simulation results for SOP Li, Takizawa, Sasaki, Hara, Itami, Ikegami, Kohno, NICT

18. Scalability With PN Sequences Li, Takizawa, Sasaki, Hara, Itami, Ikegami, Kohno, NICT

19. Conclusion remarks • High capacity for SOP • Plenty of source with chirp • Combination with FDM and/or CDM • Additional link margins • Low peak-to-average ratio. • Robustness against interference and multipath • Excellent correlation characteristics • Potential high precision ranging. • Excellent correlation characteristics • An selectivity for FFD and RFD • Chirp vs. Non chirp Li, Takizawa, Sasaki, Hara, Itami, Ikegami, Kohno, NICT