Project: IEEE P Working Group for Wireless Personal Area Networks N

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1 Project: IEEE P802.5 Working Group for Wireless Personal Area Networks N (WPANs( WPANs) Title: [Two Hopeful Technologies for TG4a --- DS-UWB and CS-UWB] Date Submitted: [05, November, 2004] Source: [Huan-Bang Li, Kenichi Takizawa, Shigenobu Sasaki, Shinsuke Hara, Makoto Itami Tetsushi Ikegami, and Ryuji Kohno] Company [National Institute of Information and Communications Technology (NICT)] [lee@nict.go.jp] Re: [] Abstract [This document has been prepared for an official proposal in January Two possible technologies of direct-sequence UWB(DS-UWB) and chirp-signal UWB(CS-UWB) are investigated in performance on BER, ranging resolution, complexity, power consumption, SOP and so on. The performance comparison is concluded by a few differences in performance but we need to modify these primitive technologies so as to match with requirements. ] Purpose: [Providing technical contributions to IEEE a. ] Notice: This document has been prepared to assist the IEEE P 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 P Slide

2 Two Hopeful Technologies for TG4a --- DS-UWB and CS-UWB 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 Slide 2

3 Outline of presentation Requirements of TG4a DS-UWB and CS-UWB (Chirp signal UWB) Advantages of using DS-UWB and CS-UWB Correlation characteristics Coexistence Frequency bandwidth Link budget Performance examples Ranging issue Summary and comparison Conclusion Slide 3

4 Technical Requirements Low complexity, low cost, and low power consumption. Precision ranging by PHY --- tens of centimeters. Communication distance is ~30m (can be extended) Better robustness and mobility than Low bit rate (individual link) >= kbps. High bit rate (aggregated) >= Mbps. Slide 4

5 Advantages Both DS-UWB and CS-UWB are available for High precision ranging Be up to tens of centimeters Depend on pulse width (bandwidth) Low complexity Simple ADC (2 or 3-bit) High frequency efficiency Uniform use of frequency within the band. High robustness against noise and multipath Correlated processing Low power consumption Slide 5

6 Generation of CS-UWB CS-UWB can be generated by passing a pulse signal through a distributed delay line(ddl) such as a SAW DDL. Amplitude Frequency Amplitude Time Pulse signal Time Frequency Slide 6

7 Correlated processing Correlated processing produces not only high precision ranging but also robustness against noise and multipath. Correlated processing T B: 3- bandwidth of chirp T: time interval of chirp Correlator output Time shift[s] The wide the bandwidth, the sharp the peak. Slide 7

8 Characteristics of correlation DS-UWB CS-UWB autocorrelation cross correlation autocorrelation cross correlation cross correlation cross correlation cross correlation cross correlation Slide 8

9 Cross correlation coefficient DS-UWB CS-UWB Cross-correlation coefficient Slide 9

10 Coexistence Coexistence between DS-UWB and CS-UWB CS-UWB Down CHIRP DS-UWB pulse MF Frequency Slide 0

11 Robustness against multipath Multipath channel Due to the good correlation characteristics, correlator can detect a signal even under heavy multipath channel. Slide

12 Frequency Band We consider the use of UWB band here, and give examples of link budgets for use of the following two bandwidth. 2 BW=2 GHz (3.GHz 5.GHz) BW=500 MHz (3.GHz 3.6GHz) 2 3.G 3.6G 5.G Frequency Slide 2

13 DS-UWB Link Budget (BW=2GHz) Parameter Value Value Unit Parameter Value Value Notes Distance (d) 30 0 m Data rate (Rb) 024 (kbps) Peak payload bit rate (Rb) 024 kbps Modulation Coding rate (R) BPSK ½ Coherent detection (24,2)-Extended Golay Harddecision decoding Average Tx power (Pt) Tx antenna gain (Gt) Frequency Band Geometric center frequency (fc) m i GHz GHz Raw Symbol rate (Rs) Pulse duration (Tp) Rs=Rb/R (ksymbol/second) (ns) Path m (L) Path d m (Ld) Rx antenna gain (Gr) i Spreading code length (Ns) Chip rate (Rc) Chip duration =Rs*Ns (MHz) =/Rc (nsec) Rx power (Pr) Average noise power per bit (N) Rx Noise Figure (Nf) Average noise power per bit (Pn) m m m Minimum required Eb/N0 (S) 6.25 Implementation loss (I) 3.00 Link Margin Min. Rx Sensitivity Level m Slide 3

14 DS-UWB Link Budget (BW=500MHz) Parameter Data rate (Rb) Modulation Value Value 024 BPSK Notes (kbps) Coherent detection Parameter Distance (d) Peak payload bit rate (Rb) Average Tx power (Pt) Value Value Unit m kbps m Coding rate (R) Raw Symbol rate (Rs) Pulse duration (Tp) Spreading code length (Ns) ½ (24,2)-Extended Golay Harddecision decoding Rs=Rb/R (ksymbol/second) (ns) Tx antenna gain (Gt) Frequency band Geometric center frequency (fc) Path m (L) Path d m (Ld) Rx antenna gain (Gr) Rx power (Pr) i GHz GHz i m Chip rate (Rc) =Rs*Ns (MHz) Average noise power per bit (N) m Chip duration =/Rc (nsec) Rx Noise figure (Nf) 7.00 Average noise power per bit (Pn) m Minimum required Eb/N0 (S) 6.25 Implementation loss (I) 3.00 Link Margin Min. Rx Sensitivity Level m Slide 4

15 CS-UWB Link Budget (BW=2GHz) Parameter Data rate (Rb) Modulation Coding rate (R) Raw Symbol rate (Rs) Chirp signal duration (Tc) Spreading code length (Ns) Chip rate (Rc) Chip duration Value Value 024 BPSK ½ Notes (kbps) Coherent detection (24,2)-Extended Golay Harddecision decoding Rs=Rb/R (ksymbol/s) (ns) =Rs*Ns (MHz) =/Rc (nsec) Parameter Distance (d) Peak payload bit rate (Rb) Average Tx power (Pt) Tx antenna gain (Gt) Frequency band Geometric center frequency (fc) Path m (L) Path d m (Ld) Rx antenna gain (Gr) Rx power (Pr) Average noise power per bit (N) Rx Noise figure (Nf) Value Value Unit m kbps m i GHz GHz i m m Average noise power per bit (Pn) m Minimum required Eb/N0 (S) 6.25 Implementation loss (I) 3.50 Link Margin Min. Rx Sensitivity Level m Slide 5

16 CS-UWB Link Budget (BW=500MHz) Parameter Data rate (Rb) Modulation Value Value 024 BPSK Notes (kbps) Coherent detection Parameter Distance (d) Peak payload bit rate (Rb) Average Tx power (Pt) Value Value Unit m kbps m Coding rate (R) Raw Symbol rate (Rs) Chirp signal duration (Tc) Spreading code length (Ns) ½ (24,2)-Extended Golay Harddecision decoding Rs=Rb/R (ksymbol/s) (ns) Tx antenna gain (Gt) Frequency band Geometric center frequency (fc) Path m (L) Path d m (Ld) Rx antenna gain (Gr) Rx power (Pr) i GHz GHz i m Chip rate (Rc) =Rs*Ns (MHz) Average noise power per bit (N) m Chip duration =/Rc (nsec) Rx Noise figure (Nf) 7.00 Average noise power per bit (Pn) m Minimum required Eb/N0 (S) 6.25 Implementation loss (I) 3.50 Link Margin Min. Rx Sensitivity Level m Slide 6

17 Simulation results (Single link).0 One Packet includes 32 bytes. 0 - PER 0-2 CS-UWB BW=2GHz DS-UWB BW=2GHz CS-UWB BW=500MHz DS-UWB BW=500MHz Eb/N0 [] Slide 7

18 Simulation results (Single link) BER CS-UWB BW=2GHz DS-UWB BW=2GHz CS-UWB BW=500MHz DS-UWB BW=500MHz Eb/N0 [] Slide 8

19 Simulation block diagram for SOP Transmitter Receiver Transmitter 2 Receiver 2 Transmitter M Receiver M Slide 9

20 Simulation results for SOP 0-0 DS-UWB CS-UWB SNR=5 BER 0- SIR= SIR= Number of SOP Slide 20

21 Ranging issue Ranging precision depends on the frequency bandwidth used. Using a simple TOA, DS-UWB provides better precision than CS-UWB in principle. Slide 2

22 DS-UWB and CS-UWB Summary ++ good, + fair Low complexity Peak-toaverage ratio Effect of SOP DS-UWB CS-UWB Ranging precision ++ + Slide 22

23 Conclusions DS-UWB and CS-UWB are good candidates for 5.4a. Have similar characteristics and advantages. Present similar performances but have own strength at different aspects. Can be further improved Both can meet the Technical Requirements. Low complexity, low cost, low power consumption. Precision ranging. Robustness. More studies are on going and will be presented at January meeting. Slide 23