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UWB (Ultra Wideband) Communication System

UWB (Ultra Wideband) Communication System. 長庚電機通訊組 碩一 張晉銓 指導教授 : 黃文傑博士. Outline. Overview UWB Spectrum Single-Band and Multiband Spectral Keying™ Modulation Conclusion. Bluetooth, 802.11b Cordless Phones Microwave Ovens. 802.11a. Emitted Signal Power. PCS.

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UWB (Ultra Wideband) Communication System

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  1. UWB (Ultra Wideband) Communication System 長庚電機通訊組 碩一 張晉銓 指導教授:黃文傑博士

  2. Outline • Overview UWB Spectrum • Single-Band and Multiband • Spectral Keying™ Modulation • Conclusion

  3. Bluetooth, 802.11b Cordless Phones Microwave Ovens 802.11a Emitted Signal Power PCS “Part 15 Limit” -41 dBm/Mhz GPS UWB Spectrum 1.6 1.9 2.4 3.1 5 10.6 Frequency (Ghz) Overview UWB Spectrum 1/2 FCC ruling permits UWB spectrum overlay

  4. Overview UWB Spectrum 2/2 • High speed with low SNR (Shannon-Hartley law) Example: B = 7 GHz, SNR = 0.1, C = 0.96 GHz (UWB) B = 80 MHz, SNR = 103, C = 0.83 GHz (NB for music & VDO) • Lower power consumption than NB (100x lower) • Suitable for short-range wireless applications

  5. IEEE802.15.3a

  6. Single-Band and Multiband

  7. Single-Band and Multiband • Bandwidth and number of available band generate difference performance • Singleband is more sensitive to ISI generated by delay spread • Switching circuits problems • Low duty cycle allows power saving features • Minimizes collisions between colocated piconets??

  8. UWB Multi-Band Technology • UWB spectrum divided into multiple bands • One symbol will be composed of subpulses from multiple bands • Excellent performance in multipath • Scalability • Bit rate • Power consumption • Range • Complexity / Cost • Coexistence • IEEE 802.11a • Regulatory • Compliant with US FCC • Flexibility for world-wide regulatory action

  9. Multiband

  10. Multiband

  11. Spectral Keying™ Modulation UWB Symbol in Time • Transmit 2 or more subpulses using different bands • Order of bands defines symbol Voltage Time (ns)

  12. SK Definitions • Data encoded with • Sequence of bands in the pulse • Phase information on the subpulses

  13. Spectral Keying General Case • An SK symbol X, where can be defined in terms of the location in a MxT matrix, B and P • where • 0 means no transmission • ±1 allows Binary Phase Shift Keying (BPSK) • ± i allows Quadrature Phase Shift Keying (QPSK) • M is # of frequency bands • T is # of time slots • B is # of non-zero entries • P is # of polarity bits • N is # of available bits where For Optimum BER Performance in SK use M=T=B

  14. SK Rate Scalability Examples 2 bands no polarity 5 bands, with BPSK 8 bands with QPSK Sequence bits/sym. 1~6.5~15 Phase bits /sym. 0516 Total bits/sym. 111.531 For sequence bits, the set of allowable symbols increases with the factorial of the number of bands

  15. Multiband & Spectral Keying Multiband by QPSK Spectral Keying by BPSK

  16. Conclusions • A UWB system based on Spectral KeyingTM will meet or exceed all selection criteria • Spectral KeyingTM is a Multi-Band scheme • Good multipath performance • Flexibility in assigning bands for regulatory and interference avoidance • Unique high order modulation allows low symbol rate with long guard time between symbols • Minimizes ISI - At maximum data rate no equalizer needed • Off period is 75% at 13 MHz symbol rate - Allows power conservation • Efficient spectrum utilization allows frequency based channels • Provides scalability for power consumption, rate, range and complexity • Technology proven with demonstrations • Letter of assurance for essential patents submitted to the IEEE 802.15.3a leadership • The May 2003 presentation will focus on analysis and simulation

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