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Ultra-Wideband Technology

Micro-Electronics Center Sharif University of Technology. UWB. Ultra-Wideband Technology. Ali Fotowat- Ahmady. Sharif University of Technology UWB Group: Ali Medi Hajir Hedayati Vahid Mir Moghtadaie Iman Khajenasiri. Micro-Electronics Center Sharif University of Technology.

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Ultra-Wideband Technology

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  1. Micro-Electronics Center Sharif University of Technology UWB Ultra-WidebandTechnology Ali Fotowat-Ahmady Sharif University of Technology UWB Group: Ali Medi HajirHedayati Vahid Mir Moghtadaie ImanKhajenasiri

  2. Micro-Electronics Center Sharif University of Technology UWB Outline • UWB Introduction • UWB Applications and Industries • Interference challenges in UWB systems and UWB Transmitter • UWB Receivers

  3. Micro-Electronics Center Sharif University of Technology UWB Introduction(Definition) • UWB transmitter signal BW: • Or, BW ≥ 500 MHz regardless of fractional BW fu-fl ≥0.20 ) fu+fl( Where: fu= upper 10 dB down point fl= lower 10 dB down point 2

  4. Micro-Electronics Center Sharif University of Technology UWB FCC Regulations 3.1 10.6 0.96

  5. UWB Signals Impulse Radio (IR) or narrow time-duration pulses multi-band orthogonal frequency-division multiplexing (MB-OFDM) Micro-Electronics Center Sharif University of Technology UWB

  6. High data rates communication and high-precision ranging applications High multipath and jamming immunity Extremely difficult to detect by unintended users Co-existence capability Low cost, low power and single chip architecture Micro-Electronics Center Sharif University of Technology UWB The key attributes of UWB technology

  7. Micro-Electronics Center Sharif University of Technology UWB Pulsed UWB applications Communications • Short/medium Range Communications Links Radar • Ground penetrating radars • Through wall radars • Imaging and ranging Intelligent Sensors • Telemetry • Motion Detectors • Intelligent Transport Systems • Next generation RFIDs Other • Medical Applications • Indoor localization (GPS assisted)

  8. Micro-Electronics Center Sharif University of Technology UWB FCC UWB Device Classifications • Report and Order authorizes 5 classes of devices with different limits for each: • Imaging Systems • Ground penetrating radars, wall imaging, medical imaging • Thru-wall Imaging & Surveillance Systems • Communication and Measurement Systems • Indoor Systems • Hand-held Systems • Vehicular Radar Systems • collision avoidance, improved airbag activation, suspension systems, etc • RTLS

  9. Micro-Electronics Center Sharif University of Technology UWB Security and Air force Applications • Preventing the air units from striking each other • Micro Air Vehicles (MAV), Each side 15 cm, for security operations

  10. Micro-Electronics Center Sharif University of Technology UWB Sensor Networks Applications • Un-Detectable Control of Borders and Gas &Oil pipelines • By using UWB Over Fiber (UOF), extending the range

  11. Micro-Electronics Center Sharif University of Technology UWB 4-UWB for Localization & Tracking • Medium Bit rate Long Communication Links (>100m) • Ranging/Localization in indoor/urban environments • Robust against jamming/detection

  12. Micro-Electronics Center Sharif University of Technology UWB Localization • Communications must be very robust and reliable as the positioning and the data transfer can be related to payment operations • Localisation / ticketing / logistics systems for control / safety / navigation in public environments and transportations

  13. Micro-Electronics Center Sharif University of Technology UWB Three Principles of Positioning • TOA (Time of Arrival) & RTD (Round Trip Delay) • TDOA (Time Difference of Arrival) • AOA (Angle of arrival)

  14. Micro-Electronics Center Sharif University of Technology UWB UWB RFID/ RLTS Technical Attributes There are seven key technical attributes that UWB RTLS offers the customer the ability to control their most critical business processes and high-value assets. • Small Tag Size Down to 1” x 1” x1” or smaller • Long Tag Life Up to 7+ years @ 1Hz Blink Rate • High Resolution/ Accuracy Real-time location accuracies of <1 ft with line of sight • High Tag Throughput Up to 5000+ tags/ second presence and 2500+ tags/ second locate (in a typical four receiver set-up) • High Tag Transmission Rate Up to 200 times/ second possible • Excellent Performance in Pulse response operates well in high multipath environments MetallicEnvironments • Long Range Up to 600+ ft line-of-sight with high-gain antenna presence and up to 300 ft between receivers locate

  15. Micro-Electronics Center Sharif University of Technology UWB UWB RFID Advantages • Communicationand Tracking at same time • Security • Simple and Low Cost tag

  16. XtremeSpectrum Time Domain General Atomics AetherWire & Location Multispectral Solutions (MSSI) Pulse-Link Appairent Technologies Pulsicom Staccato communications Intel TI Motorola Perimeter players Sony Fujitsu Philips Mitsubishi Broadcom Sharps Samsung Panasonic Micro-Electronics Center Sharif University of Technology UWB UWB RELATED INDUSTRIES

  17. Micro-Electronics Center Sharif University of Technology UWB Outline • Interference challenges in UWB systems • Conventional UWB pulses • Hermite and proposed UWB pulse • Proposed circuit for pulse implementation • Simulation results • Conclusion

  18. Micro-Electronics Center Sharif University of Technology UWB Possible interferers in UWB systems • Most significant interferer 802.11a (5GHz WLAN) • Avoiding 802.11a • MB-OFDM • Eliminating Band #2 • IR-UWB & DS-UWB • Using UWB lower Band • Using UWB upper Band

  19. Micro-Electronics Center Sharif University of Technology UWB Effects of Narrowband interferers on UWB system SNR (dB) of UWB in the presence of 802.11a interferer

  20. Micro-Electronics Center Sharif University of Technology UWB Effects of Narrowband interferers on UWB circuit • IR-UWB covering the whole band → the interferer is in-band → no pre-filtering → corrupted signal!! • Easier in MB-OFDM →the interferer is out of band → pre-filter • 2nd and 3rd order modulation of interferer • UWB receiver desensitization due to large interferer

  21. Micro-Electronics Center Sharif University of Technology UWB Effects of UWB on Narrowband system Data rate in the presence of UWB interferer SNR in the presence of UWB interferer

  22. Micro-Electronics Center Sharif University of Technology UWB Solution for In-Band interferers of IR-UWB Intended UWB pulse • IR-UWB, low power, low complexity compare with MB-OFDM • Of great interest • Covering the whole spectrum can be done by designing such a pulse featuring frequency nulls

  23. Micro-Electronics Center Sharif University of Technology UWB Applicable UWB pulses Time Domain Gaussian derived pulse : Frequency Domain(GHz) All Cosine Functions Without 5 GHz Cosine

  24. Micro-Electronics Center Sharif University of Technology UWB Modified Hermite Pulses • Hermite polynomials are the finite sum of terms like • To be orthogonal Modified Hermite pulse • Inherent nulls in the power spectrum of this pulse the main motivation behind this work • Complete Coexistence of UWB and the NB system located in the null

  25. Micro-Electronics Center Sharif University of Technology UWB 2nd order Modified Hermite Time Domain Frequency Domain(GHz) Modified Hermite Pulse Up-Converted One

  26. Micro-Electronics Center Sharif University of Technology UWB Designed Pulse Designed UWB Pulse The major problem is 5 GHz WLAN, 2nd order Hermit is OK! 2nd order Hermit pulse modified to be implementable in analog circuits

  27. Micro-Electronics Center Sharif University of Technology UWB Circuit Analysis • 6 blocks needed: • Square function • MOS device square law • Trans-linear circuits • Exponential function • Bipolar device • MOS device in sub-threshold region • Multiplier for mathematical multiplication • Mixer for up converting • VCO for cosine function • An input ramp stage

  28. Micro-Electronics Center Sharif University of Technology UWB Quadratic Function For a fully quadratic function two long channel MOS devices used, each switches in its cycle

  29. Micro-Electronics Center Sharif University of Technology UWB Overall Circuit

  30. Micro-Electronics Center Sharif University of Technology UWB Important parameters • The input DC biasing determines the current • R value chosen to keep MOS in saturation • The Cosine function determines the null frequency • The tuning circuit is placed for fine tuning due to process variation • The input ramp determines the BW of the pulse and the number of the nulls in the spectrum

  31. Micro-Electronics Center Sharif University of Technology UWB Simulation results Time domain response Frequency domain response FCC Indoor Mask

  32. Micro-Electronics Center Sharif University of Technology UWB Fine tuning of the nulls by the gain of the tuning circuit 20 dB gain increase of tuning circuit Tuning circuit normal gain Input ramp for both

  33. Micro-Electronics Center Sharif University of Technology UWB Pulse Characteristics

  34. Micro-Electronics Center Sharif University of Technology UWB Conclusion • The proposed UWB pulse features frequency nulls in the UWB spectrum • The pulse can be coarse or fine tuned by the input ramp voltage, frequency of the cosine function and gain of the tuning circuit • As a result no SNR degradation would occur for the NB system located in the null, and the NB system wouldn’t be disturbed

  35. Micro-Electronics Center Sharif University of Technology UWB Conclusion • No SNR degradation in UWB system will occur because of no overlapping with NB system • NB system in the null would be considered out of band and pre-filtering can be done without any loss of data • On chip filtering of the NB system can be done since the Q of the filter is relaxed due to the null existence • An IR-UWB transceiver covering the whole spectrum can be accomplished

  36. Micro-Electronics Center Sharif University of Technology UWB Future Works • Major UWB Limitation • Short distance communications • UWB over Fiber • UWB pulse design with notches in Optics

  37. Micro-Electronics Center Sharif University of Technology UWB New Design of UWB Receiver

  38. Micro-Electronics Center Sharif University of Technology UWB TX and RX Block Diagram • Main challenge in UWB is in Rx: • large bandwidth, • high required timing precision • difficult signal synchronization • Main difference of all RX topologies • Location of ADC ( in A , B or C in RX Block Diagram) • Matched filter correlation (coherent or incoherent) • Pulse template

  39. Micro-Electronics Center Sharif University of Technology UWB Receiver topologies • Fully digital (FD) • 4 bit : high power • 1 bit : low power but bad performance when interference • Transmitted reference (TR) • Energy detector(ED) • Data pulse as its own reference • Self-mixing of the noisy input signal • Impossible BPSK (PPM) • Flashing • high SNR • low interference environments • Quadrature Analog correlation (QAC)

  40. Micro-Electronics Center Sharif University of Technology UWB

  41. Micro-Electronics Center Sharif University of Technology UWB Flashing Receiver topology

  42. Micro-Electronics Center Sharif University of Technology UWB Quadrature Analog correlation (QAC) • Windowed sine wave as a template in matched filter to avoid complexity (Loss  1dB) • (Input)(LO)+(windowed integration) = Correlation with windowed sine wave( template) Quadrature Analog correlation receiver (QAC)

  43. Micro-Electronics Center Sharif University of Technology UWB Simulation Results • Bad performance of 1 bit FD in the strong interferer • increasing loss of the QAC in more dense multipath channels, due to its simplified channel compensation • the excellent performance of the QAC receiver in interference dominated environments

  44. Micro-Electronics Center Sharif University of Technology UWB • Comparison between Different Topologies • Figure of Merit: • “Energy/Useful Bit” or EPUB (the best parameter to tare-off between power and performance) Four channel models 1 path: LOS G: Gaussian Noise i: Interference QAC receiver has excellent EPUB.

  45. Micro-Electronics Center Sharif University of Technology UWB Implementation challenges • Template misalignment and clock offset • Low Sensitivity and jitter up to 300ps • Compensation of Clock offset by tracking the rotation of (I,Q) constellation vector in digital • IQ imbalance • up to 10 degree can be tolerated • Phase noise • out-of-band interferers to be mixed inside band • Dither around the ideal point in the constellation (noise for tracking loop) • ADC resolution

  46. Micro-Electronics Center Sharif University of Technology UWB Design Considerations • Flexibility in operation • Operation with a 0-960MHz and 3-5GHz front-end • Pulses with a bandwidth from 500MHz to 2GHz • Pulse period from 20nsec to 200nsec • PN code 1 to 63 pulses per bit(PG:0dB to 18dB) • Data-rates from 80kbps to 50Mbps • Operation phases • Acquisition Phase: Channel estimation, Synchronization , RX-TX Clock-offset estimation. • Detection Phase: detect the data, clock-offset and tracking

  47. Micro-Electronics Center Sharif University of Technology UWB Measurement Results • Implementation of QAC receiver in 0.18µm

  48. Micro-Electronics Center Sharif University of Technology UWB • Acquisition Phase • Search for the best window position • Search for the correct code phase for this window only • QAC in multipath • Performance loss in multipath channels • Loss Compensation by multi-window integration

  49. Micro-Electronics Center Sharif University of Technology UWB Communication andSub-cm Ranging

  50. Micro-Electronics Center Sharif University of Technology UWB Thanks for your attention

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