ULTRA WIDE BAND TECHNOLOGY

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ULTRA WIDE BAND TECHNOLOGY
BODY AREA NETWORKS
BW ³ 500 MHz regardless of fractional BW

UWB is a form of extremely wide spread spectrum where RF energy is spread over gigahertz of spectrum
Wider than any narrowband system by orders of magnitude
Power seen by a narrowband system is a fraction of the total UWB power
UWB signals can be designed to look like imperceptible random noise to conventional radios

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ULTRA WIDE BAND TECHNOLOGY

  1. 1. Low Power UWB Technology for WBAN
  2. 2. 2 What is Ultra Wide Band ? • UWB transmitter signal BW: ‘OR’ • BW ≥ 500 MHz regardless of fractional BW fu-fl fu+fl 2 ≥ 0.20 Where: fu= upper 10 dB down point fl = lower 10 dB down point Source: US 47 CFR Part15 Ultra-Wideband Operations FCC Report and Order, 22 April 2002: http://www.fcc.gov/Bureaus/Engineering_Technology/Orders/2002/fcc02048.pdf
  3. 3. UWB: Large Fractional Bandwidth PowerSpectralDensity(dB) one “chip”one “chip” CDMA: 1.288Mcps/1.8 GHz 0.07% bandwidth 6% bandwidth -80 -40 0 Frequency (GHz) 3 6 9 12 15 Random noise signal 100% bandwidth UWBUWB NBNB 20% bandwidth
  4. 4. Relative Bandwidth • UWB is a form of extremely wide spread spectrum where RF energy is spread over gigahertz of spectrum – Wider than any narrowband system by orders of magnitude – Power seen by a narrowband system is a fraction of the total UWB power – UWB signals can be designed to look like imperceptible Narrowband (30kHz) Wideband CDMA (5 MHz) UWB (Several GHz) Frequency Part 15 Limit ( -41.3dBm/Hz )
  5. 5. UWB Signal Characteristics 7,500 MHz available spectrum for unlicensed use US operating frequency: 3,100 – 10,600 MHz Emission limit: -41.3dBm/MHz EIRP Indoor and handheld systems UWB signal transmitter defined as having the lesser of Fractional bandwidth greater than 20% Occupies more than 500 MHz UWB is NOT defined in terms of Modulation or Carrierless or Impulse radio
  6. 6. FCC First Report and Order Authorizes Five Types of Devices Class / Application Frequency Band for Operation at Part 15 Limits User Limitations Communications and Measurement Systems 3.1 to 10.6 GHz (different “out-of-band” emission limits for indoor and hand-held devices) No Imaging: Ground Penetrating Radar, Wall, Medical Imaging <960 MHz or 3.1 to 10.6 GHz Yes Imaging: Through-wall <960 MHz or 1.99 to 10.6 GHz Yes Imaging: Surveillance 1.99 to 10.6 GHz Yes Vehicular 22 to 29 GHz No
  7. 7. Effectiveness of Ultra Wide Band • Shannon showed that the system capacity, C, of a channel perturbed by AWGN --- )1(log2 N S BC += Where: C = Max Channel Capacity (bits/sec) B = Channel Bandwidth (Hz) S = Signal Power (watts) N = Noise Power (watts) Capacity per channel (bps) ∝ B Capacity per channel (bps) ∝ log(1+S/N) 1. Increase B 2. Increase S/N, use higher order modulation 3. Increase number of channels using spatial separation (e.g., MIMO) What if I do not require a high capacity ?
  8. 8. UWB -5db 5 db 10 db 15 db 1 2 3 4 1/2 1/4 1/8 1/16 Bits/sec/Hz Eb/N 0 Bandwidth LimitedEnergy Limited UWB Usual goal Low signal to noise ratio Bandwidth inefficient
  9. 9. 4G POTENTIAL FOR UWB 3G and beyond
  10. 10. UWB Properties • Extremely difficult to detect by unintended users – Highly Secured • Non-interfering to other communication systems – It appears like noise for other systems • Both Line of Sight and non-Line of Sight operation – Can pass through walls and doors • High multipath immunity • Common architecture for communications, radar & positioning (software re-definable) • Low cost, low power, nearly all-digital and single chip architecture
  11. 11. UWB Emission Limits for GPRs, Wall Imaging, & Medical Imaging Systems Operation is limited to law enforcement, fire and rescue organizations, scientific research institutions, commercial mining companies, and construction companies. 0.96 1.61 1.99 3.1 10.6 GPS Band Source: www.fcc.gov
  12. 12. UWB Emission Limits for Thru-wall Imaging & Surveillance Systems Operation is limited to law enforcement, fire and rescue organizations. Surveillance systems may also be operated by public utilities and industrial entities. 0.96 1.61 1.99 10.6 GPS Band Source: www.fcc.gov
  13. 13. UWB Emission Limit for Indoor Systems 0.96 1.61 1.99 3.1 10.6 GPS Band Source: www.fcc.gov
  14. 14. 0.96 1.61 1.99 3.1 10.6 GPS Band Source: www.fcc.gov UWB Emission Limit for Outdoor Systems Proposed in preliminary Report and Order, Feb. 14, 2002.
  15. 15. First Report and Order, April 22, 2002. 0.01 0.1 1 10 100 -80 -70 -60 -50 Frequency, GHz -40 EIRP, dBm/MHz UWB Band- width must be contained here Actual UWB Emission Limit for Hand-held Systems
  16. 16. Range Vs Data Rate Thursday, August 21, 2014 Dr. M.MEENAKSHI, DECE, CEG, ANNA UNIVERSITY 16
  17. 17. Wireless Body Area Network
  18. 18. WBAN Scenario
  19. 19. WIRELESS ACCESS POINT (PCF MODE) UWB TRANSCEIVER SERVER WIRELESS ACCESS POINT (PCF MODE) UWB TRANSCEIVER WIRELESS ACCESS POINT (PCF MODE) UWB TRANSCEIVER WIRELESS ACCESS POINT (PCF MODE) UWB TRANSCEIVER WIRELESS ACCESS POINT (PCF MODE) UWB TRANSCEIVER DATA BASE CLOUD ALARM TO APPROPRIATE PERSONNEL UWB TR. PROPOSED NETWORK ARCHITECTURE FOR PUBLIC HOSPITALS
  20. 20. WBAN Challenges
  21. 21. Requirements for WBAN • Non-invasive/ remote operation • Bio-compatibility and biological/environment friendliness • Human safety (Low RF emission power) – Limited Specific Absorption Rate (SAR) • Low power Consumption • Scalability for data rate –10Kbps(low data) ~10Mbps(raw data) • Range (say upto 3 meters) • Satisfying spectrum regulatory issues
  22. 22. Technologies for WBAN Thursday, August 21, 2014 Dr. M.MEENAKSHI, DECE, CEG, ANNA UNIVERSITY 22
  23. 23. Comparison with other technologies for WSN
  24. 24. Why UWB for WBAN ? • Bluetooth (802.15.1)  cable replacement technology, no support for multi- hop communication, complex protocol stack, high energy consumption • ZigBee (802.15.4)  energy consumption is higher, interference mitigation is difficult, poor multipath performance, however less complex and cost effective
  25. 25. UWB Characteristics suited to WBAN • Penetration through obstacles • High precision ranging at the cm level • Low electromagnetic radiation • Low processing energy consumption • Low Interference • Security requirements – data confidentiality, authenticity, integrity, freshness
  26. 26. WBAN Channels Thursday, August 21, 2014 Dr. M.MEENAKSHI, DECE, CEG, ANNA UNIVERSITY 26
  27. 27. In-body WBAN Channel Model • 30-35 dB additional loss over free space loss • Path loss exponent ~ between 3 and 4 (depending on the body part considered) • Antenna height / distance also impacts loss • Loss 20 dB more at 5mm compared to at 5 cm
  28. 28. Extra-body WBAN Channel Model • LoS / NLoS • Path loss exponent ~ between 5 and 6 (depending on the body part considered) • NLoS loss more than LoS loss – Diffraction around the human body – Absorption of large amount of radiation by the body • Movement of limbs could cause loss > 30 dB
  29. 29. UWB Transmitter Pulse Generation Modulate Data in Pulse Generator LNA Detector Data out Simplified System; looking at pulse only MF )(tu( )ts Pulse shaping filter Matched Filter •A UWB system uses a long sequence of pulses for communication. •A regular pulse train produces energy spikes (comb-lines) at regular intervals. •Pulse train carries no information and “comb-lines” interfere with conventional radios. Frequency (GHz) -50 -40 -30 -20 -10 0 0 1 2 3 4 5 Time Pulse train
  30. 30. Data Modulation  Pulse Position Modulation (PPM)  Pulse Amplitude Modulation (PAM)  On-Off Keying (OOK)  Bi-Phase Modulation (BPSK)
  31. 31. UWB Transmitter •UWB Impulse systems use pulse position modulation (PPM) •The PPM modulates the position of a pulse about a nominal position. A “1” and a “0” is determined by a pico-second delay T1 or T2 of a mono-pulse. •PPM “smooths-out” the spectrum making the transmitted look almost like noise. •The Pseudo-Random noise coding makes the spectrum appear very-much like noise. •Only a receiver with the same PN-code template can decode the pulse transmission.
  32. 32. 32 Frequency (GHz) -50 -40 -30 -20 -10 0 0 1 2 3 4 5 Time Pulse train Frequency (GHz) -50 -40 -30 -20 -10 0 0 1 2 3 4 5 T1 T2 Time Frequency (GHz) -50 -40 -30 -20 -10 0 0 1 2 3 4 5 Time hopping Nominal pulse train New position after hopping
  33. 33. TH-PPM UWB Tf Ts : data symbol time Tc t pulse wtr(t) Str(t) cfchf s fsfss ph TTeiTNT N TTeiTNT NNC ⋅=⋅≥ ⋅=⋅= === 3.. symboldataperpulsesofnumber: 4.. 4periodcode,2,]2001[codeword =0id Tf Ts Tc t δδδδ Str(t) =1id
  34. 34. Monocycle Shapes for UWB • Monocycle shapes will affect the performance – Gaussian pulse – Gaussian Monocycle – Scholtz’s Monocycle – Manchester Monocycle – RZ- Manchester Monocycle – Sine Monocycle – Rectangle Monocycle
  35. 35. Monocycle Shapes for UWB (cont.) • Gaussian Pulse • Gaussian monocycle – first derivative of Gaussian pulse
  36. 36. Monocycle Shapes for UWB (cont.) • Scholtz’s monocycle - second derivative of Gaussian pulse • Manchester Monocycle
  37. 37. Monocycle Shapes for UWB (cont.) • RZ- Manchester Monocycle • Sine Monocycle
  38. 38. Monocycle Shapes for UWB (cont.) • Rectangle Monocycle
  39. 39. UWB Receiver Pulse Generation Modulate Data in Pulse Generator LNA Detector Data out Simplified System; looking at pulse only MF )(tu( )ts Pulse shaping filter Matched Filter Autocorrelation of binary transmission
  40. 40. 40 UWB versus Traditional Narrow Band Transceiver
  41. 41. All Digital UWB Radio Conventional Integrated Narrowband Transceiver: UWB “Mostly Digital” Radio: D/A I QMIXERLNA PA A/D A/D DIGITAL: F SYNTH ANALOG: MIXER D/A D/A I LNA PA A/D DIGITAL: ANALOG: • Simplicity • Low Cost • Integration • Low Power • Large BW • Ranging • Unlicensed Operation • Coexistence UWB Promises:
  42. 42. Pulse Reception Thursday, August 21, 2014 Dr. M.MEENAKSHI, DECE, CEG, ANNA UNIVERSITY 42 time time Sample Time Pulse Reception Window Pulse Transmission Rate Voltage Receiver Operation Analog On Sampling On Digital Off Analog Off Sampling Off Digital On Analog Off Sampling Off Digital Off Analog On Sampling On Digital Off Only process data from a window of time:
  43. 43. Power Conservation Thursday, August 21, 2014 Dr. M.MEENAKSHI, DECE, CEG, ANNA UNIVERSITY 43 Duty-Cycled To ~1mW (1 Mpulse/s) Always On ~8 mW (32 Mpulse/s) TX DLL CONTROL GAIN A/D DIGITAL OSC BIAS Duty-Cycling Starts
  44. 44. 44 UWB Advantages - Limitations • UWB radio systems have large bandwidth (> 1 GHz). • UWB has potential to address today’s “spectrum drought”. • Emissions below conventional level. • Single technology with 3 distinct capabilities. • Secure transmission, low probability of interception or detection and anti-jam immunity. • Not appropriate for a WAN (Wide Area Network) deployment such as wireless broadband access. • UWB devices are power limited.

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