Ultra-Wideband Research and Implementation

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Ultra-Wideband Research and Implementation

• By Jarrod Cook and Nathan Gove
• Advisors
• Dr. Brian Huggins
• Dr. In Soo Ahn
• Dr. Prasad Shastry

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Presentation Outline

• Introduction
• Overview
• Project Summary
• Spectrum Overview
• Modulation
• Project Issues
• Time Constraints
• Sampling Rates
• ADC / DAC issue
• Project Schedule
• Website Updates
• Project Milestones
• Model
• Block Diagram
• Frame Synchronization
• Integration with CCS and DSPs
• Hardware
• 2/3 of Hardware Received
• LO Tested

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Introduction to UWB

• Ultra-wideband technology is a wireless
  transmission technique approved for unlicensed
  use in 2002 under the FCC Part 15
• Ideal for portable multimedia devices because of
  its inherent low power consumption and high bit
  rates

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Why Research UWB?

• UWB is likely to revolutionize the consumer
  electronic market in the near future.
• Wireless USB devices
• Wireless communication for High-Definition
  devices
• UWB has the power to eliminate the majority of
  wires to and from multimedia devices

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Overview

• Brief History
• IEEE 802.15.3a
• ECMA 368 and 369
• Consumer Electronics Demand
• High data-rate wireless transmissions
• Low power consumption for portable devices
• UWB allows data rates equivalent to
• USB 2.0 (480 Mb/s)

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Project Summary

• The goal of this project is to complete a
  scaled-down version of a UWB transceiver pair.
• Specifically, we are focusing on the following
• Understanding the theory
• Simulink modeling
• DSP implementation
• RF transceiver hardware
• Testing

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UWB Spectrum Overview

• Power spectral density
• -41.3 dBm/MHz
• FCC part 15 limit
• Frequency Range
• 3.1 to 10.6 GHz
• Sub-bands

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Modulation

• QPSK or 4-QAM
• Gray Coded Mapping
• Symbols
• Used for data rates from80 to 200 Mb/s
• I Q
• 16-QAM or DCM
• Used for data rates from320 Mb/s to 480 Mb/s

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OFDM
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OFDM

• Benefits
• Resistance to multi-path fading
• Spectrum
• Full ECMA standardized UWB spectrum
• Scaled-down project spectrum

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Project Issues

• Due to Time Constraints
• Power Limitation
• Must be overlooked for this initial project
• Output of quadrature modulators exceed
  limitations
• Transmission Bandwidth / Data Rate
• ACD and DAC are not sufficient
• Audio Development Kit
• UWB Coding Specifications 20 Met
• Pseudo-random code / spreading / time
  interleaving
• Forward Error Correcting
• Data frame will not include full preambles /
  headers

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Project Issues

• Sampling Times
• Simulink requires information at equal times
• Must be very careful when changing sampling rates
• ADC / DAC Issues
• DAC
• Need to Transmit In Phase and Quadrature Phase
  Components
• DACs can only output real numbers
• Two DACs are required
• Board only has one DAC
• Daughter Boards Required
• Both
• With faster converters, wider bandwidths possible

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Overall Tx / Rx Block Diagram
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Simulink Model

• Model
• Frame Synchronization
• Preamble Complete

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Updated Project Schedule
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Updates on Project Website

• UWB Website Updates

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Progress

• DSP Platforms received
• C6416 DSK

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Integration of Simulink with CCS

• To use the DSP boards, all that has to be added
  to the model is the C6416DSK block.
• Simulink has a blockset for this model
• Allows use of ADC and DAC
• LEDs
• DIP Switches
• Software Reset
• Running the model automatically launches CCS
  which converts the model to C-code and uploads it.

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Simple DSP Test with CCS

• DSP Platform Hardware
• Tested with Simulink and Code Composer Studio
  (CCS)
• Used a FIR Filter for a quick test

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Simple Test Cont.

• Once we figured out how to successfully upload
  models, we did a quick FIR filter model to test
  the model.
• Sampling rate 32 kHz
• Passband 0 to 5 kHz
• Stopband 6 kHz
• Results
• Did a quick frequency sweep of the filter through
  the DSP to visually confirm the DSP was working

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RF Hardware

• The RF local oscillator and direct quadrature
  modulator have arrived.

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Local Oscillator Test

• The oscillator was tested on the spectrum
  analyzer to verify that it met the specifications
  stated in the data sheet.
• Data sheet specs
• Tunable from 3.35 to 3.55 GHz
• Typical power output 4.7 dBm (1.5 minimum)
• Current draw 41 mA
• Harmonic levels -7 and -16 dBc

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Local Oscillator

• Tests performed
• Output frequency vs. tuning voltage
• Output power vs. tuning voltage
• Harmonic power levels
• The frequency vs. tuning voltage matched up with
  the data sheet nicely
• The output power was much lower than the specs
  (on the order of 0.5 to 1.2 dBm)
• Determined the loss of the coax, DC block, and
  connectors to be around 1 dB. Therefore, results
  are more normal
• Harmonic Power levels matched data sheet specs

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Local Oscillator
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Local Oscillator
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Local Oscillator
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Local Oscillator
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Local Oscillator
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Local Oscillator
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Future hardware testing

• Quadrature Modulator
• Quadrature De-Modulator
• Interconnecting all the hardware for testing
• Transmission lines as channel before wireless
• Signal leaves DSP on a 3.5mm audio jack, and must
  be received by the modulator with an SMA
  connector.
• Impedance mismatches?

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Hardware Connections
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Future Work

• Current To Do List

• Previous To Do List

• Baseband processor
• Increase complexity
• Research UWB channels (no longer implementing)
• Determine maximum feasible sampling rate
• Purchase DSP board
• Implement synchronous coherent detection for
  receiver
• RF Transmitter
• Find a suitable quadrature modulator
• Determine and purchase hardware
• Model and Design (no longer implementing)
• Fabricate hardware (no longer implementing)
• Antenna research (no longer implementing)
• RF Receiver
• LNA Design and modeling (N. L. I.)
• Determine and purchase hardware
• Fabricate hardware (N. L. I.)
• Testing

• Transmitter
• Implement Daughterboard DACs and ADCs
• Receiver
• Complete Frame Synchronization
• Pulse on Frame Start
• Frame Alignment
• Implement Carrier Synchronization
• Using the Pilot Signals correct for the phase
  error.
• Testing
• System Integration
• Full system testing
• Bandwidth measurements
• Bit Error Rates
• Other common communication systems measurements.

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Questions
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U W B Standards