Research Institute for Communication, Information and Ergonomics

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Evaluation of Smart Antenna Technologies with a
Broadband Multichannel Reception Testbed

• FGAN-FKIE
• Wolfgang Foerster, Bruno Demissie, Dagobert Baum
• September, 23rd, 2008

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Overview

• Introduction
• Testbed
• Blind signal separation algorithms
• Experimental results
• Summary

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Broadband Multichannel Reception with Smart
Antennas

• Advantage of multichannel reception
• Simultaneous and uninterrupted reception of all
  signals from within a broad frequency band

• Advantage of using smart antennas
• Potential to extract all signals of interest from
  the monitored frequency band and to submit them
  to further narrowband processing
• Potential to take bearings of all signals of
  interest simultaneously

• Limitations of present-day industry solutions
• Normally signals simultaneously overlapping in
  frequency and time cannot be received separately
  nor can bearings be taken of them.

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HF Broadband Multichannel Reception Testbed

• Key features
• Broadband multichannel reception with
  instantaneous bandwidths between 4 MHz and 6.7
  MHz
• Spatio selective reception and direction finding
  through the use of an antenna array and
  algorithms for spatial filtering and
  superresolution direction finding.

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Antenna Array, Geometry for omnidirectional
Reception
Antenna Array
Frequency range 4 MHz 15 MHz Sensors
Active Monopoles Number of sensors 10 Outer
radius 65 m Inner radius 65 m/2.13
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Algorithms for Spatial Filtering

• Conventional Signal Copy (SC)
• Time-Frequency Blind Beamforming (TFBB)
• Deterministic Blind Beamforming (DBB)

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Data Model
Antenna array output signal
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Least Squares Solution
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Conventional Signal Copy
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Time-Frequency Blind Beamforming
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Deterministic Blind Beamforming Algorithm
Key property
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Test Scenario
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TFBB-Filtering, experimental Results I
Extraction of the pulsed narrowband signal via
spatial filtering
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TFBB-Filtering, experimental Results II
Extraction of the fading signal via spatial
filtering
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TFBB-Filtering, experimental Results III
Extraction of the broadband signal via spatial
filtering
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Signal Copy Filtering, experimental Result
Extraction of the broadband signal via spatial
filtering
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Test Scenario, Zoom
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DBB-Filtering, experimental Results I
Extraction of the broadband signal via spatial
filtering
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DBB-Filtering, experimental Results II
Extraction of the pulsed narrowband signal via
spatial filtering
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Pulsed Signal versus Time
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Pulsed Signal versus Time, Zoom
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Summary

• Presentation of a broadband multichannel
  reception Testbed for the evaluation of smart
  antenna technologies.
• Presentation of two new methods for blind signal
  separation.
• Presentation of results concerning the first
  experimental verification of the new methods.

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