Development and Performance Assessment of a Real Time High-Resolution RF Channel Sounder
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© 2005, it - instituto de telecomunicações. Todos os direitos reservados. David Ferreira, DL-IT Rafael Caldeirinha, DL-IT | IPL Development and Performance Assessment of a Real Time High- Resolution RF Channel Sounder IGARSS 2011 Vancouver – 29 th July 2011
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IGARSS 2011 Vancouver – 29 th July 2011. Development and Performance Assessment of a Real Time High-Resolution RF Channel Sounder. David Ferreira, DL-IT Rafael Caldeirinha, DL-IT | IPL. Outline. Motivation and objectives Sliding correlation principle Implemented sounder topology - PowerPoint PPT Presentation
Transcript of Development and Performance Assessment of a Real Time High-Resolution RF Channel Sounder
© 2005, it - instituto de telecomunicações. Todos os direitos reservados.
David Ferreira, DL-ITRafael Caldeirinha, DL-IT | IPL
Development and Performance Assessment of a Real Time High-Resolution RF Channel Sounder
IGARSS 2011Vancouver – 29th July 2011
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OUTLINE
Motivation and objectives
Sliding correlation principle
Implemented sounder topology
Performance assessment
System photos
Conclusions and further work
IGARSS 2011
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MOTIVATION
Characterisation and modelling of radiowave propagation in doubly selective channels.
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OBJECTIVES
Design, implementation and test of a Swept Time-Delayed Cross-Correlation (STDCC) RF channel sounder.
Ease in adjusting key sounder parameters allowing to maximise its performance depending on the measurement scenario;
High time resolution of the channel impulse responses (2ns);
Ensure a good overall dynamic range;
Capability to measure multipath components in both amplitude and phase, allowing for Doppler spectrum analysis with post-processing.
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SLIDING CORRELATION PRINCIPLE (1/4)
Typical transmitter section
Typical receiver sectionIGARSS 2011
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SLIDING CORRELATION PRINCIPLE (2/4)
PN sequence generator
Auto-correlation of a PN sequence
Real spectrum of a PN sequence
at 500MHz
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SLIDING CORRELATION PRINCIPLE (3/4)
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SLIDING CORRELATION PRINCIPLE (4/4)
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IMPLEMENTED SOUNDER TOPOLOGYTRANSMITTER BLOCK
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IMPLEMENTED SOUNDER TOPOLOGYTRANSMITTER BLOCK
RF2052 development board
Frequency range: 300MHz to 2.4GHz
Resolution: 0.596Hz
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IMPLEMENTED SOUNDER TOPOLOGYTRANSMITTER BLOCK
DPG2 and AD9739EBZ boards
Sampling frequency: 2500MSPS
14 bits resolution
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IMPLEMENTED SOUNDER TOPOLOGYRECEIVER BLOCK
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IMPLEMENTED SOUNDER TOPOLOGYRECEIVER BLOCK
6GHz Mixer – DM0408LW2
RF/LO Bands: 4 to 8 GHz; IF Band: DC to 2GHz; Losses: 5dB
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IMPLEMENTED SOUNDER TOPOLOGYRECEIVER BLOCK
I/Q Downconverter – HMC-C009
RF/LO Bands: 4 to 8.5 GHz; IF Band: DC to 3.5GHz; Losses: 9dB
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IMPLEMENTED SOUNDER TOPOLOGYRECEIVER BLOCK
Correlation Mixer – ZFM-2-S+
RF/LO Bands: 1 to 1000 MHz; IF Bands: DC to 1GHz; Losses: 6dB
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IF PERFORMANCE ASSESSMENTTEST CONFIGURATION
Possibility to change the cable lengths, therefore the time delay associated to each multipath component;
Possibility to adjust the losses associated to each path.
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IF PERFORMANCE ASSESSMENTSOUNDER PARAMETERS
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IF PERFORMANCE ASSESSMENT
The system is able to distinguish multipath components separated by approximately 2ns.
0 20 40 60 80-65
-60
-55
-50
-45
-40
-35
-30
X: 0Y: -39.63
PDP
Time referenced to the 1st correlation peak (ns)
Pow
er
(dB
m)
X: 1.92Y: -48.68
X: 69.72Y: -36.45
-2 0 2 4 6 8 10-65
-60
-55
-50
-45
-40
-35
-30PDP
Time referenced to the 1st correlation peak (ns)
Pow
er
(dB
m)
RESULTS (1/2)
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Assessment of the dynamic range.
0 10 20 30 40 50 60 70 80 90-65
-60
-55
-50
-45
-40
-35
-30
-25
-20
X: 69.84Y: -62.91
PDP
Time referenced to the 1st correlation peak (ns)
Pow
er
(dB
m)
X: 2.88Y: -37.74
X: 0Y: -23.69
RESULTS (2/2)
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IF PERFORMANCE ASSESSMENT
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RF PERFORMANCE ASSESSMENTTEST CONFIGURATION
Using the same sounder parameters as in the IF bench test.
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RF PERFORMANCE ASSESSMENT
The figure shows two components which correspond to the periodic repetition of the sequence.
RESULTS (1/2)
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0 500 1000 1500 2000-60
-55
-50
-45
-40
-35
-30
-25
-20
X: 2047Y: -29.43
Time (ns)
Rec
eiv
ed
Po
wer
(dB
m)
PDP
X: 0Y: -29.45
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RF PERFORMANCE ASSESSMENT
The figures show preliminary results of Doppler measurements at
18.7GHz.
RESULTS (2/2)
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-100 -50 0 50 1000
0.2
0.4
0.6
0.8
1X: -31.4Y: 1
Doppler spectra
Doppler shift (Hz)
Nor
mal
ise
d lin
ea
r fr
eq
uen
cy r
esp
ons
e
-100 -50 0 50 1000
0.2
0.4
0.6
0.8
1X: 31.21Y: 1
Doppler spectra
Doppler shift (Hz)
Nor
mal
ise
d lin
ea
r fr
eq
uen
cy r
esp
ons
e
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SYSTEM PHOTOSIF-STAGE (1/2)
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IF-STAGE (2/2) SYSTEM PHOTOS
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SYSTEM PHOTOSRF-STAGE (1/2)
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SYSTEM PHOTOSRF-STAGE (2/2)
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SYSTEM PHOTOSDOPPLER MEASUREMENT
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CONCLUSIONS
The developed IF system can successfully distinguish multipath components separated by only 2ns and has a dynamic range around 50dB.
Despite the limitations caused by an RF faulty component, preliminary tests, both in bench as well in an anechoic chamber, show an overall dynamic range for the complete system (IF+RF) of close to 40dB.
By allowing an easy adjustment of the PN sequence properties, either in its length or chip rate, one can adjust the sounder specifications (e.g. dynamic range, time and Doppler resolutions, etc.) to the measurement scenario/geometry.
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FURTHER WORK
Integration of the developed IF stage on other RF front-ends, namely (37, 60 and 300 GHz), allowing for high scalability.
Acquisition of a better data acquisition card, in order to improve the maximum detectable object speed through Doppler analysis of the measured PDP (currently limited to a maximum of 120Hz for a maximum discernible delay of 255ns).
Housing of the developed IF stage allowing for an easy relocation of the equipment over different measurement locations.
IGARSS 2011
| Vancouver – 29th July 2011
© 2005, it - instituto de telecomunicações. Todos os direitos reservados.
Thank you.
IGARSS 2011Vancouver – 29th July 2011
Development and Performance Assessment of a Real Time High-Resolution RF Channel Sounder
E-mails: [email protected] [email protected]
