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

| Vancouver – 29th July 2011

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MOTIVATION

Characterisation and modelling of radiowave propagation in doubly selective channels.

IGARSS 2011

| Vancouver – 29th July 2011

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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.

IGARSS 2011

| Vancouver – 29th July 2011

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SLIDING CORRELATION PRINCIPLE (1/4)

Typical transmitter section

Typical receiver sectionIGARSS 2011

| Vancouver – 29th July 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

IGARSS 2011

| Vancouver – 29th July 2011

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SLIDING CORRELATION PRINCIPLE (3/4)

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SLIDING CORRELATION PRINCIPLE (4/4)

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| Vancouver – 29th July 2011

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IMPLEMENTED SOUNDER TOPOLOGYTRANSMITTER BLOCK

IGARSS 2011

| Vancouver – 29th July 2011

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IMPLEMENTED SOUNDER TOPOLOGYTRANSMITTER BLOCK

RF2052 development board

Frequency range: 300MHz to 2.4GHz

Resolution: 0.596Hz

IGARSS 2011

| Vancouver – 29th July 2011

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IMPLEMENTED SOUNDER TOPOLOGYTRANSMITTER BLOCK

DPG2 and AD9739EBZ boards

Sampling frequency: 2500MSPS

14 bits resolution

IGARSS 2011

| Vancouver – 29th July 2011

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IMPLEMENTED SOUNDER TOPOLOGYRECEIVER BLOCK

IGARSS 2011

| Vancouver – 29th July 2011

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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

IGARSS 2011

| Vancouver – 29th July 2011

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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

IGARSS 2011

| Vancouver – 29th July 2011

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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

IGARSS 2011

| Vancouver – 29th July 2011

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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.

IGARSS 2011

| Vancouver – 29th July 2011

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IF PERFORMANCE ASSESSMENTSOUNDER PARAMETERS

IGARSS 2011

| Vancouver – 29th July 2011

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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)

IGARSS 2011

| Vancouver – 29th July 2011

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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)

IGARSS 2011

| Vancouver – 29th July 2011

IF PERFORMANCE ASSESSMENT

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RF PERFORMANCE ASSESSMENTTEST CONFIGURATION

Using the same sounder parameters as in the IF bench test.

IGARSS 2011

| Vancouver – 29th July 2011

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RF PERFORMANCE ASSESSMENT

The figure shows two components which correspond to the periodic repetition of the sequence.

RESULTS (1/2)

IGARSS 2011

| Vancouver – 29th July 2011

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)

IGARSS 2011

| Vancouver – 29th July 2011

-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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IGARSS 2011

| Vancouver – 29th July 2011

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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IGARSS 2011

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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.

IGARSS 2011

| Vancouver – 29th July 2011

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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: david.ferreira@co.it.pt rcaldeirinha@estg.ipleiria.pt