Cognitive radio system testbed demonstration
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Cognitive Radio System Testbed Demonstration. Dr. Kyutae Lim ([email protected]) Associate Director of Technology Georgia Electronic Design Center, www.gedcenter.org Georgia Institute of Technology. Cognitive Radio Testbed Overview. Cognitive Radio Testbed.

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Cognitive Radio System Testbed Demonstration

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Cognitive radio system testbed demonstration

Cognitive Radio System Testbed Demonstration

Dr. Kyutae Lim ([email protected])

Associate Director of Technology

Georgia Electronic Design Center, www.gedcenter.org

Georgia Institute of Technology


Cognitive radio testbed overview

Cognitive Radio Testbed Overview


Cognitive radio testbed

Cognitive Radio Testbed

  • Cognitive Radio Testbed was built in Georgia Electronic Design Center, Georgia Tech, Atlanta, GA.

  • Perform the real time demonstration of various operations in CR system.

  • Perform the industrial level of evaluation for PHY/MAG and Sensing Technologies.

  • CR Testbed has flexibility in H/W and S/W.

  • Testbed configuration and test procedure can be set by WG and Tiger team.

  • We hope CR testbed to contribute for forging IEEE 802.22 Standard.


Cr testbed system configuration

Equipment

Control

Component

Control

Display

Control

Signal

Generation

Spectrum

Sensing

Received sig.

Analysis

Testbed Control : MATLAB

CR Testbed System Configuration

Signal Generation

Signal Reception

TV

Antenna

DTV Test Receiver

AMP

Vector Signal Analyzer

DTV

Sig Gen

Spectrum Analyzer

Vector

Sig Gen

Receiver

Module

ADC : Data

Acquisition

4 CH DAC


Photo of cognitive radio testbed

Broadcast sig.

generator

Rec. signal

spectrum

Constellation

(OFDMA)

Main

Control

DTV

monitor

RF receiver

module

Vector signal

analyzer

Spectrum

Analyzer

Vector signal

generator

DAC/ADC/

Computer

Photo of Cognitive Radio Testbed


System specification

System Specification


Demo 1 cognitive radio system concept

Demo.1 : Cognitive Radio System Concept

Purpose : Basic CR operation principle

Spectrum Sensing

Co-existance of Incumbent and WRAN

Interference mitigation

Frequency agile operation


Cognitive radio system testbed demonstration

Equipment

Control

Component

Control

Display

Control

Signal

Generation

Spectrum

Sensing

Received sig.

Analysis

Testbed Control : MATLAB

Testbed Configuration: Demo.1

Signal Generation

Signal Reception

TV

Antenna

DTV Test Receiver

AMP

Vector Signal Analyzer

DTV

Sig Gen

Spectrum Analyzer

Vector

Sig Gen

Receiver

Module

ADC : Data

Acquisition

4 CH DAC


Spectrum sensing tv signals only

Spectrum Sensing (TV signals only)


Cognitive radio system testbed demonstration

WRAN Interferer (overlapped)

WiMax signal used as WRAN


Ofdma constellation evm

OFDMA Constellation / EVM

OFDMA communication failed.

No constellation.

EVM does not meet the criteria


Cognitive radio system testbed demonstration

TVs-WRAN Co-Existence (WRAN in vacant channel)


Ofdma constellation evm1

OFDMA Constellation / EVM

OFDMA communication working well.

Good constellation.

EVM meet the criteria


Dynamic frequency switching i new primary user signal into the wran channel

Dynamic Frequency Switching - I- New primary user signal into the WRAN channel -


Ofdma constellation evm2

OFDMA Constellation / EVM

Communication failed.


Dynamic frequency switching ii wran signal move to another vacant channel

Dynamic Frequency Switching - II- WRAN signal move to another vacant channel -


Ofdma constellation evm3

OFDMA Constellation / EVM

Communication in work.


Demo 2 evaluation of spectrum sensing technology

Demo.2 : Evaluation of Spectrum Sensing Technology

Purpose : Verifying Various Spectrum Sensing Technologies

Generating Spectrum Environment

Energy Detection: MRSS

Feature Detection: AAC


Cognitive radio system testbed demonstration

Equipment

Control

Component

Control

Display

Control

Signal

Generation

Spectrum

Sensing

Received sig.

Analysis

Testbed Control : MATLAB

Testbed Configuration: Demo.2

Signal Generation

Signal Reception

TV

Antenna

DTV Test Receiver

AMP

Vector Signal Analyzer

DTV

Sig Gen

Spectrum Analyzer

Vector

Sig Gen

Receiver

Module

ADC : Data

Acquisition

4 CH DAC


Dual sensing strategy presented mar 06

Dual Sensing Strategy (presented Mar 06)

Begin Sensing

Energy Detection

for wide band

(Analog, RSSI, MRSS, FFT…)

Fine/Feature Detection

for single channel

MAC

(Select

single channel)

Spectrum

Usage

Database

(BS)

FFT

CSFD

Field

Sync

Optimum

Radiometer

Spectral

Correlation

AAC

Multi-cycle

Detector

ATSC

Segment

Sync

occupied?

Y

End Sensing

N


Input signal spectrum time domain waveform

Input Signal Spectrum / Time-domain Waveform


Coarse mrss

Coarse MRSS


Fine mrss with threshold detection

Fine MRSS with Threshold Detection


Aac for ofdm wlan 802 11a

AAC for OFDM (WLAN 802.11a)

Get two clues (due to short and long preamble) !!


An example of scheduling algorithm for dfh

An Example of Scheduling Algorithm for DFH

WRAN A

Channel 1

  • A WRAN system maintains two channels (operating channel and candidate channel)

  • If WRAN BSes can communicate each other to schedule the time switching to the candidate channel, collision can be completely avoided.

    • Even if collision occurs on the candidate channel, it is only in very short time (about quite time).

WRAN B

Channel 2

Channel 3


Demo 3 evaluation of protecting incumbent user from wran signal

Demo.3 : Evaluation of protecting Incumbent user from WRAN signal

Generation of various fading environment

DTV Signal quality measurement in Fading

Coexistence of DTV and WRAN

Signal quality measure for DTV and WRAN


Cognitive radio system testbed demonstration

Equipment

Control

Component

Control

Display

Control

Signal

Generation

Spectrum

Sensing

Received sig.

Analysis

Testbed Control : MATLAB

Testbed Configuration: Demo.3

Signal Generation

Signal Reception

TV

Antenna

DTV Test Receiver

AMP

Vector Signal Analyzer

DTV

Sig Gen

Spectrum Analyzer

Vector

Sig Gen

Receiver

Module

ADC : Data

Acquisition

4 CH DAC


Atsc test 1 fading 1

ATSC Test 1 – Fading (1)

  • ATSC with Fading channel environment

  • ATSC

    • Ch. 39 (center freq: 623 MHz)

    • Level: -10 dBm

    • Fading

      • Rayleigh (Pass loss: 3 dB, freq ratio = 1.00)

      • EASY3 for DTV test

  • Number of DTV signals and Fading parameters can be easily adjusted


Atsc test 1 fading 2

ATSC Test 1 – Fading (2)


Atsc test 1 fading 3

ATSC Test 1 – Fading (3)

Signal quality can be measured


Atsc test 1 fading 4

ATSC Test 1 – Fading (4)`````````````````````````````````````````````````````````````````````````````````````````````````````````````````

Various graphs enables signal quality analysis for DTV signal


Atsc test 2 w wimax 1

ATSC Test 2 – w/ WiMax (1)

  • ATSC with Fading plus OFDMA signal to the adjacent channel

  • ATSC

    • Ch. 39 (center freq: 623 MHz)

    • Level: -10 dBm

    • No fading

  • WRAN (WiMax signal is used)

    • Freq: 616.5 MHz, BW: 7 MHz

    • Level: 0 dBm


Atsc test 2 w wran 2

ATSC Test 2 – w/ WRAN (2)

ATSC

  • Spectrum

WiMax Mask

WiMax


Atsc test 2 w wran 3

ATSC Test 2 – w/ WRAN (3)


Atsc test 2 w wran 4

ATSC Test 2 – w/ WRAN (4)

Signal quality is little bit degraded

due to OFDM signal at adjacent channel


Atsc test 2 w wran 5

ATSC Test 2 – w/ WRAN (5)

OFDM signal


Atsc test 2 w wran 6

ATSC Test 2 – w/ WRAN (6)

Still OK!

  • OFDM (WiMax) performance


Summary

Summary

  • CR Testbed has built in GEDC, Georgia Tech

    • Maximum H/W flexibility

    • Full S/W control: MATLAB

    • Easy to expand for evaluating Sensing, Interference, MAC, PHY …

  • CR Testbed has been demonstrated

    • CR Concept and frequency agile operation

    • Spectrum sensing technology evaluation

    • Emulation of various fading channel environment

    • Evaluation of WRAN signal to interfere DTV reception


Suggestion

Suggestion

  • Realistic spectrum environment can generated repeatedly.

  • The testbed can be customized to perform various test/evaluation.

  • The parameters and figure-of-merit can be defined by WG.

  • Standard procedure for evaluation can be defined by WG.

  • Let’s use this testbed for standard evaluation platform for PHY and Sensing technology !!!


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