thesis a. rinaldi - eng

7/27/2019 Thesis A. Rinaldi - ENG

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Universita di Messina - Facolta di Ingegneria

Emulation of a Radio Link by means of Software Radio

Supervisors

Prof. Salvatore Serrano

Prof. Giuseppe Campobello

Candidate

Arturo Rinaldi

Masters Degree in Electronics Engineering - Academic Year 2010/11Messina, November 10th 2011
mailto:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]


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Goal of the thesis work

The making of a learning tool for the analisys of the digital modulationsin different communication channels

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Arturo Rinaldi - Emulation of a Radio Link by means of Software Radio
mailto:[email protected]:[email protected]


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The simulated channels were :

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The simulated channels were : Wired : AWGN

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Wireless : Rayleigh and Rician

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Wireless : Rayleigh and Rician Verify the correspondence between the theoretical and experimental

results of the BER (Bit Error Rate)

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Provide complementary tools to show how audio and video files aremodified under the effect of the transmission channels

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Provide complementary tools to show how audio and video files aremodified under the effect of the transmission channels

The gr-bertool was built by using the open-source DSP platform GNURadio

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GNU Radio

GNU Radio is an open-source softwaretoolkit providing a huge library ofblocks for Digital Signal Processing

(DSP) written in C++ which can becombined together in order to build anddevelop radio applications

Python Flow Graph

(Created using the processing blocks)

USB Interface / Gigabit Ethernet

Generic RF Front End

SWIG (Port C++ blocks to Python)

GNU Radio Signal Processing Blocks

( USRP / USRP 2 )

Gnu Radio Companion (GRC), XML

(C++)

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GNU Radio

GNU Radio is an open-source softwaretoolkit providing a huge library ofblocks for Digital Signal Processing

(DSP) written in C++ which can becombined together in order to build anddevelop radio applications

It is provided with a graphical interfaceto ease its learning curve (GRC : GNU

Radio Companion)

Python Flow Graph

(Created using the processing blocks)

USB Interface / Gigabit Ethernet

Generic RF Front End

SWIG (Port C++ blocks to Python)

GNU Radio Signal Processing Blocks

( USRP / USRP 2 )

Gnu Radio Companion (GRC), XML

(C++)

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Software-Defined Radio : an introduction

GNU Radio was developed to be in use of Software-Defined Radio(SDR), a new paradigm of communication systems

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A receiver is an SDR device if its communication functions are made asreconfigurable software working on ad hoc hardware

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So its possible to implement different software transmission standardsby using only one device

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So its possible to implement different software transmission standardsby using only one device

An SDR sytem is also able to recognize and avoid possible interferenceswith other transmission channels

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The developed tool : gr-bertool

The tool main GUI

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BER experimental verification

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Real-Time BER experimental verification

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Complementary tools

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The Bit Error Rate (BER) of a digital modulation, is the number of biterrors divided by the total number of transferred bits during a studiedtime interval

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Lets verify the BER theoretical values with the experimental ones byvarying the signal-to-noise ratio Eb/N

0

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Lets verify the BER theoretical values with the experimental ones byvarying the signal-to-noise ratio Eb/N0

From digital communications theory is well known that for a Q-PSKmodulation the Bit Error Rate is given by :

Pb = Q2EbN

0

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This set of tools calculates the BER ina range ofEb/N0 values given by minand max with the opportunity tochoose the increase step size

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We can enable or disable the GrayCoding

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We can enable or disable the GrayCoding

By clicking on the Plot button the BERcurves are showed in a simple BER vsEb/N0 diagram

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We can see a perfect agreement between the theoretical results and theexperimental ones :

(a) BER AWGN BPSK (b) BER AWGN Q-PSK (c) BER AWGN 8-PSK

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Real-Time BER and signal constellation evolution

This tool allow us to show the real-timeBER and signal constellation evolutionin the three different types ofexaminated transmission channels

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In the following example well show the

BER evolution in the Rician Channel inthe range ofEb/N0 values going from15 dB to 0 dB

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Once started the BER value settles tothe BER value corresponding to

Eb/N0 = 0 dB about equal to 0.11

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Eb/N0 = 0 dB about equal to 0.11 Ch1 Experimental Value ; Ch2

Theoretical Value

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Eb/N0 = 0 dB about equal to 0.11 Ch1 Experimental Value ; Ch2

Theoretical Value

Lets see the evolution.... 12 of 36



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Real-Time BER evolution

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The signal constellation

Lets consider a generic transmission scheme for a TLC system.

Tx RxTx Channel

m(t) s(t) r(t) d(t)

S D

Figure : Generic block diagram for a TLC system

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Lets consider a generic transmission scheme for a TLC system.

Tx RxTx Channel

m(t) s(t) r(t) d(t)

S D

Figure : Generic block diagram for a TLC system

In the absence fo any noise in the channel the generci transmittedsymbol si will be correctly received. The plot of the received symbols isknows as Constellation of the digital modulation.

s0 (11)

s3 (01)

s2 (00)

s1 (10)

Figure : Constellation of a QPSK modulation19 of 36



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The presence of noise in the channel modifies phase and amplitude ofthe transmitted symbols and so the received symbol ri is not onebelonging to the constellation showed before

s0 (11)

s3 (01)

s2 (00)

s1 (10)

ri

The transmitted si symbol is not

correctly received

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Evolution of the Signal Constellation

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Image Transmission

This tool allow us to observe how themost common image formats areaffected by digital modulations

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Image Transmission


We studied the effects over the

simulated channels (AWGN, Rayleigh eRician) for a fixed value ofEb/N0 = 0 dB and Q-PSK digitalmodulation for a Jpeg image

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Image Transmission


We studied the effects over the

simulated channels (AWGN, Rayleigh eRician) for a fixed value ofEb/N0 = 0 dB and Q-PSK digitalmodulation for a Jpeg image

Lets see the results......

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Image Transmission : AWGN Channel

(a) Original (b) AWGN

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Image Transmission : Rician Channel

(c) Original (d) Rician

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Image Transmission : Rayleigh Channel

(e) Original (f) Rayleigh

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Audio Transmission

This tool allow us to observe how themost common audio formats areaffected by digital modulations

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Audio Transmission


We studied the effects over thesimulated channels (AWGN, Rayleigh e

Rician) for a fixed value ofEb/N0 = 10 dB and Q-PSK digitalmodulation

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Audio Transmission


We studied the effects over thesimulated channels (AWGN, Rayleigh e

Rician) for a fixed value ofEb/N0 = 10 dB and Q-PSK digitalmodulation

We took as sample the wav fileplay it sam.wav with the following

specifications :

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Audio Transmission

Specifications of the sample file

play_it_sam.wav :

File Size: 1.76MBit Rate: 1.41M

Encoding: Signed PCM

Channels: 2 @ 16-bit

Samplerate: 44100Hz

Replaygain: off

Duration: 00:00:10.00

Lets see the results....

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Audio Transmission

(g) Originale (h) Canale AWGN

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Audio Transmission

(i) Rician (j) Rayleigh

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Conclusions

Why using gr-bertool ? Advantages

Its an helpful tool for the teacher to use in TLC courses

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Conclusions



The student can find a quick verification with the learnt notions duringclasses

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Conclusions




It has an user-friendly GUI

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Conclusions




It has an user-friendly GUI Its open-source !

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Conclusions

Future Developments

Addition of other components for transmission by using the USRP(through USB) and USRP2 (through Gigabit Ethernet) boards to studythe real-time signals evolution

(k) USRP1 (l) USRP2

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Conclusions

Future Developments

Addition of other components for transmission by using the USRP(through USB) and USRP2 (through Gigabit Ethernet) boards to studythe real-time signals evolution

(m) USRP1 (n) USRP2

Implementation of other modules for the network protocols (i.e.802.11n, Bluetooth) always for learning goal

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Contact Information

Arturo RinaldiFreelance Collaborator @ DIECIIAddress : Dep. of Electronics Engineering (DIECII) - C.da di Dio, 98166 Messina (Italy)E-mail : [email protected] : +39-090-3977376 ; Mobile : +39-340-5795584 (Whatsapp)Skype : arty.net ; Facebook : arty.netTwitter : artynet2 ; LinkedIn : Arturo Rinaldi

Prof. Giuseppe Campobello, Ph.D.Researcher in TelecommunicationsAddress : Dep. of Electronics Engineering (DIECII) - C.da di Dio, 98166 Messina (Italy)E-mail : [email protected] : +39-090-3977378

Prof. Salvatore Serrano, Ph.D.Researcher in Telecommunications

Address : Dep. of Electronics Engineering (DIECII) - C.da di Dio, 98166 Messina (Italy)E-mail : [email protected] : +39-090-3977522

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thesis a. rinaldi - eng

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