Presentation given in a Academic Seminar

1. A Presentation on
SOFTWARE DEFINED RADIO
Presented by
Kumar Vimal
Under guidance of
Preetha M. Kuroop
School Of Engineering
CSE, VII Sem
School Of Engineering

2. CONTENTS
INTRODUCTION
What is SDR
Histrory and Evaluation of SDR
Motivations
METHODS
How SDR works
Architecure of SDR
Software Common Architecure
CORBA
Available Tools: GNU Radio, USRP and Phi
RESULTS
STANDERD AND REGULAROTORY
Application Of SDR
ISDR
DISCUSSION
Benifits
Disadvantages
Challanges in SDR
Conclusion

3. Introduction
Methods
Results
Discussion
What is Software Defined Radio(SDR)?
?
To know SDR let's talk about a radio first!

4. Introduction
Methods
Results
Discussion
BASIC BUILDING BLOCK OF A RADIO
Increase amplitude of signal
multiply by constant
Move signal from RF to
baseband (original signal)
HOW?
Remove frequency components
HOW?
Fourier Series Expansion

5. Introduction
Methods
Results
Discussion
The Theory Behind Radio Technology: Fourier Series
Jean Baptiste Joseph Fourier (1768-1830)
French mathematician and physicist
●
Idea:
“any” periodic function can be decomposed
into an (infinite) sum of sines and cosines“

6. Introduction
Methods
Results
Discussion
The Theory Behind Radio Technology: Fourier Series
Fourier Series
describes the frequency content of periodic signals
Different Time Domain signals have different
harmonics (# and magnitude)

7. Introduction
Methods
Results
Example: Square Pulse, infinite # harmonics!
With 250 harmonics:
Gibbs phenomenon
at discontinuity
Discussion

8. Introduction
Methods
Example: Sawtooth Wave
Results
Discussion

9. Introduction
Methods
Results
Discussion
Example: Triangle Wave
Rect-wave: poor TD quality with 25 harmonics
Sawtooth-wave: poor TD quality with 25 harmonics
Triangle-wave: pretty good TD quality with 10 harmonics
Some TD signals are suited better for
transmission than others (less harmonics)

10. Introduction
Methods
Results
Discussion
What is Modulation
Modulation: multiplication of baseband signal by a carrier wave
Periodic signal can be expanded into series of sine + cosine
 apply the above expression to every single one of those.
Move arbitrary baseband signal into higher bands

11. Introduction
Methods
Results
Fundamental Blocks: Why is Modulation Necessary?
At least 2 reasons:
1. different signals from different systems do not interfere
Example: - broad band cable services
- Public TV and Radio (wireless services)
2. move the payload signal to frequency where it can be
transmitted most easily
Problem: - signal attenuation in wires
- free space signal attenuation
Discussion

12. Introduction
Methods
Results
Discussion
What is Filtering?
Input Signal
Filter Response
Output Signal

13. Introduction
Methods
Results
Discussion
Fourier Series: Continuous and Discrete
Nice, but all of this was for continuous signals,
What about discrete (digital) samples?
Fourier works in digital, too: Discrete Fourier Transform

14. Introduction
A Radio?
Methods
Results
Discussion

15. Introduction
Methods
A Conventional Radio: all in Analog
Results
Discussion

16. Introduction
Methods
Results
Discussion
Issues With Conventional Radios
These Radio systems were designed to communicate using
one or two waveforms.
Two groups of people with different types of traditional radio
were not able to communicate due to were not able to
communicate.
> Can be costlier during war and peace
Diffrent set of h/w for diffrenet type of radio communication.
Example of mobile phone having wifi,bluetooth and GSM
antena.

17. Introduction
Methods
Results
Discussion
What is SDR?
The SDR Forum, working in collaboration with the
IEEE P1900.1 group defines SDR technology as
"Radio in which some or all of the
physical layer functions are software
defined"

18. Introduction
Methods
Results
Discussion
What is SDR?
International Telecommunicaion Union (ITU) defined SDR
in its REPORT ITU-R M.2117 as:
“A radio in which the RF operating
parameters including, but not limited to,
frequency range, modulation type, or
output power can be set or altered by
software, and/or the technique by which
this is achieved“

19. Introduction
Methods
Results
Discussion
SDR in easy words
Refers to a technique in which all the processing is
done in software.
The processing mentioned include mixing, filtering,
demodulation etc
The software can be used to implement different
demodulation scheme and different standards can be
implemented in the same device.
The software can be updated so the device doesn’t
become obsolete with time.

20. Introduction
Methods
Results
SDR EXPLAINED
Discussion

21. Introduction
Methods
Results
Discussion
History and Evaluation of SDR
The term "Software Defined Radio" was coined in 1991 by
Joseph Mitola, who published the first paper on the topic in 1992
Software-defined radios have their origins in the defense sector since
the late 1970s in both the U.S. and Europe (for example, Walter
Tuttlebee described a VLF radio that used an ADC and an 8085
microprocessor)
One of the first public software radio initiatives was a U.S. military
project named SpeakEasy.
The primary goal of the SpeakEasy project was to use programmable
processing to emulate more than 10 existing military radios, operating
in frequency bands between 2 and 2000 MHz.
SpeakEasy design goal was to be able to easily incorporate new
coding and modulation standards in the future, so that military
communications can keep pace with advances in coding and
modulation techniques.

22. Introduction
Methods
Results
Discussion
MOTIVATIONS
Commercial wireless communication industry is currently
facing problems due to constant evolution of link-layer
protocol standards (2.5G, 3G, and 4G)
Existence of incompatible wireless network technologies in
different countries inhibiting deployment of global roaming
facilities
Problems in rolling-out new services/features due to
wide-spread presence of legacy subscriber handsets.

23. Introduction
Methods
Results
How SDR works?
Discussion

24. Introduction
Methods
Results
IDEAL SDR
Antenna
Low
Pass
Filter
Analog to
Digital
Converter
Digital
Signal
Processor
Block Diagram of Ideal SDR Receiver
High Frequency
Requires High Sampling Rate ADC
Costly, Power Hungry
High Speed Processor to Process High Sample Rate
Much Costly, Huge Power Consumption
non feasible solution for commercial applications!
Discussion

25. Introduction
Methods
Results
Discussion
IDEAL SDR
High Frequency
 Requires High Sampling Rate ADC
 Costly, Power Hungry
 High Speed Processor to Process High Sample Rate
 Much Costly, Huge Power Consumption
Thus a non feasible solution for commercial applications!

26. Introduction
Methods
Results
Discussion
PRACTICAL SDR ARCHITECTURE
 Analog RF Front-End still required:
 Digital-analog conversion, DAC/ADC
 RF, IF Filtering
 Mixing IF   RF
 Amplification
 Antennas

27. Introduction
Methods
SDR COCEPT
Results
Discussion

28. Introduction
Methods
Results
Discussion
SDR COCEPT
The base-band devices may include general purpose processors (GPP), digital signal
processors (DSP) and field programmable gate arrays (FPGA) and are supported by the
applications programming interface (API) of the radio software system (Software Common
Architecture).
The SDR may thusinclude traditional sequential “turing machine” software sequences as
well as codedhardware functions that are optimized for the particular desired waveform.
(The “software”of the SDR may thus include both traditional program coding as well as
logic gate coding.)
.
Fig: Basic
Architecture
of a SDR

29. Introduction
Methods
Results
Discussion
SOFTWARE COMMON ARCHITECURE
“Software communications architecture” (SCA) provides a real-time software
operating-system environment to support the dynamic waveform generation and signal
processing aspects of a radio . as well as the administrative aspects for radio installation
and change control.
Such an example of standardized architecture of hardware and software will lead to
generic, flexible radio systems which may be loaded with applications to suit particular
operating scenarios.
SDR may be flexible enough to operate in several modes at the same time and some may
be capable of changing or adding modes while continuing operation in other modes.
Fig: SCA
interfaces used in
the SDR design

30. Introduction
Methods
Results
Discussion
CORBA (Common Object Request Broker Architecture)
CORBA is the Object Management Group’s open architecture that provides the infrastructure
for computer applications to work together over a network.
CORBA has been chosen as the middleware layer of the Software Communications
Architecture, because of the wide commercial availability of CORBA products and its industry
acceptance.
CORBA is used to provide a cross-platform middleware service that simplifies standardized
client/server operations in this distributed environment by hiding the actual communication
mechanisms under an Object Request Broker software bus

31. Introduction
Methods
Results
Discussion
Tools Available
GNU Radio
a FOSS development toolkit that provides
signal processing blocks to implement software
radios.
primarily written using the Python and supplied
performance-critical signal processing path is
implemented in C++
Need hardware antena Interface
e.g. Sound interface ,USRP, Phi,Comedi etc.

32. Introduction
Methods
Results
Discussion
Tools Available
The Universal Software Radio Peripheral (USRP)
(USRP) is a device developed by Ettus Research LLC, which
turns general purpose computers into flexible SDR plat-forms.
Core od USRP is motherboard with four high-speed ADCs and
DACs and an Altera Cyclone EP1C12 FPGA.
Fig: A rev 3 USRP1 platform, serial #140, with an attached TVRX daughterboard

33. Introduction
Methods
Results
Discussion
Indian Software Defined Radio (ISDR)
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BLOCK DIAGRAM OF ISDR
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28.224MHz
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34. Introduction
Methods
Results
Discussion
Indian Software Defined Radio (ISDR)
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BLOCK DIAGRAM OF ISDR
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35. Introduction
Methods
Results
Discussion
Applications Of SDR Technology
SDR use in public safety
SDR use in the military
Commercial use of SDR

36. Introduction
Methods
Results
Discussion
Benifits Of SDR Technology
User benefits
Manufacturer benefits
Wireless access systems (WAS) including radio local
area networks (RLAN)
Public protection and disaster relief (PPDR)
Interoperability
Intelligent transport systems (ITS)
Space considerations
Power considerations
Reconfiguration considerations
Amateur and amateur satellite systems
Other land mobile systems

37. References
[1] Software Defined Radio- A brief overview :Matthew N. O. Sadiku and Cajetan
M Akujuobi . IEEE potential OCTOBER/NOVEMBER 2004
[2] Software-defined GPS receiver on USRP-platform : Elizabeth A. Thompson
a,n, Nathan Clem a, Isaac Renninger a, Timothy Loos b . Journal of Network and
Computer Applications 35 (2012) 1352–1360
[3] Software Defined Radio , Brad Brannon, Analog Devices, Inc.
•
[4] Software defined radio in the land mobile, amateur and amateur satellite
services .
[5] A SOFTWARE DEFINED BY RADIO : Nark W. Chamberlain Harris
Corporation, RF Communications Division Rochester, New York
[6] Introduction to the Software-defined Radio Approach : A. F. B. Selva, A. L. G.
Reis, K. G. Lenzi, L. G. P. Meloni, Member, IEEE and S. E. Barbin, Member,
IEEE