SOFTWARE DEFINED RADIO

Kumar VimalCSE, VII SemSchool Of Engineering

A Presentation on

Preetha M. KuroopSchool Of Engineering

Under guidance of

Presented by

CONTENTSINTRODUCTION 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

What is Software Defined Radio(SDR)?

Introduction Methods Results Discussion

?To know SDR let's talk about a radio first!

BASIC BUILDING BLOCK OF A RADIO

Move signal from RF to baseband (original signal)

HOW?

Remove frequency componentsHOW?

Increase amplitude of signalmultiply by constant

Fourier Series Expansion

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“

Introduction Methods Results Discussion

Fourier Seriesdescribes the frequency content of periodic signals

The Theory Behind Radio Technology: Fourier Series

Different Time Domain signals have different harmonics (# and magnitude)

Introduction Methods Results Discussion

Example: Square Pulse, infinite # harmonics!

With 250 harmonics:

Gibbs phenomenonat discontinuity

Introduction Methods Results Discussion

Example: Sawtooth Wave

Introduction Methods Results Discussion

Example: Triangle Wave

Some TD signals are suited better for transmission than others (less harmonics)

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

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

Introduction Methods Results Discussion

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

Introduction Methods Results Discussion

What is Filtering?

Input Signal

Filter Response

Output Signal

Introduction Methods Results Discussion

Fourier Series: Continuous and DiscreteNice, but all of this was for continuous signals,What about discrete (digital) samples?

Fourier works in digital, too: Discrete Fourier Transform

Introduction Methods Results Discussion

A Radio?

Introduction Methods Results Discussion

A Conventional Radio: all in Analog

Introduction Methods Results Discussion

Issues With Conventional Radios

Introduction Methods Results Discussion

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.

What is SDR?

Introduction Methods Results Discussion

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"

What is SDR?

Introduction Methods Results Discussion

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“

SDR in easy words

Introduction Methods Results Discussion

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.

SDR EXPLAINED

Introduction Methods Results Discussion

History and Evaluation of SDR

Introduction Methods Results Discussion

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.

MOTIVATIONS

Introduction Methods Results Discussion

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.

How SDR works?

Introduction Methods Results Discussion

IDEAL SDR

Low Pass Filter

Analog to Digital Converter

Digital Signal Processor

Antenna

Block Diagram of Ideal SDR Receiver

Introduction Methods Results Discussion

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!

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!

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

Introduction Methods Results Discussion

SDR COCEPT

Introduction Methods Results Discussion

SDR COCEPT

Introduction Methods Results Discussion

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

SOFTWARE COMMON ARCHITECURE

Introduction Methods Results Discussion

“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

CORBA (Common Object Request Broker Architecture)

Introduction Methods Results Discussion

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

Tools Available

Introduction Methods Results Discussion

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 Interfacee.g. Sound interface ,USRP, Phi,Comedi etc.

Tools Available

Introduction Methods Results Discussion

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

Indian Software Defined Radio (ISDR)

Introduction Methods Results Discussion

RF-INTwo Section

BPF

RF AMP

R

R

C

C

/2 /2 OSC

P-AMP

Q-AMP

P

Q

0 DEG

90 DEG

Q

Q’

28.224MHz LO

BLOCK DIAGRAM OF ISDR

LPF

LPF

Indian Software Defined Radio (ISDR)

Introduction Methods Results Discussion

RF-INTwo Section

BPF

RF AMP

R

R

C

C

/2 /2 OSC

P-AMP

Q-AMP

P

Q

0 DEG

90 DEG

Q

Q’

28.224MHz LO

BLOCK DIAGRAM OF ISDR

LPF

LPF

Applications Of SDR Technology

Introduction Methods Results Discussion

SDR use in public safety

SDR use in the military

Commercial use of SDR

Benifits Of SDR Technology

Introduction Methods Results Discussion

User benefitsManufacturer benefitsWireless access systems (WAS) including radio local area networks (RLAN)Public protection and disaster relief (PPDR)InteroperabilityIntelligent transport systems (ITS) Space considerationsPower considerationsReconfiguration considerationsAmateur and amateur satellite systemsOther land mobile systems

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.

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[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