5.1.2 What will the "next-generation" of SDR look like? - Amazon S3

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JOMO KENYATTA UNIVERSITY

OF AGRICULTURE AND TECHNOLOGY

P.O. BOX 62000
-
00200 NAIROBI

TEL: (067)
-
52181
-
4

FAX: (067)
-
52164

E
-
MAIL:
eee@jkuat.ac.ke


COLLEGE OF ENGINEERING


DEPARTMENT

OF ELECTRICAL AND ELECTRONICS ENGINEERING



FINAL YEAR PROJECT REPORT

TITLE:

A SOFTWARE DEFINED RADIO TRANSCEIVER

DONE BY:
Mwangi Samuel Wachira

REG. NO: E26


0
7
38
/
05

COURSE: BSC. ELECTRONIC AND
COMPUTER ENGINEERING.


SUPERVISOR:
MR ANANGI

ACADEMIC YEAR 2010/2011


Submitted to the Department of Electrical and Electronic Engineering in partial fulfillment for
the award of Bachelor of Science Degree in Electronic and Computer Engineering.

DECLARATION

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2


For sure
, this project is my original work and has not been submitted anywhere for the
award of a certificate, a diploma or a degree.
The project involves the implementation
of a Software Defined Radio Transciever.

This original work is present
ed as a
requirement to satisfy the board of examiners, academic year 2010/2011 for the award
of a Bachelor of Science (Electronics & Computer Engineering) degree from Jomo
Kenyatta University of Agriculture

and Technology
.


Mwangi Samuel Wachira

DATE:

…………
…………………. SIGNATURE:

………………………………



CERTIFICATION

This is to certify that the above named student carried out the project work detailed in this
report under my supervision.


MR ANANGI
.

DATE:

……………………………. SIGNATURE:

………………………………




















DEDICATION

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I dedicate this work to my parents, for all the support they have accorded me through

the ups
and downs of campus

life, and my sisters too.







































ACKNOWLEDGEMENT


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I want to thank
the staff of the Communication’s Commision of Kenya namely
Odipo
Godfrey and Njiriani Mwende for the technical advice

that
helped me become
interest
ed

in this
line of research
.

M
y wonderful

and loving

family for their kindness and assistance in all the lit
tle
ways.
Also Tony Parks
of
Kb9yig
.com

fo
r

allowing
me

to modify his
hardware kit
.

Much
a
pp
reciation goes to
Aketch of Octrinsic technologies for logistic
s

support.

Finally to all those who had a hand in this project in one way or the other.































ABSTRACT

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Software Defined Radio (SDR) and Cognitive Radio are future technologies that provide a more
flexible design for the wireless and mobile industry, and at the same time these technologies enable the
efficient utilization of freque
ncy resources. However, correct deployment of the technologies requires
radical changes in the regulatory framework of frequency management.

Software defined radio (SDR) is a flexible radio architecture programmed through software, which is
reconfigured
depending on the usage scenario. SDR consists of a programmable hardware base that is
controlled through software, where different parameters, like power level, frequency band and
modulation are changed/configured depending upon the environments in which u
sers move.
































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Abbreviations


SCA


Software Communication Architecture



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TABLE OF CONTENTS

DECLARATION…………………………………………………………………………..…......i.

CERTIFICATION……………………………………………………………………….….…....ii.

ACKNOWLEDGEMENTS...…………………………………………………………......…..…iii.

ABSTRACT……………………………………………………………………….………....….iv.

TABLE OF CONTENTS…………………………………………………………………………v.


CHAPTER 1: INTRODUCTON

1.

OVERVIEW

2.

PROBLEM STATEMENT

3.

OBJECTIVES

3.1.

General Objectives

3.2.

Specific Objectives

4.

JUSTIFICATION OF THE PROJECT

5.

LIMITATIONS


CHAPTER 2: LITERATURE REVIEW

1.

CAUSES OF ACCIDENTS

2.

HOW ULTRASOUND WORKS

3.

THE IDEAL WARNING SYSTEM


CHAPTER 3: METHODOLOGY

1.

SOFTWARE DESIGN

2.

FLOWCHARTS

3.

ACTUAL CODE


CHAPTER 1: INTRODUCTON

1.1

. OVERVIEW

A typical voice SDR
transmitter, such as might be used in mobile two
-
way radio or cellular
telephone communication, consists of the following stages. Items with asterisks represent
computer
-
controlled circuits whose parameters are determined by the programming
(software).



Mic
rophone

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Audio amplifier



Analog
-
to
-
digital converter (ADC) that converts the voice audio to
ASCII

data *



Modulator that impresses the ASCII intelligence onto a

radio
-
frequency (
RF
) carrier *



Series of amplifiers that boosts the RF carrier to the power level necessary for
transmission



Transmitting antenna

A typical receiv
er designed to intercept the above
-
described voice SDR signal would employ the
following stages, essentially reversing the transmitter's action.



Receiving antenna



super hete
rodyne

system that boosts incoming RF signal strength and converts it to a
constant frequency



Demodulator that separates the ASCII intelligence from the RF carrier *



Digital
-
to
-
analog converter (
DAC
)
-

generates a voice waveform from the ASCII data *



Audio amplifier



Speaker, earphone, or headset

We guarantee project completion since components are readily available in
Nairobi and by following our timeline strictly we shall be able to have an operational
QSD and GUI by September.



Most available radios have the transmission and reception parts a
s separate
modules but the transceiver implementation will reduce our task and allow us to focus
on the software element of our project.


A software
-
defined radio system, or SDR, is a radio communication system where components
that have typically been imp
lemented in hardware (e.g. mixers, filters, amplifiers, modulators
/demodulators, detectors, etc.) are instead implemented using software on a personal
computer or embedded computing devices. A basic SDR system may consist of a personal
computer equipped w
ith a sound card, or other analog
-
to
-
digital converter, preceded by some
form of RF front end. Significant amounts of signal processing are handed over to the general
-
purpose processor, rather than being done in special
-
purpose hardware. Such a design
prod
uces a radio that can receive and transmit widely different radio protocols (sometimes
referred to as a waveforms) based solely on the software used.

Software radios have significant utility for the military and cell phone services, both of which
must serv
e a wide variety of changing radio protocols in real time. A radio in which the RF
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
.


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1.2

. PROBLEM STATEMENT



The primary difficulty for regulators in overseeing the sharing of spectrum is to
minimize interference among devices operating on the same or nearby frequencies.



The issue of the day is how to get industry behind global

regulatory reform to promote
more efficient use of the electromagnetic spectrum.



In the current Hardware Defined Radio (HDR) era all the parameters in the radio access
interface are fixed parameters that cannot be changed unlike for SDR.



For regulators, S
DR has the potential to bring radical changes to how spectrum is used,
and therefore to the regulations that apply to radio communication systems..



1.3

. OBJECTIVES

1.3.1. GENERAL OBJECTIVES




To implement an SDR transceiver in VHF band.



To develop a highly
versatile SDR
-
PC interface that will provide frequency &
bandwidth calibration plus provide monitoring capabilities.



1.3.2. SPECIFIC OBJECTIVES


The specific objectives of this project are to:



To
design band specific Rx & Tx stages of a transceiver.



To use a
USB interface for control the radio system.



1.4. JUSTIFICATION OF THE PROJECT



For Radio Equipment Manufacturers & Economy , SDR Enables:

A family of radios to be implemented using a common platform architecture, allowing new
products to be more

quickly introduced into the market. Software to be reused across radio
"products", reducing development costs dramatically. Over
-
the
-
air or other remote
reprogramming, allowing "bug fixes" to occur while a radio is in service, thus reducing the time
and
costs associated with operation and maintenance.





For Radio Service Providers, SDR Enables:

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New features and capabilities to be added to existing infrastructure without requiring major
new capital expenditures, allowing service providers to future proof t
heir networks. The use of
a common radio platform for multiple markets, significantly reducing logistical support and
operating expenditures. Remote software downloads, through which capacity can be increased,
capability upgrades can be activated and new r
evenue generating features can be inserted.




For End Users
-

from business travelers to soldiers, SDR technology aims to:

Reduce costs in providing end
-
users with access to wireless communications


enabling them
to communicate with whomever they need, whe
never they need to and in whatever manner is
appropriate.




Environmental Impact, SDR technology aims to.

SDR radio based systems will require less power to operate due to fewer hardware
components and that makes them efficient.




Vision 2030 & SDR:

The Keny
an vision 2030 is an economic development plan by the government to develop
several different economic zones in various parts of the country. The plan aims to produce
annual economic growth rates of 10%. The targeted sectors are tourism, trade, agriculture
,
manufacturing, financial services and information technology. SDR will help improve service
delivery and reduce cost on the ICT sector.





CHAPTER 2: LITERATURE REVIEW


2.1
OVERVIEW OF SOFTWARE DEFINED RADIOS

An SDR is like a personal computer, where
the function of the computer is defined by its
software. In the same way, the functionality of the radio is defined by software loaded into the
radio. The hardware must be relatively generic but extremely broadband, with the software
controlling frequency,

modulation, channel bandwidth, security functions, and waveform
requirements. There is increasing interest in the technology for commercial applications.
Software upgrades may be sent via wireless networks.

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SDRs are “radios that provide software control
of a variety of modulation techniques, wide
-
band or narrow
-
band operation, communications security functions such as hopping, and
waveform requirements of current and evolving standards over a broad frequency range.” The
SDR should be able to store a large

number of waveforms and add new ones via software
download.

A typical voice SDR transmitter, such as might be used in mobile two
-
way radio or cellular
telephone communication, consists of the following stages. Items with asterisks represent
computer
-
contr
olled circuits whose parameters are determined by the programming
(software).



Microphone



Audio amplifier



Analog
-
to
-
digital converter (ADC) that converts the voice audio to
ASCII

data *



Modulator that impresses the ASCII intelligence onto a radio
-
frequency (
RF
) carrier *



Series of amplifiers that boosts the RF carrier to

the power level necessary for
transmission



Transmitting antenna

A typical receiver designed to intercept the above
-
described voice SDR signal would employ the
following stages, essentially reversing the transmitter's action.



Receiving antenna



super heterodyne

system that boosts incoming RF signal strength and converts it to a
constant frequency



Demodulator that separates the ASCII intelligence from the RF carrier *



Digital
-
t
o
-
analog converter (
DAC
)
-

generates a voice waveform from the ASCII data *



Audio amplifier



Speaker, earphone, or headset

We guarantee project completion since components are readily available in Nairobi and
by following our timeline strictly we shall be able to have an operational QSD and GUI by
September.


Most available radios have the transmission and reception parts as

separate modules
but the transceiver implementation will reduce our task and allow us to focus on the software
element of our project.


2.2
CURRENT RADIO SYSTEMS

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The ordinary radios that SDRs emulate differ widely in design and operating
characteristics.
The high
-
frequency (HF) spectrum from 1.6 to 30.0 MHz is still one of the most
widely used communications bands. But large power amplifiers, antennas, and robust antenna
matching circuitry are needed for long
-
range communications, and such components are n
ot
well suited to extended battery life.

Due to signal congestion in the over
-
crowded HF band, HF radios must often compete
with interference from other transmitters. To combat interfering signals, HF radio front ends
are usually designed with high interce
pt points and employ sharp cut
-
off filters to eliminate
unwanted signals. Information bandwidths are limited, often only 3 kHz wide, requiring stable
frequency synthesizers in the radio’s front
-
end circuitry along with narrow intermediate
-
frequency (IF) fi
lters so that transmitted signals do not spill into adjacent bands. As frequencies
increase (and wavelengths diminish), the range of radios decreases but so also does the size of
the antenna, the transmit amplifier, and the impedance
-
matching circuitry for

very
-
high
-
frequency (VHF) radios in the range 30 to 225 MHz Suitable for medium propagation distances,
VHF radios have wider channels and IFs (to 25 kHz) than HF radios in order to support higher
data rates. For VHF radios, frequency congestion and the co
-
location of interference signals are
similar to the problems faced by HF radios, requiring stable front
-
end frequency synthesizers
and tight filters. To maintain data integrity, VHF radios require extremely linear amplifiers for
transmission, although the

inefficiencies of Class A amplifiers result in shortened battery life.
Moving up in frequency, ultrahigh
-
frequency (UHF) radios span 225 to 512 MHz To use smaller
antennas in tactical designs, UHF radios require relatively high
-
power transmit amplifiers a
nd
low
-
noise amplifiers (LNAs) prior to the receive electronics. Often, directional antennas are
employed with UHF radios to increase system gain and data rates on both receive and transmit
links. For high data throughput, UHF radio hardware must provide f
ast transmit
-
to
-
receive
switching and fast frequency hop rates, requiring the use of agile frequency synthesizers such
as direct
-
digital
-
synthesizer (DDS) sources. Often the choice of radio synthesizer is a choice
between switching speed and phase noise.


2.
3

THE SOFTWARE SOLUTION


The three types of radio explained in the section 2.2 above, along with coverage of
higher frequencies, are encompassed in an SDR. While current hardware SDR designs vary, the
software portion of the radio is clearly defined by t
he Software Communications Architecture
(SCA).

In an SDR, the software defines radio operation from the physical layer through higher
-
level
protocol layers. The SCA is an open
-
architecture framework that aims for the portability,
reusability, and scalabili
ty of the software and hardware developed under its guidelines to
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ensure that radios and software from one vendor work with the hardware and software from
another vendor.

An ideal SDR receiver would digitize signals from the antenna so that received
inform
ation spends the majority of its time in the digital realm. But current analog
-
to
-
digital
converter (ADC) technology lacks the combination of bandwidth and bit resolution needed for
this “direct
-
to
-
digital” receiver architecture. As a result, the analog fr
ont ends of SDRs still
resemble the super heterodyne architectures of their analog HF, VHF, and UHF counterparts,
albeit with the possibility of all three bands being handled by a single set of components

Analog signals are down
-
converted in frequency in a
n SDR’s receiver front end, then
converted to a digital IF via an ADC. Switchable analog filters select a desired radio channel, but
filtering and signal processing at IF and baseband are implemented by means of digital signal
processing (DSP) and sharply
defined digital filters to remove images and interference. In the
transmitter, digital baseband/IF signals are converted to the analog realm by means of digital
-
to
-
analog converters (DACs) and subsequently translated to the desired transmit frequencies by
means of analog frequency up converters.


2.
3
.1.
DEVELOPMENT OF
SDR

TECHNOLOGY IN

THE 2
1ST

CENTURY


The SDR Forum commissioned a number of research reports in 2006 to evaluate the adoption
of SDR technologies in various markets. The results of these studies demonstrated that, in
certain markets, SDR is moving beyond the innovators and early adopters as d
efined by
Geoffrey Moore in “Crossing the Chasm” into the early majority phase defining the mainstream
market2. In this phase, adopters select a technology not because it is innovative or visionary
but because it has been shown to successfully solve a prob
lem within their specific market.

Examples of SDR adoption illustrating the transition to the mainstream are abundant:

• Thousands of software defined radios have been successfully deployed in defense
applications

• Cellular infrastructure systems are inc
reasingly using programmable processing devices to
create “common platform” or “multibandmultiprotocol” base stations supporting multiple
cellular infrastructure standards

• Cellular handsets are increasingly utilizing System on Chip (SoC) devices that in
corporate
programmable “DSP Cores” to support the baseband signal/modem processing

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• Satellite “modems” in the commercial and defense markets make pervasive use of
programmable processing devices for intermediate frequency and baseband signal processing

Wh
ile these types of systems are often not marketed as “SDR’s”, they utilize and benefit from
SDR technologies to solve market specific problems such as; cost of development, cost of
production, cost of upgrades and maintenance, time to market in supporting
new and evolving
air interface standards, or problems associated with network interoperability.

In addition, the SDR Forum’s market and technology studies have shown that cost effective
radio frequency technologies supporting the operation of software defi
ned radios over a broad
spectral range have begun to mature, allowing for the first time the use of software defined
radio as an enabling technology for dynamic spectrum access systems with cognitive or smart
radio functionality. This trend is expected to
continue over the next several years, allowing SDR
to finally achieve the defined vision of reducing costs in providing end
-
users with access to
ubiquitous wireless communications


enabling them to communicate with whomever they
need, whenever they need t
o and in whatever manner is appropriate



2.3.
2
.
SDR POLICY


The primary difficulty for regulators in overseeing the sharing of spectrum is to minimize
interference among devices operating on the same or nearby frequencies. It was primarily to
prevent inte
rference to wireless messages that spectrum licensing was first instituted. Today, a
number of administrative and technological methods are available to minimize interference of
wireless transmissions. In theory, all spectrum bands can be shared if interfe
rence can be
managed.


The issue of the day is how to get industry behind global regulatory reform to promote
more efficient use of the electromagnetic spectrum. Groups such as the SDR Forum and IEEE
Standards Coordinating Committee 41 (SCC41) (Dynamic Sp
ectrum Access Networks) are doing
what they can, but to date, they still lack a focused commercial approach.




ITU is the leading United Nations agency for information and communication
technologies. As the global focal point for governments and the private sector, ITU's role in
helping the world communicate spans 3 core sectors:
radio communication
, standardizatio
n
and development. ITU also organizes TELECOM events and was the lead organizing agency of
the World Summit on the Information Society. The ITU
Radio communication

Sector (ITU
-
R)
plays a vital role in the global management of the radio
-
frequency spectrum a
nd satellite orbits
-

limited natural resources which are increasingly in demand from a large and growing number
of services such as fixed, mobile, broadcasting, amateur, space research, emergency
telecommunications, meteorology, global positioning systems
, environmental monitoring and
communication services
-

that ensure safety of life on land, at sea and in the skies.In the US and
the European Union, recent regulatory innovations have opened the door to SDR devices.
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Nevertheless, further reform, especiall
y in the area of spectrum policy, will be necessary before
the maximum benefits from SDR can be realized.



2.
3
.
3
.
FIELDS IN WHI
CH SDR

TECHNOLOGY IS EMPLOYED


2.
3.
3
.
1
.
The
Military


The Joi
nt Tactical Radio System (JTRS)

was initiated to improve and consolidate the
Services' pursuit of separable solutions to replace legacy radios within the US Department of
Defense Inventory. The JTRS program has evolved from separate radio replacement programs
to an integrated effort to
network multiple weapons system platforms and forward combat
units where it matters most
-

the last tactical mile. JTRS will link the power of the Global
Information Grid to the
war fighter

in applying fire effects and achieving overall battlefield
superio
rity.


The concept of an SDR was developed by the military to meet the requirements for
reliable and secure communications across different branches of the armed forces.

In the military, SDR applications are emerging rapidly as the technology advances to
e
nable their effective use. SDR solvesthe existing incompatibilities between the command and
control radio systems of the various branches of the armed services as well as with the
communications systems of allied and coalition forces, enabling all units to

work together as a
single team. Future SDRs will seamlessly operate with the latest single
-
channel ground and
airborne radio system (SINCGARS) units, for example.

One of the best known of SDR suppliers to both military and civilian customers is the RF
Com
munications Division of Harris Corporation (
www.harris.com
). The company’s single
-
channel RF
-
300M
-
HH JTRS SCA
-
enabled hand
-
held radio is programmable with a variety of
platforms including SINCGARS, HAVEQUICK II, VHF/UH
F AM and FM waveforms.


2.
3
.
3
.2.
Mobile Communication
Systems


It enables a smoother guaranteed evolution path to future technologies e.g. same radio network
for both GSM and UMTS. Thus, use of SDRs drastically reduces CAPEX & OPEX in new hardware when
upg
rading to UMTS or LTE.

Furthermore, use of SDRs in mobile networks allows for off
-
site maintenance and/or upgrade of
sites in effect ensuring no interruption of services or negative impact on customer experience.

Deployment of this equipment also leads to
significant energy savings and thus cuts large
amounts of CO2 emissions as well as tons of e
-
waste that result due to network upgrades.

Overall, this is an evolutionary piece of equipment to the telecom industry not only because of
financial savings but al
so due to its flexibility to tailor a network in real time while at the same time
remaining “green” (environmentally friendly).

CSL, the largest GSM operator in Hong Kong in terms of subscribers and revenue,
announced that it has

20 active and fully operational LTE (Long Term Evolution) cell sites rolled
out in Hong Kong using SDR (software
-
defined radio) base stations supplied by ZTE. CEO,
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Christian Daigneault, said the trials were showing peak download speeds upwards of 100Mbps
o
n the streets of Hong Kong using USB modems.

"Maybe we have to revisit the time in which
LTE will be commercially available and rolled out in networks across the world," he said in
statement.


2.
3
.
3
.3.
Disaster

Management



2.
3
.
3
.4
.
GSM Base Stations On
SDR

In the current Hardware Defined Radio (HDR) era all the parameters in the radio access
interface are fixed parameters that cannot be changed. A GSM interface is designed for the
GSM band, so a GSM phone cannot be reconfigure
d to work in a CDMA environm
ent
.
Therefore, using the analogy of the pre
-
PC era to the current HDR era, there are a number of
specialized wireless devices for specialized tasks. The SDR platform will, like PCs, create the
possibility of changing the character of the device depending
on the application and by
downloading different software modules.




2.
4
. CHALLENGES FACING SDR TECHNOLOGY


Currently the direct digital synthesizers (DDSes) that derive the internal local oscillator signals used to
tune SDR receiver hardware are
notorious for generating spurious RF byproducts i
n the passband of the
receiver.

These spurs, as they are called, can mask weak signals and make entire band segments in the
RF spectrum useless.


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What are the remaining technical/market challenges for SDR?


1.

The main technical/market challenges facing SDR today is that the framework and middleware
defined to support SDR systems (SCA framework and CORBA middleware) is considered to be very
resource intensive and, as such, does not fit well into the commercia
l communications market where
the demand for highly cost
-
efficient systems is high. So what the SDR community needs to drive is to
focus and define the specs for less resource intensive framework and middleware that can still help
users achieve maximum sof
tware defined capabilities in their radio systems.


2.

Adoption of industry
-
wide software standards for SDR can help ensure customer acceptance by
yielding compatible and competitive solutions that are available from a range of vendors. At the same
time, i
nnovative software solutions developed by leading vendors must be protected in order to provide
some return on investment. Finding a business model to create a balance point between these two
conflicting issues is the greatest challenge for SDR.


3.

SDR ha
s already been deployed in military tactical radios and has been fielded successfully. Many
commercial radios have also moved much of the radio functionality into DSP (embedded DSP and
FPGA/ASIC). The current challenges are moving into the areas of cogniti
ve radio. Being able to detect
the operating environment and switching between different communication PHYs on the fly allows a
radio to function anywhere at any time. Also possibly being able to optimize the needed signal BW for a
given link would allow f
or efficient use of available spectrum.


4.
From a technical point of view, the bottle neck is usually the ADC in the receive path. In the transmit
path, the limitation is often the DAC and modulator, however, this is
dependent

on the waveforms
necessary
to be transmitted. From a marketing point of view, the challenge of a full SDR system is the
increased cost associated with additional FPGA and DSP capacity. Dedicated ASICS are always cheaper
and the flexibility always comes with a cost. In addition, a sy
stem designed with SDR in mind often costs
more because the RF design must meet the worst anticipated requirements cause over design for all
others. This poses a challenge to meet both the performance requirements as well as the cost objectives


CHAPTER
3
:

METHODOLOGY

3
.1
Software Design

3.1.
0
.
INTRODUCTION

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From the outset w
e considered various approaches in implementing this SDR project
and
were able to determine, after some significant setbacks, that
the most
v
iable option was to
obtain a working radio

hardware

operating at between
3.5 MHz

to

7.5

MHz

and modify it to
operate from 25 MHz to 30Mhz.

We then configured our own software system to
match the
said frequency range.
This allowed us to reach the VHF band with a student friendly design
approach.

Th
e other two paths we could have
selected
a
re detailed in the challenges section of
the report.


3.1.1. DESIGN OF THE CAS CIRCUIT

The fundamental objective of the SCA is to provide a common software infrastructure for

managing
radio systems. Although
software comprises a significant part of most recent

radios


thus enabling new
capabilities and functions to be added to the radio at some future

times


the software is loaded and
controlled through proprietary mechanisms and each radio

manufacturer typi
cally employs a unique
infrastructure or architecture. A software defined

radio, as interpreted here, refers to a class of radios,
the capabilities of which are not simply

provided by software but utilize an infrastructure that supports
interchangeable com
ponents

as well as functionality. The SCA specification

describes

a collection of
components, the configuration of the components, and the assembly

of the components into a
functional waveform application on a radio system. Taken

together, these form an in
frastructure for
defining and constructing a

software defined radio

system.

3.1.1. GENERAL TRANSCEIVER
EXPLANATION

Figure below
illustrates the abstraction space of bandwidth versus waveform abstraction. At

the lowest
level is a set of hardware that
provides the actual processing of the waveform

and support software. The
processing is provided by one of four options, General Purpose

Processor (GPP), Digital Signal Processor
(DSP), Field Programmable Gate Array (FPGA),

and Application Specific Integrat
ed Circuit (ASIC). The
ASIC is typically not considered

part of the solution set within a software radio because, once
programmed, it cannot be

modified after deployment


one of the fundamental tenets of a software
radio.1

The aim of Figure 1.1 is to illu
strate the two orthogonal perspectives of software radio

design.
The waveform design starts as a set of requirements, simulation, mathematical


m
odel

, or some other
conceptual representation
.







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As the waveform progresses from design

to implementat
ion, the capabilities of the waveform, in terms
of throughput and capacity,

typically drive the implementation to a high
-
level language for deployment
on a GPP

or DSP. Higher throughput demands drive the deployment towards and FPGA or an

ASIC.

The GPP proc
essor typically provides the management and control services for the system.

Overlaid on top of the processor is an operating system and, integrated with the operating

system, is a
collection of software that provides the run
-
time infrastructure for the ra
dio

set
. The infrastructure, in
SCA terms, is called the Core Framework. On top of the Core Framework sits the waveform and other
applications.


Software Radio Aspects


A software radio system can be viewed through one of four perspectives or aspects. Each

aspect forms a
functional grouping of objects and services provided by the radio system.

This can be shown by the
diagram shown below









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Software Aspects are best summarized as:




Hardware


This aspect describes the physical set of devices and co
mponents that

comprise the
radio set.



Software


This aspect defines the set of services and interfaces through which all

waveform
applications must interface to the underlying hardware.



Application


This aspect defines the application and service layer.
All waveforms and

common
services execute in this aspect.



User


This aspect is the view through which the user interacts with the radio set. There

are two
basic modes of interaction within this aspect. The user is either performing radio

control
operation
s, e.g. setting system parameters, or performing application control and

data transfer,
e.g. setting the gain parameter for a specific waveform instance.

The SCA can be viewed as one realization of the Software Infrastructure aspect with

some parts within
the Applications and Services aspect. It defines a logical infrastructure

for management and abstraction
of physical hardware components, a standard set of

abstractions for software components that form the
digital processing portion of a waveform

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The Soft
ware Communications Architecture

Any new concept or technology has a learning curve as
sociated with it and the SCA is
no exception. The
SCA defines a software infrastructure f
or the management, control, and
configuration of a software
defined radio. It doe
s not man
date any specific architecture,
design, or implementation for the radio
system hardware or waveform applicati
on. Before
launching into the detailed discussion of the SCA, it is
advisab
le to spend a short bit of time
providing some background data
and explanation on what the
SCA
is, and is not, the history
of its evolution, and the reasons why you would (or would
not) want to apply
the SCA to
your system.

The SCA is based on several related technologies: Object
-
Oriented (OO) techniques in

software
engineering, the Common Object Request Broker Architecture (CORBA), and the

CORBA Components
Model (CCM). Object
-
oriented languages have been around for a

number of years from Simula in the
late 1960s, Smalltalk and Flavors in the early 1980s, to

current o
bject
-
oriented languages such as C
++
,
Python, Ruby, and Java, to name a few.

As systems evolved towards distributed architectures and a
client
-
server model, CORBA

evolved as an industry standard for describing the interfaces provided or
used by two

compone
nts using a pseudo
-
code called an Interface Definition Language (IDL). IDL

provided the means for specifying the available interfaces and, through the IDL ‘compiler’,

generated
source code that is compiled into each of the applications. The code generated

includes the support
routines necessary to support remote procedure calls between processes

on the same computer and
between computers, i.e. in a distributed environment. Thus, the

developer was freed from the drudgery
of writing low
-
level, inter
-
process c
ommunications

code and, more importantly, CORBA code built by
one individual could interoperate with

code built by another individual, the only requirement being that
both the author of the

client application and the server application use the same IDL. Th
is was an
important step

forward in the ability to develop modular software while encapsulating the internal logic

and requiring only that each of the developers agree on a set of IDL.

Although the CORBA technology provided several important advances, it
became apparent

that
the mechanism by which systems were deployed was still dependent on manual

configuration. The CCM
evolved to address the need for specifying the requirements for

deploying a set of application software
by describing what resources were

required to deploy

the system successfully on a set of hardware. The
method for describing the components of

a system and the related deployment requirements is through
a set of eXtensible Markup

Language (XML) files. XML is a text
-
based language that uti
lizes tags to define
items,

their attributes, and values. This CCM XML was the genesis of the SCA Domain Profile

XML.

With this brief summary of background information

and foundation technology as a
backdrop, the next
sections provide a summary of what th
e

SCA is, is not, why you would
(or would not) want to use it, and
a brief history of its evolution.




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The Evolution of the SCA


The United States military was (and is) facing an increasingly critical need to support

communications for multiple missions, r
apid deployment, diverse mission scenarios and

objectives,
increased interoperability, and to reduce the cost of operations. One of the primary obstacles to
meeting these challenges was that the bulk of the radio systems were

predominantly hardware
-
based,
limited to those waveforms that were designed into the

system, and incapable of being upgraded or
adding new waveforms without significant cost

due to hardware re
-
design.


Concurrently, over the past two decades, the capabilities of processors have
increased

dramatically, special purpose processors such as DSPs and FPGAs have become commonly

available, and
the speed and resolution of Analog to Digital and Digital to Analog circuits

have steadily increased. The
result is that more of the waveform sign
al processing that once

was exclusively the preserve of the
analog domain was migrating into the digital domain

implemented in software. Early experiments in
software
-
based radios such as SpeakEasy

showed that there were significant benefits to be gained b
y
moving towards a softwarebased

architecture. Many of the radio manufacturers had already started
down the path

of implementing core signal processing components in software. Early multi
-
channel
radio

systems developed in the 1990s, such as the Joint Comb
at Information Terminal (JCIT) and

the
Digital Modular Radio (DMR), provided a software infrastructure for the management

of radio
resources.

With the need to enhance reconfigurability, support multiple missions, and reduce longterm

operations and maintena
nce costs as a background, the Joint Tactical Radio System

(JTRS) Joint Program
Office (JPO) was formed to develop a new family of software
-
based,

reconfigurable, radio systems. One
of the first activities was to define a common software

infrastructure tha
t would be applied to this new
family of radio systems. Thus, the SCA

was born.



What is the SCA?

The main purpose of the SCA specification is to define the Operating Environment (OE)

software, also
commonly referred to as the Core Framework, which implem
ents the core

management, deployment,
configuration, and control of the radio system and the applications

that run on the radio platform. In
order to provide a common reference for describing what

the SCA is and isn’t, it is useful to refer back to
the int
roduction provided with the SCA

specification.

The Software Communication Architecture (SCA) specification is published by the

Joint Tactical Radio
System (JTRS) Joint Program Office (JPO). This program office

was established to pursue the
development of
future communication systems, capturing

the benefits of the technology advances of
recent years, which are expected to

greatly enhance interoperability of communication systems and
reduce development

and deployment costs. The goals set for the JTRS program

are:




greatly increased operational flexibility and interoperability of globally deployed systems;



reduced supportability costs;



upgradeability in terms of easy technology insertion and capability upgrades; and reduced
system acquisition and operation
cost.


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In order to achieve these goals, the SCA has been structured to


provide for portability of applications
software between different SCA

implementations;


leverage commercial standards to reduce
development cost;

reduce development time of new
waveforms through the ability to reuse design

modules; and

build on evolving commercial frameworks and architectures.




3.2.2.

FLOWCHART
:

SYSTEM FLOWCHART


3.2.3. FULL

CODE

WITH COMMENTS
:

It is

worth noting that the code presented is for the digital signal processing part of the program
since this was the only part of the code that got to be modified. The rest of the running
program was from an open source alternative that was presented to the r
esearchers by the
hardware developers.













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Screen Shots


Modification of the Si570 Local Oscillator













Figure
1

This aids in the detection of the Crystal Oscillator

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Figure
2
This
shows the tuning of the Crystal Oscillator


The Final Interface


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5.0 CONCLUSION

5.1
.1

What
we
would like RF designers to understand about SDR?


1.

SDR does not eliminate the need for RF design. In fact, SDR will in all likelihood place new challenges
in the path of RF designers to create wide band very linear RF front ends for SDR platforms. It is also
important for RF designers to start moving out
of their comfort zone to develop competencies in digital
signal processing and firmware development for FPGAs. One can no longer design RF or DSP in isolation
because SDRs, particularly cognitive SDRs, require a high degree of integration between RF and DS
P.


2.
There are various implementations of SDR, many of which are already being adopted into mainstream
designs. For example, many communication system designers are already designing wideband
transceivers that can be used with a wide variety of waveforms.

Often these are not changed on the fly
as the classic definition of SDR goes. Instead, one system is designed and manufactured for a wide
variety of waveforms to gain economies of scale. During alignment, calibration, or even in the field, the
waveforms f
or the particular standard are 'installed'. These waveforms are determined by a
combination of FPGA configurations and DSP code that may evolve over time. Because the basic
transceiver does include the flexibility to deal with a wide range of waveforms, as

the waveform evolves
or in fact changes, these may be uploaded as a combination of firmware and software changes to
accommodate the new waveforms. Of course the down side is that the transceiver must be designed to
allow for the widest dynamic range.


3.

The power, space and cost tradeoffs involved in a true SDR solution. While semiconductor vendors,
like TI, are working to reduce these implications, we still see these as immediate challenges to a truly
software defined radio card RF design.


4.

RF desig
ners often struggle deciding where to draw the line between analog and digital processing
tasks when architecting a specific radio system. SDR still requires prudent design of the analog RF
sections before the signal is digitized to ensure that subsequent
digital signal processing stages can
successfully extract the transmitted signal. Successful allocation of tasks mandates a careful tradeoff
analysis of costs and performance benefits by experts in both RF and DSP domains.

5.1.2
What will the "next
-
generat
ion" of SDR look like?


1.
Next gen SDR will largely be transparent to the end user. Just as many systems today incorporate
many SDR techniques, the user is often unaware of this fact. A well designed system will therefore be
transparent to the end user. F
rom the operator point of view, the ultimate cost of operation should be
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much lower in that one piece of hardware may be used for a much longer period of time with sufficient
resources to support field upgrades in a manner that will extend the usefulness o
f the equipment.


2.

SDR technology will move even closer to the antenna. Obviously, higher speed A/D converters and
faster DSP engines will allow wideband software signal processing. But the key enabler for this trend will
be innovative designs for progra
mmable RF filters preceding the wideband SDR digitizers.


3.

The next generation SDR is a full software controlled radio whereby even the frequency of operation
is programmable to a wide range with modulators, mixers and tuners capable of covering wide ran
ge of
frequencies. There is an increasing trend toward zero IF (or direct conversion) radio which will become
standard. This will be followed with cognitive radios that can sample the wireless interfaces and adapt
the radio to the frequency and modulation
scheme with the best efficiency of operation.


4.

The holy grail of SDR is to have a DC to daylight analog front end with digital down
-
conversion and
sampling of the signal at the antenna. While we are not there yet, the next generation of SDR will have
h
igher dynamic range A/D and D/A converters operating at GSPS rates for mA of current consumption.
These will be incorporated into single
chip

designs with all of the filtering, demodulation, decoding, and
equalization contained onboard.



5.2 REFERENCES

gs
m adaptive array trial results using an sdr cellular base station

http://www.sdrforum.org/pages/sdr05/5.4%20Reconfigurable%20Antenna/5.4
-
05%20Komara.pdf

tests and trials of software
-
defined and cognitive radio in ireland

http://groups.sdrforum.org/download.php?sid=1160
\



field trials of an all
-
software gsm basestation

http://www.sdrforum.org/pages/sdr03/papers/Applications/AP2
-
003
-
Steinheider.pdf


1.

www.zte.com.cn

2.

www.wirelessinnovation.com

3.

www.sdrforum.org


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4.

www.wikipedia.com

5.

www.ieee.org

6.

www.sdr
-
radio.com

7.

www.etsi.org