CONCEPTS , BLOCK DIAGRAM, DESCRIPTION

1. SOFTWARE RADIO
By
Sanjana Prasad
1601RL01
4/12/20161

2. ∗ What is a Software Radio???
∗ Characteristics and benefits of Software Radio
∗ Model of a Software Radio
∗ Factors required for wider acceptance of a Software
Radio
∗ Design principles of a Software Radio
TOPICS
4/12/20162

3. ∗ The term Software Radio was coined by Joe Mitola in
1991
∗ Class of reprogrammable or reconfigurable radios
∗ Same piece of hardware can perform different
functions at different times.
∗ SDR forum definition(USR)
∗ Radio that accepts fully programmable traffic and
control information
∗ supports a broad range of frequencies, air-interfaces
and applications software
WHAT IS A SOFTWARE RADIO???
4/12/20163

4. 4/12/20164

5. ∗ The piece of hardware can be modified to perform
different functions at different times ,allowing the
hardware to be specifically tailored to the application at
hand
∗ Software radio can be used to encompass soft radios as
well. Software is confined to controlling the interface with
the network
∗ Hardware
∗ Amplifiers
∗ Filters
∗ Mixers
4/12/20165

6. ∗ Software
∗ Confined to controlling the interface with the network,
∗ stripping the headers and error correction codes from
the data packets and
∗ determining where the data packets need to be routed
based on header information.
∗ Represent a paradigm shift from fixed ,hardware –
intensive radios to multi-band, multi mode,software –
intensive radios
4/12/20166

7. ∗ The user can
∗ Switch from one interface to another in milliseconds
∗ Use GPS for location
∗ Store money using smartcard technology
∗ Watch a local broadcast station
∗ Receive a satellite transmission
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8. ∗ Implementation of software radio requires
∗ The digitization at the antenna ,allowing flexibility at the digital
domain
∗ Design of a completely flexible radio frequency (RF)front end for
handling a wide range of carrier frequencies and modulation
formats.
CHARACTERISTICS AND BENEFITS OF
SOFTWARE RADIO
4/12/20168

9. MODEL OF A SOFTWARE RADIO
Flexiblle
RF
Hardware
ADC
DAC
Channeliz
ation and
sample
rate
conversio
n
P Hardware
•FPGA
•DSP
•ASIC
Software
•Algorithms
•Middlewar
e
•Corba
•Virtual
radio
machine
Processing
Smart
antenna
IF
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10. ∗ Smart Antenna
∗ Provides a gain vs direction characteristic to minimize
interference,multipath and noise.
∗ Provides similar benefits for the transmitter
∗ Rxr(Superheterodyne)-digitization-as early-IF BAND
∗ Digital->analog->as late at transmitter using a DAC
∗ Superheterodyne reciever:
∗ Rf signal picked up by the antenna along with other
spurious/unwanted signals filtered ,amplified with a LNA
and mixed with a LO to an IF.
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11. ∗ No of stages-vary
∗ IF- mixed exactly to baseband
∗ Digitizing the signal with an ADC in the IF range-
eliminates the last stage
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12. ∗ Multi-functionality
∗ Global Mobility
∗ Compactness And Power Efficiency
∗ Ease Of Manufacture
∗ Ease Of Upgrades
FACTORS OF SOFTWARE RADIO
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13. Multi-functionality
∗support infinite variety of
service capabilities in a
system
∗ Bluetooth
∗ IEEE 802.11
Global mobility
∗ 2G
∗ IS-136
∗ GSM
∗ IS-95/CDMA 1
3G:HARMONISE ALL THE
STANDARDS
TRANSPARENCY HAS
FOSTERED THE GROWTH
OF THE
4/12/201613

14. Compactness And Power
Efficiency
∗ Velcro approach
∗ Separate silicon for each system
∗ Bulky,inefficient as number of
systems increases
∗ Used in multifunction,multi-
mode radios
Software Radio Approach:
∗ Compact
∗ Power Efficient Design- as
number of systems increases
∗ Since same piece of hardware
reused to implement multiple
systems and interfaces
Ease Of Manufacure
∗ RF components
∗ hard to standardise /varying
performance characteristics
∗ Optimization
∗ few years/delay product
information
∗ Digitisation of the signal –
result in fewer parts,reduced
inventory for the manufacturer
4/12/201614

15. • Current services-need to be
updated/new services need
to be updated
• Enhancements have to be
made without disruption of
current infrastructure
• flexible architecture->allows
improvments/additional
functionality
• Eg:VOCODER –High quality at
low bit rates
Ease Of Upgrades Users /Customers –
∗-expect services regardless of
geographical area
∗-Expect one device to utilize
services in all
regions(reconfiguring the rxr to
air-interface standards used in the
respective regions)
∗-Over the air updates-
∗ allow for speedy
implementation of software
upgrades and new features
4/12/201615

16. ∗ Systems Engineering
∗ RF Chain Planning
∗ Analog To Digital Conversion and Digital To Analog
Conversion Selection
∗ Software Architecture Selection
∗ Digital Signal Processing hardware architecture
selection
∗ Radio validation
DESIGN PRINCIPLES OF SOFTWARE
RADIO
4/12/201616

17. ∗ Understanding the constraints and requirements of the
communication link and the network protocol
->allocation of sufficient resources to establish the services
given the system s constraints and requirements
∗ Modulation and data type ->depends on range and
transmit power
∗ Well defined standard:routing protocol predetermined
∗ In a ideal software radio
∗ System parameters-change in real time
∗ Optimizing the active communications sessions-major
challenge
STEP 1-SYSTEMS ENGINEERING
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18. ∗ Ideal RF chain
∗ Incorporate simultaneous flexibility in selection of
power gain,bandwidth,center frequency,sensitivity,and
dynamic range
∗ Strict flexibility-impractical
∗ Trade-off s must be made
∗ Communication system constrained to selected military
or commercial bands->optimization problem simplified
∗ Compensation for power amplifier distortion or power
management of RF circuitry- digital domain
STEP-2 RF CHAIN PLANNING
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19. ∗ Difficult
∗ Selection-requires trading power consumption
,dynamic range and bandwidth
∗ Tied to rf reqirements for dynamic range and
frequency translation
∗ Channelisation requirements->selection of adc and
dac
∗ Post digitization techniques(based on multirate dsp)-
improve flexibility on the digitization stage
STEP 3-ADC AND DAC SELECTION
4/12/201619

20. ∗ Ensure maintainability,expandability,compatibility and
scalability for swr
∗ Consider latency and timing for the whole protocol stack
∗ Architecture-allow for hardware independence through
the use of middleware
∗ Middleware-Interface between application oriented
software and the hardware layer
∗ SOFTWARE
∗ aware of capabilities of the hardware(DSP and RF) at both
ends of the communications link to ensure compatibility
/maximum use of hardware resources
STEP4:SOFTWARE ARCHITECTURE
SELECTION
4/12/201620

21. ∗ Software Radio in a existing data infrastructure:
∗ Interface quickly and efficiently
∗ Security-important issue-to ensure software downloads-
legitimate
∗ Need to control issues regardless of protocol
∗ Attribute naming
∗ Error management
∗ Addressing
∗ Partioning radio functions -> objects help in portability ,
maintainence of the software
4/12/201621

22. ∗ Core DSP hardware –implemented through
Microprocessors
FPGA’S and/or
ASIC’s
∗ Microprocessors
∗ maximum flexibility,
∗ power consumption and
∗ lowest computational rate
∗ ASIC
∗ minimal flexibility
∗ lower power consumption
∗ highest computational rate
STEP 5:DSP HARDWARE ARCHITECTURE
SELECTION
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23. ∗ FPGA-lie between ASIC and a DSP
∗ Selection Of Core Computing Elements Depends On
∗ Algorithms
∗ Computational
∗ Throughput Requirements
Software radio will use all three core three core computing
requirements
4/12/201623

24. ∗ Most difficult step
∗ Ensure not only communication units operate correctly but also
that a glitch does not cause system-level failures
∗ Eg: interference caused by a software radio mobile unit-
adjacent bands
∗ Testing and validation steps -> minimize risk
∗ Structuring the software to link various modules with limitations
and deficiencies help in testing compatability of software modules
STEP7:RADIO VALIDATION
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25. ∗ Military radio
∗ Cellular services
∗ HF Transceivers
∗ FPGA
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APPLICATIONS OF SOFTWARE RADIO

26. 4/12/201626