This document discusses software defined radio (SDR) technology. SDR uses software modules running on generic hardware like DSPs and microprocessors to implement radio functions rather than using dedicated hardware components. This allows radios to have their functionality redefined or upgraded through changes to its software. The document outlines the architecture of SDR systems and provides examples of SDR applications in areas like public safety, military uses, and commercial devices. It also discusses benefits such as flexibility and interoperability as well as challenges related to hardware limitations and software complexity. The future scope of SDR is seen to include adaptive radios and cognitive radios that can dynamically change their transmission behavior.

1. SOFTWARE DEFINED RADIO
Sandesh K A
4NI11EC047

2. OUTLINE
Introduction
Circuit design
Working
Applications
Benefits
Disadvantages
Future Scope

3. Introduction
What is SDR ?
It is a technology wherein software modules running on a
generic hardware platform consisting of DSPs and general
purpose microprocessors are used to implement radio
functions

4. WHY SDR ?
To produce a radio that can receive and transmit a new form of
radio protocol just by running new software.
A technique in which all the processing is done in software i.e.,
mixing, filtering, demodulation etc.
Used to implement different demodulation scheme and different
standards can be implemented in the same device.
Can be updated so that device doesn’t become obsolete with
time.

5. If software does everything what
is the role of hardware ?
Hardware is still needed for the RF front end and Analog to Digital
Convertor (ADC) and Digital to Analog converter (DAC).

6. Basic radio receiver unit

7. SDR ARCHITECTURE

8. HARDWARE
Low Cost
RTL2832U-Realtek SDR 24-1766 MHZ $10-$30
dongle
Medium cost
FunCube DonglePro 150kHz-2.05GHz $124.99-200
HackRF One 10MHz-0.6GHz £299
BladeRF 300MHz-3.8GHz $420-$460
High cost :
USRP! $707
USRPB200 70MHz-6GHz $675
UmTRX 300MHZ-3.8GHz $1500

9. SOFTWARE
Windows , Mac and Linux (Cross Platform)
GNU Radio Toolkit used by most SDR Open Source
(includes GNU Radio
Companion)
Linard Library used to interface Open Source
with hardware
Windows
SDR# spectrum viewer Open Source
HDSDR spectrum viewer Open Source

10. Mac and Linux
Gqrx spectrum viewer Open Source
Android
 SDR touch Free(trail)/$9.99 pro
 RTL2832U driver Driver for RTL-SDR
 ADSB Receiver Free
 ADS-8 on USB SDR RTl $1.50

11. 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.

12. SCA INTERFACE WITH SDR

13. 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.
 It has been chosen as the middleware layer of the Software
Communications Architecture (SCA), because of the wide
commercial availability of CORBA products and its industry
acceptance.
 Used to provide a cross-platform middleware service that simplifies
standardized client/server operations by hiding the actual
communication mechanisms under an object request broker
software bus

15. GNU radio software:

16. FM demodulation example in GNU Radio

17. Python auto generated code
from gnuradio import analog
from gnuradio import audio
from gnuradio import blocks
from gnuradio import eng_notation
from gnuradio import gr
from gnuradio import window
from gnuradio.eng_option import eng_option
from gnuradio.gr import firdes
from gnuradio.wxgui import fftsink2
from gnuradio.wxgui import forms
from gnuradio.wxgui import scopesink2
from grc_gnuradio import wxgui as grc_wxgui
from optparse import OptionParser
import wx
class dial_tone(grc_wxgui.top_block_gui):
def __init__(self):
grc_wxgui.top_block_gui.__init__(self, title="Dial Tone")
_icon_path = "/usr/share/icons/hicolor/32x32/apps/gnuradio-grc.png"
self.SetIcon(wx.Icon(_icon_path, wx.BITMAP_TYPE_ANY))
self.samp_rate = samp_rate = 32000
self.noise_slider = noise_slider = .005
_noise_slider_sizer = wx.BoxSizer(wx.VERTICAL)

18. Applications Of SDR Technology
Public safety
Cell phone technology
Military applications
Commercial use of SDR

19. Benefits Of SDR Technology
User benefits (personalized modulation scheme)
Manufacturer benefits
Interoperability
Intelligent transport systems (ITS)
Space considerations
Power considerations
Reconfiguration considerations
Other land mobile systems

20. Disadvantages of SDR:
 There are technology limits on achievable RF performances
 For very wide frequency coverage, the RF hardware may need to be built in
separate portions of circuitry dedicated to particular frequency ranges
 Two tone Inter Modulation Distortion(IMD)
 The choice of architecture depends on the available technology
 Complexity in using the software
 Software reliability may define overall radio reliability, rather than hardware
limitations

21. Future Scope
Adaptive Radio :
 Communication Systems which have means of measuring their own
performance and alter them to provide high performance. SDR helps to
provide high degree of freedom
Cognitive Radio:
Communication systems are aware of
their internal state and environment,
such as location and utilization on RF
frequency spectrum at that location.
They can make decisions about their radio
operating behavior by mapping that
information against predefined objectives.