Software Defined Radio


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Software Defined Radio

  1. 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. 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. 3. Introduction Methods Results Discussion What is Software Defined Radio(SDR)? ? To know SDR let's talk about a radio first!
  4. 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. 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. 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. 7. Introduction Methods Results Example: Square Pulse, infinite # harmonics! With 250 harmonics: Gibbs phenomenon at discontinuity Discussion
  8. 8. Introduction Methods Example: Sawtooth Wave Results Discussion
  9. 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. 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. 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. 12. Introduction Methods Results Discussion What is Filtering? Input Signal Filter Response Output Signal
  13. 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. 14. Introduction A Radio? Methods Results Discussion
  15. 15. Introduction Methods A Conventional Radio: all in Analog Results Discussion
  16. 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. 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. 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. 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. 20. Introduction Methods Results SDR EXPLAINED Discussion
  21. 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. 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. 23. Introduction Methods Results How SDR works? Discussion
  24. 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. 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. 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. 27. Introduction Methods SDR COCEPT Results Discussion
  28. 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. 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. 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. 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. 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. 33. Introduction Methods Results Discussion Indian Software Defined Radio (ISDR) P P-AM P L P R F C 0 D E G Two Section BPF RF-IN Q /2 RF AMP R Q-AMP L P F Q C 90 D E G BLOCK DIAGRAM OF ISDR /2 OSC Q ’ 28.224MHz LO
  34. 34. Introduction Methods Results Discussion Indian Software Defined Radio (ISDR) P P-AM P L P R F C 0 D E G Two Section BPF RF-IN Q /2 RF AMP R Q-AMP L P F Q C 90 D E G BLOCK DIAGRAM OF ISDR /2 OSC Q ’ 28.224MHz LO
  35. 35. Introduction Methods Results Discussion Applications Of SDR Technology SDR use in public safety SDR use in the military Commercial use of SDR
  36. 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. 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