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From Analog to Software Defined: A History of the Radio

From Analog to Software Defined: A History of the Radio. Dr. Roland Kempter kempter@ece.utah.edu. Organization. The History of Radio Communication (incomplete) Important Concepts: Filtering and Modulation Background: Fourier Series Expansion SIMULINK Demo

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From Analog to Software Defined: A History of the Radio

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  1. From Analog to Software Defined:A History of the Radio Dr. Roland Kempter kempter@ece.utah.edu

  2. Organization The History of Radio Communication (incomplete) Important Concepts: Filtering and Modulation Background: Fourier Series Expansion SIMULINK Demo From Analog to Digital: Software Defined Radio Programming Software Defined Radios

  3. History of the Radio: James C. Maxwell 1861-1865: James Clerk Maxwell experiments with electromagnetic waves 1873: describes the propagation of electromagnetic waves in his paper “A Dynamical Theory of the Electromagnetic Field”

  4. Wireless Radio Begins: Nikola Tesla 1893: Tesla gives public demonstration of wireless radio communicationat St. Louis, Missouri. He describes in detail the principles of radio communication.

  5. 1909: Marconi and Karl Ferdinand Braun win Nobel Prize in Physics for "contributions to the development of wireless telegraphy" Wireless Radio Begins: Guglielmo Marconi and K. F. Braun 1896: G. Marconi is awarded a patent for radio: Improvements in Transmitting Electrical Impulses and Signals and in Apparatus There-for 1897: Marconiestablishes a radio station on the Isle of Wight (England)

  6. The History of the Radio

  7. Better Sound Quality: FM Radio 1933: Edwin H. Armstrong patents FM radio (better quality than AM) 1940s: analog television transmissions start in North America and Europe.

  8. However, radio itself still “analog” up to the decoder stage The History of the Radio: the 21st century Internet radio Streaming Internet connection, no RF, IF, etc. Digital Audio Broadcasting (DAB) alternative to FM Satellite Radio XM Radio, Sirius Satellite Radio etc… Going from analog “payload” to digital “payload”

  9. Increase amplitude of signal multiply by constant Move signal from RF to baseband (original signal) HOW? Remove frequency components HOW? Fourier Series Expansion The Fundamental Blocks in a Radio

  10. 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 Fourier applied it to to problems of heat flow. 1824: gases in the atmosphere increase the surface temperature of the Earth. Fourier described the greenhouse effect!

  11. Different Time Domain signals have different harmonics (# and magnitude) The Theory Behind Radio Technology: Fourier Series Fourier Series describes the frequency content of periodic signals

  12. With 250 harmonics: Gibbsphenomenon atdiscontinuity Example: Square Pulse, infinite # harmonics!

  13. Example: Sawtooth Wave

  14. Some TD signals are suited better fortransmission than others (less harmonics) 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

  15. (right) logarithm of the magnitude of the FT of Fourier Courtesy of Thomas F. Weiss
Massachusetts Institute of Technology Example: Fourier Transform

  16. 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 What is Modulation Modulation: multiplication of baseband signal by a carrier wave

  17. Fundamental Blocks: Why is Modulation Necessary? At least 2 reasons: • different signals from different systems do not interfere • Example: - broad band cable services • - Public TV and Radio (wireless services) • move the payload signal to frequency where it can be • transmitted most easily • Problem: - signal attenuation in wires • - free space signal attenuation

  18. What is Filtering? Input Signal Filter Response Output Signal

  19. Modulate: x fc Demodulate: x fc Filter: Modulation and Demodulation

  20. Fourier works in digital, too: Discrete Fourier Transform Fourier Series: Continuous and Discrete Nice, but all of this was for continuous signals, What about discrete (digital) samples?

  21. SIMULINK DEMO BPSK Radio

  22. A Radio?

  23. A Conventional Radio: all in Analog

  24. Software Defined Radio: RX Signals are digitizedimmediatelyafter the LNA and then processed entirely in software, flexible TX vice versa New Paradigm: Software Defined Radio (SDR)

  25. A Radio!

  26. SDR is Real! 23 November 2004: FCC approves the first SDR device in the United States. If radio changes behavior, no more re-approval necessary! VANU Inc., ANYWAVE cellular base station: HP proliant server, ADC/DAC, running Linux, can act as a GSM, CDMA and UMTS basestation through software updates

  27. But Different people have different brains! Different Hardware, simple downloads won’t work! Various manufacturers of SDR boards  various flavors of hardware, on-the-flyreconfigurationrequires specific configuration files!Infeasible! Describe to the target (brain) what to do: Give presentations instead of .exe files Programming Software Defined Radios: Download? Trinity: Operator, I need a pilot program for a V-212 helicopter!

  28. State-of-the-art: SCA, Software Communication Architecture CORBA, XML with Object Request Broker (ORB) middleware Future: Ontology-based programming languages,“describe” to the board what to do, board (compiler) figures out how and if possible Benefits: Easier board programming, do it once for different architectures Enable reconfiguration “on-the-fly”, download of new policies Programming Software Defined Radios: Now and Future “Classical” way: VERILOG Problem: hardware (board) specific, rewrite for different boards

  29. SDR with Ontology Language SDR to Operator: I’ve been an AM radio all my life, I want to become an FM radio! Operator: You’ll need to reconfigure your demodulator. SDR: How do I do that? Operator: You need 15 multipliers and 20 adders, do you have that? SDR: Yes. Operator: Now connect….

  30. About us: SDR at the Wireless Communications Lab Now: 2 Laptops running the GNU radio software, modified to work as 4 by 4 MIMO system, progam PHY In January: upgrade to 3 boards that feature VIRTEX 4 + ARM 9 + DSP, running real-time OS, program PHY, MAC and Network layers

  31. Why all that? WE WANT YOU FOR SOFTWARE DEFINED RADIO

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