Software defined radio....

Name :- Pranab Kumar Bandyopadhyay

University roll:- 071690103020

Presentation date :-04-03-2011

SOFTWARE

DEFINED

RADIO

Discussion details

Standard radio vs. SDR Advantages Areas of application Components Ideal concept Architechture History Practical Uses

...........

a radio communication systemComponents in HARDWARE

basically ANALOG Typical

system

Components in SOFTWARE

basicallyDIGITAL

SDR

vs.

Advantages :->

can serve a wide variety of changing, widely different radio protocols in real time

digitally interfacable quickly reconfigurable architecture can be encrypted

Areas of application

Military communication Mobile phones

N.B. - which must serve a wide variety of changing radio protocols in real time

Components:-> A Personal Computer

A sound Card (or any other analog-to-digital converter)

An RF front-end(a tuner maybe)

Ideal concept

ADC DSP Amplifier

antennaspeaker

Inside Architecture1. variable-frequency oscillator, mixer, and filter

(to tune the desired signal to a common intermediate frequency or baseband)

2. analog-to-digital converter (for sampling & analog to digital conversion)

3. low-noise amplifier must precede the conversion step (Real analog-to-digital converters lack the dynamic range to pick up sub-microvolt, nanowatt-power radio signals)

4. band-pass filters between the antenna and the amplifier (If spurious signals are present (which is typical), these compete with the desired signals within the amplifier's dynamic range. They may introduce distortion in the desired signals, or may block them completely)

History•First evolved as ‘software radio’ in 1984 by a team at the Garland Texas Division of E-Systems Inc. (now Raytheon)

•Basically a digital baseband receiver; providing programmable interference cancellation & demodulation for broadband signals, (with thousands of adaptive filter taps, using multiple array processors accessing shared memory)

•origins in the defence sector since the late 1970s in both the U.S. and Europe

•"Software Defined Radio" :- coined in 1991 by Joseph Mitola

•One of the first public software radio initiatives was a U.S. military project :-> SpeakEasy

• managed by :-

The SpeakEasy

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

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

SPEAKeasy phase I a radio for the U.S. Army which could operate from 2 MHz to

2 GHz operate with :->

Ground force radios (frequency-agile VHF, FM, and SINCGARS),

Air Force radios (VHF AM) Naval Radios (VHF AM and HF SSB teleprinters) Satellites (microwave QAM)

1992 to 1995

DOWNconverter/frequency mixer

Automatic gain control

Analog to Digital

converter

Digital signal processors

(Texas instruments T40)

VMEbus

Analog to digital converter

UP converter

Power amplifier

Antenna

Transmitter

Receiver

PCI bus

INPUT

OUTPUT

demonstrated at TF-XXI Advanced Warfighting Exercise

Problems:-.• Its cryptographic processor could not change context fast

enough to keep several radio conversations on the air at once.

• Its software architecture, though practical enough, bore no resemblance to any other.

SPEAKeasy phase II

GOALS:-> more quickly reconfigurable architecture (i.e. several

conversations at once) an open software architecture, with cross-channel

connectivity (the radio can "bridge" different radio protocols)

make it smaller, cheaper, and weigh less.

Range:- 4 MHz to 400 MHz

Time line:- a demonstration radio only fifteen months into a three-year research

project

Inside A software architecture identifying standard interfaces for

different modules of the radio "radio frequency control" to manage the analog parts of the radio "modem control" for managing resources for modulation and

demodulation schemes (FM, AM, SSB, QAM, etc) "waveform processing" modules for performing the modem

functions "key processing" and "cryptographic processing“ for managing

the cryptographic functions "multimedia" module for voice processing a "human interface" to provide local or remote controls a "routing" module for network services a "control" module to keep it all straight

Advantages communicate without a central operating system send messages over the PCI computer bus to each

other with a layered protocol As a military project, the radio strongly

distinguished "red" (unsecured secret data) and "black" (cryptographically-secured data)

time to download a stored FPGA program is around 20 milliseconds(an SDR could change transmission protocols and frequencies in one fiftieth of a second, probably not an intolerable interruption for that

task)

Tactical to Practical

Joint Tactical Radio System (JTRS) Amateur software radio

Joint Tactical Radio System (JTRS) is a program of the US military to produce radios that provide flexible and interoperable communications

Example---audio terminals that require support include hand-held, vehicular, airborne and dismounted radios, as well as base-stations (fixed and maritime).

Uses the SDA based on the Software Communications Architecture

Operating Systems used: CORBA on POSIX

Amateur or home use Uses a direct conversion receiver

Mixers used are based on the quadrature sampling detector and the quadrature sampling exciter

Open source SDR library DttSP for Digital signal processing

SDR software performs all of the demodulation, filtering (both radio frequency and audio frequency), signal enhancement (equalization and binaural presentation)

Uses include every common amateur modulation: morse code, single sideband modulation, frequency modulation, amplitude modulation, and a variety of digital modes such as radioteletype, slow-scan television, and packet radio. Amateurs also experiment with new modulation methods(for instance, the DREAM open-source project decodes the COFDM technique used by Digital Radio Mondiale)

The GNU radio

Uses the Universal Software Radio Peripheral (USRP) a USB 2.0 interface an FPGA high-speed set of analog-to-digital and digital-to-analog

converters reconfigurable free software

sampling and synthesis bandwidth :- a thousand times that of PC sound cards( enables wideband operation)

a signal processing package, which is distributed under the terms of the GNU General Public License. The goal is to give ordinary software people the ability to 'hack' the electromagnetic spectrum, that is, to understand the radio spectrum and think of clever ways to use it.

The HPSDR (High Performance Software Defined Radio)

• Uses a 16-bit 135 MSPS analog-to-digital converter(range 0 to

55 MHz )

•Also operate in the VHF and UHF range using either mixer image or alias responses

•Interface to a PC by a USB 2.0 interface or Ethernet

•Components are interchangeable by use of a backplane

Thank you

•Rohde, Ulrich L. (February 26–28, 1985), "Digital HF Radio: A Sampling of Techniques", Third International Conference on HF Communication Systems and Techniques (London, England)

 •Rohde, Ulrich L. (April, 1985), "Digital HF Radio: A Sampling of Techniques", Ham Radio Magazine 

•Wireless Innovation Forum (formerly SDR Forum Website)

•SDR4all, tool for research and teaching

•Wikipedia, the free encyclopaedia (www.wikipedia.en)

Questions?