Software-Defined Radio - Grove City College

Software
-
Defined Radio

An Activity in LIVE
-
M Laboratory

Principle Investigator

Professor William Birmingham

Chair, Computer Science Department

Grove City College

wpbirmingham@gcc.edu

724 458 3794

Overview

Software
-
defined radio (SDR) is an important technology that underlies many modern wireless communication
s

systems. For example, most
cell
-
phone handsets
and wireless routers
are based on SDR technology.
This
technology is popular among computer scientist
s
, with several interesting software projects underway, such as the
GNU radio


and Flex
R
adio’s SDR 1000

and SDR 5000
.

Essentially,

SDR replace
s

much of the electronics in a radio with software
. By substituting many hardware
components for software, SDR prov
ides
flexibility with baseband waveforms, frequencies, and features. The
software necessary to drive an SDR includes real
-
time signal processing,
a
user interface, and other processing
tasks.
Therefore, a
n SDR is a self
-
contained
,

embedded software system with real
-
time deadlines and hardware
interfaces.

Software
-
defined radios
rely on some hardware, minimally a down
-
converter and A/D for receiving and a D/A and
an
up
-
converter for transmitting. While the hardware circuitry is well

defined, it
can be challenging to

build
because
radio
operating frequencies are, naturally enough, in the radio frequency (RF) spectrum. While cell phones
are typically in the GHz range, our applications are in the
0
.1
MHz

–

100 MHz range, specially, the
amateur
, public
service,

and commercial radio bands.

Areas of
Ongoing

Research

T
he SDR has become a popular research project

with the following applications.

SDR and

P
ublic
S
afety

In this project, we are

develop
ing

inexpensive
, Pocket

PC
-
based SDR systems
for public
-
safety applications
.

Creating these “portable” SDR
s

will

allow emergency personnel to
use

a variety of radio bands during disasters. In
addition, these radios will work on the amateur radio frequencies.

Because most communications systems other
than amateur radio go down during

disasters
, SDR could allow emergency personnel to gain the information they
need in a dependable fashion.
Additionally, there were significant communications mismatches between police,
firefighters and other emergency pers
onnel during Hurricane Katrina and the September 11
th

terrorist attacks. The
flexibility o
f SDR could help to rectify miscommunication

between different branches of public servants.

SDR and

“High
-
Definition” Radio

We are developing addition
al

plug
-
ins for

commercial radio broadcasts of digital AM and FM, commonly called
“high
-
definition” radio. These new waveforms are intended to give AM radio the quality of current FM stations and
to

broadcast

FM stations
at
the quality of CDs.

Based on the

SDR
library s
oftware, we
are
building
decoders for these waveforms. This is a pure software
project using the same down
-
converting hardware as the other SDR projects.

Mobile Gaming Platforms

Mobile gaming is an important emerging technology. Electronic Arts,
Microsoft, and Google, for example,
have made major commitments to mobility. We are interested in developing high
-
performance computing and
communication platforms specifically to support mobile gaming
, communication and computation
.

Course Opportunities

I
nterested students are encouraged to take Computer Science department courses in digital
-
signal
processing and in
SDR
. These courses provide the in
-
depth exposure to the mathematics, software, and system
concepts in SDR.

Research Opportunities

Interested s
tudents, from sophomore through senior years, are encouraged to participate in
these

exciting
project
s
. Please contact Professor Birmingham
.