Study for using Smart Radio Technologies in RF based Animal Tracking Systems
Teemu Kangasharju*
* Oulu University of Applied Sciences, School of Engineering, Oulu, Finland
[email protected]
Abstract
ISM band Radio Frequency (RF) based radio is
useful method for an object tracking when Mobile
phone network has not a range. This paper describes
shortly the study for using smart radio technologies
in RF tracking systems. In that case the tracking
means livestock, hound dog or human locating. The
study presents some aspects how to approach a
formulation of the problem. The paper describes
architectures of software defined radio (SDR). One
of the targets of study is to show that how software
defined radio (SDR) could be a good choice in
embedded tracking device.
Keywords: smart antenna, software defined radio,
cognitive radio, WNS (wireless sensor network),
tracking system, mobile phone network
1
Introduction
Nowadays wireless technology is coming to our
daily life more and more. Many of RF based location
system have a traditional hardware based radio devices
which limit cross-functionality and can only be
modified through physical intervention. This causes in
higher production costs and minimal flexibility in
supporting multiple waveform standards. The radio
transmitters and receivers have to get the best sensibility
as possible in changing conditions as from bushy forest
to open field, facing altitude changes etc. Applications
can be like to locate death animals, locate the hound dog
and for example the people tracking. In the defence
industry the tactical communications, electronic warfare
and signals intelligence solutions are based on SDR
systems.
The cognitive SDR can be one solution for these
challenges. SDR based solution can be a link to the
other radio band, because frequency band is not fixed
just for one. In the Cognitive SDR the cognitive Engine
tells the radio how to control the knobs and meters.
Basically, the cognitive radio learns from experience to
control the parameters of radio engine. This study is
focused to ISM band SDR solution. Main focus of the
study is to present the SDR and CR functionalities.
This paper describes main principles of SDR and
cognitive SDRs. Also overviews of SDR engine
architectures will be shown in this paper. One aim of the
study is to present the solution regarding with ISM band
SDR. The study looking for the solutions are already
done to integrate the workable software defined radio
system. The Result and Discussion section goes through
the results of the study. Discussion part kicks around the
possibilities with positioning application on SDR.
2
Benefits of Software Defined Radios
Simply put Software Defined Radio is defined as:
"Radio in which some or all of the physical layer
functions are software defined". The flexibility provided
by the software allows a radio to interoperate with other
devices using different wireless physical layer
technologies, by simply using the appropriate software.
The transmitters can be fitted into wireless sensor
network using 3g mobile based receiver as gateway to
the internet. This enables to control devices and change
their functional parameters remotely.
SDR defines a collection of hardware and software
technologies where some or all of the radio’s operating
functions are implemented through modifiable software
or firmware operating on programmable processing
technologies. These devices include field programmable
gate arrays (FPGA), digital signal processors (DSP)
programmable System on Chip (SoC) or other
application specific programmable processors. The use
of these technologies allows new wireless features and
capabilities to be added to existing radio systems
without requiring new hardware [1].
3
SDR and Cognitive SDR
3.1
SDR
A software-defined
radio system,
or SDR,
is
a radio communication system where components that
have been typically implemented in hardware
(e.g. mixers, filters,
amplifiers, modulators/
demodulators, detectors, etc.) are instead implemented
by means of software on a personal computer or
embedded computing devices While the concept of
SDR is not new, the rapidly evolving capabilities of
digital electronics render practical many processes
which used to be only theoretically possible [2].
Figure 1. SDR Architecture
3.2
Cognitive Radio (CR)
There are two major subsystems in a cognitive radio;
a cognitive unit that makes decisions based on various
inputs and a flexible SDR unit whose operating software
provides a range of possible operating modes. A
separate spectrum sensing subsystem is also often
included in the architectural a cognitive radio to
measure the signal environment to determine the
presence of other services or users. It is important to
note that these subsystems do not necessarily define a
single piece of equipment, but may instead incorporate
components that are spread across an entire network. As
a result, cognitive radio is often referred to as a
cognitive radio system or a cognitive network.
Figure 2. Architecture of CR engine
The cognitive unit is further separated into two parts
as shown in the block diagram below. The first labelled
the “cognitive engine” tries to find a solution or
optimize a performance goal based on inputs received
defining the radio’s current internal state and operating
environment. The second engine is the “policy engine”
and is used to ensure that the solution provided by the
“cognitive engine” is in compliance with regulatory
rules and other policies external to the radio.
4
ISM Band SDR
4.1
ISM Band Radio
The industrial, scientific and medical (ISM) radio
bands are radio bands (portions of the radio spectrum)
reserved internationally for the use of radio
frequency (RF) energy for industrial, scientific and
medical purposes other than communications. Examples
of applications in these bands include radio-frequency
process
heating, microwave
ovens,
and
medical diathermy machines.
Despite the intent of the original allocation, in recent
years the fastest-growing uses of these bands have been
for
short-range,
low
power
communications
systems. Cordless
phones,
Bluetooth devices, NFC devices, and wireless computer
networks all use the ISM bands.
Individual countries' use of the bands designated in
these sections may differ due to variations in national
radio regulations. Because communication devices
using the ISM bands must tolerate any interference from
ISM equipment, unlicensed operations are typically
permitted to use these bands, since unlicensed operation
typically needs to be tolerant of interference from other
devices anyway [6].
4.2
ISM Band SDR solutions
GNU radio is one solution for software defined radio
system. GNU Radio is a free & open-source software
development toolkit that provides signal processing
blocks to implement software radios. It can be used with
readily-available low-cost external RF hardware to
create software-defined radios, or without hardware in a
simulation-like environment. It is widely used in
hobbyist, academic and commercial environments to
support both wireless communications research and
real-world radio systems.
GNU Radio applications are primarily written using
the Python programming language, while the supplied
performance-critical signal processing path is
implemented in C++ using processor floating-point
extensions, where available. Thus, the developer is able
to implement real-time, high-throughput radio systems
in a simple-to-use, rapid-application-development
environment. While not primarily a simulation tool,
GNU Radio does support development of signal
processing algorithms using pre-recorded or generated
data, avoiding the need for actual RF hardware.
GNU Radio is licensed under the GNU General
Public License (GPL) version 3. All of the code is
copyright of the Free Software Foundation.
interfaces can be connected internally via PCI bus or
externally via USB.
The USRP series by Ettus:
During the development of GNU Radio it turned out
that no Open Source high speed interface was available.
Ettus Research took to challenge to develop the
Universal Software Radio Peripheral. The family of
hardware grew, now including different motherboards
with USB or Gigabit Ethernet interfaces, possible
sampling rates up to 100 MSPS, a range of front-ends
for reception and transmission from 0Hz up to over
5.8GHz, as PC bound device or as standalone embedded
device.
Figure 3. GNU Radio assembly
Hardware for GNU radio:
Hardware is strictly not part of GNU Radio, which is
purely a software library. However, developing radio
and signal processing code is even more fun when using
hardware to actually transmit and receive, and GNU
Radio supports several radio front-ends.
The most commonly used equipments are the USRP
devices by Ettus Research, LLC.
GNU Radio can be used on its own without any
hardware. GNU Radio has several blocks that can
generate data or read/write from/to in different formats,
like binary complex values or WAV-files. A lot of prerecorded examples exist that can be used to develop
applications without need for expensive hardware. Also,
you can ask on the mailing list if anyone has some data
available if it's a common waveform.
5
ISM band based SDR solutions can be found. Most
of SDR innovations have been done for
cellular infrastructure. There are also thousands of
software defined radios have been successfully
deployed in defence applications.
In addition, the Wireless Innovation Forum’s market
and technology studies have shown that cost effective
radio frequency technologies supporting the operation
of software defined radios over a broad spectral range
have begun to mature.
For tracking purpose SDR based system suits well.
When conditions are changed a possibility to control
radio receiver gives more dynamics to application
efficiency.
SDR Enables:

If you need to gather live real-world signals or output
signals, several different possibilities exist:





Sound interface - cheap and easy
USRP - Opensource spinoff with RF frontends
Comedi - high quality framework for
professional Data Acquisition and Output
hardware
Perseus
Sound interface:
Most computers nowadays are shipped with a built-in
sound interface or sound card. 16 Bit resolution at 44.1
kHz (kSPS) and two channels is a long available level
that you can expect. Virtually every operating system
supports this hardware out of the box, and it's sufficient
for a lot of DIY and hobby applications. You can expect
stereo (2 channels) input and output.
If the quality of a built in sound interfaces are not
very expensively built and introduce noise or show bad
frequency characteristics or degraded resolution, that is
dynamic range. Fortunately, high quality sound
interfaces are offered, like professional digital recording
equipment, with more than a dozen channels, up to
24bit resolution and 192kHz sampling rate. These
Results and Discussion

New features and capabilities to be added to
existing infrastructure without requiring major
new capital expenditures, allowing service
providers to quasi-future proof their networks.
The use of a common radio platform for
multiple markets, significantly reducing
logistical support and operating expenditures.
Remote software downloads, through which
capacity can be increased, capability upgrades
can be activated and new revenue generating
features can be inserted.
GNU Radio is a free & open-source software
development toolkit that provides signal processing
blocks to implement software radios. It can be used with
readily-available low-cost external RF hardware to
create software-defined radios, or without hardware in a
simulation-like environment. Hardware is not included
in GNU radio but GNU Radio supports several radio
front-ends.
6
Conclusions
Using programmable technologies as FPGA, DSP, or
SoC solution it allows new wireless features and
capabilities to be added to existing radio systems
without requiring new hardware.
From software aspect the solution can be found for
smart radios. GNU radio is one solution. GNU Radio
supports several radio front-ends. GNU Radio is a free
& open-source software development toolkit that
provides signal processing blocks to implement
software radios.
References
[1]
http://www.wirelessinnovation.org/Int
roduction_to_SDR
[2]
http://en.wikipedia.org/wiki/Software
-defined_radio
[3]
http://www.wirelessinnovation.org/ass
ets/documents/SoftwareDefinedRadio.pd
f
[4]
http://www.wirelessinnovation.org/Cog
nitive_Radio_Architecture
[5]
http://www.sdrforum.org/pages/documen
tLibrary/documents/SDRF-06-R-0011V1_0_0.pdf
[6]
http://en.wikipedia.org/wiki/ISM_band
[7]
http://gnuradio.org/redmine/projects/
gnuradio/wiki
[8]
http://gnuradio.org/redmine/projects/
gnuradio/wiki/Hardware