final report of project a low

LoCom group

Final Report

locomgroup.wordpress.com

iwinc.ece.uprm.edu

Final Report of Project:

A Low-Complexity Cognitive Radio

using COTS equipment

Author:

Jan Salomón, Gilberto Blas, Héctor Tosado,

Radamés Peña, Oscar García

Advisor:

Lizdabel Morales, PhD.

University of Puerto Rico, Mayagüez

Campus

ECE - Electrical and Computing Engineering

Department.

IWINC - Intelligent Wireless Networking

Communications Laboratory

May 18, 2011

Table of Contents

1. Introduction 4

2. Theoretical Frame 5

3. GNURadio Installation 10

4. Outcomes: The OFDM communication Demo 13

5. Conference and Meetings 16

6. LoCom Blog 18

7. LoCom Outreach and Workshop participation 19

8. Future Works 20

9. Bibliography 21

Introduction

This report, far from being a more detailed summary of activities that have

been realized by LoCom, shows the structure of our group and the problems

that we have encountered in the execution of the project between January and

June 2011. We will start by mentioning the state of the project at the

beginning of the semester, its evolution in those months, a comparison

between our project and those worked on by our fellow colleagues in the

Electrical and Computer Department (ECE) and finally our future works for

next semester.

To enter into context, in this work we can envision how is the current

panorama, both regionally and worldwide, in aspects relating wireless

communication, software radio and cognitive radio. Accordingly, they teach

what are our motivations, expectations and goals in the future.

Among the activities mentioned in the report we can find the literature review

of the fundamental theoretical concepts in the area of digital signal

processing, communications, software defined radio, cognitive radio and

programming languages. Similarly, the experiments that were done in the

laboratory, first to prove the functionality of the USRP and GNU Radio, and

then to test common theoretical aspects of software defined radio. Also

mentioned in the report are the meeting and conferences that we have

attended where we have reported and shared our results with fellow peers

and the engineering community in general.

Theoretical Frame

Currently, society has a big demand in its communication processes for:

connectivity, mobility, performance and throughput. We live in a world of high

demand for faster and more efficient connectivity; we wish to be able to

access theses recourses anywhere and on the fly, having slow output might

mean significant losses to a company or poor efficiency could end up costing

the company more resources than what they need to and could limit their

potential. Wireless communication devices have demonstrated to meet the

aforementioned demands with certain outcomes leaving a lot of room for

improvement. Within them, different prototypes of radios are still being

developed to reach these specific goals. According to present and future

demands in communication, Cognitive Radio (CR) is one of the solutions

considered that can address most of the problems being encountered in

wireless communications in a more cost efficient way than what is being used.

Next, we will define the most important concepts in our research:

• Software Defined Radio:

Software Defined Radio (SDR) is a radio communication system where

components that have been typically implemented in hardware are instead

implemented by means of software on a personal computer or embedded

computing devices. Software radio is the technique of getting code as close to

the antenna as possible. The fundamental characteristic of software radio is

that software defines the transmitted waveforms, and software demodulates

the received waveforms. It turns radio hardware problems into software

problems giving more flexibility with one piece of hardware.

• GNU Radio:

The GNU Radio project is an open source toolbox to develop code and deploy

software radios. There are three ways to access the resources of the GNU

Radio: GNU Radio Companion (GRC), C++ and Python. C++ is used in

applications with signal processing that are closer to the physical layer. On the

other hand, Python is used to display relevant information to the end user

through an API. GRC is a development tool bundled with GNU Radio; it utilizes

block libraries to build SDR systems. Many blocks are bundled and ready for

use, even though, the programmer can build his own blocks. All blocks are

built on C++ functions and the signal processing outcomes are displayed with

Python to the end user.

Figure 1. Structure of GNURadio

• Universal Software Radio Peripheral

The Universal Software Radio Peripheral (USRP) is a very flexible USB

device that connects a personal computer to the RF world.

consists of a small motherboard co

sample/sec analog-to-digital

digital-to-analog converters, a million gate

(FPGA) and a programmable USB 2.0 controller, 4 extension sockets (2 TX,

2 RX) in order to connect 2

through 4 Basic TX/Basic RX daughterboards (16 pins each). The USRP

daughterboard features an ISM band filter that suppresses the RF signal

outside the 2402-2480 MHz band and attenuates it withi

one dB or two. The flexibility of the USRP comes from the two

programmable components on the board and their interaction with the

host-side library.

Figure 2. Parts of

Figure 1. Structure of GNURadio

Universal Software Radio Peripheral:


device that connects a personal computer to the RF world. The USRP

consists of a small motherboard containing up to four 12

digital-converters, four 14-bit, 128M sample/sec

analog converters, a million gate-field programmable gate array


n order to connect 2-4 daughterboards, 64 GPIO pins available



2480 MHz band and attenuates it within such band by



Figure 2. Parts of LoCom’s USRP


The USRP

-bit 64M

bit, 128M sample/sec

field programmable gate array


4 daughterboards, 64 GPIO pins available



n such band by



• Cognitive Radio:

Cognitive Radio is a hybrid technology that involves the use of a software

defined radio with a host personal computer. An SDR is an important device in

our design because of the reconfigurability it offers. On the other hand, a

computer is capable of executing functions of artificial intelligence. When both

come together, it is said that we now have a CR system. One of the important

qualities of the CR is that it has the capacity of selecting the best option

between the available channels to insure a better communication. In this way

the usage of the electromagnetic spectrum will be improved. The key concept

is that CR has the ability of responding to the changes in its environment and

adapts its system’s parameters. Possible functions of cognitive radio include

the ability of a transceiver to determine its geographic location, identify and

authorize its user, encrypt or decrypt signals, sense neighboring wireless

devices in operation, and adjust output power and modulation characteristics.

• Why use ISM Band in 2.4 GHz?

The 2.4Ghz is used for two main reasons: because this band does not require

a license to tamper with (free to use) and because the USRP device operates

on the 2.4-2.8Ghz range (the former is actually the reason for the latter). What

this number means is that the USRP will broadcast at a frequency that is

within the legal boundaries of civilian use. A glance at FCC regulations

confirms that the band of frequencies around 2.4 GHz has been assigned,

along with a handful of others, as the industrial, scientific, and medical radio

bands.

Figure 3. ISM Band Frequency Spectrum

One of our main projects with the USRP will be creating a spectrum analyzer

for Bluetooth devices which also happen to operate around the 2.4Ghz range.

Since the USRP is well equipped to operate around this band, the spectrum

analyzer will attempt to detect any Bluetooth (or any commercial device, as a

later project) operating around this frequency. Creating a spectrum analyzer

out of a cheap commercial programmable radio can potentially save

thousands of dollars for people who wish to purchase a analog spectrum

analyzer which price is well over $5000 in most cases. We cannot, however,

detect anything below this frequency such as AM and FM radio or

police/military radios since the USRP does not operate within this range.

However, having a spectrum analyzer to detect commercial devices does have

its applications such as troubleshooting devices, or ensuring that any

transmitter working within this range can be detected.

Figure 4. Traditional Spectrum Analyzer

In short, the 2.4-2.8Ghz range will be ideal for testing and analyzing the

spectrum of commercial devices. The development of a cheap spectrum

analyzer will potentially allow access of a spectrum analyzer to those with a

small budget or those interested in saving money for a analog spectrum

analyzer working in the 2.4-2.8Ghz range.

• Bluetooth Sensing

Currently, the FCC is currently concerned with traditional licensed-based

policies and trying to move toward the adoption of “spectrum sharing”

strategies like ultra-wideband (UWB) and cognitive radio. While UWB systems

help achieve a more efficient spectrum usage by overlaying existing

narrowband systems, cognitive radios find and use the empty frequency

bands. Cognitive radios rely on the fact that a significant portion of the

spectrum allocated to licensed services shows little usage over time.

So where does Bluetooth come in and how is this related to cognitive radio?

Bluetooth is a proprietary open wireless technology standard for exchanging

data over short distances (using short wavelength radio transmissions) from

fixed and mobile devices, creating personal area networks (PANs) with high

levels of security and operates within the license-free ISM band at 2.402-

2.480 GHz.

Figure 5. A Bluetooth Peripheral

Since Bluetooth is a relatively new and recent technology that is available

from phones to any kind of residential, commercial or scientifical peripheral

means that one day there might be enough Bluetooth devices at any given

place that there might be interference among the devices in the same

frequency band. Cognitive radio could attempt to solve this by detecting free

space within its portion of the ISM band to ensure complete and uninterrupted

communication. This means not only that interference would be reduced, but

faster more reliable communication is ensured between devices.

GNURadio Installation

To install GNURadio in any operating system result in a big effort for any

people. After many tries, nights and endless reads, we have a guide to install

GNURadio from scratch and straight-forward on Ubuntu. The installations were

probed on Ubuntu 9.10, 10.04 and the release Maverick 10.10.

• First Method - Manual Installation

This is the most complicated of the three ways, but you can install the last

release version or any version and to control in all steps of the process. To

install GNURadio step by step follow the next steps:

1) First, you need to download the latest development code. To accomplish

this, open the terminal and enter the following command:

$ git clone http://gnuradio.org/git/gnuradio.git

(This step takes a few minutes, so please, make sure to wait until the

download is complete)

2) Then, you need to open Synaptic Package Manager and add GNU Radio

sources onto it.

Go to System > Administration > Synaptic Package Manager. Then, go to

Settings > Repositories > Other Software and click Add.

Then add the following sources:

deb http://gnuradio.org/ubuntu stable main

deb-src http://gnuradio.org/ubuntu stable main

deb http://mirrors.kernel.org/ubuntu maverickmain universe

Close that window and click Reload.

3) Search for gnuradio, right click on gnuradioand click Mark for Installation.

After that, click on the apply button.

4) By this point, you are ready to test the GNU Radio. Go to Places > Home

Folder > gnuradio > gnuradio-examples > python > audio and then run

noise.py. If this works, you have installed GNU Radio correctly.

5) In order to connect a USRP (Universal Software Radio Peripheral) devices,

you need to add a 'usrp' user group. Go to your terminal and add this

lines (Be careful, you need to substitute MachineName for the real name

of your machine):

$sudo addgroup usrp$ sudo addgroup 'MachineName'usrp$ echo

'ACTION=="add", SUBSYSTEM=="usb", ATTR{idVendor}=="fffe",

ATTR{idProduct}=="0002", GROUP:="usrp", MODE:"0660"' > tmpfile

$sudo chown root.root tmpfile$ sudo mv tmpfile /etc/udev/rules.d/10-

usrp.rules

Then,

$sudo service udev restart$ sudo ldconfig

6. Restart your machine and test your connection to the USRP by running

examples codes from:

…/gnuradio-examples/python/usrp/

• Second Method – Synaptyc Package Manager or Software

Center

The methods of installation were found to work two ways: either with the

synaptic package manager or the software center for more recent versions of

Ubuntu. The synaptic and terminal method is preferred due to the fact that it

always fetches the most recent version of the GNU radio library.

The steps to follow for the synaptic package manager are divided into two

parts:

1. Change repositories in the synaptic package manager

Some repositories need to be changed in order for the installation of the GNU

Radio to work. The installation will fail unless these are changed.

2. Checkmark GNURadio from the Synaptic Manager list

This will download the GNU Radio package. It is self-installing so not much

work is required

Figure

An alternate way of installation for the less tech savvy can be completed

through the Ubuntu Software Center. The Software Center is a

program for browsing, installing and removing software on the

operating system. The GNU Radio Library can be found in the Software Center

besides it is an almost fool

beginning of the research this was not available due to the fact that previous

version of Ubuntu was used that did not have the Software Center, but it is a

viable alternative.

Figure

Since up-to-date versions of the GNU Radio library can be found through the

use of the synaptic/terminal method, it is the preferred method. This

guarantees less error during compilation and more stable programs to be

written and run. The step by step inst

at the GNU Radio Wiki.

Figure 6. Ubuntu Software Center


through the Ubuntu Software Center. The Software Center is a comp

for browsing, installing and removing software on the

operating system. The GNU Radio Library can be found in the Software Center

it is an almost fool-proof way of a successful installation. At the

ginning of the research this was not available due to the fact that previous


Figure 7. Ubuntu Software Center

date versions of the GNU Radio library can be found through the



written and run. The step by step instructions using this method can be found


computer

for browsing, installing and removing software on the Ubuntu

operating system. The GNU Radio Library can be found in the Software Center,

successful installation. At the

ginning of the research this was not available due to the fact that previous


date versions of the GNU Radio library can be found through the



ructions using this method can be found

Outcomes: The OFDM Communication Demo

The demonstration shown in the IAP event is the most relevant outcome by

LoCom. This demo consists in the transmission of a voice signal from one

USRP to another. The software was coded using GNURadio Companion. To

capture the voice was used a microphone and after the signal was sampling

for GNURadio from the Computer’s audio card. In the receptor, the voice

transmitted was listened with commons speakers. The step by step

description is shown next:

• Transmitter (Tx)

First the block Audio Source allow to

GNURadio load the audio in the audio

card sampling to 48 KHz. The signal

loaded is a float data type variable in

the range between -1 to 1. It is desired

to have a signal among 0 and 255, thus

1 is added to the signal with the Add

Const block and after multiplied for 128

with the Multiply Const block.

The next step is to modulate the audio signal with an OFDM

modulation. The input of this block must be UChar type, is for

this reason that in the before step finish up with the block

Float to UChar.

The last step is amplifying the signal with Multiply

Const before send it to the USRP to transmit it with

USRP1 Sink. To observe the output of the USRP a block

WX GUI FFT Sink is used.

Two Slider Bars allow

the transmission frequency

When the program is running appears the

Figure 8. GUI of the OF

Two Slider Bars allow changing the transmission power and

the transmission frequency through WX GUI Slider blocks.

the program is running appears the following GUI:

Figure 8. GUI of the OFDM TX

the transmission power and

blocks.

• Receiver (Rx)

In the same way, the receiver has the same blocks that the Tx or blocks with

inverse functions, because in this case we want to demodulate the RF signal

and send it to the audio card to listen it. The following GRC program

correspond to a radio frequency receiver with modulation OFDM:

Figure 9. GRC program of RX

Conferences and Meetings

This semester Low Complexity Cognitive Radio group had the opportunity to

attend various conferences and meetings. There we were able to present our

research through power point and/or poster presentations. From the

conferences accepted are the: Puerto Rico Louis Stokes Alliance for Minority

Participation (PRLSAMP), Computing Alliance for Hispanic Serving Institutes

(CAHSI) and Industrial Affiliate Program (IAP).

• PRLSAMP - PRISM

The Puerto Rico Interdisciplinary Scientific Meeting The Puerto Rico

Interdisciplinary Scientific Meeting is the annual island wide forum for

undergraduate science, technology, engineering and mathematics

(STEM) students to present their research projects Every March over

350 undergraduate and graduate STEM students majors from the

different universities in Puerto Rico present their research projects to an

audience of over 750 faculty members and peers. The event opens with

a plenary conference by a nationally recognized scientist.

This year's PRISM took place at UIA-Bayamon campus on March 12,

2011 with the opening done by Dr. Tyrone Hayes presenting in the field

of biology.

In this conference Hector Tosado had the opportunity to do our first

presentation of the semester. There he presented our approach towards

achieving a Software defined radio, the tools used and what’s our

motivation into achieving a Cognitive Radio.

• Computing Alliance of Hispanic Serving Institutions CAHSI

Annual Meeting

This conference was celebrated March 27 through the 29th at the Caribe

Hilton Hotel at San Juan, Puerto Rico. Different talks and workshops

were offered varying from the importance of minority participation and

the importance of the GRE. In this conference both Jan Salomon and

Hector Tosado participated in the poster presentation. In this poster we

already had running examples of GRC in where we had a spectrum

analyzer receiving the signal of a nearby Bluetooth device.

• Industrial Affiliate Program - IAP

This meeting was taken place at the University of Puerto Rico at

Mayaguez on April 6 and 7. This meeting brought the opportunity to

present our work to a few of the leading companies in the industry,

companies like Texas Instrument, Harris and Verizon, so that t

see our research progress. We presented them with a demo that

consisted of two USRP’s successfully communicatin

One USRP was used to receive an audio signal from a microphone input

and the other USRP was used to receive the signal wirelessly and play it

back. This was done using the

Radio.

like Texas Instrument, Harris and Verizon, so that they could


consisted of two USRP’s successfully communicating with each other.



back. This was done using the GNU Radio Companion (GRC) from

hey could


g with each other.



Companion (GRC) from GNU

LoCom Blog

Currently Low Complexity Cognitive Radio group has a blog

keep track of our events, accomplishments and

regarding our investigation.

outside can keep tabs on our progress and ask about anything they don’t

understand or comment about a specific subject.

information about our past conferences, outreach done by our professor and

students from the research group, and

2.4 GHz and OFDM type modulation.

Blog

Currently Low Complexity Cognitive Radio group has a blog up and running to

keep track of our events, accomplishments and any important information

regarding our investigation. This can work as a tool so that people from the


understand or comment about a specific subject. At the moment we have


students from the research group, and extra information about our use of the

and OFDM type modulation.

up and running to

important information

people from the


At the moment we have


extra information about our use of the

LoCom Outreach and Workshop participation

As part of the IWinC objectives LoCom had been invited to various events and

workshops to show our developments and to meet our experiences in the

disciplines of Digital Signal Processing, Communications and

Cognitive/Software Radio. Among the events are:

• Undergraduate students Orientation by area of emphasis

• High School students Orientation in CROEM

• Open House of University of Puerto Rico at Mayaguez.

• Workshop for anniversary of 100 years of University of Puerto Rico at

Mayaguez.

• Workshop of Digital Signal Processing, organized by the Sociedad de

Ingenieros Electricistas de Puerto Rico, Chapter UPR Mayaguez.

Future Works

At our purpose of build a cognitive radio, for the next semester the LoCom

group plans:

• Review more literature.

• Design and code more Software Radios (not only USRP1).

• Study and deploy one low complexity cognitive algorithm in Python

language.

• Design and implement our own GRC block.

• Transmit and receive an image.

• To design validation experiments and create a guide for education

experiments that can be incorporated into core classes.

• To create an outreach program that can motivate students in high

school and university level to study communications and DSP.

Bibliography

1. Reed J. Software Radio, A Modern Approach to Radio Engineering.

Prentice Hall, 2002.

2. http://www.ettus.com/

3. http://www.gnuradio.org

4. Ziemer R.E, Tranter W.H. Principles of Communications: Systems,

Modulation, and Noise, 5th Edition. John Wiley & Sons, Inc., 2002.

5. Pilgrim M. Dive Into Python 3. Apress, 2009.

final report of project a low

Documents

software radio

gnu radio

cognitive radio cr

final report of project

lowcomplexity cognitive

wireless communications

wireless communication

locom group final report