Software Radio Course

A!

“Software Radio” course

Special session SNhANCE Study Tour

Kalle Ruttik

Department of Communications and Networking School of Electrical Engineering

Aalto University

A! Content

Course information Background, target group … Course structure Content of the course

Gnu radio platform Research projects around the used platform Demo

A! History of the course

”Software radio” is a new laboratory works based course that is introduced in fall 2013

Current bachelor level laboratory works are build for

illustrating and validating the communication theory It repeats the content of “theory” courses

New laboratory works course

Strengthen students software skills Build a bridge between communication theory and

programming Show how to apply theory in practice

A!

Basic courses (70 op) Aalto-studies + obligatory (10 op)

Program defines(60 op)

Major (60 op)

Program main course

Degree program subject related courses

Bachelor degree (10 op)

Minor (25 op)

Elective (25 op)

Bachelor degree

• Basic studies (70 op) - Aalto-courses + obligatory courses - Courses definded by the program

• Major (60 op) - Basic courses of the program - Bachelor thesis (10 op)

• Minor (25 op) - Minor subject courses offered by

schools of Aalto.

• Elective courses (25 op) - Additonal course in major and

minor subject - Strengthening minor (mobility) - Short minor

4

A! Information theory (IT), major 60 cr

Elective studies, Special courses (25 cr)

Select 5 courses: • Applied signal processing 5 cr (SA) • Random processes in

telecommunications 5 cr (SA) • Basics of Internet technology 5 cr

(TLV) • Application programming 5 cr (TLV) • Transmission methods 5 cr (TLV) • Software radio (Ohjelmistoradio) 5 cr

(TLV)

• Bachelor thesis and seminar 10 op

• Basics of information theory,

5 cr (TLV+SA) • Basics of automatics and

system analysis, 5 cr (AS)

• Information theory, 5cr (TLV) • Digital signal processing and

filtering, 5 cr (SA) • Modeling and analysis of

communication networks, 5 cr (TLV)

• Elective studies 25 op

A! Elective courses 25 CR

•Basics of information theory, 5 cr (TLV) •Information theory, 5cr (TLV) •Digital signal processing and filtering, 5 cr (SA) •Modeling and analysis of communication networks, 5 cr (TLV) •Signals and systems (TLV) 5 cr •Applied signal processing 5 cr (SA) •Random processes in telecommunication 5 cr (SA) •Basics of Internet technology 5 cr (TLV) •Application programming 5 cr (TLV) •Transmission methods 5 cr (TLV) •Software radio (Ohjelmistoradio) 5 cr (TLV)

Information theory (IT), minor 25 cr

A! Background information

The course belongs into bachelor degree program of Communication engineering

Course combines theory and experiments About 50 -60 students per year Prerequisites

“Signals and Systems” “Transmission methods”

The laboratory works also explores and explains system level issues not treated in any other bachelor level course in our curriculum.

A!

The structure of the course

A! Educational aspects of laboratory works

Learning outcomes specific to Laboratory works experimental skills real world experience experience for constructing actual systems discovering the results predicted by the theory familiarization with equipments motivation due to the clear practical results teamwork networking with outsides, searching information from different sources and contacts communication skills.

Broader educational targets investigation of a phenomena practicing problem solving skills practicing inquiring about the phenomenas.

A! Observed problems with laboratory works

Course organization related problems Students have different studying styles,

strict instructions vs “playing around” with equipments

Course assessment related problems Students drive to get “right answers” Too much freedom does not lead to good learning

Need of feedback from “authority”

Practical experiments implementation related issues The course too extensive, too much time spend on practical

measurements The equipments are not reliable Student groups may malfunction

A! Challenges

Mismatch between the teacher intention and students perception of the experimental work targets Students just measure and do not understand what is going on

Provide experiments with open ended questions Students tend to follow only the measurement instructions

Use wider set of assessment methods Not only assessments on measurement reports

A! Guidelines

Plan inquiry type laboratory exercises Balance between the type of experiments

Open ended questions Strict instructed measurements

Balance between the work in small groups and larger class based events

A! Structure of a lab work

Preliminary exercises Student learn the background material

First class Students plan the measurements

Laboratory measurements Done in two person teams Measurements can be done during certain days, no strict time

limits

Follow up class Analysis of the experiment results What was done, what can be concluded

A! Teaching objectives

Transceiver related topic After this course, you know how a radio transceiver is constructed.

You understand how the practical receiver differs from the theoretical models. You know how to model a non-ideal transceiver and how to measure the errors produced by the non-ideal behavior of the transceiver.

Software project You understand the structure of a software project and you are

able to participate in a large software project with multiple programmers. You know the basics of problem solving methods and you are able to apply those methods in your own projects.

Communication systems related issues You understand what the interference is. You can predict how the

interference impacts radio links and radio communication systems in general.

A! Core content Complementary knowledge

Specific knowledge

Scientific skills

Measurements: planning, implementation and analyze.

Modeling of radio systems.

Modeling and analyzing of errors

Interference concept and modeling.

Problem solving strategies.

Impact of radio environment and transceiver implementation errors on a design of a radio system.

Professional skills

Programming of radio transceivers.

Software management with version control systems.

Testing of software radios

Knowledge about measurement equipments use in testing of radio systems.

How large are the errors in existing systems.

A! Course structure

The course contains four laboratory works and an independent project. The laboratory works use software radios that are implanted by using the universal software radio platform (USRP) and GNU-radio framework.

During the course, the students study the performance of the software radio transceiver. They learn how the radio performance is described and how it is measured.

By using GNU-radio as an example, students learn how to structure a software project, how to handle version control and how to create and add new functions to the software based transceiver chain.

A! Topics of the lab exercises

Study of a transceiver chain Visualizing the theory taught on previous theory courses

Tranceiver performance measurements Learning about non-ideal behavior of the

Radio communication system measurements Interference and its impact

Software project management Cooperation with other programmers and software version

control

Learning problem solving methods Problem solving strategies and their use in small personal

project

A! Assessment method

Assessment based on the reports per group 2 person groups

Preliminary exercises: 30 points Measurement plans: 20 points Measurement reports: 50 point

A! Students workload

Laboratory work Load Introduction to a transceiver chain 25 h Transceiver performance measurements 25 h Interference in a radio environment 25 h Implementing a function for a software radio 25 h Independent project 33,5 h

One labwork Load Preliminary exercises 10 h Contact teaching 2 h Measurements 3 h Measurements reports 10 h

A! Workload

Lectures/contact hrs 0 h Exercise/contact hrs 0 h Laboratory works hrs 40 h Independent study 90 h Examination 0 h

A! Teachers workload

In a week Total Teacher 24 h 108 h Assistent 21 h 84 h

Teacher Preliminary reports: 1x20 min total 30x20 10 h Measurement reports: 1x20 min total 30x20 10 h Lectures: 4x2 = 8 h

Preparation for a lectures 4x2 = 8h Independet project: 2+4 h seminar time

Assistant Prearation for labworks: 4x3 = 12 h Measurements: 4 x 18 = 72 h

A! Content of individual labworks

How the ”analog” equations are implemented in digital computers

Each laboratory work contains

Communication theory Software radio implementation related issues Software radio development process

A! Topics of the lab exercises

Study of a transceiver chain Visualizing the theory taught on previous theory courses

Transceiver performance measurements Learning about non-ideal behavior of the

Radio communication system measurements Interference and its impact

Software project management Cooperation with other programmers and software version

control

Learning problem solving methods Problem solving strategies and their use in small personal

project

A! Lab1: Transceiver chain

Communication theory 3dB bandwidth, signal power measurements, SNR estimation FM modulation OFDM transmission Students plan: AM and FM signal SNR measurements

Software radio implementation Students will look and comment on implementation of software

radio blocks

Code development process Read and comment on GNU radio development process http://gnuradio.org/redmine/projects/gnuradio/wiki/TutorialsCor

eConcepts

A! Transceiver performance measurements

Communication theory Signal constellation and Error Vector magnitude (EVM) SINR estimation by using EVM, SNR estimation from signal

power. BER measurements Student planned measurements: Transmitter linearity

estimation and measurements

Software radio: adding and compiling a new block Gr-modtool: Students compile their own block

Doxygen Using doxygen for documenting the code

A! Radio communication system measurements

Communication theory

Interference: co-channel, adjacent channel Channel coding gain Students planned measurements: Pathloss and attenuation in

the radio channel

Software radio Students add functionality to a ready software radio block.

Noise generation block: adds noise to the input signal

Code development process Coding style quide

http://gnuradio.org/redmine/projects/gnuradio/wiki/Coding_guide_impl

A! Software project management

Communication theory Generation and using of CRC

Software radio Test driven programming

Code development process Using git version control system for managing the code

A! Learning problem solving methods

Individual project where the students have to use the learned skills

Review of problem solving strategies Students have to document their problem solving process and

describe each step in the light of the problem solving strategies

Platform

A! Transceiver

Tx software Running PC

USRP

Rx software Running in PC

USRP

Air interface Transmitter Receiver

A! Our System

Software

A! Software with USRP

Support software NI Labview

http://www.ni.com/usrp/

MathWorks http://www.mathworks.se/hardware-support/usrp.html

GNU radio

A! GNU radio

GNU radio is an open source software development kit

Hierarchical structure High level blocks in

Python Signal processing in C++

Primary a simulation tool.

A! Gnu radio

Software radio http://en.wikipedia.org/wiki/Software_radio

Core concept of GNUradio http://gnuradio.org/redmine/projects/gnuradio/wiki/TutorialsCoreConcepts

Beginners guide http://gnuradio.org/redmine/projects/gnuradio/wiki/HowToUse

Tutorial of how to write a new block http://gnuradio.org/redmine/projects/gnuradio/wiki/OutOfTreeModules

A! Under active development

Academic papers from GNU radio webpage

http://gnuradio.org/redmine/projects/gnuradio/wiki/AcademicPapers

Hardware USRP

A! Hardware

A! USRP

A! RF daughterboards

xcvr2450 2.4-2.5 GHz and 4.9-5.9

GHz Half Duplex Only

TX output power 100 mW

Single synthesizer shared between Rx and Tx

RSSI measurement that can be read from software

SBX 400 MHz to 4.4 GHz TX output power

16 to 20 dBm, with 32dB of power

control range Dual synthesizers for

independent Tx and Rx NF

< 3GHz: 5-7 dB 3 – 4 GHz: 7 -10 dB 4 – 4.4 GHz: 10 – 13 dB

A! Devices linearity

0 0.2 0.4 0.6 0.8 1-80

-60

-40

-20

0

20

Input level

Mea

sure

d O

utpu

t Pow

er [d

Bm

]

USRP2N200

Ouputim3

0 0.2 0.4 0.6 0.8 1-80

-60

-40

-20

0

20

Input level

Mea

sure

d O

utpu

t Pow

er [d

Bm

]

USRP2N200

Ouputim3

A! Linearity II input 0.1

USRP2 N200

A! USRP related research

Radio transmission in TV white/black space Y. Beyene “TV Black-space Spectrum Access for Wireless Local Area

and Cellular Networks”, master thesis, Aalto. Performance study of overlay transmission on TV signal Y. Beyenne, K. Ruttik, R. Jäntti, “Effect of Secondary transmission on

Primary Pilot Carriers in Overlay Cognitive Radios”, submitted to CrowCom 2013.

H. Tewodros, “Testing a Simple Algorithm for LTE Synchronization and Cell Search”, master thesis, Aalto. Study of the impact of delay on overlay transmission

• Synchronization schemes for cognitive BS K.G. Vishnu, “Network Time Synchronization in Time Division - LTE

systems”, diploma thesis Feb.2013. • Implementation of the time synchronization in TDD network

• MIMO transmission in USRP platform G.C. Moreno, “Communication over USRP by using multiple antennas”

Thanks