Linda Doyle and Keith Nolan

Centre for Telecommunications Value-Chain Research

Department of Electronic & Electrical Engineering

Trinity College, University of Dublin, Ireland

Dynamic Spectrum Assignment

With Software Defined Radio

And Cognitive Radio

regulators

•how do frequencies get assigned to different services?

•ITU / EU / National Regulators

•STRICT RULES = COMMAND & CONTROL

•each country has a regulator for taking charge of how

spectrum is allocated in that country

•the regulators m

ust also work together to agree on

international issues

efficiencies

•technical efficiency

•economic efficiency

technical efficiency

•Th

is re

fers

to th

e re

quire

men

t tha

t diff

eren

t use

rs a

nd d

iffer

ent u

ses

of ra

dio

frequ

enci

es s

houl

d no

t int

erfe

re w

ith e

ach

not i

nter

fere

with

eac

hno

t int

erfe

re w

ith e

ach

not i

nter

fere

with

eac

hot

her

othe

rot

her

othe

r. –

co–channel interference

–adjacent channel interference

–general noise

•It

also

refe

rs to

the

need

to ta

ckle

a h

ost o

f rel

ated

pro

blem

s,–

use

of fa

ulty

or n

on-s

tand

ard

equi

pmen

t–

unau

thor

ized

or i

llega

l use

of f

requ

enci

es–

spillo

ver s

igna

ls e

ffect

s fro

m n

eigh

bour

ing

juris

dict

ions

–us

e of

inap

prop

riate

leve

ls o

f pow

er–

findi

ng th

e op

timum

loca

tion

for a

nten

nae,

–

all o

f whi

ch c

an e

ffect

affe

ct th

e at

tenu

atio

n, s

ucce

ssfu

l tra

nsm

issi

on

and

rece

ptio

n of

sig

nals

, the

pro

blem

s of

cro

ss-ta

lk a

nd th

e ge

nera

l pr

oble

m o

f cha

nnel

radi

o in

terfe

renc

e.

economic efficiency

•A

wid

er re

gula

tory

issu

e be

caus

e it

invo

lves

a ju

dgm

ent

judg

men

tju

dgm

ent

judg

men

tre

gard

ing

the

allo

catio

n of

rela

tivel

y sc

arce

spe

ctru

m

amon

g al

tern

ativ

e us

es to

pro

vide

diff

eren

t, in

som

e ca

ses

com

petin

g, ty

pes

of s

ervi

ces.

•

How

is th

e re

gula

tor t

o al

loca

te s

pect

rum

? –

On

a fir

st-c

ome-

first

-ser

ved

basi

s?

–U

sing

pur

ely

adm

inis

trativ

e cr

iteria

? –

Usi

ng s

ome

form

of s

pect

rum

pric

ing,

pos

sibl

y an

auc

tion,

so

the

mar

ket w

ill in

fluen

ce th

e ch

oice

? –

Acco

rdin

g to

som

e in

tern

atio

nal s

et o

f rul

es?

–O

ther

????

?•

Reg

ulat

ors

mus

t inf

orm

Gov

ernm

ent o

n po

licy

issu

es

influences

•a national regulator cannot work on its own as stated

earlier

•International Telecommunications Union(ITU) World

Radio Conference (WRC)

•This convenes every two to three years to make

worldwide recommendations on the allocation of

spectrum for various of radio services.

use of spectrum

In th

e pa

rlanc

e of

the

Wor

ld R

adio

Con

fere

nce

(WR

C)

the

uses

of r

adio

are

typi

cally

div

ided

into

:

•1.

radi

o se

rvice

s•

2.th

e sp

ectru

m u

sed

is d

ivid

ed in

to fr

eque

ncy

band

s•

3.ad

min

istra

tions

allo

cate

frequ

ency

ban

ds to

diff

eren

t ca

tego

ries

of s

ervi

ces

•4.

ofte

n w

ith a

lice

nsin

g pr

oces

s fo

r diff

eren

t typ

es o

f tra

nsm

issio

nby

ser

vice

pro

vide

rs w

ho u

se th

e fre

quen

cies

ass

igne

dto

them

by

the

adm

inis

tratio

n.

services

•fixed services (FS)

•broadcasting services (BS)

•mobile services (MS)

•amateur services (AM)

•technical and scientific services (TSS)

•inter-satellite services (ISS)

demand

uppe

r lim

its o

f the

ITU

’sfre

quen

cy ta

bles

.�

•Pr

e-19

47 =

200

MH

z�

•19

47 =

10.

5 G

Hz

�•

1959

= 4

0 G

Hz

�•

1971

= 2

75 G

Hz

•By

the

time

of W

RC

199

7 m

ost o

f the

ban

ds b

elow

25G

Hz

mos

t of t

he b

ands

bel

ow 2

5GH

zm

ost o

f the

ban

ds b

elow

25G

Hz

mos

t of t

he b

ands

bel

ow 2

5GH

zw

ere

in

use,

and

alth

ough

the

high

er b

ands

hav

e le

ss u

tiliz

atio

n, a

dditi

onal

ap

plic

atio

ns, s

uch

as fi

xed

wire

less

, hav

e en

croa

ched

abo

ve 2

5 G

Hz.

•

A gr

owin

g in

tere

st in

spa

ce e

xplo

ratio

n an

d in

bro

adca

stin

g sa

tellit

e se

rvic

es h

ave

also

cre

ated

a d

eman

d fo

r the

hig

her e

nd o

f the

sp

ectru

m.

do we have to listen?

•Signing ITU instruments involves only limited commitment.

•It agrees to abide by the Radio Regulations (RR) of the ITU which

have been agreed by successive W

RCs.

•This means Member States must abide by spectrum allocations that

do not cause interference with the radio stations of other Member

States.

•Military uses of RF are excluded from this consideration.

•Member States will draw up their own national frequency tables which follow

closely W

RC’stables, but they have flexibility to vary spectrum allocations

according to local circumstances

•For example, WRC allocates spectrum in frequency bands that in many

cases can be shared between different services, and local allocations may

therefore vary considerably.

harm

onisation?

•Be

caus

e th

e w

orld

is d

ivid

ed in

to s

epar

ate

juris

dict

ions

and

regi

ons,

th

e is

sues

of t

echn

ical

sta

ndar

ds a

nd s

tand

ardi

zatio

n of

spe

ctru

m

allo

catio

n ar

e cr

ucia

lly im

porta

nt.

•If

the

wor

ld a

cted

as

a si

ngle

mar

ketp

lace

, it i

s co

ncei

vabl

e th

at th

e ec

onom

ic p

ricin

g of

spe

ctru

m w

ould

allo

w la

rge

com

pani

es w

ith a

gl

obal

inte

rest

to b

uy s

pect

rum

inte

rnat

iona

lly a

nd h

arm

oniz

e its

us

e.

•In

this

cas

e, fo

r exa

mpl

e, e

very

whe

re in

the

wor

ld u

sed

the

sam

e w

avel

engt

hs fo

r bro

adca

stin

g an

d fo

r cel

lula

r tel

epho

ny, a

nd th

at

cons

umer

s co

uld

use

the

sam

e te

levi

sion

set

or m

obile

pho

new

here

ver t

hey

roam

ed in

the

wor

ld.

harm

onisation?

•That is not how the world is organized.

•Governments and regulators have to decide how far they will go in

harm

onizing their allocation of spectrum with other jurisdictions and

in adopting the same standards of equipment.

•They also have to decide how far they will go in opening their

markets to foreign service providers and equipment manufacturers.

trends

•In

the

past

man

y ec

onom

ies

in a

ll re

gion

s ch

ose

to p

ursu

e th

eir o

wn

spec

trum

allo

catio

ns a

nd s

tand

ards

, som

etim

es ju

st b

ecau

se th

e de

man

d w

as im

med

iate

and

urg

ent,

som

etim

es a

s pa

rt of

a n

atio

nal

indu

stria

l pol

icy

and

stra

tegy

.

•To

day,

on

both

the

trade

fron

t, fo

r exa

mpl

e th

e W

TO, a

nd o

n th

e in

dust

rial s

tand

ards

fron

t, fo

r exa

mpl

e th

e IT

U a

nd e

ven

com

mer

cial

pr

essu

res,

the

tend

ency

is s

trong

ly to

war

ds g

loba

l har

mon

izat

ion.

ireland& 3G

Date awarded-June 2002

Award method-Beauty Contest

Frequency bands

•A License -1920-1935/2110-2125 MHz

1915-1920 MHz

•B Licenses -1935-1950/2125-2140 MHz

1900-1905 MHz & 1950-1965/2140-2155 MHz

1905-1910 MHz & 1965-1980/2155-2170 MHz

1910-1915 MHz

ireland& 3G

Spectrum per license

2 x 15 MHz of paired spectrum plus 5 MHz of unpaired

spectrum

License Duration

20 Years

Coverage obligations

•A license -53% of the national population (equivalent to

the five m

ajor cities) by the end of 2005 and with the

fulfilmentof the m

inimum 80% population requirementby

the end of 2007.

•B License -33% of the population by the end of June 2006

and 53% by the end of June 2008.

Adult population(>15yrs)-3,012,306

rigid

rules

slow

cycle

GET / BUY

LICENCE

PLAN

USE

wasted

cash?

the radio spectrum

“…there have been four core assumptions underlying spectrum policy:

1.

unregulated radio interference will lead to chaos;

2.

spectrum is scarce;

3.

government command and control of the scarce spectrum resource is

the only way chaos can be avoided; and

4.

the public interest centers

on government choosing the highest and best

use of the spectrum.

Today’s environment has strained these assumptions to the breaking point.”

-FCC Chairman, Michael Powell, 2002

the radio spectrum

“…there have been four core assumptions underlying spectrum policy:

1.

unregulated radio interference will lead to chaos;

2.

spectrum is scarce;

3.

government command and control of the scarce spectrum resource is the only

way chaos can be avoided; and

4.

the public interest centers

on government choosing the highest and best

use of the spectrum.

Today’s environment has strained these assumptions to the breaking point.”

-FCC Chairman, Michael Powell, 2002

unlicensed activity

•Licencedbands stagnate quickly, when the spectrum is awarded people are

secure and have no incentive to change.

•In the few unlicensed bands, necessity has driven groundbreaking research

into new means of multiple users coexisting in a single band without

affecting each other.

•Because the cost of entryinto the unlicensed bands is so m

uch lowerit

encourages research into technologies that operate in those bands.

•New technologies such as bluetoothand uwbhave demonstrated the

potential for multiple users to simultaneously access and exploit a given

band.

•These and other new technologies are breaking the ‘rules’associated with

interference avoidance, and regulators are starting to realise that receivers

are as important as transmitters when it comes to standards.

the radio spectrum

“…there have been four core assumptions underlying spectrum policy:

1.

unregulated radio interference will lead to chaos;

2.

spectrum is scarce;

3.

government command and control of the scarce spectrum resource is the only

way chaos can be avoided; and

4.

the public interest centerson government choosing the highest and best use

of the spectrum.

Todaysenvironment has strained these assumptions to the breaking point.”

-FCC Chairman, Michael Powell, 2002

August 31 to September 1, 30 MHz –54 M

Hz

Source: Shared Spectrum Company(http://www.sharedspectrum.com/)

spectrum usage

This is the measurement taken over a 24 hour period in central London, July

2004. The solid blue represents no activity, while red represents heavy

activity.

the radio spectrum

“…there have been four core assumptions underlying spectrum policy:

1.

unregulated radio interference will lead to chaos;

2.

spectrum is scarce;

3.

government command and control of the scarce spectrum resource is

the only way chaos can be avoided; and

4.

the public interest centers

on government choosing the highest and best

use of the spectrum.

Todaysenvironment has strained these assumptions to the breaking point.”

-FCC Chairman, Michael Powell, 2002

an alternative way…..

dynamic spectrum access

what is dynamic spectrum m

anagement?

dry / official

The process which enables the dynamic m

anagement

(allocation, de-allocation, sharing) of radio resources

(time slots, frequency carriers, codes) within a single or

between different radio access systems.

another definition

•dynamic spectrum access approaches consist of a

variety of techniques for accessing spectrum in a m

ore

flexible and dynamic m

anner.

•some techniques co-exist with current approaches

•others are completely new and would involve really new

approaches

benefits?

1.

Improved spectral efficiency

2.

Increased capacity

3.

More competitive market driven pricing mechanisms

4.

Improved ease of access to the spectrum

-Smaller parties enabled to enter the market as costs are reduced

5.

Rewards for innovation and incentives for improved efficiency

6.

Natural migration of spectrum to those users that will use it most

efficiently

time

frequency

space

t h e p r e s e n t …

.

time

frequency

space

t h e f u t u r e …

. Spectrum trading

time

frequency

space

t h e f u t u r e …

.

How?

•Software Defined Radio

•And

•Cognitive Radio

NOKIA 6163

•Quad-band GSM/EDGE coverage on up to five

continents (GSM 850/900/1800/1900)

•so deals with different frequencies and different

standards

•increasing amounts of functionality squashed into

devices

•complexity can be obtained through using m

ultiple

hardware solutions that are well integrated to give the

multiple functionality needed.

•or you can embrace software …

………….

s o f t w a r e r a d i o

work

in

digital

domain

work

in

digital

domain

•One of the first software

radios was a U.S. military

project named SpeakEasy.

•Aimed to use programmable

processing to emulate

more

than 10 existing m

ilitary

radios, operating in frequency

bandsbetween 2 and 200

MHz.

•Further goal to easily

incorporate new codingand

modulation standards in the

future, so military

communications can keep

pace with advances in coding

and m

odulation techniques.

•The typical architectural approach to SDR locates a wideband

analog-to-digital converter (ADC) very near the antenna of an RF

system in order to sample and digitize incoming RF waveform

s.

•The channel modulation scheme is therefore implemented

completely in software, so down-conversion and demodulation

happen entirely in the digital domain, typically on a digital signal

processor (DSP) or other general purpose processor.

•This setup is extremely versatile, of course, because the software

that defines the scheme can be swapped on the fly, so one

hardware platform

can implement an almost infinite variety of radio

standards without modification.

Cognitive radio

cognitive radio

•Cognitive Radio is a reconfigurable node in a wireless network with cognitive

functionality. –used software defined radio

•Cognitive functionality: awareness, decision m

aking, learning and conclusions

form

ation.

•Enhance the ability of a wireless device to establish and m

aintain the flow of

inform

ation across a wireless communications channel.

•Ability to make internal and external observations, take pre-emptive action

according to the needs of the user, make decisions autonomously,learn from

past experiences and conclusions….

•Many different and sometimes conflicting interpretations of cognitive radio

exist. This is a still a relatively new concept. Cognitive functionality can

influence the entire communications stack and not just the ‘radio’part of it.

Cognitive Engine

Reconfigurable Node

1.Radio Environment Changes(e.g. changes in communication channels

conditions, increased/decreased noise etc.)

2.Netw

ork Environment Changes(e.g. changes in the density, degree,

mobility, size, membership of the network etc.)

3.Regulatory Environment Changes(e.g. movement from US to EU, change

from liberal to non-liberal jurisdiction, etc. )

4.Communication (Application) Requirement Changes(e.g. changes in

bandwidth requirements, changes in data rates needed, changes inprocessing

power needed etc.,)

5.Physical Environment Changes(e.g. changes from day to night, rural to

urban, hot to cold, physical location, etc.)

6.Business Environment Changes(e.g. changes in tariffs, changes in

willingness to pay, changes in level of competition available, upgrades etc.)

7.Social Environment Changes(e.g. changes in social norm

s to a collaborative

environment, emergency call on resources etc.)