Cognitive radio – the way out of spectrum crunch?

Cognitive radio – the way out of spectrum crunch?

Cambridge Wireless Radio Technology SIG

Avoiding Cellular Gridlock: finding new ways forward in radio

March 31st, 2011

Jussi Kähtävä

Director, Technology Policy

Nokia

© 2011 Nokia Spectrum crunch.ppt / 2011-03-31 / JK1

Presentation outline

• Regulatory framework on spectrum

• Ways of accessing spectrum

• Where does cognitive radio step in?

• Impacts on devices

• Spectrum access

• Coexistence

• Conclusions


© 2011 Nokia Spectrum crunch.ppt / 2011-03-31 / JK

Traffic Forecast – x100

0.0

0.5

1.0

1.5

2.0

2.5

2007 2008 2009 2010 2011 2012 2013 2014 2015

Global MOBILE traffic (ExaByte/month)

Handhelddata traffic

LaptopData Traffic

VoiceTraffic

0

20

40

60

80

100

2007 2008 2009 2010 2011 2012 2013 2014 2015

Global FIXED traffic (ExaByte/month)

ResidentialUnicast TV

ResidentialInternet

BusinessInternet

VoiceTraffic

Source: analyst reports and internal research

Fixed broadband trafficis 40x mobile in 2015

Mobile data trafficgrows 300 fold

I want only one TV channel -Mine!

Source: Lauri Oksanen,

Nokia Siemens Networks

Price per bit needs to

decrease significantly!

3


Real data on traffic increase

Source: CEPT PT1


Framework for Regulation

ITU Radio Regulations

Intergovernmental. Frequency allocation table, definitions, protection primary services

ITU Radio Regulations

Intergovernmental. Frequency allocation table, definitions, protection primary services

Regional Regulations

General authorisations

CITEL,APT,EU/CEPT, ATU

Regional Regulations

General authorisations

CITEL,APT,EU/CEPT, ATU

National regulations

Assignments

FICORA, BNetzA, OFCOM, ARCEP, AGCOM, IBPT..

National regulations

Assignments

FICORA, BNetzA, OFCOM, ARCEP, AGCOM, IBPT..

Pro

tec

tion

& In

terfe

ren

ce

5


Co-ordination of spectrum

• Need for co-ordination at global and regional level. Common frequency arrangements facilitate.

• Border coordination

• Economies of scale for equipment

• Cost effective systems

• Wider consumer & citizen choice of different device types and brands

• Interoperability roaming

• Spectral efficiency

A purely market driven approach without any co-ordination leads to fragmentation chaos & ultimately value destruction

for all including citizen consumers

6


Roadmap with spectrum

Licence-exemptLicensed

Slow process

High investments in beginning

Effective

QoS

Enduring business

model

Global

No process

Low threshold in

beginning

Tragedy of

commons

No guarantee on QoS

Enduring

business model

Mainly local

Authorised use

Flexible process

Initial investment according to market price

Effectiveness and QoS

reachable

New business models

Global contract and local flexibility

7

Authorisation options

© 2008 Nokia V1-Filename.ppt / YYYY-MM-DD / Initials8

Individual

authorisations

(= Licensed)

General

authorisations

(=license exempt

= unlicensed)

Authorised

primary

use

Authorised

secondary

use

Use under

general

authorisation

Exclusive

access

Shared

primary access

Authorised

secondary access

Horizontal shared

access

Horizontal shared

secondary access

E.g. Cellular networks,

broadcasting

E.g. WLAN,

Bluetooth

NEW

TV White

Space

E.g. operated DECT

and PHS

NEW

sharing on

licensed bands

= facilitated or enhanced

by cognitive technologies


New Spectrum Rules

• Among the first deployments, TV White

Spaces bring primary/secondary sharing

between TV broadcasters and mobile wireless services

• Analogous sharing approaches can be considered in other spectrum bands, BUT

licence-exempt is not the only approach

• Sharing can take place on the basis of both individual authorisations and general

authorisations

© 2010 Nokia 99

Individual

authorisations

General

authorisations

Vertical

Sharing

Horizontal

Sharing

Licence-exempt

Protected primary,

negotiations between parties

Negotiations between parties

Protected primary,

opportunistic secondary users

Conscious and polite radio

• Transmits and receives

• Hears and sees

• Knows its status and the

environment

• Understands needs via applications

• Discusses with other radios

• Discusses with databases

• Might cause interference

• Aims to Prevent harmful interference

• Expects politeness


Essential challenges outside traditional radio technology!

Determining free spectrum


Sensing Geolocationdatabase

Beacon channel

• Determination of available spectrum made at the device or in cooperation with a number of devices

• The maturity of sensing technology remains an issue

• Does not play a major role in current regulatory decisions

• Needed to enable truly cognitive devices

• In future, potential for knowledge on real local conditions

• Has not attracted much interest

• Determination of available spectrum done centrally

• Likely requires dedicated spectrum

• Approach of choice for TV WS

• Determination of available spectrum done centrally

• Not truly “cognitive radio” fromthe device point of view

• A robust first step in varioussharing scenarios on various spectrum bands

© 2009 Nokia WS database.ppt / 2010-01-29 / JusK12

Mandatory part

Geo-location database: general concept

Spectrum use information

Repository database

Additional information

Query DB

Synchronization ->

<- registration

Regulator

Repository database may or may not be open to end user access

Mandatory part

Query DB

Data repository

Smarter radios do not negate the need for harmonisation! • Every different spectrum

band supported adds cost to a device

• Benefits of scale as important to an agile radio than to a dumb radio

• Piecemeal approaches in individual countries will not encourage investment and market emergence


Open

competition

between

service

providers

Sufficent,

harmonised

spectrum

Favourable

regulatory

environment

Well defined

open

standards

Fair device and

service costs for end users

Impacts on device

• Detection sensitivity

• How to avoid false detection

• Cooperative sensing

• Coordination needs with other devices

• Device is optimized to a known incumbent, what happens if the incumbent transmission changes

• One can only prepare for specific

signal types, not all

• Geolocationing

• How is it determined (at

installation for fixed device, GPS,

cell ID, some network based

location scheme)?

• Geolocation accuracy

• Assumes IP access to DB


Sensing Geolocation database

14

Types of device connectivity

• Client does not access spectrum independently

• Only master device is connected to a geolocationdatabase, and makes decisions on spectrum bands to be use by clients

• Master determines its own location and possibly also the approximate location of the client devices

• Moving networks

• Mesh networks

• Adhoc device to device connectivity

• long distance point-to-point links

• No clear master-client setup, devices more independent in spectrum access


Master-client setup Other types of connectivity

15

Device impacts from connectivity

• management of

connectivity, i.e. IP

interfaces change often

• multiple interfaces active at

the same time

• seamless connectivity and

mobility impacts

• interface selection policies, flow handling


Operated networks

RAN type A RAN type B

Independent networks

Multiradio devices

Regulatory information

system

Cognitive Control

Network

How does the device adjust to the radio environment?• Transmission BW

• Transmission power

• Fixed maximum output power (FCC) or

location specific maximum output power (SE43)?

• When to vacate use frequencies and

how quickly

• Device classification should enable pre-calculation approach or

fast real time calculations in DB

• E.g. ACLR has direct relevance to

possible Tx power within a given

transmission mask and BW

• device classification should enable

flexibility in device implementation

and operation (e.g. different cost

category devices/wider bandwidths) but also promote

efficient spectrum use.


Device class

Spectrum masks

• In TV WS and cognitive radio scenarios in general, the role of spectrum mask is different

• In licensed bands today, spectrum mask is designed for harmonized standards and it is sufficient for the equipment to be designed for a specific mask

• What happens when:

• Several modulation and multiple access schemes in use in same band

• Both FDD and TDD devices present in same band

• What is the correct mask? Is it designed based on a standard deployed today?


Coexistence - Levels of Collaboration

• Wild West: Decision-makers optimize their own situation, not taking into account any interests of others

• Cooperation: Decision-makers optimize their own situation, while taking into account the interests of others

• Collaboration: Interacting decision makers to optimize their performance, this is based on active/explicit communication between the decision-makers

• Standardization ongoing in IEEE 802.19 and in ETSI RRS


Coexistence in cognitive connectivity space


Neighbour discovery

Spectrum negotiation

Cooperative spectrum sensing

Policy discovery

Time synchronisation

Negotiations of the available spectrum use between the secondary users.

Discovery of nearby networks to identify coexistence peers, or discover optimal networks for connectivity

Mechanisms to share spectrum sensing results and configuration. May include agreeing on sensing times, responsibilities and thresholds.

Mechanisms to share and access local policies. Policies may related to spectrum use, but also to node/network settings.

Common silence periods for sensing the primary user enables more reliable sensing results. Also, efficient use of available spectrum resources may require timesharing between coexisting networks.

Certification

• Who certifies the CR devices and how?

• The normal way is to have an ETSI harmonised standard, based on which vendors

make declarations of conformity

• Is that agile enough a way? Innovative technologies may face a chicken-and-egg

problem

• Who certifies the geolocation database and how?

• It is very important to have devices receive their spectrum information only from

trusted databases

• N.B. Rogue devices would hardly contact a geolocation database in the first

place. Do not make requirements too onerous for the rest of industry just to

minimize the possibilities of troublemakers


Key messages

• Everyone needs more spectrum, and it is not fully utilized

• Cognitive radio technologies can provide means of improving spectrum utilization through flexibility in access and sharing

• We won’t see “real” CR at first, things need to start with a coordinated approach (geolocation databases)

• Sharing can take place both on license-exempt and individually authorised basis

• CR is not a silver bullet for spectrum needs. Also CR devices need to be “nurtured” with harmonized spectrum, standards and feasible device requirements
