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 / JK2
© 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
© 2011 Nokia Spectrum crunch.ppt / 2011-03-31 / JK4
Real data on traffic increase
Source: CEPT PT1
© 2011 Nokia Spectrum crunch.ppt / 2011-03-31 / JK
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
© 2011 Nokia Spectrum crunch.ppt / 2011-03-31 / JK
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
© 2011 Nokia Spectrum crunch.ppt / 2011-03-31 / JK
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
© 2011 Nokia Spectrum crunch.ppt / 2011-03-31 / JK
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
© 2011 Nokia Spectrum crunch.ppt / 2011-03-31 / JK10
Essential challenges outside traditional radio technology!
Determining free spectrum
© 2011 Nokia Spectrum crunch.ppt / 2011-03-31 / JK11
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
© 2011 Nokia Spectrum crunch.ppt / 2011-03-31 / JK13
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
© 2011 Nokia Spectrum crunch.ppt / 2011-03-31 / JK
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
© 2011 Nokia Spectrum crunch.ppt / 2011-03-31 / JK
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
© 2011 Nokia Spectrum crunch.ppt / 2011-03-31 / JK16
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.
© 2011 Nokia Spectrum crunch.ppt / 2011-03-31 / JK17
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?
© 2011 Nokia Spectrum crunch.ppt / 2011-03-31 / JK18
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
© 2011 Nokia Spectrum crunch.ppt / 2011-03-31 / JK19
Coexistence in cognitive connectivity space
© 2011 Nokia Spectrum crunch.ppt / 2011-03-31 / JK20
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
© 2011 Nokia Spectrum crunch.ppt / 2011-03-31 / JK21
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
© 2011 Nokia Spectrum crunch.ppt / 2011-03-31 / JK22