RADIO RESOURCE MANAGEMENT a necessary evolution

1
RADIO RESOURCE MANAGEMENTa necessary evolution

• REV06
• HANOI 6-7/11/2006
• Bernard FINO
• Conservatoire National des Arts et Métiers, Paris
  (France)

2
Contents

• Expansion of radio needs
• Characteristics of frequencies
• Present RRM process transmitter centric
• New proposals
• Possible evolutions
• Conclusions

3
Growing demand on cellular systems
Success of Cellular Mobile radio
(WAN) -Everybody -Data (SMS, I-Mode, Internet,
photos, music) -Simple video( Clips,
videophone, news) -Movie video, TV. .very
high bit rates will be required and so
spectrum Upcoming complementary systems
- Satellites, MAN , LAN and PAN
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Lines or radio?

.

• Historic copper lines revived with xDSL
  technology
• Power lines communications difficult to
  generalise
• Fiber optics only dense areas
• Radio offers
• Simplicity and rapidity
• Adaptability
• Lower costs
• BUT QUESTION IS SPECTRUM FOR HIGH DATA RATES

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SETS OF RADIO NETWORKS
Satellites
WAN
WAN
IEEE 802.20
3GPP, EDGE
IEEE 802.20
3GPP, EDGE
(proposed)
(GSM)
(proposed)
( GSM,UMTS)
MAN
MAN
IEEE 802.16
-
ETSI HiperMAN
IEEE 802.16
-
ETSI HiperMAN
WirelessMAN
HIPERACCESS
WirelessMAN
HIPERACCESS
(WiMax)
LAN
LAN
IEEE 802.11
-
ETSI
IEEE 802.11
-
ETSI
WirelessLAN
HiperLAN
WirelessLAN
HiperLAN
(WiFi)
PAN
PAN
IEEE 802.15
-
ETSI
IEEE 802.15
-
ETSI
Bluetooth
HiperPAN
Bluetooth
HiperPAN
UWB
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SATELLITES

• Early systems were out of phase Iridium
• Satellite Digital Multimedia Broadcasting
• Spectrum efficiency (large broadcast cells)
• Coherent with terrestrial WAN  plugable  on 3G
  networks
• Frequency reuse on satellite and on terrestrial
  repeaters
• Cost effective (5euros per terminal!)
• POTENTIAL HIGH DEMAND

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Wireless-Local Area Network WiFi family

• A serie of standards IEEE 802.11a,b, gn
• Starting from nomadic PC connection
• Growing rates.1,2,11,56, 108Mbit/s
• Mobility and security coming
• VoWAN (voice capability) coming
• with classes of services and time control
• a very high potential complementary to
  cellular networks

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Personal Area Network

• -Already success of Bluetooth for PC and HH
  devices
• -Arrival of Zigbee to market
• (lower costand rates , higher autonomy, for
  captors networks)
• -UWB best market possibility in home applications
• -Many short range devices appear.
• we can expect that most objects will be
  radioconnected soon!

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Other growing demands
May include -Mobile terrestrial TV DVB-H with
more professionnal and educational
channels -Intelligent transport systems safety
in vehicules -Home transmission and
surveillance -Mobile Very high data rates
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Home transmissions


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Home surveillance
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BEYOND 3G.4G..?
Technology evolution to higher bandwidths
provides more flexibility and benefits
Fibre
Bandwidth
Beyond 3G And 4G
802.16 WiMAX
VDSL
DVB-S2 Satellite
WLAN 802.11
ADSL, ADSL2plus
802.20
UMTS R5 R6
CDMA2000 EV-DV
Cable
DVB-S Satellite
UMTS
CDMA2000 EV-DO
Dial-up
EDGE
CDMA2000 1X
GSM/GPRS
Mobility
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WIRELESS GIGABIT with ADVANCED MULTIMEDIA WIGWAM
1 Gb/s and Mobility ?
When can we expect 1 Gb/s WLAN ?
WIGWAM
IEEE 802.11n
1Gb/s WLAN
IEEE 802.11b
Trade-off Data Rate vs. Mobility
WLAN Data Rate (Mb/s) vs time
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CERTAINTY HIGH PRESSURE ON SPECTRUM

• Spectrum will be under very high demand
• Convergence of telecommunication, audio and video
  distribution and computer networks
• At the same time military, security, scientific,
  medical..usages will also continue to grow.
• With a limited spectrum radio resource management
  is in question.

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Characteritics of frequencies(1)

• Bands should be adapted to the range
• Infinite reuse with smaller cells
• Numerous and changing propagation difficulties to
  overcome many methods aimed at using the
  necesserary power with reduced margins
• Propagation extends over States borders
  international process
• Large power excursion at reception easy
  interferences

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Characteritics of frequencies(2)

• Free natural resource but important economical
  value
• -easy money to States
• -good to be sold, rented, source of
  speculations
• -  beauty  contests or auctions
• Can we apply the offer and demand market laws?
•  Benefit for all  should be optimised is money
  a valid criteria?

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Present system of spectrum allocation(1)
Three levels -International International
Telecom Union Radio (part of UN) 192 member
states regular study groups World Radio
Conferences (next in 2007) Radio Regulations
Tables -Regional 3 ITU regions and 6 regional
groups -National only real authority for
licensing


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Present system of spectrum allocation(2)
-Allocation based on  Services  i.e. fixed,
mobile, broadcast, aeronauticaletc -Status of
primary/secondary (secondary means no
interference no protection) -Presence of
numerous  footnotes  (modifications in certain
countries) -Numerous bilateral agreements for
coordination at borders a long complex
diplomatic process not adapted to the growing
radio demands.


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Present system of spectrum allocation(3)
EUROPEAN LEVEL -ETSI stardards within spectrum
constraints -Directive RTTE (with committee
TCAM) use of spectrum -Mandate to CEPT
(regulators association) for -technical
studies - decisions  binding
administrations -Spectrum decisions prepared by
RSCOM at EC level for spectrum
harmonisation growing concern and coordination.


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Present system of spectrum allocation(4)


NATIONAL LEVEL -Independant agency for overall
coordination of frequencies and
control -Specific regulation agencies for
telecom, broadcastersetc for frequency
assignment (different allocation) -Application of
international decisionswhenever
possible -National plan for sites, frequencies,
authorised powersetc
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Limits of present system(1)

• Convergence between Radio Services for telecom,
  broadcast and information
• In contradiction with present allocation system
• Define a new Super Radio Service?
• Give flexibility to provide services and adapt
  the adequate licensing framework?

BROADCAST
FIXED and MOBILE TELECOM
INTERNET DATA
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Limits of present system(2)


1- The spectrum is completely allocated and
difficult to refarm 2- Sharing is quite
limited 3- Allocation is centered on transmitter
characteristics when the problem is at
receiver 4- Trend is liberalisation technology
independant spectrum trading which does not
help to coordinate spectrum usage RESULT
SPECTRUM SHORTAGE .WHILE LITTLE USED
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Limits of present system(3)

• Many differences in pricing
• Countries are different for identical systems
• Free to very high fees
• Access and/or use taxes
• Administrative and/or incentives
• Redistribution through refarming

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New proposals

• Common bands general licence(ISM for WiFi,
  Bluetooth..etc)
• No control on saturation.
• Ultra Wide Band
• Interference temperature
• Adaptive systems
• Multichannels
• Cognitive and reconfigurable terminals

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ULTRA WIDE BAND (1)

• Coded impulses over a very wide spectrum
• Very low interference levelbut very large
• Two technologies considered
• Multiband OFDM sculptured spectrum possible
• DS-CDMA very simple

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UWB Spectrum shape (2)


.
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UWB, DSP
UUWB
UWB (3)
t 0.3 ns
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UWB Conclusions (4)

• Transmission of a set of pulses is an old dream
  .
• ? No synthesiser,no phase noise, no frequency
  tracking
• ? No carrier, no fading
• ? Easy multiple access
• No multipath recombination
• Very low interference level

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UWB Conclusions (5)

• .Transmission of a set of pulses is a nightmare
  .?
• ? synchronisation
• ? Separation of multiusers and multipaths
• Very high pulse rate for a much lower data rate
• For RRM is it better to fill bands or to avoid
  bands?
• Seems to be dual equivalent strategies but it
  does not introduce a clean sharing mechanism.

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Interference temperature (1)

• FCC notion under discussion
• Centered on receiver and adaptative
• Transition with present system
• Still primary service but accepting a fixed level
  of interference
• Any other user can transmit if it does not induce
  a level of interference at primary users below a
  threshold
• Received power cannot exceed a threshold

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Interference temperature (2)
Received power
Level at which receiced power impacts sharing or
cochannel users
Interference t
Noise floor(K)
Distance from transmitter
Original service range
Minimum service range with interference cap
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Interference temperature (3)

• Interesting principle but how to implement?
• Detect dynamically  white areas  (and black)
• In grey areas how to organise the feedback to
  transmitters?
• Presence of a centralised monitor?
• Presence of  captors  to measure the t?
• How to pinpoint the responsible transmitters?
• What allocation optimisation?

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Multichannels

• Multiple antennas at base station and eventually
  at terminal
• opens many channels partially decorrelated
• increase in capacity and better average
  propagation
• But
• -High cost in hardware and software
• -Difficulty to adapt to propagation conditions
  and to optimise
• -Is there a global benefit with  pollution
  increase ?
• STILL A RESEARCH TOPIC TO BE PROVEN

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Cognitive and reconfigurable Radio(1)

• Essay of definition
• Intelligent wireless communication
• Aware of its surrounding environment
• Able to learn
• Able to adapt its internal states (modulation,
  rates, band, power.)in real time
• Objectives
• Highly reliable communications whenever and
  wherever needed
• Efficient utilization of radio spectrum
• Reference S. Haykin Cognitive radio Brain
  empowered wireless communications , IEEE J. on
  Select. Areas in Com., February 2005.

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Cognitive and reconfigurable Radio(2)

• Convergence of
• Digital signal processing
• Ressouce allocation strategies
• Machine learning
• Computer software and hardware
• Today effort is on Software Define Radio to build
  terminal able to adapt rapidely to
• Different radio interfaces (including different
  bands) the goal is to have a sofware adaptable
  radio receiver
• Reconfigurable for sofware updates ,new
  applications and new services

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Conclusion on new proposals
TECHNICS FOR EFFICIENT SHARING MECHANISMS ARE
COMING NEW METHODS FOR RRM SHOULD BE
INTRODUCED PROACTIVE STEPS MUST BE INITIATED
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Possible evolutions of RRM(1) Some (nearly)
obvious first conclusions

• 1- Simple continuation of the regulatory
  framework is absurd
• 2- Overall rapid change is impossible
• 3- A pure economic liberal market would be a
  disaster
• 4- Technical warrantied protection is impossible
• 5- Adaptativity to rapidely changing situation is
  required
• There is no simple solution

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Possible evolutions of RRM(2) The impossible
ultimate solution

• 1- Dense utilisation of the spectrum means
  reducing protection margins, reuse distances,
  guard bands or guard times so increase the
  interferences and saturation situations
• 2- Optimisation creteria for all actors are
  contradictory and trade-offs are necessary
• 3- Optimisation should be at all receivers level
  while constraints are set at transmitters level
  complexity is rapidely growing
• No unique solution but several evolutionary
  paths

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Possible evolutions of RRM(3) Necessity of a
technical/economic solution

• EFFICIENCY SHOULD BE PROMOTED
• 1- Example 1 Cost of frequency should not be
  flat but depend on geography, on time, on band,
  on traffic .in order to force a better
  efficiency
• 2- Example 2 A system requiring a high
  protection should pay more than a system
  requiring a lower protection
• 3- Example 3 A system limiting its interference
  power over a limited area should pay less than
  another radiating in all directions
• Money can be the instrumentnot just the result
  of a trade.

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New trends on RRM(4) Necessity of a
technical/economic solution

• INNOVATION, RISK SHOULD BE REWARDED NOT FORCED
• 1- Example 1 GSM standard was required for 2G
  no CDMA was introduced in Europe.
• 2- Example 2 UMTS was forced politically with
  frequency squeeze and high frequency tags is
  there a solid market?
• 3- Example 3 Bluetooth, WiFi, Wimax, Zigbee
  ..are labels on standards and open to many
  technical variations.
• The right balance of technical constraints is
  difficult to assess may be competing detailed
  labels

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Towards a multilevel sharing strategy(1)

• Sharing is presently quite timid in
  RRM
• Time, Frequency, Geographic zone, power are
  shared but with the idea of  orthogonality 
  (perfect separation) or at least a wide margin.
• Computation is done at worst case conditions with
  QoS targets so at very limited risk
• For example TDMA,CDMA, PAMR, DECT, GSM or WiFi
  Bands shares with military in France, Ad-Hoc
  systems in the same location (eg Bluetooth,
  WiFi), UWB
• With general sharing the margin must be reduced
  and risks are growing

• Sharing principles
• Group many radio access systems with many bands
• Set strategy in case of saturation priorities,
  lower QoS
• Interference temperature could be the underlying
  concept but without concessionary

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Towards a multilevel sharing strategy(2)

• Possible classes
• Common unlicensed bands (no fee-no protection)
  such as ISM bands
• Same standard but different operators could be
  the case with GSM or UMTS
• was planned for DECT public systems
•  polite protocols  to facilitate sharing
• Transmit Power Control (TPC) Dynamic Frequency
  Selection (DFS)
• Common pilot channel
• Spectrum Shaping
•  interference temperature limit  with probably
  several levels such as with or without location
  knowledge, with or without captors network.

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Towards a minimum world unified framework

• States cannot act independantly a worldwide
  framework is necessary not just recommandations
  and  loose  regulations.
• Common base for spectrum pricing
• Identification of bands for classes of systems
  (not services)
• International refarming

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Radio access platforms (1)

• WAPECS(Wireless access platform for electronic
  communication systems)
• Goals (current study at EU Radio Spectrum Policy
  Group)
• 1- Equal and fair conditions for all regardless
  of technologies and bands
• 2- Harmonisation where useful
• 3- Maximum flexibility
• 4- Gradually absorb legacy
• Spectrum fee, Licences duration, Coverage
  constraints and Country discrepencies

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Radio access platforms (2)
               

A UNIFIED REGULATORY REGIME ?
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Radio access platforms(3)

• gtWAPECS all public radio access communication
  networks play a direct role in the information
  society development, regardless of bands, or
  technology.
•  gtDifferent WAPECS platforms may provide mobile,
  portable, or fixed access, for a range of
  electronic communications services
• gt For converged applications, WAPECS may use
  frequencies from allocations other than the core
  service, eg. use of broadcast spectrum to support
  mobile applications (with/without return channel)
  and vice-versa

A HIGH POTENTIAL TOWARDS A UNIFIED REGULATORY
REGIME ?
47
Radio access platforms(4)

• Personal views on WAPECS
• Different groupings may be of interest depending
  on the sharing capability, technology
• Example platform based on common signalling
  channel
• In line with horizontal new organisation of
  telecom service oriented (and not network)
• High level of adaptivity (new networks, new
  bands)
• Reduction of number of transmitting sites (cost ,
  environment)
• Present architecture of systems (specific) may
  not survive
• May need cognitive radio terminals

A new way to develop radio system may be the
consequence.
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FEES for incentives

• Fees should pay for administrative costs
• Fees can be used as incentives for efficient use
  of spectrum for overall benefit
• -all users should pay
• -level of sharing should decrease fees
• -pollution level could be basis for fees
• (example reduced powers, sharp radiating beams,
  high sensitivity receiversreduce pollution and
  should be encouraged)
• -taxes could be limited to revenues

Economic forces should be used for efficiency
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Necessary refarming funds

• Any radio system is installed for a long period
  and the allocated resources may become
  inappropriate after a certain time.
• Any licence period should be long enough to
  justify the heavy investments
• As a compromise subsidized refarming should be
  largely used at national, regional or
  international levels.
• Refarming can appear at a large scale with
  important refarming funds at all levels.

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Use bands for range Use bandwith for rate

• Bands are allocated more or less by  chance 
• availability, status, history but seldom by
  true merit
• Example 1- Range of cellular systems are from 10
  meters to 30 kms
• Bands adapted to the range would be more
  efficient
• Example 2- Use mm bands for PAN, SRD. Etc
• ISM is used because it is a common
  international band (no license)
• Example 3CDMA was presented for its better
  efficiency than TDMA but it appears now that
  there is no such gap.
• Example 4 UWB is introduced because spectrum is
  badly used but is it the best way to use it?
• BANDS bear technical valuenot just Hz

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CONCLUSION

• Radio Resource Management is today at breaking
  point new methods are necessary for a more
  intense (sharing)frequency allocation
• Technical solutions are discussed and should be
  introduced progressively with classes of systems
  Access platforms with some level of interference
  temperature mechanism is the probable way ahead
• Spectrum pricing and traffic fees may become key
  instruments for incentives and refarming actions
• A binding worldwide framework should be
  introduced
• This will impact the organisation of future
  systems

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RECENT TRADE PROPOSALS 1-Why paying?
 It is given by nature so it should be free 
1- Pricing YES or
NO? There are costs for management control,
refarming, studies.. It has a
valueso a price You dont
pay for airetc Every user should pay a fee
based Military, police..etc do not on
spectrum value have to pay It is an
incentive for efficency PROPOSAL ALL
SPECTRUM USERS SHOULD PAY AND USE (eventually
some subsidized)


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RECENT TRADE PROPOSALS 2-spectrum trading
 Is spectrum a good as any other? 1- Beauty
contests or
Auctions? Serves best general interest
Economic efficiency Advantage to incumbent and
Fair and transparent nationals
Need more offers than packs
Easy revenues for
governments Difficulty to invest for
operator Both result of present
situationfor 20 years PROPOSAL FAIR BEAUTY
CONTESTS and limited AUCTIONS


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RECENT TRADE PROPOSALS 3-spectrum second market
 Since you pay, you own the spectrum and can
sell it  1- NO or
YES? General interest may
Economic efficiency not be satisfied
Fair and transparent Open to Stock Exchange
Flexibility variations PROPOSAL NO
SECONDARY MARKET- RETURN TO PRIMARY


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PPM Modulation
Tf
Durée impulsion lt 1 ns (ex 0.8 ns)

• (k) index de la source
• Tf durée trame (ex 0.1 ms)

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PPM Modulation
Tf
Durée impulsion lt 1 ns (ex 0.8 ns)

• (k) index de la source
• Tf durée trame (ex 0.1 ms)

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Coding for ramdomized pulses
1
2
3
3
2
1
Example with a code with 3 values)

• "Time Hopping code" of source k
• nominal delay
• order of magnitude /- 10 ns

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Modulation PPM, la modulation
TsNsTf
1er symbole
2ième symbole
Exemple avec un "étalement" de deux symboles sur
3 impulsions (signal d'une seule source)

• décalage pour un symbole / position nominale
• partie entière de j sur Ns
• le j/Ns ième symbole de la source k
• nombre d'impulsions/symbole (ex Ns100)

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PPM Modulation PPM with multiple access
k 1
k 2
k 3
Example with 3 sources

• Ns nomber of sources