Approaches to Frequency Planning for RRC-04/05

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Approaches toFrequency Planning for RRC-04/05

• Nigel Laflin
• Rapporteur for Chapter 3 of the TG6/8 report

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Protection of analogue television, digital
broadcasting and other services

• Analogue television
• Need to address conditions for the protection of
  existing stations
• Administrations should indicate which of their
  existing and planned stations should be protected
• Administrations should ensure that their entries
  in ST61, GE89 and Master Register reflect the
  actual co-ordinated situation (see table A.3.4-1
  of TG 6/8 report)
• Digital broadcasting
• Need to address conditions for digital
  terrestrial television broadcasting currently
  recorded in the Master Register with favourable
  findings
• Other services
• Need to consider conditions for other services
  sharing the frequency bands 174 to 230 MHz and
  470 to 862 MHz

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Coordination procedures (1)

• The new Agreement should include provisions
  and/or procedures for
• Coordination of unresolved cases
• Modifications to the Plan
• The transition from analogue to the all digital
  broadcasting situation
• Inter/intra-service protection of analogue
  television, digital broadcasting and other
  primary services see table below

Source of Interference Services to be protected Services to be protected Services to be protected Services to be protected
Source of Interference Analogue TV Bands III, IV, V Digital TV Digital Sound Other Services
Analogue TV assignments ST61/GE89 provisions To be established To be established ST61/GE89 provisions
Digital TV allotments/ assignments To be established To be established To be established To be established
Digital Sound allotments/assignments To be established To be established To be established To be established
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Coordination procedures (2)

• Coordination distances
• Identify which administrations might be affected
  when an administration proposes to modify a plan
  by changing the characteristics of an existing
  assignment or allotment, or add a new assignment
  or allotment
• Examples for assignment planning are
• Tables giving limiting distance as a function of
  effective radiated power, effective antenna
  height and the nature of the path under
  consideration (ST61 Agreement)
• Tables of distances between station in question
  and any point on the boundary of any other
  administration (GE89 Agreement)
• And for allotment planning
• The coordination distances based on standardised
  transmission reference values and separation
  distances (RJ88 Agreement)
• Test points
• Test points may be used in planning to describe
  coverage of coordinated stations, allotment
  areas, assignment requirements, or the boundary
  of other services to be protected

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Planning principles - general

• Planning process based on an inventory of
  administrations requirements
• Equitable access to the frequency resources but
  account taken of the technical and economic
  constraints
• Use of the minimum number of channels to satisfy
  requirements
• Each administration to decide on compatibility of
  digital plan with existing services in its own
  country and to indicate which existing and
  planned stations should be protected
• Proposed digital allotments/assignments open to
  bilateral or multilateral negotiation between
  administrations concerned
• Based on results of planning exercises
  incompatibilities should be resolved by
  bi/multilateral discussions prior to Second
  Session
• Planning provisions for countries not present
• No account to be taken of low power digital
  assignments in the planning process these can
  be entered later

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Planning Bases

• Procedure for production of a plan
• Compatibility analysis to identify
  incompatibilities arising from input requirements
  - appropriate responses to these problems would
  be considered by the Planning Conference
• Synthesis process could be used to permit the
  rapid development of possible alternative
  frequency plans
• Approaches to the Plan
• Modification of the existing Plans may not lead
  to an optimum plan for some countries but easy to
  implement (e.g. via the conversion of analogue
  assignments to digital assignments)
• Completely new plan greater spectrum
  utilisation efficiency but difficult to implement
• Combination of both likely scenario to
  facilitate the requirements of all countries in
  the planning area

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Planning Scenario 1
All existing or planned analogue assignments
would need to be protected from new digital
assignments indefinitely

• Administration can decide for itself when any of
  its new digital requirements can be brought into
  operation
• The rights for ST61 and GE89 plans are retained
• No constraints on the transition procedure
• Minimal impact on the analogue services
• Least potential for future digital development
• May not offer the opportunity for full digital
  coverage

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Planning Scenario 2
All existing or planned analogue assignments to
be protected from new digital assignments, but
the analogue assignments would be converted to
digital and will form part of all-digital plan

• Administration can decide when its digital
  requirements can be brought into operation
  analogue assignments converted to digital
  assignments
• The rights for ST61 and GE89 plans are retained
• No constraints on the transition procedure
• Reduced opportunities for digital services
• The spacing between digital stations (based on
  analogue network) may not be optimal
• Potential interaction between digital
  requirements and assignments resulting from
  analogue conversions must be taken into account
  during the planning process

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Planning Scenario 3
Analogue assignments can be converted to digital
and incorporated in the new digital plan as
required no attempt to protect existing or
planned analogue assignments

• Administration can decide for itself when new
  digital requirements are brought into operation
  provided that unwanted interference is not caused
  to analogue assignments of a neighbour
• High potential for future digital development
• If required, the rights for ST61 and GE89 plans
  are retained
• Use of synthesis planning approach could
  facilitate a near ideal Plan
• Transition process would require coordination
  with neighbouring countries
• Necessary for the Agreement to contain procedures
  to allow for a transition to the all-digital Plan

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Planning Scenario 4
New Plan no need to retain or protect existing
or planned analogue assignments

• Greatest potential for future digital development
• May have an application in situations where there
  are currently unused channels
• Administration will have little or no freedom to
  decide for itself when any given station could be
  brought into operation as considerable
  interaction with neighbouring administrations
  could be required
• Necessary to develop complex transition
  procedures
• No rights for ST61 and GE89 plans are retained

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Planning Elements

• First layer
• What type of service is required DVB-T, T-DAB?
• What type of reception is required fixed,
  portable?
• Territorial coverage complete, urban areas,
  regions?
• Which existing and planned elements should be
  protected?
• Second layer
• Which DVB-T variant should be employed?
• Which network characteristics should be chosen
  antennas, distance between stations?
• Third layer
• Which network configuration should be employed
  MFN/SFN?
• Should entries in the Plan be allotments or
  assignments, or both?

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Planning approaches Assignments

• In the past, terrestrial television planning in
  Europe has been by way of assignment conferences
• The assignment plan provides a frequency for each
  station at the completion of the planning
  process the locations and characteristics of the
  transmitters are known
• Assignment planning, based on a lattice
  structure, is appropriate where transmitter sites
  can be assumed to have the same characteristics
• The transmitters can be brought into service
  without further coordination
• A lower limit for the radiated power is normally
  defined for stations within the planning process

Examples of assignments used in lattice planning
(ST61)
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Planning approaches Allotments

• In general nothing is known of the actual
  location of the transmitter sites, or of the
  specific transmission characteristics to be used
• The parameters required are a definition of the
  area to be covered, the channel and the
  interference potential of the allotment
• In order to carry out planning it is necessary to
  define reference transmission conditions to
  calculate potential interference and facilitate
  compatibility calculations
• The allotment plan provides frequencies to be
  used in particular areas without specifying the
  stations to which the frequencies are assigned

Band III allotments areas from the Wiesbaden 1995
Plan
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Allotment planning reference networks

• Reference networks are required to assess the
  outgoing interference potential with particular
  reference to
• calculating the compatibility between allotment
  areas including separation distance
• the generation of a set of calculation test
  points for the later conversion of allotments
  into assignments

Separation distances between reference networks
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Assignment and/or allotment planning

• Assignment planning is preferable
• Where transmitter infrastructure is known
• In the case of MFN or small SFN planning
• Allotment planning is preferable
• Where the transmitter infrastructure is not known
• If channels are available for planning DVB-T
  services which are required to cover the whole
  of a larger area
• If great potential for flexibility in terms of
  the implementation of transmitter networks
  within the Plan is desired
• If portable reception is a prime requirement
• General conclusion
• Whilst allotment based planning requires more
  work after the conference, there is a major
  advantage in terms of flexibility in the
  subsequent development of transmitter networks
  and greater scope to accommodate future digital
  system developments

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Planning method

• Lattice based a systematic and geographically
  regular distribution of frequency resources over
  an area
• Lattice independent a pseudo-random but
  spectrum utilization efficient distribution of
  frequency resources over an area

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Lattice-based methods

• Lattice based methods assume
• Geometrically regular lattices, linear
  channel-distribution schemes
• All transmitters are identical, their powers and
  antenna heights being the same
• Antenna radiation patterns are omni-directional
  in the horizontal plane
• Radio wave propagation losses are not a function
  of propagation direction and frequency
• Lattice based methods have been applied with
  success for past planning/re-planning of AM or FM
  sound or televisions services where
• Empirical methods were difficult to implement
• When some uniformity of standards exists for the
  services to be planned
• There is freedom in assigning any frequency to
  any transmitter

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Lattice-independent methods

• Lattice-independent planning makes no assumption
  about the uniformity of the network and this can
  be a significant advantage where
• Coverage requirements depart from any
  approximation to a regular lattice useful for a
  mixture of large and small areas requiring
  different programmes, and in areas where several
  countries meet and each has adopted a different
  coverage philosophy
• A set of assignments needs to be added into an
  existing planned broadcasting situation, or there
  are analogue stations in the same part of the
  spectrum
• Furthermore lattice-independent planning
• can permit a more-or-less continuous process of
  transition from analogue only
• represents a close approach to optimum use of the
  spectrum when coverage areas are non-uniform

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Choice of planning method or methods

• Lattice based methods have successfully provided
  the basis for most of the past broadcasting plans
  and could be adopted for use for digital
  broadcasting planning in areas of relative
  uniformity of requirement characteristics
• Lattice-independent planning seems highly likely
  to provide an optimum means to achieve both the
  desired coverage and the most efficient use of
  the available spectrum in areas of nonuniform
  requirements for digital television and/or sound
  broadcasting (very different sizes of coverage
  area and various reception conditions), and in
  areas where there are already networks of
  analogue stations

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Example of a lattice-independent planning process
compatibility analysis and synthesis

1. Submission of the input requirements for the
   digital broadcasting services
2. Identify the analogue broadcasting services and
   other services to be protected
3. Perform compatibility analysis
4. Assess the results from step 3
5. Allow for administrative input concerning
   compatibility between requirements
6. Perform synthesis to produce a plan
7. Review the results and loop back to step 3 if the
   desired result is not achieved
8. Agreement of the final plan

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Network structures and configurations

• In principle there are two types of terrestrial
  digital broadcasting networks to be considered
• multi-frequency networks (MFN) which allow the
  same or different programmes to be carried by
  individual transmitters using different
  frequencies
• single frequency networks (SFN) in which
  distributed emission is implemented whereby
  coverage is provided by multiple transmitters
  operating on the same frequency and carrying the
  same programmes
• The network configurations for digital
  terrestrial broadcasting services can be
  implemented as MFN, as SFN or as mixed networks
  consisting of MFNs and SFNs
• The type of network implemented depends on the
  availability of frequencies, the type of coverage
  required, the number of multiplexes to be
  provided and may depend on national constraints
  or strategies

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Multi Frequency Networks (MFNs)
Coverage of service area
Border of service area

• Each transmitter uses a different frequency
  channel (Cx), acting independently and having its
  own coverage area
• Re-use of channels is possible given sufficient
  geographical separation

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Single Frequency Network (SFN)
Coverage of service area
C1
C1
C1
C1
C1
C1
C1
C1
C1
C1

• All transmitters of the network use the same
  frequency channel
• The transmitters provide a common coverage area
  and cant be operated independently they must
  carry identical multiplex content

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Considerations concerning MFN and SFN
configurations

• MFN
• A large part of the existing analogue network
  infrastructure may be re-used particularly for
  fixed reception this has cost-saving
  implications for the broadcaster and can also
  provide benefits for the viewer
• SFN
• The same frequency must be available over the
  whole coverage area
• Existing analogue network infrastructures can be
  re-used although additional transmitters may be
  required to avoid self-interference
• SFN planning allows for a more homogeneous field
  strength distribution for portable and mobile
  reception
• Mixed MFN-SFN
• Within an MFN of main stations, lower power
  stations may complete the coverage using the same
  frequency as the associated main station
• An MFN structure for transmitting a national
  multiplex and an SFN structure for transmitting a
  regional multiplex
• This type of mixed network scenario could arise
  from different approaches in adjacent countries

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Other information available in Chapter 3

• A method for establishing the coverage area of
  coordinated (existing or planned) analogue
  stations
• Details of the frequency bands used for
  television broadcasting within the planning area
• Information concerning relevant digital
  terrestrial systems for television (ATSC, DVB-T
  and ISDB-T) and sound (T-DAB and ISDB-TSB)
• An overview of digital broadcast systems intended
  for or already in use in the Bands III, IV and V
  (Annex A.3.3) which indicates that
• For Bands IV/V all countries with an entry intend
  to use DVT-T
• For Band III the vast majority of European
  countries intend to use TDAB and DVB-T whilst
  for other parts of the planning area the current
  trend is towards DVB-T only

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The End

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