Problems and solutions For any given solution, a frequency planner can find a problem.

Problems and solutions

For any given solution, a frequency planner can find a problem

Problems and solutions

For some problems a frequency planner can find a solution

Problems and solutions

● We have been dealing with a planning exercise● The purpose was to TEST:

Problems and solutions

● We have been dealing with a planning exercise● The purpose was to TEST:

– input data mechanism

Problems and solutions

● We have been dealing with a planning exercise● The purpose was to TEST:

– input data mechanism– computer methods and implementation

Problems and solutions

● We have been dealing with a planning exercise● The purpose was to TEST:

– input data mechanism– computer methods and implementation– reality

Problems and solutions

● We have been dealing with a planning exercise● The purpose was to TEST:

– input data mechanism– computer methods and implementation– reality

● planning assumptions

Problems and solutions

● We have been dealing with a planning exercise● The purpose was to TEST:

– input data mechanism– computer methods and implementation– reality

● planning assumptions● implications of input data

Problems and solutions

● In such a complex process– it is inevitable that there will be software problems – it is inevitable that software problems will take time to

resolve – it is almost inevitable that additional problems will be

introduced during the process of extending the software

– it is inevitable that there will be some human errors when applying the software

Problems

● It may be useful to illustrate some of the problems– in terms of spectrum demand– in a pictorial manner

● This makes it more personal● We have heard that there can be many more than

100 mutually incompatible requirements to be accommodated in 49 channels

● This is what they look like for three geographic areas

● It must be noted that due to display limitations it cannot be guaranteed that all of the coverages in these areas have been shown, nor can it be guaranteed that all of them are mutually exclusive

● It must also be noted that any of the contours shown can actually represent multiple (identical) coverages which have been superimposed

Problems

● There is no obvious real solution that can be offered to solve this problem

● The 'solution' of the 1987 HF conference– put everything into the plan even if it means zero

coverage● is assumed to be unacceptable

Problems and solutions

● As there is no single solution, we have to consider a series of small steps

● We just have to hope that this series of small steps will lead to – 'a giant leap forwards'

Problems and solutions

● As there is no single solution, we have to consider a series of small steps

● We just have to hope that this series of small steps will lead to – 'a giant leap forwards'

● It has to be more than just a hope– we need a high degree of certainty

Problems and solutions

● As there is no single solution, we have to consider a series of small steps

● We just have to hope that this series of small steps will lead to – 'a giant leap forwards'

● It has to be more than just a hope– we need a high degree of certainty

● This can only be achieved by building the steps on good engineering principles associated with good will on all sides

Solutions

● None of the small steps is revolutionary● Some of them may need an alternative approach to

be adopted by some administrations– this applies particularly to 'improvement' of input

requirements● (None of the following pictures is intended to

represent any real situations)

Overlapping assignments

Overlapping assignments

● There are two potential sources of problem– the radiated powers may be too high in some cases– the large service areas may be difficult to protect

● If the powers can be reduced, this is a good start● The area to be protected may be reduced by

changing the requirement so that it consists of– an allotment to represent the area to be protected– an assignment to provide the coverage– these two requirements should be linked

Overlapping assignments

● If there is only one assignment, it may be an advantage to submit the requirements as NOT forming an SFN

● This is a special configuration,having the advantage that– the area of the allotment is regarded as receive only – it

does not cause any additional interference– the assignment is regarded as transmit only – it does

not increase size of the area to be protected

Overlapping allotments

● When proposing allotments, there is a temptation to provide some extra coverage– just to be on the safe side

Overlapping allotments

Overlapping allotments

● The main problem here is that there is increased difficulty in providing protection

● The distance to any re-use of any of the channels is then increased

● Perhaps the service areas can be re-defined so that there are no overlaps

Non-overlapping allotments

Different targets

● Suppose that there are different coverage targets on each side of a national boundary– One country wants portable indoor reception– The other country wants fixed outdoor reception

Different targets

Different targets

● The interference situation is not symmetrical● It may be difficult to reach agreements between

the two administrations● Perhaps portable indoor reception is not needed

throughout the entire allotment area● One solution is to try a linked allotment and

assignment submitted as an SFN

Different targets

Errors

● It is essential for administrations to check what the result of their submissions really is

● There can be major surprises● Some errors in defining allotment boundaries have

resulted in apparent demands for 20 or more channels for a set of coverages of the same area

● This corresponds to more than 20 'layers' of coverage

● This could apply even at VHF● There are many opportunities for errors

Analogue protection

● In many cases there are no channels available for a digital requirement because of the need to protect an analogue assignment

● There is no single solution– consider submitting the digital requirement as a

'conversion'– consider not protecting analogue– (declare that the digital requirement and the analogue

assignment are compatible)

Other service protection

● Sometimes there are no channels for a digital requirement because of the need to provide protection of an OS assignment

● Consider the period for which the OS must remain in operation– perhaps this is so short that there will be no

simultaneous operation– declare the digital requirement and the OS as

compatible

Administrative declarations

● These can provide a significant improvement in a plan

● They must be used carefully– ensure that their use will not lead to a subsequent

coverage loss

Administrative declarations

● They must be submitted carefully– they have a unidirectional effect; take care that both

directions of interference are considered– take care that all relevant pairs of requirements are

dealt with– don't assume that linked requirements will be

automatically taken into account

Administrative declarations

● They must be submitted carefully– they have a unidirectional effect; take care that both

directions of interference are considered– take care that all relevant pairs of requirements are

dealt with– don't assume that linked requirements will be

automatically taken into account – THEY WON'T BE