bal 1 the radio spectrum: utilisation and management part 2 les barclay

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The Radio Spectrum: The Radio Spectrum:

utilisation and managementutilisation and management

part 2part 2

Les BarclayLes Barclay

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Regulations for transmissions form satellites and of the use of the GSO

Satellites operate in space, beyond the air-space controlled by individual national administrations.

However:- satellites could cause widespread and serious interference to other satellite & terrestrial

radio systems,

- the GSO is a limited resource

There is a need to regulate both GSO & radio characteristics

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The ITU Radio Regulations specify the way in which the both the space and earth stations may use the radio spectrum and also regulate the use of positions in the GSO.

Use of the spectrum is a matter of national sovereignty, but in accordance with international treaty.

However, national authority does not extend to satellite heights!

Moreover, communication satellites are owned, in the main, by commercial entities and are launched from facilities only located in a few countries.

.

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Transmissions from space stations seem to be difficult to regulate.

Little incentive for administrations to devote resources to the coordination of frequencies and orbit positions for space stations since they do not contribute any licence fees.

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Who is responsible?Who is responsible?

- the owner of the space station?

- the administration of the country from which it was launched?

- the country which hosts the control facility?

each space station is notified to the ITU by an administration

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The Radio Regulations require administrations to use established coordination techniques

for earth stations and for the GSO

or criteria based on PFD and probability estimates based on satellite positions.

Operators of satellite networks also need to have assurance that their quality of service will be maintained.

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recognised spectrum access

In the UK there is a procedure for “recognised spectrum access”

subject to a fee (corresponding to a licence fee)

the administration will undertake to take part in coordination procedures, etc.,

as if the space station were under the authority of the administration

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Radio RegulationsRadio Regulations

Provide World-Wide agreement on the use, Provide World-Wide agreement on the use, coordination and regulation of radiocoordination and regulation of radio

Contain the International Table of Radio Contain the International Table of Radio Frequency AllocationsFrequency Allocations

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4.14.1 Member States shall endeavour to limit the Member States shall endeavour to limit the number of frequencies and the spectrum used to number of frequencies and the spectrum used to the minimum essential to provide in a satisfactory the minimum essential to provide in a satisfactory manner the necessary services. To that end they manner the necessary services. To that end they shall endeavour to apply the latest technical shall endeavour to apply the latest technical advances as soon as possible advances as soon as possible

4.24.2 … in assigning frequencies to stations which … in assigning frequencies to stations which are capable of causing harmful interference to are capable of causing harmful interference to services … of another country, such assignments services … of another country, such assignments are to be made in accordance with the Table of are to be made in accordance with the Table of Frequency Allocations and other provisions of these Frequency Allocations and other provisions of these Regulations Regulations

4.34.3 Any new assignment or any change of Any new assignment or any change of frequency … shall … avoid causing harmful frequency … shall … avoid causing harmful interference … interference …

4.44.4 … shall not assign to a station any frequency … shall not assign to a station any frequency in derogation of either the Table of Frequency in derogation of either the Table of Frequency Allocations … or other provisions … except on the Allocations … or other provisions … except on the express condition … shall not cause harmful express condition … shall not cause harmful interference interference

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Frequency block allocations Frequency block allocations – frequency bands identified in – frequency bands identified in the Radio Regulations for use by one or more radio services;the Radio Regulations for use by one or more radio services;

Allotment plansAllotment plans – individual channels in a band allotted to – individual channels in a band allotted to specific countries for use for specific purposes, specific countries for use for specific purposes,

A-priori frequency assignment plans A-priori frequency assignment plans – where the use of a – where the use of a band is planned as a whole on an agreed uniform basis;band is planned as a whole on an agreed uniform basis;

Modification procedures Modification procedures – to provide a method of including – to provide a method of including additional transmitters within an a-priori planadditional transmitters within an a-priori plan

Defining maximum technical parametersDefining maximum technical parameters, such as , such as radiated power or power flux densityradiated power or power flux density

Frequency coordination Frequency coordination – a proposed new transmitter is – a proposed new transmitter is notified & agreed by the authorities in other countries which notified & agreed by the authorities in other countries which may be affectedmay be affected

Technical assessment Technical assessment – perhaps within one country where – perhaps within one country where there is knowledge of existing servicesthere is knowledge of existing services

Field trials Field trials – the use of test transmissions to ensure – the use of test transmissions to ensure compatible workingcompatible working

Hierarchy of frequency sharing Hierarchy of frequency sharing approachesapproaches

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A-priori planningA-priori planning

Possible to maximise spectrum use by closely Possible to maximise spectrum use by closely packing the requirementspacking the requirements

Less and less likely that a blank portion of the Less and less likely that a blank portion of the spectrum will be availablespectrum will be available

Little flexibility for modification or for the Little flexibility for modification or for the introduction of new requirements at a later dateintroduction of new requirements at a later date

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The Broadcasting Satellite ServiceThe Broadcasting Satellite Service

RR 1.38 defines the (terrestrial) broadcasting RR 1.38 defines the (terrestrial) broadcasting service as “transmissions intended for direct service as “transmissions intended for direct reception by the general public”.reception by the general public”.

RR 1.39 for the broadcasting-satellite service RR 1.39 for the broadcasting-satellite service (BSS) is broader, to take account of community (BSS) is broader, to take account of community antenna receiving systems:antenna receiving systems:

“ “a radiocommunication service in which signals a radiocommunication service in which signals transmitted by space stations are intended for transmitted by space stations are intended for the direct reception of the general public. In the the direct reception of the general public. In the BSS the term “direct reception” shall encompass BSS the term “direct reception” shall encompass both individual reception and community both individual reception and community reception”.reception”.

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Satellite broadcast receptionSatellite broadcast reception

RRs 1.129 & 1.130 define: RRs 1.129 & 1.130 define: Individual Reception. Individual Reception. “The reception of “The reception of

emissions from a space station in the BSS by emissions from a space station in the BSS by simple domestic installations and in particular simple domestic installations and in particular those possessing small antennas.”those possessing small antennas.”

Community Reception. Community Reception. “The reception of “The reception of emissions from a space station in the BSS by emissions from a space station in the BSS by receiving equipment, which in some cases may receiving equipment, which in some cases may be complex, and have antennas larger than those be complex, and have antennas larger than those used for individual reception, and intended for used for individual reception, and intended for use by a group of the general public at one use by a group of the general public at one location or through a distribution system covering location or through a distribution system covering a limited area.”a limited area.”

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BSS AllocationsBSS Allocations

The primary BSS allocations have been made at The primary BSS allocations have been made at 12 GHz for individual reception (although 12 GHz for individual reception (although community reception is not excluded);community reception is not excluded);

Region 1; 11.7 – 12.5 GHzRegion 1; 11.7 – 12.5 GHzRegion 2; 12.2 – 12.7 GHzRegion 2; 12.2 – 12.7 GHzRegion 3; 11.7 – 12.2 GHzRegion 3; 11.7 – 12.2 GHz

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FREQUENCY ASSIGNMENT FREQUENCY ASSIGNMENT PLANNING FOR THE BSSPLANNING FOR THE BSS

A priori planning for the BSS in frequency A priori planning for the BSS in frequency bands shared with other servicesbands shared with other services

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Stage 1Stage 1

Sharing services have “permitted” status in advanceSharing services have “permitted” status in advance of drawing up the plan. Assignments for these of drawing up the plan. Assignments for these services do not get primary status until the services do not get primary status until the assignment plan has been made.assignment plan has been made. Or: add footnoteOr: add footnote

““in the band 11.7 – 12.5 GHz in Regions 1 and 3, thein the band 11.7 – 12.5 GHz in Regions 1 and 3, thefixed, fixed-satellite, mobile except aeronautical fixed, fixed-satellite, mobile except aeronautical mobile and broadcasting services, in accordance mobile and broadcasting services, in accordance

with with their respective allocations, shall not cause harmful their respective allocations, shall not cause harmful interference to broadcasting satellite stations interference to broadcasting satellite stations operating in accordance with the provisions of operating in accordance with the provisions of Appendix 30.”Appendix 30.”

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Stage 2Stage 2

All countries state requirements for All countries state requirements for number number

of channels and service area.of channels and service area.

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Stage 3Stage 3a)a) Define performance objective for service to end Define performance objective for service to end

user, with equipment with agreed standards of user, with equipment with agreed standards of performance. performance. - expressed in terms of demodulated-signal-to- - expressed in terms of demodulated-signal-to-

(noise plus interference) (noise plus interference) - split between feeder link (up) & BSS link (down) - split between feeder link (up) & BSS link (down) and between noise and interferenceand between noise and interference

b) Relate the –3 dB footprint to the service area.b) Relate the –3 dB footprint to the service area. - c- calculate in-beam gain of each satellite alculate in-beam gain of each satellite transmitting antennatransmitting antenna - specify receiving on-beam gain, noise factor, - specify receiving on-beam gain, noise factor,

out-out- of-beam gain roll-off characteristics & cross-of-beam gain roll-off characteristics & cross- polar rejectionpolar rejection..

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Stage 3 (cont)Stage 3 (cont)

c)c) prepare a matrix of isolation provided by prepare a matrix of isolation provided by the antennas between every pair of service the antennas between every pair of service areas as a function of satellite orbital areas as a function of satellite orbital position.position.

d)d) determine frequency channel arrangement determine frequency channel arrangement and policy on down-path PFDand policy on down-path PFD

e)e) select the type of modulation, standard carrier select the type of modulation, standard carrier parameters, picture standards, receiver parameters, picture standards, receiver

selectivity selectivity standards etc.standards etc.

Isolation provided by channel separation can then be Isolation provided by channel separation can then be calculated.calculated.

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Stage 4Stage 4

Prepare an assignment plan, assigning Prepare an assignment plan, assigning channels channels

and orbital locations to all the requirements and orbital locations to all the requirements in in

such a way that the isolation provided by such a way that the isolation provided by

antennas, plus the isolation provided by antennas, plus the isolation provided by channel channel

separation, permits the performance separation, permits the performance objective objective

to be obtained. to be obtained.

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Stage 4: - if the assignment is not Stage 4: - if the assignment is not satisfactory:satisfactory:

- Improve the efficiency with which service areas - Improve the efficiency with which service areas have been coupled with orbital positions and have been coupled with orbital positions and channels, orchannels, or

- Make antenna performance standards more - Make antenna performance standards more stringentstringent

- Make more stringent the minimum requirements - Make more stringent the minimum requirements for some of the various factors which determine for some of the various factors which determine the isolation provided by channel separation, orthe isolation provided by channel separation, or

- Accept worse performance, or- Accept worse performance, or- Reduce the requirementsReduce the requirements

- Re-iterate the planning process until a feasible - Re-iterate the planning process until a feasible plan is achieved and agreed.plan is achieved and agreed.

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Stage 5Stage 5

Prepare a feeder link plan.Prepare a feeder link plan.

The arrangement of channels may be the The arrangement of channels may be the same as for the down-link plan, but the same as for the down-link plan, but the determination of emission parameters may determination of emission parameters may be more complex.be more complex.

(17.3 – 18.1 GHz(17.3 – 18.1 GHz

Detailed assignment plans for the above bands Detailed assignment plans for the above bands have been prepared and are in RR App. 30A)have been prepared and are in RR App. 30A)

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Stage 6Stage 6

3 sets of procedures then required for the 3 sets of procedures then required for the operation of the plan:operation of the plan:

(a)(a) A procedure for amending the plan, for use A procedure for amending the plan, for use when a country’s requirements have changed, when a country’s requirements have changed, but respecting the rights of other countries but respecting the rights of other countries holding assignments in the planholding assignments in the plan

(b)(b) A procedure for registering planned A procedure for registering planned assignments to the BSS in the MIFR once they assignments to the BSS in the MIFR once they have been brought into service.have been brought into service.

(c)(c) A procedure for registering in the MIFR A procedure for registering in the MIFR assignments to stations of the other services assignments to stations of the other services with nominal equality of allocation, and also with nominal equality of allocation, and also BSS assignments which are extra to the plan, BSS assignments which are extra to the plan, subject to the protection of planned subject to the protection of planned assignments.assignments.

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The 1977 BSS PlanThe 1977 BSS Plan

a)a) service is to national service areas in almost all service is to national service areas in almost all cases. cases.

- - For large countries, a set of assignments was For large countries, a set of assignments was

made to each time zone in the countrymade to each time zone in the country. . – – 3dB footprint of satellite transmit antenna is 3dB footprint of satellite transmit antenna is

the minimum ellipse circumscribing points to be the minimum ellipse circumscribing points to be specified at the borders of the country, with a specified at the borders of the country, with a minimum beam diameter of 0.6ºfor small minimum beam diameter of 0.6ºfor small countries. But some use of overspill radiation, countries. But some use of overspill radiation, in Europe for countries using the same, or in Europe for countries using the same, or closely related, languages, in particular closely related, languages, in particular German.German.

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The 1977 BSS Plan (cont)The 1977 BSS Plan (cont)

b) Picture standards - 625 or 525-line; sound sub-carrier b) Picture standards - 625 or 525-line; sound sub-carrier

combined with video at baseband, the whole FM on combined with video at baseband, the whole FM on the the

12 GHz carrier.12 GHz carrier.

c) Service planned for “individual reception” (but c) Service planned for “individual reception” (but

performance standards maintained if some countries performance standards maintained if some countries

design networks for “community reception”) design networks for “community reception”)

d) Polarisation discrimination used – with orthogonal d) Polarisation discrimination used – with orthogonal

circular polarisationscircular polarisations..

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e) satellites located at least 15º W of meridian e) satellites located at least 15º W of meridian which which

determines the local time for eclipsedetermines the local time for eclipse

f)f) assumed that most of the circuit degradations, assumed that most of the circuit degradations, due due

to thermal noise, interference, etc., occurred to thermal noise, interference, etc., occurred on on

the down-link path – little margin left for up-the down-link path – little margin left for up-link link

degradationsdegradations

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The 1977 BSS Plan (cont)The 1977 BSS Plan (cont)g)g) satellites clustered at orbit points separated by 6º satellites clustered at orbit points separated by 6º with frequency separation between channel with frequency separation between channel

centres centres of 19.18 MHzof 19.18 MHz

(800 MHz of allocated band divided into 40 (800 MHz of allocated band divided into 40 channels)channels)

All countries have BSS assignments, & all have All countries have BSS assignments, & all have equal number of channelsequal number of channels

5 channels per country in 800 MHz. 5 channels per country in 800 MHz. alternate channels assigned orthogonal alternate channels assigned orthogonal

polarisations, with overlap of outer parts of polarisations, with overlap of outer parts of emission spectraemission spectra

The 5 channels assigned to a country (or to a The 5 channels assigned to a country (or to a time zone) all have same satellite location, time zone) all have same satellite location, same polarisation and all in either the lower or same polarisation and all in either the lower or upper half of the frequency band.upper half of the frequency band.

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h) France: channels 1, 5, 9, 13 & 17; 19º W; RH circ polh) France: channels 1, 5, 9, 13 & 17; 19º W; RH circ pol Germany: 2, 6, 10, 14 & 18; 19º W; LH circ polGermany: 2, 6, 10, 14 & 18; 19º W; LH circ pol Netherlands: 23, 27, 31, 35 & 39; 19º W; RH circ polNetherlands: 23, 27, 31, 35 & 39; 19º W; RH circ pol UK: 4, 8, 12 & 16; 31º W; RH circ polUK: 4, 8, 12 & 16; 31º W; RH circ pol peak frequency deviation - 12 MHz; peak frequency deviation - 12 MHz; necessary bandwidth - 27 MHz.necessary bandwidth - 27 MHz.i)i) User’s receiving system.User’s receiving system.

G/T = 6dB/K; -3dB beamwidth = 2ºG/T = 6dB/K; -3dB beamwidth = 2º

j) j) Satellite transmitting antenna gain corresponding to an Satellite transmitting antenna gain corresponding to an elliptical beam with a –3dB footprint which circumscribes elliptical beam with a –3dB footprint which circumscribes the geographical points which define the service area or the geographical points which define the service area or a 0.6º beam, whichever is broadera 0.6º beam, whichever is broader

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The 1977 BSS Plan (cont)The 1977 BSS Plan (cont)k) Satellite station keeping: E/W; ±0.1º; N/S; ±0.1ºk) Satellite station keeping: E/W; ±0.1º; N/S; ±0.1º beam pointing accuracy; 0.1º of nominalbeam pointing accuracy; 0.1º of nominal

rotation of non-circular beams (due to yaw) <2ºrotation of non-circular beams (due to yaw) <2ºl) Emission parameters.l) Emission parameters.

Pfd, edge of coverage (99% of worst month) -103 dBW/m²Pfd, edge of coverage (99% of worst month) -103 dBW/m² Down-link C/N ratio 14dB, including 0.5 dB due to up-linkDown-link C/N ratio 14dB, including 0.5 dB due to up-link thermal noise (plus interference)thermal noise (plus interference) Down-link C/l ratio: co-channel 31dB; adjacent chan. 15 Down-link C/l ratio: co-channel 31dB; adjacent chan. 15

dBdB m) Entry into force; 1 January 1979m) Entry into force; 1 January 1979n) n) revision; plan & associated provisions “have been prepared revision; plan & associated provisions “have been prepared

in order to meet the requirements of the BSS in the bands in order to meet the requirements of the BSS in the bands concerned for a period of at least 15 years from the date of concerned for a period of at least 15 years from the date of the entry into force of these Final Acts. In any event, the the entry into force of these Final Acts. In any event, the provisions and the associated plan shall remain in force until provisions and the associated plan shall remain in force until their revision by a competent administrative radio conference their revision by a competent administrative radio conference convened in accordance with the relevant provisions of the convened in accordance with the relevant provisions of the Convention in force.”Convention in force.”

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The 1977 BSS Plan (results)The 1977 BSS Plan (results)

Plan undermined by:Plan undermined by:- improvements in receiver technology (lower improvements in receiver technology (lower

noise factor, smaller dishes)noise factor, smaller dishes)

- competitive services in adjacent FSS bands- competitive services in adjacent FSS bands

- new countries- new countries

- inadequate number of channels- inadequate number of channels

New plan and procedure agreed at New plan and procedure agreed at WRC 2000WRC 2000

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Unwanted SatellitesUnwanted Satellites

old satellites, no longer in use and no longer old satellites, no longer in use and no longer controllable, may drift around the GSO and controllable, may drift around the GSO and

interfere with working satellitesinterfere with working satellites..- risk of physical collision- risk of physical collision- interference from an idle satellite emitting - interference from an idle satellite emitting

telemetry and transponderstelemetry and transponders

RR 22.1 “Space stations shall be fitted with devices RR 22.1 “Space stations shall be fitted with devices

to ensure immediate cessation of their radio to ensure immediate cessation of their radio emissions by telecommand, whenever such emissions by telecommand, whenever such cessation is required under the provisions of cessation is required under the provisions of these these

Regulations”Regulations”

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coordinationcoordination

a prioria priori planning - limited - where all requirements planning - limited - where all requirements

can be specified in advance, & where an allocated can be specified in advance, & where an allocated

band is available. Maybe ineffective & inefficient band is available. Maybe ineffective & inefficient

for incorporating change.for incorporating change.

progressive methods for incremental planning new progressive methods for incremental planning new

stations as needed have become much more stations as needed have become much more common. common.

new stations have to be planned to meet sharing new stations have to be planned to meet sharing

limits, or have to be coordinated with existing limits, or have to be coordinated with existing

servicesservices

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Fixed Satellite Service (FSS)Fixed Satellite Service (FSS) subject to a greater degree of international subject to a greater degree of international regulation than any other service regulation than any other service potentially high quality transmission mediumpotentially high quality transmission medium

- but wide open to degradation by interference- but wide open to degradation by interference capable of providing great total capacity,capable of providing great total capacity,

- but may well be insufficient- but may well be insufficient can by-pass established telecommunications can by-pass established telecommunications

carriers.carriers.

How to ensure that all nations have equitable How to ensure that all nations have equitable treatment for national satellite systems,treatment for national satellite systems,

- even if they do not start operating until some - even if they do not start operating until some time in the future time in the future..

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Frequency Sharing between FSS & FSFrequency Sharing between FSS & FS

Almost all FSS allocations shared with FS with equal Almost all FSS allocations shared with FS with equal status. status.

At SHF, FS mostly for radio relay chains.At SHF, FS mostly for radio relay chains.

Interference likely to occur between FSS & FS and Interference likely to occur between FSS & FS and must be kept acceptably low in level.must be kept acceptably low in level.

Most FSS & FS systems used for telephone Most FSS & FS systems used for telephone services, digital service connections or TV services, digital service connections or TV connections, with high quality requirementsconnections, with high quality requirements

Some bands likely to be shared with FS using Some bands likely to be shared with FS using relays relays

from station-keeping high altitude platforms in the from station-keeping high altitude platforms in the stratosphere (HAPS) stratosphere (HAPS)

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Reference Circuits

Terrestrial radio relay system may have a few hops covering a total distance of, say, 100 km; or 100 hops covering 1000s of km;

Whatever the system, noise in a long connection or the ber, due system degradations and interference must not exceed acceptable limits.

Performance and interference of each radio relay hop cannot be determined for that hop or that system alone

There is the possibility that the channels may be made part of a much longer end-to-end connection.

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Hypothetical Reference Circuit

Hypothetical Reference Circuit (HRC) for analogue transmission systems

Hypothetical Reference Digital Path (HRDP) for digital transmission systems.

For radio relay these have a length of 2500 km with various combinations of multiplexing and demultiplexing equipments throughout the length of the system.

For satellite, one hop is assumed

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FDM telephony: 1-min mean power, <20% of any month.

satellite: - 10000 pW0p · radio relay: - 7500 pW0p

· Digital links as part of an ISDN: <10% of any month satellite: BER of 1 per 107; radio relay: BER of 1 per 106

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Interference between stations of Interference between stations of space & terrestrial services may space & terrestrial services may arise by 4 different modes:arise by 4 different modes:

1.1. Satellite transmitters interfere with terrestrial Satellite transmitters interfere with terrestrial station receivers,station receivers,

2. Terrestrial station transmitters interfere with 2. Terrestrial station transmitters interfere with satellite receivers,satellite receivers,

3. Earth station transmitters interfere with 3. Earth station transmitters interfere with terrestrial station receivers,terrestrial station receivers,

4. Terrestrial station transmitters interfere with 4. Terrestrial station transmitters interfere with earth station receivers.earth station receivers.

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Mode 1: Sharing constraints on Mode 1: Sharing constraints on satellite emissions.satellite emissions.

sharing constraints: maximum values of power flux sharing constraints: maximum values of power flux

density, measured in a defined sampling density, measured in a defined sampling bandwidth, at bandwidth, at

any point on the Earth’s surface any point on the Earth’s surface

limit varies with frequency and angle of elevation:limit varies with frequency and angle of elevation:

e.g. - at 4 GHz max. pfd is –142 dB (W/m²) in a 4 e.g. - at 4 GHz max. pfd is –142 dB (W/m²) in a 4 kHz kHz

band at satellite elevation angle of 30º.band at satellite elevation angle of 30º.

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Art. 21 Limits (extract)Art. 21 Limits (extract)

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Mode 2: Sharing constraints on Mode 2: Sharing constraints on terrestrial station emissionsterrestrial station emissions..

a) eirp of FS & MS stations shall not exceed +55 dBW.a) eirp of FS & MS stations shall not exceed +55 dBW.b) power input to antenna of FS or MS station shall notb) power input to antenna of FS or MS station shall notexceed +13dBW below 10GHz, or +10dBW above exceed +13dBW below 10GHz, or +10dBW above 10GHz10GHz

c) between 1 & 10 GHz, terrestrial transmitted beams c) between 1 & 10 GHz, terrestrial transmitted beams shall be at least 2º off direction of GSO, unless eirp shall be at least 2º off direction of GSO, unless eirp < +35 dBW. Or, eirp shall not exceed +47 dBW in any < +35 dBW. Or, eirp shall not exceed +47 dBW in any

direction within 0.5º of orbit, limit rising linearly in direction within 0.5º of orbit, limit rising linearly in dB at a rate of 8 dB per º to +55 dBW at 1.5º away dB at a rate of 8 dB per º to +55 dBW at 1.5º away from orbit.from orbit.d) between 10 & 15 GHz, terrestrial transmitted beams d) between 10 & 15 GHz, terrestrial transmitted beams shall be at least 1.5 º off direction of GSO unless shall be at least 1.5 º off direction of GSO unless eirp < +45 dBW.eirp < +45 dBW.

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Avoiding the GSOAvoiding the GSO

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Modes 3 and 4: Frequency Modes 3 and 4: Frequency coordination.coordination.

Earth stations use high transmitter powers and Earth stations use high transmitter powers and very sensitive receivers. Interference between very sensitive receivers. Interference between earth stations using the same frequency bands can earth stations using the same frequency bands can arise when they are well separated, up to many arise when they are well separated, up to many hundred km.hundred km.

Sharing constraints limit pfd from earth stations Sharing constraints limit pfd from earth stations towards local horizon in shared bands, unless the towards local horizon in shared bands, unless the horizon has an angle of elevation >5º relative to horizon has an angle of elevation >5º relative to the horizontal plane; & boresight angle of the horizontal plane; & boresight angle of elevation >3º,elevation >3º,

Frequency coordination procedures assess Frequency coordination procedures assess probability of interference before entry into service, probability of interference before entry into service, controlling international interference between controlling international interference between stations of the two services through the MIFR.stations of the two services through the MIFR.

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Modes 3 and 4: Frequency Modes 3 and 4: Frequency coordinationcoordination

Many countries use FSS for domestic Many countries use FSS for domestic communication, with earth stations in or near to communication, with earth stations in or near to towns. Some FSS networks have large numbers of towns. Some FSS networks have large numbers of small-antenna earth stations, many in city centres. small-antenna earth stations, many in city centres. Thus the original concept of sharing between the Thus the original concept of sharing between the FS and the FSS is no longer generally applicable.FS and the FSS is no longer generally applicable.

When few earth stations are required it is usually When few earth stations are required it is usually possible to find sites for earth stations far possible to find sites for earth stations far removed from terrestrial stations, existing and removed from terrestrial stations, existing and planned, or well shielded from them by hills.planned, or well shielded from them by hills.

When large numbers of earth stations are required When large numbers of earth stations are required in or near towns, better to use different frequency in or near towns, better to use different frequency bands in a given geographical area. Or, take bands in a given geographical area. Or, take advantage of natural topographical shielding, etc.advantage of natural topographical shielding, etc.

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Modes 3 and 4: Frequency Modes 3 and 4: Frequency coordinationcoordination

In most cases frequency coordination is necessary.In most cases frequency coordination is necessary.1.1. Resolution of potential interference problem within Resolution of potential interference problem within jurisdiction of own national frequency authority.jurisdiction of own national frequency authority.2.2. Publication of information on potential Publication of information on potential

international international interference to or from the earth station.interference to or from the earth station.3.3. Foreign national authorities identify terrestrial Foreign national authorities identify terrestrial

stations at risk, prospective interference levels are stations at risk, prospective interference levels are calculated & problems are resolved.calculated & problems are resolved.

4.4. BR notified of coordinated frequency assignments BR notified of coordinated frequency assignments to earth station & terrestrial stations & registers to earth station & terrestrial stations & registers them in the MIFR.them in the MIFR.

5.5. Changes to assignments which increase risk of Changes to assignments which increase risk of interference are re-coordinated, & new FS interference are re-coordinated, & new FS

assignments are notified to BR for technical assignments are notified to BR for technical examinationexamination

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Coordination – Stage 1 NationalCoordination – Stage 1 National

When location & frequency assignments When location & frequency assignments provisionally provisionally

selected for earth station, national terrestrial selected for earth station, national terrestrial stations which might cause or suffer significant stations which might cause or suffer significant interference are identified.interference are identified. Calculate predicted interference level in each case.Calculate predicted interference level in each case. Determine acceptable level of interference in Determine acceptable level of interference in channels of terrestrial systems from earth station channels of terrestrial systems from earth station & vice-versa.& vice-versa. Decide what part of limit of interference Decide what part of limit of interference recommended for the HRC can safely be allotted to recommended for the HRC can safely be allotted to interference from the earth station to the interference from the earth station to the terrestrial station and vice-versa.terrestrial station and vice-versa.

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Coordination – Stage 1 NationalCoordination – Stage 1 National

If interference is unacceptably high, consider If interference is unacceptably high, consider whether the criteria may be relaxed.whether the criteria may be relaxed.

In general find ways to reduce interferenceIn general find ways to reduce interference

- - Rearrange frequency assignmentsRearrange frequency assignments

- Reduce transmitter powerReduce transmitter power- Reduce sidelobe gainReduce sidelobe gain- Re-site terrestrial radio relay stations or Re-site terrestrial radio relay stations or the the

earth stationearth station

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Coordination - Stage 2Coordination - Stage 2 Authority A prepares maps of area around earth Authority A prepares maps of area around earth station (the coordination area) where, pessimistically, station (the coordination area) where, pessimistically, interference to or from terrestrial station could be interference to or from terrestrial station could be significant.significant. If this area encloses parts of any foreign countries, If this area encloses parts of any foreign countries, authorities B1, or B2, etc., A sends copy of maps & all authorities B1, or B2, etc., A sends copy of maps & all relevant information to each of those authorities & to relevant information to each of those authorities & to ITU/BRITU/BR

necessary to apply pessimistic approximations in necessary to apply pessimistic approximations in compiling RR Appendix 7 to be sure that no potential compiling RR Appendix 7 to be sure that no potential

interference risk is overlooked.interference risk is overlooked. Thus, most stations which are identified as possible Thus, most stations which are identified as possible sources of or sufferers from interference will be sources of or sufferers from interference will be found to have negligible interference potential.found to have negligible interference potential.

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Coordination – Stage 3Coordination – Stage 3

B1, B2, etc. make preliminary examination of B1, B2, etc. make preliminary examination of probability that their terrestrial stations within the probability that their terrestrial stations within the coordination areas will cause or suffer significant coordination areas will cause or suffer significant interference. B gives A all relevant information on interference. B gives A all relevant information on stations which may need detailed study. stations which may need detailed study.

If necessary, A will meet each B authority to If necessary, A will meet each B authority to calculatecalculate

what the interference levels will be. what the interference levels will be. If significant interference is foreseen, use same If significant interference is foreseen, use same processes, etc as in Stage 1. processes, etc as in Stage 1. When all potential interference problems have been When all potential interference problems have been solved, coordination is complete.solved, coordination is complete.

58BAL


A notifies BR of coordinated earth station A notifies BR of coordinated earth station assignmentsassignments

B notifies BR of their coordinated terrestrial stations B notifies BR of their coordinated terrestrial stations

These assignments are registered in the MIFR. The These assignments are registered in the MIFR. The regulations protect:regulations protect:- The interests of authority A if a B authority is The interests of authority A if a B authority is

unwilling to coordinate,unwilling to coordinate,- The interests of a B authority if is unable to The interests of a B authority if is unable to

coordinate andcoordinate and- The interests of any other authority that should The interests of any other authority that should

have been brought into the process of coordination, have been brought into the process of coordination, but was notbut was not

59BAL

Provision for ‘Multilateral Planning Provision for ‘Multilateral Planning Meetings’ (MPM)Meetings’ (MPM)

Parallel operation to coordinate the operation of Parallel operation to coordinate the operation of the earth stations with terrestrial stations the earth stations with terrestrial stations

When agreement is reached in coordination with When agreement is reached in coordination with all the B Administrations with a right to be all the B Administrations with a right to be involved, Administration A submits the agreed involved, Administration A submits the agreed frequency assignments to the BR for registration. frequency assignments to the BR for registration.

BR will check that the consent of all parties with a BR will check that the consent of all parties with a right to be consulted has been obtained, and will right to be consulted has been obtained, and will then register the details.then register the details.

60BAL


Coordination has to be repeated if changes are Coordination has to be repeated if changes are made.made.

If a new uncoordinated terrestrial assignment is If a new uncoordinated terrestrial assignment is

proposed, the assignment is notified to the BR, and proposed, the assignment is notified to the BR, and

subjected to a technical assessment, before it is subjected to a technical assessment, before it is

registered in the MIFRregistered in the MIFR

61BAL

Stage 2 method – App 7Stage 2 method – App 7

concerned with potential interferenceconcerned with potential interference

Two stage processTwo stage process- determination of coordination distance- determination of coordination distance- detailed evaluation- detailed evaluation

COORDINATION for an earth stationCOORDINATION for an earth station- min. coordination distance 100kmmin. coordination distance 100km- two modes:two modes:

- - clear air: diffraction, refraction, ducting (confined clear air: diffraction, refraction, ducting (confined

to great circle path)to great circle path) - hydro meteor scatter (may not be great circle)- hydro meteor scatter (may not be great circle)

63BAL

Appendix 7 Procedure Appendix 7 Procedure

64BAL

Appendix 7 Procedure (2)Appendix 7 Procedure (2)

66BAL

Network coordinationNetwork coordination

Regulatory methods to limit interference between Regulatory methods to limit interference between

geostationary satellite networksgeostationary satellite networks

- equipment performance standards and equipment performance standards and constraints constraints

on system parameterson system parameters- max level is set for interference from 1 satellite max level is set for interference from 1 satellite

network to another; this is called the maximum network to another; this is called the maximum single entry value of permissible interferencesingle entry value of permissible interference

-- any network permits this amount of any network permits this amount of interference to enter any channel of his interference to enter any channel of his network from any other networknetwork from any other network

68BAL

When full technical details available,When full technical details available, - Admin A notifies the details- Admin A notifies the details - draws up a list of other networks with - draws up a list of other networks with which coordination is requiredwhich coordination is required - sends a copy of details of new network to the - sends a copy of details of new network to the administrationsadministrations

BR publishes the details and the list in the circularBR publishes the details and the list in the circular

The right of a network to coordinate:The right of a network to coordinate:- other network is already either registered in MIFR other network is already either registered in MIFR or it has begun the process of coordinationor it has begun the process of coordination- other network is in conformity with RRother network is in conformity with RR- increase in increase in T/T is more than 6%.T/T is more than 6%.

69BAL

If no other networks qualify for coordination:If no other networks qualify for coordination:Admin A asks BR to register assignmentsAdmin A asks BR to register assignments

Usually, coordination is necessaryUsually, coordination is necessaryAdmin A meets privately and separately with each Admin A meets privately and separately with each

of the B Administrationsof the B Administrations- change shape of coverage area of satellite - change shape of coverage area of satellite beams beams

or improve sidelobe performance of antennas,or improve sidelobe performance of antennas, - improve earth station sidelobe performance,- improve earth station sidelobe performance, - reduce satellite down-link power by increasing - reduce satellite down-link power by increasing earth station antenna diameter,earth station antenna diameter, - change carrier frequency of the emissions so - change carrier frequency of the emissions so that high levels of emission density do not fall that high levels of emission density do not fall into the pass-band of sensitive demodulators,into the pass-band of sensitive demodulators, - change orbital location of one of the satellites,- change orbital location of one of the satellites,

70BAL

Coordination of satellite networks Coordination of satellite networks and registration of assignmentsand registration of assignments

estimates of prospective interference levels estimates of prospective interference levels likely likely

to be very approximate,to be very approximate, estimates are likely to be pessimistic, to ensure estimates are likely to be pessimistic, to ensure

that that

no risk of a significant problem is overlookedno risk of a significant problem is overlooked

- not a suitable basis for a definitive - not a suitable basis for a definitive coordination coordination

processprocess

71BAL

Appendix 8 of the Radio Appendix 8 of the Radio RegulationsRegulations

to determine if coordination is required between to determine if coordination is required between

geostationary satellite networks sharing the same geostationary satellite networks sharing the same

frequency bands, where wanted and interfering frequency bands, where wanted and interfering

networks share one of more frequency bands,networks share one of more frequency bands,

- - case 1: each in the same direction of transmissioncase 1: each in the same direction of transmission

- case 2: each in opposite directions of transmission - case 2: each in opposite directions of transmission

(bi-directional use).(bi-directional use).

For both:For both:

- simple frequency changing transponders,- simple frequency changing transponders,

- signal processing transponders- signal processing transponders

72BAL

Satellite antenna spilloverSatellite antenna spillover

Satellite beam may be misdirectedSatellite beam may be misdirected

- Beams to be pointed with tolerance of 10% of - Beams to be pointed with tolerance of 10% of the half-power beamwidth or 0.3ºthe half-power beamwidth or 0.3º

- too much satellite antenna gain outside service - too much satellite antenna gain outside service areaarea

- susceptibility to interference & liability to - susceptibility to interference & liability to cause itcause it

- emissions with highly non-uniform distribution - emissions with highly non-uniform distribution of energy across their spectrum liable to cause of energy across their spectrum liable to cause a disproportionately high level of interference.a disproportionately high level of interference.

- energy dispersal of an FM carrier- energy dispersal of an FM carrier

- addition of a pseudo-random digital - addition of a pseudo-random digital sequencesequence

74BAL

Advance Publication of a new Advance Publication of a new satellite networksatellite network

All proposed new planned date of bringing into All proposed new planned date of bringing into service.service.

Notifying administration (A) will not usually Notifying administration (A) will not usually provide full details of the planned network at this provide full details of the planned network at this stagestage

Includes:Includes: - proposed satellite orbital location;- proposed satellite orbital location; - coverage area(s) of its beam(s)- coverage area(s) of its beam(s) - receiving sensitivity;- receiving sensitivity; - transmitted spectral power density of its - transmitted spectral power density of its transponderstransponders

BR publishes this information to all BR publishes this information to all administrations in its fortnightly circular.administrations in its fortnightly circular.

75BAL

Advance PublicationAdvance Publication

Proposed new satellite networks notified by Proposed new satellite networks notified by

Admin. A to BR as soon as possible, but not Admin. A to BR as soon as possible, but not more more

than 5 years before the planned date of bringing than 5 years before the planned date of bringing

into service. (all networks – GSO or not).into service. (all networks – GSO or not).

76BAL

Some Key Issues…Some Key Issues…

““Paper” satellitesPaper” satellites Over-filingOver-filing ITU backlogITU backlog Due diligenceDue diligence Financial requirementsFinancial requirements Reform of the ITU processReform of the ITU process Possible “implosion” of the satellite coordination Possible “implosion” of the satellite coordination

processprocess

77BAL

““Paper” SatellitesPaper” Satellites

Until the end of the 1980’s, almost all filings were Until the end of the 1980’s, almost all filings were made made afterafter the design and planning of the the design and planning of the satellite satellite

At the start of the 1990s Tonga began filing for At the start of the 1990s Tonga began filing for orbital filings without specific projectsorbital filings without specific projectsSee See http://www.mendosa.com/tongasat.htmlhttp://www.mendosa.com/tongasat.html

This was the start of the revolution in filing that This was the start of the revolution in filing that has significantly altered the ITU processhas significantly altered the ITU process

Now many administrations file for many more Now many administrations file for many more slots than they will or can ever useslots than they will or can ever use

78BAL

Over-FilingOver-Filing

The increase in “paper” satellites has led to a The increase in “paper” satellites has led to a massive over-filing in the ITU processmassive over-filing in the ITU process Most of these filings will never be implemented Most of these filings will never be implemented

(they are technically incompatible!)(they are technically incompatible!) Electronic filing has only made things worseElectronic filing has only made things worse

It is now very easy to make several hundred It is now very easy to make several hundred filings at a single time, if this is desired!filings at a single time, if this is desired!

The ITU has no ability or mandate to “judge” if a The ITU has no ability or mandate to “judge” if a filing is seriousfiling is serious All filings must be processed by the ITU and All filings must be processed by the ITU and

coordinated by administrationscoordinated by administrations This is imposing a serious burden on all This is imposing a serious burden on all

concernedconcerned

79BAL

ITU BacklogITU Backlog

A key effect of over-filing is a significant increase A key effect of over-filing is a significant increase in the ITU backlogin the ITU backlog

10 years ago the time from ITU receipt to 10 years ago the time from ITU receipt to publication was 4 to 6 monthspublication was 4 to 6 months

Today it is 2 to 3 years!Today it is 2 to 3 years! The time for completion of coordination has been The time for completion of coordination has been reducedreduced

Before 1997 it was effectively 9 yearsBefore 1997 it was effectively 9 years Now it is 5 years with a limited 2 year extensionNow it is 5 years with a limited 2 year extension

Thus it is now almost impossible to complete Thus it is now almost impossible to complete coordination within the time limitscoordination within the time limits

This is a serious burden on administrations and This is a serious burden on administrations and operators that are planning real networksoperators that are planning real networks

80BAL

Due DiligenceDue Diligence

To try and improve the situation, WRC-97 adopted To try and improve the situation, WRC-97 adopted an an

“ “Administrative Due Diligence” procedureAdministrative Due Diligence” procedureInformation about the manufacture and launch Information about the manufacture and launch

contracts must be provided for all networks contracts must be provided for all networks withinwithin

the regulatory time limitthe regulatory time limit BUT this is having little impact on the situationBUT this is having little impact on the situation

The information is very generalThe information is very generalThe ITU has no policing functionThe ITU has no policing functionMany (most?/all?) administrations are supplying Many (most?/all?) administrations are supplying

this data “creatively”this data “creatively”

81BAL

Financial RequirementsFinancial Requirements

Some administrations have been suggesting that Some administrations have been suggesting that

deposits and fees should be payable to make deposits and fees should be payable to make

satellite filingssatellite filingse.g. US$ 1M to make a filing, returnable e.g. US$ 1M to make a filing, returnable ifif the the

network is launchednetwork is launched This has not found acceptable in the ITU This has not found acceptable in the ITU

membership as it is seen as penalising the poor membership as it is seen as penalising the poor and and

small countriessmall countries “ “Cost recovery” of processing and publication has Cost recovery” of processing and publication has

been adoptedbeen adopted However… none of this impacts the backlog!However… none of this impacts the backlog!

82BAL

Reform of the ITU ProcessReform of the ITU Process

Some attempts have been made to reform the Some attempts have been made to reform the ITU ITU

process and deal with the backlogprocess and deal with the backlog BUT there is no consensus in the ITU as to how BUT there is no consensus in the ITU as to how

this this

should be done!should be done!

- How to be fair to all administrations?- How to be fair to all administrations?- How to change things without penalising the How to change things without penalising the

networks in the backlog?networks in the backlog?

- How to stop the massive over-filing?- How to stop the massive over-filing?

83BAL

Possible “implosion” of the satellite Possible “implosion” of the satellite coordination processcoordination process

Clearly the system cannot go on as it is!Clearly the system cannot go on as it is! The backlog is increasing, not diminishingThe backlog is increasing, not diminishing Soon the coordination requests will be Soon the coordination requests will be published published

after the networks have expired!after the networks have expired! ITU addressed this at Plenipotentiary ITU addressed this at Plenipotentiary Conference in Conference in

2002 and atWRC-20032002 and atWRC-2003

84BAL

The Physical Problem…The Physical Problem…

Physical Occupancy of the GSO - August 2002(289 satellites!)

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85BAL

The Paper Problem…The Paper Problem…

"Filing" Occupancy of the GSO - August 2002(3084 distinct network filings - last year 2355!)

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86BAL

The Paper Problem…The Paper Problem…

Filings vs. real networks

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87BAL

Non-Geostationary Satellite Non-Geostationary Satellite NetworksNetworks

- Many proposals for non-GSO satellite networks.- Many proposals for non-GSO satellite networks.- Advantages:- Advantages:

- path loss is smaller- path loss is smaller- time delay on the path is smaller- time delay on the path is smaller- non-GSO systems can reduce the crowding in non-GSO systems can reduce the crowding in

GSOGSO

- Disadvantages:Disadvantages:- network providing a service will require a - network providing a service will require a

constellation of satellitesconstellation of satellites- changing geometry would require tracking - changing geometry would require tracking

antennas or low gain omnidirectional antennasantennas or low gain omnidirectional antennas- traffic switching between satellites and probably - traffic switching between satellites and probably

signal processing.signal processing.

88BAL

Non-Geostationary Satellite Non-Geostationary Satellite NetworksNetworks

Teledesic Teledesic -- FSS 20/30 GHzFSS 20/30 GHz

IridiumIridium -- MSS 2 GHzMSS 2 GHz

89BAL

NGSO Emission limitsNGSO Emission limits There are differing requirements in the various There are differing requirements in the various

frequency bands which provide limits for frequency bands which provide limits for interference from non-GSO space stations into the interference from non-GSO space stations into the GSO. For example:GSO. For example:

22.5A In the frequency band 6 700-7 075 MHz, 22.5A In the frequency band 6 700-7 075 MHz, the maximum aggregate power flux-density the maximum aggregate power flux-density produced at the geostationary-satellite orbit and produced at the geostationary-satellite orbit and within ±5º of inclination around the geostationary-within ±5º of inclination around the geostationary-satellite orbit by a non-geostationary-satellite satellite orbit by a non-geostationary-satellite system in the fixed-satellite service shall not system in the fixed-satellite service shall not exceed –168 dB(W/m²) in any 4 kHz band.exceed –168 dB(W/m²) in any 4 kHz band.

Interference at the earth’s surface from non-GSO Interference at the earth’s surface from non-GSO limited by specifying the equivalent power flux limited by specifying the equivalent power flux density (epfd)density (epfd)

bal 1 the radio spectrum: utilisation and management part 2 les barclay

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