Frequency Assignment PlanningPrepared by Torsten JacobICAO ANB/CNS

MID Office, Cairo, 4 6 June 2006

General MethodologyThe electromagnetic compatibility of radio equipment should be calculated by the following method:determine the desired signal level at the victim receiver front end;determine the resulting level of interference at the victim receivers front end;determine the interactive effects among wanted signals, interference and receiver characteristics for various frequency or distance separations;determine the appropriate propagation model to be used; anddetermine, from these data, a relationship between the frequency separation and distance separation that the interference is considered tolerable.

MID Office, Cairo, 4 6 June 2006

Free Space Propagation ModelThe propagation loss that would occur if the antennas were replaced by isotropic antennas located in a perfectly dielectric, homogeneous, isotropic and unlimited environment, the distance between the antennas being retained (see Recommendation ITU-R P.525).

MID Office, Cairo, 4 6 June 2006

Aeronautical Standard Propagation Model Aeronautical standard propagation model (ASPM) is derived from the ITU-R Recommendation P.528. For distances up to the radio horizon, free space propagation is assumed. Beyond the radio horizon, a constant attenuation factor a, which depends on the frequency band under consideration, is used.

MID Office, Cairo, 4 6 June 2006

Tx

Rx

k

R

E

h

Rx

h

Tx

d

RH

Radio horizonIf both heights hTX and hRX are expressed in feet (ft), the distance d in Nautical Miles (NM), the Earth radius RE=6360km and if the atmospheric conditions are assumed to be normal (effective Earth radius factor k=4/3), the following practical formula can be used to calculate the radio horizon:

MID Office, Cairo, 4 6 June 2006

Aeronautical Standard Propagation ModelThe propagation loss in dB between two isotropic antennas located in a perfectly dielectric, homogeneous, isotropic and unlimited environment can be calculated as follows:

MID Office, Cairo, 4 6 June 2006

VHF COMGeneral principles for VHF voice communication:To protect a service with a circular operational coverage (circular service), the distances from the edge of the service to another airborne or ground transmitter must be 5 times the range of that circular service; if the other transmitter is below the radio horizon from that service edge and the radio horizon distance is also less than 5 times circular service range then radio horizon distance is to be used;

MID Office, Cairo, 4 6 June 2006

VHF COMGeneral principles for VHF voice communication:To protect a service with a non-circular operational coverage area the ground or airborne transmitter of the other service must be below the radio horizon;the protection criteria for both the requested service and the existing assignment must be met for a valid assignment.

MID Office, Cairo, 4 6 June 2006

VHF COM

MID Office, Cairo, 4 6 June 2006

AFIS

TWR 16/FL30

TWR

25/FL40

APP

25/FL100

APP

40/FL150

ATIS

60/FL200

APP

50/FL250

VOLMET

261/FL450

ACC

FL150

ACC

FL245

ACC

FL350

ACC

FL450

AFIS/TWR (16/FL30)

80

125

125

200

241*

250

328*

218*

260*

298*

328*

TWR

25/FL40

125

125

125

200

252*

250

339*

228*

270*

308*

339*

APP

25/FL100

125

125

125

200

297*

250

384*

274*

316*

353*

384*

APP

40/FL150

200

200

200

200

300

250

412*

301*

343*

381*

412*

ATIS

60/FL200

241*

252*

297*

300

114*

300

201*

300

300

300

300

APP

50/FL250

250

250

250

250

300

250

455*

345*

387*

425*

455*

VOLMET

261/450

328*

339

384*

412*

201*

455*

0*

412*

454*

491*

522*

ACC

FL150

218*

228*

274*

301*

300

345*

412*

301*

343*

381*

412*

ACC

FL245

260*

270*

316*

343*

300

387*

454*

343*

385*

423*

454*

ACC

FL350

298*

308*

353*

381*

300

425*

491*

381*

423*

460*

491*

ACC

FL450

328*

339*

384*

412*

300

455*

522*

412*

454*

491*

522*

ILSCo-channel protection requirement for ILS localizerMinimum separation between undesired facility (ILS2) and the Protection Point of the desired facility (ILS1) of 80 NM80 NMILS localizer protection point at 25 NM distance and6250 ft heightMinimum separation between second facilityand the protection point of the first facilityILS 1ILS 2UNDESIRED SIGNAL

MID Office, Cairo, 4 6 June 2006

VORUNDESIRED SIGNALVOR 2INTERFERENCE SOURCEVOR 1Co-channel protection requirementMinimum uplink free-space desired-to-undesired signal ratio (D/U) of 20 dB at all points within the desired facilitys service volume

MID Office, Cairo, 4 6 June 2006

DMEDME 2INTERFERENCE SOURCE(S)DME 1Ground facilities channel assignment:Minimum uplink free-space desired-to-undesired signal ratio (D/U) at all points within the desired facilitys service volumeSpecific free-space D/U values are selected in order to guarantee an effective post-processing D/U of 8 dB taking into account frequency and code rejection capabilities of the interrogator receiver

MID Office, Cairo, 4 6 June 2006

More informationMore information on assignment planning principles for systems such as NDB, GBAS, HF voice and data, VDL Mode 2, 3 and 4 etc can be found at:ICAO Annex 10ICAO RF Handbook Doc 9718Publications of ICAO Regional Offices such asFMG Frequency Management ManualNational regulations on aeronautical assignment planning

MID Office, Cairo, 4 6 June 2006

Thank YouAny questions?

MID Office, Cairo, 4 6 June 2006