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Determinations/Communications as made
This instrument sets out what is an unacceptable level of interference caused by a radiocommunications transmitter operating under a spectrum licence issued in the frequency band 2570-2620 MHz (the 2.5 GHz Mid-band Gap).
Administered by: Communications and the Arts
General Comments: This Determination commences on the same day as the Radiocommunications Spectrum Conversion Plan (2.5 GHz Mid-band Gap) 2012.
Made 13 Dec 2012
Registered 20 Dec 2012
Tabled HR 05 Feb 2013
Tabled Senate 05 Feb 2013

The AUSTRALIAN COMMUNICATIONS AND MEDIA AUTHORITY makes this Determination under subsection 145 (4) of the Radiocommunications Act 1992.

Dated 13th December 2012

Chris Chapman
[signed]
Member

 

Richard Bean
[signed]
 Member/General Manager

1          Name of Determination

                This Determination is the Radiocommunications (Unacceptable Levels of Interference – 2.5 GHz Mid-band Gap) Determination 2012.

2          Commencement

This Determination commences on the same day as the Radiocommunications Spectrum Conversion Plan (2.5 GHz Mid-band Gap) 2012.

Note All legislative instruments and compilations are registered on the Federal Register of Legislative Instruments kept under the Legislative Instruments Act 2003. See http://www.frli.gov.au

 

3          Purpose

                This Determination is made for the purposes of section 145 of the Act and sets out what is an unacceptable level of interference caused by a radiocommunications transmitter operating under a spectrum licence issued in the 2.5 GHz Mid-band Gap, so as to ensure that high levels of emission from radiocommunications transmitters operated under a spectrum licence are kept within the geographic area and frequency band of the licence.

Note 1    Under section 145 of the Act, the ACMA may refuse to register a radiocommunications transmitter if it is satisfied that the operation of the radiocommunications transmitter could cause an unacceptable level of interference to the operation of other radiocommunications devices under that or any other spectrum licence, or any other licence.  

Note 2    The ACMA information paper, Registration of radiocommunications devices under spectrum licences, (available on the ACMA website: www.acma.gov.au), provides further information about the registration of radiocommunications transmitters under Part 3.5 of the Act.

Note 3    The ACMA has issued written advisory guidelines under section 262 of the Act about compatibility requirements in relation to the assignment of frequencies to radiocommunications transmitters operated under apparatus licences and the operation of radiocommunications transmitters under spectrum licences. The ACMA may take these guidelines into account during the settlement of interference disputes. Each case will be assessed on its merits. The guidelines do not prevent a licensee negotiating other compatibility requirements with another licensee. The guidelines are:

·  Radiocommunications Advisory Guidelines (Managing Interference from Transmitters — 2.5 GHz Mid-band Gap) 2012; and

·  Radiocommunications Advisory Guidelines (Managing Interference to Receivers — 2.5 GHz Mid-band Gap) 2012.

These instruments can be accessed on the ComLaw website: www.comlaw.gov.au.

4          Interpretation

(1)       In this Determination, unless the contrary intention appears:

2.5 GHz Mid-band Gap means the frequency band 2570 MHz – 2620 MHz.

Act means the Radiocommunications Act 1992.

Australian Spectrum Map Grid (ASMG) means the Australian Spectrum Map Grid 2012 published by the ACMA, as in force from time to time.

Note       The ASMG can be accessed on the ACMA website: www.acma.gov.au.

centre frequency, in relation to a radiocommunications transmitter, means the frequency midway between the lower and upper frequency limits of the transmitter’s effective occupied bandwidth.

DEM-9S means the “GEODATA 9 Second Digital Elevation Model (DEM-9S) Version 3” (Australia New Zealand Land Information Council identifier: ANZCW0703011541) containing modelled terrain height information for Australia, published by Geoscience Australia, as in force from time to time.

Note        Copies of the DEM-9S can be obtained from Geoscience Australia: www.ga.gov.au.

DEM-9S cell means an individual height element of the DEM-9S.

device boundary, in relation to a radiocommunications transmitter or a group of radiocommunications transmitters operated under a spectrum licence, means the device boundary established in accordance with Part 1 of Schedule 2.

device boundary criterion means the value of the mathematical expression calculated in accordance with Part 2 of Schedule 2.

effective antenna height means the effective height of an antenna calculated in accordance with Schedule 3.

EIRP, in relation to a radiocommunications device, means the Effective Isotropic Radiated Power of the device.

emission designator means the designation of a radiocommunications transmitter’s emission, determined in accordance with section 5.

fixed receiver means a radiocommunications receiver located at a fixed point on land or sea and not designed or intended for use while in motion.

fixed transmitter means a radiocommunications transmitter located at a fixed point on land or sea and not designed or intended for use while in motion.

Geocentric Datum of Australia 1994 means the geodetic datum designated as the “Geocentric Datum of Australia (GDA94)” gazetted in the Commonwealth of Australia Gazette No. GN 35 on 6 September 1995.

Note       The Geocentric Datum of Australia 1994 is a coordinate reference system which replaces the Australian Geodetic Datum. More information on the GDA94 can be obtained from Geoscience Australia: www.ga.gov.au.   

geographic area, for a spectrum licence, means the area within which operation of a radiocommunications device is authorised under the licence.

group of radiocommunications receivers has the meaning given by section 7.

group of radiocommunications transmitters has the meaning given by section 6.

horizontally radiated power, for a radiocommunications device, means the sum of:

(a)    the maximum true mean power, in dBm per specified rectangular bandwidth at the antenna connector that is located within the frequency band of the spectrum licence authorising the operation of the radiocommunications device; and

(b)   the antenna gain relative to an isotropic antenna in a specified direction in the horizontal plane containing the phase centre of the antenna used with the device, in dBi.

ITU means the International Telecommunication Union.

location in relation to a radiocommunications transmitter, or group of radiocommunications transmitters, means the location of the transmitter or group of radiocommunications transmitters, as the case may be, calculated in accordance with Schedule 1.

maximum true mean power means the true mean power measured in a specified rectangular bandwidth that is located within a specified frequency band such that the true mean power is the maximum of true mean powers produced.

Note        The power within a specified rectangular bandwidth is normally established by taking measurements using either an adjacent channel power meter or a spectrum analyser.  The accuracy of measuring equipment, measurement procedure and any corrections to measurements necessary to take account of practical filter shape factors would normally be in accordance with good engineering practice.

mean power means the average power measured during an interval of time that is at least 10 times the period of the lowest modulation frequency.

occupied bandwidth, in relation to a radiocommunications transmitter, means the width of a frequency band having upper and lower limits that are necessary to contain 99% of the true mean power of the transmitter’s emission at any time.

Radio Regulations means the ‘Radio Regulations’ published by the ITU, as in force from time to time.

Note        Copies of the Radio Regulations can be obtained from the ITU: www.itu.int.

            Recommendation P.526-11 means the ITU Radiocommunications Sector Recommendation P.526-11 “Propagation by Diffraction”, published by the ITU, as in force from time to time.

Note        Recommendation P.526-11 can be accessed through the ITU website at: www.itu.int.

true mean power means:

(a)    if an unmodulated carrier is present — the mean power measured while the unmodulated carrier is present; and

(b)   if an unmodulated carrier is not present — the mean power measured while transmitted information is present.

(2)        In this Determination, unless otherwise specified, the range of numbers that identifies a frequency band includes the higher, but not the lower, number.

Note   A number of terms used in this Determination are defined in the Act and, unless the contrary intention appears, have the meaning given to them by the Act. Those terms include:

·           ACMA

·           core condition

·           frequency band

·           interference

·           radiocommunications device

·           radiocommunications receiver

·           radiocommunications transmitter

·           radio emission

·           Register

·           spectrum licence.

5              Emission designator

(1)            In this Determination, the designation of a radiocommunications transmitter’s emission (emission designator) is determined using the methods specified in the Radio Regulations.

(2)            For the purpose of determining the designation of a radiocommunications transmitter’s emission using the methods specified in the Radio Regulations, the references to necessary bandwidth for a given class of emission are taken to be references to the occupied bandwidth of the transmitter.

Note  At the date of making this Determination, Appendix 1 of the Radio Regulations made provision for determining the designation of a radiocommunications transmitter’s emission.

 

6              Group of radiocommunications transmitters

(1)            In this Determination, two or more fixed transmitters are a group of radiocommunications transmitters if:

                 (a)   they have the same centre frequency and emission designator;

                 (b)   they are operated for the purpose of communicating with the same radiocommunications receiver or group of radiocommunications receivers;

                 (c)   each has an antenna of the same type, model and manufacturer;

                 (d)   the antenna used with each fixed transmitter is located on the same structure and within 20 metres of the phase centre of all antennas within the group of radiocommunications transmitters; and

                 (e)   the identification number assigned by the ACMA to the antenna used with each radiocommunications transmitter is the same.

(2)            A radiocommunications transmitter must not belong to more than one group of radiocommunications transmitters.

(3)            The location of a group of radiocommunications transmitters is calculated in accordance with Schedule 1.

7              Group of radiocommunications receivers

(1)            In this Determination, two or more fixed receivers are a group of radiocommunications receivers if:

                 (a)   they are operated for the purpose of communicating with the same radiocommunications transmitter or group of radiocommunications transmitters;

                 (b)   each has an antenna of the same type, model and manufacturer;

                 (c)   the antenna used with each fixed receiver is located on the same structure and within 20 metres of the phase centre of all antennas within the group of radiocommunications receivers; and

                 (d)   the identification number assigned by the ACMA to the antenna used with each radiocommunications receiver is the same.

(2)            A radiocommunications receiver must not belong to more than one group of radiocommunications receivers.

(3)            The location of a group of radiocommunications receivers is calculated in accordance with Schedule 1 as if the group of radiocommunications receivers were a group of radiocommunications transmitters.

8              Unacceptable level of interference

(1)            A level of interference caused by a radiocommunications transmitter operated under a spectrum licence issued for the 2.5 GHz Mid-band Gap is unacceptable if:

                 (a)   the operation of the transmitter in the 2.5 GHz Mid-band Gap results in a breach of a core condition of the licence relating to the maximum permitted level of radio emission from the transmitter:

                        (i)    outside the part or parts of the spectrum the use of which is authorised under the licence; or

                        (ii)   outside the geographic area of the licence; or

                 (b)   subject to subsection (2) - any part of the device boundary of the transmitter lies outside the geographic area of the licence; or

                 (c)   the device boundary of the transmitter cannot be calculated in accordance with Part 1 of Schedule 2; or

                 (d)   the operation of the transmitter results in emissions above the horizontal plane greater than 43 dBm/30 kHz EIRP.

(2)            A level of interference mentioned in paragraph (1) (b) is not unacceptable in relation to a part of the device boundary that:

(a)  lies outside the boundary of the ASMG; and

(b)  is connected to a radial that:

(i)                              is mentioned in Part 1 of Schedule 2; and

(ii)                            does not cross the geographic area of another licence.

               Note Under subsection 69 (2) of the Act, the ACMA intends to include a licence condition exempting certain radiocommunications transmitters from the requirement to comply with Part 3.5 of the Act.

 

9              Accuracy

       Unless otherwise specified, the value of a parameter in Schedules 1, 2 and 3 must be estimated with a level of confidence not less than 95 percent that the true value of the parameter will always remain below the requirement specified in this Determination.


Schedule 1        Location of a transmitter

(section 4)

1.       The location of a radiocommunications transmitter, (lt, Lt) is the location (by latitude and longitude with reference to the Geocentric Datum of Australia 1994) of the phase centre of the radiocommunications transmitter’s antenna.   

2.       The location of a group of radiocommunications transmitters, (lt, Lt) is the location (by latitude and longitude with reference to the Geocentric Datum of Australia 1994) of the centre point between the phase centre of each radiocommunications transmitter antenna within the group.

3.       In determining the location of a radiocommunications transmitter, or a group of radiocommunications transmitters, the measurement error should be less than 10 metres.     

Note 1       The ACMA issues site identifiers for established radiocommunications transmitter locations available in the Register.

Note 2       The ACMA provides advice on its website to assist licensees in determining the location and measurement error of a transmitter site in the document Business Operating Procedure (BOP) - Radiocommunications site data requirements.


 

Schedule 2        Device boundaries and device boundary criteria

(section 4)

Part 1          Device boundary of a transmitter

1.       The device boundary of a single radiocommunications transmitter is established as follows:

Step 1        Calculate the device boundary criterion at each m × 500 metre increment along each of the n-degree radials, where:

(a)    m is the values 1 through 100; and

(b)   n is the values 0 (true north) through 359.

Step 2        For each radial, find the latitude and longitude of the first point (lowest value of m) where either:

(a)   the device boundary criterion is less than or equal to 0; or

(b)   m is equal to 100.

Step 3        The end point of each radial is the device boundary of the transmitter.

Note 1       It is not necessary to calculate a device boundary for radiocommunications transmitters with a horizontally radiated power less than or equal to 35 dBm/5 MHz as the ACMA does not intend to require these radiocommunications transmitters to be registered (see subsection 69 (2) of the Act and the licence conditions relating to registration of devices under the spectrum licence).

Note 2             The device boundary criterion is calculated under Part 2 of this Schedule.

2.       For a group of radiocommunications transmitters the device boundary is to be calculated as if for a single radiocommunications transmitter. The radiated power (RP) for the group of radiocommunications transmitters is taken:

          (a)     to be equal for each bearing fn; and

          (b)     to have a value that is equal to the maximum horizontally radiated power, in any direction, of any radiocommunications transmitter in the group.

 

Part 2          Device boundary criterion

The device boundary criterion is the value of the mathematical expression:

RP – MP

                       

where:

MP

:

is PL(lmn, Lmn) + LOP - Gr;

 

RP

:

is the horizontally radiated power, in dBm EIRP per 30 kHz, for each bearing, fn ;

 

LOP

:

is the level of protection at the boundary, in dBm per 30 kHz set to -80.4 dBm/30 kHz;

 

Gr

:

is the nominal radiocommunications receiver antenna gain including feeder loss set at 18 dBi;

 

PL(lmn, Lnm)

:

is the propagation loss (dB) set out in Part 3 of the mth increment on the nth radial.

 

 

Part 3         Calculation of propagation loss

 

1.             In calculating PL(lmn, Lnm):

 

f

:

is the centre frequency of the radiocommunications transmitter in megahertz (MHz).

 

hgr

:

is the nominal radiocommunications receiver antenna height above ground level, being 30 metres.

 

hgt

:

is the radiocommunications transmitter antenna height above ground level, in metres, as defined in Schedule 3.

 

hs

:

is the radiocommunications transmitter antenna height above sea level, in metres, as defined in Schedule 3.

 

d(lmn, Lmn)

:

is the distance in metres between the location of the radiocommunications transmitter, (lt, Lt), and the mth increment on the nth radial (lmn, Lmn).

 

:

is the wavelength in metres = (3·108 )/( f ·106).

 

rearth

:

is the effective earth radius in kilometres = 8500.

 

dj

:

are distances in kilometres where the value of j indicates for which increment the distance is being calculated.

 

hagj

:

are average ground heights measured in metres and calculated using the methodology outlined in Schedule 3.

 

2.         The propagation loss PL(lmn, Lnm) between the transmitter at (lt, Lt) and the mth increment on the nth radial (lmn, Lmn) is established by using the following applicable calculations which have been derived from the cascaded knife edge diffraction model specified in section 4.4.2 of Recommendation P.526-11:

 

(a)        Single segment paths

 

For paths with no terrain obstructions as in Diagram 1, the propagation loss is:

 

 

Diagram 1

Path for transmitter at (lt, Lt) to (lmn, Lmn)

(b)        Two segment paths

 

For paths where there is one terrain obstruction as in Diagram 2, the propagation loss is calculated by analysing the path from the location of the transmitter at (lt, Lt) to (lmn, Lmn). The total propagation loss is:

 

 

where

for

for

 

where

and

 

is the positive or negative vertical distance between the top of the obstacle and the straight line joining the two ends of the path.  The distances d1 and d2 are in metres and are the distances to the largest obstacle between (lt, Lt) and (lmn, Lmn).

 

 

Diagram 2

Path for transmitter at (lt, Lt) to (lmn, Lmn)

 

 


 

(c)        Three to thirty segment paths

 

For paths with multiple obstacles as in Diagram 3, calculation of the propagation loss is in three steps over a total of four segments. The propagation loss is:

 

 

where

 

for

for

 

 

 

and J(np ), J(nt ), and J(nr ) are calculated as set out in Steps 1 to 3 below.

 

Diagram 3

Path for transmitter at (lt, Lt) to (lmn, Lmn)

 


 

 

Step 1: Calculate J(np )

 

J(np ) is calculated by analysing the entire path from the location of the transmitter at (lt, Lt) to (lmn, Lmn) as in Diagram 3. The principle diffraction edge (the obstacle with the greatest propagation loss effect) is found by calculating:

over all values of j from 1 to the total number of obstacles, k (= 3 in the example in Diagram 3), where:

with

and

 

J(np ) is then:

for

for

 

Step 2: Calculate J(nt )

 

If , then J(nt ) =0. Otherwise, J(nt ) is calculated by analysing the path from the location of the transmitter to the principle edge, p (see Diagram 4).

 

If p is equal to the value of j for max{νj}, then calculate nt , (the maximum value of nj for limited interval j = 1 to p‑1):

 

in a similar manner as in Step 1.  That is:

 

 

and

 

 


 

Diagram 4

Path for transmitter at (lt, Lt) to point p

 

J(nt ) is then:

 

for

for

 

Step 3: Calculate J(nr)

 

If , then J(nr ) =0. Otherwise, J(nr) is calculated by analysing the path from the principle edge, p, to (lmn, Lmn) (see Diagram 5).

 

The value nr   is then the maximum value of nj for limited range j = p+1 to k:

 

 

calculated in a similar manner as in Step 1.  That is:

 

and

 

Diagram 5

Path for point p to (lmn, Lmn)

 

 

J(nr ) is then:

 

for

for

 

Schedule 3     Effective antenna height and average ground height

(section 4)

Part 1          Effective antenna height of a transmitter

 

1.             If:

(a)           hgt is the vertical height in metres of the phase centre of the fixed transmitter’s antenna measured with an error of less than 5 parts in 100 and relative to the point:

                                        (i)          located on the line of intersection between the external surface of the structure supporting the antenna and the surface of the ground or sea; and

                                       (ii)         having the lowest elevation on that line;

(b)          hs is the sum of the DEM-9S cell height of the location of the radiocommunications transmitter as defined in Schedule 1 and hgt; and

(c)           hagm(fn) is the average ground height of the location at each m-increment on each n-radial as calculated in accordance with Part 2;

then the effective antenna height hem(fn), is hs – hagm(fn) (as shown in Diagram 1) except when hs – hagm(fn) is less than hgt, in which case hem(fn) is hgt.

 

2.             For a group of radiocommunications transmitters, hgt is the greatest of the hgt for each individual transmitter in the group, calculated as in 1(a).

 

3.             If the latitude or longitude of the radiocommunications transmitter as defined in Schedule 1 has a modulus of zero when divided by 0.0025, then hs is the sum of hgt and the maximum height of the adjacent DEM-9S cells.

 

Note           Additional information for the purpose of calculating hs where the latitude or longitude of the radiocommunications transmitter as defined in Schedule 1 corresponds to a DEM-9S cell boundary is provided in the document titled ‘Digital Elevation Model Interpretation’ available on the ACMA website: www.acma.gov.au.


 

 

Diagram 1      Calculating effective antenna height            

 

Part 2          Average ground height

1.             The average ground height for the mth increment on the nth radial is calculated as follows:

 

Step 1:         determine the associated latitude and longitude of the mth increment on the nth radial as calculated in Part 3.

 

Step 2:         identify the DEM-9S cell represented by the latitude and longitude of the mth increment on the nth radial.

 

Step 3:         bound the identified DEM-9S cell with the 8 adjacent DEM-9S cells in a 3x3 matrix and obtain each DEM-9S cell height attribute (as shown in Diagram 2).

 

Step 4:         determine the average value of height from the 3x3 matrix.

 

2.              If the latitude or longitude  of the mth increment on the nth radial as calculated in Part 3 has a modulus of zero when divided by 0.0025, then the corresponding DEM-9S cell as identified in Step 2 above, is the cell with the lowest height of the adjacent DEM-9S cells.

 

Note Additional information for the case where the associated latitude or longitude of the mth increment on the nth radial as calculated in Part 3 corresponds to a DEM-9S cell boundary can be found in the document titled ‘Digital Elevation Model Interpretation’ available on the ACMA website: www.acma.gov.au.


 

 

 

Diagram 2     Calculating average ground height

 

 

 

Part 3          Vincenty’s Formulae

Note     This implementation of Vincenty’s Direct Formulae uses the parameters from the GRS80 ellipsoid as referenced by the Geocentric Datum of Australia 1994 (GDA 94).

 

1.         In calculating:

 

lt

:

is the latitude of the fixed transmitter (decimal degrees)

Lt

:

is the longitude of the fixed transmitter (decimal degrees)

α

:

is the azimuth angle (decimal degrees)

d

:

is the separation distance to required point (m×500 metres)

a

:

is the semi-major axis of GDA94 (6378137m)

fl

:

is the flattening of GDA94 (1/298.25722210)

b

:

is the semi-minor axis of GDA94 (a×(1-fl))


 

 

2.       Using an initial value , iterate the following three equations until the change in is less than 10-12.

         

 

3.       Then: