ATTACHMENT H
EXPLANATORY STATEMENT
Radiocommunications (Unacceptable Levels of Interference — 2010–2025 MHz Band) Determination 2006
Made by the Authority of the Australian Communications and Media Authority under sections 69 and 145 of the Radiocommunications Act 1992
Legislative Provisions
Under subsection 145 (4) of the Radiocommunications Act 1992 (the Act) the Australian Communications and Media Authority (ACMA) may determine what are unacceptable levels of interference for the purposes of deciding whether to refuse to include in the Register of Radiocommunications Licences (Register) a transmitter that is proposed to be operated under a spectrum licence.
Section 69 of the Act requires each spectrum licence to include a condition which specifies that a radiocommunications transmitter must not be operated under the licence unless the requirements of ACMA under Part 3.5 of the Act for registration of transmitters have been met. Section 69 also provides that the condition may exempt radiocommunications transmitters of particular kinds from having to meet those registration requirements.
Purpose
The Radiocommunications (Unacceptable Levels of Interference – 2010-2025 MHz Band) Determination 2006 (the Determination) sets out what is an unacceptable level of interference caused by a transmitter operating under a spectrum licence issued in the 2010‑2025 MHz band. This enables licensees to ensure that emissions from transmitters operated under their licence are kept within the geographic area and frequency band of the licence and consequently determine whether they meet ACMA requirements for inclusion in the Register.
Background
In Australia there has been growing interest in the potential of wireless broadband technologies to deliver a range of services. Demand for higher speed internet access is one of the key drivers. Broadband wireless access (BWA) can provide higher data rates over greater distances and may be deployed more rapidly than current copper cable (DSL) technologies.
In response to this demand, on 4 April 2005, the Minister for Communications, Information Technology and the Arts declared the 2010–2025 MHz band in designated areas of Australia subject to re‑allocation under section 153B of the Act by issuing spectrum licences. The designated areas are defined in the Minister’s Radiocommunications (Spectrum Re‑allocation) Declaration No.1 of 2005 (the Re-allocation Declaration).
When the Minister’s Re-allocation Declaration was made, the 2010–2025 MHz band was principally used for high speed point-to-point data transmission by a major telecommunications carrier. The seven incumbents (with 24 assignments) hold apparatus licences and have been aware of the possible change to the spectrum’s designation since 2000.
In April 2006 the Minister amended the Re-allocation Declaration to change the New South Wales / Australian Capital Territory and South Queensland boundary slightly. In addition, the re-allocation deadline and re-allocation period were extended. ACMA wrote to all incumbents in May 2006 to inform them that the Minister had extended the re-allocation period to 31 December 2007.
The re-allocation is intended to enable the further expansion of BWA services by telecommunications providers in metropolitan and regional areas of Australia. This Determination is part of a set of legal instruments to give effect to the re-allocation of spectrum identified in the Re-allocation Declaration. The complete set of instruments required for this purpose is listed below:
● Radiocommunications (Spectrum Re‑allocation) Declaration No.1 of 2005 (as amended);
● Radiocommunications Spectrum Marketing Plan (2010–2025 MHz Band) 2006;
● Radiocommunications (Spectrum Licence Allocation — 2010–2025 MHz Band) Determination 2006;
● Radiocommunications (Unacceptable Levels of Interference — 2010–2025 MHz Band) Determination 2006;
● Radiocommunications Advisory Guidelines (Managing Out-of-Band Interference from Frequency Adjacent Transmitters in Spectrum Licensed Receivers — 2010–2025 MHz Band) 2006; and
● Radiocommunications Advisory Guidelines (Protection of Apparatus licensed and Class licensed Receivers — 2010–2025 MHz Band) 2006.
Consultation
Under the Re-allocation Declaration, the Radiocommunications Spectrum Marketing Plan (2010–2025 MHz Band) 2006 (the Marketing Plan) is the instrument in the package that sets out matters a licensee must take into account in operating devices under a 2010-2025 MHz band spectrum licence. The Marketing Plan provides the core conditions for a spectrum licence in this band and sets emission limits for outside the spectrum licensed frequency band and geographic area. ACMA consulted publicly on the draft Marketing Plan and did not receive any objections to the core conditions or emission limits.
In May 2005, ACMA formed a joint technical liaison group (TLG) with industry to assist in developing the technical framework for spectrum licensing in the 2010‑2025 MHz band. Membership of the TLG was open to any interested party. The work of this consultative group reached consensus on the framework and was completed in June 2006 after consideration of four discussion papers prepared by ACMA and two drafts of this Determination, the two radiocommunications advisory guidelines listed in the Background and the conditions to be included in a 2010‑2025 MHz band spectrum licence (as shown in the sample licence in Schedule 4 of the Marketing Plan).
The Office of Regulation Review (ORR) advised that a Regulation Impact Statement (RIS) was not required for the package of instruments that set the arrangements for the auction of the spectrum as listed in the Background. The ORR notes that a RIS was prepared and assessed as adequate by the ORR for the Minister’s decision to re-allocate this part of the spectrum by spectrum licence (ORR ID 7901).
Legal and other requirements
Determinations made under section 145 of the Act are legislative instruments for the purposes of the Legislative Instruments Act 2003. All legal and other requirements for the making of this Determination have been met.
Attachments
Details of the Determination are in Attachment 1.
ATTACHMENT 1
Notes on sections
Section 1 Name of Determination
This section gives the citation for the Determination.
Section 2 Commencement
This section specifies that the Determination takes effect from the day after it is registered.
Section 3 Purpose
This section states the purpose of the Determination, which is to set out the technical rules defining what will be considered unacceptable levels of interference when a licensee applies to ACMA to register transmitter devices for operation in the 2010–2025 MHz band on the Register.
The notes attached to this section explain that although ACMA may refuse to register transmitters considered to cause unacceptable levels of interference, registration is still possible where licensees can demonstrate that sufficient ‘guard space’ has been applied in accordance with ACMA’s Radiocommunications Advisory Guidelines (Registration of Transmitters without an Interference Impact Certificate) 1998 to provide an equivalent level of interference protection as defined in this Determination.
The notes also provide references to other advisory guidelines made by ACMA under section 262 of the Act which will provide a basis for its settlement of any interference disputes that may arise between spectrum licensees and any licensees in adjacent licence areas and bands.
Section 4 Interpretation
This section provides definitions for terms used in the Determination.
Section 5 Group of transmitters
This section defines what is ‘a group of transmitters’ for the purpose of the Determination. A group of transmitters consists of a number (more than one) of fixed transmitters that have the following common features:
● the same emission centre frequency;
● the same emission designated;
● they each operate for the purpose of communicating with the same receiver or group of receivers; and
● the same identification number is assigned to the antenna used with each transmitter.
Section 6 Group of receivers
This section defines what is ‘a group of receivers’ for the purpose of the Determination. A group of receivers consists of a number (more than one) of fixed receivers that have the following common features:
● they each operate for the purpose of communicating with the same transmitter or group of transmitters; and
● the same identification number is assigned to the antenna used with each receiver.
Section 7 Unacceptable level of interference
In radiocommunications, it is unrealistic to expect to eliminate all possible interference in reception all of the time because of the ubiquitous nature and propagation characteristics of radio emissions. For this reason, the Determination aims to establish technical rules which allow licensees to manage interference within acceptable limits.
This section provides a technical definition of what will be deemed unacceptable levels of interference for the purpose of interference management in this band. A transmitter producing emissions that are found to cause unacceptable levels of interference to other services are not likely to be registered on the Register for operation in the band. Licensees who operate such devices without registration may become subject to prosecution under the Act.
Under section 7, a transmitter is taken to be causing unacceptable interference if:
● the operation of the transmitter breaches the core conditions of the licence. The core conditions define the geographic area and bandwidth of the licence and the maximum permitted levels of radio emission outside the geographic and frequency boundaries of the licence; or
● the device boundary of the transmitter exceeds the geographic boundary of the licence. The ‘device boundary’ is a theoretical boundary calculated around the device using the methodology set out in this Determination; or
● the device is a mobile or portable transmitter exceeding certain emission levels specified in the Determination.
A note to this section clarifies that certain kinds of transmitters are exempt from the registration requirement. These include, for example, mobile phone handsets and subscriber stations in broadband wireless systems. These devices are exempt because they have a low interference potential.
Section 8 Emission designator
This section explains how to work out the designation of a transmitter’s emission for the purpose of device registration. The emission designator is a series of alphanumeric symbols used internationally by the radiofrequency industry to classify the type and bandwidth of a radiofrequency emission.
Schedule 1 Centre location and effective radius of a transmitter
This Schedule defines the centre location, in terms of the location of the antenna in latitude and longitude, and effective radius of a transmitter (and for a group of transmitters) for use in determining unacceptable levels of interference under section 7. The effective radius of a transmitter can range from zero for a single fixed transmitter up to the greatest distance from the centre location of a group of transmitters to the location of any transmitter in the group.
Schedule 2 Device boundaries
This Schedule sets out the technical procedure for calculating the device boundary of a transmitter. Under subsection 7 (3), a transmitter is taken to cause an unacceptable level of interference if its device boundary exceeds the geographic boundary of the spectrum licence. Under subsections 7(3A) and (3B), where they apply, a transmitter is taken to cause an unacceptable level of interference if its device boundary exceeds both the geographic boundary of a licence and the geographic boundary of the licence area adjacent to the spectrum licence.
Part 1 of the Schedule details the steps involved in the device boundary calculation. The calculation is an iterative process and involves testing whether the device boundary criterion specified in Part 2 is met at increasing distance from the transmitter along radial lines spaced at 2.5 degrees around the centre location of the transmitter.
Part 2 provides the mathematical expression for determining the device boundary criterion. The criterion is achieved when the received signal along a radial reaches a target interference limit. The received signal level is calculated using the equations for propagation loss in Part 3.
Part 3 provides the mathematical equations for working out the propagation loss in the band when calculating the device criterion of Part 2. Calculation of propagation loss is based on an internationally recognised Deygout method for diffraction loss with a maximum of three obstructions.
Schedule 3 Average Ground Height and Transmitter Antenna Height
This Schedule specifies the procedure for calculating ground and transmitter antenna heights for use in working out the propagation loss in accordance with Part 3 of Schedule 2 of the Determination.
These heights are calculated with reference to a digital elevation model source from Geoscience Australia and are made available to all spectrum licensees to ensure consistency in application of the propagation loss calculations.
Schedule 4 Overview of Propagation Loss
(Modified extract from Rec ITU-R P.526.8)
This Schedule provides a descriptive overview of the methodology for calculating propagation loss set out in Part 3 of Schedule 2 of the Determination. It is intended to assist the reader in understanding the methodology for calculating propagation loss.