79. This part of the guidelines applies to a licensee or an authorised person who intends to implement, or change the technical operating specification of, a digital television broadcasting service or datacasting service occupying a channel in the 174 to 230 MHz, or 520 to 820 MHz bands of the radiofrequency spectrum.
80. Unless otherwise specified in the technical specifications of the DCP (or approved implementation plan), the transmitter site shall be located within the licence area of the related licence or within the datacasting service area of the datacasting service, whichever is applicable.
Note The transmitter should desirably be located so that, for a particular broadcasting band, viewers within population centres of the licence area or datacasting service area are able to receive all television services licensed to serve that area by means of a single outdoor antenna appropriate for that band.
81. If a transmitter intended to serve a particular area is not sited at the nominal location, the ERP of the transmission in any given direction from the alternative site shall not exceed that specified for the nominal location in the DCP.
Note 1 Guideline 81 does not preclude a licensee from making an application to vary a DCP where operation at higher ERP levels is required.
Note 2 Guideline 106 deals with the situation where a licensee proposes to operate transmitters additional to those included in a DCP.
82. Under the policy objectives given in 6(3) (f) of Schedule 4 to the Broadcasting Services Act 1992, ‘.. as soon as is practicable after the start of the simulcast period for a licence area, and throughout the remainder of that period, the transmission of a commercial television broadcasting service in SDTV digital mode in that area should achieve the same level of coverage and potential reception quality as is achieved by the transmission of that service in analog mode in that area’. The DCPs provide the ERP levels expected to meet this objective, and where applicable, any ERP restrictions that need to be applied to protect specified analog television services from interference.
83. After the simulcast period mentioned in guideline 82, transmitters providing digital television broadcasting services (i.e. not datacasting services) which operate from a site, or sites, other than the nominal location(s) specified in the DCP shall at least provide a minimum level of service to those urban centres in the licence area of the related licence that would have received a service from a transmitter (or transmitters) operating from the nominal location(s).
84. For the purpose of application of guideline 83, the minimum level of service in an urban centre is achieved if the received median field strength is equal to, or greater than, the planned minimum field strength.
Part Part 6 - Technical Planning Guidelines (December 2003) - DIGITAL TELEVISION | Zoe
Note No Minimum Level of Service Requirements are applicable to datacasting services. However, protection of a datacasting service against interference from other services will only be provided on the basis that the datacasting service provides a median field strength equal to, or greater than, the planned minimum field strength.
85. In applying guidelines 82, 83 and 84, changes to sites or operating parameters of transmitters after the simulcast period should not cause a reduction in the level of service that was being provided during the simulcast period.
Table 6.1: Minimum median field strength figures for digital television
(50% of locations, 50% of the time, measured at 10 metres above ground level – see guideline 9)
| TV Transmission Band | Frequency Range (MHz) | Field Strength (dBµV/m) |
| III | 174 ‑ 230 | 44 |
| IV | 520 ‑ 582 | 50 |
| V | 582 ‑ 820 | 54 |
Maximum field strength within the licence area or datacasting service area
86. A transmitter shall be sited so that not more than 1 per cent of the total population receiving at least the planned minimum field strength reside in areas with received field strengths greater than 110 dBµV/m.
87. A transmitter shall not be sited so that a significant part of the population receiving at least the planned minimum field strength reside in areas with received field strengths greater than 120 dBµV/m (1 V/m). For the purpose of this guideline, 0.1 per cent of the population or 100 persons, whichever is less, constitutes a ‘significant part’.
Note 1 Guidelines 86 and 87 deal with potential interference and/or degradation in receiver performance due to excessive signal levels at the input terminals of the digital television receiver.
Note 2 The height of the antenna above ground level and/or the vertical radiation pattern may be altered to assist in complying with guidelines 86 and 87.
Maximum field strength beyond the licence area or datacasting service area
88. If a transmitter is sited at a location other than the nominal location, the licensee must ensure that the median field strength of the transmission in any urban centre beyond the licence area boundary or datacasting service area boundary (whichever is applicable) does not exceed the greater of:
the field strength, for the frequency band of operation, specified in table 6.1.
89. If there is no technical specification specified in a DCP for a transmitter, the median field strength of the transmission in any urban centre beyond the licence area boundary must not exceed the field strength for the frequency band of operation specified in table 6.1 unless otherwise specified in the transmitter licence conditions.
90. A licensee of a digital television broadcasting service or datacasting service shall not cause unacceptable interference to an analog television service that is:
being received within its licence area, national signal reception area or narrowcasting service area, as applicable; and
being received with median field strengths equal to, or greater than, the planned minimum field strength.
91. For the purpose of application of guideline 90, it is assumed that analog television services are being received using a television receiving system that has equivalent performance to the analog reference television receiving system. Where receiving systems are employed which have inferior performance to that of the analog reference television receiving system, or where their performance exceeds the performance of the analog reference television receiving system in ways that make them more sensitive to interference, interference protection will only be afforded to the level provided by the analog reference television receiving system.
92. For the purpose of application of guideline 90 to co-channel interference, ‘unacceptable interference’ means degradation in the ratio of the wanted to unwanted signals, at the receiver input terminals of an analog reference television receiving system, of 2 dB or more due to the unwanted service, where the resulting co-channel ratio of wanted to unwanted signals is 41 dB or less.
93. For the purpose of application of guideline 90 to adjacent channel interference, ‘unacceptable interference’ means that the digital television broadcasting service or datacasting service occupies a channel that is adjacent to an analog television service and the relative level of the unwanted digital signal is more than 5 dB above the level of the wanted analog signal when measured at the receiver input terminal of an analog reference television receiving system. This value applies equally for upper or lower adjacent channel combinations.
94. Practical application of guideline 93 should take account of variable factors affecting the relative levels of the received adjacent channel transmissions. Where adjacent channel transmissions are provided from a common antenna an allowance of 5 dB shall be applied (i.e. a ratio of wanted to unwanted signals of 0 dB). Cases involving transmissions from different antennas require case-by-case consideration.
95. Where the same set of analog television services can be received from more than one transmission site with signal levels above the planned minimum field strength, application of these guidelines shall ensure that the reception of at least one of the sets of services, but not necessarily all of the sets of the same services, is protected against interference from the unwanted service. Similarly, where multiple transmissions of the same analog television service can be received from a single transmission site with signal levels above the planned minimum field strength, these guidelines shall ensure that the reception of at least a UHF transmission is protected against interference from the unwanted service.
96. A licensee of a digital television broadcasting service or datacasting service shall not cause unacceptable interference to a digital television service or datacasting service that is:
operating within the terms of the relevant DCP (or approved implementation plan) or datacasting transmitter licence, as appropriate; and
being received within its licence area, national signal reception area or datacasting service area, as applicable; and
being received with median field strengths equal to, or greater than, the planned minimum field strength.
97. For the purpose of application of guideline 96, it is assumed that digital television services or datacasting services are being received using a television receiving system that has equivalent performance to the digital reference television receiving system. Where receiving systems are employed which have inferior performance to that of the digital reference television receiving system, or where their performance exceeds the performance of the digital reference television receiving system in ways that make them more sensitive to interference, interference protection will only be afforded to the level provided by the digital reference television receiving system.
98. For the purpose of application of guideline 96 to co-channel interference, ‘unacceptable interference’ means degradation in the carrier-to-noise-plus-interference ratio, at the receiver input terminals of a digital reference television receiving system, of 1 dB or more due to the unwanted service, where the resulting co-channel carrier-to-noise-plus-interference ratio is 20 dB or less.
99. For the purpose of application of guideline 96 to adjacent channel interference, ‘unacceptable interference’ means that the digital television broadcasting service or datacasting service occupies a channel that is adjacent to a digital television or datacasting service and the relative level of the unwanted digital signal is more than 30 dB above the level of the wanted digital signal when measured at the receiver input terminal of a digital reference television receiving system. This value applies equally for upper or lower adjacent channel combinations.
100. Practical application of guideline 99 should take account of variable factors affecting the relative levels of the received adjacent channel transmissions. Where adjacent channel transmissions are provided from a common antenna an allowance of 5 dB shall be applied (i.e. a ratio of wanted to unwanted signals of -25 dB). Cases involving transmissions from different antennas require case-by-case consideration.
101. If the operation of a transmitter causes unacceptable interference to a digital television service or datacasting service, the licensee must (at the licensee’s own expense) adjust, or fit devices to, the transmitter or the affected receivers, or undertake other measures in order to reduce the interference to a level that is no longer unacceptable interference.
Note Part 7 of these guidelines deal with the digital licensee’s responsibilities in the event of interference to an analog television service.
102. Where the same digital television service or datacasting service can be received from more than one transmission site with signal levels above the planned minimum field strength, application of these guidelines shall ensure that the reception of at least one of the signals is protected against interference from the unwanted service.
103. If a digital television broadcasting service or datacasting service:
does not provide a service from a transmission site included in a DCP technical specification; or
operates at an alternative site from that specified in the DCP technical specification; or
operates from an additional site not included in a DCP technical specification (see guideline 106), then,
the service will be afforded protection against interference from other digital television services or datacasting services included in the DCP based on the assumption that it is operating from the nominal location(s) included in the DCP.
104. In addition to the conditions of guidelines 90 to 103 (which relate to analog television services, digital television services and datacasting services), a licensee shall, in consultation with affected parties, resolve complaints of interference to other radiocommunication services where that interference is caused by operation of the transmitter pursuant to the licensee's digital television broadcasting service or datacasting service.
Single frequency networks and additional co-channel transmitters
Note 1 The ABA’s planning responsibility is limited to determining channels, nominal transmitter sites and radiation pattern envelope specifications. Detailed design and implementation of Single Frequency Networks (SFNs), including determination of relative ERP levels and timing relationships between signals from each of the transmitters within an SFN, is the responsibility of individual licensees.
Note 2 Through its DCPs the ABA has defined a set of channels, transmission sites and radiation pattern envelope specifications that will permit digital television and datacasting services to be provided. Where a digital television or datacasting licensee proposes to deploy additional transmitters on the same channel as an existing channel allotment within a DCP (i.e. transmitters in addition to those shown in the technical specifications associated with the DCP), it is the licensees responsibility to: ensure that these guidelines, which inter alia deal with interference to other services, are complied with; and, to design and site the additional transmitters to avoid co-channel or adjacent channel interference from other services within the intended coverage area of the additional transmitters.
105. A licensee of a digital television broadcasting service or datacasting service may configure co-frequency transmitters whose technical specifications are included in a DCP, into an SFN. However, the licensee is responsible for the detailed implementation and management of internal self-interference within the SFN.
106. A licensee of a digital television broadcasting service or datacasting service may be permitted to establish additional digital transmitters on the same channel as an existing channel allotment within a DCP assignment for that service (which may, or may not, be operated in an SFN arrangement), without requiring a variation to the DCP, subject to the following conditions:
the area to be covered is not adequately served by transmitters operating in accordance with the DCP technical specifications; and
Note 1 Guidelines 82 to 84 define the Minimum Level of Service Requirements for digital television broadcasting services. For the purpose of application of paragraph 106(a) to datacasting services, an area may be considered under served if the received median field strength is less than the planned minimum field strength.
Note 2 For the purpose of application of paragraph 106(a), an area may also be considered under served if an existing co-channel allotment determined in a DCP does not allow sufficient coverage due to self-interference.
transmitter licence applications relating to the additional transmitters are submitted to the ABA; and
the licensee is responsible for managing self-interference arising from the additional co-frequency transmitters, and for resolving co-channel or adjacent channel interference from other services within the intended coverage area of the additional transmitters; and
the characteristics of the additional transmitters comply with guideline 80 (Location of Transmitter Site), 86 and 87 (Maximum Field Strength within the Licence Area or Datacasting Service Area), 89 (Maximum Field Strength beyond the Licence Area or Datacasting Service Area), 90 to 104 (Interference to other Services), 107 (Radiated Signal Characteristics) and with Part 7 (Interference Management Scheme for Digital Television) of these guidelines; and
in addition to the interference conditions set out in guidelines 90, 91, 92 and 95 in respect of co-channel interference to analog television services, where the ratio of wanted to unwanted signals due to existing interferers is 41 dB or less, the interfering field strength from the proposed additional transmission is at least 6 dB below the root-sum-squared value of the existing co-channel interferers; and
in addition to the interference conditions set out in guidelines 96, 97, 98 and 102 in respect of co-channel interference to digital television services or datacasting services, where the ratio of wanted to unwanted signals due to existing interferers is 20 dB or less, the interfering field strength from the proposed additional transmission is at least 10 dB below the root-sum-squared value of the existing co-channel interferers.
107. The radiated signal characteristics of a transmitter shall comply with clause 4.8.2 (Aus) of section 3 of Australian Standard AS4599-1999 Digital Television – Terrestrial Broadcasting – Characteristics of digital terrestrial television transmissions (see appendix 4).
108. Australian Standard AS4599-1999 Digital Television – Terrestrial Broadcasting – Characteristics of digital terrestrial television transmissions provides for a range of options relating to modulation, code rate and guard interval. While other operating modes are not excluded, the ABA will apply a Reference Modulation for planning purposes based on modulation of 64-QAM, code rate of 2/3 and guard interval of 1/8. This leads to a minimum C/N requirement of 20 dB (including implementation margin) for receivers operating in Ricean channels. Operation with other parameters will only be protected to the extent provided by the Reference Modulation.