Proposed updates to RALI LM8 land mobile service frequency assignment requirements Discussion paperSEPTEMBER 2014

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Executive summary 1

IntroductionBackground 2Purpose

3

DiscussionUpdated frequency-distance constraints 4Height/power restrictions for high-power services 6Option to include terrain to optimise re-use distances 6Updates to intermodulation checks 6Clarifying arrangements for ambulatory systems 7Including basic checks and additional power constraints for supplementary transmitters 7

Summary of issues for comment

Invitation to commentMaking a submission 10

References

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Executive summary

This discussion paper invites industry comment on the proposed updates to the current frequency assignment requirements for the land mobile service contained in Radiocommunications Assignment and Licensing Instruction (RALI) LM8.(1)

These proposals support the implementation of changes to the 400 MHz administrative band plan in response to the 400 MHz review.(2) The proposed updates include: > new frequency-distance constraint tables for 6.25 kHz channels in the 400 MHz

band> the option to include terrain-based modelling to optimise frequency-distance

constraints when the impact of the local environment is considered significant> changes to intermodulation checks> clarification of arrangements for ambulatory systems> inclusion of basic checks and additional power constraints for supplementary

transmitters.

Apart from the changes resulting from the 400 MHz review, the Australian Communications and Media Authority (the ACMA) is also using this opportunity to propose updates to the existing frequency-distance constraints in the 400 MHz band and the VHF Mid and High bands. These updates are based on revised technical assumptions underpinning the frequency-distance tables to ensure consistency with the new 6.25 kHz tables. The new frequency-distance constraint tables for 6.25 kHz in the VHF High band has also been included as the equipment is now available.

The ACMA has based these updates—in particular, the updated frequency-distance values—on a specific subset of parameters from relevant standards and FCC Regulations. The accompanying report, Derivation of 400 MHz band land mobile frequency-distance constraints used in RALI LM8(3), provides the detailed derivation of these frequency-distance values. Industry comments are requested on the specific parameters and assumptions underpinning the proposed updates. Once finalised, proposed changes to frequency assignment practices will only apply to new assignments. Existing assignments will not require re-coordination and/or any changes to their operating parameters.

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IntroductionBackground400 MHz band planThe 400 MHz plan(4) specifies arrangements for radiocommunications services in the 403–430 MHz and 450–520 MHz frequency ranges. The plan specifies the service allocations in the two bands, the segment frequency limits applicable to these allocations and the channelling arrangements within these segments. The 400 MHz band review(2) has implemented a number of the major structural changes in the band, namely:> segments of the band have been identified for:

> the exclusive use of government to promote government harmonisation> rationalisation of spectrum use> efficient use of the spectrum> interoperability objectives

> a 10 MHz duplex frequency split has been implemented in parts of the 450–470 MHz band

> land mobile channel raster changes.

Detailed policy and transition arrangements in the 400 MHz band are outlined in The way ahead: Timeframes and implementation plans for the 400 MHz band, released in December 2010 (2).

Land mobile service in the 400 MHz band RALI LM 8(1) details frequency assignment requirements for the land mobile service. This RALI provides frequency assignment policy and coordination procedures for single and two frequency land mobile systems employing angle and digital modulation methods.

The RALI LM8 has been developed primarily for ACMA and accredited frequency assigners. It is also a useful guide for land mobile system planners. The RALI is based on relevant ITU-R work, the Australian experience in this field and other studies conducted by the ACMA and its predecessors.

The substantial structural changes articulated in the 400 MHz band plan have required a number of improvements to be implemented to the underlying assignment and coordination arrangements in RALI LM8.

A major change is a reduction in channel bandwidth to a minimum of 6.25 kHz, with a mandated maximum channel bandwidth of 12.5 kHz for land mobile services in high-and medium-density areas (HDAs and MDAs). The reduction of channel bandwidth in the land mobile service includes:> implementation of a 12.5 kHz channel raster (mandatory in HDAs and MDAs)> continued support 25 kHz bandwidth channels outside of HDAs and MDAs> support in all areas for the use of systems carrying two (or more) voice circuits

through a 25 kHz channel.

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PurposeThis discussion paper has been prepared in support of the ACMA’s review of arrangements for the land mobile service in the 400 MHz band. This follows the policy decisions, implementation plans and transition arrangements for the 400 MHz Plan.(1) The paper proposes consequential updates to the current frequency assignment requirements for the land mobile service contained on RALI LM8.

The ACMA is inviting industry comments on the following proposals:> new frequency-distance constraint tables for 6.25 kHz channels in the 400 MHz

band and the VHF High band, and updated frequency-distance constraint tables for 12.5 kHz and 25 kHz channels in the 400 MHz band and the VHF Mid and High bands, and technical assumptions used to derive the new and updated values

> updated height-power constraints> the option to include terrain-based modelling to optimise frequency-distance

constraints when the impact of the local environment is considered significant> changes to intermodulation checks> clarification of arrangements for ambulatory systems> inclusion of basic checks and additional power constraints for supplementary

transmitters.

The updated frequency-distance constraint tables for 12.5 kHz and 25 kHz channels are based on revised technical assumptions (transmitter emission masks and receiver selectivity) to ensure consistency with the new 6.25 kHz tables. The new frequency-distance constraint tables for 6.25 kHz in the VHF High band has also been included as the equipment is now available that can use segments B/H of this band.

This discussion paper should be read in conjunction with the updated RALI LM8 and the spectrum planning report Derivation of 400 MHz band land mobile frequency distance constraints used in RALI LM8 (3), which outlines input parameters, methods and calculations used to develop the frequency-distance constraints.

For additional information on assigning services in harmonised government spectrum in the 400 MHz, please refer to Frequency assignment practice, Guideline No. 4 — assigning harmonised government spectrum (HGS) in the 400 MHz band.

The proposed changes to RALI LM8 will only affect new assignments made after the updated document is in force. Existing systems coordinated under previous versions of RALI LM8 will not require re-coordination, and will not require any changes to their operating parameters.

To ensure the effectiveness of this consultation process, industry comments on the parameters and assumptions used to derive the updated frequency-distance values are as important a source of evidence as the comments on the specific frequency-distance values proposed.

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DiscussionThe majority of the proposed variations to LM8 discussed below are a result of decisions arising from the review of the 400 MHz band. Accordingly, the decisions below concern the detailed implementation of these changes in LM8.

Importantly, many of the proposed updates—in particular, the frequency-distance values—are based on a specific subset of parameters from relevant standards and FCC Regulations. These parameters include system parameters, transmitter emission masks and receiver selectivity.

The ACMA is not proposing mandatory compliance with these parameters and/or standards. However, operations with parameters other than assumed by the ACMA should not cause interference to other users and will only be protected to the extent provided for by the ACMA-assumed parameters.

Updated frequency-distance constraints The proposed updated frequency-distance constraints for land mobile systems in RALI LM8 include:> new frequency distance tables for 6.25 kHz channels to support the implementation

of changes to the 400 MHz administrative band plan> new frequency-distance tables for 6.25 kHz channels in the VHF High band as the

equipment is now available> updates to the existing frequency-distance tables for 12.5 kHz and 25 kHz

channels.

The updates to the existing frequency-distance tables for 12.5 kHz and 25 kHz channels are based on revised technical assumptions and calculation methods used to derive the frequency-distance values. This will ensure consistency with the new 6.25 kHz tables. In particular, the revised technical assumptions and methods include:> transmitter emission masks and receiver selectivity masks> sensitivity normalisation for different channels (system bandwidths)> adjustment to the Hata propagation model for Low Power Land Mobile Radio

Systems (LPMRS) to take into account the low (less than 30 metres) base-station heights in LPMRS systems

> slight adjustment to the method and software implementation of the method for calculating Frequency Dependent Rejection (FDR).

The following paragraphs summarise the specific subset of parameters and assumptions that have been used to calculate the proposed new and updated frequency-distance tables. More detailed analysis, including detailed calculation of frequency-distance constraints, is available in the accompanying spectrum planning report Derivation of 400 MHz band land mobile frequency distance constraints used in RALI LM8.(3)

Transmitter emission masks The following table summarises the emission masks used for calculating the proposed updated frequency-distance constraints in RALI LM8.

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Table 1 Transmitter emission masks for Land Mobile Systems in RALI LM8

Bandwidth Mask used

6.25 kHz ‘Mask E’ from FCC Part 90, Rule 90.210 (Emission masks)(5)

12.5 kHz ‘Mask D’ from FCC Part 90, Rule 90.210 (Emission masks)(5)

25 kHz(400 MHz)

Combined mask based on:> ‘Mask C’ from FCC Part 90, Rule 90.210 (Emission masks) (5)> FCC Part 90, Rule 90.221 (Adjacent channel power limits) (5)> Tetra emission limits (ETSI EN 300 392-2) (6)

25 kHz(VHF Mid and High)

‘Mask C’ from FCC Part 90, Rule 90.210 (Emission masks)* (5)(*the combined mask for 25 kHz system bandwidth has not been used for the VHF Mid and High Bands as FCC Part 90, Rule 90.221 is not applicable to the VHF Mid and High Bands)

The ACMA has also considered the relevant ETSI standards: ETSI EN 300 392-2 (6), ETSI EN 300 113-1 V1.7.1 (2011-11) (7) and ETSI EN 300 086-1 V1.4.1 (2010-06) (8). Detailed information and the diagrams of the three masks are shown in Derivation of 400 MHz band land mobile frequency distance constraints used in RALI LM8.(3)

Notably, the ETSI standards do not specify the transmitter emission mask to assess impact of emissions on systems occupying adjacent and other channels. Instead, ETSI sets limits for the adjacent channel (coupled) power, the power on any spurious emission, intermodulation attenuation and wideband noise limits. In addition, ETSI does not set limits, other than total transmitter power limits, to the transmitted signal level at different offsets within the authorised bandwidth.

ETSI power limits do not uniquely define the transmitter masks, especially when different system bandwidths coexist. For instance, a technology may exceed an emission mask under certain measurement conditions but may actually couple less power into a co-channel or adjacent channel system than would a technology that fits within the prescribed emission mask.

In general, the FCC masks (primarily designed for analog devices) appear to impose slightly less strict adjacent channel limits compared to ETSI. Using FCC masks for 6.25 kHz, 12.5 kHz and 25 kHz (VHF Mid and High) system bandwidths, and a combined mask for 25 kHz system bandwidth (400 MHz band), helps coexistence between different types of devices by avoiding interference, with a relatively small increase in coordination distances.

Receiver selectivityThe receiver selectivity requirements for land mobile systems appear not to be widely available in the form of the selectivity masks. The receiver selectivity masks used to calculate the proposed updated frequency-distance constraints are based on values given in ETSI EN 300 113-1 and ETSI EN 300 086; in particular, the receiver adjacent channel selectivity, intermodulation response rejection, spurious response rejection and blocking.

Propagation loss modelsThe service model for LPMRS (low power systems) in RALI LM8 specifies the base station effective antenna height as 10 metres. In order to calculate propagation loss for

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this service model, the modified Hata propagation loss model for urban environment has been adjusted for the base station antenna height lower than 30 metres, based on the ERC Report 68, Monte Carlo Radio Simulation Methodology(9).

Height/power restrictions for high-power servicesThe updated RALI LM8 introduces power restrictions for high-power base stations located with heights above average terrain greater than 450 metres, to limit interference to adjacent services:

Table 2 Height vs power restrictions for high-power services

Height above average terrain EIRP

≥ 450 m 41 Watts

≥ 550 m 20.5 Watts

≥ 650 m 10 Watts

Height above average terrain shall be determined by the procedure defined in ITU Recommendation ITU-R P.1546. Services located at heights above average terrain of 450 metres or more are considered to be high-power services for the purposes of licensing, charging and coordination, even though EIRP is reduced.

Option to include terrain to optimise re-use distancesThe updated RALI LM8 includes the option to use terrain-based modelling to optimise frequency-distance constraints when the expected impact of the local environment to the propagation path loss is considered significant. Some examples include: > a large mountain range offering additional propagation loss to/from a service in an

adjacent area> a transmitter located on a site at a height much greater or lower than the planning

model assumes> an anomalous propagation mode occurring due to a path over water.

Under such circumstances, modified frequency-distance constraints may be applied provided that interference to adjacent services is maintained to levels prescribed in the service model, and that service areas do not overlap (that is, a minimum of 80 kilometres separation is maintained for high-power services).

Propagation path loss may be determined using appropriate methods described in section 4 of ITU-R P.526 (versions 4 through 9) and a nine-second digital elevation model or better. Other methods for determining the propagation path loss may also be used with the agreement of the ACMA.

Updates to intermodulation checksThe proposed updates to intermodulation checks include: > updating frequency offsets from victim receiver, including values for 6.25 kHz

channel width> removing consideration of three-signal third-order receiver intermodulation> in cases where the prospective licensee of the new assignment is also the only

victim of any harmful intermodulation products, the licensee electing to accept any interference and proceed with the assignment

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> excluding ambulatory services from consideration when performing intermodulation checks

> updating the transmitter EIRP parameter values applicable to intermodulation checks.

The updated frequency offsets values are based on using 99 per cent power bandwidth to calculate offsets for different system bandwidths.

Three-signal third-order intermodulation checks have been removed as they are unlikely to cause interference issues. This is mainly due to the reduced probability of all three systems operating at the same time as the duty cycle for land mobile is generally low.

Clarifying arrangements for ambulatory systemsThe updated RALI LM8 introduces the service model description for the ambulatory services, specifying the key features of the model. In addition, the proposed update clarifies that:> ambulatory systems requiring coordination are coordinated as per the requirements

of the applicable model—that is, the Land Mobile Radio Systems (LMRS) or LPMRS model

> ambulatory services are excluded from consideration when performing intermodulation checks.

Including basic checks and additional power constraints for supplementary transmittersA supplementary transmitter is a transmitter intended to improve the service reliability within a 40 kilometre radius of the ‘parent’ base station. According to the proposed updates to RALI LM8, a supplementary transmitter still does not require full frequency coordination; however, checks to identify and mitigate against intermodulation issues should still be carried out.

In addition, the proposed update introduces the power restrictions to supplementary transmitters as per Table 3 below.

Table 3 Supplementary transmitter power restrictions

Distance (d) from base EIRP

0 ≤ d < 10 km 41 Watts

10 ≤ d < 20 km 20.5 Watts

20 ≤ d < 30 km 10 Watts

d ≥ 30 km Supplementary transmitters not permitted

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Height/power restrictions also apply to supplementary transmitters (see Table 4).

Table 4 Height vs power restrictions for supplementary transmitters

Height above average terrain EIRP adjustment

≥ 250 m -3 dB

≥ 350 m -6 dB

≥ 650 m -10 dB

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Summary of issues for commentThe ACMA is inviting industry comments on proposed updates to RALI LM8, the majority of which are a result of the decisions arising from the review of the 400 MHz band. Comments are also sought on the related underlying assumptions used to derive the new and updated values.

Issues for comment include:1. New frequency-distance constraints tables for 6.25 kHz channels and updated

frequency-distance constraints for 12.5 kHz and 25 kHz channels, in particular:> the assumed transmitter emission masks and receiver selectivity masks used

to calculate the new/updated constraints> the proposed new/updated values for frequency-distance constraints.

2. Power restrictions for high-power base stations located with heights above average terrain greater than 450 metres.

3. Option to use terrain-based modelling to optimise frequency-distance constraints when the expected impact of the local environment to the propagation path loss is considered significant.

4. Changes to intermodulation checks.5. Clarifying arrangements for ambulatory systems.6. Inclusion of basic checks and additional power constraints for supplementary

transmitters.

The ACMA also welcomes any other comments on the proposed updates to the RALI LM8.

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Invitation to commentMaking a submissionThe ACMA welcomes public comment on the proposals in this discussion paper to update frequency assignment requirements for the land mobile service (RALI LM8).

Submissions on the matters raised in this discussion paper and the draft RALI LM8 may be made to the ACMA as follows:By email: freqplan@acma.gov.au

By mail: The ManagerSpectrum Engineering SectionAustralian Communications and Media AuthorityPO Box 78BELCONNEN ACT 2616

The closing date for submissions is COB, Monday 3 November 2014.

Electronic submissions in Microsoft Word or Rich Text Format are preferred.

Each submission should specify:> the name of the individual or organisation making the submission> their contact details (such as a telephone number, postal address or email

address).

A submitter may claim confidentiality over their name or contact details or may make a submission anonymously or through use of a pseudonym by following the procedures outlined below (see ‘Publication of submissions’ and ‘Privacy’ below).

Media enquiries should be directed to Emma Rossi on 02 9334 7719 or by email to media@acma.gov.au. Any other enquiries may be directed by email to freqplan@acma.gov.au.

Effective consultationThe ACMA is committed to ensuring the effectiveness of its stakeholder consultation processes, which are an important source of evidence for its regulatory development activities. To assist stakeholders in formulating submissions to its formal, written consultation processes, the ACMA has developed Effective consultation—a guide to making a submission. This guide provides information about the ACMA’s formal written public consultation processes and practical guidance on how to make a submission.

Publication of submissionsIn general, the ACMA publishes all submissions it receives. The ACMA prefers to receive submissions that are not claimed to be confidential. However, the ACMA accepts that a submitter may sometimes wish to provide information in confidence. In these circumstances, submitters are asked to identify the material over which confidentiality is claimed and provide a written explanation for the claim.

The ACMA will consider each confidentiality claim on a case-by-case basis. If the ACMA accepts a claim, it will not publish the confidential information unless authorised or required by law to do so.

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Release of submissions where authorised or required by lawAny submissions provided to the ACMA may be released under the Freedom of Information Act 1982 (unless an exemption applies) or shared with other Australian Government agencies, and certain other parties, under Part 7A of the Australian Communications and Media Authority Act 2005. The ACMA may also be required to release submissions for other reasons including for the purpose of parliamentary processes or where otherwise required by law (for example, under a court subpoena). While the ACMA seeks to consult submitters of confidential information before that information is provided to another party, the ACMA cannot guarantee that confidential information will not be released through these or other legal means.

PrivacyThe Privacy Act 1988 imposes obligations on the ACMA in relation to the collection, security, quality, access, use and disclosure of personal information. These obligations are detailed in the Australian Privacy Principles that apply to organisations and Australian Government agencies from 12 March 2014.

The ACMA may only collect personal information if it is reasonably necessary for, or directly related to, one or more of its functions or activities.

The purposes for which personal information is being collected (such as the names and contact details of submitters) are to:> contribute to the transparency of the consultation process by clarifying, where

appropriate, whose views are represented by a submission > enable the ACMA to contact submitters where follow-up is required or to notify

them of related matters (except where submitters indicate they do not wish to be notified of such matters).

The ACMA will not use the personal information collected for any other purpose, unless the submitter has provided their consent or the ACMA is otherwise permitted to do so under the Privacy Act.

Submissions in response to this paper are voluntary. As mentioned above, the ACMA publishes all submissions it receives, including any personal information in the submissions. If a submitter has made a confidentiality claim over personal information which the ACMA has accepted, the submission will be published without that information. The ACMA will not release the personal information unless authorised or required by law to do so.

If a submitter wishes to make a submission anonymously or use a pseudonym, they are asked to contact the ACMA to see whether it is practicable to do so in light of the subject matter of the consultation. If it is practicable, the ACMA will notify the submitter of any procedures that need to be followed and whether there are any other consequences of making a submission in that way.

Further information on the Privacy Act and the ACMA’s privacy policy is available at www.acma.gov.au/privacypolicy. The privacy policy contains details about how an individual may access personal information about them that is held by the ACMA, and seek the correction of such information. It also explains how an individual may complain about a breach of the Privacy Act and how the ACMA will deal with such a complaint.

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References1. Australian Communications and Media Authority. Frequency Assigning Instruction for the Land Mobile Service (RALI LM8). 2000.2. Australian Communications and Media Authority. The way ahead—Timeframes and implementation plans for the 400 MHz band. 2010.3. Australian Communications and Media Authority. Derivation of 400MHz Band Land Mobile Frequency Distance Constraints used in RALI LM8. s.l. : Spectrum planning report SPPXXX, 2013.4. Australian Communications and Media Authority. 400MHz Plan (RALI MS22). 2012.5. FCC Regulations Part 90. FCC 90.210: Emission Masks; FCC 90.221: Adjacent channel power limits. 6. ETSI. ETSI EN 300 392 -2 V2.3.2(2001-03): Terrestrial Trunked Radio (TETRA) Voice plus Data (V+D): Part 2: Air Interface(AI). 7. ETSI. ETSI EN 300 113-1 V1.7.1 (2011-11) Electromagnetic compatibility and Radio spectrum Matters (ERM); Land mobile service; Part 1: Technical characteristics and methods of measurement European Standard . 8. ETSI. ETSI EN 300 086-1 V1.4.1 (2010-06): Electromagnetic compatibility and Radio spectrum Matters (ERM); Land Mobile Service; Part 1: Technical characteristics and methods of measurement. 9. ERC Report 68. Monte Carlo Radio Simulation Methodology. Naples : s.n., February 2000.

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