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MHz Band Submission by RF Communications Ltd

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MHz Band Submission by RF Communications Ltd Powered By Docstoc
					4RF Communications Response

Australian Communications and Media Authority
The 900 MHz band — Exploring new opportunities
Initial consultation on future arrangements for the 900 MHz band


June 2011
4RF Communications Ltd




Table of contents

Introduction .................................................................................................................................................................. 3
       Disclosure .............................................................................................................................................................. 4

Introduction .................................................................................................................................................................. 5
       Demand drivers ...................................................................................................................................................... 5
       Spectrum................................................................................................................................................................ 7

ACMA Consultation issues for comment................................................................................................................... 8


The 900 MHz band...................................................................................................................................................... 18
       4RF Experience ................................................................................................................................................... 18
       4RF Recommendations ....................................................................................................................................... 20

Summary .................................................................................................................................................................... 21




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Introduction




Prepared by:

John Yaldwyn
Chief Technology Officer
Director Regulatory Affairs
4RF Communications Ltd
John.Yaldwyn@4rf.com




4RF Communications Limited
26 Glover Street, Ngauranga, 6035
PO Box 13506, Johnsonville, 6440
Wellington, New Zealand
Phone    +64 4 499 6000
Fax      +64 4 473 4447
Web      www.4rf.com


Date:    June 2011




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Disclosure


4RF Communications Ltd has specialized in the design, development, and manufacture of point-to-point digital
microwave radio link systems for telecommunications networks for more than a decade. Our systems operate in
licensed spectrum bands that extend from 300 MHz to 3 GHz and are used in more than 120 countries. We not only
supply equipment but we also engineer, license, and install links for many customers. This activity has given us a
unique perspective on the deployment of medium to long haul links and practical regulatory considerations.



As a supplier 4RF has a vested interest in the availability of adequate spectrum for point-to-point links in the 900 MHz
band, but we sincerely believe that security and other benefits will accrue to Australia from the public safety and other
services that result from the utilization of this spectrum. Based on our worldwide experience we advocate a carefully
balanced approach to spectrum allocation, recognising the needs of suburban, rural, and remote areas of Australia for
long distance linking of the type that only the bands below 3 GHz, including 900 MHz, can offer.



4RF thanks the ACMA for the opportunity to comment on ‘The 900 MHz band — Exploring new opportunities’ initial
consultation discussion paper.



Where possible we have provided information gained from our worldwide deployment experience to indicate trends
which we hope will be useful to the review process.




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Introduction




Demand drivers




Public safety communications

Section 3b of the object of the Radiocommunications Act 1992 requires the ACMA to make adequate provision of
spectrum for use by public safety. In considering a TWS based approach the wider costs of a lack of effective
services needs to be considered in the total benefit of a regulatory decision. The fact that such costs are difficult to
quantify or that they may be funded from the public vote does not excuse consideration, particularly with such a
clearly overriding legislated imperative.

There is a lack of spectrum in Australia for the backhaul of new digital public safety communications systems, such as
the APCO P25 secure land mobile radio (LMR) standard. These new systems and the increased demands for
interoperability are stressing existing backhaul systems and expansion is necessary.

4RF equipment serves a number of state police and other public safety PPDR agencies protecting Australia through
day to day crime fighting and in natural disasters.

The ACMA initial consultation paper contains many examples of public safety use of the 900 MHz spectrum. What is
not shown is the recent growth in the use of 900 MHz fixed links by public safety agencies, particularly NSW Police,
which matches the roll out of digital secure LMR systems. This transition from analog to digital LMR will continue
throughout Australia, as submissions to the 400 MHz replanning process by public safety agencies has shown. A
second wave of analog to digital LMR transition will also take place as metro and city coverage is completed and
priority is given to rural and remote areas. 4RF believes from interaction with public safety agencies that while growth
in demand for 900 MHz fixed links has already been experienced, it will increase substantially as the coverage of
more difficult rural and remote areas is addressed.



Other users

A refocusing by major telecommunications providers, principally the incumbent, has seen the reduction and in some
cases elimination of leased circuit (PAPL, etc) services traditionally available to remote and rural Australia. Those
users who depend on private interconnections for land mobile radio and other connectivity are migrating to
replacement means based on fixed radio links, made possible with efficient digital fixed link products.




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Smart Grid

Recently the revitalization of the electricity network, a key component of Smart Grid activity, is driving renewed
demand for access to backhaul spectrum. The Smart Grid is not just about remote metering which may be amenable
to a uniform smart infrastructure, as suggested by ACMA CEO Chris Chapman in his speech to the National Smart
Grid Forum last year, but also includes a wide range of other initiatives that require microwave backhaul to help
manage new energy demands, enable renewable energy resources, improve security, and resolve faults more
effectively.

While the Smart Grid represents a diverse and growing demand for fixed link backhaul, other essential network
infrastructure upgrade efforts are being addressed by both the point-to-point medium to long haul 4RF products used
in the high voltage transmission and the medium / low voltage distribution networks as well as our range of point-to-
multipoint products. Many rural lines have nothing other than what the industry colloquially calls ‘customer telemetry’
to report faults. The introduction of automatic reclosers and new regulation equipment is improving the quality of
suburban and rural power but these systems place new demands on low to medium capacity backhaul.



Uncertainty

A negative demand driver expressed in many interactions with existing and potential users in Australia is ‘review
fatigue’ and uncertainty over the availability of spectrum to support apparatus based licencing of long distance private
microwave fixed links. Even major government agencies have expressed the view that they are unable to keep up
with what they see as a continuing review process of spectrum below 5 GHz suitable for long haul links and have, in
some cases, put deployment of services on hold because of this uncertainty.




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Spectrum


4RF first highlighted the growing demand for fixed service allocations to accommodate digital links in our response to
the 2008 ACMA commissioned consultant’s review of fixed point-to-point links in the microwave bands below 5 GHz.
4RF provided the consultant (Spectrum Engineering Australia Pty Limited) with information on activity in these bands
and with our views on future fixed link spectrum needs below 3 GHz.



Over the intervening years our predictions of growth have been met and exceeded. Based on the number of
deployments of our microwave equipment in Australia, 4RF can confidently state that the demand for fixed links below
3 GHz has grown substantially despite, although certainly limited by, spectrum availability uncertainty.



Growth is particularly notable in the last few years at 900 MHz in the two frequency fixed service driven by demands
for the back haul of public safety digital radio systems (refer Table 2.8 of the ACMA paper).



However, we see expressions of spectrum uncertainty amongst existing and potential licensees. We hope that a
positive review of the 900 MHz band will result in a considerable reduction in this uncertainty allowing more
confidence in the deployment of equipment in the two frequency single channel fixed service and the two frequency
low capacity fixed service allocations covered by RALI FX17 and SP 6/93 (as amended). In addition 4RF proposes an
immediate expansion of these allocations by retiring allocations made for outmoded and failed services, allocation for
which are currently wasting valuable spectrum.




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ACMA Consultation issues for comment




1.       The ACMA seeks comment on the proposed objectives of the review.

The proposed objects of the review are summarized as follows:

        improve the allocative, technical and dynamic efficiency of arrangements in the band by reviewing the
         relevant planning and licensing mechanisms

        align planning, licensing and pricing arrangements with current and anticipated demands, and support the
         latest technologies

        incorporate spectrum in the upper part of the digital dividend, which is not being included in the initial 700
         MHz band allocation, in order to expand services in the 900 MHz band

        improve the utility and flexibility with which the band is used.

The primary purpose of the digital dividend spectrum is to enable growth of cellular interests (CMTS). It is much
easier to plan for such services in the digital dividend spectrum after broadcast clearance than it is to displace existing
well utilized services in the 900 MHz band.

4RF welcomes the opportunity to expand existing services in underutilised parts of the 900 MHz band as set out in the
executive summary and indeed we have proposed expansion of the fixed link service.

The object to support the latest technologies is laudable; but 4RF is one example of a manufacturer who has
introduced new technology and yet the very spectrum needed to deploy this technology is under threat. Our
technology improves the efficiency, technical performance, utility, and flexibility of fixed link services.

The review paper notes the importance of PPDR activity but many of the proposed changes would have a detrimental
impact on the existing PPDR activities of the agencies charged with public safety in Australia.

4RF supports the rational review of spectrum allocations but we note with some trepidation that the results are not
always beneficial to all stakeholders and that unintended consequences often occur.

2.       The ACMA seeks comment on the merits of replacing the current frequency band plan with an
administrative plan.

There is a danger perceived with an administrative plan in that certainty of access for specific services is no longer
enshrined in law. This makes it difficult for smaller users to effectivly plan capital investment.




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3.       The ACMA seeks comment on the overall structure of the 900 MHz band and the current balance
between different services in the band.

As noted later in this response, the number of fixed service licences exceeds that of any other segment of the 900
MHz band (with the exception of the cellular CMTS segment) and there has been significant recent growth in the use
of fixed service licences at 900 MHz to support migration from analog to digital secure LMR systems by public safety
agencies in Australia. Demand will increase substantially as the coverage of more difficult rural and remote areas is
addressed. While the historical balance is just adequate now, expansion of fixed link services will be required to
support a wide range of activities from public safety through to revitalization of the electricity grid.

4.       The ACMA seeks stakeholder comment on any other technologies or regulatory measures that
should be considered as part of the 900 MHz review.

4RF recommends ‘use-it-or-lose-it’ style provisions in relation to valuable spectrum such as 900 MHz.

In the May 2009 Telstra submission on Release of the 3.6 GHz band for wireless access services (WAS) ACMA
Spectrum Planning Discussion Paper SPP 0209, the Corporation stated:

“Telstra continues to be a strong supporter of ‘use-it-or-lose-it’ provisions, including specified rollout obligations, to
optimise the efficiency of spectrum allocations in the medium and long term.

Because radio spectrum is a scarce, valuable national resource made available to licensees under various
arrangements, Telstra does not agree with ACMA’s premise that a licensee has a legitimate right to systematically ‘not
use’ radio spectrum assigned to it.”

We agree with the Telstra position but go further in advocating ‘use-it-or-lose-it’ provisions be applied to allocations
such as CTS and DSRR.

5.       The ACMA seeks comment on what, if any, regulatory measures should be put in place to facilitate
cognitive radio systems in the 900 MHz band.

Most cognitive radio systems sound superficially attractive but such systems add noise to the radio spectrum
increasing the noise floor for users who pay for spectrum to the detriment of their service.

The flaw with cognitive radio system implementation is how to define ‘unused’. It is very hard to consider the hidden
user who is receiving. For example with the white space concept there may be a user at the edge of a TV coverage
area happily enjoying a usable perhaps noisy picture in rural or outback Australia until an IEEE 802.22 based system
arrives and destroys his viewing.

The UK regulator Ofcom ran a consultation on cognitive access to certain spectrum, refer:

http://stakeholders.ofcom.org.uk/consultations/cogaccess/?showResponses=true

Responses were fairly predictable with existing spectrum holders (broadcasters) generally negative while potential IT
sector users were positive. It was notable that existing users generally have the radio engineering skills to properly
appreciate interference and propagation issues while IT sector responses were more broad brush.

It is hard to recommend any regulatory measure other than an outright ban until appropriately designed systems are
demonstrated.




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6.       The ACMA seeks comment on the option of extending consideration for allocations down to 803 MHz
rather than the current regional intention to maintain a guard band.

No comment.

7.       If allocations are extended to 803 MHz, what are the allocation options and associated coordination
requirements for potential services using the digital dividend and adjacent segments?

No comment.

8.       The ACMA seeks comment on the option to expand the 900 MHz band by 15 MHz to include 805–820
MHz. What are the costs and benefits of moving to such an arrangement?

The effect of this proposal would be to eliminate the present land mobile service and eliminate the present SCTF and
LCTF fixed link allocations currently in the paired spectrum (850 – 865 MHz). A detailed consideration of the SCTF
and LCTF allocations is contained in the responses to question 36, 37, and 38 below.

9.       The ACMA seeks comment on the possibility of enabling up to 2 x 15 MHz for new FDD services in
805–820 MHz paired with 850–865 MHz segment. How much of these segments should be replanned to
facilitate FDD services?

The effect of this proposal would be to displace the land mobile service and eliminate the present SCTF and LCTF
fixed link allocations currently in the paired spectrum (850 – 865 MHz). See the responses to question 36, 37, and 38
below.

10.      Information is sought on the issues that such a replan would raise. What are the costs and benefits?
How much time would be needed for the implementation of such a new arrangement?

This spectrum is not underutilised. A detailed consideration of the SCTF and LCTF allocations is contained in the
responses to question 36, 37, and 38 below.

11.      The ACMA seeks comment on the costs to services listed in Table 3.1 if they are required to migrate
out of the 850–865 MHz segment. What other spectrum could be used to continue these services?

The cost issue is partly considered in the response to question 38 but the true cost impact can only be accessed by
the SCTF and LCTF users themselves. In the future new spectrum for fixed links will be required below 3 GHz, the
question is where? One option is to plan fixed link allocations at 700 MHz in the digital dividend spectrum. 4RF is
currently supplying links to the US market in such spectrum so the concept is feasible but it has not been widely
considered.




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12.      The ACMA seeks comment on the possibility of using the 900 MHz expansion band, and the
segments currently allocated to the trunked land mobile service, to expand the spectrum allocated to the
cellular mobile telephone services (CMTS) by up to 2 x 20 MHz. This would result in up to 2 x 40 MHz of
spectrum being available for CMTS. How much of the 900 MHz expansion band should be allocated to CMTS?

This proposal would eliminate the trunked land mobile service and the present SCTF and LCTF fixed link allocations.
A detailed consideration of the SCTF and LCTF allocations is contained in the responses to question 36, 37, and 38
below.

The joint ETSI 3GPPP Technical Specification ETSI TS 136 104 LTE; Evolved Universal Terrestrial Radio Access (E-
UTRA); Base Station (BS) radio transmission and reception sets out the various frequency profiles to be deployed
throughout the world for LTE service.

There is no proposed profile that matches the proposed expansion of the CMTS spectrum; such a proposal would be
an orphan Australian allocation. The most logical place for the expansion of commercial cellular service is in the
digital dividend band spectrum below 803 MHz.

13.      Information is sought on the issues that would be raised by migrating land mobile services out of the
820–825 MHz paired with 865–870 MHz segments. What are the costs? How much time would be needed for
such a migration?

It is difficult to contribute to this question without knowing what alternative spectrum is proposed.

14.      The ACMA seeks information on the technical feasibility of a 5 MHz mid-band gap for CMTS. If not
achievable, what is the minimum size of a mid-band gap? Why?

No comment.

15.      The ACMA seeks comment on the possibility of using the 900 MHz expansion band to expand
trunked land mobile services.

4RF supports the suggested extension of the land mobile segments to include 816 – 820 MHz paired with 861 – 865
MHz. We note a large amount of commercial and public safety usage of the existing LMR allocations.

16.      How much of the 900 MHz expansion band should be allocated to trunked land mobile services?

An additional 4 MHz (816 – 820 MHz), as above, plus 4 MHz from the current outmoded CTS allocation (861 – 865
MHz) would seem reasonable given the relatively small size of the Australian allocation compared to that of the US.

17.      The ACMA seeks comment on whether channel spacing should be halved and arrangements be
based on 12.5 kHz and accommodate both analog and digital modulation.

This issue was studied by the New Zealand regulator, Radio Spectrum Management. Note that to facilitate continued
Tetra operation 25 kHz channels are required. The best measure of efficiency in this case is not channel bandwidth
but the number of voice equivalents supported.           The results of their study are available here:

http://www.rsm.govt.nz/cms/image-library/images-discussion-paper/digital-trunked-land-mobile-radio-in-the-800-mhz-ts-band




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18.      The ACMA seeks comment on whether the allocation to trunked land mobile should be retained or
revert to conventional land mobile.

From a purely technological perspective trunked operation would appear to be the best usage.

19.      The ACMA seeks comment on the possibility of using the 900 MHz expansion band for public
protection and disaster relief (PPDR) radiocommunication systems. How much of the 900 MHz expansion
band should be allocated to PPDR systems?

There seems no reason why PPDR digital secure LMR requirements could not be met by sharing the expanded
allocations of the existing trunked LMR service as proposed by Motorola.

Ironically, implementing the full APT suggestion would eliminate the SCTF and LCTF bands already used for backhaul
in support of PPDR activity.

Further the APT harmonisation suggestion already exists in practice as equipment from most of the trunked LMR
manufactures already covers the entire US LMR band of 806 – 825 MHz and 851 – 870 MHz thus covering existing
and proposed Region 3 allocations including the existing Australian allocations and proposed extension.

20.      The ACMA seeks preliminary information on the organisations that should be allowed access to such
an allocation and how it may be managed.

4RF is not well qualified to comment, but as an observation: the usual PPDR lead agencies with responsibility for first
response, support organisations such as USAR, SES, land SAR (not forgetting their volunteer components), and
perhaps Red Cross. Advisory groups such as the National Coordinating Committee for Government
Radiocommunications (NCCGR coordinating committee for interoperability) could be involved in management.

In considering PPDR interoperability it is not necessary for networks to be government owned. An excellent example
of a non-government owned network is the UK public safety network which is used by some 300 agencies. These
include the usual first responders of police, fire, and ambulance as well as RSPCA, some local council front line staff,
and even individual private practice doctors (in very remote areas). The advantages of such large trunking networks
are the shared infrastructure costs, centrally managed talk group access, and organization based encryption.      A
public private partnership model may be appropriate or an existing commercial network could be simply expanded to
provide a PPDR role.

21.      The ACMA seeks comment on whether there are other services that could make effective use of the
900 MHz expansion band. If so, what would be the best mechanism for giving those services access to the
band?

The LMR service could well be accommodated in the 805 – 815 MHz paired with 850 – 860 MHz as this is closely
aligned with the coverage of most existing LMR equipment, although the transition costs need to be considered.

The fixed service could use 815 – 824 MHz paired with 860 – 869 MHz (reduced by 1 MHz at the proposed top end to
allow for the CMTS ‘AMPS’ extension band) and this 2x 9 MHz arrangement would be a good improvement over the
existing 2x 5 MHz SCTF and LCTF arrangement. It would allow a complete restructuring of the SCTF and LCTF
services to embrace just 25 and 200 kHz channels (discussed further in the response to question 37) as well as
providing the opportunity to implement new efficiency standards. Again the transition costs need to be considered.




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One further advantage of this proposal is that it keeps the LMR service further away from the CMTS service. This
keeps the high power CMTS base transmitter stations (BTS) further away from the LMR mobile / portable receivers
reducing the potential for cellular BTS overload of LMR subscriber equipment. The fixed service is a good neighbour
for both the CMTS and LMR services because modern fixed service equipment utilises tight band pass RF filters and
the fixed service operates at relatively low power.

22.      How much of the 900 MHz expansion band should be allocated to these services?

4RF proposes below an additional allocation of 2x 2 MHz by eliminating part of the CTS and all of the DSRR
allocations. On an equivalent basis, repositioning as proposed above should deliver a minimum of 2x 7 MHz in total
for the fixed service.

23.      The ACMA seeks comment on the options for the future licensing of the 805–825 MHz paired with
850–870 MHz segments.

(a) What are the issues associated with the different options?

(b) What are the costs and benefits to stakeholders of different arrangements?

(c) Are there any other licensing options that should be considered?

The fixed service almost universally operates under apparatus licence conditions worldwide. While other licensing
options may reduce ACMA costs for apparatus licence management, spectrum licenses based on blocks immediately
disadvantages fixed service users as no one individual user would be likely to afford a 2x 5 MHz FDD block. Even
acting collectively the uncertainty introduced by any bidding process would be untenable.

24.      The ACMA seeks information on any other issues that would benefit from being considered in
reviewing arrangements in the digital CMTS segments (890–915 MHz paired with 935–960 MHz).

No comment.

25.      The ACMA seeks comment on the replanning of the 890–915 MHz paired with 935–960 MHz segments
using 5 MHz FDD paired blocks. Should this spectrum be replanned using 5 MHz FDD paired blocks? Should
the planning arrangement in Figure 4.2 with five lots of 5 MHz FDD paired blocks be used or is there another
arrangement that should be considered?

No comment.

26.      Information is sought on the issues that would be raised by moving towards the planning
arrangement in Figure 4.3, or any other arrangement it is believed should be considered. What are the costs
and benefits? How much time would be needed for such a migration?

No comment.

27.      The ACMA seeks comment on the option of changing licensing arrangements in the digital CMTS
segments irrespective of changes to planning arrangements. Information is sought on the preferred approach
to licensing these segments in the future.

No comment.




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28.      The ACMA seeks comment on the possibility of introducing spectrum licensing in the 890–915 MHz
paired with 935–960 MHz segments. If spectrum licensing is chosen to license this band into the future, which
allocation option should be used to establish new arrangements? Should it be one of the options detailed in
section 4.4.1 or another option?

No comment.

29.      Information is sought on the issues that moving towards a spectrum licensing regime in the 890–915
MHz paired with 935–960 MHz segments would raise. What are the costs? How much time would be needed
for such a migration?

No comment.

30.      The ACMA seeks comment on the desirability or otherwise of continuing an apparatus licensing
regime in the 890–915 MHz paired with 935–960 MHz segments. If apparatus licensing is continued, which
allocation method is preferred to establish new arrangements, if the segments are replanned as five lots of 5
MHz FDD paired blocks?

No comment.

31.      Information is sought on the issues that any change to current apparatus licensing arrangements in
the 890–915 MHz paired with 935–960 MHz segments would raise. What are the costs and benefits? How
much time would be needed to implement any changes?

No comment.

32.      The ACMA seeks comment on the preferred option for ongoing arrangements in the 890–915 MHz
paired with 935–960 MHz segments. If this involves a variation to current arrangements, what issues
associated with such a change should be considered in developing a transition plan? What are the costs and
benefits? How much time would be needed to implement any changes?

No comment.

33.      The ACMA seeks comment on the proposed use of the CTS spectrum from 857–865 MHz for the
expansion of the 900 MHz band. Are there other higher value uses for this spectrum?

4RF urges ACMA to set aside 2 MHz of the CTS spectrum to be paired with 933 – 935 MHz for fixed links forming a
LCTF expansion band. This proposal is expanded upon in the 4RF Recommendations section below that follows
these comments.

34.      The ACMA seeks comment on the option of allocating all or part of the 928–933 MHz segment to
support smart infrastructure services. The ACMA also seeks information on the technical characteristics of
the technologies that would likely be used to support smart infrastructure in this segment, such as bandwidth
and power characteristics.

As noted elsewhere, Australia needs the existing SCTF and LCTF allocations that span 928 – 933 MHz range.




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Expansion of allocations to support smart infrastructure services could be considered by partial harmonisation with the
European short range device (SRD) allocation of 862 – 870 MHz. This suggests making 862 – 865 MHz available by
replacing the outmoded CTS allocation while not impinging on the LMR band presently starting at 865 MHz. 4RF
notes that the New Zealand regulator, Radio Spectrum Management, has adopted this approach and gone further by
allowing the use of 868 – 870 MHz band by SRD devices with up to 2 mW e.i.r.p. and 1% duty cycle overlapping the
existing NZ simplex land mobile radio allocation. If this sharing was acceptable to Australian LMR users then
complete harmonisation with the European 862 – 870 MHz would be possible.

The NZ study is available at:

http://www.rsm.govt.nz/cms/pdf-library/policy-and-planning/radio-spectrum/806-960-mhz-band-
replanning/Summary%20of%20Submissions%20and%20Conclusions.pdf

35.      Information is sought on the issues that an allocation to support smart infrastructure services would
raise. What are the costs and benefits? How much time would be needed to implement such an arrangement?

The proposed allocation would require the relocation of the fixed services that would be displaced. A detailed
response to this issue is present in the responses to question 36, 37, and 38 below.

36.      Should the current allocations to the fixed service be retained?

There can be simply no question of reducing the current allocation to the fixed service. Allocations within the 900
MHz band are key to the support of digital secure LMR and other infrastructure requirements for public safety and
indeed of other government / commercial applications.

The ACMA Five-year Spectrum Outlook 2009–2013 notes: ‘The fixed service is a radiocommunications service
between a fixed transmitter and one or more fixed receivers (P-P or P-MP). Fixed links are a fundamental
communications delivery technology for numerous spectrum users (including government networks, emergency
services, utilities, and mining operators), and act as a backhaul enabler for other radiocommunications networks
(including mobile telephony and satellite).’ [4RF emphasis added].

It seems illogical to consider removing the current allocations to the fixed service given the above ACMA statement,
the fact that the number of fixed service licences exceeds that of any other segment of the 900 MHz band (with the
exception of the cellular CMTS segment), and that there has been significant recent growth in the use of fixed service
licences at 900 MHz to support migration from analog to digital secure LMR systems by public safety agencies in
Australia. Demand will increase substantially as the coverage of more difficult rural and remote areas is addressed.

37.      If so, is the current balance of segment sizes and channel widths correct?

As noted in the 4RF Recommendations section below the migration from analog to digital modulation both for
transmission within the SCTF and LCTF bands and for the PMR services that these fixed link bands generally
support, stresses the current allocations and is exacerbated by the oversized notional antennas required for LCTF use
which hinders SCTF to LCTF transition.

Users of the 25 kHz SCTF allocations have expressed a desire for the additional capacity that could be obtained by
migrating to the LCTF allocation but this is frustrated by the jump in notional antenna size required.

SCTF users are required to employ antennas with good F/B ratio in High/Medium spectrum density areas with lower
performance Yagi types suitable for Low spectrum density areas.


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LCTF users are required to employ a 2m grid pack antenna in High/Medium spectrum density areas with the
possibility of relaxation in Low spectrum density areas if adequate justification is provided (ACMA Advisory Note AW
Jan 2003).

To avoid re-engineering existing LCTF licenses and to relieve congestion of the SCTF band 4RF proposes a LCTF
expansion band with notional antennas requirements reduced to meet the specifications of RALI FX17. While reuse
efficiency through minimum antenna specifications is recognised so should practical deployment. Other reuse
efficiency measures such as better interference protection ratios could be considered. This proposal would allow
existing SCTF installations to be migrated to the proposed LCTF expansion allocation without changing antennas in
Low spectrum density areas and allow smaller sized and hence more practical grid and corner reflector type that still
retain good pattern and F/B ratios in High/Medium spectrum density areas.

As demonstrated in the 4RF recommendations section below that follows these comments, practically the only
channel sizes used in 900 MHz fixed link operations worldwide are 25 kHz and 200 kHz. Therefore the proposed
LCTF expansion band should only be channelled for 200 kHz with the migration of users from the 25 kHz channelled
SCTF band expected to reduce congestion in the SCTF band.

38.      What would be the cost of relocation of fixed services if they are displaced as a result of other
planning options discussed in this paper?

While fixed service bands exist other than at 900 MHz, only those fixed service bands below 3 GHz have the right
combination of distance capability and implementation cost to meet the need of long distance point-to-point radio links
required in rural and remote Australia. While high frequency fixed service systems at 7 GHz and above can provide
adequate capacity, the distance capability is limited. Traditionally long haul microwave links have been
accommodated at 1.5 GHz and around 2 GHz but ACMA spectrum embargoes and other restrictions on this fixed
service spectrum makes these backhaul systems increasingly difficult to engineer.

To implement equivalent links at 7 GHz and above additional sites and towers are almost always required. Given the
coverage radius of LMR sites backhaul links of many tens of kilometres, sometimes in excess of one hundred
kilometres, are required. At 7 GHz hops of a few tens of kilometres are possible but to implement 7 GHz hops at 50
km or more is expensive as the large dish sizes need substantial towers to accommodate wind loading and off
pointing requirements.

In the 4RF Experience section below, the section on Antenna systems illustrates the key driver for the increased
cost of implementing long haul links at 7 GHz and above. Not shown is the cost of implementing new green field sites
should long single hop 900 MHz links be required to be replaced with two or more 7 GHz links. These costs are
difficult to assess but run to hundreds of thousands of dollars per site, depending on location, site acquisition costs,
implementing access to mains power, and many other factors.

39.      The ACMA seeks information on services that could potentially utilise the 928–935 MHz segment.

Australia needs the existing SCTF and LCTF allocations that span 928 – 933 MHz range.

4RF urges ACMA to set aside the 2 MHz DSRR 933 – 935 MHz spectrum to be paired with 857 – 859 MHz for fixed
links forming a LCTF expansion band. This proposal is expanded upon in the 4RF Recommendations section below
that follows these comments.




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4RF Communications Ltd




40.      Information is sought on the issues that an allocation to these services would raise. What are the
costs and benefits? How much time would be needed to implement such an arrangement?

The benefit of turning over the unused DSRR spectrum to the fixed service would be immediate as the cost is low and
users could take advantage of the new spectrum with little delay.

Viable spread spectrum and cognitive radio systems require more than the 2 MHz the DSRR spectrum would provide.
For the reasons set out elsewhere it is hard to imagine technology both unproven in application and design displacing
existing systems in the SCTF and LCTF bands critical to life and safety in Australia.

Should alternative spectrum become available for fixed links, such as that proposed in question 21 (815 – 824 MHz
paired with 860 – 869 MHz) under an apparatus licence, then the proposed ISM/SRD expansion could be practical but
even then cognitive radio systems would most likely still be seeking more usable ‘white space’.

41.      The ACMA seeks suggestions for additional issues to be considered as part of the 900 MHz review.
What are the costs and benefits of any regulatory change associated with the additional issues?

4RF believes that effective use of the valuable fixed service allocations at 900 MHz requires attention to frequency
reuse and that notional antenna performance has a part to play here. However, antenna sizes need to be practical
and consistent with the service being delivered. Equally interference protection ratios contribute to reuse and these
need to be revised as equipment performance improves.

Given the limited nature of spectrum available to the fixed service modulation efficiency should also be improved. The
costs of reviewing these performance criteria would not be large (given industry contributions) while the benefits of
regulatory change would be the greater availability of frequencies.

Finally ‘use-it-or-lose-it’ provisions should be applied to apparatus licences as well as ‘tired’ allocations such as those
made for the outmoded CTS and DSRR services.




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4RF Communications Ltd




The 900 MHz band




4RF Experience


Deployment

Figure 1 below illustrates the relative popularity of various bandwidths for 900 MHz deployments made by 4RF
worldwide:




                          Figure 1 Worldwide 900 MHz 4RF deployments by bandwidth




4RF provides its customers a choice of channel bandwidths ranging from 25 kHz to more than 1 MHz in the 900 MHz
band. However, more than 94% of deployments utilise either 25 kHz or 200 kHz.



The narrow 25 kHz channel delivers 112 kbps at 64 QAM and is suitable for one and two channel analog/digital PMR
base station backhaul. The 200 kHz channel delivers 1,024 kbps at 64 QAM and is suitable for multi-channel analog
MPT1327 trunking and multi-channel digital PMR base stations, including those based on P25, Tetra, ETSI dPMR,
and NXDN technologies. Interface types may be analog, digital, Ethernet, or fractional E1.




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4RF Communications Ltd




Antenna systems

As the distance a link is required to cover increases antenna system costs begins to dominate. The cost of the
antenna system includes the antenna itself and the supporting structure. The structure, usually a pole or tower, must
be strong enough to manage the expect loads created by wind on the antenna without off-pointing. At 7 GHz and
above solid antenna types are used while at 3 GHz and below grid types are most popular.




These two graphs illustrate why; as the antenna size increases the wind load of the solid types increases more rapidly
than equivalent sized grid types. Frontal loading (FAT) can be reduced by as much as 75% while turning force (MT)
reduced by as much as 85% based on average figures calculated from multiple antenna manufacturers at a maximum
of 200 km/hour wind speed. The large reduction in force experienced using grid types dramatically reduces the cost
of the supporting structure hence the cost of long distance links at 900 MHz compared with 7 GHz and above.




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4RF Communications Ltd




4RF Recommendations




        There are more than 2,000 assignments in the Single Channel Two Frequency (SCTF) fixed link service at
         852 – 853.5 MHz paired with 928 – 929.5 MHz arranged as per RALI FX17

        ACMA must move to alleviate this overcrowding of the SCTF band

        We note that this number of licences exceeds that of any other segment of the 900 MHz band (with the
         exception of the cellular CMTS segment)

        Of the 10 top users of the SCTF allocation 6 are public safety users

        Adjacent is the Low Capacity Two Frequency (LCTF) band 854 – 857 MHz paired with 930–933 MHz
         arranged as per SPP 6/93

        The second and third largest users of the LCTF fixed link band are also public safety agencies

        The migration from analog to digital modulation, both for transmission within the SCTF and LCTF bands and
         for the PMR services that these fixed link bands generally support, stresses the current allocations and is
         exacerbated by the oversized notional antenna required for LCTF use which hinders SCTF to LCTF
         transition

        Additional point-to-point channels are required, as shown in Figure 1 the most widely used 900 MHz
         deployments worldwide are at 200 kHz

        The immediate removal of Embargo 34 and abandoning the outmode CTS and failed DSRR services would
         provide a 2x 2 MHz expansion with little or no impact on other 900 MHz replanning efforts including the other
         expansion of fixed link spectrum suggested by ACMA

        4RF propose a LCTF expansion band 857 – 859 MHz paired with 933–935 MHz with 200 kHz channelling
         and a reduced notional antenna size (to allow smaller sized grid and corner reflector types that retain good
         F/B ratios)

        While we appreciate that there are legacy CTS users it would appear CTS services are largely confined to
         metropolitan areas whereas the demand for an LCTF expansion band would be greatest in urban, rural, and
         remote areas.




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4RF Communications Ltd




Summary

As a supplier 4RF has a vested interest in the availability of adequate spectrum for point-to-point links in the bands
below 3 GHz, but we sincerely believe that economic and security benefits will accrue to Australia from the resulting
services.



We advocate a carefully balanced approach to spectrum allocation, recognising the obvious public value of large
users such as cellular as well as the contributions to the Total Welfare of Australia made by smaller individual users
such as public safety and other rural or remote users, both government and industry.



Within the 900 MHz band are the extremely valuable fixed link allocations with some of the highest Australian usage
(apart from cellular) and these are desperately in need of expansion. In exploring new opportunities for the 900 MHz
band we urge the ACMA not to overlook these existing users and to leverage allocations made for failed service to
alleviate overcrowding.




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