The Australian Communications and Media Authority (ACMA) has released its first discussion paper on the possibility of refarming the 1.5GHz and 3.6GHz spectrum bands for enabling 5G mobile broadband.
ACMA acting chairman Richard Bean said the federal government agency is looking into the matter now that international consideration of those spectrum bands has "progressed significantly", including by the International Telecommunication Union-Radiocommunication Sector (ITU-R), the Asia-Pacific Telecommunity (APT), and several nations.
"Given the momentum developing, the time is right for us to consider the potential for re-planning the bands in Australia," Bean said.
"There are international standards that support 4G technologies in both the 1.5GHz and 3.6GHz bands. Importantly, the 3.6GHz band is also being looked at internationally as an early band for 5G, and the ACMA has decided to bring forward discussion of its future use.
"Refarming these bands would enable additional capacity for new or existing operators' mobile networks."
The 3.6GHz spectrum band is currently used in Australia for fixed-line and satellite services, while the 1.5GHz band is used by the Department of Defence as well as for fixed-line services in regional areas.
In its discussion paper -- Future use of the 1.5 GHz and 3.6 GHz bands: Initial investigation of the 1427-1518MHz and 3575-3700MHz bands for mobile broadband services -- the ACMA outlined its preliminary investigation of each of the bands, including looking into what comparable nations are using the spectrum for.
Submissions from interested parties are due by November 25, with a decision on whether the ACMA will progress to preliminary re-planning due in January 2017. The ACMA would then release a second discussion paper in Q2 2017, with submissions on that due in Q3 2017, and a decision on whether to progress to refarming expected in Q3 to Q4 2017.
If the ACMA decides to go ahead with refarming those bands, commencement is expected in Q4 2017.
The ACMA is seeking comment on issues including whether it should progress from initial investigation to preliminary re-planning; whether the two spectrum bands should progress in parallel or the timing of one be prioritised above the other; whether specific issues could affect the timeframe; whether the Department of Defence expects future usage of the 1.5GHz band; what frequency arrangements should be adopted; what geographical areas should be refarmed and in what order; whether existing satellite and fixed services could be migrated to new or existing mobile networks; and what coexisting or sharing arrangements could be made across both bands.
At the beginning of October, the ACMA also released its five-year spectrum outlook (FYSO) and 12-month work plan, focusing on arrangements to support 5G, the Internet of Things (IoT), and dynamic spectrum access (DSA).
The ACMA said at the time that it is considering the use of millimetre wave (mmW) bands for 5G.
"Enabling the next phase of mobile network development is likely to require the ACMA's attention in a number of areas," the FYSO said.
"From a spectrum perspective, 5G appears certain to use (though not exclusively) large contiguous bandwidths (hundreds of MHz or more) in millimetre wave bands."
For IoT concerns, the ACMA is looking at a broad range of spectrum bands due to the large number of varied uses and users involved, and in the very high frequency (VHF) band.
"Given the huge diversity of uses of IoT, there is no simple solution to providing spectrum for all of the applications which are likely to require access to it under a range of protocols from dedicated spectrum to commons spectrum, and options in between," Bean said at the beginning of October.
"We are and have taken steps to make new spectrum available to support a range of low-power applications including M2M [machine-to-machine] applications in 900MHz band as part of the implementation of our review of the 803-960[MHz] band. Permanent arrangements in this band are not currently set to be in place until 2021, but we will consider early access applications."
In regards to DSA, the ACMA recognised spectrum sharing as being "fundamental" for efficient spectrum management for 5G and the IoT. DSA relies on users and uses to co-exist on the same spectrum band, with awareness of the environment required.
The ACMA said there are currently three ways for devices to become more aware of their surroundings to enable dynamic sharing of a spectrum band.
"At this stage, three major techniques to enhance a device's awareness of its surroundings have been identified: Geolocation with database look-up; sensing; and beacon transmissions," the FYSO says.
"These techniques can be used to make use of spectrum 'white space', where secondary users take advantage of intermittent, occasional, or itinerant use by primary users."
The ACMA in July said spectrum sharing is the key to IoT and 5G, with ACMA Spectrum Planning Branch executive manager Christopher Hose saying that there needs to be more cooperation between industry and the ACMA to achieve this goal.
The Department of Communications also recently announced that the ACMA will be auctioning off 2x 15MHz of the 700MHz spectrum band for mobile broadband that went unsold during the 2013 digital dividend auction, following Vodafone Australia's proposal to buy the spectrum outright.