There are three key milestones in 2019 which will shape the way 5G networks are deployed and the use cases they can support in future. These are the next phase of Release 15 standards from the 3GPP; and two big decisions by the ITU (International Telecoms Union) – the selection of official IMT-2020 technologies, and the allocation of global 5G spectrum bands at the World Radio Conference 2019.
Both the ITU events will take place towards the end of next year, while the next stage in 3GPP standards-setting has been postponed by three months. The ‘late drop’ of specifications for Release 15 was due to be frozen at the turn of the year, but that will no happen in March.
Many of these developments will be predictable. The majority of the specs and the spectrum bands will be geared to conventional mobile operator business models and will largely build on what has already been done – shaped by the existing cellular industry – for LTE and early 5G.
But there are signs of disruption afoot too. Qualcomm has confirmed that the next full release of 5G standards – Release 16, due in 2020 – will include specs for 5G New Radio (NR) in unlicensed spectrum. Harnessing the Multefire technology which Qualcomm itself developed, those radios could even be deployed by non-MNOs (Multefire allows cellular technology to run in shared spectrum without an anchor network in a licensed band).
Meanwhile, four of the candidates to be anointed as official IMT-2020 standards (which means they must conform to a long list of requirements set by the ITU) are based on 5G New Radio (NR), sometimes in combination with LTE-Advanced. Those are being submitted by 3GPP itself, and by national bodies from countries which aim to be in the forefront of 5G technology and implementation – China, Korea and India.
But the fifth candidate is unrelated to 3GPP – and it does not come from the IEEE (many had expected a WiFi submission, but that has not transpired). Instead, it is from ETSI and the DECT Forum, with a proposal geared to IMT-2020’s IoT-related requirements, and based on the venerable technology best known in cordless phones.
The ETSI submission to IMT-2020 is based on DECT’s Ultra Low Energy (ULE) protocol, which the Forum argues is highly relevant to 5G applications in industrial, healthcare and other markets where there will be large amounts of IoT traffic indoors. The Forum is working on an interworking protocol, called DECT-5G, that would allow DECT and ULE to interface seamlessly with the 3GPP’s 5G NR, and in turn allow DECT-based applications to emerge wherever there was a 5G connection. The full DECT argument can be read here.
These examples show how MNOs will be challenged, not just in the commercial world – where webscale, enterprise and cable operators are looking to muscle in on the mobile value chain – but even in fundamental processes of standardization and spectrum allocation.
The prospect of 5G being deployable in unlicensed spectrum will help capitalize on the many opportunities emerging for private and industrial cellular networks, supporting specialized vertical market requirements. However, there were fears that 5G-Unlicensed would be pushed back to Release 17, and not make it into mainstream equipment and devices until 2022 or later.
But at this month’s 3GPP meeting in Sorrento, Italy, it was agreed to initiate a work item, called NR-U, which will define how 5G NR runs in unlicensed spectrum.
The work item covers six scenarios with different functionalities. These are:
- carrier aggregation within one eNodeB
- dual connectivity (across two eNodeBs)
- LTE anchor in licensed spectrum
- 5G NR anchor in licensed spectrum
- uplink only in licensed spectrum, downlink only in unlicensed spectrum
- standalone operation (no licensed spectrum anchor – clearly the most disruptive).
It will target the 5 GHz band, and also the 6 GHz band, which is just being opened up for unlicensed use in the USA, with other countries likely to follow. The WiFi community clearly hopes to dominate 6 GHz as it has 5 GHz, but may have to accept sharing it with cellular in the future.
There are more details from Lorenzo Casaccia, VP of technical standards at Qualcomm Europe, in this blog.
The sixth scenario is hugely significant for the industry, given that many of the 5G’s targeted applications are highly enterprise-driven – and are likely to be deployed more readily and innovatively if enterprise specialist providers are able to roll out networks. Qualcomm, until recently the least likely vendor to try to undermine the position of licensed spectrum and MNOs in the cellular market, has recognized that, and seen the opportunity to extend its platform to a new set of deployers in future.
This is the first time that 3GPP has set out to define specs for unlicensed bands. In the past, it has ratified technology developed externally, often to augment existing standards (as with LTE-LAA). Other developments for cellular in unlicensed have been developed by the industry but not standardized (as with Multefire).
Casaccia said in an interview: “To me, it was exciting because it’s really the first time for 3GPP to start a project to define a 3GPP technology for unlicensed spectrum”.
And of course, unlicensed spectrum can be a tool for MNOs, to supplement their licensed airwaves, boost their overall capacity and lower their total cost of data delivery. Early adopters of LTE-LAA (Licensed Assisted Access), which uses the 5 GHz unlicensed band as supplemental downlink for a licensed LTE network, say they have been able to support far higher data rates, with only a small additional cost of deployment and operation.
However, Casaccia is not sparing the MNOs’ feelings – he points to the likelihood that many enterprise, industrial and IoT requirements will be best served by specialist providers deploying localized, optimized networks that rely on the MNO mainly for wide area connectivity and roaming.
In the nearer term, the 3GPP is still working on Release 15, and the timelines are lengthening. The standards body has already published two waves of Release 15 standards for 5G NR – Non-Standalone (a fast-tracked subset which needs an LTE core), and Standalone, which also includes first specs for the 5G Core Network (CN).
But the work is not complete. Indeed, some say, with standards becoming so complex and multi-faceted, the process will never be complete and the 3GPP needs to emulate the IT industry and shift to a more ongoing system of updates rather than a hefty release every year or two. So a ‘final drop’ of specifications – those which are deemed necessary for Release 15, but would have delayed the standard significantly to be included in the initial publication – is still outstanding, and has now been delayed from year end to March 2019.
The need for the final drop, and now its delay, has led some to question whether the 3GPP’s processes are still fit for purpose, in an industry which changes so quickly and is trying to address the needs of so many users and industries.
The number of features that have needed to be standardized for 5G, and the number of submissions for each one, have been greater in 5G than 4G, by 10 times or more, say the companies involved in the 3GPP process. These changes show how complex this new network is, and how there will never be a ‘final’ set of specs to address all the requirements.
This issue is thrown into sharp relief when vendors and operators are also engaging with open source communities like the Linux Foundation’s LF Networking family of projects, which tend to have a faster, more fluid process (though with the downside of suffering from fragmentation).
At the Sorrento meeting, Balazs Bertenyi, leader of the 3GPP TSG RAN group, announced the change in deadlines but insisted it would not affect commercial deployments since these can go ahead without the final specs, and those can be added later in firmware.
“It is important to note, though, that this shift does not in any way impact the first 5G deployments,” he said. “The compatibility of devices and networks used for the first deployments are not impacted.”
The main features of the late drop relate to additional migration architectures to ease transition from LTE to the 5G core. The main reason for the delay was, apparently, that engineers were distracted by fixing some bugs in the Standalone 5G NR specs, which were frozen in September. In particular, questions were raised over backwards compatibility of equipment and devices supporting those latest specs, and those based on the earlier Non-Standalone platform.
“Over the course of 2018 3GPP RAN has put extreme focus on ensuring the stability and compatibility of these specification that are to be used for the first 5G deployments,” Bertenyi wrote in a blog post. “As a consequence, work on components for the ‘late drop’ that address additional architecture options to aid migration from LTE to 5G have been slightly delayed. Hence the freeze schedule for the Release 15 late drop was shifted by three months.”
Peter Clemons, chief designer of critical communications company Quixoticity, and a member of the RAN group, also said the delay – which will also push out Release 16 by at least three months – stemmed from “sheer workload”, and a lack of coordination between the different 3GPP TSGs (technical specifications groups) working on the 5G standard. As well as RAN, there are the SA (service and system aspects) and CT (core network and terminals) groups, but there was no time for a joint TSG coordination meeting in Sorrento.
Clemons told LightReading: “The enormous amount of work undertaken during Release 15 by RAN 1 and RAN 2 [TSG sub-groups] needs to be coordinated with SA 1 and SA 2, with CT also having a really hard job to make sure that rapidly changing standards are backwards compatible and forwards compatible.”
The new timetable sees a functional freeze for the full Release 15 now set for March, with the ASN.1 freeze following in June. (The 3GPP defines ASN.1 as covering protocols between the network and the user equipment, or between network nodes, while everything else is considered a ‘functional requirement’.) For Release 16, a functional freeze is now scheduled for March 2020 and an ASN.1 freeze for June 2020. The RAN TSG aims to approve a set of work items for Release 17 in December 2019.
Some critics think these delays are not just down to workload, but stem from when the 3GPP gave in to pressure from some operators, led by AT&T, to fast track the non-standalone variant of 5G NR. That led to concerns that this would distract from efforts to get the core network fully specified, and could delay availability of a total platform.
Mike Murphy, chief technologist for Nokia in North America, told EETimes that, in its rush to market, the 3GPP “tried to push the spec too quickly, targeting December last year, and as a side-effect a lot of change requests are coming through. People thought all the non-backwards compatible ones would be finished in June.”
When the 3GPP decided to do Non-Standalone first, some claimed the splitting of the NR work would delay essential aspects which should have been finalized in tandem with the radio. In particular, Nokia and others raised fears that the work on the packet core and the RAN was becoming too separate, because NR NSA does not require the 5G core. Enrique Blanco, CTO of Telefonica, argued when the split was announced in March 2017 that it was a backwards step, preventing 5G NR technology from evolving to support emerging use cases.
Later it emerged that some Release 16 work had been delayed because of the resources needed to get 5G NR NSA completed in time. At a plenary 3GPP meeting in Japan in November 2017, several study items were postponed. Bertenyi said at the time: “Given the challenges we have to finish Release 15 on time, we are going to put the study items on hold.” The delayed items included 5G-Unlicensed(now back on the agenda); non-terrestrial network (channel modeling); an enhanced V2X evaluation methodology; integrated access and backhaul; and non-orthogonal multiple access (NOMA).
Analysts at Signals Research Group (SRG) said delegates in Sorrento questioned whether the delays would affect the 3GPP’s ability to make its submission to the ITU-R for IMT-2020 status (the submission is based mainly on Release 16 specs, with some Release 15 and some LTE-A). “The only debate pertained to how this delay will impact the ITU-R submission for IMT-2020 status. There doesn’t appear to be any real concern among the 3GPP delegates since there is belief the IMT-2020 schedule is somewhat arbitrary and open to change,” wrote the analysts.