Leading the way to 5G through standardization

Operators around the world are currently preparing for the move from 4G to 5G. As you might already know, the next era of mobile networking promises ultra-fast data speeds and low latency. As a result, 5G will pave the way for major advancements in areas as diverse as self-driving cars, telemedicine, augmented reality, and much more.

I feel like it's so easy to describe the future impact of 5G that you'd almost be forgiven for assuming that its development and standardization was an overnight success. Of course, this couldn't be further from the truth.

The 5G standardization process is complex and involves countless stakeholders across diverse industries. Each have different but sometimes overlapping requirements. Complex is an understatement.

Despite the challenges, we've managed to develop a standard that meets the needs of industry and society, now and in the future. In the coming series of posts, my colleagues and I will outline some of the important contributions we've made to standardization. Here, I'll begin by summarizing how the 5G process works and then go on to describe LTE/NR interworking — a key contribution we made to the internal pre-standardization concept which eventually became an important feature of 5G today.

Foundation is key

Standardization is critical in the mobile telecommunications industry. At its core, standardization is the process of researching, developing and implementing technical standards based on the consensus of different parties that include influential 3GPP players, vendors, operators and other interest groups.

In essence, standardization maximizes technology compatibility, interoperability, security, repeatability and quality. The standardization of 5G started in 2016 and is still ongoing.

In order to get a fuller sense of the 5G standard we have arrived at today, and our contribution, we need to take a step back and examine what we did first to get here.

Collaboration with standardizing stakeholders

We were deeply involved in all areas of the standardization process. Over the years, we've been committed to working with all the parties involved in 3GPP and to the standardization of 5G.

3GPP is the standardization body responsible for the global standardization of 2G, 3G, 4G and 5G. 3GPP started as just one of several organizations for standardizing mobile technology. However, it is today the only remaining organization that every relevant company participates and liaises with.

For us, it has been critical that we realize not only the commercialization of 5G technology, but also that we agree on a standard that enables the full potential of the Internet of Things.

Ericsson's role in paving the way for 5G

To facilitate the efficient and successful introduction of LTE/NR interworking, we coordinated with major operators and vendors, in order to share ideas and discuss what we all wanted to achieve with 5G.

During these meetings we learned that some operators had expressed concerns about the migration from 4G to 5G and the potential impact on their network. We already knew that most operators didn't want to build out a fully dense network immediately with new technology.

At Ericsson we set about researching how to make it easier and quicker to use 5G during this migration phase. We thought combining 5G with an existing LTE deployment would prove useful and that combining the high and low frequencies during migration would strengthen network performance.

During migration, we noted that when 5G was introduced in high frequencies that it can suffer from spotty coverage which can make it difficult to build out a wide coverage network.

We concluded that it would be beneficial if you can start deploying at hot spots where there are a lot of users and traffic. In such locations you can quickly and seamlessly fall back to the existing LTE network when users start to move around to places where there is less traffic.

With all of this in mind, we set about researching and presenting argumentation for the inclusion of additional 5G features during offline discussions with interested parties and later 3GPP meetings. We were confident that including some of our ideas for new features in 5G would make the transition from 4G to 5G easier and more reliable for operators.

LTE/NR interworking

Since this was our idea, we took responsibility for the LTE/NR interworking and drove it from internal concept work through pre-standardization. We then took the lead in the discussions within 3GPP. During the study item phase, architectural aspects of LTE/NR interworking was agreed, to a large extent because of Ericsson's input in, for example, R2-162753, R2-162754, R2-164005, R2-164027 etc.

During the work item phase, Ericsson as RRC rapporteur took the lead in the RRC specification work and contributed significantly to set the RRC structure (R2-1708036, R2-1711532).

Also, the bearer harmonization concept, simplifying the handling in UE of the different bearer types originated from Ericsson (R2-1713906). In the end LTE/NR interworking became a hugely important addition to the 5G standard to ensure the fast rollout of NR.

Features and benefits

LTE/NR interworking is a feature of 5G that enables it to:

• leverage 4G deployments when deploying 5G on higher frequency (co-sited and non-co-sited)
• combine high and low frequency access to provide robustness against spotty 5G coverage
• increase capacity and performance by offloading User Equipment (UEs) from 4G to 5G

One of the main situations where LTE/NR interworking is widely considered valuable is in LTE/NR dual connectivity, known in 3GPP as EUTRA-NR Dual Connectivity (EN-DC), in which user data can be exchanged between a mobile device and an NR base station along with the LTE connectivity. In its simplest form, it enables two base stations to simultaneously deliver user data to a mobile device.

One key driver for the EN-DC architecture was that it enabled UEs connected to Evolved Packet Core (EPC) to use NR. In EN-DC, UEs use legacy procedures to connect to LTE and EPC, and then in a second step the network sets up the dual connectivity operation by configuring the UE with a secondary NR cell group. This allowed operators to roll out NR without having to wait for the completion of the 5G core network standardization.

In summary, the key benefits of LTE/NR interworking are the ability to:

• leverage on installed LTE base
• allow initial NR deployments
  • before 5G Core Network (5GC) is ready
  • with spotty NR coverage
• support LTE/NR aggregation
  • lack of NR spectrum in low/mid band (3-6 GHz)

Sharing standardization expertise and insights

The inclusion of LTE/NR interworking as a key feature of 5G was hugely important for the ICT industry and for Ericsson. But it wasn't our only contribution to 5G. Highlighted below are some of Ericsson's other key contributions to the standard that will have a great impact on performance:

• 5G Standalone – will enable aggressive radio interface performance targets. This is made possible by our flexible and scalable numerology, which is compatible with LTE and ultra-lean transmissions
• The full 3GPP Release 15 New Radio (NR) - will enable stand-alone NR with user and protocol plane using the 5G next-generation core network
• 5G security – will improve subscriber untraceability, protection of subscriber identities and subscriber privacy. It also creates flexible identity management where different types of credentials can co-exist and function over a variety of access types
• 5G sustainability – will introduce a fundamental change of design principles from "always on" to "always available" resulting in high energy savings
• 5G core – will, with the concept of network slicing and distributed cloud, adapt to business environments that are significantly different from the business environment of today

With each new release of 5G this list is expanding. Of course, none of this could have been achieved without a dedicated and talented team of Ericsson experts. So, while I'm proud to have played my part in this success, I'm not alone.

Depth of expertise

Right now, we have hundreds of employees who work with standardization in a wide variety of roles at Ericsson. Most of these are technical specialists, either working directly within the 3GPP process, or supporting our 3GPP work from within Ericsson. And, as is the nature of our work, we're never done. With each new release, we're constantly finding things to correct, optimize and improve.

Currently, we are working with three things: the main work is on the current release, i.e., Rel-16, which is the first evolution of NR. Typically, we have a lot of ideas, which we can't always squeeze in to the first release. So, we are also always looking at ways to introduce improvements in each new release. Secondly, maintenance work of the release 15 specification is still ongoing. There we clarify and potentially correct the NR standard with respect to issues, which have been identified during implementation and inter-operability testing. Lastly, we have already begun working with release 17, which is scheduled to start in 3GPP in 2020.

5G standardization research and development continues

We're able to spearhead the development of 5G because we continue to invest our competence and R&D in this important area. Our commitment to 5G standardization is ongoing and is not limited to R&D or our presence in 3GPP. It is also evident in the impact we've had on 5G and in the partnership numbers we have across the industry.

To date, Ericsson have signed 43 operator Memorandums of Understanding, have four industry partners and work with more than 20 universities and research institutes – and these numbers are constantly growing.

In future blog posts we'll explore other areas where we've contributed greatly to standardization.

Related links:

• LTE-NR tight-interworking and the first steps to 5G
• R2-162753, Tight integration of the New Radio interface (NR) and LTE: Control Plane design, Ericsson, 3GPP TSG-RAN WG2 #93bis, Dubrovnik, Croatia, 11 – 15 April 2016
• R2-162754, Tight integration of the New Radio interface (NR) and LTE: User Plane design, Ericsson, 3GPP TSG-RAN WG2 #93bis, Dubrovnik, Croatia, 11 – 15 April 2016
• R2-164005, Overview of RRC architecture options for the LTE-NR tight interworking, Ericsson, 3GPP TSG-RAN WG2 #94, Nanjing, China, 23-27 May 2016
• R2-164027, Tight integration of NR and LTE User Plane design, Ericsson, 3GPP TSG-RAN WG2 #94, Nanjing, China, 23-27 May 2016
• R2-1708036, [NR-AH2#12][NR] RRCConnectionReconfiguration structure - Email discussion summary, Ericsson, 3GPP TSG-RAN WG2 #99, Berlin, Germany, 21 – 25 August 2017
• R2-1711532, Summary of email discussion #30 for RRCConnectionReconfiguration, Ericsson, Ericsson, 3GPP TSG-RAN WG2 #99bis, Prague, Czech Republic, 9 -13 October 2017