How to understand 5G air interface (NR)?

The telecommunications industry certainly hopes to deploy 5G services with the support of ultra-high capacity and low-latency next-generation networks, but before 5G is commercially available, the technology needs further standardization work, and the current 5G standardization work organization is mainly 3GPP. 3GPP focuses on different technologies, service quality, and many other low-level technical topics such as 5G interoperability. The main research projects of 3GPP can be divided into 3 parts: radio access, core transport network, and services. In this article, I will try to discuss the future development and explore the standards of 5G NR.

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How to predict the future of 5G?

Today we can identify three pillars of 5G development. The first is enhanced mobile broadband (eMBB), which is expected to enable data connectivity to a whole new level. The second is mission-critical services, such as critical communication latency and extreme reliability applications, such as robotics and medical technology applications. The third is the Internet of Things related field, where we hope that 5G can meet the transmission speed under large device density. These are very diverse applications, and 5G is the technology that covers them.

As we can see new opportunities in 5G deployment, it is difficult to accurately predict future prospects and shifts in consumer spending behavior due to the complexity of emerging technologies.

Just like the LTE standardization work started in 2004, it was also before the “smartphone era”. At that time, we were only concerned with how to predict and drive drivers such as video and innovative applications to evolve and drive mobile users to consume more data. This is why we need to creatively combine next-generation technologies.

The current state of the industry development is very similar. We hope to enter a new era, where self-driving cars, automated transportation, medical applications, public safety and other uses are very demanding, and there will be huge connectivity needs in the emerging private IoT network field. 3GPP is currently creating a very effective environment that meets the needs of IMT-2020, just as the initial stage of 3G/4G networks. 3GPP has also agreed on a project to consider 5G unlicensed frequency band operation.

Will NR in unlicensed spectrum bring completely new opportunities?

In short, the vision of 5G NR is to provide low latency, high reliability and security services at a lower cost. The entire architecture is designed in a way that it can be extended to a large number of connected IoT devices to provide innovative services not only in the telecommunications field, but also in vertical fields such as health, automobiles, public safety, etc.

Let's take a brief look at the important decisions made by the 3GPP plenary meeting. Release 14 is the upcoming release, which will focus on features such as intra-band/quad-band carrier aggregation and enhanced V2X services. Release 15 is being planned, and the normative work of NR will appear in this version.

Some initial 5G NR requirements are as follows:

As manufacturers and operators are pursuing deployment as soon as possible, 3GPP decided to conduct non-independent operation around December this year, which will rely heavily on LTE as a "control plane host" to achieve tasks such as existing EPC mobility management. It will then independently complete target use cases such as eMBB and URLCC, with a frequency range above 6 GHz.

There is increasing interest in unlicensed spectrum and the new paradigms that NR can bring, and this area is currently an open research project, the final scope is very broad and still TBD. The extended service access to unlicensed spectrum will cover a specific range, covering low frequency and millimeter wave bands.

But the problem with unlicensed spectrum is that there is no arbitration and utilization is not very good. Especially when the load is very high, utilization becomes very low because all users are treated equally. Once unlicensed spectrum is unavailable, no one will be able to access it. While spectrum licensed by 3GPP is very expensive and fully regulated, operators have exclusive rights to it, so the main difference is whether QoS is guaranteed.

In between these two cases there is shared spectrum, such as 2.3 GHz in the EU and 3.5 GHz in the US, and now there are new modes and features to provide QoS for shared spectrum. At the Qualcomm NR Symposium, Juan Montojo gave an interesting example of "vertical sharing", which always favors high-priority operators but gives hosts access to secondary resources. Another mode is "horizontal sharing", where everyone uses WiFi like a Wi-Fi, but specific types of devices in the shared spectrum are targeted.

As we further improve the gap between QoS, shared spectrum can actually bring new opportunities through a combination of the above two models and innovative approaches.

When combined with technologies such as CoMP, where all the individual elements in a transmission collaborate to create value, the potential gains are very attractive. Exciting, however, 3GPP is considering NR implementations in unlicensed spectrum, which I believe will bring very broad market opportunities.