Shaping Future 6G Networks. Группа авторов

Чтение книги онлайн.

СКАЧАТЬ regardless of the ultimate realization of 6G, the stakeholder ecosystem has changed dramatically as the mobile landscape has evolved. The traditional mobile value chain has expanded to include new classes of operators, new vendor consortia, as well as new spectrum holders (with license conditions that may differ from the previous model of country‐wide coverage obligations), and has attracted a wide range of new vertical actors, largely drawn by the new capabilities 5G can unlock. 6G will likely lead to further expansion of this ecosystem.

Third, new political pressures and fault lines have emerged, which have already affected the standardization work of the 3rd Generation Partnership Project, commonly known as 3GPP. Fourth, while a broad community of solution providers has been envisaged, in practice, this has narrowed dramatically, leaving many operators dependent on just a handful of suppliers. Efforts are underway to change this, which could lead to deviation from the current standards path – accelerating or impeding progress toward 6G. Finally, 5G is enabled by an entirely new operating model that, in turn, could change the way in which stakeholders interact to define new standards in the future.

      This chapter explores the evolving landscape and considers possible future standardization models for 6G – and beyond – based on interviews with selected stakeholders and lessons drawn from the evolution of mobile network technology to date.

3.2 Standardization: A Long‐Term View

      How did we reach the point at which 5G could be realized, via what is effectively a single body that represents global mobile standards, and which has become the preeminent voice in the industry? Historically, this was not the case for each previous generation of mobile technology.

      There have been a number of successful standardization initiatives that have resulted in the release of each new generation of mobile technology – 2G, 3G, 4G, and, more recently, 5G. However, there has often been debate about how each such generation should be realized, which has led to variation in the implementation of some previous “Gs” and the emergence of parallel standards that have aimed to deliver the same outcome. In this section, we will briefly review current activities and explore previous approaches.

      For a number of years, each new “G” has begun with the release of what is known as an “International Mobile Telecommunications” (IMT) recommendation. IMTs are defined by the International Telecommunications Union (ITU), a specialist agency of the United Nations. It is important to note that an IMT is simply a recommendation. It does not define how it should be realized, but it does define expected performance levels:

      The term International Mobile Telecommunications (IMT) is the generic term used by the ITU community to designate broadband mobile systems. It encompasses IMT‐2000, IMT‐Advanced and IMT‐2020 collectively, [2].

      At the ITU, work is already underway toward 6G under the overall banner of IMT‐2030. Stakeholders such as solution vendors, operators, research institutions, and other agencies are collaborating to define 6G and what it may mean in practice. As part of these activities, FG‐30 (Focus Group on Technologies for Network 2030) is creating a definition of what a 6G network should deliver:

      The Focus Group intends to study the capabilities of networks for the year 2030 and beyond, when it is expected to support novel forward‐looking scenarios…The study aims to answer specific questions on what kinds of network architecture and the enabling mechanisms suitable for such novel scenarios [3].

      This will eventually result in a new IMT requirements definition, which will be available for the industry.

3.3 IMTs Have Driven Multiple Approaches to Previous Mobile Generations

      Previous generations of mobile technology have also been kick‐started by the agreement of a relevant IMT. While IMT‐2020 led to 5G and an agreed, unified approach spearheaded by the 3GPP, earlier IMTs have given rise to different approaches to achieve the same desired outcomes.

      For example, IMT‐Advanced provided requirements for the 4th generation of mobile technology (4G), but there were several approaches that could have met these. Long‐term evolution – otherwise known as “LTE” – was just one example; Mobile WiMAX and Ultra Mobile Broadband, among others, were, for several years, considered as viable alternatives, although only two remained as candidate systems – LTE and Mobile WiMAX [4]. Similarly, the earlier IMT‐2000 recommendations, which gave rise to 3G, also generated several different candidate solutions, some of which saw commercial operation.

      3GPP was originally founded in 1998, with the aim of bringing together a number of foundational partners to collaborate on common standards to meet the requirements of IMT‐2000 and the realization of what became known as 3G [5]. 3GPP based its efforts on the evolution of the existing GSM (the Global System for Mobile Communications) standards for 2G, originally driven through the European Telecommunications Standards Institute, or ETSI. The partnership agreement brought together organizations that had previously, either individually or via different collaboration groups, contributed to earlier generations of mobile technology.

      3GPP’s efforts resulted in a set of standards for 3G – the Universal Mobile Telecommunications System (UMTS) – whose work has ultimately led to today’s 5G. However, a parallel organization (3GPP2) shadowed the work of the original 3GPP during this period, considering the perspectives of a different group of stakeholders, some of which proposed alternative candidates for 3G, such as CDMA2000, to meet the same IMT‐2000 requirements.

      CDMA2000 was adopted in the United States, South Korea, Japan, China, and Canada, for example, but saw little deployment outside these countries, as most nations favored the UMTS standards defined by 3GPP. 3GPP2 subsequently pursued initiatives to create standards for the 4th generation of mobile; however, these met with little success, because, as far as IMT‐Advanced is concerned, LTE won the race and became the default commercial vehicle for 4G.

The alternatives also failed to gather significant commercial momentum (although some such as Mobile WiMAX did reach deployment in several countries) and, eventually, fell by the wayside. Different approaches to IMTs are illustrated in Figure 3.1.

Figure 3.1 IMTs and different generations of mobile network technology.

      As a result, 3GPP2 effectively ceased operations in around 2013 and is now a dormant organization. This latter point may be highly significant for the future, as we shall see.

      Even before this, while GSM had been promoted for 2G by ETSI, other approaches had been developed by alternative standards organizations, resulting in multiple 2G standards that enjoyed widespread adoption for a long period of time.

5G is thus something of an anomaly in the history of the mobile industry, as it represented a coordinated, single global approach to the realization of the IMT‐2020 demands. For each previous generation, there was not, at the outset, necessarily an obvious winner or a single unified approach. Will 6G see a return to such a situation, or will a global effort prevail? There are many reasons to think that 6G could well lead to fragmentation in mobile standardization. Why?

3.4 Stakeholder Ecosystem Fragmentation and Explosion

      3GPP is currently the main body pushing forward with the evolution of 5G standards, but it СКАЧАТЬ