SoftBank Corp recently announced its 6G (known as “Beyond 5G” in Japan) concept and the challenges that need to be overcome to make the concept a reality.
On top of enhancing 5G’s features that include ultra-high-speeds, ultra-low latency, and massive device connectivity, 6G is expected to bring new technological innovations, including high reliability and improved energy efficiency. To provide a network infrastructure needed for the 6G era society, SoftBank is taking up the challenge of resolving numerous issues in different areas. Working toward that goal, SoftBank’s current initiatives include expanding into areas where wireless technologies can be utilized for purposes other than telecommunications, such as evolving network architectures where AI can function, ensuring high levels of resiliency so that all businesses can utilize these advancements with peace of mind, and contributing to the realization of a carbon-free society.
Ryuji Wakikawa, SoftBank Corp. Vice President and Head of the Advanced Technology Division, commented as follows:
- Up to 4G, mobile networks were designed for smartphone usage. After 5G, the advent of 6G will transform mobile networks into network infrastructure that will support the digitalization of all industries. With 6G, every business across Japan will be built on the foundation of mobile networks, just as the Internet became the sole common basic infrastructure for online communications around the world.
- The Internet will be utilized to build a virtual digital space, with mobile networks connecting base stations and devices. In this way, digital and physical spaces will be connected in real time. What is predicted and judged in the virtual space using AI will be fed back to the physical space with ultra-low latency. Not only will 6G networks serve as communication networks; they will also evolve into computers that support an AI society. Edge computers will be deployed everywhere in Japan, and these computers will be capable of AI and other types of server processing to disperse computing. These computers will establish a high-quality, end-to-end communications environment connected to networks in highly sophisticated ways. If AI is the trigger for the next Industrial Revolution, 6G will be the telecommunications infrastructure that makes it happen.
- SoftBank started research and development of potential 6G technologies such as High Altitude Platform Stations (HAPS) and terahertz communication back in 2017. By flying base stations in the stratosphere, HAPS systems are capable of receiving and transmitting radio waves over an area stretching as far as 200km in diameter, as well as into the airspace above. As such, HAPS is expected to be a key technology for expanding communication area coverage. We have already successfully completed a communications test in the stratosphere, spearheaded initiatives to standardize HAPS frequency bands, established a global industry alliance, among other achievements. Furthermore, as part of our efforts to expand frequency usage, we are working on the terahertz range beyond millimeter-wave with the aim of applying these frequencies for telecommunications. New possibilities will open for wireless networks to be used at data centers, such as wireless communications between racks and servers, when we achieve telecommunications faster than fiber-optic cables and reach communication speeds in excess of several hundreds of gigabytes per second.
- We have been working on various research and development projects, always taking the application of mobile communications into consideration while doing so. We are now unveiling some of these technologies for the first time. 6G is playing a key role in SoftBank’s digital platform strategy, and it will support a variety of businesses as a common basic infrastructure, help AI technologies to blossom through the creation of “digital twins,” and make it possible to realize fully customizable communications networks and computer resources. Guided by our corporate philosophy, “Information Revolution – Happiness for everyone,” SoftBank is taking on the challenges to make 6G a reality with the aim of realizing the complete digitalization in Japan.
12 Challenges for 6G
(1) SLA vs. “best-effort”
Until now, services provided on mobile networks that connect smartphones to the Internet have been on a “best-effort” basis because of the nature of the Internet protocol (IP). For example, small network delays or packet loss were unlikely to inconvenience people’s daily lives, such as online shopping and video streaming. In the future, however, 6G mobile networks will underpin network infrastructure that supports a variety of industries. SoftBank will accommodate complete end-to-end communication for customers with appropriate Service Level Agreements (SLA) in its network by leveraging Mobile Edge Computing (MEC) and network slicing.
(2) API-driven network customization
There is no doubt that the Internet has continued to evolve systems and protocols because of its openness. On the other hand, the evolution of mobile networks was limited due to proprietary technologies and a closed culture for a long time. For mobile networks to be a fundamental infrastructure for various industries, they need to be capable of supporting customization and dynamic configuration on the fly. SoftBank will provide more convenient services for customers by incorporating RESTful (Representational State Transfer) application programming interfaces (APIs) to customize and configure its network for customer needs.
(3) AI networks
AI technologies are now applied to more areas than before, including for the detection of objects using image-recognition technologies, voice recognition/translation, and network optimization/automation operations. However, AI engines require a lot of data and computational resources. The AI engines could be deployed over networks with various rich data handling and unlimited computational resources instead of having them in devices. To maximize the power of network-based AI, high-speed and low-latency networks are required. By distributing GPUs as well as servers across mobile networks, it will be possible to provide low-cost, high-quality networks and AI services. These GPU resources could also be used to automate SoftBank’s network operations with AI intelligence as well. SoftBank has been conducting technological verifications of virtual base stations equipped with GPUs since 2019. SoftBank’s network will be adjusted to network traffic patterns, customer behavior, and network demands automatically by AI.
(4) 100% coverage
6G networks will require the elimination of dead spots where people live and total coverage around the globe. SoftBank aims to solve these challenges by offering Non-Terrestrial Network (NTN) solutions that utilize HAPS and Low Earth Orbit (LEO) and Geosynchronous Earth Orbiting (GEO) satellites. This will enable SoftBank to offer Internet services to more than three billion people around the world who are currently unable to access the Internet. It will also allow mobile network access at sea, in mountainous areas and in the upper atmosphere, where the installation of base stations has been impossible to date. As the underlying infrastructure, 6G networks will pave the way for new industries that enable autonomous driving, flying taxis and drone-based delivery services, among others.
(5) Area expansion by HAPS
HAPSMobile Inc., a subsidiary of SoftBank, has been developing stratospheric telecommunication platform systems since 2017. In 2020, the company successfully demonstrated stratospheric flight and long-term evolution (LTE) communications from the stratosphere in New Mexico, USA. “Sunglider,” an unmanned aircraft system equipped with solar panels, was used as the stratospheric communications platform for the test. The successful test proved the feasibility of SoftBank’s High Altitude Platform Station (HAPS) technology. Utilizing the large amount of data obtained from the test flight, SoftBank is developing aircraft systems and wireless equipment with a view to commercialization and preparing to meet regulatory requirements.
(6) Beyond millimeter-wave: terahertz and optical communication
5G technologies made it possible to use millimeter-wave frequencies that had remained an untapped resource in mobile communications previously. For 6G, the terahertz range, frequencies higher than millimeter-wave, such as terahertz and optical range, will be exploited to construct networks that operate at ten times the speed of their 5G counterparts. Frequencies ranging from 100GHz to 10THz are generally regarded as being in the terahertz range. The World Radiocommunication Conference 2019 (WRC-19) set aside a total of 137GHz for telecommunications use among frequencies above 275GHz that had never been allocated previously. By exploiting this vast range of frequencies for mobile communications, SoftBank’s aim is to achieve even faster speeds and ever-larger volume communications.
(7) Sensing and positioning
Mobile operators have utilized radio spectrum just for telecommunications purposes until now. However, 6G can be used not only for communication but also for sensing and positioning simultaneously. For example, a technology using Wi-Fi to identify the location of a person indoors is already in practical use. In addition, Bluetooth® is now being used to track positional data. In the coming 6G era, in addition to communications, SoftBank will look to offer communication, sensing and tracking services with its base stations.
(8) Charging / Power supply
For devices such as smartphones, Qi-standard contactless charging technologies are widely used. However, this method has a drawback, which is its inability to charge or supply power when the device is placed even a short distance from the charger or power source. 6G will drastically change the ways of charging batteries and daily charging routines. To realize that future, SoftBank’s R&D efforts will focus on wireless charging/power-supply technologies for battery-powered devices such as IoT sensors, smart meters, audio headsets, mouse and keyboards.
(9) Maximum frequency utilization and efficiency
Until now, frequencies have been allocated based on the purposes of the applications that each service provider used exclusively. However, by applying Internet protocol (IP) technologies to wireless zones, multiple providers should be able to share bandwidths available at certain times and in certain places. Multiplexing technologies, including massive multiple input/multiple output (MIMO) and dynamic spectrum sharing (DSS), are already established. By further advancing these technologies and others, our aim is to utilize frequencies more effectively.
(10) Network security
As their development gathers momentum, it is said that quantum computers may enter practical use by 2030. When this happens, it will become possible to decipher the RSA codes*1 currently used for Internet encryption, which could make networks vulnerable to communication content theft. In order to protect all businesses built on communications infrastructure, SoftBank is working on the technological verification of various systems, such as post-quantum cryptography (PQC) and quantum key distribution (QKD). By advancing these technologies, our aim is to build ultra-safe networks.
(11) Resilience, Redundancy, Recovery
With the rollout of 5G, mobile networks will play an ever-increasing role in network infrastructure. Accordingly, networks need to continue to function, even under circumstances where a communications failure occurs. To this end, SoftBank is reviewing traditional network architectures and working to build fault-resistant networks. At the same time, SoftBank is developing technologies that will enable networks to maintain services anytime a failure occurs.
(12) Carbon-free and Net-zero
Large-volume data obtained from sensors and devices, as well as data processing by all types of computers, will enable the 24/7 monitoring and observation of CO2 emissions. This will make a significant contribution to achieving net-zero greenhouse gas emissions. On the other hand, constant monitoring using sensors could raise privacy issues that need to be solved, including the handling of personal information and data security. In parallel, SoftBank is aiming to achieve carbon-neutral operation of base stations. At present, laws require the installation of batteries for emergency power supply at base stations to sustain network services at the time of a disaster. It is possible to curb greenhouse gas emissions by utilizing these batteries on a routine basis, as well as by operating the base stations at night using electricity that was generated and stored during daytime hours. Furthermore, by controlling the operation of base stations in real-time in accordance with communications volume, power consumption can be minimized. SoftBank is carrying out R&D to realize carbon-free base stations.
SoftBank also unveiled two initiatives as specific examples of its undertakings to realize 6G services.
This first one is an R&D project involving “Moving Terahertz” for smartphones. This initiative focuses on expanding frequency ranges that will enable SoftBank to provide commercial services using the terahertz band for mobile communications. The exhibit introduces a system based on the concept of moving terahertz, publicly demonstrating its application via real-time video transmission utilizing OFDM*2 in a mobile communications system.
The second involves SoftBank’s initiatives to establish HAPS technologies, where communications equipment (a payload) that was used in a stratospheric flight test is displayed. Also on display is a cylinder antenna currently under development and a demonstration of rotating connector technology. Both technologies are essential for realizing footprint fixation technologies to control communications areas, which will be necessary to provide stable communication services with HAPS.
- *1Rivest-Shamir-Adleman (RSA) codes are public key encryption based on prime factor decomposition problems that are difficult to decipher and currently used widely on the Internet.
- *2Orthogonal frequency division multiplexing (OFDM) is a modulation technique used in terrestrial digital broadcasting and other applications.
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