Just when we thought that the hype around 5G has come to an end, a new spotlight is shed on the next network generation. As much as 5G is powerful, the capabilities of 6G will be unimaginable. Even though 5G still hasn’t materialized all over the world, however, getting ready to 6G is now a reality, even if it might seem far-fetched at this stage.
The new target year in the telecoms industry is 2030. Visions have been elaborated to meet a set of goals by this deadline, with 6G being one of them. Telecom vendors have initiated their 6G research efforts a few years ago, long before the sixth network generation drove conversation, in a bid to lead the race to 6G and deploy it by 2030.
Characteristics
According to the ITU Journal on Future and Evolving Technologies, Volume 2 (2021), Issue 6, 6G will deliver throughput/data rate up to 1 Tbit s−1 and user-experienced data rate of 1 Gbit s−1, which is ten times the one targeted by 5G. It will provide end‐to‐end latency less than 1 ms and an ’over-the-air’ latency of 10 −100 µs with mobility up to 1000 km h−1 with very broad bandwidth with frequencies reaching 1 −3 THz.
The vision of 6G has also been enhancing the idea of ’ecosystem’ of networks (or network of networks), preliminarily started with 5G. This has been making 6G closer and closer to the concept of the ’Web of Everything Everywhere’.
Every new network generation brings along a new experience. 2G and 3G brought voice and text that enabled human-to-human communication. 4G drove data consumption and traffic while 5G unleashed new use cases and allowed users to benefit from a plethora of revolutionary technologies such as IoT. In the 6G era, the digital, physical and human world will seamlessly fuse to trigger extrasensory experiences. 6G will serve as a distributed neural network that provides communication links to fuse the physical, cyber, and biological worlds, truly ushering in an era in which everything will be sensed and connected.
6G will build on top of 5G in terms of many of the technological and use case aspects, driving their adoption at scale through optimization and cost-reduction. At the same time, 6G will enable new use cases. In 2030 and beyond, augmented reality and artificial intelligence will shape our lives. With 6G, ultra-high speed and ultra-reliable wireless connections will allow sensing and AI to flourish.
Digital twins will be found not only in factories but also in wide area networks of cities and will operate at a larger scale with 6G deployed.
The pillars of 6G
Artificial intelligence will be the main pillar of 6G. Each 6G network element will natively integrate communication, computing, and sensing capabilities, facilitating the evolution from centralized intelligence in the cloud to ubiquitous intelligence on deep edges.
Wireless sensing capabilities will be required to explore the physical world through radio wave transmission, echo, reflection, and scattering. 6G will feature this capability that will enable intelligence. Such a mode of sensing can help create a “mirror” or digital twin of the physical world in combination with other sensing modalities, thereby extending our senses to every point the network touches. Combining this information with AI/ML will provide new insights from the physical world, making the network more cognitive.
6G will also allow the integration of terrestrial and non-terrestrial networks into one system to provide uninterrupted high-quality services to users everywhere.
Moreover, security and trust are a fundamental element in 6G. According to a white paper by Ericsson, the four important building blocks for trustworthy systems are the use of confidential computing solutions, secure identities and protocols, service availability, and security assurance and defense. Huawei states that data, as well as the knowledge and intelligence derived from it, is the driving force behind 6G network architecture redesign, wherein new features will be developed to enable E2E native trustworthiness. These include new data governance architectures supporting data compliance and monetization, as well as advanced privacy protection and quantum attack defense technologies.
6G networks will also aim to improve energy efficiency 100 times across the network and limit energy consumption of ICT infrastructure and terminals while also ensuring optimal service performance and experience. Sustainability will be at the heart of the sixth generation network.
How will 6G change the world?
6G will be an extension of 5G, with an even more enhanced and immersive experience. G will build on top of 5G in terms of many of the technological and use case aspects, driving their adoption at scale through optimization and cost-reduction. At the same time, 6G will enable new use cases.
Digital twin models, already being used with 5G, will operate at a much larger scale with 6G. They will be found not only in factories but also in wide area networks of cities and digital twins of humans will have a major impact on the network architecture.
A new man-machine interface will emerge. Smartphones will remain a key device, however typing will gradually be replaced by gesture and voice control and wearables will gain even more ground.
Enormous capacity demands require new spectrum
The evolution into the next network generation has always required a transition into a higher frequency band. The move from 3G to 4G grew carrier size from 5 MHz to 20 MHz, while the transition from 4G to 5G saw carrier bandwidth grow from 20 MHz to 100 MHz. A blog article by Bell Labs expects that with 6G spectral bandwidths will increase once again, reaching 400 MHz, greatly increasing the baseline capacity of a single cell.
Clearing up new spectrum will be necessary to unleash 6G’s capabilities and use cases. Bell Labs expects that new spectrum bands between 7 GHz and 20 GHz will open up for 6G use, which will provide the necessary bandwidth to create these new high-capacity carriers.
Furthermore, new bands will be identified for mobile use by governments and regulators are looking at the 470-694 MHz band as a means for providing broad coverage in rural and remote regions. The low frequencies in this band mean signals propagate much further, extending the network’s reach. Sub-THz bands beyond 90 GHz might also come into use, which could supply extremely high peak data rates for the most bandwidth-intensive applications as well as connect highly dense sensing networks.
However, new spectrum might not be enough. Multiple-input multiple output (MIMO) techniques were deployed with 4G and 5G to improve spectral efficiency of wide area cells. 4G uses 2x2MIMO and 4x4MIMO while 5G benefits from massive MIMO using around 200 antenna elements and up to 64 transceivers. 6G may support on the order of 1024 antenna elements in the new mid-bands.
Challenges
Ensuring coverage across the whole world remains a challenge, especially that remote areas still lack access to connectivity. The main mission of 6G is to make this happen. 6G allows space-earth integration that can pave the way for a 100% coverage that can reach remote areas.
Another challenge resides at the level of bandwidth. It is estimated that the terahertz in 6G era will have the same problems as the millimeter wave today: weak coverage capability, high cost of deploying network, premature ecosystem of terminals, among others.
Security is also an important issue that 6G should address. Given the need for trustworthy networks, especially in light of new use cases, securing 6G networks is undeniably a top priority.
Operators are called to deploy low-carbon and energy-saving networks that is why green and sustainable development is the core requirement and ultimate goal of network and terminal designs in 6G.
Is it too soon to talk about 6G?
2030 might seem a long way to go, but when it comes to technology, it’s never too soon. Research on 6G started even before 5G was deployed. The ITU is planning to issue its IMT-2030 vision document in 2023, and the 3GPP timeline calls for the studies on 6G to start in 2024, so 6G doesn’t sound so far into the future anymore.
Telecom vendors, operators and research bodies are well involved in 6G studies to better define the network generation. Work done in the framework of the race to 5G is a lesson that all industry experts should learn from in order not to replicate the mistakes made with 5G and avoid the obstacles that impacted its deployment.
One key area that should be addressed before 6G launches is the digital divide that has further widened with 5G. While 6G promises 100% coverage, a significant number of countries still lack 5G network coverage. Expediting 5G networks deployment across all regions should go in tandem with 6G research to be able to achieve the sought objectives of 6G.