Although the earliest 5G devices are not yet two years old, scientists began laying the next generation of cellular technologies – 6G – well before the launch of 5G networks worldwide. Nothing is set in stone, but the team of a telecommunications company Radiall advocates a radical change in the concept of ‘cellular’ infrastructure itself, with the use of many small, inexpensive antennas as an alternative to large antennas for 5G and older systems.
Historically, cellular or cell phones have used a dual hub and spoke system to connect devices to the network: the first hub is a central unit connected by fiber cables to multiple base station radio spokes, converting base stations into secondary wireless hubs connected to multiple spokes devices (e.g. ., phones). The geographical coverage area of each base station is a “cell” and neither the base stations nor the devices communicate with the base stations or cells outside that area – the phone switches from one place to another as it moves from place to place in the user’s pocket, hands or car.
Radiall is not the first to say that 6G can move to a networked infrastructure, but the company clearly understands how evolution can happen. The central node would still be connected to the base station radios, but the base stations would also be connected to each other, potentially using millimeter wave connectors not fiber. Instead of relying on a single base station for data, devices such as telephones could connect to two or more base stations simultaneously – a multimedia communication system that would create “microcells.” Visualize all your home and business Wi-Fi routers in the neighborhood, while offering wireless data connections to any nearby devices, and get the basic idea.
There are several potential benefits to a microelement system, but Radiall finds two that are particularly compelling: lower costs and higher energy efficiency. Unlike massive MIMO antenna arrays which are currently used to enable 5G connectivity, which is “extremely energy intensive” and expensive due to the placement of multiple antennas in one large tower to be broadcast over long distances, the microelement system will use several small distributed antennas to provide high coverage in practice. Over time, the result would be a “cell-free” network in which devices would benefit from whatever base stations were close by, rather than requiring a cellular tower.
Whether it is microcellular or non-cellular, the 6G system will have to process an almost inconceivable amount of data – artificial intelligence of the human brain caliber, holograms, digital twinsand other applications will require higher queue bandwidth than 5G still only offers, and faster throughout many more networked devices. Carriers may have chosen to use a combination of large and very small elements, but Radiall believes the use of multiple cells will be a “data capacity enhancer” when needed most.
In terms of components, Radiall says the move to a microcell system would allow cellular networks to use the most commonly available “building blocks”, including the same small and inexpensive transmit / receive modules already used in smartphones. However, the network will also need an interconnection to link and coordinate network activities, which will be increasingly distributed across points; whether that link will be partially wireless or fully wired is yet to come. Like others in the 6G research space, Radiall expects that terahertz radio spectrum will play a role in the next standard as 5G networks continue expand the use of millimeter waves, paving the way for some form of millimeter wave or near-terahertz spectrum to connect base stations to each other.
The main investigative work, Aggregated Massive Modular Paradigm: A 6G Telecom Infrastructure Vision was developed by the French team Radiall CEA-Leti 5G & Beyond Common Lab and is expected to appear in a future IEEE publication. Instead of judging his work as persuasive, the team describes it as a 6G “vision” and invites them to openly discuss these concepts.