November 2025

The vision for next-generation connectivity

Each new mobile network generation has brought greater data capacity and faster downloads, and in this respect 6G will be no different. But the vision for future connectivity goes far beyond this. Instead of networks focused on transferring information from one point to another, the aim is for a system that embeds digital communications into the fabric of all areas of society – bringing unprecedented levels of connectivity, resilience and innovation.

Such a communications landscape would enable a far greater variety of nodes to come online, for instance autonomous vehicles and intelligent ‘Internet of Things’ devices. This will allow a wealth of new technologies to become mainstream, from smart cities and virtual healthcare, to immersive digital environments and even applications we can’t yet foresee.

HASC is a partner in the Federated Telecoms Hubs (FTH), working alongside hubs such as TITAN, CHEDDAR, and JOINER, to address this ‘grand challenge’ of connectivity. Our particular focus is on the underlying physical connections within this fabric.

The technology behind future connectivity

Achieving next-generation technology will require integrating both existing communications infrastructure and new domains into a single coherent architecture. This is expected to include:

New frequency bands, including millimetre-wave (mmWave) and terahertz (THz) frequencies, enabling ultra-fast, short-range data transfer in dense environments.
Advanced optical communications, using both fibre-optic cables and free-space laser links. These will provide an ultra-high-capacity backbone for data-intensive applications, such as data centres.
Radio systems, which will continue to provide reliable, wide-area coverage and mobility.
Artificial intelligence (AI) and machine learning to manage complexity and optimise performance dynamically.

Together, these elements form the foundation of HASC’s work on future connectivity: a spectrum-agnostic, adaptive network fabric that unifies the best of wired and wireless systems. Ultimately, this will ensure that the UK’s communications infrastructure of tomorrow is not only faster, but more intelligent, efficient, and secure.

How is HASC helping to bring next-gen connectivity forward?

Delivering next-generation connectivity is a multifaceted challenge, with hurdles to overcome across technology, regulatory and policy domains. To address these, HASC is leading a holistic research portfolio, spanning Modelling and Measurement, Connectivity, Adaptivity, and Security. In particular, the hub stands out for its work in both optical and radio frequency communications, with a goal of generating insight on how we can unite wired and wireless domains.

Three particularly promising new technologies that HASC are investigating are:

Hollow-core optical fibre (HCF)

This next-generation fibre technology guides light through air rather than solid glass, which has the potential to substantially reduce the signal delay and distortion that limit today’s conventional single-mode fibres. HASC is investigating how these fibres can enable ultra-low-latency, high-bandwidth communication while also supporting new capabilities. In recent work, HASC researchers demonstrated that hollow-core and multicore fibres can carry both optical power and communications simultaneously, with the potential to improve the resilience of networks by providing ‘back up’ power.

Integrating sensing and communications

One of the emerging frontiers in Future Connectivity is the fusion of sensing and communications into a unified system sharing spectrum, hardware and signals. HASC researchers are making the measurements that underpin some of this work.

Quantum key distribution (QKD)

QKD can be used to improve network security by applying quantum mechanics to create cryptographic keys that are theoretically immune to eavesdropping. HASC researchers are investigating how to integrate QKD into both wired and wireless systems, to enable tamper-proof communications. In a recent study, they demonstrated secure data transmission using quantum encryption at speeds of up to 5 Mb/s over 25 kilometres of fibre. The system used an innovative approach where each receiver generated its own local reference signal, rather than sending one through the fibre – a design that makes the link far more secure against interception or tampering.

Other areas that HASC researchers are exploring include hybrid fibre–wireless links that combine the capacity of optical fibre with the flexibility of mmWave wireless; intelligent surfaces to boost the propagation of weakly-penetrating signals; optical wireless integration for high-capacity data transfer over short distances; and how AI can be applied to improve spectrum utilisation and network performance.

Breaking down barriers between academia, industry, and policy

The road to 6G and next-generation connectivity can be accelerated through close alignment between industry, policy professionals and academic researchers. A strong example is HASC partner Imperial College London co-chairing the European Telecommunications Standards Institute (ETSI)’s Industry Specification Group, collaborating with a range of companies including BBC and Viavi. This pre-standardisation forum focuses on developing future multiple access techniques for 6G standardisation.

Another case study is HASC’s collaboration with BT to develop Power-over-Fibre (PoF): a novel approach to delivering electrical power to communications equipment without relying on traditional copper cabling. As copper infrastructure is phased out in favour of all-fibre networks, the capability to support critical communications even during periods of local power outages is lost. PoF offers a promising alternative, enabling remote powering solutions in all-fibre communication systems. This work has already resulted in a series of demonstrations showing optical power delivery to remote equipment through the communication fibre, and several publications. The research is supported by BT, who developed the use cases motivating the investigation into PoF implementation solutions, sponsored a PhD studentship in this area, and loaned equipment for experimental network demonstrations.

IF YOU ARE INTERESTED IN FINDING OUT MORE ABOUT THIS TYPE OF RESEARCH JOIN US FOR THE FTH ADVANCED CONNECTIVITY SHOWCASE ON THE 1ST DECEMBER – REGISTER HERE

Delivering the vision

Next-generation connectivity represents a paradigm shift in how we understand, design, and experience communication. Instead of treating modes as separate technologies, these will be united into a single, intelligent system.

But there remain many unknowns. For instance, how can we diversify communications while reducing energy consumption and aligning with net zero targets? Can we leverage advances in quantum computing and integrate these into classical systems? How can we strengthen network security and resilience, for instance using new satellite capabilities?

These are difficult questions to address, and HASC is working together with our FTH partners to help answer them.

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Demand for wireless connectivity is rising exponentially. As requirements for speed, capacity and reliability grow, engineers and researchers are pushing beyond today’s mobile technologies to explore new frontiers in the electromagnetic spectrum. Two promising candidates for future wireless technologies are millimetre wave (mmWave) and the terahertz spectrum (THz). Both sit in the high-frequency wireless end of the spectrum and promise extraordinary capabilities, but they also bring challenges. Understanding the differences, and how they might work together, is a task that the Hub in All Spectrum Connectivity (HASC) is fully embracing.

What are mmWave & THz?

The electromagnetic spectrum is divided into frequency bands. The higher the frequency, the shorter the wavelength and the more data that can be carried, though this often comes with greater transmission challenges.

mmWave typically refers to frequencies between around 24 and 300 GHz, with wavelengths measuring between 1 and 10 mm. mmWave is already being commercially deployed in US 5G networks (with the UK moving towards implementation) and is a core part of the discussion around 6G.
THz generally refers to frequencies from 100 GHz up to 10 THz (10,000 GHz), with wavelengths between 3 mm and 30 µm. This range offers a very large bandwidth and high-capacity transmission, making it a key candidate for meeting the data demands of future network applications.

Since the ranges of mmWave and THz overlap, the boundaries between these are not always rigid, and their characteristics can sometimes blur.

The Similarities and Differences of mmWave & THz

As mmWave and THz are both high-frequency bands, they share many fundamental traits. These include:

High transmission loss: signals weaken quickly as they travel, which limits range and requires more transmitters or repeaters.
Poor penetration: walls, furniture and even human bodies can block or absorb the signal, making indoor coverage difficult.
Line-of-sight requirement: reliable links often need a clear path between the transmitter and receiver, as signals do not bend easily around obstacles.
Environmental sensitivity: conditions such as rain, humidity or atmospheric absorption can further reduce performance.

However, mmWave and THz also have key differences:

Data rates: whilst mmWave could deliver high-speed connectivity to modern networks, the capabilities of THz far exceed this, with the potential for ultra-high data rates exceeding 100 Gbit/second.
Propagation and loss: THz frequencies experience even higher propagation loss than mmWave. This means that while they can transmit vast amounts of data, their range is more limited.
Penetration: both mmWave and THz have significantly lower penetration than radio frequencies. However, whilst mmWave can penetrate certain materials such as glass with manageable loss, THz waves penetrate much more weakly and are mostly restricted to direct, unobstructed paths.

In short: mmWave can travel further, while the THz spectrum can deliver more data over shorter distances.

Use Cases: Today and Tomorrow

mmWave today: mmWave is already finding its place in commercial systems. Telecoms are integrating mmWave into mobile networks to boost capacity and deliver faster wireless experiences. For users, this means higher speeds in dense urban centres, stadiums or transport hubs where data demand is extremely high.

Emerging THz applications: THz is currently much less commercially developed, but global interest and research is expanding rapidly. Potentially, THz in telecommunications could:

Replace short stretches of fibre optic cable, especially in areas where fibre installation is impractical or costly (for instance, across rivers or challenging terrain), or where fibre networks have been damaged during disasters such as earthquakes.
Enable short-range high-speed comms in data centres, where stable, ultra-fast links are essential.
Support advanced applications such as holographic conferencing or virtual reality/ augmented reality environments.

The exciting part is how the two might work together: mmWave providing robust, wide-area coverage, while THz delivers extreme data rates for high-capacity, short-range applications.

Challenges and Innovation

The main challenge for both mmWave and THz is overcoming the physical limitations of high-frequency signals, in particular, the fact they lose power quickly and don’t diffract around or penetrate obstacles well. Researchers are tackling these hurdles on multiple fronts:

Device engineering: building transmitters and receivers capable of generating and handling such high frequencies efficiently.
Hybrid integration: combining THz wireless with existing optical fibre infrastructure to extend range and resilience.
Algorithms and adaptation: designing systems that adapt dynamically to user movement and channel conditions, ensuring reliable connections even in difficult environments.

HASC Research Spotlight

At HASC, researchers are working to address key unknowns about the use of mmWave and THz in telecommunications. This has included measuring and modelling the performance of mmWave signals and their ability to deliver ultra-reliable WiFi in factory settings, and demonstrating the generation of precise THz signals by combining two different laser signals (known as photo-mixing) a technique which could reduce the implementation and operation cost of a THz communications system.

A strong focus is the integration of THz wireless with fibre networks to create seamless, end-to-end systems. For example, HASC researchers at UCL, in conjunction with German colleagues, have demonstrated a fully-optoelectronic 300 GHz wireless link, achieving up to 180 Gbps over 1.5 metres. This was done by mixing optical signals in order to generate and receive THz wireless signals. Such experiments show how fibre and THz wireless can be combined, paving the way for networks that are faster, more flexible and more efficient.

The Future: Complement, Not Compete

Looking ahead, it is unlikely that the future will be one of mmWave vs THz; instead of competing, these will complement one another:

THz will excel in scenarios demanding extreme data rates over short distances, such as data centres or specialised industrial environments.
mmWave will continue to support mobile users who need higher speeds than 4G/5G mid-bands can provide, while accommodating movement and broader coverage.

Together, mmWave and THz will form part of a flexible, multi-band ecosystem. This is central to HASC’s vision: an integrated network of wired and wireless systems, dynamically adapting to user needs. Through our research programmes and by brokering exchange between academia, industry and policy, HASC is working to accelerate the transition to a high-frequency wireless future.