Even whilst 5G is still being rolled out worldwide, the groundwork for 6G is already being laid, with standards delivery expected around 2030. Data use worldwide is increasing exponentially (rising 15% in the UK between 2022 and 2023 alone), and this will only accelerate with the advent of emerging and future applications, such as autonomous vehicles, smart cities and immersive healthcare. This means that future telecommunications networks will need to deliver a step-change in capability, rather than incremental gains.

Introducing 6G is not only about faster downloads; the vision is for an extremely fast, ultra-reliable, low-latency, and intelligent communication fabric, achieving coverage everywhere and helping to close the digital divide. This network will also need the capacity to accommodate future 6G applications that demand extremely high data rates – and the terahertz (THz) spectrum is emerging as a promising candidate to extend standard technologies into new domains.

What is the THz Spectrum? 

The THz spectrum spans frequencies from around 0.1 THz (100 GHz) to 10 THz, with corresponding wavelengths from about 3 mm down to 0.03 mm – shorter than microwaves, longer than mid-IR/near-IR, and overlapping the far-infrared. What makes THz particularly appealing is the enormous amount of bandwidth available. This allows for ultra-high-speed connectivity, potentially supporting wireless data rates exceeding 100 Gbps – well beyond what is possible with 5G or even advanced mmWave.

Because of this, the THz band has become an active 6G research topic, with engineers and scientists worldwide exploring how it could reshape future mobile networks.

Why THz Spectrum for 6G? 

 The THz spectrum offers:

• Massive bandwidth: Enabling peak throughputs of 100 Gbps and beyond.
• Faster data transmission (lower latency): Because THz provides an exceptionally large bandwidth, each data symbol can be transmitted over a much shorter duration, reducing overall latency. In addition, the very high data rates available at THz frequencies make it possible to send information without compressing it first – avoiding the extra processing time needed for compression and decompression in lower-bandwidth systems.
• Closer integration with optical fibre: THz signals can be generated directly from optical signals by photomixing (where THz radiation is generated by combining two different laser signals on a high-speed optical detector). This makes it possible to create seamless hybrid fibre-wireless networks, combining the reach of optical fibre with the flexibility of wireless.
• Advanced sensing capabilities: Thanks to their very short wavelengths and unique interactions with different materials, THz signals can be used not just for data transfer but also for high-resolution imaging and sensing – enabling applications from gesture recognition to integrated communication-and-radar systems.

These qualities position THz as an enabler of the capabilities policymakers have identified for 6G: intelligence, sustainability, security and universal access.

Utilising the THz spectrum in 6G could also unlock new innovations, including:

• Immersive communication: Holographic conferencing, volumetric (3D) video and ultra-realistic augmented or virtual reality will demand ultra-high-speed connectivity with millisecond latency.
• Data centre connectivity: Short-range high-speed comms using THz links could replace some fibre interconnects, reducing cabling complexity and cost.
• Wireless backhaul: THz could provide fibre-like performance in places where laying fibre is impractical.
• ‘Smart’ applications and automation: By enabling high-resolution sensing, THz could support applications that include ‘Internet of Things,’ ‘smart’ factories and cities, and autonomous driving – areas that require precise motion tracking and/or machine coordination.
• Robotics: Highly-responsive connectivity and integrated sensing could enable advanced robotics, including for healthcare, surgery and industry.

Barriers and Challenges in THz

Despite its promise, THz communications face steep barriers:

• Severe propagation loss: THz signals attenuate rapidly in free space and are highly vulnerable to obstacles and environmental conditions.
• Short transmission ranges: Links are typically limited to tens of metres without special equipment.
• Regulatory uncertainty: Unlike microwaves and mmWave, which already have clearly defined and regulated spectrum allocations, the THz band still lacks globally agreed allocations for communications.
• Device engineering: Generating and detecting THz efficiently requires specialised photonic and electronic devices that are still under development.

HASC Research into THz 

To address these challenges, the Hub in All Spectrum Connectivity (HASC)’s THz research portfolio includes device development, optical-wireless integration and network modelling. Some highlights include:

• THz–Optical Convergence: UCL researchers in HASC, in collaboration with the University of Duisburg-Essen and ACST GmbH, recently demonstrated the conversion of optical fibre signals into THz wireless links, achieving data rates up to 180 Gbps. This shows how existing fibre infrastructure could be seamlessly extended into the THz domain.
• Dark fibre experiments: HASC is investigating the potential of the THz spectrum using the UK’s EPSRC-funded ‘dark fibre’ network. This gives researchers hundreds of kilometres of real-world fibre to test new ideas, such as carrying and regenerating THz signals over long distances to explore how to link high-speed fibre networks with future THz wireless systems.
• Device innovation: A promising technology is the UTC-PD (Uni-Travelling Carrier Photodiode), which converts optical signals into electrical / THz signals. HASC researchers are developing new ways of housing and integrating ultra-fast UTC-PDs, so they deliver more power, handle higher speeds and work more reliably in THz transmitters and receivers.

HASC’s broader portfolio includes advances to provide the underlying capabilities needed to reliably generate, stabilise and harness THz signals within future 6G systems. These include developing methods to create ultra-high-frequency signals by combining laser sources, and designing advanced THz receivers that detect high-frequency signals efficiently and are compact enough for easy integration into real-world systems. Together, these efforts lay the groundwork for turning the promise of THz into practical, everyday 6G connectivity.

6G and Beyond

As the 2030 target for standardising 6G rapidly approaches, the next few years will see THz research move from controlled experiments to field-ready prototypes, allowing researchers to assess how THz can fit into the next-generation communications network. If the attractive qualities of THz are to support the vision for a robust, flexible future telecommunications network, it is vital that the challenges of THz propagation, regulation and device design are addressed.

Ultimately, no single technology will deliver 6G: instead, it is likely this will dynamically integrate THz, mmWave, microwave and legacy frequencies to balance coverage, mobility and capacity. For industry professionals and academics alike, the message is clear: keep watching the terahertz 6G research space. The next generation of wireless is being built now, and the exciting capabilities of THz are starting to take shape.

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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.

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.

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Spectrum is the invisible infrastructure of our connected world. Every time we send a message, stream a video, or connect a device, we are relying on carefully managed slices of spectrum – the defined radio and optical frequencies through which wireless digital information flows. But this space is becoming increasingly crowded as our demand for mobile data grows year on year. By 2030, Ofcom has estimated that UK mobile data demand may be 7.5 to 52 times the level of 2021, and as high as 19 to 540 times by 2035. Managing the spectrum has therefore become both a highly complex and increasingly urgent challenge.

What Is Spectrum Management?

Although the electromagnetic spectrum is theoretically continuous, only certain ranges are practical for communications. Very low frequencies cannot carry high data rates, while extremely high frequencies – such as X-rays or gamma rays – are unsafe or impractical. This means that the usable portion (from 300 kHz to 300 GHz) is a finite resource.

Spectrum management is the coordinated allocation and management of usable frequencies to ensure wireless communication services can operate efficiently and without interfering with each other. Regulators (such as Ofcom for the UK) assign specific frequency bands for designated purposes – such as mobile phone networks, public safety functions, and satellite services. Telecommunication providers bid for frequency band licenses, then build infrastructure to deliver services. 

Why Spectrum Management Matters

Communications infrastructure is now as essential to our societies as electricity or water. In 2023, the UK Government described spectrum as a ‘critical national asset’, with ‘more efficient and intelligent use of spectrum’ a priority for continued growth across many sectors.

But just as demand for mobile data is rising exponentially, available spectrum in the most practical frequency range is becoming scarce. Usage is also becoming highly concentrated; for instance, most (around 80%) of wireless traffic now occurs indoors, carried over Wi-Fi or indoor mobile coverage. This places disproportionate pressure on lower frequency bands that propagate more easily through walls and other obstacles.

Meanwhile, emerging technologies, such as the future 6G, are pushing into higher frequency bands, including terahertz, which are technically more challenging and typically demand line-of-sight transmission. As more frequency bands come on board, this adds to the increasing complexity of the network, already convoluted by many legacy systems.

Energy consumption is also an increasing concern. If the UK is to achieve its Net Zero targets, reducing the energy footprint of data delivery is a key priority – however, improving energy-efficiency does not always align with achieving best spectral efficiency.

Meeting these challenges will require coordinated innovation that integrates technological advances with industry leadership and a supportive policy framework. HASC works at the intersection of these areas, forging towards a vision of seamless, energy-efficient spectrum management for tomorrow’s communication networks.

Addressing Congestion Through New Spectrum Access

Through our Connectivity work stream, led by University College London, HASC is investigating novel technologies that can use new regions of the spectrum, including terahertz and optical wireless domains. The optical spectrum is particularly attractive; unlike radio frequencies, much of the optical spectrum is not subject to regulatory licensing, and offers around 3,000 times more bandwidth. To tap into this opportunity, HASC researchers at Cambridge are pioneering Li-Fi: a high-speed wireless technology that uses light instead of radio waves. Experimental systems have achieved ultra-fast data transmission speeds of 100 Gbps; future work will build scalable systems that can support next-generation applications, and reduce pressure on the congested radio spectrum.

In the wired domain, a promising innovation is hollow-core fibres, where light travels through a hollow (air-filled) core instead of solid glass. These have the potential to transmit data with lower loss and latency, enabling higher speeds and energy efficiency in high-capacity settings such as data centres. Meanwhile HASC researchers at the University of Oxford are exploring how to link wired and wireless communication networks using light, by developing virtual fibres to provide high-speed wireless connectivity indoors. Data carried over fibres via light is then directed by a base station in the ceiling to travel wirelessly through free-space to a mobile terminal and back into a wired connection.

Improvements can also still be made in the radio frequency domain. Reassigning bandwidth in underutilised frequencies and decommissioning legacy networks, such as 2G, both offer ‘low-hanging fruit’ to free up capacity. A key focus for HASC, meanwhile, is exploring how we can ‘engineer’ the propagation environment using intelligent surfaces to overcome the natural travel limitations of higher-frequency signals, which could free up pressure on lower frequencies. This could include, for instance, engineered panels that guide radio signals more effectively through complex environments.

Managing Complexity with Adaptive and Multi-Band Systems

HASC’s Adaptivity programme, led by the University of Bristol, is addressing how we can efficiently manage the increasing heterogeneity of communications networks, with fibre, Wi-Fi, mobile, and optical systems operating in parallel. This work includes developing algorithms and AI-enabled control frameworks that can intelligently assess the most effective connectivity mode in real time, taking into account factors such as congestion, bandwidth availability, interference, and energy consumption.

A core element of this work is multi-band communication, where different portions of the spectrum (terahertz, radio frequency, and optical) are used simultaneously to enhance throughput and resilience. For instance, during emergencies or natural disasters, adaptive networks could quickly shift traffic from damaged wired infrastructure to wireless alternatives, maintaining critical communications when they are needed most.

This approach already shows promise in optical systems. Recent HASC research into multi-band optical transmission has demonstrated that by using extra spectrum beyond the traditional C-band (such as L- and S-bands) fibre networks could quadruple their capacity. Managing this expanded spectrum is technically challenging, but by applying deep reinforcement learning (a branch of AI that learns by trial and error) the research team reduced service blocking by up to 85% compared with conventional techniques, while keeping decision times practical.

Quantum and Spectrum Management

Communications systems are becoming increasingly complex and ensuring these remain secure is an ongoing challenge. Integrating new quantum technologies within the spectrum used by current systems, however, could provide enhanced security benefits. Through the Security challenge, led by the University of Cambridge, HASC researchers are investigating quantum key distribution (QKD) for both wired and wireless communication systems. QKDs use quantum mechanics to generate cryptographic keys that immediately alter their state in response to attempts to intercept or observe them. This makes them theoretically immune to eavesdropping, since this would alert the network to the presence of the breach.

Improved Energy Efficiency in Data Transport

Many of these technologies that HASC is exploring have the added potential benefit of reducing energy needs besides improving connectivity. Intelligent reflecting surfaces, for instance, reduce wasted transmitted power from poorly-propagating signals, whilst AI-enabled control frameworks could automatically select the most energy-efficient communication mode for a given situation. New types of optical fibre, meanwhile, could transmit much higher volumes of data, improving energy usage. In combination, these advances could enable future networks to deliver vastly more data without a proportional increase in energy use.

Looking to The Future

Ultimately, the goal of seamless, efficient spectrum management is inextricable from HASC’s vision of combining wired and wireless internet technologies into a single resource in order to deliver intelligent ‘all-spectrum’ end-to-end connectivity. Only then can we design future-proof networks that can intelligently adapt to meet the current and ever-evolving data demands of modern societies. By integrating advances across fibre, wireless, AI, and quantum, HASC is ensuring the UK remains at the forefront of research-led innovation to manage this unseen, yet essential asset.

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Here at HASC, modelling and measurement is a core element of our research – it is one of the four connectivity challenges we are exploring. In this post we explain modelling and measurement in more detail and discuss our approach to the challenge of combining wired and wireless internet technologies. Let’s get into it!

The Complexity of Modern Connectivity

The demands for connectivity are increasing exponentially. In today’s modern world, work has become borderless, mobile-first economies are booming and global audiences are becoming more diverse and more demanding than ever before. Our world is rapidly changing, as is our demand for faster, more agile connectivity. All this leads to greater complexity. As global connectivity expands and diversifies, communication networks need to keep up.

The Challenge of Managing Wired & Wireless Infrastructure

Traditionally, wired and wireless networks have been managed separately, with each being optimised individually for specific use cases. But with growing demand and ever more sophisticated requirements we must make better use of the spectrum as a whole.

To achieve the type of connectivity we need now, and, in the future, we must manage both resources as one unified entity. This means combining optical and radio frequency (RF) infrastructure… and this is where modelling can help.

What Is Modelling and Why Does It Matter?

To understand how we can improve connectivity, we first need the tools that help us test ideas safely and effectively. Modelling gives us exactly that. Modelling allows us to create digital representations of complex real-world networks and systems. These models help researchers and engineers simulate different scenarios, test new ideas, and predict how networks will behave under changing conditions. And all this without the cost or disruption of real-world trials. In the context of wired and wireless systems, modelling is crucial to understanding the interplay between technologies and identifying smarter, and sometimes more sustainable ways to deliver high-performance connectivity.

Analytical and Simulation-based Modelling Explained

Did you know there are different types of modelling? Here, we explain the differences between ‘analytical’ and ‘simulation-based’ modelling.

Analytical modelling

Analytical modelling uses maths and logic to describe how a system should behave, often resulting in equations that reveal core principles, such as how signals propagate (how they travel from transmitter to receiver in different environmental conditions).

Simulation-based modelling

Simulation-based modelling, by contrast, involves running virtual experiments using software. It allows us to test real-world conditions, explore ‘what if’ scenarios by adding new variables, and validate the ideas developed during the analytical stage.

HASC’s Approach to All Spectrum Connectivity & Modelling

At HASC, we’re not studying networks in ‘silos’, we’re building models that treat wired (optical/fibre) and wireless (radio frequency) infrastructure as one interconnected system. This approach allows us to explore how these technologies can best work together. We use a framework that includes both analytical and simulation-based modelling to illustrate and better understand how to optimise different combinations of the spectrum. We are experimenting with how both wired and wireless channels can be used together across various applications and in many different environments.

A Holistic Network Model

This unified approach will allow us to:

• Capture the interactions between different network layers, network types, and technologies.
• Observe multiple variables across both systems, such as bandwidth, latency, energy use, traffic load, and environmental factors.
• Re-create real-world complexity, rather than assuming ideal or simplified conditions for just one part of the network.

In new and emerging environments like smart cities, connected transport, or connected healthcare both types of connectivity need to be used together – often dynamically.

A Look Inside A HASC Modelling Project

One of the most ambitious modelling projects underway at HASC focuses on understanding how signals travel at ultra-high frequencies like mmWave, THz, and even light-based wireless. Here’s how that work is unfolding.

Enhanced channel measurement and modelling

mmWave, THz, Optical channel measurements and modelling

Project Led by Simon Cotton, QUB

This project supports the development of next-generation wireless technologies, such as 6G, by advancing our understanding of how high-frequency signals behave in real-world environments.