As the demand for mobile connectivity continues to rise — both in terms of user densities and data throughput — the energy consumption of next-generation mobile networks is on the increase is only expected to become even larger in 6G. This trend is further intensified by the shift to higher-frequency bands and the deployment of a larger number of physically-smaller and lower geographical coverage base stations. In this paper, we propose a set of novel approaches, developed within the CHIST-ERA SAMBAS project (“Sustainable and Adaptive Ultra-High Capacity Micro Base Stations”), to improve energy efficiency in next-generation mobile networks. On the one hand, we aim to reduce the overall energy consumption of mobile networking; on the other, we explore the substitution of a significant portion of energy demand with green, locally harvested renewables — either used instantly or stored for later use - made practicable by the powering requirements of smaller yet still high-performance micro-base stations. We also introduce models, strategies, and methods, accompanied by a comprehensive assessment of their performance and feasibility.

This paper presents a feasibility study aimed at understanding centralized radio access network (C-RAN) deployments based on incumbent distributed radio access network (D-RAN) topologies. A model is derived to allow realistic latency characteristics to be calculated for fronthaul connectivity between existing cell sites and transport network aggregation nodes (hubs) suitable for baseband centralization. Analysis has demonstrated that as much as 96% of urban cell site neighbor pairs could satisfy C-RAN fronthaul latency budgets if baseband processing were to be centralized at the local transport hub and 91% when centralized at the regional transport hub using single mode fiber. Findings suggest that the feasibility of advanced coordinated transmission schemes between such pairings could be realized based on existing real-world fiber deployment topologies. Furthermore, the proportion of sites that could support C-RAN requirements could be increased further to 97% when aggregated at local transport hubs and 95% at regional hubs where hollow core fiber transport solutions are employed.

Purpose in systems is considered to be beyond the purview of science, since it is thought to be intrinsically personal. However, just as Claude Shannon was able to define an impersonal measure of information, so we formally define the (impersonal) ‘entropic purpose’ of an information system (using the theoretical apparatus of Quantitative Geometrical Thermodynamics) as the line integral of an entropic “purposive” Lagrangian defined in hyperbolic space across the complex temporal plane. We verify that this Lagrangian is well-formed: it has the appropriate variational (Euler-Lagrange) behaviour. We also discuss the teleological characteristics of such variational behaviour (featuring both thermodynamically reversible and irreversible temporal measures), so that a “Principle of Least (entropic) Purpose” can be adduced for any information-producing system. We show that entropic purpose is (approximately) identified with the information created by the system: an empirically measurable quantity. Exploiting the relationship between the entropy production of a system and its energy Hamiltonian, we also show how Landauer’s principle also applies to the creation of information; any purposive system that creates information will also dissipate energy. Finally, we discuss how ‘entropic purpose’ might be applied in artificial intelligence contexts (where degrees of system ‘aliveness’ need to be assessed), and in cybersecurity (where this metric for ‘entropic purpose’ might be exploited to help distinguish between people and bots).

This article presents a mobile network deployment analysis aimed at understanding the use of high-frequency wireless fronthaul links to realize dense cell network architectures. A high-resolution digital twin model is built based on real-world datasets to identify line-of-sight (LoS) propagation paths between existing macrocell rooftop sites and lamp post infrastructure locations suitable for new street-level cell sites. The resulting LoS path topology is used to simulate wireless fronthaul links based on industry-standardized fronthaul interfaces across the urban environment. In considering the stringent fronthaul interface requirements for a representative 5G radio configuration, the suitability of emerging mmWave and sub-THz transport bands between 71.124 and 174.8 GHz to fulfill the wireless fronthaul-centralized RAN (C-RAN) deployment is analyzed. Findings in this work have demonstrated that with the right combination of fronthaul interface and spectrum band up to 73% of new street-level cell sites in a dense deployment could be built using a wireless fronthaul transport solution.

The next generation of railway customer-oriented services are expected to generate a large volume of data ( $\approx$ 10s of TB). As a result, passengers' applications, safety, security, and Internet-on-Board (IoB) sensors challenge current Train Communication Networks. With the present Ethernet Train Backbone (ETB) specification of just 100 Mbit/s in total, railway passenger services will not support intelligent, seamlessly connected and mobile media on-board trains. In this paper, we propose a novel ETB design with experimental results demonstrating end-to-end 10 Gbit/s and 40 Gbit/s throughput results over existing conducting media on commercial railway carriages. This is equivalent to 100 Mbit/s per user on real-world railway rolling stock and shows that standard RailCat 5e cabling and new rail-approved 10 Gbit/s ETB active nodes (switches) fully support emerging trends and future-proof ETB configurations.

The migration of professional audio systems towards Ethernet-based networking allows optimisation software to maximise key performance indicators (KPIs) such as the power required for particular applications. In this study, we focus on minimising peak power requirements by the use of supercapacitors (SCs) for demand smoothing with Class D audio amplification of at least 600 W root mean square (rms) output. Depending on the content, a 600 W maximum r.m.s output music programme is shown to draw just 60 W (10% of peak rms) on average. Our studies used music programme statistical analysis and probability theory, which enabled the minimum value of SC for a predetermined voltage drop to be found exactly and hence minimise costs/size requirements. The use of energy storage in audio (and other contexts) is not new of course, but we believe the probabilistic calculation and use of unprecedented SC reservoir capacitance values is original. This power averaging technique then allows Power-over-Ethernet (PoE) to be used, particularly the IEEE802.3 bt type 4 variant and AES67 Ethernet over powerline. As commercial PoE systems are now available for this standard, we have constructed a complete 600 W r.m.s class D sound system which has type 4 PoE as its sole power input. Again, PoE sound systems are not new but the extension to very high powers has not been reported to the best of our knowledge. In the powerline context, we describe a first-of-its-kind, outdoor venue, 5000 W peak rms, Class D audio system with > 1 km of standard 5 A mains cable, AES67 audio transport over powerline and lithium-ion energy storage at the amplifier location. An added benefit is that solar assistance can be used.

To date the evolution from traditional distributed radio access networks (D-RAN) towards fronthaul oriented centralized (C-RAN) architectures has imposed significant challenges for the underlying transport network. The processing and coordination benefits anticipated in C-RAN are generally underpinned with the assumption of a full fiber transport network capable of meeting the demanding performance criteria of fronthaul transport. Recent advances in Ethernet based fronthaul interfaces together with exploration of new mmWave and sub-THz spectrum bands present an opportunity for wireless solutions to also realize these fronthaul transport requirements. In this work, the requirements for promising new Ethernet based fronthaul interfaces are explored. These requirements are assessed against the measured capabilities of a state-of-the-art E-band (71-86 GHz) wireless transport solution. The experimental results are then used to forecast the performance expectations of future higher bandwidth systems operating above 100 GHz. A dimensioning and link budget analysis is performed for the various candidate spectrum bands and fronthaul interfaces to highlight the viability of fronthaul delivered over wireless transport. Finding show that transport solutions operating at mmWave and sub-THz frequencies are able to support the performance requirements of newly standardized fronthaul interface splits and as such present an opportunity to utilize wireless fronthaul transport in C-RAN architectures where fiber cannot otherwise be supported. Furthermore, analysis demonstrates that the hop lengths possible for 5G small cell configurations are well aligned with the expected inter-site distances of future dense urban cell deployments making wireless fronthaul a promising concept for realizing future C-RAN based cell densification.

The application of wireless backhaul is widely adopted in commercial mobile networks as a cost effective alternative to fibre. However, the practical use of wireless transport to support new cloud RAN architectures is not well studied. This paper presents proof-of-concept results which extend evolving Ethernet based mobile fronthaul concepts to wireless transport solutions. The theoretical performance criteria of the 3GPP option 8 functional split is derived and experimentally verified using an Open Air Interface (OAI) base station. Wireless fronthaul performance is assessed over an Ethernet-based E-band (71-86 GHz) mmWave radio link. Experimental measurements demonstrate the viability of existing mmWave wireless transport solutions to meet the performance requirements of the most challenging Ethernet based 3GPP option 8 fronthaul interface. Findings also suggest that further advances in standardisation of alternative functional split interfaces as well as higher capacity wireless transport spectrum such as D-band (130-174.8 GHz) could further support scalable cloud RAN deployments of the future.

In this paper we present a new line-of-sight probability model for the urban micro cellular deployment scenario. This study utilises a high resolution 3D model of central London to conduct large scale ray-tracing of direct propagation paths between neighbouring lamp posts. These serve as a representation of mmWave self-backhauling small cells such as 3GPP integrated access and backhaul nodes. The statistical properties of the propagation paths are assessed against recognised line-of-sight probability models as a function of the distance between transmitter and receiver. Contributions as outlined in this paper have application in analytical studies aiming to understand the statistical characteristics of unobstructed high frequency ‘access’ links between microcell sites and end users as well as ‘transport’ backhaul links between neighbouring microcell sites.

This paper presents a mobile network deployment analysis aimed at understanding the potential use of high frequency (mmWave) wireless ‘x-haul’ to deploy new urban street level micro cell sites. A highly detailed 3D environmental model of central London is constructed and the line-of-sight (LOS) propagation paths between real rooftop cell sites and street level lamp posts calculated in order to simulate all of the potential wireless x-haul paths across the urban environment. Analysis is subsequently carried out to quantify the number of new lamp post mounted micro cell base stations that could be x-hauled using a multi-hop wireless transport solution such as 3GPP Integrated Access and Backhaul (IAB). Results highlight the viability of mmWave wireless transport in real urban environments. Findings also outline the fundamental requirements that a multi-hop wireless transport solution must meet in order to maximise its potential as a lower cost and time-to-market alternative to a fully fibred network.

Over the years, effective transmission of radio signals on trains and moving vehicles alike has been difficult owing to non-line-of-sight (NLOS) communications. This work is centered on the use of passive reflectors employing different obstacles to improve radio transmission for the study of the NLOS communications in the 60 GHz mmWave for indoor scenarios. In this study, we compute the gain achieved in the transmission link using two commercial-off-the-shelf (COTS) antennas by way of analytical and beam tracing for the end-to-end transmissions. In particular, we demonstrated a systematic guide for the end-to-end received power in an NLOS situation using six different signal transmission obstacles. For a given geometry of the obstacles, we showed that the reflected received throughput for the NLOS link followed a similar pattern in comparison to the line-of-sight (LOS) link received throughput. We used the 5G fixed wireless access (FWA) platform as one of the most dynamic and fast-growing segments of the 5G network where the use of antennas with relays can overcome the limitations of NLOS to provide the needed connectivity.

In this article, we present a novel analytical approach used to derive a new multiscenario line-of-sight (LOS) probability model for cellular network deployments in the U.K. The approach considers the use of lamp post databases as statistically representative geospatial data points for the evaluation of LOS likelihood from macrocellular base stations. Crucially, the proposed model is built on a high-resolution (0.25–1 m) 3-D digital surface model underpinned by real network and environmental datasets and validated with supporting field measurements. This work unifies all common cell site classification types: urban, suburban, and rural into a single 3-D LOS statistical probability model while also addressing the influence of endpoint height properties up to 10 m. The contributions outlined in this article have applications in statistical path loss modeling and coverage/outage probability. They also have direct application in deployment modeling of millimeter-wave (mmWave) mobile access networks (24.25–52.6 GHz) and wireless x-haul transport networks (71–174.8 GHz).

The line-of-sight (LOS) probability model is a fundamental tool in evaluating high frequency (mmWave) mobile network deployments. This paper utilises a large scale 1875 sq km, high resolution environmental model of representative UK cities to analyse the statistical LOS properties of urban macro (UMa) base stations. The digital environment results are used to evaluate the accuracy of analytical probability models such as those published in industry standard guidelines. A LOS probability distribution for UK street lamp posts is presented to quantify the feasibility of wireless fronthaul connectivity from macro cell hub sites to new street level small cells. In addition, generalised LOS results are presented at a range of end point heights permitting a new UMa model to be proposed. The new model addresses shortcomings of existing models whilst describing the likelihood for LOS conditions between macro sites and street canyon end points at heights of up to 10 m.

A modified Hilbert fractal geometry and serpentine radiator-based implant antenna is proposed for dual band medical operations in both the MICS band (402-405 MHz) and ISM band (2.4-2.48 GHz). The antenna has miniaturized dimensions of 5.5 x 7.6 x 0.8 mm(3) (width x height x thickness) and is simulated inside a four layer (air, skin, fat and muscle) model with dimensions of 150 mm x 75 mm x 55 mm. A Zirconia (epsilon(r)=29) superstrate and shorting pin were utilized to achieve biocompatibility and the desired resonance. Relatively stable and omni-directional radiation patterns were achieved for the dual band operation. An ISM band on-body antenna (5.8 x 5.5 x 0.8 mm(3)) was proposed to generate a wake-up signal while the wireless telemetry transmission was achieved using the MICS band onbody antenna (5.8 x 5.5 x 0.8 mm(3)). Implant and on body antennas demonstrated a reflection coefficient (S-11) better than -10 dB characteristics. To adhere to the SAR regulation limit of 1.6W/kg, the peak incident power should not exceed 0.25 mW and 0.2 mW for the ISM band and MISC band on-body antennas respectively. Propagation channel characteristics were simulated by observing the S-12 and S-13 characteristics and satisfactory results were achieved. The peak gain for the implant, MICS band and ISM band on-body antennas were -39.8 dBi, -35.6 dBi and -23 dBi, respectively due to the miniature dimensions. The miniaturized characteristics, dual-band operation, biocompatibility and stable characteristics in the presence of human tissue model make both the implant and on-body antennas suitable for biomedical monitoring systems.

A key challenge in deploying new wireless cellular technologies or architectures is accurate modelling of their impact on the wider network. In this contribution, we provide a new statistical framework and large scale analysis to characterise a real mobile network. Current industry guidelines relevant to modelling of mobile networks and their deployments are often over simplified and based on generalisation of the propagation environment and network topology. The following analysis details statistical deployment characteristics of mobile base station sites and their associated geographic environment using a highly detailed 3D topology model of large areas of the UK. High resolution LIDAR (Light Detecting and Ranging) data and cell mast properties are utilised to generate statistical descriptions of urban, suburban and rural cell site types as well as distributions for the clutter properties that can be found within each cell type's coverage area. Our findings illustrate the important distinction between traditional cell classifications using a range of attributes whilst also highlighting the unique 3D properties of urban cell types.

The drawbacks of legacy satellite positioning systems necessitate new procedures for high resolution location services. Moreover, location-aware devices, systems and networks are critical for 5G/future network setting that seeks to seamlessly connect global devices in an all-IP network. It is therefore believed that satellite positioning could be enhanced with impulse radio (IR) ultrawideband (UWB) localization approaches for accuracy-critical situations expected in 5G wireless. This paper presents results of research on enhanced satellite positioning methods for ultra-dense 5G setting. The methods combine information from satellites, fixed wireless networks, wireless LANs and cellular communication along with global cloud databases. This is conceptualized as an IR-UWB device-to-device (D2D) overlay network that seamlessly incorporates satellite data into the 5G terrestrial network environment. A link to at least one satellite on the global positioning constellation would suffice for accurate localization. Also presented is the IR UWB D2D-propagation-based combined localization and communication scheme (UD-CLOCS). The UD-CLOCS scheme transmits location and communication data in a single signal while performance evaluations have been impressive. It is believed that the solutions have potential for robust and cost-efficient satellite positioning as well as prospect to de-congest licensed spectrum in 5G wireless setting. The significance of the research outcomes is that satellite positioning signal and data could be seamlessly integrated into global 5G networks for enhanced positioning services as well as improved spectral efficiency.

From the clients' side, future generations of railway passenger services should deliver on-board data rate that exceed customer expectations. From the infrastructure perspective safety, security, maintenance and crime prevention must be enhanced in line with reduced journey times even on international services. At present, the gross information capacity of intra-train guided media at 100s Mbit/s is already inadequate ( Kbit/s per user) even as the roll-out of 5G technologies continues apace. This paper presents a new approach to providing higher data rates ( ≈ 100 Mbit/s per user) with rail-approved assemblies of media, such as twisted-pair copper cables and enhanced connectors. We present experimental throughput results on realworld railway rolling stock showing that standard Cat 5e and higher specification twisted-pair copper cable assemblies offer 40 Gbit/s data capacity between present-day train carriages.

In this paper we present the urgency for the optical transport networking evolution for 5G delivery and ultra-broadband services to users and communities of users, in the followings: (a) Cloud core, Metro-cloud core and edge cloud networking structure with optical SDN and SDN/NFV. (b) Photonic enabled technologies including principal devices and photonic processors. (c) Security aspects and transmission technology for secret keys in co-transmission of massive data transport.

The allocation of 60GHz spectrum for WLAN has made the quests for gigabit data rates delivery to the end users possible in the wireless communication domain. The peculiar propagation characteristics in the millimetre wave can be exploited for improved system capacity. In optimizing beamforming techniques, a weight vector that minimizes a cost function is determined. The most commonly used optimally beamforming techniques or performance measures (cost function) are Minimum Mean Square Error (MMSE), Maximum Signal-to-Noise ratio (MSNR), and Minimum (noise) Variance (MV). A matlab based MVDR (Minimum Variance Distortion Response) and Phase-Shift Beamforming algorithms are proposed in this paper as means for cognitive spatial access in the millimetre wave band to enhance the signal of interest (SOI), with the suppression of interferences. Simulation results reveal that MVDR outperforms the PhaseShifts in interference limited spatial multiple access (SMA) systems.

Research on the electrical characteristics of hydroelectric power systems has, to our knowledge not received much attention. However, renewed interest in hydropower microgeneration has created a need to understand the underlying properties. This paper presents a pioneering empirical investigation into the electrical characteristics of micro-hydro power generators (MHPGs). We demonstrate ohmic characteristic behavior in MHPGs with constant source impedance, even with varying water flow. A novel heuristic model for hydroelectric power generator is then described and validated through Simulink simulation.