Analogue-to-digital converters (ADCs) are the essential links between physical world in which all signals are 'analogue' (e.g., electric current generated by a microphone or a picture captured by a mobile phone camera) and the digital world of '0s' and '1s', where we store, transmit and process signals and information. ADCs enable (digital) computers to process signals from the (analogue) physical world. This capability has revolutionised our entire society, making computers (desk-tops, lap-tops, or smartphones) ubiquitous. In recent years, we have witnessed a dramatic increase of the amount of information that is generated, stored, transmitted, and processed, driven by increased demand of our society on data and information and newly emerging applications such as virtual and augmented reality. All this information needs to be processed by ADCs, which can address the abovementioned need only when performing with better accuracy, affordable power consumption, in real-time (with low latency), and for increasingly broader bandwidth (faster) signals. This is extremely challenging with currently-existing technologies and is being vigorously pursued by both academia and industry. Most of these approaches are based on strategies like the use of application-specific integrated circuits (ASICs), photonic time stretch, or time interleaving. Unfortunately, all of these approaches seem to have formidable challenges. A clearly realisable route to next-generation ADCs that could support information growth in the next decade and beyond is currently lacking. ORBITS aims to provide a radically novel and future-growth-proof solution to ADCs using optical assisted means. Specifically, it will exploit unique features of recently-emerged optical and photonics technologies, including optical frequency combs, coherent optical processing, and precise optical phase control. Optics offers three orders of magnitude larger bandwidth than microwave electronics used for ADCs today and has the advantages of ultrafast (femtosecond level) responses. The optical frequency comb technologies, in conjunction with coherent optical processing and phase control, enables dividing signal with high accuracy in the optical domain, which overcomes the fundamental limits such as timing jitter (time uncertainty) in conventional approaches, opening up a scalable and integratable technology for large bandwidth high resolution ADCs. For practical (low-cost when volume-manufactured, compact, and low-power-consuming) implementation, ORBITS will investigate optical and electronic integration, which permit to harness merits across different photonics integration platforms, through collaborations and open foundries. Besides next-generation ADCs, ORBITS will study applications in future-proof high capacity optical and wireless communications. It assembles complementary expertise from top research groups in Universities and companies, aiming for a wide academic impact and a straightforward knowledge transfer to industry.

Users want mobile devices that appear fast and responsive, but at the same time have long lasting batteries and do not overheat. Achieving both of these at once is difficult. The workloads employed to evaluate mobile optimisations are rarely representative of real mobile applications and are oblivious to user perception, focussing only on performance. As a result hardware and software designers' decisions do not respect the user's Quality of Experience (QoE). The device either runs faster than necessary for optimal QoE, wasting energy, or the device runs too slowly, spoiling QoE. SUMMER will develop the first framework to record, replay, and analyse mobile workloads that represent and measure real user experience. Our work will expose for the first time the real Pareto trade-off between the user's QoE and energy consumption. The results of this project will permit others, from computer architects up to library developers, to make their design decisions with QoE as their optimisation target. To show the power of this new approach, we will design the first energy efficient operating system scheduler for heterogeneous mobile processors which takes QoE into account. With heterogeneous mobile processors just now entering the market, a scheduler able to use them optimally is urgently needed. We expect our scheduler to be at least 50% more energy efficient on average than the standard Linux scheduler on an ARM BIG.LITTLE system.

The advent of the first mobile phones in the 1980s marked the beginning of mobile communications for commercial purposes. Now, thirty years later, wireless connectivity has become a fundamental part of our everyday lives and is increasingly being regarded as an essential commodity like electricity, gas and water. This unparalleled success means that we are today facing the imminent shortage of radio frequency (RF) spectrum: It is predicted that the amount of data sent through wireless networks will increase by a factor of 10 during the next five years. Moreover, data from Qualcomm demonstrates that the spectrum efficiency (number of bits transmitted per Hertz bandwidth) is saturating. Therefore, the US Federal Communications Commission has warned that a "spectrum crisis" is looming. The proposed work in this EPSRC Fellowship is aimed at providing radical new solutions to this fundamental and far reaching challenge. A key pillar of the proposed work is the extension of the RF spectrum to include the infrared as well as the visible light spectra. The recent advancements in light emitting diode (LED) device technology now seems to let the vision of using light for high speed wireless communications become a reality. Using light has many key advantages as compared with RF. The available spectrum is vast, the visible light spectrum is 10,000 times larger than the RF spectrum; it is free as it is not subject to government regulations; it is more secure than the radio frequency spectrum the signals of which can be intercepted outside a premise; it can achieve three orders of magnitude higher data density per unit area. Compared to the infrared spectrum, the visible light spectrum has additional advantages. First, it is not power-limited due to eye-safety concerns. Second, it can serve two purposes at the same time: illumination and high speed data transmission, resulting in a better use of energy. However, while several hundred megabit per second (Mbps) have been demonstrated for a single link using an off-the-shelf white LED, 1 gigabit per second (Gbps) and room coverage is still an open issue. In addition, there is little research for multi-user networked OWC systems. Also, the effects of dimming on the achievable data rates are not well understood. In addition, there are environments and scenarios where the use of light is difficult or not possible such as when there is heavy blockage between transmitters and receivers, or when terminals move with high speeds. In those situations, it will still be more appropriate to use the RF spectrum. To sum up, there are potential large overall performance improvements when wireless systems can select their transmission medium autonomously and in a dynamic as well as self-organising fashion. A second essential pillar of the proposed research is to overcome the RF spectrum efficiency saturation of current cellular systems while at the same time reducing the energy consumption. A key to solving this issue is to successfully tackle interference in wireless networks which occurs when multiple communication links in close vicinity use (or reuse) the same bandwidth or frequency. On the one hand frequency reuse is beneficial since the more often transmission resources are used per unit area, the higher the spectrum efficiency. On the other hand, intensive frequency reuse results in the aforementioned interference issues. Radically new approaches will be followed that include interference already in the design of a new wireless air-interface. In the past, wireless air-interfaces were optimised for single transmission links, and performance degradations due to interference in a system deployment were mended subsequently, but existing solutions are either impractical or sub-optimum. We will investigate a new air-interface that is based on the recent successful demonstrations of and world-wide research on the concept of spatial modulation which was originally proposed by the applicant.

We are on the verge of a global revolution in lighting, as efficient and robust light emitting diode (LED) based 'solid state lighting' (SSL) progressively replaces traditional incandescent and even fluorescent lamps and finds its way into new areas including signage, illumination, signalling, consumer electronics, building infrastructure, displays, clothing, avionics, automotive, sub-marine applications, medical prosthetics and so on. This technology has tended to be viewed, so far, primarily as a way to improve energy- and spectral-efficiency, but what has been relatively little studied or appreciated is its profound implications for the future of communications. We envisage the tremendous prospect of an entirely new form of high bandwidth communications infrastructure to complement, enhance and in some cases supercede existing systems. This LED-based technology will utilise the visible spectrum, largely unused for communications at present and more than 10,000 broader than the entire microwave spectrum. This promises to help address the 'looming spectral crisis' in RF wireless communications and to permit deployment in situations where RF is either not applicable (e.g. in underwater applications) or undesirable (e.g. aircraft, ships, hospital surgeries), but the implications are more fundamental even than that. The key point, in our view, is that lighting, display, communications and sensing functions can be combined, leading to new concepts of 'data through illumination' and 'data through displays'. Imagine, for example, a 'smart room', where 'universal illuminators' provide high-bandwidth communications, sensors monitoring the environment and people within it, provide positioning information and display functions, and monitor the quality of the light. Imagine novel forms of personal communications system that combine display functions and video with multiple, high-bandwidth communications channels. These could be through mobile personal communicators (developments of mobile phones or personal digital assistants) or even wearable and mechanically flexible displays. Our ambitious programme seeks to explore this transformative view of communications in an imaginative and foresighted way. The vision is built on the unique capabilities of gallium nitride (GaN) optoelectronics to combine optical communications with lighting functions, and especially on the capability of the technology to implement new forms of spatial multiplexing, where individual elements in high-density arrays of LEDs provide independent communications channels, but can combine as displays. We envisage ultra-high data density - potentially Tb/s/mm2 - arrays of LEDs in compact and versatile forms, and will develop novel transceiver technology on this basis on both mechancially rigid and mechanically flexible substrates. We will explore the implications of this approach for multi-channel waveguide and free-space optical communications, establishing guidelines and fundamental assessments of performance which will be of long-term significance to this new form of communications.

Depletion of natural resources combined with the extending footprint of mankind has led to a shift in importance of research and development topics. In the 1970s and 1980s process yield was primarily targeted, but emphasis is now focussed on resource efficiency as a primary objective. Routes for resource efficiency have to be identified and implemented to provide a more environmental and resource-oriented technology in near future. MIGRATE is planned as an ETN, gathering top-level research and development capabilities from academia and industry as well as direct application possibilities with the focus set on thermal aspects of gas flows in microstructured systems. Within MIGRATE, a number of ESR projects will cover different aspects of enhanced heat transfer and thermal effects in gases, spanning from modelling of heat transfer processes and devices, development and characterization of sensors and measurement systems for heat transfer in gas flows as well as thermally driven micro gas separators to micro-scale devices for enhanced and efficient heat recovery in automotive, aeronautics and energy generation. This unique combination of university research, SME and world leading industrial stakeholders will contribute in a significant way to the increase of knowledge about micro scale gas flow heat transfer problems as well as to industrial applications of highly efficient miniaturized devices. A characteristic of MIGRATE is the high degree of applicability and the intense training. About 30% of the beneficiaries are from private sector. Thus, ESR projects will be developed in both directions, fundamental academic knowledge as well as direct application in industrial environment. The training of the ESRs is set in the same way to provide a broad variety of skills, reaching from classical academic research to IPR management and all-day-business in a company, being summarized under the aspect of resource efficiency and environmental-friendly technological approaches.