Towards terabit wide-coverage indoor optical wireless communications
Mr Ariel Gomez Diaz
Wireless transmission capacity has always lagged that of optical fibres, usually by many orders of magnitude. High-frequency RF wireless offers rates closer to that of fibres, but at the carrier frequencies used and allowed power levels only narrow line of sight channels are available. This capability comes at the cost of complex electronics and components. Our approach is to dispense with the RF channel, and to build a fibre-(optical wireless)-fibre link. Holographic beamsteering is used to direct light exiting a fibre through free space to a terminal where a similar holographic beamsteerer is used to couple the light back into the fibre. This leads to a transparent optical end-to-end architecture that operates bi-directionally. We have demonstrated an eye-safe point-to-point, bidirectional, 112 Gigabit/s wide field of view link that uses coherent optical transmission, with a coverage area of 35 m2 in an indoor room-like environment. This system has the potential to provide Terabit/s aggregate data rates to nomadic users. Performance compares extremely favourably with high-frequency radio frequency line-of-sight approaches, at much reduced complexity, intrinsic transparency and bi-directional operation. Such an approach has the potential to create an all optical network, spanning both wireless and fibre domains, with near term application in broadcast and data centres, and longer term applications in ultra-high speed indoor systems.
Towards ultimate convervence of all networks
Professor Dimitra Simeonidou, University of Bristol, UK
Global demand for broadband communications continues to increase substantially every year. A major factor contributing to this demand is the growing number of fixed and mobile broadband users, data-hungry applications like video as well as an ever-increasing number of network-connected everyday objects and machines. These trends pose entirely new challenges related to data volume, granularity, end-to-end connectivity and reach as well as increasing heterogeneity in network technologies (i.e. wireless and wired), networked-connected devices (i.e. sensors, mobile phones, computers, TVs, Data Centres) and services (i.e. Tbps data transfer for e-science, ultra-low latency financial transaction, real-time media streaming, kbps for sensor-based monitoring). Addressing these challenges necessitates radically new network models supporting convergence of traditionally separate network technology domains and offering high flexibility and adaptability in data granularity and throughput. This talk will discuss novel approaches to achieve ultimate network convergence enabled by radically new technology agnostic architectures targeting a wide range of applications and end users. The aim is to facilitate optimal interconnection of any network technology domains, networked devices and data sets with high flexibility, resource and energy efficiency, and to satisfy the full range of Quality of Service (QoS) and Quality of Experience (QoE) requirements.
Orders of magnitude higher throughput in cellular communications by optical attocells
Dr Dushyantha Basnayaka, University of Edinburgh, UK
Global mobile voice and data traffic reached 2.5 exabytes (2.5 billions GB) per month at the end of 2014, up from 1.5 exabytes per month at the end of 2013, and monthly global mobile traffic will surpass 24.3 exabytes by 2019. Clearly this exponential growth cannot be handled by radio frequency (RF) cellular networks alone. Major telecommunication operators worldwide already offload some if not majority of mobile traffic onto Wi-Fi networks. As a consequence, about 80 percent of all data traffic on smartphones currently travels through Wi-Fi networks. However, the radio spectrum is limited. In contrast, the visible light spectrum is 10,000 times larger than the entire 30 GHz of RF spectrum which currently hosts all commercial RF systems. This has led to the introduction of Li-Fi which defines high-speed, bidirectional, networked and mobile wireless communications using light. Li-Fi opens up the opportunity to introduce a new small cell layer to the currently deployed heterogeneous wireless networks. A network of Li-Fi access points forms the optical attocellular layer which does not create any interference to existing RF networks. The Li-Fi attocell layer exploits the existing lighting infrastructure, and off-the-shelf LED light bulbs. The recent research efforts dedicated to Li-Fi have resulted in a number of advancements. They include the new generation of faster LEDs and modulation schemes which enable multi gigabyte indoor communication links, and multiuser Li-Fi systems for both uplink and downlink, and self-sufficient optical energy harvesting VLC access points. The current theoretical and experimental research at University of Edinburgh considers networking challenges of Li-Fi systems such as optimum attocell deployment scenarios, resource allocation schemes, and load balancing schemes to enhance the average and outage user rate performance. Moreover, our research shows that hybrid Wi-Fi and Li-Fi systems can significantly improve capacity, coverage and user experience which is an important finding in the context of 5G requirements such as to support 100 times more devices to enable the Internet of Things as well as to carry 10,000 times increased wireless traffic. This talks summarises the key research findings on the introduction of a new optical attocell layer in heterogeneous wireless networks aimed at future 5G networks.
High fidelity optical carrier dissemination using coherent communication techniques: HIPERFREQ Project
Dr Ehsan Sooudi, Tyndall National Institute and Department of Physics, University College Cork, Ireland
Dissemination of optical clocks enables wider usage of such precise frequencies in fundamental physics tests, comparison of frequency references and definition of a second. Current dissemination techniques involve a bi-directional link and amplifier to stabilize the delivered optical carrier which is all-optical and usually requires a dedicated (dark) fibre link. This scheme is not generally deployable within the fibre-based telecommunication networks in which optical/electrical/optical conversions are occurring and the transmission is uni-directional. Emerging applications such as novel GPS systems and time synchronization and frequency transfer through optical networks require dissemination schemes deployable in optical networks. In this presentation, we discuss the HIPERFREQ project with European Space Agency which investigates a uni-directional dissemination approach based on coherent communication techniques, compatible with fibre optic networks. For the first time, a 10 Gb/s BPSK signal from an ultra-narrow linewidth laser was transmitted through a field-installed optical fibre with round-trip length of 124 km from Cork to Clonakilty using self-homodyne detection and optical injection-locking to recover and re-generate the optical carrier. The beating linewidth of the original carrier and the transmitted one was measured to be ~ 2.8 kHz with long-term fractional stability (true Allan deviation) of 3.3 x10-14 for 1 s averaging time.
Optimisation technique for optical OFDM systems
Miss Funmilayo Ogunkoya, Glasgow Caledonian University, UK
The convergence of technology, embedded computing devices, telecommunication and networking of systems, devices and services has led to the development of integrated applications and increase in data traffic over transmission media. Optical wireless communication (OWC) systems have been demonstrated as a transmission technique that can meet the ever-increasing data rate demand of these applications. However, one of the modulation techniques in OWC – orthogonal frequency division multiplexing (OFDM) – capable of supporting high data rate suffer from high peak-to-average power ratio (PAPR) problem. Transmission of optical OFDM signal with high peaks results into bit-error rate (BER) degradation. In this work, we present performance evaluation of the pilot-assisted OFDM PAPR reduction technique proposed for optical communication systems using empirical and theoretical approach. The PAPR reduction is achieved by rotating the phase of OFDM data symbols with P-iterations of randomly generated pilot symbol. Conventional OFDM system utilises pilot signal for channel estimation. In our work, we use the pilot signal to serve a dual purpose of PAPR reduction at the transmitter and channel estimation at the receiver to enhance OFDM. Our results show that the PAPR values of the pilot-assisted OFDM are lower than that of basic OFDM where no PAPR reduction technique is applied and there is no BER penalty in implementing the pilot-assisted technique.
Engineering emergence for large-scale cyber physical systems through software
Dr Mariam Kiran, University of Bradford, UK
The emergence of technologies, with ‘Internet of things concept’ of connected devices has given rise to a world controlled by software. This software needs to be intelligent to control network formations, perform load balancing, for dynamic and manageable architecture formation to allow a cost effective emergent network. Agile methodologies and on demand ‘everything as a service’ services through cloud computing, need to come together to understand the lower level software interactions to make intelligent formations emerge at higher levels.
My research involves investigating issues on how lower lever interactions, using software, can aid in formation of intelligent emergent architectures for the Internet of things or cyber physical systems. I am using principles of complex systems such as insect colonies to allow individual units to interact in manners to allow large scale society behaviours to emerge. These concepts are adopted in software based agents which interact with other similar agents to evolve behaviour of large scale networks. This research also involves investigating issues of risk, security, network resilience and data transfer to build reliable decentralised cloud networks which act as complex systems for achieving efficient data management for Smart City applications, mimicking how natural systems build complex reliable structures.
Seamless and adaptive interfaces for wired and multi-technology wireless for future converged networks
Dr Paul Anthony Haigh, University of Bristol, UK
In this talk, an overview of the recently funded EPSRC TOUCAN project; which aims to provide major innovation in network convergence. As opposed to modern day, where the majority of access networks are based on Wi-Fi, in the future it is foreseen that access networks will be based on multi-technology components such as LTE, Li-Fi, Bluetooth and Wi-Fi, amongst others. Each of these technologies has its own standards, protocols and throughput requirements. This presents a significant challenge to network designers at the access/intermediate network edge who must provide a transparent interface as well as efficient aggregation of the data flows, making best use of resources. Here, this interface will be discussed including current progress and future directions.