SC445 - Optical Wireless for Mobile Communications
Monday, 04 March
13:30 - 17:30
Short Course Level: Advanced Beginner
Harald Haas; LiFi Research and Development Centre, The University of Edinburgh, UK
Short Course Description:
The use of the optical spectrum for wireless communications has gained significant academic and commercial interest in recent years. The applications range from low rate simplex transmission links using existing embedded CMOS cameras in smartphones, referred to as optical camera communications (OCC), mobile light fidelity (LiFi) networking in homes, offices and urban environments to free-space gigabit interconnects in data centers and point-to-point long-range wireless backhaul links outdoors. In this tutorial we will focus on the use of optical wireless communications (OWC) for mobile use cases. We treat this as a natural extension of fibre networks (without the fibre) to include mobile access. We will set the scene by looking at existing conventional radio frequency (RF)-based wireless access technology and state clearly its limitations with respect to the requirements of the future wave of artificial intelligence (AI) driven autonomous systems and machine-type communications in general. Then we will go on to provide a general background to the subject of optical wireless communications. In this context, we will provide a summary of the history of OWC, followed by the introduction of a taxonomy for OWC technologies. In this context, we will discuss the relationship between visible light communications (VLC) and light fidelity (LiFi), introducing the major advantages of VLC and LiFi such as security and data density, and discuss existing research challenges. Recent key advancements in physical layer techniques that led to free-space transmission speeds greater than 10 Gbps will be introduced. Moving on, we will provide channel modelling techniques for mobile multiuser scenarios, and will introduce key building blocks to achieve optical attocellular networks achieving orders of magnitude improvements of area spectral efficiency compared to state-of-the-art technologies. The challenges that arise from moving from a static point-to-point visible light link to a LiFi network that is capable of serving hundreds of mobile and fixed nodes will be discussed. An overview of recent standardization activities will be provided. Lastly, we will moot commercialisation challenges of this disruptive technology.
Short Course Benefits:
This course will enable you to:
Understand the limits to conventional WiFi technology and how light can provide significantly higher bandwidth
Describe key optical wireless technologies such as infrared, VLC and LiFi
Explain practical limitations such as link margins using intensity modulation / direct detection (IM/DD), receiver sensitivity, impact of sun light and impact of random blockages and non-line of sight conditions
Compare different digital modulation techniques used in IM/DD wireless systems in terms of spectrum efficiency and energy efficiency as well as various environmental conditions
Introduce optical attocells and various concepts including the latest infrared beamstearing solutions
Discuss methods to achieve an optical uplink/reverse link assuming random orientation and random blockages
Discuss pros and cons of angular diversity and multiple input multiple output techniques in optical attocell networks
Summarise methods to achieve multiuser access and to support mobility in optical attocell networks
List practical co-channel interference mitigation techniques in LiFi attocell networks
Explain how the downlink capacity of optical attocell networks could be obtained taking into account specific properties of IM/DD - for example, that fading does not exist unlike in RF
Discuss the potential commercial opportunities offered by LiFi to the wireless communications and lighting industries and the wider eco-system
Short Course Audience:
This advanced-beginner course is intended for a diverse audience including lightwave system researchers and engineers as well as photonic device researchers and engineers and optical sub-system designers. The course should also be of interst to reseachers and practitioners in fibre optic communication who see an all-optical future where light also plays a major role in wireless access networks. Some basic knowledge of intensity modulation and direct detection techniques will be useful, but is not a prerequisite. The same applies to basic knowldege of wireless access networks.
Harald Haas holds the Chair of Mobile Communications at the University of Edinburgh, and is the Director of the Li-Fi R&D Centre. He is founder of pureLiFi Ltd. He first coined Li-Fi and was an invited speaker at TED Global 2011 and 2015, and his talks have been watched online more than 4 million times. In 2014, he was selected by EPSRC as one of ten RISE (Recognising Inspirational Scientists and Engineers) Leaders in the UK. In 2017, he was elected Fellow of the Royal Society of Edinburgh.