PhD Studentship - Physical Layer Security for Mobile Optical Wireless Communications Systems

Faculty of Engineering and Physical Sciences EPSRC Project Proposals 2025/26

Funding: School of Electronic & Electrical Engineering Studentship consisting of the award of fees, together with a tax-free maintenance grant of £19,237 per year for 3.5 years (Competition). 

Lead Supervisor’s full name & email address

Dr Farah Al-Sallami: F.Al-Sallami@leeds.ac.uk

Project summary

Optical wireless communication (OWC) is a highly directive communication system. This directivity hinders its practical implementation in mobile applications. Short-range OWC systems, which integrate lighting and communication functionalities and support multiple users using LED sources, are commonly referred to as visible light communication (VLC). In comparison, long-range device-to-device OWC systems that utilize laser sources are known as free space optical (FSO) communication. While the directive nature of OWC has been believed to offer security advantages, it does not guarantee security in multiuser VLC systems as the authenticity of users is not guaranteed.

Although the narrow laser beam in an FSO system expands 1000 times less than RF-based long-range communications beam (such as satellite systems) and it can be controlled using optics, very narrow beam divergence is undesirable because it causes misalignment errors due to sway, vibration, and jitter. With the advances in photodetectors, a 10 cm receiver aperture can interrupt the broad optical beam and align with the transmitter, which exposes the FSO link to security threats. Securing OWC links by cryptography, which relies on the computational complexity of the code used to encrypt the transmission, has yet to be noticed. This is likely due to the prevailing consensus within the research community that it is not a significant threat because of the narrow optical beam.

This assumption should not be taken for granted for long-range systems. Physical layer security (PLS) was investigated for OWC. This technology employs the information theory concept depending on the supremum of the difference between the lower bound on the legitimate channel capacity and the upper bound on the wiretapping channel capacity across all input laws. Assuming perfect knowledge of the channel states, the transmitter beamforms the transmission into the null space of the eavesdropper. However, research activities have investigated PLS for OWC, but all previous PLS schemes considered static (fixed) OWC systems. In mobile systems, the dynamic environment nature is continuously changing channel conditions. Hence, novel techniques are required to sense the channel and beamform the transmission into the null space of the eavesdropper.

Please state your entry requirements plus any necessary or desired background

A first class or an upper second class British Bachelors Honours degree (or equivalent) in an appropriate discipline.

Subject Area

Electronic and electrical, telecommunications, optical physics

For full details and to apply, please click on the ‘Apply’ button above

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