Future Wi-Fi: enhanced indoor modelling and waveform design & analysis

Wi-Fi technologies are integral to our internet-connected lives. In excess of 70% of the world's wireless data passes over one of the global Wi-Fi standards. For more than 20 years the University of Bristol's Communication Systems and Networks (CSN) Group has contributed towards the development of these technologies, and to products that conform to them.

WiFi presents opportunities for mobile working and cost savings which are attractive to many organisations. How-ever, security requirements pose a number of challenges with regard to unauthorised interception, exploitation or service denial and need to be considered in any installation. Encryption and authentication provide some of the answer, but there is also a need to determine from an Information Assurance (IA) perspective how far wireless sig-nals may 'leak' outside the intended coverage area. To this end there is an interest in understanding the indoor propagation environment with greater fidelity, to determine conditions which may cause an overall propagation loss lower than would be expected from spherical spreading in free space over the same distance.

The first year will be spent developing an indoor ray-tracing model (this will extend the capabilities of the tool used in the Mobile Communications Lab). The model will consider different property types, wall thicknesses and material types, and will support arbitrary building structures (including large multi-user dwellings). The primary focus will be on the established 2.4 and 5.8 GHz bands however to future proof the model, mmWave frequencies (unlicensed 60GHz band) will be considered also to ensure support for future in-building radio standards such as IEEE 802.11ad.

The ray-tracing model will be combined with full 3D antenna measurements, with sophisticated system-level simula-tors of the latest Wi-Fi standards (code already exists). In order to improve the accuracy of the model measurements will be made for a range of scenarios, for example propagation along corridors, false ceilings, cable ducts and stair-wells, with the goal of identifying cases which give a larger range than would normally be expected. Similarly MmWave measurements will be taken in several properties to tune, calibrate and verify the ray-tracing operation (i.e. the underlying diffraction and diffuse scatter interactions with walls, floors and ceilings. The project will make use of the CSN Group's multi-million pound equipment and facilities, such as our anechoic chamber and our wideband channel sounder and channel emulators.