The next generation of mobile communication, 5G, is now this side of the horizon but its form remains indistinct and shrouded in mist.
Despite the enormous research efforts into 5G mobile technologies, there remains uncertainty on what services will drive the deployment of 5G networks, and which of these services will be delivered by mm-waves.
ATDI technical director Nick Kirkman comments: “A consensus is emerging that important characteristics will include perceived ubiquity of service, very low-latency (for virtual reality, real-time control, etc.) and an order of magnitude increase in supported bit-rates. While ‘traditional’ cellular frequencies below 6 GHz will continue to be critical to such networks, it is also anticipated that millimetre-wave frequencies will be exploited to allow high data rates over short distances.”
A number of frequency bands between 25 GHz and 86 GHz are currently being studied under the auspices of the International Telecommunication Union. Industry collaboration projects such as mmMagic (Horizon 2020) are looking to characterise radiowave propagation at frequencies above 6 GHz. However, the development of site-specific models for planning at these frequencies has received little attention.
Paul Grant, ATDI’s operations director, notes: “At these high frequencies, coverage planning techniques will be radically different from those used today. Diffraction losses are so high that there is an almost binary switch between ‘served’ and ‘unserved’ areas as shadowing by environmental clutter interrupts the line-of-sight between base station and user.
“It is likely that small cells will make extensive use of beamforming and MIMO techniques, required because of the high path losses and made feasible by the small antenna sizes. This implies that a useful prediction model will need to take account of scattered and reflected energy; this provides a challenge as it is a computationally more intensive task than the direct-path predictions generally used in operational planning models. Such predictions are also likely to require rather detailed data concerning building facades. The proposed study will be a valuable opportunity to understand the improvement such data can bring to coverage and capacity modelling.”
Nick adds: “The current trend in the mobile industry is towards self-optimising networks but this does not imply that there is no role for planning. With the cost of access to sites for base stations rising rapidly, it is an urgent matter to ensure that the best use is made of physical resources. The output of this project will help to minimise 5G network deployment cost and increase efficiency.”
The planning techniques being developed by ATDI are more sophisticated than anything that has been publicly reported for outdoor deployment of 5G mm-wave networks.
“We are aiming to provide insight into the viability of use cases for 5G at mm-waves,” Paul says. “One typical area would be the deployment density needed for base stations. This will be valuable both for government in developing its policy for 5G and industry in developing business cases for 5G.”