Modelling, Analysis, and Design of Ultra-Dense Cellular Networks

Wireless communications technology enables us to seamlessly access many multimedia services, e.g., stored multimedia (e.g., video on-demand), live streaming (e.g., Internet live sport networks, Internet radio stations), and realtime interactive streaming (e.g., online games, video conference, e-education), etc. As such, wireless communications technology has rapidly gained a crucial role and become an important aspect of life.
There is a strong, credible body of evidence, suggesting that mobile network operators are facing many formidable tasks but exciting areas of endeavour. Of most concern is the increase in ever-growing wireless/mobile devices and the huge demand in data rates associated with this. It is predicted that the number of mobile-connected devices will exceed 11.5 billion by 2019 (nearly 1.5 mobile devices per capita), which poses a huge traffic demand for ubiquitous communications. On the one hand, it is anticipated that we will witness an up to 10000- fold growth in wireless data traffic by the year 2030, and that of the UK alone is projected to increase between 23-fold and 297-fold over the period 2012-2030.
The future 5G cellular network is expected to achieve as much as 1000 times data rate relative to its current 4G counterpart. On the one hand, as many as 50 billion devices will be connected to the Internet by 2020 request seamless connectivity and mobility. Data rates are projected to increase by a factor of ten every five years, and with the emerging Internet of Things (IoT) predicted to wirelessly connect trillions of devices across the globe, without novel approaches, future mobile networks (5G) will grind to a halt unless more capacity is created.
One of the most attractive solutions is the implementation of ultra-dense networks constituted by the combination of macro-cells and small-cells and exploited the emerging technologies of millimetre wave (mm-wave) frequency bands, large-scale antennas arrays. But while these enabling technologies constitute one of the most attractive approaches, i.e., ultra-dense cellular networks, to improving the capacity and coverage of wireless systems, the "ultra-dense" aspect poses fundamental challenges, which urgently require solutions.
Most importantly, the tool of system-level performance evaluation and optimization is very essential for telecommunication service providers. However, it is usually conducted by relying on numerical simulations, which are often time-consuming and even extremely difficult in the context of 5G ultra-dense networks. At present, no sound but essential mathematical methodologies towards the design of practical communication protocols and transmission techniques for ultra-dense heterogeneous cellular networks are available.
Motivated by this lack of tractable solution, this research project proposes a mathematical model to take into account the practical aspects of 5G ultra-dense networks, i.e., highly dense distribution, dynamic random topologies, and heterogeneous interference. The unique feature of the project is to augment the recent advances in mathematics, random process, and signal processing theory involved by both base stations and mobile devices in ultra-dense cellular networks for recovering the transmitted voice, data, video, etc. This allows us to integrate interference management between large and small cells along with a large number of transmit/receive antennas and higher transmission bandwidth in mm-wave frequency bands. These include the development of new theoretical framework that is informed by the limitations of a practical system not currently considered in the context of "extremely dense networks" of current cellular systems.

The beneficiaries include users of wireless connections who will expect high data rate; business who will depend on high data rate connections to enhance customers' experience; industry who will need energy-efficient solutions; government organizations who are seeking solutions to more efficient services through ubiquitous access "anywhere, anyhow" and at any time (e.g., National Health Services - NHS).

Through our social media group (LinkedIn group), we will contribute to raising awareness among general public of the outcomes of our project, 5G technologies and their anticipate capabilities, with a view to generating demand for 5G and its associated services.

Our research will support the quest for ubiquitous access to a wider spectrum of applications and services offered at a lower cost, with increased resilience and continuity, with higher efficiency of resources usage.
5G is expected to meet requirements from massive broadband, mission critical, communications, as well as covering the needs of massive machine type communications and possible other usage of wireless communication, from low to high mobility, using microwave frequencies below 6GHz or at mm-waves, with various deployment schemes. From the perspective of users, the project will be of interest to the technology industry in the UK given the expected outcomes (models and designs) that help to depict the future 5G wireless networks in the form of ultra-dense cellular networks. New revenue generating streams and new value chain models can be seen in the UK's connectivity segment, which currently accounts for 35% of the UK's ICT market revenues. Further down the value chain, end-users can benefit from a wide range of applications that are enabled through the core advantages, i.e., high capacity and high efficiency of ultra-dense cellular networks. Examples include
a) Wearable devices that can monitor and transmit data in near-real-time to a health service instead of being manually monitored in a costly hospital. This helps to reduce the healthcare costs to the NHS and enhance patients' quality of life;
b) Transportation: real-time information sharing between vehicles, which may reduce congestion (thus less CO2 emission); video streaming via full 5G network connectivity on high-speed trains, which make travelling more enjoyable
Finally, system-level performance evaluation and optimization of cellular networks are usually conducted by relying on numerical simulations, which are often time-consuming and cannot reveal additional insights into the effect of various parameters on the system performance without analyzing a sufficiently large set of data. As such, the availability of the mathematical modelling and methodology in this project will be very essential for telecommunications industry (e.g., service providers) to verify new protocols and algorithms (without expensive trials) before being ready for the practical implementation.

The PI has estimated and well planned all the cost related to achieve the research impact of this proposal, e.g, organising special sessions, special issues, workshops, and visiting industry and academia. Furthermore, the opportunity to engage directly with industry partner Keysight Technologies, academic collaborators, and other industrial collaborators will expose the project's researcher to world class wireless communications expertise, which will enable him to disseminate the research outcome and gain valuable feedback.