Green Heterogeneous Networks

The tremendous development of mobile networks has enabled ubiquitous communication that has transformed the way people connect with each other. With fast and reliable information exchange, mobile communication is becoming (if not yet) a daily necessity. However, existing mobile networks are not "green". Although much efforts has been invested in exploring energy efficient techniques for mobile phones, this is not so for base stations and mobile networks. As of 2008, mobile networks consume around 0.5% of global electricity, which is a significant amount for one particular industry. To make matters worse, this consumption is expected to rise by 200% within the next few years. With increased electricity price, this high energy consumption will increase the operation expenditure for mobile operators, which results in higher cost-per-Mbyte. This will create difficulties for mobile operators, and will also impact on pricing for consumers. On the other hand, the increased energy consumption will lead to higher CO2 emission. Given the threats of global climate change, it is highly desirable for future mobile networks to be more energy efficient and thus more environmental friendly.

Equally important, the need for higher data rate mobile communication is ever increasing. First of all, even with the extensive development of third generation (3G) mobile network, a recent study by the BBC shows that 25% of the time users will only able to access the much slower second generation (2G) network. This slow connection is a bottleneck for true ubiquitous communication. Therefore, to bridge the digital divide, there is a strong desire by the government, operator, and user to have high data rate connections everywhere. Secondly, the remarkable growth of high quality multimedia and social networks has pushed mobile data rates to the limit, and thus faster networks for the future are required. Although the 3GPP LTE (Long Term Evolution) and 802.16j (WiMax) will ease some of these pressures, advanced network topology and techniques are needed. Research work has already been started on IMT Advanced, which is the next generation mobile network. It aims to achieve a peak data rate of 1Gbps.

The most promising approach for IMT Advanced is the Heterogeneous Network (HetNet). It is an advanced network topology that cooperates between multiple tiers of base stations, i.e., macro, micro, pico, femto and relay base stations. By intelligent interference management, HetNet exploits frequency reuse to its maximum, and provides high data rate coverage everywhere. However, existing research on HetNet has focused mostly on the high data rate aspects, but rarely on the energy efficiency aspects. In this project, both goals on high energy and spectral efficiency will be targeted jointly. In particular, we will develop innovative techniques to provide radical improvement, instead of incremental enhancement. Adaptive network topology that can optimise these factors will be devised. Smart interference management and exploitation techniques will be developed to exploit the potential of HetNet. Network MIMO, cognitive radio, and 3 dimensional beamforming techniques will also be developed to achieve a green HetNet that is suitable for the future. The goal is to develop new technologies that can reduce energy consumption while providing the required data rate increase.

The world has been transformed by communication technologies. High speed and reliable communication networks enable various ways for people to connect, and with the popularity of mobile networks, ubiquitous communication is now common in many countries. Apart from conventional communication means such as voice call or email, communication networks have allowed the development of social media, which is the key platform for recent revolutions in the Arab world. The impact of ubiquitous communication networks on society has just started to show its immense potential. Moreover, ubiquitous communication also underpins the digital economy, which will drive the economy of the future. It is now becoming a crucial infrastructure similar to the electricity network and water supply. Therefore, it is important to maintain the stable development of future mobile communication network.

Future mobile networks require higher and higher data rates that enable different types of information exchange. With the current development trend, future mobile networks will consume significantly large amount of electricity, which in turn increase CO2 emission. The huge electricity consumption is not only a problem of cost for the mobile operators, but also an environmental problem. An energy efficient mobile network infrastructure that can also provide higher data rates to satisfy the future needs is essential.

This project aims to investigate this problem and develop novel techniques and schemes for future Green Heterogeneous Networks, which are both energy and spectral efficient. Successful completion of this project has the potential to have a real impact on the community. Not only will it benefit the research community and mobile operators, it will also have a positive impact on the environment. Moreover, a stable and reliable high speed network of the future is a crucial platform for future economic growth. Finally, a greener future network provides better and cheaper connections, which could bridge the digital divide in the nation and allow better social cohesion.