Self-organising heterogeneous cellular networks

The mobile communications market has experienced massive growth over the past 10 years, fuelled by the continuing take up of mobile services in the developing world and the exponential mobile data growth seen in the developed world. Current forecasts predict that today’s global mobile data traffic is set to rise by over 1000% by the year 2017 and in order to cope with this demand current 2nd and 3rd generation mobile networks are now evolving toward self-organising 4th generation heterogeneous networks in most markets. To address these capacity challenges this thesis firstly explores novel means to maximise the capacity of the existing macrocell network, therefore delaying the deployment of small cells and their associated costs. To do this it considers both higher order sectorisation and self-organising dynamic antenna tilt at the macrocell and shows through both detailed simulation and field trials that both techniques provide a reasonable capacity gain and therefore delay the need for the deployment of small cells. However, given current traffic forecasts, it is accepted that small cells will be required in the future and this thesis also considers the use of Self-Organising Network techniques to ensure that these small cells are located as close as possible to traffic hotspots to maximise their traffic and cost effectiveness. The thesis then goes on to show the effectiveness of low powered small cells to offload traffic from a co-channel macrocell layer and finally proposes a number of Self-Organising Network methods to maximise traffic offload from the macrocell layer onto a deployed small cell layer.