Improving Energy Efficiency In Heterogeneous Network

In recent decades,environmental issues are becoming one of the major concerns for most human activities,including information communication technologies(ICT).This will surely influence future networking technologies,architectures and use practices.New approaches and methodologies are needed to assess and reduce the carbon footprint to what is commonly referred to Green Networks.The widespread deployment of small heterogeneous cellular networks introduces challenges and opportunities.Challenges come with reuse of the limited frequency resource to improve the spectral efficiency(SE),which always brought serious mutual interest and intracellular interference between or among small cell and macrocell.The opportunities refer to more potential chances of inter-and intratier and cooperation between small cells and macrocells.Energy efficiency(EE)will be a critical performance obligation for future green communications,especially when small cells are densely deployed to improve the quality of the user experience.We exploit the potential cooperation diversity to fight against the interference management challenges and EE.To capture the complex scrambling interaction and also coordination of behavior possible between small cells and macro cells,this thesis focuses on the energy efficiency of 2 tier heterogeneous networks(HetNets)in which massive multiple-input multiple-output(MIMO)is employed in the macrocell.We develop an analytical approach to examine EE of HetNets.For that,this project proposes a bargaining cooperative game(BCG)framework for EE and interference-aware power coordination in a dense small cell.In particular,a new adjustable utility function is used in the BCG to jointly cope with energy effectiveness issues.Using the framework BCG,we derive then Power coordination closed form solutions and also offer a common interference-aware power coordination mechanism with considerations both interference mitigation and energy savings.In addition,a simplified algorithm is presented to fight against the heavy signaling overhead,which is one of the important challenges in the scenario of a large deployment small cell.Finally,numerical results are presented to illustrate the effectiveness of the proposed common and simplified schemes and indicate that massive MIMO can achieve significant improvements of EE.