optimizing spectrum-energy efficiency in wireless networks
The popularity of smart mobile devices has brought significant growth of data service for mobile service providers. Very often, mobile users of data service are charged based on the amount of data used. With the increasing revenue, mobile operators are also facing the increasing operation cost due to the high energy consumption. Meanwhile, as the access to spectral resource is limited, increasing spectrum efficiency is an economic incentive for operators alike. However, we are faced with the dilemma that focusing only on reducing energy consumption might incur the cost of decreasing spectrum efficiency. In this paper, we study the spectrum-energy efficiency enhancement problem by way of jointly considering the mechanisms of cell zooming, sleep mode and user migration. To gain the benefits economically, we formulate an optimization framework into an integer linear program which is solvable by CPLEX to maximize spectrum and energy efficiencies jointly as well as to meet the minimal traffic demand by associated users in multicell/multi-user networks. To avoid high computation time, a heuristic algorithm is proposed to efficiently solve the formulated problem. Numerical analysis through case studies demonstrates the energy saved and efficiency improvements and the comparison between the proposed heuristic algorithm against the optimal solutions.