TITLE: Energy and Spectral Efficiency in Next Generation Cellular Networks

In this talk, we will first discuss the importance of energy efficiency (EE) in nextgeneration multi-cell heterogeneous networks (HetNets). We will than discuss the tradeoff of EE and and spectral efficiency (SE) in multi-cell HetNets. Our objective is to maximize both EE and SE of the network while satisfying the rate requirement of users. We use multi-objective optimization techniques to define the objective function. We propose a three-stage algorithm. First, we select the cell-center radius for the fractional frequency reuse (FFR) method. Second, we assign the frequency resources to satisfy the rate requirements of users and maximize the objective function. Third, the power allocation subproblem is solved by using the Levenberg-Marquardt method. Our numerical results show that a Pareto-optimal solution exists for EE and SE. We present results for different rate constraints.