Resource Allocation Scheme for Energy Saving in Heterogeneous Networks

Energy efficiency in communication networks has received increasing attention in both industry and academia. In this paper, we investigate the energy saving issue in a heterogeneous network (HetNet), which is introduced to cellular radio networks to improve capacity and enhance coverage. A HetNet consists of base stations (BSs) with different transmission powers, resulting in systematic power control that is more complex than that in the conventional cellular networks. The main difficulty is addressing the mutual interference between different kinds of BSs. In this paper, we try to minimize the power consumption of an OFDM-based HetNet while satisfying all users' rate requirements, as well as considering the inter-cell interference. Our general problem formulation leads to a nonconvex optimization task that is generally hard to tackle. We derive a concave lower bound of user's achievable rate for a given power allocation, based on which an efficient iterative algorithm is developed to solve the formulated problem efficiently. Numerical results show that our proposed resource allocation scheme works well in different scenarios. The energy consumption of the cellular system is reduced dramatically compared to other schemes. Moreover, our proposed algorithm converges quickly and stably, showing great potential for applications.