Maximizing spectral efficiency for cell edge users in LTE small cell network

Cellular communication systems especially LTE mandates the use of a simple and effective downlink power control of signals for controlling randomly dispersed user´s throughput, interference, connectivity link. Users at the cell edge experience low throughout due to packet retransmission, and packet drop scenario. Due to the above problems, the operator loses revenue from the cell edge users due to poor usage of the spectrum. In this paper we propose a novel downlink optimal power allocation scheme (DOPAS) which maintains a constant cell edge spectral efficiency of a LTE cell for a given user density distribution and traffic type. DOPAS can be used to enhance the cell edge throughput without compromising the throughput of the users present closer to the eNodeB. DOPAS uses the convex optimization method in allocating right power control for both cell edge and near cell users and thus guaranteeing cell edge spectral efficiency. The cell edge throughput using the proposed algorithm is compared against the homogenous power allocation scheme where the cell power is uniformly distributed across the resource blocks of the scheduled users. Results showed that using DOPAS, there is a significant rise in cell edge throughput as compared to the modified homogeneous power allocation scheme. The improvement varied from 20-80% depending on the number of users present in near cell and cell edge region resulting in maintaining an operator defined cell edge spectral efficiency.