A multiple region reverse frequency allocation scheme for downlink capacity enhancement in 5G HetNets

To cope with the data surge problem and to enhance the coverage of existing cellular systems, heterogeneous networks (HetNets) are deployed in hierarchical manner, comprising of macrocells and overlaid femtocells. A novel interference mitigation technique of Reverse Frequency Allocation (RFA) scheme is introduced, which provides intercell orthogonality by dividing the cell into spatial regions and optimally allocating the frequency resources. RFA enhances the data rates of downlink femto users by eliminating the cross-tier interference from macro base station (MBS). In this paper, we extend the multiple region RFA scheme in multi-cellular network to further mitigate the impact of interference in the adjacent cells. In addition, we also develop a hybrid RFA scheme that merges the benefits of different RFA schemes in terms of large bandwidth and limited interference to achieve higher data rates. Simulation results show that the modified RFA (M-RFA) schemes exhibit superior performance as compared to the conventional RFA schemes in terms of user-fairness and improved sum capacity. For the evaluation of system performance, several metrics such as outage probability, sum rates and outage capacity have been analyzed for satisfying the constraint of minimum capacity requirement of cell edge users.