A Spectral Efficient and Fair User-Centric Spectrum Allocation Approach for Downlink Transmissions

Traditional spectrum allocation approaches assume that the intended users of BSs are treated equally, without consideration of their distances. Consequently, the efficiency of spectrum usage for downlink transmissions may suffer, because a BS may interfere with other BS transmissions; this would not happen if a proper transmission power is used. In this paper, we propose a user-centric spectrum allocation algorithm based on a physical interference model for downlink transmissions. In our approach, BSs set the power of an allocated spectrum band to ensure an effective transmission range for covering a group of intended users. A spectrum band is allocated to a BS if it can satisfy a group of users with the least amount of power possible (relative to other spectrum bands). Thus, after spectrum bands and transmission ranges are assigned, each BS owns several spectrum bands that can cover a group of users within varying transmission ranges. This approach leads to a higher rate of spectral reuse and improves system performance. In addition, the approach properly considers fairness issues among both users and BSs. Overall, simulation results show that our approach not only outperforms traditional BS-centric approaches by offering a 26% higher throughput in dense networks, but also provides fairer spectrum allocation.