ICon: Interference concentration for uplink in multicell OFDMA networks

In this work we propose a novel inter-cell interference coordination (ICIC) and resource allocation method. Our aim is to maximize the rate of the worst performing user in all cells. We solve the problem in two phases, inter-cell and intra-cell resource management: first we define an ICIC scheme called interference concentration (ICon) in order to manage resources across cells, then each cell independently performs resource allocation to its users while meeting the constraints imposed by ICon. Finally, we adapt the ICIC method in order to balance the performance achieved in neighboring cells. Differently than Soft Frequency Reuse (SFR), ICon assigns received interference power limits, or the Interference Power Profiles (IPPs) rather than transmit power limits. The IPP determines the interference level the cell tolerates on each band. The intuition behind this change is that the interference to a given cell can be concentrated on a small band, resulting in more efficient use of bandwidth. In the intra-cell resource management phase, each cell allocates power and sub-bands to its users given their location in the cell, maximizing the minimum rate such that the IPP of none of its neighboring cells is violated. In order to balance the performance across all cells we use gradient-like updates to IPPs of cells. Finally we simulate an LTE-like system and compare the performance of our method with reuse 1, static FFR and SFR with proportionally fair scheduling of users in each cell. Static ICon achieves 18% higher 5 percentile rate than reuse 1 which was the best of these methods. Adaptive ICon is found to converge almost immediately, and adds an additional 11% to this gain.