A Distributed Taxation Based Rank Adaptation Scheme for 5G Small Cells

The further densification of small cells impose high and undesirable levels of inter-cell interference. Multiple Input Multiple Output (MIMO) systems along with advanced receiver techniques provide us with extra degrees of freedom to combat such a problem. With such tools, rank adaptation algorithms allow us to use our antenna resources to either exploit multiple spatial streams in low interference scenarios, or suppress interference in high interference scenarios. In this paper, we propose and evaluate an interference-aware distributed rank adaptation algorithm. The concept behind our approach is to discourage the choice of transmitting with multiple spatial streams in highly interfered scenarios, and to exploit and encourage the usage of multiple spatial transmission streams in low interference scenarios. We show that our proposed algorithm can be adjusted to preserve and guarantee a good outage performance, while providing the benefit of higher average throughputs, in both low and highly interfered scenarios, when compared to fixed rank configurations, and distributed selfish schemes.