A New Pilot Assignment Scheme for Pilot Decontamination of Multi-Cell Massive MIMO Systems

In this paper, we aim to deal with the problem of pilot contamination in a multi-cell massive multiple input multiple output (MIMO) system. We make an effort to propose a pilot assignment strategy which leads to a low complexity optimization problem compared to the conventional algorithms. To this end, the problem of pilot assignment is formulated with discrete optimization variables, and a policy is devised to approximate the resultant problem by an optimization problem with continuous variables. Moreover, the outgoing problem is solved in an iterative construction in which the sequential convex programming (SCP) is employed. The numerical results demonstrate that the proposed scheme converges in very few iterations. Furthermore, the iterative algorithm exhibits an out-performance in comparison with the exhaustive search method in terms of complexity, for a negligible degradation in the signal-to-interference-plus-noise ratio (SINR).