Exclusion Zone Assisted eICIC in Massive MIMO Enabled Cognitive HetNets

Abstract

In a massive MIMO-enabled cognitive HetNet, a multi-user massive MIMO macrocell is underlaid with dense cognitive small cells. Then, a plenty of exclusion zones (EZs) are formed around co-scheduled macrocell users. Applying enhanced inter-cell interference coordination (eICIC) in each EZ separately, we propose an EZ-assisted eICIC scheme which arranges a customized eICIC configuration for each EZ independently to others. The proposed scheme can overcome potential weaknesses of current eICIC and that of cognitive HetNets. Then, the EZ-assisted eICIC configuration problem is formulated as a general optimization problem, which maximizes overall weighted sum rate of the network. Since the problem is intractable, a cluster segmentation approach is, therefore, proposed to convert the problem into a feasible version. Furthermore, we design an iterative multi-user scheduling-based algorithm to solve the problem. Numerical results demonstrate that the proposed EZ-assisted eICIC scheme significantly outperforms eICIC and further eICIC in dense HetNet.

Keywords

• Cognitive HetNets
• cross-tier interference
• exclusion zone
• eICIC
• FeICIC
• massive MIMO