Opportunistic interference alignment for three‐tier partially connected heterogeneous networks

Abstract

Summary With the expected increase in the number of connected devices, heterogeneous networks (HetNets) technology has gained great attention in next generation wireless networks. The deployment of such low power nodes in the same geographical area and using the same allocated frequency introduces significant interference among different nodes in the network. In this paper, we propose a two‐stage opportunistic interference alignment (OIA) scheme for the three‐tier downlink HetNet that targets user scheduling along with mitigating intertier and intratier interference signals. Two cascaded precoding matrices as well as two cascaded postcoding matrices are used to perform the two‐stage interference alignment (IA) operation. The outer precoding/postcoding matrix pair are designed using the rank‐constrained rank minimization (RCRM) to minimize the interference among the users associated to the same tier. Simulations show that the proposed scheme outperforms other conventional schemes in terms of the sum rate and the sum achieved degrees of freedom (DoF).