Optimal Radius of Exclusion Zone for Dense Cognitive Small Cell Networks

Network densification via small cell deployments can enhance the network capacity in a cost-effective manner. Co-tier and cross-tier interferences form barriers to boost the network performance. In this paper, an interference coordination scheme with the aid of cognitive radio is proposed for dense small cell networks. Based on the theory of stochastic geometry, the network spectral efficiency is derived as a function of the radius of exclusion zone. Furthermore, the optimal radius of exclusion zone that maximizes system spectral efficiency is obtained by one-dimension searching. Simulation results show that the proposed interference coordination scheme with the optimal exclusion zone outperforms the existing ones in terms of system spectral efficiency.