Multi-carrier cell structures with offset sectorization for heterogeneous networks

Traffic projections for the coming years indicate that the demand for wireless data is increasing exponentially, driven by new multimedia services and the wide availability of smartphones. A promising approach for providing additional required network capacity is the deployment of small cells in a heterogeneous network structure, which increases the spatial frequency re-use. However, the deployment of small cells into existing macrocellular networks can lead to interference and handover problems, particularly when re-using the frequency spectrum. In this paper, a novel configuration of the cellular network structure and frequency use for both macrocell and small cells is proposed to address these problems while maintaining high frequency re-use. Simulations for UMTS HSDPA show that the proposed multi-carrier heterogeneous network structure can increase the average user throughput of macrocells and small cells by 51% and 116% respectively, and the throughput of the worst 5th percentile by 213%, compared to a dedicated carrier reference deployment. The proposed solution also significantly outperforms partial frequency re-use deployments.