No abstract

No abstract

Clustering is a promising interference mitigation scheme in dynamic TDD systems. However, most previous works just took large-scale path loss or coupling loss as criteria of the clustering schemes, thus the throughput performance would be limited by the varying traffic requirements among different small cells within one cluster. In this paper, a novel dynamic clusterbased Interference Mitigation and Traffic Adaptation (IMTA) scheme is proposed and evaluated with dense deployment of small cells (SCs). Firstly, a new clustering criterion named Differentiating Metric (DM) is defined. Based on the defined DM value, a DM matrix is formed and further presented by a clustering graph. In the clustering graph, the dynamic clustering strategy is mapped to a MAX K-CUT problem, which is addressed in polynomial time by a proposed heuristic clustering algorithm. Furthermore, the system level simulation results demonstrate a promising improvement on uplink traffic throughput (UTP) in our proposed scheme compared with traditional clustering schemes.

In LTE-Advanced (LTE-A) and beyond networks, deploying complementary small cells on an existing macro layer is recognized as an attractive solution to improve the network capacity and provide seamless broadband services in local areas. However, existing cell discovery mechanism is tailored for homogeneous networks (macro only). User Equipment (UE) can't energy-efficiently detect the small cells on a dedicated carrier or maximally exploit the offloading opportunities provided by such heterogeneous deployments. In this paper, we propose a Predictive Connection time based Inter-frequency Measurement (PCIM) solution to cope with the problems. With the aid of the positioning results, the small cell connection time is derived, both user velocity and moving direction are taken into account. Using 3rd Generation Partnership Project (3GPP) LTE-A Heterogeneous Network (HetNet) mobility evaluation methodology, the proposed PCIM scheme is compared with some currently standardized techniques. Simulation results provide insights on the small cell discovery schemes in terms of energy efficiency and small cell usage efficiency, and demonstrate the benefits of the proposed PCIM scheme over the other alternatives.