Performance Evaluation of Cell-Edge Femtocell Densely Deployed in OFDMA-Based Macrocellular Network

The demands for the better quality of services and system capacity are continuously increasing for the cellular wireless communication industry. Femtocell is a promising solution to enhance the capacity and coverage of cellular networks. Femtocell densely deployed in existing conventional macrocell or microcell of cellular networks which is known as Ultra Dense Networks (UDNs) is one of key technologies for 5G and beyond wireless cellular network. One crucial problem of UDNs is co-tier interference (femtocell to femtocell interference) and cross-tier interference (femtocell to microcell/microcell interference) that can cause performance degradation of the network. This paper investigates the co-tier and cross-tier interferences of UDNs in uplink transmission in which femtocells are located on the edge of microcell cellular networks. By this scenario, thus the users on the cell-edge of the neighborhood macrocells can contribute severe interferences to the evaluated cell-edge femtocells. And then, this paper evaluates the performance of aforementioned network scenarios through simulation experiments. Signal to Interference Noise Ratio (SINR) is used as a performance parameter. Two UDNs network scenarios are evaluated in the simulation, first scenario is 100 femtocells deployed randomly within the whole coverage area of macrocell and the second one is 100 femtocells deployed in outer area of macrocell which represents cell-edge of macrocell. The distribution of SINR of these two scenarios are measured in the simulation. The simulation results show that the performance degradation is much by cell-edge users of neighborhood macrocells (achieving 20%) which become important results for the further study in mitigating the interference problems of cell-edge femtocells in the UDN.