Downlink Intercell Interference Behavior in Heterogeneous Networks

Continuing exponential surge in mobile data traffic demands the need for heterogeneous networks (HetNets) in which low-power nodes small cells such as picocells and femtocells coexist with macrocells. Specifically, Femtocells are rapidly emerging as a promising indoor solution that provides excellent indoor coverage, high data rate service, and moreover, offloads the traffic of the existing macrocell networks that are moving rapidly towards congestion. Due to closed access mode operation of small cells and independent sharing of radio resources among them, the inter cell interference (ICI) management is a highly challenging one. This kind of ICI severely affects the Quality of Service achieved by the victim users and hinders the user throughput maximization. For maximizing the user throughput, ICI management can be effectively accomplished by ICI coordination (ICIC) techniques and particularly in HetNets, the self-organization of small cells using intelligent learning such as Reinforcement learning, Fuzzy Q-learning, and deep learning methods have been investigated in many recent works for ICIC. At first, this paper presents an overview of downlink interference scenarios in femtocell networks and then presents the simulation results that have been obtained using LTE-A Femto-Macro simulator, which clearly exemplify the rigorousness of interference that claims the need for ICIC schemes. Finally, it highlights the importance of intelligent learning methods to solve the said ICIC problem in the wireless networks.