Interference Reduction Scheme for Femtocell Ultra-Dense-Network: Concept and Research Challenges

Abstract

_{In recent times, the demand for mobile broadband communications has increase exponentially due to the creation of new multimedia applications. To cater for this trend, dense deployment of cellular networks with aggressive frequency reuse patterns has been proposed. In this regard, densification of femtocells is a promising concept to meet growing mobile service requirements and for sustainability of users’ Quality of Service (QoS). However, an ultra-dense network (UDN) faces serious interference problems. One of this is the Inter-Cell Interference (ICI) caused by the simultaneous usage of the same spectrum in different cells. The problem becomes more complex when femtocells are located on cell edge area of macrocell. ICI reduces system throughput and network capacity, and has a negative impact on cell-edge users. Therefore, reducing the effects of interferences is an important issue in UDN. Hence, a critical issue arises: are conventional reduction scheme still effective to tackle the interference in UDN? To shed light on the problem, this paper provides a comprehensive survey of the methods for reducing interference in femtocell UDN. This survey aimed to provide a concise introductory reference for early researchers in the development of interference reduction scheme in femtocell. These methods are classified based on the nature of operation, investigated as to their strength and weaknesses, and then examined via several research studies which make use of each approach. Furthermore, technical challenges in each research study were identified. Finally some remarks for enhancing the research study were provided and potential direction for future research were highlighted.}