As Charles Darwin believed ‘’It is not the stongest of the species that survive, nor the most intelligent, but the one most responsive to change”. Based on that theory every aspect and application that help us communicate with each other is being under construction due to the continuously growing needs we have as network technology gives us more possibilities and functions. Evolution is the secret for the next step and this is the essence of impact left behind by every technology. We have all seen the innovations in the field of Communications from Telegraph invented in 18th Century to 5G Communications. Nowadays, the wireless communications had changed radically in order to cover all kind of digital life needs, such as communication with each other or entertainment. To understand how the mobile communications work we have to deeply have a look, in this thesis, at how the cellular networks work and evolved through the years. After that we observe the interference impact on the cellular networks and how technologies like OFDM manage more efficiently the wireless resources. Because of the increasing needs for higher capacity we study the HetNets and future implementations of networks such as Uplink and Downlink Decoupling, which is the main topic of this thesis. From the beginning of cellular network studies these two connections were coupled. We are reasearching the advantages and the benefits of using this decoupled scenario in future network deployments, that could radically change the cellular network status quo. Lastly, we make simulations in order to prove the advantages of Decoupling associations over the coupled ones.