ecause of their use of high- frequency, gigahertz spectrum bands and the increases in the amount of data and video traffic. In addition to the high costs of operating cell sites, mobile providers manage huge wired networks made up principally of fiber-optical cabling and some microwave links. These links connect RAN traffic to: Backhaul between the evolved packet core, which is a mobile carrier's data center, and cell sites Other cells in the mobile network Other mobile networks The Internet Enterprise broadband networks Heterogeneous Networks-Architecture for Densely Trafficked Areas Heterogeneous Networks (HetNets) is a 3GPP architecture that defines the way small cells connected to each other support mobile networks in areas with dense pockets of traffic. It is a network made up of a mix of different types of base stations and antennas, thus the term heterogeneous networks. Often these are in downtown areas in cities with large numbers of pedestrians, office buildings and apartments. HetNets are suited to handle the increasingly bandwidth- intensive traffic such as streaming video and online games. HetNets were developed to add capacity for the growth in data and video usage, not to expand coverage. HetNets are used in both LTE and 5G networks. Capacity is important at the edge of cells where performance may degrade as traffic is handed off between cells. The main issue at the cell edge are delays when calls are handed over to adjacent cells. HetNets are www.TechnicalPDF.com additionally suited to the increasing use of high- frequency gigahertz spectrum used because gigabit spectrum is capable of handling increased traffic. However, gigabit frequencies only travel short distances before fading, thus more small, low-powered cell sites are needed to support traffic over gigahertz spectrum. Characteristics of HetNets HetNets are made up of large numbers of small cells controlled by larger macro cells to which they are connected wirelessly or by fiber-optic cabling. HetNets' low-powered cells have smaller antennas