5G Requirement and UDN

International Telecommunications Union (ITU) has defined the framework and overall objectives of the future development of IMT-2020 in light of the roles that IMT could play to better serve the needs of the networked society in the future [1]. There are three usage scenarios for 5G as shown in the following Fig. 2.1. 1. Enhanced Mobile Broadband (eMBB) addresses the human-centric use cases for access to multi-media content, services and data. This scenario will come with new application areas and requirements in addition to existing Mobile Broadband applications for improved performance and an increasingly seamless user experience. 2. Ultra-Reliable and Low Latency Communications (URLLC) use cases have stringent requirements for capabilities such as ultra-low latency and higher availability. Some examples include wireless control of industrial manufacturing or production processes, remote medical surgery, distribution automation in a smart grid, transportation safety, etc. 3. Massive Machine Type Communications (mMTC) use cases are characterized by a very large number of connected devices typically transmitting a relatively low volume of non-delay-sensitive data. Devices are required to be low cost, and have a very long battery life.