ation-centric methodologies were needed to model this growth for the 5G era. ITU-R, in a Recommendation (ITU-RM.2083) describing its vision for 5G framework and objectives, specifies several Key Performance Indicators (KPIs) as part of outlining future networks' Technical Performance Requirements (TPRs). These include, for instance, peak 2.3 Spectrum Highest growth forecast in M.2243 Lowest growth forecast in M.2243 x80 (75% value of the estimated range) x44 (25% value of Estimated the estimated range) growth range Extrapolated 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 Figure 2.5 IMT-Advanced spectrum estimation, 2013. (Source ITU-R). and average data rates, latency, and spectral efficiency. These values, generally presenting aggressive leaps compared with previous generations, would then need to be supported by the radio interfaces of 5G systems. A new approach based on requirements of various new applications and defined TPRs was chosen. This new approach is based on the simple principle that all other aspects held constant, a system targeting an application requiring a 100 Mbps user data rate would require 10 times more spectrum than a system targeting another application requiring only a 10 Mbps user rate. A simple equation was used (Eq. (2.1)), assuming full-buffer traffic, to calculate the bandwidth B (in Hz), expressed as a product of the required user/device data rate D (in bits/s) and the number of simultaneously served users/devices (N) in the cell, divided by the spectral efficiency S (in bits/s/Hz). =(DxN)/S (2.1) It was anticipated that different TPR values would result in different spectrum require- ments. Table 2.1 (ITU-R WP5D) demonstrates the outcome of one such calculation for three different types of TPRs. Example 1 is based on cell-edge user data rate targets in M.2083 using Eq. (2.1). Example 2 additionally assumes sample deployments in two dif- ferent environments. Example 3 considers the combined impact of latency and end-to-end data delivery. The extent of spectrum requirements, ma