A LTE Dual 32.47 us 3GPP TS Synchronous Dual Connectivity Connectivity 36.133 32.47 us Asynchronous Dual Connectivity 10.4 Evolution of the 5G Architecture As each generation of mobile network has evolved, the technology has also progressed and changed, which eventually leads to having to make changes in the architecture. For example, 3G/UMTS was a very successful implementation mostly based upon the WCDMA technology, while 4G/LTE was driven by the adoption of OFDMA. However, 5G is driven more by the use case than the technology itself, which needs a change in thinking about the architecture. The primary use cases can be classified into three major categories: eMBB (enhanced mobile broadband) and fixed wireless access (FWA): eMBB services are focused on broadband Internet access for the mobile user and are generally categorized as hu- man-centric communications. Having ever higher-speed and more-reliable connectivity while in motion has been the main driver for every successive mobile generation. The demand for more bandwidth with better coverage is increasing, which has resulted in a broad range of use cases with different challenges. These range from the use of dense hotspots to long-range, wide-area coverage and using both together as a combined system-hotspots are used to provide high data rates and high capacity in high traffic areas, while wide-area coverage solutions provide seamless mobility. Each one demands different performance and capacity re- quirements. High-speed access in densely trafficked areas (stadiums, offices, malls, and SO on), broadband connectivity everywhere (rural, suburban, highway, and SO on), and high-speed transport (trains, planes, and SO on) are the key market categories of eMBB services. mMTC (massive machine type communications): This is purely a machine-centric commu- nication segment, whereby a massive number of connected devices communicate over a very low-bandwidth connection. These connections are neither delay sensitive nor latency sensitive. It is likely that such machine