carrier Load Connectivity WI Superposition TX SI Distribution of UEs WI Perf. enhancements for Enhanced Signalling for high speed scenario SI Indoor Positioning WI Dual Connectivity Inter-eNB CoMP WI enhancements WI BS AAS req. WI LTE based V2X services Multi-RAT Joint Extended DRX WI Coordination SI UE TRS/TRS req. WI Narrowband loT (NB-IoT) Dedicated Core Interference Mitigation Latency Reduction SI for DL Ctrl. Ch. WI Networks WI Application Specific Congestion Control WI Network Assisted Synch Study item Work item Figure 17.1 Release 13 topics for LTE-advanced evolution LTE Small Cell Optimization 17.3 Towards 5G Work is on-going in ITU-R [1] for the IMT-2020 [2], more commonly known as 5G. The process in ITU-R will define requirements for the next-generation system for International Mobile Telephony, similar to the IMT-2000 process for 3G and IMT-Advanced for 4G. The requirements will then be processed in 3GPP and other organizations along with their internal requirements as a pretext for developing a system that meets the defined targets. Key technology companies and specific forums have already set out their visions for the next-generation system and in some cases are fairly detailed in their view of what the use cases and requirements are, as reflected, for example, in [3] (Figure 17.2; Table 17.1). While the requirements are still being developed in ITU-R, the following key areas related to the user experience and system performance can already be seen as emerging as the requirements with the detailed values still to be concluded in ITU-R side, but also addressed in [4]: Peak data rates in the order of 10 Gbps or more and expected minimum user-experienced data rate across the area of deployment, which is likely to be in the order of 100 Mbps, with an example value of 300 Mbps used in [3]. Traffic density in terms of gigabits per second in a given area, with technology supporting 1 Tbps/km2 or higher traffic density in specific confined areas. Peak data rate User-experienced (Gbps) data rate (Mbps) 100-10