D beamforming/ FD-MIMO specs LTE MTC Enhanced D2D 5G technology SI(s) 5G work items 5G requirements SI >6 GHz channel model SI Figure 17.7 Expected 3GPP timeline for LTE-A evolution and the introduction of 5G LTE Small Cell Optimization started in parallel to the study phase aiming for such 'Phase 1 5G'. Further needs and use cases reflected in Figure 17.2 would then be addressed later, including evolution of the core network for those use cases. This is expected to be the key item in the 3GPP TSG RAN 5G workshop in September 2015 to define the 3GPP roadmap on 5G [9]. 17.7 Conclusions In the previous sections, we have covered the expectations for the further LTE-Advanced evolution beyond 3GPP Rel-12 as well as the first stages and expected timeline of the 5G systems. The process and timeline for 5G is already in place, and the work for detailing out the vision, use cases and requirements is well on the way, but how the 5G system will finally look like will be known with certainty only in the years to come. However, it is already possible to say a few things about it. 5G is needed to answer the ever-growing data demands and to enable mobile communica- tions on higher frequency bands in which LTE is not very suited. The big focus on peak data rates and extending the band access may lead to confusion that 5G is about small cells on high-frequency bands only, when that is just one, albeit important aspect of 5G. 5G will unlock the potential of the higher frequency bands above 6 GHz, but at the same time for wide area coverage and M2M use, 5G will find itself to the more traditional lower cellular frequency bands as well. The access scheme for 5G is still under research, but dynamic TDD based on OFDMA (on bands below 6 GHz and up to a few tens of gigahertzs) and DFT-generated single carrier waveforms (on several tens of gigahertzs) coupled with massive MIMO, pencil beamforming and enhanced spectrum flexibility emerge as strong candidates for the new access schemes. It is also important to keep in mind that whatever te