Evolution of LTE and new Radio Access technologies for FRA (Future Radio Access)

摘要

The paradigm shift toward smartphones caused distinct traffic expansion in mobile networks. Indeed, the total amount of traffic in Japan is glowing nearly 1.8-fold in yearly basis during the past few years. To cope with this problem, many mobile operators are now speeding up their deployment of LTE/LTE-A. In this paper, current situation of LTE deployment in Japan, including area deployment and spectrum assignment are introduced. Then, the technical trend for further enhancement of LTE-A is presented based on the current standardization activities in 3GPP Rel.11 and Rel.12. Finally, the requirements and some expected technologies for the next generation mobile system, namely 5G or Future Radio Access (FRA), will be presented. Here, small cell deployment and its interwork with macro-cell is regarded as one of promising ways for increasing channel capacity while maintaining mobility support. As to radio access technologies, advanced interference mitigation and non-orthogonal multiple access (NOMA) are likely to be key issues for FRA. Initial evaluations of Massive-MIMO performance are also presented for clarifying the feasibility in the assumed scenario.