Millimetre-Wave Air-Interface for 5G: Challenges and Design Principles

The extreme data rate requirements for 5G have pushed the mobile industry to exploit the large amount of available spectrum in the millimetre-wave (mm-wave) bands. mmMAGIC (Millimetre-Wave Based Mobile Radio Access Network for Fifth Generation Integrated Communications) is a European project aiming to develop novel radio access technologies for mobile communication at mm-wave frequencies. One of the main goal is the mm-wave air-interface design. In this paper, the key challenges for mm-wave air-interface design are first discussed. Afterwards, five key topics about air-interface are investigated in detailed regarding requirements/KPI’s and design principles. These five key topics are: Waveforms, channel codes and re-transmission schemes, frame structure and numerology, multiple access and duplexing schemes, and initial access schemes. The investigation in this paper not only provides insights into efficient design of mm-wave air-interface, but also help align various research activities in both industry and academia, paving the way for successful future 5G mobile communication networks. Keywords— Millimeter wave, 5G, above 6 GHz, beyond 6 GHz, air-interface, radio interface, waveform, channel code, retransmission scheme, frame structure, numerology, multiple access, duplexing schemes, initial access