Mixed Waveform Numerology for Performance Enhancement in High Mobility Wireless Networks

In order to handle the ever-increasing requirements of mobile users, the design and operation of the physical layer of next-generation cellular networks demand high flexibility and efficiency. In addition, performance enhancement necessitates the support of a wide range of frequencies, intelligent dynamic use of the available spectrum resources, and the implementation of a number of types of waveform. Orthogonal Frequency Division Multiplexing (OFDM), and in particular its ability of Cyclic Prefix (CP) adaptation, appears unable to fulfil the requirements of the different types of services currently utilised by users. In this context, the parameters characterising the different types of waveforms, such as the number of subcarriers, subcarrier spacing (SCS) and slot duration, can be flexibly adapted to the current communication scenario, resulting in a reduction in latency and a significant improvement in user throughput. In this paper, the specific design peculiarities of mixed waveform numerology in relation to high-mobility communication environments characterized by Vehicle-to-Infrastructure (V2I) downlink communications are considered. The results demonstrate that the enhancement of network performance according to the specific channel conditions and level of interference, together with the trade-off between spectral efficiency and computational complexity, are the most important challenges in the design and practical implementation of the mixed waveform numerology concept.