Performance Evaluation of 5G in VHF Band for Super-large Coverage Communication Systems

In the 6th-generation mobile communication (6G) system, massive simultaneous connections are required, including all “things” such as sensors, meters, and monitors, in addition to ordinary users. To realize this large number of simultaneous connections, it is necessary to provide stable communication over a wide area. In this study, we propose the utilization of the VHF band (200 MHz) for 5G new radio (NR), which is even lower than the frequency of 450-6000 MHz, defined as the frequency range 1 (FR1) in 3GPP. Since the VHF band has a longer wavelength than the microwave band in which the 5G-NR currently operates, the transmission distance of the signal from the base station increases. However, delay waves of over 20 μs were received in rural areas. These waves cause an inter-symbol interference and deteriorate the transmission performance. Therefore, the parameters of the 5G-NR may be adapted to the radio wave propagation environment in the VHF band. Since 5G-NR uses a strong error-correcting code such as low-density parity-check (LDPC) code and the frame structure can correspond to various radio wave propagation path characteristics, we may not need to change any parameters. Herein, the transmission performance of 5G-NR in the VHF band is evaluated via computer simulations, and it is shown that the required block error rate (BLER) can be achieved even when QPSK, 16QAM, and 64QAM are utilized without changing the parameters of 5G-NR and that the transmission range can be achieved to 20 km.

I. Introduction

The 5th-generation mobile communication (5G) system, which realizes high-speed and high-capacity communication with ultra-low latency and 100,000 units per km² simultaneously, has started in 2020, and it is being utilized not only for ordinary users but also for social infrastructure and so on [1]. Research and development of the 6th-generation mobile communications (6G) system, which is supposed to be serviced after 2030, has been actively progressing. The 6G system requires the realization of a large number of simultaneous connections that are 10 times larger than 5G. In particular, a large number of simultaneous connections are required not only for ordinary users but also for IoT that provide communication functions for all kinds of “things” such as sensors, meters, and monitors. The transmission rate required for IoT devices varies. For example, regarding automated driving, broadband information exists, such as moving images. However, the data rate of most control information is low. By transmitting the control information as widely as possible, more stable automatic driving can be realized.