Study of the Multichannel Access Method in Coexistence Scenarios of Two New Radio Unlicensed Operators

The use of multichannel transmissions significantly improves the performance of New Radio Unlicensed (NR-U) networks. The NR-U specification describes a multichannel access method using which a base station performs a backoff procedure only in one channel called the primary channel. Other channels are called secondary channels and sensed immediately before data transmission. In coexistence scenarios of several NR-U operators in the same frequency band, this may result in asymmetrical distribution of channel resources among operators. In this paper, with simulation, different options of selecting primary and secondary channels of two operators are studied. Normalized throughput and equality of channel resources sharing are estimated. Based on the results, an enhancement of the multichannel access method is proposed to provide equal distribution of channel resources between operators and high total throughput.