Provided is a communication system, etc. with low latency and high reliability, under New Radio (NR). A communication system includes a communication terminal device, and a plurality of nodes configured to be connected to the communication terminal device for radio communication and to provide a split bearer for the communication terminal device. The communication terminal device is configured to perform uplink transmission to an uplink transmission node among the plurality of nodes. The uplink transmission node is determined by an uplink transmission node determination process in which a node that provides the uplink transmission from the communication terminal device with lower latency among the plurality of nodes is determined as the uplink transmission node.