Relay radio terminal and radio terminal

A relay radio terminal comprising a controller configured to perform a process for relaying communication between a base station and a remote radio terminal in a mobile communication system, wherein

• the controller is configured to perform:
• a process of receiving system information broadcast from the base station;
• and
• a process of determining whether or not to relay information included in the system information to the remote radio terminal, wherein
• the controller is configured to determine to relay information included in the system information to the remote radio terminal when one of following conditions is satisfied:
• in a state where an end-to-end radio link between the relay radio terminal and the remote radio terminal is not established, the relay radio terminal determines to establish the end-to-end radio link;
• in a state in which the end-to-end radio link is established, the relay radio terminal detects an update of the system information;
• and
• in a state in which the end-to-end radio link is established, the relay radio terminal receives a system information relay request from the remote radio terminal.

A first radio terminal comprising a controller configured to perform a process for relaying communication between a base station and a second radio terminal in a mobile communication system, wherein

• the controller is configured to perform:
• a process of receiving a plurality system information (system information blocks, SIBs) broadcast from the base station;
• and
• a process of transferring part of system information among the plurality of system information to the second radio terminal via an end-to-end radio link with the second radio terminal, wherein
• the part of system information includes SIB type 18 which is system information on a side link direct communication of 3GPP (LTE) and SIB type 19 which is system information on side link direct discovery of 3GPP (LTE).