Radio terminal and method

A method for a radio terminal, comprising:

• if the radio terminal is in a specific state different from an RRC connected state,
• receiving, by the radio terminal, multicast/broadcast data transmitted from a base station;
• autonomously determining, by the radio terminal, a transmission parameter to be used for transmitting feedback information on the multicast/broadcast data;
• and
• transmitting, by the radio terminal, the feedback information to the base station by using the determined transmission parameter, wherein
• the autonomously determining includes
• measuring received power of a reference signal received from the base station;
• comparing a value of the measured received power with a first threshold value and a second threshold value;
• and
• autonomously selecting as the transmission parameter, a timing advance value or a time-frequency resource associated with the first and second threshold values, when it is determined that the measured received power falls within a range of the first and second threshold values, and wherein
• the transmitting includes
• transmitting the feedback information using the timing advance value or the time-frequency resource selected on the basis of the comparison.

A system comprising a radio terminal and a base station, wherein

• the radio terminal includes
• a controller configured to perform a process of:
• receiving, if the radio terminal is in a specific state different from an RRC connected state, multicast/broadcast data transmitted from the base station;
• and transmitting feedback information on the multicast/broadcast data to the base station, wherein
• the controller is configured to autonomously determine a transmission parameter to be used for transmitting the feedback information and transmits the feedback information by using the determined transmission parameter, and wherein
• the controller is further configured to perform processes of:
• measuring received power of a reference signal received from the base station;
• comparing a value of the measured received power with a first threshold value and a second threshold value;
• autonomously selecting as the transmission parameter, a timing advance value or a time-frequency resource associated with the first and second threshold values, when it is determined that the measured received power falls within a range of the first and second threshold values;
• and
• transmitting the feedback information using the timing advance value or the time-frequency resource selected on the basis of the comparison.