Terminal device, base station device, and communication method
To efficiently control a cell by using a non-allocated frequency band or a shared frequency band. The terminal device includes a reception unit configured to receive a PDCCH, a transmission unit configured to transmit a PUSCH in a serving cell, and a CCA check unit configured to perform either first LBT for performing a CCA check a number of times based on a random number before a subframe for which a transmission of the PUSCH is indicated or second LBT for performing a CCA check only once. The terminal device switches between the first LBT and the second LBT, based on a prescribed condition.
1. A terminal device comprising:
reception circuitry configured to receive a physical downlink control channel including a downlink control information (DCI) format;
transmission circuitry configured to transmit a physical uplink shared channel (PUSCH) for a licensed assisted access cell scheduled by the DCI format; and
clear channel assessment (CCA) check circuitry configured to perform a listen before talk (LBT) procedure, the LBT procedure being a procedure that senses a channel to determine whether the channel is idle or busy before transmission of the PUSCH, wherein
the DCI format includes first information and second information,
the first information being 1 -bit information indicating either one type of a first type of the LBT procedure and a second type of the LBT procedure,
the second information associated with a window,
in case of the 1 -bit information indicating the first type of the LBT procedure, the CCA check circuitry is configured to
determine a value of the window based on the second information,
generate a random value as a number of repetitions of CCA check with an upper bound based on the value of the window, and
perform the repetitions of CCA check; and
in case of the 1 -bit information indicating the second type of the LBT procedure, the CCA check circuitry is configured to perform a single CCA check.
2. A method for a terminal device, the method comprising:
receiving a physical downlink control channel including a downlink control information (DCI) format;
transmitting a physical uplink shared channel (PUSCH) for a licensed assisted access cell scheduled by the DCI format; and
performing a listen before talk (LBT) procedure, the LBT procedure being a procedure that senses a channel to determine whether the channel is idle or busy before transmission of the PUSCH, wherein
the DCI format includes first information and second information,
the first information being 1 -bit information indicating either one type of a first type of the LBT procedure and a second type of the LBT procedure,
the second information associated with a window,
in case of the 1 -bit information indicating the first type of the LBT procedure,
determining a value of the window based on the second information,
generating a random value as a number of repetitions of CCA check with an upper bound based on the value of the window, and
performing the repetitions of CCA check; and
in case of the 1 -bit information indicating the second type of the LBT procedure,
performing a single CCA check.