Terminal, base station, receiving method, and transmitting method

1. A terminal, comprising:

reception circuitry, which, in operation, receives control information on buffering for retransmission control; and

control circuitry, which, in operation, controls the buffering based on the control information, the control information including information indicating a priority of the buffering between a plurality of data, wherein,

the control circuitry, in operation, controls saving and discarding of data of the plurality of data in a buffer based on the information indicating the priority, wherein,

when there is no free space in the buffer, the control circuitry, in operation, overwrites, with received data, data in the buffer having a lower priority than the received data, and

when there is no data having the lower priority in the buffer, the control circuitry, in operation, discards the received data.

2. The terminal according to claim 1 , wherein

the control information includes information indicating the priority of data relating to new transmission and information indicating whether or not to perform combining processing on data relating to a retransmission request.

3. The terminal according to claim 1 , wherein

the control information includes information indicating a priority of the buffering between different data associated with same identification information related to a retransmission control process.

4. The terminal according to claim 3 , wherein

the different data associated with the same identification information is transmitted in different periods of a plurality of periods obtained by dividing a time interval corresponding to a propagation delay time of the data.

5. The terminal according to claim 4 , wherein

when the data transmitted in a first period is retransmitted in a second period different from the first period of the plurality of periods, the control information for the data retransmitted in the second period includes information indicating that combining processing is not performed on the data retransmitted.

6. The terminal according to claim 3 , wherein

the control circuitry, in operation, determines the identification information based on a time resource and an offset value to the time resource.

7. The terminal according to claim 6 , wherein

the offset value is determined based on a difference between a number of the time resource corresponding to data relating to new transmission and a number of the time resource corresponding to data relating to retransmission, and

the control information for the data relating to the retransmission includes information indicating that combining processing is performed.

8. The terminal according to claim 6 , wherein

the offset value is determined based on a difference between a number of the time resource of a first data saved in a buffer of the terminal and a number of the time resource of a second data associated with identification information same as the identification information associated with the first data, and

the control information for the second data includes information indicating that buffering of the second data is performed.

9. The terminal according to claim 1 , comprising:

transmission circuitry, which, in operation, collectively transmits response signals for a plurality of data, wherein

the control circuitry, in operation, switches between a first method of transmitting the response signals each including information indicating an error detection result for a corresponding one of the plurality of data and a second method of transmitting the response signals including information on erroneous data of the plurality of data.

10. The terminal according to claim 9 , wherein

the control circuitry, in operation, switches between the first method and the second method based on indication from a base station.

11. The terminal according to claim 9 , wherein

the control circuitry, in operation, selects one of the first method and the second method in which a number of transmission bits for the response signals is smaller.

12. A base station, comprising:

control circuitry, which, in operation, generates control information on buffering for retransmission control; and

transmission circuitry, which, in operation, transmits the control information, the control information including information indicating a priority of the buffering between a plurality of data, wherein saving and discarding of data of the plurality of data in a buffer is controlled based on the information indicating the priority, wherein,

when there is no free space in the buffer, the saving and discarding of data is controlled to overwrite, with received data, data in the buffer having a lower priority than the received data, and

when there is no data having the lower priority in the buffer, the saving and discarding of data is controlled to discard the received data.

13. A receiving method, comprising the following performed by a terminal:

receiving control information on buffering for retransmission control; and

controlling the buffering based on the control information, the control information including information indicating a priority of the buffering between a plurality of data, wherein saving and discarding of data of the plurality of data in a buffer is controlled based on the information indicating the priority, wherein,

when there is no free space in the buffer, the saving and discarding of data is controlled to overwrite, with received data, data in the buffer having a lower priority than the received data, and

when there is no data having the lower priority in the buffer, the saving and discarding of data is controlled to discard the received data.

14. A transmitting method comprising the following performed by a base station:

generating control information on buffering for retransmission control; and

transmitting the control information, the control information including information indicating a priority of the buffering between a plurality of data, wherein saving and discarding of data of the plurality of data in a buffer is controlled based on the information indicating the priority, wherein,

when there is no free space in the buffer, the saving and discarding of data is controlled to overwrite, with received data, data in the buffer having a lower priority than the received data, and

when there is no data having the lower priority in the buffer, the saving and discarding of data is controlled to discard the received data.