Early termination of repeated transmissions between terminal and base station in wireless communication system
Various embodiments provide methods whereby a terminal and a base station transmit and receive signals in a wireless communication system, and devices for supporting same. Comprised are the steps of: transmitting a physical uplink shared channel (PUSCH) to a base station; receiving, from the base station, hybrid automatic repeat request-acknowledgment (HARQ-ACK) information on the PUSCH before transmitting the PUSCH a number of times, the number of times being the number of repeated transmissions corresponding to the PUSCH; and determining whether or not to end the transmission of the PUSCH on the basis of the received HARQ-ACK information. Accordingly, the terminal can effectively control unnecessarily repeated transmission of uplink data, and the power consumption of the terminal can be reduced.
1. A method of communicating by a user equipment (UE) in a wireless communication system, the method comprising:
receiving scheduling information regarding scheduling for N repeated transmissions of a physical uplink shared channel (PUSCH), wherein N denotes a repetition number for the PUSCH transmissions;
starting the repeated transmission of the PUSCH based on the scheduling information;
receiving hybrid automatic repeat request-acknowledgment (HARQ-ACK) information on the PUSCH before the repeated transmission of the PUSCH has ended; and
determining whether to stop the repeated transmission of the PUSCH based on the HARQ-ACK information,
wherein a search space for receiving the HARQ-ACK information is configured by the UE based on the repetition number being identical to or larger than a predetermined value.
2. The method of claim 1 ,
wherein the HARQ-ACK information is obtained based on downlink control information (DCI), and
wherein the DCI is received on a machine type communication physical downlink control channel (MPDCCH) or a narrowband physical downlink control channel (NPDCCH).
3. The method of claim 2 , at least one state of the DCI are used to indicate HARQ-ACK feedback for the PUSCH.
4. The method of claim 2 ,
wherein based on the UE configured to operate in coverage enhancement (CE) mode A, a format of the DCI is determined as DCI format 6-0A, and at least one state of a resource assignment field included in the DCI format 6-0A is related to indicating HARQ-ACK feedback for the PUSCH, and
wherein based on the UE configured to operate in CE mode B, the format of the DCI is determined as DCI format 6-0B, and at least one state of a modulation and coding scheme (MCS) field included in the DCI format 6-0B is related to indicating HARQ-ACK feedback for the PUSCH.
5. The method of claim 2 , wherein a size of the DCI is identical to a size DCI format 6-0A or DCI format 6-0B.
6. The method of claim 2 , further comprising:
obtaining information on at least one of a duration of a HARQ-ACK feedback, a periodicity of the HARQ-ACK feedback, or a condition for performing the HARQ-ACK feedback from an uplink grant included in the DCI or a higher-layer message; and
performing the HARQ-ACK feedback based on the obtained information.
7. The method of claim 6 , wherein the condition for performing the HARQ-ACK feedback comprises at least one condition of a CE mode, an uplink repetition number, uplink transmission power, or an initial transmission or a retransmission.
8. The method of claim 1 , wherein the UE is configured to operate in frequency division duplex (FDD) or time division duplex (TDD).
9. The method of claim 1 , wherein the UE is configured to operate in a machine type communication (MTC) system or narrowband internet of things (NB-IoT) system.
10. The method of claim 9 , wherein based on the UE configured to operate in the NB-IoT system, at least one state of an MCS field and a subcarrier indication field included in DCI is related to indicating HARQ-ACK feedback for the PUSCH.
11. The method of claim 1 , wherein the HARQ-ACK information is received after the PUSCH is transmitted as many times as or more times than a predetermined ratio of the repetition number.
12. The method of claim 11 , wherein the predetermined ratio is determined based on at least one of: coverage enhancement (CE) mode of the UE, the CE level of the UE, reference signal received power (RSRP) of a predetermined reference signal, reference signal received quality (RSRQ) of the predetermined reference signal, or the scheduling information.
13. The method of claim 1 ,
wherein the HARQ-ACK information comprises HARQ-ACK information of a group related to a plurality of HARQ processes, and
wherein the HARQ-ACK information of the group is obtained based on bundling a predetermined number of HARQ processes among the plurality of HARQ processes into one group based on that a number of bits used to transmit the HARQ-ACK information is less than a number of the plurality of HARQ processes.
14. The method of claim 1 , wherein the predetermined value is related to a possibility of the PUSCH being available to be detected from a base station.
15. An apparatus of communicating in a wireless communication system, the apparatus comprising:
a transceiver; and
at least one processor coupled with the transceiver and configured to:
receive scheduling information regarding scheduling N repeated transmissions of a physical uplink shared channel (PUSCH), wherein N denotes a repetition number for the PUSCH transmissions;
start the repeated transmission of the PUSCH based on the scheduling information;
receive hybrid automatic repeat request-acknowledgment (HARQ-ACK) information on the PUSCH before the repeated transmission of the PUSCH has ended; and
determine whether to stop the repeated transmission of the PUSCH based on the HARQ-ACK information,
wherein a search space for receiving the HARQ-ACK information is configured by the at least one processor based on the repetition number being identical to or larger than a predetermined value.