Method of fast-retransmitting uplink data in wireless communication system and apparatus therefor
The present application relates to a method performed by a terminal for transmitting uplink data (UL data) in a wireless communication system supporting a low latency service, the method comprising the steps of: receiving a UL grant for transmitting initial data from a base station; transmitting the initial data to the base station on the basis of the received UL grant; receiving, from the base station, non-acknowledgement (NACK) for the transmission of the initial data and a simple UL grant comprising resource information related to the retransmission of the initial data; and performing the retransmission of the initial data on the basis of the received simple UL grant.
1. A method for transmitting, by a user equipment (UE), uplink (UL) data in a wireless communication system that supports a low latency system, the method comprising:
receiving, from a base station, a first UL grant for initial data
transmitting, to the base station, the initial data based on the first UL grant;
generating a transport block related to a retransmission of the initial data;
receiving, from the base station, a negative acknowledgement (NACK) for the initial data and a second UL grant,
wherein the second UL grant includes a position of a physical resource for the transport block;
mapping the transport block to the position of the physical resource based on the second UL grant; and
transmitting, to the base station, the transport block on the physical resource.
2. The method of claim 1 ,
wherein the second UL grant further includes at least one of a subframe offset (SF_offset) field representing a subframe (SF) offset from a SF on which the base station transmits the second UL grant, a hybrid automatic repeat request (HARQ) process ID (HARQ PID) field representing a HARQ process ID that corresponds to retransmission data, a RBSTART field representing an index of a resource allocation start resource of the transport block or a redundancy version (RV) field representing a version of redundancy in HARQ of incremental redundancy scheme.
3. The method of claim 1 , wherein the NACK is received through a Physical Hybrid-ARQ Indicator Channel (PHICH), and
wherein the second UL grant is received through a Physical Downlink Control Channel (PDCCH).
4. The method of claim 1 , wherein when the initial data is data having a fixed size, a first format of the first UL grant is same as a second format of the second UL grant.
5. The method of claim 4 , further comprising transmitting, to the base station, control information representing whether the initial data is general data or data of a fixed size.
6. The method of claim 5 , wherein the control information is transmitted to the base station through a scheduling request (SR).
7. A method for transmitting, by a base station, uplink (UL) data in a wireless communication system that supports a low latency system, the method comprising:
transmitting, to a user equipment (UE), a first UL grant for initial data;
receiving, from the UE, the initial data;
transmitting, to the UE, a second UL grant and a negative acknowledgement (NACK), when decoding of the received initial data is failed,
wherein the second UL grant includes a position of a physical resource for a transport block related to a retransmission of the initial data; and
receiving, from the UE, the transport block on the physical resource.
8. The method of claim 7 , wherein the second UL grant further includes at least one of a subframe offset (SF_offset) field representing a subframe (SF) offset from a SF for transmitting the second UL grant to the UE, a hybrid automatic repeat request (HARQ) process ID (HARQ PID) field representing a HARQ process ID that corresponds to retransmission data, a RBSTART field representing an index of a resource allocation start resource of the transport block or a redundancy version (RV) field representing a version of redundancy in HARQ of incremental redundancy scheme.
9. The method of claim 7 , wherein the NACK is transmitted through a Physical Hybrid-ARQ Indicator Channel (PHICH), and
wherein the second UL grant is transmitted through a Physical Downlink Control Channel (PDCCH).
10. The method of claim 7 , wherein when the initial data is data having a fixed size, a first format of the first UL grant is same as a second format of the second UL grant.
11. The method of claim 10 , further comprising receiving control information representing whether the initial data is general data or data of a fixed size.
12. The method of claim 11 , wherein the control information is transmitted to the base station through a scheduling request (SR).
13. A user equipment (UE) transmitting uplink (UL) data in a wireless communication system that supports a low latency system, the UE comprising:
a radio frequency (RF) unit for transmitting and receiving a radio signal; and
a processor functionally connected to the RF unit,
wherein the processor is configured to perform:
receiving, from a base station, a first UL grant for initial data;
transmitting, to the base station, the initial data based on the first UL grant;
generating a transport block related to a retransmission of the initial data;
receiving, from the base station, a negative acknowledgement (NACK) for the initial data and a second UL grant,
wherein the second UL grant includes a position of a physical resource for the transport block;
mapping the transport block to the position of the physical resource based on the second UL grant; and
transmitting, to the base station, the transport block on the physical resource.