Method of processing HARQ by considering measurement gap
A HARQ processing method is disclosed, by which a measurement gap is considered. In particular, as a terminal performs an inter-measurement operation, if HARQ feedback information reception is impossible, the terminal determines HARQ feedback information, which is not received for a next HARQ operation, as ACK or NACK by itself and is then able to perform the next HARQ operation. Specifically, in case that the terminal operates by determining the non-received HARQ feedback information as ACK, a corresponding uplink signal keeps being stored in an HARQ buffer and can be retransmitted according to a new UL grant reception from a base station.
1. A method for a HARQ (hybrid automatic repeat request) operation processed by a terminal in a mobile communication system, the method comprising:
receiving an uplink grant signal from a base station;
transmitting a specific uplink signal to the base station based on the uplink grant signal;
determining whether there is a measurement gap for the terminal not to perform at least one of uplink and downlink communications at a timing of receiving feedback information for the specific uplink signal transmission from the base station, wherein the feedback information comprises acknowledgement (ACK) and non-acknowledgement (NACK)for the specific uplink signal transmission; and
setting the feedback information to the ACK when the measurement gap is set at the timing of receiving the feedback information and thus whereby the transmission of the feedback information from the base station is not scheduled at the timing as the result of the determination.
2. The method of claim 1 , wherein the terminal keeps the specific uplink signal in a HARQ buffer, even when the terminal sets the feedback information to the ACK.
3. The method of claim 2 , further comprising:
receiving an additional uplink grant signal for the specific uplink signal from the base station; and
retransmitting the specific uplink signal which has been kept in the HARQ buffer from the terminal.
4. The method of claim 1 , further comprising:
performing at least one of an intra-frequency measurement, an inter-frequency measurement and an inter-RAT mobility measurement during the measurement gap.
5. The method of claim 1 , wherein the HARQ operation is a synchronous HARQ operation.
6. A terminal to perform a HARQ (hybrid automatic repeat request) operation in a mobile communication system, the terminal comprising:
a receiving module receiving an uplink grant signal from a base station;
a transmitting module transmitting an uplink signal to the base station based on the uplink grant signal;
a measurement module performing a measurement operation and not performing at least one of uplink and downlink communications during a prescribed measurement gap; and
at least one HARQ process module configured to manage the HARQ operation of the terminal,
wherein the at least one HARQ process module is configured to determine whether a measurement gap is set at a timing of receiving feedback information for a specific uplink signal transmission from the base station and to set the feedback information to an acknowledgement (ACK) for the specific uplink signal transmission, when the measurement gap is set at the timing of receiving the feedback information and thus the transmission of the feedback information from the base station is not scheduled at the timing as the result of the determination, wherein the feedback information comprises the ACK and a non-acknowledgement (NACK) for the specific uplink signal transmission.
7. The terminal of claim 6 , wherein each of the at least one HARQ process module is associated with a HARQ buffer, and
wherein when a specific HARQ process module among the at least one HARQ process module sets the feedback information to the ACK, the specific HARQ process module is configured to keep the specific uplink signal in a specific HARQ buffer associated with the specific HARQ process module.
8. The terminal of claim 7 , wherein when the receiving module receives an additional uplink grant signal for the specific uplink signal from the base station, the specific HARQ process module is configured to retransmit the specific uplink signal which has been kept in the specific HARQ buffer via the transmitting module.
9. The terminal of claim 6 , wherein the measurement module is configured to perform at least one of an intra-frequency measurement, an inter-frequency measurement and an inter-RAT mobility measurement during the measurement gap.
10. The terminal of claim 6 , wherein the transmitting module and the receiving module are included in a physical layer module, wherein the at least one HARQ process module is included in a MAC (medium access control) layer module, and
wherein the measurement module comprises at least one of a module in an RRC (radio resource control) layer module and a module in the physical layer module.
11. The terminal of claim 6 , wherein the HARQ operation is a synchronous HARQ operation.