System and method for handling of an uplink transmission collision with an ACK/NACK signal
Systems and methods for handling of an uplink transmission collision with an ACK/NACK signal are provided. An ACK/NACK may be configured for a repetition sequence. The ACK/NACK signal transmission on a particular subframe can be refrained due to the collision. The UL transmission can be performed on the subframe.
1. A method in a user equipment (UE) comprising:
receiving, at the UE, first configuration information indicating the UE to perform an acknowledgement/negative acknowledgement (ACK/NACK) repetition;
in response to the first configuration information indicating the ACK/NACK repetition:
determining, by the UE, that a transmission time interval (TTI) bundling is not configured;
responsive to determining that the TTI bundling is not configured, determining, by the UE, that a first scheduled physical uplink shared channel (PUSCH) transmission from the UE collides with a transmission of a first ACK/NACK signal from the UE, the first ACK/NACK signal being part of an ACK/NACK repetition sequence; and
responsive to the determining that the first scheduled PUSCH transmission collides with the transmission of the first ACK/NACK signal:
omitting, by the UE, the transmission of the first ACK/NACK signal;
transmitting the first scheduled PUSCH transmission;
setting a hybrid automatic repeat request (HARQ) feedback for the first scheduled PUSCH transmission to an ACK by an HARQ process in response to delivering an ACK from a physical layer to a higher layer of the UE; and
in response to setting the HARQ feedback to an ACK, refraining from non-adaptive retransmissions for the first scheduled PUSCH transmission.
2. The method of claim 1 , further comprising identifying, by a medium access control (MAC) layer of the UE, a collision between the first scheduled PUSCH transmission and the first ACK/NACK signal.
3. The method of claim 1 , wherein the ACK/NACK signal is transmitted on an uplink in response to a physical downlink shared channel (PDSCH) reception.
4. The method of claim 1 , wherein the ACK/NACK repetition sequence comprises the first ACK/NACK signal repeated 2, 4, or 6 times in consecutive uplink subframes.
5. A user equipment (UE) for operating in a wireless communications network, comprising one or more processors configured to:
receive, at the UE, first configuration information indicating the UE to perform an acknowledgement/negative acknowledgement (ACK/NACK) repetition;
in response to the first configuration information indicating the ACK/NACK repetition:
determining, by the UE, that a transmission time interval (TTI) bundling is not configured;
responsive to determining that the TTI bundling is not configured, determine, by the UE, that a first scheduled physical uplink shared channel (PUSCH) transmission from the UE collides with a transmission of a first ACK/NACK signal from the UE, the first ACK/NACK signal being part of an ACK/NACK repetition sequence; and
responsive to the determining that the first scheduled PUSCH transmission collides with the transmission of the first ACK/NACK signal:
omit, by the UE, the transmission of the first ACK/NACK signal;
transmit the first scheduled PUSCH transmission;
set a hybrid automatic repeat request (HARQ) feedback for the first scheduled PUSCH transmission to an ACK by an HARQ process; and
in response to setting the HARQ feedback to an ACK, refrain from non-adaptive retransmissions for the first scheduled PUSCH transmission.
6. The UE of claim 5 , the one or more processors further configured to identify, by a medium access control (MAC) layer of the UE, a collision between the first scheduled PUSCH transmission and the first ACK/NACK signal.
7. The UE of claim 5 , wherein the ACK/NACK signal is transmitted on an uplink in response to a physical downlink shared channel (PDSCH) reception.
8. The UE of claim 5 , wherein the ACK/NACK repetition sequence comprises the first ACK/NACK signal repeated 2, 4, or 6 times in consecutive uplink subframes.