Method and user equipment for hybrid automatic repeat request mode operation in non-terrestrial network

A User Equipment (UE) for performing a Hybrid Automatic Repeat Request (HARQ) mode operation in a non-terrestrial network (NTN), the UE comprising:

• at least one non-transitory computer-readable medium storing one or more computer-executable instructions;
• and
• at least one processor coupled to the at least one non-transitory computer-readable medium and configured to execute the one or more computer-executable instructions to cause the UE to:
• receive, from a Base Station (BS), a first configuration and a second configuration for a serving cell, the first configuration including a first bitmap for indicating a HARQ mode of each uplink (UL) HARQ process in a UL HARQ process set, each bit in the first bitmap being associated with a corresponding UL HARQ process in the UL HARQ process set, and the second configuration including a second bitmap for indicating a Downlink (DL) HARQ feedback condition of each DL HARQ process in a DL HARQ process set, each bit in the second bitmap being associated with a corresponding DL HARQ process in the DL HARQ process set;
• identify, based on the first bitmap, whether the HARQ mode of each UL HARQ process in the UL HARQ process set is related to a first HARQ mode, in which a HARQ Round Trip Time (RTT) timer for the UL HARQ process is set and started by the UE, or a second HARQ mode, in which the HARQ RTT timer for the UL HARQ process is not started by the UE;
• identify, based on the second bitmap, whether the DL HARQ feedback condition of each DL HARQ process in the DL HARQ process set is related to a first DL HARQ feedback condition or a second DL HARQ feedback condition;
• receive, from the BS, a Radio Resource Control (RRC) Information Element (IE) including a logical channel configuration for a logical channel, the logical channel configuration including a parameter that indicates at least one of the first HARQ mode and the second HARQ mode is allowed to be mapped to the logical channel;
• receive, from the BS, a UL grant including a HARQ process identifier that indicates a UL HARQ process in the UL HARQ process set;
• perform, based on a Logical Channel Prioritization (LCP) procedure, a transmission for the UL HARQ process via the UL grant;
• and
• determine, based on the parameter and the HARQ mode of the UL HARQ process, whether the logical channel is allowed to be selected for the transmission.