Method and user equipment for construction of downlink control information format

1. A method performed by a User Equipment (UE) for construction of a downlink control information (DCI) format, the method comprising:

receiving, from a base station (BS), a radio resource control (RRC) message comprising information for configuring a Hybrid Automatic Repeat reQuest-ACKnowledge (HARQ-ACK) codebook list, first DCI and second DCI;

determining whether a size difference exists between a first downlink assignment index (DAI) field of the first DCI and a second DAI field of the second DCI; and

inserting at least one bit with a zero value into one of the first DAI field and the second DAI field when the size difference between the first DAI field of the first DCI and the second DAI field of the second DCI exists,

wherein the HARQ-ACK codebook list includes a first HARQ-ACK codebook indicated by the first DCI and a second HARQ-ACK codebook indicated by the second DCI, and the first DCI and the second DCI have a same format.

2. The method of claim 1 , wherein the inserted at least one bit with the zero value forms a most significant bit in the one of the first DAI field and the second DAI field.

3. The method of claim 1 , wherein a first priority of the first HARQ-ACK codebook and a second priority of the second HARQ-ACK codebook are different.

4. The method of claim 1 , wherein:

the first HARQ-ACK codebook and the second HARQ-ACK codebook have different types, and

the types refer to a semi-static type and a dynamic type.

5. A User Equipment (UE) in a wireless communication system for construction of a downlink control information (DCI) format, the wireless communication system comprising a Base Station (BS), the UE comprising:

a memory having computer-readable instructions stored therein; and

at least one processor coupled to the memory, the at least one processor being configured to execute the computer-readable instructions to cause the UE to:

receive, from the BS, a radio resource control (RRC) message comprising information for configuring a Hybrid Automatic Repeat reQuest-ACKnowledge (HARQ-ACK) codebook list, first DCI and second DCI;

determine whether a size difference exists between a first downlink assignment index (DAI) field of the first DCI and a second DAI field of the second DCI; and

insert at least one bit with a zero value into one of the first DAI field and the second DAI field when the size difference between the first DAI field of the first DCI and the second DAI field of the second DCI exists,

wherein the HARQ-ACK codebook list includes a first HARQ-ACK codebook indicated by the first DCI and a second HARQ-ACK codebook indicated by the second DCI, and the first DCI and the second DCI have a same format.

6. The UE of claim 5 , wherein the inserted at least one bit with the zero value forms a most significant bit in the one of the first DAI field and the second DAI field.

7. The UE of claim 5 , wherein a first priority of the first HARQ-ACK codebook and a second priority of the second HARQ-ACK codebook are different.

8. The UE of claim 5 , wherein:

the first HARQ-ACK codebook and the second HARQ-ACK codebook have different types, and

the types refer to a semi-static type and a dynamic type.