Communication method and user equipment of performing bandwidth part switching between a non-dormant bandwidth part and a dormant bandwidth part

1. A communication method of performing Bandwidth Part (BWP) switching between a non-dormant BWP and a dormant BWP, the communication method performed by a User Equipment (UE) configured by a Base Station (BS) with a serving cell and a dormancy group to which the serving cell belongs, the communication method comprising:

activating the non-dormant BWP as an activated BWP for the serving cell;

initializing a first Random Access (RA) procedure on the serving cell;

receiving, from the BS, one of a first indication for BWP switching for the serving cell and a second indication for BWP switching for the dormancy group while the first RA procedure is ongoing;

switching the activated BWP for the serving cell, based on the one of the first indication and the second indication, from the non-dormant BWP to the dormant BWP;

stopping the first RA procedure after receiving the one of the first indication and the second indication;

initializing a second RA procedure on the serving cell after stopping the first RA procedure; and

not performing transmission on an RA channel on the dormant BWP during the second RA procedure.

2. The communication method of claim 1 , further comprising:

stopping a BWP inactivity timer of the serving cell after receiving the one of the first indication and the second indication.

3. The communication method of claim 1 , further comprising:

performing operations on the dormant BWP, the operations including:

stopping monitoring a Physical Downlink Control Channel (PDCCH) on the serving cell; and

performing Channel State Information (CSI) measurements for the serving cell.

4. The communication method of claim 1 , wherein:

the second indication includes a bit;

the UE is instructed to switch the activated BWP for the serving cell from the non-dormant BWP to the dormant BWP when the bit is set to a first binary value; and

the UE is instructed to switch the activated BWP for the serving cell from the dormant BWP to the non-dormant BWP when the bit is set to a second binary value.

5. The communication method of claim 1 , wherein:

the second indication is received via a Physical Downlink Control Channel (PDCCH); and

the second indication is included in one of Downlink Control Information (DCI) scrambled by a Power Saving Radio Network Temporary Identity (PS-RNTI), DCI with format 0_1, and DCI with format 1_1.

6. The communication method of claim 1 , wherein the first indication is received, via a Physical Downlink Control Channel (PDCCH) or via a Radio Resource Control (RRC) reconfiguration message, for BWP switching for the serving cell.

7. The communication method of claim 1 , wherein the second indication includes a bitmap associated with at least one dormancy group, each bit of the bitmap corresponding to one of the at least one dormancy group.

8. The communication method of claim 1 , wherein the serving cell is a Secondary Cell (SCell).

9. The communication method of claim 1 , wherein the non-dormant BWP and the dormant BWP are Downlink (DL) BWPs.

10. A User Equipment (UE) of performing Bandwidth Part (BWP) switching between a non-dormant BWP and a dormant BWP, the UE configured by a Base Station (BS) with a serving cell and a dormancy group to which the serving cell belongs, the UE comprising:

a processor; and

a memory coupled to the processor, wherein the memory stores at least one computer-executable program that, when executed by the processor, causes the UE to:

activate the non-dormant BWP as an activated BWP for the serving cell;

initialize a first Random Access (RA) procedure on the serving cell;

receive, from the BS, one of a first indication for BWP switching for the serving cell and a second indication for BWP switching for the dormancy group while the first RA procedure is ongoing;

switch the activated BWP for the serving cell, based on the one of the first indication and the second indication, from the non-dormant BWP to the dormant BWP;

stop the first RA procedure after receiving the one of the first indication and the second indication;

initialize a second RA procedure on the serving cell after stopping the first RA procedure; and

not perform transmission on an RA channel on the dormant BWP during the second RA procedure.

11. The UE of claim 10 , wherein when the at least one computer-executable program is executed by the processor, the at least one computer-executable program further causes the UE to:

stop a BWP inactivity timer of the serving cell after receiving the one of the first indication and the second indication.

12. The UE of claim 10 , wherein when the at least one computer-executable program is executed by the processor, the at least one computer-executable program further causes the UE to:

perform operations on the dormant BWP, the operations including:

stopping monitoring a Physical Downlink Control Channel (PDCCH) on the serving cell; and

performing Channel State Information (CSI) measurements for the serving cell.

13. The UE of claim 10 , wherein:

the second indication includes a bit;

the UE is instructed to switch the activated BWP for the serving cell from the non-dormant BWP to the dormant BWP when the bit is set to a first binary value; and

the UE is instructed to switch the activated BWP for the serving cell from the dormant BWP to the non-dormant BWP when the bit is set to a second binary value.

14. The UE of claim 10 , wherein:

the second indication is received via a Physical Downlink Control Channel (PDCCH); and

the second indication is included in one of Downlink Control Information (DCI) scrambled by a Power Saving Radio Network Temporary Identity (PS-RNTI), DCI with format 0_1, and DCI with format 1_1.

15. The UE of claim 10 , wherein the first indication is received, via a Physical Downlink Control Channel (PDCCH) or via a Radio Resource Control (RRC) reconfiguration message, for BWP switching for the serving cell.

16. The UE of claim 10 , wherein the second indication includes a bitmap associated with at least one dormancy group, each bit of the bitmap corresponding to one of the at least one dormancy group.

17. The UE of claim 10 , wherein the serving cell is a Secondary Cell (SCell).

18. The UE of claim 10 , wherein the non-dormant BWP and the dormant BWP are Downlink (DL) BWPs.