Method and apparatus for controlling uplink power in wireless communication system

1. A method of a user equipment (UE) in a wireless communication system, the method comprising:

establishing a first link with a first base station (BS) and a second link with a second B S;

detecting a power headroom report (PHR) trigger event associated with the first BS; and

in response to the detection of the PHR trigger event, transmitting a dual connectivity PHR of the UE to the first BS through an uplink resource allocated by the first BS and the dual connectivity PHR of the UE to the second BS through an uplink resource allocated by the second BS.

2. The method of claim 1 , wherein the detecting of the PHR trigger event comprises detecting the PHR trigger event based on at least one of a path loss change, a P-Maximum Power Reduction (MPR) change, Scell Activation, Scell Addition, and a power back off change.

3. The method of claim 1 , further comprising:

determining a transmission power of the UE for each of the first BS and the second BS; and

in response to the detection of the PHR trigger event, adjusting a transmission power for each of the first BS and the second BS to determine a power headroom of the UE for at least one of the first BS and the second BS.

4. The method of claim 3 , wherein the determining of the transmission power of the UE comprises:

receiving maximum transmission power distribution information of the UE for the first BS and the second BS from at least one of the first BS and the second BS.

5. The method of claim 1 , further comprising:

detecting another PHR trigger event associated with the BS; and

in response to the detection of the other PHR event, transmitting another dual connectivity PHR to the BS.

6. The method of claim 5 , wherein the detecting of the other PHR trigger event comprises:

detecting the other PHR trigger event based on at least one of a periodic PHR timer, a prohibit PHR timer, reconfiguration, and an uplink buffer data amount associated with at least one of the first BS and the second BS.

7. A method for operating a base station (BS) in a wireless communication system, the method comprising:

receiving, from a user equipment (UE) having a dual connectivity with the BS and another BS, a dual connectivity power headroom report (PHR) of the UE through an uplink resource allocated by the BS,

wherein the dual connectivity PHR is received in response to a detection of a PHR trigger event associated with the other BS, and

wherein the dual connectivity PHR is transmitted from the UE to the other BS through an uplink resource allocated by the other BS.

8. The method of claim 7 , further comprising:

determining a transmission power of the UE for each of the BS and the other BS; and

transmitting, to the UE, information on the transmission power for each of the BS and the other BS.

9. The method of claim 8 , wherein the transmission power is determined for each of the BS and the other BS based on at least one of an aggregated maximum bit rate (AMBR), a path loss, a channel state, a bandwidth, rarity of a resource, the number of connected UEs, and weight factor.

10. The method of claim 7 , further comprising:

in response to the reception of the dual connectivity PHR, adjusting a transmission power of the UE for each of the BS and the other BS; and

transmitting, to the UE, information on the adjusted transmission power,

wherein the transmission power is adjusted based on a data amount of an uplink buffer and channel state information.

11. An apparatus of a user equipment (UE) in a wireless communication system, the apparatus comprising:

one or more processors configured to:

establish a first link with a first base station (BS) and a second link with a second BS, and

detect a power headroom report (PHR) trigger event associated with the first BS; and

a transceiver configured to

transmit a dual connectivity PHR of the UE to the first BS through an uplink resource allocated by the first BS and the dual connectivity PHR of the UE to the second BS through an uplink resource allocated by the second BS, in response to the detection of the PHR trigger event.

12. The apparatus of claim 11 , wherein the one or more processors are further configured to detect the PHR trigger event based on at least one of a path loss change, P-Maximum Power Reduction (MPR) change, Scell Activation, Scell Addition, and a power back off change.

13. The apparatus of claim 11 ,

wherein the one or more processors are further configured to:

determine a transmission power of the UE for each of the first BS and the second BS, and

in response to the detection of the PHR trigger event, adjust transmission power for each of the first BS and the second BS to determine a power headroom of the UE for at least one of the first BS and the second BS.

14. The apparatus of claim 13 , wherein the one or more processors are further configured to receive information on the transmission power for each of the first BS and the second BS from at least one of the first BS and the second BS via the transceiver.

15. The apparatus of claim 11 , wherein the one or more processors are further configured to:

detect another PHR trigger event associated with the first BS, and

transmit the dual connectivity PHR to the first BS.

16. The apparatus of claim 15 , wherein the one or more processors are further configured to detect the other PHR trigger event based on at least one of a periodic PHR timer, a prohibit PHR timer, reconfiguration, and an uplink buffer data amount associated with least one of the first BS and the second BS.

17. An apparatus for a base station (BS) in a wireless communication system, the apparatus comprising:

a transceiver configured to receive, from a user equipment (UE) having a dual connectivity with the BS and another BS, a dual connectivity power headroom report (PHR) of the UE through an uplink resource allocated by the BS,

wherein the dual connectivity PHR is received in response to a detection of a PHR trigger event associated with the other BS, and

wherein the dual connectivity PHR is transmitted from the UE to the other BS through an uplink resource allocated by the other BS.

18. The apparatus of claim 17 , further comprising one or more processors configured to:

determine a transmission power of the UE for each of the BS and the other BS, and

transmit, to the UE, information on a transmission power for each of the BS and the other BS.

19. The apparatus of claim 18 , wherein the transmission power is determined for each of the BS and the other BS based on at least one of an aggregated maximum bit rate (AMBR), a path loss, a channel state, a bandwidth, rarity of a resource, the number of connected UEs, and weight factor.

20. The apparatus of claim 17 , further comprising one or more processors configured to:

adjust a transmission power of the UE for each of the BS and the other BS, and

transmit, to the UE, information on the adjusted transmission power in response to the reception of the dual connectivity PHR,

wherein the transmission power is adjusted based on a data amount of an uplink buffer and channel state information.