Method and apparatus for terminal to perform buffer status reporting and power headroom reporting in mobile wireless communication system

1 . A method by a terminal, the method comprising:

receiving, by the terminal in a first cell, a small data transmission configuration;

receiving, by the terminal in a second cell, a value for a first timer;

starting, by the terminal in the second cell and based on the small data transmission configuration and the value for the first timer, the first timer at a first specific time point;

performing, by the terminal in the second cell, a first operation set while the first timer is running;

stopping, by the terminal in the second cell, the first timer at a second specific time point; and

performing, by the terminal in the second cell, a second operation set while the first timer is not running;

wherein the first operation set comprises:

transmitting, by the terminal, a buffer status report based on second logical channel group mapping information and a second buffer status report configuration; and

transmitting, by the terminal, a power headroom report based on a second power headroom report configuration,

wherein the second operation set comprises:

transmitting, by the terminal, a buffer status report based on the second logical channel group mapping information and a first buffer status report configuration; and

transmitting, by the terminal, a power headroom report based on a first power headroom report configuration,

wherein the second logical channel group mapping information indicates a mapping between a specific radio bearer and a logical channel group,

wherein each of the first buffer status report configuration and the second buffer status report configuration indicates a timer value for periodic reporting, and

wherein each of the first power headroom report configuration and the second power headroom report configuration indicates a format of power headroom reporting.

2 . The method of claim 1 ,

wherein the first specific time point is:

after a small data transmission procedure starts; and

before Signaling Radio Bearer1 (SRB1) resumes, and

wherein the second specific time point is:

after a first downlink Radio Resource Control (RRC) message is received in the second cell; and

before a cell group configuration contained in the first downlink RRC message is applied.

3 . The method of claim 1 , wherein the first power headroom report configuration and the first buffer status report configuration are indicated to the terminal in the first cell before the first timer starts.

4 . The method of claim 1 , wherein the second logical channel group mapping information is indicated to the terminal in the first cell before the first timer starts.

5 . The method of claim 1 , wherein a point of time when the first buffer status report configuration is available to the terminal and a point of time when the second buffer status report configuration is available to the terminal are different.

6 . The method of claim 1 , wherein a point of time when the first power headroom report configuration is available to the terminal and a point of time when the second power headroom report configuration is available to the terminal are different.

7 . A terminal in a wireless communication system, the terminal comprising:

a transceiver configured to transmit and receive a signal; and

a controller configured to control the transceiver to:

receive, in a first cell, a small data transmission configuration,

receive, in a second cell, a value for a first timer,

start, in the second cell and based on the small data transmission configuration and the value for the first timer, the first timer at a first specific time point,

perform, in the second cell, a first operation set while the first timer is running,

stop, in the second cell, the first timer at a second specific time point, and

perform, in the second cell, a second operation set while the first timer is not running,

wherein the first operation set comprises:

transmitting a buffer status report based on second logical channel group mapping information and a second buffer status report configuration; and

transmitting a power headroom report based on a second power headroom report configuration,

wherein the second operation set comprises:

transmitting a buffer status report based on the second logical channel group mapping information and a first buffer status report configuration; and

transmitting a power headroom report based on a first power headroom report configuration,

wherein the second logical channel group mapping information indicates a mapping between a specific radio bearer and a logical channel group,

wherein each of the first buffer status report configuration and the second buffer status report configuration indicates a timer value for periodic reporting, and

wherein each of the first power headroom report configuration and the second power headroom report configuration indicates a format of power headroom reporting.