Method and apparatus for acquiring system information
A method for acquiring system information (SI) performed by a user equipment (UE) in a radio resource control (RRC)_CONNECTED state is provided. The method includes: performing a first set of operations after determining that the UE is not configured with a common search space (CSS) in an active bandwidth part (BWP); and performing a second set of operations after determining that the UE is configured with the CSS in the active BWP. The first set of operations includes: transmitting, to a cell, a first RRC message for requesting a required system information block (SIB) after determining that the required SIB is provided by the cell; and receiving, from the cell, a second RRC message including the required SIB. The second set of operations includes: transmitting, to the cell, a third RRC message for requesting the required SIB after determining that the required SIB is provided by the cell and the required SIB is not broadcast in the cell; and receiving, from the cell, the required SIB in the CSS.
1. A user equipment (UE) comprising:
one or more non-transitory computer-readable media containing computer-executable instructions embodied therein; and
at least one processor coupled to the one or more non-transitory computer-readable media, the at least one processor configured to execute the computer-executable instructions to:
perform a first set of operations while the UE is in a radio resource control (RRC)_CONNECTED state after determining that the UE is not configured with a common search space (CSS) in an active bandwidth part (BWP), the first set of operations comprising:
transmitting, to a cell, a first RRC message for requesting a required system information block (SIB) after determining that the required SIB is provided by the cell; and
receiving, from the cell, a second RRC message including the required SIB; and
perform a second set of operations while the UE is in the RRC_CONNECTED state after determining that the UE is configured with the CSS in the active BWP, the second set of operations comprising:
transmitting, to the cell, a third RRC message for requesting the required SIB after determining that the required SIB is provided by the cell and the required SIB is not broadcast in the cell; and
receiving, from the cell, the required SIB in the CSS.
2. The UE of claim 1 , wherein the at least one processor is further configured to execute the computer-executable instructions to:
receive, from the cell, a system information block type 1 (SIB1);
wherein the SIB1 indicates whether the required SIB is provided by the cell.
3. The UE of claim 2 , wherein the SIB1 further indicates whether the required SIB is broadcast in the cell.
4. The UE of claim 1 , wherein the first set of operations further comprises:
monitoring a configured UE-specific search space in the active BWP for the reception of the second RRC message after transmitting the first RRC message.
5. The UE of claim 1 , wherein the second set of operations further comprises:
monitoring the CSS for a downlink control information (DCI) format with cyclic redundancy check (CRC) scrambled by a system information radio network temporary identifier (SI-RNTI) to derive a resource for the reception of the required SIB after transmitting the third RRC message.
6. The UE of claim 1 , wherein the second set of operations further comprises:
stop monitoring the CSS during an SI time window after receiving the required SIB.
7. The UE of claim 1 , wherein the at least one processor is further configured to execute the computer-executable instructions to:
receive a fourth RRC message that indicates whether the UE is allowed to request SIB on-demand before determining whether the UE is configured with the CSS in the active BWP.
8. The UE of claim 1 , wherein the at least one processor is further configured to execute the computer-executable instructions to:
start a timer after transmitting the first RRC message;
start the timer after transmitting the third RRC message;
stop the timer after receiving the required SIB; and
receive a fourth RRC message that indicates an initial value of the timer;
wherein the UE is not allowed to transmit a fifth RRC message for requesting another SIB when the timer is running.
9. The UE of claim 1 , wherein the first RRC message indicates at least one of a list of requested SIBs with ENUMERATED format and a list of requested positioning SIBs (posSIBs) with ENUMERATED format.
10. The UE of claim 1 , wherein the at least one processor is further configured to execute the computer-executable instructions to:
send, by a radio link control (RLC) acknowledged mode (AM) entity of the UE, an RLC AM protocol data unit (PDU) that includes the first RRC message to a medium access control (MAC) entity of the UE in an uplink dedicated control channel (UL-DCCH) over signaling radio bearer 1 (SRB1).
11. A method for acquiring system information (SI) performed by a user equipment (UE) in a radio resource control (RRC)_CONNECTED state, the method comprising:
performing a first set of operations after determining that the UE is not configured with a common search space (CSS) in an active bandwidth part (BWP), the first set of operations comprising:
transmitting, to a cell, a first RRC message for requesting a required system information block (SIB) after determining that the required SIB is provided by the cell; and
receiving, from the cell, a second RRC message including the required SIB; and
performing a second set of operations after determining that the UE is configured with the CSS in the active BWP, the second set of operations comprising:
transmitting, to the cell, a third RRC message for requesting the required SIB after determining that the required SIB is provided by the cell and the required SIB is not broadcast in the cell; and
receiving, from the cell, the required SIB in the CSS.
12. The method of claim 11 , further comprising:
receiving, from the cell, a system information block type 1 (SIB1);
wherein the SIB1 indicates whether the required SIB is provided by the cell.
13. The method of claim 12 , wherein the SIB1 further indicates whether the required SIB is broadcast in the cell.
14. The method of claim 11 , wherein the first set of operations further comprises:
monitoring a configured UE-specific search space in the active BWP for the reception of the second RRC message after transmitting the first RRC message.
15. The method of claim 11 , wherein the second set of operations further comprises:
monitoring the CSS for a downlink control information (DCI) format with cyclic redundancy check (CRC) scrambled by a system information radio network temporary identifier (SI-RNTI) to derive a resource for the reception of the required SIB after transmitting the third RRC message.
16. The method of claim 11 , wherein the second set of operations further comprises:
stop monitoring the CSS during an SI time window after receiving the required SIB.
17. The method of claim 11 , further comprising:
receiving a fourth RRC message that indicates whether the UE is allowed to request SIB on-demand before determining whether the UE is configured with the CSS in the active BWP.
18. The method of claim 11 , further comprising:
starting a timer after transmitting the first RRC message;
starting the timer after transmitting the third RRC message;
stopping the timer after receiving the required SIB; and
receiving a fourth RRC message that indicates an initial value of the timer;
wherein the UE is not allowed to transmit a fifth RRC message for requesting another SIB when the timer is running.
19. The method of claim 11 , wherein the first RRC message indicates at least one of a list of requested SIBs with ENUMERATED format and a list of requested positioning SIBs (posSIBs) with ENUMERATED format.
20. The method of claim 11 , further comprising:
sending, by a radio link control (RLC) acknowledged mode (AM) entity of the UE, an RLC AM protocol data unit (PDU) that includes the first RRC message to a medium access control (MAC) entity of the UE in an uplink dedicated control channel (UL-DCCH) over signaling radio bearer 1 (SRB1).