On-demand system information request procedure and error handling
A method of wireless communications performed by a user equipment (UE) is provided. The method includes performing an on-demand system information (SI) request procedure in a cell; and performing an error handling procedure if the on-demand SI request procedure in the cell is unsuccessful. The error handling procedure includes storing SI request failure information.
1. A method of an on-demand system information (SI) request procedure performed by a user equipment (UE), the method comprising:
transmitting a first SI request message to a base station (BS) after determining that the UE is in a connected state, the first SI request message including at least one requested system information block (SIB);
activating a prohibit timer; and
transmitting a second SI request message to the BS only when the at least one requested SIB is not received and the prohibit timer expires.
2. The method of claim 1 , wherein the on-demand SI request procedure is unsuccessful when one of the following conditions is met:
a number of times the UE transmits a random access preamble reaches a threshold; and
the UE receives SI request rejection information.
3. The method of claim 1 , wherein when the UE is in a dual connectivity mode, the method further comprises:
transmitting a third SI request message to a master node when the UE requires on-demand system information of a cell belonging to a secondary node.
4. The method of claim 1 , wherein the first SI request message is transmitted on signaling radio bearer 1 (SRB1).
5. The method of claim 1 , further comprising:
receiving, from the BS, the at least one requested SIB via dedicated signaling that is transmitted in response to the first SI request message.
6. The method of claim 1 , further comprising:
transmitting a fourth SI request message to the BS after determining that the UE is not in the connected state, the fourth SI request message including at least one requested SI message.
7. The method of claim 6 , wherein the fourth SI request message is transmitted on signaling radio bearer 0 (SRB0).
8. The method of claim 1 , further comprising:
storing SI request failure information after determining that the on-demand SI request procedure is unsuccessful.
9. The method of claim 8 , wherein the SI request failure information comprises at least one of the following:
the at least one requested SIB;
the at least one requested SI message;
a cell identifier (ID) associated with the BS;
a synchronization signal block (SSB) index for performing the on-demand SI request procedure;
a message type of the on-demand SI request procedure; and
a timestamp for performing the on-demand SI request procedure.
10. The method of claim 8 , further comprising:
transmitting the SI request failure information;
wherein the SI request failure information is transmitted to a master node when the UE is in a dual connectivity mode.
11. A user equipment (UE), comprising:
one or more non-transitory computer-readable media having computer-executable instructions embodied thereon; and
at least one processor coupled to the one or more non-transitory computer-readable media, and configured to execute the computer-executable instructions to perform operations for an on-demand system information (SI) request procedure, the operations comprising:
transmitting a first SI request message to a base station (BS) after determining that the UE is in a connected state, the first SI request message including at least one requested system information block (SIB);
activating a prohibit timer; and
transmitting a second SI request message to the BS only when the at least one requested SIB is not received and the prohibit timer expires.
12. The UE of claim 11 , wherein the on-demand SI request procedure is unsuccessful when one of the following conditions is met:
a number of times the UE transmits a random access preamble reaches a threshold; and
the UE receives SI request rejection information.
13. The UE of claim 11 , wherein when the UE is in a dual connectivity mode, the operations further comprise:
transmitting a third SI request message to a master node when the UE requires on-demand system information of a cell belonging to a secondary node.
14. The UE of claim 11 , wherein the first SI request message is transmitted on signaling radio bearer 1 (SRB1).
15. The UE of claim 11 , wherein the operations further comprise:
receiving, from the BS, the at least one requested SIB via dedicated signaling that is transmitted in response to the first SI request message.
16. The UE of claim 11 , wherein the operations further comprise:
transmitting a fourth SI request message to the BS after determining that the UE is not in the connected state, the fourth SI request message including at least one requested SI message.
17. The UE of claim 16 , wherein the fourth SI request message is transmitted on signaling radio bearer 0 (SRB0).
18. The UE of claim 11 , wherein the operations further comprise:
storing SI request failure information after determining that the on-demand SI request procedure is unsuccessful.
19. The UE of claim 18 , wherein the SI request failure information comprises at least one of the following:
the at least one requested SIB;
the at least one requested SI message;
a cell identifier (ID) associated with the BS;
a synchronization signal block (SSB) index for performing the on-demand SI request procedure;
a message type of the on-demand SI request procedure; and
a timestamp for performing the on-demand SI request procedure.
20. The UE of claim 18 , wherein the operations further comprise:
transmitting the SI request failure information;
wherein the SI request failure information is transmitted to a master node when the UE is in a dual connectivity mode.