User equipment, base station apparatus, communication method of a user equipment and communication method of a base station apparatus

1. A User Equipment (UE) for receiving system information, the UE comprising:

a memory; and

at least one processor coupled to the memory, the at least one processor configured to:

receive a first type system information block (SIB) from a base station (BS) apparatus, the first type SIB comprising an identifier of a second type SIB and a first value tag indicating a version of the second type SIB, validity of the first value tag being cell-specific or area-specific;

determine the validity of the first value tag according to a cell upon which the UE is camping or a geographical area in which the UE is located; and

after determining the validity of the first value tag, perform operations including:

comparing the first value tag with a prestored second value tag, the prestored second value tag being associated with a prestored second type SIB;

transmitting to the BS apparatus a request message for the second type SIB when the prestored second value tag does not match the first value tag; and

receiving the second type SIB as a response to the request message from the BS apparatus.

2. The UE of claim 1 , wherein the first type SIB is used for receiving minimum system information comprising information required for an initial access to the BS apparatus.

3. The UE of claim 2 , wherein the second type SIB comprises other system information not included in the minimum system information.

4. The UE of claim 1 , wherein the first type SIB indicates that the second type SIB is provided on-demand.

5. The UE of claim 1 , wherein the request message comprises the prestored second value tag.

6. The UE of claim 1 , wherein the at least one processor is further configured to:

receive compressed content from the BS apparatus, the compressed content comprising a difference between the second type SIB and the prestored second type SIB.

7. The UE of claim 1 , wherein the at least one processor is further configured to:

update the prestored second value tag after receiving the second type SIB.

8. A method performed by a User Equipment (UE) for receiving system information, the method comprising:

receiving a first type system information block (SIB) from a base station (BS) apparatus, the first type SIB comprising an identifier of a second type SIB and a first value tag indicating a version of the second type SIB, validity of the first value tag being cell-specific or area-specific;

determining the validity of the first value tag according to a cell upon which the UE is camping or a geographical area in which the UE is located; and

after determining the validity of the first value tag, performing operations including:

comparing the first value tag with a prestored second value tag, the prestored second value tag being associated with a prestored second type SIB;

transmitting to the BS apparatus a request message for the second type SIB when the prestored second value tag does not match the first value tag; and

receiving the second type SIB as a response to the request message from the BS apparatus.

9. The method of claim 8 , wherein the first type SIB is used for receiving minimum system information comprising information required for an initial access to the BS apparatus.

10. The method of claim 9 , wherein the second type SIB comprises other system information not included in the minimum system information.

11. The method of claim 8 , wherein the first type SIB indicates that the second type SIB is provided on-demand.

12. The method of claim 8 , wherein the request message comprises the prestored second value tag.

13. The method of claim 8 , further comprising:

receiving compressed content from the BS apparatus, the compressed content comprising a difference between the second type SIB and the prestored second type SIB.

14. The method of claim 8 , further comprising:

updating the prestored second value tag after receiving the second type SIB.