On-demand request for system information

1 . A method for requesting system information, comprising:

receiving notification information from a network node, wherein transmission of at least one system information block group is predefined or derived based at least partly on the notification information;

transmitting a request for the at least one system information block group, each of which comprises one or more system information blocks, from a user terminal to the network node, wherein the one or more system information blocks are grouped according to a feature of the one or more system information blocks, wherein the transmitting of the request comprises transmitting a preamble for indicating the at least one system information block group, and wherein the at least one system information block group is indicated by transmission timing of the preamble; and

receiving one or more system information block groups from the network node, wherein the one or more system information block groups comprise the at least one system information block group.

2 . The method according to claim 1 , wherein the transmission of the request comprises transmitting the request to the network node in accordance with a selected transmission timing associated with the at least one system information block group.

3 . The method according to claim 1 , wherein the notification information is included in minimum system information.

4 . The method according to claim 1 , wherein the notification information indicates a correspondence between all of preambles and system information block groups.

5 . The method according to claim 1 , wherein the feature of the one or more system information blocks comprises at least one of functionality and periodicity of the one or more system information blocks.

6 . The method according to claim 1 , further comprising:

receiving an indicator from the network node, wherein the indicator indicates one or both of: which system information block group is being transmitted from the network node, and which system information block group is scheduled to be transmitted from the network node.

7 . The method according to claim 1 , wherein the one or more system information block groups further comprise at least another system information block group which is not requested by the user terminal.

8 . An apparatus for requesting system information, comprising:

at least one processor; and

at least one memory comprising computer program code which, when executed by the at least one processor, cause the apparatus to:

receive notification information from a network node, wherein transmission of at least one system information block group is predefined or derived based at least partly on the notification information;

transmit a request for the at least one system information block group, each of which comprises one or more system information blocks, from a user terminal to the network node, wherein the one or more system information blocks are grouped according to a feature of the one or more system information blocks, wherein to transmit the request comprises transmit of a preamble for indicating the at least one system information block group, and wherein the at least one system information block group is indicated by transmission timing of the preamble; and

receive one or more system information block groups from the network node, wherein the one or more system information block groups comprise the at least one system information block group.

9 . The apparatus according to claim 8 , wherein to transmit the request comprises transmit of the request to the network node in accordance with a selected transmission timing associated with the at least one system information block group.

10 . A method for transmission of system information, comprising:

transmitting notification information to a user terminal, wherein transmission of at least one system information block group is predefined or derived based at least partly on the notification information;

receiving a request for the at least one system information block group, each of which comprises one or more system information blocks, from the user terminal to a network node, wherein the one or more system information blocks are grouped according to a feature of the one or more system information blocks, wherein the receiving of the request comprises receiving a preamble for indicating the at least one system information block group, and wherein the at least one system information block group is indicated by transmission timing of the preamble; and

transmitting one or more system information block groups from the network node, wherein the one or more system information block groups comprise the at least one system information block group.

11 . The method according to claim 10 , wherein the receiving the request comprises receiving the request from the user terminal in accordance with a selected transmission timing associated with the at least one system information block group.

12 . The method according to claim 11 , wherein the notification information is included in minimum system information.

13 . The method according to claim 11 , wherein the notification information indicates a correspondence between all of preambles and system information block groups.

14 . The method according to claim 10 , wherein the feature of the one or more system information blocks comprises at least one of functionality and periodicity of the one or more system information blocks.

15 . The method according to claim 10 , further comprising:

transmitting an indicator to the user terminal, wherein the indicator indicates one or both of: which system information block group is being transmitted from the network node, and which system information block group is scheduled to be transmitted from the network node.

16 . The method according to claim 10 , wherein the one or more system information block groups further comprise at least another system information block group which is not requested by the user terminal.

17 . An apparatus for transmission of system information, comprising:

at least one processor; and

at least one memory comprising computer program code which, when executed by the at least one processor, cause the apparatus to:

transmit notification information to a user terminal, wherein transmission of at least one system information block group is predefined or derived based at least partly on the notification information;

receive a request for the at least one system information block group, each of which comprises one or more system information blocks, from the user terminal to a network node, wherein the one or more system information blocks are grouped according to a feature of the one or more system information blocks, wherein to receive the request comprises reception of a preamble for indicating the at least one system information block group, and wherein the at least one system information block group is indicated by transmission timing of the preamble; and

transmit one or more system information block groups from the network node, wherein the one or more system information block groups comprise the at least one system information block group.

18 . The apparatus according to claim 17 , wherein to receive the request comprises reception of the request from the user terminal in accordance with a selected transmission timing associated with the at least one system information block group.