RANDOM ACCESS PROCEDURE(S) FOR RADIO SYSTEM

1 . A user equipment comprising:

receiver circuitry configured to receive from a base station apparatus configuration parameters for a random access procedure, wherein the configuration parameters include a set of random access preambles and physical random access channel (PRACH) resources reserved for a request of system information;

processor circuitry configured to select a random access preamble and PRACH resource from the set of random access preambles and the PRACH resources in a case of requesting the system information; and

transmitter circuitry configured to transmit the random access preamble using the PRACH resource.

2 . The user equipment of claim 1 , wherein the request of system information requests from the base station apparatus an on-demand delivery of a system information block (SIB) or a group of SIBs.

3 . The user equipment of claim 2 , wherein the configuration parameters comprise a list of information elements, each information element comprising identification(s) of the SIBs or the group of SIBs.

4 . The user equipment of claim 3 , wherein the information element further comprises one or more random access preambles, one of which is selected for the request of the SIB or the group of SIBs indicated in the information element.

5 . The user equipment of claim 3 , wherein the information element further comprises one or more PRACH resources, one of which is selected for the request of the SIB or the group of SIBs indicated in the information element.

6 . A base station apparatus comprising:

receiver circuitry and transmitter circuitry configured to communicate across a radio interface with a user equipment;

processor circuitry configured to:

broadcast configuration parameters for a random access procedure, wherein the configuration parameters include a set of random access preambles and physical random access channel (PRACH) resources reserved for a request of system information;

receive a preamble sequence associated with one of the random access preambles on one of the PRACH resources;

identify and process a request of system information from the user equipment.

7 . The base station apparatus of claim 6 , wherein the request of system information requests from the base station apparatus an on-demand delivery of a system information block (SIB) or a group of SIBs.

8 . The base station apparatus of claim 7 , wherein the configuration parameters comprise a list of information elements, each information element comprising identification(s) of the SIBs or the group of SIBs.

9 . The base station apparatus of claim 8 , wherein the information element further comprises one or more random access preambles, one of which is selected for the request of the SIB or the group of SIBs indicated in the information element.

10 . The base station apparatus of claim 8 , wherein the information element further comprises one or more PRACH resources, one of which is selected for the request of the SIB or the group of SIBs indicated in the information element.

11 . A method for a user equipment comprising:

receiving, from a base station apparatus, configuration parameters for a random access procedure, wherein the configuration parameters include a set of random access preambles and PRACH resources reserved for a request of system information,

selecting a random access preamble and physical random access channel (PRACH) resource from the set of random access preambles and the PRACH resources in a case of requesting the system information; and

transmitting the random access preamble using the PRACH resource.

12 . The method of claim 11 , wherein the request of system information requests from the base station apparatus an on-demand delivery of a system information block (SIB) or a group of SIBs.

13 . The method of claim 12 , wherein the configuration parameters comprise a list of information elements, each information element comprising identification(s) of the SIBs or the group of SIBs.

14 . The method of claim 13 , wherein the information element further comprises one or more random access preamble indices, one of which is selected for the request of the SIB or the group of SIBs indicated in the information element.

15 . The method of claim 13 , wherein the information element further comprises one or more PRACH resources, one of which is selected for the request of the SIB or the group of SIBs indicated in the information element.

16 . A method for a base station apparatus comprising:

using receiver circuitry and transmitter circuitry to communicate across a radio interface with a user equipment;

using processor circuitry to:

broadcast configuration parameters for a random access procedure, wherein the configuration parameters include a set of random access preambles and physical random access channel (PRACH) resources reserved for a request of system information;

receive a preamble sequence associated with one of the random access preambles on one of the PRACH resources;

identify and process a request of system information from the user equipment.

17 . The method of claim 16 , wherein the request of system information requests from the base station apparatus an on-demand delivery of a system information block (SIB) or a group of SIBs.

18 . The method of claim 17 , wherein the configuration parameters comprise a list of information elements, each information element comprising identification(s) of the SIBs or the group of SIBs.

19 . The method of claim 18 , wherein the information element further comprises one or more random access preambles, one of which is selected for the request of the SIB or the group of SIBs indicated in the information element.

20 . The method of claim 18 , wherein the information element further comprises one or more PRACH resources, one of which is selected for the request of the SIB or the group of SIBs indicated in the information element.