Wireless communication system and method for mapping of control messages on the un-interface
An LTE mobile communication system in which relays RN ( 14 ), each in communication with a donor eNB ( 13 ) are used to improve the coverage of high data rates, the cell-edge throughput and/or to increase system throughput. The problem addressed is that in the RN←→DeNB ( 13 ) Un interface, all the S1-AP and/or X2-AP messages with different QoS requirements (for example different S1-AP/X2-AP messages that have different time criticalities) have to be delivered in a limited number of Data or Signalling Radio Bearers. A multiplexing mechanism enables the categorization of different types of S1-AP and/or X2-AP messages and the mapping of these to a limited number of Radio Bearers over the Un radio interface.
1. A wireless communication system in which:
subscriber stations ( 12 ) are arranged for wireless communication with a relay station ( 14 ) acting as a base station for those subscriber stations, wherein:
the relay station ( 14 ) is arranged for wireless communication with a donor base station ( 13 ) via a first interface ( 18 );
the donor base station ( 13 ) is arranged for wired and/or wireless communication with peer nodes ( 11 ) and/or other nodes ( 21 , 22 ) of the system, via at least one second interface ( 15 , 16 ); and
said first interface ( 18 ) provides radio bearers ( 51 , 310 ) for sending user data and control messages between the donor base station ( 13 ) and the relay station ( 14 ); and
the or each second interface ( 15 , 16 ) has at least one protocol for sending control messages with differing priorities; wherein
the donor base station ( 13 ) and the relay station ( 14 ) each comprise a mechanism ( 60 ) to combine a plurality of said control messages into one of said radio bearers ( 51 , 310 ) by taking account of their respective priorities, for sending via said first interface ( 18 ); and
the donor base station ( 13 ) and the relay station ( 14 ) are arranged to perform a setup procedure for configuring said first interface ( 18 ), the setup procedure including exchanging information about said priorities.
2. The system according to claim 1 wherein said mechanism ( 60 ) is arranged to determine the priority of a control message from one or more of:
a QoS requirement of the control message;
the protocol used to send the control message via the second interface ( 15 , 16 );
whether the control message originates from a peer node ( 11 ) or another node ( 22 );
whether the control message relates to a plurality of subscriber stations ( 12 ) or to an individual subscriber station; and
whether the control message relates to an emergency.
3. The system according to claim 2 further comprising at least one organization and management node for communicating organization and management messages and wherein said mechanism ( 60 ) is arranged to further to determine the priorities based on whether the control message is an Operations, Administration, Maintenance message.
4. The system according to claim 1 wherein the donor base station ( 13 ) further comprises a bearer setup mechanism for constructing said radio bearer ( 51 , 310 ) and informing the relay station ( 14 ) of related context information.
5. The system according to claim 1 wherein the control messages sent via the or each second interface ( 15 , 16 ) use a secure transmission protocol in which each message is assigned to a stream using a secure transmission protocol association, and said mechanism is arranged to combine the streams into a number of radio bearers ( 51 , 310 ) which is less than the number of streams.
6. The system according to claim 5 wherein the relay station ( 14 ) is arranged to update the donor base station ( 13 ) upon a change in the secure transmission protocol association.
7. The system according to claim 5 wherein said mechanism ( 60 ) includes a multiplexer/demultiplexer for multiplexing control messages into radio bearers ( 51 , 310 ) for transmission via said first interface ( 18 ) and for demultiplexing control messages received via said first interface ( 18 ).
8. The system according to claim 7 wherein the multiplexer/demultiplexer employs fixed length partitioning of the streams.
9. The system according to claim 7 wherein the multiplexer/demultiplexer employs a predefined pattern of spaces for streams.
10. The system according to claim 5 wherein said mechanism ( 60 ) is arranged to form, from packets in respective said streams, a new packet structured to reflect the relative priorities of the streams.
11. The system according to claim 10 wherein said mechanism ( 60 ) employs a distinctive packet header to identify the new packet.
12. A donor base station ( 13 ) adapted for use in the system according to claim 1 .
13. A relay station ( 14 ) adapted for use in the system according to claim 1 .
14. A wireless communication method comprising:
subscriber stations ( 12 ) wirelessly communicating with a relay station ( 14 ) acting as a base station for those subscriber stations;
the relay station ( 14 ) wirelessly communicating with a donor base station ( 13 ) via a first interface ( 18 );
the donor base station ( 13 ) communicating with peer nodes ( 11 ) and/or higher level nodes ( 21 , 22 ) of the system, via at least one second interface ( 15 , 16 );
sending user data and control messages between the donor base station ( 13 ) and the relay station ( 14 ) by using radio bearers defined in said first interface ( 18 ); and
via the or each second interface ( 15 , 16 ) sending control messages with differing priorities in accordance with at least one protocol; wherein
the donor base station ( 13 ) and the relay station ( 14 ) perform a setup procedure for configuring said first interface ( 18 ), the setup procedure including exchanging information about priorities of the control messages; and the donor base station ( 13 ) or the relay station ( 14 ) combine a plurality of said control messages into one of said radio bearers ( 51 , 310 ) by taking account of their respective priorities, for sending via said first interface ( 18 ).