METHOD AND APPARATUS FOR SUPPORTING COMMUNICATION VIA A RELAY NODE

1 . A method for supporting communication via a relay node, the method comprising:

a relay node receiving WTRU buffer status reports (BSRs) from a plurality of wireless transmit/receive unit (WTRUs) that are served by the relay node, wherein the WTRU BSRs indicate uplink buffer status at the WTRUs; and

the relay node sending the WTRU BSRs to a donor evolved Node B (DeNB).

2 . The method of claim 1 further comprising:

the relay node sending a relay node BSR to the DeNB, the relay node BSR indicating a relay node uplink buffer status and/or a relay node downlink buffer status at the relay node.

3 . The method of claim 2 wherein the relay node uplink buffer status is generated based on a sum of uplink buffer accumulations for active WTRU radio bearers (RBs) of one or more WTRUs, or active WTRU RBs belonging to one or more reporting groups, and the relay node downlink buffer status is generated based on a sum of downlink buffer accumulations for active WTRU RBs of one or more WTRUs, or active WTRU RBs belonging to one or more reporting groups.

4 . The method of claim 3 wherein the reporting groups are organized per-WTRU or per-quality of service (QoS) associated with a WTRU DRB.

5 . The method of claim 2 wherein the relay node BSR is triggered either periodically, based on occurrence of a configured triggering event, or based on combination of a periodic timer and occurrence of a configured triggering event.

6 . The method of claim 1 wherein the WTRU BSRs are reported to the DeNB individually or some WTRU BSRs are aggregated on a group-basis.

7 . The method of claim 1 further comprising:

sending a satisfaction indicator indicating whether the relay node is satisfied or not with its resource allocation.

8 . A method for supporting communication via a relay node, the method comprising:

the relay node sending a radio resource control (RRC) message to a donor eNode B (DeNB) for requesting radio resource configuration or reconfiguration on a condition that a handover request acknowledge message is received from the DeNB in response to a request for handover for a wireless transmit/receive unit (WTRU) from the relay node to a handover target, data forwarding to the DeNB is completed for the WTRU, an end marker is received, or a WTRU context release message is received.

9 . The method of claim 8 further comprising:

the relay node sending an RRC message to the DeNB to indicate a need for configuration or reconfiguration on a condition that a WTRU application changes quality of service requirements, adjustment on a WTRU-relay node interface affects a relay node-DeNB interface configuration, the relay node transitions from a connected state to an idle state, some of system information parameter values change, a total WTRU uplink buffer exceeds a threshold, a total relay node downlink buffer exceeds a threshold, and/or when a WTRU-relay node interface needs to be reconfigured.

10 . A relay node comprising:

a transceiver; and

a processor configured to receive WTRU buffer status reports (BSRs) from a plurality of wireless transmit/receive unit (WTRUs) that are served by the relay node, and send the WTRU BSRs to a donor evolved Node B (DeNB), wherein the WTRU BSRs indicate uplink buffer status at the WTRUs.

11 . The relay node of claim 10 wherein the processor is configured to generate, and send, a relay node BSR to the DeNB, the relay node BSR indicating a relay node uplink buffer status and/or a relay node downlink buffer status at the relay node.

12 . The relay node of claim 11 wherein the processor is configured to generate the relay node uplink buffer status based on a sum of uplink buffer accumulations for active WTRU radio bearers (RBs) of one or more WTRUs, or active WTRU RBs belonging to one or more reporting groups, and generate the relay node downlink buffer status based on a sum of downlink buffer accumulations for active WTRU RBs of one or more WTRUs, or active WTRU RBs belonging to one or more reporting groups.

13 . The relay node of claim 12 wherein the reporting groups are organized per-WTRU or per-quality of service (QoS) associated with a WTRU DRB.

14 . The relay node of claim 11 wherein the relay node BSR is triggered either periodically, based on occurrence of a configured triggering event, or based on combination of a periodic timer and occurrence of a configured triggering event.

15 . The relay node of claim 10 wherein the WTRU BSRs are reported to the DeNB individually or some WTRU BSRs are aggregated on a group-basis.

16 . The relay node of claim 10 wherein the processor is configured to send a satisfaction indicator indicating whether the relay node is satisfied or not with its resource allocation.

17 . A relay node comprising:

a transceiver; and

a processor configured to send a radio resource control (RRC) message to a donor eNodeB (DeNB) for requesting radio resource configuration or reconfiguration on a condition that a handover request acknowledge message is received from the DeNB in response to a request for handover for a wireless transmit/receive unit (WTRU) from the relay node to a handover target, data forwarding to the DeNB is completed for the WTRU, an end marker is received, or a WTRU context release message is received.

18 . The relay node of claim 17 wherein the processor is configured to send an RRC message to the DeNB to indicate a need for configuration or reconfiguration on a condition that a WTRU application changes quality of service requirements, adjustment on a WTRU-relay node interface affects a relay node-DeNB interface configuration, the relay node transitions from a connected state to an idle state, some of system information parameter values change, a total WTRU uplink buffer exceeds a threshold, a total relay node downlink buffer exceeds a threshold, and/or when a WTRU-relay node interface needs to be reconfigured.