Handling service data application protocol (SDApP) end markers at handover
Methods performed by base stations and wireless devices in networks are disclosed. A method performed by a base station comprises: initiating a QoS-flow to DRB remapping; informing a target base station that the remapping is ongoing; and providing the target base station an old and a new QoS-flow to DRB mapping, wherein the old mapping was in place before the remapping, and the new mapping will be in place after the remapping. Another method performed by a base station comprises: receiving an indication from a further base station that QoS-flow to DRB remapping is ongoing; receiving an old and a new QoS-flow to DRB mapping from the further base station; and receiving signals from a wireless device using the old and new QoS-flow to DRB mappings. A method performed by the wireless device comprises: sending data packets using a first QoS-flow to DRB mapping; receiving a new mapping; and sending an SOAR end marker, indicating that the wireless device is applying the new mapping. Also disclosed are base stations and wireless devices configured to perform the methods.
1. A method performed by a source base station, the method comprising:
initiating a Quality of Service-flow (QoS-flow) to Data Resource Bearer (DRB) remapping;
providing a target base station with one or more new QoS-flow to DRB mappings; and
sending the target base station a Sequence Number (SN) status transfer message, the SN status transfer message comprising a list of DRBs subject to status transfer, the list of DRBs subject to the status transfer indicating one or more old QoS-flow to DRB mappings,
wherein the list of DRBs subject to the status transfer includes a QoS flow mapping list that indicates one or more uplink (UL) QoS flows for which the source base station has initiated the QoS flow to DRB remapping and a Service Data Adaptation Protocol (SDAP) end marker has not been received at the source base station.
2. The method of claim 1 , wherein the QoS-flow to DRB remapping is ongoing when a handover from the source base station to the target base station is triggered.
3. The method of claim 1 , wherein the list of DRBs subject to the status transfer comprises a DRB Identity (DRB ID) and at least one of an Uplink (UL) count value and a Downlink (DL) count value.
4. The method of claim 1 , wherein:
the list of DRBs subject to the status transfer comprises a DRB Identity (DRB ID) and an Uplink (UL) count value associated with the DRB ID; and
with respect to a DRB identified by the DRB ID, the target base station does not deliver any uplink packet having a Packet Data Convergence Protocol Sequence Number (PDCP-SN) lower than a value contained within the UL count value associated with the DRB ID.
5. The method of claim 1 wherein, when the source base station has accepted a request for uplink forwarding from the target base station in relation to a DRB, the SN status transfer message comprises a list of missing and received uplink Service Data Units (SDUs) for that DRB.
6. The method of claim 1 , wherein the source base station is a node from which DRB context is transferred, and wherein the target base station is a node to which the DRB context is transferred in dual connectivity.
7. The method of claim 6 , wherein the method is performed when the QoS-flow to DRB remapping is ongoing when the DRB context transfer is triggered.
8. The method of claim 1 , wherein the one or more old QoS-flow to DRB mappings and the one or more new QoS-flow to DRB mappings enable the target base station to receive Service Data Adaptation Protocol (SDAP) headers from a wireless device.
9. The method of claim 1 , wherein:
the list of DRBs subject to the status transfer comprises a DRB Identity (DRB ID) and a Downlink (DL) count value associated with the DRB ID; and
with respect to a DRB identified by the DRB ID, the target base station node uses a value of a Packet Data Convergence Protocol Sequence Number (PDCP-SN) from the DL count value for the first downlink packet for which no PDCP-SN has previously been assigned.
10. The method of claim 1 , wherein the source base station is a source Next Generation Radio Access Network (NG-RAN) node and the target base station is a target NG-RAN node for handover.
11. A source base station comprising:
processing circuitry configured to perform the steps of:
i. initiating a Quality of Service-flow (QoS-flow) to Data Radio Bearer (DRB) remapping;
ii. providing a target base station with one or more new QoS-flow to DRB mappings; and
iii. sending the target base station a Sequence Number (SN) status transfer message, the SN status transfer message comprising a list of DRBs subject to status transfer, the list of DRBs subject to the status transfer indicating one or more old QoS-flow to DRB mappings,
wherein the list of DRBs subject to the status transfer includes a QoS flow mapping list that indicates one or more uplink (UL) QoS flows for which the source base station has initiated the QoS flow to DRB remapping and a Service Data Adaptation Protocol (SDAP) end marker has not been received at the source base station,
power supply circuitry configured to supply power to the source base station.