Systems and methods for in-order delivery in downlink during handover
AssigneeQUALCOMM Incorporated
InventorSai Yiu Duncan Ho
Life of this patent
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Abstract
Systems and methods that manage effects of discarded SDUs during handover. Aspects of the subject innovation maintain order for arrival of PDCP SDUs when a UE encounters a lost PDCP, which has resulted from a dropped SDU at the source eNB—before assignment of an associated PDCP SN. By initially assigning all SDUs corresponding PDCP SNs, a PDCP SN gap or hole can then be encountered upon dropping of a PDCP SDU. To manage PDCP SN gaps or holes thus generated, an internal time out can be designated to terminate an associated UE's delay for such SN hole(s) via a time out. Other aspects enable the source eNB to send a PDCP Status Message to the UE (via the target eNB) to abort the SN gaps or holes resulting from a dropped PDCP SN.
Claims35
A method of maintaining order of arrival for packet data convergence protocol (PDCP) service data units (SDUs) during a hand over from a source evolved Node B (eNB) to a target eNB comprising:
- assigning a packet data convergence protocol sequence number (PDCP SN) to a service data unit (SDU), the PDCP SN being offset to a General Packet Radio Services tunneling protocol sequence number (GTP-U SN) for the SDU by a predetermined offset value;
- supplying the predetermined offset value to the target eNB during the hand over;
- detecting drop of a further SDU at the source eNB before assignment of an associated PDCP SN to the further SDU at the source eNB;
- informing, by the source eNB, a user equipment (UE) of the drop of the further SDU;
- and
- discarding the associated PDCP SN at the source eNB.
A wireless communications apparatus, comprising:
- at least one processor configured to:
- designate for service data units (SDUs), packet data convergence protocol sequence numbers (PDCP SNs) that are offset to General Packet Radio Services tunneling protocol sequence numbers (GTP-U SNs) of the SDUs by a predetermined offset value;
- verify drop of a service data unit (SDU) at a source evolved Node B (eNB) before assignment of an associated packet data convergence protocol sequence number (PDCP SN) to the dropped SDU at the source eNB;
- supply the predetermined offset value to a target eNB;
- inform, by the source eNB, a user equipment (UE) of the drop of the SDU;
- and
- discarding the associated PDCP SN at the source eNB.
A wireless communication apparatus for maintaining order of arrival for packet data convergence protocol (PDCP) service data units (SDUs) during a hand over from a source evolved Node B (eNB) to a target eNB comprising:
- means for assigning a service data unit (SDU) a PDCP sequence number (SN) that is offset to a General Packet Radio Services tunneling protocol (GTP-U) SN associated with the SDU by a predetermined offset value;
- means for supplying the offset value to the target eNB during the hand over;
- means for detecting drop of an additional SDU at the source eNB before assignment of an associated PDCP SN to the additional SDU at the source eNB;
- means for informing, by the source eNB, a user equipment (UE) of the drop of the additional SDU;
- and
- means for discarding the associated PDCP SN at the source eNB.
A computer program product comprising:
- a non-transitory computer-readable medium comprising:
- code for causing at least one computer to designate for a service data unit (SDU) a packet data convergence protocol sequence number (PDCP SN) that is offset to a General Packet Radio Services tunneling protocol sequence number (GTP-U SN) associated with the SDU by a predetermined offset value;
- code for detecting drop of an additional SDU at a source evolved Node B (eNB) before assignment of the associated PDCP SN to the additional SDU at the source eNB;
- code for informing, by the source eNB, a user equipment (UE) of a drop of the additional SDU;
- and
- code for discarding the associated PDCP SN at the source eNB.
A method of maintaining order of arrival for packet data convergence protocol (PDCP) service data units (SDUs) during a hand over from a source evolved Node B (eNB) to a target eNB comprising:
- receiving a packet data convergence protocol sequence number (PDCP SN) by a service data unit (SDU), the PDCP SN being offset to a General Packet Radio Services (GPRS) tunneling protocol sequence number (GTP-U SN) for the SDU by a predetermined offset value;
- detecting drop of a further SDU at the source eNB before assignment of an associated PDCP SN to the further SDU at the source eNB;
- notifying, by the source eNB, a user equipment (UE) of the drop of the further SDU;
- and
- discarding the associated PDCP SN at the source eNB.
Dependencies are inferred from the claim text.