Patent Description:
<NPL>, discusses QoS flow to DRB remapping. <NPL>, summarizes the outcome of offline discussions on iRAT forwarding solutions.

In aspects of the present disclosure, a method for wireless communications that may be performed by a user equipment (UE) is provided. The method generally includes obtaining an indication that a first data radio bearer (DRB) is released, wherein a first mapping maps a first quality of service (QoS) flow to the first DRB; obtaining a second mapping that maps the first QoS flow to a second DRB; editing service data adaptation protocol (SDAP) headers of uplink protocol data units (PDUs) in an uplink transmission buffer associated with the first DRB, based on a difference between a first configuration of the first DRB and a second configuration of the second DRB; and transmitting the uplink PDUs via the second DRB.

In aspects of the present disclosure, an apparatus for wireless communications is provided. The apparatus generally includes a processor configured to obtain an indication that a first data radio bearer (DRB) is released, wherein a first mapping maps a first quality of service (QoS) flow to the first DRB; obtaining a second mapping that maps the first QoS flow to a second DRB; to edit service data adaptation protocol (SDAP) headers of uplink protocol data units (PDUs) in an uplink transmission buffer associated with the first DRB, based on a difference between a first configuration of the first DRB and a second configuration of the second DRB; and to transmit the uplink PDUs via the second DRB; and a memory coupled with the processor.

In aspects of the present disclosure, an apparatus for wireless communications is provided. The apparatus generally includes means for obtaining an indication that a first data radio bearer (DRB) is released, wherein a first mapping maps a first quality of service (QoS) flow to the first DRB; means for obtaining a second mapping that maps the first QoS flow to a second DRB; editing service data adaptation protocol (SDAP) headers of uplink protocol data units (PDUs) in an uplink transmission buffer associated with the first DRB, based on a difference between a first configuration of the first DRB and a second configuration of the second DRB; and means for transmitting the uplink PDUs via the second DRB.

In aspects of the present disclosure, a computer-readable medium for wireless communications is provided. The computer-readable medium includes instructions that, when executed by a processor, cause the processor to perform operations generally including obtaining an indication that a first data radio bearer (DRB) is released, wherein a first mapping maps a first quality of service (QoS) flow to the first DRB; obtaining a second mapping that maps the first QoS flow to a second DRB; editing service data adaptation protocol (SDAP) headers of uplink protocol data units (PDUs) in an uplink transmission buffer associated with the first DRB, based on a difference between a first configuration of the first DRB and a second configuration of the second DRB; and transmitting the uplink PDUs via the second DRB.

Aspects of the present disclosure provide apparatus, methods, processing systems, and computer readable mediums for avoiding out of order uplink data reception upon data radio bearer (DRB) release, handover to another DRB, or quality of service (QoS) flow addition in wireless communications networks, such as <NUM>th Generation (<NUM>) networks.

Changes may be made in the function and arrangement of elements discussed without departing from the scope of the disclosure as defined by the appended claims.

For clarity, while aspects may be described herein using terminology commonly associated with <NUM>rd Generation (<NUM>) and/or <NUM>th Generation (<NUM>) wireless technologies, aspects of the present disclosure can be applied in other generation-based communication systems, such as <NUM> and later, including NR technologies.

New radio (NR) access (e.g., <NUM> technology) may support various wireless communication services, such as enhanced mobile broadband (eMBB) targeting wide bandwidth (e.g., <NUM> or wider) communications, millimeter wave (mmW) targeting high carrier frequency (e.g., <NUM> or higher) communications, massive machine type communications (mMTC) targeting non-backward compatible machine type communications (MTC) techniques, and/or mission critical targeting ultra-reliable lowlatency communications (URLLC).

For example, the wireless communication network <NUM> may be a New Radio (NR) or <NUM> network. The systems and methods for avoiding out of order uplink data transmission upon data radio bearer (DRB) release or quality of service (QoS) flow addition in wireless communications networks described with respect to <FIG>, <FIG>, and <FIG>, below, may be implemented within wireless communication network <NUM>.

As illustrated in <FIG>, the wireless network <NUM> may include a number of base stations (BSs) <NUM> and other network entities. A BS may be a station that communicates with user equipments (UEs). Each BS <NUM> may provide communication coverage for a particular geographic area. In 3GPP, the term "cell" can refer to a coverage area of a Node B (NB) and/or a Node B subsystem serving this coverage area, depending on the context in which the term is used. In NR systems, the term "cell" and next generation NodeB (gNB), new radio base station (NR BS), <NUM> NB, access point (AP), or transmission reception point (TRP) may be interchangeable. In some examples, the base stations may be interconnected to one another and/or to one or more other base stations or network nodes (not shown) in wireless communication network <NUM> through various types of backhaul interfaces, such as a direct physical connection, a wireless connection, a virtual network, or the like using any suitable transport network.

MIMO configurations in the DL may support up to eight transmit antennas with multi-layer DL transmissions up to eight streams and up to two streams per UE. Multi-layer transmissions with up to two streams per UE may be supported. Aggregation of multiple cells may be supported with up to eight serving cells.

<FIG> illustrates example components of BS <NUM> and UE <NUM> (as depicted in <FIG>), which may be used to implement aspects of the present disclosure. For example, antennas <NUM>, processors <NUM>, <NUM>, <NUM>, and/or controller/processor <NUM> of the UE <NUM> and/or antennas <NUM>, processors <NUM>, <NUM>, <NUM>, and/or controller/processor <NUM> of the BS <NUM> may be used to perform the various techniques and methods described herein, such as those described with respect to <FIG>, <FIG>, and <FIG>.

The <NUM> quality of service (QoS) model is based on QoS flows and supports both QoS flows that require guaranteed flow bit rate (GBR QoS Flows) and QoS flows that do not require guaranteed flow bit rate (non-GBR QoS Flows). At non-access stratum (NAS) level, the QoS flow is thus the finest granularity of QoS differentiation in a protocol data unit (PDU) session. In some embodiments, a QoS flow is identified within a PDU session by a QoS flow identifier (QFI) carried in an encapsulation header over next generation user plane (NG-U).

<FIG> depicts an example of a QoS architecture <NUM> in a next generation radio access network (NG-RAN) <NUM>, which is applicable to both new radio (NR) connected to a <NUM> core network (5GC) and for E-UTRA connected to 5GC. As depicted in <FIG>, for each user equipment (UE) <NUM>, the 5GC <NUM> establishes one or more PDU sessions (e.g., <NUM>). For each UE (e.g., <NUM>), NG-RAN <NUM> establishes one or more data radio bearers (DRB) (e.g., <NUM> and <NUM>) per PDU session (e.g., <NUM>). The NG-RAN <NUM> further maps packets belonging to different PDU sessions (e.g., <NUM>) to different DRBs (e.g., <NUM> and <NUM>).

Generally, the NG-RAN <NUM> establishes at least one default DRB (e.g., <NUM> or <NUM>) for each PDU session (e.g., <NUM>). In this architecture, NAS level packet filters in the UE and in the 5GC associate uplink and downlink packets with QoS flows (e.g., <NUM>, <NUM>, and <NUM>). Further, access stratum (AS)-level mapping rules in the UE and in NG-RAN <NUM> associate UL and DL QoS flows (e.g., <NUM>, <NUM>, and <NUM>) with DRBs (e.g., <NUM> or <NUM>).

NG-RAN <NUM> and 5GC <NUM> ensure quality of service (e.g., reliability and target delay) by mapping packets to appropriate QoS flows (e.g., <NUM>, <NUM>, and <NUM>) and DRBs (e.g., <NUM> or <NUM>). Hence, there is a two-step mapping of IP-flows to QoS flows (NAS) and from QoS flows to DRBs (AS) in the <NUM> quality of service (QoS) model.

At the NAS level, a QoS flow (e.g., <NUM>, <NUM>, and <NUM>) is characterized by a QoS profile provided by 5GC <NUM> to NG-RAN <NUM> and QoS rule(s) provided by 5GC <NUM> to UE <NUM>. The QoS profile is used by NG-RAN <NUM> to determine the treatment on radio interface <NUM> while the QoS rules dictates the mapping between uplink user plane traffic and QoS flows to UE <NUM>. As above, a QoS flow may either be a guaranteed bitrate (GBR) or non-guaranteed bitrate (non-GBR), depending on its profile. The QoS profile of a QoS flow may contain QoS parameters, for instance, for each QoS flow (e.g., <NUM>, <NUM>, and <NUM>). For example, the QoS parameters may include a <NUM> QoS identifier (5QI) and an allocation and retention priority (ARP). In in the case of a GBR QoS flow only, the QoS parameters may additionally include a guaranteed flow bit rate (GFBR) for both uplink and downlink, a maximum flow bit rate (MFBR) for both uplink and downlink, and a maximum packet loss rate for both uplink and downlink. And in the case of non-GBR QoS only, the QoS parameters may additionally include a reflective QoS attribute (RQA). The RQA, when included, indicates that some (not necessarily all) traffic carried on this QoS flow is subject to reflective quality of service (RQoS) at the NAS.

In addition, an aggregate maximum bit rate is associated to each PDU session (session-AMBR) and to each UE (UE-AMBR). The session-AMBR limits the aggregate bit rate that can be expected to be provided across all non-GBR QoS flows for a specific PDU session. The UE-AMBR limits the aggregate bit rate that can be expected to be provided across all non-GBR QoS flows of a UE.

The 5QI is associated to QoS characteristics giving guidelines for setting node specific parameters for each QoS flow. Standardized or pre-configured <NUM> QoS characteristics are derived from the 5QI value and are not explicitly signalled. Signalled QoS characteristics are included as part of the QoS profile. The QoS characteristics may include, for instance, resource type (GBR, delay critical GBR or Non-GBR), priority level, packet delay budget, packet error rate, averaging window, and maximum data burst volume.

At the AS level, the DRB (e.g., <NUM> or <NUM>) defines the packet treatment on radio interface <NUM>. A DRB (e.g., <NUM> or <NUM>) serves packets with the same packet forwarding treatment. The QoS flow (e.g., <NUM>, <NUM>, or <NUM>) to DRB (e.g., <NUM> or <NUM>) mapping by NG-RAN <NUM> is based on QFI and the associated QoS profiles (i.e., QoS parameters and QoS characteristics). Separate DRBs (e.g., <NUM> and <NUM>) may be established for QoS flows (e.g., <NUM>, <NUM>, and <NUM>) requiring different packet forwarding treatment, or several QoS flows (e.g., <NUM>, <NUM>, and <NUM>) belonging to the same PDU session (e.g., <NUM>) can be multiplexed in the same DRB (e.g., <NUM> or <NUM>).

In the uplink, NG-RAN <NUM> may control the mapping of QoS flows (e.g., <NUM>, <NUM>, and <NUM>) to DRBs (e.g., <NUM> and <NUM>) in different ways. First, NG-RAN <NUM> may implement reflective mapping in which for each DRB (e.g., <NUM> or <NUM>), UE <NUM> monitors the QFI(s) of the downlink packets and applies the same mapping in the uplink; that is, for a DRB (e.g., <NUM> or <NUM>), the UE <NUM> maps the uplink packets belonging to the QoS flows (e.g., <NUM>, <NUM>, and <NUM>) corresponding to the QFI(s) and PDU session (e.g., <NUM>) observed in the downlink packets for that DRB (e.g., <NUM> or <NUM>). To enable this reflective mapping, NG-RAN <NUM> marks downlink packets over radio interface <NUM> with QFI. Second, NG-RAN may implement explicit configuration in which besides the reflective mapping, NG-RAN <NUM> may configure by RRC signaling an uplink "QoS flow to DRB mapping. " Generally, UE <NUM> applies the latest update of the mapping rules, regardless of whether the update to the mapping rules is performed via reflecting mapping or explicit configuration.

In the downlink, the QFI is signaled by NG-RAN <NUM> over radio interface <NUM> for the purpose of RQoS and if neither NG-RAN <NUM>, nor the NAS (as indicated by the RQA) intend to use reflective mapping for the QoS flow(s) (e.g., <NUM>, <NUM>, or <NUM>) carried in a DRB (e.g., <NUM> or <NUM>), then no QFI is signaled for that DRB (e.g., <NUM> or <NUM>) over radio interface <NUM>. In the uplink, NG-RAN <NUM> can configure UE <NUM> to signal QFI over radio interface <NUM>.

For each PDU session (e.g., <NUM>), a default DRB (e.g., <NUM> or <NUM>) is configured. If an incoming uplink packet matches neither an RRC configured nor a reflective "QoS Flow ID to DRB mapping", the UE maps that packet to the default DRB (e.g., <NUM> or <NUM>) of PDU session <NUM>.

Within each PDU session (e.g., <NUM>), it is up to NG-RAN <NUM> how to map multiple QoS flows (e.g., <NUM>, <NUM>, and/or <NUM>) to a DRB (e.g., <NUM> or <NUM>). NG-RAN <NUM> may map a GBR flow and a non-GBR flow, or more than one GBR flow to the same DRB (e.g., <NUM> or <NUM>). The timing of establishing non-default DRB(s) between NG-RAN <NUM> and UE <NUM> for QoS flow configured during establishing a PDU session (e.g., <NUM>) can be different from the time when the PDU session (e.g., <NUM>) is established. NG-RAN <NUM> determines when non-default DRBs are established.

<FIG> depicts an example header <NUM> of a conventional SDAP PDU, which includes a "D/C" bit <NUM>, an "R" bit <NUM>, and QFI bits <NUM> (i.e., a QFI field of the SDAP header of the SDAP PDU), which together make up an octet of size one byte. In some cases, the "D/C" bit <NUM> indicates whether the SDAP PDU <NUM> is an SDAP data PDU or an SDAP control PDU. The R bit <NUM> is a reserved bit and, in some cases, may be set to zero. Additionally, the QFI bits <NUM> indicate the ID of the QoS flow to which the SDAP SDU <NUM> belongs. For example, in an uplink packet, QFI bits <NUM> may refer to a QoS flow with QFI=<NUM>.

<FIG> illustrates an uplink mapping <NUM> for end-to-end QoS enforcement, according to aspects of the present disclosure. In the present disclosure, a service data flow (SDF) may be viewed as the data, packets, and/or frames from one set of applications on a smartphone, but the present disclosure is not so limited and applies to all types of SDFs in a wireless communications network. According to aspects of the present disclosure, a UE (e.g., UE <NUM> or UE <NUM>) can have multiple PDU sessions <NUM>, <NUM>, and <NUM>. In the PDU session <NUM>, two SDFs <NUM> and <NUM> are established. Packets from both SDFs <NUM> and <NUM> are matched to the default QoS flow <NUM> for PDU session <NUM>. The default QoS flow for PDU session <NUM> has a QoS flow identifier (QFI) of <NUM>. The packets of the QoS flow are mapped to the default DRB <NUM> of the PDU session <NUM> for transmission. In the PDU session <NUM>, five SDFs <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> are established. Packets from SDF <NUM> are matched to the QoS flow <NUM>, which has a QFI of <NUM>. The packets of the QoS flow QFI=<NUM> are mapped to the DRB <NUM> for transmission. Packets from SDFs <NUM> and <NUM> are matched to the default QoS flow <NUM> for PDU session <NUM>. The default QoS flow for PDU session <NUM> has a QFI of <NUM>. The packets of the QoS flow QFI=<NUM> are mapped to the default DRB <NUM> of the PDU session <NUM> for transmission. Packets from SDFs <NUM> and <NUM> are matched to the QoS flow <NUM>, which has a QFI of <NUM>. The packets of the QoS flow QFI=<NUM> are also mapped to the default DRB <NUM> of the PDU session <NUM> for transmission. In the unstructured PDU session <NUM>, packets are mapped to the default QoS flow <NUM> for PDU session <NUM>. The default QoS flow for the unstructured PDU session has a QFI=<NUM>. The packets of the QoS flow QFI=<NUM> are mapped to the default DRB <NUM> of the PDU session <NUM> for transmission.

<FIG> is a diagram <NUM> of a call flow when an NG-RAN <NUM> configures a UE <NUM> to change the AS mapping of an existing QoS flow from one DRB to another DRB, via RRC signalling. The configuration change and packet flows are illustrated in <FIG>, described below. UE <NUM> (shown in <FIG> and <FIG>) may be an example of UE <NUM>, and the components of UE <NUM> shown in <FIG> may perform operations described in the call flow diagram <NUM>.

The call flow shown in diagram <NUM> begins with the UE <NUM> in RRC_Connected mode, registered with the <NUM> core network, and camped on an NR cell. The UE has established a PDU session with PDU session type of IPv4, IPv6, IPv4v6, or Ethernet. At <NUM>, the UE establishes a QoS flow with QFI=<NUM> during PDU session establishment. RRC signaling (e.g., from the NG-RAN) configures a QoS flow, QFI1, to be mapped to a first DRB, DRB1. The UE transfers UL and DL application data via QFI1 and DRB1.

At <NUM>, The NG-RAN sends an RRC reconfiguration message to the UE. The RRC reconfiguration message contains a new mapping such that QFI1 is mapped to a second DRB, DRB2. The new QFI to DRB mapping is conveyed via an information element (IE): RadioBearerConfig -> DRB-ToAddMod -> sdap-Config. The UE sends an RRC Reconfiguration Complete message to acknowledge the NG-RAN's RRC message at <NUM>.

Next, at <NUM>, the UE SDAP layer maps all new QFI1 uplink data to DRB2. That is, data arriving at the UE SDAP layer is mapped to DRB2, according to the new QFI to DRB mapping. Thus, in the remainder of the call flow <NUM>, packets of QFI1 (e.g., Pkt-<NUM> and Pkt-<NUM>) are mapped to DRB2.

At <NUM>, after the UE has confirmed that no new QFI1 uplink data is mapped to DRB1, the UE creates an SDAP control PDU for QFI1 and puts the SDAP control PDU into the DRB1 layer-<NUM> transmission buffer. The SDAP control PDU is the last PDCP PDU of QFI1 in DRB1. In <FIG>, the SDAP control PDU is put after Pkt-<NUM> in DRB1. According to aspects of the present disclosure, the PDCP entity in the UE cannot differentiate the SDAP control PDU from an SDAP data PDU, so both are treated in the same way by PDCP and their order is preserved by the PDCP layer, i.e., the PDCP layer will ensure that the SDAP control PDU is the last PDCP PDU for QFI1 in DRB1. Therefore, the SDAP control PDU serves as the end-marker in the QFI re-mapping.

Then, at <NUM>, the UE may have already mapped some QFI1 uplink data to DRB1 (e.g., Pkt-<NUM> and Pkt-<NUM>, shown in <FIG>) and put the QFI1 uplink data into the layer-<NUM> transmission buffer of DRB1. The UE still transmits all such QFI1 data via DRB1. In <FIG>, Pkt-<NUM> and Pkt-<NUM> are already mapped to DRB1.

At <NUM>, due to hybrid automatic retransmission request (HARQ) and logical channel prioritization (LCP) (e.g., DRB2 may be higher priority than DRB1 in MAC layer scheduling), NG-RAN may receive the DRB2 data described at <NUM> before receiving the DRB1 data described at <NUM>, but the NG-RAN begins delivering DRB2 data to upper layers only after receiving the SDAP end-marker control PDU mentioned above. This means that the NG-RAN delivers all DRB1 data to upper layers before delivering any DRB2 data, for QFI1 in the uplink. In <FIG>, Pkt-<NUM> and Pkt-<NUM> (from DRB2) may be received by the NG-RAN earlier than Pkt-<NUM>, Pkt-<NUM>, or the SDAP control PDU. However, the NG-RAN will deliver Pkt-<NUM> to upper layers only after the SDAP control PDU is received.

At <NUM>, the NG-RAN re-maps the DL QFI=<NUM> data from DRB1 to DRB2, which is up to NG-RAN implementation. This can happen at any time in the call flow.

According to aspects of the present disclosure, the UE uses an SDAP end-marker control PDU to indicate that the configuration change has been applied. During the call flow, the old DRB (DRB1) is not released.

<FIG> is a diagram <NUM> illustrating an uplink mapping during the operations illustrated with the call flow <NUM>, shown in <FIG>. When the operations begin, the UE <NUM> establishes a QoS flow <NUM> with QFI=<NUM> (i.e., QFI1) during PDU session establishment. RRC signaling (e.g., from the NG-RAN) configures the QoS flow, QFI1, to be mapped to a first DRB <NUM>, DRB1. The UE transfers UL and DL application data (e.g., Pkt-<NUM><NUM> and Pkt-<NUM><NUM>) from an application layer <NUM> via QFI1 and DRB1. As mentioned above with reference to <NUM> in <FIG>, the UE receives an RRC reconfiguration message that contains a new mapping such that QFI1 is mapped to a second DRB <NUM>, DRB2. A service data adaptation protocol (SDAP) layer <NUM> at the UE creates an SDAP control PDU <NUM> for QFI1 and puts the SDAP control PDU into the DRB1 layer-<NUM> transmission buffer. The application layer generates additional application data, packets Pkt-<NUM><NUM> and Pkt-<NUM><NUM>. The SDAP layer maps packets Pkt-<NUM> and Pkt-<NUM> to DRB2, according to the new mapping received in the RRC reconfiguration message.

According to aspects of the present disclosure, some DRBs (e.g., DRB1, shown in <FIG>) may be released while there are still residual UL SDAP data PDUs in the UE buffers of the released DRBs. The DRBs may be released due to, e.g., handover from a <NUM> network that uses SDAP headers on PDUs to a <NUM> or <NUM> network that does not use SDAP headers on PDUs, PDU session user plane deactivation (i.e., all DRBs of an existing PDU session are released), RRC release (i.e., a command from the network to release the DRB), or radio link failure (RLF). The UE may then perform a relevant procedure to establish DRBs again. For example, a UE has data to transmit via a DRB, DRB1, and the UE is assigned a new DRB, DRB2. DRB <NUM> and DRB2 can have different configurations. For example, in a first configuration for data of two QoS flows, QFI1 and QFI2, DRB <NUM> is configured to use uplink SDAP headers, and both QFI1 and QFI2 are mapped to DRB1. In the example, the UE receives a new configuration for the QFI1 and QFI2 data. In the new configuration, a new DRB, DRB2, is configured with no uplink SDAP header; QFI1 is mapped to DRB2; another new DRB, DRB3, is configured to not use uplink SDAP headers; and QFI2 is mapped to DRB3. In the example, one problem is that the QFI1 and QFI2 data packets in DRB1's buffer are formatted based on the old configuration (i.e., DRB1's configuration). Such QFI1 packets cannot be directly transmitted via DRB2, because their format is not compliant with DRB2's configuration and the receiver cannot process these packets correctly if they are directly transmitted via DRB2. In the example, a second problem is that, according to the new configurations, QFI1 packets can only be transmitted via the PDCP entity for DRB2, and QFI2 packets can only be transmitted via the PDCP entity for DRB3. However, QFI1 packets and QFI2 packets may be mixed in the same buffer of DRB1. The lower layer (PDCP layer) of the protocol stack does not know which packets are from the QFI1 QoS flow and which packets are from the QFI2 QoS flow.

In previously known techniques, a UE discards UL data packets in the released DRB if a new configured DRB has a different UL SDAP header configuration (e.g., the released DRB uses SDAP headers and the new DRB does not use SDAP headers) and a different QFI-to-DRB mapping than the released DRB. Also, in previously known techniques, if the old configuration uses UL SDAP headers and the new configuration does not use UL SDAP headers, then the receiving gNB treats the SDAP headers (i.e., from the packets configured using the old configuration) as user data, and hence, the upper layer (e.g., TCP/UDP/IP) protocol will find the data format invalid and discard the packets. In addition, in previously known techniques, the UL data may be out of order at the receiver side, due to the previously mentioned packet discarding. Thus, it is desirable to develop techniques to avoiding out of order uplink data reception upon DRB release or handover to another DRB.

<FIG> is a flow diagram illustrating operations <NUM> for wireless communications that may be performed by a UE (e.g., UE <NUM>, shown in <FIG> and <FIG>), to avoid out of order uplink data reception upon DRB release, in accordance with aspects of the present disclosure.

At block <NUM>, operations <NUM> begin with the UE obtaining an indication that a first data radio bearer (DRB) is released, wherein a first mapping maps a first quality of service (QoS) flow to the first DRB. For example, UE <NUM> (shown in <FIG> and <FIG>) is initially connected to a <NUM> core network (e.g., a <NUM> network operated via BS 110a, shown in <FIG>) via a first DRB (DRB1) that is a <NUM> DRB that is configured to not use uplink SDAP headers on PDUs and the UE receives a handover (HO) command to handover to a <NUM> core network (e.g., a <NUM> network operated via BS 110b, shown in <FIG>). Receiving the handover command is an example of a UE obtaining an indication that a first DRB is released.

Operations <NUM> continue at block <NUM> with the UE obtaining a second mapping that maps the first QoS flow to a second DRB. Continuing the example from above, the UE is configured by the network (e.g., in the HO command) to map DRB1 (i.e., the first DRB) to a QoS flow of a second DRB (DRB2, e.g., a <NUM> DRB that is configured to use SDAP headers on PDUs).

At block <NUM>, operations <NUM> continue with the UE editing service data adaptation protocol (SDAP) headers of uplink protocol data units (PDUs) in an uplink transmission buffer associated with the first DRB, based on a difference between a first configuration of the first DRB and a second configuration of the second DRB. Continuing the example from above, the UE edits each SDAP PDU in a transmission buffer of the UE that was previously mapped to DRB1 by adding an SDAP header to that PDU. The UE may move the edited PDUs (i.e., the PDUs with the added SDAP headers) to the transmission buffer for DRB2. The UE then transmits the edited PDUs via DRB2.

Operations <NUM> continue at block <NUM> with the UE transmitting the uplink PDUs via the second DRB. Continuing the example from above, the UE transmits the edited PDUs (i.e., the PDUs with the added SDAP headers) via the second DRB (DRB2).

A UE performing operations <NUM> (described above with reference to <FIG>) is described in the following example. A UE (e.g., UE <NUM>, shown in <FIG>) is initially connected to a <NUM> core network (e.g., a <NUM> network operated via BS 110a, shown in <FIG>) via a <NUM> DRB (DRB1). The UE then hands over to a <NUM> core network (e.g., a <NUM> network operated via BS 110b, shown in <FIG>). The UE is configured by the network to map the QoS flows of <NUM> DRB1 to a <NUM> DRB (e.g., <NUM> DRB2). DRB1 is configured to use uplink SDAP headers on SDAP PDUs, while DRB2 is configured to not use SDAP headers on PDUs. In this example, the UE can perform operations <NUM>, to edit each SDAP PDU mapped to DRB1 in the UE transmission buffer by removing an SDAP header from that PDU, and then move the edited PDUs (i.e., the PDUs after they have had the SDAP headers removed) to a transmission buffer for DRB2, prior to transmitting the edited PDUs via DRB2.

According to aspects of the present disclosure, a UE performing operations <NUM> does not discard UL data packets in the released DRB (i.e., the first DRB of block <NUM>) if a new configured DRB has a different UL SDAP header configuration and QFI-to-DRB mapping than the released DRB. Because the UE does not discard UL data, the UL data is received in order (i.e., in the correct sequence) at the receiver side.

In aspects of the present disclosure, if the first configuration of the first DRB (i.e., the first configuration in block <NUM>) indicates that uplink SDAP PDUs do not have SDAP headers (e.g., the first DRB is a DRB of a <NUM> or <NUM> network) and the second configuration of the second DRB (i.e., the second configuration in block <NUM>) indicates that uplink SDAP PDUs have SDAP headers (e.g., the second DRB is a DRB of a <NUM> network), then for each existing UL SDAP data PDU in a DRB uplink buffer of the UE, the UE adds an uplink SDAP header to the SDAP data PDU; sets the "QFI" field of the UL SDAP header to the QFI value of the QoS flow (i.e., the QoS flow in block <NUM>); sets other fields of the added UL SDAP header based on a related specification, such as 3GPP TS. <NUM>; and transmits the updated UL SDAP data PDU via the second DRB.

According to aspects of the present disclosure, if the first configuration of the first DRB (i.e., the first configuration in block <NUM>) indicates that uplink SDAP PDUs have SDAP headers and the second configuration of the second DRB (i.e., the second configuration in block <NUM>) indicates that uplink SDAP PDUs do not have SDAP headers, then for each existing UL SDAP data PDU in a DRB uplink buffer of the UE, the UE removes uplink SDAP headers from the SDAP data PDU and transmits the updated UL SDAP data PDU via the second DRB.

In previously known techniques, a UE may receive a NAS PDU session modification command to add a new QoS flow, QFI1, (i.e., the UE does not have the QoS flow before getting the NAS PDU session modification command), by adding one or multiple QoS rules associated with QFI1, and the UE may send packets out of order by using the rules associated with QFI1 before the UE obtains a QFI-to-DRB mapping rule for QFI1. This may occur when the gNB does not configure a QFI-to-DRB mapping at exactly the same TTI as the network configures the UE with new QoS flows, which can happen frequently, since these two configurations may come from different network entities. In previously known techniques, when the UE receives a NAS PDU session modification command to add a new QoS flow (QFI1) before the UE obtains a QFI-to-DRB mapping rule for QFI1, the UE will map QFI1 to the default DRB. When the RRCReconfiguration message containing a configuration to map QFI1 to another DRB (e.g., DRB2) is received by the UE, then the UE locally remaps QFI1 to the other DRB (DRB2). However, the network may not expect such a remapping. In-order delivery is only tracked within a DRB, but QFI1 packets are transmitted over both DRB1 and DRB2 during the remapping transition time, and hence data packets of QFI1 may be received out of their original order. It is therefore desirable to develop techniques to avoid out of order uplink data reception upon QoS flow addition.

<FIG> is a flow diagram illustrating operations <NUM> for wireless communications that may be performed by a UE (e.g., UE <NUM>, shown in <FIG> and <FIG>) to avoid out of order uplink data reception upon QoS flow addition.

At block <NUM>, operations <NUM> begin with the UE receiving a non-access stratum (NAS) protocol data unit (PDU) session modification command for a PDU session that adds a new quality of service (QoS) flow having a first QoS flow identifier (QFI). For example, UE <NUM> (shown in <FIG>) receives a NAS PDU session modification command message for a PDU session that adds a new QoS flow with a QFI=<NUM> (i.e., a first QFI).

Operations <NUM> continue at block <NUM> with the UE determining that the UE does not have an uplink QoS flow to data radio bearer (DRB) mapping rule for the QoS flow having the first QFI. Continuing the example from above, the UE determines that the UE does not have an uplink QoS flow to DRB mapping rule for the QoS with QFI=<NUM>.

Operations <NUM> continue at block <NUM> with the UE, preventing, during a period subsequent to the determination, a service data adaptation protocol (SDAP) layer of the UE from processing and transmitting uplink data associated with the QoS flow having the first QFI. Continuing the example from above, the UE, while the first timer is counting down the period, prevents an SDAP layer of the UE from processing and transmitting uplink data associated with the QoS flow having QFI=<NUM>.

According to aspects of the present disclosure, a UE performing operations <NUM> may cause a receiver to receive packets of the QoS flow having the first QFI of block <NUM> in the packets' original order.

In aspects of the present disclosure, a UE performing operations <NUM> may receive a QoS flow to DRB mapping rule for the QoS flow having the first QFI (i.e., the QoS flow in block <NUM>). The UE may then process and transmit uplink data associated with the QoS flow having the first QFI using the received QoS flow to DRB mapping rule.

According to aspects of the present disclosure, a UE performing operations <NUM> may, at the end of the period (i.e., the period in block <NUM>), determine a QoS flow to DRB mapping rule for the QoS flow having the first QFI (i.e., the QoS flow in block <NUM>).

In aspects of the present disclosure, a UE performing operations <NUM> may start a timer at the beginning of the period (i.e., the period in block <NUM>) and determine that the period ends when the timer expires.

In aspects of the present disclosure, a UE determining a QoS flow to DRB mapping rule for the QoS flow having the first QFI (i.e., the QoS flow in block <NUM>) may determine the DRB mapping rule to be to map PDUs of the QoS flow having the first QFI to a default DRB of the PDU session.

According to aspects of the present disclosure, a UE determining a QoS flow to DRB mapping rule for the QoS flow having the first QFI (i.e., the QoS flow in block <NUM>) may determine that the PDU session does not have a default DRB and then determine the DRB mapping rule to be to map PDUs of the QoS flow having the first QFI to a non-default DRB of the PDU session.

In previously known techniques, if a PDU session has non-default DRBs and no default DRB, and at least one QoS flow of the PDU session has no QoS flow to DRB mapping rule configured, then UE behavior is not defined, and the UE will typically discard uplink user data of the QoS flow(s) which are not mapped to a DRB. While this is a network error and should be rare in a well-configured <NUM> standalone (SA) network, it may happen in initial SA deployments where the network configuration may be not optimal. It is therefore desirable to develop techniques to prevent a UE from discarding uplink user data under these conditions.

<FIG> is a flow diagram illustrating operations <NUM> for wireless communications that may be performed by a UE (e.g., UE <NUM>, shown in <FIG> and <FIG>) to avoid discarding UL user data when the UE has a PDU session having non-default DRBs, no default DRB, and at least one QoS flow that is not mapped to any DRB, according to aspects of the present disclosure.

At block <NUM>, operations <NUM> begin with the UE receiving a configuration of a protocol data unit (PDU) session, wherein the configuration does not identify a default data radio bearer (DRB) of the PDU session and a quality of service (QoS) flow of the PDU session does not have a QoS flow to DRB mapping rule configured. For example, UE <NUM> (shown in <FIG> and <FIG>) receives a configuration of a PDU session (e.g., for a web-browsing application), wherein the configuration does not identify a default DRB of the PDU session and a QoS flow of the PDU session does not have a QoS flow to DRB mapping rule configured.

At block <NUM>, operations <NUM> continue with the UE, subsequent to a period elapsing after receiving the configuration, determining if the configuration still holds. Continuing the example from above, when the timer (i.e., the timer started in block <NUM>) expires, the UE determines if the configuration (i.e., the configuration received in block <NUM>) still holds (e.g., the UE determines if a replacement configuration has been received).

Operations <NUM> continue at block <NUM> with the UE, when the configuration still holds: when a DRB of the PDU session that contains a QoS flow associated with the default QoS rule is configured to use uplink service data adaptation protocol (SDAP) headers, mapping the QoS flow to the DRB, and when the DRB of the PDU session that contains a QoS flow associated with the default QoS rule is not configured to use uplink SDAP headers, mapping the QoS flow to another DRB that does not contain a guaranteed bit rate (GBR) QoS flow and is configured to use uplink SDAP headers. Continuing the example from above, if the UE determined the configuration still held in block <NUM>, then: when a DRB of the PDU session that contains a QoS flow associated with the default QoS rule is configured to use uplink service data adaptation protocol (SDAP) headers, the UE maps the QoS flow (i.e., the QoS flow in block <NUM> that does not have a QoS flow to DRB mapping rule configured) to the DRB (i.e., the DRB that is configured to use uplink SDAP headers and contains a QoS flow associated with the default QoS rule), and when the DRB of the PDU session that contains a QoS flow associated with the default QoS rule is not configured to use uplink SDAP headers, mapping the QoS flow (i.e., the QoS flow in block <NUM> that does not have a QoS flow to DRB mapping rule configured) to another DRB that does not contain any guaranteed bit rate (GBR) QoS flow and is configured to use uplink SDAP headers.

According to aspects of the present disclosure, a UE performing operations <NUM> will not discard uplink user data when:.

According to aspects of the present disclosure, a UE performing operations <NUM> may determine the length of the period (i.e., the period in block <NUM>) based on a wireless network communications standard.

According to aspects of the present disclosure, a UE performing operations <NUM> may determine the length of the period (i.e., the period in block <NUM>) based on a configuration received from the network (i.e., received from a base station).

<FIG> illustrates a communications device <NUM> that may include various components (e.g., corresponding to means-plus-function components) configured to perform operations for the techniques disclosed herein, such as the operations illustrated in <FIG>, <FIG>, and <FIG>. The transceiver <NUM> is configured to transmit and receive signals for the communications device <NUM> via an antenna <NUM>, such as the various signal described herein.

The processing system <NUM> includes a processor <NUM> coupled to a computer-readable medium/memory <NUM> via a bus <NUM>. In certain aspects, the computer-readable medium/memory <NUM> is configured to store instructions that when executed by processor <NUM>, cause the processor <NUM> to perform the operations illustrated in <FIG>, <FIG>, and <FIG>, or other operations for performing the various techniques discussed herein.

In certain aspects, the processing system <NUM> further includes a receiving component <NUM> for performing the operations illustrated in <FIG>, <FIG>, and <FIG>. Additionally, the processing system <NUM> includes a transmitting component <NUM> for performing the operations illustrated in <FIG>, <FIG>, and <FIG>. Additionally, the processing system <NUM> includes a determining component <NUM> for performing the operations illustrated in <FIG>, <FIG>, and <FIG>. Additionally, the processing system <NUM> includes a deriving component <NUM> for performing the operations illustrated in <FIG>, <FIG>, and <FIG>. The receiving component <NUM>, transmitting component <NUM>, determining component <NUM>, and deriving component <NUM> may be coupled to the processor <NUM> via bus <NUM>. In certain aspects, the receiving component <NUM>, transmitting component <NUM>, determining component <NUM>, and deriving component <NUM> may be hardware circuits. In certain aspects, the receiving component <NUM>, transmitting component <NUM>, determining component <NUM>, and deriving component <NUM> may be software components that are executed and run on processor <NUM>.

The preceding description is provided to enable any person skilled in the art to practice the various aspects described herein.

For example, instructions for performing the operations described herein and illustrated in <FIG>, <FIG>, and <FIG>.

Claim 1:
A method (<NUM>) of wireless communications performed by a user equipment, UE, comprising:
obtaining (<NUM>) an indication that a first data radio bearer, DRB, is released, wherein a first mapping maps a first quality of service, QoS, flow to the first DRB, wherein a QoS flow is a finest granularity of QoS differentiation in a protocol data unit, PDU, session;
obtaining (<NUM>) a second mapping that maps the first QoS flow to a second DRB;
editing (<NUM>) service data adaptation protocol, SDAP, headers of uplink protocol data units, PDUs, in an uplink transmission buffer associated with the first DRB, based on a difference between a first configuration of the first DRB and a second configuration of the second DRB, wherein one of the first configuration and the second configuration indicates that uplink SDAP PDUs do not have SDAP headers and the other of the first configuration and the second configuration indicates that uplink SDAP PDUs have SDAP headers and editing the SDAP headers comprises adding an SDAP header to or deleting an SDAP header from each uplink PDU in the uplink transmission buffer, such that the uplink PDUs correspond to the second configuration; and
transmitting (<NUM>) the uplink PDUs via the second DRB.