WO2024230027A1

WO2024230027A1 - Data transport method

Info

Publication number: WO2024230027A1
Application number: PCT/CN2023/117346
Authority: WO
Inventors: Yuang FENG; Menghan WANG; Jinguo Zhu
Original assignee: ZTE Corp
Current assignee: ZTE Corp
Priority date: 2023-09-06
Filing date: 2023-09-06
Publication date: 2024-11-14
Anticipated expiration: 2026-03-06

Abstract

A wireless communication method for use in a wireless network node is disclosed. The method comprises transmitting, to a wireless terminal, a data radio bearer (DRB) mapping rule indicating that a first quality-of-service (QoS) flow of a first protocol data unit (PDU) session is mapped to a common DRB to which a second QoS flow of a second PDU session is mapped.

Description

DATA TRANSPORT METHOD

TECHNICAL FIELD

This document is directed generally to wireless communications, and in particular to 5G communications.

BACKGROUND

In an existing 5GS (5G system) , each DRB (data radio bearer) is used to transport QoS (quality-of-service) flow (s) belonging to the same PDU (protocol data unit) session. In other words, single DRB cannot be shared by QoS flow (s) of a PDU session #1 and QoS flow (s) of another PDU session #2, resulting in inefficient use of scarce wireless resources of the air interface.

SUMMARY

This document relates to methods, systems, and devices for transmitting data, and in particular to methods, systems, and devices for allowing one DRB to be shared by QoS flows of different PDU sessions.

The present disclosure relates to a wireless communication method for use in a wireless network node. The method comprises:

transmitting, to a wireless terminal, a data radio bearer (DRB) mapping rule indicating that a first quality-of-service (QoS) flow of a first protocol data unit (PDU) session is mapped to a common DRB to which a second QoS flow of a second PDU session is mapped.

Various embodiments may preferably implement the following features:

Preferably, the wireless communication method further comprises modifying a maximum bit rate (MBR) of the common DRB based on the first QoS flow of the first PDU session.

Preferably, the first QoS flow of the first PDU session is a non-guaranteed-bit-rate QoS flow.

Preferably, the wireless communication method further comprises:

receiving, from the wireless terminal, uplink data on the common DRB, a PDU session identifier of the uplink data and a QoS flow identifier (QFI) of the uplink data,

determining an N3 tunnel based on the PDU session ID of the uplink data, and

transmitting, to a user plane function, the uplink data by using the determined N3 tunnel.

Preferably, the wireless communication method further comprises:

receiving, from a user plane function, downlink data configured to be transmitted via the common DRB, and

transmitting, to the wireless terminal, the downlink data on the common DRB, a PDU session identifier of the downlink data and a QoS flow identifier (QFI) of the downlink data.

Preferably, the PDU session identifier and the QFI are in a Service Data Adaptation Protocol (SDAP) header.

receiving, from a wireless network node, a data radio bearer (DRB) mapping rule indicating that a first quality-of-service (QoS) flow of a first protocol data unit (PDU) session is mapped to a common DRB to which a second QoS flow of a second PDU session is mapped.

Various embodiments may preferably implement the following features:

Preferably, a maximum bit rate (MBR) of the common DRB is modified based on the first QoS flow of the first PDU session.

Preferably, the wireless communication method further comprises: transmitting, to the wireless network node, uplink data on the common DRB, a PDU session identifier of the uplink data and a QoS flow identifier (QFI) of the uplink data.

Preferably, the wireless communication method further comprises: receiving, from the wireless network node, downlink data on the common DRB, a PDU session identifier of the downlink data and a QoS flow identifier (QFI) of the downlink data.

The present disclosure relates to a wireless network node. The wireless network node comprises:

a communication unit, configured to transmit, to a wireless terminal, a data radio bearer (DRB) mapping rule indicating that a first quality-of-service (QoS) flow of a first protocol data unit (PDU) session is mapped to a common DRB to which a second QoS flow of a second PDU session is mapped.

Various embodiments may preferably implement the following feature:

Preferably, the wireless network node further comprises a processor configured to perform any of the aforementioned wireless communication methods.

The present disclosure relates to a wireless terminal. The wireless terminal comprises:

a communication unit, configured to receive, from a wireless network node, a data radio bearer (DRB) mapping rule indicating that a first quality-of-service (QoS) flow of a first protocol data unit (PDU) session is mapped to a common DRB to which a second QoS flow of a second PDU session is mapped.

Various embodiments may preferably implement the following feature:

Preferably, the wireless terminal further comprises a processor configured to perform any of the aforementioned wireless communication methods.

The present disclosure relates to a computer program product comprising a computer-readable program medium code stored thereupon, the code, when executed by a processor, causing the processor to implement a wireless communication method recited in any one of foregoing methods.

The exemplary embodiments disclosed herein are directed to providing features that will become readily apparent by reference to the following description when taken in conjunction with the accompany drawings. In accordance with various embodiments, exemplary systems, methods, devices and computer program products are disclosed herein. It is understood, however, that these embodiments are presented by way of example and not limitation, and it will be apparent to those of ordinary skill in the art who read the present disclosure that various modifications to the disclosed embodiments can be made while remaining within the scope of the present disclosure.

Thus, the present disclosure is not limited to the exemplary embodiments and applications described and illustrated herein. Additionally, the specific order and/or hierarchy of steps in the methods disclosed herein are merely exemplary approaches. Based upon design preferences, the specific order or hierarchy of steps of the disclosed methods or processes can be re-arranged while remaining within the scope of the present disclosure. Thus, those of ordinary skill in the art will understand that the methods and techniques disclosed herein present various steps or acts in a sample order, and the present disclosure is not limited to the specific order or hierarchy presented unless expressly stated otherwise.

The invention is specified by the independent claims. Preferred embodiments are defined in the dependent claims. In the following description, although numerous features may be designated as optional, it is nevertheless acknowledged that all features comprised in the independent claims are not to be read as optional.

The above and other aspects and their implementations are described in greater detail in the drawings, the descriptions, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic diagram of a network according to an embodiment of the present disclosure;

FIG. 2 shows a schematic diagram of a QoS model in the 5GS according to an embodiment of the present disclosure;

FIG. 3 shows a schematic diagram of a wireless side data plane protocol stack according to an embodiment of the present disclosure;

FIG. 4 shows a schematic of a QoS mapping model (UL) according to an embodiment of the present disclosure;

FIG. 5 shows a schematic diagram of a PDU Session establishment procedure according to an embodiment of the present disclosure;

FIG. 6 shows a schematic diagram of a UE-requested PDU session modification procedure according to an embodiment of the present disclosure;

FIG. 7 shows a schematic diagram of a UE requested PDU Session Release procedure according to an embodiment of the present disclosure;

FIG. 8 shows a schematic diagram of a UL packet transmission procedure according to an embodiment of the present disclosure;

FIG. 9 shows a schematic diagram of a UL packet transmission procedure according to an embodiment of the present disclosure;

FIG. 10 shows an example of a schematic diagram of a wireless terminal according to an embodiment of the present disclosure;

FIG. 11 shows an example of a schematic diagram of a wireless network node according to an embodiment of the present disclosure;

FIG. 12 shows a flowchart of a method according to an embodiment of the present disclosure;

FIG. 13 shows a flowchart of a method according to an embodiment of the present disclosure.

DETAILED DESCRIPTION

In the present disclosure, the term “info” or “Info” may refer to information.

In the present disclosure, the term “Ack” or “ACK” may refer to acknowledgement (message) .

FIG. 1 shows a schematic diagram of a network (architecture) according to an embodiment of the present disclosure. In FIG. 1, the network comprises the following network functions/entities:

1) UE: User Equipment

2) RAN: Radio Access Network

In the present disclosure, the RAN manages the radio resource, delivers user data received over an N3 interface to the UE and delivers user data from the UE over the N3 interface. The RAN performs mapping between DRBs (Dedicated Radio Bearers) and the QoS (Quality-of-Service) flows in a PDU session.

In the present disclosure, the RAN may be equal to AN or RAN node.

3) AMF: Access and Mobility Management Function

The AMF includes the following functionalities: Registration Management, Connection Management, Reachability Management and Mobility Management. The AMF also performs access authentication and access authorization. The AMF is a NAS (non-access stratum) security termination and relays the SM (session management) NAS between the UE and the SMF, …, etc.

4) SMF: Session Management Function

The SMF includes the following functionalities: session establishment, modification and release, UE IP (internet protocol) address allocation &management (including optional authorization functions) , selection and control of UP (User Plane) function, downlink data notification. The SMF controls the UPF via an N4 association. The SMF provides PDR (s) (Packet Detection Rule (s) ) to the UPF to instruct how to detect user data traffic, FAR (Forwarding Action Rule) , QER (QoS Enforcement Rule) , URR (Usage Reporting Rule) to instruct the UPF how to perform the user data traffic forwarding, QoS handling and usage reporting for the user data traffic detected by using the PDR.

5) UPF: User Plane Function

The UPF includes the following functionalities: serving as an anchor point for intra-/inter-radio access technology (RAT) mobility and the external session point of interconnect to Data Network, packet routing &forwarding as indicated by SMF, traffic usage reporting, quality of service (QoS) handling for the UP, downlink packet buffering and downlink data notification triggering, …, etc. In addition, a GTP-U (GPRS UP) tunnel is used over an N3 interface between the RAN and UPF. The GTP-U tunnel is per PDU session. For downlink traffic, the UPF binds the downlink traffic to QoS flows within the GTP-U tunnel of the PDU session by using the FARs received from the SMF. For uplink traffic, the RAN transfers the user plane traffic to QoS flows identified by the UE.

6) PCF: Policy Control Function

The PCF provides QoS policy rules to control plane functions, to enforce the rules. The PCF (s) transform (s) the AF requests into PCC rules that apply to the PDU Sessions.

7) UDM: Unified Data Management

The UDM performs the generation of the 3GPP AKA Authentication Credential, access authorization based on subscription data, Serving NF Registration Management of the UE (e.g. storing serving AMF for UE, storing serving SMF for UE's PDU Session) and Subscription management, …, etc. The UDM accesses the UDR to retrieve UE subscription data and stores the UE context into the UDR. The UDM and the UDR may be deployed together.

In an embodiment, a 5GC (5G core) supports PDU Connectivity Service, i.e. a service that provides exchanges of PDUs between a UE and a data network identified by a DNN (data network name) . The PDU Connectivity Service is supported via the PDU Session. The PDU Session is an association between the UE and the Data Network that provides the PDU connectivity service.

In an embodiment, a 5G QoS model is based on QoS Flows. The 5G QoS model supports both QoS Flows that require guaranteed flow bit rate (i.e., GBR QoS Flows) and QoS Flows that do not require guaranteed flow bit rate (i.e., Non-GBR QoS Flows) . The QoS Flow is the finest granularity for QoS forwarding treatment in the 5GS. All traffic mapped to the same 5G QoS Flow receives the same forwarding treatment (e.g., scheduling policy, queue management policy, rate shaping policy, RLC (radio link control) configuration, etc. ) . That is, in this embodiment, providing different QoS forwarding treatments requires separate 5G QoS Flows.

In an embodiment, the DRBs are logical channels between the (R) AN and the UE and are in charge of QoS flow (s) transportation. The DRBs enables widely used 5G services such as eMBB (enhanced Mobile Broadband) , URLLC (Ultra Reliable Low Latency Communications) and mMTC (massive Machine Type Communications) . FIG. 2 shows a schematic diagram of a QoS model in the 5GS according to an embodiment of the present disclosure. FIG. 2 illustrates a relationship between the DRBs and the PDU session model in the 5GS. Specifically, in FIG. 2, there are 3 QoS flows belonging to the same PDU session (i.e., PDU Session A) . These 3 QoS flows are mapped into 2 DRBs (i.e., DRB#1 and DRB#2) for data transportations between the UE and the (R) AN.

In an embodiment, a SDAP (Service Data Adaptation Protocol) sublayer is used between the UE and the RAN. The main functions of the SDAP sublayer comprises mapping between the QoS flow (s) and the DRBs and marking QoS flow ID (QFI) in both DL (downlink) and UL (uplink) packet transportations. FIG. 3 shows a schematic diagram of a wireless side data plane protocol stack according to an embodiment of the present disclosure. In FIG. 3, a single protocol entity of SDAP is configured for each individual PDU session. As shown in FIG. 3, the SDAP layer is on the top of the wireless side data plane protocol stack.

In an embodiment, one DRB may not be shared by the QoS flow (s) of different PDU sessions, resulting in inefficient usage of the wireless resources at the air interface between the UE and the RAN. The present disclosure provides a data transportation method allowing one DRB to be shared by the QoS flows of different PDU Sessions.

In an embodiment, the QoS flows from different PDU sessions may be mapped into the same DRB for the UL and/or DL packets transportation. That is one DRB can be shared by the QoS flows in different PDU sessions. In an embodiment, the QoS flows from different PDU sessions may be mapped into the same DRB or single DRB can be shared by the QoS flows in different PDU sessions if these QoS flows have the same QoS characteristics (e.g., resource type, PDB (Packet Delay Budget) , PER (Packet Error Rate) , etc. ) .

FIG. 4 shows a schematic of a QoS mapping model (UL) according to an embodiment of the present disclosure. In FIG. 4, the second QoS flow (i.e., the QoS flow with the QFI = 2) in a PDU session A and the third QoS flow (i.e., the QoS flow with QFI = 3) in a PDU session B share one common DRB#2 for UL and/or DL packets transportation between the UE and the RAN.

In an embodiment for the UL data transmissions, the UE maps uplink service data flow (s) into the QoS flow (s) of the PDU Session based on QoS rules provided by the network and provides corresponding QFI (s) and PDU Session ID to an AS (access stratum) layer in the UE. The AS layer in the UE determines DRB (s) used to carry the uplink data. The UE encapsulates the QFI (s) and the PDU Session ID in the SDAP (sub-) layer and sends the uplink data to the RAN. The RAN then determines the N3 Tunnel based on the encapsulated PDU Session ID and forwards the uplink data over the determined N3 Tunnel towards the UPF.

In an embodiment for DL data transmissions, the UPF maps the downlink service data flow (s) into the QoS flow (s) of the PDU Session based on packet detection rules provided by the SMF and sends the downlink data to the RAN over the N3 tunnel of the PDU Session. The RAN encapsulates the QFI and the PDU Session ID in the SDAP (sub-) layer and sends the downlink data to the UE. The UE then sends the downlink data towards the applications associated with the PDU Session.

In this disclosure, single SDAP (entity) is configured for the UE. When the RAN determines that the DRB is shared by the QoS flows from different PDU Sessions, the RAN provides the PDU Session ID and the QFI in DRB mapping rule (s) to the UE via RRC signaling (s) .

In an embodiment, when/if the RAN determines that a new QoS flow is mapped into an existing DRB, the RAN modifies MBR (maximum bit rate) of the DRB, to accommodate traffic of this new QoS flow. In an embodiment, the QoS flow may be non GBR QoS flow. In an embodiment, the GBR QoS Flow may not be mapped into the existing DRB because the bit rate of the GBR QoS flow may not be guaranteed flow bit rate. In an embodiment, for all traffic of this new QoS flow shares the same QoS characteristics (i.e., same type of resource type) of the DRB.

In an embodiment, reflective QoS function enables the UE to map UL User Plane traffic to QoS Flows. This is achieved by creating UE-derived QoS rules by the UE based on the received DL traffic. For a UE supporting the Reflective QoS function, the UE creates UE-derived QoS rule (s) for the uplink traffic based on the received DL traffic if the Reflective QoS function is used for some traffic flows. The UE may use the UE-derived QoS rule (s) to determine the mapping of the UL traffic to the QoS Flows. In an embodiment, the UE receives the PDU Session ID in the SDAP (sub-) layer and determines the UE-derived QoS rule for the PDU Session identified by the PDU Session ID. In an embodiment, the UE-derived QoS rule contains/comprises at least one UL Packet Filter, the QFI and a Precedence value.

PDU session establishment

FIG. 5 shows a schematic diagram of a PDU Session establishment procedure according to an embodiment of the present disclosure. Specifically, the PDU Session establishment procedure shown in FIG. 5 comprises the following steps:

Step 501: The UE sends a PDU session Establishment request in the form of NAS message to the AMF with the following information: request S-NSSAI (s) , DNN, PDU Session ID, Request type, and N1 SM container.

Step 502: The AMF selects the SMF for the PDU Session via the NRF or local configuration. In the case of via NRF, the AMF provides the DNN and S-NSSAI to the NRF. Based on the parameters received, the NRF selects an SMF for the AMF and sends back the Service Area of the selected SMF.

Step 503: The AMF sends a Create SM Context Request to the selected SMF, together with PDU Session ID, UE location info, Access Type, RAT Type, Operation Type and other information.

Step 504: The SMF sends a response of creating SM context to the AMF with SM context ID, in response to the SM context creating request in step 503.

Step 505. The SMF determines that the PCC authorization is required and requests to establish an SM Policy Association with the PCF by invoking a ‘Npcf_SMPolicyControl_Create’ operation.

Step 506: The PCF makes an authorization and policy decision. After that, the PCF answers the request in step 505 via a ‘Npcf_SMPolicyControl_Create’ response. In this response, the PCF may provide PCC rules to the SMF. The SMF selects an appropriate UPF and requests the UPF to allocate an N3 tunnel for the uplink data transportation.

Step 507: The SMF sends a ‘Namf_Communication_N1N2MessageTransfer’ message to the AMF. This message contains items such as PDU Session ID, N2 SM information (PDU Session ID, QFI (s) , QoS Profile (s) , N3 tunnel of the UPF) and N1 SM container (PDU Session Establishment Accept) .

Step 508: The AMF receives the ‘N1N2MessageTransfer’ request from the SMF and . Then, the AMF sends a PDU session request and forwards the following items to the (R) AN: N2 PDU Session Request (N2 SM information, NAS message (PDU Session ID, N1 SM container (PDU Session Establishment Accept) ) ) .

Step 509: The (R) AN may issue AN-specific signaling exchange with the UE, which is related to the information received from the SMF. For example, in the case of an NG-RAN, an RRC reconfiguration may take place with the UE establishing the necessary NG-RAN resources related to the QoS profile (s) . If the (R) AN decides that the QoS flows of this PDU session can be mapped into the existing DRB, the (R) AN adjusts the MBR (maximum bit rate) of the DRB to ensure that the total bit rate of all QoS flows mapped onto the DRB does not exceed the MBR of the DRB. After that, the RAN sends the updated DRB mapping rule (s) to the UE via RRC reconfiguration procedure (s) . The RAN may also send the NAS message (PDU Session ID, N1 SM container (PDU Session Establishment Accept) ) to the UE.

Step 510: The (R) AN also allocates (R) AN Tunnel Info for the PDU Session and returns an N2 PDU Session response to the AMF, together with PDU session ID, AN tunnel information and a list of accepted and rejected QFIs.

Step 511: After receiving the N2 PDU session response from the RAN in step 510, the AMF decides to update the SM context of the user. To do so, the AMF sends an updating request and forwards the N2 SM information containing/comprising SM Context ID, N2 SM information and Request Type, etc. to the SMF. The SMF receives the updating request from the AMF and may return an updating successful response. On the other hand, the SMF may subscribe a UE mobility notification from the AMF, which may include information such as location information of the UE and whether the UE presents in the area of interest or not.

PDU session modification

FIG. 6 shows a schematic diagram of a UE-requested PDU session modification procedure according to an embodiment of the present disclosure. Specifically, the PDU session modification procedure shown in FIG. 6 comprises the following steps:

Step 601: The UE initiates the PDU Session Modification procedure by transmitting a NAS message (N1 SM container (PDU Session Modification Request (PDU session ID, Packet Filters, Operation, Requested QoS, Segregation) ) and/or PDU Session ID message.

Step 602: If the UE requests specific QoS handling for selected SDF (s) (service data flow (s) ) , the PDU Session Modification Request is sent to the SMF, together with Packet Filters describing the SDF (s) , the requested Packet Filter Operation on the indicated Packet Filters, the requested QoS.

The SMF receives the request and responds to the AMF through ‘Nsmf_PDUSession_UpdateSMContext’ . The following items are included in the response message ( [N2 SM information (PDU Session ID, QFI (s) , QoS Profile (s) , [Alternative QoS Profile (s) ] , Session-AMBR] , [CN Tunnel Info (s) ] ) , N1 SM container (PDU Session Modification Command (PDU Session ID, QoS rule (s) , QoS rule operation, QoS Flow level QoS parameters if needed for the QoS Flow (s) associated with the QoS rule (s) , Session-AMBR) ) ) .

Step 603: The AMF may send an N2 message ( [N2 SM information received from SMF] , NAS message (PDU Session ID, N1 SM container (PDU Session Modification Command) ) ) to the (R) AN.

Step 604: The (R) AN may issue AN specific signaling exchange with the UE that is related to the information received from the SMF. For example, in the case of an NG-RAN, an RRC Connection Reconfiguration may take place with the UE modifying the necessary (R) AN resources related to the PDU Session. As an alternative, if only the N1 SM container is received from the AMF in step 603, the (R) AN transports only the N1 SM container to the UE.

If the (R) AN decides that the QoS flows of this PDU session can be mapped into an existing DRB, the (R) AN adjusts the MBR of the DRB, to ensure that the total bit rate of all QoS flows mapped onto this DRB does not exceed the MBR of the DRB. The RAN sends the updated DRB mapping rule to UE via an RRC reconfiguration procedure. The RAN also sends the NAS message (PDU Session ID, N1 SM container (PDU Session Modification Accept) ) to the UE.

Step 605: The (R) AN may acknowledge the N2 PDU Session Request by sending an N2 PDU Session Ack (N2 SM information (List of accepted/rejected QFI (s) , AN Tunnel Info, PDU Session ID, Secondary RAT usage data) , User location Information) Message to the AMF.

Step 606: The AMF forwards the N2 SM information and the User location Information received from the (R) AN to the SMF via the 'Nsmf_PDUSession_UpdateSMContext’ service operation. The SMF replies to the AMF via a ‘Nsmf_PDUSession_UpdateSMContext’ Response.

Step 607: The SMF may update the N4 session of UPF (s) that are involved by the PDU Session Modification by sending an N4 Session Modification Request message to the UPF. The UPF returns an N4 Session Modification/Establishment Response message to the SMF with updated information, if available.

Step 608: The UE acknowledges the PDU Session Modification Command by sending a NAS message (PDU Session ID, N1 SM container (PDU Session Modification Command Acknowledgement) ) message to the (R) AN.

PDU Session Release

FIG. 7 shows a schematic diagram of a UE requested PDU Session Release procedure according to an embodiment of the present disclosure. The PDU Session Release procedure may be used for non-roaming and roaming with LBO (local breakout) . Specifically, the PDU Session Release procedure shown in FIG. 7 comprises the following steps:

Step 701: The UE initiates the UE Requested PDU Session Release procedure by the transmission of an NAS message (N1 SM container (PDU Session Release Request (PDU session ID) ) , PDU Session ID) . The NAS message is forwarded by the (R) AN to the AMF with an indication of User Location Information.

Step 702: The AMF invokes the ‘Nsmf_PDUSession_UpdateSMContext’ service operation and provides the N1 SM container to the SMF together with the User Location Information (ULI) received from the (R)AN.

Step 703: The SMF releases the IP address /Prefix (es) that were allocated to the PDU Session and releases the corresponding User Plane resources:

a.The SMF sends an N4 Session Release Request (N4 Session ID) message to the UPF (s) of the PDU Session. The UPF (s) drops any remaining packets of the PDU Session and releases all tunnel resources and contexts associated with the N4 Session.

b.The UPF (s) acknowledges the N4 Session Release Request by transmitting an N4 Session Release Response (N4 Session ID, [Small Data Rate Control Status] , [APN Rate Control Status] ) message to the SMF.

Step 704: The SMF responds to the AMF via the ‘Nsmf_PDUSession_UpdateSMContext’ response (N2 SM Resource Release request, N1 SM container (PDU Session Release Command) ) . Note that N2 SM Resource Release request is included.

Step 705: If the UE is in a CM-CONNECTED state and the received message from the SMF in step 704 includes an N2 SM Resource Release request, the AMF transfers the SM information received from the SMF (N2 SM Resource Release request, N1 SM container) to the (R) AN.

Step 706: When/if the (R) AN receives an N2 SM request to release the AN resources associated with the PDU Session, the (R) AN issues AN-specific signaling exchange (s) with the UE, to release the corresponding AN resources.

In the case of the (R) AN being an NG-RAN, the NAS message is sent to the UE in an RRC message which may take place with the UE releasing the NG-RAN resources related to the PDU Session. If the NG-RAN resources (e.g., DRB) are shared by the QoS flows of other existing PDU Session (s) , the NG-RAN does not release the NG-RAN resources, adjusts the MBR (maximum bit rate) of the DRB to ensure that the total bit rate of all QoS flows mapped onto the DRB does not exceed the MBR of the DRB, and sends the updated DRB mapping rule to the UE via RRC reconfiguration procedure.

Step 707: The (R) AN acknowledges the N2 SM Resource Release Request by sending an N2 SM Resource Release Acknowledgement Message to the AMF with User Location Information and Secondary RAT usage data.

Step 708: The AMF invokes the ‘Nsmf_PDUSession_UpdateSMContext’ (N2 SM Resource Release Ack (Secondary RAT usage data) , User Location Information) to the SMF. The SMF responds to the AMF with a ‘Nsmf_PDUSession_UpdateSMContext’ response.

Step 709: The UE acknowledges the PDU Session Release Command by sending a NAS message (PDU Session ID, N1 SM container (PDU Session Release Ack) ) to the (R) AN.

FIG. 8 shows a schematic diagram of a UL packet transmission procedure according to an embodiment of the present disclosure. At the start of the whole procedure illustrates in FIG. 8, the PDU session and DRB (s) are established using a PDU session establishment procedure (e.g., the procedure described in FIG. 5) (step 800) . Next, UL service data flow (s) is to be transmitted from the UE to the UPF (step 801) . For the UL data transmission, the UE in step 802 maps uplink service data flow (s) into QoS flow (s) of PDU Session (s) based on the QoS rules provided by the network and provides the QFI (s) as well as the PDU Session ID (s) to the AS layer in the UE. In step 803, the AS layer in the UE determines the DRB (s) used to carry the uplink data based on the DRB mapping rule (s) provided by the RAN. In step 804, the UE encapsulates the QFI (s) and the PDU Session ID (s) in the SDAP (sub-) layer and sends the uplink data to the RAN over the air interface. In step 805, the RAN determines the corresponding N3 Tunnel (s) based on the PDU Session ID (s) and forwards the uplink data over the determined N3 Tunnel (s) towards the UPF.

FIG. 9 shows a schematic diagram of a UL packet transmission procedure according to an embodiment of the present disclosure. At the start of the whole procedure illustrates in FIG. 9, the PDU session and DRB (s) are established using a PDU session establishment procedure (e.g., the procedure described in FIG. 5) (step 900) . Then, DL service data flow (s) /packet (s) is to be transmitted from the UPF to the (step 901) . For the DL data transmissions, the UPF in step 902 maps downlink service data flow (s) into QoS flow (s) of a PDU Session based on the packet detection rules provided by the SMF and in step 903 sends the downlink data to the RAN over the corresponding N3 tunnel (s) of the PDU Session. In step 904, the RAN determines the DRB (s) for carrying the downlink data based on the DRB mapping rule (s) . In step 905, the RAN encapsulates the QFI (s) and the PDU Session ID in the SDAP (sub-) layer and sends the downlink data to the UE. The UE sends the downlink data towards the applications associated with the PDU Session.

In an embodiment, the RAN may perform at least one of:

- receiving QoS profiles of a QoS flow from SMF,

- determining the QoS flow is mapped into new DRB or an existing DRB of other PDU Session, or

- sending the new DRB mapping rule to the UE, wherein the DRB mapping rule indicates the QoS flow of this PDU Session is mapped onto a new DRB or an existing DRB.

In an embodiment, the RAN may further perform at least one of:

- receiving the uplink data from UE, together with the PDU Session ID and QFI,

- determining the N3 tunnel of the PDU session based on the received PDU session ID, or

- forwarding the uplink data towards the UPF via the PDU session.

As an alternative or in addition, the RAN may further perform at least one of:

- receiving the downlink data from the UPF over the N3 tunnel of the PDU session,

- determining the DRB based on the DRB mapping rule, or

- forwarding the downlink data toward the UE, together with the PDU Session ID and the QFI.

In an embodiment, the UE may perform at least one of:

- receiving QoS rules from the SMF,

- receiving DRB mapping rules from the RAN, wherein the DRB mapping rule indicates the QoS flow of this PDU Session is mapped onto a new DRB or an existing DRB,

- receiving uplink data from the application,

- determining the QoS flows configured to carry the uplink data based on the QoS rules received from the SMF,

- determining the DRB configured to carry the uplink data based on the DRB mapping rules received from the RAN,

- forwarding the uplink data together with the PDU Session ID and the QFI.

FIG. 10 relates to a schematic diagram of a wireless terminal 100 according to an embodiment of the present disclosure. The wireless terminal 100 may be a user equipment (UE) , a mobile phone, a laptop, a tablet computer, an electronic book or a portable computer system and is not limited herein. The wireless terminal 100 may include a processor 1000 such as a microprocessor or Application Specific Integrated Circuit (ASIC) , a storage unit 1010 and a communication unit 1020. The storage unit 1010 may be any data storage device that stores a program code 1012, which is accessed and executed by the processor 1000. Embodiments of the storage unit 1010 include but are not limited to a subscriber identity module (SIM) , read-only memory (ROM) , flash memory, random-access memory (RAM) , hard-disk, and optical data storage device. The communication unit 1020 may a transceiver and is used to transmit and receive signals (e.g., messages or packets) according to processing results of the processor 1000. In an embodiment, the communication unit 1020 transmits and receives the signals via at least one antenna 1022 shown in FIG. 10.

In an embodiment, the storage unit 1010 and the program code 1012 may be omitted and the processor 1000 may include a storage unit with stored program code.

The processor 1000 may implement any one of the steps in exemplified embodiments on the wireless terminal 100, e.g., by executing the program code 1012.

The communication unit 1020 may be a transceiver. The communication unit 1020 may as an alternative or in addition be combining a transmitting unit and a receiving unit configured to transmit and to receive, respectively, signals to and from a wireless network node (e.g., a base station) .

FIG. 11 relates to a schematic diagram of a wireless network node 110 according to an embodiment of the present disclosure. The wireless network node 110 may be a satellite, a base station (BS) , a network entity, a Mobility Management Entity (MME) , Serving Gateway (S-GW) , Packet Data Network (PDN) Gateway (P-GW) , a radio access network (RAN) node, a next generation RAN (NG-RAN) node, a gNB, an eNB, a gNB central unit (gNB-CU) , a gNB distributed unit (gNB-DU) a data network, a core network or a Radio Network Controller (RNC) , and is not limited herein. In addition, the wireless network node 110 may comprise (perform) at least one network function such as an access and mobility management function (AMF) , a session management function (SMF) , a user place function (UPF) , a policy control function (PCF) , an application function (AF) , etc. The wireless network node 110 may include a processor 1100 such as a microprocessor or ASIC, a storage unit 1110 and a communication unit 1120. The storage unit 1110 may be any data storage device that stores a program code 1112, which is accessed and executed by the processor 1100. Examples of the storage unit 1110 include but are not limited to a SIM, ROM, flash memory, RAM, hard-disk, and optical data storage device. The communication unit 1120 may be a transceiver and is used to transmit and receive signals (e.g., messages or packets) according to processing results of the processor 1100. In an example, the communication unit 1120 transmits and receives the signals via at least one antenna 1122 shown in FIG. 11.

In an embodiment, the storage unit 1110 and the program code 1112 may be omitted. The processor 1100 may include a storage unit with stored program code.

The processor 1100 may implement any steps described in exemplified embodiments on the wireless network node 110, e.g., via executing the program code 1112.

The communication unit 1120 may be a transceiver. The communication unit 1120 may as an alternative or in addition be combining a transmitting unit and a receiving unit configured to transmit and to receive, respectively, signals to and from a wireless terminal (e.g., a user equipment or another wireless network node) .

FIG. 12 shows a flowchart of a method according to an embodiment of the present disclosure. The method shown in FIG. 12 may be used in a wireless network node (e.g., (R) AN (node) or gNB) and comprises the following step:

Step 1201: Transmit, to a wireless terminal, DRB mapping rule (s) indicating that a first QoS flow of a first PDU session is mapped to a common DRB to which a second QoS flow of a second PDU session is mapped.

In FIG. 12, QoS flows of different PDU sessions may share the same DRB. For example, the wireless network node may map a first QoS flow of a first PDU session to a common DRB to which a second QoS flow of a second PDU session is mapped and transmits DRB mapping rule (s) indicating such mapping to a wireless terminal (e.g., UE) associated with the first PDU session.

In an embodiment, the wireless network node may modify/adjust an MBR of the common DRB based on the first QoS flow of the first PDU session, e.g., to ensure that the total bit rate of all QoS flows mapped onto the common DRB does not exceed the MBR of the DRB.

In an embodiment, the first QoS flow and/or the second QoS flow is a non-GBR QoS flow.

In an embodiment, the wireless network node receives uplink data on the common DRB from the wireless terminal. In this embodiment, the uplink data is received with the corresponding PDU session ID and the corresponding QFI. Based on the received PDU session ID, the wireless network node is able to determine a N3 tunnel and transmits the uplink data on the determined N3 tunnel to a UPF.

In an embodiment, the wireless network node receives downlink data configured to be transmitted on the common DRB. For example, the downlink data may belong to the first QoS flow or the second QoS flow. In this embodiment, the wireless network node transmits the downlink data on the common DRB to the wireless terminal together with the corresponding PDU session ID and the corresponding QFI.

In an embodiment, the PDU session ID and the QFI which is transmitted/received with the data are encapsulated in the SDAP (sub-) layer. For example, the PDU session ID and the QFI may be comprised in the SDAP header of the data.

FIG. 13 shows a flowchart of a method according to an embodiment of the present disclosure. The method shown in FIG. 13 may be used in a wireless terminal (e.g., UE) and comprises the following step:

Step 1301: Receive, from a wireless network node, DRB mapping rule (s) indicating that a first QoS flow of a first PDU session is mapped to a common DRB to which a second QoS flow of a second PDU session is mapped.

In this embodiment, one DRB may be shared by QoS flows of different PDU sessions. For example, the wireless terminal may receive, from a wireless network node, DRB mapping rule (s) indicating that a first QoS flow of a first PDU session is mapped to a common DRB to which a second QoS flow of a second PDU session is mapped.

In an embodiment, an MBR of the common DRB may be adjusted/modified based on the first QoS flow (after the first QoS flow is mapped to the common DRB) .

In an embodiment, if/when transmitting uplink data (on the common DRB) to the wireless network node, the wireless terminal transmits the uplink data together with the corresponding PDU session ID and QFI, to indicate the PDU session associated with the uplink data.

In an embodiment, the wireless terminal receives downlink data (on the common DRB) from the wireless network node together with the corresponding PDU session ID and QFI. The wireless terminal therefore can determine the PDU session associated with the downlink data. In this embodiment, the wireless terminal may further determine QoS rule (s) for the corresponding PDU session based on the received downlink data.

While various embodiments of the present disclosure have been described above, it should be understood that they have been presented by way of example only, and not by way of limitation. Likewise, the various diagrams may depict an example architectural or configuration, which are provided to enable persons of ordinary skill in the art to understand exemplary features and functions of the present disclosure. Such persons would understand, however, that the present disclosure is not restricted to the illustrated example architectures or configurations but can be implemented using a variety of alternative architectures and configurations. Additionally, as would be understood by persons of ordinary skill in the art, one or more features of one embodiment can be combined with one or more features of another embodiment described herein. Thus, the breadth and scope of the present disclosure should not be limited by any one of the above-described exemplary embodiments.

It is also understood that any reference to an element herein using a designation such as "first, " "second, " and so forth does not generally limit the quantity or order of those elements. Rather, these designations can be used herein as a convenient means of distinguishing between two or more elements or instances of an element. Thus, a reference to first and second elements does not mean that only two elements can be employed, or that the first element must precede the second element in some manner.

Additionally, a person having ordinary skill in the art would understand that information and signals can be represented using any one of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits and symbols, for example, which may be referenced in the above description can be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

A skilled person would further appreciate that any one of the various illustrative logical blocks, units, processors, means, circuits, methods and functions described in connection with the aspects disclosed herein can be implemented by electronic hardware (e.g., a digital implementation, an analog implementation, or a combination of the two) , firmware, various forms of program or design code incorporating instructions (which can be referred to herein, for convenience, as "software" or a "software unit” ) , or any combination of these techniques.

To clearly illustrate this interchangeability of hardware, firmware and software, various illustrative components, blocks, units, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware, firmware or software, or a combination of these techniques, depends upon the particular application and design constraints imposed on the overall system. Skilled artisans can implement the described functionality in various ways for each particular application, but such implementation decisions do not cause a departure from the scope of the present disclosure. In accordance with various embodiments, a processor, device, component, circuit, structure, machine, unit, etc. can be configured to perform one or more of the functions described herein. The term “configured to” or “configured for” as used herein with respect to a specified operation or function refers to a processor, device, component, circuit, structure, machine, unit, etc. that is physically constructed, programmed and/or arranged to perform the specified operation or function.

Furthermore, a skilled person would understand that various illustrative logical blocks, units, devices, components and circuits described herein can be implemented within or performed by an integrated circuit (IC) that can include a general purpose processor, a digital signal processor (DSP) , an application specific integrated circuit (ASIC) , a field programmable gate array (FPGA) or other programmable logic device, or any combination thereof. The logical blocks, units, and circuits can further include antennas and/or transceivers to communicate with various components within the network or within the device. A general purpose processor can be a microprocessor, but in the alternative, the processor can be any conventional processor, controller, or state machine. A processor can also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other suitable configuration to perform the functions described herein. If implemented in software, the functions can be stored as one or more instructions or code on a computer-readable medium. Thus, the steps of a method or algorithm disclosed herein can be implemented as software stored on a computer- readable medium.

Computer-readable media includes both computer storage media and communication media including any medium that can be enabled to transfer a computer program or code from one place to another. A storage media can be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer.

In this document, the term "unit" as used herein, refers to software, firmware, hardware, and any combination of these elements for performing the associated functions described herein. Additionally, for purpose of discussion, the various units are described as discrete units; however, as would be apparent to one of ordinary skill in the art, two or more units may be combined to form a single unit that performs the associated functions according to embodiments of the present disclosure.

Additionally, memory or other storage, as well as communication components, may be employed in embodiments of the present disclosure. It will be appreciated that, for clarity purposes, the above description has described embodiments of the present disclosure with reference to different functional units and processors. However, it will be apparent that any suitable distribution of functionality between different functional units, processing logic elements or domains may be used without detracting from the present disclosure. For example, functionality illustrated to be performed by separate processing logic elements, or controllers, may be performed by the same processing logic element, or controller. Hence, references to specific functional units are only references to a suitable means for providing the described functionality, rather than indicative of a strict logical or physical structure or organization.

Various modifications to the implementations described in this disclosure will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other implementations without departing from the scope of the claims. Thus, the disclosure is not intended to be limited to the implementations shown herein, but is to be accorded the widest scope consistent with the novel features and principles disclosed herein, as recited in the claims below.

Claims

A wireless communication method for use in a wireless network node, the method comprising:

transmitting, to a wireless terminal, a data radio bearer (DRB) mapping rule indicating that a first quality-of-service (QoS) flow of a first protocol data unit (PDU) session is mapped to a common DRB to which a second QoS flow of a second PDU session is mapped.
The wireless communication method of claim 1, further comprising:

modifying a maximum bit rate (MBR) of the common DRB based on the first QoS flow of the first PDU session.
The wireless communication method of claim 1 or 2, wherein the first QoS flow of the first PDU session is a non-guaranteed-bit-rate QoS flow.
The wireless communication method of any of claims 1 to 3, further comprising:

receiving, from the wireless terminal, uplink data on the common DRB, a PDU session identifier of the uplink data and a QoS flow identifier (QFI) of the uplink data,

determining an N3 tunnel based on the PDU session ID of the uplink data, and

transmitting, to a user plane function, the uplink data by using the determined N3 tunnel.
The wireless communication method of any of claims 1 to 4, further comprising:

receiving, from a user plane function, downlink data configured to be transmitted via the common DRB, and

transmitting, to the wireless terminal, the downlink data on the common DRB, a PDU session identifier of the downlink data and a QoS flow identifier (QFI) of the downlink data.
The wireless communication method of claim 4 or 5, wherein the PDU session identifier and the QFI are in a Service Data Adaptation Protocol (SDAP) header.
A wireless communication method for use in a wireless network node, the method comprising:

receiving, from a wireless network node, a data radio bearer (DRB) mapping rule indicating that a first quality-of-service (QoS) flow of a first protocol data unit (PDU) session is mapped to a common DRB to which a second QoS flow of a second PDU session is mapped.
The wireless communication method of claim 7, wherein a maximum bit rate (MBR) of the common DRB is modified based on the first QoS flow of the first PDU session.
The wireless communication method of claim 7 or 8, wherein the first QoS flow of the first PDU session is a non-guaranteed-bit-rate QoS flow.
The wireless communication method of any of claims 7 to 9, further comprising:

transmitting, to the wireless network node, uplink data on the common DRB, a PDU session identifier of the uplink data and a QoS flow identifier (QFI) of the uplink data.
The wireless communication method of any of claims 7 to 10, further comprising:

receiving, from the wireless network node, downlink data on the common DRB, a PDU session identifier of the downlink data and a QoS flow identifier (QFI) of the downlink data.
The wireless communication method of claim 10 or 11, wherein the PDU session identifier and the QFI are in a Service Data Adaptation Protocol (SDAP) header.
A wireless network node, comprising:

a communication unit, configured to transmit, to a wireless terminal, a data radio bearer (DRB) mapping rule indicating that a first quality-of-service (QoS) flow of a first protocol data unit (PDU) session is mapped to a common DRB to which a second QoS flow of a second PDU session is mapped.
The wireless network node of claim 13, further comprising a processor configured to perform the wireless communication method of any of claims 2 to 6.
A wireless terminal, comprising:

a communication unit, configured to receive, from a wireless network node, a data radio bearer (DRB) mapping rule indicating that a first quality-of-service (QoS) flow of a first protocol data unit (PDU) session is mapped to a common DRB to which a second QoS flow of a second PDU session is mapped.
The wireless terminal of claim 15, further comprising a processor configured to perform the wireless communication method of any of claims 8 to 12.
A computer program product comprising a computer-readable program medium code stored thereupon, the code, when executed by a processor, causing the processor to implement a wireless communication method recited in any one of claims 1 to 16.