Patent Application
20220022089
The invention relates to QoS flows in the 5G Architecture.
Generally, all terms used herein are to be interpreted according to their ordinary meaning in the relevant technical field, unless a different meaning is clearly given and/or is implied from the context in which it is used. All references to a/an/the element, apparatus, component, means, step, etc. are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. The steps of any methods disclosed herein do not have to be performed in the exact order disclosed, unless a step is explicitly described as following or preceding another step and/or where it is implicit that a step must follow or precede another step. Any feature of any of the embodiments disclosed herein may be applied to any other embodiment, wherever appropriate. Likewise, any advantage of any of the embodiments may apply to any other embodiments, and vice versa. Other objectives, features, and advantages of the enclosed embodiments will be apparent from the following description.
Fourth Generation (4G) networks are now widely deployed and the Third Generation Partnership Project (3GPP) is currently developing the standards for Fifth Generation (5G) systems. When 5G networks become available, network operators are expected to deploy a mixture of 5G core (5GC) networks and Evolved Packet Core (EPC) networks.
Currently 3GPP is finalizing specifications for 5GC network in 3GPP Technical specification, TS 23.501, 3GPP TS 23.502 and 3GPP TS 23.503. The 5GC network may be based on an evolution of the current EPC or based on a “clean slate” approach. 5GC is defined over the Network Function Virtualization (NFV) and Software Defined Networking (SDN). 5GC must support various access networks including but not limited to:
The Session Management function (SMF) as specified in 3GPp TS 23.501 includes the following functionality. Some or all of the SMF functionalities may be supported in a single instance of a SMF:
In addition to the functionalities of the SMF described above, the SMF may include policy related functionalities as described in clause 6.2.2 in 3GPP TS 23.503
3GPP 5G and 5GC introduce a different QoS framework compared to the 4G and EPC QoS framework. 5G supports a flow based QoS model, while 4G is based on bearer level QoS. 5G specifies a guaranteed bit rate (GBR) QoS flow and a non-guaranteed bit rate (Non-GBR or NGBR) QoS flow which is equivalent to 4G GBR bearer, and non-Non-GBR or NGBR bearer. In 4G and EPC, each bearer has an associated QoS Class Identifier (QCI) and an Allocation and Retention Priority (ARP) and then each QCI, i.e., each bearer, is characterized by priority, packet delay budget and acceptable packet loss rate. QoS is hence specified per bearer where a bearer may transport one or more media flows sharing the same QoS characteristics of the bearer. On the other hand, QoS in 5G is defined at the flow level where at the gNB, the Service Data Adaptation Protocol (SDAP) sublayer configured by the Radio Resource Control (RRC) sublayer, maps QoS flows to radio bearers. One or more QoS flows may be mapped onto one radio bearer. The 5G QoS Identifier (5QI) is a scalar that is used as a reference to 5G QoS characteristics to control QoS forwarding treatment for the QoS Flow (e.g. scheduling weights, admission thresholds, queue management thresholds, link layer protocol configuration, etc.). 5QI is similar to the QoS class identifier (QCI) of 4G. In addition, a QoS Flow ID (QFI) is used to identify a QoS flow in the 5G system. User Plane traffic with the same QFI within a Protocol Data Unit (PDU) session receives the same traffic forwarding treatment (e.g. scheduling, admission threshold), i.e., 5QI. The QFI is carried in an encapsulation header on N3 (Reference point between RAN and User Plane Function (UPF) in 5GC). The QFI is hence unique within a PDU session in 5G.
Within the 5G system, a QoS Flow is controlled by the SMF and may be preconfigured, or established via the PDU Session Establishment procedure (see TS 23.502, clause 4.3.2), or the PDU Session Modification procedure (see TS 23.502 clause 4.3.3.
Any QoS Flow is characterised by:
Within the 5G System, a QoS Flow associated with the default QoS rule is required to be established for a PDU Session and remains established throughout the lifetime of the PDU Session. This QoS Flow should be a Non-GBR QoS Flow and provides the UE with connectivity throughout the lifetime of the PDU Session.
3GPP TS 23.502 has defined an Access Network Release procedure which is used to release the logical NG-AP signalling connection (N2 connection) and the associated N3 User Plane connections, and (R)AN RRC signalling and resources. 3GPP TS 23.502 describes that when the AN Release procedure specified in Clause 4.2.6 of 3GPP TS 23.502, is triggered due to radio reasons, e.g., Radio connection with UE lost, the SMF shall trigger the GBR QoS flows deactivation. The following is an excerpt from clause 4.2.6 of 3GPP TS 23.502″ “If the cause of AN Release is because of User Inactivity, or UE Redirection, the SMF shall preserve the GBR QoS Flows. Otherwise, the SMF shall trigger the PDU Session Modification procedure (see clause 4.3.3) for the GBR QoS Flows of the UE after the AN Release procedure is completed.”
TS23.502 has also defined the Network Triggered Service Request procedure (see clause 4.2.3.3 of 3GPP TS 23.502, where the AMF sends Namf_Communications_N1N2MessageTransfer Failure Notification to the SMF if the UE does not respond to the paging.
Few challenges exist with the existing deactivation of the GBR QoS flows procedure. In a network where asynchronous type communication, ATC, is not deployed, when SMF triggers the PDU Session Modification procedure to deactivate the GBR QoS flows, e.g., 5QI=1 QoS flow for voice service, if the UE is not reachable, there will be misalignment of QoS rules and QoS flows status between UE and SMF, which will cause negative impact on user experience.
Two typical use cases are described below:
In both cases, the GBR QoS flows and/or non-GBR QoS Flow that is not associated to the default QoS Rule, deactivation has to be executed in network side anyway, e.g., in SMF and PCF. For IMS voice call case, the IMS domain also should treat the relevant voice service as being terminated immediately.
The existing technology lacks a way to retry the QoS flows deactivation towards UE, which results in the misalignment of QoS rules and QoS flows status between UE and SMF.
Subsequently, when the UE regains the radio connection and starts the uplink data transfer again, the data corresponding to such deactivated QoS flows either cannot be matched to radio resource or will be dropped by NG-RAN. This will have negative impact on user experience.
NOTE: according to 3GPP TS 23.502, if ATC feature is activated, AMF updates and stores the UE context based on the PDU Session Modification request. In this case, the GBR QoS flows deactivation can be notified to the UE the next time the UE enters CM Connected state. However, ATC feature probably does not apply here since, e.g., for IMS voice case, some information such as access network information is needed during the SMF triggered PDU Session Modification procedure.
To mitigate the above challenges, methods and apparatus embodiments are provided for synchronizing the status of the QoS Flows between the UE and the 5GC. The unsynchronized QoS Flow status may happen when the network initiated QoS Flow deletion cannot reach the UE e.g. due to radio link failure or UE not responding.
Without such solutions, a QoS Flow may be deleted in the 5GC but not in the UE, and the UL packets sent via such QoS Flow will get dropped by the UPF in 5GC because QFI of the QoS Flow is not recognized by the UPF.
In accordance with one aspect, when the Session Management Function, SMF, in 5GC, would like to delete a QoS Flow (which is not the “default QoS Flow”) in the UE, if there is no response from UE, e.g. due to radio link failure, or paging no response, the SMF marks that the status of those GBR QoS Flows are to be synchronized with the UE.
At Service Request, for a PDU Session that the SMF has determined to accept the activation of UP connection, the SMF also checks if there is any QoS Flow that is deleted in the 5GC but not synchronized with the UE yet. If such QoS Flows exist, the SMF includes the PDU Session Modification Command in N1 SM Container to delete those QoS Flows.
NOTE: “Default QoS Flow” refer to the QoS Flow associated with the default QoS rule
According to one aspect, for an SMF, the embodiments described provide for continuing with the GBR QoS flows deactivation towards the PCF (which then notifies the IMS domain for the IMS voice service scenario) while deferring the GBR QoS flows deactivation towards the UE in the below cases:
Deactivation by the SMF to the UE of the GBR QoS flow(s) and/or the non-GBR QoS flow(s) that is (Are) not associated with the default QoS Rule, can thus be performed later on when:
According to other aspects, for UE initiated GBR QoS flows (or non-GBR QoS flows not associated to default QoS Rule) deactivation due to radio connection problem, the solution is to defer the GBR (and/or non-GBR) QoS flows deactivation towards SMF and reinitiate it when the UE regains the radio connection. Note that the non-GBR QoS flows described herein are not associated to a default QoS Rule, else deactivation of such QoS flow would result in deactivation of the PDU session.
Beside explicitly deactivating the GBR/non-GBR QoS flows, the SMF and the UE may use a new information element to synchronize QoS rules and QoS flows status. This new information element represents the overall QoS rules and QoS flows status, i.e., for each QoS rule and QoS flow, indicates whether it is active or not.
The embodiments described herein should prevent the misalignment of QoS rules and QoS flows status between SMF and UE and avoid the negative user experience.
In one aspect, a method of operation of a network node implementing a Session Management Function, SMF, in a core network of a cellular communications system is provided. The method comprises initiating deactivation, for a Packet Data Unit, PDU, session of a User Equipment, UE, of at least one of a Guaranteed bit rate, GBR, Quality of Service, QoS, flow and a non-GBR QoS flow that is not associated to a default QoS rule and upon determining that a response to the deactivation is not received from the UE, deferring the deactivation of the at least one of the GBR QoS flow and the non-GBR QoS flow associated with the PDU session.
In one aspect, the method further comprises marking the at least one of the GBR QoS flow and the non-GBR QoS flow as pending synchronization with the UE. In another aspect, the method further comprises starting a synchronization timer for re-initiating the deactivation of the at least one of the GBR QoS flow and the non-GBR QoS flow with the UE.
In accordance with another aspect, the method further comprises subscribing by the SMF to notification of reachability for the UE at the Access Mobility Management function, AMF, in order for the SMF to determine that it can start synchronization of the QoS flows with the UE.
In accordance with another aspect, The method further comprises sending a request or a command to the UE to synchronize the at least one of the GBR QoS flow and the non-GBR QoS flow in response to receiving a request to activate the user plane, UP, connections for the UE; or to receiving a notification that the UE is reachable; or that the synchronization timer has expired.
In accordance with another aspect, the the request or the command initiated by the SMF to synchronize the GBR QoS flow and/or the non-GBR QoS flow with the UE comprise a QoS rule status and a QoS flow status indicating the GBR QoS flow and/or the non-GBR QoS Flow to synchronize or indicating the GBR QoS flow and/or non-GBR QoS Flow that are deleted in the SMF.
In accordance with another aspect, a network node implementing a Session Management Function, SMF in a core network of a cellular communications system is provided and adapted to perform any of the embodiments described herein.
In accordance with another aspect, a network node implementing a Session Management Function, SMF in a core network of a cellular communications system, comprises one or more processors; and memory comprising instructions executable by the one or more processors whereby the network node is adapted to perform any of the embodiments described herein.
In another aspect, a network node implementing a Session Management Function, SMF in a core network of a cellular communications system, comprises one or more modules operable to perform any of the embodiments described herein.
According to one aspect, a method of operation of a wireless device, having an established Packet Data Unit, PDU, Session, with a Core network and the PDU session has at least a GBR QoS Flow and/or a non-GBR QoS flow that is not associated to the default QoS rule, is provided. The method comprises UE locally deactivating the GBR QoS flow and/or the non-GBR QoS Flow that is not associated to the default QoS Rule of the Packet Data Unit, PDU, session and upon determining that the Core network is not reachable, the UE will defer synchronization of the GBR QoS flow and/or the non-GBR QoS Flow that is not associated with the default QoS Rule. Upon reconnecting with the Core Network, sending a request to the Core Network to synchronize the GBR QoS flow and/or the non-GBR QoS Flow that is not associated with the default QoS Rule.
In another aspect, determining that the Core network is not reachable is due to UE having/detecting poor radio conditions.
In another aspect, the request to synchronize the GBR QoS flow and/or the non-GBR QoS Flow consists of a NAS PDU Session Modification request message and the request may further comprise a QoS Rules status and a QoS Flow status.
In accordance with one aspect, a wireless device is adapted to perform the any of the embodiments described herein.
In accordance with another aspect, a wireless device comprises one or more processors; and memory comprising instructions executable by the one or more processors whereby the wireless is adapted to perform any of the embodiments described herein.
In accordance with another aspect, a wireless device comprises one or more modules operable to perform any of the embodiments described herein.
This summary is not an extensive overview of all contemplated embodiments and is not intended to identify key or critical aspects or features of any or all embodiments or to delineate the scope of any or all embodiments. In that sense, other aspects and features will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments in conjunction with the accompanying figures.
The accompanying drawing figures incorporated in and forming a part of this specification illustrate several aspects of the disclosure, and together with the description serves to explain the principles of the disclosure.
In the following description, numerous specific details are set forth. However, it is understood that embodiments may be practiced without these specific details. In other instances, well-known circuits, structures, and techniques have not been shown in detail in order not to obscure the understanding of the description. Those of ordinary skill in the art, with the included description, will be able to implement appropriate functionality without undue experimentation.
References in the specification to “one embodiment,” “an embodiment,” “an example embodiment,” etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to implement such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.
As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes,” and/or “including” when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
In the present disclosure, a wireless device is a non-limiting term and refers to a device capable, configured, arranged and/or operable to communicate wirelessly with network nodes and/or another wireless device. Communicating wirelessly may involve transmitting and/or receiving wireless signals using electromagnetic signals, radio waves, infrared signals, and/or other types of signals suitable for conveying information through air. In particular embodiments, wireless devices may be configured to transmit and/or receive information without direct human interaction. For instance, a wireless device may be designed to transmit information to a network on a predetermined schedule, when triggered by an internal or external event, or in response to requests from the network. Generally, a wireless device may represent any device capable of, configured for, arranged for, and/or operable for wireless communication, for example radio communication devices. Examples of wireless devices include, but are not limited to, user equipment (UE) such as smart phones. Further examples include wireless cameras, wireless-enabled tablet computers, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), USB dongles, and/or wireless customer-premises equipment (CPE).
As one specific example, a wireless device may represent a UE configured for communication in accordance with one or more communication standards promulgated by the 3rd Generation Partnership Project (3GPP), such as 3GPP's LTE, and/or 5G standards. As used herein, a “user equipment” or “UE” may not necessarily have a “user” in the sense of a human user who owns and/or operates the relevant device. Instead, a UE may represent a device that is intended for sale to, or operation by, a human user but that may not initially be associated with a specific human user.
The wireless device may support device-to-device (D2D) communication, for example by implementing a 3GPP standard for sidelink communication and may in this case be referred to as a D2D communication device.
As yet another specific example, in an Internet of Things (IOT) scenario, a wireless device may represent a machine or other device that performs monitoring and/or measurements and transmits the results of such monitoring and/or measurements to another wireless device and/or a network node. The wireless device may in this case be a machine-to-machine (M2M) device, which may in a 3GPP context be referred to as a machine-type communication (MTC) device. As one particular example, the wireless device may be a UE implementing the 3GPP narrow band internet of things (NB-IoT) standard. Particular examples of such machines or devices are sensors, metering devices such as power meters, industrial machinery, or home or personal appliances, e.g. refrigerators, televisions, personal wearables such as watches etc. In other scenarios. A wireless device such as a UE may be used as router or a relay for these internet of things devices that connect to the network via the UE. A wireless device may also represent a vehicle or other equipment that is capable of monitoring and/or reporting on its operational status or other functions associated with its operation.
A wireless device as described above may represent the endpoint of a wireless connection, in which case the device may be referred to as a wireless terminal. Furthermore, a wireless device as described above may be mobile, in which case it may also be referred to as a mobile device or a mobile terminal. The term User Equipment, UE, is used henceforth to describe the embodiments, however wireless device and user equipment may sometimes be used interchangeably.
As used herein, “network node” refers to equipment capable, configured, arranged and/or operable to communicate directly or indirectly with a wireless device and/or with other equipment in the wireless communication network, such as 5GC that enable and/or provide to the wireless device access to one or more data networks. Examples of network nodes used in the embodiments herein include, but are not limited to 5GC entities implementing session management function, SMF, policy control function, PCF, and user plane function, and an Access and an AMF. If the DN is an IMS, the AF is a P-CSCF.
More generally, network nodes may represent any suitable device (or group of devices) capable, configured, arranged, and/or operable to enable and/or provide a wireless device access to the data network over the wireless communication network (5GC) or to provide some service to a wireless device that has accessed the wireless communication network.
In context of 5GC and the present disclosure some definitions are useful:
Some of the embodiments contemplated herein will now be described more fully with reference to the accompanying drawings. Other embodiments, however, are contained within the scope of the subject matter disclosed herein, the disclosed subject matter should not be construed as limited to only the embodiments set forth herein; rather, these embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art.
The base stations 202 and the low power nodes 206 provide service to wireless devices 212-1 through 212-5 in the corresponding cells 204 and 208. The wireless devices 212-1 through 212-5 are generally referred to herein collectively as wireless devices 212 and individually as wireless device 212. The wireless devices 212 are also sometimes referred to herein as UEs.
Some properties of the NFs shown in
An NF may be implemented either as a network element on a dedicated hardware (network node), as a software instance running on a dedicated hardware, or as a virtualized function instantiated on an appropriate platform, e.g., a cloud infrastructure.
Currently there is synchronization of PDU Sessions between the UE and the 5GC at Service Request or Registration procedure, based on the PDU Session status.
However, for an active PDU session, there is no synchronization of the QoS Flows that are not associated with the default QoS rule (denoted as “dedicated QoS Flow” to simplify) within the PDU Session.
If the UE cannot be reached (e.g. due to radio connection lost) when the “dedicated QoS Flow” is deleted by the network, the QoS Flow status between the UE and the SMF will not be synchronized. As a consequence, the UE may send UL packets using the QFI of a QoS Flow that has been deleted by the network. Such packets will be sent over the default DRB as per 3GPP TS 38.300 Annex 6 (copied below)
Annex A.6 UE Initiated UL QoS Flow
0. PDU session and DRBs (including a default DRB) have been already established.
1. UE AS receives a packet with a new QFI from UE NAS.
2. UE uses the QFI of the packet to map it to a DRB. If there is no mapping of the QFI to a DRB in the AS mapping rules for this PDU session, then the packet is assigned to the default DRB.
3. UE sends the UL packet on the default DRB. The UE includes the QFI in the SDAP header.
4. gNB sends UL packets to UPF and includes the corresponding QFI.
5. If gNB wants to use a new DRB for this QoS flow, it sets up one. It can also choose to move the QoS flow to an existing DRB using RQoS or RRC signalling (see subclauses A.2 and A.3).
6. User Plane Data for the new QoS flow can then be exchanged between UE and gNB over the DRB according to the updated mapping rules and between UPF and gNB over the tunnel for the PDU session.
When such packets reach UPF, the QFI of those packets is not recognized and the packets get dropped.
Two options can mitigate the above problem, i.e., to synchronize the status of “dedicated QoS Flows” between the UE and the 5GC:
UE includes the QoS Flow Status IE (in Registration Request and Service Request) for each PDU Session if its UP connection is to be activated.
When the network decides to delete a dedicated QoS Flow, and the UE cannot be reached, the SMF mark the QoS Flow that it's to be deleted in UE.
When the SMF becomes aware that the UE is reachable (e.g. at Service Request, or Registration Request), the SMF trigger the deletion towards the UE.
For Option-1, as each PDU Session can have max 63 QoS Flows, the increased size of the NAS message due to QoS Flow status can reach N*8 bytes (N is the number of PDU Sessions to be activated), Although one may implement option 1, more detail description is provided with respect to option 2.
UE Triggered Service Request
As indicated,
The UE in CM IDLE state initiates the Service Request procedure in order to send uplink signalling messages, user data, or as a response to a network paging request. After receiving the Service Request message, the AMF may perform authentication. After the establishment of the signalling connection to an AMF, the UE or network may send signalling messages, e.g. PDU Session establishment from UE to the SMF, via the AMF.
The Service Request procedure is used by a UE in CM-CONNECTED to request activation of a User Plane connection for PDU Sessions and to respond to a NAS Notification message from the AMF.
For any Service Request, the AMF responds with a Service Accept message to synchronize PDU Session status between UE and network, if necessary. If the Service Request cannot be accepted by network, the AMF responds to UE with a Service Reject message. The Service Reject message may include an indication or a cause code instructing the UE to perform Registration Update procedure.
For this procedure, the impacted SMF and UPF, if any, are all under control of the PLMN serving the UE, e.g. in Home Routed roaming case the SMF and UPF in HPLMN are not involved.
For Service Request due to user data, network may take further actions if User Plane connection activation is not successful.
The procedure in this clause 4.2.3.2 of 3GPP TS 23.502 is applicable to the scenarios with or without intermediate UPF, and with or without intermediate UPF reselection.
1. UE to (R)AN: AN message (AN parameters, Service Request (List Of PDU Sessions To Be Activated, List Of Allowed PDU Sessions, security parameters, PDU Session status, 5G-S-TMSI)).
The List Of PDU Sessions To Be Activated is provided by UE when the UE wants to re-activate the PDU Session(s). The List Of Allowed PDU Sessions is provided by the UE when the Service Request is a response of a Paging or a NAS Notification for a PDU Session associated with non-3GPP access, and identifies the PDU Sessions that can be transferred to 3GPP access.
In case of NG-RAN:
If the procedure was triggered in response to paging or NAS notification indicating non-3GPP access, and the PDU Session for which the UE was paged or notified is in the List Of Allowed PDU Sessions provided by the UE, and the AMF received N2 SM Information only or N1 SM Container and N2 SM Information from the SMF in step 3a of clause 4.2.3.3 of 3GPP TS 23.502, the AMF notifies the SMF that the access type of the PDU session can be changed. The AMF discards any already received N1 SM Container and N2 SM Information.
The AMF may receive a Service Request to establish another NAS signalling connection via a NG-RAN while it has maintained an old NAS signalling connection for UE still via NG-RAN. In this case, AMF shall trigger the AN release procedure toward the old NG-RAN to release the old NAS signalling connection as defined in clause 4.2.6 of 3GPP TS 23.502 with following logic:
In any case of the two cases above the SMF answers to the AMF (step10) with an appropriate reject cause and the User Plane Activation of PDU Session is stopped.
Otherwise, based on the location info received from the AMF, the SMF checks the UPF Selection Criteria according to clause 6.3.3 of 3GPP TS 23.501, and determines to perform one of the following:
If the SMF selects a new UPF to act as intermediate UPF for the PDU Session, the SMF sends N4 Session Modification Request message to PDU Session Anchor UPF, providing DL Tunnel Info from new intermediate UPF. The SMF may also provide updated UL CN Tunnel Information. If the new intermediate UPF was added for the PDU Session, the UPF (PSA) begins to send the DL data to the new I-UPF as indicated in the DL Tunnel Info.
If the Service Request is triggered by the network, and the SMF removes the old I-UPF but does not replace it with a new I-UPF, and if UPF allocates UP tunnel endpoint information, the SMF may also include a request for the UPF to allocate a second tunnel endpoint for buffered DL data from the old I-UPF. In this case, the UPF (PSA) begins to buffer the DL data it may receive at the same time from the N6 interface.
7b. The UPF (PSA) sends N4 Session Modification Response message to SMF.
If requested by SMF, the UPF (PSA) sends CN DL tunnel info for the old (intermediate) UPF to the SMF. The SMF starts a timer, to be used in step 22a to release the resource in old intermediate UPF if there is one.
If the UPF that connects to RAN is the UPF (PSA), and if the SMF finds that the PDU Session is activated when receiving the Nsmf_PDUSession_UpdateSMContext Request in step 4 with Operation Type set to “UP activate” to indicate establishment of User Plane resources for the PDU Session(s), it deletes the AN Tunnel Info and initiates an N4 Session Modification procedure to remove Tunnel Info of AN in the UPF.
8a. [Conditional] SMF to old UPF (intermediate): N4 Session Modification Request (New UPF address, New UPF DL Tunnel ID)
If the service request is triggered by the network, and the SMF removes the old (intermediate) UPF, the SMF sends the N4 Session Modification Request message to the old (intermediate) UPF, providing the DL Tunnel Info for the buffered DL data. If the SMF allocated new I-UPF, the DL Tunnel Info is from the new (intermediate) UPF acting as N3 terminating point. If the SMF did not allocate a new I-UPF, the DL Tunnel Info is from the new UPF (PSA) acting as N3 terminating point. The SMF starts a timer to monitor the forwarding tunnel as step 6b or 7b.
If the SMF find the PDU Session is activated when receiving the Nsmf_PDUSession_UpdateSMContext Request in step 4 with Operation Type set to “UP activate” to indicate establishment of User Plane resources for the PDU Session(s), it deletes the AN Tunnel Info and initiates an N4 Session Modification procedure to remove Tunnel Info of AN in the UPF.
8b. old UPF (intermediate) to SMF: N4 Session Modification Response
The old (intermediate) UPF sends N4 Session Modification Response message to SMF.
9. [Conditional] old UPF (intermediate) to new UPF (intermediate): buffered downlink data forwarding
If the I-UPF is changed and forwarding tunnel was established to the new I-UPF, the old (intermediate) UPF forwards its buffered data to the new (intermediate) UPF acting as N3 terminating point.
10. [Conditional] old UPF (intermediate) to UPF (PSA): buffered downlink data forwarding
If the old I-UPF is removed and no new I-UPF is assigned for the PDU Session and forwarding tunnel was established to the UPF (PSA), the old (intermediate) UPF forwards its buffered data to the UPF (PSA) acting as N3 Terminating Point.
11. [Conditional] SMF to AMF: Nsmf_PDUSession_UpdateSMContext Response (N2 SM information (PDU Session ID, QFI(s), QoS profile(s), CN N3 Tunnel Info, S-NSSAI, User Plane Security Enforcement, UE Integrity Protection Maximum Data Rate), N1 SM Container, Cause) to the AMF. If the UPF that connects to RAN is the UPF (PSA), the CN N3 Tunnel Info is the UL Tunnel Info of the UPF (PSA). If the UPF that connects to RAN is the new intermediate UPF, the CN N3 Tunnel Info is the UL Tunnel Info of the intermediate UPF. The SMF shall send N1 SM Container and/or N2 SM Information to the AMF when applicable. (e.g. when the SMF was notified from the AMF that the access type of the PDU Session can be changed in step 4).
For a PDU Session that the SMF has determined to accept the activation of UP connection in step 5a or 5b, the SMF generates only N2 SM information and sends Nsmf_PDUSession_UpdateSMContext Response to the AMF to establish the User Plane(s). The N2 SM information contains information that the AMF shall provide to the NG-RAN. If the SMF decided to change the PSA UPF for the SSC mode 3 PDU Session, the SMF triggers the change of SSC mode 3 PDU Session anchor as an independent procedure described in clause 4.3.5.2 of 3GPP TS 23.502 or clause 4.3.5.3 of 3GPP TS 23.502 after accepting the activation of UP of the PDU Session.
For a PDU Session that the SMF has determined to accept the activation of UP connection in step 5a or 5b, the SMF also checks if there is any QoS Flow that is deleted in the 5GC but not synchronized with the UE yet. If such QoS Flows exist, the SMF includes the PDU Session Modification Command in N1 SM Container to delete those QoS Flows.
The SMF can reject the activation of UP of the PDU Session by including a cause in the Nsmf_PDUSession_UpdateSMContext Response. Following are some of the cases:
18a. [Conditional] SMF to UPF (PSA): N4 Session Modification Request (AN Tunnel Info, List of rejected QoS Flows).
If a User Plane is to be setup or modified and after the modification there is no I-UPF, the SMF initiates a N4 Session Modification procedure to UPF (PSA) and provides AN Tunnel Info. The Downlink Data from the UPF (PSA) can now be forwarded to NG-RAN and UE.
For QoS Flows in the List of rejected QoS Flows, the SMF shall instruct the UPF to remove the rules (e.g., Packet Detection Rules etc.) which are associated with the QoS Flows.
20a. [Conditional] SMF to new UPF (intermediate): N4 Session Modification Request.
If forwarding tunnel has been established to the new I-UPF and if the timer SMF set for forwarding tunnel at step 8a has expired, SMF sends N4 Session modification request to new (intermediate) UPF acting as N3 terminating point to release the forwarding tunnel.
20b. [Conditional] new UPF (intermediate) to SMF: N4 Session modification response.
New (intermediate) UPF acting as N3 terminating point sends N4 Session Modification response to SMF.
21a. [Conditional] SMF to UPF (PSA): N4 Session Modification Request. If forwarding tunnel has been established to the UPF (PSA) and if the timer SMF set for forwarding tunnel at step 7b has expired, SMF sends N4 Session modification request to UPF (PSA) acting as N3 Terminating Point to release the forwarding tunnel.
21b. [Conditional] UPF (PSA) to SMF: N4 Session Modification Response. UPF (PSA) acting as N3 Terminating Point sends N4 Session Modification Response to SMF.
If the SMF decided to continue using the old UPF in step 5b, the SMF sends an N4 Session Modification Request, providing AN Tunnel Info.
If the SMF decided to select a new UPF to act as intermediate UPF in step 5b, and the old UPF is not PSA UPF, the SMF initiates resource release, after timer in step 6b or 7b expires, by sending an N4 Session Release Request (Release Cause) to the old intermediate UPF.
22b. Old intermediate UPF to SMF: N4 Session Modification Response or N4 Session Release Response.
The old UPF acknowledges with an N4 Session Modification Response or N4 Session Release Response message to confirm the modification or release of resources.
For the mobility related events described in clause 4.15.4, the AMF invokes the Namf_EventExposure_Notify service operation after step 4.
Upon reception of the Namf_EventExposure_Notify with an indication that the UE is reachable, if the SMF has pending DL data the SMF invokes the Namf_Communication_N1N2MessageTransfer service operation to the AMF to establish the User Plane(s) for the PDU Sessions, otherwise the SMF resumes sending DL data notifications to the AMF in case of DL data.
UE or Network Requested PDU Session Modification (Non-Roaming and Roaming with Local Breakout)
The procedure may be triggered by following events:
1a. (UE initiated modification) The UE initiates the PDU Session Modification procedure by the transmission of an NAS message (N1 SM container (PDU Session Modification Request (PDU session ID, Packet Filters, Operation, Requested QoS, Segregation, 5GSM Core Network Capability)), PDU Session ID) message. Depending on the Access Type, if the UE was in CM-IDLE state, this SM-NAS message is preceded by the Service Request procedure. The NAS message is forwarded by the (R)AN to the AMF with an indication of User location Information. The AMF invokes Nsmf_PDUSession_UpdateSMContext (PDU Session ID, N1 SM container (PDU Session Modification Request)). When the UE requests specific QoS handling for selected SDF(s), the PDU Session Modification Request includes Packet Filters describing the SDF(s), the requested Packet Filter Operation (add, modify, delete) on the indicated Packet Filters, the Requested QoS and optionally a Segregation indication. The Segregation indication is included when the UE recommends to the network to bind the applicable SDF(s) on a distinct and dedicated QoS Flow e.g. even if an existing QoS Flow can support the requested QoS. The network should abide by the UE request, but is allowed to proceed instead with binding the selected SDF(s) on an existing QoS Flow.
NOTE 1: Only one QoS Flow is used for traffic segregation. If UE makes subsequent requests for segregation of additional SDF(s), the additional SDF(s) are multiplexed on the existing QoS Flow that is used for segregation.
The UE shall not trigger a PDU Session Modification procedure for a PDU Session corresponding to a LADN when the UE is outside the area of availability of the LADN.
The PS Data Off status, if changed, shall be included in the PCO in the PDU Session Modification Request message.
When PCF is deployed, the SMF shall further report the PS Data Off status to PCF if the PS Data Off event trigger is provisioned, the additional behaviour of SMF and PCF for 3GPP PS Data Off is defined in TS 23.503.
The 5GSM Core Network Capability is provided by the UE and handled by SMF as defined in TS 23.501 [2] clause 5.4.4b of 3GPP TS 23.502.
1b. (SMF requested modification) The PCF performs a PCF initiated SM Policy Association Modification procedure as defined in clause 4.16.5.2 of 3GPP TS 23.502 to notify SMF about the modification of policies. This may e.g.; have been triggered by a policy decision or upon AF requests, e.g. Application Function influence on traffic routing as described in step 5 in clause 4.3.6.2 of 3GPP TS 23.502.
1c. (SMF requested modification) The UDM updates the subscription data of SMF by Nudm_SDM_Notification (SUPI, Session Management Subscription Data). The SMF updates the Session Management Subscription Data and acknowledges the UDM by returning an Ack with (SUPI).
1d. (SMF requested modification) The SMF may decide to modify PDU Session. This procedure also may be triggered based on locally configured policy or triggered from the (R)AN (see clause 4.2.6 of 3GPP TS 23.502).
If the SMF receives one of the triggers in step 1b˜1d, the SMF starts SMF requested PDU Session Modification procedure.
1e. (AN initiated modification) (R)AN shall indicate to the SMF when the AN resources onto which a QoS Flow is mapped are released irrespective of whether notification control is configured. (R)AN sends the N2 message (PDU Session ID, N2 SM information) to the AMF. The N2 SM information includes the QFI, User location Information and an indication that the QoS Flow is released. The AMF invokes Nsmf_PDUSession_UpdateSMContext (N2 SM information). (AN initiated notification control) In case notification control is configured for a GBR Flow, (R)AN sends a N2 message (PDU Session ID, N2 SM information) to SMF when the (R)AN decides the QoS targets of the QoS Flow cannot be fulfilled or can be fulfilled again, respectively. The N2 SM information includes the QFI and an indication that the QoS targets for that QoS Flow cannot be fulfilled or can be fulfilled again, respectively. The AMF invokes Nsmf_PDUSession_UpdateSMContext (N2 SM information). If the PCF has subscribed to the event, SMF reports this event to the PCF for each PCC Rule for which notification control is set, see step 2. Alternatively, if dynamic PCC does not apply for this DNN, and dependent on locally configured policy, the SMF may start SMF requested PDU Session Modification procedure, see step 3b.
2. The SMF may need to report some subscribed event to the PCF by performing an SMF initiated SM Policy Association Modification procedure as defined in clause 4.16.5.1. This step may be skipped if PDU Session Modification procedure is triggered by step 1b or 1d. If dynamic PCC is not deployed, the SMF may apply local policy to decide whether to change the QoS profile. Steps 3 to 7 are not invoked when the PDU Session Modification requires only action at a UPF (e.g. gating).
3a. For UE or AN initiated modification, the SMF responds to the AMF through Nsmf_PDUSession_UpdateSMContext (N2 SM information (PDU Session ID, QFI(s), QoS Profile(s), Session-AMBR), 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))). See 3GPP TS 23.501 clause 5.7 for the QoS Profile, and QoS rule and QoS Flow level QoS parameters.
The N2 SM information carries information that the AMF shall provide to the (R)AN. It may include the QoS profiles and the corresponding QFIs to notify the (R)AN that one or more QoS flows were added, or modified. It may include only QFI(s) to notify the (R)AN that one or more QoS flows were removed. If the PDU Session Modification was triggered by the (R)AN Release in step 1 e the N2 SM information carries an acknowledgement of the (R)AN Release. If the PDU Session Modification was requested by the UE for a PDU Session that has no established User Plane resources, the N2 SM information provided to the (R)AN includes information for establishment of User Plane resources.
The N1 SM container carries the PDU Session Modification Command that the AMF shall provide to the UE. It may include the QoS rules, QoS Flow level QoS parameters if needed for the QoS Flow(s) associated with the QoS rule(s) and corresponding QoS rule operation and QoS Flow level QoS parameters operation to notify the UE that one or more QoS rules were added, removed or modified.
3b. For SMF requested modification, the SMF invokes Namf_Communication_N1N2MessageTransfer (N2 SM information (PDU Session ID, QFI(s), QoS Profile(s), Session-AMBR), N1 SM container (PDU Session Modification Command (PDU Session ID, QoS rule(s), QoS Flow level QoS parameters if needed for the QoS Flow(s) associated with the QoS rule(s), QoS rule operation and QoS Flow level QoS parameters operation, Session-AMBR))).
If the UE is in CM-IDLE state and an ATC is activated, the AMF updates and stores the UE context based on the Namf_Communication_N1N2MessageTransfer and steps 4, 5, 6 and 7 are skipped. When the UE is reachable e.g. when the UE enters CM-CONNECTED state, the AMF forwards the N1 message to synchronize the UE context with the UE.
4. The AMF may send N2 PDU Session Request (N2 SM information received from SMF, NAS message (PDU Session ID, N1 SM container (PDU Session Modification Command))) Message to the (R)AN.
5. The (R)AN may issue AN specific signalling exchange with the UE that is related with the information received from SMF. For example, in case of a NG-RAN, an RRC Connection Reconfiguration may take place with the UE modifying the necessary (R)AN resources related to the PDU Session.
6. The (R)AN may acknowledge N2 PDU Session Request by sending a N2 PDU Session Ack (N2 SM information (List of accepted/rejected QFI(s), AN Tunnel Info, PDU Session ID), User location Information) Message to the AMF. In case of Dual Connectivity, if one or more QFIs were added to the PDU Session, the Master RAN node may assign one or more of these QFIs to a NG-RAN node which was not involved in the PDU Session earlier. In this case the AN Tunnel Info includes a new N3 tunnel endpoint for QFIs assigned to the new NG-RAN node. Correspondingly, if one or more QFIs were removed from the PDU Session, a (R)AN node may no longer be involved in the PDU Session anymore, and the corresponding tunnel endpoint is removed from the AN Tunnel Info. The NG-RAN may reject QFI(s) if it cannot fulfill the User Plane Security Enforcement information for a corresponding QoS Profile, e.g. due to the UE Integrity Protection Maximum Data Rate being exceeded.
7. The AMF forwards the N2 SM information and the User location Information received from the AN to the SMF via Nsmf_PDUSession_UpdateSMContext service operation. The SMF replies with a Nsmf_PDUSession_UpdateSMContext Response.
If the (R)AN rejects QFI(s) the SMF is responsible of updating the QoS rules and QoS Flow level QoS parameters if needed for the QoS Flow(s) associated with the QoS rule(s) in the UE accordingly.
8. The SMF may update N4 session of the UPF(s) that are involved by the PDU Session Modification by sending N4 Session Modification Request message to the UPF. (see NOTE 2)
9. The UE acknowledges the PDU Session Modification Command by sending a NAS message (PDU Session ID, N1 SM container (PDU Session Modification Command Ack)) message.
10. The (R)AN forwards the NAS message to the AMF.
11. The AMF forwards the N1 SM container (PDU Session Modification Command Ack) and User Location Information received from the AN to the SMF via Nsmf_PDUSession_UpdateSMContext service operation. The SMF replies with a Nsmf_PDUSession_UpdateSMContext Response.
If the SMF initiated modification is to delete QoS Flows (e.g. triggered by PCF) and the SMF does not receive response from the UE, the SMF marks that the status of those GBR QoS Flows are to be synchronized with the UE.
12. The SMF may update N4 session of the UPF(s) that are involved by the PDU Session Modification by sending N4 Session Modification Request (N4 Session ID) message to the UPF. For a PDU Session of Ethernet PDU Session Type, the SMF may notify the UPF to add or remove Ethernet Packet Filter Set(s) and forwarding rule(s).
NOTE 2: The UPFs that are impacted in the PDU Session Modification procedure depends on the modified QoS parameters and on the deployment. For example in case of the session AMBR of a PDU Session with an UL CL changes, only the UL CL is involved. This note also applies to the step 8.
13. If the SMF interacted with the PCF in step 1b or 2, the SMF notifies the PCF whether the PCC decision could be enforced or not by performing an SMF initiated SM Policy Association Modification procedure as defined in clause 4.16.5.1 of 3GPP TS 23.502.
SMF notifies any entity that has subscribed to User Location Information related with PDU Session change.
If step 1b is triggered to perform Application Function influence on traffic routing by step 5 in clause 4.3.6.2 of 3GPP TS 23.502, the SMF may reconfigure the User Plane of the PDU Session as described in step 6 in clause 4.3.6.2 of 3GPP TS 23.502.
Step 710: SMF determines that one or more QoS flows for a PDU session should be deleted, where the one or more QoS flows is not associated to the default QoS rule. The one or more QoS flows are mainly GBR QoS flows, but they may be non-GBR QoS flows which are not associated to a default QoS rule as well. The deletion of the QoS flows (not associated to the default QoS rule) may be triggered by the PCF or internally or by other NF or by an Access Network, AN release procedure due to radio connection problem causing the radio connection to be lost with the UE. The SMF initiates the step of PDU session modification to delete/release/deactivate the QoS Flows in the UE. It sends a request for the UE via the AMF to trigger the release or deactivation of those QoS flows. Any relevant request which function is to delete the one or more QoS flows in the UE can be used.
Step 720: If the SMF does not receive a response or receives a failure notification from the AMF indicating that UE is not responding to the deactivation/release/delete of QoS flows request, the SMF executes the step of marking the status of those QoS Flows (GBR or non-GBR) as to be synchronized with the UE or deferring the procedure of deleting the GBR QoS Flows. Note that the SMF would continue with deactivation of the QoS flows in the network even if the UE fails to respond to the request. If the deletion of the QoS flows is triggered by another function, such as PCF, it will inform the PCF that the QoS flows are not released by the UE, but that it will synchronize with the UE at the next available opportunity, such as when the UE triggers a Service Request for activating the UP connections. The PCF may then notify the Application Function such as IMS P-CSCF.
The SMF therefore defers the QoS Flows (GBR and/or non-GBR) deactivation towards the UE. Optionally, the SMF may (if not already done) subscribe to UE reachability notification from the AMF, or waits for the UE to initiate a NAS Service request, or it could start a timer (guard timer).
Step 730 (optional): If the SMF receives from the AMF a request for activating the User Plane (e.g., NSMF_PDU Session_UpdateSMContext request) that may be triggered by a UE a Service Request or the like for activating the UP connections, and the request is accepted by the SMF, or if the guard time expires or if the SMF receives a notification from the AMF that the UE is reachable, the SMF then execute the step of checking if there is any QoS Flow that is deleted in the 5GC but not synchronized with the UE yet.
If the SMF received from the AMF a request for activating the User Plane (e.g., NSMF_PDU Session_UpdateSMContext request), the SMF would then send a response to the request to the AMF and includes a NAS PDU Session Modification Command in N1 SM Container, the AMF should forward the NAS message to the UE via the AN. The NAS PDU Session Modification Command is to delete those QoS Flows that were marked as to be synchronized with the UE.
The SMF would include in the NAS PDU Session Modification Command the Authorized QoS rules and the Authorized QoS flow descriptions that indicates the GBR (or non-GBR) QoS rules and GBR (or Non-GBR) QoS flows to be deactivated respectively. If mechanism of overall QoS rules and QoS flows status synchronization is used, SMF includes the QoS rules status and QoS flows status information in PDU Session Modification Command.
When the UE receives the PDU Session Modification Command from the AMF, it deactivates the GBR QoS rules and GBR QoS flows according to the Authorized QoS rules and Authorized QoS flow descriptions or QoS rules status and QoS flows status information sent from SMF.
If the synchronization is triggered by expiration of a guard time or a notification that UE is reachable, the SMF sends an request to the AMF, where the request includes the NAS PDU Session Modification Command indicating the QoS Flows (GBR, and optionally non-GBR) that should be deleted, similar to the above.
In another embodiment, If the UE has locally deactivated the QoS flows, but the was unable to update the network, the SMF receives from the AMF an Nsmf_PDUSession_UpdateSMContext request to SMF that includes the QoS rules status and QoS flows status, the SMF deactivates the GBR QoS rules and GBR QoS flows according to the Requested QoS rules and Requested QoS flow descriptions or QoS rules status and QoS flows status information sent from
Step 850: UE locally deactivating the GBR QoS flows but unable to notify the network (SMF). It defers the synchronization of the QoS Flows, may mark the QoS Flows as pending synchronization.
Step 860: When it regains the radio connection with the network, the UE executes the step of sending a PDU Session Modification request to AMF to indicate that some QoS flows GBR are deleted/deactivated. In the Requested QoS rules and Requested QoS flow descriptions of PDU Session Modification request, the UE indicates the GBR QoS rules and GBR QoS flows to be deactivated respectively. If mechanism of overall QoS rules status synchronization is used, UE includes the QoS rules status and QoS flows status information in PDU Session Modification request. The QoS rules status and QoS Flow Status indicate the current status of the GBR flows/rules that are activated in the UE, and may include information of the flows and rules that have been locally deactivated.
In addition, in embodiments in which the network node 800 is a radio access node, the network node 800 includes one or more radio units 810 that each includes one or more transmitters 812 and one or more receivers 814 coupled to one or more antennas 816. The radio units 810 may be referred to or be part of radio interface circuitry. In some embodiments, the radio unit(s) 810 is external to the control system 802 and connected to the control system 802 via, e.g., a wired connection (e.g., an optical cable). However, in some other embodiments, the radio unit(s) 810 and potentially the antenna(s) 816 are integrated together with the control system 802.
The one or more processors 804 operate to provide one or more functions of a network node 800, and in particular the functions of a network function(s) or service(s), as described herein. In some embodiments, the function(s) are implemented in software that is stored, e.g., in the memory 806 and executed by the one or more processors 804.
As used herein, a “virtualized” network node is an implementation of the network node 800 in which at least a portion of the functionality of the network node 800 is implemented as a virtual component(s) (e.g., via a virtual machine(s) executing on a physical processing node(s) in a network(s)). As illustrated, in some embodiments, the network node 800 includes the control system 802 that includes the one or more processors 804 (e.g., CPUs, ASICs, FPGAs, and/or the like), the memory 806, and the network interface 808 and, if the network node 800 is a radio access node, the one or more radio units 810 that each includes the one or more transmitters 812 and the one or more receivers 814 coupled to the one or more antennas 816, as described above. The control system 802 is connected to one or more processing nodes 900 coupled to or included as part of a network(s) 902 via the network interface 808. Each processing node 900 includes one or more processors 904 (e.g., CPUs, ASICs, FPGAs, and/or the like), memory 906, and a network interface 908.
In this example, functions 910 of the network node 800 (e.g., functions of the network function(s) or service(s) implemented by the network node 800) described herein are implemented at the one or more processing nodes 900 or distributed across the control system 802 and the one or more processing nodes 900 in any desired manner. In some particular embodiments, some or all of the functions 910 of the network node 800 described herein are implemented as virtual components executed by one or more virtual machines implemented in a virtual environment(s) hosted by the processing node(s) 900. As will be appreciated by one of ordinary skill in the art, additional signaling or communication between the processing node(s) 900 and the control system 802 is used in order to carry out at least some of the desired functions 910.
In some embodiments, a computer program including instructions which, when executed by at least one processor, causes the at least one processor to carry out the functionality of network node 800 or a node (e.g., a processing node 900) implementing one or more of the functions 910 of the radio access node 800 in a virtual environment according to any of the embodiments described herein is provided. In some embodiments, a carrier comprising the aforementioned computer program product is provided. The carrier is one of an electronic signal, an optical signal, a radio signal, or a computer readable storage medium (e.g., a non-transitory computer readable medium such as memory).
In some embodiments, a computer program including instructions which, when executed by at least one processor, causes the at least one processor to carry out the functionality of the wireless device 14 according to any of the embodiments described herein is provided. In some embodiments, a carrier containing the aforementioned computer program product is provided. The carrier is one of an electronic signal, an optical signal, a radio signal, or a computer readable storage medium (e.g., a non-transitory computer readable medium such as memory).
Any appropriate steps, methods, features, functions, or benefits disclosed herein may be performed through one or more functional units or modules of one or more virtual apparatuses. Each virtual apparatus may comprise a number of these functional units. These functional units may be implemented via processing circuitry, which may include one or more microprocessor or microcontrollers, as well as other digital hardware, which may include Digital Signal Processor (DSPs), special-purpose digital logic, and the like. The processing circuitry may be configured to execute program code stored in memory, which may include one or several types of memory such as Read Only Memory (ROM), Random Access Memory (RAM), cache memory, flash memory devices, optical storage devices, etc. Program code stored in memory includes program instructions for executing one or more telecommunications and/or data communications protocols as well as instructions for carrying out one or more of the techniques described herein. In some implementations, the processing circuitry may be used to cause the respective functional unit to perform corresponding functions according one or more embodiments of the present disclosure.
While processes in the figures may show a particular order of operations performed by certain embodiments of the present disclosure, it should be understood that such order is exemplary (e.g., alternative embodiments may perform the operations in a different order, combine certain operations, overlap certain operations, etc.).
While not being limited thereto, some other example embodiments of the present disclosure are provided below. Note that these are merely examples and may not necessarily be the final claims.
At least some of the following abbreviations may be used in this disclosure. If there is an inconsistency between abbreviations, preference should be given to how it is used above. If listed multiple times below, the first listing should be preferred over any subsequent listing(s).
| Number | Date | Country | Kind |
|---|---|---|---|
| PCT/CN2018/116113 | Nov 2018 | CN | national |
This application claims the benefit of provisional patent application serial number PCT/CN2018/116113, filed Nov. 19, 2018, the disclosure of which is hereby incorporated herein by reference in its entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2019/054503 | 5/30/2019 | WO | 00 |
