Devices and Methods for Supporting Handover of UE
20220167217 · 2022-05-26
Inventors
- Qing Wei (Munich, DE)
- Riccardo Trivisonno (Munich, DE)
- Apostolos Kousaridas (Munich, DE)
- Emmanouil Pateromichelakis (Munich, DE)
- Mirko Schramm (Berlin, DE)
Cpc classification
H04W28/24
ELECTRICITY
H04W28/0268
ELECTRICITY
International classification
H04W28/02
ELECTRICITY
H04W28/24
ELECTRICITY
Abstract
The present disclosure relates to handover (HO) of a user equipment (UE), which consumes a quality of service (QoS) flow that is associated with multiple QoS profiles. The disclosure proposes a network entity for supporting HO of the UE, and proposes a second network entity that is the target of HO of the UE. The network entity is configured to: obtain multiple QoS profiles associated with a QoS flow; obtain QoS capability information indicating whether the second network entity supports more than one QoS profile and/or whether a first network entity supports more than one QoS profile; and provide at least one message to the second network entity, wherein the at least one message includes at least one QoS profile according to the QoS capability information.
Claims
1. A network entity for supporting handover (HO) of a user equipment (UE) from a first network entity to a second network entity, the network entity comprising: a memory configured to store instructions; and a processor coupled to the memory and configured to execute the instructions to cause the network entity to: obtain multiple quality of service (QoS) profiles associated with a QoS flow; obtain QoS capability information indicating whether the second network entity and/or the first network entity supports more than one QoS profile in the multiple QoS profiles; and provide at least one message to the second network entity, wherein the at least one message includes at least one QoS profile in the multiple QoS profiles according to the QoS capability information.
2. The network entity of claim 1, wherein the multiple QoS profiles include an active QoS profile and at least one of an alternative QoS profile or a preferred QoS profile.
3. The network entity of claim 1, wherein the processor is configured to execute the instructions to further cause the network entity to obtain the QoS capability information via one of: receiving a message or notification indicating that the first network entity and/or the second network entity supports more than one QoS profile; or an operations administration, and maintenance (OAM) configuration.
4. The network entity of claim 1, wherein the network entity comprises the first network entity, wherein when the first network entity supports more than one QoS profile and the second network entity does not support more than one QoS profile, the first network entity is configured to provide multiple request messages to the second network entity, and wherein each of the multiple request messages, includes one of the multiple QoS profiles.
5. The network entity of claim 4, wherein the first network entity is further configured to: receive at least one acknowledgement message from the second network entity responsive to one of the multiple request messages, wherein the at least one acknowledgement message includes a respective QoS profile included in that request message, select a QoS profile from the respective QoS profile included in the at least one acknowledgement message; and support the HO of the UE to the second network entity based on the QoS profile.
6. The network entity of claim 5, wherein the first network entity is further configured to inform a core network entity about the QoS profile.
7. The network entity of claim 2, wherein the network entity comprises the first network entity, wherein when the first network entity supports more than one QoS profile and the second network entity does not support more than one QoS, the first network entity is configured to: provide a request message including the multiple QoS profiles to the second network entity; receive an acknowledgement message from the second network entity responsive to the request message, wherein the acknowledgement message is for the active QoS profile among the multiple QoS profiles; and support the HO of the UE to the second network entity based on the active QoS profile.
8. The network entity of claim 7, wherein the first network entity is further configured to inform a core network entity about the active QoS profile.
9. The network entity of claim 1, wherein the network entity comprises the first network entity or a session management function (SMF), wherein when the first network entity supports more than one QoS profile and the second network entity does not support more than one QoS profile, the processor is configured to execute the instructions to further cause the network entity to: select a QoS profile from the multiple QoS profiles; and provide a request message to the second network entity, wherein the request message includes the QoS profile.
10. The network entity of claim 2, wherein the network entity is a session management function (SMF) configured to provide to the second network entity a request message when the first network entity does not support more than one QoS profile and the second network entity supports more than one QoS profile, and wherein the request message includes the active QoS profile and other QoS profiles in the multiple QoS profiles.
11. The network entity of claim 10, wherein the SMF is further configured to: receive an acknowledgement message including one of the multiple QoS profiles from the second network entity; and continue the HO of the UE to the second network entity based on one of the multiple QoS profiles included in the acknowledgement message.
12. The network entity of claim 1, wherein the network entity is a session management function (SMF), and wherein when the first network entity does not support more than one QoS profile and the second network entity supports more than one QoS profile, the SMF is configured such that after completion of HO of the UE to the second network entity, the SMF provides a session modification message including the multiple QoS profiles to the second network entity.
13. The network entity of claim 1, wherein the network entity comprises the first network entity, wherein when the first network entity and the second network entity support more than one QoS profile, the first network entity is configured to: provide a request message including the multiple QoS profiles to the second network entity; receive an acknowledgement message including one of the multiple QoS profiles from the second network entity; and support the HO of the UE to the second network entity based on one of the multiple QoS profiles included in the acknowledgement message.
14. A second network entity for supporting handover (HO), of a user equipment (UE) from a first network entity, the second network entity comprising: a memory configured to store instructions; and a processor coupled to the memory and configured to execute the instructions to cause the second network entity to: receive, from the first network entity or a third network entity, a message including multiple quality of service (QoS) profiles associated with a QoS flow; select a QoS profile from one of the multiple QoS profiles in the message; and send a response message including the QoS profile to the first network entity or to the other network entity.
15. The second network entity of claim 14, wherein the processor is configured to execute the instructions to cause the second network entity to inform a core network entity comprising a session management function (SMF) about the QoS profile included in the response message.
16. The second network entity of claim 15, wherein the second network entity is configured to inform the SMF about the QoS profile after selection of one of the multiple QoS profiles and/or after completion of the HO of the UE.
17. The second network entity of claim 15, wherein the second network entity is configured to inform the SMF about the QoS profile using a new message or reusing an existing message.
18. The second network entity of claim 14, wherein the second network entity is configured to select the QoS profile from one of the multiple QoS profiles by selecting: an active QoS profile when the active QoS profile is supported by the second network entity; or a lower QoS profile than the active QoS profile when the active QoS profile is not supported by the second network entity.
19. The second network entity of claim 18, wherein the second network entity is further configured to select the QoS profile from one of the multiple QoS profiles by selecting a higher QoS profile than the active QoS profile when the active QoS profile and the higher QoS profile are supported by the second network entity.
20. A method for supporting handover (HO) of a user equipment (UE) from a first network entity to a second network entity, the method comprising: obtaining multiple quality of service (QoS) profiles associated with a QoS flow; obtaining QoS capability information indicating whether the second network entity and/or the first network entity supports more than one QoS profile in the multiple QoS profiles; and providing at least one message to the second network entity, wherein the at least one message includes at least one QoS profile according to the QoS capability information.
21. A method for supporting handover (HO) of a user equipment (UE) from a first network entity to a second network entity, the method comprising: receiving, from the first network entity or from a third network entity, a message including multiple quality of service (QoS) profiles associated with a QoS flow; selecting a QoS profile from one of the multiple QoS profiles in the message; and sending a response message including the QoS profile to the first network entity or to the third network entity.
Description
BRIEF DESCRIPTION OF DRAWINGS
[0106] The above described aspects and implementation forms of the present disclosure will be explained in the following description of specific embodiments in relation to the enclosed drawings.
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DETAILED DESCRIPTION OF EMBODIMENTS
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[0122] The network entity 100 may comprise processing circuitry (not shown) configured to perform, conduct or initiate the various operations of the network entity 100 described herein. The processing circuitry may comprise hardware and software. The hardware may comprise analog circuitry or digital circuitry, or both analog and digital circuitry. The digital circuitry may comprise components such as application-specific integrated circuits (ASICs), field-programmable arrays (FPGAs), digital signal processors (DSPs), or multi-purpose processors. In one embodiment, the processing circuitry comprises one or more processors and a non-transitory memory connected to the one or more processors. The non-transitory memory may carry executable program code which, when executed by the one or more processors, causes the network entity 100 to perform, conduct or initiate the operations or methods described herein.
[0123] The network entity 100 is configured to obtain multiple QoS profiles 105 (the group of QoS profiles being indicated by [105]) associated with a QoS flow 102. The QoS flow 102 may relate to an application or service that is consumed by the UE 101, e.g., a QoS flow, application or service that is provided to the UE 101 by the first network entity 110.
[0124] Further, the network entity 100 is configured to obtain QoS capability information 103 indicating whether the second network entity 200 supports more than one QoS profile 105 and/or whether the first network entity 110 supports more than one QoS profile 105. The network entity 100 may also obtain different QoS capability information, separately, related to the first network entity 110 and the second network entity 200, respectively.
[0125] The network entity 100 is further configured to provide at least one message 104, i.e., one message 104 or multiple messages 104, to the second network entity 200, wherein the one or more messages 104 include at least one QoS profile 105 according to the QoS capability information 103. That means, each of the one or more messages 104 may include at least one QoS profile 105. Whether a message 104 includes one or more QoS profiles 105 depends on the QoS capability information 103. How, based on the QoS capability information 103, the one or more QoS profiles 105 may be selected to be included in one or more messages 104, is explained below.
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[0127] The second network entity 200 is configured to receive, from the first network entity 110 or from another network entity (the latter is not shown), a message 201 including multiple QoS profiles 105 (the group of QoS profiles being indicated by [105]) associated with a QoS flow 102. The message 201 may be the message 104 shown in
[0128] The second network entity 200 is further configured to select one of the multiple QoS profiles 105 (i.e., select from those included in the message 201), and to send a response message 202 including the selected QoS profile 105 to the first network entity 110, or to the other network entity.
[0129] To facilitate further explanation of the multiple QoS profile 105 treatment supported by the network entities 100, 110, 200, according to embodiments of the disclosure, the following definitions are used in this document from the NG-RAN perspective. [0130] Original QoS profile 105a: received from SMF, which maps to the original requested QoS parameter sets from the PCF and the original requested service requirement from the AF. [0131] Alternative QoS profile(s) 105b: received from SMF, which maps to the alternative QoS parameters set(s) from the PCF and the alternative service requirement(s) from the AF. The alternative QoS profiles 105 are considered in case the original QoS profile cannot be fulfilled. [0132] Active QoS profile 105c: the QoS profile used by the RAN for the QoS flow (102).
[0133] The active QoS profile 105c can be either the original QoS profile 105a or can be one of the alternative QoS profile(s) 105b. The active QoS profile 105c, the original QoS profile 105a, and the alternative QoS profile(s) 105b may together form the multiple QoS profiles 105. In other words, the multiple QoS profiles 105 may include an active QoS profile 105c, and at least one alternative QoS profile 105b and/or a preferred or original QoS profile 105a.
[0134] The active QoS profile 105c can be either selected by the SMF/PCF, as described in 3GPP TS 23.287 (current agreed solution #27), or NG-RAN as described in 3GPP TR 23.786 (solution #16 option 2). The original QoS profile 105a is the preferred QoS profile, e.g., the QoS profile with the highest priority according to the application requirements (highest rank), i.e., the QoS profile that is associated with the highest QoS level.
[0135] An example implementation of alternative QoS profiles 105b list conveyed from 5GC to the NG-RAN is as shown below.
TABLE-US-00001 INDEX QoS PROFILE RANK/LEVEL/PRIORITY 0 requested QoS profile 0 1 alternative QoS profile 1 active QoS profile 2 alternative QoS profile 2 N alternative QoS profile 1
[0136] In the following, transfer of multiple QoS profiles 105 between/within RAN on the one hand, and from to 5GC to RAN on the other hand, during UE mobility, is described.
[0137] For support of multiple QoS profiles 105 (multi-level QoS profile) in a heterogeneous RAN deployment, the network entity 100 is able to convert the multiple QoS profiles to the right format according to the QoS capability information 103 (e.g., being a target NG-RAN node capability). The network entity 100 may be used in the protocol data unit (PDU) session setup/modification procedure, as well as in the HO procedures.
[0138] Four cases have been considered for HO as follows.
[0139] Case 1: Both the first network entity 110 (e.g., a source NG-RAN node) and the second network entity 200 (e.g., a target NG-RAN node) do not support multiple QoS profiles 105.
[0140] Case 2: The first network entity 110 supports multiple QoS profiles, but the second network entity 200 does not
[0141] Case 3: the first network entity 110 does not support multiple QoS profiles 105, but the second network entity 200 does.
[0142] Case 4: Both the first network entity 110 and the second network entity 200 support multiple QoS profiles 105.
[0143] The network entity 100 can be provided at (or in) the first network entity 110 (e.g., Xn-based HO). The first network entity 110 may be aware of the capability for support of multiple QoS profiles 105 at the second network entity 200 (i.e., of the QoS capability information 103 related to the second network entity 200). The network entity 100 can also be at (or in) the SMF (e.g., N2-based/NG-based HO). The first network entity 110 may could further be not aware of the capability for support of multiple QoS profiles 105 at the second network entity 200. In this case, a PDU session establishment/modification is included.
[0144] In Case 1, the NG-RAN uses/sends the active QoS profile 105c for mobility related procedures.
[0145] In Case 2, the following distinctions may be made. [0146] If the first network entity 110 knows that the second network entity 200 does not support more than one QoS profile 105 (e.g., via enhanced Automatic Neighbour Relation (ANR) or gNB capability exchange over Xn), for Xn-based HO, the network entity 100 (Note: the network entity 100 may here be the first network entity 110) can send multiple HO request messages (each a message 104 as shown in
[0151] In Case 3, following distinctions may be made. [0152] For N2-based HO, the first network entity 110 can send the active QoS profile 105c to the network entity 100 (Note: the network entity 100 may here be the SMF), and the network entity 100 changes it to a list of QoS profiles 105, and sends it to the second network entity 200 (e.g., via HO request message). [0153] For Xn-based HO, the first network entity 110 can send the active QoS profile 105c in QoS flow to-be-setup list to the second network entity 200 (e.g., HO request message). After the completion of HO, the network entity 100 (Note: the network entity 100 may here be the SMF) may trigger session modification message to change the active QoS profile to a list of QoS profile(s) 105.
[0154] In Case 4, the network entity 100 can use/send the complete list of QoS profile(s) 105 for mobility related procedures, either Xn-based or N2-based.
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[0156] In the following, admission control and HO execution is described.
[0157] In Cases 3 and 4, the second network entity 200 supports more than one QoS profile 105. The second network entity 200 thus may perform admission control based on the multiple QoS profiles 105. There can be distinguished different options regarding the admission control process of the second network entity 200 based on multiple QoS profiles 105 as follows. [0158] Option 1, downgrade only: The admission control of the second network entity 200 checks firstly the active QoS profile 105c of the first network entity 110, and if it is not supported, the admission control of the second network entity 200 checks only the downgrade case (e.g., checks for lower alternative QoS profile(s) 105b or the alternative QoS profile(s) which has/have lower priority than the active QoS profile). [0159] Option 2, both downgrade and upgrade: The admission control of the second network entity 200 checks firstly the active QoS profile 105c of the first network entity 110, and if it is not supported, the admission control of the second network entity 200 checks the downgrade case (lower alternative QoS profile(s) 105b or the alternative QoS profile(s) which has/have lower priority than the active QoS profile). In addition, the admission control of the second network entity 200 also checks the QoS upgrade case (higher alternative QoS profile(s) 105b or the alternative QoS profile(s) which has/have higher priority than the active QoS profile), if the active QoS profile 105 can be supported.
[0160] In an alternative implementation, the second network entity 200 could also receive the original QoS profile 105a as the active QoS profile 105c. Then only Option 1 as described above applies.
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[0162] In Case 2, the second network entity 200 does not support multiple QoS profiles. The second network entity 200 performs admission control on the selected QoS profile.
[0163] In the following, notification from RAN to the core network during HO procedure is described.
[0164] When there is a QoS downgrade/upgrade, due to a HO, an application running at the UE 101 can be notified using one of the following options. [0165] Option a: the HO command that is sent from the first network entity 110 the UE 101 may include an indication (e.g., a flag) used by UE access stratum to notify the (e.g., V2X) application. Then UE communication layer (access stratum) may notify the (e.g., V2X) application, just after the radio resource control (RRC) reconfiguration message reception. [0166] Option b: NG RAN may notify 5GC on the supported QoS profile 105. 5GC may notify the application server (or AF), and the application server notifies the application client at the UE 101.
[0167] The present disclosure focuses on the enhancement of Option b.
[0168] In Case 2, the second network entity 200 performs admission control based on selected QoS profile 105. In this case, the second network entity 200 does not support multiple QoS profiles 105.
[0169] The achievable QoS profile 105 can be included per multi_QoS profile QoS flow in N2 SM container in Nsmf_PDUsession_updateSMcontext_request, path switching message (Xn-based HO), and HO request acknowledge message (N2-based handover). [0170] For the successful setup QoS flows 102: enable upgrade. [0171] For the not successful setup QoS flows 102: enable downgrade.
[0172] In Case 3 or 4, the second network entity 200 may perform admission control based on the multiple QoS profiles 105.
[0173] The active QoS profile 105 can be included per multi_QoS profile QoS flow in N2 SM container in Nsmf_PDUsession_updateSMcontext_request, path switching message (Xn-based HO), and handover request acknowledge message (N2-based HO). [0174] For the successful setup QoS flows 102: enable downgrade and upgrade.
[0175] In an implementation, the RAN to 5GC QoS notification can be enhanced to include the achievable/supported QoS profile 105 during the mobility procedure, such that 5GC/AF can take one or more corresponding actions at the SMF/PCF or AF.
[0176] In an implementation, the achievable QoS profile 105 can be included in a QoS flow setup failure message (e.g., in case of a downgrade) or a QoS flow setup successful message (e.g., in case of an upgrade).
[0177] The notification can be sent to the 5GC either after the admission control (see e.g.,
[0178] Option 1 may be complemented with additional signaling with the information element of achievable QoS profile 105, QoS flow indication. Option 2 could reuse the existing signaling with an additional information element of achievable QoS profile 105.
[0179] In the following, some example implementations of the network entities 100, 110, 200 and of message sequences, according to embodiments of the disclosure, are shown.
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[0183] In the following, details of obtaining the multi-QoS support capability of RAN nodes, i.e., the QoS capability information 103, are described.
[0184] The QoS capability information 103 regarding the NG-RAN nodes (i.e., of the first network entity 110 and/or the second network entity 200) can be obtained via OAM configuration or an explicit message. The example in
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[0186] The method 1100 comprises: a step 1101 of obtaining multiple QoS profiles 105 associated with a QoS flow 102; a step 1102 of obtaining QoS capability information 103 indicating whether the second network entity 200 supports more than one QoS profile 105 and/or whether the first network entity 110 supports more than one QoS profile 105; and a step 1103 of providing at least one message 104 to the second network entity 200, wherein the at least one message 104 includes at least one QoS profile 105 according to the QoS capability information 103.
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[0188] The method 1200 comprises: a step 1201 of receiving, from the first network entity 110 or from another network entity, a message 201 including multiple QoS profiles 105 associated with a QoS flow 102; a step 1202 of selecting one of the multiple QoS profiles 105; and a step 1203 of sending a response message 202 including the selected QoS profile 105 to the first network entity 110 or to the other network entity.
[0189] In the case that a (target) NG-RAN node has stored alternative QoS profile(s), it is proposed to include the alternative QoS profile(s) in the handover request message that is sent from the source NG-RAN node to the target NG-RAN node. This will enable the admission control function of the target NG-RAN node to check an alternative QoS profile that could be fulfilled if the current QoS of the source NG-RAN node cannot be guaranteed.
[0190] It is proposed to support alternative QoS profile(s) during UE mobility (i.e., during a HO procedure).
[0191] It is proposed to introduce, as an option, the list of alternative QoS flow level QoS parameters in the handover request message.
[0192] If one of the alternative QoS profiles have been selected by the target NG-RAN node for one or more QoS flows then the handover request acknowledge message that is sent by the target NG-RAN node to the source NG-RAN node, includes the reference (or index) of the fulfilled QoS profile together the corresponding QoS flow identifier (i.e., admitted QoS flow).
[0193] An example of the index of the fulfilled QoS profile is: value 0 indicates initial QoS profile, value 1 indicates the first item of the alternative QoS profile list, value 2 indicates the second item of the alternative QoS profile, and so on about the prepared resources at the target.
[0194] It is proposed to introduce, as an option, in the handover request acknowledge message the fulfilled QoS profile for an admitted QoS flow that an alternative QoS profile can be fulfilled by the target NG-RAN node.
[0195] The proposed embodiments base on a unique signaling in the radio interface, N2 interface and Xn interfaces, which involves exchange of new messages; messages that are already available are enhanced with new content as well. Additionally, the interactions among the different network entities (e.g., UE 101, RAN nodes 110, 200, Mobility Management, etc.) involves unique messages exchanges and introduction of new NFs.
[0196] The present disclosure has been described in conjunction with various embodiments as examples as well as implementations. However, other variations can be understood and effected by those persons skilled in the art and practicing the claimed disclosure, from the studies of the drawings, this disclosure and the independent claims. In the claims as well as in the description the word “comprising” does not exclude other elements or steps and the indefinite article “a” or “an” does not exclude a plurality. A single element or other unit may fulfill the functions of several entities or items recited in the claims. The mere fact that certain measures are recited in the mutual different dependent claims does not indicate that a combination of these measures cannot be used in an advantageous implementation.
[0197] A communications apparatus is provided, including at least one of the following: a bus, a processor, a storage medium, a bus interface, a network adapter, a user interface, or an antenna, where the bus is configured to connect the processor, the storage medium, the bus interface, and the user interface; the processor is configured to perform the above method; the storage medium is configured to store an operating system and to-be-sent or to-be-received data; the bus interface is connected to the network adapter; the network adapter is configured to implement a signal processing function of a physical layer in a wireless communications network; the user interface is configured to be connected to a user input device; and the antenna is configured to send and receive a signal.
[0198] Another aspect of this application provides a computer-readable storage medium, where the computer-readable storage medium stores an instruction, and when the computer-readable storage medium runs on a computer, the computer performs the above method.
[0199] Another aspect of this application provides a computer program product including an instruction, where when the computer program product runs on a computer, the computer performs the above method.
[0200] Another aspect of this application provides a computer program, where when the computer program runs on a computer, the computer performs the above method.
[0201] Method or algorithm steps described with reference to the content disclosed in this application may be implemented by hardware, or may be implemented by a processor by executing a software instruction. The software instruction may include a corresponding software module. The software module may be stored in a random-access memory (RAM), a flash, a read-only memory (ROM), an erasable programmable ROM (EPROM), an electrically erasable programmable (EEPROM), a register, a hard disk, a removable hard disk, a compact-disc (CD)-ROM, or any other form of storage medium known in the art. For example, a storage medium is coupled to a processor, such that the processor can read information from the storage medium and write information into the storage medium. Certainly, the storage medium may be a component of the processor. The processor and the storage medium may be located in an ASIC. In addition, the ASIC may be located in user equipment. Certainly, the processor and the storage medium may exist in the user equipment as discrete components.
[0202] The foregoing embodiments may be all or partially implemented using software, hardware, firmware, or any combination thereof. When software is used to implement the embodiments, the embodiments may be all or partially implemented in a form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the procedures or functions according to the embodiments of this application are all or partially generated. The computer may be a general-purpose computer, a dedicated computer, a computer network, or other programmable apparatuses. The computer instructions may be stored in a computer readable storage medium, or may be transmitted from a computer readable storage medium to another computer readable storage medium. For example, the computer instructions may be transmitted from a website, computer, server, or data center to another website, computer, server, or data center in a wired (for example, a coaxial cable, an optical fiber, or a digital subscriber line (DSL)) or wireless (for example, infrared, radio, or microwave) manner. The computer readable storage medium may be any usable medium accessible by a computer, or may be a data storage device, such as a server or a data center, integrating one or more usable media.
[0203] The usable medium may be a magnetic medium (for example, a floppy disk, a hard disk, or a magnetic tape), an optical medium (for example, a DVD), a semiconductor medium (for example, a solid-state disk (SSD)), or the like.
[0204] The term “and/or” in this specification describes only an association relationship for describing associated objects and represents that three relationships may exist. For example, A and/or B may represent the following three cases: Only A exists, both A and B exist, and only B exists. In addition, the character “/” in this specification generally indicates an “or” relationship between the associated objects.
[0205] A person of ordinary skill in the art may be aware that, units and algorithm steps in the examples described with reference to the embodiments disclosed in this specification may be implemented by electronic hardware or a combination of computer software and electronic hardware. Whether the functions are performed by hardware or software depends on particular applications and design constraints of the technical solutions. A person skilled in the art may use different methods to implement the described functions for each particular application, but it should not be considered that the implementation goes beyond the scope of this application.
[0206] It may be clearly understood by a person skilled in the art that, for the purpose of convenient and brief description, for a detailed working process of the foregoing system, apparatus, and unit, refer to a corresponding process in the foregoing method embodiments. Details are not described herein again.
[0207] The foregoing descriptions are merely specific implementations of this application, but are not intended to limit the protection scope of this application. Any variation or replacement readily figured out by a person skilled in the art within the technical scope disclosed in this application shall fall within the protection scope of this application. Therefore, the protection scope of this application shall be subject to the protection scope of the claims.