WO2019227313A1

WO2019227313A1 - Method, apparatus and computer readable media for policy distribution

Info

Publication number: WO2019227313A1
Application number: PCT/CN2018/088885
Authority: WO
Inventors: Yang Shen; Alessio Casati
Original assignee: Nokia Shanghai Bell Co., Ltd.; Nokia Solutions And Networks Oy; Nokia Technologies Oy
Priority date: 2018-05-29
Filing date: 2018-05-29
Publication date: 2019-12-05
Also published as: CN112205015B; CN112205015A

Abstract

Embodiments of the present disclosure relate to methods, apparatuses and computer program products for policy distribution in a communication system. A method implemented at a network device comprises: receiving, from a terminal device, at least one of a request for policy synchronization and a device identifier; determining whether a policy rule is to be distributed to the terminal device, based on the received at least one of the request for policy synchronization and the device identifier; and controlling policy distribution to the terminal device based on the determination.

Description

METHOD, APPARATUS AND COMPUTER READABLE MEDIA FOR POLICY DISTRIBUTION

FIELD

Non-limiting and example embodiments of the present disclosure generally relate to a technical field of communication, and specifically to methods, apparatuses and computer program products for policy distribution in a communication system.

BACKGROUND

This section introduces aspects that may facilitate better understanding of the disclosure. Accordingly, the statements of this section are to be read in this light and are not to be understood as admissions about what is in the prior art or what is not in the prior art.

With development of communication techniques, more and more services/applications and more and more methods for accessing a network are provided to users. In order to improve resource utilization efficiency, to meet quality requirements for various services, and/or to allow the flexible operator configuration to the UE, a concept of user equipment (UE) policy has been proposed.

For example, with an introduction of the fifth generation (5G) communication technique, UE policies including UE access selection and Protocol Data Unit (PDU) Session related policy have been defined in technical specifications, such as TS 23.503 vfl0 developed by the third generation partnership project (3GPP) . According to the specifications of 3GPP, a 5G core network (5GC) shall be able to provide policy information from a Policy Control Function (PCF) to UE. UE policy rules provided by the PCF may be utilized by the UE together with the its locally pre-configured rules.

SUMMARY

Various embodiments of the present disclosure mainly aim at providing methods, apparatuses and computer program products for UE policy distribution in a communication system.

In a first aspect of the disclosure, there is provided a method implemented at a network device for policy distribution in a communication system. The method comprises: receiving at least one of a request for policy synchronization and a device identifier from a terminal device; determining whether a policy rule is to be distributed to the terminal device, based on the received at least one of the request for policy synchronization and the device identifier; and controlling policy distribution to the terminal device based on the determination.

In some embodiments, the determining may comprise: in response to receiving the device identifier, obtaining information on policy rules for a subscriber associated with the terminal device and a stored device identifier for the terminal device from a further network device; and in response to the received device identifier being different from the stored device identifier, determining to transmit all available policy rules for the subscriber to the terminal device. In some embodiments, the determining may further comprise: in response to the received device identifier being same as the stored device identifier, determining delivery statuses for the policy rules from the information on policy rules; and determining whether an updated policy rule is to be distributed to the terminal device based on the delivery statuses of policy rules. In some embodiments, the device identifier includes a Permanent Equipment Identifier (PEI) of the terminal device.

In a further embodiment, determining whether an updated policy rule is to be distributed to the terminal device may comprise: in response to the delivery status indicating that the latest version of a policy rule has not been delivered to the terminal device, determining the policy rule as the updated policy rule to be distributed to the terminal device; or in response to the delivery status indicating that the latest version of all policy rules have been delivered to be terminal device, determining that no policy rule is to be distributed to the terminal device.

In some embodiments, the information on policy rules may further include a rule identifier or a policy section identifier.

In still another embodiment, the determining may comprise: in response to receiving the request for policy synchronization, determining to transmit all available policy rules associated with the subscriber to the terminal device.

In some embodiments, controlling policy distribution to the terminal device may comprise: in response to determining that at least one policy rule is to be distributed to the terminal device, transmitting the at least one policy rule to the terminal device. In some embodiments, transmitting the at least one policy rule to the terminal device may comprise: in response to a size of the determined at least one policy rule exceeding a predetermined threshold, segmenting the determined at least one policy rule into a plurality of information sections with a size equal to or smaller than the predetermined threshold, and transmitting the plurality of information sections to the terminal device; or, in response to a size of the determined at least one policy rule being equal to or smaller than a predetermined threshold, transmitting the determined at least one policy rule to the terminal device without segmentation.

In some embodiments, the method may further comprise maintaining a policy rule, the device identifier and a delivery status for the policy rule for a subscriber associated with the terminal device; and in response to a policy Association for the terminal device being terminated, transmitting the PEI, a policy rule and the delivery status for the policy rule to a further network device. In some embodiments, maintaining the delivery status for the policy rule may comprise: in response to receiving a notification on update of a policy rule from the further network device, setting the delivery status for the policy rule to indicate that the latest version of the policy rule has not been delivered to be terminal device. In some embodiments, maintaining the delivery status for the policy rule for the terminal device may comprise: in response to receiving a message on successful delivery of a policy rule from the terminal device, setting the delivery status for the policy rule to indicate that the latest version of the policy rule has been delivered to the terminal device.

In a second aspect of the present disclosure, there is provided a method in a terminal device for policy distribution. The method comprises: transmitting, by a terminal device, at least one of a request for policy synchronization and a device identifier for determining policy distribution to a network device; and receiving policy rules for a subscriber associated with the terminal device from the network device.

In a third aspect of the present disclosure, there is provided a network device. The network device comprises at least one processor; and at least one memory including computer program codes; the at least one memory and the computer program codes are configured to, with the at least one processor, cause the network device at least to: receive, from a terminal device, at least one of a request for policy synchronization and a device identifier; determining whether a policy rule is to be distributed to the terminal device, based on the received at least one of the request for policy synchronization and the device identifier; and controlling policy distribution to the terminal device based on the determination.

In a fourth aspect of the present disclosure, there is provided a terminal device. The terminal device comprises at least one processor and at least one memory including computer program code. The at least one memory and the computer program code are configured to, with the at least one processor, cause the terminal device at least to transmit at least one of a request for policy synchronization and a device identifier for determining policy distribution to a network device; and receive at least one policy rule for a subscriber associated with the terminal device from the network device.

In a fifth aspect of the disclosure, there is provided a computer program. The computer program comprises instructions which, when executed by an apparatus, causes the apparatus to carry out the method according to the first aspect of the present disclosure.

In a sixth aspect of the disclosure, there is provided a computer program. The computer program comprises instructions which, when executed by an apparatus, causes the apparatus to carry out the method according to the second aspect of the present disclosure.

In a seventh aspect of the disclosure, there is provided a computer readable medium with a computer program stored thereon which, when executed by an apparatus, causes the apparatus to carry out the method of the first aspect of the present disclosure.

In an eighth aspect of the disclosure, there is provided a computer readable medium with a computer program stored thereon which, when executed by an apparatus, causes the apparatus to carry out the method of the second aspect of the present disclosure.

In a ninth aspect of the present disclosure, there is provided a terminal device. The terminal device comprises means for transmitting at least one of a request for policy synchronization and a device identifier for determining policy distribution to a network device; and means for receiving at least one policy rule associated with the terminal device from the network device.

In a tenth aspect of the present disclosure, there is provided a network device. The network device comprises means for receiving, from a terminal device, at least one of a request for policy synchronization and a device identifier; means for determining at least one policy rule to be distributed to the terminal device based on the received at least one of the request and the device identifier; and means for transmitting the determined at least one policy rules to the terminal device.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and benefits of various embodiments of the present disclosure will become more fully apparent from the following detailed description with reference to the accompanying drawings, in which like reference signs are used to designate like or equivalent elements. The drawings are illustrated for facilitating better understanding of the embodiments of the disclosure and are not necessarily drawn to scale, in which:

FIG. 1 illustrates an example communication network in which embodiments of the present disclosure may be implemented;

FIG. 2 shows an example procedure for policy distribution according to an embodiment of the present disclosure;

FIG. 3 shows a flowchart of a method at a network device for policy distribution according to an embodiment of the present disclosure;

FIGs. 4-5 show different example implementations for determining whether a policy is to be distributed to a terminal device according to embodiments of the present disclosure and a conventional method;

FIG. 6 shows a flowchart of a method in a terminal device according to an embodiment of the present disclosure; and

FIG. 7 illustrates a simplified block diagram of an apparatus that may be embodied as/in a network device or a terminal device.

DETAILED DESCRIPTION

Hereinafter, the principle and spirit of the present disclosure will be described with reference to illustrative embodiments. It should be understood that all these embodiments are given merely for one skilled in the art to better understand and further practice the present disclosure, but not for limiting the scope of the present disclosure. For example, features illustrated or described as part of one embodiment may be used with another embodiment to yield still a further embodiment. In the interest of clarity, not all features of an actual implementation are described in this specification.

References in the specification to “one embodiment, ” “an embodiment, ” “an example embodiment, ” and the like indicate that the embodiment described may include a particular feature, structure, or characteristic, but it is not necessary that every embodiment includes 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 affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

It shall be understood that although the terms “first” and “second” etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term “and/or” includes any and all combinations of one or more of the listed terms.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be liming of example embodiments. 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” , “has” , “having” , “includes” and/or “including” , when used herein, specify the presence of stated features, elements, and/or components etc., but do not preclude the presence or addition of one or more other features, elements, components and/or combinations thereof.

As used in this application, the term “circuitry” may refer to one or more or all of the following:

(a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry) and

(b) combinations of hardware circuits and software, such as (as applicable) :

(i) a combination of analog and/or digital hardware circuit (s) with software/firmware and

(ii) any portions of hardware processor (s) with software (including digital signal processor (s) ) , software, and memory (ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and

(c) hardware circuit (s) and or processor (s) , such as a microprocessor (s) or a portion of a microprocessor (s) , that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.

This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and/or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.

As used herein, the term “communication network” refers to a network following any suitable communication standards, such as 5G, New Radio (NR) , Long Term Evolution (LTE) , LTE-Advanced (LTE-A) , Wideband Code Division Multiple Access (WCDMA) , High-Speed Packet Access (HSPA) , and so on. The “communication network” may also be referred to as a “communication system. ” Furthermore, communications between network devices, between a network device and a terminal device, or between terminal devices in the communication network may be performed according to any suitable communication protocol, including, but not limited to, Global System for Mobile Communications (GSM) , Universal Mobile Telecommunications System (UMTS) , Long Term Evolution (LTE) , New Radio (NR) , 5G, wireless local area network (WLAN) standards, such as the IEEE 802.11 standards, and/or any other appropriate communication standard either currently known or to be developed in the future.

As used herein, the term “network device” refers to a node in a communication network via which a terminal device receives services and/or information related to the services. For example, the network device may include a network node in a core network (CN) , such as a PCF, an Access and Mobility Management Function (AMF) or a gateway.

The term “terminal device” refers to any end device that may be capable of communication. By way of example rather than limitation, a terminal device may also be referred to as a communication device, UE, a Subscriber Station (SS) , a Portable Subscriber Station, a Mobile Station (MS) , or an Access Terminal (AT) . The terminal device may include, but not limited to, a mobile phone, a cellular phone, a smart phone, voice over IP (VoIP) phones, wireless local loop phones, a tablet, a wearable terminal device, a personal digital assistant (PDA) , portable computers, desktop computer, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, vehicle-mounted wireless terminal devices, wireless endpoints, mobile stations, laptop-embedded equipment (LEE) , laptop-mounted equipment (LME) , USB dongles, smart devices, wireless customer-premises equipment (CPE) and the like. In the following description, the terms “terminal device” , “communication device” , “terminal” , “user equipment” and “UE” may be used interchangeably.

As yet another example, in an Internet of Things (IOT) scenario, a terminal 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 terminal device and/or network equipment. The terminal 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 terminal device may be a UE implementing the 3GPP narrow band internet of things (NB-IoT) standard. Examples of such machines or devices are sensors, metering devices such as power meters, industrial machinery, or home or personal appliances, for example refrigerators, televisions, personal wearables such as watches etc. In other scenarios, a terminal device may 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.

FIG. 1 illustrates an example communication network 100 in which embodiments of the present disclosure may be implemented. As shown, the communication network 100 may include an access network 110 and a core network (CN) 120. UE 111 may receive services from the core network 120 via a base station (BS) 112 in the access network 110. The core network 120 may include one or more network devices, such as a PCT 121, an AMF 122, a unified data repository (UDR) 123, and an application server (AS) 124. Note that the communication network 100 may include further access network, terminal devices and/or core network devices which are not shown in FIG. 1 for simplicity.

UE in a communication network may be offered various services which may have different quality of service (QoS) requirements with respect to delay or packet error rate. In order to improve resource utilization efficiency and/or to meet quality requirements for various services, UE policy information may be provided from a CN (e.g., a PCF in the CN) to the UE. Such UE policy information may include an Access Network Discovery &Selection Policy (ANDSP) and an UE Route Selection Policy (URSP) defined in 3GPP TS 23.503 and TS 23.402.

The ANDSP is used by the UE for selecting non-3GPP accesses and deciding how to route traffic between the selected 3GPP and non-3GPP accesses. The URSP is used by the UE to determine how to route outgoing traffic. For example, based on the URSP, UE may route the traffic to an established PDU Session, offloaded the traffic to non-3GPP access outside a PDU Session, or trigger establishment of a new PDU Session for the traffic. According to current 3GPP technical specifications, e.g., TS 23.503 vfl0, each URSP contains multiple URSP rules, and each URSP rule contains multiple RSDs, and the RSD is selected in an order of its precedence.

The structures of the ANDSP and URSP rules are described in Tables 6.6.1-1, 6.6.2.1-1, 6.6.2.1-2 and 6.6.2.1-3 of 3GPP TS 23.503vf10, which are reproduced below.

Table 6.6.1-1: Access Network Discovery &Selection Policy

Table 6.6.2.1-1: UE Route Selection Policy

Table 6.6.2.1-2: UE Route Selection Policy Rule

Table 6.6.2.1-3: Route Selection Descriptor

A UE policy may be stored in an UDR as a Data Subset "Policy Set Entry" of a Data Set "Policy Data" . The UE policy may be provided from the UDR to a PCF at UE context establishment using a Nudr service. Then the UE policy is distributed from the PCF to UE via an AMF in a container over a N 15 interface between the PCF and the AMF and a N1 interface between the AMF and the UE. The UE policy is transparent to the AMF.

Since N1 interface is a control plane interface between the AMF and the UE, distribution of a UE policy needs to consider a packet size limit of the N1 interface and signaling efficiency. A length of the UE policy to be distributed cannot be longer than the N1 size limit, and unnecessary signaling overload should be avoided. For example, if the UE policy rules are already installed in the UE, it should not be sent over and over if there’s no any update.

Current solutions for UE policy distribution are specified in 23.503 vf10, which are reproduced below:

- The PCF divides the UE policy by a Policy Clause Identifier (i.e. PSI) . e.g. The PCF may assign the URSP as one whole policy section, or it may subdivide the information in the URSP into multiple policy sections by assigning one or several URSP rules to each policy section.

- When providing the policy rules to the UE, the PCF provides the Policy Clause Identifier (s) (PSI) policy section (s) .

- At Initial Registration the UE provides the list of stored PSIs identifying the policy sections that are currently stored in the UE, if no policies are stored in the UE, UE does not provide any PSI. The UE may trigger an initial registration with the UE Policy Info to request a synchronization of UE policies for example when the UE powers up for the first time and has no policies;

- PCF receives UE policy request containing the list of stored PSIs, then it retrieves the list of PSIs and its content stored in the UDR for this SUPI. The PCF compares the two lists of PSIs, in addition the PCF checks whether the list of PSIs and its content needs to be updated according to operator policies. If the two lists of PSIs are different or an update is necessary, the PCF provide an updated list of PSIs and corresponding policy contents

- The PCF maintains the latest list of UE policy delivered to the UE until the AM Policy Association is terminated. Then PCF stores the latest list of PSIs and its contents in the UDR.

The above solutions specified in current 3GPP specification mixes a temporary usage of PSI for identifying a policy clause with a permanent identification for the policy rules. Some drawbacks of the solution are identified and will be illustrated by some examples below.

For illustration, assuming that UE is configured with URSP rules 1-12, and the rules are stored in an UDR in 4 sections identified by PSI 1-4, for example:

PSI 1 = URSP 1 +URSP 2 + URSP 3

PSI 2 = URSP 4 + URSP 5 + URSP 6

PSI 3 = URSP 7 + URSP 8 + URSP 9

PSI 4 = URSP 10 + URSP 11 + URSP 12.

Assuming that all URSP rules associated with the PSI 1-4 are distributed to the UE during initial registration of the UE. If PCF modifies URSP 1 and URSP 4 later due to an operator policy change or receiving a policy control request trigger from an AMF, and a total length of URSP 1 and URSP 4 is within the length limit of N1 interface, then one solution for distributing the updated URSP rules may be distributing the two updated rules in a single segmentation. However, it is unclear how to identify the new segmentation. Another solution may be distributing the two updated rules in 2 segmentations identified by PSI 1 and PSI 2 respectively. However, signaling overhead is increased unnecessarily in this solution.

Likewise, if the PCF modifies URSP 1+URSP 4+URSP 7+URSP 10, and the four URSP rules can be delivered within 2 segmentations, then one solution, denoted as Solution 1, may be distributing the rules in 2 segmentations identified by new PSIs, e.g. PSI 5 and PSI 6. Another solution, denoted as Solution 2, may be distributing the 4 rules in 4 segmentations identified by original PSI 1, PSI 2, PSI 3 and PSI 4 respectively. If Solution 1 is selected, the PSI -URSP association will not be unique any more, since a URSP rule is associated with two PSIs. For example, URSP 1 is associated with PSI 1 previously, then during update, it is associated with URSP 5. It may cause complexity in management of the UE policy. If Solution 2 is adopted, each URSP rule delivery requires a separate PSI, even if no segmentation is required. It means an increase in signaling overhead. Therefore, there are some drawbacks in current solutions for UE policy distribution.

In addition, inventors of the present disclosure have observed that PSI has to contain PLMN ID and other information, and therefore it may be very large. The large overhead may make the signaling more overloaded, especially for a non-3GPP access. Hence, unnecessary segmentation should be avoided as much as possible. Furthermore, PSI is defined to identify the policy clause only when the size of the UE policy is larger than packet size limit of N1 interface and the segmentation is required, and therefore, it may be unnecessary to associate a PSI permanently to fixed policy rules. Instead, PSI association with a policy rule may be valid only within the lifetime of an Access and Mobility Management (AM) Policy Association, within a transaction of the AM Policy Association, or within an AM Policy Association update, and it is unnecessary to carry it over from one AM Policy Association to another one. That is, at next UE initial registration, the PSI will be used for identifying another policy clause.

Further, it has been observed by inventors of the present disclosure that it may be unnecessary for the PCF to store the latest list of PSIs and its contents in the UDR during the termination of the AM Policy Association, as the PCF may record states of each UE policy rule without having to make them segmented and identified with a PSI.

Additionally, in current solutions specified in 3GPP, UE has to provide a list of stored PSIs identifying the policy sections that are currently stored in the UE at Initial Registration, although UDR has all knowledge of delivery status and versions of the UE policy rules. The inconsistence between UE and the UDR may only happen when some unexpected events occur, e.g. USIM swap, software or hardware problem.

On the other hand, UE has no knowledge of a version of a policy rule, i.e., even if UE provides the PSI, it may not be the latest version. For example, if UDR updated the UE policy that has been distributed to the UE after the AM policy association is deleted, there may be version inconsistency between the UE and the UDR. In such a case, it may cause problem if the UDR determines UE policy to be distributed to the UE based on PSI.

To solve at least part of the above problems and other potential problems, methods, apparatuses, and computer readable media for policy distribution have been proposed in the present disclosure.

In some embodiments, it is proposed that during lifetime of the AM Policy Association of the UE, PCF maintains states of a UE policy rule (e.g., one or more URSP rules, one or more ANDSP rules, or a subset thereof) . For example rather than limitation, the state of the UE policy rule may include a delivery status (which may be denoted as “Latest Version Delivery Status” ) indicating whether the latest version of the UE policy rule is successfully distributed/removed, and a device identifier (which may include Permanent Equipment Identifier (PEI) ) for identifying the UE device on which the policy rule is successfully installed. The states information of a UE policy rule facilitates the PCF to identify whether there’s SIM card swap at UE side, i.e., whether user moves a SIM card from one user device to another one. When an AM Policy Association is terminated, the PCF may stores the latest states and the content of each UE policy rule into the UDR. When UDR updates the content of the UE policy rule, it notifies the PCF, then the PCF updates the setting of the delivery status of the policy rule.

FIG. 2 shows an example procedure 200 for policy distribution according to an embodiment of the present disclosure. As shown in FIG. 2, during an initial registration, UE 201 may provide (210) at least one of a device identifier (e.g., PEI) and a request for policy synchronization (e.g., an indication of “UE policy synchronization required” ) , possibly together with a Subscription Permanent Identifier (SUPI) of the UE 201, to the PCF 202. The SUPI is a globally unique identifier which is allocated to each subscriber in the 5G System and provisioned in a Unified Data Management (UDM) /UDR, and may be used for identifying the UE context policy control subscription. The PEI is defined for a 3GPP UE accessing the 5G System, and may be used for facilitating the PCF to identify occurrence of a SIM card swap and determine a proper distribution strategy for UE policy rules. The request for policy synchronization may be utilized by the UE to inform the PCF that the UE wants to retrieve all the policy rules currently available to the UE. UE 201 may send (210) this request when a local problem (either software or hardware problem) happens on the UE and as a result the UE loses some or all the latest policy rules initially installed. This request may also be utilized by the PCF 202 to determine distribution of UE policy. The UE policy rule may include, but is not limited to, a ANDSP rule and/or a URSP rule.

In some embodiments, the above information may be provided to the PCF 202 via an AMF 203, as shown in FIG. 2. Upon receiving the information, the AMF 203 may initiate (220) an AMF Policy Association create request to the PCF 202. The request includes SUPI, and at least one of the PEI and the request for policy synchronization from the UE 201.

In some embodiments, upon receiving the AMF Policy Association create request, PCF 202 may retrieve (230) UE policy rules information and corresponding states from an UDR 204, and may compare the received PEI (if any) with the retrieved stored PEI. If they are different, or if “UE policy synchronization required” is included in the Access and Mobility Management (AM) Policy Association create request, the PCF 202 may respond by sending (250) all the policy rules currently available to the UE 201; otherwise, the PCF 202 may only distribute (250) updated/new policy rules to the UE 201. The updated/new policy ruled for the UE 201 may be determined (240) by the PCF 202 based on states of the UE policy rules. Such a scheme avoids unnecessary transmission of UE policy rules which have not been changed, and therefore saves network signaling overhead.

In some embodiments, the UE policy rule information to be distributed to the UE may be distributed directly by the PCF, or, segmented into clauses before distribution if its size exceeds a predefined size limit (e.g., a packet size limit of N1 interface) .

When PCF updates the UE policy rules, it may only distribute the updated information to the UE, and the updated information may or may not be segmented depending on the size of the updated policy rules.

FIG. 3 shows a flowchart of a method 300 implemented at a network device for policy distribution. The network device may be, for example, PCF 121 shown in FIG. 1 or the PCF 202 in FIG. 2. For ease of discussion, the method 300 will be described below with reference to PCF 121 and the communication network 100 illustrated in FIG. 1. However, embodiments of the present disclosure are not limited thereto.

At block 310, PCF 121 receives, from a terminal device (e.g., UE 111 in FIG. 1) , at least one of a request for policy synchronization and a device identifier. In some embodiments, the device identifier may include a PEI for the UE 111.

At block 320, PCF 121 determines whether a policy rule is to be distributed to the UE 111 based on the received information, i.e., the at least one of the request for policy synchronization and the device identifier. Some example implementations for the determining operation at block 320 are shown in FIG. 4 and FIG. 5.

In the example 400 shown in FIG. 4, if a device identifier (e.g., PEI) is received from UE 111 at block 410; at block 420, PCF 121 obtains/retrieve information on policy rules for a subscriber (e.g., identified by SUPI) associated with the UE 111 and a stored device identifier (e.g., PEI) for the UE 111 from a further network device, e.g., UDR 123 in FIG. 1. If PCF 121 determines, at block 430, that the received device identifier is different from the stored device identifier, it may determine, at block 440, to transmit all available policy rules associated with UE 111 to the UE.

On the other hand, if PCF 121 determines at block 430 that the received device identifier is same as the stored device identifier, it may further determine at block 450 delivery status for the policy rules from the retrieved information on policy rules. At block 460, PCF 121 determines whether an updated policy rule is to be transmitted to UE 111 based on the delivery status of policy rules. That is, in some embodiments, the information on policy rules may include delivery statuses of policy rules, and PCF 121 may utilize the delivery status of policy rules to determine whether and which policy rules is to be distributed to the UE 111. The delivery status may indicate whether the latest version of a policy rule has been delivered to the terminal device. For instance, if the delivery status indicates that the latest version of a policy rule has not been delivered to the terminal device, PCF 121 may determine the policy rule as the updated policy rule to be distributed to the terminal device at block 460. On the other hand, if the delivery status indicates that the latest version of all policy rules have been delivered to be terminal device, PCF 121 may determine that no policy rule is to be distributed to the terminal device at block 460.

In some embodiments, the information on policy rules retrieved from UDR 123 may further include a rule identifier. In such a case, the Data Model of a UE policy in the UDR 123 may be defined in a format as shown in Table 1.

Table 1. Example 1 for data model of a UE policy in UDR

Alternatively, in another embodiment, the information on policy rules may further include a policy section identifier. In such a case, the Data Model of a UE policy in the UDR 123 may be defined in a format as shown in Table 2.

Table 2. Example 2 for data model of a UE policy in UDR

In addition, the device identifier (e.g., PEI) may be stored in the UDR 123 as an information element (IE) of UE context policy control subscription information which may have a data model as shown in Table 3.

Table 3 Data model for UE context policy control subscription information in UDR

Fig. 5 shows another example 500 for determining whether a policy rule is to be distributed to UE 111. As shown in FIG. 5, if PCF 121 receives a request for policy synchronization from UE 111 at block 510, it may determine to transmit all available policy rules for a subscriber associated with the terminal device to the terminal device at block 520.

Now referring back to FIG. 3. At block 330, PCF 121 controls policy distribution to the terminal device based on the determination at block 320. For instance, if PCF 121 determines at block 320 that at least one policy rule is to be distributed to the UE 111, it transmits the at least one policy rule to UE 111 at block 330.

In some embodiment, to reduce signaling overhead, PCF 121 may determine whether to segment the at least one policy rule to be distributed before transmitting, based on a size of at least one policy rule. For example, if the size of the determined at least one policy rule exceeds a predetermined threshold, PCF 121 may segment the at least one policy rule into a plurality of information sections with a size equal to or smaller than the predetermined threshold, and transmit the plurality of information sections to UE 111. On the other hand, if the size of the at least one policy rule is equal to or smaller than the predetermined threshold, PCF 121 may transmit the determined at least one policy rule to UE 111 without segmentation.

In some embodiments, method 300 may further comprise operations in

blocks

340 and 350. At block 340, PCF 121 may maintain a delivery status for a policy rule for a subscriber associated with the UE 111, and possibly a device identifier for UE 111 and other information on the policy rule. For instance, ifPCF 121 receives a notification on update of a policy rule from a further network device (e.g., UDR 123 in FIG. 1) , it may set the delivery status for the policy rule to “No” , to indicate that the latest version of the policy rule has not been delivered to be terminal device. Alternatively or in addition, if PCF 121 receives a message on successful delivery of a policy rule from the UE 111, it may set the delivery status for the policy rule to “YES” , to indicate that the latest version of the policy rule has been delivered to the terminal device.

PCF 121 may maintain the delivery status for a policy rule, and possibly other information on the policy rule, during lifetime of a policy association (e.g., an AM policy association) for UE 111. For instance, if a policy Association for the terminal device is terminated, PCF 121 may transmit the PEI, a UE policy rule and the delivery status for the policy rule to the UDR 123, as shown in block 350 of FIG. 3. In such a case, PCF 121 may remove local information on the UE policy upon termination of an AM policy association of the UE 111.

FIG. 6 shows a flowchart of a method 600 implemented at a terminal device for policy distribution. The terminal device may be, for example, UE 111 shown in FIG. 1 or the UE 201 in FIG. 2. For ease of discussion, the method 600 will be described below with reference to UE 111 and the communication network 100 illustrated in FIG. 1. However, embodiments of the present disclosure are not limited thereto.

As shown in FIG. 6, at block 610, UE 111 transmits at least one of a request for policy synchronization and a device identifier (e.g., PEI) for determining policy distribution to a network device, e.g., PCF 121 in FIG. 1. In some embodiments, UE 111 may transmit the information to PCF 121 via one or more further network nodes, e.g., the AMF 122 in FIG. 1. In addition, in another embodiment, UE 111 may transmit the above information together with a SUPI, e.g., during initial registration. Alternatively or in addition, UE 111 may transmit the above information to PCF 121 when a local problem which causes loss of initially configured policies occurs. The information enables PCF 121 to make a better decision on which policy need to be distributed to UE 111, so as to avoid unnecessary signaling overhead.

At block 620, UE 111 receives at least one policy rule for a subscriber associated with it from PCF 121. In some embodiments, if UE 111 transmits a PEI to PCF 121 at block 610, and the PEI is same as that retrieved by PCF 121 from the UDR 123, UE 111 may only receive an updated UE policy (if any) from PCF 121. On the other hand, if the PEI transmitted by UE 111 at block 610 is different from the PEI retrieved by PCF 121 from the UDR 123, UE 111 mayreceive all UEpolicies from PCF 121 atblock 620. Alternatively or in addition, if UE 111 transmits the request for policy synchronization to PCF 121 at block 610, it may receive all UE policies at block 620 from PCF 121.

In some embodiments of the present disclosure, an apparatus for policy distribution is provided. The apparatus may be embodied in/as a network device, e.g., PCF 121 in FIG. 1 or PCF 202 in FIG. 2. The apparatus comprises means for receiving at least one of a request for policy synchronization and a device identifier from a terminal device; means for determining whether a policy rule is to be distributed to the terminal device based on the received at least one of the request for policy synchronization and the device identifier; and means for controlling policy distribution to the terminal device based on the determination.

In some embodiments of the present disclosure, a further apparatus for policy distribution is provided. The further apparatus may be embodied in/as a terminal device, e.g., UE 111 in FIG. 1 or UE 201 in FIG. 2. The apparatus comprises means for transmitting at least one of a request for policy synchronization and a device identifier for determining policy distribution to a network device; and means for receiving at least one policy rule for a subscriber associated with the terminal device from the network device.

FIG. 7 illustrates a simplified block diagram of an apparatus 700 that may be embodied in/as a terminal device, for example, the UE 111 shown in FIG. 1, or embodied in/as a network device, for example, PCF 121 shown in FIG. 1.

As shown by the example of FIG. 7, apparatus 700 comprises a processor 710 which controls operations and functions of apparatus 700. For example, in some embodiments, the processor 710 may implement various operations by means of instructions 730 stored in a memory 720 coupled thereto. The memory 720 may be any suitable type adapted to local technical environment and may be implemented using any suitable data storage technology, such as semiconductor based memory terminal devices, magnetic memory terminal devices and systems, optical memory terminal devices and systems, fixed memory and removable memory, as non-limiting examples. Though only one memory unit is shown in FIG. 7, a plurality of physically different memory units may exist in apparatus 700.

The processor 710 may be any proper type adapted to local technical environment, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors DSPs and processors based on multicore processor architecture, as non-limiting examples. The apparatus 700 may also comprise a plurality of processors 710.

The processors 710 may also be coupled with a transceiver 740 which enables reception and transmission of information. For example, the processor 710 and the memory 720 can operate in cooperation to implement

method

300 or 600 described with reference to FIGs. 2-6. It shall be appreciated that all the features described above with reference to FIGs. 2-6 also apply to apparatus 700, and therefore will not be detailed here.

Various embodiments of the present disclosure may be implemented by a computer program or a computer program product executable by one or more of the processors (for example processor 710 in FIG. 7) , software, firmware, hardware or in a combination thereof.

Although some of the above description is made in the context of a communication network shown in FIG. 1, it should not be construed as limiting the spirit and scope of the present disclosure. The principle and concept of the present disclosure may be more generally applicable to other scenarios.

In addition, the present disclosure may also provide a carrier containing the computer program as mentioned above (e.g., computer instructions/grogram 730 in FIG. 7) . The carrier includes a computer readable storage medium and a transmission medium. The computer readable storage medium may include, for example, an optical compact disk or an electronic memory device like a RAM (random access memory) , a ROM (read only memory) , Flash memory, magnetic tape, CD-ROM, DVD, Blue-ray disc and the like. The transmission medium may include, for example, electrical, optical, radio, acoustical or other form of propagated signals, such as carrier waves, infrared signals, and the like.

The techniques described herein may be implemented by various means so that an apparatus implementing one or more functions of a corresponding apparatus described with an embodiment comprises not only prior art means, but also means for implementing the one or more functions of the corresponding apparatus and it may comprise separate means for each separate function, or means that may be configured to perform two or more functions. For example, these techniques may be implemented in hardware (e.g., circuit or a processor) , firmware, software, or combinations thereof. For a firmware or software, implementation may be made through modules (e.g., procedures, functions, and so on) that perform the functions described herein.

Some example embodiments herein have been described above with reference to block diagrams and flowchart illustrations of methods and apparatuses. It will be appreciated that each block of the block diagrams and flowchart illustrations, and combinations of blocks in the block diagrams and flowchart illustrations, respectively, may be implemented by various means including computer program instructions. These computer program instructions may be loaded onto a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions which execute on the computer or other programmable data processing apparatus create means for implementing the functions specified in the flowchart block or blocks.

While this specification contains many specific implementation details, these should not be construed as limitations on the scope of any implementation or of what may be claimed, but rather as descriptions of features that may be specific to particular embodiments of particular implementations. Certain features that are described in this specification in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable sub-combination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a sub-combination or variation of a sub-combination.

It will be obvious to a person skilled in the art that, as the technology advances, the inventive concept may be implemented in various ways. The above described embodiments are given for describing rather than limiting the disclosure, and it is to be understood that modifications and variations may be resorted to without departing from the spirit and scope of the disclosure as those skilled in the art readily understand. Such modifications and variations are considered to be within the scope of the disclosure and the appended claims. The protection scope of the disclosure is defined by the accompanying claims.

Claims

A method for policy distribution in a communication system, comprising:

receiving, from a terminal device, at least one of a request for policy synchronization and a device identifier;

determining whether a policy rule is to be distributed to the terminal device, based on the received at least one of the request for policy synchronization and the device identifier; and

controlling policy distribution to the terminal device based on the determination.
The method of Claim 1, wherein the determining comprises:

in response to receiving the device identifier, obtaining information on policy rules for a subscriber associated with the terminal device and a stored device identifier for the terminal device from a further network device; and

in response to the received device identifier being different from the stored device identifier, determining to transmit all available policy rules for the subscriber to the terminal device.
The method of Claim 2, wherein the determining further comprises:

in response to the received device identifier being same as the stored device identifier, determining delivery statuses for the policy rules from the information on policy rules; and

determining whether an updated policy rule is to be distributed to the terminal device based on the delivery statuses of policy rules.
The method of Claim 3, wherein determining whether an updated policy rule is to be distributed to the terminal device based on the delivery statuses of policy rules comprises:

in response to the delivery status indicating that the latest version of a policy rule has not been delivered to be terminal device, determining the policy rule as the updated policy rule to be distributed to the terminal device; or

in response to the delivery status indicating that the latest version of all policy rules have been delivered to the terminal device, determining that no policy rule is to be distributed to the terminal device.
The method of Claim 2, wherein the information on policy rules further includes a rule identifier or a policy section identifier.
The method of Claim 1, wherein the determining comprises:

in response to receiving the request for policy synchronization, determining to transmit all available policy rules associated with the subscriber to the terminal device.
The method of Claim 1, wherein the device identifier includes a Permanent Equipment Identifier, PEI, of the terminal device.
The method of Claim 1, wherein controlling policy distribution to the terminal device comprises:

in response to determining that at least one policy rule is to be distributed to the terminal device, transmitting the at least one policy rule to the terminal device.
The method of Claim 8, wherein transmitting the at least one policy rule to the terminal device comprises:

in response to a size of the determined at least one policy rule exceeding a predetermined threshold, segmenting the determined at least one policy rule into a plurality of information sections with a size equal to or smaller than the predetermined threshold, and transmitting the plurality ofinformation sections to the terminal device; or,

in response to a size of the determined at least one policy rule being equal to or smaller than a predetermined threshold, transmitting the determined at least one policy rule to the terminal device without segmentation.
The method of Claim 1, further comprises:

maintaining a policy rule, the device identifier and a delivery status for the policy rule for a subscriber associated with the terminal device; and

in response to a policy Association for the terminal device being terminated, transmitting the policy rule, the device identifier and the delivery status for the policy rule to a further network device.
The method of Claim 10, wherein maintaining the delivery status for the policy rule comprises:

in response to receiving a notification on update of a policy rule from the further network device, setting the delivery status for the policy rule to indicate that the latest version of the policy rule has not been delivered to be terminal device.
The method of Claim 10, wherein maintaining the delivery status for the policy rule for the terminal device comprises:

in response to receiving a message on successful delivery of a policy rule from the terminal device, setting the delivery status for the policy rule to indicate that the latest version of the policy rule has been delivered to the terminal device.
A method of policy distribution in a communication system, comprising:

transmitting, by a terminal device, at least one of a request for policy synchronization and a device identifier for determining policy distribution to a network device; and

receiving policy rules for a subscriber associated with the terminal device from the network device.
The method of Claim 13, wherein the transmitting comprises:

transmitting the at least one of the request for policy synchronization and the device identifier to the network device during initial registration.
A network device, comprising:

at least one processor; and

at least one memory including computer program codes;

the at least one memory and the computer program codes are configured to, with the at least one processor, cause the network device at least to:

receive, from a terminal device, at least one of a request for policy synchronization and a device identifier;

determine whether a policy rule is to be distributed to the terminal device, based on the received at least one of the request for policy synchronization and the device identifier; and

control policy distribution to the terminal device based on the determination.
The network device of Claim 15, wherein the at least one memory and the computer program codes are configured to, with the at least one processor, cause the network device to determine the at least one policy rule by:

in response to receiving the device identifier, obtaining information on policy rules for a subscriber associated with the terminal device and a stored device identifier of the terminal device from a further network device; and

in response to the received device identifier being different from the stored device identifier, determining to transmit all available policy rules for the subscriber associated with the terminal device to the terminal device.
The network device of Claim 16, wherein the at least one memory and the computer program codes are configured to, with the at least one processor, cause the network device to determine the at least one policy rule further by:

in response to the received device identifier being same as the stored device identifier, determining delivery statuses for the policy rules from the information on policy rules;

determining whether an updated policy rule is to be transmitted to the terminal device based on the delivery statuses of policy rules.
The network device of Claim 17, wherein the at least one memory and the computer program codes are configured to, with the at least one processor, cause the network device to:

in response to the delivery status indicating that the latest version of a policy rule has not been delivered to the terminal device, determine the policy rule as the updated policy rule to be distributed to the terminal device; or

in response to the delivery status indicating that the latest version of all policy rules have been delivered to the terminal device, determine that no policy rule is to be distributed to the terminal device.
The network device of Claim 17, wherein the information on policy rules further includes a rule identifier or a policy section identifier.
The network de6vice of Claim 15, wherein the at least one memory and the computer program codes are configured to, with the at least one processor, cause the network device to determine by:

in response to receiving the request for policy synchronization, determining to transmit all available policy rules for a subscriber associated with the terminal device to the terminal device.
The network device of Claim 15, wherein the device identifier includes a Permanent Equipment Identifier, PEI, of the terminal device.
The network device of Claim 15, wherein the at least one memory and the computer program codes are configured to, with the at least one processor, cause the network device to controlling policy distribution to the terminal device by:

in response to determining that at least one policy rule is to be distributed to the terminal device, transmitting the at least one policy rule to the terminal device.
The network device of Claim 15, wherein the at least one memory and the computer program codes are configured to, with the at least one processor, cause the network device to transmit the determined at least one policy rule to the terminal device by:

in response to a size of the determined at least one policy rule exceeding a predetermined threshold, segmenting the determined at least one policy rule into a plurality of information sections with a size equal to or smaller than the predetermined threshold, and transmitting the plurality of information sections to the terminal device; or,

in response to a size of the determined at least one policy rule being equal to or smaller than a predetermined threshold, transmitting the determined at least one policy rule to the terminal device without segmentation.
The network device of Claim 15, wherein the at least one memory and the computer program codes are configured to, with the at least one processor, further cause the network device to:

maintain a policy rule, the device identifier and a delivery status for the policy rule for a subscriber associated with the terminal device; and

in response to a policy Association for the terminal device being terminated, transmit the policy rule, the device identifier and the delivery status for the policy rule to a further network device.
The network device of Claim 24, wherein the at least one memory and the computer program codes are configured to, with the at least one processor, cause the network device to maintain the delivery status for the policy rule by:

in response to receiving a notification on update of a policy rule from the further network device, setting the delivery status for the policy rule to indicate that the latest version of the policy rule has not been delivered to be terminal device.
The network device of Claim 24, wherein the at least one memory and the computer program codes are configured to, with the at least one processor, cause the network device to maintain the delivery status for the policy rule by:

in response to receiving a message on successful delivery of a policy rule from the terminal device, setting the delivery status for the policy rule to indicate that the latest version of the policy rule has been delivered to the terminal device.
A terminal device, comprising:

at least one processor; and

at least one memory including computer program codes;

the at least one memory and the computer program codes are configured to, with the at least one processor, cause the terminal device at least to:

transmit at least one of a request for policy synchronization and a device identifier for determining policy distribution to a network device; and

receive at least one policy rule for a subscriber associated with the terminal device from the network device.
The terminal device of Claim 27, wherein the at least one memory and the computer program codes are configured to, with the at least one processor, cause the terminal device to transmit the at least one of the request for policy synchronization and the device identifier to the network device during initial registration.
A network device, comprising:

means for receiving at least one of a request for policy synchronization and a device identifier from a terminal device;

means for determining whether a policy rule is to be distributed to the terminal device, based on the received at least one of the request for policy synchronization and the device identifier; and

means for controlling policy distribution to the terminal device based on the determination.
A terminal device, comprising:

means for transmitting at least one of a request for policy synchronization and a device identifier for determining policy distribution to a network device; and

means for receiving at least one policy rule for a subscriber associated with the terminal device from the network device.
A computer readable medium having a computer program stored thereon which, when executed by at least one processor of a device, causes the device to carry out the method of any of claims 1-12.
A computer readable medium having a computer program stored thereon which, when executed by at least one processor of a device, causes the device to carry out the method of any of claims 13-14.