WO2024086990A1

WO2024086990A1 - Solution for supporting charging

Info

Publication number: WO2024086990A1
Application number: PCT/CN2022/127130
Authority: WO
Inventors: Xiang Yang Li
Original assignee: Nokia Shanghai Bell Co., Ltd.; Nokia Solutions And Networks Oy
Priority date: 2022-10-24
Filing date: 2022-10-24
Publication date: 2024-05-02

Abstract

Embodiments of the present disclosure relate to a solution for supporting charging. An access management device in a first network transmits, to a policy control device in a second network via an interface between the access management device and the policy control device, a request for access information of a terminal device maintained in the second network for charging for a packet data unit (PDU) session of the terminal device, the PDU session being established in the first network via the second network; receives the access information of the terminal device in the second network from the policy control device in the second network via the interface; and transmits the access information to a session management device in the first network. Such that the first network can obtain the information from the second network for charging, and inter-operator charging can correctly implement.

Description

SOLUTION FOR SUPPORTING CHARGING

FIELD

Various example embodiments relate to the field of telecommunication and in particular, to methods, devices, apparatuses and computer readable storage medium for supporting charging.

BACKGROUND

In the communications area, there is a constant evolution ongoing in order to provide efficient and reliable solutions for utilizing wireless communication networks. Each new generation has it owns technical challenges for handling the different situations and processes that are needed to connect and serve devices connected to the wireless network. To meet the demand for wireless data traffic having increased since deployment of 4th generation (4G) communication systems, efforts have been made to develop an improved 5th generation (5G) or pre-5G communication system. The new communication systems can support various types of service applications for terminal devices.

With the development of charging technology under 5G network, a new solution for charging involving charging in different networks is needed.

SUMMARY

In general, example embodiments of the present disclosure provide a solution for supporting charging.

In a first aspect, there is provided an access management device in a first network. The access management device comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the access management device at least to transmit, to a policy control device in a second network via an interface between the access management device and the policy control device, a request for access information of a terminal device maintained in the second network for charging for a packet data unit (PDU) session of the terminal device, the PDU session being established in the first network via the second network; receive the access information of the terminal device in the second network from the policy control device in the second network via the interface; and transmit the access information of the terminal device in the second network to a session management device in the first network.

In a second aspect, there is provided a session management device in a first network. The session management device comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the session management device at least to receive, from an access management device in the first network, access information of a terminal device maintained in a second network for charging for a packet data unit (PDU) session of the terminal device, the PDU session being established in the first network via the second network; and transmit, to a charging device in the first network, a charging request comprising the access information of the terminal device in the second network.

In a third aspect, there is provided a charging device in a first network. The charging device comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the charging device at least to receive, from a session management device in the first network, a charging request comprising access information of a terminal device maintained in a second network, the access information being for charging for a packet data unit (PDU) session of the terminal device, the PDU session being established in the first network via the second network; generate a charging data record (CDR) in the first network for the PDU session based on the access information of the terminal device in the second network; and transmit the CDR in the first network to a billing device in the first network.

In a fourth aspect, there is provided a first billing device in a first network. The first billing device comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the first billing device at least to receive, from a charging device in the first network, a first charging data record (CDR) in the first network for a packet data unit (PDU) session of a terminal device, the PDU session being established in the first network via a second network; receive, from a second billing device in the second network, a second CDR in the second network for the PDU session; and correlate the first CDR and the second CDR.

In a fifth aspect, there is provided a policy control device in a second network. The policy control device comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the policy control device at least to receive, from an access management device in a first network via an interface between the access management device and the policy control device, a request for access information of a terminal device maintained in the second network for charging for a packet data unit (PDU) session of the terminal device, the PDU session being established in the first network via the second network; and transmit the access information of the terminal device in the second network to the access management device in the first network via the interface.

In a sixth aspect, there is provided a session management device in a second network. The session management device comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the session management device at least to receive, from a policy control device in the second network, charging correlation information for a packet data unit (PDU) session of a terminal device, the PDU session being established in a first network via the second network; and transmit, to a charging device in the second network device, a charging request comprising the charging correlation information.

In a seventh aspect, there is provided a charging device in a second network. The charging device comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the charging device at least to receive, from a session management device in the second network, a charging request comprising charging correlation information for a packet data unit (PDU) session of a terminal device, the PDU session being established in a first network via the second network; generate a charging data record (CDR) in the second network for the PDU session based on the charging correlation information; and transmit the CDR in the second network to a billing device in the second network.

In an eighth aspect, there is provided a second billing device in a second network. The second billing device comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the second billing device at least to receive, from a charging device in the second network, a charging data record (CDR) in the second network for a packet data unit (PDU) session of a terminal device, the PDU session being established in a first network via a second network; and transmit the CDR to a first billing device in the first network.

In a ninth aspect, there is provided a method implemented at an access management device in a first network. The method comprises transmitting, at an access management device in a first network, to a policy control device in a second network via an interface between the access management device and the policy control device, a request for access information of a terminal device maintained in the second network for charging for a packet data unit (PDU) session of the terminal device, the PDU session being established in the first network via the second network; receiving the access information of the terminal device in the second network from the policy control device in the second network via the interface; and transmitting the access information of the terminal device in the second network to a session management device in the first network.

In a tenth aspect, there is provided a method implemented at a session management device in a first network. The method comprises receiving, at a session management device in a first network from an access management device in the first network, access information of a terminal device maintained in a second network for charging for a packet data unit (PDU) session of the terminal device, the PDU session being established in the first network via the second network; and transmitting, to a charging device in the first network, a charging request comprising the access information of the terminal device in the second network.

In an eleventh aspect, there is provided a method implemented at a charging device in a first network. The method comprises receiving, at a charging device in a first network from a session management device in the first network, a charging request comprising access information of a terminal device maintained in a second network, the access information being for charging for a packet data unit (PDU) session of the terminal device, the PDU session being established in the first network via the second network; generating a charging data record (CDR) in the first network for the PDU session based on the access information of the terminal device in the second network; and transmitting the CDR in the first network to a billing device in the first network.

In a twelfth aspect, there is provided a method implemented at a first billing device in a first network. The method comprises receiving, at a first billing device in a first network from a charging device in the first network, a first charging data record (CDR) in the first network for a packet data unit (PDU) session of a terminal device, the PDU session being established in the first network via a second network; receiving, from a second billing device in the second network, a second CDR in the second network for the PDU session; and correlating the first CDR and the second CDR.

In a thirteenth aspect, there is provided a method implemented at a policy control device in a second network. The method comprises receiving, at a policy control device in a second network from an access management device in a first network via an interface between the access management device and the policy control device, a request for access information of a terminal device maintained in the second network for charging for a packet data unit (PDU) session of the terminal device, the PDU session being established in the first network via the second network; and transmitting the access information of the terminal device in the second network to the access management device in the first network via the interface.

In a fourteenth aspect, there is provided a method implemented at a session management device in a second network. The method comprises receiving, at a session management device in a second network from a policy control device in the second network, charging correlation information for a packet data unit (PDU) session of a terminal device, the PDU session being established in a first network via the second network; and transmitting, to a charging device in the second network device, a charging request comprising the charging correlation information.

In a fifteenth aspect, there is provided a method implemented at a charging device in a second network. The method comprises receiving, at a charging device in a second network from a session management device in the second network, a charging request comprising charging correlation information for a packet data unit (PDU) session of a terminal device, the PDU session being established in a first network via the second network; generating a charging data record (CDR) in the second network for the PDU session based on the charging correlation information; and transmitting the CDR in the second network to a billing device in the second network.

In a sixteenth aspect, there is provided a method implemented at a second billing device in a second network. The method comprises receiving, at a second billing device in a second network from a charging device in the second network, a charging data record (CDR) in the second network for a packet data unit (PDU) session of a terminal device, the PDU session being established in a first network via a second network; and transmitting the CDR to a first billing device in the first network.

In a seventeenth aspect, there is provided an apparatus. The apparatus comprises means for transmitting, at an access management device in a first network, to a policy control device in a second network via an interface between the access management device and the policy control device, a request for access information of a terminal device maintained in the second network for charging for a packet data unit (PDU) session of the terminal device, the PDU session being established in the first network via the second network; means for receiving the access information of the terminal device in the second network from the policy control device in the second network via the interface; and means for transmitting the access information of the terminal device in the second network to a session management device in the first network.

In an eighteenth aspect, there is provided an apparatus. The apparatus comprises means for receiving, at a session management device in a first network from an access management device in the first network, access information of a terminal device maintained in a second network for charging for a packet data unit (PDU) session of the terminal device, the PDU session being established in the first network via the second network; and means for transmitting, to a charging device in the first network, a charging request comprising the access information of the terminal device in the second network.

In a nineteenth aspect, there is provided an apparatus. The apparatus comprises means for receiving, at a charging device in a first network from a session management device in the first network, a charging request comprising access information of a terminal device maintained in a second network, the access information being for charging for a packet data unit (PDU) session of the terminal device, the PDU session being established in the first network via the second network; means for generating a charging data record (CDR) in the first network for the PDU session based on the access information of the terminal device in the second network; and means for transmitting the CDR in the first network to a billing device in the first network.

In a twentieth aspect, there is provided an apparatus. The apparatus comprises means for receiving, at a first billing device in a first network from a charging device in the first network, a first charging data record (CDR) in the first network for a packet data unit (PDU) session of a terminal device, the PDU session being established in the first network via a second network; means for receiving, from a second billing device in the second network, a second CDR in the second network for the PDU session; and means for correlating the first CDR and the second CDR.

In a twenty-first aspect, there is provided an apparatus. The apparatus comprises means for receiving, at a policy control device in a second network from an access management device in a first network via an interface between the access management device and the policy control device, a request for access information of a terminal device maintained in the second network for charging for a packet data unit (PDU) session of the terminal device, the PDU session being established in the first network via the second network; and means for transmitting the access information of the terminal device in the second network to the access management device in the first network via the interface.

In a twenty-second aspect, there is provided an apparatus. The apparatus comprises means for receiving, at a session management device in a second network from a policy control device in the second network, charging correlation information for a packet data unit (PDU) session of a terminal device, the PDU session being established in a first network via the second network; and means for transmitting, to a charging device in the second network device, a charging request comprising the charging correlation information.

In a twenty-third aspect, there is provided an apparatus. The apparatus comprises means for receiving, at a charging device in a second network from a session management device in the second network, a charging request comprising charging correlation information for a packet data unit (PDU) session of a terminal device, the PDU session being established in a first network via the second network; means for generating a charging data record (CDR) in the second network for the PDU session based on the charging correlation information; and means for transmitting the CDR in the second network to a billing device in the second network.

In a twenty-fourth aspect, there is provided an apparatus. The apparatus comprises means for receiving, at a second billing device in a second network from a charging device in the second network, a charging data record (CDR) in the second network for a packet data unit (PDU) session of a terminal device, the PDU session being established in a first network via a second network; and means for transmitting the CDR to a first billing device in the first network.

In a twenty-fifth aspect, there is provided a non-transitory computer readable medium comprising program instructions for causing an apparatus to perform at least the method according to any one of the above ninth to sixteenth aspect.

In a twenty-sixth aspect, there is provided a non-transitory computer readable medium comprising program instructions stored thereon for performing at least the method according to any one of the above ninth to sixteenth aspect.

In a twenty-seventh aspect, there is provided a computer program comprising instructions, which, when executed by an apparatus, cause the apparatus at least to transmit, to a policy control device in a second network via an interface between the access management device and the policy control device, a request for access information of a terminal device maintained in the second network for charging for a packet data unit (PDU) session of the terminal device, the PDU session being established in the first network via the second network; receive the access information of the terminal device in the second network from the policy control device in the second network via the interface; and transmit the access information of the terminal device in the second network to a session management device in the first network.

In a twenty-eighth aspect, there is provided a computer program comprising instructions, which, when executed by an apparatus, cause the apparatus at least to receive, from an access management device in the first network, access information of a terminal device maintained in a second network for charging for a packet data unit (PDU) session of the terminal device, the PDU session being established in the first network via the second network; and transmit, to a charging device in the first network, a charging request comprising the access information of the terminal device in the second network.

In a twenty-nine aspect, there is provided a computer program comprising instructions, which, when executed by an apparatus, cause the apparatus at least to receive, from a session management device in the first network, a charging request comprising access information of a terminal device maintained in a second network, the access information being for charging for a packet data unit (PDU) session of the terminal device, the PDU session being established in the first network via the second network; generate a charging data record (CDR) in the first network for the PDU session based on the access information of the terminal device in the second network; and transmit the CDR in the first network to a billing device in the first network.

In a thirtieth aspect, there is provided a computer program comprising instructions, which, when executed by an apparatus, cause the apparatus at least to receive, from a charging device in the first network, a first charging data record (CDR) in the first network for a packet data unit (PDU) session of a terminal device, the PDU session being established in the first network via a second network; receive, from a second billing device in the second network, a second CDR in the second network for the PDU session; and correlate the first CDR and the second CDR.

In a thirty-first aspect, there is provided a computer program comprising instructions, which, when executed by an apparatus, cause the apparatus at least to receive, from an access management device in a first network via an interface between the access management device and the policy control device, a request for access information of a terminal device maintained in the second network for charging for a packet data unit (PDU) session of the terminal device, the PDU session being established in the first network via the second network; and transmit the access information of the terminal device in the second network to the access management device in the first network via the interface.

In a thirty-second aspect, there is provided a computer program comprising instructions, which, when executed by an apparatus, cause the apparatus at least to receive, from a policy control device in the second network, charging correlation information for a packet data unit (PDU) session of a terminal device, the PDU session being established in a first network via the second network; and transmit, to a charging device in the second network device, a charging request comprising the charging correlation information.

In a thirty-third aspect, there is provided a computer program comprising instructions, which, when executed by an apparatus, cause the apparatus at least to receive, from a session management device in the second network, a charging request comprising charging correlation information for a packet data unit (PDU) session of a terminal device, the PDU session being established in a first network via the second network; generate a charging data record (CDR) in the second network for the PDU session based on the charging correlation information; and transmit the CDR in the second network to a billing device in the second network.

In a thirty-fourth aspect, there is provided a computer program comprising instructions, which, when executed by an apparatus, cause the apparatus at least to receive, from a charging device in the second network, a charging data record (CDR) in the second network for a packet data unit (PDU) session of a terminal device, the PDU session being established in a first network via a second network; and transmit the CDR to a first billing device in the first network.

In a thirty-fifth aspect, there is provided an access management device in a first network comprising: first transmitting circuitry configured to transmit, to a policy control device in a second network via an interface between the access management device and the policy control device, a request for access information of a terminal device maintained in the second network for charging for a packet data unit (PDU) session of the terminal device, the PDU session being established in the first network via the second network; receiving circuitry configured to receive the access information of the terminal device in the second network from the policy control device in the second network via the interface; and second transmitting circuitry configured to transmit the access information of the terminal device in the second network to a session management device in the first network.

In a thirty-sixth aspect, there is provided a session management device in a first network comprising: receiving circuitry configured to receive, from an access management device in the first network, access information of a terminal device maintained in a second network for charging for a packet data unit (PDU) session of the terminal device, the PDU session being established in the first network via the second network; and transmitting circuitry configured to transmit, to a charging device in the first network, a charging request comprising the access information of the terminal device in the second network.

In a thirty-seventh aspect, there is provided a charging device in a first network, comprising: receiving circuitry configured to receive, from a session management device in the first network, a charging request comprising access information of a terminal device maintained in a second network, the access information being for charging for a packet data unit (PDU) session of the terminal device, the PDU session being established in the first network via the second network; generating circuitry configured to generate a charging data record (CDR) in the first network for the PDU session based on the access information of the terminal device in the second network; and transmitting circuitry configured to transmit the CDR in the first network to a billing device in the first network.

In a thirty-eighth aspect, there is provided a first billing device in a first network, comprising: first receiving circuitry configured to receive, from a charging device in the first network, a first charging data record (CDR) in the first network for a packet data unit (PDU) session of a terminal device, the PDU session being established in the first network via a second network; second receiving circuitry configured to receive, from a second billing device in the second network, a second CDR in the second network for the PDU session; and correlating circuitry configured to correlate the first CDR and the second CDR.

In a thirty-ninth aspect, there is provided a policy control device in a second network, comprising: receiving circuitry configured to receive, from an access management device in a first network via an interface between the access management device and the policy control device, a request for access information of a terminal device maintained in the second network for charging for a packet data unit (PDU) session of the terminal device, the PDU session being established in the first network via the second network; and transmitting circuitry configured to transmit the access information of the terminal device in the second network to the access management device in the first network via the interface.

In a fortieth aspect, there is provided a session management device in a second network, comprising: receiving circuitry configured to receive, from a policy control device in the second network, charging correlation information for a packet data unit (PDU) session of a terminal device, the PDU session being established in a first network via the second network; and transmitting circuitry configured to transmit, to a charging device in the second network device, a charging request comprising the charging correlation information.

In a forty-first aspect, there is provided a charging device in a second network, comprising: receiving circuitry configured to receive, from a session management device in the second network, a charging request comprising charging correlation information for a packet data unit (PDU) session of a terminal device, the PDU session being established in a first network via the second network; generating circuitry configured to generate a charging data record (CDR) in the second network for the PDU session based on the charging correlation information; and transmitting circuitry configured to transmit the CDR in the second network to a billing device in the second network.

In a forty-second aspect, there is provided a second billing device in a second network, comprising: receiving circuitry configured to receive, from a charging device in the second network, a charging data record (CDR) in the second network for a packet data unit (PDU) session of a terminal device, the PDU session being established in a first network via a second network; and transmitting circuitry configured to transmit the CDR to a first billing device in the first network.

It is to be understood that the summary section is not intended to identify key or essential features of embodiments of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will become easily comprehensible through the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

Some example embodiments will now be described with reference to the accompanying drawings, where:

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

Fig. 1B illustrates a schematic diagram illustrating non-roaming architecture for 5G Core Network with untrusted non-3GPP access;

Fig. 1C illustrates a schematic diagram illustrating access to Stand-alone Non-Public Network services via PLMN;

Fig. 1D illustrates a schematic diagram illustrating access to PLMN services via Stand-alone Non-Public Network;

Fig. 2 illustrates a call flow diagram according to some embodiments of the present disclosure;

Fig. 3 illustrates a call flow diagram according to some other embodiments of the present disclosure;

Fig. 4 illustrates a call flow diagram according to some other embodiments of the present disclosure;

Fig. 5 illustrates a schematic diagram illustrating solution architecture to support 5G SNPN charging according to some embodiments of the present disclosure;

Fig. 6 illustrates a schematic diagram illustrating solution architecture to support 5G SNPN charging according to some other embodiments of the present disclosure;

Fig. 7 illustrates a schematic diagram illustrating a method implemented at an access management device in a first network according to some embodiments of the present disclosure;

Fig. 8 illustrates a schematic diagram illustrating a method implemented at a session management device in a first network according to some embodiments of the present disclosure;

Fig. 9 illustrates a schematic diagram illustrating a method implemented at a charging device in a first network according to some embodiments of the present disclosure;

Fig. 10 illustrates a schematic diagram illustrating a method implemented at a first billing device in a first network according to some embodiments of the present disclosure;

Fig. 11 illustrates a schematic diagram illustrating a method implemented at a policy control device in a second network according to some embodiments of the present disclosure;

Fig. 12 illustrates a schematic diagram illustrating a method implemented at a session management device in a second network according to some embodiments of the present disclosure;

Fig. 13 illustrates a schematic diagram illustrating a method implemented at a charging device in a second network according to some embodiments of the present disclosure;

Fig. 14 illustrates a schematic diagram illustrating a method implemented at a second billing device in a second network according to some embodiments of the present disclosure;

Fig. 15 illustrates a simplified block diagram of an apparatus that is suitable for implementing embodiments of the present disclosure; and

Fig. 16 illustrates a block diagram of an example computer readable medium in accordance with some embodiments of the present disclosure;

Throughout the drawings, the same or similar reference numerals represent the same or similar element.

DETAILED DESCRIPTION

Principle of the present disclosure will now be described with reference to some example embodiments. It is to be understood that these embodiments are described only for the purpose of illustration and help those skilled in the art to understand and implement the present disclosure, without suggesting any limitation as to the scope of the disclosure. The disclosure described herein can be implemented in various manners other than the ones described below.

In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skills in the art to which this disclosure belongs.

References in the present disclosure 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 limiting 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 herein, “at least one of the following: <a list of two or more elements>” and “at least one of <a list of two or more elements>” and similar wording, where the list of two or more elements are joined by “and” or “or” , mean at least any one of the elements, or at least any two or more of the elements, or at least all the elements.

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 Long Term Evolution (LTE) , LTE-Advanced (LTE-A) , Wideband Code Division Multiple Access (WCDMA) , High-Speed Packet Access (HSPA) , Narrow Band Internet of Things (NB-IoT) and so on. Furthermore, the communications between a terminal device and a network device in the communication network may be performed according to any suitable generation communication protocols, including, but not limited to, the first generation (1G) , the second generation (2G) , 2.5G, 2.75G, the third generation (3G) , the fourth generation (4G) , 4.5G, the future fifth generation (5G) communication protocols, and/or any other protocols either currently known or to be developed in the future. Embodiments of the present disclosure may be applied in various communication systems. Given the rapid development in communications, there will of course also be future type communication technologies and systems with which the present disclosure may be embodied. It should not be seen as limiting the scope of the present disclosure to only the aforementioned system.

As used herein, the term “network device” refers to a node in a communication network via which a terminal device accesses the network and receives services therefrom. The network device may refer to a base station (BS) or an access point (AP) , for example, a node B (NodeB or NB) , an evolved NodeB (eNodeB or eNB) , a NR NB (also referred to as a gNB) , a Remote Radio Unit (RRU) , a radio header (RH) , a remote radio head (RRH) , a relay, a low power node such as a femto, a pico, and so forth, depending on the applied terminology and technology.

The term “terminal device” refers to any end device that may be capable of wireless communication. By way of example rather than limitation, a terminal device may also be referred to as a communication device, user equipment (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) , an Internet of Things (loT) device, a watch or other wearable, a head-mounted display (HMD) , a vehicle, a drone, a medical device and applications (e.g., remote surgery) , an industrial device and applications (e.g., a robot and/or other wireless devices operating in an industrial and/or an automated processing chain contexts) , a consumer electronics device, a device operating on commercial and/or industrial wireless networks, and the like. In the following description, the terms “terminal device” , “communication device” , “terminal” , “user equipment” and “UE” may be used interchangeably.

Private wireless is a standalone network focused on industrial operational assets and users. Private wireless network provides better privacy, data security, compliance and network performance and well address many mission-critical vertical industrial need.

Non-Public Network is basically the terminology defined by 3GPP for deploying a 5G private network. There are two main deployments defined in 3GPP: Standalone Non-Public Network (SNPN) and Public Network Integrated Non-Public Network (PNI-NPN) .

Now, 3GPP just started to study the charging aspects for enhanced support of non-public network from Rel-18, the latest technical report 3GPP TR 28.828 V0.3.0 (2022-07) is still at draft stage. There are very few topics, use cases, potential requirement and issues documented in this technical report, there is no any solution disclosed how to address kinds of these issues. SNPN charging is a very new and hot work item in 3GPP.

So far, there is no solution of how to support SNPN charging. How to generate revenue and monetize NPN network service is a very important topic for both NPN operator and network operator. More generally, there is no solution for charging a network service provided by an overlay network to a terminal device maintained in an underlay network. The present disclosure provides such a solution, especially for Standalone Non-Public Network (SNPN) charging with underlay/overlay 5G Network.

Principle and embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. Reference is first made to Fig. 1A, which illustrates an example communication system 100 in which embodiments of the present disclosure may be implemented. The system 100 may include a plurality of terminal device 110, as an example, one terminal device 110 is shown in Fig. 1A. The system 100 may also include a core network 130 and a core network 140 (CN for short) , the core network 130 and the core network 140 may be different core networks.

For example, in some embodiments, the core network 130 may be a stand-alone non-public network (SNPN) and the core network 140 may be a public land mobile network (PLMN) . In some other embodiments, the core network 130 may be a PLMN and the core network 140 may be a SNPN. The terminal device 110 may communicate with the core network (CN) 130, for example, the terminal device 110 may communicate with an access management device in the CN 130. The CN 130 and the CN 140 can exchange data via an interface between them. The system 100 may also include a device 120, for example, the device 120 may be a base station 120. The device 120 may communicate with both the terminal device 110 and the CN 130. It is to be understood that the number of devices above is only for the purpose of illustration without suggesting any limitations.

Communications in the communication system 100 may be implemented according to any proper communication protocol (s) , comprising, but not limited to, cellular communication protocols of the first generation (1G) , the second generation (2G) , the third generation (3G) , the fourth generation (4G) and the fifth generation (5G) and on the like, wireless local network communication protocols such as Institute for Electrical and Electronics Engineers (IEEE) 802.11 and the like, and/or any other protocols currently known or to be developed in the future. Moreover, the communication may utilize any proper wireless communication technology, comprising but not limited to: Code Division Multiple Access (CDMA) , Frequency Division Multiple Access (FDMA) , Time Division Multiple Access (TDMA) , Frequency Division Duplex (FDD) , Time Division Duplex (TDD) , Multiple-Input Multiple-Output (MIMO) , Orthogonal Frequency Division Multiple (OFDM) , Discrete Fourier Transform spread OFDM (DFT-s-OFDM) and/or any other technologies currently known or to be developed in the future.

Fig. 1B illustrates a schematic diagram illustrating non-roaming architecture for 5G Core Network with untrusted non-3GPP access. SNPN 5GS deployments are based on the architecture depicted in clause 4.2.3 TS 23.501, the architecture for 5GC with untrusted non-3GPP access, as shown in Fig. 1B for access to SNPN services via a PLMN (and vice versa) . In Fig. 1B, N denotes an interface, for example, N2 denotes an N2 interface, and the like will not be further explained below. To access SNPN services, a UE that has successfully registered with a PLMN over 3GPP access may perform another registration via the PLMN User Plane with an SNPN (using the credentials of that SNPN) . In order to obtain access to Non-Public Network services when the UE is camping in NG-RAN of a PLMN, the UE obtains IP connectivity, discovers and establishes connectivity to an N3IWF in the Stand-alone Non-Public Network. The architecture for access to SNPN services via PLMN is depicted in Fig. 1C, Fig. 1C illustrates a schematic diagram illustrating access to Stand-alone Non-Public Network services via PLMN. To access PLMN services, a UE in SNPN access mode that has successfully registered with an SNPN may perform another registration via the SNPN User Plane with a PLMN (using the credentials of that PLMN) . In order to obtain access to PLMN services when the UE is camping in NG-RAN of Stand-alone Non-Public Network, the UE obtains IP connectivity, discovers and establishes connectivity to an N3IWF in the PLMN. The architecture for access to PLMN services via SNPN is depicted in Fig. 1D, Fig. 1D illustrates a schematic diagram illustrating access to PLMN services via Stand-alone Non-Public Network.

In the deployment architecture in Fig. 1C, the SNPN is the overlay network and the PLMN is the underlay network. N3IWF in SNPN network segregates and hides underlay PLMN network, and currently, there is no way for SNPN overlay network to obtain the underlay network charging information (or called as access information) to implement UE charging in SNPN based on access network information of PLMN network, there is no way to correlate the charging data generated in PLMN network and charging data generated in SNPN network to correctly implement inter-operator charging or settlement between PLMN operator and SNPN operator for a UE who has a subscription with the PLMN which allows access of the SNPN service.

In the deployment architecture in Fig. 1D, the PLMN is the overlay network and the SNPN is the underlay network. N3IWF in PLMN network segregates and hides underlay SNPN network, similarly as above deployment of Fig. 1D, there is no way for PLMN overlay network to obtain the underlay network charging information to implement UE charging in PLMN based on access network information of SNPN network, there is no way to correlate the charging data generated in SNPN network and charging data generated in PLMN network to correctly implement inter-operator charging or settlement between SNPN operator and PLMN operator for a UE who has a subscription with the SNPN which allows access of the PLMN service.

Fig. 2 illustrates a call flow diagram 200 according to some embodiments of the present disclosure. As shown in Fig. 2, in the first network, an access management device 250 in a first network may transmit (2110) , to a policy control device 220 in a second network via an interface between the access management device and the policy control device, a request 2005 for access information 2015 of a terminal device 110 maintained in the second network for charging for a packet data unit (PDU) session of the terminal device 110. The terminal device 110 is not shown in Fig. 2.

In the second network, the policy control device 220 in the second network may receive (2120) , from the access management device 250 in the first network via the interface, the request 2005 for the access information 2015 of the terminal device 110 maintained in the second network for charging for the PDU session of the terminal device 110. The PDU session being established in the first network via the second network. The policy control device 220 in the second network may transmit (2130) the access information 2015 of the terminal device 110 maintained in the second network to the access management device 250 in the first network via the interface.

In the first network, the access management device 250 in the first network may receive (2140) the access information 2015 of the terminal device 110 in the second network from the policy control device 220 in the second network via the interface. In this way, the first network may obtain the access information from the second network.

In the first network, the access management device 250 in the first network may transmit (2150) the access information 2015 of the terminal device 110 in the second network to the session management device 260 in the first network. The session management device 260 in the first network may receive (2160) , from the access management device 250 in the first network, the access information 2015 of a terminal device 110 maintained in the second network for charging for the PDU session of the terminal device 110, and transmit (2170) , to a charging device 270 in the first network, the charging request 2025. The charging request 2025 may comprise but not limited to the access information 2015 of the terminal device 110 in the second network, in other word, the charging request 2025 may comprise other information. The access information 2015 is for charging for the PDU session of the terminal device 110. The charging device 270 in the first network may receive (2180) from the session management device 260 in the first network, the charging request 2025. The charging device 270 in the first network may generate (2190) a charging data record (CDR) (i.e. a first CDR 2035) in the first network for the PDU session based on the access information 2015 of the terminal device 110 in the second network, and transmit (2200) the CDR 2035 in the first network to a billing device (i.e. a first billing device) 280 in the first network. The first billing device 280 may receive (2210) , from the charging device 270 in the first network, the first CDR 2035 in the first network for the PDU session of the terminal device 110. In this way, the first network implement the terminal device 110 charging based on the access information 2015 obtained from the second network. After the step 2190, the charging device 270 in the first network may also respond a charging response message to the session management device 260 in the first network (this step is not shown in Fig. 2) .

In the second network, a session management device 210 in the second network may receive (2220) , at from the policy control device 220 in the second network, charging correlation information 2045 for the PDU session of the terminal device 110, and transmit (2230) , to a charging device 230 in the second network device, a charging request 2055, and the charging request 2055 comprises but not limited to the charging correlation information 2045 for the PDU session of a terminal device 110. The charging correlation information 2045 will be further described below. The charging device 230 in the second network may receive (2240) , from the session management device 210 in the second network, the charging request 2055 comprising charging correlation information 2045, and generate (2250) a charging data record (CDR) (i.e. a second CDR 2065) in the second network for the PDU session based on the charging correlation information 2045; and transmit (2260) the CDR 2065 in the second network to a billing device (i.e. a second billing device) 240 in the second network. In the second network, the second billing device 240 in a second network may receive (2270) , from the charging device 230 in the second network, the CDR 2065 in the second network for the PDU session of the terminal device 110, and transmit (2280) the CDR 2065 to the first billing device 280 in the first network.

Accordingly, in the first network, the first billing device 280 in the first network may receive (2290) , from the second billing device 240 in the second network, the CDR 2065 (second CDR) in the second network for the PDU session and correlate (2300) the first CDR 2035 and the second CDR 2065.

In this way, charging data generated in the first network and charging data generated in the second network may be correlated to correctly implement inter-operator charging or settlement between the first network operator and the second network operator for the terminal device 110 who has a subscription with the second network which allows access of the first network service.

In some embodiments, the first network is a public land mobile network (PLMN) and the second network is a stand-alone non-public network (SNPN) . In some other embodiments, the first network is a SNPN and the second network is a PLMN.

In some embodiments, the access information 2015 may comprise at least one of the following: an identification of charging for the PDU session of the second network, an identification of the second network, a location of the terminal device 110, or an access technology of the terminal device 110.

In some embodiments, the session management device 260 in the first network may generate charging correlation information 2045 for charging for the PDU session in the first network, and transmit the charging correlation information 2045 to the access management device 250 in the first network. Specifically, the session management device 260 in the first network may generate the charging correlation information 2045 after receiving the charging response message indicating a successful response from the charging device 270 in the first network.

Accordingly, the access management device 250 in the first network may receive, from the session management device 260 in the first network, the charging correlation information 2045 for the PDU session in the first network, and transmit the charging correlation information 2045 to the policy control device 220 in the second network via the interface between the access management device 250 and the policy control device 220. The policy control device 220 in the second network may receive, from the access management device 250 in the first network via the interface, the charging correlation information 2045 for the PDU session in the first network, and transmit the charging correlation information 2045 to the session management device 210 in the second network device.

In some embodiments, the CDR 2065 in the second network may comprise the charging correlation information 2045, such that the charging correlation information 2045 from the first network can be used for correlating the first CDR 2035 and the second CDR 2065.

In some embodiments, the interface may be protected via a security edge protection proxy (SEPP) . In this way, the new interface above provided by the embodiments of the present disclosure can be protected via the SEPP, and can exchange policy and charging information of underlay and overlay information between PCF (an example of the policy control device 220 or implemented in the policy control device 220) in underlay network (an example of the second network) and AMF (an example of the access management device 250 or implemented in the access management device 250) in overlay network (an example of the first network) .

In some embodiments, the charging correlation information 2045 may comprise at least one of the following: an identification of charging for the PDU session allocated by the session management device 260, an address of the session management device 260 in the first network, or an identification of the first network.

In some embodiments, the charging device 230 may generate the CDR 2065 in the second network by performing inter-operator charging based on a wholesale tariff of a provider of the first network for the terminal device 110 for the PDU session.

In some embodiments, the first network may be an overlay network, for example the CN 140. The second network may be an underlay network, for example the CN 130. In some embodiments, the overlay network may comprise AMF, SMF, CHF and Billing system, etc. The underlay network may comprise PCF, SMF, CHF and Billing system, etc.

When UE (an example of the terminal device 110) tries to create a PDU session in the overlay network, the AMF in the overlay network will invoke a request to the PCF in the underlay network to obtain underlay access network charging information (also called as access information, e.g. PLMN ID + Network ID, user location information, access technologies, etc. ) maintained in the PCF of the underlay network via the newly introduced interface, the AMF then passes the underlay access network charging information in the PDU session create request to the SMF (session management function) of the overlay network.

In some embodiments, when the SMF in the overlay network sends the PDU session create response message to the AMF, the response message will include the overlay network charging correlation information (e.g. PDU Session charging ID allocated by SMF, SMF address of overlay network, PLMN ID + Network ID (PLMN +Network ID which will identify SNPS network) ) . The AMF will notify or update the PCF of the underlay network about the overlay network charging correlation information, which are further passed to the SMF of the underlay network by the PCF.

In some embodiments, when the SMF in the overlay network generates the charging data request (also called as charging request) to overlay CHF (charging function) , the charging data request metered by the overlay network reports the service usage of the overlay network, the charging data request will additionally include the underlay access network information (such as user location, radio access technology) . In this way, the CHF in the overlay network will correctly charge the network service data and perform charging service control based on access network information of the underlay network.

In some embodiments, when the SMF in the underlay network generates the charging data request to the CHF in the underlay network, the charging data request metered by the underlay network reports the service usage of the overlay network via the underlay network per UE. Besides the normal charging from the SMF to the CHF, the SMF shall additionally include overlay network charging correlation information (e.g. the PDU Session Charging ID, SMF address of overlay network, PLMN ID Network ID of SNPN + Network ID) . The CDR (charging data record) generated by the CHF of the underlay network shall also reflect this kind of the overlay network charging correlation information. In this way, the embodiments of the present disclosure will enable inter-operator charging and settlement (between underlay network operator and overlay network operator) , the underlay CHF performs wholesale charging per UE and per overlay network service over underlay network. The embodiments of the present disclosure will also enable the overlay network operator to correlate CDR received from the underlay network provider to the CDR generated in the overlay network, enable correctly implement revenue assurance and settlement, and avoid the over-revenue collection from the underlay network provider.

Fig. 3 illustrates a call flow diagram 300 according to some other embodiments of the present disclosure. Fig. 4 illustrates a call flow diagram 400 according to some other embodiments of the present disclosure. With reference to Fig. 3 and Fig. 4 and the embodiments of the present disclosure mentioned above, the overlay network is an example of the first network, and the underlay network is an example of the second network. In overlay network. The AMF 306 in the overlay network is an example of the access management device in the first network. The SMF 307 in the overlay network is an example of the session management device in the first network. The CHF 308 in the overlay network is an example of the charging device in the first network. The Billing system 309 in the overlay network is an example of the first billing device in the first network. The PCF 303 in the underlay network is an example of the policy control device in the second network. The SMF 302 in the underlay network is an example of the session management device in the second network. The CHF 304 in the underlay network is an example of the charging device in the second network. The Billing system 305 in the underlay network is an example of the second billing device in the second network. The UE 301 is an example of the terminal device 110.

As shown in Fig. 3, the CHF 308 in the overlay network by utilizing to the underlay network access information to charge the UE’s 301 traffic to the overlay network via the underlay network. The UE 301 requests PDU Session Establishment/Modification via N3IWF (non 3gpp InterWork Function) to the AMF 306 in the overlay network (310) . The AMF 306 of the overlay network retrieves the UE's 301 underlay network access information (PLMN ID, NID, UE 301 location and access technology, etc. ) maintained in the PCF 303 of the underlay network (320) . The AMF 306 of the overlay network pass the UE's 301 underlay network access information in Nsmf_PDUSession_Create (Update) SMContext Request to the SMF 307 of the overlay network (330) . The underlay network access information in charging data request (or called as charging request) message is reported to the CHF 308 of the overlay network by the SMF 307 of the overlay network when charging report is triggered (340) . The CHF 308 of the overlay network performs data charging for the UE's 301 traffic (i.e. charging for PDU session of the terminal device 110) based on the underlay network access information (350) . The CHF 308 may transmit, to the billing system 309 in the overlay network, the CDR/Rated CDR (in the overlay network) including the underlay network access information (360) .

As shown in Fig. 4, the CHF 304 in the underlay network by including the overlay network charging correlation information for inter-operator charging between underlay network provider and overlay network provider. The SMF 307 in the overlay network is ready to establish PDU session, and allocate charging ID for PDU session (410) . The charging ID for PDU session is an example of an identification of charging for the PDU session allocated by the session management device. The SMF 307 in the overlay network includes charging ID, SMF ID, PLMN ID and NID in Nsmf_Communication_N1N2MessageTransfer message to the AMF 306 of the overlay network (420) . The AMF 306 of the overlay network notify/updates the PCF 303 in the underlay network about overlay network charging correlation information (charging ID, SMF ID, PLMN ID and NID) (430) . The PCF 303 in the underlay network updates the overlay network charging correlation information into the underlay network SMF 302 own PDU session context (440) . When the SMF 302 in the underlay network generates charging request to the CHF 304 in the underlay network, and the overlay network charging correlation information in the charging data request (i.e. charging request) will be sent to the CHF 304 in the underlay network (450) . The CHF 304 in the underlay network performs wholesale charging based on the overlay network provider's tariff to charge the UE's traffic via the underlay network to the overlay network data network (i.e. the overlay network) (460) . The CHF 304 may transmit, to the billing system 305 in the underlay network, the CDR/Rated CDR includes the overlay network charging correlation information (470) . The invoice and rated CDR including the overlay network charging correlation information from the underlay network provider to the overlay network provider to revenue collection (480) .

Fig. 5 illustrates a schematic diagram illustrating solution architecture to support 5G SNPN charging according to some embodiments of the present disclosure. As shown in Fig. 5, SNPN CN is the underlay network and PLMN CN is the overlay network. The UE traffic for PLMN data connection is over SNPN underlay network.

SMF in SNPN CN reports the data charging request to SNPN CHF about UE’s traffic for data connectivity to NPN service. The charged party is UE subscriber, the charging party is SNPN provider.

SMF in PLMN CN will report the data charging request to PLMN CHF about UE’s traffic for data connectivity to PLMN data service via NPN. The charged party is UE subscriber, the charging party is PLMN provider.

SMF in SNPN CN will also report data charging request to SNPN CHF about UE’s traffic for data connectivity to PLMN data service via NPN. The charged party is PLMN provider, the charging party is SNPN provider.

The embodiments of the present disclosure enable the CHF in PLMN CN to charge UE’s service data flow per PDU session by using the underlay network access information for UE traffic to the PLMN DN (Data Network) via NPN underlay network. The Fig. 5 shows the enhancement of the related interface to enable the AMF in the PLMN CN to query access network information maintained in the PCF in the NPN CN. The AMF in the PLMN CN then transfers the underlay network access charging information to the SMF in the PLMN CN, which further includes the underlay network access information into the data charging request to the CHF in the PLMN CN.

In some embodiments, the detail steps are as the following: S1, when the UE requests PDU Session Establishment/Modification via N3IWF to the AMF in the PLMN CN, the AMF in the PLMN CN will send a request to the PCF in the underlay NPN CN to query UE’s user location, access technologies + PLMNID/NID etc., access network information via the newly introduced interface. The PCF in the underlay NPN CN will return UE’s underlay access network information to the AMF in the overlay network. S2, the AMF in the overlay network will include the UE’s access network information in Nsmf_PDUSession_CreateSMContext Request/Update CreateSMContext request and sends the message to the SMF in the PLMN CN. S3, the SMF in the PLMN CN will send data charging request (with the underlay network access information) to the CHF in the PLMN CN, so the CHF in the PLMN CN will enable to charge UE’s data traffic transferred over the underlay NPN network by utilizing the underlay network access information.

The embodiments of the present disclosure enable the SNPN CHF to perform inter-operator charging based on the PLMN’s wholesale tariff to charge and rate each UE’s traffic over the NPN underlay network to the PLMN DN. Fig. 5 shows the enhancement of the related interface to support the AMF in the PLMN overlay network to pass the PDU Session Charging ID+SMF ID + PLMN ID to the SMF in the NPN underlay network via the PCF in underlay network with the newly introduced interface. S4, when the PDU session is ready to establish in the PLMN CN, the SMF in the PLMN CN will generate the PDU Session Charging ID for the UE’s PDU session in the PLMN. The SMF will return Charging ID+SMF ID+ PLMN ID to AMF in Nsmf_Communication_N1N2MessageTransfer message. S5, the AMF will notify/update the overlay network charging correlation information (PDU session Charging ID+SMF ID+ PLMN ID) to the PCF in the NPN CN via the newly introduced interface. S6, the PCF in the NPN will further update the overlay network charging correlation information to the SMF in the NPN. S7, when the UE has data connectivity to the PLMN service via the NPN underlay network. The SMF in the underlay NPN will report data charging request (including overlay network charging correlation information: PDU Session Charging ID+SMF ID+ PLMN ID) to the CHF in the NPN CN, so the CHF in the NPN CN will enable to perform inter-operator charging based on PLMN ID’s wholesale tariff per UE per service data flow over the NPN underlay network. S8, the NPN billing system will send the rated CDR to the PLMN for revenue collection. S9, with the overlay network/PLMN charging correlation information (i.e. overlay network PDU Session Charging ID+SMF ID+ PLMN ID) in rated CDR from NPN provider, the PLMN billing system can correlate CDR from the NPN provider to the CDR generated by the PLMN CHF for revenue assurance and avoid over-charge from the NPN provider.

Fig. 6 illustrates a schematic diagram illustrating solution architecture to support 5G SNPN charging according to some other embodiments of the present disclosure. As shown in Fig. 6, the PLMN CN is an underlay network and the NPN CN is an overlay network. The UE traffic for the NPN data connection is over the PLMN underlay network. the SMF in the PLMN CN reports the data charging request to the PLMN CHF about UE’s traffic for data connectivity to the PLMN service. The charged party is UE subscriber, the charging party is the PLMN provider.

The SMF in the NPN CN will report the data charging request to the NPN CHF about UE’s traffic for data connectivity to the NPN data service via the PLMN CN. The charged party is UE subscriber, the charging party is the NPN provider.

SMF in the PLMN CN will also report data charging request to the PLMN CHF about UE’s traffic for data connectivity to the NPN data service via the PLMN CN. The charged party is the NPN provider, the charging party is the PLMN provider.

The embodiments of the present disclosure enable the CHF in the NPN CN to charge UE’s service data flow per PDU session by using the underlay network access info for UE traffic to the NPN DN (Data Network) via underlay the PLMN network. The Fig. 6 shows the enhancement of the related interface to enable the AMF in the NPN CN to query access network information maintained in the PCF in the PLMN CN. The AMF in the NPN CN then transfers the underlay network access charging information to the SMF in the NPN CN, which further includes the underlay network access information into the data charging request to CHF in the NPN CN. The detail steps are as the following: S1, when the UE requests the PDU Session Establishment/Modification via N3IWF to the AMF in the NPN CN, the AMF will send a request to the PCF in the underlay PLMN CN to query the UE’s user location, access technologies + PLMNID etc., access network information via the newly introduced interface. The PCF will return UE’s underlay access network information to the AMF. S2, the AMF will include the UE’s access network information in Nsmf_PDUSession_CreateSMContext Request/Update request and sends the message to SMF in NPN CN. S3, the SMF in the NPN CN will send data charging request (with underlay network access information) to the CHF in the NPN CN, so the CHF in the NPN CN will enable to charge the UE’s data traffic transferred over the underlay PLMN network by utilizing underlay network access information.

The embodiments of the present enable the PLMN CHF to perform inter-operator charging based on the NPN’s wholesale tariff to charge and rate each the UE’s traffic over underlay PLMN network to the NPN DN. Fig. 6 shows the enhancement of the related interface to support the AMF in the NPN CN to pass overlay network charging correction information (PDU Session Charging ID+SMF ID + PLMN ID + NID) to PCF in PLMN CN via the newly introduced interface. S4, when the PDU session is ready to establish in the NPN CN, the SMF in the NPN CN will generate the PDU Session Charging ID for the UE’s PDU session in the NPN. The SMF will include Charging ID+SMF ID+ PLMN ID + NID in Nsmf_Communication_N1N2MessageTransfer message to the AMF. S5, the AMF will notify/update the overlay network charging correlation information (PDU session Charging ID+SMF ID+ PLMN ID +NID) the PCF in the PLMN CN via the newly introduced interface. S6, the PCF in the PLMN will further update overlay network charging correlation info to the SMF in PLMN. S7, when UE has data connectivity to the NPN service via the PLMN underlay network. The SMF in the underlay PLMN network will report data charging request (including overlay network charging correlation information: PDU Session Charging ID+SMF ID+ PLMN ID+NID) to the PLMN CHF, so the CHF in the PLMN CN will enable to perform inter-operator charging based on NPN provider’s wholesale tariff per UE per service data flow over the PLMN underlay network. S8, PLMN billing system will send the rated CDR to the NPN for revenue collection. S9, with the overlay network/NPN CN charging correlation information (i.e. overlay network PDU Session Charging ID+SMF ID+ PLMN ID+NID) in rated CDR from PLMN provider, NPN billing system can correlate the CDR from the PLMN provider to the CDR generated by the NPN CHF for revenue assurance and avoid over-charge from the PLMN provider.

Fig. 7 illustrates a schematic diagram illustrating a method 700 implemented at an access management device in a first network according to some other embodiments of the present disclosure. At block 710, the access management device may transmit, to a policy control device in a second network via an interface between the access management device and the policy control device, a request for access information of a terminal device 110 maintained in the second network for charging for a packet data unit (PDU) session of the terminal device 110. The PDU session is established in the first network via the second network. At block 720, the access management device may receive the access information of the terminal device 110 in the second network from the policy control device in the second network via the interface. At block 730, the access management device may transmit the access information of the terminal device 110 in the second network to a session management device in the first network.

In some embodiments, the access information comprises at least one of the following: an identification of charging for the PDU session of the second network (i.e. a PDU session charging ID of the second network) , an identification of the second network, a location of the terminal device 110, or an access technology of the terminal device 110.

In some embodiments, the access management device may receive, from the session management device in the first network, charging correlation information for the PDU session in the first network; and transmit the charging correlation information to the policy control device in the second network via the interface.

In some embodiments, the interface is protected via a security edge protection proxy (SEPP) .

Fig. 8 illustrates a schematic diagram illustrating a method 800 implemented at a session management device in a first network according to some other embodiments of the present disclosure. At block 810, the session management device in a first network may receive, from an access management device in the first network, access information of a terminal device 110 maintained in a second network for charging for a packet data unit (PDU) session of the terminal device 110. The PDU session being established in the first network via the second network. At block 820, the session management device in a first network may transmit, to a charging device in the first network, a charging request comprising the access information of the terminal device 110 in the second network.

In some embodiments, the session management device may generate charging correlation information for charging for the PDU session in the first network; and transmit the charging correlation information to the access management device in the first network.

In some embodiments, the charging correlation information comprises at least one of the following: an identification of charging for the PDU session allocated by the session management device, an address of the session management device in the first network, or an identification of the first network.

Fig. 9 illustrates a schematic diagram illustrating a method 900 implemented at a charging device in a first network according to some other embodiments of the present disclosure. At block 910, the charging device in the first network may receive, from a session management device in the first network, a charging request comprising access information of a terminal device 110 maintained in a second network. The access information is for charging for a packet data unit (PDU) session of the terminal device 110, and the PDU session is established in the first network via the second network. At block 920, the charging device in the first network may generate a charging data record (CDR) in the first network for the PDU session based on the access information of the terminal device 110 in the second network. At block 930, the charging device in the first network may transmit the CDR in the first network to a billing device in the first network.

Fig. 10 illustrates a schematic diagram illustrating a method 1000 implemented at a first billing device in a first network according to some other embodiments of the present disclosure. At block 1010, the first billing device may receive, from a charging device in the first network, a first charging data record (CDR) in the first network for a packet data unit (PDU) session of a terminal device 110. The PDU session may be established in the first network via a second network. At block 1020, the first billing device may receive, from a second billing device in the second network, a second CDR in the second network for the PDU session. At block 1030, the first billing device may correlate the first CDR and the second CDR.

Fig. 11 illustrates a schematic diagram illustrating a method 1100 implemented at a policy control device in a second network according to some other embodiments of the present disclosure. At block 1110, the policy control device may receive, from an access management device in a first network via an interface between the access management device and the policy control device, a request for access information of a terminal device 110 maintained in the second network for charging for a packet data unit (PDU) session of the terminal device 110, the PDU session being established in the first network via the second network. At block 1120, the policy control device may transmit the access information of the terminal device 110 in the second network to the access management device in the first network via the interface.

In some embodiments, the policy control device may receive, from the access management device in the first network via the interface, charging correlation information for the PDU session in the first network; and transmit the charging correlation information to a session management device in the second network device.

Fig. 12 illustrates a schematic diagram illustrating a method 1200 implemented at a session management device in a second network according to some other embodiments of the present disclosure. At block 1210, the session management device may receive, from a policy control device in the second network, charging correlation information for a packet data unit (PDU) session of a terminal device 110, the PDU session being established in a first network via the second network. At block 1220, the session management device may transmit, to a charging device in the second network device, a charging request comprising the charging correlation information.

In some embodiments, the charging correlation information comprises at least one of the following: an identification of charging for the PDU session allocated by a session management device in the first network, an address of the session management device in the first network, or an identification of the first network.

Fig. 13 illustrates a schematic diagram illustrating a method 1300 implemented at a charging device in a second network according to some other embodiments of the present disclosure. At block 1310, the charging device in the second network may receive, from a session management device in the second network, a charging request comprising charging correlation information for a packet data unit (PDU) session of a terminal device 110, the PDU session being established in a first network via the second network. At block 1320, the charging device in the second network may generate a charging data record (CDR) in the second network for the PDU session based on the charging correlation information. At block 1330, the charging device in the second network may transmit the CDR in the second network to a billing device in the second network.

In some embodiments, the charging device may generate the CDR in the second network by: performing inter-operator charging based on a wholesale tariff of a provider of the first network for the terminal device 110 for the PDU session.

In some embodiments, the CDR in the second network comprises the charging correlation information.

Fig. 14 illustrates a schematic diagram illustrating a method 1400 implemented at a second billing device in a second network according to some other embodiments of the present disclosure. At block 1410, the second billing device in the second network may receive, from a charging device in the second network, a charging data record (CDR) in the second network for a packet data unit (PDU) session of a terminal device 110, the PDU session being established in a first network via a second network. At block 1420, the second billing device in the second network may transmit the CDR to a first billing device in the first network.

In some embodiments, an apparatus capable of performing any of the method 700 (for example, an access management device in a first network (the core network 140 may be an example of the first network) ) may comprise means for performing the respective steps of the method 700. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

In some embodiments, the apparatus comprises means for transmitting, at an access management device in a first network, to a policy control device in a second network via an interface between the access management device and the policy control device, a request for access information of a terminal device 110 maintained in the second network for charging for a packet data unit (PDU) session of the terminal device 110, the PDU session being established in the first network via the second network; means for receiving the access information of the terminal device 110 in the second network from the policy control device in the second network via the interface; and means for transmitting the access information of the terminal device 110 in the second network to a session management device in the first network.

In some embodiments, the first network is a public land mobile network (PLMN) and the second network is a stand-alone non-public network (SNPN) , or the first network is a SNPN and the second network is a PLMN.

In some embodiments, the access information comprises at least one of the following: an identification of a PDU session charging (i.e. a PDU session charging ID) of the second network, an identification of the second network, a location of the terminal device 110, or an access technology of the terminal device 110.

In some embodiments, the access management device further comprises means for receiving, from the session management device in the first network, charging correlation information for the PDU session in the first network; and means for transmitting the charging correlation information to the policy control device in the second network via the interface.

In some embodiments, the apparatus further comprises means for performing other steps in some embodiments of the method 700. In some embodiments, the means comprises at least one processor and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the performance of the apparatus.

In some embodiments, an apparatus capable of performing any of the method 800 (for example, a session management device in the core network 140) may comprise means for performing the respective steps of the method 800. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

In some embodiments, the apparatus comprises means for receiving, at a session management device in a first network from an access management device in the first network, access information of a terminal device 110 maintained in a second network for charging for a packet data unit (PDU) session of the terminal device 110, the PDU session being established in the first network via the second network; and means for transmitting, to a charging device in the first network, a charging request comprising the access information of the terminal device 110 in the second network.

In some embodiments, the session management device further comprises means for generating charging correlation information for charging for the PDU session in the first network; and means for transmitting the charging correlation information to the access management device in the first network.

In some embodiments, the first network is a public land mobile network (PLMN) and the second network is a stand-alone non-public network (SNPN) ; or the first network is a SNPN and the second network is a PLMN.

In some embodiments, the apparatus further comprises means for performing other steps in some embodiments of the method 800. In some embodiments, the means comprises at least one processor and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the performance of the apparatus.

In some embodiments, an apparatus capable of performing any of the method 900 (for example, a charging device in the core network 140) may comprise means for performing the respective steps of the method 900. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

In some embodiments, the apparatus comprises means for receiving, at a charging device in a first network from a session management device in the first network, a charging request comprising access information of a terminal device 110 maintained in a second network, the access information being for charging for a packet data unit (PDU) session of the terminal device 110, the PDU session being established in the first network via the second network; means for generating a charging data record (CDR) in the first network for the PDU session based on the access information of the terminal device 110 in the second network; and means for transmitting the CDR in the first network to a billing device in the first network.

In some embodiments, the apparatus further comprises means for performing other steps in some embodiments of the method 900. In some embodiments, the means comprises at least one processor and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the performance of the apparatus.

In some embodiments, an apparatus capable of performing any of the method 1000 (for example, a first billing device in the core network 140) may comprise means for performing the respective steps of the method 1000. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

In some embodiments, the apparatus comprises means for receiving, at a first billing device in a first network from a charging device in the first network, a first charging data record (CDR) in the first network for a packet data unit (PDU) session of a terminal device 110, the PDU session being established in the first network via a second network; means for receiving, from a second billing device in the second network, a second CDR in the second network for the PDU session; and means for correlating the first CDR and the second CDR.

In some embodiments, the apparatus further comprises means for performing other steps in some embodiments of the method 1000. In some embodiments, the means comprises at least one processor and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the performance of the apparatus.

In some embodiments, an apparatus capable of performing any of the method 1100 (for example, a policy control device in a second network (the core network 130 may be an example of the second network) may comprise means for performing the respective steps of the method 1100. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

In some embodiments, the apparatus comprises means for receiving, at a policy control device in the second network from an access management device in a first network via an interface between the access management device and the policy control device, a request for access information of a terminal device 110 maintained in the second network for charging for a packet data unit (PDU) session of the terminal device 110, the PDU session being established in the first network via the second network; and means for transmitting the access information of the terminal device 110 in the second network to the access management device in the first network via the interface.

In some embodiments, the policy control device further comprises means for receiving, from the access management device in the first network via the interface, charging correlation information for the PDU session in the first network; and means for transmitting the charging correlation information to a session management device in the second network device.

In some embodiments, the apparatus further comprises means for performing other steps in some embodiments of the method 1100. In some embodiments, the means comprises at least one processor and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the performance of the apparatus.

In some embodiments, an apparatus capable of performing any of the method 1200 (for example, a session management device in the core network 130) may comprise means for performing the respective steps of the method 1200. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

In some embodiments, the apparatus comprises means for receiving, at a session management device in a second network from a policy control device in the second network, charging correlation information for a packet data unit (PDU) session of a terminal device 110, the PDU session being established in a first network via the second network; and means for transmitting, to a charging device in the second network device, a charging request comprising the charging correlation information.

In some embodiments, the apparatus further comprises means for performing other steps in some embodiments of the method 1200. In some embodiments, the means comprises at least one processor and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the performance of the apparatus.

In some embodiments, an apparatus capable of performing any of the method 1300 (for example, a charging device in the core network 130) may comprise means for performing the respective steps of the method 1300. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

In some embodiments, the apparatus comprises means for receiving, at a charging device in a second network from a session management device in the second network, a charging request comprising charging correlation information for a packet data unit (PDU) session of a terminal device 110, the PDU session being established in a first network via the second network; means for generating a charging data record (CDR) in the second network for the PDU session based on the charging correlation information; and means for transmitting the CDR in the second network to a billing device in the second network.

In some embodiments, means for generating the CDR in the second network comprises means for performing inter-operator charging based on a wholesale tariff of a provider of the first network for the terminal device 110 for the PDU session.

In some embodiments, the apparatus further comprises means for performing other steps in some embodiments of the method 1300. In some embodiments, the means comprises at least one processor and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the performance of the apparatus.

In some embodiments, an apparatus capable of performing any of the method 1400 (for example, a second billing device in the core network 130) may comprise means for performing the respective steps of the method 1400. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

In some embodiments, the apparatus comprises means for receiving, at a second billing device in a second network from a charging device in the second network, a charging data record (CDR) in the second network for a packet data unit (PDU) session of a terminal device 110, the PDU session being established in a first network via a second network; and means for transmitting the CDR to a first billing device in the first network.

In some embodiments, the apparatus further comprises means for performing other steps in some embodiments of the method 1400. In some embodiments, the means comprises at least one processor and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the performance of the apparatus.

FIG. 15 is a simplified block diagram of a device 1500 that is suitable for implementing embodiments of the present disclosure. The device 1500 may be provided to implement the communication device, for example the device in the core network 130 or the core network 140, the core network 130 or the core network 140 as shown in Fig. 1A. As shown, the device 1500 includes one or more processors 1510, one or more memories 1540 coupled to the processor 1510, and one or more transmitters and/or receivers (TX/RX) 1540 coupled to the processor 1510.

The TX/RX 1540 is for bidirectional communications. The TX/RX 1540 has at least one antenna to facilitate communication. The communication interface may represent any interface that is necessary for communication with other network elements.

The processor 1510 may be of any type suitable to the local technical network and may include one or more of the following: general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device 1500 may have multiple processors, such as an application specific integrated circuit chip that is slaved in time to a clock which synchronizes the main processor.

The memory 1520 may include one or more non-volatile memories and one or more volatile memories. Examples of the non-volatile memories include, but are not limited to, a Read Only Memory (ROM) 1524, an electrically programmable read only memory (EPROM) , a flash memory, a hard disk, a compact disc (CD) , a digital video disk (DVD) , and other magnetic storage and/or optical storage. Examples of the volatile memories include, but are not limited to, a random access memory (RAM) 1522 and other volatile memories that will not last in the power-down duration.

A computer program 1530 includes computer executable instructions that are executed by the associated processor 1510. The program 1530 may be stored in the ROM 1524. The processor 1510 may perform any suitable actions and processing by loading the program 1530 into the RAM 1522.

The embodiments of the present disclosure may be implemented by means of the program 1530 so that the device 1500 may perform any process of the disclosure as discussed with reference to Figs. 2 to 14. The embodiments of the present disclosure may also be implemented by hardware or by a combination of software and hardware.

In some embodiments, the program 1530 may be tangibly contained in a computer readable medium which may be included in the device 1500 (such as in the memory 1520) or other storage devices that are accessible by the device 1500. The device 1500 may load the program 1530 from the computer readable medium to the RAM 1522 for execution. The computer readable medium may include any types of tangible non-volatile storage, such as ROM, EPROM, a flash memory, a hard disk, CD, DVD, and the like. Fig. 16 shows an example of the computer readable medium 1600 in form of CD or DVD. The computer readable medium has the program 1530 stored thereon.

Generally, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. While various aspects of embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representations, it is to be understood that the block, apparatus, system, technique or method described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer readable storage medium. The computer program product includes computer-executable instructions, such as those included in program modules, being executed in a device on a target real or virtual processor, to carry out the method 700 to 1400 as described above with reference to Figs 2-14. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.

Program code for carrying out methods of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program codes, when executed by the processor or controller, cause the functions/operations specified in the flowcharts and/or block diagrams to be implemented. The program code may execute entirely on a machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.

In the context of the present disclosure, the computer program codes or related data may be carried by any suitable carrier to enable the device, apparatus or processor to perform various processes and operations as described above. Examples of the carrier include a signal, computer readable medium, and the like.

The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable medium may include but not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the computer readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM) , a read-only memory (ROM) , an erasable programmable read-only memory (EPROM or Flash memory) , an optical fiber, a portable compact disc read-only memory (CD-ROM) , an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. The term “non-transitory, ” as used herein, is a limitation of the medium itself (i.e., tangible, not a signal) as opposed to a limitation on data storage persistency (e.g., RAM vs. ROM) .

Further, while operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Likewise, while several specific implementation details are contained in the above discussions, these should not be construed as limitations on the scope of the present disclosure, but rather as descriptions of features that may be specific to particular embodiments. Certain features that are described 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 may also be implemented in multiple embodiments separately or in any suitable sub-combination.

Although the present disclosure has been described in languages specific to structural features and/or methodological acts, it is to be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

An access management device in a first network, comprising:

at least one processor; and

at least one memory storing instructions that, when executed by the at least one processor, cause the access management device at least to:

transmit, to a policy control device in a second network via an interface between the access management device and the policy control device, a request for access information of a maintained in the second network for charging for a packet data unit (PDU) session of the terminal device, the PDU session being established in the first network via the second network;

receive the access information of the terminal device in the second network from the policy control device in the second network via the interface; and

transmit the access information of the terminal device in the second network to a session management device in the first network.
The access management device of claim 1, wherein:

the first network is a public land mobile network (PLMN) and the second network is a stand-alone non-public network (SNPN) ; or

the first network is a SNPN and the second network is a PLMN.
The access management device of claim 1 or 2, wherein the access information comprises at least one of the following:

an identification of charging for the PDU session of the second network,

an identification of the second network,

a location of the terminal device, or

an access technology of the terminal device.
The access management device of any of claims 1-3, wherein the access management device is further caused to:

receive, from the session management device in the first network, charging correlation information for the PDU session in the first network; and

transmit the charging correlation information to the policy control device in the second network via the interface.
The access management device of any of claims 1-4, wherein the interface is protected via a security edge protection proxy (SEPP) .
A session management device in a first network, comprising:

at least one processor; and

at least one memory storing instructions that, when executed by the at least one processor, cause the session management device at least to:

receive, from an access management device in the first network, access information of a terminal device maintained in a second network for charging for a packet data unit (PDU) session of the terminal device, the PDU session being established in the first network via the second network; and

transmit, to a charging device in the first network, a charging request comprising the access information of the terminal device in the second network.
The session management device of claim 6, wherein the session management device is further caused to:

generate charging correlation information for charging for the PDU session in the first network; and

transmit the charging correlation information to the access management device in the first network.
The session management device of claim 6 or 7, wherein:

the first network is a public land mobile network (PLMN) and the second network is a stand-alone non-public network (SNPN) ; or

the first network is a SNPN and the second network is a PLMN.
The session management device of claim 7, wherein the charging correlation information comprises at least one of the following:

an identification of charging for the PDU session allocated by the session management device,

an address of the session management device in the first network, or

an identification of the first network.
The session management device of any of claims 6-9, wherein the access information comprises at least one of the following:

an identification of charging for the PDU session of the second network,

an identification of the second network,

a location of the terminal device, or

an access technology of the terminal device.
A charging device in a first network, comprising:

at least one processor; and

at least one memory storing instructions that, when executed by the at least one processor, cause the charging device at least to:

receive, from a session management device in the first network, a charging request comprising access information of a terminal device maintained in a second network, the access information being for charging for a packet data unit (PDU) session of the terminal device, the PDU session being established in the first network via the second network;

generate a charging data record (CDR) in the first network for the PDU session based on the access information of the terminal device in the second network; and

transmit the CDR in the first network to a billing device in the first network.
The charging device of claim 11, wherein the first network is a public land mobile network (PLMN) and the second network is a stand-alone non-public network (SNPN) ; or

the first network is a SNPN and the second network is a PLMN.
The charging device of claim 11 or 12, wherein the access information comprises at least one of the following:

an identification of charging for the PDU session of the second network,

an identification of the second network,

a location of the terminal device, or

an access technology of the terminal device.
A first billing device in a first network, comprising:

at least one processor; and

at least one memory storing instructions that, when executed by the at least one processor, cause the first billing device at least to:

receive, from a charging device in the first network, a first charging data record (CDR) in the first network for a packet data unit (PDU) session of a terminal device, the PDU session being established in the first network via a second network;

receive, from a second billing device in the second network, a second CDR in the second network for the PDU session; and

correlate the first CDR and the second CDR.
The first billing device of claim 14, wherein:

the first network is a public land mobile network (PLMN) and the second network is a stand-alone non-public network (SNPN) ; or

the first network is a SNPN and the second network is a PLMN.
A policy control device in a second network, comprising:

at least one processor; and

at least one memory storing instructions that, when executed by the at least one processor, cause the policy control device at least to:

receive, from an access management device in a first network via an interface between the access management device and the policy control device, a request for access information of a terminal device maintained in the second network for charging for a packet data unit (PDU) session of the terminal device, the PDU session being established in the first network via the second network; and

transmit the access information of the terminal device in the second network to the access management device in the first network via the interface.
The policy control device of claim 16, wherein the policy control device is further caused to:

receive, from the access management device in the first network via the interface, charging correlation information for the PDU session in the first network; and

transmit the charging correlation information to a session management device in the second network device.
The policy control device of claim 16 or 17, wherein the interface is protected via a security edge protection proxy (SEPP) .
The policy control device of any of claims 16-18, wherein the access information comprises at least one of the following:

an identification of charging for the PDU session of the second network,

an identification of the second network,

a location of the terminal device, or

an access technology of the terminal device.
The policy control device of any of claims 16-19, wherein:

the first network is a public land mobile network (PLMN) and the second network is a stand-alone non-public network (SNPN) ; or

the first network is a SNPN and the second network is a PLMN.
A session management device in a second network, comprising:

at least one processor; and

at least one memory storing instructions that, when executed by the at least one processor, cause the session management device at least to:

receive, from a policy control device in the second network, charging correlation information for a packet data unit (PDU) session of a terminal device, the PDU session being established in a first network via the second network; and

transmit, to a charging device in the second network device, a charging request comprising the charging correlation information.
The session management device of claim 21, wherein the charging correlation information comprises at least one of the following:

an identification of charging for the PDU session allocated by a session management device in the first network,

an address of the session management device in the first network, or

an identification of the first network.
The session management device of claim 21 or 22, wherein:

the first network is a public land mobile network (PLMN) and the second network is a stand-alone non-public network (SNPN) ; or

the first network is a SNPN and the second network is a PLMN.
A charging device in a second network, comprising:

at least one processor; and

at least one memory storing instructions that, when executed by the at least one processor, cause the charging device at least to:

receive, from a session management device in the second network, a charging request comprising charging correlation information for a packet data unit (PDU) session of a terminal device, the PDU session being established in a first network via the second network;

generate a charging data record (CDR) in the second network for the PDU session based on the charging correlation information; and

transmit the CDR in the second network to a billing device in the second network.
The charging device of claim 24, wherein the charging correlation information comprises at least one of the following:

an identification of charging for the PDU session allocated by a session management device in the first network,

an address of the session management device in the first network, or

an identification of the first network.
The charging device of claim 24, wherein the charging device is caused to generate the CDR in the second network by:

performing inter-operator charging based on a wholesale tariff of a provider of the first network for the terminal device for the PDU session.
The charging device of claim 24, wherein the CDR in the second network comprises the charging correlation information.
The charging device of any of claims 24-28, wherein:

the first network is a public land mobile network (PLMN) and the second network is a stand-alone non-public network (SNPN) ; or

the first network is a SNPN and the second network is a PLMN.
A second billing device in a second network, comprising:

at least one processor; and

at least one memory storing instructions that, when executed by the at least one processor, cause the second billing device at least to:

receive, from a charging device in the second network, a charging data record (CDR) in the second network for a packet data unit (PDU) session of a terminal device, the PDU session being established in a first network via a second network; and

transmit the CDR to a first billing device in the first network.
The second billing device of claim 29, wherein:

the first network is a public land mobile network (PLMN) and the second network is a stand-alone non-public network (SNPN) ; or

the first network is a SNPN and the second network is a PLMN.
A method comprising:

transmitting, at an access management device in a first network, to a policy control device in a second network via an interface between the access management device and the policy control device, a request for access information of a terminal device maintained in the second network for charging for a packet data unit (PDU) session of the terminal device, the PDU session being established in the first network via the second network;

receiving the access information of the terminal device in the second network from the policy control device in the second network via the interface; and

transmitting the access information of the terminal device in the second network to a session management device in the first network.
A method comprising:

receiving, at a session management device in a first network from an access management device in the first network, access information of a terminal device maintained in a second network for charging for a packet data unit (PDU) session of the terminal device, the PDU session being established in the first network via the second network; and

transmitting, to a charging device in the first network, a charging request comprising the access information of the terminal device in the second network.
A method comprising:

receiving, at a charging device in a first network from a session management device in the first network, a charging request comprising access information of a terminal device maintained in a second network, the access information being for charging for a packet data unit (PDU) session of the terminal device, the PDU session being established in the first network via the second network;

generating a charging data record (CDR) in the first network for the PDU session based on the access information of the terminal device in the second network; and

transmitting the CDR in the first network to a billing device in the first network.
A method comprising:

receiving, at a first billing device in a first network from a charging device in the first network, a first charging data record (CDR) in the first network for a packet data unit (PDU) session of a terminal device, the PDU session being established in the first network via a second network;

receiving, from a second billing device in the second network, a second CDR in the second network for the PDU session; and

correlating the first CDR and the second CDR.
A method comprising:

receiving, at a policy control device in a second network from an access management device in a first network via an interface between the access management device and the policy control device, a request for access information of a terminal device maintained in the second network for charging for a packet data unit (PDU) session of the terminal device, the PDU session being established in the first network via the second network; and

transmitting the access information of the terminal device in the second network to the access management device in the first network via the interface.
A method comprising:

receiving, at a session management device in a second network from a policy control device in the second network, charging correlation information for a packet data unit (PDU) session of a terminal device, the PDU session being established in a first network via the second network; and

transmitting, to a charging device in the second network device, a charging request comprising the charging correlation information.
A method comprising:

receiving, at a charging device in a second network from a session management device in the second network, a charging request comprising charging correlation information for a packet data unit (PDU) session of a terminal device, the PDU session being established in a first network via the second network;

generating a charging data record (CDR) in the second network for the PDU session based on the charging correlation information; and

transmitting the CDR in the second network to a billing device in the second network.
A method comprising:

receiving, at a second billing device in a second network from a charging device in the second network, a charging data record (CDR) in the second network for a packet data unit (PDU) session of a terminal device, the PDU session being established in a first network via a second network; and

transmitting the CDR to a first billing device in the first network.
An apparatus comprising:

means for transmitting, at an access management device in a first network, to a policy control device in a second network via an interface between the access management device and the policy control device, a request for access information of a terminal device maintained in the second network for charging for a packet data unit (PDU) session of the terminal device, the PDU session being established in the first network via the second network;

means for receiving the access information of the terminal device in the second network from the policy control device in the second network via the interface; and

means for transmitting the access information of the terminal device in the second network to a session management device in the first network.
An apparatus comprising:

means for receiving, at a session management device in a first network from an access management device in the first network, access information of a terminal device maintained in a second network for charging for a packet data unit (PDU) session of the terminal device, the PDU session being established in the first network via the second network; and

means for transmitting, to a charging device in the first network, a charging request comprising the access information of the terminal device in the second network.
An apparatus comprising:

means for receiving, at a charging device in a first network from a session management device in the first network, a charging request comprising access information of a terminal device maintained in a second network, the access information being for charging for a packet data unit (PDU) session of the terminal device, the PDU session being established in the first network via the second network;

means for generating a charging data record (CDR) in the first network for the PDU session based on the access information of the terminal device in the second network; and

means for transmitting the CDR in the first network to a billing device in the first network.
An apparatus comprising:

means for receiving, at a first billing device in a first network from a charging device in the first network, a first charging data record (CDR) in the first network for a packet data unit (PDU) session of a terminal device, the PDU session being established in the first network via a second network;

means for receiving, from a second billing device in the second network, a second CDR in the second network for the PDU session; and

means for correlating the first CDR and the second CDR.
An apparatus comprising:

means for receiving, at a policy control device in a second network from an access management device in a first network via an interface between the access management device and the policy control device, a request for access information of a terminal device maintained in the second network for charging for a packet data unit (PDU) session of the terminal device, the PDU session being established in the first network via the second network; and

means for transmitting the access information of the terminal device in the second network to the access management device in the first network via the interface.
An apparatus comprising:

means for receiving, at a session management device in a second network from a policy control device in the second network, charging correlation information for a packet data unit (PDU) session of a terminal device, the PDU session being established in a first network via the second network; and

means for transmitting, to a charging device in the second network device, a charging request comprising the charging correlation information.
An apparatus comprising:

means for receiving, at a charging device in a second network from a session management device in the second network, a charging request comprising charging correlation information for a packet data unit (PDU) session of a terminal device, the PDU session being established in a first network via the second network;

means for generating a charging data record (CDR) in the second network for the PDU session based on the charging correlation information; and

means for transmitting the CDR in the second network to a billing device in the second network.
An apparatus comprising:

means for receiving, at a second billing device in a second network from a charging device in the second network, a charging data record (CDR) in the second network for a packet data unit (PDU) session of a terminal device, the PDU session being established in a first network via a second network; and

means for transmitting the CDR to a first billing device in the first network.
A non-transitory computer readable medium comprising program instructions that, when executed by an apparatus, cause the apparatus to perform at least the method of any of claims 31-38.