The present disclosure relates to wireless networks and communications, and more specifically relates to a method and a Session Management Function (SMF) entity for handling a signaling procedure for a Voice over fifth generation (Vo5G) network.
BACKGROUND
[0002] In the present scenario, various standard available procedures provided by third generation partnership project (3GPP) for a voice call in a 5G network (e.g., Non-Standalone (NSA) network) is through an Evolved Packet System (EPS) fallback (as shown in FIG. 1) or by extending Single Radio Voice Call Continuity (SRVCC) support to a third generation/UMTS Terrestrial Radio Access Network (3G/UTRAN) from a fifth generation/new generation Radio Access Network (5G/NG-RAN) (as shown in FIG. 2). Few options have been proposed by different vendors for executing a Vo5G call (i.e., complete call through 5G RAN and 5G core like using InterWorking and Mediation Function (IWF) to Policy Control Function (PCF) for HTTP <-> DIAMETER communication by using Rx interface for Internet Protocol (IP) Multimedia Subsystem (IMS) related procedures). Some of the prior art references are given below:
[0003] CN111373774B discloses an Application Function (AF) for peer-to-peer (P2P) communication provided to affect routing. A core network element associates Protocol Data Unit (PDU) sessions and optimizes a User plane (UP) path for peer-to-peer traffic. UP selection, reselection, configuration, reconfiguration may be performed to support peer-to-peer (P2P) traffic routing. The P2P traffic between a pair of UEs is routed or rerouted through the bridge. The bridge may be established between a first UP and a second UP, and/or between associated RAN nodes. One or more application functions may be included along the bridge path. The Policy Control Function (PCF), e.g., in response to a trigger from the AF, directs the underlying resource to route P2P traffic via the bridge. The Session Management Function (SMF) directs the

underlying resource configuration or reconfiguration of the user plane data path to route P2P traffic via the bridge. The first SMF of the first UP and the second SMF of the second UP may cooperate to establish a desired traffic route. One or more UPFs may be used to support P2P traffic detection.
[0004] WO2020176198A1 discloses a telecommunication system including routing devices, a Quality of Service (QoS) controller, a policy-management device, and a flow-management device. The QoS controller or flow-management device can receive a request from a terminal to create a specialized flow (SF), e.g., for a non-audio, non-video media type. If the request is associated with an authorized user, a setup message can be sent comprising a QoS indicator. The system can create the SF permitting data exchange between the terminal and a routing device. The SF can have QoS characteristics associated with the QoS indicator. In some examples, the terminal can receive network-address information, determine an associated network resource, and send a flow-request message indicating a non-audio, non-video media type. The terminal can then exchange data on the network port with a peer network terminal.
[0005] WO2020251432A1 relates generally to the field of optimizing network resources. More particularly, it relates to optimizing network resources for voice service sessions provided via a packet-switched network.
[0006] US11039018B2 discloses a PCF device receiving from an SMF, a policy establishment request message requesting a charging control rule for a PDU session of a wireless device. In response to the policy establishment request message, the PCF sends to a Core Charging Function (CUF) a charging policy request message requesting charging policy information for the PDU session. The PCF receives from the CUF a charging policy response message. The charging policy response message comprises the charging policy information. The charging policy information comprises a first charging method. Based on the charging policy information, the PCF determines a charging control rule for the PDU session. The PCF sends to the SMF a policy establishment response message comprising the charging control rule. The SMF enforces the charging control rule.

[0007] US10986622B2 provides systems, apparatuses, methods, and computer-readable media for selecting a transmission configuration indication Transmission Configuration Indicator (TCI) State for receiving downlink transmissions. In one example a processor/UE is configured to determine one or more candidate TCIs for a downlink slot; determine a scheduling offset between a physical downlink shared channel (PDSCH) and a physical downlink control channel (PDCCH); prioritize the candidate TCIs based on the scheduling offset; identify a highest priority candidate TCI; and select the highest priority candidate TCI for receiving the PDSCH.
[0008] While the prior arts cover various approaches for handling a signaling procedure for a Vo5G network, but there is no specific procedure mentioned for the Vo5G call (i.e., NG-RAN, 5G Core (5GC) and Internet Protocol (IP) Multimedia Subsystem (IMS)) in a Stand-Alone (SA) mode. In light of the above-stated discussion, there is a need to overcome the above stated disadvantages.
OBJECT OF THE DISCLOSURE
[0009] A principal object of the present disclosure is to provide a method and a Session Management Function (SMF) entity for handling a signaling procedure for a Voice over 5G (Vo5G) network.
[0010] Another object of the present disclosure is to provide a Vo5G core signalling procedure using the SMF entity for an Rx (FMS) related messages instead of a PCF (Policy Control Function) entity, where the PCF entity needs to be configured with policies related to FMS sessions as requested by the SMF entity.
SUMMARY
[0011] Accordingly, the present disclosure provides a signalling method for a Vo5G network. The method includes configuring, by a Session Management Function (SMF) entity, at least one of an internet protocol (IP) Multimedia Subsystem (FMS) session-related function, an IP address allocation function, and a

policy enforcement function through a receiver (Rx) interface for delivering a multimedia communications service over an IP network. The multimedia communications service comprises at least one of a voice service, a video service, and a text messaging service.
[0012] The method includes sending, by the SMF entity, a message to an IMS Proxy-Call Session Control Function (P-CSCF) entity and receiving, by the SMF entity (138), the message from the P-CSCF. Further, the SMF entity requests a PCF entity for policies for FMS sessions and Protocol Data Unit (PDU) sessions. The method is implemented in a microservice-based architecture.
[0013] The PCF entity is specific to a Quality of Service (QoS) requirement, whereas a non-QoS respective message is used for at least one of a provisioning function, a reporting function, a session abortion function on the Rx interface. The PCF entity may configure policies related to FMS sessions as requested by the SMF entity. Further, a Binding Support Function (BSF) entity maintains session binding with the SMF entity.
[0014] These and other aspects herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the invention herein without departing from the spirit thereof.
BRIEF DESCRIPTION OF FIGURES
[0015] The invention is illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the drawings. The invention herein will be better understood from the following description with reference to the drawings, in which:
[0016] FIG. 1 illustrates an example scenario depicting a voice call in a 5G network through an EPS (Evolved Packet System) fallback, according to prior art.

[0017] FIG. 2 illustrates an example scenario depicting a voice call in a 5G network by extending an SRVCC (Single Radio Voice Call Continuity) support to a 3G/UTRAN from a 5G/NG-RAN, according to prior art.
[0018] FIG. 3 illustrates various hardware components of a Session Management Function (SMF) entity for handling signaling procedure for a Vo5G network.
[0019] FIG. 4 illustrates a flow chart of a signaling method for the Vo5G network.
[0020] FIG. 5 illustrates a sequence diagram of a signaling method for a Vo5G during session establishment/modification when QoS/policy parameters are required from a PCF entity, according to prior art.
[0021] FIG. 6 illustrates a sequence diagram of a signaling method for a Vo5G during session establishment/modification when QoS/policy parameters are required from the PCF (Policy Control Function) entity, according to the present disclosure.
[0022] FIG. 7 illustrates a sequence diagram of a signaling method during Session modification/termination when QOS/policy parameters are not required from the PCF entity, according to prior art.
[0023] FIG. 8 illustrates a sequence diagram of a signaling method during session modification/termination when QOS/policy parameters are not required from a PCF entity, according to the present disclosure.
[0024] FIG. 9 illustrates IP multimedia subsystem (FMS) architecture.
[0025] FIG. 10 illustrates an example microservice-based architecture.
DETAILED DESCRIPTION
[0026] In the following detailed description of the invention, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be obvious to a person skilled in the art that the invention may be practiced with or without these specific details. In other instances, well known methods, procedures and components have not been described in details so as not to unnecessarily obscure aspects of the invention.

[0027] Furthermore, it will be clear that the invention is not limited to these alternatives only. Numerous modifications, changes, variations, substitutions and equivalents will be apparent to those skilled in the art, without parting from the scope of the invention.
[0028] The accompanying drawings are used to help easily understand various technical features and it should be understood that the alternatives presented herein are not limited by the accompanying drawings. As such, the present disclosure should be construed to extend to any alterations, equivalents and substitutes in addition to those which are particularly set out in the accompanying drawings. Although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are generally only used to distinguish one element from another.
[0029] The present disclosure focuses on achieving a signalling method for a Vo5G network. The method includes configuring at least one of an IMS session-related function, an IP address allocation function, and a policy enforcement function through a receiver (Rx) interface for delivering at least one multimedia communications service over an IP network. The at least one multimedia communications service comprises at least one of a voice service, a video service, and a text messaging service. Further, the method includes sending a message to an FMS Proxy-Call Session Control Function (P-CSCF) entity and receiving the message from the P-CSCF. Further, an SMF entity requests a PCF entity for policies for IMS sessions and Protocol Data Unit (PDU) sessions. The signalling method is implemented in a microservice-based architecture.
[0030] Unlike existing techniques, the proposed technique can be used for executing Vo5G (complete call through 5G RAN and 5G core like using InterWorking and Mediation Function (RVF) to Policy Control Function (PCF) for HTTP <-> DIAMETER communication by using Rx interface for FMS related procedures). The Rx interface provides multiple session related information within VoLTE network. In the proposed technique, as all NF's (Network Function's) communicate on HTTP only, it can be leveraged to reduce signalling load in network with an SMF for Rx messaging instead of PCF. All the messages

where the PCF is not providing QoS (Quality of service) and just relaying the message can be better optimised. With 5G bringing millennial of use cases, the PCF is supposed to handle QoS requests of many folds in numbers as compared to its predecessor. So, keeping the PCF specific to QoS and policy handling will keep it light weighted in near future. The proposed method can be used to reduce signaling on a next generation core network (NGC) side.
[0031] FIG. 1 illustrates an example scenario depicting a voice call in a 5G network (100) (i.e., Vo5G) through an EPS (Evolved Packet System) fallback, according to prior art. The 5G network (100) includes a UE (102), an eNB (104a), a gNB (104b), a Serving Gateway (SGW) entity (106), a Mobile Management Entity (MME) entity (108), a 5GC (110), an Access and Mobility Management Function (AMF) entity (112), a Policy Control Function (PCF) entity (114), a Session Management Function (SMF)+PGW-C entity (116), a UPF+PGW-C entity (118), and an FMS core (120). The UE (102) may be, for example, but not limited to a cellular phone, a smart phone, a Personal Digital Assistant (PDA), a wireless modem, a tablet computer, a laptop computer, a Universal Serial Bus (USB) dongle, an Internet of Things (IoT), a virtual reality device, an immersive system, or the like.
[0032] In general, a Vo5G (or Voice over New radio or VoNR) is a process by which voice calls can be handled over the 5G network (100 or 200). It is the IP Multimedia System (FMS) core (120) (explained in the FIG. 9) based voice calling services that use the 5G network (100 or 200) for its source of Internet Protocol (IP) voice processing.
[0033] The New Radio (NR) network communication is a 5G radio access technology and the advanced and updated form of a 4G radio access technology. Two main types of voice services (e.g., Carrier-Grade Voice Service and over-the-top (OTT) Voice Services) that will be available over a 5G mobile networks. The Carrier-Grade Voice Service has strict QoS support and does not belong to the public Internet Voice over the VoNR or the Vo5G. The OTT voice services will continue to exist in 5G networks, and they will continue to be provided through

the mobile internet access on the best effort principle by using network neutrality (e.g., Viber®, WhatsApp®, Skype®, or the like).
[0034] The 3GPP has specified that the 5G system uses the 4G voice/video communication architecture and still provides voice/video communication services based on the IMS core (120). Further, the VoLTE and VoNR are different access modes for the FMS voice/video communication services.
[0035] The FMS core (120) is a standards-based architectural framework for delivering multimedia communications services such as voice, video and text messaging over IP networks. In general, the UE (102) (e.g., mobile phone) provides voice call services over a circuit-switched-style network, rather than strictly over an IP packet-switched network. Alternative methods of delivering voice (VoIP) or other multimedia services have become available on the UE (102), but they have not become standardized across the industry. The FMS is an architectural framework that provides such standardization.
[0036] The FMS core (120) refers to the standard for a telecommunication system which controls multimedia services accessing different networks. The FMS core (120) is based on an all-IP network. The FMS core (120) can map and realise all communication services between the different parties during switching and transfer. The FMS core (120) is primarily used in mobile networks but also in fixed-line networks.
[0037] The PCF entity (114) provides policy control for session management related functionality, for access and mobility related functionality, for UE access selection and PDU session selection related functionality and supports negotiation of future background data transfers. Further, the PCF entity (114) has a bunch of interfaces defined that allows it to receive information from a big number of network entities - the AMF entity (112), an SMF entity (138), an Application Function (AF) entity (not shown), a Core Charging Function (CUF) entity (not shown), a User Data Repository (UDR) entity (not shown), a Network Exposure Function (NEF) entity (not shown), a Network Data Analytics Function (NWDAF) entity (not shown), etc. In the 5G network (100 or 200), information

from all these various NFs helps the mobile operators make the optimal decision regarding resource allocation. Ultimately, a Session Management (SM) Association will be created at Session Establishment to oversee a User Plane (UP) connection that is created.
[0038] The SGW entity (106) handles user data traffic, but is not responsible for the signaling data used. The SGW entity (106) transports IP data from the UE (102) to the eNB (104a). The SGW entity (106) also routes incoming and outgoing IP packets for better system collaboration and serves as an anchor for the UE (102) when the UE (102) moves from one eNB (104a) to another. Further, the MME entity (108) is a key component of the standards-defined Evolved Pack Core (EPC) for the eNB (104a). The MME entity (108) provides mobility session management for a Long-Term Evolution (LTE) network and supports subscriber authentication, roaming and handovers to other networks.
[0039] Referring to the FIG. 1, during the EPS fallback procedure, the UE (102) resides in an NG-RAN (i.e., gNB (104b)) of the 5G network (100) and initiates the establishment of the Mobile Originating (MO)/ Mobile Terminating (MT) FMS voice session. The NG-RAN receives a network-initiated PDU session modification request that establishes a QoS stream for voice services. The NG-RAN considers whether or not to allow VoNR, with specific factors including UE capacity, N26 deployment, LTE radio conditions, and whether VoNR is turned on/supported. If the NG-RAN decides EPS Fallback, the 5G network (100) denies the PDU session modification request with special reasons, the 5GC (110) starts waiting for the UE (102) to fall back to 4G network. The NG-RAN chooses to switch or redirect to EPS based on terminal capacity and deployment. When the UE (102) is connected to the EPS, or when the UE (102) switches to EPS via the N26 interface, the UE (102) initiates a Tracking Area Update (TAU) process. If there is no N26 interface, the 5G network (100) redirects to the EPS and the UE (102) initiates EPS attachment and sets the request type to "Handover" in a PDN (Public Data Network) connection request. Thereafter, the SMF+PGW-C entity (116) re-initiates the FMS Voice Services Private Bearer establishment process. The UPF+PGW-C entity (118) enables IP address preservation when connecting

over and changing between the 4G and the 5G access, wherein the 5GC (110) includes a common user plane (UP) anchor point realized by the session management function plus packet data network gateway control plane function (SMF+PGW-C) and the user plane function plus PGW (Packet Data Network Gateway) user plane function. The use of SMF+PGW-C entity (116) allows the policy control and charging rules function (PCRF) used for policy control in the EPC to be replaced by a new dual-mode policy management system that supports 5G-enabled devices regardless of the access technology currently used.
[0040] During the 5G VoNR Procedure, in UE calling or called scenario, the IMS core (120) triggers a QoS establishment process based on an SIP (Session Initiation Protocol) signaling interaction. Based on the QoS establishment process, the 5GC (110) sends a PDU session modification request to the NG-RAN. The NG-RAN reconfigures the user plane and returns the successful modification of the PDU session and informs the 5GC (110), the PCF entity (114), and the FMS core (120). The call continues same as the VoLTE process and information regarding the same is forwarded to the FMS core (120).
[0041] FIG. 2 illustrates an example scenario depicting the voice call in a 5G network (200) by extending an SRVCC support to a 3G/UTRAN from a 5G/NG-RAN, according to prior art.
[0042] Referring to FIG. 2, as per the 3GPP Release 15, the interworking scenarios only include interoperability with a 4G LTE with an Evolved Packet Core (EPC), and also wireless fidelity (Wi-Fi) access. As with the EPC, the new 5GC only supports packet switched (PS) services, making FMS-based voice (sometimes referred to as Vo5G) the only option for the operator-controlled voice services. When the UE (102) moves outside the 5G coverage, the ongoing FMS call can be handed over only to 4G LTE cells, using regular PS handover procedures, and will continue as an FMS call over the PS domain. From 4G, the good old SRVCC to 2G or 3G is available, but the UE (102) will be in trouble when the 5G signal is getting worse and there are no suitable 4G LTE cells in the area. Further, release 16 has added a new option to avoid dropping calls in some scenarios: the SRVCC will be possible from 5G Next Generation Radio Access

Network (NG-RAN) to 3G Universal Terrestrial Radio Access Network (UTRAN).
[0043] In order to avoid adding new interfaces and protocols, the procedure is in some sense a combination of two existing ones: there is a PS handover from 5G to 4G (on the core network side only) happening together with PS-to-CS SRVCC towards an MSC (Mobile Switching Center) server (126) enhanced for the SRVCC. The element that sits in-between the 5G and 3G networks is an MME SRVCC entity (128) (i.e. MME Supporting 5G-SRVCC). It needs to support handovers from NG-RAN (i.e., gnB (104b)) to UTRAN (i.e. 4G RAN (104c)) and SRVCC from E-UTRAN to UTRAN. The second part of the procedure is executed without PS handover to 3G, which means that after switching the 5G SRVCC to UTRAN, all the PDU sessions of the UE (102) are released and will need to be re-established. The SRVCC option may prevent some call drops, especially in the 5G stand-alone deployments, where 5G base stations (gNB (104b)) are not associated with any 4G base stations. The 5G network (200) further comprises the UPF entity (122) that supports the VoNR with the existing Session Establishment and Modification procedures, a Radio Network Controller (RNC) (124) which is in charge of controlling of the UTRAN (104c) and the AMF entity (112) which is already explained in connection with FIG. 1.
[0044] Further, the FMS core (120) may include a P-CSCF entity/ATCF entity/ATGW entity (134), a Service Call Continuity Application Server (SCCAS) (140), an I-CSCF entity (136), a UDM (Unified Data Management) entity (130) and an HSS (Home Subscriber Server) entity (132).
[0045] The P-CSCF entity (134) is an SIP proxy that is the first point of contact for the UE (102) in the 5G network (200). All SIP traffic to and from the UE (102) must go through the P-CSCF entity (134). The P-CSCF entity (134) acts as an ingress and egress point to and from a service provider's FMS domain with respect to an FMS client (not shown). The P-CSCF entity (134) has a large number of responsibilities, including onward routing of registration and session requests to the correct nodes in the 5G network, ensuring an S-CSCF (Serving CSCF) is kept updated on the access network the subscriber is using, providing session

information to the PCRF (Policy and Charging Rules Function) and maintaining a secure connection with the UE (102). The SCCAS (140) assists the telephony applications and multimedia functions to the UE (102). The I-CSCF entity (136) provides full Cx/Dx interface support and selects S-CSCF based on UE capabilities and load. Further, the EVIS core (120) allows to deploy the UDM entity (130) with the 5G Core which can support functionality of the HSS entity (132) for the FMS core (120).
[0046] FIG. 3 illustrates various hardware components of an SMF entity (138) for handling signaling procedure for the Vo5G. The SMF entity (138) may include a processor (310), a communicator (320), a memory (330), a Vo5G signalling controller (340) and an Rx interface (350). The processor (310) is coupled with the communicator (320), the memory (330) and the Vo5G signalling controller (340). The processor (310) is configured to execute instructions stored in the memory (330) and to perform various processes required for the present disclosure. The communicator (320) is configured for communicating internally between internal hardware components and with external devices via one or more networks. The memory (330) also stores instructions to be executed by the processor (310).
[0047] The Vo5G signalling controller (340) controls a data session and a session management functionality of the 5G network (100 or 200). The session management functionality of the 5G network (100 or 200) has the responsibility for the setup of the connectivity for the UE (102) towards the data networks as well as managing the user plane for that connectivity. The Vo5G signalling controller (340) includes a control function that manages the user sessions including establishment, modification, and release of sessions, and it can allocate IP addresses for IP PDU sessions. The Vo5G signalling controller (340) communicates indirectly with the UE (102) through the AMF entity (112) that relays session-related messages between the UE (102) and the SMF entity (138).
[0048] The Vo5G signalling controller (340) supports the session management from access network for creating/updating/removing the session management (SM) context. The Vo5G signalling controller (340)

obtains/subscribes to an SM data in the UDM entity (130). The Vo5G signalling controller (340) supports the user plane, a local PDN and a GTP toward a PGW. The Vo5G signalling controller (340) uses gNB IP provided by the AMF entity (112) (using unified core network (UCN) extension of Common API Framework (CAPIF)) to select GTP-U endpoint. TheVo5G signalling controller (340) supports a notify session released to access network using provided callback URI (Uniform Resource Identifier). The Vo5G signalling controller (340) supports the PDU sessions, where the PDU session provides end-to-end user plane connectivity between the UE (102) and a specific Data Network (DN) through the UPF entity (122). The PDU session supports one or more QoS flows. There is a one-to-one mapping between the one or more QoS flows and QoS profile, i.e. all packets belonging to a specific QoS flow have the same "5G Quality of Service Identifier" (5Q1).
[0049] The Vo5G signalling controller (340) handles at least one of the IP FMS session-related function, an IP address allocation function, and a policy enforcement function through the receiver (Rx) interface (350) for delivering a multimedia communications service over an IP network. The multimedia communications service can be, for example, but not limited to a voice service, a video service, and a text messaging service.
[0050] The Rx interface (350) is used to exchange flow based charging control information between a charging rules function (CRF) entity (not shown) and the application function (AF) entity (not shown). As defined in the stage 2 specifications (3GPP TS 23.125), this information is used by the CRF entity for the flow-based charging (FBC) decisions. The CRF entity exchanges the flow-based charging control information with the traffic plane function (TPF) as specified in 3GPP TS 29.210. Further, the Rx interface (350) may be an intra- or inter-domain interface. One CRF entity shall be able to serve more than one AF entity and one given AF may interact with several CRFs, although on an AF session basis, it shall interact with only a single CRF entity.
[0051] The non-QoS respective messages on the Rx interface (350) are used for provisioning, reporting, session abortion/termination. The non-QoS

respective messages can be, for example, but not limited to an IP CAN type Change, Signalling Bearer Subscription, Provisioning of signalling flows, Reporting IMS capabilities, Reporting ICSI identifiers, Access Network information, Access network charging information, Session abortion/termination messages etc.
[0052] The Vo5G signalling controller (340) may send a message to the IMS Proxy-Call Session Control Function (P-CSCF) entity (134) and receive the message from the P-CSCF (134). Further, the Vo5G signalling controller (340) requests the PCF entity (114) for policies for FMS sessions and PDU sessions. The PCF entity (114) is specific to QoS requirements. The QoS requirements can be, for example, but not limited to speed, throughput, End-to-end latency, Network availability, Reliability parameters like block error ratio for 5G, Jitter, Bandwidth, Connection density etc.
[0053] The Vo5G signalling controller (340) configures Binding Support Function (BSF) entity (not shown) to maintain session binding with the SMF entity (138). The BSF entity is one of the key functions of the 3GPP Service-Based Architecture (SBA) for 5G networks (100 or 200). The BSF entity enables other Network Functions (NFs), for example an IMS Call State Control Function (CSCF) or Network Exposure Functions (NEF), to determine which Policy Control Function (PCF) is holding needed Policy and Accounting information for each active Mobile device Data Session.
[0054] The BSF entity stores the binding information for a certain PDU session, stores the binding information for a certain UE, and enables the subscription to notifications of the PCF entity (114) for the PDU session regi strati on/deregi strati on events. The BSF entity enables the subscription to notifications of the PCF entity (114) for a UE regi strati on/deregi strati on event and enables the discovery of binding information (e.g. the address information of the selected PCF entity (114) for a PDU session).
[0055] FIG. 4 illustrates a flow chart (400) of a signaling method for the Vo5G. The operation (402) is handled by the Vo5G signalling controller (340). At step (402), the method includes configuring the IMS session-related function, the

IP address allocation function, and the policy enforcement function through the Rx interface (350) for delivering the multimedia communications service over the IP network. The multimedia communications service includes the voice service, the video service, and the text messaging service.
[0056] Based on the proposed method, the number of transactions of signaling messages (IMS) will decrease (as explained in FIG. 5 to FIG. 8). Thus, decreasing signal delays/latency. The PCF entity (114) will be required to work only on policy related functions instead of session related functions. The SMF entity (138) being central node will have more authority on FMS sessions. All these messages can be handled by the SMF entity (138), hence the number of messages which passes through the PCF entity (114) can be reduced. After each AAR and AAA message, PCF-PCEF respective RAR/RAA messages are generated to provide information requested in the AAR. These messages can be reduced by using the SMF entity (138).
[0057] In an example, for each call session minimum of 2 and maximum of all messages can exist from the list mentioned below in Table 1. If number of signalling messages is less, it optimizes the resource utilization and signalling delays in the 5G network (100 or 200).
Table 1[0058] FIG. 5 illustrates a sequence diagram (500) of a signaling method for a Vo5G during session establishment/modification when QoS/policy parameters are required from the PCF entity (114), according to prior art.
[0059] At S502, the P-CSCF entity (134) sends an Authorization Authentication request (AAR) (bearer creation) to the PCF entity (114). At S504, the PCF entity (114) sends a Re-authorization request for bearer creation to the SMF entity (138). At S506, the SMF entity (138) sends a Re-Authorization Answer (RAA) to the PCF entity (114), where the RAA corresponds to, for example, a diameter credit control command. At S508, the PCF entity (114) sends Authorization, Authentication and Accounting (AAA) to the P-CSCF entity (134). At S510, the SMF entity (138) sends a Credit-Control-Request (CCR) for a resource allocation complete event to the PCF entity (114). At S512, the PCF entity (114) sends a RACH (Radio Access Channel) response (RAR) to the P-CSCF entity (134). At S514, the P-CSCF entity (134) sends the RAA to the PCF entity (114). At S516, the PCF entity (114) transmits a Clear channel assessment (CCA) to the SMF entity (138).
[0060] FIG. 6 illustrates a sequence diagram (600) of a signaling method for a Vo5G during session establishment/modification when QoS/policy parameters are required from the PCF entity (114), according to the present disclosure.
[0061] At S602, the P-CSCF entity (134) sends an AAR for a bearer creation to the SMF entity (138). At S604, the SMF entity (138) sends an N-PCF FMS policy through an HTTP to the PCF entity (114). At S606, the PCF entity (114) sends a response to the SMF entity (138) based on the N-PCF FMS policy. At S608, the SMF entity (138) sends the AAA to the P-CSCF entity (134). At S610, the SMF entity (138) sends an RAR for a resource allocation complete

event to the P-CSCF entity (134) and at S612, the P-CSCF entity (134) sends the RAA to the SMF entity (138).
[0062] As shown in FIG. 5, the number of signaling messages is 8, whereas, in the proposed method, as shown in FIG. 6, the number of signaling messages is 6, thereby improving the resource utilization in the 5G network (100 or 200).
[0063] FIG. 7 illustrates a sequence diagram (700) of a signaling method during a session modification/termination when QoS/policy parameters are not required from the PCF entity (114), according to prior art.
[0064] At S702, the P-CSCF entity (134) transmits a Send To Resource (STR) for session termination request to the PCF entity (114). At S704, the PCF entity (114) sends an RAR remove to the SMF entity (138). At S706, the SMF entity (138) sends an RAA to the PCF entity (114). At S708, the PCF entity (114) sends STA (session termination acceptance) to the P-CSCF entity (134).
[0065] FIG. 8 illustrates a sequence diagram (800) of a signaling method during session modification/termination, when QoS/policy parameters are not required from the PCF entity (114), according to the present disclosure. At S802, the P-CSCF entity (134) sends an STR for session termination request to the SMF entity (138). At S804, the SMF entity (138) sends an STA (session termination acceptance) to the P-CSCF entity (134). There is no interaction required between the SMF entity (138) and the PCF entity (114).
[0066] As shown in FIG. 7, the number of signaling messages is 4, whereas, in the proposed method, as shown in FIG. 8, the number of signaling messages is 2, thereby improving the resource utilization in the 5G network (100 or 200).
[0067] FIG. 9 illustrates architecture (900) of the FMS core. The FMS core (120) decomposes a network into a distinct application layer (918), a control layer (920) and a transport layer (922) with standardized interfaces to promote scalability, flexibility and extensibility. The FMS core (120) enables secure and reliable multimedia communications between diverse devices (e.g., UE (102)) across diverse networks. The FMS core (120) provides a unified infrastructure and

common mechanisms for controlling, manipulating, routing and managing sessions, as well as implementing authentication, authorization and accounting controls. The IMS core (120) specifications incorporate widely used Internet Engineering Task Force (IETF) recommendations such as the Session Initiation Protocol (SIP) for session control signalling.
[0068] The control layer (920) often referred to as an FMS core, is the cornerstone of the architecture responsible for regulating communications flows. The main functional elements of the control layer include a Call Session Control Function (CSCF) entity (904), the HSS entity (132), a signalling Gateway (SGW) and Media Gateway Control Function (MGCF) entity (910), and a Media Resource Functions (MRF) entity (908).
[0069] The CSCF entity (904) is, a main part of the FMS core (120), responsible for controlling sessions between endpoints (referred to as terminals (an application server (902a and 902b)) in the FMS specifications) and applications. The HSS entity (132) is a master database that maintains all user profile information used to authenticate and authorize subscribers. The SGW/ MGCF entity (910) provides interoperability with a PSTN (916) through a gateway (912). The MRF entity (908) provides media-related functions such as the playing of tones and digital announcements to the application servers (902a and 902b). Further, many FMS functions can be deconstructed into distinct functional elements. In an example, the CSCF function can play three discrete roles: Serving-CSCF (C-CSCF), Interrogating-CSCF (I-CSCF), or Proxy-CSCF (P-CSCF). In the transport layer (922), an IP network (914) and the PSTN (916) communicate with the gateway (912).
[0070] FIG. 10 illustrates an example microservice-based architecture (1000). The microservices architecture (1000) includes a collection of small, autonomous services (1006a-1006d). Based on a request from a client (1002), each service (1006a-1006d) is self-contained and should implement a single business capability within a bounded context through an API gateway (1004). A bounded context is a natural division within a business and provides an explicit boundary within which a domain model exists.

[0071] The various actions, acts, blocks, steps, or the like in the flow chart may be performed in the order presented, in a different order or simultaneously. Further, in some implementations, some of the actions, acts, blocks, steps, or the like may be omitted, added, modified, skipped, or the like without departing from the scope of the invention.
[0072] The embodiments disclosed herein can be implemented using at least one software program running on at least one hardware device and performing network management functions to control the elements.
[0073] It will be apparent to those skilled in the art that other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention. While the foregoing written description of the invention enables one of ordinary skill to make and use what is considered presently to be the best mode thereof, those of ordinary skill will understand and appreciate the existence of variations, combinations, and equivalents of the specific embodiment, method, and examples herein. The invention should therefore not be limited by the above described embodiment, method, and examples, but by all embodiments and methods within the scope of the invention. It is intended that the specification and examples be considered as exemplary, with the true scope of the invention being indicated by the claims.
[0074] The methods and processes described herein may have fewer or additional steps or states and the steps or states may be performed in a different order. Not all steps or states need to be reached. The methods and processes described herein may be embodied in, and fully or partially automated via, software code modules executed by one or more general purpose computers. The code modules may be stored in any type of computer-readable medium or other computer storage device. Some or all of the methods may alternatively be embodied in whole or in part in specialized computer hardware.
[0075] The results of the disclosed methods may be stored in any type of computer data repository, such as relational databases and flat file systems that

use volatile and/or non-volatile memory (e.g., magnetic disk storage, optical storage, EEPROM and/or solid state RAM).
[0076] The various illustrative logical blocks, modules, routines, and algorithm steps described in connection with the embodiments disclosed herein can be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. The described functionality can be implemented in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the disclosure.
[0077] Moreover, the various illustrative logical blocks and modules described in connection with the embodiments disclosed herein can be implemented or performed by a machine, such as a general purpose processor device, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components or any combination thereof designed to perform the functions described herein. A general-purpose processor device can be a microprocessor, but in the alternative, the processor device can be a controller, microcontroller, or state machine, combinations of the same, or the like. A processor device can include electrical circuitry configured to process computer-executable instructions. In another embodiment, a processor device includes an FPGA or other programmable device that performs logic operations without processing computer-executable instructions. A processor device can also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. Although described herein primarily with respect to digital technology, a processor device may also include primarily analog

components. A computing environment can include any type of computer system, including, but not limited to, a computer system based on a microprocessor, a mainframe computer, a digital signal processor, a portable computing device, a device controller, or a computational engine within an appliance, to name a few.
[0078] The elements of a method, process, routine, or algorithm described in connection with the embodiments disclosed herein can be embodied directly in hardware, in a software module executed by a processor device, or in a combination of the two. A software module can reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of a non-transitory computer-readable storage medium. An exemplary storage medium can be coupled to the processor device such that the processor device can read information from, and write information to, the storage medium. In the alternative, the storage medium can be integral to the processor device. The processor device and the storage medium can reside in an ASIC. The ASIC can reside in a user terminal. In the alternative, the processor device and the storage medium can reside as discrete components in a user terminal.
[0079] Conditional language used herein, such as, among others, "can", "may", "might", "may", "e.g.", and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain alternatives include, while other alternatives do not include, certain features, elements and/or steps. Thus, such conditional language is not generally intended to imply that features, elements and/or steps are in any way required for one or more alternatives or that one or more alternatives necessarily include logic for deciding, with or without other input or prompting, whether these features, elements and/or steps are included or are to be performed in any particular alternative. The terms "comprising," "including," "having," and the like are synonymous and are used inclusively, in an open-ended fashion, and do not exclude additional elements, features, acts, operations, and so forth. Also, the term "or" is used in its inclusive sense (and not in its exclusive sense) so that when

used, for example, to connect a list of elements, the term "or" means one, some, or all of the elements in the list.
[0080] Disjunctive language such as the phrase "at least one of X, Y, Z," unless specifically stated otherwise, is otherwise understood with the context as used in general to present that an item, term, etc., may be either X, Y, or Z, or any combination thereof (e.g., X, Y, and/or Z). Thus, such disjunctive language is not generally intended to, and should not, imply that certain alternatives require at least one of X, at least one of Y, or at least one of Z to each be present.
[0081] While the detailed description has shown, described, and pointed out novel features as applied to various alternatives, it can be understood that various omissions, substitutions, and changes in the form and details of the devices or algorithms illustrated can be made without departing from the scope of the disclosure. As can be recognized, certain alternatives described herein can be embodied within a form that does not provide all of the features and benefits set forth herein, as some features can be used or practiced separately from others.

CLAIMS
We Claim:

1. A signalling method for a Voice over fifth generation (Vo5G) network, the
method comprising:
configuring, by a Session Management Function (SMF) entity (138), at least one of an Internet Protocol (IP) Multimedia Subsystem (FMS) session-related function, an IP address allocation function, and a policy enforcement function through a receiver (Rx) interface (350) for delivering a multimedia communications service over an IP network, wherein the multimedia communications service comprises at least one of a voice service, a video service, and a text messaging service.
2. The signalling method as claimed in claim 1, wherein a Policy Control Function (PCF) entity (114) is specific to a Quality of service (QoS) requirement.
3. The signalling method as claimed in claim 1, wherein a non-QoS respective message is used for at least one of a provisioning function, a reporting function, a session abortion function on the Rx interface (350).
4. The signalling method as claimed in claim 1, wherein the signalling method comprises sending, by the SMF entity (138), a message to an FMS Proxy-Call Session Control Function (P-CSCF) entity (134) and receiving, by the SMF entity (138), the message from the P-CSCF (134).
5. The signalling method as claimed in claim 1, wherein the signalling method comprises configuring, by a PCF entity (114), policies related to FMS sessions as requested by the SMF entity (138).

6. The signalling method as claimed in claim 1, wherein the signalling method comprises configuring Binding Support Function (BSF) entity to maintain session binding with the SMF entity (138).
7. The signalling method as claimed in claim 1, wherein the SMF entity (138) requests a PCF entity (114) for policies for FMS sessions and Protocol Data Unit (PDU) sessions.
8. The signalling method as claimed in claim 1, wherein the signalling method is implemented in a microservice-based architecture (1000).
9. A Session Management Function (SMF) entity (138) for a Voice over fifth generation (Vo5G) network, the SMF entity (138) comprising:
a processor (310); a memory (330); and
a Vo5G signalling controller (340), coupled with the processor (310) and the memory (330), configured to:
handle at least one of an internet protocol (IP) Multimedia Subsystem (FMS) session-related function, an IP address allocation function, and a policy enforcement function through a receiver (Rx) interface (350) for delivering a multimedia communications service over an IP network, wherein the multimedia communications service comprises at least one of a voice service, a video service, and a text messaging service.
10. The SMF entity (138) as claimed in claim 9, wherein the Vo5G signalling
controller (340) perform at least one of:
sending a message to an FMS Proxy-Call Session Control Function (P-CSCF) entity (134) and receiving the message from the P-CSCF (134);
configuring Binding Support Function (BSF) entity to maintain session binding with the SMF entity (138); and

requesting a PCF entity (114) for policies for IMS sessions and Protocol Data Unit (PDU) sessions.