Patent Description:
In the LTE communication system, as a type of a communication service and requiring data rate, etc. are diversified, expansion of the LTE frequency and evolution to the <NUM> communication system are actively progressing.

The rapidly evolving <NUM> communication system not only accommodates as many user equipments as possible based on limited radio resources but also supports scenarios of enhanced mobile broadband (eMBB), massive machine type communications (mMTC), and ultra-reliable and low latency communications (URLLC).

In the <NUM> communication system, the network structure to support, from end to end, the user equipments, base stations (radio access networks), cores, and servers is defined, and a network structure that separates the Control Plane for the control signaling functions and the User Plane for the data transmission/reception functions is defined by separating the control signaling functions and data transmission/reception functions performed by a single node (e.g., S-GW, P-GW, etc.) in the existing LTE (<NUM>) communication system.

In this case, various nodes are included in the Control Plane. For example, the Access and Mobility Management Function (AMF) that controls wireless access of the user equipment, the Policy Control Function (PCF) that manages/controls policies such as user equipment information and subscription service information for each user equipment, billing, and the like, the Session Management Function (SMF) that manages/controls a session for using data services for each user equipment, and the Network Exposure Function (NEF) that performs an information sharing function with an external network are included in the Control Plane.

In addition, functions such as the User Plane Function (UPF) may be included in the User Plane.

Non-patent document "3rd Generation Partnership Project; Technical Specification Group Services and Sustem Aspects: Study on enhancement of Ultra-Reliable Low-Latency Communication support in the <NUM> Core network", 3GPP TR <NUM>, retrieved on September <NUM>, <NUM>, provides monitoring QoS activated dynamically by the 5GC for a certain UEs.

Non-patent Literature "Solution for QoS Monitoring for URLLC Services", 3GPP DRAFT; S2-<NUM> provides joint-monitoring of the packet delay in 5GC and <NUM>-AN.

Non-patent Literature "New Solution for KI#<NUM> QoS Monitoring", 3GPP DRAFT; S2-<NUM>, provides a measurement on URLLC transmission by only calculating the one-way latency and/or round trip latency between UPF and UE.

In the <NUM> communication system, an Ultra-Reliable and Low Latency Communication (URLLC) service (hereinafter, referred to as a 'URLLC service') may be provided to a user equipment. At this time, in order to provide the URLLC service smoothly, it may be checked whether traffic related to the URLLC service is properly processed by the UPF, and an appropriate remedial action may be taken according to the checked result. For example, if the SMF transmits an enforcement rule for the URLLC service to the UPF, it may be checked whether the UPF actually operates according to the enforcement rule, and the appropriate remedial action may be taken according to the checked result.

Accordingly, the problem to be solved by the present disclosure is to provide a technology that, when the URLLC service is provided to the user equipment in the <NUM> communication system, monitors whether the traffic related to the URLLC service is being properly processed by the UPF and takes the remedial action according to the monitored result.

The present invention is set out by the appended independent claims. Advantageous embodiments are provided in dependent claims.

The advantages and features of the present disclosure and the methods of accomplishing these will be clearly understood from the following description taken in conjunction with the accompanying drawings. However, embodiments are not limited to those embodiments described, as embodiments may be implemented in various forms. It should be noted that the present embodiments are provided to make a full disclosure and also to allow those skilled in the art to know the full range of the embodiments. Therefore, the embodiments are to be defined only by the scope of the appended claims.

In describing the embodiments of the present disclosure, if it is determined that detailed description of related known components or functions unnecessarily obscures the gist of the present disclosure, the detailed description thereof will be omitted. Further, the terminologies to be described below are defined in consideration of functions of the embodiments of the present disclosure and may vary depending on a user's or an operator's intention or practice. Accordingly, the definition thereof may be made on a basis of the content throughout the specification.

<FIG> shows a diagram conceptually illustrating an architecture <NUM> of the <NUM> communication system according to an embodiment.

The <NUM> communication system represented by the architecture <NUM> of <FIG> will be described. The <NUM> communication system is an advanced technology from the 4th generation LTE telecommunication technology. The <NUM> communication system is a new Radio Access Technology (RAT) and an expanded technology of Long Tern Evolution (LTE) through an evolution of an existing mobile communication network structure or a clean-state structure, and supports extended LTE (eLTE), non-3GPP access, and the like.

However, because the architecture <NUM> illustrated in <FIG> is just an example, the idea of the present disclosure is not interpreted as being limited to the architecture <NUM> illustrated in <FIG> nor the <NUM> communication system.

The architecture <NUM> includes various components (for example, network functions (NF)). Hereinafter, these components will be described.

Referring to <FIG>, an Authentication Server Function (AUSF), an (Core) Access and Mobility Management Function (AMF), a Session Management Function (SMF) <NUM>, a Policy Control Function (PCF), an Application Function (AF), Unified Data Management (UDM), a User Plane Function (UPF) <NUM>, an (Radio) Access Network ((R)AN) or a base station <NUM>, a Data Network (DN) <NUM>, and a User Equipment (UE) <NUM> are shown.

Among these components, the UPF <NUM> may be a component included in a user plane in the <NUM> communication system, and may be referred to as a user plane function <NUM> or the UPF <NUM> in the detailed description. Hereinafter, it will be referred to as the UPF <NUM>.

In addition, the SMF <NUM> may be a component included in a control plane separated from the above-described user plane in the <NUM> communication system, and may be referred to as a session management function <NUM> or the SMF <NUM> in the detailed description. Hereinafter, it will be referred to as the SMF <NUM>.

The SMF <NUM> and the UPF <NUM> each performs not only publicly known functions required in the <NUM> communication system, but also functions intended to be provided in an embodiment. Accordingly, hereinafter, description of the publicly known technology itself performed by each of the SMF <NUM> and the UPF <NUM> will be briefly described or skipped, and the functions intended to be provided in an embodiment will be described in more detail.

<FIG> shows a diagram illustrating a part of the architecture <NUM> of the <NUM> communication system illustrated in <FIG>. Referring to <FIG>, the SMF <NUM>, the UPF <NUM>, the RAN <NUM> (but, hereinafter, referred to as the base station <NUM>), the DN <NUM>, and the UE <NUM> is shown.

The UPF <NUM> is connected to the SMF <NUM> through an N4 interface. In addition, the UPF <NUM> is connected to the base station <NUM> through an N3 interface, is connected to the DN <NUM> through an N6 interface, and is connected to another UPF connected to the SMF <NUM> through an N9 interface.

The UE <NUM> shown in <FIG> accesses the base station <NUM> and is provided with an Ultra-Reliable and Low Latency Communication (URLLC) service while using resources of the base station <NUM>. Traffic related to the URLLC service (User Plane traffic) is processed by the UPF <NUM>. In more detail, when the SMF <NUM> transmits a rule for traffic processing to the UPF <NUM>, the UPF <NUM> processes the traffic related to the URLLC service or various other traffic based on the transmitted rule.

At this time, it may be measured whether the UPF <NUM> is processing the traffic related to the URLLC service according to the above-described rule. If the traffic related to the URLLC service is not being processed according to the rules, a problem may occur in the URLLC service, so determining a cause and a remedial action to resolve the cause may be taken.

Accordingly, according to an embodiment, the SMF <NUM> transmits a measurement rule for a state of traffic processing to the UPF <NUM>. When the UPF <NUM> receives the measurement rule from the SMF <NUM>, the UPF <NUM> measures the state of traffic processing based on the received measurement rule, and transmits a result of the measurement to the SMF <NUM>. For example, the result of the measurement may specifically include information on which part of the UPF <NUM> has a problem. If the SMF <NUM> receives information on the state of the traffic processing from the UPF <NUM>, and there is a problem in a specific part of the UPF <NUM>, the SMF <NUM> considers a predetermined remedial action to resolve the problem of the specific part based on the received information and transmits the predetermined remedial action to the UPF <NUM>. Then, the UPF <NUM> performs the predetermined remedial action received from the SMF <NUM>.

Herein, the information on the state of the traffic processing measured by the UPF <NUM> may also include information on a place at which the state of the traffic processing is measured. The following is an example of a candidate group for the place where the state of the traffic processing may be measured, but the candidate group is not limited thereto.

Hereinafter, a procedure for a monitoring method or a measuring method of the traffic processing performed by the SMF <NUM> will be described.

<FIG> shows a diagram illustrating a procedure for a monitoring method of traffic processing performed by the SMF <NUM> according to an embodiment. However, because <FIG> is just an example, the idea of the present disclosure is not limited to those shown in <FIG>.

Referring to <FIG>, the SMF <NUM> transmits a measurement rule for state of traffic processing to UPF <NUM> in a step S100. <FIG> shows an example of the measurement rule. Referring to <FIG>, an identification (ID) for identifying the measurement rule (in <FIG>, it is shown as an UP measurement request ID value), an operation mode, measurement criteria/description, a measurement place, a measurement method, a measurement period, and threshold values of latency and throughput may be included in the measurement rule.

Among these, the operation mode indicates a condition for the UPF <NUM> to transmit the state of the traffic processing to the SMF <NUM>. An 'Event' mode among the operation modes is a mode in which the UPF <NUM> transmits the state of the traffic processing to the SMF <NUM> if a predetermined event occurs. A 'Periodic' mode is a mode in which the UPF <NUM> transmits the state of the traffic processing to the SMF <NUM> every predetermined period. A 'Self' mode is a mode in which the UPF <NUM> transmits the state of the traffic processing to the SMF <NUM> when a predetermined condition in the UPF <NUM> is satisfied.

Next, the measurement criteria/description is information used to specify traffic that is a measurement target. In other words, traffic that satisfies the measurement criteria may be the measurement target.

By using the measurement criteria, the measurement target may be specified in a traffic unit, a flow unit, or a session unit. In addition, the measurement criteria according to an embodiment may specify all traffic regarding a specific customer (e.g., a wild card '*') and if all traffic regarding the specific customer is specified, specific traffic among all traffic may be specified step by step by using the measurement criteria to be mentioned below.

The measurement criteria may include various types of items. For example, n-tuple or a field of packets such as source IP, destination IP, source port, destination port, and protocol may be included in the measurement criteria, but is not limited thereto.

Further, the measurement place is information designating a place where the state of the traffic processing is to be measured by the UPF <NUM>. The candidate group for the measurement places were described above and the candidate group (including ports a, b, c, d, e, f, g, h, i, j, k, and <NUM>) are shown in <FIG>.

Herein, a plurality of 'modules provided to perform the predetermined function in the UPF <NUM>' may be provided in the UPF <NUM>. For example, the UPF <NUM> may include at least one of a module that performs a function according to a packet detection rule (PDR), a module that performs a function according to a forwarding action rule (FAR), and a module that performs a function according to a QoS enforcement rule (QER), and a module that performs a function according to a usage reporting rule (URR). In addition, the ports e, f, g, h, i, j, k, and l through which the traffic is input to or output from each of these modules may also be included in the candidate group of the measurement place.

A process in which the measurement is performed at the measurement place will be described in more detail in <FIG>.

Referring again to <FIG>, the measurement method is information indicating a method of obtaining time information indicating when the traffic processing has been performed. For example, if the measurement method is 'timestamp in packet', the measurement method is a method using a time recorded in a header of the packet, and if the measurement method is 'timestamp in system', the measurement method is a method using an atomic clock provided in the UPF <NUM> or the like.

The measurement period means a time period for measuring the state of the traffic processing. In addition, the threshold values of the latency and the throughput may be included in the measurement rule.

When the measurement rule described heretofore is transmitted from the SMF <NUM> to the UPF <NUM>, the UPF <NUM> measures the state of the traffic processing based on the measurement rule, and the SMF <NUM> receives a measurement result in a step S110. <FIG> shows a diagram illustrating the measurement result that the SMF <NUM> received from the UPF <NUM>. Referring to <FIG>, the measurement result may include an operation mode indicating an occurred event, a measurement criteria indicating traffic measured as a target, a measurement place indicating a place in which the traffic was measured, a measurement method indicating a method in which time information when the measurement was performed was obtained, a measurement period indicating a time period during which the measurement has been performed, and a latency (and a secondary value) and a throughput (and a secondary value) indicating a measured value.

In other words, the measurement result includes information on 'the latency and the throughput when measuring specific traffic for a predetermined period at a specific place. ' This information indicates whether the UPF <NUM> is processing the traffic according to the measurement rule transmitted from the SMF <NUM>. Further, if the UPF <NUM> is processing differently from the measurement rule, the information indicates a place where the processing is being performed and a state at that time.

The SMF <NUM> considers a predetermined remedial action based on the measurement result received in the step S110 from the UPF <NUM>, and transmits the considered remedial action to the UPF <NUM> in a step S120.

Specifically, for example, the SMF <NUM> may recognize that the measurement result received from the UPF <NUM> includes information showing both "event" and "emergency. " In this case, the SMF <NUM> may consider a remedial action reducing resources of the UPF <NUM> allocated to a UE that is not provided with an URLLC service among UEs managed by the UPF <NUM>. Herein, the 'reducing resources' may include, for example, at least one of dropping a packet related to the UE not provided with the URLLC service, adjusting a QoS related value of the UE not provided with the URLLC service, and adjusting a parameter related to reporting packet usage for the UE not provided with the URLLC service, but is not limited thereto.

Alternatively, the SMF <NUM> may shorten a period of session report request received from the UPF <NUM>, and accordingly, a request by a UE for generating a new session may be limited than before.

Alternatively, the SMF <NUM> may determine, based on the measurement result, that the UPF <NUM> can no longer process the traffic according to the measurement rule. In this case, the SMF <NUM> may consider a remedial action on the UE that is provided with the URLLC service among the UEs managed by the UPF <NUM> to be managed by another UPF other than the UPF <NUM>.

As described above, according to an embodiment, it may be measured or monitored whether the UPF <NUM> is processing the traffic according to the measurement rule received from the SMF <NUM>, and if the processing is being performed differently from the measurement rule, a place where the processing is performed and the state of the traffic processing at that time may be measured or monitored. Therefore, if there is a problem based on the measurement result, the SMF <NUM> may consider a remedial action to resolve the problem, and may transmit the remedial action to the UPF <NUM> to make the UPF <NUM> to operate according to the remedial action. Accordingly, it may be monitored whether the URLLC service is smoothly provided to the UE <NUM> in the <NUM> communication system.

Hereinafter, a procedure for a monitoring method of the traffic processing performed by the UPF <NUM> will be described.

<FIG> shows a flowchart illustrating a monitoring method of traffic processing performed by the UPF <NUM> according to an embodiment. However, since <FIG> is just an example, the idea of the present disclosure is not limited to those illustrated in <FIG>.

Referring to <FIG>, in a step S200, the UPF <NUM> receives a measurement rule from the SMF <NUM>. The measurement rule received in the step S200 is identical to the measurement rule transmitted by the SMF <NUM> to the UPF <NUM> in the step S100 shown in <FIG>, and because the measurement rule has already been described in <FIG>, a description thereof will be skipped.

Thereafter, in a step S210, the UPF <NUM> measures a processing state of traffic related to an URLLC service based on the measurement rule received from the SMF <NUM> in the step S200. For example, as shown in <FIG>, it may be assumed that the UPF <NUM> receives the measurement rule from the SMF <NUM>. In this case, the UPF <NUM> measures a traffic state at a measurement place according to the measurement rule. When measuring, a measurement time is measured according to a method specified in a measurement method. If an operation mode is 'Event', when a predetermined event occurs, the UPF <NUM> transmits the measurement result to the SMF <NUM>. When transmitting, latency and secondary values or throughput and secondary values measured at the measurement place are also transmitted.

Herein, an operation in which the UPF <NUM> measures the traffic state at the measurement place will be described as an example.

(Example <NUM>) Time when the traffic is processed in a specific module may be measured. In this case, the measurement place may be designated as one of the UPF <NUM> or each module (a PDR, a FAR, a QER, and an URR) in the UPF <NUM>. For example, when the UPF <NUM> is designated as the measurement place, a time period from when the traffic is input to the port a to when the traffic is output from the port b is measured as the latency. This is the same when either the PDR, the FAR, the QER, or the URR is designated as the measurement place.

(Example <NUM>) Time when the traffic is processed in at least two modules may be measured. In this case, at least two modules may be designated as the measurement place. For example, if the PDR and the FAR are designated as the measurement place, a time period from when the traffic is input to the port e and then output from the port f to when the traffic is input to the port g and then output from the port h is measured as the latency.

(Example <NUM>) Time when the traffic is transmitted between a module and another module may be measured. In this case, the measurement place may be separate UPFs 200A and 200B, and, for example, a time period from when the traffic is output from the port c to when the traffic is input to the port d is measured as the latency.

(Example <NUM>) Transmission time of the traffic on a specific interface may be measured. For example, when the port a is designated as the measurement place, a time period from when the traffic is transmitted from the UPF 200A to the base station <NUM> through the port a to when the traffic is transmitted from the base station <NUM> to the UPF 200A through the port a again, in other words, round trip time may be measured as the latency. In this case, the traffic is transmitted and received through the N3 interface. This is the same when the port b is designated as the measurement place, and in this case, the traffic is transmitted and received through the N6 interface.

(Example <NUM>) Examples <NUM> to <NUM> illustrate that the time period is measured based on one single traffic. Alternatively, a plurality of traffic, a flow including a plurality of traffic, or a session including a plurality of flows may be applied, as a unit, to the above-described Examples <NUM> to <NUM>. For example, if the flow including a plurality of traffic is applied to the Example <NUM>, a time period from when all traffic included in the flow is input to the port a to when all traffic is output from the port b is measured as the latency. Further, if the flow including a plurality of traffic is applied to the Example <NUM>, a time period from when all traffic included in the flow is input to the port e and then output from the port f to when all traffic is input to the port g and then output from the port h is measured as the latency. Herein, whether a plurality of traffic is input to or output from each port may be identified based on (bidirectional) n-tuple or a field of each traffic.

Thereafter, in a step S220, the UPF <NUM> transmits the measurement result of the processing state measured in the step S210 to the SMF <NUM>. The measurement result is transmitted according to the operation mode in the measurement rule received from the SMF <NUM> in the step S200. In other words, if the operation mode is 'Event,' the measurement result is transmitted when a predetermined event occurs, and if the operation mode is 'Periodic,' the measurement result is transmitted periodically.

After the measurement result is transmitted to the SMF <NUM> in the step S220, the SMF <NUM> may consider a predetermined remedial action based on the measurement result. In a step S230, the UPF <NUM> receives and performs the remedial action. The step S230 may not be performed according to an embodiment. Since the remedial action performed in the step S230 has already been described, a description thereof will be skipped.

As described above, according to an embodiment, whether the UPF <NUM> is processing the traffic according to the measurement rule received from the SMF <NUM>, and if the processing is being performed differently from the measurement rule, a place where the processing is being performed and the state thereof at that time may be measured or monitored. Therefore, if there is a problem based on the measurement result, the SMF <NUM> may consider the remedial action to resolve the problem, and may transmit the remedial action to the UPF <NUM> so that the UPF <NUM> operates according to the remedial action.

Claim 1:
A method of monitoring processing of traffic performed by a session management function, SMF, (<NUM>) in <NUM> communication system, the method comprising:
transmitting a measurement rule for a processing state of traffic to a user plane function, UPF (<NUM>); and
receiving information on the processing state of the traffic from the UPF (<NUM>) in response to the transmitted measurement rule,
wherein the measurement rule includes a measurement place at which the processing state of the traffic is measured, and
wherein the measurement place includes a group of ports among:
a first port of the UPF (<NUM>) used for input/output of the traffic with a radio access network, RAN (<NUM>), a second port of the UPF (<NUM>) used for input/output of the traffic with a data network, DN (<NUM>), a third port of the UPF (<NUM>) used for input/output of the traffic with another UPF (<NUM>) connected to the SMF (<NUM>), and a fourth port of a module performing a predetermined function provided in the UPF (<NUM>).