A network slicing congestion control method

Abstract

The present invention relates to a network slice congestion control method, comprising: a user equipment UE sends a registration request; an AMF network element or an SMF network element receives network congestion information of a network slice; the AMF network element or the SMF network element obtains a backoff timer value; the AMF network element or the SMF network element sends a registration rejection signaling carrying a backoff timer to the UE. The beneficial effect of the present invention is that the AMF network element or the SMF network element in the present invention dynamically calculates and optimizes the backoff timer value of the user to adapt to the service attributes of the user according to the network congestion information and the user service attributes, thereby achieving control of the network slice congestion situation, meeting the service quality requirements of users or services of different priorities, improving the user experience, and ensuring the overall performance of the communication system.

Description

Technical Field

[0001] The present invention relates to the field of wireless communications, and more specifically, to a network slicing congestion control method. Background Art

[0002] With the emergence of diversified new services in the 5G and cloud era, different industries, services or users have different characteristics and service quality requirements. Since these devices belong to different industrial fields, they have higher requirements for network mobility, security, latency, reliability, and even billing methods. Therefore, 5G networks are required to have capabilities such as fast access, deterministic latency, and extremely high reliability. In response to the above requirements, 5G network slicing technology came into being.

[0003] Network slicing can be treated differently according to the requirements of each customer. Through network slicing, operators can build multiple dedicated, virtualized, and isolated logical networks on a common physical network to meet the differentiated requirements of different customers for the network. Through slicing, traffic can be treated differently and resources can be isolated. Then mobile network operators can treat customers as customers of different tenant types, each with different service requirements. Based on these requirements and service level agreements (SLA), mobile network operators can decide which slice type each tenant uses for management and subscription, bringing greater value returns to mobile network operators.

[0004] Since the load capacity of each network slice is limited after division, when a large number of users / services access the same network slice at the same time, the network slice may be congested. For these congested network slices, the Access and Mobility Management Function (AMF) or Session Management Function (SMF) can reject or delay the access requests initiated by these user equipment (UE) if it receives session management signaling sent by the user equipment (UE).

[0005] In order to prevent further congestion of the network slice caused by the UE repeatedly initiating access request signaling, the AMF or SMF may provide a back-off timer to the UE while rejecting the signaling. The UE associates the Back-off Timer with the Single-Network Slice Selection Assistance Information (S-NSSAI) carried in the Packet Data Unit (PDU) session establishment process. If the UE does not provide S-NSSAI during the PDU session establishment process or the PDU session is transferred from the 4G network, the UE associates the Back-off Timer with no S-NSSAI. Before the Back-off Timer expires, the UE cannot repeatedly initiate session establishment or session modification signaling for the S-NSSAI or no S-NSSAI.

[0006] In the existing solution, the back-off timer (Back-off Timer) value carried by AMF or SMF in the rejection signaling sent to the UE is fixed, without considering the delay requirements and tolerance delay of the user's service. This solution is applicable to users with similar service quality requirements. But it is no longer applicable to users with differentiated service quality. For example, for delay-sensitive users, if the service delay requirement is low, and the configured Back-off Timer is large, then even if the UE accesses the network slice, its service experience will be poor and the user satisfaction will be low. Therefore, the existing method of processing network slice congestion control is not suitable for signaling of high-priority UEs, emergency services, and UEs updating the mobile data switch status. Therefore, it is necessary to dynamically customize the adjustment according to the delay requirements of the user's service and set the Back-off Timer for each user's service characteristics to ensure the user's quality of service (Quality of Service, QoS). Summary of the invention

[0007] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a network slicing congestion control method;

[0008] In a first aspect, a network slice congestion control method is provided, including:

[0009] S1. The user equipment UE sends a registration request to the access and mobility management function AMF network element or the session management function SMF network element in the network;

[0010] S2, the AMF network element or the SMF network element receives the network congestion information of the network slice and the UE service delay information, and determines whether network congestion has occurred in the network slice according to the network congestion information; the network congestion information includes the total number of resources that can be used in the network slice and the total number of resources requested by users or services;

[0011] S3. When network congestion occurs in the network slice, the AMF network element or the SMF network element calculates the user access registration delay according to the UE service delay information, and obtains the user's back-off timer value according to the user access registration delay;

[0012] S4. The AMF network element or the SMF network element sends a registration rejection signaling to the UE, and the registration rejection signaling carries a backoff timer.

[0013] Preferably, S1 comprises:

[0014] S101. The UE obtains configured network slice selection auxiliary information NSSAI;

[0015] S102. The UE determines the requested NSSAI based on the configured NSSAI; the requested NSSAI is composed of one or more single network slice selection auxiliary information S-NSSAI corresponding to the UE's service;

[0016] S103. The UE carries the requested NSSAI in the registration request and sends it to the AMF network element or SMF network element in the network.

[0017] Preferably, in S103, when the UE has no specific service or only needs to use the default network slice, the registration request does not carry the requested NSSAI.

[0018] Preferably, in S3, when network congestion occurs within the network slice, the AMF network element or SMF network element needs to determine the allowed NSSAI before calculating the user access registration delay.

[0019] Preferably, S3 includes:

[0020] S301: The maximum tolerable service delay of user i is recorded as T i , the access registration delay is recorded as T Access , the data transmission delay is recorded as T Trans , T i It is expressed as:

[0021] T i =T Access，i +T Trans，i

[0022] S302, through transformation:

[0023] T Access，i =T i -T Trans，i

[0024] S303, set α i ∈[0,1] is the relaxation factor of user i, and the backoff timer value is recorded as T Back-off，i , T Back-off，i It is expressed as:

[0025] T Back-off，i =(αT Access，i )

[0026] Among them, the relaxation factor α i Depends on the type of business.

[0027] Preferably, in S3, when the number of users is multiple, the AMF network element or SMF network element, after calculating the user access registration delay, sorts all users within a cycle according to the user priority and the user access registration delay.

[0028] Preferably, in S3, after obtaining the user's back-off timer value, the AMF network element or SMF network element updates the S-NSSAI, and broadcasts the S-NSSAI including the back-off timer to each user through the base station.

[0029] Preferably, the network slice congestion control method further includes:

[0030] S5. The UE sets the counter value to the backoff timer value and waits for the backoff timer value to become 0.

[0031] S6. When the back-off timer value corresponding to the UE becomes 0, the UE sends a registration request to the AMF network element or SMF network element again.

[0032] In a second aspect, a computer storage medium is provided, and when the computer program runs on a computer, the computer executes the network slice congestion control method as described in any one of the first aspects.

[0033] In a third aspect, a computer program product is provided. When the computer program product runs on a computer, the computer executes the network slice congestion control method as described in any one of the first aspects.

[0034] The beneficial effect of the present invention is that the AMF network element or SMF network element in the present invention adapts to the user's service attributes by dynamically calculating and optimizing the user's backoff timer value according to network congestion information and user service attributes (such as service tolerance delay, etc.), thereby achieving control over network slice congestion and meeting the service quality requirements of users or services of different priorities, thereby improving user experience and ensuring the overall performance of the communication system. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A flowchart of a network slicing congestion control method provided in this application;

[0036] Figure 2 A flowchart of a network registration request in a 5G wireless network provided for this application;

[0037] Figure 3 A flowchart of an AMF network element or SMF network element updating and broadcasting a backoff timer value provided by this application;

[0038] Figure 4 A schematic diagram of the structure of an S-NSSAI provided in this application;

[0039] Figure 5 A flowchart of configuring a backoff timer value provided in this application. DETAILED DESCRIPTION

[0040] The present invention is further described below in conjunction with embodiments. The description of the following embodiments is only used to help understand the present invention. It should be noted that for ordinary persons in the art, without departing from the principle of the present invention, the present invention can also be modified in some ways, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

[0041] Embodiment 1:

[0042] A network slice congestion control method, such as Figure 1 As shown, including:

[0043] S1. The user equipment UE sends a registration request to the access and mobility management function AMF network element or the session management function SMF network element in the network;

[0044] S2, AMF network element or SMF network element receives network congestion information of the network slice and UE service delay information, and determines whether network congestion occurs in the network slice according to the network congestion information; the network congestion information includes the total number of resources available in the network slice and the total number of resources requested by users or services;

[0045] S3. When network congestion occurs in the network slice, the AMF network element or the SMF network element calculates the user access registration delay according to the UE service delay information (such as the maximum tolerable service delay and the data transmission delay), and obtains the user's back-off timer value according to the user access registration delay;

[0046] S4, AMF network element or SMF network element sends a registration reject (Registration Reject) signaling to the UE, and the registration reject signaling carries a back-off timer.

[0047] It should be noted that if Figure 2 As shown, before the UE needs to use the network slice, it must first send a registration request to the AMF network element or SMF network element. It can be used only after obtaining permission from the AMF network element or SMF network element. When there is no user conflict or congestion, the AMF network element or SMF network element sends a registration acceptance signaling to the UE; when a user conflict or congestion occurs, the AMF network element or SMF network element sends a registration rejection signaling to the UE, and carries a backoff timer at the same time. The backoff timer for each user is dynamically adjusted according to the delay requirements of the user's business to ensure the user's service quality.

[0048] Specifically, S1 includes:

[0049] S101. The UE obtains configured network slice selection auxiliary information (Configured NSSAI);

[0050] The network slice in the Configured NSSAI corresponds to the network slice subscribed by the UE;

[0051] S102. The UE determines the requested network slice selection auxiliary information (RequestedNSSAI) based on the Configured NSSAI; the Requested NSSAI is composed of one or more S-NSSAIs corresponding to the UE's service;

[0052] S103. The UE carries the Requested NSSAI in the registration request and sends it to the AMF network element or SMF network element in the network.

[0053] In S103, when the UE has no specific service or only needs to use the default network slice, the registration request may not carry the Requested NSSAI.

[0054] In addition, after the UE obtains the Configured NSSAI, when the UE needs to use the service, the UE determines the Configured NSSAI corresponding to the current network. If the UE saves the Allowed NSSAI corresponding to the current network, such as the UE has registered with the network, obtains and saves the received Allowed NSSAI, then the UE selects the S-NSSAI corresponding to the service from the Configured NSSAI and the Allowed NSSAI. If the UE does not have the Allowed NSSAI corresponding to the current network, it only selects the S-NSSAI corresponding to the service from the Configured NSSAI.

[0055] In S2, when the AMF network element or SMF network element receives the Requested NSSAI, it first needs to determine whether the network is congested. If there is no congestion, the AMF network element or SMF network element directly accepts the user's registration request.

[0056] Since this application is an optimization of the existing technology for handling congestion problems, no further analysis will be made here for the situation where the network is not congested. When network congestion occurs within the network slice, the AMF network element or SMF network element needs to determine the allowed network slice selection auxiliary information (Allowed NSSAI) before calculating the user access registration delay.

[0057] After receiving the registration request, the AMF network element or SMF network element first authenticates the UE. If authenticated, it obtains the UE's slice selection subscription data (SliceSelection Subscription Data) from the unified data management function (UDM) network element. The slice selection subscription data contains the network slice selection auxiliary information (Subscribed NSSAI) subscribed by the UE, which includes the default network slices and network slices that require secondary authorization. The AMF network element or SMF network element can determine the Allowed NSSAI based on the Requested NSSAI and the Subscribed NSSAI, and then determine whether it can support the Allowed NSSAI. If the AMF network element or SMF network element cannot support these Allowed NSSAIs, the AMF network element or SMF network element needs to trigger AMF network element redirection or SMF network element redirection to select another target AMF network element or target SMF network element that can support these Allowed NSSAIs. Determining the target AMF network element or the target SMF network element can be completed by the source AMF network element or the source SMF network element or the Network Slice Selection Function (NSSF) network element, depending on whether the source AMF network element or the source SMF network element is configured with configuration information for determining the target AMF network element or the target SMF network element. If the source AMF network element or the source SMF network element is not configured with information for determining the target AMF network element or the target SMF network element and the network is deployed with NSSF network elements, the AMF network element relocation (AMF Relocation) or SMF network element relocation (SMF Relocation) can be completed by the NSSF network element.

[0058] The source AMF network element or source SMF network element sends the network slices subscribed by the UE and the Requested NSSAI to the NSSF network element. Based on the received information, the NSSF network element uses the network slices allowed by the UE in the Requested NSSAI as the AllowedNSSAI and the not allowed slices as the Rejected NSSAI, determines the set of AMF network elements or SMF network elements that can support the Allowed NSSAI, and then sends the AMF network element or SMF network element set and the Allowed NSSAI to the source AMF network element or source SMF network element. The source AMF network element or source SMF network element then selects an AMF network element or SMF network element from the AMF network element set or SMF network element set as the target AMF network element or target SMF network element. After the target AMF network element or target SMF network element is determined, the source AMF network element or source SMF network element transfers the registration request message, Allowed NSSAI, and Rejected NSSAI received from the UE to the target AMF network element or target SMF network element.

[0059] The target AMF network element or the target SMF network element then puts the Allowed NSSAI and Rejected NSSAI in the Registration Accept message and sends it to the UE. For the Rejected NSSAI, the AMF network element or the SMF network element will also notify the UE of the unusable range of the rejected network slice.

[0060] Therefore, when the AMF network element or SMF network element receives a registration request carrying Allowed NSSAI, it will wait for the tolerance to dynamically calculate the backoff timer corresponding to the UE based on the priority of the UE and send the registration rejection signaling containing the backoff timer back to the UE. After the backoff timer expires, the UE completes the registration in the AMF network element or SMF network element. If the registration request does not contain Allowed NSSAI, the registration rejection signaling is directly sent back to the UE to alleviate network congestion.

[0061] Additionally, S3 includes:

[0062] S301: The maximum tolerable service delay of user i is recorded as T i , the access registration delay is recorded as T Access , the data transmission delay is recorded as T Trans , T i It is expressed as:

[0063] T i =T Access，i +T Trans，i

[0064] S302, through transformation:

[0065] T Access，i =T i -T Trans，i

[0066] S303, set α i ∈[0,1] is the relaxation factor of user i, and the backoff timer value is recorded as T Back-off，i , T Back-off，i It is expressed as:

[0067] T Back-off，i =(αT Access，i )

[0068] Among them, the relaxation factor α i It is related to the service type. Different types of services have different priorities, tolerance time limits and other limiting factors. For example, for services with higher latency requirements and more sensitive to latency, their α i The smaller the value, the smaller the i The larger the backoff timer value T Back-off，i It can also be called congestion wait time.

[0069] In addition, if Figure 3 In the process of updating and broadcasting the backoff timer by the AMF network element or SMF network element shown, the AMF network element or SMF network element is first initialized, collects UE service delay information, and then calculates the access registration delay of each user based on the delay information. Then, all users in a cycle are sorted according to the user priority and the calculated user access registration delay, and the backoff timer of each user is customized and dynamically calculated, and the S-NSSAI information is updated. Finally, the S-NSSAI information containing the backoff timer is broadcast to each user through the base station. That is to say, in S3, when the number of users is multiple, the AMF network element or SMF network element, after calculating the user access registration delay, sorts all users in a cycle according to the user priority and the user access registration delay. After obtaining the user's backoff timer value, the AMF network element or SMF network element updates the S-NSSAI and broadcasts the S-NSSAI containing the backoff timer to each user through the base station.

[0070] Another example Figure 4 As shown in the figure, the network slice identifier defined in the standard can be S-NSSAI. S-NSSAI is an end-to-end identifier, that is, a slice identifier that can be recognized by UE, base station, and core network equipment. S-NSSAI consists of two parts, namely, slice and service type (Slice / Service Type, SST) and (Slice Differentiation, SD). See Figure 4Among them, SST is used to distinguish the scenario types of network slicing applications and is located in the upper 8 bits of S-NSSAI. In addition, SD is a more detailed distinction between different network slices under the SST level and is located in the lower 24 bits of S-NSSAI.

[0071] Considering the customized nature of network slicing, each operator will deploy different network slices for the application vendors that cooperate with it. Therefore, it is impractical to unify the identification of network slices deployed by operators around the world. However, there are indeed services that are generally supported by most operators around the world. For example, traditional data traffic services, voice services, etc. Therefore, SST values ​​can be divided into standardized and non-standardized values. There are 4 existing standardized SST values, representing eMBB, URLLC, MloT and V2X. Except for V2X introduced in R16, the other 3 values ​​are defined in the R15 standard. See Figure 4 , non-standardized values ​​can be defined by operators based on their deployed network slices. Configure according to the SST standard value. For example, at that time, there were four SST values, representing eMBB, URLLC, MloT, and V2X, which were used to classify the fallback timer.

[0072] In addition, if Figure 5 As shown, after the UE receives the registration rejection signaling in S4, it also obtains the back-off timer associated with the S-NSSAI in the signaling, and the network slice congestion control method also includes:

[0073] S5. The UE sets the counter value to the backoff timer value and waits for the backoff timer value to become 0.

[0074] S6. When the back-off timer value corresponding to the UE becomes 0, the UE sends a registration request to the AMF network element or SMF network element again.

Claims

1. A network slice congestion control method, characterized in that: include: S1. User equipment UE sends a registration request to the access and mobility management function AMF network element or the session management function SMF network element in the network; S2, the AMF network element or the SMF network element receives the network congestion information of the network slice and the UE service delay information, and determines whether network congestion occurs in the network slice according to the network congestion information; The network congestion information includes the total number of resources available in the network slice and the total number of resources requested by users or services; S3. When network congestion occurs in the network slice, the AMF network element or the SMF network element calculates the user access registration delay according to the UE service delay information, and obtains the user's back-off timer value according to the user access registration delay; In S3, when network congestion occurs in the network slice, the AMF network element or the SMF network element needs to determine the allowed NSSAI before calculating the user access tolerance delay; S3 includes: S301: The maximum tolerable service delay of user i is recorded as T i , the access registration delay is recorded as T Access , the data transmission delay is recorded as T Trans , T i It is expressed as: T i =T Access，i +T Trans，i S302, through transformation: T Access，i =T i -T Trans，i S303, set α i ∈[0, 1] is the relaxation factor of user i, and the backoff timer value is recorded as T Back-off，i , T Back-off，i It is expressed as: T Back-off，i =(αT Access，i ) Among them, the relaxation factor α i Related to the type of business; S4. The AMF network element or the SMF network element sends a registration rejection signaling to the UE, and the registration rejection signaling carries a backoff timer.

2. The network slice congestion control method according to claim 1, characterized in that: S1 includes: S101. The UE obtains configured network slice selection auxiliary information NSSAI; S102. The UE determines the requested NSSAI based on the configured NSSAI. The requested NSSAI consists of one or more single network slice selection assistance information S-NSSAI corresponding to the UE's service; S103. The UE carries the requested NSSAI in the registration request and sends it to the AMF network element or SMF network element in the network.

3. The network slice congestion control method according to claim 2, characterized in that: In S103, when the UE has no specific service or only needs to use the default network slice, the registration request does not carry the requested NSSAI.

4. The network slice congestion control method according to claim 3, characterized in that: In S3, when the number of users is multiple, the AMF network element or SMF network element, after calculating the user access tolerance delay, sorts all users within a cycle according to the user priority and the user access tolerance delay.

5. The network slice congestion control method according to claim 4, characterized in that: In S3, after obtaining the user's back-off timer value, the AMF network element or SMF network element updates the S-NSSAI and broadcasts the S-NSSAI including the back-off timer to each user through the base station.

6. The network slice congestion control method according to claim 1, characterized in that: Also includes: S5. The UE sets the counter value to the backoff timer value and waits for the backoff timer value to become 0. S6. When the back-off timer value corresponding to the UE becomes 0, the UE sends a registration request to the AMF network element or SMF network element again.

7. A computer storage medium, characterized in that: The computer storage medium stores a computer program; when the computer program runs on a computer, the computer executes the network slice congestion control method as described in any one of claims 1 to 6.

8. A computer program product, characterized in that When the computer program product runs on a computer, the computer executes the network slice congestion control method as described in any one of claims 1 to 6.

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