Control of Network Slices

Abstract

The visited session management function sends a request of the wireless device for a packet data unit session in the network slice to the home session management function. The visited session management function receives a cause value from the home session management function indicating that the network slice allocation for the number of packet data unit sessions for the network slice has been reached. In one embodiment, the visited session management function receives the request from the wireless device.

Description

Background Art

[0001] Cross - reference to related applications This application claims the benefit of U.S. Provisional Patent Application No. 62 / 947,996, filed on December 13, 2019, which is hereby incorporated by reference in its entirety.

Summary of the Invention

Means for Solving the Problems

[0002] Exemplary embodiments of the present invention enable the implementation of enhanced features and functions in a 5G system. More specifically, embodiments of the techniques disclosed herein may relate to the control of the number of UEs and / or the number of PDU sessions for network slices (e.g., 5G or future communication systems). Throughout this disclosure, UEs, wireless devices, vehicle terminals, and mobile devices are used interchangeably. Throughout this disclosure, base stations, (radio) access networks ((R)ANs), next - generation radio access networks (NG - RANs), new radio node Bs (gNBs), next - generation eNodeBs (ng - eNBs) are used interchangeably. Throughout this disclosure, base stations, radio access networks (RANs), eNodeBs are used interchangeably. The present invention provides, for example, the following. (Item 1) Receiving, by a visited session management function (SMF), a request of a radio device to establish a packet data unit (PDU) session in a network slice identified by a single network slice selection assistance information (S-NSSAI); Transmitting, by the visited SMF, to a home SMF, the PDU session request message including the S-NSSAI; Receiving, by the visited SMF, from the home SMF, a PDU session response message including a cause value indicating that a network slice allocation has reached the number of PDU sessions for the S-NSSAI; Transmitting, by the visited SMF, to the radio device, a PDU session rejection message including the cause value. The method includes the above steps. (Item 2) The PDU session response message further includes: A permitted network slice identifier of a home public land mobile network (PLMN) of the home SMF; and A retry indicator indicating that the radio device retries to establish a second PDU session based on the permitted network slice identifier of the home PLMN. The method according to Item 1 includes the above features. (Item 3) The method according to Item 2 further includes receiving, from the radio device, a request for the second PDU session including the permitted network slice identifier of the home PLMN. (Item 4) Transmitting, by a visited session management function (SMF), to a home SMF, A first single network slice selection assistance information (S-NSSAI) for a visited public land mobile network (PLMN); and A packet data unit (PDU) session creation request message including a second S-NSSAI for a home PLMN; Receiving, by the visited SMF, from the home SMF, A cause value indicating that a network slice allocation has reached the number of PDU sessions for the network slice; A retry indicator; and A PDU session rejection message including a home PLMN permitted S-NSSAI; Based on the visited SMF and the home PLMN permitted S-NSSAI, A visited PLMN permitted S-NSSAI, and Determining the mapping of the home PLMN permitted S-NSSAI; by the visited SMF, to the wireless device, the cause value, the retry indicator, the visited PLMN permitted S-NSSAI, and sending a PDU session rejection message including the mapping of the home PLMN permitted S-NSSAI. (Item 5) The method according to item 4, further comprising receiving, by the visited SMF, a request from the wireless device to establish the PDU session in the network slice. (Item 6) wherein the network slice is a first network slice associated with the first S-NSSAI, and / or one or more of a second network slice associated with the second S-NSSAI. (Item 7) A method comprising: sending, by a visited session management function (SMF), to a home SMF, a packet data unit (PDU) session request message including single network slice selection assistance information (S-NSSAI) for a wireless device; receiving, by the visited SMF, from the home SMF, a PDU session response message including a cause value indicating that the network slice allocation has reached the number of PDU sessions for the S-NSSAI; and sending, by the visited SMF, to the wireless device, a PDU session rejection message including the cause value. (Item 8) The method according to item 7, further comprising receiving, by the visited SMF, a request from the wireless device to establish the PDU session in the network slice, wherein the network slice is a first network slice associated with the first S-NSSAI, and / or one or more of a second network slice associated with the second S-NSSAI. (Item 9) wherein the PDU session response message further includes the permitted network slice identifier of the home public land mobile network (PLMN) of the home SMF, and a retry indicator indicating that the wireless device is to retry to establish a second PDU session based on the permitted network slice identifier of the home PLMN. (Item 10) The method according to item 9, further comprising receiving, from the wireless device, a request for the second PDU session including the permitted network slice identifier of the home PLMN. (Item 11) Transmitting, by a visited session management function (SMF), a request of the wireless device for a packet data unit (PDU) session in a network slice to the home SMF; A method including receiving, by the visited SMF, from the home SMF, a cause value indicating that the network slice allocation has reached the number of PDU sessions for the network slice. (Item 12) The method according to item 11, further comprising receiving, by the visited SMF and from the wireless device, the request. (Item 13) The method according to item 12, wherein the received request is a PDU session establishment request of the wireless device. (Item 14) The method according to any one of items 12 to 13, wherein the received request is a PDU session creation request received via an access and mobility management function (AMF) of a visited public land mobile network (PLMN). (Item 15) The method according to any one of items 12 to 14, wherein the received request includes one or more network slice identifiers including a single network slice selection assistance information (S-NSSAI) of the network slice. (Item 16) The received request is a visited network slice identifier of a network slice of a visited public land mobile network (PLMN), and any method according to items 12 to 15, including one or more of a home network slice identifier of a network slice of a home PLMN. (Item 17) The method according to item 11, wherein the transmitted request includes a PDU session creation request. (Item 18) The method according to item 11, wherein the transmitted request includes one or more network slice identifiers including a single network slice selection assistance information (S-NSSAI) of the network slice. (Item 19) The transmitted request is a visited network slice identifier of a network slice of a visited public land mobile network (PLMN), and The method according to item 11, including one or more of the home network slice identifiers of the network slices of the home PLMN. (Item 20) The method according to item 11, wherein receiving the cause value includes receiving a PDU session response message including the cause value. (Item 21) The PDU session response message includes one or more of a PDU session rejection message and a PDU session acceptance message, according to the method of item 20. (Item 22) Receiving the cause value includes receiving a message including the cause value and a retry indicator, according to the method of item 11. (Item 23) Receiving the cause value includes receiving a message including the cause value and the permitted network slice identifier of the home public land mobile network (PLMN) of the home SMF, according to the method of item 11. (Item 24) Receiving the cause value includes receiving a message including the cause value, the permitted network slice identifier of the home public land mobile network (PLMN) of the home SMF, and a retry indicator indicating that the wireless device retries to establish a second PDU session based on the permitted network slice identifier of the home PLMN, according to the method of item 11. (Item 25) The method according to item 24, further including receiving a request for the second PDU session from the wireless device, wherein the request for the second PDU session includes the permitted network slice identifier of the home PLMN. (Item 26) The method according to any one of items 23 to 25, further including determining a visited PLMN permitted S-NSSAI by the visited SMF and based on the home PLMN permitted S-NSSAI. (Item 27) The method according to any one of items 23 to 26, further including determining a mapping of the home PLMN permitted S-NSSAI by the visited SMF and based on the home PLMN permitted S-NSSAI. (Item 28) The method according to item 11, further including transmitting, by the visited SMF, a message indicating rejection to the wireless device. (Item 29) The method according to item 28, wherein the message indicating the rejection includes the cause value. (Item 30) The method according to item 28, wherein the message indicating the rejection includes a retry indicator. (Item 31) A home session management function (SMF) transmits a message to a network function to subscribe to an event of network slice allocation of a network slice, The home SMF receives a message notifying the event from the network function, The home SMF receives a request from a visited SMF for a radio device to establish a packet data unit (PDU) session in the network slice, The method includes: the home SMF transmits a PDU session response message including a cause value indicating that the network slice allocation has reached the number of PDU sessions for the network slice to the visited SMF. (Item 32) The network function is a network data analytics function (NWDAF), or The method according to item 31, including at least one of operation, administration, and maintenance (OAM). (Item 33) The method according to items 31 to 32, wherein the event includes that the network slice allocation reaches the number of PDU sessions of the network slice. (Item 34) A home session management function (SMF) receives from a visited SMF a first single network slice selection assistance information (S-NSSAI) for a visited public land mobile network (PLMN) and a second S-NSSAI for a home PLMN, in a packet data unit (PDU) session creation request message, The home SMF transmits to the visited SMF a cause value indicating that the network slice allocation has reached the number of PDU sessions for the network slice, a retry indicator, and a home PLMN permitted S-NSSAI, in a PDU session rejection message. The method includes this. (Item 35) The method according to item 35, wherein the retry indicator indicates that the radio device retries to establish a second PDU session based on the home PLMN permitted S-NSSAI. (Item 36) The method according to item 35, further comprising receiving, from the visited SMF, a request of the wireless device for establishing a second PDU session, wherein the request for the second PDU session includes the home PLMN permitted S-NSSAI. (Item 37) Receiving, by the home SMF, from the network function, a message notifying an event of network slice allocation of a network slice; Receiving, by a home session management function (SMF), from a visited SMF, a packet data unit (PDU) session request message including single network slice selection assistance information (S-NSSAI) for a wireless device; A method comprising: transmitting, by the home SMF, to the visited SMF, a PDU session response message including a cause value indicating that network slice allocation has been reached for the number of PDU sessions for the S-NSSAI. (Item 38) The method according to item 37, wherein the event includes that network slice allocation has been reached for the number of PDU sessions of the network slice. (Item 39) The PDU session response message includes the cause value, a retry indicator, and a home PLMN permitted S-NSSAI, and the method according to any one of items 37 to 38. (Item 40) The method according to item 39, further comprising receiving, from the visited SMF, a request of the wireless device for establishing a second PDU session, wherein the request for the second PDU session includes the home PLMN permitted S-NSSAI. (Item 41) Receiving, by a home session management function (SMF), from a visited SMF, a request of a wireless device for establishing a packet data unit (PDU) session in a network slice; A method comprising: transmitting, by the home SMF, to the visited SMF, a cause value indicating that network slice allocation has been reached for the number of PDU sessions for the network slice. (Item 42) The method according to item 41, further comprising transmitting, by the home SMF, to a network function, a message for subscribing to an event of network slice allocation. (Item 43) The method according to item 42, wherein the message for participating in the event includes the single network slice selection assistance information (S-NSSAI) of the network slice. (Item 44) The method according to item 41, further comprising receiving, by the home SMF, from a network function, a message notifying the event. (Item 45) The method according to item 44, wherein the message notifying the event includes the single network slice selection assistance information (S-NSSAI) of the network slice. (Item 46) The method according to item 44, wherein the message notifying the event further includes an action of the home SMF, and the action of the home SMF includes rejecting the request of the wireless device for establishing the PDU session in the network slice. (Item 47) The method according to any one of items 44 to 46, further comprising determining, by the home SMF and based on the message notifying the event, to reject the request of the wireless device for establishing the PDU session in the network slice. (Item 48) The method according to any one of items 46 to 47, wherein the action of the home SMF further includes determining a network slice permitted for the PDU session. (Item 49) The method according to any one of items 44 to 48, further comprising determining, by the home SMF and based on the first message, a network slice permitted for the PDU session. (Item 50) The network function is a network data analytics function (NWDAF), or The method according to any one of items 42 to 49, including at least one of operation, administration, and maintenance (OAM). (Item 51) The method according to items 42 to 49, wherein the event includes reaching the network slice allocation for the number of PDU sessions for the network slice. (Item 52) The method according to items 42 to 49, wherein the event includes reaching the network slice allocation for the number of wireless devices for the network slice. (Item 53) The received request is The visited network slice identifier of the visited public land mobile network (PLMN) slice, and The method according to item 41, including one or more of the home network slice identifiers of the home PLMN network slices. (Item 54) Sending the cause value is The cause value and The permitted network slice identifier of the home public land mobile network (PLMN) of the home SMF, and The method according to item 41, including sending a message including a retry indicator indicating that the wireless device retries to establish a second PDU session based on the permitted network slice identifier of the home PLMN. (Item 55) The method according to item 54, further including receiving, from the visited SMF, a request of the wireless device to establish a second PDU session, wherein the request for the second PDU session includes the permitted network slice identifier of the home PLMN. (Item 56) A visited session management function (SMF) including one or more processors and a memory storing instructions that cause the SMF to execute the method according to any one of items 1 to 30 when executed by the one or more processors. (Item 57) A home session management function (SMF) including one or more processors and a memory storing instructions that cause the SMF to execute the method according to any one of items 31 to 55 when executed by the one or more processors. (Item 58) A non-transitory computer-readable medium including instructions that cause one or more processors to execute the method according to any one of items 1 to 30 when executed by the one or more processors. (Item 59) A non-transitory computer-readable medium including instructions that cause one or more processors to execute the method according to any one of items 31 to 55 when executed by the one or more processors. (Item 60) One or more processors, and when executed by the one or more processors, to the visited SMF, Receiving a request from a wireless device to establish a packet data unit (PDU) session in a network slice identified by a single network slice selection assistance information (S-NSSAI), Transmitting the PDU session request message including the S-NSSAI, Receiving a PDU session response message including a cause value indicating that a network slice allocation has been reached for the number of PDU sessions for the S-NSSAI, and A visited session management function (SMF) including a memory storing instructions for causing the wireless device to transmit a PDU session rejection message including the cause value, One or more processors, and when executed by the one or more processors, to the home SMF, Receiving the PDU session request message including the S-NSSAI, and A system including a home SMF including a memory storing instructions for causing the PDU session response message including the cause value to be transmitted, (Item 61) Receiving, by a base station, from a network function, a message indicating that a first network slice is overloaded because an allocation has been reached for the number of wireless devices for the first network slice, Receiving, by a base station (105), from a wireless device (100), a first radio resource control (RRC) message for an RRC connection for the first network slice, the first RRC message including a first single network slice selection assistance information (S-NSSAI) of the first network slice, Transmitting, by the base station, to the wireless device, an RRC release message including a release cause indicating that an allocation has been reached for the number of wireless devices for the first network slice, Receiving, by the base station, from the wireless device, a second RRC message for an RRC connection, the second RRC message including a second S-NSSAI of a second network slice, (Item 62) The method according to item 61, wherein transmitting the RRC release message is based on the fact that the first network slice is in an overloaded state. (Item 63) The method according to any one of items 61 to 62, wherein the RRC release message includes the waiting time of the first network slice. (Item 64) Receiving, by a base station (105), from a wireless device (110), a first radio resource control (RRC) message for an RRC connection, wherein the first RRC message includes a first single network slice selection assistance information (S-NSSAI) of a first network slice; Transmitting, by the base station, to the wireless device, an RRC release message including a release cause indicating that an allocation limit has been reached for the number of wireless devices for the first network slice; Receiving, by the base station, from the wireless device, a second RRC message for an RRC connection, wherein the second RRC message includes a second S-NSSAI of a second network slice. (Item 65) The method according to item 64, wherein transmitting the RRC release message is based on the fact that the first network slice is in an overloaded state. (Item 66) The method according to any one of items 64 to 65, wherein the RRC release message includes the waiting time of the first network slice. (Item 67) Receiving, by a base station (105), from a wireless device (110), a first radio resource control (RRC) message for an RRC connection, wherein the first RRC message includes a first single network slice selection assistance information (S-NSSAI) of a first network slice; Transmitting, by the base station, to the wireless device, an RRC release message including a release cause indicating that an allocation limit has been reached for the number of UEs for the first network slice; Receiving, by the base station, from the wireless device, a second RRC message for an RRC connection, wherein the second RRC message includes a second S-NSSAI of a second network slice. (Item 68) The method according to item 67, further comprising receiving, by the base station, from a network function, a message indicating that the first network slice is overloaded because the allocation has reached the number of radio devices for the first network slice. (Item 69) The method according to any one of items 67 to 68, wherein transmitting the RRC release message is based on the first network slice being in an overloaded state. (Item 70) The method according to any one of items 67 to 69, wherein the RRC release message includes the waiting time of the first network slice. (Item 71) Receiving, by a base station (105), from a radio device (110), a radio resource control (RRC) message for an RRC connection to a first network slice; Transmitting, by the base station, to the radio device, an RRC release message including a cause value indicating that the first network slice is overloaded. (Item 72) The method according to item 71, wherein the RRC message includes a first single network slice selection assistance information (S-NSSAI) of the first network slice. (Item 73) The method according to any one of items 71 to 72, wherein the RRC message is an RRC setup completion message. (Item 74) The RRC message includes an RRC transaction identifier, a fifth generation short-term mobile subscriber identification information (5G-S-TMSI), a single network slice selection assistance information list information element, a selected public land mobile network identification information element, and one or more of dedicated non-access stratum messages. (Item 75) The method according to any one of items 71 to 74, further comprising receiving, by the base station, from a network function, a message indicating that the first network slice is overloaded. (Item 76) The method according to item 75, wherein the first network slice being in an overloaded state is based on the allocation reaching the number of radio devices for the first network slice. (Item 77) The message includes an overload indication message, an allocation reached indication message, The method according to any one of items 75 to 76, including at least one of the overload start messages. (Item 78) The method according to any one of items 75 to 77, wherein the message includes a first information element indicating a first single network slice selection assistance information (S-NSSAI) of the first network slice. (Item 79) The method according to any one of items 75 to 78, wherein the message includes a second information element indicating that an assignment has been reached for the number of radio devices for the first network slice with respect to the public land mobile network. (Item 80) The method according to any one of items 75 to 79, wherein the message includes a third information element indicating that an assignment has been reached for the number of packet data unit sessions for the first network slice with respect to the public land mobile network. (Item 81) The method according to any one of items 75 to 80, wherein the message includes a fourth information element indicating an action of the base station for RRC connection for the first network slice with respect to the public land mobile network. (Item 82) The method according to item 81, wherein the action of the base station for the RRC connection is a release of the RRC connection. (Item 83) The method according to any one of items 71 to 82, further including determining by the base station that the first network slice is a network slice that has been rejected. (Item 84) The method according to item 83, wherein the RRC release message includes a rejected network slice selection assistance information (S-NSSAI) of the rejected network slice. (Item 85) The method according to any one of items 83 to 84, further including determining by the base station a waiting time of the rejected network slice. (Item 86) The method according to any one of items 83 to 85, wherein the RRC release message includes the waiting time of the rejected network slice. (Item 87) The method according to any one of items 71 to 86, wherein the RRC release message includes a parameter indicating that the first network slice is in an overload state. (Item 88) The method according to any one of items 71 to 86, wherein the RRC release message includes a parameter indicating that the first network slice is overloaded based on the first network slice reaching an assignment to a radio device for the first network slice. (Item 89) The method according to any one of items 71 to 88, further comprising receiving, from the radio device, a second RRC message for an RRC connection to a second network slice. (Item 90) The method according to item 89, wherein the second RRC message includes second single network slice selection assistance information (S-NSSAI) of the second network slice. (Item 91) Transmitting, by a radio device (110), a radio resource control (RRC) message for an RRC connection to a first network slice to a base station (105); and Receiving, by the radio device, from the base station, an RRC release message including a cause value indicating that the first network slice is overloaded. (Item 92) The method according to item 91, wherein the RRC message includes first single network slice selection assistance information (S-NSSAI) of the first network slice. (Item 93) The method according to any one of items 91 to 92, wherein the RRC message is an RRC setup complete message. (Item 94) The RRC message includes an RRC transaction identifier, 5th generation short-term mobile subscriber identity information (5G-S-TMSI), a single network slice selection assistance information list information element, a selected public land mobile network identification information element, and one or more of dedicated non-access stratum messages. (Item 95) The method according to any one of items 91 to 94, wherein the RRC release message includes rejected network slice selection assistance information (S-NSSAI) of the rejected network slice. (Item 96) The method according to item 95, wherein the RRC release message includes a waiting time for the rejected network slice. (Item 97) The method according to any one of items 91 to 96, wherein the RRC release message includes a parameter indicating that the first network slice is in an overloaded state. (Item 98) The method according to any one of Items 91 to 97, wherein the RRC release message includes a parameter indicating that the first network slice is overloaded based on reaching the allocation to the radio device with the number of the first network slice. (Item 99) The method according to any one of Items 91 to 98, further comprising transmitting, to the base station, a second RRC message for an RRC connection to a second network slice. (Item 100) The method according to Item 99, wherein the second RRC message includes second single network slice selection assistance information (S-NSSAI) of the second network slice. (Item 101) A base station (105) including one or more processors and a memory storing instructions that, when executed by the one or more processors, cause the base station to execute the method according to any one of Items 61 to 90. (Item 102) A radio device (110) including one or more processors and a memory storing instructions that, when executed by the one or more processors, cause the radio device to execute the method according to any one of Items 91 to 100. (Item 103) A non-transitory computer-readable medium including instructions that, when executed by one or more processors, cause the one or more processors to execute the method according to any one of Items 61 to 90. (Item 104) A non-transitory computer-readable medium including instructions that, when executed by one or more processors, cause the one or more processors to execute the method according to any one of Items 91 to 100. (Item 105) One or more processors and, when executed by the one or more processors, causing the base station to receive a radio resource control (RRC) message for an RRC connection to a first network slice, and transmit an RRC release message including a cause value indicating that the first network slice is overloaded, and a memory storing instructions for execution, and a base station (105); and One or more processors and, when executed by the one or more processors, causing the radio device to transmit the RRC message, A system comprising a wireless device (100) including a memory storing instructions to cause the wireless device to transmit an RRC release message including the cause value. (Item 106) The system according to item 105, wherein the instruction of the base station further causes the base station to receive a message indicating that the first network slice is overloaded because the allocation has reached the number of wireless devices for the first network slice. (Item 107) The system according to any one of items 105 to 106, wherein the RRC message includes first single network slice selection assistance information (S-NSSAI) of a first network slice. (Item 108) The system according to item 105, wherein the RRC release message indicates that the allocation has reached the number of wireless devices for the first network slice. (Item 109) The system according to any one of items 105 to 108, wherein the instruction of the wireless device causes the wireless device to transmit a second RRC message for RRC connection, and the second RRC message includes second S-NSSAI of a second network slice. (Item 110) The system according to item 109, wherein the instruction of the base station causes the base station to receive the second RRC message. (Item 111) Receiving, by a home network slice selection function (NSSF), from a network function, a first message indicating that the allocation has reached the number of packet data unit (PDU) sessions for a network slice of a home public land mobile network (PLMN); By the home NSSF, from a home session management function (SMF), Receiving a second message including the home PLMN single network slice selection assistance information (S-NSSAI) of the network slice and The visited PLMN S-NSSAI of the network slice; By the home NSSF, Based on the first message, The home PLMN S-NSSAI, and Determining a home PLMN permitted network slice based on the visited PLMN S-NSSAI; A method comprising: the home NSSF sending, to the home SMF, a third message including the permitted S-NSSAI of the home PLMN permitted network slice. (Item 112) The method according to item 111, wherein determining the home PLMN permitted network slice is based on the first message. (Item 113) The method according to any one of items 111 to 112, wherein determining the home PLMN permitted network slice is based on the home PLMN S-NSSAI. (Item 114) The method according to any one of items 111 to 113, wherein determining the home PLMN permitted network slice is based on the visited PLMN S-NSSAI. (Item 115) The method according to any one of items 111 to 114, wherein the third message includes a wireless device identifier of a wireless device requesting a PDU session associated with the first network slice. (Item 116) A network slice selection function (NSSF) sending, to a network function, a message to subscribe to an event of network slice allocation of the first network slice; the NSSF receiving, from the network function, a message notifying the event of network slice allocation of the first network slice; the NSSF receiving, from a session management function (SMF), a request indicating the establishment of at least one packet data unit (PDU) session in the first network slice; A method comprising: the NSSF sending, to the SMF, a message indicating that an allocation has been reached for the number of PDU sessions for the first network slice. (Item 117) The method according to item 116, wherein the message to subscribe to the event includes a single network slice selection assistance information (S-NSSAI) of the first network slice. (Item 118) The network function is a network data analytics function (NWDAF), or The method according to any one of items 116 to 117, including at least one of operation, administration, and maintenance (OAM). (Item 119) The method according to any one of items 116 to 118, wherein the event includes reaching the network slice allocation for the number of PDU sessions for the first network slice. (Item 120) The method according to any one of items 116 to 119, wherein the event includes reaching the network slice allocation for the number of radio devices for the first network slice. (Item 121) Receiving, by a Network Slice Selection Function (NSSF), from a network function, an indication of reaching the allocation for the number of Packet Data Unit (PDU) sessions for a first network slice; Transmitting, by the NSSF, information on a second network slice to a Session Management Function (SMF). (Item 122) The method according to item 121, further comprising transmitting, by the NSSF, to the network function, a message to subscribe to an event of network slice allocation of the first network slice. (Item 123) The method according to item 122, wherein the message to subscribe to the event includes a Single Network Slice Selection Assistance Information (S-NSSAI) of the first network slice. (Item 124) The method according to any one of items 121 to 123, wherein receiving the indication includes receiving a first message notifying an event of network slice allocation of the first network slice. (Item 125) The method according to any one of items 121 to 124, wherein the NSSF is a home NSSF of a home Public Land Mobile Network (PLMN), and the network slice is associated with a home PLMN Single Network Slice Selection Assistance Information (S-NSSAI) of the first network slice. (Item 126) The network function is a Network Data Analytics Function (NWDAF), or an Operation, Administration, and Maintenance (OAM), at least one of which is included in the method according to any one of items 121 to 125. (Item 127) The method according to any one of items 121 to 126, wherein the event includes reaching the network slice allocation for the number of PDU sessions for the first network slice. (Item 128) The method according to any one of items 121 to 126, wherein the event includes reaching the network slice allocation for the number of radio devices for the first network slice. (Item 129) The method according to any one of items 121 to 128, further comprising receiving, by the home NSSF, from a home session management function (SMF), a second message indicating the network slice. (Item 130) The method according to item 129, wherein the second message includes a home PLMN single network slice selection assistance information (S-NSSAI) of the second network slice. (Item 131) The method according to any one of items 129 to 130, wherein the second message includes a visited PLMN single network slice selection assistance information (S-NSSAI) of the second network slice. (Item 132) The method according to any one of items 129 to 131, wherein the second message includes a radio device identifier of a radio device that requests a PDU session associated with the first network slice. (Item 133) The method according to any one of items 129 to 132, further comprising determining, by the NSSF, the second network slice based on the second message. (Item 134) The method according to item 133, wherein the determination is based on the indication that the allocation has been reached for the number of PDU sessions for the first network slice. (Item 135) The method according to any one of items 133 to 134, wherein the determination is based on a home PLMN single network slice selection assistance information (S-NSSAI) of the network slice. (Item 136) The method according to any one of items 133 to 135, wherein the determination is based on a visited PLMN single network slice selection assistance information (S-NSSAI) of the network slice. (Item 137) The method according to any one of items 121 to 136, wherein the second network slice is an authorized network slice of a home public land mobile network (PLMN). (Item 138) The method according to any one of items 121 to 137, wherein the NSSF is a home NSSF of the home PLMN, and the SMF is a home SMF of the home PLMN. (Item 139) The method according to any one of items 121 to 138, further comprising transmitting, by the NSSF, to the SMF, a third message including a second network slice of the home PLMN authorized network slice. (Item 140) The method according to item 139, wherein the third message includes a wireless device identifier of a wireless device that requests a PDU session associated with the first network slice. (Item 141) Receiving, by a Network Slice Selection Function (NSSF), from a first network function, a request for establishing at least one Packet Data Unit (PDU) session in a first network slice; The method includes transmitting, by the NSSF, to the SMF, an indication that an allocation has been reached for the number of PDU sessions for the first network slice. (Item 142) The method according to item 141, further comprising transmitting, by the NSSF, to a second network function, a message for subscribing to an event of network slice allocation of the first network slice. (Item 143) The method according to item 142, wherein the message for subscribing to the event includes a single Network Slice Selection Assistance Information (S-NSSAI) of the first network slice. (Item 144) The method according to any one of items 141 to 143, further comprising receiving a first message for notifying an event of network slice allocation of the first network slice. (Item 145) The method according to any one of items 141 to 144, wherein the NSSF is a home NSSF of a home Public Land Mobile Network (PLMN), and the network slice is associated with a home PLMN single Network Slice Selection Assistance Information (S-NSSAI) of the first network slice. (Item 146) The second network function is a Network Data Analytics Function (NWDAF), or the method according to any one of items 141 to 145, including at least one of Operation, Administration, and Maintenance (OAM). (Item 147) The method according to any one of items 141 to 146, wherein the event includes reaching the network slice allocation for the number of PDU sessions for the first network slice. (Item 148) The method according to any one of Items 141 to 146, wherein the event includes reaching the network slice allocation for the number of radio devices for the first network slice. (Item 149) The method according to any one of Items 141 to 148, wherein transmitting the indication that the allocation has been reached includes transmitting a message including the indication, and the message further includes information on a second network slice. (Item 150) The method according to Item 149, wherein the message includes a home PLMN single network slice selection assistance information (S-NSSAI) of the second network slice. (Item 151) The method according to any one of Items 149 to 150, wherein the message includes a visited PLMN single network slice selection assistance information (S-NSSAI) of the second network slice. (Item 152) The method according to any one of Items 149 to 151, wherein the message includes a radio device identifier of a radio device that requests a PDU session associated with the first network slice. (Item 153) The method according to any one of Items 149 to 152, further including determining, by the NSSF, the second network slice based on the message. (Item 154) The method according to Item 153, wherein the determination is based on the indication that the allocation has been reached for the number of PDU sessions for the first network slice. (Item 155) Receiving, by a session management function (SMF), from a network function, an indication that the allocation has been reached for the number of packet data unit (PDU) sessions of a first network slice; Transmitting, by the SMF, to a network slice selection function (NSSF), A request indicating the establishment of at least one packet data unit (PDU) session in the first network slice, and The indication that the allocation has been reached for the number of packet data unit (PDU) sessions for the first network slice. (Item 156) The method according to item 155, further comprising receiving, by the SMF, at an access and mobility management function (AMF), a PDU session creation message including the single network slice selection assistance information (S-NSSAI) of the first network slice. (Item 157) The method according to any one of items 155 to 156, further comprising transmitting, by the SMF, to the network function, a message for subscribing to an event of network slice allocation of the first network slice. (Item 158) The method according to item 157, wherein the message for subscribing to the event includes the single network slice selection assistance information (S-NSSAI) of the first network slice. (Item 159) The method according to any one of items 157 to 158, further comprising receiving, from the network function, a message notifying the event of network slice allocation of the first network slice, the message including the indication that the allocation has been reached. (Item 160) The method according to any one of items 155 to 158, further comprising receiving, by the SMF, from the NSSF, a second S-NSSAI of a second network slice. (Item 161) The method according to item 160, further comprising transmitting, by the SMF, to a radio device requesting the first network slice, from an access and mobility management function (AMF), a PDU session rejection message. (Item 162) The method according to item 161, wherein the PDU session rejection message includes the second S-NSSAI of the second network slice. (Item 163) The method according to any one of items 161 to 162, wherein the PDU session rejection message includes a retry indicator. (Item 164) A network slice selection function (NSSF) comprising: one or more processors; and a memory storing instructions that, when executed by the one or more processors, cause the NSSF to perform the method according to any one of items 111 to 154. (Item 165) A session management function (SMF) comprising one or more processors and a memory storing instructions that, when executed by the one or more processors, cause the SMF to execute the method described in any one of items 155 to 163. (Item 166) A non-transitory computer-readable medium comprising instructions that, when executed by one or more processors, cause the one or more processors to execute the method described in any one of items 111 to 154. (Item 167) A non-transitory computer-readable medium comprising instructions that, when executed by one or more processors, cause the one or more processors to execute the method described in any one of items 155 to 163. (Item 168) One or more processors and, when executed by the one or more processors, cause the NSSF to Receive from a network function an indication that an allocation has been reached for the number of packet data unit (PDU) sessions for a first network slice, And a memory storing instructions that cause the session management function (SMF) to transmit information about a second network slice, and a network slice selection function (NSSF). The SMF, comprising one or more processors and a memory storing instructions that, when executed by the one or more processors, cause the SMF to Receive the information about the second network slice, and a system comprising the SMF. (Item 169) One or more processors and, when executed by the one or more processors, cause the NSSF to Receive from a first network function a request indicating the establishment of at least one packet data unit (PDU) session in a first network slice, And a memory storing instructions that cause the first network function to transmit an indication that an allocation has been reached for the number of PDU sessions for the first network slice, and a network slice selection function (NSSF). The first network function, comprising one or more processors and a memory storing instructions that, when executed by the one or more processors, cause the SMF to Send the request. A system including a storage memory storing instructions to cause receiving the indication that the allocation has been reached for the number of PDU sessions for the first network slice, and including the first network function. (Item 170) One or more processors, and when executed by the one or more processors, cause the SMF to receive from a network function an indication that an allocation has been reached for the number of packet data unit (PDU) sessions for a first network slice, send to a network slice selection function (NSSF) a request indicating establishment of at least one packet data unit (PDU) session in the first network slice, and a session management function (SMF) including a memory storing instructions to cause sending the indication that the allocation has been reached for the number of PDU sessions for the first network slice. The NSSF including one or more processors, and when executed by the one or more processors, cause the NSSF to receive the request indicating establishment of at least one packet data unit (PDU) session in the first network slice, and a system including the NSSF including a memory storing instructions to cause receiving the indication that the allocation has been reached for the number of PDU sessions for the first network slice. (Item 171) A wireless device (110) sends to a session management function (SMF) a first request to create a first PDU session in a first network slice, receives from the SMF a rejection message including permitted single network slice selection assistance information (S-NSSAI) for a second network slice, and a retry indicator determines the second network slice based on the permitted S-NSSAI for the second network slice and the retry indicator, and sends to the SMF a second request to create a second PDU session in the second network slice based on the rejection message. (Item 172) A wireless device (110) transmits a first request to a session management function (SMF) to create a first PDU session in a first network slice, and the wireless device receives, from the SMF, a rejection message indicating the allowed single network slice selection assistance information (S-NSSAI) of a second network slice, and determines the second network slice based on the rejection message, and the wireless device transmits a second request to the SMF and based on the rejection message to create a second PDU session in the second network slice. A method comprising. (Item 173) A wireless device (110) transmits a first request to a session management function (SMF) to create a first PDU session in a first network slice, and the wireless device receives, from the SMF, a response message including the allowed single network slice selection assistance information (S-NSSAI) of a second network slice, and the wireless device transmits a second request to the SMF and based on the response message to create a second PDU session in the second network slice. A method comprising. (Item 174) The method according to item 173, wherein the first request is a non-access stratum message. (Item 175) The method according to any one of items 173 to 174, wherein the first request includes the first single network slice selection assistance information (S-NSSAI) of the first network slice. (Item 176) The method according to any one of items 173 to 175, wherein the response message is a PDU session rejection message. (Item 177) The method according to any one of items 173 to 176, wherein the response message is a PDU session commitment message. (Item 178) The method according to any one of items 173 to 177, wherein the response message further includes a retry indicator. (Item 179) The method according to item 178, wherein the retry indicator indicates that the wireless device retries to establish the second PDU session based on the second network slice. (Item 180) The method according to any one of items 173 to 179, further comprising determining the second network slice based on the permitted S-NSSAI of the second network slice and the retry indicator. (Item 181) The method according to any one of items 173 to 179, further comprising determining the second network slice based on the response message. (Item 182) The method according to any one of items 173 to 181, wherein the second request is a non-access stratum message. (Item 183) The method according to any one of items 173 to 182, wherein the second request includes second single network slice selection assistance information (S-NSSAI) of the second network slice. (Item 184) The method according to any one of items 173 to 183, wherein the response message further includes a cause value indicating that the network slice allocation has reached the number of radio devices for the first network slice for the PLMN. (Item 185) Receiving, by a session management function (SMF), a first request from a radio device (110) to create a first PDU session in a first network slice; Transmitting, by the SMF, a response message including permitted single network slice selection assistance information (S-NSSAI) of a second network slice to the radio device and based on the first request; Receiving, by the SMF, a second request from the radio device to create a second PDU session in the second network slice. (Item 186) A radio device (100) comprising one or more processors and a memory storing instructions that, when executed by the one or more processors, cause the radio device to execute the method according to any one of items 171 to 184. (Item 187) A session management function (SMF) comprising one or more processors and a memory storing instructions that, when executed by the one or more processors, cause the SMF to execute the method according to item 185. (Item 188) A non - transitory computer - readable medium including instructions that, when executed by one or more processors, cause the one or more processors to execute the method according to any one of items 171 to 184. (Item 189) A non - transitory computer - readable medium including instructions that, when executed by one or more processors, cause the one or more processors to execute the method according to item 185. (Item 190) One or more processors and, when executed by the one or more processors, a wireless device transmits a first request to a session management function (SMF) to create a first PDU session in a first network slice; receives, from the SMF, a response message including permitted single network slice selection assistance information (S - NSSAI) of a second network slice; and transmits a second request to the SMF to create a second PDU session in the second network slice based on the response message. A wireless device (100) including a memory storing instructions for causing the above - described operations to be executed. The SMF includes one or more processors and, when executed by the one or more processors, the SMF receives the first request; transmits the response message based on the first request; and includes a memory storing instructions for causing the SMF to receive the second request. A system including the SMF.

Brief Description of the Drawings

[0003] Examples of some of the various embodiments of the present invention are described herein with reference to the drawings.

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Mode for Carrying Out the Invention

[0030] Throughout the present disclosure, AMF, SMF (e.g., H-SMF, V-SMF), UPF, PCF, NWDAF, OAM, (H-)NSSF are exemplary network functions that can be implemented as network elements on (dedicated) hardware and / or as any of the network nodes shown in FIG. 4, or as software instances executed on (dedicated) hardware and / or shared hardware, or as virtualized functions instantiated on a suitable platform.

[0031] The following acronyms are used throughout the present disclosure: 5G Fifth Generation Mobile Network 5GC 5G Core Network 5GS 5G System 5G-AN 5G Access Network 5QI 5G QoS Indicator ACK Acknowledgment AF Application Function AMBR Aggregate Maximum Bit Rate AMF Access and Mobility Management Function AN Access Network ANDSP Access Network Discovery and Selection Policy APN Access Point Name ARP Allocation and Retention Priority BD Billing Domain CCNF Common Control Network Function CDR Charging Data Record CHF Charging Function CIoT Cellular IoT CN Core Network CP Control Plane C-V2X Cellular Vehicle-To-Everything DAB Digital Audio Broadcast DDN Downlink Data Notification DDoS Distributed Denial of Service for Services DL Downlink DN Data Network DN-AAA Data Network Authentication Authorization and Accounting DNN Data Network Name DTMB Digital Terrestrial Multimedia Broadcast eNodeB Evolved Node B EPS Evolved Packet System E-UTRAN Evolved Universal Terrestrial Radio Access Network FDD Frequency Division Duplex FQDN Fully Qualified Domain Name F-TEID Fully Qualified TEID GPSI General Public Subscription Identifier GTP GPRS Tunneling Protocol GUTI Global Unique Temporary Identifier GW Gateway HTTP HyperText Transfer Protocol ID Identifier IMEI International Mobile Equipment Identity IMEI DB IMEI Database IMS IP Multimedia Core Network Subsystem IMSI International Mobile Subscriber Identity IP Internet Protocol IP-CAN IP Connectivity Access Network L2 Layer 2 (Data Link Layer) L3 Layer 3 (Network Layer) LADN Local Area Data Network LI Lawful Interception LAN Local Area Network MAC Media Access Control MEI Mobile Equipment Identifier MICO Mobile Initiated Connection Only MME Mobility Management Entity MO Mobile Originated MSISDN Mobile Subscriber ISDN MT Mobile Terminated N3IWF Non-3GPP Interworking Function NAI Network Access Identifier NAS Non-Access Stratum NAT Network Address Translation NB-IoT NarrowBand IoT NEF Network Exposure Function NF Network Function NGAP Next Generation Application Protocol NR New Radio NG-RAN NR Radio Access Network NRF Network Repository Function NSI Network Slice Instance NSSAI Network Slice Selection Assistance Information NSSF Network Slice Selection Function NWDAF Network Data Analytics Function OAM Operation, Administration, and Maintenance OCS Online Charging System OFCS Offline Charging System PCC Policy and Charging Control PCF Policy Control Function PCRF Policy and Charging Rules Function PDN Packet Data Network PDU Packet Data Unit PEI Permanent Equipment Identifier PGW PDN Gateway PLMN Public Land Mobile Network ProSe Proximity Services QFI QoS Flow Identifier QoS Quality of Service RM Registration Management RA Random Access RAN Radio Access Network RAT Radio Access Technology RRC Radio Resource Control RM Registration Management S1-AP S1 Application Protocol SBA Service-Based Architecture SEA Security Anchor Function SGW Serving Gateway SCM Security Context Management SM Session Management SMF Session Management Function SMSF SMS Function S-NSSAI Single Network Slice Selection Assistance Information SS Synchronization Signal SSC Session and Service Continuity SUCI Served User Correlation ID SUPI Subscriber Permanent Identifier TA Tracking Area TAI Tracking Area Identity TCP Transmission Control Protocol TEID Tunnel Endpoint Identifier TMSI Temporary Mobile Subscriber ID UCMF UE Radio Capacity Management Function UDR Unified Data Repository UDM Unified Data Management UDP User Datagram Protocol UE User Equipment UL Uplink UL CL Uplink Classifier UPF User Plane Function V2X Vehicle-To-Everything WLAN Wireless Local Area Network XML Extensible Markup Language

[0032] Exemplary FIGS. 1 and 2 illustrate a 5G system including an access network and a 5G core network. An exemplary 5G access network may include an access network connecting to a 5G core network. The access network may include NG-RAN 105 and / or non-3GPP (registered trademark) AN 165. An exemplary 5G core network may connect to one or more 5G access networks 5G-AN and / or NG-RAN. The 5G core network may include functional elements or network functions as in Exemplary FIG. 1 and Exemplary FIG. 2, and interfaces may be used for communication between the functional elements and / or network elements.

[0033] In an embodiment, a network function may be a processing function within a network that may have a functional behavior and / or an interface. The network function may be implemented as a network element on dedicated hardware, and / or as a network node as illustrated in FIGS. 3 and 4, or as a software instance operating on dedicated hardware and / or shared hardware, or as a virtualized function instantiated on a suitable platform.

[0034] In one example, the Access and Mobility Management Function (AMF) 155 may include the following functions (some of the functions of the AMF 155 may be supported in a single instance of the AMF 155): termination of the RAN 105 CP interface (N2), termination of the NAS (N1), NAS encryption and integrity protection, registration management, connection management, reachability management, mobility management, lawful interception (for AMF 155 events and interface to the LI system), providing transport for session management (SM) messages between the UE 100 and the SMF 160, a transparent proxy for routing SM messages, access authentication, access authorization, providing transport for SMS messages between the UE 100 and the SMSF, a Security Anchor Function (SEA), which interacts with the AUSF 150 and the UE 100, receiving intermediate keys established as a result of the UE 100's authentication process, a Security Context Management (SCM) which receives keys from the SEA to use to derive access network specific keys, etc.

[0035] In one example, the AMF 155 may support non-3GPP® access networks through an N2 interface with the N3IWF 170, NAS signaling with the UE 100 on the N3IWF 170, authentication of UEs connected on the N3IWF 170, mobility management, authentication, and separate security context state for the UE 100 connected via a non-3GPP® access 165 or simultaneously connected via a 3GPP® access 105 and a non-3GPP® access 165, support for coordinated RM contexts valid for the 3GPP® access 105 and the non-3GPP® access 165, support for CM management contexts for the UE 100 for connectivity over non-3GPP® access, etc.

[0036] In an embodiment, the AMF155 area may include one or more AMF155 sets. An AMF155 set may include several AMF155s that provide a given area and / or network slice. In an embodiment, multiple AMF155 sets may be per AMF155 area and / or network slice. An application identifier may be an identifier that can be mapped to a specific application traffic detection rule. The configured NSSAI may be an NSSAI that can be prepared in the UE100. The DN115 access identifier (DNAI) for a DNN may be an identifier for user plane access to the DN115. The initial registration may be related to the registration of the UE100 in the RM deregistration 500, 520 state. The N2AP association of the UE100 may be logical for each association of the UE100 between the 5G AN node and the AMF155. The N2AP UE-TNLA binding may be a binding between the N2AP association of the UE100 and the association of the dedicated transport network layer (TNL) for a given UE100.

[0037] In one example, the Session Management Function (SMF) 160 may include one or more of the following functions (one or more of the SMF160 functions may be supported by a single instance of the SMF160): session management (including session establishment, modification, and release, such as maintaining a tunnel between the UPF 110 and the AN 105 node), IP address allocation and management for the UE 100 (including optional authentication), selection and control of the UPF function, configuration of traffic operations in the UPF 110 for routing traffic to an appropriate destination, termination of the interface to the policy control function, policy enforcement and QoS control section, lawful interception (SM events and interface to the LI System), termination of the SM part of NAS messages, downlink data notification, initiation of AN-specific SM information, transmission to the (R)AN 105 via the AMF 155 on N2, determination of the SSC mode of the session, roaming function, handling of local enforcement for applying the QoS SLA (VPLMN), charging data collection and charging interface (VPLMN), lawful interception (in the VPLMN for SM events and interface to the LI System), support for interaction with the external DN 115 for forwarding signaling for PDU session authorization / authentication by the external DN 115, etc.

[0038] In one example, the User Plane Function (UPF) 110 may include one or more of the following functions (some of the UPF110 functions may be supported by a single instance of the UPF110): anchor point for intra / inter-RAT mobility (when applicable), external PDU session point of connection to the DN 115, packet routing and forwarding, packet inspection and user plane part for policy rule enforcement, lawful interception (UP collection), traffic usage reporting, uplink classifier to support routing of traffic flows to the data network, branch point to support multi-home PDU sessions, QoS handling for the user plane, uplink traffic verification (SDF to QoS flow mapping), transfer level packet marking in the uplink and downlink, downlink packet buffering, downlink data notification trigger, and the like.

[0039] In one example, the IP address management of the UE 100 may include the allocation and release of the IP address of the UE 100, and / or the update of the allocated IP address. The UE 100 may set the requested PDU type during the PDU session establishment procedure based on its IP stack function and / or configuration. In an embodiment, the SMF 160 may select the PDU type of the PDU session. In an embodiment, when the SMF 160 receives a request with the PDU type set to IP, the SMF 160 may select the PDU type IPv4 or IPv6 based on the DNN configuration and / or operator policy. In an embodiment, the SMF 160 may provide a cause value to the UE 100 to indicate whether other IP versions are supported on the DNN. In an embodiment, when the SMF 160 receives a request for the PDU type IPv4 or IPv6 and the requested IP version is supported by the DNN, the SMF 160 may select the requested PDU type.

[0040] In an exemplary embodiment, the 5GC elements and the UE 100 may support the following mechanisms: During the PDU session establishment procedure, the SMF 160 may send an IP address to the UE 100 via SM NAS signaling. IPv4 address allocation via DHCPv4 and / or IPv4 parameter configuration may be used when the PDU session is established. When IPv6 is supported, allocation of an IPv6 prefix may be supported via IPv6 stateless autoconfiguration. In an example, the 5GC network element may support IPv6 parameter configuration via stateless DHCPv6.

[0041] The 5GC may support allocation of a static IPv4 address and / or a static IPv6 prefix based on the subscription information in the UDM 140 and / or based on a per-subscriber, per-DNN basis configuration.

[0042] The user plane function (UPF 110) may handle the user plane path of the PDU session. The UPF 110 that provides an interface to the data network may support the function of the PDU session anchor.

[0043] In an example, the policy control function (PCF) 135 may support a unified policy framework for governing network behavior, provide policy rules to control plane functions for enforcing policy rules, implement a front end for accessing subscription information related to policy decisions in the user data repository (UDR), etc.

[0044] The network exposure function (NEF) 125 may provide means for securely exposing services and capabilities provided by 3GPP (registered trademark) network functions, means for translating between information exchanged with the AF 145 and information exchanged with internal network functions, means for receiving information from other network functions, etc.

[0045] In one example, the Network Repository Function (NRF) 130 may support a service discovery function, such as receiving an NF discovery request from an NF instance, providing information about the discovered NF instance (to be discovered) to the NF instance, maintaining information about available NF instances and the services they support, etc.

[0046] In one example, the NSSF 120 may select a set of network slice instances serving the UE 100 and may determine the permitted NSSAI. In one example, the NSSF 120 may determine the set of AMF 155 used to serve the UE 100 and / or, based on the configuration, may query the NRF 130 to determine a list of candidate AMF 155s.

[0047] In one example, the data stored in the UDR may include at least user subscription data, including at least a subscription identifier, a security certificate, access and mobility related subscription data, session related subscription data, policy data, etc.

[0048] In one example, the AUSF 150 may support an Authentication Server Function (AUSF 150).

[0049] In an embodiment, the Application Function (AF) 145 may interact with the 3GPP (registered trademark) core network to provide services. In an embodiment, based on the operator deployment, the application function may be trusted by the operator to directly interact with the relevant network functions. An application function not permitted by the operator to directly access the network functions may use an external exposure framework (e.g., via the NEF 125) to interact with the relevant network functions.

[0050] In an embodiment, the control plane interface between the (R)AN 105 and the 5G core may support connections of multiple different types of ANs (e.g., 3GPP™ RAN 105, N3IWF 170 for untrusted access 165) to the 5GC via a control plane protocol. In an embodiment, the N2 AP protocol may be used for both 3GPP™ access 105 and non-3GPP™ access 165. In an embodiment, the control plane interface between the (R)AN 105 and the 5G core may support separation between the AMF 155 and other functions such as the SMF 160 that may be required to control the services supported by the AN (e.g., control of UP resources within the AN 105 for a PDU session).

[0051] In an embodiment, the 5GC may provide policy information from the PCF 135 to the UE 100. In an embodiment, the policy information may include an access network discovery and selection policy, a UE 100 route selection policy (URSP), an SSC mode selection policy (SSCMSP), a network slice selection policy (NSSP), a DNN selection policy, a non-seamless offload policy, etc.

[0052] In an embodiment, as illustrated in the exemplary FIGS. 5A and 5B, registration management (RM) may be used to register or deregister the UE / user 100 with the network and establish a user context within the network. Connection management may be used to establish and release a signaling connection between the UE 100 and the AMF 155.

[0053] In an embodiment, the UE 100 may register with the network to receive services that require registration. In an embodiment, the UE 100 may periodically update its registration with the network to remain reachable (periodic registration updates), or upon mobility (e.g., mobility registration updates), or to update its capabilities, or to renegotiate protocol parameters.

[0054] In an embodiment, the initial registration procedure illustrated in exemplary FIGS. 8 and 9 may involve the execution of network access control functions (e.g., user authentication and access authorization based on the subscription profile of UDM 140). Exemplary FIG. 9 is a continuation of the initial registration procedure illustrated in FIG. 8. As a result of the initial registration procedure, the identification of the serving AMF 155 may be registered with the UDM 140.

[0055] In an embodiment, the registration management (RM) procedure may be applicable via both 3GPP (registered trademark) access 105 and non-3GPP (registered trademark) access 165.

[0056] Exemplary FIG. 5A may illustrate the RM state of the UE 100 as observed by the UE 100 and the AMF 155. In an exemplary embodiment, two RM states, RM deregistration 500 and RM registration 510, may be used in the UE 100 and the AMF 155 and may reflect the registration state of the UE 100 in the selected PLMN. In an embodiment, in the RM deregistration state 500, the UE 100 may not be registered with the network. Since the UE 100 context of the AMF 155 may not hold valid location or routing information for the UE 100, the UE 100 may not be reachable by the AMF 155. In an embodiment, the UE 100 context may be stored in the UE 100 and the AMF 155. In an embodiment, in the RM registration state 510, the UE 100 may be registered with the network. In the RM registration 510 state, the UE 100 may receive services that may require registration with the network.

[0057] In an exemplary embodiment, two RM states, RM deregistration 520 and RM registration 530, may be used in the AMF 155 for the UE 100 and may reflect the registration state of the UE 100 in the selected PLMN.

[0058] As illustrated in exemplary FIGS. 6A and 6B, connection management (CM) may include establishing and releasing a signaling connection between UE 100 and AMF 155 via the N1 interface. The signaling connection may be used to enable NAS signaling exchange between UE 100 and the core network. The signaling connection between UE 100 and AMF 155 may include both an AN signaling connection between UE 100 and (R)AN 105 (e.g., an RRC connection via 3GPP® access) and an N2 connection for UE 100 between the AN and AMF 155.

[0059] As illustrated in exemplary FIGS. 6A and 6B, two CM states may be used for the NAS signaling connection of UE 100 with AMF 155, CM idle 600, 620, and CM connected 610, 630. UE 100 in the CM idle 600 state may be in the RM registered 510 state and may not have a NAS signaling connection established with AMF 155 via N1. UE 100 may perform cell selection, cell reselection, PLMN selection, etc. UE 100 in the CM connected 610 state may have a NAS signaling connection with AMF 155 via N1.

[0060] In an exemplary embodiment, two CM states, CM idle 620 and CM connected 630, may be used for UE 100 at AMF 155.

[0061] In an example, the RRC inactive state may be applicable to the NG-RAN (e.g., applicable to NR and E-UTRA connected to the 5G CN). AMF 155 may provide assistance information to NG RAN 105 based on the network configuration to assist in the decision of NG RAN 105 as to whether UE 100 can be sent to the RRC inactive state. When UE 100 is in CM connected 610 with the RRC inactive state, UE 100 may resume the RRC connection in response to RAN105 paging to notify the network that it remains in the RAN105 notification area due to pending uplink data, mobile-originated signaling procedures.

[0062] In one example, NAS signaling connection management may include establishing and releasing a NAS signaling connection. The NAS signaling connection establishment function may be provided by UE100 and AMF155 to establish a NAS signaling connection for UE100 in the CM idle 600 state. The procedure for releasing the NAS signaling connection may be initiated by the 5G(R)AN105 node or AMF155.

[0063] In an embodiment, reachability management of UE100 may detect whether UE100 is reachable and provide the location of UE100 (e.g., an access node) to the network for reaching UE100. Reachability management may be performed by paging UE100 and location tracking of UE100. Location tracking of UE100 may include both registration area tracking of UE100 and reachability tracking of UE100. UE100 and AMF155 may negotiate the reachability characteristics of UE100 in the CM idle 600, 620 states during registration and registration update procedures.

[0064] In an embodiment, two reachability categories of UE100 may be negotiated between UE100 and AMF155 for the CM idle 600, 620 states. 1) Reachability of UE100 that enables mobile device termination data while UE100 is in the CM idle 600 mode. 2) Mobile-initiated connection dedicated (MICO) mode. 5GC may support a PDU connection service that provides the exchange of PDUs between UE100 and a data network identified by a DNN. The PDU connection service may be supported via a PDU session established in response to a request from UE100.

[0065] In an embodiment, a PDU session may support one or more PDU session types. The PDU session may be established (e.g., in response to a request from UE100), modified (e.g., in response to requests from UE100 and the 5GC), and / or released (e.g., in response to requests from UE100 and the 5GC) using NAS SM signaling exchanged between UE100 and SMF160 via N1. In response to a request from an application server, the 5GC may be able to trigger a specific application at UE100. Upon receiving the trigger, UE100 may send it to the identified application within UE100. The application identified in UE100 may establish a PDU session for a specific DNN.

[0066] In an embodiment, the 5G QoS model may support a QoS flow-based framework as illustrated in exemplary FIG. 7. The 5G QoS model may support both QoS flows that require a guaranteed flow bit rate and QoS flows that may not require a guaranteed flow bit rate. In an embodiment, the 5G QoS model may support reflective QoS. The QoS model may include flow mapping or packet marking at UPF110 (CN_UP) 110, AN105, and / or UE100. In an embodiment, packets may reach and / or be directed to the application / service layer 730 of UE100, UPF110 (CN_UP) 110, and / or AF145.

[0067] In an embodiment, a QoS flow can be the granularity of QoS differentiation in a PDU session. A QoS flow ID, QFI, can be used to identify a QoS flow within a 5G system. In an embodiment, user plane traffic having the same QFI within a PDU session can receive the same traffic transfer processing. The QFI can be carried in a encapsulation header on N3 and / or N9 (e.g., without any change to the end-to-end packet header). In an embodiment, the QFI can be applied to PDUs having different types of payloads. The QFI can be unique within a PDU session.

[0068] In an embodiment, the QoS parameters of a QoS flow can be provided as a QoS profile to (R)AN105 via N2 when the QoS flow is established in PDU session establishment, in QoS flow establishment, or whenever the user plane is activated and the NG-RAN is used. In an embodiment, a default QoS rule can be required for each PDU session. The SMF160 can assign a QFI to a QoS flow and derive QoS parameters from the information provided by the PCF135. In an embodiment, the SMF160 can provide the QFI to (R)AN105 together with a QoS profile including the QoS parameters of the QoS flow.

[0069] In an embodiment, a 5G QoS flow can be the granularity of QoS transfer processing in a 5G system. Traffic mapped to the same 5G QoS flow can receive the same transfer processing (e.g., scheduling policy, queue management policy, rate shaping policy, RLC configuration, etc.). In an embodiment, providing different QoS transfer processing may require separate 5G QoS flows.

[0070] In an embodiment, the 5G QoS indicator can be a scalar that can be used as a criterion for specific QoS transfer behaviors (e.g., packet loss rate, packet delay budget) provided to a 5G QoS flow. In an embodiment, the 5G QoS indicator can be implemented within an access network by a 5QI that refers to node-specific parameters (e.g., scheduling weights, admission thresholds, queue management thresholds, link layer protocol configurations, etc.) that can control QoS transfer processing.

[0071] In an embodiment, the 5GC may support edge computing and enable operators and third-party services to be hosted near the access point of the attached UE. The 5G core network may select a UPF 110 close to the UE 100 and perform traffic operations from the UPF 110 to the local data network via the N6 interface. In an embodiment, the selection and traffic operations may be based on subscription data of the UE 100, the location of the UE 100, information from the application function AF 145, policies, other relevant traffic rules, and the like. In one example, the 5G core network may expose network information and capabilities to the edge computing application function. The functional support for edge computing includes local routing where the 5G core network can select a UPF 110 and route user traffic to the local data network, traffic operations where the 5G core network can select traffic and route it to applications within the local data network, session and service continuity to enable UE 100 and application mobility, user plane selection and reselection based on, for example, input from the application function, network capability exposure where the 5G core network and the application function can provide information to each other via the NEf 125, QoS and charging where the PCF 135 can provide rules for QoS control and charging for traffic routed to the local data network, support for the local area data network where the 5G core network can provide support for connecting to the LADN in a specific area where the application is deployed, and the like.

[0072] An exemplary 5G system can be a 3GPP (registered trademark) system composed of a 5G access network 105, a 5G core network, and a UE 100, etc. The permitted NSSAI can be, for example, the NSSAI provided by the serving PLMN during the registration procedure, indicating the NSSAI permitted by the network for the UE 100 in the serving PLMN for the current registration area.

[0073] In an embodiment, the PDU connection service can provide the exchange of PDUs between the UE 100 and the data network. A PDU session can be an association between the UE 100 and a data network (DN) 115 and can provide a PDU connection service. The type of association can be IP, Ethernet (registered trademark), and / or unstructured.

[0074] The establishment of a user plane connection to a data network via a network slice instance can include performing RM procedures to select an AMF 155 that supports the required network slice and establishing one or more PDU sessions to the required data network via the network slice instance.

[0075] In an embodiment, the set of network slices for the UE 100 can change at any time while the UE 100 can be registered to the network and can be initialized by the network or the UE 100.

[0076] In an embodiment, a periodic registration update can be the re-registration of the UE 100 when a periodic registration timer expires. The required NSSAI can be the NSSAI that the UE 100 can provide to the network.

[0077] In an embodiment, a service-based interface can represent how a service set can be provided / exposed by a given NF.

[0078] In an embodiment, service continuity can be a user experience without service interruption, including cases where the IP address and / or anchor point can change. In an embodiment, session continuity can refer to the continuity of a PDU session. With respect to a PDU session of IP type session continuity, it can imply that the IP address is preserved during the lifetime of the PDU session. The uplink classifier can be a UPF110 function aimed at directing uplink traffic to the data network (DN) 115 based on filter rules provided by the SMF160.

[0079] In an embodiment, the 5G system architecture can support data connections and services such that deployment can use technologies such as network function virtualization and / or software-defined networking, for example. The 5G system architecture can leverage service-based interactions between control plane (CP) network functions when identified. In the 5G system architecture, separation of user plane (UP) functions from control plane functions can be considered. The 5G system can enable network functions to interact directly with other NFs as needed.

[0080] In an embodiment, the 5G system can reduce the dependency between the access network (AN) and the core network (CN). The architecture can include an integrated access independent core network having a common AN-CN interface that can integrate different 3GPP (registered trademark) and non-3GPP (registered trademark) access types.

[0081] In an embodiment, the 5G system can support a unified authentication framework and stateless NFs where computing resources are separated from storage resources, performance exposure, and simultaneous access to local and centralized services. To support access to low-latency services and local data networks, the UP function can be deployed close to the access network.

[0082] In an embodiment, the 5G system may support roaming with home routing traffic and / or local breakout traffic in the visited PLMN. An exemplary 5G architecture may be service-based, and the interaction between network functions may be represented in two ways. (1) A service-based representation (illustrated in exemplary FIG. 1) in which network functions within the control plane may enable other permitted network functions to access their services. This representation may also include point-to-point reference points as needed. (2) A reference point representation showing the interaction between NF services in network functions explained by point-to-point reference points (e.g., N11) between any two network functions.

[0083] In an embodiment, a network slice may include a core network control plane and user plane network functions, a 5G radio access network, an NN3IWF function for a non-3GPP (registered trademark) access network, etc. The network slice may vary depending on the supported functions and the implementation of the network functions. An operator may deploy multiple network slice instances that deliver the same characteristics for different UE groups, for example, to provide different committed services and / or to be customer-specific. The NSSF 120 may store mapping information between slice instance IDs and NF IDs (or NF addresses).

[0084] In an embodiment, the UE 100 may be simultaneously served by one or more network slice instances via the 5G-AN. In an embodiment, the UE 100 may be served by k network slices (e.g., k = 8, 16, etc.) at a time. Logically, the AMF 155 instance serving the UE 100 may belong to the network slice instance serving the UE 100.

[0085] In an embodiment, a PDU session may belong to one specific network slice instance per PLMN. In an embodiment, different network slice instances may not share a PDU session. Different slices may have slice-specific PDU sessions using the same DNN.

[0086] An S-NSSAI (Single Network Slice Selection Assistance Information) may identify a network slice. The S-NSSAI may include a slice / service type (SST) that may refer to the expected network slice behavior in terms of characteristics and services, and / or a slice differentiation factor (SD). The slice differentiation factor may be optional information that may complement the slice / service type to enable further differentiation for selecting a network slice instance from potentially multiple network slice instances that conform to the indicated slice / service type. In an embodiment, the same network slice instance may be selected using different S-NSSAIs. The CN part of the network slice instance serving UE100 may be selected by the CN.

[0087] In one example, the subscription data may include the S-NSSAI of the network slice to which UE100 subscribes. One or more S-NSSAIs may be marked as default S-NSSAIs. In an embodiment, k S-NSSAIs may be marked as default S-NSSAIs (e.g., k = 8, 16, etc.). In an embodiment, UE100 may register more than 8 S-NSSAIs.

[0088] In one example, UE100 may be configured by the HPLMN using the configured NSSAI per PLMN. Upon successful completion of the UE registration procedure, UE100 may obtain, from AMF155, the permitted NSSAI for this PLMN, which may include one or more S-NSSAIs.

[0089] In one example, the permitted NSSAI may be prioritized over the configured NSSAI for a PLMN. UE100 may use the S-NSSAI in the permitted NSSAI corresponding to the network slice for subsequent network slice selection procedures in the serving PLMN.

[0090] In an embodiment, establishing a user plane connection to a data network via a network slice instance may include performing RM procedures to select an AMF155 that may support the required network slice, and establishing one or more PDU sessions to the required data network via the network slice instance.

[0091] In an embodiment, when UE100 registers with a PLMN, if UE100 has a configured NSSAI or a permitted NSSAI for the PLMN, UE100 may provide the required NSSAI including the S-NSSAI corresponding to the slice that UE100 attempts to register to the RRC and NAS layer networks, a temporary user ID if assigned to the UE, etc. The required NSSAI may be the configured NSSAI, the permitted NSSAI, etc.

[0092] In an embodiment, when UE100 registers with a PLMN, if UE100 does not have a configured NSSAI or a permitted NSSAI for the PLMN, RAN105 may route NAS signaling from / to UE100 to / from the default AMF155.

[0093] In an embodiment, based on a local policy, a subscription change, and / or UE100 mobility, the network may change the set of permitted network slices to which UE100 is registered. In an embodiment, the network may perform the change during the registration procedure or trigger a notification to UE100 of a change to a supported network slice using the RM procedure (which may trigger the registration procedure). The network may provide UE100 with a new permitted NSSAI and a tracking area list.

[0094] In an embodiment, during the PLMN registration procedure, if the network determines, based on network slice aspects, that UE100 should be served by a different AMF155, the AMF155 that first received the registration request may redirect the registration request to another AMF155 via RAN105 or via direct signaling between the initial AMF155 and the target AMF155.

[0095] In an embodiment, the network operator may provision UE100 with a network slice selection policy (NSSP). The NSSP may include one or more NSSP rules.

[0096] In an embodiment, when the UE 100 has one or more PDU sessions established corresponding to a specific S-NSSAI, the UE 100 may route the user data of the application to one of the PDU sessions, except when other conditions of the UE 100 may prohibit the use of the PDU session. When the application provides a DNN, the UE 100 may consider the DNN to determine which PDU session to use. In an embodiment, when the UE 100 does not have a PDU session established with a specific S-NSSAI, the UE 100 may request a new PDU session corresponding to the S-NSSAI together with a DNN that may be provided by the application. In an embodiment, the RAN 105 may recognize the network slice used by the UE 100 in order to select appropriate resources for supporting network slicing within the RAN 105.

[0097] In an embodiment, when the UE 100 triggers the establishment of a PDU session, the AMF 155 may select the SMF 160 within the network slice instance based on the S-NSSAI, DNN, and / or other information, such as the subscription of the UE 100 and the local operator policy. The selected SMF 160 may establish a PDU session based on the S-NSSAI and DNN.

[0098] In one example, when the UE 100 recognizes or configures that privacy considerations may be applied to the NSSAI to support network control privacy of slice information for slices that the UE 100 may access, the UE 100 may not include the NSSAI in the NAS signaling, except when the UE 100 has a NAS security context, and the UE 100 may not include the NSSAI in the unprotected RRC signaling.

[0099] In one example, for a roaming scenario, the network slice specific network functions within the VPLMN and HPLMN can be selected based on the S-NSSAI provided by the UE100 during PDU session establishment. When a standardized S-NSSAI is used, the selection of slice specific NF instances can be performed by each PLMN based on the provided S-NSSAI. In an example, the VPLMN can map the S-NSSAI of the HPLMN to the S-NSSAI of the VPLMN based on a roaming contract (including, for example, the mapping to the default S-NSSAI of the VPLMN). In an example, the selection of slice specific NF instances in the VPLMN can be performed based on the S-NSSAI of the VPLMN. In an example, the selection of any slice specific NF instances in the HPLMN can be performed based on the S-NSSAI of the HPLMN.

[0100] As illustrated in the examples of FIGS. 8 and 9, the registration procedure can be performed by the UE100 to obtain permissions such as receiving services, enabling mobility tracking, enabling reachability, etc.

[0101] In one example, UE100 may send an AN message 805 (including AN parameters, RM-NAS registration request (registration type, SUCI or SUPI or 5G-GUTI, last visited TAI (if available), security parameters, requested NSSAI, mapping of the requested NSSAI, 5GC capabilities of UE100, PDU session state, PDU session to be reactivated, follow-on request, MICO mode preference, etc.)) to (R)AN105. In one example, in the case of NG-RAN, the AN parameters may include, for example, SUCI or SUPI or 5G-GUTI, selected PLMN ID, and requested NSSAI, etc. In one example, the AN parameters may include the establishment cause. The establishment cause may provide the reason for requesting the establishment of the RRC connection. In one example, the registration type may indicate whether UE100 wishes to perform an initial registration (i.e., UE100 is in the RM deregistered state), a mobility registration update (e.g., UE100 is in the RM registered state and starts the registration procedure due to mobility), a periodic registration update (e.g., UE100 is in the RM registered state and may start the registration procedure due to the expiration of the periodic registration update timer), or an emergency registration (e.g., UE100 is in a limited service state). In one example, when UE100 performs an initial registration to a PLMN that UE100 does not yet have a 5G-GUTI for (i.e., UE100 is in the RM deregistered state), UE100 may include its SUCI or SUPI in the registration request. SUCI may be included when the home network has prepared a public key to protect the SUPI in the UE. When UE100 receives a UE100 configuration update command indicating that UE100 needs to re-register and the 5G-GUTI is invalid, UE100 may perform an initial registration and may include the SUPI in the registration request message. Regarding emergency registration, the SUPI may be included if UE100 does not have a valid 5G-GUTI available, and the PET may be included when UE100 does not have the SUPI and does not have a valid 5G-GUTI. In other cases, the 5G-GUTI may be included and may indicate the last serving AMF155.If UE100 has already registered via non-3GPP (R) access within a PLMN different from the new PLMN for 3GPP (R) access (e.g., not a registered PLMN or a PLMN equivalent to the registered PLMN), then UE100 may not provide the 5G-GUTI assigned by AMF155 via 3GPP (R) access during the registration procedure via non-3GPP (R) access. If UE100 has already registered via 3GPP (R) access within a PLMN (e.g., a registered PLMN) different from the new PLMN for non-3GPP (R) access (i.e., not a registered PLMN or a PLMN equivalent to the registered PLMN), then UE100 may not provide the 5G-GUTI assigned by AMF155 via non-3GPP (R) access during the registration procedure via 3GPP (R) access. UE100 may provide the usage settings of the UE based on its configuration. In the case of initial registration or mobility registration update, UE100 ensures that the network can verify whether the S-NSSAI within the requested NSSAI is permitted based on the registered S-NSSAI, and may include the mapping of each S-NSSAI of the requested NSSAI of the configured NSSAI for the HPLMN, which can be the mapping of the requested NSSAI. If available, the last visited TAI may be included to assist AMF155 in generating the registration area for the UE. In an example, security parameters may be used for authentication and integrity protection. The requested NSSAI may indicate network slice selection assistance information. The PDU session state may indicate the PDU sessions previously established within the UE. When UE100 is connected to two AMF155 belonging to different PLMNs via 3GPP (R) access and non-3GPP (R) access, then the PDU session state may indicate the established PDU sessions of the current PLMN within the UE. The reactivated PDU session may be included to indicate the PDU session that UE100 intends to activate the UP connection.The PDU session corresponding to LADN may not be included in the PDU session that is reactivated when UE100 is outside the area where LADN is available. The follow-on request may be included when UE100 may have uplink signaling pending and may not include the PDU session in which UE100 is reactivated, or when the registration type may indicate that UE100 may wish to perform an emergency registration.

[0102] In one example, if the SUPI is included or the 5G-GUTI does not indicate a valid AMF155, the (R)AT105 may select the AMF155 (808) based on the available (R)AT and the requested NSSAI if available. When UE100 is in the CM connected state, the (R)AN105 may forward the registration request message to the AMF155 based on the UE's N2 connection. If the (R)AN105 may not select an appropriate AMF155, the registration request may be forwarded in the (R)AN105 to the configured AMF155 to perform the AMF155 selection 808.

[0103] In one example, the (R)AT105 may send an N2 message 810 (including N2 parameters, RM-NAS registration request (registration type, SUPI or 5G-GUTI, last visited TAI if available, security parameters, requested NSSAI, mapping of the requested NSSAI, 5GC capabilities of UE100, PDU session state, PDU session to be reactivated, follow-on request, and MICO mode preference, etc.) to the new AMF155. In one example, when NG-RAN is used, the N2 parameters may include the selected PLMN ID, location information, cell identification information, and RAT type related to the cell where UE100 is camping. In one example, when NG-RAN is used, the N2 parameters may include the establishment cause.

[0104] In one example, the new AMF155 may send a Namf_Communication_UEContextTransfer (Completion Registration Request) 815 to the previous AMF155. In one example, if the 5G-GUTI of the UE is included in the registration request and the serving AMF155 is changed from the last registration procedure, the new AMF155 may call a Namf_Communication_UEContextTransfer service operation 815 for the previous AMF155 that includes a Completion Registration Request IE that may be integrity protected to request the SUPI and MM context of the UE. The previous AMF155 may use the integrity protected Completion Registration Request IE to verify whether the context transfer service operation call corresponds to the requested UE100. In an embodiment, the previous AMF155 may transfer event subscription information by each NF consumer regarding the UE to the new AMF155. In one example, if the UE100 identifies itself using the PEI, the SUPI request may be skipped.

[0105] In one example, the previous AMF155 may send a response 815 for Namf_Communication_UEContextTransfer (SUPI, MM context, information of SMF160, PCF ID) to the new AMF155. In one example, the previous AMF155 may respond to the new AMF155 for a Namf_Communication_UEContextTransfer call by including the SUPI and MM context of the UE. In one example, if the previous AMF155 holds information about the established PDU session, the previous AMF155 may include SMF160 information including the S-NSSAI, identification information of SMF160, and the PDU session ID. In one example, if the previous AMF155 holds information about the active NGAP UE-TNLA association belonging to the N3IWF, the previous AMF155 may include information about the NGAP UE-TNLA association.

[0106] In one example, if the SUPI is not provided by UE100 and not obtained from the previous AMF155, the identification request procedure 820 can be initiated by the AMF155 that sends an identification information request message to the UE100 requesting the SUCI.

[0107] In one example, UE100 can respond with an identification information response message 820 containing the SUCI. UE100 can derive the SUCI using the prepared public key of the HPLMN.

[0108] In one example, the AMF155 can decide to initiate the authentication 825 of UE100 by invoking the AUSF150. The AMF155 can select the AUSF150 based on the SUPI or SUCI. In one example, if the AMF155 is configured to support emergency registration for an unauthenticated SUPI and UE100 indicates a registration type of emergency registration, the AMF155 can skip the authentication and security setup, or the AMF155 can commit that the authentication may fail and the registration procedure can continue.

[0109] In one example, the authentication 830 can be performed by the Nudm_UEAuthenticate_Get operation. The AUSF150 can discover the UDM140. If the AMF155 provides the SUCI to the AUSF150, the AUSF150 can return the SUPI to the AMF155 after successful authentication. In an embodiment, when network slicing is used, the AMF155 can determine whether the registration request needs to be re-routed where the initial AMF155 points to the AMF155. In an embodiment, the AMF155 can initiate the NAS security function. In an embodiment, upon completion of the NAS security function setup, the AMF155 can initiate the NGAP procedure to enable the 5G-AN to use the NGAP procedure for the confidentiality protection procedure by the UE. In an embodiment, the 5G-AN can store the security context and can send an affirmative response to the AMF155. The 5G-AN can use the security context to protect the messages exchanged with the UE.

[0110] In one example, the new AMF155 may send Namf_Communication_RegistrationCompleteNotify835 to the previous AMF155. If the AMF155 changes, the new AMF155 may notify the previous AMF155 that the registration of the UE100 within the new AMF155 can be completed by invoking the Namf_Communication_RegistrationCompleteNotify service operation. If the authentication / security procedure fails, the registration may be rejected, and the new AMF155 may invoke the Namf_Communication_RegistrationCompleteNotify service operation using a rejection indication reason code for the previous AMF155. The previous AMF155 may continue as if it had not received any UE100 context transfer service operations at all. If one or more of the S-NSSAIs used in the previous registration area may not be served within the target registration area, the new AMF155 may determine which PDU sessions may be supported in the new registration area. The new AMF155 may invoke a Namf_Communication_RegistrationCompleteNotify service operation for the previous AMF155 that includes the rejected PDU session ID and the cause of the rejection (e.g., the S-NSSAI is no longer available). The new AMF155 may modify the PDU session state accordingly. The previous AMF155 may notify the corresponding SMF160 to locally release the UE's SM context by invoking the Nsmf_PDUSession_ReleaseSMContext service operation.

[0111] In one example, the new AMF 155 may send an ID request / response 840 (e.g., PEI) to the UE 100. If the PEI is not provided by the UE 100 and not obtained from a previous AMF 155, the identification request procedure may be initiated by the AMF 155 that sends an identification information request message to the UE 100 to obtain the PEI. The PEI may be encrypted and transferred, except when the UE 100 performs an emergency registration and may not be authenticated. For emergency registration, the UE 100 may include the PEI in the registration request.

[0112] In one example, the new AMF 155 may initiate an ME identification information check 845 by invoking an N5g-eir_EquipmentIdentityCheck_Get service operation 845.

[0113] In one example, the new AMF 155 may select the UDM 140 based on the SUPI (905). The UDM 140 may select a UDR instance. In an embodiment, the AMF 155 may select the UDM 140.

[0114] In one example, when the AMF155 has changed from the last registration procedure, or when the UE100 provides a SUPI that may not refer to a valid context of the AMF155, or when the UE100 registers with the same AMF155 that has already been registered for non-3GPP (registered trademark) access (the UE100 may be registered via non-3GPP (registered trademark) access and start a registration procedure to add 3GPP (registered trademark) access), the new AMF155 may register with the UDM140 using Nudm_UECM_Registration910 and may register in such a way that it is notified when the UDM140 can deregister the AMF155. The UDM140 may store the AMF155 identification information associated with the access type and may not need to remove the AMF155 identification information associated with other access types. The UDM140 may store the information provided at the time of registration of the UDR by Nudr_UDM_Update. In one example, the AMF155 may obtain access and mobility subscription data and SMF160 selection subscription data using Nudm_SDM_Get915. The UDM140 may obtain this information from the UDR by Nudr_UDM_Query (access and mobility subscription data). After a normal response is received, the AMF155 may register using Nudm_SDM_Subscribe920 to be notified when the requested data can be modified. The UDM140 may register with the UDR by Nudr_UDM_Subscribe. The GPSI may be provided to the AMF155 in the subscription data from the UDM140 if the GPSI is available within the subscription data of the UE100. In an embodiment, the new AMF155 may provide the access type serving the UE100 to the UDM140, and the access type may be set to 3GPP (registered trademark) access. The UDM140 may store the associated access type with the serving AMF155 in the UDR by Nudr_UDM_Update. After obtaining the mobility subscription data from the UDM140, the new AMF155 may create an MM context for the UE100.In one example, when the UDM 140 stores the associated access type together with the serving AMF 155, the UDM 140 may initiate a Nudm_UECM_DeregistrationNotification921 to the previous AMF 155 corresponding to the 3GPP (registered trademark) access. The previous AMF 155 may remove the UE's MM context. If the reason for the serving NF removal indicated by the UDM 140 is initial registration, the previous AMF 155 may call the Namf_EventExposure_Notify service operation for all the associated SMFs 160 of the UE 100 to notify that the UE 100 has been deregistered from the previous AMF 155. The SMF 160 may release the PDU session when obtaining this notification. In one example, the previous AMF 155 may use Nudm_SDM_unsubscribe922 to unsubscribe from the UDM 140 regarding the subscription data.

[0115] In one example, when the AMF 155 decides to initiate PCF 135 communication, for example, if the AMF 155 has not yet obtained the access and mobility policy for the UE 100 or the access and mobility policy of the AMF 155 is no longer valid, the AMF 155 may select the PCF 135 (925). If the new AMF 155 receives the PCF ID from the previous AMF 155 and successfully contacts the PCF 135 identified by the PCF ID, the AMF 155 may select the (V-)PCF identified by the PCF ID. If there is a possibility that the PCF 135 identified by the PCF ID may not be used (for example, no response from the PCF 135) or if the PCF ID received from the previous AMF 155 does not exist, the AMF 155 may select the PCF 135 (925).

[0116] In one example, the new AMF 155 may perform a policy association establishment 930 during the registration procedure. When the new AMF 155 contacts the PCF 135 identified by the (V-)PCF ID received during the mobility of the AMF 155, the new AMF 155 may include the PCF-ID within the Npcf_AMPolicyControl Get operation. When the AMF 155 notifies the PCF 135 of mobility constraints (e.g., the location of the UE 100) for adjustment, or when the PCF 135 updates the mobility constraints themselves due to some conditions (e.g., the application in use, time and date), the PCF 135 may provide the updated mobility constraints to the AMF 155.

[0117] In one example, the PCF 135 may invoke the Namf_EventExposure_Subscribe service operation 935 for UE 100 event subscription.

[0118] In one example, the AMF 155 may send Nsmf_PDUSession_UpdateSMContext936 to the SMF 160. In an embodiment, the AMF 155 may call Nsmf_PDUSession_UpdateSMContext if the PDU session to be reactivated is included within the registration request. The AMF 155 may send an Nsmf_PDUSession_UpdateSMContext request to the SMF 160 associated with the PDU session to activate the user plane connection of the PDU session. The SMF 160 may decide, for example, to trigger the insertion, removal, or change of the PSA intermediate UPF 110. When the insertion, removal, or rearrangement of the intermediate UPF 110 is performed for a PDU session not included within the PDU session to be reactivated, the procedure may be performed without N11 and N2 interactions to update the N3 user plane between the (R)AN 105 and the 5GC. The AMF 155 may call the Nsmf_PDUSession_ReleaseSMContext service operation for the SMF 160 if any PDU session state indicates that it has been released at the UE 100. The AMF 155 may call the Nsmf_PDUSession_ReleaseSMContext service operation for the SMF 160 to release any network resources associated with the PDU session.

[0119] In one example, the new AMF 155155 may send the mobility request 940 of the N2 AMF 155 to the N3IWF. If the AMF 155 is changed, the new AMF 155 may create an association of the NGAP UE 100 for the N3IWF to which the UE 100 is connected. In one example, the N3IWF may respond to the new AMF 155 using the N2 AMF 155 mobility response 940.

[0120] In one example, the new AMF 155 may send a registration commitment 955 (including 5G-GUTI, registration area, mobility constraints, PDU session state, permitted NSSAI, [mapping of permitted NSSAI], periodic registration update timer, LADN information and steered MICO mode, IMS voice over PS session support indication, emergency service support indicator, etc.) to the UE 100. In one example, the AMF 155 may send a registration commitment message to the UE 100 indicating that the registration request has been committed. The 5G-GUTI may be included when the AMF 155 allocates a new 5G-GUTI. When the AMF 155 allocates a new registration area, it may send the registration area to the UE 100 via the registration commitment message 955. If the registration area is not included in the registration commitment message, the UE 100 may consider the previous registration area as valid. In an embodiment, the mobility constraints may be included when the mobility constraints may apply to the UE 100 and the registration type may not be an emergency registration. The AMF 155 may indicate to the UE 100 the established PDU sessions within the PDU session state. The UE 100 may locally remove any internal resources associated with PDU sessions that are not marked as established within the received PDU session state. In an embodiment, when the UE 100 is connected to two AMF 155s belonging to different PLMNs via 3GPP (registered trademark) access and non-3GPP (registered trademark) access, then the UE 100 may locally remove any internal resources associated with the current PLMN's PDU sessions that are not marked as established within the received PDU session state. If the PDU session state information was within the registration request, the AMF 155 may indicate the PDU session state to the UE. The mapping of the permitted NSSAI may be the mapping of each S-NSSAI of the permitted NSSAI to the S-NSSAI of the configured NSSAI for the HPLMN. The AMF 155 may include in the registration commitment message 955 the LADN information for the LADN that is available within the registration area determined by the AMF of the UE. If the UE 100 includes the MICO mode in the request, the AMF 155 may respond as to whether the MICO mode may be used.The AMF 155 can set the IMS voice over PS session support indication. In an embodiment, to set the IMS voice over PS session support indication, the AMF 155 can perform UE / RAN radio information and compatibility requirement procedures to check the compatibility of the UE 100 and RAN radio performance related to IMS voice over PS. In an embodiment, the emergency service support indicator can notify the UE 100 that the emergency service is supported. For example, the UE 100 can request a PDU session for the emergency service. In one example, the handover constraint list and UE-AMBR can be provided to the NG-RAN by the AMF 155.

[0121] In one example, the UE 100 can send a registration complete message 960 to the new AMF 155. In one example, the UE 100 can send a registration complete message 960 to the AMF 155 and affirmatively respond that a new 5G-GUTI can be allocated. In one example, if the information about the PDU session to be reactivated is not included in the registration request, the AMF 155 can release the signaling connection with the UE 100. In an embodiment, when a follow-on request is included in the registration request, the AMF 155 may not release the signaling connection after the completion of the registration procedure. In one example, if the AMF 155 recognizes that some signaling is pending at the AMF 155 or between the UE 100 and the 5GC, the AMF 155 may not release the signaling connection after the completion of the registration procedure.

[0122] As illustrated in the exemplary FIGS. 10 and 11, a service request procedure, e.g., a service request procedure triggered by UE 100, may be used by a UE 100 in CM idle state to request the establishment of a secure connection to the AMF 155. FIG. 11 is a continuation of FIG. 10 illustrating the service request procedure. The service request procedure may be used to activate a user plane connection for an established PDU session. The service request procedure may be triggered by the UE 100 or the 5GC and may be used when the UE 100 is in CM idle and / or CM connected, and may enable selectively activating user plane connections for some of the established PDU sessions.

[0123] In one example, a UE 100 in CM IDLE state may initiate a service request procedure and transmit an uplink signaling message, user data, etc. as a response to a network paging request, etc. In one example, after receiving a service request message, the AMF 155 may perform authentication. In one example, after establishing a signaling connection to the AMF 155, the UE 100 or the network may transmit a signaling message, e.g., a PDU session establishment, from the UE 100 to the SMF 160 via the AMF 155.

[0124] In one example, for any service request, the AMF 155 may respond with a service commitment message to synchronize the PDU session state between the UE 100 and the network. If the service request may not be committed by the network, the AMF 155 may respond with a service rejection message to the UE 100. The service rejection message may include an indication that requires the UE 100 to perform a registration update procedure or may cause a code. In one example, for a service request due to user data, the network may take further measures if the activation of the user plane connection may not succeed. In the exemplary FIGS. 10 and 11, more than one UPF, e.g., the old UPF 110-2 and the PDU session anchor PSA UPF 110-3, may be involved.

[0125] In one example, the UE 100 may send an AN message to the (R)AN 105 that includes AN parameters, mobility management (MM) NAS service requests 1005 (e.g., a list of PDU sessions to be activated, a list of permitted PDU sessions, security parameters, PDU session states, etc.). In one example, the UE 100 may provide a list of PDU sessions to be activated when the UE 100 may reactivate a PDU session. The list of permitted PDU sessions may be provided by the UE 100 when the service request may be a paging or NAS notification response and may identify PDU sessions that may be transferred or associated with the access where the service request may be sent. In one example, for the NG-RAN, the AN parameters may include the selected PLMN ID and the establishment cause. The establishment cause may provide the reason for requesting the establishment of an RRC connection. The UE 100 may send a NAS service request message to the RAN 105 encapsulated within an RRC message and directed to the AMF 155.

[0126] In one example, when the service request may be triggered for user data, the UE 100 may use the list of PDU sessions to be activated to identify the PDU sessions for which the UP connection is to be activated within the NAS service request message. When the service request may be triggered for signaling, the UE 100 may not identify any PDU sessions. If this procedure may be triggered for a paging response and / or the UE 100 may have user data to be transferred simultaneously, the UE 100 may identify the PDU sessions for which the UP connection may be activated within the MM NAS service request message by the list of PDU sessions to be activated.

[0127] In one example, when a service request via 3GPP (registered trademark) access can be triggered in response to paging indicating non-3GPP (registered trademark) access, the NAS service request message may identify a list of PDU sessions associated with non-3GPP (registered trademark) access that can be reactivated via 3GPP (registered trademark) within the list of permitted PDU sessions. In one example, the PDU session state may indicate the PDU sessions available within UE100. In one example, UE100 may not trigger service request procedures for a PDU session corresponding to LADN when UE100 may be outside the area of availability of LADN. UE100 may not identify such a PDU session within the list of PDU sessions to be activated when the service request can be triggered for other reasons.

[0128] In one example, (R)AN105 may send an N2 message 1010 (e.g., a service request) including N2 parameters, an MM NAS service request, etc. to AMF155. AMF155 may reject the N2 message if it may not be able to process the service request. In one example, when NG-RAN can be used, the N2 parameters may include a 5G-GUTI, a selected PLMN ID, location information, RAT type, establishment cause, etc. In one example, the 5G-GUTI may be obtained in an RRC procedure and (R)AN105 may select AMF155 according to the 5G-GUTI. In one example, the location information and the RAT type may be related to the cell where UE100 may camp. In one example, based on the PDU session state, AMF155 may initiate PDU session release procedures in the network for PDU sessions that may be indicated as not being available by UE100 with respect to the PDU session ID.

[0129] In one example, if the service request was not sent with integrity protection or the integrity protection verification fails, AMF155 may initiate NAS authentication / security procedures 1015.

[0130] In one embodiment, when UE100 triggers a service request to establish a signaling connection, if the establishment of the signaling connection is successful, UE100 and the network may exchange NAS signaling.

[0131] In one example, AMF155 may send a PDU session update context request 1020, such as an Nsmf_PDUSession_UpdateSMContext request, to SMF160, which includes a PDU session ID, a cause, location information of UE100, an access type, etc.

[0132] In one example, the Nsmf_PDUSession_UpdateSMContext request may be invoked by AMF155 if UE100 can identify the PDU session activated within the NAS service request message. In one example, the Nsmf_PDUSession_UpdateSMContext request may be triggered by SMF160, and the PDU session identified by UE100 may be correlated with a PDU session ID other than the one that triggers the procedure. In one example, the Nsmf_PDUSession_UpdateSMContext request may be triggered by SMF160, and the current location of UE100 may be outside the validity area for the N2 information provided by SMF160 during the network-triggered service request procedure. AMF155 may not send the N2 information provided by SMF160 during the network-triggered service request procedure.

[0133] In one example, AMF155 may determine the PDU session to be activated and send an Nsmf_PDUSession_UpdateSMContext request to SMF160 associated with the PDU session together with a cause set to indicate the establishment of user plane resources for the PDU session.

[0134] In one example, the procedure may be triggered in response to paging indicating non-3GPP (registered trademark) access, and if the PDU session for which the UE 100 is paged may not be included in the list of permitted PDU sessions provided by the UE 100, the AMF 155 may notify the SMF 160 that the user plane for the PDU session may not be reactivated. The service request procedure may succeed without reactivating the user plane of any PDU session, and the AMF 155 may notify the UE 100.

[0135] In one example, the PDU session ID may correspond to the LADN, and if the SMF 160 may determine, based on the UE 100 location report from the AMF 155, that the UE 100 may be outside the area of availability of the LADN, the SMF 160 may determine (based on local policy) to maintain the PDU session, may reject the activation of the user plane connection for the PDU session, and may notify the AMF 155. In one example, if the procedure may be triggered by a network-triggered service request, the SMF 160 may notify the UPF 110 that initiated the data notification to discard the downlink data for the PDU session and / or not provide further data notification messages. The SMF 160 may respond to the AMF 155 with an appropriate rejection cause, and the user plane activation of the PDU session may be stopped.

[0136] In one example, the PDU session ID may correspond to the LADN, and if the SMF 160 may determine, based on the UE 100 location report from the AMF 155, that the UE 100 may be outside the area of availability of the LADN, the SMF 160 may determine (based on local policy) to release the PDU session. The SMF 160 may locally release the PDU session and may notify the AMF 155 that the PDU session may be released. The SMF 160 may respond to the AMF 155 with an appropriate rejection cause, and the user plane activation of the PDU session may be stopped.

[0137] In one embodiment, when the activation of the PDU session's UP can be committed by the SMF160, based on the location information received from the AMF155, the SMF160 checks the criteria for the selection 1025 of the UPF110 (for example, slice separation requirements, slice coexistence requirements, the dynamic load of the UPF110, the relative static capacity of the UPF110 among UPFs supporting the same DNN, the location of the UPF110 available at the SMF160, the location information of the UE100, the capabilities of the UPF110, and the functions required for a specific UE100 session). In one example, a suitable UPF110 can be selected by matching the functions and features required for the UE100, the DNN, the PDU session type (for example, IPv4, IPv6, Ethernet (registered trademark) type or unstructured type), and, if applicable, the static IP address / prefix, the SSC mode selected for the PDU session, the UE100 subscription profile of the UDM140, the DNAI included in the PCC rule, the local operator policy, the S-NSSAI, the access technology used by the UE100, the logical topology of the UPF110, etc., continue to use the current UPF, when the UE100 moves out of the service area of the UPF110 already connected to the (R)AN105, a new intermediate UPF110 can be selected (or an intermediate UPF110 can be added / removed), but maintain the UPF acting as the PDU session anchor, trigger the re-establishment of the PDU session to implement the relocation / reattribution of the UPF110 acting as the PDU session anchor, for example, determine to perform one or more of the cases where the UE100 has moved out of the service area of the anchor UPF110 connected to the RAN105.

[0138] In one example, the SMF 160 may send the N4 session establishment request 1030 to the UPF 110 (e.g., a new intermediate UPF 110). In one example, when the SMF 160 may select a new UPF 110 to act as the intermediate UPF 110-2 for a PDU session, or when the SMF 160 may select to insert an intermediate UPF 110 for a PDU session that may not have an intermediate UPF 110-2, the N4 session establishment request 1030 message may be sent to the new UPF 110, providing packet detection, data transfer, enforcement, and reporting rules installed at the new intermediate UPF. The PDU session anchor address specification information (on N9) for this PDU session may be provided to the intermediate UPF 110-2.

[0139] In one example, when the new UPF 110 is selected by the SMF 160 to replace the previous (intermediate) UPF 110-2, the SMF 160 may include a data transfer indication. The data transfer indication may indicate to the UPF 110 that the second tunnel endpoint may be reserved for buffered DL data from the previous I-UPF.

[0140] In one example, the new UPF 110 (intermediate) may send an N4 session establishment response message 1030 to the SMF 160. If the UPF 110 may allocate CN tunnel information, the UPF 110 may provide the DL CN tunnel information and the UL CN tunnel information (e.g., CN N3 tunnel information) for the UPF 110 acting as the PDU session anchor to the SMF 160. If a data transfer indication may be received, the new (intermediate) UPF 110 acting as the N3 endpoint may send the DL CN tunnel information for the previous (intermediate) UPF 110-2 to the SMF 160. The SMF 160 may start a timer to release the resources of the previous intermediate UPF 110-2.

[0141] In one example, if the SMF160 can select a new intermediate UPF110 for the PDU session or can remove the previous I-UPF110-2, the SMF160 may send an N4 session modification request message 1035 to the PDU session anchor, the PSA UPF110-3, and provide data transfer indication and DL tunnel information from the new intermediate UPF110.

[0142] In one example, if a new intermediate UPF110 can be added for the PDU session, the (PSA) UPF110-3 may start sending DL data to the new I-UPF110 as indicated in the DL tunnel information.

[0143] In one example, if a service request can be triggered by the network and the SMF160 removes the previous I-UPF110-2 and may not replace the previous I-UPF110-2 with the new I-UPF110, the SMF160 may include a data transfer indication in the request. The data transfer indication may indicate to the (PSA) UPF110-3 that the second tunnel endpoint may be reserved for the buffered DL data from the previous I-UPF110-2. In this case, the PSA UPF110-3 may start buffering the DL data that it can receive simultaneously from the N6 interface.

[0144] In one example, the PSA UPF110-3 (PSA) may send an N4 session modification response 1035 to the SMF160. In one example, if a data transfer indication can be received, the PSA UPF110-3 may become the N3 termination point and send the DL CN tunnel information for the previous (intermediate) UPF110-2 to the SMF160. The SMF160 may start a timer to release the resources of the previous intermediate UPF110-2 if there is one.

[0145] In one example, SMF160 may send an N4 session modification request 1045 to the previous UPF110-2 (which may include, for example, the new UPF110 address, the DL tunnel ID of the new UPF110, etc.). In one example, when a service request may be triggered by the network and / or when SMF160 may remove the previous (intermediate) UPF110-2, SMF160 may send an N4 session modification request message to the previous (intermediate) UPF110-2 and may provide DL tunnel information for the buffered DL data. When SMF160 may allocate a new I-UPF110, the DL tunnel information is from the new (intermediate) UPF110 and may act as an N3 termination point. When there is a possibility that SMF160 may not allocate a new I-UPF110, the DL tunnel information may be from a new (intermediate) UPF110 (PSA) 110-3 that acts as an N3 termination point. SMF160 may start a timer to monitor the transfer tunnel. In one example, the previous (intermediate) UPF110-2 may send an N4 session modification response message to SMF160.

[0146] In one example, when the I-UPF110-2 may be relocated and a transfer tunnel is established for the new I-UPF110, the previous (intermediate) UPF110-2 may transfer its buffered data to the new (intermediate) UPF110 that acts as an N3 termination point. In one example, when the previous I-UPF110-2 may be removed and there is a possibility that the new I-UPF110 may not be allocated to the PDU session and a transfer tunnel may be established for the UPF110(PSA) 110-3, the previous (intermediate) UPF110-2 may transfer its buffered data to the UPF110(PSA) 110-3 that acts as an N3 termination point.

[0147] In one example, when receiving an Nsmf_PDUSession_UpdateSMContext request that includes a cause, such as establishing user plane resources, SMF160 may send an N11 message 1060, such as an Nsmf_PDUSession_UpdateSMContext response (N1 SM container (PDU session ID, PDU session re - establishment indication), N2 SM information (PDU session ID, QoS profile, CN N3 tunnel information, S - NSSAI), cause) to AMF155. SMF160 may determine whether UPF110 relocation can be performed based on UE100 location information, UPF110 service area, and operator policy. In one example, for a PDU session for which SMF160 may determine that it is served by the current UPF110, such as a PDU session anchor or an intermediate UPF, SMF160 may generate N2 SM information and send an Nsmf_PDUSession_UpdateSMContext response 1060 to AMF155 to establish the user plane. The N2 SM information may include information that AMF155 may provide to RAN105. In one example, for a PDU session for which SMF160 may determine that relocation of UPF110 is required for the PDU session anchor UPF, SMF160 may reject the activation of the UP of the PDU session by sending an Nsmf_PDUSession_UpdateSMContext response that may include an N1 SM container to UE100 via AMF155. The N1 SM container may include the corresponding PDU session ID and PDU session re - establishment indication.

[0148] When the SMF 160 receives the Namf_EventExposure_Notify from the AMF 155 and includes an indication that the UE 100 is reachable, if the SMF 160 has DL data in hold, the SMF 160 may call the Namf_Communication_N1N2MessageTransfer service operation for the AMF 155 to establish the user plane for the PDU session. In one example, the SMF 160 may resume sending a DL data notification to the AMF 155 in the case of DL data.

[0149] In one example, the SMF 160 may include a cause in the Nsmf_PDUSession_UpdateSMContext response to reject the activation of the UP of the PDU session by sending a message to the AMF 155 if the PDU session may correspond to a LADN, the UE 100 may be outside the area of availability of the LADN, or the AMF 155 may notify the SMF 160 that the UE 100 may be reachable for a regulated priority service and the PDU session to be activated may not be for a regulated priority service, or the SMF 160 may determine to perform a PSA UPF 110-3 relocation for the requested PDU session.

[0150] In one example, AMF155 may send an N2 request message 1065 (e.g., N2 SM information received from SMF160, security context, AMF155 signaling connection ID, handover restriction list, MM NAS service commitment, list of recommended cell / TA / NG-RAN node identifiers) to (R)AN105. In one example, RAN105 may store the security context, AMF155 signaling connection ID, QoS information for QoS flows of PDU sessions that may be activated, and the N3 tunnel ID within the RAN105 context of UE100. In one example, the MM NAS service commitment may include the PDU session state within AMF155. If the activation of the UP of the PDU session may be rejected by SMF160, the MM NAS service may include the PDU session ID and the reason why the user plane resources may not be activated (e.g., LADN is not available). The local PDU session release during the session request procedure may be indicated to UE100 via the session state.

[0151] In one example, if there are multiple PDU sessions with multiple SMF160s, AMF155 may not wait for responses from all SMF160s before sending the N2 SM information to UE100. AMF155 may wait for all responses from SMF160s before sending the MM NAS service commitment message to UE100.

[0152] In one example, if the AMF 155 can be triggered for PDU session user plane activation procedures, it may include at least one N2 SM information from the SMF 160. If present, the AMF 155 may send additional N2 SM information from the SMF 160 within a separate N2 message (e.g., N2 tunnel setup request). Alternatively, if multiple SMFs 160 may be involved, the AMF 155 may send one N2 request message to the (R)AN 105 after all Nsmf_PDUSession_UpdateSMContext response service operations from all SMFs 160 associated with the UE 100 have been received. In such a case, the N2 request message may include the N2 SM information received with each of the Nsmf_PDUSession_UpdateSMContext response and the PDU session ID, such that the AMF 155 can associate the response with the relevant SMF 160.

[0153] In one example, if the RAN 105 (e.g., NG RAN) node can provide a list of recommended cell / TA / NG-RAN node identifiers during the AN release procedure, the AMF 155 may include the information from the list in the N2 request. The RAN 105 may use this information to allocate the RAN 105 notification area when the RAN 105 determines to enable the RRC inactive state for the UE 100.

[0154] During PDU session establishment procedures where the UE 100 may be using a PDU session related to a latency-sensitive service, the AMF 155 may receive an indication from the SMF 160 for any of the PDU sessions established for the UE 100, and if the AMF 155 receives the indication from the UE 100 that can support CM connection in the RRC inactive state, the AMF 155 may include UE's RRC inactive support information. In one example, the AMF 155 based on the network configuration may include UE's RRC inactive support information.

[0155] In one example, (R)AN105 may send a message to UE100 to perform an RRC connection reconfiguration 1070 with UE100, depending on the QoS information for all QoS flows of the PDU session for which the UP connection can be activated and the data radio bearer. In one example, user plane security may be established.

[0156] In one example, when the N2 request may include an MM NAS service commitment message, RAN105 may transfer the MM NAS service commitment to UE100. UE100 may locally delete the context of the PDU session that may not be available in the 5GC.

[0157] In one example, when N1 SM information may be sent to UE100 and may indicate that some PDU sessions may be re-established, UE100 may initiate a PDU session re-establishment for the PDU sessions that may be re-established after the service request procedure may be completed.

[0158] In one example, after user plane radio resources may be configured, uplink data from UE100 may be transferred to RAN105. RAN105 (e.g., NG-RAN) may send the uplink data to the provided UPF110 address and tunnel ID.

[0159] In one example, (R)AN105 may send an N2 request Ack1105 (e.g., N2 SM information (AN tunnel information, list of committed QoS flows for the PDU session for which the UP connection is activated, list of rejected QoS flows for the PDU session for which the UP connection is activated)) to AMF155. In one example, the N2 request message may include N2 SM information, e.g., AN tunnel information. RAN105 may respond with N2 SM information including a separate N2 message (e.g., N2 tunnel setup response). In one example, if multiple N2 SM information is included within the N2 request message, the N2 request Ack may include the multiple N2 SM information and information to enable AMF155 to associate the response with the relevant SMF160.

[0160] In one example, AMF155 may send an Nsmf_PDUSession_UpdateSMContext request 1110 (N2 SM information (AN tunnel information), RAT type) to SMF160 for each PDU session. If AMF155 may receive N2 SM information (one or more) from RAN105, AMF155 may forward the N2 SM information to the relevant SMF160. If the time zone of UE100 may change compared to the time zone of UE100 last reported, AMF155 may include the UE100 time zone IE within the Nsmf_PDUSession_UpdateSMContext request message.

[0161] In one example, when dynamic PCC is deployed, SMF160 may initiate a notification regarding new location information to PCF135 (if registered) by invoking an event exposure notification operation (e.g., Nsmf_EventExposure_Notify service operation). PCF135 may provide an updated policy by invoking a policy control update notification message 1115 (e.g., Npcf_SMPolicyControl_UpdateNotify operation).

[0162] In one example, when the SMF160 can select a new UPF110 to act as the intermediate UPF110 for the PDU session, the SMF160 can initiate an N4 session modification procedure 1120 for the new I-UPF110 and can provide AN tunnel information. The downlink data from the new I-UPF110 can be transferred to the RAN105 and the UE100. In one example, the UPF110 can send an N4 session modification response 1120 to the SMF160. In one example, the SMF160 can send an Nsmf_PDUSession_UpdateSMContext response 1140 to the AMF155.

[0163] In one example, when a transfer tunnel can be established for the new I-UPF110 and when the timer SMF160 set for the transfer tunnel can expire, the SMF160 can send an N4 session modification request 1145 to the new (intermediate) UPF110 acting as the N3 termination point to release the transfer tunnel. In one example, the new (intermediate) UPF110 can send an N4 session modification response 1145 to the SMF160. In one example, the SMF160 can send an N4 session modification request 1150, or an N4 session release request, to the PSA UPF110-3. In one example, when the SMF160 can continue to use the previous UPF110-2, the SMF160 can send an N4 session modification request 1155 and provide AN tunnel information. In one example, when the SMF160 can select a new UPF110 to act as the intermediate UPF110 and there is a possibility that the previous UPF110-2 is not the PSA UPF110-3, the SMF160 can start resource release after the timer expires by sending an N4 session release request (release cause) to the previous intermediate UPF110-2.

[0164] In one example, a previous (intermediate) UPF 110-2 may send an N4 session modification response or an N4 session release response 1155 to the SMF 160. The previous UPF 110-2 may acknowledge with an N4 session modification response or an N4 session release response message to confirm the modification or release of resources. The AMF 155 may call the Namf_EventExposure_Notify service operation to notify mobility-related events to an NF that may have registered an event after this procedure may be completed. In one example, the AMF 155 may notify the SMF 160 for a UE 100 when the SMF 160 moves into or out of a target area, and when the current location of the UE indicates that the UE is moving into or out of a registered area of interest, or when the SMF 160 has registered an LADN DNN and the UE 100 may move into or out of an area where the LADN is available, or when the UE 100 may be in MICO mode and the AMF 155 has notified the SMF 160 of the UE 100 that is unreachable, and the SMF 160 may not have sent a DL data notification to the AMF 155 and the AMF 155 may inform the SMF 160 that the UE 100 is reachable, or when the SMF 160 has registered the reachability state of the UE 100, the AMF 155 may call Namf_EventExposure_Notify towards the SMF 160, and then the AMF 155 may notify the reachability of the UE 100.

[0165] Exemplary PDU session establishment procedures illustrated in FIGS. 12 and 13. In an exemplary embodiment, when a PDU session establishment procedure can be adopted, UE 100 may send a NAS message 1205 (or SM NAS message) to AMF 155, including NSSAI, S-NSSAI (e.g., requested S-NSSAI, permitted S-NSSAI, registered S-NSSAI, etc.), DNN, PDU session ID, request type, previous PDU session ID, N1 SM container (PDU session establishment request), etc. In one example, UE 100 may generate a new PDU session ID to establish a new PDU session. In one example, when an emergency service may be required and there is a possibility that an emergency PDU session has not been established yet, UE 100 may initiate the requested PDU session establishment procedure of UE 100 with a request type indicating an emergency request. In one example, UE 100 may initiate the requested PDU session establishment procedure of UE 100 by sending a NAS message including a PDU session establishment request within the N1 SM container. The PDU session establishment request may include a PDU type, SSC mode, protocol configuration options, etc. In one example, the request type may indicate an initial request if the PDU session establishment is a request to establish a new PDU session, and may indicate an existing PDU session if the request refers to an existing PDU session between 3GPP (registered trademark) access and non-3GPP (registered trademark) access or an existing PDN connection within the EPC. In one example, the request type may indicate an emergency request if the PDU session establishment can be a request to establish a PDU session for an emergency service. The request type may indicate an existing emergency PDU session if the request refers to an existing PDU session for an emergency service between 3GPP (registered trademark) access and non-3GPP (registered trademark) access. In one example, the NAS message sent by UE 100 may be encapsulated by the AN within an N2 message towards AMF 155, which may include user location information and access technology type information. In one example, the PDU session establishment request message may include an SM PDU DN request container including information for PDU session permission by an external DN.In one example, when the procedure can be triggered for an operation in SSC mode 3, the UE 100 may include a previous PDU session ID that can indicate the PDU session ID of the ongoing PDU session to be released within the NAS message. The previous PDU session ID can be an optional parameter that can be included in this case. In one example, the AMF 155 may receive a NAS message (e.g., a NAS SM message) from the AN, together with user location information (e.g., cell ID in the case of RAN 105). In one example, the UE 100 may not trigger the PDU session establishment for the PDU session corresponding to the LADN when the UE 100 is outside the area of availability of the LADN.

[0166] In one example, based on the fact that the request type indicates an initial request and the PDU session ID may not be used for any existing PDU session of the UE 100, the AMF 155 may determine that the NAS message or the SM NAS message can correspond to a request for a new PDU session. If the NAS message does not include the S-NSSAI, the AMF 155 may determine the default S-NSSAI for the requested PDU session according to the subscription of the UE 100 when it can include only one default S-NSSAI, or based on the operator policy. In one example, the AMF 155 may perform the selection 1210 of the SMF 160 and may select the SMF 160. When the request type can indicate an initial request or the request can be due to a handover from EPS, the AMF 155 may store the association of the S-NSSAI, the PDU session ID, and the ID of the SMF 160. In one example, when the request type is an initial request and a previous PDU session ID indicating an existing PDU session can be included in the message, the AMF 155 may select the SMF 160 and may store the association of the new PDU session ID and the ID of the selected SMF 160.

[0167] In one example, AMF 155 may send an N11 message 1215, such as an Nsmf_PDUSession_CreateSMContext request (including SUPI or PEI, DNN, S-NSSAI, PDU session ID, ID of AMF 155, request type, N1 SM container (PDU session establishment request), user location information, access type, PEI, GPSI), or an Nsmf_PDUSession_UpdateSMContext request (SUPI, DNN, S-NSSAI, PDU session ID, ID of AMF 155, request type, N1 SM container (PDU session establishment request), user location information, access type, RAT type, PEI) to SMF 160. In one example, when AMF 155 may not have an association with SMF 160 for the PDU session ID provided by UE 100 (for example, when the request type indicates an initial request), AMF 155 may call an Nsmf_PDUSession_CreateSMContext request, but when AMF 155 already has an association with SMF 160 for the PDU session ID provided by UE 100 (for example, when the request type indicates an existing PDU session), AMF 155 may call an Nsmf_PDUSession_UpdateSMContext request. In one example, the ID of AMF 155 may be the GUAMI of the UE that uniquely identifies the AMF 155 serving UE 100. AMF 155 may transfer the PDU session ID together with the N1 SM container including the PDU session establishment request received from UE 100. When UE 100 registers for emergency services without providing the SUPI, AMF 155 may provide the PEI instead of the SUPI. When UE 100 is registered for emergency services but not authenticated, AMF 155 may indicate that the SUPI is not authenticated.

[0168] In one example, when the request type may not indicate an emergency request or an existing emergency PDU session, and the SMF 160 is not yet registered and the subscription data may not be available, the SMF 160 may register with the UDM 140, obtain the subscription data 1225, and subscribe to be notified when the subscription data may be modified. In one example, when the request type may indicate an existing PDU session or an existing emergency PDU session, the SMF 160 may determine whether the request may be due to a handover between 3GPP® access and non-3GPP® access or due to a handover from EPS. The SMF 160 may identify an existing PDU session based on the PDU session ID. The SMF 160 may not create a new SM context, but instead may update an existing SM context and provide a representation of the updated SM context to the AMF 155 in the response. When the request type may be an initial request and a previous PDU session ID may be included in the Nsmf_PDUSession_CreateSMContext request, the SMF 160 may identify an existing PDU session to be released based on the previous PDU session ID.

[0169] In one example, the SMF 160 may send to the AMF 155 any one of an N11 message response 1220, for example, a PDU session creation / update response, an Nsmf_PDUSession_CreateSMContext response 1220 (cause, SM context ID or N1 SM container (PDU session rejection (cause))), or an Nsmf_PDUSession_UpdateSMContext response.

[0170] In one example, when the SMF 160 may perform secondary authorization / authentication 1230 during PDU session establishment by a DN-AAA server, the SMF 160 may select the UPF 110 and trigger PDU session establishment authentication / authorization.

[0171] In one example, when the request type may indicate an initial request, SMF 160 may select the SSC mode for the PDU session. SMF 160 may select one or more UPFs as needed. In the case of PDU type IPv4 or IPv6, SMF 160 may allocate an IP address / prefix for the PDU session. In the case of PDU type IPv6, SMF 160 may allocate an interface identifier for UE 100 and construct its link-local address for UE 100. For the unstructured PDU type, SMF 160 may allocate IPv6 for the PDU session and N6 point-to-point tunneling (based on UDP / IPv6).

[0172] In one example, when dynamic PCC is deployed, SMF 160 may perform the selection 1235 of PCF 135. When the request type indicates an existing PDU session or an existing emergency PDU session, SMF 160 may use the PCF 135 already selected for the PDU session. When dynamic PCC is not deployed, SMF 160 may apply local policies.

[0173] In one example, SMF 160 may perform the session management policy establishment procedure 1240 to establish a PDU session with PCF 135 and obtain the default PCC rules for the PDU session. The GPSI may be included if available in SMF 160. When the request type of 1215 indicates an existing PDU session, SMF 160 may notify PCF 135 of the events already registered by PCF 135 by the session management policy modification procedure, and PCF 135 may update the policy information in SMF 160. PCF 135 may provide the permitted session AMBR, the permitted 5QI, and ARP to SMF 160. PCF 135 may register the IP allocation / release events (and other events) in SMF 160.

[0174] In one example, PCF 135 may set the ARP of the PCC rule to a value that may be reserved for emergency services based on the emergency DNN.

[0175] In one example, when the request type at 1215 indicates an initial request, the SMF 160 may select an SSC mode for the PDU session. The SMF 160 may select one or more UPFs as needed (1245). For a PDU type of IPv4 or IPv6, the SMF 160 may assign an IP address / prefix to the PDU session. For a PDU type of IPv6, the SMF 160 may assign an interface identifier to the UE 100 for the UE 100 and construct its link-local address. For an unstructured PDU type, the SMF 160 may assign IPv6 to the PDU session and N6 point-to-point tunneling (e.g., based on UDP / IPv6). In one example, for an Ethernet (registered trademark) PDU type PDU session, neither the MAC nor the IP address may be assigned to this PDU session by the SMF 160 for the UE 100.

[0176] In one example, when the request type at 1215 is an existing PDU session, the SMF 160 may maintain the same IP address / prefix that may be assigned to the UE 100 within the source network.

[0177] In one example, when the request type at 1215 indicates an existing PDU session that refers to an existing PDU session that has been moved between 3GPP (registered trademark) access and non-3GPP (registered trademark) access, the SMF 160 may maintain the SSC mode of the PDU session, e.g., the current PDU session anchor and the IP address. In one example, the SMF 160 may trigger, for example, the insertion of a new intermediate UPF 110 or the assignment of a new UPF 110. In one example, when the request type indicates an emergency request, the SMF 160 may select a UPF 110 (1245) and may select SSC mode 1.

[0178] In one example, the SMF 160 may perform the procedure of session management policy modification 1250 and report some events to the previously registered PCF 135. If the request type is an initial request, dynamic PCC is deployed, and the PDU type is IPv4 or IPv6, the SMF 160 may notify the PCF 135 (previously registered) using the IP address / prefix of the assigned UE 100.

[0179] In one example, the PCF 135 may provide the updated policy to the SMF 160. The PCF 135 may provide the permitted session AMBR, permitted 5QI, and ARP to the SMF 160.

[0180] In one example, when the request type indicates an initial request, the SMF 160 may initiate the N4 session establishment procedure 1255 using the selected UPF 110. The SMF 160 may initiate the N4 session modification procedure using the selected UPF 110. In one example, the SMF 160 may send the N4 session establishment / modification request 1255 to the UPF 110 and provide packet detection, enforcement, reporting rules, etc. installed on the UPF 110 for this PDU session. If the CN tunnel information is assigned by the SMF 160, the CN tunnel information may be provided to the UPF 110. If selective user plane deactivation is required for this PDU session, the SMF 160 may determine the inactive timer and provide it to the UPF 110. In one example, the UPF 110 may respond affirmatively by sending the N4 session establishment / modification response 1255. If the CN tunnel information is assigned by the UPF, the CN tunnel information may be provided to the SMF 160. In one example, when multiple UPFs are selected for a PDU session, the SMF 160 may initiate the N4 session establishment / modification procedure 1255 using each UPF 110 of the PDU session.

[0181] In one example, SMF160 may send a message of Namf_Communication_N1N2MessageTransfer1305 (including PDU session ID, access type, N2 SM information (such as PDU session ID, QFI, QoS profile, CN tunnel information, S-NSSAI, session AMBR, PDU session type, etc.), N1 SM container (PDU session establishment acceptance (such as QoS rules, selected SSC mode, S-NSSAI, assigned IPv4 address, interface identifier, session AMBR, selected PDU session type, etc.))) to AMF155. When multiple UPFs are used for a PDU session, the CN tunnel information may include tunnel information related to the UPF110 terminating at N3. In one example, the N2 SM information may carry information that AMF155 may transfer to (R)AN105 (for example, CN tunnel information corresponding to the core network address of the N3 tunnel corresponding to the PDU session, one or more QoS profiles and corresponding QFIs may be provided to (R)AN105, the PDU session ID may be used in AN signaling with UE100 to indicate the association between the AN resource and the PDU session for UE100, etc.). In one example, the PDU session may be associated with an S-NSSAI and a DNN. In one example, the N1 SM container may include a PDU session establishment commitment that AMF155 may provide to UE100. In one example, multiple QoS rules and QoS profiles may be included within the PDU session establishment commitment in N1 SM and N2 SM information. In one example, Namf_Communication_N1N2MessageTransfer 1305 may further include a PDU session ID and information that enables AMF155 to know which access to use towards UE100.

[0182] In one example, AMF155 may send an N2 PDU session request 1310 (including N2 SM information, NAS message (PDU session ID, N1 SM container (such as PDU session establishment commitment, etc.))) to (R)AN105. In one example, AMF155 may send a NAS message 1310 including a PDU session ID targeted to UE100 and a PDU session establishment commitment, and N2 SM information received from SMF160 within the N2 PDU session request 1310, to (R)AN105.

[0183] In one example, (R)AN105 may issue an AN-specific signaling exchange 1315 with UE100 that may be related to the information received from SMF160. In one example, in the case of 3GPP (registered trademark) RAN105, the RRC connection reconfiguration procedure may be performed using UE100 to establish the necessary RAN105 resources related to the QoS rules for the PDU session request 1310. In one example, (R)AN105 may allocate (R)AN105's N3 tunnel information for the PDU session. In the case of dual connectivity, the master RAN105 node may allocate some (zero or more) QFIs set for the master RAN105 node and allocate the others to the secondary RAN105 node. The AN tunnel information may include tunnel endpoints for each participating RAN105 node and QFIs assigned to each tunnel endpoint. The QFI may be assigned to either the master RAN105 node or the secondary RAN105 node. In one example, (R)AN105 may transfer a NAS message 1310 (PDU session ID, N1 SM container (PDU session establishment commitment)) to UE100. (R)AN105 may provide a NAS message to UE100 when the necessary RAN105 resources are established and the allocation of (R)AN105 tunnel information is successful.

[0184] In one example, the N2 PDU session response 1320 may include a PDU session ID, a cause, N2 SM information (a list of PDU session ID, AN tunnel information, grant / deny QFIs), etc. In one example, the AN tunnel information may correspond to the access network address of the N3 tunnel corresponding to the PDU session.

[0185] In one example, the AMF 155 may forward the N2 SM information received from the (R)AN 105 to the SMF 160 via an Nsmf_PDUSession_UpdateSMContext request 1330 (including N2 SM information, request type, etc.). In one example, if the list of denied QFIs is not included in the N2 SM information, the SMF 160 may release the QoS profile related to the denied QFI.

[0186] In one example, the SMF 160 may initiate an N4 session modification procedure 1335 using the UPF 110. The SMF 160 may provide the AN tunnel information to the UPF 110 as well as the corresponding forwarding rules. In one example, the UPF 110 may provide an N4 session modification response 1335 to the SMF 160.

[0187] In one example, the SMF 160 may send an Nsmf_PDUSession_UpdateSMContext response 1340 (cause) to the AMF 155. In one example, after this step, the SMF 160 may register for UE 100 mobility event notifications (e.g., location reports, UE 100 moving into or out of the area of interest) from the AMF 155 by invoking the Namf_EventExposure_Subscribe service operation. For LADN, the SMF 160 may register for event notifications of UE 100 moving into or out of the LADN service area by providing the LADN DNN as an indicator for the area of interest. The AMF 155 may forward the relevant events registered by the SMF 160.

[0188] In one example, SMF 160 may send Nsmf_PDUSession_SMContextStatusNotify (Release) 1345 to AMF 155. In one example, if the PDU session establishment fails during the procedure, SMF 160 may always notify AMF 155 by invoking Nsmf_PDUSession_SMContextStatusNotify (Release) 1345. SMF 160 may release any created N4 session and, if assigned, any PDU session address (e.g., IP address), and may release the association with PCF 135.

[0189] In one example, for the case of PDU type IPv6, SMF 160 may generate an IPv6 Router Advertisement 1350 and send it to UE 100 via N4 and UPF 110.

[0190] In one example, if there is a possibility that the PDU session may not be established, SMF 160 may use Nudm_SDM_Unsubscribe (SUPI, DNN, S-NSSAI) to unsubscribe from the modification of session management subscription data for the corresponding (SUPI, DNN, S-NSSAI) if SMF 160 will no longer process the PDU session of UE 100 for this (DNN, S-NSSAI) (1360). In one example, if there is a possibility that the PDU session may not be established, SMF 160 may use Nudm_UECM_Deregistration (SUPI, DNN, PDU session ID) to deregister for a given PDU session (1360).

[0191] FIG. 14 shows an example of a mobile communication network in which embodiments of the present disclosure may be implemented. The mobile communication network depicted in FIG. 14 includes a wireless device 1410, a base station 1420, a physical core network deployment 1430 of one or more network functions (hereinafter, "CN deployment 1430"), and a physical core network deployment 1440 of one or more network functions (hereinafter, "CN deployment 1440"). Deployments 1430 and 1440 may be elements of the core network.

[0192] Wireless device 1410 can communicate with base station 1420 via air interface 1470. The communication direction from wireless device 1410 to base station 1420 via the air interface is known as the uplink, and the communication direction from base station 1420 to wireless device 1410 via air interface 1470 is known as the downlink. Downlink transmission can be separated from uplink transmission using FDD, TDD, and / or some combination of two duplexing techniques. FIG. 14 shows a single wireless device 1410 and a single base station 1420, but it will be understood that wireless device 1410 may communicate with any number of base stations or other access network components via air interface 1470, and base station 1420 may communicate with any number of wireless devices via air interface 1470.

[0193] Wireless device 1410 may include a processing system 1411 and a memory 1412. Memory 1412 may include one or more computer-readable media, for example, one or more non-transitory computer-readable media. Memory 1412 may include instructions 1413. Processing system 1411 may process and / or execute instructions 1413. Processing and / or execution of instructions 1413 may cause processing system 1411 to perform one or more functions or activities. Memory 1412 may include data (not shown). One of the functions or activities performed by processing system 1411 may be to store data in memory 1412 and / or to retrieve previously stored data from memory 1412. In one example, downlink data received from base station 1420 may be stored in memory 1412, and uplink data for transmission to base station 1420 may be retrieved from memory 1412. Wireless device 1410 may communicate with base station 1420 using a transmission processing system 1414 and a reception processing system 1415. Wireless device 1410 may include one or more antennas 1416 for accessing an air interface 1470. Although not shown in FIG. 14, transmission processing system 1414 and / or reception processing system 1415 may be coupled to dedicated memories similar to but separate from memory 1412 and may include instructions that may be processed and / or executed to perform one or more of their respective functions.

[0194] Wireless device 1410 can include one or more other elements 1419. The one or more other elements 1419 can include software and / or hardware that provides features and / or functions. For example, speakers, microphones, keypads, displays, touch pads, satellite transceivers, Universal Serial Bus (USB) ports, hands-free headsets, Frequency Modulation (FM) radio units, media players, Internet browsers, electronic control units (e.g., for automobiles), and / or one or more sensors (e.g., accelerometers, gyroscopes, temperature sensors, radar sensors, lidar sensors, ultrasonic sensors, optical sensors, cameras, Global Positioning Sensors (GPS), etc.). Wireless device 1410 can receive user input data from one or more other elements 1419 and / or provide user output data to one or more other elements 1419. The one or more other elements 1419 may include a power source. Wireless device 1410 can receive power from the power source and be configured to distribute that power to other components within wireless device 1410. The power source may include one or more power sources, such as batteries, solar cells, fuel cells, or any combination thereof.

[0195] Wireless device 1410 can transmit data to base station 1420 via air interface 1470. To perform the transmission, processing system 1411 can implement layer 3 and layer 2 Open System Interconnection (OSI) functions to process data for uplink transmission. Layer 3 can include a Radio Resource Control layer (RRC). Layer 14 can include a Service Data Application Protocol layer (SDAP), a Packet Data Convergence Protocol layer (PDCP), a Radio Link Control layer (RLC), and a Media Access Control layer (MAC). The data can be provided to a transmission processing system 1414 that can implement layer 1 OSI functions. Layer 1 can include a Physical layer (PHY). Wireless device 1410 can use one or more antennas 1416 to transmit data via air interface 1470. In a scenario where one or more antennas 1416 include multiple antennas, multiple antennas can be used to perform one or more multi-antenna techniques such as spatial multiplexing (e.g., single-user multiple-input multiple-output (MIMO) or multi-user MIMO), transmit / receive diversity, and / or beamforming.

[0196] The wireless device 1410 can receive downlink data from the base station 1420 via the air interface 1470. The downlink data can be received via one or more antennas 1416. The receiving processing system 1415 may implement layer 1 OSI functions on the received downlink data and provide the data to the processing system 1411. The processing system 1411 can implement layer 2 and layer 3 OSI functions to process the received downlink data. The base station 1420 may include elements similar to those of the wireless device 1410. The base station 1420 may include a processing system 1421 and a memory 1422. The memory 1422 may include one or more computer-readable media, for example, one or more non-transitory computer-readable media. The memory 1422 may include instructions 1423. The processing system 1421 can process and / or execute the instructions 1423. The processing and / or execution of the instructions 1423 may cause the processing system 1421 to perform one or more functions or activities. The memory 1422 may include data (not shown). One of the functions or activities performed by the processing system 1421 may be to store data in the memory 1422 and / or retrieve previously stored data from the memory 1422. The base station 1420 can communicate with the wireless device 1410 using a transmission processing system 1424 and a receiving processing system 1425. The base station 1420 may include one or more antennas 1426 for accessing the air interface 1470. The processing system 1421 can implement layer 1 and layer 3 OSI functions. The transmission processing system 1424 and the receiving processing system 1425 can each implement layer 1 OSI functions to perform the transmission of downlink data and the reception of uplink data, respectively.

[0197] Base station 1420 may include an interface system 1427. The interface system 1427 may communicate with one or more elements of the core network via an interface 1480. The interface 1480 may be wired and / or wireless, and the interface system 1427 may include one or more components suitable for communicating via the interface 1480. In FIG. 14, the interface 1480 connects the base station 1420 to a single CN deployment 1430, but the wireless device 1410 may communicate with any number of CN deployments on the interface 1480, and it will be understood that the CN deployment 1430 may communicate with any number of base stations on the interface 1480. The base station 1420 may include one or more other elements 1429 similar to one or more of the one or more other elements 1419.

[0198] The CN deployment 1430 may include one or more network functions (NFs). For example, the CN deployment 1430 may include an AMF and / or a UPF similar to the AMF and UPF shown in FIG. 1. As described above, the CN deployment 1430 may include elements similar to those of the wireless device 1410 and the base station 1420. The CN deployment 1430 may include a processing system 1431 and a memory 1432. The memory 1432 may include one or more computer-readable media, for example, one or more non-transitory computer-readable media. The memory 1432 may include instructions 1433. The processing system 1431 may process and / or execute the instructions 1433. The processing and / or execution of the instructions 1433 may cause the processing system 1431 to perform one or more functions or activities. The memory 1432 may include data (not shown). One of the functions or activities performed by the processing system 1431 may be to store data in the memory 1432 and / or retrieve previously stored data from the memory 1432. The CN deployment 1430 may access the interface 1480 using the interface system 1437. The CN deployment 1430 may also use the interface system 1437 to access the interface 1490. The CN deployment 1430 may communicate with one or more data networks (similar to the DN depicted in FIG. 1 and / or one or more other CN deployments including the CN deployment 1440 depicted in FIG. 14) using the interface 1490. The CN deployment 1430 may include one or more other elements 1439.

[0199] As described above, CN deployment 1440 may include elements similar to those of CN deployment 1430. CN deployment 1440 may include a processing system 1441 and a memory 1442. Memory 1442 may include one or more computer-readable media, for example, one or more non-transitory computer-readable media. Memory 1442 may contain instructions 1443. Processing system 1441 may process and / or execute instructions 1443. The processing and / or execution of instructions 1443 may cause processing system 1441 to perform one or more functions or activities. Memory 1442 may contain data (not shown). One of the functions or activities performed by processing system 1441 may be to store data in and / or retrieve previously stored data from memory 1442. CN deployment 1440 may access interface 1490 using interface system 1447. CN deployment 1440 may include one or more other elements.

[0200] Processing system 1411, processing system 1421, processing system 1431, and / or processing system 1441 can include one or more controllers and / or one or more processors. The one or more controllers and / or the one or more processors can include, for example, general-purpose processors, digital signal processors (DSPs), microcontrollers, application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs) and / or other programmable logic devices, discrete gates and / or transistor logic, discrete hardware components, on-board units, or any combination thereof. Processing system 1411, processing system 1421, processing system 1431, and / or processing system 1441 can perform signal encoding / processing, data processing, power control, input / output processing, and / or any function that enables wireless device 1410, base station 1420, CN deployment 1430, and / or CN deployment 1440 to operate in a mobile communication system.

[0201] Each CN deployment may include one or more network functions. Depending on the context in which the term is used, a network function (NF) may refer to a particular set of functions and / or one or more physical elements (e.g., a processing system and memory including instructions that cause the processing system to perform functions when executed by the processing system) configured to perform those functions. There are many different types of NFs and each type of NF may be associated with a different set of functions. Different NFs may be flexibly deployed at different locations (e.g., different physical core network deployments) or at the same location (e.g., co-located in the same physical core network deployment). Further, the physical CN deployment is not limited to the implementation of NFs. For example, a particular physical CN deployment may further include a base station or a part thereof, and / or a data network or a part thereof. Thus, one or more NFs implemented in a particular physical core network deployment may coexist with one or more non-core elements including elements of the access network or the data network.

[0202] In one example, FIG. 15 is a diagram of a 5G policy and charging control system architecture. The reference architecture of the policy and charging control framework of the 5G system may include one or more of the network functions of a policy control function (PCF), a session management function (SMF), a user plane function (UPF), an access and mobility management function (AMF), a network exposure function (NEF), a network data analytics function (NWDAF), a charging function (CHF), an application function (AF), and a unified data repository (UDR).

[0203] In an embodiment, CHF may support at least one charging method, offline charging, online charging, or centralized charging. In an embodiment, offline charging may be a process in which charging information for network resource usage can be collected simultaneously with that resource usage. At the end of the process, a CDR file may be generated by the network, which can be transferred to the billing domain (BD) of the network operator for the purpose of subscriber billing and / or inter-operator accounting (or additional functions at the discretion of the operator, such as statistics). The BD typically includes a post-processing system such as the operator's charging system or charging mediation device. In an exemplary conclusion, offline charging may be a mechanism in which charging information is provided in real time without affecting the services provided. In an embodiment, offline charging may be a process in which charging information for network resource usage can be collected simultaneously with that resource usage in the same manner as offline charging. However, permission for network resource usage can be obtained by the network before the actual resource usage occurs. In an embodiment, the charging information used in online charging may not necessarily be the same as the charging information used in offline charging. In an exemplary conclusion, online charging may be a mechanism in which charging information can affect the services provided in real time, and therefore, a direct interaction of the charging mechanism with the control of network resource usage may be required. In an embodiment, centralized charging may be a process in which online and offline charging can be combined.

[0204] FIG. 16 is an exemplary call flow for PDU session establishment charging according to an aspect of an embodiment of the present disclosure. In one example, a UE may initiate a PDU session establishment procedure. The PDU session establishment request is composed of one or more of the following: PDU session ID, PDU type, SSC mode, user location information, and access technology type information. In response to the message received from the UE, the AMF may select an SMF and send a message to the selected SMF (e.g., Namf_PDUSession_CreateSMContext request). The SMF may send a response message (e.g., Namf_PDUSession_CreateSMContext response) to the AMF.

[0205] In one example, the SMF may select a PCF and send a message (e.g., SM Policy Association Establishment Request) requesting PCC rules to the PCF, and the PCF may provide PCC rules in a response message (e.g., SM Policy Association Establishment Response). In an example, the SMF may create a charging ID for the PDU session and send a Charging Data Request [Initial] message to the CHF to request permission for the subscriber to start a PDU session triggered by the start of a PDU session charging event. In one embodiment, the CHF may open a CDR for this PDU session and confirm by sending a Charging Data Response [Initial] to the SMF. In an example, the SMF may select a UPF and initiate an N4 session establishment / modification procedure using the selected UPF. The SMF can interact with the AMF. For example, the SMF can send a Namf_Communication_N1N2MessageTransfer message including one or more of the following to the AMF: PDU session ID from the permitted NSSAI, QoS profile, CN tunnel information, and S-NSSAI. In one example, the AMF may interact with the (R)AN and the UE by sending an N2 PDU session request message including the information received from the SMF to the (R)AN, indicating that the PDU session establishment has been accepted.

[0206] In one example, the (R)AN can send an N2 PDU session response message containing one or more of the following to the AMF: PDU session ID, N2 SM information (PDU session ID, AN tunnel information, list of granted / denied QFIs). Here, the AN tunnel information may correspond to the access network address of the N3 tunnel corresponding to the PDU session. In one example, the AMF can send an Nsmf_PDUSession_UpdateSMContext request message containing the N2SM information received from the (R)AN to the SMF. In an embodiment, the SMF can initiate an N4 session modification procedure using the UPF. The SMF can provide the AN tunnel information to the UPF as well as the corresponding forwarding rules. The UPF can send a response message to the SMF. In an embodiment, the SMF can request an allocation from the CHF, for example, when a "service data flow start" event may require an allocation from the CHF. The SMF can send a message to the CHF (e.g., charging data request [update]). In an embodiment, for online charging or centralized charging, the SMF can request an allocation from the CHF when the allocated allocation is consumed or when the trigger is satisfied to request an allocation.

[0207] In an embodiment, the UPF can report the resource usage of the PDU session to the SMF. In an embodiment, the UPF can report the resource usage of the wireless device to the SMF by implementing a charging control rule, and the SMF can send a message (e.g., charging data request [update]) containing the resource usage information received from the UPF to the CHF. In an embodiment, the CHF can update the CDR for this PDU session. The CHF can approve the SMF by sending a charging data response message. In an embodiment, the SMF can send an Nsmf_PDUSession_UpdateSMContext response message to the AMF.

[0208] FIG. 17 is an exemplary call flow according to an aspect of an embodiment of the present disclosure. In one example, the purpose of the overload start procedure may be to notify a base station (e.g., an NG-RAN node) and reduce the signaling load on the associated AMF. The procedure can use non-UE-related signaling. The NG-RAN node may receive an overload start message and may assume the AMF that receives the message as being in an overload state. The overload start message may include an AMF overload response IE. If the AMF overload response IE includes an overload action IE, the NG-RAN node may use the overload action IE to identify the associated signaling traffic.

[0209] In one example, if the overload action IE is set to reject the establishment of an RRC connection for data transfer of non-emergency mobile origin (e.g., reject traffic corresponding to RRC causes “mo-data”, “mo-SMS”, “mo-VideoCall”, and “mo-VoiceCall”), the NG-RAN node may reduce the signaling traffic by the indicated percentage if the AMF traffic load reduction indication IE is included in the overload start message, or otherwise, the NG-RAN node may ensure that only the signaling traffic not indicated as rejected is sent to the AMF.

[0210] In one example, when the overload action IE is set to “reject the establishment of an RRC connection for signaling” (e.g., reject traffic corresponding to RRC causes “mo-data”, “mo-SMS”, “mo-signaling”, “mo-VideoCall”, and “mo-VoiceCall”), the NG-RAN node may reduce the signaling traffic by the indicated percentage if the AMF traffic load reduction indication IE is included in the overload start message, or otherwise, the NG-RAN node may ensure that only the signaling traffic not indicated as rejected is sent to the AMF.

[0211] In one embodiment, when the overload action IE is set to "permit only RRC connection establishment for emergency sessions and mobile termination services" (for example, permit only traffic corresponding to RRC causes "urgency" and "mt-Access"), if the AMF traffic load reduction indication IE is included in the overload start message, the NG-RAN node may reduce the signaling traffic by the indicated percentage; otherwise, the NG-RAN node may ensure that only the signaling traffic not indicated as rejected is sent to the AMF.

[0212] In one embodiment, when the overload action IE is set to "permit only RRC connection establishment for high-priority sessions and mobile termination services" (for example, permit only traffic corresponding to RRC causes "highPriorityAccess", "mps-PriorityAccess", "mcs-PriorityAccess", and "mt-Access"), if the AMF traffic load reduction indication IE is included in the overload start message, the NG-RAN node may reduce the signaling traffic by the indicated percentage; otherwise, the NG-RAN node may ensure that only the signaling traffic not indicated as rejected is sent to the AMF.

[0213] In one embodiment, when the overload start NSSAI list IE is included in the overload start message, the NG-RAN node may reduce the signaling traffic for the UE by only the percentage indicated for the UE where the requested NSSAI contains only S-NSSAIs included in the overload start NSSAI list IE, and the signaling traffic is shown to be reduced by the overload action IE within the slice overload response IE if the slice traffic load reduction indication IE is present, and otherwise, the NG-RAN node ensures that only the signaling traffic from the UE whose requested NSSAI contains S-NSSAIs other than those included in the overload start NSSAI list IE, or the signaling traffic that is not shown to be reduced by the overload action IE in the slice overload response IE for the UE when the requested NSSAI matches, is sent to the AMF. When overload control is in progress and the NG-RAN node receives another overload start message, the NG-RAN node may replace the content of the previously received information with the new one.

[0214] In the existing technology, the UE may send an RRC message to access the network and / or establish a connection with a base station in the network. The message may include a request for a specific network slice. One or more base stations may receive the message and set up an RRC connection of the UE with the base station via the requested network slice. One or more base stations may send an RRC message to the UE to complete the RRC connection. When the connection of the RRC connection is successful, the UE may communicate with the core network via the base station, for example, using NAS messages.

[0215] A network slice can access a large number of UEs via various (R)ANs while the UE has potentially established multiple PDU sessions. In one example, the network may be configured to guarantee / maintain a certain level of QoS for the users of the network slice, for example, to guarantee / maintain that the UEs connected to the network slice have a latency below a specific threshold. When a large number of UEs establish a large number of PDU sessions for the same network slice, the network capacity to achieve the guaranteed level of QoS is impaired. Under certain conditions, the core network control plane (e.g., AMF, SMF) can prevent the overload of the network slice by rejecting UE connection and / or PDU session establishment requests. For example, when the UE receives a notification that the NAS setup request has been rejected, the UE setup is delayed and the user experience is impaired. Existing technologies may not efficiently support the control of the number of UEs and / or PDU sessions per network slice. Since the requests for new connections are not satisfied, the UE is likely to attempt another connection, increasing the signaling overhead and power consumption in the network. To avoid waste and improve the user experience, an improved method is needed to address the inefficiencies associated with the overload of the network slice.

[0216] Exemplary embodiments of the present disclosure implement an enhanced mechanism to support the control of the number of UEs and / or the number of PDU sessions per network slice. In an exemplary embodiment of the present disclosure, a network function (e.g., a core network function, e.g., an AMF, an SMF) may provide an overload notification of a network slice to a base station. Exemplary embodiments of the present disclosure may implement an enhanced mechanism for providing an allocation reach notification for a network slice to a base station. A UE may transmit an RRC message for an RRC connection to a first network slice to a base station. In one embodiment, the base station may transmit an RRC message including a cause value of an overload notification per network slice to the UE when, for example, the network allocation of the network slice is reached. The RRC message may include information on a second network slice. The RRC message may be, for example, an RRC release message that releases an RCC connection. Exemplary embodiments of the present disclosure may provide an enhanced mechanism for providing a release cause of an allocation reach notification per network slice to a UE. As a result, access by the UE to an overloaded network slice is reduced. Next, the UE may access a non-overloaded network slice, which may result in a better user experience, a reduction in signaling overhead, and a reduction in power consumption. In an exemplary embodiment, the base station may transmit an RRC message including a cause value before the UE transmits a message to a core network function. Thereby, since access to the network is rejected before the UE starts NAS signaling with the core network, the delay of the UE connection to the network can be reduced. Exemplary embodiments may increase RRC signaling overhead and BS processing requirements, but shorten the time until connection to an overloaded network slice is rejected. In one example, the UE may reconnect to a second network slice that is not in an overloaded state. Examples of embodiments may improve the user experience and reduce the overall connection setup and PDU establishment delay.

[0217] FIG. 18 shows an exemplary call flow that may include one or more actions. In one example, (R)AN may send a message (e.g., Nnwdaf_AnalyticsSubscription_Subscribe) to a network function (e.g., NWDAF, OAM) to subscribe to an event / notification when an assignment reaches the number of UEs per network slice (e.g., per first S-NSSAI) and / or the number of PDU sessions per network slice. In one embodiment, the first S-NSSAI may be the first requested S-NSSAI. In one embodiment, the first S-NSSAI may be the first permitted S-NSSAI. In one embodiment, the first NSSAI may include the first S-NSSAI. In one embodiment, the first NSSAI may be the first requested NSSAI. In one embodiment, the first NSSAI may be the first permitted NSSAI. The Nnwdaf_AnalyticsSubscription_Subscribe message may include a parameter indicating the first S-NSSAI. In one embodiment, the Nnwdaf_AnalyticsSubscription_Subscribe message may include a parameter indicating the first NSSAI, and the first NSSAI may include the first S-NSSAI. For example, (R)AN may send the Nnwdaf_AnalyticsSubscription_Subscribe message to NWDAF to subscribe to an event / notification when an assignment reaches the maximum number of UEs for the first S-NSSAI and / or the maximum number of PDU sessions for the first S-NSSAI. A network function (e.g., NWDAF, OAM) may receive a report message from one or more (R)ANs and / or one or more AMFs, and the report message may include the number of UEs and / or the number of PDU sessions in one or more (R)ANs and / or one or more AMFs. The network function may calculate the total number of UEs per network slice and / or the total number of PDU sessions per network slice for the PLMN.For example, the network function may receive a first number of UEs for a first S-NSSAI for a first PLMN from (R)AN1, may receive a second number of UEs for the first S-NSSAI for the first PLMN from (R)AN2, and may add the first number of UEs and the second number of UEs together as the total number of UEs for the first S-NSSAI for the first PLMN.

[0218] In one embodiment, a base station (e.g., (R)AN1) may receive, from an AMF (e.g., AMF1), a first message indicating that a first S-NSSAI is overloaded. In one embodiment, a base station (e.g., (R)AN1) may receive, from a network function (e.g., NWDAF, OAM), a first message indicating that a first S-NSSAI is overloaded. In one embodiment, a base station (e.g., (R)AN1) may receive, from a network function via an AMF (e.g., AMF1), a first message indicating that a first S-NSSAI is overloaded. In one example, the overload may be due to reaching the allocation for the number of UEs for a network slice. In one example, the overload may be due to reaching the allocation for the number of PDU sessions for a network slice. For example, when the allocation is reached for the number of UEs per network slice and / or when the allocation is reached for the number of PDU sessions per network slice, the network function may send a notification message to one or more (R)ANs and / or one or more AMFs. For example, when the allocation is reached for the maximum number of UEs for a first S-NSSAI for a first PLMN and / or when the allocation is reached for the maximum number of PDU sessions for a first S-NSSAI for a first PLMN, (R)AN1 receives an Nnwdaf_AnalyticsSubscription_Notify message from AMF1 / NWDAF, and the Nnwdaf_AnalyticsSubscription_Notify message may indicate that the allocation has been reached for the maximum number of UEs for a first S-NSSAI for a first PLMN and / or that the allocation has been reached for the maximum number of PDU sessions for a first S-NSSAI for a first PLMN. In one embodiment, the first message may be an overload start message. In one embodiment, the first message may be an overload indication message. In one embodiment, the first message may be an allocation reached indication message.For example, (R)AN1 may receive an overload start message from NWDAF indicating that the first S-NSSAI of the first PLMN is overloaded because the allocation has reached the number of UEs for the first S-NSSAI. For example, (R)AN1 may receive an overload indication message from OAM indicating that the first S-NSSAI of the first PLMN is overloaded because the allocation has reached the number of PDU sessions for the first S-NSSAI.

[0219] In one embodiment, a base station (e.g., (R)AN1) may receive a first message from a network function (e.g., NWDAF, OAM) indicating that the allocation has reached the number of UEs for the first S-NSSAI. In one embodiment, a base station (e.g., (R)AN1) may receive a first message from the AMF indicating that the allocation has reached the number of UEs for the first S-NSSAI. In one embodiment, a base station (e.g., (R)AN1) may receive a first message from a network function (e.g., NWDAF, OAM) indicating that the allocation has reached the number of PDU sessions for the first S-NSSAI. In one embodiment, a base station (e.g., (R)AN1) may receive a first message from the AMF indicating that the allocation has reached the number of PDU sessions for the first S-NSSAI.

[0220] The first message may include a first information element (IE) indicating a network slice (e.g., a first S-NSSAI). The first message may include a second IE indicating that an allocation has reached the number of UEs for a network slice (e.g., a first S-NSSAI) per PLMN (e.g., for a first PLMN). The first message may include a third IE indicating that an allocation has reached the number of PDU sessions for a network slice (e.g., a first S-NSSAI) per PLMN (e.g., for a first PLMN). The first message may include a fourth IE indicating an action of the (R)AN for RRC connection of a network slice (e.g., a first S-NSSAI) for a PLMN (e.g., a first PLMN). The action of the (R)AN may be to release the RRC connection of a network slice (e.g., a first S-NSSAI) for a PLMN (e.g., a first PLMN).

[0221] In one example, a network function (e.g., NWDAF, OAM) may send a second message (e.g., Nnwdaf_AnalyticsSubscription_Notify) to the AMF2 / (R)AN2 indicating that an allocation has reached the maximum number of UEs for a first S-NSSAI for a first PLMN and / or that an allocation has reached the maximum number of PDU sessions for a first S-NSSAI for a first PLMN.

[0222] When the upper layer requests the establishment of an RRC connection, the UE can initiate the RRC setup procedure, which may already have obtained the essential system information from the base station (e.g., (R)AN1). The UE may request the setup of an RRC connection by sending an RRCSetupRequest message to (R)AN1. The RRCSetupRequest message may include UE identification information (e.g., 5G-S-TMSI). In response to the message received from the UE, (R)AN1 may send an RRCSetup message for the RRC connection to the UE. The RRCSetup message may include an RRC-TransactionIdentifier and / or a RadioBearerConfig information element (IE). The RadioBearerConfig IE may be used to add, modify, and / or release signaling and / or data radio bearers between the UE and (R)AN1. In response to the RRCSetup message received from (R)AN1, the UE may send an RRCSetupComplete message for the RRC connection to (R)AN1. The RRCSetupComplete message may include an RRC-TransactionIdentifier, 5G-S-TMSI, an s-NSSAI-List IE, a selectedPLMN-Identity IE, and / or a dedicatedNAS-Message. The s-NSSAI-List IE may include one or more S-NSSAIs (e.g., the first (requested) S-NSSAI). In one embodiment, the selectedPLMN-Identity IE may include the identifier of the first PLMN.

[0223] In response to the RRCSetupComplete message received from the UE, based on the RRCSetupComplete message received from the UE and / or the first message received from the AMF, the base station (e.g., (R)AN1) may determine an action for the RRC connection of the radio device. The action may be to release the RRC connection for the radio device. For example, based on the first S-NSSAI in the RRCSetupComplete message, and / or the first S-NSSAI in the first message, and / or the second IE of the first message indicating that the allocation has reached the maximum number of UEs for the first S-NSSAI for the first PLMN, and / or the fourth IE of the first message indicating the action of (R)AN1 for the RRC connection of the network slice, (R)AN1 may determine to release the RRC connection for the first S-NSSAI for the first PLMN for the UE. For example, based on the first S-NSSAI in the RRCSetupComplete message, and / or the first S-NSSAI in the first message, and / or the third IE of the first message indicating that the allocation has reached the maximum number of PDU sessions for the first S-NSSAI for the first PLMN, and / or the fourth IE of the first message indicating the action of (R)AN1 for the RRC connection of the network slice, (R)AN1 may determine to release the RRC connection for the first S-NSSAI for the first PLMN for the UE.

[0224] Based on the RRCSetupComplete message received from the UE and / or the first message received from the AMF, the base station (e.g., (R)AN1) may determine the S-NSSAI that was rejected for the RRC connection of the radio device. For example, the base station (e.g., (R)AN1) may determine the NSSAI that was rejected for the RRC connection for the radio device, and the rejected NSSAI may include the rejected S-NSSAI. For example, based on the first S-NSSAI in the RRCSetupComplete message, and / or the first S-NSSAI in the first message, and / or the second IE of the first message indicating that the allocation has reached the maximum number of UEs for the first S-NSSAI for the first PLMN, (R)AN1 may determine the rejected S-NSSAI (e.g., the first S-NSSAI). The rejected S-NSSAI may be used to indicate to the UE that the RRC connection related to the rejected S-NSSAI has been rejected and may be released.

[0225] Based on the RRCSetupComplete message received from the UE and / or the first message received from the AMF and / or the performance statistical information, the base station (e.g., (R)AN1) may determine the waiting time for the rejected S-NSSAI. The performance statistical information may include the average connection time per UE per network slice. The performance statistical information may include the average connection time per PDU session per network slice. The performance statistical information may include the average connection time per PDU session per UE per network slice per PLMN. In one embodiment, (R)AN1 may determine the performance statistical information based on local statistical information. In one embodiment, (R)AN1 may receive the performance statistical information from a network function (e.g., NWDAF, OAM). The waiting time may include a value (e.g., minutes, seconds) indicating that the UE may attempt to set up a new RRC connection for the rejected S-NSSAI after the value of time.

[0226] In response to the decision, the base station (e.g., (R)AN1) may send an RRC release message to the UE indicating that the first S-NSSAI is overloaded. In one embodiment, the RRC release message may include a release cause indicating that the first S-NSSAI is overloaded. In one embodiment, the RRC release message may include a release cause indicating that the first S-NSSAI is overloaded because the allocation for the first S-NSSAI has reached the number of UEs for the first S-NSSAI. In one embodiment, the RRC release message may include a release cause indicating that the first S-NSSAI is overloaded because the allocation for the first S-NSSAI has reached the number of PDU sessions for the first S-NSSAI. In one embodiment, the RRC release message may include the rejected S-NSSAI. In one embodiment, the RRC release message may include a latency.

[0227] Figure 19 shows an example of an RRC Release message. The RRC Release message may include a releaseCause IE, an overloadedS-NSSAI IE, a rejectedS-NSSAI IE, and / or a waitTime IE. The releaseCause IE may indicate the reason for releasing the RRC connection. The overloadedS-NSSAI IE may indicate the network slice in an overload state associated with the releaseCause IE. The releaseCause IE may include at least one of the following values: NetworkSliceOverloaded, QuotaNumberUEsReached, and / or QuotaNumberPDUSessionsReached. NetworkSliceOverloaded may indicate that the RRC connection was released because the network slice (e.g., OverloadedS-NSSAI) was overloaded. QuotaNumberUEsReached may indicate that the RRC connection was released because the number of UEs assigned to the network slice (e.g., OverloadedS-NSSAI) was reached. QuotaNumberPDUSessionsReached may indicate that the RRC connection was released because the number of PDU sessions assigned to the network slice (e.g., OverloadedS-NSSAI) was reached. The rejectedS-NSSAI IE may indicate the network slice rejected by the base station. The waitTime IE may include a value indicating that the UE may attempt to set up a new RRC connection for the S-NSSAI rejected after a value of time.

[0228] Figure 20 shows an RRCRelease message of another example. The RRCRelease message may include a releaseCause IE, an overloadedS-NSSAI IE, a rejectedS-NSSAI IE, and / or a waitTime IE. The releaseCause IE may indicate the reason for releasing the RRC connection. The overloadedS-NSSAI IE may indicate the network slice in an overload state associated with the releaseCause IE. The releaseCause IE may include at least one of the following values: NetworkSliceOverloadedofQuotaNumberUEsReached, and / or NetworkSliceOverloadedQuotaNumberPDUSessionsReached. NetworkSliceOverloadedofQuotaNumberUEsReached may indicate that the RRC connection was released because the network slice (e.g., OverloadedS-NSSAI) became overloaded due to reaching the assigned number of UEs. NetworkSliceOverloadedQuotaNumberPDUSessionsReached may indicate that the RRC connection was released because the network slice (e.g., OverloadedS-NSSAI) became overloaded due to reaching the assigned number of PDU sessions. The rejectedS-NSSAI IE may indicate the network slice rejected by the base station. The waitTime IE may include a value indicating that the UE may attempt to set up a new RRC connection for the S-NSSAI rejected after a value of time.

[0229] In response to the RRC release message received from the base station, the UE may determine / execute an action based on the RRC release message. In one embodiment, the action may be to establish a second (new) RRC connection with the base station. In one example, the action may be to send a new RRC Setup Complete message to the base station. In one embodiment, the UE may determine a second requested S-NSSAI based on the release cause. The UE may set up a second (new) RRC connection with the (R) AN1. For example, the UE may send a second RRC Setup Request message to the (R) AN1 and may receive a second RRC Setup message for the second (new) RRC connection from the (R) AN1. The UE may send a second RRC Setup Complete message for the second RRC connection to the (R) AN1, and the second RRC Setup Complete message may include the second requested S-NSSAI. In one example, after waiting for a waiting time (for example, a timer having a waiting time value expires), the UE may set up a second (new) RRC connection with the (R) AN1, and the UE may send a second RRC Setup Complete message for the second RRC connection to the (R) AN1. The second RRC Setup Complete message may include the rejected S-NSSAI (for example, the first S-NSSAI).

[0230] FIG. 21 is an exemplary diagram showing the procedure of a base station according to one aspect of an embodiment of the present disclosure.

[0231] FIG. 22 is an exemplary diagram showing the procedure of a wireless device according to one aspect of an embodiment of the present disclosure.

[0232] In the existing technology, a UE may send a message to access the network and / or establish a connection with a base station in the network. The message may include a request for a specific network slice. One or more base stations may receive the message and set up an RRC connection of the UE with the base station via the requested network slice. One or more base stations may complete the RRC connection. When the connection of the RRC connection is successful, the UE can communicate with the core network via the base station, for example, using NAS messages.

[0233] A network slice can access multiple UEs via various (R)ANs while the UE has potentially established multiple PDU sessions. In one example, the network may be configured to guarantee / maintain a certain level of QoS for the users of the network slice. For example, it guarantees / maintains that the UEs connected to the network slice have a delay below a specific threshold. When multiple UEs establish multiple PDU sessions for the same network slice, the network's ability to achieve the guaranteed level of QoS is impaired. Under certain conditions, the core network control plane (e.g., AMF, SMF) can prevent network slice overload by rejecting UE connection and / or PDU session establishment requests. For example, when the UE receives a notification that the NAS setup request has been rejected, the UE setup is delayed and the user experience is impaired. The AMF and / or SMF that receive the PDU session establishment request may determine that the allocation for the number of PDU sessions for the network slice has been reached. The AMF and / or SMF may send a NAS message rejecting the establishment of one or more PDU sessions to the UE. In one example, this process may result in the establishment of PDU sessions exceeding the allocation because the SMF may not update the information regarding the number of PDU sessions established per network slice. In an embodiment, this process may result in early rejection of PDU session establishment before reaching the allocation because the SMF may not update the information regarding the number of PDU sessions established per network slice. In one example, this may be the result of having multiple SMFs and / or AMFs in the radio network, for example. Existing technologies may not efficiently support the control of the number of UEs and / or PDU sessions per network slice. This may result in a degradation of the QoS of the radio devices in the network.

[0234] Exemplary embodiments of the present disclosure may provide an enhanced mechanism for a first network function (e.g., SMF and / or NSSF) to efficiently support control of the number of UEs per network slice and / or the number of PDU sessions, and to establish a PDU session for a UE. In one example, the NSSF may receive an allocation for the number of PDU sessions from a network server (e.g., OAM, NWDAF). A network function (e.g., SMF and / or AMF) may receive the NSSAI (for network slice) requested by the UE. The network function may send a request to the NSSF indicating the establishment of at least one PDU session in the network slice. The NSSF may determine that it has reached the allocation for the PDU sessions within the network slice. The NSSF may send an indication to the network function that it has reached the allocation for the number of PDU sessions for the first network slice. The NSSF may send a second network slice for the PDU session to the network function. Exemplary embodiments may enable the network function to send a NAS rejection message to the wireless device based on the updated number of PDU sessions per network slice in the wireless network and based on more accurate information. The network function may send the second network slice to the wireless device. The wireless device may send a message to the network function to establish at least one PDU session in the second network slice. Exemplary embodiments enhance the QoS of the PDU sessions in the network slice by accurately implementing the allocation of the number of PDU sessions per network slice in the wireless network. An example of an embodiment may enable the maintenance of the connection for the first network slice even when the allocation is reached by using the second network slice.

[0235] In the existing technology, a UE may send messages to access the network and / or establish a connection with a base station in the network. The message may include a request for a specific network slice. One or more base stations may receive the message and set up an RRC connection of the UE with the base station via the requested network slice. One or more base stations may complete the RRC connection. When the connection of the RRC connection is successful, the UE can communicate with the core network via the base station, for example, using NAS messages.

[0236] A network slice can access multiple UEs via various (R)ANs with the UE potentially having established multiple PDU sessions. In one example, the network may be configured to guarantee / maintain a certain level of QoS for the users of the network slice, for example, guarantee / maintain that the UE connected to the network slice has a delay below a specific threshold. When multiple UEs establish multiple PDU sessions for the same network slice, the network's ability to achieve the guaranteed level of QoS is impaired. Under certain conditions, the core network control plane (e.g., AMF, SMF) may prevent overloading of the network slice by rejecting UE connection and / or PDU session establishment requests. For example, when the UE receives a notification that the NAS setup request has been rejected, the UE setup is delayed and the user experience is impaired. The AMF and / or SMF that receive the PDU session establishment request may determine that the allocation has been reached for the number of PDU sessions for the network slice. The AMF and / or SMF may send a NAS message rejecting the establishment of one or more PDU sessions to the UE. In the example, the UE connection to the network slice may be rejected and the UE may not be able to connect to the network. As a result, the QoS of the wireless device may deteriorate. The existing technology may not efficiently support the control of the number of UEs and / or PDU sessions per network slice.

[0237] In exemplary embodiments of the present disclosure, a first network function (e.g., SMF and / or NSSF) may efficiently support control of the number of UEs per network slice and / or the number of PDU sessions, and provide an enhanced mechanism for establishing a PDU session for a UE. A network function (e.g., SMF and / or AMF) may receive a requested NSSAI from a UE. The network function may determine that it has reached a network allocation for the number of PDU sessions for a network slice. The NSF may receive an indication from a network function (e.g., AMF, SMF) that it has reached the allocation for the number of packet data unit (PDU) sessions for a first network slice. The NSSF may determine a second network slice for a wireless device. The NSSF may send the second network slice of the UE to a network function. The network function may send the second network slice to the wireless device. The wireless device may send a message to the network function to establish at least one PDU session in the second network slice. Exemplary embodiments may enable a UE to establish at least one PDU session based on a second network slice. Examples of embodiments may enable maintenance of a connection even when the allocation for a first network slice has been reached by using a second network slice.

[0238] Exemplary embodiments may enable a network function to send a NAS rejection message to a wireless device based on an updated number of PDU sessions per network slice and based on more accurate information. Examples of embodiments enhance the QoS of PDU sessions in a network slice by accurately implementing the allocation of the number of PDU sessions per network slice within a wireless network.

[0239] FIG. 23 shows an exemplary call flow that may include one or more actions. In one example, the SMF may send a message (e.g., Nnwdaf_AnalyticsSubscription_Subscribe) to a network function (e.g., NWDAF, OAM) to subscribe to an event / notification when an allocation reaches the number of PDU sessions per network slice per PLMN (e.g., per first PLMN). In one embodiment, the first S-NSSAI may be the first requested S-NSSAI. In one embodiment, the first S-NSSAI may be the first permitted S-NSSAI. In one embodiment, the first NSSAI may include the first S-NSSAI. In one embodiment, the first NSSAI may be the first requested NSSAI. In one embodiment, the first NSSAI may be the first permitted NSSAI. The Nnwdaf_AnalyticsSubscription_Subscribe message may include a parameter indicating the first S-NSSAI. In one embodiment, the Nnwdaf_AnalyticsSubscription_Subscribe message may include a parameter indicating the first NSSAI, and the first NSSAI may include the first S-NSSAI. For example, the SMF may send the Nnwdaf_AnalyticsSubscription_Subscribe message to the NWDAF to subscribe to an event / notification when an allocation reaches the maximum number of PDU sessions for the first S-NSSAI. The network function (e.g., NWDAF, OAM) may receive a report message from one or more AMFs / SMFs, and the report message may include the number of PDU sessions per network slice within the one or more AMFs / SMFs. The network function may calculate the total number of PDU sessions per network slice for the PLMN.

[0240] The SMF may receive, from a network function, a first message indicating that the allocation has reached the number of PDU sessions for the first S-NSSAI. In one embodiment, the first message may be an overload indication message. In one embodiment, the first message may be an allocation reached indication message. For example, the NWDAF may send an Nnwdaf_AnalyticsSubscription_Notify message to the SMF indicating that the allocation has reached the maximum number of PDU sessions for the first S-NSSAI for the first PLMN. For example, the OAM may send an allocation reached indication message to the SMF indicating that the allocation has reached the maximum number of PDU sessions for the first S-NSSAI for the first PLMN. The first message may include a first information element (IE) indicating a network slice (e.g., the first S-NSSAI). The first message may also include a second IE indicating that the allocation has reached the number of PDU sessions per network slice (e.g., the first S-NSSAI) per PLMN (e.g., the first PLMN). The first message may also include a third IE indicating the action of the SMF with respect to the PDU session of the network slice (e.g., the first S-NSSAI) for the PLMN (e.g., the first PLMN). The action of the SMF may be to reject the establishment of the PDU session of the network slice (e.g., the first S-NSSAI) for the PLMN (e.g., the first PLMN). The action of the SMF may be to determine the allowed S-NSSAI for the PDU session for the network slice (e.g., the first S-NSSAI) for the PLMN (e.g., the first PLMN).

[0241] In one example, the UE may send a NAS message including at least one of the following to the AMF: S-NSSAI (e.g., the first S-NSSAI), DNN, PDU session ID, request type, or N1 SM container (PDU session establishment request). The UE may start the PDU session establishment procedure requested by the UE by sending a NAS message including a PDU session establishment request message within the N1 SM container.

[0242] The PDU session establishment request message may include at least one of a PDU session ID, a requested PDU session type, or a requested SSC mode. In response to the message received from the UE, the AMF may select an SMF and send a message (e.g., a PDU session establishment request, PDUSession_CreateSMContext request) including at least one of the following to the SMF: SUPI, DNN, S-NSSAI (e.g., the first S-NSSAI), and / or a network slice instance identifier, PDU session ID, AMF ID, request type, PCF identifier, priority access, N1 SM container (PDU session establishment request), user location information, access type, PEI). By way of example, the PCF identifier may be an identifier, or an IP address, or an FQDN identifying the PCF.

[0243] In response to a message received from the AMF, the SMF may take one or more actions. In an exemplary action, the SMF may determine a second permitted S-NSSAI based on a first message received from a network function and a PDU session establishment request message received from the AMF / UE. In one embodiment, the SMF may determine a second permitted NSSAI, where the second permitted NSSAI includes the second permitted S-NSSAI. In an exemplary action, the SMF may determine a second permitted S-NSSAI based on the first message and the first S-NSSAI. For example, based on the first S-NSSAI of the PDU session establishment request message, and / or the first S-NSSAI of the first message, and / or a second IE of the first message indicating that the allocation has reached the maximum number of PDU sessions for the first S-NSSAI for the first PLMN, and / or a third IE of the first message indicating the action of the SMF for the PDU session of the first S-NSSAI, the SMF may determine to reject the PDU session establishment request for the first S-NSSAI for the first PLMN. For example, based on the first S-NSSAI of the PDU session establishment request message (e.g., having a network slice type for URLLC), and / or the first S-NSSAI of the first message, and / or a second IE of the first message indicating that the allocation has reached the maximum number of PDU sessions for the first S-NSSAI for the first PLMN, and / or a third IE of the first message indicating the action of the SMF for the PDU session of the first S-NSSAI, the SMF may determine a second permitted S-NSSAI (e.g., having a network slice type for MIoT) for the PDU session for the first PLMN.

[0244] In an exemplary action, the SMF may send a message (e.g., Nnssf_NSSelection_Get) requesting a network slice of a PLMN (e.g., the first PLMN) to the NSSF. The Nnssf_NSSelection_Get message may include network slice information received from the AMF / UE (e.g., the first S-NSSAI), and / or a parameter indicating that an allocation has been reached for the number of PDU sessions for the first S-NSSAI with respect to the first PLMN (e.g., the maximum number of PDU sessions). The Nnssf_NSSelection_Get message may include UE identification information (e.g., SUPI), DNN, and / or PDU session ID. In response to the Nnssf_NSSelection_Get message received from the SMF, the NSSF may determine a second permitted S-NSSAI based on the first message and the first S-NSSAI. In one embodiment, the NSSF may determine a second permitted NSSAI, and the second permitted NSSAI includes the second permitted S-NSSAI. For example, based on the first S-NSSAI and / or a parameter indicating that an allocation has been reached for the maximum number of PDU sessions for the first S-NSSAI with respect to the first PLMN, the NSSF may determine a second permitted S-NSSAI for the PDU session with respect to the first PLMN. The NSSF may send a response message (e.g., Nnssf_NSSelection_Get Response) including the second permitted S-NSSAI, UE identification information, DNN, and / or PDU session ID to the SMF. In one embodiment, the NSSF may send a response message (e.g., Nnssf_NSSelection_Get Response) including the second permitted NSSAI, UE identification information, DNN, and / or PDU session ID to the SMF.

[0245] In an exemplary action, in response to the decision, the SMF may send a PDU session response message to the UE via the AMF. In an example of the action, in response to the Nnssf_NSSelection_Get Response message received from the NSSF, the SMF may send a PDU session response message to the UE via the AMF. In an embodiment, the PDU session response message may be a PDU session commitment message. The PDU session commitment message may include a second permitted S-NSSAI indicating that the second permitted S-NSSAI may be used for the PDU session for the first PLMN. In one embodiment, the PDU session commitment message may include a second permitted NSSAI, and the second permitted NSSAI includes the second permitted S-NSSAI. In an embodiment, the PDU session response message may be a PDU session rejection message. The PDU session rejection message may include a cause value indicating that the PDU session was rejected because the allocation reached the maximum number of PDU sessions for the first S-NSSAI for the first PLMN. In one embodiment, the PDU session rejection message may include a second permitted NSSAI, and the second permitted NSSAI includes the second permitted S-NSSAI. The PDU session rejection message may include a retry indicator indicating that the second permitted S-NSSAI and / or the UE may retry to establish a second (new) PDU session for the second permitted S-NSSAI with respect to the first PLMN.

[0246] In response to a message received from the AMF / SMF, the SMF may take one or more actions. In an exemplary action, the UE may use a second permitted S-NSSAI for the PDU session based on the PDU session commitment message and / or the second permitted S-NSSAI. For example, the UE may use a second permitted S-NSSAI (e.g., of the eMBB type) for an application service (e.g., video) on the PDU session. In an exemplary action, the UE may determine a second requested S-NSSAI based on the PDU session rejection message and / or the second permitted S-NSSAI. For example, the UE may determine the second requested S-NSSAI based on the second permitted S-NSSAI and / or the retry indicator. The UE may send a second PDU session establishment request message including the second requested S-NSSAI to the AMF / SMF.

[0247] FIG. 24 shows an exemplary call flow that may include one or more actions. In one example, the NSSF may send a message (e.g., Nnwdaf_AnalyticsSubscription_Subscribe) to a network function (e.g., NWDAF, OAM) to subscribe to an event / notification when the allocation reaches the number of PDU sessions per network slice per PLMN (e.g., per first S-NSSAI). In one embodiment, the first S-NSSAI may be the first requested S-NSSAI. In one embodiment, the first S-NSSAI may be the first permitted S-NSSAI. In one embodiment, the first NSSAI may include the first S-NSSAI. In one embodiment, the first NSSAI may be the first requested NSSAI. In one embodiment, the first NSSAI may be the first permitted NSSAI. The Nnwdaf_AnalyticsSubscription_Subscribe message may include a parameter indicating the first S-NSSAI. In one embodiment, the Nnwdaf_AnalyticsSubscription_Subscribe message may include a parameter indicating the first NSSAI, and the first NSSAI may include the first S-NSSAI. For example, the NSSF may send the Nnwdaf_AnalyticsSubscription_Subscribe message to the NWDAF to subscribe to an event / notification when the allocation reaches the maximum number of PDU sessions for the first S-NSSAI. The network function (e.g., NWDAF, OAM) may receive a report message from one or more AMF / SMFs, and the report message may include the number of PDU sessions per network slice within the one or more AMF / SMFs. The network function may calculate the total number of PDU sessions per network slice for the PLMN.

[0248] The NSSF may receive, from a network function, a first message indicating that an allocation has been reached for the number of PDU sessions for a first S-NSSAI. In one embodiment, the first message may be an overload indication message. In one embodiment, the first message may be an allocation reached indication message. For example, the NWDAF may send an Nnwdaf_AnalyticsSubscription_Notify message to the NSSF indicating that an allocation has been reached for the maximum number of PDU sessions for a first S-NSSAI for a first PLMN. For example, the OAM may send an allocation reached indication message to the NSSF indicating that an allocation has been reached for the maximum number of PDU sessions for a first S-NSSAI for a first PLMN. The first message may include a first information element (IE) indicating a network slice (e.g., the first S-NSSAI). The first message may also include a second IE indicating that an allocation has been reached for the number of PDU sessions per network slice (e.g., the first S-NSSAI) per PLMN (e.g., the first PLMN). The first message may also include a third IE indicating the action of the NSSF with respect to the PDU sessions of a network slice (e.g., the first S-NSSAI) for a PLMN (e.g., the first PLMN). The action of the NSSF may be to reject the establishment of PDU sessions for a network slice (e.g., the first S-NSSAI) for a PLMN (e.g., the first PLMN). The action of the NSSF may be to determine an allowed S-NSSAI for the PDU sessions for a network slice (e.g., the first S-NSSAI) for a PLMN (e.g., the first PLMN).

[0249] In one example, the UE may send a NAS message including at least one of the following to the AMF: S-NSSAI (e.g., the first S-NSSAI), DNN, PDU session ID, request type, or N1 SM container (PDU session establishment request). The UE may start the PDU session establishment procedure requested by the UE by sending a NAS message including a PDU session establishment request message within the N1 SM container.

[0250] The PDU session establishment request message may include at least one of a PDU session ID, a requested PDU session type, or a requested SSC mode. In response to the message received from the UE, the AMF may select an SMF and send a message (e.g., a PDU session establishment request, a PDUSession_CreateSMContext request) including at least one of the following to the SMF: SUPI, DNN, S-NSSAI (e.g., the first S-NSSAI), and / or a network slice instance identifier, PDU session ID, AMF ID, request type, PCF identifier, preferred access, N1 SM container (PDU session establishment request), user location information, access type, PEI). By way of example, the PCF identifier may be an identifier, or an IP address, or an FQDN identifying the PCF.

[0251] In response to a message received from the AMF, the SMF may take one or more actions. In an exemplary action, the SMF may send a message (e.g., Nnssf_NSSelection_Get) requesting a network slice for a PLMN (e.g., the first PLMN) to the NSSF. The Nnssf_NSSelection_Get message may include network slice information (e.g., the first S-NSSAI) received from the AMF / UE. The Nnssf_NSSelection_Get message may include UE identification information (e.g., SUPI), DNN, and / or PDU session ID. In response to a message received from the SMF, the NSSF may take one or more actions. In an exemplary action, the NSSF may determine a second permitted S-NSSAI based on a first message received from a network function and a message received from the SMF (e.g., Nnssf_NSSelection_Get). For example, the NSSF may determine a second permitted S-NSSAI based on the first message and the first S-NSSAI. For example, based on the first S-NSSAI of the Nnssf_NSSelection_Get message, and / or the first S-NSSAI of the first message, and / or a second IE of the first message indicating that the maximum number of PDU sessions for the first S-NSSAI for the first PLMN has been reached, and / or a third IE of the first message indicating the NSSF's action for the PDU session of the first S-NSSAI, the NSSF may determine to reject a PDU session establishment request for the first S-NSSAI for the first PLMN.For example, based on a second IE of the first message indicating that the maximum number of PDU sessions for a first S-NSSAI (e.g., having a network slice type for URLLC) of a PDU session establishment request message, and / or the first S-NSSAI of the first message, and / or a first S-NSSAI for a first PLMN has been reached for allocation, and / or a third IE of the first message indicating an action of the NSSF for a PDU session of the first S-NSSAI (e.g., rejecting the PDU session and / or determining a second permitted S-NSSAI), the NSSF may determine a second permitted S-NSSAI (e.g., having a network slice type for MIoT) for a PDU session for the first PLMN. In an exemplary action, the NSSF may send a response message (e.g., Nnssf_NSSelection_Get Response) including the second permitted S-NSSAI, UE identification information, DNN, and / or PDU session ID to the SMF. The response message (e.g., Nnssf_NSSelection_Get Response) may include an action of the SMF. The action of the SMF may be to reject the PDU session establishment. The response message (e.g., Nnssf_NSSelection_Get Response) may include a network slice overload indication, and the network slice overload indication may indicate that a network slice (e.g., the first S-NSSAI) is overloaded. For example, the network slice overload indication may indicate that the network slice (e.g., the first S-NSSAI) is overloaded because the allocation has reached the number of PDU sessions for the PLMN (e.g., the first PLMN) (e.g., the maximum number of PDU sessions). The response message (e.g., Nnssf_NSSelection_Get Response) may include an allocation reached indication indicating that the allocation has reached the number of PDU sessions for the PLMN (e.g., the first PLMN) (e.g., the maximum number of PDU sessions).The response message (e.g., Nnssf_NSSelection_Get Response) may include the rejected S-NSSAI (e.g., the first S-NSSAI).

[0252] Based on the response message received from the NSF (e.g., Nnssf_NSSelection_Get Response) and / or the message received from the AMF (e.g., PDUSession_CreateSMContext request), the SMF may decide to reject the PDU session establishment, and / or the SMF may decide to send a second permitted S-NSSAI to the AMF / UE. For example, based on the SMF's action and / or the network slice overload indication and / or the allocation reach indication and / or the rejected S-NSSAI and / or the second permitted S-NSSAI, the SMF may decide to reject the PDU session establishment for the first S-NSSAI. For example, based on the rejected S-NSSAI and / or the second permitted S-NSSAI, the SMF may decide to send the second permitted S-NSSAI to the UE. The SMF may send a PDU session response message to the UE via the AMF. In an embodiment, the PDU session response message may be a PDU session commitment message. The PDU session commitment message may include the second permitted S-NSSAI indicating that the second permitted S-NSSAI may be used for the PDU session for the first PLMN. In an embodiment, the PDU session response message may be a PDU session rejection message. The PDU session rejection message may include a cause value indicating that the PDU session was rejected because the maximum number of PDU sessions for the first S-NSSAI for the first PLMN has been reached. The PDU session rejection message may include the second permitted S-NSSAI and / or a retry indicator indicating that the UE may retry to establish a second (new) PDU session for the second permitted S-NSSAI for the first PLMN.

[0253] In response to a message received from the AMF / SMF, the SMF may take one or more actions. In an exemplary action, the UE may use a second permitted S-NSSAI for the PDU session based on the PDU session acceptance message and / or the second permitted S-NSSAI. For example, the UE may use a second permitted S-NSSAI (e.g., of the eMBB type) for an application service (e.g., video) on the PDU session. In an exemplary action, the UE may determine a second requested S-NSSAI based on the PDU session rejection message and / or the second permitted S-NSSAI. For example, the UE may determine the second requested S-NSSAI based on the second permitted S-NSSAI and / or a retry indicator. The UE may send a second PDU session establishment request message containing the second requested S-NSSAI to the AMF / SMF.

[0254] In the existing art, the UE may send a message to access the network and / or establish a connection with a base station in the network. The message may include a request for a specific network slice. One or more base stations may receive the message and set up an RRC connection of the UE with the base station via the requested network slice. One or more base stations may complete the RRC connection. When the connection of the RRC connection is successful, the UE can communicate with the core network via the base station, for example, using NAS messages.

[0255] A network slice can access multiple UEs via various (R)ANs while the UE has potentially established multiple PDU sessions. In one example, the network may be configured to guarantee / maintain a certain level of QoS for the users of the network slice. For example, it guarantees / maintains that the UEs connected to the network slice have a delay below a specific threshold. When multiple UEs establish multiple PDU sessions for the same network slice, the network's ability to achieve the guaranteed level of QoS is impaired. Under certain conditions, the core network control plane (e.g., AMF, SMF) can prevent network slice overload by rejecting UE connection and / or PDU session establishment requests. For example, when the UE receives a notification that the NAS setup request has been rejected, the UE setup is delayed and the user experience is impaired. The AMF and / or SMF that receive the PDU session establishment request may determine that the allocation for the number of PDU sessions for the network slice has been reached. The AMF and / or SMF may send a NAS message rejecting the establishment of one or more PDU sessions to the UE. In an embodiment, this process may result in the establishment of PDU sessions exceeding the allocation when the UE is roaming in a visited network different from the home network. In an embodiment, this process may result in early rejection of PDU session establishment before allocation when the UE is roaming in a visited network different from the home network. In one example, this may be the result of having different configurations and / or numbers of PDU sessions in the home network compared to the visited network. Existing technologies may not efficiently support the control of the number of UEs and / or PDU sessions per network slice. As a result, the QoS for wireless devices in the network may deteriorate, for example, when the wireless device is roaming in a visited network.

[0256] Exemplary embodiments of the present disclosure may provide an enhanced mechanism for a first network function (e.g., SMF and / or NSSF) to efficiently support control of the number of UEs per network slice and / or the number of PDU sessions, for example, to establish a PDU session for a UE when the UE is roaming within a visited network. In an exemplary embodiment, a visited session management function (SMF) may send a request from a radio device for a packet data unit (PDU) session in a network slice to a home SMF. The home SMF may determine that it has reached an assignment for at least one PDU session of the network slice. The visited SMF may receive from the home SMF a cause value indicating that it has reached the network slice assignment for the number of PDU sessions for the network slice. In one example, the visited SMF may receive from the home SMF a second network slice for at least one PDU session. According to the exemplary embodiments, the visited SMF and / or the home SMF may appropriately determine whether to reject a PDU session because it has reached the assignment. In one example, the visited SMF may send the cause value to the radio device. Exemplary embodiments may enable a network function to send a NAS rejection message to a radio device based on an updated number of PDU sessions per network slice and the configuration of the home and / or visited SMF when the radio device is roaming. In one example, the network function may send a second network slice to the radio device. The radio device may send a message to a visited network function (e.g., visited SMF) to establish at least one PDU session in the second network slice. Exemplary embodiments enhance the QoS of PDU sessions in a network slice by accurately implementing the assignment of the number of PDU sessions per network slice in a radio network when the radio device is roaming in the visited network.Examples of embodiments may enable the maintenance of a connection to the first network slice even when reaching the allocation by using the second network slice.

[0257] Exemplary embodiments of the present disclosure may provide an enhanced mechanism for supporting control of the number of UEs per network slice and / or the number of PDU sessions in a roaming scenario. When a network function receives the HPLMN NSSAI from a visited network (e.g., visited SMF) and reaches the threshold number of UEs and / or the threshold number of PDU sessions of the HPLMN NSSAI, exemplary embodiments of the present disclosure may provide an enhanced mechanism that enables the home SMF to determine the home PLMN permitted NSSAI and provide the home PLMN permitted NSSAI to the visited SMF.

[0258] FIG. 25 shows an exemplary call flow that may include one or more actions. In one example, the home PLMN (HPLMN) SMF (H-SMF) may send a message (e.g., Nnwdaf_AnalyticsSubscription_AIsubscribe) to a network function (e.g., NWDAF, OAM) to subscribe to an event / notification when it reaches an allocation for the number of UEs per PLMN (e.g., HPLMN) per network slice (e.g., per first HPLMN S-NSSAI), and / or for the number of PDU sessions per PLMN (e.g., HPLMN) per network slice (e.g., per first HPLMN S-NSSAI). The first HPLMN S-NSSAI may be a network slice defined by the HPLMN. In one embodiment, the first HPLMN S-NSSAI may be the first HPLMN permitted S-NSSAI. For example, the H-SMF may send an Nnwdaf_AnalyticsSubscription_Subscribe message to the NWDAF to subscribe to an event / notification when it reaches an allocation for the maximum number of UEs for the first HPLMN S-NSSAI, and / or when it reaches an allocation for the maximum number of PDU sessions for the first HPLMN S-NSSAI. The network function (e.g., NWDAF, OAM) may receive a report message from one or more H-SMFs, and the report message may include the number of UEs and / or the number of PDU sessions per network slice within the one or more H-SMFs. The network function may calculate the total number of UEs and / or the total number of PDU sessions per network slice (first HPLMN S-NSSAI) for the PLMN (e.g., HPLMN).

[0259] The H-SMF may receive, from a network function, a first message indicating that an allocation has been reached for the number of UEs for a first HPLMN S-NSSAI and / or for the number of PDU sessions for a first HPLMN S-NSSAI. In one embodiment, the first message may be an overload indication message. In one embodiment, the first message may be an allocation reached indication message. For example, the NWDAF may send an Nnwdaf_AnalyticsSubscription_Notify message to the H-SMF indicating that an allocation has been reached for the maximum number of UEs for a first HPLMN S-NSSAI for an HPLMN and / or for the maximum number of PDU sessions for a first HPLMN S-NSSAI for an HPLMN. For example, the OAM may send an allocation reached indication message to the H-SMF indicating that an allocation has been reached for the maximum number of UEs for a first HPLMN S-NSSAI for an HPLMN and / or for the maximum number of PDU sessions for a first HPLMN S-NSSAI for an HPLMN. The first message may include a first information element (IE) indicating a network slice (e.g., the first HPLMN S-NSSAI). The first message may also include a second IE indicating that an allocation has been reached for the number of UEs per network slice (e.g., for the first HPLMN S-NSSAI) per PLMN (e.g., for an HPLMN). The first message may also include a third IE indicating that an allocation has been reached for the number of PDU sessions per network slice (e.g., for the first HPLMN S-NSSAI) per PLMN (e.g., for an HPLMN). The first message may also include a fourth IE indicating the action of the H-SMF for PDU sessions of a network slice (e.g., the first HPLMN S-NSSAI) for a PLMN (e.g., an HPLMN). The action of the H-SMF may be to reject PDU session establishment for a network slice (e.g., the first HPLMN S-NSSAI) for a PLMN (e.g., an HPLMN).The action of the H-SMF may be to determine the allowed S-NSSAI for a PDU session for a network slice (e.g., the first HPLMN S-NSSAI) with respect to a PLMN (e.g., the HPLMN).

[0260] In one example, the UE may send a NAS message including at least one of the following to the AMF: S-NSSAI (e.g., the first VPLMN S-NSSAI and / or the first HPLMN S-NSSAI), DNN, PDU session ID, request type, or N1 SM container (PDU session establishment request). The UE may initiate the PDU session establishment procedure requested by the UE by sending a NAS message including a PDU session establishment request message within the N1 SM container.

[0261] The PDU session establishment request message may include at least one of a PDU session ID, a requested PDU session type, or a requested SSC mode. In response to the message received from the UE, the AMF may select a V-SMF and / or an H-SMF. The AMF may send a message (e.g., a PDU session establishment request, a PDUSession_CreateSMContext request) including at least one of the following to the V-SMF: SUPI, DNN, S-NSSAI (e.g., the first VPLMN S-NSSAI and / or the first HPLMN S-NSSAI) and / or a network slice instance identifier, PDU session ID, AMF ID, request type, H-SMF identifier, preferred access, N1 SM container (PDU session establishment request), user location information, access type, PEI).

[0262] In response to a message received from the AMF, the V-SMF may send a message (e.g., PDU session establishment request, Nsmf_PDUSession_Create Request) to the H-SMF. The PDU session establishment request / Nsmf_PDUSession_Create Request message may include at least one of a first VPLMN S-NSSAI, a first HPLMN S-NSSAI, a SUPI, a GPSI (if available), a V-SMF SM Context ID, a DNN, a PDU session ID, a V-SMF ID, a V-CN-Tunnel-Info, a PDU session type, a PCO, the number of packet filters, user location information, an access type, a PCF ID, and / or an AMF ID. In one embodiment, the PDU session establishment request / Nsmf_PDUSession_Create Request message may include a first VPLMN NSSAI and / or a first HPLMN NSSAI, the first VPLMN NSSAI may include a first VPLMN S-NSSAI, and the first HPLMN NSSAI may include a first HPLMN S-NSSAI.

[0263] In response to a message received from the V-SMF, the H-SMF may take one or more actions. In an exemplary action, based on a first message received from a network function and / or a message received from the V-SMF, the H-SMF may decide to reject the PDU session establishment and / or the H-SMF may determine a second H-PLMN permitted S-NSSAI. For example, the H-SMF may determine the second HPLMN permitted S-NSSAI based on the first message (e.g., the first HPLMN S-NSSAI in the first message) and / or the first HPLMN S-NSSAI and / or the first VPLMN S-NSSAI. In one embodiment, the H-SMF may determine a second H-PLMN permitted NSSAI that includes the second H-PLMN permitted S-NSSAI.

[0264] For example, based on the first HPLMN S-NSSAI of the PDU session establishment request / Nsmf_PDUSession_Create Request message, and / or the first HPLMN S-NSSAI of the first message, and / or the second IE of the first message indicating that the allocation has reached the maximum number of UEs for the first HPLMN S-NSSAI for the HPLMN, and / or the third IE of the first message indicating that the allocation has reached the maximum number of PDU sessions for the first HPLMN S-NSSAI for the HPLMN, and / or the fourth IE of the first message indicating the action of the H-SMF for the PDU session of the first HPLMN S-NSSAI, the H-SMF may determine to reject the PDU session establishment request for the first HPLMN S-NSSAI for the HPLMN and / or the first VPLMN S-NSSAI for the VPLMN. For example, based on the first HPLMN S-NSSAI and / or the first VPLMN S-NSSAI of the PDU session establishment request / Nsmf_PDUSession_Create Request message, and / or the first HPLMN S-NSSAI of the first message, and / or the second IE of the first message indicating that the allocation has reached the maximum number of UEs for the first HPLMN S-NSSAI for the HPLMN, and / or the third IE of the first message indicating that the allocation has reached the maximum number of PDU sessions for the first HPLMN S-NSSAI for the HPLMN, and / or the fourth IE of the first message indicating the action of the H-SMF for the PDU session of the first HPLMN S-NSSAI, the H-SMF may determine the second HPLMN permitted S-NSSAI for the HPLMN and / or the first VPLMN S-NSSAI for the VPLMN.

[0265] For example, based on the first HPLMN S-NSSAI of the PDU session establishment request message (e.g., having a network slice type of MIoT), and / or the first VPLMN S-NSSAI (e.g., having a network slice type of MIoT), and / or the first HPLMN S-NSSAI of the first message, and / or the third IE of the first message indicating that the allocation has reached the maximum number of PDU sessions for the first HPLMN S-NSSAI with respect to the HPLMN, and / or the fourth IE of the first message indicating the action of the H-SMF for the PDU session, the H-SMF may determine a second HPLMN permitted S-NSSAI (e.g., having a network slice type of V2X) I for the PDU session with respect to the HPLMN and / or for the first VPLMN S-NSSAI with respect to the VPLMN.

[0266] In an exemplary action, in response to the decision, the H-SMF may send a PDU session response message to the V-SMF. The PDU session response message may include the rejected S-NSSAI (e.g., the first HPLMN S-NSSAI and / or the first VPLMN S-NSSAI). In an embodiment, the PDU session response message may include the rejected NSSAI, and the rejected NSSAI includes the rejected S-NSSAI. In an embodiment, the PDU session response message may be a PDU session commitment message. The PDU session commitment message may include a second HPLMN permitted S-NSSAI indicating that the second HPLMN permitted S-NSSAI can be used for the PDU session of the HPLMN. In an embodiment, the PDU session response message may be a PDU session rejection message. For example, the PDU session rejection message may include a cause value indicating that the PDU session was rejected because the maximum number of UEs for the first HPLMN S-NSSAI for the HPLMN has been reached. For example, the PDU session rejection message may include a cause value indicating that the PDU session was rejected because the maximum number of PDU sessions for the first HPLMN S-NSSAI for the HPLMN has been reached. The PDU session rejection message may include a second HPLMN permitted S-NSSAI and / or a retry indicator indicating that the UE may retry to establish a second (new) PDU session for the second HPLMN permitted S-NSSAI for the HPLMN and / or for the first VPLMN S-NSSAI for the VPLMN.

[0267] In response to a message received from the H-SMF, the V-SMF may take one or more actions. In an exemplary action, based on the message received from the H-SMF, the V-SMF may determine a mapping of a second VPLMN permitted NSSAI and / or a permitted NSSAI. The second VPLMN permitted NSSAI may include a second VPLMN permitted S-NSSAI. The mapping of the permitted NSSAI may include a second HPLMN permitted S-NSSAI. For example, based on the second HPLMN permitted S-NSSAI, and / or a retry indicator, and / or a cause value indicating that the PDU session was rejected, and / or a first VPLMN S-NSSAI, the V-SMF may determine a mapping of a second VPLMN permitted NSSAI and / or a permitted NSSAI. In an example of an action, the V-SMF may send a PDU session response message to the AMF / UE. In an embodiment, the PDU session response message may be a PDU session commitment message. The PDU session commitment message may include a mapping of a second VPLMN permitted NSSAI and / or a permitted NSSAI. The mapping of the permitted NSSAI indicates that the second VPLMN permitted NSSAI and / or the mapping of the second VPLMN permitted NSSAI and / or the permitted NSSAI can be used for a PDU session for the VPLMN and / or the HPLMN. In an embodiment, the PDU session response message may be a PDU session rejection message. The PDU session rejection message may include a cause value indicating that the PDU session was rejected because the allocation reached the maximum number of PDU sessions for the first HPLMN S-NSSAI for the HPLMN. The PDU session rejection message may include a second VPLMN permitted NSSAI, and / or a mapping of a permitted NSSAI, and / or a retry indicator indicating that the UE may retry to establish a second (new) PDU session for the second VPLMN permitted NSSAI for the VPLMN and / or the mapping of the permitted NSSAI for the HPLMN.

[0268] In response to a message received from the AMF / V-SMF, the UE may take one or more actions. In an exemplary action, based on the PDU session acceptance message and / or the mapping of the second VPLMN permitted NSSAI and / or the permitted NSSAI, the UE may use the second VPLMN permitted NSSAI and / or the mapping of the permitted NSSAI for the PDU session. In an action of an embodiment, based on the PDU session rejection message and / or the second VPLMN permitted NSSAI and / or the mapping of the permitted NSSAI, the UE may determine a second mapping of the second requested S-NSSAI and / or the permitted NSSAI for a second new PDU session. For example, the UE may determine the second requested S-NSSAI based on the second VPLMN permitted S-NSSAI and / or the retry indicator. The UE may send a second PDU session establishment request message including the second mapping of the second requested S-NSSAI and / or the permitted NSSAI to the AMF / V-SMF.

[0269] Figure 26 shows an exemplary call flow that may include one or more actions. In one example, the Home PLMN (HPLMN) Network Slice Selection Function (H-NSSF) may send a message (e.g., Nnwdaf_AnalyticsSubscription_AIsubscribe) to a network function (e.g., NWDAF, OAM) to subscribe to an event / notification when it reaches the allocation for the number of UEs per PLMN (e.g., HPLMN) per network slice (e.g., per first HPLMN S-NSSAI), and / or when it reaches the allocation for the number of PDU sessions per PLMN (e.g., HPLMN) per network slice (e.g., per first HPLMN S-NSSAI). The first HPLMN S-NSSAI may be a network slice defined by the HPLMN. In one embodiment, the first HPLMN S-NSSAI may be the first HPLMN permitted S-NSSAI. For example, the H-NSSF may send an Nnwdaf_AnalyticsSubscription_Subscribe message to the NWDAF to subscribe to an event / notification when it reaches the allocation for the maximum number of UEs for the first HPLMN S-NSSAI, and / or when it reaches the allocation for the maximum number of PDU sessions for the first HPLMN S-NSSAI. The network function (e.g., NWDAF, OAM) may receive a report message from one or more H-SMFs, and the report message may include the number of UEs and / or the number of PDU sessions per network slice within the one or more H-SMFs. The network function may calculate the total number of UEs and / or the total number of PDU sessions per network slice (first HPLMN S-NSSAI) for the PLMN (e.g., HPLMN).

[0270] The H-NSSF may receive, from a network function, a first message indicating that an allocation has been reached for the number of UEs for a first HPLMN S-NSSAI and / or for the number of PDU sessions for a first HPLMN S-NSSAI. In one embodiment, the first message may be an overload indication message. In one embodiment, the first message may be an allocation reached indication message. For example, the NWDAF may send an Nnwdaf_AnalyticsSubscription_Notify message to the H-NSSF indicating that an allocation has been reached for the maximum number of UEs for a first HPLMN S-NSSAI for an HPLMN and / or for the maximum number of PDU sessions for a first HPLMN S-NSSAI for an HPLMN. For example, the OAM may send an allocation reached indication message to the H-NSSF indicating that an allocation has been reached for the maximum number of UEs for a first HPLMN S-NSSAI for an HPLMN and / or for the maximum number of PDU sessions for a first HPLMN S-NSSAI for an HPLMN. The first message may include a first information element (IE) indicating a network slice (e.g., a first HPLMN S-NSSAI). The first message may also include a second IE indicating that an allocation has been reached for the number of UEs per network slice (e.g., for a first HPLMN S-NSSAI) per PLMN (e.g., for an HPLMN). The first message may also include a third IE indicating that an allocation has been reached for the number of PDU sessions per network slice (e.g., for a first HPLMN S-NSSAI) per PLMN (e.g., for an HPLMN). The first message may also include a fourth IE indicating the action of the H-NSSF for PDU sessions of a network slice (e.g., a first HPLMN S-NSSAI) for a PLMN (e.g., an HPLMN). The action of the H-NSSF may be to reject PDU session establishment for a network slice (e.g., a first HPLMN S-NSSAI) for a PLMN (e.g., an HPLMN).The action of the H-NSSF may be to determine the allowed S-NSSAIs for a PDU session for a network slice (e.g., the first HPLMN S-NSSAI) with respect to a PLMN (e.g., the HPLMN).

[0271] In one example, the UE may send a NAS message including at least one of the following to the AMF: S-NSSAI (e.g., the first VPLMN S-NSSAI and / or the first HPLMN S-NSSAI), DNN, PDU session ID, request type, or N1 SM container (PDU session establishment request). The UE may initiate the PDU session establishment procedure requested by the UE by sending a NAS message including a PDU session establishment request message within the N1 SM container.

[0272] The PDU session establishment request message may include at least one of a PDU session ID, a requested PDU session type, or a requested SSC mode. In response to the message received from the UE, the AMF may select a V-SMF and / or an H-SMF. The AMF may send a message (e.g., a PDU session establishment request, a PDUSession_CreateSMContext request) including at least one of the following to the V-SMF: SUPI, DNN, S-NSSAI (e.g., the first VPLMN S-NSSAI and / or the first HPLMN S-NSSAI) and / or network slice instance identifier, PDU session ID, AMF ID, request type, H-SMF identifier, priority access, N1 SM container (PDU session establishment request), user location information, access type, PEI).

[0273] In response to a message received from the AMF, the V-SMF may send a message (e.g., PDU session establishment request, Nsmf_PDUSession_Create Request) to the H-SMF. The PDU session establishment request / Nsmf_PDUSession_Create Request message may include at least one of a first VPLMN S-NSSAI, a first HPLMN S-NSSAI, a SUPI, a GPSI (if available), a V-SMF SM Context ID, a DNN, a PDU session ID, a V-SMF ID, a V-CN-Tunnel-Info, a PDU session type, a PCO, a number of packet filters, user location information, an access type, a PCF ID, and / or an AMF ID. In one embodiment, the PDU session establishment request / Nsmf_PDUSession_Create Request message may include a first VPLMN NSSAI and / or a first HPLMN NSSAI, the first VPLMN NSSAI may include the first VPLMN S-NSSAI, and the first HPLMN NSSAI may include the first HPLMN S-NSSAI.

[0274] In response to a message received from the V-SMF, the H-SMF may take one or more actions. In an exemplary action, the H-SMF may send a message (e.g., Nnssf_NSSelection_Get) requesting a network slice for a PLMN (e.g., HPLMN) to the H-NSSF. The Nnssf_NSSelection_Get message may include network slice information received from the V-SMF (e.g., the first HPLMN S-NSSAI and / or the first VPLMN S-NSSAI). The Nnssf_NSSelection_Get message may include UE identification information (e.g., SUPI), DNN, and / or PDU session ID. In response to a message received from the H-SMF, the H-NSSF may perform one or more actions. In an exemplary action, the H-NSSF may determine a second HPLMN permitted S-NSSAI based on the first message received from the network function and the message received from the H-SMF (e.g., Nnssf_NSSelection_Get). In one embodiment, the H-NSSF may determine a second HPLMN permitted NSSAI, where the second HPLMN permitted NSSAI includes the second HPLMN permitted S-NSSAI. For example, the NSSF may determine the second HPLMN permitted S-NSSAI based on the first message and the first HPLMN S-NSSAI.For example, based on the second IE of the first message indicating that the allocation has reached the maximum number of UEs for the first VPLMN S-NSSAI of the Nnssf_NSSelection_Get message and / or the first HPLMN S-NSSAI of the Nnssf_NSSelection_Get message and / or the first HPLMN S-NSSAI of the first message and / or the first HPLMN S-NSSAI for the HPLMN, and / or the third IE of the first message indicating that the allocation has reached the maximum number of PDU sessions for the first HPLMN S-NSSAI for the HPLMN, and / or the fourth IE of the first message indicating the action of the H-NSSF for the PDU session of the first HPLMN S-NSSAI, the H-NSSF may determine to reject the PDU session establishment request for the first HPLMN S-NSSAI for the HPLMN and / or the first VPLMN S-NSSAI for the VPLMN. For example, based on the first VPLMN S-NSSAI (e.g., having a network slice type for URLLC), and / or the first HPLMN S-NSSAI (e.g., having a network slice type for URLLC), and / or the first HPLMN S-NSSAI of the first message, and / or the second IE of the first message indicating that the allocation has reached the maximum number of UEs for the first HPLMN S-NSSAI for the HPLMN, and / or the fourth IE of the first message indicating the action of the H-NSSF for the PDU session (e.g., rejecting the PDU session and / or determining a second HPLMN permitted S-NSSAI) in the PDU session establishment request message, the H-NSSF may determine a second HPLMN permitted S-NSSAI (e.g., having a network slice type for MIoT) for the PDU session for the HPLMN. In an exemplary action, the H-NSSF may send a response message (e.g., Nnssf_NSSelection_Get Response) including the second HPLMN permitted S-NSSAI, UE identification information, DNN, and / or PDU session ID to the H-SMF.In one embodiment, the response message (e.g., Nnssf_NSSelection_Get Response) may include a second HPLMN permitted NSSAI. The response message (e.g., Nnssf_NSSelection_Get Response) may include an action of the H-SMF. The action of the H-SMF may be to reject the PDU session establishment. The response message (e.g., Nnssf_NSSelection_Get Response) may include a network slice overload indication, and the network slice overload indication may indicate that a network slice (e.g., the first HPLMN S-NSSAI) is overloaded. For example, the network slice overload indication may indicate that the network slice (e.g., the first HPLMN S-NSSAI) is overloaded because the number of PDU sessions for the HPLMN (e.g., the maximum number of PDU sessions) has reached the allocation. The response message (e.g., Nnssf_NSSelection_Get Response) may include an allocation reached indication indicating that the allocation for the number of PDU sessions of the HPLMN (e.g., the maximum number of PDU sessions) has been reached. The response message (e.g., Nnssf_NSSelection_Get Response) may include a rejected S-NSSAI (e.g., the first HPLMN S-NSSAI). In one embodiment, the response message (e.g., Nnssf_NSSelection_Get Response) may include a rejected NSSAI, and the rejected NSSAI includes the rejected S-NSSAI.

[0275] Based on the response message received from the H-NSSF (e.g., Nnssf_NSSelection_Get Response), and / or the message received from the V-SMF (e.g., PDU session establishment request, PDUSession_CreateSMContext request), the H-SMF may decide to reject the PDU session establishment, and / or the H-SMF may decide to send a second HPLMN permitted S-NSSAI to the V-SMF.

[0276] In an exemplary action, in response to the decision, the H-SMF may send a PDU session response message to the V-SMF. The PDU session response message may include a second rejected NSSAI, and the second rejected NSSAI includes a second rejected S-NSSAI. In one embodiment, the PDU session response message may include a second rejected S-NSSAI, and the second rejected S-NSSAI may include a first HPLMN S-NSSAI and / or a first VPLMN S-NSSAI. In an embodiment, the PDU session response message may be a PDU session commitment message. The PDU session commitment message may include a second HPLMN permitted S-NSSAI indicating that the second HPLMN permitted S-NSSAI can be used for the PDU session of the HPLMN. In an embodiment, the PDU session response message may be a PDU session rejection message. For example, the PDU session rejection message may include a cause value indicating that the PDU session was rejected because the maximum number of UEs for the first HPLMN S-NSSAI for the HPLMN was reached. For example, the PDU session rejection message may include a cause value indicating that the PDU session was rejected because the maximum number of PDU sessions for the first HPLMN S-NSSAI for the HPLMN was reached. The PDU session rejection message may include a second HPLMN permitted S-NSSAI and / or a retry indicator indicating that the UE may retry to establish a second (new) PDU session for the second HPLMN permitted S-NSSAI for the HPLMN and / or for the first VPLMN S-NSSAI for the VPLMN.

[0277] In response to a message received from the H-SMF, the V-SMF may take one or more actions. In an exemplary action, based on the message received from the H-SMF, the V-SMF may determine a mapping of a second VPLMN permitted NSSAI and / or a permitted NSSAI. The mapping of the permitted NSSAI may include a second HPLMN permitted S-NSSAI. For example, based on the second HPLMN permitted S-NSSAI, and / or a retry indicator, and / or a cause value indicating that the PDU session was rejected, and / or a first VPLMN S-NSSAI, the V-SMF may determine a mapping of a second VPLMN permitted NSSAI and / or a permitted NSSAI. In an example of an action, the V-SMF may send a PDU session response message to the AMF / UE. In an embodiment, the PDU session response message may be a PDU session commitment message. The PDU session commitment message may include a mapping of a second VPLMN permitted NSSAI and / or a permitted NSSAI. The mapping of the permitted NSSAI indicating that the second VPLMN permitted NSSAI and / or the mapping of the second VPLMN permitted NSSAI and / or the permitted NSSAI can be used for the PDU session for the VPLMN and / or the HPLMN. In an embodiment, the PDU session response message may be a PDU session rejection message. The PDU session rejection message may include a cause value indicating that the PDU session was rejected because the maximum number of PDU sessions for the first HPLMN S-NSSAI for the HPLMN has been reached. The PDU session rejection message may include a second VPLMN permitted NSSAI, and / or a mapping of a permitted NSSAI, and / or a retry indicator indicating that the UE may retry to establish a second (new) PDU session for the second VPLMN permitted NSSAI for the VPLMN and / or the mapping of the permitted NSSAI for the HPLMN.

[0278] In response to a message received from the AMF / V-SMF, the UE may take one or more actions. In an exemplary action, based on the PDU session commitment message and / or the mapping of the second VPLMN permitted NSSAI and / or the permitted NSSAI, the UE may use the mapping of the second VPLMN permitted NSSAI and / or the permitted NSSAI for the PDU session. In an action of the embodiment, based on the PDU session rejection message and / or the second VPLMN permitted NSSAI and / or the mapping of the permitted NSSAI, the UE may determine a second mapping of the second requested S-NSSAI and / or the permitted NSSAI for a second new PDU session. For example, the UE may determine the second requested S-NSSAI based on the second VPLMN permitted S-NSSAI and / or the retry indicator. The UE may send a second PDU session establishment request message including the second mapping of the second requested S-NSSAI and / or the permitted NSSAI to the AMF / V-SMF.

[0279] In one embodiment, the base station may receive, from a network function, a first message indicating that a first single network slice selection assistance information (S-NSSAI) is overloaded. In one embodiment, the base station may receive, from a radio device, a radio resource control (RRC) message for an RRC connection, and the RRC message includes the first S-NSSAI. In one embodiment, the base station may determine to release the RRC connection based on the first message and the first S-NSSAI. In one embodiment, the base station may send an RRC release message indicating that the first S-NSSAI is overloaded to the radio device.

[0280] In an exemplary embodiment, the first message may indicate that the first S-NSSAI is overloaded because the allocation for the number of UEs for the first S-NSSAI has been reached. In an exemplary embodiment, the RRC release message may include a release cause indicating that the first S-NSSAI is overloaded. In an exemplary embodiment, the RRC release message may include a release cause indicating that the first S-NSSAI is overloaded because the allocation for the number of UEs for the first S-NSSAI has been reached. In an exemplary embodiment, the first message may include at least one of an overload indication message, an allocation reached indication message, or an overload start message. In an exemplary embodiment, the first message may include a first information element (IE) indicating a network slice. In an exemplary embodiment, the first message may include a second IE indicating that the allocation for the number of UEs for the first S-NSSAI for a PLMN has been reached. In an exemplary embodiment, the first message may include a third IE indicating that the allocation for the number of PDU sessions for the first S-NSSAI for a PLMN has been reached. In an exemplary embodiment, the first message may include a fourth IE indicating an action of a base station for an RRC connection for the first S-NSSAI for a PLMN. In an exemplary embodiment, the action of the base station for the RRC connection may indicate releasing the RRC connection. In an exemplary embodiment, the RRC message may be an RRCSetupComplete message, and the RRCSetupComplete may include at least one of an RRC-TransactionIdentifier, a 5G-S-TMSI, an s-NSSAI-List IE, a selected PLMN-Identity IE, and / or a dedicatedNAS-Message. In an exemplary embodiment, the base station may further determine a rejected S-NSSAI for an RRC connection to a wireless device. In an exemplary embodiment, the base station may further determine a waiting time for the rejected S-NSSAI. In an exemplary embodiment, the RRC release message may include the rejected S-NSSAI.In an exemplary embodiment, the RRC release message may include a waiting time. In an exemplary embodiment, the wireless device may determine an action based on the RRC release message. In an exemplary embodiment, the action may be to establish a second (new) RRC connection with the base station. In an exemplary embodiment, the action may be to send a new RRC Setup Complete message to the base station. In an exemplary embodiment, the action may be for determining a second requested S-NSSAI. In an exemplary embodiment, the wireless device may send a new RRC Setup Complete message including the second requested S-NSSAI to the base station.

[0281] In one embodiment, the wireless device may send a first Radio Resource Control (RRC) message for an RRC connection to the base station, and the first RRC message includes a first S-NSSAI. In one embodiment, the wireless device may receive, from the base station, an RRC release message including a release cause indicating that the allocation has reached the number of UEs for the first S-NSSAI. In one embodiment, based on the release cause, the wireless device may determine a second requested S-NSSAI. In one embodiment, the wireless device may be able to send a second RRC message for a new RRC connection to the base station, and the second RRC message includes the second requested S-NSSAI.

[0282] In one embodiment, the base station may receive, from a network function, a first message indicating that a first single network slice selection assistance information (S-NSSAI) is overloaded. In one embodiment, the base station may receive, from a wireless device, a radio resource control (RRC) message for an RRC connection, and the RRC message includes the first S-NSSAI. In one embodiment, the base station may determine to release the RRC connection based on the first message and the first S-NSSAI. In one embodiment, the base station may send, to the wireless device, an RRC release message indicating that the first S-NSSAI is overloaded. In an exemplary embodiment, the network function may include at least one of an access and mobility management function (AMF), a network data analytics function (NWDAF), or an operation, administration, and maintenance (OAM). In an exemplary embodiment, the RRC release message may include a parameter indicating that the first S-NSSAI is overloaded. In an exemplary embodiment, the RRC release message may indicate that the cause of the release is that the first S-NSSAI is overloaded. In an exemplary embodiment, the first message may further include a second parameter indicating an allocation reached for the maximum number of PDU sessions per network slice for the first S-NSSAI. In an exemplary embodiment, the RRC message may further include one or more second S-NSSAIs.

[0283] In one embodiment, the base station may receive, from a network function, a first message indicating that an allocation has been reached for the number of UEs for a first single network slice selection assistance information (S-NSSAI). In one embodiment, the base station may receive, from a radio device, a radio resource control (RRC) message for an RRC connection, and the RRC message includes the first S-NSSAI. In one embodiment, the base station may determine to release the RRC connection based on the first message and the first S-NSSAI. In one embodiment, the base station may transmit, to the radio device, an RRC release message including a release cause indicating that an allocation has been reached for the number of UEs for the first S-NSSAI. In an exemplary embodiment, the network function may include at least one of an access and mobility management function (AMF), a network data analytics function (NWDAF), or an operation, administration, and maintenance (OAM). In an exemplary embodiment, the first message may further include a second parameter indicating that an allocation has been reached for the maximum number of PDU sessions per network slice for the first S-NSSAI. In an exemplary embodiment, the RRC message may further include one or more second S-NSSAIs.

[0284] In one embodiment, the base station may receive, from a network function, a first message indicating that an allocation has been reached for the number of PDU sessions for a first single network slice selection assistance information (S-NSSAI). In one embodiment, the base station may receive, from a radio device, a radio resource control (RRC) message for an RRC connection, and the RRC message includes the first S-NSSAI. In one embodiment, the base station may determine to release the RRC connection based on the first message and the first S-NSSAI. In one embodiment, the base station may transmit, to the radio device, an RRC release message including a release cause indicating that an allocation has been reached for the number of PDU sessions for the first S-NSSAI.

[0285] In one embodiment, the wireless device may send a first PDU session establishment request message including a first requested S-NSSAI to the session management function (SMF) via the access and mobility management function (AMF). In one embodiment, the wireless device may receive, from the SMF, a PDU session rejection message including a second permitted S-NSSAI. In one embodiment, the wireless device may determine a second requested S-NSSAI based on the PDU session rejection message and the second permitted S-NSSAI. In one embodiment, the wireless device may send a second PDU session establishment request message including the second requested S-NSSAI to the SMF.

[0286] In one embodiment, the session management function (SMF) may receive, from a network function, a first message indicating that an allocation has reached the limit for the number of packet data unit (PDU) sessions for a first single network slice selection assistance information (S-NSSAI). In one example, the SMF may be able to receive, from the access and mobility management function (AMF), a PDU session establishment request message including the first S-NSSAI. In one embodiment, the SMF may determine a second permitted S-NSSAI based on the first message and the first S-NSSAI. In one embodiment, in response to the determination, the SMF may send, to the wireless device via the AMF, a PDU session response message including the second permitted S-NSSAI. In an exemplary embodiment, the PDU session response message may be a PDU session rejection message. In an exemplary embodiment, the PDU session response message may be a PDU session acceptance message. In an exemplary embodiment, the PDU session response message may include a retry indicator. In an exemplary embodiment, the retry indicator may indicate that the wireless device is to establish a PDU session with the second permitted S-NSSAI.

[0287] In one embodiment, a Network Slice Selection Function (NSSF) may receive, from a Session Management Function (SMF), a first message indicating that an allocation has been reached for the number of Packet Data Unit (PDU) sessions for a first single Network Slice Selection Assistance Information (S-NSSAI). In one embodiment, the NSSF may determine a second permitted S-NSSAI based on the first message and the first S-NSSAI. In one embodiment, the NSSF may send a response message including the second permitted S-NSSAI to the SMF.

[0288] In one embodiment, a Session Management Function (SMF) may receive, from an Access and Mobility Management Function (AMF), a Packet Data Unit (PDU) session creation request message including a first single Network Slice Selection Assistance Information (S-NSSAI). In one embodiment, the SMF may be from a network function, a first parameter indicating that an allocation has been reached for the number of PDU sessions for the first S-NSSAI, and a second permitted S-NSSAI. In one embodiment, the SMF may determine to reject the PDU session based on the first parameter and the second permitted S-NSSAI. In one embodiment, the SMF may send a PDU session rejection message including a retry indicator and the second permitted NSSAI to the radio device via the AMF. In an exemplary embodiment, the network function may be a Network Slice Selection Function (NSSF).

[0289] In one embodiment, the visited session management function (V-SMF) may send a PDU session creation request message to the home SMF (H-SMF), including a first single network slice selection assistance information (S-NSSAI) for the visited public land mobile network (V-PLMN) and a second S-NSSAI for the home PLMN (H-PLMN). In one embodiment, the V-SMF may receive a PDU session rejection message from the H-SMF, including a retry indicator and an H-PLMN permitted NSSAI. In one embodiment, based on the H-PLMN permitted NSSAI, the V-SMF may determine the V-PLMN permitted NSSAI and the mapping of the permitted NSSAIs. In one embodiment, the V-SMF may send a PDU session rejection message to the wireless device, including the retry indicator, the V-PLMN permitted NSSAI, and the mapping of the permitted NSSAIs.

[0290] In one embodiment, the home session management function (H-SMF) may receive a first message from a network function indicating that the allocation has reached the number of packet data unit (PDU) sessions for the first single network slice selection assistance information (S-NSSAI) of the home PLMN. In one embodiment, the H-SMF may receive a PDU session creation request message from the V-SMF, including the first S-NSSAI of the H-PLMN and the first S-NSSAI of the V-PLMN. In one embodiment, the H-SMF may determine the H-PLMN permitted S-NSSAI based on the first message, the first S-NSSAI of the H-PLMN, and the first S-NSSAI of the V-PLMN. In one embodiment, the H-SMF may send a PDU session rejection message to the V-SMF, including the retry indicator and the H-PLMN permitted S-NSSAI.

[0291] In one embodiment, a Home Network Slice Selection Function (H-NSSF) may receive, from a network function, a first message indicating that an assignment has been reached for the number of Packet Data Unit (PDU) sessions for a first single Network Slice Selection Assistance Information (S-NSSAI) of a Home Public Land Mobile Network (H-PLMN). In one embodiment, the H-NSSF may receive, from a Home Session Management Function (H-SMF), a first message including the first S-NSSAI of the H-PLMN and the first S-NSSAI of a Visited PLMN (V-PLMN). In one embodiment, the H-NSSF may determine a H-PLMN permitted S-NSSAI based on the first message, the first S-NSSAI of the H-PLMN, and the first S-NSSAI of the V-PLMN. In one embodiment, the H-NSSF may send a response message including the H-PLMN permitted S-NSSAI to the H-SMF.

[0292] According to various embodiments, for example, one or more devices such as a wireless device, an off-network wireless device, a base station, a core network device, etc. can be used in a system. One or more devices may be configured to perform a particular operation or action by software, firmware, hardware, or a combination thereof installed on the one or more devices that perform an action or cause an action to be performed on the one or more devices during operation. One or more computer programs may be configured to perform a particular action or actions by including instructions that cause the device to perform an action when executed by a data processing device. Exemplary embodiments of actions are illustrated in the accompanying figures and specification. Further embodiments can be created by combining features from various embodiments.

[0293] As used herein, the articles "a" and "an" and similar terms are to be construed as meaning "at least one" and "one or more". As used herein, the term "may" is to be construed as meaning "for example, may be". In other words, the term "may" indicates that the statement following the term "may" is an example of one of a plurality of suitable possibilities and may or may not be used with respect to one or more of the various embodiments. If A and B are sets and all elements of A are also elements of B, then A is called a subset of B. Only non-empty sets and subsets are considered herein. For example, the possible subsets of B = {cell 1, cell 2} are {cell 1}, {cell 2}, and {cell 1, cell 2}.

[0294] As used herein, various embodiments are disclosed. Limitations, features, and / or elements from the disclosed exemplary embodiments can be combined to create additional embodiments within the scope of the present disclosure.

[0295] As used herein, various embodiments are disclosed. Limitations, features, and / or elements from the disclosed exemplary embodiments can be combined to create additional embodiments within the scope of the present disclosure.

[0296] As used in this specification, a parameter (information element: IE) can include one or more objects, and one of those objects can include one or more other objects. For example, if parameter (IE) N includes parameter (IE) M, parameter (IE) M includes parameter (IE) K, and parameter (IE) K includes parameter (information element) J, then, for example, N includes K and N includes J. In an embodiment, when one or more messages include a plurality of parameters, it means that a parameter among the plurality of parameters is included in at least one of the one or more messages, but does not have to be included in one of the one or more messages.

[0297] Many of the elements described in the disclosed embodiments may be implemented as modules. A module is defined herein as a separable element that performs a defined function and has a defined interface to other elements. The modules described in this disclosure may be implemented in hardware, software combined with hardware, firmware, wetware (e.g., hardware having biological elements), or combinations thereof, some of which are behaviorally equivalent. For example, a module may be implemented as a software routine described in a computer language configured to be executed on a hardware machine (such as C, C++, Fortran, Java®, Basic, Matlab®, etc.) or in Simulink, Stateflow, GNU Octave, or LabVIEW MathScript. Additionally, it may be possible to implement a module using physical hardware incorporating discrete or programmable analog, digital, and / or quantum hardware. Examples of programmable hardware include computers, microcontrollers, microprocessors, application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), complex programmable logic devices (CPLDs). Computers, microcontrollers, and microprocessors are programmed using languages such as assembly, C, C++. FPGAs, ASICs, and CPLDs are often programmed using hardware description languages (HDLs) such as VHSIC Hardware Description Language (VHDL) or Verilog, which configure connections between internal hardware modules with fewer programmable device functions. Finally, it is important to emphasize that the above techniques are often used in combination to achieve the results of functional modules.

[0298] Although various embodiments have been described above, it should be understood that they are presented by way of example and not limitation. It will be apparent to those skilled in the art that various changes in form and detail can be made without departing from the spirit and scope. Indeed, after reading the above specification, ways to implement alternative embodiments will be apparent to those skilled in the relevant art. Accordingly, the present embodiments should not be limited by any of the above exemplary embodiments. In particular, for illustrative purposes, it should be noted that the above description focuses on examples using 5G AN. However, those skilled in the art will recognize that embodiments of the present invention can be implemented in one or more legacy systems or systems including LTE. The disclosed methods and systems can be implemented in wireless or wired systems. The features of the various embodiments presented in this disclosure can be combined. One or more features (methods or systems) of one embodiment can be implemented in other embodiments. A limited number of exemplary combinations are shown to illustrate to those skilled in the art the possibility of features that can be combined in various embodiments to create enhanced transmission and reception systems and methods.

[0299] Furthermore, it should be understood that any diagrams highlighting functions and advantages are presented for illustrative purposes. The disclosed architecture is flexible and configurable so that it can be utilized in ways other than those shown. For example, any action listed in any flowchart can be reordered in some embodiments or used only optionally.

Claims

1. A method comprising: An access destination session management function (SMF) of an access destination public land mobile network (PLMN) transmits a request of the wireless device for a packet data unit (PDU) session in a first network slice among a plurality of network slices of the home PLMN to a home SMF of the home PLMN of the wireless device; The access destination SMF receives, from the home SMF, a message indicating rejection of the request by the home SMF, the message including a cause value indicating that the network slice allocation of the home PLMN has reached the number of PDU sessions for the first network slice; A method comprising the above.

2. The method according to claim 1, further comprising: the access destination SMF receives, from the wireless device, a PDU session establishment request including the request for the PDU session in the first network slice.

3. The method according to claim 2, wherein the PDU session establishment request includes one or more network slice identifiers including a single network slice selection assistance information (S-NSSAI) of the first network slice.

4. The method according to any one of claims 1 to 3, wherein the message includes a PDU session response message.

5. The method according to any one of claims 1 to 4, further comprising: the access destination SMF transmits a message to the wireless device, the message indicating the rejection and including the cause value.

6. An access destination session management function (SMF), the access destination SMF comprising one or more processors and a memory storing instructions, the instructions, when executed by the one or more processors, cause the access destination SMF to perform the method according to any one of claims 1 to 5.

7. A non-transitory computer-readable medium, the non-transitory computer-readable medium comprising instructions, the instructions, when executed by one or more processors, cause the one or more processors to perform the method according to any one of claims 1 to 5.

8. A method comprising: The home session management function (SMF) of a wireless device's home public land mobile network (PLMN) receives, from a visited SMF of a visited PLMN, a request of the wireless device to establish a packet data unit (PDU) session in a first network slice among a plurality of network slices of the home PLMN, wherein the home SMF transmits to the visited SMF a message indicating rejection of the request by the home SMF, the message including a cause value indicating that the network slice allocation of the home PLMN has reached the number of PDU sessions for the first network slice, A method comprising the above.

9. The method according to claim 8, further comprising the home SMF transmitting to a network function a message to subscribe to an event of the network slice allocation.

10. The method according to claim 9, further comprising the home SMF receiving from a network function a message notifying the event.

11. The method according to any one of claims 9 to 10, wherein the event includes that the network slice allocation has reached the number of PDU sessions for the first network slice.

12. The method according to any one of claims 8 to 11, wherein the message includes a PDU session response message.

13. A home session management function (SMF), wherein the home SMF comprises one or more processors and a memory storing instructions, and when the instructions are executed by the one or more processors, causes the home SMF to perform the method according to any one of claims 8 to 12.

14. A non-transitory computer-readable medium, wherein the non-transitory computer-readable medium comprises instructions, and when the instructions are executed by one or more processors, causes the one or more processors to perform the method according to any one of claims 8 to 12.

15. A system, A visited session management function (SMF), wherein the visited SMF comprises one or more processors and a memory for storing instructions, and when the instructions are executed by the one or more processors, sending a request of the wireless device for a packet data unit (PDU) session in a first network slice among a plurality of network slices of the home PLMN to the home SMF of the home PLMN of the wireless device; receiving, from the home SMF, a message indicating rejection of the request by the home SMF, the message including a cause value indicating that the network slice allocation of the home PLMN has reached the number of PDU sessions for the first network slice; causing the above to be performed by the visited SMF, a visited SMF; A home SMF, wherein the home SMF comprises one or more processors and a memory for storing instructions, and when the instructions are executed by the one or more processors, receiving, from the visited SMF, the request of the wireless device for establishing the PDU session in the first network slice; sending, to the visited SMF, the message, the message including the cause value indicating that the network slice allocation of the home PLMN has reached the number of the PDU sessions for the first network slice; causing the above to be performed by the home SMF, a home SMF; A system comprising.

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