Method and apparatus for a radio interface between a user equipment associated with a radio access network and another user equipment in a communication system

Abstract

An apparatus, comprising: at least one processor; and at least one memory including computer program code, the at least one memory and the computer program code being configured to, with the at least one processor, cause the apparatus to perform: receiving a message at a core network for a first user equipment via a radio interface between the first user equipment and a second user equipment; and sending at least some of the content of the message to a core network for the second user equipment.

Description

Technical Field

[0001] The present disclosure relates to an apparatus, a method, and a computer program, and in particular, but not limited to, an apparatus, a method, and a computer program for a radio interface between a user equipment associated with a radio access network and another user equipment in a system. Background Art

[0002] A communication system may involve a user equipment sending and / or receiving data and / or control signaling to / from a core network via a radio interface with another user equipment served by a radio access network. Summary of the Invention

[0003] An apparatus includes: components for preparing a message at a first user equipment, and components for transmitting the message via a radio interface between the first user equipment and a second user equipment, where the message at least includes content addressed to the core network for the first user equipment, and where the core network for the first user equipment is independent of the core network for the second user equipment.

[0004] The message may at least include content that is transparent to the core network for the second user equipment.

[0005] The message may at least include a layer 2 message, such as an access stratum (AS) message, and the content addressed to the core network for the first user equipment at least includes layer 3 content, such as a non-access stratum (NAS) message..

[0006] An apparatus includes: components for receiving a message at the core network for the first user equipment at least via a radio interface between the first user equipment and a second user equipment; and components for sending at least some of the content of the message to the core network for the second user equipment.

[0007] The content sent to the core network for the second user equipment may at least include content that is transparent to the core network for the first user equipment.

[0008] The content sent to the core network for the second user equipment may include a layer 2 message, such as an access stratum (AS) message, and at least include layer 3 content, such as a non-access stratum (NAS) message.

[0009] The content sent to the core network for the second user equipment may include an Ethernet packet data unit.

[0010] An apparatus includes: components for receiving, at a core network for a first user equipment, a message from a core network for a second user equipment, wherein the second user equipment is connected to the core network for the first equipment at least via a radio interface between the first user equipment and the second user equipment; and components for forwarding the message to a radio access network for the first user equipment.

[0011] The message may include an Ethernet packet data unit.

[0012] An apparatus includes: components for receiving, at a core network for a first user equipment, a message at least via a core network for a second user equipment and a radio interface between the first user equipment and the second user equipment; and components for recovering data and / or signaling from the message.

[0013] The message may at least include: content transparent to the core network of the second user equipment.

[0014] The message may include a layer 2 message, such as an access stratum (AS) message, including layer 3 content, such as a non-access stratum (NAS) message.

[0015] The message may include an Ethernet packet data unit.

[0016] An apparatus includes: components for preparing, at a core network for a first user equipment, a message for the first user equipment; and components for sending the message to a core network for a second user equipment, wherein the first user equipment is connected to the core network for the first user equipment via a core network for the second user equipment and a radio interface between the first user equipment and the second user equipment.

[0017] The message may at least include: content at least transparent to the core network of the second user equipment.

[0018] The message may at least include a layer 2 message, such as an access stratum (AS) message, at least including layer 3 content, such as a non-access stratum (NAS) message.

[0019] The message may include an Ethernet packet data unit.

[0020] An apparatus includes: components for preparing a message at a first device; and components for transmitting the message via a radio interface between the first user equipment and the second user equipment; wherein the message includes information for selecting a mobility management function entity for the first user equipment.

[0021] An apparatus comprises: means for receiving a message at least via a radio interface between a first user equipment and a second user equipment, the message comprising information for selecting a mobility management function entity for the second user equipment; and means for selecting a mobility management function entity for the second user equipment, wherein the mobility management function of the second user equipment is independent of the mobility management function of the first user equipment.

[0022] An apparatus comprises: at least one processor; and at least one memory including computer program code, the at least one memory and the computer program code being configured to, with the at least one processor, cause the apparatus to perform: preparing a message at the first user equipment and transmitting the message via a radio interface between the first user equipment and the second user equipment, wherein the message at least comprises content addressed to a core network for the first user equipment, and wherein the core network for the first user equipment is independent of the core network for the second user equipment.

[0023] The message can at least comprise content that is at least transparent to the core network for the second user equipment.

[0024] The message can at least comprise a layer 2 message, such as an access stratum (AS) message, and the content addressed to the core network for the first user equipment at least comprises layer 3 content, such as a non-access stratum (NAS) message.

[0025] An apparatus comprises: at least one processor; and at least one memory including computer program code, the at least one memory and the computer program code being configured to, with the at least one processor, cause the apparatus to perform: receiving a message at the core network for the first user equipment via at least a radio interface between the first user equipment and the second user equipment; and sending at least some of the content of the message to the core network for the second user equipment.

[0026] The content sent to the core network for the second user equipment can at least comprise content that is at least transparent to the core network for the first user equipment.

[0027] The content sent to the core network for the second user equipment can comprise a layer 2 message, such as an access stratum (AS) message, including at least layer 3 content, such as a non-access stratum (NAS) message.

[0028] The content sent to the core network for the second user equipment can comprise an Ethernet packet data unit.

[0029] An apparatus comprises: at least one processor; and at least one memory comprising computer program code, the at least one memory and the computer program code being configured to, with the at least one processor, cause the apparatus to perform: receiving, at a core network for a first user equipment, a message from a core network of a second user equipment, wherein the second user equipment is connected to the core network for the first equipment via a radio interface between the first user equipment and the second user equipment; and forwarding the message to a radio access network for the first user equipment.

[0030] The message may comprise an Ethernet packet data unit.

[0031] An apparatus comprises: at least one processor; and at least one memory comprising computer program code, the at least one memory and the computer program code being configured to, with the at least one processor, cause the apparatus to perform: receiving, at a core network for a first user equipment, a message at least via a core network for a second user equipment and a radio interface between the first user equipment and the second user equipment; and recovering data and / or signaling from the message.

[0032] The message may at least comprise content that is transparent at least to the core network for the second user equipment.

[0033] The message may comprise a layer 2 message, such as an access stratum (AS) message, comprising layer 3 content, such as a non-access stratum (NAS) message.

[0034] The message may comprise an Ethernet packet data unit.

[0035] An apparatus comprises: at least one processor; and at least one memory, comprising computer program code, the at least one memory and the computer program code being configured to, with the at least one processor, cause the apparatus to perform: preparing, at a core network for a first user equipment, a message for the first user equipment; and sending the message to a core network for a second user equipment, wherein the first user equipment is connected to the core network for the first user equipment via a core network for the second user equipment and a radio interface between the first user equipment and the second user equipment.

[0036] The message may at least comprise content that is transparent at least to the core network for the second user equipment.

[0037] The message may at least comprise a layer 2 message, such as an access stratum (AS) message, at least comprising layer 3 content, such as a non-access stratum (NAS) message.

[0038] The message may comprise an Ethernet packet data unit.

[0039] An apparatus comprises: at least one processor; and at least one memory including computer program code, the at least one memory and the computer program code being configured to, with the at least one processor, cause the apparatus to perform: preparing a message at a first device; and transmitting the message via a radio interface between a first user equipment and a second user equipment; wherein the message includes information for selecting a mobility management function entity for the first user equipment.

[0040] An apparatus comprises: at least one processor; and at least one memory including computer program code, the at least one memory and the computer program code being configured to, with the at least one processor, cause the apparatus to perform: receiving a message at least via a radio interface between a first user equipment and a second user equipment, the message including information for selecting a mobility management function entity for the second user equipment; and selecting a mobility management function entity for the second user equipment, wherein the mobility management function of the second user equipment is independent of the mobility management function of the first user equipment.

[0041] A method comprises: preparing a message at a first user equipment, and transmitting the message via a radio interface between the first user equipment and a second user equipment, wherein the message at least includes content addressed to a core network for the first user equipment, and wherein the core network for the first user equipment is independent of the core network for the second user equipment.

[0042] The message can at least include content that is at least transparent to the core network for the second user equipment.

[0043] The message can at least include a layer 2 message, such as an access stratum (AS) message, and the content addressed to the core network for the first user equipment at least includes layer 3 content, such as a non-access stratum (NAS) message.

[0044] A method comprises: at a core network for a first user equipment, receiving a message at least via a radio interface between the first user equipment and a second user equipment; and sending at least some of the content of the message to a core network for the second user equipment.

[0045] The content sent to the core network for the second user equipment can at least include content that is at least transparent to the core network for the first user equipment.

[0046] The content sent to the core network for the second user equipment can include a layer 2 message, such as an access stratum (AS) message, and at least includes layer 3 content, such as a non-access stratum (NAS) message.

[0047] The content sent to the core network for the second user equipment can include an Ethernet packet data unit.

[0048] A method includes: at a core network for a first user equipment, receiving a message from a core network for a second user equipment, wherein the second user equipment is connected to the core network for the first equipment at least via a radio interface between the first user equipment and the second user equipment; and forwarding the message to a radio access network for the first user equipment.

[0049] The message may include an Ethernet packet data unit.

[0050] A method includes: at a core network for a first user equipment, receiving a message at least via a core network for a second user equipment and a radio interface between the first user equipment and the second user equipment; and recovering data and / or signaling from the message.

[0051] The message may at least include content that is transparent to at least the core network for the second user equipment.

[0052] The message may include a layer 2 message, such as an access stratum (AS) message, including layer 3 content, such as a non-access stratum (NAS) message.

[0053] The message may include an Ethernet packet data unit.

[0054] A method includes: at a core network for a first user equipment, preparing a message for the first user equipment; and sending the message to a core network for a second user equipment, wherein the first user equipment is connected to the core network for the first user equipment via a core network for the second user equipment and a radio interface between the first user equipment and the second user equipment.

[0055] The message may at least include content that is transparent to at least the core network for the second user equipment.

[0056] The message may at least include a layer 2 message, such as an access stratum (AS) message, at least including layer 3 content, such as a non-access stratum (NAS) message.

[0057] The message may include an Ethernet packet data unit.

[0058] A method includes: preparing a message at a first device; and transmitting the message via a radio interface between the first user equipment and the second user equipment; wherein the message includes information for selecting a mobility management function entity for the first user equipment.

[0059] A method includes: receiving a message at least via a radio interface between a first user equipment and a second user equipment, the message including information for selecting a mobility management function entity for the second user equipment; and selecting a mobility management function entity for the second user equipment, wherein the mobility management function of the second user equipment is independent of the mobility management function of the first user equipment.

[0060] A computer-readable medium includes program instructions stored on the computer-readable medium for performing: preparing a message at the first user equipment, and transmitting the message via a radio interface between the first user equipment and the second user equipment, wherein the message at least includes content addressed to the core network for the first user equipment, and wherein the core network for the first user equipment is independent of the core network of the second user equipment.

[0061] A computer-readable medium includes program instructions stored on the computer-readable medium for performing: at the core network of the first user equipment, receiving a message at least via a radio interface between the first user equipment and the second user equipment; and sending at least some of the content of the message to the core network for the second user equipment.

[0062] A computer-readable medium includes program instructions stored on the computer-readable medium for performing: at the core network for the first user equipment, receiving a message from the core network for the second user equipment, wherein the second user equipment is connected to the core network for the first device at least via a radio interface between the first user equipment and the second user equipment; and forwarding the message to the radio access network for the first user equipment.

[0063] A computer-readable medium includes program instructions stored on the computer-readable medium for performing: at the core network for the first user equipment, receiving a message at least via the core network for the second user equipment and a radio interface between the first user equipment and the second user equipment; and recovering data and / or signaling from the message.

[0064] A computer-readable medium includes program instructions stored on the computer-readable medium for performing: at the core network for the first user equipment, preparing a message for the first user equipment; and sending the message to the core network for the second user equipment, wherein the first user equipment is connected to the core network for the first user equipment via the core network for the second user equipment and a radio interface between the first user equipment and the second user equipment.

[0065] A computer-readable medium includes program instructions stored on the computer-readable medium for performing: preparing a message at a first device; and transmitting the message via a radio interface between a first user device and a second user device; wherein the message includes information for selecting a mobility management function entity for the first user device.

[0066] A computer-readable medium includes program instructions stored on the computer-readable medium for performing: receiving a message at least via a radio interface between a first user device and a second user device, the message including information for selecting a mobility management function entity for the second user device; and selecting a mobility management function entity for the second user device, wherein the mobility management function of the second user device is independent of the mobility management function of the first user device.

[0067] A non-transitory computer-readable medium includes program instructions stored on the non-transitory computer-readable medium for performing: preparing a message at a first user device, and transmitting the message via a radio interface between the first user device and a second user device, wherein the message at least includes content addressed to a core network for the first user device, and wherein the core network for the first user device is independent of the core network for the second user device.

[0068] A non-transitory computer-readable medium includes program instructions stored on the non-transitory computer-readable medium for performing: receiving a message at a core network for a first user device at least via a radio interface between the first user device and a second user device; and sending at least some of the content of the message to a core network for the second user device.

[0069] A non-transitory computer-readable medium includes program instructions stored on the non-transitory computer-readable medium for performing: receiving a message at a core network for a first user device from a core network for a second user device, wherein the second user device is connected to the core network for the first device at least via a radio interface between the first user device and the second user device; and forwarding the message to a radio access network for the first user device.

[0070] A non-transitory computer-readable medium includes program instructions stored on the non-transitory computer-readable medium for performing: receiving a message at a core network for a first user device at least via a core network for a second user device and a radio interface between the first user device and the second user device; and recovering data and / or signaling from the message.

[0071] A non-transitory computer-readable medium includes program instructions stored on the non-transitory computer-readable medium for performing: preparing a message at a core network for a first user equipment; and sending the message to a core network for a second user equipment, wherein the first user equipment is connected to the core network for the first user equipment via the core network for the second user equipment and a radio interface between the first user equipment and the second user equipment.

[0072] A non-transitory computer-readable medium includes program instructions stored on the non-transitory computer-readable medium for performing: preparing a message at a first device; and transmitting the message via a radio interface between a first user equipment and a second user equipment; wherein the message includes information for selecting a mobility management function entity for the first user equipment.

[0073] A non-transitory computer-readable medium includes program instructions stored on the non-transitory computer-readable medium for performing: receiving at least via a radio interface between a first user equipment and a second user equipment a message that includes information for selecting a mobility management function entity for the second user equipment; and selecting a mobility management function entity for the second user equipment, wherein the mobility management function of the second user equipment is independent of the mobility management function of the first user equipment.

[0074] A computer program includes computer-executable code that when run on at least one processor is configured to cause a device to at least: prepare a message at a first user equipment, and transmit the message via a radio interface between the first user equipment and the second user equipment, wherein the message at least includes content addressed to a core network for the first user equipment, and wherein the core network for the first user equipment is independent of the core network for the second user equipment.

[0075] A computer program includes computer-executable code that when run on at least one processor is configured to cause a device to at least: receive at a core network for a first user equipment, at least via a radio interface between the first user equipment and the second user equipment, a message; and send at least some of the content of the message to a core network for the second user equipment.

[0076] A computer program includes computer-executable code that when run on at least one processor is configured to cause a device to at least: receive at a core network for a first user equipment a message from a core network for a second user equipment, wherein the second user equipment is connected to a core network for the first device at least via a radio interface between the first user equipment and the second user equipment; and forward the message to a radio access network for the first user equipment.

[0077] A computer program includes computer-executable code that, when run on at least one processor, is configured to cause a device to at least: receive a message at a core network for a first user equipment via at least a core network for a second user equipment and a radio interface between the first user equipment and the second user equipment; and recover data and / or signaling from the message.

[0078] A computer program includes computer-executable code that, when run on at least one processor, is configured to cause a device to at least: prepare a message for a first user equipment at a core network for the first user equipment; and send the message to a core network of a second user equipment, wherein the first user equipment is connected to the core network for the first user equipment via a core network for the second user equipment and a radio interface between the first user equipment and the second user equipment.

[0079] A computer program includes computer-executable code that, when run on at least one processor, is configured to cause a device to at least: prepare a message at a first device; and transmit the message via a radio interface between the first user equipment and the second user equipment; wherein the message includes information for selecting a mobility management function entity for the first user equipment.

[0080] A computer program includes computer-executable code that, when run on at least one processor, is configured to cause a device to at least: receive a message via at least a radio interface between the first user equipment and the second user equipment, the message including information for selecting a mobility management function entity for the second user equipment; and select a mobility management function entity for the second user equipment, wherein the mobility management function of the second user equipment is independent of the mobility management function of the first user equipment.

[0081] A non-transitory tangible storage medium includes program instructions stored thereon for performing at least one of the above methods.

[0082] A device includes: at least one processor; and at least one memory including computer program code, the at least one memory and the computer program code being configured to, with the at least one processor, cause the device to perform: prepare a message at a first user equipment, and transmit the message via a radio interface between the first user equipment and the second user equipment, wherein the message at least includes content addressed to a core network for the first user equipment, and wherein the core network for the first user equipment is independent of the core network for the second user equipment.

[0083] An apparatus comprises: at least one processor; and at least one memory including computer program code, the at least one memory and the computer program code being configured to, with the at least one processor, cause the apparatus to perform: receiving a message at a core network for a first user equipment via at least a radio interface between the first user equipment and a second user equipment; and sending at least some of the content of the message to a core network for the second user equipment.

[0084] An apparatus comprises: receiving circuitry for receiving a message at a core network for a first user equipment from a core network for a second user equipment, wherein the second user equipment is connected to the core network for the first equipment via at least a radio interface between the first user equipment and the second user equipment; and forwarding circuitry for forwarding the message to a radio access network for the first user equipment.

[0085] An apparatus comprises: receiving circuitry for receiving a message at a core network for a first user equipment via at least a core network for the second user equipment and a radio interface between the first user equipment and the second user equipment; and recovery circuitry for recovering data and / or signaling from the message.

[0086] An apparatus comprises: preparation circuitry for preparing a message for a first user equipment at a core network for the first user equipment; and sending circuitry for sending the message to a core network for the second user equipment, wherein the first user equipment is connected to the core network for the first user equipment via a core network for the second user equipment and a radio interface between the first user equipment and the second user equipment.

[0087] An apparatus comprises: preparation circuitry for preparing a message at a first device; and transmission circuitry for transmitting the message via a radio interface between the first user equipment and the second user equipment; wherein the message includes information for selecting a mobility management function entity for the first user equipment.

[0088] An apparatus comprises: receiving circuitry for receiving a message via at least a radio interface between the first user equipment and the second user equipment, the message including information for selecting a mobility management function entity for the second user equipment; and selection circuitry for selecting a mobility management function entity for the second user equipment, wherein the mobility management function of the second user equipment is independent of the mobility management function of the first user equipment.

[0089] Above, many different aspects have been described. It should be recognized that any combination of two or more of the above aspects can provide additional aspects.

[0090] Also described in the following detailed description and the appended claims are various other aspects. Description of the Drawings

[0091] Some example embodiments will now be described in further detail by way of example with reference to the following examples and drawings, in which:

[0092] Figure 1 A representation of a system architecture according to some example embodiments is shown;

[0093] Figure 2 A representation of a user plane and control plane protocol stack according to some example embodiments is shown;

[0094] Figure 3 A representation of a process according to some example embodiments is shown;

[0095] Figures 4a to 4g A method according to some example embodiments is shown;

[0096] Figure 5 A representation of a system architecture according to some example embodiments is shown;

[0097] Figure 6 A representation of a user plane and control plane protocol stack according to some example embodiments is shown;

[0098] Figure 7 A representation of a process according to some example embodiments is shown;

[0099] Figure 8 A representation of a control device according to some example embodiments is shown;

[0100] Figure 9 A representation of a device according to some example embodiments is shown; and

[0101] Figure 10 A representation of a non - volatile storage medium according to some example embodiments is shown. Detailed Description of the Embodiments

[0102] Referring to Figure 1 and Figure 2 , according to some example embodiments, a user equipment (remote UE102) does not have its own radio interface to the radio access network and relies on the radio interface between the remote UE102 and another user equipment (relay UE 104), and the radio interface between the relay UE 104 and the radio access network 106.

[0103] According to some example embodiments, the relay 104 forwards all user plane and control plane traffic of the remote UE 102 to / from the remote UE 102 using a layer 2 connection (e.g., an Ethernet PDU (Packet Data Unit) session).

[0104] According to some example embodiments, there is a core network (5G-CN remote 118) for a remote UE that is separate from and independent of a core network (5G-CN relay 116) for a relay UE 104. The core network 116 for the relay UE includes a set of interoperable core network entities, which includes an access mobility function entity (AMF) 110, a session management function (SMF) entity (not shown), and a user plane function entity (UPF) 108. The core network 118 for the remote UE 102 also includes a separate set of interoperable core network entities, including an access mobility function entity (AMF) 114, a session management function (SMF) entity (not shown), and a user plane function entity (UPF) 112.

[0105] According to some example embodiments, there is an N1 interface between the remote UE 102 and the core network 118 for the remote UE. This N1 interface allows layer 3 content (e.g., non-access stratum (NAS) messages) to be transparent to, for example, the relay UE core network 116, and the content is transmitted between the remote UE 102 and the core network 118 of the remote UE 102 via the relay UE network 116.

[0106] In Figure 1 FIG., block 120 represents a layer 2 Ethernet PDU session via which layer 3 content (e.g., non-access stratum (NAS) messages) is transmitted between the remote UE 102 and the core network 118 of the remote UE 102.

[0107] According to some example embodiments, for traffic relayed between the relay UE 104 and the UPF relay 110, a normal IP type PDU session is used instead of an Ethernet type PDU session:

[0108] According to this alternative, the relay UE 104 performs IP routing / NAT; the UPF relay 110 performs IP routing; the remote UE 102 is assigned a local IP address; and the non-access stratum (NAS) of the remote UE 102 is over IP.

[0109] Figure 3 FIG. shows a remote UE attachment procedure according to some example embodiments.

[0110] Operation 1): According to 3GPP TS 23.502, the relay UE 104 creates a PDU session for the remote UE 102 using the PDU type Ethernet.

[0111] Operation 2) Create a PC5 interface between the remote UE 102 and the relay UE 104, and the core network 116 for the relay UE 104 assigns an AMF to the remote UE 102: The remote UE 102 provides the relay UE 104 with the information required for the remote UE 102 to select an AMF via the PC5 interface (radio interface) between the remote UE 102 and the relay UE. For example, an example of such information is slice information, globally unique temporary ID (GUTI); the relay UE 104 forwards this information received from the remote UE 102 to the core network of the relay UE 104 via the radio interface between the relay UE 104 and the radio access network (e.g., 5G base station GnB), which enables the core network 116 of the relay UE 104 to select a "remote AMF" for the remote UE 102. An entity (e.g., policy charging function entity) in the core network 116 of the relay UE 104 selects an AMF for the remote UE 102, and the core network 116 of the relay UE 104 provides the Ethernet MAC address of the AMF selected for the remote UE 102 to the relay UE 104; and the relay UE 104 forwards this information to the remote UE 102.

[0112] Operation 2b): The UPF 108 of the relay UE 104 configures a forwarding rule for the traffic between the remote UE 102 and the remote AMF 118. Other examples use a simple Ethernet bridge without this forwarding rule.

[0113] Operation 3) The remote UE 102 communicates with the AMF 114 selected for the remote UE 102 in the previous operation via Ethernet using NAS (via the PC5 interface (radio interface) between the remote UE 102 and the relay UE 104, and via the PDU session of the relay UE 104) to register (this includes the authentication of the remote UE 102), and then creates a PDU session for the data traffic of the remote UE 102. From the perspective of the relay UE 104, the RAN 106, and the relay CN 116, this user data is the user data to be forwarded (protected by NAS security). The AMF 114 of the remote UE 102 performs the AMF tasks of the remote UE 102 (including authentication, IP address allocation), and configures a forwarding rule for the relay UE 104 of the PDU session of the remote UE 102 in the UPF. Other examples use a simple Ethernet bridge without these forwarding rules.

[0114] Operation 4): The data session for the remote UE is forwarded via the PC5 interface (radio interface between the remote UE 102 and the relay 104) and via the L2 PDU bearer for the relay UE 104. The UPF 108 of the relay UE 104 and the relay UE 104 can perform some mapping of QoS flows.

[0115] According to an alternative example, operation 2) involves the radio access network entity (e.g., 5G gNB) 106 selecting an AMF for the remote UE 102. The radio access network entity 106 makes this selection without storing the relay UE context in the radio access network entity 106. The UPF 108 for the relay UE 104 is typically close to the gNB 106, and when the remote UE 102 switches from the PC5 interface (radio interface with the relay UE 104) to the Uu interface (radio interface with the radio access network node (gNB)), the gNB to which the remote UE 102 switches is not far from the gNB 106 to continue serving the relay UE 104, and thus the gNB 106 of the relay UE 104 can select an appropriate AMF for the remote UE 102.

[0116] If the relay UE 104 enters the idle / inactive mode, the relay UE 104 can be paged when there is downlink traffic for the remote UE 102.

[0117] In the case of a loss of the Uu or PC5 connection, the AMF 110 for the relay UE 104 notifies the AMF 114 of the remote UE 102.

[0118] The mobility of the remote UE 102 is supported because the remote UE 102 is assigned to core network entities (AMF, SMF, UPF) 112, 114 that are independent of the core network entities 108, 110 assigned to the relay UE 104, and these independent core network entities 112, 114 assigned to the remote UE act as anchors during the mobility between the direct network connection (Uu radio interface between the remote UE 102 and the RAN 106) and the relay connection (via the PC5 radio interface between the remote UE 102 and the relay UE 104, and the Uu radio interface between the relay UE 104 and the RAN 106). This also enables the relay UE 104 to support remote UEs 102 using different core networks, e.g., due to different home public land mobile networks (HPLMNs) of the remote UE 102.

[0119] For example, the security of the core network 116 of the relay UE 104 for monitoring the message content of the remote UE 102 is good because the remote UE 102 performs authentication with the network via NAS, and the signaling between the remote UE 102 and the core network 118 of the remote UE 102 is protected by NAS security. The control plane (NAS) connection (including authentication, mobility, and session management) between the remote UE 102 and the core network 118 of the remote UE 102 is independent of the control plane connection between the relay UE 104 and the core network 116 for the relay UE 104.

[0120] When using an Ethernet - type connection, by performing Ethernet bridging instead of IP routing and NAT, the relay UE 104 can avoid assigning a local IPv4 address or IPv6 prefix to the remote UE 102.

[0121] The control and user - plane traffic of the remote UE 102 are forwarded in a transparent manner as the user - plane traffic of the relay UE 104 through the Ethernet (Layer 2) type of the PDU session of the relay UE 104.

[0122] Reference Figure 4a , Figure 4a shows the uplink operation of the remote UE 102 according to some example embodiments.

[0123] In step 400, the operation may include: preparing a message at the remote UE 102.

[0124] In step 402, the operation may include: transmitting the message through the radio interface between the remote UE 102 and the relay UE 104, where the message includes at least content addressed to the core network 118 of the remote UE, and where the core network of the remote UE is independent of the core network used for the relay UE.

[0125] According to some example embodiments, the message includes at least content that is transparent to the core network of the relay UE 104.

[0126] According to some example embodiments, the message includes at least a Layer 2 message, such as an access stratum (AS) message, and the content addressed to the core network 118 of the remote UE 102 includes at least Layer 3 content, such as a non - access stratum (NAS) message.

[0127] Reference Figure 4b , Figure 4b shows the uplink operation of the core network 116 for the relay UE 104 according to some example embodiments.

[0128] In step 404, the operation may include: receiving the message at the core network 116 for the relay UE via at least the radio interface between the relay UE 104 and the remote UE 102.

[0129] In step 406, the operation may include sending at least some of the content of the message to the core network 118 for the remote UE 102.

[0130] According to some example embodiments, the content sent to the core network 118 for the remote UE 102 includes at least content that is transparent to the core network 116 of the relay UE 104.

[0131] According to some example embodiments, the content sent to the core network 118 for the remote UE 102 includes layer 2 messages, such as access stratum (AS) messages, and at least includes layer 3 content, such as non-access stratum (NAS) messages.

[0132] According to some example embodiments, the content sent to the core network 118 for the remote UE 102 includes Ethernet packet data units.

[0133] Reference Figure 4c , Figure 4c shows the downlink operation of the core network 116 for the relay UE 104 according to some example embodiments.

[0134] In step 408, the operation may include: receiving, at the core network 116 for the relay UE 104, a message from the core network 118 for the remote UE 102, wherein the remote UE 102 is connected to the core network 116 for the relay UE 104 via at least a radio interface between the relay UE 104 and the remote UE 102.

[0135] In step 410, the operation may include: forwarding the message to the radio access network 106 for the relay UE 104.

[0136] According to some example embodiments, the message includes Ethernet packet data units.

[0137] Reference Figure 4d , Figure 4d shows the uplink operation of the core network 118 for the remote UE 102 according to some example embodiments.

[0138] In step 412, the operation may include: receiving, at the core network 118 for the remote UE 102, a message at least via the core network 116 for the relay UE 104 and a radio interface between the remote UE 102 and the relay UE 104.

[0139] In step 414, the operation may include recovering data and / or signaling from the message.

[0140] According to some example embodiments, the message at least includes content that is transparent to at least the core network 116 for the relay UE.

[0141] According to some example embodiments, the message includes layer 2 messages, such as access stratum (AS) messages, including layer 3 content, such as non-access stratum (NAS) messages.

[0142] According to some example embodiments, the message includes Ethernet packet data units.

[0143] Reference Figure 4e ,Figure 4e Shows the downlink operation of the core network 118 for the remote UE 102 according to some example embodiments.

[0144] In step 416, the operation may include: preparing a message for the remote UE 102 at the core network 118 for the remote UE 102.

[0145] In step 418, the operation may include: sending the message to the core network 116 for the relay UE 104, wherein the remote UE 102 is connected to the core network 118 for the remote UE 102 via the core network 116 for the relay UE 104 and the radio interface between the remote UE 102 and the relay 104.

[0146] According to some example embodiments, the message includes at least content that is at least transparent to the core network 116 of the relay UE 104.

[0147] According to some example embodiments, the message includes at least a layer 2 message, such as an access stratum (AS) message, including at least layer 3 content, such as a non-access stratum (NAS) message.

[0148] According to some example embodiments, the message includes an Ethernet packet data unit.

[0149] Reference Figure 4f , Figure 4f Shows the operation of the remote UE 102 according to some example embodiments.

[0150] In step 420, the operation may include preparing a message at the remote UE 102.

[0151] In step 422, the operation may include transmitting the message through the radio interface between the remote UE 102 and the relay UE 104, wherein the message includes information for selecting a mobility management function entity for the remote UE 102.

[0152] Reference Figure 4g , Figure 4g Shows the operation of the core network 116 of the relay UE 104 according to some example embodiments.

[0153] In step 424, the operation may include receiving at least via the core network 116 for the relay UE 104 and the radio interface between the remote UE and the relay UE a message that includes information for selecting a mobility management function entity for the remote UE 102.

[0154] In step 426, the operation may include: selecting a mobility management function entity for the remote UE 102, wherein the mobility management function for the remote UE 102 is independent of the mobility management function for the relay UE 104.

[0155] According to some example embodiments, the ProSe 5G UE-to-network relay entity 102 (relay UE) provides a function that supports the connection of a remote UE to the network for both public safety services and commercial services (e.g., interactive services) (see Figure 5 ). The remote UE 102 successfully establishes a PC5 link to the relay UE 104. The remote UE 102 can be within the NG-RAN coverage or outside the NG-RAN coverage.

[0156] Some example embodiments provide service confidentiality (e.g., when not provided by the higher layer / application layer), and IP@ protection in mobility between direct 5GC access (via Uu connected to the NG RAN) and 5GC access via the relay UE 104.

[0157] Some example embodiments reuse untrusted access to the 5G core network (5GC), which can be reused for 5G core network (5GC) access to the public land mobile network (PLMN) via the stand-alone non-public network (SNPN) entity and the non-3GPP interworking function (N3IWF) entity. According to some example embodiments, the N3IWF entity processes the 5G Prose remote UE 102 in the same way as a non-3GPP (N3GPP) UE.

[0158] Figure 6 A representation of a protocol stack for N3IWF-enabled ProSe 5G UE-to-network relay according to some example embodiments is shown.

[0159] Some example embodiments relate to the handling of Internet Protocol version 4. The relay UE 104 assigns an IP@ to the remote UE 102; the relay UE 104 performs network address and port translation (NAPT) between PC5 and Uu. For downlink (DL) traffic, it uses ports above the IP to determine the PC5 address and link to be used (remote UE 102). The relay UE 104 does not know whether it is relaying the user plane (UP) or the control plane (CP) for the remote UE 102.

[0160] Some example embodiments relate to the handling of Internet Protocol version 6. The relay UE 104 provides an IP prefix to the remote UE 102; the relay UE 104 can use prefix delegation (PD) to obtain a prefix to assign to the remote UE(s) 102. The relay UE 104 acts as a requesting router.

[0161] According to some example embodiments, the core network 116 to which the relay UE 104 is registered and the core network 118 to which the remote UE 102 is registered correspond to the same public land mobile network (PLMN).

[0162] According to some example embodiments, the core network 116 to which the relay UE 104 is registered and the core network 118 to which the remote UE 102 is registered correspond to different PLMNs.

[0163] According to some example embodiments, the RAN transparency of the RAN 106 for the remote UE ensures the confidentiality of the data traffic of the remote UE 102 without being eavesdropped by the relay UE 104, and / or the possibility of retaining the IP address for the remote UE 102 when the remote UE 102 moves between (i) PC5 access via the relay UE 104 and (ii) local direct Uu access to the 5G system (5GS) without a relay.

[0164] According to some example embodiments, the operation is transparent to the NG RAN 106. The NG RAN (gNB) 106 and the UPF 108 of the relay UE 104 are unaware of the relay operation of the remote UE 102.

[0165] Figure 7 A representation of the connection of the remote UE 102 via the relay UE 104 according to some example embodiments is shown.

[0166] Operation 0: Supply the relay UE 104 and the remote UE 102 for UE-to-NW relay, including supply for baseline PC5 usage and relay operation. The information supplied may include at least the information of the N3IWF, the policy for using the N3IWF, security parameters, etc.

[0167] Operation 1: The relay UE 104 registers with the 5G core network, which may follow the registration process specified in TS23.502.

[0168] Operation 2: The remote UE 102 discovers and selects the relay UE 104, and establishes a connection for one-to-one ProSe direct communication.

[0169] Operation 3: The remote UE 102 requests ProSe 5G UE-to-network relay operation. A relay authorization process may be performed.

[0170] Operation 4: If the 5G relay UE 104 does not have a PDU session that can support the requirements for the connection between the PC5 and the remote UE 102, including appropriate single network slice selection assistance information (S-NSSAI), data network name (DNN), and quality of service (QoS) parameters, the relay UE 104 will initiate a PDU session establishment to relay the traffic of the remote UE 102. The trigger for establishing this dedicated PDU session may be the first PC5 establishment request from the remote UE 102. The PDU session release criterion may be the release of the last PC5 of the remote UE 102.

[0171] Operation 5: Allocate an IPv6 prefix and / or allocate an IPv4 address to the remote UE. After this step, uplink and downlink data relaying can start. The remote UE 102 obtains a local IP address from the relay UE 104 according to the L3 procedure, where the relay UE 104 acts as a Dynamic Host Configuration Protocol (DHCP) server (or a Stateless Address Autoconfiguration (SLAAC) router or a prefix delegation router for IPv6) and NAPT. The relay UE 104 can implement NAPT between PC5 and Uu. For DL services, the relay UE 104 uses Transmission Control Protocol / User Datagram Protocol (TCP / UDP) ports to determine the PC5 address and link (remote UE 102) to be used. The relay UE 104 holds a mapping table between the local IP address and the PC5 link, as the relay UE 104 can act as a relay for multiple remote UEs 102.

[0172] From here on, the remote UE signaling procedure for its N3IWF runs on top of the PDU session established by the relay UE 104 in Operation 4 and uses the IP address information negotiated in Operation 5.

[0173] Operation 6: The remote UE 102 determines whether it needs the service of the N3IWF. This decision can depend on the UE implementation, or can be controlled by local policies (local policies can consider application-level encryption mechanisms and application-level IP mobility requirements), and / or by operator policies configured in the remote UE and / or by information or indications received from the relay UE 104.

[0174] Operation 7a: The remote UE 102 discovers the N3IWF using DNS lookup or using the configured N3IWF information.

[0175] Operation 7b: The remote UE 102 connects to the N3IWF selected in Operation 7a for Internet Key Exchange (IKE) establishment.

[0176] Operation 7c: The remote UE 102 registers with the core network (5GC) via the selected N3IWF. The N3IWK regards the access of this remote UE as N3GPP access. Therefore, the remote UE is authenticated via its own credentials.

[0177] Operation 8: The remote UE 102 establishes a data connection via the registered N3IWF access. The remote UE 102 may establish one or more PDU sessions or move an existing PDU session as follows. The remote UE 102 may establish one or more new PDU sessions. Based on the mobility of the PDU sessions used by the remote UE 102 before using the relay, the remote UE 102 may follow the PDU session mobility procedure. The remote UE registers via the N3IWF and establishes a PDU session. According to some example embodiments, IPsec is used for both the NAS and UP services of the remote UE 102, and both the NAS and UP services of the remote UE 102 are hidden from the relay UE 104.

[0178] The keep-alive IKE between the remote UE 102 and the N3IWF 122 may be used to detect possible path failures.

[0179] When the remote UE 102 and the N3IWF 122 support the IKEv2 Mobility and Multihoming Protocol (MOBIKE), the mobility of the remote UE 102 between different relay UEs (s) may be supported. This is negotiated between the remote UE 102 and the N3IWF 122.

[0180] Figure 8 An example of a control device 900 at any entity (such as AMF entities 110, 114 and UPF entities 108, 112) for the RAN 106 and the core network 116, 118 is illustrated. The control device may at least include at least one random access memory (RAM) 911a, at least one read-only memory (ROM) 911b, at least one processor 912, 913 and an input / output interface 914. The at least one processor 912, 913 may be coupled to the RAM 911a and the ROM 911b. The at least one processor 912, 913 may be configured to execute appropriate software code 915. For example, the software code 915 may allow the execution of one or more steps to perform one or more of the above operations. The software code 915 may be stored in the ROM 911b. The control device 900 at one of the above entities may be interconnected with another control device 900 at one or more of the above entities.

[0181] Figure 9FIG. illustrates an example of a user equipment or terminal 1000, such as the user equipment described previously. The terminal 1000 can be provided by any device capable of sending and receiving radio signals. Non-limiting examples include a mobile station (MS) or mobile device, such as a mobile phone or a so-called "smartphone", a computer equipped with a radio interface card or other radio interface facilities (e.g., a USB dongle), a personal digital assistant (PDA) or a tablet computer equipped with wireless communication capabilities, a machine-type communication (MTC) device, an Internet of Things (IoT) type communication device, or any combination of these devices or similar devices. For example, the terminal 1000 can provide data communication for carrying communications. The communication can be one or more of voice, email, text message, multimedia, data, machine data, etc.

[0182] The terminal 1000 can receive signals via an appropriate device for reception over the air or radio interface 1007, and can also transmit signals via an appropriate device for transmitting radio signals. In Figure 10 FIG., the module 1006 schematically designates transceiver means. For example, the transceiver means 1006 can be provided by radio components and associated antenna arrangements. The antenna arrangement can be disposed inside or outside the mobile device.

[0183] The terminal 1000 can be provided with at least one processor 1001, at least one memory ROM 1002a, at least one RAM 1002b, and other possible components 1003 for software and hardware assisted execution of the tasks it is designed to perform, including controlling access to and communication with access systems and other communication devices. The at least one processor 1001 is coupled to the RAM 1011a and the ROM 1011b. The at least one processor 1001 can be configured to execute appropriate software code 1008. For example, the software code 1008 can allow execution of one or more aspects of the present disclosure. The software code 1008 can be stored in the ROM1011b.

[0184] The processor, storage, and other associated control means can be provided on an appropriate circuit board and / or chipset. This feature is denoted by the reference numeral 1004. The device can optionally have a user interface, such as a keyboard 1005, a touchscreen or a keyboard, a combination thereof, etc. Optionally, one or more of a display, a speaker, and a microphone are provided, depending on the type of the device.

[0185] Figure 10A schematic diagram of non-volatile storage media 1100a (e.g., a computer compact disc (CD) or a digital versatile disc (DVD)) and 1100b (e.g., a universal serial bus (USB) memory stick) is shown. The storage media stores instructions and / or parameters 1102, which, when executed by a processor, allow the processor to execute one or more steps of the above-described method.

[0186] It should be noted that embodiments of the present invention can be implemented as a circuit system in software, hardware, application logic, or a combination of software, hardware, and application logic. In an example embodiment, the application logic, software, or instruction set is maintained on any of a variety of conventional computer-readable media. In this document, a "computer-readable medium" can be any medium or means that can contain, store, transmit, propagate, or transport instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer, a smart phone, or a user device.

[0187] As used in this application, the term "circuit system" refers to all of the following: (a) only hardware circuit implementations (such as those in only analog and / or digital circuit systems), and (b) combinations of circuits and software (and / or firmware), such as, as applicable: (i) combinations of (one or more) processors, or (ii) (one or more) processors / software (including (one or more) digital signal processors), software, and portions of (one or more) memories that work together to cause a device such as a mobile phone or a server to perform various functions), and (c) circuits, such as (one or more) microprocessors or portions of (one or more) microprocessors, that require software or firmware to operate, even if the software or firmware is not physically present. This definition of "circuit system" applies to all uses of the term in this application, including in any claims. As a further example, as used in this application, the term "circuit system" will also cover implementations that include only one processor (or more processors) or a portion of a processor and its (or their) attendant software and / or firmware. The term "circuit system" will also cover, for example, if applicable to a particular claim element, the baseband integrated circuit or the application processor integrated circuit of a mobile phone, or a similar integrated circuit in a server, a cellular network device, or other network device.

[0188] The features, advantages, and characteristics of the present invention can be combined in any suitable manner in one or more embodiments. Those skilled in the relevant technical field will recognize that the present invention can be practiced without one or more specific features or advantages of a particular embodiment. In other instances, additional features and advantages can be identified in certain embodiments that are not present in all embodiments of the present invention. Those of ordinary skill in the art will readily understand that the above-described invention can be implemented by steps in a different order and / or hardware elements different from the disclosed configurations. Accordingly, although the present invention has been described based on these preferred embodiments, certain modifications, variations, and alternative structures will be apparent to those skilled in the art while still remaining within the spirit and scope of the present invention.

Claims

1. A device for communication, comprising: At least one processor; And At least one memory, including computer program code, the at least one memory and the computer program code being configured to, together with the at least one processor, cause the device to perform: Prepare a message at a first user equipment and transmit the message via a radio interface between the first user equipment and a second user equipment, wherein the message at least includes content addressed to a core network for the first user equipment, and wherein the core network for the first user equipment is independent of the core network for the second user equipment, and the message further includes information for selecting an access and mobility management function entity for the first user equipment by the core network for the second user equipment.

2. The device according to claim 1, wherein the message at least includes: At least content that is transparent to the core network for the second user equipment.

3. The device according to claim 1 or 2, wherein the message at least includes a layer 2 message, and the content addressed to the core network for the first user equipment at least includes layer 3 content.

4. A device for communication, comprising: At least one processor; And At least one memory, including computer program code, the at least one memory and the computer program code being configured to, together with the at least one processor, cause the device to perform: Receive a message at a core network for a first user equipment, at least via a radio interface between the first user equipment and a second user equipment, wherein the message includes information for selecting an access and mobility management function entity for the first user equipment by the core network for the second user equipment; and Send at least some of the content of the message to the core network for the second user equipment.

5. The apparatus according to claim 4, wherein the content sent to the core network for the second user equipment at least includes: At least content that is transparent to the core network for the first user equipment.

6. The device according to claim 4 or 5, wherein the content sent to the core network for the second user equipment at least includes layer 3 content.

7. The device according to claim 4 or 5, wherein the content sent to the core network for the second user equipment includes an Ethernet packet data unit.

8. The device according to claim 4, wherein the at least one memory and the computer program code are configured to, together with the at least one processor, cause the device to perform: Select a mobility management function entity for the second user equipment, wherein the mobility management function for the second user equipment is independent of the mobility management function for the first user equipment.

9. A device for communication, comprising: At least one processor; And At least one memory, including computer program code, the at least one memory and the computer program code being configured to, together with the at least one processor, cause the device to perform: At a core network for a first user equipment, receive a message from a core network for a second user equipment, where the message includes information for selecting an access and mobility management function entity for the first user equipment by the core network for the second user equipment, and where the second user equipment is connected to the core network for the first user equipment at least via a radio interface between the first user equipment and the second user equipment; and Forward the message to a radio access network for the first user equipment.

10. The apparatus according to claim 9, wherein the message includes an Ethernet packet data unit.

11. A communication method, comprising: Prepare a message at a first user equipment, and Transmit the message via a radio interface between the first user equipment and a second user equipment, where the message at least includes content addressed to a core network for the first user equipment, and where the core network for the first user equipment is independent of the core network for the second user equipment, and the message further includes information for selecting an access and mobility management function entity for the first user equipment by the core network for the second user equipment.

12. A communication method, comprising: At a core network for a first user equipment, receive a message at least via a radio interface between the first user equipment and a second user equipment, where the message includes information for selecting an access and mobility management function entity for the first user equipment by the core network for the second user equipment; and Send at least some of the content of the message to the core network for the second user equipment.

13. A communication method, comprising: At a core network for a first user equipment, receive a message from a core network for a second user equipment, where the message includes information for selecting an access and mobility management function entity for the first user equipment by the core network for the second user equipment, and where the second user equipment is connected to the core network for the first user equipment at least via a radio interface between the first user equipment and the second user equipment; and Forward the message to a radio access network for the first user equipment.

14. A computer-readable medium, comprising program instructions stored on the computer-readable medium for performing: Prepare a message at a first user equipment, and Transmit the message via a radio interface between the first user equipment and a second user equipment, where the message at least includes content addressed to a core network for the first user equipment, and where the core network for the first user equipment is independent of the core network for the second user equipment, and the message further includes information for selecting an access and mobility management function entity for the first user equipment by the core network for the second user equipment.

15. A computer-readable medium, comprising program instructions stored on the computer-readable medium for performing: At a core network for a first user equipment, receiving a message at least via a radio interface between the first user equipment and a second user equipment, wherein the message includes information for selecting an access and mobility management function entity for the first user equipment by a core network for the second user equipment; and Sending at least some of the content in the message to the core network for the second user equipment.

16. A computer-readable medium, including program instructions stored on the computer-readable medium for performing: At a core network for a first user equipment, receiving a message from a core network for a second user equipment, wherein the message includes information for selecting an access and mobility management function entity for the first user equipment by a core network for the second user equipment, wherein the second user equipment is connected to the core network for the first user equipment at least via a radio interface between the first user equipment and the second user equipment; and Forwarding the message to a radio access network for the first user equipment.

17. A device for communication, including: Components for preparing a message at a first user equipment, and Components for transmitting the message via a radio interface between the first user equipment and a second user equipment, wherein the message at least includes content addressed to a core network for the first user equipment, and wherein the core network for the first user equipment is independent of the core network for the second user equipment, and the message further includes information for selecting an access and mobility management function entity for the first user equipment by a core network for the second user equipment.

18. A device for communication, including: Components for receiving a message at a core network for a first user equipment at least via a radio interface between the first user equipment and a second user equipment, wherein the message includes information for selecting an access and mobility management function entity for the first user equipment by a core network for the second user equipment; And Components for sending at least some of the content in the message to the core network for the second user equipment.

19. A device for communication, including: Components for receiving a message at a core network for a first user equipment from a core network for a second user equipment, wherein the message includes information for selecting an access and mobility management function entity for the first user equipment by a core network for the second user equipment, wherein the second user equipment is connected to the core network for the first user equipment at least via a radio interface between the first user equipment and the second user equipment; And Components for forwarding the message to a radio access network for the first user equipment.

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