Initial access of remote devices via relay

Abstract

Example embodiments of the present disclosure relate to initial access of a remote device via a relay. A first device transmits a connection request to a second device, the connection request being used to establish a control plane connection between the first device and a third device, wherein the connection request includes information of the first device used to establish a control plane connection between the first device and the third device, so that the second device can transmit the control plane connection request to the third device based on the information. The first device receives from the second device a radio resource control message transmitted by a fourth device in response to a control plane connection acceptance message from the third device. Through this solution, secure, flexible and efficient initial access of the first device is provided.

Description

Technical Field

[0001] Embodiments of the present disclosure relate generally to the field of telecommunications, and more particularly to methods, devices, apparatuses, and computer-readable storage media for initial access of a remote device via a relay. Background Art

[0002] With the development of communication systems, more and more technologies have been proposed. In the current wireless communication system, in order to allow a terminal device to communicate with a fifth generation core (5GC) network device (such as an access and mobility management function (AMF), etc.), a radio resource control (RRC) connection first needs to be established between the terminal device and a radio access network (RAN) node, and then after successful authentication and authorization of the terminal device, a control plane (CP) connection with a non-access stratum (NAS) level can be connected.

[0003] In current communication systems, a side link (SL) can be established between two devices (such as terminal devices) to achieve direct communication or relay communication. Therefore, a remote terminal device can access the service via a relay terminal device. In addition, work items are being carried out in the third generation partnership project (3GPP) for a relay solution based on SL. Effective initial access of a remote terminal device is desired. Summary of the invention

[0004] In general, example embodiments of the present disclosure provide a solution for initial access of a remote device via a relay. Embodiments that do not fall within the scope of the claims, if any, are to be construed as examples useful for understanding the various embodiments of the present disclosure.

[0005] In a first aspect, a first device is provided. The first device includes at least one processor; and at least one memory, including computer program code; wherein the at least one memory and the computer program code are configured to, together with the at least one processor, enable the first device to transmit a connection request to a second device. The connection request is used to establish a CP connection between the first device and a third device. The connection request includes information of the first device used to establish a CP connection between the first device and the third device, so that the second device transmits a CP connection request to the third device based on the information. The first device is also caused to receive an RRC message from the second device, the RRC message being used to establish an RRC connection between the first device and a fourth device. The RRC message is transmitted by the fourth device after receiving a CP connection acceptance message from the third device.

[0006] In a second aspect, a second device is provided. The second device includes at least one processor; and at least one memory, including computer program code; wherein the at least one memory and the computer program code are configured to, together with the at least one processor, enable the second device to receive a connection request from a first device, the connection request being used to establish a CP connection between the first device and a third device. The connection request includes information of the first device for establishing a CP connection between the first device and the third device. The second device is also caused to transmit a CP connection request to the third device based on the information. The second device is also caused to receive an RRC message from a fourth device, the RRC message being used to establish an RRC connection between the first device and the fourth device. The RRC message is transmitted after receiving a CP connection acceptance message from the third device. The second device is also caused to transmit an RRC message to the first device.

[0007] In a third aspect, a third device is provided. The third device includes at least one processor; and at least one memory, including computer program code; wherein the at least one memory and the computer program code are configured to, together with the at least one processor, enable the third device to receive a CP connection request from a second device. The CP connection request is generated based on information of the first device for establishing a CP connection between the first device and the third device. The third device is also caused to transmit a CP connection acceptance message to the fourth device, so that the fourth device transmits an RRC message to the second device, the RRC message being used to establish an RRC connection between the first device and the fourth device.

[0008] In a fourth aspect, a fourth device is provided. The fourth device includes at least one processor; and at least one memory, including computer program code; wherein the at least one memory and the computer program code are configured to, together with the at least one processor, enable the fourth device to receive a CP connection acceptance message from a third device. The CP connection acceptance message is transmitted after receiving a CP connection request from a second device, the CP connection request being used to establish a CP connection between the first device and the third device. The third device is also caused to transmit an RRC message to the second device, the RRC message being used to establish an RRC connection between the first device and the fourth device.

[0009] In a fifth aspect, a method is provided. The method includes transmitting a connection request at a first device to a second device, the connection request being used to establish a CP connection between the first device and the second device. The connection request includes information of the first device for establishing a CP connection between the first device and a third device, so that the second device transmits a CP connection request to the third device based on the information. The method also includes receiving an RRC message from the second device, the RRC message being used to establish an RRC connection between the first device and a fourth device. The RRC message is transmitted by the fourth device after receiving a CP connection acceptance message from the third device.

[0010] In a sixth aspect, a method is provided. The method includes receiving a connection request from a first device at a second device, the connection request being used to establish a CP connection between the first device and a third device. The connection request includes information of the first device used to establish a CP connection between the first device and the third device. The method also includes transmitting the CP connection request to the third device based on the information. The method also includes receiving an RRC message from a fourth device, the RRC message being used to establish an RRC connection between the first device and the fourth device. The RRC message is transmitted after receiving a CP connection acceptance message from the third device. The method also includes transmitting an RRC message to the first device.

[0011] In a seventh aspect, a method is provided. The method includes receiving, at a third device, a CP connection request from a second device from a second device. The CP connection request is generated based on information of the first device for establishing a CP connection between the first device and the third device. The method includes transmitting a CP connection accept message to a fourth device, so that the fourth device transmits an RRC message to the second device, the RRC message being used to establish an RRC connection between the first device and the fourth device.

[0012] In an eighth aspect, a method is provided. The method includes receiving, at a fourth device, a CP connection accept message from a third device from a third device. The CP connection accept message is sent after receiving a CP connection request from a second device, the CP connection request being used to establish a CP connection between a first device and a third device. The method includes transmitting an RRC message to the second device, the RRC message being used to establish an RRC connection between the first device and the fourth device.

[0013] In a ninth aspect, a first device is provided. The first device includes a component for transmitting a connection request to a second device, the connection request being used to establish a CP connection between the first device and a third device. The connection request includes information of the first device for establishing a CP connection between the first device and the third device, so that the second device can transmit the CP connection request to the third device based on the information. The first device also includes a component for receiving an RRC message from a second device, the RRC message being used to establish an RRC connection between the first device and a fourth device. The RRC message is transmitted by the fourth device after receiving a CP connection acceptance message from the third device.

[0014] In a tenth aspect, a second device is provided. The second device includes a component for receiving a connection request from a first device, the connection request being used to establish a control plane connection between the first device and the second device. The connection request includes information of the first device for establishing a CP connection between the first device and a third device. The second device also includes a component for transmitting a CP connection request to the third device based on the information. The second device also includes a component for receiving an RRC message from a fourth device, the RRC message being used to establish an RRC connection between the first device and the fourth device. The RRC message is transmitted after receiving a CP connection acceptance message from the third device. The second device also includes a component for transmitting an RRC message to the first device.

[0015] In an eleventh aspect, a third device is provided. The third device includes a component for receiving a CP connection request from a second device. The CP connection request is generated based on information of a first device for establishing a CP connection between a first device and a third device. The third device also includes a component for transmitting a CP connection acceptance message to a fourth device, so that the fourth device transmits an RRC message to the second device, and the RRC message is used to establish an RRC connection between the first device and the fourth device.

[0016] In a twelfth aspect, a fourth device is provided. The fourth device includes a component for receiving a CP connection acceptance message from a third device. The CP connection acceptance message is transmitted after receiving a CP connection request from a second device, the CP connection request being used to establish a CP connection between the first device and the third device. The fourth device also includes a component for transmitting an RRC message to the second device, the RRC message being used to establish an RRC connection between the first device and the fourth device.

[0017] In a thirteenth aspect, a computer-readable medium is provided, wherein the computer-readable medium comprises program instructions, and the program instructions are used to cause an apparatus to at least execute the method according to the fifth aspect.

[0018] In a fourteenth aspect, a computer-readable medium is provided, wherein the computer-readable medium comprises program instructions, and the program instructions are used to cause an apparatus to at least execute the method according to the sixth aspect.

[0019] In a fifteenth aspect, a computer-readable medium is provided, wherein the computer-readable medium comprises program instructions, and the program instructions are used to cause an apparatus to at least execute the method according to the seventh aspect.

[0020] In a sixteenth aspect, a computer-readable medium is provided, wherein the computer-readable medium comprises program instructions, and the program instructions are used to cause an apparatus to at least execute the method according to the eighth aspect.

[0021] It should be understood that the invention summary is not intended to identify the key or essential features of the embodiments of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will become readily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Some example embodiments will now be described with reference to the accompanying drawings, in which:

[0023] Figure 1 illustrates an example communication environment in which example embodiments of the present disclosure may be implemented;

[0024] Figure 2 The figure illustrates a conventional signaling flow for initial access of a terminal device without a relay;

[0025] Figure 3 The figure shows the conventional signaling process for establishing a PC5 direct link between a remote terminal device and a relay terminal;

[0026] Figure 4 A conventional signaling flow for initial access of a remote terminal device via a relay terminal device is illustrated;

[0027] Figure 5 illustrates a signaling flow for an initial access procedure according to some example embodiments of the present disclosure;

[0028] Figure 6 illustrates an example CP protocol stack for L2 relay according to some example embodiments of the present disclosure;

[0029] Figure 7 illustrates yet another example CP protocol stack for L2 relay according to some example embodiments of the present disclosure;

[0030] Figure 8 illustrates an example CP protocol stack for L3 relay according to some example embodiments of the present disclosure;

[0031] Fig. 9 illustrates a flow chart of a method implemented at a first device according to some other example embodiments of the present disclosure;

[0032] Fig.10 illustrates a flow chart of a method implemented at a second device according to some other example embodiments of the present disclosure;

[0033] Fig.11 illustrates a flow chart of a method implemented at a third device according to some other example embodiments of the present disclosure;

[0034] Fig.12 illustrates a flow chart of a method implemented at a fourth device according to some other example embodiments of the present disclosure;

[0035] Fig.13 illustrates a simplified block diagram of an apparatus suitable for implementing an example embodiment of the present disclosure; and

[0036] Fig.14 A block diagram of an example computer-readable medium according to some example embodiments of the present disclosure is illustrated.

[0037] Throughout the drawings, the same or similar reference numerals refer to the same or similar elements. DETAILED DESCRIPTION

[0038] The principle of the present disclosure will now be described with reference to some example embodiments. It should be understood that these embodiments are described only to illustrate and help those skilled in the art to understand and implement the present disclosure, and do not imply any limitation on the scope of the present disclosure. The disclosure described herein can be implemented in various ways except for the way described below.

[0039] In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0040] References in this disclosure to "an embodiment," "an embodiment," "an example embodiment," etc., indicate that the described embodiment may include a particular feature, structure, or characteristic, but not every embodiment necessarily includes the particular feature, structure, or characteristic. Furthermore, these phrases do not necessarily refer to the same embodiment. Furthermore, when a particular feature, structure, or characteristic is described in conjunction with an embodiment, it is considered within the knowledge of those skilled in the art to affect such feature, structure, or characteristic in conjunction with other embodiments, whether or not explicitly described.

[0041] It should be understood that although the terms "first" and "second" etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element without departing from the scope of the example embodiments. As used herein, the term "and / or" includes any and all combinations of one or more of the listed terms.

[0042] The terms used herein are for the purpose of describing specific embodiments only and are not intended to limit the exemplary embodiments. As used herein, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "include", "comprises", "comprising", "having", "having" and / or "containing", when used herein, specify the presence of the features, elements and / or components, etc., but do not exclude the presence or addition of one or more other features, elements, components and / or combinations thereof.

[0043] As used in this application, the term "circuitry" may refer to one or more or all of the following:

[0044] (a) pure hardware circuit implementation (such as implementation in analog and / or digital circuitry only) and

[0045] (b) a combination of hardware circuitry and software such as (where applicable):

[0046] (i) a combination of analog and / or digital hardware circuits and software / firmware and

[0047] (ii) any portion of hardware processor(s) with software (including digital signal processor(s), software and memory(s) that work together to enable a device (such as a mobile phone or server) to perform various functions) and

[0048] (c) Hardware circuits and / or processor(s), such as microprocessor(s) or portions of microprocessor(s), require software (e.g., firmware) to operate, but the software may not be present when the software is not required for operation.

[0049] This definition of circuitry 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 circuitry also covers an implementation of only a hardware circuit or processor (or multiple processors) or a portion of a hardware circuit or processor and its (or their) accompanying software and / or firmware. For example, if applicable to a particular claim element, the term circuitry also covers a baseband integrated circuit or processor integrated circuit for a mobile device, or a similar integrated circuit in a server, cellular base station, or other computing or fourth device.

[0050] As used herein, the term "communication network" refers to a network that complies with any suitable communication standard, such as New Radio (NR), Long Term Evolution (LTE), LTE-Advanced (LTE-A), Wideband Code Division Multiple Access (WCDMA), High Speed ​​Packet Access (HSPA), Narrowband Internet of Things (NB-IoT), etc. In addition, the communication between the first device and the fourth device in the communication network can be performed according to any suitable generation of communication protocols, including but not limited to the first generation (1G), second generation (2G), 2.5G, 2.75G, third generation (3G), fourth generation (4G), 4.5G, future fifth generation (5G) communication protocols, and / or any other protocol currently known or to be developed in the future. The embodiments of the present disclosure can be applied in various communication systems. In view of the rapid development of communication, there will certainly be communication technologies and systems of future types that can embody the present disclosure. It should not be considered that the scope of the present disclosure is limited to the above-mentioned system.

[0051] The term "core device" refers to any device or entity that provides access and mobility management functions, session management function (SMF), user plane function (UPF), etc. By way of example and not limitation, the core device may be an AMF, SMF, UPF, etc. In other embodiments, the core device may be any other suitable device or entity.

[0052] As used herein, the term "network device" refers to a node in a communication network, via which a terminal device accesses the network and receives services from it. A network device may refer to a base station (BS) or an access point (AP), such as a NodeB (NodeB or NB), an evolved NodeB (eNodeB or eNB), a NR NB (also known as a gNB), a remote radio unit (RRU), a radio head (RH), a remote radio head (RRH), a relay, an integrated access and backhaul (IAB) node, a low power node (such as a femto, a micro), a non-terrestrial network (NTN) or a non-terrestrial fourth device (such as a satellite fourth device), a low earth orbit (LEO) satellite and a geosynchronous earth orbit (GEO) satellite, an aircraft fourth device, etc., depending on the terminology and technology applied.

[0053] The term "terminal device" refers to any terminal device capable of wireless communication. By way of example and not limitation, a terminal device may also be referred to as a communication device, a user equipment (UE), a subscriber station (SS), a portable subscriber station, a mobile station (MS), or an access terminal (AT). The terminal device may include, but is not limited to, a mobile phone, a cellular phone, a smart phone, a voice over IP (VoIP) phone, a wireless local loop phone, a tablet computer, a wearable terminal device, a personal digital assistant (PDA), a portable computer, a desktop computer, an image capture terminal device (such as a digital camera), a game terminal device, a music storage and playback device, a vehicle-mounted wireless terminal device, a wireless endpoint, a mobile station, a notebook Computer embedded equipment (LEE), laptop mounted equipment (LME), USB dongle, smart device, wireless client equipment (CPE), Internet of Things (IoT) device, watch or other wearable device, head mounted display (HMD), vehicle, drone, medical equipment and applications (e.g., remote surgery), industrial equipment and applications (e.g., robots and / or other wireless devices operating in industrial and / or automated process chain environments), consumer electronic devices, devices operating on commercial and / or industrial wireless networks, etc. In the following description, the terms "terminal device", "communication device", "terminal", "user equipment" and "UE" can be used interchangeably.

[0054] The term "remote terminal device" refers to a terminal device that communicates with a network device and a core device via another device (i.e., a relay terminal device) outside the coverage of the network device or the core device, or due to other reasons, such as being blocked by obstacles, lacking the ability to communicate with the network device and the core device, etc.

[0055] The term "relay terminal device" refers to a terminal device that acts as a relay for another device (eg, a remote terminal device) to enable the other device to communicate with a network device and / or a core device.

[0056] Although the functions described herein may be performed in various example embodiments, in other example embodiments, the functions may be performed in fixed and / or wireless network nodes, and the functions may be performed in user equipment devices (such as cell phones or tablet computers or laptop computers or desktop computers or mobile IOT devices or fixed IOT devices). For example, the user equipment device may be appropriately equipped with corresponding capabilities as described in conjunction with (multiple) fixed and / or wireless network nodes. The user equipment device may be a user device and / or a control device, such as a chipset or a processor, configured to control the user equipment when installed therein. Examples of such functions include boot server functions and / or home subscriber servers, which may be implemented in the user equipment device by providing software to the user equipment device, which, from the perspective of these functions / nodes, is configured to enable the user equipment device to perform.

[0057] It should be understood that the term "side link (SL)" refers to a direct communication link and / or discovery link between two or more terminal devices, the term "PC5" refers to an interface for implementing communication and / or discovery between two or more terminal devices, and the term "PC5 direct link" refers to a link established between two or more terminal devices through a PC5 interface. The terms "side link" and "PC5 direct link" described herein are equivalent to each other.

[0058] Figure 1 An example communication environment 100 is shown in which example embodiments of the present disclosure may be implemented. In the communication environment 100, a first device 110 may communicate with a second device 120 via a physical communication channel or link, the second device 120 may communicate with a third device 130 and a fourth device 140 via a physical communication channel or link, and the third device 130 may communicate with the fourth device 140 via a physical communication channel or link. Figure 1In the example of FIG. 1 , the first device 110 and the second device are illustrated as terminal devices, wherein the first device 110 is a remote terminal device, and the second device 120 is a relay terminal device. The third device 130 is illustrated as a core device serving the terminal device. The fourth device 140 is illustrated as a network device serving the terminal device. Specifically, the first device 110 communicates with the third device 130 and the fourth device 140 via the second device 120. The second device 120 communicates with the third device 130 via the fourth device 140.

[0059] It should be understood that the number of first devices, second devices, third devices, and fourth devices is only for illustrative purposes and does not imply any limitation. Communication environment 100 may include any suitable number of first devices, second devices, third devices, and fourth devices suitable for implementing embodiments of the present disclosure.

[0060] Conventionally, in order to access services provided by a communication system, a terminal device needs to perform a registration process. Figure 2 It is a traditional signaling process 200 for initial access in which a terminal device directly accesses a communication system without relaying. In the traditional initial access process, the terminal device initiates a random access channel (RACH) process to obtain uplink synchronization with a network device, and then requests to establish an RRC connection with the network device. After the RRC connection between the terminal device and the network device is established, a registration or service request can be sent to the core device via the established RRC connection to establish a CP connection, such as a non-access stratum (NAS) connection between the terminal device and the core device. However, due to the relay communication between the remote terminal device and the network device / core device, the initial access process cannot be reused by the remote terminal device, especially for the connection establishment between the terminal device and the network device using RACH-related processes. Instead of initiating a RACH process for establishing an RRC connection between the terminal device and the network device, the remote terminal device needs to first establish a PC5 direct link with the relay terminal device, such as. Figure 3 shown.

[0061] Figure 3 The conventional signaling process 300 of establishing a PC5 direct link between a remote terminal device and a relay terminal is shown. However, the establishment process only establishes a connection between the remote terminal device and the relay terminal device. The connection between the remote terminal device and the network device and / or the core device still needs to be established so that the terminal device can communicate with the network device and / or the core device via the relay terminal device.

[0062] Figure 4 The conventional signaling flow 400 for initial access of a remote terminal device via a relay terminal device is shown. Figure 4As shown in FIG. 5 , the relay terminal device is activated, and the remote terminal device and the relay terminal device are connected to each other via the PC5 link. Figure 4 As shown, the remote terminal device first needs to establish an RRC connection with the network device by exchanging RRC signaling with the network device via the relay terminal device and then sending a registration or service request to the core device for further processing (e.g., authentication). The NAS connection of the remote terminal device can be established after further processing (e.g., successful authentication).

[0063] However, according to the traditional signaling process, the RRC connection between the remote terminal device and the network device must be established first, and then the CP (e.g., NAS) connection between the remote terminal device and the core device is established after successful authentication. In the case of unsuccessful authentication, the NAS connection will not be established and the pre-established RRC connection must be released. Therefore, in the case of authentication failure, it will cause unnecessary signaling and processing overhead for RRC connection establishment. In addition, since all signaling between the remote terminal device and the network device and / or the core network device is relayed via the relay terminal device, the signaling overhead exchanged between the network elements is complex, which causes undesirable delays.

[0064] Therefore, there is a need for secure, flexible and efficient initial access of remote terminal devices via relay terminal devices.

[0065] According to some example embodiments of the present disclosure, a solution for initial access of a remote device (such as a remote terminal device) via a relay device (such as a relay terminal device) is provided. During the initial access process, the remote terminal device transmits a connection request to the relay terminal device, and the connection request is used to establish a CP connection between the remote terminal device and the core device. The connection request includes information of the remote terminal device for establishing a CP connection between the remote terminal device and the core device. Using the above information, the relay terminal device can transmit a registration request or a service request to the remote terminal device, and the registration request or the service request is used to trigger the establishment of a CP connection between the remote terminal device and the core device. If the core device determines to accept the registration request or the service request after the authentication process of the remote terminal device, the core device can send a message to trigger the network device to initiate an RRC connection between the remote terminal device and the network device. In this way, the RRC connection can be triggered by the network side after successful authentication and the core device accepts the registration or service request. Therefore, unnecessary RRC connection establishment caused by unsuccessful authentication can be avoided. In addition, through the above-mentioned improved process, the delay of initial access is shortened and the signaling overhead is reduced.

[0066] Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Figure 5A flowchart 500 of a method according to some other example embodiments of the present disclosure is illustrated. The flowchart 500 can be implemented on any suitable device. For illustrative purposes only, the flowchart 500 is described as being implemented at a first device 110 (such as a remote terminal device), a second device 120 (such as a relay terminal device), a third device 130 (such as a core device), and a fourth device 140 (such as a network device).

[0067] It should be understood that Figure 5 The number of first devices 110, second devices 120, third devices 130, and fourth devices 140 shown in FIG. 5 is given for illustrative purposes and does not imply any limitation. Flowchart 500 may include any suitable number of first devices, second devices 120, third devices 130, and fourth devices 140.

[0068] The first device 110 first transmits 502 a connection request to the second device 120 via the PC5 interface, the connection request being used to establish a CP connection between the first device 110 and the third device 130. In some example embodiments, the connection request includes information of the first device 110 for establishing a CP connection between the first device 110 and the third device 130.

[0069] In some example embodiments, the information included in the connection request may be all or part of an initiating NAS message that may be transmitted as an information element (IE) in the connection request. In this case, the connection request on PC5 may be implemented as an extension of the current direct communication request. When the first device 110 transmits a direct communication request, the first device 110 may optionally include all or part of an IE in a conventional initiating NAS message (such as a registration request, a service request, etc.) in the direct communication request information. It should be noted that the above messages are for illustrative purposes only and do not imply any limitation. In other example embodiments, any suitable control message may be used.

[0070] Alternatively or additionally, the information included in the connection request may include information such as an indication of the type of NAS connection to be established (such as the type of the requested NAS procedure, etc.), an identification (ID) of the first device 110 (such as a UE ID for a registration request or a ProSe ID for a PC5 interface, etc.), and information of a network slice (such as network slice selection assistance information (NSSAI), etc.). In other words, the first device 110 may indicate only necessary information of the first device 110 for establishing a CP connection between the first device 110 and the third device 130.

[0071] In addition, in some example embodiments, mutual authentication between the first device 110 and the second device 120 involving the third device 130 may be performed as follows: Figure 3During the mutual authentication process, the third device 130 may provide the second device 120 with auxiliary information about the first device 110. The auxiliary information will assist the second device 120 in later transmitting a CP connection request to the first device 110. For example, the first device 110 provides the second device 120 with the authentication information of the first device 110 so that the second device 120 can send a request for auxiliary information to the third device 130.

[0072] In some example embodiments, the second device 120 transmits 504 a CP connection request for establishing a CP connection between the first device 110 and the third device 130 based on the information included in the connection request. The CP connection request is transmitted to the third device 130 via the fourth device 140.

[0073] In some example embodiments, the CP connection request is directly provided by the first device 110. For example, the CP connection request is a NAS message included in the connection request transmitted at 502. Alternatively, or additionally, the second device 120 generates the CP connection request based on the connection request. Specifically, the second device 120 extracts the information of the first device 110 included in the connection request, and generates the CP connection request based on the extracted information of the first device 110. The CP connection request may include a NAS registration request message, or a NAS service request message, or any other NAS message.

[0074] As such, information for establishing a CP connection between the first device 110 and the third device 130 may be provided to the third device 130 , so that the third device 130 may perform an authentication procedure on the first device 110 .

[0075] In some example embodiments, the CP connection request may preferably be transmitted through the CP connection of second device 120. In this way, the existing CP connection between second device 120 and third device 130 / fourth device 140 may be utilized to exchange necessary information of first device 110. Therefore, third device 130 is able to obtain information of first device 110 to authorize first device 110 before establishing an RRC connection for first device 110.

[0076] In this way, unnecessary signaling and processing overhead for the first device 110 may be avoided. This may also help reduce CP connection establishment process latency, because different levels of CP connection signaling (such as AS and NAS levels) can be combined into the same signaling message to a greater extent.

[0077] In some example embodiments, after receiving the CP connection request, the third device 130 may perform an authentication process for the first device 110 based on the information of the first device 110 included in the CP connection request. In some example embodiments, the authentication information may be a parameter included in the connection request. Alternatively, the first device 110 may provide the authentication information through other signaling or messages exchanged between the first device 110 and the second device 120. In other example embodiments, the authentication may be combined into the same authentication performed during the direct communication setup between the first device 110 and the second device 120, for example, in Figure 3 During mutual authentication as described in .

[0078] Additionally, in some example embodiments, after receiving the CP connection request, if the third device 130 is not suitable to be selected for the first device 110 , the third device 130 may perform a core device selection process (such as an existing AMF reselection function) for the first device 110 .

[0079] In some example embodiments, the third device 130 may determine whether to accept the CP connection request by using the authentication process discussed above or other criteria (such as network load, transport layer capabilities, etc.). If the third device 130 determines to accept the CP connection request, the third device 130 transmits 506 a request message to the fourth device 140 to initiate an RRC connection establishment process for the first device 110. For example, the request sent by the third device 130 may be an NG Application Protocol (NGAP) Initial Context Setup Request / UE Context Modification message to the fourth device 140, which includes a NAS message to the first device 110 (e.g., a NAS Registration Accept message in the case of receiving a Registration message, or a NAS Service Accept in the case of receiving a Service Request message, etc.). It should be noted that the above messages are shown for illustrative purposes only and do not imply any limitation. In other example embodiments, any suitable control message may be used.

[0080] Additionally, in some example embodiments, the third device 130 may support more than one relay solution (eg, L2 relay or L3 relay) for the first device 110 .

[0081] In some example embodiments, the third device 130 may support performing L2 relay for the first device 110 . Figure 6 An example CP protocol stack 600 for L2 relay using a 3GPP PC5 interface between a first device 110 and a second device 120 is illustrated and Figure 7 Another example CP protocol stack 700 for L2 relay using a non-3GPP interface between the first device 110 and the second device 120 is illustrated. For the purpose of illustration only and without implying any limitation, Figure 6 and Figure 7 , the first device 110 is a remote terminal device, the second device 120 is a relay device, the third device 130 is a core device and the fourth device 140 is a network device.

[0082] The first device 110 receives the Figure 6 The PC5 interface shown communicates with the second device 120, while the first device 110 communicates with the second device 120 via Figure 7 1 and 2. In addition, as shown in FIG. 1 , the second device 120 can communicate with the second device 120 through a non-3GPP link (such as WiFi or other short-range radio technology). Figure 6 and Figure 7 As shown, a logical connection may be established between the first device 110 and the fourth device 140 / the third device 130. Figure 6 and Figure 7 In these examples of the CP protocol stack for L2 relay shown, the CP process of the first device 110 in connected mode is expected to be similar to the CP process of a normal directly connected device, at least from the perspective of the network device and the core device.

[0083] Alternatively, in some example embodiments, the third device 130 may support performing L3 relay for the first device 110 . Figure 8 The CP protocol stack 800 for L3 relay is illustrated. For illustration purposes only and without implying any limitation, the first device 110 is a remote terminal device, the second device 120 is a relay device, the third device 130-1 is a gateway or a user plane function or AMF of the second device 120, the third device 130-2 is the AMF of the first device 110, and the fourth device 140 is a network device.

[0084] exist Figure 8 In the example CP protocol stack shown, the first device 110 and the second device 120 communicate with each other using the PC5-U protocol. The second device 120 and the fourth device 140 communicate with each other using the LTE-Uu or NR-Uu protocol. Figure 8 As shown, a general packet radio service (GPRS) tunneling protocol (GTP) for a user plane (GTP U) is used for communication between the fourth device 140 and the third device 130-1 and between the third device 130-1 and the third device 130-2. The third device 130-1 and the fourth device 140 use an Internet Protocol (IP) or use Figure 8 (Multiple) other intermediate devices not shown communicate with each other

[0085] Reference again Figure 5In the case where more than one relay solution (such as, L2 relay and L3 relay) is supported by the third device 130, the third device 130 can determine 505 the relay solution for the first device 110, and then later transmit a request message to the fourth device 140, for example, the request message can include a CP connection accept message, and the CP connection accept message includes the determined relay solution.

[0086] In some example embodiments, third device 130 may determine the relay solution based on the capability of first device 110 to support the relay solution. For example, if first device 110 only supports L2 relay or L3 relay, third device 130 may correspondingly determine that the relay solution for first device 110 is L2 relay or L3 relay.

[0087] Alternatively or additionally, in some example embodiments, the third device 130 may determine the relay solution based on the capability of the second device 120 to support the relay solution. For example, if the second device 120 only supports L2 relay or L3 relay, the third device 130 may correspondingly determine that the relay solution for the first device 110 is L2 relay or L3 relay.

[0088] Alternatively or additionally, in some example embodiments, the third device 130 may determine the relay solution based on the capability of the fourth device 140 to support the relay solution. For example, if the fourth device 140 only supports L2 relay or L3 relay, the third device 130 may correspondingly determine that the relay solution for the first device 110 is L2 relay or L3 relay.

[0089] Alternatively or additionally, in some example embodiments, the third device 130 may determine the relay solution based on the preference of the first device 110 for the relay solution. For example, if the first device 110 prefers L2 relay or L3 relay, the third device 130 may correspondingly determine that the relay solution for the first device 110 is L2 relay or L3 relay.

[0090] Alternatively or additionally, in some example embodiments, the third device 130 may determine the relay solution based on the preference of the second device 120 for the relay solution. For example, if the second device 120 prefers L2 relay or L3 relay, the third device 130 may correspondingly determine that the relay solution for the first device 110 is L2 relay or L3 relay.

[0091] Alternatively or additionally, in some example embodiments, the third device 130 may determine the relay solution based on the subscription information of the first device 110. For example, information of the relay solution for the first device 110 may be stored as a configuration in the subscription information. The third device 130 may obtain the subscription information of the first device 110 and determine the relay solution for the first device 110 accordingly.

[0092] Alternatively or additionally, in some example embodiments, the third device 130 may determine the relay solution based on the type of the received CP connection request, e.g., the registration / NAS signaling type (e.g., initial registration or registration update). For example, in the case where the CP connection request is an initial registration message, the third device 130 may determine whether the relay solution for the first device 110 is an L2 relay or an L3 relay according to the criteria discussed above, and in the case where the CP connection request is a registration update message, the third device 130 may determine whether the relay solution for the first device 110 is an L2 relay or an L3 relay according to the determined relay solution of the same registration.

[0093] Alternatively or additionally, in some example embodiments, the third device 130 may determine the relay solution based on priority information of the service for the first device 110. For example, some priorities of the service may be associated with certain service requirements. Therefore, if the information of the service includes a priority corresponding to a high requirement for service continuity, the L2 relay may be determined by the third device 130, and if the information of the service includes a priority corresponding to a low requirement for service continuity, the L3 relay may be determined by the third device 130.

[0094] Alternatively or additionally, in some example embodiments, the third device 130 may determine the relay solution based on the quality of service requirements for the services of the first device 110. For example, an L2 relay may correspond to a high quality of service requirement and an L3 relay may correspond to a low quality of service requirement, or vice versa. In another example embodiment, the third device 130 may determine the relay solution based on any combination of the above criteria, for example, the capabilities of the first device 110, the capabilities of the second device 120, the capabilities of the fourth device 140, the preferences of the first device 110, the preferences of the second device 120, the subscription information of the first device 110, the type of the received CP connection request, the priority information for the services of the first device 110, the quality of service requirements for the services of the first device 110, etc.

[0095] In some example embodiments, the determined relay solution may be explicitly indicated as an indication, for example, the request to the fourth device may include an indication of an L2 relay or an L3 relay. In an example embodiment, the NGAP message to the fourth device may include a new information element (IE) to indicate the determined relay solution. In some example embodiments, the determined relay solution may be implicitly indicated. For example, different NGAP procedures or messages may be used as implicit indications about the determined relay solution. For example, an NGAP UE context modification message may be used as an implicit indication of an L3 relay. From the perspective of the fourth device 140, the fourth device 140 triggers the establishment or update of the context of the second device 120 to relay the traffic of the first device 110 on an L2 level or an L3 level relay based on an explicit indication or implicit indication received from the third device 130. The NGAP initial context establishment request message may be used as an implicit indication of an L2 relay. After receiving the request (eg, the NGAP Initial Context Setup Request message), the fourth device 140 is triggered to setup a context for the L2 relay or the L3 relay of the first device 110 .

[0096] In this way, when more than one relay solution (such as L2 relay and L3 relay, etc.) is supported, after receiving the CP connection request from the second device 120, the third device 130 can determine the relay solution (such as L2 relay or L3 relay). In this way, a more flexible initial access process is achieved.

[0097] After receiving the CP connection accept message from the third device 130, the fourth device 140 initiates an RRC establishment procedure for the first device 110 to establish an RRC connection between the first device and the fourth device, and associates the established RRC connection with the CP connection between the first device and the third device.

[0098] In some example embodiments, fourth device 140 transmits 508 an RRC message (e.g., an RRC connection setup message or (multiple) other RRC messages) to the second device, the RRC message being used to establish an RRC connection between first device 110 and fourth device 140, and then second device 120 forwards 510 the RRC message to first device 110. After receiving the RRC message, first device 110 transmits 512 an RRC confirmation (e.g., an RRC connection setup complete message, or (multiple) other RRC messages) to second device 120, and then second device 120 transmits 514 the RRC confirmation to fourth device 140. In this way, the RRC message and the RRC confirmation are transmitted between first device 110 and fourth device 140 via second device 120. As a result, an RRC connection is established between first device 110 and fourth device 140.

[0099] In this way, the RRC connection establishment is triggered by the fourth device 140. Compared with the conventional initiation mechanism for the RRC connection, in the case where the RRC connection is triggered only by the terminal side, the initiation mechanism for the RRC connection is more efficient because it is initiated only after the third device 130 determines that the CP connection between the first device 110 and the third device 130 can be established.

[0100] In addition, there are several ways to initiate an RRC connection between the first device 110 and the fourth device 140. In some example embodiments, in order to enable the fourth device 140 to initiate the RRC connection establishment procedure, in addition to the relevant radio bearer information and the relevant configuration, the RRC connection setup message or (multiple) other RRC messages may be extended to include the cell radio network temporary identifier (C-RNTI) of the first device 110. In other example embodiments, a new RRC message may be introduced to enable the fourth device 140 to initiate the RRC connection establishment procedure.

[0101] In some example embodiments, corresponding information about the CP connection establishment message (e.g., registration acceptance message) between the first device 110 and the third device 130 may also be included in the RRC connection establishment message or (multiple) other RRC messages. Alternatively, the fourth device 140 may initiate a special paging message including the C-RNTI of the first device 110 to the first device 110 via the second device 120. The special paging message triggers the first device 110 to send an RRC connection establishment / re-establishment message. It should be noted that the above information is shown for illustrative purposes only and does not imply any limitation. In other example embodiments, any suitable control message may be used.

[0102] In some example embodiments, the RRC message for the connection setup message and the special paging message may be transmitted by using an existing signaling radio bearer (SRB) of second device 120, a specific RRC message of second device 120, or a new SRB dedicated to relaying RRC signaling messages.

[0103] After receiving the RRC confirmation from the second device 120, the fourth device 140 transmits 516 a CP connection confirmation message to the third device 130 to confirm the CP connection establishment of the first device 110. In some example embodiments, the fourth device 140 transmits an NGAP initial context setup response / NGAP UE context modification response to the third device 130. It should be noted that the above messages are shown for illustration purposes only and do not imply any limitation. In other example embodiments, any suitable control message may be used.

[0104] According to the present disclosure, the existing connection between the second device 120 and the third device 130 / fourth device 140 can be used to exchange the necessary information of the first device 110, so that the third device 130 can first authenticate and authorize the first device 110, and then trigger the CP connection establishment process involving the RRC establishment process. In this way, the RRC initiation mechanism is more flexible and unnecessary RRC connections caused by unsuccessful authentication can be avoided. In addition, using the above-mentioned improved process, the delay of initial access is shortened and the signaling overhead is reduced.

[0105] Furthermore, in the case where both L2 relay and L3 relay are supported by the third device 130, the third device 130 may determine the relay solution. In this way, the relay level selection mechanism is more flexible.

[0106] In addition, in some example embodiments, if the first device 110 needs to be authenticated through an application function instead of or in addition to cellular network authentication, the present disclosure can be extended to support CN-initiated NAS horizontal CP connection establishment (e.g., triggered by an AF function) after successful application authentication of the first device 110.

[0107] Fig. 9 1 is a flowchart of an example method 900 implemented at the first device 110 according to some example embodiments of the present disclosure. For the purpose of discussion, the method 900 will be described from the perspective of the first device 110. Figure 1 It is to be understood that the method 900 may include additional blocks not shown and / or may omit some of the blocks shown, and the scope of the present disclosure is not limited in this regard.

[0108] At 910, the first device 110 transmits a connection request to the second device 120. The connection request is used to establish a CP connection between the first device 110 and the third device 130. The connection request includes information of the first device 110 for establishing a CP connection between the first device 110 and the third device 130, so that the second device 120 transmits the CP connection request to the third device 130 based on the information.

[0109] In some exemplary embodiments, the information includes at least one of the following: an indication of the type of NAS connection to be established between the first device 110 and the third device 130, an identifier of the first device 110, or information of a network slice requested by the first device 110.

[0110] In some example embodiments, the information is an Initiate NAS message included in a connection request.

[0111] In some example embodiments, the connection request is one of: a direct communication request and a relay connection request, and wherein the initiating NAS message is a registration request or a service request.

[0112] In some example embodiments, further comprising: providing authentication information of the first device 110 to the second device 120 to enable the second device 120 to send a request for auxiliary information for transmitting the CP connection request to the third device 130 .

[0113] At 920 , the first device 110 receives an RRC message from the second device 120 , where the RRC message is used to establish an RRC connection between the first device 110 and the fourth device 140 .

[0114] In some example embodiments, the RRC message includes a C-RNTI of first device 110 .

[0115] In some example embodiments, the first device 110 and the second device 120 are terminal devices, the third device 130 is a core device, and the fourth device 140 is a network device.

[0116] Fig.10 FIG. 1 is a flowchart of an example method 1000 implemented at the second device 120 according to some example embodiments of the present disclosure. For the purpose of discussion, reference will be made to Figure 1 The method 1000 is described from the perspective of the second device 120. It should be understood that the method 1000 may include additional blocks not shown and / or may omit some of the shown blocks, and the scope of the present invention is not limited in this regard.

[0117] At 1010, the second device 120 receives a connection request from the first device 110, the connection request being used to establish a CP connection between the first device 110 and the third device 130. The connection request includes information of the first device 110 for establishing a CP connection between the first device 110 and the third device 130.

[0118] In some example embodiments, the information includes at least one of: an indication of the type of NAS connection to be established between the first device 110 and the third device 130; an identification of the first device 110; or information of a network slice requested by the first device 110.

[0119] In some example embodiments, the information is an Initiate NAS message included in a connection request.

[0120] In some example embodiments, the connection request is one of: a direct communication request and a relay connection request, and the initiating NAS message is a registration request or a service request.

[0121] At 1020 , the second device 120 transmits a CP connection request to the third device 130 based on the information.

[0122] In some example embodiments, the second device 120 transmits the CP connection request by: obtaining authentication information of the first device 110 from the first device 110; based on the obtained authentication information, sending a request for auxiliary information to be used for transmitting the CP connection request to the third device 130; and transmitting the CP connection request to the third device 130 based on the information received from the first device 110 and the auxiliary information.

[0123] At 1030, the second device 120 receives an RRC message from the fourth device 140, the RRC message being used to establish an RRC connection between the first device 110 and the fourth device 140. The RRC message is transmitted after receiving the CP connection accept message from the third device 130.

[0124] In some example embodiments, the RRC message includes a C-RNTI of first device 110 .

[0125] At 1040 , the second device 120 transmits an RRC message to the first device 110 .

[0126] In some example embodiments, the first device 110 and the second device 120 are terminal devices, the third device 130 is a core device, and the fourth device 140 is a network device.

[0127] Fig.11 FIG. 1 is a flowchart showing an example method 1100 implemented at the third device 130 according to some example embodiments of the present disclosure. For the purpose of discussion, reference will be made to Figure 1 The method 1100 is described from the perspective of the third device 130. It should be understood that the method 1100 may include additional blocks not shown and / or may omit some of the shown blocks, and the scope of the present disclosure is not limited in this regard.

[0128] At 1110, the third device 130 receives a CP connection request from the second device 120. The CP connection request is generated based on information of the first device 110 for establishing a CP connection between the first device 110 and the third device 130.

[0129] At 1120 , the third device 130 transmits a CP connection accept message to the fourth device 140 , so that the fourth device 140 transmits an RRC message to the second device 120 , where the RRC message is used to establish an RRC connection between the first device 110 and the fourth device 140 .

[0130] In some example embodiments, the third device 130 determines a relay solution for the first device 110 based on at least one of: a capability of the first device to support a relay solution; a capability of the second device 120 to support a relay solution; a capability of the fourth device 140 to support a relay solution; a preference of the first device 110 for the relay solution; a preference of the second device 120 for the relay solution; subscription information of the first device 110; a type of CP connection request received; priority information for a service of the first device 110; or a quality of service requirement for a service of the first device 110.

[0131] In some example embodiments, the third device 130 provides the assistance information of the first device 110 to the second device 120 in response to a request from the second device 120 to enable the second device 120 to transmit the CP connection request based on the provided assistance information.

[0132] In some example embodiments, the first device 110 and the second device 120 are terminal devices, the third device 130 is a core device, and the fourth device 140 is a network device.

[0133] Fig.12 FIG. 1 is a flowchart showing an example method 1200 implemented at the fourth device 140 according to some example embodiments of the present disclosure. For the purpose of discussion, reference will be made to Figure 1 The method 1200 is described from the perspective of the fourth device 140. It should be understood that the method 1200 may include additional blocks not shown and / or may omit some of the shown blocks, and the scope of the present invention is not limited in this respect.

[0134] At block 1210, the fourth device 140 receives a CP connection accept message from the third device 130. The CP connection accept message is transmitted after receiving a CP connection request from the second device 120, the CP connection request being used to establish a CP connection between the first device 110 and the third device 130.

[0135] In block 1220 , the fourth device 140 transmits a CP connection accept message to the fourth device 140 , so that the fourth device 140 transmits an RRC message to the second device 120 , the RRC message being used to establish an RRC connection between the first device 110 and the fourth device 140 .

[0136] In some example embodiments, the fourth device 140 receives a CP connection accept message including an indication of a relay solution for the first device 110 , and establishes a user plane (UP) connection between the fourth device 140 and the first device 110 based on the received relay solution for the first device 110 .

[0137] In some example embodiments, the RRC message includes a C-RNTI of first device 110 .

[0138] In some example embodiments, the first device 110 and the second device 120 are terminal devices, the third device 130 is a core device, and the fourth device 140 is a network device.

[0139] In some example embodiments, the first device capable of performing any of the methods 900 may include a component for performing the corresponding operation of the method 900. The component may be implemented in any suitable form. For example, the component may be implemented in a circuit system or a software module. The first device may be implemented as or included in the first device 110.

[0140] In some example embodiments, the first device includes a component for transmitting a connection request to the second device, the connection request being used to establish a CP connection between the first device and the third device. The connection request includes information of the first device for establishing a CP connection between the first device and the third device, so that the second device can transmit the CP connection request to the third device based on the information. The first device also includes a component for receiving an RRC message from the second device, the RRC message being used to establish an RRC connection between the first device and the fourth device. The RRC message is transmitted by the fourth device after receiving a CP connection acceptance message from the third device.

[0141] In some example embodiments, the information includes at least one of: an indication of the type of non-access stratum, NAS, connection to be established between the first device and the third device, an identification of the first device, or information of a network slice requested by the first device.

[0142] In some example embodiments, the information is an Initiate NAS message included in a connection request.

[0143] In some example embodiments, the connection request is one of: a direct communication request and a relay connection request, and wherein the initiating NAS message is a registration request or a service request.

[0144] In some example embodiments, the first device further includes means for providing authentication information of the first device to the second device to enable the second device to transmit a request for auxiliary information for transmitting the CP connection request to the third device.

[0145] In some example embodiments, the RRC message includes a C-RNTI of the first device.

[0146] In some example embodiments, the first device and the second device are terminal devices, the third device is a core device, and the fourth device is a network device.

[0147] In some example embodiments, the second device capable of performing any of the methods 1000 may include a component for performing the corresponding operation of the method 1000. The component may be implemented in any suitable form. For example, the component may be implemented in a circuit system or a software module. The second device may be implemented as or included in the second device 120.

[0148] In some example embodiments, the second device includes a component for receiving a connection request from the first device, the connection request being used to establish a connection between the first device and the third device. The connection request includes information of the first device for establishing a CP connection between the first device and the third device. The second device also includes a component for transmitting the CP connection request to the third device based on the information. The second device also includes a component for receiving an RRC message from the fourth device, the RRC message being used to establish an RRC connection between the first device and the fourth device. The RRC message is transmitted after receiving a CP connection acceptance message from the third device. The second device also includes a component for transmitting the RRC message to the first device.

[0149] In some example embodiments, the information includes at least one of: an indication of the type of non-access stratum, NAS, connection to be established between the first device and the third device; an identification of the first device; or information of a network slice requested by the first device.

[0150] In some example embodiments, the information is an Initiate NAS message included in a connection request.

[0151] In some example embodiments, the connection request is one of: a direct communication request and a relay connection request, and the initiating NAS message is a registration request or a service request.

[0152] In some example embodiments, the second device includes a component for obtaining authentication information of the first device from the first device; a component for sending a request for auxiliary information for transmitting a CP connection request to a third device based on the obtained authentication information; and a component for transmitting the CP connection request to the third device based on the information received from the first device and the auxiliary information.

[0153] In some example embodiments, the RRC message includes a C-RNTI of the first device.

[0154] In some example embodiments, the first device and the second device are terminal devices, the third device is a core device, and the fourth device is a network device.

[0155] In some example embodiments, the third device capable of performing any of the methods 1100 may include a component for performing the corresponding operation of the method 1100. The component may be implemented in any suitable form. For example, the component may be implemented in a circuit system or a software module. The third device may be implemented as or included in the third device 130.

[0156] In some example embodiments, the third device includes a component for receiving a CP connection request from the second device. The CP connection request is generated based on information of the first device for establishing a CP connection between the first device and the third device. The third device also includes a component for transmitting a CP connection accept message to the fourth device, so that the fourth device transmits an RRC message to the second device, the RRC message being used to establish an RRC connection between the first device and the fourth device.

[0157] In some example embodiments, the third apparatus further comprises means for determining a relay solution for the first apparatus; and means for transmitting a CP connection accept message including an indication of the determined relay solution to the fourth apparatus.

[0158] In some example embodiments, the third device includes a component for determining a relay solution for the first device based on at least one of: the capability of the first device to support the relay solution; the capability of the second device to support the relay solution; the capability of the fourth device to support the relay solution; the preference of the first device for the relay solution; the preference of the second device for the relay solution; subscription information of the first device; the type of CP connection request received; priority information for the service of the first device; or quality of service requirements for the service of the first device.

[0159] In some example embodiments, the third device includes means for providing the assistance information of the first device to the second device in response to a request from the second device, so as to enable the second device to transmit the CP connection request based on the provided assistance information.

[0160] In some example embodiments, the first device and the second device are terminal devices, the third device is a core device, and the fourth device is a network device.

[0161] In some example embodiments, the fourth device capable of performing any of the methods 1200 may include a component for performing the corresponding operation of the method 1200. The component may be implemented in any suitable form. For example, the component may be implemented in a circuit system or a software module. The fourth device may be implemented as or included in the fourth device 140.

[0162] In some example embodiments, the fourth device includes a component for receiving a CP connection accept message from the third device. The CP connection accept message is transmitted after receiving a CP connection request from the second device, the CP connection request being used to establish a CP connection between the first device and the third device. The fourth device also includes a component for transmitting an RRC message to the second device, the RRC message being used to establish an RRC connection between the first device and the fourth device.

[0163] In some example embodiments, the fourth device includes a component for receiving a CP connection accept message from the third device, the CP connection accept message including an indication of a relay solution for the first device; and a component for establishing a user plane (UP) connection between the fourth device and the first device based on the received relay solution for the first device.

[0164] In some example embodiments, the RRC message includes a C-RNTI of the first device.

[0165] In some example embodiments, the first device and the second device are terminal devices, the third device is a core device, and the fourth device is a network device.

[0166] Fig.13 1 is a simplified block diagram of a device 1300 suitable for implementing an example embodiment of the present disclosure. The device 1300 may be provided to implement a communication device, such as Figure 1 The first device 110, the second device 120, the third device 130 or the fourth device 140 shown. As shown in the figure, the device 1300 includes one or more processors 1310, one or more memories 1320 coupled to the processor 1310, and one or more communication modules 1340 coupled to the processor 1310.

[0167] The communication module 1340 is used for two-way communication. The communication module 1340 has one or more communication interfaces to facilitate communication with one or more other modules or devices. The communication interface may represent any interface necessary to communicate with other network elements. In some example embodiments, the communication module 1340 may include at least one antenna.

[0168] Processor 1310 may be of any type suitable for the local technology network and may include, as non-limiting examples, one or more of: a general purpose computer, a special purpose computer, a microprocessor, a digital signal processor (DSP), and a processor based on a multi-core processor architecture. Device 1300 may have multiple processors, such as application specific integrated circuit chips, which are time-slaved to a clock synchronized with a main processor.

[0169] The memory 1320 may include one or more non-volatile memories and one or more volatile memories. Examples of non-volatile memories include, but are not limited to, read-only memory (ROM) 1324, electrically programmable read-only memory (EPROM), flash memory, hard disk, compact disk (CD), digital video disk (DVD), optical disk, laser disk, and other magnetic storage and / or optical storage. Examples of volatile memories include, but are not limited to, random access memory (RAM) 1322 and other volatile memories that do not persist during power outages.

[0170] Computer program 1330 includes computer executable instructions that are executed by associated processor 1310. Program 1330 may be stored in a memory, such as ROM 1324. Processor 1310 may perform any suitable actions and processes by loading program 1330 into RRM 1322.

[0171] The exemplary embodiments of the present disclosure may be implemented by the program 1330 so that the device 1300 may execute the Figures 9 to 12 Any process of the present disclosure discussed. The exemplary embodiments of the present disclosure may also be implemented by hardware or by a combination of software and hardware.

[0172] In some example embodiments, program 1330 may be tangibly embodied in a computer-readable medium that may be included in device 1300 (such as memory 1320) or in other storage devices accessible by device 1300. Device 1300 may load program 1330 from the computer-readable medium to RAM 1322 for execution. Computer-readable media may include any type of tangible, non-volatile storage, such as ROM, EPROM, flash memory, hard disk, CD, DVD, etc. Fig.14 An example of a computer readable medium 1400 is shown, which may be in the form of a CD, DVD, or other optical storage disk. The computer readable medium has a program 1330 stored thereon.

[0173] In general, various example embodiments of the present disclosure may be implemented in hardware or dedicated circuits, software, logic, or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software that may be executed by a controller, microprocessor, or other computing device. Although various aspects of the example embodiments of the present disclosure are illustrated and described as block diagrams, flow charts, or using some other graphical representations, it should be understood that, as non-limiting examples, the boxes, devices, systems, techniques, or methods described herein may be implemented in hardware, software, firmware, dedicated circuits or logic, general hardware or controllers or other computing devices, or some combination thereof.

[0174] The present disclosure also provides at least one computer program product tangibly stored on a non-concurrent computer-readable storage medium. The computer program product includes computer executable instructions, such as those included in a program module, which are executed in a device on a target real or virtual processor to perform the above referenced Figures 9 to 12 Any method described herein. Typically, program modules include routines, programs, libraries, objects, classes, components, data structures, etc. that perform specific tasks or implement specific abstract data types. In various example embodiments, the functions of program modules can be combined or split between program modules as needed. Machine executable instructions for program modules can be executed in local or distributed devices. In distributed devices, program modules can be located in both local and remote storage media.

[0175] The program code for executing the method of the present disclosure can be written in any combination of one or more programming languages. These program codes can be provided to a processor or controller of a general-purpose computer, a special-purpose computer or other programmable data processing device so that the program code enables the functions / operations specified in the flow chart and / or block diagram to be realized when executed by the processor or controller. The program code can be executed entirely on the machine, partially on the machine, as an independent software package, partially on the machine and partially on a remote machine or entirely on a remote machine or server.

[0176] In the context of the present disclosure, computer program codes or related data may be carried by any suitable carrier to enable a device, apparatus or processor to perform various processes and operations as described above. Examples of carriers include signals, computer readable media, etc.

[0177] The computer readable medium may be a computer readable signal medium or a computer readable storage medium. The computer readable medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared or semiconductor systems, devices or apparatuses, or any suitable combination of the foregoing. More specific examples of computer readable storage media would include an electrical connection with one or more wires, a portable computer floppy disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0178] In addition, although operations are described in a particular order, this should not be understood as requiring such operations to be performed in the particular order shown or in sequence, or to perform all of the operations shown to obtain the desired result. In some cases, multitasking and parallel processing may be advantageous. Similarly, although several specific implementation details are included in the above discussion, these should not be interpreted as limitations on the scope of the present disclosure, but should be interpreted as descriptions of features that may be specific to a particular embodiment. Certain features described in the context of separate example embodiments may also be implemented in combination in a single embodiment. On the contrary, the various features described in the context of a single embodiment may also be implemented separately or in any suitable sub-combination in multiple example embodiments.

[0179] Although the disclosure has been described in language specific to structural features and / or methodological acts, it will be understood that the disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

1. A first device, comprising: at least one processor; as well as at least one memory including computer program code; wherein the at least one memory and the computer program code are configured to, together with the at least one processor, cause the first device to: transmitting a connection request to a second device, the connection request being used to establish a control plane connection between the first device and a third device, the connection request including information of the first device used to establish the control plane connection between the first device and the third device, so that the second device can transmit the control plane connection request to the third device based on the information; as well as A radio resource control message is received from the second device, the radio resource control message being used to establish a radio resource control connection between the first device and a fourth device, the radio resource control message being transmitted by the fourth device in response to a connection accept message from the third device.

2. The first device according to claim 1, wherein the information comprises at least one of the following: an indication of a type of non-access stratum connection to be established between the first device and the third device, an identification of the first device, or Information about the network slice requested by the first device.

3. The first device of claim 1, wherein the information is an Initiate Non-Access Stratum message included in the connection request. 4 . The first device of claim 3 , wherein the connection request is one of: a direct communication request and a relay connection request, and wherein the initiating non-access stratum message is a registration request or a service request.

5. The first device of claim 1, wherein the at least one memory and the computer program code are configured to, with the at least one processor, further cause the first device to: The authentication information of the first device is provided to the second device to enable the second device to send a request to the third device for auxiliary information used to transmit the control plane connection request. 6 . The first device of claim 1 , wherein the radio resource control message comprises a cell radio network temporary identifier of the first device. 7 . The first device according to claim 1 , wherein the first device and the second device are terminal devices, the third device is a core device, and the fourth device is a network device.

8. A second device, comprising: at least one processor; as well as at least one memory including computer program code; wherein the at least one memory and the computer program code are configured to, together with the at least one processor, cause the second device to: receiving a connection request from a first device, the connection request being used to establish a control plane connection between the first device and a third device, the connection request including information of the first device used to establish the control plane connection between the first device and the third device; Based on the information, transmitting a control plane connection request to the third device; receiving a radio resource control message from a fourth device, the radio resource control message being used to establish a radio resource control connection between the first device and the fourth device, the radio resource control message being transmitted in response to a control plane connection accept message from the third device; and The radio resource control message is transmitted to the first device.

9. The second device according to claim 8, wherein the information comprises at least one of the following: an indication of a type of non-access stratum connection to be established between the first device and the third device; an identification of the first device; or Information about the network slice requested by the first device.

10. The second device of claim 8, wherein the information is an Initiate Non-Access Stratum message included in the connection request. 11 . The second device according to claim 10 , wherein the connection request is one of: a direct communication request and a connection relay request, and the initiating non-access stratum message is a registration request or a service request.

12. The second device of claim 8, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the second device to transmit the control plane connection request by: obtaining authentication information of the first device from the first device; Based on the acquired authentication information, sending a request to the third device for auxiliary information to be used for transmitting the control plane connection request; and The control plane connection request is transmitted to the third device based on the information received from the first device and the auxiliary information.

13. The second device of claim 8, wherein the radio resource control message comprises a cell radio network temporary identifier of the first device.

14. The second device according to claim 8, wherein the first device and the second device are terminal devices, the third device is a core device, and the fourth device is a network device.

15. A third device, comprising: at least one processor; as well as at least one memory including computer program code; wherein the at least one memory and the computer program code are configured to, together with the at least one processor, cause the third device to: receiving a control plane connection request from a second device, the control plane connection request being generated based on information of the first device for establishing a control plane connection between the first device and the third device; as well as A control plane connection accept message is transmitted to a fourth device to enable the fourth device to transmit a radio resource control message to the second device, the radio resource control message being used to establish a radio resource control connection between the first device and the fourth device.

16. The third device of claim 15, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the third device to transmit the control plane connection accept message by: determining a relay solution for the first device; and The control plane connection accept message is transmitted to the fourth device, wherein the control plane connection accept message includes the determined relay solution.

17. The third device of claim 16, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the third device to determine a relay solution for the first device by: Determine a relay solution for the first device according to at least one of the following: the capability of the first device to support a relay solution; the capability of the second device to support a relay solution; The fourth device has the capability of supporting a relay solution; the first device's preference for a relay solution; the second device's preference for a relay solution; subscription information of the first device; a type of the control plane connection request received; priority information for services of the first device; or A quality of service requirement for a service of the first device.

18. The third device according to claim 15, wherein the at least one memory and the computer program code are configured to, together with the at least one processor, further cause the third device to: In response to the request from the second device, the assistance information of the first device is provided to the second device, so that the second device can transmit the control plane connection request based on the provided assistance information.

19. The third device according to claim 15, wherein the first device and the second device are terminal devices, the third device is a core device, and the fourth device is a network device.

20. A fourth device, comprising: at least one processor; as well as at least one memory including computer program code; wherein the at least one memory and the computer program code are configured to, together with the at least one processor, cause the fourth device to: receiving a control plane connection accept message from the third device, the control plane connection accept message being transmitted in response to receiving a control plane connection request from the second device, the control plane connection request being used to establish a control plane connection between the first device and the third device; as well as A radio resource control message is sent to the second device, where the radio resource control message is used to establish a radio resource control connection between the first device and the fourth device.

21. The fourth device of claim 20, wherein the at least one memory and the computer program code are configured to, together with the at least one processor, cause the fourth device to receive the control plane connection accept message by: receiving, from the third device, the control plane connection accept message including a relay solution for the first device; and Based on the received relay solution for the first device, a user plane connection is established between the fourth device and the first device.

22. The fourth device of claim 20, wherein the radio resource control message comprises a cell radio network temporary identifier of the first device.

23. The fourth device according to claim 20, wherein the first device and the second device are terminal devices, the third device is a core device, and the fourth device is a network device.

24. A method comprising: transmitting, at a first device, a connection request to a second device, the connection request being used to establish a control plane connection between the first device and a third device, the connection request comprising information of the first device used to establish the control plane connection between the first device and the third device, so that the second device can transmit the control plane connection request to the third device based on the information; as well as A radio resource control message is received from the second device, the radio resource control message being used to establish a radio resource control connection between the first device and a fourth device, the radio resource control message being transmitted by the fourth device in response to a control plane connection accept message from the third device.

25. The method of claim 24, wherein the information includes at least one of: an indication of a type of non-access stratum connection to be established between the first device and the third device, an identification of the first device, or Information about the network slice requested by the first device.

26. The method of claim 24, wherein the information is an Initiate Non-Access Stratum message included in the connection request.

27. The method of claim 26, wherein the connection request is one of: a direct communication request and a connection relay request, and wherein the initiating non-access stratum message is a registration request or a service request.

28. The method of claim 24, further comprising: The authentication information of the first device is provided to the second device to enable the second device to send a request to the third device for auxiliary information used to transmit the control plane connection request.

29. The method of claim 24, wherein the radio resource control message includes a cell radio network temporary identifier of the first device.

30. The method of claim 24, wherein the first device and the second device are terminal devices, the third device is a core device, and the fourth device is a network device.

31. A method comprising: receiving, at a second device, a connection request from a first device, the connection request being used to establish a control plane connection between the first device and a third device, the connection request including information of the first device used to establish the control plane connection between the first device and the third device; Based on the information, transmitting a control plane connection request to the third device; receiving a radio resource control message from a fourth device, the radio resource control message being used to establish a radio resource control connection between the first device and the fourth device, the radio resource control message being transmitted in response to a control plane connection accept message from the third device; and The radio resource control message is transmitted to the first device.

32. The method of claim 31 , wherein the information includes at least one of: an indication of a type of non-access stratum connection to be established between the first device and the third device; an identification of the first device; or Information about the network slice requested by the first device.

33. The method of claim 31, wherein the information is an Initiate Non-Access Stratum message included in the connection request.

34. The method of claim 33, wherein the connection request is one of: a direct communication request and a relay connection request, and the initiating non-access stratum message is a registration request or a service request.

35. The method of claim 31 , wherein transmitting the control plane connection request comprises: obtaining authentication information of the first device from the first device; sending, based on the obtained authentication information, a request to the third device for auxiliary information to be used for transmitting the control plane connection request; as well as The control plane connection request is transmitted to the third device based on the information received from the first device and the auxiliary information.

36. The method of claim 31, wherein the radio resource control message includes a cell radio network temporary identifier of the first device.

37. The method of claim 31, wherein the first device and the second device are terminal devices, the third device is a core device, and the fourth device is a network device.

38. A method comprising: receiving, at a third device, a control plane connection request from a second device, the control plane connection request being generated based on information of the first device for establishing a control plane connection between the first device and the third device; as well as A control plane connection accept message is transmitted to a fourth device to enable the fourth device to transmit a radio resource control message to the second device, the radio resource control message being used to establish a radio resource control connection between the first device and the fourth device.

39. The method of claim 38, wherein transmitting the control plane connection accept message comprises: determining a relay solution for the first device; as well as The control plane connection accept message is transmitted to the fourth device, the control plane connection accept message including an indication of the determined relay solution.

40. The method of claim 39, wherein determining a relay solution for the first device comprises: Determine a relay solution for the first device according to at least one of the following: the capability of the first device to support a relay solution; the capability of the second device to support a relay solution; The fourth device has the capability of supporting a relay solution; the first device's preference for a relay solution; the second device's preference for a relay solution; subscription information of the first device; a type of the control plane connection request received; priority information for services of the first device; or A quality of service requirement for a service of the first device.

41. The method of claim 38, further comprising: In response to the request from the second device, the assistance information of the first device is provided to the second device, so that the second device can transmit the control plane connection request based on the provided assistance information.

42. The method of claim 38, wherein the first device and the second device are terminal devices, the third device is a core device, and the fourth device is a network device.

43. A method comprising: receiving, at a fourth device, a control plane connection accept message from a third device, the control plane connection accept message being transmitted in response to receiving a control plane connection request from a second device, the control plane connection request being used to establish a control plane connection between the first device and the third device; and A radio resource control message is transmitted to the second device, where the radio resource control message is used to establish a radio resource control connection between the first device and the fourth device.

44. The method of claim 43, wherein receiving the control plane connection accept message comprises: receiving the control plane connection accept message from the third device, the control plane connection accept message including an indication of a relay solution for the first device; as well as Based on the received relay solution for the first device, a user plane connection is established between the fourth device and the first device.

45. The method of claim 43, wherein the radio resource control message includes a cell radio network temporary identifier of the first device.

46. ​​The method of claim 43, wherein the first device and the second device are terminal devices, the third device is a core device, and the fourth device is a network device.

47. A first device, comprising: means for transmitting a connection request to a second device, the connection request being used to establish a control plane connection between the first device and a third device, the connection request comprising information of the first device for establishing the control plane connection between the first device and the third device, so that the second device can transmit the control plane connection request to the third device based on the information; as well as means for receiving a radio resource control message from the second device, the radio resource control message being used to establish a radio resource control connection between the first device and a fourth device, the radio resource control message being transmitted by the fourth device in response to a control plane connection accept message from the third device.

48. A second device, comprising: means for receiving a connection request from a first device, the connection request being used to establish a control plane connection between the first device and a third device, the connection request comprising information of the first device for establishing the control plane connection between the first device and the third device; means for transmitting a control plane connection request to the third device based on the information; means for receiving a radio resource control message from a fourth device, the radio resource control message being used to establish a radio resource control connection between the first device and the fourth device, the radio resource control message being transmitted in response to a control plane connection accept message from the third device; as well as Means for transmitting the radio resource control message to the first device.

49. A third device, comprising: means for receiving a control plane connection request from a second device, the control plane connection request being generated based on information of the first device for establishing a control plane connection between the first device and the third device; as well as Means for transmitting a control plane connection accept message to a fourth device to enable the fourth device to transmit a radio resource control message to the second device, the radio resource control message being used to establish a radio resource control connection between the first device and the fourth device.

50. A fourth device, comprising: means for receiving a control plane connection accept message from a third device, the control plane connection accept message being transmitted in response to receiving a control plane connection request from a second device, the control plane connection request being used to establish a control plane connection between the first device and the third device; as well as Means for transmitting a radio resource control message to the second apparatus, the radio resource control message being used to establish a radio resource control connection between the first apparatus and the fourth apparatus.

51. A computer-readable medium comprising program instructions for causing an apparatus to at least perform the method according to any one of claims 24 to 30, claims 31 to 37, claims 38 to 42, or claims 43 to 46.

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