Apparatus and method for communication

Abstract

Example embodiments of the present disclosure relate to packet rerouting in a communication network. A first device receives a request from a second device to establish at least one tunnel between the first device and a third device. The first device sends tunnel information about the at least one tunnel to be established between the first device and the third device to the second device. The first device receives at least one uplink packet destined for the first device from a fourth device via the third device and the at least one tunnel. This solution can avoid uplink packet loss, for example, during donor-DU inter-migration. In addition, this solution does not violate security policies in the transport network and the IAB-donor-DU. In other words, source filtering can be applied normally to the rerouted packets.

Description

Technical Field

[0001] Embodiments of the present disclosure relate generally to the field of telecommunications, and more particularly to devices, methods, apparatuses, and computer-readable storage media for rerouting packets in a communication network. Background Art

[0002] The communication system may include one or more integrated access and backhaul (IAB) nodes. The IAB donor has a wired / fiber connection to the core network. It can be implemented as a gNB that terminates the wireless backhaul radio interface from one or more IAB nodes. The IAB donor can serve directly connected IAB nodes and IAB nodes linked via multiple wireless backhaul hops. The IAB donor can also serve directly connected terminal devices. The IAB node can also serve the connected terminal device and other connected child IAB nodes. The IAB donor may include a centralized unit (CU) and one or more distributed units (DUs).

[0003] An IAB node may include a DU (IAB-DU) and a mobile terminal (IAB-MT), wherein the IAB-MT maintains a connection with one or more upstream nodes (e.g., using dual connectivity). An IAB node may serve one or more terminal devices that are directly connected to the IAB node.

[0004] The IAB topology in the communication system may be non-static in that migration may be performed, eg, handover may be performed for an IAB-MT based on signal strength, signal quality, and other factors. Summary of the Invention

[0005] Generally speaking, example embodiments of the present disclosure provide a scheme for rerouting packets in a communication network. If any, embodiments that do not fall within the scope of the claims should be construed as examples for understanding the various embodiments of the present disclosure.

[0006] 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. 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: receive a request from a second device to establish at least one tunnel between the first device and a third device; send tunnel information regarding the at least one tunnel to be established between the first device and the third device to the second device; and receive at least one uplink packet destined for the first device from a fourth device via the third device and the at least one tunnel.

[0007] 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. 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: send a request to a first device to establish at least one tunnel between the first device and a third device, for forwarding at least one uplink packet from a fourth device and destined for the first device from the third device to the first device; receive tunnel information about the at least one tunnel from the first device; provide the tunnel information to the third device for establishing the at least one tunnel; and provide identification information about at least one uplink packet to be forwarded from the third device to the first device via the at least one tunnel to the third device.

[0008] 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. 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: obtain tunnel information about at least one tunnel to be established between the third device and the first device from a second device; obtain identification information about at least one uplink packet from the second device, the at least one uplink packet originating from a fourth device and destined for the first device, and the at least one uplink packet to be forwarded to the first device via the at least one tunnel and the third device; and, if it is determined that the uplink packet received from the fourth device includes the obtained identification information, forward the received uplink packet to the first device via one of the at least one tunnel.

[0009] In a fourth aspect, a method is provided. The method may be performed by a first device and includes: receiving, at the first device, a request from a second device to establish at least one tunnel between the first device and a third device; sending, to the second device, tunnel information regarding the at least one tunnel to be established between the first device and the third device; and receiving, from a fourth device via the third device and the at least one tunnel, at least one uplink packet destined for the first device.

[0010] In a fifth aspect, a method is provided. The method may be performed by a second device and includes: sending a request from the second device to the first device to establish at least one tunnel between the first device and a third device, for forwarding at least one uplink packet from a fourth device and destined for the first device from the third device to the first device; receiving tunnel information about the at least one tunnel from the first device; providing the tunnel information to the third device for establishing the at least one tunnel; and providing identification information about the at least one uplink packet to be forwarded from the third device to the first device through the at least one tunnel to the third device.

[0011] In a sixth aspect, a method is provided. The method may be performed by a third device and includes: acquiring, at the third device, tunnel information about at least one tunnel to be established between the third device and a first device from a second device; acquiring, from the second device, identification information about at least one uplink packet, the at least one uplink packet originating from a fourth device and destined for the first device, and the at least one uplink packet to be forwarded to the first device via the at least one tunnel and the third device; and if it is determined that the uplink packet received from the fourth device includes the acquired identification information, forwarding the received uplink packet to the first device via one of the at least one tunnel.

[0012] In a seventh aspect, a first device is provided. The first device includes means for: receiving, at the first device, a request from a second device to establish at least one tunnel between the first device and a third device; sending tunnel information regarding the at least one tunnel to be established between the first device and the third device to the second device; and receiving, via the third device and the at least one tunnel, at least one uplink packet destined for the first device from a fourth device.

[0013] In an eighth aspect, a second device is provided. The second device includes means for: sending a request from the second device to the first device to establish at least one tunnel between the first device and a third device, for forwarding at least one uplink packet from a fourth device and destined for the first device from the third device to the first device; receiving tunnel information about the at least one tunnel from the first device; providing the tunnel information to the third device for establishing the at least one tunnel; and providing identification information about the at least one uplink packet to be forwarded from the third device to the first device through the at least one tunnel to the third device.

[0014] In a ninth aspect, a third device is provided. The third device includes means for: acquiring, at the third device, tunnel information about at least one tunnel to be established between the third device and the first device from a second device; acquiring, from the second device, identification information about at least one uplink packet, the at least one uplink packet originating from a fourth device and destined for the first device, and the at least one uplink packet to be forwarded to the first device via the at least one tunnel and the third device; and, if it is determined that the uplink packet received from the fourth device includes the acquired identification information, forwarding the received uplink packet to the first device via one of the at least one tunnel.

[0015] In a tenth aspect, a computer-readable medium is provided, wherein the computer-readable medium includes program instructions, and when the program instructions are executed by at least one processor, the apparatus is caused to at least perform the method according to the fourth aspect.

[0016] In an eleventh aspect, a computer-readable medium is provided, wherein the computer-readable medium includes program instructions, and when the program instructions are executed by at least one processor, the computer-readable medium causes an apparatus to at least perform the method according to the fifth aspect.

[0017] In a twelfth aspect, a computer-readable medium is provided, wherein the computer-readable medium includes program instructions, and when the program instructions are executed by at least one processor, the apparatus at least executes the method according to the sixth aspect.

[0018] It should be understood that the 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

[0019] Some example embodiments will now be described with reference to the accompanying drawings, in which:

[0020] Figure 1 shows an example communication network in which example embodiments of the present disclosure may be implemented;

[0021] Figure 2 shows a signaling flow for rerouting packets according to some example embodiments of the present disclosure;

[0022] Figure 3 An example IAB protocol stack for at least one tunnel is shown according to some example embodiments of the present disclosure;

[0023] Figure 4 Another example IAB protocol stack for at least one tunnel according to some example embodiments of the present disclosure is shown;

[0024] Figure 5 shows a signaling flow for rerouting packets according to some other example embodiments of the present disclosure;

[0025] Figure 6 A flowchart illustrating a method implemented at a first device according to some example embodiments of the present disclosure is shown;

[0026] Figure 7 A flowchart illustrating a method implemented at a second device according to some example embodiments of the present disclosure is shown;

[0027] Figure 8 A flowchart illustrating a method implemented at a third device according to some example embodiments of the present disclosure is shown;

[0028] Figure 9 shows a simplified block diagram of an apparatus suitable for implementing an example embodiment of the present disclosure; and

[0029] Figure 10A block diagram of an example computer-readable medium is shown, according to some example embodiments of the present disclosure.

[0030] Throughout the drawings, the same or similar reference numerals denote the same or similar elements. DETAILED DESCRIPTION

[0031] The principles of the present disclosure will now be described with reference to some exemplary embodiments. It should be understood that these embodiments are described for illustrative purposes only and to help those skilled in the art understand and implement the present disclosure, without implying any limitation on the scope of the present disclosure. The embodiments described herein can be implemented in various ways different from those described below.

[0032] 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.

[0033] References in this disclosure to "one 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 exemplary embodiment, it is understood that it is 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.

[0034] It should be understood that although the terms "first" and "second" and the like 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. For example, without departing from the scope of the example embodiments, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element. As used herein, the term "and / or" includes any and all combinations of one or more of the listed terms.

[0035] The terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the example embodiments. Unless the context clearly indicates otherwise, as used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well. It will also be understood that the terms "comprise," "include," "have," "include," and / or "includes" when used herein specify the presence of stated features, elements, and / or components, but do not preclude the presence or addition of one or more other features, elements, components, and / or combinations thereof.

[0036] As used in this application, the term "circuitry" may refer to one or more or all of the following:

[0037] (a) hardware circuit implementation only (such as implementation in analog and / or digital circuits only) and

[0038] (b) a combination of hardware circuitry and software such as (as applicable):

[0039] (i) a combination of analog and / or digital hardware circuitry and software / firmware, and

[0040] (ii) any portion of a hardware processor with software (including a digital signal processor, software, and memory that work together to enable a device such as a mobile phone or server to perform various functions); and

[0041] (c) Hardware circuits and / or processors, such as a microprocessor or portion of a microprocessor, that require software (eg, firmware) to operate, but where software is not required for operation, the software may not be present.

[0042] This definition of circuitry applies to all uses of this term in this application, including in any claims. As another example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or a portion of a hardware circuit or processor and its (or its) accompanying software and / or firmware. The term circuitry also covers, for example and if applicable to a particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in a server, a cellular network device, or other computing or network device.

[0043] As used herein, the term "communication network" refers to a network that complies with any suitable communication standard, such as a fifth generation (5G) system, long term evolution (LTE), advanced LTE (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 terminal equipment and the network equipment in the communication network can be performed according to any suitable generation communication protocol, including but not limited to first generation (1G), second generation (2G), 2.5G, 2.75G, third generation (3G), fourth generation (4G), 4.5G, future fifth generation (5G) new radio (NR) communication protocol, and / or any other protocol currently known or to be developed in the future. The embodiments of the present disclosure can be applied to various communication systems. In view of the rapid development of communications, there are of course future types of communication technologies and systems, which can be used to embody the present disclosure. It should not be regarded as limiting the scope of the present disclosure to the above-mentioned systems / networks.

[0044] 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. Depending on the terminology and technology applied, a network device may refer to a base station (BS) or an access point (AP), for example, a Node B (Node B or NB), an evolved Node B (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 backhaul (IAB) node, an IAB-DU and an IAB-CU, a low power node such as a femto base station, a pico base station, a non-terrestrial network (NTN) or non-terrestrial network equipment, such as a satellite network equipment, a low earth orbit (LEO) satellite and a geosynchronous earth orbit (GEO) satellite, an aircraft network equipment, etc.

[0045] The term "terminal device" refers to any terminal device capable of wireless communication. As an example and not limitation, a terminal device may also be referred to as a communication device, user equipment (UE), subscriber station (SS), portable subscriber station, mobile station (MS) or access terminal (AT). Terminal devices may include, but are not limited to, mobile phones, cellular phones, smart phones, voice over IP (VoIP) phones, wireless local loop phones, tablet computers, wearable terminal devices, personal digital assistants (PDAs), portable computers, desktop computers, image capture terminal devices such as digital cameras, game terminal devices, music storage and playback devices, vehicle-mounted wireless terminal devices, wireless endpoints, mobile stations, laptop embedded devices (LEEs), laptop mounted devices (LMEs), USB dongles, smart devices, wireless client equipment (CPEs), Internet of Things (IoT) devices, watches or other wearable devices, head-mounted displays (HMDs), vehicles, targets, medical devices and applications (e.g., remote surgery), industrial devices 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" may be used interchangeably.

[0046] Figure 1 An example communication network 100 is shown in which example embodiments of the present disclosure may be implemented. Communication network 100 may include a first device 110, a second device 120, a third device 130, a fourth device 140, a parent device 150, a parent device 160, a child device 170, a grandchild device 180, and an end device 190.

[0047] exist Figure 1In the example shown in FIG. 1 , each of first device 110 and third device 130 communicates with second device 120. Fourth device 140 is connected to first device 110 via parent device 150. Terminal device 190 accesses communication network 100 via grandchild device 180. In other embodiments, communication network 100 may not include parent device 150 and parent device 160. In this way, fourth device 140 may be directly connected to first device 110.

[0048] In some embodiments, the communication network 100 may be implemented as an IAB network. In such an embodiment, each of the fourth device 140, the parent devices 150 and 160, the child device 170, and the grandchild device 180 may be implemented as an IAB node. In such an embodiment, the second device 120 may be implemented as an IAB-donor-CU, and each of the first device 110 and the third device 130 may be implemented as an IAB-donor-DU. Alternatively, the first device 110 may be implemented as an IAB-donor-CU-user plane, the second device 120 may be implemented as an IAB-donor-CU-control plane, and the IAB-donor-DU serving the parent device 150 may be implemented as an IAB-donor-DU. Figure 1 Not shown in the figure.

[0049] In an embodiment where each of the first device 110 and the third device 130 can be implemented as an IAB-donor-DU, the first device 110 and the third device 130 can communicate with different IAB-donor-CUs. For example, the first device 110 can communicate with the second device 120 serving as a source IAB-donor-CU, and the third device 130 can communicate with a target IAB-donor-CU ( Figure 1 In such an embodiment, the source IAB-donor-CU may communicate with the target IAB-donor-CU via an Xn interface.

[0050] In an embodiment where the communication network 100 is implemented as an IAB network, the IAB-Donor-CU and the IAB-Donor-DU may be collectively referred to as IAB-Donor. Figure 1 In the example of FIG, the second device 120, the first device 110, and the third device 130 may be collectively referred to as an IAB-donor 105. The IAB-donor 105 may be implemented as a gNB that terminates the wireless backhaul radio interface from one or more IAB nodes. The IAB-donor 105 has a wired / fiber connection to the core network. It should be understood that Figure 1By way of example, the IAB-donor 105 is shown to include two IAB-donor-DUs. In other embodiments, the IAB-donor 105 may include one IAB-donor-DU or more IAB-donor-DUs. Hereinafter, the CU of an IAB-donor is also referred to as a donor-CU, a donor central unit, or an IAB-donor-CU; and the DU of an IAB-donor is also referred to as a donor-DU, a donor distributed unit, or an IAB-donor-DU.

[0051] In an embodiment where the communication network 100 is implemented as an IAB network, an IAB node (e.g., each of devices 140, 150, 160, 170, and 180) may include a DU (IAB-DU) and a mobile terminal (IAB-MT), the IAB-MT maintaining a connection with one or more upstream nodes (e.g., using dual connectivity). Similar to a conventional user equipment, the MT of the IAB node may use radio resource control (RRC) signaling to provide radio link measurements of an alternative upstream node to its current serving gNB CU. Migration may be performed, for example, handover for the IAB-MT based on signal strength, signal quality, and other factors. Thus, a user equipment such as a UE may be connected to a mobile terminal. Figure 1 The IAB topology shown may be non-static. As a result of a migration, device 140 may change parent nodes from source parent node device 150 to target parent node device 160 after the migration. The IAB topology may change over time as radio conditions fluctuate and as IAB nodes move, being added or removed.

[0052] A CU (e.g., donor-CU) is a logical node that, in addition to those functions specifically assigned to a DU, may also include functions such as user data transfer, mobility control, radio access network sharing, positioning, session management, etc. (e.g., gNB functions). The CU can control the operation of the DU over the fronthaul (F1) interface. A DU is a logical node that can include a subset of the above functions (e.g., gNB functions).

[0053] The IAB-donor 105 can serve directly connected IAB nodes, such as devices 150 and 160 acting as IAB nodes, and IAB nodes linked via multiple wireless backhaul hops, such as devices 140, 170, and 180 acting as IAB nodes. The IAB-donor 105 can also serve directly connected terminal devices (not shown). An IAB node, such as devices 140, 150, 160, 170, and 180 acting as IAB nodes, can serve one or more terminal devices directly connected thereto. For example, Figure 1 As shown, device 180 can serve terminal device 190 that is directly connected to device 180.

[0054] It should be understood that the number of IAB nodes and terminal devices connected to the IAB nodes is for illustrative purposes only and does not imply any limitation. The IAB network can include any suitable number of IAB nodes and terminal devices suitable for implementing the example embodiments of the present disclosure. In other embodiments, the first device 110 can be implemented as other network devices. For example, when using an IPsec tunnel mode with a separate security gateway (SEG) to protect traffic between the second device 120 and the fourth device 140 (or child device 170, or grandchild device 180, etc.), the first device 110 can be implemented as an SEG.

[0055] It should be understood that Figure 1 The illustrated architecture of network 100 is described for illustrative purposes only and does not imply any limitation. Figure 1 The number of devices and their connections shown in the figure is for illustrative purposes only and does not imply any limitation. Network 100 may include any suitable number of devices suitable for implementing embodiments of the present disclosure. Although not shown, it should be understood that one or more additional devices may be deployed in network 100.

[0056] Communications in the communications network 100 may be implemented according to any suitable communications protocol, including but not limited to first generation (1G), second generation (2G), third generation (3G), fourth generation (4G), and fifth generation (5G) cellular communications protocols, wireless local area network communications protocols such as Institute of Electrical and Electronics Engineers (IEEE) 802.11, and / or any other protocols currently known or developed in the future. Furthermore, such communications may utilize any suitable wireless communications technology, including but not limited to code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), frequency division duplex (FDD), time division duplex (TDD), multiple input multiple output (MIMO), orthogonal frequency division multiplexing (OFDM), discrete Fourier transform spread OFDM (DFT-s-OFDM), and / or any other technology currently known or developed in the future.

[0057] In IAB communication, the donor-DU acts as the first-hop router for its descendant IAB nodes. For example, it allocates Internet Protocol (IP) addresses for IAB nodes from the donor-DU's address space, also known as the Internet Protocol (IP) addresses for IAB nodes anchored in the donor-DU. Based on security policies, the donor-DU can perform source IP filtering (also known as source IP address filtering, or filtering on IP source addresses) on IP packets received from its descendant IAB nodes. Specifically, the donor-DU can check whether the source IP address of a received IP packet is associated with the donor-DU. If a received IP packet includes a source IP address unrelated to the donor-DU, the received IP packet will be discarded.

[0058] During IAB migration, inter-donor-DU migration is performed when the target donor-DU is different from the source donor-DU. Intra-donor-CU inter-donor-DU migration occurs when the source and target donor-DUs belong to the same donor-CU. Inter-donor-CU migration occurs when the source and target donor-DUs belong to different donor-CUs or are connected to different donor-CUs.

[0059] In some embodiments, for example, due to a handover, the fourth device 140 may perform an inter-donor-DU migration procedure. In such embodiments, the fourth device 140 may be referred to as a migrating IAB node. Utilizing this migration procedure, the fourth device 140 may change the communication connection from the first device 110 to the third device 130 by migrating from the parent device 150 to the parent device 160. In such embodiments, the first device 110 may be referred to as a source IAB-donor-DU, the parent device 150 may be referred to as a source parent node of the fourth device 140, the third device 130 may be referred to as a target IAB-donor-DU, and the parent device 160 may be referred to as a target parent node of the fourth device 140.

[0060] In some embodiments, the migration may be a planned migration. For example, handover preparation is performed for the migrating IAB node. Alternatively, the migration may be an unplanned migration. For example, the migrating IAB node declares a radio link failure (RLF) with the source parent cell / node and then connects to the target parent cell / node.

[0061] For UL routing, before migration, the UL routing identification (ID) and source IP address of the UL packet are associated with the source donor-DU. The source IP address of the IP header in the UL packet originating from the IAB node is the IP address of the IAB, which is anchored in the source donor-DU. For example, the UL routing ID of the UL packet may include the BAP address of the source donor-DU, and the source IP address of the UL packet is the IP address of the IAB node allocated from the address space of the source donor-DU. After migration, the migrating IAB node and the descendant IAB nodes will use the new UL routing ID and new IP address associated with the target donor-DU of the UL routing. The source IP address of the IP header in the UL packet is the IP address of the IAB node, which is anchored in the target donor-DU. For example, the UL routing ID of the UL packet may include the BAP address of the target donor-DU, and the source IP address of the UL packet is the IP address of the IAB node allocated from the address space of the target donor-DU. Figure 1In the example shown in FIG, before migration, the UL routing ID and source IP address of UL packets sent by fourth device 140 (or by child device 170, or by grandchild device 180, etc.) are associated with first device 110. After migration, fourth device 140, child device 170, grandchild device 180, etc. will use a new UL routing ID and a new IP address associated with third device 130 for new UL packets sent to second device 120.

[0062] During migration, the migrating IAB node and its descendant IAB nodes may have one or more buffered UL packets received from their respective child IAB nodes. The UL packets include the UL routing ID and IP address associated with the source donor-DU. After migration, if the buffered UL packets are sent to the target donor-DU, they will be discarded due to source IP filtering (also known as source IP address filtering, or filtering on the IP source address). This will result in UL packet loss.

[0063] Some options can be considered to avoid UL packet loss. For example, in Option 1, the IAB-Donor-CU can configure a target IAB-Donor-DU with an IP address related to the source Donor-DU for source IP filtering in the target IAB-Donor-DU. However, Option 1 may not work. This option only avoids source IP filtering in the target Donor-DU; however, due to security policies, the transmitting network nodes between the target Donor-DU and the target Donor-CU may still implement source IP filtering and drop UL packets. For example, the IP router between the second device 120 and the third device 130 may also perform source IP filtering, which may lead to UL packet loss.

[0064] For another example, in Option 2, source IP filtering in the target IAB-Donor-DU can be suspended or disabled. However, this option may cause security issues because source IP filtering, which was introduced to ensure security, is disabled. This is undesirable considering that the transport network may be managed by different operators and source IP filtering may be part of their security policies.

[0065] For another example, in Option 3, rerouting is allowed only in a subset of configured IAB-Donor-DUs. Option 3 can be considered a variation of Option 2, where source IP filtering is suspended or disabled in the subset. Similar security issues exist.

[0066] According to some example embodiments of the present disclosure, a scheme for rerouting packets in a communication network is provided. In this scheme, at least one tunnel is established between a first device and a third device. If the third device determines that an uplink packet received from a fourth device is destined for the first device (e.g., based on identification information about at least one uplink packet), the third device forwards the received uplink packet to the first device via one of the at least one tunnel. This scheme can avoid uplink packet loss, for example, during donor-DU migration. In addition, this scheme does not violate security policies in the transport network and the IAB-donor-DU. In other words, source IP filtering can be normally applied to the rerouted packets.

[0067] Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0068] Now refer to Figure 2 , which shows a signaling flow 200 for packet rerouting according to some example embodiments of the present disclosure. For the purpose of discussion, reference will be made to Figure 1 Describe the signaling flow 200. The signaling flow 200 may involve Figure 1 In the embodiment, a first device 110, a second device 120, a third device 130, a fourth device 140, a parent device 150 and a parent device 160 are shown.

[0069] The second device 120 sends 205 to the first device 110 a request for establishing at least one tunnel between the first device 110 and the third device 130. Accordingly, the first device 110 receives 210 the request from the second device 120.

[0070] The second device 120 may send the request in any appropriate scenario. For example, in the case of a planned migration, the second device 120 may send the request during handover preparation of the migrating IAB (such as the fourth device 140). Alternatively, in the case of an unplanned migration, the second device 120 may send the request during reestablishment of the migrating IAB. Alternatively, when a target IAB-donor-DU (such as the third device 130) receives an UL Backhaul Adaptation Protocol (BAP) packet related to a source donor-DU (such as the first device 110), the second device 120 may send the request based on the request from the target donor-DU.

[0071] In some example embodiments, the request may indicate a format of the at least one UL packet to be forwarded to first device 110. For example, the request may indicate whether the UL packet to be forwarded will include a BAP header. In some other embodiments, the format of the at least one UL packet to be forwarded to first device 110 is preconfigured or predefined, and thus the format indication is not included in the request.

[0072] In some example embodiments, the request may additionally or alternatively indicate the number of the at least one tunnel to be established when multiple tunnels are to be established.

[0073] After receiving the request, the first device 110 sends 215 to the second device 120 tunnel information about at least one tunnel to be established between the first device 110 and the third device 130. Accordingly, the second device 120 receives 220 the tunnel information from the first device 110.

[0074] In some example embodiments, the at least one tunnel may include a first tunnel.In such embodiments, the tunnel information may include at least one of an IP address of the first device 110 or an identification (ID) of a tunnel endpoint associated with the first tunnel.

[0075] In some example embodiments, the tunnel information may additionally or alternatively include a format of at least one uplink packet to be forwarded to first device 110 via the tunnel between first device 110 and third device 130. For example, where the request to establish the at least one tunnel does not indicate a format of the at least one uplink packet, the tunnel information may include a format of the at least one uplink packet acceptable to first device 110. For example, the format may indicate whether the uplink packet to be forwarded should include a BAP header. In some embodiments, the format of the at least one UL packet to be forwarded is preconfigured or predefined, and thus the format indication is not included in the tunnel information.

[0076] Continue to refer Figure 2 Upon receiving the tunnel information, the second device 120 provides 225 the tunnel information to the third device 130 for establishing at least one tunnel. In one example embodiment, the second device 120 receives the format of at least one uplink packet from the first device 110 and provides it to the third device 130. In another example embodiment, the second device 120 may determine the format of at least one uplink packet to be forwarded to the first device 110 via the tunnel between the first device 110 and the third device 130, and provide it to the first device 110 and the third device 130 in a request. Accordingly, the third device 130 obtains 230 the tunnel information from the second device 120.

[0077] In some example embodiments, the second device 120 may send the tunnel information directly to the third device 130 without going through another target donor-CU as mentioned in the following paragraphs.

[0078] As described above, in some example embodiments, each of the first device 110 and the third device 130 may be implemented as an IAB-donor-DU. In some embodiments, the first device 110 and the third device 130 may communicate with or be connected to different IAB-donor-CUs. In such embodiments, for example, in an Xn Application Protocol (XnAP) handover preparation process for planned migration or in an XnAP UE context acquisition process for unplanned migration, the second device 120 may first send tunnel information to a target donor-CU ( Figure 2 ). The target donor-CU then forwards the tunnel information to third device 130. That is, in some embodiments, at 225, second device 120 may provide the tunnel information to third device 130 via another device (eg, the target donor-CU).

[0079] In addition to the tunnel information, second device 120 also provides 235 identification information to third device 130, the identification information relating to at least one uplink packet from fourth device 140 that is destined for first device 110 and is to be forwarded to first device 110 via at least one tunnel and third device 130. The identification information is associated with one or more tunnels. Similar to the tunnel information, in some example embodiments, second device 120 may send the tunnel information directly to third device 130. Alternatively, second device 120 may provide the identification information to third device 130 via a target donor-CU in communication with third device 130. Accordingly, third device 130 obtains 240 the identification information from second device 120.

[0080] In some example embodiments, the identification information may include at least one identifier associated with first device 110. For example, the identification information may include at least one of a source IP address or a destination IP address. In this case, the source IP address is the IP address of an IAB node allocated from the address space of first device 110. Alternatively, the destination IP address is the IP address of first device 110, or the IP address of second device 120 or a security gateway. For another example, the identification information may include at least one of a BAP address or a BAP routing ID. In this case, the BAP address is the same as the BAP address of first device 110. The BAP routing ID is a UL routing ID and includes the BAP address of first device 110. As another example, at least one uplink packet may include a flow label or a differentiated services code point (DSCP) and at least one of an IP address, a BAP address, or a BAP routing ID. In this case, the flow label and / or DSCP are used to further distinguish UL packets that share the same IP address, BAP address, or BAP routing ID associated with first device 110, but have different flow labels and / or DSCPs.

[0081] After acquiring the tunnel and identification information, the third device 130 establishes 245 at least one tunnel with the first device 110 .

[0082] In some example embodiments, signaling flow 200 may be performed during an IAB migration process of fourth device 140 (also referred to as migrating IAB node 140). Prior to the IAB migration, downlink (DL) packets (e.g., F1-U traffic) are routed to fourth device 140 (and, in some embodiments, its descendant IAB nodes, e.g., child IAB 170) via parent device 150 and first device 110, and uplink (UL) packets (e.g., F1-U traffic) are routed from fourth device 140 (and, in some embodiments, its descendant IAB nodes, e.g., child IAB node 170) to second device 120. After the IAB migration, downlink (DL) packets (e.g., F1-U traffic) are routed to the fourth device 140 (and in some embodiments, its descendant IAB nodes, such as the child IAB node 170) via the parent device 160 and the third device 130, and uplink (UL) packets (e.g., F1-U traffic) are routed from the fourth device 140 (and in some embodiments, its descendant IAB nodes, such as the child IAB node 170) to the second device 120.

[0083] In an embodiment in which signaling flow 200 is performed during an IAB migration process of fourth device 140, fourth device 140 connects 250 to a target cell. For example, fourth device 140 may connect to a cell of parent device 160 under third device 130 acting as a target donor-DU. Alternatively, fourth device 140 may connect to a cell of third device 130 acting as a target donor-DU, or may connect to a cell of an IAB node under third device 130 acting as a target donor-DU.

[0084] After migrating to the target parent device 160, the fourth device 140 forwards 252 the UL packet to the third device 130 via the target parent device 160. Thus, the third device 130 receives 254 the UL packet from the fourth device 140. The UL packet forwarded by the fourth device 140 may originate from the fourth device 140, or from a descendant IAB node, e.g., Figure 1 The sub-device 170 shown, Figure 1 The grandchild nodes shown are 180 and so on.

[0085] In some example embodiments, the UL packet may include a UL packet destined for first device 110 and to be forwarded to first device 110 via at least one tunnel and third device 130. For example, the UL packet may be a packet buffered prior to migration. Alternatively, the UL packet may include a UL packet destined for third device 130.

[0086] In some example embodiments, at least one uplink packet destined for first device 110 may include at least one identifier associated with first device 110. For example, the at least one uplink packet may include at least one of a source IP address or a destination IP address. For another example, the at least one uplink packet may include at least one of a BAP address or a BAP routing ID. As another example, the at least one uplink packet may include at least one of a flow label or a Differentiated Services Code Point (DSCP).

[0087] After receiving the UL packet, the third device 130 determines 260 whether the UL packet includes identification information that matches the identification information obtained from the second device 120. If the UL packet includes the identification information, the third device 130 forwards 270 the UL packet to the first device 110 via one of the at least one tunnels. In other words, if the UL packet includes one or more identifications associated with the first device 110, the third device 130 forwards the UL packet to the first device 110. UL packets that include one or more identifications associated with the first device 110 are considered buffered packets. Therefore, the first device 110 receives 272 the UL packet.

[0088] On the other hand, if the UL packet does not include the identification information obtained from the second device 120, the third device 130 forwards 278 the UL packet to the second device 120. In other words, if the UL packet does not include the identification associated with the first device 110, the third device 130 forwards the UL packet to the second device 120. A UL packet that does not include the identification associated with the first device 110 is also considered a new packet. Therefore, the second device 120 receives 280 the UL packet.

[0089] At least one tunnel may be configured in various ways. For purposes of illustration and not limitation, some example options for configuration are provided below.

[0090] Option 1: All UL packets originating from one or more IAB nodes share one tunnel. For example, Figure 1 In the example of FIG, all UL packets originating from fourth device 140 share one tunnel, and all UL packets originating from child device 170 and grandchild device 180 share another tunnel. Alternatively, all UL packets originating from fourth device 140, child device 170, and grandchild device 180 share one tunnel.

[0091] In Option 1, the identification information obtained in the third device 130 may include one or more source IP addresses associated with the first device 110, for example, one or more IP addresses assigned to the fourth device 140 (and, in some embodiments, its descendant IAB nodes, such as the child device 170), and the IP address is anchored in the first device 110, which means that downlink (DL) IP packets using the IP address as the destination IP address in the IP header will be routed via the first device 110. When the fourth device 140 (and, in some embodiments, its descendant IAB nodes, such as the child device 170) transmits an UL IP packet (e.g., an F1-U packet), the fourth device 140 (and, in some embodiments, its descendant IAB nodes, such as the child device 170) uses its IP address as the source IP address field in the IP header of the UL packet. The third device 130 determines the applicable UL packet to be forwarded on the at least one tunnel and one of the associated tunnels based on the source IP address field in the IP header of the received UL packet and the obtained identification information. For example, when the third device 130 determines that the IP address included in the source IP address field in the received uplink packet matches the source IP address in the acquired identification information, the third device 130 forwards the received UL packet to the first device 110 via one of the at least one tunnels.

[0092] Option 2: All UL packets destined for the first device 110 share one tunnel. In Option 2, the identification information obtained in the third device 130 may include one or more IP addresses related to the first device, for example, one or more IP addresses of the second device 120 or the security gateway, and the IP addresses may be routed via the first device 110 (for example, UL packets destined for the second device 120 or the security gateway are routed via the first device 110). In another example embodiment, the identification information obtained in the third device 130 may include one or more UL routing IDs related to the first device 110, for example, one or more UL routing IDs assigned to the fourth device 140 and a routing ID related to the first device 110. The UL routing ID includes the BAP address of the first device 110. In yet another example, the identification information obtained in the third device 130 may include one or more BAP addresses related to the first device 110, for example, one or more BAP addresses of the first device 110. The third device 130 determines, based on the destination IP address field or the UL routing ID or the BAP address in the IP header of the received UL packet and the acquired identification information, an applicable UL packet to be forwarded through the at least one tunnel and one of the related tunnels. For example, when the third device 130 determines that the IP address included in the destination IP address field of the received uplink packet matches the destination IP address in the acquired identification information, and / or the UL routing ID included in the BAP header of the received uplink packet matches the UL routing ID in the acquired identification information, and / or the BAP address included in the received uplink packet matches the BAP address in the acquired identification information, the third device 130 forwards the received UL packet to the first device 110 via the tunnel.

[0093] Option 3: All UL packets destined for the first device 110 and sharing one or more DSCPs share one tunnel. In Option 3, the identification information obtained in the third device 130 may include one or more BAP addresses related to the first device 110, and one or more DSCP values. The third device 130 determines the applicable UL packet to be forwarded on at least one tunnel and one of the related tunnels based on the BAP address in the received UL packet and the obtained identification information. For example, when the third device 130 determines that the BAP address included in the received uplink packet matches the BAP address in the obtained identification information, and the DSCP in the IP header of the received uplink packet matches the DSCP in the obtained identification information, the third device 130 forwards the received UL packet to the first device 110 via the tunnel.

[0094] Option 4: All UL packets destined for the first device 110 and sharing one or more flow labels share one tunnel. In Option 4, the identification information obtained in the third device 130 may include one or more BAP addresses related to the first device 110, and one or more flow label values. The third device 130 determines the applicable UL packet to be forwarded on at least one tunnel and one of the related tunnels based on the BAP address and flow label or DSCP in the received UL packet and the obtained identification information. For example, when the third device 130 determines that the BAP address included in the received uplink packet matches the BAP address in the obtained identification information, and the flow label in the IP header of the received uplink packet matches the flow label in the obtained identification information, the third device 130 forwards the received UL packet to the first device 110 via the tunnel.

[0095] Option 5: All UL packets using one or more specific routing IDs share one tunnel. In Option 5, the identification information obtained in the third device 130 may include one or more UL routing IDs related to the first device 110, for example, one or more UL routing IDs assigned to the fourth device 140 and a routing ID related to the first device 110. The third device 130 determines the applicable UL packet to be forwarded on at least one tunnel and one of the related tunnels based on the UL routing ID in the received UL packet and the obtained identification information. For example, when the third device 130 determines that the routing identifier included in the received uplink packet matches the UL routing ID in the obtained identification information, the third device 130 forwards the received UL packet to the first device 110 via the tunnel.

[0096] It is understood that the identification information obtained in the third device 130 may include any combination of the source IP address, destination IP address, UL routing ID, BAP address, DSCP, and flow label for each tunnel of at least one tunnel. The applicable UL packet may be identified by any combination of the source IP address, destination IP address, UL routing ID, BAP address, DSCP, and flow label. It is also understood that the information obtained in the third device 130 may include identification information related to the first device 110 and / or descendant IAB nodes (e.g., child device 170, etc.), and thus the obtained identification information may be applicable to UL packets originating from descendant IAB nodes (e.g., child device 170, etc.). For example, the obtained identification information may include one or more IP addresses assigned to a descendant IAB node (e.g., child IAB 170) of the fourth device 140, and the IP addresses are anchored in the first device 110. When the descendant IAB node (eg, child IAB 170) of the fourth device 140 transmits a UL IP packet (eg, F1-U packet), the descendant IAB node (eg, child IAB 170) of the fourth device 140 uses the IP address as the source IP address field in the IP header of the UL packet.

[0097] In some example embodiments, upon receiving 272 an UL packet from third device 130, first device 110 determines whether the at least one uplink packet is destined for first device 110 based on at least one BAP header included in the received at least one uplink packet. If the at least one uplink packet is destined for first device 110, first device 110 removes the at least one BAP header from the at least one uplink packet and forwards 274 the at least one uplink packet without the at least one BAP header to second device 120 or a security gateway. If the at least one uplink packet does not include a BAP header, first device 110 forwards 274 the at least one uplink packet to second device 120 or a security gateway. Consequently, second device 120 receives 276 the at least one uplink packet.

[0098] In some example embodiments, second device 120 may instruct the third device whether to keep or remove the BAP header in uplink packets received from fourth device 140, eg, via the indicated packet format.

[0099] In some example embodiments, the at least one established tunnel may be released after the migration is complete. For example, second device 120 may send a first request to release the at least one tunnel to first device 110, and send a second request to release the at least one tunnel to third device 130. Upon receiving the first request, first device 110 releases the at least one tunnel. Upon receiving the second request, third device 130 releases the at least one tunnel.

[0100] Alternatively, the at least one tunnel can be retained and reused for another IAB node. For example, if the source donor-DU assigns the IP address to a different IAB node, the IAB node can later perform the same migration. This can occur for a mobile IAB used on a train. Alternatively, in some embodiments, the at least one tunnel can be released based on a timer.

[0101] Figure 3 An example IAB protocol stack 300 for at least one tunnel is shown according to some example embodiments of the present disclosure. Figure 3 In the example of FIG, second device 120 may be implemented as an IAB-donor-CU, first device 110 and third device 130 may each be implemented as an IAB-donor-DU, and fourth device 140, parent device 160, and child device 170 may each be implemented as an IAB node. Each of fourth device 140, parent device 160, and child device 170 may include an IAB-DU and an IAB-MT.

[0102] As shown in the figure, the sub-device 170 supports the General Packet Radio System (GPRS) Tunneling Protocol User Plane (GTP-U) protocol, User Datagram Protocol (UDP), and IP for communication with the second device 120. The sub-device 170 also supports BAP, Radio Link Control (RLC) protocol, Media Access Control (MAC) protocol, and Physical Layer (PHY) protocol for communication with the fourth device 140. The fourth device 140 supports BAP, RLC, MAC, and PHY protocols for communication with the target parent device 160. The third device 130 supports BAP, RLC, MAC, and PHY protocols for communication with the target parent device 160, and supports BAP, GTP-U, UDP, and IP protocols for communication with the first device 110. The first device 110 supports the IP protocol for communication with the sub-device 170, supports BAP, GTP-U, UDP, and IP protocols for communication with the third device 130, and supports IP, Layer 1 (L1) / Layer 2 (L2) protocols for communication with the second device 120.

[0103] A General Packet Radio System (GPRS) Tunneling Protocol User Plane (GTP-U) tunnel is established between the first device 110 and the third device 130. In other exemplary embodiments, other tunneling protocols, such as the Generic Routing Encapsulation (GRE) protocol or IP in IP tunneling protocols (e.g., Mobile IP (MIP) or Proxy Mobile IP (PMIP)), may also be used to establish the tunnel. As shown, the BAP layer terminates in the first device 110. In this case, UL packets forwarded from the third device 130 to the first device 110 include a BAP header.

[0104] Figure 4 Another example IAB protocol stack 400 for at least one tunnel is shown according to some example embodiments of the present disclosure. Figure 3 In the example, Figure 4 In the example, the second device 120 may be implemented as an IAB-donor-CU, and each of the first device 110 and the third device 130 may be implemented as an IAB-donor-DU, and each of the fourth device 140, the parent device 160, and the child device 170 may be implemented as an IAB node.

[0105] The structure of the IAB protocol stack 400 is similar to that of the IAB protocol stack 300. For example, a GTP-U tunnel is established between the first device 110 and the third device 130. In other exemplary embodiments, other tunnel protocols may also be used to establish a tunnel. Figure 3 The examples in Figure 4 In the example of , the BAP layer is terminated in the third apparatus 130. In this case, the UL packet forwarded from the third device 130 to the first device 110 does not include a BAP header.

[0106] Now refer to Figure 5 , which shows a signaling flow 500 for rerouting packets according to some other example embodiments of the present disclosure. For the purpose of discussion, reference will be made to Figure 1 Describe the signaling flow 500. The signaling flow 500 may involve Figure 1 1 , a first device 110, a second device 120, a third device 130, a fourth device 140, a parent device 150, a parent device 160, a child device 170, a grandchild device 180, and a terminal device 190 are described. In some example embodiments, signaling flow 500 may be performed during an IAB migration process for fourth device 140 (also referred to as fourth device 140). Therefore, signaling flow 500 will be described in conjunction with the IAB migration process. However, signaling flow 500 may be performed independently of the IAB migration process.

[0107] The fourth device 140 sends 501 a measurement report message to the parent device 150. The report is based on the measurement configuration in the fourth device 140 previously received from the second device 120.

[0108] After receiving 502 the measurement report message, the parent device 150 sends 503 a UL RRC MESSAGE TRANSFER message to the second device 120 to transmit the received measurement report.

[0109] After receiving the UL RRC MESSAGE TRANSFER message 504, the second device 120 sends 505 a UE CONTEXT SETUP REQUEST message to the parent device 160 to create a UE context for the fourth device 140 and establish one or more bearers. These bearers can be used by the fourth device 140 for its own signaling and, optionally, for data traffic.

[0110] After receiving 506 the UE CONTEXT SETUP REQUEST message, the parent device 160 responds to the second device 120 with a UE CONTEXT SETUP RESPONSE message 507. Accordingly, the second device 120 receives 508 the UE CONTEXT SETUP RESPONSE message.

[0111] After the second device 120 decides to perform the IAB node migration procedure, for example, after receiving the UE CONTEXT SETUP RESPONSE message, the second device 120 may initiate a process 509 to establish at least one tunnel between the first device 110 and the third device 130. For example, Figure 2 508, for example, it may be performed after 504.

[0112] The second device 120 sends 510 a UE CONTEXT MODIFICATION REQUEST message to the parent device 150, which includes the generated RRCReconfiguration message. The RRCReconfiguration message includes a default backhaul (BH) radio link control (RLC) channel and a default BAP routing ID configuration for UL F1 control plane interface (F1-C) / non-F1 traffic mapping on the target path. It may include additional BHRLC channels. The action may also include the allocation of a transport network layer (TNL) address routable via the third device 130. The new TNL address may be included in the RRC reconfiguration message as a replacement for the TNL address routable via the first device 110. In the case of using Internet Protocol Security (IPsec) tunnel mode to protect F1 and non-F1 traffic, the allocated TNL address is an external IP address. If the source and target paths use the same IAB-Donor-DU, TNL address replacement is unnecessary. The transmission action indicator in the UE CONTEXT MODIFICATION REQUEST message indicates to stop data transmission to the fourth device 140 .

[0113] After receiving 511 the UE CONTEXT MODIFICATION REQUEST message, the parent device 150 forwards 512 the received RRC Reconfiguration message to the fourth device 140. Accordingly, the fourth device 140 receives 513 the forwarded RRC Reconfiguration message.

[0114] The parent device 150 responds 514 to the second device 120 with a UE CONTEXT MODIFICATION RESPONSE message. Accordingly, the second device 120 receives 515 the UE CONTEXT MODIFICATION RESPONSE message.

[0115] A random access procedure 516 is performed at the fourth device 140 .

[0116] The fourth device 140 responds 517 to the parent device 160 with an RRCReconfigurationComplete message.

[0117] Upon receiving 518 the RRCReconfigurationComplete message, the parent device 160 sends 519 a UL RRC MESSAGE TRANSFER message to the second device 120 to transfer the received RRCReconfigurationComplete message. Accordingly, the second device 120 receives 520 the UL RRC MESSAGE TRANSFER message.

[0118] The second device 120 configures 521 a BH RLC channel and a BAP sublayer routing entry on a target path between the fourth device 140 and the third device 130 , and configures a DL mapping on the third device 130 for the target path of the fourth device 140 .

[0119] After the fourth device 140 connects to the cell of the parent device 160, for example, after performing action 521, the third device 130 begins forwarding 270 the buffered UL packets to the first device 110 via the tunnel. The packets forwarded to the first device can be BAP PDUs (or contain BAP headers) or IP packets. After receiving 272 the buffered UL packets, the first device 110 can forward 522 the buffered UL packets to the second device 120. Accordingly, the second device 120 receives 523 the buffered UL packets.

[0120] The F1-C connection is switched to use the new TNL address of the fourth device 140, and the second device 120 updates the UL BH information associated with each GTP tunnel to the fourth device 140. In other words, redirection 524 of the F1 association of the fourth device 140 to the new TNL address is performed.

[0121] Second device 120 configures 525 a BH RLC channel and a BAP sublayer routing entry on a target path between sub-device 170 and third device 130 , and configures a DL mapping on third device 130 for the target path of sub-device 170 .

[0122] The F1-C connection is switched to use the new TNL address of sub-device 170, and second device 120 updates the UL BH information associated with each GTP tunnel to sub-device 170. In other words, redirection 526 of the F1 association of sub-device 170 to the new TNL address is performed.

[0123] Second device 120 configures 527 a BH RLC channel and a BAP sublayer routing entry on a target path between grandchild device 180 and third device 130 , and configures a DL mapping on third device 130 for the target path of grandchild device 180 .

[0124] The F1-C connection is switched to use the new TNL address of grandchild device 180, and second device 120 updates the UL BH information associated with each GTP tunnel to grandchild device 180. In other words, a redirection 528 of grandchild device 180's F1 association to the new TNL address is performed.

[0125] After the migration is complete, for example after act 528 , the second device 120 may initiate a tunnel release 529 .

[0126] It should be understood that Figure 5 The signaling flows in are provided as examples only and not by way of limitation. In some embodiments, similar mechanisms for packet rerouting may be used in different processes with different signaling flows.

[0127] Figure 6 FIG. 6 is a flow chart illustrating an example method 600 implemented at a first device according to some example embodiments of the present disclosure. For the purpose of discussion, reference will be made to Figure 1 The method 600 is described from the perspective of the first device 110 .

[0128] In block 610 , the first device 110 receives a request from the second device 120 in communication with the first device 110 to establish at least one tunnel between the first device 110 and a third device 130 .

[0129] In some example embodiments, the request may indicate a format of at least one UL packet to be forwarded to first device 110. For example, the request may indicate whether the UL packet is to include a BAP header.

[0130] In some example embodiments, the request may additionally or alternatively indicate a number of the at least one tunnel to be established.

[0131] In block 620 , the first device 110 transmits tunnel information about at least one tunnel to be established between the first device 110 and the third device 130 to the second device 120 .

[0132] In some example embodiments, the at least one tunnel may include a first tunnel. In such embodiments, the tunnel information may include at least one of an IP address of the first device 110 or an identification (ID) of a tunnel endpoint associated with the first tunnel.

[0133] In some example embodiments, the tunnel information may additionally or alternatively include a format of the at least one uplink packet to be forwarded to first device 110. For example, where the request to establish the at least one tunnel does not indicate a format of the at least one uplink packet, the tunnel information may include the format of the at least one uplink packet.

[0134] At block 630, the first device 110 receives at least one uplink packet destined for the first device 110 from the fourth device 140 via the third device 130 and the at least one tunnel. The received at least one uplink packet may be a BAPPDU (or contain a BAP header) or an IP packet.

[0135] In some example embodiments, at least one uplink packet destined for first device 110 may include at least one identifier associated with first device 110. For example, the at least one uplink packet may include at least one of a source IP address or a destination IP address. For another example, the at least one uplink packet may include at least one of a BAP address or a BAP routing ID. As another example, the at least one uplink packet may include at least one of a flow label or a Differentiated Services Code Point (DSCP).

[0136] In some example embodiments, upon receiving the UL packet from the third device 130, the first device 110 determines whether the uplink packet includes a BAP header.

[0137] In some embodiments, if the uplink packet includes a BAP header, the first device 110 determines, based on the BAP header, whether the uplink packet is destined for the first device 110. If the uplink packet is destined for the first device 110, the first device 110 removes the BAP header from the uplink packet and forwards the uplink packet without the BAP header to the second device 120 or the security gateway.

[0138] In some embodiments, the uplink packet does not include a BAP header, and the first device 110 forwards the uplink packet to the second device 120 or a security gateway.

[0139] Figure 7 FIG. 7 is a flow chart illustrating an example method 700 implemented at a second device according to some example embodiments of the present disclosure. For the purpose of discussion, reference will be made to Figure 1 The method 700 is described from the perspective of the second device 120 .

[0140] In box 710, the second device 120 sends a request to the first device 110 communicating with the second device 120 to establish at least one tunnel between the first device 110 and the third device 130 for forwarding at least one uplink packet from the fourth device 140 and destined for the first device 110 from the third device 130 to the first device 110.

[0141] The second device 120 may send the request in any appropriate circumstances. For example, in the case of a planned migration, the second device 120 may send the request during handover preparation of the IAB undergoing migration (such as the fourth device 140). Alternatively, in the case of an unplanned migration, the second device 120 may send the request during reestablishment of the IAB undergoing migration. Alternatively, when the target IAB-donor-DU (such as the third device 130) receives an UL Backhaul Adaptation Protocol (BAP) packet involving the source donor-DU (such as the first device 110), the second device 120 may send the request based on the request from the target donor-DU. In some embodiments, the second device 120 may send the request for establishing a tunnel in advance before detecting that a handover or reestablishment is required.

[0142] In some example embodiments, the request may indicate a format of at least one UL packet targeted to first device 110. For example, the request may indicate whether the UL packet is to include a BAP header.

[0143] In some example embodiments, the request may additionally or alternatively indicate a number of the at least one tunnel to be established.

[0144] In block 720 , the second device 120 receives tunnel information about the at least one tunnel from the first device 110 .

[0145] In some example embodiments, the at least one tunnel may include a first tunnel.In such embodiments, the tunnel information may include at least one of an IP address of the first device 110 or an identification (ID) of a tunnel endpoint associated with the first tunnel.

[0146] In some example embodiments, the tunnel information may additionally or alternatively include a format of the at least one uplink packet to be forwarded to first device 110. For example, where the request to establish the at least one tunnel does not indicate a format of the at least one uplink packet, the tunnel information may include the format of the at least one uplink packet.

[0147] At block 730 , the second device 120 provides tunnel information to the third device 130 for establishment of at least one tunnel.

[0148] In some example embodiments, the second device 120 may send the tunnel information directly to the third device 130 .

[0149] In some example embodiments, each of the first device 110 and the third device 130 may be implemented as an IAB-donor-DU, and the first device 110 and the third device 130 may communicate with different IAB-donor-CUs.

[0150] In such an embodiment, for example, in an XnAP handover preparation process for planned migration or in an XnAP UE context acquisition process for unplanned migration, the second device 120 may first send tunnel information via an Xn interface to a target donor-CU in communication with the third device 130. The target donor-CU then forwards the tunnel information to the third device 130.

[0151] At block 740 , the second device 120 provides, to the third device 130 , identification information regarding at least one uplink packet to be forwarded from the third device 130 to the first device 110 through the at least one tunnel.

[0152] Similar to the tunnel information, in some example embodiments, second device 120 may send the identification information directly to third device 130. Alternatively, second device 120 may provide the identification information to third device 130 via a target donor-CU in communication with third device 130.

[0153] Figure 8 FIG. 8 is a flow chart illustrating an example method 800 implemented at a third device according to some example embodiments of the present disclosure. For discussion purposes, reference will be made to FIG. Figure 1 The method 800 is described from the perspective of the third device 130 .

[0154] In block 810 , the third device 130 acquires tunnel information about at least one tunnel to be established between the third device 130 and the first device 110 from the second device 120 .

[0155] In some example embodiments, the at least one tunnel may include a first tunnel.In such embodiments, the tunnel information may include at least one of an IP address of the first device 110 or an identification (ID) of a tunnel endpoint associated with the first tunnel.

[0156] In some example embodiments, the tunnel information may additionally or alternatively include a format of the at least one uplink packet to be forwarded to the first device 110 .

[0157] In some example embodiments, third device 130 may receive tunnel information directly from second device 120 .

[0158] In some example embodiments, each of first device 110 and third device 130 may be implemented as an IAB-donor-DU, and first device 110 and third device 130 may communicate with and / or be controlled by different IAB-donor-CUs. In such an embodiment, for example, during an XnAP handover preparation process for planned migration or during an XnAP UE context acquisition process for unplanned migration, second device 120 may first send tunnel information to a target donor-CU in communication with third device 130 via an Xn interface. The target donor-CU then forwards the tunnel information to third device 130. Thus, third device 130 may receive the tunnel information forwarded from the target donor-CU.

[0159] In box 820, the third device 130 obtains identification information about at least one uplink packet from the second device 120, which is from the fourth device 140 and is targeted at the first device 110, and the at least one uplink packet will be forwarded to the first device 110 via at least one tunnel and the third device 130.

[0160] Similar to the tunnel information, in some example embodiments, third device 130 may receive the identification information directly from second device 120. Alternatively, second device 120 may provide the identification information to third device 130 via a target donor-CU in communication with third device 130. Thus, third device 130 receives the identification information forwarded from the target donor-CU.

[0161] In some example embodiments, the identification information may include at least one identifier associated with first device 110. For example, the identification information may include at least one of a source IP address or a destination IP address. As another example, the identification information may include at least one of a BAP address or a BAP routing ID. As another example, at least one uplink packet may include at least one of a flow label or a DSCP.

[0162] After receiving the UL packet, at block 830, the third device 130 determines whether the UL packet includes identification information that matches the identification information obtained from the second device 120. The identification information is associated with each tunnel. Therefore, when it is determined that the UL packet includes identification information that matches the identification information obtained from the second device 120, the third device 130 can determine that the UL packet is an applicable packet and can also determine the relevant tunnel (if more than one tunnel is established). If the UL packet includes identification information, then at block 840, the third device 130 forwards the UL packet to the first device 110 via one of the at least one tunnels. In other words, if the UL packet includes one or more identifications associated with the first device 110, the third device 130 forwards the UL packet to the first device 110.

[0163] On the other hand, if the UL packet does not include the identification information, the third device 130 may forward the UL packet to the second device 120. In other words, if the UL packet does not include the identification associated with the first device 110, the third device 130 may forward the UL packet to the second device 120.

[0164] In some example embodiments, third device 130 may determine an applicable UL packet to be forwarded to first device 110 based on whether the IP address included in the source IP address field in the received uplink packet matches the source IP address in the acquired identification information. In such an embodiment, if the IP address included in the source IP address field in the received uplink packet matches the source IP address in the acquired identification information, then the received uplink packet is determined to be an applicable UL packet to be forwarded to first device 110.

[0165] In some example embodiments, alternatively or additionally, third device 130 may determine an applicable UL packet to forward to first device 110 based on whether an IP address included in a destination IP address field in a received uplink packet matches the destination IP address in the obtained identification information.

[0166] In some example embodiments, alternatively or additionally, third device 130 may determine an applicable UL packet to forward to first device 110 based on whether a routing identifier included in the received uplink packet matches a UL routing identifier in the acquired identification information.

[0167] In some example embodiments, third device 130 may alternatively or additionally determine an applicable UL packet to forward to first device 110 based on whether a BAP address included in a received uplink packet matches a BAP address in the acquired identification information.

[0168] In some example embodiments, third device 130 may alternatively or additionally determine an applicable UL packet to forward to first device 110 based on whether a flow label in an IP header of a received uplink packet matches a flow label in the obtained identification information.

[0169] In some example embodiments, third device 130 may alternatively or additionally determine the applicable UL packet to forward to first device 110 based on whether a differentiated services code point value in an IP header of the received uplink packet matches the differentiated services code point in the obtained identification information.

[0170] The above-described methods 600, 700, and 800 can avoid uplink packet loss, for example, during inter-donor-DU migration. Furthermore, method 800 can avoid violating security policies in the transport network and the IAB-donor-DU. In other words, source filtering can be applied normally to rerouted packets in the transport network and the IAB-donor-DU.

[0171] In some embodiments, the first device may be a source donor-DU of an IAB node, the second device may be a donor-CU, the third device may be a target donor-DU of an IAB node, and the fourth device may be an IAB node.

[0172] In some example embodiments, a first apparatus (e.g., first device 110) capable of performing any of method 600 may include a component for performing the corresponding operation of method 600. The component may be implemented in any suitable form. For example, the component may be implemented in a circuit or a software module. The first apparatus may be implemented as or included in first device 110. In some example embodiments, the component may include a processor and a memory.

[0173] In some example embodiments, the first device includes components for: receiving, at the first device, from a second device in communication with the first device, a request to establish at least one tunnel between the first device and a third device; sending, to the second device, tunnel information about the at least one tunnel to be established between the first device and the third device; and receiving, from a fourth device via the third device and the at least one tunnel, at least one uplink packet destined for the first device.

[0174] In some example embodiments, the at least one tunnel includes a first tunnel, and the tunnel information includes at least one of the following for the first tunnel: an Internet Protocol address of the first device, an identification of a tunnel endpoint associated with the first tunnel, or a format of at least one uplink packet.

[0175] In some example embodiments, at least one uplink packet destined for the first device includes at least one of the following identifiers associated with the first apparatus 110: a source IP address, a destination IP address, a BAP address, a BAP routing identifier, a flow label, or a differentiated services code point.

[0176] In some example embodiments, the request indicates at least one of: a format of at least one uplink packet, a number of at least one tunnel to establish.

[0177] In some example embodiments, the first device further includes components for: determining whether at least one uplink packet includes at least one Backhaul Adaptation Protocol (BAP) header; and if it is determined that the at least one uplink packet includes the at least one BAP header, determining whether the at least one uplink packet is targeted for the first device based on the at least one BAP header, and if it is determined that the at least one uplink packet is targeted for the first device 110, removing the at least one BAP header from the at least one uplink packet, and forwarding the at least one uplink packet without the at least one BAP header to the second device or the security gateway; and if it is determined that the at least one uplink packet does not include the BAP header, forwarding the at least one uplink packet to the second device or the security gateway.

[0178] In some example embodiments, a second device (e.g., second device 120) capable of performing any of method 700 may include a component for performing the corresponding operation of method 700. The component may be implemented in any suitable form. For example, the component may be implemented in a circuit or a software module. The second device may be implemented as second device 120 or included in second device 120. In some example embodiments, the device may include a processor and a memory.

[0179] In some example embodiments, the second device includes a device for: sending, from the second device to a first device communicating with the second device, a request to establish at least one tunnel between the first device and a third device for forwarding, from the third device to the first device, at least one uplink packet from a fourth device destined for the first device; receiving tunnel information about the at least one tunnel from the first device; providing the tunnel information to the third device for establishing the at least one tunnel; and providing, to the third device, identification information about at least one uplink packet to be forwarded from the third device to the first device via the at least one tunnel.

[0180] In some embodiments, the various examples of at least one tunnel, request, tunnel information, and identification information described above with reference to methods 600 - 800 and the first device also apply here.

[0181] In some example embodiments, a third apparatus (e.g., third device 130) capable of performing any of method 800 may include a component for performing the corresponding operation of method 800. The component may be implemented in any suitable form. For example, the component may be implemented in a circuit or a software module. The third apparatus may be implemented as or included in third device 130. In some example embodiments, the component may include a processor and a memory.

[0182] In some example embodiments, the third device includes components for: obtaining, at the third device, tunnel information from the second device about at least one tunnel to be established between the third device and the first device; obtaining, from the second device, identification information about at least one uplink packet, the at least one uplink packet coming from the fourth device and destined for the first device and to be forwarded to the first device and the third device via the at least one tunnel; and forwarding the received uplink packet to the first device via one of the at least one tunnel if it is determined that the uplink packet received from the fourth device includes the obtained identification information.

[0183] In some embodiments, the various examples of at least one tunnel, tunnel information, and identification information described above with reference to methods 600-800, the first device, and the second device also apply here.

[0184] In some example embodiments, the above determination is based on at least one of the following: the IP address included in the source IP address field of the received uplink packet matches the source IP address in the obtained identification information; the IP address included in the destination IP address field of the received uplink packet matches the destination IP address in the obtained identification information; the routing identifier included in the received uplink packet matches the BAP routing identifier in the obtained identification information; the BAP address included in the received uplink packet matches the BAP address in the obtained identification information; the flow label in the IP header of the received uplink packet matches the flow label in the obtained identification information; or the differentiated services code point value in the IP header of the received uplink packet matches the differentiated services code point in the obtained identification information.

[0185] Figure 9 is a simplified block diagram of a device 900 suitable for implementing an example embodiment of the present disclosure. The device 900 may be provided to implement a communication device, such as Figure 1 The first device 110, the second device 120 or the third device 130 is shown. As shown, the device 900 includes one or more processors 910, one or more memories 920 coupled to the processor 910, and one or more communication modules 940 coupled to the processor 910.

[0186] The communication module 940 is configured for bidirectional communication. The communication module 940 includes one or more communication interfaces to facilitate communication with one or more other modules or devices. A communication interface may represent any interface required for communication with other network elements. In some exemplary embodiments, the communication module 940 may include at least one antenna.

[0187] Processor 910 may be of any type suitable for the local technology network and may include one or more of the following: as non-limiting examples, 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 900 may have multiple processors, such as application specific integrated circuit chips, that are time-slave to a clock that synchronizes a master processor.

[0188] The memory 920 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) 924, electrically programmable read-only memory (EPROM), flash memory, hard disks, compact disks (CDs), digital video disks (DVDs), optical disks, laser disks, and other magnetic and / or optical storage devices. Examples of volatile memories include, but are not limited to, random access memory (RAM) 922 and other volatile memories that do not persist across a power outage.

[0189] Computer program 930 includes computer-executable instructions that are executable by the associated processor 910. Program 930 may be stored in a memory such as ROM 924. Processor 910 may perform any suitable actions and processes by loading program 930 into RAM 922.

[0190] The exemplary embodiments of the present disclosure may be implemented with the aid of a program 930, so that the device 900 may execute the procedures described in the reference Figures 2 to 8 Any process of the present disclosure discussed. The example embodiments of the present disclosure may also be implemented by hardware or a combination of software and hardware.

[0191] In some example embodiments, the program 930 may be tangibly embodied in a computer-readable medium that may be included in the device 900 (e.g., in the memory 920) or in another storage device accessible by the device 900. The device 900 may load the program 930 from the computer-readable medium to the RAM 922 for execution. The computer-readable medium may include any type of tangible, non-volatile memory, such as ROM, EPROM, flash memory, hard disk, CD, DVD, etc. Figure 10 An example of a computer readable medium 1000 is shown which may be in the form of a CD, DVD or other optical storage disc. The computer readable medium has a program 930 stored thereon.

[0192] In general, various 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, which may be executed by a controller, microprocessor, or other computing device. Although various aspects of the embodiments of the present disclosure are shown and described as block diagrams, flow charts, or using some other pictorial representations, it should be understood that the blocks, devices, systems, techniques, or methods described herein may be implemented, as non-limiting examples, in hardware, software, firmware, dedicated circuits or logic, general-purpose hardware or a controller or other computing device, or some combination thereof.

[0193] The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer readable storage medium. The computer program product includes computer executable instructions, such as instructions included in a program module executed in a device on a target physical or virtual processor to perform the above-referenced Figures 2 to 8 Any method described herein. Generally speaking, program modules include routines, programs, libraries, objects, classes, components, data structures, etc. that perform specific tasks or implement specific abstract data types. The functionality of program modules can be combined or separated between program modules as needed in various embodiments. The machine-executable instructions of program modules can be executed on local or distributed devices. In distributed devices, program modules can be located in local and remote storage media.

[0194] The program code for executing the method of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general-purpose computer, a special-purpose computer, or other programmable data processing device so that when the program code is executed by the processor or controller, the functions / operations specified in the flow chart and / or block diagram are implemented. The program code may be executed entirely on the machine, partially on the machine, as a stand-alone software package, partially on the machine, partially on a remote machine, or entirely on a remote machine or server.

[0195] 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.

[0196] 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, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of computer-readable storage media would include an electrical connection having one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0197] It should be understood that although some embodiments can be implemented by / at an IAB node, the solutions including the methods and devices proposed in the present disclosure can also be applied to other communication systems with similar technical problems. In addition, although the operations are described in a specific order, this should not be understood as requiring that these operations be performed in the specific order shown or in sequence, or that all the operations shown be performed to achieve 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 details should not be interpreted as limiting the scope of the present disclosure, but should be interpreted as descriptions of features unique to specific embodiments. Certain features described in the context of a separate embodiment 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 in multiple embodiments individually or in any suitable sub-combination.

[0198] Although the present disclosure has been described in language specific to structural features and / or methodological acts, it should be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Instead, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

1. A first apparatus for communication, 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, with the at least one processor, cause the first apparatus to: receiving, from a second device, a request to establish at least one tunnel between the first device and a third device; sending, to the second device, tunnel information about the at least one tunnel to be established between the first device and the third device; receiving, from a fourth device via the third device and the at least one tunnel, at least one uplink packet destined for the first device; as well as If it is determined based on at least one Backhaul Adaptation Protocol (BAP) header included in the at least one received uplink packet that the at least one uplink packet is destined for the first apparatus, then: removing the at least one BAP header from the at least one uplink packet, and The at least one uplink packet without the at least one BAP header is forwarded to the second device or a security gateway.

2. The first apparatus according to claim 1, wherein the at least one tunnel comprises a first tunnel, and the tunnel information comprises at least one of the following for the first tunnel: the Internet Protocol address of the first device, an identification of a tunnel endpoint associated with the first tunnel, or The format of the at least one uplink packet.

3. The first apparatus of claim 1 , wherein the at least one uplink packet targeted to the first apparatus comprises at least one of the following associated with the first apparatus: Source Internet Protocol (IP) address, Destination IP address, Backhaul Adaptation Protocol BAP address, BAP routing identifier, flow label, or Differentiated Services Code Point.

4. The first apparatus according to any one of claims 1 to 3, wherein the request indicates at least one of the following: the format of the at least one uplink packet, or The number of the at least one tunnel to be established.

5. A second device for communication, 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, with the at least one processor, cause the second apparatus to: sending a request to a first device to establish at least one tunnel between the first device and a third device for forwarding at least one uplink packet from a fourth device destined for the first device from the third device to the first device; receiving tunnel information about the at least one tunnel from the first device; providing the tunnel information to the third device for establishing the at least one tunnel; providing, to the third device, identification information regarding at least one uplink packet to be forwarded from the third device to the first device through the at least one tunnel; as well as The at least one uplink packet is received from the first device without at least one Backhaul Adaptation Protocol (BAP) header.

6. The second device according to claim 5, wherein the at least one tunnel comprises a first tunnel, and the tunnel information comprises at least one of the following for the first tunnel: the Internet Protocol address of the first device, an identification of a tunnel endpoint associated with the first tunnel, or The format of the at least one uplink packet.

7. The second device according to claim 5, wherein the identification information comprises at least one of the following identifications associated with the first device: Source Internet Protocol (IP) address, Destination IP address, Backhaul Adaptation Protocol BAP address, BAP routing identifier, flow label, or Differentiated Services Code Point.

8. The second apparatus according to any one of claims 5 to 7, wherein the request indicates at least one of the following: the format of the at least one uplink packet, or The number of the at least one tunnel.

9. A third apparatus for communication, 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, with the at least one processor, cause the third apparatus to: acquiring, from the second device, tunnel information about at least one tunnel to be established between the third device and the first device; acquiring, from the second device, identification information about at least one uplink packet, the at least one uplink packet originating from a fourth device and destined for the first device, and the at least one uplink packet to be forwarded to the first device via the at least one tunnel and the third device; as well as If it is determined that the uplink packet received from the fourth device includes the acquired identification information, the received uplink packet is forwarded to the first device via one of the at least one tunnel.

10. The third apparatus according to claim 9, wherein the at least one tunnel comprises a first tunnel, and the tunnel information comprises at least one of the following for the first tunnel: the Internet Protocol address of the first device, an identification of a tunnel endpoint associated with the first tunnel, or The format of the at least one uplink packet.

11. The third apparatus according to claim 9 or 10, wherein the determination is based on at least one of the following: The Internet Protocol IP address included in the source IP address field of the received uplink packet matches the source IP address in the obtained identification information; The IP address included in the destination IP address field of the received uplink packet matches the destination IP address in the acquired identification information; The routing identifier included in the received uplink packet matches the Backhaul Adaptation Protocol (BAP) routing identifier in the acquired identification information; The BAP address included in the received uplink packet matches the BAP address in the acquired identification information; The flow label in the IP header of the received uplink packet matches the flow label in the obtained identification information; or A Differentiated Services Code Point value in the IP header of the received uplink packet matches a Differentiated Services Code Point in the acquired identification information.

12. A method for communication, comprising: receiving, at a first device, from a second device, a request to establish at least one tunnel between the first device and a third device; sending, to the second device, tunnel information about the at least one tunnel to be established between the first device and the third device; as well as receiving, from a fourth device via the third device and the at least one tunnel, at least one uplink packet destined for the first device; as well as If it is determined based on at least one Backhaul Adaptation Protocol (BAP) header included in the at least one received uplink packet that the at least one uplink packet is targeted for the first device, then: removing the at least one BAP header from the at least one uplink packet, and The at least one uplink packet without the at least one BAP header is forwarded to the second device or a security gateway.

13. A method for communication, comprising: sending, from a second device to a first device, a request to establish at least one tunnel between the first device and a third device for forwarding, from the third device to the first device, at least one uplink packet from a fourth device destined for the first device; receiving tunnel information about the at least one tunnel from the first device; Providing the tunnel information to the third device for establishing the at least one tunnel; as well as providing, to the third device, identification information regarding at least one uplink packet to be forwarded from the third device to the first device through the at least one tunnel; as well as The at least one uplink packet is received from the first device without at least one Backhaul Adaptation Protocol (BAP) header.

14. A method for communication, comprising: acquiring, at a third device, from a second device, tunnel information about at least one tunnel to be established between the third device and the first device; acquiring, from the second device, identification information about at least one uplink packet, the at least one uplink packet originating from a fourth device and destined for the first device, and the at least one uplink packet to be forwarded to the first device via the at least one tunnel and the third device; as well as If it is determined that the uplink packet received from the fourth device includes the acquired identification information, the received uplink packet is forwarded to the first device via one of the at least one tunnel.

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