Procedure for transmission-reception point change in relay operation

Abstract

Embodiments of the present disclosure relate to methods, devices, apparatuses and computer readable storage medium for a procedure for a transmission-reception point (TRP) change in a relay operation. The method includes: determining, at a centralized network node, that a TRP change for the backhaul link of a relay device is to be initiated; and based on the determination, transmitting, at the centralized network node, to a distributed network node controlled by the centralized network node, a configuration of a preparation of a relay operation associated with the relay device for the distributed network node, wherein a forward link associated with the relay operation is to be established between a user device and a TRP associated with the distributed network node for the TRP change.

Description

PROCEDURE FOR TRANSMISSION-RECEPTION POINT CHANGE IN RELAY OPERATIONFIELDS

[0001] Various example embodiments of the present disclosure generally relate to the field of telecommunication and in particular, to methods, devices, apparatuses and computer readable storage medium for a procedure for a transmission-reception point (TRP) change in a relay operation.BACKGROUND

[0002] Improving coverage is critical as it directly impacts performance and user experience. Network coverage can be expanded and enhanced by deploying additional cells (individual base stations or access points). In some scenarios, repeaters are also required to provide a more cost-effective solution.SUMMARY

[0003] In a first aspect of the present disclosure, there is provided an apparatus. The apparatus comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to: determine that a TRP change for a backhaul link of the relay device is to be initiated; and based on the determination, transmit, to a distributed network node controlled by the apparatus, a configuration of a preparation of a relay operation associated with the relay device for the distributed network node, wherein a forward link associated with the relay operation is to be established between a user device and a TRP associated with the distributed network node for the TRP change.

[0004] In a second aspect of the present disclosure, there is provided an apparatus. The apparatus comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to: during a TRP change for a backhaul link of the relay device, transmit, to the relay device, an indication that a relay operation associated with the relay device is to be changed to a TRP associated with a distributed network node for the TRP change, wherein a forward link associated with the relay operation is to be established between the user device and theTRP during the TRP change, and wherein the distributed network node is controlled by a further centralized network node other than the apparatus.

[0005] In a third aspect of the present disclosure, there is provided an apparatus. The apparatus comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to: receive, from a centralized network node, a configuration of a preparation of a relay operation associated with a relay device for the apparatus, wherein a forward link associated with the relay operation is to be established between a user device and a TRP associated with the apparatus for the TRP change for a backhaul link of the relay device ; and cause, based on the configuration, the forward link associated with the relay operation to be established between the user device and the TRP associated with the apparatus during the TRP change.

[0006] In a fourth aspect of the present disclosure, there is provided an apparatus. The apparatus comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to: receive, from a centralized network node, an indication that a relay operation associated with the apparatus is to be changed from a TRP to associated with a distributed network node to a further TRP associated with a distributed network node or a further distributed network node for the TRP change for a backhaul link of the relay device, wherein a forward link associated with the relay operation is to be established between the user device and the further TRP during the TRP change; and establish, based on the indication, the forward link between the user device and the further TRP during the TRP change.

[0007] In a fifth aspect of the present disclosure, there is provided a method. The method comprises: determining, at a centralized network node, that a TRP change for a backhaul link of the relay device is to be initiated; and based on the determination, transmitting, at the centralized network node, to a distributed network node controlled by the centralized network node, a configuration of a preparation of a relay operation associated with the relay device for the distributed network node, wherein a forward link associated with the relay operation is to be established between a user device and a TRP associated with the distributed network node for the TRP change.

[0008] In a sixth aspect of the present disclosure, there is provided a method. The method comprises: during a TRP change for a backhaul link of the relay device, transmitting, at a centralized network node, to the relay device, an indication that a relayoperation associated with the relay device is to be changed to a TRP associated with a distributed network node for the TRP change, wherein a forward link associated with the relay operation is to be established between the user device and the TRP during the TRP change, and wherein the distributed network node is controlled by a further centralized network node other than the centralized network node.

[0009] In a seventh aspect of the present disclosure, there is provided a method. The method comprises: receiving, at a distributed network node, from a centralized network node, a configuration of a preparation of a relay operation associated with a relay device for the distributed network node, wherein a forward link associated with the relay operation is to be established between a user device and a TRP associated with the distributed network node for a TRP change for a backhaul link of the relay device; and causing, at the distributed network node, based on the configuration, the forward link associated with the relay operation to be established between the user device and the TRP associated with the distributed network node during the TRP change.

[0010] In an eighth aspect of the present disclosure, there is provided a method. The method comprises: receiving, at a relay node, from a centralized network node, an indication that a relay operation associated with the relay node is to be changed from a TRP to associated with a distributed network node to a further TRP associated with a distributed network node or a further distributed network node for a TRP change for a backhaul link of the relay device, wherein a forward link associated with the relay operation is to be established between the user device and the further TRP during the TRP change; and establishing, at the relay node, based on the indication, the forward link between the user device and the further TRP during the TRP change.

[0011] In a ninth aspect of the present disclosure, there is provided a first apparatus. The first apparatus comprises means for determining that a TRP change for a backhaul link of the relay device is to be initiated; and means for based on the determination, transmitting, to a distributed network node controlled by the apparatus, a configuration of a preparation of a relay operation associated with the relay device for the distributed network node, wherein a forward link associated with the relay operation is to be established between a user device and a TRP associated with the distributed network node for the TRP change.

[0012] In a tenth aspect of the present disclosure, there is provided a second apparatus.The second apparatus comprises means for during a TRP change for a backhaul link of the relay device, transmitting, to the relay device, an indication that a relay operation associated with the relay device is to be changed to a TRP associated with a distributed network node for the TRP change, wherein a forward link associated with the relay operation is to be established between the user device and the TRP during the TRP change, and wherein the distributed network node is controlled by a further centralized network node other than the apparatus.

[0013] In an eleventh aspect of the present disclosure, there is provided a third apparatus. The third apparatus comprises means for receiving, from a centralized network node, a configuration of a preparation of a relay operation associated with a relay device for the apparatus, wherein a forward link associated with the relay operation is to be established between a user device and a TRP associated with the apparatus for a TRP change for a backhaul link of the relay device; and means for causing, based on the configuration, the forward link associated with the relay operation to be established between the user device and the TRP associated with the apparatus during the TRP change.

[0014] In a twelfth aspect of the present disclosure, there is provided a fourth apparatus. The fourth apparatus comprises means for receiving, from a centralized network node, an indication that a relay operation associated with the apparatus is to be changed from a TRP to associated with a distributed network node to a further TRP associated with a distributed network node or a further distributed network node for a TRP change for a backhaul link of the relay device, wherein a forward link associated with the relay operation is to be established between the user device and the further TRP during the TRP change; and means for establishing, based on the indication, the forward link between the user device and the further TRP during the TRP change.

[0015] In a thirteenth aspect of the present disclosure, there is provided a computer readable medium. The computer readable medium comprises instructions stored thereon for causing an apparatus to perform at least the method according to the fifth aspect.

[0016] In a fourteenth aspect of the present disclosure, there is provided a computer readable medium. The computer readable medium comprises instructions stored thereon for causing an apparatus to perform at least the method according to the sixth aspect.

[0017] In a fifteenth aspect of the present disclosure, there is provided a computer readable medium. The computer readable medium comprises instructions stored thereonfor causing an apparatus to perform at least the method according to the seventh aspect.

[0018] In a sixteenth aspect of the present disclosure, there is provided a computer readable medium. The computer readable medium comprises instructions stored thereon for causing an apparatus to perform at least the method according to the eighth aspect.

[0019] It is to be understood that the Summary section is not intended to identify key or essential features of 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 easily comprehensible through the following description.BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Some example embodiments will now be described with reference to the accompanying drawings, where:

[0021] FIG. 1 illustrates an example communication environment in which example embodiments of the present disclosure can be implemented;

[0022] FIG. 2A illustrates an example scenario of TRPs served by the same CU and different DUs;

[0023] FIG. 2B illustrates an example scenario of TRPs served by different CUs and DUs;

[0024] FIG. 2C illustrates an example scenario of TRPs served by the same CU and same DU;

[0025] FIG. 3 illustrates a signaling chart of an example process for a TRP change in a relay operation according to some example embodiments of the present disclosure;

[0026] FIG. 4 illustrates a signaling chart of another example process for a TRP change in a relay operation according to some example embodiments of the present disclosure;

[0027] FIG. 5 illustrates a flowchart of a method implemented at a centralized network node according to some example embodiments of the present disclosure;

[0028] FIG. 6 illustrates a flowchart of a method implemented at a centralized network node according to some example embodiments of the present disclosure;

[0029] FIG. 7 illustrates a flowchart of a method implemented at a distributed network node according to some example embodiments of the present disclosure;

[0030] FIG. 8 illustrates a flowchart of a method implemented at a relay node according to some example embodiments of the present disclosure;

[0031] FIG. 9 illustrates a simplified block diagram of a device that is suitable for implementing example embodiments of the present disclosure; and

[0032] FIG. 10 illustrates a block diagram of an example computer readable medium in accordance with some example embodiments of the present disclosure.

[0033] Throughout the drawings, the same or similar reference numerals represent the same or similar element.DETAILED DESCRIPTION

[0034] Principle of the present disclosure will now be described with reference to some example embodiments. It is to be understood that these embodiments are described only for the purpose of illustration and help those skilled in the art to understand and implement the present disclosure, without suggesting any limitation as to the scope of the disclosure. Embodiments described herein can be implemented in various manners other than the ones described below.

[0035] 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 skills in the art to which this disclosure belongs.

[0036] References in the present disclosure to “one embodiment,” “an embodiment,” “an example embodiment,” and the like indicate that the embodiment described may include a particular feature, structure, or characteristic, but it is not necessary that every embodiment includes the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

[0037] It shall be understood that although the terms “first,” “second,”..., etc. in front of noun(s) 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 and they do not limit the order of the noun(s). For example, a first elementcould be termed a second element, and similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term “and / or” includes any and all combinations of one or more of the listed terms.

[0038] As used herein, “at least one of the following: ” and “at least one of ” and similar wording, where the list of two or more elements are joined by “and” or “or”, mean at least any one of the elements, or at least any two or more of the elements, or at least all the elements.

[0039] As used herein, unless stated explicitly, performing a step “in response to A” does not indicate that the step is performed immediately after “A” occurs and one or more intervening steps may be included.

[0040] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises”, “comprising”, “has”, “having”, “includes” and / or “including”, when used herein, specify the presence of stated features, elements, and / or components etc., but do not preclude the presence or addition of one or more other features, elements, components and / or combinations thereof.

[0041] As used in this application, the term “circuitry” may refer to one or more or all of the following:(a) hardware-only circuit implementations (such as implementations in only analog and / or digital circuitry) and(b) combinations of hardware circuits and software, such as (as applicable):(i) a combination of analog and / or digital hardware circuit(s) with software / firmware and(ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and(c) hardware circuit(s) and or processor(s), such as a microprocessor(s) or aportion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.

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

[0043] As used herein, the term “communication network” refers to a network following any suitable communication standards, such as New Radio (NR), Long Term Evolution (LTE), LTE-Advanced (LTE-A), Wideband Code Division Multiple Access (WCDMA), High-Speed Packet Access (HSPA), Narrow Band Internet of Things (NB-IoT) and so on. Furthermore, the communications between a terminal device and a network device in the communication network may be performed according to any suitable generation communication protocols, including, but not limited to, the first generation (1G), the second generation (2G), 2.5G, 2.75G, the third generation (3G), the fourth generation (4G), 4.5G, the fifth generation (5G), the sixth generation (6G) communication protocols, and / or any other protocols either currently known or to be developed in the future. Embodiments of the present disclosure may be applied in various communication systems. Given the rapid development in communications, there will of course also be future type communication technologies and systems with which the present disclosure may be embodied. It should not be seen as limiting the scope of the present disclosure to only the aforementioned system.

[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 therefrom. The network device may refer to a base station (BS) or an access point (AP), for example, a node B (NodeB or NB), an evolved NodeB (eNodeB or eNB), an NR NB (also referred to as a gNB), a Remote Radio Unit (RRU), a radio header (RH), a remote radio head (RRH), a relay, an Integrated Access and Backhaul (IAB) node, a low power node such as a femto, a pico, a non-terrestrial network (NTN) or non-ground network device such asa satellite network device, a low earth orbit (LEO) satellite and a geosynchronous earth orbit (GEO) satellite, an aircraft network device, and so forth, depending on the applied terminology and technology. In some example embodiments, radio access network (RAN) split architecture comprises a Centralized Unit (CU) and a Distributed Unit (DU) at an IAB donor node. An IAB node comprises a Mobile Terminal (IAB-MT) part that behaves like a UE toward the parent node, and a DU part of an IAB node behaves like a base station toward the next-hop IAB node.

[0045] The term “terminal device” refers to any end device that may be capable of wireless communication. By way of example rather than limitation, a terminal device may also be referred to as a communication device, user equipment (UE), a Subscriber Station (SS), a Portable Subscriber Station, a Mobile Station (MS), or an Access Terminal (AT). The terminal device may include, but not limited to, a mobile phone, a cellular phone, a smart phone, voice over IP (VoIP) phones, wireless local loop phones, a tablet, a wearable terminal device, a personal digital assistant (PDA), portable computers, desktop computer, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, vehicle-mounted wireless terminal devices, wireless endpoints, mobile stations, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), USB dongles, smart devices, wireless customer-premises equipment (CPE), an Internet of Things (loT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and applications (e.g., remote surgery), an industrial device and applications (e.g., a robot and / or other wireless devices operating in an industrial and / or an automated processing chain contexts), a consumer electronics device, a device operating on commercial and / or industrial wireless networks, and the like. The terminal device may also correspond to a Mobile Termination (MT) part of an IAB node (e.g., a relay node). In the following description, the terms “terminal device”, “communication device”, “terminal”, “user equipment” and “UE” may be used interchangeably.

[0046] As used herein, the term “resource,” “transmission resource,” “resource block,” “physical resource block” (PRB), “uplink resource,” or “downlink resource” may refer to any resource for performing a communication, for example, a communication between a terminal device and a network device, such as a resource in time domain, a resource in frequency domain, a resource in space domain, a resource in code domain, or any other combination of the time, frequency, space and / or code domain resource enabling acommunication, and the like. In the following, unless explicitly stated, a resource in both frequency domain and time domain will be used as an example of a transmission resource for describing some example embodiments of the present disclosure. It is noted that example embodiments of the present disclosure are equally applicable to other resources in other domains.

[0047] As mentioned above, providing a better coverage is essential to enhance and guarantee the performance of UE. Deploying additional cells can improve the coverage as well as the capacity in a specific area, but such solution is not preferred by operators due to high costs and limited backhaul options. The introduction of Integrated Access and Backhaul (IAB) has provided a solution for coverage extension and capacity improvement, but it comes with high costs. Alternatively, radio frequency (RF) repeaters have been a legacy solution for coverage extension and are preferred by the operators specifically due to the low cost.

[0048] However, in certain deployment scenarios, providing the coverage in Frequency Range 2 (FR2) can be challenging due to degraded propagation characteristics. For example, serving users around the corner of a building or providing indoor coverage using FR2 band may not be possible. In such cases, NR repeaters can be useful as they offer a cost-efficient solution for the operators compared to deploying Base Stations (BSs) or lABs.

[0049] The requirements for basic repeaters (i.e., RF) is specified as operating in a “dumb” manner. However, there are plans to continue specifying control functionalities to enable smart features for repeater operation. These smart features would support New Radio (NR) capabilities such as dynamic Time Division Duplex (TDD) and UE-specific beam management.

[0050] The control of smart repeater functions may be provided either over the NR connection or via a dedicated wireless connection between the serving gNB and the repeater. The repeater type is expected to be an amplification-and-forward (A / F) type, where the UE and DE signals pass through the repeater in the analog domain.

[0051] In some proposals, the synchronization of DE signals and TDD patterns is assumed to be obtained through the mobile termination (MT) / UE function hosted by the repeater.

[0052] Unlike dumb repeaters, smart repeaters could use side control information to enable intelligent amplify-and-forward processes. This side information may include TDD-related details such as UL / DL slot and symbol configuration or slot format indication, as well as spatial information for multi-beam operations (transmitter and receiver beam information). The dumb repeaters lack the necessary control information for adaptive beamforming, making it impossible. However, smart repeaters can employ adaptive beamforming towards individual users, which enhances coverage, particularly in FR2 (higher frequency bands).

[0053] Initially, a certain number of beams are allocated by the gNB for the backhaul link. These beams are then directly associated with the beams of the smart repeater to facilitate access link communication between the smart repeater and the UE. Each beam pair is responsible for transmitting the data and control information to the UEs within the repeater’s coverage. To configure the beam pair links, the necessary information must be sent to the smart repeater. The mapping and distribution of backhaul beams can either be pre-configured or dynamically adjusted by sending control information to the repeater in real-time (which is a smart feature). UEs within the repeater’s coverage may report the beam-per-link related measurements to the gNB, and the procedures for such reporting are assumed to be the same as existing methods.

[0054] The actual repetition of signals in the repeater is amplify-and-forward (A / F) type, where the received signal is amplified in the transmitter power amplifier (PA) and then transmitted without decoding. This process occurs in both the UL and DL directions.

[0055] The main issue of an A / F repeater is that it is amplifies everything it receives on the forward path, including noise and interference. As a result, a repeater is considered a sub-optimal network node and can be utilized for coverage extension in limited radio network scenarios.

[0056] The repeater may have UE (or MT) functionality, allowing it to establish a connection to the serving node (gNB) and receive control information from it. The network-controlled repeater (NCR) MT can synchronize with the DL SSB, decode system information for cell configurations, receive physical downlink control channel (PDCCH) channel for radio resource control, etc. The control link may be either one-directional (DL only) or bi-directional connection, and control signaling can occur at the radio resource control (RRC) (static / semi- static configurations), medium access control (MAC) (semi-static control) or physical (PHY) (PDCCH, dynamic control) layers.

[0057] The backhaul (BH) connection of the NCR may sometimes fail, or the quality may become worse than acceptable for signal forwarding. For that, it would be good to have another cell or beam available via another TRP providing a redundant connection or a fallback link in case of link failure to the serving node. Preferably the redundant connection should be taken into use quickly when experiencing issues on the current connection. Furthermore, when changing the TRP, i.e., the beam or cell that is repeated to the UEs on the NCR access link, the UEs will experience a cell or beam change so that they should initiate either re-establishment procedure or beam failure recovery.

[0058] The NCR antenna configuration on the BH connection can be with one antenna panel, or there can be separate panels for the two connections to TRP1 and TRP2. This is an implementation option and dependent on the physical deployment of the TRPs: e.g., there may not be good enough connection to both TRPs with a single panel requiring two separate panels pointing to different directions.

[0059] As described above, there are several issues that need to be addressed and resolved, for example, how to prepare the TRPs and NCR to enable fastest possible change of the BH connection between two serving TRPs and how to configure UEs to be able to either re-establish or to be handed over to the new cell or beam when the forwarding link is changed from TRP to another.

[0060] Furthermore, it is unclear what shall be the signaling procedure for the preparation, how to define the solution to be applicable for UEs without any knowledge about the NCR deployment, and what should be the extensions to the signaling over the network interfaces to support the NCR solution.

[0061] According to some example embodiments of the present disclosure, there is provided a solution for a procedure for a TRP change in a relay operation. In the solution, a CU determines that a TRP change for the NCR backhaul link is to be initiated. Based on the determination, the CU transmits, to a DU controlled by the CU, a configuration of a preparation of a relay operation associated with a relay device for the DU. A forward link associated with the relay operation is to be established between a UE and a TRP associated with the DU for the TRP change.

[0062] In this way, the procedure enables UEs to maintain their connection despitesudden changes in the served cell / beam(s) on the NCR access link. This ensures uninterrupted connectivity for UEs, even when encountering such changes. The network control is maintained throughout the procedure, allowing for effective management of UE behavior in these scenarios. This is achieved even when UEs have no knowledge of the NCR deployment and only support legacy features, ensuring compatibility and seamless operation. The procedure aims to minimize the impact on UEs, ensuring the best possible user experience. This includes avoiding long interruptions caused by lost connections or the need to establish new connections. By implementing this procedure, the goal is to provide seamless connectivity, maintain network control, and minimize disruptions, ultimately enhancing the overall user experience.

[0063] Example embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.

[0064] FIG. 1 illustrates an example communication environment 100 in which example embodiments of the present disclosure can be implemented. The communication environment 100 may comprise a first CU 110 (hereinafter may also be referred to as a centralized network node) and a first DU 130 and a second DU 140 (hereinafter each may also be referred to as a distributed network node). The first CU 110 may manage / control both the first DU 130 and the second DU 140. The CU 110 may communicate with the first DU 130 and the second DU 140. A CU and a DU communicating with the CU can co-locate in the same physical network node, or they can locate in separate physical network entities.

[0065] For example, the first CU 110 may communicate with the first DU 130 via an Fl connection and communicate with the second DU 140 via another Fl connection. The communication environment further involves one or more UEs 160 (hereinafter may also be referred to as user device collectively). The one or more UEs 160 may communicate with the first DU 130 or the second DU 140 via a network-controlled repeater (NCR) 150 (hereinafter may also referred to as a relay device or a smart repeater). The NCR may be used for transferring signals between DUs and UEs in UL and DL, which will be described in detail with reference to FIGS. 2A and 2B.

[0066] In some example embodiments, the communication environment may further involve a second CU 120 (hereinafter may also be referred to as a centralized network node). In some scenarios, the first CU 110 may control the first DU 130 and the secondCU 130 may control the second DU 140. The first CU 110 may communicate with the second CU 120, for example, via an Xn connection.

[0067] It is to be understood that the number of user devices and network devices shown in FIG. 1 is given for the purpose of illustration without suggesting any limitations. The communication environment 100 may include any suitable number of units or devices mentioned above.

[0068] Communications in the communication environment 100 may be implemented according to any proper communication protocol(s), comprising, but not limited to, cellular communication protocols of the first generation (1G), the second generation (2G), the third generation (3G), the fourth generation (4G), the fifth generation (5G), the sixth generation (6G), and the like, wireless local network communication protocols such as Institute for Electrical and Electronics Engineers (IEEE) 802.11 and the like, and / or any other protocols currently known or to be developed in the future. Moreover, the communication may utilize any proper wireless communication technology, comprising 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 Multiple (OFDM), Discrete Fourier Transform spread OFDM (DFT-s-OFDM) and / or any other technologies currently known or to be developed in the future.

[0069] For the TRP change, there may be multiple network scenarios, which will be described in detail with reference to FIGS. 2A and 2B.

[0070] FIG. 2A illustrates an example scenario 200A of TRPs served by the same CU and different DUs. The example scenario 200 A involves a CU 210 (may refer to the first CU 110 in FIG. 1), a DU 230 (may refer to the first DU 130 in FIG. 1), a DU 240 (may refer to the second DU 140 in FIG. 1), a TRP 270, a TRP 280, an NCR 290 (may refer to the NCR 150 in FIG. 1) and one or more UEs 260 (may refer to the one or more UEs 160 in FIG. 1).

[0071] In the scenario of FIG. 2A, the CU 210 may control both DU 230 and DU 240. The TRP 270 may be associated with the DU 230 or managed by the DU 230. The TRP 280 may be associated with the DU 240 or managed by the DU 240. The UE 260 may access TRP 270 via the NCR 290 or access the TRP 280 via NCR 290. A beam associatedwith the TRP 270 may refer to a SSB beam, e.g., a SSBX and a beam associated with the TRP 280 may refer to a further SSB beam, e.g., SSBY.

[0072] FIG. 2B illustrates an example scenario 200B of TRPs served by different CUs and DUs. The example scenario 200B involves a CU 210 (may refer to the first CU 110 in FIG. 1), a CU 220 (may refer to the second CU 120 in FIG. 1), a DU 230 (may refer to the first DU 130 in FIG. 1), a DU 240 (may refer to the second DU 140 in FIG. 1), a TRP 270, a TRP 280, an NCR 290 (may refer to the NCR 150 in FIG. 1) and one or more UEs 260 (may refer to the one or more UEs 160 in FIG. 1).

[0073] In the scenario of FIG. 2B, the CU 210 may control the DU 230 and the CU220 may control the DU 240. The TRP 270 may be associated with the DU 230 or managed by the DU 230. The TRP 280 may be associated with the DU 240 or managed by the DU 240. The UE 260 may access TRP 270 via the NCR 290 or access the TRP 280 via NCR 290. A beam associated with the TRP 270 may refer to a SSB beam, e.g., a SSBX and a beam associated with the TRP 280 may refer to a further SSB beam, e.g., SSBY.

[0074] In the example scenario 200 A and 200B, the NCR 290 may comprise an NCR MT 292 and an NCR FWD 294. The NCR MT 292 may utilize the same antenna panel(s) as NCR-FWD 294. The NCR MT 292 may be either single connected (SC) or dual connected (DC). Furthermore, the NCR MT 292 may be responsible for NCR configuration, coordination with the CU 210 for multi-TRP operation, and NCR-Fwd control. The TRP control may occur at the RRC, MAC, or PHY (DCI) level.

[0075] Furthermore, the CU 210 or CU 220 may control (on RRC level) a TRP switching in coordination with NCR-MT 292; control the (conditional) handovers of UEs connected via NCR 290; and / or prepare with target gNB CU (in the example scenario 200B) with the UE context for potential re-establishment attempt (enabling successful completion of the re-establishment procedure).

[0076] In addition, the DU 230 or DU 240 may run RLC / MAC protocols for TRP(s) and Provides PHY configuration and control of TRP(s). Moreover, the DU 230 or DU 240 may manage lower layer (non-RRC) control for NCR-MT 292 and perform information exchange with the CU 210 or CU 220 about the status of NCR 290 and TRPs.

[0077] FIG. 2C illustrates an example scenario 200C of TRPs served by the same CU and same DU. The example scenario 200C is generally consistent with the examplescenario 200A, except that two TRPs are controlled by one DU. Specifically, in the scenario of FIG. 2C, the CU 210 may control the DU 230. The TRP 270 may be associated with the DU 230 or managed by the DU 230. Similarly, the TRP 280 may be associated with the DU 230 or managed by the DU 230.

[0078] Now reference is made to FIG. 3, which illustrates a signaling chart of an example procedure 300 for a TRP change in a relay operation according to some example embodiments of the present disclosure. The example procedure 300 involves multiple devices, such as the CU 210, the DU 230, the DU 240, the TRP 270, the TRP 280, the NCR 290, a UE 260-1 and a UE 260-2. The example procedure 300 may be implemented in the example scenario shown in FIG. 2A where the UEs 260-1 and 260-2 are specific examples of the UEs 260. The procedure 300 may be described with reference to FIG. 2A.

[0079] During the procedure 302, the NCR 290 may connect, e.g., in single connected manner, to the CU 210 via the TRP 270 and the DU 230, thereby the UE 260-1 may connect with CU 210 via the NCR 290. That is, the starting point is where NCR 290 BH is for the TRP 270.

[0080] In some scenarios, the link quality is degrading indicating need to change to TRP 280. It is also possible that the load increasing on the TRP 270 may also lead to a TRP change and therefore a load balancing is required between TRPs.

[0081] Alternatively, the CU 210 may initiate the TRP change, based on load on the TRP links, change in the network topology, or the like. It is to be understood that the TRP change may also be triggered by any other possible event or conditions.

[0082] In case of degraded radio conditions, NCR 290 (e.g., NCR-MT 292) may send (308) a measurement report triggered by an event appropriate for NCR operation. The new TRP (e.g., TRP 280) can be selected based on the NCR-MT measurement report. Based on the measurement report, the CU 210 may prepare DU 240 / TRP 280 so that the cell / beam configuration is suitable for the relaying i.e. providing the forward link to be amplified by the NCR 290 after the TRP change. That is, the CU 210 may configure DU 240 / TRP 280 for the NCR support.

[0083] During the preparation phase of the NCR operation, the CU 210 transmits (310) to the DU 240 and further to TRP 280, a configuration of a preparation of a relay operation associated with the NCR 290 for the DU 240.

[0084] In some example embodiments, the configuration of the preparation is transmitted to from the CU 210 the DU 240 via a Fl message. In this way, related signaling happens over Fl connection between the CU 210 and the DU 240 to control the TRP 280.

[0085] In some other example embodiments, the configuration of the preparation may be considered as or indicated by one or more new IES in an Fl message or in an Fl application protocol (AP) message. In other words, the configuration may be carried in a new message or Fl procedure, or new IE in one of the existing Fl AP messages.

[0086] In some example embodiments, the configuration may include a cell identifier associated with the TRP change. For example, a physical cell ID (PCI) for the TRP changes.

[0087] Alternatively, or additionally, the configuration may include one or more beams configured for the forward link of the relay operation, or synchronization signal and physical broadcast channel block (SSB) configuration for the selected beams. It is to be understood that other relevant beam related configurations may be included, such as reservations for access resources, transmit (TX) power, etc.

[0088] It is to be understood that the configuration of a preparation of a relay operation may be different from the DU configuration for the UE handover (HO), because the configuration is for the forward link of the relay operation to be used by all UEs connected via the NCR access link. The configuration is therefore non-UE-associated.

[0089] Then an acknowledgment for the preparation of the relay operation may be transmitted (314) from TRP 280 / DU 240 to the CU 210. The preparation acknowledgment may have an additional configuration, e.g., lower layer configuration managed by DU 240. For example, the additional configuration may comprise one or more related configurations received by the DU 240 from Operations, Administration, and Maintenance (0AM). As other example, the DU 240 may connect 0AM during the preparation phase to download required configurations.

[0090] Upon receiving the acknowledgment, the CU 210 transmits (318), to the NCR, a configuration for establishing the forward link between the UE 260-1 and the TRP 280 / DU 240. This configuration may be sent over a C-link to NCR-MT which is controlling the Fwd-path within the NCR. The C-link remains on the source link to carry some messages (e.g., Conditional HO (CHO) commands) to the UE 260-1.

[0091] In some example embodiments, the configuration for establishing the forward link may be indicated by one or more new IES in a RRC signaling.

[0092] The CU 210 may transmit (320) a CHO configuration to the UE 260-1 to configure one or more event for triggering the CHO. Thus, UEs supporting CHO may be configured for CHO with the target cell / beam(s) prepared for the TRP 280.

[0093] The CU 210 transmit (322), to the NCR 290, an indication that the relay operation associated with the NCR 290 is to be changed to the TRP 280. In this way, the CU 210 may instruct the NCR 290 to switch the forward link from TRP 270 to the configured cell / beam(s) on TRP 280.

[0094] During the procedure 324, the NCR 290 may keep the control link (C-link) active with TRP 270 upon receiving the indication of TRP change. This is done to enable a possible fallback option, allowing the NCR to revert back to the previous configuration and be served by the TRP 270 if needed. By maintaining the C-link with TRP 270 during the forward link switch to TRP 280, the NCR 290 ensures seamless transition and flexibility in its network connectivity.

[0095] In some example embodiments, the CU 210 may transmit (326) an indication for terminating the forward link between the UE 260-1 and the TRP 270 after establishing the forward link between the UE 260-1 and the TRP 280 successfully.

[0096] As described above, UEs connected via the NCR 290 are configured for the CHO. Only the UEs supporting CHO may perform the CHO based on the configuration obtained from the CU 210. In this CHO, the target cell / beam is what has been configured for the TRP 280.

[0097] If the UE 260-1 is capable of CHO capability, if the UE 260-1 determines (330) that the CHO triggering event is fulfilled, the UE 260-1 may perform the CHO and transmit (332) an indication of HO completion to the CU 210 via TRP 280 / DU 240. In this situation, The CHO event is triggering the CHO execution of the UE 260-1 as the TRP 270 signals are no longer forwarded by NCR 290. The UE 260-1 may proceed with normal CHO procedure by accessing the target cell and sending HO complete message.

[0098] If the UE 260-1 is incapable of CHO capability, the UE 260-2 may experience radio link failure (RLF) after the TRP switch. As a result, the UE 260-2 may detect the RLF and proceed with the re-establishment attempt after RLF. It is highly likely that theNCR access link will remain the optimal choice, and the beam(s) / cell of TRP 280 will be the strongest and selected for re-establishment. These UEs will access the new cell / beam and send a re-establishment request message.

[0099] Specifically, the UE 260-2 transmits (338) a RRC re-establishment request to the CU 210. The CU 210 transmits (344) an indication of RRC re-establishment (successful re-establishment) to the UE 260-2. Then, the UE 260-2 transmits (350) a RRC re-establishment complete message to the CU 210.

[0100] The CU 210 moves the control link to TRP 280 by transmitting (356) a HO command to the NCR 290. The NCR 290 is handed over to the TRP 280 in case the cell is changed and the C-link is therefore moved to the new cell, e.g., associated with the TRP 280. The NCR 290 then transmits (364) a HO complete message to the CU 210. The normal HO procedure can be used in this case. The timing of the HO and its relation to the TRP switch of the forward link can vary, as different implementation options are available.

[0101] During the procedure 370, the NCR 290 may connect, e.g., in single connected manner, to the CU 210 via the TRP 280 and the DU 240.

[0102] In the procedure 300, if the cell is not changed, the NCR 290 may change the beam for the control link, which may be handled by the serving CU, i.e., CU 210.

[0103] In this case, the change in forward signals triggers either CHO or RLF detection, which initiates the access procedure towards the target cell / beam(s) on TRP 280. The CHO execution or the re-establishment procedure may be successfully completed as the UE contexts are available at the CU 210.

[0104] The C-link of the NCR 290 can be changed to TRP 280 either by changing beams within the same cell or by performing a HO procedure if the cell on TRP 280 is different from TRP 270. The timing of the C-link change in relation to the forward link switch can vary and may be implementation- specific, allowing for flexibility and optimization in the network.

[0105] It is to be understood that the procedure described with FIG. 3 may also be used for the scenario shown in FIG. 2C, in which the TRP 270 and TRP 280 may be controlled by a single DU.

[0106] FIG. 4 illustrates a signaling chart of another example procedure 400 for a TRPchange in a relay operation according to some example embodiments of the present disclosure. The example procedure 400 involves multiple devices, such as the CU 210, the CU 220, the DU 230, the DU 240, the TRP 270, the TRP 280, the NCR 290, and the UE 260-1. The following will describe with reference to FIG. 2B.

[0107] FIG. 4 illustrates a scenario where the source DU (e.g., DU 230) and the target DU (e.g., DU 240) are managed by different CUs. The DU 230 providing the TRP 270 is managed by CU 210 and the DU 240 providing the TRP 280 is managed by CU 220.

[0108] In comparison to the single CU scenario, there are additional elements involved in inter-CU (Xn AP) signaling. Prior to initiating the TRP change, the source CU (e.g., CU 210) may negotiate with neighboring CUs (e.g., CU 220) regarding their support for NCR 290. This negotiation can also occur when the need for TRP change is indicated, such as after receiving the NCR-MT measurement report from the NCR 290. Advance negotiation could however be safer as potential targets are already known when the TRP change is triggered shortening the latencies and reaction time.

[0109] The configuration of the target TRP (e.g., TRP 280) is initiated through a request from the source CU (e.g., CU 210). This process may be TRP / DU-associated instead of UE associated. Hence, new messages are required for the target TRP configuration. During the execution of the TRP switch, the HO request for connected UEs have to be sent over Xn but that can use legacy signaling. The procedure 400 may be described with reference to FIG. 2B.

[0110] In a procedure 402, the NCR 290 may connect, e.g., in single connected manner, to the CU 210 via the TRP 270 and the DU 230, thereby the UE 260-1 may connect with CU 210 via the NCR 290. That is, the starting point is where NCR 290 BH is for the TRP 270.

[0111] During the procedure 404, if a TRP change is determined, a negotiation for a usage of the relay operation for the TRP 280 is established between the CU 210 and CU 220. Then the CU 210 transmits (406) a request to move NCR 290 control from the TRP 270 to the TRP 280.

[0112] During the preparation phase of the NCR operation, the CU 220 transmits (408) to the DU 240 and further to TRP 280, a configuration of a preparation of a relay operation associated with the NCR 290 for the DU 240.

[0113] In some example embodiments, the configuration of the preparation is transmitted to from the CU 220 the DU 240 via a Fl message. In this way, related signaling happens over Fl connection between the CU 220 and the DU 240 to control the TRP 280.

[0114] In some other example embodiments, the configuration of the preparation may be considered as or indicated by one or more new IES in an Fl message or in an Fl application protocol (AP) message. In other words, the configuration may be carried in a new message or Fl procedure, or new IE in one of the existing Fl AP messages.

[0115] In some example embodiments, the configuration may include a cell identifier associated with the TRP change. For example, a physical cell ID (PCI) for the TRP changes.

[0116] Alternatively, or additionally, the configuration may include one or more beams configured for the forward link of the relay operation, or synchronization signal and physical broadcast channel block (SSB) configuration for the selected beams. It is to be understood that other relevant beam related configurations may be included, such as reservations for access resources, transmit (TX) power, etc.

[0117] Then an acknowledgment for the preparation of the relay operation may be transmitted (412) from TRP 280 / DU 240 to the CU 220. The preparation acknowledgment may have an additional configuration, e.g., lower layer configuration managed by DU 240.

[0118] The CU 210 transmits (416), to the NCR 290, a measurement configuration, for example, priority on the TRP 280. During the procedure 402, the NCR may detect a degradation of the link of TRP 270 and / or the TRP 280 has a better link quality. In this case, the NCR 290 determines a TRP change to the TRP 280 is to be initiated for the UE 260-1, and then transmits (420) a measurement report triggered by an event appropriate for NCR operation.

[0119] Then the CU 210 transmits (422) an NCR configuration for the TRP 280, for establishing the forward link between the UE 260-1 and the TRP 280 / DU 240.

[0120] In an inter-CU scenario, a request is sent from the source CU to the target CU for the configuration of TRP 280. The target CU generates the configuration and sends it first to the source CU which transfer it to NCR in an RRC signaling.

[0121] There may be several steps between the CUs. For example, the CU 210 transmits (424) a HO request of UE 260-1 to the CU 220. The CU 220 transmits (426) a HO requestacknowledgement to the CU 210.

[0122] A context of the UE 260-1 may be required by the CU 220 for the TRP change. For example, the CU 210 transmits (428) the context of the UE 260-1 to the CU 220.

[0123] In some example embodiments, the CU 210 may transmit, to the UE 260-1, a conditional handover (CHO) configuration associated with the TRP change. The CHO configuration at least indicates at least one trigger for the CHO and the configuration of the TRP 280 associated with the DU 240 for the TRP change.

[0124] In some example embodiments, the CU 210 may prepare the TRP 280 associated with the DU 240 for the TRP change to enable access of the UE 260-1.

[0125] In this way, if the UE 260-1 supports CHO, the CHO preparation and configuration is needed. If the UE 260-1 does not support CHO, the CU 220 may be prepared with the UE context so that the re-establishment attempt can be successful.

[0126] After that, an acknowledgment for the preparation of the relay operation may be transmitted (430) from CU 220 to the CU 210.

[0127] The CU 210 transmits (432) a CHO configuration to the UE 260-1 and transmit (434) an indication of TRP switch to the NRC 290. In this way, the CU 210 may instruct the NCR 290 to switch the forward link from TRP 270 to the configured cell / beam(s) of TRP 280.

[0128] During the procedure 436, the NCR 290 may keep the control link (C-link) active with TRP 270. This would be done to enable a possible fallback option, allowing the NCR 290 to revert back to the previous configuration and be served by the TRP 270 if needed.

[0129] In some cases, the CU 210 transmits (438) an indication for terminating the forward link between the UE 260-1 and the TRP 270 after an establishment of the forward link between the UE 260-1 and the TRP 280.

[0130] In the case of UEs with CHO capability, the DU 240 which is controlled by the CU 220, will be prepared for the UE access to enable successful CHO execution. In the case of UEs without CHO capability or not configured for CHO, the CU 220 is prepared with the UE contexts of all UEs to enable successful re-establishment after RLF. Once the UEs have sent re-establishment request via the target TRP 280, the CU 220 can send the re-establishment message to the UEs. The UEs may response re-establishment completemessage, indicating the completion of the procedure.

[0131] According to the embodiments described above, the procedure enables UEs to maintain their connection despite sudden changes in the served cell / beam(s) on the NCR access link. This ensures uninterrupted connectivity for UEs, even when encountering such changes. The network control is maintained throughout the procedure, allowing for effective management of UE behavior in these scenarios. This is achieved even when UEs have no knowledge of the NCR deployment and only support legacy features, ensuring compatibility and seamless operation.

[0132] FIG. 5 shows a flowchart of an example method 500 implemented at a device in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the method 500 will be described from the perspective of the first CU 110 in FIG. 1.

[0133] At block 510, the first CU 110 determines that a TRP change for the backhaul link of a relay device is to be initiated.

[0134] At block 520, the first CU 110, based on the determination, transmits, to a distributed network node controlled by the first CU 110, a configuration of a preparation of a relay operation associated with the relay device for the distributed network node. A forward link associated with the relay operation is to be established between a user device and a TRP associated with the distributed network node for the TRP change.

[0135] In some example embodiments, the first CU 110 transmits the configuration to the distributed network node via a Fl message.

[0136] In some example embodiments, the first CU 110 transmits the configuration to the distributed network node via an Fl message or via an Fl application protocol, AP, message, wherein the configuration is indicated by one or more information elements of the Fl AP message.

[0137] In some example embodiments, the configuration comprises at least one of the following: a cell identifier associated with the TRP change, one or more beams configured for the forward link of the relay operation, or synchronization signal and physical broadcast channel block, SSB, configuration for the one or more beams.

[0138] In some example embodiments, the first CU 110 receives, from the distributed network node, an acknowledgment for the preparation of the relay operation with anadditional configuration associated with the preparation obtained by the distributed network node.

[0139] In some example embodiments, the first CU 110 transmits, to the relay device, a configuration for establishing the forward link between the user device and the TRP associated with the distributed network node for the relay operation.

[0140] In some example embodiments, the configuration is indicated by one or more IES in a RRC signaling.

[0141] In some example embodiments, the first CU 110 transmits, to the relay device, an indication that the relay operation associated with the relay device is to be changed to the TRP associated with the distributed network node for the TRP change.

[0142] In some example embodiments, the first CU 110 transmits, to a further distributed network node, an indication for terminating a further forward link between the user device and a further TRP associated with the further distributed network node after an establishment of the forward link between the user device and the TRP associated with the distributed network node.

[0143] In some example embodiments, the first CU 110, based on the determination, transmits, to a further centralized network node, a request associated with the relay operation for supporting the TRP change, to negotiate with the further centralized network node for a usage of the relay operation for the TRP associated with the distributed network node.

[0144] In some example embodiments, the first CU 110 transmits, to a user device, a CHO configuration associated with the TRP change, wherein the CHO configuration at least indicating at least one trigger for the CHO and the configuration of the TRP associated with the distributed network node for the TRP change.

[0145] In some example embodiments, the first CU 110 prepare the TRP associated with the distributed network node for the TRP change to enable access of the user device.

[0146] In some example embodiments, the first CU 110 comprises a centralized network node and the relay device comprises a network-controlled repeater associated with the relay operation.

[0147] FIG. 6 shows a flowchart of an example method 600 implemented at a device inaccordance with some example embodiments of the present disclosure. For the purpose of discussion, the method 600 will be described from the perspective of the second CU 120 in FIG. 1.

[0148] At block 610, the second CU 120, during a TRP change for the backhaul link of a relay device, transmits, to a relay device, an indication that a relay operation associated with the relay device is to be changed to a TRP associated with a distributed network node for the TRP change. A forward link associated with the relay operation is to be established between the user device and the TRP during the TRP change. The distributed network node is controlled by a further centralized network node other than the first CU 110.

[0149] In some example embodiments, second CU 120 transmits, to a further distributed network node controlled by the second CU 120, an indication for terminating a further forward link between the user device and a further TRP associated with the further distributed network node after an establishment of the forward link between the user device and the TRP associated with the distributed network node.

[0150] In some example embodiments, the second CU 120 receives, from the further centralized network, a request associated with the relay operation for supporting the TRP change, to negotiate with the further centralized network node for a usage of the relay operation for the TRP associated with the distributed network node.

[0151] In some example embodiments, the second CU 120 comprises a centralized network node and the relay device comprises a network-controlled repeater associated with the relay operation.

[0152] FIG. 7 shows a flowchart of an example method 700 implemented at a device in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the method 700 will be described from the perspective of the second DU 140 in FIG. 1.

[0153] At block 710, the second DU 140 receives, from a centralized network node, a configuration of a preparation of a relay operation associated with a relay device for the second DU 140. A forward link associated with the relay operation is to be established between a user device and a TRP associated with the second DU 140 for a TRP change for the backhaul link of the relay device.

[0154] At block 720, the second DU 140 causes, based on the configuration, the forwardlink associated with the relay operation to be established between the user device and the TRP associated with the second DU 140 during the TRP change.

[0155] In some example embodiments, the second DU 140 receives the configuration from the centralized network node via a Fl message.

[0156] In some example embodiments, the second DU 140 receives the configuration from the centralized network node via a Fl AP message, wherein the configuration is indicated by one or more information elements of the Fl AP message.

[0157] In some example embodiments, the configuration comprises at least one of the following: a cell identifier associated with the TRP change, one or more beams configured for the forward link of the relay operation, or synchronization signal and physical broadcast channel block, SSB, configuration for the one or more beams.

[0158] In some example embodiments, the second DU 140 transmits, to the centralized network node, an acknowledgment for the preparation of the relay operation with an additional configuration associated with the preparation obtained by the second DU 140.

[0159] In some example embodiments, the second DU 140 comprises a distributed network node and the relay device comprises a network-controlled repeater associated with the relay operation.

[0160] FIG. 8 shows a flowchart of an example method 800 implemented at a device in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the method 800 will be described from the perspective of the NCR 150 in FIG. 1.

[0161] At block 810, the NCR 150 receives, from a centralized network node, an indication that a relay operation associated with the NCR 150 is to be changed from a TRP to associated with a distributed network node to a further TRP associated with the distributed network node or a further distributed network node for a TRP change for the backhaul link of the relay device. A forward link associated with the relay operation is to be established between the user device and the further TRP during the TRP change.

[0162] At block 820, the NCR 150 establishes, based on the indication, the forward link between the user device and the further TRP during the TRP change.

[0163] In some example embodiments, the NCR 150 receives, from the centralizednetwork node, a configuration for establishing the forward link between the user device and the TRP associated with the distributed network node for the relay operation.

[0164] In some example embodiments, the configuration is indicated by one or more IES in a RRC signaling.

[0165] In some example embodiments, the NCR 150 keeps a control link associated with TRP before a completion of the TRP change.

[0166] In some example embodiments, the NCR 150 comprises a network-controlled repeater associated with the relay operation.

[0167] In some example embodiments, a first apparatus capable of performing any of the method 500 (for example, the first CU 110 in FIG. 1) may comprise means for performing the respective operations of the method 500. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module. The first apparatus may be implemented as or included in the first CU 110 in FIG. 1.

[0168] In some example embodiments, the first apparatus comprises means for determining that a TRP change for the backhaul link of a relay device is to be initiated; and means for based on the determination, transmitting, to a distributed network node controlled by the apparatus, a configuration of a preparation of a relay operation associated with the relay device for the distributed network node, wherein a forward link associated with the relay operation is to be established between a user device and a TRP associated with the distributed network node for the TRP change.

[0169] In some example embodiments, the first apparatus further comprises: means for transmitting the configuration to the distributed network node via a Fl message.

[0170] In some example embodiments, the first apparatus further comprises: means for transmitting the configuration to the distributed network node via a Fl AP message, wherein the configuration is indicated by one or more information elements of the Fl AP message.

[0171] In some example embodiments, the configuration comprises at least one of the following: a cell identifier associated with the TRP change, one or more beams configured for the forward link of the relay operation or synchronization signal and physical broadcast channel block, SSB, configuration for the one or more beams.

[0172] In some example embodiments, the first apparatus further comprises: means for receiving, from the distributed network node, an acknowledgment for the preparation of the relay operation with an additional configuration associated with the preparation obtained by the distributed network node.

[0173] In some example embodiments, the first apparatus further comprises: means for transmitting, to the relay device, a configuration for establishing the forward link between the user device and the TRP associated with the distributed network node for the relay operation.

[0174] In some example embodiments, the configuration is indicated by one or more IES in a RRC signaling.

[0175] In some example embodiments, the first apparatus further comprises: means for transmitting, to the relay device, an indication that the relay operation associated with the relay device is to be changed to the TRP associated with the distributed network node for the TRP change.

[0176] In some example embodiments, the first apparatus further comprises: means for transmitting, to a further distributed network node, an indication for terminating a further forward link between the user device and a further TRP associated with the further distributed network node after an establishment of the forward link between the user device and the TRP associated with the distributed network node.

[0177] In some example embodiments, the first apparatus further comprises: means for based on the determination, transmitting to a further centralized network node, a request associated with the relay operation for supporting the TRP change, to negotiate with the further centralized network node for a usage of the relay operation for the TRP associated with the distributed network node.

[0178] In some example embodiments, the first apparatus further comprises: means for transmitting, to a user device, a CHO configuration associated with the TRP change, wherein the CHO configuration at least indicating at least one trigger for the CHO and the configuration of TRP associated with the distributed network node for the TRP change.

[0179] In some example embodiments, the first apparatus further comprises: means for preparing the TRP associated with the distributed network node for the TRP change to enable access of the user device.

[0180] In some example embodiments, the apparatus comprises a centralized network node and the relay device comprises a network-controlled repeater associated with the relay operation.

[0181] In some example embodiments, the first apparatus further comprises means for performing other operations in some example embodiments of the method 500 or the first CU 110. In some example embodiments, the means comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the performance of the first apparatus.

[0182] In some example embodiments, a second apparatus capable of performing any of the method 600 (for example, the second CU 120 in FIG. 1) may comprise means for performing the respective operations of the method 600. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module. The second apparatus may be implemented as or included in the second CU 120 in FIG. 1.

[0183] In some example embodiments, the second apparatus comprises means for during a TRP change for the backhaul link of a relay device, transmitting, to a relay device, an indication that a relay operation associated with the relay device is to be changed to a TRP associated with a distributed network node for the TRP change, wherein a forward link associated with the relay operation is to be established between the user device and the TRP during the TRP change, and wherein the distributed network node is controlled by a further centralized network node other than the apparatus.

[0184] In some example embodiments, the second apparatus further comprises: means for transmitting, to a further distributed network node controlled by the apparatus, an indication for terminating a further forward link between the user device and a further TRP associated with the further distributed network node after an establishment of the forward link between the user device and the TRP associated with the distributed network node.

[0185] In some example embodiments, the second apparatus further comprises: means for receiving, from the further centralized network, a request associated with the relay operation for supporting the TRP change, to negotiate with the further centralized network node for a usage of the relay operation for the TRP associated with the distributed network node.

[0186] In some example embodiments, the apparatus comprises a centralized network node and the relay device comprises a network-controlled repeater associated with the relay operation.

[0187] In some example embodiments, the second apparatus further comprises means for performing other operations in some example embodiments of the method 600 or the second CU 120. In some example embodiments, the means comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the performance of the second apparatus.

[0188] In some example embodiments, a third apparatus capable of performing any of the method 700 (for example, the second DU 140 in FIG. 1) may comprise means for performing the respective operations of the method 700. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module. The third apparatus may be implemented as or included in the second DU 140 in FIG. 1.

[0189] In some example embodiments, the third apparatus comprises means for receiving, from a centralized network node, a configuration of a preparation of a relay operation associated with a relay device for the apparatus, wherein a forward link associated with the relay operation is to be established between a user device and a TRP associated with the apparatus for the TRP change; and means for causing, based on the configuration, the forward link associated with the relay operation to be established between the user device and the TRP associated with the apparatus during the TRP change.

[0190] In some example embodiments, the third apparatus further comprises: means for receiving the configuration from the centralized network node via a Fl message.

[0191] In some example embodiments, the third apparatus further comprises: means for receiving the configuration from the centralized network node via a Fl AP message, wherein the configuration is indicated by one or more information elements of the Fl AP message.

[0192] In some example embodiments, the configuration comprises at least one of the following: a cell identifier associated with the TRP change, one or more beams configured for the forward link of the relay operation, or synchronization signal and physical broadcast channel block, SSB, configuration for the one or more beams.

[0193] In some example embodiments, the third apparatus further comprises: means for transmitting, to the centralized network node, an acknowledgment for the preparation of the relay operation with an additional configuration associated with the preparation obtained by the apparatus.

[0194] In some example embodiments, the apparatus comprises a distributed network node and the relay device comprises a network-controlled repeater associated with the relay operation.

[0195] In some example embodiments, the third apparatus further comprises means for performing other operations in some example embodiments of the method 700 or the the second DU 140. In some example embodiments, the means comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the performance of the third apparatus.

[0196] In some example embodiments, a fourth apparatus capable of performing any of the method 800 (for example, the NCR 150 in FIG. 1) may comprise means for performing the respective operations of the method 800. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module. The fourth apparatus may be implemented as or included in the NCR 150 in FIG. 1.

[0197] In some example embodiments, the fourth apparatus comprises means for receiving, from a centralized network node, an indication that a relay operation associated with the apparatus is to be changed from a TRP to associated with a distributed network node to a further TRP associated with a distributed network node or a further distributed network node for a TRP change for the backhaul link of the relay device, wherein a forward link associated with the relay operation is to be established between the user device and the further TRP during the TRP change; and means for establishing, based on the indication, the forward link between the user device and the further TRP during the TRP change.

[0198] In some example embodiments, the fourth apparatus further comprises: means for receiving, from the centralized network node, a configuration for establishing the forward link between the user device and the TRP associated with the distributed network node for the relay operation.

[0199] In some example embodiments, the configuration is indicated by one or more IES in a RRC signaling.

[0200] In some example embodiments, the fourth apparatus further comprises: means for keeping a control link associated with TRP before a completion of the TRP change.

[0201] In some example embodiments, the relay device comprises a network-controlled repeater associated with the relay operation. To limit the claim number, we do not draft a claim set for the DU who is associated with a TRP used before the TRP change.

[0202] In some example embodiments, the fourth apparatus further comprises means for performing other operations in some example embodiments of the method 800 or the NCR 150. In some example embodiments, the means comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the performance of the fourth apparatus.

[0203] FIG. 9 is a simplified block diagram of a device 900 that is suitable for implementing example embodiments of the present disclosure. The device 900 may be provided to implement a communication device, for example, the first CU 110, the second CU 120, the second DU 140 or the NCR 150 as shown in FIG. 1. 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.

[0204] The communication module 940 is for bidirectional communications. The communication module 940 has one or more communication interfaces to facilitate communication with one or more other modules or devices. The communication interfaces may represent any interface that is necessary for communication with other network elements. In some example embodiments, the communication module 940 may include at least one antenna.

[0205] The processor 910 may be of any type suitable to the local technical network and may include one or more of the following: general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device 900 may have multiple processors, such as an application specific integrated circuit chip that is slaved in time to a clock which synchronizes the main processor.

[0206] The memory 920 may include one or more non-volatile memories and one ormore volatile memories. Examples of the non-volatile memories include, but are not limited to, a Read Only Memory (ROM) 924, an electrically programmable read only memory (EPROM), a flash memory, a hard disk, a compact disc (CD), a digital video disk (DVD), an optical disk, a laser disk, and other magnetic storage and / or optical storage. Examples of the volatile memories include, but are not limited to, a random access memory (RAM) 922 and other volatile memories that will not last in the power-down duration.

[0207] A computer program 930 includes computer executable instructions that are executed by the associated processor 910. The instructions of the program 930 may include instructions for performing operations / acts of some example embodiments of the present disclosure. The program 930 may be stored in the memory, e.g., the ROM 924. The processor 910 may perform any suitable actions and processing by loading the program 930 into the RAM 922.

[0208] The example embodiments of the present disclosure may be implemented by means of the program 930 so that the device 900 may perform any process of the disclosure as discussed with reference to FIG. 2 to FIG. 8. The example embodiments of the present disclosure may also be implemented by hardware or by a combination of software and hardware.

[0209] In some example embodiments, the program 930 may be tangibly contained in a computer readable medium which may be included in the device 900 (such as in the memory 920) or other storage devices that are accessible by the device 900. The device 900 may load the program 930 from the computer readable medium to the RAM 922 for execution. In some example embodiments, the computer readable medium may include any types of non-transitory storage medium, such as ROM, EPROM, a flash memory, a hard disk, CD, DVD, and the like. The term “non-transitory,” as used herein, is a limitation of the medium itself (i.e., tangible, not a signal) as opposed to a limitation on data storage persistency (e.g., RAM vs. ROM).

[0210] FIG. 10 shows an example of the computer readable medium 1000 which may be in form of CD, DVD or other optical storage disk. The computer readable medium 1000 has the program 930 stored thereon.

[0211] Generally, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Someaspects may be implemented in hardware, and 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 embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representations, it is to be understood that the block, apparatus, system, technique or method described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

[0212] Some example embodiments of the present disclosure also provide at least one computer program product tangibly stored on a computer readable medium, such as a non- transitory computer readable medium. The computer program product includes computerexecutable instructions, such as those included in program modules, being executed in a device on a target physical or virtual processor, to carry out any of the methods as described above. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.

[0213] Program code for carrying out methods of the present disclosure may be written in any combination of one or more programming languages. The program code may be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program code, when executed by the processor or controller, cause the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code may execute entirely on a machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.

[0214] In the context of the present disclosure, the computer program code or related data may be carried by any suitable carrier to enable the device, apparatus or processor to perform various processes and operations as described above. Examples of the carrier include a signal, computer readable medium, and the like.

[0215] The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable medium may include but 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 the computer readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0216] Further, although operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Eike wise, although several specific implementation details are contained in the above discussions, these should not be construed as limitations on the scope of the present disclosure, but rather as descriptions of features that may be specific to particular embodiments. Unless explicitly stated, certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, unless explicitly stated, various features that are described in the context of a single embodiment may also be implemented in a plurality of embodiments separately or in any suitable sub-combination.

[0217] Although the present disclosure has been described in languages specific to structural features and / or methodological acts, it is to be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

WHAT IS CLAIMED IS:

1. An apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to: determine that a transmission-reception point, TRP, change for a backhaul link of a relay device is to be initiated; and based on the determination, transmit, to a distributed network node controlled by the apparatus, a configuration of a preparation of a relay operation associated with the relay device for the distributed network node, wherein a forward link associated with the relay operation is to be established between a user device and a TRP associated with the distributed network node for the TRP change.

2. The apparatus of claim 1, wherein the apparatus is caused to: transmit the configuration to the distributed network node via an Fl message or via an Fl application protocol, AP, message, wherein the configuration is indicated by one or more information elements of the Fl AP message.

3. The apparatus of claim 1 or 2, wherein the configuration comprises at least one of the following: a cell identifier associated with the TRP change, one or more beams configured for the forward link of the relay operation, or synchronization signal and physical broadcast channel block, SSB, configuration for the one or more beams.

4. The apparatus of any of claims 1-3, wherein the apparatus is caused to: receive, from the distributed network node, an acknowledgment for the preparation of the relay operation with an additional configuration associated with the preparationobtained by the distributed network node.

5. The apparatus of claim 1, wherein the apparatus is caused to: transmit, to the relay device, a configuration for establishing the forward link between the user device and the TRP associated with the distributed network node for the relay operation.

6. The apparatus of claim 5, wherein the configuration is indicated by one or more IES in a radio resource control, RRC, signaling.

7. The apparatus of claim 1, wherein the apparatus is caused to: transmit, to the relay device, an indication that the relay operation associated with the relay device is to be changed to the TRP associated with the distributed network node for the TRP change.

8. The apparatus of any of claims 1-7, wherein the apparatus is caused to: transmit, to a further distributed network node, an indication for terminating a further forward link between the user device and a further TRP associated with the further distributed network node after an establishment of the forward link between the user device and the TRP associated with the distributed network node.

9. The apparatus of claim 1, wherein the apparatus is caused to: based on the determination, transmit, to a further centralized network node, a request associated with the relay operation for supporting the TRP change, to negotiate with the further centralized network node for a usage of the relay operation for the TRP associated with the distributed network node.

10. The apparatus of claim 1, wherein the apparatus is caused to: transmit, to a user device, a conditional handover, CHO, configuration associatedwith the TRP change, wherein the CHO configuration at least indicating at least one trigger for the CHO and the configuration of TRP associated with the distributed network node for the TRP change.

11. The apparatus of claim 1, wherein the apparatus is caused to: prepare the TRP associated with the distributed network node for the TRP change to enable access of the user device.

12. The apparatus of any of claims 1-11, wherein the apparatus comprises a centralized network node and the relay device comprises a network-controlled repeater associated with the relay operation.

13. An apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to: during a TRP change for a backhaul link of a relay device, transmit, to a relay device, an indication that a relay operation associated with the relay device is to be changed to a TRP associated with a distributed network node for the TRP change, wherein a forward link associated with the relay operation is to be established between the user device and the TRP during the TRP change, and wherein the distributed network node is controlled by a further centralized network node other than the apparatus.

14. The apparatus of claim 13, wherein the apparatus is caused to: transmit, to a further distributed network node controlled by the apparatus, an indication for terminating a further forward link between the user device and a further TRP associated with the further distributed network node after an establishment of the forward link between the user device and the TRP associated with the distributed network node.

15. The apparatus of claim 13 or 14, wherein the apparatus is caused to: receive, from the further centralized network, a request associated with the relay operation for supporting the TRP change, to negotiate with the further centralized network node for a usage of the relay operation for the TRP associated with the distributed network node.

16. The apparatus of any of claims 13-15, wherein the apparatus comprises a centralized network node and the relay device comprises a network-controlled repeater associated with the relay operation.

17. An apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to: receive, from a centralized network node, a configuration of a preparation of a relay operation associated with a relay device for the apparatus, wherein a forward link associated with the relay operation is to be established between a user device and a TRP associated with the apparatus for a TRP change for a backhaul link of the relay device; and cause, based on the configuration, the forward link associated with the relay operation to be established between the user device and the TRP associated with the apparatus during the TRP change.

18. The apparatus of claim 17, wherein the apparatus is caused to: receive the configuration from the centralized network node via an Fl message or via an Fl application protocol, AP, message, wherein the configuration is indicated by one or more information elements of the Fl AP message.

19. The apparatus of any of claim 17-18, wherein the configuration comprises at least one of the following: a cell identifier associated with the TRP change, one or more beams configured for the forward link of the relay operation, or synchronization signal and physical broadcast channel block, SSB, configuration for the one or more beams.

20. The apparatus of any of claim 17-19, wherein the apparatus is caused to: transmit, to the centralized network node, an acknowledgment for the preparation of the relay operation with an additional configuration associated with the preparation obtained by the apparatus.

21. The apparatus of any of claim 17-20, wherein the apparatus comprises a distributed network node and the relay device comprises a network-controlled repeater associated with the relay operation.

22. An apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to: receive, from a centralized network node, an indication that a relay operation associated with the apparatus is to be changed from a TRP to associated with a distributed network node to a further TRP associated with a distributed network node or a further distributed network node for a TRP change for a backhaul link of the relay device, wherein a forward link associated with the relay operation is to be established between the user device and the further TRP during the TRP change; and establish, based on the indication, the forward link between the user device and the further TRP during the TRP change.

23. The apparatus of claim 22, wherein the apparatus is caused to: receive, from the centralized network node, a configuration for establishing the forward link between the user device and the TRP associated with the distributed network node for the relay operation.

24. The apparatus of any of claims 22-23, wherein the apparatus is caused to: keep a control link associated with TRP before a completion of the TRP change.

25. The apparatus of any of claims 22-24, wherein the relay device comprises a network-controlled repeater associated with the relay operation.

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