WO2025201702A1

WO2025201702A1 - Mac-ce for backhaul procedure

Info

Publication number: WO2025201702A1
Application number: PCT/EP2025/052561
Authority: WO
Inventors: Andrew LAPPALAINEN; Shashika Manosha Kapuruhamy Badalge; Sanjay Goyal; Tero Henttonen
Original assignee: Nokia Technologies Oy
Current assignee: Nokia Technologies Oy
Priority date: 2024-03-27
Filing date: 2025-01-31
Publication date: 2025-10-02
Anticipated expiration: 2026-09-27
Also published as: GB202404354D0; GB2639886A

Abstract

Example embodiments of the present disclosure are directed to medium access control-control element (MAC-CE) for backhaul procedure. In a method, an apparatus receives, at a mobile termination at the apparatus from a network node, a MAC-CE associated with beam information for a backhaul procedure between one or more transmit/receive points (TRPs) associated with the network node and a forwarding portion at the apparatus. The apparatus applies, based on the MAC-CE, one or more transmission configuration indicator (TCI) states of at least one TCI state set indicated in the MAC-CE for the backhaul procedure in a multiple TRP operation or a single TRP operation.

Description

MAC-CE FOR BACKHAUL PROCEDURE

FIELD

[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 medium access control (MAC) control element (CE) (MAC-CE) for backhaul procedure.

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, a repeater such as a network-controlled repeater (NCR) node (referred to as NCR-node) is required to provide a more cost-effective solution. The NCR-node is a radio frequency (RF) repeater that enables wireless amplifying-and-forwarding functionality in next generation (NG)-radio access network (RAN).

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: receive, at a mobile termination at the apparatus from a network node, a MAC-CE associated with beam information for a backhaul procedure between one or more transmit/receive points (TRPs) associated with the network node and a forwarding portion at the apparatus; apply, based on the MAC-CE, one or more transmission configuration indicator (TCI) states of at least one TCI state set indicated in the MAC-CE for the backhaul procedure in a multiple TRP operation or a single TRP operation.

[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: transmit, to a NCR a MAC-CE associated with beam information for a backhaul procedure between one or more TRPs associated with the apparatus and a forwarding portion at the NCR, wherein the MAC-CE comprises at least one TCI state set comprising one or more TCI states for the backhaul procedure in a multiple TRP operation or a single TRP operation and/or an existence indication indicates whether the MAC-CE is configured with at least one TCI state.

[0005] In a third aspect of the present disclosure, there is provided a method. The method comprises: receiving, at a mobile termination at the apparatus from a network node, a MAC-CE associated with beam information for a backhaul procedure between one or more TRPs, associated with the network node and a forwarding portion at the apparatus; applying, based on the MAC-CE, one or more TCI states of at least one TCI state set indicated in the MAC-CE for the backhaul procedure in a multiple TRP operation or a single TRP operation.

[0006] In a fourth aspect of the present disclosure, there is provided a method. The method comprises: transmitting, to a NCR, a MAC-CE associated with beam information for a backhaul procedure between one or more TRPs associated with the apparatus and a forwarding portion at the NCR, wherein the MAC-CE comprises at least one TCI state set comprising one or more TCI states for the backhaul procedure in a multiple TRP operation or a single TRP operation and/or an existence indication indicates whether the MAC-CE is configured with at least one TCI state.

[0007] In a fifth aspect of the present disclosure, there is provided an apparatus. The apparatus comprises means for receiving, at a mobile termination at the apparatus from a network node, a MAC-CE associated with beam information for a backhaul procedure between one or more TRPs, associated with the network node and a forwarding portion at the apparatus; means for applying, based on the MAC-CE, one or more TCI states of at least one TCI state set indicated in the MAC-CE for the backhaul procedure in a multiple TRP operation or a single TRP operation.

[0008] In a sixth aspect of the present disclosure, there is provided an apparatus. The apparatus comprises means for transmitting, to a network-controlled repeater, NCR, a medium access control -control element, MAC-CE, associated with beam information for a backhaul procedure between one or more transmit/receive points, TRPs, associated with the apparatus and a forwarding portion at the NCR, wherein the MAC-CE comprises at least one transmission configuration indicator, TCI, state set comprising one or more TCI states for the backhaul procedure in a multiple TRP operation or a single TRP operation and/or an existence indication indicates whether the MAC-CE is configured with at least one TCI state.

[0009] In a seventh 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 third aspect.

[0010] In an eighth 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 fourth aspect.

[0011] 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

[0012] Some example embodiments will now be described with reference to the accompanying drawings, where:

[0013] FIG. 1 illustrates an example communication environment in which example embodiments of the present disclosure can be implemented;

[0014] FIG. 2A illustrates an NCR downlink (DL) backhaul link beam indication MAC- CE;

[0015] FIG. 2B illustrates an NCR uplink (UL) backhaul link beam indication MAC-CE;

[0016] FIG. 3 illustrates a signaling flow for MAC-CE for backhaul procedure in accordance with some example embodiments of the present disclosure;

[0017] FIG. 4 illustrates an NCR DL multi-TRP backhaul link beam indication MAC-CE in accordance with some example embodiments of the present disclosure;

[0018] FIG. 5 illustrates an enhanced NCR DL multi-TRP backhaul link beam indication MAC-CE in accordance with some example embodiments of the present disclosure;

[0019] FIG. 6 illustrates an enhanced NCR DL multi-TRP backhaul link beam activation MAC-CE in accordance with some example embodiments of the present disclosure;

[0020] FIG. 7 illustrates a unified NCR backhaul link beam activation MAC-CE in accordance with some example embodiments of the present disclosure;

[0021] FIG. 8 illustrates a flowchart of a method implemented at an apparatus in accordance with some example embodiments of the present disclosure;

[0022] FIG. 9 illustrates a flowchart of another method implemented at an apparatus in accordance with some example embodiments of the present disclosure;

[0023] FIG. 10 illustrates a simplified block diagram of a device that is suitable for implementing example embodiments of the present disclosure; and

[0024] FIG. 11 illustrates a block diagram of an example computer readable medium in accordance with some example embodiments of the present disclosure.

[0025] Throughout the drawings, the same or similar reference numerals represent the same or similar element.

DETAILED DESCRIPTION

[0026] 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.

[0027] 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.

[0028] 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. [0029] 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 element could 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.

[0030] As used herein, “at least one of the following: <a list of two or more elements>” and “at least one of <a list of two or more elements>” 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.

[0031] 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.

[0032] 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.

[0033] 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 a portion 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.

[0034] 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.

[0035] 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), 5.5G, 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.

[0036] 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 as a 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.

[0037] 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.

[0038] 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 a communication, 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.

[0039] FIG. 1 illustrates an example communication environment 100 in which example embodiments of the present disclosure can be implemented. In the communication environment 100, a plurality of communication devices, including a terminal device 150 and a network node 140 (also referred to as a network device), can communicate with each other. In the example of FIG. 1, the terminal device 150 may be a UE and the network node 140 may be a base station serving the UE. As illustrated, the terminal device 150 and the network node 140 may communicate with each other via an apparatus such as an NCR 110 (hereinafter may also be referred to as an NCR-node, a relay device or a smart repeater). The NCR 110 is an RF repeater that enables wireless amplifying-and- forwarding functionality in NG-RAN. The NCR 110 may be capable of receiving and applying side control information from the network node 140 with additional functionality to support the NCR operation.

[0040] In some example embodiments, the NCR 110 includes an NCR mobile termination (MT) unit (NCR-MT) 120 (also referred to as an MT at the NCR 110, an MT at a repeater, or an MT at an apparatus) and an NCR forwarding unit (NCR-Fwd) 130 (also referred to as a forwarding portion at the NCR 110, a forwarding portion at a repeater, an NCR RF Fwd, or a forwarding portion at an apparatus).

[0041] The NCR-MT 120 may be an entity supporting a subset of the UE functionality that communicates with the network node 140 to receive side control information via a control link 122 (also referred to as a C-link) based on the new radio (NR) Uu interface. The NCR-Fwd 130 may be a function performing amplifying-and-forwarding of signals between the network node 140 and the terminal device 150 via the NCR-Fwd backhaul link 134 and NCR-Fwd access link 132, respectively. The NCR-Fwd 130 may support multiple beams towards the terminal device 150. The behavior of the NCR-Fwd 130 may be controlled according to the side control information received from the network node 140. In addition, an access link such as UE access link 136 may be established between the network node 140 and the terminal device 150 via the NCR-Fwd 130.

[0042] In some embodiments, the network node 140 may support one or more TRPs. For example, in multi-TRP operation, a serving cell such as a cell provided by the network node 140 may schedule the terminal device 150 from a plurality of TRPs such as two TRPs, providing better coverage, reliability and/or data rates for transmission channels between the terminal device 150 and the network node 140, such as physical downlink shared channel (PDSCH), physical downlink control channel (PDCCH), physical uplink shared channel (PUSCH), and/or physical uplink control channel (PUCCH).

[0043] There may be two different operation modes to schedule multi-TRP PDSCH transmissions: single-downlink control information (DCI) and multi-DCI. For both modes, control of uplink and downlink operation may be done by physical layer and medium access control (MAC) layer, within the configuration provided by the radio resource control (RRC) layer. In single-DCI mode, the terminal device 150 may be scheduled by the same DCI for both TRPs and in multi-DCI mode, the terminal device 150 is scheduled by independent DCIs from each TRP.

[0044] In some example embodiments, there are two different operation modes for multi- TRP PDCCH: PDCCH repetition and system frame number (SFN) based PDCCH transmission. In both modes, the terminal device 150 may receive two PDCCH transmissions, one from each TRP, carrying the same DCI. In PDCCH repetition mode, the terminal device 150 may receive the two PDCCH transmissions carrying the same DCI from two linked search spaces each associated with a different CORESET. In SFN based PDCCH transmission mode, the terminal device 150 may receive the two PDCCH transmissions carrying the same DCI from a single search space/CORESET using different TCI states.

[0045] For multi-TRP PUSCH repetition, based on indications in a single DCI or in a semi-static configured grant provided over RRC, the terminal device 150 may perform PUSCH transmission of the same contents toward two TRPs with corresponding beam directions associated with different spatial relations. For multi-TRP PUCCH repetition, the terminal device 150 may perform PUCCH transmission of the same contents toward two TRPs with corresponding beam directions associated with different spatial relations.

[0046] For inter-cell multi-TRP operation, for multi-DCI PDSCH transmission, one or more TCI states may be associated with synchronization signal (SS) or physical broadcast channel (PBCH) block (SSB) with a physical cell identity (PCI) different from the serving cell PCI. The activated TCI states can be associated with at most one PCI different from the serving cell PCI at a time.

[0047] It is to be understood that the number of devices and their connections shown in FIG. 1 are only for the purpose of illustration without suggesting any limitation. The communication environment 100 may include any suitable number of devices configured to implementing example embodiments of the present disclosure. It is noted that although illustrated as a network device, the network node 140 may be another device than a network device. Although illustrated as a terminal device, the terminal device 150 may be another device than a terminal device. Although illustrated as an NCR-node, the NCR 110 may be another device than an NCR-node.

[0048] In the following, for the purpose of illustration, some example embodiments are described with the terminal device 150 operating as a UE, the network node 140 operating as a base station and the NCR 110 operating as an NCR-node. However, in some example embodiments, operations described in connection with a terminal device may be implemented at a network node or other device, operations described in connection with a network node may be implemented at a terminal device or other device, and operations described in connection with an NCR-node may be implemented at a network node or other device.

[0049] In some example embodiments, a link from the network node 140 to the terminal device 150 is referred to as a downlink (DL), while a link from the terminal device 150 to the network node 140 is referred to as an uplink (UL). In DL, the network node 140 is a transmitting (TX) device (or a transmitter) and the terminal device 150 is a receiving (RX) device (or a receiver). In UL, the terminal device 150 is a TX device (or a transmitter) and the network node 140 is a RX device (or a receiver).

[0050] 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), 5.5G, 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.

[0051] As described, the single TRP operation and the multiple-TRP operation may be supported by a network node such as a base station in the communication environment. However, in release (Rel)-18, NCR-Fwd backhaul link is based on a single TRP architecture, where the beam used for the backhaul link in the downlink and uplink are controlled based on the NCR Downlink Backhaul Link Beam Indication MAC-CE and NCR Uplink Backhaul Link Beam Indication MAC-CE, respectively, which are indicated by the gNB to the NCR-MT.

[0052] FIG. 2A illustrates an NCR DL backhaul link beam indication MAC-CE 200. The MAC-CE indicates a TCI state identifier (ID) to be applied for the DL backhaul beam at the NCR-Fwd, based on a list of TCI state(s) already known by the NCR-MT via RRC configuration.

[0053] Likewise, for the UL backhaul beam at the NCR-Fwd, an NCR UL backhaul link beam indication MAC-CE 250 is shown in FIG. 2B. The MAC-CE 250 may indicate either a TCI state ID (when the NCR-MT is configured with a unified TCI state configuration) or a sounding reference signal (SRS) resource ID (when NCR-MT does not have unified TCI state configuration).

[0054] For multi-TRP operation, the Enhanced TCI States Activation for UE-specific PDSCH MAC-CE and Unified TCI States Activation MAC-CE were specified in Rel-16 and Rel-17, respectively, which are used by a gNB to activate a set of multiple TCI states at a UE for the DL or for the UL. For example, for the UL, a unified TCI state configuration is used in combination with the Rel-17 MAC-CE. The TCI state to be applied for a corresponding TRP at a given instant is based on DCI, where single and multi-DCI schemes are supported. In the single DCI scheme, the DCI is sent from one TRP and indicates two TCI states to be applied, corresponding to two TRPs. In the multi-DCI scheme, one DCI is sent from each of the two TRPs and indicates the TCI state to be applied for that TRP.

[0055] As an enhancement to NCR, it has been proposed that multi-TRP scenarios may be considered in the backhaul. However, mechanisms to support such multi-TRP schemes have not been discussed. Currently NCR-Fwd supports single TRP operation only.

[0056] In order to solve at least part of the above problems or other potential problems, a solution on MAC-CE for backhaul procedure is proposed. In the solution, an apparatus (such as an NCR) receives, at a mobile termination at the apparatus from a network node, a MAC-CE associated with beam information for a backhaul procedure between one or more TRPs associated with the network node and a forwarding portion at the apparatus. Based on the MAC-CE, the apparatus applies one or more TCI states of at least one TCI state set indicated in the MAC-CE for the backhaul procedure in a multiple TRP operation or a single TRP operation.

[0057] In this way, the backhaul link TCI states or backhaul link beams can be indicated by the MAC-CE for both multiple TRP operation and single TRP operation. That is, both the multiple TRP operation and the single TRP operation can be supported by the forwarding portion at the apparatus such as an NCR-Fwd. By extending the multi-TRP support to the NCR-Fwd backhaul, the backhaul link redundancy in case of signal degradation can be supported. In addition, it can offload traffic from the NCR from one TRP to another in case one TRP becomes congested.

[0058] Example embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.

[0059] FIG. 3 illustrates a signaling flow 300 for MAC-CE for backhaul procedure in accordance with some example embodiments of the present disclosure. The signaling flow 300 involves the NCR 110 (which includes the NCR-MT 120 and the NCR-Fwd 130) and the network node 140 in FIG. 1. For purpose of illustration, the signaling flow 300 will be described with respect to FIG. 1.

[0060] In operation, the network node 140 transmits (310), to the NCR 110, a MAC-CE associated with beam information for a backhaul procedure between one or more TRPs associated with the network node 140 and the NCR-Fwd 130. As used herein, the MAC- CE associated with the beam information may be referred to as a “beam activation MAC- CE” or a “beam indication MAC-CE”. The NCR 110 receives (320) the MAC-CE, for example, at the NCR-MT 120.

[0061] The MAC-CE may include at least one TCI state set including one or more TCI states for the backhaul procedure in a multiple TRP operation or a single TRP operation. As used herein, the MAC-CE including or indicating a TCI state means that the MAC-CE includes or indicates an ID of the TCI state.

[0062] In response to receiving (320) the MAC-CE, the NCR 110 applies (330), based on the MAC-CE, one or more TCI states of the at least one TCI state set indicated in the MAC-CE for the backhaul procedure in a multiple TRP operation or a single TRP operation. For example, the NCR 110 may apply one or more beams corresponding to the one or more TCI states for the backhaul procedure. The backhaul procedure may be associated with a backhaul downlink and/or a backhaul uplink.

[0063] In some example embodiments, the MAC-CE may include an indication indicating whether more than one TCI state is associated with a TCI state set. In the following description, for the purpose of illustration, the indication of more than one TCI state associated with a TCI state set may be referred to as a bit “C”. The bit “C” may be of 1 bit or any other bit width. For the purpose of illustration, in some example embodiments, it is assumed that the bit “C” is of one bit. It is also assumed that the bit “C” being equal to 1 means that the bit “C” is set, and the bit “C” being equal to 0 means that the bit “C” is not set. It is to be understood that the value of the bit “C” may be varied.

[0064] In some example embodiments, the MAC-CE may include a further indication indicating whether a TCI state set is composed of two TCI states or one TCI state. In the following description, for the purpose of illustration, the further indication of TCI states may be referred to as a bit “Ci (i being an integer)”. That is, the further indication may indicate a TCI state set is composed of two TCI states (the bit “Ci” is set) or one TCI state (when the bit “Ci” is not set). The bit “Ci” may be of 1 bit or any other bit width. For the purpose of illustration, in some example embodiments, it is assumed that the bit “Ci” is of one bit. It is also assumed that the bit “Ci” being equal to 1 means that the bit “Ci” is set, and the bit “Ci” being equal to 0 means that the bit “Ci” is not set. It is to be understood that the value of the bit “Ci” may be varied.

[0065] Alternatively, or in addition, in some example embodiments, the MAC-CE may include an existence indication indicating whether the at least one TCI state set including one or more TCI states is configured in the MAC-CE. As used herein, the existence indication may be referred to as a presence bit or bit “P” in the MAC-CE or prefixed to the MAC-CE. The bit “P” may be of 1 bit or any other suitable bit width. For the purpose of illustration, in some example embodiments, it is assumed that the bit “P” is of one bit. It is also assumed that the bit “P” being equal to 1 means that the bit “P” is set, and the bit “P” being equal to 0 means that the bit “P” is not set.

[0066] In some example embodiments, the MAC-CE may include a further indication related to at least one TCI state set. The further indication may indicate that two TCI states associated with each TCI state set are to be used for a backhaul uplink and a backhaul downlink between one or more TRPs associated with the network node 140 and the NCR-Fwd 130. As used herein, such further indication may be referred to as bit “D/U” in the MAC-CE. The bit “D/U may be of 1 bit or any other suitable bit width. For the purpose of illustration, in some example embodiments, it is assumed that the bit “D/U” being equal to 1 means that the bit “D/U” is set, and the bit “D/U” being equal to 0 means that the bit “P” is not set.

[0067] Several example bits in the MAC-CE have been described. It is to be understood that the MAC-CE may include one or more of these bits, or otherwise include other suitable bits for indicating TCI state for the backhaul procedure. The NCR 110 may apply (330), based on the bits in the MAC-CE, one or more TCI states of the at least one TCI state set indicated in the MAC-CE for the backhaul procedure in a multiple TRP operation or a single TRP operation. Further embodiments regarding applying the backhaul procedure based on the MAC-CE will be described with respect to FIG. 4 to FIG. 7. In the following description, it is assumed that the TCI state configuration for the serving cell(s) and the corresponding TCI state IDs are already known at the NCR-MT 120 based on RRC configuration(s).

[0068] In some example embodiments, the NCR 110 may determine whether a TCI state set including two TCI states is obtained from the MAC-CE. If the TCI state set including two TCI states is obtained from the MAC-CE, the NCR 110 may determine that the multiple TRP operation is to be used in the backhaul procedure. In such cases, the NCR 110 may apply beams corresponding the two TCI states for backhaul downlink from two TRPs associated with the network node 140 to the NCR-Fwd 130. Otherwise, if the TCI state set obtained from the MAC-CE includes a single TCI state, the NCR 110 may determine that the single TRP operation is to be used in the backhaul procedure.

[0069] In this way, the MAC-CE can be used to directly switch between the single TRP operation and the multi-TRP operation in the backhaul downlink of the NCR-Fwd 130 by configuring the NCR-Fwd DL backhaul link based on the TCI state ID(s) contained in the MAC-CE.

[0070] In some example embodiments, the MAC-CE may be used for DL multi-TRP backhaul link indication of the NCR 110. In such cases, the MAC-CE may be referred to as NCR downlink multi-TRP backhaul link indication MAC-CE, which may be used simultaneously to activate multi-TRP operation in the NCR-Fwd downlink backhaul link and to indicate the DL TCI state to be applied for the multi-TRP beams.

[0071] FIG. 4 illustrates an NCR DL multi-TRP backhaul link beam indication MAC-CE 400 in accordance with some example embodiments of the present disclosure. The MAC-CE 400 may be composed of an octet (OCT) pair, including an octet 401 (also referred to as Oct 1) and an octet 402 (also referred to as Oct 2). Each of the octet 401 and the octet 402 may include a field of TCI state ID, such as the DL TCI state ID. The field of TCI state ID may be of 7 -bit, or any other suitable bit width. The DL TCI state ID may be corresponding to the beams to be applied for the first and second DL backhaul beams. The OCT 401 and/or the OCT 402 may further include a reserved field (R), as shown.

[0072] Upon reception (320) of the MAC-CE by the NCR-MR 120, the NCR-MT 120 may inform the NCR-Fwd 130 to apply the configuration for the DL backhaul link beams based on the TCI state IDs indicated by the MAC-CE.

[0073] With this embodiment, switching between single-TRP and multi-TRP operation in the NCR-Fwd downlink backhaul link is based on reception of the NCR DL backhaul link beam indication MAC-CE shown in FIG. 2A and the NCR DL multi-TRP backhaul link indication MAC-CE shown in FIG. 4, respectively. In other words, if receiving the MAC-CE 200, the NCR-Fwd 130 may apply the single-TRP in the NCR-Fwd downlink backhaul link. If receiving the MAC-CE 400, the NCR-Fwd 130 may apply the multiple- TRP in the NCR-Fwd downlink backhaul link.

[0074] In some example embodiments, the MAC-CE may include an indication such as bit “C” indicating whether the multiple TRP operation is to be used in the backhaul procedure. The NCR 110 may obtain the indication from the MAC-CE. For example, the indication may be one or more bits in an OCT.

[0075] In some example embodiments, if the indication indicates that the multiple TRP operation is to be used in the backhaul procedure and a TCI state set including two TCI states is obtained from the MAC-CE, the NCR 110 may apply beams corresponding the two TCI states for backhaul downlink between two TRPs associated with the network node 140 and the NCR-Fwd 130.

[0076] Otherwise, if the indication indicates that the multiple TRP operation is not to be used in the backhaul procedure and a TCI state set including a TCI state is obtained from the MAC-CE, the NCR 110 may determine that the single TRP operation is to be used in the backhaul procedure. The NCR 110 may apply a beam corresponding to the TCI state for backhaul downlink between the network node 140 and the NCR-Fwd 130. In this way, the indication in the MAC-CE can be used for switching between the single TRP operation and the multi-TRP operation in the backhaul downlink of the NCR-Fwd 130.

[0077] As used herein, the MAC-CE including the indication indicating whether the multiple TRP operation is to be used may be referred to as an enhanced NCR DL backhaul link beam indication MAC-CE. FIG. 5 illustrates an example of an enhanced NCR DL backhaul link beam indication MAC-CE 500, which may be used to switch between single and multi-TRP operation in the NCR-Fwd backhaul link and simultaneously indicates the DL TCI state to be applied for the single-TRP or multi-TRP beam(s).

[0078] As depicted, the MAC-CE 500 is composed of an octet pair including an octet 501 (also referred to as Oct 1 or the first octet) and an octet 502 (also referred to as Oct 2 or the second octet). In the octet 501, one bit (labelled “C” in FIG. 5) may be used to switch between single- and multi-TRP operation. That is, the bit may be used as an indication indicating whether the multiple TRP operation is to be used.

[0079] In some example embodiments, if the bit “C” is set, the length of the MAC-CE may be two octets and the MAC-CE 500 may indicate that the NCR-Fwd 130 may apply multi-TRP operation in the backhaul. For example, if the bit “C” is equal to 1, the bit “C” is set. The remaining bits such as remaining 7 bits in the octet 501 may provide the TCI state indication corresponding to the beam of the first TRP and 7 bits in the octet 502 may be used to provide the TCI state indication corresponding to the beam of the second TRP. [0080] If the bit “C” is not set, the length of the MAC-CE may be one octet (i.e. the octet 502 is not transmitted) and the MAC-CE 500 indicates that the NCR-Fwd 130 may apply single-TRP operation in the backhaul; and the remaining 7 bits in the octet 501 may provide a TCI state indication for the beam corresponding to the (single) TRP. For example, if the bit “C” is equal to 0, the bit “C” is not set.

[0081] In some example embodiments, if the value of the “C” bit changes between successive MAC-CE indications, then the NCR-Fwd 130 backhaul may be switched between multiple TRP operation and single-TRP operation. If the value of the “C” bit does not change, then the respective multiple TRP or single-TRP operation is maintained in the NCR-Fwd 130 backhaul and only the TCI state(s) for the beam(s) are changed.

[0082] Upon reception of the MAC-CE 500 by the NCR-MT 120, the NCR-MT 120 may inform the NCR-Fwd 130 to apply the configuration for the DL backhaul link beams according to the TCI state ID(s) indicated in the MAC-CE 500.

[0083] Alternatively, in some embodiments, if the indication indicates that the multiple TRP operation is to be used in the backhaul operation and a TCI state set including a TCI state is obtained from the MAC-CE, the NCR 110 may determine a reference TCI state that is currently used by the NCR-MT 120. The NCR 110 may apply a first beam corresponding the TCI state and a second beam corresponding to the reference TCI state for backhaul downlink between two TRPs associated with the network node 140 and the NCR-Fwd 130.

[0084] In other words, if the NCT-MT 120 is in single TRP operation and receives the MAC-CE including the indication such as the bit “C” being set and a single TCI state ID, the NCT-MT 120 may inform the NCR-Fwd 130 to apply the multi-TRP operation in the DL backhaul, where the TCI configuration of the first NCR-Fwd DL backhaul beam is the same TCI configuration as the NCR-MT 120 and the TCI configuration of the second NCR-Fwd DL backhaul beam corresponds to the TCI state ID indicated by the MAC-CE. That is, the octet 502 in the MAC-CE may be omitted. If the bit “C” in the octet 501 is set and the octet 502 is removed, a beam corresponding to the TCI state indicated by the TCI state ID in the octet 501 and a beam corresponding to the reference TCI state currently used by the NCR-MT 120 may be applied for the backhaul downlink between two TRPs associated with the network node 140 and the NCR-Fwd 130.

[0085] Alternatively, or in addition, in some example embodiments, the MAC-CE may include an existence indication indicating whether the at least one TCI state set including one or more TCI states is configured in the MAC-CE. The NCR 110 may obtain the existence indication from the MAC-CE. If the NCR 110 determines, based on the existence indication, that the at least one TCI state set including one or more TCI states is configured in the MAC-CE, the NCR 110 may apply the one or more TCI states for the backhaul procedure in the multiple TRP operation or the single TRP operation.

[0086] By way of example, another octet containing a presence bit such as bit “P” may be prefixed to the MAC-CE 500. For example, the remaining bits of the prefixed octet may contain other information relevant to the operation of the NCR-Fwd 130 backhaul, which will not be described here. If the bit “P” is set, for example, the bit “P” being equal to 1, the behavior at the NCR-MT 120 and the NCR-Fwd 130 may be based on the content of the MAC-CE 500 as described above.

[0087] If the bit “P” is not set, for example, the bit “P” being equal to 0, no TCI state ID may be indicated in the MAC-CE. Upon reception of the MAC-CE with the bit “P” not set by the NCR-MT 120, the NCR-MT 120 may inform the NCR-Fwd 130 to apply the same TCI state configuration for the DL backhaul link beam(s) as the one which is already activated at the NCR-MT 120. In other words, if NCR-MT 120 is configured with multi- TRP operation, NCR-Fwd 130 may also use multi-TRP operation following the same TCI configuration as the NCR-MT 120. If the NCR-MT 120 is configured with single-TRP operation, the NCR-Fwd 130 may also use single-TRP operation following the same TCI configuration as the NCR-MT 120.

[0088] In some embodiments, a plurality of TCI state sets is indicated in the MAC-CE for the backhaul procedure. For example, the MAC-CE may contain a set of one or more codepoints (composed of TCI states) to be be activated for the NCR-Fwd backhaul configuration. The network node 140 may transmit, via DCI, an indication indicating a target TCI state set to be applied for the backhaul procedure. The NCR 110 may receive the indication from the network node 140 via DCI. As used herein, the indication via DCI may be referred to as a “DCI indication”. For example, the indication may be an index or ID of the target TCI state set in the plurality of TCI states sets. That is, the DCI indication may be used to indicate codepoint(s) to be applied in the backhaul from among the codepoints activated by MAC-CE indication.

[0089] In some example embodiments, each TCI state set in the plurality of TCI state sets is corresponding to a codepoint. The target TCI state set to be applied for the backhaul procedure may be indicated in the DCI by a target codepoint corresponding to the target TCI state set. For example, the DCI or DCI indication may be an index or ID of the target TCI state set of the plurality of TCI state sets. The NCR 110 may select the target TCI state set from the plurality of TCI state sets based on the indication.

[0090] In some example embodiments, each codepoint of the MAC-CE contains either one or two DL TCI state IDs. The DCI may indicate one codepoint from among the codepoints activated by MAC-CE. If the indicated codepoint has two DL TCI state IDs in the MAC-CE, the NCR-MT 120 may apply the configuration for multi-TRP operation for the NCR-Fwd backhaul downlink according to the corresponding TCI state IDs of the respective codepoint of the MAC-CE. If the indicated codepoint has one DL TCI state ID in the MAC-CE, the NCR-MT 120 may apply the configuration for single-TRP operation for the NCR-Fwd backhaul downlink according to the corresponding TCI state ID of the respective codepoint of the MAC-CE.

[0091] As mentioned, a further indication such as bit “Ci” in the MAC-CE may indicate whether two TCI states are associated with the target TCI state set. If the NCR 110 determines that the further indication related to the target TCI state set such as bit “Ci” indicates that two TCI states are associated with the target TCI state set, the NCR 110 may determine that the multiple TRP operation is to be used in the backhaul procedure. The NCR 110 may apply beams corresponding the two TCI states for backhaul downlink between two TRPs associated with the network node 140 and the NCR-Fwd 130. The further indication may be included in the MAC-CE.

[0092] If the NCR 110 determines that the further indication associated with the target TCI state set indicates that a TCI state is associated with the target TCI state set, the NCR 110 may determine that the single TRP operation is to be used in the backhaul procedure. The NCR 110 may apply a beam corresponding to the TCI state for backhaul downlink between the network node 140 and the NCR-Fwd 130.

[0093] The MAC-CE may be used to activate a set of single-TRP and/or multi-TRP TCI state IDs for the NCR-Fwd DL backhaul link, while the DCI indication may be used to indicate which of the activated TCI states IDs may be applied for the single-TRP or multi- TRP beam(s).

[0094] As used herein, the MAC-CE including a plurality of TCI state sets may be referred to as an “enhanced NCR downlink backhaul link beam activation MAC-CE”. FIG. 6 illustrates an example of the enhanced NCR downlink backhaul link beam activation MAC-CE 600. The MAC-CE 600 may be applied in combination with a DCI indication. As shown, the MAC-CE 600 includes a codepoint 610 (also referred to as a codepoint 1), ..., and a codepoint 620 (also referred to as a codepoint N, N being an integer greater than 1). That is, the MAC-CE 600 is composed of N codepoints. Each codepoint may include a pair of octets.

[0095] For each codepoint in the MAC-CE 600, there may be one bit (labelled “Ci”, i being a positive integer) which may be used to differentiate whether one or two TCI state ID(s) are associated with the codepoint. If the bit “Ci” is set, the length of the codepoint may be two octets and contain a set of DL TCI states IDs to be activated for multi-TRP operation in the NCR-Fwd DL backhaul link. The remaining 7 bits in the first octet may provide a TCI state ID corresponding to the first TRP; and 7 bits in the second octet may provide a TCI state ID corresponding to the second TRP. If the bit “Ci” is not set, the length of the codepoint is only one octet (i.e. the second octet is not transmitted), and the remaining 7 bits may contain a DL TCI state ID to be activated for single-TRP operation in the NCR-Fwd DL backhaul link.

[0096] By way of example, a first TCI state set (referred to as TCI state set 1) including TCI states with the TCI state IDi,i and the TCI state IDI,2 corresponds to the codepoint 610, ..., and a Nth TCI state set (referred to as TCI state set N) including TCI states with the TCI state IDN.I and the TCI state IDN,2 corresponds to the codepoint 620.

[0097] Following reception of this MAC-CE 600, the network node 140 may transmit a DCI indication to indicate a codepoint to be applied in the NCR-Fwd DL backhaul link for multi-TRP or single-TRP operation. The DCI indication from the network node 140 may indicate a target TCI state set among the N TCI state sets indicated by the MAC-CE 600. For example, if the DCI indication indicates i (i being an integer greater than or equal to 1 and less than or equal to N), the i-th TCI state set indicated by the MAC-CE 600 may be determined as the target TCI state set to be applied for the backhaul procedure. That is, the DCI indicates codepoint “i” from among the (1..N) codepoints that were activated via the MAC-CE.

[0098] Upon reception of the DCI by the NCR-MT 120, the NCR-MT 120 may inform the NCR-Fwd 130 to apply the configuration for the DL backhaul link beams according to the TCI state ID(s) that were activated by the codepoint i of the MAC-CE 600.

[0099] In some example embodiments, the MAC-CE may further include an existence indication such as a presence bit “P” indicating whether the at least one TCI state set comprising one or more TCI states is configured in the MAC-CE. For example, the bit “P” (not shown) may be prefixed to the MAC-CE 600. It is to be understood that remaining bits such as 7 bits of the prefixed octet may contain other information relevant to the operation of the NCR-Fwd backhaul, which will not described here.

[0100] The NCR 110 may obtain the existence indication from the MAC-CE. If the NCR 110 determines, based on the existence indication, that the at least one TCI state set including one or more TCI states is configured in the MAC-CE, the NCR 110 may apply the one or more TCI states for the backhaul procedure in the multiple TRP operation or the single TRP operation. For example, if the bit “P” is set (for example, the bit “P” is equal to 1, the behaviour at the NCR-MT 120 and the NCR-Fwd 130 may be similar to those described with respect to FIG. 6, which will not repeated here.

[0101] In some example embodiments, if the NCR 110 determines, based on the existence indication, that no TCI state is configured in the MAC-CE, the NCR 110 may determine one or more reference TCI states that are currently used by the NCR-MT 120. The NCR 110 may apply the one or more reference TCI states for the backhaul procedure in the multiple TRP operation or the single TRP operation.

[0102] By way of example, if the bit “P” is not set, no TCI state ID is provided in the MAC-CE. Upon reception of the MAC-CE by the NCR-MT 120, the NCR-MT 120 may inform the NCR-Fwd 130 to apply the same TCI state configuration for the DL backhaul link beam(s) as the one which is already activated at the NCR-MT 120. In other words, if NCR-MT 120 is configured with multi-TRP operation, the NCR-Fwd 130 may also use multi-TRP operation following the same TCI configuration as the NCR-MT 120; and if NCR-MT 120 is configured with single-TRP operation, the NCR-Fwd 130 may also use single-TRP operation following the same TCI configuration as the NCR-MT 120.

[0103] Alternatively, or in addition, in some example embodiments where the MAC-CE includes a plurality of codepoints for a plurality of TCI state sets, each codepoint of the MAC-CE may contain either a (single) joint TCI state IDs or (separately) a DL TCI state ID and UL TCI state ID. [0104] By way of example, the DCI may indicate one or two codepoints from among the codepoints activated by MAC-CE. If the DCI indicates two codepoints, the NCR-MT 120 may apply the configuration for multi-TRP operation for the NCR-Fwd backhaul downlink and the NCR-Fwd backhaul uplink according to the corresponding TCI state IDs of the respective codepoints of the MAC-CE. If the DCI indicates one codepoint, the NCR-MT 120 may apply the configuration for single-TRP operation for the NCR-Fwd backhaul downlink and the NCR-Fwd backhaul uplink according to the corresponding TCI state ID(s) of the respective codepoint of the MAC-CE.

[0105] In some example embodiments, the NCR 110 may determine, based on the existence indication in the MAC-CE, a TCI state set is configured in the MAC-CE. If the NCR 110 determines that an indication indicates two TCI states associated with TCI state set are to be for a backhaul uplink and a backhaul downlink between a TRP associated with the network node 140 and the NCR-Fwd 130, the NCR 110 may apply a first beam corresponding to a first TCI state for the backhaul downlink and a second beam corresponding to a second TCI state for the backhaul uplink in the single TRP operation. Otherwise, if the NCR 110 determines that the indication is not set, the NCR 110 may determine a TCI state associated with TCI state set is to be for both backhaul uplink and backhaul downlink between a TRP associated with the network node 140 and the NCR- Fwd 130.

[0106] In some example embodiments, the NCR 110 may determine, based on existence indication such as a presence bit “P” in the MAC-CE, a plurality of TCI state sets is configured in the MAC-CE. The NCR 110 may receive, from the network node 140 via DCI, an indication indicating one or more target TCI state sets to be applied for the backhaul procedure. The indication may be an index or an ID of the target TCI state set in the plurality of TCI sate sets. The NCR 110 may select the one or more target TCI state sets from the plurality of TCI state sets based on the indication.

[0107] In some example embodiments, if the NCR 110 determines that respective further indications related to the one or more target TCI state sets indicates two TCI states associated with each target TCI state set are to be for a backhaul uplink and a backhaul downlink between one or more TRPs associated with the network node 140 and the NCR- Fwd 130, the NCR 110 may apply a first beam corresponding to a first TCI state in a target TCI state set of the one or more target TCI state sets for the backhaul downlink and a second beam corresponding to a second TCI state in the target TCI state set for the backhaul uplink in the single TRP operation.

[0108] If the NCR 110 determines that a further indication related to a target TCI state set is not set, the NCR 110 may determine that a TCI state associated with the target TCI state is to be applied for both backhaul uplink and backhaul downlink between a TRP associated with the network node 140 and the NCR-Fwd 130.

[0109] As used herein, the MAC-CE including TCI states for a backhaul uplink and a backhaul downlink may be referred to as a “unified NCR backhaul link beam activation MAC-CE”. FIG. 7 illustrates an example of a unified NCR backhaul link beam activation MAC-CE 700. The MAC-CE 700 may be applied in combination with a DCI indication. The MAC-CE 700 may be used to activate a set of TCI state IDs for the NCR-Fwd DL backhaul link and the NCR-Fwd UL backhaul link, while the DCI indication is used to indicate which of the activated TCI states IDs may be applied for single-TRP or multi-TRP beam(s).

[0110] The MAC-CE 700 may include an octet 701 (also referred to as Oct 1) containing presence bits and up to eight codepoints containing TCI state IDs. The presence bits, (labelled “Pi”, i being an integer) are used to indicate the presence of a codepoint, where, when Pi is set, the codepoint i (containing TCI State IDi,D and, optionally, TCI State IDi,u) is present in the MAC-CE 700. For example, in the example of FIG. 7, a codepoint 710 (also referred to as codepoint 1), ..., and a codepoint 720 (also referred to as codepoint N, N being an integer greater than 1) are included in the MAC-CE 700.

[OHl] In the first octet of each codepoint, there is one bit (labelled “D/U”) which is used to indicate whether the length of the codepoint is one or two octets. If the D/U bit is set, the length of the codepoint is two octets, where the first and second octet respectively contain a DL TCI state ID and UL TCI state ID to be activated. If the D/U bit is not set, the length of the codepoint is one octet (i.e. the second octet is not transmitted), and the remaining 7 bits of the first octet correspond to a joint TCI state ID, which is applicable for both the DL and UL.

[0112] Taking the codepoint 710 as an example, if the D/U bit in the octet 711 is set, the octet 711 and the octet 712 may respectively contain a DL TCI state ID and UL TCI state ID to be activated. If the D/U set is not set, the octet 711 may correspond to a joint TCI state ID, which is applicable for both the DL and UL, and the octet 712 may be excluded. [0113] In some example embodiments, if one or more presence bits in the MAC-CE are set, following reception of this MAC-CE, the network node 140 may send DCI to indicate one or two codepoints to be applied in the NCR-Fwd DL backhaul link and NCR-Fwd UL backhaul link. The DCI indicates codepoint “i”, and, optionally, a second codepoint “j” from among the (1..8) codepoints that were activated via the MAC-CE.

[0114] Upon reception of the DCI by the NCR-MT 120, the NCR-MT 120 may inform the NCR-Fwd 130 to apply the configuration for the backhaul link beams according to the TCI state ID(s) that were activated by the codepoint(s) of the MAC-CE.

[0115] In some example embodiments, if the NCR 110 determines that the existence indication in the MAC-CE indicates that no TCI state is configured in the MAC-CE, the NCR 110 may determine a reference TCI state that is currently used by the NCR-MT 120 for a control link downlink between a TRP associated with the network node 140 and the NCR-MT 120 and a further reference TCI state that is currently used by the NCR-MT 120 for a control link uplink between a TRP associated with the network node 140 and NCR- MT 120. The NCR 110 may apply a first beam corresponding to the reference TCI state for the backhaul downlink and a second beam corresponding to a further reference TCI state for the backhaul uplink in the multiple TRP operation or the single TRP operation.

[0116] By way of example, if none of the presence bits are set (i.e. no TCI State ID is indicated with the MAC-CE), upon reception of the MAC-CE by the NCR-MT 120, the NCR-MT 120 may inform the NCR-Fwd 130 to apply the same TCI state configuration for the DL and UL backhaul link beam(s) as the ones which are activated at the NCR-MT 120.

[0117] Several example MAC-CEs for the backhaul procedure have been described with respect to FIG. 4 to FIG. 7. It is to be understood that these shown MAC-CE formats are only for the purpose of illustration, without suggesting any limitation. The MAC- CE formats or the bits in these MAC-CE formats can be varied in any suitable ways. These MAC-CEs can be used separately, or in any combination. Scope of the present disclosure is not limited here.

[0118] With one or more of these MAC-CEs, the backhaul link TCI states or backhaul link beams can be indicated for both multiple TRP operation and single TRP operation. That is, both the multiple TRP operation and the single TRP operation can be supported by the forwarding portion at the apparatus such as an NCR-Fwd. By extending the multi - TRP support to the NCR-Fwd backhaul, the backhaul link redundancy in case of signal degradation can be supported. In addition, it can offload traffic from the NCR from one TRP to another in case one TRP becomes congested. With the NCR-backhaul for mutiple-TPR, the transmission reliability and robust can be enhanced.

[0119] FIG. 8 shows a flowchart of an example method 800 implemented at an apparatus such as an NCR 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 110 in FIG. 1.

[0120] At block 810, the NCR 110 receives, at a mobile termination at the NCR 110 such as the NCR-MT 120 from a network node, a MAC-CE associated with beam information for a backhaul procedure between one or more TRPs associated with the network node and a forwarding portion at the NCR 110 such as the NCR-Fwd 130.

[0121] At block 820, the NCR 110 applies, based on the MAC-CE, one or more TCI states of at least one TCI state set indicated in the MAC-CE for the backhaul procedure in a multiple TRP operation or a single TRP operation.

[0122] In some example embodiments, the method 800 may further comprise: in accordance with a determination that a TCI state set comprising two TCI states is obtained from the MAC-CE, determining that the multiple TRP operation is to be used in the backhaul procedure; and applying beams corresponding the two TCI states for backhaul downlink from two TRPs associated with the network node to the forwarding portion at the NCR 110.

[0123] In some example embodiments, the method 800 may further comprise: obtaining, from the MAC-CE, an indication indicating whether the multiple TRP operation is to be used in the backhaul procedure; and in accordance with a determination that the indication indicates that the multiple TRP operation is to be used in the backhaul procedure and a TCI state set comprising two TCI states is obtained from the MAC-CE, applying beams corresponding the two TCI states for backhaul downlink between two TRPs associated with the network node and the forwarding portion at the NCR 110.

[0124] In some example embodiments, the method 800 may further comprise: in accordance with a determination that the indication indicates that the multiple TRP operation is not to be used in the backhaul procedure and a TCI state set comprising a TCI state is obtained from the MAC-CE, determining that the single TRP operation is to be used in the backhaul procedure; and applying a beam corresponding to the TCI state for backhaul downlink between the network node and the forwarding portion at the NCR 110.

[0125] In some example embodiments, the method 800 may further comprise: in accordance with a determination that the indication is changed for indicating that the multiple TRP operation is to be used in the backhaul procedure, switching from the single TRP operation to the multiple TRP operation.

[0126] In some example embodiments, the method 800 may further comprise: obtaining, from the MAC-CE, an indication indicating whether the multiple TRP operation is to be used in the backhaul procedure; and in accordance with a determination that the indication indicates that the multiple TRP operation is to be used in the backhaul procedure and a TCI state set comprising a TCI state is obtained from the MAC-CE, determining a reference TCI state that is currently used by the mobile termination at the NCR 110; and applying a first beam corresponding the TCI state and a second beam corresponding to the reference TCI state for backhaul downlink between two TRPs associated with the network node and the forwarding portion at the NCR 110.

[0127] In some example embodiments, the method 800 further comprises: receiving, from the network node via a downlink control information, DCI, an indication indicating a target TCI state set to be applied for the backhaul procedure; selecting the target TCI state set from the plurality of TCI state sets based on the indication; in accordance with a determination that a further indication related to the target TCI state set indicates that two TCI states are associated with the target TCI state set, determining that the multiple TRP operation is to be used in the backhaul procedure; and applying beams corresponding the two TCI states for backhaul downlink between two TRPs associated with the network node and the forwarding portion at the NCR 110.

[0128] In some example embodiments, the method 800 further comprises: in accordance with a determination that the further indication associated with the target TCI state set indicates that a TCI state is associated with the target TCI state set, determining that the single TRP operation is to be used in the backhaul procedure; and applying a beam corresponding to the TCI state for backhaul downlink between the network node and the forwarding portion at the NCR 110.

[0129] In some example embodiments, the method 800 further comprises: obtaining, from the MAC-CE, an existence indication indicating whether the at least one TCI state set comprising one or more TCI states is configured in the MAC-CE; and in accordance with a determination, based on the existence indication, that the at least one TCI state set comprising one or more TCI states is configured in the MAC-CE, applying the one or more TCI states for the backhaul procedure in the multiple TRP operation or the single TRP operation.

[0130] In some example embodiments, the method 800 further comprises: in accordance with a determination, determining on the existence indication, that no TCI state is configured in the MAC-CE, determine one or more reference TCI states that are currently used by the mobile termination at the NCR 110; and applying the one or more reference TCI states for the backhaul procedure in the multiple TRP operation or the single TRP operation.

[0131] In some example embodiments, the method 800 further comprises: determining, based on existence indication in the MAC-CE, a TCI state set is configured in the MAC- CE; and in accordance with a determination that an indication indicates two TCI states associated with TCI state set are to be for a backhaul uplink and a backhaul downlink between a TRP associated with the network node and the forwarding portion at the NCR 110, applying a first beam corresponding to a first TCI state for the backhaul downlink and a second beam corresponding to a second TCI state for the backhaul uplink in the single TRP operation.

[0132] In some example embodiments, the method 800 further comprises: in accordance with a determination that indication is not set, determining a TCI state associated with TCI state set is to be for both backhaul uplink and backhaul downlink between a TRP associated with the network node and the forwarding portion at the NCR 110.

[0133] In some example embodiments, the method 800 further comprises: determining, based on existence indication in the MAC-CE, a plurality of TCI state sets is configured in the MAC-CE; receiving, from the network node via a downlink control information, DCI, an indication indicating one or more target TCI state sets to be applied for the backhaul procedure; selecting the one or more target TCI state sets from the plurality of TCI state sets based on the indication; and in accordance with a determination that respective further indications related to the one or more target TCI state sets indicates two TCI states associated with each target TCI state set are to be for a backhaul uplink and a backhaul downlink between one or more TRPs associated with the network node and the forwarding portion at the NCR 110, applying a first beam corresponding to a first TCI state in a target TCI state set of the one or more target TCI state sets for the backhaul downlink and a second beam corresponding to a second TCI state in the target TCI state set for the backhaul uplink in the single TRP operation.

[0134] In some example embodiments, the method 800 may further comprise: in accordance with a determination that a further indication related to a target TCI state set is not set, determining that a TCI state associated with the target TCI state is to be applied for both backhaul uplink and backhaul downlink between a TRP associated with the network node and the forwarding portion at the NCR 110.

[0135] In some example embodiments, each TCI state set in the plurality of TCI state sets is corresponding to a codepoint, and wherein the target TCI state set to be applied for the backhaul procedure is indicated in the DCI by a target codepoint corresponding to the target TCI state set.

[0136] In some example embodiments, the method 800 may further comprise: in accordance with a determination that existence indication in the MAC-CE indicates that no TCI state is configured in the MAC-CE, determining a reference TCI state that is currently used by the mobile termination at the NCR 110 for a control link downlink between a TRP associated with the network node and the mobile termination at the NCR 110 and a further reference TCI state that is currently used by the mobile termination at the NCR 110 for a control link uplink between a TRP associated with the network node and the mobile termination at the NCR 110; and applying a first beam corresponding to the reference TCI state for the backhaul downlink and a second beam corresponding to a further reference TCI state for the backhaul uplink in the multiple TRP operation or the single TRP operation.

[0137] FIG. 9 shows a flowchart of an example method 900 implemented at an apparatus such as a network node in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the method 900 will be described from the perspective of the network node 140 in FIG. 1.

[0138] At block 910, the network node 140 transmits, to an NCR, a MAC-CE associated with beam information for a backhaul procedure between one or more TRPs associated with the network node 140 and a forwarding portion at the NCR. The MAC-CE comprises at least one TCI state set comprising one or more TCI states for the backhaul procedure in a multiple TRP operation or a single TRP operation and/or an existence indication indicates whether the MAC-CE is configured with at least one TCI state.

[0139] In some example embodiments, the MAC-CE comprises an indication indicating whether more than one TCI states is associated with a TCI state set.

[0140] In some example embodiments, the MAC-CE comprises a further indication indicating TCI states associated with TCI state set are to be for a backhaul uplink and a backhaul downlink between a TRP associated with the network node 140 and the forwarding portion at the NCR.

[0141] In some example embodiments, the plurality of TCI state sets is indicated in the MAC-CE for the backhaul procedure, and the method 900 further comprises: transmitting, to the NCR via a DCI, an indication indicating one or more target TCI state sets from the plurality of TCI state sets are to be applied for the backhaul procedure.

[0142] In some example embodiments, each TCI state set in the plurality of TCI state sets is corresponding to a codepoint, and wherein the target TCI state set to be applied for the backhaul procedure is indicated in the DCI by a target codepoint corresponding to the target TCI state set.

[0143] In some example embodiments, a first apparatus capable of performing any of the method 800 (for example, the NCR 110 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 first apparatus may be implemented as or included in the NCR 110 in FIG. 1.

[0144] In some example embodiments, the first apparatus comprises means for receiving, at a mobile termination at an apparatus from a network node, a medium access controlcontrol element, MAC-CE, associated with beam information for a backhaul procedure between one or more transmit/receive points, TRPs, associated with the network node and a forwarding portion at the apparatus; means for applying, based on the MAC-CE, one or more transmission configuration indicator, TCI, states of at least one TCI state set indicated in the MAC-CE for the backhaul procedure in a multiple TRP operation or a single TRP operation. [0145] In some example embodiments, the first apparatus may further comprise means for in accordance with a determination that a TCI state set comprising two TCI states is obtained from the MAC-CE, determining that the multiple TRP operation is to be used in the backhaul procedure; and means for applying beams corresponding the two TCI states for backhaul downlink from two TRPs associated with the network node to the forwarding portion at the apparatus.

[0146] In some example embodiments, the first apparatus may further comprise means for obtaining, from the MAC-CE, an indication indicating whether the multiple TRP operation is to be used in the backhaul procedure; and in accordance with a determination that the indication indicates that the multiple TRP operation is to be used in the backhaul procedure and a TCI state set comprising two TCI states is obtained from the MAC-CE, means for applying beams corresponding the two TCI states for backhaul downlink between two TRPs associated with the network node and the forwarding portion at the apparatus.

[0147] In some example embodiments, the first apparatus may further comprise means for in accordance with a determination that the indication indicates that the multiple TRP operation is not to be used in the backhaul procedure and a TCI state set comprising a TCI state is obtained from the MAC-CE, determining that the single TRP operation is to be used in the backhaul procedure; and means for applying a beam corresponding to the TCI state for backhaul downlink between the network node and the forwarding portion at the apparatus.

[0148] In some example embodiments, the first apparatus may further comprise in accordance with a determination that the indication is changed for indicating that the multiple TRP operation is to be used in the backhaul procedure, switching from the single TRP operation to the multiple TRP operation.

[0149] In some example embodiments, the first apparatus may further comprise means for obtaining, from the MAC-CE, an indication indicating whether the multiple TRP operation is to be used in the backhaul procedure; and in accordance with a determination that the indication indicates that the multiple TRP operation is to be used in the backhaul procedure and a TCI state set comprising a TCI state is obtained from the MAC-CE, means for determining a reference TCI state that is currently used by the mobile termination at the apparatus; and means for applying a first beam corresponding the TCI state and a second beam corresponding to the reference TCI state for backhaul downlink between two TRPs associated with the network node and the forwarding portion at the apparatus.

[0150] In some example embodiments, the first apparatus further comprises: means for receiving, from the network node via a downlink control information, DCI, an indication indicating a target TCI state set to be applied for the backhaul procedure; means for selecting the target TCI state set from the plurality of TCI state sets based on the indication; in accordance with a determination that a further indication related to the target TCI state set indicates that two TCI states are associated with the target TCI state set, means for determining that the multiple TRP operation is to be used in the backhaul procedure; and means for applying beams corresponding the two TCI states for backhaul downlink between two TRPs associated with the network node and the forwarding portion at the apparatus.

[0151] In some example embodiments, the first apparatus further comprises: in accordance with a determination that the further indication associated with the target TCI state set indicates that a TCI state is associated with the target TCI state set, means for determining that the single TRP operation is to be used in the backhaul procedure; and means for applying a beam corresponding to the TCI state for backhaul downlink between the network node and the forwarding portion at the apparatus.

[0152] In some example embodiments, the first apparatus further comprises: means for obtaining, from the MAC-CE, an existence indication indicating whether the at least one TCI state set comprising one or more TCI states is configured in the MAC-CE; and in accordance with a determination, means for applying on the existence indication, that the at least one TCI state set comprising one or more TCI states is configured in the MAC- CE, apply the one or more TCI states for the backhaul procedure in the multiple TRP operation or the single TRP operation.

[0153] In some example embodiments, the first apparatus further comprises: in accordance with a determination, means for determining on the existence indication, that no TCI state is configured in the MAC-CE, determine one or more reference TCI states that are currently used by the mobile termination at the apparatus; and means for applying the one or more reference TCI states for the backhaul procedure in the multiple TRP operation or the single TRP operation.

[0154] In some example embodiments, the first apparatus further comprises: means for determining, based on existence indication in the MAC-CE, a TCI state set is configured in the MAC-CE; and in accordance with a determination that an indication indicates two TCI states associated with TCI state set are to be for a backhaul uplink and a backhaul downlink between a TRP associated with the network node and the forwarding portion at the apparatus, means for applying a first beam corresponding to a first TCI state for the backhaul downlink and a second beam corresponding to a second TCI state for the backhaul uplink in the single TRP operation.

[0155] In some example embodiments, the first apparatus further comprises: in accordance with a determination that indication is not set, means for determining a TCI state associated with TCI state set is to be for both backhaul uplink and backhaul downlink between a TRP associated with the network node and the forwarding portion at the apparatus.

[0156] In some example embodiments, the first apparatus further comprises: means for determining, based on existence indication in the MAC-CE, a plurality of TCI state sets is configured in the MAC-CE; means for receiving, from the network node via a downlink control information, DCI, an indication indicating one or more target TCI state sets to be applied for the backhaul procedure; means for selecting the one or more target TCI state sets from the plurality of TCI state sets based on the indication; and in accordance with a determination that respective further indications related to the one or more target TCI state sets indicates two TCI states associated with each target TCI state set are to be for a backhaul uplink and a backhaul downlink between one or more TRPs associated with the network node and the forwarding portion at the apparatus, means for applying a first beam corresponding to a first TCI state in a target TCI state set of the one or more target TCI state sets for the backhaul downlink and a second beam corresponding to a second TCI state in the target TCI state set for the backhaul uplink in the single TRP operation.

[0157] In some example embodiments, the first apparatus may further comprise means for in accordance with a determination that a further indication related to a target TCI state set is not set, determining that a TCI state associated with the target TCI state is to be applied for both backhaul uplink and backhaul downlink between a TRP associated with the network node and the forwarding portion at the apparatus.

[0158] In some example embodiments, each TCI state set in the plurality of TCI state sets is corresponding to a codepoint, and wherein the target TCI state set to be applied for the backhaul procedure is indicated in the DCI by a target codepoint corresponding to the target TCI state set.

[0159] In some example embodiments, the first apparatus further comprises: in accordance with a determination that existence indication in the MAC-CE indicates that no TCI state is configured in the MAC-CE, means for determining a reference TCI state that is currently used by the mobile termination at the apparatus for a control link downlink between a TRP associated with the network node and the mobile termination at the apparatus and a further reference TCI state that is currently used by the mobile termination at the apparatus for a control link uplink between a TRP associated with the network node and the mobile termination at the apparatus; and means for applying a first beam corresponding to the reference TCI state for the backhaul downlink and a second beam corresponding to a further reference TCI state for the backhaul uplink in the multiple TRP operation or the single TRP operation.

[0160] In some example embodiments, the apparatus comprises a network-controlled repeater, NCR, the mobile termination at the apparatus comprises an NCR-mobile termination, NCR-MT, and the forwarding portion at the apparatus comprises an NCR- forwarding, NCR-Fwd.

[0161] In some example embodiments, a second apparatus capable of performing any of the method 900 (for example, the network node 140 in FIG. 1) may comprise means for performing the respective operations of the method 900. 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 network node 140 in FIG. 1.

[0162] In some example embodiments, the second apparatus comprises means for transmitting, to a network-controlled repeater, NCR, a medium access control -control element, MAC-CE, associated with beam information for a backhaul procedure between one or more transmit/receive points, TRPs, associated with an apparatus and a forwarding portion at the NCR, wherein the MAC-CE comprises at least one transmission configuration indicator, TCI, state set comprising one or more TCI states for the backhaul procedure in a multiple TRP operation or a single TRP operation and/or an existence indication indicates whether the MAC-CE is configured with at least one TCI state.

[0163] In some example embodiments, the MAC-CE comprises an indication indicating whether more than one TCI states is associated with a TCI state set.

[0164] In some example embodiments, the MAC-CE comprises a further indication indicating TCI states associated with TCI state set are to be for a backhaul uplink and a backhaul downlink between a TRP associated with the apparatus and the forwarding portion at the NCR.

[0165] In some example embodiments, the plurality of TCI state sets is indicated in the MAC-CE for the backhaul procedure, and wherein the apparatus is caused to: means for transmitting, to the NCR via a DCI, an indication indicating one or more target TCI state sets from the plurality of TCI state sets are to be applied for the backhaul procedure.

[0166] In some example embodiments, each TCI state set in the plurality of TCI state sets is corresponding to a codepoint, and wherein the target TCI state set to be applied for the backhaul procedure is indicated in the DCI by a target codepoint corresponding to the target TCI state set.

[0167] In some example embodiments, the apparatus comprises a network node and the forwarding portion at the NCR comprises an NCR-Fwd.

[0168] FIG. 10 is a simplified block diagram of a device 1000 that is suitable for implementing example embodiments of the present disclosure. The device 1000 may be provided to implement a communication device, for example, the NCR 110, the terminal device 150 or the network node 140 as shown in FIG. 1. As shown, the device 1000 includes one or more processors 1010, one or more memories 1020 coupled to the processor 1010, and one or more communication modules 1040 coupled to the processor 1010.

[0169] The communication module 1040 is for bidirectional communications. The communication module 1040 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 1040 may include at least one antenna.

[0170] The processor 1010 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 1000 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.

[0171] The memory 1020 may include one or more non-volatile memories and one or more volatile memories. Examples of the non-volatile memories include, but are not limited to, a Read Only Memory (ROM) 1024, 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) 1022 and other volatile memories that will not last in the power-down duration.

[0172] A computer program 1030 includes computer executable instructions that are executed by the associated processor 1010. The instructions of the program 1030 may include instructions for performing operations/acts of some example embodiments of the present disclosure. The program 1030 may be stored in the memory, e.g., the ROM 1024. The processor 1010 may perform any suitable actions and processing by loading the program 1030 into the RAM 1022.

[0173] The example embodiments of the present disclosure may be implemented by means of the program 1030 so that the device 1000 may perform any process of the disclosure as discussed with reference to FIG. 3 to FIG. 9. The example embodiments of the present disclosure may also be implemented by hardware or by a combination of software and hardware.

[0174] In some example embodiments, the program 1030 may be tangibly contained in a computer readable medium which may be included in the device 1000 (such as in the memory 1020) or other storage devices that are accessible by the device 1000. The device 1000 may load the program 1030 from the computer readable medium to the RAM 1022 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).

[0175] FIG. 11 shows an example of the computer readable medium 1100 which may be in form of CD, DVD or other optical storage disk. The computer readable medium 1100 has the program 1030 stored thereon.

[0176] Generally, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects 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.

[0177] 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.

[0178] 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. [0179] 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.

[0180] 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.

[0181] 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. Likewise, 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.

[0182] 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: receive, at a mobile termination at the apparatus from a network node, a medium access control -control element, MAC-CE, associated with beam information for a backhaul procedure between one or more transmit/receive points, TRPs, associated with the network node and a forwarding portion at the apparatus; apply, based on the MAC-CE, one or more transmission configuration indicator, TCI, states of at least one TCI state set indicated in the MAC-CE for the backhaul procedure in a multiple TRP operation or a single TRP operation.

2. The apparatus of claim 1, wherein the apparatus is caused to: in accordance with a determination that a TCI state set comprising two TCI states is obtained from the MAC-CE, determine that the multiple TRP operation is to be used in the backhaul procedure; and apply beams corresponding the two TCI states for backhaul downlink from two TRPs associated with the network node to the forwarding portion at the apparatus.

3. The apparatus of claim 1, wherein the apparatus is caused to: obtain, from the MAC CE, an indication indicating whether the multiple TRP operation is to be used in the backhaul procedure; and in accordance with a determination that the indication indicates that the multiple TRP operation is to be used in the backhaul procedure and a TCI state set comprising two TCI states is obtained from the MAC-CE, apply beams corresponding the two TCI states for backhaul downlink between two TRPs associated with the network node and the forwarding portion at the apparatus.

4. The apparatus of claim 3, wherein the apparatus is caused to: in accordance with a determination that the indication indicates that the multiple TRP operation is not to be used in the backhaul procedure and a TCI state set comprising a TCI state is obtained from the MAC-CE, determine that the single TRP operation is to be used in the backhaul procedure; and apply a beam corresponding to the TCI state for backhaul downlink between the network node and the forwarding portion at the apparatus.

5. The apparatus of claim 4, wherein the apparatus is caused to: in accordance with a determination that the indication is changed for indicating that the multiple TRP operation is to be used in the backhaul procedure, switch from the single TRP operation to the multiple TRP operation.

6. The apparatus of claim 1, wherein the apparatus is caused to: obtain, from the MAC CE, an indication indicating whether the multiple TRP operation is to be used in the backhaul procedure; and in accordance with a determination that the indication indicates that the multiple TRP operation is to be used in the backhaul procedure and a TCI state set comprising a TCI state is obtained from the MAC-CE, determine a reference TCI state that is currently used by the mobile termination at the apparatus; and apply a first beam corresponding the TCI state and a second beam corresponding to the reference TCI state for backhaul downlink between two TRPs associated with the network node and the forwarding portion at the apparatus.

7. The apparatus of claim 1, wherein a plurality of TCI state sets is indicated in the MAC-CE for the backhaul procedure, and wherein the first apparatus is caused to: receive, from the network node via a downlink control information, DCI, an indication indicating a target TCI state set to be applied for the backhaul procedure; select the target TCI state set from the plurality of TCI state sets based on the indication; in accordance with a determination that a further indication related to the target TCI state set indicates that two TCI states are associated with the target TCI state set, determine that the multiple TRP operation is to be used in the backhaul procedure; and apply beams corresponding the two TCI states for backhaul downlink between two TRPs associated with the network node and the forwarding portion at the apparatus.

8. The apparatus of claim 7, wherein the first apparatus is caused to: in accordance with a determination that the further indication associated with the target TCI state set indicates that a TCI state is associated with the target TCI state set, determine that the single TRP operation is to be used in the backhaul procedure; and apply a beam corresponding to the TCI state for backhaul downlink between the network node and the forwarding portion at the apparatus.

9. The apparatus of any of claims 3-8, wherein the first apparatus is caused to: obtain, from the MAC-CE, an existence indication indicating whether the at least one TCI state set comprising one or more TCI states is configured in the MAC-CE; and in accordance with a determination, based on the existence indication, that the at least one TCI state set comprising one or more TCI states is configured in the MAC-CE, apply the one or more TCI states for the backhaul procedure in the multiple TRP operation or the single TRP operation.

10. The apparatus of claim 9, wherein the first apparatus is caused to: in accordance with a determination, based on the existence indication, that no TCI state is configured in the MAC-CE, determine one or more reference TCI states that are currently used by the mobile termination at the apparatus; and apply the one or more reference TCI states for the backhaul procedure in the multiple TRP operation or the single TRP operation.

11. The apparatus of claim 1, wherein the first apparatus is caused to: determine, based on existence indication in the MAC-CE, a TCI state set is configured in the MAC-CE; and in accordance with a determination that an indication indicates two TCI states associated with TCI state set are to be for a backhaul uplink and a backhaul downlink between a TRP associated with the network node and the forwarding portion at the apparatus, apply a first beam corresponding to a first TCI state for the backhaul downlink and a second beam corresponding to a second TCI state for the backhaul uplink in the single TRP operation.

12. The apparatus of claim 11, wherein the first apparatus is caused to: in accordance with a determination that indication is not set, determine a TCI state associated with TCI state set is to be for both backhaul uplink and backhaul downlink between a TRP associated with the network node and the forwarding portion at the apparatus.

13. The apparatus of claim 1, wherein the first apparatus is caused to: determine, based on existence indication in the MAC-CE, a plurality of TCI state sets is configured in the MAC-CE; receive, from the network node via a downlink control information, DCI, an indication indicating one or more target TCI state sets to be applied for the backhaul procedure; select the one or more target TCI state sets from the plurality of TCI state sets based on the indication; and in accordance with a determination that respective further indications related to the one or more target TCI state sets indicates two TCI states associated with each target TCI state set are to be for a backhaul uplink and a backhaul downlink between one or more TRPs associated with the network node and the forwarding portion at the apparatus, apply a first beam corresponding to a first TCI state in a target TCI state set of the one or more target TCI state sets for the backhaul downlink and a second beam corresponding to a second TCI state in the target TCI state set for the backhaul uplink in the single TRP operation.

14. The apparatus of claim 13, wherein the apparatus is caused to: in accordance with a determination that a further indication related to a target TCI state set is not set, determine that a TCI state associated with the target TCI state is to be applied for both backhaul uplink and backhaul downlink between a TRP associated with the network node and the forwarding portion at the apparatus.

15. The apparatus of any of claims 7, 8, 13 or 14, wherein each TCI state set in the plurality of TCI state sets is corresponding to a codepoint, and wherein the target TCI state set to be applied for the backhaul procedure is indicated in the DCI by a target codepoint corresponding to the target TCI state set.

16. The apparatus of claim 14, wherein the first apparatus is caused to: in accordance with a determination that existence indication in the MAC-CE indicates that no TCI state is configured in the MAC-CE, determine a reference TCI state that is currently used by the mobile termination at the apparatus for a control link downlink between a TRP associated with the network node and the mobile termination at the apparatus and a further reference TCI state that is currently used by the mobile termination at the apparatus for a control link uplink between a TRP associated with the network node and the mobile termination at the apparatus; and apply a first beam corresponding to the reference TCI state for the backhaul downlink and a second beam corresponding to a further reference TCI state for the backhaul uplink in the multiple TRP operation or the single TRP operation.

17. The apparatus of any of claims 1-16, wherein the apparatus comprises a network- controlled repeater, NCR, the mobile termination at the apparatus comprises an NCR-mobile termination, NCR-MT, and the forwarding portion at the apparatus comprises an NCR- forwarding, NCR-Fwd.

18. 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: transmit, to a network-controlled repeater, NCR, a medium access control -control element, MAC-CE, associated with beam information for a backhaul procedure between one or more transmit/receive points, TRPs, associated with the apparatus and a forwarding portion at the NCR, wherein the MAC-CE comprises at least one transmission configuration indicator, TCI, state set comprising one or more TCI states for the backhaul procedure in a multiple TRP operation or a single TRP operation and/or an existence indication indicates whether the MAC- CE is configured with at least one TCI state.

19. The apparatus of claim 18, wherein the MAC-CE comprises an indication indicating whether more than one TCI states is associated with a TCI state set.

20. The apparatus of claim 18, wherein the MAC-CE comprises a further indication indicating TCI states associated with TCI state set are to be for a backhaul uplink and a backhaul downlink between a TRP associated with the apparatus and the forwarding portion at the NCR.

21. The apparatus of any of claims 18-20, wherein the plurality of TCI state sets is indicated in the MAC-CE for the backhaul procedure, and wherein the apparatus is caused to: transmit, to the NCR via a DCI, an indication indicating one or more target TCI state sets from the plurality of TCI state sets are to be applied for the backhaul procedure.

22. The apparatus of claim 21, wherein each TCI state set in the plurality of TCI state sets is corresponding to a codepoint, and wherein the target TCI state set to be applied for the backhaul procedure is indicated in the DCI by a target codepoint corresponding to the target TCI state set.

23. The apparatus of any of claims 18-22, wherein the apparatus comprises a network node and the forwarding portion at the NCR comprises an NCR-Fwd.

24. A method comprising: receiving, at a mobile termination at an apparatus from a network node, a medium access control -control element, MAC-CE, associated with beam information for a backhaul procedure between one or more transmit/receive points, TRPs, associated with the network node and a forwarding portion at the apparatus; and applying, based on the MAC-CE, one or more transmission configuration indicator, TCI, states of at least one TCI state set indicated in the MAC-CE for the backhaul procedure in a multiple TRP operation or a single TRP operation.

25. A method comprising: transmitting, at an apparatus to a network-controlled repeater, NCR, a medium access control -control element, MAC-CE, associated with beam information for a backhaul procedure between one or more transmit/receive points, TRPs, associated with the apparatus and a forwarding portion at the NCR, wherein the MAC-CE comprises at least one transmission configuration indicator, TCI, state set comprising one or more TCI states for the backhaul procedure in a multiple TRP operation or a single TRP operation and/or an existence indication indicates whether the MAC-CE is configured with at least one TCI state.

26. A first apparatus comprising: means for receiving, at a mobile termination at the apparatus from a network node, a medium access control -control element, MAC-CE, associated with beam information for a backhaul procedure between one or more transmit/receive points, TRPs, associated with the network node and a forwarding portion at the apparatus; and means for applying, based on the MAC-CE, one or more transmission configuration indicator, TCI, states of at least one TCI state set indicated in the MAC-CE for the backhaul procedure in a multiple TRP operation or a single TRP operation.

27. A second apparatus comprising: means for transmitting, to a network-controlled repeater, NCR, a medium access control -control element, MAC-CE, associated with beam information for a backhaul procedure between one or more transmit/receive points, TRPs, associated with the apparatus and a forwarding portion at the NCR, wherein the MAC-CE comprises at least one transmission configuration indicator, TCI, state set comprising one or more TCI states for the backhaul procedure in a multiple TRP operation or a single TRP operation and/or an existence indication indicates whether the MAC-CE is configured with at least one TCI state.

28. A computer readable medium comprising instructions stored thereon for causing an apparatus at least to perform the method of claim 24 or the method of claim 25.