Method and apparatus for a smart repeater

Abstract

A method is disclosed that includes receiving, by a repeater, access link information from an access point over a backhaul link, where the access link information includes received power of one or more reference signals or an indication of a spatial filter for the access link, and obtaining, by the repeater, at least one spatial filter pair for the backhaul link and the access link based at least in part on the access link information.

Description

[Technical Field]

[0001] The following exemplary embodiments relate to wireless communications. [Background technology]

[0002] In wireless networks, the transmission and reception of wireless signals may be performed via directional spatial filters (beams) to improve signal quality, reduce interference across neighboring nodes, and compensate for additional propagation path loss due to the use of higher carrier frequencies. A challenge exists as to how to obtain optimal spatial filters (beams) for repeaters that may be used to amplify and forward signals between terminal devices and access points of the wireless communication network. Summary of the Invention

[0003] The scope of protection sought for various exemplary embodiments is set forth in the claims. The exemplary embodiments and features described herein that do not fall within the scope of the claims, if any, should be construed as examples useful in understanding the various exemplary embodiments.

[0004] 1. An apparatus comprising: at least one processor; and at least one transceiver; wherein the at least one transceiver is configured to receive access link information from an access point via a backhaul link, the access link information including received power of one or more reference signals or an indication of a spatial filter for the access link; and wherein the at least one processor is configured to obtain at least one spatial filter pair for the backhaul link and the access link based at least in part on the access link information.

[0005] According to one aspect, an apparatus is provided, comprising: at least one processor; and at least one memory containing computer program code, wherein the at least one memory and the computer program code, together with the at least one processor, are configured to cause the apparatus to: receive access link information from an access point via a backhaul link, the access link information including received power of one or more reference signals or an indication of a spatial filter for the access link; and obtain at least one spatial filter pair for the backhaul link and the access link based at least in part on the access link information.

[0006] According to another aspect, provided is an apparatus comprising means for receiving access link information from an access point via a backhaul link, the access link information including received power of one or more reference signals or an indication of a spatial filter for the access link; and obtaining at least one spatial filter pair for the backhaul link and the access link based at least in part on the access link information.

[0007] According to another aspect, a method is provided that includes receiving, by a repeater, access link information from an access point over a backhaul link, the access link information including received power of one or more reference signals or an indication of a spatial filter for the access link; and obtaining, by the repeater, at least one spatial filter pair for the backhaul link and the access link based at least in part on the access link information.

[0008] According to another aspect, provided is a computer program product including program instructions that, when executed on a computing device, cause the computing device to at least receive access link information from an access point over a backhaul link, the access link information including received power of one or more reference signals or an indication of a spatial filter for the access link; and obtain at least one spatial filter pair for the backhaul link and the access link based at least in part on the access link information.

[0009] According to another aspect, provided is a computer program product comprising instructions for causing an apparatus to at least receive access link information from an access point via a backhaul link, the access link information including received power of one or more reference signals or an indication of a spatial filter for the access link, and obtain at least one spatial filter pair for the backhaul link and the access link based at least in part on the access link information.

[0010] According to another aspect, a computer-readable medium is provided that includes program instructions to cause an apparatus to at least receive access link information from an access point via a backhaul link, the access link information including received power of one or more reference signals or an indication of a spatial filter for the access link, and obtain at least one spatial filter pair for the backhaul link and the access link based at least in part on the access link information.

[0011] According to another aspect, provided is a non-transitory computer-readable medium comprising program instructions to cause an apparatus to at least receive access link information from an access point via a backhaul link, the access link information including received power of one or more reference signals or an indication of a spatial filter for the access link, and obtain at least one spatial filter pair for the backhaul link and the access link based at least in part on the access link information.

[0012] 1. An apparatus comprising: at least one processor; and at least one transceiver; wherein the at least one processor is configured to obtain access link information for a repeater, the access link information including received power of one or more reference signals or an indication of a spatial filter for the access link; and wherein the at least one transceiver is configured to transmit the access link information to the repeater via a backhaul link.

[0013] According to another aspect, an apparatus is provided, comprising: at least one processor; and at least one memory containing computer program code, wherein the at least one memory and the computer program code, together with the at least one processor, are configured to cause the apparatus to obtain access link information for a repeater, the access link information including received power of one or more reference signals or an indication of a spatial filter for the access link; and transmit the access link information to the repeater via a backhaul link.

[0014] According to another aspect, provided is an apparatus comprising means for obtaining access link information of a repeater, the access link information including received power of one or more reference signals or an indication of a spatial filter for the access link, and transmitting the access link information to the repeater via a backhaul link.

[0015] According to another aspect, a method is provided that includes obtaining, by an access point, access link information for a repeater, the access link information including received power of one or more reference signals or an indication of a spatial filter for the access link; and transmitting, by the access point, the access link information to the repeater via a backhaul link.

[0016] According to another aspect, a computer program product is provided that includes instructions to cause an apparatus to at least obtain access link information of a repeater, where the access link information includes received power of one or more reference signals or an indication of a spatial filter for the access link, and transmit the access link information to the repeater via a backhaul link.

[0017] According to another aspect, a computer program product is provided that includes program instructions that, when executed on a computing device, cause the computing device to at least obtain access link information of a repeater, the access link information including received power of one or more reference signals or an indication of a spatial filter for the access link, and transmit the access link information to the repeater via a backhaul link.

[0018] According to another aspect, a computer-readable medium is provided that includes program instructions to cause an apparatus to at least obtain access link information of a repeater, the access link information including received power of one or more reference signals or an indication of a spatial filter for the access link, and transmit the access link information to the repeater via a backhaul link.

[0019] According to another aspect, a non-transitory computer-readable medium is provided that includes program instructions to cause an apparatus to at least obtain access link information of a repeater, where the access link information includes received power of one or more reference signals or an indication of a spatial filter for the access link, and transmit the access link information to the repeater via a backhaul link.

[0020] According to another aspect, a system is provided comprising at least a repeater and an access point of a wireless communication network. The access point is configured to obtain access link information for the repeater, the access link information including received power of one or more reference signals or an indication of a spatial filter for the access link, and to transmit the access link information to the repeater via a backhaul link. The repeater is configured to receive the access link information from the access point via the backhaul link and to obtain at least one spatial filter pair for the backhaul link and the access link based at least in part on the access link information.

[0021] According to another aspect, a system is provided comprising at least a repeater and an access point of a wireless communications network. The access point comprises means for obtaining access link information for the repeater, the access link information including received power of one or more reference signals or an indication of a spatial filter for the access link, and transmitting the access link information to the repeater via a backhaul link. The repeater comprises means for receiving the access link information from the access point via the backhaul link and for obtaining at least one spatial filter pair for the backhaul link and the access link based at least in part on the access link information.

[0022] Various exemplary embodiments are described in more detail below with reference to the accompanying drawings. [Brief explanation of the drawings]

[0023] [Figure 1] 1 illustrates an exemplary embodiment of a cellular communication network. [Figure 2] FIG. 1 is a high-level schematic diagram of a smart repeater architecture. [Figure 3] FIG. 1 illustrates a beam refinement procedure. [Figure 4] FIG. 10 is a diagram illustrating an example of initial beam pair establishment. [Figure 5] FIG. 1 illustrates an example of access point beam refinement. [Figure 6] FIG. 1 illustrates an example of smart repeater backhaul beam improvement. [Figure 7] A figure showing an example of smart repeater access beam selection. [Figure 8] FIG. 1 illustrates a simultaneous beam refinement procedure for a single reference signal set, according to an exemplary embodiment. [Figure 9] FIG. 1 shows a signaling diagram according to some exemplary embodiments. [Figure 10] FIG. 1 shows a signaling diagram according to some exemplary embodiments. [Figure 11] 1 is a flowchart according to some example embodiments. [Figure 12] 1 is a flowchart according to some example embodiments. [Figure 13] 1 illustrates an apparatus according to several exemplary embodiments. [Figure 14] 1 illustrates an apparatus according to several exemplary embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0024] The following embodiments are illustrative. Although this specification may refer to "an," "one," or "some" embodiments in several places throughout the text, this does not necessarily mean that each reference is to the same embodiment or that a particular feature applies only to a single embodiment. Single features of different embodiments may be combined to provide other embodiments.

[0025] In the following, several different exemplary embodiments are described using radio access architectures based on Long Term Evolution Advanced (LTE Advanced, LTE-A), New Radio (NR, 5G), or Beyond 5G as examples of access architectures to which the exemplary embodiments may be applied, without constraining the exemplary embodiments to such architectures.

[0026] However, it will be apparent to those skilled in the art that the exemplary embodiments may also be applied to other types of communication networks having suitable means by appropriately adjusting the parameters and procedures. Some examples of other options for a suitable system may be a Universal Mobile Telecommunications System (UMTS) Radio Access Network (UTRAN or E-UTRAN), Long Term Evolution (LTE, substantially the same as E-UTRA), a Wireless Local Area Network (WLAN or Wi-Fi), Worldwide Interoperable Microwave Access (WiMAX), Bluetooth, Personal Communications Services (PCS), ZigBee, Wideband Code Division Multiple Access (WCDMA), a system using Ultra Wideband (UWB) technology, a sensor network, a Mobile Ad Hoc Network (MANET), and an Internet Protocol Multimedia Subsystem (IMS), or a combination thereof.

[0027] 1 shows an example of a simplified system architecture showing several elements and functional entities, all of which are logical units, the implementation of which may differ from those shown. The connections shown in FIG. 1 are logical connections, and the actual physical connections may differ. It will be apparent to one skilled in the art that the system may include functions and structures other than those shown in FIG. 1.

[0028] However, the exemplary embodiment is not limited to the system given as an example, and those skilled in the art can apply this solution to other communication systems given the required characteristics.

[0029] The example of FIG. 1 shows a portion of an exemplary radio access network.

[0030] 1 shows user devices 100 and 102 configured to be wirelessly connected over one or more communication channels in a cell served by an access node (e.g., (e / g)NodeB) 104. The physical link from the user devices to the (e / g)NodeB may be referred to as an uplink or reverse link, and the physical link from the (e / g)NodeB to the user devices may be referred to as a downlink or forward link. The (e / g)NodeB or their functionality may be implemented by any node, host, server, or access point, or other entity suitable for such use.

[0031] A communication system may include two or more (e / g)NodeBs, in which case the (e / g)NodeBs may also be configured to communicate with each other via wired or wireless links designed for that purpose. These links may be used for signaling purposes. An (e / g)NodeB may be a computing device configured to control the radio resources of the communication system to which it is connected.

[0032] (e / g) A NodeB may also be referred to as a base station, an access point, or any other type of interfacing device, including a relay station, capable of operating in a wireless environment. (e / g) A NodeB may include or be coupled to a transceiver. (e / g) A connection may be provided from the transceiver of the NodeB to an antenna unit that establishes a bidirectional wireless link to a user device.

[0033] The antenna unit may include multiple antennas or antenna elements. (e / g) The NodeB may be further connected to a core network 110 (CN or Next Generation Core NGC). Depending on the system, the counterpart on the CN side may be a Serving Gateway (S-GW, which routes and forwards user data packets), a Packet Data Network Gateway (P-GW) for providing connectivity of user devices (UEs) to external packet data networks, a Mobility Management Entity (MME), an Access and Mobility Management Function (AMF), or a Location Management Function (LMF), etc.

[0034] A user device (also referred to as UE, user equipment, user terminal, terminal device, etc.) illustrates one type of device to which resources over the air interface may be allocated and assigned, and therefore any features described herein in conjunction with a user device may also be implemented in conjunction with a corresponding device such as a relay node.

[0035] An example of such a relay node may be a Layer 3 relay (self-backhauling relay) towards the base station. A self-backhauling relay node may also be called an integrated access and backhaul (IAB) node. An IAB node may include two logical parts: a mobile terminal (MT) part that handles the backhaul link (i.e., the link between the IAB node and a donor node, known as a parent node), and a distributed unit (DU) part that handles the access link (i.e., the child link between the IAB node and UEs and / or between the IAB node and other IAB nodes (multi-hop scenarios).

[0036] An example of such a relay node may be a Layer 1 relay, called a repeater, which can amplify signals received from a base station or user device to a user device or base station.

[0037] A user device may refer to portable computing devices including, but not limited to, the following types of devices: wireless mobile communication devices that operate with or without a subscriber identity module (SIM), including mobile stations (cell phones), smartphones, personal digital assistants (PDAs), handsets, devices that use wireless modems (such as alerting or measuring devices), laptops and / or touchscreen computers, tablets, game consoles, notebooks, and multimedia devices. A user device may also be referred to as user equipment (UE) or terminal device.

[0038] A user device may also be almost exclusively an uplink-only device, an example of which may be a camera or camcorder that loads images or video clips onto the network.

[0039] The user device may also be a device capable of operating in an Internet of Things (IoT) network, which is a scenario in which objects may be given the ability to transfer data over a network without the need for human-to-human or human-to-computer interaction. The user device may also utilize the cloud.

[0040] In some applications, the user device may include a small portable device (such as a watch, earphones, or glasses) with a wireless portion, and computations may be performed in the cloud. The user device (or in some exemplary embodiments, a Layer 3 relay node) may be configured to perform one or more of the user equipment functions. A user device may also be called a subscriber unit, mobile station, remote terminal, access terminal, user terminal, terminal device, or user equipment (UE), to name a few.

[0041] The various techniques described herein can also be applied to cyber-physical systems (CPSs), systems consisting of cooperating computational elements that control physical entities. CPSs may enable the implementation and utilization of vast amounts of interconnected ICT devices (sensors, actuators, processors, microcontrollers, etc.) embedded in physical objects at various locations. Mobile cyber-physical systems, in which the physical system in question may have inherent mobility, are a subcategory of cyber-physical systems. Examples of mobile physical systems include mobile robotics and electronic devices carried by humans or animals.

[0042] Additionally, although the device is depicted as a single entity, different units, processors and / or memory units (not all shown in FIG. 1) may be implemented.

[0043] Wireless networks, for example fifth generation cellular networks (5G), use multiple input multiple output (MIMO) antennas, many more base stations or nodes than LTE, including macro sites working in conjunction with smaller stations (the so-called small cell concept), making it possible to utilize a variety of radio technologies depending on service demand, use case and / or available spectrum.

[0044] Mobile communications, for example, 5G systems (5GS), can support a wide variety of use cases and related applications, including video streaming, augmented reality, vehicle safety, various sensor and real-time control, various modes of data sharing, and various forms of machine-type applications ((massive) machine-type communications (mMTC)).

[0045] 5G can be expected to have multiple air interfaces, namely below 6 GHz, centimeter wave, and millimeter wave, and to be able to integrate with existing legacy radio access technologies such as LTE. The integration with LTE, at least in the early stages, can be implemented as a system in which macro coverage can be provided by LTE and 5G air interface access can come from small cells through aggregation to LTE. In other words, 5G can support both inter-RAT operation (e.g., LTE-5G) and inter-RI operation (inter-air interface operation, such as below 6 GHz-centimeter wave, below 6 GHz-centimeter wave-mm wave, etc.).

[0046] One concept that is likely to be used in 5G networks may be network slicing, in which multiple independent and dedicated virtual sub-networks (network instances) may be created within substantially the same infrastructure to run services with different requirements for latency, reliability, throughput and mobility.

[0047] The architecture in an LTE network may be fully distributed in the radio and fully centralized in the core network. Low latency applications and services in 5G may need to bring content closer to the radio, which brings about local breakout and multi-access edge computing (MEC).

[0048] 5G can enable analytics and knowledge generation to occur at the source of data. This approach may require leveraging resources that may not be constantly connected to the network, such as laptops, smartphones, tablets, and sensors. MEC can provide a distributed computing environment for application and service hosting. It may also have the ability to store and process content in close proximity to cellular subscribers for faster response times.

[0049] Edge computing can cover a wide variety of technologies, such as wireless sensor networks, mobile data acquisition, mobile signature analysis, collaborative distributed peer-to-peer ad hoc networking and processing, which can also be categorized as local cloud / fog computing and grid / mesh computing, due computing, mobile edge computing, cloudlets, distributed data storage and retrieval, autonomous self-healing networks, remote cloud services, augmented and virtual reality, data caching, Internet of Things (massive connectivity and / or latency critical), critical communications (autonomous vehicles, road safety, real-time analytics, time-critical control, medical applications), etc.

[0050] The communications system may also be capable of communicating with or using services provided by other networks, such as the public switched telephone network or the Internet 112. The communications network may also be capable of supporting the use of cloud services, e.g., at least a portion of the core network operations may be performed as cloud services (this is depicted in FIG. 1 by "cloud" 114). The communications system may also include a central control entity, etc., that provides facilities for networks of different operators to cooperate, e.g., in spectrum sharing.

[0051] An edge cloud can participate in a radio access network (RAN) by utilizing network function virtualization (NFV) and software-defined networking (SDN). Using an edge cloud may mean that access node operations are performed, at least in part, within a server, host, or node operatively coupled to a remote radio head (RRH) or radio unit (RU) or base station including the radio portion. It may also be possible for node operations to be distributed among multiple servers, nodes, or hosts. Executing RAN real-time functions on the RAN side (in the distributed unit DU 104) and non-real-time functions in a centralized manner (in the central unit CU 108) may be enabled, for example, by applying a cloud RAN architecture.

[0052] It should also be understood that the distribution of work between core network operations and base station operations may differ from that of LTE, or may even not exist. Some other technological advances that may be used may be big data and all-IP, which may change the way networks are built and managed. 5G (or New Radio, NR) networks may be designed to support multiple hierarchies, where MEC servers may be located between the core and base stations or nodeBs (gNBs). It should be appreciated that MEC may also be applied to 4G networks.

[0053] 5G may also utilize extraterrestrial communications, such as satellite communications, to augment or complement 5G service coverage, for example, by providing backhauling. Possible use cases may be providing service continuity for machine-to-machine (M2M) or Internet of Things (IoT) devices or passengers aboard vehicles, or ensuring service availability for critical communications and future rail, maritime, and aviation communications. Satellite communications may utilize geostationary Earth orbit (GEO) satellite systems, but may also utilize low Earth orbit (LEO) satellite systems, particularly megaconstellations (systems in which hundreds of (nano)satellites are deployed). At least one satellite 106 in a megaconstellation may cover several satellite-enabled network entities, creating ground cells. Ground cells may be created through terrestrial relay nodes 104 or by gNBs located on the ground or within the satellites.

[0054] It will be apparent to those skilled in the art that the depicted system is only one example of a part of a radio access system, and that in practice the system may include multiple (e / g)NodeBs, a user device may access multiple radio cells, and the system may also include other devices such as physical layer relay nodes or other network elements, etc. At least one of the (e / g)NodeBs may be a home (e / g)nodeB.

[0055] Furthermore, the (e / g)nodeB or base station can also be divided into a radio unit (RU) including a radio transceiver (TRX), i.e., a transmitter (Tx) and a receiver (Rx), one or more distributed units (DUs) that can be used for so-called Layer 1 (L1) processing and real-time Layer 2 (L2) processing, and a central unit (CU) (also known as a centralized unit) that can be used for non-real-time L2 and Layer 3 (L3) processing. The CU can be connected to one or more DUs, for example, by using an F1 interface. Such division can enable centralization of the CU to the cell site and the DU, while the DU can be more distributed or even remain at the cell site. Both the CU and the DU may also be referred to as a baseband or baseband unit (BBU). The CU and the DU may also be included in a wireless access point (RAP).

[0056] A CU can be defined as a logical node that hosts higher layer protocols such as Radio Resource Control (RRC), Service Data Adaptation Protocol (SDAP) and / or Packet Data Convergence Protocol (PDCP) of an (e / g)nodeB or base station. A DU can be defined as a logical node that hosts the Radio Link Control (RLC), Medium Access Control (MAC) and / or Physical (PHY) layers of an (e / g)nodeB or base station.

[0057] The operation of the DU may be controlled, at least in part, by the CU. The CU may include a control plane (CU-CP), which may be defined as a logical node that hosts the control plane portion of the RRC and PDCP protocols of the CU of an (e / g)nodeB or base station. The CU may further include a user plane (CU-UP), which may be defined as a logical node that hosts the user plane portion of the PDCP and SDAP protocols of the CU of an (e / g)nodeB or base station.

[0058] A cloud computing platform may also be used to run the CU and / or DU. The CU may run within the cloud computing platform, which may be referred to as a virtualized CU (vCU). In addition to the vCU, there may also be a virtualized DU (vDU) running within the cloud computing platform.

[0059] Furthermore, combinations may also exist, where the DU may use so-called bare metal solutions, for example application specific integrated circuits (ASICs) or customer specific standard products (CSSPs) system-on-chip (SoC) solutions. It should also be understood that the base station units mentioned above, or the distribution of work between different core network operations and base station operations, may differ.

[0060] Additionally, multiple different types of radio cells and multiple radio cells may be provided in a geographical area of ​​a wireless communication system. A radio cell may be a macrocell (or umbrella cell), which may be a large cell with a diameter of up to tens of kilometers, or a smaller cell such as a micro, femto, or picocell. The (e / g)NodeB in FIG. 1 can provide these cells of any type. A cellular wireless system may be implemented as a multi-tier network including several types of cells. In a multi-tier network, one access node may provide one or more cells of one type, and therefore multiple (e / g)NodeBs may be needed to provide such a network structure.

[0061] To meet the need to improve the deployment and performance of communication systems, the concept of "Plug and Play" (e / g) NodeB may be introduced. A network that may be able to use "Plug and Play" (e / g) NodeB may include a Home NodeB Gateway, or HNB-GW (not shown in FIG. 1), in addition to a Home (e / g) NodeB (H(e / g)nodeB). The HNB Gateway (HNB-GW), which may be installed in an operator's network, can aggregate traffic from multiple HNBs back to the core network.

[0062] Coverage is a fundamental aspect of cellular network deployment. However, full-stack cell establishment (i.e., dense deployment) may not always be possible (e.g., backhaul is not available) or feasible. To overcome such challenges, new types of network nodes are being considered to increase mobile operators' flexibility regarding their network deployment.

[0063] 5G New Radio (NR) Release 16 offers one such option for flexible RAN expansion, referred to as Integrated Access and Backhaul (IAB). IAB is a multi-hop approach to network deployment that enables the deployment of base stations with wireless backhaul transport. It works by having a percentage of deployed base stations act as IAB donors using fiber / wired connections. The remaining base stations without wired connections are called IAB nodes, which may be wirelessly connected to IAB donors and / or other IAB nodes via wireless backhaul links.

[0064] An IAB node is a relay node that comprises a distributed unit (DU) component that allows it to appear as a normal cell to the UEs it serves, and a mobile terminal (MT) component that inherits many of the characteristics of a normal UE connecting to its parent node. Both IAB nodes and IAB donors generate uniform cellular coverage areas and appear identical to UEs within those coverage areas. Thus, the advantage of IAB is that it allows for flexible and dense deployment of NR cells without proportionally increasing the density of the transport network. Various deployment scenarios can be envisioned for IAB, including outdoor small cell deployments, indoors, or even supporting mobile relays (e.g., on buses or trains).

[0065] Another type of network node is the radio frequency (RF) repeater. RF repeaters are used in 2G, 3G, and 4G deployments to complement the coverage provided by regular full-stack cells with various transmit power characteristics. The main advantages of RF repeaters are their ease of deployment and the fact that they do not increase latency. The main disadvantage is that they amplify signals and noise and therefore may contribute to increased interference (pollution) within the system.

[0066] Within RF repeaters, there are different categories depending on their power characteristics and the amount of spectrum they are configured to amplify (e.g., single-band, multi-band, etc.). RF repeaters are non-regenerative relay nodes and may amplify and forward anything they receive. RF repeaters may be full-duplex nodes that do not distinguish between uplink (UL) and downlink (DL) in terms of transmission or reception.

[0067] As 5G NR moves to higher frequencies (approximately 6 GHz for deployments of Frequency Range 1, FR1, and above 24 GHz for Frequency Range 2, FR2), propagation conditions deteriorate compared to lower frequencies, thus exacerbating coverage challenges. As a result, cells may need to be made even denser. Multi-antenna techniques consisting of massive MIMO for FR1 and analog beamforming for FR2 help address the more difficult propagation conditions of these higher frequencies. Frequency bands defined in this high frequency regime may use time division duplexing (TDD).

[0068] Another common characteristic of NR systems is the use of multi-beam operation with associated beam management in FR2. Because RF repeaters may not be capable of providing beam management for NR devices, it is envisioned that NR will support a new class of relays called smart repeaters (SRs). Smart repeaters support advanced beam management techniques and can perform advanced time, frequency, and directional (uplink and / or downlink) resource amplification and forwarding.

[0069] 2 shows a high-level schematic diagram of a smart repeater (SR) architecture with a dedicated link from a gNB to the SR and an analog pass-through signal from the gNB 201 to the UE 203. The smart repeater 202 selects one active backhaul beam for the backhaul link 211 between the gNB 201 and the smart repeater 202, and one active access beam for the access link 212 between the smart repeater 202 and the UE 203.

[0070] As shown in Figure 2, the smart repeater benefits from a dedicated control channel 221 to communicate with the gNB. The control channel 221 can be deployed as a legacy 3GPP 5G NR gNB-UE interface or as a new gNB-SR interface.

[0071] Additionally, there may be a legacy 5G NR gNB-UE interface 222 between the smart repeater 202 and the UE 203. User signals (data) may be received, amplified, and transmitted to the UE 203 over the appropriate SR access beam without decoding or any digital modification. Thus, the user signals are transparent to the UE 203, and as a result, the UE 203 assumes it is directly connected to the gNB 201 and is unaware that data is coming in through the smart repeater 202.

[0072] The smart repeater's ability to transmit time / frequency preconfigured beamformed signals significantly reduces the interference generated by neighboring nodes and reduces the spatial loss of transmitted energy. This is therefore advantageous compared to RF repeaters, which may amplify received signals (including interference) using omnidirectional antennas. Compared to IAB nodes, smart repeaters benefit from lower hardware and software complexity and reduced latency.

[0073] Beam-based communications is one of the key enablers of 5G NR for enhancing network capacity, throughput, and reliability. Transmission / reception through directional narrow beams generated by high-dimensional phased arrays improves signal quality at the desired UE, reduces interference across neighboring nodes, and compensates for additional propagation path loss due to the use of higher carrier frequencies (e.g., FR2). Herein, a beam may also be referred to as a spatial filter.

[0074] Beamforming can be defined as any technique that allows controlled focusing of transmit and / or receive energy to a spatial support when compared to an omnidirectional baseline. Examples of spatial supports are directions / solid angles, spatial volumes, and other (at least partially) orthogonal fields in space. Controlled beamforming means that it is possible to focus energy to / from different spatial supports that may partially overlap.

[0075] A beam in this application defines a spatial resource. A beam is also defined as a spatial filter. A beam is transmitted or received to / from a certain spatial direction, and the beam is formed by using a set of antennas controlled by a controller (e.g., a baseband controller).

[0076] The shape and direction of the beam may be determined by which type of function is used. This type of special function may be called a beamforming function, a mapping function, or a spatial filter. When a UE or a gNB applies the same spatial filter, this means that it forms the same beam, i.e., the antenna radiation pattern has the same direction of the beam, the same shape, and / or the same power.

[0077] In NR, multiple antennas may be utilized by the base station and UE to achieve highly directional beamforming transmission and reception between the base station and the UE. Hybrid beamforming is a combination of analog beamforming, which applies different phase adjusters and / or amplification weights to each antenna panel, and digital beamforming, which applies different digital precoders across the panels. To fully exploit the beamforming gain, low-latency beam management techniques may be used for initial access, beam tracking, beam / radio link failure recovery, and during handover procedures. In NR, beam management is a set of Layer 1 (PHY) and / or Layer 2 (MAC) procedures that primarily rely on measurements of reference signals, such as synchronization signal blocks (SSBs) and channel state information reference signals (CSI-RSs) in the downlink and measurement reference signals (SRSs) in the uplink.

[0078] Figure 3 shows a 5G NR beam refinement procedure for initial beam pair establishment between a gNB and a smart repeater. For a scenario in which the UE is connected to the gNB through SR amplification and forwarding (note that SR is transparent to the UE), it is assumed that 5G NR beam pair selection between the gNB, SR, and UE includes the following stages: a first stage called gNB-SR-P1 for initial gNB beam acquisition (via SSB) as shown in block 301 of Figure 3; a second stage called gNB-SR-P2 for gNB beam refinement (e.g., via CSI-RS) as shown in block 302 of Figure 3; and a third stage called gNB-SR-P3 for SR beam refinement as shown in block 303 of Figure 3.

[0079] Figure 4 shows an example of the gNB-SR-P1 phase for beam pair establishment between a serving gNB 401 and a smart repeater 402. The gNB-SR-P1 involves a directional SSB beam transmission from the gNB 401 for initial connection establishment.

[0080] When an idle-mode smart repeater 402 or UE desires to establish a connection to a gNB 401, it acquires frame synchronization information and performs a random access (RA) procedure. To this end, as presented in FIG. 4, the gNB broadcasts a set of wide SSB beams (so-called SSB bursts) in multiple different directions, each carrying dedicated information such as a primary synchronization signal (PSS), a secondary synchronization signal (SSS), a physical broadcast channel (PBCH), a demodulation reference signal (DMRS), etc. For example, a given SSB burst may have a length of 5 ms and contain up to 64 SSBs (within FR2). Depending on the network configuration, the SSB bursts may have a periodicity of 5 to 160 ms.

[0081] In the first step, smart repeater 402 establishes a connection with gNB 401 to initialize the gNB-SR control channel. SR may use the 5G NR Uu interface for this step. Smart repeater 402 measures the reference signal received power (RSRP) of the beams in the SSB burst through a static wide backhaul (BH) receive beam, selects the best SSB beam based on the measurement, decodes cell-specific information, and initiates the initial connection establishment procedure toward gNB 401.

[0082] After receiving the SR-related configuration from gNB 401, smart repeater 402 amplifies the SSB and transmits (a set of) the SSB toward the UE using its wide-access beam. Smart repeater 402 also relays, for example, corresponding UL Random Access Channel (RACH) transmission opportunities from the UE to the gNB, so that the UE can trigger an initial access procedure and establish an initial connection with gNB 401.

[0083] Figure 5 shows an example of the gNB-SR-P2 stage, in which gNB 501 performs narrow CSI-RS beam transmission for backhaul beam pair establishment between gNB 501 and smart repeater 502.

[0084] After a successful initial access connection (gNB-SR-P1), the gNB 501 may attempt to further boost the throughput of the backhaul link by communicating with the smart repeater 502 via narrower beams. To this end, a set of finer (narrower) CSI-RS beams (e.g., CSI-RS#0.0, CSI-RS#1.0, CSI-RS#2.0, and CSI-RS#3.0 in FIG. 5) may be configured and transmitted within the spatial profile of the corresponding parent SSB beam. The smart repeater 502 measures the CSI-RS beams and reports the best CSI-RS beam(s) based on the measurements to the gNB 501.

[0085] For example, smart repeater 502 may report CSI-RS beam #2.0 as the best CSI-RS beam. gNB 501 may select the best CSI-RS beam (corresponding to the highest RSRP value) as the serving beam and provide smart repeater 502 with beam failure recovery (BFR) configurations of other beams.

[0086] Figure 6 shows an example of the gNB-SR-P3 stage for SR backhaul receive beam refinement. The smart repeater 602 can adjust its backhaul narrow receive beam (SR_BH), while the gNB 601 maintains and repeats a fixed CSI-RS. For example, if CSI-RS beam #2.0 was the best CSI-RS beam reported by the smart repeater in the gNB-SR-P2 stage, the gNB 601 may transmit a CSI-RS repetition of CSI-RS #2.0, while the smart repeater 602 sweeps its backhaul receive beams (e.g., SR_BH#0, SR_BH#1, SR_BH#2, and SR_BH#3 in Figure 6).

[0087] To perform its narrow beam alignment procedure, the smart repeater 602 may rely on reference signals associated with a non-zero power channel state information reference signal (NZP-CSI-RS) resource set having the same beam identifier (ID) from the gNB 601 and configured with the upper layer parameter "repetition" set to "on."

[0088] For example, the gNB 601 may indicate to the smart repeater 602 in the "nzp-CSI-RS-Resources" information element the index of the CSI-RS resource set whose transmission will be repeated and set the "Repetition" information element to "On." The repetition parameter indicates to the smart repeater 601 that the NZP-CSI-RS resource set is transmitted using the same downlink spatial filter. Furthermore, the "NZP-CSI-RS-ResourceId" information element may be used to identify the NZP-CSI-RS resources that belong to a particular NZP-CSI-RS resource set. Scheduling of such reference signals can be fully controlled by the gNB 601. At this stage, the smart repeater 602 may not report measurements to the gNB 601.

[0089] Figure 7 shows an example of SR access beam selection. SR access beam management for a UE 703 can be performed via a stage called SR-UE-P2 as presented in Figure 7. The gNB 701 continuously transmits bursts of CSI-RS signals from the gNB to the SR that share the same radiation pattern (e.g., spatial filter / support or angular direction) but have different beam IDs (e.g., CSI-RS #2.0, #2.1, #2.2, and #2.3 in Figure 7).

[0090] The smart repeater 702 receives CSI-RS signals using the same SR backhaul beam (e.g., SR_BH#1) and performs access beam sweeping by mapping each gNB CSI-RS signal to an SR access beam. The smart repeater 702 transmits the received CSI-RS toward the UE 703.

[0091] For example, the smart repeater 702 can map a first CSI-RS (CSI-RS#2.0) to a first SR access beam (SR_AC#0), a second CSI-RS (CSI-RS#2.1) to a second SR access beam (SR_AC#1), a third CSI-RS (CSI-RS#2.2) to a third SR access beam (SR_AC#2), and a fourth CSI-RS (CSI-RS#2.3) to a fourth SR access beam (SR_AC#3). In other words, the CSI-RS signals are repeated by the smart repeater 702 on the SR-UE access (SR_AC) link using different spatial filters (angular directions).

[0092] The UE 703 measures the SR access beams and reports one or more best CSI-RS beam IDs (and corresponding RSRP values) via the SR uplink path to the gNB 701. The gNB 701 then informs the SR 702 about the best UE-measured CSI-RS beam ID (e.g., CSI-RS#2.2).

[0093] Note that there is no direct communication link between the smart repeater 702 and the UE 703. Based on the applied mapping between the CSI-RS beam ID and the SR access beam, the smart repeater 702 determines the best SR access beam (e.g., SR_AC#2) for the UE.

[0094] To enhance coverage, maximize throughput, and reduce interference, smart repeaters can be equipped with multiple antennas and large beamforming capabilities on both the backhaul and access sides, exhibiting several beam configurations. For example, a smart repeater can exhibit eight or more different beam configurations on each side exposed in an NR framework, or even more if base station hardware is used. For example, for FR2, there can be 32 or 64 improved beams on the access side, and a similar number on the backhaul side.

[0095] As mentioned above, according to the present solution, determining the optimal SR backhaul beam (gNB-SR-P3 phase) and SR access beam (SR-UE-P2 phase) may require the gNB to transmit two separate CSI-RS sets. Such a large number of gNB CSI-RS transmissions is a timely and resource-consuming procedure, which may be problematic, for example, in scenarios where the cell is under load.

[0096] Furthermore, for mobile smart repeaters (e.g., smart repeaters installed on the roof of a bus, train, or car, or cases with mobile SR-mobile SR communication), and / or due to UE mobility and rotation, it becomes necessary to frequently realign the SR beam, which significantly increases the required periodicity and resource usage of CSI-RS transmissions.

[0097] As a more visual example, one can imagine a train with a smart repeater on the roof. Here, the SR-UE enhanced beam requires constant tracking / measurement as the UE rotates and moves. At the same time, the gNB-SR enhanced beam requires constant tracking / measurement as the train moves. The same applies to UEs served by stationary but mobile smart repeaters, such as UEs outside a train or an unmanned aerial vehicle (UAV) or drone acting as a smart repeater.

[0098] One solution to reduce this overhead is to simultaneously implement gNB-SR-P3 and SR-UE-P2 using one CSI-RS resource set. This solution includes: the repeater receiving access link information from the access point via a backhaul link, where the access link information includes received power of one or more reference signals or an indication of a spatial filter for the access link, and obtaining at least one spatial filter pair for the backhaul link and the access link based at least in part on the access link information. The access point may be a gNB or any network node supporting radio access functionality.

[0099] It should be noted that the CSI-RS in this application is an example, and any other reference signal (RS) may alternatively be used for beam refinement purposes.

[0100] FIG. 8 illustrates a simultaneous gNB-SR-P3 and SR-UE-P2 beam refinement procedure for the same CSI-RS resource set, according to an example embodiment.

[0101] 8, gNB 801 transmits a set of CSI-RS signals with the same angular direction but different CSI-RS beam IDs (e.g., CSI-RS #2.0, #2.1, #2.2, and #2.3). Smart repeater 802 creates a mapping between individual SR backhaul beams and SR access beams.

[0102] For example, the smart repeater 802 may map a first CSI-RS (CSI-RS#2.0) to a first backhaul beam (SR_BH#0) and a first access beam (SR_AC#0), a second CSI-RS (CSI-RS#2.1) to a second backhaul beam (SR_BH#1) and a second access beam (SR_AC#1), a third CSI-RS (CSI-RS#2.2) to a third backhaul beam (SR_BH#2) and a third access beam (SR_AC#2), and a fourth CSI-RS (CSI-RS#2.3) to a fourth backhaul beam (SR_BH#3) and a fourth access beam (SR_AC#3).

[0103] When there is a new CSI-RS transmission, the smart repeater 802 performs a backhaul beam sweep and measures the RSRP of the SR backhaul beams (e.g., SR_BH#0, #1, #2, and #3). At the same time, the smart repeater 802 amplifies the received signals at a fixed predetermined level and transmits them via the corresponding SR access beams (e.g., SR_AC#0, #1, #2, and #3) according to the mapping, so that the UE 803 can also measure the beams.

[0104] In the example of Figure 8, for simplicity, the number of gNB CSI-RS transmissions is equal to the number of SR backhaul beams and the number of SR access beams, and the number of SR backhaul beams is equal to the number of SR access beams. However, for scenarios where the number of backhaul beams and the number of access beams are different, the number of CSI-RS transmissions may be equal to the maximum number of access or backhaul beams, and the smart repeater may retransmit via some of those beams.

[0105] However, one of the main challenges of applying the above solution in Figure 8 is suboptimal access beam selection and reporting by the UE due to the transmission of non-normalized access beams with different power levels. This occurs when the smart repeater amplifies the received signal with the same power amplification (PA) gain (e.g., 70 dB), and therefore the characteristics of the backhaul beam (e.g., RSRP) affect the transmit power of the access beam and, therefore, the access beam sweep evaluation by the UE. Because backhaul beam measurement and amplification are substantially simultaneous (e.g., with a latency of several nanoseconds), the smart repeater may not be able to quickly measure and apply individual amplification gains for each SR access beam to compensate for the different SR backhaul beam receive RSRP offset values.

[0106] Table 1 below shows an example of UE false detection of the best SR access beam when the smart repeater 802 amplifies all CSI-RS signals with the same PA gain, applying the configuration of Figure 8, where the backhaul beam quality affects the UE-measured RSRP of the access beam. In other words, the received signal quality of the SR backhaul beam affects the transmit power of the SR access beam and, therefore, the UE-measured RSRP value.

[0107] As a result, in the example of Table 1, the UE reports CSI-RS#2.1 corresponding to SR_AC#1 as the best measured beam (having the highest UE measured RSRP). However, in this example, SR_AC#2 is actually the best SR access beam (SR_AC#2 provides a path gain of -55 dB, which is 5 dB higher than that of SR_AC#1, which has a path gain of -60 dB), and SR_BH#1 is the best SR backhaul beam (highest SR_BH measured RSRP). In other words, in this example, SR_BH#1 and SR_AC#2 are the optimal SR beam pair for the backhaul link and the access link.

[0108] [Table 1]

[0109] Some exemplary embodiments enhance the SR beam refinement procedure by conducting both the gNB-SR-P3 and SR-UE-P2 beam search phases on the same CSI-RS resource set transmitted by the gNB. In other words, some exemplary embodiments enable both the best backhaul beam for a smart repeater and the best access beam for a given UE to be determined by using the same CSI-RS resource set.

[0110] In some exemplary embodiments, a smart repeater can simultaneously fine-tune its backhaul and access beams by using one CSI-RS resource set transmitted for SR-UE-P2, thus avoiding the need for dedicated transmission of CSI-RS repetitions for gNB-SR-P3. Thus, the smart repeater can search for its best beam faster, which reduces network resource consumption and beam search latency.

[0111] Some example embodiments enable having information of both the SR measured RSRP of the backhaul beam and the UE measured RSRP of the access beam within one entity (gNB or smart repeater) to compensate for the effect of the backhaul beam on the UE measured access beam and appropriately determine the optimal SR access beam for communicating with the UE over the access link.

[0112] To achieve this goal, the smart repeater can amplify the incoming gNB backhaul signal by an equal amount, regardless of the selected SR backhaul beam. At the same time, the smart repeater measures the power of the gNB CSI-RS transmitted over the same spatial support. Using this knowledge and reports from the UE, either the gNB or the smart repeater can compensate the UE measurements to determine the best CSI-RS beam ID and SR access beam for communicating to the UE.

[0113] Table 2 below shows an example of obtaining the optimal SR access beam according to an exemplary embodiment. This example applies the configuration of Figure 8, and the gNB 801 or smart repeater 802 can determine the CSI-RS ID of the appropriate SR access beam based on measurement knowledge of the SR backhaul and access beams.

[0114] In this example, UE 803 may not be able to reliably determine the best SR access beam because the channel between gNB 801 and smart repeater 802 is not constant and therefore measurements are not directly comparable. Therefore, UE 803 reports a suboptimal CSI-RS beam ID (CSI-RS#2.1 corresponding to SR_AC#1) to the network because the non-normalized CSI-RS signals transmitted from the SR access beam have different transmit power levels caused by the unequal signal quality received through the SR backhaul beam.

[0115] In this example, SR_AC#2 is the optimal normalized SR beam for the access link (SR_AC#2 provides a path gain of -55 dB, which is 5 dB higher than that of SR_AC#1, which has a path gain of -60 dB). Having measurements of both the SR access beam and the backhaul beam allows the gNB or smart repeater to determine the actual normalized value of the path gain (presented in the "Compensated UE-Reported RSRP" column in Table 2) for each SR access beam by subtracting the delta-offset RSRP value of the SR backhaul beam (calculated relative to the lowest measured SR backhaul beam) from the UE-measured SR access beam, thereby compensating the UE measurement results and avoiding the above problem. By doing this, as can be seen from Table 2, the highest value in the "Compensated UE-Reported RSRP" column (CSI-RS#2.2, corresponding to SR_AC#2) represents the optimal normalized SR access beam.

[0116] [Table 2]

[0117] FIG. 9 shows a signaling diagram according to an example embodiment, in which a reference signal identifier (e.g., CSI-RS beam ID) corresponding to the best SR access beam (spatial filter) is obtained by an access point (e.g., gNB) based on RSRP measurements reported by both smart repeaters and UEs.

[0118] 9, in step 901, a smart repeater (SR) and at least one UE establish an initial connection to an access point (e.g., gNB) using a wide SR spatial filter (beam). The smart repeater may also inform the access point regarding the number of backhaul beams and access beams of the smart repeater.

[0119] In step 902, the smart repeater can transmit capability information to the access point via a backhaul link between the smart repeater and the access point, the capability information including a capability instruction for performing a backhaul-access integrated spatial filter (beam) refinement procedure in the smart repeater. For example, the capability information can be transmitted in a Medium Access Control (MAC) control element (CE) or a Radio Resource Control (RRC) in the uplink.

[0120] The capability information helps the access point not to schedule dedicated reference signal repetitions specifically for gNB-SR-P3, but to wait until at least one UE is available for SR / gNB-UE-P2. If a UE is not available or cannot be scheduled within a reasonable time window (e.g., half the L1 / RSRP CSI-RS period), the access point can revert to dedicated gNB-SR-P3.

[0121] In step 903, the access point may transmit a backhaul resource configuration to the smart repeater via a backhaul link, the backhaul resource configuration indicating one or more time-frequency resources to be used for the first reference signal set.

[0122] Through the backhaul resource configuration, the access point configures the smart repeater for access beam sweeping. For example, the access point can semi-statically or periodically transmit the backhaul resource configuration to the smart repeater to indicate the time division duplexing (TDD) time slots and reference signal resource structure to be used for each active reference signal beam of the access point. Through the backhaul resource configuration, the access point can also configure the smart repeater to report RSRP measurements of the SR backhaul spatial filter (backhaul beam).

[0123] In step 904, the access point may configure at least one UE for reference signal beam measurements and reporting.

[0124] In step 905, the access point may transmit a first reference signal (RS) set to the smart repeater using the same spatial filter (angular direction) but a different identifier (e.g., beam ID) to simulate a sweep. Although the access point exhibits repetition-like behavior, the repetition flag may not be set in the UE RS resource RRM configuration. The first reference signal set may include at least one of a channel state information reference signal (CSI-RS), a primary synchronization signal (PSS), a secondary synchronization signal (SSS), or a tracking reference signal (TRS).

[0125] In step 906, the smart repeater may amplify and transmit a second reference signal set to at least one UE via the access link using a different spatial filter, where the second reference signal set corresponds to the first reference signal set. In other words, the smart repeater may amplify and forward the received first reference signal set (i.e., the second reference signal set may be the same as the first reference signal set). When transmitting the second reference signal set via the access link, the smart repeater may amplify each reference signal in the second reference signal set by an equal amount (i.e., with the same amplification gain).

[0126] In step 907, the smart repeater may sweep its backhaul (BH) spatial filter (backhaul beam) and measure the received power (e.g., RSRP) of each reference signal (resource) of the first reference signal set on the backhaul spatial filter to obtain a first set of measurement results indicating the received power of the first reference signal set.

[0127] In step 908, the smart repeater can map the first reference signal set to a set of spatial filters used to transmit the second reference signal set over the access link. In other words, the smart repeater can map each reference signal of the received first reference signal set to a spatial filter (beam) of the access (AC) link.

[0128] In step 909, the smart repeater may obtain or select a spatial filter (beam) for the backhaul link based on the first set of measurements obtained in step 907. For example, the smart repeater may select the spatial filter with the highest measured RSRP.

[0129] In step 910, at least one UE may measure the received power (e.g., RSRP) of a second set of reference signals received through a different spatial filter over the access link to obtain a second set of measurement results indicative of the received power of the second set of reference signals.

[0130] In step 911, the smart repeater may send a report to the access point via a backhaul link, the report including a first set of measurement results indicating the received power of a first set of reference signals.

[0131] In other words, the smart repeater reports an RS identifier (e.g., an index of each RS resource in the configured RS resource set) and the corresponding measured power (e.g., L1 / RSRP) value to the access point. In one example, the actual value of each measured RSRP may be reported. In another example, an offset value for the highest or lowest measured spatial filter (beam) may be reported.

[0132] In step 912, at least one UE may send a report to the access point to report the second set of measurement results obtained in step 910. In other words, the UE reports the measurement spatial filter and the corresponding measurement RSRP value (or offset to the best beam) to the access point through the uplink path amplified by the smart repeater.

[0133] In step 913, the access point can compensate for the second set of measurements based on the first set of measurements. In other words, based on the first set of measurements and the second set of measurements, the access point compensates for the effect of the backhaul spatial filter sweep (beam sweep) of step 907 on the measurements of the access link spatial filter (beam) performed by the UE in step 910.

[0134] For example, for each reference signal n received by the smart repeater through backhaul link spatial filter i and transmitted through access link spatial filter j, the access point can calculate a delta offset relative to the lowest measurement value in the first set of measurements as follows:

[0135]

number

[0136] During the ceremony,

number

number

[0137] The access point may compensate the RSRP value of the second measurement set by the calculated delta offset as follows:

[0138]

number

[0139] In step 914, the access point obtains or determines access link information for the smart repeater based at least in part on the compensated second set of measurements, the access link information including an indication of a spatial filter for the access link.

[0140] The indication of the spatial filters for the access link may include one or more spatial filters to be used across the access link, or a pair of spatial filters between the backhaul link and the access link. The indication may include, for example, an identifier of a reference signal from the first reference signal set that would have provided the highest RSRP if the second reference signal set had been transmitted with a normalized transmit power (from an SR perspective). For example, an identifier of a reference signal n * (According to the mapping from step 908, the access link spatial filter j * ) can be obtained as follows:

[0141]

number

[0142] In step 915, the access point sends the access link information to the smart repeater.

[0143] In step 916, based on the access link information and the applied mapping of step 908, the smart repeater obtains or determines a spatial filter (beam) for communicating with at least one UE over the access link. Thus, the smart repeater obtains at least one spatial filter pair (beam pair) for the backhaul link and the access link based at least in part on the access link information.

[0144] In step 917, the smart repeater can communicate with at least one UE and the access point via the obtained at least one spatial filter pair. For example, the smart repeater can receive one or more signals from the access point via the spatial filter obtained for the backhaul link in step 909, amplify the one or more signals, and transmit them to the at least one UE via the spatial filter obtained for the access link in step 916.

[0145] Alternatively or additionally, the smart repeater may receive one or more signals from at least one UE via the spatial filter obtained for the access link in step 916, amplify the one or more signals, and transmit them to the access point via the spatial filter obtained for the backhaul link in step 909.

[0146] 10 shows a signaling diagram according to another exemplary embodiment, in which the best access beam is obtained by a smart repeater. In this exemplary embodiment, the access point provides UE measurements to the smart repeater. Based on this information and the smart repeater's own RSRP measurements of the SR backhaul beam, the smart repeater determines the optimal access beam for transmissions toward that particular UE.

[0147] 10, in step 1001, a smart repeater (SR) and at least one UE may establish an initial connection to an access point (e.g., gNB) using a wide SR spatial filter (beam). The smart repeater may also inform the access point regarding the number of backhaul beams and access beams of the smart repeater.

[0148] In step 1002, the smart repeater can transmit capability information to the access point via a backhaul link between the smart repeater and the access point, the capability information including a capability instruction for performing a backhaul-access integrated spatial filter (beam) refinement procedure in the smart repeater. For example, the capability information can be transmitted in a Medium Access Control (MAC) control element (CE) in an uplink or in an RRC.

[0149] The capability information helps the access point not to schedule dedicated reference signal repetitions specifically for gNB-SR-P3, but to wait until at least one UE is available for SR / gNB-UE-P2. If a UE is not available or cannot be scheduled within a reasonable time window (e.g., half the L1 / RSRP CSI-RS period), the access point can revert to dedicated gNB-SR-P3.

[0150] In step 1003, the access point can transmit a backhaul resource configuration to the smart repeater over a backhaul link, the backhaul resource configuration indicating one or more time-frequency resources to be used for the first reference signal set. The backhaul resource configuration causes the access point to configure the smart repeater for access beam sweeping.

[0151] For example, an access point may semi-statically or periodically transmit a backhaul resource configuration to a smart repeater to indicate the time division duplex (TDD) time slot and reference signal resource structure to be used for each active reference signal of the access point.

[0152] In step 1004, the access point may configure at least one UE for reference signal beam measurements and reporting.

[0153] In step 1005, the access point may transmit a first reference signal (RS) set to the smart repeater using the same spatial filter (angular direction) but a different identifier (e.g., beam ID) to simulate a sweep. Although the access point exhibits repetition-like behavior, the repetition flag may not be set in the UE RS resource RRM configuration.

[0154] The first reference signal set may include at least one of a channel state information reference signal (CSI-RS), a primary synchronization signal (PSS), a secondary synchronization signal (SSS), or a tracking reference signal (TRS).

[0155] In step 1006, the smart repeater may amplify and transmit a second reference signal set to at least one UE via the access link using a different spatial filter, where the second reference signal set corresponds to the first reference signal set. In other words, the smart repeater may amplify and forward the received first reference signal set (i.e., the second reference signal set may be the same as the first reference signal set). When transmitting the second reference signal set via the access link, the smart repeater may amplify each reference signal in the second reference signal set by an equal amount (i.e., with the same amplification gain).

[0156] In step 1007, the smart repeater may sweep its backhaul (BH) spatial filter (backhaul beam) and measure the received power (e.g., RSRP) of each reference signal (resource) of the first reference signal set on the backhaul spatial filter to obtain a first set of measurement results indicating the received power of the first reference signal set.

[0157] In step 1008, the smart repeater can map the first reference signal set to a set of spatial filters used to transmit the second reference signal set over the access link. In other words, the smart repeater can map each reference signal of the received first reference signal set to a spatial filter (beam) of the access (AC) link.

[0158] In step 1009, the smart repeater may obtain or select a spatial filter (beam) for the backhaul link based on the first set of measurements obtained in step 1007. For example, the smart repeater may select the spatial filter with the highest measured RSRP.

[0159] In step 1010, at least one UE may measure the received power (e.g., RSRP) of a second set of reference signals received through a different spatial filter via the access link to obtain a second set of measurement results indicating the received power of the second set of reference signals.

[0160] In step 1011, at least one UE may send a report to the access point to report the second set of measurement results obtained in step 1010. In other words, the UE may report the measurement spatial filter and the corresponding measurement RSRP value (or offset to the best beam) to the access point through the uplink path amplified by the smart repeater.

[0161] In step 1012, the access point transmits access link information to the smart repeater, the access link information including a second set of measurement results indicating the received power of a second set of reference signals. This indirect reporting is required because the UE and the smart repeater do not have a direct communication link.

[0162] In step 1013, the smart repeater can compensate the second set of measurements obtained from the access link information based on the first set of measurements. In other words, based on the first set of measurements, the second set of measurements, and the applied mapping of step 1008, the smart repeater compensates for the effect of the backhaul spatial filter on the access link spatial filter.

[0163] For example, for each reference signal n received by the smart repeater through backhaul link spatial filter i and transmitted through access link spatial filter j, the access point can calculate a delta offset relative to the lowest measurement value in the first set of measurements as follows:

[0164]

number

[0165] During the ceremony,

number

number

[0166] The smart repeater can compensate the RSRP value of the second measurement set by the calculated delta offset as follows:

[0167]

number

[0168] In step 1014, based at least in part on the compensated second set of measurements and the applied mapping of step 1008, the smart repeater obtains or determines a spatial filter (beam) for communicating with at least one UE over the access link.

[0169] Thus, the smart repeater obtains at least one spatial filter pair (beam pair) for the backhaul link and the access link based at least in part on the access link information and the first set of measurement results of the first set of reference signals.

[0170] The spatial filter obtained for the access link may be the spatial filter that would have provided the highest RSRP (from an SR perspective) if the second reference signal set had been transmitted with normalized transmit power. For example, spatial filter j * is the reference signal identifier n * (According to the mapping from step 1008, the access link spatial filter j * can be obtained by determining the

[0171]

number

[0172] In step 1015, the smart repeater can communicate with at least one UE and access point via the obtained at least one spatial filter pair.

[0173] Note that some example embodiments may also be applicable to multiple UEs, in which case the entity (access point or smart repeater) determining the SR spatial filter for the access link may repeat the calculation / compensation for each UE, but the backhaul spatial filter measurements may remain unchanged for each UE.

[0174] 11 shows a flowchart according to one or more exemplary embodiments. The steps shown in FIG. 11 may be performed by a device such as or included in a (smart) repeater.

[0175] 11 , in step 1101, access link information is received from an access point via a backhaul link, the access link information including or indicating received power of one or more reference signals or an indication of a spatial filter for an access link between the (smart) repeater and at least one UE, which may also be referred to herein as user equipment, user device, or terminal device.

[0176] In step 1102, at least one spatial filter pair for the backhaul link and the access link is obtained based at least in part on the access link information.

[0177] 12 shows a flowchart according to an example embodiment. The steps shown in FIG. 12 may be performed by an apparatus such as or included in an access point (e.g., a gNB).

[0178] 12, in step 1201, access link information of a (smart) repeater is obtained, where the access link information includes or indicates the received power of one or more reference signals or an indication of a spatial filter for the access link between the (smart repeater) and at least one UE, which may also be referred to herein as user equipment, a user device, or a terminal device.

[0179] In step 1202, the access link information is transmitted to the (smart) repeater via the backhaul link.

[0180] The steps and / or blocks described above with reference to Figures 9-12 are not in absolute chronological order; some of them may be performed simultaneously or in a different order than described. Other steps and / or blocks may also be performed between or within them. For example, steps 905-910 of Figure 9 may be performed in lockstep (i.e., substantially simultaneously).

[0181] A technical advantage provided by some exemplary embodiments is that they simultaneously implement gNB-SR-P3 and SR-UE-P2 beam refinement procedures without power normalization, reducing the number of RS transmissions by avoiding suboptimal selection of an SR access beam (spatial filter for the access link). In other words, some exemplary embodiments enable SR backhaul-access joint beam refinement across one reference signal set without power normalization at smart repeaters by compensating for different SR access beam RSRP values ​​caused by unbalanced RSRPs of SR backhaul beams.

[0182] Some exemplary embodiments may conserve resources by reducing the need for two RS beam sets to one set. Additionally, some exemplary embodiments may reduce SR complexity because power normalization is not required in SR. Some exemplary embodiments may also improve SR performance by allowing the backhaul and access beams to be adjusted more frequently and with lower latency.

[0183] 13 illustrates an apparatus 1300 that may be a terminal device or a device included in a terminal device, according to an exemplary embodiment. The terminal device may also be referred to herein as a UE or user equipment. The apparatus 1300 includes a processor 1310. The processor 1310 interprets computer program instructions and processes data. The processor 1310 may include one or more programmable processors. The processor 1310 may include programmable hardware with embedded firmware, or alternatively or additionally, may include one or more application-specific integrated circuits (ASICs).

[0184] The processor 1310 is coupled to the memory 1320. The processor is configured to read and write data to and from the memory 1320. The memory 1320 may include one or more memory units. The memory units may be volatile or nonvolatile. Note that in some exemplary embodiments, there may be one or more units of nonvolatile memory and one or more units of volatile memory, or alternatively, there may be one or more units of nonvolatile memory or one or more units of volatile memory. The volatile memory may be, for example, random access memory (RAM), dynamic random access memory (DRAM), or synchronous dynamic random access memory (SDRAM). The nonvolatile memory may be, for example, read-only memory (ROM), programmable read-only memory (PROM), electrically erasable programmable read-only memory (EEPROM), flash memory, optical storage, or magnetic storage. Generally, memory may be referred to as a non-transitory computer-readable medium. The memory 1320 stores computer-readable instructions executed by the processor 1310. For example, non-volatile memory stores computer-readable instructions, and processor 1310 executes the instructions using volatile memory for temporarily storing data and / or instructions.

[0185] The computer-readable instructions may be pre-stored in memory 1320, or alternatively or additionally, they may be received by the device via an electromagnetic carrier signal and / or copied from a physical entity such as a computer program product. Execution of the computer-readable instructions causes device 1300 to perform one or more of the functions described above.

[0186] In the context of this specification, "memory" or "computer-readable media" or "computer-readable medium" may be any non-transitory medium or means that can contain, store, communicate, propagate, or transport instructions for use by or in cooperation with an instruction execution system, apparatus, or device, such as a computer.

[0187] The device 1300 may further comprise or be connected to an input unit 1330. The input unit 1330 may include one or more interfaces for receiving input. The one or more interfaces may include, for example, one or more temperature, motion and / or orientation sensors, one or more cameras, one or more accelerometers, one or more microphones, one or more buttons and / or one or more touch detection units. Furthermore, the input unit 1330 may include an interface to which external devices may be connected.

[0188] The device 1300 may also include an output unit 1340. The output unit may include or be connected to one or more displays capable of rendering visual content, such as a light-emitting diode (LED) display, a liquid crystal display (LCD) and / or a liquid crystal on silicon (LCoS) display. The output unit 1340 may further include one or more audio outputs. The one or more audio outputs may be, for example, speakers.

[0189] The device 1300 further comprises a connection unit 1350. The connection unit 1350 enables wireless connection to one or more external devices. The connection unit 1350 comprises at least one transmitter and at least one receiver, which may be integrated into the device 1300 or to which the device 1300 may be connected. The at least one transmitter comprises at least one transmitting antenna, and the at least one receiver comprises at least one receiving antenna. The connection unit 1350 may comprise an integrated circuit or a set of integrated circuits that provide the wireless communication functionality of the device 1300. Alternatively, the wireless connection may be a hardwired application-specific integrated circuit (ASIC). The connection unit 1350 may comprise one or more components, such as a power amplifier, a digital front end (DFE), an analog-to-digital converter (ADC), a digital-to-analog converter (DAC), a frequency converter, a modulator (demodulator), and / or an encoder / decoder circuit, controlled by a corresponding control unit.

[0190] It should be noted that the apparatus 1300 may further comprise various components not shown in Figure 13. The various components may be hardware and / or software components.

[0191] The apparatus 1400 of FIG. 14 illustrates an exemplary embodiment of an apparatus such as or included in a network element of a wireless communications network. A network element may also be referred to as, for example, a repeater, smart repeater, network node, RAN node, integrated access and backhaul (IAB) node, IAB donor node, NodeB, LTE evolved NodeB (eNB), gNB, base station, NR base station, 5G base station, access node, access point (AP), distributed unit (DU), central unit (CU), baseband unit (BBU), radio unit (RU), radio head, remote radio head (RRH), or transmit / receive point (TRP). The apparatus 1400 may comprise, for example, a circuit or chipset applicable to implementing some of the exemplary embodiments described. The apparatus 1400 may also be an electronic device comprising one or more electronic circuits. The device 1400 may include communication control circuitry 1410, such as at least one processor, and at least one memory 1420 containing computer program code (software) 1422, the at least one memory and the computer program code (software) 1422 being configured by the at least one processor to cause the device 1400 to perform some of the exemplary embodiments described above.

[0192] The processor is coupled to the memory 1420. The processor is configured to read and write data to and from the memory 1420. The memory 1420 may include one or more memory units. The memory units may be volatile or nonvolatile. Note that in some exemplary embodiments, there may be one or more units of nonvolatile memory and one or more units of volatile memory, or alternatively, there may be one or more units of nonvolatile memory, or alternatively, there may be one or more units of volatile memory. The volatile memory may be, for example, random access memory (RAM), dynamic random access memory (DRAM), or synchronous dynamic random access memory (SDRAM). The nonvolatile memory may be, for example, read-only memory (ROM), programmable read-only memory (PROM), electrically erasable programmable read-only memory (EEPROM), flash memory, optical storage, or magnetic storage. Generally, memory may be referred to as a non-transitory computer-readable medium. The memory 1420 stores computer-readable instructions that are executed by the processor. For example, non-volatile memory stores computer-readable instructions, and a processor executes the instructions using volatile memory for temporarily storing data and / or instructions.

[0193] The computer-readable instructions may be pre-stored in memory 1420, or alternatively or additionally, they may be received by the device via an electromagnetic carrier signal and / or copied from a physical entity such as a computer program product. Execution of the computer-readable instructions causes device 1400 to perform one or more of the functions described above.

[0194] The memory 1420 may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, flash memory, magnetic memory devices and systems, optical memory devices and systems, fixed memory and / or removable memory. The memory may include a configuration database for storing configuration data. For example, the configuration database may store a list of current neighboring cells and, in some exemplary embodiments, the frame structure used in detected neighboring cells.

[0195] The apparatus 1400 may further comprise a communication interface 1430 including hardware and / or software for implementing a communication connection according to one or more communication protocols. The communication interface 1430 comprises at least one transceiver (TRX) that may be integrated into the apparatus 1400 or to which the apparatus 1400 may be connected. The communication interface 1430 provides the apparatus with wireless communication capabilities for communicating within a cellular communication system. The communication interface may, for example, provide a radio interface to a terminal device. The apparatus 1400 may further comprise another interface to a core network and / or an access node of the cellular communication system, such as a network coordinator apparatus. The apparatus 1400 may further comprise a scheduler 1440 configured to allocate resources. The scheduler 1440 may be configured together with the communication control circuitry 1410 or may be configured separately.

[0196] The term "circuitry" as used in this application may refer to one or more or all of: a) hardware-only circuit implementations (such as implementations in only analog and / or digital circuitry); and b) (where applicable) i) combinations of analog and / or digital hardware circuitry and software / firmware; and ii) combinations of hardware circuitry and software, such as any portion of a hardware processor having software (including digital signal processors), software, and memory that cooperate to cause a device such as a mobile phone to perform various functions; and c) hardware circuits and / or processors, such as a microprocessor or portion of a microprocessor, that require software (e.g., firmware) to operate, but that may be absent when the software is not necessary for operation.

[0197] This definition of circuit applies to all uses of the term in this application, including any patent claims. As a further example, as used in this application, the term circuit also covers a hardware circuit or processor (or processors) or portion of a hardware circuit or processor, as well as its (or their) accompanying software and / or firmware-only implementations. The term circuit also covers, for example, baseband or processor integrated circuits for mobile devices, or similar integrated circuits in servers, cellular network devices, or other computing or network devices, if applicable to certain claim elements.

[0198] The techniques and methods described herein may be implemented by various means. For example, these techniques may be implemented in hardware (one or more devices), firmware (one or more devices), software (one or more modules), or a combination thereof. For a hardware implementation, the apparatus of the exemplary embodiments may be implemented in one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), graphics processing units (GPUs), processors, controllers, microcontrollers, microprocessors, other electronic units designed to perform the functions described herein, or a combination thereof. For firmware or software, implementation may be performed through modules (e.g., procedures, functions, etc.) of at least one chipset that performs the functions described herein. The software code may be stored in a memory unit and executed by the processor. The memory unit may be implemented within the processor or external to the processor. In the latter case, it may be communicatively coupled to the processor via various means, as known in the art. Additionally, as will be appreciated by those skilled in the art, the components of the systems described herein may be reconfigured and / or supplemented with additional components to facilitate, for example, the accomplishment of the various aspects described in connection therewith, and are not limited to the precise configurations depicted in the given drawings.

[0199] It will be obvious to those skilled in the art that as technology advances, the concept of the present invention can be implemented in various ways. The embodiments are not limited to the exemplary embodiments described above, but may vary within the scope of the claims. Therefore, all words and expressions should be interpreted broadly, and they are intended to illustrate, rather than limit, the exemplary embodiments.

Claims

1. 1. An apparatus for a repeater, comprising: at least one processor; and at least one transceiver, the at least one transceiver comprising: configured to receive access link information from the access point via a backhaul link, the access link information including received power of one or more reference signals or an indication of a spatial filter for the access link; The at least one processor configured to obtain at least one spatial filter pair for the backhaul link and the access link based at least in part on the access link information; The at least one transceiver receiving a first set of reference signals from the access point via the backhaul link using the same spatial filter; 11. The apparatus, further configured to transmit a second set of reference signals to at least one terminal device over the access link using a different spatial filter, the second set of reference signals corresponding to the first set of reference signals.

2. the access link information includes received power of the second reference signal set or an indication of the spatial filter for the access link; The apparatus of claim 1 , wherein the at least one spatial filter pair is obtained based at least in part on the access link information and the first set of reference signals.

3. The at least one transceiver 3. The apparatus of claim 1, further configured to amplify the second set of reference signals by an equal amount when transmitting the second set of reference signals over the access link.

4. The second reference signal set corresponding to the first reference signal set is a mapping of the first reference signal set to a set of spatial filters used to transmit the second reference signal set over the access link; The apparatus of any one of claims 1 to 2, wherein the at least one spatial filter pair is obtained based at least in part on the mapping.

5. The at least one processor obtaining a first set of measurement results indicative of received power of the first set of reference signals; obtaining a second set of measurement results from the access link information, the second set of measurement results indicating received power of the second set of reference signals; further configured to compensate the second set of measurements based on the first set of measurements; The apparatus of any one of claims 1 to 4, wherein the at least one spatial filter pair is obtained based at least in part on the compensated second set of measurements.

6. The at least one transceiver 6. The apparatus of claim 1, further configured to send a report to the access point via the backhaul link, the report indicating received power of the first set of reference signals.

7. The at least one transceiver 7. The apparatus of claim 1, further configured to receive a backhaul resource configuration via the backhaul link, the backhaul resource configuration indicating one or more time-frequency resources to be used for the first reference signal set.

8. The at least one transceiver 8. The apparatus of claim 1, further configured to transmit capability information to the access point via the backhaul link, the capability information including a capability indication for backhaul and access integrated spatial filter refinement.

9. The at least one transceiver The apparatus according to any one of claims 1 to 8, further configured to communicate with the at least one terminal device via the obtained at least one spatial filter pair.

10. 10. The apparatus of claim 1, wherein the indication of the spatial filter for the access link includes one or more spatial filters to be used across the access link, or a pair of spatial filters between the backhaul link and the access link.

11. The apparatus of any one of claims 1 to 10, wherein the one or more reference signals include at least one of a channel state information reference signal CSI-RS, a primary synchronization signal, a secondary synchronization signal, or a tracking reference signal TRS.

12. 1. An apparatus for an access point, comprising: at least one processor; and at least one transceiver, the at least one processor configured to: configured to obtain access link information of the repeater, the access link information including received power of one or more reference signals or an indication of a spatial filter for the access link; The at least one transceiver transmitting the access link information to the repeater via a backhaul link; transmitting a first set of reference signals to the repeater via the backhaul link, wherein the first set of reference signals are transmitted using the same spatial filter; receiving a first set of measurement results indicative of received power of the first set of reference signals transmitted over the backhaul link; receive a second set of measurements indicative of received power of a second set of reference signals relayed by the repeater over the access link, where the second set of reference signals corresponds to the first set of reference signals.

13. The apparatus of claim 12 , wherein the access link information is obtained based at least in part on the first set of measurements and the second set of measurements.

14. The at least one processor 14. The apparatus of claim 12 or 13, further configured to compensate the second set of measurements based on the first set of measurements.

15. The at least one transceiver 15. The apparatus of claim 12, further configured to transmit a backhaul resource configuration to the repeater via the backhaul link, the backhaul resource configuration indicating one or more time-frequency resources to be used for the first reference signal set.

16. The at least one transceiver The apparatus of any one of claims 12 to 15, further configured to receive capability information from the repeater via the backhaul link, the capability information including a capability indication for backhaul access integrated spatial filter refinement.

17. 17. The apparatus of claim 12, wherein the one or more reference signals include at least one of a channel state information reference signal (CSI-RS), a primary synchronization signal, a secondary synchronization signal, or a tracking reference signal (TRS).

18. receiving, by the repeater, access link information from the access point via a backhaul link, the access link information including received power of one or more reference signals or an indication of a spatial filter for the access link; obtaining, by the repeater, at least one spatial filter pair for the backhaul link and the access link based at least in part on the access link information; receiving, by the repeater, a first set of reference signals from the access point via the backhaul link using the same spatial filter; transmitting, by the repeater, a second set of reference signals to at least one terminal device over the access link using a different spatial filter, the second set of reference signals corresponding to the first set of reference signals; A method comprising:

19. obtaining, by the access point, access link information of the repeater, the access link information including received power of one or more reference signals or an indication of a spatial filter for the access link; transmitting, by the access point, the access link information to the repeater over a backhaul link; transmitting, by the access point, a first set of reference signals to the repeater via the backhaul link, the first set of reference signals being transmitted using the same spatial filter; receiving, by the access point, a first set of measurements indicative of received power of the first set of reference signals transmitted over the backhaul link; receiving, by the access point, a second set of measurements indicative of received power of a second set of reference signals relayed by the repeater over the access link, the second set of reference signals corresponding to the first set of reference signals; A method comprising:

20. An apparatus for a repeater, comprising at least: receiving access link information from an access point via a backhaul link, the access link information including received power of one or more reference signals or an indication of a spatial filter for the access link; obtaining at least one spatial filter pair for the backhaul link and the access link based at least in part on the access link information; receiving a first set of reference signals from the access point via the backhaul link using the same spatial filter; transmitting a second set of reference signals to at least one terminal device over the access link using a different spatial filter, the second set of reference signals corresponding to the first set of reference signals; A computer program comprising instructions for causing a computer to perform the steps of:

21. An apparatus for an access point, comprising: obtaining access link information for the repeater, the access link information including received power of one or more reference signals or an indication of a spatial filter for the access link; transmitting the access link information to the repeater via a backhaul link; transmitting a first set of reference signals to the repeater via the backhaul link, the first set of reference signals being transmitted using a same spatial filter; receiving a first set of measurement results indicative of received power of the first set of reference signals transmitted over the backhaul link; receiving a second set of measurements indicative of received power of a second set of reference signals relayed by the repeater over the access link, where the second set of reference signals corresponds to the first set of reference signals; and A computer program comprising instructions for causing a computer to perform the steps of:

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