WO2024080911A1 - Conditional sending of nr-u metrics - Google Patents

Abstract

A first radio access network, RAN, node sends, to a second RAN node (20b) neighboring the first RAN node (20a), a request for load information regarding shared spectrum transmissions that involve a third RAN node (20c) neighboring the second RAN node (20b). The second RAN node (20b) receives the request for load information and sends a further request for the load information to the third RAN node (20c). The third RAN node (20c) receives the further request from the second RAN node (20b) on behalf of the first RAN node (20a) and sends the requested load information to the first RAN node (20a) via the second RAN node (20b).

Description

CONDITIONAL SENDING OF NR-U METRICS

RELATED AFFLICTIONS

This application claims the benefit of U.S. Provisional Application No. 63/415618, filed 12 October 2022, the entire disclosure of which being hereby incorporated by reference herein.

TECHNICAL FIELD

Embodiments of the present disclosure generally relate to wireless communication networks, and particularly relates to controlling how metrics are reported between Radio Access Network (RAN) nodes that provide radio access coverage areas using a shared spectrum.

BACKGROUND

Figure 1 is a diagram schematically illustrating the overall architecture of an example Next Generation (NG) Radio Access Network (RAN) 50. The NG-RAN comprises of a set of RAN nodes 20 (gNodeBs (gNBs) in this example) connected to a Core Network (CN) 60 (a Fifth Generation Core (5GC) in this example) through an NG interface. Although not shown in Figure 1 , the NG-RAN 50 may also include of a set of NG eNodeBs (ng-eNBs). An ng-eNB may comprise an ng-eNB Control Unit (ng-eNB- CU) and one or more ng-eNB Distributed Units (ng-eNB-DUs). An ng-eNB-CU and an ng- eNB-DU is connected via a W1 interface. In general, the principles described with respect to a gNB and F1 interface may also be applied to the ng-eNB and W1 interface, if not explicitly specified otherwise.

A gNB may support Frequency Division Duplexing (FDD) mode, Time Division Duplexing (TDD) mode, or dual mode operation. gNBs can be interconnected through an Xn interface. A gNB may comprise a gNB-CU 58 and one or more gNB-DU(s) 57. A gNB- CU 58 and a gNB-DU 57 may be connected via an F1 interface. Traditionally, one gNB- DU 57 is connected to only one gNB-CU 58.

In case of network sharing with multiple cell ID broadcast, each cell identity associated with a subset of Public Land Mobile Networks (PLMNs) corresponds to a gNB- DU 57 and the gNB-CU 58 it is connected to. The corresponding gNB-DUs share the same physical layer cell resources.

For resiliency, a gNB-DU 57 may be connected to multiple gNB-CUs 58 by appropriate implementation. NG, Xn, and F1 are logical interfaces. For NG-RAN 50, the NG and Xn-C interfaces for a gNB (including a gNB-Cll 58 and gNB-DUs 57) terminate in the gNB-CU 58. For Dual Connectivity (DC) scenarios that include Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (E-UTRA) and NG (i.e., EN-DC), the S1 -U and X2-C interfaces for a gNB (including a gNB-CU 58 and gNB- DUs) terminate in the gNB-CU 58. The gNB-CU 58 and connected gNB-DUs are traditionally only visible to other gNBs and the 5GC as a gNB.

The node hosting the user plane part of New Radio (NR) Packet Data Convergence Protocol (PDCP) (e.g. gNB-CU 58, gNB-CU-UP 62, and for EN-DC, Master eNB (MeNB) or Secondary gNB (SgNB), depending on the bearer split) may perform user inactivity monitoring and may further inform its inactivity or (re)activation to the node having a control plane (C-plane) connection towards the core network 60 (e.g., over an E1 or X2 interface). The node hosting NR Radio Link Control (RLC) (e.g. a gNB-DU) may perform user inactivity monitoring and further inform its inactivity or (re)activation to the node hosting control plane, e.g., a gNB-CU 58 or gNB-CU-CP.

Uplink (UL) PDCP configuration (i.e., how the User Equipment (UE) uses the UL at the assisting node) is indicated via X2-C (for EN-DC), Xn-C (for NG-RAN) and F1-C. Radio Link Outage/Resume for downlink (DL) and/or UL is indicated via X2-U (for EN- DC), Xn-U (for NG-RAN) and F1-U.

The NG-RAN 50 is layered into a Radio Network Layer (RNL) and a Transport Network Layer (TNL). The NG-RAN architecture, i.e., the NG-RAN logical nodes and interfaces between them, is defined as part of the RNL. For each NG-RAN interface (NG, Xn, F1 ) the related TNL protocol and the functionality are specified. The TNL provides services for user plane transport, signaling transport.

In NG-Flex configuration, each NG-RAN node is connected to all Access and Mobility Management Functions (AMFs) of AMF Sets within an AMF Region supporting at least one network slice also supported by the NG-RAN node. The AMF Set and the AMF Region are defined in 3GPP TS 23.501 .

If security protection for control plane and user plane data on TNL of NG-RAN interfaces has to be supported, Network Domain Security I Internet Protocol (NDS/IP) as specified by 3GPP TS 33.501 is traditionally applied.

The traditional overall architecture for separation of the gNB-CU Control Plane (CP) 61 and gNB-CU User Plane (UP) 62 is depicted in Figure 2 and specified in TS 37.483. As shown in Figure 2, a gNB may comprise a gNB-CU-CP 61 , multiple gNB-CU- UPs 62 and multiple gNB-DUs. The gNB-CU-CP 61 is connected to the gNB-DU 57 through the F1-C interface. The gNB-CU-UP 62 is connected to the gNB-Dll 57 through the F1 -LI interface. The gNB-CU-UP 62 is connected to the gNB-CU-CP 61 through the E1 interface. One gNB-DU 57 is connected to only one gNB-CU-CP 61. One gNB-CU- UP 62 is connected to only one gNB-CU-CP 61. For resiliency, a gNB-DU 57 and/or a gNB-CU-UP 62 may be connected to multiple gNB-CU-CPs 61 by appropriate implementation.

One gNB-DU 57 can be connected to multiple gNB-CU-UPs 62 under the control of the same gNB-CU-CP 61. One gNB-CU-UP 62 can be connected to multiple DUs under the control of the same gNB-CU-CP 61 .

The connectivity between a gNB-CU-UP 62 and a gNB-DU 57 is established by the gNB-CU-CP 61 using Bearer Context Management functions.

The gNB-CU-CP 61 selects the appropriate gNB-CU-UP(s) 62 for the requested services for the UE. In case of multiple CU-UPs they belong to same security domain as defined in TS 33.210.

Data forwarding between gNB-CU-UPs 62 during intra- gNB-CU-CP 61 handover within a gNB may be supported by Xn-U.

In dual connectivity, a UE capable of multiple transmission/receptions, may be connected to more than one RAN node. The RAN nodes may be of the same Radio Access Technology (RAT) (both master node and secondary node in NR or Long Term Evolution (LTE) respectively) or different RATs, e.g., one master LTE node and one secondary NR node. In specification TS 37.340 the principles of multi-radio dual connectivity is described.

Multi-Radio Dual Connectivity (MR-DC) is a generalization of the Intra-E-UTRA Dual Connectivity (DC) in which a multiple Rx/Tx capable UE may be configured to utilize resources provided by two different nodes connected via non-ideal backhaul, one providing NR access and the other one providing either E-UTRA or NR access. One node acts as the Master Node (MN) and the other as the Secondary Node (SN). The MN and SN are connected via a network interface and at least the MN is connected to the core network 60.

The MN and/or the SN can be operated with shared spectrum channel access.

In general, the functions specified for a UE may be used for an Integrated Access Backhaul (IAB) Mobile Termination (MT) (i.e., IAB-MT) unless otherwise stated. Similar as specified for UE, the IAB-MT can access the network using either one network node or using two different nodes with EN-DC and NR-DC architectures. In EN-DC, the backhauling traffic over the E-UTRA radio interface is not supported. MR-DC may be designed based on the assumption of non-ideal backhaul between the different nodes but can also be used in case of ideal backhaul.

E-UTRAN supports MR-DC via E-UTRA-NR Dual Connectivity (EN-DC), in which a UE is connected to one eNB that acts as a MN and one en-gNB that acts as a SN. The eNB is connected to the Enhanced Packet Core (EPC) via the S1 interface and to the en- gNB via the X2 interface. The en-gNB might also be connected to the EPC via the S1-LI interface and other en-gNBs via the X2-LI interface. Figure 3 is a diagram that schematically illustrates an example of the overall EN-DC architecture.

The NG-RAN 50 may support NG-RAN E-UTRA-NR Dual Connectivity (NGEN- DC), in which a UE is connected to one ng-eNB that acts as a MN and one gNB that acts as a SN. The NG-RAN 50 may additionally or alternatively support NR-E-UTRA Dual Connectivity (NE-DC), in which a UE is connected to one gNB that acts as a MN and one ng-eNB that acts as a SN. The NG-RAN may additionally or alternatively support NR-NR Dual Connectivity (NR-DC), in which a UE is connected to one gNB that acts as a MN and another gNB that acts as a SN. In addition, NR-DC can also be used when a UE is connected to two gNB-DUs 57, one serving the MCG and the other serving the SCG, connected to the same gNB-CU 58, acting both as a MN and as a SN.

The NG-RAN 50 may support mobility load balancing. For example, traditional NG- RAN systems currently extend the previously established E-UTRAN resource status reporting procedure to support the exchange of load information between two NG-RAN nodes (i.e., intra NG-RAN operations), between an NG-RAN node and an en-eNB node (for EN-DC operation), as well as between and NG-RAN node and an E-UTRAN node (for inter-system operation).

Figures 4-6 are signaling diagrams illustrating example resource status reporting operations in NG-RAN 50. Figure 4 is a signaling diagram illustrating an example resource status reporting initiation, and successful operation in NG-RAN systems.

As illustrated in Figure 4, the source NG-RAN node (e.g., NG-RAN nodel ) may initiate a resource status reporting procedure by transmitting a Resource Status Request message to one or more potential target NG-RAN node(s) (e.g., NG-RAN node2) at any point in time. However, NG RAN systems currently support the exchange of load information on a finer granularity compared to E-UTRAN systems, including load information per Synchronization Signal Block (SSB) beam coverage area and per network slice. For example, load information that the source NG-RAN node can request the target NG-RAN node to report may comprise, for example, one or more of the following information: composite available capacity (per cell, per SSB beam coverage area), slice available capacity (per Single Network Slice Selection Assistance Information (S- NSSAI)), radio resource status utilization in downlink and/or uplink (per cell, per SSB beam coverage area), a TNL load indicator, a hardware load indicator, a number of active UEs, and/or RRC connections.

As shown in Figure 4, if the target NG-RAN node 20b can provide all or part of the information requested by the source NG-RAN node 20a, the target NG-RAN node 20b transmits a Resource Status Response message 401 to the source NG-RAN node 20a to acknowledge (in full or only in part) the successful initialization of the resource status reporting.

As shown in Figure 5, if any of the requested measurements cannot be initiated, NG-RAN node 20b traditionally sends the Resource Status Failure message to NG-RAN node 20a with an appropriate cause value.

Figure 6 is a signaling diagram illustrating an example of resource status reporting in which requested measurements are transmitted using a Resource Status Update message in E-UTRAN systems. Upon successful initialization of the resource status reporting procedure, the NG-RAN node 20b reports the results of the admitted measurements using a Resource Status Update message to NG-RAN node 20a. The admitted measurements are the measurements that were successfully initiated during the preceding Resource Status Reporting Initiation procedure.

To support mobility load balancing in split RAN architecture in NG-RAN systems, the resource status reporting procedure is presently defined over three main communication interfaces: Xn, F1 and E1. Additionally, resource status reporting is enabled also over the X2 interface to support mobility load balancing in case of EN-DC operations and inter-system load balancing (though the details of this are currently being finalized in the relevant standards).

As part of 3GPP Rel-17 normative work some load metrics have been agreed for NR-Unlicensed. A gNB can signal to a peer gNB (or a gNB-DU 57 can signal to the controlling gNB-CU 58) load metrics on Channel Occupancy Time Percentage DL and Energy Detection Threshold DL, using the defined Information Elements (lEs) illustrated in the table of Figure 7. In particular, the metric Channel Occupancy Time Percentage DL explicitly refers to NR-U Channel of the serving cell. Traditionally, a node (e.g., a gNB or an UE) is not required to perform channel access procedures when there is no need to exchange data. That is, the current 3GPP standard specifies a node, (e.g., a gNB or a UE) shall perform the channel access procedures for accessing the channel(s) on which the transmission(s) are performed. That said, the RAN1 specification does not specify whether a node needs to perform the channel access procedures when no data needs to be exchanged, which implies that the node is not required to perform (and is not prohibited from performing) the channel access procedures for such case.

Moreover, a UE can be configured to perform RSSI measurement (not tied to the data transmission), and report Received Signal Strength Indicator (RSSI) and channel occupancy to the associated gNB on the channel indicated by the ARFCN-valueNR IE included in the rmtc-Config parameter.

SUMMARY

As will be explained in greater detail below, particular embodiments of the present disclosure enable a first RAN node to control the load information for shared spectrum that a second node will report with regard to a third node that has coverage areas provided by shared spectrum that, at least partially, overlap with the second node. Such control may enable the first RAN node to receive load information for shared spectrum that only affects the second node coverage areas that the first node considers to be a mobility target for mobility of UEs served, at least in part by shared spectrum, by the first node. Alternatively, such control may enable the first RAN node to receive load information for shared spectrum only affecting the second node coverage areas that might have an impact on the first node performance, for example, by interfering with the first node coverage areas.

Embodiments of the present disclosure include a method implemented by a first Radio Access Network (RAN) node. The method comprises sending, to a second RAN node neighboring the first RAN node, a request for load information regarding shared spectrum transmissions that involve a third RAN node neighboring the second RAN node. The method further comprises receiving the requested load information from the second RAN node.

In some embodiments, the request indicates a request criterion under which the second RAN node is to send a further request for the load information to the third RAN node. In some embodiments, the request indicates a filter criterion that the third RAN node is to use to identify the load information.

In some embodiments, the request is also for further load information regarding further shared spectrum transmissions that involve the second RAN node. In some such embodiments, the request indicates a coverage area of the second RAN node to which the further load information pertains.

Additionally or alternatively, the method may further comprise combining the load information and the further load information to determine a combined metric regarding load upon the second RAN node.

Additionally or alternatively, the load information and/or the further load information may comprise a predicted metric pertaining to the shared spectrum transmissions.

Additionally or alternatively, the load information and/or the further load information may comprise a measured metric pertaining to the shared spectrum transmissions.

Additionally or alternatively, the load information and/or the further load information may be provided per cell.

Additionally or alternatively, the load information and/or the further load information may be provided per reference signal beam.

Additionally or alternatively, the load information and/or further load information may be provided per New Radio Unlicensed, NR-U, channel.

Additionally or alternatively, the load information and/or further load information may be provided per network slice.

In some embodiments, the request specifies whether the shared spectrum transmissions that involve the third RAN node are uplink transmissions to, or downlink transmissions from, the third RAN node.

In some embodiments, the first RAN node and the third RAN node are not neighbors.

In some embodiments, the load information comprises a channel occupancy time percentage.

In some embodiments, the load information comprises a number of Listen Before Talk (LBT) failures.

Other embodiments include a first RAN node. The RAN node comprises interface circuitry and processing circuitry. The processing circuitry is configured to send, via the interface circuitry and to a second RAN node neighboring the first RAN node, a request for load information regarding shared spectrum transmissions that involve a third RAN node neighboring the second RAN node. The processing circuitry is further configured to receive, via the interface circuitry, the requested load information from the second RAN node.

In some embodiments, the processing circuitry is further configured to perform any of the methods described above.

Other embodiments include a computer program comprising instructions that, when executed on processing circuitry of a first RAN node, cause the first RAN node to carry out any of the first RAN node methods described above.

Yet other embodiments include a carrier containing said computer program. The carrier is one of an electronic signal, optical signal, radio signal, or computer readable storage medium.

Embodiments of the present disclosure also include a method implemented by a second RAN node. The method comprises receiving, from a first RAN node neighboring the second RAN node, a request for load information regarding shared spectrum transmissions that involve a third RAN node neighboring the second RAN node. The method further comprises sending a further request for the load information to the third RAN node. The method further comprises receiving the requested load information from the third RAN node. The method further comprises sending the requested load information to the first RAN node.

In some embodiments, sending the further request for the load information to the third RAN node is responsive to determining that a request criterion indicated in the request has been met.

In some embodiments, the request and the further request both indicate a filter criterion that the third RAN node is to use to identify the load information.

In some embodiments, the request is also for further load information regarding further shared spectrum transmissions that involve the second RAN node, the method further comprising sending the requested further load information to the first RAN node. In some such embodiments, the request indicates a coverage area of the second RAN node to which the further load information pertains, the method further comprising determining the further load information based on the coverage area indicated by the request.

Additionally or alternatively, the load information and/or the further load information may comprise a predicted metric pertaining to the shared spectrum transmissions. Additionally or alternatively, the load information and/or the further load information may comprise a measured metric pertaining to the shared spectrum transmissions.

Additionally or alternatively, the load information and/or the further load information may be sent by the second RAN node per cell.

Additionally or alternatively, wherein the load information and/or the further load information may be sent by the second RAN node per reference signal beam.

Additionally or alternatively, the load information and/or further load information may be sent by the second RAN node per New Radio Unlicensed, NR-U, channel.

Additionally or alternatively, the load information and/or further load information may be sent by the second RAN node per network slice.

In some embodiments, the request and the further request both specify whether the shared spectrum transmissions that involve the third RAN node are uplink transmissions or downlink transmissions of the third RAN node.

In some embodiments, the first RAN node and the third RAN node are not neighbors.

In some embodiments, the load information comprises a channel occupancy time percentage.

In some embodiments, the load information comprises a number of Listen Before Talk (LBT) failures.

Other embodiments include a second RAN node. The second RAN node comprises interface circuitry and processing circuitry. The processing circuitry is configured to receive, via the interface circuitry and from a first RAN node neighboring the second RAN node, a request for load information regarding shared spectrum transmissions that involve a third RAN node neighboring the second RAN node. The processing circuitry is further configured to send a further request for the load information to the third RAN node via the interface circuitry. The processing circuitry is further configured to receive the requested load information from the third RAN node via the interface circuitry. The processing circuitry is further configured to send the requested load information to the first RAN node via the interface circuitry.

In some embodiments, the processing circuitry is further configured to perform any one of the second RAN node methods described above.

Other embodiments include a computer program comprising instructions that, when executed on processing circuitry of a second RAN node, cause the source network node to carry out any one of the second RAN node methods described above. Yet other embodiments include a carrier containing said control program. The carrier is one of an electronic signal, optical signal, radio signal, or computer readable storage medium.

Embodiments of the present disclosure also include a method implemented by a third RAN node. The method comprises receiving, from a second RAN node and on behalf of a first RAN node, a request for load information regarding shared spectrum transmissions that involve the third RAN node. The second RAN node is a neighbor of both the first RAN node and the third RAN node. The method further comprises sending the requested load information to the first RAN node via the second RAN node.

In some embodiments, the method further comprises identifying the load information based on a filter criterion comprised in the request.

In some embodiments, the request specifies whether the shared spectrum transmissions that involve the third RAN node are uplink transmissions or downlink transmissions of the third RAN node.

In some embodiments, the first RAN node and the third RAN node are not neighbors.

In some embodiments, the load information comprises a predicted metric pertaining to the shared spectrum transmissions, the method further comprising predicting the predicted metric.

In some embodiments, the load information comprises a measured metric pertaining to the shared spectrum transmissions, the method further comprising measuring the measured metric.

In some embodiments, the load information comprises a channel occupancy time percentage.

In some embodiments, the load information comprises a number of Listen Before Talk (LBT) failures.

Other embodiments include a third RAN node. The third RAN node comprises interface circuitry and processing circuitry. The processing circuitry is configured to receive, from a second RAN node on behalf of a first RAN node via the interface circuitry, a request for load information regarding shared spectrum transmissions that involve the third RAN node. The second RAN node is a neighbor of both the first RAN node and the third RAN node. The processing circuitry is further configured to send, via the interface circuitry, the requested load information to the first RAN node via the second RAN node. In some embodiments, the processing circuitry is further configured to perform any one of the third RAN node methods described above.

Other embodiments include a computer program comprising instructions that, when executed on processing circuitry of a third RAN node, cause the third RAN node to carry out any one of the third RAN node methods described above.

Yet other embodiments include a carrier containing said control program. The carrier is one of an electronic signal, optical signal, radio signal, or computer readable storage medium.

BRIEF DESCRIPTION OF THE FIGURES

Aspects of the present disclosure are illustrated by way of example and are not limited by the accompanying figures with like references indicating like elements. In general, the use of a reference numeral should be regarded as referring to the depicted subject matter according to one or more embodiments, whereas discussion of a specific instance of an illustrated element will append a letter designation thereto (e.g., discussion of a RAN node 20, generally, as opposed to discussion of particular instances of RAN nodes 20a, 20b).

Figure 1 is a diagram schematically illustrating an example NG-RAN overall architecture defined in TS 38.401 .

Figure 2 is a block diagram schematically illustrating an example an overall architecture for separation of gNB-CU-CP and gNB-CU-UP.

Figure 3 is a diagram schematically illustrating an example of an EN-DC overall architecture.

Figure 4 is a signaling diagram illustrating an example of successful resource status reporting.

Figure 5 is a signaling diagram illustrating an example of unsuccessful resource status reporting.

Figure 6 is a signaling diagram illustrating an example of successful resource status updating.

Figure 7 is a table defining elements that may be used to report load metrics.

Figure 8 is a signaling diagram illustrating and example channel occupancy time percent in uplink (UP) for four nodes.

Figure 9 is a schematic diagram illustrating example coverage areas of RAN nodes, according to one or more embodiments of the present disclosure. Figures 10A-B include a table defining elements of an example Resource Status Request message.

Figures 11 A-C include a table defining elements of an example Resource Status Update message.

Figures 12A-C include a table defining elements of another example Resource Status Request message.

Figures 13A-C include a table defining elements of an example Resource Status Update message.

Figure 14 is a flow diagram illustrating an example method implemented by a first RAN node, according to one or more embodiments of the present disclosure.

Figure 15 is a flow diagram illustrating an example method implemented by a second RAN node, according to one or more embodiments of the present disclosure.

Figure 16 is a flow diagram illustrating an example method implemented by a third RAN node, according to one or more embodiments of the present disclosure.

Figure 17 is a schematic block diagram illustrating an example RAN node, according to one or more embodiments of the present disclosure.

DETAILED DESCRIPTION

In the context of this invention, the term “load information” is used to indicate one or more types of metrics that relate to utilization of resources for shared spectrum (e.g., radio resources such as Physical Resource Block utilization, Composite Available Capacity, etc.).

In the context of this invention, the term “coverage area” is used to indicate an area served by a RAN node, such as a cell, a beam, and/or a tracking area. Each of these areas may be identified by an identifier, such as a Cell Global Identity (CGI), a Beam ID, a Tracking Area Identity (TAI). The coverage area is intended as provided by shared spectrum (e.g. for NR, provided by NR Unlicensed).

A partial overlap in coverage can refer to coverage only provided by shared spectrum, or coverage provided by both shared spectrum and licensed spectrum.

The term ‘network node’ can denote a RAN node, a gNB, an eNB, a gNB-CU 58, a gNB-CU-CP 61 , an eNB-CU, a eNB-CU-CP, a gNB-CU-UP 62, an eNB-CU-UP, a gNB- DU 57, an eNB-DU, an lAB-donor, an lAB-donor-CU, an lAB-donor-CU-CP, an IAB- donor-CU-UP, an lAB-donor-DU, a Non-Real Time RAN Intelligent Controller (Non-RT RIC), a Real-Time RAN Intelligent Controller (RT-RIC), a Core Network node (e.g., AMF, or Mobility Management Entity (MME)). Embodiments of the present disclosure generally relate to load information for shared spectrum, irrespective of whether such load metrics are measured or predicted. The load information for shared spectrum may be transferred between network nodes via direct signaling (e.g., via XnAP, or F1AP, or X2AP) or via indirect signaling between network nodes (e.g., via a core network 60 using an S1 AP or NGAP interface), either in whole or in part.

It has recently been proposed within the industry to introduce additional load metrics for NR-ll (Channel Occupancy Time percentage in DL) to be collected at a first node (Nodel ) via a second, neighboring node (Node2). The load metric (e.g., Channel Occupancy Time percentage in DL) is with respect to other nodes, e.g., Node3 and Node4, wherein Node3 and Node4 are neighboring Node2 but not Nodel . A similar proposal has been made for Channel Occupancy Time percentage in UL, where a Nodel collects, via Node2, the Channel Occupancy Time percentage in UL of Node3 and Node4. Figure 8 is a signaling diagram illustrating an example of this proposed load metric collection.

A problem with this approach is that the first RAN node 20a operating in shared spectrum cannot determine how the transmission of a third RAN node 20c can affect the transmission of the first RAN node 20a, given that the third RAN node 20c is not neighboring the first RAN node 20a, but is neighboring a second RAN node which in turn, is neighboring the first RAN node 20a. Figure 9 is a schematic diagram illustrating an example of such a scenario. In Figure 9, the coverage areas of RAN nodes 20a-c are shown, according to one or more embodiments of the present disclosure.

That is, particular metrics signaled from the third RAN node 20c to first RAN node 20a via the second RAN node 20b cannot be interpreted correctly by the first RAN node 20a. Since there is no coverage overlap between the first RAN node 20a and the third RAN node 20c, a transmission occurring in the coverage area of the third RAN node 20c (in UL or DL) may not directly impact the transmissions occurring in the coverage area of the first RAN node 20a (in UL or DL). However, such a transmission might affect transmissions in the coverage area of the second RAN node 20b. This impacts the ability to correctly aggregate load metrics (e.g., the Channel Occupancy Time percentage - in UL or DL) reported by the second RAN node 20b for the third RAN node 20c. The simple addition of load metrics pertaining to the second RAN node 20b to the load metrics pertaining to the third RAN node 20c does not provide the first RAN node 20a with the correct information about load metrics for the cells/frequencies/coverage areas the first RAN node 20a is interested in, e.g., where the first RAN node 20a may need to handover UEs for traffic offloading and where the handover decisions of the first RAN node 20a would be taken based on the overall load metrics in such coverage areas of the second RAN node 20b.

To address this problem, embodiments of the present disclosure enable the first RAN node 20a to control the load information for shared spectrum that the second node will report concerning the third node, the latter of which has coverage areas provided by shared spectrum at least partially overlapping with the second node. Such control would enable, for example, the first RAN node 20a to receive load information for shared spectrum that only affects the second node coverage areas that the first node may consider as mobility target for mobility of UEs served, at least in part by shared spectrum, by the first node. Such control may additionally or alternatively enable the first RAN node 20a to receive load information for shared spectrum that only affects the second node coverage areas that might have an impact on the first node performance, for example, by interfering with the first node coverage areas.

Particular embodiments may advantageously enable a source RAN node operating in shared spectrum to take more informed decisions concerning load balancing actions to handover/offload users from one cell operating in shared spectrum and served by the source RAN node. Particular embodiments may provide extra information concerning the load in shared spectrum caused by RAN nodes other than the load in shared spectrum measured (or predicted) in the target RAN node.

Particular embodiments may additionally or alternatively advantageously allow the first RAN node 20a to control the load information for shared spectrum that it receives concerning a third RAN node 20c that is not neighboring the first RAN node 20a. In contrast, traditional solutions leave to the second RAN node 20b the decision of which load information (e.g., concerning which coverage area provided by shared spectrum) of the third RAN node 20c is reported to the first RAN node 20a. However, these traditional approaches may result in the first RAN node 20a receiving a large amount of information that is not needed and/or useful at the first RAN node 20a, for example, because the information does not affect second RAN node 20b coverage areas provided by shared spectrum that the first RAN node 20a may consider as mobility targets.

More specifically, embodiments of the present disclosure generally relate to methods executed by a first RAN node 20a, a second RAN node 20b, and a third RAN node 20c in which the RAN nodes provide coverage in shared spectrum. The first RAN node 20a is neighboring the second RAN node 20b (for at least part of the respective coverage provided by shared spectrum) and vice versa. The second RAN node 20b is neighboring the third RAN node 20c (for at least part of the respective coverage provided by shared spectrum) and vice versa. The first RAN node 20a is not neighboring the third RAN node 20c (for any part of the respective coverage provided by shared spectrum) and vice versa.

In some embodiments, the first RAN node 20a requests from the second RAN node 20b, load information pertaining to transmissions (in Uplink and/or Downlink) in shared spectrum in the third RAN node 20c. The first RAN node 20a can optionally provide to the second RAN node 20b indications or conditions which the second node can use to determine whether and how to request to the third RAN node 20c load metrics concerning transmissions (in Uplink and/or Downlink) in shared spectrum in the third RAN node 20c that are relevant for the first RAN node 20a. The first RAN node 20a may, additionally, request from the second RAN node 20b, load information pertaining to transmissions (in Uplink and/or Downlink) in shared spectrum in the second RAN node 20b, for coverage areas that the first RAN node 20a indicates as relevant, e.g., second node's cells/beams. The second RAN node 20b requests and receives from the third RAN node 20c, load information pertaining to transmissions (in Uplink and/or Downlink) in shared spectrum in the third RAN node 20c that are relevant for the first RAN node 20a, as per conditions specified by the first RAN node 20a. The second RAN node 20b sends to the first RAN node 20a, load information pertaining to transmissions (in Uplink and/or Downlink) in shared spectrum in a third RAN node 20c that are relevant for the first RAN node 20a, as per conditions specified by the second RAN node 20b and/or as per conditions specified by the first RAN node 20a. The first RAN node 20a receives from the second RAN node 20b, load information pertaining to transmissions (in Uplink and/or Downlink) in shared spectrum in a third RAN node 20c that are relevant for the first RAN node 20a, as per conditions specified by the first RAN node 20a. The first RAN node 20a may, additionally, receive from the second RAN node 20b, load information pertaining to transmissions (in Uplink and/or Downlink) in shared spectrum in the second RAN node 20b, for coverage areas requested by the first RAN node 20a, e.g., second node's cells/beams.

In some embodiments, the first RAN node 20a sends a request to the second RAN node 20b to receive from the second RAN node 20b, load information (measured or predicted) pertaining to transmissions (in Uplink and/or Downlink) in shared spectrum occurring in one or more third RAN nodes 20c that are relevant for the first RAN node 20a. The relevance of the load information to the first RAN node 20a is determined by the second RAN node 20b based on information provided by first RAN node 20a. This information may include one or more indications, filters, criteria, and/or conditions as will be further explained below (simply referred to as “conditions” hereafter, for brevity).

In some embodiments, the second RAN node 20b uses the conditions for shared spectrum to determine whether and how to request to any or to each or to all the third RAN nodes 20c load related information (e.g., load measurements or predictions) concerning transmissions (in Uplink and/or Downlink) in shared spectrum in the third RAN nodes 20c to be forwarded to the first RAN node 20a.

Additionally, the first RAN node 20a may signal to the second RAN node 20b a request to receive from the second RAN node 20b, load information (measured or predicted) pertaining to transmissions (in Uplink and/or Downlink) in shared spectrum occurring in one or more coverage areas of the second RAN node 20b. The coverage areas of the second RAN node 20b for which load information are requested by the first RAN node 20a may be at least partially overlapping with the coverage areas of the third RAN node 20c for which the first RAN node 20a is requesting load information. In some embodiments, the first RAN node 20a may indicate to the second RAN node 20b that the coverage areas of the third RAN node 20c for which load information for shared spectrum is needed is required to have at least partially overlapping coverage with the coverage areas of the second RAN node 20b for which the first RAN node 20a requested load information (i.e., only for the portion concerning shared spectrum operation, or considering coverage provided by both shared spectrum and licensed spectrum). Additionally or alternatively, the first RAN node 20a may indicate to the second RAN node 20b that the coverage areas of the third RAN node 20c for which load information for shared spectrum is needed is required to be neighboring the coverage areas of the second RAN node 20b for which the first RAN node 20a requested load information. Additionally or alternatively, the first RAN node 20a may indicate to the second RAN node 20b that the coverage areas of the third RAN node 20c for which load information for shared spectrum is needed is required to be interfering with the coverage areas of the second RAN node 20b for which the first RAN node 20a requested load information.

In some embodiments, the second RAN node 20b, based at least in part on the conditions for shared spectrum received from the first RAN node 20a, sends a request to at least one of the third RAN nodes 20c to receive, from the at least one third RAN node 20c, load information pertaining to transmissions (in Uplink and/or Downlink) in shared spectrum in the third RAN node 20c that are relevant for the first RAN node 20a and to be later forwarded to the first RAN node 20a.

In some embodiments, at least one of the third RAN nodes 20c in the set of third RAN nodes receives, from the second RAN node 20b, a request to provide to the second RAN node 20b load information pertaining to transmissions (in Uplink and/or Downlink) in shared spectrum in the third RAN node 20c.

In some such embodiments, the third RAN node 20c does not receive explicit indications that load information to be provided to the second RAN node 20b is associated (relevant) to the first RAN node 20a, but receives instead filtering criteria (e.g., identities of cells of the second RAN node 20b) which are used by the third RAN node 20c to determine which load metrics (measurements and/or predictions) the second RAN node 20b is interested to receive.

In some embodiments, the second RAN node 20b receives from at least one of the third RAN nodes 20c, load information pertaining to transmissions (in Uplink and/or Downlink) in shared spectrum in the third RAN node 20c based at least in part on the conditions for shared spectrum previously received from the first RAN node 20a.

In some embodiments, the second RAN node 20b sends to the first RAN node 20a, load information pertaining to transmissions (in Uplink and/or Downlink) in shared spectrum in at least one the third RAN nodes 20c that is relevant for the first RAN node 20a.

In some such embodiments, the second RAN node 20b signals to the first RAN node 20a load metrics for shared spectrum concerning second RAN node 20b’s coverage areas, assuming that such metrics have been also requested by the first RAN node 20a.

Thus, according to one or more embodiments discussed herein, the first RAN node 20a receives, from the second RAN node 20b, load information pertaining to transmissions (in Uplink and/or Downlink) in shared spectrum in a third RAN node 20c that are relevant to the first RAN node 20a. In some such embodiments, the first RAN node 20a may also receive load information pertaining to transmissions (in Uplink and/or Downlink) in shared spectrum in a second RAN node 20b that are relevant for the first RAN node 20a.

In some particular embodiments, the first RAN node 20a may combine the load information for shared spectrum (measurements and/or predictions) received from the second RAN node 20b concerning the second RAN node 20b coverage areas and the third RAN node 20c coverage areas so to achieve an overall representation of the load conditions (measured and/or predicted) in the second node coverage areas of interest for the first RAN node 20a, e.g. that the first RAN node 20a may use as mobility target. In one example, the overall interference in such areas of the second RAN node 20b, determining LBT failures, may be derived from the combination of information concerning the second and the third RAN node 20c. Similarly, the channel occupancy time (in Uplink and/or in Downlink) in such areas of the second RAN node 20b, namely the time the shared channel is occupied by networks or UEs different from the first RAN node 20a and its UEs, may be derived by combining the channel occupancy time (in Uplink and/or Downlink) related to coverage areas of the third and second RAN node 20b.

As noted above, the first RAN node 20a may specify “conditions” for shared spectrum that are used to assist the second RAN node 20b in determining whether and/or how one or more load metrics for shared spectrum that are measured or predicted by the third RAN node 20c and pertain to certain measurement object(s) (e.g., a cell, an SSB beam, a frequency) of the third RAN node 20c are relevant for the first RAN node 20a. The first RAN node 20a may indicate to the second RAN node 20b one or more or a combination of the following parameters, which the second RAN node 20b will use to select the coverage areas and/or measurement objects of the third RAN node 20c, and correspondingly will request load metrics related to shared spectrum:

- Node identifier(s) (e.g. Global gNB ID, Global NG-RAN Node ID)

- PLMN Identity

- Tracking Area Code (TAC)

- Tracking Area Identity (TAI)

- RAN Area Code

- Radio Notification Area (RNA) identity(ies)

- Absolute Radio Frequency Channel Number(s) (ARFCN(s), e.g. an NR-U ARFCN)

- Radio Access Technology(ies) (RATs)

- Bandwidth Part(s) (BWPs)

- Identifiers of an Area Scope associated to the first/second/third RAN node 20a-c

- Identifiers of geographical areas associated to the first/second/third RAN node 20a-c (e.g., combination of cell-IDs, polygons and circular areas)

- Multicast Broadcast Service (MBS) Service Area

- MBS Session ID

- MBS Frequency Selection Area (FSA) Identity (ID) - UE velocity and/or UE mobility state(s)

- Radio Resource Control (RRC) states

- Identifier(s) of network slice(s)

- whether shared spectrum is used in single connectivity or multi-connectivity (between shared spectrum and licensed spectrum or with shared spectrum only)

- whether transmission in shared spectrum is only in downlink

- whether transmission in shared spectrum is only in uplink

- whether carrier aggregation is used for shared spectrum

- indications concerning the first RAN node 20a, and/or the second RAN node 20b, and/or the third RAN node 20c. For example, whether a cell pertains to a Non- Public-Network (NPN), or a certain type of NPN (Standalone NPN (SNPN) or Public Network Integrated (PNI)-NPN), whether a cell is an HSDN cell, whether a cell I RAN node is an IAB cell, whether the cell or a node support Non-Terrestrial Network (NTN)

- indications of measurement Identities (e.g., to indicate collections of measurements and/or predictions initiated or ongoing between RAN nodes)

- indications of prediction Identities (e.g., to indicate collections of predictions initiated or ongoing between RAN nodes)

- indication of measurement period

- an indication of a validity time/period

- an indication of uncertainty

- Identifiers of cells, reference signals, and/or beams of the first RAN node 20a (e.g., NG-RAN Cell Identity, NG-RAN Cell PCI, SSB area index), the second RAN node 20b, and/or the third RAN node 20c.

The cells, reference signals, and/or beams can be cells, reference signals, and/or beams of the first RAN node 20a indicated by the first RAN node 20a may be those for which at least a partial overlap in coverage provided by shared spectrum exists with cells, reference signals, and/or beams of the second RAN node 20b. When present, the second RAN node 20b may use the cell, reference signal, and/or beam identifiers to select coverage areas of the third RAN node 20c, provided by shared spectrum, that fulfils one or more of the following criteria with respect to the coverage areas of the neighboring second node:

Criterion 1 : The relevant coverage area(s) at least partially overlaps with one or more coverage areas of the second RAN node 20b for which the first RAN node 20a requested load information (only for the portion concerning shared spectrum operation, or in which coverage is provided by both shared spectrum and licensed spectrum).

Criterion 2: The relevant coverage area(s) neighbors the coverage areas of the second RAN node 20b for which the first RAN node 20a requested load information.

Criterion 3: The relevant coverage area(s) interferes with the coverage areas of the second RAN node 20b for which the first RAN node 20a requested load information.

When identifiers of cells, reference signals, and/or beams of the second RAN node 20b are indicated, those cells, reference signals, and/or beams can be those for which at least a partial overlap in coverage provided by shared spectrum exists with cells, reference signals, and/or beams of the first RAN node 20a. That is, such identifiers may indicate cells, reference signals, and/or beams of the second RAN node 20b for which the first RAN node 20a is aware of at least a partial overlap in coverage provided by shared spectrum with cells, reference signals, and/or beams of the third RAN node 20c.

In some such embodiments, the second RAN node 20b selects coverage areas provided by shared spectrum of the third RAN node 20c, according to one or more of the following criteria:

Criterion 1 : The relevant coverage area(s) provided by shared spectrum of the third RAN node 20c at least partially overlap with the coverage areas provided by shared spectrum of the second RAN node 20b identified by the identifiers signaled by the first RAN node 20a.

Criterion 2: The relevant coverage area(s) provided by shared spectrum of the third RAN node 20c neighboring the coverage areas provided by shared spectrum of the second RAN node 20b identified by the identifiers signaled by the first RAN node 20a.

Criterion 3: The relevant coverage area(s) provided by shared spectrum of the third RAN node 20c interfere with the coverage areas provided by shared spectrum of the second RAN node 20b identified by the identifiers signaled by the first RAN node 20a.

When identifiers of cells, reference signals, and/or beams of the third RAN node 20c are indicated, those cells, reference signals, and/or beams may be those for which the first RAN node 20a is aware of at least a partial overlap in coverage provided by shared spectrum with cells I reference signal beams of the second RAN node 20b.

In addition to the “conditions” described above, the first RAN node 20a may additionally or alternatively send an indication for the second RAN node 20b to initiate a request for load information concerning measured or predicted utilization of the shared spectrum for one or more third RAN nodes 20c upon receiving a request from the first RAN node 20a to obtain load information updates related to shared spectrum for the second RAN node 20b. In some such embodiments, this indication can result in an implicit or explicit stop of a preceding ongoing reporting of load metrics (measured or predicted) from the third RAN node 20c to the second RAN node 20b, and the start a new reporting of load metrics from the third RAN node 20c to the second RAN node 20b.

The first RAN node 20a may additionally or alternatively send an indication for the second RAN node 20b to request load information concerning measured or predicted load information concerning shared spectrum for one or more third RAN nodes 20c with the same reporting periodicity used in the request of the first RAN node 20a for obtaining load information related to shared spectrum for the second RAN node 20b.

In some such embodiments, the reporting periodicity used in the two requests can be one a multiple of the other (e.g., twice as much, three times, etc.).

Additionally or alternatively, this indication may result in an implicit or explicit stop of a preceding ongoing reporting of load metrics (measured or predicted) from the third RAN node 20c to the second RAN node 20b and start a new reporting of load metrics from the third RAN node 20c to the second RAN node 20b.

In view of the above, an example (at least partial) definition of a message to initiate the requested measurement sent from the first RAN node 20a to the second RAN node 20b (e.g., a Resource Status Request message) is illustrated in Figures 10A-B. In this example, the first and second RAN nodes 20a, 20b may be NG-RAN nodes.

An example (at least partial) definition of a message to report the results of the requested measurements sent from the second RAN node 20b to the first RAN node 20a (e.g., a Resource Status Update message) is illustrated in Figures 11A-C. In this example, the first and second RAN nodes 20a, 20b may be NG-RAN nodes.

Another example (at least partial) definition of a message to initiate the requested measurement sent from the first RAN node 20a to the second RAN node 20b (e.g., a Resource Status Request message) is illustrated in Figures 12A-C. In this example, the first RAN node 20a may be a gNB-CU 58 and the second RAN node 20b may be a gNB- DU 57.

Another example (at least partial) definition of a message to report the results of the requested measurements sent from the second RAN node 20b to the first RAN node 20a (e.g., a Resource Status Update message) is illustrated in Figures 13A-C. In this example, the first RAN node 20a may be a gNB-CU 58 and the second RAN node 20b may be a gNB-DU 57. In view of all of the above, Figure 14 is a flow diagram illustrating an example method 1000 implemented by a first RAN node 20a. The method 1000 comprises sending, to a second RAN node 20b neighboring the first RAN node 20a, a request for load information regarding shared spectrum transmissions that involve a third RAN node 20c neighboring the second RAN node 20b (block 1010). The method 1000 further comprises receiving the requested load information from the second RAN node 20b (block 1020).

Correspondingly, Figure 15 is a flow diagram illustrating an example method 1100 implemented by a second RAN node 20b. The method 1100 comprises receiving, from a first RAN node 20a neighboring the second RAN node 20b, a request for load information regarding shared spectrum transmissions that involve a third RAN node 20c neighboring the second RAN node 20b (block 1110). The method 1100 further comprises sending a further request for the load information to the third RAN node 20c (block 1120) and receiving the requested load information from the third RAN node 20c (block 1130). The method 1100 further comprises sending the requested load information to the first RAN node 20a (block 1140).

Figure 16 is a flow diagram illustrating an example method 1200 implemented by a third RAN node 20c. The method 1200 comprises receiving, from a second RAN node 20b and on behalf of a first RAN node 20a, a request for load information regarding shared spectrum transmissions that involve the third RAN node 20c (block 1210). The second RAN node 20b is a neighbor of both the first RAN node 20a and the third RAN node 20c. The method 1200 further comprises sending the requested load information to the first RAN node 20a via the second RAN node 20b (block 1220).

Other embodiments of the present disclosure include a RAN node 20 implemented as schematically illustrated in the example of Figure 13. The RAN node 20 may be configured to operate according to the first RAN node 20a, second RAN node 20b, or third RAN node 20c described above, depending on the embodiment. The RAN node 20 of Figure 13 comprises processing circuitry 1310, memory circuitry 1320, and interface circuitry 1330. The processing circuitry 1310 is communicatively coupled to the memory circuitry 1320 and the interface circuitry 1330, e.g., via a bus 1304. The processing circuitry 1310 may comprise one or more microprocessors, microcontrollers, hardware circuits, discrete logic circuits, hardware registers, digital signal processors (DSPs), field- programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), or a combination thereof. For example, the processing circuitry 1310 may be programmable hardware capable of executing software instructions stored, e.g., as a machine-readable computer program 1340 in the memory circuitry 1320. The memory circuitry 1320 of the various embodiments may comprise any non-transitory machine-readable media known in the art or that may be developed, whether volatile or non-volatile, including but not limited to solid state media (e.g., SRAM, DRAM, DDRAM, ROM, PROM, EPROM, flash memory, solid state drive, etc.), removable storage devices (e.g., Secure Digital (SD) card, miniSD card, microSD card, memory stick, thumb-drive, USB flash drive, ROM cartridge, Universal Media Disc), fixed drive (e.g., magnetic hard disk drive), or the like, wholly or in any combination.

The interface circuitry 1330 may be a controller hub configured to control the input and output (I/O) data paths of the RAN node 20. Such I/O data paths may include data paths for exchanging signals over a network. The interface circuitry 1330 may be implemented as a unitary physical component, or as a plurality of physical components that are contiguously or separately arranged, any of which may be communicatively coupled to any other, or may communicate with any other via the processing circuitry 1310. For example, the interface circuitry 1330 may comprise a transmitter 1332 configured to send wireless communication signals and a receiver 1334 configured to receive wireless communication signals.

According to particular embodiments, the RAN node 20 is configured to operate as a first RAN node 20a. The interface circuitry 1330 is configured to exchange signals with a second RAN node 20b neighboring the first RAN node 20a. The processing circuitry 1310 is configured to send, via the interface circuitry 1330 and to the second RAN node 20b, a request for load information regarding shared spectrum transmissions that involve a third RAN node 20c neighboring the second RAN node 20b. The processing circuitry 1310 is further configured to receive, via the interface circuitry 1330, the requested load information from the second RAN node 20b.

According to other embodiments, the RAN node 20 is configured to operate as a second RAN node 20b. The interface circuitry 1330 is configured to exchange signals with a first RAN node 20a and a third RAN node 20c. The second RAN node 20b neighbors both the first RAN node 20a and the second RAN node 20b. The processing circuitry 1310 is configured to receive, via the interface circuitry 1330 and from the first RAN node 20a, a request for load information regarding shared spectrum transmissions that involve the third RAN node 20c. The processing circuitry 1310 is further configured to send a further request for the load information to the third RAN node 20c via the interface circuitry 1330. The processing circuitry 1310 is further configured to receive the requested load information from the third RAN node 20c via the interface circuitry 1330. The processing circuitry 1310 is further configured to send the requested load information to the first RAN node 20a via the interface circuitry 1330.

According to yet other embodiments, the RAN node 20 is configured to operate as a third RAN node 20c. The interface circuitry 1330 is configured to exchange signals with a second RAN node 20b neighboring the third RAN node 20c. The processing circuitry 1310 is configured to receive, from the second RAN node 20b on behalf of a first RAN node 20a via the interface circuitry 1330, a request for load information regarding shared spectrum transmissions that involve the third RAN node 20c. The second RAN node 20b is a neighbor of the first RAN node 20a. The processing circuitry 1310 is further configured to send, via the interface circuitry 1330, the requested load information to the first RAN node 20a via the second RAN node 20b.

Still other embodiments include a control program 1340 comprising instructions that, when executed on processing circuitry 1310 of a RAN node 20, cause the RAN node 20 to carry out any of the methods 1000, 1100, 1200 described herein.

Yet other embodiments include a carrier containing the control program 1340. The carrier is one of an electronic signal, optical signal, radio signal, or computer readable storage medium.

Although the computing devices described herein (e.g., RAN nodes) may include the illustrated combination of hardware components, other embodiments may comprise computing devices with different combinations of components. It is to be understood that these computing devices may comprise any suitable combination of hardware and/or software needed to perform the tasks, features, functions, and methods disclosed herein. Determining, calculating, obtaining or similar operations described herein may be performed by processing circuitry that processes information by, for example, converting the obtained information into other information, comparing the obtained information or converted information to information stored in the network node, and/or performing one or more operations based on the obtained information or converted information, and as a result of said processing making a determination. Moreover, while components are depicted as single boxes located within a larger box, or nested within multiple boxes, in practice, the devices described herein may comprise multiple different physical components that make up a single illustrated component, and functionality may be partitioned between separate components.

Claims

CLAIMS What is claimed is:

1 . A method (1000), implemented by a first Radio Access Network, RAN, node (20a), the method comprising: sending (1010), to a second RAN node (20b) neighboring the first RAN node (20a), a request for load information regarding shared spectrum transmissions that involve a third RAN node (20c) neighboring the second RAN node (20b); and receiving (1020) the requested load information from the second RAN node (20b).

2. The method of claim 1 , wherein the request indicates a request criterion under which the second RAN node (20b) is to send a further request for the load information to the third RAN node (20c).

3. The method of any one of the previous claims, wherein the request indicates a filter criterion that the third RAN node (20c) is to use to identify the load information.

4. The method of any one of the previous claims, wherein the request is also for further load information regarding further shared spectrum transmissions that involve the second RAN node (20b).

5. The method of the previous claim, wherein the request indicates a coverage area of the second RAN node (20b) to which the further load information pertains.

6. The method of claim 4 or 5, further comprising combining the load information and the further load information to determine a combined metric regarding load upon the second RAN node (20b).

7. The method of any one of claims 4-6, wherein the load information and/or the further load information comprises a predicted metric pertaining to the shared spectrum transmissions.

8. The method of any one of claims 4-7, wherein the load information and/or the further load information comprises a measured metric pertaining to the shared spectrum transmissions.

9. The method of any one of claims 4-8, wherein the load information and/or the further load information is provided per cell.

10. The method of any one of claims 4-9, wherein the load information and/or the further load information is provided per reference signal beam.

11 . The method of any one of claims 4-10, wherein the load information and/or further load information is provided per New Radio Unlicensed, NR-U, channel.

12. The method of any one of claims 4-11 , wherein the load information and/or further load information is provided per network slice.

13. The method of any one of the previous claims, wherein the request specifies whether the shared spectrum transmissions that involve the third RAN node (20c) are uplink transmissions to, or downlink transmissions from, the third RAN node (20c).

14. The method of any one of the previous claims, wherein the first RAN node (20a) and the third RAN node (20c) are not neighbors.

15. The method of any one of the previous claims, wherein the load information comprises a channel occupancy time percentage.

16. The method of any one of the previous claims, wherein the load information comprises a number of Listen Before Talk, LBT, failures.

17. A first Radio Access Network, RAN, node (20a) comprising: interface circuitry (1330) and processing circuitry (1310), wherein the processing circuitry (1310) is configured to: send, via the interface circuitry (1330) and to a second RAN node (20b) neighboring the first RAN node (20a), a request for load information regarding shared spectrum transmissions that involve a third RAN node (20c) neighboring the second RAN node (20b); and receive, via the interface circuitry (1330), the requested load information from the second RAN node (20b).

18. The first RAN node of the previous claim, wherein the processing circuitry (1310) is further configured to perform the method according to any one of claims 2-16.

19. A computer program comprising instructions that, when executed on processing circuitry (1310) of a first RAN node (20a), cause the first RAN node (20a) to carry out the method according to any one of claims 1-16.

20. A carrier containing the computer program of the preceding claim, wherein the carrier is one of an electronic signal, optical signal, radio signal, or computer readable storage medium.

21. A method (1100), implemented by a second Radio Access Network, RAN, node (20b), the method comprising: receiving (1110), from a first RAN node (20a) neighboring the second RAN node (20b), a request for load information regarding shared spectrum transmissions that involve a third RAN node (20c) neighboring the second RAN node (20b); sending (1120) a further request for the load information to the third RAN node (20c); receiving (1130) the requested load information from the third RAN node (20c); and sending (1140) the requested load information to the first RAN node (20a).

22. The method of claim 21 , wherein sending the further request for the load information to the third RAN node (20c) is responsive to determining that a request criterion indicated in the request has been met.

23. The method of any one of claims 21 -22, wherein the request and the further request both indicate a filter criterion that the third RAN node (20c) is to use to identify the load information.

24. The method of any one of claims 21-23, wherein the request is also for further load information regarding further shared spectrum transmissions that involve the second RAN node (20b), the method further comprising sending the requested further load information to the first RAN node (20a).

25. The method of the previous claim, wherein the request indicates a coverage area of the second RAN node (20b) to which the further load information pertains, the method further comprising determining the further load information based on the coverage area indicated by the request.

26. The method of any one of claims 24-25, wherein the load information and/or the further load information comprises a predicted metric pertaining to the shared spectrum transmissions.

27. The method of any one of claims 24-26, wherein the load information and/or the further load information comprises a measured metric pertaining to the shared spectrum transmissions.

28. The method of any one of claims 24-27, wherein the load information and/or the further load information is sent by the second RAN node (20b) per cell.

29. The method of any one of claims 24-28, wherein the load information and/or the further load information is sent by the second RAN node (20b) per reference signal beam.

30. The method of any one of claims 24-29, wherein the load information and/or further load information is sent by the second RAN node (20b) per New Radio Unlicensed, NR- U, channel.

31 . The method of any one of claims 24-30, wherein the load information and/or further load information is sent by the second RAN node (20b) per network slice.

32. The method of any one of claims 21 -31 , wherein the request and the further request both specify whether the shared spectrum transmissions that involve the third RAN node (20c) are uplink transmissions to, or downlink transmissions from, the third RAN node (20c).

33. The method of any one of claims 21 -32, wherein the first RAN node (20a) and the third RAN node (20c) are not neighbors.

34. The method of any one of claims 21-33, wherein the load information comprises a predicted metric pertaining to the shared spectrum transmissions.

35. The method of any one of claims 21-34, wherein the load information comprises a measured metric pertaining to the shared spectrum transmissions.

36. The method of any one of claims 21-35, wherein the load information comprises a channel occupancy time percentage.

37. The method of any one of the claims 21 -36, wherein the load information comprises a number of Listen Before Talk, LBT, failures.

38. A second Radio Access Network, RAN, node (20b) comprising: interface circuitry (1330) and processing circuitry (1310), wherein the processing circuitry (1310) is configured to: receive, via the interface circuitry (1330) and from a first RAN node (20a) neighboring the second RAN node (20b), a request for load information regarding shared spectrum transmissions that involve a third RAN node (20c) neighboring the second RAN node (20b); send a further request for the load information to the third RAN node (20c) via the interface circuitry (1330); receive the requested load information from the third RAN node (20c) via the interface circuitry (1330); and send the requested load information to the first RAN node (20a) via the interface circuitry (1330).

39. The second RAN node of the previous claim, wherein the processing circuitry (1310) is further configured to perform the method according to any one of claims 22-37.

40. A computer program comprising instructions that, when executed on processing circuitry (1310) of a second RAN node (20b), cause the source network node to carry out the method according to any one of claims 21-37.

41 . A carrier containing the control program of the preceding claim, wherein the carrier is one of an electronic signal, optical signal, radio signal, or computer readable storage medium.

42. A method (1200), implemented by a third Radio Access Network, RAN, node (20c), the method comprising: receiving (1210), from a second RAN node (20b) and on behalf of a first RAN node (20a), a request for load information regarding shared spectrum transmissions that involve the third RAN node (20c), the second RAN node (20b) being a neighbor of both the first RAN node (20a) and the third RAN node (20c); sending (1220) the requested load information to the first RAN node (20a) via the second RAN node (20b).

43. The method of the previous claim, further comprising identifying the load information based on a filter criterion comprised in the request.

44. The method of any one of claims 42-43, wherein the request specifies whether the shared spectrum transmissions that involve the third RAN node (20c) are uplink transmissions or downlink transmissions of the third RAN node (20c).

45. The method of any one of claims 42-44, wherein the first RAN node (20a) and the third RAN node (20c) are not neighbors.

46. The method of any one of claims 42-45, wherein the load information comprises a predicted metric pertaining to the shared spectrum transmissions, the method further comprising predicting the predicted metric.

47. The method of any one of claims 42-46, wherein the load information comprises a measured metric pertaining to the shared spectrum transmissions, the method further comprising measuring the measured metric.

48. The method of any one of claims 42-47, wherein the load information comprises a channel occupancy time percentage.

49. The method of any one of claims 42-48, wherein the load information comprises a number of Listen Before Talk, LBT, failures.

50. A third Radio Access Network, RAN, node (20c) comprising: interface circuitry (1330) and processing circuitry (1310), wherein the processing circuitry (1310) is configured to: receive, from a second RAN node (20b) on behalf of a first RAN node (20a) via the interface circuitry (1330), a request for load information regarding shared spectrum transmissions that involve the third RAN node (20c), the second RAN node (20b) being a neighbor of both the first RAN node (20a) and the third RAN node (20c); send, via the interface circuitry (1330), the requested load information to the first RAN node (20a) via the second RAN node (20b).

51 . The third RAN node of the previous claim, wherein the processing circuitry (1310) is further configured to perform the method according to any one of claims 43-49.

52. A computer program comprising instructions that, when executed on processing circuitry (1310) of a third RAN node (20c), cause the third RAN node (20c) to carry out the method according to any one of claims 42-49.

53. A carrier containing the control program of the preceding claim, wherein the carrier is one of an electronic signal, optical signal, radio signal, or computer readable storage medium.