Methods for CLI mitigation and network nodes thereof

Abstract

A method for interference mitigation performed by a first network node is introduced. The first network node sends RS configurations to another node for CLI measurement and reporting. CLI measurement result is reported to the first network node, which may further include a request for CLI mitigation by the first network node.

Description

METHODS FOR CLI MITIGATION AND NETWORK NODES THEREOFThis application claims the benefit of provisional application serial number US63 / 679748, filed on Aug 6, 2024, the disclosure of which is hereby incorporated by reference in its entirety.TECHNICAL FIELD

[0001] The non-limiting and exemplary embodiments of the present disclosure generally relate to the technical field of telecommunications, and specifically to methods and apparatuses for cross-link interference mitigation.BACKGROUND

[0002] The Third Generation Partnership Project (3GPP) New Radio (NR) standard (https: / / www.3gpp.org / at ftp / Specs / archive / 38_series / 38.300 / 38300-h50.zip) is being designed to provide service for multiple use cases such as enhanced mobile broadband (eMBB), ultra-reliable and low latency communication (URLLC), and machine type communication (MTC). Each of these services has different technical requirements. For example, the general requirement for eMBB is high data rate with moderate latency and moderate coverage, while URLLC service requires a low latency and high reliability transmission but perhaps for moderate data rates.

[0003] An NR slot consists of several orthogonal frequency division multiplexing (OFDM) symbols, according to current agreements either 7 or 14 symbols (OFDM subcarrier spacing < 60 kHz) and 14 symbols (OFDM subcarrier spacing > 60 kHz).

[0004] Figure 1 illustrates a NR slot with 14 OFDM symbols. In Figure 1, Tsand Tsymbdenote the slot and OFDM symbol duration, respectively.

[0005] NR supports different types of duplex communication modes. To support the many types of targeted use cases with varying requirements, different duplex communication modes are discussed in 3GPP standardization. Moreover, a same device may be capable of operating using different duplex modes, e.g., to achieve different overall communication performance based on its needs.

[0006] Transmission and reception from a wireless communication device, e.g., a base station or a user equipment (UE) in a cellular system, can be multiplexed in the frequency domain or in the time domain (or combinations thereof). The most relevant duplex modes are discussed below.

[0007] For frequency division duplex (FDD), as illustrated to the top left in Figure 2(a), transmission (TX) and reception (RX) take place in different, sufficiently separated carriers. Thus, FDD requires paired spectrum. For FDD operation, there are two carrier frequencies, one for uplink (UL) transmission and one for downlink (DL) transmission. At least with respect to the UE in a cellular communication system, FDD can be either full duplex (FD-FDD) or half duplex (HD- FDD). For FD-FDD, a UE can transmit and receive simultaneously, while in HD-FDD operation,the UE cannot transmit and receive simultaneously (the base station is still capable of simultaneous RX / TX though, e.g. receiving from one UE while simultaneously transmitting to another UE). In Long Term Evolution (LTE), a HD-FDD terminal is monitoring / receiving in the DL except when explicitly being instructed to transmit in a certain subframe.

[0008] Figure 2 illustrates different types of duplex communication modes, (a) FDD, (b) time division duplex (TDD), (c) sub-band full duplex (SBFD), and (d) in-band dull duplex (IBFD). For time division duplex (TDD), as illustrated to the top right in Figure 2(b), TX and RX take place within the same carrier in different, non-overlapping time slots. Thus, TDD can operate in unpaired spectrum. For TDD operation, there is only a single carrier frequency and UL and DL transmissions are always separated in time also on a cell basis. As the same carrier frequency is used for UL and DL transmission, both the base station and the UEs need to switch from TX to RX and vice versa.

[0009] Figure 3 illustrates a comparison of TDD operations, a) Static TDD in channel 1 and 2, b) Static TDD in channel 2 and Dynamic TDD in channel 1. An essential aspect of any TDD system is to provide the possibility for a sufficiently large guard time where neither DL nor UL transmissions occur. This is required to avoid interference between UL and DL transmissions. For NR, the guard time is provided by special slots, which are split into three parts: symbols for DL, a guard period (GP), and symbols for UL. The remaining slots are either allocated to UL or DL transmission. The only interference existing in this configuration is among transmissions happening on the same link, inside the same channel, and from an adjacent channel, if synchronization is also assumed among different operators. This is shown in Figure 3(a), where the two networks deployed in channels 1 and 2 are synchronized and will suffer only from in- channel and adjacent channel interference from the same link.

[0010] Figure 4 illustrates TDD operation options and interference cases. For Static TDD, interference links are further described in Figure 4(a). This option is, e.g., used by operators in Europe and recommended in regulations, and requires entire carrier bandwidth or all carriers in the same frequency band to be using the same DL transmission or UL reception directions.

[0011] Dynamic TDD describes a mode of operation in which a network adapts the DL / UL subframe pattern according to traffic conditions. This causes interference between different links (uplink and downlink), and it is referred to as cross link interference (CLI), BS-to-BS and UE-to- UE, as it is shown in Figure 4(b). CLI interference happens inside the same operator and interoperators. Figure 3(b) provides an example. Specifically, the deployment on channel 1 requires additional UL slots to serve UL traffic, and to do that the TDD patterns of BS1 and BS2 are adjusted to increase UL ratio. Due to that, the deployment will suffer, inside the same network, from BS-to-BS and UE-to-UE interference in slots 2 and 3. In addition, the patterns used in channel1 are unsynchronized with respect to the static TDD pattern used in channel 2. Due to that, the deployment in channel 1 will suffer from BS-to-BS and UE-to-UE interference from the adjacent channel, in slots 2, 3 and 4. On channel 2 instead, the deployment will suffer from UE-to-UE interference from the adjacent channel in slots 2, 3 and 4, but only from same link interference inside channel 2.

[0012] Sub-Band Full Duplex (SBFD), as illustrated to the bottom left in Figure 2, is being studied in 3GPP Release 18 as a part of the 5G- Advanced standardization (3GPP Technical Report TR 38.858 Study on evolution of NR duplex operation (Release 18), v 2.0, 3rd Generation Partnership Project Std., 2023). For SBFD operation, aportion of a wide bandwidth carrier, termed sub-band, may be used for a different communication direction than that of the rest of the carrier. Correspondingly, different non-overlapping sub-bands are used for DL and UL. This is unlike the conventional TDD operation wherein the entire bandwidth of the carrier is always used either for DL or UL.

[0013] SBFD operation can also be performed across different carriers within the same frequency band, wherein one or more carriers within a frequency band may be used for a different communication direction than that of the other carriers, which is again unlike conventional TDD operation wherein all carriers within a frequency band are always used for the same communication direction. In the 3GPP Release 18 study, the scope has been limited such that during SBFD communication, only BSs transmit DL and receive UL simultaneously using corresponding non-overlapping sub-bands. An individual UE is scheduled in only one direction (DL or UL) at a time, following conventional HD TDD operation.

[0014] However, for future 3GPP releases, SBFD operation at UEs wherein a UE transmits UL and receives DL simultaneously using corresponding non-overlapping sub-bands is also being discussed as a potential study topic. Interference links affecting a SBFD Rel. 18 deployments are shown in Figure 4.

[0015] Single frequency full duplex (SFFD) or in-band full duplex (IBFD), as illustrated to the bottom right in Figure 2, has also been proposed to be studied in 3GPP standardization. It was discussed but excluded from the scope of Release 18, and it is now again being discussed during scoping discussions for future releases. For SFFD operation, the entire bandwidth of the same carrier in a single carrier system or all carriers in a multi-carrier system can be simultaneously used for DL and UL operations. In other words, the same time and frequency resources can be used for both TX and RX at the same device. Similar to SBFD operation, SFFD operation is also being discussed for both BSs and UEs.

[0016] As shown in Figure 4, BS-BS CLI or gNB-gNB CLI plays a significant role in the functionality of SBFD or dynamic TDD. Many BS-BS CLI mitigation schemes were studied inTR 38.858 and each method requiring some exchange of information between gNBs. However, the details of the information were not studied.

[0017] It is worthy to note that the exchange of information is among gNBs of the same operator, and most methods described herein focus on the same.

[0018] The following is a table of all the schemes for gNB-gNB CLI mitigation handling inTR 38.858. All the schemes proposed for SBFD were also applicable to dynamic TDD and flexible TDD network deployments. Additionally, there are specific mechanisms that have been exclusively discussed for enhancing CLI mitigation in dynamic / flexible TDD deployments.Table 1: gNB-gNB CLI mitigation schemes for SBFD and dynamic / flexible TDD in TR 38.858

[0019] There currently exist certain challenges. For example, in recent working group discussions on how to solve inter-gNB cross link interference, a number of options were explored concerning the communication between radio access network (RAN) nodes to achieve coordinated actions for reduction of CLI.

[0020] However, in the previous discussions some aspects of actions coordination between gNBs were not addressed. Such aspects are important as lack of solutions in these areas lead to sub-optimal performance. SUMMARY

[0021] This summary provides a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

[0022] The need for solve inter-gNB cross link interference has been realized and several optional actions have been brought up. However, coordination between gNBs were not addressed. Certain aspects of the disclosure and their embodiments may provide solutions to these or other challenges. In a first aspect of the present disclosure, a method performed at a first gNB is provided. The first gNB as an aggressor RAN node provides a list of reference signal (RS) configurations to a victim RAN node for which the latter can measure CLI on the reference signals and report to the aggressor node along with a request for CLI mitigation.

[0023] In such way the two adjacent nodes can communicate with each other and coordinate with channel quality for both. In addition, the second gNB may become an aggressor node to the link which the first gNB is involved. Thus one or more RS configurations can also be sent to the first node as a mirrored operation. Coordination could be strengthened among several gNBs to provide balanced qualities to multiple wireless end users.

[0024] According to some embodiments, the reference signal can be CSI-RS and the one or more configurations include non-zero power-CSI-RS-ResourceSet. In another example, the reference signal can be SSB, or both types of reference signal can be used for CLI detection.

[0025] According to some embodiments, CLI measurement result can be sent to the aggressor RAN node only when high CLI level is detected / determined. It is to ensure that a victim RAN node does not send frequent and repeated requests for CLI mitigation to the aggressor RAN node. Indeed, such frequent requests may increase signaling load and impact other signalling procedures, e.g., by delaying them.

[0026] According to some embodiments, the number of RS configurations are limited to a threshold number which is less than the total amount of RS configurations / resources of the first gNB. it can help to minimize the amount of CLI mitigation actions an aggressor RAN node would have to take if many CLI mitigation requests are sent from a victim RAN node to an aggressor RAN node. The problem behind is that the aggressor RAN node would have to take all the reference signals in consideration and apply CLI mitigation actions for each of such reference signals. These embodiments are to reduce the indication of the resources where the reference signals are transmitted when interference is detected over such resources. If all resources are indicated to the victim RAN node, although it is true that such approach would eliminate a great amount of cross link interference, it is also true that this approach may imply a drop of efficiencyat the aggressor node. Then, it might result in that the benefits of reduced interference are overweighted by the negative impact of efficiency drops.

[0027] In a second aspect of the present disclosure, a method performed at a second gNB is provided. The second gNB as a victim RAN node receives a list of RS configurations to an aggressor RAN node for which the former can measure CLI on the reference signals and report to the aggressor node along with a request for CLI mitigation. Certain embodiments and technical benefit have been discussed in the embodiments of the first gNB which are omitted here for simplicity.

[0028] In a third aspect of the present disclosure, an apparatus of a network node is provided which facilitate the embodiments of those methods performed by the first and / or second network nodes.BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The above and other aspects, features, and benefits of various embodiments of the present disclosure will become more fully apparent, by way of example, from the following detailed description with reference to the accompanying drawings, in which reference numerals or letters are used to designate like or equivalent elements. The drawings are illustrated for facilitating better understanding of the embodiments of the disclosure and not necessarily drawn to scale, in which:

[0030] Figure 1 illustrates an example of an NR slot with 14 OFDM symbols in the current cellular NR system;

[0031] Figure 2 illustrates several types of duplex communication modes in the current cellular NR system;

[0032] Figure 3 provides a comparison of two types of TDD operations in the current cellular system;

[0033] Figure 4 illustrates several interference cases under different types of TDD operations in the current cellular system;

[0034] Figure 5 shows a signalling chart between to base stations according to some embodiments of the present disclosure;

[0035] Figure 6 shows a structure of a communication system including user equipments and network nodes as an example to perform the methods according to the embodiments of the present disclosure;

[0036] Figure 7 shows a structure of a network node as an example to perform the methods according to the embodiments of the present disclosure.DETAILED DESCRIPTION

[0037] Some of the embodiments contemplated herein will now be described more fully with reference to the accompanying drawings. Embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art.

[0038] As used herein, the main scenario of non-split RAN architecture and of a network made of non-split RAN nodes, e.g. gNBs, is taken as example. Such example should be considered non limiting. Namely, the embodiments and examples described herein may equivalently apply if the RAN node identified as a gNB is substituted by a gNB distributed unit (gNB-DU), an eNB, an eNB-DU or where the RAN is formed by a mixture of all such nodes. They can also apply if gNB- DU or eNB-DU is split into two nodes connected via a fronthaul interface (e.g., lower layer split in open radio access network (O-RAN)) consisting of some functions executed in the gNB / eNB- DU and other functions executed in a radio unit (RU). Therefore, where the disclosure mentions “gNB” it should be understood that it could be mentioned a gNB-DU, an eNB, an eNB-DU, RU, or any other RAN node capable of transmitting and receiving over radio access resources and generating cross node interference.

[0039] The term radio access technology (RAT), may refer to any RAT such as, for example, Universal Terrestrial Radio Access Network (UTRA), Evolved Universal Terrestrial Radio Access Network (E-UTRA), narrow band internet of things (NB-IoT), WiFi, Bluetooth, next generation RAT, NR, 4G, 5G, etc. Any of the equipment denoted by the terms node, network node or radio network node may be capable of supporting a single or multiple RATs.

[0040] The term signal or radio signal used herein can be any physical signal or physical channel. Examples of downlink (DL) physical signals are reference signal (RS) such as Primary Synchronization Signal (PSS), Secondary Synchronization Signal (SSS), Channel State Information-Reference Signal (CSI-RS), Demodulation Reference Signal (DMRS) signals in SS / PBCH block (SSB), discovery reference signal (DRS), Cell Specific Reference Signal (CRS), Positioning Reference Signal (PRS), etc. RS may be periodic. For example, RS occasions carrying one or more RSs may occur with certain periodicity (e.g., 20 ms, 40 ms, etc.). The RS may also be aperiodic.

[0041] The term time resource used herein may correspond to any type of physical resource or radio resource expressed in terms of length of time. Examples of time resources are symbol, time slot, subframe, radio frame, transmission time interval (TTI), interleaving time, slot, sub-slot, mini-slot, system frame number (SFN) cycle, hyper-SFN (H-SFN) cycle, etc. The term frequency resource used herein may correspond to any type of physical resource or radio resource expressed in terms of frequency granularity. Examples of frequency resource are channel bandwidth, subband, subcarrier, Resource block, Resource Element, etc.

[0042] In the descriptions of some embodiments, it is assumed that SBFD configuration is enabled in the RAN nodes involved.

[0043] Particular embodiments comprise the following steps. Step 1: signalling of configuration information needed to trigger CLI mitigation procedures.

[0044] A first RAN node signals to a second RAN node a set of reference signals configurations for the purpose of getting the second RAN node to measure on the resources configured for such RSs and determine if high CLI occurs. As an example, the first RAN node may signal to the second RAN node the non-zero power channel state information reference signal (NZP CSI-RS) configuration descriptions contained in the RRC NZP-CSI-RS-Resource information element (IE), NZP-CSI-RS-ResourcelD IE, NZP-CSI-RS-ResourceSet IE. Signalling of this information may occur by sending the Radio Resource Control (RRC) IES mentioned above, e.g., encoded as OCTET STRING within the application protocol message conveying them, or by signalling the content of such RRC IEs as explicit application protocol IEs within the application protocol of relevance.

[0045] In some embodiments, the first RAN node may signal to the second RAN node a limited number of RS configurations, e.g., a limited number of CSI RS configurations, where such limit may be smaller than the number of RS configurations used by the first RAN node for CLI mitigation purposes (as well as, potentially, for other purposes). Restricting the number of RS configurations the first RAN node may signal to the second RAN node limits the amount of measurements and eventually CLI mitigation actions the first RAN node may have to take if the second RAN node detects high CLI when measuring any of the RSs corresponding to the received configurations.

[0046] In a variation of these embodiments, the first RAN node signals multiple CSI-RS configurations, and a first logical grouping of CSI-RS configurations is intended for CLI measurement purposes, and a second logical grouping of CSI-RS configurations is intended for purposes other than CLI measurement. For each CSI-RS configuration, a corresponding flag is indicated, where the flag indicates to which logical grouping a CSI-RS belongs, and thus indicates whether the second node should use the CSI-RS resource for the purposes of CLI measurement.

[0047] In another variant of these embodiments, the first RAN node signals multiple synchronization signal (SS) / physical broadcast channel (PBCH) block (SSB) configurations, and a first logical grouping of SS / PBCH block configurations is intended for CLI measurement purposes and a second logical grouping of SS / PBCH block (SSB) configurations is intended for purposes other than CLI measurement, for example for mobility measurements. For each SS / PBCH (SSB) configuration, a corresponding flag is indicated, where the flag indicates to which logical grouping the SS / PBCH (SSB) configuration belongs, and thus indicates whether the secondnode should use the SS / PBCH block resource for the purposes of CLI measurement. Alternatively, only so-called non-cell-defining SS / PBCH blocks (NCD-SSB) are used for CLI measurements. A sufficient condition for an SS / PBCH block to be an NCD-SSB is that it is not located on the synchronization raster, i.e., if it is not identifiable with a global synchronization channel number (GSCN) value.

[0048] According to some embodiments, the first RAN node signals to the second RAN node sets of RS configurations, e.g., sets of CSI-RS configurations, grouping them together so that the coverage area for all the RS configuration grouped together is the same. The first RAN node may group the RS configurations according to how such RSs are transmitted. Namely the RSs corresponding to the RS configuration grouped together are signalled as part of the same beam. The second RAN node receiving such groups of RSs may therefore decide to measure signals corresponding to only one RS configuration to determine whether CLI is experienced in the beam coverage area corresponding to the group of RS.

[0049] In some embodiments, each group of RS configurations may include a single RS configuration. Namely, one RS configuration per beam is provided from the first to the second RAN node.

[0050] In some embodiments, the first RAN node may signal to the second RAN node different RS configurations grouped together. The second RAN node is required to measure the RSs corresponding to at least one RS configuration per group. This enables the second RAN node to determine if CLI is strong on the beam where the RS is transmitted. Alternatively, it enables the second RAN node to apply a different set of receive spatial filter weights (receive beamforming weights) to each RS configuration in the group to determine the relative CLI levels corresponding to different combinations of CSI-RS configuration and receive beamforming weights to determine at least one “beam pair” that has strong CLI.

[0051] To limit the requirements on CLI mitigation that a victim RAN node may pose on an aggressor RAN node, the first RAN node may also signal to the second RAN node the maximum number of RSs for which CLI mitigation actions may be taken, e.g. nulling of transmission on specific resources. In one non-limiting example, a CSI-RS may correspond to a beam. For example: if the first RAN node signals in total 15 CSI RS configurations to the second RAN node, where each of these CSI RS configuration may belong to a different RS group, the first RAN node may signal to the second RAN node that CLI mitigation can be carried out on a maximum of 2 CSI RS configurations. This helps the second RAN node to prioritise the CSI-RS configurations on which CLI mitigation is the most needed and signal them to the first RAN node, as well it helps the first (aggressor) RAN node to avoid demands for CLI mitigation on a large number of CSI-RS configurations, which could considerably reduce the first RAN node performance and efficiency.

[0052] In a variation of these embodiments, the first RAN node may signal a CLI threshold below which the second RAN node shall ignore the CLI measurement on a particular CSI-RS configuration. This enables a reduction in the CLI mitigation requests signalled to the first RAN node.

[0053] According to some embodiments, the first and second RAN nodes, when exchanging details about the configuration of the RSs for which to check for CLI, also exchange information concerning the time during which each node will take CLI mitigation actions if a request for CLI mitigation is received. As an example, if a RAN node decides to null transmissions for specific radio resources as a consequence of receiving a CLI mitigation request, the RAN node will apply such nulling for a specific amount of time. Such amount of time may have been previously communicated to the peer (victim) RAN node or it might have been configured at both peer nodes.

[0054] The first RAN node may also signal to the second RAN node the amount of time the first RAN node will apply CLI mitigation (e.g., to null resources on the interfered beams) once the second RAN node signals to the first RAN node an indication of which RS / beam is interfered. This helps the second RAN node to check the impact of the CLI mitigation (e.g., nulling) applied by the first RAN node, i.e. if during this time no CLI mitigation is detected by the second RAN node, the second RAN node may deduce that, e.g., CLI is caused by some other RAN node or factor and stop sending CLI mitigation requests to the first RAN node. Such CLI mitigation time window may also be directly configured by the operations, administration, and maintenance (0AM) system at the RAN nodes participating in CLI mitigation.

[0055] Step 2: Signalling of CLI mitigation request and possible CLI mitigation actions. At reception of the information from the first RAN node, and if detecting strong CLI when measuring on the RSs corresponding to the received RS configurations, the second RAN node signals to the first RAN node a CLI mitigation request.

[0056] As part of this request for CLI mitigation, the second RAN node may report to the firstRAN node one or more of the following:• an indication of the RS configurations for which high CLI was detected, for a number of RS configurations that is limited to the maximum number indicated by the first RAN node, if that was indicated.• an indication of one RS configuration per RS configuration group, assuming that for such RS configuration the second RAN node measured high CLI levels and assuming that the RS configuration received by the second RAN node were grouped.• an indication of another RS signal configuration for an RS signalled by the second RAN node. The first RAN node may use the received RS configuration from the second RAN node to perform further channel estimation and to optimise CLI mitigation actions.

[0057] At reception of the CLI mitigation request from the second RAN node, it is up to the first RAN node implementation which CLI mitigation action to take.

[0058] If the first RAN node applies CLI mitigation, and if a CLI mitigation time was previously indicated to the second RAN node, the first RAN node will apply CLI mitigation actions such as nulling of transmission on resources for a specific transmission beam, for the time indicated to the second RAN node. After the expiration of such time window, the first RAN node will go back to normal operation, namely the first RAN node is not required to apply any action to mitigate CLI on the resources where high CLI was detected.

[0059] In some embodiments, After the second node receives the RS configurations and the time for which CLI mitigation actions will be applied by the first node and has measured one or more of such RSs and it has determined that strong CLI is detected, the second node issues a request towards the first node for CLI mitigation. However, the second RAN node might have determined from previous requests for CLI mitigations and actions taken by the first RAN node, that CLI mitigation actions such as nulling of signal transmissions on certain time frequency resources need to be carried out for a time that is longer than what the first RAN node has declared. The second RAN node may therefore request a CLI mitigation action for n times the time window declared by the first RAN node as the CLI mitigation time window. This avoids having multiple repeated requests for CLI mitigation requests.

[0060] In some embodiments, if the second RAN node determines that measurements taken for one or more RS configurations reveal a persistent CLI on a given set of resources, and to avoid repeated and frequent requests for CLI mitigation from the second RAN node to the first RAN node, the second RAN node may signal to the first RAN node (e.g., as part of the CLI mitigation request message) a number of CLI mitigation periods for which CLI mitigation actions should be applied, namely an amount of time expressed in (CLI mitigation time as declared by the first RAN node) * n, during which the second RAN node would like the first RAN node to mitigate interference. In a variation of these embodiments, the amount of time indicated by the second RAN node is in the form of an indicator to one element of a list of CLI mitigation times declared by the first RAN node.

[0061] In some embodiments, the second RAN node includes one or more received signal strength indicator(s). The received signal indicator can for example be a reference signal received power (CSI-RSRP or SS-RSRP) or a signal-to-interference-and-noise ratio (CSI-SINR or SS- SINR). In one variant the received signal strength indicator is included only for the strongest RS configuration. In another variant, the received signal strength indicator is included for all included RS configurations, limited by the maximum number indicated by the first RAN node, if indicated.

[0062] In some embodiments, the second RAN node may include, together with a CLI mitigation request, more detailed RS configuration based on the RSs used for CLI estimation in Step 1. The new RS configuration may be used by the first RAN node to estimate the channel between the two gNBs and take CLI mitigation actions. In one variant, the new RS configuration covers or is based on multiple RSs resources from Step 1 in frequency domain. In another variant, the new RS configuration covers or is based on multiple RSs’ resources in spatial domain.

[0063] In some embodiments, the first node receiving the CLI mitigation request with all the associated information will take the request into account and the first node will decide whether to fulfil the request in part (e.g., for an amount of time that is reduced in comparison to the one requested) or in full or whether not to fulfil the request.

[0064] Figure 5 illustrates a generalisation of the message sequence between the first and second RAN nodes. The first RAN node signals to the second RAN node with configuration information about reference signals, so that CLI measurement would be taken by the second RAN node and CLI mitigation procedures would be triggered later on (when CLI measurement result is reported to the first RAN node). Resources of the reference signals are indicated in the respective configurations.

[0065] And then, reference signals, such as CSI-RS, or SSB, are received by the second RAN node according to the configurations and measurement is taken on the received signals. There could be an optional step for the second RAN node to determine whether or not to report the CLI measurement results. For example, once the value of CLI is higher than a threshold, the report is triggered. Optionally, the report can include only an indication to a strongest RS beam received by the second RAN node, or strength indicators of all received RS beams for CLI measurement.

[0066] When transmitting the CLI measurement results, which may also include channel estimation by the second RAN node, to the first RAN node, the report can optionally further include a CLI mitigation request. While whether and how to perform CLI mitigation would be decided by the first RAN node, maybe an overall consideration being taken. Optionally, the second RAN node can transmit its own RS configuration, similar to the first step performed by the first RAN node in this figure, so that the first RAN node can also perform CLI measurement between those two nodes.

[0067] Certain embodiments may provide one or more of the following technical advantages. For example, particular embodiments minimize the actions an aggressor RAN node needs to take to avoid CLI problems towards a different RAN node. In particular, the aggressor RAN may minimize the number of RS configurations for which measurements need to be taken, reducing them potentially to one RS configuration per group of RS configurations, where a group of RSconfigurations shares the characteristic of being signalled on the same coverage area, i.e., on the same beam.

[0068] Another advantage of particular embodiments reduction of the frequency with which CLI mitigation requests are signalled from the second RAN node to the first RAN node. This facilitates a reduction of the signalling load and a more efficient handling of CLI mitigation requests.

[0069] Figure 6 shows an example of a communication system QQ100 in accordance with some embodiments.

[0070] In the example, the communication system QQ100 includes a telecommunication network QQ102 that includes an access network QQ104, such as a radio access network (RAN), and a core network QQ106, which includes one or more core network nodes QQ108. The access network QQ104 includes one or more access network nodes, such as network nodes QQllOa and QQl lOb (one or more of which may be generally referred to as network nodes QQ110), or any other similar 3rdGeneration Partnership Project (3GPP) access nodes or non-3GPP access points. Moreover, as will be appreciated by those of skill in the art, a network node is not necessarily limited to an implementation in which a radio portion and a baseband portion are supplied and integrated by a single vendor. Thus, it will be understood that network nodes include disaggregated implementations or portions thereof. For example, in some embodiments, the telecommunication network QQ102 includes one or more Open-RAN (ORAN) network nodes. An ORAN network node is a node in the telecommunication network QQ102 that supports an ORAN specification (e.g., a specification published by the O-RAN Alliance, or any similar organization) and may operate alone or together with other nodes to implement one or more functionalities of any node in the telecommunication network QQ102, including one or more network nodes QQ110 and / or core network nodes QQ108.

[0071] Examples of an ORAN network node include an open radio unit (O-RU), an open distributed unit (O-DU), an open central unit (O-CU), including an O-CU control plane (O-CU- CP) or an O-CU user plane (O-CU-UP), a RAN intelligent controller (near-real time or non-real time) hosting software or software plug-ins, such as a near-real time control application (e.g., xApp) or anon-real time control application (e.g., rApp), or any combination thereof (the adjective “open” designating support of an ORAN specification). The network node may support a specification by, for example, supporting an interface defined by the ORAN specification, such as an Al, Fl, Wl, El, E2, X2, Xn interface, an open fronthaul user plane interface, or an open fronthaul management plane interface. Moreover, an ORAN access node may be a logical node in a physical node. Furthermore, an ORAN network node may be implemented in a virtualization environment (described further below) in which one or more network functions are virtualized.For example, the virtualization environment may include an O-Cloud computing platform orchestrated by a Service Management and Orchestration Framework via an 0-2 interface defined by the 0-RAN Alliance or comparable technologies. The network nodes QQ110 facilitate direct or indirect connection of user equipment (UE), such as by connecting UEs QQ112a, QQ112b, QQ112c, and QQ112d (one or more of which may be generally referred to as UEs QQ112) to the core network QQ106 over one or more wireless connections.

[0072] In some embodiments, the telecommunication network QQ102 includes a nonterrestrial network, NTN. Unless otherwise described herein, embodiments applicable for NTN may be implanted according to the following clauses. An NTN is telecommunication network where the radio access payload is conveyed via satellite to a ground station. E-UTRAN supports radio access over non-terrestrial networks for BL UEs, UEs in enhanced coverage and NB-IoT UEs. Support for non-terrestrial networks encompasses platforms that provide radio access through Geosynchronous orbits (GSO), Non-Geosynchronous Orbit (NGSO), which includes Low-Earth Orbit (LEO) and Medium Earth Orbit (MEO) or High Altitude Platform Systems (HAPS). Another example of a Non-Terrestrial Network (NTN) provides non-terrestrial NR access to the UE by means of an NTN payload and an NTN Gateway, a service link between the NTN payload and a UE, and a feeder link between the NTN Gateway and the NTN payload exists. An access network QQ104 may include an NTN access network such as the 3GPP Satellite Access Node (SAN) which comprises Non-NTN infrastructure base station functions (e.g. eNB / gNB) a terrestrial Gateway which provides the interface to the feeder link to an NTN payload RF node. In some embodiments a network node QQ110 comprises a SAN, wherein the location of base station functions for a network node QQ110 (described above for the general terrestrial access) vary between residing in the terrestrial access network node part of the SAN and the NTN Payload RF node functions depending on the supported architecture. One example of NTN architecture is called bent pipe or transparent architecture where the radio frequency processing function (transceiver) on a satellite platform is interconnected with a terrestrial base station, also known as transparent architecture, and the NTN payload is passed transparently, no unpacking. Another example of NTN architecture is called regenerative architecture, where part or all of the eNB / gNB can be in the satellite.

[0073] In some examples a SAN includes an open radio unit (O-RU), an open distributed unit (O-DU), an open central unit (O-CU), including an O-CU control plane (O-CU-CP) or an O-CU user plane (O-CU-UP), a RAN intelligent controller (near-real time or non-real time) hosting software or software plug-ins, such as a near-real time control application (e.g., xApp) or a non- real time control application (e.g., rApp), or any combination thereof (the adjective “open” designating support of an ORAN specification).

[0074] Example wireless communications over a wireless connection include transmiting and / or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and / or other types of signals suitable for conveying information without the use of wires, cables, or other material conductors. Moreover, in different embodiments, the communication system QQ100 may include any number of wired or wireless networks, network nodes, UEs, and / or any other components or systems that may facilitate or participate in the communication of data and / or signals whether via wired or wireless connections. The communication system QQ100 may include and / or interface with any type of communication, telecommunication, data, cellular, radio network, and / or other similar type of system.

[0075] The UEs QQ112 may be any of a wide variety of communication devices, including wireless devices arranged, configured, and / or operable to communicate wirelessly with the network nodes QQ110 and other communication devices. Similarly, the network nodes QQ110 are arranged, capable, configured, and / or operable to communicate directly or indirectly with the UEs QQ112 and / or with other network nodes or equipment in the telecommunication network QQ102 to enable and / or provide network access, such as wireless network access, and / or to perform other functions, such as administration in the telecommunication network QQ102.

[0076] In the depicted example, the core network QQ106 connects the network nodes QQ110 to one or more host computing systems, such as host QQ116. These connections may be direct or indirect via one or more intermediary networks or devices. In other examples, network nodes may be directly coupled to hosts. The core network QQ106 includes one more core network nodes (e.g., core network node QQ108) that are structured with hardware and software components. Features of these components may be substantially similar to those described with respect to the UEs, network nodes, and / or hosts, such that the descriptions thereof are generally applicable to the corresponding components of the core network node QQ108. Example core network nodes include functions of one or more of a Mobile Switching Center (MSC), Mobility Management Entity (MME), Home Subscriber Server (HSS), Access and Mobility Management Function (AMF), Session Management Function (SMF), Authentication Server Function (AUSF), Subscription Identifier De-concealing function (SIDF), Unified Data Management (UDM), Security Edge Protection Proxy (SEPP), Network Exposure Function (NEF), and / or a User Plane Function (UPF).

[0077] The 0AM system would exist in both the core network QQ 106 and the access network QQ104, to configure the network nodes QQ110 with parameters for the purpose of operations, administration, and maintenance. For example, an 0AM function in a core network node QQ108configures a CLI mitigation time window to network nodes QQ110A as the allowable amount of time for the network nodes QQ110A to perform CLI mitigation once it is notified.

[0078] The host QQ116 may be under the ownership or control of a service provider other than an operator or provider of the access network QQ104 and / or the telecommunication network QQ102. The host QQ116 may host a variety of applications to provide one or more service. Examples of such applications include live and pre-recorded audio / video content, data collection services such as retrieving and compiling data on various ambient conditions detected by a plurality of UEs, analytics functionality, social media, functions for controlling or otherwise interacting with remote devices, functions for an alarm and surveillance center, or any other such function performed by a server.

[0079] As a whole, the communication system QQ100 of Figure 6 enables connectivity between the UEs, network nodes, and hosts. In that sense, the communication system may be configured to operate according to predefined rules or procedures, such as specific standards that include, but are not limited to: Global System for Mobile Communications (GSM); Universal Mobile Telecommunications System (UMTS); Long Term Evolution (LTE), and / or other suitable 2G, 3G, 4G, 5G standards, or any applicable future generation standard (e.g., 6G); wireless local area network (WLAN) standards, such as the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards (WiFi); and / or any other appropriate wireless communication standard, such as the Worldwide Interoperability for Microwave Access (WiMax), Bluetooth, Z-Wave, Near Field Communication (NFC) ZigBee, LiFi, and / or any low-power wide-area network (LPWAN) standards such as LoRa and Sigfox.

[0080] In some examples, the telecommunication network QQ102 is a cellular network that implements 3GPP standardized features. Accordingly, the telecommunications network QQ102 may support network slicing to provide different logical networks to different devices that are connected to the telecommunication network QQ102. For example, the telecommunications network QQ102 may provide Ultra Reliable Low Latency Communication (URLLC) services to some UEs, while providing Enhanced Mobile Broadband (eMBB) services to other UEs, and / or Massive Machine Type Communication (mMTC) / Massive loT services to yet further UEs.

[0081] In some examples, the UEs QQ112 are configured to transmit and / or receive information without direct human interaction. For instance, a UE may be designed to transmit information to the access network QQ104 on a predetermined schedule, when triggered by an internal or external event, or in response to requests from the access network QQ104. Additionally, a UE may be configured for operating in different cases as shown in Figure 4, so that cross-link interference might happen between different wireless communication links.

[0082] Figure 7 shows a network node QQ300 in accordance with some embodiments. As used herein, network node refers to equipment capable, configured, arranged and / or operable to communicate directly or indirectly with a UE and / or with other network nodes or equipment, in a telecommunication network. Examples of network nodes include, but are not limited to, access points (APs) (e.g., radio access points), base stations (BSs) (e.g., radio base stations, Node Bs, evolved Node Bs (eNBs) and NR NodeBs (gNBs)), O-RAN nodes or components of an O-RAN node (e.g., O-RU, O-DU, O-CU), components of a satellite access network (SAN) (e.g., terrestrial base station, gateway, NTN payload RF function).

[0083] Base stations may be categorized based on the amount of coverage they provide (or, stated differently, their transmit power level) and so, depending on the provided amount of coverage, may be referred to as femto base stations, pico base stations, micro base stations, or macro base stations. A base station may be a relay node or a relay donor node controlling a relay. A network node may also include one or more (or all) parts of a distributed radio base station such as centralized digital units, distributed units (e.g., in an O-RAN access node) and / or remote radio units (RRUs), sometimes referred to as Remote Radio Heads (RRHs). Such remote radio units may or may not be integrated with an antenna as an antenna integrated radio. Parts of a distributed radio base station may also be referred to as nodes in a distributed antenna system (DAS).

[0084] Other examples of network nodes include multiple transmission point (multi-TRP) 5G access nodes, multi-standard radio (MSR) equipment such as MSR BSs, network controllers such as radio network controllers (RNCs) or base station controllers (BSCs), base transceiver stations (BTSs), transmission points, transmission nodes, multi-cell / multicast coordination entities (MCEs), Operation and Maintenance (O&M) nodes, Operations Support System (OSS) nodes, Self-Organizing Network (SON) nodes, positioning nodes (e.g., Evolved Serving Mobile Location Centers (E-SMLCs)), and / or Minimization of Drive Tests (MDTs).

[0085] The network node QQ300 includes a processing circuitry QQ302, a memory QQ304, a communication interface QQ306, and a power source QQ308. The network node QQ300 may be composed of multiple physically separate components (e.g., a NodeB component and a RNC component, or a BTS component and a BSC component, etc.), which may each have their own respective components. In certain scenarios in which the network node QQ300 comprises multiple separate components (e.g., BTS and BSC components), one or more of the separate components may be shared among several network nodes. For example, a single RNC may control multiple NodeBs. In such a scenario, each unique NodeB and RNC pair, may in some instances be considered a single separate network node. In some embodiments, the network node QQ300 may be configured to support multiple radio access technologies (RATs). In such embodiments, some components may be duplicated (e.g., separate memory QQ304 for different RATs) and somecomponents may be reused (e.g., a same antenna QQ31O may be shared by different RATs). The network node QQ3OO may also include multiple sets of the various illustrated components for different wireless technologies integrated into network node QQ300, for example GSM, WCDMA, LTE, NR, WiFi, Zigbee, Z-wave, LoRaWAN, Radio Frequency Identification (RFID) or Bluetooth wireless technologies. These wireless technologies may be integrated into the same or different chip or set of chips and other components within network node QQ300.

[0086] The processing circuitry QQ302 may comprise a combination of one or more of a microprocessor, controller, microcontroller, central processing unit, digital signal processor, application-specific integrated circuit, field programmable gate array, or any other suitable computing device, resource, or combination of hardware, software and / or encoded logic operable to provide, either alone or in conjunction with other network node QQ300 components, such as the memory QQ304, to provide network node QQ300 functionality.

[0087] In some embodiments, the processing circuitry QQ302 includes a system on a chip (SOC). In some embodiments, the processing circuitry QQ302 includes one or more of radio frequency (RF) transceiver circuitry QQ312 and baseband processing circuitry QQ314. In some embodiments, the radio frequency (RF) transceiver circuitry QQ312 and the baseband processing circuitry QQ314 may be on separate chips (or sets of chips), boards, or units, such as radio units and digital units. In alternative embodiments, part or all of RF transceiver circuitry QQ312 and baseband processing circuitry QQ314 may be on the same chip or set of chips, boards, or units.

[0088] The memory QQ304 may comprise any form of volatile or non-volatile computer- readable memory including, without limitation, persistent storage, solid-state memory, remotely mounted memory, magnetic media, optical media, random access memory (RAM), read-only memory (ROM), mass storage media (for example, a hard disk), removable storage media (for example, a flash drive, a Compact Disk (CD) or a Digital Video Disk (DVD)), and / or any other volatile or non-volatile, non-transitory device-readable and / or computer-executable memory devices that store information, data, and / or instructions that may be used by the processing circuitry QQ302. The memory QQ304 may store any suitable instructions, data, or information, including a computer program, software, an application including one or more of logic, rules, code, tables, and / or other instructions capable of being executed by the processing circuitry QQ302 and utilized by the network node QQ300. The memory QQ304 may be used to store any calculations made by the processing circuitry QQ302 and / or any data received via the communication interface QQ306. In some embodiments, the processing circuitry QQ302 and memory QQ304 is integrated.

[0089] The communication interface QQ306 is used in wired or wireless communication of signaling and / or data between a network node, access network, and / or UE. As illustrated, the communication interface QQ306 comprises port(s) / terminal(s) QQ316 to send and receive data,for example to and from a network over a wired connection. The communication interface QQ306 also includes radio front-end circuitry QQ318 that may be coupled to, or in certain embodiments a part of, the antenna QQ310. Radio front-end circuitry QQ318 comprises filters QQ320 and amplifiers QQ322. The radio front-end circuitry QQ318 may be connected to an antenna QQ310 and processing circuitry QQ302. The radio front-end circuitry may be configured to condition signals communicated between antenna QQ310 and processing circuitry QQ302. The radio frontend circuitry QQ318 may receive digital data that is to be sent out to other network nodes or UEs via a wireless connection. The radio front-end circuitry QQ318 may convert the digital data into a radio signal having the appropriate channel and bandwidth parameters using a combination of filters QQ320 and / or amplifiers QQ322. The radio signal may then be transmitted via the antenna QQ310. Similarly, when receiving data, the antenna QQ310 may collect radio signals which are then converted into digital data by the radio front-end circuitry QQ318. The digital data may be passed to the processing circuitry QQ302. In other embodiments, the communication interface may comprise different components and / or different combinations of components.

[0090] In certain alternative embodiments, the network node QQ300 does not include separate radio front-end circuitry QQ318, instead, the processing circuitry QQ302 includes radio front-end circuitry and is connected to the antenna QQ310. Similarly, in some embodiments, all or some of the RF transceiver circuitry QQ312 is part of the communication interface QQ306. In still other embodiments, the communication interface QQ306 includes one or more ports or terminals QQ316, the radio front-end circuitry QQ318, and the RF transceiver circuitry QQ312, as part of a radio unit (not shown), and the communication interface QQ306 communicates with the baseband processing circuitry QQ314, which is part of a digital unit (not shown).

[0091] The antenna QQ310 may include one or more antennas, or antenna arrays, configured to send and / or receive wireless signals. The antenna QQ310 may be coupled to the radio front-end circuitry QQ318 and may be any type of antenna capable of transmitting and receiving data and / or signals wirelessly. In certain embodiments, the antenna QQ310 is separate from the network node QQ300 and connectable to the network node QQ300 through an interface or port.

[0092] The antenna QQ310, communication interface QQ306, and / or the processing circuitry QQ302 may be configured to perform any receiving operations and / or certain obtaining operations described herein as being performed by the network node. Any information, data and / or signals may be received from a UE, another network node and / or any other network equipment. Similarly, the antenna QQ310, the communication interface QQ306, and / or the processing circuitry QQ302 may be configured to perform any transmitting operations described herein as being performed by the network node. Any information, data and / or signals may be transmitted to a UE, another network node and / or any other network equipment.

[0093] The power source QQ308 provides power to the various components of network node QQ300 in a form suitable for the respective components (e.g., at a voltage and current level needed for each respective component). The power source QQ308 may further comprise, or be coupled to, power management circuitry to supply the components of the network node QQ300 with power for performing the functionality described herein. For example, the network node QQ300 may be connectable to an external power source (e.g., the power grid, an electricity outlet) via an input circuitry or interface such as an electrical cable, whereby the external power source supplies power to power circuitry of the power source QQ308. As a further example, the power source QQ308 may comprise a source of power in the form of a battery or battery pack which is connected to, or integrated in, power circuitry. The battery may provide backup power should the external power source fail.

[0094] Embodiments of the network node QQ300 may include additional components beyond those shown in Figure 7 for providing certain aspects of the network node’s functionality, including any of the functionality described herein and / or any functionality necessary to support the subject matter described herein. For example, the network node QQ300 may include user interface equipment to allow input of information into the network node QQ300 and to allow output of information from the network node QQ300. This may allow a user to perform diagnostic, maintenance, repair, and other administrative functions for the network node QQ300. In some embodiments providing a core network node, such as core network node 108 of FIG. QQ1, some components, such as the radio front-end circuitry QQ318 and the RF transceiver circuitry QQ312 may be omitted.

[0095] Although the computing devices described herein (e.g., UEs, network 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, which may process 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, computing devices may comprise multiple different physical components that make up a single illustrated component, and functionality may be partitioned between separate components. For example, a communication interface may be configured toinclude any of the components described herein, and / or the functionality of the components may be partitioned between the processing circuitry and the communication interface. In another example, non-computationally intensive functions of any of such components may be implemented in software or firmware and computationally intensive functions may be implemented in hardware.

[0096] In certain embodiments, some or all of the functionality described herein may be provided by processing circuitry executing instructions stored on in memory, which in certain embodiments may be a computer program product in the form of a non-transitory computer- readable storage medium. In alternative embodiments, some or all of the functionality may be provided by the processing circuitry without executing instructions stored on a separate or discrete device-readable storage medium, such as in a hard-wired manner. In any of those particular embodiments, whether executing instructions stored on a non-transitory computer-readable storage medium or not, the processing circuitry can be configured to perform the described functionality. The benefits provided by such functionality are not limited to the processing circuitry alone or to other components of the computing device, but are enjoyed by the computing device as a whole, and / or by end users and a wireless network generally.EMBODIMENT EXAMPLESA Embodiments1. A method performed by a first network node for interference mitigation, the method comprising:- transmitting one or more reference signal configurations to a second network node, the reference signal configurations comprising configurations of reference signals that the second network node should measure to determine an amount of cross link interference (CLI);- receiving a request for CLI mitigation from the second network node, the request comprising an indication of one or more reference signals causing CLI; and- performing CLI mitigation by nulling transmission of the one or more reference signals causing CLI.2. The method of the previous embodiment, wherein the one or more reference signal configurations comprise configurations for a channel state information reference signal (CSI-RS) or a synchronization signal block (SSB).3. The method of any one of the previous two embodiments, wherein the one or more reference signal configurations is limited to a threshold number of configurations.4. The method of any one of the previous three embodiments, wherein the one or more reference signal configurations comprises groups of reference signal configurations, wherein each group of reference signal configurations is associated with a same beam.5. The method of any one of the previous four embodiments, wherein the one or more reference signal configurations further comprises an indication of a maximum number of reference signals for which the first network node will perform CLI mitigation.6. The method of any one of the previous five embodiments, wherein the one or more reference signal configurations further comprises an indication of a time duration for which the first network node will perform CLI mitigation.7. The method of any one of the previous six embodiments, wherein the request for CLImitigation further comprises a number of CLI mitigation periods for which the second network node would like the first network node to perform CLI mitigation.8. The method of any one of the previous seven embodiments, wherein the request for CLI mitigation further comprises one or more signal strength indicators.9. A method performed by a second network node for interference mitigation, the method comprising:- receiving one or more reference signal configurations from a first network node, the reference signal configurations comprising configurations of reference signals that the second network node should measure to determine an amount of cross link interference (CLI);- measuring one or more of the reference signals according to the received reference signal configurations; and- transmitting a request for CLI mitigation to the first network node, the request comprising an indication of one or more reference signals causing CLI.10. The method of the previous embodiment, wherein the one or more reference signal configurations comprise configurations for a channel state information reference signal (CSI-RS) or a synchronization signal block (SSB).11. The method of any one of the previous two embodiments, wherein the one or more reference signal configurations is limited to a threshold number of configurations.12. The method of any one of the previous three embodiments, wherein the one or more reference signal configurations comprises groups of reference signal configurations, wherein each group of reference signal configurations is associated with a same beam.13. The method of any one of the previous four embodiments, wherein the one or more reference signal configurations further comprises an indication of a maximum number of reference signals for which the first network node will perform CLI mitigation, and the request for CLI mitigation does not include more identifiers of reference signals than the indicated maximum number.14. The method of any one of the previous five embodiments, wherein the one or morereference signal configurations further comprises an indication of a time duration for which the first network node will perform CLI mitigation.15. The method of any one of the previous six embodiments, wherein the request for CLI mitigation further comprises a number of CLI mitigation periods for which the second network node would like the first network node to perform CLI mitigation.16. The method of any one of the previous seven embodiments, wherein the request for CLI mitigation further comprises one or more signal strength indicators.17. A method performed by a network node, the method comprising:- any of the steps, features, or functions described above with respect to a network node, either alone or in combination with other steps, features, or functions described above.18. The method of the previous embodiment, further comprising one or more additional network node steps, features or functions described above. up B Embodiments19. A network node, the network node comprising: processing circuitry configured to perform any of the steps of any of the Group B embodiments; power supply circuitry configured to supply power to the processing circuitry.

Claims

CLAIMS1. A method performed by a first network node for interference mitigation, comprising: transmitting, to a second network node, one or more reference signal, RS, configurations based on which the second network node measures cross link interference, CLI, on reference signals; and receiving, from the second network node, information on CLI measurement result on the reference signals according to the one or more RS configurations.

2. The method of Claim 1, wherein the one or more RS configurations comprise one or more configurations for channel state information reference signal, CSI-RS, and comprise resources for the CSI-RS indicated by non-zero power, NZP, NZP-CSI-RS-ResourceSet.

3. The method of Claim 1, wherein the one or more RS configurations comprise one or more configurations for synchronization signal block, SSB.

4. The method of any of Claims 1 to 3, wherein the one or more RS configurations are limited to a threshold number of configurations which is smaller than a scope that is configurable by the first network node.

5. The method of any of Claims 1 to 4, wherein the transmitting one or more RS configurations comprises: transmitting one or more groups of the one or more RS configurations where each group is associated with a same beam.

6. The method of any of Claims 1 to 5, wherein the information on CLI measurement result comprises an indicator for a strongest RS or beam received according to the one or more RS configurations or RS configuration groups; and / or the method further comprising: receiving from the second network node, a request for CLI mitigation.

7. The method of any of Claims 1 to 6, further comprising: receiving an indication of an RS configuration for which the first network node can use for CLI mitigation.

8. The method of any of Claims 1 to 7, further comprising: determining to execute a CLI mitigation action by nulling signal transmissions on interfered resources corresponding to the information on CLI measurement result.

9. The method of any of Claims 1 to 8, wherein the information on CLI measurement result further comprises one or more received signal strength indicator(s) of the received RSs according to the one or more RS configurations.

10. The method of any of Claims 1 to 9, further comprising: receiving, from a management network node, information on a CLI mitigation time window once the first network node determines to execute a CLI mitigation action.

11. A first network node (QQ300) configured for interference mitigation, comprising: a processing circuitry (QQ302), and a memory (QQ304) for storing instructions which when executed by the processing circuitry, causes the first network node to perform steps of any of Claims 1 to 10.

12. A method performed by a second network node for interference mitigation, comprising: receiving, from a first network node, one or more RS configurations so that the second network node can perform CLI measurement on reference signals; transmitting, to the first network node, information on CLI measurement result on the reference signals received according to the one or more RS configurations.

13. The method of Claim 12, wherein the one or more RS configurations comprise one or more configurations for CSI-RS and comprise resources for the CSI-RS indicated by NZP-CSI-RS- ResourceSet.

14. The method of Claim 13, wherein the information on CLI measurement result comprises an indicator for a strongest CSI-RS or CSI-RS beam received according to the one or more RS configurations.

15. The method of any of Claims 12 to 14, wherein the one or more RS configurations comprise one or more configurations for synchronization signal block, SSB, wherein the information on CLI measurement result comprises an indicator for a strongest SSB or SSB beam received according to the one or more RS configurations.

16. The method of any of Claims 12 to 15, wherein the one or more RS configurations are limited to a threshold number of configurations which is smaller than a scope that is configurable by the first network node.

17. The method of any of Claims 12 to 16, wherein the method further comprising: transmitting, to the first network node, a request for CLI mitigation.

18. The method of any of Claims 12 to 17, further comprising: transmitting, to the first network node, an indication of an RS configuration for which can be used by the first network node for CLI mitigation.

19. A second network node configured for interference mitigation, comprising: a processing circuitry (QQ302), and a memory (QQ304) for storing instructions which when executed by the processing circuitry, causes the second network node to perform steps of any of Claims 12 to 18.

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