Coordination for mitigating cross-link interference

Abstract

Disclosed is a method comprising transmitting, to a second network entity, a configuration indicating one or more resources to be used for measuring cross-link interference between the first network entity and the second network entity; receiving, from the second network entity, a cross-link interference measurement report indicating a result of the measurement for one or more beam pairs associated with the first network entity and the second network entity; and coordinating with the second network entity based on the cross-link interference measurement report for mitigating the cross-link interference.

Description

COORDINATION FOR MITIGATING CROSS-LINK INTERFERENCETECHNICAL FIELD

[0001] The following example embodiments relate to wireless communication and to cross-link interference.BACKGROUND

[0002] Cross-link interference refers to the undesired interference between two separate communication links in a wireless communication system. This interference may occur when the signal from one link, which is intended for a specific receiver, interferes with another link in the opposite link direction, causing a degradation of the communication quality or performance. It is desirable to protect the links from cross-link interference.BRIEF DESCRIPTION

[0003] The scope of protection sought for various example embodiments is set out by the claims. The example embodiments and features, if any, described in this specification that do not fall under the scope of the claims are to be interpreted as examples useful for understanding various embodiments.

[0004] According to an aspect, there is provided an apparatus comprising at least one processor, and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to: transmit, to a second network entity, a configuration indicating one or more resources to be used for measuring cross-link interference between the first network entity and the second network entity; receive, from the second network entity, a cross-link interference measurement report indicating a result of the measurement for one or more beam pairs associated with the first network entity and the second network entity; and coordinate with the second network entity based on the cross-link interference measurement report for mitigating the crosslink interference.

[0005] According to another aspect, there is provided an apparatus comprising: means for transmitting, to a second network entity, a configurationindicating one or more resources to be used for measuring cross-link interference between the first network entity and the second network entity; means for receiving, from the second network entity, a cross-link interference measurement report indicating a result of the measurement for one or more beam pairs associated with the first network entity and the second network entity; and means for coordinating with the second network entity based on the cross-link interference measurement report for mitigating the cross-link interference.

[0006] According to another aspect, there is provided a method comprising: transmitting, to a second network entity, a configuration indicating one or more resources to be used for measuring cross-link interference between the first network entity and the second network entity; receiving, from the second network entity, a cross-link interference measurement report indicating a result of the measurement for one or more beam pairs associated with the first network entity and the second network entity; and coordinating with the second network entity based on the cross-link interference measurement report for mitigating the cross-link interference.

[0007] According to another aspect, there is provided a computer program comprising instructions which, when executed by an apparatus, cause the apparatus to perform at least the following: transmitting, to a second network entity, a configuration indicating one or more resources to be used for measuring cross-link interference between the first network entity and the second network entity; receiving, from the second network entity, a cross-link interference measurement report indicating a result of the measurement for one or more beam pairs associated with the first network entity and the second network entity; and coordinating with the second network entity based on the cross-link interference measurement report for mitigating the cross-link interference.

[0008] According to another aspect, there is provided a computer readable medium comprising program instructions which, when executed by an apparatus, cause the apparatus to perform at least the following: transmitting, to a second network entity, a configuration indicating one or more resources to be used for measuring cross-link interference between the first network entity and thesecond network entity; receiving, from the second network entity, a cross-link interference measurement report indicating a result of the measurement for one or more beam pairs associated with the first network entity and the second network entity; and coordinating with the second network entity based on the cross-link interference measurement report for mitigating the cross-link interference.

[0009] According to another aspect, there is provided a non-transitory computer readable medium comprising program instructions which, when executed by an apparatus, cause the apparatus to perform at least the following: transmitting, to a second network entity, a configuration indicating one or more resources to be used for measuring cross-link interference between the first network entity and the second network entity; receiving, from the second network entity, a cross-link interference measurement report indicating a result of the measurement for one or more beam pairs associated with the first network entity and the second network entity; and coordinating with the second network entity based on the cross-link interference measurement report for mitigating the crosslink interference.

[0010] According to another aspect, there is provided an apparatus comprising at least one processor, and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to: receive, from a first network entity, a configuration indicating one or more resources to be used for measuring cross-link interference between the first network entity and the second network entity; perform, based on the configuration, the measurement of the cross-link interference on the one or more resources for one or more beam pairs associated with the first network entity and the second network entity; transmit, to the first network entity, a cross-link interference measurement report indicating a result of the measurement for the one or more beam pairs associated with the first network entity and the second network entity; and coordinate with the first network entity based on the crosslink interference measurement report for mitigating the cross-link interference.

[0011] According to another aspect, there is provided an apparatus comprising: means for receiving, from a first network entity, a configuration indicating one or more resources to be used for measuring cross-link interference between the first network entity and the second network entity; means for performing, based on the configuration, the measurement of the cross-link interference on the one or more resources for one or more beam pairs associated with the first network entity and the second network entity; means for transmitting, to the first network entity, a cross-link interference measurement report indicating a result of the measurement for the one or more beam pairs associated with the first network entity and the second network entity; and means for coordinating with the first network entity based on the cross-link interference measurement report for mitigating the cross-link interference.

[0012] According to another aspect, there is provided a method comprising: receiving, from a first network entity, a configuration indicating one or more resources to be used for measuring cross-link interference between the first network entity and the second network entity; performing, based on the configuration, the measurement of the cross-link interference on the one or more resources for one or more beam pairs associated with the first network entity and the second network entity; transmitting, to the first network entity, a cross-link interference measurement report indicating a result of the measurement for the one or more beam pairs associated with the first network entity and the second network entity; and coordinating with the first network entity based on the crosslink interference measurement report for mitigating the cross-link interference.

[0013] According to another aspect, there is provided a computer program comprising instructions which, when executed by an apparatus, cause the apparatus to perform at least the following: receiving, from a first network entity, a configuration indicating one or more resources to be used for measuring crosslink interference between the first network entity and the second network entity; performing, based on the configuration, the measurement of the cross-link interference on the one or more resources for one or more beam pairs associated with the first network entity and the second network entity; transmitting, to thefirst network entity, a cross-link interference measurement report indicating a result of the measurement for the one or more beam pairs associated with the first network entity and the second network entity; and coordinating with the first network entity based on the cross-link interference measurement report for mitigating the cross-link interference.

[0014] According to another aspect, there is provided a computer readable medium comprising program instructions which, when executed by an apparatus, cause the apparatus to perform at least the following: receiving, from a first network entity, a configuration indicating one or more resources to be used for measuring cross-link interference between the first network entity and the second network entity; performing, based on the configuration, the measurement of the cross-link interference on the one or more resources for one or more beam pairs associated with the first network entity and the second network entity; transmitting, to the first network entity, a cross-link interference measurement report indicating a result of the measurement for the one or more beam pairs associated with the first network entity and the second network entity; and coordinating with the first network entity based on the cross-link interference measurement report for mitigating the cross-link interference.

[0015] According to another aspect, there is provided a non-transitory computer readable medium comprising program instructions which, when executed by an apparatus, cause the apparatus to perform at least the following: receiving, from a first network entity, a configuration indicating one or more resources to be used for measuring cross-link interference between the first network entity and the second network entity; performing, based on the configuration, the measurement of the cross-link interference on the one or more resources for one or more beam pairs associated with the first network entity and the second network entity; transmitting, to the first network entity, a cross-link interference measurement report indicating a result of the measurement for the one or more beam pairs associated with the first network entity and the second network entity; and coordinating with the first network entity based on the crosslink interference measurement report for mitigating the cross-link interference.LIST OF DRAWINGS

[0016] In the following, various example embodiments will be described in greater detail with reference to the accompanying drawings, in which FIG. 1A illustrates an example of a wireless communication network; FIG. IB illustrates an example of a system;FIG. 2 illustrates a signal flow diagram;FIG. 3 illustrates a signal flow diagram;FIG. 4 illustrates a flow chart;FIG. 5 illustrates a flow chart;FIG. 6 illustrates a flow chart; andFIG. 7 illustrates an example of an apparatus.DETAILED DESCRIPTION

[0017] The following embodiments are exemplifying. Although the specification may refer to “an”, “one”, or “some” embodiment(s) in several locations of the text, this does not necessarily mean that each reference is made to the same embodiment(s), or that a particular feature only applies to a single embodiment. Single features of different embodiments may also be combined to provide other embodiments. Furthermore, the words "comprising" and "including" should be understood as not limiting the described embodiments to consist of only those features that have been mentioned, and such embodiments may also contain features that have not been specifically mentioned. Reference numbers, in the description and / or in the claims, serve to illustrate the embodiments with reference to the drawings, without limiting the embodiments to these examples only.

[0018] Some example embodiments described herein may be implemented in a wireless communication network comprising a radio access network based on one or more of the following radio access technologies (RATs): global system for mobile communications (GSM) or any other second generation (2G) radio access technology, universal mobile telecommunication system (UMTS, 3G) based on basic wideband-code division multiple access (W-CDMA), high-speedpacket access (HSPA), long term evolution (LTE), LTE -Advanced, fourth generation (4G), fifth generation (5G), 5G new radio (NR), 5G-Advanced (i.e., 3GPP NR Rel-18 and beyond), or sixth generation (6G). Some examples of radio access networks include the universal mobile telecommunications system (UMTS) radio access network (UTRAN), the evolved universal terrestrial radio access network (E- UTRA), or the next generation radio access network (NG-RAN). The wireless communication network may further comprise a core network, and some example embodiments may also be applied to network functions of the core network.

[0019] It should be noted that the embodiments are not restricted to the wireless communication network given as an example, but a person skilled in the art may also apply the solution to other wireless communication networks or systems provided with necessary properties. For example, some example embodiments may also be applied to a communication system based on IEEE 802.11 specifications, or a communication system based on IEEE 802.15 specifications. IEEE is an abbreviation for the Institute of Electrical and Electronics Engineers.

[0020] FIG. 1A depicts an example of a simplified wireless communication network showing some physical and logical entities. The connections shown in FIG. 1A may be physical connections or logical connections. It is apparent to a person skilled in the art that the wireless communication network may also comprise other physical and logical entities than those shown in FIG. 1A.

[0021] The example embodiments described herein are not, however, restricted to the wireless communication network given as an example but a person skilled in the art may apply the example embodiments described herein to other wireless communication networks provided with necessary properties.

[0022] The example wireless communication network shown in FIG. 1A includes a radio access network (RAN) and a core network 110.

[0023] FIG. 1A shows user equipment (UE) 100, 102 configured to be in a wireless connection on one or more communication channels in a radio cell with an access node 104 of a radio access network.

[0024] The access node 104 may comprise a computing device configured to control the radio resources of the access node 104 and to be in a wireless connection with one or more UEs 100, 102. The access node 104 may also be referred to as a base station, a base transceiver station (BTS), an access point, a cell site, a network node, a radio access network node, or a RAN node. In this description, the terms “access node” and “radio access network node” may be used interchangeably.

[0025] The access node 104 may be, for example, an evolved NodeB (abbreviated as eNB or eNodeB), or a next generation evolved NodeB (abbreviated as ng-eNB), or a next generation NodeB (abbreviated as gNB or gNodeB), providing the radio cell. The access node 104 may include or be coupled to transceivers. From the transceivers of the access node 104, a connection may be provided to an antenna unit that establishes a bi-directional radio link to one or more UEs 100, 102. The antenna unit may comprise an antenna or antenna element, or a plurality of antennas or antenna elements.

[0026] The wireless connection (e.g., radio link) from a UE 100, 102 to the access node 104 may be called uplink (UL) or reverse link, and the wireless connection (e.g., radio link) from the access node 104 to the UE 100, 102 may be called downlink (DL) or forward link. A UE 100 may also communicate directly with another UE 102, and vice versa, via a wireless connection generally referred to as a sidelink (SL). It should be appreciated that the access node 104 or its functionalities may be implemented by using any node, host, server, access point or other entity suitable for providing such functionalities.

[0027] The radio access network may comprise more than one access node 104, in which case the access nodes may also be configured to communicate with one another over wired or wireless links. These links between access nodes may be used for sending and receiving control plane signaling and also for routing data from one access node to another access node.

[0028] The access node 104 may further be connected to a core network (CN) 110. The core network 110 may comprise an evolved packet core (EPC) network and / or a 5thgeneration core network (5GC). The EPC may comprisenetwork entities, such as a serving gateway (S-GW for routing and forwarding data packets), a packet data network gateway (P-GW) for providing connectivity of UEs to external packet data networks, and / or a mobility management entity (MME). The 5GC may comprise one or more network functions, such as at least one of: a user plane function (UPF), an access and mobility management function (AMF), a location management function (LMF), and / or a session management function (SMF).

[0029] The core network 110 may also be able to communicate with one or more external networks 113, such as a public switched telephone network or the Internet, or utilize services provided by them. For example, in 5G wireless communication networks, the UPF of the core network 110 may be configured to communicate with an external data network via an N6 interface. In LTE wireless communication networks, the P-GW of the core network 110 may be configured to communicate with an external data network.

[0030] It should also be understood that the distribution of functions between core network operations and access node operations may differ in future wireless communication networks compared to that of the LTE or 5G, or even be non-existent.

[0031] The illustrated UE 100, 102 is one type of an apparatus to which resources on the air interface may be allocated and assigned. The UE 100, 102 may also be called a wireless communication device, a subscriber unit, a mobile station, a remote terminal, an access terminal, a user terminal, a terminal device, or a user device, just to mention but a few names. The UE 100, 102 may be a computing device operating with or without a subscriber identification module (SIM), including, but not limited to, the following types of computing devices: a mobile phone, a smartphone, a personal digital assistant (PDA), a handset, a computing device comprising a wireless modem (e.g., an alarm or measurement device, etc.), a laptop computer, a desktop computer, a tablet, a game console, a notebook, a multimedia device, a reduced capability (RedCap) device, a wearable device (e.g., a watch, earphones or eyeglasses) with radio parts, a sensor comprising a wirelessmodem, or a computing device comprising a wireless modem integrated in a vehicle.

[0032] It should be appreciated that the UE 100, 102 may also be a nearly exclusive uplink-only device, of which an example may be a camera or video camera loading images or video clips to a network. The UE 100, 102 may also be a device having capability to operate in an Internet of Things (loT) network, which is a scenario in which objects may be provided with the ability to transfer data over a network without requiring human-to-human or human-to-computer interaction.

[0033] The wireless communication network may also be able to support the usage of cloud services. For example, at least part of core network operations may be carried out as a cloud service (this is depicted in FIG. 1A by “cloud” 114). The UE 100, 102 may also utilize the cloud 114. In some applications, the computation for a given UE may be carried out in the cloud 114 or in another UE.

[0034] The wireless communication network may also comprise a central control entity, such as a network management system (NMS), or the like. The NMS is a centralized suite of software and hardware used to monitor, control, and administer the network infrastructure. The NMS is responsible for a wide range of tasks such as fault management, configuration management, security management, performance management, and accounting management. The NMS enables network operators to efficiently manage and optimize network resources, ensuring that the network delivers high performance, reliability, and security.

[0035] 5G enables using multiple-input and multiple-output (M1M0) antennas in the access node 104 and / or the UE 100, 102, many more base stations or access nodes than an LTE network (a so-called small cell concept), including macro sites operating in co-operation with smaller stations and employing a variety of radio technologies depending on service needs, use cases and / or spectrum available. 5G wireless communication networks may support a wide range of use cases and related applications including video streaming, augmented reality, different ways of data sharing and various forms of machine-typeapplications, such as (massive) machine-type communications (mMTC), including vehicular safety, different sensors and real-time control.

[0036] In 5G wireless communication networks, access nodes and / or UEs may have multiple radio interfaces, such as below 6 gigahertz (GHz), centimeter wave (cmWave) and millimeter wave (mmWave), and also being integrable with legacy radio access technologies, such as LTE. Integration with LTE may be implemented, for example, as a system, where macro coverage may be provided by LTE, and 5G radio interface access may come from small cells by aggregation to LTE. In other words, a 5G wireless communication network may support both inter-RAT operability (such as interoperability between LTE and 5G) and inter-Rl operability (inter-radio interface operability, such as between below 6GHz, cmWave, and mmWave).

[0037] 5G wireless communication networks may also apply network slicing, in which multiple independent and dedicated virtual sub-networks (network instances) may be created within the same physical infrastructure to run services that have different requirements on latency, reliability, throughput and mobility.

[0038] In one embodiment, an access node 104 may comprise: a radio unit (RU) comprising a radio transceiver (TRX), i.e., a transmitter (Tx) and a receiver (Rx); one or more distributed units (DUs) 105 that may be used for the so- called Layer 1 (LI) processing and real-time Layer 2 (L2) processing; and a central unit (CU) 108 (also known as a centralized unit) that may be used for non-real-time L2 and Layer 3 (L3) processing. The CU 108 may be connected to the one or more DUs 105 for example via an Fl interface. Such an embodiment of the access node 104 may enable the centralization of CUs relative to the cell sites and DUs, whereas DUs may be more distributed and may even remain at cell sites. The CU and DU together may also be referred to as baseband or a baseband unit (BBU). The CU and DU may also be comprised in a radio access point (RAP).

[0039] The CU 108 may be a logical node hosting radio resource control (RRC), service data adaptation protocol (SDAP) and / or packet data convergence protocol (PDCP), of the NR protocol stack for an access node 104. The CU 108 maycomprise a control plane (CU-CP), which may be a logical node hosting the RRC and the control plane part of the PDCP protocol of the NR protocol stack for the access node 104. The CU 108 may further comprise a user plane (CU-UP), which may be a logical node hosting the user plane part of the PDCP protocol and the SDAP protocol of the CU for the access node 104.

[0040] The DU 105 may be a logical node hosting radio link control (RLC), medium access control (MAC) and / or physical (PHY) layers of the NR protocol stack for the access node 104. The operations of the DU 105 may be at least partly controlled by the CU 108. It should also be understood that the distribution of functions between the DU 105 and the CU 108 may vary depending on the implementation.

[0041] Cloud computing systems may also be used to provide the CU 108 and / or DU 105. A CU provided by a cloud computing system may be referred to as a virtualized CU (vCU). In addition to the vCU, there may also be a virtualized DU (vDU) provided by a cloud computing system. Furthermore, there may also be a combination, where the DU may be implemented on so-called bare metal solutions, for example application-specific integrated circuit (ASIC) or customerspecific standard product (CSSP) system-on-a-chip (SoC).

[0042] Edge cloud may be brought into the radio access network by utilizing network function virtualization (NFV) and software defined networking (SDN). Using edge cloud may mean access node operations to be carried out, at least partly, in a computing system operationally coupled to a remote radio head (RRH) or a radio unit (RU) of an access node 104. It is also possible that access node operations may be performed on a distributed computing system or a cloud computing system located at the access node 104. Application of cloud RAN architecture enables RAN real-time functions being carried out at the radio access network (e.g., in a DU 105), and non-real-time functions being carried out in a centralized manner (e.g., in a CU 108).

[0043] 5G (or new radio, NR) wireless communication networks may support multiple hierarchies, where multi-access edge computing (MEC) servers may be placed between the core network 110 and the access node 104. It shouldbe appreciated that MEC may be applied in LTE wireless communication networks as well.

[0044] A 5G wireless communication network (“5G network”) may also comprise a non-terrestrial communication network, such as a satellite communication network, to enhance or complement the coverage of the 5G radio access network. For example, satellite communication may support the transfer of data between the 5G radio access network and the core network 110, enabling more extensive network coverage. Possible use cases may include: providing service continuity for machine-to-machine (M2M) or Internet of Things (loT) devices or for passengers on board of vehicles, or ensuring service availability for critical communications, and future railway, maritime, or aeronautical communications. Satellite communication may utilize geostationary earth orbit (GEO) satellite systems, but also low earth orbit (LEO) satellite systems, in particular mega-constellations (i.e., systems in which hundreds of (nano)satellites are deployed). A given satellite 106 in the mega-constellation may cover several satellite-enabled network entities that create on-ground cells. The on-ground cells may be created through an on-ground relay access node or by an access node located on-ground or in a satellite.

[0045] It is obvious for a person skilled in the art that the access node 104 depicted in FIG. 1A is just an example of a part of a radio access network, and in practice the radio access network may comprise a plurality of access nodes 104, the UEs 100, 102 may have access to a plurality of radio cells, and the radio access network may also comprise other apparatuses, such as physical layer relay access nodes or other entities. At least one of the access nodes may be a Home eNodeB or a Home gNodeB. A Home gNodeB or a Home eNodeB is a type of access node that may be used to provide indoor coverage inside a home, office, or other indoor environment.

[0046] Additionally, in a geographical area of a radio access network, a plurality of different kinds of radio cells as well as a plurality of radio cells may be provided. Radio cells may be macro cells (or umbrella cells) which may be large cells having a diameter of up to tens of kilometers, or smaller cells such as micro-,femto- or picocells. The access node(s) 104 of FIG. 1A may provide any kind of these cells. A cellular radio network may be implemented as a multilayer access networks including several kinds of radio cells. In multilayer access networks, one access node may provide one kind of a radio cell or radio cells, and thus a plurality of access nodes may be needed to provide such a multilayer access network.

[0047] For fulfilling the need for improving performance of radio access networks, the concept of “plug-and-play” access nodes may be introduced. A radio access network, which may be able to use “plug-and-play” access nodes, may include, in addition to Home eNodeBs or Home gNodeBs, a Home Node B gateway (HNB-GW) (not shown in FIG. 1A). An HNB-GW, which may be installed within an operator’s radio access network, may aggregate traffic from a large number of Home eNodeBs or Home gNodeBs back to a core network 110 of the operator.

[0048] Some example embodiments are described below using principles and terminology of 5G radio access technology without limiting the example embodiments to 5G radio access technology, however.

[0049] Some example embodiments relate to cross-link interference (CL1) handling and, more specifically, to spatial coordination schemes for mitigating CL1.

[0050] Cross-link interference refers to the undesired interference between two separate communication links in a wireless communication system. This interference may occur when the signal from one link, which is intended for a specific receiver, interferes with another link in the opposite link direction, causing a degradation of the communication quality or performance. Cross-link interference can occur between UEs, denoted as UE-to-UE CL1, and between gNBs, denoted as gNB-to-gNB CL1. CL1 may be an issue for, for example, dynamic timedivision duplexing (TDD), and sub-band non-overlapping full duplexing (SBFD).

[0051] SBFD is a duplexing scheme being introduced in 5G-Advanced, and it allows both DL and UL transmission opportunities within a given slot. In other words, SBFD allows simultaneous DL and UL transmission on different physical resource blocks (PRBs) or subbands.

[0052] In the context of cross-link interference, the node that is generating the interference is denoted as aggressor node or interfering node, while the node or nodes that are being interfered are denoted as victim nodes or interfered node.

[0053] FIG. IB illustrates an example of a system, to which some example embodiments may be applied. FIG. IB may be understood to depict a part of the wireless communication network of FIG. 1A, but with greater accuracy with respect to cross-link interference.

[0054] FIG. IB shows an example of gNB-to-gNB CLI between two gNBs 104A, 104B. gNB-to-gNB CLI occurs when the aggressor gNB (interfering node) 104A is transmitting in the DL, while the victim gNB (interfered node) 104B is receiving in the UL at the same time. Herein the aggressor gNB 104A may also be referred to as a first network entity, and the victim gNB 104B may also be referred to as a second network entity. It should be noted that the roles of the aggressor gNB and victim gNB may also be reversed depending on the direction of the scheduling.

[0055] FIG. IB also illustrates the UE-to-UE CLI that may occur if two UEs 100, 102 are located in close proximity to each other.

[0056] Assuming that both gNBs 104A, 104B apply beamforming as illustrated in FIG. IB, the gNB-to-gNB CLI may be significant only when the aggressor gNB 104A transmits on certain beam(s) 121, and the victim gNB 104B is receiving on particular beam(s) 131 at the same time. Therefore, it may be possible to mitigate the gNB-to-gNB CLI by using some form of inter-gNB beamforming coordination between the gNBs 104A, 104B.

[0057] The 5G NR access link may operate in the millimeter wave (mmWave), sub-terahertz (sub-THz) bands, and higher frequency ranges, which are intrinsically more susceptible to higher path loss and penetration loss. In the higher frequency ranges, both the gNBs and the UEs may employ front-end circuits with, for example, multiple beam patterns to combat the drawbacks of the propagation channel.

[0058] Herein a beam refers to directional transmission or reception of a radio signal. Beams may be formed using an advanced antenna technology calledbeamforming. Beamforming may be beneficial for example in 5G NR because of its ability to support higher frequency bands (e.g., mmWave frequencies) and its massive M1M0 capabilities. A beam may also be represented as a spatial filter, spatial direction, or angle. Beams may be classified into transmit beams 121, 122, 123, 124, 125 and receive beams 131, 132, 133, 134, 135. It should be noted that, in SBFD, a gNB can have the same beam (spatial direction, angle) being used for both DL and UL.

[0059] The gNB 104A may form one or more transmit beams (downlink beams) 121, 122, 123, 124, 125 to transmit downlink signals towards one or more UEs 100 in a specific direction. For example, by focusing the transmission energy in the direction of the intended UE 100 via the transmit beam 121, downlink beamforming can improve the signal strength and overall communication quality, while also minimizing interference with other UEs and reducing power consumption.

[0060] The gNB 104B may receive uplink signals from one or more UEs 102 via one or more receive beams 131, 132, 133, 134, 135. A receive beam is a focused radio wave pattern that the gNB 104B uses to receive signals from the one or more UEs 102. The one or more UEs 102 may form one or more uplink beams to transmit the uplink signals towards the gNB 104B in a specific direction.

[0061] The number of transmit or receive beams as shown in FIG. IB is one example, and the number of beams may be different according to the network entities’ ability or services.

[0062] Beamforming may involve the use of large antenna arrays at both the gNB and the UE, allowing for the formation of multiple beams simultaneously. This enables features such as spatial multiplexing and multi-user M1M0 (MU-M1M0), which can further increase the capacity and efficiency of the 5G network.

[0063] gNB-to-gNB CL1 may be present, for example, in dynamic TDD deployments, in which the gNBs can select the TDD frame configuration in an uncoordinated manner. CL1 may be present in the deployment, if a given slot is chosen to have opposite link directions for two or more gNBs. Similarly, in SBFDoperation, gNB-to-gNB CLI may occur, when two gNBs have a different DL / UL subband split and the subband of the opposite link direction overlaps, or when two gNBs have the same DL / UL subband. In the first case, the gNB-to-gNB CLI comes from overlapping resource blocks (RBs) and it is denoted as intra-subband CLI. In the latter case, the gNB-to-gNB CLI is denoted as inter-subband CLI, since the interference is generated from leakage in non-overlapping resources.

[0064] The cross-link interference problem may be solved by providing means to measure and report the CLI, and to proactively or reactively mitigate the interference. Some examples of CLI mitigation mechanisms may include, but are not limited to, coordinated scheduling and spatial domain enhancements.

[0065] For example, cell-defining synchronization signal block (CD- SSB) and / or non-cell-defining synchronization signal block (NCD-SSB) can be used for gNB-to-gNB CLI measurement.

[0066] For spatial domain enhancement of gNB-to-gNB co-channel CLI handling, DL transmit beam information of a gNB can be exchanged between gNBs. A reference signal resource identifier, such as a non-zero-power channel state information reference signal (NZP-CS1-RS) resource ID, or a synchronization signal block (SSB) index, can be used as beam information exchange between gNBs.

[0067] Some example embodiments address the signaling exchange to perform the beamforming coordination between network entities (e.g., gNBs or UEs) for mitigating CLI (e.g., in the context of dynamic TDD and SBFD).

[0068] Some example embodiments provide a method to enable mitigating gNB-to-gNB CLI, by defining a framework to exchange CLI measurements, CLI measurement reports and intended beams configuration between gNBs over the Xn interface. It should be noted that some example embodiments may also be used for mitigating UE-to-UE CLI in a similar manner.

[0069] Initially, a configuration of the CLI measurement resources and a configuration of the CLI measurement report may be performed. The measurement report may comprise, for example, a list including at least one of: the beam identifier(s) with the strongest measured CLI, the identifiers of the beams with CLI above a pre-configured threshold, or the measurement results for theconfigured resources. The measurements may be reported per transmit-receive beam pair (i.e., the beam pair includes a transmit beam 121 of the aggressor gNB 104A, and a receive beam 131 of the victim gNB 104B).

[0070] In one embodiment, the victim gNB 104B may determine or identify if any of its receive beam(s) that are subject to CLI are going to be active in the near future. The victim gNB 104B may then report, to the aggressor gNB 104A, which of the identified receive beams are going to be used in the near future (e.g., next slots, frames, etc.).

[0071] In another embodiment, the aggressor gNB 104A may determine or identify if any of its transmit beam(s) that cause CLI are going to be active in the near future. The aggressor gNB 104A may then report, to the victim gNB 104B, which of the identified transmit beams are going to be used in the near future (e.g., next slots, frames, etc.).

[0072] The gNB that receives the reported information may then assess its own intended beams to verify whether there is a problem, or whether collision can be avoided by time domain scheduling, for example. A collision (or beam collision) may occur when the aggressor gNB 104A and victim gNB 104B select a pair of transmit and receive beams that are problematic from CLI perspective (according to the measurements).

[0073] If it is not possible to avoid the CLI in this way, the gNB that receives the reported information may propose one or more CLI mitigation schemes, such as beam-specific downlink transmit power reduction, orthogonal frequency separation, etc., to the other gNB.

[0074] This kind of spatial coordination between the aggressor gNB 104A and the victim gNB 104B may provide significant benefits in terms of the gNB-to-gNB CLI mitigation.

[0075] The spatial coordination may occur only if a potential beam collision is identified. This is in contrast with solutions where prohibited and / or desired beams may be signaled and aggressor gNBs are expected to always mute the transmissions over certain transmit beams during CLI slots, regardless of the used receive beam. CLI slots refer to slots with opposite link direction. This isknown among the gNBs because they may communicate such information over the Xn interface with the intendedTDDConfiguration information element.

[0076] Furthermore, inter-cell UE-to-UE CL1 that would occur due to close UE proximity (e.g., see the UEs 100, 102 in FIG. IB) may be reduced as a result of the spatial coordination between the gNBs 104A, 104B.

[0077] FIG. 2 illustrates a signal flow diagram according to an example embodiment, wherein the aggressor indicates the intended beam(s), and the collision is evaluated by the victim.

[0078] Referring to FIG. 2, at 201, a first network entity 104A transmits, to a second network entity 104B, a resource configuration indicating one or more resources to be used for measuring cross-link interference between the first network entity 104A and the second network entity 104B. The second network entity 104B receives the resource configuration. For example, the first network entity 104A may indicate the channel state information reference signal (CS1-RS) resources that it has configured, and the second network entity 104B may then use this information to configure measurement resources to measure the CL1. These measurement resources may overlap with the CS1-RS resources used at the first network entity 104A for CS1-RS transmissions.

[0079] As an example, the first network entity 104A may indicate that CS1-RS config#0 occurs in slots 1, 3, 5, 7, occupies certain resource blocks, etc. This CS1-RS config#0 has index 0 and corresponds to transmit beam 0 of the first network entity 104A.

[0080] As another example, CS1-RS config# 1 may occur in slots 2, 4, 6, 8, occupy certain resource blocks, etc. This CS1-RS config# 1 has index 1 and corresponds to transmit beam 1 of the first network entity 104A.

[0081] With this information, the second network entity 104B may configure the gNB-to-gNB CL1 measurement resource(s), such that they overlap with the CS1-RS configuration(s).

[0082] Herein the terms 'first network entity’ and 'second network entity’ are used to distinguish the network entities, and they do not necessarily mean a specific order or specific identifiers of the network entities. For example,the first network entity may refer to the aggressor gNB 104A of FIG. IB, and the second network entity may refer to the victim gNB 104B of FIG. IB. Alternatively, the first network entity and the second network entity may be UEs 100, 102.

[0083] At 202, the first network entity 104A transmits, to the second network entity 104B, a configuration for a cross-link interference measurement report. The second network entity 104B receives the configuration for the crosslink interference measurement report. The configurations of 201 and 202 may be separate, or they may be included in the same configuration.

[0084] The configuration for the cross-link interference measurement report may indicate at least one of: a number of transmit beams of the first network entity 104A with the strongest measured cross-link interference (and their corresponding receive beams) to be included in a list of beams to be reported to the first network entity 104A; or a cross-link interference power threshold, wherein the transmit beams of the first network entity 104A with CLI above the cross-link interference power threshold (and their corresponding receive beams) are to be reported to the first network entity 104A. Alternatively, the configuration for the cross-link interference measurement report may indicate to report the complete CLI measurement table with the identifiers of all of the transmit beams and the receive beams, and their corresponding CLI measurements.

[0085] At 203, the second network entity 104B performs, based on the configuration of 201 and / or 202, the measurement of the cross-link interference on the one or more resources for one or more beam pairs associated with the first network entity 104A and the second network entity 104B. The second network entity 104B may individually measure the CLI at each measurement resource for each of its receive beams.

[0086] At 204, the second network entity 104B, generates, based on the measurement, a table (or list, information, etc.) comprising a cross-link interference value measured per beam pair of the one or more beam pairs. A given beam pair may comprise a transmit (Tx) beam 121, 122, 123, 124, 125 of the first network entity 104A, and areceive (Rx) beam 131, 132, 133, 134, 135 ofthe second network entity 104B.

[0087] A non-limiting example of the table is presented in Table 1 below, which includes the measured absolute power of the cross-link interference in decibel-milliwatts (dBm) for each Rx beam of the of the second network entity 104B from each Tx beam of the first network entity 104A. In Table 1, the strongest CL1 (-76 dBm) is experienced by Rx beam 1 in combination with Tx beam 0. Thus, it would be beneficial to avoid using Tx beam 0 and Rx beam 1 at the same time. However, Tx beam 0 can still be used at the same time with Rx beams 0, 2, and 3, since the CL1 is not as significant with these beam combinations.Table 1

[0088] The second network entity 104B knows about the transmit beams of the first network entity 104A based on the resource configuration shared by the first network entity 104A at 201. The transmit beams and receive beam can be identified by the reference signal resource identifier (e.g., CS1-RS resource ID or SSB index). For example, the second network entity 104B may associate each CL1 measurement with the corresponding CS1-RS index (which represents a transmit beam of the first network entity 104A).

[0089] At 205, the second network entity 104B generates, based on the table of 203 and the configuration of 202, the cross-link interference measurement report indicating a result of the measurement for the one or more beam pairs associated with the first network entity 104A and the second network entity 104B.

[0090] The cross-link interference measurement report may comprise a list including at least one of: an identifier of at least a transmit beam of the first network entity 104A with the strongest measured cross-link interference and oneor more corresponding receive beams of the second network entity 104B (e.g., N most interfering Tx beams and their corresponding Rx beams, with N being a parameter preconfigured at 202); one or more identifiers of one or more transmit beams of the first network entity 104A with a measured cross-link interference power level above a cross-link interference power threshold and one or more corresponding receive beams of the second network entity 104B; or one or more cross-link interference values measured per beam pair of the one or more beam pairs on the one or more resources, the one or more beam pairs comprising a transmit beam of the first network entity 104A and a receive beam of the second network entity 104B, respectively.

[0091] For example, referring to Table 1, if the second network entity 104B is pre-configured to include two transmit beams with the strongest measured CL1 in the list (N = 2), then the cross-link interference measurement report may comprise a list including Tx beam 0 paired with Rx beam 1, as well as Tx beam 1 paired with Rx beam 0, since these beam pairs experienced the strongest CL1 (-76 dBm and -85 dBm, respectively).

[0092] As another example, referring to Table 1, if the second network entity 104B is pre-configured with a cross-link interference power threshold value of -100 dBm, then the cross-link interference measurement report may indicate Tx beam 0 paired with Rx beam 1, as well as Tx beam 1 paired with Rx beams 0 and 2, since the CL1 measured for these beam pairs is above -100 dBm.

[0093] The cross-link interference measurement report may further indicate a ratio of lowest received intended uplink signal power and a measured cross-link interference power level per receive beam 131, 132, 133, 134, 135 ofthe second network entity 104B. This ratio indicates the tolerance of the second network entity 104B to the cross-link interference per receive beam of the second network entity 104B. This may be useful, for example, in cases where the absolute CL1 power level is relatively low but the impact on a cell-edge UE can be significant, or the absolute CL1 power level is considerably high but the impact on the UL reception is marginal due to high UL signal power. To inform about the worst CL1 conditions for each beam, the second network entity 104B may use the lowestreceived UL signal power to obtain this ratio.

[0094] At 206, the second network entity 104B transmits the cross-link interference measurement report to the first network entity 104A. The first network entity 104A receives the cross-link interference measurement report.

[0095] Signaling the identifiers of both the transmit beam(s) and the receive beam(s) allow the first network entity 104A, due to reciprocity, to automatically know the beam pairs that receive higher CL1, in case the roles of the first network entity 104A and the second network entity 104B are changed or reversed in the future (e.g., the first network entity 104A becomes the victim, and the second network entity 104B becomes the aggressor).

[0096] At 207, the first network entity 104A determines or identifies, based on the cross-link interference measurement report, at least one beam (transmit or receive beam) intended to be used by the first network entity 104A in at least one time interval (e.g., slot or symbol). In other words, the first network entity 104A may identify if any of the reported beam(s) are currently active and / or are expected to be active in the near future.

[0097] For example, at least one of the following can be used to determine which transmit beams will be used for DL transmissions in DL or SBFD slots: semi-persistent DL transmissions, or periodic signals such as SSB, periodic CS1-RS, etc.

[0098] For example, at least one of the following can be used to determine which receive beams will be used for UL reception in UL or SBFD slots: periodic sounding reference signal (SRS) or physical uplink control channel (PUCCH) transmissions, configured grant physical uplink shared channel (PUSCH), last receive beam used for PUSCH reception of UEs with high last reported buffer status report (BSR), beam-load information (e.g., by identifying the beams with the most assigned UEs having the strictest Quality of Service requirements to determine in which UL beams the victim gNB is most likely to schedule UEs for UL transmissions), or receive beams more robust to self-interference during SBFD slots.

[0099] At 208, the first network entity 104A transmits, to the secondnetwork entity 104B, an indication indicating the at least one beam intended to be used by the first network entity 104A in the at least one time interval. In other words, this indication may indicate when the at least one beam is intended to be used by the first network entity 104A. The second network entity 104B receives the indication.

[0100] In this way, when the first network entity 104A intends to schedule UL or DL on one or more beams identified in the cross-link interference measurement report, the first network entity 104A indicates this to the second network entity 104B. As an example, this beam scheduling information may be included in the “Intended TDD DL-UL Configuration” information element (IE) defined in TS 38.423, as shown in Table 2 below. The intended Rx beam(s) index and / or the intended Tx beam(s) index may be used at the slot(s) (time interval) indicated by the slot configuration list. In Table 2, the symbol “>” is used before each row. This symbol is used to indicate the hierarchy of each parameter. The intended Tx / Rx beams index parameter has “>»”, while the slot index parameter has “»”. This may mean that each slot index has its own Tx / Rx beam index.

[0101] The time granularity of this information exchange is, at least, the same as the decision of how to turn the flexible slot into DL or UL. In other cases, the network entities 104A, 104B can also exchange this information more frequently, for example as needed based on the intended beam usage.Table 2

[0102] At 209, the second network entity 104B determines, based on the indication and the cross-link interference measurement report, whether the at least one beam intended to be used by the first network entity 104A in the at least one time interval is expected to interfere with at least one beam intended to be used by the second network entity 104B in the at least one time interval.

[0103] In other words, the second network entity 104B evaluates whether a beam collision is expected to happen in the near future. A beam collision occurs when the intended transmit beam of the aggressor and the intended receive beam of the victim results in strong CL1. For example, referring to Table 1 above, strong CL1 may occur if Tx beam 1 and Rx beam 0 are used during the same time slot.

[0104] The at least one beam intended to be used by the first network entity 104A may comprise at least one transmit beam of the one or more beam pairs, and the at least one beam intended to be used by the second network entity 104B may comprise at least one receive beam of the one or more beam pairs.

[0105] Alternatively, in case the roles of the aggressor and the victim are reversed (e.g., at or after 206), the at least one beam intended to be used by the first network entity 104A may comprise at least one receive beam of the one or more beam pairs, and the at least one beam intended to be used by the second network entity 104B may comprise at least one transmit beam of the one or more beam pairs. When the roles are reversed, the beam identifiers or spatial filters orangles may be reversed, such that the transmit beams of the first network entity 104A become receive beams, and the receive beams of the second network entity 104B become transmit beams.

[0106] The second network entity 104B may transmit or receive data in the at least one time interval using the at least one beam intended to be used by the second network entity, if the at least one beam intended to be used by the first network entity 104A is not expected to interfere with the at least one beam intended to be used by the second network entity 104B. In other words, if beam collision is not expected, the victim and the aggressor can receive and transmit on their respective beams without any CL1 or with negligible CL1.

[0107] Alternatively, the second network entity 104B may re-schedule a transmission or a reception on the at least one beam intended to be used by the second network entity 104B to another time interval where the cross-link interference power is expected to be lower than in the at least one time interval according to the cross-link interference measurement report, if the at least one beam intended to be used by the first network entity 104A is expected to interfere with the at least one beam intended to be used by the second network entity 104B. For example, the second network entity 104B may re-schedule the intended UL for reception to a symbol or slot where the CL1 is more manageable or it is not expected at all. The network entities 104A, 104B may have a common slot type during the frame (e.g., the first DL slot and the last UL slot of the frame may be assumed to be fixed and synchronized across the network).

[0108] At 210, based on the determination of 209, the second network entity 104B transmits, to the first network entity 104A, an indication indicating whether the at least one beam intended to be used by the first network entity 104A is expected to interfere with at least one beam intended to be used by the second network entity 104B in the at least one time interval. The first network entity 104A receives the indication.

[0109] If the beams are expected to interfere and it is not possible to re-schedule the transmission or reception, the second network entity 104B may transmit, to the first network entity 104A, information indicating one or moremitigation techniques for mitigating cross-link interference between the at least one beam intended to be used by the first network entity 104A and the at least one beam intended to be used by the second network entity 104B.

[0110] In other words, if the beam collision cannot be avoided with rescheduling, the second network entity 104B may propose, to the first network entity 104A, one or more mitigation techniques for handling the CL1.

[0111] For example, the one or more mitigation techniques may comprise downlink transmit power reduction by a certain amount.

[0112] Alternatively, or additionally, the one or more mitigation techniques may comprise orthogonal frequency coordination using a previously configured (and agreed between the network entities 104A, 104B) frequency split separation for slots with cross-link interference.

[0113] Alternatively, or additionally, the one or more mitigation techniques may comprise forcing the aggressor (e.g., the first network entity 104A) to use Rank-1 transmission (or at least low rank) only on the colliding beam(s). This may be useful, as the victim (e.g., the second network entity 104B) can combat the CL1 more easily with low rank. This is the case for both linear interference suppression receivers such as minimum mean-squared error interference rejection combining (MMSE-1RC), and non-linear interference cancellation such as successive interference cancellation (SIC).

[0114] At 211, the first network entity 104A may apply the one or more mitigation techniques for mitigating the cross-link interference. In this way, the first network entity 104A and the second network entity 104B may coordinate with each other based on the cross-link interference measurement report for mitigating the cross-link interference.

[0115] If the CL1 mitigation scheme is configured to use orthogonal resources in frequency, then the second network entity 104B may also apply the one or more mitigation techniques.

[0116] FIG. 3 illustrates a signal flow diagram according to an example embodiment, wherein the victim indicates the intended beam(s), and the collision is evaluated by the aggressor.

[0117] Referring to FIG. 3, at 301, a first network entity 104A transmits, to a second network entity 104B, a resource configuration indicating one or more resources to be used for measuring cross-link interference between the first network entity 104A and the second network entity 104B. The second network entity 104B receives the resource configuration. For example, the first network entity 104A may indicate the CSI-RS resources that it has configured, and the second network entity 104B may then use this information to configure measurement resources to measure the CLI. These measurement resources may overlap with the CSI-RS resources used at the first network entity 104A for CSI-RS transmissions.

[0118] As an example, the first network entity 104A may indicate that CSI-RS config#0 occurs in slots 1, 3, 5, 7, occupies certain resource blocks, etc. This CSI-RS config#0 has index 0 and corresponds to transmit beam 0 of the first network entity 104A.

[0119] As another example, CSI-RS config# 1 may occur in slots 2, 4, 6, 8, occupy certain resource blocks, etc. This CSI-RS config# 1 has index 1 and corresponds to transmit beam 1 of the first network entity 104A.

[0120] With this information, the second network entity 104B may configure the gNB-to-gNB CLI measurement resource(s), such that they overlap with the CSI-RS configuration(s).

[0121] Herein the terms 'first network entity’ and 'second network entity’ are used to distinguish the network entities, and they do not necessarily mean a specific order or specific identifiers of the network entities. For example, the first network entity may refer to the aggressor gNB 104A of FIG. IB, and the second network entity may refer to the victim gNB 104B of FIG. IB. Alternatively, the first network entity and the second network entity may be UEs 100, 102.

[0122] At 302, the first network entity 104A transmits, to the second network entity 104B, a configuration for a cross-link interference measurement report. The second network entity 104B receives the configuration for the crosslink interference measurement report. The configurations of 301 and 302 may be separate, or they may be included in the same configuration.

[0123] The configuration for the cross-link interference measurement report may indicate at least one of: a number of transmit beams of the first network entity 104A with the strongest measured cross-link interference (and their corresponding receive beams) to be included in a list of beams to be reported to the first network entity 104A; or a cross-link interference power threshold, wherein the transmit beams of the first network entity 104A with CL1 power above the cross-link interference power threshold (and their corresponding receive beams) are to be reported to the first network entity 104A. Alternatively, the configuration for the cross-link interference measurement report may indicate to report the complete CL1 measurement table with the identifiers of all of the transmit beams and the receive beams, and their corresponding CL1 measurements.

[0124] At 303, the second network entity 104B performs, based on the configuration of 301 and / or 302, the measurement of the cross-link interference on the one or more resources for one or more beam pairs associated with the first network entity 104A and the second network entity 104B. The second network entity 104B may individually measure the CL1 at each measurement resource for each of its receive beams.

[0125] At 304, the second network entity 104B, generates, based on the measurement, a table (or list, information, etc.) comprising a cross-link interference value measured per beam pair of the one or more beam pairs. A given beam pair comprises a transmit (Tx) beam 121, 122, 123, 124, 125 of the first network entity 104A, and a receive (Rx) beam 131, 132, 133, 134, 135 of the second network entity 104B. A non-limiting example of the table is presented in Table 1 above.

[0126] The second network entity 104B knows about the transmit beams of the first network entity 104A based on the resource configuration shared by the first network entity 104A at 301. The transmit beams and receive beam can be identified by the reference signal resource identifier (e.g., CS1-RS resource ID or SSB index). For example, the second network entity 104B may associate each CL1 measurement with the corresponding CS1-RS index (which represents a transmitbeam of the first network entity 104A).

[0127] At 305, the second network entity 104B generates, based on the table of 303 and the configuration of 302, the cross-link interference measurement report indicating a result of the measurement for the one or more beam pairs associated with the first network entity 104A and the second network entity 104B.

[0128] The cross-link interference measurement report may comprise a list including at least one of: an identifier of at least a transmit beam of the first network entity 104A with the strongest measured cross-link interference and one or more corresponding receive beams of the second network entity 104B (e.g., N most interfering Tx beams and their corresponding Rx beams, with N being a parameter preconfigured at 302); one or more identifiers of one or more transmit beams of the first network entity 104A with a measured cross-link interference power level above a cross-link interference power threshold and one or more corresponding receive beams of the second network entity 104B; or one or more cross-link interference values measured per beam pair of the one or more beam pairs on the one or more resources, the one or more beam pairs comprising a transmit beam of the first network entity 104A and a receive beam of the second network entity 104B, respectively.

[0129] The cross-link interference measurement report may further indicate a ratio of lowest received intended uplink signal power and a measured cross-link interference power level per receive beam 131, 132, 133, 134, 135 of the second network entity 104B. This ratio indicates the tolerance of the second network entity 104B to the cross-link interference per receive beam of the second network entity 104B. This may be useful, for example, in cases where the absolute CL1 level is relatively low but the impact on a cell-edge UE can be significant, or the absolute CL1 level is considerably high but the impact on the UL reception is marginal due to high UL signal power. To inform about the worst CL1 conditions for each beam, the second network entity 104B may use the lowest received UL signal power to obtain this ratio.

[0130] At 306, the second network entity 104B transmits the cross-link interference measurement report to the first network entity 104A. The firstnetwork entity 104A receives the cross-link interference measurement report.

[0131] Signaling the identifiers of both the transmit beam(s) and the receive beam(s) allow the first network entity 104A, due to reciprocity, to automatically know the beam pairs that receive higher CL1, in case the roles of the first network entity 104A and the second network entity 104B are changed or reversed in the future (e.g., the first network entity 104A becomes the victim, and the second network entity 104B becomes the aggressor).

[0132] At 307, the second network entity 104B determines or identifies, based on the cross-link interference measurement report, at least one beam (transmit or receive beam) intended to be used by the second network entity 104B in at least one time interval (e.g., slot or symbol). In other words, the second network entity 104B may identify if any of the reported beam(s) are currently active and / or are expected to be active in the near future.

[0133] For example, at least one of the following can be used to determine which transmit beams will be used for DL transmission in DL or SBFD slots: semi-persistent DL transmissions, or periodic signals such as SSB, periodic CS1-RS, etc.

[0134] For example, at least one of the following can be used to determine which receive beams will be used for UL reception in UL or SBFD slots: periodic sounding reference signal (SRS) or physical uplink control channel (PUCCH) transmissions, configured grant physical uplink shared channel (PUSCH), last receive beam used for PUSCH reception of UEs with high last reported buffer status report (BSR), beam-load information (e.g., by identifying the beams with the most assigned UEs having the strictest Quality of Service requirements to determine in which UL beams the victim gNB is most likely to schedule UEs for UL transmissions), or receive beams more robust to self-interference during SBFD slots.

[0135] At 308, the second network entity 104B transmits, to the first network entity 104A, an indication indicating the at least one beam intended to be used by the second network entity 104B in the at least one time interval. In other words, this indication may indicate when the at least one beam is intended to beused by the second network entity 104B. The first network entity 104A receives the indication.

[0136] In this way, when the second network entity 104B intends to schedule UL or DL on one or more beams identified in the cross-link interference measurement report, the second network entity 104B indicates this to the first network entity 104A. As an example, this beam scheduling information may be included in the “Intended TDD DL-UL Configuration” information element (IE) defined in TS 38.423, as shown in Table 2 above. The time granularity of this information exchange is, at least, the same as the decision of how to turn the flexible slot into DL or UL. In other cases, the network entities 104A, 104B can also exchange this information more frequently, for example as needed based on the intended beam usage.

[0137] At 309, the first network entity 104A determines, based on the indication and the cross-link interference measurement report, whether the at least one beam intended to be used by the second network entity 104B in the at least one time interval is expected to interfere with at least one beam intended to be used by the first network entity 104A in the at least one time interval.

[0138] In other words, the first network entity 104A evaluates whether a beam collision is expected to happen in the near future. A beam collision occurs when the intended transmit beam of the aggressor and the intended receive beam of the victim results in strong CLI. For example, referring to Table 1 above, strong CLI may occur if Tx beam 1 and Rx beam 0 are used during the same time slot.

[0139] The at least one beam intended to be used by the first network entity 104A may comprise at least one transmit beam of the one or more beam pairs, and the at least one beam intended to be used by the second network entity 104B may comprise at least one receive beam of the one or more beam pairs.

[0140] Alternatively, in case the roles of the aggressor and the victim are reversed (e.g., at or after 306), the at least one beam intended to be used by the first network entity 104A may comprise at least one receive beam of the one or more beam pairs, and the at least one beam intended to be used by the second network entity 104B may comprise at least one transmit beam of the one or morebeam pairs. When the roles are reversed, the beam identifiers or spatial filters or angles may be reversed, such that the transmit beams of the first network entity 104A become receive beams, and the receive beams of the second network entity 104B become transmit beams.

[0141] The first network entity 104A may transmit or receive data in the at least one time interval using the at least one beam intended to be used by the first network entity, if the at least one beam intended to be used by the first network entity 104A is not expected to interfere with the at least one beam intended to be used by the second network entity 104B. In other words, if beam collision is not expected, the victim and the aggressor can receive and transmit on their respective beams without any CL1 or with negligible CL1.

[0142] Alternatively, the first network entity 104A may re-schedule a transmission or a reception on the at least one beam intended to be used by the first network entity 104A to another time interval where the cross-link interference power is expected to be lower than in the at least one time interval according to the cross-link interference measurement report, if the at least one beam intended to be used by the first network entity 104A is expected to interfere with the at least one beam intended to be used by the second network entity 104B. For example, the first network entity 104A may re-schedule the intended UL for reception to a symbol or slot where the CL1 is more manageable or it is not expected at all. The network entities 104A, 104B may have a common slot type during the frame (e.g., the first DL slot and the last UL slot of the frame may be assumed to be fixed and synchronized across the network).

[0143] At 310, based on the determination of 309, the first network entity 104A transmits, to the second network entity 104B, an indication indicating whether the at least one beam intended to be used by the first network entity 104A is expected to interfere with at least one beam intended to be used by the second network entity 104B in the at least one time interval. The second network entity 104B receives the indication.

[0144] If the beams are expected to interfere and it is not possible to re-schedule the transmission or reception, the first network entity 104A maytransmit, to the second network entity 104B, information indicating one or more mitigation techniques for mitigating cross-link interference between the at least one beam intended to be used by the first network entity 104A and the at least one beam intended to be used by the second network entity 104B.

[0145] In other words, if the beam collision cannot be avoided with rescheduling, the first network entity 104A may propose, to the second network entity 104B, one or more mitigation techniques for handling the CL1.

[0146] For example, the one or more mitigation techniques may comprise downlink transmit power reduction by a certain amount.

[0147] Alternatively, or additionally, the one or more mitigation techniques may comprise orthogonal frequency coordination using a previously configured (and agreed between the network entities 104A, 104B) frequency split separation for slots with cross-link interference.

[0148] Alternatively, or additionally, the one or more mitigation techniques may comprise forcing the aggressor (e.g., the second network entity 104B) to use Rank-1 transmission (or at least low rank) only on the colliding beam(s). This may be useful, as the victim (e.g., the first network entity 104A) can combat the CL1 more easily with low rank. This is the case for both linear interference suppression receivers such as minimum mean-squared error interference rejection combining (MMSE-1RC), and non-linear interference cancellation such as successive interference cancellation (SIC).

[0149] At 311, the second network entity 104B may apply the one or more mitigation techniques for mitigating the cross-link interference. In this way, the first network entity 104A and the second network entity 104B may coordinate with each other based on the cross-link interference measurement report for mitigating the cross-link interference.

[0150] If the CL1 mitigation scheme is configured to use orthogonal resources in frequency, then the first network entity 104A may also apply the one or more mitigation techniques.

[0151] FIG. 4 illustrates a flow chart according to an example embodiment of a method performed by an apparatus 700 (depicted in FIG. 7) of afirst network entity 104A, 100.

[0152] Referring to FIG. 4, in block 401, the apparatus 700 transmits, to a second network entity 104B, 102, a configuration indicating one or more resources to be used for measuring cross-link interference between the first network entity 104A, 100 and the second network entity 104B, 102.

[0153] The first network entity may comprise a first radio access network node 104A, and the second network entity may comprise a second radio access network node 104B different from the first radio access network node 104A.

[0154] Alternatively, the first network entity may comprise a first user equipment 100, and the second network entity may comprise a second user equipment 102 different from the first user equipment 100.

[0155] Herein the terms 'first network radio access network node’ and 'second radio access network node’ are used to distinguish the network nodes, and they do not necessarily mean a specific order or specific identifiers of the network nodes.

[0156] Similarly, the terms 'first user equipment and 'second user equipment’ are used to distinguish the UEs, and they do not necessarily mean a specific order or specific identifiers of the UEs.

[0157] In block 402, the apparatus 700 receives, from the second network entity 104B, 102, a cross-link interference measurement report indicating a result of the measurement for one or more beam pairs associated with the first network entity 104A, 100 and the second network entity 104B, 102.

[0158] In block 403, the apparatus 700 coordinates with the second network entity 104B, 102 based on the cross-link interference measurement report for mitigating the cross-link interference.

[0159] The cross-link interference measurement report may comprise a list including at least one of: an identifier of at least a transmit beam of the first network entity with the strongest measured cross-link interference and one or more corresponding receive beams of the second network entity; one or more identifiers of one or more transmit beams of the first network entity with a measured cross-link interference power level above a cross-link interferencepower threshold and one or more corresponding receive beams of the second network entity; or one or more cross-link interference values measured per beam pair of the one or more beam pairs on the one or more resources, the one or more beam pairs comprising a transmit beam of the first network entity and a receive beam of the second network entity, respectively.

[0160] The cross-link interference measurement report may further indicate a ratio of lowest received intended uplink signal power and a measured cross-link interference power level per receive beam of the second network entity.

[0161] Prior to receiving the cross-link interference report, the apparatus 700 may transmit, to the second network entity, a configuration indicating at least one of: a number of transmit beams of the first network entity to be included in the list; or the cross-link interference power threshold. For example, if the number of transmit beams to be included in the list is three, then the list may include an identifier of the transmit beam with the highest measured CL1 and an identifier of the corresponding receive beam, an identifier of the transmit beam with the second-highest measured CL1 and an identifier of the corresponding receive beam, and an identifier of the transmit beam with the third-highest CL1 and the corresponding receive beam.

[0162] As an example, the coordination may comprise at least: transmitting, to the second network entity, an indication indicating at least one beam intended to be used by the first network entity in at least one time interval; and receiving, from the second network entity, an indication indicating whether the at least one beam intended to be used by the first network entity is expected to interfere with at least one beam intended to be used by the second network entity in the at least one time interval.

[0163] As another example, the coordination may comprise at least: receiving, from the second network entity, an indication indicating at least one beam intended to be used by the second network entity in at least one time interval; determining, based on the indication and the cross-link interference measurement report, whether at least one beam intended to be used by the first network entity in the at least one time interval is expected to interfere with the at least one beamintended to be used by the second network entity in the at least one time interval; and transmitting, to the second network entity, based on the determination, an indication indicating whether the at least one beam intended to be used by the first network entity in the at least one time interval is expected to interfere with the at least one beam intended to be used by the second network entity in the at least one time interval.

[0164] The at least one beam intended to be used by the first network entity may comprise at least one transmit beam of the one or more beam pairs, and the at least one beam intended to be used by the second network entity may comprise at least one receive beam of the one or more beam pairs.

[0165] Alternatively, the at least one beam intended to be used by the first network entity may comprise at least one receive beam of the one or more beam pairs, and the at least one beam intended to be used by the second network entity may comprise at least one transmit beam of the one or more beam pairs.

[0166] The apparatus 700 may transmit or receive data in the at least one time interval using the at least one beam intended to be used by the first network entity, based on the at least one beam intended to be used by the first network entity not being expected to interfere with the at least one beam intended to be used by the second network entity.

[0167] Alternatively, the apparatus 700 may re-schedule a transmission or a reception on the at least one beam intended to be used by the first network entity to another time interval where the cross-link interference is expected to be lower than in the at least one time interval according to the crosslink interference measurement report, based on the at least one beam intended to be used by the first network entity being expected to interfere with the at least one beam intended to be used by the second network entity.

[0168] Alternatively, the apparatus 700 may transmit, to the second network entity, information indicating one or more mitigation techniques for mitigating cross-link interference between the at least one beam intended to be used by the first network entity and the at least one beam intended to be used by the second network entity, based on the at least one beam intended to be used bythe first network entity being expected to interfere with the at least one beam intended to be used by the second network entity.

[0169] Alternatively, the apparatus 700 may receive, from the second network entity, information indicating one or more mitigation techniques for mitigating cross-link interference between the at least one beam intended to be used by the first network entity and the at least one beam intended to be used by the second network entity; and apply the one or more mitigation techniques.

[0170] FIG. 5 illustrates a flow chart according to an example embodiment of a method performed by an apparatus 700 (depicted in FIG. 7) of a second network entity 104B, 102.

[0171] Referring to FIG. 5, in block 501, the apparatus 700 receives, from a first network entity 104A, 100, a configuration indicating one or more resources to be used for measuring cross-link interference between the first network entity 104A, 100 and the second network entity 104B, 102.

[0172] The first network entity may comprise a first radio access network node 104A, and the second network entity may comprise a second radio access network node 104B different from the first radio access network node 104A.

[0173] Alternatively, the first network entity may comprise a first user equipment 100, and the second network entity may comprise a second user equipment 102 different from the first user equipment 100.

[0174] Herein the terms 'first network radio access network node’ and 'second radio access network node’ are used to distinguish the network nodes, and they do not necessarily mean a specific order or specific identifiers of the network nodes.

[0175] Similarly, the terms 'first user equipment and 'second user equipment’ are used to distinguish the UEs, and they do not necessarily mean a specific order or specific identifiers of the UEs.

[0176] In block 502, the apparatus 700 performs, based on the configuration, the measurement of the cross-link interference on the one or more resources for one or more beam pairs associated with the first network entity 104A, 100 and the second network entity 104B, 102.

[0177] The apparatus 700 may generate, based on the measurement, a table comprising a cross-link interference value measured per beam pair of the one or more beam pairs.

[0178] The apparatus 700 may generate a cross-link interference measurement report based on the table.

[0179] In block 503, the apparatus 700 transmits, to the first network entity 104A, 100, the cross-link interference measurement report indicating a result of the measurement for the one or more beam pairs associated with the first network entity 104A, 100 and the second network entity 104B, 102.

[0180] In block 504, the apparatus 700 coordinates with the first network entity 104A, 100 based on the cross-link interference measurement report for mitigating the cross-link interference.

[0181] The cross-link interference measurement report may comprise a list including at least one of: an identifier of at least a transmit beam of the first network entity with the strongest measured cross-link interference and one or more corresponding receive beams of the second network entity; one or more identifiers of one or more transmit beams of the first network entity with a measured cross-link interference power level above a cross-link interference power threshold and one or more corresponding receive beams of the second network entity; or one or more cross-link interference values measured per beam pair of the one or more beam pairs on the one or more resources, the one or more beam pairs comprising a transmit beam of the first network entity and a receive beam of the second network entity, respectively.

[0182] The cross-link interference measurement report may further indicate a ratio of lowest received intended uplink signal power and a measured cross-link interference power level per receive beam of the second network entity.

[0183] Prior to transmitting the cross-link interference measurement report, the apparatus 700 may receive, from the first network entity, a configuration indicating at least one of: a number of transmit beams of the first network entity to be included in the list; or the cross-link interference power threshold.

[0184] As an example, the coordination may comprise at least: receiving, from the first network entity, an indication indicating at least one beam intended to be used by the first network entity in at least one time interval; determining, based on the indication and the cross-link interference measurement report, whether the at least one beam intended to be used by the first network entity is expected to interfere with at least one beam intended to be used by the second network entity in the at least one time interval; and transmitting, to the first network entity, based on the determination, an indication indicating whether the at least one beam intended to be used by the first network entity is expected to interfere with at least one beam intended to be used by the second network entity in the at least one time interval.

[0185] As another example, the coordination may comprise at least: transmitting, to the first network entity, an indication indicating at least one beam intended to be used by the second network entity in at least one time interval; and receiving, from the first network entity, an indication indicating whether at least one beam intended to be used by the first network entity in the at least one time interval is expected to interfere with the at least one beam intended to be used by the second network entity in the at least one time interval.

[0186] The at least one beam intended to be used by the first network entity may comprise at least one transmit beam of the one or more beam pairs, and the at least one beam intended to be used by the second network entity may comprise at least one receive beam of the one or more beam pairs; or

[0187] Alternatively, the at least one beam intended to be used by the first network entity may comprise at least one receive beam of the one or more beam pairs, and the at least one beam intended to be used by the second network entity may comprise at least one transmit beam of the one or more beam pairs.

[0188] The apparatus 700 may transmit or receive data in the at least one time interval using the at least one beam intended to be used by the second network entity, based on the at least one beam intended to be used by the first network entity not being expected to interfere with the at least one beam intended to be used by the second network entity.

[0189] Alternatively, the apparatus 700 may re-schedule a transmission or a reception on the at least one beam intended to be used by the second network entity to another time interval where the cross-link interference is expected to be lower than in the at least one time interval according to the crosslink interference measurement report, based on the at least one beam intended to be used by the first network entity being expected to interfere with the at least one beam intended to be used by the second network entity.

[0190] Alternatively, the apparatus 700 may receive, from the first network entity, information indicating one or more mitigation techniques for mitigating cross-link interference between the at least one beam intended to be used by the first network entity and the at least one beam intended to be used by the second network entity; and apply the one or more mitigation techniques.

[0191] Alternatively, the apparatus 700 may transmit, to the first network entity, information indicating one or more mitigation techniques for mitigating cross-link interference between the at least one beam intended to be used by the first network entity and the at least one beam intended to be used by the second network entity, based on the at least one beam intended to be used by the first network entity being expected to interfere with the at least one beam intended to be used by the second network entity.

[0192] FIG. 6 illustrates a flow chart according to an example embodiment of a method performed by an apparatus 700 (depicted in FIG. 7) of a first network entity or a second network entity.

[0193] The method shown in FIG. 6 may be performed, for example, in block 403 of FIG. 4 or block 504 of FIG. 5.

[0194] Referring to FIG. 6, in block 601, the apparatus 700 receives, from another network entity, an indication indicating at least one beam intended to be used by the other network entity in at least one time interval. In case the apparatus 700 is the first network entity 104A, 100, then the other network entity may refer to the second network entity 104B, 102. In case the apparatus 700 is the second network entity 104B, 102, then the other network entity may refer to the first network entity 104A, 100.

[0195] In block 602, the apparatus 700 determines, based on the indication and the cross-link interference measurement report, whether at least one beam intended to be used by the apparatus 700 in the at least one time interval is expected to interfere with the at least one beam intended to be used by the other network entity in the at least one time interval.

[0196] The at least one beam intended to be used by the apparatus 700 may comprise at least one transmit beam of the one or more beam pairs, and the at least one beam intended to be used by the other network entity may comprise at least one receive beam of the one or more beam pairs.

[0197] Alternatively, the at least one beam intended to be used by the apparatus 700 may comprise at least one receive beam of the one or more beam pairs, and the at least one beam intended to be used by the other network entity may comprise at least one transmit beam of the one or more beam pairs.

[0198] In block 603, based on the at least one beam intended to be used by apparatus 700 not being expected to interfere with the at least one beam intended to be used by the other network entity (block 602: no), the apparatus 700 may transmit or receive data in the at least one time interval using the at least one beam intended to be used by the apparatus 700.

[0199] In block 604, based on the at least one beam intended to be used by apparatus 700 being expected to interfere with the at least one beam intended to be used by the other network entity (block 602: yes), the apparatus 700 may determine whether the interference can be avoided by re-scheduling.

[0200] In block 605, based on the at least one beam intended to be used by the apparatus 700 being expected to interfere with the at least one beam intended to be used by the other network entity (block 602: yes), and based on determining that the interference can be avoided by re-scheduling (block 603: yes), the apparatus 700 re-schedules a transmission or a reception on the at least one beam intended to be used by the apparatus 700 to another time interval where the cross-link interference is expected to be lower than in the at least one time interval according to the cross-link interference measurement report.

[0201] In block 606, based on the at least one beam intended to be used by the apparatus 700 being expected to interfere with the at least one beam intended to be used by the other network entity (block 602: yes), and based on determining that the interference cannot be avoided by re-scheduling (block 603: no), the apparatus 700 transmits, to the other network entity, an indication indicating that the at least one beam intended to be used by the apparatus 700 is expected to interfere with the at least one beam intended to be used by the other network entity in the at least one time interval. The transmitted indication may comprise information indicating one or more mitigation techniques for mitigating the cross-link interference.

[0202] The blocks, related functions, and information exchanges (messages) described above by means of FIG. 2 to FIG. 6 are in no absolute chronological order, and some of them may be performed simultaneously or in an order differing from the described one. Other functions can also be executed between them or within them, and other information may be sent, and / or other rules applied. Some of the blocks or part of the blocks or one or more pieces of information can also be left out or replaced by a corresponding block or part of the block or one or more pieces of information.

[0203] As used herein, “at least one of the following: ” and “at least one of ” and similar wording, where the list of two or more elements are joined by “and” or “or”, mean at least any one of the elements, or at least any two or more of the elements, or at least all the elements.

[0204] FIG. 7 illustrates an example of an apparatus 700 of a first network entity or a second network entity, the apparatus 700 comprising means for performing one or more of the example embodiments described above with reference to FIGS. 2-6. For example, the apparatus 700 may be an apparatus such as, or comprising, or comprised in, a radio access network node 104, 104A, 104B. Alternatively, the apparatus 700 may be an apparatus such as, or comprising, or comprised in, a user equipment 100, 102.

[0205] The apparatus 700 may comprise, for example, a circuitry or achipset applicable for realizing one or more of the example embodiments described above. The apparatus 700 may be an electronic device comprising one or more electronic circuitries. The apparatus 700 may comprise a communication control circuitry 710 such as at least one processor, and at least one memory 720 storing instructions 722 which, when executed by the at least one processor, cause the apparatus 700 to carry out one or more of the example embodiments described above. Such instructions 722 may, for example, include computer program code (software). The at least one processor and the at least one memory storing the instructions may provide the means for providing or causing the performance of any of the methods and / or blocks described above.

[0206] The processor is coupled to the memory 720. The processor is configured to read and write data to and from the memory 720. The memory 720 may comprise one or more memory units. The memory units may be volatile or non-volatile. It is to be noted that there may be one or more units of non-volatile memory and one or more units of volatile memory or, alternatively, one or more units of non-volatile memory, or, alternatively, one or more units of volatile memory. Volatile memory may be for example random-access memory (RAM), dynamic random-access memory (DRAM) or synchronous dynamic random-access memory (SDRAM). Non-volatile memory may be for example read-only memory (ROM), programmable read-only memory (PROM), electronically erasable programmable read-only memory (EEPROM), flash memory, optical storage or magnetic storage. In general, memories may be referred to as non-transitory computer readable media. The term “non-transitory,” as used herein, is a limitation of the medium itself (i.e., tangible, not a signal) as opposed to a limitation on data storage persistency (e.g., RAM vs. ROM). The memory 720 stores computer readable instructions that are executed by the processor. For example, non-volatile memory stores the computer readable instructions, and the processor executes the instructions using volatile memory for temporary storage of data and / or instructions.

[0207] The computer readable instructions may have been pre-stored to the memory 720 or, alternatively or additionally, they may be received, by theapparatus, via an electromagnetic carrier signal and / or may be copied from a physical entity such as a computer program product. Execution of the computer readable instructions causes the apparatus 700 to perform one or more of the functionalities described above.

[0208] The memory 720 may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, flash memory, magnetic memory devices and systems, optical memory devices and systems, fixed memory and / or removable memory. The memory may comprise a configuration database for storing configuration data, such as a current neighbour cell list, and, in some example embodiments, structures of frames used in the detected neighbour cells.

[0209] The apparatus 700 may further comprise or be connected to a communication interface 730, such as a radio unit, comprising hardware and / or software for realizing communication connectivity with one or more wireless communication devices according to one or more communication protocols. The communication interface 730 comprises at least one transmitter (Tx) and at least one receiver (Rx) that may be integrated to the apparatus 700 or that the apparatus 700 may be connected to. The communication interface 730 may provide means for performing some of the blocks and / or functions (e.g., transmitting and receiving) for one or more example embodiments described above. The communication interface 730 may comprise one or more components, such as: power amplifier, digital front end (DFE), analog-to-digital converter (ADC), digital- to-analog converter (DAC), frequency converter, (de) modulator, and / or encoder / decoder circuitries, controlled by the corresponding controlling units.

[0210] The communication interface 730 provides the apparatus with radio communication capabilities to communicate in the wireless communication network. The communication interface may, for example, provide a radio interface to one or more UEs 100, 102. The apparatus 700 may further comprise or be connected to another interface towards the access node(s) 104, 104A, 104B of the wireless communication network.

[0211] In one example embodiment, the instructions 722, when executed by the control circuitry 710 (e.g., the at least one processor), may cause the apparatus 700 to: transmit, to a second network entity, via the communication interface 730, a configuration indicating one or more resources to be used for measuring cross-link interference between the first network entity and the second network entity; receive, from the second network entity, via the communication interface 730, a cross-link interference measurement report indicating a result of the measurement for one or more beam pairs associated with the first network entity and the second network entity; and coordinate with the second network entity, via the communication interface 730, based on the cross-link interference measurement report for mitigating the cross-link interference.

[0212] In another example embodiment, the instructions 722, when executed by the control circuitry 710 (e.g., the at least one processor), may cause the apparatus 700 to: receive, from a first network entity, via the communication interface 730, a configuration indicating one or more resources to be used for measuring cross-link interference between the first network entity and the second network entity; perform, based on the configuration, the measurement of the cross-link interference on the one or more resources for one or more beam pairs associated with the first network entity and the second network entity; transmit, to the first network entity, via the communication interface 730, a cross-link interference measurement report indicating a result of the measurement for the one or more beam pairs associated with the first network entity and the second network entity; and coordinate with the first network entity, via the communication interface 730, based on the cross-link interference measurement report for mitigating the cross-link interference.

[0213] It is to be noted that the apparatus 700 may further comprise various components not illustrated in FIG. 7. The various components may be hardware components and / or software components.

[0214] As used in this application, the term “circuitry” may refer to one or more or all of the following: a) hardware-only circuit implementations (such as implementations in only analog and / or digital circuitry); and b) combinations ofhardware circuits and software, such as (as applicable): i) a combination of analog and / or digital hardware circuit(s) with software / firmware and ii) any portions of hardware processor(s) with software (including digital signal processor(s), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone, to perform various functions); and c) hardware circuit(s) and / or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (for example firmware) for operation, but the software may not be present when it is not needed for operation.

[0215] This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and / or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.

[0216] The techniques and methods described herein may be implemented by various means. For example, these techniques may be implemented in hardware (one or more devices), firmware (one or more devices), software (one or more modules), or combinations thereof. For a hardware implementation, the apparatus(es) of example embodiments may be implemented within one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), graphics processing units (GPUs), processors, controllers, micro-controllers, microprocessors, other electronic units designed to perform the functions described herein, or a combination thereof. For firmware or software, the implementation can be carried out through modules of at least one chipset (for example procedures, functions, and so on) that perform the functions described herein. The software codes may be stored in a memory unit and executed by processors. The memory unit may beimplemented within the processor or externally to the processor. In the latter case, it can be communicatively coupled to the processor via various means, as is known in the art. Additionally, the components of the systems described herein may be rearranged and / or complemented by additional components in order to facilitate the achievements of the various aspects, etc., described with regard thereto, and they are not limited to the precise configurations set forth in the given figures, as will be appreciated by one skilled in the art.

[0217] It will be obvious to a person skilled in the art that, as technology advances, the inventive concept may be implemented in various ways within the scope of the claims. The embodiments are not limited to the example embodiments described above, but may vary within the scope of the claims. Therefore, all words and expressions should be interpreted broadly, and they are intended to illustrate, not to restrict, the embodiments.

Claims

Claims1. An apparatus of a first network entity, the apparatus comprising at least one processor, and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to: transmit, to a second network entity, a configuration indicating one or more resources to be used for measuring cross-link interference between the first network entity and the second network entity; receive, from the second network entity, a cross-link interference measurement report indicating a result of the measurement for one or more beam pairs associated with the first network entity and the second network entity; and coordinate with the second network entity based on the cross-link interference measurement report for mitigating the cross-link interference.

2. The apparatus according to claim 1, wherein the cross-link interference measurement report comprises a list including at least one of: an identifier of at least a transmit beam of the first network entity with the strongest measured cross-link interference and one or more corresponding receive beams of the second network entity; one or more identifiers of one or more transmit beams of the first network entity with a measured cross-link interference power level above a crosslink interference power threshold and one or more corresponding receive beams of the second network entity; or one or more cross-link interference values measured per beam pair of the one or more beam pairs on the one or more resources, the one or more beam pairs comprising a transmit beam of the first network entity and a receive beam of the second network entity, respectively.

3. The apparatus according to claim 2, further being caused to: transmit, to the second network entity, a configuration indicating at least one of:a number of transmit beams of the first network entity to be included in the list; or the cross-link interference power threshold.

4. The apparatus according to any of claims 2 to 3, wherein the crosslink interference measurement report further indicates a ratio of lowest received intended uplink signal power and a measured cross-link interference power level per receive beam of the second network entity.

5. The apparatus according to any preceding claim, wherein the coordination comprises at least: transmitting, to the second network entity, an indication indicating at least one beam intended to be used by the first network entity in at least one time interval; and receiving, from the second network entity, an indication indicating whether the at least one beam intended to be used by the first network entity is expected to interfere with at least one beam intended to be used by the second network entity in the at least one time interval, wherein the at least one beam intended to be used by the first network entity comprises at least one transmit beam of the one or more beam pairs, and the at least one beam intended to be used by the second network entity comprises at least one receive beam of the one or more beam pairs; or wherein the at least one beam intended to be used by the first network entity comprises at least one receive beam of the one or more beam pairs, and the at least one beam intended to be used by the second network entity comprises at least one transmit beam of the one or more beam pairs.

6. The apparatus according to any preceding claim, wherein the coordination comprises at least:receiving, from the second network entity, an indication indicating at least one beam intended to be used by the second network entity in at least one time interval; determining, based on the indication and the cross-link interference measurement report, whether at least one beam intended to be used by the first network entity in the at least one time interval is expected to interfere with the at least one beam intended to be used by the second network entity in the at least one time interval; and transmitting, to the second network entity, based on the determination, an indication indicating whether the at least one beam intended to be used by the first network entity in the at least one time interval is expected to interfere with the at least one beam intended to be used by the second network entity in the at least one time interval, wherein the at least one beam intended to be used by the first network entity comprises at least one transmit beam of the one or more beam pairs, and the at least one beam intended to be used by the second network entity comprises at least one receive beam of the one or more beam pairs; or wherein the at least one beam intended to be used by the first network entity comprises at least one receive beam of the one or more beam pairs, and the at least one beam intended to be used by the second network entity comprises at least one transmit beam of the one or more beam pairs.

7. The apparatus according to any of claims 5 to 6, further being caused to: transmit or receive data in the at least one time interval using the at least one beam intended to be used by the first network entity, based on the at least one beam intended to be used by the first network entity not being expected to interfere with the at least one beam intended to be used by the second network entity.

8. The apparatus according to any of claims 5 to 6, further being caused to: re-schedule a transmission or a reception on the at least one beam intended to be used by the first network entity to another time interval where the cross-link interference is expected to be lower than in the at least one time interval according to the cross-link interference measurement report, based on the at least one beam intended to be used by the first network entity being expected to interfere with the at least one beam intended to be used by the second network entity.

9. The apparatus according to any of claims 5 to 6, further being caused to: transmit, to the second network entity, information indicating one or more mitigation techniques for mitigating cross-link interference between the at least one beam intended to be used by the first network entity and the at least one beam intended to be used by the second network entity, based on the at least one beam intended to be used by the first network entity being expected to interfere with the at least one beam intended to be used by the second network entity.

10. The apparatus according to any of claims 5 to 6, further being caused to: receive, from the second network entity, information indicating one or more mitigation techniques for mitigating cross-link interference between the at least one beam intended to be used by the first network entity and the at least one beam intended to be used by the second network entity; and apply the one or more mitigation techniques.

11. The apparatus according to any preceding claim, wherein the first network entity comprises a first radio access network node; and wherein the second network entity comprises a second radio access network node different from the first radio access network node.

12. The apparatus according to any of claims 1 to 10, wherein the first network entity comprises a first user equipment; and wherein the second network entity comprises a second user equipment different from the first user equipment.

13. An apparatus of a second network entity, the apparatus comprising at least one processor, and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to: receive, from a first network entity, a configuration indicating one or more resources to be used for measuring cross-link interference between the first network entity and the second network entity; perform, based on the configuration, the measurement of the cross-link interference on the one or more resources for one or more beam pairs associated with the first network entity and the second network entity; transmit, to the first network entity, a cross-link interference measurement report indicating a result of the measurement for the one or more beam pairs associated with the first network entity and the second network entity; and coordinate with the first network entity based on the cross-link interference measurement report for mitigating the cross-link interference.

14. The apparatus according to claim 13, further being caused to: generate, based on the measurement, a table comprising a cross-link interference value measured per beam pair of the one or more beam pairs; and generate the cross-link interference measurement report based on the table.

15. The apparatus according to any of claims 13 to 14, wherein the cross-link interference measurement report comprises a list including at least one of:an identifier of at least a transmit beam of the first network entity with the strongest measured cross-link interference and one or more corresponding receive beams of the second network entity; one or more identifiers of one or more transmit beams of the first network entity with a measured cross-link interference power level above a crosslink interference power threshold and one or more corresponding receive beams of the second network entity; or one or more cross-link interference values measured per beam pair of the one or more beam pairs on the one or more resources, the one or more beam pairs comprising a transmit beam of the first network entity and a receive beam of the second network entity, respectively.

16. The apparatus according to claim 15, further being caused to: receive, from the first network entity, a configuration indicating at least one of: a number of transmit beams of the first network entity to be included in the list; or the cross-link interference power threshold.

17. The apparatus according to any of claims 15 to 16, wherein the cross-link interference measurement report further indicates a ratio of lowest received intended uplink signal power and a measured cross-link interference power level per receive beam of the second network entity.

18. The apparatus according to any of claims 15 to 17, wherein the coordination comprises at least: receiving, from the first network entity, an indication indicating at least one beam intended to be used by the first network entity in at least one time interval; determining, based on the indication and the cross-link interference measurement report, whether the at least one beam intended to be used by the firstnetwork entity is expected to interfere with at least one beam intended to be used by the second network entity in the at least one time interval; and transmitting, to the first network entity, based on the determination, an indication indicating whether the at least one beam intended to be used by the first network entity is expected to interfere with at least one beam intended to be used by the second network entity in the at least one time interval, wherein the at least one beam intended to be used by the first network entity comprises at least one transmit beam of the one or more beam pairs, and the at least one beam intended to be used by the second network entity comprises at least one receive beam of the one or more beam pairs; or wherein the at least one beam intended to be used by the first network entity comprises at least one receive beam of the one or more beam pairs, and the at least one beam intended to be used by the second network entity comprises at least one transmit beam of the one or more beam pairs.

19. The apparatus according to any of claims 15 to 18, wherein the coordination comprises at least: transmitting, to the first network entity, an indication indicating at least one beam intended to be used by the second network entity in at least one time interval; and receiving, from the first network entity, an indication indicating whether at least one beam intended to be used by the first network entity in the at least one time interval is expected to interfere with the at least one beam intended to be used by the second network entity in the at least one time interval, wherein the at least one beam intended to be used by the first network entity comprises at least one transmit beam of the one or more beam pairs, and the at least one beam intended to be used by the second network entity comprises at least one receive beam of the one or more beam pairs; or wherein the at least one beam intended to be used by the first network entity comprises at least one receive beam of the one or more beam pairs, and theat least one beam intended to be used by the second network entity comprises at least one transmit beam of the one or more beam pairs.

20. The apparatus according to any of claims 18 to 19, further being caused to: transmit or receive data in the at least one time interval using the at least one beam intended to be used by the second network entity, based on the at least one beam intended to be used by the first network entity not being expected to interfere with the at least one beam intended to be used by the second network entity.

21. The apparatus according to any of claims 18 to 19, further being caused to: re-schedule a transmission or a reception on the at least one beam intended to be used by the second network entity to another time interval where the cross-link interference is expected to be lower than in the at least one time interval according to the cross-link interference measurement report, based on the at least one beam intended to be used by the first network entity being expected to interfere with the at least one beam intended to be used by the second network entity.

22. The apparatus according to any of claims 18 to 19, further being caused to: receive, from the first network entity, information indicating one or more mitigation techniques for mitigating cross-link interference between the at least one beam intended to be used by the first network entity and the at least one beam intended to be used by the second network entity; and apply the one or more mitigation techniques.

23. The apparatus according to any of claims 18 to 19, further being caused to:transmit, to the first network entity, information indicating one or more mitigation techniques for mitigating cross-link interference between the at least one beam intended to be used by the first network entity and the at least one beam intended to be used by the second network entity, based on the at least one beam intended to be used by the first network entity being expected to interfere with the at least one beam intended to be used by the second network entity.

24. An apparatus comprising: means for transmitting, to a second network entity , a configuration indicating one or more resources to be used for measuring cross-link interference between the first network entity and the second network entity; means for receiving, from the second network entity, a cross-link interference measurement report indicating a result of the measurement for one or more beam pairs associated with the first network entity and the second network entity; and means for coordinating with the second network entity based on the cross-link interference measurement report for mitigating the cross-link interference.

25. An apparatus comprising: means for receiving, from a first network entity, a configuration indicating one or more resources to be used for measuring cross-link interference between the first network entity and the second network entity; means for performing, based on the configuration, the measurement of the cross-link interference on the one or more resources for one or more beam pairs associated with the first network entity and the second network entity; means for transmitting, to the first network entity, a cross-link interference measurement report indicating a result of the measurement for the one or more beam pairs associated with the first network entity and the second network entity; andmeans for coordinating with the first network entity based on the crosslink interference measurement report for mitigating the cross-link interference.

26. A method comprising: transmitting, to a second network entity, a configuration indicating one or more resources to be used for measuring cross-link interference between the first network entity and the second network entity; receiving, from the second network entity, a cross-link interference measurement report indicating a result of the measurement for one or more beam pairs associated with the first network entity and the second network entity; and coordinating with the second network entity based on the cross-link interference measurement report for mitigating the cross-link interference.

27. A method comprising: receiving, from a first network entity, a configuration indicating one or more resources to be used for measuring cross-link interference between the first network entity and the second network entity; performing, based on the configuration, the measurement of the crosslink interference on the one or more resources for one or more beam pairs associated with the first network entity and the second network entity; transmitting, to the first network entity, a cross-link interference measurement report indicating a result of the measurement for the one or more beam pairs associated with the first network entity and the second network entity; and coordinating with the first network entity based on the cross-link interference measurement report for mitigating the cross-link interference.

28. A non-transitory computer readable medium comprising program instructions which, when executed by an apparatus, cause the apparatus to perform at least the following:transmitting, to a second network entity, a configuration indicating one or more resources to be used for measuring cross-link interference between the first network entity and the second network entity; receiving, from the second network entity, a cross-link interference measurement report indicating a result of the measurement for one or more beam pairs associated with the first network entity and the second network entity; and coordinating with the second network entity based on the cross-link interference measurement report for mitigating the cross-link interference.

29. A non-transitory computer readable medium comprising program instructions which, when executed by an apparatus, cause the apparatus to perform at least the following: receiving, from a first network entity, a configuration indicating one or more resources to be used for measuring cross-link interference between the first network entity and the second network entity; performing, based on the configuration, the measurement of the crosslink interference on the one or more resources for one or more beam pairs associated with the first network entity and the second network entity; transmitting, to the first network entity, a cross-link interference measurement report indicating a result of the measurement for the one or more beam pairs associated with the first network entity and the second network entity; and coordinating with the first network entity based on the cross-link interference measurement report for mitigating the cross-link interference.

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