Cross link interference mitigation in wireless networks

Abstract

According to some embodiments, a method is performed by a first network node for mitigating interference in a wireless network. The method comprises receiving a reference signal configuration. The reference signal configuration comprises an indication of time and frequency resources for receiving one or more reference signals from a second network node. 5 The method further comprises measuring one or more reference signals transmitted from the second network node according to the reference signal configuration and reporting, to a third network node, a channel estimate for the second network node-to-first network node channel based on the measured one or more reference signals. 0 Figure For Publication: FIGURE 8

Description

CROSS LINK INTERFERENCE MITIGATION IN WIRELESS NETWORKSTECHNICAL FIELD

[0001] Embodiments of the present disclosure are directed to wireless communications and, more particularly, to information exchange between network nodes for cross-link interference mitigation.BACKGROUND

[0002] Generally, all terms used herein are to be interpreted according to their ordinary meaning in the relevant technical field, unless a different meaning is clearly given and / or is implied from the context in which it is used. All references to a / an / the element, apparatus, component, means, step, etc. are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. The steps of any methods disclosed herein do not have to be performed in the exact order disclosed, unless a step is explicitly described as following or preceding another step and / or where it is implicit that a step must follow or precede another step. Any feature of any of the embodiments disclosed herein may be applied to any other embodiment, wherever appropriate. Likewise, any advantage of any of the embodiments may apply to any other embodiments, and vice versa. Other objectives, features, and advantages of the enclosed embodiments will be apparent from the following description.

[0003] Third Generation Partnership Project (3GPP) New Radio (NR) standard is being designed to provide service for multiple use cases, such as enhanced mobile broadband (eMBB), ultra-reliable and low latency communication (URLLC), and machine type communication (MTC). Each of these services has different technical requirements. For example, the general requirement for eMBB is high data rate with moderate latency and moderate coverage, while URLLC service requires a low latency and high reliability transmission but perhaps for moderate data rates.

[0004] An NR slot consists of several orthogonal frequency division multiplexing (OFDM) symbols, according to current agreements either 7 or 14 symbols (OFDM subcarrier spacing < 60 kHz) and 14 symbols (OFDM subcarrier spacing > 60 kHz).

[0005] FIGURE 1 illustrates a slot with 14 OFDM symbols. In FIGURE 1 , Tsand Tsymbdenote the slot and OFDM symbol duration, respectively.

[0006] NR supports different types of duplex communication modes. To support the many types of targeted use cases with varying requirements, different duplex communication modes are discussed in 3GPP standardization. Moreover, the same device may be capable of operating using different duplex modes, e.g., to achieve different overall communication performance based on its needs.

[0007] Transmission and reception from a wireless communication device, e.g., a base station (BS) or a user equipment (UE) in a cellular system, can be multiplexed in the frequency domain or in the time domain (or combinations thereof). The most relevant duplex modes are discussed below.

[0008] Duplex communication modes include frequency division duplex (FDD) and time division duplex (TDD).

[0009] FDD, as illustrated in the top left in FIGURE 2 (a), implies that transmission (TX) and reception (RX) take place in different, sufficiently separated carriers. Thus, FDD requires paired spectrum. For FDD operation, there are two carrier frequencies, one for uplink (UL) transmission and one for downlink (DL) transmission. At least with respect to the UE in a cellular communication system, FDD can be either full duplex (FD-FDD) or half duplex (HD- FDD).

[0010] In the FD-FDD case, a UE can transmit and receive simultaneously, while in HD-FDD operation, the UE cannot transmit and receive simultaneously (the BS is still capable of simultaneous RX / TX though, e.g., receiving from one UE while simultaneously transmitting to another UE). In Long Term Evolution (LTE), a HD-FDD terminal is monitoring / receiving in the DL except when explicitly being instructed to transmit in a certain subframe.

[0011] FIGURE 2 illustrates different types of duplex communication modes, (a) FDD, (b) TDD, (c) subband frequency division (SBFD), and (d) inband frequency division (IBFD).

[0012] FIGURE 3 illustrates a comparison of TDD operations, (a) static TDD in channel 1 and 2, and (b) static TDD in channel 2 and dynamic TDD in channel 1.

[0013] FIGURE 4 illustrates TDD operation options and interference cases.

[0014] For TDD, as illustrated to the top right in FIGURE 2 (b), TX and RX take place within the same carrier in different, non-overlapping time slots. Thus, TDD can operate in unpaired spectrum. For TDD operation, there is only a single carrier frequency and UL and DL transmissions are always separated in time also on a cell basis. Because the same carrierfrequency is used for UL and DL transmission, both the BS and the UEs need to switch from TX to RX and vice versa.

[0015] An essential aspect of any TDD system is to provide the possibility for a sufficiently large guard time where neither DL nor UL transmissions occur. This is required to avoid interference between UL and DL transmissions. For NR, this guard time is provided by special sots, which are split into three parts: symbols for DL, a guard period (GP), and symbols for UL. The remaining slots are either allocated to UL or DL transmission.

[0016] The only interference existing in this configuration is among transmissions happening on the same link, inside their own channel, and from an adjacent channel, if synchronization is also assumed among different operators. This is shown in FIGURE 3 (a), where the two networks deployed in channels 1 and 2 are synchronized and will suffer only from in-channel and adjacent channel interference from the same link.

[0017] Interference links are further described in FIGURE 4 (a). This option is, e.g., used by operators in Europe and recommended in regulations, and requires entire carrier bandwidth or all carriers in the same frequency band to use the same DL transmission or UL reception directions.

[0018] Dynamic TDD describes a mode of operation in which a network adapts the DL / UL subframe pattern according to traffic conditions. This causes interference between different links (uplink and downlink), and it is referred to as cross link interference (CLI), BS-to-BS and UE-to-UE, as it is shown in FIGURE 4 (b).

[0019] CLI interference happens inside the same operator and inter-operators. FIGURE 3 (b) provides an example. Specifically, the deployment on channel 1 requires additional UL slots to serve UL traffic, and to do that the TDD patterns of BS1 and BS2 are adjusted to increase UL ratio. Due to that, the deployment will suffer, inside the same network, from BS-to-BS and UE-to-UE interference in slots 2 and 3.

[0020] In addition, the patterns used in channel 1 are unsynchronized with respect to the static TDD pattern used in channel 2. Due to that, the deployment in channel 1 will suffer from BS- to-BS and UE-to-UE interference from the adjacent channel, in slots 2, 3 and 4. On channel 2 instead, the deployment will suffer from UE-to-UE interference from the adjacent channel in slots 2, 3 and 4, but only from same link interference inside channel 2.

[0021] Subband full duplex (SBFD), as illustrated to the bottom left in FIGURE 2 (c), is being studied in 3GPP Release 18 as a part of the 5G- Advanced standardization. For SBFD operation,a portion of a wide bandwidth carrier, termed subband, may be used for a different communication direction than that of the rest of the carrier. Correspondingly, different nonoverlapping subbands are used for DL and UL. This is unlike the conventional TDD operation where the entire bandwidth of the carrier is always used either for DL or UL. SBFD operation can also be performed across different carriers within the same frequency band, where one or more carriers within a frequency band may be used for a different communication direction than that of the other carriers, which is again unlike conventional TDD operation where all carriers within a frequency band are always used for the same communication direction.

[0022] In the 3GPP Release 18 study, the scope has been limited such that during SBFD communication, only base stations transmit downlink and receive uplink simultaneously using corresponding non-overlapping subbands. An individual UE is scheduled in only one direction (DL or UL) at a time, following conventional HD TDD operation. However, for future 3 GPP releases, SBFD operation at UEs where a UE transmits UL and receives DL simultaneously using corresponding non-overlapping subbands is also being discussed as a potential study topic. Interference links affecting a SBFD Rel. 18 deployments are shown in FIGURE 4 (c).

[0023] Single frequency full duplex (SFFD) or in-band full duplex (IBFD), as illustrated at the bottom right in FIGURE 2 (d), has also been proposed to be studied in 3GPP standardization. It was discussed but excluded from the scope of Release 18, and it is now again being discussed during scoping discussions for future releases. For SFFD operation, the entire bandwidth of the same carrier in a single carrier system or all carriers in a multi-carrier system can be simultaneously used for DL and UL operations. In other words, the same time and frequency resources can be used for both TX and RX at the same device. Similar to SBFD operation, SFFD operation is also being discussed for both base stations and UEs.

[0024] As shown in the Figure 4, BS-BS CLI or gNB-gNB CLI plays a significant role in the functionality of SBFD or dynamic TDD. Many BS-BS CLI mitigation schemes were studied in TR 38.858 and each method required some exchange of information between gNBs. However, the details of the information were not studied. It is worth noting that the exchange of information is likely among gNBs of same operator.

[0025] The following is a table of the schemes for gNB-gNB CLI mitigation handling in the TR 38.858. The schemes proposed for SBFD were also applicable to dynamic TDD and flexible TDD network deployments. Additionally, there are specific mechanisms that havebeen exclusively discussed for enhancing CLI mitigation in dynamic / flexible TDD deployments.Table 1: gNB-gNB CLI mitigation schemes for SBFD and dynamic / flexible TDD in TR38.858

[0026] There currently exist certain challenges. For example, from the schemes for gNB-gNB CLI mitigation, there are two pivotal points to consider for the mitigation schemes to work.One is configuring measurement resources / reference signals for gNB-gNB channel measurement, and two is the exchange of information between gNBs.

[0027] In addition to identifying reference signals for gNB-gNB channel measurement, it prompts several operational questions:• Resource Allocation: Determining which gNBs are responsible for transmitting the reference signals is essential. This decision cannot be arbitrary, as it directly impacts the effectiveness of the channel measurement and, consequently, the performance of the overall network.• Synchronization: There needs to be a clear mechanism for gNBs to be aware of the timing and frequency allocations of the reference signals. Without a synchronized understanding, the risk of interference increases, potentially compromising the accuracy of channel measurements.• Dynamic order: The role of a gNB as an aggressor or a victim in the context of interference is not static and can change depending on the network topology and traffic conditions. This fluidity necessitates a dynamic approach to assigning the transmission of reference signals, ensuring that all potential interference scenarios are mitigated. As part of this, it is essential that gNB-gNB communication can follow such dynamicity without incurring delayed information exchanges, which could lead to victim gNBs behaving as aggressors and vice versa.• Resource information sharing: The method by which the resource configurations are communicated and shared among gNBs needs to be defined. The proposed methods in the TR assume that this type of information could be shared using Xn protocol in a radio access node.SUMMARY

[0028] As described above, certain challenges currently exist with cross link interference (CLI) mitigation in wireless networks. Certain aspects of the present disclosure and their embodiments may provide solutions to these or other challenges. For example, particular embodiments provide methods to determine which gNBs transmit the reference signals and which gNBs listen for the reference signals.

[0029] Particular embodiments provide methods for the gNBs to know when to transmit reference signals for CLI channel measurement.

[0030] Particular embodiments provide methods for gNBs to determine which reference signals to transmit for gNB-gNB channel measurement.

[0031] Particular embodiments provide methods for the gNBs to synchronize the timing of reference signals among gNBs.

[0032] Particular embodiments provide methods to determine which gNBs should take part in cross node CLI mitigation procedures, and which gNBs are to be excluded.

[0033] Particular embodiments provide methods for the gNBs to share the information among gNBs.

[0034] Particular embodiments provide methods for the exchange of information between nodes / functions of a radio access network that enable such nodes / functions to coordinate CLI optimization operations aimed at reducing cross node interference.

[0035] The embodiments described herein include determining the role of each participating node as, for example, aggressor or victim, as well as exchanging information about the availability and the time frequency coordinates for the occurrence of reference signals transmissions that may be used for channel estimation and therefore to take actions aimed at reducing cross link interference. Particular embodiments involve the exchange of information concerning muting of resources that may serve the purpose of better isolating the transmitted reference signals and therefore better estimate inter node channels. Moreover, particular embodiments include the exchange of timing information that enables participating nodes to determine at what point in time reference signals and resource muting occur, or that helps determine the quality of the node internal uplink / downlink transmission alignment, which determines how effective CLI reduction techniques may be.

[0036] According to some embodiments, a method is performed by a first network node for mitigating interference in a wireless network. The method comprises receiving a reference signal configuration. The reference signal configuration comprises an indication of time and frequency resources for receiving one or more reference signals from a second network node. The method further comprises measuring one or more reference signals transmitted from the second network node according to the reference signal configuration and reporting, to a third network node, a channel estimate for the second network node-to-first network node channel based on the measured one or more reference signals.

[0037] In particular embodiments, the method further comprises transmitting a request for interference mitigation to the third network node. The request is based on the measured one or more reference signals.

[0038] In particular embodiments, the method further comprises receiving a request for interference mitigation from the third network node. The request is based on the reported channel estimate.

[0039] In particular embodiments, the one or more reference signals comprise one or more SSBs.

[0040] In particular embodiments, the reference signal configuration further comprises an indication of a SBFD configuration for the second network node. The reference signal configuration may comprise an indication of an uplink / downlink timing offset for the second network node.

[0041] In particular embodiments, the first network node comprises a victim network node and one of the second network node and the third network node comprise an aggressor network node. In particular embodiments, the first network node comprises an aggressor network node and one of the second network node comprises a victim network node.

[0042] In particular embodiments, the reference signal configuration is received from the second network node or the third network node. The third network node may be the same network node as the second network node. The third network node may comprise an 0AM network node.

[0043] According to some embodiments, a method is performed by a second network node for mitigating interference in a wireless network. The method comprises transmitting a reference signal configuration to a first network node. The reference signal configuration comprises an indication of time and frequency resources the second network node will use for transmitting one or more reference signals. The method further comprises transmitting one or more reference signals according to the reference signal configuration and receiving, from the first network node, a channel estimate for the second network node-to-first network node channel based on the transmitted one or more reference signals.

[0044] In particular embodiments, the method further comprises transmitting a request for interference mitigation to the first network node, the request based on the received channel estimate.

[0045] In particular embodiments, the method further comprises receiving a request for interference mitigation from the first network node, the request based on the transmitted one or more reference signals.

[0046] According to some embodiments, a network node comprises processing circuitry operable to perform any of the network node methods described above.

[0047] Another computer program product comprises a non-transitory computer readable medium storing computer readable program code, the computer readable program code operable, when executed by processing circuitry to perform any of the methods performed by the network nodes described above.

[0048] Certain embodiments may provide one or more of the following technical advantages. For example, particular embodiments aid in gNB-gNB or downlink-to-uplink interference reduction in subband full duplex (SBFD) networks. Although there are other aspects, such as self-interference, inter-sector interference, and adjacent channel interference, the information exchange aids in reducing interference and potentially blocking in gNBs across different sites.BRIEF DESCRIPTION OF THE DRAWINGS

[0049] For a more complete understanding of the disclosed embodiments and their features and advantages, reference is now made to the following description, taken in conjunction with the accompanying drawings, in which:FIGURE 1 illustrates a slot with 14 OFDM symbols;FIGURE 2 illustrates different types of duplex communication modes, (a) frequency division duplex (FDD), (b) time division duplex (TDD), (c) subband full duplex (SBFD), and (d) inband full duplex (IBFD));FIGURE 3 illustrates a comparison of TDD operations, (a) static TDD in channel 1 and 2, and (b) static TDD in channel 2 and dynamic TDD in channel 1 ;FIGURE 4 illustrates TDD operation options and interference cases;FIGURE 5 illustrates an example communication system, according to certain embodiments;FIGURE 6 illustrates an example user equipment (UE), according to certain embodiments;FIGURE 7 illustrates an example network node, according to certain embodiments;FIGURE 8 illustrates a method performed by a first network node, according to certain embodiments; andFIGURE 9 illustrates a method performed by a second network node, according to certain embodiments.DETAILED DESCRIPTION

[0050] As described above, certain challenges currently exist with cross link interference (CLI) mitigation in wireless networks. Certain aspects of the present disclosure and their embodiments may provide solutions to these or other challenges. For example, particular embodiments provide methods to determine which gNBs transmit the reference signals and which gNBs listen for the reference signals.

[0051] Particular embodiments are described more fully with reference to the accompanying drawings. Other embodiments, however, are contained within the scope of the subject matter disclosed herein, the disclosed subject matter should not be construed as limited to only the embodiments set forth herein; rather, these embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art.

[0052] The scenario of non-split radio access network (RAN) architecture and of a network made of gNBs is used as an example for particular embodiments described herein. Such an example should be considered non-limiting. Namely, the embodiments described herein may equivalently apply if the node identified as a gNB is substituted by a gNB-distributed unit (DU), an eNB, an eNB-DU, or where the RAN is formed by a mixture of all such nodes. Therefore, where the disclosure mentions “gNB,” it should be understood that the node could be a gNB-DU, an eNB, an eNB-DU, or any other RAN node capable of transmitting and receiving over radio access resources and generating cross node interference.

[0053] The embodiment descriptions assume that subband full duplex (SBFD) configuration is enabled in gNBs.

[0054] A first group embodiments are directed to determining which gNBs transmit reference signals. A number of embodiments to determine how to select which gNBs transmit signals for gNB-gNB channel measurement are disclosed.

[0055] In some embodiments (la), all gNBs transmit reference signals. In these embodiments, one of multiple gNBs transmit a reference signal in a given slot in predeterminedtime and frequency resources while one or multiple gNBs listen to the transmission(s) at a given time.

[0056] In some embodiments, one gNB in the network transmits the reference signals in a slot in a predetermined set of time and frequency resources and the remaining gNBs in the network listen to the signal. In some embodiments, multiple gNBs in the network transmit the reference signals in a slot in a predetermined set of time and frequency resources and one gNB in the network listens to the signal.

[0057] In particular embodiments, the gNBs involved in transmitting and receiving the reference signals exchange information over interfaces that interconnect such nodes, such as the Xn, to inform each other about the time and frequency resources over which the reference signals are transmitted. In particular embodiments, the information signaled between nodes is complemented by the type of reference signal that each RAN node will signal over the air. As an example, such a signal may be a demodulation reference signal (DMRS).

[0058] In particular embodiments, RAN nodes involved in signaling and receiving the reference signals are configured by the operation, administration, and maintenance (0AM) system with respect to which time and frequency resources to use for signaling specific reference signals and to receive specific reference signals from neighbor RAN nodes.

[0059] In some embodiments (lb), a victim gNB determines which gNBs should receive the reference signals. In these embodiments, a victim gNB that determines its uplink performance is affected by gNB-gNB interference identifies a list of gNBs to which to transmit the reference signals. In some embodiments, the list of gNBs is the neighbor-cell list in the information element (IE) Neighbor information NR. In some embodiments, the victim gNB sends a request to a local or central control node in the network, and the local or central control node determines the list of aggressor gNBs to which to transmit the reference signals. In some embodiments, the gNB is configured by the 0AM system with information concerning which RAN nodes are the aggressors to a given victim RAN node that will receive the reference signal, which reference signal to transmit, and / or the frequency and time resources on which to transmit the reference signal.

[0060] In particular embodiments, the victim gNB receives reference signals from other gNBs and determines the set of aggressor gNBs based on the received signal strengths from the respective gNBs. In one non-limiting example, the reference signals are synchronization signal blocks (SSBs). The SSB is designed for blind detection, that is it may be detected withlimited information regarding timing and sequences. In a second optional step, the victim gNB requests its connected user equipment (UEs) to read the global cell identity of the identified aggressor gNBs and report the identity back to the victim gNB.

[0061] By means of this procedure, the victim gNB may decide to establish, if not already in place, an interface with the aggressor node for inter-node communication and CLI coordination. Alternatively, the victim gNB, if already connected via an interface with the aggressor gNB, may signal to the aggressor information concerning inter-node CLI coordination, such as time and frequency resources on which to monitor certain reference signals to determine how to reduce CLI. This procedure may preferably be executed when the gNB starts and / or periodically.

[0062] In particular embodiments, the victim gNB uses UE measurements to determine the set of aggressor gNBs. That is, the set of aggressor gNBs are determined based on UE measurements that are reported to the gNB. For example, all neighbor cells with a reference signal received power (RSRP) that is within a range of the RSRP of the serving cell is considered part of the aggressor gNB set.

[0063] In some embodiments (1 c), a victim gNB in SBFD operation transmits the reference signals. In these embodiments, a victim gNB in SBFD operation transmits reference signals in a given slot with predetermined time and frequency resources to enable gNB-gNB interference measurement by its neighboring cells.

[0064] In some embodiments, a gNB in SBFD operation transmits reference signals periodically with a predefined or configured periodicity. In some embodiments, a gNB in SBFD operation transmits reference signals periodically in synchronization to SSB or a periodic / semi-persistent channel state information reference signal (CSI-RS) transmission.

[0065] In particular embodiments, the victim gNB is configured by the 0AM system with respect to the time and frequency resources and periodicity used to signal the reference signals.

[0066] In some embodiments (Id), an aggressor gNB in SBFD operation transmits the reference signals. In these embodiments, an aggressor gNB in SBFD operation transmits reference signals in a given slot with predetermined time and frequency resources to enable gNB-gNB interference measurement by its neighboring cells.

[0067] In some embodiments, a gNB in SBFD operation transmits reference signals periodically with a predefined or configured periodicity. In some embodiments, a gNB in SBFD operation transmits reference signals periodically in synchronization to SSB or aperiodic / semi-persistent CSI-RS transmission. In particular embodiments, the victim gNB is configured by the 0AM system with respect to the time and frequency resources and periodicity used to signal the reference signals.

[0068] A second group of embodiments are directed to reference signal configuration. In these embodiments, the time and frequency location of the reference signal configuration and the reference signal itself are disclosed.

[0069] Some embodiments (2a) include periodic CSI-RS. In particular embodiments, the existing periodic CSI-RS framework is used for estimating gNB-gNB channel. RAN nodes participating in CLI optimization signal CSI-RS transmission configuration between each other to enable the correct reception of CSI-RS signals from neighbor nodes and determine how to optimize CLI.

[0070] Some embodiments (2b) include physical downlink control channel (PDCCH) or physical downlink shared channel (PDSCH) embodiments. In particular embodiments, a preconfigured reference PDCCH or PDSCH is used for estimating the gNB-gNB channel. RAN nodes participating in CLI optimization signal PDCCH or PDSCH transmission configuration between each other to enable the correct reception of PDCCH or PDSCH signals from neighbor nodes and determine how to optimize CLI.

[0071] Some embodiments (2c) include a new periodic signal based on existing reference signals. In particular embodiments, a new signal based on existing reference signals may be periodically configured. RAN nodes participating in CLI optimization signal the new reference signal configuration between each other to enable the correct reception of the new reference signals from neighbor nodes and determine how to optimize CLI.

[0072] Some embodiments (2d) include SSB embodiments. In these embodiments, an SSB is used to estimate the gNB-gNB channel. In one variant the strongest SSB, that is the one with the highest RSRP (or an SSB that has stronger signal power compared to the other SSBs), is used to estimate the channel. In another variant, the channel is estimated for a set of SSBs, and the nulling precoder is based on a combination of the channel measurements. In one nonlimiting example, each of the individual channel estimates is used. In another example, the average of them is used. RAN nodes participating in CLI optimization signal SSB transmission configuration between each other to enable the correct reception of SSB signals from neighbor nodes and determine how to optimize CLI.

[0073] Some embodiments (2e) include DMRS embodiments. In particular embodiments, a preconfigured reference DMRS is used for estimating the gNB-gNB channel. RAN nodes participating in CLI optimization signal DMRS transmission configuration between each other to enable the correct reception of DMRS signals from neighbor nodes and determine how to optimize CLI.

[0074] Some embodiments (21) include resource muting. In particular embodiments, RAN nodes participating in the procedure of CLI optimization may signal between each other time and frequency resources for which muting may be applied. Such muted resources may correspond to the time and frequency location of reference signals signaled by other nodes in the cluster of nodes involved in CLI optimization. Optionally, more information may be included together with the configuration of time and frequency resources for which muting is applied, such as information about signals emitted on such time and frequency resources in case muting is not applied in full (partial muting), and / or transmission power of the left over transmissions on the partially muted resources.

[0075] Some embodiments (2g) include coordination of RS signaling and resource muting. In particular embodiments, depending on whether RAN nodes participating in CLI optimization are aggressors or victims, there may be coordination on which RAN node signals reference signals, which RAN node detects such reference signals, and which RAN node applies resource muting. For this purpose, RAN nodes may exchange signaling between each other where it is specified which RAN node and which cell served by such RAN node will signal specific reference signals, including the time and frequency resources for such transmissions. Optionally, such signaling may include also other information about the reference signals transmitted such as transmission power. RAN nodes may exchange signaling where it is specified which RAN node and which cell served by such RAN node will apply resource muting, including the time and frequency resources for which muting is applied.

[0076] Optionally, the signaling may indicate also which RAN node should detect and receive the reference signals emitted by a given RAN node and cell. This is the case where, for example, a RAN node signals to a neighbor RAN node that a given reference signal is transmitted on a given set of time and frequency resources and where the receiving RAN node constitutes a split RAN gNB, formed by many gNB-DUs. For the receiving gNB-central unit (CU) to determine to which of its connected gNB-DUs the signaling message should be forwarded, there is a need that the source RAN node includes details of, for example, the cellsof the node that should listen to such reference signals. This allows the target gNB-CU to forward the message to the appropriate target gNB-DUs, which will in turn listen to the reference signal transmitted by the source RAN node and, for example, estimate the channel between them and the source RAN node.

[0077] A third group of embodiments are directed to the order of transmitting reference signals.

[0078] Some embodiments (3a) include a round robin ordering. In particular embodiments, the gNBs in the network transmit the reference signals in a round robin fashion over a set of one or more cells. In these embodiments, the periodicity or timing per cell of the signals transmitted by each RAN node is signaled by each RAN node to other connected nodes taking part in CLI optimization over inter-node interfaces such as the Xn. In particular embodiments, the periodicity or timing per cell of such reference signals is configured at each participating RAN node by the 0AM system, namely the configuration consists of specifying the reference signal periodicity or timing for each cell and node neighboring a given node.

[0079] Some embodiments (3b) include a cell ID that matches a slot number. In particular embodiments, a gNB in the network determines a slot to transmit the reference signal based on the cell identity of the cell over which the reference signal will be transmitted. In some embodiments, a gNB that has a cell ID (nr-PhysCelllD or nr-CellGloballD) that matches the slot number is enabled to transmit the reference signal. In a non-limiting example, the matching between cell ID and slot number may be: slot number = mod (cell ID, number of slots in a radio frame).

[0080] In particular embodiments, the gNB in the network determines a system frame number (SFN) in which to transmit the reference signal based on its cell identity. In these embodiments, the periodicity or timing per cell of the signals transmitted by each RAN node is signaled by each RAN node to other connected nodes taking part in CLI optimization over inter-node interfaces such as the Xn. In particular embodiments, the periodicity or timing per cell of such reference signals is configured at each participating RAN node by the 0AM system, namely the configuration consists of specifying the reference signal periodicity or timing for each cell and node neighboring a given node.

[0081] Some embodiments (3c) include a determination by a local / central control node. In particular embodiments, the order of gNB transmitting reference signals is determined by a local / central control node in the network, such as the 0AM system.

[0082] A fourth group of embodiments includes exchange of information.

[0083] Some embodiments (4a) include reference signal configuration exchange over Xn interface. In particular embodiments, the reference signal, its periodicity and time and frequency resources area exchanged over Xn interface between gNBs.

[0084] Some embodiments (4b) include SBFD TDD configuration. In particular embodiments, the SBFD slot format is exchanged over Xn interface.

[0085] Some embodiments (4c) include a request for TX nulling, where the victim transmits RS. In particular embodiments, a victim gNB requests an aggressor gNB to perform TX nulling towards it. The victim gNB includes information regarding a reference signal it will transmit for the aggressor gNB to be able to determine the nulling precoder. This information may, for example, be the time and frequency resources and parameters for determining the reference signal sequence. Optionally, the request also includes a time duration during which the nulling should be performed. The time when the reference signal is transmitted may for example be determined based on the third group of embodiments described above.

[0086] In particular embodiments, the aggressor gNB confirms that it will perform nulling.

[0087] The victim gNB may determine which of the aggressor gNBs to request nulling from based on, e.g., the first group of embodiments (such as lb).

[0088] Some embodiments (4d) include a request for TX nulling, where the aggressor transmits RS. In particular embodiments, a victim gNB requests an aggressor gNB to perform TX nulling towards it. Optionally, the request also includes a time duration during which the nulling should be performed. In the response the aggressor gNB includes information regarding a reference signal, the information may be transmitted to the victim gNB to be able to estimate the channel. This information may, for example, be the time and frequency resources and parameters for determining the reference signal sequence. The victim gNB then estimates the channel and sends the channel estimate back to the aggressor gNB so it may determine the nulling precoder.

[0089] The time when the reference signal is transmitted may for example be determined based on the third group of embodiments described above.

[0090] In particular embodiments, the aggressor gNB confirms that it will perform nulling.

[0091] The victim gNB may determine which of the aggressor gNBs to request nulling from based on, e.g., the first group of embodiments (such as lb).

[0092] Some embodiments (4e) include a request for channel estimate, where the aggressor transmits RS. In particular embodiments, an aggressor gNB requests a victim gNB to performa gNB-gNB channel measurement towards it. In the request, the aggressor gNB includes information regarding a reference signal it will transmit for the victim gNB to be able to estimate the channel. This information may, for example, be the time and frequency resources and parameters for determining the reference signal sequence. The victim gNB then estimates the channel and responds with the channel estimate to the aggressor gNB. The aggressor gNB then uses the channel estimate to null towards the victim gNB. In one optional step, the victim gNB confirms that it wants to be nulled to and optionally provides a time interval during which the nulling should be performed.

[0093] The aggressor gNB may determine which of the victim gNBs to channel estimates from based on, e.g., the first group of embodiments (such as lb).

[0094] Some embodiments (41) include a channel report instead of a channel estimate, where the aggressor transmits RS. In particular embodiments, instead of the victim sending the full channel estimate (as in embodiments 4d and 4e), a channel report is sent. The victim gNB estimates the channel and sends a channel report back to the aggressor gNB. The aggressor gNB then uses the channel report to compute a nulling precoder toward the victim gNB.

[0095] In particular embodiments, the channel report is done in the same way as a UE CSI report, including type I and type II CSI reporting.

[0096] In particular embodiments, the victim gNB applies a number of pre-determined precoders to the channel estimate and the channel report consists of the precoder that results in the largest (or larger) received power compared to other precoders. The channel report may consist of an indication of the identified precoder and the resulting received power. In particular embodiments, the set of pre-determined precoders is fixed in the specifications. For example, the same set as used for UE CSI reporting. In another example, the aggressor gNB sends the set of precoders in the first request.

[0097] In particular embodiments, the victim gNB performs channel compression and transmits the compressed channel. The channel compression may, for example, be done using an autoencoder.

[0098] In particular embodiments, the victim gNB performs a singular value or eigen value decomposition of the channel covariance and sends the decomposition instead. In particular embodiments, the victim only sends the N largest singular values / eigen values together with their associated eigen vectors.

[0099] Some embodiments (4e) include exchange of timing information. In particular embodiments, the RAN nodes participating in CLI optimization exchange different types of timing information. In one non-limiting embodiment, the RAN nodes exchange the timing of their radio frame and sub frame transmission. One example of such timing may be to signal to another RAN node, for each served cell, a time offset calculated with respect to an absolute time reference for the start of the transmission of a radio frame or of a specific subframe.

[0100] In another non-limiting example, the timing information signaled identifies the starting point in time of the transmission of a sequence of reference signals. Such timing information may be represented as the time offset calculated with respect to an absolute time reference, namely the time offset from such an absolute point in time to the start of the transmission of the first reference signal of a sequence of reference signals. The sequence of reference signals may be expressed by a representation of the time between consecutive reference signals and a representation of the frequency resources for each transmitted reference signal. With this information, a receiving node is able to determine when the reference signals transmitted over neighboring cells will occur.

[0101] In another non-limiting example, the timing information described above applies to a pattern of muted resources. Namely, a node may signal, for each cell for which muting is applied, a time offset calculated with respect to an absolute time reference, namely the time offset from such absolute point in time to the start of the first resource that is muted. The sequence of muted resources may be expressed by a representation of the time between consecutive muted resources and a representation of the frequency resources for each muted resource. With this information, a receiving node is able to determine when muted resources occur in neighboring cells.

[0102] In particular embodiments, a RAN node signals to other RAN nodes involved in CLI optimization, for each cell included in the CLI optimization process, information about the cell uplink / downlink timing offset, namely the amount of time for which uplink transmissions and downlink transmissions are offset. This information is important because a large uplink / downlink timing offset undermines the effectiveness of CLI mitigation techniques. It might therefore be appropriate that cells with a large uplink / downlink timing offset are not included in the process of CLI optimization.

[0103] In one example, once the uplink / downlink timing offset is received from all the nodes and for all the cells taking part in the CLI optimization process, nodes may determine which ofsuch cells and nodes will be removed from the group of cells / nodes to take part in CLI optimization. One criteria for such removal may be that the uplink / downlink timing offset is higher than a given threshold. In another example, the exchange of uplink / downlink timing offset information may help determine which CLI mitigation technique is the most opportune.

[0104] FIGURE 5 illustrates an example of a communication system 100 in accordance with some embodiments. In the example, the communication system 100 includes a telecommunication network 102 that includes an access network 104, such as a radio access network (RAN), and a core network 106, which includes one or more core network nodes 108. The access network 104 includes one or more access network nodes, such as network nodes 110a and 110b (one or more of which may be generally referred to as network nodes 110), or any other similar 3rd Generation Partnership Project (3GPP) access node or non-3GPP access point. The network nodes 110 facilitate direct or indirect connection of user equipment (UE), such as by connecting UEs 112a, 112b, 112c, and 112d (one or more of which may be generally referred to as UEs 112) to the core network 106 over one or more wireless connections.

[0105] Example wireless communications over a wireless connection include transmitting and / or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and / or other types of signals suitable for conveying information without the use of wires, cables, or other material conductors. Moreover, in different embodiments, the communication system 100 may include any number of wired or wireless networks, network nodes, UEs, and / or any other components or systems that may facilitate or participate in the communication of data and / or signals whether via wired or wireless connections. The communication system 100 may include and / or interface with any type of communication, telecommunication, data, cellular, radio network, and / or other similar type of system.

[0106] The UEs 112 may be any of a wide variety of communication devices, including wireless devices arranged, configured, and / or operable to communicate wirelessly with the network nodes 110 and other communication devices. Similarly, the network nodes 110 are arranged, capable, configured, and / or operable to communicate directly or indirectly with the UEs 112 and / or with other network nodes or equipment in the telecommunication network 102 to enable and / or provide network access, such as wireless network access, and / or to perform other functions, such as administration in the telecommunication network 102.

[0107] In the depicted example, the core network 106 connects the network nodes 110 to one or more hosts, such as host 116. These connections may be direct or indirect via one or moreintermediary networks or devices. In other examples, network nodes may be directly coupled to hosts. The core network 106 includes one more core network nodes (e.g., core network node 108) that are structured with hardware and software components. Features of these components may be substantially similar to those described with respect to the UEs, network nodes, and / or hosts, such that the descriptions thereof are generally applicable to the corresponding components of the core network node 108. Example core network nodes include functions of one or more of a Mobile Switching Center (MSC), Mobility Management Entity (MME), Home Subscriber Server (HSS), Access and Mobility Management Function (AMF), Session Management Function (SMF), Authentication Server Function (AUSF), Subscription Identifier De-concealing function (SIDF), Unified Data Management (UDM), Security Edge Protection Proxy (SEPP), Network Exposure Function (NEF), and / or a User Plane Function (UPF).

[0108] The host 116 may be under the ownership or control of a service provider other than an operator or provider of the access network 104 and / or the telecommunication network 102 and may be operated by the service provider or on behalf of the service provider. The host 116 may host a variety of applications to provide one or more service. Examples of such applications include live and pre-recorded audio / video content, data collection services such as retrieving and compiling data on various ambient conditions detected by a plurality of UEs, analytics functionality, social media, functions for controlling or otherwise interacting with remote devices, functions for an alarm and surveillance center, or any other such function performed by a server.

[0109] As a whole, the communication system 100 of FIGURE 5 enables connectivity between the UEs, network nodes, and hosts. In that sense, the communication system may be configured to operate according to predefined rules or procedures, such as specific standards that include, but are not limited to: Global System for Mobile Communications (GSM); Universal Mobile Telecommunications System (UMTS); Long Term Evolution (LTE), and / or other suitable 2G, 3G, 4G, 5G standards, or any applicable future generation standard (e.g., 6G); wireless local area network (WLAN) standards, such as the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards (WiFi); and / or any other appropriate wireless communication standard, such as the Worldwide Interoperability for Microwave Access (WiMax), Bluetooth, Z-Wave, Near Field Communication (NFC) ZigBee, LiFi, and / or any low-power wide-area network (LPWAN) standards such as LoRa and Sigfox.

[0110] In some examples, the telecommunication network 102 is a cellular network that implements 3GPP standardized features. Accordingly, the telecommunications network 102 may support network slicing to provide different logical networks to different devices that are connected to the telecommunication network 102. For example, the telecommunications network 102 may provide Ultra Reliable Low Latency Communication (URLLC) services to some UEs, while providing Enhanced Mobile Broadband (eMBB) services to other UEs, and / or Massive Machine Type Communication (mMTC) / Massive loT services to yet further UEs.[oni] In some examples, the UEs 112 are configured to transmit and / or receive information without direct human interaction. For instance, a UE may be designed to transmit information to the access network 104 on a predetermined schedule, when triggered by an internal or external event, or in response to requests from the access network 104. Additionally, a UE may be configured for operating in single- or multi -RAT or multi-standard mode. For example, a UE may operate with any one or combination of Wi-Fi, NR (New Radio) and LTE, i.e. being configured for multi-radio dual connectivity (MR-DC), such as E-UTRAN (Evolved-UMTS Terrestrial Radio Access Network) New Radio - Dual Connectivity (EN-DC).

[0112] In the example, the hub 114 communicates with the access network 104 to facilitate indirect communication between one or more UEs (e.g., UE 112c and / or 112d) and network nodes (e.g., network node 110b). In some examples, the hub 114 may be a controller, router, content source and analytics, or any of the other communication devices described herein regarding UEs. For example, the hub 114 may be a broadband router enabling access to the core network 106 for the UEs. As another example, the hub 114 may be a controller that sends commands or instructions to one or more actuators in the UEs. Commands or instructions may be received from the UEs, network nodes 110, or by executable code, script, process, or other instructions in the hub 114. As another example, the hub 114 may be a data collector that acts as temporary storage for UE data and, in some embodiments, may perform analysis or other processing of the data. As another example, the hub 114 may be a content source. For example, for a UE that is a VR headset, display, loudspeaker or other media delivery device, the hub 114 may retrieve VR assets, video, audio, or other media or data related to sensory information via a network node, which the hub 114 then provides to the UE either directly, after performing local processing, and / or after adding additional local content. In still another example, the hub 114 acts as a proxy server or orchestrator for the UEs, in particular in if one or more of the UEs are low energy loT devices.

[0113] The hub 114 may have a constant / persistent or intermittent connection to the network node 110b. The hub 114 may also allow for a different communication scheme and / or schedule between the hub 114 and UEs (e.g., UE 112c and / or 112d), and between the hub 114 and the core network 106. In other examples, the hub 114 is connected to the core network 106 and / or one or more UEs via a wired connection. Moreover, the hub 114 may be configured to connect to an M2M service provider over the access network 104 and / or to another UE over a direct connection. In some scenarios, UEs may establish a wireless connection with the network nodes 110 while still connected via the hub 114 via a wired or wireless connection. In some embodiments, the hub 114 may be a dedicated hub - that is, a hub whose primary function is to route communications to / from the UEs from / to the network node 110b. In other embodiments, the hub 114 may be a non-dedicated hub - that is, a device which is capable of operating to route communications between the UEs and network node 110b, but which is additionally capable of operating as a communication start and / or end point for certain data channels.

[0114] FIGURE 6 shows a UE 200 in accordance with some embodiments. As used herein, a UE refers to a device capable, configured, arranged and / or operable to communicate wirelessly with network nodes and / or other UEs. Examples of a UE include, but are not limited to, a smart phone, mobile phone, cell phone, voice over IP (VoIP) phone, wireless local loop phone, desktop computer, personal digital assistant (PDA), wireless cameras, gaming console or device, music storage device, playback appliance, wearable terminal device, wireless endpoint, mobile station, tablet, laptop, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), smart device, wireless customer-premise equipment (CPE), vehicle-mounted or vehicle embedded / integrated wireless device, etc. Other examples include any UE identified by the 3rd Generation Partnership Project (3 GPP), including a narrow band internet of things (NB-IoT) UE, a machine type communication (MTC) UE, and / or an enhanced MTC (eMTC) UE.

[0115] A UE may support device-to-device (D2D) communication, for example by implementing a 3GPP standard for sidelink communication, Dedicated Short-Range Communication (DSRC), vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), or vehicle- to-everything (V2X). In other examples, a UE may not necessarily have a user in the sense of a human user who owns and / or operates the relevant device. Instead, a UE may represent a device that is intended for sale to, or operation by, a human user but which may not, or whichmay not initially, be associated with a specific human user (e.g., a smart sprinkler controller). Alternatively, a UE may represent a device that is not intended for sale to, or operation by, an end user but which may be associated with or operated for the benefit of a user (e.g., a smart power meter).

[0116] The UE 200 includes processing circuitry 202 that is operatively coupled via a bus 204 to an input / output interface 206, a power source 208, a memory 210, a communication interface 212, and / or any other component, or any combination thereof. Certain UEs may utilize all or a subset of the components shown in FIGURE 6. The level of integration between the components may vary from one UE to another UE. Further, certain UEs may contain multiple instances of a component, such as multiple processors, memories, transceivers, transmitters, receivers, etc.

[0117] The processing circuitry 202 is configured to process instructions and data and may be configured to implement any sequential state machine operative to execute instructions stored as machine-readable computer programs in the memory 210. The processing circuitry 202 may be implemented as one or more hardware-implemented state machines (e.g., in discrete logic, field-programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), etc.); programmable logic together with appropriate firmware; one or more stored computer programs, general-purpose processors, such as a microprocessor or digital signal processor (DSP), together with appropriate software; or any combination of the above. For example, the processing circuitry 202 may include multiple central processing units (CPUs).

[0118] In the example, the input / output interface 206 may be configured to provide an interface or interfaces to an input device, output device, or one or more input and / or output devices. Examples of an output device include a speaker, a sound card, a video card, a display, a monitor, a printer, an actuator, an emitter, a smartcard, another output device, or any combination thereof. An input device may allow a user to capture information into the UE 200. Examples of an input device include a touch-sensitive or presence-sensitive display, a camera (e.g., a digital camera, a digital video camera, a web camera, etc.), a microphone, a sensor, a mouse, a trackball, a directional pad, a trackpad, a scroll wheel, a smartcard, and the like. The presence-sensitive display may include a capacitive or resistive touch sensor to sense input from a user. A sensor may be, for instance, an accelerometer, a gyroscope, a tilt sensor, a force sensor, a magnetometer, an optical sensor, a proximity sensor, a biometric sensor, etc., or any combination thereof. An output device may use the same type of interface port as an inputdevice. For example, a Universal Serial Bus (USB) port may be used to provide an input device and an output device.

[0119] In some embodiments, the power source 208 is structured as a battery or battery pack. Other types of power sources, such as an external power source (e.g., an electricity outlet), photovoltaic device, or power cell, may be used. The power source 208 may further include power circuitry for delivering power from the power source 208 itself, and / or an external power source, to the various parts of the UE 200 via input circuitry or an interface such as an electrical power cable. Delivering power may be, for example, for charging of the power source 208. Power circuitry may perform any formatting, converting, or other modification to the power from the power source 208 to make the power suitable for the respective components of the UE 200 to which power is supplied.

[0120] The memory 210 may be or be configured to include memory such as random access memory (RAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), magnetic disks, optical disks, hard disks, removable cartridges, flash drives, and so forth. In one example, the memory 210 includes one or more application programs 214, such as an operating system, web browser application, a widget, gadget engine, or other application, and corresponding data 216. The memory 210 may store, for use by the UE 200, any of a variety of various operating systems or combinations of operating systems.

[0121] The memory 210 may be configured to include a number of physical drive units, such as redundant array of independent disks (RAID), flash memory, USB flash drive, external hard disk drive, thumb drive, pen drive, key drive, high-density digital versatile disc (HD-DVD) optical disc drive, internal hard disk drive, Blu-Ray optical disc drive, holographic digital data storage (HDDS) optical disc drive, external mini-dual in-line memory module (DIMM), synchronous dynamic random access memory (SDRAM), external micro-DIMM SDRAM, smartcard memory such as tamper resistant module in the form of a universal integrated circuit card (UICC) including one or more subscriber identity modules (SIMs), such as a USIM and / or ISIM, other memory, or any combination thereof. The UICC may for example be an embedded UICC (eUICC), integrated UICC (iUICC) or a removable UICC commonly known as ‘SIM card.’ The memory 210 may allow the UE 200 to access instructions, application programs and the like, stored on transitory or non-transitory memory media, to off-load data, or to upload data. An article of manufacture, such as one utilizing a communication system may be tangiblyembodied as or in the memory 210, which may be or comprise a device-readable storage medium.

[0122] The processing circuitry 202 may be configured to communicate with an access network or other network using the communication interface 212. The communication interface 212 may comprise one or more communication subsystems and may include or be communicatively coupled to an antenna 222. The communication interface 212 may include one or more transceivers used to communicate, such as by communicating with one or more remote transceivers of another device capable of wireless communication (e.g., another UE or a network node in an access network). Each transceiver may include a transmitter 218 and / or a receiver 220 appropriate to provide network communications (e.g., optical, electrical, frequency allocations, and so forth). Moreover, the transmitter 218 and receiver 220 may be coupled to one or more antennas (e.g., antenna 222) and may share circuit components, software or firmware, or alternatively be implemented separately.

[0123] In the illustrated embodiment, communication functions of the communication interface 212 may include cellular communication, Wi-Fi communication, LPWAN communication, data communication, voice communication, multimedia communication, short-range communications such as Bluetooth, near-field communication, location-based communication such as the use of the global positioning system (GPS) to determine a location, another like communication function, or any combination thereof. Communications may be implemented in according to one or more communication protocols and / or standards, such as IEEE 802.11, Code Division Multiplexing Access (CDMA), Wideband Code Division Multiple Access (WCDMA), GSM, LTE, New Radio (NR), UMTS, WiMax, Ethernet, transmission control protocol / intemet protocol (TCP / IP), synchronous optical networking (SONET), Asynchronous Transfer Mode (ATM), QUIC, Hypertext Transfer Protocol (HTTP), and so forth.

[0124] Regardless of the type of sensor, a UE may provide an output of data captured by its sensors, through its communication interface 212, via a wireless connection to a network node. Data captured by sensors of a UE can be communicated through a wireless connection to a network node via another UE. The output may be periodic (e.g., once every 15 minutes if it reports the sensed temperature), random (e.g., to even out the load from reporting from several sensors), in response to a triggering event (e.g., when moisture is detected an alert is sent), inresponse to a request (e.g., a user initiated request), or a continuous stream (e.g., a live video feed of a patient).

[0125] As another example, a UE comprises an actuator, a motor, or a switch, related to a communication interface configured to receive wireless input from a network node via a wireless connection. In response to the received wireless input the states of the actuator, the motor, or the switch may change. For example, the UE may comprise a motor that adjusts the control surfaces or rotors of a drone in flight according to the received input or to a robotic arm performing a medical procedure according to the received input.

[0126] A UE, when in the form of an Internet of Things (loT) device, may be a device for use in one or more application domains, these domains comprising, but not limited to, city wearable technology, extended industrial application and healthcare. Non-limiting examples of such an loT device are a device which is or which is embedded in: a connected refrigerator or freezer, a TV, a connected lighting device, an electricity meter, a robot vacuum cleaner, a voice controlled smart speaker, a home security camera, a motion detector, a thermostat, a smoke detector, a door / window sensor, a flood / moisture sensor, an electrical door lock, a connected doorbell, an air conditioning system like a heat pump, an autonomous vehicle, a surveillance system, a weather monitoring device, a vehicle parking monitoring device, an electric vehicle charging station, a smart watch, a fitness tracker, a head-mounted display for Augmented Reality (AR) or Virtual Reality (VR), a wearable for tactile augmentation or sensory enhancement, a water sprinkler, an animal- or item-tracking device, a sensor for monitoring a plant or animal, an industrial robot, an Unmanned Aerial Vehicle (UAV), and any kind of medical device, like a heart rate monitor or a remote controlled surgical robot. A UE in the form of an loT device comprises circuitry and / or software in dependence of the intended application of the loT device in addition to other components as described in relation to the UE 200 shown in FIGURE 6.

[0127] As yet another specific example, in an loT scenario, a UE may represent a machine or other device that performs monitoring and / or measurements and transmits the results of such monitoring and / or measurements to another UE and / or a network node. The UE may in this case be an M2M device, which may in a 3GPP context be referred to as an MTC device. As one particular example, the UE may implement the 3GPP NB-IoT standard. In other scenarios, a UE may represent a vehicle, such as a car, a bus, a truck, a ship and an airplane, or otherequipment that is capable of monitoring and / or reporting on its operational status or other functions associated with its operation.

[0128] In practice, any number of UEs may be used together with respect to a single use case. For example, a first UE might be or be integrated in a drone and provide the drone’s speed information (obtained through a speed sensor) to a second UE that is a remote controller operating the drone. When the user makes changes from the remote controller, the first UE may adjust the throttle on the drone (e.g. by controlling an actuator) to increase or decrease the drone’s speed. The first and / or the second UE can also include more than one of the functionalities described above. For example, a UE might comprise the sensor and the actuator, and handle communication of data for both the speed sensor and the actuators.

[0129] FIGURE 7 shows a network node 300 in accordance with some embodiments. As used herein, network node refers to equipment capable, configured, arranged and / or operable to communicate directly or indirectly with a UE and / or with other network nodes or equipment, in a telecommunication network. Examples of network nodes include, but are not limited to, access points (APs) (e.g., radio access points), base stations (BSs) (e.g., radio base stations, Node Bs, evolved Node Bs (eNBs) and NR NodeBs (gNBs)).

[0130] Base stations may be categorized based on the amount of coverage they provide (or, stated differently, their transmit power level) and so, depending on the provided amount of coverage, may be referred to as femto base stations, pico base stations, micro base stations, or macro base stations. A base station may be a relay node or a relay donor node controlling a relay. A network node may also include one or more (or all) parts of a distributed radio base station such as centralized digital units and / or remote radio units (RRUs), sometimes referred to as Remote Radio Heads (RRHs). Such remote radio units may or may not be integrated with an antenna as an antenna integrated radio. Parts of a distributed radio base station may also be referred to as nodes in a distributed antenna system (DAS).

[0131] Other examples of network nodes include multiple transmission point (multi-TRP) 5G access nodes, multi-standard radio (MSR) equipment such as MSR BSs, network controllers such as radio network controllers (RNCs) or base station controllers (BSCs), base transceiver stations (BTSs), transmission points, transmission nodes, multi-cell / multicast coordination entities (MCEs), Operation and Maintenance (O&M) nodes, Operations Support System (OSS) nodes, Self-Organizing Network (SON) nodes, positioning nodes (e.g., Evolved Serving Mobile Location Centers (E-SMLCs)), and / or Minimization of Drive Tests (MDTs).

[0132] The network node 300 includes a processing circuitry 302, a memory 304, a communication interface 306, and a power source 308. The network node 300 may be composed of multiple physically separate components (e.g., a NodeB component and a RNC component, or a BTS component and a BSC component, etc.), which may each have their own respective components. In certain scenarios in which the network node 300 comprises multiple separate components (e.g., BTS and BSC components), one or more of the separate components may be shared among several network nodes. For example, a single RNC may control multiple NodeBs. In such a scenario, each unique NodeB and RNC pair, may in some instances be considered a single separate network node. In some embodiments, the network node 300 may be configured to support multiple radio access technologies (RATs). In such embodiments, some components may be duplicated (e.g., separate memory 304 for different RATs) and some components may be reused (e.g., a same antenna 310 may be shared by different RATs). The network node 300 may also include multiple sets of the various illustrated components for different wireless technologies integrated into network node 300, for example GSM, WCDMA, LTE, NR, WiFi, Zigbee, Z-wave, LoRaWAN, Radio Frequency Identification (RFID) or Bluetooth wireless technologies. These wireless technologies may be integrated into the same or different chip or set of chips and other components within network node 300.

[0133] The processing circuitry 302 may comprise a combination of one or more of a microprocessor, controller, microcontroller, central processing unit, digital signal processor, application-specific integrated circuit, field programmable gate array, or any other suitable computing device, resource, or combination of hardware, software and / or encoded logic operable to provide, either alone or in conjunction with other network node 300 components, such as the memory 304, to provide network node 300 functionality.

[0134] In some embodiments, the processing circuitry 302 includes a system on a chip (SOC). In some embodiments, the processing circuitry 302 includes one or more of radio frequency (RF) transceiver circuitry 312 and baseband processing circuitry 314. In some embodiments, the radio frequency (RF) transceiver circuitry 312 and the baseband processing circuitry 314 may be on separate chips (or sets of chips), boards, or units, such as radio units and digital units. In alternative embodiments, part or all of RF transceiver circuitry 312 and baseband processing circuitry 314 may be on the same chip or set of chips, boards, or units.

[0135] The memory 304 may comprise any form of volatile or non-volatile computer-readable memory including, without limitation, persistent storage, solid-state memory, remotely mounted memory, magnetic media, optical media, random access memory (RAM), read-only memory (ROM), mass storage media (for example, a hard disk), removable storage media (for example, a flash drive, a Compact Disk (CD) or a Digital Video Disk (DVD)), and / or any other volatile or non-volatile, non-transitory device-readable and / or computer-executable memory devices that store information, data, and / or instructions that may be used by the processing circuitry 302. The memory 304 may store any suitable instructions, data, or information, including a computer program, software, an application including one or more of logic, rules, code, tables, and / or other instructions capable of being executed by the processing circuitry 302 and utilized by the network node 300. The memory 304 may be used to store any calculations made by the processing circuitry 302 and / or any data received via the communication interface 306. In some embodiments, the processing circuitry 302 and memory 304 is integrated.

[0136] The communication interface 306 is used in wired or wireless communication of signaling and / or data between a network node, access network, and / or UE. As illustrated, the communication interface 306 comprises port(s) / terminal(s) 316 to send and receive data, for example to and from a network over a wired connection. The communication interface 306 also includes radio front-end circuitry 318 that may be coupled to, or in certain embodiments a part of, the antenna 310. Radio front-end circuitry 318 comprises filters 320 and amplifiers 322. The radio front-end circuitry 318 may be connected to an antenna 310 and processing circuitry 302. The radio front-end circuitry may be configured to condition signals communicated between antenna 310 and processing circuitry 302. The radio front-end circuitry 318 may receive digital data that is to be sent out to other network nodes or UEs via a wireless connection. The radio front-end circuitry 318 may convert the digital data into a radio signal having the appropriate channel and bandwidth parameters using a combination of filters 320 and / or amplifiers 322. The radio signal may then be transmitted via the antenna 310. Similarly, when receiving data, the antenna 310 may collect radio signals which are then converted into digital data by the radio front-end circuitry 318. The digital data may be passed to the processing circuitry 302. In other embodiments, the communication interface may comprise different components and / or different combinations of components.

[0137] In certain alternative embodiments, the network node 300 does not include separate radio front-end circuitry 318, instead, the processing circuitry 302 includes radio front-end circuitry and is connected to the antenna 310. Similarly, in some embodiments, all or some of the RF transceiver circuitry 312 is part of the communication interface 306. In still other embodiments, the communication interface 306 includes one or more ports or terminals 316, the radio front-end circuitry 318, and the RF transceiver circuitry 312, as part of a radio unit (not shown), and the communication interface 306 communicates with the baseband processing circuitry 314, which is part of a digital unit (not shown).

[0138] The antenna 310 may include one or more antennas, or antenna arrays, configured to send and / or receive wireless signals. The antenna 310 may be coupled to the radio front-end circuitry 318 and may be any type of antenna capable of transmitting and receiving data and / or signals wirelessly. In certain embodiments, the antenna 310 is separate from the network node 300 and connectable to the network node 300 through an interface or port.

[0139] The antenna 310, communication interface 306, and / or the processing circuitry 302 may be configured to perform any receiving operations and / or certain obtaining operations described herein as being performed by the network node. Any information, data and / or signals may be received from a UE, another network node and / or any other network equipment. Similarly, the antenna 310, the communication interface 306, and / or the processing circuitry 302 may be configured to perform any transmitting operations described herein as being performed by the network node. Any information, data and / or signals may be transmitted to a UE, another network node and / or any other network equipment.

[0140] The power source 308 provides power to the various components of network node 300 in a form suitable for the respective components (e.g., at a voltage and current level needed for each respective component). The power source 308 may further comprise, or be coupled to, power management circuitry to supply the components of the network node 300 with power for performing the functionality described herein. For example, the network node 300 may be connectable to an external power source (e.g., the power grid, an electricity outlet) via an input circuitry or interface such as an electrical cable, whereby the external power source supplies power to power circuitry of the power source 308. As a further example, the power source 308 may comprise a source of power in the form of a battery or battery pack which is connected to, or integrated in, power circuitry. The battery may provide backup power should the external power source fail.

[0141] Embodiments of the network node 300 may include additional components beyond those shown in FIGURE 7 for providing certain aspects of the network node’s functionality, including any of the functionality described herein and / or any functionality necessary to support the subject matter described herein. For example, the network node 300 may include user interface equipment to allow input of information into the network node 300 and to allow output of information from the network node 300. This may allow a user to perform diagnostic, maintenance, repair, and other administrative functions for the network node 300.

[0142] FIGURE 8 is a flowchart illustrating an example method 800 in a network node, according to certain embodiments. In particular embodiments, one or more steps of FIGURE 8 may be performed by network node 300 described with respect to FIGURE 7. The network node is capable of mitigating interference in a wireless network.

[0143] The method begins at step 812, where the network node (e.g., network node 300) receives a reference signal configuration. The reference signal configuration comprises an indication of time and frequency resources for receiving one or more reference signals from a second network node. The network node may receive the reference signal configuration from the second network node, or a third network node, such as an 0AM node. In particular embodiments, the network node receives the reference signal configuration according to any of the embodiments and examples described herein.

[0144] In particular embodiments, the one or more reference signals comprise one or more SSBs. In particular embodiments, the reference signal configuration further comprises an indication of a SBFD configuration for the second network node. The reference signal configuration may comprise an indication of an uplink / downlink timing offset for the second network node. In particular embodiments, the reference signal configuration comprises any of the reference signal configurations described with respect to the embodiments and examples described herein.

[0145] At step 814, the network node measures one or more reference signals transmitted from the second network node according to the reference signal configuration. The network node may measure the reference signals according to any of the embodiments and examples described above.

[0146] At step 816, the network node reports, to a third network node, a channel estimate for the second network node-to-first network node channel based on the measured one or morereference signals. The third network node may be the same as the second network node, or may be a different network node.

[0147] The network node may report the channel estimate(s) according to any of the embodiments and examples described herein. The third network node may use the reported channel estimates to determine aggressor / victim network nodes.

[0148] At step 818, the network node may transmit a request for interference mitigation to the third network node, the request based on the measured one or more reference signals. For example, based on the measured reference signals, the network node may determine aggressor / victim network nodes, and may transmit a request for mitigation accordingly. The network node may transmit the request according to any of the embodiments and examples described herein.

[0149] At step 820, the network node may receive a request for interference mitigation from the third network node, the request based on the reported channel estimate. For example, based on the reporting sent by the network node, the third network node may determine aggressor / victim network nodes, and transmit a request for mitigation to the network node. The network node may receive the request according to any of the embodiments and examples described herein.

[0150] Modifications, additions, or omissions may be made to method 800 of FIGURE 8. Additionally, one or more steps in the method of FIGURE 8 may be performed in parallel or in any suitable order.

[0151] FIGURE 9 is a flowchart illustrating another example method 900 in a network node, according to certain embodiments. In particular embodiments, one or more steps of FIGURE 9 may be performed by network node 300 described with respect to FIGURE 7. The network node is capable of mitigating interference in a wireless network.

[0152] The method begins at step 912, where the network node (e.g., network node 300) transmits a reference signal configuration to a first network node. The reference signal configuration comprises an indication of time and frequency resources the second network node will use for transmitting one or more reference signals. In particular embodiments, the network node transmits the reference signal configuration according to any of the embodiments and examples described herein.

[0153] The reference signal configuration is descried in more detail with respect to FIGURE 8 and with respect to the embodiments and examples described herein.

[0154] At step 914, the network node transmits one or more reference signals according to the reference signal configuration. The network node transmits the one or more reference signals according to any of the embodiments and examples described herein.

[0155] At step 916, the network node receives , from the first network node, a channel estimate for the second network node-to-first network node channel based on the transmitted one or more reference signals. The network node may use the reported channel estimate(s) to determine aggressor / victim network nodes.

[0156] At step 918, the network node may transmit a request for interference mitigation to the first network node, the request based on the received channel estimate. The network node may transmit the request according to any of the embodiments and examples described herein.

[0157] At step 920, the network node may receive a request for interference mitigation from the first network node, the request based on the transmitted one or more reference signals. The network node may receive the request according to any of the embodiments and examples described herein.

[0158] Modifications, additions, or omissions may be made to method 900 of FIGURE 9. Additionally, one or more steps in the method of FIGURE 9 may be performed in parallel or in any suitable order.

[0159] The foregoing description sets forth numerous specific details. It is understood, however, that embodiments may be practiced without these specific details. In other instances, well-known circuits, structures and techniques have not been shown in detail in order not to obscure the understanding of this description. Those of ordinary skill in the art, with the included descriptions, will be able to implement appropriate functionality without undue experimentation.

[0160] References in the specification to “one embodiment,” “an embodiment,” “an example embodiment,” etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to implement such feature, structure, or characteristic in connection with other embodiments, whether or not explicitly described.

[0161] Although this disclosure has been described in terms of certain embodiments, alterations and permutations of the embodiments will be apparent to those skilled in the art. Accordingly, the above description of the embodiments does not constrain this disclosure. Other changes, substitutions, and alterations are possible without departing from the scope of this disclosure, as defined by the claims below.

[0162] Some example embodiments are described below.Group A Embodiments1. A method performed by a user equipment for mitigating interference in a mobile network, the method comprising: receiving a request to obtain a global identity of each network node in a list of aggressor network nodes based at least on a received set of signal strengths; and transmitting a report comprising signal measurements on the received set of signal strengths.2. A method performed by a wireless device, the method comprising:- any of the wireless device steps, features, or functions described above, either alone or in combination with other steps, features, or functions described above.3. The method of the previous embodiment, further comprising one or more additional wireless device steps, features or functions described above.4. The method of any of the previous embodiments, further comprising:- providing user data; and- forwarding the user data to a host computer via the transmission to the base station.Group B Embodiments5. A method performed by a network node for mitigating interference in a mobile network, the method comprising: exchanging resource information with one or more first network nodes, wherein the resource information indicates a set of predetermined time and frequency resources over which a reference signal is transmitted by one or more second network nodes, wherein the one or more second network nodes comprise the network node; transmitting, to one or more first network nodes, the reference signal during apredetermined slot in the set of predetermined time and frequency resources, wherein the one or more first network nodes are designated to listen for the reference signal.6. The method of embodiment 6, wherein the resource information comprises a type of the reference signal, wherein the type of the reference signal comprises a demodulation reference signal (DMRS).7. The method of any one of the embodiments 6-7, wherein the set of predetermined time and frequency resources is specified in a configuration provided by an operation, administration, and maintenance (OAM).8. The method of any one the embodiments 6-8, wherein reference signal is received at the one or more first network nodes during a second predetermined slot in the set of predetermined time and frequency resources.9. A method performed by a network node for mitigating interference in a mobile network, the method comprising: determining that a performance of an uplink (UL) transmission is affected by an interference; identifying a list of aggressor network nodes to transmit a reference signal; establishing or utilizing an interface with the identified aggressor network nodes for inter-node communication and Co-Channel Interference (CLI) coordination; transmitting signaling information that indicates a set of time and frequency resources on which to monitor the reference signals to reduce CLI.10. The method embodiment 10, wherein identifying the list of aggressor network nodes is in response to: transmitting a request to a set of network nodes to send reference signals; receiving a set of reference signal from the se of network nodes; and identifying the list of aggressor network nodes based on the received set of signalstrengths from the set of network nodes.11. The method of any one of the embodiments 10-11, further comprising: transmitting a request to one or more victim user equipment (UEs) to obtain a global identity of the identified list of aggressor network nodes based at least on the received set of signal strengths; and receiving a report comprising signal measurements on the received set of signal strengths; and confirming the list of aggressor network nodes based on the report.12. The method of any one the embodiments 10-12, wherein identifying the list of aggressor network nodes is in response to sending a request to a local or a central control nodes and receiving the list.13. The method of any one the embodiments 10-13, wherein identifying the list of aggressor network nodes is a neighbor-cell list obtained from information element (IE) new radio (NR).14. The method of any one the embodiments 10-14, wherein identifying the list of aggressor network nodes is received by an operation, administration, and maintenance (0AM) system.15. A method performed by a victim network node for mitigating interference in a mobile network, the method comprising: transmitting a reference signal in a slot with predetermined time and frequency resources to facilitate interference measurement by neighboring cells.16. The method of the embodiment 16, wherein the reference signal is transmitted periodically with a predefined periodicity.17. The method of any one the embodiments 16-17, wherein the reference signal is transmitted periodically in synchronization to synchronization signal block (SSB) or periodic / semi-persistent channel state information reference signals (CSI-RS) transmissions.18. The method of any one the embodiments 16-18, wherein the predetermined time and frequency resources are provided by an operation, administration, and maintenance (OAM).19. A method performed by an aggressor network node for mitigating interference in a mobile network, the method comprising: transmitting a reference signal in a given slot with predetermined time and frequency resources to enable interference measurement by neighboring cells;20. The method of any one the embodiments 19-20, wherein the reference signal is transmitted periodically in synchronization to synchronization signal block (SSB) or periodic / semi-persistent channel state information reference signals (CSI-RS) transmissions.21. The method of any one the embodiments 19-21, wherein the predetermined time and frequency resources are provided by an operation, administration, and maintenance (OAM).22. A method performed by a network node for mitigating interference in a mobile network, the method comprising: configuring one or more types of a set of reference signals for co-channel interference (CLI) mitigation, wherein the one or more types of the set of reference signals comprises: a periodic channel state information-reference signal (CSI-RS); a physical downlink control channel (PDCCH); a physical downlink shared channel (PDSCH); a synchronization signal blocks (SSB); a demodulation reference signal (DMRS); ora new periodic signal based on existing reference signals; transmitting a configuration of the set of reference signals to neighboring network nodes to enable correct reception and to facilitate a gNB-gNB channel estimation; and exchanging information with the neighboring network nodes regarding time and frequency resources for transmission of the set of reference signals and resource muting.23. The method of the embodiment 23, wherein configuring the one or more types of the set of reference signals for CLI mitigation, comprises: estimating a gNB-gNB channel between the network node and at least a second network node from among the neighboring network nodes based on a used type from among the one or more types of the set of reference signals.24. The method of any one of the embodiments 23-24, wherein configuring the one or more types of the set of reference signals for CLI mitigation, comprises: selecting a first SSB that has a stronger power level compared to other SSBs for the gNB-gNB channel estimation; and applying a nulling precoder based on individual or averaged channel measurements.25. The method of any one the embodiments 23-25, wherein each of the set of reference signals is transmitted periodically in synchronization to synchronization signal block (SSB) or periodic / semi-persistent channel state information reference signals (CSI-RS) transmissions.26. The method of any one the embodiments 23-26, wherein the time and frequency resources are provided by an operation, administration, and maintenance (OAM).27. A method performed by a network node for interference mitigation in a mobile network, the method comprising: transmitting a set of reference signals in a round-robin fashion across one or more cells; and transmitting a periodicity of the set of reference signals to the one or more cells.28. The method of the embodiment 28, further comprising receiving a configuration for the periodicity of the set of reference signals from an operation, administration, and maintenance (0AM) system, wherein the configuration specifies the periodicity of each of the reference signals for each of the one or more cells.29. A method performed by a network node for interference mitigation in a mobile network, the method comprising: identifying a cell identity (ID) for a cell associated with the network node; determining a slot number for transmitting a reference signal based on the identified cell ID, wherein the determination comprises determining the slot number as a modulus of the cell ID and a predetermined number of slots in a radio frame; and transmitting the reference signal in the determined slot number.30. The method of the embodiment 30, further comprising: determining a system frame number (SFN) for transmitting the reference signal, the determination is based on the cell ID of the cell, wherein the reference signal is transmitted within the determined SFN.31. The method of any one of the embodiments 30-31 , further comprising: transmitting a periodicity of the reference signal to one or more cells participating in a coordinated linear interference (CLI) mitigation.32. The method of any one of the embodiments 30-32, further comprising receiving a configuration for a periodicity of reference signal from an operation, administration, and maintenance (0AM) system, wherein the configuration specifies the periodicity of each reference signal for each cell participating in a coordinated linear interference (CLI) mitigation.33. A method performed by a victim network node for interference mitigation in a mobile network, the method comprising: exchanging a reference signal configuration comprising a periodicity, and time and frequency resources with one or more network nodes; transmitting a request to an aggressor network node to perform a transmission (Tx) nulling toward the victim network node, wherein the request comprises a time duration for the Tx nulling; transmitting information related to a reference signal configuration to the aggressor network node, wherein the information comprises the time and frequency resources and parameters to determine a sequence of the reference signal; receiving a confirmation of the Tx nulling from the aggressor network node; performing a channel estimation; and transmitting the channel estimation to the aggressor network node to determine a precoder for the Tx nulling.34. A method performed by an aggressor network node for interference mitigation in a mobile network, the method comprising: receiving a request from a victim network node to perform a transmission (Tx) nulling toward the victim network node, wherein the request comprises a time duration for the Tx nulling; transmitting information related to a reference signal configuration to the victim network node, wherein the information comprises the time and frequency resources and parameters to determine a sequence of the reference signal; transmitting a confirmation of the Tx nulling to the victim network node; receiving a channel estimation from the victim network node; and determining a precoder for the Tx nulling.35. A method performed by an aggressor network node for interference mitigation in amobile network, the method comprising: transmitting a request to a victim network node to perform a channel measurement toward the aggressor network node, wherein the request comprises information regarding a reference signal to be transmitted by the aggressor network node for the purpose of enabling the victim network node to perform the channel measurement, the information comprising time and frequency resources and parameters for determining a sequence of the reference signal; transmitting the reference signal to the victim network node; receiving a channel estimate from the victim network node based on the transmitted reference signal; determining a nulling precoder directed towards the victim network node based on the received channel estimate.36. The method of the embodiment 36, receiving a confirmation that the victim network node agrees to be nulled, wherein the confirmation comprises a time interval during which the victim network node is to be nulled.37. A method performed by a victim network node for interference mitigation in a mobile network, the method comprising: performing a channel estimation, wherein the channel estimation is related to a channel between the victim network node and an aggressor network node causing an interference on signals of the victim network node; generating a channel report based on the channel estimation, wherein the channel report comprises information derived from at least a portion of the channel estimation; transmitting the channel report to the aggressor network node, wherein a nulling precoder is determined based on the channel report.38. The method of the embodiment 38, further comprising: applying a set of predetermined precoders to perform the channel estimation; selecting a first precoder that results in a larger received power compared to other precoders from among the set of predetermined precoders; andincluding in the channel report an indication of the selected precoder and the associated received power.39. The method of the embodiment 39, wherein the set of predetermined precoders is: fixed in a network specification; or sent by the aggressor network node in the request for a channel measurement.40. The method of any one of the embodiments 38-40, further comprising performing channel compression before transmitting the channel report, wherein the channel compression is executed using an autoencoder.41. The method of any one of the embodiments 38-41, further comprising: performing a singular value decomposition (SVD) or eigenvalue decomposition of a channel covariance matrix; and transmitting the decomposition results as the channel report to the aggressor network node, wherein the channel report comprises an N larger singular values or eigenvalues and associated eigenvectors.42. A method performed by a network node for interference mitigation in a mobile network, the method comprising: transmitting, to one or more network nodes participating in coordinated linear interference (CLI) mitigation process, timing information for transmission of a sequence of reference signals, wherein the timing information comprises: a time offset from an absolute time reference to the start of the transmission of the first reference signal in the sequence; and a representation of the time between consecutive reference signals and the frequency resources for each transmitted reference signal; receiving, from the one or more network nodes, timing information related to their radio frame and subframe transmissions, and timing of sequences of reference signals;43. The method of the embodiment 43, wherein the timing information comprises: a pattern of muted resources for each cell where muting is applied; a time offset from an absolute time reference to the start of a first muted resource; and a representation of the time between consecutive muted resources and frequency resources for each muted resource;44. The method of any one of the embodiments 43-44, further comprising: exchanging, with the one or more network nodes, information about uplink / downlink (UL / DL) timing offset for each cell; determining, based on a received UL / DL timing offsets from one or more network nodes, which cell(s) and network node(s) is be excluded from the CLI mitigation process based on a threshold criteria for the UL / DL timing offset; selecting, based on the exchange of UL / DL timing offset information, a first CLI mitigation technique; and performing the first CLI mitigation technique.45. The method of any one of the embodiments 43-45, further comprising adjusting a transmission schedule based on the received timing information, wherein the transmission schedule comprises a schedule of reference signal transmissions and a schedule of resource muting.46. A method performed by a base station, the method comprising:- any of the steps, features, or functions described above with respect to base station, either alone or in combination with other steps, features, or functions described above.47. The method of the previous embodiment, further comprising one or more additional base station steps, features or functions described above.48. The method of any of the previous embodiments, further comprising:- obtaining user data; and- forwarding the user data to a host computer or a wireless device.Group C Embodiments49. A user equipment for mitigating interference in a mobile network, comprising: processing circuitry configured to perform any of the steps of any of the Group A embodiments; and power supply circuitry configured to supply power to the processing circuitry.50. A network node for mitigating interference in a mobile network, the network node comprising: processing circuitry configured to perform any of the steps of any of the Group B embodiments; power supply circuitry configured to supply power to the processing circuitry.51. A user equipment (UE) for mitigating interference in a mobile network, the UE comprising: an antenna configured to send and receive wireless signals; radio front-end circuitry connected to the antenna and to processing circuitry, and configured to condition signals communicated between the antenna and the processing circuitry; the processing circuitry being configured to perform any of the steps of any of the Group A embodiments; an input interface connected to the processing circuitry and configured to allow input of information into the UE to be processed by the processing circuitry; an output interface connected to the processing circuitry and configured to output information from the UE that has been processed by the processing circuitry; and a battery connected to the processing circuitry and configured to supply power to the UE.

Claims

CLAIMS:

1. A method performed by a first network node for mitigating interference in a wireless network, the method comprising: receiving (812) a reference signal configuration, the reference signal configuration comprising an indication of time and frequency resources for receiving one or more reference signals from a second network node; measuring (814) one or more reference signals transmitted from the second network node according to the reference signal configuration; and reporting (816), to a third network node, a channel estimate for the second network node-to-first network node channel based on the measured one or more reference signals.

2. The method of claim 1, further comprising transmitting (818) a request for interference mitigation to the third network node, the request based on the measured one or more reference signals.

3. The method of claim 1, further comprising receiving (820) a request for interference mitigation from the third network node, the request based on the reported channel estimate.

4. The method of any one of claims 1 -3, wherein the one or more reference signals comprise one or more synchronization signal blocks, SSBs.

5. The method of any one of claims 1 -4, wherein the reference signal configuration further comprises an indication of a subband full duplex, SBFD, configuration for the second network node.

6. The method of any one of claims 1 -5, wherein the reference signal configuration further comprises an indication of an uplink / downlink timing offset for the second network node.

7. The method of any one of claims 1-6, wherein the first network node comprisesa victim network node and one of the second network node and the third network node comprise an aggressor network node.

8. The method of any one of claims 1-6, wherein the first network node comprises an aggressor network node and the second network node comprises a victim network node.

9. The method of any one of claims 1-8, wherein the reference signal configuration is received from the second network node or the third network node.

10. The method of any one of claims 1-9, wherein the third network node is the same network node as the second network node.

11. The method of any one of claims 1 -9, wherein the third network node comprises an operations, administration, and maintenance, 0AM, network node.

12. A first network node (300) capable of mitigating interference in a wireless network, the network node comprising processing circuitry (302) operable to: receive a reference signal configuration, the reference signal configuration comprising an indication of time and frequency resources for receiving one or more reference signals from a second network node; measure one or more reference signals transmitted from the second network node according to the reference signal configuration; and report, to a third network node, a channel estimate for the second network node-to-first network node channel based on the measured one or more reference signals.

13. The network node of claim 12, the processing circuitry further operable to: transmit a request for interference mitigation to the third network node, the request based on the measured one or more reference signals; or receive a request for interference mitigation from the third network node, the request based on the reported channel estimate.

14. The network node of any one of claims 12-13, wherein the one or morereference signals comprise one or more synchronization signal blocks, SSBs.

15. The network node of any one of claims 12-14, wherein the reference signal configuration further comprises an indication of a subband full duplex, SBFD, configuration for the second network node.

16. The network node of any one of claims 12-15, wherein the reference signal configuration further comprises an indication of an uplink / downlink timing offset for the second network node.

17. The network node of any one of claims 12-16, wherein: the first network node comprises a victim network node and one of the second network node and the third network node comprise an aggressor network node; or the first network node comprises an aggressor network node and the second network node comprises a victim network node.

18. A method performed by a second network node for mitigating interference in a wireless network, the method comprising: transmitting (912) a reference signal configuration to a first network node, the reference signal configuration comprising an indication of time and frequency resources the second network node will use for transmitting one or more reference signals; transmitting (914) one or more reference signals according to the reference signal configuration; and receiving (916), from the first network node, a channel estimate for the second network node-to-first network node channel based on the transmitted one or more reference signals.

19. The method of claim 18, further comprising transmitting (918) a request for interference mitigation to the first network node, the request based on the received channel estimate.

20. The method of claim 18, further comprising receiving (920) a request for interference mitigation from the first network node, the request based on the transmitted oneor more reference signals.

21. The method of any one of claims 18-20, wherein the one or more reference signals comprise one or more synchronization signal blocks, SSBs.

22. The method of any one of claims 18-21, wherein the reference signal configuration further comprises an indication of a subband full duplex, SBFD, configuration for the second network node.

23. The method of any one of claims 18-22, wherein the reference signal configuration further comprises an indication of an uplink / downlink timing offset for the second network node.

24. The method of any one of claims 18-23, wherein the first network node comprises a victim network node and the second network node comprises an aggressor network node.

25. The method of any one of claims 18-23, wherein the first network node comprises an aggressor network node and the second network node comprises a victim network node.

26. A second network node (300) capable of mitigating interference in a wireless network, the network node comprising processing circuitry (302) operable to: transmit a reference signal configuration to a first network node, the reference signal configuration comprising an indication of time and frequency resources the second network node will use for transmitting one or more reference signals; transmit one or more reference signals according to the reference signal configuration; and receive, from the first network node, a channel estimate for the second network node- to-first network node channel based on the transmitted one or more reference signals.

27. The network node of claim 26, the processing circuitry further operable totransmit a request for interference mitigation to the first network node, the request based on the received channel estimate.

28. The network node of claim 26, the processing circuitry further operable to receive a request for interference mitigation from the first network node, the request based on the transmitted one or more reference signals.

29. The network node of any one of claims 26-28, wherein the one or more reference signals comprise one or more synchronization signal blocks, SSBs.

30. The network node of any one of claims 26-29, wherein the reference signal configuration further comprises an indication of a subband full duplex, SBFD, configuration for the second network node.

31. The network node of any one of claims 26-30, wherein the reference signal configuration further comprises an indication of an uplink / downlink timing offset for the second network node.

32. The network node of any one of claims 26-31, wherein the first network node comprises a victim network node and the second network node comprises an aggressor network node.

33. The network node of any one of claims 26-31, wherein the first network node comprises an aggressor network node and the second network node comprises a victim network node.

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