Interference management

Abstract

According to an example aspect of the present invention, there is provided an apparatus configured to provide to a network an indication that at least one triggering condition has been determined to be met in the apparatus, the at least one triggering condition relating to a reduction in multiple input multiple output, MIMO, layers in use on a bandwidth part the apparatus is using, reduce a number of MIMO layers in use in the apparatus to thereby release at least one resource of the apparatus, and use the at least one released resource to perform interference reduction on an interfering signal received by the apparatus.

Description

INTERFERENCE MANAGEMENTFIELD

[0001] The present disclosure relates to the field of wireless communication.BACKGROUND

[0002] A wireless receiver may be impaired as to its operation by interference. Interference may affect reception in several different ways, for example in systems based on code division multiple access, CDMA, other users are active in the same frequency resources at the same time, increasing a base level of interference. Similar co-channel interference may exist in other systems, e.g. due to frequency reuse in cellular systems or multiple WiFi (IEEE 802.11) networks operating on the same channel(s). Adjacent-channel leakage may cause interference to adjacent frequencies due to poor tuning of radio frequency components or malfunctioning radio frequency components. Harmonic emissions of a radio transmitter may also cause interference outside an operational frequency band of the radio transmitter.

[0003] Various ways to mitigate the effects of interference have been proposed, such as limiting re-use of frequencies to geographically distant devices, requiring use of filters which reduce adjacent-channel energy leakage and designing fast power control loops which enable CDMA-based systems to avoid transmitting at power levels which are unnecessarily high.SUMMARY

[0004] According to some aspects, there is provided the subject-matter of the independent claims. Some embodiments are defined in the dependent claims. The scope of protection sought for various embodiments of the invention is set out by the independent claims. The embodiments, examples and features, if any, described in this specification that do not fall under the scope of the independent claims are to be interpreted as examples useful for understanding various embodiments of the invention.

[0005] According to a first aspect of the present disclosure, there is provided an apparatus comprising at least one processing core and at least one memory storing instructions that, when executed by the at least one processing core, cause the apparatus at least to provide to a network an indication that at least one triggering condition has been determined to be met in the apparatus, the at least one triggering condition relating to a reduction in multiple input multiple output, MIMO, layers in use on a bandwidth part the apparatus is using, reduce a number of MIMO layers in use in the apparatus to thereby release at least one resource of the apparatus, and use the at least one released resource to perform interference reduction on an interfering signal received by the apparatus.

[0006] According to a second aspect of the present disclosure, there is provided an apparatus comprising at least one processing core and at least one memory storing instructions that, when executed by the at least one processing core, cause the apparatus at least to receive from a user equipment an indication that at least one triggering condition has been determined to be met in the user equipment, the at least one triggering condition relating to a reduction in multiple input multiple output, MIMO, layers in use on a bandwidth part the user equipment is using, the reduction being to release a resource for interference reduction, and reduce a number of MIMO layers in use in the apparatus in communication with the user equipment to thereby release at least one resource of the user equipment for interference reduction.

[0007] According to a third aspect of the present disclosure, there is provided a method comprising providing, from an apparatus, to a network an indication that at least one triggering condition has been determined to be met in the apparatus, the at least one triggering condition relating to a reduction in multiple input multiple output, MIMO, layers in use on a bandwidth part the apparatus is using, reducing a number of MIMO layers in use in the apparatus to thereby release at least one resource of the apparatus, and using the at least one released resource to perform interference reduction on an interfering signal received by the apparatus.

[0008] According to a fourth aspect of the present disclosure, there is provided a method comprising receiving, in an apparatus, from a user equipment an indication that at least one triggering condition has been determined to be met in the user equipment, the at least one triggering condition relating to a reduction in multiple input multiple output, MIMO, layers in use on a bandwidth part the user equipment is using, and reducing a numberof MIMO layers in use in the apparatus in communication with the user equipment to thereby release at least one resource of the user equipment for interference reduction.

[0009] According to a fifth aspect of the present disclosure, there is provided an apparatus comprising means for providing to a network an indication that at least one triggering condition has been determined to be met in the apparatus, the at least one triggering condition relating to a reduction in multiple input multiple output, MIMO, layers in use on a bandwidth part the apparatus is using, reducing a number of MIMO layers in use in the apparatus to thereby release at least one resource of the apparatus, and using the at least one released resource to perform interference reduction on an interfering signal received by the apparatus.

[0010] According to a sixth aspect of the present disclosure, there is provided an apparatus comprising means for receiving from a user equipment an indication that at least one triggering condition has been determined to be met in the user equipment, the at least one triggering condition relating to a reduction in multiple input multiple output, MIMO, layers in use on a bandwidth part the user equipment is using, the reduction being to release a resource for interference reduction, and reducing a number of MIMO layers in use in the apparatus in communication with the user equipment to thereby release at least one resource of the user equipment for interference reduction.

[0011] According to a seventh aspect of the present disclosure, there is provided a non-transitory computer readable medium having stored thereon a set of computer readable instructions that, when executed by at least one processor, cause an apparatus to at least provide to a network an indication that at least one triggering condition has been determined to be met in the apparatus, the at least one triggering condition relating to a reduction in multiple input multiple output, MIMO, layers in use on a bandwidth part the apparatus is using, reduce a number of MIMO layers in use in the apparatus to thereby release at least one resource of the apparatus, and use the at least one released resource to perform interference reduction on an interfering signal received by the apparatus.

[0012] According to an eighth aspect of the present disclosure, there is provided a non-transitory computer readable medium having stored thereon a set of computer readable instructions that, when executed by at least one processor, cause an apparatus to at least receive from a user equipment an indication that at least one triggering condition has been determined to be met in the user equipment, the at least one triggering condition relating toa reduction in multiple input multiple output, MIMO, layers in use on a bandwidth part the user equipment is using, the reduction being to release a resource for interference reduction, and reduce a number of MIMO layers in use in the apparatus in communication with the user equipment to thereby release at least one resource of the user equipment for interference reduction.BRIEF DESCRIPTION OF THE DRAWINGS

[0013] FIGURE 1 illustrates an example system in accordance with at least some embodiments of the present invention;

[0014] FIGURE 2A illustrates an example spectrum in accordance with at least some embodiments of the present invention;

[0015] FIGURE 2B illustrates an example signalling sequence in accordance with at least some embodiments of the present invention;

[0016] FIGURE 3 illustrates an example apparatus capable of supporting at least some embodiments of the present invention;

[0017] FIGURE 4 illustrates signalling in accordance with at least some embodiments of the present invention;

[0018] FIGURE 5 is a flow graph of a method in accordance with at least some embodiments of the present invention, and

[0019] FIGURE 6 is a flow graph of a method in accordance with at least some embodiments of the present invention.EMBODIMENTS

[0020] Methods are described herein which enable a wireless communication device, such as a user equipment, UE, of a cellular communication system, to adapt to the presence of an interfering signal by reducing a number of multiple input multiple output, MIMO, layers in that the UE may use the released resource to perform interference reduction on the interfering signal. Signalling with the network is herein described which enables the networkto co-operate in the process and, in some embodiments, to control the process. The interference reduction performed by the wireless communication device may comprise phasing out or nulling of the interfering signal, at least in part, for example by performing spatial domain processing.

[0021] FIGURE 1 illustrates an example system in accordance with at least some embodiments of the present invention. This system includes base stations 130, 135 in communication with UEs, such as UE 110. A radio link connects base station 130 with UE 110, The radio link may be bidirectional, comprising an uplink, UL, to convey information from UE 110 toward base station 130 and a downlink, DL, to convey information from the base station 130 toward UE 110. A cellular communication system may comprise hundreds or thousands of base stations, of which only two are illustrated in FIGURE 1 for the sake of clarity of the illustration. The base stations may be distributed in that they comprise a centralized unit, CU, and one or more distributed unit, DU.

[0022] Base station 130 is further coupled communicatively with core network node 140, which may comprise, for example, a mobility management entity, MME, or access and mobility management function, AMF. The core network node 140 may be coupled with further core network nodes, and with a network 150, which may comprise the Internet or a corporate network, for example. The system may communicate with further networks via network 150. Examples of the further core network nodes, which are not illustrated in FIGURE 1 for the sake of clarity, include gateways and subscriber information repositories. Core network nodes may be virtualized in the sense that they may run as software modules on computing substrates, such that more than one virtualized network node may run on a same computing substrate. The network may be configured to function in accordance with a suitable cellular standard such as long term evolution, LTE, fifth generation, 5G, which is also known as New Radio, NR, or sixth generation, 6G standards as defined by the the 3rdgeneration partnership project, 3GPP. To obtain interoperation, UEs attaching to the network are configured to support a same standard as the network. For example, a radio access technology, RAT, in use between UE 110 and base station 130, 135, such as in 5G or 6G, may be based on orthogonal frequency division multiplexing, OFDM.

[0023] Base station 130 controls, in the example of FIGURE 1 cells 130A and 130B, of which UE 110 is in the situation illustrated in FIGURE 1 attached with cell 130A, and base station 135 controls, in the example of FIGURE 1, cells 135A and 135B. The numberof cells, or beams, may be in excess of what is illustrated in FIGURE 1. It is also possible that a base station has a single cell or beam. While illustrated as sector-shaped, cells of a same base station may be omnidirectional and operate on different frequencies or frequency bands, for example. A mobility event may comprise a switch from one beam to another beam of the same cell, or a switch from one cell to another cell. To support mobility procedures, UEs, including UE 110, are configured to conduct mobility measurements to measure signal strengths of adjacent beams and / or cells, and report results of these measurements to the network, which may then take a decision concerning a mobility event, such as a beam change or a cell switch.

[0024] A cellular communication environment is typically a controlled environment from a radio spectrum perspective, and frequency resources are managed so that interfering transmissions are sought to be placed at a safe distance from receivers so as to avoid, or reduce, effects of interference. However, in practice different wireless communication systems overlap in their coverage areas, and different wireless systems may even be implemented in a same communication device. For example a UE 110 may comprise, in addition to a cellular transceiver, also a Bluetooth, wireless local area network, WLAN and / or a near-field communication, NFC, transceiver.

[0025] Examples of situations where interference is possible due to limited radiofrequency, RF, isolation between transmitter and receiver include sub-band non-overlapping full duplex, SBFD, sidelink communication, in-device coexistence of multiple RATs, interdevice coexistence of multiple RATs, full duplex same frequency operation, unsynchronized networks, other commercial and / or non-commercial networks operating on same or adjacent frequency ranges, non-ideal filters when operating at high frequencies, such as sixth generation, 6G, frequency range 3, FR3, at 7 to 14 GHz. Further, some multi-subscriber identity module, SIM, use cases may in practice result in limited RF isolation.

[0026] In practice an interfering signal originating from outside the receiver, or from the same wireless communication device, and affecting a receiver of the wireless communication device may be in an active receive band of the receiver, such as, for example, in an active bandwidth part, BWP, used by the receiver. Such an interfering signal may occur as an intermodulation product of signals inside and / or outside the active receive band, as a frequency component within the active receive band from an adjacent system, or as adjacent- channel leakage from a transmitter in a spectrum part which is near the active receive bandof the receiver. As a result of the interfering signal, the receiver may be driven into compression. By this it is meant, that the receiver’s transfer function becomes nonlinear and demodulation becomes more difficult since the modulation constellation in used warped from its correct shape. The receiver may have difficulty determining, what is the cause of its impaired performance. The impaired performance itself may be determined, for example, from simultaneous high received power and low signal quality.

[0027] The definition of the BWP may follow the 3GPP specifications or, more generally, it may be understood as the prevailing operational frequency band used by the user equipment for transmissions and / or receptions. In the 3GPP specifications, the BWP is understood as a sub-band of a carrier bandwidth, wherein the carrier bandwidth is segmented into multiple BWPs allocated to different user equipment entities. There may be several concurrent BWPs that may even overlap in the frequency domain.

[0028] In 5G it is possible to adapt the transmit or receive operations to interference based on the UE channel state information, CSI, reports sent by the UE 110 to the network. However, if the receiver is operating in a non-linear region, measurements on interfering signals may be unreliable. The configuration of the transmissions and / or receptions by 5G UEs may be controlled by the network, for example based on the CSI reports sent by the UEs. The controlling may comprise provision of downlink control information, DCI, to the UE. The CSI reports may contain, among others, a channel quality information, CQI, and a rank indicator, RI. The reported CQI index corresponds to the highest modulation and coding scheme that can be achieved for a target transport block error rate of 10% or 0.001%. The RI is used by the UE to report a number of independent communication channels in a MIMO configuration.

[0029] The UE may be configured to report its capabilities in terms of maximum number of supported MIMO layers using higher layer parameters, such as maxNumberMIMO-LayersPDSCH, maxNumberMIMO-LayersCB-PUSCH, maxNumberMIMO-LayersNonCB-PUSCH for physical downlink shared channel, PDSCH, and physical uplink shared channel, PUSCH, respectively. In these parameters CB refers to codebook precoding and NonCB refers to non-codebook precoding. The network may be configured to define CSI reference signal, RS, resources to be measured and measurement reports to be transmitted, so that the network can continuously assess the prevailing channel conditions at the UE. Then the network may schedule DL receptions, or UL transmissions,by configuring suitable modulation and coding scheme, MCS, values and number of layers in the downlink control information, DCI.

[0030] The UEs may be configured to report back to the network whether they would prefer to temporarily reduce the number of MIMO layers in order to handle overheating at the UE, or for power saving purposes. When a MIMO layer is reduced, the number of independent data streams, delivered over independent spatial data paths, is reduced. For example, when two MIMO layers are in use, the transmitter may provide two separate data streams to the receiver, and reducing the MIMO layers to one would involve providing only a single data stream to the receiver. The reduction may also reduce the number of transmit antennas, and more generally transmit branches in use for transmission in the transmitter, releasing resources of the transmitting device, such as the UE, for other use(s). Similar reduction of resources applies to the UE operating as the receiver over the MIMO layers.

[0031] The resources released may include processing resources, since less MIMO processing needs to be done when fewer MIMO layers are in use. Likewise memory resources are released, as less memory is needed to convey a smaller number of data streams, including for channel coding purposes, compared to a larger number of data streams. Further, resources of the transmitter, such as an antenna or a transmit branch, may be released since, for example, a single data stream may be transmitted also from a single antenna or branch. More generally a smaller number of data streams may be transmitted or received using fewer transmit or reception branches of the transmitter, respectively. Accordingly, resources can be freed for another purpose such as measuring interference and reducing the adverse effects of the interference signal(s).

[0032] When a receiver, such as a receiver of a UE 110, is operating in its non-linear region, the spectrum at the input of its base band circuitry may be complex and, as the main receiver circuitry only detects signals inside the active receive band, also known as the channel bandwidth, any strong signals that cause undesired mixing products inside the active receive band are not directly detectable in a normal receive operation using the main receive circuitry.

[0033] In 5G, serving cell measurements are conducted within the active bandwidth part, BWP, of the UE, and consequently if the UE is close to operating in its non-linear region 5G measurements do not readily signal this condition to the network. In many scenarios, receiver loss of linearity does not occur frequently because 5G deployments andtheir frequency allocation are carefully planned to avoid situations where intermodulation products fall within the system’s operating band. The same applies to the reception, interference degrading reception of signals at the user equipment may not occur frequently, but the problem is still relevant. However, as discussed herein above, when different systems coexist in the same device, or in nearby devices, simultaneous transmission and reception may take place with little RF isolation. This causes a risk that a receiver is driven to nonlinear operation or that the reception quality degrades to a state of radio link failure. Recovering from a radio link failure involves signaling and incurs delays in communication.

[0034] In these cases, it would be beneficial to conduct measurements in the UE RF front end receive bandwidth, in a frequency sense more broadly than only within the active receive band, such as the active BWP in the case of 5G. Such measurements, referred to herein as wideband measurements, may find interfering signals present in the front end that are outside of the active receive band. Such interfering signals may cause intermodulation effects which occur on the active receive band, and thus impair receiver performance from outside the active receive band. UEs may have installed therein measurement circuitry configured to perform the wideband measurement in the RF front end.

[0035] The receiver may be configured to enable such wideband measurements, at least to an extent sufficient to discover strong spectral peaks within the RF front end receive bandwidth. The receiver may likewise be configured to perform interference reduction, such as nulling, suppressing or phasing out an interfering signal, on an interfering signal on the active receive band or in the front end receive bandwidth but outside the active receive band. The interference reduction may be conducted as spatial domain processing in the receiver, for example. The actual signal processing related to the interference reduction may be implemented according to the state-of-the-art interference reduction algorithms, and detailed description of that is beyoned the scope of the present disclosure. This document focuses on enabling sufficient resources for performing the interference measurements and the interference reduction at the receiver (UE). The interference reduction may, as noted above, use, at least in part, at least one resource of the receiving device which is released in connection with reducing the number of MIMO layers in use. The number of MIMO layers may, in particular, be reduced to one. Thus, the released resource(s) which is used in the interference reduction may, for example, be processing capability, memory, battery power, or a hardware resource of the transceiver which is no longer needed in MIMO transmission but which is usable in the interference reduction, such as nulling or phasing out. Example ofhardware resources usable in the interference reduction include combiners and phase shifters.

[0036] The network may configure in a UE at least one triggering condition relating to a reduction in multiple input multiple output, MIMO, layers in use on a bandwidth part the UE is using. This triggering condition(s) may be used by the UE to prompt the network to switch the UE to the mode of operation where MIMO layers are reduced to facilitate interference reduction, or this triggering condition(s) may be used by the UE to inform the network that the UE will autonomously switch to the mode of operation where MIMO layers are reduced to facilitate interference reduction. This triggering condition(s) may be generated in the network, such as in the base station, for example based on historical performance data of UEs in a coverage area of a cell controlled by the base station.

[0037] FIGURE 2A illustrates an example spectrum in accordance with at least some embodiments of the present invention. The drawing is not to scale. In the figure, frequency axis 201 is horizontal, with increasing frequency from the left toward the right. Active receive band 210 may correspond to an active BWP in case the 5G system is used, for example. The RF front end receive bandwidth 220 is broader than active receive band 210, and encompasses active receive band 210. Bandwidth 220 may be defined by a configurable or non-configurable hardware filter element in the transceiver, for example. The active receive band 210 is conveyed to the main receiver circuitry, the rest of bandwidth 220 being filtered away prior to this. Received signals 230 are modulated signals transmitted from the transmitter and intended for the receiver, carrying data for the receiver, such as the UE, for example. In an orthogonal frequency division multiplexing, OFDMA, transmission the number of frequency resources used to convey the data may be substantially more than the two illustrated in FIGURE 2A for the sake of clarity. In some communication technologies a single frequency component 230 is used, rather than the plural frequency components as in FIGURE 2A.

[0038] An interfering signal 240 is present in the RF front end receive bandwidth 220, outside active receive band 210. As such, it has passed through the receiver’s filters which remove spectrum components outside the RF front end receive bandwidth 220. As interfering signal 240 is fairly strong, it may generate an intermodulation product 250, falling in the active receive bandwidth and impairing receiver performance. If the interfering signal240 is reduced or even eliminated, intermodulation product 250 will vanish or at least be substantially reduced, and receiver performance will improve as a result.

[0039] FIGURE 2B illustrates an example signalling sequence in accordance with at least some embodiments of the present invention. On the vertical axes are disposed UE 110 on the left, and base station 130 on the right, for example as in FIGURE 1. Time advances from the top toward the bottom. Signalling illustrated in FIGURE 2B may be radio resource control, RRC, signalling, for example. Medium access control, MAC, control element, CE, based signaling may be used in some messages as an alternative to RRC signaling, for example in the signaling of phase 260 or 290.

[0040] In phase 260, UE 110 provides to base station 130 an indication that the UE is capable of using a resource released by reducing active MIMO layers in reducing interference. This may include that the UE is capable of performing the wideband RF frontend measurement discussed above. In phase 270, base station 130 provides to UE 110 a measurement configuration defining such a wideband measurement on the radio frequency front end receive frequency band 220, which is wider than the active bandwidth part 210 configured to the UE 110 by the base station 130. The configuration of phase 270 may further define how results of the measurement defined therein are to be reported back to the network, such as triggering conditions for reporting results back to the network.

[0041] Yet further, in phase 270 or in another phase, the base station may configure in UE 110 triggering conditions for the reduction in MIMO layers to release the resource(s) to use in interference reduction. A base station device serving UE 110 may be configured to generate and transmit to UE 110 at least one triggering condition defining conditions when the UE will report back to the network, that at least one triggering condition has been determined to be met in the UE, the at least one triggering condition relating to a reduction in multiple input multiple output, MIMO, layers in use on a bandwidth part the UE is using.

[0042] The measurement configuration may comprise a periodicity of these measurements and the frequencies to be measured in the wideband measurement. Further, the configuration may comprise at least one entry condition for performing the wideband measurements, for example, determined high RSRP and low RSRQ at the same time.

[0043] In phase 280, UE 110 conducts the wideband measurement defined in the configuration of phase 270, and phase 290 comprises the UE sending a report comprisingindications of results obtained from the wideband measurement of phase 280. Phase 290 may also comprise transmission of CQI from UE 110 to base station 130. The measurement of phase 280 may be a received signal strength indicator, RSSI, measurement, for example. The base station may subsequently configure the UE to enter the mode of operation of reduced MIMO layers and interference reduction, and consider the reduced number of MIMO layers in a subsequent DCI it sends to the UE.

[0044] The network may be configured to configure the UE to suppress the interference, using spatial signal processing, using the resource(s) released by reducing the number of MIMO layers, for example. The spatial signal processing may comprise determining, on the basis of the measurements, a direction from the interference signal is received at the UE and directing a transmission or reception null towards the determined direction. In case the interference reduction is used in connection with transmission, the transmission null may be generated towards the direction of the interference signal. In case the interference reduction is used in connection with reception, the reception null may be generated towards the direction of the interference signal.

[0045] The concept of wideband measurements may be understood such that the measurement bandwidth is wider than the active BWP. The measurement bandwidth may extend from one or both ends outside the active BWP. The measurement bandwidth may even extend outside a carrier bandwidth of a carrier which comprises the active BWP. The measurement bandwidth may be autonomously determined by the UE. Alternative to the wideband measurements, the actual measurement bandwidth may even be smaller than the bandwidth of the active BWP but may extend outside the active BWP. The embodiments described herein apply also to such measurements that employ a bandwidth not wider than the bandwidth of the active BWP.

[0046] FIGURE 3 illustrates an example apparatus capable of supporting at least some embodiments of the present invention. Illustrated is device 300, which may comprise, for example, a mobile communication device such as UE 110 or, in applicable parts, base station 130 of FIGURE 1. Comprised in device 300 is processor 310, which may comprise, for example, a single- or multi-core processor wherein a single-core processor comprises one processing core and a multi-core processor comprises more than one processing core. Processor 310 may comprise, in general, a control device. Processor 310 may comprise more than one processor. When processor 310 comprises more than one processor, device 300may be a distributed device wherein processing of tasks takes place in more than one physical unit. Processor 310 may be a control device. A processing core may comprise, for example, a Cortex-A8 processing core manufactured by ARM Holdings or a Zen processing core designed by Advanced Micro Devices Corporation. A processing core or processor may be, or may comprise, at least one qubit. Processor 310 may comprise at least one Qualcomm Snapdragon and / or Intel Atom processor. Processor 310 may comprise at least one application- specific integrated circuit, ASIC. Processor 310 may comprise at least one field- programmable gate array, FPGA. Processor 310, optionally together with memory and computer instructions, may be means for performing method steps in device 300. Processor 310 may be configured, at least in part by computer instructions, to perform actions.

[0047] A processor may comprise circuitry, or be constituted as circuitry or circuitries, the circuitry or circuitries being configured to perform phases of methods in accordance with embodiments described herein. As used in this application, the term “circuitry” may refer to one or more or all of the following: (a) hardware-only circuit implementations, such as implementations in only analogue and / or digital circuitry, and (b) combinations of hardware circuits and software, such as, as applicable: (i) a combination of analogue and / or digital hardware circuit(s) with software / firmware and (ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a user equipment or base station, to perform various functions) and (c) hardware circuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.

[0048] This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and / or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.

[0049] Device 300 may comprise memory 320. Memory 320 may comprise randomaccess memory and / or permanent memory. Memory 320 may comprise at least one RAMchip. Memory 320 may be a computer readable medium. Memory 320 may comprise solid- state, magnetic, optical and / or holographic memory, for example. Memory 320 may be at least in part accessible to processor 310. Memory 320 may be at least in part comprised in processor 310. Memory 320 may be means for storing information. Memory 320 may comprise computer instructions that processor 310 is configured to execute. When computer instructions configured to cause processor 310 to perform certain actions are stored in memory 320, and device 300 overall is configured to run under the direction of processor 310 using computer instructions from memory 320, processor 310 and / or its at least one processing core may be considered to be configured to perform said certain actions. Memory 320 may be at least in part external to device 300 but accessible to device 300. Memory 320 may be transitory or non-transitory. The term “non-transitory”, as used herein, is a limitation of the medium itself (that is, tangible, not a signal) as opposed to a limitation on data storage persistency (for example, RAM vs. ROM).

[0050] Device 300 may comprise a transmitter 330. Device 300 may comprise a receiver 340. Transmitter 330 and receiver 340 may be configured to transmit and receive, respectively, information in accordance with at least one cellular or non-cellular standard. Transmitter 330 may comprise more than one transmitter. Receiver 340 may comprise more than one receiver. Transmitter 330 and / or receiver 340 may be configured to operate in accordance with global system for mobile communication, GSM, wideband code division multiple access, WCDMA, 5G, long term evolution, LTE, IS-95, wireless local area network, WLAN, Ethernet and / or worldwide interoperability for microwave access, WiMAX, standards, for example.

[0051] Device 300 may comprise a near-field communication, NFC, transceiver 350. NFC transceiver 350 may support at least one NFC technology, such as NFC, Bluetooth, Wibree or similar technologies.

[0052] Device 300 may comprise user interface, UI, 360. UI 360 may comprise at least one of a display, a keyboard, a touchscreen, a vibrator arranged to signal to a user by causing device 300 to vibrate, a speaker or a microphone. A user may be able to operate device 300 via UI 360, for example to accept incoming telephone calls, to originate telephone calls or video calls, to browse the Internet, to manage digital files stored in memory 320 or on a cloud accessible via transmitter 330 and receiver 340, or via NFC transceiver 350, and / or to play games.

[0053] Device 300 may comprise or be arranged to accept a user identity module 370. User identity module 370 may comprise, for example, a subscriber identity module, SIM, card installable in device 300. A user identity module 370 may comprise information identifying a subscription of a user of device 300. A user identity module 370 may comprise cryptographic information usable to verify the identity of a user of device 300 and / or to facilitate encryption of communicated information and billing of the user of device 300 for communication effected via device 300.

[0054] Processor 310 may be furnished with a transmitter arranged to output information from processor 310, via electrical leads internal to device 300, to other devices comprised in device 300. Such a transmitter may comprise a serial bus transmitter arranged to, for example, output information via at least one electrical lead to memory 320 for storage therein. Alternatively to a serial bus, the transmitter may comprise a parallel bus transmitter. Likewise processor 310 may comprise a receiver arranged to receive information in processor 310, via electrical leads internal to device 300, from other devices comprised in device 300. Such a receiver may comprise a serial bus receiver arranged to, for example, receive information via at least one electrical lead from receiver 340 for processing in processor 310. Alternatively to a serial bus, the receiver may comprise a parallel bus receiver.

[0055] Device 300 may comprise further devices not illustrated in FIGURE 3. For example, where device 300 comprises a smartphone, it may comprise at least one digital camera. Some devices 300 may comprise a back-facing camera and a front-facing camera, wherein the back-facing camera may be intended for digital photography and the frontfacing camera for video telephony. Device 300 may comprise a fingerprint sensor arranged to authenticate, at least in part, a user of device 300. In some embodiments, device 300 lacks at least one device described above. For example, some devices 300 may lack a NFC transceiver 350 and / or user identity module 370.

[0056] Processor 310, memory 320, transmitter 330, receiver 340, NFC transceiver 350, UI 360 and / or user identity module 370 may be interconnected by electrical leads internal to device 300 in a multitude of different ways. For example, each of the aforementioned devices may be separately connected to a master bus internal to device 300, to allow for the devices to exchange information. However, as the skilled person will appreciate, this is only one example and depending on the embodiment various ways ofinterconnecting at least two of the aforementioned devices may be selected without departing from the scope of the present invention.

[0057] FIGURE 4 illustrates signalling in accordance with at least some embodiments of the present invention. On the vertical axes are disposed, on the left, device 110 of FIGURE 1 , and on the right, a personal computer PC 1. Time advances from the top toward the bottom.

[0058] Phases 410, 420, 430 and 440 correspond to phases 260, 270, 280 and 290 of FIGURE 2B, respectively. In phase 450 UE 110 determines that at least one triggering condition is met in the UE, the at least one triggering condition relating to a reduction in the multiple input multiple output, MIMO, layers in use on a bandwidth part the UE is using. For example, the triggering condition may be that received signal power is high, while signal quality is simultaneously low. Yet further, the triggering condition may include that an interfering signal was detected in the wideband measurement of phase 430. An example of a metric for the received signal power is reference signal received power, RSRP, and an example of a metric for the signal quality is reference signal received quality, RSRQ. For example, thresholds may be configured to determine high and low power and quality to define, at least in part, the triggering condition. The UE indicates the conditions(s) is / are fulfilled to the network in phase 460. In phase 460 the UE may also indicate, which MIMO branch it would prefer to use going forward, if the number of MIMO layers will be reduced, for example the UE may select the stronger branch for continued operation.

[0059] In optional phase 470 base station 130 indicates to UE 110 that it may switch to using the lower MIMO layer number and initiate interference reduction using the resource(s) released in the switch to the lower MIMO layer number. In case phase 470 is absent, UE 110 may proceed to the lower MIMO layer number and interference reduction without waiting for permission from the network.

[0060] In phase 480 UE 110 operates with the reduced number of active MIMO layers, using the resource(s) thereby released to perform interference reduction on the interfering signal, such as one discovered in the measurement of phase 430, for example. It is also possible, that a hardware resource released from the MIMO layer reduction is used to measure for interfering signals in the RF front end receive bandwidth and their characteristics during phase 480, and the information thus obtained is used in the interference reduction. The characteristics of the interfering signal may include their frequency and / or phase, for example.

[0061] In phase 490, base station 130 provides to UE 110 a scheduling DCI, which takes into account the reduced number of MIMO layers. Subsequently, in phase 4100, the UE determines that the triggering condition(s) relating to the reduced MIMO layer number and simultaneous interference reduction using the released resource are no longer fulfilled. For example, it may be the case that the interfering signal has ceased to exist. Phase 4100 may comprise measuring RSRP and RSRQ, for example. In phase 4110 UE 110 indicates to base station 130 that the triggering condition(s) are no longer fulfilled, and in phase 4120 the base station instructs the UE to switch back to normal behaviour and increase the number of MIMO layers back to the original value. As was the case for phase 470, also phase 4120 is optional, where it is absent UE 110 will switch back to the original MIMO arrangement without waiting for permission to do so from the network. Subsequently, the base station may schedule communications with UE 110 using the original MIMO arrangement.

[0062] The measurement configuration of phase 420 is also absent in some embodiments, such that in these embodiments the UE will employ a default measurement configuration.

[0063] The signalling of FIGURE 4 may be conducted as RRC signalling, for example. However as an alternative, MAC CE signalling may be used, which will reduce the delay from indication from UE to first DCI considering the UE in the new mode of operation. In particular, the messages of phases 460 and / or 4110 may be conveyed using MAC CEs, to facilitate prompt scheduling using the DCI.

[0064] FIGURE 5 is a flow graph of a method in accordance with at least some embodiments of the present invention. The phases of the illustrated method may be performed in UE 110, or in a control device configured to control the functioning thereof, when installed therein.

[0065] Phase 510 comprises providing to a network an indication that at least one triggering condition has been determined to be met in the apparatus, the at least one triggering condition relating to a reduction in multiple input multiple output, MIMO, layers in use on a bandwidth part the apparatus is using. Phase 520 comprises reducing a number of MIMO layers in use in the apparatus to thereby release at least one resource of the apparatus. Phase 530 comprises using the at least one released resource to perform interference reduction on an interfering signal received by the apparatus.

[0066] FIGURE 6 is a flow graph of a method in accordance with at least some embodiments of the present invention. The phases of the illustrated method may be performed in a base station, or in a control device configured to control the functioning thereof, when installed therein.

[0067] Phase 610 comprises receiving, in an apparatus, from a user equipment an indication that at least one triggering condition has been determined to be met in the user equipment, the at least one triggering condition relating to a reduction in multiple input multiple output, MIMO, layers in use on a bandwidth part the user equipment is using. Finally, phase 620 comprises reducing a number of MIMO layers in use in the apparatus in communication with the user equipment to thereby release at least one resource of the UE for interference reduction.

[0068] It is to be understood that the embodiments of the invention disclosed are not limited to the particular structures, process steps, or materials disclosed herein, but are extended to equivalents thereof as would be recognized by those ordinarily skilled in the relevant arts. It should also be understood that terminology employed herein is used for the purpose of describing particular embodiments only and is not intended to be limiting.

[0069] Reference throughout this specification to one embodiment or an embodiment means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Where reference is made to a numerical value using a term such as, for example, about or substantially, the exact numerical value is also disclosed.

[0070] As used herein, a plurality of items, structural elements, compositional elements, and / or materials may be presented in a common list for convenience. However, these lists should be construed as though each member of the list is individually identified as a separate and unique member. Thus, no individual member of such list should be construed as a de facto equivalent of any other member of the same list solely based on their presentation in a common group without indications to the contrary. In addition, various embodiments and example of the present invention may be referred to herein along with alternatives for the various components thereof. It is understood that such embodiments, examples, and alternatives are not to be construed as de facto equivalents of one another, but are to be considered as separate and autonomous representations of the present invention.

[0071] Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the preceding description, numerous specific details are provided, such as examples of lengths, widths, shapes, etc., to provide a thorough understanding of embodiments of the invention. One skilled in the relevant art will recognize, however, that the invention can be practiced without one or more of the specific details, or with other methods, components, materials, etc. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the invention.

[0072] While the forgoing examples are illustrative of the principles of the present invention in one or more particular applications, it will be apparent to those of ordinary skill in the art that numerous modifications in form, usage and details of implementation can be made without the exercise of inventive faculty, and without departing from the principles and concepts of the invention. Accordingly, it is not intended that the invention be limited, except as by the claims set forth below.

[0073] The verbs “to comprise” and “to include” are used in this document as open limitations that neither exclude nor require the existence of also un-recited features. The features recited in depending claims are mutually freely combinable unless otherwise explicitly stated. Furthermore, it is to be understood that the use of "a" or "an", that is, a singular form, throughout this document does not exclude a plurality.

[0074] As used herein, “at least one of the following: ” and “at least one of ” and similar wording, where the list of two or more elements are joined by “and” or “or”, mean at least any one of the elements, or at least any two or more of the elements, or at least all the elements.INDUSTRIAL APPLICABILITY

[0075] At least some embodiments of the present invention find industrial application in wireless communication.ACRONYMS LIST5G fifth generation6G sixth generationAMF access and mobility management functionBWP bandwidth partCQI channel quality indicationDCI downlink control informationOFDM orthogonal frequency division multiplexing RF radio frequencyRSRP reference signal received powerRSRQ reference signal received qualityUE user equipmentREFERENCE SIGNS LIST

Claims

CLAIMS:

1. An apparatus comprising at least one processing core and at least one memory storing instructions that, when executed by the at least one processing core, cause the apparatus at least to:- provide to a network an indication that at least one triggering condition has been determined to be met in the apparatus, the at least one triggering condition relating to a reduction in multiple input multiple output, MIMO, layers in use on a bandwidth part the apparatus is using;- reduce a number of MIMO layers in use in the apparatus to thereby release at least one resource of the apparatus, and- use the at least one released resource to perform interference reduction on an interfering signal received by the apparatus.

2. The apparatus according to claim 1, wherein the apparatus is configured to use the at least one released resource to perform the interference reduction on the interfering signal that is located in a frequency domain at least partly outside of the bandwidth part.

3. The apparatus according to claim 1 or 2, configured to perform the determination that the at least one triggering condition has been met based at least in part on a measurement, conducted by the apparatus, on a radio frequency front end receive frequency band which extends outside the bandwidth part in the frequency domain.

4. The apparatus according to claim 3, wherein the apparatus is configured to perform the interference reduction on the interfering signal based on information concerning the interfering signal obtained from the measurement.

5. The apparatus according to any of claims 3 or 4, further configured to process a configuration from the network, the configuration defining the measurement.

6. The apparatus according to claim 5, wherein the configuration further defines how the apparatus is to report results of the measurement to the network.

7. The apparatus according to any of claims 1 - 6, wherein the apparatus is configured to inform the network that the apparatus is capable of using a resource released by reducing active MIMO layers in reducing interference.

8. The apparatus according to any of claims 1 - 7, wherein the apparatus is configured to perform the reducing of the number of MIMO layers and reducing the interfering signal responsive to an instruction from the network.

9. The apparatus according to any of claims 1 - 8, wherein the apparatus is configured to provide to the network an indication that at least one triggering condition is no longer met.

10. The apparatus according to claim 9, wherein the apparatus is configured to process an instruction from the network to cease using the at least one released resource to at least partly phase out the interfering signal.

11. The apparatus according to any of claims 1 - 10, wherein the apparatus is configured to receive the at least one triggering condition from the network.

12. The apparatus according to any of claims 1 - 11, configured to perform the interference reduction at least in part by performing spatial domain processing.

13. An apparatus comprising at least one processing core and at least one memory storing instructions that, when executed by the at least one processing core, cause the apparatus at least to:- receive from a user equipment an indication that at least one triggering condition has been determined to be met in the user equipment, the at least one triggering condition relating to a reduction in multiple input multiple output, MIMO, layers in use on a bandwidth part the user equipment is using, the reduction being to release a resource for interference reduction, and- reduce a number of MIMO layers in use in the apparatus in communication with the user equipment to thereby release at least one resource of the user equipment for interference reduction.

14. The apparatus according to claim 13, further configured to provide to the user equipment an instruction to reduce the number of MIMO layers and to begin performing interference reduction on an interfering signal using the at least one released resource.

15. The apparatus according to claim 13 or 14, further configured to receive, from the user equipment, an indication that the user equipment is capable of using a resource released by reducing active MIMO layers in reducing interference.

16. The apparatus according to any one of claims 13 - 15, configured to generate and transmit the at least one triggering condition to the user equipment17. A method comprising:- providing, from an apparatus, to a network an indication that at least one triggering condition has been determined to be met in the apparatus, the at least one triggering condition relating to a reduction in multiple input multiple output, MIMO, layers in use on a bandwidth part the apparatus is using;- reducing a number of MIMO layers in use in the apparatus to thereby release at least one resource of the apparatus, and- using the at least one released resource to perform interference reduction on an interfering signal received by the apparatus.

18. The method according to claim 17, comprising using the at least one released hardware resource to perform the interference reduction on the interfering signal that is located in a frequency domain at least partly outside of the bandwidth part.

19. The method according to claim 17 or 18, comprising performing the determination that the at least one triggering condition has been met based at least in part on a measurement, conducted by the apparatus, on a radio frequency front end receive frequency band which extends outside the bandwidth part in frequency domain.

20. The method according to claim 19, wherein the method comprises performing the interference reduction on the interfering signal based on information concerning the interfering signal obtained from the measurement.

21. The method according to any of claims 19 or 20, further comprising processing a configuration from the network, the configuration defining the measurement.

22. The method according to claim 21, wherein the configuration further defines how the apparatus is to report results of the measurement to the network.

23. The method according to any of claims 17 - 21, wherein method comprises informing the network that the apparatus is capable of using a hardware resource released by reducing active MIMO layers in reducing interference.

24. The method according to any of claims 17 - 23, comprising performing the reducing of the number of MIMO layers and reducing the interfering signal as a response to an instruction from the network.

25. The method according to any of claims 17 - 24, wherein the method comprises providing to the network an indication that at least one triggering condition is no longer met.

26. The method according to claim 25, wherein the method comprises processing an instruction from the network to cease using the at least one released resource to at least partly phase out the interfering signal.

27. The method according to any of claims 17 - 26, wherein the method comprises receiving the at least one triggering condition from the network.

28. The method according to any of claims 17 - 27, comprising performing the interference reduction at least in part by performing spatial domain processing.

29. A method comprising:- receiving, in an apparatus, from a user equipment an indication that at least one triggering condition has been determined to be met in the user equipment, the at least one triggering condition relating to a reduction in multiple input multiple output, MIMO, layers in use on a bandwidth part the user equipment is using, andreducing a number of MIMO layers in use in the apparatus in communication with the user equipment to thereby release at least one resource of the user equipment for interference reduction.

30. The method according to claim 29 further comprising providing to the user equipment an instruction to reduce the number of MIMO layers and to begin performing interference reduction on an interfering signal using the at least one released resource.

31. The method according to claim 29 or 30, further comprising receiving, from the user equipment, an indication that the user equipment is capable of using a resource released by reducing active MIMO layers in reducing interference.

32. The method according to any one of claims 29 - 31, comprising generating and transmitting the at least one triggering condition to the user equipment.

33. An apparatus comprising means for:- providing to a network an indication that at least one triggering condition has been determined to be met in the apparatus, the at least one triggering condition relating to a reduction in multiple input multiple output, MIMO, layers in use on a bandwidth part the apparatus is using;- reducing a number of MIMO layers in use in the apparatus to thereby release at least one resource of the apparatus, and- using the at least one released resource to perform interference reduction on an interfering signal received by the apparatus.

34. An apparatus comprising means for:- receiving from a user equipment an indication that at least one triggering condition has been determined to be met in the user equipment, the at least one triggering condition relating to a reduction in multiple input multiple output, MIMO, layers in use on a bandwidth part the user equipment is using, the reduction being to release a resource for interference reduction, andreducing a number of MIMO layers in use in the apparatus in communication with the user equipment to thereby release at least one resource of the user equipment for interference reduction.

35. A non-transitory computer readable medium having stored thereon a set of computer readable instructions that, when executed by at least one processor, cause an apparatus to at least:- provide to a network an indication that at least one triggering condition has been determined to be met in the apparatus, the at least one triggering condition relating to a reduction in multiple input multiple output, MIMO, layers in use on a bandwidth part the apparatus is using;- reduce a number of MIMO layers in use in the apparatus to thereby release at least one resource of the apparatus, and- use the at least one released resource to perform interference reduction on an interfering signal received by the apparatus.

36. A non-transitory computer readable medium having stored thereon a set of computer readable instructions that, when executed by at least one processor, cause an apparatus to at least:- receive from a user equipment an indication that at least one triggering condition has been determined to be met in the user equipment, the at least one triggering condition relating to a reduction in multiple input multiple output, MIMO, layers in use on a bandwidth part the user equipment is using, the reduction being to release a resource for interference reduction, and- reduce a number of MIMO layers in use in the apparatus in communication with the user equipment to thereby release at least one resource of the user equipment for interference reduction.

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