Reference signal reporting configuration

Abstract

According to an example aspect of the present invention, there is provided a method comprising receiving by a wireless network node, from a user equipment, capability information indicating whether the user equipment has a capability to perform joint demodulation or separate demodulation of transmission layers received by the user equipment from a first transmission and reception point and a second transmission and reception point, determining by the wireless network node, based on the capability information, a reference signal reporting configuration for the user equipment, for reporting channel state information associated with reference signals transmitted by the first and second transmission and reception points, and transmitting, by the wireless network node, the reference signal reporting configuration to the user equipment.

Description

REFERENCE SIGNAL REPORTING CONFIGURATIONFIELD

[0001] Various example embodiments relate in general to cellular communication networks and more specifically, to reference signal reporting configuration in such networks.BACKGROUND

[0002] Reference signals are very important in various cellular communication networks, such as in cellular communication networks operating according to 5G radio access technology, to enable optimal performance. 5G radio access technology may also be referred to as new radio, NR, access technology. 3rd generation partnership project, 3 GPP, develops standards for 5G / NR and some topics in the 3 GPP discussions are related to reference signals. There is a need to provide improved methods, apparatuses and computer programs related to reference signal reporting configurations. Such improvements may be exploited in other cellular communication networks as well, like in 6G networks.SUMMARY

[0003] According to some aspects, there is provided the subject-matter of the independent claims. Some example embodiments are defined in the dependent claims.

[0004] The scope of protection sought for various example embodiments of the invention is set out by the independent claims. The example embodiments 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 example embodiments of the invention.

[0005] According to a first aspect of the present invention, there is provided an apparatus comprising at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to receive, from a user equipment, capability information indicating whether the user equipment has a capability to perform joint demodulation or separate demodulation of transmission layers received by the user equipment from a first transmission and reception point and a second transmission and reception point, determine, based on the capability information, a reference signal reporting configuration for the user equipment, for reporting channel state information associated with reference signals transmitted by the first and second transmission andreception points, and transmit the reference signal reporting configuration to the user equipment. The apparatus may be a wireless network node, such as a base station.

[0006] Example embodiments of the first aspect may comprise at least one feature from the following bulleted list or any combination of the following features:• wherein the reference signal reporting configuration is a group based beam reporting configuration;• wherein the stored instructions further cause, when executed by the at least one processor, the apparatus at least to determine that the reference signal reporting configuration comprises a reference signal received power reporting configuration when the capability information indicates that the user equipment has a capability to perform joint demodulation;• wherein the stored instructions further cause, when executed by the at least one processor, the apparatus at least to determine that the reference signal reporting configuration comprises a signal-to-interference and noise ratio reporting configuration when the capability information indicates that the user equipment has a capability to perform separate demodulation;• wherein the stored instructions further cause, when executed by the at least one processor, the apparatus at least to determine, based on the capability information, a reference signal configuration for the user equipment, for transmitting the reference signals from the first and second transmission and reception points and transmit reference signals from the first and second transmission and reception points to the user equipment in accordance with the reference signal configuration;• wherein reference signal resources from the first and second transmission and reception points are configured independently from each other when the capability information indicates that the user equipment has a capability to perform joint demodulation;• wherein a pair of reference signal resources from the first and second transmission and reception points are configured when the capability information indicates that the user equipment has a capability to perform separate demodulation, and wherein one reference signal resource of the pair of reference signal resources is configured for interference measurement;• wherein the stored instructions further cause, when executed by the at least one processor, the apparatus at least to cycle through multiple pairs of reference signal resources configured for the first and second transmission and reception points and transmit the multiple pairs of reference signal resources in a time sequential manner;• wherein the reference signals are channel state information reference signals, and the reference signal resources are 2-ports channel state information reference signal resources;• wherein the stored instructions further cause, when executed by the at least one processor, the apparatus at least to transmit, to the user equipment, a received power threshold value for reporting candidate beams and receive, from the user equipment, an indication of candidate beams that can be received simultaneously by the user equipment, wherein said candidate beams are beams received by the user equipment with a power higher than the threshold.

[0007] According to a second aspect of the present invention, there is provided an apparatus comprising at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to transmit, to a wireless network node, capability information indicating whether the apparatus has a capability to perform joint demodulation or separate demodulation of transmission layers received by the apparatus from a first transmission and reception point and a second transmission and reception point, and receive, from the wireless network node, a reference signal reporting configuration for the apparatus, for reporting channel state information associated with reference signals received by the user equipment from the first and second transmission and reception points, wherein the reference signal reporting configuration is based on the capability information. The apparatus may be a user equipment.

[0008] Example embodiments of the second aspect may comprise at least one feature from the following bulleted list or any combination of the following features:• wherein the reference signal reporting configuration is a group based beam reporting configuration;• wherein the reference signal reporting configuration comprises a reference signal received power reporting configuration when the capability information indicates that the apparatus has a capability to perform joint demodulation;• wherein the reference signal reporting configuration comprises a signal-to- interference and noise ratio reporting configuration when the capability information indicates that the apparatus has a capability to perform separate demodulation.

[0009] According to a third aspect of the present invention, there is provided a first method, comprising receiving by a wireless network node, from a user equipment, capability information indicating whether the user equipment has a capability to perform joint demodulation or separate demodulation of transmission layers received by the user equipment from a first transmission and reception point and a second transmission and reception point, determining by the wireless network node, based on the capability information, a reference signal reporting configuration for the user equipment, for reporting channel state information associated with reference signals transmitted by the first and second transmission and reception points, and transmitting, by the wireless network node, the reference signal reporting configuration to the user equipment. The wireless network node may be a base station.

[0010] According to a fourth aspect of the present invention, there is provided a second method, comprising transmitting by a user equipment, to a wireless network node, capability information indicating whether the user equipment has a capability to perform joint demodulation or separate demodulation of transmission layers received by the user equipment from a first transmission and reception point and a second transmission and reception point, and receiving by the user equipment, from the wireless network node, a reference signal reporting configuration for the user equipment, for reporting channel state information associated with reference signals received by the user equipment from the first and second transmission and reception points, wherein the reference signal reporting configuration is based on the capability information.

[0011] According to a fifth aspect of the present invention, there is provided an apparatus, comprising means for receiving, from a user equipment, capability information indicating whether the user equipment has a capability to perform joint demodulation or separate demodulation of transmission layers received by the user equipment from a first transmission and reception point and a second transmission and reception point, means for determining, based on the capability information, a reference signal reporting configuration for the user equipment, for reporting channel state information associated with referencesignals transmitted by the first and second transmission and reception points, and means for transmitting the reference signal reporting configuration to the user equipment. The apparatus may be a wireless network node, such as a base station.

[0012] According to a sixth aspect of the present invention, there is provided an apparatus, comprising means for transmitting, to a wireless network node, capability information indicating whether the apparatus has a capability to perform joint demodulation or separate demodulation of transmission layers received by the apparatus from a first transmission and reception point and a second transmission and reception point, and means for receiving, from the wireless network node, a reference signal reporting configuration for the apparatus, for reporting channel state information associated with reference signals received by the user equipment from the first and second transmission and reception points, wherein the reference signal reporting configuration is based on the capability information. The apparatus may be a user equipment.

[0013] According to a seventh aspect of the present invention, 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 perform the first method. According to an eighth aspect of the present invention, 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 perform the second method.

[0014] According to a ninth aspect of the present invention, there is provided a computer program comprising instructions which, when the program is executed by an apparatus, cause the apparatus to carry out the first method. According to a tenth aspect of the present invention, there is provided a computer program comprising instructions which, when the program is executed by an apparatus, cause the apparatus to carry out the second method.BRIEF DESCRIPTION OF THE DRAWINGS

[0015] FIG. 1 illustrates an example of a network scenario in accordance with at least some example embodiments;

[0016] FIG. 2a illustrates a UE using joint demodulation for 4-layers downlink MIMO in accordance with at least some example embodiments;

[0017] FIG. 2b illustrates a UE using separate demodulation for 4-layers downlink MIMO in accordance with at least some example embodiments;

[0018] FIG. 3 a illustrates UE demodulation of the desired and undesired signal in accordance with at least some example embodiments;

[0019] FIG. 3b illustrates a channel matrix in accordance with at least some example embodiments;

[0020] FIG. 4 illustrates a first signalling graph in accordance with at least some example embodiments;

[0021] FIG. 5 illustrates a second signalling graph in accordance with at least some example embodiments;

[0022] FIG. 6 illustrates an example apparatus capable of supporting at least some example embodiments;

[0023] FIG. 7 illustrates a flow graph of a method in accordance with at least some example embodiments;

[0024] FIG. 8 is a flow graph of a second method in accordance with at least some example embodiments.EXAMPLE EMBODIMENTS

[0025] Embodiments of the present disclosure provide improvements for reference signal for reference signal reporting configuration, which are suitable at least for cellular communication networks. A User Equipment, UE, may transmit capability information to a Base Station, BS, said capability information indicating whether the UE has a capability to perform joint demodulation or separate demodulation. The BS may then take said capability of the UE into account when determining a reference signal reporting configuration for the UE, for reporting Channel State Information, CSI, associated with Reference Signals, RSs, received by the UE from a first Transmission and Reception Point, TRP, and a second TRP. Hence, the BS may optimize reporting of the UE and scheduling of downlink RSs, to receiveaccurate reports quickly from the UE. Consequently, the BS can find the best beam pair for the UE.

[0026] FIG. 1 illustrates an example of a network scenario in accordance with at least some example embodiments. According to the example scenario of FIG. 1, there may be a network scenario, comprising UE 110, TRPs 120 and 122, BS 130 and core network 140. UE 110 may be connected to TRPs 120 via air interface 115. UE 110 may comprise, for example, a smartphone, a cellular phone, a Machine-to-Machine, M2M, node, Machine- Type Communications, MTC, node, an Internet of Things, loT, node, a Reduced Capability, RedCap, node, a car telemetry unit, a laptop computer, a tablet computer, a terrestrial / maritime / aerial vehicle, or, indeed, any kind of suitable wireless terminal.

[0027] BS 130 may be a network entity that configures some or all control information and allocates at least some resources for UE 110. BS 130 may control multiple TRPs 120, 122 that may be co-located or non-co-located. FIG. 1 illustrates a scenario, wherein TRPs 120, 122 are non-co-located, i.e., in different physical devices. In case of co-located TRPs, TRPs 120 and 122 may be in the same physical device and may share some common functions / circuitries. That is, in case of co-located TRPs, two antenna panels may be provisioned to generate co-located TRPs 120 and 122.

[0028] Air interface 115 between UE 110 and TRPs 120, 122 may be configured in accordance with a RAT, which UE 110 and TRPs 120, 122 are configured to support. Examples of cellular RATs include Long Term Evolution, LTE, New Radio, NR, which may also be known as fifth generation, 5G, radio access technology, 6G, and MulteFire. A cellular RAT may be standardized by a 3rdGeneration Partnership Project, 3GPP, for example. In the context of NR, BS 130 may be referred to as a gNB while in the context of LTE BS 130 may be referred to as an eNB. In any case, example embodiments of the present disclosure are not restricted to any particular wireless technology. Instead, example embodiments may be exploited in any wireless communication system, wherein signals are transmitted via two TRPs.

[0029] TRPs may be connected, directly or via at least one intermediate node, with BS 130 via wired interface 135 while BS 130 may be further connected to core network 140 via wired interface 145. Core network 140 may be, in turn, coupled via interface 145 with another network (not shown in FIG. 1), via which connectivity to further networks may be obtained, for example a worldwide interconnection network.

[0030] Multiple receiver chains may be exploited at least in cellular communication networks. For example, multiple receiver chains may be used in 3 GPP Rel-18 and Rel-19, such as 4-layers downlink Multiple-Input Multiple-Output, MIMO, in Frequency Range 2, FR2. In such a case, UE 110 may be equipped with multiple antenna panels, e.g., 2 panels, and with multiple receiver chains, e.g., 2 dual polarized receiver chains. At least in case of FR2, UE 110 may form refined beams with antenna arraying techniques for increasing the gain and link budget. Then, UE 110 may steer the beams for optimum alignment with the transmitter, e.g., with antenna arrays and analog phase shifters. The refined and steered beams may have significant side lobes picking undesired signals though.

[0031] FIG. 2a illustrates a UE using joint demodulation for 4-layers downlink MIMO in accordance with at least some example embodiments. FIG. 2b illustrates a UE using separate demodulation for 4-layers downlink MIMO in accordance with at least some example embodiments.

[0032] 4-layers downlink MIMO may be considered for example in intra-cell multi- TRP framework with a Downlink Control Information, DCI, scheme, such as a sDCI scheme where each TRP 120, 122 may transmit 2-ports CSI-RS beams. TRPs 120, 122 may belong to the cell Physical Cell Identifier, PCI, and UE 110 may receive a first 2-ports CSI-RS resource CSI#1 on a first antenna array and a second 2-ports CSI-RS resource CSI#2 on a second antenna array, as illustrated in FIG. 2a. In such a scenario, strong antenna side lobes of UE 110 may cause polluting the desired receive signal by undesired signals, possibly measured with relatively high receiver antenna gain. The ratio between desired and undesired gain may be significantly affected by the choice of TRP beam pair. For example, the beam pair CSI#1 (transmitted by first TRP 120) and CSI#2 (transmitted by second TRP 122) may only have 5 dB gain difference at the receiver beam of UE 110, while the beam pair CSI#1 (transmitted by first TRP 120) and CSI#3 (a third 2-ports CSI-RS resource transmitted by second TRP 122) may have 15 dB gain difference at the same receiver beam of UE 110, as illustrated in FIG. 2b. The undesired signal may lead to interference depending on how UE 110 performs the demodulation of the received signal.

[0033] Demodulation procedure of UE 110 may be joint or separate in, e.g., in 4-layers DL MIMO. In some example embodiments, the choice of the demodulation procedure may be fixed in the system on chip hardware architecture. The procedure at UE 110 may differ depending on whether a joint or a separate demodulation procedure for the 4 layers is used.

[0034] FIG. 3 a illustrates UE demodulation of the desired and undesired signal in accordance with at least some example embodiments. FIG. 3b illustrates a channel matrix in accordance with at least some example embodiments.

[0035] In the joint demodulation case, UE 110 may jointly and simultaneously demodulate all 4 layers with 4 receiver chains, 4 Analog-to-Digital Converters, ADCs, and 4 parallel Fast Fourier Transform, FFT, modules in the baseband unit. The entire 4x4 channel matrix (as depicted in FIG. 3b) may be inverted. There is hence no interference due to the detection by UE 110 and the beam pairs that will achieve highest throughput are the beams with highest Received Signal Reference Power, RSRP.

[0036] In the separate demodulation case, UE 110 may separately and autonomously demodulate two times 2 layers. UE 110 may only invert the two 2x2 diagonal blocks of the overall 4x4 channel matrix while leaving the other two 2x2 off-diagonal blocks of the overall 4x4 channel matrix as interference, which would lead to throughput degradation and possible sub-optimal performance. As some elements may create interference and degrade achievable throughput of the beam pair, the best throughput will come from optimizing Signal-to- Interference and Noise Ratio, SINR, rather than finding the best RSRP. The beam pairs that will optimize SINR may not be the same than the ones that maximize RSRP.

[0037] So at least one challenge is that there may be interference in separate demodulation which may be transparent (cancelled out) in joint demodulation, but the demodulation procedure used at UE 110 is unknown from the network. Group Based Beam Reporting, GBBR, may be provided for the beams of the group. Ll-RSRP may only provide power feedback from diagonal elements of the matrix, but no interference values. Furthermore, Ll-SINR may provide interference values but from any interferer so Ll-SINR might not isolate the interference from the unwanted CSI signal of the beam pair alone.

[0038] If the network is unaware of the type of demodulation used by UE 110 (joint or separate), the network cannot not know how to configure RS reporting depending on whether UE 110 has a capability to perform joint demodulation or separate modulation. For example, the network cannot know when to configure GBBR for Ll-RSRP or GBBR for Ll-SINR at UE 110. Therefore, the chosen CSI beams for simultaneous scheduling cannot be adapted by BS 130 for optimal beam pair choice (to limit interference from undesired signals) and no throughput optimization can be performed. Sub-optimal performance would be hence achieved without improvements.

[0039] Furthermore, if the separate demodulation procedure would be used at UE 110, the beam pair search itself would be sub-optimal, at least if the number of beam pairs to measure would be very high. How to conduct the beam pair search (the network scheduling simultaneous pairs of downlink RS and UE measurements and reporting) may be further optimized to speed up the search if the network is aware of the type of demodulation procedure followed by UE 110.

[0040] To give an example, if UE 110 uses joint demodulation, as illustrated in FIG. 2a, the contribution of CSI#2 (transmitted by second TRP 122) on a first antenna panel of UE 110 may be cancelled out in the signal decoding. As such, if CSI#1 (transmitted by first TRP 120) and CSI#2 (transmitted by second TRP 122) are the beams reported with the best RSRP, CSI#1 and CSI#2 would constitute the best beam pair, i.e., the highest achievable throughput. However, if UE 110 would use separate demodulation, as illustrated in FIG. 2b, the contribution of CSI#2 (transmitted by second TRP 122) onto the first antenna panel of UE 110 would be creating substantial interference. Therefore, the choice of beam pair needs to optimize received power and cross-beam interference. In this case, CSI#1 and CSI#2 would not be the best beam pair for UE 110 performing separate demodulation. Instead, CSI#1 and CSI#3 would the best beam pair for throughput. So, if BS 130 cannot distinguish the two above scenarios, BS 130 cannot optimize UE reporting of UE 110, such as whether UE 110 is to report RSRP or SINR, and the downlink RS scheduling (which simultaneous pairs if any) to get the fastest and most accurate report from UE 110, and to find the best beam pair.

[0041] At least some example embodiments of the present disclosure therefore make it possible for BS 130 to distinguish said scenarios and configure RS reporting of UE 110 accordingly. UE 110 may have a capability to indicate to BS 130 whether it has a capability to perform joint demodulation or separate demodulation of transmission layers received by UE 110 from first TRP 120 and second TRP 122 respectively. After that, BS 130 may determine a RS reporting configuration for UE 110, based on capability information of UE 110, and transmit the configuration to UE 110. The RS reporting configuration may be associated with RSs transmitted by first TRP 120 and second TRP 122.

[0042] For example, BS 130 may provide association of the GBBR configuration to UE 110 using Radio Resource Control, RRC, signalling depending on the reported demodulation capability by UE 110. In case of joint demodulation, BS 130 may determinethat the RS reporting configuration of UE 110 is Ll-RSRP GBBR configuration. In case of separate demodulation, BS 130 may determine that the RS reporting configuration of UE 110 is Ll-SINR GBBR configuration.

[0043] In some example embodiments, in case of separate demodulation, BS 120 may determine a beam to UE receiver chain association for UE 110, for crosstalk reporting per CSI resource. The RS reporting configuration may be for reporting CSI and a CSI measurement configuration may be specific to a beam pair including intended channel / reference signal and the interfering channel / reference signal. The configuration may comprise an explicit interferer: CSI-IM=NZP-CSI-RS. Alternatively, or in addition, BS 130 may add a CSI-IM resource for general interference that may be reported, comprising the known interferer and any other interference as well.

[0044] In some example embodiments, BS 130 may associate the scheduling by BS 130 of downlink RS to the reported demodulation capability of UE 110. In case of joint demodulation, BS 130 may schedule independent 2-ports CSI-RS resources (sequentially or simultaneously). In case of separate demodulation, BS 130 may schedule separate sequential pairs of 2-ports CSI-RS resources.

[0045] When UE 110 is configured to only report Ll-RSRP GBBR, but not Ll-SINR GBBR, BS 130 may schedule independent 2-ports CSI-RS resources from first TRP 120 and second TRP 122as downlink RS (sequentially or independently) and choose the 2 best beams only based on received power, but not interference. However, when UE 110 is configured to report Ll-SINR GBBR, BS 130 may sequentially schedule pairs of 2-ports CSI-RS resources from first TRP 120 and second TRP 122 until it finds the best combination. This exhaustive search is then only limited to UEs that have reported the separate demodulation capability.

[0046] In some example embodiments, the RRC configuration for ‘separate’ case may have two sets for intended signal and two sets for interference, wherein an interference resource may be mirrored from intended resources, and there may be one-to-one mapping between intended channel measurement set and interference measurement set.

[0047] FIG. 4 illustrates a first signalling graph in accordance with at least some example embodiments. FIG. 4 illustrates RS reporting based on UE 110 reporting joint demodulation capability. On the vertical axes are disposed, from the left to the right, BS 130 and UE 110 of FIG. 1. Time advances from the top towards the bottom.

[0048] At step 402, connection establishment may be performed. UE 110 may transmit information about its capabilities to BS 130, such as a capability information indicating whether UE 110 has a capability to perform joint demodulation (bit-1) or separate demodulation (bit-0) of transmission layers received by UE 110 from first TRP 120 and second TRP 122. At step 404, UE 110 may be moved to RRC connected state. The transmission layers and the RSs may be transmitted from two different antenna panels of the same TRP, wherein the same TRP would comprise first TRP 120 and second TRP 122, or from two different TRPs. In some example embodiments, a set of N transmission layers may be received from N different antenna panels of the same TRP and / or from N different TRPs (or any combination of antenna panels per TRPs and of TRPs).

[0049] At step 406, BS 130 may determine, based on the capability information, a RS reporting configuration for the user equipment, for reporting CSI associated with RSs transmitted by first TRP 120 and second TRP 122 respectively. If UE 110 supports joint demodulation (bit-1), Ll-RSRP provides optimum beam pair for 4-layers downlink MIMO. If UE 110 supports separate demodulation (bit-0), Ll-SINR provides optimum beam pair for 4-layers downlink MIMO.

[0050] In the example of FIG. 4, BS 130 may hence determine that the RS reporting configuration comprises a RSRP reporting configuration when the capability information indicates that UE 110 has a capability to perform joint demodulation. In some example embodiments, BS 130 may determine, based on the capability information, a RS configuration for UE 110, for transmitting and receiving the RSs from first TRP 120 and second TRP 122.

[0051] At step 408, BS 130 may transmit the RS reporting configuration to UE 110, wherein the configuration comprises a RSRP reporting configuration. For example, BS 130 may transmit an RRC configuration of GBBR with Ll-RSRP based reporting. At step 410, BS 130 may configure RSs from first TRP 120 and second TRP 122 independently from each other, when the capability information indicates UE 110 has a capability to perform joint demodulation. That is, downlink RSs may be independently scheduled from either TRP for downlink RSRP computation at UE 110.

[0052] At steps 412 - 418, BS 130 may transmit RSs from first TRP 120 and second TRP 122 to UE 110 in accordance with the RS configuration. At step 412, BS 130 may transmit 2-ports CSI-RS resource CSI-RS#1 (for H+V polarizations) from first TRP 120. Atstep 414, BS 130 may transmit 2-ports CSI-RS resource CSI-RS#2 (for H+V polarizations) from first TRP 120. At step 416, BS 130 may transmit 2-ports CSI-RS resource CSI-RS#3 (for H+V polarizations) from second TRP 122. At step 418, BS 130 may transmit 2-ports CSI-RS resource CSI-RS#4 (for H+V polarizations) from second TRP 122.

[0053] At step 420, UE 110 may have received each downlink RS and determine, based on the received RSs, the 2 best CRI (1 per TRP) according to best RSRP values. At step 422, UE 110 may report the 2 best CRI to BS 130. For example, UE 110 may report in GBBR the LI -RSRP values of the beams that can be received simultaneously. At step 424, BS 130 may perform best beam pair selection based on the report of UE 110 for best RSRP. At step 426, 4-layers Physical Downlink Shared Channel, PDSCH, scheduling may be performed by BS 130.

[0054] FIG. 5 illustrates a second signalling graph in accordance with at least some example embodiments. FIG. 5 illustrates RS reporting based on UE 110 reporting separate demodulation capability. On the vertical axes are disposed, from the left to the right, BS 130 and UE 110 of FIG. 1. Time advances from the top towards the bottom. Steps 402 - 406 may be performed before step 502, but in the example of FIG. 5, BS 130 may determine that the RS reporting configuration comprises a SINR reporting configuration when the capability information indicates that UE 110 has a capability to perform separate demodulation.

[0055] At step 502, BS 130 may transmit the RS reporting configuration to UE 110, wherein the configuration comprises a SINR reporting configuration. For example, BS 130 may transmit an RRC configuration of GBBR with Ll-SINR based reporting. At step 504, BS 130 may transmit to UE 110 a received power threshold value for reporting candidate beams. The threshold may be a threshold for good RSRP value of UE beam selection with SINR. At step 506, BS 130 may transmit periodic SS bursts for LI measurement. At step 508, UE 110 may classify highest RSRP beams and map RSRP values per beam to all antenna panels of UE 110. At step 510, UE 110 may select candidate pair of beams, such as Synchronization Signal Block, SSB, beams for both good RSRPs based on the threshold, and with low SINR. At step 512, UE 110 may transmit to BS 130 information about SSB beams that may be received simultaneously by UE 110, i.e., received on different antenna panels of UE 110 with good RSRP (above the threshold) and low SINR.

[0056] At step 514, BS 130 may configure a pair of RS resources from first TRP 120 and second TRP 122, to be possibly transmitted simultaneously, when the capability information indicates that UE 110 has a capability to perform separate demodulation. BS 130 may also configure one RS resource of the pair of RS resources for interference measurement. That is, a pair of downlink RS resources may be (simultaneously) scheduled from both TRPs for downlink SINR computation at UE 110. At step 516, BS 130 may select CSI beams among UE 110 reported candidate beams, such as SSB beams.

[0057] At step 518, BS 130 may transmit an RS configuration to UE 110, to configure the RSs for measuring the interference. For instance, BS 130 may transmit an RRC configuration of the CSI resources to measure the interference caused by each beam of a candidate pair of beams.

[0058] At steps 520 - 534, BS 130 may transmit RSs from first TRP 120 and second TRP 122 to UE 110 in accordance with the RS configuration. At step 520, BS 130 may transmit 2-ports CSI-RS resource CSI-RS#1 (for H+V polarizations) from first TRP 120 configured as an intended signal, and 2-ports CSI-RS resource CSI-RS#3 (for H+V polarizations) from second TRP 122 configured as an interferer. At step 522, BS 130 may transmit 2-ports CSI-RS resource CSI-RS#1 (for H+V polarizations) from first TRP 120 configured as an interferer, and 2-ports CSI-RS resource CSI-RS#3 (for H+V polarizations) from second TRP 122 configured as an intended signal. At step 524, BS 130 may transmit 2-ports CSI-RS resource CSI-RS#2 (for H+V polarizations) from first TRP 120 configured as an intended signal, and 2-ports CSI-RS resource CSI-RS#4 (for H+V polarizations) from second TRP 122 configured as an interferer. At step 526, BS 130 may transmit 2-ports CSI- RS resource CSI-RS#2 (for H+V polarizations) from first TRP 120 configured as an interferer, and 2-ports CSI-RS resource CSI-RS#4 (for H+V polarizations) from second TRP 122 configured as an intended signal.

[0059] At step 528, BS 130 may transmit 2-ports CSI-RS resource CSI-RS#1 (for H+V polarizations) from first TRP 120 configured as an intended signal, and 2-ports CSI- RS resource CSI-RS#4 (for H+V polarizations) from second TRP 122 configured as an interferer. At step 530, BS 130 may transmit 2-ports CSI-RS resource CSI-RS#1 (for H+V polarizations) from first TRP 120 configured as an interferer, and 2-ports CSI-RS resource CSI-RS#4 (for H+V polarizations) from second TRP 122 configured as an intended signal. At step 532, BS 130 may transmit 2-ports CSI-RS resource CSI-RS#2 (for H+Vpolarizations) from first TRP 120 configured as an intended signal, and 2-ports CSI-RS resource CSI-RS#3 (for H+V polarizations) from second TRP 122 configured as an interferer. At step 534, BS 130 may transmit 2-ports CSI-RS resources CSI-RS#2 (for H+V polarizations) from first TRP 120 configured as an interferer, and 2-ports CSI-RS resource CSI-RS#3 (for H+V polarizations) from second TRP 122 configured as an intended signal.

[0060] At step 536, UE 110 may have received each downlink RS and determine, based on the received RSs, the 2 best CRI (1 per TRP) according to best SINR values. At step 538, UE 110 may report the 2 best CRI to BS 130. For example, UE 110 may report in GBBR the Ll-SINR values of the beams that can be received simultaneously. At step 540, BS 130 may perform best beam pair selection based on the report of UE 110 for best SINR. At step 542, 4-layers Physical Downlink Shared Channel, PDSCH, scheduling may be performed by BS 130. In some example embodiments, the RRC configuration for separate modulation may comprise two sets for an intended signal and two sets for interference, wherein an interference resource may be mirrored from intended resources, and there may be one-to-one mapping between intended channel measurement set and interference measurement set.

[0061] In case of UE 110 reporting separate demodulation technique as a capability, BS 130 may have the cross-beam power level reporting to compute the best beam pair. For example, the Ll-SINR may provide the interference level from any interferer, and not just from the candidate CSI beam.

[0062] In some example embodiments, 3GPP standard specification TS 38.214 may be amended to cover at least some parts of the present disclosure. For example, different measurement configurations may be defined explicitly in TS 38.214 for separate demodulation schemes, wherein BS 130 provides interference resources for Ll-SINR computation, for example as follows:• For aperiodic CSI, and for aperiodic CSI resource settings, if groupBasedBeamReporting-rl7 is configured and UE-jointRXCapability = ‘Separate’, each trigger state configured using the higher layer parameter CSI-AperiodicTriggerState is associated with resourcesForChannel and resourcesForChannel2, which correspond to first and second resource sets and nzp-CSI-RS-ResourceForChannel and nzp-CSLRS- ResourceForChannel2, respectively, for Ll-SINR measurement;• For periodic and semi-persistent CSI resource settings, if groupBasedBeamReporting-rl7 and UE-jointRXCapability = ‘Separate’ - are configured and,• When two Resource Settings are configured, the first Resource Setting (given by higher layer parameter resourcesForChannelMeasurement) is for channel measurement on SSB or NZP-CSI-RS and the second Resource Setting (given by higher layer parameter csi-IM-ResourcesForlnterference) is used for interference measurement performed on CSI- IM or NZP-CSI-RS. In such a case, the number of configured CSI-Resource sets for channel measurements in the Resource Setting is 2. Moreover, the number of configured NZP-CSI- Resources for interference measurement in the Resource Setting is 2. For Ll-SINR computation, the first Resource Setting (given by higher layer parameter resourcesForChannelMeasurement) is used for channel measurement performed on NZP CSI-RS. The second Resource Setting (given by higher layer parameter csi-IM- ResourcesForlnterference or higher layer parameter nzp-CSI-RS-ResourceForlnterference) is used for interference measurement performed on CSI-IM or on NZP CSI-RS. For each Ll-SINR value, each SSB or NZP-CSI-RS resource for channel measurement is associated with one CSI-IM resource or one NZP-CSI-RS resource for interference measurement by the ordering of the SSB or NZP CSI-RS resource for channel measurement and CSI-IM resource or NZP CSI-RS resource for interference measurement in the corresponding resource sets. The number of SSB(s) or CSI-RS resources for channel measurement equals to the number of CSI-IM resources or the number of NZP CSI-RS resource for interference measurement.

[0063] The above modification may be valid for aperiodic, periodic and semi- persistent resources.

[0064] In some example embodiments, it may be valuable information for BS 130 to know how many panels are receiving a given CSI-RS, in order to reduce the number of measurement configurations and the number of downlink RSs that have to be scheduled from the network. For example, if a given CSI-RS is only detected on a single antenna panel of UE 110, then any pair of beams including this CSI beam will not suffer from interference due to this CSI beam. Therefore, the network does not need to schedule additional interference measurements. On the other hand, if a given CSI is measured on two antenna panels of UE 110 with similar power levels, then any beam pair including this CSI beamneeds to be checked for the interference level between the CSI beams as it could lead to throughput degradation.

[0065] In some example embodiments, UE 110 may report the power level received from any one given CSI beam from multiple UE receive panels. For this, a measurement configuration may be transmitted from the network to UE including a beam of BS 130 (i.e., Transmit Configuration Index, TCI, state) to an antenna panel of UE 110 (i.e., receiver chain ofUE 110 or Sounding Reference Signal, SRS, resource set) association, e.g. with Channel Measurement Resource, CMR, resources and groups.

[0066] Such a measurement configuration may be a part of the GBBR configuration, wherein the number of panels measuring a particular SSBRI / CRI resource may be explicitly indicated. Alternatively, the received power level per panel per beam may be explicitly indicated, or BS 130 may configure a threshold for the “adjacent” panels such that a SSBRVCRI resource may be considered by UE 110, or not. In some example embodiments, an antenna panel of UE 110 may be described as a receiver chain or as an SRS resource set.

[0067] In some example embodiments, with an indication of UE 110, the network may know the number of modules associated to each beam and configure how many RSs are needed to find the best beam pair from an Ll-SINR perspective.

[0068] Even though a scenario with 2 TRPs is used in various example embodiments, the operation may be extended to 3 or more (co-located or non co-located) TRPs similarly. For example, in case of N TRPs, 1 CSI-RS resource from a given TRP may be used for direct channel estimation, and N-l CSI-RS resources from the N-l remaining TRPs may be used for interference measurements.

[0069] In some example embodiments, BS 130 may receive, from UE 110, capability information indicating whether UE 110 has capability to perform joint demodulation or separate demodulation of N transmission layers received by UE 110 from N TRPs respectively. BS 130 may then determine, based on the capability information, a reference signal reporting configuration for UE 110, for reporting CSI associated with reference signals transmitted by the N TRPs and transmit the reference signal reporting configuration to UE 110.

[0070] In some example embodiments, BS 130 may determine, based on the capability information, a reference signal configuration for UE 110, for transmitting the referencesignals from the N TRPs and transmit reference signals from the N TRPs to UE 110 in accordance with the reference signal configuration.

[0071] In some example embodiments, N reference signal resources from the TV TRPs may be configured independently from each other when the capability information indicates that UE 110 has a capability to perform joint demodulation.

[0072] In some example embodiments, a set of N reference signal resources from the N TRPs may be configured (to be possibly transmitted simultaneously) when the capability information indicates that UE 110 has a capability to perform separate demodulation, and N- 1 reference signal resources of the set of N reference signal resources may be configured for interference measurement.

[0073] In some example embodiments, BS 130 may cycle through multiple sets of N reference signal resources configured for the TV TRPs respectively, and transmit the multiple sets of N reference signal resources in a time sequential manner.

[0074] FIG. 6 illustrates an example apparatus capable of supporting at least some example embodiments. Illustrated is device 600, which may comprise, for example, UE 110 or BS 130. Comprised in device 600 is processor 610, 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 610 may comprise, in general, a control device. Processor 610 may comprise more than one processor. Processor 610 may be a control device. Processor 610 may comprise at least one Application-Specific Integrated Circuit, ASIC. Processor 610 may comprise at least one Field-Programmable Gate Array, FPGA. Processor 610 may comprise at least one Qualcomm Snapdragon and / or Intel Atom processor. Processor 610 may comprise, for example, a Cortex-A8 processing core manufactured by ARM Holdings or a Steamroller processing core produced by Advanced Micro Devices Corporation. Processor 610 may be means for performing method steps in device 600, such as determining, causing transmitting and causing receiving. Processor 610 may be configured, at least in part by computer instructions, to perform actions.

[0075] 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 example embodiments described herein. As used in this application, the term “circuitry” mayrefer to one or more or all of the following: (a) hardware-only circuit implementations, such as implementations in only analog and / or digital circuitry, and (b) combinations of hardware circuits and software, such as, as applicable: (i) a combination of analog and / or digital hardware circuit(s) with software / firmware and (ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a network function, 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.

[0076] 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.

[0077] Device 600 may comprise memory 620. Memory 620 may comprise randomaccess memory and / or permanent memory. Memory 620 may comprise at least one RAM chip. Memory 620 may comprise solid-state, magnetic, optical and / or holographic memory, for example. Memory 620 may be at least in part accessible to processor 610. Memory 620 may be at least in part comprised in processor 610. Memory 620 may be means for storing information. Memory 620 may comprise computer instructions that processor 610 is configured to execute. When computer instructions configured to cause processor 610 to perform certain actions are stored in memory 620, and device 600 overall is configured to run under the direction of processor 610 using computer instructions from memory 620, processor 610 and / or its at least one processing core may be considered to be configured to perform said certain actions. Memory 620 may be at least in part comprised in processor 610. Memory 620 may be at least in part external to device 600 but accessible to device 600.

[0078] Device 600 may comprise a transmitter 630. Device 600 may comprise a receiver 440. Transmitter 630 and receiver 640 may be configured to transmit and receive, respectively, information in accordance with at least one cellular or non-cellular standard.Transmitter 630 may comprise more than one transmitter. Receiver 640 may comprise more than one receiver. Transmitter 630 and / or receiver 640 may be configured to operate in accordance with Global System for Mobile communication, GSM, Wideband Code Division Multiple Access, WCDMA, Long Term Evolution, LTE, and / or 5G / NR standards, for example.

[0079] Device 600 may comprise a Near-Field Communication, NFC, transceiver 650. NFC transceiver 650 may support at least one NFC technology, such as Bluetooth, Wibree or similar technologies.

[0080] Device 600 may comprise User Interface, UI, 660. UI 660 may comprise at least one of a display, a keyboard, a touchscreen, a vibrator arranged to signal to a user by causing device 600 to vibrate, a speaker and a microphone. A user may be able to operate device 600 via UI 660, 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 620 or on a cloud accessible via transmitter 630 and receiver 640, or via NFC transceiver 650, and / or to play games.

[0081] Device 600 may comprise or be arranged to accept a user identity module 670. User identity module 670 may comprise, for example, a Subscriber Identity Module, SIM, card installable in device 600. A user identity module 670 may comprise information identifying a subscription of a user of device 600. A user identity module 670 may comprise cryptographic information usable to verify the identity of a user of device 600 and / or to facilitate encryption of communicated information and billing of the user of device 600 for communication effected via device 600.

[0082] Processor 610 may be furnished with a transmitter arranged to output information from processor 610, via electrical leads internal to device 600, to other devices comprised in device 600. Such a transmitter may comprise a serial bus transmitter arranged to, for example, output information via at least one electrical lead to memory 620 for storage therein. Alternatively to a serial bus, the transmitter may comprise a parallel bus transmitter. Likewise processor 610 may comprise a receiver arranged to receive information in processor 610, via electrical leads internal to device 600, from other devices comprised in device 600. Such a receiver may comprise a serial bus receiver arranged to, for example, receive information via at least one electrical lead from receiver 640 for processing inprocessor 610. Alternatively to a serial bus, the receiver may comprise a parallel bus receiver.

[0083] Device 600 may comprise further devices not illustrated in FIG. 6. For example, where device 600 comprises a smartphone, it may comprise at least one digital camera. Some devices 600 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 600 may comprise a fingerprint sensor arranged to authenticate, at least in part, a user of device 600. In some embodiments, device 600 lacks at least one device described above. For example, some devices 600 may lack a NFC transceiver 650 and / or user identity module 670.

[0084] Processor 610, memory 620, transmitter 630, receiver 640, NFC transceiver 650, UI 660 and / or user identity module 670 may be interconnected by electrical leads internal to device 600 in a multitude of different ways. For example, each of the aforementioned devices may be separately connected to a master bus internal to device 600, 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 of interconnecting at least two of the aforementioned devices may be selected without departing from the scope of the embodiments.

[0085] FIG. 7 is a flow graph of a first method in accordance with at least some example embodiments. The phases of the illustrated first method may be performed by BS 130.

[0086] The first method may comprise, at step 710, receiving by a wireless network node, from a user equipment, capability information indicating whether the user equipment has a capability to perform joint demodulation or separate demodulation of transmission layers received by the user equipment from a first transmission and reception point and a second transmission and reception point. The first method may also comprise, at step 720, determining by the wireless network node, based on the capability information, a reference signal reporting configuration for the user equipment, for reporting channel state information associated with reference signals transmitted by the first and second transmission and reception points. Finally, the first method may comprise, at step 730, transmitting, by the wireless network node, the reference signal reporting configuration to the user equipment.

[0087] FIG. 8 is a flow graph of a second method in accordance with at least some example embodiments. The phases of the illustrated second method may be performed by UE 110.

[0088] The second method may comprise, at step 810, transmitting by a user equipment, to a wireless network node, capability information indicating whether the user equipment has a capability to perform joint demodulation or separate demodulation of transmission layers received by the user equipment from a first transmission and reception point and a second transmission and reception point. The second method may also comprise, at step 820, receiving, from the wireless network node, a reference signal reporting configuration for the user equipment, for reporting channel state information associated with reference signals received by the user equipment from the first and second transmission and reception points, wherein the reference signal reporting configuration is based on the capability information.

[0089] It is to be understood that the example embodiments 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 example embodiments only and is not intended to be limiting.

[0090] Reference throughout this specification to one example embodiment or an example embodiment means that a particular feature, structure, or characteristic described in connection with the example embodiment is included in at least one example embodiment. Thus, appearances of the phrases “in one example embodiment” or “in an example embodiment” in various places throughout this specification are not necessarily all referring to the same example 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.

[0091] 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 example embodiments and examples may be referred to herein along with alternatives forthe various components thereof. It is understood that such example 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.

[0092] In an example embodiment, an apparatus, comprising for example UE 110 or BS 130, may further comprise means for carrying out the example embodiments described above and any combination thereof. The apparatus may be an apparatus of a cellular communication network, such as a 5G network, and comprise means for operating in the cellular communication network.

[0093] In an example embodiment, a computer program comprising instructions which, when the program is executed by a computer, cause the computer to carry out a method in accordance with the example embodiments described above and any combination thereof. In an example embodiment, a computer program product, embodied on a non- transitory computer readable medium, may be configured to control a processor to perform a process comprising the example embodiments described above and any combination thereof.

[0094] In an example embodiment, an apparatus, comprising for example UE 110 or BS 130, may further comprise at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform the example embodiments described above and any combination thereof. The apparatus may be an apparatus of a cellular communication network, such as a 5G network, and configured to operate in the cellular communication network.

[0095] Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more example embodiments. In the preceding description, numerous specific details are provided, such as examples of lengths, widths, shapes, etc., to provide a thorough understanding of example embodiments of the invention. One skilled in the relevant art will recognize, however, that the invention may 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.

[0096] While the forgoing examples are illustrative of the principles of the example embodiments in one or more particular applications, it will be apparent to those of ordinaryskill in the art that numerous modifications in form, usage and details of implementation may 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.

[0097] 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 dependent 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.

[0098] The expression “at least one of A or B” in this document means A, or B, or both A and B.INDUSTRIAL APPLICABILITY

[0099] At least some example embodiments find industrial application in cellular communication networks, such as 5G networks, and possibly in other cellular communication networks in the future as well.ACRONYMS LIST3GPP 3rd Generation Partnership ProjectADC Anal og-to-Digi tai ConverterBS Base StationCMR Channel Measurement ResourceCSI Channel State InformationD2D Device-to-DeviceDCI Downlink Control InformationFFT Fast Fourier TransformFR Frequency RangeGBBR Group Based Beam ReportingGSM Global System for Mobile communication loT Internet of ThingsLTE Long-Term EvolutionM2M Machine-to-MachineMAC Medium Access ControlMIMO Multiple-Input Multiple-OutputNFC Near-Field CommunicationNR New RadioPCI Physical Cell IdentifierPDSCH Physical Downlink Shared ChannelRAT Radio Access TechnologyRedCap Reduced CapabilityRRC Radio Resource ControlRS Reference SignalsRSRP Received Signal Reference PowerSINR Signal-to-Interfence and Noise RatioSRS Sounding Reference SignalSSB Synchronization Signal BlockTCI Transmit Configuration IndexTRP Transmission and Reception PointUE User EquipmentUI User InterfaceWCDMA Wideband Code Division Multiple AccessWiMAX Worldwide Interoperability for Microwave AccessWLAN Wireless Local Area NetworkREFERENCE SIGNS LIST

Claims

CLAIMS:

1. An apparatus, comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to:- receive, from a user equipment, capability information indicating whether the user equipment has a capability to perform joint demodulation or separate demodulation of transmission layers received by the user equipment from a first transmission and reception point and a second transmission and reception point; and- determine, based on the capability information, a reference signal reporting configuration for the user equipment, for reporting channel state information associated with reference signals transmitted by the first and second transmission and reception points; and- transmit the reference signal reporting configuration to the user equipment.

2. The apparatus according to claim 1, wherein the reference signal reporting configuration is a group based beam reporting configuration.

3. The apparatus according to claim 1 or claim 2, wherein the stored instructions further cause, when executed by the at least one processor, the apparatus at least to:- determine that the reference signal reporting configuration comprises a reference signal received power reporting configuration when the capability information indicates that the user equipment has a capability to perform joint demodulation.

4. The apparatus according to any of the preceding claims, wherein the stored instructions further cause, when executed by the at least one processor, the apparatus at least to:- determine that the reference signal reporting configuration comprises a signal -to- interference and noise ratio reporting configuration when the capability information indicates that the user equipment has a capability to perform separate demodulation.

5. The apparatus according to any of the preceding claims, wherein the stored instructions further cause, when executed by the at least one processor, the apparatus at least to:- determine, based on the capability information, a reference signal configuration for the user equipment, for transmitting the reference signals from the first and second transmission and reception points; and- transmit reference signals from the first and second transmission and reception points to the user equipment in accordance with the reference signal configuration.

6. The apparatus according to claim 5, wherein reference signal resources from the first and second transmission and reception points are configured independently from each other when the capability information indicates that the user equipment has a capability to perform joint demodulation.

7. The apparatus according to any of the preceding claims, wherein a pair of reference signal resources from the first and second transmission and reception points are configured when the capability information indicates that the user equipment has a capability to perform separate demodulation, and wherein one reference signal resource of the pair of reference signal resources is configured for interference measurement.

8. The apparatus according to any of the preceding claims, wherein the stored instructions further cause, when executed by the at least one processor, the apparatus at least to:- cycle through multiple pairs of reference signal resources configured for the first and second transmission and reception points; and- transmit the multiple pairs of reference signal resources in a time sequential manner.

9. The apparatus according to any of claims 6 to 8, wherein the reference signals are channel state information reference signals, and the reference signal resources are 2-ports channel state information reference signal resources.

10. The apparatus according to any of the preceding claims, wherein the stored instructions further cause, when executed by the at least one processor, the apparatus at least to:- transmit, to the user equipment, a received power threshold value for reporting candidate beams; andreceive, from the user equipment, an indication of candidate beams that can be received simultaneously by the user equipment, wherein said candidate beams are beams received by the user equipment with a power higher than the threshold.

11. An apparatus, comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to:- transmit, to a wireless network node, capability information indicating whether the apparatus has a capability to perform joint demodulation or separate demodulation of transmission layers received by the apparatus from a first transmission and reception point and a second transmission and reception point; and- receive, from the wireless network node, a reference signal reporting configuration for the apparatus, for reporting channel state information associated with reference signals received by the apparatus from the first and second transmission and reception points, wherein the reference signal reporting configuration is based on the capability information.

12. The apparatus according to claim 11, wherein the reference signal reporting configuration is a group based beam reporting configuration.

13. The apparatus according to claim 11 or claim 12, wherein the reference signal reporting configuration comprises a reference signal received power reporting configuration when the capability information indicates that the apparatus has a capability to perform joint demodulation.

14. The apparatus according to any of claims 11 to 13, wherein the reference signal reporting configuration comprises a signal-to-interference and noise ratio reporting configuration when the capability information indicates that the apparatus has a capability to perform separate demodulation.

15. A method, comprising:- receiving by a wireless network node, from a user equipment, capability information indicating whether the user equipment has a capability to perform joint demodulation or separate demodulation of transmission layers received by the user equipment from a first transmission and reception point and a second transmission and reception point; and- determining by the wireless network node, based on the capability information, a reference signal reporting configuration for the user equipment, for reporting channel state information associated with reference signals transmitted by the first and second transmission and reception points; and- transmitting, by the wireless network node, the reference signal reporting configuration to the user equipment.

16. A method, comprising:- transmitting by a user equipment, to a wireless network node, capability information indicating whether the user equipment has a capability to perform joint demodulation or separate demodulation of transmission layers received by the user equipment from a first transmission and reception point and a second transmission and reception point; and- receiving by the user equipment, from the wireless network node, a reference signal reporting configuration for the user equipment, for reporting channel state information associated with reference signals received by the user equipment from the first and second transmission and reception points, wherein the reference signal reporting configuration is based on the capability information.

Images