Methods and nodes for tdcp measurements using multiple rx chains

Abstract

There is provided a method in a User Equipment (UE). The method comprises: measuring a normalized channel correlation amplitude (NCA) with receiver diversity, which comprises multiple receiver branches; and reporting, to a network node, an indication of the measured NCA, wherein the reporting is based on the measured NCA, the measured NCA being not lower than a minimum and not higher than a maximum measured values across the multiple receiver branches. A UE for implementing this method is also provided.

Description

Methods and nodes for TDCP measurements using multiple RX chainsRELATED APPLICATIONS

[0001] This application claims the benefits of priority of U.S. Provisional Patent Application No. 63 / 518,933, entitled "TDCP measurements using multiple RX chains" and filed at the United States Patent and Trademark Office (USPTO) on August 11, 2023, which is hereby incorporated by reference in its entirety.TECHNICAL FIELD

[0002] This application generally relates to wireless communications, and more specifically to Time Domain Channel Properties (TDCP) measurements using multiple receiver (Rx) chains.BACKGROUND

[0003] Multi User-Multiple Input Multiple Output (MU-MIMO)

[0004] With multi-user MIMO (MU-MIMO), two or more users in the same cell are coscheduled on the same time-frequency resource(s). That is, two or more independent data streams are transmitted to different User Equipment (UEs) at the same time, and the spatial domain can typically be used to separate the respective streams. By transmitting several streams simultaneously, the capacity of the system can be increased. This, however, comes at the cost of reducing the Signal to Interference & Noise Ratio (SINR) per stream, as the power must be shared between streams and the streams will cause interference to each-other.

[0005] Tracking Reference Signal (TRS)

[0006] Due to oscillator imperfections, transmission and reception may not be synchronized in time and / or frequency, which can cause inter- and intra-symbol interference. In NR, TRS was introduced that can be used by the UE for fine time / frequency synchronization.

[0007] In New Radio (NR) Third Generation Partnership Project (3GPP) specifications, TRS can be configured when Channel State Information (CSI) report setting is not configured or when the higher layer parameter ‘reportQuantity’ in the CSI-ReportConfig information element (IE), associated with all the report settings linked with the CSI-Reference Signal (RS) resource set containing the TRS(s) is set to ‘none’. This means that CSI reporting based on measurements on TRS is not supported in NR.

[0008] TRS is configured via ‘trs-Info’ in the NZP-CSI-RS-ResourceSet IE of 3GPP TS 38.331 which is associated with a CSI-RS resource set, for which the UE can assume that the antenna port with the same port index of the configured NZP CSI-RS resources in the CSI-RS resource set is the same. From the 3GPP specifications perspective, TRS is specified as aspecial kind of Non Zero Power (NZP) CSI-RS where the corresponding NZP CSI-RS resource set containing the TRS(s) has a higher layer parameter ‘trs-info’ set to true.

[0009] TRS is not really a CSI-RS, rather it is a resource set consisting of multiple periodic NZP CSI-RS. More specifically, a TRS consists of four one-port, density-3 CSI-RSs located within two consecutive slots. The CSI-RS within the resource set, can be configured with a periodicity of 10, 20, 40, or 80 ms. Note that the exact set of Resource Elements (Res) used for the TRS CSI-RS may vary. There is always a four-symbol time-domain separation between the two CSI-RS within a slot. NR also supports aperiodic TRS.

[0010] For Long Term Evolution (LTE), the cell-specific reference signal (CRS) served the same purpose as the TRS as LTE CRS can be used for synchronization but it can also be used for CSI reporting, which is not supported for TRS in NR. However, compared to the LTE CRS, the TRS in NR implies much less overhead, only having one antenna port and only being present in two slots every TRS period.

[0011] CSI framework in NR

[0012] In NR, a UE can be configured with multiple CSI reporting settings and multiple CSI-RS resource settings. Each resource setting can contain multiple resource sets, and each resource set can contain up to 8 CSI-RS resources. For each CSI reporting setting, a UE feeds back a CSI report.

[0013] Each CSI reporting setting contains at least the following information:

[0014] - A CSI-RS resource set for channel measurement;

[0015] - An IMR resource set for interference measurement;

[0016] - Optionally, a CSI-RS resource set for interference measurement;

[0017] - Time-domain behavior, i.e., periodic, semi-persistent, or aperiodic reporting;

[0018] - Frequency granularity, i.e., wideband or subband;

[0019] - CSI parameters to be reported such as Rank Indicator (RI), Precoding MatrixIndicator (PMI), Channel Quality indicator (CQI), and CSI-RS resource indicator (CRI) in case of multiple CSI-RS resources in a resource set;

[0020] - Codebook types, i.e., Type I or II, and codebook subset restriction;

[0021] - Measurement restriction;

[0022] - Subband size. One out of two possible subband sizes is indicated, the value range depends on the bandwidth of the bandwidth part (BWP). One CQI / PMI (if configured for subband reporting is fed back per subband).

[0023] Rel-18 specification of TRS based TDCP reporting

[0024] The TDCP feature defines UE estimation and reporting of the wideband normalized correlation (WNC) between two TRS symbols separated by D symbols. This should be interpreted as an estimate of the normalized channel correlation in time as given by

[0026] where h„(t) is the channel for subcarrier n at time t and At corresponds to the D symbols separating the two TRS symbols. The correlation lag At is configurable and can take the values 4 OFDM symbols, 1 slot, 2 slots, 3 slots, 4 slots, 5 slots, 6 slots and 10 slots (10 slots is applicable only to 30kHz subcarrier spacing). The maximum correlation lag a UE supports is subject to UE capability. A UE which supports TDCP supports at least correlation lags up to 1 slot.

[0027] The UE can be configured to report the results of the channel correlation for up to four different correlation lag values. The maximum number of correlation lags for which the correlation can be reported is subject to UE capabilities. A UE which supports TDCP may support reporting of the correlation for only one correlation lag.

[0028] The UE can be configured to report both the amplitude (e.g. wideband normalized correlation amplitude (WNCA)) and the phase (e.g. wideband normalized correlation phase (WNCP)) of the correlation A(t, At) . Reporting of the phase is, however, subject to UE capability.

[0029] For correlation lags longer than one slot, the UE measurement has to be performed across the TRS bursts of two different TRSs. The two TRSs should have a relative slot offset corresponding to the correlation lag At. The TRS which is anyway configured for tracking purposes may be reused also for TDCP, but one additional TRS needs to be configured. The extra TRS could have a longer periodicity than the TRS used for tracking in order to save overhead. To support estimation of the channel correlation over a delay of 4 OFDM symbols or 1 slot, it’s sufficient to configure a single dual slot TRS. To support a longer correlation delay, it is, however, necessary to configure two TRSs with a relative time offset corresponding to the wanted correlation delay.

[0030] For the correlation lags 4 OFDM symbols, and 1 slot, the UE measurement can be made within one two-slot TRS burst. This means that only the TRS which is anyway configured fortracking purposes is needed.

[0031] In RANI, it has not yet been specified how the UE should perform the TDCP measurement in case of receive (RX) diversity, i.e. how it should handle multiple RX chains. In RANI# 113 meeting, RANI made the following agreement.

[0032] Agreement:

[0033] For the Rel-18 TRS-based TDCP reporting, for a configured value ofY and a set of configured delayvalues {Di, ... , DY}, for the n-th delay Dn(n=l, ... , Y), the respective TDCP calculation is defined as wideband normalized correlation between two TRS symbols separated by Dnsymbols.

[0034] - Send a LS to RAN4 to solicit their inputs on whether additional description / definition is needed, e.g. averaging across RX ports.

[0035] The LS (Liaison statement) to RAN4 was sent in Rl-2306137.

[0036] Use cases for the NR Rel. 18 TDCP feature

[0037] One use case for TDCP reporting is to enable the gNB to select a transmission scheme that is more robust to channel ageing when the channel varies fast. Lor instance, based on the TRS-based TDCP reported by the UE to the gNB, the gNB may need to decide whether the precoder for the UE should be based on CSI obtained from uplink measurements or from CSI feedback obtained from the UE. Another example is that the gNB may need to decide whether the precoder to schedule the UE should be based on Type I CSI feedback obtained from the UE or Type II CSI feedback obtained from the UE.

[0038] It has been shown that reciprocity-based precoding has better performance at 3 km / h for both Single User (SU)-MIMO and MU-MIMO, for example. However, at UE speeds around 10 km / h, the feedback-based precoding has better performance. Hence, the feedbackbased precoding is more robust to rapidly varying channels. A speed of 10 km / h corresponds to a channel coherence time which is longer than two slots.

[0039] Comparisons of the performance between precoding based on Type I and Type II CSI have been performed. The results show that Type II CSI gives better performance at 3 km / h but at UE speeds around 10 km / h and higher, type I gives better performance.

[0040] These results show that it could be beneficial to select precoding scheme based on some parameter that is related to the UE speed. It should be noted that it is not the UE speed per se that is the fundamental parameter in this context. Rather, it is how fast the channel varies which depends on the UE speed but also on the angle between the UE velocity vector and the propagation paths seen from the UE. Therefore, selection of precoding scheme based on some time domain channel property such as coherence time or autocorrelation is a more suitable parameter.

[0041] Other use cases for the TDCP report include:

[0042] • Switching between reciprocity-based precoding and CSI based precoding;

[0043] • Switching between different SRS periodicities;

[0044] • Switching between different CSI RS and / or CSI reporting periodicities;

[0045] • Switching between different number of additional DMRS symbols.

[0046] UE TDCP estimation

[0047] UE measurement and reporting of time domain correlation based on TRS samples across different time lags is an efficient way to report TDCP based on TRS.

[0048] In order to define the time domain correlation measurement across TRS samples, let X([n], n = 0,1, ... , 1V — 1 be the received frequency domain TRS samples after matched filtering and after removing the reference signal sequence. Index I denotes the different Orthogonal Frequency Division Multiplexing (OFDM) symbols carrying the TRSs used for the correlation estimation. Note that the TRSs used for the correlation estimation may be located in the same or different slots. The starting point in time of the OFDM symbol I is given by tL(to be precise ttdenotes the start of the non-CP part of the OFDM symbol). Index n denote TRS sample index (assumed to be proportional to subcarrier index).

[0049] Let Pm(u), m = 1 ... M, u = 1,2 be the / -indices of M symbol pairs to use for the estimation of the correlation for a delay T = tPm^2) — tPm^y It is assumed that the M symbol pairs are separated by the same distance in time.

[0050] In one example, a low-complexity estimate of the normalized time domain correlation for a delay T is calculated in the frequency domain as

[0052] or alternatively using geometric normalization as

[0054] In another example, the inverse DFT is calculated for each OFDM symbol I

[0055] y([ / c] = ifft^n])

[0056] The estimate of the normalized correlation for time delay T is calculated as

[0058] or alternatively using geometric normalization as

[0060] where the sum overtime samples is over sets T(m) defined to suppress noise, e.g. by using a noise threshold such as e.g.

[0062] where Opm(i) are noise estimates.

[0063] Note that at low speeds the change in the channel is small and the change in correlation at different delays within a TRS burst is quite small.

[0064] As the change in correlation at different delays within a TRS burst is quite small for low velocities, intra TRS burst measurements are not enough to distinguish between different velocities in the low velocity region. Therefore, support for measuring and reporting correlation for time delays corresponding to multiple TRS bursts is needed.SUMMARY

[0065] There currently exist certain challenge(s). How the UE should handle multiple RX branches when estimating the channel correlation (i.e., the wideband normalized correlation) is an open issue. This makes the channel correlation measure ambiguous and also makes it impossible to define requirements and tests of the TDCP feature, e.g., for the channel correlation accuracy. Without defining the requirements and tests, the network (NW) would not know whether the results reported by the UE are reliable or not.

[0066] UE antennas and UE antenna panels and the implementation of UE RX branches may vary a lot between different UEs. This makes it hard to define the handling of RX branches in a way that fits all possible UE implementations.

[0067] Certain aspects of the disclosure and their embodiments may provide solutions to these or other challenges.

[0068] According to one aspect, there is provided a method in a UE of measuring or estimating a normalized channel correlation amplitude (NCA) with receiver diversity (e.g. 2 or more receiver branches) based on one or more rules; and using the results of the measured / estimated channel correlation amplitude for performing one or more tasks e.g. transmitting the results to a network node, using the results for enhancing channel estimation and / or for adapting its receiver configuration etc.

[0069] As a note, the NCA may interchangeably be called as or refer to as any of: WNCA, time domain correlation properties or TDCP, normalized time domain correlation properties or normalized time domain channel correlation properties (NTDCP), time domain correlationamplitude or time domain channel correlation amplitude (TDCA), normalized time domain correlation amplitude or normalized time domain channel correlation amplitude (NTDCA), etc. Also, it has already been decided in RAN 1 that the UE should measure and report WNCA but it hasn’t been defined or described how the UE should handle multiple receiver branches.

[0070] The rules for the UE to estimate the NCA with receiver diversity can be predefined, configured by a network node (e.g. the serving base station).

[0071] In one example, the rules can be realized or enforced in the UE by:

[0072] - Putting requirements on the accuracy of the WNCA in the TDCP measurement report by formulating requirements for the case that the same RX signal is applied to all UE antennas. This allows a large UE implementation flexibility with regards to UE antennas, RX branches and for how to measure the WNCA over multiple RX branches while still making it possible to put stringent requirements.

[0073] - Testing the accuracy of the WNCA in the TDCP measurement report by applying the same RX signal to all UE antennas.

[0074] According to a second aspect, there is provided a method in a UE. The method comprises measuring a NCA with receiver diversity, which comprises multiple receiver branches; and reporting, to a network node, an indication of the measured NCA, wherein the reporting is based on the measured NCA, the measured NCA being not lower than a minimum and not higher than a maximum measured values across the multiple receiver branches.

[0075] According to a third aspect, there is provided a method in a network node (e.g. serving base station of the UE). The method comprises: configuring a UE to measure a NCA with receiver diversity, which comprises multiple branches; and receiving an indication of a measured NCA, wherein the measured NCA is not lower than a minimum and not higher than a maximum measured values across the multiple receiver branches.

[0076] Certain embodiments may provide one or more of the following technical advantage(s).

[0077] The proposed solutions herein allow flexibility in the implementation of UE antennas, antenna panels, RX-chains and in the use of these to estimate the TDCP correlation amplitude, while still making it possible to test the TDCP feature and its measurement accuracy.

[0078] The flexible RX chain handling allows for higher measurement accuracy and thus better performance for use cases of the TDCP feature.

[0079] A measurement definition is given restricting the usage of RX -branches when estimating the correlation amplitude so that it can be tested while at the same time leaving room for UE implementation flexibility.

[0080] The method gives performance improvement for the above use-cases for the case when RX receiver diversity is used by the UE.BRIEF DESCRIPTION OF THE DRAWINGS

[0081] Exemplary embodiments will be described in more detail with reference to the following figures, in which:

[0082] Fig. 1 illustrates a flow of a method in a UE, according to some embodiments.

[0083] Fig. 2 illustrates a flow of a method in a UE, according to some embodiments.

[0084] Fig. 3 illustrates a flow of a method in a network node, according to some embodiments.

[0085] Fig. 4 shows an example of a communication system, according to an embodiment.

[0086] Fig. 5 shows a schematic diagram of a UE, according to an embodiment.

[0087] Fig. 6 shows a schematic diagram of a network node, according to an embodiment.

[0088] Fig. 7 illustrates a block diagram illustrating a virtualization environment.DETAILED DESCRIPTION

[0089] Some of the embodiments contemplated herein will now be described more fully with reference to the accompanying drawings. Embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art.

[0090] Generally stated, embodiments of this disclosure provide that, in UE measuring and reporting the wideband normalized channel correlation amplitude (WNCA) where, in the case of receive diversity, the reported WNCA should be lower than or equal to the WNCA of the individual receiver branch that has the highest WNCA; and higher than or equal to the individual receiver branch that has the lowest WNCA. The embodiments allow to put requirements on the accuracy of the WNCA in the TDCP measurement report by formulating requirements for the case that the same RX signal is applied to all UE antennas. They also allow to test the accuracy of the WNCA in the TDCP measurement report by applying the same RX signal to all UE antennas.

[0091] Measurement quantity definition with regards to handling of multiple RX branches

[0092] Fig. 1 illustrates a method 100 in a UE. The method 100 comprises:

[0093] Step 110: measuring or estimating a normalized channel correlation amplitude (NCA) (e.g. WNCA with receiver diversity (e.g. 2 or more Rx branches) based on one or more rules; and

[0094] Step 120: using the results of the measured / estimated channel correlation amplitude for performing one or more tasks.

[0095] Examples of the tasks can be:

[0096] - transmitting the results to a network node e.g. to a serving base station,

[0097] - using the results for enhancing channel estimation,

[0098] - using the results for adapting its receiver configuration etc.

[0099] The one or more rules (of step 110) can be pre-defined and / or configured by a network node (e.g. the serving base station). The rules are described below with examples:

[0100] In a first example of the rule, the UE determines based on one or more criteria a set of receivers (i.e. Rx branches) for performing the NCA with the receiver diversity (e.g. 2 or more Rx branches). The UE then performs the NCA using the determined set of its Rx branches. The determined set of the receivers may comprise a subset of the receivers, or all the receivers supported by the UE. For example, the UE may support 4 receiver (Rx) branches, but it may use only 2 Rx branches for performing the NCA. In one example, the UE may support 8 Rx branches, but it may use only 2 or 4 Rx branches for performing the NCA. In one example, the UE may use all its supported Rx branches for performing the NCA. In general, the UE supports N Rx branches and uses M Rx branches for performing the NCA; where (M<N). Examples of the criteria for determining N out of M Rx branches and which of the N branches for performing the NCA are given below:

[0101] In one example of the criterion, the UE uses the same receivers which are being used or has been used in the last XI 1 number of time resources or expected to be used in the next X12 number of time resources by the UE for receiving certain type of reference signals (e.g. SSB, TRS, CSI-RS, DMRS, etc.). The RSs may be received by the UE for one or more radio operations or radio preparatory tasks, e.g. time and / or frequency tracking, fine time tuning, channel estimation etc. Examples of the time resources are symbol, slot, subframe, frame, etc. For example, if the UE has 4 Rx (Rxl, Rx2, Rx3 and Rx4) and is using 2 Rx branches (e.g. Rx3 and Rx4) for receiving certain type of RSs, then according to this criterion the UE also uses the same 2 Rx branches (e.g. Rx3 and Rx4) for performing the NCA. The parameters XI 1 and X12 can be pre-defined or configured by the network node.

[0102] In another example of the criterion, the UE uses the same receivers which are being used or has been used in the last X21 number of time resources or expected to be used in thenext X22 number of time resources by the UE for performing certain type of measurements (e g. CSI, Ll-RSRP, Ll-SINR, RSRP, RSRQ, etc ). For example, if the UE has 4 Rx (Rxl- Rx4) and is using 2 Rx branches (e.g. Rx2 and Rx3) for performing certain type of measurements (e.g. CQI) then according to this criterion the UE also uses the same 2 Rx branches (e.g. Rx2 and Rx3) for performing the NCA. The parameters X21 and X22 can be pre-defined or configured by the network node.

[0103] In another example of the criterion, the number of receivers used by the UE for performing the NCA depends on a relation between the received signal level (RSL) at the UE and a RSL threshold. Examples of the RSL are received signal strength (RSS), received signal quality (RSQ), etc. Examples of RSS are pathloss, RSRP, Ll-RSRP etc. Examples of RSQ are CQI, SNR, SINR, RSRQ, Ll-SINR, etc. In one example, the UE uses not more than X31 number of Rx branches for performing the NCA if the RSL is above a certain threshold (Hl 1). In another example, the UE uses at least X32 number of Rx branches for performing the NCA if the RSL is below a certain threshold (H12). In another example, the UE may use any number of Rx branches for performing the NCA if the RSL is above a certain threshold (H13) but below another threshold (H14). The parameters X31, X32, Hl l, H12, H13 and H14 can be predefined or configured by the network node.

[0104] In another example of the criterion, the number of receivers used by the UE for performing the NCA depends on the HARQ feedback (e.g. number of ACKs and / or NACKs) related to downlink data reception (e.g. Physical Downlink Shared Channel (PDSCH)) by the UE. For example, if the number of NACKs transmitted by the UE for DL data reception within a certain time period (T11) is below a certain threshold (H21), then the UE uses not more than X41 number of receivers for performing the NCA. In another example, if the number of NACKs transmitted by the UE for DL data reception within a certain time period (T12) is above a certain threshold (H22), then the UE uses at least X42 number of receivers for performing the NCA. The parameters X41, X42, H21, H22, Ti l and T12 can be pre-defined or configured by the network node.

[0105] In another example of the criterion, the Rx branches used by the UE for performing the NCA depends on the Rx branches being used or has been recently used or is going to be used by the UE for receiving certain data channel, e.g. PDSCH, PDCCH, etc. For example, the UE uses the same receivers which are being used or has been used in the last X51 number of time resources or expected to be used in the next X52 number of time resources by the UE for receiving certain type of data channel (e.g. PDCCH, PDSCH, PBCH, etc.). For example, if the UE having 4 Rx (Rxl, Rx2, Rx3 and Rx4) and is using 2 Rx branches (e.g. Rx2 and Rx4) forreceiving the PDSCH or PDCCH, then according to this criterion the UE also uses the same 2 Rx branches (e.g. Rx2 and Rx4) for performing the NCA. The parameters X51 and X52 can be pre-defined or configured by the network node.

[0106] In a second example of the rule, the UE determines based on one or more criteria a relation between the NCA to be performed by the UE with receiver diversity and one or more reference NCA values. The UE may further obtain the set of receivers for performing the NCA using the receiver diversity according to the first rule above. The UE performs / estimates / measures / obtains the NCA based on the determined relation and further uses the estimated NCA value for one or more tasks, e.g. transmits the results to the network node. Examples of the reference NCA value are:

[0107] - NCA obtained / estimated by the UE using single / individual receiver branch which gives the highest NCA value,

[0108] - NCA obtained / estimated by the UE single / individual receiver branch which gives the lowest NCA value,

[0109] - average NCA value of two or more receiver branches,

[0110] - pre -defined NCA value,[oni] - NCA value configured by the network node, etc.

[0112] Some specific examples of this second rule are given below:

[0113] In one example, the estimated / measured value of the NCA performed with the receiver diversity is not larger than a first NCA reference value (Nrefl). In this case the UE further reports the estimated NCA value which is not larger than Nrefl . In one example, Nrefl is the NCA performed with the single / individual receiver branch that gives the highest value of the NCA among a set (Sr) of the receiver branches. In one example, the Sr comprises the receivers used by the UE for performing the NCA with receiver diversity. In another example, the Sr comprises all the receivers supported by the UE.

[0114] In another example, the estimated / measured value of the NCA performed with the receiver diversity is not lower than a second NCA reference value (Nref2). In this case, the UE further reports the estimated NCA value which is not lower than Nref2. In one example, Nref2 is the NCA performed with the single / individual receiver branch that gives the lowest value of the NCA among the set of its receiver branches, Sr, which is described in the previous example .

[0115] In another example, the estimated / measured value of the NCA performed with the receiver diversity is not larger than Nrefl and not lower than Nref2. In this case, the UE further reports the estimated NCA value which is not larger than Nrefl and is not lower than Nref2. Nrefl and Nref2 are the same as described in the previous examples.

[0116] In another example, the UE reports / transmits the estimated / measured NCA performed by the UE with the receiver diversity to the network node based on a relation between the estimated NCA value and a certain NCA reference value. In this example, the NCA reference value can be an average value estimated using a certain number of receivers (e.g. subset of receivers, all receivers, etc.), pre-defined or configured by the network node. In one example of the relation, the UE transmits the estimated / measured NCA performed with the receiver diversity to the network node provided that the estimated NCA value is not larger than a third NCA reference value (Nrcf3). In another example of the relation, the UE transmits the estimated / measured NCA performed with the receiver diversity to the network node provided that the estimated NCA value is not lower than a fourth NCA reference value (Nref4). In yet another example of the relation, the UE transmits the estimated / measured NCA performed with the receiver diversity to the network node provided that the estimated NCA value is not larger than Nref3 and is not lower than Nref4.

[0117] In one specific example, the UE estimates and reports the NCA (e.g. wideband NCA) according to one or more of the following principles / rules:

[0118] If receiver diversity is in use, the reported WNCA is required: not to be higher than all the WNCA for the individual receiver branches, and not be lower than all the WNCA for the individual receiver branches.

[0119] An alternative way to say the same thing is as follows: if receiver diversity is in use, there should be at least one individual receiver branch for which the reported WNCA is equal to or lower than the WNCA for that individual receiver branch, and there should be at least one individual receiver branch for which the reported WNCA is equal to or higher than the WNCA for that individual receiver branch.

[0120] In a further alternative, the condition may be captured as follows: if receiver diversity is in use, the reported WNCA is required to be lower than or equal to the WNCA of the individual receiver branch that has the highest WNCA; and higher than or equal to the WNCA of the individual receiver branch that has the lowest WNCA.

[0121] In 3GPP specifications, this may be captured as any one of the following alternatives:

[0122] Alternative 1: For frequency range (FR) 1, the reference point for the WNCA between two TRS symbols separated by Dn symbols shall be the antenna connector of the UE. For FR 2, the WNCA shall be measured based on the combined signal from antenna elements corresponding to a given receiver branch. For FR 1 and FR 2, if receiver diversity is in use by the UE, the reported WNCA value shall not be higher than all the corresponding WNCA of theindividual receiver branches, and the reported WNCA value shall not be lower than all the corresponding WNCA of the individual receiver branches.

[0123] Alternative 2: For FR 1, the reference point for the WNCA between two TRS symbols separated by Dn symbols shall be the antenna connector of the UE. For FR 2, the WNCA shall be measured based on the combined signal from antenna elements corresponding to a given receiver branch. For FR 1 and FR 2, if receiver diversity is in use by the UE, the WNCA of at least one of the individual receiver branches shall be lower than or equal to the reported WNCA value.

[0124] Alternative 3: For FR 1, the reference point for the WNCA between two TRS symbols separated by Dn symbols shall be the antenna connector of the UE. For FR 2, the WNCA shall be measured based on the combined signal from antenna elements corresponding to a given receiver branch. For FR 1 and FR 2, if receiver diversity is in use by the UE, the reported WNCA shall be lower than or equal to the individual receiver branch that has the highest measured WNCA, and be higher than or equal to the individual receiver branch that has the lowest measured WNCA.

[0125] In another example, Fig. 2 illustrates an exemplary flow chart of a method 200. Method 200 is performed in a UE, such as UE 412 of Fig. 4 or UE 500 of Fig. 5. Method 200 comprises:

[0126] Step 210: measuring a normalized channel correlation amplitude (NCA) with receiver diversity, which comprises multiple receiver branches; and

[0127] Step 220: reporting, to a network node, an indication of the measured NCA, wherein the reporting is based on the measured NCA, the measured NCA being not lower than a minimum and not higher than a maximum measured values across the multiple receiver branches.

[0128] In some examples, further comprising determining, based on one or more criteria, a set of receivers for measuring the NCA with the receiver diversity and wherein measuring the NCA is based on the determined set of receivers. In some examples, the one or more criteria comprise using receivers which are used for receiving a certain type of reference signals or using receivers which are used for performing a certain type of measurements. In some examples, the reference signals are TRS. In some examples, the NCA comprises time domain channel properties (TDCP).

[0129] It should be noted that the examples described under method 100 may be applicable to method 200 as well.

[0130] Now, turning to Fig. 3, a method 300 in a network node for performing / measuring NCA will be described. The method is implemented in a network node (e.g. base station, access point, etc.), such as network node 410 of Fig. 5 or network node 600 of Fig. 6, serving the UE 500 or 412. Method 300 comprises:

[0131] Step 310: configuring a UE to measure a normalized channel correlation amplitude (NCA) with receiver diversity, which comprises multiple branches;

[0132] Step 320: receiving an indication of a measured NCA, wherein the measured NCA is not lower than a minimum and not higher than a maximum measured values across the multiple receiver branches; and

[0133] Step 330 (optionally): Using the received indication of the measured NCA for performing one or more operational tasks.

[0134] Further details regarding the above steps are provided below.

[0135] In step 310, the network node may configure the UE using a signaling message (e.g. via RRC, MAC-CE, etc.) to estimate / measure the NCA (e.g. WNCA) according to one or more configuration parameters provided to the UE in the signaling message. Examples of such parameters are symbol pairs to use for the estimation of the channel correlation (e.g. NCA), channel correlation lag (e.g. Y1 symbols, Y2 slots etc.) between the symbol pairs, etc. The network may also configure the UE with one or more parameters (e.g. thresholds, reference values, etc.) for determining the receivers to be used for estimating / measuring the NCA with receiver diversity. The network node may further configure the UE with the reporting mechanism for transmitting an indication of the measured NCA to the network node. Examples of the reporting mechanisms are periodic reporting, aperiodic reporting (e.g. once or certain number of times, etc.), reporting only when the NCA changes with regards to a certain reference value / threshold, etc.

[0136] The network node obtains the results related to the NCA (e.g. WNCA) or the indication of the measured NCA performed by the UE with receiver diversity by receiving it from the UE via a signaling message, e.g. via RRC, MAC-CE, etc.

[0137] The network node may optionally use the measured NCA for performing one or more operational tasks, such as:

[0138] - adapting the scheduling of data to the UE (e.g. limiting maximum MCS to certain value),

[0139] - modifying one or more transmission parameters (e.g. changing power offset between the DL channel and the reference signals, increasing or decreasing the transmission power of data channel such as PDSCH, etc.),

[0140] - modifying the configuration of one or more parameters related to the NCA estimation, e.g. changing the symbol pairs to use for the estimation of the channel correlation and / or the channel correlation lag, etc.

[0141] - modifying the configuration of one or more reference signals (e.g. TRS, DMRS etc.),

[0142] - modifying antenna mode configuration (e.g. increase or decrease the MIMO layers, change the type of MIMO scheme, etc.), etc.

[0143] Fig. 4 shows an example of a communication system 400 in accordance with some embodiments.

[0144] In the example, the communication system 400 includes a telecommunication network 402 that includes an access network 404, such as a radio access network (RAN), and a core network 406, which includes one or more core network nodes 408. The access network 404 includes one or more access network nodes, such as network nodes 410a and 410b (one or more of which may be generally referred to as network nodes 410), or any other similar 3GPP access nodes or non-3GPP access points. Moreover, as will be appreciated by those of skill in the art, a network node is not necessarily limited to an implementation in which a radio portion and a baseband portion are supplied and integrated by a single vendor. Thus, it will be understood that network nodes include disaggregated implementations or portions thereof. For example, in some embodiments, the telecommunication network 402 includes one or more Open-RAN (ORAN) network nodes. An ORAN network node is a node in the telecommunication network 402 that supports an ORAN specification (e.g., a specification published by the O-RAN Alliance, or any similar organization) and may operate alone or together with other nodes to implement one or more functionalities of any node in the telecommunication network 402, including one or more network nodes 410 and / or core network nodes 408.

[0145] Examples of an ORAN network node include an open radio unit (O-RU), an open distributed unit (O-DU), an open central unit (O-CU), including an O-CU control plane (O- CU-CP) or an O-CU user plane (O-CU-UP), a RAN intelligent controller (near-real time or non-real time) hosting software or software plug-ins, such as a near-real time control application (e.g., xApp) or a non-real time control application (e.g., rApp), or any combination thereof (the adjective “open” designating support of an ORAN specification). The network node may support a specification by, for example, supporting an interface defined by the ORAN specification, such as an Al, Fl, Wl, El, E2, X2, Xn interface, an open fronthaul user plane interface, or an open fronthaul management plane interface. Moreover, an ORAN accessnode may be a logical node in a physical node. Furthermore, an ORAN network node may be implemented in a virtualization environment (described further below) in which one or more network functions are virtualized. For example, the virtualization environment may include an O-Cloud computing platform orchestrated by a Service Management and Orchestration Framework via an 0-2 interface defined by the O-RAN Alliance or comparable technologies. The network nodes 410 facilitate direct or indirect connection of user equipment (UE), such as by connecting UEs 412a, 412b, 412c, and 412d (one or more of which may be generally referred to as UEs 412) to the core network 406 over one or more wireless connections.

[0146] Example wireless communications over a wireless connection include transmitting and / or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and / or other types of signals suitable for conveying information without the use of wires, cables, or other material conductors. Moreover, in different embodiments, the communication system 400 may include any number of wired or wireless networks, network nodes, UEs, and / or any other components or systems that may facilitate or participate in the communication of data and / or signals whether via wired or wireless connections. The communication system 400 may include and / or interface with any type of communication, telecommunication, data, cellular, radio network, and / or other similar type of system.

[0147] The UEs 412 may be any of a wide variety of communication devices, including wireless devices arranged, configured, and / or operable to communicate wirelessly with the network nodes 410 and other communication devices. Similarly, the network nodes 410 are arranged, capable, configured, and / or operable to communicate directly or indirectly with the UEs 412 and / or with other network nodes or equipment in the telecommunication network 402 to enable and / or provide network access, such as wireless network access, and / or to perform other functions, such as administration in the telecommunication network 402.

[0148] In the depicted example, the core network 406 connects the network nodes 410 to one or more hosts, such as host 416. These connections may be direct or indirect via one or more intermediary networks or devices. In other examples, network nodes may be directly coupled to hosts. The core network 406 includes one more core network nodes (e.g., core network node 408) that are structured with hardware and software components. Features of these components may be substantially similar to those described with respect to the UEs, network nodes, and / or hosts, such that the descriptions thereof are generally applicable to the corresponding components of the core network node 408. Example core network nodes include functions of one or more of a Mobile Switching Center (MSC), Mobility Management Entity (MME), Home Subscriber Server (HSS), Access and Mobility Management Function (AMF),Session Management Function (SMF), Authentication Server Function (AUSF), Subscription Identifier De-concealing function (SIDF), Unified Data Management (UDM), Security Edge Protection Proxy (SEPP), Network Exposure Function (NEF), and / or a User Plane Function (UPF).

[0149] The host 416 may be under the ownership or control of a service provider other than an operator or provider of the access network 404 and / or the telecommunication network 402, and may be operated by the service provider or on behalf of the service provider. The host 416 may host a variety of applications to provide one or more service. Examples of such applications include live and pre-recorded audio / video content, data collection services such as retrieving and compiling data on various ambient conditions detected by a plurality of UEs, analytics functionality, social media, functions for controlling or otherwise interacting with remote devices, functions for an alarm and surveillance center, or any other such function performed by a server.

[0150] As a whole, the communication system 400 of Fig. 4 enables connectivity between the UEs, network nodes, and hosts. In that sense, the communication system may be configured to operate according to predefined rules or procedures, such as specific standards that include, but are not limited to: Global System for Mobile Communications (GSM); Universal Mobile Telecommunications System (UMTS); Long Term Evolution (LTE), and / or other suitable 2G, 3G, 4G, 5G standards, or any applicable future generation standard (e.g., 6G); wireless local area network (WLAN) standards, such as the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards (WiFi); and / or any other appropriate wireless communication standard, such as the Worldwide Interoperability for Microwave Access (WiMax), Bluetooth, Z-Wave, Near Field Communication (NFC) ZigBee, LiFi, and / or any low-power wide-area network (LPWAN) standards such as LoRa and Sigfox.

[0151] In some examples, the telecommunication network 402 is a cellular network that implements 3GPP standardized features. Accordingly, the telecommunications network 402 may support network slicing to provide different logical networks to different devices that are connected to the telecommunication network 402. For example, the telecommunications network 402 may provide Ultra Reliable Low Latency Communication (URLLC) services to some UEs, while providing Enhanced Mobile Broadband (eMBB) services to other UEs, and / or Massive Machine Type Communication (mMTC)ZMassive loT services to yet further UEs.

[0152] In some examples, the UEs 412 are configured to transmit and / or receive information without direct human interaction. For instance, a UE may be designed to transmit information to the access network 404 on a predetermined schedule, when triggered by aninternal or external event, or in response to requests from the access network 404. Additionally, a UE may be configured for operating in single- or multi -RAT or multi-standard mode. For example, a UE may operate with any one or combination of Wi-Fi, NR and LTE, i.e. being configured for multi-radio dual connectivity (MR-DC), such as E-UTRAN (Evolved-UMTS Terrestrial Radio Access Network) NR - Dual Connectivity (EN-DC).

[0153] In the example, the hub 414 communicates with the access network 404 to facilitate indirect communication between one or more UEs (e.g., UE 412c and / or 412d) and network nodes (e.g., network node 410b). In some examples, the hub 414 may be a controller, router, content source and analytics, or any of the other communication devices described herein regarding UEs. For example, the hub 414 may be a broadband router enabling access to the core network 406 for the UEs. As another example, the hub 414 may be a controller that sends commands or instructions to one or more actuators in the UEs. Commands or instructions may be received from the UEs, network nodes 410, or by executable code, script, process, or other instructions in the hub 414. As another example, the hub 414 may be a data collector that acts as temporary storage for UE data and, in some embodiments, may perform analysis or other processing of the data. As another example, the hub 414 may be a content source. For example, for a UE that is a VR headset, display, loudspeaker or other media delivery device, the hub 414 may retrieve VR assets, video, audio, or other media or data related to sensory information via a network node, which the hub 414 then provides to the UE either directly, after performing local processing, and / or after adding additional local content. In still another example, the hub 414 acts as a proxy server or orchestrator for the UEs, in particular if one or more of the UEs are low energy loT devices.

[0154] The hub 414 may have a constant / persistent or intermittent connection to the network node 410b. The hub 414 may also allow for a different communication scheme and / or schedule between the hub 414 and UEs (e.g., UE 412c and / or 412d), and between the hub 414 and the core network 406. In other examples, the hub 414 is connected to the core network 406 and / or one or more UEs via a wired connection. Moreover, the hub 414 may be configured to connect to an M2M service provider over the access network 404 and / or to another UE over a direct connection. In some scenarios, UEs may establish a wireless connection with the network nodes 410 while still connected via the hub 414 via a wired or wireless connection. In some embodiments, the hub 414 may be a dedicated hub - that is, a hub whose primary function is to route communications to / from the UEs from / to the network node 410b. In other embodiments, the hub 414 may be a non-dedicated hub - that is, a device which is capable of operating to route communications between the UEs and network node 410b, but which isadditionally capable of operating as a communication start and / or end point for certain data channels.

[0155] Fig. 5 shows a UE 500 in accordance with some embodiments. As used herein, a UE refers to a device capable, configured, arranged and / or operable to communicate wirelessly with network nodes and / or other UEs. Examples of a UE include, but are not limited to, a smart phone, mobile phone, cell phone, voice over IP (VoIP) phone, wireless local loop phone, desktop computer, personal digital assistant (PDA), wireless cameras, gaming console or device, music storage device, playback appliance, wearable terminal device, wireless endpoint, mobile station, tablet, laptop, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), smart device, wireless customer-premise equipment (CPE), vehicle, vehicle-mounted or vehicle embedded / integrated wireless device, etc. Other examples include any UE identified by the 3GPP, including a narrow band internet of things (NB-IoT) UE, a machine type communication (MTC) UE, and / or an enhanced MTC (eMTC) UE.

[0156] A UE may support device-to-device (D2D) communication, for example by implementing a 3GPP standard for sidelink communication, Dedicated Short-Range Communication (DSRC), vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), orvehicle- to-everything (V2X). In other examples, a UE may not necessarily have a user in the sense of a human user who owns and / or operates the relevant device. Instead, a UE may represent a device that is intended for sale to, or operation by, a human user but which may not, or which may not initially, be associated with a specific human user (e.g., a smart sprinkler controller). Alternatively, a UE may represent a device that is not intended for sale to, or operation by, an end user but which may be associated with or operated for the benefit of a user (e.g., a smart power meter).

[0157] The UE 500 includes processing circuitry 502 that is operatively coupled via a bus 504 to an input / output interface 506, a power source 508, a memory 510, a communication interface 512, and / or any other component, or any combination thereof. Certain UEs may utilize all or a subset of the components shown in Fig. 5. The level of integration between the components may vary from one UE to another UE. Further, certain UEs may contain multiple instances of a component, such as multiple processors, memories, transceivers, transmitters, receivers, etc.

[0158] The processing circuitry 502 is configured to process instructions and data and may be configured to implement any sequential state machine operative to execute instructions stored as machine-readable computer programs in the memory 510. The processing circuitry 502 may be implemented as one or more hardware-implemented state machines (e.g., indiscrete logic, field-programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), etc.); programmable logic together with appropriate firmware; one or more stored computer programs, general-purpose processors, such as a microprocessor or digital signal processor (DSP), together with appropriate software; or any combination of the above. For example, the processing circuitry 502 may include multiple central processing units (CPUs). Further, the processing circuitry 502 is configured to perform any steps of method 100 of Fig. 1 and of method 200 of Fig. 2.

[0159] In the example, the input / output interface 506 may be configured to provide an interface or interfaces to an input device, output device, or one or more input and / or output devices. Examples of an output device include a speaker, a sound card, a video card, a display, a monitor, another output device, or any combination thereof. An input device may allow a user to capture information into the UE 500. Examples of an input device include a touch- sensitive or presence-sensitive display, a camera (e.g., a digital camera, a digital video camera, a web camera, etc.), a microphone, a sensor, a mouse, a trackball, a directional pad, a trackpad, a scroll wheel, a smartcard, and the like. The presence-sensitive display may include a capacitive or resistive touch sensor to sense input from a user. A sensor may be, for instance, an accelerometer, a gyroscope, a tilt sensor, a force sensor, a biometric sensor, etc., or any combination thereof. An output device may use the same type of interface port as an input device. For example, a Universal Serial Bus (USB) port may be used to provide an input device and an output device.

[0160] In some embodiments, the power source 508 is structured as a battery or battery pack. Other types of power sources, such as an external power source (e.g., an electricity outlet), photovoltaic device, or power cell, may be used. The power source 508 may further include power circuitry for delivering power from the power source 508 itself, and / or an external power source, to the various parts of the UE 500 via input circuitry or an interface such as an electrical power cable. Delivering power may be, for example, for charging of the power source 508. Power circuitry may perform any formatting, converting, or other modification to the power from the power source 508 to make the power suitable for the respective components of the UE 500 to which power is supplied.

[0161] The memory 510 may be or be configured to include memory such as random access memory (RAM), read-only memory (ROM), programmable ROM (PROM), erasable PROM (EPROM), electrically EPROM (EEPROM), magnetic disks, optical disks, hard disks, removable cartridges, flash drives, and so forth. In one example, the memory 510 includes one or more application programs 514, such as an operating system, web browser application, awidget, gadget engine, or other application, and corresponding data 516. The memory 510 may store, for use by the UE 500, any of a variety of various operating systems or combinations of operating systems.

[0162] The memory 510 may be configured to include a number of physical drive units, such as redundant array of independent disks (RAID), flash memory, USB flash drive, external hard disk drive, thumb drive, pen drive, key drive, high-density digital versatile disc (HD- DVD) optical disc drive, internal hard disk drive, Blu-Ray optical disc drive, holographic digital data storage (HDDS) optical disc drive, external mini-dual in-line memory module (DIMM), synchronous dynamic random access memory (SDRAM), external micro-DIMM SDRAM, smartcard memory such as tamper resistant module in the form of a universal integrated circuit card (UICC) including one or more subscriber identity modules (SIMs), such as a USIM and / or ISIM, other memory, or any combination thereof. The UICC may for example be an embedded UICC (eUICC), integrated UICC (iUICC) or a removable UICC commonly known as ‘SIM card.’ The memory 510 may allow the UE 500 to access instructions, application programs and the like, stored on transitory or non-transitory memory media, to off-load data, or to upload data. An article of manufacture, such as one utilizing a communication system may be tangibly embodied as or in the memory 510, which may be or comprise a device-readable storage medium.

[0163] The processing circuitry 502 may be configured to communicate with an access network or other network using the communication interface 512. The communication interface 512 may comprise one or more communication subsystems and may include or be communicatively coupled to an antenna 522. The communication interface 512 may include one or more transceivers used to communicate, such as by communicating with one or more remote transceivers of another device capable of wireless communication (e.g., another UE or a network node in an access network). Each transceiver may include a transmitter 518 and / or a receiver 520 appropriate to provide network communications (e.g., optical, electrical, frequency allocations, and so forth). Moreover, the transmitter 518 and receiver 520 may be coupled to one or more antennas (e.g., antenna 522) and may share circuit components, software or firmware, or alternatively be implemented separately.

[0164] In the illustrated embodiment, communication functions of the communication interface 512 may include cellular communication, Wi-Fi communication, LPWAN communication, data communication, voice communication, multimedia communication, short-range communications such as Bluetooth, near-field communication, location-based communication such as the use of the global positioning system (GPS) to determine a location,another like communication function, or any combination thereof. Communications may be implemented in according to one or more communication protocols and / or standards, such as IEEE 802.11, Code Division Multiplexing Access (CDMA), Wideband Code Division Multiple Access (WCDMA), GSM, LTE, NR, UMTS, WiMax, Ethernet, transmission control protocol / intemet protocol (TCP / IP), synchronous optical networking (SONET), Asynchronous Transfer Mode (ATM), QUIC, Hypertext Transfer Protocol (HTTP), and so forth.

[0165] Regardless of the type of sensor, a UE may provide an output of data captured by its sensors, through its communication interface 512, via a wireless connection to a network node. Data captured by sensors of a UE can be communicated through a wireless connection to a network node via another UE. The output may be periodic (e.g., once every 15 minutes if it reports the sensed temperature), random (e.g., to even out the load from reporting from several sensors), in response to a triggering event (e.g., when moisture is detected an alert is sent), in response to a request (e.g., a user initiated request), or a continuous stream (e.g., a live video feed of a patient).

[0166] As another example, a UE comprises an actuator, a motor, or a switch, related to a communication interface configured to receive wireless input from a network node via a wireless connection. In response to the received wireless input the states of the actuator, the motor, or the switch may change. For example, the UE may comprise a motor that adjusts the control surfaces or rotors of a drone in flight according to the received input or to a robotic arm performing a medical procedure according to the received input.

[0167] A UE, when in the form of an loT device, may be a device for use in one or more application domains, these domains comprising, but not limited to, city wearable technology, extended industrial application and healthcare. Non-limiting examples of such an loT device are a device which is or which is embedded in: a connected refrigerator or freezer, a TV, a connected lighting device, an electricity meter, a robot vacuum cleaner, a voice controlled smart speaker, a head-mounted display for Augmented Reality (AR) or Virtual Reality (VR), a wearable for tactile augmentation or sensory enhancement, a water sprinkler, an animal- or item-tracking device, a sensor for monitoring a plant or animal, an industrial robot, an Unmanned Aerial Vehicle (UAV), and any kind of medical device, like a heart rate monitor or a remote controlled surgical robot. A UE in the form of an loT device comprises circuitry and / or software in dependence of the intended application of the loT device in addition to other components as described in relation to the UE 500 shown in Fig. 5.

[0168] As yet another specific example, in an loT scenario, a UE may represent a machine or other device that performs monitoring and / or measurements, and transmits the results ofsuch monitoring and / or measurements to another UE and / or a network node. The UE may in this case be an M2M device, which may in a 3GPP context be referred to as an MTC device. As one particular example, the UE may implement the 3 GPP NB-IoT standard. In other scenarios, a UE may represent a vehicle, such as a car, a bus, a truck, a ship and an airplane, or other equipment that is capable of monitoring and / or reporting on its operational status or other functions associated with its operation.

[0169] In practice, any number of UEs may be used together with respect to a single use case. For example, a first UE might be or be integrated in a drone and provide the drone’s speed information (obtained through a speed sensor) to a second UE that is a remote controller operating the drone. When the user makes changes from the remote controller, the first UE may adjust the throttle on the drone (e.g. by controlling an actuator) to increase or decrease the drone’s speed. The first and / or the second UE can also include more than one of the functionalities described above. For example, a UE might comprise the sensor and the actuator, and handle communication of data for both the speed sensor and the actuators.

[0170] Fig. 6 shows a network node 600 in accordance with some embodiments. As used herein, network node refers to equipment capable, configured, arranged and / or operable to communicate directly or indirectly with a UE and / or with other network nodes or equipment, in a telecommunication network. Examples of network nodes include, but are not limited to, access points (APs) (e.g., radio access points), base stations (BSs) (e.g., radio base stations, Node Bs (NBs), evolved NBs (eNBs) and NRNBs (gNBs)), O-RAN nodes or components of an O-RAN node (e.g., O-RU, O-DU, O-CU).

[0171] Base stations may be categorized based on the amount of coverage they provide (or, stated differently, their transmit power level) and so, depending on the provided amount of coverage, may be referred to as femto base stations, pico base stations, micro base stations, or macro base stations. A base station may be a relay node or a relay donor node controlling a relay. A network node may also include one or more (or all) parts of a distributed radio base station such as centralized digital units, distributed units (e.g., in an O-RAN access node) and / or remote radio units (RRUs), sometimes referred to as Remote Radio Heads (RRHs). Such remote radio units may or may not be integrated with an antenna as an antenna integrated radio. Parts of a distributed radio base station may also be referred to as nodes in a distributed antenna system (DAS).

[0172] Other examples of network nodes include multiple transmission point (multi-TRP) 5G access nodes, multi-standard radio (MSR) equipment such as MSR BSs, network controllers such as radio network controllers (RNCs) or base station controllers (BSCs), basetransceiver stations (BTSs), transmission points, transmission nodes, multi-cell / multicast coordination entities (MCEs), Operation and Maintenance (O&M) nodes, Operations Support System (OSS) nodes, Self-Organizing Network (SON) nodes, positioning nodes (e.g., Evolved Serving Mobile Location Centers (E-SMLCs)), and / or Minimization of Drive Tests (MDTs).

[0173] The network node 600 includes a processing circuitry 602, a memory 604, a communication interface 606, and a power source 608. The network node 600 may be composed of multiple physically separate components (e.g., a NB component and a RNC component, or a BTS component and a BSC component, etc.), which may each have their own respective components. In certain scenarios in which the network node 600 comprises multiple separate components (e.g., BTS and BSC components), one or more of the separate components may be shared among several network nodes. For example, a single RNC may control multiple NBs. In such a scenario, each unique NB and RNC pair, may in some instances be considered a single separate network node. In some embodiments, the network node 600 may be configured to support multiple radio access technologies (RATs). In such embodiments, some components may be duplicated (e.g., separate memory 604 for different RATs) and some components may be reused (e.g., a same antenna 610 may be shared by different RATs). The network node 600 may also include multiple sets of the various illustrated components for different wireless technologies integrated into network node 600, for example GSM, WCDMA, LTE, NR, WiFi, Zigbee, Z-wave, LoRaWAN, Radio Frequency Identification (RFID) or Bluetooth wireless technologies. These wireless technologies may be integrated into the same or different chip or set of chips and other components within network node 600.

[0174] The processing circuitry 602 may comprise a combination of one or more of a microprocessor, controller, microcontroller, central processing unit, digital signal processor, application-specific integrated circuit, field programmable gate array, or any other suitable computing device, resource, or combination of hardware, software and / or encoded logic operable to provide, either alone or in conjunction with other network node 600 components, such as the memory 604, to provide network node 600 functionality.

[0175] In some embodiments, the processing circuitry 602 includes a system on a chip (SOC). In some embodiments, the processing circuitry 602 includes one or more of radio frequency (RF) transceiver circuitry 612 and baseband processing circuitry 614. In some embodiments, the RF transceiver circuitry 612 and the baseband processing circuitry 614 may be on separate chips (or sets of chips), boards, or units, such as radio units and digital units. In alternative embodiments, part or all of RF transceiver circuitry 612 and baseband processingcircuitry 614 may be on the same chip or set of chips, boards, or units. Further, the processing circuitry 602 is configured to perform any steps of method 200 of Fig. 2.

[0176] The memory 604 may comprise any form of volatile or non-volatile computer- readable memory including, without limitation, persistent storage, solid-state memory, remotely mounted memory, magnetic media, optical media, random access memory (RAM), ROM, mass storage media (for example, a hard disk), removable storage media (for example, a flash drive, a Compact Disk (CD) or a Digital Video Disk (DVD)), and / or any other volatile or non-volatile, non-transitory device-readable and / or computer-executable memory devices that store information, data, and / or instructions that may be used by the processing circuitry 602. The memory 604 may store any suitable instructions, data, or information, including a computer program, software, an application including one or more of logic, rules, code, tables, and / or other instructions capable of being executed by the processing circuitry 602 and utilized by the network node 600. The memory 604 may be used to store any calculations made by the processing circuitry 602 and / or any data received via the communication interface 606. In some embodiments, the processing circuitry 602 and memory 604 is integrated.

[0177] The communication interface 606 is used in wired or wireless communication of signaling and / or data between a network node, access network, and / or UE. As illustrated, the communication interface 606 comprises port(s) / terminal(s) 616 to send and receive data, for example to and from a network over a wired connection. The communication interface 606 also includes radio front-end circuitry 618 that may be coupled to, or in certain embodiments a part of, the antenna 610. Radio front-end circuitry 618 comprises filters 620 and amplifiers 622. The radio front-end circuitry 618 may be connected to an antenna 610 and processing circuitry 602. The radio front-end circuitry may be configured to condition signals communicated between antenna 610 and processing circuitry 602. The radio front-end circuitry 618 may receive digital data that is to be sent out to other network nodes or UEs via a wireless connection. The radio front-end circuitry 618 may convert the digital data into a radio signal having the appropriate channel and bandwidth parameters using a combination of filters 620 and / or amplifiers 622. The radio signal may then be transmitted via the antenna 610. Similarly, when receiving data, the antenna 610 may collect radio signals which are then converted into digital data by the radio front-end circuitry 618. The digital data may be passed to the processing circuitry 602. In other embodiments, the communication interface may comprise different components and / or different combinations of components.

[0178] In certain alternative embodiments, the network node 600 does not include separate radio front-end circuitry 618, instead, the processing circuitry 602 includes radio front-endcircuitry and is connected to the antenna 610. Similarly, in some embodiments, all or some of the RF transceiver circuitry 612 is part of the communication interface 606. In still other embodiments, the communication interface 606 includes one or more ports or terminals 616, the radio front-end circuitry 618, and the RF transceiver circuitry 612, as part of a radio unit (not shown), and the communication interface 606 communicates with the baseband processing circuitry 614, which is part of a digital unit (not shown).

[0179] The antenna 610 may include one or more antennas, or antenna arrays, configured to send and / or receive wireless signals. The antenna 610 may be coupled to the radio front-end circuitry 618 and may be any type of antenna capable of transmitting and receiving data and / or signals wirelessly. In certain embodiments, the antenna 610 is separate from the network node 600 and connectable to the network node 600 through an interface or port.

[0180] The antenna 610, communication interface 606, and / or the processing circuitry 602 may be configured to perform any receiving operations and / or certain obtaining operations described herein as being performed by the network node. Any information, data and / or signals may be received from a UE, another network node and / or any other network equipment. Similarly, the antenna 610, the communication interface 606, and / or the processing circuitry 602 may be configured to perform any transmitting operations described herein as being performed by the network node. Any information, data and / or signals may be transmitted to a UE, another network node and / or any other network equipment.

[0181] The power source 608 provides power to the various components of network node 600 in a form suitable for the respective components (e.g., at a voltage and current level needed for each respective component). The power source 608 may further comprise, or be coupled to, power management circuitry to supply the components of the network node 600 with power for performing the functionality described herein. For example, the network node 600 may be connectable to an external power source (e.g., the power grid, an electricity outlet) via an input circuitry or interface such as an electrical cable, whereby the external power source supplies power to power circuitry of the power source 608. As a further example, the power source 608 may comprise a source of power in the form of a battery or battery pack which is connected to, or integrated in, power circuitry. The battery may provide backup power should the external power source fail.

[0182] Embodiments of the network node 600 may include additional components beyond those shown in Fig. 6 for providing certain aspects of the network node’s functionality, including any of the functionality described herein and / or any functionality necessary to support the subject matter described herein. For example, the network node 600 may includeuser interface equipment to allow input of information into the network node 600 and to allow output of information from the network node 600. This may allow a user to perform diagnostic, maintenance, repair, and other administrative functions for the network node 600.

[0183] Fig. 7 is a block diagram illustrating a virtualization environment 700 in which functions implemented by some embodiments may be virtualized. In the present context, virtualizing means creating virtual versions of apparatuses or devices which may include virtualizing hardware platforms, storage devices and networking resources. As used herein, virtualization can be applied to any device described herein, or components thereof, and relates to an implementation in which at least a portion of the functionality is implemented as one or more virtual components. Some or all of the functions described herein may be implemented as virtual components executed by one or more virtual machines (VMs) implemented in one or more virtual environments 700 hosted by one or more of hardware nodes, such as a hardware computing device that operates as a network node, UE, core network node, or host. Further, in embodiments in which the virtual node does not require radio connectivity (e.g., a core network node or host), then the node may be entirely virtualized. In some embodiments, the virtualization environment 700 includes components defined by the O-RAN Alliance, such as an O-Cloud environment orchestrated by a Service Management and Orchestration Framework via an O-2 interface.

[0184] Applications 702 (which may alternatively be called software instances, virtual appliances, network functions, virtual nodes, virtual network functions, etc.) are run in the virtualization environment Q400 to implement some of the features, functions, and / or benefits of some of the embodiments disclosed herein.

[0185] Hardware 704 includes processing circuitry, memory that stores software and / or instructions executable by hardware processing circuitry, and / or other hardware devices as described herein, such as a network interface, input / output interface, and so forth. Software may be executed by the processing circuitry to instantiate one or more virtualization layers 706 (also referred to as hypervisors or virtual machine monitors (VMMs)), provide VMs 708a and 708b (one or more of which may be generally referred to as VMs 708), and / or perform any of the functions, features and / or benefits described in relation with some embodiments described herein. The virtualization layer 706 may present a virtual operating platform that appears like networking hardware to the VMs 708.

[0186] The VMs 708 comprise virtual processing, virtual memory, virtual networking or interface and virtual storage, and may be run by a corresponding virtualization layer 706. Different embodiments of the instance of a virtual appliance 702 may be implemented on oneor more of VMs 708, and the implementations may be made in different ways. Virtualization of the hardware is in some contexts referred to as network function virtualization (NFV). NFV may be used to consolidate many network equipment types onto industry standard high volume server hardware, physical switches, and physical storage, which can be located in data centers, and customer premise equipment.

[0187] In the context of NFV, a VM 708 may be a software implementation of a physical machine that runs programs as if they were executing on a physical, non- virtualized machine. Each of the VMs 708, and that part of hardware 704 that executes that VM, be it hardware dedicated to that VM and / or hardware shared by that VM with others of the VMs, forms separate virtual network elements. Still in the context of NFV, a virtual network function is responsible for handling specific network functions that run in one or more VMs 708 on top of the hardware 704 and corresponds to the application 702.

[0188] Hardware 704 may be implemented in a standalone network node with generic or specific components. Hardware 704 may implement some functions via virtualization. Alternatively, hardware 704 may be part of a larger cluster of hardware (e.g. such as in a data center or CPE) where many hardware nodes work together and are managed via management and orchestration 710, which, among others, oversees lifecycle management of applications 702. In some embodiments, hardware 704 is coupled to one or more radio units that each include one or more transmitters and one or more receivers that may be coupled to one or more antennas. Radio units may communicate directly with other hardware nodes via one or more appropriate network interfaces and may be used in combination with the virtual components to provide a virtual node with radio capabilities, such as a radio access node or a base station. In some embodiments, some signaling can be provided with the use of a control system 712 which may alternatively be used for communication between hardware nodes and radio units.

[0189] Some examples of the teachings of the disclosure are given in the 3GPP TSG RAN WG4 Meeting #108 as follows:Proposal 3: If receiver diversity is in use, the reported wideband normalized correlation amplitude (WNCA) is required to be lower than or equal to the WNCA of the individual receiver branch that has the highest WNCA; and higher than or equal to the WNCA of the individual receiver branch that has the lowest WNCA. Communicate this to RANI in a reply LS to the LS in Rl-2306137.

[0190] Although the computing devices described herein (e.g., UEs, network nodes, hosts) may include the illustrated combination of hardware components, other embodiments may comprise computing devices with different combinations of components. It is to be understoodthat these computing devices may comprise any suitable combination of hardware and / or software needed to perform the tasks, features, functions and methods disclosed herein. Determining, calculating, obtaining or similar operations described herein may be performed by processing circuitry, which may process information by, for example, converting the obtained information into other information, comparing the obtained information or converted information to information stored in the network node, and / or performing one or more operations based on the obtained information or converted information, and as a result of said processing making a determination. Moreover, while components are depicted as single boxes located within a larger box, or nested within multiple boxes, in practice, computing devices may comprise multiple different physical components that make up a single illustrated component, and functionality may be partitioned between separate components. For example, a communication interface may be configured to include any of the components described herein, and / or the functionality of the components may be partitioned between the processing circuitry and the communication interface. In another example, non-computationally intensive functions of any of such components may be implemented in software or firmware and computationally intensive functions may be implemented in hardware.

[0191] In certain embodiments, some or all of the functionality described herein may be provided by processing circuitry executing instructions stored on in memory, which in certain embodiments may be a computer program product in the form of a non-transitory computer- readable storage medium. In alternative embodiments, some or all of the functionality may be provided by the processing circuitry without executing instructions stored on a separate or discrete device-readable storage medium, such as in a hard-wired manner. In any of those particular embodiments, whether executing instructions stored on a non-transitory computer- readable storage medium or not, the processing circuitry can be configured to perform the described functionality. The benefits provided by such functionality are not limited to the processing circuitry alone or to other components of the computing device, but are enjoyed by the computing device as a whole, and / or by end users and a wireless network generally.

[0192] Those skilled in the art will recognize improvements and modifications to the embodiments of the present disclosure. All such improvements and modifications are considered within the scope of the concepts disclosed herein.

Claims

CLAIMS1. A method performed by a user equipment (UE), the method comprising: measuring a normalized channel correlation amplitude (NCA) with receiver diversity, which comprises multiple receiver branches; and reporting, to a network node, an indication of the measured NCA, wherein the reporting is based on the measured NCA, the measured NCA being not lower than a minimum and not higher than a maximum measured values across the multiple receiver branches.

2. The method of claim 1, further comprising determining, based on one or more criteria, a set of receivers for measuring the NCA with the receiver diversity and wherein measuring the NCA is based on the determined set of receivers.

3. The method of claim 2, wherein the one or more criteria comprise using receivers which are used for receiving a certain type of reference signals or using receivers which are used for performing a certain type of measurements.

4. The method of claim 3, wherein the reference signals are Tracking Reference Signals (TRS).

5. The method of any one of claims 1 to 4, wherein the NCA comprises time domain channel properties (TDCP).

6. A method performed by a network node, the method comprising: configuring a UE to measure a normalized channel correlation amplitude (NCA) with receiver diversity, which comprises multiple branches; and receiving an indication of a measured NCA, wherein the measured NCA is not lower than a minimum and not higher than a maximum measured values across the multiple receiver branches.

7. The method of claim 6, further comprising using the received indication of the measured NCA for performing one or more operational tasks.

8. The method of claim 6 or 7, wherein configuring the UE comprises sending a signalingmessage to the UE to measure the NCA, wherein the message comprises configuration parameters.

9. The method of claim 8, wherein the configuration parameters comprise symbol pairs to use for the measurement of the NCA.

10. The method of any one of claims 6 to 9, wherein configuring the UE comprises configuring the UE with one or more parameters, which comprise one or more of thresholds and reference values, for determining receivers to be used for measuring the NCA with receiver diversity.

11. The method of any one of claims 6 to 10, wherein receiving the indication of the measured NCA is based on a configuration of a reporting mechanism.

12. A User Equipment (UE) comprising processing circuitry and a network interface connected thereto, the processing circuitry configured to perform the method of any one of claims 1 to 5.

13. A network node comprising processing circuitry and a network interface connected thereto, the processing circuitry configured to perform the method of any one of claims 6 to 11.

14. A computer program product comprising a computer readable memory storing computer executable instructions thereon that when executed by a computer perform any one of the methods of any one of claims 1 to 11.

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