REPORTING PHASE DIFFERENCES BETWEEN TRPs

Abstract

Systems and methods for reporting phase differences between Transmission and Reception Points (TRPs) are provided. In some embodiments, a method performed by a User Equipment (UE) includes: receiving a Channel State Information (CSI) report configuration from a network node for reporting phase differences associated to a plurality of Downlink Reference Signals (DL-RSs); performing phase measurement based on the plurality of DL-RSs; determining phase differences associated with the plurality of DL-RSs; and reporting, to the network node, the determined phase differences. In this way, reciprocity based Coherent Joint Transmission (CJT) can be enabled without costly cross-TRP calibration to remove the inter-TRP phase differences. Additionally, providing the network with information about the inter-TRP phase differences makes it possible to compensate the phase differences, resulting in more efficient CJT.

Description

REPORTING PHASE DIFFERENCES BETWEEN TRPs RELATED APPLICATIONS

[0001] This application claims the benefit of provisional patent application serial number 63 / 555,307, filed February 19, 2024, the disclosure of which is hereby incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present disclosure relates generally to reporting phase differences. BACKGROUND

[0003] Similar to LTE, the 5thgeneration (5G) mobile systems or NR (New Radio) uses OFDM (Orthogonal Frequency Division Multiplexing) in the downlink (i.e. from a network node, gNB, eNB, or base station, to a user equipment or UE). In the uplink (i.e., from UE to gNB), both OFDM and DFT-spread OFDM (DFT-S-OFDM) are supported. The basic NR physical resource can thus be seen as a time-frequency grid as illustrated in Figure 1, where a resource block (RB) in a 14-symbol slot is shown. An RB corresponds to 12 contiguous subcarriers in the frequency domain. RBs are numbered in the frequency domain, starting with 0 from one end of the system bandwidth. Each resource element corresponds to one OFDM subcarrier during one OFDM symbol interval.

[0004] Different subcarrier spacings are supported in NR. The supported subcarrier spacings(also referred to as numerologies) are given by ∆^ = (15 × 2^) ^^^ where ^ is a non-negativeinteger and can be one of {0, 1, 2, 3, 4}. ∆^ = 15^^^ (e.g., ^ = 0) is the basic (or reference)subcarrier spacing that is also used in LTE. ^ is also referred to as the numerology.

[0005] In the time domain, downlink and uplink transmissions in NR are organized into equally sized subframes of 1ms each. A subframe is further divided into multiple slots of equal ^ duration. The slot length is dependent on the subcarrier spacing or numerology and is given by^^ms. Each slot consists of 14 OFDM symbols for normal Cyclic Prefix (CP).

[0006] Data scheduling in NR can be in slot basis. Downlink (DL) transmissions can be dynamically scheduled, i.e., in each slot the gNB transmits downlink control information (DCI) about which UE data is to be transmitted to and which resource blocks in the current downlink slot the data is transmitted on. The control information is carried on Physical Control Channel (PDCCH) and data is carried on Physical Downlink Shared Channel (PDSCH). A UE first detectsand decodes PDCCH and if a PDCCH is decoded successfully, it then decodes the corresponding PDSCH based on the decoded control information in the PDCCH.

[0007] Uplink (UL) data transmission can also be dynamically scheduled using PDCCH. Similar to downlink, a UE first decodes uplink grants in PDCCH and then transmits data over the Physical Uplink Shared Channel (PUSCH) based the decoded control information in the uplink grant such as modulation order, coding rate, uplink resource allocation, and etc.

[0008] Coherent Joint PDSCH transmission from Multiple TRPs

[0009] In 3GPP NR (new Radio) Rel-18, Channel State Information (CSI) feedback or reporting for Coherent Joint PDSCH Transmission (CJT) over multiple transmission and reception points (TRPs) was introduced. In CJT, the signal of each MIMO layer of a PDSCH (physical downlink shared channel) is transmitted jointly from multiple TRPs to a UE (User equipment) in a same time and frequency resource. Before the transmission, the signal at each TRP is phase adjusted such that the phase adjusted signals from the multiple TRPs are phase aligned when reaching the UE and thus, are coherently combined. The power of the combined signal should be larger than that when received from a single TRP. This would improve the signal quality received at the UE.

[0010] Figure 2 illustrates an example of coherent joint PDSCH transmission over two TRPs.An example is shown in Figure 2, where a PDSCH with ^ layers, i.e., ^ = ^^ ^^, ^^, … , ^^^ , istransmitted from two TRPs after being precoded by a precoding matrix ^^at TRP#1 and a precoding matrix ^^at TRP#2. Each element of the precoding matrices is a complex coefficient. The precoding helps to achieve coherent (or constructive) combining of signals from the two TRPs at the UE for each layer.

[0011] The precoders ^^and ^^can be reported by the UE as part of a CSI report for CJT, which was introduced in Rel-18, or determined by the NW based on uplink (UL) reference signals transmitted from the UE in TDD systems assuming channel reciprocity. The latter is referred to as reciprocity based CJT. An CJT CSI typically comprises a rank (i.e., number of layers) indicator (RI), a channel quality indicator (CQI), and a precoding matrix indicator (PMI). ^^and ^^would be indicated by the PMI.

[0012] In NR Rel-18 CJT CSI, ideal synchronization between TRPs is assumed. In other words, the symbol / slot / frame timing and carrier frequency are exactly the same in different TRPs.

[0013] In practice, some level of timing and carrier frequency offsets do exist across different TRPs. The issue has been recognized and will be addressed in NR Rel-19 via UE measurementand reporting of time and frequency differences between TRPs. The reporting will be a standalone report, meaning that it will not be combined with legacy CSI reports.

[0014] CSI report in NR

[0015] In NR, for CSI reporting purpose, a UE can be configured with one or more channel (CSI) report configurations each comprising one or more Non-zero Power (NZP) CSI reference signal (CSI-RS) resources for channel measurements and a codebook used for CSI feedback. In addition to PMI and RI, the feedback typically also comprises one (for rank<=4) or two (for rank>4) channel quality indicators (CQIs).

[0016] PMI and CQI feedback can be either wideband or per subband, where a wideband can be a whole bandwidth part (BWP) configured while a subband is defined as a number of contiguous physical resource blocks (PRBs) within a BWP.

[0017] A CSI report configuration is done by RRC (radio resource control) signaling via a RRC parameter CSI-ReportConfig defined in 3gpp TS38.331. The report can be periodic or semi- persistent on PUCCH (physical uplink control channel) in a cell in which the CSI-ReportConfig is configured, or semi-persistent or aperiodic sent on PUSCH (physical uplink shared channel) triggered by a DCI (downlink control information) format received in the cell in which the CSI- ReportConfig is configured.

[0018] A NZP CSI-RS resource can have up to 32 CSI-RS antenna ports. In NR CSI reporting, one or more NZP CSI-RS resource sets can be configured and associated to a CSI report configuration for channel measurements. A NZP CSI-RS resource set contains one or more NZP CSI-RS resources.

[0019] NZP CSI-RS

[0020] CSI-RS is used for downlink channel measurement between a transmit antenna and a receive antenna. CSI-RS is configured by CSI-RS resources and can be transmitted on one or multiple antenna ports, also referred to as CSI-RS antenna ports or CSI-RS ports. Each CSI-RS port is transmitted in certain time and frequency resources configured in a corresponding CSI-RS resource. The supported number of antenna ports in NR are {1, 2, 4, 8, 12, 16, 24, 32}. By measuring the received CSI-RS, a UE can estimate the channel that the CSI-RS is traversing, including the radio propagation channel and antenna gains. The CSI-RS for the above purpose is also referred to as NZP CSI-RS.

[0021] Figure 3 illustrates an example of a RE allocation for a 12-port CSI-RS resource in NR. Figure 3 shows an example of one CSI-RS RE allocation for 12 CSI-RS ports in a CSI-RSresource with frequency density one, i.e., average one RE per RB per CSI-RS port. CSI-RS is transmitted in every RB in a configured CSI-RS bandwidth, only CSI-RS in one RB is shown Figure 3.

[0022] In 6G, terms other than NZP CSI-RS might be used. For example, a new downlink reference signal or downlink synchronization signal might be introduced in 6G which can be used instead of NZP CSI-RS. The 6G downlink reference signals and / or downlink synchronization signals might be aperiodically, semi-persistently or periodically transmitted. In the following the terms “DL-RS”, “NZP CSI-RS” and “NZP CSI-RS resource set” may be used interchangeably. Also, although the term TRP is used in this disclosure, the term TRP may not be captured in 3GPP specifications. Instead, a TRP can be represented by any one of ‘NZP CSI-RS resource set’, ‘NZP CSI-RS resource’, ‘TRS resource set’, and / or ‘TRS resource’, or in general Downlink Reference Signal (DL-RS). Improved systems and methods are needed. SUMMARY

[0023] Systems and methods for reporting phase differences between Transmission and Reception Points (TRPs) are provided. In some embodiments, a method performed by a User Equipment (UE) includes: receiving a Channel State Information (CSI) report configuration from a network node for reporting phase differences associated to a plurality of Downlink Reference Signals (DL-RSs); performing phase measurement based on the plurality of DL-RSs; determining phase differences associated with the plurality of DL-RSs; and reporting, to the network node, the determined phase differences. In this way, reciprocity based Coherent Joint Transmission (CJT) can be enabled without costly cross-TRP calibration to remove the inter-TRP phase differences. Additionally, providing the network with information about the inter-TRP phase differences makes it possible to compensate the phase differences, resulting in more efficient CJT.

[0024] In some embodiments, a method performed by a network node includes: transmitting a CSI report configuration to a UE; and receiving a report, from the UE, comprising phase differences associated with different DL-RSs.

[0025] In some embodiments, determining the phase differences also includes: determining a phase difference for each TRP of a plurality of TRPs based on the channel measurement, where the phase difference is with respect to a reference TRP.

[0026] In some embodiments, the method also includes determining the reference TRP; and reporting the determined reference TRP to the network node. In some embodiments, reporting the determined phase differences further comprises: the determined reference TRP.

[0027] In some embodiments, the reported determined phase differences includes: N-1 phase differences each associated to one of N Non-zero Power (NZP) CSI reference signal (CSI-RS) resources; where the phase differences are with respect to a reference TRP, for which the phase difference is zero and is not reported.

[0028] In some embodiments, the reported determined phase differences includes quantized points where the number of quantized points is configurable by higher layer signaling.

[0029] In some embodiments, the method also includes one or more of: receiving a configuration of multiple NZP CSI-RS resources, each associated to a TRP, for channel measurement; receiving a precoded and time / frequency compensated CSI-RS at each TRP in the associated CSI-RS resource; receiving TRS; estimating and / or reporting time and / or frequency difference between each TRP and a reference TRP based on the received TRS; transmitting UL RS; receiving precoded and time / frequency difference compensated CSI-RS; and receiving PDSCH.

[0030] In some embodiments, for each TRP, precoding is applied to the associated CSI-RS at each RB with a precoding matrix determined for the RB and the TRP.

[0031] In some embodiments, the phase differences between the multiple TRPs can berepresent by a complex vector ^ = ^1, ^ !"# , … , ^ !"$%^ ,where &^*^*∙^ ^*(+ ^)' ∈ {0,+,+, ... ,+ } isthe phase difference ( / ' − / ^)

[0032] In some embodiments, the CSI-RS transmitted at each frequency or RB from each TRP is precoded according to a respective precoder determined at the frequency or RB.

[0033] In some embodiments, the time delay and frequency differences between TRP can be either pre-compensated at the NW for the CSI-RS before being transmitted or at the UE.

[0034] In some embodiments, RI and / or CQI are also reported based on the channel measurements. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawing figures incorporated in and forming a part of this specification illustrate several aspects of the disclosure, and together with the description serve to explain the principles of the disclosure.

[0036] Figure 1 illustrates the basic New Radio (NR) physical resource can thus be seen as a time-frequency grid where a resource block (RB) in a 14-symbol slot is shown;

[0037] Figure 2 illustrates an example of coherent joint PDSCH transmission over two TRPs;

[0038] Figure 3 illustrates an example of a RE allocation for a 12-port CSI-RS resource in NR;

[0039] Figure 4 illustrates an example where there are N TRPs, according to some embodiments of the current disclosure;

[0040] Figure 5 illustrates the phase variation over time associated with two TRPs which are shown by two lines, where the two TRPs are associated with the two CSI-RSs (i.e., CSI-RSs #1 and #2 are transmitted from two TRPs), according to some embodiments of the current disclosure;

[0041] Figure 6 illustrates an example when there are time delay differences among the TRPs observed at the UE due to either timing offsets or propagation delay differences, the phase differences between TRPs can change over frequency, according to some embodiments of the current disclosure;

[0042] Figure 7 illustrates an approach with NW side time and frequency pre-compensation for CSI-RS where the method is related to the boxes with solid lines, according to some embodiments of the current disclosure;

[0043] Figure 8 illustrates a method of operating a UE, according to some embodiments of the current disclosure;

[0044] Figure 9 shows an example of a communication system in accordance with some embodiments;

[0045] Figure 10 shows a UE in accordance with some embodiments;

[0046] Figure 11 shows a network node in accordance with some embodiments;

[0047] Figure 12 is a block diagram of a host, which may be an embodiment of the host of Figure 9, in accordance with various aspects described herein;

[0048] Figure 13 is a block diagram illustrating a virtualization environment in which functions implemented by some embodiments may be virtualized; and

[0049] Figure 14 shows a communication diagram of a host communicating via a network node with a UE over a partially wireless connection in accordance with some embodiments. DETAILED DESCRIPTION

[0050] The embodiments set forth below represent information to enable those skilled in the art to practice the embodiments and illustrate the best mode of practicing the embodiments. Upon reading the following description in light of the accompanying drawing figures, those skilled in the art will understand the concepts of the disclosure and will recognize applications of these concepts not particularly addressed herein. It should be understood that these concepts and applications fall within the scope of the disclosure.

[0051] 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.

[0052] There currently exist certain challenges. In reciprocity-based downlink (DL) transmission, the receive and transmit circuitries at each TRP is typically calibrated such that the same gain and phase are maintained across different receive and transmit circuitries associated to different antennas. The absolute phase at each TRP is unknown and is not needed for single TRP transmission. For CJT based on CJT CSI feedback, the unknown phase at each TRP is not a problem because it is considered in the reported PMI.

[0053] The unknow phase at each TRP is, however, a problem for reciprocity based CJT because coherent transmission is not possible without knowing the phase difference between the TRPs. One possible solution is to request the UE to feedback the phase differences between TRPs, such a method is described in patent application PCT / IB2024 / 050353 filed on January 13, 2024, in which ideal time and frequency synchronization between TRPs is assumed. The contents of this application are hereby incorporated herein in its entirety. When there are time delay differences and / or carrier frequency differences / offsets between TRPs, how to estimate and feedback the inter-TRP phase differences is a problem.

[0054] Certain aspects of the disclosure and their embodiments may provide solutions to these or other challenges. A method is proposed for measuring and reporting phase difference(s) between TRPs, the method comprising one or more of the following: Configuring, by the network, a UE with multiple NZP CSI-RS resources, each associated to a TRP, for channel measurement. Transmitting, by the network, a precoded and time / frequency compensated CSI-RS at each TRP in the associated CSI-RS resource. Performing, by the UE, channel measurement for each TRP based on the associated CSI-RS resource. Determining, by the UE, a phase difference for each TRP based on the channel measurement, where the phase difference is with respect to a reference TRP. Reporting, by the UE, to the network the phase differences.

[0055] Some embodiments disclosed herein include reporting the inter-TRP phase differences based on one or more of the following procedures: • Determining, by the NW, a precoding matrix at each RB (or a group of subcarriers) and at each of multiple TRPs based on an uplink reference signal. • Transmitting, by the NW, a precoded CSI-RS from each of the multiple TRPs, where different CSI-RSs are transmitted from different TRPs.o For each TRP, precoding is applied to the associated CSI-RS at each RB with a precoding matrix determined for the RB and the TRP, i.e., frequency dependent precoding. o Optionally, the NW also applies a time and frequency compensation to the precoded CSI-RS at each TRP before being transmitted • Performing, by the UE, channel measurements based on the precoded CSI-RS associated to each TRP. o Optionally, if configured / indicated by the NW, the UE applies a TRP specific time and frequency compensation to the channel measurement associated to each TRP • Determining a phase difference for each of the multiple TRPs or a subset of the multiple TRPs with respect to a reference TRP based on the channel measurements or pre-compensated channel measurements, o the reference TRP is either pre-determined or selected by the UE. o Optionally, If configured / indicated by the NW, a RI and / or CQI(s) can be further determined based on the channel measurements and the phase differences. • Reporting, by the UE, the phase differences for the TRPs except the reference TRP in a CSI report o Optionally, the report can further comprise an identifier of the UE selected reference TRP. o Optionally, the report can further include a RI and / or CQI(s) • Applying phase pre-compensation to a PDSCH at each TRP based on the report before the PDSCH being transmitted. o The phase pre-compensation is in addition to time and frequency pre- compensation to the PDSCH at each TRP o The PDSCH is further precoded by the same precoding matrix used to precode the CSI-RS at each TRP

[0056] Certain embodiments may provide one or more of the following technical advantages. The method enables reciprocity based CJT without costly cross TRP calibration to remove the inter-TRP phase differences. Particularly, providing the NW with information about the inter- TRP phase differences makes it possible to compensate the phase differences, resulting in efficient CJT.

[0057] Note. In 6G, other terms than NZP CSI-RS might be used. For example, a new downlink reference signal or downlink synchronization signal might be introduced in 6G which can be used instead of NZP CSI-RS. The 6G downlink reference signals and / or downlink synchronization signals might be aperiodically, semi-persistently or periodically transmitted. In the following the terms “DL-RS”, “NZP CSI-RS” and “NZP CSI-RS resource set” may be used interchangeably. Also, although the term TRP is used in this disclosure, the term TRP may not be captured in 3GPP specifications. Instead, a TRP can be represented by any one of ‘NZP CSI-RS resource set’, ‘NZP CSI-RS resource’, ‘TRS resource set’, and / or ‘TRS resource’, or in general downlink reference signal (DL-RS).

[0058] In reciprocity based CJT transmission to a UE, a rank and a precoding matrix associated to each of multiple TRPs are determined by the network based on uplink reference signals (RS) such as SRS (sounding reference signal) or DMRS (demodulation reference signal) transmitted from the UE. To achieve coherent combining of signals from the multiple TRPs at the UE, the phase differences between different TRPs and a reference TRP are needed in order to pre- compensate the phase differences before joint data transmission over the TRPs.

[0059] The phase differences can be due to RF (radio frequency) circuitry associated to antennas in each TRP and also the channels between the TRPs and the UE. For ideal channel reciprocity between DL and UL, the part of phase difference due to the channels should have been considered in the precoding matrices and compensated for after the precoding matrices are applied. In this case, the phase differences to be determined are mainly due to RF circuitry.

[0060] To obtain the phase differences, multiple DL reference signals (DL RSs), one over each TRP, can be precoded and transmitted from the multiple TRPs. The UE measures the DL channels associated to each of the multiple TRPs based on the corresponding DL RS and estimates the phase difference between each of the multiple TRPs and a reference TRP. The estimated phase differences are then reported back to the network. The phase differences are compensated for at the network before joint data transmission over the TRPs with the respective precoders.

[0061] An example is shown in Figure 4, where there are N TRPs. There is a phase, / ' (3 =1, ... , 4), associated to each TRP. For estimation of the phase, NZP CSI-RS in a NZP CSI-RSresource are precoded and transmitted from each of the N TRPs. There can be one or more CSI- RS ports in each of the NZP CSI-RS resources, each CSI-RS port is associated to a layer. Theequivalent DL channel for the i-th TRP at a resource block is given by 56 ' = ^!785'9' =^:'(1), … , :'(^)^ ∈ ;<=>×^, where 9 <? ∈ ; @>×^ is the precodingis the equivalentchannel associated to the k-th layer, 4^Ais the number transmit antennas at each TRP, 4BAis thenumber receive antennas at the UE, ^ is the number of layers determined for CJT by the NW based on UL channel measurements.

[0062] In a possible, and most probable case, the phase differences are determined with respect to a reference TRP, where the reference TRP is either indicated by the NW, understood via pre-defined rules or selected by the UE and fed back to the network.

[0063] In one embodiment, the reference TRP is the first TRP, and the phase differencesbetween the multiple TRPs can be represent by a complex vector ^ = ^1, ^ !"# , … , ^ !"$%^ ,where & ^*∙' ∈ {0,^* +, ^+, ... , ^*(+ ^)+} is the phase difference andinteger, e.g., P =4 and M=16. Then, ^ (or N indicescontained in ^) is / are reported to the network. At the networkside, a phase adjustment is applied for each of the precoding matrices {9^, … , 9<} , i.e.,{9^, ^ !"#9^, … , ^ !"$9<}, which are used for coherent joint data is nofrequency offset between TRPs. ^ can be determined by maximizing the following utility function by the UE. C(^) = ∑^HI^ |^FG(^)FG(^) ^|^ (eq. 1)where G(^) = ^:^(^), … :<(^)^

[0064] In some embodiment, NZP CSI-RS resource with a single CSI-RS port can be used for the purpose. In that case, a precoder for a single layer is used to precode the NZP CSI-RS at eachTRP, i.e., one column of 9? is used. The utility function then becomes C(^) =|^FG(^)FG(^) )^|, where the CSI-RS port is associated to the k-th layer.

[0065] When there are carrier frequency differences among the TRPs, the phase differences between TRPs can change over time. An example is shown in Figure 5. In the figure, the phase variation over time associated with two TRPs are shown by the two lines, where the two TRPs are associated with the two CSI-RSs (i.e., CSI-RSs #1 and #2 are transmitted from two TRPs). The following actions are illustrated in the figure: At time t1, the UE receives CSI-RSs #1 and measures the phase / ^(J1); at time t1’, the UE receives CSI-RS #2 and measures the phase / ^(J1). Thephase difference is then computed / calculated by ∆ / = / ^(J1′) − / ^(J1) . At time t2, the UEreports the phase difference ∆ / = / ^(J1′) − / ^(J1) after it is quantized to some finite set ofvalues. At time t3, the UE receives joint PDSCH transmission (i.e., CJT PDSCH) transmission from the two TRPs.

[0066] Due to frequency offset difference (^^ − ^^) between two TRPs, the phase difference,∆ / (J1) = / ^(J1) − / ^(J1), at time t1 would be different from the phase difference, ∆ / (J3) = / ^(J3) − / ^(J3), at t3 when the joint data transmission occurs. If the network knows (^^ − ^^),∆ / (J3) can be calculated as ∆ / (J3) = ∆ / (J1) + 2N(^^ − ^^) for phase adjustment at the twoTRPs for coherent joint data transmission at t3. However, if CSI-RS from the two TRPs are transmitted at different times as illustrated in Figure 5,difference measured at the UEwould be / ^(J1′)− / ^(J1), which is different than ∆ / (J1) if (^^ − ^^) ≠ 0. As a result, thecalculated ∆ / based on / ^(J1′)− / ^(J1)would be incorrect.

[0067] embodiment, to ensure correct phase adjustment for coherent joint data transmission, the NZP CSI-RS resources are received by the UE in the same OFDM symbol(s).

[0068] In another embodiment, if the CSI-RSs from different TRPs are transmitted in different time instances, the phase difference / change between the time instances due to carrier frequency differences / offsets are pre-compensated at the NW by applying phase adjustments to the CSI-RS before being transmitted. This assumes that the NW knows the frequency differences, either estimated based on uplink reference signals or reported by the UE, prior to the CSI-RS transmission.

[0069] In another embodiment, a maximum time offset (or time gap) between any two NZP CSI-RS resources to be used for measuring the phases and computing the phase differences may be predefined in 3GPP specifications. For instance, a maximum time offset of ^ symbols may bepredefined in 3GPP specifications where ^ is an integer number (e.g., 3, 4, 5, 9, etc.).Alternatively, the maximum time offset may be defined in slots. In another embodiment, the maximum time offset may depend on UE capability which is reported by the UE to the network (NW). In a further embodiment, the maximum time offset is configured from the network to the UE. The motivation for introducing the maximum time offset is to limit the phase variation over time when the NZP CSI-RS resources are received in different times by putting an upper bound on the maximum time separation between the NZP CSI-RS resources (i.e., by limiting the maximum time separation, we limit the phase variation over time).In a further embodiment, the phase difference / change between the time instances due to carrier frequency differences / offsets are pre-compensated (i.e., removed from the channel measurements based on the CSI-RS) by the UE before estimating the phase difference between TRPs provided that the UE has estimated the frequency differences based on DL reference signals prior to the CSI-RS reception. The procedure can be summarized as follows: The UE receives a first DL RS and a second DL RS to be used for frequency difference measurement between the first DL RS and the second DL RS. The UEestimates the frequency difference (^^ − ^^) between the first and second DL RSs based onmeasurements performed on the two DL RSs. The UE receives the precoded NZP CSI-RSs #1 and #2 at times t1 and t1’, respectively. The UE measures the channel based on NZP CSI-RSs #1and #2 and computes the phase difference ∆ / = / ^(J1P) − / ^(J1). The UE compensates thephase variation between times t1 and t1’ using the estimated phase difference ∆ / ′ = ∆ / +2N(^ − ^ )(J P^ ^ 1 − J1). The UE feeds back the compensated phase difference ∆ / ′ to the network.

[0070] The pre-compensation above also applies to the case when each offrom each in multiple time instances such as OFDM symbols, where the phase changes across the OFDM symbols are pre-compensated or removed from the channel measurement associated to each TRP before estimating the phase difference between TRPs.

[0071] Using the example in Figure 5, after the pre-compensation, the phase differencebetween the two TRPs should be the same, i.e., / ^(J1′)− / ^(J1) = 0 for J1′ ≠ J1.

[0072] When there are time delay differences among the TRPs observed at the UE due to either timing offsets or propagation delay differences, the phase differences between TRPs can change over frequency as illustrated in Figure 6, where Q^and Q^are the delays associated to thefirst and second TRPs, respectively. In this case, if (Q^ − Q^) ≠ 0 , the phase estimation isfrequency dependent and the reported phase differences areif the NW knows at which frequency or RB the phase differences are measured.

[0073] Hence in some embodiment, the CSI-RS transmitted at each frequency or RB from each TRP is precoded according to a respective precoder determined at the frequency or RB. This is referred to as frequency dependent precoding for CSI-RS. The precoder is assumed to contain a phase adjustment to compensate for the effect of the delay such that the phase differences observed at the UE are the same over frequency.

[0074] In another embodiment, the phase difference / change between different frequency instances (e.g., subcarrier or RBs) due to time delay differences between TRPs are pre- compensated at the NW by applying a phase adjustment to the CSI-RS at each subcarrier frequency or RB at each TRP before the CSI-RS being transmitted. This assumes that the NW knows the time delay differences, either estimated based on uplink reference signals or reported by the UE, prior to the CSI-RS transmission. In this case, the precoding for the CSI-RS at each TRP can be wideband (i.e., the same precoding matrix is applied at different sub-carrier frequencies or RBs).

[0075] In a further embodiment, the phase change between different frequency instances (e.g., subcarrier or RBs) due to time delay differences between TRPs are pre-compensated (i.e., removed from the channel measurements based on the CSI-RS) by the UE before estimating the phase difference between TRPs. This assumes that the UE has estimated the time delay differences based on DL reference signals prior to the CSI-RS reception.

[0076] The pre-compensation above also applies to the case when the CSI-RSs from each TRP are transmitted in multiple frequency instances such as subcarriers or RBs, where the phasechanges across the frequencies are pre-compensated or removed from the channel measurement associated to each TRP before estimating the phase difference between TRPs.

[0077] Using the example in Figure 6, after the pre-compensation, the phase difference acrossfrequencies between the two TRPs should be the same, i.e., ∆ / (^2) = ∆ / (^1) for ^1 ≠ ^2.

[0078] With delay pre-compensation of the CSI-RS, either at the NW or the UE, ^ can be estimated by averaging the utility function in Equation 1 overover which the CSI-RS are transmitted and channels are measured.

[0079] In a general embodiment, the time delay and frequency differences between TRP can be either pre-compensated at the NW for the CSI-RS before being transmitted or at the UE. The UE needs to know whether the pre-compensation for the CSI-RS is done by the NW or need to be done by the UE. This can be indicated explicitly in the report configuration or implicitly by linked to some other configuration, e.g., when ‘X’ is configured, then the pre-compensation is to be done at the UE.

[0080] The approach with NW side time and frequency pre-compensation for CSI-RS is illustrated in Figure 7, where the method is related to the boxes with solid lines.

[0081] In another embodiment, in addition to reporting phase differences, RI and / or CQI may also be reported based on the channel measurements. If indicated, CQI may be reported either for wideband or per subband.

[0082] Figure 8 illustrates a method of operating a UE, according to some embodiments of the current disclosure. In some embodiments, the method comprises the following steps at the UE. Step 1: Receiving (step 800) a CSI report configuration comprising a NZP CSI-RS resource setwith 4 (4 ≥ 2) NZP CSI-RS resources for channel measurement and a report quantity indicatingphase difference feedback. Step 2. Performing (step 802) channel measurement based on the N NZP CSI-RS resources. Step 3. Determining (step 804), based on the channel measurement, a phase difference associated to each of the N NZP CSI-RS resources. Step 4. Reporting (step 806) to the network the determined phase differences associated to the N NZP CSI-RS resources.

[0083] In Step 1, each of the N NZP CSI-RS resources comprises a same number of CSI-RS antenna ports, where each CSI-RS port is associated to a MIMO layer and is precoded at each TRP with a precoder associated to the layer and the TRP. Different precoders are used at different RBs. The precoders are determined by the NW based on UL reference signals. The N NZP CSI-RS resources can be periodic, semi-persistent, or aperiodic and are in the same OFDM symbols of a slot.

[0084] The CSI report configuration can further comprise an indication indicating whether RI and / or CQI are also to be reported in addition to phase differences. In case CQI is reported, theCSI report configuration can further comprise a frequency domain granularity indication indicating whether the CQI is wideband or subband.

[0085] In one embodiment, one or more of the following values are possible values that can be configured in the report configuration: phaseDifference-r19: this corresponds to reporting phase difference(s) only in the report; phaseDifference-r19-RI-CQI: this corresponds to reporting phase difference(s), rank and CQI in the report; phaseDifference-r19-RI: this corresponds to reporting phase difference(s) and rank in the report; phaseDifference-r19-CQI: this corresponds to reporting phase difference(s) and CQI in the report.

[0086] In one embodiment, one or more of the following values are possible values that can be configured for a new parameter (e.g., reportQuantitySubset-19) introduced the CSI- AperiodicTriggerStateList information element defined in 3GPP TS 38.331 V18.0.0: phaseDifference-19 (similar definition as above); phaseDifference-r19-RI-CQI (similar definition as above); phaseDifference-r19-RI (similar definition as above); and phaseDifference-r19-CQI (similar definition as above).

[0087] In one embodiment, the number of quantized points for the reported phase difference,1 = 22 is fixed according to the specification. Alternatively, the number of quantized points isconfigurable by higher layer signaling by the network. In some embodiments, the higher layer signaling configures the total number, M. In some embodiments, the higher layer signaling configures the length of bitfield, P.

[0088] In Step 2, the UE measures the frequency domain channel associated to each of the N NZP CSI-RS resources. The channel comprises multiple channel matrices one at each frequency instance, e.g., RB.

[0089] In Step 3, the phase differences { &' , 3 = 2, .. , 4} are estimated based on the channelmeasurements and a utility function e.g., (eq.1). Prior to estimating the phase differences, the UE can be indicated to perform time and frequency pre-compensation on the channel estimation associated to each TRP.

[0090] In Step 4, the report comprises N-1 phase differences each associated to one of the N NZP CSI-RS resources. The phase differences are with respect to a reference TRP, for which the phase difference is zero and is not reported. The reference TRP can be a first TRP configured in the NZP CSI-RS resource set. Alternatively, the reference TRP can be reported by the UE in the same report.

[0091] In another embodiment, in addition to reporting phase differences, RI and / or CQI may also be reported based on the channel measurements. If indicated, CQI may be reported either for wideband or per subband.

[0092] In some embodiment, UE receives from the NW a trigger for an aperiodic CSI report to report the phase difference between the multiple TRPs. The NW may trigger a subset of report quantities such as: phaseDifferences, RI, and CQI; phaseDifferences only; phaseDifferences plus CQI.

[0093] In some embodiment, the NW triggers a CSI report that CSI-RSs are configured in the same OFDM symbol based on an earlier received UE CSI reporting on frequency offset measurement and frequency offset compensation applied by the NW.

[0094] In some embodiment, the NW triggers a CSI report that includes information on averaging the utility function over different frequencies, based on an earlier received UE CSI reporting on delay difference measurement and delay difference compensation applied by the NW.

[0095] In some embodiment, UE transmits an aperiodic CSI reporting on phase difference using PUSCH by receiving a DCI format 0_1 or DCI format 0_2 which triggers the aperiodic CSI trigger state configured to report at least phase difference.

[0096] In some embodiment, UE is configured by the higher layer to transmit periodic CSI reporting to report at least phase difference on the PUCCH.

[0097] The method comprises the following steps at the network. Step 1: measuring uplink channel based on an uplink reference signal at each of a plurality of TRPs. Step 2: computing a rank and a precoding matrix per RB (or a group of subcarriers) based on the uplink channel measurement at each of the plurality of TRPs according to a codebook of precoders. Step 3: Applying the precoding matrices together with time and frequency compensation at each TRP to a CSI-RS associated to the TRP. Step 4: transmitting the precoded and time / frequency compensated CSI-RS at each of plurality of TRPs at the same OFDM symbols. Step 5: Configuring and requesting the UE to measure and report a phase difference for each of the plurality of TRPs based on the CSI-RS with respect to a reference TRP. Step 6: Receiving the report and applying a phase adjustment to a precoded PDSCH at each of the plurality of TRPs based on the received phase difference for the TRP. Step 7: Transmitting the precoded and phase adjusted PDSCH over the plurality of TRPs.

[0098] Figure 9 shows an example of a communication system 900 in accordance with some embodiments.

[0099] In the example, the communication system 900 includes a telecommunication network 902 that includes an access network 904, such as a Radio Access Network (RAN), and a core network 906, which includes one or more core network nodes 908. The access network 904 includes one or more access network nodes, such as network nodes 910A and 910B (one or more of which may be generally referred to as network nodes 910), or any other similar Third GenerationPartnership Project (3GPP) access nodes or non-3GPP Access Points (APs). 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 902 includes one or more Open-RAN (ORAN) network nodes. An ORAN network node is a node in the telecommunication network 902 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 902, including one or more network nodes 910 and / or core network nodes 908.

[0100] 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 A1, F1, W1, E1, E2, X2, Xn interface, an open fronthaul user plane interface, or an open fronthaul management plane interface. Moreover, an ORAN access node 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 O-2 interface defined by the O-RAN Alliance or comparable technologies. The network nodes 910 facilitate direct or indirect connection of User Equipment (UE), such as by connecting UEs 912A, 912B, 912C, and 912D (one or more of which may be generally referred to as UEs 912) to the core network 906 over one or more wireless connections.

[0101] 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 900 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 / orsignals whether via wired or wireless connections. The communication system 900 may include and / or interface with any type of communication, telecommunication, data, cellular, radio network, and / or other similar type of system.

[0102] The UEs 912 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 910 and other communication devices. Similarly, the network nodes 910 are arranged, capable, configured, and / or operable to communicate directly or indirectly with the UEs 912 and / or with other network nodes or equipment in the telecommunication network 902 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 902.

[0103] In the depicted example, the core network 906 connects the network nodes 910 to one or more hosts, such as host 916. 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 906 includes one more core network nodes (e.g., core network node 908) 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 908. 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).

[0104] The host 916 may be under the ownership or control of a service provider other than an operator or provider of the access network 904 and / or the telecommunication network 902, and may be operated by the service provider or on behalf of the service provider. The host 916 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.

[0105] As a whole, the communication system 900 of Figure 9 enables connectivity between the UEs, network nodes, and hosts. In that sense, the communication system 900 may be configured to operate according to predefined rules or procedures, such as specific standards thatinclude, but are not limited to: Global System for Mobile Communications (GSM); Universal Mobile Telecommunications System (UMTS); Long Term Evolution (LTE), and / or other suitable Second, Third, Fourth, or Fifth Generation (2G, 3G, 4G, or 5G) standards, or any applicable future generation standard (e.g., Sixth Generation (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.

[0106] In some examples, the telecommunication network 902 is a cellular network that implements 3GPP standardized features. Accordingly, the telecommunication network 902 may support network slicing to provide different logical networks to different devices that are connected to the telecommunication network 902. For example, the telecommunication network 902 may provide Ultra Reliable Low Latency Communication (URLLC) services to some UEs, while providing enhanced Mobile Broadband (eMBB) services to other UEs, and / or massive Machine Type Communication (mMTC) / massive Internet of Things (IoT) services to yet further UEs.

[0107] In some examples, the UEs 912 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 904 on a predetermined schedule, when triggered by an internal or external event, or in response to requests from the access network 904. Additionally, a UE may be configured for operating in single- or multi-Radio Access Technology (RAT) or multi-standard mode. For example, a UE may operate with any one or combination of WiFi, New Radio (NR), and LTE, i.e. being configured for Multi-Radio Dual Connectivity (MR-DC), such as Evolved UMTS Terrestrial RAN (E-UTRAN) NR - Dual Connectivity (EN-DC).

[0108] In the example, a hub 914 communicates with the access network 904 to facilitate indirect communication between one or more UEs (e.g., UE 912C and / or 912D) and network nodes (e.g., network node 910B). In some examples, the hub 914 may be a controller, router, content source and analytics, or any of the other communication devices described herein regarding UEs. For example, the hub 914 may be a broadband router enabling access to the core network 906 for the UEs. As another example, the hub 914 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 910, or by executable code, script, process, or other instructions in the hub 914. As another example, the hub 914 may be a data collector that acts as temporary storage for UE dataand, in some embodiments, may perform analysis or other processing of the data. As another example, the hub 914 may be a content source. For example, for a UE that is a Virtual Reality (VR) headset, display, loudspeaker or other media delivery device, the hub 914 may retrieve VR assets, video, audio, or other media or data related to sensory information via a network node, which the hub 914 then provides to the UE either directly, after performing local processing, and / or after adding additional local content. In still another example, the hub 914 acts as a proxy server or orchestrator for the UEs, in particular if one or more of the UEs are low energy IoT devices.

[0109] The hub 914 may have a constant / persistent or intermittent connection to the network node 910B. The hub 914 may also allow for a different communication scheme and / or schedule between the hub 914 and UEs (e.g., UE 912C and / or 912D), and between the hub 914 and the core network 906. In other examples, the hub 914 is connected to the core network 906 and / or one or more UEs via a wired connection. Moreover, the hub 914 may be configured to connect to a Machine-to-Machine (M2M) service provider over the access network 904 and / or to another UE over a direct connection. In some scenarios, UEs may establish a wireless connection with the network nodes 910 while still connected via the hub 914 via a wired or wireless connection. In some embodiments, the hub 914 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 910B. In other embodiments, the hub 914 may be a non-dedicated hub – that is, a device which is capable of operating to route communications between the UEs and the network node 910B, but which is additionally capable of operating as a communication start and / or end point for certain data channels.

[0110] Figure 10 shows a UE 1000 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 Internet Protocol (VoIP) phone, wireless local loop phone, desktop computer, Personal Digital Assistant (PDA), wireless camera, 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 Narrowband Internet of Things (NB-IoT) UE, a Machine Type Communication (MTC) UE, and / or an enhanced MTC (eMTC) UE.

[0111] A UE may support Device-to-Device (D2D) communication, for example by implementing a 3GPP standard for sidelink communication, Dedicated Short-RangeCommunication (DSRC), Vehicle-to-Vehicle (V2V), Vehicle-to-Infrastructure (V2I), or Vehicle- to-Everything (V2X). In other examples, a UE may not necessarily have a user in the sense of a human user who owns and / or operates the relevant device. Instead, a UE may represent a device that is intended for sale to, or operation by, a human user but which may not, or 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).

[0112] The UE 1000 includes processing circuitry 1002 that is operatively coupled via a bus 1004 to an input / output interface 1006, a power source 1008, memory 1010, a communication interface 1012, and / or any other component, or any combination thereof. Certain UEs may utilize all or a subset of the components shown in Figure 10. 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.

[0113] The processing circuitry 1002 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 1010. The processing circuitry 1002 may be implemented as one or more hardware-implemented state machines (e.g., in discrete logic, Field Programmable Gate Arrays (FPGAs), Application Specific Integrated Circuits (ASICs), etc.); programmable logic together with appropriate firmware; one or more stored computer programs, general purpose processors, such as a microprocessor or Digital Signal Processor (DSP), together with appropriate software; or any combination of the above. For example, the processing circuitry 1002 may include multiple Central Processing Units (CPUs).

[0114] In the example, the input / output interface 1006 may be configured to provide an interface or interfaces to an input device, output device, or one or more input and / or output devices. Examples of an output device include a speaker, a sound card, a video card, a display, a monitor, a printer, an actuator, an emitter, a smartcard, another output device, or any combination thereof. An input device may allow a user to capture information into the UE 1000. Examples of an input device include a touch-sensitive or presence-sensitive display, a camera (e.g., a digital camera, a digital video camera, a web camera, etc.), a microphone, a sensor, a mouse, a trackball, a directional pad, a trackpad, a scroll wheel, a smartcard, and the like. The presence-sensitive display may include a capacitive or resistive touch sensor to sense input from a user. A sensor may be, for instance, an accelerometer, a gyroscope, a tilt sensor, a force sensor, a magnetometer,an optical sensor, a proximity sensor, a biometric sensor, etc., or any combination thereof. An output device may use the same type of interface port as an input device. For example, a Universal Serial Bus (USB) port may be used to provide an input device and an output device.

[0115] In some embodiments, the power source 1008 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 1008 may further include power circuitry for delivering power from the power source 1008 itself, and / or an external power source, to the various parts of the UE 1000 via input circuitry or an interface such as an electrical power cable. Delivering power may be, for example, for charging of the power source 1008. Power circuitry may perform any formatting, converting, or other modification to the power from the power source 1008 to make the power suitable for the respective components of the UE 1000 to which power is supplied.

[0116] The memory 1010 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 1010 includes one or more application programs 1014, such as an operating system, web browser application, a widget, gadget engine, or other application, and corresponding data 1016. The memory 1010 may store, for use by the UE 1000, any of a variety of various operating systems or combinations of operating systems.

[0117] The memory 1010 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 RAM (SDRAM), external micro-DIMM SDRAM, smartcard memory such as a tamper resistant module in the form of a Universal Integrated Circuit Card (UICC) including one or more Subscriber Identity Modules (SIMs), such as a Universal SIM (USIM) and / or Internet Protocol Multimedia Services Identity Module (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 a ‘SIM card.’ The memory 1010 may allow the UE 1000 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 utilizinga communication system, may be tangibly embodied as or in the memory 1010, which may be or comprise a device-readable storage medium.

[0118] The processing circuitry 1002 may be configured to communicate with an access network or other network using the communication interface 1012. The communication interface 1012 may comprise one or more communication subsystems and may include or be communicatively coupled to an antenna 1022. The communication interface 1012 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 1018 and / or a receiver 1020 appropriate to provide network communications (e.g., optical, electrical, frequency allocations, and so forth). Moreover, the transmitter 1018 and receiver 1020 may be coupled to one or more antennas (e.g., the antenna 1022) and may share circuit components, software, or firmware, or alternatively be implemented separately.

[0119] In the illustrated embodiment, communication functions of the communication interface 1012 may include cellular communication, WiFi communication, LPWAN communication, data communication, voice communication, multimedia communication, short- range communications such as Bluetooth, NFC, 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 according to one or more communication protocols and / or standards, such as IEEE 802.11, Code Division Multiplexing Access (CDMA), Wideband CDMA (WCDMA), GSM, LTE, NR, UMTS, WiMax, Ethernet, Transmission Control Protocol / Internet Protocol (TCP / IP), Synchronous Optical Networking (SONET), Asynchronous Transfer Mode (ATM), Quick User Datagram Protocol Internet Connection (QUIC), Hypertext Transfer Protocol (HTTP), and so forth.

[0120] Regardless of the type of sensor, a UE may provide an output of data captured by its sensors, through its communication interface 1012, 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).

[0121] 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 theswitch 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.

[0122] A UE, when in the form of an IoT 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 IoT device are a device which is or which is embedded in: a connected refrigerator or freezer, a television, a connected lighting device, an electricity meter, a robot vacuum cleaner, a voice controlled smart speaker, a home security camera, a motion detector, a thermostat, a smoke detector, a door / window sensor, a flood / moisture sensor, an electrical door lock, a connected doorbell, an air conditioning system like a heat pump, an autonomous vehicle, a surveillance system, a weather monitoring device, a vehicle parking monitoring device, an electric vehicle charging station, a smart watch, a fitness tracker, a head-mounted display for Augmented Reality (AR) or 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 IoT device comprises circuitry and / or software in dependence of the intended application of the IoT device in addition to other components as described in relation to the UE 1000 shown in Figure 10.

[0123] As yet another specific example, in an IoT scenario, a UE may represent a machine or other device that performs monitoring and / or measurements and transmits the results of such monitoring and / or measurements to another UE and / or a network node. The UE may in this case be an M2M device, which may in a 3GPP context be referred to as an MTC device. As one particular example, the UE may implement the 3GPP NB-IoT standard. In other scenarios, a UE may represent a vehicle, such as a car, a bus, a truck, a ship, an airplane, or other equipment that is capable of monitoring and / or reporting on its operational status or other functions associated with its operation.

[0124] 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 describedabove. For example, a UE might comprise the sensor and the actuator and handle communication of data for both the speed sensor and the actuators.

[0125] Figure 11 shows a network node 1100 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, APs (e.g., radio APs), Base Stations (BSs) (e.g., radio BSs, Node Bs, evolved Node Bs (eNBs), NR Node Bs (gNBs)), and O-RAN nodes or components of an O-RAN node (e.g., O-RU, O-DU, O-CU).

[0126] 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 RRUs 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).

[0127] 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 BS Controllers (BSCs), Base Transceiver Stations (BTSs), transmission points, transmission nodes, Multi-Cell / Multicast Coordination Entities (MCEs), Operation and Maintenance (O&M) nodes, Operations Support System (OSS) nodes, Self-Organizing Network (SON) nodes, positioning nodes (e.g., Evolved Serving Mobile Location Centers (E-SMLCs)), and / or Minimization of Drive Tests (MDTs).

[0128] The network node 1100 includes processing circuitry 1102, memory 1104, a communication interface 1106, and a power source 1108. The network node 1100 may be composed of multiple physically separate components (e.g., a NodeB component and an 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 1100 comprises multiple separate components (e.g., BTS and BSC components), one or more of the separate components may be shared among several network nodes. For example, a single RNC may control multiple NodeBs. In such a scenario, each unique NodeB and RNC pair may in some instances be considered a single separate network node. In some embodiments, the network node 1100 may be configured to support multiple RATs. In such embodiments, some components may be duplicated(e.g., separate memory 1104 for different RATs) and some components may be reused (e.g., a same antenna 1110 may be shared by different RATs). The network node 1100 may also include multiple sets of the various illustrated components for different wireless technologies integrated into network node 1100, for example GSM, WCDMA, LTE, NR, WiFi, Zigbee, Z-wave, Long Range Wide Area Network (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 the network node 1100.

[0129] The processing circuitry 1102 may comprise a combination of one or more of a microprocessor, controller, microcontroller, CPU, DSP, ASIC, FPGA, 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 1100 components, such as the memory 1104, to provide network node 1100 functionality.

[0130] In some embodiments, the processing circuitry 1102 includes a System on a Chip (SOC). In some embodiments, the processing circuitry 1102 includes one or more of Radio Frequency (RF) transceiver circuitry 1112 and baseband processing circuitry 1114. In some embodiments, the RF transceiver circuitry 1112 and the baseband processing circuitry 1114 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 the RF transceiver circuitry 1112 and the baseband processing circuitry 1114 may be on the same chip or set of chips, boards, or units.

[0131] The memory 1104 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, 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 1102. The memory 1104 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 1102 and utilized by the network node 1100. The memory 1104 may be used to store any calculations made by the processing circuitry 1102 and / or any data received via the communication interface 1106. In some embodiments, the processing circuitry 1102 and the memory 1104 are integrated.

[0132] The communication interface 1106 is used in wired or wireless communication of signaling and / or data between a network node, access network, and / or UE. As illustrated, thecommunication interface 1106 comprises port(s) / terminal(s) 1116 to send and receive data, for example to and from a network over a wired connection. The communication interface 1106 also includes radio front-end circuitry 1118 that may be coupled to, or in certain embodiments a part of, the antenna 1110. The radio front-end circuitry 1118 comprises filters 1120 and amplifiers 1122. The radio front-end circuitry 1118 may be connected to the antenna 1110 and the processing circuitry 1102. The radio front-end circuitry 1118 may be configured to condition signals communicated between the antenna 1110 and the processing circuitry 1102. The radio front-end circuitry 1118 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 1118 may convert the digital data into a radio signal having the appropriate channel and bandwidth parameters using a combination of the filters 1120 and / or the amplifiers 1122. The radio signal may then be transmitted via the antenna 1110. Similarly, when receiving data, the antenna 1110 may collect radio signals which are then converted into digital data by the radio front-end circuitry 1118. The digital data may be passed to the processing circuitry 1102. In other embodiments, the communication interface 1106 may comprise different components and / or different combinations of components.

[0133] In certain alternative embodiments, the network node 1100 does not include separate radio front-end circuitry 1118; instead, the processing circuitry 1102 includes radio front-end circuitry and is connected to the antenna 1110. Similarly, in some embodiments, all or some of the RF transceiver circuitry 1112 is part of the communication interface 1106. In still other embodiments, the communication interface 1106 includes the one or more ports or terminals 1116, the radio front-end circuitry 1118, and the RF transceiver circuitry 1112 as part of a radio unit (not shown), and the communication interface 1106 communicates with the baseband processing circuitry 1114, which is part of a digital unit (not shown).

[0134] The antenna 1110 may include one or more antennas, or antenna arrays, configured to send and / or receive wireless signals. The antenna 1110 may be coupled to the radio front-end circuitry 1118 and may be any type of antenna capable of transmitting and receiving data and / or signals wirelessly. In certain embodiments, the antenna 1110 is separate from the network node 1100 and connectable to the network node 1100 through an interface or port.

[0135] The antenna 1110, the communication interface 1106, and / or the processing circuitry 1102 may be configured to perform any receiving operations and / or certain obtaining operations described herein as being performed by the network node 1100. Any information, data, and / or signals may be received from a UE, another network node, and / or any other network equipment. Similarly, the antenna 1110, the communication interface 1106, and / or the processing circuitry 1102 may be configured to perform any transmitting operations described herein as beingperformed by the network node 1100. Any information, data, and / or signals may be transmitted to a UE, another network node, and / or any other network equipment.

[0136] The power source 1108 provides power to the various components of the network node 1100 in a form suitable for the respective components (e.g., at a voltage and current level needed for each respective component). The power source 1108 may further comprise, or be coupled to, power management circuitry to supply the components of the network node 1100 with power for performing the functionality described herein. For example, the network node 1100 may be connectable to an external power source (e.g., the power grid or an electricity outlet) via input circuitry or an interface such as an electrical cable, whereby the external power source supplies power to power circuitry of the power source 1108. As a further example, the power source 1108 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.

[0137] Embodiments of the network node 1100 may include additional components beyond those shown in Figure 11 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 1100 may include user interface equipment to allow input of information into the network node 1100 and to allow output of information from the network node 1100. This may allow a user to perform diagnostic, maintenance, repair, and other administrative functions for the network node 1100.

[0138] Figure 12 is a block diagram of a host 1200, which may be an embodiment of the host 916 of Figure 9, in accordance with various aspects described herein. As used herein, the host 1200 may be or comprise various combinations of hardware and / or software including a standalone server, a blade server, a cloud-implemented server, a distributed server, a virtual machine, container, or processing resources in a server farm. The host 1200 may provide one or more services to one or more UEs.

[0139] The host 1200 includes processing circuitry 1202 that is operatively coupled via a bus 1204 to an input / output interface 1206, a network interface 1208, a power source 1210, and memory 1212. Other components may be included in other embodiments. Features of these components may be substantially similar to those described with respect to the devices of previous figures, such as Figures 10 and 11, such that the descriptions thereof are generally applicable to the corresponding components of the host 1200.

[0140] The memory 1212 may include one or more computer programs including one or more host application programs 1214 and data 1216, which may include user data, e.g. data generatedby a UE for the host 1200 or data generated by the host 1200 for a UE. Embodiments of the host 1200 may utilize only a subset or all of the components shown. The host application programs 1214 may be implemented in a container-based architecture and may provide support for video codecs (e.g., Versatile Video Coding (VVC), High Efficiency Video Coding (HEVC), Advanced Video Coding (AVC), Moving Picture Experts Group (MPEG), VP9) and audio codecs (e.g., Free Lossless Audio Codec (FLAC), Advanced Audio Coding (AAC), MPEG, G.711), including transcoding for multiple different classes, types, or implementations of UEs (e.g., handsets, desktop computers, wearable display systems, and heads-up display systems). The host application programs 1214 may also provide for user authentication and licensing checks and may periodically report health, routes, and content availability to a central node, such as a device in or on the edge of a core network. Accordingly, the host 1200 may select and / or indicate a different host for Over-The-Top (OTT) services for a UE. The host application programs 1214 may support various protocols, such as the HTTP Live Streaming (HLS) protocol, Real-Time Messaging Protocol (RTMP), Real-Time Streaming Protocol (RTSP), Dynamic Adaptive Streaming over HTTP (DASH or MPEG-DASH), etc.

[0141] Figure 13 is a block diagram illustrating a virtualization environment 1300 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 1300 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 1300 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.

[0142] Applications 1302 (which may alternatively be called software instances, virtual appliances, network functions, virtual nodes, virtual network functions, etc.) are run in the virtualization environment 1300 to implement some of the features, functions, and / or benefits of some of the embodiments disclosed herein.

[0143] Hardware 1304 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 1306 (also referred to as hypervisors or VM Monitors (VMMs)), provide VMs 1308A and 1308B (one or more of which may be generally referred to as VMs 1308), and / or perform any of the functions, features, and / or benefits described in relation with some embodiments described herein. The virtualization layer 1306 may present a virtual operating platform that appears like networking hardware to the VMs 1308.

[0144] The VMs 1308 comprise virtual processing, virtual memory, virtual networking, or interface and virtual storage, and may be run by a corresponding virtualization layer 1306. Different embodiments of the instance of a virtual appliance 1302 may be implemented on one or more of the VMs 1308, 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.

[0145] In the context of NFV, a VM 1308 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 1308, and that part of the hardware 1304 that executes that VM, be it hardware dedicated to that VM and / or hardware shared by that VM with others of the VMs 1308, 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 1308 on top of the hardware 1304 and corresponds to the application 1302.

[0146] The hardware 1304 may be implemented in a standalone network node with generic or specific components. The hardware 1304 may implement some functions via virtualization. Alternatively, the hardware 1304 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 1310, which, among others, oversees lifecycle management of the applications 1302. In some embodiments, the hardware 1304 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 RAN or a base station. In some embodiments, somesignaling can be provided with the use of a control system 1312 which may alternatively be used for communication between hardware nodes and radio units.

[0147] Figure 14 shows a communication diagram of a host 1402 communicating via a network node 1404 with a UE 1406 over a partially wireless connection in accordance with some embodiments. Example implementations, in accordance with various embodiments, of the UE (such as the UE 912A of Figure 9 and / or the UE 1000 of Figure 10), the network node (such as the network node 910A of Figure 9 and / or the network node 1100 of Figure 11), and the host (such as the host 916 of Figure 9 and / or the host 1200 of Figure 12) discussed in the preceding paragraphs will now be described with reference to Figure 14.

[0148] Like the host 1200, embodiments of the host 1402 include hardware, such as a communication interface, processing circuitry, and memory. The host 1402 also includes software, which is stored in or is accessible by the host 1402 and executable by the processing circuitry. The software includes a host application that may be operable to provide a service to a remote user, such as the UE 1406 connecting via an OTT connection 1450 extending between the UE 1406 and the host 1402. In providing the service to the remote user, a host application may provide user data which is transmitted using the OTT connection 1450.

[0149] The network node 1404 includes hardware enabling it to communicate with the host 1402 and the UE 1406. The connection 1460 may be direct or pass through a core network (like the core network 906 of Figure 9) and / or one or more other intermediate networks, such as one or more public, private, or hosted networks. For example, an intermediate network may be a backbone network or the Internet.

[0150] The UE 1406 includes hardware and software, which is stored in or accessible by the UE 1406 and executable by the UE’s processing circuitry. The software includes a client application, such as a web browser or operator-specific “app” that may be operable to provide a service to a human or non-human user via the UE 1406 with the support of the host 1402. In the host 1402, an executing host application may communicate with the executing client application via the OTT connection 1450 terminating at the UE 1406 and the host 1402. In providing the service to the user, the UE's client application may receive request data from the host's host application and provide user data in response to the request data. The OTT connection 1450 may transfer both the request data and the user data. The UE's client application may interact with the user to generate the user data that it provides to the host application through the OTT connection 1450.

[0151] The OTT connection 1450 may extend via the connection 1460 between the host 1402 and the network node 1404 and via a wireless connection 1470 between the network node 1404and the UE 1406 to provide the connection between the host 1402 and the UE 1406. The connection 1460 and the wireless connection 1470, over which the OTT connection 1450 may be provided, have been drawn abstractly to illustrate the communication between the host 1402 and the UE 1406 via the network node 1404, without explicit reference to any intermediary devices and the precise routing of messages via these devices.

[0152] As an example of transmitting data via the OTT connection 1450, in step 1408, the host 1402 provides user data, which may be performed by executing a host application. In some embodiments, the user data is associated with a particular human user interacting with the UE 1406. In other embodiments, the user data is associated with a UE 1406 that shares data with the host 1402 without explicit human interaction. In step 1410, the host 1402 initiates a transmission carrying the user data towards the UE 1406. The host 1402 may initiate the transmission responsive to a request transmitted by the UE 1406. The request may be caused by human interaction with the UE 1406 or by operation of the client application executing on the UE 1406. The transmission may pass via the network node 1404 in accordance with the teachings of the embodiments described throughout this disclosure. Accordingly, in step 1412, the network node 1404 transmits to the UE 1406 the user data that was carried in the transmission that the host 1402 initiated, in accordance with the teachings of the embodiments described throughout this disclosure. In step 1414, the UE 1406 receives the user data carried in the transmission, which may be performed by a client application executed on the UE 1406 associated with the host application executed by the host 1402.

[0153] In some examples, the UE 1406 executes a client application which provides user data to the host 1402. The user data may be provided in reaction or response to the data received from the host 1402. Accordingly, in step 1416, the UE 1406 may provide user data, which may be performed by executing the client application. In providing the user data, the client application may further consider user input received from the user via an input / output interface of the UE 1406. Regardless of the specific manner in which the user data was provided, the UE 1406 initiates, in step 1418, transmission of the user data towards the host 1402 via the network node 1404. In step 1420, in accordance with the teachings of the embodiments described throughout this disclosure, the network node 1404 receives user data from the UE 1406 and initiates transmission of the received user data towards the host 1402. In step 1422, the host 1402 receives the user data carried in the transmission initiated by the UE 1406.

[0154] One or more of the various embodiments improve the performance of OTT services provided to the UE 1406 using the OTT connection 1450, in which the wireless connection 1470 forms the last segment. More precisely, the teachings of these embodiments may improve the e.g.,data rate, latency, power consumption, etc. and thereby provide benefits such as e.g., reduced user waiting time, relaxed restriction on file size, improved content resolution, better responsiveness, extended battery lifetime, etc.

[0155] In an example scenario, factory status information may be collected and analyzed by the host 1402. As another example, the host 1402 may process audio and video data which may have been retrieved from a UE for use in creating maps. As another example, the host 1402 may collect and analyze real-time data to assist in controlling vehicle congestion (e.g., controlling traffic lights). As another example, the host 1402 may store surveillance video uploaded by a UE. As another example, the host 1402 may store or control access to media content such as video, audio, VR, or AR which it can broadcast, multicast, or unicast to UEs. As other examples, the host 1402 may be used for energy pricing, remote control of non-time critical electrical load to balance power generation needs, location services, presentation services (such as compiling diagrams etc. from data collected from remote devices), or any other function of collecting, retrieving, storing, analyzing, and / or transmitting data.

[0156] In some examples, a measurement procedure may be provided for the purpose of monitoring data rate, latency, and other factors on which the one or more embodiments improve. There may further be an optional network functionality for reconfiguring the OTT connection 1450 between the host 1402 and the UE 1406 in response to variations in the measurement results. The measurement procedure and / or the network functionality for reconfiguring the OTT connection 1450 may be implemented in software and hardware of the host 1402 and / or the UE 1406. In some embodiments, sensors (not shown) may be deployed in or in association with other devices through which the OTT connection 1450 passes; the sensors may participate in the measurement procedure by supplying values of the monitored quantities exemplified above, or by supplying values of other physical quantities from which software may compute or estimate the monitored quantities. The reconfiguring of the OTT connection 1450 may include message format, retransmission settings, preferred routing, etc.; the reconfiguring need not directly alter the operation of the network node 1404. Such procedures and functionalities may be known and practiced in the art. In certain embodiments, measurements may involve proprietary UE signaling that facilitates measurements of throughput, propagation times, latency, and the like by the host 1402. The measurements may be implemented in that software causes messages to be transmitted, in particular empty or ‘dummy’ messages, using the OTT connection 1450 while monitoring propagation times, errors, etc.

[0157] Although the computing devices described herein (e.g., UEs, network nodes, hosts) may include the illustrated combination of hardware components, other embodiments maycomprise computing devices with different combinations of components. It is to be understood that 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.

[0158] In certain embodiments, some or all of the functionality described herein may be provided by processing circuitry executing instructions stored 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 hardwired 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.

[0159] 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.

[0160] EMBODIMENTS

[0161] Group A Embodiments

[0162] Embodiment 1: A method performed by a user equipment, the method comprising one or more of: reporting inter-TRP phase differences; receiving a configuration of multiple NZP CSI-RS resources, each associated to a TRP, for channel measurement; receiving a precoded and time / frequency compensated CSI-RS at each TRP in the associated CSI-RS resource; performing channel measurement for each TRP based on the associated CSI-RS resource; determining a phase difference for each TRP based on the channel measurement, where the phase difference is with respect to a reference TRP; reporting to the network the phase differences; receiving TRS (e.g., TRP specific, one per TRP); estimating and / or reporting time and / or frequency difference between each TRP and a reference TRP based on the received TRS; transmitting UL RS; receiving precoded and time / frequency difference compensated CSI-RS (e.g., TRP specific, one per TRP); estimating and / or reporting phase difference between each TRP and the reference TRP based on the received CSI-RS; and receiving PDSCH.

[0163] Embodiment 2: The method of any of the previous embodiments wherein: for each TRP, precoding is applied to the associated CSI-RS at each RB with a precoding matrix determined for the RB and the TRP, i.e., frequency dependent precoding.

[0164] Embodiment 3: The method of any of the previous embodiments wherein: the NW also applies a time and frequency compensation to the precoded CSI-RS at each TRP before being transmitted.

[0165] Embodiment 4: The method of any of the previous embodiments wherein: if configured / indicated by the NW, the UE applies a TRP specific time and frequency compensation to the channel measurement associated to each TRP.

[0166] Embodiment 5: The method of any of the previous embodiments wherein: the reference TRP is either pre-determined or selected by the UE.

[0167] Embodiment 6: The method of any of the previous embodiments wherein: if configured / indicated by the NW, a RI and / or CQI(s) can be further determined based on the channel measurements and the phase differences.

[0168] Embodiment 7: The method of any of the previous embodiments wherein: the report further comprises an identifier of the UE selected reference TRP.

[0169] Embodiment 8: The method of any of the previous embodiments wherein: the report further comprises a RI and / or CQI(s).

[0170] Embodiment 9: The method of any of the previous embodiments wherein: the phase pre-compensation is in addition to time and frequency pre-compensation to the PDSCH at each TRP.

[0171] Embodiment 10: The method of any of the previous embodiments wherein: the PDSCH is further precoded by the same precoding matrix used to precode the CSI-RS at each TRP.

[0172] Embodiment 11: The method of any of the previous embodiments wherein: the reference TRP is the first TRP, and the phase differences between the multiple TRPs can berepresent by a complex vector ^ = ^1, ^ !"# , … , ^ !"$%^ ,where &^*^*∙^ ^*(+ ^)' ∈ {0,+,+, ... ,+ }is the phase difference ( / − / ^) between TRP#i and

[0173] Embodiment 12: The method of any of the to ensure correct phase adjustment for coherent joint data transmission, the NZP CSI-RS resources are received by the UE in the same OFDM symbol(s).

[0174] Embodiment 13: The method of any of the previous embodiments wherein: if the CSI- RSs from different TRPs are transmitted in different time instances, the phase difference / change between the time instances due to carrier frequency differences / offsets are pre-compensated at the NW by applying phase adjustments to the CSI-RS before being transmitted.

[0175] Embodiment 14: The method of any of the previous embodiments wherein: a maximum time offset (or time gap) between any two NZP CSI-RS resources to be used for measuring the phases and computing the phase differences is predefined in 3GPP specifications.

[0176] Embodiment 15: The method of any of the previous embodiments wherein: the maximum time offset may depend on UE capability which is reported by the UE to the network (NW).

[0177] Embodiment 16: The method of any of the previous embodiments wherein: the maximum time offset is configured from the network to the UE.

[0178] Embodiment 17: The method of any of the previous embodiments wherein: the phase difference / change between the time instances due to carrier frequency differences / offsets are pre- compensated (i.e., removed from the channel measurements based on the CSI-RS) by the UE before estimating the phase difference between TRPs provided that the UE has estimated the frequency differences based on DL reference signals prior to the CSI-RS reception.

[0179] Embodiment 18: The method of any of the previous embodiments wherein: the CSI- RS transmitted at each frequency or RB from each TRP is precoded according to a respective precoder determined at the frequency or RB.

[0180] Embodiment 19: The method of any of the previous embodiments wherein: the phase difference / change between different frequency instances (e.g., subcarrier or RBs) due to time delay differences between TRPs are pre-compensated at the NW by applying a phase adjustment to the CSI-RS at each subcarrier frequency or RB at each TRP before the CSI-RS being transmitted.

[0181] Embodiment 20: The method of any of the previous embodiments wherein: the phase change between different frequency instances (e.g., subcarrier or RBs) due to time delay differences between TRPs are pre-compensated (i.e., removed from the channel measurements based on the CSI-RS) by the UE before estimating the phase difference between TRPs.

[0182] Embodiment 21: The method of any of the previous embodiments wherein: the time delay and frequency differences between TRP can be either pre-compensated at the NW for the CSI-RS before being transmitted or at the UE.

[0183] Embodiment 22: The method of any of the previous embodiments wherein: RI and / or CQI are also reported based on the channel measurements.

[0184] Embodiment 23: The method of any of the previous embodiments, further comprising: providing user data; and forwarding the user data to a host via the transmission to the network node.

[0185] Group B Embodiments

[0186] Embodiment 24: A method performed by a network node, the method comprising one or more of: receiving a report of inter-TRP phase differences; transmitting a configuration of multiple NZP CSI-RS resources, each associated to a TRP, for channel measurement; transmitting a precoded and time / frequency compensated CSI-RS at each TRP in the associated CSI-RS resource; receiving channel measurement for each TRP based on the associated CSI-RS resource; receiving a phase difference for each TRP based on the channel measurement, where the phase difference is with respect to a reference TRP; receiving from the UE the phase differences; transmitting TRS (e.g., TRP specific, one per TRP); receiving time and / or frequency difference between each TRP and a reference TRP based on the received TRS; receiving UL RS; transmitting precoded and time / frequency difference compensated CSI-RS (e.g., TRP specific, one per TRP); receiving phase difference between each TRP and the reference TRP based on the received CSI- RS; and transmitting PDSCH.

[0187] Embodiment 25: The method of the previous embodiment further including any of the features of the Group A Embodiments or any other embodiments included herein.

[0188] Embodiment 26: The method of any of the previous embodiments, further comprising: obtaining user data; and forwarding the user data to a host or a user equipment.

[0189] Group C Embodiments

[0190] Embodiment 27: A user equipment, comprising: processing circuitry configured to perform any of the steps of any of the Group A embodiments; and power supply circuitry configured to supply power to the processing circuitry.

[0191] Embodiment 28: A network node, the network node comprising: processing circuitry configured to perform any of the steps of any of the Group B embodiments; and power supply circuitry configured to supply power to the processing circuitry.

[0192] Embodiment 29: A user equipment (UE), the UE comprising: an antenna configured to send and receive wireless signals; radio front-end circuitry connected to the antenna and to processing circuitry, and configured to condition signals communicated between the antenna and the processing circuitry; the processing circuitry being configured to perform any of the steps of any of the Group A embodiments; an input interface connected to the processing circuitry and configured to allow input of information into the UE to be processed by the processing circuitry; an output interface connected to the processing circuitry and configured to output information from the UE that has been processed by the processing circuitry; and a battery connected to the processing circuitry and configured to supply power to the UE.

[0193] Embodiment 30: A host configured to operate in a communication system to provide an over-the-top (OTT) service, the host comprising: processing circuitry configured to provide user data; and a network interface configured to initiate transmission of the user data to a network node in a cellular network for transmission to a user equipment (UE), the network node having a communication interface and processing circuitry, the processing circuitry of the network node configured to perform any of the operations of any of the Group B embodiments to transmit the user data from the host to the UE.

[0194] Embodiment 31: The host of the previous embodiment, wherein: the processing circuitry of the host is configured to execute a host application that provides the user data; and the UE comprises processing circuitry configured to execute a client application associated with the host application to receive the transmission of user data from the host.

[0195] Embodiment 32: A method implemented in a host configured to operate in a communication system that further includes a network node and a user equipment (UE), the method comprising: providing user data for the UE; and initiating a transmission carrying the user data to the UE via a cellular network comprising the network node, wherein the network node performs any of the operations of any of the Group B embodiments to transmit the user data from the host to the UE.

[0196] Embodiment 33: The method of the previous embodiment, further comprising, at the network node, transmitting the user data provided by the host for the UE.

[0197] Embodiment 34: The method of any of the previous 2 embodiments, wherein the user data is provided at the host by executing a host application that interacts with a client application executing on the UE, the client application being associated with the host application.

[0198] Embodiment 35: A communication system configured to provide an over-the-top (OTT) service, the communication system comprising: a host comprising: processing circuitry configured to provide user data for a user equipment (UE), the user data being associated with the over-the-top service; and a network interface configured to initiate transmission of the user data toward a cellular network node for transmission to the UE, the network node having a communication interface and processing circuitry, the processing circuitry of the network node configured to perform any of the operations of any of the Group B embodiments to transmit the user data from the host to the UE.

[0199] Embodiment 36: The communication system of the previous embodiment, further comprising: the network node; and / or the UE.

[0200] Embodiment 37: A host configured to operate in a communication system to provide an over-the-top (OTT) service, the host comprising: processing circuitry configured to initiate receipt of user data; and a network interface configured to receive the user data from a network node in a cellular network, the network node having a communication interface and processing circuitry, the processing circuitry of the network node configured to perform any of the operations of any of the Group B embodiments to receive the user data from a user equipment (UE) for the host.

[0201] Embodiment 38: The host of the previous 2 embodiments, wherein: the processing circuitry of the host is configured to execute a host application that receives the user data; and the host application is configured to interact with a client application executing on the UE, the client application being associated with the host application.

[0202] Embodiment 39: The host of the any of the previous 2 embodiments, wherein the initiating receipt of the user data comprises requesting the user data.

[0203] Embodiment 40: A method implemented by a host configured to operate in a communication system that further includes a network node and a user equipment (UE), the method comprising: at the host, initiating receipt of user data from the UE, the user data originating from a transmission which the network node has received from the UE, wherein the network node performs any of the steps of any of the Group B embodiments to receive the user data from the UE for the host.

[0204] Embodiment 41: The method of the previous embodiment, further comprising at the network node, transmitting the received user data to the host.

[0205] Embodiment 42: A host configured to operate in a communication system to provide an over-the-top (OTT) service, the host comprising: processing circuitry configured to provide user data; and a network interface configured to initiate transmission of the user data to a cellular network for transmission to a user equipment (UE), wherein the UE comprises a communication interface and processing circuitry, the communication interface and processing circuitry of the UE being configured to perform any of the operations of any of the Group A embodiments to receive the user data from the host.

[0206] Embodiment 43: The host of the previous embodiment, wherein the cellular network further includes a network node configured to communicate with the UE to transmit the user data to the UE from the host.

[0207] Embodiment 44: The host of the previous 2 embodiments, wherein: the processing circuitry of the host is configured to execute a host application, thereby providing the user data; and the host application is configured to interact with a client application executing on the UE, the client application being associated with the host application.

[0208] Embodiment 45: A method implemented by a host operating in a communication system that further includes a network node and a user equipment (UE), the method comprising: providing user data for the UE; and initiating a transmission carrying the user data to the UE via a cellular network comprising the network node, wherein the UE performs any of the operations of any of the Group A embodiments to receive the user data from the host.

[0209] Embodiment 46: The method of the previous embodiment, further comprising: at the host, executing a host application associated with a client application executing on the UE to receive the user data from the host application.

[0210] Embodiment 47: The method of the previous embodiment, further comprising: at the host, transmitting input data to the client application executing on the UE, the input data being provided by executing the host application, wherein the user data is provided by the client application in response to the input data from the host application.

[0211] Embodiment 48: A host configured to operate in a communication system to provide an over-the-top (OTT) service, the host comprising: processing circuitry configured to provide user data; and a network interface configured to initiate transmission of the user data to a cellular network for transmission to a user equipment (UE), wherein the UE comprises a communication interface and processing circuitry, the communication interface and processing circuitry of the UEbeing configured to perform any of the steps of any of the Group A embodiments to transmit the user data to the host.

[0212] Embodiment 49: The host of the previous embodiment, wherein the cellular network further includes a network node configured to communicate with the UE to transmit the user data from the UE to the host.

[0213] Embodiment 50: The host of the previous 2 embodiments, wherein: the processing circuitry of the host is configured to execute a host application, thereby providing the user data; and the host application is configured to interact with a client application executing on the UE, the client application being associated with the host application.

[0214] Embodiment 51: A method implemented by a host configured to operate in a communication system that further includes a network node and a user equipment (UE), the method comprising: at the host, receiving user data transmitted to the host via the network node by the UE, wherein the UE performs any of the steps of any of the Group A embodiments to transmit the user data to the host.

[0215] Embodiment 52: The method of the previous embodiment, further comprising: at the host, executing a host application associated with a client application executing on the UE to receive the user data from the UE.

[0216] Embodiment 53: The method of the previous 2 embodiments, further comprising: at the host, transmitting input data to the client application executing on the UE, the input data being provided by executing the host application, wherein the user data is provided by the client application in response to the input data from the host application.

Claims

CLAIMS 1. A method performed by a User Equipment, UE, the method comprising: receiving (800) a Channel State Information (CSI) report configuration from a network node for reporting phase differences associated to a plurality of Downlink Reference Signals, DL-RSs; performing (802) phase measurement based on the plurality of DL-RSs; determining (804) phase differences associated with the plurality of DL-RSs; and reporting (806), to the network node, the determined phase differences.

2. The method of claim 1 wherein determining the phase differences further comprises: determining a phase difference for each of the plurality of DL-RSs based on the phase measurement, where the phase difference is with respect to a reference DL-RS.

3. The method of claim 2 further comprising: determining the reference DL-RS, where the reference DL-RS is one of the plurality of DL-RSs; and reporting the determined reference DL-RS to the network node.

4. The method of claim 3 wherein reporting the determined phase differences further comprises reporting the determined reference DL-RS.

5. The method of any of claims 1-4 wherein the phase difference associated to the reference DL-RS is zero and is not reported.

6. The method of any of claims 1-5 wherein each of the reported determined phase differences indicates a uniformly quantized phase difference between 0 to 2N , where the number of quantized points is configurable by higher layer signaling.

7. The method of claim 6, wherein the number of quantized points is indicated in the CSI report configuration.

8. The method of any of claims 1-7 wherein the plurality of DL-RSs are a plurality of Non- Zero Power CSI Reference Signal, NZP CSI-RS, resources.

9. The method of any of claims 1-8 wherein each of the plurality of NZP CSI-RS resource is a single port NZP CSI-RS resource.

10. The method of any of claims 1-9 wherein: for each TRP, precoding is applied to the associated CSI-RS at each RB with a precoding matrix determined for the RB and the TRP.

11. The method of any of claims 1-10 wherein: the phase differences associated to N (N>1) DL-RSs can be represent by a complex vector ^ = ^1, ^ !"# , … , ^ !"$%^ , where &'∈ {0, ^*+, ^*∙^+, ... , ^*(+ ^)+ } is the phase difference between the ith and the first DL-RS,12. The method of any of claims 1-11 wherein: the CSI-RS transmitted at each frequency or RB from each TRP is precoded according to a respective precoder determined at the frequency or RB.

13. The method of any of claims 1-12 wherein: time delay and frequency differences between TRP can be either pre-compensated at the network for the CSI-RS before being transmitted or at the UE.

14. The method of any of claims 1-13 wherein: RI and / or CQI are also reported based on the channel measurements.

15. A method performed by a network node, the method comprising: transmitting (800) a Channel State Information, CSI, report configuration to a User Equipment, UE, for reporting phase differences associated to a plurality of Downlink Reference Signals, DL-RSs; and receiving a report (806), from the UE, comprising phase differences associated with different DL-RSs.

16. The method of claim 15 wherein determining the phase differences further comprises: determining a phase difference for each of the plurality of DL-RSs based on the phase measurement, where the phase difference is with respect to a reference DL-RS.

17. The method of claim 16 further comprising:receiving a report of the determined reference DL-RS.

18. The method of claim 17 wherein receiving the report comprising the determined phase differences further comprises: the determined reference DL-RS.

19. The method of any of claims 15-18 wherein the phase difference associated to the reference DL-RS is zero and is not reported.

20. The method of any of claims 15-19 wherein each of the reported determined phase differences indicates a uniformly quantized phase difference between 0 to 2N, where the number of quantized points is configurable by higher layer signaling.

21. The method of claim 20, wherein the number of quantized points is indicated in the CSI report configuration.

22. The method of any of claims 15-21 wherein the plurality of DL-RSs are a plurality of Non-Zero Power CSI Reference Signal, NZP CSI-RS, resources.

23. The method of any of claims 15-22 wherein each of the plurality of NZP CSI-RS resource is a single port NZP CSI-RS resource.

24. The method of any of claims 15-23 wherein: for each TRP, precoding is applied to the associated CSI-RS at each RB with a precoding matrix determined for the RB and the TRP.

25. The method of any of claims 15-24 wherein: the phase differences associated to N (N>1) DL-RSs can be represent by a complex vector ^ = ^1, ^ !"# , … , ^ !"$%^ , where &'∈ {0, ^* , ^*∙^ , ... , ^*(+ ^)} is the phase difference betw+ + + een the ith and the first DL-RS,26. The method of any of claims 15-25 wherein: the CSI-RS transmitted at each frequency or RB from each TRP is precoded according to a respective precoder determined at the frequency or RB.

27. The method of any of claims 15-26 wherein: time delay and frequency differences betweenTRP can be either pre-compensated at the network for the CSI-RS before being transmitted or at the UE.

28. A User Equipment, UE, (1000) comprising processing circuitry (1002) and memory (1010), the memory (1010) comprising instructions to cause the UE (1000) to: receive (800) a Channel State Information (CSI) report configuration from a network node for reporting phase differences associated to a plurality of Downlink Reference Signals, DL-RSs; perform (802) phase measurement based on the plurality of DL-RSs; determine (804) phase differences associated with the plurality of DL-RSs; and report (806), to the network node, the determined phase differences.

29. The UE (1000) of claim 25 further comprising instructions to cause the UE (1000) to: implement any of the features of claims 2-14.

30. A computer-readable medium comprising instructions which, when executed on at least one processor, cause the at least one processor to carry out the method according to any one of claims 1 to 14.

31. A network node (800) comprising processing circuitry (1102) and memory (1104), the memory (1104) comprising instructions to cause the network node (1100) to: transmit (800) a Channel State Information (CSI) report configuration to a User Equipment, UE, for reporting phase differences associated to a plurality of Downlink Reference Signals, DL-RSs; and receive a report (806), from the UE, comprising phase differences associated with different DL-RSs.

32. The network node (1100) of claim 28 further comprising instructions to cause the network node (1100) to: implement any of the features of claims 16-27.

33. A computer-readable medium comprising instructions which, when executed on at least one processor, cause the at least one processor to carry out the method according to any one of claims 15 to 27.

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