WO2024035431A1

WO2024035431A1 - Pre-compensation of phase center offset on uplink carrier phase positioning

Info

Publication number: WO2024035431A1
Application number: PCT/US2022/074762
Authority: WO
Inventors: Ryan Keating; Hyun-Su Cha; Johannes Harrebek; Simon Svendsen
Original assignee: Nokia Technologies Oy; Nokia Of America Corporation
Priority date: 2022-08-10
Filing date: 2022-08-10
Publication date: 2024-02-15

Abstract

Systems, methods, apparatuses, and computer program products for pre- compensation of phase center offset (PCO) on uplink (UL) carrier phase (CP) positioning. A method may include receiving pre-compensation assistance data from a first network element. The method may also include determining pre-compensating phase center offset applied for transmission of reference signals per second network element based on at least the pre-compensation assistance data. The method may further include transmitting, to the first network element, an indication indicating a mapping of the signal transmission that has been pre-compensated.

Description

PRE-COMPENSATION OF PHASE CENTER OFFSET ON UPLINK CARRIER PHASE POSITIONING

FIELD:

[0001] Some example embodiments may generally relate to mobile or wireless telecommunication systems, such as Long Term Evolution (LTE) or fifth generation (5G) new radio (NR) access technology, or 5G beyond, or other communications systems. For example, certain example embodiments may relate to apparatuses, systems, and/or methods for pre-compensation of phase center offset (PCO) on uplink (UL) carrier phase (CP) positioning.

BACKGROUND:

[0002] Examples of mobile or wireless telecommunication systems may include the Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (UTRAN), Long Term Evolution (LTE) Evolved UTRAN (E-UTRAN), LTE-Advanced (LTE-A), MulteFire, LTE-A Pro, and/or fifth generation (5G) radio access technology or new radio (NR) access technology. Fifth generation (5G) wireless systems refer to the next generation (NG) of radio systems and network architecture. 5G network technology is mostly based on new radio (NR) technology, but the 5G (or NG) network can also build on E-UTRAN radio. It is estimated that NR may provide bitrates on the order of 10-20 Gbit/s or higher, and may support at least enhanced mobile broadband (eMBB) and ultra-reliable low-latency communication (URLLC) as well as massive machine-type communication (mMTC). NR is expected to deliver extreme broadband and ultra-robust, low-latency connectivity and massive networking to support the Internet of Things (loT).

SUMMARY:

[0003] Some example embodiments may be directed to a method. The method may include receiving pre-compensation assistance data from a first network element. The method may also include determining pre-compensating phase center offset applied for transmission of reference signals per second network element based on at least the pre-compensation assistance data. The method may further include transmitting, to the first network element, an indication indicating a mapping of the signal transmission that has been pre-compensated. [0004] Other example embodiments may be directed to an apparatus. The apparatus may include at least one processor and at least one memory including computer program code. The at least one memory and computer program code may also be configured to, with the at least one processor, cause the apparatus at least to receive pre-compensation assistance data from a first network element. The apparatus may also be caused to determine precompensating phase center offset applied for transmission of reference signals per second network element based on at least the pre-compensation assistance data. The apparatus may further be caused to transmit, to the first network element, an indication indicating a mapping of the signal transmission that has been pre-compensated.

[0005] Other example embodiments may be directed to an apparatus. The apparatus may include means for receiving pre-compensation assistance data from a first network element. The apparatus may also include means for determining pre-compensating phase center offset applied for transmission of reference signals per second network element based on at least the pre-compensation assistance data. The apparatus may further include means for transmitting, to the first network element, an indication indicating a mapping of the signal transmission that has been pre-compensated.

[0006] In accordance with other example embodiments, a non-transitory computer readable medium may be encoded with instructions that may, when executed in hardware, perform a method. The method may include receiving pre-compensation assistance data from a first network element. The method may also include determining pre-compensating phase center offset applied for transmission of reference signals per second network element based on at least the pre-compensation assistance data. The method may further include transmitting, to the first network element, an indication indicating a mapping of the signal transmission that has been pre-compensated.

[0007] Other example embodiments may be directed to a computer program product that performs a method. The method may include receiving pre-compensation assistance data from a first network element. The method may also include determining pre-compensating phase center offset applied for transmission of reference signals per second network element based on at least the pre-compensation assistance data. The method may further include transmitting, to the first network element, an indication indicating a mapping of the signal transmission that has been pre-compensated.

[0008] Other example embodiments may be directed to an apparatus that may include circuitry configured to receive pre-compensation assistance data from a first network element. The apparatus may also include circuitry configured to determine precompensating phase center offset applied for transmission of reference signals per second network element based on at least the pre-compensation assistance data. The apparatus may further include circuitry configured to transmit, to the first network element, an indication indicating a mapping of the signal transmission that has been pre-compensated.

[0009] Certain example embodiments may be directed to a method. The method may include receiving, from a network element, a pre-compensated mapping comprising an indication of a signal transmission resource that has been pre-compensated. The method may further include receiving a signal transmission from a reference user equipment, and a signal transmission from a target user equipment. The method may also include measuring a carrier phase based on the pre-compensated mapping, the signal transmission from the reference user equipment, and the signal transmission from the target user equipment. In addition, the method may include reporting the carrier phase to the network element.

[0010] Other example embodiments may be directed to an apparatus. The apparatus may include at least one processor and at least one memory including computer program code. The at least one memory and computer program code may be configured to, with the at least one processor, cause the apparatus at least to receive, from a network element, a precompensated mapping comprising an indication of a signal transmission resource that has been pre-compensated. The apparatus may also be caused to receive a signal transmission from a reference user equipment, and a signal transmission from a target user equipment. The apparatus may further be caused to measure a carrier phase based on the precompensated mapping, the signal transmission from the reference user equipment, and the signal transmission from the target user equipment. In addition, the apparatus may be caused to report the carrier phase to the network element.

[0011] Other example embodiments may be directed to an apparatus. The apparatus may include means for receiving, from a network element, a pre-compensated mapping comprising an indication of a signal transmission resource that has been pre-compensated. The apparatus may also include means for receiving a signal transmission from a reference user equipment, and a signal transmission from a target user equipment. The apparatus may further include means for measuring a carrier phase based on the pre-compensated mapping, the signal transmission from the reference user equipment, and the signal transmission from the target user equipment. In addition, the apparatus may include means for reporting the carrier phase to the network element.

[0012] In accordance with other example embodiments, a non-transitory computer readable medium may be encoded with instructions that may, when executed in hardware, perform a method. The method may include receiving, from a network element, a pre-compensated mapping comprising an indication of a signal transmission resource that has been precompensated. The method may further include receiving a signal transmission from a reference user equipment, and a signal transmission from a target user equipment. The method may also include measuring a carrier phase based on the pre-compensated mapping, the signal transmission from the reference user equipment, and the signal transmission from the target user equipment. In addition, the method may include reporting the carrier phase to the network element.

[0013] Other example embodiments may be directed to a computer program product that performs a method. The method may include receiving, from a network element, a precompensated mapping comprising an indication of a signal transmission resource that has been pre-compensated. The method may further include receiving a signal transmission from a reference user equipment, and a signal transmission from a target user equipment. The method may also include measuring a carrier phase based on the pre-compensated mapping, the signal transmission from the reference user equipment, and the signal transmission from the target user equipment. In addition, the method may include reporting the carrier phase to the network element.

[0014] Other example embodiments may be directed to an apparatus that may include circuitry configured to receive, from a network element, a pre-compensated mapping comprising an indication of a signal transmission resource that has been pre-compensated. The apparatus may also include circuitry configured to receive a signal transmission from a reference user equipment, and a signal transmission from a target user equipment. The apparatus may further include circuitry configured to measure a carrier phase based on the pre-compensated mapping, the signal transmission from the reference user equipment, and the signal transmission from the target user equipment. In addition, the apparatus may include circuitry configured to report the carrier phase to the network element.

[0015] Certain example embodiments may be directed to a method. The method may include transmitting pre-compensation assistance data to a reference user equipment. The method may also include receiving, from the reference user equipment, an indication indicating a mapping of a signal transmission that has been pre-compensated to a network element based on the pre-compensation assistance data. The method may further include transmitting, to the network element, an indication of the signal transmission resource that that has been pre-compensated. In addition, the method may include receiving a carrier phase report from the network element based on the indication.

[0016] Other example embodiments may be directed to an apparatus. The apparatus may include at least one processor and at least one memory including computer program code. The at least one memory and computer program code may be configured to, with the at least one processor, cause the apparatus at least to transmit pre-compensation assistance data to a reference user equipment. The apparatus may also be caused to receive, from the reference user equipment, an indication indicating a mapping of a signal transmission that has been pre-compensated to a network element based on the pre-compensation assistance data. The apparatus may further be caused to transmit, to the network element, an indication of the signal transmission resource that that has been pre -compensated. In addition, the apparatus may be caused to receive a carrier phase report from the network element based on the indication.

[0017] Other example embodiments may be directed to an apparatus. The apparatus may include means for transmitting pre-compensation assistance data to a reference user equipment. The apparatus may also include means for receiving, from the reference user equipment, an indication indicating a mapping of a signal transmission that has been precompensated to a network element based on the pre-compensation assistance data. The apparatus may further include means for transmitting, to the network element, an indication of the signal transmission resource that that has been pre-compensated. In addition, the apparatus may include means for receiving a carrier phase report from the network element based on the indication.

[0018] In accordance with other example embodiments, a non-transitory computer readable medium may be encoded with instructions that may, when executed in hardware, perform a method. The method may include transmitting pre-compensation assistance data to a reference user equipment. The method may also include receiving, from the reference user equipment, an indication indicating a mapping of a signal transmission that has been precompensated to a network element based on the pre-compensation assistance data. The method may further include transmitting, to the network element, an indication of the signal transmission resource that that has been pre-compensated. In addition, the method may include receiving a carrier phase report from the network element based on the indication.

[0019] Other example embodiments may be directed to a computer program product that performs a method. The method may include transmitting pre-compensation assistance data to a reference user equipment. The method may also include receiving, from the reference user equipment, an indication indicating a mapping of a signal transmission that has been pre-compensated to a network element based on the pre-compensation assistance data. The method may further include transmitting, to the network element, an indication of the signal transmission resource that that has been pre-compensated. In addition, the method may include receiving a carrier phase report from the network element based on the indication. [0020] Other example embodiments may be directed to an apparatus that may include circuitry configured to transmit pre-compensation assistance data to a reference user equipment. The apparatus may also include circuitry configured to receive, from the reference user equipment, an indication indicating a mapping of a signal transmission that has been pre-compensated to a network element based on the pre-compensation assistance data. The apparatus may further include circuitry configured to transmit, to the network element, an indication of the signal transmission resource that that has been precompensated. In addition, the apparatus may include circuitry configured to receive a carrier phase report from the network element based on the indication.

BRIEF DESCRIPTION OF THE DRAWINGS:

[0021] For proper understanding of example embodiments, reference should be made to the accompanying drawings, wherein:

[0022] FIG. 1 illustrates an example UE mmWave 1:8 antenna array.

[0023] FIG. 2(a) illustrates an example of a user equipment (UE) antenna array radiation phase variation.

[0024] FIG. 2(b) illustrates another example of a UE antenna array radiation phase variation.

[0025] FIG. 3 illustrates an example uplink carrier phase.

[0026] FIG. 4 illustrates an example signal flow diagram, according to certain example embodiments.

[0027] FIG. 5 illustrates an example flow diagram of a method, according to certain example embodiments.

[0028] FIG. 6 illustrates an example flow diagram of another method, according to certain example embodiments.

[0029] FIG. 7 illustrates an example flow diagram of a further method, according to certain example embodiments.

[0030] FIG. 8 illustrates a set of apparatuses, according to certain example embodiments.

DETAILED DESCRIPTION:

[0031] It will be readily understood that the components of certain example embodiments, as generally described and illustrated in the figures herein, may be arranged and designed in a wide variety of different configurations. The following is a detailed description of some example embodiments of systems, methods, apparatuses, and computer program products for pre-compensation of phase center offset (PCO) on uplink (UL) carrier phase (CP) positioning.

[0032] The features, structures, or characteristics of example embodiments described throughout this specification may be combined in any suitable manner in one or more example embodiments. For example, the usage of the phrases “certain embodiments,” “an example embodiment,” “some embodiments,” or other similar language, throughout this specification refers to the fact that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment. Thus, appearances of the phrases “in certain embodiments,” “an example embodiment,” “in some embodiments,” “in other embodiments,” or other similar language, throughout this specification do not necessarily refer to the same group of embodiments, and the described features, structures, or characteristics may be combined in any suitable manner in one or more example embodiments. Further, the terms “cell”, “node”, “gNB”, “network” or other similar language throughout this specification may be used interchangeably.

[0033] As used herein, “at least one of the following: <a list of two or more elements>” and “at least one of <a list of two or more elements>” and similar wording, where the list of two or more elements are joined by “and” or “or,” mean at least any one of the elements, or at least any two or more of the elements, or at least all the elements.

[0034] The technical specifications of 3^rd Generation Partnership Project (3GPP) have provided various positioning solutions related to downlink time difference of arrival (DL- TDOA), uplink time difference of arrival (UL-TDOA), downlink angle of departure (DL- AoD), uplink angle of arrival (UL-AoA), and multi-cell round trip time (Multi-RTT). In particular, 3GPP specifies solutions that enable RAT dependent (e.g., for both frequency range 1 (FR1) and frequency range 2 (FR2)) and RAT independent NR positioning techniques. In DL, a new positioning reference signal (PRS) may be introduced, and in UL, a new sounding reference signal (SRS) may be introduced. Thus, there has been a focus on providing positioning enhancements for improving positioning accuracy by mitigating UE Rx/Tx and/or gNB Rx/Tx timing delays. Solutions for accuracy improvement based on NR CP measurements have also been provided along with a focus on reusing PRS and SRS.

[0035] Assuming UL, in the CP positioning technique, a target UE may transmit UL reference signals such as SRS for positioning, and multiple transmit reception points (TRPs) may measure phase measurements, which may be used to estimate location of the target UEs. For the transmitted SRS resource from the Uth UE, the phase measurement at the i-th TRP may be denoted by: <Pik - di_k + c (8_k — 6i) + N_ik (1)

In equation (1), <pi_k = ~<Pik denotes the phase measurement in distance/cycles and leaves out repeated use of 2TT, and dj_k, c, 8_k, 8i, and N{_k represent respectively, actual geographical distance between the Uth UE and the i -th TRP, speed of light, internal clock bias at the Uth UE, internal clock bias at the i -th TRP, and integer ambiguity of the propagated wavelength. Similar to equation (1), the same equation may be derived for the j-th TRP such that <Pj_k = djk + ^c

and single difference measurement between two TRPs is described as the following equation:

In equation

[0036] From the single differential operation shown in equation (2), the UE clock bias may be cancelled, which is similar to the relative time of arrival (RTOA) measurement of UL- TDOA. The clock error between TRPs remains, but it may be cancelled by a double differential operation using measurements from the reference device.

[0037] Assuming that the A t h UE is a positioning reference unit (PRU), for the transmitted SRS from the PRU, the single difference measurement between the z-th TRP andj-th TRP may

In equation

8N- . In the end, the clock error between TRPs may be cancelled out. Here, clock bias may be considered at the UE and the TRP, which are the errors that explain the single difference and the double difference methods of the carrier phase method.

[0038] For a UE antenna phase center offset (PCO), a precise assessment of DL PRS time of arrival (TOA) and/or the UL SRS time of departure (TOD) may be essential for obtaining accurate positioning measurements, and highly accurate TOA/TOD at the UE. Precise assessment of DL PRS TOA and/or UL SRS TOD may also be essential for CP measurements to have a precise measure of the phase reference position for the signal being received or transmitted via the UE antenna.

[0039] FIG. 1 illustrates an example UE mmWave 1:8 antenna array. In particular, as illustrated in FIG. 1, the UE mmWave 1:8 antenna array is mounted on a UE form-factor design. The reference position illustrated in FIG. 1 is the antenna phase center, which may be fixed and aligned with the physical antenna reference point (ARP). However, the antenna phase center may not always align with the physical ARP, but may be located at an offset, as shown in FIG. 1.

[0040] The UE antenna array phase center location may be dynamic and sensitive to the actual UE form-factor design (with current flow influenced by physical dimensions, mounted proximity components, materials, etc.). The UE antenna array phase center location may also be sensitive to the antenna array cover (e.g., PC-ABS, glass), the AOA and polarization for broad beam configuration, the antenna array beam steering angel, AOA on the “banana” shape beam pattern for 1 dimensional antenna arrays, and the polarization at the used beam steering angle.

[0041] FIG. 2(a) illustrates an example of UE antenna array radiation phase variation, and FIG. 2(b) illustrates another example of UE antenna array radiation phase variation. In particular, the variation may be over a beam steering angle and direction of signal plus the associated offset in mm from the assumed ARP. As illustrated in FIG. 2(a), the phase plots for the UE form-factor with top mounted 1 : 8 array over beam steering angle and polarization is shown. In FIG. 2(b), the phase center offset in mm reference ARP for UE form-factor with top mounted 1:8 array over beam steering angle, AOA, and polarization is shown. As observed in FIGs. 2(a) and 2(b), the antenna array phase center may vary dynamically by several centimeters. If the variation is left uncompensated, the PCO may cause significant impairment resulting in reduced position estimation accuracy which is critical for centimeter accuracy applications such as industrial Internet of things (IIoT).

[0042] FIG. 3 illustrates an example UL CP. In UL CP, both the target UE and the PRU may transmit SRS for positioning. The TRPs may then measure both the CP of the target UE and PRU, and report the measurements to the LMF, which may then create the double differential measurements. The PCO of both the target UE and the PRU may impact the accuracy of the UL CP positioning if left uncompensated. Although there have been previous attempts to cover the case of the target UE post compensating the PCO impact, they may be inefficient since they would require the PRU to constantly receive signaling from the LMF to then report the PCO for particular SRS transmission. Thus, given that the PRU knows its location and its own orientation, and the locations of the TRPs are known at the LMF, it is inefficient to perform PCO post compensation.

[0043] Certain example embodiments provide a method for PCO pre-compensation by a PRU as part of UL CP positioning. For instance, FIG. 4 illustrates an example signal flow diagram, according to certain example embodiments. At 400, UL CP may be configured for a target UE (shown as “UE” in FIG. 4), and both the target UE and the PRU (reference UE) may be configured to transmit SRS for CP. At 405, the LMF may signal TRP locations and/or ID of the TRP to the PRU, which may be used (e.g., at 430) for the target UE’s UL CP session. At 410, the PRU may pre-compensate PCO during an SRS transmission on a per TRP basis using the location and orientation of the PRU. That is, in certain example embodiments, the PRU may determine, per TRP PCO, a PCO pre-compensation mapping. In some example embodiments, the PCO pre-compensation mapping may be between each SRS resource/repetition and the TRP that the SRS is intended for such that the mapping may inform the LMF which SRS transmission are PCO pre-compensated for which TRPs.

[0044] According to certain example embodiments, the PRU may pre-compensate the PCO for one TRP per SRS resource. A SRS resource may be defined by at least a time and frequency resource such as a transmission periodicity and occupied RBs within a uplink bandwidth part, and these may be configured by the gNB. Additionally, the gNB may configure spatial relation information in each SRS resource configuration so that the UE determines transmission beam for the SRS resource. For example, the PRU may be configured with spatial relation information for each SRS resource, and the configuration may include TRP ID. In one example embodiment, the PRU may use a fixed offset (e.g., PRU may use a PCO value to compensate for phase center offset during a certain time window) to pre-compensate PCO for a certain time domain (if the channel coherency (e.g., wireless channel is not fluctuating during a certain time, and is between the PRU and TRP is not different or less than a certain threshold) is preserved), and the PRU may report and/or update the pre-compensation information (e.g., pre-compensation PCO value to compensate for PCO when the PRU transmits each SRS resource, and information of which SRS transmissions are pre-compensated for which TRP) to the LMF. According to certain example embodiments, pre-compensation may involve adjusting the transmission timing such that the ARP is aligned with the antenna phase center.

[0045] For example, the LMF may configure a criterion e.g. , a threshold value) so that the PRU reports and/or updates the pre-compensation information (e.g., PCO offset per SRS resource). In certain example embodiments, if the PRU moves into a different location, the PCO pre-compensation may be different. However, if the changed PCO pre-compensation value is small such that it does not affect a positioning requirement, the PRU may not need to be updated. Additionally, the threshold value may be configured from the LMF considering a target positioning accuracy requirement. In other example embodiments, the PRU may update the pre-compensation information if the PRU location is changed more than a threshold value. According to certain example embodiments, the threshold value may be related to a variation/ change of the location of the PRU as the PRU may move. If the PRU moves, the PCO pre-compensation value may be different. For example, if the absolute distance of the PRU between t=t 1 and t=t2 changes more than a threshold, PRU may report the updated PCO pre-compensation. Additionally, in some example embodiments, the gNB may provide the PRU with channel coherency information for each TRP to help with the pre-compensation at the PRU. Further, in other example embodiments, the PRU may request the gNB to provide the channel coherency information for a TRP.

[0046] In certain example embodiments, in the pre-compensation of the PCO by the PRU, the PRU may pre-compensate PCO for one TRP per SRS occasion/instance. For example, when the SRS has a periodicity of 10 ms and across 4 instances of the periodicity (in a 40 ms time period), the PRU may pre-compensate PCO for 4 different TRPs; one TRP in each instance. For instance, in certain example embodiments, the PRU may pre-compensate PCO by considering the TRP location, and using different transmission beam direction. The PRU may also determine a pre-compensation value for each transmission beam direction based on PRU orientation.

[0047] According to certain example embodiments, in the pre-compensation of the PCO by the PRU, the PRU may pre-compensate PCT for one TRP per SRS repetition. For example, the SRS may have a repetition factor of 4 with a time gap of 2 slots. In the first repetition, the SRS may be pre-compensated for one TRP, and in the next repetition, another TRP.

[0048] Returning to FIG. 4, at 415, the PRU may indicate to the LMF, the above mapping of SRS transmission t TRP from operation 410 (i.e., either per SRS resource, per SRS occasion/instance, or per SRS repetition). In certain example embodiments, the mapping may indicate to the LMF which SRS resource/occasions/repetitions have been precompensated for which TRPs. The mapping may not indicate the PCO pre-compensation values. In other example embodiments, at 420, the LMF may optionally coordinate/indicate the mapping to the target UE and/or the serving TRP so that the target UE also uses the same time instances to transmit to those target TRPs as the PRU, and so that the SRS transmissions of the target UE may be aligned or coordinated with the SRS transmission of the PRU. By this coordination/indication, the Rx timing error due to Rx timing error group (TEG) may be common between the CP measurements of the target UE and the PRU, and it may be beneficial for differentiating operations.

[0049] At 425, the LMF may indicate to the TRPs which resources/occasions/repetitions have been pre-compensated so that the TRPs can measure only on the relevant resources/occasions/repetitions. The TRPs may then receive PRU SRS at 430, and receive target UE SRS at 435. Further, at 440, the TRPs may measure the carrier phase(s) based on the received information from 425, 430, and 435. At 445, the TRPs may report the phase measurements to the LMF. At 450, the EMF may estimate the UE location based on the received report of phase measurements. In certain example embodiments, the TRP may measure SRS on all the resources/occasions/repetitions, and may then use time stamp on measurement occasions for the EMF to filter the measurements. According to certain example embodiments, during the filtering, the EMF may look at the time stamps of the reported measurements, and select the time stamp(s) that corresponds to the appropriate PCO pre-compensation. For instance, if the PRU pre-compensates the SRS for TRP X during time stamp Y, then the EMF may use time stamp Y to select the carrier phase measurement for TRP X. Further, the measurements in this instance may correspond to positioning measurements measured from SRS resources transmitted from the PRU and the target UE.

[0050] FIG. 5 illustrates an example flow diagram of a method, according to certain example embodiments. In an example embodiment, the method of FIG. 5 may be performed by a network entity, or a group of multiple network elements in a 3GPP system, such as ETE or 5G-NR. For instance, in an example embodiment, the method of FIG. 5 may be performed by a UE or PRU similar to one of apparatuses 10 or 20 illustrated in FIG. 8.

[0051] According to certain example embodiments, the method of FIG. 5 may include, at 500, receiving pre-compensation assistance data from a first network element. The method may also include, at 505, determining pre-compensating phase center offset applied for transmission of reference signals per second network element based on at least the precompensation assistance data. The method may further include, at 510, transmitting, to the first network element, an indication indicating a mapping of the signal transmission that has been pre-compensated.

[0052] According to certain example embodiments, the pre-compensation of the phase center offset may be performed using at least one or more of the following location information of a reference user equipment, orientation information of the reference user equipment, a beam direction of the reference user equipment, or a beam beamwidth of the reference user equipment. According to other example embodiments, the pre-compensation assistance data comprises at least one of a location of the second network element or an identification of the second network element. According to some example embodiments, the pre-compensating the phase center offset for the second network element may include precompensating the phase center offset for one second network element per reference signal resource, pre-compensating the phase center offset for one second network element per reference signal transmission occasion, or pre-compensating the phase center offset for one second network element per reference signal transmission repetition. According to other example embodiments, when the phase center offset is pre-compensated for the one second network element per reference signal resource, the method may further receiving a configuration with spatial relation information for each signal transmission resource, and the identification of the second network element.

[0053] In certain example embodiments, when the phase center offset is pre-compensated for the one second network element per reference signal resource, the method may further include receiving channel coherency information for the second network element to assist with the pre-compensation. In other example embodiments, pre-compensating the phase center offset for one second network element per reference signal transmission occasion may include pre-compensating for a plurality of second network elements, one second network element in each instance of a plurality of instances. In some example embodiments, when the phase-center offset is pre-compensated for the one second network element per reference signal transmission repetition, the signal transmission may include a repetition factor with a time gap of a predefined number of slots. In further example embodiments, the method may also include updating pre-compensation information when a location change of a reference user equipment exceeds a threshold value. According to some example embodiments, the method may also include pre-compensating the phase center offset for a predetermined duration of time based on a fixed offset.

[0054] FIG. 6 illustrates an example of a flow diagram of another method, according to certain example embodiments. In an example embodiment, the method of FIG. 6 may be performed by a network entity, or a group of multiple network elements in a 3GPP system, such as LTE or 5G-NR. For instance, in an example embodiment, the method of FIG. 6 may be performed by a gNB, TRP, LMF, or any other device similar to one of apparatuses 10 or 20 illustrated in FIG. 8.

[0055] According to certain example embodiments, the method of FIG. 6 may include, at 600, receiving, from a network element, a pre-compensated mapping including an indication of a signal transmission resource that has been pre-compensated. The method may also include, at 605, receiving a signal transmission from a reference user equipment, and a signal transmission from a target user equipment. The method may further include, at 610, measuring a carrier phase based on the pre-compensated mapping, the signal transmission from the reference user equipment, and the signal transmission from the target user equipment. In addition, the method may include, at 615, reporting the carrier phase to the network element.

[0056] According to certain example embodiments, the carrier phase may be at least one of a non-difference carrier phase, a single differenced carrier phase, or a doubled differenced carrier phase. According to other example embodiments, the method may also include obtaining measurements of the signal transmission from the reference user equipment, and the signal transmission from the target user equipment. According to other example embodiments, the method may further include filtering the measurements based on time stamps on measurement occasions for the network element.

[0057] FIG. 7 illustrates an example of a flow diagram of a further method, according to certain example embodiments. In an example embodiment, the method of FIG. 7 may be performed by a network entity, or a group of multiple network elements in a 3GPP system, such as LTE or 5G-NR. For instance, in an example embodiment, the method of FIG. 7 may be performed by a gNB, TRP, LMF, or any other device similar to one of apparatuses 10 or 20 illustrated in FIG. 8.

[0058] According to certain example embodiments, the method of FIG. 7 may include, at 700, transmitting pre-compensation assistance data to a reference user equipment. The method may also include, at 705, receiving, from the reference user equipment, an indication indicating a mapping of a signal transmission that has been pre-compensated to a network element based on the pre-compensation assistance data. The method may further include, at 710, transmitting, to the network element, an indication of the signal transmission resource that has been pre-compensated. In addition, the method may include, at 715, receiving a carrier phase report from the network element based on the indication.

[0059] According to certain example embodiments, the pre-compensation assistance data may include a location or an identification of network element to be used for an uplink carrier phase session of a target user equipment. According to some example embodiments, the method may also include coordinating the mapping to the reference user equipment to enable a target user equipment to use same time instances to perform transmission to the target user equipment. According to other example embodiments, the method may further include configuring a criterion so that the reference user equipment reports or updates pre- compensation information.

[0060] FIG. 8 illustrates a set of apparatus 10 and 20 according to certain example embodiments. In certain example embodiments, the apparatus 10 may be an element in a communications network or associated with such a network, such as a UE, mobile equipment (ME), mobile station, mobile device, stationary device, loT device, or other device. It should be noted that one of ordinary skill in the art would understand that apparatus 10 may include components or features not shown in FIG. 8.

[0061] In some example embodiments, apparatus 10 may include one or more processors, one or more computer-readable storage medium (for example, memory, storage, or the like), one or more radio access components (for example, a modem, a transceiver, or the like), and/or a user interface. In some example embodiments, apparatus 10 may be configured to operate using one or more radio access technologies, such as GSM, LTE, LTE-A, NR, 5G, WLAN, WiFi, NB-IoT, Bluetooth, NFC, MulteFire, and/or any other radio access technologies. It should be noted that one of ordinary skill in the art would understand that apparatus 10 may include components or features not shown in FIG. 8.

[0062] As illustrated in the example of FIG. 8, apparatus 10 may include or be coupled to a processor 12 for processing information and executing instructions or operations. Processor 12 may be any type of general or specific purpose processor. In fact, processor 12 may include one or more of general-purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs), field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), and processors based on a multicore processor architecture, as examples. While a single processor 12 is shown in FIG. 8, multiple processors may be utilized according to other example embodiments. For example, it should be understood that, in certain example embodiments, apparatus 10 may include two or more processors that may form a multiprocessor system (e.g., in this case processor 12 may represent a multiprocessor) that may support multiprocessing. According to certain example embodiments, the multiprocessor system may be tightly coupled or loosely coupled (e.g., to form a computer cluster).

[0063] Processor 12 may perform functions associated with the operation of apparatus 10 including, as some examples, precoding of antenna gain/phase parameters, encoding and decoding of individual bits forming a communication message, formatting of information, and overall control of the apparatus 10, including processes illustrated in FIGs. 1-5.

[0064] Apparatus 10 may further include or be coupled to a memory 14 (internal or external), which may be coupled to processor 12, for storing information and instructions that may be executed by processor 12. Memory 14 may be one or more memories and of any type suitable to the local application environment, and may be implemented using any suitable volatile or nonvolatile data storage technology such as a semiconductor-based memory device, a magnetic memory device and system, an optical memory device and system, fixed memory, and/or removable memory. For example, memory 14 can be comprised of any combination of random access memory (RAM), read only memory (ROM), static storage such as a magnetic or optical disk, hard disk drive (HDD), or any other type of non-transitory machine or computer readable media. The instructions stored in memory 14 may include program instructions or computer program code that, when executed by processor 12, enable the apparatus 10 to perform tasks as described herein.

[0065] In certain example embodiments, apparatus 10 may further include or be coupled to (internal or external) a drive or port that is configured to accept and read an external computer readable storage medium, such as an optical disc, USB drive, flash drive, or any other storage medium. For example, the external computer readable storage medium may store a computer program or software for execution by processor 12 and/or apparatus 10 to perform any of the methods illustrated in FIGs. 1-5.

[0066] In some example embodiments, apparatus 10 may also include or be coupled to one or more antennas 15 for receiving a downlink signal and for transmitting via an UL from apparatus 10. Apparatus 10 may further include a transceiver 18 configured to transmit and receive information. The transceiver 18 may also include a radio interface (e.g., a modem) coupled to the antenna 15. The radio interface may correspond to a plurality of radio access technologies including one or more of GSM, LTE, LTE-A, 5G, NR, WLAN, NB-IoT, Bluetooth, BT-LE, NFC, RFID, UWB, and the like. The radio interface may include other components, such as filters, converters (for example, digital-to-analog converters and the like), symbol demappers, signal shaping components, an Inverse Fast Fourier Transform (IFFT) module, and the like, to process symbols, such as OFDMA symbols, carried by a downlink or an UL.

[0067] For instance, transceiver 18 may be configured to modulate information on to a carrier waveform for transmission by the antenna(s) 15 and demodulate information received via the antenna(s) 15 for further processing by other elements of apparatus 10. In other example embodiments, transceiver 18 may be capable of transmitting and receiving signals or data directly. Additionally or alternatively, in some example embodiments, apparatus 10 may include an input and/or output device (I/O device). In certain example embodiments, apparatus 10 may further include a user interface, such as a graphical user interface or touchscreen.

[0068] In certain example embodiments, memory 14 stores software modules that provide functionality when executed by processor 12. The modules may include, for example, an operating system that provides operating system functionality for apparatus 10. The memory may also store one or more functional modules, such as an application or program, to provide additional functionality for apparatus 10. The components of apparatus 10 may be implemented in hardware, or as any suitable combination of hardware and software. According to certain example embodiments, apparatus 10 may optionally be configured to communicate with apparatus 20 via a wireless or wired communications link 70 according to any radio access technology, such as NR.

[0069] According to certain example embodiments, processor 12 and memory 14 may be included in or may form a part of processing circuitry or control circuitry. In addition, in some example embodiments, transceiver 18 may be included in or may form a part of transceiving circuitry.

[0070] For instance, in certain example embodiments, apparatus 10 may be controlled by memory 14 and processor 12 to receive pre-compensation assistance data from a first network element. Apparatus 10 may also be controlled by memory 14 and processor 12 to determine pre-compensating phase center offset applied for transmission of reference signals per second network element based on at least the pre-compensation assistance data. Apparatus 10 may further be controlled by memory 14 and processor 12 to transmit, to the first network element, an indication indicating a mapping of the signal transmission that has been pre-compensated to the second network element.

[0071] As illustrated in the example of FIG. 8, apparatus 20 may be a network, core network element, or element in a communications network or associated with such a network, such as a gNB, LMF, or TRP. It should be noted that one of ordinary skill in the art would understand that apparatus 20 may include components or features not shown in FIG. 8.

[0072] As illustrated in the example of FIG. 8, apparatus 20 may include a processor 22 for processing information and executing instructions or operations. Processor 22 may be any type of general or specific purpose processor. For example, processor 22 may include one or more of general-purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs), field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), and processors based on a multi-core processor architecture, as examples. While a single processor 22 is shown in FIG. 8, multiple processors may be utilized according to other example embodiments. For example, it should be understood that, in certain example embodiments, apparatus 20 may include two or more processors that may form a multiprocessor system (e.g., in this case processor 22 may represent a multiprocessor) that may support multiprocessing. In certain example embodiments, the multiprocessor system may be tightly coupled or loosely coupled (e.g., to form a computer cluster).

[0073] According to certain example embodiments, processor 22 may perform functions associated with the operation of apparatus 20, which may include, for example, precoding of antenna gain/phase parameters, encoding and decoding of individual bits forming a communication message, formatting of information, and overall control of the apparatus 20, including processes illustrated in FIGs. 1-4, 6, and 7.

[0074] Apparatus 20 may further include or be coupled to a memory 24 (internal or external), which may be coupled to processor 22, for storing information and instructions that may be executed by processor 22. Memory 24 may be one or more memories and of any type suitable to the local application environment, and may be implemented using any suitable volatile or nonvolatile data storage technology such as a semiconductor-based memory device, a magnetic memory device and system, an optical memory device and system, fixed memory, and/or removable memory. For example, memory 24 can be comprised of any combination of random access memory (RAM), read only memory (ROM), static storage such as a magnetic or optical disk, hard disk drive (HDD), or any other type of non-transitory machine or computer readable media. The instructions stored in memory 24 may include program instructions or computer program code that, when executed by processor 22, enable the apparatus 20 to perform tasks as described herein.

[0075] In certain example embodiments, apparatus 20 may further include or be coupled to (internal or external) a drive or port that is configured to accept and read an external computer readable storage medium, such as an optical disc, USB drive, flash drive, or any other storage medium. For example, the external computer readable storage medium may store a computer program or software for execution by processor 22 and/or apparatus 20 to perform the methods illustrated in FIGs. 1-4, 6, and 7.

[0076] In certain example embodiments, apparatus 20 may also include or be coupled to one or more antennas 25 for transmitting and receiving signals and/or data to and from apparatus 20. Apparatus 20 may further include or be coupled to a transceiver 28 configured to transmit and receive information. The transceiver 28 may include, for example, a plurality of radio interfaces that may be coupled to the antenna(s) 25. The radio interfaces may correspond to a plurality of radio access technologies including one or more of GSM, NB- loT, LTE, 5G, WLAN, Bluetooth, BT-LE, NFC, radio frequency identifier (RFID), ultrawideband (UWB), MulteFire, and the like. The radio interface may include components, such as filters, converters (for example, digital-to-analog converters and the like), mappers, a Fast Fourier Transform (FFT) module, and the like, to generate symbols for a transmission via one or more downlinks and to receive symbols (for example, via an UL).

[0077] As such, transceiver 28 may be configured to modulate information on to a carrier waveform for transmission by the antenna(s) 25 and demodulate information received via the antenna(s) 25 for further processing by other elements of apparatus 20. In other example embodiments, transceiver 18 may be capable of transmitting and receiving signals or data directly. Additionally or alternatively, in some example embodiments, apparatus 20 may include an input and/or output device (I/O device).

[0078] In certain example embodiment, memory 24 may store software modules that provide functionality when executed by processor 22. The modules may include, for example, an operating system that provides operating system functionality for apparatus 20. The memory may also store one or more functional modules, such as an application or program, to provide additional functionality for apparatus 20. The components of apparatus 20 may be implemented in hardware, or as any suitable combination of hardware and software.

[0079] According to some example embodiments, processor 22 and memory 24 may be included in or may form a part of processing circuitry or control circuitry. In addition, in some example embodiments, transceiver 28 may be included in or may form a part of transceiving circuitry.

[0080] As used herein, the term “circuitry” may refer to hardware-only circuitry implementations (e.g., analog and/or digital circuitry), combinations of hardware circuits and software, combinations of analog and/or digital hardware circuits with software/firmware, any portions of hardware processor(s) with software (including digital signal processors) that work together to cause an apparatus (e.g., apparatus 10 and 20) to perform various functions, and/or hardware circuit(s) and/or processor(s), or portions thereof, that use software for operation but where the software may not be present when it is not needed for operation. As a further example, as used herein, the term “circuitry” may also cover an implementation of merely a hardware circuit or processor (or multiple processors), or portion of a hardware circuit or processor, and its accompanying software and/or firmware. The term circuitry may also cover, for example, a baseband integrated circuit in a server, cellular network node or device, or other computing or network device.

[0081] For instance, in certain example embodiments, apparatus 20 may be controlled by memory 24 and processor 22 to receive, from a network element, a pre-compensated mapping comprising an indication of a signal transmission resource that has been precompensated. Apparatus 20 may also be controlled by memory 24 and processor 22 to receive a signal transmission from a reference user equipment, and a signal transmission from a target user equipment. Apparatus 20 may further be controlled by memory 24 and processor 22 to measure a carrier phase based on the pre-compensated mapping, the signal transmission from the reference user equipment, and the signal transmission from the target user equipment. Further, apparatus 20 may be controlled by memory 24 and processor 22 to report the carrier phase to the network element.

[0082] In certain example embodiments, apparatus 20 may be controlled by memory 24 and processor 22 to transmit pre-compensation assistance data to a reference user equipment. Apparatus 20 may also be controlled by memory 24 and processor 22 to receive, from the reference user equipment, an indication indicating a mapping of a signal transmission that has been pre-compensated to a network element based on the pre-compensation assistance data. Apparatus 20 may further be controlled by memory 24 and processor 22 to transmit, to the network element, an indication of the signal transmission resource that that has been precompensated. In addition, apparatus 20 may be controlled by memory 24 and processor 22 to receive a carrier phase report from the network element based on the indication.

[0083] In some example embodiments, an apparatus (e.g., apparatus 10 and/or apparatus 20) may include means for performing a method, a process, or any of the variants discussed herein. Examples of the means may include one or more processors, memory, controllers, transmitters, receivers, and/or computer program code for causing the performance of the operations.

[0084] Certain example embodiments may be directed to an apparatus that includes means for performing any of the methods described herein including, for example, means for receiving pre-compensation assistance data from a first network element. The apparatus may also include means for determining pre-compensating phase center offset applied for transmission of reference signals per second network element based on at least the precompensation assistance data. The apparatus may further include means for transmitting, to the first network element, an indication indicating a mapping of the signal transmission that has been pre-compensated to the second network element.

[0085] Certain example embodiments may also be directed to an apparatus that includes means for receiving, from a network element, a pre-compensated mapping comprising an indication of a signal transmission resource that has been pre-compensated. The apparatus may also include means for receiving a signal transmission from a reference user equipment, and a signal transmission from a target user equipment. The apparatus may further include means for measuring a carrier phase position based on the pre-compensated mapping, the signal transmission from the reference user equipment, and the signal transmission from the target user equipment. In addition, the apparatus may include means for reporting the carrier phase position to the network element.

[0086] Certain example embodiments may further be directed to an apparatus that includes means for transmitting pre-compensation assistance data to a reference user equipment. The apparatus may also include means for receiving, from the reference user equipment, an indication indicating a mapping of a signal transmission that has been pre-compensated to a network element based on the pre-compensation assistance data. The apparatus may further include means for transmitting, to the network element, an indication of the signal transmission resource that that has been pre-compensated. In addition, the apparatus may include means for receiving a carrier phase report from the network element based on the indication.

[0087] Certain example embodiments described herein provide several technical improvements, enhancements, and /or advantages. For instance, in some example embodiments, it may be possible to provide a method for pre-compensation by a PRU as part of UL CP positioning. As such, certain example embodiments may lower signaling overhead, and reduce PRU power consumption. In other example embodiments, it may be possible to improve the accuracy of the location estimation.

[0088] A computer program product may include one or more computer-executable components which, when the program is run, are configured to carry out some example embodiments. The one or more computer-executable components may be at least one software code or portions of it. Modifications and configurations required for implementing functionality of certain example embodiments may be performed as routine(s), which may be implemented as added or updated software routine(s). Software routine(s) may be downloaded into the apparatus.

[0089] As an example, software or a computer program code or portions of it may be in a source code form, object code form, or in some intermediate form, and it may be stored in some sort of carrier, distribution medium, or computer readable medium, which may be any entity or device capable of carrying the program. Such carriers may include a record medium, computer memory, read-only memory, photoelectrical and/or electrical carrier signal, telecommunications signal, and software distribution package, for example. Depending on the processing power needed, the computer program may be executed in a single electronic digital computer or it may be distributed amongst a number of computers. The computer readable medium or computer readable storage medium may be a non- transitory medium.

[0090] In other example embodiments, the functionality may be performed by hardware or circuitry included in an apparatus (e.g., apparatus 10 or apparatus 20), for example through the use of an application specific integrated circuit (ASIC), a programmable gate array (PGA), a field programmable gate array (FPGA), or any other combination of hardware and software. In yet another example embodiment, the functionality may be implemented as a signal, a non-tangible means that can be carried by an electromagnetic signal downloaded from the Internet or other network.

[0091] According to certain example embodiments, an apparatus, such as a node, device, or a corresponding component, may be configured as circuitry, a computer or a microprocessor, such as single-chip computer element, or as a chipset, including at least a memory for providing storage capacity used for arithmetic operation and an operation processor for executing the arithmetic operation.

[0092] One having ordinary skill in the art will readily understand that the disclosure as discussed above may be practiced with procedures in a different order, and/or with hardware elements in configurations which are different than those which are disclosed. Therefore, although the disclosure has been described based upon these example embodiments, it would be apparent to those of skill in the art that certain modifications, variations, and alternative constructions would be apparent, while remaining within the spirit and scope of example embodiments. Although the above embodiments refer to 5G NR and LTE technology, the above embodiments may also apply to any other present or future 3GPP technology, such as

LTE-advanced, and/or fourth generation (4G) technology.

[0093] Partial Glossary:

[0094] 3GPP 3rd Generation Partnership Project

[0095] 5G 5th Generation

[0096] 5GCN 5G Core Network

[0097] 5GS 5G System

[0098] BS Base Station

[0099] CP Carrier Phase

[0100] DL Downlink

[0101] eNB Enhanced Node B [0102] E-UTRAN Evolved UTRAN

[0103] FR Frequency Range

[0104] gNB 5G or Next Generation NodeB

[0105] LMF Location Management Function

[0106] LTE Fong Term Evolution

[0107] NR New Radio

[0108] NW Network

[0109] PCO Phase Center Offset

[0110] PRU Positioning Reference Unit

[0111] RRC Radio Resource Control

[0112] RSRP Reference Signal Received Power

[0113] Rx Receive

[0114] SRS Sounding Reference Signal

[0115] TEG Timing Error Group

[0116] ToA Time of Arrival

[0117] ToD Time of Departure

[0118] TRP Transmit Reception Point

[0119] Tx Transmit

[0120] UE User Equipment

[0121] UL Uplink

Claims

WE CLAIM:

1. A method comprising: receiving pre-compensation assistance data from a first network element; determining pre-compensating phase center offset applied for transmission of reference signals per second network element based on at least the pre-compensation assistance data; and transmitting, to the first network element, an indication indicating a mapping of the signal transmission that has been pre-compensated.

2. The method according to claim 1, wherein the pre-compensation of the phase center offset is performed using at least one or more of the following: location information of a reference user equipment, orientation information of the reference user equipment, a beam direction of the reference user equipment, or a beam beamwidth of the reference user equipment.

3. The method according to claims 1 or 2, wherein the pre-compensation assistance data comprises at least one of a location of the second network element or an identification of the second network element.

4. The method according to any of claims 1-3, wherein the pre-compensating the phase center offset for the second network element comprises: pre-compensating the phase center offset for one second network element per reference signal resource; pre-compensating the phase center offset for one second network element per reference signal transmission occasion; or pre-compensating the phase center offset for one second network element per reference signal transmission repetition.

5. The method according to any of claims 1-4, wherein when the phase center offset is pre-compensated for the one second network element per reference signal resource, the method further comprises: receiving a configuration with spatial relation information for each signal transmission resource, and the identification of the second network element.

6. The method according to any of claims 1-4, wherein when the phase center offset is pre-compensated for the one second network element per reference signal resource, the method further comprises: receiving channel coherency information for the second network element to assist with the pre-compensation.

7. The method according to any of claims 1-4, wherein pre-compensating the phase center offset for one second network element per reference signal transmission occasion comprises: pre-compensating for a plurality of second network elements, one second network element in each instance of a plurality of instances.

8. The method according to any of claims 1-4, wherein when the phase-center offset is pre-compensated for the one second network element per reference signal transmission repetition, the signal transmission comprises a repetition factor with a time gap of a predefined number of slots.

9. The method according to any of claims 1-8, further comprising: updating pre-compensation information when a location change of a reference user equipment exceeds a threshold value.

10. The method according to any of claims 1-9, further comprising: pre-compensating the phase center offset for a predetermined duration of time based on a fixed offset.

11. A method, comprising : receiving, from a network element, a pre-compensated mapping comprising an indication of a signal transmission resource that has been pre-compensated; receiving a signal transmission from a reference user equipment, and a signal transmission from a target user equipment; measuring a carrier phase based on the pre-compensated mapping, the signal transmission from the reference user equipment, and the signal transmission from the target user equipment; and reporting the carrier phase to the network element.

12. The method according to claim 11 , wherein the carrier phase is at least one of a nondifference carrier phase, a single differenced carrier phase, or a doubled differenced carrier phase.

13. The method according to claims 11 or 12, further comprising: obtaining measurements of the signal transmission from the reference user equipment, and the signal transmission from the target user equipment.

14. The method according any of claims 11-13, further comprising: filtering the measurements based on time stamps on measurement occasions for the network element.

15. A method, comprising: transmitting pre-compensation assistance data to a reference user equipment; receiving, from the reference user equipment, an indication indicating a mapping of a signal transmission that has been pre-compensated to a network element based on the precompensation assistance data; transmitting, to the network element, an indication of the signal transmission resource that that has been pre-compensated; and receiving a carrier phase report from the network element based on the indication.

16. The method according to claim 15, wherein the pre-compensation assistance data comprises a location or an identification of network element to be used for an uplink carrier phase session of a target user equipment.

17. The method according to claims 15 or 16, further comprising: coordinating the mapping to the reference user equipment to enable a target user equipment to use same time instances to perform transmission to the target user equipment.

18. The method according to any of claims 15-17, further comprising: configuring a criterion so that the reference user equipment reports or updates pre- compensation information.

19. An apparatus, comprising: at least one processor; and at least one memory including computer program code, the at least one memory and the computer program code configured to, with storing instructions that, when executed by the at least one processor, cause the apparatus at least to: receive pre-compensation assistance data from a first network element; determine pre-compensating phase center offset applied for transmission of reference signals per second network element based on at least the pre-compensation assistance data; and transmit, to the first network element, an indication indicating a mapping of the signal transmission that has been pre-compensated.

20. The apparatus, according to claim 19, wherein the pre-compensation of the phase center offset is performed using at least one or more of the following: location information of the apparatus, orientation information of the apparatus, a beam direction of the apparatus, or a beam beamwidth of the apparatus.

21. The apparatus according to claims 19 or 20, wherein the pre-compensation assistance data comprises at least one of a location of the second network element or an identification of the second network element.

22. The apparatus according to any of claims 19-21, when pre-compensating the phase center offset for the second network element, the at least one memory and the computer program code are further configured to, with storing instructions that, when executed by the at least one processor, cause the apparatus at least to: pre-compensate the phase center offset for one second network element per reference signal resource; pre- compensate the phase center offset for one second network element per reference signal transmission occasion; or pre- compensate the phase center offset for one second network element per reference signal transmission repetition.

23. The apparatus according to any of claims 19-22, wherein when the phase center offset is pre-compensated for the one second network element per reference signal resource, the at least one memory and the computer program code are further configured to, with storing instructions that, when executed by the at least one processor, cause the apparatus at least to: receive a configuration with spatial relation information for each signal transmission resource, and the identification of the second network element.

24. The apparatus according to any of claims 19-22, wherein when the phase center offset is pre-compensated for the one second network element per reference signal resource, the at least one memory and the computer program code are further configured to, with storing instructions that, when executed by the at least one processor, cause the apparatus at least to: receive channel coherency information for the second network element to assist with the pre-compensation.

25. The apparatus according to any of claims 19-22, wherein when pre-compensating the phase center offset for one second network element per reference signal transmission occasion, the at least one memory and the computer program code are further configured to, with storing instructions that, when executed by the at least one processor, cause the apparatus at least to: pre-compensate for a plurality of second network elements, one second network element in each instance of a plurality of instances.

26. The apparatus according to any of claims 19-22, wherein when the phase-center offset is pre-compensated for the one second network element per reference signal transmission repetition, the signal transmission comprises a repetition factor with a time gap of a predefined number of slots.

27. The apparatus according to any of claims 19-26, wherein the at least one memory and the computer program code are further configured to, with storing instructions that, when executed by the at least one processor, cause the apparatus at least to: update pre-compensation information when a location change of the apparatus exceeds a threshold value.

28. The apparatus according to any of claims 19-27, wherein the at least one memory and the computer program code are further configured to, with storing instructions that, when executed by the at least one processor, cause the apparatus at least to: pre-compensate the phase center offset for a predetermined duration of time based on a fixed offset.

29. An apparatus, comprising: at least one processor; and at least one memory including computer program code, the at least one memory and the computer program code configured to, with storing instructions that, when executed by the at least one processor, cause the apparatus at least to: receive, from a network element, a pre-compensated mapping comprising an indication of a signal transmission resource that has been pre-compensated; receive a signal transmission from a reference user equipment, and a signal transmission from a target user equipment; measure a carrier phase based on the pre-compensated mapping, the signal transmission from the reference user equipment, and the signal transmission from the target user equipment; and report the carrier phase to the network element.

30. The apparatus, according to claim 29, wherein the carrier phase is at least one of a non-difference carrier phase, a single differenced carrier phase, or a doubled differenced carrier phase.

31. The apparatus according to claims 29 or 30, wherein the at least one memory and the computer program code are further configured to, with storing instructions that, when executed by the at least one processor, cause the apparatus at least to: obtain measurements of the signal transmission from the reference user equipment, and the signal transmission from the target user equipment.

32. The apparatus according to any of claims 29-31, wherein the at least one memory and the computer program code are further configured to, with storing instructions that, when executed by the at least one processor, cause the apparatus at least to: filter the measurements based on time stamps on measurement occasions for the network element.

33. An apparatus, comprising: at least one processor; and at least one memory including computer program code, the at least one memory and the computer program code configured to, with storing instructions that, when executed by the at least one processor, cause the apparatus at least to: transmit pre-compensation assistance data to a reference user equipment; receive, from the reference user equipment, an indication indicating a mapping of a signal transmission that has been pre-compensated to a network element based on the precompensation assistance data; transmit, to the network element, an indication of the signal transmission resource that that has been pre-compensated; and receive a carrier phase report from the network element based on the indication.

34. The apparatus according to claim 33, wherein the pre-compensation assistance data comprises a location or an identification of network element to be used for an uplink carrier phase session of a target user equipment.

35. The apparatus according to claims 33 or 34, wherein the at least one memory and the computer program code are further configured to, with storing instructions that, when executed by the at least one processor, cause the apparatus at least to: coordinate the mapping to the reference user equipment to enable a target user equipment to use same time instances to perform transmission to the target user equipment.

36. The apparatus according to any of claims 33-35, wherein the at least one memory and the computer program code are further configured to, with storing instructions that, when executed by the at least one processor, cause the apparatus at least to: configure a criterion so that the reference user equipment reports or updates precompensation information.

37. An apparatus, comprising: means for receiving pre-compensation assistance data from a first network element; means for determining pre-compensating phase center offset applied for transmission of reference signals per second network element based on at least the precompensation assistance data; and means for transmitting, to the first network element, an indication indicating a mapping of the signal transmission that has been pre-compensated.

38. The apparatus according to claim 37, wherein the pre-compensation of the phase center offset is performed using at least one or more of the following: location information of the apparatus, orientation information of the apparatus, a beam direction of the apparatus, or a beam beamwidth of the apparatus.

39. The apparatus according to claims 37 or 38, wherein the pre-compensation assistance data comprises at least one of a location of the second network element or an identification of the second network element.

40. The apparatus according to any of claims 37-39, wherein the pre-compensating the phase center offset for the second network element comprises: pre-compensating the phase center offset for one second network element per reference signal resource; pre-compensating the phase center offset for one second network element per reference signal transmission occasion; or pre-compensating the phase center offset for one second network element per reference signal transmission repetition.

41. The apparatus according to any of claims 37-40, wherein when the phase center offset is pre-compensated for the one second network element per reference signal resource, the apparatus further comprises: means for receiving a configuration with spatial relation information for each signal transmission resource, and the identification of the second network element.

42. The apparatus according to any of claims 37-40, wherein when the phase center offset is pre-compensated for the one second network element per reference signal resource, the apparatus further comprises: means for receiving channel coherency information for the second network element to assist with the pre-compensation.

43. The apparatus according to any of claims 37-40, wherein pre-compensating the phase center offset for one second network element per reference signal transmission occasion comprises: pre-compensating for a plurality of second network elements, one second network element in each instance of a plurality of instances.

44. The apparatus according to any of claims 37-40, wherein when the phase-center offset is pre-compensated for the one second network element per reference signal transmission repetition, the signal transmission comprises a repetition factor with a time gap of a predefined number of slots.

45. The apparatus according to any of claims 37-44, further comprising: means for updating pre-compensation information when a location change of the apparatus exceeds a threshold value.

46. The apparatus according to any of claims 37-45, further comprising: means for pre-compensating the phase center offset for a predetermined duration of time based on a fixed offset.

47. An apparatus, comprising: means for receiving, from a network element, a pre -compensated mapping comprising an indication of a signal transmission resource that has been pre-compensated; means for receiving a signal transmission from a reference user equipment, and a signal transmission from a target user equipment; means for measuring a carrier phase based on the pre-compensated mapping, the signal transmission from the reference user equipment, and the signal transmission from the target user equipment; and means for reporting the carrier phase to the network element.

48. The apparatus according to claim 47, wherein the carrier phase is at least one of a non-difference carrier phase, a single differenced carrier phase, or a doubled differenced carrier phase.

49. The apparatus according to claims 47 or 48, further comprising: means for obtaining measurements of the signal transmission from the reference user equipment, and the signal transmission from the target user equipment.

50. The apparatus according to any of claims 47-49, further comprising: means for filtering the measurements based on time stamps on measurement occasions for the network element.

51. An apparatus, comprising: means for transmitting pre-compensation assistance data to a reference user equipment; means for receiving, from the reference user equipment, an indication indicating a mapping of a signal transmission that has been pre-compensated to a network element based on the pre-compensation assistance data; means for transmitting, to the network element, an indication of the signal transmission resource that that has been pre-compensated; and means for receiving a carrier phase report from the network element based on the indication.

52. The apparatus according to claim 51, wherein the pre-compensation assistance data comprises a location or an identification of network element to be used for an uplink carrier phase session of a target user equipment.

53. The apparatus according to claims 51 or 52, further comprising: means for coordinating the mapping to the reference user equipment to enable a target user equipment to use same time instances to perform transmission to the target user equipment.

54. The apparatus according to any of claims 51-53, further comprising: means for configuring a criterion so that the reference user equipment reports or updates pre-compensation information.

55. A non-transitory computer readable medium comprising program instructions stored thereon for performing the method according to any of claims 1-18.

56. An apparatus comprising circuitry configured to cause the apparatus to perform a process according to any of claims 1-18.