TECHNICAL FIELD

The present disclosure relates to the field of angle-based localization, positioning, sensing and ranging and how to improve said technology to increase accuracy of determining of a location of a user device.

BACKGROUND

Localization (which also may be referred to as positioning, sensing, or ranging) is an important enabling technology for next generation wireless networks. Localization in particular refers to technologies of retrieving information about a position or direction of an object from measurements of emitted or reflected signals. Information of interest for localization are position, distance, range, direction, motion, shape, orientation, or velocity, etc.

Presently, angle-based approaches are used for high-resolution localization due to their ability to distinguish and localize objects with small details and resolution. For instance, in the LoCation Service (LCS) provided in Long Term Evolution (LTE) and New Radio (NR), Ao A (Angle-of-arrival) and AoD (Angle-or-Departure) methods are considered to be supported for downlink (DL), uplink (UL) and sidelink (SL). An illustration of DL-AoD positioning in 5G- NR is given in FIG. 17, in which base station transmission and reception points (e.g. BSs, TPRs, gNB, or eNB) are transmitting DL positioning reference signals (PRSs) to a user equipment (UE) and the UE performs angle-based measurement (e.g., DL-PRS-RSRP) of the received signals using assistance data received from a location server.

The resulting measurements can be used along with positioning assistance data, positioning configuration information, and other measurements to locate the UE. Similarly, the UL-AoA method in 5G-NR makes use of angle-based measurement (e.g., measured azimuth angle and/or zenith angle such as AoA) at multiple BSs or TRPs of uplink signals transmitted from the UE.

Using assistance data received from a location server along with other configuration information and resulting measurements, the location of UE is estimated. AoA/AoD measurements can also be used e.g., for SL positioning or for positioning using a high- frequency band such as a mm wave or a (sub-)THz wave band.

To obtain the localization information, multiple angle-based or other measurements are usually needed. More measurements are in general favorable for reliable estimation, e.g., given multiple reliable angle-based measurements are obtained with stable or known orientations.

Therefore, challenges for angle-based localization are that multiple angle-based measurements can be subject to unknown and unstable errors: e.g., a calibration error of antenna arrays or panels; or unknown or imperfect local coordinates due to orientation change or movement. Combining multiple measurements with such unknown knowledge may lead to the degradation of localization. Such effects are in particular relevant for sidelink localization or Uu-localization with non-static entities such as an unmanned aerial vehicle (UAV), a moving UE, or a NonTerrestrial Network.

The above-mentioned calibration errors, or shifts of local coordinates, may exist in the following settings:

- Multiple angle-based measurements (e.g., AoA, AoD, RSRP, RSRQ, RSSI, SINR or CQI) are subject to antenna calibration errors (e.g., error of antenna reference point (ARP), or phase shift by each antenna element).

- Angle-based measurements based on Doppler frequency or applied in antenna switching systems are subject to unstable velocity or orientation or antenna calibration error.

- Different calibration errors of antenna arrays might be present for multiple panels either in the transmitter or receiver.

- Real-time orientation or velocity, antenna configuration, or antenna calibration error are difficult to be obtained or be shared, in particular because of privacy issues.

FIG. 18 exemplifies the challenges which are introduced by the orientation changes for SL- AoA or SL-AoD localization. The solid arrow and dashed arrow in FIG. 18 show the direction of transmitting SL-PRS. In the left part, Alphal and Alpha2 are an AoA estimate based on local coordinates of the corresponding car. In the right part, Alphal and Alpha2 are an AoD estimate based on local coordinates of the corresponding car. Assuming that a location server is not aware of the orientation change occurrence (phi 1 -> 2) between two local coordinates which are associated with two PRS transmissions (e.g., transmitting SL-PRS 1 and SL-PRS2), the location estimate is erroneous if calculated at a location server due to such orientation unstableness.

That is, in radio-access technology (RAT)-based positioning methods in LTE and 5G-NR, the unknown imperfect calibration for antenna arrays or panels, or unknown imperfect knowledge of local/global coordinates has not been considered in localization methods. Basically, conventional methods assume that phase shifts of antenna arrays are calibrated and that there are no residential errors, as well as stable local or global coordinates during localization instances. Therefore, the conventional angle-based methods are subject to accuracy degradation as described above.

A conventional approach to mitigate accuracy degradation is to share real-time information from sensors (e.g., using motion sensors such as an inertial measurement unit, an accelerometer, or a gyroscope) or a real-time antenna calibration error to increase the accuracy of angle-based localization. However, several drawbacks exist for this approach: firstly, this approach might be able to compensate the orientation changes during the motion but only at the expense of larger sensor information sharing to guarantee real-time error compensation; secondly, UEs are not willing to exposure their sensor information or antenna configuration to other UEs due to privacy issues.

Therefore, there is the need to enhance the angle-based localization which is subject to unknown imperfect calibration of antenna arrays or panels, or unknown imperfect knowledge of coordinates or sensor information.

SUMMARY

In view of the above-mentioned problem, an objective of embodiments of the present disclosure is to enhance the accuracy of angle-based localization. This objective is in particular achieved by proposing the concept of angle-based error groups (AEGs), as well as its association and signaling procedures. This concept can in particular be applied to wireless communication systems.

This or other objectives may be achieved by embodiments of the present disclosure as described in the enclosed independent claims. Advantageous implementations of embodiments of the present disclosure are further defined in the dependent claims. A first aspect of the present disclosure provides a wireless device for localization, wherein the wireless device is configured to: obtain a first reference signal; obtain a second reference signal; and determine an angle-based error group, AEG, based on the first reference signal and the second reference signal; wherein the AEG indicates that an angle-based error difference between the first reference signal and the second reference signal within the AEG is below a predefined threshold.

This ensures that angle-based errors can be taken into consideration for localization purposes. The AEG allows for indicating that a first and a second reference signal are subject to a predefined angle-based error, which can be considered for localization. This is further beneficial as exclusively using real-time sensor information and/or real-time antenna calibration information for improving the accuracy of angle-based localization can be avoided.

In particular, localization includes angle-based localization. In particular, angle-based localization includes at least one of angle-based positioning, angle-based sensing and anglebased ranging. In particular, angle-based localization relies on angle-based measurement. In particular, angle-based measurement includes at least on of AoA, AoD, Differential AoA, Differential AoD, RSRP, RSRQ, RS SI, SINR, CQI.

In particular, the wireless device is configured to not exclusively rely on using real-time sensor information and/or real-time antenna calibration information for improving the accuracy of angle-based localization. In particular, the concept of AEGs can be used independently of said real time information, but also in combination with said real time information.

This is beneficial as it increases privacy of the wireless device since less information is exposed and reduces signalling overhead for exchanging real-time motion sensor information and/or real-time antenna calibration information.

In particular, the real-time sensor information comprises real-time motion sensor information. In particular, the real-time motion sensor information comprises information obtained by at least one of measurements from inertial measurement unit such as a body’s specific force, angular rate, orientation, acceleration measurement, gyroscope measurement, magnetometers measurements. In particular, to avoid means to not exclusively use real-time sensor information and/or realtime antenna calibration information for improving the accuracy of angle-based localization at all.

In other words, if the first reference signal and the second reference signal are associated with the same AEG, an angle-based error difference between the first reference signal and the second reference signal is below a predefined threshold.

In particular, the predefined threshold can be configured, e.g. by an external entity or network entity or another wireless device.

In an implementation form of the first aspect, the wireless device is further configured to use the AEG or AEG related information for determining the location of a user device.

This ensures that the AEG can be used to increase accuracy of determining the location of a user device.

In particular, the wireless device can be configured to determine the location of the user device based on the AEG. In particular, the wireless device can be configured to transmit the AEG and/or AEG related information to another device for determining the location of the user device based on the AEG and/or the AEG related information. In this case, it is the other device which performs the determining of the location.

In a further implementation form of the first aspect, the angle-based error results from at least one of phase calibration between antenna elements of an antenna array; phase offset with respect to an antenna reference point; orientation offset; polarization offset; motion sensor offset; angular acceleration offset.

This ensures that errors resulting from calibration of an antenna array, orientation offset, polarization offset, motion sensing, angular acceleration can be effectively detected.

In particular, the angle-based error affects localization accuracy of the wireless device. In particular, motion sensor offset comprises offset of an acceleration sensor or a velocity sensor.

In a further implementation form of the first aspect, the wireless device is further configured to perform at least one of transmit the first reference signal and/or receive the first reference signal to obtain the first reference signal; transmit the second reference signal and/or receive the second reference signal to obtain the second reference signal.

This provides various ways of obtaining the respective reference signal.

In particular, a transmitted reference signal is called a TX reference signal. In particular, a received reference signal is called an RX reference signal.

In particular, an angle-based error which is determined at the transmitter side is called TX AE. In other words, the TX reference signal is associated with the AE. In particular, an angle-based error which is determined at the receiver side is called RX AE. In other words, the RX reference signal is associated with the AE. In particular, an angle-based error at the receiver side is associated with one or more measurements based on one or more RX reference signals.

In a further implementation form of the first aspect, the wireless device is further configured to obtain a first measurement based on one or more reference signals, and obtain a second measurement based on one or more reference signals.

In particular, the two groups of one or more reference signals are the same, partly overlap, or are different from each other.

In a further implementation form of the first aspect, the wireless device is further configured to associate the AEG with the first measurement and/or the second measurement.

This is beneficial, as association of the AEG and the first or second measurement allows a network device or a user device to use this formation to combine measurement results effectively (by means of the association information) to improve angle accuracy (that is, localization accuracy). In a further implementation form of the first aspect, the wireless device is further configured to transmit AEG related information to another device.

This ensures that the other device can use the AEG related information to increase accuracy of localization of a user device.

In particular, the other device comprises at least one of: a UE, a RAN entity, a location server, a sensing server. In particular, the location server may be comprised by a UE or a RAN entity. In particular, the sensing server may be comprised by a UE or a RAN entity.

In a further implementation form of the first aspect, the AEG related information is used to indicate the AEG to the other device.

This ensure that the other device knows about the AEG to which the first and second reference signals belong and may use it for increasing accuracy of localization accordingly.

In particular, the AEG related information comprises the AEG.

In a further implementation form of the first aspect, the wireless device is further configured to perform at least one of: obtain a request and transmit the AEG related information based on the request; obtain a request including configuration information how to determine the AEG, and determine the AEG based on the request; obtain a request including configuration information how to transmit the AEG related information, and transmit of AEG related information based on the request.

This ensures that the AEG and/or AEG related information can be requested from another device.

In particular, the wireless device can be configured to configure the predefined threshold based on the request. The predefine threshold can be selected from multiple pre-stored thresholds. In particular, the threshold may or may not be signalled in a request. The wireless device could be pre-configured with multiple thresholds and then select one by itself and report it with AEG related information. The threshold can also be signalled to wireless device by configuration AEG settings. In a further implementation form of the first aspect, the wireless device is further configured to transmit the AEG related information to the other device using at least one of: Radio Resource Control (RRC) signalling, Location Positioning Protocol (LPP), NR Positioning Protocol A (NRPPa), signalling for sensing and/or ranging.

This ensures that the AEG related information or the AEG can be effectively signalled to the other device.

In a further implementation form of the first aspect, the AEG related information further comprises at least one of: an AEG identifier, ID; an AEG class; an association of an AEG with one or more reference signals; an association of an AEG with one or more measurements.

This provides various ways of indicating a grouping AEG related information.

In particular, an AEG can be associated with at least two reference signals or with at least two measurements. In particular, the reference signals are provided by reference signal resources.

In particular, the AEG indicator indicates at least one of: whether the wireless device is a UE entity or a RAN entity; whether the wireless device is a TX entity, a RX entity or a TX/RX entity.

In particular, the AEG class comprises at least one of: a class id, a number of AEGs per class, an AEG ID.

In a further implementation form of the first aspect, the wireless device comprises at least one of: a user equipment, UE, a radio access network, RAN, entity.

In particular, the RAN entity comprises at least one of: base station, BS, transmit and receive point, TRP, eNB, gNB.

A second aspect of the present disclosure provides a device for angle-based localization, wherein the device is configured to: receive, from a wireless device, angle-based error group, AEG, related information corresponding to measurements based on one or more reference signals, and determine the position of a user device based on the measurement and the AEG related information.

In particular, the AEG indicates that an angle-based error difference based on first measurement and second measurement within the AEG is below a predefined threshold.

This ensures that the AEG related information may be used in devices other than the wireless device to increase accuracy of localization.

In particular, if the wireless device is a UE, the device may be at least one of: a RAN entity, a location server, a sensing server, a UE. In particular, if the wireless device is a RAN entity, the device may be at least one of: a UE, a location server, a sensing server,

In particular, the AEG related information comprises the AEG.

A third aspect of the present disclosure provides a method for localization, the method comprising the steps of: obtaining, by a wireless device, a first reference signal; obtaining, by the wireless device, a second reference signal; and determining, by the wireless device, an angle-based error group, AEG, based on the first reference signal and the second reference signal; wherein the AEG indicates that an angle-based error difference between the first reference signal and the second reference signal within the AEG is below a predefined threshold.

In an implementation form of the third aspect, the method further comprises using, by the wireless device, the AEG or AEG related information for determining the location of a user device.

In a further implementation form of the third aspect, the angle-based error results from at least one of: phase calibration between antenna elements of an antenna array; phase offset with respect to an antenna reference point; orientation offset; polarization offset; motion sensor offset; angular acceleration offset.

In a further implementation form of the third aspect, the method further comprises performing, by the wireless device, at least one of: transmitting the first reference signal and/or receiving the first reference signal to obtain the first reference signal; transmitting the second reference signal and/or receiving the second reference signal to obtain the second reference signal.

In a further implementation form of the third aspect, the method further comprises obtaining, by the wireless device, a first measurement based on one or more reference signals, and obtaining, by the wireless device, a second measurement based on one or more reference signals.

In a further implementation form of the third aspect, the method further comprises associating, by the wireless device, the AEG with the first measurement and/or the second measurement.

In a further implementation form of the third aspect, the method further comprises transmitting, by the wireless device, AEG related information to another device.

In a further implementation form of the third aspect, the AEG related information is used to indicate the AEG to the other device.

In a further implementation form of the third aspect, the method further comprises at least one of obtaining, by the wireless device, a request and transmitting, by the wireless device, the AEG related information based on the request; obtaining, by the wireless device, a request including configuration information how to determine the AEG, and determining, by the wireless device, the AEG based on the request; obtaining, by the wireless device, a request including configuration information how to transmit the AEG related information, and transmitting, by the wireless device, of AEG related information based on the request.

In a further implementation form of the third aspect, the method further comprises transmitting, by the wireless device, the AEG related information to the other device using at least one of Radio Resource Control (RRC) signalling, Location Positioning Protocol (LPP), NR Positioning Protocol A (NRPPa), signalling for sensing and/or ranging.

In a further implementation form of the third aspect, the AEG related information further comprises at least one of an AEG identifier, ID; an AEG class; an association of an AEG with one or more reference signals; an association of an AEG with one or more measurements. In a further implementation form of the third aspect, the wireless device comprises at least one of a user equipment, UE, a radio access network, RAN, entity.

The third aspect and its implementation forms include the same advantages as the first aspect and its respective implementation forms.

A fourth aspect of the present disclosure provides a method for angle-based localization, wherein the method comprises the steps of receiving, by a device, from a wireless device, angle-based error group, AEG, related information corresponding to measurements based on one or more reference signals, and determining, by the device, the position of a user device based on the measurement and the AEG related information.

The fourth aspect and its implementation forms include the same advantages as the second aspect and its respective implementation forms.

A fifth aspect of the present disclosure provides a computer program comprising instructions which, when the program is executed by a computer, cause the computer to perform the method according to the third or fourth aspect or any of its implementation forms.

A sixth aspect of this disclosure provides a storage medium storing executable program code which, when executed by a processor, causes the method according to the third or fourth aspect or any of its implementation forms to be performed.

It has to be noted that all devices, elements, units and means described in the present application could be implemented in the software or hardware elements or any kind of combination thereof. All steps which are performed by the various entities described in the present application as well as the functionalities described to be performed by the various entities are intended to mean that the respective entity is adapted to or configured to perform the respective steps and functionalities. Even if, in the following description of specific embodiments, a specific functionality or step to be performed by external entities is not reflected in the description of a specific detailed element of that entity which performs that specific step or functionality, it should be clear for a skilled person that these methods and functionalities can be implemented in respective software or hardware elements, or any kind of combination thereof. BRIEF DESCRIPTION OF DRAWINGS

The above-described aspects and implementation forms of the present disclosure will be explained in the following description of specific embodiments in relation to the enclosed drawings, in which

FIG. 1 shows a schematic view of a wireless device according to an embodiment of the present disclosure;

FIG. 2 shows a schematic view of a wireless device according to an embodiment of the present disclosure in more detail;

FIG. 3 shows a schematic view of a device according to an embodiment of the present disclosure;

FIG. 4 shows a schematic view of an operating scenario according to the present disclosure;

FIG. 5 shows a schematic view of AEG classes according to the present disclosure;

FIG. 6 shows a schematic view of AEG signaling according to the present disclosure;

FIG. 7 shows another schematic view of AEG signaling according to the present disclosure;

FIG. 8 shows another schematic view of AEG signaling according to the present disclosure; FIG. 9 shows a schematic view of an operating scenario according to the present disclosure; FIG. 10 shows another schematic view of AEG signaling according to the present disclosure; FIG. 11 shows another schematic view of AEG signaling according to the present disclosure; FIG. 12 shows another schematic view of AEG signaling according to the present disclosure;

FIG. 13 shows another schematic view of AEG signaling according to the present disclosure; FIG. 14 shows another schematic view of AEG signaling according to the present disclosure; FIG. 15 shows another schematic view of AEG signaling according to the present disclosure; FIG. 16 shows a schematic view of a method according to an embodiment of the present disclosure;

FIG. 17 shows a schematic view of a conventional DL-AoD Positioning; and

FIG. 18 shows a schematic view of a conventional localization.

DETAILED DESCRIPTION OF EMBODIMENTS

FIG. 1 shows a schematic view of a wireless device 100. The wireless device 100 is for localization, in particular for angle-based localization. By determining an angle-based error group (AEG) 103, the wireless device 100 enables improving accuracy of localization, e.g. of a user device. The wireless device 100 for example can be a UE entity, or part of a UE entity. The wireless device 100 may also be or be part of a radio access network (RAN) entity, e.g., a BS, a TRP, an eNB, or a gNB. In the following text, BS, TRP, eNB, or gNB are used interchangeably to indicate the entity in radio access network.

To resolve the AEG 103, the wireless device 100 obtains a first reference signal 101 and a second reference signal 102. The first reference signal 101 and/or the second reference signal 102 may be at least one of a positioning reference signal PRS; a sounding reference signal SRS; another reference signal used for positioning, sensing, or ranging.

Then, based on the first reference signal 101 and the second reference signal 102, the AEG 103 is determined. The AEG 103 indicates that an angle-based error (AE) difference between the first reference signal 101 and the second reference signal 102 is below a predefined threshold. That is the first reference signal 101 and the second reference signal 102 are within the AEG 103. The threshold can be preconfigured in the device or adjusted automatically and/or upon request.

The AE may result from an error after the calibration of an antenna array (e.g., phase shift, phase center offset (PCO) , antenna reference point (ARP)) or from an un-calibrated antenna array. The AE may further result from an orientation error (e.g., represented by Euler angle or Quaternion) after orientation offset compensation with respect to local or global coordinates or with uncompensated orientation offset. The AE may further result from a polarization offset before or after antenna array calibration. The AE may further result from a motion sensor error (or an equivalent angle error caused by motion sensor error). A motion sensor error may be a velocity error or an angle offset due to a velocity error before or after sensor calibration or compensation. The AE may further result from an acceleration error, an angular acceleration error, or an angle offset due to acceleration error, before or after the calibration of an acceleration sensor. The AE may be imposed at transmitter (TX) side or receiver (RX) side, depending on whether the error source is at TX or RX entity for the localization function. Therefore, there is a TX angle-error and an RX angle-error, respectively. In other words, the AE may result from at least one of phase calibration between antenna elements of an antenna array; phase offset with respect to an antenna reference point; orientation offset; polarization offset; motion sensor offset; angular acceleration offset.

To mitigate the AE, the AEG 103 may be applied either at a UE entity or a RAN entity (e.g., a BS, a TRP, an eNB, or a gNB). A TX AEG is associated with the transmission of one or more reference signal (RS) resources for DL, UL, or SL localization purpose, in which the difference between TX AEs of any two RS resources associated with the same TX AEG are within a certain threshold. The RS may be a positioning reference signal PRS, a sounding reference signal SRS, or another reference signal used for the purpose of localization. The RS may be the first and/or the second reference signal 101, 102.

An RX AEG is associated with one or more DL, UL, or SL measurements (absolute or differential measurements) for localization, in which the difference between an RX AE of any two DL, UL, or SL measurements associated with the same RX AEG is within a certain threshold. The signals used for the DL, UL, or SL measurements may be the first and/or the second reference signal 101, 102.

An RXTX AEG is associated with one or more RXTX angle-based measurement(s) and/or one or more RS resources for localization, in which the difference(s) of the sum of corresponding TX AE(s) and RX AE(s) between any two RX-TX measurements and/or one or more RS resources associated with the same RXTX AEG are within a certain threshold. The signals used for the RXTX angle-based measurement(s), or the RS resources for localization may be the first and/or the second reference signal 101, 102.

The above mentioned “certain threshold” could be one of multiple configured thresholds (i.e. an interval or margin). Such configuration could be signaled or pre-configured in the TX and/or RX UE.

Once the AEG 103 to which the first and second reference signal 101, 102 belong is known, countermeasures can be performed based on the AEG 103, to improve accuracy of localization.

Optional preliminary steps before AEG determination may include calibration or compensation approaches for antenna arrays to mitigate an angle-based measurement error (e.g., Ao A, AoD, RSRP, RSRQ, RS SI, SNR, SINR, CQI estimation error). The approaches may include at least one of phase shifts between different antenna elements may be calibrated; antenna reference points (ARPs) may be calibrated; phase alignment to reference points may be calibrated; an antenna phase center offset (PCO) with respect to a physical ARP may be calibrated; mutualcoupling between antenna elements may be compensate; receiver mismatch may be compensated; sensor information error from a sensor (e.g. orientation, velocity, acceleration error) may be calibrated.

In view of FIG. 4, an optional and non-limiting example of an RX AEG at a UE entity is explained. Alphal and Alpha2 are two AoA measurements received by the cars in the upper part of the figure (upper left car and upper right car), through signal SL-PRS 1 and signal SL- PRS2. The two upper cars shown in FIG. 4 may be two geometrically-distributed cars or a single car’s snapshots at two time instants. The local coordinates of the upper two cars are given by the solid line and the dashed line. In this example it is assumed that an RX AE of the upper two cars consists of orientation offsets with respect to local coordinates. The difference between the RX AEs associated with these two SL measurements on SL-PRS 1 and SL-PRS2 is solely caused by orientation difference If l<Pi->21 < ( ^or — ) 8, where 6 is a margin, then the RX AEs associated with these two measurements form a UE RX AEG.

Turning back to FIG. 2, the wireless device 100 is now going to be described in more detail. The wireless device 100 of FIG. 2 includes all functions and features of the wireless device 100 as described in view of FIG. 1.

As illustrated in FIG. 2, the wireless device 100 optionally may use the AEG 103 for determining the location of a user device 201 (e.g., a UE entity). Therefore, the wireless device 100 may e.g. transmit the AEG 103 or AEG related information 203 to the user device 201 (e.g., a UE entity) or to a network side device (e.g., a RAN entity). In particular, the accuracy of determining the location of a user device 201 can be improved by means of the AEG 103. This may be implemented by using the AEG 103 or the AEG related information in the user device 201 or in a network side device. Although the wireless device 100 and the user device 201 are illustrated as two separate entities in FIG. 2, the wireless device 100 may be the user device 201 or be part of the user device 201. Alternatively, the wireless device 100 may be or may be part of a network side device.

To obtain the first reference signal 101, the wireless device 100 may transmit the first reference signal 101 and/or receive the first reference signal 101. In other words, the wireless device 100 obtains the first reference signal 101 before the signal is transmitted by the wireless device 100, or the wireless device 100 obtains the first reference signal 101 after it is received by the wireless device 100. To obtain the second reference signal 102, the wireless device 100 may transmit the second reference signal 102 and/or receive the second reference signal 102. In other words, the wireless device 100 obtains the second reference signal 102 before the signal is transmitted by the wireless device 100, or the wireless device 100 obtains the second reference signal 102 after it is received by the wireless device 100.

If the wireless device 100 is located at a UE entity, it e.g. may transmit the first or second reference signal 101, 102 to another UE entity or to a RAN entity. If the wireless device 100 is located at a RAN entity, it e.g. may transmit the first or second reference signal 101, 102 to a UE entity or to another RAN entity.

If the wireless device 100 is located at a UE entity, it e.g. may receive the first or second reference signal 101, 102 from another UE entity or from a RAN entity. If the wireless device 100 is located at a RAN entity, it e.g. may receive the first or second reference signal 101, 102 from a UE entity or from another RAN entity.

As shown in FIG. 2, the wireless device 100 optionally may obtain a first measurement 202a based on one or more reference signals and obtain a second measurement 202b based on one or more reference signals. The first measurement 202a and the second measurement 202b may be used to improve localization accuracy, together with the AEG 103.

Further optionally, the first measurement 202a and/or the second measurement 202b may be associated with the AEG 103 by the wireless device 100. The association may be used to effectively combine the AEG 103 and the measurement 202 to improve localization accuracy.

FIG. 2 also shows that the wireless device 100 optionally may transmit AEG related information 203 to another device 204. The AEG related information 203 may be suitable for indicating the AEG to another device 204. That is, the AEG related information 203 may carry the AEG 103 or may carry information for identifying the AEG 103.

Although that the other device 204 and the user device 201 are illustrated as separate entities in FIG. 2, the other device 204 may be the user device 201. In particular, if the wireless device 100 is a UE entity, the AEG related information 203 may be transmitted to another UE entity or to a RAN entity. In particular, if the wireless device 100 is a RAN entity, the AEG related information 203 may be transmitted to another RAN entity or to a UE entity.

Optionally, the wireless device 100 may obtain a request 205 and transmit the AEG related information 203 based on the request. Further optionally, the wireless device 100 may obtain a request 205 including configuration information how to determine the AEG 103, and determine the AEG 103 based on the request. Further optionally, the wireless device 100 may obtain a request 205 including configuration information how to transmit the AEG related information 203, and transmit of AEG related information based on the request 205.

In particular the predefined threshold for assessing whether the first reference signal 101 and the second reference signal 102 belong to a same AEG 103 can be adjusted by means of this request 205. The request may also define how many TX AEG or RX AEG needs to be associated and/or reported.

To indicate the AEG 103 to the other device 204, the AEG related information 203 may further comprises an AEG identifier, ID, an AEG class, an association of an AEG with one or more reference signals or an association of an AEG with one or more measurements.

The AEG ID (which may also be called AEG indicator) e.g. may indicate whether the AEG 103 is at UE entity or at a RAN entity (e.g. a BS, a TRP, an eNB, a gNB), or whether its entity is TX or RX, or acting as TX and RX simultaneously.

The AEG ID may indicate whether the AEG is a UE TX AEG, a BS TX AEG, a UE RX AEG, a BS RX AEG, or a RXTX AEG. The term BS AEG is used to indicate that the AEG is at a RAN entity (e.g. a BS, a TRP, an eNB, a gNB). An entity (UE or RAN) may have multiple AEGs which may be associated with different RS resources or measurements, e.g., for different antenna-array groups or panels. Therefore, the AEG ID may be used to indicate the ID numbering of AEG among different AEGs.

The AEG class may further classify the AEG 103 depending on the type of angle-based error. The use of AEG classes is optional, since the indication of AEG classes are further options of an AEG indicator, while the AEG 103 may be indicated without classification. Examples of AEG classes are given in FIG. 5. In these examples, for one class, the AEG 103 contains the angle-based measurement errors which could come from one or more of the following sources: antenna calibration error, orientation, angular velocity and/or angular acceleration; for another class, the AEG 103 contains the angle-based measurement errors which could come from one or more of the following sources: velocity, acceleration; and for a further class, the AEG 103 contains angle-based measurement errors which comes from polarization offset.

To enable the use of AEG classes, the following parameters may be defined to indicate the AEG classes: a class ID to indicate an AEG class; a number of AEGs per class; an AEG ID (e.g. per class or for all AEGs). In each class, an error source (e.g., antenna calibration error or orientation error) may be further indicated (e.g., error source ID, or bitmap).

An AEG class may be combined with an AEG ID, (i.e., UE/BS RX/TX/RXTX AEG). For example, UE TX AEG(s) plus error sources from Class 1 may be combined.

In addition, the configuration of AEGs 103 (e.g., the number of AEGs (or per class) to report/associate, the AEG ID, the AEG Class ID, or the error source) may be sent via Radio Resource Control (RRC) signaling, a Location Positioning Protocol (LPP), a NR Positioning Protocol A (NRPPa), or new signaling for sensing or ranging (i.e., between sensing/ranging information fusion/inference entity in core network, UE/BS/TRP. For example, NRPPa may be replaced by NG interface for sensing. LPP may be replaced by general interface between UE/entity in core via NG/NAS/RRC). In other words, the wireless device 100 optionally may transmit the AEG related information 203 to the other device 204 using at least one of: Radio Resource Control (RRC) signalling, Location Positioning Protocol (LPP), NR Positioning Protocol A (NRPPa), signalling for sensing and/or ranging.

To enhance the accuracy of positioning and sensing, AEGs are signaled between network entities and UEs to facilitate effective usage of AEG-associated reference signals and/or measurements. The AEG 103 definition is based on AE (determined by network entities/UEs), while the AE is not explicitly shared between network entities and UEs. With regard to the AEG class, it is one (subordinated) option of AEG indication.

FIG. 3 illustrates a device 300 for angle-based localization. The device 300 is configured to receive angle-based error group, AEG, related information 203 from a wireless device 100 (e.g. the wireless device as described in view of figures 1 and 2) corresponding to measurements based on one or more reference signals 301. The device 300 then determines the position of a user device 201 (e.g. the wireless device as described in view of figures 1 and 2) based on the measurements (i.e. the one it performed itself or received from other wireless device) and the AEG related information 203. The measurements associated with the AEG related information

203 can be obtained from an RX device of one or more reference signals 301 (the one or more reference signals 301 may include the first reference signal 101 and the second reference signal 102).

In a further example, the device 300 alternatively or additionally may receive measurements and AEG related information (e.g., association information) to determine the position of the user device 201.

If the wireless device 100 e.g. is a RAN entity, the device 300 can be a UE entity. In this case, the device 300 e.g. can be or can be a part of the other device 204 (not shown in FIG. 3). If the wireless device 100 e.g. is a UE entity, the device 300 can be a RAN entity. In this case, the wireless device 100 e.g. can be or can be a part of the other device 204.

Several signaling procedures to support AEGs 103 are now going to be explained in view of FIG. 6 to FIG. 15. Although in figures 6, 7, 8, 10, 11, 12 and 14 the RAN entity is provided with reference number 204 and the UE entity with the reference number 100, the wireless device 100 can also be assigned to the UE entity and the other device 204 can also be assigned to the RAN entity, and vice versa.

The capabilities of a UE 100 to support AEGs 103 need to be known at the RAN 204 or a location/sensing server. The location server or sensing server (denoted as location/sensing server or location server in the rest of the document), which may be located in core network (RAN) or in a UE, is central for the positioning, sensing, or ranging architecture in networks, and is coordinating and responsible for positioning, sensing, or ranging procedures such as configuration, measurement, assistance data delivery, reference signal transmission, and/or final result estimation.

FIG. 6 shows signaling for requesting and reporting of AEG capabilities of a UE 100. The RAN

204 in the figure can be a BS, a TRP, an eNB, or a gNB. The request signaling in the first step 601 may request a periodic, aperiodic, or an on-demand report. The UE capabilities include, but are not limited to, one or more of the following:

- Indication, whether the UE 100 is capable of reporting the association of one or more RS resources (for positioning, sensing, or ranging) with a UE TX AEGs or an AEG ID to the location/sensing server, RAN, or other UEs, as well as how many TX AEGs or RS resources associations may be supported.

- Indication, whether the UE 100 is capable to measure one or more RS resources with one or more UE RX AEGs and to report the associated measurements with one or more UE RX AEGs to the location/sensing server, RAN 204, or other UEs, as well as the number of RX AEGs or RS resources/measurements associations that may be supported.

- Indication, whether the UE 100 is capable to provide associated measurements with one or more UE RXTX AEGs, and/or one or more RS resources, and/or one or more UE RX AEGs/TX AEGs, to the location/sensing server, RAN 204, or other UEs.

The AEGs 103 in the above bullets may also include AEG classes.

FIG. 7 shows signaling for requesting and reporting AEG association information with RS resources and/or measurements. Generally speaking, in the first step 701, RAN/UE AEG association information (e.g., Indication of AEGs and AEG classes) may be requested by the location/sensing server. In the second step 702, BS/UE AEG association information is reported to the location server by the BS 204 or the UE 100.

Concerning the first signaling 701 “request AEG(s) association with RS resource(s)/measurement(s)”, it may be performed with different options depending on whether such the setting of AEG is determined by the RAN204 or the UE 100 or is configured by the Location/Sensing server. Specifically, it includes but is not limited to one or more of the following options denoted in the table below.

Concerning the second signaling 702 “report AEG(s) association with RS resource(s)/measurement(s)”, the report can be event-triggered, on-demand, semi-periodic, or periodic, depending on the configuration of the report request. When reporting the AEG(s) association with RS resource(s) or measurement(s), the time indication (e.g., timestamp, measurement instance indication) may also be reported along with the association. The report destination may be the Location/Sensing server, the RAN 204, or the UE 100. The BS AEG information may be forwarded by the Location/sensing server to the UE 100 or directly sent by RAN 204 to the UE 100.

The UE/BS TX/RX/RXTX AEG association with RS resources/measurements may be updated according to the signaling given in FIG. 8: The first signaling 801 indicates requesting to update or configuring how to update AEG(s) associations with RS resource(s)/measurement(s). Specifically, the UE 100 or BS 204 may be requested by the location/sensing server / RAN 204 I UE(s) 100 to report the update (e.g., on-demand), or UE 100 / BS 204 may be configured by the location/sensing server to report the update with certain update criteria (e.g., period, event- triggered). This signaling may be optional or may be combined with the first signaling 701 in FIG. 7. The update of AEG(s) association may also be unsolicited reported by UE/BS. The second signaling 802 indicates the update of AEG(s) associations with RS resource(s)/measurement(s) based on the request to update/configuration how to update in the first signaling 801 or unsolicited update. When updating the AEG(s) association with RS resource(s) or measurement(s), the time indication (e.g., timestamp, measurement instance indication) may also be updated along with the association.

In the following, several signaling embodiments are provided, an overview of which is given in the table below. The table shows an overview of relevant AEGs 103 for positioning, sensing, or ranging techniques, or modes:

The terms used in the table are explained in the following:

The term “Mode” (“UE-assisted“ and “UE-based”) indicates two positioning, sensing, or ranging modes that have different procedures on measurement and report. For the UE-assisted mode, measurements and/or measurement quality on positioning, ranging, or sensing reference signals are performed at the UE or network side, and/or reported to the location/sensing server in the network. The position or sensing results are calculated at the location/sensing server in the network. For the UE-assisted positioning, UE obtains measurement(s) and/or measurement quality on positioning/ranging/sensing reference signal(s) either by measurement performed at UE side or measurement results shared by network. Location/sensing results are calculated at UE side.

The terms of the techniques may have the following meaning: DL, UL, or SL denote downlink, uplink, and sidelink, respectively. AOD, or AOA denote angle-of-departure and angle-of- arrival techniques. The prefix (D)- before AOD and AOA indicates differential AOD and AOA, respectively. AOA/AOD may also be estimated based on antenna-switching, Doppler, or Velocity techniques. Bistatic sensing denotes a sensing scenario in which transmitting and receiving entities for sensing are separated by a distance comparable to the expected target distance. A DL bi-static sensing scenario is exemplarily illustrated in FIG. 9, in which DL- PRSs are sent via direct and reflected links. Alpha is the differential angle between PRS1 and PRS2 at the base station assuming that stable global or local coordinates are used. Phi AEG is the shift of local coordinates of cars at two instances (here assuming only orientation changes). Bi-static angle (Theta), the angle subtended between the transmitter, target and receiver in a bistatic sensing, may be calculated using A0A2, Phi AEG, and Alpha. FDOA denotes frequency different of arrival positioning techniques in which the UE/BS RX-TX frequency difference is exploited to enable Doppler based angle estimation (i.e., AOA/AOD). Uu link indicates the radio interface between the UE and Node B/BS. SL (sidelink) indicates the radio interface between UEs. Uu-bi-directional- indicates the positioning, sensing, or ranging technique in which reference signals are sent and measured via Uu link. SL-bi-directional- indicates the positioning, sensing, or ranging technique in which reference signals are sent and measured in both directions (backwards and forwards) of sidelink. Monostatic sensing denotes the sensing scenario that transmitting and receiving entities for sensing are co-located.

In the following, the embodiments from each row of the table are going to be described in detail. For each embodiment, the order of signaling may be exchanged. Same signaling may also occur several times according to the requirement of the positioning, or sensing service.

The Signaling procedure for UE-assisted DL-(D)AOD/(D)AOA/Bi-static sensing with AEG support is now described in view of FIG. 10:

- First step 1001 : The capabilities of the UE 100 for RX AEG may be requested by the location/sensing server or RAN 204. If the location server is a location management function (LMF) in a 5G core network (5GC), then this signaling may use the interface of LPP or RRC. If the location server is in the RAN network, the X2/Xn/Fl interface may also be considered.

- Second step 1002: The location/sensing server requests the association of BS TX AEGs with DL RS resources for a positioning, sensing, or ranging purpose, and/or for association of UE RX AEGs with measurements for a positioning, sensing, or ranging purpose. Such a request may also include the request to update of such association information. Details of this signaling are given above. This signaling may not be a dedicated signaling, instead it may be piggybacked with other positioning assistance data provision signaling. If the location server is an LMF in a 5GC, this signaling may use the interface of LPP/NRPPa/RRC.

- Third step 1003: Signaling for location/sensing server to provide assistance information for positioning, sensing, or ranging purpose is performed. This signaling may be a standard step in conventional positioning service procedures for LTE and 5G-NR.

- Fourth step 1004: The RAN 204 transmits DL RS for positioning, sensing, or ranging purpose.

- Fifth step 1005: Signaling for the location/sensing server to request and configure a measurement report to BS/UEs is performed. The message from the second step 1002 may be piggybacked in this step to request the association of BS TX AEGs and/or UE RX AEGs specifically for the current positioning or sensing instance (i.e., the configured report may only be valid for the current positioning or sensing RS measurement). If the location server is LMF in 5GC, this signaling may use the interface of LPP/NRPPa/RRC.

- Sixth step 1006: The RAN/ or E reports the associations of a BS TX AEG and/or a UE RX AEG to the location/sensing server. The details of this signaling are given above. If the location server is an LMF in a 5GC, this signaling may use the interface of LPP/NRPPa/RRC.

- Seventh step 1007: The RAN/UE updates the associations of BS TX AEG(s) and/or UE RX AEG(s) to the location/sensing server. The details of this signaling are give above. If the location server is an LMF in a 5GC, this signaling may use the interface of LPP/NRPPa/RRC.

As mentioned before, NRPPa may be replaced by the NG interface for sensing. LPP may be replaced by a general interface between UE/entity in core via NG/NAS/RRC.

The Signaling procedure for UE-assisted DL-(D)AOD/(D)AOA/Bi-static sensing with AEG support is now described in view of FIG. 11 :

- First step 1101 : The location/sensing server requests the association of BS TX AEG(s) with DL RS resource(s) for a positioning, sensing, or ranging purpose. Such a request may also include a request to update association information. Details of this signaling are given above. This signaling may not be a dedicated signaling, instead it may be piggybacked with other positioning assistance data provision signaling. If the location server is an LMF in 5GC, this signaling may use the interface of NRPPa.

- Second step 1102: The signaling for the location/sensing server provides assistance information for a positioning, sensing, or ranging purpose.

- Third step 1103: The RAN 204 transmits a DL RS for a positioning, sensing, ranging purpose.

- Fourth step 1104: The signaling for the location/sensing server to request and configure measurement report to a BS is performed, which is similar to Step 1005 in FIG. 10. If the location server is an LMF in 5GC, this signaling may use the interface of NRPPa. - Fifth step 1105: The associations ofBS TX AEG(s) are reported to the location/ sensing server. This association information between BS TX AEG(s) and DL RS resource(s) may be directly provided by the RAN 204 to the UE 100 via Uu link (i.e. an RRC interface) or may be forwarded from the location/sensing server to the UE 100. Therefore, if the location server is an LMF in 5GC, this signaling may use the interface of LPP/NRPPa/RRC.

- Sixth step 1106: The associations of BS TX AEG(s) are updated. As step 5, such information may be directly provided by RAN to the UE via Uu link (i.e. RRC interface) or be forwarded from Location/sensing server to the UE. Therefore, if the location server is LMF in 5GC, this signaling may use the interface of LPP/NRPPa/RRC.

The Signaling procedures for UE-assisted and UE-based UL-(D) A0D/(D) AO A/Bi- static Sensing with AEG(s) support are depicted in FIG. 12 (a) and FIG. 12 (b), respectively. The procedures are similar to those described in view of FIG. 10 and FIG. 11, apart from the differences described as follows.

The differences between FIG. 10 and FIG. 12 (a) are:

- First step 1201a: “UE’s capability of RX AEG” in FIG. 10 is replaced by “UE’s capability of TX AEG” in FIG. 12 (a), due to UL transmission of RSs that is assumed here.

- Steps 1202a, 1206a, and 1207a: “BS TX AEG”, “UE RX AEG”, “DL RS“ in FIG. 10 are replaced by “UE TX AEG”, “BS RX AEG”, “UL RS” in FIG. 12 (a), respectively.

- Step 1204a: “DL-PRS” in FIG. 10 is replaced by “UL-PRS/SRS” in FIG. 12 (a).

The differences between FIG. 11 and FIG. 12 (b) are:

- Steps 1201b, 1205b, 1206b: “BS TX AEG” in FIG. 11 is replaced by “BS RX AEG” in FIG. 12 (b).

- Step 1203b: “DL-PRS” in FIG. 10 is replaced by “UL-PRS/SRS” in FIG. 12 (b).

The detailed procedure in FIG. 12 (b) could be interpreted like the ones described in view of FIG. 10 and FIG. 11 by applying the above modifications.

The signaling procedure for UE-assisted SL-(D)AOD/(D)AOA/Bi-static sensing with AEG support is depicted in FIG. 13 (a) with following details: - First step 1301a: The TX-UE’s capabilities of TX AEG(s) or the RX-UE’s capabilities of RX AEG(s) may be requested by the location/sensing server or RAN. The procedure is detailed above. If the location server is a location management function (LMF) in a 5G core network (5GC), then this signaling may use the interface of LPP or RRC or PC5-RRC. If the location server is in the RAN network, X2/Xn/Fl interface may also be considered.

- Second step 1302a: The location/sensing server requests the association of TX-UE TX AEG(s) with SL RS resource(s) for a positioning, sensing, or ranging purpose, and/or the association of RX-UE RX AEG(s) with measurements for a positioning, sensing, or ranging purpose. Such a request may also include the request to update such association information. Detailed signaling contents are given above. This signaling may not be a dedicated signaling, instead it may be piggybacked with other positioning assistance data provision signaling. If the location server is an LMF in a 5GC, this signaling may use the interface of LPP/RRC/PC5-RRC.

- Third Step 1303a: The signaling for the location/sensing server provides assistance information.

- Fourth Step 1304a: The TX-UE transmits an SL RS for a positioning, sensing, or ranging purpose.

- Fifth Step 1305a: The signaling for the location/sensing server requests and configures a measurement report to the UEs. The message in step 1302a may be piggybacked in this step to request the association of TX-UE TX AEG(s) and/or RX-UE RX AEG(s) specifically for the current positioning/sensing instance (i.e., the configured report is only valid for the current positioning/ sensing RS measurement). If the location server is an LMF in a 5GC, this signaling may use the interface of LPP/RRC/PC5-RRC.

- Sixth step 1306a: The location/sensing server collects the reports regarding the associations of TX AEG(s) and/or RX AEG(s) from the TX-UE and the RX-UE, respectively. The details of this signaling are give above. If the location server is an LMF in a 5GC, this signaling may use the interface of LPP/RRC/PC5-RRC. - Seventh step 1307a: The TX-UE and/or the RX-UE may update the associations of TX AEG(s) and/or RX AEG(s) and provide this update to the location/sensing server. The details of this signaling are given above. If the location server is an LMF in a 5GC, this signaling may use the interface of LPP/RRC/PC5-RRC.

The Signaling procedure for UE-based SL-(D)AOD/(D)AOA/Bi-static sensing with AEG(s) support is illustrated in FIG. 13 (b) with following details:

- First Step 1301b: The association of TX-UE TX AEG(s) with SL RS resource(s) for a positioning, sensing, or ranging purpose, and/or association of RX-UE RX AEG(s) with measurements, are provided to the location/sensing server and/or the UE entity that is responsible for the position or sensing estimation. If the location server is an LMF in a 5GC, this signaling may use the interface of LPP/RRC/PC5-RRC.

- Second Step 1302b: The signaling for the location/sensing server to provide assistance information to the UEs for performing SL positioning, sensing, or ranging.

- Third step 1303b: The TX-UE transmits SL RS for a positioning, sensing, or ranging purpose.

- Fourth step 1304b: The signaling for the location/sensing server is performed to request and configure a measurement report to UEs. The message in step 1302b may be piggybacked in this step to request the association of TX-UE TX AEG(s) and/or RX-UE RX AEG(s) specifically for the current positioning/sensing instance (i.e., a configured report is only valid for a current positioning/ sensing RS measurement). If the location server is an LMF in a 5GC, this signaling may use the interface of LPP/RRC/PC5-RRC.

- Fifth step 1305b: The associations of TX AEG(s) and/or RX AEG(s) from the TX-UE and the RX-UE are provided to the UE entity that is responsible for position/sensing estimation. The details of this signaling are given above. If the location server is an LMF in a 5GC, this signaling may use the interface of LPP/RRC/PC5-RRC.

- Sixth Step 1306b: The TX-UE and/or the RX-UE may update the associations of TX AEG(s) and/or RX AEG(s) and provide this update to the location/sensing server. The details of this signaling are given above. If the location server is an LMF in a 5GC, this signaling may use the interface of LPP/RRC/PC5-RRC.

The Signaling procedures for UE-assisted and UE-based Uu-bi-directional- (D)AOA/(D)AOD/FDOA with AEG support are depicted in FIG. 14 (a) and FIG. 14 (b). The procedures are similar to those described in view of FIG. 10 and FIG. 11 above, apart from the differences described as follows:

The differences between FIG. 10 and FIG. 14 (a) are

- First step 1401a: “UE’s capability of RX AEG” in FIG. 10 is replaced by “UE’s capability of RXTX AEG” in FIG. 14 (a), due to bi-directional (DL/UL) transmission of RSs that is assumed here.

- Steps 1402a, 1406a, 1407a: “BS TX AEG”, “UE RX AEG”, “DL RS“ in FIG. 10 are replaced by “BS RXTX AEG”, “UE RXTX AEG”, “DL/UL RS” in FIG. 14 (a), respectively.

- Step 1404a: “DL-PRS” in FIG. 10 is replaced by “DL/UL-RS” in FIG. 14 (a).

The differences between FIG. 11 and FIG. 14 (b), are:

- Steps 1401b, 1405b, 1406b: “BS TX AEG”, “UE RX AEG” in FIG. 11 are replaced by “BS RXTX AEG”, “UE RXTX AEG” in FIG. 14 (a), respectively.

- Step 1403b: “DL-PRS” in FIG. 11 is replaced by “DL/UL-RS” in FIG. 14 (b).

The detailed procedure in FIG. 14 could be interpreted like the ones described in view of FIG. 10 and FIG. 11 by applying the above modifications.

The Signaling procedures for UE-assisted and UE-based SL-bi-directional- (D)AOA/(D)AOD/FDO A with AEG(s) support are depicted in FIG. 15 (a) and FIG. 15 (b), respectively. The procedures are similar to those described in view of FIG. 13, apart from the differences described as follows. The differences between FIG. 13 (a) and FIG. 15 (a) are: - Step 1501a: “UE’s capability of TX and/or RX AEG” in FIG. 13 (a) is replaced by “UE’s capability of RXTX AEG” in FIG. 15 (a), due to bi-directional (SL forward and feedback) transmission of RSs that is assumed here.

- Step 1502a, 1506a, 1507a: “UE TX AEG”, “UE RX AEG” in FIG. 13 (a) are replaced by “UE RXTX AEG” in FIG. 15 (a), respectively.

The differences between FIG. 13 (b) and FIG. 15 (b) are:

- Step 1501b, 1505b, and 1506b: “UE TX AEG”, “UE RX AEG” in FIG. 13 (b) are replaced by “UE RXTX AEG”, FIG. 15 (b), respectively.

The detailed procedure in FIG. 15 could be interpreted like the ones described in view of FIG. 13 by applying the above modifications.

For mono-static Sensing performed either by the RAN 204 or the UE 100, UE RXTX AEG(s) may be associated with RS (for positioning, sensing, or ranging purpose) and/or angle-based measurements of TX and RX. A range can be estimated based on angle-based measurements using transmitter and receiver antennas, as well as optionally with time-based measurement (e.g., round-trip-time). Signaling procedures can be referred to the ones in FIG. 15.

FIG. 16 shows a schematic view of a method 1600 according to an embodiment of the present disclosure. The method 1600 is for localization and comprises the steps of obtaining 1601, by a wireless device 100, a first reference signal 101; obtaining 1602, by the wireless device 100, a second reference signal 102; and determining, by the wireless device 100, an angle-based error group, AEG, 103 based on the first reference signal 101 and the second reference signal 102; wherein the AEG 103 indicates that an angle-based error between the first reference signal 101 and the second reference signal 102 is below a predefined threshold.

The present disclosure has been described in conjunction with various embodiments as examples as well as implementations. However, other variations can be understood and effected by those persons skilled in the art and practicing the claimed disclosure, from the studies of the drawings, this disclosure, and the independent claims. In the claims as well as in the description, the word “comprising” does not exclude other elements or steps and the indefinite article “a” or “an” does not exclude a plurality. A single element or other unit may fulfill the functions of several entities or items recited in the claims. The mere fact that certain measures are recited in the mutual different dependent claims does not indicate that a combination of these measures cannot be used in an advantageous implementation.