WO2024082214A1

WO2024082214A1 - Improved target positioning by using multiple terminal devices

Info

Publication number: WO2024082214A1
Application number: PCT/CN2022/126431
Authority: WO
Inventors: Lu Zhang
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2022-10-20
Filing date: 2022-10-20
Publication date: 2024-04-25

Abstract

A method at a network node for positioning a target that carries a first number of terminal devices is provided. The first number is greater than 1. The method comprises: determining a set of filtered measurements based on at least a first number of sets of original measurements that are measured by a same RAT, each of the first number of sets being associated with a corresponding one of the first number of terminal devices; and determining a position of the target based on at least the set of filtered measurements.

Description

IMPROVED TARGET POSITIONING BY USING MULTIPLE TERMINAL DEVICES

Technical Field

The present disclosure is related to the field of telecommunication, and in particular, to a network node, a terminal device, and methods for improved target positioning by using multiple terminal devices.

Background

With the development of the electronic and telecommunication technologies, mobile devices, such as a mobile phone, a smart phone, a laptop, a tablet, a vehicle mounted device, becomes an important part of our daily lives. One of the key features provided by a mobile device is location-based service (LBS) . Because of the popularities of social networks and the widespread usage of mobile devices, demands for LBS are increased in both indoor and outdoor environments.

Indoor positioning could be done with or without utilizing cellular mobile networks (e.g., 4G Long Term Evolution (LTE) or 5G New Radio (NR) networks) . There are so many indoor positioning schemes without utilizing cellular mobile networks (i.e., the third-party schemes) . For example, the schemes which exploit some certain combination of the following technologies: Wi-Fi fingerprinting, ZigBee/Bluetooth fingerprinting, Geomagnetic fingerprinting, inertial navigation, Radio Frequency Identification (RFID) , Ultra-Wideband (UWB) communications, visible light communications, ultrasonic wave, infrared ray, map matching, etc.

Further, there are also many other cellular-based indoor positioning schemes. For indoor positioning schemes with utilizing cellular mobile networks (i.e., cellular-based indoor positioning) , several traditional positioning methods exist in the latest 4G standards and can be naturally applied to 5G networks. A non-exhaustive list of such positioning techniques is provided below, and it is merely a selection of technologies that vendors and operators have at the moment and are likely to investigate first for the positioning service:

- Enhanced cell identification (E-CID) : E-CID offers a range of measurements for positioning purposes: Angle-of-arrival/departure (AoA/AoD) , Received signal strength with path-loss model (RSSPLM) , Timing advance type 1 (TADV1, essentially a round trip time) or type 2 (TADV2) .

- RF pattern matching (or called fingerprinting) : This method needs a database of signal fingerprints associated to a geographic position. Typically, a fingerprint of a certain geo-location is associated with a signal measurement, such as the received signal strength (RSS) , to find the mobile device. The position accuracy of this method depends on the calibration of the database and the quality of the location-dependent measurements.

- Methods that are based on ranging measurements: Typically, they are observed or uplink time difference of arrival (OTDoA or UTDoA) , also known as downlink or uplink time difference of arrival (DL-TDoA or UL-TDoA) in 5G. These two methods use the same principle of measuring reference signal time difference (RSTD) , where positioning reference signal (PRS) for OTDoA and sounding reference signal (SRS) for UTDoA. The RSTD is the RS time of arrivals (ToA) difference between each base station and a reference base station. A conventional method to estimate the ToA is to find the time delay at which the correlation between the RS and the received signal has its maximum. When compared to the OTDoA, the biggest disadvantage of the UTDoA is that it may be difficult for different base stations (BSs) to hear user equipments (UEs) simply due to transmit power limitations at the side of UE.

Further, because satellite signals would be lost in indoor scenarios, indoor positioning schemes do not include assisted GNSS (A-GNSS) , which is a service that helps GNSS receivers achieve a faster time to the first fix (in less than 30 seconds) by supplying essential information (e.g., almanac, ephemeris) through cellular network data service.

Based on the existing extensive analyses and comparisons e.g., in the references [1] and [2] , the most preferred cellular-based indoor positioning technology is OTDoA. Fig. 1 is a diagram illustrating an exemplary telecommunication network 10 in which the position of a UE 100 may be determined by using OTDoA. As shown in Fig. 1, the network 10 may comprise multiple BSs 105-1 through 105-3 (collectively, the BS 105) , and a UE 100 may want to determine its own position by using OTDoA.

Most OTDoA positioning schemes only consider 2-D positioning. For 2-D positioning, at least three base stations (e.g., the BS #1 105-1 through the BS #3 105-3) are required such that at least two RSTD measurements can be derived with three ToAs. Two RSTDs give two distance differences representing two hyperbolas, and the intersection of the hyperbolas corresponds to the UE position, referred to as the trilateration positioning.

Referring back to Fig. 1, a difference between any two measured ToAs (e.g., any two of τ ₁, τ ₂, τ ₃) may be calculated, and it may eliminate the UE signal arrival timing offset. The resulting hyperbolas (e.g., those indicated by "τ ₁ -τ ₃" and "τ ₁ -τ ₂" ) may define possible locations of the UE 100 (e.g., the solid curves shown in Fig. 1) and the intersection between all calculated hyperbolas may be determined as the actual location of the UE 100 (in absence of error sources) . Further, due to measurement errors of the ToAs, some uncertainty may be introduced as shown by the dotted curves on both sides of the solid curves, and therefore a region (e.g., the shadow region in Fig. 1) , instead of a single intersection point of two hyperbolas, is determined as a region in which the UE 100 is located.

Since the hyperbolic equations are nonlinear, several iterative and non-iterative methods (e.g., the references [3] - [5] ) have been developed to solve the problem with achieving the maximum-likelihood (ML) or the near ML solution.

For some applications, 2-D location information will not be sufficient. For OTDoA 3-D positioning, it is simple to see that at least four base stations are required to provide three RSTD measurements (e.g., the references [6] - [8] ) . Also, several methods have been proposed to utilize only three base stations to do OTDoA 3-D positioning (e.g., the references [9] - [10] ) .

Summary

Based on the extensive results under the context of 4G LTE networks, the positioning accuracy of OTDoA can only be typically "＜50m" in horizontal plane and be "＜10m ～ 50m (depending on used methods) " in vertical plane.

However, based on 3GPP TR 22.862 v14.1.0 (which is incorporated herein by reference in its entirety) , for 5G NR systems, cellular network based positioning should be supported with accuracy from 10m to ＜1m in 80%of situations, including indoor, outdoor, and urban environments.

Given the new technical features within 5G, the main research trends "cellular-based indoor positioning" are classified as:

1) Massive MIMO (mMIMO) channel fingerprint: It makes sense to use large antenna arrays that oversample the spatial dimension of a wireless channel (thus benefiting from, e.g., increased angular resolution, resilience to small-scale fading, and array gain effects) to aid the positioning task. For fingerprinting-based methods, the location is estimated by comparing online measurements with a set of training samples at known positions.

The obvious drawback is that the pattern features of each location have to be measured prior to position estimation, and those locations with similar pattern features might be hard to distinguish. Also, in dynamic environments, a previously collected pattern might not remain accurate. For emergency positioning, the assumption that most locations already have stored measurements might not be viable.

2) More resolvable angle estimation with mMIMO antenna array: the large number of antennas would result in high degree of resolvability of angles (e.g., AoA/AoD) , because of narrower beams. The most popular methodology in this research direction is to do angle estimation by utilizing beam-RSRP (BRSRP) measurements and enhanced Kalman filtering.

However, to ensure the good performance of angle estimation, all of the existing works assume the existence of LOS (line of sight) path (s) between BS (s) and the target UE.

3) Network densification: In ultra-dense 5G networks, a significant increase in the deployment of the so-called small cells (pico-and femtocells) should be expected. This will have a significant role to play in the positioning services, because adding more transmitters would increase localization accuracy quite considerably and reduce the effect of synchronization error. Furthermore, cooperative positioning with device-to-device communications in ultra-dense 5G networks is expected to achieve seamless or ubiquitous positioning with accuracies below one meter.

However, the cost involved in maintaining a dense infrastructure by each mobile network operator (MNO) in the same area may not be viable, due to significantly increased capital expenditure (CAPEX) and operating expense (OPEX) . One possible solution is to let different MNOs cooperate in the process of deploying and maintaining such ultra-dense infrastructure together; but obviously the infrastructure sharing would raise questions on the customer′s billing and maintenance cost sharing per individual MNO.

4) Utilization of Digital Indoor System (DIS) : In 5G era, for cellular-based indoor deployment, besides also keeping the existence of "the traditional passive Distributed Antenna System (DAS) already deployed in 4G networks" and "the so-called active DAS (also called multi-channel joint DAS) newly proposed for 5G" , the focused new deployment way is "DIS" .

DIS consists of digital headend, convergence unit and base-band unit (BBU) , as a three-layer architecture. BBU and digital headend implement the baseband and radio function respectively. Convergence unit is introduced to the system for easy extension and deployment, that provides not only power supply to digital headend, but also converges data from/to multiple digital headends so as to reduce the number of required interfaces of BBU. All components are connected to carrier digital signals using Ethernet cable or optical fiber cable.

For the product of digital headend, some vendors call it "pico-style radio remote unit (pRRU) " and some other vendors call it "DoT" (Note: DoT is not an abbreviation but an English word) ; for the product of convergence unit, some vendors call it "radio-hub (R-Hub) " while some other vendors call it "indoor radio unit (IRU) " . In some embodiments of the present disclosure, the term "DoT" is used to represent digital headend and the term "IRU" is used to represent convergence unit.

DIS usually combines multiple DoTs into one cell, which reduces the number of cells so that severe inter-cell interference and frequent handover could be avoided. In general, one IRU is connected at least L (L＞1) DoTs while one IRU corresponds to at least M (M≥1) cells. Based on the typical requirement from MNOs in China, using DoT with 2T2R and 100 MHz cell bandwidth as the example, L = 8 and M = 1 (i.e., each group of L ÷ M = 8 ÷ 1 = 8 DoTs acts as a cell) is mandatory and L = 8 and M = 2 (i.e., each group of L ÷ M = 8 ÷ 2 = 4 DoTs acts as a cell) is optional. In some embodiments, a DoT can only support L = 8 and M = 1.

One BBU is connected at most K=N÷ M (K≥ 3) IRUs, if the supported maximum number of cells per BBU is N. In some embodiments, at most N = 6 and at most M = 1 can be supported, so that at most K= 6 ÷ 1 = 6 IRUs can be connected to one BBU.

Fig. 2 is a diagram illustrating an exemplary DIS 20 for which improved target positioning by using multiple terminal devices may be applicable according to an embodiment of the present disclosure. As shown in Fig. 2, the DIS 20 may comprise a BBU 210, which can be connected to one or more IRUs 220-1 through 220-2 (collectively, the IRUs 220) . Each of the IRUs 220 can be connected to one or more DoTs 230-1 through 230-8 (collectively, the DoT 230) . However, the present disclosure is not limited thereto. In some other embodiments, different numbers of BBUs, IRUs, and/or DoTs may be deployed in the DIS 20.

In fact, being limited by the capacity of each BBU and the capacity of transportation (including fronthaul and backhaul) , at least for now and recent future, it is impossible to let each DoT act as a cell. For example, when 6 IRUs are connected to one BBU (where each IRU is connected with 8 DoTs) , it is required that one BBU can support 6×8 = 48 cells. For China Telecom, using 3.5 GHz frequency band as the example, the bandwidth of one cell is 100 MHz, when one BBU needs to support 48 cells, the corresponding capacity requirements on transportation (including fronthaul and backhaul) will be unaffordable.

Clearly, when each group of L DoTs acts as a cell (L = 8 for now and possibly L = 4 in recent future) , although one UE can receive PRS signals sent from three or more DoTs, in most cases, those DoTs correspond to only one cell, so that the PRS signals of those DoTs cannot be distinguished and the number of positioning-related measurements (e.g., ToA measurements when using OTDoA) can only be one but not three or more. That is to say, the densification of digital headends in a DIS cannot be exploited for OTDoA-based indoor positioning at all, unless i) each DoT can act as a cell (which is infeasible) or ii) a smart mechanism of PRS allocation and transmission can be designed for L DoTs that belong to one cell (which is challenging) .

Of course, people may consider using UTDoA-based indoor positioning where an SRS signal sent from UE is measured at each DoT, the above problem encountered in OTDoA-based indoor positioning will not occur. However, due to the following reasons, UTDoA is generally worse than OTDoA in terms of positioning performance and wireless resource utilization-efficiency:

- When the number of UEs that need to use positioning is not so small, because the SRS resources for different UEs need to be orthogonal, either the UEs need to be put in a waiting list so that the response time of positioning request is long (which means bad performance and user experience) or so many wireless resources in time-frequency domains are occupied by SRS for positioning (which means low utilization-efficiency of wireless resource) .

- As concluded in the reference [11] , the most accurate terrestrial positioning method is OTDoA, which can provide highly accurate positioning in most parts of a cellular network and for most typical environments. UTDoA performance may approach that of OTDoA in some deployment scenarios, assuming the use of enhanced UL receiver, because it may be difficult for enough BSs to receive SRS from a UE considering the transmit power limitation at the side of UE.

√ Here, for indoor environment, UL coverage will not be so limited by UE′s transmit power; but, due to the obvious difference between transmit power level of indoor gNB and that of UE, on average, under the same DIS deployment, the number of DoT-resulted ToA measurements obtained via UTDoA will be smaller than that obtained via OTDoA.

√ When the distance between any two neighboring digital headends is around 20 ～ 30 meters (which is the requirement on deployment density of digital headends for 5G DIS bidding in China in 2021) , according to the performance results of some prior art solutions.

√ , the indoor positioning accuracy resulted by applying UTDoA to a DIS can only be 3 ～ 10 meters. In particular, to achieve the best positioning accuracy (i.e., 3 ～ 5 meters) , UTDoA needs to utilize "SRS optimized for positioning" prescribed in 3GPP Rel-16.

- Generally, in most cases, the response time of positioning request for UTDoA is longer than (i.e., worse than) that for OTDoA [11] .

In a word, it will be quite meaningful and valuable for making "the densification of digital headends in a DIS" utilizable in OTDoA-based indoor positioning to improve positioning accuracy to be smaller than 3 meters. Fortunately, this problem has been solved in the international Patent Cooperation Treaty (PCT) application (PCT/CN2022/093880) (which is incorporated herein by reference in its entirety) , in which a smart and feasible mechanism of PRS allocation and transmission is designed for multiple DoTs that belong to one cell.

However, to make the positioning accuracy be further improved (e.g., the accuracy can be smaller than 1 meter with a high probability) , further enhancement is still needed.

Therefore, to address or at least alleviate the above problems, some embodiments of the present disclosure are provided.

According to a first aspect of the present disclosure, a method at a network node for positioning a target that carries a first number of terminal devices is provided. In some embodiments, the first number is greater than 1. The method comprises: determining a set of filtered measurements based on at least a first number of sets of original measurements that are measured by a same Radio Access Technology (RAT) , each of the first number of sets being associated with a corresponding one of the first number of terminal devices; and determining a position of the target based on at least the set of filtered measurements.

In some embodiments, the step of determining the position of the target comprises: determining the position of the target by using a positioning scheme applicable to a single one of the first number of terminal devices while the set of original measurements, which is associated with the single terminal device and is input to the positioning scheme, is replaced with the set of filtered measurements. In some embodiments, the step of determining the set of filtered measurements comprises: determining each member of the set of filtered measurements as a weighted average of a first number of original measurements, each of the first number of original measurements belonging to a set of original measurements associated with a corresponding one of the first number of terminal devices.

In some embodiments, when all of original measurements associated with a second number of terminal devices from the first number of terminal devices are Line Of Sight (LOS) measurements, the original measurements associated with only one of the second number of all-LOS-path terminal device are selected to determine the set of filtered measurements, and a weight associated with an original measurement is determined as follows: 1, when the original measurement is selected; and/or 0, when the original measurement is not selected. In some embodiments, when all of original measurements associated with a second number of terminal devices from the first number of terminal devices are LOS measurements, the original measurements associated with all of the second number of all-LOS-path terminal devices are selected to determine the set of filtered measurements, and a weight associated with an original measurement is determined as follows: a ratio of 1 to the second number, when the original measurement is selected; and/or 0, when the original measurement is not selected.

In some embodiments, when all of original measurements associated with a second number of terminal devices from the first number of terminal devices are LOS measurements, the original measurements associated with all of the second number of all-LOS-path terminal devices are selected to determine the set of filtered measurements, and a weight associated with an original measurement is determined as follows: a ratio of a Reference Signal Received Power (RSRP) corresponding to the original measurement to a sum of all RSRPs corresponding to the selected original measurements used for determining a corresponding filtered measurement, when the original measurement is selected; and/or 0, when the original measurement is not selected. In some embodiments, when at least one original measurement for each of the first number of terminal devices is a Non-LOS (NLOS) measurement, a weight associated with an original measurement is determined as a ratio of 1 to the first number. In some embodiments, when at least one original measurement for each of the first number of terminal devices is an NLOS measurement, a weight associated with an original measurement is determined as a ratio of an RSRP corresponding to the original measurement to a sum of all RSRPs corresponding to the first number of original measurements used for determining a corresponding filtered measurement.

In some embodiments, when at least one original measurement for each of the first number of terminal devices is an NLOS measurement, and when there are one or more LOS measurements among the original measurements used for determining a corresponding filtered measurement, a weight associated with an original measurement used for determining the corresponding filtered measurement is determined as follows: 1, when the original measurement is the only one LOS measurement among the original measurements used for determining the corresponding filtered measurement, or when the original measurement is one of multiple LOS measurements among the original measurements used for determining the corresponding filtered measurement and has an RSRP greater than RSRPs corresponding to other original measurements that are LOS measurements and used for determining the corresponding filtered measurement; and/or 0, otherwise.

In some embodiments, when at least one original measurement for each of the first number of terminal devices is an NLOS measurement, and when there is no LOS measurement among the original measurements used for determining a corresponding filtered measurement, a weight associated with an original measurement used for determining the corresponding filtered measurement is determined as a ratio of 1 to the first number. In some embodiments, when at least one original measurement for each of the first number of terminal devices is an NLOS measurement, and when there is no LOS measurement among the original measurements used for determining a corresponding filtered measurement, a weight associated with an original measurement used for determining the corresponding filtered measurement is determined as a ratio of an RSRP corresponding to the original measurement to a sum of all RSRPs corresponding to the first number of original measurements used for determining the corresponding filtered measurement. In some embodiments, the first number of terminal devices are separated from each other by a distance less than a first threshold.

In some embodiments, at least three members in each set from the first number of sets of original measurements are Time of Arrival (ToA) measurements, from which at least three members in the set of filtered measurements, which are filtered ToA measurements, are determined. In some embodiments, each of at least three ToAs associated with a terminal device is measured on a reference signal transmitted between the terminal device and a corresponding one of at least three access points, wherein the at least three access points comprise at least a reference access point, a first access point, and a second access point.

In some embodiments, a first filtered Reference Signal Time Difference (RSTD) for the reference access point and the first access point and a second filtered RSTD for the reference access point and the second access point are calculated as follows: the first filtered RSTD is calculated as a difference between a filtered ToA associated with the first access point and a filtered ToA associated with the reference access point; and/or the second filtered RSTD is calculated as a difference between a filtered ToA associated with the second access point and a filtered ToA associated with the reference access point.

In some embodiments, the positioning scheme comprises at least a ranging measurement based positioning scheme. In some embodiments, the positioning scheme comprises at least one of: Downlink Time Difference of Arrival (DL-TDoA) ; Uplink Time Difference of Arrival (UL-TDoA) ; and Multi-cell Round Trip Time (Multi-RTT) . In some embodiments, an access point is a digital headend when a digital indoor system is used to do indoor positioning. In some embodiments, the network node is at least one of: a Location Management function (LMF) ; and an access point.

In some embodiments, before the step of determining the set of filtered measurements, the method further comprises: receiving, from another network node, association information that indicates at least one of: that the target is associated with the first number of terminal devices; and that the set of filtered measurements is to be determined based on the first number of sets of original measurements associated with the first number of terminal devices. In some embodiments, when the network node is an LMF, the association information is received from a Location Service (LCS) server via a Gateway Mobile Location Center (GMLC) and an Access and Mobility Management Function (AMF) . In some embodiments, when the network node is an access point, the association information is received from an LCS server via a GMLC and an AMF. In some embodiments, the associated information is transmitted by the LCS server to the LMF.

In some embodiments, before the step of determining the set of filtered measurements, the method further comprises: determining whether all of the first number of terminal devices are co-located with the target or not. In some embodiments, the step of determining whether all of the first number of terminal devices are co-located with the target or not comprises: determining whether the first number of terminal devices are associated with a same serving cell ID; and determining whether RSRPs measured by the first number of terminal devices over one or more same reference signal (RS) resources have relative differences from each other less than a threshold.

In some embodiments, when compared with using one terminal device for positioning a target, the utilization of the first number of terminal devices and the corresponding filtered measurements improves the positioning scheme in terms of at least one of positioning accuracy and positioning integrity.

In some embodiments, reference signals that are measured comprise at least one of: a Positioning Reference Signal (PRS) ; and a Sounding Reference Signal (SRS) . In some embodiments, the RAT comprises one of: New Radio (NR) ; Long Term Evolution (LTE) ; Wi-Fi; and Bluetooth.

According to a second aspect of the present disclosure, a network node is provided. The network node comprises: a processor; a memory storing instructions which, when executed by the processor, cause the processor to carry out any of the methods of the first aspect.

According to a third aspect of the present disclosure, a network node for positioning a target that carries a first number of terminal devices is provided. In some embodiments, the first number is greater than 1. The network node comprises: a first determining module configured to determine a set of filtered measurements based on at least a first number of sets of original measurements that are measured by a same RAT, each of the first number of sets being associated with a corresponding one of the first number of terminal devices; and a second determining module configured to determine a position of the target based on at least the set of filtered measurements. In some embodiments, the network node may comprise one or more further modules, each of which may perform any of the steps of the method of the first aspect.

According to a fourth aspect of the present disclosure, a method at a terminal device for positioning a target that carries a first number of terminal devices comprising the terminal device is provided. In some embodiments, the first number is greater than 1. The method comprises: determining a set of filtered measurements based on at least a first number of sets of original measurements that are measured by a same RAT, each of the first number of sets being associated with a corresponding one of the first number of terminal devices; and determining a position of the target based on at least the set of filtered measurements.

In some embodiments, the step of determining the position of the target comprises: determining the position of the target by using a positioning scheme applicable to a single one of the first number of terminal devices while the set of original measurement, which is associated with the single terminal device and is input to the positioning scheme, is replaced with the set of filtered measurements. In some embodiments, the step of determining the set of filtered measurements comprises: determining each member of the set of filtered measurements as a weighted average of a first number of original measurements, each of the first number of original measurements belonging to a set of original measurements associated with a corresponding one of the first number of terminal devices.

In some embodiments, when all of original measurements associated with a second number of terminal devices from the first number of terminal devices are LOS measurements, the original measurements associated with all of the second number of all-LOS-path terminal devices are selected to determine the set of filtered measurements, and a weight associated with an original measurement is determined as follows: a ratio of an RSRP corresponding to the original measurement to a sum of all RSRPs corresponding to the selected original measurements used for determining a corresponding filtered measurement, when the original measurement is selected; and/or 0, when the original measurement is not selected.

In some embodiments, when at least one original measurement for each of the first number of terminal devices is an NLOS measurement, a weight associated with an original measurement is determined as a ratio of 1 to the first number. In some embodiments, when at least one original measurement for each of the first number of terminal devices is an NLOS measurement, a weight associated with an original measurement is determined as a ratio of an RSRP corresponding to the original measurement to a sum of all RSRPs corresponding to the first number of original measurements used for determining a corresponding filtered measurement.

In some embodiments, at least three members in each set from the first number of sets of original measurements are ToA measurements, from which at least three members in the set of filtered measurements, which are filtered ToA measurements, are determined. In some embodiments, each of at least three ToAs associated with a terminal device is measured on a reference signal transmitted between the terminal device and a corresponding one of at least three access points, wherein the at least three access points comprise at least a reference access point, a first access point, and a second access point.

In some embodiments, a first filtered RSTD for the reference access point and the first access point and a second filtered RSTD for the reference access point and the second access point are calculated as follows: the first filtered RSTD is calculated as a difference between a filtered ToA associated with the first access point and a filtered ToA associated with the reference access point; and/or the second filtered RSTD is calculated as a difference between a filtered ToA associated with the second access point and a filtered ToA associated with the reference access point. In some embodiments, the positioning scheme comprises at least a ranging measurement based positioning scheme.

In some embodiments, the positioning scheme comprises at least one of: DL-TDoA; UL-TDoA; and Multi-RTT. In some embodiments, an access point is a digital headend when a digital indoor system is used to do indoor positioning. In some embodiments, the terminal device is a UE. In some embodiments, each of the first number of terminal devices is a UE. In some embodiments, before the step of determining the set of filtered measurement, the method further comprises: receiving, from a network node, association information that indicates at least one of: that the target is associated with the first number of terminal devices; and that the filtered measurement is to be determined based on the first number of sets of measurements associated with the first number of terminal devices. In some embodiments, the association information is received from an LCS server via a GMLC, an AMF, and an access point. In some embodiments, the associated information is transmitted by the LCS server to the LMF.

In some embodiments, before the step of determining the set of filtered measurements, the method further comprises: determining whether all of the first number of terminal devices are co-located with the target or not. In some embodiments, the step of determining whether all of the first number of terminal devices are co-located with the target or not comprises: determining whether the first number of terminal devices are associated with a same serving cell ID; and determining whether RSRPs measured by the first number of terminal devices over one or more same RS resources have relative differences from each other less than a threshold.

In some embodiments, reference signals that are measured comprise at least one of: a PRS; and an SRS. In some embodiments, the RAT comprises one of: NR; LTE; Wi-Fi; and Bluetooth. In some embodiments, the set of original measurements associated with each of the rest of the first number of terminal devices other than the terminal device is sent to the terminal device via an inter-terminal device wireless connection. In some embodiments, the inter-terminal device wireless connection comprises at least one of: NR sidelink; LTE sidelink; Wi-Fi; and Bluetooth.

According to a fifth aspect of the present disclosure, a terminal device is provided. The terminal device comprises: a processor; a memory storing instructions which, when executed by the processor, cause the processor to carry out any of the methods of the fourth aspect.

According to a sixth aspect of the present disclosure, a terminal device for positioning a target that carries a first number of terminal devices comprising the terminal device is provided. In some embodiments, the first number is greater than 1. The terminal device comprises: a first determining module configured to determine a set of filtered measurements based on at least a first number of sets of original measurements that are measured by a same RAT, each of the first number of sets being associated with a corresponding one of the first number of terminal devices; and a second determining module configured to determine a position of the target based on at least the set of filtered measurements. In some embodiments, the terminal device may comprise one or more further modules, each of which may perform any of the steps of the method of the fourth aspect.

According to a seventh aspect of the present disclosure, a computer program comprising instructions is provided. The instructions, when executed by at least one processor, cause the at least one processor to carry out any of the methods of the first aspect and/or the fourth aspect.

According to an eighth aspect of the present disclosure, a carrier containing the computer program of the seventh aspect is provided. In some embodiments, the carrier is one of an electronic signal, optical signal, radio signal, or computer readable storage medium.

According to a ninth aspect of the present disclosure, a method at a telecommunication system for positioning a target that carries a first number of terminal devices is provided. In some embodiments, the first number is greater than 1. The method comprises: determining, at a network node and/or a terminal device, a set of filtered measurements based on at least a first number of sets of original measurements that are measured by a same RAT, each of the first number of sets being associated with a corresponding one of the first number of terminal devices; and determining, at the network node and/or the terminal device, a position of the target based on at least the set of filtered measurements.

In some embodiments, the terminal device is one of the first number of terminal devices. In some embodiments, when the set of filtered measurements is determined at the terminal device, the set of original measurements associated with each of the rest of the first number of terminal devices is sent to the terminal device via an inter-terminal device wireless connection. In some embodiments, the inter-terminal device wireless connection comprises at least one of: NR sidelink; LTE sidelink; Wi-Fi; and Bluetooth. In some embodiments, the network node is a network node of the second or third aspect. In some embodiments, the terminal device is a terminal device of the fifth or sixth aspect.

According to a tenth aspect of the present disclosure, a telecommunication system for positioning a target that carries a first number of terminal devices is provided. In some embodiments, the first number is greater than 1. The telecommunication system comprises a network node and/or one of the first number of the terminal devices, for determining a set of filtered measurements based on at least a first number of sets of original measurements that are measured by a same Radio Access Technology (RAT) , each of the first number of sets being associated with a corresponding one of the first number of terminal devices; and determining a position of the target based on at least the set of filtered measurements.

With some embodiments of the present disclosure, by utilizing at least two terminal devices using a same RAT (e.g. multiple 5G UEs) in one positioned target, the positioning accuracy can be improved. Further, with some embodiments of the present disclosure, by utilizing at least two terminal devices using a same RAT (e.g., multiple 5G UEs) in one positioned target, the positioning integrity can be improved. For example, upon exploiting a DIS and applying one "relative time difference" based positioning scheme, which is also called ranging measurement based positioning scheme, (e.g., OTDoA/UTDoA) to the DIS, for every available measurement of time difference (which will be further utilized to calculate the position of the target) , it is obtained by appropriately doing filtering (or called syncretic processing) on the corresponding multiple groups of ToA measurements generated by the multiple UEs, thus enhancing the positioning accuracy and integrity. Further, although the focused scenario is indoor positioning using DIS, the proposal can also be used for indoor positioning without DIS and for outdoor positioning. Furthermore, the methods proposed in the international PCT application (PCT/CN2022/093880) can be used in the solution according to some embodiments of the present disclosure to enable the usage of OTDoA in a DIS, so that a more accurate and trustworthy 5G indoor positioning may be achieved.

Brief Description of the Drawings

The foregoing and other features of the present disclosure will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. Understanding that these drawings depict only several embodiments in accordance with the disclosure and therefore are not to be considered limiting of its scope, the disclosure will be described with additional specificity and detail through use of the accompanying drawings.

Fig. 1 is a diagram illustrating an exemplary telecommunication network in which the position of a UE may be determined by using OTDoA.

Fig. 2 is a diagram illustrating an exemplary DIS for which improved target positioning by using multiple terminal devices may be applicable according to an embodiment of the present disclosure.

Fig. 3 is a diagram illustrating an exemplary telecommunication system where a target carrying multiple UEs may be positioned according to an embodiment of the present disclosure.

Fig. 4 is a diagram illustrating an exemplary classification of LOS and NLOS paths for which improved target positioning by using multiple terminal devices may be applicable according to an embodiment of the present disclosure.

Fig. 5 is a diagram illustrating an exemplary simulation environment and setup for improved target positioning by using multiple terminal devices according to an embodiment of the present disclosure.

Fig. 6A to Fig. 6C are diagrams illustrating some exemplary simulation results for different UE positions according to an embodiment of the present disclosure.

Fig. 7 is a diagram illustrating an exemplary telecommunication system for improved target positioning by using multiple terminal devices according to an embodiment of the present disclosure.

Fig. 8 is a flow chart illustrating an exemplary method at a network node for positioning a target that carries a first number of terminal devices according to an embodiment of the present disclosure.

Fig. 9 is a flow chart illustrating an exemplary method at a terminal device for positioning a target that carries a first number of terminal devices comprising the terminal device according to an embodiment of the present disclosure.

Fig. 10 schematically shows an embodiment of an arrangement which may be used in a terminal device or a network node according to an embodiment of the present disclosure.

Fig. 11 is a block diagram illustrating an exemplary network node according to an embodiment of the present disclosure.

Fig. 12 is a block diagram illustrating an exemplary terminal device according to an embodiment of the present disclosure.

Detailed Description

Hereinafter, the present disclosure is described with reference to embodiments shown in the attached drawings. However, it is to be understood that those descriptions are just provided for illustrative purpose, rather than limiting the present disclosure. Further, in the following, descriptions of known structures and techniques are omitted so as not to unnecessarily obscure the concept of the present disclosure.

Those skilled in the art will appreciate that the term "exemplary" is used herein to mean "illustrative, " or "serving as an example, " and is not intended to imply that a particular embodiment is preferred over another or that a particular feature is essential. Likewise, the terms "first" and "second, " and similar terms, are used simply to distinguish one particular instance of an item or feature from another, and do not indicate a particular order or arrangement, unless the context clearly indicates otherwise. Further, the term "step, " as used herein, is meant to be synonymous with "operation" or "action. " Any description herein of a sequence of steps does not imply that these operations must be carried out in a particular order, or even that these operations are carried out in any order at all, unless the context or the details of the described operation clearly indicates otherwise.

Conditional language used herein, such as "can, " "might, " "may, " "e.g., " and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements and/or states. Thus, such conditional language is not generally intended to imply that features, elements and/or states are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without author input or prompting, whether these features, elements and/or states are included or are to be performed in any particular embodiment. Also, the term "or" is used in its inclusive sense (and not in its exclusive sense) so that when used, for example, to connect a list of elements, the term "or" means one, some, or all of the elements in the list. Further, the term "each, " as used herein, in addition to having its ordinary meaning, can mean any subset of a set of elements to which the term "each" is applied.

The term "based on" is to be read as "based at least in part on. " The term "one embodiment" and "an embodiment" are to be read as "at least one embodiment. " The term "another embodiment" is to be read as "at least one other embodiment. " Other definitions, explicit and implicit, may be included below. In addition, language such as the phrase "at least one of X, Y and Z, " unless specifically stated otherwise, is to be understood with the context as used in general to convey that an item, term, etc. may be either X, Y, or Z, or a combination thereof.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limitation of example embodiments. As used herein, the singular forms "a" , "an" , and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" , "comprising" , "has" , "having" , "includes" and/or "including" , when used herein, specify the presence of stated features, elements, and/or components etc., but do not preclude the presence or addition of one or more other features, elements, components and/or combinations thereof. It will be also understood that the terms "connect (s) , " "connecting" , "connected" , etc. when used herein, just mean that there is an electrical or communicative connection between two elements and they can be connected either directly or indirectly, unless explicitly stated to the contrary.

Of course, the present disclosure may be carried out in other specific ways than those set forth herein without departing from the scope and essential characteristics of the disclosure. One or more of the specific processes discussed below may be carried out in any electronic device comprising one or more appropriately configured processing circuits, which may in some embodiments be embodied in one or more application-specific integrated circuits (ASICs) . In some embodiments, these processing circuits may comprise one or more microprocessors, microcontrollers, and/or digital signal processors programmed with appropriate software and/or firmware to carry out one or more of the operations described above, or variants thereof. In some embodiments, these processing circuits may comprise customized hardware to carry out one or more of the functions described above. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

Although multiple embodiments of the present disclosure will be illustrated in the accompanying Drawings and described in the following Detailed Description, it should be understood that the disclosure is not limited to the disclosed embodiments, but instead is also capable of numerous rearrangements, modifications, and substitutions without departing from the present disclosure that as will be set forth and defined within the claims.

Further, please note that although the following description of some embodiments of the present disclosure is given in the context of 5G New Radio (5G NR) , the present disclosure is not limited thereto. In fact, as long as improved target positioning by using multiple terminal devices are involved, the inventive concept of the present disclosure may be applicable to any appropriate communication architecture, for example, to Global System for Mobile Communications (GSM) /General Packet Radio Service (GPRS) , Enhanced Data Rates for GSM Evolution (EDGE) , Code Division Multiple Access (CDMA) , Wideband CDMA (WCDMA) , Time Division -Synchronous CDMA (TD-SCDMA) , CDMA2000, Worldwide Interoperability for Microwave Access (WiMAX) , Wireless Fidelity (Wi-Fi) , Long Term Evolution (LTE) , future 6G systems, etc. Therefore, one skilled in the arts could readily understand that the terms used herein may also refer to their equivalents in any other infrastructure. For example, the term "terminal device" used herein may refer to a UE, a mobile device, a mobile terminal, a mobile station, a user device, a user terminal, a wireless device, a wireless terminal, an IoT device, a vehicle, or any other equivalents. For another example, the term "network node" used herein may refer to a base station, a base transceiver station, an access point, a hot spot, a NodeB (NB) , an evolved NodeB (eNB) , a gNB, a DoT, a network element, a network function, or any other equivalents.

Further, the term "syncretic processing" or "filtering" may be used interchangeably hereinafter.

In some embodiments of the present disclosure, cellular-based indoor positioning in 5G networks are discussed, and an enhanced indoor positioning scheme is proposed. However, the present disclosure is not limited thereto. For example, the positioning scheme is also applicable to outdoor positioning scenarios.

In some embodiments, the key ideas can be summarized as below:

- Consider the case that the positioned target (which could be either a human being or an object) carries two (or even more) 5G UEs, each of which can be a regular 5G UE, or a RedCap (reduced capability) 5G UE, or a further simplified mMTC-type UE.

√ RedCap UE (e.g., wearable devices, industrial sensors) has been introduced for 5G systems in 3GPP Rel-17.

√ In practice, two UEs in hand for a human are more and more popular. Also, once there exists the positioning service requirement on a target, two (or even more) UEs can be deployed intentionally on this target in advance, especially when this target is an object.

- Upon exploiting a DIS and applying OTDoA positioning scheme to the DIS, each of two (or even more) 5G UEs, which are carried by the positioned target, can result in RSTDs upon the corresponding PRS ToA measurements. If the RSTD resulted by PRS transmissions from the reference access point (which is a digital headend in a DIS for example) and a neighboring access pointi (which is another digital headend in a DIS for example) is denoted as RSTD _0, i, then, for every available i, the RSTD _0, i is obtained by appropriately doing "syncretic processing" (or "filtering" ) on the ToAs measured by two (or even more) 5G UEs.

√ In some embodiments, to be able to apply OTDoA to the DIS, the precondition is to utilize the method taught in the international PCT application (PCT/CN2022/093880) . Note that, compared with OTDoA, UTDoA is not so suitable for large-scale commercial deployment (because SRS resources for different UEs need to be orthogonal) and has worse positioning performance.

√ In some embodiments, the syncretic processing on the ToAs measured by multiple UEs, used to get RSTD _0, i (for every available i) , is the key to enhance the positioning accuracy and integrity. Specifically, the proposed ways of syncretic processing include (but not limited to) :

i. In some embodiments, the mainly recommended way of syncretic processing is arithmetic average processing. Specifically, either a uniform average or a weighted average with the weights being designed upon "path PRS RSRPs" can be performed.

"The measurement and reporting for path-based PRS RSRP" , introduced in 3GPP since newly completed Rel-17, may be exploited here.

ii. Further, among J (J≥2) 5G UEs in one positioned target, if there exist at least one "all-LOS-path UE" whose ToA measurements are all LOS-path resulted ToA measurements, it is recommended to select the ToA measurements of one "all-LOS-path UE" as the output of the syncretic processing. This way can be viewed as prioritizing LOS-resulted ToA with the prioritization granularity being UE.

"The detection and indication of LOS propagation path" , introduced in 3GPP since newly completed Rel-17, may be exploited here.

iii. In addition, to cover all reasonable ways, the following ways can be considered as options (which can be classified as prioritizing LOS-resulted ToA with the prioritization granularity being ToA) :

iii. 1) Using two 5G UEs as the example, if the ToAs measured by these two UEs for PRS transmissions from an available access point are one LOS-resulted ToA and one NLOS-resulted ToA, then the ToA from the considered access point to the positioned target is selected as that LOS-resulted ToA.

This optional way of syncretic processing will achieve performance gain only when "the two 5G UEs are located closely enough" and "NLOS-resulted ToA offset is large enough" . When the two 5G UEs are fixed at the positioned target, it is easy to make them be located closely enough; of course, in this case, the occurrence probability of the event that "the ToAs measured by the two UEs for PRS transmissions from an available access point are one LOS-resulted ToA and one NLOS-resulted ToA" is small.

iii. 2) Using two 5G UEs as the example, if the ToAs measured by these two UEs for PRS transmissions from an available access point are two LOS-resulted ToAs, then the ToA from the considered access point to the positioned target is selected as the one which has larger LOS-path PRS RSRP.

This optional way of syncretic processing will achieve performance gain only when "the two 5G UEs are located closely enough" . When the two 5G UEs are fixed at the positioned target, it is easy to make them be located closely enough.

√ In some embodiments, the information about the association between the positioned target and its carried two (or even more) 5G UEs need to be signaled over some certain interface. Specifically, three optional ways can be considered; more details can be found in embodiments described below with reference to Fig. 7.

- The abovementioned proposal is also applicable for the following indoor positioning scenarios:

√ Exploit a DIS to do indoor positioning and apply another "relative time difference" based positioning scheme (e.g., UTDoA) to the DIS.

√ Exploit access points other than DIS (e.g., outdoor BSs or indoor DAS) to do indoor positioning and apply one "relative time difference" based positioning scheme (e.g., OTDoA/UTDoA) to the corresponding access points.

- Further, the use of the abovementioned proposal can also be naturally extended to do outdoor positioning, when applying one "relative time difference" based positioning scheme (e.g., OTDoA/UTDoA) to outdoor BSs.

In some embodiments, J (J≥2) 5G UEs in one positioned target are utilized to improve the positioning accuracy and integrity for cellular-based positioning.

- Performance enhancement: Upon exploiting a DIS and applying one "relative time difference" based positioning scheme (e.g., OTDoA/UTDoA) to the DIS, for every available measurement of time difference (which will be further utilized to calculate the position of the target) , it is obtained by appropriately doing syncretic processing on the corresponding J groups of ToA measurements generated by J UEs, thus enhancing the positioning accuracy and integrity.

- Broad applicability: Although the focused scenario is indoor positioning using DIS, the solution can also be used for indoor positioning without DIS and for outdoor positioning.

Further, the methods proposed in the international PCT application (PCT/CN2022/093880) can be used in the solution according to some embodiments of the present disclosure to enable the usage of OTDoA in a DIS, so that a more accurate and trustworthy 5G indoor positioning may be achieved.

In the embodiments described below, OTDoA is used as the example of the used "relative time difference" based positioning scheme, and an example scenario where three access points are available to reach the positioned target via wireless signal transmissions and two UEs are carried by the positioned target is considered. This example is illustrated in Fig. 3.

Fig. 3 is a diagram illustrating an exemplary telecommunication system 30 where a target 101 carrying multiple UEs 100-1 and 100-2 may be positioned according to an embodiment of the present disclosure. As shown in Fig. 3 and also mentioned above, the target 101 (which could be a human being or an object) may carry more than one UEs (or terminal devices) , such as a UE a 100-1 and a UE b 100-2 (collectively, the UEs 100) , and at least three access points, such as a reference access point 105-1, an access point 1 105-2, and an access point 105-3 (collectively, the access points 105) , may transmit downlink signals for positioning, for example, PRS. However, the present disclosure is not limited thereto. In some other embodiments, the access points 105 may receive, from the UEs 100, uplink signals for positioning, such as SRS. In some other embodiments, the number of the UEs and/or the number of the access points may be different from those shown in Fig. 3.

In the illustrated example, to enhance the positioning accuracy and integrity, RSTD _0, 1 (i.e., the time difference between the reference access point 105-1 and the access point 1 105-2) and RSTD _0, 2 (i.e., the time difference between the reference access point 105-1 and the access point 2 105-3) may be obtained by doing syncretic processing or filtering on the corresponding 2 groups of ToA measurements (i.e., {ToA _0, _a, ToA _1, a, ToA _2, a} and {ToA _0, b, ToA _1, b, ToA _2, b} ) .

In some embodiments, "the measurement and reporting for path PRS RSRP" and "the detection and indication of LOS propagation path" , introduced in 3GPP Rel-17, may be exploited in the proposed syncretic processing.

In Rel-16, an RSRP measured and reported by a UE corresponds to the total power of all propagation paths. However, the direction of the LOS path is the main concern here, and therefore it has been agreed in Rel-17 that the UE can measure the power of the first path and up to 8 additional paths respectively. In another words, a new path-based RSRP measurement has been introduced in Rel-17.

With the support of "the measurement and reporting for path PRS RSRP" , in Rel-17, rich multipath reporting is further utilized to do LOS/NLOS classification. A very simple classifier can for instance be constructed based on the fact that, in LOS conditions, the power of the first path corresponds to the first peak in the power-delay profile; in another words, the power of the first path is greater than that of any other paths if there exists LOS path over the corresponding wireless link, as shown in Fig. 4.

For ease of description, denote {ToA ₀, ToA ₁, ToA ₂} as the ToA values after the syncretic processing (i.e., the ToA values used for determining the position of the target) . In the following, using the illustrated example shown in Fig. 3, the syncretic processing may be performed as follows.

In some embodiments, if all of three ToAs measured by one UE (which is assumed to be UE a 100-1 as an example) are LOS-path resulted ToA measurements, and one or more of three ToAs measured by the other UE (which is assumed to be UE b 100-2 in the example) are NLOS-path resulted ToA measurements:

The recommended way: {ToA ₀, ToA ₁, ToA ₂} = {ToA _0, a, ToA _1, a, ToA _2, a} .

[This corresponds to the way ii) of syncretic processing described above (i.e., prioritizing LOS-resulted ToA with the prioritization granularity being UE) . ]

In some embodiments, if at least one of three ToAs measured by UE a 100-1 is NLOS-path resulted ToA measurement, and at least one of three ToAs measured by UE b 100-2 is NLOS-path resulted ToA measurement:

The recommended way:

ToA ₀ = μ ₀ ×ToA _0, a + v ₀ ×ToA _0, b

ToA ₁ = μ ₁ ×ToA _1, a + v ₁ ×ToA _1, b

ToA ₂ = μ ₂ ×ToA _2, a + v ₂ ×ToA _2, b

[This corresponds to the way i) of syncretic processing described above (i.e., arithmetic average processing) . ]

If a uniform average is considered, then

μ ₀ = v ₀ = 1/2

μ ₁ = v ₁ = 1/2

μ ₂ = v ₂ = 1/2

If a weighted average with the weights being designed upon "path PRS RSRPs" (denoted as P _0, a, P _0, b, P _1, a, P _1, b, P _2, a, P _2, b) is considered, then

Further, the 2 ^nd way that could be considered is provided as follows.

A specific example is used to give an illustration. In this example, it is assumed that "ToA _0, a is NLOS-path resulted and both of {ToA _1, a, ToA _2, a} are LOS-path resulted" , "ToA _1, b is NLOS-path resulted and both of {ToA _0, b, ToA _2, b} are LOS-path resulted" , and "P _2, a (LOS-path PRS RSRP resulted by the PRS transmission from the access point 2 105-3 to UE a 100-1) is larger than P _2, b (LOS-path PRS RSRP resulted by the PRS transmission from access point 2 105-3 to UE b 100-2) " . Then,

ToA ₀ = ToA _0, b

ToA ₁ = ToA _1, a

ToA ₂ = ToA _2, a

[This corresponds to the way iii) of syncretic processing described above (i.e., prioritizing LOS-resulted ToA with the prioritization granularity being ToA) . ]

In some embodiments, this optional way may be used only when "the two 5G UEs are located closely enough" , which can be implemented if the two 5G UEs are fixed at the positioned target. This is because, if the two 5G UEs are not located closely enough, with this way, there generally will not exist a location in real world whose geographical coordinates can have the corresponding ToA measurements be equal to or approximately equal to those prioritized selection of LOS-resulted ToAs.

Upon the above example, a further analysis can be made: Since ToA ₀ = ToA _0, b, ToA ₁ = ToA _1, a, ToA ₂ = ToA _2, a, if the UE a 100-1 is viewed as the base UE for position estimation, the activity that "the LOS-path resulted ToA _0, b is selected as ToA ₀" is actually equivalent to adding an NLOS-resulted ToA offset over the link between the base UE and the corresponding access point. If this equivalent NLOS-resulted ToA offset is not smaller than the original NLOS-resulted ToA offset of ToA _0, a, the performance shall be worse than "selecting ToA _0, a to be ToA ₀ so that all ToA values come from one same UE" (i.e., this optional way of syncretic processing shall not achieve positioning performance gain. )

In some embodiments, if all of three ToAs measured by UE a 100-1 are LOS-path resulted ToA measurements, and all of three ToAs measured by UE b 100-2 are also LOS-path resulted ToA measurements:

The recommended way: {ToA ₀, ToA ₁, ToA ₂} = {ToA _0, a, ToA _1, a, ToA _2, a} or {ToA _0, _b, ToA _1, b, ToA _2, b} .

Further, the 2 ^nd way that could be considered:

ToA ₀ = μ ₀ ×ToA _0, a + v ₀ ×ToA _0, b

ToA ₁ = μ ₁ ×ToA _1, a + v ₁ ×ToA _1, b

ToA ₂ = μ ₂ ×ToA _2, a + v ₂ ×ToA _2, b

If a uniform average is considered, then

μ ₀ = v ₀ = 1/2

μ ₁= v ₁= 1/2

μ ₂ = v ₂= 1/2

At some certain time period, "the conditions of all three wireless channels from 3 access points 105 to UE a 100-1" and "the conditions of all three wireless channels from 3 access points 105 to UE b 100-2" may be quite similar. Tn this case, even if the positioning accuracy will not be significantly improved, the proposed "syncretic processing for the ToAs measured by multiple UEs" will also enhance the positioning "integrity" , because certain measurement uncertainty/error cannot be always avoided at one or all of these two UEs under any given channel conditions.

Besides positioning accuracy, another important performance metric for positioning is "integrity" , which is a measure of the trust in the achieved positioning accuracy (in another words, a measure of the trust that can be placed in the correctness of positioning result) .

Specifically, the metric of positioning integrity was introduced in 3GPP Rel-17 with being applicable for only A-GNSS positioning; now, it has been officially introduced to be applicable for all the other cellular positioning schemes in 3GPP Rel-18.

When the scenario is indoor positioning using DIS, an access point is a digital headend (e.g., a DoT) and the number of access points available for any one target is generally larger than three.

In practice, if the positioned target is an object but not a person, it is easy to let more than two UEs be carried by the positioned object. Furthermore, when the positioned target is a person, if wearable devices (which can be implemented in the form of 5G RedCap UEs) are utilized, the number of UEs carried by the positioned person could also be easily larger than two.

With the scheme proposed in some embodiments of the present disclosure, as the number of UEs carried by the positioned target is larger, the enhancement on positioning performance is more obvious.

Next, a simulation environment and setup will be described with reference to Fig. 5.

Fig. 5 is a diagram illustrating an exemplary simulation environment and setup for improved target positioning by using multiple terminal devices according to an embodiment of the present disclosure. Here, the indoor positioning using indoor access points is used as the example.

It is assumed that two UEs are carried by the positioned target 101. To well mimic a positioned person or object that carries two (or even more) regular/RedCap/mMTC-type 5G UEs, the size of the positioned target 101 is set as 1m length × 1m width × 1m height. In the simulations, without loss of generality, the 2-dimensional projection of the "center" location of positioned target is set as (0, 0) , which means the x-and y-coordinates of 4 vertices of the 2-dimensional projection of positioned target 101 are (-0.5, -0.5) , (-0.5, 0.5) , (0.5, 0.5) , and (0.5, -0.5) .

Besides the serving access point 105-1 (which will be used as the reference access point for positioning) , it is assumed that there are 3 other reachable access points, that is, the access point 1 105-2, the access point 2 105-3, and the access point 3 105-4 (collectively, the access points 105) . In a deployment of indoor access points, the distance between a user and the serving access point 105-1, the distance between a user and any one of another reachable access points 105-2/105-3/105-4, and the distance between any two neighboring access points 105 are generally smaller than 50m. With the 2-dimensional projections of the geographical coordinates of 4 reachable access points 105 being within [-50, 50] for either x-or y-coordinates, the locations of 4 reachable access points 105 can be randomly distributed without obvious un-reasonability of the abovementioned distances.

Several different setups of the locations of 4 reachable access points 105 have been considered in the simulations, they all lead to similar simulation results.

In particular, simulation results of positioning performance are presented by using the example locations of 4 reachable access points 105 illustrated in Fig. 5. This case is actually an unfriendly case, where the positioned target 101 is at the cell edge of the serving cell. In another words, to verify the effectiveness of the proposed scheme strictly, a more challenging case is chosen to present simulation results.

For 4 reachable access points 105 and two UEs carried by the positioned target 101, when one "relative time difference" based positioning scheme (e.g., OTDoA/UTDoA) is used, there are total 4×2 = 8 ToA measurements obtained at the two UEs. In the simulations, OTDoA positioning scheme is used.

For the friendly case where all the 4 ToAs measured by one UE are LOS-path resulted ToA measurements and one or more of the 4 ToAs measured by the other UE are NLOS-path resulted ToA measurement (s) , the recommended way of syncretic processing (i.e., prioritizing LOS-resulted ToA with the prioritization granularity being UE) will definitely achieve performance gain, through selecting the "all-LOS-path UE" to perform positioning; thus, this case will not be simulated.

In the simulations, the most unfriendly case where not only there is no "all-LOS-path UE" but also all the 8 ToA measurements obtained at the two UEs are NLOS-path resulted measurements will be considered. Furthermore, the performance of positioning accuracy will be evaluated in the following two types of configurations:

1) The locations of the two UEs 100 carried by the positioned target 101 are configured as some fixed positions within the space with 1m length × 1m width × 1m height. For example, the 3-dimensional coordinates of two UEs are configured as (-0.5, -0.5, 1) and (0.5, 0.5, 1) .

For this type of configuration, if there are m (m ≤ 8) NLOS-path resulted ToA measurement (s) , for each NLOS-path resulted ToA measurement (which can be modeled as "LOS-path resulted ToA plus a NLOS-resulted ToA offset" ) , the corresponding NLOS-resulted ToA offset will be randomly generated within a given range [NLOSToAoffsetRange_start, NLOSToAoffsetRange_end] . Then, the positioning accuracy is firstly evaluated under each group of given realization of "m NLOS-resulted ToA offset (s) " . Finally, the averaged positioning accuracy is obtained via doing average over all the NumofNLOSToAoffsetgroups of realizations of "m NLOS-resulted ToA offset (s) " .

In the simulations, the value of NLOSToAoffsetRange_endis set as some ToA offsets which can make propagation distance offset be n times of the half-length of the positioned target, with n being equal to 1, 2, and 6. In addition, NLOSToAoffsetRange_start is set as half of NLOSToAoffsetRange_end.

In the simulations, NumofNLOSToAoffset = 10000.

2) The locations of the two UEs 100 carried by the positioned target 101 are configured as randomly generated positions within the space with 1m length × 1m width × 1m height.

For any one group of given realization of "the positions of two UEs 100 carried by the positioned target 101" , "the same methodology as that for the above configuration type 1) " is used to get one realization of averaged positioning accuracy; then, the eventually averaged positioning accuracy is obtained via doing average over all the NumofUEpositions groups of realizations of "the positions of two UEs 100 carried by the positioned target 101" .

In the simulations, NumofUEpositions = 10000.

It is noticed that, even if i) the used "relative time difference" based positioning scheme (e.g., OTDoA/UTDoA) is given and ii) the setups for the number of the UEs carried by the positioned target, the location of the positioned target, the number and the locations of the reachable access points 105 are given, the specific values of simulated positioning accuracy will still change when varying the specific position estimation algorithm (such as 3-dimensional Taylor Series based algorithm, Chan and Ho′s algorithm, etc. ) .

Thus, in some embodiments of the present disclosure, the performance results are represented by illustrating relative performance difference between the existing and proposed positioning schemes. Specifically, the metric "percentage of improved average positioning accuracy" is considered, which is defined as (B -A) /B if A and B are denoted as positioning accuracy for the proposed and the existing schemes respectively.

For positioning accuracy (which is generally calculated as the "distance deviation" from the real position of the positioned target) , the value is smaller, the performance is better. Thus, if the value of positioning accuracy of the proposed scheme (i.e., A) is smaller than that of the existing scheme (i.e., B) so that (B -A) /B is a positive percentage, the proposed scheme has better positioning performance (i.e., the proposed scheme can achieve performance improvement) .

First, the simulation results obtained with the configuration type 1) described above will be examined, where the locations of the two UEs carried by the positioned target are configured as some fixed positions within the space with 1m length × 1m width × 1m height.

Three typical groups of "fixed positions" for the two UEs carried by the positioned target are used: { (-0.5, -0.5, 1) ; (0.5, 0.5, 1) } , { (0.5, -0.5, 1) ; (0.5, 0.5, 1) } , { (-0.5, 0.5, 1) ; (0.5, 0.5, 1) } .

The following tables presents simulations results when all the 8 ToA measurements obtained at the two UEs are NLOS-path resulted measurements.

In the simulations, the recommended way of syncretic processing for this case is used (i.e., arithmetic average processing) ; specifically, a uniform average is considered.

As already described above, to get reliable results that have universal validity, the positioning accuracy is obtained via doing average over NumofNLOSToAoffset= 10000 groups of realizations of "8 NLOS-resulted ToA offsets" .

With the configuration shown in Fig. 6A, the simulation result is provided in Table 1 below.

Table 1

With the configuration shown in Fig. 6B, the simulation result is provided in Table 2 below.

Table 2

With the configuration shown in Fig. 6C, the simulation result is provided in Table 3 below.

Table 3

It can be seen that, for given locations of the reachable access points and the positioned target, such as the "unfriendly" example of the locations considered in the simulations (where the positioned target is at the cell edge of the serving cell) , different configurations for the "fixed positions" of the two UEs carried by the positioned target will generally result in different performance gains.

For the above simulations results, when the configuration for the "fixed positions" of the two UEs are { (-0.5, 0.5, 1) ; (0.5, -0.5, 1) } , the performance gain is larger than those resulted from other 2 configurations for the "fixed positions" of the two UEs; the corresponding justification is: relatively, for this "fixed positions" configuration of the two UEs, the internal distance between the two UEs is larger and the position distribution of the two UEs make them have more uniform/ergodic signal propagation paths with the 4 reachable access points.

It can be observed that when n is larger (i.e., the averaged NLOS-resulted ToA offset is larger) , the performance gain is smaller.

Next, the simulation results obtained with the configuration type 2) described above will be examined, where the locations of the two UEs carried by the positioned target are configured as randomly generated positions within the space with 1m length × 1m width × 1m height.

The following Table 4 presents simulations results when all the 8 ToA measurements obtained at the two UEs are NLOS-path resulted measurements.

Table 4

In the simulations, the recommended way of syncretic processing for this case (i.e., arithmetic average processing) is used; specifically, a uniform average is considered.

As already described above, to get reliable results that have universal validity, the positioning accuracy is obtained via i) firstly doing average over NumofNLOSToAoffset = 10000 groups of realizations of "8 NLOS-resulted ToA offsets" for any one group of given realization of "the positions of two UEs carried by the positioned target" and ii) then doing average over all the NumofUEpositions = 10000 groups of realizations of "the positions of two UEs carried by the positioned target" .

A summary upon simulation results for the most "unfriendly" case is provided as follows:

- Good gains for positioning accuracy can be achieved, if two UEs are put at the well-designed "fixed positions" within/on the positioned target; this can be easily implemented especially when the positioned target is an object or a human being who need special care (e.g., a wheelchair-bound old/sick person) .

- Even if the positions of two UEs carried by the positioned target are not fixed, (e.g., if the positioned target is a normal human being while the two UEs carried by this person are a mobile phone and a smart bracelet) , the improvement on the positioning accuracy can still be achieved.

- The performance gains shown above are obtained under the most "unfriendly" case where the positioned target is at the cell edge of the serving cell and all the ToA measurements obtained at the two UEs are NLOS-path resulted measurements. For more friendly cases, the performance gains will be larger, no matter whether the multiple UEs carried by the positioned target have fixed or random positions.

Fig. 7 is a diagram illustrating an exemplary telecommunication system 70 for improved target positioning by using multiple terminal devices according to an embodiment of the present disclosure. As shown in Fig. 7, the system 70 may comprise a positioned target 101 carrying two or more terminal devices 100 (e.g., a UE a 100-1 and a UE b 100-2, collectively, the UEs or the terminal devices 100) , one or more access points 105 (e.g., an access point #1 105-1, an access point #2 105-2, ..., and an access point #N 105-5, collectively, the access points 105) , an AMF 710, an LMF 720, a GMLC 730, and an LCS server 740. As already described above, the information about the association between the positioned target 101 and its carried two (or even more) 5G UEs 100 need to be signaled over some certain interface in some embodiments.

Specifically, three optional ways can be considered when implementing the proposed scheme:

Option 1: The association information is only signaled from location service (LCS) server 740 to Location Management Function (LMF) 720, via the interface between LCS server 740 and Gateway Mobile Location Center (GMLC) 730 (i.e., the interface ① in Fig. 7) , the interface between GMLC 730 and Access and Mobility Management Function (AMF) 710 (i.e., the interface ② in Fig. 7) , and the interface between AMF 710 and LMF 720 (i.e., the interface ③ in Fig. 7) .

In this way, using OTDoA as the example of the used "relative time difference" based positioning scheme, the following facts can be observed:

The syncretic processing on the ToAs measured by multiple UEs 100 (of which the result will be used to generate RSTD _0, i for every available i) is performed at LMF 720, and the proposed scheme is transparent to access points 105 and UEs 100.

However, each of two (or even more) 5G UEs 100 carried by the positioned target 101 needs to feed back the ToA measurements over the air interface between it and its serving access point (s) (e.g., the access point #1 105-1) , and the number of ToA measurements sent from the involved access points (e.g., the access point #1 105-1) to LMF 720 is proportional to the number of UEs 100 carried by the target 101.

Option 2: On top of the abovementioned Option 1, the association information is further signaled to access points 105 (e.g., the access point #1 105-1) , via the interface between AMF 710 and access points 105 (i.e., the interface ④ in Fig. 7) .

The syncretic processing on the ToAs measured by multiple UEs 100 (of which the result will be used to generate RSTD _0, i for every available i) can be performed at access point (s) 105, and the proposed scheme is just transparent to UEs 100.

If the involved access points 105 are digital headends in a DIS, the syncretic processing is actually performed at the corresponding BBU.

While each of two (or even more) 5G UEs 100 carried by the positioned target 101 still needs to feed back the ToA measurements over the air interface, the number of ToA measurements sent from the involved access points 105 to LMF 720 is smaller.

Option 3: On top of the abovementioned Option 2, the association information is further signaled to UEs, via the interface between UEs 100 and their serving access point (s) 105 (i.e., the interface ⑤ in Fig. 7) .

The syncretic processing on the ToAs measured by multiple UEs 100 (of which the result will be used to generate RSTD _0, i for every available i) can be performed at one of two (or even more) 5G UEs 100 carried by the positioned target 101, where UE aggregation is utilized to enable other UEs to send their measurements to the chosen one UE (e.g., the UE a 100-1) via using a non-standardized UE-UE interconnection (e.g., WiFi, Bluetooth) . UE aggregation has been introduced into 3GPP NR standardization in Rel-18.

With this option, only one 5G UE carried by the positioned target 101 feeds back the "syncretized" (or called "filtered" ) ToA measurements over the air interface, and the number of ToA measurements sent from the involved access points 105 to LMF 720 is as small as that with Option 2.

This option is preferred when the two (or even more) 5G UEs 100 carried by the positioned target 101 have different capabilities.

For example, if the positioned target 101 carries two UEs 100 where one is an energy-limited 5G UE (e.g., the UE b 100-2) and the other is a regular 5G UE (e.g., the UE a 100-1) , it is beneficial to reduce uplink feedback from that energy-limited 5G UE; thus, the regular 5G UE is chosen to perform syncretic processing and transmit the syncretized ToA measurements in uplink.

In some embodiments, the way for determining whether multiple UEs are really carried by the positioned target is provided.

When the positioned target is an object, it is possible that one of J (J≥ 2) 5G UEs is accidentally lost although the probability of this kind of event is small. When the positioned target is a human being, it is possible that this person sometimes forgets to carry one of J (J≥ 2) 5G UEs even if the probability of this kind of event is not large. Thus, an appropriate way to determine whether J (J≥ 2) UEs are really carried by the positioned target is needed.

In particular, using OTDoA as the example of the used "relative time difference" based positioning scheme, the designed way includes the following two steps:

Step 1: Check whether the serving cell IDs of the JUEs are the same one.

- When the abovementioned association information is signaled via

Option

1 or 2 described above (i.e., the proposed scheme is transparent to UEs) , this check is performed at the network side.

- When the abovementioned association information is signaled via Options 3 described above, this check is performed at the UE side also with the help of UE aggregation.

Step 2: After the check at Step 1 is passed, check whether the measured PRS RSRPs of the JUEs for "any one given PRS resource which can be received and measured by these J UEs" have enough small relative differences.

- Inspired by mature mechanism used in Rel-16 Radio Resource Management (RRM) relaxation for 5G UE power saving (where the comparison between "variation in RSRP for a time period" and a threshold is used to determine whether a UE′s position does not have variation or only has small variation) , here, comparing "RSRP difference between two UEs" and a threshold is considered to determine whether these two UEs are close enough.

- About the abovementioned "any one given PRS resource which can be received and measured by these J UEs" : i) If access points are outdoor gNBs, generally it is a wideband PRS resource and can be associated with one outdoor gNB (which is either the serving gNB or one neighboring gNB) ; ii) If access points are digital headends of a DIS, upon the international PCT application (PCT/CN2022/093880) , it is a subband PRS resource and can be associated with one digital headend.

- In the implementation, the serving cell will configure PRS RSRP measurement for the first PRS occasion (i.e., for the first time window of PRS measurement) .

- Depending on specific implementation, the check can be performed for only one given PRS resource which can be received and measured by these J UEs (e.g., the wideband PRS resource used by the serving cell if access points are outdoor gNBs, or the subband PRS resource that causes strongest RSRP if access points are digital headends of a DIS) , or the check can be performed for W (W≥ 2) given PRS resources which can be received and measured by these J UEs.

- About whether "the place at which the check operation is performed" is at the network side or at the UE side, similar as what described in the above Step 1, it depends on which option described above is used to signal the information about the association between the positioned target and its carried J (J≥ 2) 5G UEs.

Fig. 8 is a flow chart of an exemplary method 800 at a network node for positioning a target that carries a first number of terminal devices according to an embodiment of the present disclosure. In some embodiments, the first number is greater than 1. The method 800 may be performed at a network node (e.g., the access point 105-1 shown in Fig. 3 or the LMF 720 shown in Fig. 7) . The method 800 may comprise step S810 and Step S820. However, the present disclosure is not limited thereto. In some other embodiments, the method 800 may comprise more steps, less steps, different steps, or any combination thereof. Further the steps of the method 800 may be performed in a different order than that described herein. Further, in some embodiments, a step in the method 800 may be split into multiple sub-steps and performed by different entities, and/or multiple steps in the method 800 may be combined into a single step.

The method 800 may begin at step S810 where a set of filtered measurements may be determined based on at least a first number of sets of original measurements that are measured by a same RAT, each of the first number of sets being associated with a corresponding one of the first number of terminal devices.

At step S820, a position of the target may be determined based on at least the set of filtered measurements.

In some embodiments, the step of determining the position of the target may comprise: determining the position of the target by using a positioning scheme applicable to a single one of the first number of terminal devices while the set of original measurements, which is associated with the single terminal device and is input to the positioning scheme, is replaced with the set of filtered measurements. In some embodiments, the step of determining the set of filtered measurements may comprise: determining each member of the set of filtered measurements as a weighted average of a first number of original measurements, each of the first number of original measurements belonging to a set of original measurements associated with a corresponding one of the first number of terminal devices.

In some embodiments, when all of original measurements associated with a second number of terminal devices from the first number of terminal devices are LOS measurements, the original measurements associated with only one of the second number of all-LOS-path terminal device may be selected to determine the set of filtered measurements, and a weight associated with an original measurement may be determined as follows: 1, when the original measurement is selected; and/or 0, when the original measurement is not selected. In some embodiments, when all of original measurements associated with a second number of terminal devices from the first number of terminal devices are LOS measurements, the original measurements associated with all of the second number of all-LOS-path terminal devices may be selected to determine the set of filtered measurements, and a weight associated with an original measurement may be determined as follows: a ratio of 1 to the second number, when the original measurement is selected; and/or 0, when the original measurement is not selected.

In some embodiments, when all of original measurements associated with a second number of terminal devices from the first number of terminal devices are LOS measurements, the original measurements associated with all of the second number of all-LOS-path terminal devices may be selected to determine the set of filtered measurements, and a weight associated with an original measurement may be determined as follows: a ratio of an RSRP corresponding to the original measurement to a sum of all RSRPs corresponding to the selected original measurements used for determining a corresponding filtered measurement, when the original measurement is selected; and/or 0, when the original measurement is not selected. In some embodiments, when at least one original measurement for each of the first number of terminal devices is an NLOS measurement, a weight associated with an original measurement may be determined as a ratio of 1 to the first number. In some embodiments, when at least one original measurement for each of the first number of terminal devices is an NLOS measurement, a weight associated with an original measurement may be determined as a ratio of an RSRP corresponding to the original measurement to a sum of all RSRPs corresponding to the first number of original measurements used for determining a corresponding filtered measurement.

In some embodiments, when at least one original measurement for each of the first number of terminal devices is an NLOS measurement, and when there are one or more LOS measurements among the original measurements used for determining a corresponding filtered measurement, a weight associated with an original measurement used for determining the corresponding filtered measurement may be determined as follows: 1, when the original measurement is the only one LOS measurement among the original measurements used for determining the corresponding filtered measurement, or when the original measurement is one of multiple LOS measurements among the original measurements used for determining the corresponding filtered measurement and has an RSRP greater than RSRPs corresponding to other original measurements that are LOS measurements and used for determining the corresponding filtered measurement; and/or 0, otherwise.

In some embodiments, when at least one original measurement for each of the first number of terminal devices is an NLOS measurement, and when there is no LOS measurement among the original measurements used for determining a corresponding filtered measurement, a weight associated with an original measurement used for determining the corresponding filtered measurement may be determined as a ratio of 1 to the first number. In some embodiments, when at least one original measurement for each of the first number of terminal devices is an NLOS measurement, and when there is no LOS measurement among the original measurements used for determining a corresponding filtered measurement, a weight associated with an original measurement used for determining the corresponding filtered measurement may be determined as a ratio of an RSRP corresponding to the original measurement to a sum of all RSRPs corresponding to the first number of original measurements used for determining the corresponding filtered measurement. In some embodiments, the first number of terminal devices may be separated from each other by a distance less than a first threshold.

In some embodiments, at least three members in each set from the first number of sets of original measurements may be ToA measurements, from which at least three members in the set of filtered measurements, which are filtered ToA measurements, may be determined. In some embodiments, each of at least three ToAs associated with a terminal device may be measured on a reference signal transmitted between the terminal device and a corresponding one of at least three access points, wherein the at least three access points may comprise at least a reference access point, a first access point, and a second access point.

In some embodiments, a first filtered RSTD for the reference access point and the first access point and a second filtered RSTD for the reference access point and the second access point may be calculated as follows: the first filtered RSTD may be calculated as a difference between a filtered ToA associated with the first access point and a filtered ToA associated with the reference access point; and/or the second filtered RSTD may be calculated as a difference between a filtered ToA associated with the second access point and a filtered ToA associated with the reference access point.

In some embodiments, the positioning scheme may comprise at least a ranging measurement based positioning scheme. In some embodiments, the positioning scheme comprises at least one of: DL-TDoA; UL-TDoA; and Multi-RTT. In some embodiments, an access point may be a digital headend when a digital indoor system is used to do indoor positioning. In some embodiments, the network node may be at least one of: an LMF; and an access point.

In some embodiments, before the step of determining the set of filtered measurements, the method 800 may further comprise: receiving, from another network node, association information that indicates at least one of: that the target is associated with the first number of terminal devices; and that the set of filtered measurements is to be determined based on the first number of sets of original measurements associated with the first number of terminal devices. In some embodiments, when the network node is an LMF, the association information may be received from an LCS server via a GMLC and an AMF. In some embodiments, when the network node is an access point, the association information may be received from an LCS server via a GMLC and an AMF. In some embodiments, the associated information may be transmitted by the LCS server to the LMF.

In some embodiments, before the step of determining the set of filtered measurements, the method 800 may further comprise: determining whether all of the first number of terminal devices are co-located with the target or not. In some embodiments, the step of determining whether all of the first number of terminal devices are co-located with the target or not may comprise: determining whether the first number of terminal devices are associated with a same serving cell ID; and determining whether RSRPs measured by the first number of terminal devices over one or more same RS resources have relative differences from each other less than a threshold.

In some embodiments, when compared with using one terminal device for positioning a target, the utilization of the first number of terminal devices and the corresponding filtered measurements may improve the positioning scheme in terms of at least one of positioning accuracy and positioning integrity.

In some embodiments, reference signals that are measured may comprise at least one of: a PRS; and an SRS. In some embodiments, the RAT may comprise one of: NR; LTE; Wi-Fi; and Bluetooth.

Fig. 9 is a flow chart of an exemplary method 900 at a terminal device for positioning a target that carries a first number of terminal devices comprising the terminal device according to an embodiment of the present disclosure. In some embodiments, the first number is greater than 1. The method 900 may be performed at a terminal device (e.g., the UE a 100-1 or the UE b 100-2 shown in Fig. 3) . The method 900 may comprise step S910 and Step S920. However, the present disclosure is not limited thereto. In some other embodiments, the method 900 may comprise more steps, less steps, different steps, or any combination thereof. Further the steps of the method 900 may be performed in a different order than that described herein. Further, in some embodiments, a step in the method 900 may be split into multiple sub-steps and performed by different entities, and/or multiple steps in the method 900 may be combined into a single step.

The method 900 may begin at step S910 where a set of filtered measurements may be determined based on at least a first number of sets of original measurements that are measured by a same RAT, each of the first number of sets being associated with a corresponding one of the first number of terminal devices.

At step S920, a position of the target may be determined based on at least the set of filtered measurements.

In some embodiments, the step of determining the position of the target may comprise: determining the position of the target by using a positioning scheme applicable to a single one of the first number of terminal devices while the set of original measurement, which is associated with the single terminal device and is input to the positioning scheme, is replaced with the set of filtered measurements. In some embodiments, the step of determining the set of filtered measurements may comprise: determining each member of the set of filtered measurements as a weighted average of a first number of original measurements, each of the first number of original measurements belonging to a set of original measurements associated with a corresponding one of the first number of terminal devices.

In some embodiments, when all of original measurements associated with a second number of terminal devices from the first number of terminal devices are LOS measurements, the original measurements associated with all of the second number of all-LOS-path terminal devices may be selected to determine the set of filtered measurements, and a weight associated with an original measurement may be determined as follows: a ratio of an RSRP corresponding to the original measurement to a sum of all RSRPs corresponding to the selected original measurements used for determining a corresponding filtered measurement, when the original measurement is selected; and/or 0, when the original measurement is not selected.

In some embodiments, when at least one original measurement for each of the first number of terminal devices is an NLOS measurement, a weight associated with an original measurement may be determined as a ratio of 1 to the first number. In some embodiments, when at least one original measurement for each of the first number of terminal devices is an NLOS measurement, a weight associated with an original measurement is determined as a ratio of an RSRP corresponding to the original measurement to a sum of all RSRPs corresponding to the first number of original measurements used for determining a corresponding filtered measurement.

In some embodiments, at least three members in each set from the first number of sets of original measurements may be ToA measurements, from which at least three members in the set of filtered measurements, which are filtered ToA measurements, are determined. In some embodiments, each of at least three ToAs associated with a terminal device may be measured on a reference signal transmitted between the terminal device and a corresponding one of at least three access points, wherein the at least three access points may comprise at least a reference access point, a first access point, and a second access point.

In some embodiments, a first filtered RSTD for the reference access point and the first access point and a second filtered RSTD for the reference access point and the second access point may be calculated as follows: the first filtered RSTD may be calculated as a difference between a filtered ToA associated with the first access point and a filtered ToA associated with the reference access point; and/or the second filtered RSTD may be calculated as a difference between a filtered ToA associated with the second access point and a filtered ToA associated with the reference access point. In some embodiments, the positioning scheme may comprise at least a ranging measurement based positioning scheme.

In some embodiments, the positioning scheme may comprise at least one of: DL-TDoA; UL-TDoA; and Multi-RTT. In some embodiments, an access point may be a digital headend when a digital indoor system is used to do indoor positioning. In some embodiments, the terminal device may be a UE. In some embodiments, each of the first number of terminal devices may be a UE. In some embodiments, before the step of determining the set of filtered measurement, the method 900 may further comprise: receiving, from a network node, association information that indicates at least one of: that the target is associated with the first number of terminal devices; and that the filtered measurement is to be determined based on the first number of sets of measurements associated with the first number of terminal devices. In some embodiments, the association information may be received from an LCS server via a GMLC, an AMF, and an access point. In some embodiments, the associated information may be transmitted by the LCS server to the LMF.

In some embodiments, before the step of determining the set of filtered measurements, the method 900 may further comprise: determining whether all of the first number of terminal devices are co-located with the target or not. In some embodiments, the step of determining whether all of the first number of terminal devices are co-located with the target or not may comprise: determining whether the first number of terminal devices are associated with a same serving cell ID; and determining whether RSRPs measured by the first number of terminal devices over one or more same RS resources have relative differences from each other less than a threshold.

In some embodiments, reference signals that are measured may comprise at least one of: a PRS; and an SRS. In some embodiments, the RAT may comprise one of: NR; LTE; Wi-Fi; and Bluetooth. In some embodiments, the set of original measurements associated with each of the rest of the first number of terminal devices other than the terminal device may be sent to the terminal device via an inter-terminal device wireless connection. In some embodiments, the inter-terminal device wireless connection may comprise at least one of: NR sidelink; LTE sidelink; Wi-Fi; and Bluetooth.

Fig. 10 schematically shows an embodiment of an arrangement which may be used in a network node and/or a terminal device according to an embodiment of the present disclosure. Comprised in the arrangement 1000 are a processing unit 1006, e.g., with a Digital Signal Processor (DSP) or a Central Processing Unit (CPU) . The processing unit 1006 may be a single unit or a plurality of units to perform different actions of procedures described herein. The arrangement 1000 may also comprise an input unit 1002 for receiving signals from other entities, and an output unit 1004 for providing signal (s) to other entities. The input unit 1002 and the output unit 1004 may be arranged as an integrated entity or as separate entities.

Furthermore, the arrangement 1000 may comprise at least one computer program product 1008 in the form of a non-volatile or volatile memory, e.g., an Electrically Erasable Programmable Read-Only Memory (EEPROM) , a flash memory and/or a hard drive. The computer program product 1008 comprises a computer program 1010, which comprises code/computer readable instructions, which when executed by the processing unit 1006 in the arrangement 1000 causes the arrangement 1000 and/or the network node and/or the terminal device in which it is comprised to perform the actions, e.g., of the procedure described earlier in conjunction with Fig. 3, Fig. 4, Fig. 7 to Fig. 9 or any other variant.

The computer program 1010 may be configured as a computer program code structured in

computer program modules

1010A and 1010B. Hence, in an exemplifying embodiment when the arrangement 1000 is used in a network node for positioning a target that carries a first number of terminal devices and when the first number is greater than 1, the code in the computer program of the arrangement 1000 includes: a module 1010A configured to determine a set of filtered measurements based on at least a first number of sets of original measurements that are measured by a same RAT, each of the first number of sets being associated with a corresponding one of the first number of terminal devices; and a module 1010B configured to determine a position of the target based on at least the set of filtered measurements.

The computer program 1010 may be configured as a computer program code structured in computer program modules 1010C and 1010D. Hence, in an exemplifying embodiment when the arrangement 1000 is used in a terminal device for positioning a target that carries a first number of terminal devices comprising the terminal device and when the first number is greater than 1, the code in the computer program of the arrangement 1000 includes: a module 1010C configured to determine a set of filtered measurements based on at least a first number of sets of original measurements that are measured by a same RAT, each of the first number of sets being associated with a corresponding one of the first number of terminal devices; and a module 1010D configured to determine a position of the target based on at least the set of filtered measurements.

The computer program modules could essentially perform the actions of the flow illustrated in Fig. 3, Fig. 4, Fig. 7 to Fig. 9, to emulate the terminal device and/or the network node. In other words, when the different computer program modules are executed in the processing unit 1006, they may correspond to different modules in the network node and/or the terminal device.

Although the code means in the embodiments disclosed above in conjunction with Fig. 10 are implemented as computer program modules which when executed in the processing unit causes the arrangement to perform the actions described above in conjunction with the figures mentioned above, at least one of the code means may in alternative embodiments be implemented at least partly as hardware circuits.

The processor may be a single CPU (Central processing unit) , but could also comprise two or more processing units. For example, the processor may include general purpose microprocessors; instruction set processors and/or related chips sets and/or special purpose microprocessors such as Application Specific Integrated Circuit (ASICs) . The processor may also comprise board memory for caching purposes. The computer program may be carried by a computer program product connected to the processor. The computer program product may comprise a computer readable medium on which the computer program is stored. For example, the computer program product may be a flash memory, a Random-access memory (RAM) , a Read-Only Memory (ROM) , or an EEPROM, and the computer program modules described above could in alternative embodiments be distributed on different computer program products in the form of memories within the network node and/or terminal device.

Correspondingly to the method 800 as described above, an exemplary network node for positioning a target that carries a first number of terminal devices is provided. In some embodiments, the first number may be greater than 1. Fig. 11 is a block diagram of an exemplary network node 1100 according to an embodiment of the present disclosure. The network node 1100 may be, e.g., the LMF 720 or the BS 105-1 in some embodiments.

The network node 1100 may be configured to perform the method 800 as described above in connection with Fig. 8. As shown in Fig. 11, the network node 1100 may comprise: a first determining module 1110 configured to determine a set of filtered measurements based on at least a first number of sets of original measurements that are measured by a same RAT, each of the first number of sets being associated with a corresponding one of the first number of terminal devices; and a second determining module 1120 configured to determine a position of the target based on at least the set of filtered measurements.

The above modules 1110 and/or 1120 may be implemented as a pure hardware solution or as a combination of software and hardware, e.g., by one or more of: a processor or a micro-processor and adequate software and memory for storing of the software, a Programmable Logic Device (PLD) or other electronic component (s) or processing circuitry configured to perform the actions described above, and illustrated, e.g., in Fig. 8. Further, the network node 1100 may comprise one or more further modules, each of which may perform any of the steps of the method 800 described with reference to Fig. 8.

Correspondingly to the method 900 as described above, an exemplary terminal device for positioning a target that carries a first number of terminal devices comprising the terminal device is provided. In some embodiments, the first number may be greater than 1. Fig. 12 is a block diagram of an exemplary terminal device 1200 according to an embodiment of the present disclosure. The terminal device 1200 may be, e.g., the UE a 100-1 or the UE b 100-2 in some embodiments.

The terminal device 1200 may be configured to perform the method 900 as described above in connection with Fig. 9. As shown in Fig. 12, the terminal device 1200 may comprise: a first determining module 1210 configured to determine a set of filtered measurements based on at least a first number of sets of original measurements that are measured by a same RAT, each of the first number of sets being associated with a corresponding one of the first number of terminal devices; and a second determining module 1220 configured to determine a position of the target based on at least the set of filtered measurements.

The above modules 1210 and/or 1220 may be implemented as a pure hardware solution or as a combination of software and hardware, e.g., by one or more of: a processor or a micro-processor and adequate software and memory for storing of the software, a PLD or other electronic component (s) or processing circuitry configured to perform the actions described above, and illustrated, e.g., in Fig. 9. Further, the terminal device 1200 may comprise one or more further modules, each of which may perform any of the steps of the method 900 described with reference to Fig. 9.

The present disclosure is described above with reference to the embodiments thereof. However, those embodiments are provided just for illustrative purpose, rather than limiting the present disclosure. The scope of the disclosure is defined by the attached claims as well as equivalents thereof. Those skilled in the art can make various alternations and modifications without departing from the scope of the disclosure, which all fall into the scope of the disclosure.

The following references are mentioned in the present disclosure and they are incorporated herein by reference in their entireties.

Reference List

[1] Study on Indoor Positioning Enhancements, 3GPP TR 37.857 V13.1.0, Dec. 2015.

[2] Z. Chaloupka, "Technology and standardization gaps for high accuracy positioning in 5G, " IEEE Communications Standards Magazine, vol. 1, no. 1, pp. 59-65, Mar. 2017.

[3] W.H. Foy, "Position-location solutions by Taylor-series estimation, " IEEE Trans. on Aerospace and Electronic Systems, vol. AES-12, no. 2, pp. 187-194, Mar. 1976.

[4] J.O. Smith and J.S. Abel, "Closed-form least-squares source location estimation from range-difference measurements, " IEEE Trans. on Acoust., Speech, Signal Process., vol. ASSP-35, no. 12, pp. 1661-1669, Dec. 1987.

[5] Y.T. Chan and K.C. Ho, "A simple and efficient estimator for hyperbolic location, " IEEE Trans. on Signal Processing, vol. 42, no. 8, pp. 1905-1915, Aug. 1994.

[6] H. Kong, Y. Kwon, and T. Sung, "Comparisons of TDOA triangulation solutions for indoor positioning, " in Proc. Int. Symp. GNSS, Sydney, Australia, pp. 1-11, Dec. 2004.

[7] Y. Qi, C.B. Soh, E. Gunawan, K. -S. Low, and A. Maskooki, "An accurate 3D UWB hyperbolic localization in indoor multipath environment using iterative Taylor-series estimation, " in Proc. IEEE Veh. Technol. Conf., pp. 1-5, Jun. 2013.

[8] X. Li and S. Yang, "The indoor real-time 3D localization algorithm using UWB, " in Proc. Int. Conf. Adv. Mechatron. Syst., pp. 337-342, Aug. 2015.

[9] K. Lee, W. Hwang, H. Ryu, and H. -J. Choi, "New TDOA-based three-dimensional positioning method for 3GPP LTE system, " ETRI Journal, vol. 39, no. 2, pp. 264-274, Apr. 2017.

[10] C. -Y. Chen and W. -R. Wu, "Three-dimensional positioning for LTE systems, " IEEE Trans. on Vehicular Technology, vol. 66, no. 4, pp. 3220-3234, Apr. 2017.

[11] Positioning with L TE, Ericsson White Paper, 2011 Sept.

Claims

A method (800) at a network node (105-1, 720) for positioning a target (101) that carries a first number of terminal devices (100) , the first number being greater than 1, the method (800) comprising:

determining (S810) a set of filtered measurements based on at least a first number of sets of original measurements that are measured by a same Radio Access Technology (RAT) , each of the first number of sets being associated with a corresponding one of the first number of terminal devices (100) ; and

determining (S820) a position of the target (101) based on at least the set of filtered measurements.
The method (800) of claim 1, wherein the step of determining (S820) the position of the target (101) comprises:

determining the position of the target (101) by using a positioning scheme applicable to a single one (100-1) of the first number of terminal devices (100) while the set of original measurements, which is associated with the single terminal device (100-1) and is input to the positioning scheme, is replaced with the set of filtered measurements.
The method (800) of claim 1 or 2, wherein the step of determining (S810) the set of filtered measurements comprises:

determining each member of the set of filtered measurements as a weighted average of a first number of original measurements, each of the first number of original measurements belonging to a set of original measurements associated with a corresponding one of the first number of terminal devices (100) .
The method (800) of any of claims 1 to 3, wherein when all of original measurements associated with a second number of terminal devices from the first number of terminal devices (100) are Line Of Sight (LOS) measurements, the original measurements associated with only one of the second number of all-LOS-path terminal device are selected to determine the set of filtered measurements, and a weight associated with an original measurement is determined as follows:

- 1, when the original measurement is selected; and/or

- 0, when the original measurement is not selected.
The method (800) of any of claims 1 to 4, wherein when all of original measurements associated with a second number of terminal devices from the first number of terminal devices (100) are LOS measurements, the original measurements associated with all of the second number of all-LOS-path terminal devices are selected to determine the set of filtered measurements, and a weight associated with an original measurement is determined as follows:

- a ratio of 1 to the second number, when the original measurement is selected; and/or

- 0, when the original measurement is not selected.
The method (800) of any of claims 1 to 5, wherein when all of original measurements associated with a second number of terminal devices from the first number of terminal devices (100) are LOS measurements, the original measurements associated with all of the second number of ali-LOS-path terminal devices are selected to determine the set of filtered measurements, and a weight associated with an original measurement is determined as follows:

- a ratio of a Reference Signal Received Power (RSRP) corresponding to the original measurement to a sum of all RSRPs corresponding to the selected original measurements used for determining a corresponding filtered measurement, when the original measurement is selected; and/or

- 0, when the original measurement is not selected.
The method (800) of any of claims 1 to 6, wherein when at least one original measurement for each of the first number of terminal devices (100) is a Non-LOS (NLOS) measurement, a weight associated with an original measurement is determined as a ratio of 1 to the first number.
The method (800) of any of claims 1 to 7, wherein when at least one original measurement for each of the first number of terminal devices (100) is an NLOS measurement, a weight associated with an original measurement is determined as a ratio of an RSRP corresponding to the original measurement to a sum of all RSRPs corresponding to the first number of original measurements used for determining a corresponding filtered measurement.
The method (800) of any of claims 1 to 8, wherein when at least one original measurement for each of the first number of terminal devices (100) is an NLOS measurement, and when there are one or more LOS measurements among the original measurements used for determining a corresponding filtered measurement, a weight associated with an original measurement used for determining the corresponding filtered measurement is determined as follows:

- 1, when the original measurement is the only one LOS measurement among the original measurements used for determining the corresponding filtered measurement, or when the original measurement is one of multiple LOS measurements among the original measurements used for determining the corresponding filtered measurement and has an RSRP greater than RSRPs corresponding to other original measurements that are LOS measurements and used for determining the corresponding filtered measurement; and/or

- 0, otherwise.
The method (800) of any of claims 1 to 9, wherein when at least one original measurement for each of the first number of terminal devices (100) is an NLOS measurement, and when there is no LOS measurement among the original measurements used for determining a corresponding filtered measurement, a weight associated with an original measurement used for determining the corresponding filtered measurement is determined as a ratio of 1 to the first number.
The method (800) of any of claims 1 to 9, wherein when at least one original measurement for each of the first number of terminal devices (100) is an NLOS measurement, and when there is no LOS measurement among the original measurements used for determining a corresponding filtered measurement, a weight associated with an original measurement used for determining the corresponding filtered measurement is determined as a ratio of an RSRP corresponding to the original measurement to a sum of all RSRPs corresponding to the first number of original measurements used for determining the corresponding filtered measurement.
The method (800) of any of claims 9 to 11, wherein the first number of terminal devices (100) are separated from each other by a distance less than a first threshold.
The method (800) of any of claims 1 to 12, wherein at least three members in each set from the first number of sets of original measurements are Time of Arrival

(ToA) measurements, from which at least three members in the set of filtered measurements, which are filtered ToA measurements, are determined.
The method (800) of claim 13, wherein each of at least three ToAs associated with a terminal device is measured on a reference signal transmitted between the terminal device and a corresponding one of at least three access points (105) ,

wherein the at least three access points (105) comprise at least a reference access point (105-1) , a first access point (105-2) , and a second access point (105-3) .
The method (800) of claim 13 or 14, wherein a first filtered Reference Signal Time Difference (RSTD) for the reference access point (105-1) and the first access point (105-2) and a second filtered RSTD for the reference access point (105-1) and the second access point (105-3) are calculated as follows:

- the first filtered RSTD is calculated as a difference between a filtered ToA associated with the first access point (105-2) and a filtered ToA associated with the reference access point (105-1) ; and/or

- the second filtered RSTD is calculated as a difference between a filtered ToA associated with the second access point (105-3) and a filtered ToA associated with the reference access point (105-1) .
The method (800) of any of claims 1 to 15, wherein the positioning scheme comprises at least a ranging measurement based positioning scheme.
The method (800) of any of claims 1 to 16, wherein the positioning scheme comprises at least one of:

- Downlink Time Difference of Arrival (DL-TDoA) ;

- Uplink Time Difference of Arrival (UL-TDoA) ; and

- Multi-cell Round Trip Time (Multi-RTT) .
The method (800) of any of claims 1 to 17, wherein an access point (105-1, 105-2, 105-3) is a digital headend when a digital indoor system is used to do indoor positioning.
The method (800) of any of claims 1 to 18, wherein the network node (105-1, 720) is at least one of:

- a Location Management function (LMF) (720) ; and

- an access point (105-1) .
The method (800) of any of claims 1 to 19, wherein before the step of determining (S810) the set of filtered measurements, the method (800) further comprises:

receiving, from another network node (740) , association information that indicates at least one of:

- that the target (101) is associated with the first number of terminal devices (100) ; and

- that the set of filtered measurements is to be determined based on the first number of sets of original measurements associated with the first number of terminal devices (100) .
The method (800) of claim 20, wherein when the network node (105-1, 720) is an LMF (720) , the association information is received from a Location Service (LCS) server (740) via a Gateway Mobile Location Center (GMLC) (730) and an Access and Mobility Management Function (AMF) (710) .
The method (800) of claim 20 or 21, wherein when the network node (105-1, 720) is an access point (105-1) , the association information is received from an LCS server (740) via a GMLC (730) and an AMF (710) .
The method (800) of claim 22, wherein the associated information is transmitted by the LCS server (740) to the LMF (720) .
The method (800) of any of claims 1 to 23, wherein before the step of determining (S810) the set of filtered measurements, the method (800) further comprises:

determining whether all of the first number of terminal devices (100) are co-located with the target (101) or not.
The method (800) of claim 24, wherein the step of determining whether all of the first number of terminal devices (100) are co-located with the target (101) or not comprises:

- determining whether the first number of terminal devices (100) are associated with a same serving cell ID; and

- determining whether RSRPs measured by the first number of terminal devices (100) over one or more same reference signal (RS) resources have relative differences from each other less than a threshold.
The method (800) of any of claims 1 to 25, wherein when compared with using one terminal device for positioning a target (101) , the utilization of the first number of terminal devices (100) and the corresponding filtered measurements improves the positioning scheme in terms of at least one of positioning accuracy and positioning integrity.
The method (800) of any of claims 1 to 26, wherein reference signals that are measured comprise at least one of:

- a Positioning Reference Signal (PRS) ; and

- a Sounding Reference Signal (SRS) .
The method (800) of any of claims 1 to 27, wherein the RAT comprises one of:

- New Radio (NR) ;

- Long Term Evolution (LTE) ;

- Wi-Fi; and

- Bluetooth.
A network node (105-1, 720, 1000, 1100) , comprising:

a processor (1006) ;

a memory (1008) storing instructions which, when executed by the processor (1006) , cause the processor (1006) to carry out the method (800) of any of claims 1 to 28.
A method (900) at a terminal device (100-1) for positioning a target (101) that carries a first number of terminal devices (100) comprising the terminal device (100-1) , the first number being greater than 1, the method (900) comprising:

determining (S910) a set of filtered measurements based on at least a first number of sets of original measurements that are measured by a same Radio Access Technology (RAT) , each of the first number of sets being associated with a corresponding one of the first number of terminal devices (100) ; and

determining (S920) a position of the target (101) based on at least the set of filtered measurements.
The method (900) of claim 30, wherein the step of determining (S920) the position of the target (101) comprises:

determining the position of the target (101) by using a positioning scheme applicable to a single one of the first number of terminal devices (100) while the set of original measurement, which is associated with the single terminal device and is input to the positioning scheme, is replaced with the set of filtered measurements.
The method (900) of claim 30 or 31, wherein the step of determining (S910) the set of filtered measurements comprises:

determining each member of the set of filtered measurements as a weighted average of a first number of original measurements, each of the first number of original measurements belonging to a set of original measurements associated with a corresponding one of the first number of terminal devices (100) .
The method (900) of any of claims 30 to 32, wherein when all of original measurements associated with a second number of terminal devices from the first number of terminal devices (100) are Line Of Sight (LOS) measurements, the original measurements associated with only one of the second number of all-LOS-path terminal device are selected to determine the set of filtered measurements, and a weight associated with an original measurement is determined as follows:

- 1, when the original measurement is selected; and/or

- 0, when the original measurement is not selected.
The method (900) of any of claims 30 to 33, wherein when all of original measurements associated with a second number of terminal devices from the first number of terminal devices (100) are LOS measurements, the original measurements associated with all of the second number of all-LOS-path terminal devices are selected to determine the set of filtered measurements, and a weight associated with an original measurement is determined as follows:

- a ratio of 1 to the second number, when the original measurement is selected; and/or

- 0, when the original measurement is not selected.
The method (900) of any of claims 30 to 34, wherein when all of original measurements associated with a second number of terminal devices from the first number of terminal devices (100) are LOS measurements, the original measurements associated with all of the second number of all-LOS-path terminal devices are selected to determine the set of filtered measurements, and a weight associated with an original measurement is determined as follows:

- a ratio of a Reference Signal Received Power (RSRP) corresponding to the original measurement to a sum of all RSRPs corresponding to the selected original measurements used for determining a corresponding filtered measurement, when the original measurement is selected; and/or

- 0, when the original measurement is not selected.
The method (900) of any of claims 30 to 35, wherein when at least one original measurement for each of the first number of terminal devices (100) is a Non-LOS (NLOS) measurement, a weight associated with an original measurement is determined as a ratio of 1 to the first number.
The method (900) of any of claims 30 to 36, wherein when at least one original measurement for each of the first number of terminal devices (100) is an NLOS measurement, a weight associated with an original measurement is determined as a ratio of an RSRP corresponding to the original measurement to a sum of all RSRPs corresponding to the first number of original measurements used for determining a corresponding filtered measurement.
The method (900) of any of claims 30 to 37, wherein when at least one original measurement for each of the first number of terminal devices (100) is an NLOS measurement, and when there are one or more LOS measurements among the original measurements used for determining a corresponding filtered measurement, a weight associated with an original measurement used for determining the corresponding filtered measurement is determined as follows:

- 1, when the original measurement is the only one LOS measurement among the original measurements used for determining the corresponding filtered measurement, or when the original measurement is one of multiple LOS measurements among the original measurements used for determining the corresponding filtered measurement and has an RSRP greater than RSRPs corresponding to other original measurements that are LOS measurements and used for determining the corresponding filtered measurement; and/or

- 0, otherwise.
The method (900) of any of claims 30 to 38, wherein when at least one original measurement for each of the first number of terminal devices (100) is an NLOS measurement, and when there is no LOS measurement among the original measurements used for determining a corresponding filtered measurement, a weight associated with an original measurement used for determining the corresponding filtered measurement is determined as a ratio of 1 to the first number.
The method (900) of any of claims 30 to 38, wherein when at least one original measurement for each of the first number of terminal devices (100) is an NLOS measurement, and when there is no LOS measurement among the original measurements used for determining a corresponding filtered measurement, a weight associated with an original measurement used for determining the corresponding filtered measurement is determined as a ratio of an RSRP corresponding to the original measurement to a sum of all RSRPs corresponding to the first number of original measurements used for determining the corresponding filtered measurement.
The method (900) of any of claims 38 to 40, wherein the first number of terminal devices (100) are separated from each other by a distance less than a first threshold.
The method (900) of any of claims 30 to 41, wherein at least three members in each set from the first number of sets of original measurements are Time of Arrival (ToA) measurements, from which at least three members in the set of filtered measurements, which are filtered ToA measurements, are determined.
The method (900) of claim 42, wherein each of at least three ToAs associated with a terminal device is measured on a reference signal transmitted between the terminal device and a corresponding one of at least three access points (105) ,

wherein the at least three access points (105) comprise at least a reference access point (105-1) , a first access point (105-2) , and a second access point (105-3) .
The method (900) of claim 42 or 43, wherein a first filtered Reference Signal Time Difference (RSTD) for the reference access point (105-1) and the first access point (105-2) and a second filtered RSTD for the reference access point (105-1) and the second access point (105-3) are calculated as follows:

- the first filtered RSTD is calculated as a difference between a filtered ToA associated with the first access point (105-2) and a filtered ToA associated with the reference access point (105-1) ; and/or

- the second filtered RSTD is calculated as a difference between a filtered ToA associated with the second access point (105-3) and a filtered ToA associated with the reference access point (105-1) .
The method (900) of any of claims 30 to 44, wherein the positioning scheme comprises at least a ranging measurement based positioning scheme.
The method (900) of any of claims 30 to 45, wherein the positioning scheme comprises at least one of:

- Downlink Time Difference of Arrival (DL-TDoA) ;

- Uplink Time Difference of Arrival (UL-TDoA) ; and

- Multi-cell Round Trip Time (Multi-RTT) .
The method (900) of any of claims 30 to 46, wherein an access point (105-1, 105-2, 105-3) is a digital headend when a digital indoor system is used to do indoor positioning.
The method (900) of any of claims 30 to 47, wherein the terminal device (100-1) is a User Equipment (UE) .
The method (900) of any of claims 30 to 48, wherein each of the first number of terminal devices (100) is a UE.
The method (900) of any of claims 30 to 49, wherein before the step of determining (S910) the set of filtered measurement, the method (900) further comprises:

receiving, from a network node (740) , association information that indicates at least one of:

- that the target (101) is associated with the first number of terminal devices (100) ; and

- that the filtered measurement is to be determined based on the first number of sets of measurements associated with the first number of terminal devices (100) .
The method (900) of claim 50, wherein the association information is received from a Location Service (LCS) server (740) via a Gateway Mobile Location Center (GMLC) (730) , an Access and Mobility Management Function (AMF) (710) , and an access point (105-1) .
The method (900) of claim 51, wherein the associated information is transmitted by the LCS server (740) to the LMF (720) .
The method (900) of any of claims 30 to 52 wherein before the step of determining (S910) the set of filtered measurements, the method (900) further comprises:

determining whether all of the first number of terminal devices (100) are co-located with the target (101) or not.
The method (900) of claim 53, wherein the step of determining whether all of the first number of terminal devices (100) are co-located with the target (101) or not comprises:

- determining whether the first number of terminal devices (100) are associated with a same serving cell ID; and

- determining whether RSRPs measured by the first number of terminal devices (100) over one or more same reference signal (RS) resources have relative differences from each other less than a threshold.
The method (900) of any of claims 30 to 54, wherein when compared with using one terminal device for positioning a target (101) , the utilization of the first number of terminal devices (100) and the corresponding filtered measurements improves the positioning scheme in terms of at least one of positioning accuracy and positioning integrity.
The method (900) of any of claims 30 to 55, wherein reference signals that are measured comprise at least one of:

- a Positioning Reference Signal (PRS) ; and

- a Sounding Reference Signal (SRS) .
The method (900) of any of claims 30 to 56, wherein the RAT comprises one of:

- New Radio (NR) ;

- Long Term Evolution (LTE) ;

- Wi-Fi; and

- Bluetooth.
The method (900) of any of claims 30 to 57, wherein the set of original measurements associated with each (100-2) of the rest of the first number of terminal devices (100) other than the terminal device (100-1) is sent to the terminal device (100-1) via an inter-terminal device wireless connection.
The method (900) of claim 58, wherein the inter-terminal device wireless connection comprises at least one of:

- New Radio (NR) sidelink;

- Long Term Evolution (LTE) sidelink;

- Wi-Fi; and

- Bluetooth.
A terminal device (100-1, 1000, 1200) , comprising:

a processor (1006) ;

a memory (1008) storing instructions which, when executed by the processor (1006) , cause the processor (1006) to carry out the method (900) of any of claims 30 to 59.
A computer program (1010) comprising instructions which, when executed by at least one processor (1006) , cause the at least one processor (1006) to carry out the method (800, 900) of any of claims 1 to 28 and 30 to 59.
A carrier (1008) containing the computer program (1010) of claim 61, wherein the carrier (1008) is one of an electronic signal, optical signal, radio signal, or computer readable storage medium.
A method at a telecommunication system (30, 70) for positioning a target (101) that carries a first number of terminal devices (100) , the first number being greater than 1, the method (900) comprising:

determining (S810, S910) , at a network node (105-1, 720) and/or a terminal device (100-1) , a set of filtered measurements based on at least a first number of sets of original measurements that are measured by a same Radio Access Technology (RAT) , each of the first number of sets being associated with a corresponding one of the first number of terminal devices (100) ; and

determining (S820, S920) , at the network node (105-1, 720) and/or the terminal device (100-1) , a position of the target (101) based on at least the set of filtered measurements.
The method of claim 63, wherein the terminal device is one of the first number of terminal devices (100) .
The method of claim 63 or 64, wherein when the set of filtered measurements is determined at the terminal device (100-1) , the set of original measurements associated with each (100-2) of the rest of the first number of terminal devices (100) is sent to the terminal device (100-1) via an inter-terminal device wireless connection.
The method of claim 65, wherein the inter-terminal device wireless connection comprises at least one of:

- New Radio (NR) sidelink;

- Long Term Evolution (LTE) sidelink;

- Wi-Fi; and

- Bluetooth.
The method of any of claims 63 to 66, wherein the network node (105-1, 720) is a network node (105-1, 720) of claim 29.
The method of any of claims 63 to 67, wherein the terminal device (100-1) is a terminal device (100-1) of claim 60.
A telecommunication system (30, 70) for positioning a target (101) that carries a first number of terminal devices (100) , the first number being greater than 1, the telecommunication system comprising a network node (105-1, 720) and/or one of the first number of terminal devices (100-1) , for

determining (S810, S910) , a set of filtered measurements based on at least a first number of sets of original measurements that are measured by a same Radio Access Technology (RAT) , each of the first number of sets being associated with a corresponding one of the first number of terminal devices (100) ; and

determining (S820, S920) a position of the target (101) based on at least the set of filtered measurements.