Receiver, transmitter and method for line-of-sight path detection

Abstract

A method performed by a receiver for Line-of-sight, LoS, path detection in a reception of a signal from a transmitter, the method comprising obtaining an antenna gain of the transmitter and determining an amplitude threshold (62) and / or a time threshold (63) to be used for the LoS path detection at least according to the obtained antenna gain. The method comprises detecting whether at least one smaller peak (6b) appears earlier than a max peak (6a) of a cross-correlated time domain series of the received signal that applies to the determined threshold(s) (62, 63). The at least one smaller peak (6b) is considered to apply to the determined threshold(s) if the at least one smaller peak (6b) is above the amplitude threshold (62) and / or after the time threshold (63). A peak from the detected peak(s) is determined as associated with the LoS path. Publ.

Description

[0001] RECEIVER, TRANSMITTER AND METHOD FOR LINE-OF-SIGHT PATH DETECTION

[0002] TECHNICAL FIELD

[0003] Embodiments herein relate to a methods performed by a receiver and a transmitter handling Line-of-sight (LoS) path detection. Embodiments herein also relate to a receiver and transmitter adapted to function according to the methods. Embodiments herein also relate to a computer program and carrier comprising a computer program.

[0004] BACKGROUND

[0005] In a typical wireless communication network, wireless devices, also known as wireless communication devices, mobile stations, stations (STA) and / or User Equipment (UE), communicate via a Wide Area Network or a Local Area Network such as a Wi-Fi network or a cellular network comprising a Radio Access Network (RAN) part and a Core Network (CN) part. The RAN covers a geographical area which is divided into service areas or cell areas, which may also be referred to as a beam or a beam group, with each service area or cell area being served by a radio network node such as a radio access node e.g., a Wi-Fi access point, a Base Station (BS) or a radio base station (RBS), which in some networks may also be denoted, for example, a Base Station (BS), a NodeB, eNodeB (eNB), or gNodeB (gNB) as denoted in Fifth Generation (5G) telecommunications. A service area or cell area is a geographical area where radio coverage is provided by the radio network node. The radio network node communicates over an air interface operating on a radio frequency with the wireless devices within the range of the radio network node.

[0006] 3rd Generation Partnership Project (3GPP) is the standardization body for specifying the standards for the cellular system evolution, e.g., including 3G, 4G, 5G and the future evolutions. Specifications for Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Packet System (EPS) have been completed within the 3GPP. In 4G also called a Fourth Generation (4G) network, EPS is core network and E-UTRA is radio access network. In 5G, 5G Core (5GC) is core network, NR is radio access network. As a continued network evolution, the new release of 3GPP specifies a 5G network also referred to as 5G New Radio (NR) and 5GC.

[0007] Frequency bands for 5G NR are being separated into two different frequency ranges, Frequency Range 1 (FR1) and Frequency Range 2 (FR2). FR1 comprises sub-6 GHz frequency bands. Some of these bands are bands traditionally used by legacy standards but have been extended to cover potential new spectrum offerings from 410 MHz to 7125 MHz. FR2 comprises frequency bands from 24.25 GHz to 52.6 GHz. Bands in this millimeter wave range have shorter range but higher available bandwidth than bands in the FR1.

[0008] Multi-antenna techniques may significantly increase the data rates and reliability of a wireless communication system. For a wireless connection between a single user, such as UE, and a base station (BS), the performance is in particular improved if both the transmitter and the receiver are equipped with multiple antennas, which results in a Multiple-Input Multiple-Output (MIMO) communication channel. This may be referred to as Single-User (SU)-MIMO. In the scenario where MIMO techniques is used for the wireless connection between multiple users and the base station, MIMO enables the users to communicate with the base station simultaneously using the same time-frequency resources by spatially separating the users, which increases further the cell capacity. This may be referred to as Multi-User (MU)-MIMO. Note that MU-MIMO may benefit when each UE only has one antenna. The cell capacity can be increased linearly with respect to the number of antennas at the BS side. Due to that, more and more antennas are employed in BS. Such systems and / or related techniques are commonly referred to as massive MIMO.

[0009] Different positioning methods or technologies are known, and some of the most used technologies pertinent to embodiments herein will now be described.

[0010] Positioning in NR is supported by the architecture shown in Figure 1, illustrating the NG-RAN LOS Protocols. The Location Management Function (LMF) 11 is the location node in NR. There are also interactions between the location node and the gNodeB via the NR positioning protocol A (NRPPa). The interactions between the gNodeB and the device UE 12 is supported via the Radio Resource Control (RRC) protocol.

[0011] It should be noted that the gNB 13 and ng-eNB 14 may not always both be present, and that when both the gNB 13 and ng-eNB 14 are present, the NG-C interface is only present for one of them.

[0012] NR currently supports below RAT Dependent positioning methods:

[0013] DL-TDOA:

[0014] The downlink (DL) time difference of arrival (TDOA) positioning method makes use of the DL reference signal time difference (RSTD), and optionally DL positioning reference signal (PRS) reference signal received power (RSRP) of downlink signals received from multiple TPs, at the UE. The UE measures the DL RSTD, and optionally DL PRS RSRP, of the received signals using assistance data received from the positioning server, and the resulting measurements are used along with other configuration information to locate the UE in relation to the neighboring TPs.

[0015] Multi-RTT:

[0016] The Multi round trip time (Multi-RTT) positioning method makes use of the UE Rx-Tx measurements and DL PRS RSRP of downlink signals received from multiple TRPs, measured by the UE and the measured gNB Rx-Tx measurements and UL SRS-RSRP at multiple TRPs of uplink signals transmitted from UE.

[0017] UL-TDOA:

[0018] The UL TDOA positioning method makes use of the UL TDOA, and optionally UL SRS-RSRP, at multiple RPs of uplink signals transmitted from UE. The RPs measure the UL TDOA, and optionally UL SRS-RSRP, of the received signals using assistance data received from the positioning server, and the resulting measurements are used along with other configuration information to estimate the location of the UE.

[0019] DL-AoD:

[0020] The DL angle of departure (AoD) positioning method makes use of the measured DL PRS RSRP of downlink signals received from multiple TPs, at the UE. The UE measures the DL PRS RSRP of the received signals using assistance data received from the positioning server, and the resulting measurements are used along with other configuration information to locate the UE in relation to the neighboring TPs.

[0021] UL-AoA:

[0022] The UL angle of arrival (AoA) positioning method makes use of the measured azimuth (A) and zenith (Z) angle of arrival at multiple RPs of uplink signals transmitted from the UE. The RPs measure A-AoA and Z-AoA of the received signals using assistance data received from the positioning server, and the resulting measurements are used along with other configuration information to estimate the location of the UE.

[0023] NR-ECID:

[0024] NR Enhanced Cell ID (NR E-CID) positioning refers to techniques which use additional UE measurements and / or NR radio resource and other measurements to improve the UE location estimate.

[0025] The positioning modes can be categorized in below three areas:

[0026] - UE-Assisted’. The UE performs measurements with or without assistance from the network and sends these measurements to the enhanced serving mobile location server (E-SMLC) where the position calculation may take place. - UE-Based. The UE performs measurements and calculates its own position with assistance from the network.

[0027] - Standalone’. The UE performs measurements and calculates its own position without network assistance.

[0028] Line-of-siqht detection

[0029] Positioning methods using time-of-arrival (ToA), time-difference-of-arrival (TDoA), or angle-of-arrival (AoA) technology are totally dependent of identifying the line-of-sight direct path at the receiver. LoS path is identified and through multi-lateration across several network receivers or UE providing assistance, the UE position can be calculated. For downlink arrival (TDoA, AoA) methods, the UE performs the LoS path detection. For uplink arrival methods, the base station performs the LoS path detection.

[0030] LoS detection reliability remains a major challenge for NR in achieving accuracy. Complex industrial environments conspire to create multipath channels where the LoS path is difficult to identify and measure. On top of the environment, distinctive antenna patterns on the transmitter and receiver sides further complicate the multipath channels.

[0031] LoS detection entails in determining the lag corresponding to the max peak of the cross-correlation of the received signal and a known reference signal. In clear LoS conditions, or full LoS, this lag will correspond to the LoS path. In non line of sight (NLoS) condition however, the lag corresponding to the max peak could be a strong reflection that is received after the LoS path.

[0032] SUMMARY

[0033] As part of developing embodiments herein, the inventors identified some problems that first will be described.

[0034] In realistic scenarios, the LoS detection aims at determining the lag of the max peak of the cross-correlation or channel impulse response (CIR) of the signal of interest and checking smaller earlier peaks in a specified time window for the LoS path. The impact of the transmitter antenna pattern impacts the relative amplitudes of the peaks in the CIR.

[0035] The thresholds applied for “smaller” and “earlier” peaks are usually fixed and a compromise between missed detections and false detection. Figure 2 shows an example of an CIR with a NLoS peak 2a and a LOS peak 2b, and the thresholds as they may be applied in an LoS algorithm. The figure illustrates three different thresholds:

[0036] the noise floor threshold 21 - this is set above the noise floor. If the amplitude of the path is higher than the threshold, it is a candidate for the LoS path, the LoS threshold 22 below the max peak - LoS path must be above this threshold to be a LoS candidate, and

[0037] the time threshold 23 for the LoS path - this is set according to the coverage area of the positioning solution. For larger indoor environments, reflections from walls for instance arrive quite late in the CIR. If one of these reflections is identified as the max peak, the LoS peak would appear earlier than the max peak.

[0038] The simplest perhaps ideal case has been shown to be when the transmitter and receivers are omni-directional, in which case the amplitude and time threshold can be set in a heuristic manner. However, as illustrated in Figure 3, if the transmitter 31, communicating with a receiver 32, has high antenna gain and pointing towards a reflective surface 33, such as a wall, the late arriving max peak, representing a NLoS path 3a, will bias the system and the earlier LoS path 3b would be missed.

[0039] The impact of transmitter / receiver antenna radiation pattern has been extensively assessed in publication “Indoor Positioning Accuracy Investigations Using the Nova Simulator” 2. Y. Teganya, J. Nygren, D. Sugirtharaj, NCE Activity 188, Eridoc, August 2023.

[0040] An object of embodiments herein is to increase the likelihood of detecting early LoS peaks which might be missed in the current schemes.

[0041] According to an aspect of embodiments herein, the object is achieved by a method performed by a receiver for LoS path detection in a reception of a signal from a transmitter.

[0042] The proposed method comprises:

[0043] obtaining an antenna gain of the transmitter;

[0044] determining an amplitude threshold and / or a time threshold to be used for the LoS path detection at least according to the obtained antenna gain;

[0045] detecting whether at least one smaller peak appears earlier than a max peak of a cross-correlated time domain series of the received signal that applies to the determined threshold(s), wherein the at least one smaller peak applies to the determined threshold(s) comprises: the at least one smaller peak is above the amplitude threshold and / or after the time threshold; and

[0046] determining a peak from the detected peak(s) as possibly associated with the LoS path.

[0047] According to an aspect of embodiments herein it is proposed that when at least one smaller peak has been detected earlier than the max peak, then the earliest peak among the at least one smaller peak may be determined as possibly associated with the LoS path. However, when no smaller peak has been detected earlier than the max peak, then the max peak may be determined as possibly associated with the LoS path.

[0048] Embodiments propose that the antenna gain of the transmitter may be obtained by requesting the antenna gain of the transmitter from the transmitter, or by obtaining the antenna gain based on a type of the transmitter, from antenna gains for different types of transmitters with which the receiver is configured.

[0049] Proposed embodiments teach that determining the time threshold may comprise:

[0050] determining, based on the max peak, a CIR window of which the earlier bound / starting point is an original time threshold;

[0051] centering, when the obtained antenna gain is zero, the CIR window in relation to the max peak;

[0052] shifting, when the obtained antenna gain is above a set threshold higher than zero, the CIR window to the left in the time domain; and

[0053] reducing, when the determination dictates a reduction, a minimum amplitude threshold to look for weaker peaks.

[0054] Embodiments propose that determining the time threshold may comprise:

[0055] using a first amplitude threshold that is less than the max peak amplitude if the antenna gain is zero, and

[0056] reducing the amplitude threshold to a second amplitude threshold that is lower than the first amplitude threshold if the antenna gain is higher than zero.

[0057] Embodiments are also proposed where an original window size of the channel impulse response in the time domain may be increased based on the obtained transmitter antenna gain. It is proposed that the original CIR window size in the time domain of a first number of points may be used if the transmitter antenna gain is zero, however, it is proposed that, if the antenna gain is higher than zero, the CIR window size in the time domain may be increased to a second number of points, where the second number is higher than the first number.

[0058] According to an aspect of embodiments herein, the object is achieved by a method performed by a transmitter in communication with a receiver to enable the receiver to perform LoS path detection in the reception of a signal from the transmitter. It is proposed that the transmitter:

[0059] receives, from the receiver or another entity in charge of LoS path detection, a request for the antenna gain of the transmitter, and transmits, to the receiver or another entity in charge of LoS path detection, the antenna gain of the transmitter.

[0060] According to aspects of embodiments herein it is proposed that in an uplink application, the receiver may be a network TRP, such as a base station, and the transmitter may be a UE.

[0061] According to other aspects of embodiments herein it is proposed that in a downlink application, the receiver may be a UE and the transmitter may be a network TRP, such as a base station.

[0062] According to an aspect of embodiments herein, the object is achieved by a receiver, adapted to perform a method for LoS path detection in a reception of a signal from a transmitter, wherein the receiver is adapted to:

[0063] obtain an antenna gain of the transmitter;

[0064] determine an amplitude threshold and / or a time threshold to be used for the LoS path detection at least according to the obtained antenna gain;

[0065] detect whether at least one smaller peak appears earlier than a max peak of a cross-correlated time domain series of the received signal that applies to the determined threshold(s), wherein the at least one smaller peak applies to the determined threshold(s) comprises: the at least one smaller peak is above the amplitude threshold and / or after the time threshold; and

[0066] determine a peak from the detected peak(s) as possibly associated with the LoS path.

[0067] According to an aspect of embodiments herein it is proposed that the receiver may be adapted to determine the earliest peak among the at least one smaller peak as possibly associated with the LoS path when at least one smaller peak has been detected earlier than the max peak, or to determine the max peak as possibly associated with the LoS path when no smaller peak appears earlier than the max peak.

[0068] One proposed aspect of embodiments herein teaches that the receiver may be adapted to obtain the antenna gain of the transmitter by requesting, from the transmitter, the antenna gain of the transmitter, or by obtaining the antenna gain based on a type of the transmitter, from antenna gains for different types of transmitters with which the receiver is configured.

[0069] Aspects of embodiments herein are proposed where the receiver, in the determination of the time threshold, may be adapted to:

[0070] - determine, based on the max peak, a CIR window of which the earlier bound / starting point is an original time threshold; - center, when the obtained antenna gain is zero, the CIR window in relation to the max peak;

[0071] - shift, when the obtained antenna gain is above a set threshold higher than zero, the CIR window to the left in the time domain; and

[0072] - reduce, when the determination dictates a reduction, a minimum amplitude threshold to look for weaker peaks.

[0073] Embodiments propose that, when determining the time threshold, the receiver may be adapted to:

[0074] - use a first amplitude threshold that is less than the max peak amplitude if the transmitter antenna gain is zero; and

[0075] - reduce the amplitude threshold to a second amplitude threshold that is lower than the first set amplitude threshold if the transmitter antenna gain is higher than zero.

[0076] Aspects of embodiments herein are proposed where the receiver may be adapted to increase an original window size of the channel impulse response in the time domain based on the obtained transmitter antenna gain, and this may be done by the receiver being adapted to use the original CIR window size in the time domain of a first number of points if the transmitter antenna gain is zero, and to increase the CIR window size in the time domain to a second number of points, if the antenna gain is higher than zero, where the second number is higher than the first number.

[0077] According to an aspect of embodiments herein, the object is also achieved by a transmitter adapted to be in communication with a receiver to enable the receiver to perform LoS path detection in the reception of a signal from the transmitter, the transmitter being adapted to:

[0078] - receive, from the receiver or other entity in charge of LoS path detection, a request for the antenna gain of the transmitter, and

[0079] - transmit, to the receiver or other entity in charge of LoS path detection, the antenna gain of the transmitter.

[0080] According to an aspect of embodiments herein, it is proposed that in an uplink application, the receiver may be a network TRP, such as a base station, and the transmitter may be a UE .

[0081] According to another aspect of embodiments herein, it is proposed that in a downlink application, the receiver may be a UE and the transmitter may be a network TRP, such as a base station. According to an aspect of embodiments herein, the object is achieved by a computer program comprising instructions, which when executed by a processor, causes the processor to perform the methods herein, as performed by the receiver or the transmitter, respectively.

[0082] Embodiments also propose a carrier comprising the mentioned computer program, wherein the carrier is one of an electronic signal, an optical signal, an electromagnetic signal, a magnetic signal, an electric signal, a radio signal, a microwave signal, or a computer-readable storage medium.

[0083] Embodiments herein may provide one or more of the following advantages:

[0084] With this method of adapting the LoS thresholds depending on the UE antenna gain / pattern it is possible to achieve improved LoS detection probability and hence improved positioning accuracy for all the time-based positioning methods such as ToA, TDoA, or TA-based methods and all other hybrid positioning methods that combine temporal and angular measurements in the positioning calculations.

[0085] BRIEF DESCRIPTION OF THE DRAWINGS

[0086] Examples of embodiments herein are described in more detail with reference to attached drawings in which:

[0087] Figure 1 is a schematic block diagram illustrating the NG-RAN LOS Protocols.

[0088] Figure 2 is a graph of a Cl R showing LoS and NLoS paths.

[0089] Figure 3 is a schematic illustration of a possible positioning scenario.

[0090] Figure 4 is a graph showing a transmitter antenna pattern with non-zero antenna gain.

[0091] Figures 5a, 5b, 5c are schematic illustrations of typical TRP types.

[0092] Figure 6 is a graph showing an antenna gain / pattern impact on LoS detection thresholds.

[0093] Figures 7a, 7b, 7c are illustrations of UE radiation patterns in the horizontal and vertical planes (HP and VP respectively) on the left and corresponding UE antenna layouts on the right.

[0094] Figure 8 is a graph illustrating an example of the utility function of the antenna pattern parameter at the UE.

[0095] Figure 9 is a graph illustrating an example of a function that can be used to increase the LoS search window in the CIR.

[0096] Figure 10 is a graph illustrating a time shifted CIR window.

[0097] Figure 11 is a flowchart illustrating aspects of embodiments herein.

[0098] Figure 12 is a flowchart illustrating aspects of embodiments herein. Figure 13 is a flowchart illustrating aspects of embodiments herein.

[0099] Figure 14 is a flowchart illustrating aspects of embodiments herein.

[0100] Figure 15 is a generalized block diagram of embodiments of a receiver.

[0101] Figure 16 is a generalized block diagram of embodiments of a transmitter.

[0102] DETAILED DESCRIPTION

[0103] In embodiments herein that now will be described, proposed solutions will be described from the uplink perspective but is equally applicable in the downlink case. In the uplink case, the UE will be the transmitter and the network TRP will be the receiver. The solution is for the UE to signal its antenna characteristic in terms of antenna gain and / or pattern to the network where the LoS detection algorithms reside. Increased UE antenna gain will increase the variance of the amplitude of the LoS path as well as increase the timing advance of the LoS path. In light is these phenomena, the amplitude threshold is lowered as it may be located in a minima in the antenna pattern. Similarly, the max peak could be reflection of a distance wall and hence LoS peaks much earlier must be considered as candidates.

[0104] Antenna gain is a simple parameter describing the antenna pattern. An antenna gain of 0 dB could imply an omni-directional antenna. Figure 4 shows an example of a radiation pattern of a UE transmitter, and figures 5a, 5b and 5c shows examples of different types of antennas with typical TRP types, Figure 5a, illustrating an omni antenna without angular sensing, Figure 5b illustrating a directional antenna, integrated or external, without angular sensing, and Figure 5c illustrating an omni antenna with angular sensing.

[0105] It can be seen that if the network TRP is in the direction where the radiation is attenuated, the LoS path could be under the amplitude threshold hence it would be undetected, a missed detection, see also Figure 3. To understand the exacerbating effects of misdetection, an example is used considering a bandwidth of 100 MHz. The delay resolution between two samples in the CIR is about 10 ns under the 100MHz bandwidth, which corresponds to 3 m of range resolution. Mistaking the neighbouring sample as the correct one yields ToA error of at least 3 m which further leads to inaccurate position estimate.

[0106] In such scenarios, considering risk of inaccuracy of the position estimate, it will be very beneficial to increase the certainty of the position estimate by proposing a LoS path detection scheme based on adaptive amplitude and / or time thresholds, so that candidate LoS paths will not be missed.

[0107] The core essence of embodiments herein will be described with reference to Figure 6 illustrating that the LoS amplitude threshold 62 and / or the time threshold 63 is not fixed but varies according to the transmitter’s (e.g. UE) antenna pattern. Increasing antenna gain of the UE could potentially increase distance in time domain between the max peak 6a and the earlier LoS peak 6b depending on the UE antenna orientation with respect to the network TRP. Also, UE antenna gain could amplify the RF reflections of a distant wall. The time threshold 63 should be shifted left 64 increasing the time window for identifying candidate LoS paths.

[0108] The main embodiment of the invention is that the UE signals its transmitter antenna gain to the gNB. The gNB takes antenna gain into consideration when determining the amplitude and / or time thresholds for the LoS algorithm.

[0109] One embodiment of the invention is to increase the window size of the receiver channel impulse response if the UE has higher antenna gain. For example, if the UE transmitter antenna gain is zero, the receiver in the gNB may use a CIR of 32 points. For a UE with an antenna gain of 3 dB, the CIR window size may be increased to 64 points.

[0110] Another embodiment of the invention is to shift the CIR window in relation to the max peak. For instance, if the UE transmitter antenna gain is zero, the receiver in the gNB may use a CIR window centered in relation to the max peak. For a UE with an antenna gain of 3 dB, the CIR window size may be biased 64 to look earlier with respect to the max peak 6a. In this case, the max peak 6a will appear right shifted in the CIR window.

[0111] Another embodiment of the invention is to reduce 65 the minimum amplitude threshold with the same amount of the antenna gain. For instance, if the UE transmitter antenna gain is zero, the receiver in the gNB may use an amplitude threshold 3 dB less than max peak amplitude. For a UE with an antenna gain of 3 dB, the receiver in the gNB may use an amplitude threshold 6 dB less than max peak amplitude.

[0112] In the downlink where the UE, e.g. an automated guided vehicle (AGV), is the receiver and has some processing capabilities to accommodate the LoS extraction algorithm, it shouldn’t be understood that the gNB may report its antenna gain / pattern to the UE. Instead, the UE may use its antenna gain / pattern together with the positioning measurements to improve the LoS path detection.

[0113] The solution may be implemented without standards changes. In industrial deployments, the gNB may be configured with the antenna gain of the specific UE types used in the deployment, and the UE may be configured with the antenna gains of the gNBs serving the industrial deployment.

[0114] Antenna Gain

[0115] While 3GPP assumes UE antenna gain to be 0 dB in most studies, packaging limitations and mountings on particular devices, for instance in industry, may cause the UE antenna gain to be non-zero and / or irregular. Figures 7a, 7b and 7c shows different perspectives of an example illustrating how the UE antenna gain may vary in different directions, where left figures in Figure 7a, 7b and 7c show H and V plane patterns / curves corresponding to the different perspectives or viewing angles, where the darker blocks illustrate the antenna 72 and its locations on the UE 71. The simplest parameter for the antenna gain is the max peak value compared with the average across 360 degrees. A more sophisticated way of describing the antenna gain is with a table showing the gain at various angles on a plane, e.g. horizontal plane. Another way would be to describe the max gain and main lobe angle of the antenna.

[0116] Proposed embodiments support various levels of antenna gain parameters as input to determining the LoS amplitude and time thresholds in the radio positioning algorithm. Some examples on how to adjust the LoS threshold will now be described.

[0117] For the LoS amplitude, let yLoSbe the threshold produced by the legacy algorithms such as the one described earlier based on the noise floor and max peak and Guebe the UE antenna gain. The adjusted threshold yLoS,adj may be set as

[0118] YLos.adj ~ YLOS ~ ^(^ue)> Equation 1 Where t / (Gue) is a utility function, in same units as yLoS, of the UE antenna parameter defined as shown in Figure 8. The idea of having this shape of utility function is to avoid selecting noise as the LoS peak for higher values of Gue.

[0119] To increase the LoS search window in the CIR until the proposed start time index Tprop, see Figure 10, the UE antenna gain may be leveraged in a suitably chosen function like the one in Figure 9. Similar to the lowering of the threshold for the LoS amplitude, this saturation in time shift may be accounted for to avoid selecting early peaks in the noise region.

[0120] Tracking covariance

[0121] Positioning algorithms may use linear regression algorithms on the periodic measurements done on the uplink SRS transmitted by the UE. A weighted-least-square (WLS) algorithm may be used to smooth the measurements and track the covariance of the SRS. If measurements are received which do not fit into the expected statistical distribution, it may be discarded. In the case where the UE has a non-zero antenna gain, the positioning algorithm in the gNB may relax the limit on the variance of the SRS amplitude and / or time of arrival of the signal in relation to the max peak.

[0122] Shifting the CIR window

[0123] As illustrated in Figure 10, due to processing limitations, it is not possible to evaluate the full symbol for the LoS peak 101 and hence only a small window 10a around the max peak 102 is used. Depending on the radio architecture, the CIR has to be transported to the processing unit performing the positioning algorithms hence increasing the HW requirements on system interfaces to transport the CIR data.

[0124] Industrial deployments such as aircraft hangars support large indoor spaces where precise positioning is required. An embodiment of the invention is to shift the legacy window 10a, in relation to the max peak 102, to the left of the CIR window, where the time shifted window 10b will include the LoS peak 101. The shift from Tiegto Tpropmay be proportional to the antenna gain.

[0125] The gNB may implement a table which translates antenna gain to nanoseconds of left shift of the CIR window. It is understood that large antenna gain can cause the large late peaks due to strong reflections of distant walls or objects.

[0126] Amplitude Threshold

[0127] One embodiment may be to reduce the amplitude threshold by the same value or scaled value of the antenna gain.

[0128] Another embodiment may be to calculate the average antenna gain over 360 degrees and reduce the amplitude threshold by the same value or scaled value of the antenna gain.

[0129] The embodiments concern the configuration of the LoS detection algorithm and the behavior of the LoS detection algorithm once configured. The LoS detection algorithm may be deployed in Cloud RAN or in the Cloud ENL where the 3GPP core network LMF logical entity resides.

[0130] Embodiments herein such as the embodiments mentioned above will now be further described and exemplified. The text below is applicable to and may be combined with any suitable embodiment described above, some of which may be seen as alternatives, while some may be used in combination. The method comprises the following actions, which actions may be taken in any suitable order. Optional actions are referred to as dashed boxes in the Figures.

[0131] According to an aspect of embodiments herein, as illustrated in Figure 11, the object is achieved by a method performed by a receiver for Line-of-sight, (LoS), path detection in a reception of a signal from a transmitter, the method comprising:

[0132] - Action 11: obtaining 111 an antenna gain of the transmitter;

[0133] Action 12: determining 112 an amplitude threshold and / or a time threshold to be used for the LoS path detection at least according to the obtained antenna gain;

[0134] Action 13: detecting 113 whether at least one smaller peak appears earlier than a max peak of a cross-correlated time domain series of the received signal that applies to the determined threshold(s), wherein the at least one smaller peak applies to the determined threshold(s) comprises: the at least one smaller peak is above the amplitude threshold 13a and / or after the time threshold 13b; and Action 14: determining 116 a peak from the detected peak(s) as possibly associated with the LoS path.

[0135] According to an aspect of embodiments herein it is proposed that when at least one smaller peak 6b has been detected earlier than the max peak 6a, then the earliest peak among the at least one smaller peak may be determined as possibly associated with the LoS path. However, when no smaller peak has been detected earlier than the max peak 6a, then the max peak 6a may be determined as possibly associated with the LoS path.

[0136] Embodiments propose that the antenna gain of the transmitter may be obtained by:

[0137] - Action 11a; requesting the antenna gain of the transmitter from the transmitter, or by

[0138] Action 11b; obtaining the antenna gain based on a type of the transmitter, from antenna gains for different types of transmitters with which the receiver is configured.

[0139] As indicated in Figure 12, proposed embodiments teaches that determining the time threshold Action 12 may comprise:

[0140] Action 12a: determining, based on the max peak, a CIR window of which the earlier bound / starting point is an original time threshold;

[0141] Action 12b: centering, when the obtained antenna gain is zero, the CIR window in relation to the max peak;

[0142] Action 12c: shifting, when the obtained antenna gain is above a set threshold higher than zero, such as 3 dB, the CIR window to the left in the time domain, in which case the time threshold is shifted left and the max peak will appear right shifted in the CIR window, thus increasing the time window for identifying candidate LoS paths; and

[0143] Action 12d: reducing, when the determination dictates a reduction, a minimum amplitude threshold to look for weaker peaks.

[0144] Embodiments propose that determining the time threshold may comprise:

[0145] Action 12e: using a first amplitude threshold that is less than the max peak amplitude if the antenna gain is zero, such as a first set threshold that is 3 dB less than the max peak amplitude if the antenna gain is zero, and

[0146] Action 12f: reducing the amplitude threshold to a second amplitude threshold that is lower than the first amplitude threshold if the antenna gain is higher than zero, such as a second set amplitude threshold that is 6 dB less than the max peak amplitude if the antenna gain is 3 dB, thereby increasing the amplitude window for identifying candidate LoS paths.

[0147] As indicated in Figure 13, embodiments are also proposed where an original window size of the channel impulse response in the time domain may be increased based on the obtained transmitter antenna gain. It is proposed that

[0148] Action 12g: the original CIR window size in the time domain of a first number of points, may be used if the transmitter antenna gain is zero, and that Action 12h: the CIR window size in the time domain may be increased to a second number of points, where the second number is higher than the first number if the antenna gain is higher than zero, such as increasing the first number of points, being 32 points, to the second number of point, being 64 points, if the antenna gain is 3 dB.

[0149] According to an aspect of embodiments herein, the object is achieved by a method performed by a transmitter in communication with a receiver to enable the receiver to perform LoS path detection in the reception of a signal from the transmitter. As indicated in Figure 14, it is proposed that the transmitter:

[0150] - Action 21: receives, from the receiver or another entity in charge of LoS path detection, a request for the antenna gain of the transmitter, and

[0151] - Action 22: transmits, to the receiver or another entity in charge of LoS path detection, the antenna gain of the transmitter.

[0152] According to aspects of embodiments herein it is proposed that in an uplink application, the receiver may be a network TRP, such as a base station 13, 14, and the transmitter may be a UE 12. According to other aspects of embodiments herein it is proposed that in a downlink application, the receiver may be a UE 12 and the transmitter may be a network TRP, such as a base station 13, 14.

[0153] According to an aspect of embodiments herein, as illustrated with renewed reference to Figure 11, the object is achieved by a receiver, adapted to perform a method for Line-of-sight (LoS) path detection in a reception of a signal from a transmitter, wherein the receiver is adapted to:

[0154] obtain, Action 11 , an antenna gain of the transmitter;

[0155] determine, Action 12, an amplitude threshold and / or a time threshold to be used for the LoS path detection at least according to the obtained antenna gain; detect, Action 13, whether at least one smaller peak appears earlier than a max peak of a cross-correlated time domain series of the received signal that applies to the determined threshold(s), wherein the at least one smaller peak applies to the determined threshold(s) comprises: the at least one smaller peak is above the amplitude threshold and / or after the time threshold; and

[0156] determine, Action 14, a peak from the detected peak(s) as possibly associated with the LoS path.

[0157] According to an aspect of embodiments herein, and as illustrated in Figure 6, it is proposed that the receiver may be adapted to determine, Action 12a, the earliest peak 6b among the at least one smaller peak as possibly associated with the LoS path when at least one smaller peak 6b has been detected earlier than the max peak 6a, or to determine the max peak 6a as possibly associated with the LoS path when no smaller peak appears earlier than the max peak.

[0158] One proposed aspect of embodiments herein teaches that the receiver may be adapted to obtain the antenna gain of the transmitter by requesting, Action 11a, from the transmitter, the antenna gain of the transmitter, or by obtaining, Action 11b, the antenna gain based on a type of the transmitter, from antenna gains for different types of transmitters with which the receiver is configured.

[0159] Aspects of embodiments herein are proposed where the receiver, in the determination, Action 12, of the time threshold, may be adapted to:

[0160] determine, Action 12a, based on the max peak, a CIR window of which the earlier bound / starting point is an original time threshold;

[0161] center, Action 12b, when the obtained antenna gain is zero, the CIR window in relation to the max peak; shift, Action 12c, when the obtained antenna gain is above a set threshold higher than zero, such as 3 dB, the CIR window to the left in the time domain, in which case, the time threshold is shifted left and the max peak will appear right shifted in the CIR window, thus increasing the time window for identifying candidate LoS paths; and

[0162] reduce, Action 12d, when the determination dictates a reduction, a minimum amplitude threshold to look for weaker peaks.

[0163] Embodiments propose that, when determining the time threshold, the receiver may be adapted to:

[0164] use, Action 12e, a first amplitude threshold that is less than the max peak amplitude if the transmitter antenna gain is zero, such as a first set threshold that is 3 dB less than the max peak amplitude if the antenna gain is zero, and reduce, Action 12f, the amplitude threshold to a second amplitude threshold that is lower than the first set amplitude threshold if the transmitter antenna gain is higher than zero, such as a second set amplitude threshold that is 6 dB less than the max peak amplitude if the antenna gain is 3 dB, thereby increasing the amplitude window for identifying candidate LoS paths.

[0165] Aspects of embodiments herein are proposed, as indicated in Figure 13, where the receiver may be adapted to increase an original window size of the channel impulse response in the time domain based on the obtained transmitter antenna gain, and this may be done by the receiver being adapted to use, Action 12g, the original CIR window size in the time domain of a first number of points, such as 32 points, if the transmitter antenna gain is zero, and increase, Action 12h, the CIR window size in the time domain to a second number of points, such as 64 points, if the antenna gain is higher than zero, such as 3 dB, where the second number is higher than the first number.

[0166] According to an aspect of embodiments herein, as illustrated in Figure 14, the object is also achieved by a transmitter adapted to be in in communication with a receiver to enable the receiver to perform LoS path detection in the reception of a signal from the transmitter, the transmitter being adapted to:

[0167] receive, Action 21 , from the receiver or other entity in charge of LoS path detection, a request for the antenna gain of the transmitter, and

[0168] transmit, Action 22, to the receiver or other entity in charge of LoS path detection, the antenna gain of the transmitter. According to an aspect of embodiments herein, it is proposed that in an uplink application, the receiver may be a network TRP, such as a base station13, 14, and the transmitter may be a UE 12.

[0169] According to another aspect of embodiments herein, it is proposed that in a downlink application, the receiver may be a UE 12 and the transmitter may be a network TRP, such as a base station 13, 14.

[0170] In this way by using the methods above, the performance of the positioning application in the network or the UE is improved by

[0171] reduced missed detection of the LoS path by extending the time threshold to the left and / or reducing the amplitude threshold, and

[0172] reduced false detection by adjusting the time and amplitude thresholds proportionally to the antenna gain / pattern.

[0173] Embodiments herein may be implemented through a respective processor or one or more processors, such as the respective processor 150 of a processing circuitry in the receiver 15 depicted in Figure 15, and processor 160 of a processing circuitry in the transmitter 16 depicted in Figure 16 together with respective computer program code for performing the functions and actions of the embodiments herein. The program code mentioned above may also be provided as a computer program product, for instance in the form of a data carrier 154, 164 carrying computer program code 153, 163 for performing the embodiments herein when being loaded into the respective receiver 15 and transmitter 16. One such carrier may be in the form of a CD ROM disc. It is however feasible with other data carriers such as a memory stick. The computer program code may furthermore be provided as pure program code on a server and downloaded to the respective receiver 15 and transmitter 16.

[0174] The receiver 15 and transmitter 16 may further comprise a respective memory 152, 162 comprising one or more memory units. The respective memory 152, 162 comprise instructions executable by the processor in the respective receiver 15 and transmitter 16. The respective memory 152, 162 are arranged to be used to store e.g., media functions, indications, tags, information, data, configurations, communication data, and applications to perform the methods herein when being executed in the respective receiver 15 and transmitter 16.

[0175] In some embodiments, a respective computer program 153 and computer program 163 comprise instructions, which when executed by the respective at least one processor 151 , 161 , cause the at least one processor of respective receiver 15 and transmitter 16 to perform the actions above. In some embodiments, a respective carrier 154 and carrier 164 comprises the respective computer program 153 and computer program 163, wherein the respective carrier 154, 164 is one of an electronic signal, an optical signal, an electromagnetic signal, a magnetic signal, an electric signal, a radio signal, a microwave signal, or a computer-readable storage medium.

[0176] Those skilled in the art will appreciate that units in the respective receiver 15 and transmitter 16 described above may refer to a combination of analog and digital circuits, and / or one or more processors configured with software and / or firmware, e.g. stored in the respective receiver 15 and transmitter 16, that when executed by the respective one or more processors such as the processors described above. One or more of these processors, as well as the other digital hardware, may be included in a single Application-Specific Integrated Circuitry ASIC, or several processors and various digital hardware may be distributed among several separate components, whether individually packaged or assembled into a System-on-a-Chip (SoC).

[0177] When using the word "comprise" or “comprising” it shall be interpreted as nonlimiting, i.e. meaning "consist at least of".

[0178] The embodiments herein are not limited to the preferred embodiments described above. Various alternatives, modifications and equivalents may be used.

[0179] Abbreviations

[0180] 5G NR 5G Ny Radio

[0181] AGV Automated Guided Vehicle

[0182] AMF Access and Mobility Management Function

[0183] AoA Angle of Arrival

[0184] AoD Angle of Departure

[0185] ASA Abort Session Answer

[0186] ASR Abort Session Request

[0187] BS Base Station

[0188] CIR Channel Impulse Response

[0189] CS GSM / WCDMA Circuit Switched (CS)

[0190] DL Downlink

[0191] eClD Enhanced Cell ID

[0192] eNB eNodeB (LTE Base Station)

[0193] ENL Ericsson Network Location server

[0194] EPS FB Evolved Packet System Fallback E-SMLC Enhanced Serving Mobile Location Center

[0195] gNB gNodeB (5G Base Station)

[0196] IMS IP Multimedia Subsystem (IMS) telephony service engine LMF Location Management Function

[0197] LoS Line of Sight

[0198] LPP LTE Positioning Protocol

[0199] LTE Long Term Evolution

[0200] MTAS Multimedia Telephony Application Server

[0201] NG-C Next Generation Control

[0202] NG-RAN Next Generation Radio Access Network

[0203] NLoS Non Line of Sight

[0204] NRPPa NR positioning protocol A

[0205] PS Packet Switch Domain

[0206] PRS Positioning Reference Signal

[0207] RRC Radio Resource Control

[0208] RSRP Reference Signal Received Power

[0209] RSTD Reference Signal Time Difference

[0210] RTT Round Trip Time

[0211] SLP Service Location Protocol

[0212] SRS Sounding Reference Signal

[0213] TDoA Time-Difference-of-Arrival

[0214] TA Timing Advance

[0215] ToA Time-of-Arrival

[0216] TP Transmission Point

[0217] TRP Transmission Reception Point

[0218] UE User Equipment

[0219] UL Uplink

[0220] UTDoA Uplink Time-Difference-of-Arrival

Claims

CLAIMS1. A method performed by a receiver (15) for Line-of-sight, LoS, path detection in a reception of a signal from a transmitter (16), the method comprising:- obtaining (11) an antenna gain of the transmitter;- determining (12) an amplitude threshold and / or a time threshold to be used for the LoS path detection at least according to the obtained antenna gain;- detecting (13) whether at least one smaller peak appears earlier than a max peak of a cross-correlated time domain series of the received signal that applies to the determined threshold(s), wherein the at least one smaller peak applies to the determined threshold(s) comprises: the at least one smaller peak is above the amplitude threshold and / or after the time threshold; and - determining (14) a peak from the detected peak(s) as possibly associated with the LoS path.

2. The method according to claim 1, the method comprising:- determining, when at least one smaller peak has been detected earlier than the max peak, the earliest peak among the at least one smaller peak as possibly associated with the LoS path.

3. The method according to claim 1, the method comprising:- determining, when no smaller peak has been detected earlier than the max peak, the max peak as possibly associated with the LoS path.

4. The method according to any preceding claim, the method comprising obtaining the antenna gain of the transmitter by:- requesting (11a), from the transmitter, the antenna gain of the transmitter, or- obtaining (11b) the antenna gain based on a type of the transmitter, from antenna gains for different types of transmitters with which the receiver is configured.

5. The method according to any preceding claim, where determining the time threshold comprises:- determining, based on the max peak, a Channel Impulse Response, CIR, window of which the earlier bound / starting point is an original time threshold;- centering, when the obtained antenna gain is zero, the CIR window in relation to the max peak;- shifting, when the obtained antenna gain is above a set threshold higher than zero, the CIR window to the left in the time domain; and- reducing, when the determination dictates a reduction, a minimum amplitude threshold to look for weaker peaks.

6. The method according to claim 5, the method comprising:- using a first amplitude threshold that is less than the max peak amplitude if the antenna gain is zero; and- reducing the amplitude threshold to a second amplitude threshold that is lower than the first amplitude threshold if the antenna gain is higher than zero.

7. The method according to any preceding claim, the method comprising:- increasing an original window size of the channel impulse response in the time domain based on the obtained transmitter antenna gain.

8. The method according to claim 7, the method comprising:- using the original CIR window size in the time domain of a first number of points if the transmitter antenna gain is zero, and- increasing the CIR window size in the time domain to a second number of points if the antenna gain is higher than zero where the second number is higher than the first number.

9. A method performed by a transmitter (16) in communication with a receiver (15) to enable the receiver (15) to perform Line-of-sight, LoS, path detection in a reception of a signal from the transmitter (16), the method comprising:- receiving (21), from the receiver or other entity in charge of LoS path detection, a request for the antenna gain of the transmitter, and- transmitting (22), to the receiver or other entity in charge of LoS path detection, the antenna gain of the transmitter.

10. A method according to any preceding claim, wherein the receiver is a network Transmission Reception Point, TRP, and the transmitter is a User Equipment, UE.

11. A method according to any one of claims 1 to 9, wherein the receiver is a UE and the transmitter is a network Transmission Reception Point, TRP.

12. A receiver (15), adapted to perform a method for Line-of-sight, LoS, path detection in a reception of a signal from a transmitter (16), wherein the receiver is adapted to:- obtain an antenna gain of the transmitter;- determine an amplitude threshold and / or a time threshold to be used for the LoS path detection at least according to the obtained antenna gain;- detect whether at least one smaller peak appears earlier than a max peak of a cross-correlated time domain series of the received signal that applies to the determined threshold(s), wherein the at least one smaller peak applies to the determined threshold(s) comprises: the at least one smaller peak is above the amplitude threshold and / or after the time threshold; and- determine a peak from the detected peak(s) as possibly associated with the LoS path.

13. The receiver according to claim 12, the receiver being adapted to:- determine the earliest peak among the at least one smaller peak as possibly associated with the LoS path when at least one smaller peak has been detected earlier than the max peak.

14. The receiver according to claim 12, the receiver being adapted to:- determine the max peak as possibly associated with the LoS path when no smaller peak appears earlier than the max peak.

15. The receiver according to any one of claims 12 to 14, the receiver being adapted to:- request, from the transmitter, the antenna gain of the transmitter, or- obtain the antenna gain based on a type of the transmitter, from antenna gains for different types of transmitters with which the receiver is configured.

16. The receiver according to any one of claims 12 to 15, the receiver being adapted to, in the determination of the time threshold:- determine, based on the max peak, a Channel Impulse Response, CIR, window of which the earlier bound / starting point is an original time threshold;- center, when the obtained antenna gain is zero, the CIR window in relation to the max peak;- shift, when the obtained antenna gain is above a set threshold higher than zero, the CIR window to the left in the time domain; and- reduce, when the determination dictates a reduction, a minimum amplitude threshold to look for weaker peaks.

17. The receiver according to claim 16, the receiver being adapted to:- use a first amplitude threshold that is less than the max peak amplitude if the transmitter antenna gain is zero; and- reduce the amplitude threshold to a second amplitude threshold that is lower than the first set amplitude threshold if the transmitter antenna gain is higher than zero.

18. The receiver according to any one of claims 12 to 17, the receiver being adapted to:- increase an original window size of the channel impulse response in the time domain based on the obtained transmitter antenna gain.

19. The receiver according to claim 18, the receiver being adapted to:- use the original CIR window size in the time domain of a first number of points if the transmitter antenna gain is zero, and- increase the CIR window size in the time domain to a second number of points if the antenna gain is higher than zero, where the second number is higher than the first number.

20. A transmitter (16) adapted to be in in communication with a receiver (15) to enable the receiver to perform Line-of-sight, LoS, path detection in a reception of a signal from the transmitter, the transmitter being adapted to:- receive, from the receiver or other entity in charge of LoS path detection, a request for the antenna gain of the transmitter, and- transmit, to the receiver or other entity in charge of LoS path detection, the antenna gain of the transmitter.

21. A receiver according to any one of claims 12 to 19, wherein the receiver is a network Transmission Reception Point, TRP, and the transmitter is a User Equipment, UE.

22. A receiver according to any one of claims 12 to 19, wherein the receiver is a UE and the transmitter is a network Transmission Reception Point, TRP.

23. A computer program comprising instructions, which when executed by a processor, causes the processor to perform the method according to any of the claims 1-11 , as performed by the receiver or the transmitter, respectively.

24. A carrier comprising the computer program of claim 23, wherein the carrier is one of an electronic signal, an optical signal, an electromagnetic signal, a magnetic signal, an electric signal, a radio signal, a microwave signal, or a computer-readable storage medium.

Images