Cir peak threshold control for toa estimation

Abstract

A threshold condition formed with respect to the strongest peak (e.g., in a signaled DL-PRS specific search window) is used to search for a first peak to be used for time of arrival (TOA) estimation. This threshold condition can be used with uniform or non-uniform DL-PRS, and with or without incorporation of cyclic shifts in each of these DL-PRS. In doing so, the solutions presented herein (100, 200, 300, 400) avoid detection of false peaks.

Description

[0001] Related applications

[0002] This application claims priority to U.S. Application No. 63 / 059381, filed July 31, 2020, the disclosure of which is incorporated herein by reference in its entirety. Background Technology

[0003] Location has been a central theme in the Long Term Evolution (LTE) standardization process since 3GPP Release 9. While the initial primary goal was to meet regulatory requirements for emergency call location, other use cases, such as location for the Industrial Internet of Things (I-IoT), are becoming increasingly important. For example, Figure 1 The architecture shown supports positioning in New Radio (NR). The Location Management Function (LMF) is the location node in NR. There is also interaction between the location node and the gNodeB via NR Positioning Protocol A (NRPPa). Interaction between the gNodeB and the device is supported via the Radio Resource Control (RRC) protocol, while the location node interfaces with the User Equipment (UE) via the LTE Positioning Protocol (LPP). LPP is common to both NR and LTE. It will be understood that, although... Figure 1 Both gNB and ng-eNB are shown, but both may not always be present. Additionally, when both gNB and ng-eNB are present, NG-C is usually only present for one of them.

[0004] The traditional LTE standard supports the following technologies:

[0005] Enhanced cell ID. Essentially, it's cell ID information used to associate a device with the service area of ​​a serving cell, followed by additional information to determine a finer-grained location.

[0006] Assisted Global Navigation Satellite System (GNSS). GNSS information retrieved by the device and supported by auxiliary information provided to the device from the Evolved Serving Mobile Positioning Center (E-SMLC).

[0007] Observed Time Difference of Arrival (OTDOA). The device estimates the time difference of reference signals from different base stations and sends it to the E-SMLC for multi-point positioning.

[0008] UTDOA (Uplink TDOA) requests the UE to transmit specific waveforms detected by multiple location measurement units (e.g., eNBs) at known locations. These measurements are forwarded to the E-SMLC for multipoint positioning.

[0009] In NR version 16, several location features were specified.

[0010] A new downlink (DL) reference signal, the NR DL Positioning Reference Signal (PRS), has been designated. The main benefit of this signal, in relation to the LTE DL PRS, is the increased bandwidth configurable to 24 to 272 radio bearers (RBs), which significantly improves TOA accuracy. The NR DL PRS can be configured with a comb factor of 2, 4, 6, or 12, with comb-12 allowing twice the orthogonal signal size of comb-6 LTE PRS. The NR DL PRS can also perform beam scanning.

[0011] Enhancements to the NR UL Sound Reference Signal (SRS) are specified in NR Release 16. The NRSRS for positioning in Release 16 allows for longer signals, up to 12 symbols (compared to 4 symbols in Release 15), and flexible placement within time slots (only the last six symbols of a time slot can be used in the Release 15 SRS). It also allows interleaved comb resource element (RE) modes for improved TOA measurement range and more orthogonal signals based on comb offsets (comb 2, 4, and 8) and cyclic shifts. However, Release 16 does not support cyclic shifts longer than those of orthogonal frequency division multiplexing (OFDM) symbols divided by the comb factor, although this is a major advantage of interleaved combs, at least in indoor scenarios. Power control based on neighboring cell synchronization signal blocks (SSBs) / DL PRS and spatial quasi-correspondence (QCL) relationships toward the Channel State Information Reference Signal (CSI-RS), SSB, DL PRS, or another sound reference signal (SRS) are supported.

[0012] In NR version 16, the following UE measurements were specified.

[0013] DL Reference Signal Time Difference (RSTD) allows for positioning such as DL TDOA.

[0014] Multi-cell UE Rx-Tx time difference measurement, allowing multi-cell round-trip time (RTT) measurement.

[0015] DL PRS Reference Signal Received Power (RSRP)

[0016] In NR version 16, the following gNB measurements were specified.

[0017] Uplink relative time of arrival (UL-RTOA) can be used for UL TDOA positioning.

[0018] gNb Rx-Tx time difference can be used for multi-cell RTT measurements.

[0019] UL SRS-RSRP

[0020] Angle of arrival (AoA) and angle of arrival at zenith (ZoA)

[0021] In December 2019, a research project on NR version 17, focusing on I-IoT scenarios for positioning, was launched. To meet the stringent accuracy requirements associated with I-IoT, a key issue that needs to be overcome is the positioning error caused by the UE's TX timing error, which affects the accuracy of the UE's Rx-Tx time difference measurement.

[0022] In NR Release 17, the topic of positioning integrity—that is, considering both accuracy and reliability in positioning solutions—will be discussed for the first time in 3GPP. While the topic of integrity has been previously studied for Radio Access Technology (RAT) independent positioning methods (e.g., GNSS), the key performance indicators (KPIs) for positioning integrity for RAT-based positioning methods are also considered within this scope in the solution proposed in this paper.

[0023] The time-based OFDM symbol can be written as the subcarrier symbol c. k The Fourier expansion is shown below:

[0024]

[0025] Where T represents the OFDM symbol time, and Δf = 1 / T represents the subcarrier spacing. Note that the Fourier expansion basis function e j·2π·k·Δf·t The cycle is:

[0026]

[0027] Apart from constant basis functions (k=0).

[0028] For a comb-shaped n-signal with zero subcarrier offset, for some integer m, only for k = n*m, we have c k ≠0. Then, c k All basis functions ≠ 0 are periodic with a period of T / n, therefore h(t) is periodic with a period of T / n. This can also be seen from the fact that the Fourier expansion can be reinterpreted as a Fourier expansion with a subcarrier spacing of n·Δf and an OFDM symbol length of T / n (removing terms that are zero in any case).

[0029] For a comb-shaped n-signal with subcarrier offset s, for some integer m, only for k = s + n*m, we have c k ≠0. By extracting the factor e from the Fourier expansion. j·2π·s·Δf·t We see:

[0030] h(t) = e j·2π·s·Δf·t ·g(t)

[0031] Wherein, g(t) is periodic with a period of T / n.

[0032] To estimate the TOA, the UE can first estimate the channel impulse response and then identify the first peak in the power delay distribution of the channel impulse response (CIR). CIR estimation can be performed in many different ways, for example, in the time domain by a loop associated with a known transmitted signal or (mathematically equivalently) in the frequency domain by the following steps:

[0033] Fast Fourier Transform (FFT) to Frequency Domain

[0034] Multiply each subcarrier symbol by the complex conjugate of the corresponding subcarrier symbol of the known transmitted signal.

[0035] If the known transmitted signal does not have a constant amplitude in the frequency domain, then it is also necessary to divide by the amplitude of the known signal for each subcarrier.

[0036] Inverse Fast Fourier Transform (IFFT) back to the time domain

[0037] CIR can also be estimated by non-cyclic correlation with known transmitted signals, which gives roughly the same result as cyclic correlation for delays with a small symbol length.

[0038] If cyclic correlation (or an equivalent method in the frequency domain) is used, the known periodicity of the transmitted signal (up to phase rotation) will result in a corresponding periodicity (up to phase rotation) in the CIR estimate. This is easily understood because the channel impulse response itself will be a comb-n signal. Therefore, the CIR can be written as:

[0039] h(t) = e j·2π·s·Δf·t ·g(t)

[0040] Wherein, g(t) is periodic with a period of T / n.

[0041] Furthermore, when using acyclic correlation methods to estimate CIR, spurious peaks appear in a similar manner due to the known periodic structure of the transmitted signal, such as... Figure 2 As shown, Figure 2 The absolute values ​​of the correlation between the known transmitted comb-4 signal and the signal received through an additive white Gaussian noise (AWGN) channel are shown. These peaks will be suppressed relative to the dominant peak, but not significantly. th The suppression of the additional peak is approximately a multiple of (nm) / n.

[0042] For a typical comb-n signal h(t), we have:

[0043] h(t) = e j·2π·s·Δf·t ·g(t)

[0044] Where g(t) is periodic with a period of T / n. Autocorrelation can be written as:

[0045]

[0046] Because of the phase factor e j·2π·s·Δf·τ The autocorrelation amplitude is not affected, so a typical comb signal will also have an additional peak with a time offset of m·(T / n) relative to the main peak of the same size as the periodic function. Considering the cyclic prefix (CP), the additional correlation peak will be suppressed to some extent, but it will not be much more significant as long as the CP length is much shorter than the OFDM symbol length.

[0047] Regardless of whether TOA estimation is based on linear or cyclic (CIR) correlation, the measurement range must be limited to a TOA interval of length T / n to avoid misdetecting side peaks as actual peaks. Even with this limitation on the measurement range, channel peaks with large delays can still be periodically mapped into the UE search window and incorrectly detected as the first peak. Therefore, improved peak detection is still needed for TOA. Summary of the Invention

[0048] The solution proposed in this paper searches for the first peak to be used for time of arrival (TOA) estimation using a threshold condition relative to the formation of the strongest peak (e.g., within a specific search window of the DL-PRS transmitted with the signal). This threshold condition can be used with uniform or non-uniform DL-PRS, and in each of these DL-PRS, with or without cyclic shifting. The main advantage in all cases is the avoidance of detecting false peaks.

[0049] An exemplary embodiment includes a method for estimating the Time of Arrival (TOA) from a wireless node in a wireless communication network. The method includes: receiving one or more reference signals from one or more remote wireless nodes, and estimating the Channel Impulse Response (CIR) in response to the received one or more reference signals. The method further includes identifying a first peak in time of the CIR that satisfies a threshold condition within a search window as the TOA peak. The threshold condition is defined in response to the intensity of the dominant peak of the CIR within the search window. The method further includes estimating the TOA based on the TOA peak.

[0050] In an exemplary embodiment, the threshold condition is whether the candidate peaks of the CIR within the search window exceed a peak threshold defined in response to the intensity of the dominant peak.

[0051] In an exemplary embodiment, a peak threshold is defined in response to the intensity of the dominant peak and an adjustment value.

[0052] In an exemplary embodiment, the peak threshold is defined as the intensity of the dominant peak that is reduced by the adjusted value.

[0053] In an exemplary embodiment, a peak threshold is defined in response to the intensity of the dominant peak and an adjustment function, the adjustment function being a function of the time difference between the dominant peak time and the candidate peak time.

[0054] In an exemplary embodiment, the adjustment function also includes a function of the time difference between the dominant peak time and the candidate peak time, modified by the adjustment value.

[0055] In an exemplary embodiment, the adjustment function includes a function that is inversely proportional to the square of the time difference.

[0056] In an exemplary embodiment, the peak threshold includes: a candidate peak threshold for each candidate peak in a search window containing the dominant peak, wherein each candidate peak threshold is defined in response to an adjustment function and the intensities of the corresponding candidate peak and all previous peaks in the search window, and a corresponding adjustment function for each of the previous peaks. The adjustment function includes a function of the time difference between the candidate peak and its corresponding previous peak. Additionally, identifying the first peak in time within the search window that satisfies the threshold condition as a TOA peak includes: iteratively comparing the intensity of each candidate peak with the corresponding candidate peak threshold condition until no earlier candidate peak exceeds the corresponding candidate peak threshold; and identifying the last candidate peak exceeding the corresponding candidate peak threshold as a TOA peak.

[0057] An exemplary embodiment also includes calculating a peak threshold.

[0058] An exemplary embodiment also includes receiving an adjustment value from at least one of one or more remote wireless nodes or from another node within the wireless communication network.

[0059] An exemplary embodiment also includes determining an adjustment value in response to one or more rules pre-configured for the wireless node. In an exemplary embodiment, the one or more rules include one or more rules pre-configured for each positioning reference signal, for each remote wireless node, and / or for each frequency.

[0060] In an exemplary embodiment, the adjustment value is determined based on a reference adjustment value and one or more compensation factors.

[0061] In an exemplary embodiment, one or more compensation factors are associated with a reference signal configuration for a reference signal, and the CIR is estimated for the reference signal.

[0062] An exemplary embodiment also includes using one or more compensation factors to adjust a reference adjustment value to determine an adjustment value.

[0063] An exemplary embodiment also includes receiving a reference adjustment value from at least one of one or more remote wireless nodes or from another node within the wireless communication network.

[0064] An exemplary embodiment also includes receiving one or more threshold adjustments from at least one of one or more remote wireless nodes or from another node within the wireless communication network.

[0065] In an exemplary embodiment, defining threshold conditions includes defining threshold conditions in response to one or more rules pre-configured for the wireless node.

[0066] In an exemplary embodiment, one or more rules include one or more rules pre-configured for each positioning reference signal, pre-configured for each remote wireless node, and / or pre-configured for each frequency.

[0067] In an exemplary embodiment, a peak threshold is calculated in response to the intensity of the dominant peak and at least one of the following: the size of the search window; the number of one or more reference signals received from one or more remote wireless nodes; the comb configuration of each of the one or more received reference signals; the frequency of the reference signal density; the time of the reference signal density; the bandwidth of the reference signal; the number of times the reference signal repeats within the reference signal period; and one or more characteristics of the wireless channel through which the one or more reference signals are transmitted to the wireless nodes.

[0068] An exemplary embodiment further includes coherently and jointly processing reference signals received via multiple frequency layers, wherein estimating the CIR includes estimating the CIR within a search window in response to the coherently and jointly processed reference signals.

[0069] In an exemplary embodiment, coherently and jointly processing reference signals received via multiple frequency layers includes first coherently and jointly processing reference signals received from a first remote wireless node via a first plurality of frequency layers, and second coherently and jointly processing reference signals received from a second remote wireless node via a second plurality of frequency layers. Additionally, estimating the CIR includes estimating a first CIR within a search window in response to the first coherently and jointly processed reference signals, and estimating a second CIR within the search window in response to the second coherently and jointly processed reference signals. Furthermore, defining threshold conditions includes defining a first threshold condition in response to the intensity of the dominant peak of the first CIR within the search window, and defining a second threshold condition in response to the intensity of the dominant peak of the second CIR within the search window.

[0070] In an exemplary embodiment, the intensity of any peak in the search window includes: the peak in the power delay distribution of the CIR at a given sampling frequency; the peak in the power delay distribution of the CIR after interpolation between samples; the power delay distribution of the CIR integrated over a time period around the corresponding peak; the power delay distribution of the CIR summed over several samples around the corresponding peak; and the power delay distribution of the CIR averaged over several samples around the corresponding peak.

[0071] In an exemplary embodiment, the power delay distribution includes the absolute square of the CIR.

[0072] In an exemplary embodiment, the power delay distribution includes the absolute value of the CIR.

[0073] In an exemplary embodiment, at least one of the one or more remote wireless nodes includes a network node, and wherein receiving one or more reference signals includes receiving one or more downlink reference signals from the network node.

[0074] In an exemplary embodiment, at least one of the one or more remote wireless nodes includes a user equipment (UE), and wherein receiving one or more reference signals includes receiving one or more uplink reference signals from the UE.

[0075] An exemplary embodiment includes a wireless node in a wireless communication system configured to estimate the Time of Arrival (TOA) or one or more reference signals received from one or more remote wireless nodes. The wireless node includes one or more processing circuitry configured to: receive the one or more reference signals from the one or more remote wireless nodes, and estimate the Channel Impulse Response (CIR) in response to the received one or more reference signals. The one or more processing circuitry is further configured to identify a first peak in time of the CIR that satisfies a threshold condition within a search window as the TOA peak. The threshold condition is defined in response to the intensity of the dominant peak of the CIR within the search window. The one or more processing circuitry is further configured to estimate the TOA based on the TOA peak.

[0076] An exemplary embodiment includes a computer program product for controlling a wireless node. The computer program product includes software instructions that, when executed on at least one processing circuitry in the wireless node, cause the wireless node to receive one or more reference signals from one or more remote wireless nodes and to estimate the channel impulse response (CIR) in response to the received one or more reference signals. When executed on at least one processing circuitry, the software instructions also cause the wireless node to identify a first peak in time of the CIR that satisfies a threshold condition within a search window as a TOA peak. The threshold condition is defined in response to the intensity of the dominant peak of the CIR within the search window. When executed on at least one processing circuitry, the software instructions also cause the wireless node to estimate the TOA based on the TOA peak. In an exemplary embodiment, a computer-readable medium includes the computer program product. In an exemplary embodiment, the computer-readable medium includes a non-transitory computer-readable medium.

[0077] An exemplary embodiment includes a method performed by a wireless device in a communication network. The method includes receiving a reference signal from a node within the communication network. The method further includes receiving an indication of a threshold parameter representing an adjustment to a set of one or more paths of the channel impulse response (CIR) of the reference signal to be applied by the wireless device to generate a path detection threshold for detecting a first path of the CIR in time within a search window.

[0078] An exemplary embodiment further includes the step of: using a threshold parameter to calculate the arrival time of a reference signal based on a first path in the time frame of the CIR exceeding the path detection threshold within the search window.

[0079] In an exemplary embodiment, the indication of the threshold parameter is received as part of the auxiliary data of the reference signal.

[0080] In an exemplary embodiment, the auxiliary data also includes the duration of the search window.

[0081] An exemplary embodiment also includes receiving an indication of a threshold parameter that represents an adjustment to be applied to the strongest path of the CIR response within the search window.

[0082] An exemplary embodiment includes a method performed by a network node in a communication network. The method includes transmitting a reference signal to a wireless device within the communication network. The method further includes transmitting an indication of a threshold parameter representing an adjustment to be applied by the wireless device to a set of one or more paths of the channel impulse response (CIR) of the reference signal to generate a path detection threshold for detecting a first path of the CIR in time within a search window.

[0083] In an exemplary embodiment, the indication of the threshold parameter is transmitted as part of the auxiliary data of the reference signal.

[0084] In an exemplary embodiment, the auxiliary data also includes the duration of the search window.

[0085] An exemplary embodiment also includes an indication to send a threshold parameter that represents an adjustment to be applied to the strongest path of the CIR response within the search window. Attached Figure Description

[0086] Figure 1 A block diagram of an exemplary communication network applicable to the solution proposed herein is shown.

[0087] Figure 2 This demonstrates the possible false peaks that may occur in an exemplary CIR.

[0088] Figure 3 An exemplary method according to an embodiment of the solution proposed herein is shown.

[0089] Figure 4 An exemplary power delay distribution is shown.

[0090] Figure 5 An exemplary embodiment of the solution proposed herein is shown. Figure 4 An example of determining the threshold for the power delay distribution.

[0091] Figure 6 An exemplary CIR and corresponding threshold conditions are shown according to an exemplary embodiment of the solution proposed herein.

[0092] Figure 7 An exemplary embodiment of the solution proposed herein is shown. Figure 4 Another example of determining the threshold for the power delay distribution.

[0093] Figure 8 Exemplary PRS resources for several UEs applicable to the solution proposed herein are shown.

[0094] Figure 9 Another exemplary method according to an embodiment of the solution proposed herein is shown.

[0095] Figure 10 Another exemplary method according to an embodiment of the solution proposed herein is shown.

[0096] Figure 11 A block diagram of an exemplary wireless node according to an embodiment of the solution proposed herein is shown. Detailed Implementation

[0097] Conventional TOA (Time of Alignment) technology has various problems. For example, the following scenarios may lead to large positioning errors:

[0098] For non-interlaced or incompletely interlaced DL PRS, the side peaks in the estimated CIR may be misdetected as the actual peaks.

[0099] For interleaved DL PRS coherently combined with Doppler extended forbidden interleaving, the side peaks in the estimated CIR may be misdetected as the actual peaks.

[0100] For fully interleaved DL PRS that are coherently combined to achieve frequency uniformity, side peaks in the estimated CIR may be misdetected as actual peaks, which can lead to large positioning errors if the delay is long (i.e., greater than the symbol time).

[0101] Due to distortion of the transmitted DL PRS caused by factors such as D / A converters, filters, or pulse shaping, the side peaks in the estimated CIR may be misdetected as the actual peaks.

[0102] Due to the limited bandwidth of the transmitted signal, the side peak in the estimated CIR may be misdetected as the actual peak.

[0103] Side peak issues preclude the use of non-uniform frequency DL PRS, such as a one-symbol comb-12 signal, which in turn leads to reduced positioning performance or increased positioning overhead in some scenarios (e.g., indoor scenarios).

[0104] Side peaks are one of the sources of reduced reliability and integrity of positioning estimates, as they may be misdetected as actual peaks.

[0105] Problems also exist when constructing different DL-PRSs by applying different cyclic shifts (CS) to a common signal of uniform or non-uniform frequencies. Because DL-PRSs differ only in cyclic shift, the individual estimated CIRs can also be cyclically shifted accordingly, and the UE can observe a single long CIR consisting of the superposition of all the basic CIRs in the first instance. To correctly process the received PRS, the UE must therefore segment the time axis into distinct parts corresponding to the true CIRs of each PRS, and then use each segment to determine its first path. However, there is a risk of not completing this segmentation completely correctly, which could lead to later components being incorrectly identified as the first path of subsequent CIRs.

[0106] According to the solution proposed herein, for TOA estimation, such as for RSTD or UE Rx-TX time difference measurement or for reference cell or reference PRS, the UE detects a first CIR peak whose power is higher than a threshold relative to the strongest detected peak in the CIR (the CIR peak may also be referred to herein as a "path"). In one embodiment, the relative threshold is configured via signaling (e.g., via LPP). In one embodiment, the relative threshold is pre-configured as a fixed value or depends on the value of other configuration parameters (e.g., configuration parameters of the DL PRS used for TOA estimation). In one embodiment, the threshold is a function of the temporal distance (delay) between the potential first peak and the strongest peak. In one embodiment, the threshold is based on multiple detected peaks, and the threshold is calculated based on the temporal distance (delay) between the potential first peak and other peaks, as well as the intensity of other peaks. In one embodiment, the use of the peak intensity threshold as described above is combined with the use of frequency non-uniform DL PRS (e.g., a symbolic comb-12 signal). In one embodiment, the threshold is a function of the positioning integrity or KPI of the network or device in terms of positioning estimation. These embodiments are described for DL ​​measurements, but are also applicable to UL measurements at radio network nodes (e.g., gNB, transmit-receive point (TRP), LMU, etc., rather than at the UE). Thresholds can be determined by the network node (e.g., based on similar rules described for the UE) via NRPPa or other relevant protocols, or configured by another node (e.g., by the LMF or control network node).

[0107] Figure 3 An exemplary method 100 for estimating Time of Arrival (TOA) by a wireless node in a wireless communication network is illustrated, representing a solution according to each embodiment of these embodiments broadly presented herein. Method 100 can be implemented by any wireless node in the wireless communication network (including, but not limited to, UE, LMF, base station node (e.g., gNB or ng-eNB)). Method 100 includes receiving one or more reference signals from one or more remote wireless nodes (box 110) and estimating the CIR in response to the received one or more reference signals (box 120). Method 100 also includes identifying a first temporal peak (e.g., the earliest temporal peak within the search window) that satisfies a threshold condition within a search window as the TOA peak (box 130). The threshold condition is defined in response to the intensity of the dominant peak of the CIR within the search window. Method 100 also includes estimating the TOA based on the TOA peak (box 140). Further details of each embodiment of the various embodiments of the solutions presented herein are provided below.

[0108] Broadly speaking, for the TOA measurement used, such as for UE RSTD measurement or UE RX-TX time difference measurement, the UE first estimates the CIR and then identifies the earliest peak in the power delay distribution of the estimated CIR. The search for the first peak is limited to a temporal search window, for example, sent to the UE via LPP signaling, as defined for NR in Release 16. The temporal position of the first peak within the search window defines the TOA of the PRS. The solution proposed in this paper restricts the UE search for the first peak to peaks that satisfy a threshold condition that depends on the strength of the strongest peak (i.e., the dominant peak) within the search window, and in some embodiments, also on the temporal position of the dominant peak or relative to a set of stronger peaks.

[0109] In one exemplary embodiment, the threshold condition is a threshold relative to the intensity of the dominant peak (i.e., the strongest peak) and represents a threshold condition independent of delay. A candidate peak in the CIR is detected as a peak if, on a logarithmic scale, the intensity of the candidate peak is greater than the dominant peak intensity minus an adjustment value (e.g., derived from a relative threshold). On a linear scale, this can be equivalently written as:

[0110] P candidate_peak >R·P dom_peak

[0111] Where R represents the adjustment value, P dom_peak Indicates the dominant peak intensity, and P candidate_peak This represents the candidate peak intensity. For example, R can be given by the following formula:

[0112] R = 10 -relative_threshold_value / 10

[0113] The parameters transmitted by the signal or determined by the UE according to the rules described herein can be R, or any parameter used to derive R. This type of threshold helps to reject peaks in the estimated CIR that occur at erroneous delays because the delay is longer than the measurement range, as they are periodically mapped to the measurement range, such as the background portion and... Figure 4 As described above. Such peaks with large delays are typically much weaker than the strongest peak, and therefore can be effectively rejected using a threshold relative to the strongest peak (e.g., a threshold defined using the strongest peak). More specifically, Figure 4An example of estimated power delay distribution based on a single-symbol comb-4 reference signal with a bandwidth of 100 MHz and a subcarrier spacing of 30 kHz is shown, which is estimated using 4096 samples per OFDM symbol. Due to the comb-4 structure, the estimated power delay distribution is periodic, with a period of one-quarter of the OFDM symbol length. The TOA measurement range is therefore also limited to one-quarter of the OFDM symbol length. Channel peaks with delays exceeding the measurement range are periodically mapped to the measurement range (the first quarter of the power delay distribution) and may be falsely detected as the first false peak. This type of threshold can also be used to reject side peaks, but since the threshold is independent of delay, it does not take advantage of the fact that side peaks weaken with distance from the actual channel peaks (in terms of delay).

[0114] From the UE's perspective, TOA estimation can then be performed as follows:

[0115] The UE is configured with several DL PRS via LPP, including parameters that define the search window (e.g., as defined for NR in version 16) and parameters that define the threshold (unless pre-configured).

[0116] The UE is configured via LPP to perform RSTD and / or UE Rx-Tx time difference measurements based on the configured DL PRS.

[0117] For each DL PRS, the UE estimates the CIR within the search window.

[0118] The UE identifies the strongest peak in the CIR power delay distribution within the search window.

[0119] The UE estimates the intensity of the strongest peak identified in the CIR power delay distribution within the search window.

[0120] The UE identifies the first peak in the CIR power delay distribution within the search window that is higher than a threshold relative to the strongest peak, for example, candidate peak intensity > strongest peak intensity - adjustment value.

[0121] The UE reports RSTD and / or UE Rx-Tx time difference measurements based on the first peak identified in the CIR power delay distribution within the search window that is higher than a threshold relative to the strongest peak.

[0122] The threshold relative to the intensity of the strongest peak can also be combined with a threshold relative to the estimated noise level. This can be useful because, to some extent, they serve different purposes (the purpose of the threshold relative to the estimated noise level is to reject noise peaks), as further described below.

[0123] In another exemplary embodiment, the threshold is a delay-related threshold relative to the dominant peak. For example, a candidate peak can be detected as a peak if (on a linear scale) it satisfies the following threshold condition:

[0124] P candidate_peak >R·f(τ)·P dom_peak

[0125] Where τ represents the time difference between the dominant peak and the candidate peak. In one embodiment, the adjustment function f(τ) can be expressed as:

[0126]

[0127] Where a is a constant. It will be understood that although the adjustment value R is shown as separate from the adjustment function, the threshold condition can alternatively be expressed as:

[0128] P candidate_peak >f(τ)·P dom_peak ,

[0129] The adjustment function f(τ) is alternatively expressed as:

[0130]

[0131] The constant 'a' can be set to 1 in some examples because 'a' can be absorbed into R. It is still convenient to set 'a' to 1 / BW. 2 The value is on the order of magnitude, where BW represents the bandwidth of the DL PRS or alternatively the system bandwidth, and R is signaled on a linear or logarithmic scale. Alternatively, both a and R can be pre-configured. The parameter signaled or determined by the UE according to the rules described for this embodiment can be R, f, or any parameter used to derive R, f, or a combination of R·f(τ). Importantly, note that an ideal low-pass filter can be expressed as:

[0132]

[0133] It corresponds to sinc(BW·τ) in the time domain, and:

[0134]

[0135] From the UE's perspective, TOA estimation can then be performed, for example, as follows:

[0136] The UE is configured with several DL PRS via LPP, including parameters that define the search window (e.g., as defined for NR in version 16) and parameters that define the threshold (unless pre-configured).

[0137] The UE is configured via LPP to perform RSTD and / or UE Rx-Tx time difference measurements based on the configured DL PRS.

[0138] For each DL PRS, the UE estimates the CIR within the search window.

[0139] The UE identifies the strongest peak in the CIR power delay distribution within the search window as the dominant peak.

[0140] The UE estimates the intensity P of the strongest peak identified in the CIR power delay distribution within the search window. dom_peak .

[0141] The UE identifies the first peak value in the CIR power delay distribution within the search window that meets the threshold condition:

[0142] P candidate_peak >R·f(τ)·P dom_peak

[0143] The threshold condition depends on the dominant peak value P. dom_peak The intensity and adjustment function both depend on the temporal distance τ between the candidate first peak and the dominant peak.

[0144] The UE reports RSTD and / or UE Rx-Tx time difference measurements based on the first peak identified in the CIR power delay distribution within the search window that is higher than a threshold relative to the dominant peak.

[0145] Due to the limited bandwidth available for signal, filter effects, etc., this type of delay-related threshold helps reject side spikes. More specifically, this type of delay-related threshold takes advantage of the fact that side spikes become weaker (in terms of delay) the further they are from the actual channel peak. Therefore, it is possible to avoid using unnecessarily high thresholds that are far from the actual channel peak.

[0146] Figure 5 By showing Figure 4 This is illustrated by a close-up of the strongest peak (which is also the first peak) in the power delay distribution shown. The strongest peak clearly has side peaks like sinc, which can be effectively rejected using a delay-related threshold relative to the peak intensity and the peak position (in terms of delay) relative to the actual channel peak.

[0147] For example, as mentioned above, delay-related threshold conditions can be combined with delay-independent threshold conditions. This can be useful because, to some extent, they serve different purposes. By utilizing a combination of delay-related and simple thresholds, the simple threshold can potentially be set to a higher value because it does not have to reject side peaks. This reduces the risk of missing the detection of actual channel peaks. As further described below, delay-related thresholds can also be combined with thresholds relative to the estimated noise level.

[0148] In another exemplary embodiment, the threshold condition includes a delay-related threshold condition relative to a plurality of peaks. According to this exemplary embodiment, a candidate peak is detected as a peak if (on a linear scale) the following threshold condition is met:

[0149]

[0150] Where, τ k Let p1 represent the time difference between peak k and candidate peaks, where k = 1 represents the dominant peak. Peak search is performed iteratively, where p1 represents the intensity of the dominant peak detected within the search window. If N peaks have been detected, then peak N+1 represents the strongest peak that is earlier than the detected N peaks and meets the following threshold condition:

[0151]

[0152] Where, τ k This represents the time difference between peak k and N+1 candidate peaks. When no more peaks satisfying the iteration criteria can be detected, the last detected peak is used as the "first" peak for the TOA measurement. Figure 6 An example of this embodiment is provided by illustrating the use of a delay-related threshold relative to multiple peaks. Figure 7 An example power delay distribution magnified at the first peak is shown. In this example, there are multiple peaks before the strongest peak, which makes the use of the delay-related threshold relevant to the multiple peaks.

[0153] The parameters transmitted by the signal or determined by the UE according to the rules described herein can be R, f, or any parameters used to derive R, f, or combinations of R·f(...). From the UE's perspective, TOA estimation can then be performed, for example, as follows:

[0154] The UE is configured with several DL PRS via LPP, including parameters that define the search window (e.g., as defined for NR in version 16) and parameters that define the threshold (unless pre-configured).

[0155] The UE is configured via LPP to perform RSTD and / or UE Rx-Tx time difference measurements based on the configured DL PRS.

[0156] For each DL PRS, the UE estimates the CIR within the search window.

[0157] The UE identifies the strongest peak in the CIR power delay distribution within the search window as the dominant peak.

[0158] The UE estimates the intensity P of the dominant peak identified in the CIR power delay distribution within the search window. dom_peak .

[0159] The UE iteratively searches the CIR to find the iteration criterion. The earlier peaks, until no more of these peaks can be identified.

[0160] The UE reports RSTD and / or UE Rx-Tx time difference measurements based on the first peak identified in the CIR power delay distribution within the search window identified through iterative peak search.

[0161] In an alternative embodiment of the delay-related threshold condition relative to multiple peak embodiments, the threshold condition for iterative search can instead be expressed as:

[0162] P candidate_peak_N+1 >R·f(τ) N )·P N

[0163] Depending on the form of the function f, the threshold condition can be mathematically equivalent to the original form.

[0164] In yet another alternative embodiment of the delay-related threshold condition relative to multiple peak embodiments, the threshold condition for iterative search can instead be expressed as:

[0165]

[0166] Applying a delay-related threshold to multiple peaks helps to reject side peaks, not only the strongest peak, but also other peaks.

[0167] It will be understood that embodiments of delay-related threshold conditions relative to multiple peaks can be combined with delay-independent thresholds, for example, as described above. This can be useful because, to some extent, they serve different purposes. As further described below, delay-related thresholds relative to multiple peaks can also be combined with thresholds relative to the estimated noise level.

[0168] According to another exemplary embodiment, threshold conditions can be configured in the case of multiple reference signal configurations. The threshold or parameter can be explicitly signaled or determined by the UE based on description rules for each PRS, each TRP, or each frequency, or it can be applied to more than one PRS, TRP, or frequency within one or more frequency bands. If the same threshold condition or parameter cannot be used for all or multiple PRS configurations, explicit signaling for each threshold and / or set of threshold conditions or parameters will require significant overhead.

[0169] In another example, a reference threshold condition or corresponding parameter for determining R, f, or any parameter used to derive R, f, or a combination of R·f(...) is determined (by signaling, predefined, or defined / calculated based on the described rules) for a reference PRS configuration. Then, if another configuration of the PRS to be received by the UE differs from the reference PRS configuration, the reference threshold condition or corresponding parameter is adapted accordingly. For example, a scaling factor or compensation factor (which can be signaled or predefined) can be applied to accommodate differences (relative to the reference configuration) in one or more of the following:

[0170] The number of PRS symbols, comb configuration, comb size, PRS density in frequency and / or time, PRS bandwidth, number of repetitions within a PRS period, etc. (The more PRS resource elements available, the more accurate the expected measurement will be, and therefore a smaller threshold relative to the strongest peak can be used.)

[0171] PRS search window size (e.g., a smaller search window can trigger a larger threshold)

[0172] The type of environment or radio channel characteristics or propagation conditions or the expected number of candidate peaks (e.g., the more unstable or fading the channel or radio environment, the larger the threshold may be needed, or the more peaks are expected, the smaller the threshold may be used).

[0173] In fact, one or more scaling factors or compensation factors can be used, for example, R = R ref ·k1·k2·..., where R ref The R parameter represents the reference PRS configuration and reference search window configuration or measurement uncertainty. k1 represents the scaling factor used to adapt to differences in PRS density, comb, bandwidth, etc. (This scaling can be defined as a function of these parameters in the table). k2 represents the scaling factor used to adapt to differences in search window configuration or measurement uncertainty. k3 represents the scaling factor used to adapt to the radio environment, etc.

[0174] According to another exemplary embodiment, threshold conditions can be configured when PRS is bound to multiple frequency layers. In NR Release 16, up to four frequency layers can be configured for the UE, where the UE can receive DL PRS. Within a frequency layer, there can be up to 272 PRBs. However, in some scenarios where TOA estimation accuracy requirements are very stringent, it can be beneficial if the UE can receive DL PRS from multiple frequency layers that can be coherently and jointly processed. This results in increased DL PRS bandwidth, which helps meet stringent TOA accuracy requirements. Note that coherent and joint processing of DL PRS from multiple frequency layers is not supported in NR Release 16.

[0175] In one exemplary embodiment, a relative peak threshold condition can be configured for DL ​​PRS from multiple frequency layers that are configured to be coherently and jointly processed at the UE. For example, when the UE receives DL PRS from a TRP in two different frequency layers, the UE can be configured to use a single relative peak threshold condition to identify the first peak in the CIR. From the UE's perspective, this TOA estimation process can be similar to the TOA estimation process given in the delay-independent or delay-dependent embodiments discussed herein, except that the UE can coherently and jointly process DL PRS received from different frequency layers from the same TRP. In some cases, the number of frequency layers used to receive DL PRS can be different for different TRPs. Therefore, in these cases, the number of frequency layers on which DL PRS can be coherently and jointly processed can be different for different TRPs. In other words, different levels of PRS aggregation on frequency layers are possible at different TRPs. Consider an example where TRP1 is configured with DL PRS on four frequency layers, TRP2 with DL PRS on three frequency layers, TRP3 with DL PRS on two frequency layers, and TRP4 with DL PRS on one frequency layer. In this scenario, since different levels of PRS coherent / joint processing are possible at the four TRPS locations, four different relative peak threshold conditions can be configured for the UE. The UE uses the following four different relative peak threshold conditions:

[0176] For TRP1, while the DL PRS from the four frequency layers is being coherently / jointly processed, the first relative peak threshold condition is used by the UE to perform the first peak identification in CIR.

[0177] For TRP2, while the DL PRS from the three frequency layers is being coherently / jointly processed, the second relative peak threshold condition is used by the UE to perform the first peak identification in CIR.

[0178] For TRP3, while the DL PRS from the two frequency layers are being coherently / jointly processed, the third relative peak threshold condition is used by the UE to perform the first peak identification in CIR.

[0179] For TRP4, while the DL PRS from one frequency layer is being processed, the fourth relative peak threshold condition is used by the UE to perform the first peak identification in CIR.

[0180] Note that different relative peak threshold conditions are used in this embodiment because the measurement accuracy improves with coherent / joint processing of DL PRS from more frequency layers. That is, a smaller relative peak threshold can be used when DL PRS from four frequency layers are being processed jointly, compared to when DL PRS from one frequency layer is being processed.

[0181] The solution proposed in this paper repeatedly relies on the "intensity" of the peak value of the CIR within the search window. The peak intensity can be defined in several different ways in various alternative embodiments. Several methods for defining peak intensity are listed below. It will be understood that the solution proposed in this paper is not limited to the techniques listed for determining peak intensity.

[0182] 1. Peak intensity is defined as the peak value in the power delay distribution of the estimated CIR at a given sampling frequency.

[0183] 2. Peak intensity is defined as the peak value in the power delay distribution of the CIR estimated after interpolation between samples.

[0184] 3. Peak intensity is defined after extrapolation.

[0185] 4. Peak intensity is defined as the estimated power delay distribution of the CIR, integraled over a small time interval around the detected peak.

[0186] 5. Peak intensity is defined as the estimated power delay distribution of the CIR, which is obtained by summing or averaging (linear or nonlinear) over a number of samples around the detected peak.

[0187] The power delay distribution of the CIR can be defined as the absolute square of the CIR. Alternatively, the peak intensity can be defined based on the absolute value of the CIR rather than the absolute square of the CIR.

[0188] Note that CIR estimation can be performed in many different ways, for example, in the time domain by a loop related to a known transmitted signal or in the frequency domain by, for example, the following steps:

[0189] FFT to the frequency domain;

[0190] Multiply each subcarrier symbol by the complex conjugate of the corresponding subcarrier symbol of the known transmitted signal;

[0191] If the known transmitted signal does not have a constant amplitude in the frequency domain, then it is also necessary to divide by the amplitude of the known signal for each subcarrier.

[0192] IFFT back to time domain.

[0193] CIR can also be estimated by non-cyclic correlation with known transmitted signals, which gives roughly the same result as cyclic correlation for delays with a small symbol length.

[0194] In some exemplary embodiments, the above threshold condition may also consider, for example, an absolute peak threshold relative to the estimated noise and / or interference level. Therefore, the solution proposed herein will only consider those peaks that also exceed the absolute peak threshold, for example, such as... Figure 5 or Figure 6 As shown in the image.

[0195] More specifically, the relative peak detection threshold can be combined with the absolute threshold A. A candidate peak then needs to exceed both the absolute threshold and satisfy a threshold condition (e.g., exceeding a delay-independent threshold).

[0196] The absolute threshold can also be combined with a delay-related threshold condition. In this case, the requirements for the iterative peak search would be:

[0197]

[0198] as well as

[0199] P candidate_peak_N+1 >A≡10 absolute_threshold_value / 10

[0200] The absolute threshold can be given relative to the estimated noise and interference levels, for example, on a logarithmic scale as absolute_threshold_value = noise_and_interference_gap + estimated noise_and_interference, or on a linear scale as A = R. abs ·σ 2 The "noise_and_interference_gap" can be pre-configured or, for example, signaled to the UE via LPP. The noise_and_interference power can be estimated in several ways. For example, the noise_and_interference power σ can be estimated based on the time-domain cross-correlation (complex vector C) as follows:

[0201]

[0202] Where MADN is the median absolute deviation of the normal distribution, i.e., for the vector x, MADN(x) = median(|x-median(x)|) / 0.675, where the subtraction is performed element-wise.

[0203] The power delay distribution (PDP) of a single symbol is the element-wise absolute square of a vector C. If C contains only noise, the PDP distribution (normalized by σ) is a chi-square distribution with 2 degrees of freedom (DOF). Assuming a PDP of n samples, the probability that all n noisy samples are below the absolute threshold s is given as:

[0204]

[0205] Therefore, the threshold s can be expressed as follows, based on the predefined noise probability P:

[0206]

[0207] Therefore, "noise_and_interference_gap" can be written on a linear scale as:

[0208]

[0209] When using a search window, n should be the number of samples within the search window such that P is the probability that no noise peaks above a threshold are detected within the search window. Note that the relationship with probability P is only valid for Gaussian noise. However, it can also be a good approximation for interfering noise.

[0210] As a signal sent to the UE on a linear or logarithmic scale, R abs The alternative can be the signal transmission probability P. Then the UE will use the above formula to calculate "noise_and_interference_gap".

[0211] The absolute threshold can be combined with the relative threshold in the following alternative manner. The real-valued sampling time set S (representing the interpolated PDP values) is defined as the union of open intervals, where the threshold at samples t = 1, ..., n is satisfied as follows:

[0212]

[0213] Then we find the earliest peak value in S that also meets the relative peak value criterion.

[0214] According to some exemplary embodiments, the absolute peak threshold can be determined based on several PDPs. If we have access to several PDPs, we can perform a peak search on the sum of these PDPs. In this way, we can update old results when new results are available. We can also update the estimated noise scale σ, for example, by stacking all PDP vectors and employing MADN.

[0215] For example, suppose sPDP(t) represents the sum of kPDPs, such as PDP1(t) + ... + PDPk(t). If all PDPs are noise (the underlying cross-correlation is a complex Gaussian distribution with a standard deviation of σ), then sPDP(t) is expressed by Erlang(k, 1 / σ). 2 Given this, the threshold s can be calculated using the following formula:

[0216]

[0217] in,

[0218]

[0219] In this case, s may have to be determined numerically based on a predefined noise probability P.

[0220] According to additional or alternative exemplary embodiments, the absolute peak threshold can be determined based on an approximate probability. If the probability calculation results in a large numerical rounding error, we can use the following approximation:

[0221]

[0222] It is more compact for large P and s. Similarly, for the chi-square case, the following approximation can be used:

[0223]

[0224] Additional exemplary embodiments combine threshold conditions with integrity evaluation. As mentioned herein, numerous techniques exist for configuring CIR peak thresholds or evaluating CIR for accurate TOA estimation. These techniques can vary in complexity and accuracy. Providing reporting support on the selection of this technique and chosen threshold for nodes that have completed TOA estimation (i.e., UEs or network nodes) is an important parameter for other nodes (i.e., network nodes or UEs) to evaluate the quality of TOA estimation. Coupled with this threshold selection by other nodes for the integrity level of the positioning estimation assumptions, it can also be beneficial.

[0225] In an exemplary coupled scenario, threshold conditions can be reported as a localization integrity KPI, which can help assess the quality of TOA estimation.

[0226] In another exemplary coupling scenario, along with the CIR threshold condition signaling, additional data can be transmitted in a specific format indicating the location integrity level of the selected threshold. The format of this data may include, for example:

[0227] Predefined integer values

[0228] Predefined integrity level indicators (e.g., high, medium, low)

[0229] The integrity capability option allows the device to assess the integrity level of the threshold (e.g., a binary value or / or an indication of no).

[0230] According to yet another exemplary embodiment, the UE can be configured to transmit information about all candidate peaks or subsets of candidate peaks within a search window that are detected by the UE and satisfy one or more threshold criteria described herein. These criteria are associated with thresholds that depend on signal level, the relative delay between the strongest peak and candidate peaks, etc. The information about the candidate peaks may include one or more of the following:

[0231] The number of candidate peaks detected;

[0232] The signal level (e.g., power, CIR, etc.) of each candidate peak compared to a specific threshold (e.g., a reference signal level such as the strongest peak, the first detected peak, etc.).

[0233] The relative time of each candidate peak received within the search window compared to a specific threshold (e.g., a reference time such as the time of the strongest peak, the first peak detected, etc.).

[0234] For example, suppose that within the search window, the UE detects a signal level (e.g., CIR, signal strength, signal interference plus noise ratio (SINR), etc.) determined by P. dom_peak The strongest peak value is indicated. The UE further detects that the signal level (e.g., CIR, signal strength, SINR, etc.) is greater than (P). dom_peak -H) has (L-1) additional candidate peaks, where H represents the signal level threshold, and where, as an example, P dom_peak Both H and H are represented on a logarithmic scale. In yet another embodiment, H may also depend on timing information, such as the relative time difference between the reception time of the strongest (dominant) peak and a reference time. In this example, the UE may detect L candidate peaks of the signal received from the signal (e.g., PRS) by a node (e.g., cell, TRP, etc.) measured by the UE.

[0235] In one example, the UE can be configured to send information to the network node about candidate peaks that are detected and meet the threshold condition criteria (as described above). This is based on predefined rules and / or requests received from a network node (e.g., LMF).

[0236] In another example, the UE can be configured to send information about detected candidate peaks that meet the criteria (as described above) to the network node based on predefined rules and / or requests received from a network node (e.g., LMF), depending on the number (M) of detected candidate peaks, where M can be configured or predefined by the network node.

[0237] This is further illustrated with several examples below:

[0238] 1. In one example, the UE is configured to send information only if more than M (e.g., M=2) number of candidate peaks meet the criterion (i.e., at least M candidate peaks are detected to meet the criterion).

[0239] 2. In another example, the UE is configured to send information only if fewer than M (e.g., M=2) number of candidate peaks meet the criterion (i.e., at least M candidate peaks are detected to meet the criterion).

[0240] 3. In yet another example, the UE is configured to send information only if a certain number M (e.g., M=2) of candidate peaks meet the criterion (i.e., only if M candidate peaks are detected to meet the criterion).

[0241] 4. In yet another example, the UE is configured to send information only if any number M of the candidate peaks within a specific range between the M1 and M2 candidate peaks meet a criterion, for example, if the following condition is met:

[0242] (M1≤M≤M2), for example, M1=2 and M2=6.

[0243] In one example, the UE sends information about the candidate peak in any of the above examples, along with measurement results such as RSTD, UE Rx-Tx time difference, and multi-RTT measurement reports.

[0244] In another example, whenever a candidate peak is detected, the UE sends information about the candidate peak in any of the above examples.

[0245] In another example, the UE transmits information about the candidate peak in any of the above examples no more than P times within the positioning session. As a special case, P = 1.

[0246] Network nodes (e.g., LMFs, base stations, etc.) can use information about candidate peaks received from one or more UEs for one or more tasks. For example, a network node can use results from one UE or statistics from multiple UEs (to enhance reliability) for one or more tasks in a specific geographic area or radio environment. Exemplary tasks include, but are not limited to, adapting the values ​​of one or more parameters associated with the positioning process and / or transmitting the received information to another node (e.g., to a BS, to another LMF, etc.). Examples of parameters associated with the positioning process are those used by the UE for candidate peak detection. Examples of such parameters (associated with candidate peak detection) include, but are not limited to, the duration of the search window, a signal threshold, etc. For example, if the number of candidate peaks detected by the UE is higher than a certain threshold, the network node can increase the signal threshold (e.g., H) relative to a certain reference value; otherwise, it can decrease the signal threshold relative to the reference value. In another example, if the number of candidate peaks detected by the UE is higher than a certain threshold, the network node can increase the duration of the search window relative to a certain reference value; otherwise, it can decrease the duration of the search window relative to the reference value. In the future, network nodes can use adapted parameters to configure UEs operating in locations and / or propagation environments similar to those in which information about candidate peaks is obtained by the network node.

[0247] Exemplary embodiments of the solution proposed herein also consider signaling aspects associated with the disclosed threshold conditions. The peak detection threshold or parameter for determining R, f(...), or a combination of Rf(...) can be signaled, for example, in DL PRS auxiliary data, as shown in the example implementation of ASN.1 below. In one example, the range of the threshold is the same as the range of thresholds used for differential PRS-RSRP measurement reporting.

[0248] In this ASN.1 example, the peak detection threshold is located in IENR-DL-PRS-PositioningFrequencyLayer-r16. Alternatively, the peak detection threshold could be located higher in the hierarchical ASN.1 structure, for example, in IENR-DL-PRS-AssistanceData-r16, NR-DL-PRS-AssistanceDataPerFreq-r16, or NR-DL-PRS-AssistanceDataPerTRP-r16, at the cost of reduced flexibility.

[0249]

[0250]

[0251]

[0252] Exemplary embodiments of the solution proposed herein also consider methods for updating threshold conditions. Determining and / or signaling new peak detection threshold conditions, or determining parameters of R, f(...) or a combination of R·f(...), can be triggered by one or more of the following:

[0253] A request, indication, message, or signal measurement indication from the UE requires a new peak detection threshold.

[0254] Send new auxiliary data and / or new measurement configurations using signals.

[0255] The number of candidate peaks (e.g., when it is above the corresponding threshold, the peak detection threshold can be lowered; otherwise, if no or too few peaks are detectable, the peak detection threshold can be increased).

[0256] If the strongest peak value has changed within the time span, or has changed more than another threshold Δ compared to its previous value (e.g., Δ = 0 or Δ > 0 in special cases), then the UE can send an indication to the network node.

[0257] The measured signal is reconfigured (e.g., when the PRS configuration parameters that determine the peak detection threshold or parameter R or f(...) have changed, such as the number of PRS symbols, comb configuration, comb size, PRS density in frequency and / or time, PRS bandwidth, number of repetitions within the PRS period, etc.).

[0258] The PRS search window size (e.g., a smaller search window can trigger a larger threshold) has changed, and

[0259] The environmental type, radio channel characteristics, propagation conditions, or expected number of candidate peaks have changed.

[0260] In another exemplary embodiment, it may not be necessary to send an updated peak detection threshold R or f(...) via signaling. Instead, the UE can autonomously update the peak detection threshold based on predefined rules. For example, a change in PRS BW according to a factor k_BW can trigger an update of the peak detection threshold, where the update depends on k_BW.

[0261] Additional embodiments may consider frequency-nonuniform DL PRS. In NR Release 16, DL PRS is designed to always be frequency-uniform, i.e., counting all DL PRS symbols within a time slot, each subcarrier within the PRB used for DL ​​PRS transmission is used the same number of times. This is achieved by only allowing the DL PRS size in the number of symbols to be a multiple of the comb size, and by combining the relative frequency offset k' in Table 7.4.1.7.3-1 of 38.211, which is captured by CR to 38.211 in R1-2005123, the relevant excerpts of each of which are provided below.

[0262] --------------Starting with an excerpt from CR to 38.211 in R1-2005123----------

[0263] -Time Domain L PRS The size of the downlink PRS resources in ∈{2, 4, 6, 12} is given by the higher-layer parameter dl-PRS-NumSymbols-r16;

[0264] - Comb-like size Given by the higher-level parameter dl-PRS-CombSizeN-r16, the combination Is one of {2,2}, {4,2}, {6,2}, {12,2}, {4,4}, {12,4}, {6,6}, {12,6} and {12,12};

[0265] --------------End of excerpt from CR to 38.211 in R1-2005123----------

[0266] --------------Starting with the table excerpt from CR to 38.211 in R1-2005123----------

[0267] Table 7.4.1.7.3-1: Frequency offset k′ as The function.

[0268]

[0269]

[0270] --------------End of table excerpt from R1-2005123, CR to 38.211----------

[0271] Frequency uniformity ensures the avoidance of side-peaking issues. However, by utilizing a relative peak intensity threshold, side-peaking issues can be controlled, thus removing the restrictions on frequency-uniform DL PRS modes. Certain combinations of restrictions on the comb size and time-domain size of the DL PRS can be removed, and single-symbol DL PRS can also be permitted. This variation can be captured in 38.211, for example, through the following changes (bold for emphasis):

[0272] --------------Modifications to Example 38.211----------

[0273] -Time Domain L PRS The size of the downlink PRS resources in ∈{2, 4, 6, 12} is given by the higher-layer parameter dl-PRS-NumSymbols-r16;

[0274] - Comb-like size Given by the higher-level parameter dl-PRS-CombSizeN-r16,

[0275] --------------End of example modifications for 38.211----------

[0276] In another example, certain combinations of restrictions on the comb size and time domain size of the DL PRS, as specified in NR Release 16, may be removed depending on one or more higher-layer parameters configured to the UE by the network, for example, via LPP. These higher-layer parameters may be explicit configuration parameters for removing the restrictions. In another example, the higher-layer parameter may include the configuration of a peak detection threshold as covered in the embodiments described above. Corresponding modifications to 3GPP TS 38.211 are highlighted in bold below, where higher-layer parameters are denoted as "parameterx":

[0277] --------------Modifications to Example 38.211----------

[0278] If a higher-level parameter, parameterx, is configured,

[0279] -Time Domain L PRS The size of the downlink PRS resources in ∈{2, 4, 6, 12} is given by the higher-layer parameter dl-PRS-NumSymbols-r16;

[0280] - Comb-like size Given by the higher-level parameter dl-PRS-CombSizeN-r16;

[0281] otherwise,

[0282] -Time Domain L PRS The size of the downlink PRS resources in ∈{2, 4, 6, 12} is given by the higher-layer parameter dl-PRS-NumSymbols-r16;

[0283] - Comb-like size Given by the higher-level parameter dl-PRS-CombSizeN-r16, the combination Is one of {2,2}, {4,2}, {6,2}, {12,2}, {4,4}, {12,4}, {6,6}, {12,6} and {12,12};

[0284] --------------End of example modifications for 38.211----------

[0285] In another exemplary embodiment, additional permitted combinations may be added instead of removing the restrictions entirely, for example, as in the example below, where single symbol comb-6 and comb-12 signals are permitted in addition to the already permitted combinations (the change is shown in bold for emphasis):

[0286] --------------Modifications to Example 38.211----------

[0287] -Time Domain L PRS The size of the downlink PRS resources in ∈{2, 4, 6, 12} is given by the higher-layer parameter dl-PRS-NumSymbols-r16;

[0288] - Comb-like size Given by the higher-level parameter dl-PRS-CombSizeN-r16, the combination Is one of {2,2}, {4,2}, {6,2}, {12,2}, {4,4}, {12,4}, {1,6}, {6,6}, {12,6}, {1,12} and {12,12};

[0289] --------------End of example modifications for 38.211----------

[0290] To allow single-symbol DL PRS, signaling changes in 37.355 will also be required, such as the following example modification in 37.355 (based on v16.0.0).

[0291]

[0292]

[0293] This allows for a combination of large comb sizes and short time-domain sizes in DL-PRS. In scenarios where coverage can be achieved with the short time-domain size of DL-PRS (e.g., indoor office or indoor factory scenarios), this significantly reduces positioning overhead. For example, a single-symbol comb-12 signal allows for 12 orthogonal DL-PRS signals using a single OFDM symbol or 144 orthogonal DL-PRS signals utilizing 12 OFDM symbols. Version 16 DL PRS requires at least 12 symbols to allow for 12 orthogonal DL-PRS signals.

[0294] Another alternative example is that the UE can be configured with one of the combinations {2,2}, {4,2}, {6,2}, {12,2}, {4,4}, {12,4}, {6,6}, {12,6}, and {12,12}, but only a subset of symbols in the PRS resource is measured. This can be achieved through an LPP configuration of dl-PRS-NumSymbols-r16 coupled with an additional higher-layer LPP parameter (e.g., dl-PRS-MeasNumSymbols-r16) that signals the symbols to be measured. The additional parameter dl-PRS-MeasNumSymbols-r16 can consist of the number X and means that the Xth symbol in the PRS resource should be considered for measurement. Alternatively, dl-PRS-MeasNumSymbols-r16 can signal the start and end symbols that the UE should measure, or a list of symbols from 1 to dl-PRS-NumSymbols-r16 (e.g., [1, 5, 7] for selecting the first, fifth, and seventh symbols in the resource). This would allow multiple UEs to use the same PRS comb size, but could measure shorter or longer time periods depending on their needs, such as... Figure 8 As shown. Alternatively, the number of consecutive symbols used for a TOA estimate can be limited to allow the UE to perform RX beam scanning within a DL PRS time slot.

[0295] If the UE's ability to process PRS is limited, the UE can accurately report the allowed pairings. Which pair of pairs is supported as part of the capability signaling.

[0296] Figure 9 Another exemplary method 200 for the solution proposed herein, implemented by a wireless device, is shown. The method includes receiving a reference signal from a node within a communication network (box 210). The method also includes receiving an indication of a threshold parameter representing an adjustment to be applied by the wireless device to a set of one or more paths of the reference signal's CIR to generate a path detection threshold for detecting a first path of the CIR within a search window (box 220).

[0297] Figure 10 Another exemplary method 300 for the solution proposed herein, implemented by a network node, is shown. The method includes transmitting a reference signal to a wireless device within a communication network (box 310). The method further includes transmitting an indication of a threshold parameter representing an adjustment to one or more paths of the reference signal's CIR, to be applied by the wireless device to generate a path detection threshold for a first temporally occurring path of the CIR within a search window (box 320).

[0298] Figure 11 A block diagram of a wireless node 400 according to an exemplary embodiment of the solution proposed herein is shown. The wireless node includes methods for performing the TOA methods disclosed herein (e.g., Figure 3 Method 100 Figure 9 Method 200 Figure 1 Method 300, etc., includes one or more processing circuits. As used herein, wireless node 400 includes any node within a wireless communication network, including but not limited to UE, base station (NB, eNB, gNB, etc.) or other network nodes, such as LMF. Exemplary processing circuitry may include separate circuitry for each step, such as a transceiver, CIR processor, identification circuitry, and TOA estimation circuitry. Additional processing circuitry may include parameter and / or threshold determination circuitry. Alternatively, one or more processing circuits may implement two or more steps of the method.

[0299] Note that the apparatus described herein can perform the methods and any other processing described herein by implementing any functional means, modules, units, or circuits. For example, in one embodiment, the apparatus includes various circuits or circuit systems configured to perform the steps shown in the method diagrams. In this regard, the circuits or circuit systems may include circuitry dedicated to performing certain functional processing and / or one or more microprocessors combined with memory. For example, the circuitry may include one or more microprocessors or microcontrollers and other digital hardware, which may include digital signal processors (DSPs), application-specific digital logic, etc. The processing circuitry may be configured to execute program code stored in memory, which may include one or more types of memory, such as read-only memory (ROM), random access memory, cache memory, flash memory devices, optical storage devices, etc. In several embodiments, the program code stored in the memory may include program instructions for executing one or more telecommunications and / or data communication protocols and instructions for executing one or more techniques described herein. In embodiments employing memory, the memory stores program code that, when executed by one or more processors, performs the techniques described herein. Therefore, the various device elements disclosed herein can implement any functional device, module, unit or circuit, and can be embodied in hardware and / or in software (including firmware, resident software, microcode, etc.) executed on a controller or processor (including application-specific integrated circuits (ASICs)).

[0300] This invention can be embodied in a cellular communication system, method, and / or computer program product. Therefore, this invention can be embodied in hardware and / or software (including firmware, resident software, microcode, etc.), including application-specific integrated circuits (ASICs). Furthermore, this invention can take the form of a computer program product on a computer-usable or computer-readable storage medium, in which computer-usable or computer-readable program code is embedded for use by or in conjunction with an instruction execution system. In the context of this document, a computer-usable or computer-readable medium can be any medium that can contain, store, transmit, propagate, or transmit a program used by or associated with an instruction execution system, apparatus, or device. A computer-usable or computer-readable medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, device, or propagation medium. More specific examples (a non-exhaustive list) of computer-readable media will include the following: an electrical connection having one or more wires, a portable computer disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, or portable high-density disk read-only memory (CD-ROM). Note that computer-usable or computer-readable media can even be paper or other suitable media on which the program is printed, because the program can be captured electronically via, for example, optical scanning or paper or other media, and then compiled, interpreted or otherwise processed as needed, and then stored in computer memory.

[0301] The following provides an exemplary implementation of the solution proposed in this paper.

[0302] The first exemplary implementation is a flowchart from the UE's perspective.

[0303] 1) The UE transmits its capabilities to the location server via LPP signals, including the ability to perform peak detection using relative thresholds and the ability to support new DL PRS configurations that are non-uniform in the frequency domain.

[0304] 2) The location server configures the UE via LPP.

[0305] a) It has several PRSs that are non-uniform in the frequency domain, each PRS being transmitted by the TRP.

[0306] b) Auxiliary data, including relative thresholds used for peak search in TOA estimation.

[0307] c) Perform and report RSTD measurements for several TRPs.

[0308] 3) The UE uses the relative threshold in the peak search of the TOA estimate to perform RSTD measurements and reports the measurement results to the location server.

[0309] Another exemplary implementation comes from the perspective of gNB.

[0310] 1) gNB provides DL PRS configuration details to the location server via NRPPa for TRP controlled by gNB.

[0311] 2) The gNB sends several DL PRS from the TRP controlled by the gNB.

[0312] Another exemplary implementation comes from the perspective of a location server.

[0313] 1) The location server receives DL PRS configuration details from several gNBs via NRPPa for the TRP controlled by the gNB.

[0314] 2) The location server has the ability to receive UE data from the UE via LPP, the ability to perform peak detection using thresholds, and the ability to support new DL PRS configurations that are non-uniform in the frequency domain.

[0315] 3) The location server configures the UE via signaling through LPP.

[0316] a) It has several PRSs that are non-uniform in the frequency domain, each PRS being transmitted by the TRP.

[0317] b) Auxiliary data, including relative thresholds used for peak search in TOA estimation.

[0318] c) Perform and report RSTD measurements for several TRPs.

[0319] 4) The location server receives RSTD measurements from the UE via LPP for each TRP and UE antenna panel.

[0320] 5) The location server estimates the UE's location based on RSTD measurements toward several TRPs.

[0321] RTT positioning using CIR peak threshold

[0322] Another exemplary implementation is from the UE's perspective.

[0323] 1) The UE transmits its capabilities to the location server via LPP signals, including the ability to perform peak detection using relative thresholds and the ability to support new DL PRS configurations that are non-uniform in the frequency domain.

[0324] 2) The UE is configured via RRC through its serving gNB with several SRSs.

[0325] 3) The UE is configured via LPP through a location server.

[0326] a) It has several PRSs that are non-uniform in the frequency domain, each PRS being transmitted by the TRP.

[0327] b) Auxiliary data, including relative thresholds used for peak search in TOA estimation.

[0328] c) Perform and report UE Rx-Tx time difference measurement

[0329] 4) The UE uses the relative threshold in the peak search of the TOA estimate to perform UE Rx-Tx time difference measurement and reports the measurement results to the location server.

[0330] 5) The UE sends the configured SRS

[0331] Another exemplary implementation comes from the perspective of the service gNB.

[0332] 1) gNB provides DL PRS configuration details to the location server via NRPPa for TRP controlled by gNB.

[0333] 2) The serving gNB receives a request from the location server via NRPPa to configure several SRSs for the UE, including the proposed SRS configuration.

[0334] 3) The service gNB sends an acknowledgment to the location server via NRPPa signaling that it will configure several SRSs, including SRS configuration details.

[0335] 4) The serving gNB configures the UE via signaling with several SRSs.

[0336] 5) The service gNB receives a request from the location server via NRPPa to perform and report the gNb Rx-Tx time difference measurement.

[0337] 6) The service gNB sends several DL PRS from the TRP controlled by the gNB.

[0338] 7) The serving gNB receives the SRS sent by the UE and performs gNb Rx-Tx time difference measurement.

[0339] 8) The service gNB sends the gNb Rx-Tx time difference measurement to the location server via NRPPa using a signal.

[0340] Another exemplary implementation comes from the perspective of a non-service gNB.

[0341] 1) gNB provides DL PRS configuration details to the location server via NRPPa for TRP controlled by gNB.

[0342] 2) The gNB receives a request from the location server via NRPPa to perform and report gNb Rx-Tx time difference measurements. This request includes SRS configuration details for the measurement.

[0343] 3) The gNB sends several DL PRS from the TRP controlled by the gNB.

[0344] 4) The gNB receives the SRS sent by the UE and performs gNb Rx-Tx time difference measurement.

[0345] 5) gNB sends the gNb Rx-Tx time difference measurement to the location server via NRPPa using a signal.

[0346] Another exemplary implementation comes from the perspective of a location server.

[0347] 1) The location server receives DL PRS configuration details from several gNBs via NRPPa for the TRP controlled by the gNB.

[0348] 2) The location server receives UE capabilities from the UE via LPP, including the ability to perform peak detection using relative thresholds and the ability to support new DL PRS configurations that are non-uniform in the frequency domain.

[0349] 3) The location server sends a request to the UE's serving gNB to configure several SRSs for the UE. This request includes the proposed SRS configurations.

[0350] 4) The location server receives confirmation from the service gNB via NRPPa that it will configure several SRSs, including SRS configuration details.

[0351] 5) The location server configures the UE via signaling through LPP.

[0352] a) It has several PRSs that are non-uniform in the frequency domain, each PRS being transmitted by the TRP.

[0353] b) Auxiliary data, including relative thresholds used for peak search in TOA estimation.

[0354] c) Perform and report UE Rx-Tx time difference measurement

[0355] 6) The location server receives gNb Rx-Tx time difference measurements from several gNBs via NRPPa.

[0356] 7) The location server receives UE Rx-Tx time difference measurements from the UE via LPP.

[0357] 8) The location server estimates the UE's location based on RTT measurements toward several TRPs, utilizing RTT measurements corresponding to different UE antenna panels with different system errors.

[0358] Although the term "TRP" is used in this disclosure, it can be represented by one or more identifiers in the 3GPP specifications. For example, a TRP can be represented by "dl-PRS-Id". The reason is that the UE does not need to know which TRP the DL PRS was sent from; it only needs to know the configuration and ID associated with the DL PRS and perform measurements based on that DL PRS.

[0359] Of course, the invention may be practiced in ways other than those specifically set forth herein without departing from its essential characteristics. The embodiments are to be considered in all respects as illustrative rather than restrictive, and all changes falling within the meaning and equivalents of the appended embodiments are intended to be included therein.

Claims

1. A method (100) for estimating Time of Arrival (TOA) from a wireless node (400) in a wireless communication network, the method (100) comprising: Receive one or more reference signals (110) from one or more remote wireless nodes; In response to one or more received reference signals, estimate the (120) channel impulse response CIR; The first peak of the CIR within the search window that meets the threshold condition in time is identified (130) as the TOA peak, wherein the threshold condition is defined in response to the intensity of the dominant peak of the CIR within the search window; and Based on the TOA peak estimate (140), the TOA, Wherein, the threshold condition is whether the candidate peak of CIR within the search window exceeds a peak threshold defined in response to the intensity of the dominant peak, and The peak threshold is defined in response to the intensity of the dominant peak and an adjustment function, the adjustment function being a function of the time difference between the dominant peak time and the candidate peak time.

2. The method (100) according to claim 1, wherein, The peak threshold is defined in response to the intensity and adjustment value of the dominant peak.

3. The method (100) according to claim 2, wherein, The peak threshold is defined as reducing the intensity of the dominant peak value of the adjusted value.

4. The method (100) according to claim 1, wherein, The adjustment function also includes a function that modifies the time difference between the dominant peak time and the candidate peak time of the adjustment value.

5. The method (100) according to claim 1, wherein, The adjustment function includes a function that is inversely proportional to the square of the time difference.

6. The method (100) according to claim 1, wherein: The peak threshold includes: a candidate peak threshold for each candidate peak in a search window containing the dominant peak, wherein each candidate peak threshold is defined in response to an adjustment function and the intensity of the corresponding candidate peak and all previous peaks in the search window, and a corresponding adjustment function for each of the previous peaks, the adjustment function including a function of the time difference between the candidate peak and the corresponding previous peak; and The identification (130) of the first peak in time within the search window that meets the threshold condition as the TOA peak includes: Iteratively compare the intensity of each candidate peak with a corresponding candidate peak threshold condition until no earlier candidate peak exceeds the corresponding candidate peak threshold; and The last candidate peak that exceeds the corresponding candidate peak threshold is identified as the TOA peak.

7. The method (100) of claim 2, further comprising receiving the adjustment value from at least one of the one or more remote wireless nodes or from another node within the wireless communication network.

8. The method (100) of claim 2, further comprising determining the adjustment value in response to one or more rules pre-configured for the wireless node (400).

9. The method (100) according to claim 8, wherein, The one or more rules include one or more rules pre-configured for each positioning reference signal, pre-configured for each remote wireless node, and / or pre-configured for each frequency.

10. The method (100) according to claim 2, wherein, The adjustment value is determined based on a reference adjustment value and one or more compensation factors.

11. The method (100) according to claim 10, wherein, The one or more compensation factors are associated with a reference signal configuration for a reference signal, wherein the CIR is estimated for the reference signal.

12. The method (100) of claim 10, further comprising using the one or more compensation factors to adjust the reference adjustment value to determine the adjustment value.

13. The method (100) of claim 12, further comprising receiving the reference adjustment value from at least one of the one or more remote wireless nodes or from another node within the wireless communication network.

14. The method (100) of claim 12, further comprising receiving one or more threshold adjustments from at least one of the one or more remote wireless nodes or from another node within the wireless communication network.

15. The method (100) according to claim 1, wherein, Defining the threshold conditions includes defining the threshold conditions in response to one or more rules pre-configured for the wireless node.

16. The method (100) according to claim 15, wherein, The one or more rules include one or more rules pre-configured for each positioning reference signal, pre-configured for each remote wireless node, and / or pre-configured for each frequency.

17. The method (100) according to claim 1, wherein, The peak threshold is calculated in response to at least one of the following and the intensity of the dominant peak: The size of the search window; The number of the one or more reference signals received from the one or more remote wireless nodes; The comb configuration of each of the one or more received reference signals; Reference signal density at frequency; Temporal reference signal density; Reference signal bandwidth; The number of times the reference signal repeats within the reference signal period; as well as One or more characteristics of a wireless channel that transmits the one or more reference signals to the wireless node (400).

18. The method (100) of claim 1, further comprising coherently and jointly processing reference signals received via multiple frequency layers, wherein, Estimating the CIR involves estimating the CIR within the search window in response to a coherently and jointly processed reference signal.

19. The method (100) according to claim 18, wherein: Coherently and jointly processing reference signals received via multiple frequency layers includes: first coherently and jointly processing reference signals received from a first remote wireless node via a first plurality of frequency layers, and second coherently and jointly processing reference signals received from a second remote wireless node via a second plurality of frequency layers. Estimating (120) the CIR includes: estimating a first CIR within the search window in response to a first coherently and jointly processed reference signal, and estimating a second CIR within the search window in response to a second coherently and jointly processed reference signal; and Defining the threshold conditions includes: defining a first threshold condition in response to the intensity of the dominant peak of the first CIR within the search window, and defining a second threshold condition in response to the intensity of the dominant peak of the second CIR within the search window.

20. The method (100) according to claim 1, wherein, The intensity of any peak in the search window includes one of the following: The peak value in the power delay distribution of the CIR at a given sampling frequency; The peak value in the power delay distribution of the CIR after interpolation between samples; The power delay distribution of the CIR integrated over the time period around the corresponding peak; The power delay distribution of the CIR summed over several samples around the corresponding peak; and The power delay distribution of the CIR is averaged over several samples around the corresponding peak.

21. The method (100) according to claim 20, wherein, The power delay distribution includes the absolute square of the CIR.

22. The method (100) according to claim 20, wherein, The power delay distribution includes the absolute value of the CIR.

23. The method (100) according to claim 1, wherein, At least one of the one or more remote wireless nodes includes a network node, and receiving the one or more reference signals includes receiving one or more downlink reference signals from the network node.

24. The method (100) according to claim 1, wherein, At least one of the one or more remote wireless nodes includes a user equipment (UE), and receiving the one or more reference signals includes receiving one or more uplink reference signals from the UE.

25. A wireless node (400) in a wireless communication system, configured to estimate the time of arrival (TOA) of one or more reference signals received from one or more remote wireless nodes, the wireless node (400) including one or more processing circuits (410) configured to perform the method (100) according to any one of claims 1 to 24.

26. A computer program product for controlling a wireless node (400), the computer program product comprising software instructions that, when executed on at least one processing circuit (410) in the wireless node (400), cause the wireless node (400) to perform the method (100) according to any one of claims 1 to 24.

27. A computer-readable medium comprising a computer program product according to claim 26.

28. The computer-readable medium of claim 27, wherein, The computer-readable medium includes non-transitory computer-readable media.

29. A method (200) performed by a wireless device (400) in a communication network, the method (200) comprising: Receive (210) reference signals from nodes within the communication network; as well as Receive (220) an indication of a threshold parameter, the threshold parameter representing the following adjustment: the adjustment to be applied by the wireless device to a set of one or more paths of the channel impulse response (CIR) of the reference signal to generate a path detection threshold for detecting a first temporal path of the CIR within a search window. The path detection threshold is defined in response to the intensity of the dominant peak of the CIR within the search window and an adjustment function, wherein the adjustment function includes a function of the time difference between the dominant peak time and the candidate peak time.

30. The method (200) according to claim 29, further comprising the step of: The arrival time of the reference signal is calculated using the threshold parameter based on the first path in time that exceeds the path detection threshold within the CIR in the search window.

31. The method (200) according to claim 29, wherein, The indication of the threshold parameter is received as part of the auxiliary data of the reference signal.

32. The method (200) according to claim 31, wherein, The auxiliary data also includes the duration of the search window.

33. The method (200) of claim 29 further includes receiving an indication of a threshold parameter, the threshold parameter representing an adjustment to be applied to the strongest path of the CIR response within the search window.

34. A method (300) performed by a network node (400) in a communication network, the method (300) comprising: Send a (310) reference signal to a wireless device within the communication network; as well as Sending an instruction (320) for a threshold parameter, the threshold parameter representing an adjustment to be applied by the wireless device to a set of one or more paths of the channel impulse response (CIR) of the reference signal to generate a path detection threshold for a first temporal path of the CIR within a search window. The path detection threshold is defined in response to the intensity of the dominant peak of the CIR within the search window and an adjustment function, wherein the adjustment function includes a function of the time difference between the dominant peak time and the candidate peak time.

35. The method (300) according to claim 34, wherein, The indication of the threshold parameter is sent as part of the auxiliary data of the reference signal.

36. The method (300) according to claim 35, wherein, The auxiliary data also includes the duration of the search window.

37. The method (300) according to any one of claims 34 to 36, further comprising sending an indication of a threshold parameter, the threshold parameter representing an adjustment to be applied to the strongest path of the CIR response within the search window.

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