Delay estimation method, device, equipment and storage medium

Abstract

The present application discloses a delay estimation method, device, equipment and storage medium, and relates to the field of mobile communication technology. The specific implementation scheme is: determine the channel estimation value based on the received reference signal; generate a matrix according to the preset maximum distance from the user to the base station and the delay quantization interval; generate a signal spectrum space according to the channel estimation value and the matrix; obtain the delay estimation value between the user and the base station based on the signal spectrum space and the preset threshold value. As a result, the accuracy of the delay estimation between the user's communication device and the base station is improved, and further, technical support is provided for compensating for the delay to improve the communication quality.

Description

Technical Field

[0001] The present application relates to the field of mobile communication technology, and in particular to a delay estimation method, device, equipment and storage medium. Background Art

[0002] In a cellular communication system, there is a certain distance between a user's communication device and a base station, which causes the signal transmitted by the communication device to arrive later than the expected time of the base station, that is, there is a time delay.

[0003] In the related art, the accuracy of communication delay estimation is not high. If the delay of the delayed signal is not accurately estimated, the quality of channel estimation will be affected, which will in turn affect the multi-user pairing performance, downlink shaping gain performance, uplink reception performance and related measurement quantities, thereby causing losses in uplink and downlink throughput. In addition, uplink channel synchronization is also closely related to the accuracy of delay estimation. If the delay estimation error is large, it will cause the uplink channel to lose synchronization, thereby generating inter-symbol interference, seriously affecting system performance, and even interrupting the communication of the communication equipment. Summary of the invention

[0004] The present disclosure provides a delay estimation method, apparatus, device and storage medium for solving the problem that the delay estimation error between a user's communication device and a base station is large, which affects the communication quality.

[0005] According to one aspect of the present disclosure, a delay estimation method is provided, the method comprising: determining a channel estimation value based on a received reference signal; generating a matrix according to a preset maximum distance from a user to a base station and a delay quantization interval; generating a signal spectrum space according to the channel estimation value and the matrix; and obtaining a delay estimation value between the user and the base station based on the signal spectrum space and a preset threshold value.

[0006] Optionally, determining a channel estimation value based on a received reference signal includes:

[0007] The base station receives an uplink reference signal sent by a user, and determines a channel estimation value according to the uplink reference signal;

[0008] Alternatively, the user receives a downlink reference signal sent by the base station, and determines a channel estimation value according to the downlink reference signal.

[0009] Optionally, a channel estimation value is determined based on a received reference signal according to a first formula, wherein the first formula includes:

[0010] h(i)=r(i)*conj(s(i)),i=1,2,...,N SC

[0011] Where i is the subcarrier index, r is the received reference signal sequence, s is the local reference signal sequence, h is the estimated channel, N SC Indicates the number of subcarriers.

[0012] Optionally, generating a matrix according to a preset maximum distance from a user to a base station and a delay quantization interval includes:

[0013] The maximum distance from the user to the base station and the delay quantization interval are calculated according to the second formula to generate the maximum number of columns of the matrix, wherein the second formula includes:

[0014] M max =floor(d max / c*10 9 / step) or,

[0015] M max =ceil(d max / c*10 9 / step) or,

[0016] M max =round(d max / c*10 9 / step),

[0017] Where c = 3 × 10 8 Meters / second, floor means round down, ceil means round up, round means round up, d max is a scene parameter, step represents the delay quantization interval;

[0018] Get the minimum number of columns of the preset matrix;

[0019] Calculating a target number of columns of the matrix according to the maximum number of columns and the minimum number of columns, and using the number of subcarriers as a target number of rows of the matrix;

[0020] The subcarrier spacing and the delay quantization spacing are calculated according to a third formula to generate a matrix matching the target number of rows and the target number of columns, wherein the third formula includes:

[0021]

[0022] Where k = 0, 1, ..., N SC -1; Δf is the subcarrier spacing, the unit is Hz; m is an integer, the value range is M min ≤m≤M max , where M min The default minimum number of columns.

[0023] Optionally, a signal spectrum space is generated for the channel estimation value and the matrix according to a fourth formula, wherein the fourth formula includes:

[0024]

[0025] Among them, m=0,1,2,......,M-1.

[0026] Optionally, also include:

[0027] The M values ​​in the signal spectrum space are normalized.

[0028] Optionally, also include:

[0029] Obtaining a signal minimum value from the signal spectrum space;

[0030] Add N minimum values ​​of the signal before each signal in the signal spectrum space.

[0031] Optionally, the acquiring the estimated value of the time delay between the user and the base station based on the signal spectrum space and a preset threshold value includes:

[0032] Acquire, from the signal spectrum space according to a preset function, an index corresponding to the first peak whose signal value exceeds the threshold value;

[0033] The index is calculated according to a preset fifth formula to obtain an estimated value of the delay between the user and the base station, wherein the fifth formula includes:

[0034] If the index starts numbering from 1, then:

[0035] τ=(index-N+M min -1)*10 -9 *step

[0036] If the index starts numbering from 0, then:

[0037] τ=(index-N+M min )*10 -9 *step,

[0038] Here, step represents the delay quantization interval.

[0039] Optionally, also include:

[0040] Acquire multiple delay estimation values ​​between the user and multiple base stations;

[0041] The spatial position of the user is acquired according to the multiple delay estimation values.

[0042] According to another aspect of the present disclosure, a terminal device is provided, including a memory, a transceiver, and a processor: the memory is used to store a computer program; the transceiver is used to send and receive data under the control of the processor; the processor is used to read the computer program in the memory and perform the following operations: determine a channel estimation value based on a received reference signal; generate a matrix according to a preset maximum distance from the user to the base station and a delay quantization interval; generate a signal spectrum space according to the channel estimation value and the matrix; obtain a delay estimation value between the user and the base station based on the signal spectrum space and a preset threshold value.

[0043] Optionally, determining a channel estimation value based on a received reference signal includes:

[0044] The base station receives an uplink reference signal sent by a user, and determines a channel estimation value according to the uplink reference signal;

[0045] Alternatively, the user receives a downlink reference signal sent by the base station, and determines a channel estimation value according to the downlink reference signal.

[0046] Optionally, a channel estimation value is determined based on a received reference signal according to a first formula, wherein the first formula includes:

[0047] h(i)=r(i)*conj(s(i)),i=1,2,...,N SC

[0048] Where i is the subcarrier index, r is the received reference signal sequence, s is the local reference signal sequence, h is the estimated channel, N SC Indicates the number of subcarriers.

[0049] Optionally, generating a matrix according to a preset maximum distance from a user to a base station and a delay quantization interval includes:

[0050] The maximum distance from the user to the base station and the delay quantization interval are calculated according to the second formula to generate the maximum number of columns of the matrix, wherein the second formula includes:

[0051] M max =floor(d max / c*10 9 / step) or,

[0052] M max =ceil(d max / c*10 9 / step) or,

[0053] M max =round(d max / c*10 9 / step),

[0054] Where c = 3 × 10 8 Meters / second, floor means round down, ceil means round up, round means round up, d max is a scene parameter, step represents the delay quantization interval;

[0055] Get the minimum number of columns of the preset matrix;

[0056] Calculating a target number of columns of the matrix according to the maximum number of columns and the minimum number of columns, and using the number of subcarriers as a target number of rows of the matrix;

[0057] The subcarrier spacing and the delay quantization spacing are calculated according to a third formula to generate a matrix matching the target number of rows and the target number of columns, wherein the third formula includes:

[0058]

[0059] Where k = 0, 1, ..., N SC -1; Δf is the subcarrier spacing, the unit is Hz; m is an integer, the value range is M min ≤m≤M max , where M min The default minimum number of columns.

[0060] Optionally, a signal spectrum space is generated for the channel estimation value and the matrix according to a fourth formula, wherein the fourth formula includes:

[0061]

[0062] Among them, m=0,1,2,......,M-1.

[0063] Optionally, also include:

[0064] The M values ​​in the signal spectrum space are normalized.

[0065] Optionally, the method further includes: obtaining a signal minimum value from the signal spectrum space;

[0066] Add N minimum values ​​of the signal before each signal in the signal spectrum space.

[0067] Optionally, the acquiring the estimated value of the time delay between the user and the base station based on the signal spectrum space and a preset threshold value includes:

[0068] Acquire, from the signal spectrum space according to a preset function, an index corresponding to the first peak whose signal value exceeds the threshold value;

[0069] The index is calculated according to a preset fifth formula to obtain an estimated value of the delay between the user and the base station, wherein the fifth formula includes:

[0070] If the index starts numbering from 1, then:

[0071] τ=(index-N+M min -1)*10 -9 *step

[0072] If the index starts numbering from 0, then:

[0073] τ=(index-N+M min )*10 -9 *step,

[0074] Here, step represents the delay quantization interval.

[0075] Optionally, also include:

[0076] Acquire multiple delay estimation values ​​between the user and multiple base stations;

[0077] The spatial position of the user is acquired according to the multiple delay estimation values.

[0078] According to another aspect of the present disclosure, a delay estimation device is provided, the device comprising:

[0079] A determination module, configured to determine a channel estimation value based on a received reference signal;

[0080] A first generating module, used to generate a matrix according to a preset maximum distance from a user to a base station and a delay quantization interval;

[0081] A second generating module, used for generating a signal spectrum space according to the channel estimation value and the matrix;

[0082] An acquisition module is used to acquire an estimated value of the time delay between the user and the base station based on the signal spectrum space and a preset threshold value.

[0083] According to another aspect of the present disclosure, a processor-readable storage medium is provided, wherein the processor-readable storage medium stores a computer program, and the computer program is used to enable the processor to execute the delay estimation method described in the above embodiment.

[0084] The delay estimation method, apparatus, device, and storage medium proposed in this application have at least the following additional technical effects:

[0085] Based on the received reference signal, the channel estimation value is determined, and the matrix is ​​generated according to the preset maximum distance from the user to the base station and the delay quantization interval. Then, the signal spectrum space is generated according to the channel estimation value and the matrix. Finally, the delay estimation value between the user and the base station is obtained based on the signal spectrum space and the preset threshold value. In this way, the accuracy of the delay estimation between the user's communication device and the base station is improved, and further, technical support is provided for compensating for the delay and improving the communication quality.

[0086] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present disclosure, nor is it intended to limit the scope of the present disclosure. Other features of the present disclosure will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0087] The accompanying drawings are used to better understand the present solution and do not constitute a limitation of the present application.

[0088] Figure 1 is a flowchart of a delay estimation method according to an embodiment of the present application;

[0089] Figure 2 is a schematic diagram of a CDF error curve according to an embodiment of the present application;

[0090] Figure 3 is a flowchart of a delay estimation method according to another embodiment of the present application;

[0091] Figure 4 is a flowchart of a delay estimation method according to another embodiment of the present application;

[0092] Figure 5 is a schematic diagram of an application scenario of a delay estimation method according to an embodiment of the present application;

[0093] Figure 6 is a block diagram of a terminal device used to implement the method for delay estimation in an embodiment of the present application;

[0094] Figure 7 It is a block diagram of a device that can implement the delay estimation of the embodiment of the present application. DETAILED DESCRIPTION

[0095] In the embodiments of the present invention, the term "and / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent three situations: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the associated objects before and after are in an "or" relationship.

[0096] In the embodiments of the present application, the term "plurality" refers to two or more than two, and other quantifiers are similar.

[0097] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0098] The following describes the delay estimation method, apparatus, device and storage medium of the embodiment of the present application with reference to the accompanying drawings, wherein the execution subject of the delay estimation method of the embodiment of the present application may be a network device, which may be a network device such as a base station, or a terminal device of a user end, wherein the terminal device involved in the embodiment of the present application may be a device that provides voice and / or data connectivity to a user, a handheld device with a wireless connection function, or other processing devices connected to a wireless modem, etc. In different systems, the name of the terminal device may also be different. For example, in a 5G system, the terminal device may be called a user equipment (UE). The wireless terminal device may communicate with one or more core networks (CN) via a radio access network (RAN). The wireless terminal device may be a mobile terminal device, such as a mobile phone (or a "cellular" phone) and a computer with a mobile terminal device, for example, a portable, pocket-sized, handheld, computer-built-in or vehicle-mounted mobile device, which exchanges language and / or data with the radio access network. For example, Personal Communication Service (PCS) phones, cordless phones, Session Initiated Protocol (SIP) phones, Wireless Local Loop (WLL) stations, Personal Digital Assistants (PDA) and other devices. Wireless terminal devices may also be referred to as systems, subscriber units, subscriber stations, mobile stations, mobile stations, remote stations, access points, remote terminal devices, access terminal devices, user terminal devices, user agents, and user devices, which are not limited in the embodiments of the present application.

[0099] Specifically, Figure 1 is a flowchart of a delay estimation method according to an embodiment of the present application. Figure 1 As shown, the method includes:

[0100] Step 101: Determine a channel estimation value based on a received reference signal.

[0101] The reference signal may be any test signal agreed upon for estimating the delay, for example, a heartbeat signal, etc. In addition, the channel estimation value may be understood as a channel for which the delay is to be estimated.

[0102] In this embodiment, the delay of the channel can obviously be reflected by the transmission status of the signal on the channel. Therefore, the corresponding channel estimation value can be determined according to the received reference signal.

[0103] Step 102: Generate a matrix according to a preset maximum distance from the user to the base station and a delay quantization interval.

[0104] It should be noted here that the preset maximum distance from the user to the base station (in meters, etc.) should be the maximum distance from the user to the base station calibrated according to experimental data when the user's communication equipment is under the distance accuracy required by the positioning error. In addition, the delay quantization interval is the time interval of the user quantization delay calibrated according to the delay data. The quantization unit is nanoseconds and is represented by "step" in subsequent embodiments.

[0105] In this embodiment, in order to facilitate subsequent calculations, a matrix is ​​generated based on the preset maximum distance from the user to the base station and the delay quantization interval, wherein the method of generating the matrix of the maximum distance from the user to the base station and the delay quantization interval can be any method of splitting the multiple values ​​contained in the maximum distance and the delay quantization interval into matrix elements, which will be described in detail in subsequent embodiments and will not be repeated here.

[0106] Step 103: Generate a signal spectrum space according to the channel estimation value and the matrix.

[0107] In this embodiment, a signal spectrum space is generated according to the channel estimation value and the matrix, that is, the delay estimation value between the user and the base station is calculated in the signal spectrum space with richer dimensions. In some possible embodiments, the channel estimation value and the matrix can be directly conjugate multiplied to obtain the signal spectrum space p new .

[0108] Step 104: Obtain an estimated value of the time delay between the user and the base station based on the signal spectrum space and a preset threshold value.

[0109] In this embodiment, the peak closest to the actual delay of the user is searched in the signal spectrum space. The delay value corresponding to this peak is the user delay estimation value. The method of finding the peak closest to the actual delay of the user introduces a preset threshold value to filter the interference information. The preset threshold value is calibrated according to the delay data and is related to the specific communication environment, etc.

[0110] In one embodiment of the present application, the peak index closest to the actual user delay is found in the signal spectrum space, and the corresponding index can be calculated by the following formula (1), where thr is the threshold value for filtering interference, and the function findpeak represents the search for the signal spectrum space p new The index corresponding to the first peak whose size exceeds thr in the spectrum, where the first peak is counted from the origin to the right with the horizontal axis of the signal space spectrum as the ray and the starting point as the origin. The index can be understood as the unique information of any identification peak, for example, it can be a digital number, etc.:

[0111] index=findpeak(p new ,thr) Formula (1)

[0112] Further, a corresponding delay estimation value is determined according to the index corresponding to the first peak, wherein the delay estimation value is represented by τ in subsequent embodiments, and the unit is seconds.

[0113] Therefore, the delay estimation method in the embodiment of the present application adopts the time domain correlation method, and the time length from the maximum correlation peak to the starting point is the delay estimation value, which greatly improves the accuracy of the delay estimation value. The effect of the delay estimation in the embodiment of the present application is explained below in combination with a specific scenario. In this scenario, an experiment is conducted based on the 3GPP (3rd Generation Partnership Project) channel model TDL_D (Terminal Display Language D, D channel of terminal display language).

[0114] Under different SRS (Sounding Reference Signal) bandwidths (256PRB (Physical Resource Block) and 64PRB) and different SNRs (5dB, -5dB), the CDF (cumulative distribution function) curves of the delay estimation error of the present application and the traditional solution are as follows: Figure 2 As shown, since the delay value is very small, in order to more clearly see the difference in estimation accuracy, the delay estimation error (absolute value) is multiplied by the speed of light in the CDF curve to convert it into a distance estimation error, so the horizontal axis unit is meter.

[0115] Reference Figure 2 , the horizontal axis is the delay estimation error, which is converted into the distance error, and the vertical axis is the CDF. Figure 2 , the delay estimation error when CDF = 90% is summarized in Table 1:

[0116] Table 1

[0117]

[0118]

[0119] It can be seen from the above table that the delay estimation error of the present application is much smaller than that of the traditional solution. The estimation error under different SRS bandwidths and different SNRs is less than 0.3, which can meet the requirements of high-precision positioning.

[0120] In addition, the delay estimation error of the solution of the present application is less affected by the SRS bandwidth, and as the SRS bandwidth decreases, the delay estimation error increases slightly; the delay estimation error of the traditional solution is greatly affected by the SRS bandwidth, and as the SRS bandwidth decreases, the delay estimation error increases exponentially.

[0121] In summary, the delay estimation method of the embodiment of the present application determines the channel estimation value based on the received reference signal, generates a matrix based on the preset maximum distance from the user to the base station and the delay quantization interval, and then generates a signal spectrum space based on the channel estimation value and the matrix, and finally, obtains the delay estimation value between the user and the base station based on the signal spectrum space and the preset threshold value. As a result, the accuracy of the delay estimation between the user's communication device and the base station is improved, and further, technical support is provided for compensating for delay to improve communication quality.

[0122] In the actual implementation process, as described in the above embodiment, the transmission status of the reference signal in the channel can be summarized to obtain a channel estimation value, and the parameters representing the transmission status of the reference signal may be different in different scenarios. Therefore, in different application scenarios, the channel estimation value is determined based on the received reference signal in different ways, and the examples are described as follows:

[0123] In this example, the manner of determining the channel estimation value based on the received reference signal according to the first formula is different. As a possible implementation manner, the channel estimation value is determined based on the received reference signal according to the first formula, wherein the first formula may be as shown in the following formula (2):

[0124] h(i)=r(i)*conj(s(i)),i=1,2,...,N SC Formula (2)

[0125] In formula (2), i is the subcarrier index, r is the received reference signal sequence, s is the local reference signal sequence, h is the estimated channel, and N SC Represents the number of subcarriers, where each channel contains multiple subcarriers. The subcarriers are used to modulate the reference signal. The subcarrier index i can be any parameter that can identify the uniqueness of the subcarrier, such as the digital number of the subcarrier.

[0126] The above-mentioned reference signal can be received in any manner, for example, the base station receives an uplink reference signal sent by a user, and determines a channel estimation value according to the uplink reference signal.

[0127] It can be understood that the base station receives an uplink reference signal sent by the user's communication device. The uplink reference signal can be any signal used to detect channel delay. Further, the channel estimation value can be determined according to the uplink reference signal.

[0128] In this example, the user may also receive a downlink reference signal sent by the base station and determine a channel estimation value according to the downlink reference signal.

[0129] In this embodiment, the user's communication device receives a downlink reference signal sent by a base station. The downlink reference signal may be any signal used to detect channel delay. Further, a channel estimation value may be determined according to the downlink reference signal.

[0130] Similarly, in different application scenarios, the manner of generating a matrix according to the preset maximum distance from the user to the base station and the delay quantization interval is also different. To facilitate understanding by those skilled in the art, in this embodiment, in combination with the above example, an example is further provided to illustrate how to generate a matrix according to the preset maximum distance from the user to the base station and the delay quantization interval:

[0131] In this example, if Figure 3 As shown, a matrix is ​​generated according to the preset maximum distance from the user to the base station and the delay quantization interval, including:

[0132] Step 301: Calculate the maximum distance from the user to the base station and the delay quantization interval according to the second formula to generate the maximum number of columns of the matrix.

[0133] In some possible embodiments, the second formula is formula (3), where formula (3) is:

[0134] M max =floor(d max / c*10 9 / step) formula (3)

[0135] Among them, M max The number of columns of the matrix is ​​the largest, c = 3 × 108 m / s, floor means round down, step means delay quantization interval, d max is the scene parameter.

[0136] In some other possible embodiments, the second formula is formula (4), where formula (4) is:

[0137] M max =ceil(d max / c*10 9 / step) formula (4)

[0138] Among them, M max The number of columns of the matrix is ​​the largest, c = 3 × 10 8 m / s, step indicates the delay quantization interval, ceil indicates rounding up, d max is the scene parameter.

[0139] In some other possible embodiments, the second formula is formula (5), where formula (5) is:

[0140] M max =round(d max / c*10 9 / step) formula (5)

[0141] Among them, M max The number of columns of the matrix is ​​the largest, c = 3 × 10 8 Meters / second, step represents the delay quantization interval, d max It is the scene parameter, and round means rounding.

[0142] Step 302: Obtain a preset minimum number of columns of the matrix.

[0143] Among them, the preset minimum number of columns of the matrix is ​​M min It can be any integer calibrated according to experimental data, for example, it can be a positive integer or a negative integer.

[0144] Step 303: Calculate the target number of columns of the matrix according to the maximum number of columns and the minimum number of columns, and use the number of subcarriers as the target number of rows of the matrix.

[0145] In this embodiment, the target number of columns of the matrix is ​​calculated according to the maximum number of columns and the minimum number of columns, for example, according to formula (6), where formula (6) is as follows, where M is the target number of columns:

[0146] M=M max -M min +1Formula(6)

[0147] Step 304: Calculate the subcarrier spacing and the delay quantization spacing according to the third formula to generate a matrix matching the target number of rows and the target number of columns.

[0148] In some possible embodiments, the third formula is shown in the following formula (7), where formula (7) is:

[0149]

[0150] In formula (7), k = 0, 1, ..., N SC -1, N SC Indicates the number of subcarriers, Δf is the subcarrier spacing, the unit is Hz; m is an integer, the value range is M min ≤m≤M max , where M min The preset minimum number of columns, matrix V, dimension N SC ×M.

[0151] Furthermore, in different application scenarios, the manners of generating the signal spectrum space according to the channel estimation value and the matrix are different. To facilitate the understanding of those skilled in the art, the following describes how to generate the signal spectrum space according to the estimation value and the matrix based on the above example:

[0152] In this example, a signal spectrum space is generated for the channel estimation value and the matrix according to a fourth formula, wherein the fourth formula is as shown in the following formula (8), wherein in formula (8), m=0, 1, 2, ..., M-1:

[0153]

[0154] In order to facilitate the estimation of the delay, in one embodiment of the present application, the M values ​​in the signal spectrum space may be normalized, wherein the normalization formula may be as shown in formula (9), wherein in formula (9), the p on the left side new is the normalized value, and p on the right side of the formula new is the original value, max(p new ) is the maximum value of the signal in the signal spectrum space:

[0155]

[0156] In one embodiment of the present application, in order to improve the stability of delay estimation, the minimum value of the signal can be obtained from the signal spectrum space, and N minimum values ​​of the signal are added before each signal in the signal spectrum space, where N ≥ 1. Thus, the number of signals in the signal spectrum space becomes N + M. For example, the minimum value of the signal P is obtained in the signal spectrum space. min , p min =min{p new}, then the signal spectrum space is updated to: p new =[p min,1 p min,2 ,...,p min,N p new ].

[0157] In this embodiment, obtaining a delay estimation value between a user and a base station based on a signal spectrum space and a preset threshold value includes:

[0158] After obtaining the index corresponding to the first peak whose signal value exceeds the threshold value from the signal spectrum space according to the preset function, the index can be calculated according to the preset fifth formula to obtain the estimated value of the delay between the user and the base station, wherein the preset fifth formula can refer to formulas (10) and (11), wherein in formulas (10) and (11), step represents the delay quantization interval, and index is p new The index of the first peak whose size exceeds the preset threshold:

[0159] If the index starts numbering from 1, then:

[0160] τ=(index-N+M min -1)*10 -9 *step formula(10)

[0161] If the index starts numbering from 0, then:

[0162] τ=(index-N+M min )*10 -9 *step formula(11)

[0163] In summary, the delay estimation method of the embodiment of the present application can flexibly select the method of calculating the parameters required for the delay estimation value according to the scenario requirements, thereby improving the practicality of the delay estimation.

[0164] Based on the above embodiments, the delay estimation of the present application can improve the accuracy of the delay estimation value, thereby providing technical support for accurate positioning.

[0165] In one embodiment of the present application, Figure 4 As shown, the method also includes:

[0166] Step 401: Acquire multiple delay estimation values ​​between a user and multiple base stations.

[0167] The calculation method of the estimated value of the time delay between the user and each base station may refer to the above embodiment and will not be described in detail here.

[0168] Step 402: Acquire the spatial position of the user according to multiple delay estimation values.

[0169] In actual implementation, there are different ways to obtain the user's spatial location based on multiple delay estimates.

[0170] In some possible embodiments, a deep training model can be obtained by deep learning a large amount of delay data in advance, and multiple delay estimation values ​​can be input into the deep training model to obtain the location information output by the deep training model as the user's spatial location, where the user's spatial location can be geographic coordinates, etc.

[0171] For example, in a specific application scenario, refer to Figure 5 When LMF (Location Management Services) is started, it sends parameters {d max , step}, where d max is a scenario parameter, and step represents the delay quantization interval. During positioning, the UE (User Equipment) periodically transmits an uplink SRS signal to the BS. BS i estimates the delay τ from the UE to it based on the received SRS reference signal. i , where i∈{1,2,...,N}, and then the delay τ i Report to the positioning server LMF. LMF is based on the delay parameters τ1, τ2,…, τ N The spatial position of the UE is calculated by using the UE_POSITION_SAT and other measurement values ​​(Note: other measurement values ​​are irrelevant to this application and are not described here).

[0172] In summary, the delay estimation method of the embodiment of the present application improves the accuracy of positioning based on high-precision delay estimation.

[0173] In order to implement the above-mentioned embodiments, the present application also proposes a terminal device, which can be a user's communication device, a base station or other device, or other cloud device.

[0174] In this embodiment, if Figure 6 As shown, the terminal device includes a memory 610, a transceiver 620, and a processor 630. The transceiver 620 is used to receive and send data under the control of the processor 630.

[0175] Among them, Figure 6In the embodiment, the bus architecture may include any number of interconnected buses and bridges, specifically one or more processors represented by processor 630 and various circuits of memory represented by memory 610 are linked together. The bus architecture may also link together various other circuits such as peripherals, voltage regulators, and power management circuits, which are well known in the art and are therefore not further described herein. The bus interface provides an interface. The transceiver 620 may be a plurality of components, namely, a transmitter and a receiver, providing a unit for communicating with various other devices on a transmission medium, which transmission medium may include a wireless channel, a wired channel, an optical cable, and other transmission media. The processor 630 is responsible for managing the bus architecture and general processing, and the memory 610 may store data used by the processor 630 when performing operations.

[0176] The processor 630 may be a central processing unit (CPU), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or a complex programmable logic device (CPLD). The processor may also adopt a multi-core architecture.

[0177] The processor calls the computer program stored in the memory to execute any resource configuration method provided in the embodiments of the present application according to the obtained executable instructions. The processor and the memory can also be arranged physically separately.

[0178] In an embodiment of the present application, the processor is used to:

[0179] The channel estimation value is determined based on the received reference signal. In this embodiment, the channel delay can obviously be reflected by the signal transmission status on the channel. Therefore, the corresponding channel estimation value can be determined according to the received reference signal.

[0180] Furthermore, the processor generates a matrix according to a preset maximum distance from the user to the base station and a delay quantization interval.

[0181] In this embodiment, in order to facilitate subsequent calculations, a matrix is ​​generated based on the preset maximum distance from the user to the base station and the delay quantization interval, wherein the method of generating the matrix of the maximum distance from the user to the base station and the delay quantization interval can be any method of splitting the multiple values ​​contained in the maximum distance and the delay quantization interval into matrix elements, which will be described in detail in subsequent embodiments and will not be repeated here.

[0182] Furthermore, the processor generates a signal spectrum space according to the channel estimation value and the matrix, that is, calculates the delay estimation value between the user and the base station in the signal spectrum space with richer dimensions. In some possible embodiments, the signal spectrum space p can be obtained by directly multiplying the channel estimation value and the matrix conjugate. new .

[0183] Finally, the processor searches for the peak in the signal spectrum space that is closest to the user's actual delay. The delay value corresponding to this peak is the user delay estimate. The method of finding the peak that is closest to the user's actual delay introduces a preset threshold value to filter interference information. The preset threshold value is calibrated according to the delay data and is related to the specific communication environment.

[0184] In one embodiment of the present application, the peak index closest to the actual user delay is found in the signal spectrum space, and the corresponding index can be calculated by the following formula (1), where thr is the threshold value for filtering interference, and the function findpeak represents the search for the signal spectrum space p new The index corresponding to the first peak whose size exceeds thr. The index can be understood as any unique information that identifies the peak, for example, it can be a digital number, etc.:

[0185] index=findpeak(p new ,thr) Formula (1)

[0186] Further, a corresponding delay estimation value is determined according to the index corresponding to the first peak, wherein the delay estimation value is represented by τ in subsequent embodiments, and the unit is seconds.

[0187] In summary, the terminal device of the embodiment of the present application determines the channel estimation value based on the received reference signal, generates a matrix according to the preset maximum distance from the user to the base station and the delay quantization interval, and then generates a signal spectrum space according to the channel estimation value and the matrix, and finally, obtains the delay estimation value between the user and the base station based on the signal spectrum space and the preset threshold value. As a result, the accuracy of the delay estimation between the user's communication device and the base station is improved, and further, technical support is provided for compensating for the delay to improve the communication quality.

[0188] In the actual implementation process, as described in the above embodiment, the transmission status of the reference signal in the channel can be summarized to obtain a channel estimation value, and the parameters representing the transmission status of the reference signal may be different in different scenarios. Therefore, in different application scenarios, the channel estimation value is determined based on the received reference signal in different ways, and the examples are described as follows:

[0189] In this example, the processor determines the channel estimation value based on the received reference signal according to the first formula in different ways. As a possible implementation, the processor determines the channel estimation value based on the received reference signal according to the first formula.

[0190] The above-mentioned reference signal can be received in any manner, for example, the base station receives an uplink reference signal sent by a user, and determines a channel estimation value according to the uplink reference signal.

[0191] It can be understood that the base station receives an uplink reference signal sent by the user's communication device. The uplink reference signal can be any signal used to detect channel delay. Further, the channel estimation value can be determined according to the uplink reference signal.

[0192] In this example, the user may also receive a downlink reference signal sent by the base station and determine a channel estimation value according to the downlink reference signal.

[0193] In this embodiment, the user's communication device receives a downlink reference signal sent by a base station. The downlink reference signal may be any signal used to detect channel delay. Further, a channel estimation value may be determined according to the downlink reference signal.

[0194] Similarly, in different application scenarios, the processor generates a matrix in different ways according to the preset maximum distance from the user to the base station and the delay quantization interval. To facilitate the understanding of those skilled in the art, in this embodiment, in combination with the above example, how to generate a matrix according to the preset maximum distance from the user to the base station and the delay quantization interval is further illustrated:

[0195] In this example, the processor calculates the maximum distance from the user to the base station and the delay quantization interval according to the above-mentioned second formula to generate the maximum number of columns of the matrix, obtains the preset minimum number of columns of the matrix, calculates the target number of columns of the matrix according to the maximum number of columns and the minimum number of columns, and uses the number of subcarriers as the target number of rows of the matrix, and calculates the subcarrier interval and the delay quantization interval according to the third formula to generate a matrix that matches the target number of rows and the target number of columns.

[0196] Furthermore, in different application scenarios, the processor generates a signal spectrum space according to the channel estimation value and the matrix in different ways. To facilitate the understanding of those skilled in the art, the following describes how to generate a signal spectrum space according to the estimation value and the matrix based on the above example:

[0197] In this example, the processor generates a signal spectrum space for the channel estimation value and the matrix according to the fourth formula.

[0198] In order to facilitate the estimation of the time delay, in one embodiment of the present application, the M values ​​in the signal spectrum space may be normalized, wherein the normalization formula may be the above formula (9).

[0199] In one embodiment of the present application, in order to improve the stability of delay estimation, the minimum value of the signal can be obtained from the signal spectrum space, and N minimum values ​​of the signal are added before each signal in the signal spectrum space, where N ≥ 1. Thus, the number of signals in the signal spectrum space becomes N + M. For example, the minimum value of the signal P is obtained in the signal spectrum space. min , p min =min{p new}, then the signal spectrum space is updated to p new =[p min,1 p min,2 ,...,p min,N p new ].

[0200] In this embodiment, the processor obtains a delay estimation value between the user and the base station based on the signal spectrum space and a preset threshold value, including:

[0201] After obtaining the index corresponding to the first peak whose signal value exceeds the threshold value from the signal spectrum space according to the preset function, the index can be calculated according to the preset fifth formula to obtain the estimated value of the delay between the user and the base station, wherein the preset fifth formula can refer to the above formulas (10) and (11):

[0202] If index starts numbering from 1, then: τ=(index-N+M min -1)*10 -9 *step, if index starts numbering from 0, then: τ=(index-N+M min )*10 -9 *step.

[0203] In summary, the terminal device of the embodiment of the present application can flexibly select the method of calculating the parameters required for the delay estimation value according to the scenario requirements, thereby improving the practicality of the delay estimation.

[0204] Based on the above embodiments, the delay estimation of the present application can improve the accuracy of the delay estimation value, thereby providing technical support for accurate positioning.

[0205] In one embodiment of the present application, the processor obtains multiple delay estimation values ​​between the user and multiple base stations, and then obtains the spatial position of the user according to the multiple delay estimation values.

[0206] In summary, the processor of the embodiment of the present application improves the accuracy of positioning based on high-precision delay estimation.

[0207] In order to implement the above embodiment, the present application also proposes a delay estimation device. Figure 7 is a schematic diagram of the structure of a delay estimation device according to an embodiment of the present application. Figure 7 As shown, the delay estimation device includes: a determination module 710, a first generation module 720, a second generation module 730 and an acquisition module 740, wherein:

[0208] A determination module 710, configured to determine a channel estimation value based on a received reference signal;

[0209] In this embodiment, the delay of the channel can obviously be reflected by the transmission status of the signal on the channel. Therefore, the determination module 710 can determine the corresponding channel estimation value according to the received reference signal.

[0210] A first generating module 720, configured to generate a matrix according to a preset maximum distance from a user to a base station and a delay quantization interval;

[0211] In this embodiment, in order to facilitate subsequent calculations, the first generation module 720 generates a matrix based on the preset maximum distance from the user to the base station and the delay quantization interval, wherein the method of generating the matrix of the maximum distance from the user to the base station and the delay quantization interval can be any method of splitting the multiple values ​​contained in the maximum distance and the delay quantization interval into matrix elements.

[0212] A second generating module 730, configured to generate a signal spectrum space according to the channel estimation value and the matrix;

[0213] In this embodiment, the second generation module 730 generates a signal spectrum space according to the channel estimation value and the matrix, that is, the delay estimation value between the user and the base station is calculated in the signal spectrum space with richer dimensions. In some possible embodiments, the channel estimation value and the matrix can be directly conjugate multiplied to obtain the signal spectrum space p new .

[0214] The acquisition module 740 is used to acquire the estimated value of the time delay between the user and the base station based on the signal spectrum space and a preset threshold value.

[0215] In this embodiment, the second generation module 730 searches for the peak closest to the actual delay of the user in the signal spectrum space. The delay value corresponding to this peak is the user delay estimation value. The method of finding the peak closest to the actual delay of the user introduces a preset threshold value to filter the interference information. The preset threshold value is calibrated according to the delay data and is related to the specific communication environment, etc.

[0216] It should be noted that the division of units in the embodiments of the present application is schematic and is only a logical function division. There may be other division methods in actual implementation. In addition, each functional unit in each embodiment of the present application may be integrated into a processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0217] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a processor-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, server, or network device, etc.) or a processor (processor) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (Read-Only Memory, ROM), random access memory (Random Access Memory, RAM), disk or optical disk and other media that can store program codes.

[0218] It should be noted that the above explanation of the delay estimation method is also applicable to the delay estimation device in the embodiment of the present application. The implementation principle is similar and will not be repeated here.

[0219] In summary, the delay estimation device of the embodiment of the present application determines the channel estimation value based on the received reference signal, generates a matrix according to the preset maximum distance from the user to the base station and the delay quantization interval, and then generates a signal spectrum space according to the channel estimation value and the matrix, and finally, obtains the delay estimation value between the user and the base station based on the signal spectrum space and the preset threshold value. As a result, the accuracy of the delay estimation between the user's communication device and the base station is improved, and further, technical support is provided for compensating for the delay to improve the communication quality.

[0220] In order to implement the above embodiment, the present application also proposes a processor-readable storage medium. The processor-readable storage medium stores a computer program, and the computer program is used to enable the processor to execute the delay estimation method of the above embodiment.

[0221] The processor-readable storage medium can be any available medium or data storage device that can be accessed by the processor, including but not limited to magnetic storage (such as floppy disks, hard disks, magnetic tapes, magneto-optical disks (MO), etc.), optical storage (such as CD, DVD, BD, HVD, etc.), and semiconductor storage (such as ROM, EPROM, EEPROM, non-volatile memory (NANDFLASH), solid-state drive (SSD)), etc.

[0222] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage and optical storage, etc.) that contain computer-usable program code.

[0223] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer executable instructions. These computer executable instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0224] These processor executable instructions may also be stored in a processor readable memory that can direct a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the processor readable memory produce an article of manufacture including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0225] These processor-executable instructions may also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for executing on the computer or other programmable device to implement the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0226] The exemplary embodiments of the present application are described above in conjunction with the accompanying drawings, including various details of the embodiments of the present application to facilitate understanding, which should be considered as merely exemplary. Therefore, it should be recognized by those of ordinary skill in the art that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present application. Similarly, for the sake of clarity and conciseness, the description of well-known functions and structures is omitted in the following description.

Claims

1. A delay estimation method, characterized in that: The method comprises: determining a channel estimate based on the received reference signal; Generate a matrix according to a preset maximum distance from the user to the base station and a delay quantization interval; Generate a signal spectrum space according to the channel estimation value and the matrix; generating the signal spectrum space according to the channel estimation value and the matrix comprises: conjugate multiplying the channel estimation value and the matrix to obtain the signal spectrum space; Acquire a delay estimation value between the user and the base station based on the signal spectrum space and a preset threshold value; The generating a matrix according to the preset maximum distance from the user to the base station and the delay quantization interval includes: The maximum distance from the user to the base station and the delay quantization interval are calculated according to the second formula to generate the maximum number of columns of the matrix, wherein the second formula includes: M max = floor(d max / c * 10 9 / step) or, M max =ceil(d max / c*10 9 / step) or, M max =round(d max / c*10 9 / step), Where c = 3 × 10 8 Meters / second, floor means round down, ceil means round up, round means round up, d max is a scene parameter, step represents the delay quantization interval; Get the minimum number of columns of the preset matrix; Calculating a target number of columns of the matrix according to the maximum number of columns and the minimum number of columns, and using the number of subcarriers as a target number of rows of the matrix; The subcarrier spacing and the delay quantization spacing are calculated according to a third formula to generate a matrix matching the target number of rows and the target number of columns, wherein the third formula includes: Where k = 0, 1, ..., N SC -1; Δf is the subcarrier spacing, the unit is Hz; m is an integer, the value range is M min ≤m≤M max , where M min The default minimum number of columns.

2. The method according to claim 1, characterized in that The determining of a channel estimation value based on a received reference signal comprises: The base station receives an uplink reference signal sent by a user, and determines a channel estimation value according to the uplink reference signal; or, The user receives a downlink reference signal sent by the base station, and determines a channel estimation value according to the downlink reference signal.

3. The method according to claim 1, characterized in that Determine a channel estimation value based on a received reference signal according to a first formula, wherein the first formula includes: h(i)=r(i)*conj(s(i)),i=1,2,......,N SC Where i is the subcarrier index, r is the received reference signal sequence, s is the local reference signal sequence, h is the estimated channel, N SC Indicates the number of subcarriers.

4. The method according to claim 1, characterized in that Generate a signal spectrum space for the channel estimation value and the matrix according to a fourth formula, wherein the fourth formula includes: Among them, m=0,1,2,......,M-1.

5. The method according to claim 4, characterized in that Also includes: The M values ​​in the signal spectrum space are normalized.

6. The method according to claim 5, characterized in that Also includes: Obtaining a signal minimum value from the signal spectrum space; Add N minimum values ​​of the signal before each signal in the signal spectrum space.

7. The method according to claim 6, characterized in that The acquiring the estimated value of the time delay between the user and the base station based on the signal spectrum space and a preset threshold value includes: Acquire, from the signal spectrum space according to a preset function, an index corresponding to the first peak whose signal value exceeds the threshold value; The index is calculated according to a preset fifth formula to obtain an estimated value of the delay between the user and the base station, wherein: The fifth formula includes: If the index starts numbering from 1, then: τ=(index-N+M min -1)*10 -9 *step If the index starts numbering from 0, then: τ=(index-N+M min )*10 -9 *step, Here, step represents the delay quantization interval.

8. The method according to any one of claims 1 to 7, characterized in that: Also includes: Acquire multiple delay estimation values ​​between the user and multiple base stations; The spatial position of the user is acquired according to the multiple delay estimation values.

9. A terminal device, characterized in that: Including memory, transceiver, processor: The memory is used to store computer programs; the transceiver is used to send and receive data under the control of the processor; A processor is configured to read the computer program in the memory and perform the following operations: determining a channel estimate based on the received reference signal; Generate a matrix according to a preset maximum distance from the user to the base station and a delay quantization interval; Generate a signal spectrum space according to the channel estimation value and the matrix; Generating a signal spectrum space according to the channel estimation value and the matrix comprises: conjugate multiplying the channel estimation value and the matrix to obtain the signal spectrum space; Acquire a delay estimation value between the user and the base station based on the signal spectrum space and a preset threshold value; The generating a matrix according to the preset maximum distance from the user to the base station and the delay quantization interval includes: The maximum distance from the user to the base station and the delay quantization interval are calculated according to the second formula to generate the maximum number of columns of the matrix, wherein the second formula includes: M max = floor(d max / c * 10 9 / step) or, M max =ceil(d max / c*10 9 / step) or, M max =round(d max / c*10 9 / step), Where c = 3 × 10 8 Meters / second, floor means round down, ceil means round up, round means round up, d max is a scene parameter, step represents the delay quantization interval; Get the minimum number of columns of the preset matrix; Calculating a target number of columns of the matrix according to the maximum number of columns and the minimum number of columns, and using the number of subcarriers as a target number of rows of the matrix; The subcarrier spacing and the delay quantization spacing are calculated according to a third formula to generate a matrix matching the target number of rows and the target number of columns, wherein the third formula includes: Where k = 0, 1, ..., N SC -1; Δf is the subcarrier spacing, the unit is Hz; m is an integer, the value range is M min ≤m≤M max , where M min The default minimum number of columns.

10. The device according to claim 9, characterized in that The determining of a channel estimation value based on a received reference signal comprises: The base station receives an uplink reference signal sent by a user, and determines a channel estimation value according to the uplink reference signal; or, The user receives a downlink reference signal sent by the base station, and determines a channel estimation value according to the downlink reference signal.

11. The device according to claim 9, characterized in that Determine a channel estimation value based on a received reference signal according to a first formula, wherein the first formula includes: h(i)=r(i)*conj(s(i)),i=1,2,......,N SC Where i is the subcarrier index, r is the received reference signal sequence, s is the local reference signal sequence, h is the estimated channel, N SC Indicates the number of subcarriers.

12. The device according to claim 9, characterized in that Generate a signal spectrum space for the channel estimation value and the matrix according to a fourth formula, wherein the fourth formula includes: Among them, m=0,1,2,......,M-1.

13. The device according to claim 12, characterized in that Also includes: The M values ​​in the signal spectrum space are normalized.

14. The device according to claim 13, characterized in that Also includes: Obtaining a signal minimum value from the signal spectrum space; Add N minimum values ​​of the signal before each signal in the signal spectrum space.

15. The device according to claim 14, characterized in that The acquiring the estimated value of the time delay between the user and the base station based on the signal spectrum space and a preset threshold value includes: Acquire, from the signal spectrum space according to a preset function, an index corresponding to the first peak whose signal value exceeds the threshold value; The index is calculated according to a preset fifth formula to obtain an estimated value of the delay between the user and the base station, wherein the fifth formula includes: If the index starts numbering from 1, then: τ=(index-N+M min -1)*10 -9 *step If the index starts numbering from 0, then: τ=(index-N+M min )*10 -9 *step, Here, step represents the delay quantization interval.

16. The device according to any one of claims 9 to 15, characterized in that: Also includes: Acquire multiple delay estimation values ​​between the user and multiple base stations; The spatial position of the user is acquired according to the multiple delay estimation values.

17. A delay estimation device, characterized in that: The device comprises: A determination module, configured to determine a channel estimation value based on a received reference signal; A first generating module, used to generate a matrix according to a preset maximum distance from a user to a base station and a delay quantization interval; A second generating module is used to generate a signal spectrum space according to the channel estimation value and the matrix; the second generating module is used to: conjugate multiply the channel estimation value and the matrix to obtain the signal spectrum space; An acquisition module, used to acquire an estimated value of the time delay between the user and the base station based on the signal spectrum space and a preset threshold value; Wherein, the first generating module is used for: The maximum distance from the user to the base station and the delay quantization interval are calculated according to the second formula to generate the maximum number of columns of the matrix, wherein the second formula includes: M max = floor(d max / c * 10 9 / step) or, M max =ceil(d max / c*10 9 / step) or, M max =round(d max / c*10 9 / step), Where c = 3 × 10 8 Meters / second, floor means round down, ceil means round up, round means round up, d max is a scene parameter, step represents the delay quantization interval; Get the minimum number of columns of the preset matrix; Calculating a target number of columns of the matrix according to the maximum number of columns and the minimum number of columns, and using the number of subcarriers as a target number of rows of the matrix; The subcarrier spacing and the delay quantization spacing are calculated according to a third formula to generate a matrix matching the target number of rows and the target number of columns, wherein the third formula includes: Where k = 0, 1, ..., N SC -1; Δf is the subcarrier spacing, the unit is Hz; m is an integer, the value range is M min ≤m≤M max , where M min The default minimum number of columns.

18. A processor-readable storage medium, characterized in that: The processor-readable storage medium stores a computer program, and the computer program is used to enable the processor to execute the delay estimation method according to any one of claims 1 to 8.

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