A UWB signal detection and frequency deviation estimation method

Abstract

The present invention discloses a UWB signal detection and frequency deviation estimation method, which relates to the field of ultra-wideband communication positioning technology, and includes the following steps: S1: after the data output by the ADC is processed, the data of two adjacent symbols are conjugate multiplied; S2: the result of the symbol conjugate multiplication is accumulated and stored in the first sliding window; S3: according to the set calculation frequency, the data in the first sliding window is summed and stored in the second sliding window; S4: the absolute value of the data in the second sliding window is calculated, and the amplitude growth rate is calculated to see whether it meets the set threshold value. If the amplitude growth rate is greater than the set threshold value, the signal detection is successful; if the amplitude growth rate is not greater than the set threshold value, the detection is continued until the detection timeout; S5: after the signal detection is successful, the last data in the second sliding window is extracted, and the frequency deviation estimation result is calculated. The present invention adopts the above method, which can be unaffected by the frequency deviation and has strong robustness; the calculation complexity is extremely low, and it is particularly suitable for low power consumption scenarios.

Description

Technical Field

[0001] The present invention relates to the technical field of ultra-wideband communication positioning, and in particular to a UWB signal detection and frequency deviation estimation method. Background Art

[0002] At present, the outdoor positioning technology based on GNSS is relatively mature, but indoors, the satellite signal is easily blocked and cannot complete the normal positioning service, and the positioning accuracy cannot meet the service requirements. In recent years, people's demand for high-precision positioning services has become stronger. According to statistics, 70%-80% of people's activities take place indoors, so it is of great significance to develop indoor positioning technology. Based on various needs, many corresponding positioning technologies have been demonstrated and have achieved good results, such as infrared, radio frequency identification, ultrasound, WIFI, Bluetooth, Zigbee, visual positioning and other technologies. However, they all have their own curves, either low positioning accuracy or harsh requirements on the environment, which cannot meet people's requirements for high accuracy and good environmental adaptability of indoor positioning perception systems. The many advantages of UWB positioning technology are that this technology can achieve high-precision indoor positioning. Compared with other wireless positioning technologies, UWB has many advantages such as strong anti-interference ability, extremely wide bandwidth, fast transmission rate, and low power consumption;

[0003] However, as a wireless communication technology, the sensitivity of the signal detection method is directly related to the ranging range of UWB. The robustness of the signal detection method is of great significance for improving communication quality and building a robust communication system. Signal detection is the first gateway to identify signals. High-reliability signal detection methods can ensure low false detection rate and low missed detection rate in a multi-interference environment.

[0004] However, current UWB signal detection methods are easily affected by frequency offset.

[0005] Therefore, it is necessary to provide a UWB signal detection and frequency offset estimation method to solve the above problems. Summary of the invention

[0006] The purpose of the present invention is to provide a UWB signal detection and frequency deviation estimation method, which is not affected by frequency deviation and has strong robustness; in the real-time signal processing process, each data input only needs to calculate one multiplication and one addition, the calculation complexity is extremely low, and it is particularly suitable for low power consumption scenarios; in the data processing process, only the data of one symbol needs to be cached, and the system memory consumption is small; while completing the signal detection, the current frequency deviation can be estimated, which is conducive to simplifying the overall system design.

[0007] To achieve the above object, the present invention provides a UWB signal detection and frequency offset estimation method, which is characterized by comprising the following steps:

[0008] S1: After the data output by the ADC is processed, the data of two adjacent symbols are conjugate multiplied; the calculation of the conjugate multiplication is as follows:

[0009] S(i)=conj(A(i))*A(i+N smp )

[0010] Where A(i) is the data after ADC output processing, A(i) is a complex number, i represents the data index, N smp is the number of sampling points of a symbol, conj(x) is the conjugate operation of x;

[0011] S2: Accumulate the results of the sign conjugate multiplication and store them in the first sliding window;

[0012] S3: summing the data in the first sliding window according to the set calculation frequency and storing it in the second sliding window;

[0013] S4: Calculate the absolute value of the data in the second sliding window and calculate whether the amplitude growth rate meets the set threshold. If the amplitude growth rate is greater than the set threshold, the signal detection is successful; if the amplitude growth rate is not greater than the set threshold, continue to detect until the detection times out;

[0014] S5: After the signal detection is successful, the last data in the second sliding window is extracted and the frequency offset estimation result is calculated.

[0015] Preferably, in step S2, the specific steps of accumulating the sign conjugate multiplication results are as follows:

[0016] Set a counter C smp , counter C smp From 1 to N smp Cycle counting between the two, each time the ADC outputs a sampling point, the counter C smp Increase by 1, when counter C smp Reach N smp , the next counter C smp The count value of the symbol counter C is 1, and symb Increase by 1;

[0017] The cumulative sum S of the sign conjugate multiplication results sum (C symb )for:

[0018]

[0019] Preferably, in step S2, the cumulative sum S of the sign conjugate multiplication results is sum (C symb ) is stored in the first sliding window, and the storing method comprises the following steps:

[0020] S21: Shift and register the data in the first sliding window win1 (1:(N win1 -1))=S win1 (2:N win1 );

[0021] S22: The latest accumulated result S sum (C symb ) is stored in S win1 (N win1 )middle;

[0022] Among them, N win1 represents the window length of the first sliding window, S win1 (1:(N win1 -1)) indicates the window index 1 to (N win1 -1) Index data, S win1 (2:N win1 ) indicates the index 2 to N in the window win1 Index data, S win1 (1:(N win1 -1))=S win1 (2:N win1 ) represents index 2 to N win1 The indexed data is shifted and stored at index 1 to (N win1 -1)Indexing.

[0023] Preferably, in step S3, the specific steps are as follows:

[0024] Set the calculation frequency to N calc , when rem(C symb , N calc )=0, the data in the second sliding window is shifted and stored S win2 (1:(N win2 -1))=S win2 (2:N win2 ), then the data in the first sliding window is summed and stored in the second sliding window:

[0025]

[0026] Among them, rem(x, y) is the operation of calculating the remainder of x / y when the dividend is x and the divisor is y. win2 is the window length of the second sliding window, and τ is a temporary variable used to traverse the data in the first sliding window.

[0027] Preferably, in step S4, the specific steps are as follows:

[0028] S41: Calculate the absolute value of the data in the second sliding window:

[0029] S′ win2 (k) = abs(S win2 (k))

[0030] Wherein, k represents the index value of the data in the second sliding window, and abs(x) is the absolute value operation of x;

[0031] S42: Calculate the growth rate of the data in the sliding window based on the calculated absolute value:

[0032]

[0033] Among them, max(x, y) is the maximum value of x and y, d min Represents S′ win2 The least significant value in the window other than zero. m is a temporary variable used to traverse S′ win2 (k) all data;

[0034] S43: Calculate the minimum value of the second sliding window data growth rate:

[0035] R min =min([R win2 (1), R win2 (2), ..., R win2 (N win2 -1)])

[0036] Among them, min(x) is the minimum value of the x sequence;

[0037] S44: Use R min With the set growth rate threshold R th For comparison, if R min >R th , signal detection is successful, R min ≤R th , the detection continues until the detection times out.

[0038] Preferably, in step S5, the frequency offset estimation result is calculated in the following manner:

[0039]

[0040] Where ppm represents the carrier frequency deviation, phase(x) represents the conversion of the complex number x into radians, and f smp Indicates the ADC sampling frequency, f c Indicates the RF carrier frequency.

[0041] Therefore, the present invention adopts the above-mentioned UWB signal detection and frequency deviation estimation method, which has the following beneficial effects:

[0042] (1) The present invention is not affected by frequency deviation and has strong robustness.

[0043] (2) In the real-time signal processing process of the present invention, only one multiplication and one addition are required for each data input, and the computational complexity is extremely low, which is particularly suitable for low-power consumption scenarios.

[0044] (3) During the data processing process of the present invention, only the data of one symbol needs to be cached, which consumes less system memory.

[0045] (4) The present invention can estimate the current frequency offset while completing signal detection, which is helpful to simplify the overall system design.

[0046] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 It is a flow chart of a UWB signal detection and frequency deviation estimation method of the present invention;

[0048] Figure 2 This is the first window data processing process of the UWB signal detection and frequency offset estimation method of the present invention;

[0049] Figure 3 This is the second window data processing process of the UWB signal detection and frequency deviation estimation method of the present invention. DETAILED DESCRIPTION

[0050] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0051] Unless otherwise defined, technical or scientific terms used in the present invention shall have the common meanings understood by persons having ordinary skills in the field to which the present invention belongs.

[0052] The words "include" or "comprising" and the like used in the present invention mean that the elements before the word include the elements listed after the word, and do not exclude the possibility of also including other elements. The directions or positional relationships indicated by the terms "inside", "outside", "upper", "lower", etc. are based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention. When the absolute position of the described object changes, the relative positional relationship may also change accordingly. In the present invention, unless otherwise clearly specified and limited, the terms "attachment" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral body; it can be directly connected or indirectly connected through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0053] Example

[0054] like Figure 1 As shown, the present invention provides a UWB signal detection and frequency offset estimation method, comprising the following steps:

[0055] S1: After the data output by the ADC is processed, the data of two adjacent symbols are conjugate multiplied; the calculation of the conjugate multiplication is as follows:

[0056] S(i)=conj(A(i))*A(i+N smp )

[0057] Where A(i) is the data after ADC output processing, A(i) is a complex number, i represents the data index, N smp is the number of sampling points of a symbol, conj(x) is the conjugate operation of x;

[0058] S2: Accumulate the results of the sign conjugate multiplication and store them in the first sliding window; Figure 2 As shown, in step S2, the specific steps of accumulating the sign conjugate multiplication results are as follows:

[0059] Set a counter C smp , counter C smp From 1 to N smp Cycle counting between the two, each time the ADC outputs a sampling point, the counter C smp Increase by 1, when counter C smp Reach N smp , the next counter C smp The count value of the symbol counter C is 1, and symb Increase by 1;

[0060] The cumulative sum S of the sign conjugate multiplication results sum (C symb )for:

[0061]

[0062] In step S2, the cumulative sum S of the sign conjugate multiplication results is sum (C symb ) is stored in the first sliding window, and the storing method comprises the following steps:

[0063] S21: Shift and register the data in the first sliding window win1 (1:(N win1 -1))=S win1 (2:N win1 );

[0064] S22: The latest accumulated result S sum (C symb ) is stored in S win1 (N win1 )middle;

[0065] Among them, N win1 represents the window length of the first sliding window, S win1 (1:(N win1 -1)) indicates the window index 1 to (N win1 -1) Index data, S win1 (2:N win1 ) indicates the index 2 to N in the window win1 Index data, S win1 (1:(N win1 -1))=S win1 (2:N win1 ) represents index 2 to N win1 The indexed data is shifted and stored at index 1 to (N win1 -1)In the index, N win1 =8.

[0066] S3: According to the set calculation frequency, the data in the first sliding window is summed and stored in the second sliding window; in step S3, if Figure 3 As shown, the specific steps are as follows:

[0067] Set the calculation frequency to N calc , when rem(C symb , N calc )=0, the data in the second sliding window is shifted and stored S win2 (1:(N win2 -1))=S win2 (2:Nwin2 ), then the data in the first sliding window is summed and stored in the second sliding window:

[0068]

[0069] Among them, rem(x, y) is the operation of calculating the remainder of x / y when the dividend is x and the divisor is y. win2 is the window length of the second sliding window, and τ is a temporary variable used to traverse the data in the first sliding window. calc =2,N win2 =4.

[0070] S4: Calculate the absolute value of the data in the second sliding window and calculate whether the amplitude growth rate meets the set threshold. If the amplitude growth rate is greater than the set threshold, the signal detection is successful; if the amplitude growth rate is not greater than the set threshold, continue to detect until the detection times out. In step S4, the specific steps are as follows:

[0071] S41: Calculate the absolute value of the data in the second sliding window:

[0072] S′ win2 (k) = abs(S win2 (k))

[0073] Wherein, k represents the index value of the data in the second sliding window, and abs(x) is the absolute value operation of x;

[0074] S42: Calculate the growth rate of the data in the sliding window based on the calculated absolute value:

[0075]

[0076] Among them, max(x, y) is the maximum value of x and y, d min Represents S′ win2 The least significant value in the window other than zero. m is a temporary variable used to traverse S′ win2 (K) all data;

[0077] S43: Calculate the minimum value of the second sliding window data growth rate:

[0078] R min =min([R win2 (1), R win2 (2), ..., R win2 (N win2 -1)])

[0079] Among them, min(x) is the minimum value of the x sequence;

[0080] S44: Use R min With the set growth rate threshold Rth For comparison, if R min >R th , signal detection is successful, R min ≤R th , the detection continues until the detection times out.

[0081] S5: After the signal detection is successful, extract the last data in the second sliding window and calculate the frequency offset estimation result. In step S5, the frequency offset estimation result is calculated as follows:

[0082]

[0083] Where ppm represents the carrier frequency deviation, phase(x) represents the conversion of the complex number x into radians, and f smp Indicates the ADC sampling frequency, f c Indicates the RF carrier frequency.

[0084] Therefore, the present invention adopts the above-mentioned UWB signal detection and frequency deviation estimation method, which is not affected by frequency deviation and has strong robustness; in the real-time signal processing process, each data input only needs to calculate one multiplication and one addition, and the calculation complexity is extremely low, which is particularly suitable for low-power consumption scenarios; in the data processing process, only the data of one symbol needs to be cached, and the system memory consumption is small; while completing the signal detection, the current frequency deviation can be estimated, which is conducive to simplifying the overall system design.

[0085] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A UWB signal detection and frequency offset estimation method, characterized in that: The following steps are involved: S1: After the data output by the ADC is processed, the data of two adjacent symbols are conjugate multiplied; the calculation of the conjugate multiplication is as follows: S(i)=conj(A(i))*A(i+N smp ) Where A(i) is the data after ADC output processing, A(i) is a complex number, i represents the data index, N smp is the number of sampling points of a symbol, conj(x) is the conjugate operation of x; S2: Accumulate the results of the sign conjugate multiplication and store them in the first sliding window; S3: summing the data in the first sliding window according to the set calculation frequency and storing it in the second sliding window; S4: Calculate the absolute value of the data in the second sliding window and calculate whether the amplitude growth rate meets the set threshold. If the amplitude growth rate is greater than the set threshold, the signal detection is successful; if the amplitude growth rate is not greater than the set threshold, continue to detect until the detection times out; S5: After the signal detection is successful, the last data in the second sliding window is extracted and the frequency offset estimation result is calculated.

2. A UWB signal detection and frequency offset estimation method according to claim 1, characterized in that: In step S2, the specific steps of accumulating the sign conjugate multiplication results are as follows: Set a counter C smp , counter C smp From 1 to N smp Cycle counting between the two, each time the ADC outputs a sampling point, the counter C smp Increase by 1, when counter C smp Reach N smp , the next counter C smp The count value of the symbol counter C is 1, and symb Increase by 1; The cumulative sum S of the sign conjugate multiplication results sum (C symb )for:

3. A UWB signal detection and frequency offset estimation method according to claim 2, characterized in that: In step s2, the accumulated sum S of the sign conjugate multiplication results is sum (C symb ) is stored in the first sliding window, and the storing method comprises the following steps: S21: Shift and register the data in the first sliding window win1 (1:(N win1 —1))=S win1 (2:N win1 ); S22: The latest accumulated result S sum (C symb ) is stored in S win1 (N win1 )middle; Among them, N win1 represents the window length of the first sliding window, S win1 (1:(N win1 —1)) indicates the window index 1 to (N win1 —1) Index data, S win1 (2:N win1 ) indicates the index 2 to N in the window win1 Index data, S win1 (1:(N win1 —1))=S win1 (2:N win1 ) represents index 2 to N win1 The indexed data is shifted and stored at index 1 to (N win1 —1)Indexing.

4. A UWB signal detection and frequency offset estimation method according to claim 3, characterized in that: In step s3, the specific steps are as follows: Set the calculation frequency to N calc , when rem(C symb , N calc )=0, the data in the second sliding window is shifted and stored S win2 (1:(N win2 —1))=S win2 (2:N win2 ), then the data in the first sliding window is summed and stored in the second sliding window: Among them, rem(x, y) is the operation of calculating the remainder of x / y when the dividend is x and the divisor is y. win2 is the window length of the second sliding window, and τ is a temporary variable used to traverse the data in the first sliding window.

5. A UWB signal detection and frequency offset estimation method according to claim 4, characterized in that: In step S4, the specific steps are as follows: S41: Calculate the absolute value of the data in the second sliding window: S′ win2 (k)=abs(S win2 (k)) Wherein, k represents the index value of the data in the second sliding window, and abs(x) is the absolute value operation of x; S42: Calculate the growth rate of the data in the sliding window based on the calculated absolute value: Among them, max(x, y) is the maximum value of x and y, d min Represents S′ win2 The least significant value in the window other than zero. m is a temporary variable used to traverse S′ win2 (k) all data; S43: Calculate the minimum value of the second sliding window data growth rate: R min =min([R win2 (1),R win2 (2),...,R win2 (N win2 —1)]) Among them, min(x) is the minimum value of the x sequence; S44: Use R min With the set growth rate threshold R th For comparison, if R min >R th , signal detection is successful, R min ≤R th , the detection continues until the detection times out.

6. A UWB signal detection and frequency offset estimation method according to claim 5, characterized in that: In step S5, the frequency offset estimation result is calculated as follows: Where ppm represents the carrier frequency deviation, phase(x) represents the conversion of the complex number x into radians, and f smp Indicates the ADC sampling frequency, f c Indicates the RF carrier frequency.

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