A frequency offset self-compensating UWB signal detection method

Abstract

This invention discloses a frequency offset self-compensation method for UWB signal detection, belonging to the field of ultra-wideband communication technology. The method includes the following steps: First, cross-correlation is performed between the ADC-sampled signal and the local sequence; second, based on the peak detection position, the phase difference is calculated using the calculated cross-correlation result and the cross-correlation result of the previous symbol; then, phase compensation is performed on the currently calculated cross-correlation result; next, the phase-compensated cross-correlation result is added at the same position to the cross-correlation result of the previous symbol; then, peak period detection is performed using the added cross-correlation result, updating the peak detection position and peak period detection count; the phase compensation value is updated based on the peak period detection count and the calculated phase difference; finally, it is determined whether the peak period detection count has reached a set threshold. If it has, the signal detection result is output; otherwise, steps 1-7 are repeated.

Description

Technical Field

[0001] This invention belongs to the field of ultra-wideband (UWB) communication technology, and in particular relates to a frequency offset self-compensation UWB signal detection method. Background Technology

[0002] Currently, GNSS-based outdoor positioning technology is relatively mature. However, indoors, satellite signals are easily blocked, making normal positioning services impossible and the positioning accuracy insufficient to meet service requirements. In recent years, the demand for high-precision positioning services has become increasingly strong. Statistics show that 70%-80% of people's activities occur indoors, making the development of indoor positioning technology of great significance. Based on various needs, many corresponding positioning technologies have emerged and achieved good results, such as infrared, radio frequency identification, ultrasound, WIFI, Bluetooth, Zigbee, and visual positioning technologies. However, each has its own limitations, either having low positioning accuracy or being highly dependent on the environment, failing to meet people's requirements for high accuracy and good environmental adaptability in indoor positioning sensing systems. UWB positioning technology has many advantages, enabling high-precision indoor positioning. Compared to other wireless positioning technologies, UWB has many advantages such as strong anti-interference capabilities, extremely wide bandwidth, high transmission rate, and low power consumption.

[0003] However, UWB technology is also a type of wireless communication technology. A key technology in wireless communication is signal detection. The robustness of signal detection methods is crucial for improving communication quality and building robust communication systems. As the first gateway for signal identification, highly reliable signal detection methods can ensure low false detection and low false detection rates in low signal-to-noise ratio environments. The sensitivity of the signal detection method directly affects the ranging range of UWB and its application in complex scenarios. Therefore, low-complexity and high-reliability signal detection methods have always been one of the main research directions in wireless communication technology. Summary of the Invention

[0004] The purpose of this invention is to provide a frequency offset self-compensating UWB signal detection method to solve the problems of low positioning accuracy, stringent environmental requirements, and inability to meet people's requirements for high accuracy and good environmental adaptability of indoor positioning and sensing systems.

[0005] To achieve the above objectives, the present invention provides a UWB signal detection method with frequency offset self-compensation, comprising the following steps:

[0006] Step 1: Perform cross-correlation calculation on the ADC-sampled signal and the local sequence;

[0007] Step 2: Based on the peak detection position, calculate the phase difference using the calculated cross-correlation result and the cross-correlation result of the previous symbol;

[0008] Step 3: Perform phase compensation on the currently calculated cross-correlation results using the phase compensation value;

[0009] Step 4: Add the cross-correlation result after phase compensation to the cross-correlation result of the previous symbol at the same position;

[0010] Step 5: Use the summed cross-correlation results to perform peak period detection, and update the peak detection position and peak period detection count value;

[0011] Step 6: Update the phase compensation value based on the peak period detection count value and the calculated phase difference;

[0012] Step 7: Determine whether the peak period detection count value has reached the set threshold. If it has reached the set threshold, output the signal detection result; if it has not reached the threshold, repeat steps 1-7.

[0013] Preferably, the calculation expression for the cross-correlation operation in step 1 is as follows:

[0014]

[0015] Among them, S C For the result of cross-correlation calculation, s sig S is the signal sampled by the ADC. loc For local sequences, N smp The number of sampling points contained in one symbol period.

[0016] Preferably, in step 2, the calculation of the phase difference based on the peak detection position using the calculated cross-correlation result and the cross-correlation result calculated for the previous symbol includes the following cases:

[0017] When Pidx < 0

[0018] When Pidx = 0, the calculation method is as follows:

[0019]

[0020] When 0 <Pidx<N smp When the value is -1, the calculation method is as follows:

[0021]

[0022] When Pidx = N smp When the value is -1, the calculation method is as follows:

[0023]

[0024] in, For calculating the phase difference, angle() is the method to convert a complex number to radians, conj() is the method to take the conjugate, Pidx is the index of the current peak detection position, and S' C S″ represents the cross-correlation result of the current symbol. C N is the cross-correlation result of the previous symbol. smp The number of sampling points contained in one symbol period.

[0025] Preferably, the specific process of performing phase compensation on the currently calculated cross-correlation result using the phase compensation value in step 3 is as follows:

[0026] When idx≥Pidx-1&&idx≤Pidx+1

[0027]

[0028] otherwise

[0029] S(idx)=S′ C (idx)

[0030] S is related to S' C The corresponding value after phase compensation, Here, idx is the phase compensation value, and idx is the data index value of the cross-correlation result within one symbol, ranging from 0 to N. smp -1.

[0031] Preferably, the specific expression for adding the cross-correlation result after phase compensation in step 4 to the cross-correlation result of the previous symbol at the same position is as follows:

[0032] When C peak When = 0,

[0033] S Add (idx)=abs(S(idx))+abs(S″ C (idx))

[0034] When C peak >0

[0035] S Add (idx)=abs(S(idx)+S″ C (idx))

[0036] Among them, S Add The result is the sum of the cross-correlation results of the two symbols at the same position, where idx is the data index of the cross-correlation result in a symbol, and C is the result of the cross-correlation results at the same position. peakTo update the peak period detection count value, abs() performs the absolute value operation, S' C S″ represents the cross-correlation result of the current symbol. C S is the cross-correlation result of the previous symbol, and S' is the result of the cross-correlation with S'. C The corresponding value after phase compensation.

[0037] Preferably, the specific process of updating the phase compensation value in step 6 based on the peak period detection count value and the calculated phase difference is as follows:

[0038] S601, Determine the peak period detection count value C peak Is it 0?

[0039] S602, when the peak period detection count value C peak When = 0, the output phase compensation value is

[0040] S603, When the peak period detection count value C peak When ≠0, continue with C. peak Is it less than C'? peak ;

[0041] S604, When the peak period detection count value C peak <C' peak If the output phase compensation value is not updated, then

[0042] S605, When the peak period detection count value C peak ≥C' peak Continue to judge C. peak Is it equal to 1?

[0043] S606, When the peak period detection count value C peak When = 1, the output phase compensation value is

[0044] S607. Otherwise, update the phase compensation value.

[0045] Where, φ' c The phase compensation value before the update; C' peak The peak period detection count value before the update; The phase difference is calculated.

[0046] Therefore, the UWB signal detection method with frequency offset self-compensation described above, as used in this invention, has the following beneficial effects:

[0047] (1) The sensitivity of signal detection was improved by applying peak enhancement technology to the cross-correlation results;

[0048] (2) By performing carrier frequency offset estimation simultaneously with signal detection, the impact of carrier frequency offset on signal detection is reduced, while providing coarse estimation results of carrier frequency offset, which helps to improve the convergence speed of subsequent carrier frequency offset estimation.

[0049] (3) While ensuring high performance, this method maintains low implementation complexity, which is beneficial to the implementation of practical engineering.

[0050] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0051] Figure 1 This is an overall flowchart of a frequency offset self-compensating UWB signal detection method according to the present invention;

[0052] Figure 2 This is a schematic diagram showing the addition of cross-correlation results at the same position in a frequency offset self-compensation UWB signal detection method according to the present invention;

[0053] Figure 3 This is a flowchart of the phase compensation value update process for a frequency offset self-compensating UWB signal detection method according to the present invention. Detailed Implementation

[0054] The following detailed description of embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0055] See also Figure 1-3 A frequency offset self-compensating UWB signal detection method includes the following steps:

[0056] Step 1: Perform a cross-correlation operation on the ADC-sampled signal and the local sequence; the calculation expression for the cross-correlation operation is as follows:

[0057]

[0058] Among them, S C For the result of cross-correlation calculation, s sig S is the signal sampled by the ADC. loc For local sequences, N smp The number of sampling points contained in one symbol period;

[0059] Step 2: Based on the peak detection position, calculate the phase difference using the calculated cross-correlation result and the cross-correlation result of the previous symbol; where the peak detection position Pidx comes from the feedback in step 5. Initially, when there is no feedback, the initial value of Pidx is -1. When calculating the phase difference using the calculated cross-correlation result and the cross-correlation result of the previous symbol, it is first necessary to check if Pidx is reasonable. If Pidx < 0, then output...

[0060] When Pidx = 0, the calculation method is as follows:

[0061]

[0062] When 0 <Pidx<N smp When the value is -1, the calculation method is as follows:

[0063]

[0064] When Pidx = N smp When the value is -1, the calculation method is as follows:

[0065]

[0066] in, For calculating the phase difference, angle() is the method to convert a complex number to radians, conj() is the method to take the conjugate, Pidx is the index of the current peak detection position, and S' C S″ represents the cross-correlation result of the current symbol. C N is the cross-correlation result of the previous symbol. smp The number of sampling points contained in one symbol period;

[0067] Step 3: Perform phase compensation on the currently calculated cross-correlation results using the phase compensation value; whereby the phase compensation value... Derived from step 6, the initial value is When performing compensation, based on the peak detection position Pidx, compensation is only applied to the peak position of the cross-correlation result and the two points before and after the peak. The specific method is as follows:

[0068] When idx≥Pidx-1&&idx≤Pidx+1

[0069]

[0070] otherwise

[0071] S(idx)=S′ C (idx)

[0072] S is related to S' CThe corresponding value after phase compensation, Here, idx is the phase compensation value, and idx is the data index value of the cross-correlation result within one symbol, ranging from 0 to N. smp -1;

[0073] Step 4: Add the cross-correlation result after phase compensation to the cross-correlation result of the previous symbol at the same position; for example... Figure 2 As shown, the cross-correlation result S(idx) after phase compensation is compared with the cross-correlation result S″ of the previous symbol. C (idx) performs addition of the same positions within the symbol. The addition method is as follows:

[0074] When C peak When = 0,

[0075] S Add (idx)=abs(S(idx))+abs(S″ C (idx))

[0076] When C peak >0

[0077] S Add (idx)=abs(S(idx)+S″ C (idx))

[0078] Among them, S Add The result is the sum of the cross-correlation results of the two symbols at the same position, where idx is the data index of the cross-correlation result in a symbol, and C is the result of the cross-correlation results at the same position. peak To update the peak period detection count value, abs() performs the absolute value operation, S' C S″ represents the cross-correlation result of the current symbol. C S is the cross-correlation result of the previous symbol, and S' is the result of the cross-correlation with S'. C The corresponding value after phase compensation;

[0079] Step 5: Use the summed cross-correlation results to perform peak period detection, and update the peak detection position and peak period detection count value;

[0080] Step 6: Update the phase compensation value based on the peak period detection count and the calculated phase difference; the specific process is as follows:

[0081] S601, Determine the peak period detection count value C peak Is it 0?

[0082] S602, when the peak period detection count value C peak When = 0, the output phase compensation value is

[0083] S603, When the peak period detection count value C peak When ≠0, continue with C. peak Is it less than C'? peak ;

[0084] S604, When the peak period detection count value C peak <C' peak If the output phase compensation value is not updated, then

[0085] S605, When the peak period detection count value C peak ≥C' peak Continue to judge C. peak Is it equal to 1?

[0086] S606, When the peak period detection count value C peak When = 1, the output phase compensation value is

[0087] S607. Otherwise, update the phase compensation value.

[0088] in, The phase compensation value before the update; C' peak The peak period detection count value before the update; The phase difference is calculated.

[0089] Step 7: Determine whether the peak period detection count value has reached the set threshold. If it has reached the set threshold, output the signal detection result; if it has not reached the threshold, repeat steps 1-7.

[0090] Therefore, this invention employs the aforementioned frequency offset self-compensation UWB signal detection method, which estimates the carrier frequency offset simultaneously with signal detection. The estimated carrier frequency offset is used to perform phase compensation on points near the peak of the current cross-correlation result, and the phase-compensated cross-correlation result is added to the cross-correlation result of the previous symbol, thus enhancing the cross-correlation result. Furthermore, the enhanced cross-correlation result is further enhanced through cumulative filtering. This method improves the sensitivity of signal detection while maintaining low complexity.

[0091] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A UWB signal detection method with frequency offset self-compensation, characterized in that, Includes the following steps: Step 1: Perform cross-correlation calculation on the ADC-sampled signal and the local sequence; Step 2: Based on the peak detection position, calculate the phase difference using the calculated cross-correlation result and the cross-correlation result of the previous symbol; Step 3: Perform phase compensation on the current cross-correlation calculation results using the phase compensation value; Step 4: Add the cross-correlation result after phase compensation to the cross-correlation result of the previous symbol at the same position; Step 5: Use the cross-correlation result after addition to perform peak period detection, and update the peak detection position and peak period detection count value; Step 6: Update the phase compensation value based on the peak period detection count value and the calculated phase difference; Step 7: Determine whether the peak period detection count value has reached the set threshold. If it has reached the set threshold, output the signal detection result; if it has not reached the threshold, repeat steps 1-7. The calculation expression for the cross-correlation operation in step 1 is as follows: Among them, S C For the result of cross-correlation calculation, s sig S is the signal sampled by the ADC. loc For local sequences, N smp The number of sampling points contained in one symbol period; In step 2, based on the peak detection position, the phase difference is calculated using the calculated cross-correlation result and the cross-correlation result calculated for the previous symbol, including the following cases: When Pidx < 0 When Pidx = 0, the calculation method is as follows: When 0 <Pidx<N smp When the value is -1, the calculation method is as follows: When Pidx = N smp When the value is -1, the calculation method is as follows: in, For calculating the phase difference, angle() is the method to convert a complex number to radians, conj() is the method to take the conjugate, Pidx is the index of the current peak detection position, and S' C S represents the result of the cross-correlation operation of the current symbol. C N is the result of the cross-correlation operation of the previous symbol. smp The number of sampling points contained in one symbol period.

2. The UWB signal detection method with frequency offset self-compensation according to claim 1, characterized in that, The specific process of performing phase compensation on the currently calculated cross-correlation result using the phase compensation value in step 3 is as follows: When idx≥Pidx-1&&idx≤Pidx+1 otherwise S(idx)=S' C (idx) S is related to S' C The corresponding value after phase compensation, Here, idx is the phase compensation value, and idx is the data index value of the cross-correlation operation result within one symbol, with a value range of 0 to N. smp -1.

3. The UWB signal detection method with frequency offset self-compensation according to claim 2, characterized in that, The specific expression for adding the cross-correlation result after phase compensation in step 4 to the cross-correlation result of the previous symbol at the same position is as follows: When C peak When = 0, S Add (idx)=abs(S(idx))+abs(S” C (idx)) When C peak >0 S Add (idx)=abs(S(idx)+S” C (idx)) Among them, S Add The result is the sum of the cross-correlation results of two symbols at the same position, where idx is the data index of the cross-correlation result in a symbol, and C is the result of the cross-correlation operation. peak To update the peak period detection count value, abs() performs the absolute value operation, S' C S represents the result of the cross-correlation operation of the current symbol. C S is the result of the cross-correlation operation of the previous symbol, and S' is the result of the cross-correlation operation of the previous symbol. C The corresponding value after phase compensation.

4. The UWB signal detection method with frequency offset self-compensation according to claim 3, characterized in that, The specific process of updating the phase compensation value in step 6 based on the peak period detection count value and the calculated phase difference is as follows: S601, Determine the peak period detection count value C peak Is it 0? S602, when the peak period detection count value C peak When = 0, the output phase compensation value is S603, when the peak period detection count value C peak If ≠0, continue to evaluate C. peak Is it less than C'? peak ; S604, When the peak period detection count value C peak <C' peak If the output phase compensation value is not updated, then S605, When the peak period detection count value C peak ≥C' peak Continue to judge C. peak Is it equal to 1? S606, When the peak period detection count value C peak When = 1, the output phase compensation value is S607. Otherwise, update the phase compensation value. in, The phase compensation value before the update; C' peak The peak period detection count value before the update; The phase difference is calculated.

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