WO2011137631A1

WO2011137631A1 - Method and apparatus for detecting ranging code

Info

Publication number: WO2011137631A1
Application number: PCT/CN2010/077739
Authority: WO
Inventors: 李春明; 韩杨
Original assignee: 中兴通讯股份有限公司
Priority date: 2010-05-04
Filing date: 2010-10-14
Publication date: 2011-11-10
Also published as: CN102238123A; CN102238123B

Abstract

A method for detecting ranging code is provided by the present invention，which includes: performing a Fast Fourier Transform (FFT) for the received time domain signal, obtaining the ranging signal from the ranging subcarrier of the frequency domain signal which is obtained after the transformation, wherein, the ranging signal is composed of at least two symbols in the time domain; performing phase compensation and weighted combination for the sequence of the symbols except for the first symbol, and obtaining the combined sequence; selecting the local codes in turn from the stored code list, performing correlation operation, difference operation and FFT with the selected local code sequence and the combined sequence, calculating the power of the sequence generated after the FFT, and obtaining the Peak-to-Mean Ratio of the sequence; when the Peak-to-Mean Ratio is higher than a first threshold, determining that the received time domain signal carries the ranging code. Other Apparatus and methods for detecting ranging code are also provided by the present invention. Application of the present invention can improve the detection ratio of the ranging code.

Description

Ranging code detection method and device

The present invention relates to the field of mobile broadband wireless, and in particular, to a method and device for detecting a ranging code. Background technique

IEEE (Institute of Electrical and Electronics Engineers) 802.16e is a standard for mobile broadband wireless access systems based on OFDMA (Orthogonal Frequency Division Multiplexing Access) technology. Ranging is a process used in the 802.16e protocol to adjust the mobile subscriber carrier frequency offset, timing offset, and received power in an OFDMA system.

Generally, the base station specifies a time-frequency resource block for the mobile user to perform ranging, and the resource block is called a ranging region. The 802.16e protocol specifies four ranging methods. The base station specifies a corresponding ranging code for different ranging methods. The ranging code is a CDMA (Code Division Multiple Access) code. .

When the initial ranging is performed, the mobile user selects a ranging code from the code table specified by the base station to be transmitted on the specified ranging area, and is used to complete system parameter estimation and adjustment of the uplink ranging process. The base station detects the ranging code sent by the mobile user from the received ranging signal and calculates information such as time offset and frequency offset, and then feeds back to the mobile user transmitting the ranging code. The mobile user then adjusts his own transmission parameters based on this information.

At present, the detection method of the ranging code is mainly based on the autocorrelation property of the ranging code, and can be divided into a time domain correlation method and a frequency domain correlation method. The former means that the base station does not do the time domain data received.

FFT (Fast Fourier Transform), which directly correlates with the local code and detects the peak value; the latter refers to the FFT of the received time domain data after the base station transforms the value on the ranging subchannel and the local code. Perform correlation operations, IFFT (Inverse Fast Fourier Transform, Fast Fourier Transform) and other operations.

In practical practice, the time domain correlation method is rarely used because of the large amount of computation and the vulnerability of data users. The idea of frequency domain correlation method is simple, the implementation is simple, and the introduction of IFFT operation makes the calculation amount much less than the time domain correlation method. Therefore, it is usually used to detect the distance measurement code.

There are generally two indicators for measuring the performance of the ranging detection algorithm: detection rate and false alarm rate. The false alarm rate is the probability of detecting a ranging code that the user has not sent. With the application of various advanced technologies such as MIMO (Multi-Input Multiple-Output) and beamforming technology, the performance indicators such as downlink coverage and throughput of the base station have been greatly improved, and the system works normally. The sensitivity (ie, signal to noise ratio) is further reduced. However, the frequency domain correlation method has a very low detection rate at low SNR, which makes the system performance limited by the uplink initial ranging code access detection. At present, most of the range detection methods used only consider application scenarios where the signal-to-noise ratio is above OdB. For the case where the signal-to-noise ratio is much lower than OdB, the performance is not satisfactory at low SNR. In addition, many ranging detection methods are derived under the AWGN (Additive White Gaussian Noise) channel. In actual application environments, the channels are mostly multipath fading channels, which do not match the detection method environment. , will lead to a further decline in the detection rate of the ranging code. Summary of the invention

The embodiment of the present invention provides a method for detecting a ranging code, which is used to solve the problem that the detection rate of the ranging code detection method proposed in the prior art is extremely low at a low SNR, so that the system performance is limited by the initial ranging of the uplink. Code access detection issues, including:

Performing a fast Fourier transform FFT on the time domain signal received by the single antenna, and acquiring a ranging signal on the ranging subcarrier of the frequency domain signal obtained after the transform;

Phase compensation is performed on sequences of other symbols except the first symbol, and the compensation value is an equivalent phase delay of the cyclic prefix CP length; The sequence of the first symbol and the sequence obtained by phase compensation of each of the other symbols are weighted and combined to obtain a combined sequence, wherein the weighted weight is between [0, 1], and the sum of the weights is equal to 1 . And proportional to the amount of data information carried on each symbol;

Selecting a local code in the stored code table, and performing a correlation operation using the sequence of the selected local code and the merged sequence;

Performing a differential operation and an FFT on the sequence obtained after the correlation operation, and calculating the power of each value in the sequence generated by the differential operation and the transformation;

Determining a peak-to-average ratio according to the power of each value in the sequence generated by the differential operation and the transformation; when the peak-to-average ratio is greater than the first threshold, determining that the received time domain signal carries a ranging code, the first gate The limit is not less than the threshold corresponding to the upper limit of the preset range detection rate.

The embodiment of the present invention further provides a method for detecting a ranging code, which is used to solve the problem that the detection method of the ranging code detection method proposed in the prior art has a very low detection rate at a low SNR, so that the system performance is limited by the initial measurement of the uplink. The problem of code access detection includes:

When a plurality of time domain signals are received via multiple antennas, each of the time domain signals is separately operated to obtain a sequence generated by the differential operation: performing a fast Fourier transform FFT on the time domain signal, and obtaining a frequency domain signal after the transform. Obtaining a ranging signal on the ranging subcarrier; performing phase compensation on the sequences of other symbols except the first symbol, the compensation value is an equivalent phase delay of the cyclic prefix CP length; the sequence of the first symbol and other The sequences obtained by phase compensation of each symbol are weighted and combined to obtain a combined sequence, wherein the weighted weights are located between [0, 1], the sum of the weights is equal to 1, and the data information carried on each symbol The quantity is proportional; the local code is sequentially selected in the stored code table, the correlation operation is performed by using the sequence of the selected local code and the combined sequence, and the sequence obtained after the correlation operation is differentially operated;

Combining the obtained sequence values of the plurality of sequences generated by the differential operation to obtain the added sequence, and performing FFT;

Calculating the power-determined peak-to-average ratio of the sequence obtained by the FFT transformation; When the peak-to-average ratio is greater than the first threshold, it is determined that the received time domain signal carries a ranging code, and the first threshold is not less than a threshold corresponding to the upper limit of the preset ranging code detection rate.

The embodiment of the present invention further provides a ranging code detecting device, which is used to solve the problem that the detection rate of the ranging code detecting method proposed in the prior art is extremely low at a low SNR, so that the system performance is limited by the initial measurement of the uplink. The problem of code access detection includes:

a compensation module, configured to perform fast Fourier transform FFT on the time domain signal received by the single antenna, and obtain a ranging signal on the ranging subcarrier of the frequency domain signal obtained after the transform; and other symbols except the first symbol The sequence is separately phase compensated, and the compensation value is an equivalent phase delay of the cyclic prefix CP length;

a weighting module, configured to weight combine the sequence of the first symbol and the sequence obtained by phase compensation of the other symbols to obtain a combined sequence, wherein the weighted weight is between [0, 1], each weight The sum is equal to 1 and is proportional to the amount of data carried on each symbol;

a calculation module, configured to sequentially select a local code in the stored code table, perform a correlation operation by using the selected local code sequence and the merged sequence; perform differential operation and FFT on the sequence obtained after the correlation operation, and calculate the difference The power of each value in the sequence generated after operation and transformation; calculating the peak-to-average ratio of the power of the sequence obtained by the FFT transformation;

a first determining module, configured to: when the peak-to-average ratio is greater than the first threshold, determine that the received time domain signal carries a ranging code, where the first threshold is not less than a preset detection rate upper limit Corresponding threshold.

The embodiment of the present invention provides a ranging code detecting apparatus, which is used to solve the problem that the detection method of the ranging code method proposed in the prior art has a very low detection rate at a low SNR, so that the system performance is limited by the uplink initial ranging code. Access detection issues, including:

Obtaining a module, when used for multiple time domain signals received via multiple antennas, respectively performing the following operations for each time domain signal to obtain a sequence generated by the differential operation: performing fast Fourier transform FFT on the time domain signal, after the transform Obtaining a ranging signal on the ranging subcarrier of the obtained frequency domain signal; Phase compensation is performed on sequences of symbols other than the first symbol, and the compensation value is an equivalent phase delay of the cyclic prefix CP length; the sequence of the first symbol and the sequence obtained by phase compensation of other symbols are weighted. Merging, obtaining a merged sequence, wherein the weighted weights are between [0, 1], the sum of the weights is equal to 1, and is proportional to the amount of data information carried on each symbol; in the stored code table Selecting a local code in turn, performing a correlation operation on the sequence of the selected local code and the merged sequence, and performing a differential operation on the sequence obtained after the correlation operation;

The adding module is configured to add the sequence values of the obtained sequence generated by the difference operation to obtain the added sequence, and perform FFT; calculate the power determining peak of the sequence obtained by the FFT transform Ratio

a third determining module, configured to: when the peak-to-average ratio is greater than the first threshold, determine that the received time domain signal carries a ranging code, where the first threshold is not less than a preset detection rate upper limit Corresponding threshold.

The method and the device provided by the embodiments of the present invention add and combine two or more symbols included in the ranging signal in the frequency domain, thereby improving the signal to noise ratio, thereby solving the low signal to noise ratio mentioned in the background art. As a result, the detection rate of the ranging code is low, so that the system is limited by the problem of the uplink initial ranging code access detection, and the performance of the system is improved. DRAWINGS

1 is a flowchart of a first method for detecting a ranging code according to an embodiment of the present invention; a flowchart of a first method for determining a rate;

3 is a flowchart of a method for detecting a second ranging code according to an embodiment of the present invention; a flowchart of a second method for determining a rate;

FIG. 5 is a specific flowchart of a method for detecting a ranging code according to an embodiment of the present invention;

FIG. 6 is a schematic diagram of a first structure of a first ranging code detecting apparatus according to an embodiment of the present invention; Figure

FIG. 7 is a schematic structural diagram of a computing module according to an embodiment of the present disclosure;

FIG. 8 is a schematic diagram of a second structure of a first ranging code detecting apparatus according to an embodiment of the present invention; FIG.

FIG. 9 is a schematic diagram of a first structure of a second ranging code detecting apparatus according to an embodiment of the present invention; FIG.

FIG. 10 is a schematic structural diagram of an obtaining module according to an embodiment of the present disclosure;

FIG. 11 is a schematic structural diagram of an adding module according to an embodiment of the present disclosure;

FIG. 12 is a schematic diagram showing a second structure of a second ranging code detecting apparatus according to an embodiment of the present invention. detailed description

In order to solve the problem that the frequency domain correlation method has a very low detection rate at a low SNR, the system performance is limited by the uplink initial ranging code access detection. The embodiment of the present invention provides two ranging code detection methods. One application scenario suitable for receiving signals by using a single antenna, and another application scenario for receiving signals by using multiple antennas.

To solve the above technical problem, the first method for detecting a ranging code provided by the embodiment of the present invention is applicable to an application scenario in which a signal is received by using a single antenna. The specific processing flow is shown in FIG. 1 , and the method includes:

Step 101: Acquire a ranging signal.

Specifically, the fast Fourier transform FFT is performed on the time domain signal received by the single antenna, and the ranging signal is obtained on the ranging subcarrier of the frequency domain signal obtained after the transform, and the ranging signal is composed of at least two symbols in the time domain. .

Step 102: Perform phase compensation.

Specifically, the sequences of the symbols other than the first symbol are respectively phase-compensated, and the compensation value is an equivalent phase delay of the length of the CP (Cyclic Prefix). Step 103: Perform weighted combining.

Specifically, the sequence of the first symbol and the sequence obtained by phase compensation of each of the other symbols are weighted and combined to obtain a combined sequence.

Wherein, the weighted weight is between [0, 1], and the sum of the weights is equal to 1 and is proportional to the amount of data information carried on each symbol.

Step 104: Perform correlation operations, differential operations, and FFTs.

Specifically, the local code is sequentially selected in the stored code table, and the correlation operation is performed by using the sequence of the selected local code and the merged sequence.

Perform differential operation and FFT on the sequence obtained after the correlation operation, and calculate the power of each value in the sequence generated after the differential operation and transformation.

Step 105: Determine a peak-to-average ratio.

Specifically, the peak-to-average ratio is determined according to the power of each value in the sequence generated by the differential operation and the FFT transformation, and the peak-to-average ratio is the ratio of the peak power to the mean power of each value of the sequence generated by the differential operation and the transformation.

Step 106: When the peak-to-average ratio is greater than the first threshold, determine that the received time domain signal carries the ranging code.

Specifically, when the peak-to-average ratio is greater than the first threshold, it is determined that the received time domain signal carries a ranging code, and the first threshold is not less than a threshold corresponding to the upper limit of the preset ranging code detection rate.

Step 101 In implementation, the ranging signal is composed of at least two symbols in the time domain, wherein, from the perspective of the time domain, the other symbols located after the first symbol are copies of the first symbol; From the perspective of the domain, the subcarriers occupied by the symbols in the frequency domain are identical. Therefore, the process in which the ranging signal is affected by independent Gaussian white noise after passing through the channel can be regarded as the same signal undergoing two different interferences. According to the theory of random digital signal processing, the signal-to-noise ratio after adding and combining the signals of different white noise interferences is S times, and S is a positive integer. Therefore, for the ranging signal, two or more symbols are added and combined in the frequency domain, and the ranging signal pair can be The signal-to-noise ratio should be more than doubled. For example, when the ranging signal includes two symbols, adding and combining two symbols in the frequency domain can increase the signal-to-noise ratio by a factor of about 3 dB. The CP of other symbols except the first symbol needs to be added at the end of the symbol. For other symbols, the phase deflection in the frequency domain is brought about. Therefore, it is not possible to directly add more than two symbols. The problem is that, when the step 102 is implemented, the embodiment of the present invention proposes a phase compensation method with a length of CP for each symbol, and the specific processing manner is as follows: According to the formula Υ; _Λ = Υ _ί * xp (-j^k) for each other The sequence of symbols is phase compensated separately, where i, j, and k are positive integers, i > 2, where N is the FFT window value, indicating the frequency domain value of the kth subcarrier of the ith symbol, indicating the ith symbol Phase exp (- / ^iL k) of the kth subcarrier

The compensated frequency domain value, ^ is the CP length, N is the equivalent phase delay of cp length, exp (- / ^iL k)

In other words, the compensation value is N .

In the process of ranging signal transmission, considering that the ranging signal arrives at the receiving end, there will be a delay of a certain time, and the information carried on the first symbol may be reduced. Therefore, two or more symbols may be separately set. Value, each symbol is multiplied by the corresponding weight and then added. As mentioned in step 103, the weighted weight is proportional to the amount of data information carried on each symbol. In the implementation, in order to ensure the accuracy of the frequency domain sequence obtained after the weighted combination, the weighted weight may be further defined. For example, the weighted weight may be further defined according to the coverage radius of the cell, and each weight is defined. It is proportional to the coverage radius of the small cell in which it is located. Of course, in implementation, the weighted weights can also be defined according to other cell environments or conditions, and the accuracy of the sequence obtained after the weighted combination can be increased.

In order to clarify and more clearly illustrate the method of weighted merging using weights, the two existing symbols are described as an example, and one weight is set for each of the two symbols according to the proportion of the amount of data information carried on the two symbols. The obtained merged expression is as follows: ^ ' ^ + ' i^ , where Y _k represents the sequence obtained by combining the two symbols.

According to the method provided by the embodiment of the present invention, adding and combining two or more symbols included in the ranging signal in the frequency domain can improve the signal-to-noise ratio, and further can solve the ranging caused by the low signal-to-noise ratio mentioned in the background art. The code detection rate is low, so that the system is limited by the problem of uplink initial ranging code access detection, and the performance of the system is improved.

In the process shown in FIG. 1, the step 104 is performed in a differential operation and an FFT. The embodiment of the present invention provides a preferred implementation manner. The specific process is shown in FIG. 2:

Step 201: Map the correlated frequency domain sequence to the ranging subcarrier.

Step 202: Perform differential operations on the sequence carried on the ranging subcarriers in sequence.

Specifically, the sequence carried on the ranging subcarriers with the distance ^Δ / is differentially operated according to the following formula to obtain a sequence of length Μ: η] = ∑ c _k Y _k H _k χρ(- Ά ₀ ) * ( c _k+n Y _k+n H _k+n exp(~ ² + ") /.))*

V V

= ∑ H _t Hl _{n QV} (j^n)

V where l≤n≤M, n, M is a positive integer, M is the maximum interval of subcarriers, Δ/ is the interval between two adjacent subcarriers, K represents the set of all ranging subcarriers, H _k and H _k+n is the channel correlation coefficient, and C _k and C _k+n are sequences corresponding to the local code C, 1. Is the time offset of the received time domain signal, and N is the value of the system FFT window size.

Step 203: Perform zero-padding and fast Fourier transform.

Specifically, after the differential operation, the sequence of length M is complemented by N _t -M 0s, and the sequence of length N _t formed after zero padding is subjected to FFT, where N _t is located at [N/8, N Between, and N _t is progressive by a power of two.

In step 203, when the local code is a ranging code sent by the user, the sequence obtained after the FFT operation is a quasi-function waveform, and the peak is located at the position of the user. In the process of detecting and determining the ranging code, the channel coefficient also has a certain influence on the detection rate. If the channel coefficient is too large, the detection rate is also greatly reduced. To solve the problem, the present invention is implemented. The example provides a solution by utilizing the characteristics in the coherent bandwidth. The characteristics are as follows: When the two subcarriers participating in the differential operation should be located within the coherence bandwidth of the channel, the influence of the channel coefficients can be eliminated by the differential operation between the subcarriers. The solution is as follows: Take two subcarriers with subcarrier spacing less than the coherent bandwidth for differential operation. At this time, it can be approximated as the same channel coefficient, that is, H _k = H _k+n . After differential operation, it can be obtained: xWK^ Exp ^^) , where,

N

Is the number of carrier pairs with a spacing of " ^Δ " in the ranging subcarrier set K, and Δ/ is the subcarrier spacing specified by the 802.16e protocol.

The subcarriers with the interval smaller than the coherent bandwidth are calculated, and compared with the fading multiplication of the subcarriers with only the interval of 1 to eliminate the fading effect of the channel, better performance can be obtained with a small amount of calculation.

As shown in FIG. 1 , in step 106, according to the comparison result between the peak-to-average ratio and the first threshold, whether the ranging code is included in the time domain signal is included in the background signal, and the performance of the ranging detection algorithm is generally measured. There are two indicators, detection rate and false alarm rate. However, in the existing ranging code detection method, the detection rate is proportional to the false alarm rate, the detection rate is high, and the corresponding false alarm rate is also increased, and the detection rate is improved. If the alarm rate is low, the corresponding threshold rate is reduced, and a low false alarm rate cannot be obtained while ensuring a high detection rate. To solve the problem, the embodiment of the present invention proposes to determine the first threshold value and the second threshold value. The method of the ranging code is as follows: After confirming that the peak-to-average ratio is greater than the first threshold, determining that the received time-domain signal carries the ranging code, determining that the peak-to-peak ratio is greater than the second threshold, wherein, the peak The peak ratio is the ratio of the peak power of each value of the sequence generated by the differential operation and the conversion to the mean value of the peak power corresponding to each local code, and the second threshold is not less than the gate corresponding to the lower limit of the preset ranging code alarm rate. Value.

In implementation, the first threshold value depends on the signal-to-noise ratio and the specific channel environment. Preferably, the first threshold value ranges from [12, 16], usually, in [12, 16]. Can be used when taking values Enough to ensure a high detection rate.

In addition, the second threshold value also depends on the signal-to-noise ratio and the specific channel environment. Preferably, the second threshold value ranges from [3, 6], and is usually taken in [3, 6]. A low false alarm rate can be guaranteed for the value.

The method of determining the ranging code by combining the first threshold value and the second threshold value overcomes the contradiction between the detection rate and the false alarm rate caused by simply relying on the peak-to-average ratio detection ranging code, and can improve the detection. The rate is guaranteed to achieve a lower false alarm rate.

In implementation, in addition to the method of determining the ranging code by combining the first threshold value and the second threshold value, that is, the method of determining the ranging code by using the peak-to-average ratio and the peak-to-peak ratio, there may be other methods for determining the ranging code. It is possible to increase the detection rate while ensuring a low false alarm rate.

In order to solve the above technical problem, the second method for detecting a distance detection code provided by the embodiment of the present invention is applicable to an application scenario in which a signal is received by using multiple antennas. The specific processing flow is as shown in FIG. 3, and includes: Step 301: Receiving through multiple antennas When multiple time domain signals are used, the following operations are performed on each of the time domain signals to obtain a sequence generated by the differential operation; specifically, the fast Fourier transform FFT is performed on the time domain signal, and the frequency domain signal obtained after the transform is obtained. Obtaining a ranging signal on the ranging subcarrier, the ranging signal is composed of at least two symbols in the time domain; phase compensation is performed on sequences of other symbols except the first symbol, and the compensation value is a cyclic prefix CP length, etc. Effect phase delay; weighting and merging the sequence of the first symbol and the sequence obtained by phase compensation of other symbols to obtain a combined sequence, wherein the weighted weight is between [0, 1], and each weight And equal to 1, and is proportional to the amount of data information carried on each symbol; select the local code in turn in the stored code table, using the selection The combined sequence of the local code sequences with correlation operation, the correlation operation and differential operation sequence obtained.

Step 302: Add the sequence values of the obtained plurality of sequence operations generated by the difference operation to obtain the added sequence, and perform FFT.

Step 303: Calculate the power of the sequence obtained by the FFT transformation, and determine a peak-to-average ratio. The peak-to-average ratio is the ratio of the peak power to the mean power of each value of the sequence generated after the differential operation and transformation.

Step 304: When the peak-to-average ratio is greater than the first threshold, determine that the received time domain signal carries a ranging code, and the first threshold is not less than a threshold corresponding to the upper limit of the preset ranging code detection rate.

Step 301: When implemented, the ranging signal is composed of at least two symbols in the time domain, wherein, from the perspective of the time domain, the other symbols located after the first symbol are copies of the first symbol; From the perspective of the domain, the subcarriers occupied by the symbols in the frequency domain are identical.

For the ranging symbol, the CP of the second symbol is added at the end of the symbol, so the phase deflection in the frequency domain is brought about relative to the first symbol. Therefore, the two symbols cannot be directly added. To solve the problem, refer to step 301. The embodiment of the present invention proposes a phase compensation method with a length of CP for each symbol, and the specific processing manner is as follows: According to the formula 1^ = Υ _ί * _cxp (-j^k) for other symbols The sequence is separately compensated, wherein i, j, k are positive integers, i > 2, N is the FFT window value, indicating the frequency domain value of the kth subcarrier of the ith symbol, indicating the ith symbol Phase exp(k / - · ^iL k) of the kth subcarrier

The compensated frequency domain value, ^ is the CP length, N is the equivalent phase delay of cp length, exp(— /· ^iL k)

In other words, the compensation value is N .

In the process of ranging signal transmission, considering that the ranging signal arrives at the receiving end, there will be a delay of a certain time, and the information carried on the first symbol may be reduced. Therefore, two or more symbols may be separately set. Value, each symbol is multiplied by the corresponding weight and then added. As mentioned in step 103, the weighted weight is proportional to the amount of data information carried on each symbol. In the implementation, in order to ensure the accuracy of the frequency domain sequence obtained after the weighted combination, the weighted weight may be further defined. For example, the weighted weight may be further defined according to the coverage radius of the cell, and each weight is defined. It is proportional to the coverage radius of the small cell in which it is located. Of course, when implemented, weighted The weight can also be defined according to other community environments or conditions, and the accuracy of the sequence obtained by weighted combination can be increased.

In order to clarify and more clearly illustrate the method of weighted merging using weights, two symbols are taken as an example for illustration, and one weight is given to each of the two symbols according to the proportion of the amount of data information carried on the two symbols.

The obtained combination is as follows: Ί + ' ¹ ^ , where Y _k represents the frequency domain sequence obtained by combining the two symbols.

In the process shown in FIG. 3, in step 301 and step 302, the mapped ranging subcarriers are differentially operated, and the sequence values on the plurality of antennas generated by the differential operation are added to obtain the added values. The sequence determines the corresponding power of each point in the added sequence, and calculates the peak-to-average ratio. The specific processing manner is as shown in FIG. 4, including:

Step 401: Map the sequence obtained after the correlation operation to the corresponding ranging subcarrier.

Step 402: Perform differential operations on the sequence carried on the ranging subcarriers in sequence.

Specifically, the sequence carried on the ranging subcarriers with a distance of " ^Δ / is sequentially subjected to a differential operation according to the following formula to obtain a sequence of length Μ:

4η] = ∑ c _k Y _k H _k χρ(- Ά ₀ ) * (c _k+n Y _k+n H _k+n exp(~ ² + ") /.))*

V V

Where l≤n≤M, n, M are positive integers, M is the maximum interval of subcarriers, Δ/ is the interval between two adjacent subcarriers, and K is the set of all ranging subcarriers, H _k and H _k+n is the channel correlation coefficient, C _k and C _k+n are the sequences corresponding to the local code C, and lo is the time domain signal of the received time domain. N is the system FFT window size.

Step 403: Perform an adding operation.

Specifically, the differential post-sequences of the plurality of antennas generated by the differential operation are correspondingly added to obtain an added sequence of length M;

Step 404, zero padding and performing fast Fourier transform.

In step 403, when the local code is the ranging code sent by the user, the sequence obtained by the FFT operation is a quasi-function waveform, and the peak is located at the time of the user.

In the implementation of step 402, the sequence of multiple antennas generated by the differential operation is correspondingly added to obtain an added frequency-sequence sequence of length M, which is avoided as mentioned in other ranging code detection methods. Each antenna data is subjected to an FFT operation (or IFFT operation), which can greatly reduce the amount of calculation and save resources.

In the process of detecting and determining the ranging code, the channel coefficient also has a certain influence on the detection rate. If the channel coefficient is too large, the detection rate is also greatly reduced. To solve the problem, the present invention is implemented. The example provides a solution by utilizing the characteristics in the coherent bandwidth. The characteristics are as follows: When the two subcarriers participating in the differential operation should be located within the coherence bandwidth of the channel, the influence of the channel coefficients can be eliminated by the differential operation between the subcarriers. The solution is as follows: Take two subcarriers with subcarrier spacing less than the coherent bandwidth for differential operation. In this case, it can be approximated as channel affinity, ^Ρ 3⁄4 = _3⁄4+η , jump "^"), medium, is measured The number of carrier pairs with a spacing of " ^Δ /" from the set of subcarriers K, Δ / is the subcarrier spacing specified by the 802.16e protocol.

The subcarriers with the interval smaller than the coherent bandwidth are calculated, and compared with the fading multiplication of the subcarriers with only the interval of 1 to eliminate the fading effect of the channel, the calculation can be better with a small amount of calculation. Performance.

As shown in FIG. 3, in step 304, according to the comparison result between the peak-to-average ratio and the first threshold, whether the ranging code is included in the time domain signal is included, as mentioned in the background art, the performance of the ranging detection algorithm is generally measured. There are two indicators, detection rate and false alarm rate. However, in the existing ranging code detection method, the detection rate is proportional to the false alarm rate, the detection rate is high, and the corresponding false alarm rate is also increased, and the detection rate is improved. If the problem is low, the corresponding false alarm rate is also reduced, and a low false alarm rate cannot be obtained while ensuring a high detection rate. To solve the problem, the embodiment of the present invention proposes combining the first threshold and the second threshold. The method for determining the ranging code is as follows: After confirming that the peak-to-average ratio is greater than the first threshold, determining that the received time-domain signal carries the ranging code, determining that the peak-to-peak ratio is greater than the second threshold, where The peak-to-peak ratio is the ratio of the peak power of each value of the sequence generated by the differential operation and the conversion to the mean value of the peak power corresponding to each local code, and the second threshold is not less than the corresponding lower limit of the preset ranging code alarm rate. door Value.

In implementation, the first threshold value depends on the signal-to-noise ratio and the specific channel environment. Preferably, the first threshold value ranges from [12, 16], usually, in [12, 16]. A high detection rate can be ensured when the value is taken.

Now, a specific embodiment will be described. In this example, the 4 antenna is received, and the 10M system is used. For example, in the implementation, four time domain signals can be synchronously received, and the ranging subcarriers occupy 144 of all 1024 subcarriers, and each ranging signal includes two symbols, respectively, symbol 1, symbol 2, CP. The length of the system is 1024. The size of the system FFT window is 1024. The number of local codes stored in the code table is 64. For details, see Figure 5, including:

Step 501: Each antenna receives the time domain signal, and transforms to the frequency domain by FFT, and completes phase compensation of symbol 2 and weighted combining processing with symbol 1.

Step 502: Take a local code to perform a correlation operation; specifically, take a local code 0 „( 0 ≤ <64 ),

C _m = ( ^C TM,0, ,l, ,143) _^ ^ ^ Perform correlation operations to obtain the relevant sequence 歹|J

Perform differential operation and perform multi-antenna combining; perform FFT transformation on the combined difference sequence, calculate the sequence power, and find the power peak and the mean.

Step 503: Perform a determination of the ranging code according to the power peak value and the average value, and obtain a time offset.

Specifically, when the step 501 is implemented, the method specifically includes:

The received time domain data is transformed into the frequency domain by FFT to obtain frequency domain data;

The data on theranging subcarrier is extracted from the frequency domain data to obtain the ranging frequency domain data, which is represented by ^Y "' ^k , where i, j, k respectively represent the receiving antenna sequence number, the ranging symbol sequence number, and the ranging subcarrier physical sequence number; partial compensation data of the second ranging symbol ^Y2 ^'k accordance ^{= ^' ^ + "2 ·} Υ for 128 points, a partial compensation sequence ^{^represented:} ¼ί = ¼ί ^'7 ^;

Multiply ^ by the symbol 2 weight "2, plus the symbol 1 frequency domain data w multiplied by the symbol 1 weight ^α ι , to get a new sequence ^ , , ^ + ^ ¹ ^.

Specifically, when the step 502 is implemented, the method specifically includes: performing differential operation processing on the sequence in which the local code C _m and the ^Yi ' ^k are related to each other, that is,

〉 d, d Where 1 ≤ " ≤ M, M is the maximum number of subcarriers of the conjugate difference, and according to the channel condition setting, a sequence of data length M can be obtained by the above operation;

The four receiving antenna data are processed according to the above steps, and four sequences of length M are obtained;

The four sequences are combined to obtain a sequence of length M and complemented by 0 to N _t , N _t = 256, and the sequence ^{Z ≤} "^{< 256 is obtained} . The combined formula is as follows:

Perform a 256-point FFT on ² " to obtain a transformed sequence, calculate the power of the sequence, and find the average power, store it in the mean memory; find its power peak and its position pos _m , and store it at the peak. In memory and in peak position memory;

The above operation is performed for all the local codes C to obtain 64 P _avg , and pos _m .

Specifically, when the step 503 is implemented, the method specifically includes:

For the current candidate code C _m , take out its peak power and mean power, and calculate the peak.

Ρ

PAPR ― ^m,peak

Equivalent to E4PR _m : ^P ; Take out the peak values of all other codes in this frame, and find the mean of these peaks ^ * ;

Cm peak dead _m, "is divided by" ratio of peak obtained p _T P _m, the formula is calculated as follows: p = a p

0<κ<63

ρ

m ― ― Use / R^ to compare with the first threshold TH1, corpse: TP _{m is} compared with the second threshold TH2. If PAPR _m >jm and PTP^Tm, the candidate code is regarded as the measurement sent by the user. Distance code, go to the next One-step processing; otherwise, the next local code is processed directly.

Based on the same inventive concept, an embodiment of the present invention further provides a ranging code detecting device. The specific structure is as shown in FIG. 6, and includes:

a compensation module 601, configured to perform fast Fourier transform on a time domain signal received through a single antenna

FFT, acquiring a ranging signal on a ranging subcarrier of the frequency domain signal obtained after the transform, the ranging signal is composed of at least two symbols in the time domain; and respectively performing phase sequences of other symbols except the first symbol Compensation, the compensation value is the equivalent phase delay of the cyclic prefix CP length;

The weighting module 602 is configured to weight combine the sequence of the first symbol and the sequence obtained by phase compensation of the other symbols to obtain a combined sequence, wherein the weighted weight is between [0, 1], and each weight The sum of the values is equal to 1 and is proportional to the amount of data carried on each symbol;

The calculating module 603 is configured to sequentially select a local code in the stored code table, perform a correlation operation using the sequence of the selected local code and the combined sequence, perform a differential operation and an FFT on the sequence obtained after the correlation operation, and calculate the The power of each value in the sequence generated by the differential operation and the transformation; the peak-to-average ratio is determined according to the power of each value in the sequence generated by the difference operation and the transformation, and the peak-to-average ratio is the sequence value generated after the differential operation and the transformation a ratio of the peak power to the average power; the first determining module 604, configured to: when the peak-to-average ratio is greater than the first threshold, determine that the received time domain signal carries the ranging code, and the first threshold is not less than Set the threshold corresponding to the upper limit of the range detection rate.

In an embodiment, the compensation module 601 may be specifically configured to: perform phase compensation on the sequences of the other symbols according to the formula = * _ex p(-_ ^^), where i, j, and k are positive integers, i > 2, N is the FFT window value, ^ represents the frequency domain value of the kth subcarrier of the ith symbol, and represents the phase compensated frequency domain value of the kth subcarrier of the ith symbol, l _cp exp (- / ^iL k)

Is the length of the CP, and N is the equivalent phase delay of the cp length. In an embodiment, the weighting module 602 can be further configured to: The coverage radius of the region determines the weighted weight, wherein the weighted weight is proportional to the coverage radius of the cell in which the single antenna is located.

In an embodiment, as shown in FIG. 7, the calculation module 603 specifically includes: a first mapping sub-module 701, configured to map the sequence obtained after the correlation operation to the corresponding ranging subcarrier;

a first difference numerator module 702, configured to sequentially formulate a sequence of η] = /.))* on a ranging subcarrier with a distance of " ^Δ /"

Carry out the difference

= ∑ H _k Hl _{n QV} (j^ n)

V is divided to obtain a sequence of length M, where l≤n≤M, n, M are positive integers, M is the maximum interval of subcarriers, Δ/ is the interval between two adjacent subcarriers, and K is all measurements From the set of subcarriers, 3⁄4 and _Hk+n are channel correlation coefficients, and _Ck and _Ck+n are sequences corresponding to the local code C.

₁₀ is the time offset of the received time domain signal, and N is the system FFT window size;

The first transform sub-module 703 is configured to complement the sequence of length M after the differential operation by N _t -M 0, and perform FFT on the sequence of length N _t formed after zero-padding, where N _{t is} not Less than M, located between [N/8, N], and the value of N _t is equal to the power of 2.

In one embodiment, the first difference numerator module 702 can be further configured to: when the subcarrier spacing is less than the coherence bandwidth, H _k = H _k+n , at this time, x[n] = k(n) _Q xp(j ^n) , where, is

N

The number of carrier pairs with a spacing of " ^Δ /" in the set of ranging subcarriers K.

In an embodiment, as shown in FIG. 8, the ranging code detecting apparatus may further include: a second determining module 801, configured to determine that a peak-to-peak ratio is greater than a second threshold, wherein an average value of the peak-to-peak power The ratio of the second threshold is not less than a threshold corresponding to a lower limit of the preset ranging code alarm rate. Based on the same inventive concept, the embodiment of the present invention further provides another ranging code detecting device. The specific structure is as shown in FIG. 9, and includes:

The obtaining module 901 is configured to perform, for each time domain signal, a sequence generated by the differential operation when performing multiple time domain signals received through multiple antennas: performing fast Fourier transform FFT on the time domain signal, and transforming Obtaining a ranging signal on the ranging subcarrier of the obtained frequency domain signal, where the ranging signal is composed of at least two symbols in the time domain; phase compensation is performed on sequences of other symbols except the first symbol, The compensation value is an equivalent phase delay of the cyclic prefix CP length; the sequence of the first symbol and the sequence obtained by phase compensation of each symbol are weighted and combined to obtain a combined sequence, wherein the weighted weight is located at [0, Between 1], the sum of the weights is equal to 1 and is proportional to the amount of data information carried on each symbol; the local code is sequentially selected in the stored code table, and the sequence of the selected local code and the merged sequence are used. Perform correlation operations and perform differential operations on sequences obtained after correlation operations;

The adding module 902 is configured to add the sequence values of the obtained sequence generated by the difference operation to obtain the added sequence, and perform FFT; calculate the power of the sequence obtained by the FFT transform, and determine a peak-to-average ratio, wherein the peak-to-average ratio is a ratio of a peak power to a mean power of each value of the sequence generated after the differential operation and the transformation;

The third determining module 903 is configured to: when the peak-to-average ratio is greater than the first threshold, determine that the received time domain signal carries the ranging code, where the first threshold is not less than the upper limit of the preset ranging code detection rate. The corresponding threshold value.

In an embodiment, the obtaining module 901 may be further configured to: perform phase compensation on the sequences of the other symbols according to the formula = * _ex p(-_ ^^), where i, j, and k are positive integers, i > 2, N is the FFT window value, ^ represents the frequency domain value of the kth subcarrier of the ith symbol, and represents the phase compensated frequency domain value of the kth subcarrier of the ith symbol, l _cp exp (- / ^iL k)

Is the length of the CP, and N is the equivalent phase delay of the cp length. In an embodiment, the obtaining module 901 may be further configured to: determine a weighted weight according to a coverage radius of a cell where the multiple antennas are located, where the weighted weight is proportional to a coverage radius of a cell where the multiple antennas are located.

In an embodiment, as shown in FIG. 10, the obtaining module 901 may include: a second mapping sub-module 1001, configured to map the sequence obtained after the correlation operation to the corresponding ranging subcarrier;

The second difference molecular module 1002 is configured to sequentially formulate the sequence η] = /.))* which is carried on the ranging subcarriers with a distance of " ^Δ /":

Carry out the difference

= ∑ H _k Hl _{n QV} (j^ n)

V is divided to obtain a sequence of length M, where l≤n≤M, n, M are positive integers, M is the maximum interval of subcarriers, Δ/ is the interval between two adjacent subcarriers, and K is all measurements From the set of subcarriers, 3⁄4 and _Hk+n are channel correlation coefficients, _Ck and _Ck+n are sequences corresponding to local code C, ₁₀ is the time offset of the received time domain signal, and N is the system FFT window. size.

In an embodiment, the second difference merging module 1002 may be further configured to: when the subcarrier spacing is less than the coherence bandwidth, H _k = H _k+n , at this time, x[n] = k(n) _Q x _V (j^n) , where,

N

Is the number of carrier pairs with a spacing of " ^Δ /" in the set of ranging subcarriers K.

In an embodiment, as shown in FIG. 11, the adding module 902 may include: an adding sub-module 1101, where values of a sequence of a sequence of length Μ obtained after the differential operation are correspondingly added to obtain a phase The sequence after the addition, the length of the added sequence is Μ;

The second transform sub-module 1102 is configured to complement N _t -M 0s after the addition, the sequence of length Μ, and perform FFT on the sequence of length N _t formed after zero-padding, where N _{t is} not Less than M, located between [N/8, N], and the value of N _t is equal to the power of 2.

In an embodiment, as shown in FIG. 12, the ranging code detecting apparatus may further include: The fourth determining module 1201 is configured to determine that a peak-to-peak ratio is greater than a second threshold, where a peak-to-peak ratio is a ratio of a mean value of the power, and the second threshold is not less than a gate corresponding to a lower limit of the preset ranging code Limit.

Further, the method for determining the ranging code by combining the first threshold value and the second threshold value overcomes the contradiction between the detection rate and the false alarm rate caused by simply relying on the peak-to-average ratio detection ranging code, and can Increase the detection rate while ensuring a low false alarm rate.

Further, the subcarriers with the interval smaller than the coherent bandwidth are calculated, and the conjugate is multiplied by the subcarriers with the interval of 1 to eliminate the fading effect of the channel, the calculation amount is greatly reduced, the computation complexity is reduced, and the computation is reduced. The use of resources can save resources, improve resource utilization, and achieve better performance with a small amount of computation.

Further, the frequency domain values of the plurality of frequency division sequences generated by the differential operation are correspondingly added to obtain the added frequency division sequence of length M, which is avoided as mentioned in other ranging code detection methods. Each sequence obtained after the differential operation is subjected to an FFT operation, which can greatly reduce the amount of calculation and save resources. The spirit and scope of the invention. Thus, it is intended that the present invention cover the modifications and modifications of the invention

Claims

Claim

A method for detecting a ranging code, the method comprising:

Phase compensation is performed on sequences of symbols other than the first symbol, and the compensation value is an equivalent phase delay of the cyclic prefix CP length;

The sequence of the first symbol and the sequence obtained by phase compensation of each of the other symbols are weighted and combined to obtain a combined sequence, wherein the weighted weight is between [0, 1], and the sum of the weights is equal to 1 . And proportional to the amount of data information carried on each symbol;

2. The method according to claim 1, wherein the sequence of the symbols other than the first symbol is separately compensated according to the formula: _λ = Υ _ί * _Q xp (-j^ k) performing phase compensation on the sequences of the other symbols, where i, j, and k are positive integers, i > 2, where N is an FFT window value, indicating the frequency domain value of the kth subcarrier of the ith symbol, ^ indicates the phase exp (- / ⁱ k) of the kth subcarrier of the ith symbol

The compensated frequency domain value, l _cp is the CP length, and N is the equivalent phase delay of the CP length.

3. The method of claim 1 wherein: the weighted weight and the single The coverage radius of the cell where the antenna is located is proportional.

The method according to any one of claims 1 to 3, wherein the differential operation and the FFT transformation on the sequence obtained after the correlation are:

Mapping the sequence obtained after the correlation operation to the corresponding ranging subcarrier;

Sequences carried on the ranging subcarriers with a distance of ^Δ / are sequentially given by the formula η] = ∑ c _k Y _k H _k exp(-7 ^ / ₀ ) * (c _k+n Y _k+n H _{k+n Q} xp(-j ¹ ") /.))*

^(k+n) "Different operation, get

丄N to a sequence of length M, where l≤n≤M, n, M are positive integers, M is the maximum interval of subcarriers, Δ/ is the interval between two adjacent subcarriers, and K represents all distances The set of carrier components, 3⁄4 and H _k+n are channel correlation coefficients, C _k and (^ ₊₁₁ are sequences corresponding to the local code C, and 1 is the time offset of the received time domain signal;

After the differential operation, the sequence of length M is complemented by N _t -M 0s, and the sequence of length N _t formed after zero padding is subjected to FFT, where N _{t is} not less than M, located at [N/8, Between N and , and the value of N _t is equal to the power of 2.

5. The method as claimed in claim 4, wherein, when the subcarrier spacing is less than the coherence _{_{bandwidth, H k = H k + n}} , x [n- \ = k (n) Q j ^ n), Where is the ranging subcarrier set K

N

The number of carrier pairs with a spacing of " ^Δ /".

The method according to any one of claims 1 to 3, characterized in that the first threshold value is between [12, 16].

The method according to any one of claims 1 to 3, wherein, after confirming that the peak-to-average ratio is greater than the first threshold, and determining that the received time domain signal carries the ranging code, the method further includes :

Determining that the peak-to-peak ratio is greater than a second threshold, wherein the peak-to-peak ratio is differential operation and conversion The second threshold is not less than a threshold corresponding to a lower limit of the preset ranging code alarm rate.

8. The method of claim 7, wherein the second threshold is located at [3,

6) between.

9. A method for detecting a ranging code, the method comprising:

When receiving multiple time domain signals via multiple antennas, each of the time domain signals is respectively subjected to the following operations to obtain a sequence generated by the differential operation: performing fast Fourier transform FFT on the time domain signal, and obtaining the frequency domain signal after the transform Obtaining a ranging signal on the ranging subcarrier; performing phase compensation on the sequences of other symbols except the first symbol, the compensation value is an equivalent phase delay of the cyclic prefix CP length; the sequence of the first symbol and other The sequence obtained by phase compensation of the symbols is weighted and combined to obtain a combined sequence, wherein the weighted weights are located between [0, 1], the sum of the weights is equal to 1, and the amount of data information carried on each symbol Directly proportional; select the local code in the stored code table, use the selected local code sequence and the combined sequence to perform correlation operations, and perform differential operations on the sequence obtained after the correlation operation;

Adding a plurality of obtained values of the sequence generated by the difference operation to obtain an added sequence, and performing FFT;

Calculating the power of the sequence obtained by the FFT transformation to determine the peak-to-average ratio;

When the peak-to-average ratio is greater than the first threshold, it is determined that the received time domain signal carries a ranging code, and the first threshold is not less than a threshold corresponding to the upper limit of the preset ranging code detection rate.

10. The method according to claim 9, wherein the sequence of the symbols other than the first symbol is separately compensated according to the formula: _λ = Υ _ί * _Q xp (-j^ k) performing phase compensation on the sequences of the other symbols, where i, j, and k are positive integers, i > 2, where N is an FFT window value, indicating the frequency domain value of the kth subcarrier of the ith symbol, ^ represents the phase of the kth subcarrier of the ith symbol The compensated frequency domain value, l _cp is the CP length,

The equivalent phase delay for the length of the CP.

The method according to claim 9, wherein the weighted weight is proportional to a coverage radius of a cell in which the multiple antennas are located.

The method according to any one of claims 9 to 11, wherein the differential operation of the sequence obtained after the correlation operation is:

Sequences carried on the ranging subcarriers with a distance of " ^Δ / according to the formula η] = ∑ c[Y _k H _k exp(-7^/ ₀ ) * (c _k+n Y _k+n H _{k+n Q} xp(-j ¹ : ") /.))*

Perform differential operation

= ∑ H _k H ₊ j^ to a sequence of length M, where l ≤ n ≤ M, n, M are positive integers, M is the maximum spacing of subcarriers, Δ / is the interval between adjacent subcarriers, K denotes a set of all ranging subcarriers, 3⁄4 and _Hk+n are channel correlation coefficients, C _k and (^ ₊₁₁ are sequences corresponding to the local code C, and 1 is the time offset of the received time domain signal.

13. The method according to claim 12, wherein when the subcarrier spacing is less than a coherence bandwidth, 3⁄4 = H _k+n , M = ^)exp(7^«) , where is a ranging Carrier set

N

The number of carrier pairs with a spacing of " ^Δ / in K.

The method according to claim 12, wherein the obtained sequence values of the plurality of sequences generated by the differential operation are correspondingly added to obtain an added sequence, and the FFT is:

The sequence values of the plurality of sequences of length Μ obtained after the differential operation are added correspondingly, and the added sequence is obtained, and the added sequence length is Μ;

After the addition, the sequence of length Μ is complemented by N _t -M 0, and the sequence of length N _t formed after zero padding is subjected to FFT, where N _{t is} not less than M, located at [N/8, Between N, and N _t The value is equal to the power of 2.

The method according to any one of claims 9 to 11, characterized in that the first threshold value is between [12, 16].

The method according to any one of claims 9 to 11, wherein, after confirming that the peak-to-average ratio is greater than the first threshold, and determining that the received time domain signal carries the ranging code, the method further includes :

The peak-to-peak ratio is determined to be greater than a second threshold value, wherein the peak-to-peak ratio is a threshold value corresponding to the differential operation and the conversion of the second threshold value that is not less than a lower limit of the preset ranging code alarm code rate.

17. The method of claim 16 wherein said second threshold is between [3, 6].

18, a ranging code detecting device, wherein the ranging code detecting device comprises: a compensation module, a weighting module, a calculating module, and a first determining module; wherein

The compensation module is configured to perform fast Fourier transform FFT on the time domain signal received by the single antenna, and obtain a ranging signal on the ranging subcarrier of the frequency domain signal obtained after the transform; and other than the first symbol The sequence of symbols is separately phase compensated, and the compensation value is an equivalent phase delay of the cyclic prefix CP length;

The weighting module is configured to weight combine the sequence of the first symbol and the sequence obtained by phase compensation of the other symbols to obtain a combined sequence, wherein the weighted weight is between [0, 1], each The sum of the weights is equal to 1 and is proportional to the amount of data information carried on each symbol; the calculation module is configured to sequentially select the local code in the stored code table, and use the sequence of the selected local code and the merged The sequence performs correlation operations; performs differential operations and FFTs on the sequence obtained after the correlation operation, and calculates the power of each value in the sequence generated after the differential operation and transformation; the power of each value in the sequence generated by the differential operation and the transformation , determine the peak-to-average ratio;

The first determining module is configured to determine when the peak-to-average ratio is greater than the first threshold The domain signal carries a ranging code, and the first threshold is not less than a threshold corresponding to an upper limit of the preset ranging code detection rate.

The device according to claim 18, wherein the compensation module separately compensates the sequences of the symbols other than the first symbol to:

}^ = ^ * _ex p(- ^ t) separately compensates the sequences of other symbols, where i, j, k are positive integers, i > 2, N is the FFT window value, and ^ represents the ith The frequency domain value of the kth subcarrier of the symbol, ^ represents the phase compensated frequency domain value of the kth subcarrier of the ith symbol, 1 exp (- / ⁱ k) ^

Is the length of the CP, and N is the equivalent phase delay of the cp length.

The device according to claim 18, wherein the weighting module is further configured to determine the weighted weight according to a coverage radius of a cell where the single antenna is located, where the weighted weight and the weight are The coverage radius of the cell in which the single antenna is located is proportional.

The device according to any one of claims 18 to 20, wherein the calculation module specifically includes: a first mapping sub-module, a first difference molecular module, and a first transform sub-module;

The first mapping submodule is configured to map the sequence obtained by the correlation operation back to the corresponding ranging subcarrier; the first difference molecular module is configured to sequentially carry the bearer on the ranging subcarrier with a distance of “ ^Δ / Order η] = ∑ c _k Y _k H _{k Qxp} (- A ₀ ) * (cl _+n Y _k+n H _k+n exp(-7 ² ") / ₀ ))* by formula ( ^ί+ " Carry out the difference

= ∑ H _k Hl _{n Q} j^n) Sub-operation, to obtain a sequence of length M, where l ≤ n ≤ M, n, M is a positive integer, M is the maximum interval of subcarriers, Δ / is adjacent The interval between subcarriers, K represents the set of all ranging subcarriers, 3⁄4 and _Hk+n are channel correlation coefficients, C _k and (^ ₊₁₁ are sequences corresponding to local code C, Lo is the time offset of the received time domain signal;

The first transform submodule is configured to complement N _t -M 0s of the sequence of length M obtained after the differential operation, and perform FFT on the sequence of length N _t formed after zero padding, where N _t Not less than M, located between [N/8, N], and the value of N _t is equal to the power of 2.

The device according to claim 21, wherein the first difference molecular module performs differential operation on a sequence carried on a ranging subcarrier separated by " ^Δ / and the subcarrier spacing is smaller than a coherent bandwidth, 3⁄4 = H _k+n , x[n-\ = k(n) _Q j^n) , where is the ranging subcarrier set K

N

The number of carrier pairs with a spacing of " ^Δ /".

The apparatus according to any one of claims 18 to 20, further comprising:

a second determining module, configured to determine that a peak-to-peak ratio is greater than a second threshold, wherein the peak-to-peak ratio is a ratio of a mean value of the power, and the second threshold is not less than a lower limit of a preset ranging code Corresponding threshold.

24, a ranging code detecting device, wherein the ranging code detecting device comprises: a obtaining module, an adding module, and a third determining module; wherein

The obtaining module, when used for multiple time domain signals received via multiple antennas, respectively performs the following operations on each time domain signal to obtain a sequence generated by the differential operation: performing fast Fourier transform FFT on the time domain signal, Obtaining a ranging signal on a ranging subcarrier of the frequency domain signal obtained after the transform; performing phase compensation on the sequences of other symbols except the first symbol, and the compensation value is an equivalent phase delay of the cyclic prefix CP length; A sequence of symbols and other sequences obtained by phase compensation are weighted and combined to obtain a combined sequence, wherein the weighted weights are between [0, 1], and the sum of the weights is equal to 1, and The amount of data carried on each symbol is proportional; the local code is sequentially selected in the stored code table, the correlation between the selected local code sequence and the combined sequence is performed, and the sequence obtained after the correlation operation is subjected to differential operation. ; The adding module is configured to add the sequence values of the obtained sequence generated by the difference operation to obtain the added sequence, and perform FFT; calculate the power of the sequence obtained by the FFT transform, Determining a peak-to-average ratio, wherein the peak-to-average ratio is a ratio of a peak power to a mean power of each value of the sequence generated after the differential operation and the transformation;

The third determining module is configured to: when the peak-to-average ratio is greater than the first threshold, determine that the received time domain signal carries a ranging code, where the first threshold is not less than a preset ranging code detection rate. The threshold corresponding to the upper limit.

The apparatus according to claim 24, wherein the obtaining module separately performs phase compensation on a sequence of symbols other than the first symbol:

}^ = ^ * _ex p(- ^ t) separately compensates the sequences of other symbols, where i, j, k are positive integers, i > 2, N is the FFT window value, and ^ represents the ith The frequency domain value of the kth subcarrier of the symbol, ^ represents the phase compensated frequency domain value of the kth subcarrier of the i-th symbol, l _cp exp (- / ⁱ k) ^

Is the length of the CP, and N is the equivalent phase delay of the cp length.

The apparatus according to claim 24, wherein the obtaining module is further configured to: determine, according to a coverage radius of a cell where the multiple antennas are located, the weighted weight, where the weighted weight is The coverage radius of the cell in which the multiple antennas are located is proportional.

The device according to any one of claims 24 to 26, wherein the obtaining module comprises: a second mapping sub-module and a second difference molecular module;

The second mapping submodule is configured to map the sequence obtained after the correlation operation to the corresponding ranging subcarrier;

The second difference molecular module is configured to sequentially carry the sequence carried on the ranging subcarriers with a distance of " ^Δ / An\= ∑ c _k Y _k H _k exp(-7 --/ ₀ ) * (c _k+n Y _k+n H _k+n exp(~7 ₀ )Υ column by formula ( ^ί+ "

= ∑ H« j^

丄N operation, to obtain a sequence of length M, where l≤n≤M, n, M are positive integers, M is the maximum interval of subcarriers, Δ/ is the interval between two subcarriers, K means all The set of ranging subcarriers, 3⁄4 and H _k+n are channel correlation coefficients, C _k and (^ ₊₁₁ are sequences corresponding to local code C, ₁₀ is the time offset of the received time domain signal, and N is the FFT window number.

The apparatus according to claim 27, wherein the second difference numerator module is further configured to: when the subcarrier spacing is less than a coherence bandwidth, H _k = H _k+n , at this time, Medium is the number of ranging of the carrier pair.

The device of claim 27, wherein the adding module comprises: an adding submodule and a second transforming submodule;

The addition sub-module, the sequence values of the sequence of the length M obtained after the differential operation are correspondingly added to obtain the added sequence, and the added sequence length is M;

The second transform submodule is configured to complement N _t -M 0s after the addition of the sequence of length M, and perform FFT on the sequence of length N _t formed after zero padding, where N _t Not less than M, located between CN/8, N], and the value of N _t is equal to the power of 2.

The device according to any one of claims 24 to 26, further comprising a fourth determining module, configured to determine that a peak-to-peak ratio is greater than a second threshold, wherein the peak-to-peak ratio power The ratio of the mean value is not less than the threshold value corresponding to the lower limit of the preset ranging code alarm rate.