CN116846722A

CN116846722A - Method and device for detecting and synchronizing frame signals based on BPLC system

Info

Publication number: CN116846722A
Application number: CN202310926960.XA
Authority: CN
Inventors: 任江涛; 邓敬贤; 温小军; 张国松
Original assignee: Core Semiconductor Technology Beijing Co ltd
Current assignee: Core Semiconductor Technology Beijing Co ltd
Priority date: 2023-07-26
Filing date: 2023-07-26
Publication date: 2023-10-03

Abstract

The embodiment of the invention discloses a method and a device for detecting and synchronizing frame signals based on a BPLC system. The embodiment of the invention determines a first CIR peak value according to at least two groups of first time domain data; determining a CIR peak-to-average ratio according to the first CIR peak value; determining that the last group of first time domain data in at least two groups of first time domain data is an OFDM symbol of SYNCP in response to the CIR peak-to-average ratio value being greater than a set threshold value, and determining a position index of the first CIR peak value in the OFDM symbol of SYNCP; adjusting the timing point to a head position of an OFDM symbol of the preamble according to the position index of the first CIR peak value; receiving at least four sets of second time domain data, and determining at least three second CIR peaks according to the at least four sets of second time domain data; and determining the last group of second time domain data as a second OFDM symbol of the SYNCM in response to the third time of the second CIR peak conforming to the V-shaped characteristic and meeting the set polarity characteristic. By the method, the probability of frame signal detection and the frame signal synchronization performance can be improved, and the calculated amount can be reduced.

Description

Method and device for detecting and synchronizing frame signals based on BPLC system

Technical Field

The invention relates to the technical field of computers, in particular to a method and a device for detecting and synchronizing frame signals based on a BPLC system.

Background

Along with development of science and technology, smart power grid meter reading systems, energy internet, smart home, industrial data acquisition and the like are more and more widely used in production and life of people, data transmission is needed in the application process, common data transmission modes comprise a broadband power line carrier communication technology (Broadband Power Line Carrier, BPLC), the conventional power line can be utilized for data transmission by adopting the broadband power line carrier communication technology, rewiring is not needed, networking is simple, cost is low, application range is wide, and information safety is guaranteed.

In the prior art, the orthogonal frequency division multiplexing (Orthogonal Frequency Division Multiplexing, OFDM) symbol in the BPLC system is a burst frame signal, the primary work of the receiver is to detect the frame signal in real time, and the effect of detecting the frame signal is to detect the arrival of the frame signal in the burst system so as to determine the busy state of the channel, and at the same time, timing synchronization can be performed so as to determine the boundary of the OFDM symbol in the frame signal; most of the existing OFDM frame signal detection and synchronization methods are carried out in the time domain, and basically comprise the following three modes, namely, the first mode is to carry out frame signal detection and synchronization by utilizing the time delay autocorrelation characteristic among time domain sampling signals; secondly, performing frame signal detection and synchronization by utilizing the cross-correlation characteristic between the time domain sampling signal and the local sampling sequence; a third mode is combined by the first mode and the second mode; the method is calculated in a recursive manner, the calculated amount is small, but the method is very sensitive to narrow-band interference, such as single-frequency sine waves, and a complex filter circuit is required to be added to influence the performance of frame synchronization; the second pair of the mode has better resistance to noise and narrowband interference, but the calculation amount, the storage and the power consumption are very large as the mutual correlation operation needs to be carried out again for each updated sampling point, and the method is difficult to realize in broadband high-speed communication application; performance and computational effort are also difficult to meet simultaneously in the manner described.

In summary, how to reduce the calculation amount while improving the probability of frame signal detection and the frame signal synchronization performance is a problem to be solved at present.

Disclosure of Invention

In view of this, the embodiments of the present invention provide a method and apparatus for detecting and synchronizing frame signals based on a BPLC system, which can improve the probability of detecting frame signals and the synchronization performance of frame signals, and reduce the amount of computation.

In a first aspect, an embodiment of the present invention provides a method for detecting and synchronizing a frame signal based on a BPLC system, where the method includes:

receiving at least two sets of first time domain data;

determining a first Channel Impulse Response (CIR) peak from the at least two sets of first time domain data;

determining a CIR peak-to-average ratio value according to the first CIR peak value;

determining that a last one of the at least two sets of first time domain data is an Orthogonal Frequency Division Multiplexing (OFDM) symbol of a SYNCP in response to the CIR peak-to-average value being greater than a set threshold, and determining a location index of the first CIR peak in the OFDM symbol of the SYNCP;

adjusting a timing point to a head position of an OFDM symbol of a preamble signal according to a position index of the first CIR peak value;

receiving at least four sets of second time domain data, wherein the second time domain data is time domain data received at a head position of an OFDM symbol of the preamble signal;

Determining at least three second CIR peaks from the at least four sets of second time domain data;

and determining that the last group of the second time domain data is a second OFDM symbol of the SYNCM in response to the third most recent time that the second CIR peak meets a V-shaped characteristic and meets a set polarity characteristic.

Optionally, the determining a first Channel Impulse Response (CIR) peak according to the at least two sets of first time domain data specifically includes:

performing Fast Fourier Transform (FFT) on the first time domain data to generate first frequency domain data;

and determining a first CIR peak value according to at least two groups of the first frequency domain data.

Optionally, the determining the first CIR peak according to at least two sets of the first frequency domain data specifically includes:

combining the at least two groups of first frequency domain data to generate first combined frequency domain data;

performing conjugate multiplication on the first combined frequency domain data and the local frequency domain data of the preamble symbol to obtain a first product;

performing Inverse Fast Fourier Transform (IFFT) on the first product to generate a set number of first CIR values;

and determining the maximum value of the set number of first CIR values as the first CIR peak value.

Optionally, the determining the CIR peak-to-average ratio according to the first CIR peak value specifically includes:

Determining a first CIR module value of the set number according to the first CIR value of the set number;

determining a first average value according to the first CIR module values of the set quantity;

and determining the ratio of the first CIR peak value to the first average value as the CIR peak-to-average ratio.

Optionally, after the timing point is adjusted to the head position of the OFDM symbol of the preamble according to the position index of the first CIR peak, the method further includes:

after the last OFDM symbol of the position index of the first CIR peak value is determined, after waiting for the position index time domain signal points, time domain data is received, and the received time domain data is the second time domain data.

Optionally, determining at least three second CIR peaks according to the at least four sets of second time domain data specifically includes:

combining the two adjacent groups of second time domain data to determine a second CIR peak value;

and updating the second time domain data to obtain the latest third second CIR peak value.

Optionally, in response to the third most recent time of the second CIR peak meeting the V-type feature and meeting the set polarity feature, determining the last set of the second time domain data as a second OFDM symbol of SYNCM specifically includes:

Responding to the latest three times that the second CIR peak value accords with the V-shaped characteristic, and acquiring a position index of the maximum value of the first CIR combined value and a first polarity;

determining a second polarity of the position index of the maximum value corresponding to the first second CIR peak value in the three latest second CIR peak values and a third polarity of the position index of the maximum value corresponding to the third second CIR peak value according to the position index of the maximum value;

in response to the first polarity being the same as the second polarity, the first polarity being opposite the third polarity, determining that the last set of the second time domain data is a second OFDM symbol of SYNCM.

In a second aspect, an embodiment of the present invention provides a device for detecting and synchronizing a frame signal based on a BPLC system, where the device includes:

a first receiving unit for receiving at least two groups of first time domain data;

a first determining unit configured to determine a first Channel Impulse Response (CIR) peak value according to the at least two sets of first time domain data;

the first determining unit is further configured to determine a CIR peak-to-average value according to the first CIR peak value;

a second determining unit, responsive to the CIR peak-to-average value being greater than a set threshold, for determining that a last one of the at least two sets of first time domain data is an Orthogonal Frequency Division Multiplexing (OFDM) symbol of SYNCP, and determining a position index of the first CIR peak in the OFDM symbol of SYNCP;

An adjusting unit, configured to adjust a timing point to a head position of an OFDM symbol of a preamble signal according to a position index of the first CIR peak;

a second receiving unit configured to receive at least four sets of second time domain data, where the second time domain data is time domain data that starts to be received at a head position of an OFDM symbol of the preamble;

a third determining unit, configured to determine at least three second CIR peaks according to the at least four sets of second time domain data;

and a fourth determining unit, responsive to the third most recent time that the second CIR peak meets a V-type characteristic and satisfies a set polarity characteristic, for determining that the last set of the second time domain data is a second OFDM symbol of SYNCM.

Optionally, the first determining unit is specifically configured to:

Optionally, the first determining unit is specifically further configured to:

Optionally, the first determining unit is specifically configured to:

Optionally, the second receiving unit is further configured to:

Optionally, the third determining unit is specifically configured to:

Optionally, the fourth determining unit is specifically configured to:

In a third aspect, an embodiment of the present invention provides an electronic device, including a memory and a processor, the memory configured to store one or more computer instructions, wherein the one or more computer instructions are executable by the processor to implement the method of the first aspect or any one of the possibilities of the first aspect.

In a fourth aspect, embodiments of the present invention provide a computer readable storage medium having stored thereon a computer program for execution by a processor to implement the method of the first aspect or any of the possibilities of the first aspect.

The embodiment of the invention receives at least two groups of first time domain data; determining a first Channel Impulse Response (CIR) peak from the at least two sets of first time domain data; determining a CIR peak-to-average ratio value according to the first CIR peak value; determining that a last one of the at least two sets of first time domain data is an Orthogonal Frequency Division Multiplexing (OFDM) symbol of a SYNCP in response to the CIR peak-to-average value being greater than a set threshold, and determining a location index of the first CIR peak in the OFDM symbol of the SYNCP; adjusting a timing point to a head position of an OFDM symbol of a preamble signal according to a position index of the first CIR peak value; receiving at least four sets of second time domain data, wherein the second time domain data is time domain data received at a head position of an OFDM symbol of the preamble signal; determining at least three second CIR peaks from the at least four sets of second time domain data; and determining that the last group of the second time domain data is a second OFDM symbol of the SYNCM in response to the third most recent time that the second CIR peak meets a V-shaped characteristic and meets a set polarity characteristic. By the method, the probability of frame signal detection and the frame signal synchronization performance can be improved, and the calculated amount can be reduced.

Drawings

The above and other objects, features and advantages of the present invention will become more apparent from the following description of embodiments of the present invention with reference to the accompanying drawings, in which:

FIG. 1 is a schematic diagram of a prior art frame format;

fig. 2 is a schematic diagram of a preamble symbol in the prior art;

FIG. 3 is a schematic diagram of a frame signal detection and synchronization structure based on a BPLC system according to an embodiment of the present invention;

FIG. 4 is a flow chart of a method for detecting and synchronizing frame signals based on a BPLC system according to an embodiment of the invention;

FIG. 5 is a flow chart of a method for determining a first CIR peak in an embodiment of the invention;

FIG. 6 is a diagram illustrating calculation of a first CIR value according to an embodiment of the present invention;

FIG. 7 is a flow chart of a method for determining CIR peak to average ratio in accordance with embodiments of the present invention;

FIG. 8 is a flow chart of a method for determining a second CIR peak in an embodiment of the invention;

FIG. 9 is a flowchart of another method for detecting and synchronizing frame signals based on a BPLC system according to an embodiment of the present invention;

FIG. 10 is a schematic diagram of a device for detecting and synchronizing frame signals based on a BPLC system according to an embodiment of the present invention;

fig. 11 is a schematic diagram of an electronic device according to an embodiment of the present invention.

Detailed Description

The present disclosure is described below based on examples, but the present disclosure is not limited to only these examples. In the following detailed description of the present disclosure, certain specific details are set forth in detail. The present disclosure may be fully understood by those skilled in the art without a review of these details. Well-known methods, procedures, flows, components and circuits have not been described in detail so as not to obscure the nature of the disclosure.

Moreover, those of ordinary skill in the art will appreciate that the drawings are provided herein for illustrative purposes and that the drawings are not necessarily drawn to scale.

Unless the context clearly requires otherwise, the words "comprise," "comprising," and the like throughout the application are to be construed as including but not being exclusive or exhaustive; that is, it is the meaning of "including but not limited to".

In the description of the present disclosure, it is to be understood that the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. Furthermore, in the description of the present disclosure, unless otherwise indicated, the meaning of "a plurality" is two or more.

In the prior art, the common data transmission mode comprises a broadband power line carrier communication technology (Broadband Power Line Carrier, BPLC), the broadband power line carrier communication technology can be used for carrying out data transmission by utilizing the existing power line, rewiring is not needed, networking is simple, cost is low, application range is wide, and information safety is guaranteed; compared with the traditional narrow-band power line communication technology, the frequency point of the BPLC is limited between 2MHz and 30MHz, the physical layer is based on the orthogonal frequency division multiplexing technology (Orthogonal Frequency Division Multiplexing, OFDM), the communication rate is generally above 1Mbps, the average communication rate is about 10Mbps, the method has obvious advantages in real-time performance and dynamic ad hoc network, is embodied in smart grid meter reading service, mainly has a meter reading rate of 100%, and can realize real-time cost control, remote real-time recharging, station area line loss analysis and the like; based on widely verified transmission control protocol/Internet protocol (Transmission Control Protocol/Internet Protocol, TCP/IP) network technology, the method has perfect link layer and network layer data protection and verification; besides data encryption of an application layer, the broadband carrier supports high-strength encryption algorithms such as data encryption labeling (Data Encryption Standard, DES), triple data encryption algorithm (Triple DES,3 DES), advanced encryption standard (Advanced Encryption Standard, AES) and the like at a link layer, so that the data communication security is high; with the advantages, the BPLC is widely applied to smart grid meter reading systems, energy Internet, smart home, industrial data acquisition and the like.

In a BPLC communication network, a transmitter and a receiver adopt the same Frame format and are composed of three parts, including a Preamble Frame Control symbol (FC) and a traffic symbol (Payload), as shown in fig. 1, the Preamble symbol (Preamble) is composed of 10.5 repeated SYNCP symbols and 2.5 SYNCMs, wherein the first 0.5 SYNCP is the result of a roll-off windowing process on the latter half of one SYNCP, the middle 10 SYNCPs are OFDM data, the time of each OFDM data is 40.96us long, the SYNCM is obtained by inverting the bits of the SYNCP symbol, the last 0.5 SYNCM is composed of data after the first half of the SYNCM is roll-off windowed, and the Preamble symbol is mainly used for Frame signal detection, timing, sampling clock bias estimation, channel estimation, and the like.

Most of the existing OFDM frame signal detection and synchronization methods are carried out in the time domain, and basically comprise the following three modes, namely, the first mode is to carry out frame signal detection and synchronization by utilizing the time delay autocorrelation characteristic among time domain sampling signals; secondly, performing frame signal detection and synchronization by utilizing the cross-correlation characteristic between the time domain sampling signal and the local sampling sequence; a third mode is combined by the first mode and the second mode; the method is calculated in a recursive manner, the calculated amount is small, but the method is very sensitive to narrow-band interference, such as single-frequency sine waves, and a complex filter circuit is required to be added to influence the performance of frame synchronization; the second pair of the mode has better resistance to noise and narrowband interference, but the calculation amount, the storage and the power consumption are very large as the mutual correlation operation needs to be carried out again for each updated sampling point, and the method is difficult to realize in broadband high-speed communication application; performance and computational effort are also difficult to meet simultaneously in the manner described. Therefore, how to reduce the amount of calculation while improving the probability of frame signal detection and the frame signal synchronization performance is a problem that needs to be solved at present.

In the embodiment of the present invention, in order to solve the above-mentioned problems, a frame signal detection and synchronization needs to be performed in a receiver, and a specific structure diagram is shown in fig. 3, where the specific structure diagram includes a SYNCP detection unit 301, a timing adjustment unit 302, and a SYNCM detection unit 303, where the SNYCP detection unit is configured to detect whether a SYNCP symbol in a preamble arrives, and when the SYNCP symbol detection is successful, the timing adjustment unit 302 is entered, and the timing adjustment unit is configured to adjust the timing of a received signal, adjust a timing point to a head position of an OFDM symbol of the preamble, and after the timing adjustment is completed, the SYNCM detection unit is entered, and the SYNCM detection unit is configured to detect whether the SYNCM symbol in the preamble arrives. As is apparent from the above description, since the preamble symbol includes two parts of the SYNCP symbol and the SYNCM symbol, the frame signal detection mainly includes a two-part process, i.e., determination of the SYNCP symbol and determination of occurrence of the SYNCM symbol, and timing adjustment is performed after determining the SYNCP symbol and before determining the SYNCM symbol, which may also be referred to as timing synchronization.

The following describes the present invention in detail by a complete embodiment, and specifically proposes a method for detecting and synchronizing frame signals based on a BPLC system, as shown in fig. 4, and fig. 4 is a schematic diagram of a method for detecting and synchronizing frame signals based on a BPLC system according to an embodiment of the present invention. The method specifically comprises the following steps:

Step S400, at least two sets of first time domain data are received.

Specifically, each set of first time domain data includes Nfft time domain signals, where the value of Nfft may be 1024 or 2048, or may be other numerical values, specifically determined according to the sampling rate.

Step S401, determining a first channel impulse response (Channel Impulse Response, CIR) peak according to the at least two sets of first time domain data.

In one possible implementation, each time a set of first time domain data is received, i.e. each time a set of Nfft time domain signals is received, performing a fast fourier transform (Fast Fourier Transform, FFT) on a set of the first time domain data to generate first frequency domain data, wherein the first frequency domain data comprises frequency domain data of Nfft points; and determining a first CIR peak value according to at least two groups of the first frequency domain data.

In this embodiment of the present invention, the determining the first CIR peak according to at least two sets of the first frequency domain data, as shown in fig. 5, includes the following steps:

and S500, combining the at least two groups of first frequency domain data to generate first combined frequency domain data.

Specifically, a plurality of sets of the first frequency domain data, that is, the first frequency domain data obtained by combining a plurality of FFT operations, where the number of the combined sets may be represented by num_cp_cmb, where the num_cp_cmb is set to be smaller than the number of symbols of SYNCP, preferably, the num_cp_cmb=8, and when the num_cp_cmb=8, the 8 sets of the first frequency domain data are combined.

In the embodiment of the present invention, it is assumed that each set of first frequency domain data includes 1024 frequency domain data, where indexes of the 1024 frequency domain data are respectively index 0, index 1, index 2, and index 3 … … index 1023, when 8 sets of the first frequency domain data are combined, that is, 8 sets of frequency domain data on index 0 are subjected to equal-ratio combination, 8 sets of frequency domain data on index 1 are subjected to equal-ratio combination, 8 sets of frequency domain data on index 2 are subjected to equal-ratio combination, 8 sets of frequency domain data on index 3 are subjected to equal-ratio combination … … sets of frequency domain data on index 1023, and the first combined frequency domain data generated after combination is denoted as cp_cmb_freq, where the first combined frequency domain data includes 1024 sets of frequency domain data.

In a possible implementation manner, if each set of first frequency domain data includes 2048 frequency domain data, the processing manner is the same as that when the set of first frequency domain data includes 1024 frequency domain data, the generated first combined frequency domain data includes 2048 frequency domain data, and other values are not described in detail, and are determined according to practical situations.

Step S501, performing conjugate multiplication on the first combined frequency domain data and the local frequency domain data of the preamble symbol to obtain a first product.

Specifically, the first combined frequency domain data is expressed as cp_cmb_freq and the local frequency domain data of the preamble symbol are subjected to conjugate multiplication, wherein the local frequency domain data of the preamble symbol is data specified in a protocol, the local frequency domain data of the preamble symbol can be expressed as prmb_loc_freq, specifically, as shown in fig. 6, the frequency domain data indexed at the same position by the cp_cmb_freq and the prmb_loc_freq are subjected to point-to-point conjugate multiplication to obtain a first product, which can be expressed as cp_cmb_mulp; for example, the cp_cmb_freq includes 1024 pieces of frequency domain data, the indexes of the 1024 pieces of frequency domain data are respectively an index (1) 0, an index (1) 1, an index (1) 2, and an index (1) 3 … … index (1) 1023, the prmb_loc_freq includes 1024 pieces of frequency domain data, the indexes of the 1024 pieces of frequency domain data are respectively an index (2) 0, an index (2) 1, an index (2) 2, and an index (2) 3 … … index (2) 1023, and the frequency domain data at the position of the index (1) 0 is conjugate multiplied with the frequency domain data at the position of the index (2) 0, so as to generate the frequency domain data at the position of the index (3) 0 of the first product cp_cmb_mulp; the frequency domain data of the index (1) 1 position is multiplied by the frequency domain data of the index (2) 1 position in a conjugate way to generate frequency domain data of the index (3) 1 position of a first product CP_CMB_MULP; similarly, the frequency domain data at the position 1023 of the index (1) is multiplied by the frequency domain data at the position 1023 of the index (2) in a conjugate manner to generate the frequency domain data at the position 1023 of the index (3) of the first product cp_cmb_mulp.

In one possible implementation manner, when the Band number of the frame signal (i.e., the first time domain data) is known, the prmb_loc_freq takes the frequency domain data of the subcarrier corresponding to the Band number, and the other subcarriers are all set to 0; for example, BAND0 occupies 411 points, and all points except the 411 points are set to 0 among 1024 points; when the Band number of the unknown frame signal is selected, selecting all subcarrier frequency domain data corresponding to each Band number, and setting other subcarriers to 0; for example, BAND0 occupies 411 points, and all points except the 411 points are set to 0 among 1024 points; the BAND0 occupies 411 points, and the index is from 80 to 490; the band1 occupies 131 points, the index is from 100 to 230, the repetition is occupied, and other points except the occupied point in 1024 points are all set to 0.

Step S502, performing inverse fast fourier transform (Inverse Fast Fourier Transform, IFFT) on the first product to generate a set number of first CIR values.

Specifically, performing IFFT operation on the first product cp_cmb_mulp, as shown in fig. 6, to obtain a first CIR value, denoted as cp_cmb_cir, and assuming that the first product includes 1024 points, generating 1024 first CIR values according to the first product; if the first product includes 2048 points, 2048 first CIR values are generated according to the first product, and the first CIR values are determined according to actual conditions, which is not limited in the embodiment of the present invention.

Step S503, determining a maximum value of the set number of first CIR values as the first CIR peak value.

Specifically, 1024 first CIR values are generated according to the first product, or 2048 first CIR values are generated according to the first product, and specific values are determined according to actual situations, which is not limited in the embodiment of the present invention.

And step S402, determining a CIR peak-to-average ratio value according to the first CIR peak value.

Specifically, as shown in fig. 7, the flowchart for determining the CIR peak-to-average value according to the first CIR peak value includes the following steps:

step S700, determining the first CIR module values of the set number according to the first CIR values of the set number.

Specifically, assuming that the number of first CIR values is 1024, that is, the number of cp_cmb_cirs is 1024, 1024 first CIR modulus values are determined, which are denoted as cp_cmb_cir_abs; obtaining a maximum value CP_CIR_MAXV in a modulus value sequence of the 1024 first CIR modulus values and a position index CP_CIR_MAXV_IDX of the maximum value; it is assumed that the modulus value at the index 3 position in the modulus value sequence of 1024 first CIR modulus values is the maximum value in the modulus value sequence, which is only illustrated here as an example, and is specifically determined according to the actual situation.

Step S701, determining a first average value according to the set number of first CIR modules.

Specifically, a sum of the first CIR modulus values of the set number is determined, and a ratio of the sum to the set number is determined as the first average value and is recorded as cp_cmb_cir_avg.

For example, a sum of 1024 first CIR modulus values cp_cmb_cir_abs is determined, and a ratio of the sum to 1024 is determined as the first average.

In one possible implementation, after one peak value is removed from the 1024 first CIR modules, calculating a sum value of the remaining 1023 first CIR modules, and determining a ratio of the sum value to the 1023 as the first average value; or, removing the largest ones of the 1024 first CIR modules, for example, removing the largest ones of the 4 sequences, calculating the sum of the remaining 1020 first CIR modules, and determining the ratio of the sum to 1020 as the first average.

Step S702, determining the ratio of the first CIR peak value to the first average value as the CIR peak-to-average value ratio.

Specifically, the CIR peak-to-average ratio is expressed as CP_CIR_MAXV/CP_CMB_CIR_AVG.

Step S403, in response to the CIR peak-to-average value being greater than a set threshold, determining that a last one of the at least two sets of first time domain data is an Orthogonal Frequency Division Multiplexing (OFDM) symbol of SYNCP, and determining a position index of the first CIR peak in the OFDM symbol of SYNCP.

Specifically, assuming that the set threshold is denoted as cp_cir_p2a_thr, when the CIR peak-to-average value is greater than the cp_cir_p2a_thr, determining that the SYNCP detection is successful, that is, determining that the received first time domain data is an OFDM symbol of SYNCP.

In one possible implementation manner, while determining that the CIR peak-to-average value is greater than the cp_cir_p2a_thr, determining whether the cp_cir_maxv is greater than the set threshold cp_cir_maxv_thr of the maximum cp_cir_maxv, and if the cp_cir_maxv is greater than the set threshold cp_cir_maxv_thr of the maximum cp_cir_maxv, determining that the SYNCP detection is successful, that is, determining that the received first time domain data is an OFDM symbol of SYNCP.

In one possible implementation, if the SYNCP detection fails, time domain data is continuously received, and the above procedure is repeated for SYNCP detection.

In the embodiment of the present invention, in the SYNCP detection process, the first time domain data is generated by performing real-time automatic gain control (Automatic Gain Control, AGC) estimation and adjustment on a time domain signal.

Step S404, adjusting the timing point to the head position of the OFDM symbol of the preamble signal according to the position index of the first CIR peak value.

Specifically, after the SYNCP detection is successful, starting timing adjustment, and adjusting the timing point of receiving the time domain data to the head position of the next OFDM symbol according to the position index cp_cir_maxv_idx of the first CIR peak; and adjusting the timing point to a head position of an OFDM symbol of the preamble according to the position index of the first CIR peak, the method further comprising: and after the last OFDM symbol of the position index of the first CIR peak value is determined, waiting for the position index CP_CIR_MAXV_IDX time domain signal points, and then receiving time domain data, wherein the received time domain data is the second time domain data.

In one possible implementation, the AGC estimation and adjustment of the time domain signal is stopped after the timing point is adjusted to the head position of the OFDM symbol of the preamble.

Step S405, receiving at least four sets of second time domain data, where the second time domain data is time domain data received at a head position of an OFDM symbol of the preamble signal.

Specifically, each set of second time domain data includes Nfft time domain signals, where the value of Nfft may be 1024 or 2048, or may be other numerical values, specifically determined according to the sampling rate.

In the embodiment of the invention, at least three CIR peaks are needed when the SYNCM is tested, and two sets of time domain data are needed when each CIR peak is calculated, so that at least four sets of second time domain data are needed to be received to realize the test of the SYNCM.

In one possible implementation, the second time-domain data that starts to be received after timing adjustment may be the 6 th or 7 th symbol in SYNCP, which is specifically determined according to the actual situation, and is only illustrated here, so that it may be necessary to receive more than four sets of the second time-domain data to implement the check of SYNCM.

Step S406, determining at least three second CIR peaks according to the at least four sets of second time domain data.

Specifically, the second CIR peak value is determined after the two adjacent groups of second time domain data are combined; and updating the second time domain data to obtain the latest third second CIR peak value.

In the embodiment of the present invention, after the merging according to the two adjacent sets of the second time domain data, one second CIR peak value is determined, as shown in fig. 8, and the method includes the following steps:

step S800, merging the two sets of second frequency domain data to generate second merged frequency domain data.

Specifically, the two sets of the second frequency domain data are combined, that is, the second frequency domain data obtained by the two FFT operations are combined.

Assuming that each set of second frequency domain data includes 1024 frequency domain data, indexes of the 1024 frequency domain data are respectively index 0, index 1, index 2 and index 3 … … index 1023, when 2 sets of the second frequency domain data are combined, namely 2 sets of frequency domain data on index 0 are subjected to equal-ratio combination, 2 sets of frequency domain data on index 1 are subjected to equal-ratio combination, 2 sets of frequency domain data on index 2 are subjected to equal-ratio combination, 2 sets of frequency domain data on index 3 are subjected to equal-ratio combination, … … sets of frequency domain data on index 1023 are subjected to equal-ratio combination, and second combined frequency domain data generated after combination are expressed as CM_CMB_FREQ, wherein 1024 sets of frequency domain data are included in the second combined frequency domain data.

In a possible implementation manner, if each set of second frequency domain data includes 2048 frequency domain data, the processing manner is the same as that when the second set of second frequency domain data includes 1024 frequency domain data, and the generated second combined frequency domain data includes 2048 frequency domain data, which are not described in detail, and are specifically determined according to the actual situation.

Step S801, performing conjugate multiplication on the second combined frequency domain data and the local frequency domain data of the preamble symbol to obtain a second product.

Specifically, the second combined frequency domain data is expressed as cm_cmb_freq and the local frequency domain data of the preamble symbol are subjected to conjugate multiplication, wherein the local frequency domain data of the preamble symbol is data specified in a protocol, the local frequency domain data of the preamble symbol can be marked as prmb_loc_freq, and the frequency domain data indexed by the cm_cmb_freq and the prmb_loc_freq at the same position are subjected to point-to-point conjugate multiplication to obtain a second product, which can be expressed as cm_cmb_mulp; for example, the cm_cmb_freq includes 1024 pieces of frequency domain data, the indexes of the 1024 pieces of frequency domain data are respectively an index (4) 0, an index (4) 1, an index (4) 2, and an index (4) 3 … … index (4) 1023, the prmb_loc_freq includes 1024 pieces of frequency domain data, the indexes of the 1024 pieces of frequency domain data are respectively an index (5) 0, an index (5) 1, an index (5) 2, and an index (5) 3 … … index (5) 1023, and the frequency domain data at the position of the index (4) 0 is conjugate multiplied with the frequency domain data at the position of the index (5) 0, so as to generate frequency domain data at the position of an index (6) 0 of the second product cm_cmb_mulp; the frequency domain data of the index (4) 1 position is multiplied by the frequency domain data of the index (5) 1 position in a conjugate way to generate frequency domain data of the index (6) 1 position of a second product CM_CMB_MULP; similarly, the frequency domain data at the position of the index (4) 1023 is multiplied by the frequency domain data at the position of the index (5) 1023 in a conjugate manner to generate frequency domain data at the position of the index (6) 1023 of the second product cm_cmb_mulp.

Step S802, performing inverse fast fourier transform (Inverse Fast Fourier Transform, IFFT) on the second product to generate a set number of second CIR values.

Specifically, performing an IFFT operation on the second product cm_cmb_mulp to obtain a second CIR value, denoted as cm_cmb_cir, and assuming that the second product includes 1024 points, generating 1024 second CIR values according to the second product; if the second product includes 2048 points, 2048 second CIR values are generated according to the second product, and the second CIR values are determined according to actual conditions, which is not limited in the embodiment of the present invention.

Step S803, determining a maximum value of the set number of second CIR values as the second CIR peak value.

Specifically, 1024 second CIR values are generated according to the second product, or 2048 second CIR values are generated according to the second product, and specific values are determined according to actual situations, which is not limited in the embodiment of the present invention.

In the embodiment of the invention, the modulus value CM_CMB_CIR_ABS of the CM_CMB_CIR is calculated, the maximum value thereof is found out in 1024 modulus value sequences and is used as the second CIR peak value, which is marked as CM_CIR_MAXV, and the symbol polarity of each M CIR values of the CM_CMB_CIR around the index 0 is recorded and is marked as CM_CIR_SIGN [2M+1].

In one possible implementation, if m=3, the second CIR peak cm_cir_maxv is a peak in M values around cm_cmb_cir_abs index 0 and index 0, i.e. the second CIR peak is a peak in 3 values around cm_cmb_cir_abs index 0 and index 0.

In this embodiment of the present invention, the second time domain data is updated, one second CIR peak value is obtained every two sets, the second CIR peak values are obtained three times in total, the peak values of the three times of the last CIR are respectively denoted as cm_cir_maxv1, cm_cir_maxv2 and cm_cir_maxv3, the polarity array corresponding to the cm_cir_maxv1 is cm_cir_sign1[2m+1], the polarity array corresponding to the cm_cir_maxv2 is cm_cir_sign2[2m+1], and the polarity array corresponding to the cm_cir_maxv3 is cm_cir_sign3[2m+1].

In one possible implementation, when the real part of the second CIR value is positive, its corresponding polarity decision is +1, otherwise, its corresponding polarity decision is-1.

Step S407, in response to the latest three times that the second CIR peak meets the V-type feature and meets the set polarity feature, determining that the last set of the second time domain data is the second OFDM symbol of SYNCM.

Specifically, expanding the step S407, as shown in fig. 9, a specific flowchart includes the following steps:

and step 900, responding to the latest three times that the second CIR peak value accords with the V-shaped characteristic, and acquiring the position index of the maximum value of the first CIR combined value and the first polarity.

Specifically, after the third second CIR peak value is obtained, V-type judgment is started, whether the third second CIR peak value accords with the V-type feature is judged, if the third second CIR peak value accords with the V-type feature, processing is continued, if the third second CIR peak value does not accord with the V-type feature, new time domain data is continuously received, FFT operation is performed, a new second CIR peak value is generated, and the third second CIR peak value is the latest third second CIR peak value when V-type judgment is performed each time.

For example, the second CIR peaks of the last three times are cm_cir_maxv1, cm_cir_maxv2, and cm_cir_maxv3, and it is determined whether the cm_cir_maxv1, the cm_cir_maxv2, and the cm_cir_maxv3 satisfy a V-type feature, and if cm_cir_maxv1> cm_cir_maxv2, and cm_cir_maxv3> cm_cir_maxv2, it is determined that the cm_cir_maxv1, the cm_cir_maxv2, and the cm_cir_maxv3 satisfy a V-type feature.

In one possible implementation manner, the obtaining the position index of the maximum value of the first CIR combination value and the first polarity is specifically as follows: when the CYNCP detection is successful, the first CIR value (cp_cmb_cir) is obtained and stored in a set position, the first CIR combination value is calculated smoothly according to the cp_cmb_cir and the second CIR value (cm_cmb_cir), the first CIR combination value generated after the smoothing calculation is stored in the set position where the cp_cmb_cir is stored, that is, the cp_cmb_cir in the set position is updated, and so on, wherein the first CIR combination value=cp_cmb_cir+cm_cmb_cir (1-Factor), the Factor is a value smaller than 1 and larger than 0, preferably, the factor=3/4 is set, and the Factor can be set to other values, which is not limited by the present invention.

In the embodiment of the invention, a module value cp_cmb_cir_abs of the first CIR combination value is calculated, a maximum value index corresponding to a maximum value in a plurality of values in a range of M values of the module value at the position of an index 0 and around the index 0 is determined, the maximum value index is marked as maxv_idx, and a polarity maxv_sign corresponding to the maximum value index is determined.

In one possible implementation, the maximum value index of the first CIR combination value of the latest 3 times is obtained, and the maximum value index is respectively denoted as maxv_idx1, maxv_idx2, and maxv_idx3, and the polarity is respectively denoted as maxv_sig1, maxv_sig2, and maxv_sig3.

Step S901, determining a second polarity of the position index of the maximum value corresponding to the first CIR peak value of the third latest three times of second CIR peaks and a third polarity of the position index of the maximum value corresponding to the third second CIR peak value according to the position index of the maximum value.

Specifically, when the cm_cir_maxv1, the cm_cir_maxv2, and the cm_cir_maxv3 satisfy the V-type feature, the polarity values of the maximum value index maxv_idx1 of the first CIR combination value in the polarity arrays cm_cir_sign1[2m+1] and cm_cir_sign3[2m+1] are respectively obtained, and are respectively denoted as cm_sign 1=cm_cir_sign 1[ maxv_idx1] and cm_sign 3=cm_cir_sign 3[ maxv_idx3].

For example, assuming that the maximum value index maxv_idx1 of the first CIR combination value is index 2, the polarity values of the index 2 in the polarity arrays cm_cir_sign1[2m+1] and cm_ci_sign3[2m+1] are obtained.

Step S902, in response to the first polarity being the same as the second polarity, the first polarity being opposite to the third polarity, determines that the last set of the second time domain data is a second OFDM symbol of SYNCM.

Specifically, if the maxv_signal1=cm_signal1 satisfies the polarity-co-directional characteristic and the maxv_signal1= -cm_signal3 satisfies the polarity-reverse characteristic, then the SYNCM detection is judged to be successful. At this time, determining that the last set of the second time domain data is a second OFDM symbol of SYNCM; the penultimate set of the second time domain data is the first OFDM symbol of SYNCM.

In one possible implementation manner, if the maxv_sig1=cm_sig1 does not satisfy the polarity co-directional feature and/or the maxv_sig1= -cm_sig3 does not satisfy the polarity reversing feature, then the SYNCM detection is determined to fail, the time domain data is continuously received, the FFT operation is performed, and the above processing manner is repeated.

According to the embodiment of the invention, the probability of frame signal detection and the frame signal synchronization performance are improved by the method.

Fig. 10 is a schematic diagram of a device for detecting and synchronizing frame signals based on a BPLC system according to an embodiment of the present invention. As shown in fig. 10, the apparatus of the present embodiment includes a first receiving unit 1001, a first determining unit 1002, a second determining unit 1003, an adjusting unit 1004, a second receiving unit 1005, a third determining unit 1006, and a fourth determining unit 1007.

Wherein the first receiving unit 1001 is configured to receive at least two sets of first time domain data; the first determining unit 1002 is configured to determine a first Channel Impulse Response (CIR) peak according to the at least two sets of first time domain data; the first determining unit 1002 is further configured to determine a CIR peak-to-average value according to the first CIR peak value; the second determining unit 1003 is configured to determine that a last one of the at least two sets of first time domain data is an Orthogonal Frequency Division Multiplexing (OFDM) symbol of SYNCP in response to the CIR peak-to-average value being greater than a set threshold, and determine a position index of the first CIR peak in the OFDM symbol of SYNCP; the adjusting unit 1004 is configured to adjust a timing point to a head position of an OFDM symbol of the preamble signal according to a position index of the first CIR peak; the second receiving unit 1005 is configured to receive at least four sets of second time domain data, where the second time domain data is time domain data received at a head position of an OFDM symbol of the preamble; the third determining unit 1006 is configured to determine at least three second CIR peaks according to the at least four sets of second time domain data; the fourth determining unit 1007 is configured to determine that the last set of the second time domain data is the second OFDM symbol of SYNCM in response to the third most recent time that the second CIR peak meets the V-shape feature and meets the set polarity feature.

Further, the first determining unit is specifically configured to:

Further, the first determining unit is specifically further configured to:

Further, the first determining unit is specifically configured to:

Further, the second receiving unit is further configured to:

and after the position indexes the time domain signal points, receiving time domain data, wherein the received time domain data is the second time domain data.

Further, the third determining unit is specifically configured to:

Further, the fourth determining unit is specifically configured to:

Fig. 11 is a schematic diagram of an electronic device according to an embodiment of the present invention. The electronic device shown in fig. 11 is an apparatus for detecting and synchronizing a frame signal, and includes a general-purpose computer hardware structure including at least a processor 1101 and a memory 1102. The processor 1101 and the memory 1102 are connected through a bus 1103. The memory 1102 is adapted to store instructions or programs executable by the processor 1101. The processor 1101 may be a stand-alone microprocessor or may be a set of one or more microprocessors. Thus, the processor 1101 performs the processing of data and control of other devices by executing instructions stored by the memory 1102, thereby performing the method flow of embodiments of the present invention as described above. The bus 1103 connects the above-described components together, while connecting the above-described components to a display controller 1104 and a display device and an input/output (I/O) device 1105. Input/output (I/O) devices 1105 may be mice, keyboards, modems, network interfaces, touch input devices, somatosensory input devices, printers, and other devices which are well known in the art. Typically, the input/output devices 1105 are connected to the system through input/output (I/O) controllers 1106.

As will be appreciated by one skilled in the art, aspects of embodiments of the present invention may be embodied as a system, method or computer program product. Accordingly, aspects of embodiments of the invention may take the form of: an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects that may all generally be referred to herein as a "circuit," module "or" system. Furthermore, aspects of embodiments of the invention may take the form of: a computer program product embodied in one or more computer-readable media having computer-readable program code embodied thereon.

Any combination of one or more computer readable media may be utilized. The computer readable medium may be a computer readable signal medium or a computer readable storage medium. The computer readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of the computer-readable storage medium would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of embodiments of the present invention, a computer-readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device.

The computer readable signal medium may include a propagated data signal with computer readable program code embodied therein, such as in baseband or as part of a carrier wave. Such a propagated signal may take any of a variety of forms, including, but not limited to: electromagnetic, optical, or any suitable combination thereof. The computer readable signal medium may be any of the following: a computer-readable storage medium is not a computer-readable storage medium and can communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device.

Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing.

Computer program code for carrying out operations for aspects of embodiments of the present invention may be written in any combination of one or more programming languages, including: object oriented programming languages such as Java, smalltalk, C ++, etc.; and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package; executing partly on the user computer and partly on the remote computer; or entirely on a remote computer or server. In the latter scenario, the remote computer may be connected to the user's computer through any type of network, including a Local Area Network (LAN) or a Wide Area Network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet service provider).

The flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the invention described above describe aspects of embodiments of the invention. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable medium that can direct a computer, other programmable data processing apparatus, or other devices to function in a particular manner, such that the instructions stored in the computer-readable medium produce an article of manufacture including instructions which implement the function/act specified in the flowchart and/or block diagram block or blocks.

The computer program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatus or other devices to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide processes for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.

The above description is only of the preferred embodiments of the present invention and is not intended to limit the present invention, and various modifications and variations may be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for detecting and synchronizing frame signals based on a BPLC system, the method comprising:

receiving at least two sets of first time domain data;

2. The method of claim 1, wherein the determining a first Channel Impulse Response (CIR) peak from the at least two sets of first time domain data, comprises:

3. The method of claim 2, wherein determining the first CIR peak from at least two sets of the first frequency domain data, specifically comprises:

4. The method of claim 3, wherein said determining a CIR peak-to-average value from said first CIR peak value comprises:

5. The method of claim 1, wherein after the timing point is adjusted to the head position of the OFDM symbol of the preamble based on the position index of the first CIR peak, the method further comprises:

6. The method of claim 1, wherein determining at least three second CIR peaks from the at least four sets of second time domain data, comprises:

7. The method of claim 1, wherein determining that the last set of the second time domain data is a second OFDM symbol of SYNCM in response to the last three times the second CIR peak meets a V-shape characteristic and meets a set polarity characteristic, comprises:

8. A device for detecting and synchronizing frame signals based on a BPLC system, the device comprising:

9. An electronic device comprising a memory and a processor, wherein the memory is configured to store one or more computer instructions, wherein the one or more computer instructions are executed by the processor to implement the method of any of claims 1-7.

10. A computer readable storage medium having stored thereon a computer program, characterized in that the program is executed by a processor to implement the method of any of claims 1-7.