Dual-mode carrier communication system hrf signal synchronization method, device and system

Abstract

The application discloses a kind of dual-mode carrier communication system HRF signal synchronization method, device and system, belong to power carrier communication technical field.The method includes: based on the maximum residual frequency deviation range allowed, frequency deviation range is divided into several frequency deviation hypothesis intervals;According to each frequency deviation hypothesis interval, respectively to receiving signal is frequency deviation pre-compensation, obtain multiple frequency deviation compensation signals, and respectively with local reference sequence is cross-correlation processing, obtain multiple cross-correlation value sequences;In any cross-correlation value sequence, the cross-correlation value of adjacent symbol interval is autocorrelation processing, obtain corresponding autocorrelation sequence;Corresponding correlation peak value is extracted from multiple autocorrelation sequences respectively with each frequency deviation hypothesis, and maximum correlation peak value is determined therefrom, if maximum correlation peak value is greater than synchronization determination threshold then determine corresponding position as synchronization position.The application realizes high-precision wireless signal synchronization, guarantees high-quality signal transmission.

Description

Technical Field

[0001] This invention belongs to the field of power line carrier communication technology, and particularly relates to a method, apparatus and electronic equipment for HRF signal synchronization in a dual-mode carrier communication system. Background Technology

[0002] With the integration and development of power line communication (PLC) and wireless communication technologies, dual-mode carrier communication systems are gradually being widely used in fields such as smart grids, smart homes, and the Internet of Things.

[0003] High-speed radio frequency (HRF) is a high-data-rate communication protocol used in dual-mode carrier communication systems. It supports multiple frequency band configurations (e.g., first, second, and third bands) and employs structures such as preamble symbols and short training fields (STFs) for signal synchronization and channel estimation. In complex power line channels and multipath fading environments, accurate and reliable wireless signal frame synchronization is one of the key technologies for ensuring system communication performance.

[0004] In related technologies, autocorrelation methods are commonly used to synchronize wireless signals using the HRF communication protocol. However, when the subcarrier spacing of the wireless signal is narrow, the frequency offset estimation range of the autocorrelation method can only cover a portion of the subcarrier spacing, making it difficult to accurately estimate the frequency offset of the wireless signal, resulting in poor signal synchronization performance. Summary of the Invention

[0005] This invention aims to at least solve one of the technical problems existing in related technologies. To this end, this invention proposes a method, apparatus, and system for HRF signal synchronization in a dual-mode carrier communication system to achieve high-precision wireless signal synchronization.

[0006] In a first aspect, the present invention provides a method for HRF signal synchronization in a dual-mode carrier communication system, the method comprising:

[0007] Based on the maximum allowable residual frequency offset range, the frequency offset range is divided into several frequency offset hypothesis intervals, and each frequency offset hypothesis interval corresponds to a frequency offset hypothesis.

[0008] The received signal is pre-compensated for frequency offset according to each frequency offset assumption interval to obtain multiple frequency offset compensation signals.

[0009] The multi-channel frequency offset compensation signals are cross-correlated with the local reference sequence to obtain a multi-channel cross-correlation value sequence.

[0010] In any cross-correlation value sequence, autocorrelation processing is performed on the cross-correlation values ​​between adjacent symbols to obtain the corresponding autocorrelation sequence;

[0011] The correlation peaks corresponding to each frequency offset hypothesis are extracted from the multi-path autocorrelation sequences, and the maximum correlation peak is determined from them.

[0012] If the maximum correlation peak value is greater than the synchronization determination threshold, the position corresponding to the maximum correlation peak value is determined as the synchronization position.

[0013] Secondly, the present invention provides an HRF signal synchronization device for a dual-mode carrier communication system, the device comprising:

[0014] The partitioning module is used to divide the frequency offset range into several frequency offset hypothesis intervals based on the maximum allowable residual frequency offset range, with each frequency offset hypothesis interval corresponding to a frequency offset hypothesis.

[0015] The pre-compensation module is used to perform frequency offset pre-compensation on the received signal according to each frequency offset assumption interval to obtain multiple frequency offset compensation signals;

[0016] The cross-correlation module is used to perform cross-correlation processing on the multi-channel frequency offset compensation signals with the local reference sequence to obtain a multi-channel cross-correlation value sequence.

[0017] The autocorrelation module is used to perform autocorrelation processing on the cross-correlation values ​​of adjacent symbol intervals in any cross-correlation value sequence to obtain the corresponding autocorrelation sequence;

[0018] The determination module is used to extract the correlation peaks corresponding to each frequency offset hypothesis from the multi-path autocorrelation sequences, and to determine the maximum correlation peak.

[0019] The determining module is further configured to determine the position corresponding to the maximum correlation peak as the synchronization position when the maximum correlation peak is greater than the synchronization determination threshold.

[0020] Thirdly, the present invention provides an electronic device including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the HRF signal synchronization method of the dual-mode carrier communication system as described in the first aspect above.

[0021] Fourthly, the present invention provides a dual-mode carrier communication system, including a transmitting end and a receiving end, wherein the receiving end and the transmitting end are communicatively connected, and the dual-mode carrier communication system, when executed by a processor, implements the HRF signal synchronization method of the dual-mode carrier communication system as described in the first aspect above.

[0022] Fifthly, the present invention provides a non-transitory computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the HRF signal synchronization method for a dual-mode carrier communication system as described in the first aspect above.

[0023] In a sixth aspect, the present invention provides a chip comprising a processor and a communication interface, the communication interface being coupled to the processor, the processor being used to run computer programs or instructions to implement the HRF signal synchronization method of the dual-mode carrier communication system as described in the first aspect above.

[0024] In a seventh aspect, the present invention provides a computer program product, including a computer program that, when executed by a processor, implements the HRF signal synchronization method for a dual-mode carrier communication system as described in the first aspect above.

[0025] The wireless signal synchronization method, apparatus, electronic device, system, non-transitory computer-readable storage medium, chip, and computer program product of the dual-mode carrier communication system provided by the present invention divides the maximum allowed residual frequency offset in the communication protocol into several frequency offset assumption intervals, providing a compensation benchmark for different frequency offset scenarios, avoiding the failure of single compensation due to excessive frequency offset range, and reducing invalid compensation; by performing frequency offset pre-compensation on the received signal according to each frequency offset assumption interval, multiple frequency offset compensation signals are obtained, covering the entire residual frequency offset range allowed by the communication protocol. For any unknown frequency offset, the influence of frequency offset can be effectively reduced, providing high-quality input for subsequent correlation processing; for the pre-frequency offset compensation signal, by first performing cross-correlation processing on the multiple frequency offset compensation signals, and then performing autocorrelation operation on the cross-correlation result, the organic combination of cross-correlation and autocorrelation is achieved, enabling the signal energy to be further superimposed on the multiple cross-correlation value sequences when there are few sampling points in the short training sequence, thereby significantly improving the amplitude of the correlation peak. Compared to a single autocorrelation or cross-correlation method, this invention can generate more obvious peak characteristics, improve the accuracy of determining the synchronization position in low signal-to-noise ratio environments, accurately find the synchronization position in low signal-to-noise ratio and frequency offset interference environments, improve the robustness and reliability of synchronization detection, and ensure the stable operation of the dual-mode carrier communication system under complex channel conditions.

[0026] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0027] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0028] Figure 1This is a flowchart illustrating the HRF signal synchronization method for a dual-mode carrier communication system provided in some embodiments of the present invention;

[0029] Figure 2 This is a schematic diagram of the autocorrelation processing performed on the multi-channel frequency offset compensation signals after cross-correlation processing provided in some embodiments of the present invention;

[0030] Figure 3 This is a schematic diagram of multi-channel frequency offset compensation signal processing provided in some embodiments of the present invention;

[0031] Figure 4 This is a schematic diagram of the HRF signal synchronization method for a dual-mode carrier communication system provided in some embodiments of the present invention;

[0032] Figure 5 This is a schematic diagram of the structure of the HRF signal synchronization device for a dual-mode carrier communication system provided in some embodiments of the present invention;

[0033] Figure 6 This is a schematic diagram of the structure of an electronic device provided in some embodiments of the present invention. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0035] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the terminology used in the specification of this application is for the purpose of describing particular embodiments only and is not intended to limit the invention; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings are used to distinguish different objects, not to describe a particular order or hierarchy.

[0036] In this invention, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this invention can be combined with other embodiments.

[0037] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0038] In this invention, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this invention, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0039] In this invention, "multiple" refers to two or more (including two), similarly, "multiple groups" refers to two or more (including two groups), and "multiple pieces" refers to two or more (including two pieces).

[0040] The HRF protocol requires high frame synchronization accuracy for wireless signals. In application scenarios with low signal-to-noise ratios, large synchronization deviations can easily lead to wireless signal synchronization failure, resulting in the inability to transmit data normally, causing communication system disconnection and data loss. Furthermore, due to limitations in crystal oscillator accuracy, environmental temperature variations, electromagnetic interference, and other complex factors, the received signal is highly susceptible to frequency shifts, leading to missed communication frames or synchronization failures, severely restricting further improvements in system performance.

[0041] Current synchronization methods based on the HRF protocol mostly employ delay autocorrelation calculation based on STF (Short Transmission Frequency). Specifically, at the receiver, the STF symbol sequence is extracted from the received radio signal frame. Utilizing the periodic structure of short symbols, delay autocorrelation calculation is used to detect synchronization peaks, thereby determining the start position of the radio signal frame. However, in narrow bandwidth scenarios, the STF method suffers from limitations in frequency offset estimation. In narrow bandwidth scenarios, the STF duration is short, and the spacing between adjacent subcarriers is small. The autocorrelation-based scheme can only estimate the frequency offset of an incomplete subcarrier spacing, easily leading to missed autocorrelation peaks and making radio signal synchronization difficult.

[0042] Therefore, there is an urgent need for a wireless signal synchronization mechanism that can maintain a high signal synchronization success rate in complex frequency offset scenarios and cover the residual frequency offset range in the communication protocol.

[0043] In view of this, this invention proposes a HRF signal synchronization method for a dual-mode carrier communication system. This method pre-compensates based on the residual frequency offset value in the communication protocol to obtain multiple compensated signals covering different frequency offset assumptions. Subsequently, cross-correlation calculations are performed on the pre-compensated wireless signals, and further autocorrelation processing is applied based on the cross-correlation results. This effectively reduces the impact of frequency offset on the correlation results while ensuring the prominence of the synchronization peak. This approach not only covers the maximum residual frequency offset range in the communication protocol, reducing the frequency offset correction burden in subsequent demodulation processes, but also reduces the demodulation bit error rate, significantly improving the overall performance and stability of the communication system in complex frequency offset environments.

[0044] The HRF signal synchronization method for a dual-mode carrier communication system provided by the present invention will be described in detail below with reference to the accompanying drawings, through specific embodiments and application scenarios.

[0045] The HRF signal synchronization method for a dual-mode carrier communication system provided in this embodiment of the invention can be executed by an electronic device or a functional module or entity in an electronic device that can implement the HRF signal synchronization method for the dual-mode carrier communication system.

[0046] The electronic device can be, for example, a terminal device, such as a power line communication terminal, a concentrator device, a smart meter, a communication module embedded device, or a communication test terminal. Alternatively, the electronic device can also be a device with computing capabilities or an intelligent robot, used to perform signal reception, processing, and subsequent possible processing tasks in this invention.

[0047] The following description uses the receiving electronic device as an example to illustrate the HRF signal synchronization method of the dual-mode carrier communication system provided in this embodiment of the invention.

[0048] Figure 1 This is a flowchart illustrating the HRF signal synchronization method for a dual-mode carrier communication system provided in some embodiments of the present invention. For example... Figure 1 As shown, the HRF signal synchronization method of the dual-mode carrier communication system includes steps 110 to 140.

[0049] Step 110: Based on the maximum allowable residual frequency offset range, divide the frequency offset range into several frequency offset hypothesis intervals, with each frequency offset hypothesis interval corresponding to a frequency offset hypothesis.

[0050] In practical communication, due to frequency errors in the local oscillators at the transmitting and receiving ends, as well as the influence of the Doppler effect in the channel, the received signal will have a certain frequency offset. To eliminate the impact of frequency offset on frame synchronization, this embodiment of the invention divides the maximum allowed residual frequency offset range in the communication protocol into several equally spaced or unequally spaced frequency offset assumption intervals. Each frequency offset assumption interval corresponds to a specific frequency offset assumption value, and the receiving end will subsequently perform pre-compensation based on these assumption values ​​one by one. The maximum allowed residual frequency offset range can be, for example, the frequency offset range determined according to the power communication protocol, or the frequency offset range determined according to the chip performance design requirements; this application does not limit this.

[0051] A communication protocol is a standard or specification defined to enable communication between a receiver and a transmitter in wireless communication. It specifies the data format, transmission rate, synchronization method, etc. The maximum residual frequency offset range is the maximum possible range of frequency deviation between the received and transmitted signals allowed by the communication protocol; it is an important indicator of signal frequency stability. The maximum residual frequency offset range is divided into multiple sub-ranges according to certain rules; each sub-range is called the frequency offset assumption interval.

[0052] Based on this, a specific frequency offset value is set for each frequency offset assumption interval, which serves as the reference benchmark for frequency offset compensation within that interval. This value is called the frequency offset assumption.

[0053] Specifically, the receiving end divides the maximum allowed residual frequency offset range into multiple frequency offset assumption intervals based on the communication protocol. Then, the receiving end sets a corresponding frequency offset assumption for each frequency offset assumption interval. The frequency offset assumption can be set based on the frequency offset interval value corresponding to the frequency offset assumption interval, or it can be set for each frequency offset assumption interval according to a preset calculation rule.

[0054] For example, assuming that the maximum residual frequency offset range allowed by the current communication protocol is [-K, K], and this maximum residual frequency offset range is divided into N frequency offset assumption intervals, then the frequency offset assumption value corresponding to each frequency offset assumption interval can be, for example, 2K / N.

[0055] Step 120: Perform frequency offset pre-compensation on the received signal according to each frequency offset assumption interval to obtain multiple frequency offset compensation signals.

[0056] The frequency offset assumption assumes a carrier frequency offset between the transmitter and receiver. Due to jitter generated by the local oscillators at the transmitter and receiver, such as temperature changes and equipment hardware factors, frequency deviations occur, or the Doppler effect in the wireless channel, resulting in a certain frequency offset of the received signal relative to the local reference frequency.

[0057] Frequency offset pre-compensation is a process in which the frequency offset of the received signal is pre-corrected according to a preset frequency offset assumption before the signal is processed in the next step. Its purpose is to counteract the influence of frequency offset on the signal. After frequency offset pre-compensation with different frequency offset assumptions, multiple sets of corrected signals are obtained, and each set of signals corresponds to a frequency offset assumption.

[0058] Specifically, the receiving end performs pre-compensation processing on the frequency offset of the received signal for each defined frequency offset assumption interval, and finally obtains multiple signals after frequency offset compensation.

[0059] For example, frequency offset compensation may involve applying reverse phase rotation or frequency shift processing to the received signal based on the frequency offset assumption values ​​corresponding to each frequency offset assumption interval.

[0060] Step 130: Perform cross-correlation processing on the multiple frequency offset compensation signals with the local reference sequence to obtain a multi-channel cross-correlation value sequence.

[0061] Cross-correlation processing refers to the mathematical operation used to measure the correlation between the local reference sequence and the frequency offset compensation signal. By calculating the integral of the product of the local reference sequence and the frequency offset compensation signal or by summing them, a result reflecting the degree of similarity between the two is obtained.

[0062] A local reference sequence is a reference sequence that is pre-stored at the receiver of a wireless signal and is completely consistent with a known deterministic sequence sent by the transmitter. It is used to compare with the received signal to achieve functions such as synchronization and matching of wireless signals.

[0063] For each frequency offset compensation signal, the receiver sequentially extracts the sampling segments used for cross-correlation calculation from the sampling point sequence of the signal and performs point-by-point operations with the pre-stored local reference sequence. For example, for the current sampling point position, the sampling points of the same length as the local reference sequence in the compensation signal are first extracted sequentially as a segment of sampling data; then, the values ​​of each sampling point in this segment of sampling data are multiplied point-by-point in the complex field with the corresponding sampling point values ​​in the local reference sequence, and all products are accumulated to obtain the cross-correlation value corresponding to the sampling point position.

[0064] As the sampling point position slides, the above processing procedure is repeated to generate a set of cross-correlation values ​​that vary with the sampling point position across the entire frequency offset compensation signal range, forming a cross-correlation value sequence. By performing the above processing on all frequency offset compensation signals, multiple cross-correlation value sequences corresponding to different frequency offset assumptions can be obtained for subsequent autocorrelation calculations.

[0065] Step 140: In any cross-correlation value sequence, perform autocorrelation processing on the cross-correlation values ​​of adjacent symbol intervals to obtain the corresponding autocorrelation sequence.

[0066] In a communication system, the time interval between two consecutive symbols, that is, the basic signal units that carry wireless signal information, is called the adjacent symbol interval.

[0067] In the obtained cross-correlation value sequence, the receiver performs autocorrelation operations within the interval between adjacent symbols, further enhancing the distinction between the synchronization peak signal and noise by utilizing the repetition between symbols. For example, for the current sampling point position, the cross-correlation value corresponding to that position is first selected, and simultaneously, a cross-correlation value separated from it by one symbol length is selected to form a pair of cross-correlation values; then, this pair of cross-correlation values ​​is multiplied point by point in the complex domain, and the result is used as the autocorrelation value corresponding to that sampling point position. As the sampling point position slides, the above process is repeated, and an autocorrelation sequence that varies with the sampling point position can be obtained over the entire cross-correlation value sequence. This autocorrelation sequence can amplify the periodic correlation between cross-correlation values, resulting in a more prominent and stable peak under frequency offset compensation conditions.

[0068] By performing the above autocorrelation calculation on the cross-correlation value sequences obtained under different frequency offset assumptions, a multi-channel autocorrelation sequence corresponding to each frequency offset assumption can be obtained, providing a basis for subsequent correlation peak extraction and synchronization position determination.

[0069] For example, Figure 2 This is a schematic diagram illustrating the autocorrelation processing of multi-channel frequency offset compensation signals after cross-correlation processing, as provided in some embodiments of the present invention. For example... Figure 2 As shown, the sequence consisting of S and -S at the top is the signal sequence. In the cross-correlation section, the arrows indicate the signs of the cross-correlation values ​​obtained after cross-correlation processing of the multiple frequency offset compensation signals with the local reference sequence. When the arrow points downwards, it indicates a negative cross-correlation value. In the autocorrelation section below, the curve performs autocorrelation processing on the multiple cross-correlation values ​​within the interval between adjacent symbols, reflecting the matching of signals after autocorrelation processing under different frequency offset assumptions. 0 and 1 represent the autocorrelation processing signs. "0" indicates a negative autocorrelation value, which needs to be converted to a positive value (e.g., multiplied by -1) before accumulation. Conversely, "1" indicates a positive autocorrelation value, which can be directly accumulated. This method eliminates the interference of positive and negative signs during accumulation, resulting in a more pronounced peak in the final accumulation result.

[0070] Step 150: Extract the correlation peaks corresponding to each frequency offset hypothesis from the multi-path autocorrelation sequences, and determine the maximum correlation peak.

[0071] After processing the autocorrelation of the multiple cross-correlation value sequences, the receiver obtains multiple autocorrelation sequences corresponding to different frequency offset hypotheses. In each autocorrelation sequence, the receiver detects and extracts the point with the largest amplitude as the correlation peak corresponding to that frequency offset hypothesis.

[0072] After extracting the peak values ​​from all autocorrelation sequences, the receiver aggregates the correlation peak values ​​obtained under different frequency offset assumptions, compares their amplitudes, and selects the correlation peak value with the largest amplitude as the final result. This largest correlation peak value is then output for use in subsequent synchronization determination steps.

[0073] In this way, the receiver can accurately lock the optimal correlation peak from multiple frequency offset hypothesis candidate results, which not only enhances the identifiability of the synchronization peak, but also provides reliable input for the accurate determination of the subsequent synchronization position.

[0074] Step 160: If the maximum correlation peak value is greater than the synchronization determination threshold, determine the position corresponding to the maximum correlation peak value as the synchronization position.

[0075] After extracting the correlation peaks under multiple frequency offset assumptions and determining the largest correlation peak, the receiver compares the largest correlation peak with a preset synchronization determination threshold. If the amplitude of the largest correlation peak exceeds the preset synchronization determination threshold, the detected peak is considered to have sufficient reliability, and its corresponding position is determined as the synchronization position of the wireless signal frame.

[0076] In practical applications, the synchronization judgment threshold can be set based on experimental data or protocol standards. Its function is to distinguish between the real synchronization peak and the pseudo peak generated by noise interference, thereby avoiding erroneous synchronization in low signal-to-noise ratio environments.

[0077] Simultaneously, the frequency offset assumption corresponding to the relevant peak value is determined as the effective frequency offset assumption for use in subsequent demodulation processes. This effective frequency offset assumption corresponds to specific frequency offset compensation parameters and can be directly applied to the received data after the synchronization position, thereby completing the frequency offset correction of the entire frame signal. In this way, the receiver can obtain the optimal frequency offset compensation reference while locking the synchronization position, so that subsequent symbol demodulation and channel processing can be performed under conditions of small residual frequency offset, avoiding the problem of inaccurate subsequent data processing due to excessive frequency offset. Therefore, this embodiment of the invention not only achieves accurate detection of the frame start position but also provides a reliable frequency offset compensation basis for the subsequent demodulation process, ensuring the stability and demodulation performance of the communication system under complex channel conditions.

[0078] By using the above method, the most reliable synchronization point can be found among the candidate results of various frequency offset hypotheses, effectively avoiding peak offset or detection failure caused by residual frequency offset, and ensuring synchronization accuracy and system stability under complex channel conditions.

[0079] The HRF signal synchronization method for a dual-mode carrier communication system provided in this invention divides the maximum allowed residual frequency offset in the communication protocol into several frequency offset assumption intervals, providing a compensation benchmark for different frequency offset scenarios. This avoids the failure of a single compensation due to an excessively large frequency offset range and reduces invalid compensation. By performing frequency offset pre-compensation on the received signal according to each frequency offset assumption interval, multiple frequency offset compensation signals are obtained, covering the entire residual frequency offset range allowed by the communication protocol. For any unknown frequency offset, the impact of frequency offset can be effectively reduced, providing high-quality input for subsequent correlation processing. For the pre-compensated signal, cross-correlation processing is first performed on the multiple frequency offset compensation signals, and then autocorrelation is performed on the cross-correlation results. This achieves an organic combination of cross-correlation and autocorrelation, enabling the further superposition of signal energy on the multiple cross-correlation value sequences when there are few sampling points in the short training sequence, thereby significantly improving the amplitude of the correlation peak. Compared to a single autocorrelation or cross-correlation method, this invention can generate more obvious peak characteristics, improve the accuracy of determining the synchronization position in low signal-to-noise ratio environments, accurately find the synchronization position in low signal-to-noise ratio and frequency offset interference environments, improve the robustness and reliability of synchronization detection, and ensure the stable operation of the dual-mode carrier communication system under complex channel conditions.

[0080] In scenarios where the maximum residual frequency offset range allowed by the communication protocol is wide, if a specific strategy is not adopted to pre-compensate the received signal for frequency offset using a preset frequency offset assumption, a single compensation strategy will be difficult to cover all frequency offset situations, resulting in insufficient signal synchronization accuracy.

[0081] Based on this, in some embodiments, frequency offset pre-compensation is performed on the received signal according to each frequency offset assumption interval to obtain multiple frequency offset compensation signals. Specifically, this includes: determining the center frequency of each frequency offset assumption interval and generating corresponding frequency offset compensation coefficients based on the center frequency; and performing reverse phase rotation compensation on the received signal according to each frequency offset compensation coefficient to obtain multiple frequency offset compensation signals corresponding to each frequency offset assumption.

[0082] It should be noted that the center frequency is the midpoint frequency of each frequency offset assumption interval, serving as the reference frequency for frequency offset compensation within that interval; the frequency offset compensation coefficient is a parameter calculated based on the center frequency of the frequency offset assumption interval, used to quantify the amplitude of the reverse phase rotation, and is the core numerical basis for realizing frequency offset compensation.

[0083] Reverse phase rotation compensation refers to a processing method that applies phase adjustment to the received signal in the opposite direction to the phase change caused by the frequency offset, based on the frequency offset compensation coefficient, in order to counteract the phase distortion caused by the frequency offset.

[0084] Specifically, the receiver first calculates and determines the center frequency for each predefined frequency offset assumption interval. Then, using this center frequency as a reference, it generates a frequency offset compensation coefficient specific to each interval through quantization calculation of the signal phase characteristics. Subsequently, the receiver maps the received signal to each frequency offset compensation coefficient one by one, and performs targeted frequency offset pre-compensation by applying a phase rotation process to the received signal that is opposite to the phase offset direction introduced by the frequency offset. Finally, it outputs a multi-channel frequency offset compensation signal that matches each frequency offset assumption.

[0085] For example, if the maximum permissible residual frequency offset range in the HRF communication protocol is ±25kHz, and this continuous frequency offset range of ±25kHz is divided into 5 assumed frequency offset intervals, each with a bandwidth of 10kHz (±5kHz), then the range of each interval is [-25kHz, -15kHz], [-15kHz, -5kHz], [-5kHz, +5kHz], [+5kHz, +15kHz], and [+15kHz, +25kHz]. The calculated center frequencies for each of these intervals are then -20kHz, -10kHz, 0kHz, +10kHz, and +20kHz.

[0086] Taking Orthogonal Frequency Division Multiplexing (OFDM) signals as an example, let the received signal sequence be... For OFDM signals, The received signal of each subcarrier can be represented as:

[0087] (1)

[0088] in, Indicates time, It is the first The amplitude of each subcarrier signal, Represents the imaginary unit. Indicates the first The frequency of each subcarrier This represents the actual frequency offset value. It is a complex exponential term. And the frequency offset... The resulting phase rotation is .

[0089] At this point, the continuous frequency offset range is equally divided into 5 assumed frequency offset intervals, representing 5 channels and compensation values. Let... Indicates the firsti The compensation value of the road, and at this time the compensation value is the center frequency corresponding to each interval, can be known. , , , and The frequency offset compensation coefficient is calculated using the following formula. :

[0090] (2)

[0091] Let for the th Received signal of each subcarrier , No. The signal after road compensation is as follows:

[0092] (3)

[0093] Substitution After that, the first one can be obtained. The signal after road compensation is as follows:

[0094] (4)

[0095] In the above embodiments, by using the center frequency as a reference, the continuously distributed frequency offset range is discretized into several quantifiable compensation references. The compensation coefficients generated based on the center frequency can specifically eliminate the phase error under each assumed frequency offset, thereby improving the compensation accuracy. In the frequency offset pre-compensation stage, the phase distortion caused by the assumed frequency offset is eliminated, and the peak values ​​of subsequent cross-correlation and autocorrelation are more concentrated and obvious, improving the synchronization performance under low signal-to-noise ratio. Under multiple assumptions, the compensated signal is closer to the state without frequency offset, and the effective frequency offset assumption that is closest to the actual frequency offset can be found more accurately, thereby improving the synchronization accuracy.

[0096] In wireless communication systems, the transmitting end typically predetermines a known local reference sequence and embeds it into the transmitted signal. The signal received by the receiving end contains the target signal and noise or interference. The target signal is strongly correlated with the local reference sequence, while the noise or interference is weakly or uncorrelated with it. Without proper processing, the receiving end will be unable to effectively identify the target signal from the mixed signal, and the noise and interference will directly enter the subsequent decoding stage.

[0097] Based on this, in some embodiments, the multiple frequency offset compensation signals are cross-correlated with the local reference sequence to obtain a multi-channel cross-correlation value sequence. Specifically, this includes: for any frequency offset compensation signal, extracting a sampling point sequence with the same length as the local reference sequence within a sliding window; multiplying the sampling point sequence with the signal values ​​of the corresponding sampling points in the local reference sequence point by point in the complex domain and accumulating the results to obtain the cross-correlation value corresponding to the current window position; and repeating the above process as the sliding window moves over the targeted frequency offset compensation signal to form the cross-correlation value sequence corresponding to the targeted frequency offset compensation signal.

[0098] After receiving multiple frequency offset compensation signals, the receiver performs cross-correlation calculations on each signal. Specifically, the receiver first sets a sliding window on the frequency offset compensation signal, the length of which is the same as the length of the local reference sequence.

[0099] When the window is at its current starting position, the sampling point sequence within the window range is extracted from the frequency offset compensation signal. Then, the sampling point value in the sampling point sequence is multiplied point by point in the complex domain with the sampling point value at the corresponding position in the local reference sequence, and all products are accumulated to obtain the cross-correlation value corresponding to the starting position of the current window.

[0100] As the sliding window moves point by point on the frequency offset compensation signal, the above calculation process is repeated to obtain the cross-correlation values ​​corresponding to different window positions in sequence. These cross-correlation values ​​are then arranged in order of window position to form a cross-correlation value sequence corresponding to the frequency offset compensation signal.

[0101] By performing the above processing on all frequency offset compensation signals respectively, the receiver can generate a multi-channel cross-correlation value sequence corresponding to different frequency offset assumptions, providing input for subsequent autocorrelation calculations and synchronization determination.

[0102] For example, in one specific implementation, assuming the short training symbol S has a length of 4 sampling points, the local reference sequence also consists of 4 sampling points, namely b1, b2, b3, and b4. If the compensated received signals are a1, a2, a3, a4, a5, and a6 in sequence, then when performing cross-correlation calculations:

[0103] For sampling point a6, its cross-correlation value is obtained by multiplying the local reference sequences b1 to b4 with the sampling points a3 to a6 in the received signal point by point and then summing them up.

[0104] For sampling point a5, its cross-correlation value is obtained by multiplying the local reference sequences b1 to b4 with the sampling points a2 to a5 in the received signal point by point and then summing them up.

[0105] For any sampling point an, its cross-correlation value is obtained by multiplying the local reference sequence b1 to b4 with the sampling points a(n-3) to an in the received signal point by point and then summing them.

[0106] Using the above calculation method, a sliding window can be applied point-by-point on the received signal to obtain the cross-correlation values ​​corresponding to each sampling point, ultimately forming a cross-correlation value sequence. This cross-correlation value sequence reflects the degree of matching between the received signal and the local reference sequence at different locations, providing input for subsequent autocorrelation processing and synchronization position detection.

[0107] In the above embodiments, by using the cross-correlation calculation method with a sliding window, it is possible to extract the sampling segments that match the local reference sequence point by point in the received signal, and multiply and accumulate them point by point in the complex domain to form a continuous cross-correlation value sequence. Compared with performing a single cross-correlation operation at a fixed position, it can more comprehensively reflect the degree of matching between the received signal and the local reference sequence at different sampling point positions.

[0108] Furthermore, the cross-correlation value sequence can intuitively show the change of signal matching degree with time position, making the synchronization peak appear as a prominent and identifiable maximum point in the sequence, thereby improving the accuracy and robustness of subsequent frame start position detection. In addition, since the cross-correlation value sequence retains the point-by-point correlation characteristics of the signal, it has a stronger resistance to noise interference and can maintain a high peak contrast even under low signal-to-noise ratio conditions, improving the stability of the entire synchronization process.

[0109] After obtaining the cross-correlation value between each frequency offset compensation signal and the local reference sequence, although the cross-correlation value itself can reflect the matching degree between the compensation signal and the reference sequence, in environments with low signal-to-noise ratios or strong interference, the difference between noise and signal is not obvious, and the cross-correlation result may still have fluctuations caused by noise interference, resulting in insufficiently prominent correlation peaks. Furthermore, the setting of the frequency offset assumption may be random with the wireless signal, making the cross-correlation value relatively weak. In such cases, directly using the cross-correlation value for frame synchronization decision can easily lead to peak misjudgment, thereby reducing synchronization accuracy.

[0110] To address this issue, this invention proposes an improved scheme in some embodiments: after obtaining the multi-path cross-correlation values, the periodicity of symbols in the short training field is fully utilized to perform autocorrelation processing on the cross-correlation values ​​within the interval between adjacent symbols, thereby generating autocorrelation peaks corresponding to each frequency offset hypothesis. This method can effectively suppress the influence of random noise, making the correlation peaks more significant, thus improving the reliability of frame synchronization.

[0111] Therefore, in some embodiments, autocorrelation processing is performed on the multi-path cross-correlation values ​​within the adjacent symbol interval to generate correlation peaks corresponding to each frequency offset hypothesis. Specifically, this includes: for the cross-correlation value corresponding to any frequency offset compensation signal, selecting the cross-correlation value of the current sampling point and the cross-correlation value with a preset symbol length interval within the adjacent symbol interval to form a cross-correlation value pair for autocorrelation processing; and multiplying each cross-correlation value pair one by one to obtain the autocorrelation value sequence under the frequency offset hypothesis corresponding to the frequency offset compensation signal.

[0112] The preset symbol length is the symbol period length predetermined according to the communication protocol or signal structure, which is the fixed time interval reference for selecting cross-correlation value pairs. The combination of two cross-correlation values ​​selected at a preset symbol length interval for performing autocorrelation processing is called a cross-correlation value pair. The ordered set of data formed by arranging the results of multiplying all cross-correlation value pairs in sequence is the autocorrelation value sequence.

[0113] Specifically, for each cross-correlation value corresponding to the frequency offset compensation signal, the receiver finds the cross-correlation value of another sampling point separated from the current sampling point by a preset symbol length for each current sampling point in the cross-correlation value. The two cross-correlation values ​​are combined to form a cross-correlation value pair for subsequent autocorrelation processing. A multiplication operation is performed on each pair of cross-correlation values. The multiplication results of all cross-correlation value pairs are arranged in order according to their corresponding sampling points to construct an ordered data sequence, which serves as the autocorrelation value sequence under the frequency offset assumption corresponding to the frequency offset compensation signal.

[0114] In the above embodiments, by extracting peak values ​​through autocorrelation sequences, reliable synchronization criteria can be obtained under different frequency offset assumptions, thereby improving the accuracy and anti-interference capability of frame start position detection. In particular, by selecting cross-correlation value pairs within the interval between adjacent symbols for autocorrelation processing, the repetitive characteristics of short training fields are effectively utilized to improve the significance of autocorrelation peak values.

[0115] After obtaining multiple autocorrelation value sequences corresponding to each frequency offset hypothesis, the receiver can select the data point with the largest value. The data point with the largest value can intuitively reflect the location where the signal energy is most concentrated in the sequence. The receiver determines this as the correlation peak value under the corresponding frequency offset hypothesis for that frequency offset compensation signal, which is used to measure the effectiveness of the frequency offset hypothesis. The receiver applies the above operation to the cross-correlation values ​​corresponding to all frequency offset compensation signals, and through processing them one by one, finally obtains the correlation peak value corresponding to each frequency offset hypothesis.

[0116] Among them, the correlation peak is the point with the largest value in the autocorrelation sequence, at which point the periodicity and matching degree of the signal are optimal under the frequency offset assumption.

[0117] In traditional wireless signal synchronization methods, autocorrelation values ​​are typically extracted based on a single adjacent symbol interval to detect correlation peaks. However, in power line carrier communication environments, factors such as frequency offset, channel fading, and noise interference exist. The autocorrelation results of a single interval are easily affected by noise in low signal-to-noise ratio scenarios, resulting in indistinct or even masked autocorrelation peaks.

[0118] Although autocorrelation processing can effectively increase the energy of the effective signal, it is still easily affected by sudden noise interference, such as transient electromagnetic pulses and channel fading, in wireless communication environments with strong interference, thus affecting stability. Furthermore, the periodicity of signals with OFDM modulation may fluctuate due to inter-carrier interference, and the autocorrelation value of a single interval may not be able to fully reflect its periodicity.

[0119] Based on this, in some embodiments, corresponding autocorrelation values ​​are extracted based on multiple different adjacent symbol intervals to form a cross-interval autocorrelation value set. Multiple autocorrelation values ​​belonging to the same frequency offset hypothesis within the autocorrelation value set are then incoherently superimposed to accumulate the amplitudes of their respective autocorrelation values, obtaining the enhanced correlation peak under the corresponding frequency offset hypothesis. This peak is then used as input to determine the maximum correlation peak in subsequent steps. This effectively improves the distinction between peak values ​​and noise, thereby enhancing synchronization performance.

[0120] It should be noted that the set of autocorrelation values ​​across intervals is a set of overall data composed of autocorrelation values ​​extracted from multiple different adjacent symbol intervals; incoherent superposition refers to a superposition method that only accumulates the amplitude of the signal without considering phase information, which can avoid energy cancellation caused by phase differences.

[0121] Specifically, the receiver first extracts the autocorrelation value corresponding to each interval, and then classifies all the extracted autocorrelation values ​​according to the frequency offset hypothesis category to construct a set of autocorrelation values ​​that spans multiple intervals.

[0122] Following this, the receiver analyzes the set of autocorrelation values. For multiple autocorrelation values ​​belonging to the same frequency offset hypothesis, an incoherent superposition method is used to accumulate the amplitudes of the multiple autocorrelation values. For example, the receiver takes the absolute value of each autocorrelation value and accumulates them one by one to obtain the enhanced correlation peak under the corresponding frequency offset hypothesis. Since the amplitudes are directly superimposed without phase compensation, there is no need to assume phase consistency. The receiver repeats the above process for all frequency offset hypotheses to obtain a set of enhanced correlation peak sequences, which serve as inputs for determining the maximum correlation peak and the optimal frequency offset hypothesis in subsequent steps. Finally, the receiver organizes the enhanced correlation peaks obtained after processing all frequency offset hypotheses to form a complete peak data set, which is used as input for determining the maximum correlation peak in subsequent steps.

[0123] In the above embodiments, autocorrelation values ​​are extracted based on multiple adjacent symbol intervals, making more comprehensive use of the repetition of symbols in the short training field and increasing the amount of synchronization feature information. By integrating autocorrelation values ​​across intervals and performing incoherent superposition, the effective signal energy under the same frequency offset hypothesis is enhanced, effectively suppressing noise interference. The energy and stability of the signal are improved based on the autocorrelation peak of a single interval. As a result, the enhanced correlation peak is more obvious, making it more reliable in determining the maximum correlation peak and the optimal frequency offset hypothesis, and reducing the synchronization misjudgment rate.

[0124] In the process of incoherently superimposing multiple autocorrelation values ​​belonging to the same frequency offset hypothesis in the autocorrelation value set, if complex autocorrelation values ​​containing phase are directly superimposed, the effective energy will be canceled due to phase disorder; if they are not accumulated according to time, the periodicity of the signal will be destroyed, the energy of the signal will be dispersed, and ultimately the effective and invalid frequency offset hypotheses cannot be distinguished in low signal-to-noise ratio scenarios, thus reducing the accuracy of frequency offset estimation.

[0125] Therefore, in some embodiments, multiple autocorrelation values ​​belonging to the same frequency offset hypothesis in the autocorrelation value set are incoherently superimposed to accumulate the amplitudes of their respective autocorrelation values ​​to obtain the enhanced correlation peak under the corresponding frequency offset hypothesis. Specifically, it also includes: extracting the corresponding amplitude information for each autocorrelation value belonging to the same frequency offset hypothesis in the autocorrelation value set to form an amplitude sequence; and accumulating the amplitude sequence item by item at multiple adjacent symbol intervals according to the time position correspondence to obtain the enhanced correlation peak under the corresponding frequency offset hypothesis.

[0126] Before performing incoherent superposition, the receiver extracts the amplitude information of the respective correlation values ​​belonging to the same frequency offset hypothesis and forms a corresponding amplitude sequence. Then, according to the correspondence of time positions, the sequence is accumulated item by item at multiple adjacent symbol intervals to ensure that the autocorrelation amplitude at the same time point can be concentrated and enhanced, thereby obtaining the enhanced correlation peak under the frequency offset hypothesis.

[0127] Specifically, the receiver first selects multiple autocorrelation values ​​belonging to the same frequency offset hypothesis from the set of autocorrelation values. For these selected autocorrelation values, the amplitude information contained in each autocorrelation value is extracted, and these amplitude information are arranged sequentially according to the time order corresponding to the autocorrelation values ​​to form an ordered amplitude sequence.

[0128] The amplitude values ​​in the amplitude sequence are arranged in the order of the time sampling points to ensure that the amplitude values ​​at the same time position under different symbol intervals can correspond one-to-one during accumulation, avoiding erroneous accumulation across time points.

[0129] Within a range of multiple adjacent symbol intervals, the receiver finds amplitude values ​​at the same time position (i.e., corresponding to the same sampling point) in the amplitude sequence, and performs an accumulation operation on these amplitude values ​​at the same position one by one. Finally, the result obtained after accumulation processing is the enhanced correlation peak under this frequency offset assumption.

[0130] For each time point, the accumulated results reflect the combined effect of the autocorrelation amplitudes across all intervals. Ultimately, significant synchronization peaks can be identified more accurately in the enhanced correlation peak sequence.

[0131] In the above embodiments, by accumulating the amplitudes of autocorrelation values, the effective signal energy at corresponding time positions in different intervals under the same frequency offset assumption is superimposed and enhanced, while the energy of random noise cancels each other out due to its disordered distribution. This results in higher energy and stronger stability of the wireless signal, and a clearer reflection of the degree of matching between the frequency offset assumption and the actual signal frequency offset. The enhanced correlation peak sequence is more concentrated and obvious, making the determination of the synchronization position of subsequent frames more reliable and reducing the false positive rate.

[0132] In the process of inferring the effective frequency offset hypothesis based on the determined maximum correlation peak, when the channel noise is strong, the random superposition of noise may produce a false peak higher than the effective signal peak. If no effective selection measures are taken, the false frequency offset hypothesis corresponding to the noise may be misjudged as the effective hypothesis, resulting in subsequent synchronization operations based on the wrong frequency offset parameters.

[0133] In response to this, in some embodiments, the effective frequency offset hypothesis corresponding to the maximum correlation peak is determined, and the maximum correlation peak is compared with a preset synchronization determination threshold. When the maximum correlation peak is greater than the synchronization determination threshold, the frequency offset hypothesis corresponding to the maximum correlation peak is determined to be the effective frequency offset hypothesis.

[0134] It should be noted that the preset synchronization judgment threshold is a numerical standard set by the receiver in advance based on the channel environment, signal characteristics, etc., used to distinguish the relevant peak value corresponding to the valid signal from the false peak value caused by noise interference.

[0135] In other words, when determining the effective frequency offset hypothesis, the receiver first determines the maximum value among all relevant peak values, i.e., the maximum correlation peak value. The magnitude of this peak value directly corresponds to the degree of matching between its corresponding frequency offset hypothesis and the actual frequency offset of the received signal. The larger the peak value, the higher the degree of matching. The frequency offset hypothesis corresponding to this maximum correlation peak value is directly assigned. This method is suitable for cases where the peak values ​​are significant and stable, and it is computationally simple and efficient.

[0136] In complex wireless signal transmission environments, to avoid misjudgments caused by noise, the effective frequency offset hypothesis selection method can be as follows: The receiver first filters out the largest correlation peak from all correlation peaks, and simultaneously reads the synchronization judgment threshold in the device. The largest correlation peak is then compared numerically with the synchronization judgment threshold. If the value of the largest correlation peak is greater than or equal to the synchronization judgment threshold, it indicates that the frequency offset hypothesis corresponding to that peak not only has the highest matching degree but also sufficient signal energy to exclude the influence of noise interference, thus possessing effectiveness. In this case, the receiver determines the frequency offset hypothesis corresponding to the largest correlation peak as an effective frequency offset hypothesis. Conversely, if the value is less than or equal to the threshold, it indicates that the matching degree of the frequency offset hypothesis corresponding to the largest correlation peak is low, and it may not be able to exclude the influence of noise interference. This method is suitable for low signal-to-noise ratio environments or situations with significant channel interference, and can reduce the probability of false locking.

[0137] In the above embodiments, by setting different methods for determining effective frequency offset assumptions, for wireless signals with good transmission environments, the frequency offset assumption corresponding to the maximum correlation peak is directly determined as the effective assumption. The operation is simple, efficient, and has high real-time performance. For wireless signals with more complex transmission environments, by setting a synchronization judgment threshold, false peaks caused by noise interference can be effectively filtered out, avoiding misjudgment and improving the reliability of the determination of effective frequency offset assumptions. The use of both methods, while taking into account processing efficiency, can quickly lock the optimal frequency offset in high signal-to-noise ratio environments and improve the robustness of synchronization judgment in low signal-to-noise ratio scenarios, thus balancing efficiency and reliability.

[0138] In traditional multi-frequency offset hypothesis synchronization methods, the frequency offset hypothesis interval is typically statically divided according to the maximum residual frequency offset range specified by the communication protocol. However, statically divided intervals cannot adaptively adjust to changes in received signal quality, leading to an imbalance between computational efficiency and reliability. When signal stability is high, the actual frequency offset is usually small and has a narrow fluctuation range. If too many frequency offset hypotheses are calculated, it will prolong the determination time of the effective frequency offset hypothesis. When signal stability is poor, the actual frequency offset may fluctuate more significantly and over a wider range due to noise superposition, which may not be able to cover the wide frequency offset fluctuations caused by noise interference. As a result, the hypothesis corresponding to the true frequency offset is not included in the interval, making it impossible for the receiver to find a matching effective frequency offset hypothesis.

[0139] Based on this, in some embodiments, the frequency offset assumption interval is dynamically adjusted based on the signal characteristics of the received signal, which include at least the signal-to-noise ratio (SNR); wherein, the range of the frequency offset assumption interval is reduced under high SNR conditions and expanded under low SNR conditions.

[0140] High signal-to-noise ratio (SNR) refers to the situation where the SNR of the received signal is greater than a preset high SNR threshold. In this case, the received signal energy is significantly higher than the noise energy, the signal waveform characteristics are clear, the correlation peaks are prominent, and the reliability of frequency offset estimation and frame synchronization is high.

[0141] Low signal-to-noise ratio (SNR) refers to a situation where the SNR of the received signal is lower than a preset low SNR threshold. In this case, the noise energy is equal to or even higher than the signal energy, the received signal waveform is severely distorted, and relevant peaks are submerged in noise, leading to a decrease in synchronization performance.

[0142] Specifically, the receiving end first analyzes and processes the received signal to extract characteristic parameters that reflect the signal attributes. These characteristic parameters include at least the signal-to-noise ratio.

[0143] After acquiring signal characteristics, the receiver dynamically adjusts the frequency offset hypothesis interval based on these characteristics. Taking signal-to-noise ratio (SNR) as an example, the receiver first determines the current SNR condition of the received signal. If it determines that the received signal is in a high SNR state, that is, the effective signal energy is significantly higher than the noise energy and the signal is less affected by interference, then the coverage of the frequency offset hypothesis interval is reduced, and the number of frequency offset hypotheses included in the interval is reduced, thereby reducing the complexity of cross-correlation and autocorrelation calculations.

[0144] If the received signal is determined to be in a low signal-to-noise ratio state, that is, the effective signal energy is close to or lower than the noise energy, the signal is highly interfered with, the channel environment is harsh, and the noise interference is large, the receiver will expand the coverage of the frequency offset assumption interval and increase the number of frequency offset assumptions included in the interval to ensure that the actual frequency offset can be covered, thereby improving the synchronization success rate.

[0145] After the frequency offset assumption interval range is dynamically adjusted, the receiver can also re-divide each frequency offset assumption interval and generate an updated frequency offset assumption set for subsequent frequency offset pre-compensation, cross-correlation calculation and autocorrelation peak extraction.

[0146] In the above embodiments, by dynamically adjusting the frequency offset assumption range based on the signal characteristics of the received signal, the frequency offset assumption can be applied to the needs of various communication scenarios, can cover the wide frequency offset fluctuation range caused by noise interference relatively completely, avoids omitting the assumption corresponding to the real frequency offset, ensures the integrity and reliability of the frequency offset estimation, and solves the synchronization failure problem under complex channels.

[0147] The processing procedure of the intermediate frequency offset compensation signal in this invention will be described below with reference to the accompanying drawings.

[0148] Figure 3 This is a schematic diagram of multi-channel frequency offset compensation signal processing provided in some embodiments of the present invention. For example... Figure 3As shown, the topmost part is the signal sequence to be processed, containing two values: S and -S. The arrows indicate the participation of signals at different locations in the correlation operation. The "Cross-correlation" section presents the cross-correlation results between the signal and the reference sequence. The arrow direction reflects the positive or negative characteristics of the correlation value, used to initially determine the degree of matching between the signals. "Autocorrelation 1" is the autocorrelation operation performed after the wireless signal has undergone cross-correlation, while "Autocorrelation 2" represents the incoherent superposition process. "0" indicates that the autocorrelation is negative at this point, and it needs to be converted to a positive value (e.g., multiplied by -1) before accumulation. Conversely, "1" indicates that the autocorrelation is positive at this point, and autocorrelation superposition can be performed directly. In this way, the interference of positive and negative signs can be eliminated during the accumulation process, resulting in a more obvious peak in the final accumulation result.

[0149] Figure 4 This is a schematic diagram of an HRF signal synchronization method for a dual-mode carrier communication system provided in some embodiments of the present invention. For example... Figure 4 As shown, the input sequence is first processed in five paths, with each path pre-compensating for different frequency offsets. These frequency offsets are set to -20 kHz, -10 kHz, 0 kHz, +10 kHz, and +20 kHz, respectively. Next, each pre-compensated signal undergoes cross-correlation and autocorrelation calculations. The results from all paths are compared, and the maximum value of the correlation peak is identified to determine the best-matching frequency offset compensation.

[0150] The HRF signal synchronization method for a dual-mode carrier communication system provided in this embodiment of the invention can be executed by a dual-mode carrier communication system HRF signal synchronization device. This embodiment of the invention uses the execution of the dual-mode carrier communication system HRF signal synchronization method by the dual-mode carrier communication system HRF signal synchronization device as an example to illustrate the dual-mode carrier communication system HRF signal synchronization device provided in this embodiment of the invention.

[0151] This invention also provides an HRF signal synchronization device for a dual-mode carrier communication system, applied at the receiving end.

[0152] Figure 5 This is a schematic diagram of the structure of the HRF signal synchronization device for a dual-mode carrier communication system provided in some embodiments of the present invention. For example... Figure 5 As shown, the HRF signal synchronization device of the dual-mode carrier communication system includes a pre-division module 500, a pre-compensation module 501, a cross-correlation module 502, an autocorrelation module 503, and a determination module 504. Wherein:

[0153] The partitioning module 500 is used to divide the frequency offset range into several frequency offset assumption intervals according to the maximum residual frequency offset range allowed in the communication protocol, with each frequency offset assumption interval corresponding to a frequency offset assumption.

[0154] The pre-compensation module 501 is used to perform frequency offset pre-compensation on the received signal according to each frequency offset assumption interval to obtain multiple frequency offset compensation signals.

[0155] The cross-correlation module 502 is used to perform cross-correlation processing on the multi-channel frequency offset compensation signals with the local reference sequence to obtain a multi-channel cross-correlation value sequence.

[0156] The autocorrelation module 503 is used to perform autocorrelation processing on the cross-correlation values ​​of adjacent symbol intervals in any cross-correlation value sequence to obtain the corresponding autocorrelation sequence;

[0157] The determination module 504 is used to extract the correlation peaks corresponding to each frequency offset hypothesis from the multi-channel autocorrelation sequences, and determine the maximum correlation peak from them;

[0158] The determining module 504 is further configured to determine the position corresponding to the maximum correlation peak as the synchronization position when the maximum correlation peak is greater than the synchronization determination threshold.

[0159] The HRF signal synchronization device for a dual-mode carrier communication system provided in this embodiment of the invention divides the maximum allowed residual frequency offset in the communication protocol into several frequency offset assumption intervals, providing a compensation benchmark for different frequency offset scenarios, avoiding the failure of a single compensation due to an excessively large frequency offset range, and reducing invalid compensation. By performing frequency offset pre-compensation on the received signal according to each frequency offset assumption interval, multiple frequency offset compensation signals are obtained, covering the entire residual frequency offset range allowed by the communication protocol. For any unknown frequency offset, the influence of frequency offset can be effectively reduced, providing high-quality input for subsequent correlation processing. For the pre-frequency offset compensated signal, cross-correlation processing is first performed on the multiple frequency offset compensation signals, and then autocorrelation is performed on the cross-correlation results, realizing the organic combination of cross-correlation and autocorrelation. This allows for the further superposition of signal energy on the multiple cross-correlation value sequences when there are few sampling points in the short training sequence, thereby significantly improving the amplitude of the correlation peak. Compared to a single autocorrelation or cross-correlation method, this invention can generate more obvious peak characteristics, improve the accuracy of determining the synchronization position in low signal-to-noise ratio environments, accurately find the synchronization position in low signal-to-noise ratio and frequency offset interference environments, improve the robustness and reliability of synchronization detection, and ensure the stable operation of the dual-mode carrier communication system under complex channel conditions.

[0160] In some embodiments, the pre-compensation module is further configured to determine the center frequency of each frequency offset assumption interval and generate corresponding frequency offset compensation coefficients based on the center frequency; and perform reverse phase rotation compensation on the received signal according to each frequency offset compensation coefficient to obtain a multi-channel frequency offset compensation signal corresponding to each frequency offset assumption.

[0161] In some embodiments, the cross-correlation module is used to extract a sequence of sampling points of the same length as the local reference sequence within a sliding window for any frequency offset compensation signal; multiply the sampling point sequence with the signal values ​​of the corresponding sampling points in the local reference sequence point by point in the complex domain and accumulate them to obtain the cross-correlation value corresponding to the current window position; and repeat the above process as the sliding window moves over the target frequency offset compensation signal to form a cross-correlation value sequence corresponding to the target frequency offset compensation signal.

[0162] In some embodiments, the autocorrelation module is used to select the cross-correlation value of the current sampling point and the cross-correlation value with a preset symbol length interval within the adjacent symbol interval for the cross-correlation value corresponding to any frequency offset compensation signal, forming a cross-correlation value pair for autocorrelation processing; and multiply each of the cross-correlation value pairs one by one to obtain the autocorrelation value sequence under the frequency offset assumption corresponding to the frequency offset compensation signal.

[0163] In some embodiments, the above-described apparatus further includes an enhancement module, configured to extract corresponding autocorrelation values ​​based on multiple different adjacent symbol intervals to form a cross-interval autocorrelation value set; to incoherently superimpose multiple autocorrelation values ​​belonging to the same frequency offset hypothesis in the autocorrelation value set to accumulate the amplitude of each autocorrelation value to obtain the enhanced correlation peak value under the corresponding frequency offset hypothesis, which is used as the input for determining the maximum correlation peak value in subsequent steps.

[0164] In some embodiments, the enhancement module is further configured to extract the corresponding amplitude information for each correlation value belonging to the same frequency offset hypothesis in the autocorrelation value set, and form an amplitude sequence; according to the time position correspondence, the amplitude sequence is accumulated item by item at multiple adjacent symbol intervals to obtain the enhanced correlation peak under the corresponding frequency offset hypothesis.

[0165] The HRF signal synchronization device in the dual-mode carrier communication system of this invention can be a receiver or a component within the receiver, such as an integrated circuit or a chip. The receiver can be a terminal device or a server.

[0166] The HRF signal synchronization device for a wireless signal synchronization dual-mode carrier communication system based on multi-frequency offset assumption provided in this embodiment of the invention can realize the various processes implemented in each method embodiment. To avoid repetition, it will not be described again here.

[0167] Figure 6 This is a schematic diagram of the structure of an electronic device provided in some embodiments of the present invention. In some embodiments, such as... Figure 6As shown, this embodiment of the invention also provides an electronic device 600, including a processor 601, a memory 602, and a computer program stored in the memory 602 and executable on the processor 601. When the program is executed by the processor 601, it implements the various processes of the above-described method embodiments and achieves the same technical effects. To avoid repetition, it will not be described again here.

[0168] It should be noted that the receiving end in the embodiments of the present invention includes the mobile receiving end and the non-mobile receiving end described above.

[0169] This invention also provides a dual-mode carrier communication system, including a transmitter and a receiver, which are communicatively connected. When executed by a processor, this system implements the various processes of the above-described dual-mode carrier communication system HRF signal synchronization method embodiment and achieves the same technical effect. To avoid repetition, it will not be described again here.

[0170] This invention also provides a non-transitory computer-readable storage medium storing a computer program. When executed by a processor, the computer program implements the various processes of the above-described dual-mode carrier communication system HRF signal synchronization method embodiment and achieves the same technical effect. To avoid repetition, it will not be described again here.

[0171] The processor is the processor in the receiving end described in the above embodiments. The readable storage medium includes computer-readable storage media, such as computer read-only memory (ROM), random access memory (RAM), magnetic disk, or optical disk.

[0172] This invention also provides a computer program product, including a computer program that, when executed by a processor, implements the above-described HRF signal synchronization method for a dual-mode carrier communication system.

[0173] The processor is the processor in the receiving end described in the above embodiments. The readable storage medium includes computer-readable storage media, such as computer read-only memory (ROM), random access memory (RAM), magnetic disk, or optical disk.

[0174] This invention also provides a chip, which includes a processor and a communication interface. The communication interface is coupled to the processor. The processor is used to run programs or instructions to implement the various processes of the above-described dual-mode carrier communication system HRF signal synchronization method embodiment, and can achieve the same technical effect. To avoid repetition, it will not be described again here.

[0175] It should be understood that the chip mentioned in the embodiments of the present invention may also be referred to as a system-on-a-chip, system chip, chip system, or system-on-a-chip, etc.

[0176] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element. Furthermore, it should be noted that the scope of the methods and apparatuses in the embodiments of the present invention is not limited to performing functions in the order shown or discussed, but may also include performing functions substantially simultaneously or in the reverse order, depending on the functions involved. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.

[0177] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention, or the part that contributes to the related technology, can be embodied in the form of a computer software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of the present invention.

[0178] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other modifications under the guidance of the present invention without departing from the spirit and scope of the claims, and all of these modifications are within the protection scope of the present invention.

[0179] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0180] Unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form new technical solutions.

[0181] Unless otherwise specified, all technical features and optional technical features of this invention can be combined to form new technical solutions.

[0182] Unless otherwise specified, all steps of the present invention may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order; for example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0183] The above are merely preferred embodiments of the present invention and are not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for synchronizing HRF signals in a dual-mode carrier communication system, characterized in that, The method includes: Based on the maximum residual frequency offset range allowed by the HRF communication protocol, the frequency offset range is divided into several frequency offset assumption intervals, and each frequency offset assumption interval corresponds to a frequency offset assumption. The received signal is pre-compensated for frequency offset according to each frequency offset assumption interval to obtain multiple frequency offset compensation signals. The multi-channel frequency offset compensation signals are cross-correlated with the local reference sequence to obtain a multi-channel cross-correlation value sequence. In any cross-correlation value sequence, autocorrelation processing is performed on the cross-correlation values ​​of adjacent symbol intervals to obtain the autocorrelation values ​​based on adjacent symbol intervals under each frequency offset assumption; Based on multiple different adjacent symbol intervals, the corresponding autocorrelation values ​​are extracted to form a cross-interval autocorrelation value set; Multiple autocorrelation values ​​belonging to the same frequency offset hypothesis in the set of autocorrelation values ​​across the interval are incoherently superimposed to accumulate the amplitudes of multiple autocorrelation values ​​belonging to the same frequency offset hypothesis, so as to obtain the enhanced correlation peak value under each frequency offset hypothesis. Extract the enhanced correlation peaks corresponding to each frequency offset hypothesis, and determine the maximum correlation peak from them; If the maximum correlation peak value is greater than the synchronization determination threshold, the position corresponding to the maximum correlation peak value is determined as the synchronization position.

2. The method according to claim 1, characterized in that, The process of performing frequency offset pre-compensation on the received signal according to each frequency offset assumption interval to obtain multiple frequency offset compensated signals includes: The center frequency of each frequency offset assumption interval is determined, and the corresponding frequency offset compensation coefficient is generated based on the center frequency; Based on each frequency offset compensation coefficient, reverse phase rotation compensation is performed on the received signal to obtain a multi-channel frequency offset compensation signal corresponding to each frequency offset assumption.

3. The method according to claim 1 or 2, characterized in that, The step of performing cross-correlation processing on the multiple frequency offset compensation signals with the local reference sequence to obtain a multi-channel cross-correlation value sequence includes: For any frequency offset compensation signal, extract a sequence of sampling points with the same length as the local reference sequence within a sliding window; The cross-correlation value corresponding to the current window position is obtained by multiplying the sampled point sequence with the signal values ​​of the corresponding sampled points in the local reference sequence point by point in the complex field and summing the results. As the sliding window moves over the target frequency offset compensation signal, the above process is repeated to form a sequence of cross-correlation values ​​corresponding to the target frequency offset compensation signal.

4. The method according to claim 1, characterized in that, In any cross-correlation value sequence, autocorrelation processing is performed on the cross-correlation values ​​of adjacent symbol intervals to obtain the autocorrelation values ​​based on adjacent symbol intervals under each frequency offset assumption, including: For any cross-correlation value corresponding to any frequency offset compensation signal, the cross-correlation value of the current sampling point and the cross-correlation value with a preset symbol length interval between adjacent symbol intervals are selected to form a cross-correlation value pair for autocorrelation processing; By multiplying each pair of cross-correlation values ​​one by one, the autocorrelation value under the frequency offset assumption corresponding to the frequency offset compensation signal is obtained.

5. The method according to claim 1, characterized in that, The method of incoherently superimposing multiple autocorrelation values ​​belonging to the same frequency offset hypothesis in the set of autocorrelation values ​​across the interval, to accumulate the amplitudes of multiple autocorrelation values ​​belonging to the same frequency offset hypothesis, to obtain the enhanced correlation peak value under each frequency offset hypothesis, includes: For the correlation values ​​belonging to the same frequency offset hypothesis in the set of autocorrelation values ​​across the interval, the corresponding amplitude information is extracted to form an amplitude sequence; Based on the time position correspondence, the amplitude sequence is accumulated item by item at multiple adjacent symbol intervals to obtain the enhanced correlation peak under the corresponding frequency offset assumption.

6. The method according to claim 1, characterized in that, The frequency offset assumption interval is dynamically adjusted based on the signal characteristics of the received signal, which include at least the signal-to-noise ratio (SNR). Under high SNR conditions, the range of the frequency offset assumption interval is reduced, while under low SNR conditions, the range of the frequency offset assumption interval is expanded.

7. A dual-mode carrier communication system HRF signal synchronization device, characterized in that, The device includes: The partitioning module is used to divide the frequency offset range into several frequency offset assumption intervals based on the maximum residual frequency offset range allowed by the HRF communication protocol, with each frequency offset assumption interval corresponding to a frequency offset assumption. The pre-compensation module is used to perform frequency offset pre-compensation on the received signal according to each frequency offset assumption interval to obtain multiple frequency offset compensation signals; The cross-correlation module is used to perform cross-correlation processing on the multi-channel frequency offset compensation signals with the local reference sequence to obtain a multi-channel cross-correlation value sequence. The autocorrelation module is used to perform autocorrelation processing on the cross-correlation values ​​of adjacent symbol intervals in any cross-correlation value sequence to obtain the autocorrelation values ​​based on adjacent symbol intervals under each frequency offset hypothesis; based on multiple different adjacent symbol intervals, the corresponding autocorrelation values ​​are extracted to form a cross-interval autocorrelation value set; multiple autocorrelation values ​​belonging to the same frequency offset hypothesis in the cross-interval autocorrelation value set are incoherently superimposed to accumulate the amplitudes of multiple autocorrelation values ​​belonging to the same frequency offset hypothesis to obtain the enhanced correlation peak under each frequency offset hypothesis; The determination module is used to extract the enhanced correlation peaks corresponding to each frequency offset hypothesis, and to determine the maximum correlation peak. The determining module is further configured to determine the position corresponding to the maximum correlation peak as the synchronization position when the maximum correlation peak is greater than the synchronization determination threshold.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the HRF signal synchronization method for a dual-mode carrier communication system as described in any one of claims 1-6.

9. A dual-mode carrier communication system, characterized in that, include: The transmitter, used to send wireless signals; The receiving end is communicatively connected to the transmitting end and is used to receive wireless signals and execute the HRF signal synchronization method of the dual-mode carrier communication system as described in any one of claims 1-6.

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