Signal transmission and reception method

Abstract

The present disclosure proposes a signal transmitting and receiving method, which, in response to pre-acquiring a to-be-transmitted signal, divides the to-be-transmitted signal into multiple groups of to-be-processed data; for any to-be-processed data, generates a sub-composite waveform of the to-be-processed data according to each preset frequency in a preset frequency set; makes the transmitting signal simultaneously and in parallel transmit on sub-carriers in N mutually independent frequency sets, compensates for energy loss caused by fading; and according to a preset frame structure, combines the sub-composite waveform corresponding to each to-be-processed data with a preset preamble synchronization header and multiple pilot frames to obtain a target transmitting signal and transmit it. The high-sensitivity initial acquisition and coarse frequency offset estimation of a weak signal are realized; the multiple pilots enable the receiving end to maintain the orthogonality between carriers in the data demodulation process, avoids demodulation lock loss or energy leakage caused by frequency offset, and thus guarantees the stable connection of the link in a high-speed relative motion environment.

Description

Technical Field

[0001] This disclosure relates to the field of signal transceiver technology, specifically to a signal transmission and reception method. Background Technology

[0002] Long-distance communication refers to spatial communication involving complex physical environments and large spatial and temporal distances. On the one hand, long-distance communication requires traversing enormous physical distances, and the channels typically exhibit complex scattering and multipath effects, leading to severe path loss in the received signal and ultimately resulting in an extremely low signal-to-noise ratio. On the other hand, the high-speed relative motion between the transmitter and receiver introduces Doppler frequency shift during transmission, disrupting the orthogonality between signal carriers and causing severe inter-carrier interference. Therefore, there is an urgent need to propose a signal transmission method for long-distance communication. Summary of the Invention

[0003] This disclosure proposes a method for signal transmission and reception.

[0004] A first aspect of this disclosure provides a signal transmission method, the method comprising: In response to acquiring the signal to be transmitted, the signal to be transmitted is divided into multiple groups of data to be processed; For any data to be processed, a sub-composite waveform of the data to be processed is generated according to each preset frequency in the preset frequency set; wherein, the preset frequency set includes N mutually independent frequency sets; any set of frequency sets includes M orthogonal subcarriers, and the center frequency interval of different frequency sets is greater than the channel coherence bandwidth; N and M are integers greater than or equal to 2; According to the preset frame structure, the sub-composite waveforms corresponding to each data to be processed are combined with the preset preamble synchronization head and multiple guide frames to obtain the target transmission signal and transmit it.

[0005] In this embodiment of the disclosure, dividing the signal to be transmitted into multiple groups of data to be processed includes: The number of bits included in any set of data to be processed is calculated based on a preset modulation order; wherein the modulation order represents the amount of information carried by any set of data to be processed; and the preset modulation order is the number of orthogonal subcarriers in any set of frequencies. Starting from the beginning of the signal to be transmitted, each consecutive number of bits is divided into a group of data to be processed.

[0006] In this embodiment of the disclosure, generating a sub-composite waveform of the data to be processed based on each preset frequency in a preset frequency set includes: Convert the data to be processed into a filtering index; For any set of frequencies, select the target orthogonal subcarriers corresponding to the selection index; The sub-composite waveform is obtained by superimposing the target orthogonal subcarriers corresponding to all frequency sets.

[0007] In this embodiment of the disclosure, converting the data to be processed into a filtering index includes: Transform the data to be processed into data to be mapped; The index of the data to be mapped is determined according to the preset mapping rules.

[0008] In this embodiment of the disclosure, the preset frame structure includes a preamble, multiple data symbols, and multiple pilot frames; the multiple pilot symbols and the multiple data symbols are time-division interleaved; each data symbol is used to transmit a corresponding sub-composite waveform; The duration of the preamble synchronization head is greater than or equal to N times the duration of the data symbol, where N is an integer greater than or equal to 2; The duration of the pilot frame is greater than or equal to the maximum multipath delay spread of the channel through which the target transmitted signal is transmitted.

[0009] A second aspect of this disclosure provides a signal receiving method, the method comprising: In response to acquiring the signal to be received, the target start frame of the signal to be received is determined; Based on the target start frame and the pre-acquired frame structure, the signal to be received is initially frequency corrected to obtain the initial received signal; Phase compensation is performed on the initial received signal based on the pre-acquired frame structure; Based on the pre-acquired frequency set parameters, the initial received signal after phase compensation is demodulated to obtain the target received signal; the frequency set parameters include N mutually independent frequency sets; any set of frequencies includes M orthogonal subcarriers; N and M are integers greater than or equal to 2.

[0010] In this embodiment of the disclosure, determining the target start frame of the signal to be received includes: In response to the ratio of the spectral peak to the noise floor of the acquired signal being received being greater than a preset ratio threshold, the starting frame of the signal being received is taken as the initial starting frame. Starting from the initial start frame, sampling is performed within the preamble duration, and the cross-correlation characteristics of each sampling point are calculated; where the preamble duration refers to the duration of the preamble synchronization header in the pre-acquired frame structure; The point with the largest cross-correlation feature is taken as the target starting frame of the signal to be received.

[0011] In this embodiment of the disclosure, the step of performing preliminary frequency correction on the signal to be received based on the target start frame and the pre-acquired frame structure to obtain an initial received signal includes: Starting from the target start frame, obtain the measurement frequency of the preamble synchronization head during the preamble duration; Calculate the frequency offset between the pre-acquired reference frequency of the preamble sync head and the measured frequency; Based on the frequency offset, the signal to be received is initially frequency corrected to obtain the initial received signal.

[0012] In this embodiment of the disclosure, the step of performing phase compensation on the initial received signal according to the pre-acquired frame structure includes: Obtain the measured pilot frame frequency of each pilot frame in the initial received signal; For any pilot frame, calculate the frequency offset correction between the measured pilot frame frequency and the reference pilot frame frequency; The phase of the data symbol corresponding to the pilot frame is rotated according to the frequency offset correction amount to complete the phase compensation of the initial received signal.

[0013] In this embodiment of the disclosure, the step of performing phase rotation on the data symbols corresponding to the pilot frame according to the frequency offset correction amount includes: Phase rotation is performed on the data symbols in the frame following the preamble frame; wherein, the phase rotation of the data symbols in the first frame is performed according to the frequency offset of the preamble sync head.

[0014] In this embodiment of the disclosure, the step of demodulating the initial received signal after phase compensation according to the pre-acquired frequency set parameters to obtain the target received signal includes: The initial received signal after phase compensation is converted into a frequency domain received signal; Based on the pre-acquired frequency mapping rules, the target orthogonal subcarrier corresponding to any data symbol in the frequency domain received signal is determined; The target received signal is obtained by inverse mapping based on the target orthogonal subcarriers.

[0015] In this embodiment of the disclosure, determining the target orthogonal subcarrier corresponding to any data symbol in the frequency domain received signal according to a pre-acquired frequency mapping rule includes: For any data symbol, traverse the M candidate symbol indices; the M candidate symbol indices are determined according to the frequency mapping rules preset by the transmitter. For any candidate symbol index, determine its N diversity frequency points in the N frequency sets according to the frequency mapping rule; On the frequency domain received signal, find the frequency positions corresponding to the N diversity frequency points respectively; Extract the corresponding signal energy based on each of the aforementioned frequency positions; The signal energy corresponding to each frequency position is extracted and accumulated to obtain the total energy corresponding to the preset orthogonal subcarrier; Compare the total energy corresponding to each symbol, and take the symbol with the largest total energy as the target orthogonal subcarrier.

[0016] An embodiment of the third aspect of this disclosure provides an electronic device including a memory, a processor, and a computer program stored in the memory and executable on the processor, the processor running the computer program to implement the methods described in the first aspect and any optional real-time mode of the first aspect, or the second aspect and any optional real-time mode of the second aspect.

[0017] An embodiment of the fourth aspect of this disclosure provides a computer-readable storage medium having a computer program stored thereon, the program being executed by a processor to implement the method described in the first aspect and any optional real-time mode of the first aspect, or the method described in the second aspect and any optional real-time mode of the second aspect.

[0018] The technical solutions provided in this disclosure have at least the following technical effects or advantages: In response to the pre-acquired signal to be transmitted, the signal to be transmitted is divided into multiple groups of data to be processed. For any data to be processed, a sub-composite waveform of the data to be processed is generated according to each preset frequency in a preset frequency set. The preset frequency set includes N independent frequency sets; each frequency set includes M orthogonal subcarriers; N and M are integers greater than or equal to 2. This allows the transmitted signal to be transmitted in parallel on the subcarriers in the N independent frequency sets, so that the receiver can non-coherently combine the energy of these N frequency points. When some frequency points fall into the deep fading point of the channel due to multipath effects, other unfaded frequency points can still provide sufficient signal energy to compensate for the energy loss caused by fading. According to the preset frame structure, the sub-composite waveforms corresponding to each data to be processed are combined with a preset preamble synchronization header and multiple pilot frames to obtain the target transmitted signal and transmit it. The pre-set preamble synchronization head provides sufficient processing gain for the receiver under extremely low signal-to-noise ratio conditions, enabling high-sensitivity initial acquisition and coarse frequency offset estimation of weak signals; the interleaved pilots act as dynamic frequency beacons, enabling the receiver to continuously and in real time track and correct rapidly changing residual Doppler frequency offsets during data demodulation, maintaining the orthogonality between carriers, avoiding demodulation loss of lock or energy leakage due to frequency offset, and thus ensuring stable link connection in high-speed relative motion environments.

[0019] Additional aspects and advantages of this disclosure 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 this disclosure. Attached Figure Description

[0020] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this disclosure. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 A schematic flowchart of a signal transmission method provided in an embodiment of this disclosure is shown; Figure 2 A schematic diagram of symbol indexing in a signal transmission method provided in an embodiment of this disclosure is shown; Figure 3A and Figure 3B This diagram illustrates a frame structure in a signal transmission method provided by an embodiment of the present disclosure; Figure 4 A schematic flowchart of a signal receiving method provided in an embodiment of this disclosure is shown; Figure 5 A schematic diagram of signal transmission and signal reception provided in an embodiment of this disclosure is shown; Figure 6 A schematic diagram of the structure of an electronic device provided in an embodiment of the present disclosure is shown; Figure 7 A schematic diagram of a storage medium provided according to an embodiment of the present disclosure is shown. Detailed Implementation

[0021] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0022] It should be noted that, unless otherwise stated, the technical or scientific terms used in this disclosure shall have the ordinary meaning as understood by one of ordinary skill in the art to which this disclosure pertains.

[0023] The following describes the technical scenarios involved in the embodiments of this disclosure.

[0024] In long-distance Earth-Moon-Earth (EME) space communication, signal transmission faces extreme physical challenges. First, the enormous path loss caused by the ultra-long distance means the received signal is often deeply buried beneath a noisy substrate, resulting in an extremely low signal-to-noise ratio at the receiver. Second, the high-speed relative motion between communication nodes introduces severe Doppler shifts of up to tens of kHz, while multipath effects arise from the rough surfaces of distributed reflectors. These factors combine to create a challenging composite channel characterized by weak signals, high dynamics, and deep fading.

[0025] To address these challenges, coherent spread spectrum and coding techniques (such as DSSS or low-rate BPSK), while performing excellently in GPS and deep space telemetry and control by trading high coding gain for a higher signal-to-noise ratio, heavily rely on the receiver's phase-locked loop (PLL) for precise carrier phase tracking. Under the aforementioned channel conditions, the PLL is highly susceptible to loss of lock, leading to link interruption. As an alternative, dedicated digital modes for weak signals (such as JT65 / FT8) have been developed for civilian applications. While these protocols excel in weak signal detection, they are typically designed for quasi-static or low-speed scenarios, rely on precise global time synchronization, and have extremely low communication rates, making them ill-suited for the drastic Doppler shifts and real-time requirements of non-cooperative reflection communication.

[0026] In view of the above, this disclosure proposes a signal transmission method. In this disclosure, the signal transmission method proposed according to the present disclosure is described below with reference to examples.

[0027] Figure 1 This disclosure illustrates a signal transmission method according to an embodiment of the present disclosure, applicable to scenarios such as long-distance space communication, Earth-Moon space communication, and low-Earth orbit satellite links. The signal transmission method of this embodiment may include the following steps: In step S11, in response to acquiring the signal to be transmitted, the signal to be transmitted is divided into multiple groups of data to be processed; For example, after receiving the raw binary bit stream to be sent (i.e., the signal to be transmitted), the first step is to divide the continuous bit stream into several data blocks according to predetermined rules. Each data block is called a group of data to be processed. There are various ways to implement the specific division rules, each suited to different system design goals. Fixed-length grouping: The number of bits in any group of data to be processed is calculated based on a preset modulation order; where the modulation order represents the amount of information carried by any group of data to be processed; the preset modulation order is the number of orthogonal subcarriers in any set of frequencies; starting from the beginning of the signal to be transmitted, bits of every consecutive number of bits are divided into a group of data to be processed. For example, based on the modulation order M, the number of bits in each group is determined as k = log₂M. Bits are then sequentially extracted from the beginning of the bit stream according to this fixed length k. The advantages are its simplicity, logical regularity, and ease of use for frame structure and demodulation processing at the receiving end, making it the most commonly used and reliable method in digital modulation.

[0028] Adaptive length packetization: The packet length can be dynamically adjusted based on channel conditions, service type, or priority. For example, a larger M (i.e., more bits per packet) can be used when the channel quality is good to improve spectral efficiency; a smaller M can be used when the channel is poor to enhance reliability. The advantage lies in its ability to flexibly balance system transmission efficiency and communication robustness, improving the system's adaptability to time-varying channels.

[0029] Those skilled in the art can flexibly set the specific rules for grouping, the bit length of each data group, and the number of groups based on the specific communication protocol, modulation method, and trade-off between transmission efficiency and reliability; this invention does not impose any limitations on these. For example, Cyclic Redundancy Check (CRC) or other padding bits required for encoding can be considered when grouping.

[0030] In step S12, for any data to be processed, a sub-composite waveform of the data to be processed is generated according to each preset frequency in the preset frequency set.

[0031] The preset frequency set includes N independent frequency sets; each frequency set includes M orthogonal subcarriers, and the center frequency interval of different frequency sets is greater than the channel coherence bandwidth; N and M are integers greater than or equal to 2.

[0032] For example, in long-distance reflection channels, conventional single-frequency modulation (such as single-tone MFSK) concentrates signal energy on a single frequency. When this frequency encounters "deep fading" caused by complex multipath effects, the signal energy is severely attenuated or even canceled out, leading to incorrect demodulation at the receiver and forming an unavoidable error plane, severely limiting the reliability of the communication link. This step solves the problem of weak resistance to frequency-selective fading by introducing an "N-fold frequency diversity" modulation mechanism. Utilizing the channel's uncorrelation in the frequency domain, the energy of the same set of information (data to be processed) is simultaneously distributed across N independent frequency channels for transmission. Thus, even if some frequency points encounter deep fading, the other unfaded frequency points can still carry sufficient information energy, thereby achieving "diversity gain" at the receiver through energy combining, effectively combating deep fading.

[0033] For the current set of data to be processed, a specific set of frequencies corresponding to it is determined from the preset frequency set, and then a composite waveform signal is generated based on these frequencies. This waveform is called the sub-composite waveform of the data set.

[0034] The preset frequency set can be N independent frequency sets, each containing M orthogonal subcarriers. For example, set 1: {f1_0, f1_1, f1_2, f1_3} has 4 orthogonal subcarriers. Set 2: {f2_0, f2_1, f2_2, f2_3} also has 4 orthogonal subcarriers, and the frequency spacing between these subcarriers and those in set 1 is sufficiently large (greater than the coherence bandwidth). In this case, N equals 2 and M equals 4. Corresponding frequencies are selected from sets 1 and 2, and a sub-composite waveform is generated based on the two selected frequencies.

[0035] In some embodiments, during the implementation of step S12 above, how to determine the corresponding target frequency (target orthogonal subcarrier) in each frequency set and finally synthesize the physical waveform carrying the information is crucial. The lack of such a mechanism would lead to chaotic frequency mapping, preventing the receiver from demodulating correctly. This embodiment ensures that the transmitter can replicate and send the same information on N independent frequency channels according to unified rules, laying a solid foundation for the receiver to perform reliable incoherent energy combining detection based on known mapping rules. This provides a concrete operational guarantee for realizing N-fold frequency diversity modulation. For example, the data to be processed is converted into a filtering index; for any frequency set, the target orthogonal subcarriers corresponding to the filtering index are filtered; the target orthogonal subcarriers corresponding to all frequency sets are superimposed to obtain the sub-composite waveform.

[0036] For example, the filtering index is an integer value or identifier obtained by mapping the data to be processed according to certain rules. It acts as a key connecting the information content and physical frequency resources. This index can be a decimal value after mapping from natural binary or a value after Gray encoding. The purpose is to ensure that the bit groups corresponding to adjacent indices differ by only one bit, thereby reducing the number of bit errors when a decision is made incorrectly. For example, the data to be processed is converted into data to be mapped; the index of the data to be mapped is determined according to a preset mapping rule. The target orthogonal subcarrier refers to the subcarrier uniquely determined from M candidate orthogonal subcarriers in a specific set of frequencies, based on the value obtained from the filtering index. For example, assuming that the Gray mapping index corresponding to the data symbol is 1, then in both set 1 and set 2, frequencies with index 1 are selected, namely f1_1 and f2_1. Figure 2 As shown, this is a method for selecting orthogonal subcarriers with symbol index k from N frequency sets.

[0037] In signal processing, superposition refers to the operation of adding the amplitude values ​​of two or more time-domain waveforms (signals) at the same time to form a new composite waveform. Here, it involves synthesizing sine waves or modulated waveforms at different center frequencies.

[0038] In the implementation, the binary bit groups of the data to be processed are directly interpreted as corresponding decimal integers. For example, the bit group "10" is converted to the decimal index 2. The advantage lies in the extremely simple mapping and inverse mapping logic and minimal computational overhead. Gray mapping first converts the binary bit groups into natural binary indices, and then converts them into Gray code indices using Gray encoding rules.

[0039] Those skilled in the art can select different index mapping rules, frequency selection mechanisms, and waveform synthesis methods based on the specific system architecture, processing capabilities, and flexibility requirements. The generation of the filtering index is not limited to the two mapping methods mentioned above and may also include other forms of channel coding or symbol mapping. The determination of the target orthogonal subcarriers can also be a combination of table lookup and calculation methods. The specific implementation of waveform superposition can also employ different analog or digital technical paths, and this invention does not impose any limitations on this.

[0040] In step S13, according to the preset frame structure, the sub-composite waveforms corresponding to each data to be processed are combined with the preset preamble synchronization head and multiple guide frames to obtain the target transmission signal and transmit it.

[0041] For example, a complete physical layer transmission unit is constructed by structurally combining sub-composite waveforms and auxiliary control information (preamble, pilot) in the time domain through a preset frame structure. Its combined effects are: 1) Reliable signal acquisition and coarse synchronization are achieved under extremely low signal-to-noise ratio conditions using a preset preamble; 2) Real-time tracking and compensation for high dynamic Doppler frequency shift are achieved using multiple interleaved pilots, while simultaneously serving as a time-domain guard interval to suppress inter-symbol interference.

[0042] After obtaining the sub-composite waveforms corresponding to each set of data to be processed, according to the preset frame structure, each sub-composite waveform is spliced ​​with the signal segment of the preset leader and the signal segments of multiple pilots. The splicing is done in the order of the frame structure to form a complete and structured signal sequence. This final signal sequence is the target transmission signal.

[0043] In some embodiments, such as Figure 3A The preset frame structure includes one preamble, multiple data symbols, and multiple pilot frames; the multiple pilot symbols and the multiple data symbols are time-division interleaved; any data symbol is used to transmit the corresponding sub-composite waveform; the duration of the preamble is greater than or equal to N times the duration of the data symbol, where N is an integer greater than or equal to 2; the duration of the pilot frame is greater than or equal to the maximum multipath delay spread of the channel transmitting the target signal.

[0044] The duration of the preamble sync header; The duration of the data symbol; The duration of the guide frame.

[0045] The preamble is a specific signal segment located at the very beginning of the frame structure. It is typically a known signal with simple yet unique characteristics, such as a long-duration single tone or a specific pseudo-random code sequence. Its main function is to assist the receiver in signal detection, frame start positioning, and coarse frequency estimation. The pilot is a known signal segment periodically inserted between data symbols in the frame structure. The pilot is also usually a single-tone signal, serving two purposes: first, as a frequency reference for the receiver to estimate and track time-varying frequency offsets and phase noise introduced by the channel; and second, due to its specific duration design, it can also act as a guard interval to absorb multipath trailing from the preceding data symbol, thereby suppressing inter-symbol interference. Figure 3B As shown, the maximum multipath delay spread is obtained through channel measurements. Next, the duration of the pilot signal... Set to be greater than or equal to this maximum delay value (i.e.) This can completely accommodate the hysteresis tail component generated by the previous data symbol in the multipath channel. If the fading corresponding to the maximum delay is very high, the delay tail of this path can also be ignored. The delay is set to be greater than or equal to the previous level. When generating the transmit signal by splicing according to the preset frame structure, a phase accumulator can be set up to calculate the instantaneous phase value at the end of the previous data symbol in real time when generating the waveform of k symbols. Subsequently, this phase value is directly assigned as the starting phase of the (k+1)th symbol to ensure phase continuity between adjacent data symbols.

[0046] As can be seen, by implementing the above signal transmission method, in response to the pre-acquired signal to be transmitted, the signal to be transmitted is divided into multiple groups of data to be processed; for any data to be processed, a sub-composite waveform of the data to be processed is generated according to each preset frequency in the preset frequency set; wherein, the preset frequency set includes N mutually independent frequency sets; any frequency set includes M orthogonal subcarriers; N and M are integers greater than or equal to 2; so that the transmitted signal is transmitted in parallel on the subcarriers in the N mutually independent frequency sets, and the receiver can non-coherently combine the energy of these N frequency points. When some frequency points fall into the deep fading point of the channel due to multipath effect, other non-fading frequency points can still provide sufficient signal energy, thereby compensating for the energy loss caused by fading; according to the preset frame structure, the sub-composite waveforms corresponding to each data to be processed are combined with the preset preamble synchronization header and multiple pilot frames to obtain the target transmitted signal and transmit it. The pre-set preamble synchronization head provides sufficient processing gain for the receiver under extremely low signal-to-noise ratio conditions, enabling high-sensitivity initial acquisition and coarse frequency offset estimation of weak signals; the interleaved pilots act as dynamic frequency beacons, enabling the receiver to continuously and in real time track and correct rapidly changing residual Doppler frequency offsets during data demodulation, maintaining the orthogonality between carriers, avoiding demodulation loss of lock or energy leakage due to frequency offset, and thus ensuring stable link connection in high-speed relative motion environments.

[0047] Corresponding to the above implementation of the signal transmission method, this disclosure also provides a signal reception method, such as... Figure 4 As shown, the signal receiving method includes: In step S41, in response to acquiring the signal to be received, the target start frame of the signal to be received is determined; For example, after receiving a radio frequency signal from the channel and undergoing preliminary processing (such as frequency conversion and sampling) to obtain a baseband digital signal sequence, this sequence is called the signal to be received. This signal to be received needs to be processed to determine the start position of a complete transmission frame; the start time is the target starting frame. This achieves initial detection and frame synchronization of the input signal stream, providing a relatively accurate timing reference for subsequent time synchronization, frequency offset estimation, and frame data extraction.

[0048] In some embodiments, determining the target start frame of the signal to be received includes: in response to the ratio of the spectral peak to the noise floor of the acquired signal to be received being greater than a preset ratio threshold, taking the start frame of the signal to be received as the initial start frame; starting from the initial start frame, sampling is performed within the preamble duration, and the cross-correlation characteristics of each sampling point are calculated; wherein the preamble duration refers to the duration of the preamble synchronization header in the pre-acquired frame structure; and the point with the largest cross-correlation characteristic is taken as the target start frame of the signal to be received.

[0049] For example, when the ratio of the spectral peak energy to the noise floor energy of the received signal exceeds a preset ratio threshold, it is determined that the signal has been captured, and the start position of the signal frame at this moment is roughly recorded as the initial start frame. Starting from the rough position marked by the initial start frame, a segment of the signal with a length equal to the preamble duration is extracted; the value of the preamble duration can be obtained in advance. Then, on this segmented signal, its cross-correlation characteristics with the locally stored, known preamble sequence at each sampling point are calculated. Finally, the receiver finds the point with the largest value among all the calculated cross-correlation characteristic values ​​and determines the time corresponding to this point as the precise start position of the signal to be received, i.e., the target start frame. Based on these two progressive operations of "coarse capture based on the spectral noise ratio threshold to determine the initial start frame" and "search based on the preamble cross-correlation peak to determine the target start frame," a two-stage frame synchronization mechanism that balances high detection sensitivity and high timing accuracy is implemented.

[0050] In step S42, based on the target starting frame and the pre-acquired frame structure, preliminary frequency correction is performed on the signal to be received to obtain the initial received signal.

[0051] For example, the frame structure specifies the position and length of the preamble synchronization header within the frame. After determining the target start frame, a signal segment corresponding to the preamble synchronization header is extracted from the signal to be received, based on the pre-acquired frame structure. The frequency offset carried by the signal is estimated based on the preamble signal segment. Based on the estimated frequency offset value, frequency compensation is performed on the signal to be received starting from the target start frame to eliminate or reduce the frequency offset.

[0052] In some embodiments, preliminary frequency correction can be achieved by: starting from the target start frame, acquiring the measurement frequency of the preamble sync head during the preamble duration; calculating the frequency offset between the pre-acquired reference frequency and the measurement frequency of the preamble sync head; and performing preliminary frequency correction on the signal to be received based on the frequency offset to obtain the initial received signal.

[0053] For example, the reference frequency refers to the nominal carrier frequency that is predetermined when the transmitter generates the preamble synchronization head, which is usually zero frequency (0Hz).

[0054] An FFT is performed on the extracted preamble signal segment, and the spectral line with the largest amplitude is searched in the spectrum; the frequency corresponding to this spectral line is the measurement frequency. The frequency can also be estimated by calculating the rate of change of the signal phase over time. Based on the calculated frequency offset, a complex exponential sequence is generated in the digital domain. This complex exponential sequence is then multiplied by the signal to be received, sample by sample. In a receiver using a digitally controlled oscillator for down-conversion, the estimated frequency offset is fed back to the digitally controlled oscillator as a correction value, adjusting its output frequency, thus completing the correction at the mixer stage. This allows for tight integration with the receiver front-end architecture, achieving low-latency correction.

[0055] Those skilled in the art can select the measurement frequency and the specific algorithm for frequency correction based on the requirements for frequency offset estimation accuracy and speed in the design of the preamble signal, as well as the hardware processing capabilities. Preliminary frequency correction can be applied to the entire frame buffer or applied in real-time to subsequent data streams; this invention does not limit this application.

[0056] In step S43, phase compensation is performed on the initial received signal according to the pre-acquired frame structure.

[0057] For example, after the initial frequency correction is completed, although the main part of the signal spectrum is moved back to the vicinity of the baseband zero frequency, in high dynamic communication scenarios, due to the relative acceleration between the transmitting and receiving nodes or the time-varying characteristics of the channel, the carrier frequency and phase of the signal will still change rapidly over time, which will destroy the phase continuity within and between data symbols.

[0058] Using known pilot symbols, the error of the signal phase change over time is estimated. Then, based on the estimation results, the phase of the data symbols located between the pilots in the initial received signal is adjusted to eliminate or reduce the phase error.

[0059] In some embodiments, phase compensation is performed on the initial received signal according to the pre-acquired frame structure, including: acquiring the measured guide frame frequency of each guide frame in the initial received signal; for any guide frame, calculating the frequency offset correction amount between the measured guide frame frequency and the reference guide frame frequency; and performing phase rotation on the data symbols corresponding to the guide frame according to the frequency offset correction amount to complete the phase compensation of the initial received signal.

[0060] For example, based on the timing of the frame structure, signal segments corresponding to each pilot symbol are extracted from the initial received signal. For each extracted pilot signal segment, the phase or frequency deviation of each pilot signal relative to the local nominal pilot (zero frequency) is analyzed. For example, the residual frequency offset at that moment can be estimated by calculating the average phase offset of the pilot segment or by measuring its instantaneous frequency (e.g., through phase difference). Phase / frequency error estimates discretely distributed over time are obtained.

[0061] Using this discrete error estimate, a phase compensation function is constructed through interpolation or filtering. This function describes how the phase error changes from the previous pilot to the next pilot.

[0062] Based on the constructed compensation function, a corresponding complex compensation sequence is generated. This complex compensation sequence is then multiplied by the data symbols (i.e., the signals between pilots) in the corresponding time period of the initial received signal, either by sample point or by symbol, thereby completing dynamic phase compensation.

[0063] In the specific implementation of phase compensation, it is necessary to clearly define which data symbols the frequency offset correction amount for each pilot applies to. If the correspondence is not clear, it may lead to omissions (some symbols are not compensated) or overlaps (some symbols are repeatedly compensated) in phase compensation, thereby introducing new phase jumps and destroying the compensation effect. In some embodiments, phase rotation is performed on the data symbols corresponding to the pilot frame according to the frequency offset correction amount, including: phase rotation of the data symbols located in the frame following the pilot frame; wherein, the data symbols of the first frame are phase rotated according to the frequency offset of the preamble sync head.

[0064] For example, a frame refers to a basic unit in the frame structure, such as a data symbol slot. Therefore, the data symbol of the frame following the pilot frame refers to the data symbol slot that appears immediately after the pilot symbol in time sequence; this is the target of the pilot frequency offset estimation. The first frame data symbol refers to the first data symbol carrying user information that appears after the preamble, marking the beginning of the data segment. The preamble frequency offset refers to the frequency deviation between the measured frequency and the reference frequency at the preamble.

[0065] In step S44, the initial received signal after phase compensation is demodulated according to the pre-acquired frequency set parameters to obtain the target received signal; the frequency set parameters include N independent frequency sets; any set of frequencies includes M orthogonal subcarriers; N and M are integers greater than or equal to 2.

[0066] For example, the receiving end performs demodulation on the initial received signal that has undergone phase compensation processing, based on the frequency set parameters of the transmitter's frequency resource planning that were pre-acquired and stored before communication. The purpose of demodulation is to extract the information carried by the corrected signal, and the resulting binary bit stream is the target received signal.

[0067] In some embodiments, the target received signal is obtained by demodulating the initial received signal after phase compensation according to the pre-acquired frequency set parameters, including: converting the initial received signal after phase compensation into a frequency domain received signal; determining the target orthogonal subcarrier corresponding to any data symbol in the frequency domain received signal according to the pre-acquired frequency mapping rules; and performing inverse mapping based on the target orthogonal subcarrier to obtain the target received signal.

[0068] For example, the initial received signal (time-domain waveform) that has undergone phase compensation processing is converted into a frequency-domain received signal using a fast Fourier transform. The frequency-domain received signal characterizes the amplitude and phase (or energy) distribution of the original signal at different frequency components.

[0069] For any data symbol in the entire frame represented by the frequency-domain received signal, the receiver determines a specific set of frequency components in the frequency domain representation corresponding to that data symbol, based on a frequency mapping rule pre-acquired and consistent with that of the transmitter. These frequency components are the "target orthogonal subcarriers" selected during the transmission of that data symbol. Based on the characteristics exhibited by the determined target orthogonal subcarriers in the frequency-domain received signal, inverse mapping is performed. Through the inverse mapping process, the original information units (symbols or bit groups) represented by the data symbol are recovered from the frequency characteristics. The information units of all data symbols are then combined sequentially to obtain the target received signal.

[0070] In some embodiments, determining the target orthogonal subcarrier corresponding to any data symbol in the frequency domain received signal according to a pre-acquired frequency mapping rule includes: for any data symbol, traversing M candidate symbol indices; the M candidate symbol indices are determined according to a frequency mapping rule preset by the transmitter; for any candidate symbol index, determining the N diversity frequency points corresponding to it in N frequency sets according to the frequency mapping rule; finding the frequency positions corresponding to the N diversity frequency points in the frequency domain received signal; extracting the corresponding signal energy based on each frequency position; accumulating the signal energy extracted from each frequency position to obtain the total energy corresponding to the preset orthogonal subcarrier; comparing the total energy corresponding to each symbol, and taking the symbol with the largest total energy as the target orthogonal subcarrier.

[0071] For example, consider all M possible symbols to be transmitted (symbol 0, symbol 1, …, symbol M-1). For a symbol hypothesis currently being tested (denoted as symbol h), based on the "pre-acquired frequency mapping rules," determine the N specific, independent frequency components corresponding to symbol h at the time of transmission. These N frequency components are the "N diversity frequencies" of symbol h, each located in a different set of frequencies. In the current "frequency domain received signal" (i.e., the spectrum of the data symbol), find the frequency positions corresponding to the aforementioned N diversity frequencies. Extract the signal energy values ​​at these N positions from the spectrum. Sum the extracted N energy values ​​to obtain the total energy. This total energy represents "the total energy that can be received at all N diversity frequencies if the transmitted symbol is h," and is called the "combined decision statistic" or "total energy" of symbol h. Perform the above steps for each of the M possible symbol hypotheses to obtain M "total energy" values. Compare these M total energy values, and assume that the symbol with the largest total energy value is the actual symbol transmitted in the current data symbol. The frequency set (N diversity frequency points) corresponding to this determined symbol is the frequency "activated" within the current symbol period.

[0072] As can be seen, by implementing the above signal receiving method, in response to acquiring the signal to be received, the target starting frame of the signal to be received is determined; based on the target starting frame and the pre-acquired frame structure, preliminary frequency correction is performed on the signal to be received to obtain the initial received signal; based on the pre-acquired frame structure, phase compensation is performed on the initial received signal; based on the pre-acquired frequency set parameters, the phase-compensated initial received signal is demodulated to obtain the target received signal; the frequency set parameters include N mutually independent frequency sets; any frequency set includes M orthogonal subcarriers; N and M are integers greater than or equal to 2. This method enables signal detection and determination of the target starting frame under low signal-to-noise ratio conditions, providing a time reference. Through preliminary frequency correction and phase compensation, the phase continuity of the signal is maintained throughout the entire frame duration, preventing spectral leakage and orthogonality destruction.

[0073] like Figure 5 The diagram shows the above signal transmission and reception methods. The transmitter first receives the input bits, which are then processed by serial-to-parallel conversion, Gray mapping, frame assembly, and pilot insertion. The processed bits then enter the multi-band diversity modulation module. This module generates N sets of transmission signal frames, namely “transmission (1) band generation (f1)”, “transmission (2) band generation (f2)”, and so on, “transmission n band generation (fn)” (each set corresponds to a frequency set containing M orthogonal subcarriers). These signal frames are summed and merged, then up-converted into radio frequency signals by the radio frequency module, and finally transmitted to the wireless channel by the transmitting antenna.

[0074] The receiver captures the signal transmitted through the wireless channel (including noise) via the receiving antenna. After down-conversion to baseband signal by the RF module, analog-to-digital conversion is performed by the ADC. Then, coarse acquisition is performed based on the preamble synchronization header, and synchronization is performed again based on the pilot frame frequency offset. Frequency offset and timing deviation are compensated by data symbol estimation (frequency offset and symbol synchronization). After that, the time domain signal is converted to the frequency domain by FFT, and energy is extracted and combined from the N diversity frequency points of each data symbol by combining multi-band diversity demodulation. Finally, the final bit stream is output through maximum likelihood detection and Gray inverse mapping.

[0075] This disclosure also provides an electronic device for performing the above-described signal transmission method. Please refer to... Figure 6 This illustrates a schematic diagram of an electronic device provided by some embodiments of the present disclosure. For example... Figure 6 As shown, the electronic device includes: a processor 600, a memory 601, a bus 602, and a communication interface 603. The processor 600, the communication interface 603, and the memory 601 are connected via the bus 602. The memory 601 stores a computer program that can run on the processor 600. When the processor 600 runs the computer program, it executes the aforementioned provisions of this disclosure. Figure 1 or Figure 4 The method provided by any of the illustrated embodiments.

[0076] The memory 601 may include high-speed random access memory (RAM) or non-volatile memory, such as at least one disk storage device. Communication between this system network element and at least one other network element is achieved through at least one communication interface 603 (which can be wired or wireless), such as the Internet, wide area network, local area network, or metropolitan area network.

[0077] Bus 602 can be an ISA bus, PCI bus, or EISA bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. Memory 601 is used to store programs, and the processor 600 executes the programs after receiving execution instructions. Figure 1 or Figure 4 The illustrated method can be applied to or implemented by the processor 600.

[0078] The processor 600 may be an integrated circuit chip with signal processing capabilities. In implementation, each step of the above method can be completed by the integrated logic circuitry in the hardware of the processor 600 or by instructions in software form. The processor 600 may be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it may also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), an off-the-shelf programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this disclosure. The general-purpose processor may be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this disclosure can be directly embodied in the execution of a hardware decoding processor, or executed by a combination of hardware and software modules in the decoding processor. The software modules may reside in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. The storage medium is located in memory 601. Processor 600 reads the information in memory 601 and, in conjunction with its hardware, completes the steps of the above method.

[0079] The electronic device and the signal transmission method provided in this disclosure are based on the same inventive concept and have the same beneficial effects as the methods they employ, operate, or implement.

[0080] This disclosure also provides a computer-readable storage medium corresponding to the signal transmission method provided in the foregoing embodiments. Please refer to... Figure 7 The computer-readable storage medium shown is an optical disc 30, on which a computer program (i.e., a program product) is stored. When the computer program is run by a processor, it executes the signal transmission method provided in any of the foregoing embodiments.

[0081] It should be noted that examples of the computer-readable storage medium may also include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other optical and magnetic storage media, which will not be elaborated here.

[0082] The computer-readable storage medium provided in the above embodiments of this disclosure and the signal transmission method provided in the embodiments of this disclosure are based on the same inventive concept and have the same beneficial effects as the methods adopted, run or implemented by the applications stored therein.

[0083] It should be noted that: Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of this disclosure may be practiced without these specific details. In some instances, well-known structures and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0084] Similarly, it should be understood that, in order to simplify this disclosure and aid in understanding one or more of the various inventive aspects, in the above description of exemplary embodiments of this disclosure, various features of this disclosure are sometimes grouped together in a single embodiment, figure, or description thereof. However, this approach to disclosure should not be construed as reflecting a schematic diagram in which the claimed disclosure requires more features than are expressly recited in each claim. Rather, as reflected in the following claims, inventive aspects lie in fewer than all features of a single foregoing disclosed embodiment. Therefore, the claims following the detailed description are hereby expressly incorporated into that detailed description, wherein each claim itself is a separate embodiment of this disclosure.

[0085] Furthermore, those skilled in the art will understand that although some embodiments described herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of this disclosure and form different embodiments. For example, in the following claims, any of the claimed embodiments can be used in any combination.

[0086] The above description is merely a preferred embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. A signal transmission method, characterized in that, The method includes: In response to acquiring the signal to be transmitted, the signal to be transmitted is divided into multiple groups of data to be processed; For any data to be processed, a sub-composite waveform of the data to be processed is generated according to each preset frequency in the preset frequency set; wherein, the preset frequency set includes N mutually independent frequency sets; any set of frequency sets includes M orthogonal subcarriers, and the center frequency interval of different frequency sets is greater than the channel coherence bandwidth; N and M are integers greater than or equal to 2; According to a preset frame structure, the sub-composite waveforms corresponding to each data to be processed are combined with a preset preamble and multiple guide frames to obtain the target transmission signal and transmit it. The preset frame structure includes one preamble, multiple data symbols, and multiple guide frames. The multiple guide frames and the multiple data symbols are time-division interleaved. Each data symbol is used to transmit the corresponding sub-composite waveform. The guide frame is a known signal segment that is periodically inserted between data symbols in the frame structure. The step of dividing the signal to be transmitted into multiple groups of data to be processed includes: The number of bits included in any set of data to be processed is calculated based on a preset modulation order; wherein the modulation order represents the amount of information carried by any set of data to be processed; and the preset modulation order is the number of orthogonal subcarriers in any set of frequencies. Starting from the beginning position of the signal to be transmitted, each consecutive number of bits is divided into a group of data to be processed; The step of generating sub-composite waveforms of the data to be processed based on each preset frequency in a preset frequency set includes: Convert the data to be processed into a filtering index; For any set of frequencies, select the target orthogonal subcarriers corresponding to the selection index; The sub-composite waveform is obtained by superimposing the target orthogonal subcarriers corresponding to all frequency sets.

2. The method according to claim 1, characterized in that, The step of converting the data to be processed into a filtering index includes: Transform the data to be processed into data to be mapped; The index of the data to be mapped is determined according to the preset mapping rules.

3. The method according to claim 1 or 2, characterized in that, The duration of the preamble synchronization header is greater than or equal to N times the duration of the data symbol, where N is an integer greater than or equal to 2. The duration of the pilot frame is greater than or equal to the maximum multipath delay spread of the channel through which the target transmitted signal is transmitted.

4. A signal receiving method, characterized in that, The method includes: In response to acquiring the signal to be received, the target start frame of the signal to be received is determined; Based on the target start frame and the pre-acquired frame structure, the signal to be received is initially frequency corrected to obtain an initial received signal; wherein, the pre-acquired frame structure includes one preamble, multiple data symbols, and multiple guide frames; the multiple guide frames and the multiple data symbols are time-division interleaved; each data symbol is used to transmit the corresponding sub-composite waveform; the guide frame is a known signal segment periodically inserted between data symbols in the frame structure; Phase compensation is performed on the initial received signal based on the pre-acquired frame structure; Based on the pre-acquired frequency set parameters, the initial received signal after phase compensation is demodulated to obtain the target received signal; the frequency set parameters include N mutually independent frequency sets; any set of frequencies includes M orthogonal subcarriers; N and M are integers greater than or equal to 2.

5. The method according to claim 4, characterized in that, Determining the target start frame of the signal to be received includes: In response to the ratio of the spectral peak to the noise floor of the acquired signal being received being greater than a preset ratio threshold, the starting frame of the signal being received is taken as the initial starting frame. Starting from the initial start frame, sampling is performed within the preamble duration, and the cross-correlation characteristics of each sampling point are calculated; where the preamble duration refers to the duration of the preamble synchronization header in the pre-acquired frame structure; The point with the largest cross-correlation feature is taken as the target starting frame of the signal to be received.

6. The method according to claim 4, characterized in that, The step of performing preliminary frequency correction on the signal to be received based on the target starting frame and the pre-acquired frame structure to obtain the initial received signal includes: Starting from the target start frame, obtain the measurement frequency of the preamble synchronization head during the preamble duration; Calculate the frequency offset between the pre-acquired reference frequency of the preamble sync head and the measured frequency; Based on the frequency offset, the signal to be received is initially frequency corrected to obtain the initial received signal.

7. The method according to claim 4, characterized in that, The step of performing phase compensation on the initial received signal according to the pre-acquired frame structure includes: The measured pilot frame frequency of each pilot frame in the initial received signal is obtained; the pilot frame is a known signal segment periodically inserted between data symbols in the frame structure. For any pilot frame, calculate the frequency offset correction between the measured pilot frame frequency and the reference pilot frame frequency; The phase of the data symbol corresponding to the pilot frame is rotated according to the frequency offset correction amount to complete the phase compensation of the initial received signal.

8. The method according to claim 7, characterized in that, The step of performing phase rotation on the data symbols corresponding to the pilot frame based on the frequency offset correction amount includes: Phase rotation is performed on the data symbols in the frame following the preamble frame; wherein, the phase rotation of the data symbols in the first frame is performed according to the frequency offset of the preamble sync head.

9. The method according to claim 4, characterized in that, The step of demodulating the initial received signal after phase compensation based on pre-acquired frequency set parameters to obtain the target received signal includes: The initial received signal after phase compensation is converted into a frequency domain received signal; Based on the pre-acquired frequency mapping rules, the target orthogonal subcarrier corresponding to any data symbol in the frequency domain received signal is determined; The target received signal is obtained by inverse mapping based on the target orthogonal subcarriers.

10. The method according to claim 9, characterized in that, The step of determining the target orthogonal subcarrier corresponding to any data symbol in the frequency domain received signal according to a pre-acquired frequency mapping rule includes: For any data symbol, traverse the M candidate symbol indices; the M candidate symbol indices are determined according to the frequency mapping rules preset by the transmitter. For any candidate symbol index, determine its N diversity frequency points in the N frequency sets according to the frequency mapping rule; On the frequency domain received signal, find the frequency positions corresponding to the N diversity frequency points respectively; Extract the corresponding signal energy based on each of the aforementioned frequency positions; The signal energy corresponding to each frequency position is extracted and accumulated to obtain the total energy corresponding to the preset orthogonal subcarriers; Compare the total energy corresponding to each symbol, and take the symbol with the largest total energy as the target orthogonal subcarrier.

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