Power line carrier signal modulation method based on channel measurement

Abstract

This invention relates to a power line carrier signal modulation method based on channel measurements. In this method, the source node transmits a first signal covering the entire target spectrum, then receives the signal-to-noise ratio (SNR) data for each resource group transmitted by the destination node. Finally, the modulation mode is configured according to the SNR of each resource group, thereby achieving dynamic configuration of the resource group modulation mode. This allows for adaptation to complex and variable power line channel environments. The dynamic SNR-based modulation mode configuration, on the one hand, fully utilizes actual channel quality measurement information to achieve maximum transmission rate; on the other hand, the modulation mode matches the channel quality, resulting in strong noise immunity and improved signal transmission reliability and accuracy.

Description

Technical Field

[0001] This invention relates to the field of power line carrier communication technology, and in particular to a power line carrier signal modulation method based on channel measurement. Background Technology

[0002] Power line communication (PLC) utilizes existing power lines for data transmission, eliminating the need for dedicated communication lines and significantly reducing infrastructure construction costs. It fully leverages the extensive coverage of the power network, enabling convenient plug-and-play communication and boasting numerous advantages such as low cost, wide coverage, and rapid deployment. Over the years, PLC technology has evolved from early narrowband PLC to broadband PLC based on Orthogonal Frequency Division Multiplexing (OFDM) technology, and is now moving towards a new stage of broadband and wireless dual-mode PLC integration. It has been widely applied and plays a vital role in numerous fields such as smart homes, smart grids, and industrial automation.

[0003] Currently, the core development direction of next-generation power line communication technology focuses on significantly improving communication speed. In existing broadband power line communication systems, OFDM technology effectively overcomes the multipath effect and frequency-selective fading problems in power line channels by decomposing high-speed data streams into multiple low-speed sub-data streams and using mutually orthogonal subcarriers for parallel transmission, greatly improving signal transmission reliability and spectrum utilization. However, in existing broadband power line communication technologies, the subcarriers use a fixed modulation mode, meaning that the subcarriers modulate and demodulate signals according to a pre-set fixed modulation mode. But the power line channel environment is complex and variable, affected by many factors such as the start-up and shutdown of various electrical equipment, fluctuations in power grid load, and external electromagnetic interference. The fixed modulation mode cannot dynamically adjust the subcarrier modulation mode according to changes in the power line channel environment, limiting further improvements in communication speed. Therefore, how to optimize the subcarrier modulation mode to adapt to the complex and variable power line channel environment has become an urgent problem to be solved. Summary of the Invention

[0004] In view of this, the present application provides a power line carrier signal modulation method based on channel measurement to solve at least one problem existing in the background art.

[0005] In a first aspect, embodiments of this application provide a power line carrier signal modulation method based on channel measurements, applied to a source node, the method comprising:

[0006] A first signal is sent to the power line channel so that the destination node receives the first signal transmitted via the power line and calculates the signal-to-noise ratio of each resource group; wherein, the first signal is a full-band signal covering the target spectrum range, and the full-band signal is composed of all subcarriers within the target spectrum range; all subcarriers are divided into multiple resource groups according to a preset rule, and each resource group contains multiple consecutive subcarriers; the first signal is composed of a first preset number of synchronization symbols;

[0007] The second signal sent by the destination node is received and parsed to obtain the signal-to-noise ratio of each resource group; the second signal includes the signal-to-noise ratio data of each resource group.

[0008] Configure the modulation mode of each resource group according to the signal-to-noise ratio of each resource group to transmit the target signal.

[0009] Secondly, embodiments of this application provide a power line carrier signal modulation method based on channel measurements, applied to a target node, the method comprising:

[0010] The system receives a first signal transmitted via a power line channel and calculates the signal-to-noise ratio (SNR) to obtain the SNR of each resource group. The first signal is a full-band signal covering the target spectrum range, and the full-band signal consists of all subcarriers within the target spectrum range. All subcarriers are divided into multiple resource groups according to a preset rule, and each resource group contains multiple consecutive subcarriers. The first signal consists of a first preset number of synchronization symbols.

[0011] The destination node sends a second signal to enable the source node to obtain the signal-to-noise ratio of each resource group and configure the modulation mode of each resource group; the second signal includes the signal-to-noise ratio data of each resource group.

[0012] In this embodiment, the source node transmits a first signal covering the entire target spectrum, then receives the signal-to-noise ratio (SNR) of each resource group calculated by the destination node based on the first signal. Finally, it configures the modulation mode according to the SNR of each resource group, thereby achieving dynamic configuration of the resource group modulation mode. This adapts to the complex and ever-changing power line channel environment. Dynamically configuring the modulation mode based on the SNR allows for full utilization of actual channel quality measurements to achieve maximum transmission rate. Furthermore, the modulation mode matches the channel quality, providing strong noise immunity and improving the reliability and accuracy of signal transmission.

[0013] Additional aspects and advantages of this application 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 application. Attached Figure Description

[0014] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments of this application and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0015] Figure 1 A flowchart of a power line carrier signal modulation method based on channel measurement applied to a source node, provided in an embodiment of this application;

[0016] Figure 2 This is a schematic diagram of the power line communication system topology provided in an embodiment of this application;

[0017] Figure 3 A flowchart illustrating a power line carrier signal modulation method based on channel measurement applied to a destination node, as provided in an embodiment of this application. Detailed Implementation

[0018] To make the technical solution and beneficial effects of the present invention more apparent and understandable, a detailed description is provided below by listing specific embodiments. Unless otherwise defined, the technical and scientific terms used herein have the same meanings as those in the technical field to which this application pertains.

[0019] With the widespread deployment of power line communication and other carrier communication systems in smart grids, smart homes, and industrial automation, the requirements for real-time and reliable data transmission in communication systems are increasing. The core of OFDM modulation technology is to decompose a high-speed data stream into multiple orthogonal parallel low-speed subcarrier signals for transmission. Among these, the subcarrier modulation mode is a key factor affecting communication transmission performance, directly determining the signal's noise immunity and transmission rate. For example, Binary Phase Shift Keying (BPSK) has the strongest noise immunity but weak data transmission capability, transmitting 1 bit per subcarrier; Quadrature Phase Shift Keying (QPSK) has slightly better noise immunity, transmitting 2 bits per subcarrier, thus improving transmission capability; 16-Quadrature Amplitude Modulation (16QAM) has relatively weak noise immunity, but transmits 4 bits per subcarrier, offering the strongest data transmission capability under good channel conditions. However, in existing broadband power line communication technologies, subcarriers typically employ fixed modulation modes, meaning that subcarriers modulate and demodulate signals according to a pre-set fixed modulation mode. Fixed modulation modes cannot dynamically adjust the modulation mode of subcarriers according to changes in the power line channel environment, which limits further improvements in communication rates.

[0020] In view of this, this invention proposes a power line carrier signal modulation method based on channel measurement. This method obtains the signal-to-noise ratio (SNR) of each resource group by transmitting a signal containing all subcarriers. Then, based on the SNR of each resource group, the modulation mode of the resource group is configured to transmit the target signal. This invention can dynamically modulate resource group configuration parameters through channel measurement, thereby adapting to changes in channel conditions and improving communication rate and success rate. Simultaneously, the resource group configuration parameter approach reduces configuration complexity, avoids reporting and storing excessive channel quality information, and further improves the accuracy and robustness of the measurement.

[0021] The following detailed description, in conjunction with the accompanying drawings, of the power line carrier signal modulation method based on channel measurement provided by the present invention through specific embodiments and application scenarios, will illustrate this invention in detail.

[0022] For HPLC systems, industry technical specifications detail the physical layer, data link layer, and application layer protocols of broadband carrier communication standards, as well as related testing specifications. In these specifications, the signal to be transmitted is typically achieved through sequential transmission of individual PPDU (Physical Protocol Data Unit) frames. A PPDU frame typically contains a preamble, a frame control (FC) signal, and a payload (PL). The preamble is used for frame synchronization and channel estimation. The FC signal describes basic frame information, such as the modulation mode of the payload, subcarrier distribution, and payload length, facilitating subsequent parsing of the payload signal at the receiving end. The payload describes the actual data to be transmitted. Generally, the preamble symbol consists of multiple synchronization symbols. For example, in power line carrier communication protocols, the frame preamble includes 10.5 SYCNP synchronization symbols and 2.5 SYNCM synchronization symbols. The SYNCP and SYNCM synchronization symbols are out of phase, and each SYCNP and SYNCM synchronization symbol includes 1024 sample points. It should be noted that in power line carrier communication, synchronization symbols are crucial for signal synchronization. They typically have specific amplitude, phase, and other structures. Synchronization symbols determine the start time of the signal, achieving time synchronization and ensuring accurate demodulation of subsequent data symbols.

[0023] Figure 1 This is a flowchart illustrating a power line carrier signal modulation method based on channel measurements applied to the source node, as provided in an embodiment of this application. Figure 1 As shown, the modulation method in this application embodiment includes:

[0024] S1. Send the first signal to the power line channel.

[0025] Specifically, the source node sends a first signal into the power line channel, enabling the destination node to receive the first signal transmitted via the power line channel and calculate the signal-to-noise ratio (SNR) of each resource group. In this embodiment, the source node sends a first signal to the destination node, and the destination node can calculate the SNR of each resource group based on the first signal transmitted via the channel, thereby obtaining the channel quality information between the source and destination nodes. It should be noted that, since power line channels are not mutually exclusive, the channel quality information between the destination and source nodes cannot be derived from the channel quality information between the source and destination nodes.

[0026] The first signal is composed of a first preset number of synchronization symbols; that is, in the time domain, the first signal is composed of the first preset number of synchronization symbols. The first signal is a full-band signal covering the target spectrum range, meaning it is a signal composed of all subcarriers within the target spectrum range. The target spectrum range is determined based on the communication protocol and is not limited in this application. For example, if the maximum spectrum range in a power line communication protocol is 0.7MHz-12MHz, and the number of subcarriers within that range is 512, then if the target spectrum range is equal to the maximum spectrum range in the communication protocol, then each synchronization symbol in the first signal is composed of 512 subcarriers. It should be noted that the target spectrum range can be the maximum spectrum range in the communication protocol or a specific frequency band range; this application does not limit it.

[0027] Compared to traditional power line carrier signals that include frame preambles, frame control, and data symbols, the first signal in this embodiment consists only of synchronization symbols, and each synchronization symbol is composed of a second preset number of subcarriers. On the one hand, the synchronization symbols are singular and standardized, reducing the complexity of source node signal generation and processing (load signals and frame control signals require encoding, interleaving, and other processing), thus reducing hardware resource consumption. On the other hand, it enhances measurement accuracy; the synchronization symbols cover all subcarriers, comprehensively reflecting channel characteristics, avoiding interference from other symbols, and making the signal-to-noise ratio more accurate. It should be noted that the power line carrier communication protocol in this embodiment is not limited to a specific protocol, but can be configured and selected according to specific application scenarios, technical requirements, and industry standard requirements.

[0028] In power line carrier communication, by transmitting a first signal covering all subcarriers, channel quality information within the target spectrum range corresponding to all subcarriers can be obtained, providing reliable data for the subsequent modulation mode configuration of subcarriers. Optionally, all subcarriers are divided into multiple resource groups according to a preset rule, with each resource group including multiple subcarriers. Further, the preset rule is to equally divide all subcarriers into multiple resource groups, with each resource group including multiple consecutive subcarriers, and correspondingly, each resource group includes the same number of subcarriers. Optionally, the preset rule can also be to divide all subcarriers into multiple resource groups, with each resource group including a different number of subcarriers. How the preset rule allocates subcarriers in the resource groups can be adjusted according to the actual situation, and this application is not limited thereto. In the embodiments of this application, by dividing the subcarriers into resource groups, the data storage space and the amount of data transmitted can be reduced, thereby reducing the amount of data transmitted by the destination node, and the signal-to-noise ratio of each resource group can be sent to the source node more accurately and quickly. For example, in power line carrier communication, the communication frequency band ranges from 0.7MHz to 12MHz, corresponding to 512 subcarriers. Sending the signal-to-noise ratio (SNR) of each subcarrier to the source node would require significant storage space, result in a large data volume, and lead to long transmission times, impacting the channel measurement rate. In this embodiment, the subcarriers within each resource group are consecutive; that is, if all subcarriers in the communication protocol are numbered sequentially by frequency, then the subcarriers within each resource group are consecutively numbered. It is understood that adjacent subcarriers will influence each other, and the consecutive subcarriers within each resource group result in a more accurate and realistic SNR. For example, if there are 512 subcarrier frequencies from smallest to largest, the corresponding numbers are 1 to 512. If divided into 16 equal resource groups, the subcarrier numbers in each resource group would be 1-32, 33-61…481-512.

[0029] Optionally, the first signal can be broadcast to the power line channel. By broadcasting, the first signal can be received indiscriminately by all destination nodes in the power line network, simplifying the address information of the destination nodes. The first signal contains only synchronization symbol data, reducing signal length and transmission time. Furthermore, since it only contains synchronization symbol data, the destination nodes do not need to perform subsequent parsing or other processing, thus improving their processing speed. It should be noted that in power communication systems, traditional point-to-point communication requires adding a destination address field (such as a MAC address) to the signal, consuming additional bandwidth; the nodes are connected in a tree-like topology, and point-to-point communication generally requires carrying address information.

[0030] Figure 2 This is a schematic diagram of the power line communication system topology provided in an embodiment of this application. Figure 2As shown, the nodes in the topology diagram mainly include the Central Coordinator (CCO), proxy nodes (PCO), and stations (STA). STAs need to communicate with the CCO or PCO via power lines, and the PCO can forward messages from lower-level STAs. Taking STA8 as an example, its proxy node is PCO3. Messages sent by STA8 must first be forwarded through PCO3, and then through PCO1 before reaching the CCO. Taking PCO1 as an example, PCO1 broadcasts its first signal, which can be received indiscriminately by its downlink nodes (STA4, PCO2, PCO3, STA5) and uplink nodes (CCO).

[0031] S2. Receive and parse the second signal sent by the destination node to obtain the signal-to-noise ratio of each resource group.

[0032] In this embodiment, the second signal includes the signal-to-noise ratio (SNR) data for each resource group. Specifically, the destination node performs synchronization, FFT, and other processing on the first signal transmitted via the power line channel, calculates the signal energy and noise energy of each subcarrier, and then obtains the SNR of each resource group based on the signal energy and noise energy of each subcarrier. The SNR of each resource group is the channel quality information from the source node to the destination node. The destination node uses the SNR of each resource group as payload data, performs coding and interleaving processing to generate the second signal, and sends it to the source node. The source node receives and parses the second signal, thereby obtaining the channel quality information corresponding to the source node to the destination node.

[0033] S3. Configure the modulation mode of each resource group according to the signal-to-noise ratio of each resource group to transmit the target signal.

[0034] It should be noted that the target signal here is also a full-band signal. In this embodiment, the modulation mode of each resource group in the target signal is configured based on the signal-to-noise ratio (SNR) of each resource group, thereby maximizing the transmission capacity of each resource group. Specifically, on the one hand, the target signal uses all subcarriers, thereby improving spectrum utilization efficiency; on the other hand, the modulation mode is dynamically configured based on the SNR, which maximizes the utilization of the transmission capacity of the resource group and also reduces the bit error rate; finally, the dynamic adaptation mechanism can also adapt to the time-varying characteristics of the power line channel and maintain stable communication. Optionally, the modulation mode in this embodiment can be QPSK, BPSK, or 16QAM. It should be noted that the number of bits transmitted by each subcarrier is related to the modulation mode of each subcarrier, and the modulation mode is related to the SNR. For example, QPSK, BPSK, and 16QAM are suitable for different SNR environments. BPSK is suitable for low SNR, with each subcarrier transmitting 1 bit, which has the strongest anti-interference capability but weak transmission capability; 16QAM is suitable for high SNR, with each subcarrier transmitting 4 bits, which has weak anti-interference capability but strong transmission capability. In this embodiment, the modulation mode based on the dynamic configuration of resource groups according to the signal-to-noise ratio can improve the transmission capability and also has a strong anti-interference capability.

[0035] As an optional specific implementation, S3 includes:

[0036] The signal-to-noise ratio (SNR) of each resource group is compared with the SNR threshold of each modulation mode to determine the modulation mode of each resource group for transmitting the target signal.

[0037] Specifically, if the signal-to-noise ratio (SNR) of a resource group is greater than or equal to a first SNR threshold and less than a second SNR threshold, then the modulation mode of the resource group is the modulation mode corresponding to the first SNR threshold. If the SNR of a resource group is less than the minimum SNR threshold among all modulation modes, then the resource group is idle. If the SNR of a resource group is greater than the maximum SNR threshold among all modulation modes, then the modulation mode of the resource group is the modulation mode corresponding to the maximum SNR threshold. It should be noted that the first and second SNR thresholds in this embodiment are not specific numerical values, but rather represent the first and second SNR thresholds corresponding to when the SNR of a resource group is between two SNR thresholds. For example, if the signal-to-noise ratio (SNR) thresholds for BPSK, QPSK, and 16QAM are 0dB, 2dB, and 10dB respectively, and the SNR threshold of resource group REG1 is less than 0dB, then REG1 is idle; if it is greater than 0 and less than 2, then the modulation mode of REG1 is BPSK, with the corresponding first SNR threshold of 0 and the second SNR threshold of 2; if it is greater than 2 and less than 10, then the modulation mode of REG1 is QPSK, with the corresponding first SNR threshold of 2 and the second SNR threshold of 10; if it is greater than 10, then the modulation mode of REG1 is 16QAM. It can be understood that if a resource group is idle, none of the subcarriers within that resource group transmit bits; if a resource group has a defined modulation mode, then all subcarriers within that resource group transmit bits according to that modulation mode. For example, if the modulation mode of REG1 is QPSK, since each symbol in QPSK can transmit 2 bits, each subcarrier in REG1 can transmit 2 bits. The total number of bits transmitted is equal to the number of subcarriers in REG1 multiplied by the number of bits that each subcarrier can transmit. It should be noted that the target signal here refers to the data payload signal to be transmitted, which consists of multiple OFDM symbols. Each OFDM symbol transmits bits based on the modulation scheme of the resource group. The signal-to-noise ratio (SNR) threshold of the modulation scheme represents the SNR at which the modulation scheme can reliably transmit signals. If the SNR of a resource group is greater than the SNR threshold of the modulation scheme, it indicates that the resource group can reliably and stably transmit signals under that modulation scheme.

[0038] As an optional specific implementation, S3 may further include:

[0039] The signal-to-noise ratio of each resource group is corrected according to the preset number of diversity operations to obtain the corrected signal-to-noise ratio of each resource group;

[0040] Correspondingly, the corrected signal-to-noise ratio of each resource group is compared with the signal-to-noise ratio threshold of each modulation mode to determine the modulation mode of each resource group in order to transmit the target signal.

[0041] In power line carrier communication, the complex and variable channel environment leads to a significant decrease in the reliability of single signal transmission. To address this, diversity copying and interleaving techniques are typically used in power line carrier communication to generate multiple independent copies of the frame control signal and data payload signal. This redundancy in the spatial, temporal, or frequency domains reduces the risk of transmission failure. The receiver utilizes the independent fading of each copy and combines the signals through calculation to achieve reliable signal reception. In this embodiment, the signal-to-noise ratio (SNR) of each resource group is calculated based on the synchronization symbol. Since the transmission of the synchronization symbol does not employ diversity copying, the channel quality information obtained from the synchronization symbol differs from the actual signal's channel quality information due to the presence or absence of diversity copying. For example, if the SNR of the synchronization symbol is 10 dB, the actual SNR of the payload data symbol after four diversity copies may reach as high as 16 dB. Therefore, this embodiment corrects the SNR of each resource group by pre-setting the number of diversity operations. This allows the corrected SNR result obtained based on the synchronization symbol to more closely reflect the actual transmission scenario of the data payload symbol, thus providing more accurate channel quality information for the dynamic allocation of modulation modes.

[0042] Optionally, based on the maximum ratio combining method, the signal-to-noise ratio (SNR) of each resource group is corrected according to a preset number of diversity operations to obtain the corrected SNR for each resource group. Specifically, the maximum ratio combining method is used for correction using the following formula:

[0043] SNR'=SNR sync +10log 10 N

[0044] Where SNR' is the corrected signal-to-noise ratio of the resource group, SNR sync Let N be the signal-to-noise ratio of the resource group, and N be the preset diversity factor. It should be noted that this formula is a decibel-domain formula, with the unit being dB.

[0045] It should be noted that the signal-to-noise ratio (SNR) of the maximum ratio combining method in the linear domain is equivalent to the sum of the SNRs of each branch, that is:

[0046] SNR linear =N×SNR sync, linear

[0047] Among them, SNR linear For the corrected signal-to-noise ratio of the linear domain resource group, SNR sync, linear Let N be the signal-to-noise ratio of the linear domain resource group, and N be the preset diversity factor. The decibel domain formula is obtained by converting the logarithmic ratio to the decibel (dB) domain using a base-10 logarithmic ratio.

[0048] In this embodiment, maximum ratio combining is based on the superposition of signal-to-noise ratios (SNR) after a preset number of diversity operations. This allows the combined signal-to-noise ratio to more closely approximate the actual transmission channel environment of the data payload symbols, enhancing the reliability and accuracy of the payload data channel quality information. Other combining methods can also be used in this embodiment, and this application is not limited thereto. Furthermore, the modified SNR of each resource group is compared with the SNR threshold value of each modulation mode. The specific comparison method is consistent with the comparison method of the SNR of the resource group and the SNR threshold value of each modulation mode in the above embodiments, except that the SNR of each resource group is transformed into the modified SNR of each resource group, which will not be elaborated further here.

[0049] It should be noted that the preset diversity number can be set or configured according to the communication protocol or actual communication, and this application does not limit it. Furthermore, the preset diversity number here can include a preset fixed diversity number, or it can include multiple preset diversity numbers. For example, if there are multiple diversity numbers, the corrected signal-to-noise ratio for each diversity number is calculated separately, and the modulation mode for each diversity number is determined. Then, the diversity number and modulation mode are configured based on the minimum number of transmitted symbols.

[0050] In this embodiment, if the source node is the parent node, then the corresponding destination node is the child node; or if the source node is the child node, then the corresponding destination node is the parent node. Data from the child node is either directly sent to the parent node or forwarded by the parent node. It should be noted that when data from the child node is forwarded by the parent node, the child node essentially sends a signal carrying the data and destination address to the parent node. The parent node receives and parses the signal, and then forwards the data carrying the child node's address, destination address, and data to the parent node. It should also be noted that power line carrier communication systems have a tree topology; a parent node typically corresponds to multiple child nodes, but a child node typically corresponds to one parent node. For example... Figure 2 In this context, when the source node is PCO1 and the destination node is STA4, the source node is the parent node and the destination node is the child node; when the source node is PCO1 and the destination node is CCO, the source node is the child node and the destination node is the parent node.

[0051] As one optional implementation, the source node is the parent node, and the destination node is the child node. Furthermore, after S3, it also includes:

[0052] Obtain the modulation mode of each resource group corresponding to multiple destination nodes;

[0053] Based on the modulation mode of each resource group corresponding to multiple destination nodes, all resource groups are allocated to multiple destination nodes to transmit target signals to multiple destination nodes simultaneously.

[0054] In this embodiment, the source node obtains the modulation mode of each resource group corresponding to multiple destination nodes. By combining these modulation modes, it allocates all resource groups in the frequency domain to multiple destination nodes, thus allocating frequency domain resources to different destination nodes and enabling simultaneous data transmission to multiple destination nodes. This achieves maximum transmission rate for resource groups and allows the source node to simultaneously transmit signals to multiple users. Multiple users are separated in the frequency domain but simultaneously transmitted in the time domain, thereby improving communication speed. It should be noted that the multi-user transmission in this embodiment is completely different from broadcast transmission. Broadcast transmission cannot distinguish the needs of different users and has low spectrum utilization; the simultaneous multi-user transmission in this embodiment allocates all subcarriers to different users to achieve parallel transmission, satisfying the needs of different users.

[0055] In existing power line carrier communication technologies, a fixed mode is typically used, where all subcarriers use a fixed modulation mode and are centrally allocated to a single user for one-to-one transmission. This transmission method, due to the fixed modulation mode of the subcarriers and their centralized service to a single user, can better resist noise interference in the power line environment through a relatively uniform and stable signal processing approach, ensuring the accuracy and stability of data transmission. However, if a one-to-multiple user transmission mode is adopted under a fixed modulation mode, the subcarriers are highly susceptible to noise interference due to the complexity of the power line environment. When multiple users share these subcarriers, the signal received by each user will be affected by noise to varying degrees, leading to deviations in demodulation results, severely impacting communication quality, and even causing data loss or incorrect transmission. The embodiments of this application, by precisely configuring the modulation mode based on each user's channel information, can fully consider the differences in the channel environment and noise variations of different users. Based on this, the subcarriers are rationally allocated to multiple users, allowing the modulation mode to dynamically adapt to noise changes and effectively reduce noise interference to the signal. Even when multiple users share subcarriers, each user can receive an accurate and clear signal, thus achieving efficient, stable, and reliable transmission among multiple users and significantly improving the signal communication rate. It should be noted that this embodiment combines channel quality information to allocate frequency domain resources to different users, thereby improving frequency domain utilization and allowing more data to be transmitted within the same spectrum bandwidth. Simultaneously, multiple users share channel time domain resources, and multiple users can share synchronization signals, reducing synchronization time and waiting time, and improving the system's communication rate.

[0056] In this embodiment, the source node transmits a first signal covering the entire target spectrum, then receives the signal-to-noise ratio (SNR) of each resource group calculated by the destination node based on the first signal. Finally, it configures the modulation mode according to the SNR of each resource group, thereby achieving dynamic configuration of the resource group modulation mode. This adapts to the complex and ever-changing power line channel environment. Dynamically configuring the modulation mode based on the SNR allows for full utilization of actual channel quality measurements to achieve maximum transmission rate. Furthermore, the modulation mode matches the channel quality, providing strong noise immunity and improving the reliability and accuracy of signal transmission.

[0057] Figure 3 This is a flowchart illustrating a power line carrier signal modulation method based on channel measurement applied to a destination node, as provided in an embodiment of this application. Figure 3 As shown, the modulation method in this application embodiment includes:

[0058] S100: Receive the first signal transmitted via the power line channel and calculate the signal-to-noise ratio to obtain the signal-to-noise ratio of each resource group.

[0059] The first signal is transmitted by the source node, specifically, it is broadcast by the source node so that different destination nodes can receive it. The first signal is a full-band signal covering the target spectrum range, and it consists of all subcarriers within the target spectrum range. All subcarriers are divided into multiple resource groups according to a preset rule, and each resource group contains multiple consecutive subcarriers. The first signal consists of a first preset number of synchronization symbols.

[0060] S200: Send a second signal to the power line channel so that the source node can obtain the signal-to-noise ratio of each resource group and configure the modulation mode of each resource group.

[0061] Specifically, the second signal includes the signal-to-noise ratio (SNR) data for each resource group. The destination node sends the second signal to the power line channel, thereby enabling the source node to obtain the SNR of each resource group. Then, the source node configures the modulation mode of each resource group based on the acquired SNR data.

[0062] Optionally, S100 includes:

[0063] S110: Receive the first signal transmitted via the power line channel and synchronize it to obtain the synchronization symbol after transmission via the channel.

[0064] In this embodiment of the application, the first signal is composed of synchronization symbols. By synchronizing the received signal, each synchronization symbol in the first signal can be obtained, and channel quality information can be obtained based on the synchronization symbols.

[0065] S120. Perform FFT processing on the synchronization symbols transmitted through the channel to obtain full-band frequency domain data.

[0066] Specifically, after successful synchronization, each synchronization symbol is obtained, and FFT processing is performed on the synchronization symbol to convert the time-domain synchronization symbol into frequency-domain data, thereby obtaining full-band frequency-domain data; the full-band frequency-domain data is the frequency-domain data of all subcarriers.

[0067] S130. Calculate the signal energy and noise energy of each subcarrier based on the full-band frequency domain data.

[0068] Specifically, the signal energy of each subcarrier can be obtained by taking the amplitude or the square of the modulus in the complex form of the frequency domain; the noise energy can be obtained by filtering the frequency domain data and then calculating the difference before and after filtering. This application is based on full-band frequency domain data, thus obtaining the signal energy and noise energy of each subcarrier, thereby providing data support for calculating the signal-to-noise ratio of each resource group.

[0069] S140. Obtain the signal-to-noise ratio of each resource group based on the signal energy and noise energy of each subcarrier.

[0070] As an optional specific implementation, S140 includes:

[0071] If the first preset number is greater than or equal to two, then FFT processing is performed on each synchronization symbol, and correspondingly, multiple full-band frequency domain data are obtained.

[0072] The average signal energy and average noise energy of each subcarrier are obtained by averaging the signal energy and noise energy of each subcarrier based on multiple full-band frequency domain data.

[0073] The signal-to-noise ratio of each resource group is obtained based on the average signal energy and average noise energy of each subcarrier.

[0074] In this embodiment, the average signal energy and average noise energy of the subcarriers are obtained through multiple synchronization symbols, resulting in a more accurate signal-to-noise ratio (SNR) for the resource group. In this embodiment, the accuracy of channel quality information directly determines the accuracy of modulation mode allocation. Averaging across multiple subcarriers yields more accurate signal and noise energy data for the subcarriers, leading to a more accurate SNR for the resource group.

[0075] As an optional specific implementation, S140 includes:

[0076] According to the preset calculation rules, the signal energy and noise energy of each resource group are calculated based on the signal energy and noise energy of each subcarrier;

[0077] The signal-to-noise ratio of each resource group is calculated based on the signal energy and noise energy of each resource group.

[0078] In this embodiment, the calculation rules for the signal energy and noise energy of each resource group (such as taking the average, maximum, or minimum value) directly affect the estimated signal-to-noise ratio (SNR) of the resource group. The preset calculation rules in this embodiment can be adjusted according to actual conditions. For example, for unstable or poorly conditioned channels, the signal energy of each resource group is the maximum signal energy of the subcarriers contained within the resource group, and the noise energy is the maximum noise energy of the contained subcarriers. The resulting SNR reflects the worst-case scenario, allowing subsequent modulation to select a modulation mode with stronger noise resistance, thus reducing the impact of noise on signal demodulation. As an optional implementation, the preset calculation rule is that the signal energy of each resource group is equal to the average signal energy of the subcarriers contained within the resource group, and the noise energy of each resource group is equal to the average noise energy of the subcarriers contained within the resource group. By taking the average value, this embodiment effectively smooths the energy fluctuations of each subcarrier within the resource group, accurately reflects the overall statistical characteristics of the signal and noise, and thus obtains a more stable and reliable SNR result.

[0079] As an optional specific implementation, the modulation method of this application embodiment further includes:

[0080] Receive the first signal transmitted via the power line channel a preset number of times and calculate the signal-to-noise ratio to obtain the signal-to-noise ratio of each resource group at different times;

[0081] The signal-to-noise ratio (SNR) of each resource group at different times is filtered to obtain the filtered SNR of each resource group. The filtering process is performed iteratively on multiple SNRs to reduce the impact of the current SNR on the historical SNR.

[0082] Correspondingly, the destination node sends a second signal so that the source node can obtain the filtered signal-to-noise ratio of each resource group and configure the modulation mode of each resource group.

[0083] Because the power line channel environment is complex and variable, and exhibits periodic time-varying characteristics in the short term, channel quality measurements require combining measurement results from multiple different times and filtering to obtain accurate channel quality information. In this embodiment, by receiving a first signal a preset number of times, the signal-to-noise ratio (SNR) at different times can be obtained. Then, after filtering, an accurate filtered SNR result is finally obtained.

[0084] Specifically, filtering refers to the process of smoothing or enhancing the noise resistance of channel estimation results using specific filtering algorithms (such as moving average, alpha filtering, etc.). In this embodiment, the filtering process is not a one-time static operation, but an iterative process. By continuously performing this process at multiple signal-to-noise ratios (SNRs), the filtered result gradually stabilizes, thereby effectively reducing the impact of noise on channel estimation. That is, each time a new resource group's SNR is received, the current resource group's SNR is fused with the existing filtered channel estimation result to continuously update the filtering result, making it more stable and accurate. For example, when the SNR of the first resource group is received, the destination node uses the resource group's SNR as its corresponding filtered SNR result and uses this filtered SNR result in the filtering process of the next time step. That is, the filtered SNR result corresponding to the current time step is weighted and calculated with the SNR result corresponding to the next time step to obtain the filtered SNR result corresponding to the next time step. For example, the destination node can configure a filter, such as an alpha filter. In the alpha filter, the parameter α, the filtered result, and the result of the previous filtering are used as variables. The parameter α is used to control the weight of historical data during the prediction process. If the signal-to-noise ratio of the current measurement is found to be significantly different from that of the historical measurements, the value of parameter α can be adjusted to reduce the impact of the current channel measurement on the overall result.

[0085] As an optional implementation, the product of the preset number of times and the first preset quantity is greater than or equal to the first preset threshold. In the embodiments of this application, the accuracy of the signal-to-noise ratio (SNR) result is strongly correlated with the number of statistics; the more symbols, i.e., the larger the first preset quantity, the more accurate the single SNR. However, since the average SNR is unbiased, an accurate SNR can be obtained even with two symbols as the number of statistical times increases. In the embodiments of this application, by ensuring that the product of the preset number of times and the first preset quantity is greater than or equal to the first preset threshold, the SNR result can be made more accurate. The first preset threshold is adjusted based on simulation results and actual communication conditions. For example, if the ultimate goal is that the difference between the true SNR and the actual SNR does not exceed 0.5 dB with a 90% probability, and the simulation result is 6 symbols or 2 symbols per measurement, and the number of measurements is greater than or equal to 3, then the first preset threshold can be set to 6.

[0086] In this embodiment, subcarriers are divided into multiple resource groups, and the signal-to-noise ratio (SNR) of each resource group is calculated based on a first signal. Finally, the SNR of each resource group is sent to the source node, thus providing accurate SNR data for configuring the modulation mode. In this embodiment, the first signal is a full-band signal covering the target spectrum and consists of synchronization symbols. Based on these synchronization symbols, the destination node can accurately obtain real-time, comprehensive power line channel information, thereby providing accurate data support for improving transmission rate and reliability.

[0087] It should be understood that, although Figure 1 and Figure 3 The steps in the flowchart are shown sequentially as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order in which these steps are executed, and they can be performed in other orders. Figure 1 and Figure 3 At least some of the steps in the process may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but may be executed at different times. The execution order of these steps or stages is not necessarily sequential, but may be executed in turn or alternately with other steps or at least some of the steps or stages in other steps.

[0088] It should be noted that the embodiments of the power line carrier signal modulation method based on channel measurement applied to the source node and the embodiments of the power line carrier signal modulation method based on channel measurement applied to the destination node provided in this application belong to the same concept; the technical features in the technical solutions described in each embodiment can be arbitrarily combined without conflict.

[0089] It should be understood that the above embodiments are exemplary and are not intended to encompass all possible implementations included in the claims. Various modifications and changes can be made to the above embodiments without departing from the scope of this disclosure. Similarly, the various technical features of the above embodiments can be arbitrarily combined to form other embodiments of the present invention that may not be explicitly described. Therefore, the above embodiments only illustrate several implementations of the present invention and do not limit the scope of protection of this patent.

Claims

1. A power line carrier signal modulation method based on channel measurement, applied to the source node, characterized in that, The methods include: A first signal is sent to the power line channel so that all destination nodes corresponding to the source node receive the first signal transmitted via the power line and calculate the signal-to-noise ratio of each resource group; wherein, the first signal is a full-band signal covering the target spectrum range, the full-band signal is composed of all subcarriers within the target spectrum range; all subcarriers are divided into multiple resource groups according to a preset rule, each resource group contains multiple consecutive subcarriers; the first signal is composed of a first preset number of synchronization symbols; The system receives and parses the second signal sent by the destination node to obtain the signal-to-noise ratio of each resource group; the second signal includes the signal-to-noise ratio data of each resource group. Based on the maximum ratio merging method, the signal-to-noise ratio of each resource group is corrected according to a preset number of diversity operations to obtain the corrected signal-to-noise ratio of each resource group; wherein, the corrected signal-to-noise ratio of the resource group is greater than the corresponding resource group signal-to-noise ratio; The modified signal-to-noise ratio of each resource group is compared with the signal-to-noise ratio threshold of each modulation mode to determine the modulation mode of each resource group in order to transmit the target signal; The preset diversity number includes a preset fixed diversity number and a preset multiple diversity number. If the preset diversity number is a preset multiple diversity number, the corrected signal-to-noise ratio of each resource group under each diversity number is calculated, and the modulation mode of each resource group under each diversity number is determined. Then, the diversity number and the corresponding modulation mode are configured based on the minimum number of transmitted symbols to transmit the target signal.

2. The power line carrier signal modulation method based on channel measurement as described in claim 1, characterized in that, The maximum ratio merging method is based on the following formula: SNR'=SNR sync +10logs 10 N, Where SNR' is the corrected signal-to-noise ratio of the resource group, SNR sync is the signal-to-noise ratio of the resource group, and N is the preset number of diversity operations.

3. The power line carrier signal modulation method based on channel measurement as described in claim 1, characterized in that, The step of configuring the modulation mode of each resource group according to the signal-to-noise ratio of each resource group to transmit the target signal includes: The signal-to-noise ratio (SNR) of each resource group is compared with the SNR threshold of each modulation mode to determine the modulation mode of each resource group for transmitting the target signal.

4. The power line carrier signal modulation method based on channel measurement as described in claim 3, characterized in that, The step of comparing the signal-to-noise ratio (SNR) of each resource group with the SNR threshold value of each modulation mode to determine the modulation mode of each resource group includes: If the signal-to-noise ratio of a resource group is greater than or equal to the first signal-to-noise ratio threshold and less than the second signal-to-noise ratio threshold, then the modulation mode of the resource group is the modulation mode corresponding to the first signal-to-noise ratio threshold. If the signal-to-noise ratio of a resource group is less than the minimum value among the signal-to-noise ratio thresholds of each modulation mode, then the resource group is idle. If the signal-to-noise ratio (SNR) of a resource group is greater than the maximum value among the SNR thresholds of each modulation mode, then the modulation mode of that resource group is the modulation mode corresponding to the maximum value among the SNR thresholds.

5. The power line carrier signal modulation method based on channel measurement as described in claim 1, characterized in that, The method further includes: Obtain the modulation mode of each resource group corresponding to multiple destination nodes; Based on the modulation mode of each resource group corresponding to multiple destination nodes, the resource group is allocated to multiple destination nodes so as to transmit the target signal to multiple destination nodes simultaneously.

6. A power line carrier signal modulation method based on channel measurement, applied to a target node, characterized in that, The methods include: The system receives a first signal transmitted via the power line channel a preset number of times and calculates the signal-to-noise ratio (SNR) to obtain the SNR of each resource group at different times. The first signal is a full-band signal covering the target spectrum range, consisting of all subcarriers within the target spectrum range. All subcarriers are divided into multiple resource groups according to a preset rule, and each resource group contains multiple consecutive subcarriers. The first signal consists of a first preset number of synchronization symbols. The signal-to-noise ratio (SNR) of each resource group at different times is filtered to obtain the filtered SNR of each resource group. The filtering process is performed iteratively on multiple SNRs to reduce the impact of the current SNR on the historical SNR. A second signal is sent to the power line channel to enable the source node to obtain the filtered signal-to-noise ratio of each resource group and configure the modulation mode of each resource group; wherein, the second signal includes the filtered signal-to-noise ratio data of each resource group; Wherein, the product of the preset number of times and the first preset quantity is greater than or equal to the first preset threshold.

7. The power line carrier signal modulation method based on channel measurement as described in claim 6, characterized in that, The process of receiving the first signal transmitted via the power line channel and calculating the signal-to-noise ratio (SNR) to obtain the SNR of each resource group includes: Receive the first signal transmitted via the power line channel and synchronize it to obtain the synchronization symbol after transmission via the channel; The synchronization symbols transmitted through the channel are subjected to FFT processing to obtain full-band frequency domain data; Calculate the signal energy and noise energy of each subcarrier based on the full-band frequency domain data; The signal-to-noise ratio of each resource group is obtained based on the signal energy and noise energy of each subcarrier.

8. The power line carrier signal modulation method based on channel measurement as described in claim 7, characterized in that, The signal-to-noise ratio (SNR) of each resource group is obtained based on the signal energy and noise energy of each subcarrier, including: If the first preset number is greater than or equal to two, then FFT processing is performed on each synchronization symbol, and correspondingly, multiple full-band frequency domain data are obtained. The average signal energy and average noise energy of each subcarrier are obtained by averaging the signal energy and noise energy of each subcarrier based on multiple full-band frequency domain data. The signal-to-noise ratio of each resource group is obtained based on the average signal energy and average noise energy of each subcarrier.

9. The power line carrier signal modulation method based on channel measurement as described in claim 7, characterized in that, The method of obtaining the signal-to-noise ratio of each resource group based on the signal energy and noise energy of each subcarrier includes: According to a preset calculation rule, the signal energy and noise energy of each resource group are calculated based on the signal energy and noise energy of each subcarrier; wherein, the preset calculation rule is that the signal energy of each resource group is equal to the average signal energy of the subcarriers contained in the resource group, and the noise energy of each resource group is equal to the average noise energy of the subcarriers contained in the resource group. The signal-to-noise ratio of each resource group is calculated based on the signal energy and noise energy of each resource group.

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