A power line carrier multi-user communication method

Abstract

The application relates to a power line carrier multi-user communication method. The method comprises the following steps: dividing each leaf node into multiple target groups based on the implementation of power line channel measurement results, and performing frequency domain resource allocation on each leaf node of each target group; then periodically broadcasting a multi-user transmission request frame to each target group; and finally receiving uplink data frames sent by each leaf node of each target group in parallel within the allocated frequency domain resources. Through frequency domain resource allocation, the embodiment of the application realizes parallel data transmission of each leaf node, reduces frame synchronization and frame waiting time on the one hand, avoids time domain resource waste, and on the other hand, based on channel measurement frequency domain allocation, can maximize the use of frequency spectrum resources, and each leaf node in the same target group jointly occupies the channel, thereby improving the transmission rate.

Description

Technical Field

[0001] This invention relates to the field of power line carrier communication, and in particular to a power line carrier multi-user communication method. Background Technology

[0002] Power line communication (PLC) utilizes existing power lines to transmit data. It requires no additional wiring and offers wide coverage, making it widely used in smart grids, smart homes, and industrial automation. Orthogonal Frequency Division Multiplexing (OFDM) technology, a key technology in PLC, divides the channel into multiple orthogonal subcarriers, each carrying data independently, effectively improving spectrum utilization and enhancing resistance to multipath interference. However, in existing PLC protocols, OFDM-based PLC typically employs a single-user mode, meaning that all subcarriers on the channel are exclusively occupied by a single user at any given time. This mode has several drawbacks. First, different users have varying frequency selectivity; some subcarriers may experience deep fading for certain users, but the single-user mode still occupies all subcarriers, failing to dynamically allocate frequency resources based on user needs and channel quality, resulting in significant spectrum waste and limiting transmission rate increases. Second, different users have their own synchronization signals, transmitted at different times. To avoid interference between users, sufficient frame length must be reserved, causing a large amount of time-domain resources to be used for synchronization and waiting, reducing the efficiency of time-domain resource utilization. Furthermore, with the diversification of power line communication application scenarios and the increasing demand for data transmission, OFDM single-user mode is unable to meet the high-speed data communication needs, becoming a bottleneck for the development of power line communication towards high speed and high efficiency. Summary of the Invention

[0003] In view of this, the present application provides a base power line carrier multi-user communication method to solve at least one problem existing in the background art.

[0004] In a first aspect, this application provides a power line carrier multi-user communication method applied to a proxy node, the method comprising:

[0005] Based on the real-time power line channel measurement results, each leaf node is divided into multiple target groups, and frequency domain resources are allocated to each leaf node in each target group; where the power line measurement results refer to the channel measurement results between each leaf node and the proxy node.

[0006] Multi-user transmission request frames are periodically broadcast to enable each leaf node of the target group to start multi-user transmission mode; wherein, the payload data of each multi-user transmission request frame includes uplink task, identification information of a target group, feedback start time, feedback period, identification information, and allocated frequency domain resources of each leaf node of the target group.

[0007] Receive uplink data frames sent in parallel by each leaf node of the target group at the corresponding feedback start time and feedback period; wherein, each symbol in the uplink data frame of each leaf node is composed of subcarriers of the corresponding allocated frequency domain resources.

[0008] Secondly, embodiments of this application provide a power line carrier multi-user communication method applied to leaf nodes, the method comprising:

[0009] The leaf nodes receive and parse the multi-user transmission request frames sent by the proxy nodes; the payload data in the multi-user transmission request frames includes the uplink task, the identification information of the target group, the feedback start time, feedback period, identification information, and allocated frequency domain resources of each leaf node corresponding to the target group;

[0010] Determine whether the identification information matches the identification information in the multi-user transmission request frame. If they match, start the multi-user transmission mode and send the uplink data frame corresponding to the uplink task based on the feedback start time and feedback period in the multi-user transmission request frame. The uplink data frame corresponding to the leaf node is composed of subcarriers in the corresponding allocated frequency domain resources.

[0011] This application provides a power line carrier multi-user communication method. Based on power line channel measurement results, the method divides leaf nodes into multiple target groups and allocates frequency domain resources to each leaf node in each target group. Then, it periodically broadcasts multi-user transmission request frames to each target group and finally receives uplink data frames transmitted in parallel by each leaf node in each target group within the allocated frequency domain resources. This application, through frequency domain resource allocation, enables parallel data transmission by each leaf node. On the one hand, it reduces frame synchronization and frame waiting time, avoiding waste of time domain resources; on the other hand, frequency domain allocation based on channel measurement maximizes the utilization of spectrum resources, with leaf nodes within the same target group sharing the channel, thereby improving the transmission rate.

[0012] 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

[0013] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0014] Figure 1 This is a schematic diagram of the power line communication system topology provided in an embodiment of this application;

[0015] Figure 2A flowchart of a power line carrier multi-user communication method applied to a proxy node, provided in an embodiment of this application;

[0016] Figure 3 A flowchart illustrating a power line carrier multi-user communication method applied to leaf nodes, as provided in an embodiment of this application. Detailed Implementation

[0017] 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.

[0018] The core of Orthogonal Frequency Division Multiplexing (OFDM) modulation technology is to decompose a high-speed data stream into multiple orthogonal parallel low-speed subcarrier signals for transmission. In existing power line carrier communication protocols, power line communication is a single-user-to-single-user transmission mode based on OFDM. The single-user transmission mode cannot effectively utilize time-domain and frequency-domain resources, thus limiting the improvement of transmission rate.

[0019] In view of this, the present invention proposes a power line carrier multi-user communication method. This method groups leaf nodes based on real-time power line channel measurement results, and then broadcasts multi-user transmission request frames. This causes each leaf node in the target group to send uplink data frames composed of subcarriers of the corresponding allocated frequency domain resources, thereby enabling all leaf nodes to send uplink data frames simultaneously. This allows multiple users to send data to the proxy node at the same time. On the one hand, frequency domain resources are dynamically allocated based on channel measurement results, which can reduce frequency domain resource waste and improve transmission rate. On the other hand, each leaf node in the target group sends data frames corresponding to its allocated frequency domain resources, thereby reducing synchronization and idle waiting time and improving time domain resource utilization.

[0020] The power line carrier target data modulation method provided by the present invention will be described in detail below with reference to the accompanying drawings, through specific embodiments and application scenarios.

[0021] For HPLC systems, existing 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, transmitted signals are typically achieved through the sequential transmission of individual PPDU (Physical Protocol Data Unit) data frames. A PPDU frame typically contains a preamble, a frame control (FC) signal, and a payload (PL). The preamble, composed of multiple synchronization symbols, is used for frame synchronization and channel estimation. The FC signal describes basic frame information, such as the modulation mode of the data 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. It should be noted that the preamble and FC signals generally have fixed lengths, while the payload length can dynamically change based on protocol requirements or the actual communication environment.

[0022] Figure 1 This is a schematic diagram of the power line communication system topology provided in an embodiment of this application. Figure 1 As shown, the topology is a tree-like network structure. The nodes in the topology diagram mainly include a 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. It should be noted that in this embodiment, the leaf nodes refer to the next-level nodes of the corresponding proxy nodes. Taking proxy node PCO1 as an example, PCO1's leaf nodes include STA4, PCO2, PCO3, and STA5. In power line carrier communication, the number of leaf nodes under a single power node varies, typically ranging from 10 to 60.

[0023] With the development of smart grids, minute-level acquisition of power data is becoming increasingly important for refined power data analysis. Minute-level acquisition means collecting power-related data every minute (1 minute, 5 minutes, or 10 minutes), which can reflect the real-time operating status of the power system in a timely and accurate manner, providing crucial information for power operation analysis, fault prediction, and load regulation. In existing technologies, due to the large number of leaf nodes, the traditional single-user transmission mode cannot effectively utilize limited frequency domain resources. Simultaneously, a large amount of time domain resources are used for synchronization and waiting, resulting in ineffective utilization and failing to meet the requirements of minute-level data acquisition. For example, data may be collected every minute, but due to the large number of leaf nodes, the proxy node needs to synchronize the signal received from each leaf node, and sufficient frame length must be maintained for signal transmission between leaf nodes to avoid interference. Ultimately, this may result in all leaf nodes not completing transmission within one minute, thus failing to achieve minute-level data acquisition.

[0024] Figure 2 A flowchart illustrating a power line carrier multi-user communication method applied to a proxy node, as provided in an embodiment of this application. Figure 2 As shown, the method in this application embodiment includes:

[0025] S1. Based on the real-time power line channel measurement results, each leaf node is divided into multiple target groups, and frequency domain resources are allocated to each leaf node in each target group.

[0026] In this embodiment, the power line channel measurement result refers to the channel measurement result between each leaf node and the proxy node. The channel measurement result includes the signal-to-noise ratio (SNR) of all subcarrier groups within a preset frequency band. The preset frequency band is divided into multiple subcarrier groups, each containing an equal number of subcarriers. The SNR of a subcarrier group is the average SNR of the subcarriers within that group. For example, if the preset frequency band contains 512 subcarriers, and is divided into 16 subcarrier groups, each containing 32 subcarriers, then the channel measurement result for each leaf node is the SNR of the corresponding 16 subcarrier groups.

[0027] In this embodiment of the application, the leaf nodes are divided into multiple target groups based on real-time power line channel measurement results, including:

[0028] The average signal-to-noise ratio of the subcarrier group corresponding to each leaf node is calculated based on the real-time power line channel measurement results.

[0029] Based on the average signal-to-noise ratio of the subcarrier groups corresponding to each leaf node, each leaf node is divided into multiple target groups according to a preset grouping rule.

[0030] Specifically, each leaf node is divided into multiple target groups according to preset grouping rules, including:

[0031] The average signal-to-noise ratio of the subcarrier group of each leaf node is compared with the signal-to-noise ratio threshold of the modulation mode to determine the modulation mode matched by each leaf node.

[0032] Based on a preset number of nodes, leaf nodes corresponding to the same modulation mode are grouped into the same target group.

[0033] In this embodiment, the average signal-to-noise ratio (SNR) of the subcarrier group accurately reflects the average reliable transmission level of subcarriers within a preset frequency band under real-time channel conditions. Then, by comparing this SNR with the modulation mode threshold, the modulation mode matched to each leaf node can be determined. Grouping leaf nodes with the same modulation mode into the same target group ensures that nodes within the group use the same or similar transmission parameters during communication, thereby improving the overall reliability and efficiency of communication and facilitating subsequent allocation of frequency domain resources. Furthermore, arranging leaf nodes corresponding to the same modulation mode in order of the average SNR of the subcarrier group and grouping them sequentially according to the preset number of nodes further reduces the channel quality gap between leaf nodes. In existing technologies, the average SNR of the subcarrier group is generally sorted by size before grouping. However, this method does not consider the influence of the modulation mode. When leaf nodes within the same target group match different modulation modes, the nodes within the group cannot use unified transmission parameters due to modulation mode differences, which may lead to communication interruptions or resource waste due to parameter mismatch. It should be noted that the higher the modulation order of the modulation mode, the more bits can be transmitted per subcarrier, but the corresponding signal-to-noise ratio (SNR) threshold is also higher. The modulation modes in this application include Binary Phase Shift Keying (BPSK), Quadrature Phase Shift Keying (QPSK), 16-Quadrature Amplitude Modulation (16QAM), or 64-Quadrature Amplitude Modulation (16QAM). BPSK is suitable for low SNR, transmitting 1 bit per subcarrier, offering strong anti-interference capability but weak transmission capability; 16QAM is suitable for high SNR, transmitting 4 bits per subcarrier, offering weak anti-interference capability but strong transmission capability.

[0034] In this embodiment of the application, frequency domain allocation is performed on each leaf node of each target group, specifically including:

[0035] Frequency domain allocation is performed based on the signal-to-noise ratio of the subcarrier groups corresponding to each leaf node within the target group.

[0036] In this embodiment, the subcarrier groups assigned to each leaf node are different. Frequency domain allocation is performed based on the subcarrier group signal-to-noise ratio (SNR), allowing for dynamic allocation according to the real-time SNR. This enables timely adjustment of the subcarrier group configuration of each leaf node, maintaining good communication performance and enhancing the system's adaptability and robustness. For example, if a target group has 4 leaf nodes and 16 subcarrier groups, distributing the subcarrier groups evenly among the leaf nodes results in each leaf node having a fixed 4 subcarrier groups. The specific allocation can be performed in real-time based on the SNR of the subcarrier groups corresponding to each leaf node, ensuring that each leaf node fully utilizes the subcarrier groups with good channel quality. It should be noted that some subcarrier groups within the preset frequency band may remain idle during the allocation process; therefore, the total number of subcarrier groups allocated to each leaf node within the target group is less than or equal to the total number of subcarriers within the frequency band.

[0037] Furthermore, if the modulation scheme matched by each leaf node within a target group is BPSK or QPSK, and the modulation scheme corresponding to the target group is also BPSK or QPSK, then the subcarrier groups corresponding to each leaf node within the target group are spaced apart by at least one subcarrier group. This reduces inter-user interference caused by frequency offset between different leaf nodes and improves the communication reliability and stability when each leaf node transmits in parallel. If the modulation scheme matched by each leaf node is 16QAM or 64QAM, and the modulation scheme of the target group is BPSK or QPSK, then there is no space between the subcarrier groups of each leaf node to fully utilize frequency domain resources and improve the transmission rate. It should be noted that frequency offset refers to the sampling deviation between the leaf node and the proxy node. Since the deviations of each leaf node within the same target group are different, if there is no space, inter-symbol interference will occur between the leaf nodes when they transmit in parallel, thus affecting the overall performance. It is understandable that the modulation mode matched by each leaf node is 16QAM or 64QAM. However, due to the scarcity of frequency domain resources, the multi-leaf node + QPSK method still has an advantage in transmission rate compared to the few-leaf node + 16QAM method. Therefore, the multi-leaf node + QPSK mode can be adopted to make full use of frequency domain resources and improve the transmission rate.

[0038] In power line carrier communication, the frequency selectivity of different leaf nodes varies. This application's embodiments allocate frequency based on the signal-to-noise ratio of the subcarrier groups corresponding to each leaf node within the target group. This, combined with channel quality, allows for effective allocation, improving frequency utilization and enabling the transmission of more data within the same spectrum bandwidth, thus increasing the overall system throughput. In the real-time example of this application, each leaf node within the target group shares a preset frequency band range, allowing for parallel transmission in the time domain. This reduces the redundant synchronization and waiting time of each leaf node, improving the overall network transmission rate.

[0039] S2. Periodically broadcast multi-user transmission request frames to enable each leaf node of the target group to start multi-user transmission mode.

[0040] The multi-user transmission request frame (MPRFP) consists of individual PPDU frames, each including a preamble, frame control signal, and payload data. In this embodiment, the payload data of each MPRFP includes the uplink task, the identification information of a target group, the feedback start time of each leaf node in that target group, the feedback period, the identification information, and the allocated frequency domain resources. The MPRFP includes two scenarios: one where each request frame contains only the identification information of one target group, and another where each request frame includes the identification information of all target groups. In this embodiment, the MPRFP includes only the identification information of one target group each time. This allows for a shorter feedback period, enabling more timely acquisition of uplink data frames for the corresponding target group. Furthermore, the interval can be flexibly adjusted based on real-time changes in the target group's channel, ensuring communication quality. Simultaneously, when a leaf node in a target group needs to exit multi-user mode due to changes in the channel environment, or when a new leaf node needs to join multi-user mode, the proxy node can exit multi-user transmission mode more quickly and adjust the target group information promptly. It should be noted that when a multi-user transmission request frame includes only the identification information of a target user group, on the one hand, the amount of data carried by the request frame is small, and the proxy node can complete the transmission of the request frame faster; on the other hand, the number of leaf nodes is also smaller, and each leaf node can complete the transmission of uplink data frames faster. Therefore, the cycle duration can be set to be shorter. If the OFMA request frame includes the identification information of all target groups, then the amount of data in the request frame and the total time for the target groups to transmit uplink data frames must be considered, which will greatly increase the cycle duration and make it impossible to adjust it flexibly and dynamically.

[0041] As an optional implementation, the feedback cycles of all leaf nodes within the same target group are the same, and the feedback start time is determined based on the transmission distance between each leaf node and the proxy node, so that the proxy node can simultaneously receive the uplink data frames from each leaf node. Specifically, if the transmission distance between each leaf node and the proxy node is different, the data sent by each leaf node will arrive at the proxy node at different times, resulting in different delays. The multipath propagation caused by these delays will affect signal synchronization and other processing. In this embodiment, the delay between each node can be estimated based on the transmission distance between each leaf node and the proxy node. Then, the feedback start time of each leaf node is set according to the delay magnitude, i.e., the feedback start time for larger delays is earlier, and the feedback start time for smaller delays is later. This allows the uplink data frames sent by each leaf node to arrive at the proxy node simultaneously, reducing the impact of multipath propagation on transmission performance. It should be noted that the transmission distance between each leaf node and the proxy node can be measured by sending ranging commands, which will not be elaborated here.

[0042] In this embodiment of the application, after receiving the OFMDA transmission request frame, the leaf node parses it and searches for the leaf node's identification information in the parsing result. If a match is found, the corresponding target group identification information, allocated frequency domain resources, feedback start time and feedback period, etc. are read and recorded, and uplink data frames are sent at the corresponding resource allocation position and feedback time.

[0043] S3. Receive the uplink data frames sent in parallel by each leaf node of the target group at the corresponding feedback start time and feedback period.

[0044] In this system, each symbol in the uplink data frame transmitted in parallel by each leaf node consists of subcarriers within its allocated frequency domain resources; that is, each symbol is composed of subcarriers within its allocated subcarrier group. For example, if a leaf node is allocated subcarrier groups REG1 and REG2, then each OFDM symbol in that leaf node consists of subcarriers included in REG1 and REG2. This allows each leaf node to transmit data using various frequency bands. After receiving the data, the proxy node parses the frequency band information corresponding to each leaf node to obtain the data reported by each leaf node. Because leaf nodes within the same target group have different frequency domain resources, they can achieve parallel transmission. Each leaf node simultaneously transmits uplink data frames based on its allocated frequency domain resources, enabling different users to transmit data in the same time domain, improving time domain resource utilization, and reducing frame synchronization times and frame waiting time. Furthermore, each leaf node transmits signals based on its own frequency domain resources, which are allocated based on channel measurement results. This means multiple leaf nodes share the channel, maximizing spectrum resources and improving transmission efficiency. It should be noted that after receiving uplink data frames from leaf nodes of the same target group, the proxy node merges them. In subsequent processing, the corresponding frequency domain signals are separated to obtain the data transmitted by each leaf node. If a target group includes four leaf nodes, these four leaf nodes transmit uplink data frames in parallel using their respective frequency domain resources. For each PPDU frame, the proxy node only needs to perform synchronization once upon receipt, and then parses and separates the frequency domain data to obtain the data transmitted by each leaf node. However, in single-user transmission mode, the four leaf nodes transmit four times at different time periods. For each PPDU frame transmitted by each leaf node, synchronization is required four times, resulting in a significant waste of time domain resources.

[0045] As an optional specific implementation, after S3, it also includes:

[0046] Based on preset fallback rules, the proxy node exits multi-user transmission mode or sends an OFMDA stop frame to cause the corresponding leaf node to exit multi-user transmission mode.

[0047] Optional, preset rollback rules include:

[0048] If the proxy node completes the communication task with a certain leaf node or the proxy node does not receive an uplink data frame from a certain leaf node under preset conditions, the proxy node sends a first multi-user stop frame to cause the leaf node to exit the multi-user transmission mode.

[0049] Among them, if a proxy node does not receive an uplink data frame from a certain leaf node under preset conditions, it includes:

[0050] After sending a preset number of multi-user transmission request frames to the target group corresponding to the leaf node, the proxy node did not receive the uplink data frames from the leaf node.

[0051] In this embodiment, if the proxy node does not receive an uplink data frame from a leaf node of the corresponding target group after sending a multi-user transmission request frame, it indicates that the communication task of the target group has not been completed. At this time, the proxy node will repeatedly send multi-user request frames containing the corresponding target group identification information to request to receive data from the leaf node. If no feedback is received after exceeding a preset number of times, it indicates that the leaf node cannot provide normal feedback or the channel has deteriorated. Correspondingly, the proxy node sends a first multi-user stop frame to make the leaf node exit the multi-user transmission mode.

[0052] In this embodiment of the application, after the proxy node completes the communication task with a certain leaf node, that is, all the uplink data frames corresponding to the uplink task of the leaf node have been received by the proxy node, the proxy node sends the first multi-user stop frame before sending the next multi-user transmission request frame, so that the leaf node exits the multi-user transmission mode.

[0053] It should be noted that the signals sent by the proxy node are divided into broadcast signals and unicast signals. Broadcast signals simultaneously notify all leaf nodes corresponding to the target group through a single frame, realizing dynamic resource sharing and parallel feedback. Unicast signals require sending instructions to each leaf node separately, resulting in exclusive resource allocation and linearly increasing latency with the number of nodes. Broadcast signals can allocate time-frequency resources for multiple users at once, ensuring synchronous parallel transmission by all nodes, maximizing channel utilization and reducing feedback latency. Unicast signals, on the other hand, suffer from resource fragmentation and high latency due to multiple independent scheduling, failing to leverage the advantages of multi-user concurrency. In this embodiment, the multi-user transmission request frame is a broadcast signal, and the first multi-user stop frame is a unicast signal, thereby fully utilizing time-frequency resources and reducing feedback latency.

[0054] Optionally, the preset rollback rules also include:

[0055] When the conditions for reallocating communication resources are met, the agent node reallocates and broadcasts a second multi-user stop frame to cause all leaf nodes to exit multi-user transmission mode.

[0056] In this embodiment, meeting the conditions for reallocating communication resources refers to having idle frequency domain resources or idle time domain resources. Optionally, when adding a new leaf node or a new target group to idle frequency domain resources or idle time resources, the resources of existing leaf nodes or target groups cannot be modified to reduce the complexity of reallocation and speed up the processing. When the conditions for reallocating communication resources need to be met, the proxy node broadcasts a second user stop frame, thereby causing each leaf node corresponding to the target group to exit multi-user mode. Further, after broadcasting the second multi-user stop frame, the following steps are also included:

[0057] The proxy node rebroadcasts the multi-user transmission request frame to restart the multi-user transmission mode; wherein the duration between rebroadcasting the multi-user transmission request frame and broadcasting the second multi-user stop frame is greater than a first preset time threshold.

[0058] In this embodiment, when communication resource allocation is required, the current multi-user transmission mode is terminated by broadcasting a second multi-user stop frame. Then, after allocating communication resources, the proxy node rebroadcasts a multi-user transmission request frame to restart the multi-user transmission mode. To ensure that all leaf nodes exit the previous round of multi-user transmission mode and avoid conflicts, a preset time threshold must be exceeded between sending the second multi-user stop frame and restarting the multi-user mode. The preset time threshold is generally greater than or equal to the duration corresponding to the feedback period, and the specific value can be determined according to the actual communication situation.

[0059] Optionally, the preset rollback rules also include:

[0060] If the proxy node does not receive uplink data frames from each of the current leaf nodes within a preset time threshold, the proxy node will stop sending multi-user transmission request frames to exit the multi-user transmission mode.

[0061] Specifically, if the proxy node has established a multi-user transmission mode with each leaf node, and the proxy node does not receive a response for a long time after sending a multi-user transmission request frame, exceeding the preset time threshold, it indicates that environmental changes have caused the frequency band where each leaf node is located to deteriorate. At this time, the proxy node stops sending multi-user transmission request frames to exit the multi-user transmission mode and return to normal frequency band communication, thereby avoiding communication interruption.

[0062] This application provides a power line carrier multi-user communication method. Based on power line channel measurement results, the method divides leaf nodes into multiple target groups and allocates frequency domain resources to each leaf node in each target group. Then, it periodically broadcasts multi-user transmission request frames to each target group and finally receives uplink data frames transmitted in parallel by each leaf node in each target group within the allocated frequency domain resources. This application, through frequency domain resource allocation, enables parallel data transmission by each leaf node. On the one hand, it reduces frame synchronization and frame waiting time, avoiding waste of time domain resources; on the other hand, frequency domain allocation based on channel measurement maximizes the utilization of spectrum resources, with leaf nodes within the same target group sharing the channel, thereby improving the transmission rate.

[0063] Figure 3 A flowchart illustrating a power line carrier multi-user communication method applied to leaf nodes, as provided in an embodiment of this application. Figure 3 As shown, the method in this application embodiment includes:

[0064] S100, the leaf node receives and parses the multi-user transmission request frame sent by the proxy node.

[0065] The payload data in the multi-user transmission request frame includes the uplink task, the identification information of the target group, the feedback start time, feedback period, identification information, and allocated frequency domain resources of each leaf node corresponding to the target group.

[0066] S200. Determine whether the identification information matches the identification information in the multi-user request frame. If they match, start the multi-user transmission mode and send the uplink data frame corresponding to the uplink task based on the feedback start time and feedback period in the multi-user transmission request frame.

[0067] The uplink data frames corresponding to the leaf nodes are composed of subcarriers in the corresponding allocated frequency domain resources. That is, each symbol in the uplink data frame is composed of the corresponding allocated subcarriers, so that it can share the channel with other leaf nodes in the same target group and send data in parallel.

[0068] As an optional specific implementation, sending uplink data frames based on the feedback start time and feedback period corresponding to the multi-user transmission request frame includes:

[0069] If the listening channel of a leaf node is occupied at the corresponding feedback start time, it will send an uplink data frame at the next feedback time based on the corresponding feedback period.

[0070] If a leaf node listens for an idle channel at the corresponding feedback start time, it will send an uplink data frame at the corresponding feedback start time.

[0071] Specifically, the leaf nodes listen to the channel. If it is occupied, they retransmit after one feedback cycle from the feedback start time. If it is still occupied, they retransmit after another feedback cycle until the channel is idle. Here, the next feedback time refers to the time when the channel is idle, based on the feedback cycle. If the channel is idle at the feedback start time, an uplink data frame is sent.

[0072] As an optional specific implementation, before the leaf node sends the uplink data frame, it also includes:

[0073] The number of symbols in the payload data is determined based on the uplink task and the allocated frequency domain resources. If the number of symbols in the payload data is greater than the preset number of symbols, pilot symbols are configured in the payload data symbols according to the preset interval.

[0074] Specifically, if the number of payload data symbols is less than the preset number of symbols, it indicates that less information is being transmitted. In this case, the residual frequency offset has little impact on performance and can be ignored. The corresponding receiver does not need to perform frequency offset tracking through pilots. If the number of payload data symbols is greater than the preset number of symbols, it indicates that more information is being transmitted. In this case, by configuring pilot symbols in the payload data symbols at preset intervals, the corresponding receiver can perform frequency offset tracking based on the pilot symbols to correct the impact of frequency offset. It should be noted that the presence or absence of pilots and the information of pilot symbols can be placed in the frame control information. Pilot symbols are periodic known signal sequences, and proxy nodes can perform frequency offset correction based on pilot symbols. In multi-user communication mode, the parallel transmission of data by multiple leaf nodes can lead to mutual frequency interference between nodes. When the data volume is large, frequency offset has a significant impact on performance. In this embodiment, pilot symbols are configured in the payload data symbols at preset intervals, which can effectively perform frequency offset tracking and correction, avoid the adverse effects of frequency offset, and ensure the reliability and accuracy of data transmission.

[0075] As an optional specific implementation method, the method of this application embodiment further includes:

[0076] If a leaf node receives the first multi-user stop frame sent by the proxy node, it replies with an acknowledgment frame to the proxy node to exit the multi-user transmission mode.

[0077] As an optional specific implementation method, the method of this application embodiment further includes:

[0078] If a leaf node receives a second multi-user stop frame broadcast by the proxy node, it exits the multi-user transmission mode.

[0079] It should be understood that, although Figures 2-3The 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 herein, there is no strict order in which these steps are executed, and they can be performed in other orders. Figures 2-3 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.

[0080] It should be noted that the power line carrier multi-user communication method embodiments provided in this application for agent nodes and power line carrier multi-user communication method embodiments for leaf nodes belong to the same concept; the technical features in the technical solutions described in each embodiment can be arbitrarily combined without conflict.

[0081] 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 multi-user communication method applied to a proxy node, characterized in that, The method comprises: dividing each leaf node into a plurality of target groups based on real-time power line channel measurement results, and performing frequency domain resource allocation for each leaf node in each target group; wherein the power line measurement results refer to channel measurement results between each leaf node and the proxy node; periodically broadcasting a multi-user transmission request frame to enable each leaf node in a target group to start a multi-user transmission mode; wherein the payload data of the multi-user transmission request frame transmitted each time includes an uplink task, identification information of a target group, feedback start time, feedback period, identification information, and allocated frequency domain resources of each leaf node in the target group; receiving uplink data frames sent in parallel by each leaf node in the target group at the corresponding feedback start time and feedback period; wherein each symbol in the uplink data frame of each leaf node is composed of a subcarrier corresponding to the allocated frequency domain resource; based on a preset back-off rule, the proxy node exits the multi-user transmission mode or the proxy node sends an OFMDA stop frame to enable the corresponding leaf node to exit the multi-user transmission mode; wherein dividing each leaf node into a plurality of target groups based on real-time power line channel measurement results comprises: calculating the average signal-to-noise ratio of the subcarrier group corresponding to each leaf node based on real-time power line channel measurement results; comparing the average signal-to-noise ratio of the subcarrier group of each leaf node with the signal-to-noise ratio threshold value of the modulation mode to determine the matched modulation mode of each leaf node; based on a preset number of nodes, the leaf nodes corresponding to the same modulation mode are divided into the same target group.

2. The power line carrier multi-user communication method of claim 1, wherein, The preset back-off rule comprises: if the proxy node completes the communication task with a certain leaf node or the proxy node does not receive the uplink data frame of a certain leaf node under a preset condition, the proxy node sends a first multi-user stop frame to enable the leaf node to exit the multi-user transmission mode.

3. The power line carrier multi-user communication method of claim 2, wherein, the proxy node does not receive the uplink data frame of a certain leaf node under a preset condition, comprising: after sending a preset number of multi-user transmission request frames to the target group corresponding to the leaf node, the proxy node does not receive the uplink data frame of the leaf node.

4. The power line carrier multi-user communication method of claim 1, wherein, The preset back-off rule comprises: when the re-allocation of communication resources is met, the proxy node re-allocates and broadcasts a second multi-user stop frame to enable all leaf nodes to exit the multi-user transmission mode.

5. The power line carrier multi-user communication method of claim 4, wherein, after broadcasting the second multi-user stop frame, further comprising: the proxy node re-broadcasts a multi-user transmission request frame to restart the multi-user transmission mode; wherein the time length between re-broadcasting the multi-user transmission request frame and broadcasting the second multi-user stop frame is greater than a preset time threshold.

6. The power line carrier multi-user communication method of claim 1, wherein, The preset back-off rule comprises: if the proxy node does not receive the uplink data frame of the current leaf node within a preset time threshold, the proxy node stops sending the multi-user transmission request frame to exit the multi-user transmission mode.

7. A power line carrier multi-user communication method applied to a leaf node, characterized in that, The method comprises: The leaf node receives and analyzes the multi-user transmission request frame sent by the proxy node; wherein the payload data in the multi-user transmission request frame includes uplink tasks, identification information of the target group, feedback start time, feedback period, identification information, and allocated frequency domain resources of each leaf node corresponding to the target group; If the identification information matches the identification information in the multi-user transmission request frame, the multi-user transmission mode is started, and the uplink data frame corresponding to the uplink task is sent based on the corresponding feedback start time and feedback period in the multi-user transmission request frame; wherein the uplink data frame corresponding to the leaf node is composed of subcarriers in the corresponding allocated frequency domain resources; The proxy node divides the leaf nodes into multiple target groups based on real-time power line channel measurement results, and allocates frequency domain resources to each leaf node in each target group; specifically including: Based on the real-time power line channel measurement results, the average signal-to-noise ratio of the subcarrier group corresponding to each leaf node is calculated; The average signal-to-noise ratio of the subcarrier group of each leaf node is compared with the signal-to-noise ratio threshold value of the modulation mode to determine the matched modulation mode of each leaf node; Based on the preset number of nodes, the leaf nodes corresponding to the same modulation mode are divided into the same target group.

8. The power line carrier multi-user communication method of claim 7, wherein, Sending the uplink data frame based on the corresponding feedback start time and feedback period in the multi-user transmission request frame includes: If the channel is occupied when the leaf node listens to the channel at the corresponding feedback start time, the uplink data frame is sent at the next feedback time based on the corresponding feedback period; If the channel is idle when the leaf node listens to the channel at the corresponding feedback start time, the uplink data frame is sent at the corresponding feedback start time; The leaf node listens to the channel based on the corresponding allocated frequency domain resources.

9. The power line carrier multi-user communication method of claim 7, wherein, The method further includes: If the leaf node receives the first multi-user stop frame sent by the proxy node, the proxy node is replied with an acknowledgement information frame to exit the multi-user transmission mode.

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