HPLC communication mode selection method based on OFDM system

Abstract

The application discloses a HPLC communication mode selection method based on an OFDM system and belongs to the technical field of communication. The HPLC communication mode selection method based on the OFDM system comprises the following steps: a first signal frame is transmitted in a first diversity copy mode, so that the receiving end decodes and processes the first signal frame; if no acknowledgement frame used for indicating decoding success is acquired, a second diversity copy mode with a transmission rate level lower than the first diversity copy mode is selected, a second signal frame is transmitted in the second diversity copy mode; if no corresponding acknowledgement frame is still acquired, the steps of selecting and transmitting a next signal frame are repeatedly executed until the corresponding acknowledgement frame is acquired; a target diversity copy mode is determined according to the selected diversity copy mode, and data is transmitted in the target diversity copy mode. The application realizes high-efficiency and high-reliability data transmission.

Description

Technical Field

[0001] This invention belongs to the field of communication technology, and in particular relates to an HPLC communication mode selection method based on an OFDM system. Background Technology

[0002] With the rapid development of smart grid and Internet of Things technologies, high-speed power line communication (HPLC), as an important branch of broadband power line carrier technology, has been widely used due to its advantages such as large bandwidth, high transmission rate, and strong anti-interference ability.

[0003] In HPLC communication systems, the power line channel environment is complex and variable, exhibiting problems such as noise interference and signal attenuation. To address this issue, related technologies typically employ diversity copying techniques, pre-setting multiple diversity copying modes within the system. Different modes correspond to different modulation schemes and copy counts, resulting in varying transmission rates and signal-to-noise ratio thresholds. In practical applications, the signal transmitter progressively attempts from multiple diversity copying modes to determine the target mode suitable for the current channel conditions, aiming to maximize transmission efficiency while ensuring communication reliability.

[0004] However, when channel conditions are poor, the signal transmitter in the above method needs to try multiple modes to find a suitable target mode, resulting in low mode selection efficiency. In addition, the received results are independent of each other, which makes it impossible for the signal transmitter to effectively refer to the previously received information. The selected diversity copy mode is difficult to adaptively match the current channel conditions, thus making it difficult to achieve high-efficiency and high-reliability data transmission. Summary of the Invention

[0005] This invention aims to address at least one of the technical problems existing in the prior art. To this end, this invention proposes an HPLC communication mode selection method based on an OFDM system to achieve high-efficiency and high-reliability data transmission.

[0006] In a first aspect, the present invention provides an HPLC communication mode selection method based on an OFDM system, applied at the transmitting end, wherein the transmitting end is configured with multiple diversity copy modes, each diversity copy mode corresponding to a different transmission rate level; the method includes: The first signal frame is sent in the first diversity copy mode so that the receiving end can decode the first signal frame; If no confirmation frame indicating successful decoding is obtained, a second diversity copy mode with a transmission rate level lower than the first diversity copy mode is selected, and the second signal frame is sent in the second diversity copy mode. If the corresponding acknowledgment frame is still not obtained, repeat the steps of selecting and sending the next signal frame until the corresponding acknowledgment frame is obtained. The target diversity copy mode is determined based on the selected diversity copy mode, and data is transmitted in the target diversity copy mode.

[0007] According to one embodiment of the present invention, the second diversity copy mode is separated from the first diversity copy mode by at least one rate level.

[0008] According to one embodiment of the present invention, the step of repeatedly selecting and sending the next signal frame specifically includes: obtaining equivalent diversity parameters based on the signal-to-noise ratio parameters corresponding to each of the selected diversity copy modes; obtaining an equivalent combined signal-to-noise ratio based on the ratio of the equivalent diversity parameters to the reference signal-to-noise ratio; selecting the next diversity copy mode whose transmission rate level is lower than the rate level corresponding to the equivalent combined signal-to-noise ratio, and sending the next signal frame in the next diversity copy mode.

[0009] According to one embodiment of the present invention, determining a target diversity copy mode based on the selected diversity copy mode specifically includes: obtaining equivalent diversity parameters based on the signal-to-noise ratio parameters corresponding to each of the selected diversity copy modes; and selecting a diversity copy mode that matches the equivalent diversity parameters as the target diversity copy mode.

[0010] According to one embodiment of the present invention, the signal-to-noise ratio (SNR) parameter includes a copy number parameter and a modulation mode coefficient. Based on the SNR parameters corresponding to each of the selected diversity copy modes, an equivalent diversity parameter is obtained, specifically including: obtaining the copy number parameter and modulation mode coefficient corresponding to each of the selected diversity copy modes; calculating the ratio of the copy number parameter to the modulation mode coefficient for each selected diversity copy mode, and summing the ratios to obtain the equivalent diversity parameter.

[0011] According to one embodiment of the present invention, selecting a diversity copy mode that matches the equivalent diversity parameters as the target diversity copy mode specifically includes: if BPSK modulation is used, selecting a diversity copy mode with a copy number equal to the equivalent diversity parameters as the target diversity copy mode; if QPSK modulation is used, selecting a diversity copy mode with a copy number equal to twice the equivalent diversity parameters as the target diversity copy mode; if 16QAM modulation is used, selecting a diversity copy mode with a copy number equal to ten times the equivalent diversity parameters as the target diversity copy mode.

[0012] According to one embodiment of the present invention, the method further includes: if no acknowledgment frame is received after repeatedly performing the step of selecting and sending the next signal frame a preset number of times, the diversity copy mode of the lowest transmission rate level is used as the target diversity copy mode.

[0013] Secondly, this invention provides an HPLC communication mode selection method based on an OFDM system, applied at the receiving end, the method comprising: When the first signal frame is received from the sender in the first diversity copy mode, the first LLR value corresponding to the first signal frame is obtained. The first signal frame is decoded based on the first LLR value; If decoding fails, a negative frame is sent back to the sender, so that after receiving the negative frame, the sender selects a second diversity copy mode with a transmission rate level lower than the first diversity copy mode to send a second signal frame. Receive the second signal frame, obtain the second LLR value corresponding to the second signal frame, and merge the second LLR value with the first LLR value to obtain the merged LLR value; The second signal frame is decoded based on the merged LLR value; If decoding is successful, an acknowledgment frame is sent back to the sender, so that the sender can determine the target diversity copy mode based on the selected diversity copy mode and transmit data in the target diversity copy mode. If decoding still fails, continue to send a negative frame to the sender to trigger the sender to repeat the step of selecting and sending the next signal frame until decoding is successful.

[0014] According to one embodiment of the present invention, merging the second LLR value with the first LLR value to obtain a merged LLR value specifically includes: directly adding the second LLR value and the first LLR value according to their corresponding bit positions to obtain the merged LLR value.

[0015] According to one embodiment of the present invention, the method further includes: performing soft-decision decoding on the acquired LLR value to obtain a decoded bit sequence; performing cyclic redundancy check on the bit sequence, and determining that decoding is successful if the check passes, and determining that decoding fails if the check fails.

[0016] Thirdly, the present invention provides an HPLC communication mode selection system based on an OFDM system, the system comprising: The transmitting end is used to implement the HPLC communication mode selection method based on the OFDM system as described in the first aspect above. The receiving end is used to implement the HPLC communication mode selection method based on the OFDM system as described in the second aspect above.

[0017] Fourthly, the present invention provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the HPLC communication mode selection method based on the OFDM system as described in the first or second aspect above.

[0018] Fifthly, the present invention provides a non-transitory computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the HPLC communication mode selection method based on an OFDM system as described in the first or second aspect above.

[0019] In a sixth aspect, the present invention provides a chip including a processor and a communication interface, the communication interface being coupled to the processor, the processor being used to run programs or instructions to implement the HPLC communication mode selection method based on the OFDM system as described in the first or second aspect above.

[0020] In a seventh aspect, the present invention provides a computer program product, including a computer program that, when executed by a processor, implements the HPLC communication mode selection method based on an OFDM system as described in the first or second aspect above.

[0021] The above-described one or more technical solutions in the embodiments of the present invention have at least one of the following technical effects: By sending a first signal frame in the first diversity copy mode, the receiving end decodes the first signal frame. Initially, data is attempted to be transmitted to the receiving end at a higher transmission rate to avoid unnecessarily reducing the transmission rate when channel conditions permit. Subsequently, if no acknowledgment frame indicating successful decoding is obtained, it indicates that a second diversity copy mode with a lower transmission rate should be selected under the current channel conditions. The second signal frame is then sent in the second diversity copy mode, thus reducing the probability of retransmission failure due to insufficient channel conditions by lowering the transmission rate to adapt to the current channel quality. If no acknowledgment frame is obtained after this, the selection process is repeated. The process involves sending the next signal frame until a corresponding acknowledgment frame is obtained. This ensures reliable data transmission while maintaining a relatively high transmission rate through iterative rate reduction. Finally, a target diversity copy mode is determined based on the selected diversity copy mode, and data is transmitted using this target diversity copy mode. By comprehensively deciding on the diversity copy mode based on information from multiple selected diversity copy modes, the channel quality estimation bias and insufficient or excessive rate redundancy caused by relying solely on a single diversity copy mode when decoding is successful are avoided. This allows the determined target diversity copy mode to adaptively match the current channel conditions, achieving high-efficiency and high-reliability data transmission.

[0022] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0023] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a parameter diagram corresponding to various diversity copy modes provided in some embodiments of the present invention; Figure 2 This is a flowchart illustrating the HPLC communication mode selection method based on an OFDM system provided in some embodiments of the present invention; Figure 3 This is a flowchart illustrating the HPLC communication mode selection method based on an OFDM system provided in other embodiments of the present invention; Figure 4 This is a schematic diagram of the structure of an electronic device provided in some embodiments of the present invention. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0025] The terms "first," "second," etc., used in the specification and claims of this invention are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0026] In the field of communications, HPLC technology employs multi-carrier modulation techniques such as Orthogonal Frequency Division Multiplexing (OFDM) to transmit data by modulating it onto multiple orthogonal subcarriers. It is widely used due to its advantages such as high spectral efficiency and strong resistance to multipath interference.

[0027] In HPLC communication systems, the power line channel environment between the signal transmitter and receiver is complex and variable, exhibiting problems such as noise interference, signal attenuation, and frequency-selective fading, leading to unstable communication quality. To address these channel issues, related technologies typically employ diversity copying, which involves repeatedly transmitting the same data bit on different subcarriers or at different times, and then performing diversity merging at the receiver to improve data transmission reliability and anti-interference capabilities.

[0028] In HPLC communication systems employing diversity copy technology, the system has multiple preset Transmission Mode Indexes (TMIs). Each TMI corresponds to a set of modulation schemes and copy numbers. Different TMIs can have different transmission rates and signal-to-noise ratio (SNR) thresholds. For example, the diversity copy modes can be TMI1 to TMI9, with the corresponding transmission rates and SNR thresholds decreasing sequentially.

[0029] In related technologies, the sending end or node needs to determine the target mode suitable for the current channel conditions from multiple diversity copy modes by traversing them. Specifically, the sending end or node first sends a Start of Frame (SOF) frame using a diversity copy mode with a higher transmission rate (such as TMI1). The receiving end or node receives and parses the SOF frame. If the sending end or node does not receive an acknowledgment (ACK) frame from the receiving end or node indicating that the parsing was successful, it then continues to send SOF frames using the second-highest transmission rate diversity copy mode (such as TMI2), and so on, gradually decreasing the transmission rate until a correct ACK frame is received from the receiving end or node. At this point, the diversity copy mode used is determined as the target mode, and the actual data is transmitted using this target mode. If a parsing fails, the receiving end or node can send a negative acknowledgment (NACK) frame back to the sending node.

[0030] However, the above scheme has the following problems in the method of selecting diversity copy mode: When the channel conditions are poor, for the transmitter, it needs to try multiple diversity copy modes step by step to find a suitable target diversity copy mode. The number of attempts is large, the time consumption is long, and the selection efficiency is low. For the receiver, the reception results of each attempt are independent of each other, and it is difficult for subsequent attempts to refer to the previous reception information. The diversity copy mode selected in the end is based on a single basis, and it is difficult to adaptively match the current channel conditions.

[0031] In view of this, embodiments of the present invention provide an HPLC communication mode selection method based on an OFDM system, which aims to solve the problem of low mode selection efficiency caused by traversing diversity copy modes step by step. By selecting a lower rate level diversity copy mode step by step or skipping levels when no confirmation feedback is received, and comprehensively determining the target diversity copy mode based on the diversity copies obtained from multiple attempts, high-efficiency and high-reliability data transmission is achieved.

[0032] The HPLC communication mode selection method based on the OFDM system provided in this invention will be described in detail below with reference to the accompanying drawings and through specific embodiments and application scenarios.

[0033] The HPLC communication mode selection method based on an OFDM system provided by this invention can be applied to an OFDM-based HPLC communication mode selection system. The OFDM-based HPLC communication mode selection system includes a transmitter and a receiver, which can communicate with each other via power lines or similar means.

[0034] Furthermore, the transmitting and receiving ends can be electronic devices, such as power line communication terminals, concentrator devices, smart meters, communication nodes, communication module embedded devices, or communication test terminals. Alternatively, the electronic devices can also be devices with computing capabilities or intelligent robots to perform the steps of transmitting signal frames, decoding, selecting diversity copy mode, and receiving signal frames in this invention.

[0035] The present invention provides an HPLC communication mode selection method based on an OFDM system. The execution subject of this method can be a transmitting end, or a functional module or functional entity in the transmitting end that can implement the method.

[0036] The following describes the HPLC communication mode selection method based on the OFDM system provided in this embodiment of the invention, taking the sending end as the executing entity as an example.

[0037] In this embodiment of the invention, the transmitting end is configured with multiple diversity copy modes. The transmitting end sends a signal frame to the receiving end using one of the multiple diversity copy modes and receives a feedback frame from the receiving end. For example, the feedback frame includes, but is not limited to, an acknowledgment frame indicating successful decoding and a negative acknowledgment frame indicating decoding failure. The transmitting end can determine whether to switch or adjust the diversity copy mode based on the feedback frame.

[0038] Diversity copy mode refers to the transmission mode configuration used to determine the modulation scheme and number of copies of the signal frame. In feasible implementations, the transmitting end can determine the appropriate diversity copy mode by setting the signal-to-noise ratio (SNR) threshold corresponding to different diversity copy modes, and then comparing the current channel quality with the SNR threshold. Figure 1This is a schematic diagram of parameters corresponding to various diversity copy modes provided in some embodiments of the present invention. For example... Figure 1 As shown, there are eight diversity copy modes, from TM1 to TM8, each corresponding to a different modulation scheme, number of copies, and signal-to-noise ratio (SNR) threshold. Specifically, TM1 uses QPSK (Quadrature Phase Shift Keying) modulation with 2 copies; TM2 uses QPSK modulation with 4 copies; TM3 uses QPSK modulation with 7 copies; TM4 uses QPSK modulation with 11 copies; TM5 uses BPSK (Binary Phase Shift Keying) modulation with 2 copies; TM6 uses BPSK modulation with 4 copies; TM7 uses BPSK modulation with 7 copies; and TM8 uses BPSK modulation with 11 copies. Each diversity copy mode has a corresponding SNR threshold, ranging from D1 to D7. The signal-to-noise ratio (SNR) thresholds for both TM2 and TM5 are D2. This is because TM2 uses QPSK modulation (2 bits per symbol) combined with 4 diversity copies, resulting in an equivalent number of bits transmitted per symbol of 0.5 bits / symbol; TM5 uses BPSK modulation (1 bit per symbol) combined with 2 copies, also resulting in an equivalent number of bits transmitted per symbol of 0.5 bits / symbol. Since their equivalent transmission rates are the same, the minimum SNR thresholds required to achieve the same decoding performance are also the same. In other words, in some implementations, the SNR threshold corresponding to the diversity copy mode is derived from the ratio of the modulation scheme (i.e., the number of bits per symbol) to the number of copies.

[0039] The copy count refers to the number of times the same bit of data is repeatedly transmitted in a diversity copy mode, characterizing the diversity repetition of this mode in the time dimension. The transmitting end repeatedly transmits the same bit of data multiple times, and the receiving end performs diversity combining on the received signals to enhance noise immunity and improve decoding success rate. In some implementations, the more copies, the higher the diversity gain obtained by the receiving end; correspondingly, the longer the transmission time required to carry the same amount of data, and the lower the transmission rate. That is, the copy count and transmission rate are negatively correlated; the more copies, the lower the transmission rate; the fewer copies, the higher the transmission rate.

[0040] In some implementations, as the signal-to-noise ratio (SNR) threshold decreases sequentially, the transmission rate level corresponding to the diversity copy mode also decreases sequentially. It is easy to understand that the transmission rate level refers to the relative ranking of data transmission rates corresponding to the diversity copy mode; the higher the transmission rate, the higher the corresponding transmission rate level; and vice versa. In other words, the SNR threshold and the transmission rate level are positively correlated; that is, the higher the transmission rate level, the higher the minimum SNR required for correct demodulation.

[0041] Figure 2 This is a flowchart illustrating the HPLC communication mode selection method based on an OFDM system provided in some embodiments of the present invention. For example... Figure 2 As shown, the HPLC communication mode selection method based on the OFDM system includes steps 210 to 240.

[0042] Step 210: Send the first signal frame in the first diversity copy mode so that the receiving end can decode the first signal frame.

[0043] The first diversity copy mode refers to the diversity copy mode that is selected first among multiple diversity copy modes for transmitting signal frames. For example, the first diversity copy mode may be the diversity copy mode with the highest transmission rate level among multiple diversity copy modes (such as TM1).

[0044] Furthermore, the signal frame sent by the transmitting end to the receiving end in the first diversity copy mode is referred to as the first signal frame. In feasible implementations, the first signal frame is used to carry data to confirm the diversity copy mode, so that the receiving end can perform decoding processing based on the first signal frame. For example, the first signal frame may be, for example, an SOF frame, a beacon frame, or a payload data frame.

[0045] Decoding refers to the process by which the receiving end demodulates, divides, merges, decodes, and verifies the received signal frame in order to obtain the data carried by the signal frame.

[0046] It should be noted that during the communication mode selection phase, the signal frame carries control information or a known sequence used to confirm the diversity copy mode, rather than informal transmission service data. In other words, the signal frame is used for mode probing and confirmation during the communication mode selection phase.

[0047] The transmitting end first acquires the data used to confirm the diversity copy mode, and modulates and performs diversity copy processing on the data according to the modulation method and number of copies corresponding to the first diversity copy mode to generate the first signal frame, and sends it to the receiving end so that the receiving end can decode the first signal frame after receiving it.

[0048] For example, if the first diversity copy mode is TM1 (QPSK modulation, 2-time diversity copy), the transmitting end modulates the data used to confirm the diversity copy mode according to the QPSK modulation method, performs 2-time diversity copy on the modulated data, generates the first signal frame and sends it.

[0049] In some implementations, the first diversity copy mode can be the diversity copy mode with the highest transmission rate among multiple diversity copy modes, so as to transmit data with the highest efficiency when channel conditions permit.

[0050] In other implementations, the first diversity copy mode may also be the second highest transmission rate diversity copy mode among multiple diversity copy modes, thereby appropriately reducing the number of attempts to switch diversity copy modes while transmitting data with high efficiency.

[0051] In some other implementations, the first diversity copy mode can also be determined based on historical communication records or channel quality estimation results. For example, if the target diversity copy mode determined in the previous communication was TM3, then the first diversity copy mode for this communication can be selected as TM3.

[0052] Step 220: If no confirmation frame indicating successful decoding is obtained, select a second diversity copy mode with a transmission rate level lower than the first diversity copy mode, and send the second signal frame in the second diversity copy mode.

[0053] An acknowledgment frame is a feedback frame used to indicate that the receiving end has successfully decoded the data. For example, an acknowledgment frame can be one or more of the following: an ACK frame, feedback information, etc.

[0054] The second diversity copy mode refers to any diversity copy mode among multiple diversity copy modes whose transmission rate level is lower than that of the first diversity copy mode. In other words, the second diversity copy mode is a different diversity copy mode from the first diversity copy mode, and the transmission rate level corresponding to the second diversity copy mode is lower than that corresponding to the first diversity copy mode.

[0055] The signal frame sent by the transmitting end in the second diversity copy mode is called the second signal frame.

[0056] If the sending end does not receive an acknowledgment frame after sending the first signal frame, it selects the second diversity copy mode, which has a lower transmission rate level than the first diversity copy mode, as the diversity copy mode for transmitting control information used to confirm the diversity copy mode, and sends the second signal frame in the second diversity copy mode.

[0057] In some implementations, the sending end not receiving an acknowledgment frame may be due to receiving a negative acknowledgment frame (e.g., NACK) from the receiving end. In other implementations, the sending end not receiving an acknowledgment frame may also be due to not receiving any feedback frame from the receiving end within a preset time (i.e., timeout).

[0058] In a feasible implementation, the transmitting end selects a second diversity copy mode with a transmission rate level lower than the first diversity copy mode. For example, it can select a diversity copy mode with the next lower rate level adjacent to the first diversity copy mode from multiple diversity copy modes as the second diversity copy mode. In other words, if the first diversity copy mode is TM1, then the second diversity copy mode is TM2; if the first diversity copy mode is TM2, then the second diversity copy mode is TM3, and so on.

[0059] In other feasible implementations, the transmitting end selects a second diversity copy mode with a transmission rate level lower than the first diversity copy mode. For example, it can also select a diversity copy mode that is at least one rate level lower than the first diversity copy mode from multiple diversity copy modes as the second diversity copy mode. For example, if the first diversity copy mode is TM1, the second diversity copy mode can be directly selected as TM4 or TM6, skipping the low transmission rate level with a larger step size, thereby reducing the number of probes.

[0060] In some other feasible implementations, the transmitting end selects a second diversity copy mode with a transmission rate level lower than that of the first diversity copy mode. For example, the second diversity copy mode can also be determined based on relevant parameters of the first diversity copy mode (such as modulation method, signal-to-noise ratio threshold, number of copies, etc.).

[0061] Through the above steps, when the sending end receives a negative acknowledgment frame from the receiving end, it determines that the receiving end cannot successfully decode using the current diversity copy mode. Therefore, it enhances the signal noise immunity by reducing the transmission rate level, thereby improving the decoding success rate of the receiving end.

[0062] Step 230: If the corresponding acknowledgment frame is still not obtained, repeat the step of selecting and sending the next signal frame until the corresponding acknowledgment frame is obtained.

[0063] Here, the next signal frame refers to the subsequent signal frame sent by the sending end in a newly selected diversity copy mode after failing to obtain an acknowledgment frame. For example, if the current signal frame has been sent up to the nth signal frame (n≥2) and an acknowledgment frame has still not been obtained, then the next signal frame is the (n+1)th signal frame.

[0064] If the transmitter fails to receive an acknowledgment frame after sending the second signal frame, it repeats the step of "selecting a diversity copy mode with a lower transmission rate and sending the signal frame in that mode" until an acknowledgment frame is received. After each failure, the transmitter further selects a diversity copy mode with an even lower transmission rate, thereby enhancing the signal's noise immunity with stronger redundancy coding and a lower modulation order, until the receiver successfully decodes and returns an acknowledgment frame. In other words, since each failed attempt means that the current channel conditions cannot support the current transmission rate level of the diversity copy mode, a diversity copy mode with a lower transmission rate needs to be selected to adapt to the current channel conditions.

[0065] In this context, "until the corresponding acknowledgment frame is obtained" means that the iteration process terminates and no further signal frames are sent after the receiving end successfully decodes a certain signal frame (let's say the Mth signal frame) and returns an acknowledgment frame. This acknowledgment frame is the acknowledgment frame corresponding to the Mth signal frame.

[0066] In some implementations, the sending end repeatedly performs the step of selecting and sending the next signal frame. For example, it may select the next diversity copy mode with a transmission rate level lower than the previously selected diversity copy mode each time. For example, TM1, TM2, TM3 are selected sequentially, i.e., in a step-down manner.

[0067] In other implementations, the transmitting end repeatedly performs the step of selecting and transmitting the next signal frame. For example, it may select a diversity copy mode with a transmission rate level lower than the previously selected diversity copy mode and separated by at least one rate level. For example, TM1, TM4, and TM8 are selected sequentially, i.e., decreasing in a fixed step-by-step manner.

[0068] In other implementations, the transmitting end may repeatedly perform the step of selecting and sending the next signal frame, for example, by determining the next diversity copy mode based on the parameters corresponding to each of the previously selected diversity copy modes. For example, after the first attempt at TM1 and the second attempt at TM5, the next diversity copy mode is adaptively selected based on the parameters corresponding to the diversity copy modes of the two attempts, and the mode is selected as the diversity copy mode that matches the rate level.

[0069] In some other implementations, if the step of selecting and sending the next signal frame is repeated a preset number of times, or if the total duration of sending the signal frame exceeds a preset time threshold and no acknowledgment frame is obtained, the sending end can use the diversity copy mode with the lowest transmission rate among multiple diversity copy modes as the target diversity copy mode and stop trying repeatedly.

[0070] Through the above steps, the transmitting end gradually reduces the transmission rate level, adjusting the selected diversity copy mode to a lower and lower transmission rate until the receiving end can successfully decode and return an acknowledgment frame, thereby determining a diversity copy mode that can be correctly decoded by the receiving end under the current channel conditions.

[0071] Step 240: Determine the target diversity copy mode based on the selected diversity copy mode, and transmit data in the target diversity copy mode.

[0072] Among them, the selected diversity copy mode refers to all diversity copy modes that have been selected and used to send signal frames during the communication mode selection process, from the start of the probe to the receipt of the acknowledgment frame. These include the first diversity copy mode, the second diversity copy mode, and subsequent repeated selections of diversity copy modes.

[0073] The target diversity copy mode refers to the diversity copy mode determined by the sending end based on the information or parameters of the selected diversity copy modes, and is used for the formal transmission of the data to be transmitted.

[0074] After receiving the acknowledgment frame, the sending end does not directly use the current diversity copy mode (i.e., the one corresponding to the last successful decoding) as the target diversity copy mode. Instead, it makes a comprehensive judgment based on the information of all the diversity copy modes selected from the start of the trial to the receipt of the acknowledgment frame to determine the final target diversity copy mode. Then, it modulates and performs diversity copy processing on the data to be transmitted using the target diversity copy mode and sends the data to be transmitted to the receiving end through power line channels or other means.

[0075] In some implementations, the transmitting end may, for example, comprehensively evaluate the parameter information of each selected diversity copy mode, and then match the corresponding diversity copy mode as the target diversity copy mode based on the comprehensive evaluation result. For example, the parameter information includes, but is not limited to, one or more of the following: modulation scheme, number of copies, or signal-to-noise ratio threshold for each diversity copy mode.

[0076] For example, if the transmitter receives an acknowledgment frame after its first attempt at TM1 (QPSK, 2 copies) and its second attempt at TM2 (QPSK, 4 copies), then the modulation schemes and copy counts of TM1 and TM2 are comprehensively evaluated, and a target diversity copy mode is matched based on the evaluation result. This target diversity copy mode might be TM3 (QPSK, 7 copies), which is the diversity copy mode determined after combining the information from the two attempts.

[0077] In other implementations, the sending end may, for example, perform a weighted average or table lookup matching on the transmission rate levels of the selected diversity copy modes to determine the target diversity copy mode.

[0078] In some other implementations, the transmitting end may, for example, combine and calculate the signal-to-noise ratio thresholds corresponding to each of the selected diversity copy modes to obtain the combined signal-to-noise ratio, and then select the diversity copy mode that matches the combined signal-to-noise ratio as the target diversity copy mode.

[0079] In a feasible implementation, if the step of selecting and sending the next signal frame is repeated a preset number of times without obtaining an acknowledgment frame, the sending end can use the diversity copy mode with the lowest transmission rate among multiple diversity copy modes as the target diversity copy mode.

[0080] Through the above steps, the transmitting end incorporates the information of each diversity copy mode selected during multiple trials into the decision of the target diversity copy mode, thereby improving the matching degree between the determined target diversity copy mode and the current channel conditions and avoiding channel quality estimation deviations that may be caused by relying solely on a single diversity copy mode.

[0081] The HPLC communication mode selection method based on an OFDM system provided by the present invention sends a first signal frame in a first diversity copy mode, so that the receiving end decodes the first signal frame. Firstly, it attempts to transmit data to the receiving end at a higher transmission rate to avoid unnecessarily reducing the transmission rate when channel conditions permit. Subsequently, if no confirmation frame indicating successful decoding is obtained, it indicates that a second diversity copy mode with a lower transmission rate than the first diversity copy mode should be selected under the current channel conditions. Then, a second signal frame is sent in the second diversity copy mode. That is, by reducing the transmission rate to adapt to the current channel quality, the probability of retransmission failure due to insufficient channel conditions is effectively reduced. After this, if... If no acknowledgment frame is obtained, the process of selecting and sending the next signal frame is repeated until a acknowledgment frame is obtained. This maintains a relatively high transmission rate by iteratively reducing the transmission rate while ensuring data transmission reliability. Finally, a target diversity copy mode is determined based on the selected diversity copy mode, and data is transmitted using the target diversity copy mode. The comprehensive decision on the diversity copy mode is based on the information from multiple selected diversity copy modes, avoiding channel quality estimation deviations and insufficient or excessive rate redundancy caused by relying solely on a single diversity copy mode when decoding is successful. This allows the determined target diversity copy mode to adaptively match the current channel conditions, achieving high-efficiency and high-reliability data transmission.

[0082] When the channel environment is favorable, in some embodiments, the transmitting end sends a first signal frame in a first diversity copy mode. After the receiving end decodes the first signal frame, if it receives an acknowledgment frame indicating successful decoding, it means that the current channel conditions can support the transmission rate level corresponding to the first diversity copy mode. In this case, the first diversity copy mode can be used as the target diversity copy mode, and the data to be transmitted can be modulated and sent using this target diversity copy mode. In this scenario, the transmitting end can quickly converge to a suitable diversity copy mode without needing to perform rate-reduction testing, which is beneficial for improving communication efficiency.

[0083] In some communication scenarios, channel quality may deteriorate drastically (such as sudden noise or strong attenuation in power line channels). If the transmitter only gradually reduces the transmission rate level (e.g., from TM1 to TM2 and then to TM3), it will require multiple trials to reach a rate level that matches the current channel conditions, leading to increased mode selection delay and reduced communication efficiency. Especially when the signal-to-noise ratio (SNR) corresponding to the channel quality is much lower than the SNR threshold corresponding to the current rate level, the gradual rate reduction method will cause unnecessary signaling overhead and delay.

[0084] Based on this, in some embodiments, the second diversity copy mode is separated from the first diversity copy mode by at least one rate level.

[0085] Here, "separated by at least one rate level" means that the second diversity copy mode is separated from the first diversity copy mode by one or more intermediate rate levels. For example, if multiple diversity copy modes are arranged in descending order of transmission rate level as TM1, TM2, TM3, TM4, etc., then "separated by at least one rate level" means that there is at least one unselected intermediate rate level TM2 or TM3 between the second diversity copy mode and the first diversity copy mode TM1.

[0086] If the transmitter does not receive an acknowledgment frame, it does not select the next rate level adjacent to the first diversity copy mode as the second diversity copy mode. Instead, it selects a mode that is at least one rate level apart as the second diversity copy mode, skipping levels. For example, if the first diversity copy mode is TM1 (the highest transmission rate level), the second diversity copy mode can be TM4 (separated from TM1 by two rate levels, TM2 and TM3), instead of selecting TM2 step by step.

[0087] It should be noted that in some embodiments, after the second diversity copy mode can be successfully decoded by the receiving end (i.e., the sending end receives the acknowledgment frame), the sending end will still determine the target diversity copy mode based on the selected diversity copy modes (including the first diversity copy mode and the second diversity copy mode). This ensures that even if the rate of the second diversity copy mode is too low, the target diversity copy mode can be compensated and corrected through joint calculation and other methods, so as not to result in an excessively low final transmission rate due to excessively large jumps between levels.

[0088] In the above embodiments, by selecting a second diversity copy mode that is at least one rate level away from the first diversity copy mode, the rate level that matches the channel conditions can be quickly reduced with fewer attempts, thereby effectively reducing the number of copy mode selection interactions, reducing mode selection latency, and improving the efficiency of communication link establishment.

[0089] When the transmitter selects the next diversity copy mode in a step-by-step manner, if the channel conditions are only slightly worse than the current diversity copy mode, an excessively large step may lead to excessive rate redundancy; if the channel conditions are much worse than the current diversity copy mode, an insufficient step may require multiple attempts.

[0090] Based on this, in some embodiments, the step of repeatedly selecting and sending the next signal frame includes: obtaining equivalent diversity parameters based on the signal-to-noise ratio parameters corresponding to each of the selected diversity copy modes; obtaining equivalent combined signal-to-noise ratio based on the ratio of the equivalent diversity parameters to the reference signal-to-noise ratio; selecting the next diversity copy mode whose transmission rate level is lower than the rate level corresponding to the equivalent combined signal-to-noise ratio, and sending the next signal frame in the next diversity copy mode.

[0091] Here, the selected diversity copy mode refers to the set of all diversity copy modes selected and used to transmit signal frames by the sending end from the start of the current communication mode selection process to the current moment. In some embodiments, the selected diversity copy mode may be a set including a first diversity copy mode and a second diversity copy mode; in other embodiments, the selected diversity copy mode may be a set including the first diversity copy mode, the second diversity copy mode, and various diversity copy modes selected in subsequent iterations.

[0092] The signal-to-noise ratio (SNR) parameter refers to the parameter corresponding to each diversity copy mode, used to characterize the relationship between the demodulation and decoding performance of that mode and the SNR. In some implementations, the SNR parameter includes, but is not limited to, one or more of the following: the number of copies and the modulation mode coefficient. The number of copies refers to the number of times the diversity copy mode repeatedly transmits the same data symbol; the modulation mode coefficient is a coefficient used to characterize the difference in SNR required by different modulation methods to achieve the same decoding performance. For example, the modulation mode coefficient of BPSK can be 1, and the modulation mode coefficient of QPSK can be 2.

[0093] In feasible implementations, the signal-to-noise ratio (SNR) parameter may further include the SNR threshold corresponding to each diversity copy mode. The SNR threshold refers to the minimum SNR value required for each diversity copy mode to be correctly demodulated.

[0094] The equivalent diversity parameter is a parameter obtained by comprehensively calculating the signal-to-noise ratio (SNR) parameters corresponding to each selected diversity copy mode. It is used to characterize the accumulated equivalent diversity gain of multiple selected diversity copy modes. In feasible implementations, the equivalent diversity parameter is measured in terms of the equivalent copy number under a reference modulation scheme (such as BPSK), so that diversity copy modes with different modulation schemes and different copy numbers can be accumulated and compared on the same metric scale.

[0095] The transmitter first obtains the signal-to-noise ratio parameters corresponding to each of the previously selected diversity copy modes. In some implementations, the transmitter can determine the number of copies and modulation mode coefficients corresponding to each diversity copy mode based on the modulation scheme of each selected diversity copy mode.

[0096] The reference signal-to-noise ratio (SNR) refers to a preset reference SNR value used as a benchmark for measuring the equivalent diversity gain. In feasible implementations, the reference SNR can be the SNR threshold for one copy of BPSK modulation (i.e., the minimum SNR required for correct demodulation of BPSK modulation with one copy). The equivalent combined SNR refers to the estimated SNR obtained by converting the SNR parameters corresponding to each selected diversity copy mode into the equivalent gain under the reference SNR, and is used to characterize the equivalent SNR level achieved after multiple diversity copy combinations.

[0097] After obtaining the equivalent diversity parameters, the transmitting end calculates the equivalent combined signal-to-noise ratio (SNR) based on the ratio of the equivalent diversity parameters to the reference SNR. It should be noted that since the equivalent diversity parameters are measured in units of the equivalent copy number under the reference modulation scheme, multiplying them by the reference SNR yields an estimated SNR value after equivalent copy number of diversity modes and combining them under the reference modulation scheme. This equivalent combined SNR reflects the equivalent reception quality accumulated from the selected diversity copy modes.

[0098] In some implementations, the reference signal-to-noise ratio can be stored locally at the transmitter, which can then directly read it when it needs to calculate the equivalent combined signal-to-noise ratio.

[0099] In other implementations, the reference signal-to-noise ratio (SNR) can also be other preset values. For example, the reference SNR can be set to the demodulation SNR value corresponding to a certain fixed diversity copy mode (such as the lowest rate mode). It should be noted that using different reference SNRs only changes the absolute value of the equivalent combined SNR, and does not affect the subsequent logic for comparison and selection based on the SNR thresholds of each mode. In other words, the specific value of the reference SNR does not affect the mode selection result.

[0100] The next diversity copy mode refers to the diversity copy mode selected by the transmitter in the current iteration based on the equivalent combined signal-to-noise ratio (SNR) for transmitting the next signal frame. In other words, the next diversity copy mode is different from the previously selected diversity copy modes, and its transmission rate level is lower than the rate level corresponding to the equivalent combined SNR.

[0101] After obtaining the equivalent combined signal-to-noise ratio, the transmitting end determines the rate level corresponding to the equivalent combined signal-to-noise ratio, and then selects the next diversity copy mode with a transmission rate level lower than that rate level from multiple diversity copy modes, and sends the next signal frame in the next diversity copy mode.

[0102] In some implementations, the transmitter locally stores the correspondence between each diversity copy mode and the rate level and signal-to-noise ratio threshold. By looking up a table or comparing, the transmitter can determine the rate level range or signal-to-noise ratio threshold range into which the equivalent combined signal-to-noise ratio falls, and then select a diversity copy mode lower than that rate level as the next diversity copy mode.

[0103] It should be noted that the equivalent combined signal-to-noise ratio (SNR) represents the SNR level achievable after the accumulation of all selected modes, while the SNR threshold corresponding to the next diversity copy mode is the minimum SNR required for demodulation of the diversity copy mode alone. Since the equivalent combined SNR already includes the accumulated gain of multiple diversity copy modes, it is not necessary to select a mode with an SNR exactly equal to the equivalent combined SNR. Alternatively, a mode with a rate level lower than the rate level corresponding to the equivalent combined SNR can be selected, ensuring that the signal frame transmitted by the selected next diversity copy mode can be successfully demodulated at the currently accumulated equivalent SNR level.

[0104] In some implementations, the transmitting end can select the diversity copy mode that has a signal-to-noise ratio threshold lower than the equivalent combined signal-to-noise ratio and the smallest difference between it and the equivalent combined signal-to-noise ratio from among multiple diversity copy modes as the next diversity copy mode.

[0105] In other implementations, the transmitter may select the mode with the highest transmission rate among multiple diversity copy modes whose signal-to-noise ratio threshold is lower than the equivalent combined signal-to-noise ratio as the next diversity copy mode.

[0106] In some other implementations, if the signal-to-noise ratio threshold of all diversity copy modes is not lower than the equivalent combined signal-to-noise ratio, then the diversity copy mode with the lowest transmission rate level among the multiple diversity copy modes is selected as the next diversity copy mode.

[0107] For example, suppose multiple diversity copy modes are numbered TM1 to TM8 in descending order of rate level, with their corresponding signal-to-noise ratio (SNR) thresholds increasing. If the equivalent combined SNR is between the SNR thresholds of TM3 and TM4, then the rate level corresponding to the equivalent combined SNR is between TM3 and TM4. The transmitter selects the next diversity copy mode with a rate level lower than this one, such as TM5 or TM6.

[0108] In a feasible implementation, if the transmitter does not receive an acknowledgment frame after sending the next signal frame in the next diversity copy mode, it will enter the next iteration. The signal-to-noise ratio parameter of the next diversity copy mode selected this time will also be included in the calculation of the equivalent diversity parameter. The equivalent combined signal-to-noise ratio will be updated, and a lower mode will continue to be selected until an acknowledgment frame is received.

[0109] It should be noted that diversity copy modes may have the same signal-to-noise ratio (SNR) threshold. In this case, these diversity copy modes with the same SNR threshold have the same SNR threshold, but their modulation schemes and copy counts differ, while their transmission rates are the same. Once the equivalent combined SNR is determined, if the rate level corresponding to the equivalent combined SNR falls within the rate level range of the multiple diversity copy modes with the same SNR threshold, the transmitter selects one of the multiple diversity copy modes as the next diversity copy mode. For example, the transmitter can select one from multiple diversity copy modes, such as a diversity copy mode with a higher modulation order or a diversity copy mode with a different copy count.

[0110] In the above embodiments, the equivalent combined signal-to-noise ratio (SNR) is calculated based on the SNR parameters of each selected diversity copy mode, and the next diversity copy mode is adaptively selected according to the equivalent combined SNR. This allows the transmitter to use the accumulated information of each tried diversity copy mode to quantify the current channel conditions, thereby achieving adaptive matching between the diversity copy mode and the channel quality. This reduces the number of diversity copy mode selections while avoiding excessive rate redundancy, further improving the efficiency and accuracy of mode selection.

[0111] In some implementations, the signal-to-noise ratio (SNR) parameter includes a copy number parameter and a modulation mode coefficient. Based on the SNR parameters corresponding to each of the selected diversity copy modes, an equivalent diversity parameter is obtained, specifically including: obtaining the copy number parameter and modulation mode coefficient corresponding to each of the selected diversity copy modes; calculating the ratio of the copy number parameter to the modulation mode coefficient for each selected diversity copy mode, and summing the ratios to obtain the equivalent diversity parameter.

[0112] The copy count parameter refers to the number of copies performed in the diversity copy mode, or a parameter proportional to the copy count, used to characterize the diversity repetition of the diversity copy mode. In some implementations, a larger copy count parameter results in higher diversity copy gain, but the transmission rate will decrease accordingly.

[0113] Modulation mode coefficients are coefficients used to characterize the difference in signal-to-noise ratio required by different modulation schemes to achieve the same decoding performance. They are used to convert the diversity gain under different modulation schemes to the same reference. In some implementations, modulation mode coefficients may be, for example, the number of bits transmitted per unit symbol under different modulation schemes, or they may be positive integer parameters preset according to actual conditions.

[0114] The transmitting end obtains the copy count parameter and modulation mode coefficient corresponding to each previously selected diversity copy mode; then, for each selected diversity copy mode, it calculates the ratio of its copy count to the modulation mode coefficient; finally, it sums up the ratios of all selected modes and uses the sum as the equivalent diversity parameter.

[0115] In the above embodiments, the equivalent diversity parameter is obtained by summing the copy counts of each diversity copy mode by their respective modulation mode coefficients. This allows diversity copy modes with different modulation schemes and copy counts to be uniformly measured and accumulated under the same benchmark. This eliminates the impact of differences in signal-to-noise ratio requirements caused by different modulation orders on the calculation of the equivalent diversity parameter, and allows the signal-to-noise ratio parameters of each trial to be accumulated under a unified measurement scale, thereby improving the accuracy of the equivalent diversity parameter calculation.

[0116] In some embodiments, a diversity copy mode matching the equivalent diversity parameters is selected as the target diversity copy mode. Specifically, this includes: if BPSK modulation is used, a diversity copy mode with a copy number equal to the equivalent diversity parameters is selected as the target diversity copy mode; if QPSK modulation is used, a diversity copy mode with a copy number twice that of the equivalent diversity parameters is selected as the target diversity copy mode; if 16QAM modulation is used, a diversity copy mode with a copy number ten times that of the equivalent diversity parameters is selected as the target diversity copy mode.

[0117] After determining the equivalent diversity parameters, the sending end determines the target diversity copy mode based on the equivalent diversity parameters.

[0118] If BPSK modulation is desired (e.g., modulation mode coefficient is 1), select a diversity copy mode with a copy number equal to the equivalent diversity parameter; if QPSK modulation is desired (e.g., modulation mode coefficient is 2), select a diversity copy mode with a copy number twice that of the equivalent diversity parameter as the target diversity copy mode; if 16QAM (16-ary Quadrature Amplitude Modulation) is desired, select a diversity copy mode with a copy number ten times that of the equivalent diversity parameter as the target diversity copy mode.

[0119] It should be noted that the purpose of the above settings is to convert the equivalent diversity parameters into the corresponding number of copies for each modulation scheme based on the differences in signal-to-noise ratio (SNR) requirements. This ensures that the matched target diversity copy mode has consistent actual transmission performance under different modulation schemes. Specifically, taking the equivalent number of copies under BPSK modulation as a benchmark, since QPSK modulation requires approximately 3 dB higher SNR than BPSK modulation to achieve the same bit error rate with the same number of copies, the equivalent diversity parameters need to be multiplied by 2 (corresponding to a 3 dB noise power factor) to convert them into the number of copies under QPSK modulation. Similarly, 16QAM modulation requires approximately 10 dB higher SNR than BPSK modulation with the same number of copies, so the equivalent diversity parameters need to be multiplied by 10. Through the above conversion, the actual transmission performance corresponding to the target diversity copy mode under different modulation schemes remains consistent with the cumulative gain represented by the equivalent diversity parameters, thus ensuring the accuracy of the selection of the target diversity copy mode.

[0120] For example, assume the equivalent diversity parameter is 3. If BPSK modulation is desired, the diversity copy mode with 3 copies is selected as the target diversity copy mode; if QPSK modulation is desired, the diversity copy mode with 6 copies (3×2) is selected as the target diversity copy mode; if 16QAM modulation is desired, the diversity copy mode with 30 copies (3×10) is selected as the target diversity copy mode. If no existing diversity copy mode has a copy count exactly equal to the calculated value, the mode with the closest copy count can be selected as the target diversity copy mode.

[0121] Furthermore, in some implementations, the selection of the target modulation scheme can be predetermined based on system requirements or dynamically adjusted according to channel conditions. For example, when the channel quality is good, a higher-order modulation scheme such as QPSK can be selected to improve spectral efficiency, while when the channel quality is poor, BPSK modulation can be selected to ensure demodulation reliability.

[0122] Based on the BPSK modulation scheme, the equivalent diversity parameters are calculated using the following formula: (1) in, For equivalent diversity parameters, This indicates the number of selected diversity copy modes. Indicates the first The number of copies for the currently selected diversity copy mode. Indicates the first The modulation mode coefficients of the selected diversity copy mode.

[0123] Assuming the two diversity copies are successfully merged, for example, let's say the selected diversity copy modes include TM1 (QPSK modulation, copy count 2) and TM5 (BPSK modulation, copy count 2). In this case, the modulation mode coefficients for QPSK are 2, and the modulation mode coefficients for BPSK are 1. Then the ratio for TM1 is 2 / 2 = 1, and the ratio for TM5 is 2 / 1 = 2. The equivalent diversity parameter is the sum of the two, i.e. The value is 3.

[0124] set up The reference signal-to-noise ratio (SNR) is based on the BPSK modulation scheme, and the equivalent combined SNR is... Satisfy the following formula: (2) As can be seen from the above formula, when the signal-to-noise ratio threshold modulation of BPSK modulation for one copy is used as the reference signal-to-noise ratio, the performance achieved by two diversity copies is equivalent to the performance achieved by three diversity copies under BPSK modulation, the performance achieved by six diversity copies under QPSK modulation, and the performance achieved by 30 diversity copies under 16QAM modulation.

[0125] The reason for the above conversion is that different modulation schemes require different signal-to-noise ratios (SNRs) for the same number of copies. Compared to BPSK, QPSK requires a 3 dB higher SNR to achieve the same bit error rate, meaning its required SNR is twice that of BPSK. Therefore, under the same diversity gain, QPSK requires twice the number of copies as BPSK. Similarly, 16QAM requires approximately 10 dB higher SNR than BPSK, meaning its required SNR is ten times that of BPSK. Therefore, under the same diversity gain, 16QAM requires ten times the number of copies as BPSK. Based on these differences, multiplying the equivalent diversity parameter (equivalent copy count based on BPSK) by the modulation mode coefficients corresponding to each modulation scheme yields the number of copies required to match the equivalent diversity parameter for each modulation scheme.

[0126] In the above embodiments, by converting the equivalent diversity parameters into the target copy number under each modulation mode according to the modulation mode coefficients of different modulation methods, the corresponding diversity copy mode can be accurately matched based on the same equivalent diversity parameters under different modulation modes such as BPSK, QPSK and 16QAM. This avoids mismatch of copy number due to different modulation modes and improves the accuracy of target diversity copy mode selection.

[0127] In some embodiments, if no acknowledgment frame is received after repeatedly performing the step of selecting and sending the next signal frame a preset number of times, the diversity copy mode of the lowest transmission rate level is used as the target diversity copy mode.

[0128] The preset number of attempts refers to a pre-defined maximum threshold number of attempts. The iteration terminates when the number of times the sending end repeatedly selects and sends the next signal frame reaches this preset number. For example, the preset number of attempts could be 3, 5, or 8.

[0129] The lowest transmission rate level refers to the mode with the lowest transmission rate among multiple diversity copy modes, that is, the diversity copy mode corresponding to the lowest equivalent transmission rate, the maximum number of copies, and the strongest noise resistance.

[0130] During the process of repeatedly selecting and sending the next signal frame, the sending end counts the number of attempts. When the number of attempts reaches a preset number (e.g., N times), if no acknowledgment frame is received, the iterative probing stops, and signal frames are no longer sent. Instead, the mode with the lowest transmission rate among the multiple diversity copy modes is directly determined as the target diversity copy mode, and the data to be transmitted is modulated and sent using this lowest rate mode.

[0131] For example, suppose the preset number of attempts is 3. The sender fails to send the first signal frame with TM1, fails to send the second signal frame with TM4, and fails to send the third signal frame with TM7. At this point, the number of attempts has reached 3, but no acknowledgment frame has been received. Therefore, the sender will stop trying and directly use TM8 (BPSK, 11 copies, minimum rate mode) as the target diversity copy mode, and send the data to be transmitted with TM8.

[0132] In some implementations, the preset number of attempts can be less than or equal to the total number of diversity copy modes. For example, if there are a total of 8 diversity copy modes (TM1~TM8), the preset number of attempts can be set to 5, and after all 5 attempts fail, data is transmitted directly in the lowest rate mode TM8.

[0133] In other implementations, the preset number of times can be pre-set by the system according to the application scenario. For example, in scenarios with high real-time requirements, it can be set to a smaller value (such as 3 times) to achieve fast convergence, while in scenarios with high reliability requirements, it can be set to a larger value (such as 8 times) to find a better diversity copy mode.

[0134] In the above embodiments, by setting a preset number of iterations as the termination condition, and directly using the diversity copy mode with the lowest transmission rate level as the target diversity copy mode after reaching the preset number of iterations, a reasonable termination boundary is set for the diversity copy mode selection process of the sending end. This avoids unlimited repeated attempts under extreme channel conditions that could lead to the failure to establish a communication link, and can maximize the guarantee that data can still be successfully transmitted under poor channel conditions, thereby improving the robustness of the system.

[0135] Based on the same inventive concept, this invention also provides an HPLC communication mode selection method based on an OFDM system, applied at the receiving end. The executing entity of this method can be the receiving end, or a functional module or entity within the receiving end capable of implementing this method.

[0136] The following describes the HPLC communication mode selection method based on the OFDM system provided in this embodiment of the invention, taking the receiving end as the executing entity as an example.

[0137] Figure 3 This is a flowchart illustrating the HPLC communication mode selection method based on an OFDM system provided in other embodiments of the present invention. For example... Figure 3 As shown, the HPLC communication mode selection method based on the OFDM system includes steps 310 to 370.

[0138] Step 310: When the first signal frame sent by the sending end in the first diversity copy mode is received, the first LLR value corresponding to the first signal frame is obtained.

[0139] Here, the first LLR value refers to the log-likelihood ratio (LLR) value corresponding to each bit obtained by the receiving end after demodulating and performing batch union and other processing on the data carried by the first signal frame. For example, if the data of the first signal frame contains K bits, then the first LLR value includes K LLR values, each corresponding to one of the K bits.

[0140] In some implementations, the receiving end demodulates the received first signal frame, performs a diversity copying of the demodulated signal according to the number of copies corresponding to the first diversity copy mode, and then calculates the LLR value corresponding to each bit in the data of the first signal frame based on the diversity copying signal to obtain the first LLR value.

[0141] In some implementations, after the receiving end calculates the first LLR value, it saves the first LLR value to a local buffer so that it can be merged with the LLR value of subsequent signal frames in the event of subsequent decoding failure.

[0142] Step 320: Decode the first signal frame based on the first LLR value.

[0143] Decoding refers to the process by which the receiving end processes the received signal frame to recover the data carried by the signal frame. For example, decoding can be one or more of hard-decision decoding or soft-decision decoding.

[0144] In some implementations, the receiving end decodes the first LLR value to obtain a decoded bit sequence; then, it performs a verification process on the decoded bit sequence. If the verification passes, the first signal frame is determined to have been successfully decoded; if the verification fails, the first signal frame is determined to have failed to be decoded. For example, the verification process may be a Cyclic Redundancy Check (CRC).

[0145] It should be noted that if decoding fails, the receiving end will save the first LLR value, which will be used to merge with the LLR value of the second signal frame before decoding, in order to improve the decoding success rate by utilizing the accumulated information from multiple transmissions.

[0146] Step 330: If decoding fails, a negative frame is sent back to the sending end so that after receiving the negative frame, the sending end selects a second diversity copy mode with a transmission rate level lower than the first diversity copy mode to send the second signal frame.

[0147] In this context, a negation frame is a feedback frame used to indicate that decoding at the receiving end has failed. The receiving end sends a negation frame to the sending end after a decoding failure, so that the sending end is aware that the current diversity copy mode cannot be successfully demodulated. For example, a negation frame could be a NACK frame.

[0148] The receiving end generates a negative frame and sends it to the sending end. After receiving the negative frame, the sending end determines the second diversity copy mode according to the preset mode selection rules (such as step-by-step speed reduction or cross-level speed reduction), and retransmits the signal frame in the second diversity copy mode.

[0149] It should be noted that the receiving end saves the first LLR value after the decoding fails, so that when the second signal frame is received in the future, the two LLR values ​​can be merged and decoded, and the cumulative information of the two transmissions can be used to improve the decoding success rate.

[0150] In some implementations, the receiving end may not send a negative frame after decoding failure, but instead waits, and the sending end determines that decoding has failed if it does not receive any feedback frame within a preset time.

[0151] Step 340: Receive the second signal frame, obtain the second LLR value corresponding to the second signal frame, and merge the second LLR value with the first LLR value to obtain the merged LLR value.

[0152] The second LLR value refers to the log-likelihood ratio of each bit calculated by the receiving end after demodulating and binarizing the data of the second signal frame. If the data carried by the second signal frame contains K bits, then the second LLR value includes K LLR values, each corresponding to one of the K bits.

[0153] In some implementations, the receiving end merges the second LLR value with the first LLR value, for example, by directly adding the second LLR value and the first LLR value according to their corresponding bit positions.

[0154] In other implementations, the receiver may also combine the second LLR value with the first LLR value. For example, it may assign weights to each LLR value based on the signal-to-noise ratio threshold or confidence level corresponding to different diversity copy modes and then add them together.

[0155] Step 350: Decode the second signal frame based on the merged LLR value.

[0156] The receiving end decodes the merged LLR value to obtain the decoded bit sequence. Subsequently, the receiving end performs a checksum verification on the decoded bit sequence. If the checksum passes, decoding is considered successful; if the checksum fails, decoding is considered unsuccessful. For example, the checksum verification could be a Cyclic Redundancy Check (CRC).

[0157] Step 360: If decoding is successful, send an acknowledgment frame to the sender so that the sender can determine the target diversity copy mode based on the selected diversity copy mode and transmit data in the target diversity copy mode.

[0158] If the receiving end successfully decodes the second signal frame based on the merged LLR value, it sends an acknowledgment frame back to the sending end. This allows the sending end to determine the target diversity copy mode based on the selected diversity copy mode after receiving the acknowledgment frame, and to modulate and transmit the data to be transmitted in the target diversity copy mode.

[0159] After generating an acknowledgment frame, the receiving end sends it to the sending end. Upon receiving the acknowledgment frame, the sending end no longer selects a diversity copy mode with a lower transmission rate, but instead determines the target diversity copy mode based on the information of the selected diversity copy modes.

[0160] In some implementations, the receiving end may also carry auxiliary information (such as one or more of the current channel quality indication, recommended mode, etc.) in the acknowledgment frame while sending the acknowledgment frame, so that the sending end can determine the target diversity copy mode based on the auxiliary information.

[0161] Step 370: If decoding still fails, continue to send a negative frame to the sender to trigger the sender to repeat the step of selecting and sending the next signal frame until decoding is successful.

[0162] The receiving end generates a negative frame and sends it to the sending end. After receiving the negative frame, the sending end calculates the equivalent diversity parameters and equivalent combined signal-to-noise ratio based on the selected diversity copy modes, and selects the next diversity copy mode with a lower transmission rate level to send the next signal frame.

[0163] It should be noted that the receiver saves the latest merged LLR value (i.e., the merged result of the LLR values ​​of all previously received signal frames) after each decoding failure. For example, after the first decoding failure, the first LLR value is saved; after the second decoding failure, the merged LLR value of the first and second LLR values ​​is saved; after the third decoding failure, the merged LLR value is saved and then merged with the third LLR value again, and so on. In each iteration, the receiver merges the LLR value of the newly received signal frame with the previously saved merged LLR value, so that the equivalent signal-to-noise ratio increases with the number of iterations, thereby gradually improving the decoding success rate.

[0164] Through the above steps, when decoding is successful, an acknowledgment frame is sent to notify the sender to terminate the probe and determine the target mode; when decoding fails, a negation frame is sent to trigger the sender to continue sending signal frames in a diversity copy mode with a lower transmission rate until decoding is successful or the preset termination condition is met.

[0165] According to the HPLC communication mode selection method based on an OFDM system provided by the present invention, when a first signal frame is received from the transmitter in a first diversity copy mode, a first LLR value corresponding to the first signal frame is obtained, and the first signal frame is decoded based on the first LLR value, thereby using the calculated information of the received signal to determine the decoding result of the current signal frame; subsequently, if decoding fails, a negative frame is fed back to the transmitter, so that the transmitter selects a second diversity copy mode with a lower transmission rate level than the first diversity copy mode to send a second signal frame after receiving the negative frame; thereby triggering the transmitter to select a diversity copy mode with a lower transmission rate level to adapt to the current channel conditions through a feedback mechanism; after this, the second signal frame is received, the second LLR value corresponding to the second signal frame is obtained, and the second LLR value is used to determine the decoding result of the current signal frame. The LLR value is merged with the first LLR value to obtain a merged LLR value. The second signal frame is then decoded based on this merged LLR value, utilizing the confidence information of the first and second signal frames fused by the merged LLR value to improve the decoding success rate. If decoding is successful, an acknowledgment frame is sent back to the transmitter, enabling the transmitter to determine the target diversity copy mode based on the selected diversity copy mode and transmit data according to that mode. If decoding still fails, a negation frame is sent back to the transmitter, triggering the transmitter to repeat the process of selecting and sending the next signal frame until decoding is successful. By progressively accumulating the LLR values ​​of each signal frame, the receiver can gradually improve the decoding success rate through iterative loops without needing to obtain channel quality information beforehand, achieving high-efficiency and high-reliability data transmission.

[0166] In some embodiments, the second LLR value is merged with the first LLR value to obtain a merged LLR value, specifically including: directly adding the second LLR value and the first LLR value according to their corresponding bit positions to obtain the merged LLR value.

[0167] Direct addition refers to arithmetically adding the two LLR values ​​at the same bit position in the first LLR value and the second LLR value to obtain a combined LLR value at that bit position.

[0168] The corresponding bit position refers to the bit index position of the signal frame in the data. Since the first and second signal frames carry data of the same format, the positions of each bit in the frame structure are one-to-one.

[0169] After obtaining the second LLR value, the receiving end performs arithmetic addition on the two LLR values ​​located at the same bit position in the first and second LLR values.

[0170] In the above embodiments, LLR merging is achieved by directly adding the first LLR value and the second LLR value according to their corresponding bit positions. This method can achieve the maximum merging gain, is simple to implement, requires little computation, and is beneficial for low power consumption and fast processing at the receiving end.

[0171] In some embodiments, the receiving end performs soft-decision decoding on the acquired LLR value to obtain the decoded bit sequence; the bit sequence is then subjected to cyclic redundancy check (CRC). If the check passes, the decoding is determined to be successful; if the check fails, the decoding is determined to be unsuccessful.

[0172] Soft-decision decoding refers to directly inputting the LLR value into the decoder for decoding; Cyclic Redundancy Check (CRC) is an error detection method based on CRC codes, used to determine whether there are errors in the decoded bit sequence. When generating a signal frame, the transmitting end appends a CRC check bit to the payload data; after decoding, the receiving end recalculates the CRC value based on the received data and compares it with the received CRC check bit. If they match, the check passes; otherwise, the check fails.

[0173] After receiving the LLR value (which can be the first LLR value received in a single transmission or the combined LLR value after multiple transmissions), the receiver inputs the LLR value into the decoder for soft-decision decoding to obtain the decoded bit sequence. Then, the receiver calculates the CRC checksum based on this bit sequence and compares it with the CRC checksum carried in the currently received signal frame. If they match, the checksum is considered to have passed, and decoding is determined to be successful; if they do not match, the checksum is considered to have failed, and decoding is determined to have failed.

[0174] In a feasible implementation, when decoding is successful, the receiver sends an acknowledgment frame to the sender; when decoding fails, the receiver sends a negation frame to the sender and saves the current LLR value or merges the LLR values, so that they can be merged with the new LLR values ​​again for soft-decision decoding and CRC verification.

[0175] In some implementations, the decoder includes, but is not limited to, one or more of the following: a turbine decoder or a low-density parity decoder.

[0176] In the above embodiments, the bit sequence is obtained through soft-decision decoding, and cyclic redundancy check (CRC) is performed to determine whether the decoding was successful. This accurately judges the validity of each decoding result, avoiding incorrect triggering of mode switching or data transmission due to misjudgment. Simultaneously, soft-decision decoding fully utilizes the confidence information in the LLR value, resulting in higher decoding performance compared to hard-decision decoding and improving the decoding success rate. CRC check, as an accurate and reliable error detection method, can effectively identify the correctness of the decoding result, providing a reliable basis for subsequent LLR merging iterative decoding and feedback decisions.

[0177] It should be noted that in the relevant technologies, the sending end needs to send signal frames for the data used to confirm the diversity copy mode each time according to different diversity copy modes. Since each signal frame is sent independently, the target diversity copy mode used by the sending end ultimately depends on the signal frame of the confirmation frame fed back by the receiving end.

[0178] Therefore, the transmitting end can only adopt the method of selecting diversity copy mode step by step to avoid skipping diversity copy modes that may miss the potential suitable transmission rate; at the same time, since the receiving end does not save the LLR value of the signal frame that failed to be decoded at this time, selecting diversity copy mode across levels means giving up the transmission opportunity of the skipped diversity copy mode, which may result in an excessively low final transmission rate. Therefore, selecting across levels lacks a reasonable basis.

[0179] To address the aforementioned issues, this invention combines the successive accumulation of the LLR values ​​of each signal frame at the receiving end with the cross-level selection diversity copy mode at the transmitting end, thereby enabling the cross-level selection diversity copy mode to be implemented.

[0180] For the receiving end, the failed decoding signal frame is combined with the LLR value of the subsequently received signal frame to obtain a combined LLR value, which is then used to decode subsequent received signal frames. Because multiple received LLR values ​​are combined, the confidence level of the combined LLR value used for decoding is higher than that of a single received signal frame, thus improving the decoding success rate at the receiving end. Furthermore, this method reduces the probability of the sending end failing to receive an acknowledgment frame after selecting a diversity copy mode across stages, allowing the sending end to select diversity copy modes with a larger step size.

[0181] For the receiving end, the process of determining the target diversity copy mode includes: obtaining equivalent diversity parameters based on the number of copies and modulation mode coefficients of each selected diversity copy mode; determining the target diversity copy mode according to the diversity copy mode corresponding to the equivalent diversity parameters; and incorporating the signal-to-noise ratio threshold information corresponding to the skipped intermediate rate levels into the determination of the target diversity copy mode through the calculation of the equivalent diversity parameters of the selected diversity copy modes. This allows for a comprehensive selection of the target diversity copy mode for data transmission after selecting diversity copy modes across different levels, avoiding excessively low transmission rates due to large spans in the final determined diversity copy mode.

[0182] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0183] In some embodiments, Figure 4 These are schematic diagrams of the structure of an electronic device provided in some embodiments of the present invention. For example... Figure 4 As shown, this embodiment of the invention also provides an electronic device 400, including a processor 401, a memory 402, and a computer program stored in the memory 402 and executable on the processor 401. When the program is executed by the processor 401, it implements the various processes of the above-described embodiment of the HPLC communication mode selection method based on the OFDM system and achieves the same technical effect. To avoid repetition, it will not be described again here.

[0184] This invention provides a non-transitory computer-readable storage medium storing a computer program. When executed by a processor, the computer program implements the various processes of the above-described HPLC communication mode selection method embodiment based on an OFDM system and achieves the same technical effect. To avoid repetition, it will not be described again here.

[0185] The processor is the processor in the electronic device described in the above embodiments. The readable storage medium includes computer-readable media, such as computer read-only memory (ROM), random-access memory (RAM), magnetic disks, or optical disks.

[0186] The computer-readable storage medium may include: read-only memory (ROM), random-access memory (RAM), magnetic disk or optical disk, etc.

[0187] This invention provides a computer program product, including a computer program that, when executed by a processor, implements the above-described HPLC communication mode selection method based on an OFDM system.

[0188] This invention provides a chip that includes a processor and a communication interface. The communication interface is coupled to the processor. The processor is used to run programs or instructions to implement the various processes of the above-described HPLC communication mode selection method embodiment based on an OFDM system, and can achieve the same technical effect. To avoid repetition, it will not be described again here.

[0189] It should be understood that the chip mentioned in the embodiments of the present invention may also be referred to as a system-on-a-chip, system chip, chip system, or system-on-a-chip, etc.

[0190] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element. Furthermore, it should be noted that the scope of the methods and apparatuses in the embodiments of the present invention is not limited to performing functions in the order shown or discussed, but may also include performing functions substantially simultaneously or in the reverse order, depending on the functions involved. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.

[0191] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the related technology, can be embodied in the form of a computer software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of the present invention.

[0192] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of the present invention.

[0193] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0194] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A method for selecting HPLC communication modes based on an OFDM system, characterized in that, The method is applied to a transmitting end, which is configured with multiple diversity copy modes, each corresponding to a different transmission rate level; the method includes: The first signal frame is sent in the first diversity copy mode so that the receiving end can decode the first signal frame. If no confirmation frame indicating successful decoding is obtained, a second diversity copy mode with a transmission rate level lower than the first diversity copy mode is selected, and a second signal frame is sent in the second diversity copy mode. If the corresponding acknowledgment frame is still not obtained, repeat the steps of selecting and sending the next signal frame until the corresponding acknowledgment frame is obtained. Obtain the copy count parameter and modulation mode coefficient corresponding to each selected diversity copy mode; Calculate the ratio of the copy number parameter to the modulation mode coefficient for each selected diversity copy mode, and sum the ratios to obtain the equivalent diversity parameter. Select a diversity copy mode that matches the equivalent diversity parameters as the target diversity copy mode, and transmit data using the target diversity copy mode.

2. The HPLC communication mode selection method based on an OFDM system according to claim 1, characterized in that, The second diversity copy mode is separated from the first diversity copy mode by at least one rate level.

3. The HPLC communication mode selection method based on an OFDM system according to claim 1, characterized in that, The step of repeatedly selecting and sending the next signal frame includes: Based on the signal-to-noise ratio parameters corresponding to the selected diversity copy modes, the equivalent diversity parameters are obtained. The equivalent combined signal-to-noise ratio is obtained based on the ratio of the equivalent diversity parameter to the reference signal-to-noise ratio. Select a next diversity copy mode whose transmission rate level is lower than the rate level corresponding to the equivalent combined signal-to-noise ratio, and send the next signal frame in the next diversity copy mode.

4. The HPLC communication mode selection method based on an OFDM system according to claim 1, characterized in that, The step of selecting a diversity copy mode that matches the equivalent diversity parameters as the target diversity copy mode includes: If BPSK modulation is used, select the diversity copy mode with a copy count equal to the equivalent diversity parameter as the target diversity copy mode. If QPSK modulation is used, select the diversity copy mode with a copy count equal to twice the equivalent diversity parameter as the target diversity copy mode; If 16QAM modulation is used, select a diversity copy mode with a copy count equal to ten times the equivalent diversity parameter as the target diversity copy mode.

5. The HPLC communication mode selection method based on an OFDM system according to claim 1, characterized in that, The method further includes: If no acknowledgment frame is received after repeating the step of selecting and sending the next signal frame a preset number of times, the diversity copy mode with the lowest transmission rate level shall be used as the target diversity copy mode.

6. A method for selecting HPLC communication modes based on an OFDM system, characterized in that, Applied to the receiving end, the method includes: When a first signal frame is received from the sender in the first diversity copy mode, the first LLR value corresponding to the first signal frame is obtained. The first signal frame is decoded based on the first LLR value; If decoding fails, a negative frame is sent back to the sending end, so that after receiving the negative frame, the sending end selects a second diversity copy mode with a transmission rate level lower than the first diversity copy mode to send a second signal frame. Receive the second signal frame, obtain the second LLR value corresponding to the second signal frame, and directly add the second LLR value and the first LLR value according to the corresponding bit positions to obtain the merged LLR value; The second signal frame is decoded based on the merged LLR value; If decoding is successful, an acknowledgment frame is sent back to the sending end, so that the sending end determines the target diversity copy mode according to the selected diversity copy mode and transmits data in the target diversity copy mode. If decoding still fails, a negative frame is sent back to the sending end to trigger the sending end to repeat the step of selecting and sending the next signal frame until decoding is successful.

7. The HPLC communication mode selection method based on an OFDM system according to claim 6, characterized in that, The method further includes: The obtained LLR value is soft-determined to obtain the decoded bit sequence; Cyclic redundancy check is performed on the bit sequence. If the check passes, the decoding is considered successful; if the check fails, the decoding is considered unsuccessful.

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