Discrete fragmentation transmission method and system for sparse meteor trail channel

Abstract

The application discloses a discrete fragmentation transmission method and system for an underdense meteor trail channel, and the method comprises the following steps: a sending end adopts an active blind detection mechanism to establish a communication link with a receiving end and locks a communication frequency point; after the communication link is established, the sending end performs deletion error correction coding on original data to be transmitted to generate a coded data stream, and the coded data stream is divided into a plurality of independent discrete fragmented data, and the discrete fragmented data is transmitted on the locked communication frequency point in a set order; the receiving end performs integrity checking on each discrete fragmented data received, and requests the sending end to retransmit the current discrete fragmented data when the checking fails; and the receiving end recovers the original data through a cross-window accumulation mode. The application can greatly improve the utilization rate of a weak underdense meteor channel, effectively reduce the waiting time of a communication system, and improve the reliability of the system.

Description

Technical Field

[0001] This invention belongs to the field of wireless communication technology, specifically relating to a discrete fragmentation transmission method and system for under-dense meteor trail channels. Background Technology

[0002] Meteor trail communication is a technique that utilizes the ionization trails created when meteors enter the atmosphere to reflect or scatter radio waves, enabling beyond-line-of-sight communication. The most significant characteristics of this type of channel are its burstiness and intermittency: the communication window appears randomly and lasts for an extremely short time (typically on the order of tens to hundreds of milliseconds), the window interval is uncertain, and the channel characteristics are significantly affected by multipath effects, frequency shifts, rapid phase changes, and external interference, resulting in an overall propagation environment with high bit error rate and low signal-to-noise ratio.

[0003] Based on the electron density and attenuation characteristics of the residual channels, meteor trail channels can be mainly divided into underdense meteor trail channels and overdense meteor trail channels. Underdense meteor trail channels occur more frequently, but their signal strength is weak, their duration is extremely short (typically tens of milliseconds), and their signal amplitude decays exponentially. Generally, underdense meteor trail channels have extremely short durations, their channel fading follows a negative exponential function, and exhibits large-scale rapid changes, making them unusable by traditional communication methods. Due to the large number of underdense meteor trail channels, the core bottleneck in effectively reducing the average latency of meteor trail communication systems lies in designing novel transmission mechanisms to improve the utilization rate of underdense channels.

[0004] Existing transmission schemes for meteor trail channels are mostly based on the idea of ​​whole packet transmission, that is, after detecting the channel window, they attempt to complete the transmission and acknowledgment of the entire data packet within one or several consecutive long windows. In practical applications, such schemes face the following prominent problems: (1) Long waiting time and high uncertainty: The probability of strong and stable channel windows is low, which means that data packets need to wait for a long time before they can be sent. The service completion delay distribution has a long tail characteristic, which makes it difficult to meet the needs of emergency communication, time-sensitive services and other services for "delivery as soon as possible"; (2) Low utilization of weak windows: A large number of short-lived and weak under-density windows are idle because they are not enough to carry complete data packets or complex handshake processes, resulting in a waste of valuable channel resources; (3) Insufficient robustness: Under conditions of low signal-to-noise ratio, large frequency offset and rapid phase change, once the whole packet transmission fails, it often needs to be retransmitted as a whole, which is inefficient; (4) Poor interruption recovery capability: The transmission process is easily interrupted randomly. If there is a lack of effective breakpoint resumption and cumulative reception mechanism, it is necessary to start from the beginning after each interruption, which seriously affects the continuity of transmission. Summary of the Invention

[0005] To address the aforementioned problems in existing technologies, this invention provides a discrete fragmentation transmission method and system for under-dense meteor trail channels. It aims to solve the problems of low handshake success rate, frequent transmission interruptions, and difficulty in resuming interrupted transmissions in extremely short, bursty, low signal-to-noise ratio, and highly volatile phase channels. By combining multi-frequency blind detection with discrete fragmentation streaming injection, it achieves highly reliable communication at extremely low data rates. The technical problem to be solved by this invention is achieved through the following technical solution: One aspect of the present invention provides a discrete fragmentation transmission method for under-dense meteor trail channels, comprising: S1: The transmitting end uses an active blind detection mechanism to establish a communication link with the receiving end and lock the communication frequency point; S2: After establishing the communication link, the sending end performs deletion and error correction encoding on the original data to be transmitted to generate an encoded data stream, and divides the encoded data stream into multiple independent discrete fragments of data and transmits them on a locked communication frequency in a set order. S3: The receiving end performs integrity verification on each received discrete fragment data and requests the sending end to retransmit the current discrete fragment data if the verification fails; S4: The receiving end recovers the original data by accumulating across windows.

[0006] In one embodiment of the present invention, S1 includes: S1.1: The transmitting end polls and transmits detection signals on multiple preset candidate frequency points; S1.2: After sending the detection signal, the transmitting end enters the monitoring state to wait for the response signal from the receiving end; S1.3: When the receiving end successfully captures the detection signal at the current candidate frequency point, the receiving end sends an acknowledgment signal to the transmitting end; S1.4: After receiving the response signal, the transmitting end locks the current candidate frequency point as the communication frequency point, completes the link handshake, and establishes a communication link.

[0007] In one embodiment of the present invention, S2 includes: S2.1: The sending end performs deletion and error correction encoding based on Reed-Solomon codes on the original data to be transmitted to generate an encoded data stream containing redundant information; S2.2: The encoded data stream is segmented to generate multiple independent discrete data segments, each of which contains an independent data segment to be transmitted, a check bit, and a segmentation index; S2.3: Within the locked communication frequency, the transmitting end uses the discrete fragmented data as the basic transmission unit and continuously transmits it to the receiving end in a streaming manner.

[0008] In one embodiment of the present invention, the check bit is a CRC cyclic redundancy check code, and the check bit of each discrete data segment is formed by performing a CRC operation on the current discrete data segment, and the check bit is appended to the end of the data segment of the current discrete data segment.

[0009] In one embodiment of the present invention, S2.3 includes: The transmitting end uses the discrete fragment data as the basic transmission unit on the locked communication frequency point and continuously transmits it within the available time window using a streaming transmission strategy until the window closes or the data transmission is completed. The streaming transmission method means that the transmitting end does not wait for confirmation of individual discrete fragment data and continuously sends the discrete fragment data until the window closes or the data transmission is completed.

[0010] In one embodiment of the present invention, S3 includes: The receiving end demodulates and verifies the integrity of each received discrete fragment data in real time. If the verification passes, the current discrete fragment data is determined to be valid and the valid discrete fragment data is stored in the reassembly buffer set in the receiving end. If the verification fails, feedback information containing the error fragment index is generated and the feedback information is sent to the sending end to request retransmission. The sending end dynamically adjusts the sending queue based on the feedback information and retransmits the discrete fragment data related to the feedback information.

[0011] In one embodiment of the present invention, S4 includes: The receiving end continuously counts the number of valid discrete fragment data accumulated in the reassembly buffer. When the number of valid discrete fragment data reaches a preset decoding threshold, the data in the reassembly buffer is extracted, rearranged according to the fragment index, and RS decoding is performed. If the decoding is successful, the original data is restored and the transmission task is completed. If the decoding fails, the existing valid discrete fragment data is retained, and the receiver continues to wait for new valid discrete fragment data to be received to participate in the decoding until the decoding is successful.

[0012] Another aspect of the present invention provides a discrete fragmentation transmission system for under-dense meteor trail channels, the system comprising a transmitter and a receiver, wherein, The transmitting end is used to establish a communication link with the receiving end using an active blind detection mechanism and lock the communication frequency point; after establishing the communication link, the original data to be transmitted is deleted, corrected, and encoded to generate an encoded data stream, and the encoded data stream is divided into multiple independent discrete fragments of data and transmitted on the locked communication frequency point in a preset order; The receiving end is used to receive discrete fragment data and perform integrity verification on each received discrete fragment data. If the verification fails, it requests the sending end to retransmit the current discrete fragment data. The receiving end is also used to recover the original data by accumulating across windows.

[0013] In one embodiment of the present invention, the receiving end is provided with a reassembly buffer, which is used to store valid discrete fragment data that has passed verification.

[0014] In one embodiment of the present invention, the transmitting end and the receiving end adopt an asymmetric time slot design. The transmitting end occupies the data transmission time slot to continuously transmit the discrete fragment data in a streaming manner. The receiving end occupies the acknowledgment time slot to centrally feed back the integrity verification result and retransmission request to the transmitting end. When the communication window is closed, causing the data transmission to be interrupted, the transmitting end uses the locked communication frequency point in the subsequent window to directly continue transmitting the unfinished discrete fragment data until the decoding is successful.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention provides a low-overhead discrete fragmentation transmission method and system for bursty channels with weak meteor trails. Addressing the challenges of extremely short duration and weak gain in weak meteor trail channels, this invention employs a low-overhead blind probing mechanism to quickly establish a link. Redundant coding is used to transform the data to be transmitted into a coded data stream containing redundant information, which is then divided into multiple independent discrete fragments. Continuous transmission is implemented under the condition of randomly bursting weak meteor trail channels. At the receiving end, independent integrity checks and cross-window accumulation are performed on the received discrete fragments. When the number of valid fragments reaches the decoding threshold, the original data is decoded and recovered. This invention can significantly improve the utilization rate of weak weak meteor channels, effectively reduce communication system latency, and improve system reliability.

[0016] 2. This invention significantly increases the probability of capturing a usable window in frequency-selective fading meteor trail channels by introducing a multi-frequency transmission and acquisition mechanism, reducing handshake waiting time. Combining streaming injection and feedback retransmission mechanisms, it maximizes data injection during the brief transparency period of the meteor trail channel and solves the problem of partial fragment loss through selective retransmission, achieving efficient breakpoint resumption. Utilizing the characteristics of redundant coding, the receiver can recover data even without receiving all original fragments (only requiring the decoding threshold to be reached), effectively shortening the delivery delay of long messages in intermittent channels. Therefore, addressing the characteristics of "short windows, random occurrence, and weak signals" in low-density meteor trail channels, this invention provides a reliable transmission method that can accumulate and transmit fragments piece by piece within sporadic weak windows, while possessing strong fault tolerance and breakpoint resumption capabilities.

[0017] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0018] Figure 1 This is a flowchart of a discrete fragmentation transmission method for under-dense meteor trail channels provided in an embodiment of the present invention; Figure 2 This is a detailed schematic diagram illustrating the processing steps of a discrete fragmentation transmission method for under-dense meteor trail channels provided in an embodiment of the present invention. Figure 3 This is a comparison diagram of the cumulative delay distribution function of data transmission under different fragmentation configurations using the discrete fragmentation transmission method proposed in this invention. Figure 4 This is a trend analysis graph showing the relationship between the number of fragments and the system receiving sensitivity in the discrete fragmentation transmission method proposed in this invention; Figure 5 This is a comparison chart of the packet loss rate performance of the discrete fragmentation transmission method proposed in this invention under different fragmentation configurations and the traditional full-speed mode under different channel peak powers. Detailed Implementation

[0019] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the following describes in detail, with reference to the accompanying drawings and specific embodiments, a discrete fragmentation transmission method and system for under-dense meteor trail channels proposed in accordance with the present invention.

[0020] The foregoing and other technical contents, features, and effects of the present invention will be clearly presented in the following detailed description of specific embodiments in conjunction with the accompanying drawings. Through the description of the specific embodiments, a more in-depth and concrete understanding can be gained of the technical means and effects adopted by the present invention to achieve its intended purpose. However, the accompanying drawings are for reference and illustration only and are not intended to limit the technical solutions of the present invention.

[0021] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations are intended to cover non-exclusive inclusion, such that an article or apparatus comprising a list of elements includes not only those elements but also other elements not expressly listed. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or apparatus that includes said element.

[0022] Example 1 This embodiment addresses the characteristics of meteor trail channels, such as extremely short communication windows (milliseconds), low signal-to-noise ratios, and severe phase fluctuations, by employing a transmission strategy combining "blind probe link establishment" and "discrete stream injection." Long data packets are broken down into tiny fragments, and data transmission is completed in a "collecting small pieces" manner across multiple scattered channel windows. Please refer to [link to previous document]. Figure 1 and Figure 2 , Figure 1 This is a flowchart of a discrete fragmentation transmission method for under-dense meteor trail channels provided in an embodiment of the present invention. Figure 2 This is a detailed schematic diagram illustrating the processing procedure of a discrete fragmentation transmission method for under-dense meteor trail channels provided by an embodiment of the present invention. It shows the entire process from fragmentation coding at the transmitting end and blind channel detection transmission to reception and reassembly at the receiving end. The transmission method of this embodiment includes the following steps: S1: The transmitting end uses an active blind detection mechanism to establish a communication link with the receiving end and lock the communication frequency. The discrete fragmentation transmission method for under-dense meteor trail channels proposed in this embodiment is implemented based on a discrete fragmentation transmission system, which includes a transmitter and a receiver. Considering the characteristics of strong randomness and short duration of the channel window in meteor trail communication, the transmitter abandons complex handshake interactions and adopts an active blind detection mechanism to establish a communication link with the receiver.

[0023] S1 in this embodiment includes the following steps: S1.1: The transmitting end polls and sends detection signals on multiple preset candidate frequency points.

[0024] The transmitting end configures a candidate frequency set based on the signal transmission frequency. This candidate frequency set includes multiple candidate frequencies. Subsequently, the transmitting end polls and transmits probe signals on these multiple candidate frequencies in a round-robin fashion, i.e., continuously or periodically transmitting probe signals. These probe signals are short-time characteristic waveforms used by the receiving end for signal acquisition. Specifically, the transmitting end polls the candidate frequencies in priority order, transmitting a probe signal once for each frequency.

[0025] S1.2: After sending the probe signal, the transmitting end enters the monitoring state to wait for the response signal from the receiving end.

[0026] S1.3: When the receiver successfully captures the detection signal at the current candidate frequency point, the receiver sends an acknowledgment signal to the transmitter. The receiver performs parallel blind search on the multiple candidate frequencies. Once it successfully captures the probe signal at a candidate frequency, it determines that the current candidate frequency is available and sends an acknowledgment signal (ACK signal) to the transmitter at that candidate frequency. The purpose of the acknowledgment signal is to inform the transmitter that the current candidate frequency is available for communication, thereby terminating the probe polling.

[0027] S1.4: After receiving the response signal, the transmitting end locks the current candidate frequency as the communication frequency, completes the link handshake, and establishes the communication link.

[0028] It should be noted that since the optimal receiving frequency depends only on the local electromagnetic environment, and the electromagnetic environment is assumed to remain unchanged throughout the entire transmission cycle, the locked communication frequency remains valid until decoding is successful and does not need to be renegotiated with window switching.

[0029] S2: After establishing a communication link, the sending end performs deletion and error correction encoding on the original data to be transmitted to generate an encoded data stream, and then divides the encoded data stream into multiple independent discrete fragments of data and transmits them on a locked communication frequency in a set order.

[0030] After establishing a communication link, the sending end initiates the data transmission process. In this embodiment, the sending end adopts a "break down" strategy for data transmission, specifically including the following steps: S2.1: The sending end performs deletion and error correction encoding based on Reed-Solomon (RS) code on the original data to be transmitted to generate an encoded data stream; RS code has the characteristic that the original data can be recovered by receiving any sufficient number of valid encoded symbols, so that the receiving end does not need to receive all the fragmented data, but only needs to accumulate the number of valid fragmented data that reaches the decoding threshold to complete the decoding.

[0031] S2.2: Divide the encoded data stream into multiple independent discrete data segments. Each discrete data segment contains an independent data segment to be transmitted, a check bit, and a segment index.

[0032] In one specific embodiment, the transmitting end uniformly divides the data into segments of a preset fixed length (e.g., 26-bit or 52-bit), assigning each discrete segment a unique sequence number (i.e., segment index) and attaching a check bit. In other embodiments, the encoded data stream can also be segmented according to other rules; the specific segmentation rules are not limited here. In this embodiment, the check bit is a Cyclic Redundancy Check (CRC) code. The check bit for each discrete segment is formed by performing a CRC operation on the current discrete segment, and the check bit is appended to the end of the data segment to be transmitted. Since the data segments to be transmitted in each discrete segment contain different data, the corresponding check bits are also different, thereby achieving independent integrity verification of segment-level data segments and ensuring that there are no bit errors, tampering, or loss of data segments during transmission.

[0033] Specifically, during the transmission of discrete fragmented data, the sending end performs a CRC check on each discrete fragment, generating a unique check bit (CRC value) and appending it to the end of the data segment. Furthermore, each discrete fragment includes a fragment index, i.e., the number of the current discrete fragment, according to the segmentation order. This fragment index is sequentially numbered (0, 1, 2...) and encapsulated in the header of the fragmented data during segmentation at the sending end for identification and reassembly location.

[0034] This invention employs an asymmetric timeslot design between the transmitting and receiving ends. The transmitting end occupies a longer data transmission timeslot for continuously sending discrete fragmented data, while the receiving end occupies a shorter acknowledgment timeslot for centrally feeding back integrity verification results. This timeslot design isolates the data transmission process from the feedback acknowledgment process in time, allowing the transmitting end to continuously transmit in a streaming manner within its timeslot without waiting for packet-by-packet acknowledgment of individual fragments. Simultaneously, it ensures that the receiving end's selective retransmission requests can be reliably transmitted back in subsequent acknowledgment timeslots.

[0035] S2.3: Within the locked communication frequency, the transmitting end uses discrete fragmented data as the basic transmission unit and continuously sends it to the receiving end in a streaming mode.

[0036] Specifically, on the communication frequency locked in step S1, the transmitting end uses discrete fragmented data (including fragment index and CRC check bits) as the basic transmission unit and continuously transmits it within the available time window using a streaming transmission strategy until the window closes or the data transmission is complete. Streaming transmission means that the transmitting end does not wait for confirmation of individual discrete fragmented data, but continuously sends discrete fragmented data until the window closes or the data transmission is complete. This mechanism maximizes the utilization of burst window resources, avoids the pause overhead of the traditional "stop-and-wait-confirm" mode, and adapts to the burst channel characteristics of short windows and high randomness.

[0037] It should be noted that if the window for sending discrete fragment data has not been completed (e.g., 2ms remaining is insufficient to send a discrete fragment data), the unsent discrete fragment data can be stored in the sending buffer. When the next burst window arrives, the buffered fragment data will be sent first on the locked communication frequency point to avoid recalculating the already generated fragment data and improve transmission continuity.

[0038] S3: The receiving end performs integrity verification on each received discrete fragment data and requests the sending end to retransmit the current discrete fragment data if the verification fails.

[0039] In this step, the receiving end demodulates and verifies the integrity of each received discrete fragment data in real time. If the verification passes, the current discrete fragment data is determined to be valid and stored in the reassembly buffer set in the receiving end. If the verification fails, feedback information containing the index of the erroneous fragment is generated and sent to the sending end to request retransmission. The sending end dynamically adjusts the transmission queue according to the feedback information and retransmits the relevant discrete fragment data in the feedback information.

[0040] Specifically, the receiving end demodulates the received discrete data fragments one by one in real time, and then performs independent integrity checks (such as CRC checks) on each demodulated discrete data fragment. The receiving end performs independent checks on each fragment in real time, promptly detects errors and triggers retransmissions, making full use of the short window of time.

[0041] If the verification passes, the discrete fragment data is considered valid; if the verification fails, the receiver discards it, generates feedback information containing the index of the erroneous (or missing) fragment, and sends it to the sender to request retransmission. This feedback information is the retransmission information, which is a NACK or selective retransmission request, containing a list of indexes of failed / missing discrete fragment data. The sender dynamically adjusts the transmission queue based on the retransmission information from the receiver. If a retransmission request for a specific discrete fragment data is received, the discrete fragment data is retransmitted in the current window or a subsequent window.

[0042] S4: The receiving end recovers the original data by accumulating data across windows.

[0043] The receiving end counts the number of valid discrete fragment data accumulated in the reassembly buffer in real time. When the number of valid discrete fragment data reaches the preset decoding threshold, the data in the reassembly buffer is extracted, rearranged according to the fragment index, and RS decoding is performed. If the decoding is successful, the original data is restored and the transmission task is completed. If the decoding fails, the existing valid discrete fragment data is retained, and the receiver continues to wait for new valid discrete fragment data to be received to participate in the decoding until the decoding is successful.

[0044] In this step, the receiver recovers the original data by accumulating across windows. In other words, after a handshake is successful at a certain frequency, the transmission of subsequent discrete fragmented data can be carried out by accumulating across multiple independently occurring meteor trail windows, without requiring the transmission of all data to be completed within a single window.

[0045] In this embodiment, the receiving end is equipped with a reassembly buffer. Valid discrete fragment data that passed verification in step S3 is stored in this reassembly buffer, and a receiving status table is generated. Since each discrete fragment data is independent, the receiving end supports out-of-order reception and storage. That is, each discrete fragment data is stored in the reassembly buffer in the order of reception, without requiring index order; "logical sorting" is achieved through fragment indexes. For example, discrete fragment data with fragment index = 5 arrives before fragment index = 3, and can still be correctly stored and participate in subsequent sorting and reassembly. Subsequently, the receiving end continuously counts the number of valid discrete fragment data accumulated in the reassembly buffer. Specifically, each time a valid discrete fragment data is received, the corresponding accumulated number is immediately updated. When the accumulated valid discrete fragment data reaches a preset decoding threshold, reception is stopped and the decoding program is started. The receiving end extracts the data from the reassembly buffer, rearranges it according to the fragment index, and performs RS decoding to recover the original data, completing the transmission task. If decoding fails, the existing valid discrete fragment data is retained, and new valid discrete fragment data continues to accumulate until decoding is successful.

[0046] This embodiment, through the above mechanism, decomposes the traditional transmission task that can only be completed in a "long and stable" window into a process that can be discretely accumulated in multiple "short and weak" windows, thereby achieving extremely low-rate but highly reliable data transmission in the harsh meteor trail channel.

[0047] Example 2 Building upon Embodiment 1, this embodiment further provides a discrete fragmentation transmission system for under-dense meteor trail channels. The system includes a transmitter and a receiver. The transmitter establishes a communication link with the receiver using an active blind detection mechanism and locks the communication frequency. After establishing the communication link, the original data to be transmitted undergoes deletion and error correction encoding to generate an encoded data stream. This encoded data stream is then divided into multiple independent discrete fragments and transmitted in a preset order on the locked communication frequency. The receiver receives the discrete fragments and performs integrity verification on each received fragment. If verification fails, the receiver requests the transmitter to retransmit the current fragment. The receiver also recovers the original data through cross-window accumulation. The receiver includes a reassembly buffer to store valid discrete fragments that have passed verification.

[0048] Furthermore, the sending and receiving ends adopt an asymmetric time slot design. The sending end occupies the data transmission time slot to continuously send discrete fragment data in a streaming manner, while the receiving end occupies the acknowledgment time slot to centrally feed back the integrity verification results and retransmission requests to the sending end. When the communication window closes and data transmission is interrupted, the sending end continues to transmit the unfinished discrete fragment data directly in the subsequent window using the locked communication frequency point until decoding is successful.

[0049] The following simulation experiments further illustrate the system performance of the discrete fragmentation transmission method for under-dense meteor trail channels of the present invention.

[0050] Please see Figure 3 , Figure 3 This is a comparison of the cumulative distribution function (CDF) of data transmission under different fragmentation configurations for the discrete fragmentation transmission method proposed in this invention. FRAG26 (the curve with the circular marker) represents the implementation effect of using finer-grained (26-bit) fragmentation; FIX52 (the curve with the square marker) represents the implementation effect of using coarser-grained (52-bit) fragmentation. Figure 3 As can be seen, under the same channel model (Under-dense meteor-like echo (UAM) channel model) and signal-to-noise ratio conditions, the curve with FRAG26 configuration is always located to the upper left of the curve with FIX52 configuration. This indicates that the method of this invention has a higher probability of completing full data transmission when using a relatively smaller fragmentation granularity. This result strongly verifies the performance improvement effect of the core "discretization" idea of ​​this invention. Through comparison, it can be seen that fragmentation granularity is a key factor affecting transmission efficiency. Compared to the 52-bit fragmentation configuration, further dividing the data into smaller 26-bit fragments enables the system to more sensitively capture and utilize those "fragmented" windows that are extremely short-lived and insufficient to support larger fragments. This mechanism allows this invention to significantly reduce the waiting time for available windows by reducing the fragmentation granularity under extremely poor channel conditions, thereby effectively reducing the overall service transmission latency and eliminating the long-tail effect.

[0051] Please see Figure 4 , Figure 4 This is a trend analysis graph showing the relationship between the number of fragments and the system's receiving sensitivity in the discrete fragmentation transmission method proposed in this invention. The vertical axis represents the signal-to-noise ratio (SNR) required to achieve a 90% transmission success rate; a lower value indicates higher sensitivity (better performance). From... Figure 4As can be seen, as the same data packet is divided into more fragments (from 6 to 15), the required SNR threshold of the system exhibits a clear monotonic decreasing trend. This indicates that the smaller the fragments, the stronger the system's ability to utilize fragmented short windows, effectively reducing the channel SNR threshold required to complete transmission. By increasing the number of fragments (reducing the length of a single fragment), this invention reduces the requirements for channel signal-to-noise ratio, enabling the system to operate under weaker channel conditions, thereby indirectly extending the communication distance or improving availability in harsh environments.

[0052] Further, please see Figure 5 , Figure 5 This is a comparison of the packet loss rate (PLR) performance of the discrete fragmentation transmission method proposed in this invention under different fragmentation configurations and the traditional full-speed mode under different channel peak powers. The horizontal axis represents the peak power of the less dense channel. FRAG26 (curve with circular markers) indicates finer-grained (26-bit) fragmentation; FIX52 (curve with square markers) indicates coarser-grained (52-bit) fragmentation; and Traditional (curve with triangle markers) represents the traditional full-speed mode. Figure 5 It can be seen that in the traditional full-speed mode, the packet loss rate remains almost 100% (PLR=1) when the channel power is below -115dBm, indicating that the traditional whole-packet transmission method can hardly utilize the weak, sparse meteor trail channel. Although FIX52 performs better than the traditional mode, the packet loss rate is still as high as 60%-80% in the low-power range of -125dBm to -130dBm. The FRAG26 solution performs best across the full power range. Especially under the weak signal of -125dBm, the packet loss rate of this invention has been reduced to below 40%, significantly better than the 60% of the square-marked curve; near -115dBm, this invention is the first to achieve a low packet loss rate of below 10% (usable communication threshold).

[0053] Simulation results strongly demonstrate the robustness of this invention in low signal-to-noise ratio environments. Through the "discrete fragmentation" mechanism, this invention successfully "activates" weak channel regions (-135dBm to -115dBm) that are unusable by traditional technologies, greatly improving the utilization rate and transmission reliability of meteor trail channels.

[0054] This invention provides a low-overhead discrete fragmentation transmission method and system for bursty channels with weak meteor trails. Addressing the challenges of extremely short duration and weak gain in weak meteor trail channels, this invention employs a low-overhead blind probing mechanism to quickly establish a link. Redundant coding transforms the data to be transmitted into a coded data stream containing redundant information, which is then divided into multiple independent discrete fragments. Continuous transmission is implemented under the condition of randomly bursting weak meteor trail channels. At the receiving end, independent integrity checks and cross-window accumulation are performed on the received discrete fragments. When the number of valid fragments reaches a decoding threshold, the original data is decoded and recovered. This invention can significantly improve the utilization rate of weak weak meteor channels, effectively reduce communication system latency, and improve system reliability.

[0055] This invention significantly increases the probability of capturing a usable window in frequency-selective fading meteor trail channels by introducing a multi-frequency transmission and acquisition mechanism, reducing handshake waiting time. Combining streaming injection and feedback retransmission mechanisms, it maximizes data injection during the brief transparency period of the meteor trail channel and solves the problem of partial fragment loss through selective retransmission, achieving efficient breakpoint resumption. Utilizing the characteristics of redundant coding, the receiver can recover data even without receiving all original fragments (only requiring the decoding threshold to be reached), effectively shortening the delivery delay of long messages in intermittent channels. Therefore, addressing the characteristics of "short windows, random occurrence, and weak signals" in low-density meteor trail channels, this invention provides a reliable transmission method that can accumulate and transmit fragments piece by piece within sporadic weak windows, while possessing strong fault tolerance and breakpoint resumption capabilities.

[0056] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A discrete fragmentation transmission method for under-dense meteor trail channels, characterized in that, include: S1: The transmitting end uses an active blind detection mechanism to establish a communication link with the receiving end and lock the communication frequency point; S2: After establishing the communication link, the sending end performs deletion and error correction encoding on the original data to be transmitted to generate an encoded data stream, and divides the encoded data stream into multiple independent discrete data segments, which are then transmitted in a set order on a locked communication frequency. S3: The receiving end performs integrity verification on each received discrete fragment data and requests the sending end to retransmit the current discrete fragment data if the verification fails; S4: The receiving end recovers the original data by accumulating data across windows. The sending end and the receiving end adopt an asymmetric time slot design. The sending end occupies the data transmission time slot to continuously send the discrete fragment data in a streaming manner, and the receiving end occupies the acknowledgment time slot to centrally feed back the integrity verification results and retransmission requests to the sending end. When the communication window is closed, causing data transmission to be interrupted, the sending end continues to transmit the unfinished discrete fragment data directly in the subsequent window using the locked communication frequency point until decoding is successful.

2. The discrete fragmentation transmission method for under-dense meteor trail channels according to claim 1, characterized in that, S1 includes: S1.1: The transmitting end polls and transmits detection signals on multiple preset candidate frequency points; S1.2: After sending the detection signal, the transmitting end enters the monitoring state to wait for the response signal from the receiving end; S1.3: When the receiving end successfully captures the detection signal at the current candidate frequency point, the receiving end sends an acknowledgment signal to the transmitting end; S1.4: After receiving the response signal, the transmitting end locks the current candidate frequency point as the communication frequency point, completes the link handshake, and establishes a communication link.

3. The discrete fragmentation transmission method for under-dense meteor trail channels according to claim 1, characterized in that, S2 includes: S2.1: The sending end performs deletion and error correction encoding based on Reed-Solomon codes on the original data to be transmitted to generate an encoded data stream containing redundant information; S2.2: The encoded data stream is segmented to generate multiple independent discrete data segments, each of which contains an independent data segment to be transmitted, a check bit, and a segmentation index; S2.3: Within the locked communication frequency, the transmitting end uses the discrete fragmented data as the basic transmission unit and continuously transmits it to the receiving end in a streaming manner.

4. The discrete fragmentation transmission method for under-dense meteor trail channels according to claim 3, characterized in that, The check bit is a CRC cyclic redundancy check code. The check bit of each discrete data segment is formed by performing a CRC operation on the current discrete data segment, and the check bit is appended to the end of the data segment of the current discrete data segment.

5. The discrete fragmentation transmission method for under-dense meteor trail channels according to claim 3, characterized in that, S2.3 includes: The transmitting end uses the discrete fragment data as the basic transmission unit on the locked communication frequency point and continuously transmits it within the available time window using a streaming transmission strategy until the window closes or the data transmission is completed. The streaming transmission method means that the transmitting end does not wait for confirmation of individual discrete fragment data and continuously sends the discrete fragment data until the window closes or the data transmission is completed.

6. The discrete fragmentation transmission method for under-dense meteor trail channels according to claim 3, characterized in that, S3 includes: The receiving end demodulates and verifies the integrity of each received discrete fragment data in real time. If the verification passes, the current discrete fragment data is determined to be valid and the valid discrete fragment data is stored in the reassembly buffer set in the receiving end. If the verification fails, feedback information containing the error fragment index is generated and the feedback information is sent to the sending end to request retransmission. The sending end dynamically adjusts the sending queue based on the feedback information and retransmits the discrete fragment data related to the feedback information.

7. The discrete fragmentation transmission method for under-dense meteor trail channels according to claim 6, characterized in that, S4 includes: The receiving end continuously counts the number of valid discrete fragment data accumulated in the reassembly buffer. When the number of valid discrete fragment data reaches a preset decoding threshold, the data in the reassembly buffer is extracted, rearranged according to the fragment index, and RS decoding is performed. If the decoding is successful, the original data is restored and the transmission task is completed. If the decoding fails, the existing valid discrete fragment data is retained, and the receiver continues to wait for new valid discrete fragment data to be received to participate in the decoding until the decoding is successful.

8. A discrete fragmentation transmission system for under-dense meteor trail channels, characterized in that, The system includes a transmitter and a receiver, wherein... The transmitting end is used to establish a communication link with the receiving end using an active blind detection mechanism and lock the communication frequency point; after establishing the communication link, the original data to be transmitted is deleted, corrected, and encoded to generate an encoded data stream, and the encoded data stream is divided into multiple independent discrete fragments of data and transmitted on the locked communication frequency point in a preset order; The receiving end is used to receive discrete fragment data and perform integrity verification on each received discrete fragment data. If the verification fails, it requests the sending end to retransmit the current discrete fragment data. The receiving end is also used to recover the original data by accumulating across windows. The transmitting and receiving ends adopt an asymmetric time slot design. The transmitting end occupies the data transmission time slot to continuously transmit the discrete fragment data in a streaming manner. The receiving end occupies the acknowledgment time slot to centrally feed back the integrity verification results and retransmission requests to the transmitting end. When the communication window is closed, causing the data transmission to be interrupted, the transmitting end uses the locked communication frequency point in the subsequent window to directly continue transmitting the unfinished discrete fragment data until the decoding is successful.

9. The discrete fragmentation transmission system for under-dense meteor trail channels according to claim 8, characterized in that, The receiving end is equipped with a reassembly buffer, which is used to store valid discrete fragment data that has passed verification.

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