Near space large dynamic strong multipath communication access switching system

Abstract

The invention discloses a near space large dynamic strong multipath communication access switching system, which comprises a communication master node and communication slave nodes, the communication main node comprises a physical layer processing module, a trigger detection module, a rapid scheduling processing module, a smooth optimization processing module and an exit monitoring module. The communication slave node comprises a physical layer processing module and a control management module. According to the method, in deep space exploration activities such as the lunar surface, a large dynamic strong multipath scene is quickly and accurately identified through a trigger detection algorithm, and blind switching to a strong multipath resistant lowest rate gear is realized by adopting quick scheduling processing on the premise of confirming that an effective signal still meets the capability of a receiver; the problem of large communication waste caused by switching failure-return-switching re-failure in a traditional communication system protocol switching mechanism is solved.

Description

Technical Field

[0001] The invention discloses a near-space large dynamic strong multipath communication access switching system, and the method belongs to the field of near-space communication for deep space exploration. Background Art

[0002] In deep space exploration activities such as lunar exploration, there are usually large dynamic and strong multipath communication scenarios, which will cause severe jitter and changes in the communication link. In the traditional communication switching mechanism, the loss of bit synchronization can no longer truly reflect the rate change caused by the SPDU instruction, and the rate switching process continues to send SPDU and perform bit synchronization lock monitoring, resulting in a large waste of communication. Summary of the invention

[0003] The technical problem solved by the present invention is: to overcome the shortcomings of the prior art and propose a near-space large dynamic strong multipath communication access switching system, which solves the problem of large communication waste caused by switching failure-return-switching failure in the traditional communication system protocol switching mechanism, and achieves a significant improvement in communication efficiency in special application scenarios, thereby supporting the success of the mission to the greatest extent.

[0004] The technical solution of the present invention is: a near-space large dynamic strong multipath communication access switching system, comprising: a communication master node and a communication slave node; the communication master node comprises: a physical layer processing module, a trigger detection module, a fast scheduling processing module, a smooth optimization processing module and an exit monitoring module; the communication slave node comprises: a physical layer processing module and a control management module;

[0005] After the communication master node and the communication slave node are powered on and a full-duplex communication link is established, the detection module is triggered to receive the telemetry frame sent by the physical layer processing module, and the AGC and SNR are extracted from them. The actual receiving level value of the communication master node is calculated by the level marking algorithm, which is recorded as POW_N; POW_N is smoothed in units of the coherent integration time T_Coherent to obtain the smoothed receiving level data within the coherent integration time, which is recorded as POW_N_Coh. POW_N_Coh is calculated and processed by the link state detection algorithm to obtain the link state detection evaluation value. If the link state detection evaluation value is greater than the set threshold, the fast scheduling processing module is started;

[0006] After the fast scheduling processing module is started, it receives the telemetry frame sent by the physical layer processing module, extracts the carrier lock telemetry, Doppler frequency telemetry and receiving bit synchronization lock telemetry from it, and if the carrier lock telemetry is maintained in a locked state within the rated time period, and the Doppler frequency telemetry is maintained within a reasonable range, it sends a signal to the physical layer processing module to inform the communication slave node to switch the receiving and transmitting rates to the lowest gear specified in the protocol; after the signal is sent, the receiving and transmitting rates of the physical layer processing module are switched to the lowest gear specified in the protocol through remote control; after the receiving bit synchronization lock telemetry is re-locked, the smoothing optimization processing module is started;

[0007] After the smoothing optimization processing module is started, the telemetry frame sent by the physical layer processing module is received, and the AGC and SNR are extracted from it. The actual receiving level value of the communication main node is calculated through the level marking algorithm, which is recorded as POW_N`; when POW_N`<Threshold_low, it is considered that the multipath effect is obvious, and the relevant rate file under the minimum subcarrier spacing is selected; when Threshold_low≤POW_N`<Threshold_high, it is considered that the multipath effect is moderate, and the relevant rate file under the middle subcarrier spacing is selected; when POW_N`≥Threshold_high, it is considered that the multipath effect is Should be weak, select the relevant rate file under the maximum subcarrier spacing; after the rate file is determined, send a signal to the physical layer processing module to inform the communication slave node to switch the receiving and transmitting rates to the corresponding rate file, and after the signal is sent, switch the receiving and transmitting rates of the physical layer processing module to the corresponding rate file by remote control; if POW_N is greater than Threshold_high within the stable time T_sta, start to exit the monitoring module; the Threshold_low represents the receiving level decision threshold under the condition of obvious multipath effect, and Threshold_high represents the receiving level decision threshold under the condition of weak multipath effect;

[0008] After the exit monitoring module is started, it receives the telemetry frame sent by the physical layer processing module, extracts AGC and SNR from it, and calculates the actual receiving level value of the communication master node through the level marking algorithm, which is recorded as POW_N``; if the difference between adjacent POW_N`` is less than the normal jitter value POW_Delta of the multipath signal level, the exit count Quit_Num count value is increased by 1. If the difference between adjacent POW_N`` is greater than POW_Delta while Quit_Num is accumulated, Quit_Num is cleared and accumulated again. When the accumulated value of Quit_Num is greater than the exit count threshold Quit_Threshold, the exit monitoring module resets the smoothing optimization processing module, the fast scheduling processing module and the trigger detection module, and returns to the initial state.

[0009] The actual receiving level value of the communication main node is calculated through the level marking algorithm, including: transmitting the AGC-receiving level correspondence table and the SNR-receiving level correspondence table to the trigger detection module by pre-storing or on-track annotation, using AGC to mark the level in the interval of level value ≥-90dBm, and using SNR to mark the level in the interval of level value <-90dBm.

[0010] The specific process of selecting the value of the coherent integration time T_Coherent is as follows: if the environmental multipath and shielding effects are obvious, T_Coherent takes a value of 50ms to 100ms, otherwise T_Coherent takes a value of 300ms to 500ms.

[0011] The link status detection algorithm is used to calculate POW_N_Coh to obtain the link status detection evaluation value, including:

[0012] During the comparison time, if the difference between adjacent POW_N_Coh is greater than LossDelta1, then N num1 Accumulate 1; if the difference between adjacent POW_N_Coh is greater than LossDelta2, then N num2 Accumulate 1; if the difference between adjacent POW_N_Coh is greater than LossDelta3, then N num3 Accumulate 1; after the comparison time is over, perform weighted average on the obtained results, where the weight of LossDelta1 is recorded as Para1, the weight of LossDelta2 is recorded as Para2, and the weight of LossDelta3 is recorded as Para3, to obtain the link status detection evaluation value LossDelta1, LossDelta2, and LossDelta3 represent the threshold values ​​under relatively mild, normal, and severe level jitter conditions, respectively.

[0013] The 2LossDelta1≤LossDelta2≤3LossDelta1, 3LossDelta1≤LossDelta3≤5LossDelta1.

[0014] The 2Para1≤Para2≤3Para1, 3Para1≤Para3≤5Para1.

[0015] The set threshold is [1.5×Para1, 4×Para1].

[0016] The Doppler frequency telemetry is maintained within a reasonable range, which means that the reasonable range is a range where the amplitude variation does not exceed ±20% compared to the mean Doppler frequency.

[0017] The Threshold_high ≥ 1.8Threshold_low.

[0018] The relevant rate level under the minimum subcarrier spacing is specifically 15 kHz, the relevant rate level under the maximum subcarrier spacing is specifically 120 kHz, and the relevant rate level under the intermediate subcarrier spacing is specifically 60 kHz.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] (1) The present invention performs level marking based on AGC and SNR, and accurately predicts the actual receiving level value to the greatest extent possible.

[0021] (2) The present invention uses a blind switching mechanism to quickly establish communication under the conditions of minimum subcarrier spacing and the most reliable rate, avoiding repeated handshakes under the traditional communication mechanism and greatly improving communication efficiency.

[0022] (3) The present invention uses a smooth optimization processing mechanism to autonomously select waveforms with corresponding subcarrier spacing and rates under different degrees of multipath and obstruction conditions, thereby improving the communication rate while ensuring reliable communication.

[0023] (4) The present invention can be applied to deep space exploration represented by the moon, and embodies the design concept of optimal system, optimal efficiency, and optimal reliability in deep space exploration missions. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a principle block diagram of a communication access switching method for near-space large dynamic strong multipath; DETAILED DESCRIPTION

[0025] Combine the following Figure 1 The present invention is further described with reference to the accompanying drawings and specific embodiments.

[0026] The invention discloses a near-space large dynamic strong multipath communication access switching system, comprising: a communication master node and a communication slave node; the communication master node comprises: a physical layer processing module, a trigger detection module, a fast scheduling processing module, a smooth optimization processing module and an exit monitoring module; the communication slave node comprises: a physical layer processing module and a control management module.

[0027] After the communication master node and the communication slave node are powered on and a full-duplex communication link is established, the communication master node triggers the detection module to receive the telemetry frame sent by the physical layer processing module and extracts AGC and SNR from it. Since the level variation range of the multipath signal is very large, the trigger detection module requires the two parameters AGC and SNR to jointly evaluate the level state of the received signal. In the interval with higher level values, AGC is used to mark the level, and in the interval with lower level values, SNR is used to mark the level. The relevant parameters are implemented by pre-storage or on-orbit annotation. The marked level is recorded as POW_N. POW_N is smoothed in units of T_Coherent to obtain POW_N_Coh. T_Coherent has different values ​​in different multipath and obstruction scenarios. If the multipath and obstruction effects of the environment are obvious, T_Coherent takes a value of 50ms~100ms, otherwise T_Coherent takes a value of 300ms~500ms.

[0028] The trigger detection module then obtains the link status detection evaluation value through the following method. Specifically, within the comparison time, if the difference between adjacent POW_N_Coh is greater than LossDelta1, then N num1 Accumulate 1; if the difference between adjacent POW_N_Coh is greater than LossDelta2, then N num2 Accumulate 1; if the difference between adjacent POW_N_Coh is greater than LossDelta3, then N num3 Accumulate 1. After the comparison time is over, the obtained results are weighted averaged, where the weight of LossDelta1 is recorded as Para1, the weight of LossDelta2 is recorded as Para2, and the weight of LossDelta3 is recorded as Para3, and finally the link status detection evaluation value is obtained.

[0029]

[0030] Among them, the selection of each parameter generally follows the following rules: 2×LossDelta1≤LossDelta2≤3×LossDelta1, 3×LossDelta1≤LossDelta3≤5×LossDelta1, 2×Para1≤Para2≤3×Para1, 3×Para1≤Para3≤5×Para1.

[0031] If the link status detection evaluation value is greater than a preset threshold, the fast scheduling processing module is started, wherein the preset threshold is generally within the range of [1.5×Para1, 4×Para1].

[0032] After the fast dispatch processing module is started, it receives the telemetry frames sent by the physical layer processing module, extracts the carrier lock telemetry, Doppler frequency telemetry and receiving bit synchronization lock telemetry from it, and if the carrier lock telemetry is maintained in a locked state for 80% of the time period, and the Doppler frequency telemetry is maintained within a reasonable range (the amplitude change does not exceed ±20%), it sends a signal to the physical layer processing module to inform the communication slave node to switch the receiving and transmitting rates to the lowest gear specified in the protocol. After the signal is sent, the receiving and transmitting rates of its own physical layer processing module are switched to the lowest gear specified in the protocol through remote control. After the receiving bit synchronization lock telemetry is re-locked, the smooth optimization processing module is started.

[0033] After the smoothing optimization processing module is started, the telemetry frame sent by the physical layer processing module is received, and the AGC and SNR are extracted from it. The actual receiving level value is calculated by the level marking algorithm and recorded as POW_N. When POW_N<Threshold_low, it is considered that the multipath effect is obvious, and the relevant rate file with the minimum subcarrier spacing (for example, 15kHz) is selected; when Threshold_low≤POW_N<Threshold_high, it is considered that the multipath effect is moderate, and the relevant rate file with the intermediate subcarrier spacing (for example, 60kHz) is selected. When POW_N≥Threshold_high, it is considered that the multipath effect is weak, and the relevant rate file with a larger subcarrier spacing (for example, 120kHz) is selected. Threshold_high should generally be greater than 1.8×Threshold_low.

[0034] After the rate gear is determined, the smoothing optimization processing module sends a signal to the physical layer processing module, informing the communication slave node to switch the receiving and transmitting rates to the corresponding rate gear. After the signal is sent, the receiving and transmitting rates of its own physical layer processing module are switched to the corresponding rate gear through remote control. If POW_N is greater than Threshold_high within the stable time T_sta, the exit monitoring module is started.

[0035] After the exit monitoring module is started, it receives the telemetry frame sent by the physical layer processing module, extracts AGC and SNR from it, and calculates the actual receiving level value through the level marking algorithm, which is recorded as POW_N. If the difference between adjacent POW_N is less than POW_Delta (generally 6dB), the Quit_Num count value is increased by 1. If the difference between adjacent POW_N is greater than POW_Delta while Quit_Num is accumulated, Quit_Num is cleared and accumulated again. When the accumulated value of Quit_Num is greater than Quit_Threshold, the exit monitoring module resets the smoothing optimization processing module, the fast scheduling processing module and the trigger detection module, and returns to the initial state.

[0036] The present invention has been implemented and verified on the Chang'e-7 lander UHF transceiver and the lunar surface communication terminal of the manned lunar exploration lander. When the strong multipath and obstruction environment is simulated by the channel simulator, the method quickly identifies and performs blind switching, and then autonomously selects the waveform of the corresponding subcarrier spacing and rate under different degrees of multipath and obstruction conditions, thereby improving the communication rate while ensuring reliable communication. The invention has low complexity and flexible implementation, and can be widely used in deep space exploration represented by the moon, providing strong technical support for the establishment of efficient lunar near-space communications in the future, and has good technical and economic value.

[0037] Parts of the present invention that are not described in detail belong to the well-known technologies of those skilled in the art.

Claims

1. A near-space large dynamic strong multipath communication access switching system, characterized in that: include: Communication master node and communication slave node; The communication master node includes: a physical layer processing module, a trigger detection module, a fast scheduling processing module, a smooth optimization processing module and an exit monitoring module; the communication slave node includes: a physical layer processing module and a control management module; After the communication master node and the communication slave node are powered on and a full-duplex communication link is established, the detection module is triggered to receive the telemetry frame sent by the physical layer processing module, and the AGC and SNR are extracted from them. The actual receiving level value of the communication master node is calculated by the level marking algorithm, which is recorded as POW_N; POW_N is smoothed in units of the coherent integration time T_Coherent to obtain the smoothed receiving level data within the coherent integration time, which is recorded as POW_N_Coh. POW_N_Coh is calculated and processed by the link state detection algorithm to obtain the link state detection evaluation value. If the link state detection evaluation value is greater than the set threshold, the fast scheduling processing module is started; After the fast scheduling processing module is started, it receives the telemetry frame sent by the physical layer processing module, extracts the carrier lock telemetry, Doppler frequency telemetry and receiving bit synchronization lock telemetry from it, and if the carrier lock telemetry is maintained in a locked state within the rated time period, and the Doppler frequency telemetry is maintained within a reasonable range, it sends a signal to the physical layer processing module to inform the communication slave node to switch the receiving and transmitting rates to the lowest gear specified in the protocol; after the signal is sent, the receiving and transmitting rates of the physical layer processing module are switched to the lowest gear specified in the protocol through remote control; after the receiving bit synchronization lock telemetry is re-locked, the smoothing optimization processing module is started; After the smoothing optimization processing module is started, the telemetry frame sent by the physical layer processing module is received, and the AGC and SNR are extracted from it. The actual receiving level value of the communication main node is calculated through the level marking algorithm, which is recorded as POW_N`; when POW_N`<Threshold_low, it is considered that the multipath effect is obvious, and the relevant rate file under the minimum subcarrier spacing is selected; when Threshold_low≤POW_N`<Threshold_high, it is considered that the multipath effect is moderate, and the relevant rate file under the middle subcarrier spacing is selected; when POW_N`≥Threshold_high, it is considered that the multipath effect is Should be weak, select the relevant rate file under the maximum subcarrier spacing; after the rate file is determined, send a signal to the physical layer processing module to inform the communication slave node to switch the receiving and transmitting rates to the corresponding rate file, and after the signal is sent, switch the receiving and transmitting rates of the physical layer processing module to the corresponding rate file by remote control; if POW_N is greater than Threshold_high within the stable time T_sta, start to exit the monitoring module; the Threshold_low represents the receiving level decision threshold under the condition of obvious multipath effect, and Threshold_high represents the receiving level decision threshold under the condition of weak multipath effect; After the exit monitoring module is started, it receives the telemetry frame sent by the physical layer processing module, extracts AGC and SNR from it, and calculates the actual receiving level value of the communication master node through the level marking algorithm, which is recorded as POW_N``; if the difference between adjacent POW_N`` is less than the normal jitter value POW_Delta of the multipath signal level, the exit count Quit_Num count value is increased by 1. If the difference between adjacent POW_N`` is greater than POW_Delta while Quit_Num is accumulated, Quit_Num is cleared and accumulated again. When the accumulated value of Quit_Num is greater than the exit count threshold Quit_Threshold, the exit monitoring module resets the smoothing optimization processing module, the fast scheduling processing module and the trigger detection module, and returns to the initial state.

2. According to claim 1, a near-space large dynamic strong multipath communication access switching method is characterized by: The actual receiving level value of the communication main node is calculated through the level marking algorithm, including: transmitting the AGC-receiving level correspondence table and the SNR-receiving level correspondence table to the trigger detection module by pre-storing or on-track annotation, using AGC to mark the level in the interval of level value ≥-90dBm, and using SNR to mark the level in the interval of level value <-90dBm.

3. According to claim 1, a near-space large dynamic strong multipath communication access switching method is characterized by: The specific process of selecting the value of the coherent integration time T_Coherent is as follows: if the environmental multipath and shielding effects are obvious, T_Coherent takes a value of 50ms to 100ms, otherwise T_Coherent takes a value of 300ms to 500ms.

4. According to claim 1, a near-space large dynamic strong multipath communication access switching method is characterized by: The link status detection algorithm is used to calculate POW_N_Coh to obtain the link status detection evaluation value, including: During the comparison time, if the difference between adjacent POW_N_Coh is greater than LossDelta1, then N num1 Accumulate 1; if the difference between adjacent POW_N_Coh is greater than LossDelta2, then N num2 Accumulate 1; if the difference between adjacent POW_N_Coh is greater than LossDelta3, then N num3 Accumulate 1; after the comparison time is over, perform weighted average on the obtained results, where the weight of LossDelta1 is recorded as Para1, the weight of LossDelta2 is recorded as Para2, and the weight of LossDelta3 is recorded as Para3, to obtain the link status detection evaluation value LossDelta1, LossDelta2, and LossDelta3 represent the threshold values ​​under relatively mild, normal, and severe level jitter conditions, respectively.

5. The autonomous recovery system based on special link fault characteristic evaluation according to claim 4, characterized in that: The 2LossDelta1≤LossDelta2≤3LossDelta1, 3LossDelta1≤LossDelta3≤5LossDelta1.

6. The autonomous recovery system based on special link fault characteristic evaluation according to claim 4, characterized in that: The 2Para1≤Para2≤3Para1, 3Para1≤Para3≤5Para1.

7. The autonomous recovery system based on special link fault characteristic evaluation according to claim 4, characterized in that: The set threshold is [1.5×Para1, 4×Para1].

8. The autonomous recovery system based on special link fault characteristic evaluation according to claim 1, characterized in that: The Doppler frequency telemetry is maintained within a reasonable range, which means that the reasonable range is a range where the amplitude variation does not exceed ±20% compared to the mean Doppler frequency.

9. The autonomous recovery system based on special link fault characteristic evaluation according to claim 1, characterized in that: The Threshold_high≥1.8Threshold_loW.

10. The autonomous recovery system based on special link fault characteristic evaluation according to claim 1, characterized in that: The relevant rate file under the minimum subcarrier spacing is specifically 15kHz; the relevant rate file under the maximum subcarrier spacing is specifically 120kHz z ; The relevant rate file under the intermediate subcarrier spacing is specifically 60kH z .

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