A communication method and system for removing frequency hopping interference using a pseudo-random sequence

Abstract

The application discloses a communication method and system for removing frequency hopping interference by using pseudo-random sequences. A first pseudo-random sequence code is added to a first data symbol at a sending end to form a data frame for sending; a second pseudo-random sequence code and a second data symbol are extracted from the data frame at a receiving end; error code degree checking is performed on the second pseudo-random sequence code based on the first pseudo-random sequence code; interference preliminary detection is performed based on a PN peak value of the second pseudo-random sequence code, and interference accurate measurement is performed based on the PN peak energy; a PN peak energy average value when there is no interference is used as an energy threshold value, and the second data symbol is subjected to interference removal processing according to the relationship between the PN peak energy of the second pseudo-random sequence code and the energy threshold value. The application can quickly detect the error code rate and the interference, can improve the accuracy of interference removal in specific applications, and can dynamically adjust the energy threshold value to be suitable for different interference environments.

Description

Technical Field

[0001] This invention relates to the field of frequency hopping communication, and in particular to a communication method and system for removing frequency hopping interference using pseudo-random sequences. Background Technology

[0002] In communication systems, interference removal refers to the process of eliminating or reducing interference in a signal through specific algorithms and techniques, thereby improving signal quality and reliability. Interference is usually caused by other equipment or environmental factors, such as other communication equipment on the radio frequency band, noise on power lines, weather, and malicious frequency interference, etc.

[0003] Frequency-hopping communication systems are widely used in mobile wireless communication systems for real-time communication in complex electromagnetic environments. This is because they offer high bandwidth utilization, enabling efficient data transmission and effectively avoiding frequency scanning interference. However, frequency-hopping communication systems are also susceptible to interference from malicious frequency points, and eliminating this interference can further improve the reliability of wireless communication. Summary of the Invention

[0004] The purpose of this invention is to provide a communication method and system that uses pseudo-random sequences to remove frequency hopping interference, thereby reducing interference in frequency hopping communication and achieving more reliable wireless communication, addressing all or part of the problems mentioned above.

[0005] The technical solution adopted in this invention is as follows:

[0006] A communication method for removing frequency hopping interference using pseudo-random sequences, comprising:

[0007] At the sending end, a first pseudo-random sequence code is added before the first data symbol to form a data frame for transmission.

[0008] The receiving end receives data frames and extracts the second pseudo-random sequence code and the second data symbol from them;

[0009] The second pseudo-random sequence code is verified based on the first pseudo-random sequence code;

[0010] Interference detection is performed based on the PN peak value and PN peak energy of the second pseudo-random sequence code;

[0011] Based on a predetermined energy threshold, the second data symbol is subjected to interference removal processing according to the relationship between the PN peak energy of the second pseudo-random sequence code and the energy threshold.

[0012] Furthermore, the step of verifying the second pseudo-random sequence code based on the first pseudo-random sequence code includes:

[0013] The bit error rate of the second pseudo-random sequence code is calculated based on the first pseudo-random sequence code.

[0014] Furthermore, the method for calculating the bit error rate is as follows:

[0015]

[0016] Where i represents the sign bit, C1[] represents the correlation peak output, and Np represents the length of the pseudo-random sequence code. Let represent the second pseudo-random sequence code, y[n] represent the baseband signal, and sign() represent the sign bit operation. * This indicates the conjugate operation.

[0017] Furthermore, the interference detection based on the PN peak value and PN peak energy of the second pseudo-random sequence code includes:

[0018] Calculate the PN peak value of the second pseudo-random sequence code;

[0019] When the difference between the PN peak value of the second pseudo-random sequence code and the length of the first pseudo-random sequence code exceeds a first threshold, the presence of interference that needs to be removed is detected based on the relationship between the PN peak energy of the second pseudo-random sequence code and the second threshold value.

[0020] Furthermore, the method of detecting the presence of interference that needs to be removed based on the relationship between the PN peak energy of the second pseudo-random sequence code and the second threshold includes:

[0021] When the PN peak energy of the second pseudo-random sequence code is less than twice the second threshold, it is determined that there is no interference that needs to be removed; when the PN peak energy of the second pseudo-random sequence code reaches or exceeds twice the second threshold, it is determined that there is interference that needs to be removed.

[0022] Furthermore, when the PN peak energy of the second pseudo-random sequence code is less than the second threshold, it is determined that there is no interference; when the PN peak energy of the second pseudo-random sequence code is between the second threshold and twice the second threshold, it is determined that there is negligible interference.

[0023] Furthermore, the predetermined energy threshold is the average energy of the PN peak of the effective pulse.

[0024] Furthermore, the effective pulse is the pulse when the PN peak value of the second pseudo-random sequence code is equal to the length of the first pseudo-random sequence code.

[0025] Furthermore, the step of removing interference from the second data symbol based on the relationship between the PN peak energy of the second pseudo-random sequence code and the energy threshold includes:

[0026] If the PN peak energy of the second pseudo-random sequence code is lower than the energy threshold, then all data symbols are retained;

[0027] If the PN peak energy of the second pseudo-random sequence code is between two and four times the energy threshold, then the data symbol is set to one-quarter of the current data symbol.

[0028] If the PN peak energy of the second pseudo-random sequence code is greater than four times the energy threshold, then the data symbol is set to zero.

[0029] To address all or some of the aforementioned problems, the present invention also provides a communication system for removing frequency hopping interference using pseudo-random sequences, wherein the system executes the aforementioned communication method for removing frequency hopping interference using pseudo-random sequences.

[0030] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0031] 1. This invention uses pseudo-random sequence codes (PN codes) for interference detection and removal, which can effectively remove malicious frequency interference. By taking advantage of the similarity between data symbols and PN codes in terms of interference, the error rate and interference can be detected quickly.

[0032] 2. This invention can dynamically adjust the relevant threshold and use the relationship between the PN peak value and PN peak energy and the relevant threshold to detect and remove interference, which can improve the accuracy of interference removal in specific applications. Attached Figure Description

[0033] The present invention will be described by way of example and with reference to the accompanying drawings, wherein:

[0034] Figure 1 This is a schematic diagram of the transmission frame structure.

[0035] Figure 2 This is a flowchart of the interference removal process.

[0036] Figure 3 This is the BER performance graph under 10% frequency interference.

[0037] Figure 4 This is the BER performance graph under 30% frequency interference.

[0038] Figure 5 This is the BER performance graph under 50% frequency interference. Detailed Implementation

[0039] All features disclosed in this specification, or all steps in all disclosed methods or processes, may be combined in any way, except for mutually exclusive features and / or steps.

[0040] Any feature disclosed in this specification (including any appended claims and abstract) may be replaced by other equivalent or similar features, unless specifically stated otherwise. That is, unless specifically stated otherwise, each feature is merely one example of a series of equivalent or similar features.

[0041] This invention proposes a communication technique for removing frequency hopping interference based on pseudo-random sequence codes, using QPSK modulation as a foundation. In wireless communication, the data signal (data symbols) received by the receiver is subject to frequency hopping blocking interference after synchronization. To remove this interference and better restore the data, this invention uses a pseudo-random sequence code (PN code) prepended to the data bits. Based on the characteristic that the PN code and data symbols are susceptible to environmental interference to similar degrees, the data symbols are processed at the receiving end by judging the interference of the PN code. Since these data symbols and the PN code are similarly susceptible to interference, the data symbols in the same frame are processed by comparing the PN code at the receiving end with the PN code at the transmitting end. This, to a certain extent, removes the interference caused by frequency hopping and improves the reliability of the communication system.

[0042] Example 1

[0043] A communication method for removing frequency hopping interference using pseudo-random sequences, the method comprising the following steps:

[0044] Step 1: Add a PN code (pseudo-random sequence code) to the sending end.

[0045] like Figure 1 As shown, at the transmitting end, a PN code composed of M pseudo-random codes (i.e., the first PN code) is added before N data symbols (i.e., the first data symbols) to form a complete data frame for transmission. Each hop (i.e., one data frame) is a pulse. The data frame can be encapsulated using a certain protocol for easy transmission and reception. Before sending the data frame, the data symbols can be encrypted or compressed to increase the security and efficiency of transmission.

[0046] Step 2: The receiving end extracts the PN code.

[0047] The receiving end receives data frames. After receiving the data frames, it performs decapsulation and decompression or other processing on the data frames to extract the PN code (i.e., the second PN code) and data symbols (i.e., the second data symbols).

[0048] Step 3, PN code verification.

[0049] The PN code at the receiving end is verified based on the PN code at the transmitting end. This verification involves correlating the received PN code with the local PN code at the transmitting end (i.e., the same PN code in the same data frame) to calculate the PN peak value, thereby determining the bit error rate of data transmission. y[n] represents the baseband signal, n = 0, 1, 2, ..., N-1. The correlator uses the locally generated PN code sequence and the input signal to perform conjugate correlation accumulation. Therefore, the formula for the output of the correlation function is:

[0050]

[0051] Where i represents the sign bit, C1 represents the correlation peak output, and Np represents the length (in bits) of the pseudo-random sequence code. This represents the second pseudo-random sequence code, and sign() represents the sign bit operation. * This indicates the conjugate operation.

[0052] Step 4, Interference Detection. The presence of interference can cause discrepancies in the received PN code, thus affecting its accuracy. This step detects interference based on the PN peak value and PN peak energy of the received PN code. The detection process includes:

[0053] Calculate the PN peak value of the PN code received at the receiver. In the received PN code, the position of the PN peak is fixed, and the PN peak value can be detected using correlation algorithms, such as cross-correlation algorithms.

[0054] When the difference between the PN peak value of the PN code at the receiving end and the length (M) of the PN code at the transmitting end exceeds the first threshold, the presence of interference that needs to be removed is detected based on the relationship between the PN peak energy of the second pseudo-random sequence code and the second threshold.

[0055] For example, when the PN peak value of the PN code at the receiving end is inconsistent with or differs significantly from the expected PN peak value (i.e., the first threshold), it indicates the presence of interference. The expected PN peak value is, for example, M. If the PN peak value is M, the signal is considered to be of good quality. If the PN peak value is less than M, the PN peak energy is used to determine whether there is interference that needs to be removed.

[0056] For data symbols with a PN peak value less than M, the presence of interference that needs to be removed is determined by calculating the PN peak energy of the PN code at the receiver. The formula for calculating the PN peak energy is:

[0057]

[0058] Where E is the PN peak energy of a certain hop (taken from 0 to X-1, where X is the hop frequency), I(n) is the PN data of the I path, Q(n) is the PN data of the Q path, and M is the PN code length in a hop.

[0059] If the PN peak energy value is below a certain value, the data frame can be considered uninterrupted; otherwise, interference may exist. To better determine whether interference exists, a threshold for the PN peak energy can be set. In this invention, this threshold is referred to as the second threshold. When the PN peak energy is less than twice the second threshold, it indicates that the interference of the current data symbol is small or negligible and does not need to be removed. This involves classifying the degree of interference: when the PN peak energy is less than the second threshold, it is considered that there is no interference; when the PN peak energy is between the second threshold and twice the second threshold, it is considered that interference exists but is negligible. Furthermore, if the PN peak energy is greater than twice the second threshold, in this embodiment, it is considered that there is interference that needs to be removed.

[0060] Step 5, Interference Removal. This step, based on a predetermined energy threshold, removes interference from the data symbols at the receiving end according to the relationship between the PN peak energy of the PN code at the receiving end and this energy threshold. The removal process is as follows: Figure 2 As shown.

[0061] For the communication process of this invention, if the PN peak value of the PN code at the receiving end is M, the communication quality is considered to be relatively good, and the pulse at this time is valid. The average PN peak energy of the valid pulse is calculated using the following formula:

[0062]

[0063] Where E1 is the average energy of X hops, X is the number of hops, and E(i) is the PN peak energy of the i-th hop.

[0064] Then, based on the relationship between the PN peak energy of the PN code at the receiving end and the energy threshold, the data symbols at the receiving end are subjected to interference removal processing as follows:

[0065] For a superior signal, the PN peak energy should have a small difference from E1. If the current PN peak energy is found to be below the average, it indicates that the current data interference is small, and all data should be retained. If the PN peak energy of the current receiver's PN code is between two and four times the energy threshold, the data symbol is set to one-quarter of the current data symbol; if it is greater than four times the energy threshold, the data symbol is set to zero. This method of data processing can achieve a better goal of removing interference. In addition, in this invention, the simulation parameters can be adjusted multiple times based on the simulation results before calculating the PN peak energy of the receiver's PN code.

[0066] Example 2

[0067] This embodiment discloses a communication system for removing frequency hopping interference using pseudo-random sequences. The system executes the communication method for removing frequency hopping interference using pseudo-random sequences described in Embodiment 1. Specifically, the system includes a transmitter and a receiver. The receiver includes a data receiving module, a verification module, an interference detection module, and an interference removal module, wherein:

[0068] The sending end is configured to add a PN code (i.e., a first pseudo-random sequence code) before sending the first data symbol to form a data frame, and then encapsulate it using the corresponding communication protocol. Similarly, the first data symbol can be encrypted or compressed before encapsulation.

[0069] The data receiving module is configured to receive data frames and extract the PN code (i.e., the second pseudo-random sequence code) and the second data symbol.

[0070] The verification module is configured to verify the PN code extracted by the data receiving module based on the PN code of the transmitting end. The specific verification process and method can be found in step 3 of Example 1, and will not be repeated here.

[0071] The interference detection module is configured to perform interference detection based on the PN peak value and PN peak energy of the PN code extracted by the data receiving module. Similarly, the specific interference detection process and method can be found in step 4 of Embodiment 1, and will not be repeated here.

[0072] The interference removal module is configured to: based on a predetermined energy threshold, and according to the relationship between the PN peak energy of the PN code extracted by the data receiving module and the energy threshold, perform interference removal processing on the second data symbol extracted by the data receiving module. The specific method for setting the energy threshold and the interference removal process can be found in step 5 of Embodiment 1, and will not be repeated here.

[0073] Example 3

[0074] This embodiment simulates and tests the performance of the communication technology designed in this invention to demonstrate its superiority.

[0075] First, this embodiment uses the simulation parameters in Table 1 below to perform 3000 simulations in a single-input single-output (SISO) system, obtaining the bit error rate performance with and without the interference removal algorithm under three levels of interference. EbN0 is the sensitivity, and BER (Bit Error Rate) is the bit error rate.

[0076]

[0077]

[0078] Table 1 Simulation Parameters

[0079] From the appendix Figure 3 It can be seen that adding the interference removal algorithm of this invention results in a significant performance improvement under 10% frequency interference. In an interference environment, 10% of frequency data is lost; by removing interference through the algorithm, the impact of frequency interference on BER is effectively reduced.

[0080] From the appendix Figure 4 It can be seen that adding the interference removal algorithm still results in a significant performance improvement even with 30% frequency interference. When the frequency interference increases, the BER increases significantly, causing a greater loss of sensitivity, and there is a significant difference between not adding the algorithm and adding the algorithm.

[0081] Depend on Figure 5 As can be seen, the addition of the interference removal algorithm significantly improves performance under 50% frequency interference conditions. The simulation results above demonstrate that the method proposed in this invention can adapt to different interference environments, and the interference removal algorithm effectively improves bit error rate performance.

[0082] This invention is not limited to the specific embodiments described above. The invention extends to any new feature or combination disclosed in this specification, as well as any new method or process step or combination disclosed herein.

Claims

1. A communication method for removing frequency hopping interference using pseudo-random sequences, characterized in that, include: At the sending end, a first pseudo-random sequence code is added before the first data symbol to form a data frame for transmission. The receiving end receives data frames and extracts the second pseudo-random sequence code and the second data symbol from them; The second pseudo-random sequence code is verified based on the first pseudo-random sequence code; Interference detection is performed based on the PN peak value and PN peak energy of the second pseudo-random sequence code; Based on a predetermined energy threshold, the second data symbol is subjected to interference removal processing according to the relationship between the PN peak energy of the second pseudo-random sequence code and the energy threshold.

2. The communication method for removing frequency hopping interference using pseudo-random sequences as described in claim 1, characterized in that, The step of verifying the second pseudo-random sequence code based on the first pseudo-random sequence code includes: The bit error rate of the second pseudo-random sequence code is calculated based on the first pseudo-random sequence code.

3. The communication method for removing frequency hopping interference using pseudo-random sequences as described in claim 2, characterized in that, The method for calculating the bit error rate is as follows: Where i represents the sign bit, C1[] represents the correlation peak output, and Np represents the length of the pseudo-random sequence code. Indicates the second pseudo-random sequence code. Let y[n] represent the i-th symbol of the second pseudo-random sequence code, y[n+i] represent the baseband signal, y[n+i] represent the i-th symbol of the baseband signal, and sign() represent the sign bit operation. This indicates the conjugate operation.

4. The communication method for removing frequency hopping interference using pseudo-random sequences as described in claim 1, characterized in that, The interference detection based on the PN peak value and PN peak energy of the second pseudo-random sequence code includes: Calculate the PN peak value of the second pseudo-random sequence code; When the difference between the PN peak value of the second pseudo-random sequence code and the length of the first pseudo-random sequence code exceeds a first threshold, the presence of interference that needs to be removed is detected based on the relationship between the PN peak energy of the second pseudo-random sequence code and the second threshold value.

5. The communication method for removing frequency hopping interference using pseudo-random sequences as described in claim 4, characterized in that, The method of detecting the presence of interference that needs to be removed based on the relationship between the PN peak energy of the second pseudo-random sequence code and the second threshold includes: When the PN peak energy of the second pseudo-random sequence code is less than twice the second threshold, it is determined that there is no interference that needs to be removed; when the PN peak energy of the second pseudo-random sequence code reaches or exceeds twice the second threshold, it is determined that there is interference that needs to be removed.

6. The communication method for removing frequency hopping interference using pseudo-random sequences as described in claim 5, characterized in that, When the PN peak energy of the second pseudo-random sequence code is less than the second threshold, it is determined that there is no interference; when the PN peak energy of the second pseudo-random sequence code is between the second threshold and twice the second threshold, it is determined that there is negligible interference.

7. The communication method for removing frequency hopping interference using pseudo-random sequences as described in claim 1, characterized in that, The predetermined energy threshold is the average energy of the PN peak of the effective pulse.

8. The communication method for removing frequency hopping interference using pseudo-random sequences as described in claim 7, characterized in that, The effective pulse is the pulse when the PN peak value of the second pseudo-random sequence code is equal to the length of the first pseudo-random sequence code.

9. The communication method for removing frequency hopping interference using pseudo-random sequences as described in claim 7, characterized in that, The step of removing interference from the second data symbol based on the relationship between the PN peak energy of the second pseudo-random sequence code and the energy threshold includes: If the PN peak energy of the second pseudo-random sequence code is lower than the energy threshold, then all data symbols are retained; If the PN peak energy of the second pseudo-random sequence code is between two and four times the energy threshold, then the data symbol is set to one-quarter of the current data symbol. If the PN peak energy of the second pseudo-random sequence code is greater than four times the energy threshold, then the data symbol is set to zero.

10. A communication system that utilizes pseudo-random sequences to remove frequency hopping interference, characterized in that, The system includes a transmitter and a receiver; The transmitting end is configured to add a first pseudo-random sequence code before transmitting the first data symbol to form a data frame; The receiving end includes a data receiving module, a verification module, an interference detection module, and an interference removal module, wherein: The data receiving module is configured to: receive data frames and extract the second pseudo-random sequence code and the second data symbol therein; The verification module is configured to verify the second pseudo-random sequence code based on the first pseudo-random sequence code; The interference detection module is configured to perform interference detection based on the PN peak value and PN peak energy of the second pseudo-random sequence code; The interference removal module is configured to: perform interference removal processing on the second data symbol based on a predetermined energy threshold and according to the relationship between the PN peak energy of the second pseudo-random sequence code and the energy threshold.

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