Reliable synchronization method of variable spread spectrum ratio signal

Abstract

According to the reliable synchronization method for the variable spread spectrum ratio signal, the main thought is that the period of an input carrier tracking loop is synchronized to the lowest symbol rate in an energy accumulation mode, so that it is guaranteed that the update rate of the loop is always a stationary value, rate indication information carried by the UWR is analyzed through a unique word detection module, and the UWR is synchronized to the minimum symbol rate. And the symbol energy accumulation module performs energy accumulation according to the rate indication information, synchronizes the de-spreading symbols at different rates to the lowest symbol rate, and sends the de-spreading symbols to a carrier tracking loop.

Description

Technical Field

[0001] This invention belongs to the field of communication technology and proposes a reliable synchronization method for variable spread spectrum ratio signals to address the limitations of real-time synchronization difficulties in synchronization technology in digital communication systems. Background Technology

[0002] Spread spectrum communication is an information transmission method where the bandwidth occupied by the signal is much larger than the minimum bandwidth required to transmit the information. Bandwidth expansion is achieved through an independent code sequence, using encoding and modulation methods, independent of the transmitted information data. At the receiving end, the same code is used for correlation synchronization reception, despreading, and recovery of the transmitted information data. This allows the signal to be transmitted at a relatively low signal-to-noise ratio. The spreading ratio is an important indicator of a spread spectrum signal; a larger spreading ratio results in higher spreading gain and stronger anti-interference capabilities, but it also reduces the channel rate. The optimal approach is to adjust the spreading ratio in real time according to channel quality, maximizing channel bandwidth utilization while maintaining anti-interference capabilities. However, adjusting the spreading ratio causes continuous changes in the signal symbol rate, which in turn causes continuous changes in the update rate of the synchronization tracking loop, leading to a decrease in tracking quality or even signal lock-off. Therefore, maintaining the stability of the tracking loop during continuous symbol rate changes is a key issue in variable spread ratio signal demodulation.

[0003] In the synchronization process of variable spread spectrum ratio signals, the integration period of the integrator module changes continuously with the symbol rate due to the constantly changing spread spectrum ratio. In traditional spread spectrum demodulation, the despread symbols are typically fed into the carrier loop according to the integration period. However, the carrier tracking loop is implemented by a loop filter, which is essentially a continuously smooth convergence process. Its loop update period should be a stable process. If the loop update period is constantly switched, it will disrupt the stability of the loop filter's operation, leading to loop lockout. Summary of the Invention

[0004] This invention uses energy accumulation to synchronize the period of the input carrier tracking loop to the lowest symbol rate, thereby ensuring that the loop update rate is always a stable value.

[0005] To achieve the above effects, this invention provides a reliable synchronization method for a variable spread ratio signal for spread spectrum signal processing. The spread spectrum signal includes a synchronization header (CW), a rate indicator word (UWR), and a transmission payload (MLOAD). The method is characterized in that the spread spectrum signal is input into the carrier NCO and then integrated. When calculating the integration period and processing the despreading symbols, a unique word detection is used to parse the rate indicator information carried by the UWR. Then, the symbol energy is accumulated according to the rate indicator information to synchronize the despreading symbols of different rates to the lowest symbol rate and send them to the carrier tracking loop.

[0006] Preferably, the aforementioned synchronization header CW is used for signal acquisition, and the rate indicator word UWR is used to indicate the spreading ratio of the subsequent MLOAD section.

[0007] This invention provides a reliable synchronization method for a variable spreading ratio signal, specifically including: Step 1: Unique word detection. The channel unique words UWI and UWQ will send the most significant bits of the demodulated data I and Q branches to the shift register. Each channel is connected to UWI, UWQ, and... and Perform matching detection, and based on the detection results, perform phase ambiguity correction and subsequent rate analysis; Step 2: Energy accumulation. The despread symbols are expanded by the sign bit. Before accumulation, the despread symbols are XORed according to the sign bit and then accumulated. Step 3: Carrier synchronization. After symbol expansion, the signal data from different carrier channels are demodulated, and the symbol bits are XORed and then processed. The data is then accumulated and selected separately. One channel is accumulated and then selected, which is synchronized with the other channel that is directly selected.

[0008] Preferably, the aforementioned channel unique words UWI and UWQ are small m-sequences of 63 bits in length.

[0009] Preferably, in the above steps, the most significant bit of a pair of I branches is sent to a shift register, along with UWI, UWQ, and Matching detection is performed, and the results are processed to generate reverse and forward pulses. These are then concentrated into the I-channel reverse detection and phase selection pulses enter the selector. Phase ambiguity correction and subsequent rate analysis are then performed to obtain phase-ambiguity-free I-channel data.

[0010] Preferably, in the above steps, the most significant bit of a pair of Q branches is sent to a shift register, along with UWI, UWQ, and Matching detection is performed, and the detection results are processed to generate reverse and forward pulses. After being concentrated into the Q-channel reverse detection, phase selection pulses are entered into the selector, and then phase ambiguity correction and subsequent rate analysis are performed to obtain phase-ambiguity-free Q-channel data.

[0011] Preferably, the I and Q branches are ORed and then cross-processed to form a reset pulse and a cross pulse. The reset pulse enters the selector through the IQ cross-detection and the cross-selection pulse. The cross pulse is ORed to form a detection pulse and then cross-detected to form a unique character detection flag.

[0012] Preferably, in step three above, sign extension processing is performed on the data I and Q branches respectively. The I and Q branches are 17 bits each, which become 18 bits after sign extension. After processing, the data of the I and Q branches are demodulated and the sign bits are extracted. The sign bits of the data I branch and the Q branch are XORed, and the sign bits of the data Q branch and the I branch are XORed. The result of the two XORs is 19 bits, which is then accumulated and processed for data selection.

[0013] This invention provides a system for implementing the above-described reliable synchronization method for variable spread ratio signals, comprising a unique word detection module, an energy accumulation module, and a carrier synchronization module, wherein... The unique word detection module sends the channel unique words UWI and UWQ to the most significant bits of the demodulated data I and Q branches to the shift register. Each channel is connected to UWI, UWQ, and UWQ. and Perform matching detection, and based on the detection results, perform phase ambiguity correction and subsequent rate analysis; The energy accumulation module performs sign bit expansion on the despread symbols and XORs the despread symbols according to the sign bits before accumulation. The carrier synchronization module performs symbol expansion on the signal data of different carrier channels, demodulates the data, XORs the symbol bits, and then performs accumulation and data selection processing on each channel. One channel is accumulated and then selected for data selection, achieving synchronization with the other channel which is directly selected for data selection.

[0014] The present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the above-described method.

[0015] In the synchronization process of variable spread ratio signals, the integration period of the integrator module changes continuously with the symbol rate due to the constantly changing spread ratio. In traditional spread spectrum demodulation, the despread symbols are usually fed into the carrier loop according to the integration period. However, the carrier tracking loop is implemented by a loop filter, which is essentially a continuously smooth convergence process. Its loop update period should be a stable process. If the loop update period is constantly switched, it will disrupt the stability of the loop filter, leading to loop lockout. This invention proposes a reliable synchronization method for variable spread ratio signals. The main idea is to synchronize the period of the input carrier tracking loop to the lowest symbol rate by accumulating energy, thereby ensuring that the loop update rate is always a stable value. When the signal spread ratio gradually decreases from 8 times to 4 times and then to 2 times, the symbol energy output by the integrator module is accumulated during non-loop tracking time. During loop tracking time, the accumulated energy is sent to the tracking loop value and the accumulator is cleared. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments of the present invention will be briefly introduced below. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A schematic diagram of the carrier signal format structure of the variable spread ratio signal of the present invention is shown; Figure 2 A basic flowchart of the reliable synchronization method for variable spread ratio signals of the present invention is shown; Figure 3 A schematic diagram of an embodiment of the reliable synchronization method for variable spread ratio signals of the present invention is shown; Figure 4 A schematic diagram of signal energy accumulation is shown in the reliable synchronization method for variable spread ratio signals of the present invention; Figure 5 A schematic diagram of the carrier tracking loop for the reliable synchronization method of the variable spread ratio signal of the present invention is shown; Figure 6 A schematic diagram of the unique word detection method for the reliable synchronization method of variable spread ratio signals of the present invention is shown; Figure 7 A schematic diagram of the energy accumulation process of the reliable synchronization method for variable spread ratio signals of the present invention is shown; Figure 8 A schematic diagram of the carrier synchronization principle framework of the reliable synchronization method for variable spread ratio signals of the present invention is shown. Detailed Implementation

[0018] The features and exemplary embodiments of various aspects of the present invention will now be described in detail. To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only configured to explain the present invention and are not configured to limit the present invention. For those skilled in the art, the present invention can be practiced without some of these specific details. The following description of the embodiments is merely intended to provide a better understanding of the present invention by illustrating examples of the invention.

[0019] It should be noted that in this invention, 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 thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element.

[0020] An embodiment of the reliable synchronization method for variable spread ratio signals proposed in this invention.

[0021] like Figure 1 As shown, the specific signal format is as follows, where CW is the synchronization header, used for signal acquisition; UWR is the rate indicator word, indicating the spreading ratio of the subsequent MLOAD section; and MLOAD is the transmitted information payload.

[0022] like Figure 2 As shown, during the synchronization process of a variable spreading ratio signal, the integration period of the integrator module changes continuously with the symbol rate due to the constantly changing spreading ratio. In traditional spread spectrum demodulation, the despread symbols are typically fed into the carrier loop according to the integration period. However, the carrier tracking loop is implemented by a loop filter, which is essentially a continuously smooth convergence process. Its loop update period should be a stable process. If the loop update period is constantly switched, it will disrupt the stability of the loop filter's operation, leading to loop lockout.

[0023] This invention provides an embodiment of a reliable synchronization method for a variable spread ratio signal, used for spread spectrum signal processing. The spread spectrum signal includes a synchronization header (CW), a rate indicator word (UWR), and a transmitted information payload (MLOAD). The method is characterized in that the spread spectrum signal is input into the carrier NCO and integrated. When calculating the integration period and processing despreading symbols, unique word detection is used to parse the rate indicator information carried by the UWR. Then, symbol energy accumulation is performed according to the rate indicator information to synchronize despreading symbols of different rates to the lowest symbol rate and send them to the carrier tracking loop.

[0024] In some embodiments, the synchronization header (CW) is used for signal acquisition, and the rate indicator word (UWR) is used to indicate the spreading ratio of the subsequent MLOAD portion.

[0025] like Figure 3As shown, this invention provides an embodiment of a reliable synchronization method for a variable spread ratio signal, specifically including: Step 1: Unique word detection. The channel unique words UWI and UWQ will send the most significant bits of the demodulated data I and Q branches to the shift register. Each channel is connected to UWI, UWQ, and... and Perform matching detection, and based on the detection results, perform phase ambiguity correction and subsequent rate analysis; Step 2, Energy Accumulation: Before accumulating the energy, the despread symbols are XORed based on the sign bits. Step 3: Carrier synchronization. After symbol expansion, the signal data from different carrier channels are demodulated, and the symbol bits are XORed and then processed. The data is then accumulated and selected separately. One channel is accumulated and then selected, which is synchronized with the other channel that is directly selected.

[0026] In some embodiments, the channel unique words UWI and UWQ are small m-sequences of 63 bits in length.

[0027] In some embodiments, step one sends the most significant bit of the I branch to a shift register, along with UWI, UWQ, and Matching detection is performed, and the results are processed to generate reverse and forward pulses. These are then concentrated into the I-channel reverse detection and phase selection pulses enter the selector. Phase ambiguity correction and subsequent rate analysis are then performed to obtain phase-ambiguity-free I-channel data.

[0028] In some embodiments, step one sends the most significant bit of the Q branch to a shift register, along with UWI, UWQ, and Matching detection is performed, and the detection results are processed to generate reverse and forward pulses. After being concentrated into the Q-channel reverse detection, phase selection pulses are entered into the selector, and then phase ambiguity correction and subsequent rate analysis are performed to obtain phase-ambiguity-free Q-channel data.

[0029] In some embodiments, the I and Q branches are ORed and then cross-processed to form a reset pulse and a cross pulse. The reset pulse enters the selector through the IQ cross-detection and the cross-selection pulse. The cross pulse is ORed to form a detection pulse and then cross-detected to form a unique character detection flag.

[0030] In some embodiments, step three performs sign extension processing on the data I and Q branches respectively. The I and Q branches are 17 bits each, which become 18 bits after sign extension. After processing, the data of the I and Q branches are demodulated and the sign bits are extracted. The sign bits of the data I branch and the Q branch are XORed, and the sign bits of the data Q branch and the I branch are XORed. The result of the two XORs is 19 bits, which is then accumulated and processed for data selection.

[0031] This invention provides a system embodiment for a reliable synchronization method for up-variable spread ratio signals, comprising a unique word detection module, an energy accumulation module, and a carrier synchronization module, wherein... The unique word detection module sends the channel unique words UWI and UWQ to the most significant bits of the demodulated data I and Q branches to the shift register. Each channel is connected to UWI, UWQ, and UWQ. and Perform matching detection, and based on the detection results, perform phase ambiguity correction and subsequent rate analysis; The energy accumulation module performs sign bit expansion on the despread symbols and XORs the despread symbols according to the sign bits before accumulation. The carrier synchronization module performs symbol expansion on the signal data of different carrier channels, demodulates the data, XORs the symbol bits, and then performs accumulation and data selection processing on each channel. One channel is accumulated and then selected for data selection, achieving synchronization with the other channel which is directly selected for data selection.

[0032] like Figure 4 As shown in the figure, an embodiment of a reliable synchronization method for a variable spread ratio signal provided by the present invention synchronizes the period of the input carrier tracking loop to the lowest symbol rate through energy accumulation, thereby ensuring that the loop update rate is always a stable value. As shown in the figure below, when the signal spread ratio gradually decreases from 8 times to 4 times and then to 2 times, the symbol energy output by the integration module is accumulated during the non-loop tracking time, and the accumulated energy is sent to the tracking loop value and the accumulator is cleared during the loop update time.

[0033] In the specific implementation process, such as Figure 5 As shown, the rate indication information carried by the UWR needs to be parsed by the unique word detection module. The symbol energy accumulation module accumulates energy according to the rate indication information, synchronizes the despread symbols of different rates to the lowest symbol rate, and sends them to the carrier tracking loop.

[0034] This invention provides an embodiment of a reliable synchronization method for a variable spread spectrum ratio signal, comprising: (1) Unique character detection like Figure 6As shown, the channel unique words UWI and UWQ are 63-bit little m sequences. The most significant bits of the demodulated data I and Q branches are sent to a shift register. Each channel is associated with UWI, UWQ, and... and Matching detection is performed, and phase ambiguity correction and subsequent rate analysis are carried out based on the detection results.

[0035] The most significant bit of the I branch is sent to the shift register, along with UWI, UWQ, and Matching detection is performed, and the results are processed to generate reverse and forward pulses. These are then concentrated into the I-channel reverse detection and phase selection pulses enter the selector. Phase ambiguity correction and subsequent rate analysis are then performed to obtain phase-ambiguity-free I-channel data.

[0036] The most significant bit of the Q branch is sent to the shift register, along with UWI, UWQ, and Matching detection is performed, and the detection results are processed to generate reverse and forward pulses. After being concentrated into the Q-channel reverse detection, phase selection pulses are entered into the selector, and then phase ambiguity correction and subsequent rate analysis are performed to obtain phase-ambiguity-free Q-channel data.

[0037] After the I and Q branches are ORed, they are then cross-processed to form a reset pulse and a cross pulse. The reset pulse passes through the IQ cross detection and enters the selector through the cross selection pulse. The cross pulse is ORed to form a detection pulse, which is then passed through the unique character detection to form a unique character detection flag.

[0038] (2) Energy accumulation like Figure 7 As shown, the energy accumulation module is designed as follows. Since the despread symbols are subject to data modulation, the despread symbols need to be XORed with the symbol bits before accumulation.

[0039] (3) Carrier synchronization like Figure 8 As shown, the signal data from different carrier channels are symbol-spread, demodulated, and then XORed with the symbol bits. After further processing, they are accumulated and selected separately. One path undergoes accumulation before data selection, achieving synchronization with the other path's direct data selection. For the data I and Q branches, symbol spreading is performed separately. The I and Q branches are each 17 bits, which becomes 18 bits after symbol spreading. After processing, the I and Q branch data are demodulated and the symbol bits are extracted. The symbol bits of the I and Q branches are XORed, and the symbol bits of the Q and I branches are XORed. The resulting 19 bits are then accumulated and selected.

[0040] The present invention also provides an embodiment of a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the above-described method.

[0041] This invention proposes a reliable synchronization method for variable spread ratio signals. The main idea is to synchronize the period of the input carrier tracking loop to the lowest symbol rate through energy accumulation, thereby ensuring that the loop update rate remains stable. As the signal spread ratio gradually decreases from 8 times to 4 times and then to 2 times, the symbol energy output by the integrator is accumulated during non-loop tracking time. During loop tracking time, the accumulated energy is sent to the tracking loop value and the accumulator is cleared.

[0042] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0043] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0044] The above description is merely an embodiment of this application and is not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A reliable synchronization method for a variable spreading ratio signal, used for spread spectrum signal processing, wherein the spread spectrum signal includes a synchronization header (CW), a rate indicator word (UWR), and a transmitted information payload (MLOAD), characterized in that... The method inputs the spread spectrum signal into the carrier NCO and performs integration calculation. When calculating the integration period and processing the despreading symbols, unique word detection is used to parse the rate indication information carried by the UWR. Then, the energy is accumulated according to the rate indication information through symbol energy accumulation. The despreading symbols of different rates are synchronized to the lowest symbol rate and sent to the carrier tracking loop.

2. The reliable synchronization method for a variable spread spectrum ratio signal according to claim 1, characterized in that: The synchronization header (CW) is used for signal acquisition, and the rate indicator word (UWR) is used to indicate the spreading ratio of the subsequent MLOAD section.

3. The reliable synchronization method for a variable spread ratio signal according to claim 1 or 2, characterized in that... The method specifically includes: Step 1: Unique word detection. The channel unique words UWI and UWQ will send the most significant bits of the demodulated data I and Q branches to the shift register. Each channel is connected to UWI, UWQ, and... and Perform matching detection, and based on the detection results, perform phase ambiguity correction and subsequent rate analysis; Step 2, Energy Accumulation: Before accumulating the energy, the despread symbols are XORed based on the sign bits. Step 3: Carrier synchronization. After symbol expansion, the signal data from different carrier channels are demodulated, and the symbol bits are XORed and then processed. The data is then accumulated and selected separately. One channel is accumulated and then selected, which is synchronized with the other channel that is directly selected.

4. The reliable synchronization method for a variable spread ratio signal according to claim 3, characterized in that... The channel unique words UWI and UWQ are small m-sequences of 63 bits in length.

5. The reliable synchronization method for a variable spread ratio signal according to claim 3, characterized in that, The step described above sends the highest bit of one I branch to the shift register, along with UWI, UWQ, and Matching detection is performed, and the results are processed to generate reverse and forward pulses. These are then concentrated into the I-channel reverse detection and phase selection pulses enter the selector. Phase ambiguity correction and subsequent rate analysis are then performed to obtain phase-ambiguity-free I-channel data.

6. The reliable synchronization method for a variable spread ratio signal according to claim 3, characterized in that... The step described above sends the highest bit of a pair of Q branches to a shift register, along with UWI, UWQ, and Matching detection is performed, and the detection results are processed to generate reverse and forward pulses. After being concentrated into the Q-channel reverse detection, phase selection pulses are entered into the selector, and then phase ambiguity correction and subsequent rate analysis are performed to obtain phase-ambiguity-free Q-channel data.

7. The reliable synchronization method for a variable spread ratio signal according to claim 5 or 6, characterized in that... The I and Q branches are ORed and then cross-processed to form a reset pulse and a cross pulse. The reset pulse enters the selector through the IQ cross-detection and the cross-selection pulse. The cross pulse is ORed to form a detection pulse and then cross-detection to form a unique character detection flag.

8. The reliable synchronization method for a variable spread ratio signal according to claim 3, characterized in that, In step three, sign extension is performed on the data I and Q branches respectively. The I and Q branches are 17 bits each, which becomes 18 bits after sign extension. After processing, the data of the I and Q branches are demodulated and the sign bits are extracted. The sign bits of the data I branch and the Q branch are XORed, and the sign bits of the data Q branch and the I branch are XORed. The result of the two XORs is 19 bits, which is then accumulated and processed for data selection.

9. A system for implementing a reliable synchronization method for a variable spread ratio signal according to any one of claims 1-8, comprising a unique word detection module, an energy accumulation module, and a carrier synchronization module, characterized in that: The unique word detection module sends the channel unique words UWI and UWQ to the most significant bits of the demodulated data I and Q branches to the shift register. Each channel is connected to UWI, UWQ, and UWQ. and Perform matching detection, and based on the detection results, perform phase ambiguity correction and subsequent rate analysis; The energy accumulation module performs sign bit expansion on the despread symbols and XORs the despread symbols according to the sign bits before accumulation. The carrier synchronization module performs symbol expansion on the signal data of different carrier channels, demodulates the data, XORs the symbol bits, and then performs accumulation and data selection processing on each channel. One channel is accumulated and then selected for data selection, achieving synchronization with the other channel which is directly selected for data selection.

10. A computer-readable storage medium having a computer program stored thereon that, when executed by a processor, implements the method of any one of claims 1-8.

Images