Satellite communication transmission method and device

Abstract

The application relates to a satellite communication transmission method and device. The method of the application is applied to a sending end and comprises the following steps: encoding source data, and framing the coded output data based on an agreed subframe structure; performing symbol mapping processing on the framed output subframes to generate a first baseband signal; performing pulse shaping processing to obtain a second baseband signal; performing up-conversion and digital-to-analog conversion processing on the baseband signal to obtain an analog signal meeting the emission frequency point requirement and the sampling rate requirement, and performing emission; the subframe structure comprises a frame header synchronization sequence, a characteristic sequence used for carrying modulation mode information and coding mode information, a data load sequence and a frame tail synchronization sequence; the frame header synchronization sequence, the characteristic sequence, the data load sequence and the frame tail synchronization sequence are arranged in sequence, and the end of each sequence is sequentially inserted with a symbol pilot, and each symbol pilot constitutes a unique word sequence used for realizing a preset function. The application is beneficial to improving communication stability.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of satellite communication, and particularly relates to a satellite communication transmission method and device. BACKGROUND

[0002] The transmission technology protocol and standard in satellite communication are core technologies, which determine the flexibility, stability and communication efficiency of the related communication system. Most of the current satellite communication systems define their transmission technology protocol and standard by the manufacturers themselves, and some manufacturers use the DVB-S or DVB-S2 / X broadcast communication standard. The related technology protocols and standards are not unified. The transmission technology protocol and standard in the prior art have serious constraints in the flexibility, stability and expansibility of transmission, and cannot well meet the actual application.

[0003] The above content is only used to assist in understanding the technical solutions of the application, and does not represent the acknowledgement of the above content as prior art. SUMMARY

[0004] In order to at least overcome the problems in the related art, the application provides a satellite communication transmission method and device, which communicates based on a specific physical layer transmission technology format, so as to avoid the problems in the prior art to some extent.

[0005] In order to achieve the above purpose, the application adopts the following technical solutions:

[0006] In a first aspect,

[0007] The application provides a satellite communication transmission method, applied to a sending end, which comprises the following steps:

[0008] Encoding the source data, and framing the encoded output data based on an agreed subframe structure;

[0009] Performing symbol mapping processing on the framed output subframe to generate a first baseband signal;

[0010] Performing pulse shaping processing on the first baseband signal to obtain a second baseband signal with improved inter-symbol interference;

[0011] Performing up-conversion and digital-to-analog conversion processing on the second baseband signal to obtain an analog signal that meets the requirements of the transmission frequency point and the sampling rate, and performing signal transmission;

[0012] The subframe structure comprises a frame header synchronization sequence, a feature sequence for carrying modulation mode information and encoding mode information, a data payload sequence for carrying valid data information, and a frame tail synchronization sequence.

[0013] The frame header synchronization sequence, the feature sequence, the data payload sequence and the frame tail synchronization sequence are sequentially arranged, and a symbol pilot is sequentially inserted at the end of each sequence, and each symbol pilot constitutes a unique word sequence for realizing a preset function.

[0014] Optionally, a total of 8448 symbols are included in the subframe structure.

[0015] In the subframe structure, the frame header synchronization sequence, the feature sequence, the data payload sequence and the frame tail synchronization sequence are sequentially arranged, and a symbol pilot is sequentially inserted at the end of each sequence, and each symbol pilot constitutes a unique word sequence for realizing a preset function.

[0016] The number of the frame header synchronization sequences is 2, and the first frame header synchronization sequence and the second frame header synchronization sequence are sequentially arranged; the number of the feature sequences is 1; the number of the data payload sequences is 128; and the number of the frame tail synchronization sequences is 1.

[0017] The symbol length of the first frame header synchronization sequence, the second frame header synchronization sequence, the feature sequence, the data payload sequence and the frame tail synchronization sequence is 63 symbols.

[0018] The first frame header synchronization sequence, the second frame header synchronization sequence, the feature sequence and the frame tail synchronization sequence are all binary sequences, and in the communication process, each binary sequence is configured to be equivalent to its reverse sequence.

[0019] Optionally, in the process of encoding the source data, the encoding mode is LDPC encoding.

[0020] The frame header synchronization sequence, the feature sequence, the frame tail synchronization sequence and the unique word sequence are all generated by BPSK modulation.

[0021] The data payload sequence is generated by one or more of BPSK, QPSK, 8PSK, 16APSK and 16QAM modulation.

[0022] Optionally, the pulse shaping processing mode includes:

[0023] The first baseband signal is zero-padded and interpolated, and the zero-padded and interpolated baseband signal is filtered through a root-raised cosine filter to obtain the second baseband signal.

[0024] In a second aspect,

[0025] The application provides a satellite communication transmission method, applied to a receiving end, and the method includes:

[0026] The received analog signal is down-converted and subjected to analog-digital conversion processing to obtain a baseband digital signal.

[0027] The baseband digital signal is subjected to matching filtering processing corresponding to the pulse shaping processing of the transmitting end.

[0028] Based on the agreed subframe structure, frame positioning is performed on the intermediate signal obtained by the matched filtering processing to achieve frame synchronization;

[0029] On the basis of frame synchronization, demodulation and decoding processing are performed on the intermediate signal based on the modulation mode information and the encoding mode information carried in the subframe to obtain the effective data transmitted;

[0030] The subframe structure includes: a frame header synchronization sequence, a feature sequence for carrying modulation mode information and encoding mode information, a data payload sequence for carrying effective data information, and a frame tail synchronization sequence

[0031] In the subframe structure, the frame header synchronization sequence, the feature sequence, the data payload sequence, and the frame tail synchronization sequence are arranged in sequence, and a symbol pilot is inserted at the end of each sequence in sequence, and each symbol pilot constitutes a unique word sequence for implementing a preset function.

[0032] Optionally, there are a total of 8448 symbols in the subframe structure;

[0033] Among them:

[0034] The number of frame header synchronization sequences is 2, which are a first frame header synchronization sequence and a second frame header synchronization sequence in sequence; the number of feature sequences is 1; the number of data payload sequences is 128; and the number of frame tail synchronization sequences is 1;

[0035] The symbol length of the first frame header synchronization sequence, the second frame header synchronization sequence, the feature sequence, the data payload sequence, and the frame tail synchronization sequence is 63 symbols;

[0036] The first frame header synchronization sequence, the second frame header synchronization sequence, the feature sequence, and the frame tail synchronization sequence are all binary sequences, and in the communication process, each binary sequence is configured to be equivalent to its reverse sequence.

[0037] Optionally, the encoding mode information includes LDPC encoding rate information;

[0038] The frame header synchronization sequence, the feature sequence, the frame tail synchronization sequence, and the unique word sequence are all generated by BPSK modulation;

[0039] The symbols in the data payload sequence are generated by one or more of the BPSK, QPSK, 8PSK, 16APSK, and 16QAM modulation methods.

[0040] Optionally, in the process of implementing frame synchronization, it includes:

[0041] The local storage of the first frame header synchronization sequence and intermediate signals is correlated, and the captured subframe is determined based on the correlation value.

[0042] Then, the locally stored second frame header synchronization sequence and the received signal are used for related processing to achieve frame synchronization.

[0043] Thirdly,

[0044] This application provides a satellite communication transmission device that uses the method described above for transmitting data processing and signal transmission at the transmitting end.

[0045] Fourthly,

[0046] This application provides a satellite communication transmission device that uses the method described above for receiving signals and processing received data at the receiving end.

[0047] The application employs the above technical solution and has at least the following beneficial effects:

[0048] In the technical solution of this application, a pre-defined subframe structure is adopted during satellite communication. This subframe structure contains a distributed unique word sequence. In the event of sudden interference, the continuous sequence may be interfered with. At this time, based on the specific configuration, the unique word sequence can be used to realize preset functions, such as using the unique word sequence to perform frame synchronization and carry modulation and encoding information, thereby improving the stability of communication.

[0049] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from an examination of the following, or may be learned from the practice of the invention. Attached Figure Description

[0050] The accompanying drawings are used to provide a further understanding of the technical solutions of this application or the prior art, and constitute a part of the specification. The drawings illustrating embodiments of this application, together with the embodiments of this application, are used to explain the technical solutions of this application, but do not constitute a limitation on the technical solutions of this application.

[0051] Figure 1 This is a schematic diagram illustrating the data flow of a satellite communication transmission method provided in one embodiment of this application.

[0052] Figure 2 This is a schematic diagram illustrating the subframe structure in one embodiment of this application;

[0053] Figure 3 This is a schematic illustration of the constellation mapping involved in the modulation process in one embodiment of this application. Figure 1 ;

[0054] Figure 4 An illustration of constellation mapping involved in modulation in an embodiment of the present application Figure 2 . DETAILED DESCRIPTION

[0055] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be described in detail below. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of the present application.

[0056] As described in the background, most of the current satellite communication systems are defined by the manufacturers themselves with transmission technology protocols and standards. The transmission technology protocols and standards in the prior art have serious constraints in flexibility, stability and scalability, and cannot better meet the actual application.

[0057] For example, in the application scenarios of VSAT satellite communication or high-throughput satellite communication, in order to meet the actual application, it is necessary to solve the problems of compatibility of narrowband and wideband, smooth communication of high-order modulation and low-order modulation, arbitrary switching between different coding and decoding, subsequent flexible upgrade and expansion, etc.

[0058] Based on this, the present application proposes a satellite communication transmission scheme, which communicates based on a specific physical layer transmission technology format, to a certain extent to avoid the problems in the prior art.

[0059] In an embodiment, the satellite communication transmission method proposed by the present application is applied to a sending end (such as a satellite terminal), and the method includes: Figure 1 The upper half of the figure shows that the method includes:

[0060] Encoding the source data and framing the encoded output data based on an agreed subframe structure (corresponding to the encoding and framing link in the figure) Figure 1

[0061] Specifically, for example, in the process of encoding the source data, the encoding mode is LDPC encoding (Low-density Parity-check), and then the LDPC encoder output is composed into a complete subframe (or physical frame) based on the agreed subframe structure. The agreed subframe structure is the focus of the present application, which will be described in detail below:

[0062] As shown in the figure Figure 2 ​As shown, the subframe structure includes: a frame header synchronization sequence, a characteristic sequence for carrying modulation mode information and encoding mode information, a data payload sequence for carrying valid data information, a frame tail synchronization sequence;

[0063] In the subframe structure, the frame header synchronization sequence, the characteristic sequence, the data payload sequence and the frame tail synchronization sequence are arranged in sequence, and a symbol pilot is inserted at the end of each sequence in sequence Figure 2 The symbol pilots constitute a unique word sequence for implementing a preset function.

[0064] The symbol pilot is generally used for frequency tracking, but in this application, the dispersed unique word sequence based on the symbol pilot can implement other preset functions. Specifically, in practice, in the case of burst interference, the continuous sequence may be disturbed, and the dispersed unique word sequence is provided in the subframe structure, and at this time, the unique word sequence can be used to implement the preset function based on the specific configuration, such as using the unique word sequence to perform frame synchronization and carry modulation mode information and encoding mode information, thereby achieving the effect of improving communication stability.

[0065] As a specific implementation, in practice, the characteristic sequence can be changed frame by frame, that is, the so-called variable coding modulation mode is implemented.

[0066] As a specific implementation, in this embodiment,

[0067] The number of frame header synchronization sequences is 2, which are a first frame header synchronization sequence and a second frame header synchronization sequence in sequence; the number of characteristic sequences is 1; the number of data payload sequences is 128 (or, one subframe contains 128 data blocks for transmitting data information); the number of frame tail synchronization sequences is 1;

[0068] The symbol length of the first frame header synchronization sequence, the second frame header synchronization sequence, the characteristic sequence, the data payload sequence and the frame tail synchronization sequence is 63 symbols, in other words, the 132 symbols of the unique word sequence are added in one subframe structure, and one subframe has 8448 symbols in total;

[0069] In this embodiment, the first frame header synchronization sequence, the second frame header synchronization sequence, the characteristic sequence and the frame tail synchronization sequence are all binary sequences, and in the communication process, each binary sequence is configured to be equal to the original sequence with its reverse sequence.

[0070] In this mode, the subframe adopts a fixed frame length, is suitable for continuous communication and burst communication mode, and is particularly suitable for a time division multi-address (a plurality of users share a frequency band in time slots) scenario with multiple users; and in this frame structure, the transmission efficiency is about 8064 / 8448 x % = 95% in terms of the number of symbols, and the transmission efficiency is also good; and from the perspective of information transmission, it is easy to understand that, in the case of a fixed symbol rate, the information rate is not the same in the case of different modulation modes and code rates, and the corresponding transmission rate is also different; and regarding the preset function of the unique word sequence, in the case of burst interference, the first 63 symbols of the UW sequence (unique word sequence) can be used as a synchronization word sequence, and the last 63 symbols can be used as a characteristic sequence.

[0071] As a specific embodiment, in this embodiment, the related sequence is configured as,

[0072] In the first frame header synchronization sequence, the first symbol is "1", the second symbol is "1", the third symbol is "0", and then the 60th symbol is "0", the 62nd symbol is "1", and the 63rd symbol is "1";

[0073] In the second frame header synchronization sequence, the first symbol is "0", the second symbol is "0", the third symbol is "0", and then the 60th symbol is "1", the 62nd symbol is "0", and the 63rd symbol is "0";

[0074] In the frame tail synchronization sequence, the first symbol is "1", the second symbol is "0", the third symbol is "0", and then the 60th symbol is "1", the 62nd symbol is "1", and the 63rd symbol is "0";

[0075] Without considering the variable coding modulation mode, the unique word sequence can be a fixed symbol sequence.

[0076] In addition, it should be noted that in this embodiment, the frame header synchronization sequence (including the first and second frame header synchronization sequences), the characteristic sequence, the frame tail synchronization sequence, and the unique word sequence are all generated by BPSK modulation;

[0077] The data payload sequence is generated by one or more of the BPSK, QPSK, 8PSK, 16APSK, and 16QAM modulation modes;

[0078] Correspondingly, it is easy to understand that, Figure 1The frame structure shown, in the source data encoding, adopts (8064, k) LDPC encoding, k is the length of the uncoded data, determined by the code rate, unit is bit, fixed output 8064 bits; The LDPC encoding block required by each physical frame is determined by the modulation mode of the data part, BPSK is 1 block, QPSK is 2 blocks, 8PSK is 3 blocks, 16APSK and 16QAM are 4 blocks.

[0079] Continuing to Figure 1 , after the framing link, the subframes output by the framing are processed by symbol mapping to generate a first baseband signal (corresponding to the symbol mapping link in Figure 1 );

[0080] In the symbol mapping link, corresponding to the difference in the modulation mode mentioned in the foregoing, the application adopts a corresponding constellation mapping mode, as shown in Figure 3 and Figure 4 .

[0081] Continuing to Figure 1 , after the symbol mapping link, the first baseband signal is processed by pulse shaping to obtain a second baseband signal with improved inter-symbol interference (corresponding to the pulse shaping link in Figure 1 );

[0082] Specifically, the pulse shaping processing mode adopted in this embodiment is: the first baseband signal is zero-padded and interpolated, and the baseband signal after zero-padding and interpolation is passed through a root-raised cosine filter to obtain the second baseband signal. After this processing, the second baseband signal has a smoother time-domain waveform and a smaller frequency-domain occupation width compared with the first baseband signal.

[0083] Finally, the second baseband signal is processed by frequency up-conversion and digital-to-analog conversion to obtain an analog signal that meets the requirements of the transmission frequency point and the sampling rate (corresponding to the frequency up-conversion and DAC link in Figure 1 ), and signal transmission, this link is similar to the prior art, and will not be further described here.

[0084] The technical scheme of the application will be described below from the receiving end, as shown in the lower half of Figure 1 , in an embodiment, the satellite communication transmission method proposed by the application is applied to the receiving end, and the method comprises:

[0085] The received analog signal is processed by analog-to-digital conversion and frequency down-conversion to obtain a baseband digital signal (corresponding to the ADC and frequency down-conversion link in Figure 1 );

[0086] The baseband digital signal is processed by matching filtering corresponding to the pulse shaping processing at the transmitting end (corresponding to the matching filtering link in Figure 1 ), to highlight the signal features;

[0087] Based on the agreed subframe structure (see the relevant content of the transmitting end part in the foregoing), frame positioning is performed on the intermediate signal obtained through the matched filtering processing, so as to realize frame synchronization;

[0088] Specifically, in the process of realizing frame synchronization, the following steps are included:

[0089] The first frame header synchronization sequence stored locally (referring to the local of the receiving end) is correlated with the intermediate signal, and the subframe is determined according to the correlation value, that is, the coarse synchronization of the physical frame is realized; and the second frame header synchronization sequence stored locally is correlated with the received signal, so as to realize frame synchronization, that is, the fine synchronization of the physical frame is realized, and it is easy to understand that in this process, the frame tail synchronization sequence plays a role in frame isolation;

[0090] Finally, on the basis of frame synchronization, the intermediate signal is demodulated and decoded based on the modulation mode information and the coding mode information carried in the subframe (corresponding to the demodulation and decoding in Figure 1

[0091] Specifically, for example, on the basis of frame synchronization, the modulation mode and the LDPC code rate information used in the physical frame are determined from the characteristic sequence, the demodulation is completed by using the corresponding modulation mode, the demodulation result and the code rate information are input into the LDPC decoder, and the corresponding bit information is output.

[0092] In an embodiment, the application further provides a satellite communication transmission device, which applies the method for transmitting end described in the foregoing to perform data processing and signal transmission.

[0093] The specific manner in which the satellite communication transmission device in this embodiment performs operations has been described in detail in the embodiment related to the method, and will not be described in detail here.

[0094] In an embodiment, the application further provides a satellite communication transmission device, which applies the method for receiving end described in the foregoing to perform signal reception and receiving data processing.

[0095] The specific manner in which the satellite communication transmission device in this embodiment performs operations has been described in detail in the embodiment related to the method, and will not be described in detail here.

[0096] The above is only the preferred specific implementation of the application, but the protection scope of the application is not limited to this, any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the application, which should be covered in the protection scope of the application. Therefore, the protection scope of the application should be subject to the protection scope of the claims.​

Claims

1. A satellite communication transmission method, applied to a sending end, characterized in that, The method comprises: encoding source data and framing the encoding output data based on an agreed subframe structure; performing symbol mapping processing on the framed output subframes to generate a first baseband signal; performing pulse shaping processing on the first baseband signal to obtain a second baseband signal with improved inter-symbol interference; performing up-conversion and digital-to-analog conversion processing on the second baseband signal to obtain an analog signal that meets the requirements of a transmission frequency point and a sampling rate, and performing signal transmission; wherein the subframe structure comprises a frame header synchronization sequence, a feature sequence for carrying modulation mode information and encoding mode information, a data payload sequence for carrying valid data information, and a frame tail synchronization sequence; in the subframe structure, the frame header synchronization sequence, the feature sequence, the data payload sequence, and the frame tail synchronization sequence are arranged in sequence, and the end of each sequence is sequentially inserted with a symbol pilot, and each symbol pilot constitutes a unique word sequence for implementing a preset function; the subframe structure has a total of 8448 symbols; wherein: the number of frame header synchronization sequences is 2, which are a first frame header synchronization sequence and a second frame header synchronization sequence in sequence; the number of feature sequences is 1; the number of data payload sequences is 128; and the number of frame tail synchronization sequences is 1; the symbol length of the first frame header synchronization sequence, the second frame header synchronization sequence, the feature sequence, the data payload sequence, and the frame tail synchronization sequence is 63 symbols; the first frame header synchronization sequence, the second frame header synchronization sequence, the feature sequence, and the frame tail synchronization sequence are all binary sequences, and in the communication process, each binary sequence is configured to be equivalent to its reverse sequence.

2. The method of claim 1, wherein: in the process of encoding the source data, the encoding mode is LDPC encoding; the frame header synchronization sequence, the feature sequence, the frame tail synchronization sequence, and the unique word sequence are all generated by BPSK modulation; the data payload sequence is generated by one or more of BPSK, QPSK, 8PSK, 16APSK, and 16QAM modulation.

3. The method of claim 1, wherein, the pulse shaping processing mode comprises: zero-padding interpolation is performed on the first baseband signal, and the zero-padding interpolated baseband signal is passed through a root-raised cosine filter to obtain the second baseband signal. 4.A satellite communication transmission method applied to a receiving end, characterized in that, The method comprises: performing analog-to-digital conversion and down-conversion processing on the received analog signal to obtain a baseband digital signal; performing matching filter processing on the baseband digital signal corresponding to the pulse shaping processing at the transmitting end; performing frame positioning on the intermediate signal obtained by the matching filter processing based on an agreed subframe structure to achieve frame synchronization; based on the frame synchronization, performing demodulation and decoding processing on the intermediate signal based on the modulation mode information and the encoding mode information carried in the subframe to obtain the transmitted valid data; wherein the subframe structure comprises a frame header synchronization sequence, a feature sequence for carrying modulation mode information and encoding mode information, a data payload sequence for carrying transmission data information, and a frame tail synchronization sequence; The frame head synchronization sequence, the feature sequence, the data payload sequence and the frame tail synchronization sequence are arranged in sequence in the subframe structure, and a symbol pilot is inserted at the end of each sequence in sequence, and each symbol pilot constitutes a unique word sequence for realizing a preset function; There are 8448 symbols in the subframe structure in total; Among them: The number of the frame head synchronization sequence is 2, and the first frame head synchronization sequence and the second frame head synchronization sequence are arranged in sequence; the number of the feature sequence is 1; the number of the data payload sequence is 128; and the number of the frame tail synchronization sequence is 1; The symbol length of the first frame head synchronization sequence, the second frame head synchronization sequence, the feature sequence, the data payload sequence and the frame tail synchronization sequence is 63 symbols; The first frame head synchronization sequence, the second frame head synchronization sequence, the feature sequence and the frame tail synchronization sequence are all binary sequences, and each binary sequence is configured to be equal to its reverse sequence in the communication process.

5. The method of claim 4, wherein, The code rate information of the LDPC coding is included in the encoding mode information; The frame head synchronization sequence, the feature sequence, the frame tail synchronization sequence and the unique word sequence are all generated by BPSK modulation; The symbol in the data payload sequence is generated by one or more of BPSK, QPSK, 8PSK, 16APSK and 16QAM modulation.

6. The method of claim 4, wherein, In the process of realizing frame synchronization, the process includes: Correlating the locally stored first frame head synchronization sequence with the intermediate signal, and determining that the subframe is captured according to the correlation value; Then, correlating the locally stored second frame head synchronization sequence with the received signal to realize frame synchronization.

7. A satellite communication transmission apparatus, characterized by comprising: The method of any one of claims 1 to 3 is applied to transmit data processing and signal transmission.

8. A satellite communication transmission apparatus, characterized by comprising: The method of any one of claims 4 to 6 is applied to signal reception and received data processing.

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