CN114095055B - Low-code rate biorthogonal code coding spreading method and device - Google Patents
Low-code rate biorthogonal code coding spreading method and device Download PDFInfo
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
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- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/69—Spread spectrum techniques
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- H—ELECTRICITY
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- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
- H04L1/0001—Systems modifying transmission characteristics according to link quality, e.g. power backoff
- H04L1/0002—Systems modifying transmission characteristics according to link quality, e.g. power backoff by adapting the transmission rate
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
- H04L1/0001—Systems modifying transmission characteristics according to link quality, e.g. power backoff
- H04L1/0006—Systems modifying transmission characteristics according to link quality, e.g. power backoff by adapting the transmission format
- H04L1/0007—Systems modifying transmission characteristics according to link quality, e.g. power backoff by adapting the transmission format by modifying the frame length
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L7/00—Arrangements for synchronising receiver with transmitter
- H04L7/0008—Synchronisation information channels, e.g. clock distribution lines
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Abstract
The invention provides a spread spectrum method and a device for low-bit rate biorthogonal code coding, wherein the method comprises the following steps: determining a spreading ratio and a target code rate of a signal to be coded; determining a sequence corresponding to a code word with the code rate identical to the target code rate and the code length of a preset length based on a code set of a biorthogonal code encoder, wherein the sequence is used as a first sequence for generating a pilot frequency band after the spread spectrum of a signal to be encoded; and generating a corresponding code word based on the first sequence and repeating for a certain number of times to be used as a pilot frequency band after the signal to be coded is spread. The low-bit rate biorthogonal code coding frequency spreading method provided by the invention has the advantages that certain code words coded by the low-bit rate biorthogonal code coder have good autocorrelation signals, a frequency spreading module is omitted, a channel coding module is multiplexed, the low-bit rate biorthogonal code coder replaces the frequency spreading module of the traditional spread spectrum communication system, and the low-bit rate coder is multiplexed, so that the structure of the coder is simplified.
Description
Technical Field
The invention relates to the technical field of channel coding and decoding, in particular to a low-code-rate biorthogonal code coding spreading method and device.
Background
Spread spectrum is an important means in satellite communication, the satellite is relatively far away from the earth, the satellite has limited transmission power and low received signal-to-noise ratio, and therefore, a spread spectrum communication system is required to be used, such as: direct Sequence Spread Spectrum (DSSS) uses a high-speed pseudorandom code to Spread and modulate low-speed data to be transmitted, and can still maintain good communication performance under the conditions of low signal-to-noise ratio and complex communication system environment. Generally, because a satellite transmitting terminal adopts a simpler transmitting device, the resource of the satellite transmitting terminal is very limited, and a traditional spread spectrum communication system needs a larger spread spectrum ratio to ensure the receiving accuracy under the conditions of low signal to noise ratio and severe communication environment.
Reliable transmission of information at high power utilization is one of the important goals pursued by communication systems, and channel coding techniques are an effective way to achieve this goal. Low complexity, high coding gain channel coding is widely used in the fields of deep space communication, fiber optic communication, satellite Digital video, Digital watermarking, magnetic/optical/holographic storage, mobile and fixed wireless communication, cable modulators/demodulators, Digital Subscriber Lines (DSL), and the like. With the research on the channel coding technology, it is gradually found that a channel coding scheme with a lower code rate, such as an LDPC code (Low-density Parity-check) combined with hadamard coding and a turbo code, still has good performance under a very Low signal-to-noise ratio, but the code length is long, and a daily communication system does not need to work in such a harsh environment, and thus cannot be applied to an ordinary communication system.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides a low-bit-rate bi-orthogonal code decoder and a method thereof.
In a first aspect, the present invention provides a spreading method for low-rate bi-orthogonal code coding, including:
determining a spreading ratio and a target code rate of a signal to be coded;
determining a sequence corresponding to a code word with the code rate identical to the target code rate and the code length of a preset length based on a code set of a biorthogonal code encoder, wherein the sequence is used as a first sequence for generating a pilot frequency band after the spread spectrum of a signal to be encoded;
generating a corresponding code word based on the first sequence and repeating for a certain number of times to serve as a pilot frequency band after the signal to be coded is spread;
the preset length is the length of a single character after spread spectrum according to a spread spectrum ratio; the specific number of times is determined based on a frame structure corresponding to a signal-to-noise ratio of the receiver.
Optionally, the method further comprises: determining a sequence corresponding to a code word with the same code rate as the target code rate and the code length being a multiple of a specific value based on a code set of a double-orthogonal code encoder, and taking the sequence as a second sequence of a frame synchronization head for generating a signal to be encoded;
determining an encoding result of a signal to be encoded based on the first sequence, the second sequence, the signal to be encoded and the spreading ratio;
the specific value is determined based on a frame synchronization algorithm.
Optionally, the determining a coding result of the signal to be coded based on the first sequence, the second sequence, the signal to be coded and the spreading ratio includes:
generating a corresponding code word based on the first sequence and repeating for a certain number of times to serve as a pilot frequency band after the signal to be coded is spread;
determining a data framing based on the second sequence and the signal to be encoded;
determining an encoding result of a bi-orthogonal code of a signal to be encoded based on the data framing;
the specific number of times is determined based on a frame structure corresponding to a signal-to-noise ratio of the receiver.
Optionally, after generating a corresponding codeword based on the first sequence and repeating the codeword for a preset number of times as a pilot segment after spreading a signal to be coded, the method further includes:
resetting the biorthogonal code encoder.
Optionally, the bi-orthogonal code encoder implements a related process flow based on a state machine, the state machine including: initial reset, sending frame synchronous head for capture, resetting after sending frame synchronous head, framing, synchronous head and data coding to be sent.
In a second aspect, the present invention further provides a spreading device for low-rate bi-orthogonal code coding, including:
the determining module is used for determining the spreading ratio and the target code rate of the signal to be coded;
the first sequence module is used for determining a sequence corresponding to a code word with the code length being a preset length and the code rate being the same as the target code rate based on a code set of a double-orthogonal code encoder, and the sequence is used as a first sequence for generating a pilot frequency band after the spread spectrum of a signal to be encoded;
the pilot frequency generation module generates a corresponding code word based on the first sequence and repeats the code word for a certain number of times to serve as a pilot frequency band after the spread spectrum of the signal to be coded;
the preset length is the length of a single character after spread spectrum according to a spread spectrum ratio; the specific number of times is determined based on a frame structure corresponding to a signal-to-noise ratio of the receiver.
Optionally, the apparatus further comprises:
a frame synchronization head generating module, configured to determine, based on a code set of a biorthogonal code encoder, a sequence corresponding to a codeword with a code rate that is the same as the target code rate and a code length that is a multiple of a specific value, as a second sequence of a frame synchronization head for generating a signal to be encoded;
a spreading module, configured to determine a coding result of a signal to be coded based on the first sequence, the second sequence, the signal to be coded, and the spreading ratio;
the specific value is determined based on a frame synchronization algorithm.
Optionally, the spreading module is further configured to:
generating a corresponding code word based on the first sequence and repeating for a certain number of times to serve as a pilot frequency band after the signal to be coded is spread;
determining a data framing based on the second sequence and the signal to be encoded;
determining an encoding result of a bi-orthogonal code of a signal to be encoded based on the data framing;
the specific number of times is determined based on a frame structure corresponding to a signal-to-noise ratio of the receiver.
Optionally, the spreading module is further configured to generate a corresponding codeword based on the first sequence, repeat the codeword for a preset number of times, and reset the biorthogonal code encoder after the codeword is used as a pilot segment after spreading a signal to be encoded.
Optionally, the bi-orthogonal code encoder implements a related process flow based on a state machine, the state machine including: initial reset, sending frame synchronous head for capture, resetting after sending frame synchronous head, framing, synchronous head and data coding to be sent.
In a third aspect, the present invention also provides an electronic device, comprising a memory, a transceiver, a processor;
a memory for storing a computer program; a transceiver for transceiving data under control of the processor; a processor for reading the computer program in the memory and implementing the steps of the spreading method of low-rate bi-orthogonal code coding as described above in the first aspect.
In a fourth aspect, the present invention further provides a computer-readable storage medium, which stores a computer program for causing a computer to implement the steps of the spreading method of low-rate bi-orthogonal code coding according to the first aspect when executed.
In a fifth aspect, the present invention also provides a computer program product comprising a computer program which, when executed by a processor, implements the steps of the spreading method for low-rate bi-orthogonal code coding as described above in the first aspect.
In a sixth aspect, the present invention further provides a processor-readable storage medium, which stores a computer program for causing a processor to implement the steps of the spreading method of low-rate bi-orthogonal code coding according to the first aspect when the processor executes the computer program.
The spread spectrum method and the device of the low-bit rate biorthogonal code coding provided by the invention have the advantages that certain code words coded by the low-bit rate biorthogonal code coder have good autocorrelation signals, a spread spectrum module is omitted, a channel coding module is multiplexed, the low-bit rate biorthogonal code coder replaces the spread spectrum module of a traditional spread spectrum communication system transmitting end, and the low-bit rate coder is multiplexed, so that the structure of the coder is simplified.
Drawings
In order to more clearly illustrate the technical solutions of the present invention or the prior art, the drawings needed for the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.
FIG. 1 is a schematic flow chart of a low-rate biorthogonal code encoding spreading method provided by the present invention;
FIG. 2 is a schematic structural diagram of a low-rate biorthogonal code-coded spread spectrum device according to the present invention;
fig. 3 is a second schematic structural diagram of a low-rate bi-orthogonal code spreading apparatus according to the present invention;
FIG. 4 is a schematic diagram of a spread spectrum device for low-rate biorthogonal code encoding according to the present invention;
fig. 5 is a schematic physical structure diagram of an electronic device provided in the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is obvious that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The spreading method and device of low-rate bi-orthogonal code coding of the present invention are described below with reference to fig. 1-5.
For a satellite spread spectrum communication system, the spread spectrum can be replaced by channel coding with the same code rate, so that the communication system can still keep better performance in a harsh working environment with low signal to noise ratio, and compared with a spread spectrum system, coding gain can be introduced into low-code-rate coding and decoding.
In order to ensure that the communication system can still maintain better performance in a harsh working environment with low signal-to-noise ratio and simplify the originating of the traditional spread spectrum communication system, the invention provides a method for carrying out spread spectrum communication by replacing spread spectrum with low-code-rate codes. When the method is used for communication, the problem that a transmitting end module of a traditional spread spectrum communication system is complex can be solved. Compared with the traditional sending module, the sending device of the invention omits the spread spectrum module, multiplexes the channel coding module and reduces the complexity of the sending device.
FIG. 1 is a schematic flow chart of a low-rate biorthogonal code encoding spreading method provided by the present invention; as shown in fig. 1, the method includes:
step 102, determining a sequence corresponding to a code word with the same code rate as the target code rate and the preset code length based on a code set of a biorthogonal code encoder, and taking the sequence as a first sequence for generating a pilot frequency band after the spread spectrum of a signal to be encoded;
103, generating a corresponding code word based on the first sequence and repeating the code word for a certain number of times to serve as a pilot frequency band after the spread spectrum of the signal to be coded;
the preset length is the length of a single character after spread spectrum according to a spread spectrum ratio; the specific number of times is determined based on a frame structure corresponding to a signal-to-noise ratio of the receiver.
Specifically, a signal encoded by a low-rate biorthogonal code encoder has a low code rate, corresponding code words have strong autocorrelation, and the cross correlation between the code words is poor.
After receiving a signal to be encoded, based on the signal-to-noise ratio of the opposite-end receiver, etc., determining the spreading code word length corresponding to the signal, i.e., the spreading ratio, where an original signal is 1 bit, and a spread signal is 128 bits, then the corresponding spreading ratio is 128, where an original signal is 2 bits, and a spread signal is 1024 bits, then the corresponding spreading ratio is 512.
And confirming the corresponding code rate, namely the target code rate, based on the relevant parameters of the receiver.
Selecting code words with code rates consistent with the target code rate by using a code set of a double-orthogonal code encoder, then screening out code words meeting the spreading ratio from the screened code words with the consistent target code rate based on the spreading ratio, and determining a sequence corresponding to the code words to be used as a first sequence of a pilot frequency band after spreading of a signal to be encoded.
Then, according to the first sequence, generating corresponding code word, and repeating transmitting for a certain times. The first times is to determine a data frame structure required to be adopted according to the signal-to-noise ratio requirement of the receiver, and then determine the times required to be sent according to the code words generated by the first sequence according to the length of the pilot frequency band in the data frame structure.
For example, a code set of a bi-orthogonal code encoder with a code length of N and a code rate of k is screened to select a group of code words c with excellent autocorrelation0The chips after pilot band spreading, i.e. the sequences after pilot band (all 1 part) spreading of the spread spectrum communication system, are used to replace the direct spreading result of all 1 sequences in the conventional spread spectrum communication sequence. The code length N is consistent with the chip length after single symbol is spread, and the code word c is stored0Sequence x before coding0The sequence x can be encoded by the originating encoder0Encoding into code words c0And by repeatedly transmitting the code word c0The function of the original pilot band can be completed. The biorthogonal code matrix of the biorthogonal code encoder is a binary matrix known a priori, and is composed of +1 and-1.
The low-bit rate biorthogonal code coding frequency spreading method provided by the invention has the advantages that certain code words coded by the low-bit rate biorthogonal code coder have good autocorrelation signals, a frequency spreading module is omitted, a channel coding module is multiplexed, the low-bit rate biorthogonal code coder replaces the frequency spreading module of the traditional spread spectrum communication system, and the low-bit rate coder is multiplexed, so that the structure of the coder is simplified.
Optionally, the method further comprises:
determining a sequence corresponding to a code word with the same code rate as the target code rate and the code length being a multiple of a specific value based on a code set of a double-orthogonal code encoder, and taking the sequence as a second sequence of a frame synchronization head for generating a signal to be encoded;
determining an encoding result of a signal to be encoded based on the first sequence, the second sequence, the signal to be encoded and the spreading ratio;
the specific value is determined based on a frame synchronization algorithm.
Specifically, after the pilot frequency band of the signal to be encoded is determined, a frame synchronization word or a frame synchronization header of the signal to be encoded also needs to be determined, a code set of a biorthogonal code encoder is also used, a code word with the same code rate as a target code rate is selected from the code word, then, in the code word with the same code rate, whether the corresponding code length meets a specific value multiple or not is further determined, for example, if the code length corresponding to the frame synchronization algorithm is required to be 32 bits, the specific value is 32, that is, a code word with the code length of 32 times is selected from the code words with the same code rate, and then, a second sequence corresponding to the code word is determined and is used as a second sequence for generating the frame synchronization header of the signal to be encoded.
In the frame synchronization process, a short sequence with excellent autocorrelation and length P is spread and then transmitted, and the spread spectrum mode is direct sequence spread spectrum. And then, despreading the received signal at a receiving end, and then carrying out frame synchronization on the despread, wherein the data received by the frame synchronization module only has energy accumulation gain caused by the despread, and for a system with small spread spectrum, the signal-to-noise ratio required by the frame synchronization can not be achieved simply by the method.
In the present invention, a code word c with length L/k is selected1The code word corresponds to the sequence x1Also has good autocorrelation. Where L is the spreading ratio and k is the code rate. k represents the code rate of the low-rate biorthogonal code, is determined by the properties of the biorthogonal code itself, and is a number between 0 and 1. Also only the code word c needs to be stored at the originating end1Sequence x before coding1Sequence x is transmitted1Inputting the data into a low-code-rate coding system, and transmitting the data after the low-code-rate coding. After receiving the information, the receiving end can directly decode all the signals with low code rate and perform frame synchronization on the decoding result. At this time, not only the gain caused by energy accumulation, but also the gain caused by low-code-rate coding can further improve the accuracy of frame synchronization.
And then, according to the first sequence, the second sequence and the signal to be coded, combining the determined spreading ratio to determine a coding result of the signal to be coded. The coding result corresponds to the actual spreading result, because the essence of the invention is to implement the spreading function in a coded form.
Optionally, the determining a coding result of the signal to be coded based on the first sequence, the second sequence, the signal to be coded and the spreading ratio includes:
generating a corresponding code word based on the first sequence and repeating for a certain number of times to serve as a pilot frequency band after the signal to be coded is spread;
determining a data framing based on the second sequence and the signal to be encoded;
determining an encoding result of a bi-orthogonal code of a signal to be encoded based on the data framing;
the specific number of times is determined based on a frame structure corresponding to a signal-to-noise ratio of the receiver.
Specifically, the essence of the present invention is to implement a spread spectrum function by means of coding, after a first sequence of a pilot band is determined, a low-rate bi-orthogonal code encoder is input, and a certain number of code words are repeatedly generated, wherein the code words correspond to the first sequence one by one. The number of times of repeated generation is based on the signal-to-noise ratio of the receiver, the frame structure of transmission is determined, the number of bits of the pilot band is determined based on the characteristics of the frame structure, and then the number of times of repeated transmission of the code words is determined, and the number of bits of each code word meets the aforementioned spreading ratio, for example, the spreading ratio is 1024, and for a single symbol of an original signal, the number of bits of the code word is 1024.
In the above step, a second sequence of the frame sync header of the signal to be encoded is determined, such as sequence x1Then the sequence x1Splicing with a signal to be coded (which can also be service data) to obtain a sequence x2And waiting for inputting the low-code rate biorthogonal code encoder. Such as the sequence x1Is 000, the service data is 111111111, then the sequence x2Is 000111111111.
Then the above sequence x2And inputting the low-code rate biorthogonal code encoder, and determining the encoding result of biorthogonal codes of the signal to be encoded.
Optionally, after generating a corresponding codeword based on the first sequence and repeating the codeword for a preset number of times as a pilot segment after spreading a signal to be coded, the method further includes:
resetting the biorthogonal code encoder.
Specifically, the sequence x is2Before inputting low-bit rate biorthogonal code encoder, need reset low-bit rate biorthogonal code encoder, because this low-bit rate biorthogonal code encoder has memory function to data or signal that the previous processing led to the fact the influence this time to handling, need reset low-bit rate biorthogonal code encoder, the initial condition of guaranteeing the encoder is all zero or specific sequence, such purpose is when guaranteeing follow-up synchronization head and data entering encoder irrelevant with preceding capture sequence, promptly: regardless of the capture sequence and capture position.
Optionally, the bi-orthogonal code encoder implements a related process flow based on a state machine, the state machine including: initial reset, sending frame synchronous head for capture, resetting after sending frame synchronous head, framing, synchronous head and data coding to be sent.
Specifically, the implementation of all the above steps can be judged and implemented in the biorthogonal code encoder by using a state machine, and the state machine has 5 states:
the state 1 is initial reset and represents that the initial state of the biorthogonal code encoder is cleared; the state is a reset state before each packet of data is sent, and the initial state of the low-code rate biorthogonal code encoder needs to be cleared, so that the initial state of the encoder is all zeros or a specific sequence.
State 2 is a frame synchronization header for transmission and capture, which indicates that encoding is performed based on the first sequence, and the encoded code word is cached and repeated for a certain number of times; in this state, the sequence x0Pushing into the encoder, and encoding the result code word c0Buffering is performed, and M times of repeated sending are used for capturing.
The state 3 is that the frame synchronization head is sent and then reset, which indicates that the biorthogonal code encoder needs to reset again after encoding is executed; in this state, it is also necessary to reset the low-rate biorthogonal encoder, and the initial state of the encoder is guaranteed to be an all-zero or specific sequence, so as to ensure that the subsequent sync header and data enter the encoder independently of the previous capture sequence, that is: regardless of the capture sequence and capture position.
State 4 is framing or framing of the frame synchronization header and the data to be transmitted, which indicates splicing of the second sequence and the service data; in this state, the sequence x1And forming a continuous sequence with the service data to be transmitted, and obtaining a complete sequence x at the moment2Length is sequence x1And the sum of the length of the data and the length of the service data to be transmitted.
State 5 is the frame sync header and the data to be transmitted are encoded, which means the frame sync header and the data to be transmitted are encoded by the encoder. In this state, the sequence x2Pushing into the encoder to obtain the code word c to be sent3The head sequence of the code word is the code word c1And the subsequent part is the result of data encoding. It is to be noted that the encoding of the traffic data by the encoder does not start from an all-zero state, but with a sequence x for frame synchronization1At the end of encoding, the state of the encoder is encoded as the initial state.
The low-bit rate biorthogonal code coding frequency spreading method provided by the invention has the advantages that certain code words coded by the low-bit rate biorthogonal code coder have good autocorrelation signals, a frequency spreading module is omitted, a channel coding module is multiplexed, the low-bit rate biorthogonal code coder replaces the frequency spreading module of the traditional spread spectrum communication system, and the low-bit rate coder is multiplexed, so that the structure of the coder is simplified. Because of the low code rate coding, the performance is better than the combination of the higher code rate channel coding and the direct spread spectrum sequence under the same spread spectrum ratio.
Fig. 2 is a schematic structural diagram of a spreading apparatus for low-rate bi-orthogonal code coding provided in the present invention, and as shown in fig. 2, the spreading apparatus for low-rate bi-orthogonal code coding includes:
a determining module 201, configured to determine a spreading ratio and a target code rate of a signal to be encoded;
a first sequence module 202, configured to determine, based on a code set of a biorthogonal code encoder, a sequence corresponding to a codeword with a code rate that is the same as the target code rate and a code length of a preset length, and use the sequence as a first sequence for generating a pilot segment after spreading a signal to be encoded;
a pilot generating module 203, configured to generate a corresponding codeword based on the first sequence and repeat the codeword for a certain number of times, where the codeword is used as a pilot segment after spreading a signal to be coded;
the preset length is the length of a single character after spread spectrum according to a spread spectrum ratio; the specific number of times is determined based on a frame structure corresponding to a signal-to-noise ratio of the receiver.
Specifically, a signal encoded by a low-rate biorthogonal code encoder has a low code rate, corresponding code words have strong autocorrelation, and the cross correlation between the code words is poor.
The determining module 201 determines, based on a signal to be encoded and a signal-to-noise ratio of an opposite-end receiver, a spreading code word length corresponding to the signal, that is, a spreading ratio, where an original signal is 1 bit, a spread signal is 128 bits, a corresponding spreading ratio is 128 bits, for example, the original signal is 2 bits, the spread signal is 1024 bits, and a corresponding spreading ratio is 512.
And confirming the corresponding code rate, namely the target code rate, based on the relevant parameters of the receiver.
The first sequence module 202 selects code words with code rates consistent with the target code rate by using the above characteristics of the code set in the bi-orthogonal code encoder, then selects code words meeting the spreading ratio from the selected code words with the target code rate based on the spreading ratio, and determines a sequence corresponding to the code words as a first sequence of the pilot frequency band after spreading the signal to be encoded.
The pilot generating module 203 generates a corresponding codeword according to the first sequence, and retransmits the codeword for a certain number of times. The first times is to determine a data frame structure required to be adopted according to the signal-to-noise ratio requirement of the receiver, and then determine the times required to be sent according to the code words generated by the first sequence according to the length of the pilot frequency band in the data frame structure.
For example, a code set of a bi-orthogonal code encoder with a code length of N and a code rate of k is screened to select a group of code words c with excellent autocorrelation0The chips after pilot band spreading, i.e. the sequences after pilot band (all 1 part) spreading of the spread spectrum communication system, are used to replace the direct spreading result of all 1 sequences in the conventional spread spectrum communication sequence. The code length N is consistent with the chip length after single symbol is spread, and the code word c is stored0Sequence x before coding0The sequence x can be encoded by the originating encoder0Encoding into code words c0And by repeatedly transmitting the code word c0The function of the original pilot band can be completed.
The low-bit rate biorthogonal code coded spread spectrum device provided by the invention has the advantages that certain code words have good autocorrelation signals after being coded by the low-bit rate biorthogonal code coder, a spread spectrum module is omitted, a channel coding module is multiplexed, the low-bit rate biorthogonal code coder replaces the spread spectrum module of the traditional spread spectrum communication system, and the low-bit rate coder is multiplexed, so that the structure of the coder is simplified.
Optionally, the apparatus further comprises:
a frame synchronization head generating module, configured to determine, based on a code set of a biorthogonal code encoder, a sequence corresponding to a codeword with a code rate that is the same as the target code rate and a code length that is a multiple of a specific value, as a second sequence of a frame synchronization head for generating a signal to be encoded;
a spreading module, configured to determine a coding result of a signal to be coded based on the first sequence, the second sequence, the signal to be coded, and the spreading ratio;
the specific value is determined based on a frame synchronization algorithm.
Optionally, the spreading module is further configured to:
generating a corresponding code word based on the first sequence and repeating for a certain number of times to serve as a pilot frequency band after the signal to be coded is spread;
determining a data framing based on the second sequence and the signal to be encoded;
determining an encoding result of a bi-orthogonal code of a signal to be encoded based on the data framing;
the specific number of times is determined based on a frame structure corresponding to a signal-to-noise ratio of the receiver.
Optionally, the spreading module is further configured to generate a corresponding codeword based on the first sequence, repeat the codeword for a preset number of times, and reset the biorthogonal code encoder after the codeword is used as a pilot segment after spreading a signal to be encoded.
Optionally, the bi-orthogonal code encoder implements a related process flow based on a state machine, the state machine including: initial reset, sending frame synchronous head for capture, resetting after sending frame synchronous head, framing, synchronous head and data coding to be sent.
The low-bit rate biorthogonal code coded spread spectrum device provided by the invention has the advantages that certain code words have good autocorrelation signals after being coded by the low-bit rate biorthogonal code coder, a spread spectrum module is omitted, a channel coding module is multiplexed, the low-bit rate biorthogonal code coder replaces the spread spectrum module of the traditional spread spectrum communication system, and the low-bit rate coder is multiplexed, so that the structure of the coder is simplified. Because of the low code rate coding, the performance is better than the combination of the higher code rate channel coding and the direct spread spectrum sequence under the same spread spectrum ratio.
The overall concept of the invention is illustrated below with specific examples.
Fig. 3 is a second schematic structural diagram of a spreading apparatus for low-rate bi-orthogonal code coding according to the present invention. As shown in fig. 3, the apparatus includes: a pilot generation module 301, a frame synchronization header generation module 302, and a low-rate biorthogonal code encoding module 303. Mainly by using low code rate coding to a specific sequence to replace the spread spectrum function.
1. The pilot generation module 301:
screening a code set of a biorthogonal code encoder with the code length of N and the code rate of k, and selecting a group of code words c with excellent autocorrelation0AsThe pilot band spread chips, i.e. the sequences after pilot band (all 1 part) spreading of the spread spectrum communication system, are used to replace the direct spreading result of all 1 sequences in the conventional spread spectrum communication sequence. The code length N is consistent with the chip length after single symbol is spread, and the code word c is stored0Sequence x before coding0The sequence x can be encoded by the originating encoder0Encoding into code words c0And by repeatedly transmitting the code word c0The function of the original pilot band can be completed.
At this time, the length that needs to be stored is m = N × k, the receiving portion needs to perform sliding correlation on the signal transmitted at this time by using the code length N, and the result after the correlation is accumulated, so that the transmitted signal can be captured without introducing a more complicated structure.
2. Frame synchronization header generation module 302
The common practice of the frame synchronization module is to spread a short sequence with excellent autocorrelation and length L, and transmit the spread sequence after spreading, where the spreading mode is direct sequence spreading. Then, the received signal is de-spread at the receiving end, and then the de-spread is frame-synchronized, at this time, the data received by the frame synchronization module only has energy accumulation gain caused by the de-spread, and for a system with small spread spectrum, the signal-to-noise ratio required by the frame synchronization may not be achieved by only the method.
In the present invention, a code word c with length L/k is selected1The code word corresponds to the sequence x1Also has good autocorrelation. Also only the code word c needs to be stored at the originating end1Sequence x before coding1Sequence x is transmitted1Inputting the data into a low-code-rate coding system, and transmitting the data after the low-code-rate coding. After receiving the information, the receiving end can directly decode all the signals with low code rate and perform frame synchronization on the decoding result. At this time, not only the gain caused by energy accumulation, but also the gain caused by low-code-rate coding can further improve the accuracy of frame synchronization.
3. Low-rate biorthogonal code coding module 303
This part structureA lower rate biorthogonal code is created and the encoder is multiplexed. The whole encoder needs to carry out two encoding outputs in the sending stage, and the first time needs to carry out encoding output according to the sequence x0Generating a codeword c0And repeatedly sending the data for system acquisition; as in fig. 4
As shown. The second time, the sequence x needs to be added1The data and the service data to be transmitted form a complete data frame, and the data frame is input into the low-bit-rate orthogonal code encoding module together and then transmitted, as shown in fig. 4
As shown. Taking spreading ratio 1024 as an example, the code word c after spreading0The number of bits of (1) is the number of bits of the original symbol corresponding to (1024), and the code word c after spreading1The number of bits of the spread spectrum is the number of bits of the original symbol which corresponds to the spread spectrum 1024, and the number of bits occupied by the spread spectrum user data is the number of bits occupied by the original service data 1024.
The method and the device provided by the embodiments of the invention are based on the same inventive concept, and because the principles of solving the problems of the method and the device are similar, the implementation of the device and the method can be mutually referred, and repeated parts are not repeated.
Fig. 5 is a schematic structural diagram of an electronic device according to an embodiment of the present invention, and as shown in fig. 5, the electronic device may include: a processor (processor)510, a communication Interface (Communications Interface)520, a memory (memory)530 and a communication bus 540, wherein the processor 510, the communication Interface 520 and the memory 530 communicate with each other via the communication bus 540. Processor 510 may invoke logic instructions in memory 530 to perform the steps of a spreading method for low-rate bi-orthogonal code encoding, including, for example:
determining a spreading ratio and a target code rate of a signal to be coded;
determining a sequence corresponding to a code word with the code rate identical to the target code rate and the code length of a preset length based on a code set of a biorthogonal code encoder, wherein the sequence is used as a first sequence for generating a pilot frequency band after the spread spectrum of a signal to be encoded;
generating a corresponding code word based on the first sequence and repeating for a certain number of times to serve as a pilot frequency band after the signal to be coded is spread;
the preset length is the length of a single character after spread spectrum according to a spread spectrum ratio; the specific number of times is determined based on a frame structure corresponding to a signal-to-noise ratio of the receiver.
Optionally, the steps further comprise:
determining a sequence corresponding to a code word with the same code rate as the target code rate and the code length being a multiple of a specific value based on a code set of a double-orthogonal code encoder, and taking the sequence as a second sequence of a frame synchronization head for generating a signal to be encoded;
determining an encoding result of a signal to be encoded based on the first sequence, the second sequence, the signal to be encoded and the spreading ratio;
the specific value is determined based on a frame synchronization algorithm.
Optionally, the determining a coding result of the signal to be coded based on the first sequence, the second sequence, the signal to be coded and the spreading ratio includes:
generating a corresponding code word based on the first sequence and repeating for a certain number of times to serve as a pilot frequency band after the signal to be coded is spread;
determining a data framing based on the second sequence and the signal to be encoded;
determining an encoding result of a bi-orthogonal code of a signal to be encoded based on the data framing;
the specific number of times is determined based on a frame structure corresponding to a signal-to-noise ratio of the receiver.
Optionally, after generating a corresponding codeword based on the first sequence and repeating the codeword for a preset number of times as a pilot segment after spreading a signal to be coded, the method further includes:
resetting the biorthogonal code encoder.
Optionally, the bi-orthogonal code encoder implements a related process flow based on a state machine, the state machine including: initial reset, sending frame synchronous head for capture, resetting after sending frame synchronous head, framing, frame synchronous head and data coding to be sent.
Furthermore, the logic instructions in the memory 530 may be implemented in the form of software functional units and stored in a computer readable storage medium when the software functional units are sold or used as independent products. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.
In another aspect, the present invention also provides a computer program product, the computer program product includes a computer program, the computer program can be stored on a non-transitory computer readable storage medium, when the computer program is executed by a processor, a computer can execute the spreading method of low-rate bi-orthogonal code coding provided by the above methods, for example, the spreading method includes:
determining a spreading ratio and a target code rate of a signal to be coded;
determining a sequence corresponding to a code word with the code rate identical to the target code rate and the code length of a preset length based on a code set of a biorthogonal code encoder, wherein the sequence is used as a first sequence for generating a pilot frequency band after the spread spectrum of a signal to be encoded;
generating a corresponding code word based on the first sequence and repeating for a certain number of times to serve as a pilot frequency band after the signal to be coded is spread;
the preset length is the length of a single character after spread spectrum according to a spread spectrum ratio; the specific number of times is determined based on a frame structure corresponding to a signal-to-noise ratio of the receiver.
In yet another aspect, the present invention also provides a non-transitory computer-readable storage medium, on which a computer program is stored, the computer program, when executed by a processor, implements a spreading method for low-rate bi-orthogonal code encoding provided by the above methods, for example, the spreading method includes:
determining a spreading ratio and a target code rate of a signal to be coded;
determining a sequence corresponding to a code word with the code rate identical to the target code rate and the code length of a preset length based on a code set of a biorthogonal code encoder, wherein the sequence is used as a first sequence for generating a pilot frequency band after the spread spectrum of a signal to be encoded;
generating a corresponding code word based on the first sequence and repeating for a certain number of times to serve as a pilot frequency band after the signal to be coded is spread;
the preset length is the length of a single character after spread spectrum according to a spread spectrum ratio; the specific number of times is determined based on a frame structure corresponding to a signal-to-noise ratio of the receiver.
The above-described embodiments of the apparatus are merely illustrative, and the units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.
Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware. With this understanding in mind, the above-described technical solutions may be embodied in the form of a software product, which can be stored in a computer-readable storage medium such as ROM/RAM, magnetic disk, optical disk, etc., and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the methods described in the embodiments or some parts of the embodiments.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (12)
1. A spreading method of low-rate bi-orthogonal code coding is characterized by comprising the following steps:
determining the spread spectrum ratio of a signal to be coded based on the signal-to-noise ratio of an opposite-end receiver;
determining a target code rate of the signal to be coded based on the relevant parameters of the opposite-end receiver;
determining a sequence corresponding to a code word with the code rate identical to the target code rate and the code length of a preset length based on a code set of a biorthogonal code encoder, wherein the sequence is used as a first sequence for generating a pilot frequency band after the spread spectrum of a signal to be encoded;
generating a corresponding code word based on the first sequence and repeating for a certain number of times to serve as a pilot frequency band after the signal to be coded is spread;
the preset length is the length of a single character after spread spectrum according to a spread spectrum ratio; the specific times are determined based on the number of bits of the pilot band in the frame structure corresponding to the signal-to-noise ratio of the receiver.
2. The method of spreading low-rate bi-orthogonal code according to claim 1, further comprising:
determining a sequence corresponding to a code word with the same code rate as the target code rate and the code length being a multiple of a specific value based on a code set of a double-orthogonal code encoder, and taking the sequence as a second sequence of a frame synchronization head for generating a signal to be encoded;
determining an encoding result of a signal to be encoded based on the first sequence, the second sequence, the signal to be encoded and the spreading ratio;
the specific value is determined based on a frame synchronization algorithm.
3. The method of claim 2, wherein the determining the encoding result of the signal to be encoded based on the first sequence, the second sequence, the signal to be encoded and the spreading ratio comprises:
generating a corresponding code word based on the first sequence and repeating for a certain number of times to serve as a pilot frequency band after the signal to be coded is spread;
determining a data framing based on the second sequence and the signal to be encoded;
determining an encoding result of a bi-orthogonal code of a signal to be encoded based on the data framing;
the specific number of times is determined based on a frame structure corresponding to a signal-to-noise ratio of the receiver.
4. The method of claim 3, wherein the generating a corresponding codeword based on the first sequence and repeating the codeword for a predetermined number of times as the pilot segment after spreading the signal to be encoded, further comprises:
resetting the biorthogonal code encoder.
5. The method of claim 1, wherein the biorthogonal code encoder implements the correlation process based on a state machine, and the state machine comprises: initial reset, sending frame synchronous head for capture, resetting after sending frame synchronous head, framing, frame synchronous head and data coding to be sent.
6. A spreading device for low-rate bi-orthogonal code coding, comprising:
the determining module is used for determining the spread spectrum ratio of the signal to be coded based on the signal-to-noise ratio of the opposite-end receiver; determining a target code rate of the signal to be coded based on the relevant parameters of the opposite-end receiver;
the first sequence module is used for determining a sequence corresponding to a code word with the code length being a preset length and the code rate being the same as the target code rate based on a code set of a double-orthogonal code encoder, and the sequence is used as a first sequence for generating a pilot frequency band after the spread spectrum of a signal to be encoded;
the pilot frequency generation module generates a corresponding code word based on the first sequence and repeats the code word for a certain number of times to serve as a pilot frequency band after the spread spectrum of the signal to be coded;
the preset length is the length of a single character after spread spectrum according to a spread spectrum ratio; the specific times are determined based on the number of bits of the pilot band in the frame structure corresponding to the signal-to-noise ratio of the receiver.
7. The low-rate bi-orthogonal code coded spreading device according to claim 6, wherein the device further comprises:
a frame synchronization head generating module, configured to determine, based on a code set of a biorthogonal code encoder, a sequence corresponding to a codeword with a code rate that is the same as the target code rate and a code length that is a multiple of a specific value, as a second sequence of a frame synchronization head for generating a signal to be encoded;
a spreading module, configured to determine a coding result of a signal to be coded based on the first sequence, the second sequence, the signal to be coded, and the spreading ratio;
the specific value is determined based on a frame synchronization algorithm.
8. The low-rate bi-orthogonal code coded spreading device according to claim 7, wherein the spreading module is further configured to:
generating a corresponding code word based on the first sequence and repeating for a certain number of times to serve as a pilot frequency band after the signal to be coded is spread;
determining a data framing based on the second sequence and the signal to be encoded;
determining an encoding result of a bi-orthogonal code of a signal to be encoded based on the data framing;
the specific number of times is determined based on a frame structure corresponding to a signal-to-noise ratio of the receiver.
9. The apparatus of claim 8, wherein the spreading module is further configured to generate a corresponding codeword based on the first sequence and repeat the codeword for a predetermined number of times as the pilot segment after spreading the signal to be encoded, and then reset the biorthogonal encoder.
10. The apparatus of claim 6, wherein the biorthogonal encoder implements the correlation process based on a state machine, the state machine comprising: initial reset, sending frame synchronous head for capture, resetting after sending frame synchronous head, framing, frame synchronous head and data coding to be sent.
11. An electronic device comprising a memory, a transceiver, a processor;
a memory for storing a computer program; a transceiver for transceiving data under control of the processor; a processor for executing the computer program in the memory and implementing the steps of the spreading method of low-rate bi-orthogonal code coding according to any of claims 1 to 5.
12. A computer-readable storage medium, characterized in that it stores a computer program for causing a computer to execute the steps of the spreading method of low-rate bi-orthogonal code coding according to any one of claims 1 to 5.
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