CN112769455B - Method, device, equipment and storage medium for generating aperiodic long code spreading code - Google Patents
Method, device, equipment and storage medium for generating aperiodic long code spreading code Download PDFInfo
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- 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
- H04B1/707—Spread spectrum techniques using direct sequence modulation
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- 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
- H04B1/707—Spread spectrum techniques using direct sequence modulation
- H04B1/7073—Synchronisation aspects
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- 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
- H04B1/707—Spread spectrum techniques using direct sequence modulation
- H04B1/7097—Interference-related aspects
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/14—Relay systems
- H04B7/15—Active relay systems
- H04B7/185—Space-based or airborne stations; Stations for satellite systems
- H04B7/1851—Systems using a satellite or space-based relay
- H04B7/18513—Transmission in a satellite or space-based system
Abstract
The invention provides a method, a device, equipment and a storage medium for generating an aperiodic long code spreading code, wherein the method comprises the following steps: determining a primitive polynomial and an initial phase of a local short-period spread spectrum code according to the PRN number, the week count and the intra-week day count of the satellite; generating a periodic short code according to the primitive polynomial and the initial phase; capturing burst frames according to the periodic short codes and carrying out frame synchronization; generating a first m sequence according to the primitive polynomial and the initial phase; processing the m1 sequence to obtain a decoding result of the user address; obtaining a second m sequence according to the primitive polynomial and the decoding result of the user address; and generating the spreading codes of the data segments according to the m1 sequence and the m2 sequence. The invention can generate the aperiodic long code spread spectrum code with variable initial phase, and effectively avoids the interference of illegal users.
Description
Technical Field
The present invention relates to the field of communications technologies, and in particular, to a method, an apparatus, a device, and a storage medium for generating an aperiodic long code spreading code.
Background
In the global short message system of Beidou No. three, a new signal system is adopted, and signals can possibly receive the interference of illegal users in the transmission process, so that the interference resistance is the problem which is not negligible in the short message system.
The direct sequence spread spectrum signal has the advantages of strong anti-interference capability, good confidentiality and high communication speed, so that the spread spectrum is widely applied as an important modulation technology.
The existing method aims at the problems that a non-periodic long code spread spectrum code has phase ambiguity, high algorithm complexity, incapability of considering both an m sequence and a Gold sequence and the like in the application process.
Disclosure of Invention
The invention provides a method, a device, equipment and a storage medium for generating a non-periodic long code spread spectrum code, which are used for solving the defects that the non-periodic long code spread spectrum code in the prior art has fuzzy phase, high algorithm complexity and incapability of considering both m sequence and Gold sequence in the application process, realizing the generation of the non-periodic long code spread spectrum code with variable initial phase and effectively avoiding the interference of illegal users.
The invention provides a method for generating an aperiodic long code spread spectrum code, which comprises the following steps: determining a primitive polynomial and an initial phase of a local short-period spread spectrum code according to a pseudo-random noise code (PRN) number, a week count and an intra-week day count of a satellite; generating a periodic short code according to the primitive polynomial and the initial phase; capturing burst frames according to the periodic short codes, and performing frame synchronization, wherein the burst frames comprise a synchronization head, a service section and a data section which are sequentially connected; generating a first m-sequence according to the primitive polynomial and the initial phase; processing the first m sequence to obtain a decoding result of the user address; obtaining a second m sequence according to the primitive polynomial and the decoding result of the user address; and generating the spread spectrum codes of the data segments according to the first m sequence and the second m sequence.
Before determining the primitive polynomial and the initial phase of the local short-period spreading code according to the PRN number week count and the intra-week day count of the satellite, the method for generating the aperiodic long-code spreading code further comprises the following steps: defining a user uplink signal frame protocol; and generating the burst frame according to the user uplink signal frame protocol.
According to the method for generating the aperiodic long code spread spectrum code, the service section comprises a precise heel, a frame identifier, a user address, an address check code, a reserved bit, a confirmation identifier, an inbound satellite number, an inbound serial number, a priority, a receiver type, a bit length indicator and identity authentication which are sequentially arranged; the data segment includes information category, user data, cyclic redundancy check bits, and a tail.
According to the method for generating the aperiodic long code spreading code provided by the invention, the first m sequence is a spreading code from the user address bit to the tail bit of the roll, and the second m sequence is a spreading code from the information type bit to the tail bit of the roll.
According to the method for generating an aperiodic long code spreading code provided by the present invention, the method for generating a spreading code of the data segment according to the first m-sequence and the second m-sequence comprises: and performing modulo-two addition operation on the first m sequence and the second m sequence to generate a Gold sequence, and using the Gold sequence as a spreading code of the data segment.
According to the method for generating the aperiodic long code spread spectrum code provided by the invention, the first m sequence is processed to obtain a decoding result of a user address, and the method comprises the following steps: and carrying out despreading, demodulation and decoding on the first m sequence in sequence to obtain a decoding result of the user address.
According to the method for generating an aperiodic long-code spreading code provided by the present invention, the primitive polynomial includes a generator polynomial of the first m-sequence and a generator polynomial of the second m-sequence.
The invention also provides a device for generating the aperiodic long code spread spectrum code, which comprises: the acquisition module is used for acquiring the PRN number, the week count and the intra-week day count of the satellite; the control processing module is used for determining a primitive polynomial and an initial phase of a local short-period spread spectrum code according to the PRN number of the satellite, the week count and the intra-week day count, and further generating a period short code according to the primitive polynomial and the initial phase; the control processing module is further used for capturing a burst frame through the acquisition module and performing frame synchronization, wherein the burst frame comprises a synchronization head, a service segment and a data segment which are sequentially connected; the control processing module is further configured to generate a first m sequence according to the primitive polynomial and the initial phase, and process the first m sequence to obtain a decoding result of the user address; the control processing module is further configured to obtain a second m-sequence according to the primitive polynomial and the decoding result of the user address, and generate a spreading code of the data segment according to the first m-sequence and the second m-sequence.
According to the device for generating the aperiodic long code spreading code provided by the invention, the control processing module is further used for defining a user uplink signal frame protocol, so that the satellite can generate the burst frame according to the user uplink signal frame protocol.
According to the generating device of the aperiodic long code spread spectrum code provided by the invention, the service section comprises a precise heel, a frame identifier, a user address, an address check code, a reserved bit, a confirmation identifier, an inbound satellite number, an inbound serial number, a priority, a receiver type, a bit length indicator and identity authentication which are sequentially arranged; the data segment includes information category, user data, cyclic redundancy check bits, and a tail.
According to the apparatus for generating an aperiodic long-code spreading code provided by the present invention, the first m-sequence is a spreading code from the user address bit to the tail bit of the convolution, and the second m-sequence is a spreading code from the information type bit to the tail bit of the convolution.
According to the device for generating the aperiodic long-code spreading code provided by the invention, the control processing module is configured to perform modulo two addition operation on the first m-sequence and the second m-sequence to generate a Gold sequence, and use the Gold sequence as the spreading code of the data segment.
According to the device for generating the aperiodic long code spread spectrum code, the control processing module is used for despreading, demodulating and decoding the first m sequence in sequence to obtain the decoding result of the user address.
According to the apparatus for generating an aperiodic long-code spreading code provided by the present invention, the primitive polynomial includes a generator polynomial of the first m-sequence and a generator polynomial of the second m-sequence.
The invention also provides an electronic device, which comprises a central control processor and a program stored in the central control processor and can be run, wherein the central control processor realizes the steps of the method for generating the aperiodic long code spreading code when executing the program.
The present invention also provides a non-transitory computer-readable storage medium having stored thereon a program which, when executed by a processor, implements the steps of the method for generating a non-periodic long code spreading code as described in any one of the above.
The method, the device, the equipment and the storage medium for generating the aperiodic long-code spread spectrum code determine a primitive polynomial and an initial phase of a local short-period spread spectrum code through a PRN (vertical random number) of a satellite, a week count and an intra-week day count, further generate a period short code according to the primitive polynomial and the initial phase, capture a burst frame based on the period short code, perform frame synchronization, perform spread spectrum according to the primitive polynomial and the initial phase to generate a first m sequence, process the first m sequence to obtain a decoding result of a user address, obtain a second m sequence according to the primitive polynomial and the decoding result of the user address, and finally generate a spread spectrum code of a data segment according to the first m sequence and the second m sequence. The invention supports the flexible switching of m sequence and Gold code, can effectively avoid the interference of illegal users and improve the safety of the system.
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 flowchart of a method for generating an aperiodic long-code spreading code according to the present invention;
fig. 2 is a format diagram of a satellite user uplink signal frame in an example of the present invention;
fig. 3 is a schematic flow chart of the on-line generation of spreading codes in an example of the present invention;
FIG. 4 is a schematic diagram of an r-stage linear shift register in one example of the invention;
fig. 5 is a diagram illustrating a structure of a spreading code of a user uplink signal according to an example of the present invention;
fig. 6 is a block diagram of a device for generating an aperiodic long-code spreading code according to the present invention;
fig. 7 is a schematic diagram of the structure of an electronic device in one example of the 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.
It should be appreciated that reference throughout this specification to "an embodiment" or "one embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearances of the phrase "in an embodiment" or "in one embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.
In the description of the present invention, it is to be understood that the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the term "connected" is to be interpreted broadly, e.g. as either directly or indirectly through intervening media. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
The method for generating the aperiodic long-code spreading code according to the present invention is described below with reference to fig. 1 to 5.
Fig. 1 is a flowchart of a method for generating an aperiodic long-code spreading code according to the present invention. As shown in fig. 1, the method for generating an aperiodic long-code spreading code provided by the present invention includes:
s0: defining a user uplink signal frame protocol, and generating a burst frame according to the user uplink signal frame protocol. When a plurality of short frames need to be sent, the first frame meets the requirement of the minimum frame length by a carrier extension method, and the frame is called a burst frame.
Fig. 2 is a format diagram of a satellite user uplink signal frame in one example of the invention. As shown in fig. 2, in the present example, a burst frame includes a synchronization header, a service segment, and a data segment, which are connected in sequence. The service section comprises a precise heel, a frame identifier, a user address, an address check code, a reserved bit, a confirmation identifier, an inbound satellite number, an inbound serial number, a priority, a receiver type, a bit length indicator and identity authentication which are sequentially arranged. The data segment includes information categories, user data, cyclic redundancy check bits, and a tail.
Wherein, the sync head is 50bit, used for the satellite to the acquisition of user's uplink signal.
The fine tracking is 16 bits and is used for pseudo code tracking and carrier recovery after the satellite captures the uplink signal of the user.
The frame is identified with 16bit and is used as a mark for indicating the start of the frame. The frame identification consists of a 31-bit bar code symbol plus 1 zero, the symbol sequence 0x "D12C 5E 3C".
The user address is 24 bits, and is a user identity identification address, and the user addresses are uniformly registered, distributed and managed by the central control system.
The address Check code is 6 bits, and Cyclic Redundancy Check (CRC) Check is performed on the user address.
The reserved bit is 1bit, the information bit is reserved, and the default is '0'.
The confirmation mark is 2bit, which represents the mode of the satellite for the user uplink confirmation applied by the frame, and the user uplink category is automatically filled by the user terminal according to the SIM (subscriber Identity Module) user Identity identification card parameter and the user uplink information category. Meanwhile, the master station comprehensively utilizes the identifier and other factors to select a branch of user downlink information X2b (Hexadecal to Binary). When the identification values are confirmed to be different, 4 conditions are provided, 00: the satellite does not need to carry out user uplink confirmation on the frame; 01: the satellite carries out user uplink confirmation on the frame in the user downlink I branch; 10: the satellite carries out user uplink confirmation on the frame in a user downlink Q branch; 11: and the satellite performs user uplink confirmation on the frame by uniformly selecting I, Q branches according to the downlink load condition of the X2 b.
The inbound satellite number is 6 bits, indicating the user uplink satellite that the user terminal automatically identifies as the Pseudo Random Noise code (PRN) number of the satellite.
The inbound sequence number is 5bit and is used for circularly marking the information number transmitted by the user in the uplink.
The priority is 1bit, indicating the user identity and the queuing priority. And for the user uplink information with the identification priority of '1', the access satellite and the master control station preferentially carry out forwarding processing. And the user terminal fills in according to the parameters of the SIM card.
The receiver type is 1bit, indicating the receiver address type in the data segment. 0 is the internal address of the Beidou system, and the word length of the receiving address is 24 bits; "1" is the external network address, and the word length of the receiving side address is 48 bit.
The bit length is 10 bits, indicating the bit length of the data segment, excluding CRC and tail.
The identity authentication is 22bit, and is used for the ground operation control system to perform identity authentication on the uplink user.
The information category is 8 bits and is used for representing the category of the information.
The user data is 660bit at the longest and is used for placing the user data.
The CRC is 16 bits and is used for CRC check.
The tail is 6 bit.
S1: and determining a primitive polynomial and an initial phase of the local short-period spread spectrum code according to the PRN number, the week count and the intra-week day count of the satellite.
Fig. 3 is a schematic flow chart of the on-line generation of spreading codes in an example of the present invention. Referring to fig. 3, in the present embodiment, the aperiodic long code spreading code is generated by using m-sequence, which is the simplest, most common, most widely used, and most easily implemented periodic pseudo-random sequence, and is fully called the longest linear feedback shift register sequence, and is also the basis for forming Gold sequence and m-sequence. Where the m-sequences are generated by linear shift registers. Fig. 4 is a schematic diagram of an r-stage linear shift register in one example of the invention. As shown in fig. 4, the recursive relationship of the feedback logic of the r-stage linear shift register is:
a i =c 1 a i-1+ c 2 a i-2+…+ c r a i-r
wherein the content of the first and second substances, a i （i=1,2, …, n) represents the state of each shift register,c i （i=1,2, …, n) represents a feedback coefficient of each shift register.
The r-th order polynomial corresponding to the feedback logic recurrence relation of the linear shift register is:
f（x）=c 0+ c 1 x+ c 2 x 2…+ c r x r
wherein the connection state of the feedback line is set byc i Is determined when the value of (0 or 1) is equal toc i When =1, it represents the feedback network and the secondiThe connection of the output of the stage shift register exists; when in usec i When =0, it represents the feedback network and the secondiNo connections for the stage shift register outputs exist. The r-degree polynomial and the feedback logic recursion relation are equivalent, and are two different expression methods of the feedback logic of the r-level shift register, and different expression methods can be applied to different occasions. If the period to be generated is 2 r 1 m sequence, and the structure of its r-stage shift register needs to be constructed, in which case the primitive polynomial of the m sequence can be determined first, and then the structure of the shift register can be constructed by referring to the primitive polynomial.
The m-sequence primitive polynomial is determined by removing all irreducible polynomials of degree r and then checking the resulting sequence for m-sequence using a trial-and-error approach over the remaining irreducible polynomials. If the test result is determined to be an m-sequence, then the polynomial is a primitive polynomial, otherwise it is not a primitive polynomial.
In detail, in this embodiment, the spreading code of the synchronization header adopts a short-period spreading code based on an 11-order m-sequence, the length of the spreading code is 2047 bits, and the length of one period is 1.25 ms. The generation of the spread spectrum code can be flexibly adjusted, the default spread spectrum code is not changed under the normal condition, the ground operation control system can uniformly set the generation of the satellite synchronization head spread spectrum code through a control instruction under the emergency condition, and the user uplink synchronization head spread spectrum code is generated through the synchronization head version number in the X2b signal. The input parameters of the synchronous head spread spectrum code generator are a satellite PRN number, the current Beidou cycle count, the intra-cycle second and a synchronous head version number, and the length is 43 bits in total. Wherein the PRN number occupies 6 bits, the week count occupies 13 bits, the second within the week occupies 20 bits, and the synchronization header version number is 4 bits. Where the sync header version number is signaled by X2 b. The initial phase of the spreading code generation depends on the initial phase of the shift register that produces the m-sequence, represented by a binary sequence of length 11 bits, ranging from 0x001 to 0x7 FF.
According to the indication of the synchronization header version number, the initial phase may be set to a fixed value when the sequence fixed mode is used; when using the sequential time varying mode, the initial phase can be calculated from the binary representation of the week count and the day of the week count.
In the present embodiment, the primitive polynomial includes a generator polynomial of a first m-sequence (denoted as an m1 sequence, hereinafter referred to as an m1 sequence) and a generator polynomial of a second m-sequence (denoted as an m2 sequence, hereinafter referred to as an m2 sequence).
Specifically, the generator polynomial of the m1 sequence may be expressed as:
g1=1+x 9+x 11+x 20+x 24
wherein g1 represents an m1 sequence,xthe power value of (a) corresponds to the series of the shift register. The initial phase of the m1 sequence is denoted as 0x "A76E 1A", initial phase: (c n c n-1… c 1) The lowest order bit of (a) represents the highest power.
The generator polynomial for the m2 sequence may be expressed as:
g2=1+x 3+x 6+x 19+x 24
where g2 denotes an m2 sequence, the initial phase of the m2 sequence depends on the sequence of inbound user addresses 24bit, and the lowest bits of the address code correspond to the lowest bits of the initial phase, i.e. to the highest power of the generator polynomial.
S2: and generating a periodic short code according to the primitive polynomial and the initial phase.
Specifically, the code stream can be converted into a binary code stream according to the formula expression of the primitive polynomial, wherein the power value of each term x in the formula corresponds to the digit of the binary number being 1, and other digits are only required to be complemented by 0, so that the periodic short code is obtained.
S3: and capturing burst frames according to the periodic short codes, and performing frame synchronization, namely using the periodic short codes to complete the de-spreading of symbols before frame identification (fields of service segments).
S4: an m1 sequence is generated from the primitive polynomial and the initial phase.
Fig. 5 is a diagram illustrating a structure of a spreading code of a subscriber uplink signal according to an example of the present invention. As shown in fig. 5, after the frame id synchronization is successful, an m1 sequence may be generated according to the generator polynomial of the m1 sequence, and the spreading code of the service segment from the "user address" field is represented by an m1 sequence.
S5: and processing the m1 sequence to obtain a decoding result of the user address.
Specifically, the local codes in the despreading module are despread by cutting short codes into m1 sequences, and the despreading results are demodulated and decoded in turn. Wherein the interpretation result of the user address in the service segment is used as the initial phase of the m2 sequence.
S6: and obtaining an m2 sequence according to the decoding result of the primitive polynomial and the user address.
Specifically, as seen from the user uplink signal frame structure, the frame identifies the remaining 156 symbols of the post-service segment, followed by the data segment. When the local symbol counter is accumulated to 156, the local m2 sequence online generation module generates an m2 sequence online according to the primitive polynomial given in the spreading code design scheme and the decoding result of the service segment user address.
S7: and generating the spreading codes of the data segments according to the first m sequence and the second m sequence.
Specifically, the Gold sequence is generated by modulo-2 addition of the m1 sequence and the m2 sequence, and data segment despreading is completed.
The following describes an aperiodic long-code spreading code generating device provided by the present invention, and the aperiodic long-code spreading code generating device described below and the aperiodic long-code spreading code generating method described above can be referred to in correspondence with each other.
Fig. 6 is a block diagram of a device for generating an aperiodic long-code spreading code according to the present invention. As shown in fig. 6, the apparatus for generating an aperiodic long-code spreading code according to the present invention includes: an acquisition module 610 and a control processing module 620.
The acquisition module 610 is configured to acquire the PRN number, week count, and intra-week day count of the satellite. The control processing module 620 is configured to determine a primitive polynomial and an initial phase of the local short-period spreading code according to the PRN number, the week count, and the intra-week day count of the satellite, and further generate the short-period code according to the primitive polynomial and the initial phase. The control processing module 620 is further configured to capture a burst frame through the obtaining module, and perform frame synchronization, where the burst frame includes a synchronization header, a service segment, and a data segment, which are connected in sequence. The control processing module 620 is further configured to generate an m1 sequence according to the primitive polynomial and the initial phase, and process the m1 sequence to obtain a decoding result of the user address. The control processing module 620 is further configured to obtain an m2 sequence according to the primitive polynomial and the decoding result of the user address, and generate a spreading code of the data segment according to the m1 sequence and the m2 sequence.
In one embodiment of the present invention, the control processing module 620 is further configured to define a user uplink signal frame protocol, so that the satellite generates the burst frame according to the user uplink signal frame protocol.
In one embodiment of the invention, the service segment comprises a precise heel, a frame identifier, a user address, an address check code, a reserved bit, a confirmation identifier, an inbound satellite number, an inbound serial number, a priority, a receiver type, a bit length indicator and identity authentication which are sequentially arranged. The data segment includes information categories, user data, cyclic redundancy check bits, and a tail.
In one embodiment of the invention, the m1 sequence is a spreading code from user address bits to tail bits, and the m2 sequence is a spreading code from information category bits to tail bits.
In an embodiment of the present invention, the control processing module 620 is configured to perform a modulo two addition operation on the m1 sequence and the m2 sequence to generate a Gold sequence, and the Gold sequence is used as a spreading code of the data segment.
In an embodiment of the present invention, the control processing module 620 is configured to despread, demodulate, and decode the m1 sequence sequentially to obtain a decoding result of the user address.
In one embodiment of the invention, the primitive polynomial includes a generator polynomial of a sequence m1 and a generator polynomial of a sequence m 2.
It should be noted that, a specific implementation of the apparatus for generating a aperiodic long-code spreading code according to the embodiment of the present invention is similar to a specific implementation of the method for generating a aperiodic long-code spreading code according to the embodiment of the present invention, and specific reference is specifically made to the description of the method for generating a aperiodic long-code spreading code, and details are not repeated for reducing redundancy.
In addition, other configurations and functions of the aperiodic long-code spreading code generating device according to the embodiment of the present invention are known to those skilled in the art, and are not described in detail for reducing redundancy.
Fig. 7 is a schematic diagram of the structure of an electronic device in one example of the invention. As shown in fig. 7, the electronic device may include: a central control processor 710, a communication interface 720, and a communication bus 730, wherein the central control processor is integrated with a memory that stores executable computer programs. The central control processor 710 and the communication interface 720 communicate with each other via a communication bus 730. The central control processor 710 may invoke logic instructions in memory to perform a method of generating an aperiodic long code spreading code, the method comprising: determining a primitive polynomial and an initial phase of a local short-period spread spectrum code according to a pseudo-random noise code (PRN) number, a week count and an intra-week day count of a satellite; generating a periodic short code according to the primitive polynomial and the initial phase; capturing burst frames according to the periodic short codes, and performing frame synchronization, wherein the burst frames comprise a synchronization head, a service section and a data section which are sequentially connected; generating an m1 sequence from the primitive polynomial and the initial phase; processing the m1 sequence to obtain a decoding result of the user address; obtaining an m2 sequence according to the primitive polynomial and the decoding result of the user address; generating spreading codes for the data segments according to the m1 sequence and the m2 sequence.
In the embodiment of the present invention, the central control processor may be an integrated circuit chip having signal processing capability. The central control Processor may be a general purpose Processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other Programmable logic device, discrete Gate or transistor logic device, discrete hardware component.
The various methods, steps and logic blocks disclosed in the embodiments of the present invention may be implemented or performed. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like. The steps of the method disclosed in connection with the embodiments of the present invention may be directly implemented by a hardware decoding processor, or implemented by a combination of hardware and software modules in the decoding processor. The software module may be located in ram, flash memory, rom, prom, or eprom, registers, etc. storage media as is well known in the art. The processor reads the information in the storage medium and completes the steps of the method in combination with the hardware.
In addition, the logic instructions in the memory may be implemented in the form of software functional units and may be stored in a computer readable storage medium when sold or used as a stand-alone product. 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 non-transitory computer-readable storage medium, on which a computer program is stored, the computer program being implemented by a processor to execute the methods for generating aperiodic long-code spreading codes provided in the above-mentioned respective aspects, the methods comprising: determining a primitive polynomial and an initial phase of a local short-period spread spectrum code according to a pseudo-random noise code (PRN) number, a week count and an intra-week day count of a satellite; generating a periodic short code according to the primitive polynomial and the initial phase; capturing burst frames according to the periodic short codes, and performing frame synchronization, wherein the burst frames comprise a synchronization head, a service section and a data section which are sequentially connected; generating an m1 sequence from the primitive polynomial and the initial phase; processing the m1 sequence to obtain a decoding result of the user address; obtaining an m2 sequence according to the primitive polynomial and the decoding result of the user address; generating spreading codes for the data segments according to the m1 sequence and the m2 sequence.
The storage medium may be a memory, for example, which may be volatile memory or nonvolatile memory, or which may include both volatile and nonvolatile memory.
The nonvolatile Memory may be a Read-Only Memory (ROM), a Programmable ROM (PROM), an Erasable PROM (EPROM), an Electrically Erasable PROM (EEPROM), or a flash Memory.
The volatile Memory may be a Random Access Memory (RAM) which serves as an external cache. By way of example and not limitation, many forms of RAM are available, such as Static random access memory (Static RAM, SRAM), Dynamic RAM (DRAM), Synchronous DRAM (SDRAM), Double Data Rate SDRAM (ddr Data Rate SDRAM), Enhanced SDRAM (ESDRAM), synchlink DRAM (SLDRAM), and Direct Rambus RAM (DRRAM).
The storage media described in connection with the embodiments of the invention are intended to comprise, without being limited to, these and any other suitable types of memory.
Those skilled in the art will appreciate that the functionality described in the present invention may be implemented in a combination of hardware and software in one or more of the examples described above. When software is applied, the corresponding functionality may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage media may be any available media that can be accessed by a general purpose or special purpose computer.
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.
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 (10)
1. A method for generating an aperiodic long code spreading code, comprising:
determining a primitive polynomial and an initial phase of a local short-period spread spectrum code according to a pseudo-random noise code (PRN) number, a week count and an intra-week day count of a satellite;
generating a periodic short code according to the primitive polynomial and the initial phase;
capturing burst frames generated according to a user uplink signal frame protocol according to the periodic short codes, and performing frame synchronization, wherein the burst frames comprise a synchronization head, a service section and a data section which are sequentially connected, and when a plurality of short frames need to be sent, a first frame meets the requirement of the minimum frame length by a carrier extension method and is called as the burst frame;
generating a first m-sequence according to the primitive polynomial and the initial phase;
processing the first m sequence to obtain a decoding result of the user address;
obtaining a second m sequence according to the primitive polynomial and the decoding result of the user address;
and generating the spread spectrum codes of the data segments according to the first m sequence and the second m sequence.
2. The method of claim 1, wherein prior to determining the primitive polynomial and initial phase of the local short-duration spreading code based on the PRN number week count and the intra-week day count of the satellite, further comprising:
and defining the user uplink signal frame protocol.
3. The method for generating an aperiodic long-code spread spectrum code according to claim 2, wherein the service segment comprises a precise tag, a frame identifier, a user address, an address check code, a reserved bit, a confirmation identifier, an inbound satellite number, an inbound serial number, a priority, a receiver type, a bit length indication and an identity authentication which are arranged in sequence; the data segment includes information category, user data, cyclic redundancy check bits, and a tail.
4. The method of claim 3, wherein the first m-sequence is a spreading code from the user address bits to the tail bits, and the second m-sequence is a spreading code from the information category bits to the tail bits.
5. The method of claim 4, wherein generating the spreading codes for the data segments based on the first m-sequence and the second m-sequence comprises:
and performing modulo-two addition operation on the first m sequence and the second m sequence to generate a Gold sequence, and using the Gold sequence as a spreading code of the data segment.
6. The method of claim 4, wherein the processing the first m-sequence to obtain a decoding result of the user address comprises:
and carrying out despreading, demodulation and decoding on the first m sequence in sequence to obtain a decoding result of the user address.
7. The method of claim 1, wherein the primitive polynomial comprises a generator polynomial of the first m-sequence and a generator polynomial of the second m-sequence.
8. An apparatus for generating an aperiodic long code spreading code, comprising:
the acquisition module is used for acquiring the PRN number, the week count and the intra-week day count of the satellite;
the control processing module is used for determining a primitive polynomial and an initial phase of a local short-period spread spectrum code according to the PRN number of the satellite, the week count and the intra-week day count, and further generating a period short code according to the primitive polynomial and the initial phase; the control processing module is further configured to capture, by the acquisition module, a burst frame generated according to a user uplink signal frame protocol, and perform frame synchronization, where the burst frame includes a synchronization header, a service segment, and a data segment that are sequentially connected, and when a plurality of short frames need to be sent, a first frame meets a requirement for a minimum frame length by a carrier extension method, and is referred to as the burst frame; the control processing module is further configured to generate a first m sequence according to the primitive polynomial and the initial phase, and process the first m sequence to obtain a decoding result of the user address; the control processing module is further configured to obtain a second m-sequence according to the primitive polynomial and the decoding result of the user address, and generate a spreading code of the data segment according to the first m-sequence and the second m-sequence.
9. An electronic device comprising a central control processor and a program stored on the central control processor, wherein the central control processor executes the program to implement the steps of the method for generating an aperiodic long code spreading code as recited in any one of claims 1 to 7.
10. A non-transitory computer readable storage medium, on which a program is stored, wherein the program, when executed by a processor, implements the steps of the method for generating an aperiodic long-code spreading code as recited in any one of claims 1 to 7.
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