CN112104440B

CN112104440B - Communication signal processing method and wireless communication system

Info

Publication number: CN112104440B
Application number: CN202010933624.4A
Authority: CN
Inventors: 龙必起
Original assignee: Shenzhen Huazhi Xinlian Technology Co ltd
Current assignee: Shenzhen Huazhi Xinlian Technology Co ltd
Priority date: 2020-09-08
Filing date: 2020-09-08
Publication date: 2021-05-11
Anticipated expiration: 2040-09-08
Also published as: CN112104440A

Abstract

The application relates to a communication signal processing method, a communication signal processing device, a communication signal processing apparatus, a communication signal processing system and a storage medium. The method comprises the following steps: carrying out forward error correction code processing on the transmitted information by adopting a preset forward error correction code to obtain at least one code word corresponding to the transmitted information and a code word index corresponding to each code word; the forward error correcting code is a low-density parity check code of a multilevel system; according to the code word index corresponding to each code word, carrying out multilevel cyclic shift spread spectrum modulation on each code word, and determining a multilevel cyclic shift spread spectrum code corresponding to each code word; the multi-system cyclic shift spread spectrum code is a spread spectrum code with any length; and carrying out radio frequency processing on the multi-system cyclic shift spread spectrum code corresponding to each code word, and sending the obtained radio frequency signal to a receiving end. The method can ensure that the length of the spread spectrum code obtained when the information is modulated and transmitted is not limited, namely the spread spectrum gain of the system is not limited.

Description

Communication signal processing method and wireless communication system

Technical Field

The present application relates to the field of communications technologies, and in particular, to a method, an apparatus, a device, a system, and a storage medium for processing a communication signal.

Background

In the field of communications, Direct Sequence Spread Spectrum (DSSS) refers to the encoding of one bit of data into a multi-bit Sequence, called a "chip". Compared with direct sequence spread spectrum, the multilevel modulation Cyclic Code-Shift spreading (CCSK) has the characteristics of high spectrum efficiency and excellent demodulation signal-to-noise ratio performance, and therefore is widely applied to the communication fields of satellite communication, internet of things communication, underwater acoustic communication, military communication and the like. Meanwhile, in order to improve the anti-noise performance in the communication process, before information is transmitted, a transmitting end modulates the transmitted information after adding a forward error correction code, and then transmits the modulated signal to a receiving end, and after the receiving end receives the signal, the receiving end can demodulate and decode the received signal, so that the transmitted information can be obtained.

In the related art, when the forward error correction code and the CCSK are used for transmitting information modulation, the decoding complexity of the receiving end is increased with the increase of the modulation carry number. Therefore, limited by the decoding complexity of the receiving end, the length of the spreading code of the modulation usually reaches a certain limit, for example, the spreading code of the same length is usually up to 64. As can be seen, the conventional technique has a problem that the length of the spreading code is limited when modulating the transmission information.

Disclosure of Invention

In view of the above, it is necessary to provide a communication signal processing method, apparatus, device, system, and storage medium that can make the length of a spreading code, i.e., the spreading gain, unlimited when modulating transmission information.

A method of communication signal processing, the method comprising:

carrying out forward error correction processing on the transmitted information by adopting a preset forward error correction code to obtain at least one code word corresponding to the transmitted information and a code word index corresponding to each code word; the forward error correcting code is a low density parity check code of a multilevel system;

according to the code word index corresponding to each code word, carrying out multilevel cyclic shift spread spectrum modulation on each code word, and determining a multilevel cyclic shift spread spectrum code corresponding to each code word; the multi-system cyclic shift spread spectrum code is a spread spectrum code with any length;

and carrying out radio frequency processing on the multi-system cyclic shift spread spectrum code corresponding to each code word, and sending the obtained radio frequency signal to a receiving end.

In one embodiment, the performing, according to the codeword index corresponding to each codeword, multilevel cyclic shift spread spectrum modulation on each codeword to determine a multilevel cyclic shift spread spectrum code corresponding to each codeword includes:

mapping each code word index to obtain a modulation index corresponding to each code word index; the modulation index is a corresponding cyclic shift value when the code word is modulated into the multi-system cyclic shift spread spectrum code;

and determining the multilevel cyclic shift spread spectrum code corresponding to each code word according to the modulation index corresponding to each code word index.

In one embodiment, the mapping each codeword index to obtain a modulation index corresponding to each codeword index includes:

acquiring the length of a multilevel cyclic shift spread spectrum code required to be modulated;

and according to each code word index, performing equal-interval upsampling on the length of the multi-system cyclic shift spread spectrum code to obtain a modulation index corresponding to each code word index.

In one embodiment, the determining the multilevel cyclic shift spreading code corresponding to each codeword according to the modulation index corresponding to each codeword index includes:

acquiring an initial multi-system cyclic shift spread spectrum code;

and according to the modulation index corresponding to each code word index, carrying out backward cyclic shift on the initial multilevel cyclic shift spread spectrum code by the size of each modulation index to obtain the multilevel cyclic shift spread spectrum code corresponding to each code word.

In one embodiment, the method further includes:

receiving radio frequency signals, and carrying out incoherent demodulation processing on the radio frequency signals to obtain a log-likelihood ratio corresponding to each code word;

carrying out reverse forward error correction code processing on the log-likelihood ratio corresponding to the code word to obtain an information bit corresponding to each code word;

and obtaining sending information according to the information bit corresponding to each code word.

In one embodiment, the performing non-coherent demodulation processing on the radio frequency signal to obtain a log likelihood ratio corresponding to each codeword includes:

carrying out incoherent demodulation processing on the radio-frequency signal by adopting a local multi-system cyclic shift spread spectrum code to obtain a plurality of correlation values corresponding to the radio-frequency signal;

according to the modulation index corresponding to each code word index, carrying out equally spaced down-sampling on a plurality of correlation values to obtain the correlation values with the number of a set system; the number of the set system is equal to the number of the code words;

and determining the maximum correlation value from the correlation values of the number of the set systems, and determining the log-likelihood ratio corresponding to each code word according to the correlation values of the number of the set systems and the maximum correlation value.

carrying out incoherent demodulation processing on the radio frequency signal by adopting a local multi-system cyclic shift spread spectrum code to obtain a plurality of correlation values corresponding to the radio frequency signal and modulation indexes corresponding to the correlation values respectively;

searching the maximum values of the plurality of correlation values to obtain the maximum correlation value and a position index of the maximum correlation value; performing mathematical operation processing on the position index of the maximum correlation value to obtain a target code word index corresponding to the position index of the maximum correlation value;

and obtaining the log-likelihood ratio corresponding to each code word according to the correlation value and the maximum correlation value of the set number, and setting the log-likelihood ratio at the position corresponding to the target code word index to be zero.

according to the code word index corresponding to each code word, carrying out multi-system cyclic shift spread spectrum modulation on each code word, and determining a cyclic shift spread spectrum code of a set system corresponding to each code word; the number of the set system is equal to the number of the code words;

and performing spread spectrum modulation again on the set-scale cyclic shift spread spectrum code corresponding to each code word, and determining the multilevel cyclic shift spread spectrum code corresponding to each code word.

In one embodiment, the method further includes:

receiving a radio frequency signal, and despreading the radio frequency signal by adopting a local spread spectrum sequence to obtain despreading symbols with a set system number;

carrying out incoherent demodulation processing on the de-spread symbols with the number of the set system to obtain a log-likelihood ratio corresponding to each code word;

A communication signal processing apparatus, the apparatus comprising:

the processing module is used for carrying out forward error correction code processing on the transmitted information by adopting a preset forward error correction code to obtain at least one code word corresponding to the transmitted information and a code word index corresponding to each code word; the forward error correcting code is a low density parity check code of a multilevel system;

the modulation module is used for carrying out multilevel cyclic shift spread spectrum modulation on each code word according to the code word index corresponding to each code word and determining a multilevel cyclic shift spread spectrum code corresponding to each code word; the multi-system cyclic shift spread spectrum code is a spread spectrum code with any length;

and the sending module is used for carrying out radio frequency processing on the multi-system cyclic shift spread spectrum code corresponding to each code word and sending the obtained radio frequency signal to a receiving end.

A computer device comprising a transceiver, a memory, and a processor, the memory storing a computer program,

when the processor executes the computer program, the processor is configured to perform forward error correction code processing on the transmission information by using a preset forward error correction code to obtain at least one codeword corresponding to the transmission information and a codeword index corresponding to each codeword; the forward error correcting code is a low density parity check code of a multilevel system;

when the processor executes the computer program, the processor is further configured to perform multilevel cyclic shift spread spectrum modulation on each codeword according to the codeword index corresponding to each codeword, and determine a multilevel cyclic shift spread spectrum code corresponding to each codeword; the multi-system cyclic shift spread spectrum code is a spread spectrum code with any length;

the transceiver is configured to perform radio frequency processing on the multilevel cyclic shift spreading code corresponding to each codeword, and send an obtained radio frequency signal to a receiving end.

A wireless communication system comprises a sending end and a receiving end, wherein the sending end and the receiving end can realize the steps of the method in the communication process.

A computer-readable storage medium, on which a computer program is stored which, when executed by a processor, carries out the steps of:

According to the communication signal processing method, the device, the equipment, the system and the storage medium, forward error correction code processing is carried out on the sending information by adopting the multilevel low-density parity check code to obtain the code word and the code word index corresponding to the sending information, multilevel cyclic shift spread spectrum modulation is carried out on each code word according to the code word index to obtain the multilevel cyclic shift spread spectrum code corresponding to each code word, and radio frequency processing are carried out on each multilevel cyclic shift spread spectrum code to be sent to the receiving end; the obtained multilevel cyclic shift spread spectrum code is a spread spectrum code with any length. In the method, when the code word is subjected to multilevel cyclic shift spread spectrum modulation by adopting the code word index, the obtained multilevel cyclic shift spread spectrum code is a spread spectrum code with any length, so that the length of the obtained multilevel cyclic shift spread spectrum code is not limited, the requirement of various scenes on the length of the spread spectrum code can be met, meanwhile, the complexity of system demodulation and decoding is not increased, namely, the complexity of a system receiving end is not increased, and the application range of the multilevel cyclic shift code is improved.

Drawings

FIG. 1 is a schematic diagram of a communication signal processing system in one embodiment;

FIG. 2 is a flow diagram illustrating a method for processing a communication signal according to one embodiment;

FIG. 3 is a flow chart illustrating steps of communication signal processing in another embodiment;

FIG. 3a is an exemplary diagram of modulation using index mapping in another embodiment;

FIG. 4 is a flow chart illustrating steps of processing a communication signal in another embodiment;

FIG. 4a is a diagram illustrating an example of a process for non-coherently demodulating a radio frequency signal in another embodiment;

FIG. 4b is an exemplary graph of the correlation values of the output of a matched filter in another embodiment;

FIG. 4c is a diagram illustrating a flow of LLR calculation in another embodiment;

FIG. 5 is a flow chart illustrating steps of processing a communication signal in another embodiment;

FIG. 5a is an exemplary diagram of modulation using quadratic spreading in another embodiment;

FIG. 6 is a block diagram showing the structure of a communication signal processing apparatus according to an embodiment;

FIG. 7 is a diagram illustrating an internal structure of a computer device according to an embodiment.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.

At present, when a forward error correction code and a cyclic shift spread spectrum CCSK of multilevel modulation are used for transmitting information modulation, the decoding complexity of a receiving end is continuously improved along with the continuous increase of modulation number. Therefore, limited by the decoding complexity of the receiving end, the length of the spreading code of the modulation usually reaches a certain limit, for example, the spreading code of the same length is usually up to 64. As can be seen, the conventional technique has a problem that the length of the spreading code is limited when modulating the transmission information. Therefore, embodiments of the present application provide a communication signal processing method, apparatus, device, system, and storage medium, which may solve the above technical problems.

The communication signal processing method provided in the embodiment of the present application may be applied to a communication signal processing system as shown in fig. 1, where the system includes a sending end 101 and a receiving end 102, and the sending end 101 and the receiving end 102 may perform uplink and downlink communication. The sending end 101 and the receiving end 102 are relative, taking downlink communication from a server to a terminal as an example, the sending end 101 may be a cloud server, a remote server, and the like, and the receiving end 102 may be various personal computers, notebook computers, smart phones, tablet computers, computer devices, and the like, and the specific forms of the sending end 101 and the receiving end 102 are not limited in this application. The transmitting end 101 may perform wireless or wired data transmission with the receiving end 102. Optionally, when performing communication between the sending end 101 and the receiving end 102, communication manners such as frequency division multiplexing, time division multiplexing, and code division multiplexing may be used.

The technical solution of the present application will be described in detail below with specific examples. The following several specific embodiments may be combined with each other, and details of the same or similar concepts or processes may not be repeated in some embodiments.

The execution subject of the method embodiments described below may be a communication signal processing system, a communication signal processing apparatus, a transmitting end, and a receiving end, and the execution subject is described below as an example of a communication signal processing system.

In an embodiment, a communication signal processing method is provided, and the embodiment relates to a specific process of how to perform error correction code processing and multilevel cyclic shift spread spectrum modulation on transmission information by using a multilevel low density parity check code to obtain a multilevel cyclic shift spread spectrum code with an arbitrary length. As shown in fig. 2, the method may include the steps of:

s202, carrying out forward error correction code processing on the transmitted information by adopting a preset forward error correction code to obtain at least one code word corresponding to the transmitted information and a code word index corresponding to each code word; the forward error correction code is a multilevel low density parity check code.

The adopted forward error correction code is a multilevel Low-density Parity check code (NB LDPC), which is called NB LDPC (Non-Binary Low-density Parity-check), that is, a Non-Binary LDPC, and here, the forward error correction code is adopted to perform error correction code processing on the transmitted information, which can improve the anti-noise performance of the communication signal processing system and improve the sensitivity performance of the receiving end. At present, binary LDPC is used more, the binary LDPC is a linear block forward error correction code close to a channel limit (shannon theoretical limit), and compared with the binary LDPC, NB LDPC has stronger error correction capability (especially when a code length is short), a lower error rate platform, faster decoding convergence, and is more suitable for high-order modulation/multilevel modulation, so that the NB LDPC is mainly used for performing the forward error correction code to process transmission information in the embodiment of the present application.

In addition, Forward Error Correction (FEC) processing refers to that a transmitting end adds a certain redundant Error Correction code to data to be transmitted and transmits the data, and a receiving end decoder performs Error detection on the data according to the Error Correction code, and if an Error is found, the receiving end decoder corrects the Error.

Specifically, after obtaining the transmission information to be transmitted to the receiving end, the transmitting end of the communication signal processing system may perform forward error correction code processing on the transmission information by using an NB LDPC code, that is, encode the transmission information, so that the processed codewords and the index corresponding to each codeword may be obtained and recorded as codeword indexes. In addition, the codeword obtained here may be one codeword or multiple codewords, and the obtained codeword may be q elements or symbols in a high-order galois field gf (q), and may be α, for example⁰、α¹And so on. Each codeword can be represented by p bits, and can also be indexed by decimal codeword (x)_kE {0,1, …, q-1}, k being 0,1, …, q-1), where q is 2^pQ is generally 64 or less, and p is generally 6 or less.

S204, according to the code word index corresponding to each code word, performing multilevel cyclic shift spread spectrum modulation on each code word, and determining a multilevel cyclic shift spread spectrum code corresponding to each code word; the multilevel cyclic shift spreading code is a spreading code with any length.

In this step, after obtaining the codeword index corresponding to each codeword, a multilevel cyclic shift spreading code with length N (where N is an arbitrary number, which can be expressed by the power N of 2, and N is a natural number) that needs to be modulated to transmit information can be obtained at the same time, and then the codeword can be modulated into the multilevel cyclic shift spreading code with length N by mapping the codeword index to the index of the multilevel spreading code.

Of course, it is also possible to directly perform CCSK multilevel cyclic shift spread spectrum modulation on each codeword through the codeword index of each codeword to obtain a spread spectrum code with the same number of levels and the same length as the codewords, and then perform secondary spreading on the obtained spread spectrum code to obtain a cyclic shift spread spectrum code with the length of N. It should be noted that the cyclic shift spreading code with the length N obtained in this way is not a cyclic shift spreading code in a strict sense, and is essentially a spreading code with the length N obtained by performing secondary spreading on cyclic shift spreading codes with the length equal to the number of code words and then concatenating a plurality of spread spreading codes after spreading.

Of course, the cyclic shift spreading code with the multilevel length N corresponding to each codeword may also be obtained by other manners, and in short, each codeword may be modulated into the spreading code with the multilevel length N by performing the multilevel cyclic shift spreading modulation on each codeword.

Based on this, the embodiments of the present application can be applied to spreading code modulation of any length, for example, 32 length, 64 length, 256 length, 1024 length, and so on.

It should be noted that the embodiments of the present application are mainly applied to modulating transmission information into a cyclic shift spreading code with a length of 64 or more. The code words are modulated into the spreading codes with larger length, the complexity is not improved too much, and therefore the noise resistance of the system can be better in the communication process, namely the communication performance is better, and meanwhile the power consumption of the system can be reduced.

And S206, performing radio frequency processing on the multi-system cyclic shift spread spectrum code corresponding to each code word, and sending the obtained radio frequency signal to a receiving end.

In this step, after obtaining the multilevel cyclic shift spreading codes corresponding to each codeword, all the multilevel cyclic shift spreading codes may be input to the front end of the transmitting digital for upsampling and filtering, and digital-to-analog conversion (DAC) is performed on the signal after filtering, and then the signal after digital-to-analog conversion may be sent to the radio frequency transmitter for upconversion to obtain a radio frequency signal, and then the radio frequency signal may be sent to the receiving end to complete signal transmission.

In the communication signal processing method, a multilevel low-density parity check code is adopted to perform forward error correction code processing on the transmitted information to obtain a code word and a code word index corresponding to the transmitted information, multilevel cyclic shift spread spectrum modulation is performed on each code word according to the code word index to obtain a multilevel cyclic shift spread spectrum code corresponding to each code word, and radio frequency processing are performed on each multilevel cyclic shift spread spectrum code to be transmitted to a receiving end; the obtained multilevel cyclic shift spread spectrum code is a spread spectrum code with any length. In the method, when the code word is subjected to multilevel cyclic shift spread spectrum modulation by adopting the code word index, the obtained multilevel cyclic shift spread spectrum code is a spread spectrum code with any length, so that the length of the obtained multilevel cyclic shift spread spectrum code is not limited, the requirement of various scenes on the length of the spread spectrum code can be met, meanwhile, the complexity of system demodulation and decoding is not increased, namely, the complexity of a system receiving end is not increased, and the application range of the multilevel cyclic shift code is improved.

In another embodiment, another communication signal processing method is provided, and this embodiment relates to a possible implementation manner of how to perform multilevel cyclic shift spread spectrum modulation on a codeword by using a codeword index to obtain a multilevel cyclic shift spread spectrum code. On the basis of the above embodiment, as shown in fig. 3, the above S204 may include the following steps:

s302, mapping each code word index to obtain a modulation index corresponding to each code word index; the modulation index is a cyclic shift value corresponding to the modulation of the code word into the multilevel cyclic shift spread spectrum code.

In this step, see fig. 3a, which is an exemplary diagram of modulation using index mapping. The codeword index corresponding to each codeword may be x_kDenotes x_kE {0,1, …, q-1}, k ═ 0,1, …, q-1, in mapping each codeword index to a modulation index, optionally, the following steps may be adopted for mapping: acquiring the length of a multilevel cyclic shift spread spectrum code required to be modulated; and according to each code word index, performing equal-interval upsampling on the length of the multi-system cyclic shift spread spectrum code to obtain a modulation index corresponding to each code word index.

That is, before each codeword is subjected to spread spectrum modulation, a spreading code of what length each codeword needs to be modulated into, i.e., the original spreading code, can be obtained in advance, and thus the length to be modulated can be obtained. Taking the spreading sequence with length N as an example, the original spreading code can be represented as C₀＝[c(0)c(1)…c(N-2)c(N-1)]It can be seen that the original spreading code comprises N chips, where N is usually equal to or greater than q, e.g., q is 64, N can be 128, 256, 1024, etc.

When mapping the codeword indexes, there is usually one-to-one mapping, that is, one codeword index is mapped to obtain one modulation index, and the modulation index is y_kDenotes y_k＝x_k·2^m，y_kE {0,1, …, N-1}, k being 0,1, …, q-1. It can be seen that the range of modulation indices is compared to x before_kThe range of (b) is enlarged, so that sampling can be carried out within the range of N length to obtain sampling points with the same number as q, the number corresponding to each sampling point is the modulation index, and the method can also be used forA shift value of several bits is required to shift with an original spreading code called N length.

When the above-mentioned sampling is performed within the range of N length, the sampling may be performed at equal intervals, for example, N is 1024, and the sampling may be performed once every 16 intervals, that is, each codeword index is multiplied by 16 to obtain a modulation index; of course, non-equal-interval sampling may also be adopted, for example, N is 1024, the first codeword index is sampled once at an interval of 2, the second codeword index is sampled once at an interval of 4, and so on, that is, the first codeword is multiplied by 2 to obtain a corresponding modulation index, the second codeword is multiplied by 4 to obtain a corresponding modulation index, and the other codewords may be analogized in turn; of course, other non-equal-interval sampling manners may also be adopted, and in short, the modulation index corresponding to each codeword index may be obtained by sampling within the range of N.

It should be noted that, in the present embodiment, equal-interval sampling is mainly adopted, so that when channel damage occurs in the subsequent signal transmission process, the communication performance and the anti-noise performance of the system can be better ensured.

S304, according to the modulation index corresponding to each code word index, determining the multilevel cyclic shift spread spectrum code corresponding to each code word.

In this step, when the modulation index is used to obtain the multilevel cyclic shift spreading code, optionally, the initial multilevel cyclic shift spreading code may be obtained; and according to the modulation index corresponding to each code word index, carrying out backward cyclic shift on the initial multilevel cyclic shift spread spectrum code by the size of each modulation index to obtain the multilevel cyclic shift spread spectrum code corresponding to each code word.

Taking the obtained original spreading code as an example, for an original spreading code with a length of N, the original spreading code may be circularly shifted backward by the size of the modulation index according to the modulation index corresponding to each codeword index, so that a multilevel cyclic shift spreading code corresponding to each modulation index may be obtained, and the length of each multilevel cyclic shift spreading code is N. When a spreading code with a length of N is cyclically shifted, N different cyclically shifted spreading codes can be obtained.

Illustratively, a spreading code of length N may be represented by the following equation (1), as follows:

C_j＝[c(j)c((j+1)％N)…c((j+N-2)％N)c((j+N-1)％N)] (1)

where j is a cyclic shift value corresponding to the modulation index, for example, the modulation index is 0, and then j is 0, i.e. the original spreading code, C₀＝[c(0)c(1)…c(N-2)c(N-1)](ii) a For example, the modulation index is 8, then j is 8, i.e. the obtained multilevel cyclic shift spreading code is C₈＝[c(8)c((8+1)％N)…c((8+N-2)％N)c((8+N-1)％N)]。

In short, the above method can be used according to j ═ y_kAnd as a cyclic shift value, obtaining a code set consisting of q cyclic shift spread codes, and performing q-ary CCSK modulation, namely outputting a spread code with the code length of N or N spread sequences/spread symbols to obtain a multilevel cyclic shift spread code with the length of N corresponding to each code word.

After obtaining the multilevel cyclic shift spreading code corresponding to each codeword, the spreading gain of the multilevel cyclic shift spreading modulation CCSK can also be calculated.

It is assumed here that N is q · 2^m＝2^p·2^m＝2^SFWherein q is the number of the code word, p is the number of bits when each code word is represented by bits, m is a spreading factor, generally greater than 1, and SF is a spreading factor. Thus, the spreading gain PG of the q-ary CCSK can be expressed by the following formula (2):

generally, the gain of the conventional q-ary CCSK modulation is qp, and thus, the spreading gain of the q-ary CCSK modulation in the present embodiment is increased by 2 compared to the conventional modulation method^mAnd different m can be obtained according to different N, namely the spread spectrum gain is not limited.

For example, using q-64, p-6, m-4, SF-10, and N-1024 as examples, an equal-interval upsampling index mapping (interval 16) is used, which is further described below with reference to table 1. In table 1, the first column is 64 codewords/symbols of NB LDPC in GF (64) domain, the second column is represented by bits of the codewords, the third column is codeword indexes (decimal representation), the fourth column is modulation indexes after mapping, and the fifth column is a multilevel cyclic shift spreading code corresponding to the modulation indexes, that is, CCSK sequence. Table 1 is as follows:

TABLE 1

In this embodiment, each codeword index is mapped to obtain a corresponding modulation index, and a multilevel cyclic shift spreading code is obtained through the modulation index, where the modulation index is a cyclic shift value corresponding to when the codeword is modulated into the multilevel cyclic shift spreading code. By the method, the code words can be modulated into the spread spectrum codes with any length simply, and the decoding complexity of the receiving end can not be increased, so that the decoding performance of the receiving end can be ensured, and the system power consumption can not be increased.

In another embodiment, another communication signal processing method is provided, and this embodiment relates to a possible implementation of how the receiving end decodes the received signal for a modulation scheme such as index mapping. On the basis of the above embodiment, as shown in fig. 4, the method may further include the following steps:

s402, receiving radio frequency signals, and carrying out incoherent demodulation processing on the radio frequency signals to obtain a log likelihood ratio corresponding to each code word.

In this step, after the receiving end can receive the radio frequency signal sent by the sending end, the receiving end can perform digital front-end processing on the received radio frequency signal and then perform signal synchronization processing, and after the signal synchronization is completed, perform incoherent demodulation on the synchronized signal, where the received signal usually includes a transmitted signal and noise, and then the incoherent demodulation here can be regarded as demodulating the transmitted signal from the received signal. Optionally, the following steps a1-A3 may be used for non-coherent demodulation:

step A1, performing incoherent demodulation processing on the radio frequency signal by using a local multi-system cyclic shift spreading code to obtain a plurality of correlation values corresponding to the radio frequency signal.

Step A2, according to the modulation index corresponding to each code word index, sampling a plurality of correlation values at equal intervals to obtain the correlation values with the number of the set system; the number of the above-mentioned setting scale is equal to the number of the code words.

Step a3, determining the maximum correlation value from the correlation values of the set number of bins, and determining the log-likelihood ratio corresponding to each codeword according to the correlation values of the set number of bins and the maximum correlation value.

After the synchronized signal is obtained, the synchronized signal may be input to a matched filter for non-coherent demodulation in steps a 1-A3. In the matched filter, all correlation values corresponding to the synchronization signal can be calculated, then a required correlation value is selected according to the corresponding multi-system cyclic shift spread spectrum code of each code word, and a Log-Likelihood Ratio (Log-Likelihood Ratio) is calculated according to the correlation values.

The matched filter may be a frequency-domain matched filter or a time-domain matched filter, and taking the frequency-domain matched filter as an example, the process of performing incoherent demodulation may be as shown in fig. 4a, wherein a synchronized signal is first fourier-FFT transformed into a frequency domain and then is matched with a local multilevel cyclic shift spreading code C₀And performing conjugate multiplication on the frequency domain signals subjected to FFT, performing inverse Fourier transform (IFFT) on the multiplied signals to convert the multiplied signals to a time domain, finally performing module value taking on the time domain signals, and selecting q correlation values according to an index mapping relation, wherein the number of the correlation values is equal to the number of the code words. For example, when the equal-interval upsampling index mapping is used, and the equal-interval downsampling is performed, the correlation values at 64 positions, i.e., 0, 16, 32, 48, …, and 1008, can be selected from the matched filter output according to the table 1, and the total of 64 correlation values are obtained.

After the selected correlation values are obtained, a maximum correlation value among the selected correlation values may be selected, and then an LLR may be calculated using the maximum correlation value. When calculating LLR, generally, the correlation value of the local spreading code currently calculating LLR minus the correlation value of any local spreading code may be used, and this calculation method is relatively random and inconvenient to calculate in the actual calculation process, so for convenience of calculation and realizability here, two preferable methods are given when calculating LLR of each spreading code.

One is to select the correlation value of the first local spreading code in each local spreading code to participate in the calculation, for example, according to the following formula (3):

wherein Z is [ Z ]₀,z₁,...,z_N-1]For a received spreading symbol (including the transmitted multilevel cyclic shift spreading code and noise); n is the length of the local multi-system cyclic shift spread spectrum code and is equal to the length of the transmitted spread spectrum code; i is the sequence number of the chip in the local multi-system cyclic shift spreading code, i.e. the several chips of the local spreading code.

Here, the correlation function is defined as

The above equation (3) can be expressed by the following equation (4):

the other is to select the maximum correlation value CMax in the correlation values of the local spread spectrum codes corresponding to the spread spectrum codes to participate in the calculation, and the calculation formula can be used

And (4) showing.

Further, in this embodiment, it is mainly adopted that the maximum correlation value CMax participates in the calculation, and then the LLR corresponding to the received spreading code may be obtained by selecting the maximum correlation value from the multiple correlation values corresponding to the spreading code and subtracting the maximum correlation value from the multiple selected correlation values, where the maximum value of the LLR is 0, and the local spreading code corresponding to the position where the LLR is 0 is the spreading code sent by the sending end. By doing so for each received spreading code, each multilevel cyclic shift spreading code sent by the sending end can be demodulated.

Further, before the correlation values are sampled and selected at equal intervals from the plurality of correlation values output by the matched filter, whether the maximum correlation value in the plurality of correlation values has position drift or not can be judged, and the correlation value selection is performed under the condition that the position drift meets the condition, so that the condition that the maximum correlation value is missed or detected can be ensured, the accuracy of the selected correlation value is improved, namely the accuracy of the calculated LLR is improved, and the accuracy of the finally demodulated spread spectrum code can be ensured. In combination with this situation, another non-coherent demodulation manner is given below, and optionally, the step S402 may perform non-coherent demodulation by using the following steps B1-B4:

and step B1, performing incoherent demodulation processing on the radio frequency signal by using a local multi-system cyclic shift spread spectrum code to obtain a plurality of correlation values corresponding to the radio frequency signal and modulation indexes corresponding to the correlation values respectively.

Step B2, carrying out maximum value search on the multiple correlation values to obtain a maximum correlation value and a position index of the maximum correlation value; and performing mathematical operation processing on the position index of the maximum correlation value to obtain a target code word index corresponding to the position index of the maximum correlation value.

Step B3, according to the modulation index corresponding to each code word index, sampling the multiple correlation values at equal intervals to obtain the correlation values with the number of the set system; the number of the above-mentioned setting scale is equal to the number of the code words.

And step B4, obtaining the log-likelihood ratio corresponding to each code word according to the correlation value and the maximum correlation value of the set number, and setting the log-likelihood ratio at the position corresponding to the target code word index as zero.

In steps B1-B4, the above situation of generating position drift is explained below, for example, referring to FIG. 4B, when the modulation index y₂32(k is 2, i.e. y)_k＝y₂) When y is above₂The maximum value of the correlation value (correlation peak) of the corresponding multilevel cyclic shift spreading code should appear at 32 positions of the matched filter output, as shown in (b) of fig. 4 b. In a multi-path channel, such as a two-path channel, a similar correlation peak may occur at another location (as shown in fig. 4b (c)). In addition, when the synchronization time at the receiving end drifts, the position of the correlation peak also drifts to other positions accordingly (as shown in (d) of fig. 4 b). When the correlation value is selected by the above-mentioned equidistant down-sampling method, in the case of multipath channel or synchronization drifting, the maximum value of missed detection is likely to occur in the selected LLR correlation value peaks, including the case of multipath channel (as shown in (c) of fig. 4 b), and the LLR value output at the position "32" may be the next largest correlation value; when the synchronization drifts (as shown in (d) of fig. 4 b), the LLR value output at position "32" may be a slight noise value. When either of the above two cases occurs, the decoding performance of the NB LDPC deteriorates.

Therefore, before the above-mentioned downsampling at equal intervals, the maximum search is performed on all correlation values output from the matched filter to find a correlation peak value, i.e. a maximum correlation value; as long as the position of the correlation peak shifts<2^m-1The above-described case of missing detection can be avoided, and thus deterioration of the NB LDPC decoding performance can be avoided. The specific detection flow is shown in fig. 4 c. The first step, searching out the maximum correlation value (CMax) and the position index idx thereof from all correlation values output by a matched filter; second, calculating the target code word index

round () is rounded; when drifting<2^m-1Rounding off guarantees the target codeword index

The accuracy of the obtained maximum correlation value can be ensured; thirdly, sampling and extracting a set number of correlation values at equal intervals, for example, 64 correlation values; step four, subtracting CMax from all correlation values; the fifth step, at the target code word index

The position sets the LLR value to the maximum value "0". Taking the matched filter to obtain 1024 correlation values as an example, where the position index of the maximum correlation value refers to the position number of the searched maximum correlation value in the 1024 correlation values, i.e. at the several bits of the 1024 correlation values, for example, the position index of the maximum correlation value may be 36 in the graph (c) in fig. 4b, 29 in the graph (d) in fig. 4b, and so on.

S404, performing reverse forward error correction code processing on the log-likelihood ratio corresponding to the code word to obtain the information bit corresponding to each code word.

Specifically, after the LLR value corresponding to each codeword in the received signal is obtained, the local multilevel cyclic shift code corresponding to the position of the maximum LLR value may be subjected to inverse forward error correction processing, that is, decoding or decoding processing, so that the information bit corresponding to each codeword may be obtained, that is, the transmission information is recovered.

S406, obtaining sending information according to the information bit corresponding to each code word.

Specifically, after the information bits corresponding to each codeword are obtained, the obtained information bits may be directly used as the transmission information.

In this embodiment, the radio frequency signal may be received, and the radio frequency signal may be subjected to incoherent demodulation to obtain a log likelihood ratio, and subjected to inverse forward error correction code processing to obtain an information bit, so as to recover the transmission information. By the method of the embodiment, the receiving end can recover the transmitted information more simply, so that the decoding complexity of the receiving end can be reduced, and the overall power consumption of the system can be reduced.

In another embodiment, another communication signal processing method is provided, and this embodiment relates to another possible implementation manner of how to perform multilevel cyclic shift spread spectrum modulation on a codeword by using a codeword index to obtain a multilevel cyclic shift spread spectrum code and recover transmitted information. On the basis of the above embodiment, as shown in fig. 5, the above S204 may include the following steps:

s502, according to the code word index corresponding to each code word, performing multi-system cyclic shift spread spectrum modulation on each code word, and determining a cyclic shift spread spectrum code of a set system corresponding to each code word; the number of the above-mentioned setting scale is equal to the number of the code words.

In this step, see fig. 5a, which is an exemplary diagram of modulation using secondary spreading. If the obtained index of each codeword is, for example, q-ary codeword index as described above, then q-ary codeword index x can be obtained_kAnd sending the signal into a q-ary CCSK modulator, and outputting a CCSK sequence/code/symbol with the spreading symbol length of q. The length of the obtained multilevel cyclic shift spread spectrum code, i.e. the CCSK code, is the same as the scale of the code word index, for example, the 64-scale code word index, and then the 64-scale CCSK code is obtained here.

And S504, performing spread spectrum modulation again on the set-scale cyclic shift spread spectrum code corresponding to each code word, and determining the multilevel cyclic shift spread spectrum code corresponding to each code word.

In this step, after obtaining the CCSK code corresponding to each codeword, another spreading code may be used to perform secondary spreading on each CCSK code, where the spreading code may be represented as: d ═ D (0) D (1) … D (2)^m-1)]Where D is the spreading code, m is the same as above, a spreading factor, and D () is the chips in the spreading code.

Specifically, in the case of secondary spreading, taking a CCSK code as an example, the CCSK code may be multiplied by each chip in D and concatenated into a length N q · 2^mAnd obtaining the multilevel cyclic shift spread spectrum code with the length of N corresponding to each code word. In this way, all CCSK codes can be spread secondarily, so that a length N multi-system cyclic shift spread code after each CCSK code is spread secondarily can be obtained.

Can be calculated from the aboveHere too, the spreading gain is

I.e. an extension of the spreading gain can be achieved as well.

It should be noted that, as mentioned in S204 above, the cyclic shift spreading code with length N obtained in this way is not a cyclic shift spreading code in the strict sense, and is essentially obtained by spreading the cyclic shift spreading code with length q obtained after CCSK spreading modulation twice to obtain 2^mQ spreading codes, and 2^mAnd the spreading codes with the length of N are obtained by cascading the spreading codes with the length of q.

In addition, when D is a full "1" sequence, then when obtaining the multilevel cyclic shift spreading code, it is the CCSK code repetition 2^mThen, the multi-system cyclic shift spread spectrum code corresponding to the CCSK code can be obtained.

For example, assume a CCSK code as [ a, b, c, d]，D＝[1，-1，1，-1]When the CCSK code is spread twice, a b c d is multiplied by 1, -1, 1, -1 to obtain a b c d, -a-b-c-d, a b c d, -a-b-c-d, and then the codes are concatenated to obtain a b c d-a-b-c-d a b c d-a-b-c-d, which is the multilevel cyclic shift spreading code corresponding to the CCSK code. It can be seen that the length before is 4 and the length after spreading is 16, the spreading gain is increased by 2²。

After the secondary spreading mode is used for spreading, the spread code after spreading may also be subjected to radio frequency processing and sent to the receiving end, and then the receiving end may perform despreading and demodulation after receiving the signal, optionally, the following steps B1-B4 may be used:

and step B1, receiving the radio frequency signal, and despreading the radio frequency signal by using a local spreading sequence to obtain despreading symbols with the set number.

And step B2, carrying out non-coherent demodulation processing on the de-spread symbols with the set number of the carry system to obtain the log-likelihood ratio corresponding to each code word.

And step B3, performing reverse forward error correction code processing on the log-likelihood ratio corresponding to the code word to obtain the information bit corresponding to each code word.

And step B4, obtaining the sending information according to the information bit corresponding to each code word.

In steps B1-B4, after receiving the signal, the receiving end first performs secondary despreading, i.e. recovering the CCSK spreading codes. During secondary despreading, each chip of a local multi-system cyclic shift spreading code can be adopted to repeat q times and then multiplied by a received signal, and then q chips are separated for accumulation, so that q secondary despreading symbols of CCSK can be obtained. Here, the number of symbols after secondary despreading is equal to the number of CCSK codes during modulation, and may be 64, for example.

After the two-stage despread symbols are obtained, the two-stage despread symbols may be input to a matched filter corresponding to the CCSK code for non-coherent demodulation processing to obtain q correlation values, a maximum correlation value may be selected from the q correlation values, and the maximum correlation value is subtracted from the q correlation values, so as to obtain an LLR corresponding to each two-stage despread symbol, that is, an LLR corresponding to each codeword, from which a maximum LLR value may also be obtained. Here, the maximum LLR value is also 0.

Then, the local multi-system cyclic shift code corresponding to the position of the maximum LLR value can be subjected to inverse forward error correction code processing, that is, decoding processing, so that the information bit corresponding to each codeword can be obtained, that is, the transmission information is recovered.

In this embodiment, each codeword may be subjected to multilevel cyclic shift spread spectrum modulation through the codeword index to obtain a cyclic shift spread spectrum code of a set scale, and secondary spread spectrum is performed to obtain a multilevel cyclic shift spread spectrum code. By the spread spectrum mode, the code words can be expanded into spread spectrum codes with any order values or any length more simply, so that the decoding complexity of a receiving end can be reduced, and the power consumption of a system is further reduced.

To facilitate understanding of those skilled in the art, the communication signal processing method provided in the present application is described in detail below with reference to two specific embodiments, one is index mapping spread spectrum modulation, and the other is quadratic spread spectrum modulation, which are described below:

firstly, the method of index mapping spread spectrum modulation may include the following steps:

s1, carrying out forward error correction code processing on the transmitted information by adopting a preset forward error correction code to obtain at least one code word corresponding to the transmitted information and a code word index corresponding to each code word.

And S2, obtaining the length of the multi-system cyclic shift spread spectrum code to be modulated.

And S3, according to each code word index, performing equal-interval upsampling on the length of the multilevel cyclic shift spread spectrum code to obtain a modulation index corresponding to each code word index.

And S4, acquiring the initial multi-system cyclic shift spread spectrum code.

And S5, according to the modulation index corresponding to each code word index, the initial multilevel cyclic shift spread spectrum code is circularly shifted backwards by the size of each modulation index, and the multilevel cyclic shift spread spectrum code corresponding to each code word is obtained.

And S6, receiving the radio frequency signal, and performing incoherent demodulation processing on the radio frequency signal by using a local multi-system cyclic shift spread spectrum code to obtain a plurality of correlation values corresponding to the radio frequency signal.

S7, according to the modulation index corresponding to each code word index, carrying out equally spaced down sampling on a plurality of correlation values to obtain the correlation values with the number of the set system; the number of the above-mentioned setting scale is equal to the number of the code words.

S9, determining the maximum correlation value from the correlation values of the set number of bins, and determining the log-likelihood ratio corresponding to each codeword according to the correlation values of the set number of bins and the maximum correlation value.

S10, carrying out reverse forward error correction code processing on the log-likelihood ratio corresponding to the code word to obtain the information bit corresponding to each code word; and obtaining sending information according to the information bit corresponding to each code word.

Secondly, a mode of secondary spread spectrum modulation, the method can comprise the following steps:

and D1, performing forward error correction code processing on the transmission information by using a preset forward error correction code to obtain at least one code word corresponding to the transmission information and a code word index corresponding to each code word.

And D2, performing multilevel cyclic shift spread spectrum modulation on each code word according to the code word index corresponding to each code word, and determining the cyclic shift spread spectrum code of the set scale corresponding to each code word.

D3, performing spread spectrum modulation again on the set-scale cyclic shift spreading code corresponding to each code word, and determining the multilevel cyclic shift spreading code corresponding to each code word.

And D4, receiving the radio frequency signal, and despreading the radio frequency signal by using a local spreading sequence to obtain despreading symbols with the set number.

D5, carrying out non-coherent demodulation processing on the de-spread symbols with the number of the set system to obtain the log-likelihood ratio corresponding to each code word;

d6, performing reverse forward error correction code processing on the log-likelihood ratio corresponding to the code word to obtain the information bit corresponding to each code word; and obtaining sending information according to the information bit corresponding to each code word.

It should be understood that although the various steps in the flow charts of fig. 2-5 are shown in order as indicated by the arrows, the steps are not necessarily performed in order as indicated by the arrows. The steps are not performed in the exact order shown and described, and may be performed in other orders, unless explicitly stated otherwise. Moreover, at least some of the steps in fig. 2-5 may include multiple steps or multiple stages, which are not necessarily performed at the same time, but may be performed at different times, which are not necessarily performed in sequence, but may be performed in turn or alternately with other steps or at least some of the other steps.

In one embodiment, as shown in fig. 6, there is provided a communication signal processing apparatus including: processing module 10, modulation module 11 and sending module 12, wherein:

a processing module 10, configured to perform forward error correction code processing on the transmission information by using a preset forward error correction code, so as to obtain at least one codeword corresponding to the transmission information and a codeword index corresponding to each codeword; the forward error correcting code is a low density parity check code of a multilevel system;

the modulation module 11 is configured to perform multilevel cyclic shift spread spectrum modulation on each codeword according to a codeword index corresponding to each codeword, and determine a multilevel cyclic shift spread spectrum code corresponding to each codeword; the multi-system cyclic shift spread spectrum code is a spread spectrum code with any length;

and a sending module 12, configured to perform radio frequency processing on the multilevel cyclic shift spreading code corresponding to each codeword, and send an obtained radio frequency signal to a receiving end.

For specific limitations of the communication signal processing apparatus, reference may be made to the above limitations of the communication signal processing method, which are not described herein again.

In another embodiment, another communication signal processing apparatus is provided, and on the basis of the above embodiment, the modulation module 11 may include an index mapping unit and a first modulation unit, where:

the index mapping unit is used for mapping each code word index to obtain a modulation index corresponding to each code word index; the modulation index is a corresponding cyclic shift value when the code word is modulated into the multi-system cyclic shift spread spectrum code;

and the first modulation unit is used for determining the multilevel cyclic shift spread spectrum code corresponding to each code word according to the modulation index corresponding to each code word index.

Optionally, the index mapping unit may include a length obtaining subunit and an upsampling subunit, where:

a length obtaining subunit, configured to obtain a length of a multilevel cyclic shift spreading code to be modulated;

and the up-sampling subunit is used for performing equal-interval up-sampling on the length of the multilevel cyclic shift spread spectrum code according to each code word index to obtain a modulation index corresponding to each code word index.

Optionally, the first modulation unit may include an initial code obtaining subunit and a cyclic shift subunit, where:

an initial code obtaining subunit, configured to obtain an initial multilevel cyclic shift spreading code;

and the cyclic shift subunit is used for performing backward cyclic shift on the initial multilevel cyclic shift spread code by the size of each modulation index according to the modulation index corresponding to each code word index to obtain the multilevel cyclic shift spread code corresponding to each code word.

In another embodiment, another communication signal processing apparatus is provided, on the basis of the above embodiment, the apparatus may further include a first receiving module, a first demodulating module, a first inverse error correction processing module, and a first transmission information recovering module, where:

the first receiving module is used for receiving radio frequency signals;

the first demodulation module is used for carrying out incoherent demodulation processing on the radio frequency signal to obtain a log likelihood ratio corresponding to each code word;

the first inverse error correction processing module is used for performing inverse forward error correction processing on the log likelihood ratio corresponding to the code word to obtain an information bit corresponding to each code word;

and the first transmitted information recovery module is used for obtaining transmitted information according to the information bit corresponding to each code word.

Optionally, the first demodulation module may include a demodulation unit, a down-sampling unit, and a log-likelihood ratio determination unit, where:

the demodulation unit is used for carrying out incoherent demodulation processing on the radio-frequency signal by adopting a local multi-system cyclic shift spread spectrum code to obtain a plurality of correlation values corresponding to the radio-frequency signal;

the down-sampling unit is used for performing equal-interval down-sampling on a plurality of correlation values according to the modulation index corresponding to each code word index to obtain the correlation values with the number of the set system; the number of the set system is equal to the number of the code words;

and a log-likelihood ratio determining unit for determining a maximum correlation value from the correlation values of the number of the set numbers, and determining a log-likelihood ratio corresponding to each codeword according to the correlation values of the number of the set numbers and the maximum correlation value.

Optionally, the first demodulation module may include a demodulation unit, a maximum value determination unit, a codeword index calculation unit, a downsampling unit, and a log-likelihood ratio determination unit, where:

a demodulation unit, configured to perform incoherent demodulation processing on the radio frequency signal by using a local multilevel cyclic shift spreading code to obtain multiple correlation values corresponding to the radio frequency signal and modulation indexes corresponding to the multiple correlation values;

a maximum value determining unit, configured to perform maximum value search on the multiple correlation values to obtain a maximum correlation value and a position index of the maximum correlation value;

the code word index calculating unit is used for performing mathematical operation processing on the position index of the maximum correlation value to obtain a target code word index corresponding to the position index of the maximum correlation value;

and the log-likelihood ratio determining unit is used for obtaining the log-likelihood ratio corresponding to each code word according to the correlation value and the maximum correlation value of the set system number, and setting the log-likelihood ratio at the position corresponding to the target code word index as zero.

In another embodiment, another communication signal processing apparatus is provided, and on the basis of the above embodiment, the modulation module 11 may include a second modulation unit and a second spread spectrum modulation unit, wherein:

the second modulation unit is used for carrying out multilevel cyclic shift spread spectrum modulation on each code word according to the code word index corresponding to each code word and determining a cyclic shift spread spectrum code of a set scale corresponding to each code word; the number of the set system is equal to the number of the code words;

and the secondary spread spectrum modulation unit is used for carrying out secondary spread spectrum modulation on the set-scale cyclic shift spread spectrum code corresponding to each code word and determining the multi-scale cyclic shift spread spectrum code corresponding to each code word.

Optionally, the apparatus may further include a second receiving module, a despreading module, a second demodulating module, a second inverse error correction processing module, and a second transmitted information recovering module, where:

the second receiving module is used for receiving the radio frequency signal;

the despreading module is used for despreading the radio frequency signal by adopting a local spread spectrum sequence to obtain despreading symbols with the quantity of a set system;

the second demodulation module is used for carrying out incoherent demodulation processing on the de-spread symbols with the number of the set system to obtain the log-likelihood ratio corresponding to each code word;

the second inverse error correction processing module is used for performing inverse forward error correction processing on the log likelihood ratio corresponding to the code word to obtain the information bit corresponding to each code word;

and the second sent information recovery module is used for obtaining the sent information according to the information bit corresponding to each code word.

The respective modules in the communication signal processing apparatus described above may be wholly or partially implemented by software, hardware, and a combination thereof. The modules can be embedded in a hardware form or independent from a processor in the computer device, and can also be stored in a memory in the computer device in a software form, so that the processor can call and execute operations corresponding to the modules.

In one embodiment, a computer device is provided, where the computer device may be a server or a terminal, and an internal structure diagram of the computer device may be as shown in fig. 7, taking the server as an example. The computer device includes a transceiver, a processor, a memory, and a network interface connected by a system bus. Wherein the transceiver of the computer device is used to send and receive communication signals. The processor is used to provide computing and control capabilities. The memory of the computer device comprises a nonvolatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operation of an operating system and computer programs in the non-volatile storage medium. The database of the computer device is used for storing communication signal processing data. The network interface of the computer device is used for communicating with an external terminal through a network connection. The computer program is executed by a processor to implement a communication signal processing method.

Those skilled in the art will appreciate that the architecture shown in fig. 7 is merely a block diagram of some of the structures associated with the disclosed aspects and is not intended to limit the computing devices to which the disclosed aspects apply, as particular computing devices may include more or less components than those shown, or may combine certain components, or have a different arrangement of components.

In one embodiment, there is provided a computer device comprising a transceiver, a memory, and a processor, the memory having stored therein a computer program,

In one embodiment, the processor, when executing the computer program, further performs the steps of:

mapping each code word index to obtain a modulation index corresponding to each code word index; the modulation index is a corresponding cyclic shift value when the code word is modulated into the multi-system cyclic shift spread spectrum code; and determining the multilevel cyclic shift spread spectrum code corresponding to each code word according to the modulation index corresponding to each code word index.

acquiring the length of a multilevel cyclic shift spread spectrum code required to be modulated; and according to each code word index, performing equal-interval upsampling on the length of the multi-system cyclic shift spread spectrum code to obtain a modulation index corresponding to each code word index.

acquiring an initial multi-system cyclic shift spread spectrum code; and according to the modulation index corresponding to each code word index, carrying out backward cyclic shift on the initial multilevel cyclic shift spread spectrum code by the size of each modulation index to obtain the multilevel cyclic shift spread spectrum code corresponding to each code word.

In one embodiment, the transceiver is further configured to receive a radio frequency signal; when the processor executes the computer program, the processor is further configured to perform incoherent demodulation processing on the radio frequency signal to obtain a log-likelihood ratio corresponding to each codeword; carrying out reverse forward error correction code processing on the log-likelihood ratio corresponding to the code word to obtain an information bit corresponding to each code word; and obtaining sending information according to the information bit corresponding to each code word.

carrying out incoherent demodulation processing on the radio-frequency signal by adopting a local multi-system cyclic shift spread spectrum code to obtain a plurality of correlation values corresponding to the radio-frequency signal; according to the modulation index corresponding to each code word index, carrying out equally spaced down-sampling on a plurality of correlation values to obtain the correlation values with the number of a set system; the number of the set system is equal to the number of the code words; and determining the maximum correlation value from the correlation values of the number of the set systems, and determining the log-likelihood ratio corresponding to each code word according to the correlation values of the number of the set systems and the maximum correlation value.

carrying out incoherent demodulation processing on the radio frequency signal by adopting a local multi-system cyclic shift spread spectrum code to obtain a plurality of correlation values corresponding to the radio frequency signal and modulation indexes corresponding to the correlation values respectively; searching the maximum values of the plurality of correlation values to obtain the maximum correlation value and a position index of the maximum correlation value; performing mathematical operation processing on the position index of the maximum correlation value to obtain a target code word index corresponding to the position index of the maximum correlation value; according to the modulation index corresponding to each code word index, carrying out equally spaced down-sampling on a plurality of correlation values to obtain the correlation values with the number of a set system; the number of the set system is equal to the number of the code words; and obtaining the log-likelihood ratio corresponding to each code word according to the correlation value and the maximum correlation value of the set number, and setting the log-likelihood ratio at the position corresponding to the target code word index to be zero.

according to the code word index corresponding to each code word, carrying out multi-system cyclic shift spread spectrum modulation on each code word, and determining a cyclic shift spread spectrum code of a set system corresponding to each code word; the number of the set system is equal to the number of the code words; and performing spread spectrum modulation again on the set-scale cyclic shift spread spectrum code corresponding to each code word, and determining the multilevel cyclic shift spread spectrum code corresponding to each code word.

In one embodiment, the transceiver is further configured to receive a radio frequency signal; when the processor executes the computer program, the processor is further configured to despread the radio frequency signal by using a local spreading sequence to obtain despread symbols of a set number; carrying out incoherent demodulation processing on the de-spread symbols with the number of the set system to obtain a log-likelihood ratio corresponding to each code word; carrying out reverse forward error correction code processing on the log-likelihood ratio corresponding to the code word to obtain an information bit corresponding to each code word; and obtaining sending information according to the information bit corresponding to each code word.

In one embodiment, a computer-readable storage medium is provided, having a computer program stored thereon, which when executed by a processor, performs the steps of:

In one embodiment, the computer program when executed by the processor further performs the steps of:

receiving radio frequency signals, and carrying out incoherent demodulation processing on the radio frequency signals to obtain a log-likelihood ratio corresponding to each code word; carrying out reverse forward error correction code processing on the log-likelihood ratio corresponding to the code word to obtain an information bit corresponding to each code word; and obtaining sending information according to the information bit corresponding to each code word.

receiving a radio frequency signal, and despreading the radio frequency signal by adopting a local spread spectrum sequence to obtain despreading symbols with a set system number; carrying out incoherent demodulation processing on the de-spread symbols with the number of the set system to obtain a log-likelihood ratio corresponding to each code word; carrying out reverse forward error correction code processing on the log-likelihood ratio corresponding to the code word to obtain an information bit corresponding to each code word; and obtaining sending information according to the information bit corresponding to each code word.

It will be understood by those skilled in the art that all or part of the processes of the methods of the embodiments described above can be implemented by hardware instructions of a computer program, which can be stored in a non-volatile computer-readable storage medium, and when executed, can include the processes of the embodiments of the methods described above. Any reference to memory, storage, database or other medium used in the embodiments provided herein can include at least one of non-volatile and volatile memory. Non-volatile Memory may include Read-Only Memory (ROM), magnetic tape, floppy disk, flash Memory, optical storage, or the like. Volatile Memory can include Random Access Memory (RAM) or external cache Memory. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM), among others.

The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. A method of communication signal processing, the method comprising:

carrying out forward error correction code processing on the transmitted information by adopting a preset forward error correction code to obtain at least one code word corresponding to the transmitted information and a code word index corresponding to each code word; the forward error correcting code is a low-density parity check code of a multilevel system;

performing radio frequency processing on the multi-system cyclic shift spread spectrum code corresponding to each code word, and sending the obtained radio frequency signal to a receiving end;

wherein, the performing, according to the codeword index corresponding to each codeword, multilevel cyclic shift spread spectrum modulation on each codeword to determine the multilevel cyclic shift spread spectrum code corresponding to each codeword includes:

according to the code word index corresponding to each code word, carrying out multilevel cyclic shift spread spectrum modulation on each code word, and determining a cyclic shift spread spectrum code of a set level corresponding to each code word; the number of the set systems is equal to the number of the code words;

2. The method according to claim 1, wherein said performing, according to a codeword index corresponding to each codeword, multilevel cyclic shift spread spectrum modulation on each codeword to determine a multilevel cyclic shift spread spectrum code corresponding to each codeword comprises:

mapping each code word index to obtain a modulation index corresponding to each code word index; the modulation index is a corresponding cyclic shift value when the code word is modulated into a multi-system cyclic shift spread spectrum code;

determining a multilevel cyclic shift spread spectrum code corresponding to each code word according to the modulation index corresponding to each code word index;

wherein the mapping each codeword index to obtain a modulation index corresponding to each codeword index includes:

and according to each code word index, performing equal-interval upsampling on the length of the multilevel cyclic shift spread spectrum code to obtain a modulation index corresponding to each code word index.

3. The method according to claim 2, wherein said determining the multilevel cyclic shift spreading code corresponding to each of the codewords according to the modulation index corresponding to each of the codeword indexes comprises:

acquiring an initial multi-system cyclic shift spread spectrum code;

4. A method according to any one of claims 2 to 3, characterized in that the method further comprises:

receiving the radio frequency signal, and performing incoherent demodulation processing on the radio frequency signal to obtain a log-likelihood ratio corresponding to each code word;

performing reverse forward error correction code processing on the log-likelihood ratio corresponding to the codeword to obtain an information bit corresponding to each codeword;

and obtaining the sending information according to the information bit corresponding to each code word.

5. The method of claim 4, wherein said non-coherently demodulating said radio-frequency signal to obtain a log-likelihood ratio corresponding to each of said codewords comprises:

carrying out incoherent demodulation processing on the radio frequency signal by adopting a local multi-system cyclic shift spread spectrum code to obtain a plurality of correlation values corresponding to the radio frequency signal;

according to the modulation index corresponding to each code word index, carrying out equally spaced down-sampling on the plurality of correlation values to obtain correlation values with the number of a set system; the number of the set systems is equal to the number of the code words;

and determining a maximum correlation value from the correlation values of the number of the set systems, and determining a log-likelihood ratio corresponding to each code word according to the correlation values of the number of the set systems and the maximum correlation value.

6. The method of claim 4, wherein said non-coherently demodulating said radio-frequency signal to obtain a log-likelihood ratio corresponding to each of said codewords comprises:

performing incoherent demodulation processing on the radio frequency signal by adopting a local multi-system cyclic shift spread spectrum code to obtain a plurality of correlation values corresponding to the radio frequency signal and modulation indexes corresponding to the correlation values respectively;

searching the maximum values of the plurality of correlation values to obtain the maximum correlation value and the position index of the maximum correlation value; performing mathematical operation processing on the position index of the maximum correlation value to obtain a target code word index corresponding to the position index of the maximum correlation value;

and obtaining the log-likelihood ratio corresponding to each code word according to the correlation value of the set system number and the maximum correlation value, and setting the log-likelihood ratio at the position corresponding to the target code word index as zero.

7. The method of claim 1, further comprising:

receiving the radio frequency signal, and despreading the radio frequency signal by adopting a local spread spectrum sequence to obtain despreading symbols with the quantity of the set system;

8. A communication signal processing apparatus, characterized in that the apparatus comprises:

the processing module is used for carrying out forward error correction code processing on the transmitted information by adopting a preset forward error correction code to obtain at least one code word corresponding to the transmitted information and a code word index corresponding to each code word; the forward error correcting code is a low-density parity check code of a multilevel system;

a modulation module, configured to perform multilevel cyclic shift spread spectrum modulation on each codeword according to a codeword index corresponding to each codeword, and determine a multilevel cyclic shift spread spectrum code corresponding to each codeword; the multi-system cyclic shift spread spectrum code is a spread spectrum code with any length;

the transmitting module is used for carrying out radio frequency processing on the multi-system cyclic shift spread spectrum code corresponding to each code word and transmitting an obtained radio frequency signal to a receiving end;

wherein the modulation module comprises:

a second modulation unit, configured to perform multilevel cyclic shift spread spectrum modulation on each codeword according to a codeword index corresponding to each codeword, and determine a set-level cyclic shift spread spectrum code corresponding to each codeword; the number of the set systems is equal to the number of the code words;

and the secondary spread spectrum modulation unit is used for carrying out secondary spread spectrum modulation on the set-scale cyclic shift spread spectrum code corresponding to each code word and determining the multilevel cyclic shift spread spectrum code corresponding to each code word.

9. A computer device comprising a transceiver, a memory and a processor, the memory storing a computer program,

when the processor executes the computer program, the processor is configured to perform forward error correction code processing on transmission information by using a preset forward error correction code to obtain at least one codeword corresponding to the transmission information and a codeword index corresponding to each codeword; the forward error correcting code is a low-density parity check code of a multilevel system;

when the processor executes the computer program, the processor is further configured to perform multilevel cyclic shift spread spectrum modulation on each codeword according to a codeword index corresponding to each codeword, and determine a multilevel cyclic shift spread spectrum code corresponding to each codeword; the multi-system cyclic shift spread spectrum code is a spread spectrum code with any length;

the transceiver is used for carrying out radio frequency processing on the multi-system cyclic shift spread spectrum code corresponding to each code word and sending an obtained radio frequency signal to a receiving end;

when the processor executes the computer program, the processor is further configured to perform multilevel cyclic shift spread spectrum modulation on each codeword according to a codeword index corresponding to each codeword, and determine a set-level cyclic shift spread spectrum code corresponding to each codeword; the number of the set systems is equal to the number of the code words; and performing spread spectrum modulation again on the set-scale cyclic shift spread spectrum code corresponding to each code word, and determining the multilevel cyclic shift spread spectrum code corresponding to each code word.

10. A wireless communication system comprising a transmitting end and a receiving end, wherein the transmitting end and the receiving end can implement the steps of the method of any one of claims 1 to 7 during communication.

11. A computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, is characterized by the steps of the method of any one of claims 1 to 7.