CN113644980B

CN113644980B - Code modulation, demodulation decoding method, device and storage medium

Info

Publication number: CN113644980B
Application number: CN202010345412.4A
Authority: CN
Inventors: 李威; 黄勤; 吴志航; 梁伟光
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2020-04-27
Filing date: 2020-04-27
Publication date: 2022-11-18
Anticipated expiration: 2040-04-27
Also published as: CN113644980A

Abstract

The application discloses a coding modulation, demodulation and decoding method, a coding modulation, demodulation and decoding device, a storage medium method, a storage medium device and a storage medium, and belongs to the technical field of optical communication. The method comprises the following steps: the transmitter can encode the first bit stream according to a target encoding mode to obtain a second bit stream, then adjust the second bit stream according to a modulation mapping rule to obtain an X polarization symbol stream and a Y polarization symbol stream, further perform electro-optical modulation on the X polarization symbol stream and the Y polarization symbol stream to generate a double-polarization signal, and send the double-polarization signal to the receiver. The target coding mode is determined according to a code space, and the code space is determined according to a Stokes constraint condition, a code distance constraint condition and a modulation mapping rule, so that the code space can meet the Stokes constraint condition to resist a nonlinear effect, and can also meet the code distance constraint condition, the fault tolerance of the system is improved, the overall transmission performance of the system is better, and a receiver can receive a higher-quality double-polarized signal.

Description

Code modulation, demodulation decoding method, device and storage medium

Technical Field

The present application relates to the field of optical communication technologies, and in particular, to a method, an apparatus, and a storage medium for encoding, modulating, demodulating, and decoding.

Background

A fiber optic communication system is comprised primarily of a transmitter, a physical channel, and a receiver, where the physical channel is comprised primarily of fiber optic links. In long-distance transmission, in order to make the optical signal received by the receiver have a certain signal-to-noise ratio, an erbium-doped fiber amplifier (EDFA) is generally used in the optical fiber link to maintain the transmitted optical signal at a certain optical power. Usually one optical signal corresponds to two polarized optical fields, denoted as S _x And S _y If the amplitude E of the two polarized light fields _x And E _y Instability or poor orthogonality of the two polarized light fields can cause mutual interference between the two polarized light fields, and nonlinear effects can be generated in the optical fiber link. If the power of the added light exceeds a certain threshold, the nonlinear effect generated in the optical fiber link is intensifiedResulting in serious interference to the optical signal, affecting the quality of the received optical signal, and causing limitation to the transmission performance of the system.

In the related art, since the stokes vector can represent the polarization state information of the optical signal, a constraint condition for improving the transmission performance of the system can be designed based on the stokes vector. For example, constraint 1 requires | E to be as large as possible _x | ² +|E _y | ² The amplitude of the optical signal is kept constant to resist certain nonlinear effects, and constraint 2 needs to make the polarization state to assume an equilibrium state as much as possible to resist cross polarization modulation (XPolM) in the nonlinear effects, that is, make the sum of stokes vectors of the optical signals of each time slot in a continuous time be a zero vector. In order to satisfy the two constraints, a coding modulation scheme based on polarization multiplexed-quadrature phase shift keying (PM-QPSK) is adopted, and PM-QPSK is a modulation mode with constant amplitude, namely, can satisfy constraint 1, and has good capability of resisting nonlinear effect. In addition, in the scheme, two consecutive time slots transmit 8 bits in total after encoding, the constraint condition 2 is that the sum of stokes vectors of optical signals of the two consecutive time slots is zero vector, and there are 2^6 code words with the length of 8 which satisfy the constraint condition 2, so that any 6-bit sequence can be uniquely mapped to one code word with the length of 8 which satisfies the condition, that is, the consecutive 6-bit sequence before encoding can be encoded to obtain an 8-bit sequence which satisfies the constraint condition, the 6-bit sequence before encoding is information bits, and 8 bits after encoding are obtained, which is equivalent to redundant bits with 2 bits, so that the highest code rate of the scheme is 6/8.

However, in general, when the code rate exceeds 4/8, the minimum code distance of the code space will rapidly become small, i.e., the higher the code rate, the smaller the minimum code distance. In the above scheme, the code rate is 6/8, the minimum code distance of the code space is 2, the fault tolerance of the system is very low, and the performance of coded modulation will deteriorate rapidly, so that the transmission performance of the system cannot reach the overall best performance.

Disclosure of Invention

The application provides a code modulation, demodulation and decoding method, a device and a storage medium, which can resist the nonlinear effect and improve the fault tolerance of a system so as to improve the overall transmission performance of the system. The technical scheme is as follows:

in a first aspect, a coded modulation method is provided, and the method includes:

a transmitter acquires a first bit stream; the transmitter encodes the first bit stream according to a target encoding mode to obtain a second bit stream, wherein the target encoding mode is determined according to a code space, and the code space is determined according to a Stokes constraint condition, a code distance constraint condition and a modulation mapping rule; the transmitter modulates the second bit stream according to a modulation mapping rule to obtain an X polarization symbol stream and a Y polarization symbol stream; the transmitter electro-optically modulates the X-polarization symbol stream and the Y-polarization symbol stream to generate a dual-polarization signal, and transmits the dual-polarization signal.

Therefore, the code space in the application can meet the Stokes constraint condition to resist the nonlinear effect, and the code space can also meet the code distance constraint condition to improve the fault tolerance of the system, so that the overall transmission performance of the system is better, and thus, after the double-polarized light signals sent by the transmitter are transmitted through the optical fiber link, the receiver can receive the double-polarized light signals with higher quality.

In this application, a transmitter encodes a first bit stream according to a target coding scheme, including: and when the transmitter acquires continuous k bits in the first bit stream, once coding the continuous k bits according to a target coding mode to obtain a code word, wherein the code word comprises N bits, k and N are integers which are larger than 0, and k is smaller than N.

Optionally, one code space may correspond to one or more coding modes, and the target coding mode is one of the one or more coding modes.

Optionally, the modulation mapping rule is determined based on QPSK, N is an integer multiple of 8, and each of the X-polarization symbol stream and the Y-polarization symbol stream includes a plurality of consecutive N/4 slots.

It should be noted that one symbol of QPSK may be represented by two bits, at least two consecutive slots included in the X-polarization symbol stream and the Y-polarization symbol stream obtained after modulation need to satisfy the stokes constraint condition, and as two consecutive slots included in the X-polarization symbol stream and the Y-polarization symbol stream may be represented by 4 symbols, in this way, two consecutive slots included in the X-polarization symbol stream and the Y-polarization symbol stream correspond to 8 bits, and therefore, N may be an integer multiple of 8. In other embodiments, the modulation mapping rule may also be determined based on any other modulation scheme, so that the value of N may also need to be changed accordingly.

In this application, after obtaining the X-polarization symbol stream and the Y-polarization symbol stream, the transmitter may add light to the X-polarization symbol stream and the Y-polarization symbol stream to perform electro-optical modulation, so as to generate a dual-polarization signal, that is, convert a digital signal into an analog signal. Then, the receiver can send the double-polarized light signal to the receiver through an optical fiber link, so that the double-polarized light field obtained after electro-optical modulation can carry light source information to be transmitted to the receiver.

Alternatively, in the present application, in case that the modulation mapping rule is determined based on QPSK, k may be equal to 9,N may be equal to 16, and the code distance constraint condition means that the minimum code distance of the code space is 4. Therefore, the nonlinear effect can be resisted, and the fault tolerance of the system is improved, so that the overall transmission performance of the system is improved.

Optionally, the present application provides two stokes constraints, where the first stokes constraint means that the sum of the stokes vectors of the optical signals of two adjacent time slots in N/4 consecutive time slots is zero vector.

Assuming that k equals 9,N equals 16, the x-polarization symbol stream and the Y-polarization symbol stream include a plurality of consecutive 4 slots, the 4 slots are T1, T2, T3, and T4 in sequence, and the stokes vectors of the optical signals corresponding to the slots T1, T2, T3, and T4 are S1, S2, S3, and S4, respectively, the stokes constraint condition may be:

in the present application, different concepts and tools may be used for the same code space. In order to quickly determine the code space satisfying the condition, the code space may be determined in a manner described by a coset leader.

Optionally, the code space is determined according to a first formula;

the first formula is:

wherein, in the first formula, W is a code space, v _i Refers to a coset leader of length N for describing code space, N refers to v _i The number of (A), K is the nuclear space, and

wherein u is _j Is a row vector of length 6, m refers to u _j M equals 2 to the power of 6, G is the generator matrix.

v _i ∈V，V＝V ^(p) ∪V ^(q) ；

The above formula V = V ^(p) ∪V ^(q) P =1,q =2, or p =3,q =4, or p =1,q =4, or p =2,q =3.

After the calculation, four code spaces, namely a code space I, a code space II, a code space III and a code space IV can be determined and obtained, wherein the code space I is according to the V ⁽¹⁾ And V ⁽²⁾ Determined, code space two is according to the above V ⁽³⁾ And V ⁽⁴⁾ Determined, code space three is according to V above ⁽¹⁾ And V ⁽⁴⁾ Determined that the code space four is according to V ⁽²⁾ And V ⁽³⁾ And (4) determining.

It should be noted that, in the present application, there may be more than one coding mode in the same code space, and the selection of information bits in different coding modes may be different.

Optionally, the second stokes constraint condition means that the sum of stokes vectors of optical signals of two adjacent time slots before and after the odd time slot in N/4 consecutive time slots is zero vector, and the stokes vectors of optical signals of two adjacent time slots before and after the even time slot are perpendicular to each other.

in order to quickly determine the code space satisfying the condition, the code space may be determined in a manner described by a coset leader, and optionally, the code space is according to the first formula

Determining; wherein, the first and the second end of the pipe are connected with each other,

v _i ∈V，V＝V ^(p) ∪V ^(q) ；

the above formula V = V ^(p) ∪V ^(q) P =5,q =6, or p =7,q =8, or p =5,q =8, or p =6,q =7.

After the calculation, four code spaces can be determined and obtained, namely a code space five, a code space six, a code space seven and a code space eight, wherein the code space five is according to the V ⁽⁵⁾ And V ⁽⁶⁾ Determining that code space six is according to V above ⁽⁷⁾ And V ⁽⁸⁾ Defining a code space seven according to V ⁽⁵⁾ And V ⁽⁸⁾ Determined that code space eight is according to V above ⁽⁶⁾ And V ⁽⁷⁾ And (4) determining.

As can be seen from the above description, the determined code spaces may be different according to different stokes constraints, and the corresponding coding modes of each code space are also different.

In a second aspect, a demodulation and decoding method is provided, the method including:

the receiver receives a double-polarized light signal, wherein the double-polarized light signal is determined according to a target coding mode and a modulation mapping rule, the target coding mode is determined according to a code space, and the code space is determined according to a Stokes constraint condition, a code distance constraint condition and the modulation mapping rule; the receiver processes the double-polarization signal to obtain an X polarization symbol stream and a Y polarization symbol stream; and the receiver demodulates and decodes the X polarization symbol stream and the Y polarization symbol stream according to a target demodulation decoding mode to obtain a first bit stream, wherein the target demodulation decoding mode is determined according to a target coding mode and a modulation mapping rule.

It should be noted that the target coding scheme, the code space, and the modulation mapping rule are the same as those described in the foregoing first aspect, and the method for determining the target coding scheme and the code space may refer to the related description in the foregoing embodiment, and are not described herein again.

Therefore, the code space in the application can meet the Stokes constraint condition to resist the nonlinear effect, and the code space can also meet the code distance constraint condition to improve the fault-tolerant capability of the system, so that the overall transmission performance of the system is better, and the receiver can receive the double-polarization signal with higher quality.

In this application, the receiver may use a single-frequency continuous light source to mix with the dual-polarized light signal, and convert the mixed dual-polarized light signal into an electrical digital signal through the analog-to-digital converter and the sampler, and then send the electrical digital signal to the DSP module for digital signal processing, such as equalization and filtering, to obtain the X-polarized symbol stream and the Y-polarized symbol stream.

In this application, after recovering the X-polarization symbol stream and the Y-polarization symbol stream, the receiver may demodulate and decode the X-polarization symbol stream and the Y-polarization symbol stream according to a target demodulation and decoding manner to obtain a first bit stream.

Optionally, the target demodulation and decoding manner includes a target demodulation manner and a target decoding manner, the target demodulation manner is determined according to the modulation and mapping rule, and the target decoding manner is determined according to the target encoding manner; the receiver demodulates and decodes the X polarization symbol stream and the Y polarization symbol stream according to a target demodulation and decoding mode to obtain a first bit stream, and the method comprises the following steps: the receiver demodulates the X polarization symbol stream and the Y polarization symbol stream according to a target demodulation mode to obtain a second bit stream; and the receiver decodes the second bit stream according to the target decoding mode to obtain the first bit stream. That is, the receiver may perform the demodulation operation and then the decoding operation to recover the first bit stream.

Optionally, the decoding, by the receiver, the second bit stream according to the target decoding manner includes: and when the receiver acquires continuous N bits in the second bit stream, decoding the continuous N bits once according to a target decoding mode to obtain an information sequence, wherein the information sequence comprises k bits, k and N are integers greater than 0, and k is smaller than N.

Optionally, the target demodulation and decoding manner is used to indicate a mapping relationship between a polarization symbol sequence and an information sequence, where the polarization symbol sequence refers to a symbol subsequence included in an X-polarization symbol stream and a Y-polarization symbol stream, and the information sequence refers to a bit subsequence included in a first bit stream; the receiver demodulates and decodes the X polarization symbol stream and the Y polarization symbol stream according to a target demodulation decoding mode to obtain a first bit stream, and the method comprises the following steps: and the receiver demodulates and decodes the X polarization symbol stream and the Y polarization symbol stream according to the mapping relation to obtain a first bit stream. That is, the receiver may perform a mapping operation once to recover the first bit stream.

In a third aspect, a coded modulation apparatus is provided, which has a function of implementing the coded modulation method behavior in the first aspect. The code modulation apparatus includes one or more modules, and the one or more modules are configured to implement the code modulation method provided in the first aspect.

That is, the present application provides a code modulation apparatus applied to a transmitter, the apparatus comprising:

an obtaining module, configured to obtain a first bitstream;

the coding module is used for coding the first bit stream according to a target coding mode to obtain a second bit stream, wherein the target coding mode is determined according to a code space, and the code space is determined according to a Stokes constraint condition, a code distance constraint condition and a modulation mapping rule;

the modulation module is used for modulating the second bit stream according to the modulation mapping rule to obtain an X polarization symbol stream and a Y polarization symbol stream;

and the sending module is used for performing electro-optical modulation on the X polarization symbol stream and the Y polarization symbol stream to generate a double-polarization signal and sending the double-polarization signal.

Optionally, the encoding module is specifically configured to:

and each time k continuous bits in the first bit stream are obtained, once coding is carried out on the k continuous bits according to a target coding mode to obtain a code word, wherein the code word comprises N bits, k and N are integers which are larger than 0, and k is smaller than N.

Optionally, the code space corresponds to one or more coding modes, and the target coding mode is one of the one or more coding modes.

Alternatively, k equals 9,N equals 16, and the code distance constraint means that the minimum code distance of the code space is 4.

Optionally, the stokes constraint condition means that the sum of stokes vectors of optical signals of two adjacent time slots in the consecutive N/4 time slots is a zero vector.

Optionally, the stokes constraint condition means that the sum of stokes vectors of optical signals of two time slots immediately after the odd time slot and the even time slot in the consecutive N/4 time slots is zero vector, and the stokes vectors of optical signals of two time slots immediately after the even time slot and the odd time slot are perpendicular to each other.

In a fourth aspect, there is provided a demodulation and decoding apparatus having a function of realizing the behavior of the demodulation and decoding method in the second aspect described above. The demodulation and decoding device comprises one or more modules, and the one or more modules are used for realizing the demodulation and decoding method provided by the second aspect.

That is, the present application provides a demodulation decoding apparatus applied to a receiver, the apparatus including:

the receiving module is used for receiving the double-polarized light signal, the double-polarized light signal is determined according to a target coding mode and a modulation mapping rule, the target coding mode is determined according to a code space, and the code space is determined according to a Stokes constraint condition, a code distance constraint condition and the modulation mapping rule;

the processing module is used for processing the double-polarized light signal to obtain an X polarization symbol stream and a Y polarization symbol stream;

and the demodulation decoding module is used for demodulating and decoding the X polarization symbol stream and the Y polarization symbol stream according to a target demodulation decoding mode to obtain a first bit stream, and the target demodulation decoding mode is determined according to a target coding mode and a modulation mapping rule.

Optionally, the target demodulation and decoding manner includes a target demodulation manner and a target decoding manner, the target demodulation manner is determined according to the modulation and mapping rule, and the target decoding manner is determined according to the target encoding manner;

the demodulation decoding module comprises:

the demodulation module is used for demodulating the X polarization symbol stream and the Y polarization symbol stream according to a target demodulation mode to obtain a second bit stream;

and the decoding module is used for decoding the second bit stream according to the target decoding mode to obtain the first bit stream.

Optionally, the decoding module is specifically configured to:

and when the continuous N bits in the second bit stream are obtained, decoding the continuous N bits once according to a target decoding mode to obtain an information sequence, wherein the information sequence comprises k bits, k and N are integers greater than 0, and k is smaller than N.

Optionally, the target demodulation and decoding manner is used to indicate a mapping relationship between a polarization symbol sequence and an information sequence, where the polarization symbol sequence refers to a symbol subsequence included in an X-polarization symbol stream and a Y-polarization symbol stream, and the information sequence refers to a bit subsequence included in the first bit stream;

the demodulation decoding module is specifically configured to perform demodulation decoding on the X-polarization symbol stream and the Y-polarization symbol stream according to the mapping relationship to obtain a first bit stream.

In a fifth aspect, a communication device is provided, which includes a processor and a memory, where the memory is used to store a program for executing the coding modulation method provided by the first aspect and/or a program for executing the demodulation decoding method provided by the second aspect, and to store data for implementing the coding modulation method provided by the first aspect and/or the data for implementing the demodulation decoding method provided by the second aspect. The processor is configured to execute programs stored in the memory. The operating means of the memory device may further comprise a communication bus for establishing a connection between the processor and the memory.

In a sixth aspect, a computer-readable storage medium is provided, which stores instructions that, when executed on a computer, cause the computer to perform the code modulation method of the first aspect and/or the demodulation and decoding method of the second aspect.

In a seventh aspect, there is provided a computer program product containing instructions which, when run on a computer, cause the computer to perform the method for encoding and modulating according to the first aspect, and/or the method for demodulating and decoding according to the second aspect.

The technical effects obtained by the third, fourth, fifth, sixth and seventh aspects are similar to the technical effects obtained by the corresponding technical means in the first or second aspect, and are not described herein again.

The technical scheme that this application provided can bring following beneficial effect at least:

in the application, the transmitter may encode the first bit stream according to a target encoding mode to obtain a second bit stream, and then adjust the second bit stream according to a modulation mapping rule to obtain an X polarization symbol stream and a Y polarization symbol stream, and further perform electro-optical modulation on the X polarization symbol stream and the Y polarization symbol stream to generate a dual-polarization signal, and send the dual-polarization signal to the receiver. The target coding mode is determined according to a code space, and the code space is determined according to a Stokes constraint condition, a code distance constraint condition and a modulation mapping rule, so that the code space can meet the Stokes constraint condition to resist a nonlinear effect, and can also meet the code distance constraint condition to improve the fault-tolerant capability of the system, so that the overall transmission performance of the system is better, and a receiver can receive a higher-quality dual-polarized signal.

Drawings

Fig. 1 is a system architecture diagram according to a coding modulation and demodulation decoding method provided in an embodiment of the present application;

fig. 2 is a schematic structural diagram of a communication device according to an embodiment of the present application;

fig. 3 is a flowchart of a code modulation method according to an embodiment of the present application;

FIG. 4 is a diagram illustrating Stokes constraints provided by an embodiment of the present application;

FIG. 5 is a schematic diagram of another Stokes constraint provided by an embodiment of the present application;

fig. 6 is a flowchart of another modulation and coding method provided in an embodiment of the present application;

fig. 7 is a flowchart of a demodulation and decoding method according to an embodiment of the present application;

fig. 8 is a flowchart of another demodulation and decoding method provided in the embodiment of the present application;

fig. 9 is a schematic structural diagram of a coded modulation apparatus according to an embodiment of the present application;

fig. 10 is a schematic structural diagram of a demodulation and decoding apparatus according to an embodiment of the present application.

Detailed Description

To make the objects, technical solutions and advantages of the present application more clear, embodiments of the present application will be described in further detail below with reference to the accompanying drawings.

Fig. 1 is a system architecture diagram according to a coding modulation and demodulation decoding method provided in an embodiment of the present application. Referring to fig. 1, the system architecture includes a transmitter 101 and a receiver 102, and the transmitter 101 and the receiver 102 may be connected for communication by an optical fiber link.

The transmitter 101 is configured to perform coded modulation on the first bit stream according to the coded modulation method provided in the embodiment of the present application to obtain an X-polarization symbol stream and a Y-polarization symbol stream, and power up the X-polarization symbol stream and the Y-polarization symbol stream to perform electro-optical modulation, generate a dual-polarization signal, and send the dual-polarization signal to the receiver 102 through an optical fiber link.

The receiver 102 is configured to receive a dual-polarization signal transmitted by the transmitter 101, process the dual-polarization signal to obtain an X-polarization symbol stream and a Y-polarization symbol stream, and demodulate and decode the X-polarization symbol stream and the Y-polarization symbol stream according to a demodulation and decoding method provided in this embodiment of the present application to obtain a first bit stream.

Referring to fig. 2, fig. 2 is a schematic structural diagram of a communication device according to an embodiment of the present application. Optionally, the communication device is a transmitter or receiver as shown in fig. 1, the communication device comprising one or more processors 201, a communication bus 202, a memory 203, one or more communication interfaces 204, and a light source 205.

The processor 201 is a general-purpose Central Processing Unit (CPU), a Network Processor (NP), a microprocessor, or one or more integrated circuits such as an application-specific integrated circuit (ASIC), a Programmable Logic Device (PLD), or a combination thereof for implementing the disclosed aspects. Optionally, the PLD is a Complex Programmable Logic Device (CPLD), a field-programmable gate array (FPGA), a General Array Logic (GAL), or any combination thereof.

A communication bus 202 is used to transfer information between the above components. Optionally, the communication bus 202 is divided into an address bus, a data bus, a control bus, and the like. For ease of illustration, only one thick line is shown, but this does not mean that there is only one bus or one type of bus.

Alternatively, the memory 203 is, but is not limited to, a read-only memory (ROM), a Random Access Memory (RAM), an electrically erasable programmable read-only memory (EEPROM), an optical disk (including a compact disk-read-only memory (CD-ROM), a compact disk, a laser disk, a digital versatile disk, a Blu-ray disk, etc.), a magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. The memory 203 is separate and connected to the processor 201 via the communication bus 202, or the memory 203 is integrated with the processor 201.

The communication interface 204 uses any transceiver or the like for communicating with other devices or communication networks. The communication interface 204 includes a wired communication interface and optionally a wireless communication interface. Among them, a wired communication interface such as an ethernet interface or the like. Optionally, the ethernet interface is an optical interface, an electrical interface, or a combination thereof. The wireless communication interface is a Wireless Local Area Network (WLAN) interface, a cellular network communication interface, or a combination thereof.

Optionally, in some embodiments, the communication device includes a plurality of processors, each of which is a single-core processor, or a multi-core processor. A processor herein optionally refers to one or more devices, circuits, and/or processing cores for processing data (e.g., computer program instructions).

In a specific implementation, the communication device further includes an output device 206 and an input device 207, as an embodiment. The output device 206 is in communication with the processor 201 and is capable of displaying information in a variety of ways. For example, the output device 206 is a Liquid Crystal Display (LCD), a Light Emitting Diode (LED) display device, a Cathode Ray Tube (CRT) display device, a projector (projector), or the like. The input device 207 is in communication with the processor 201 and is capable of receiving user input in a variety of ways. For example, the input device 207 is a mouse, a keyboard, a touch screen device, a sensing device, or the like.

In some embodiments, the memory 203 is used to store program code 210 for performing aspects of the present application, and the processor 201 is capable of executing the program code 210 stored in the memory 203. The program code includes one or more software modules, and the communication device can implement the encoding and modulation method provided in the embodiments of fig. 3 and fig. 6 below, or the demodulation and decoding method provided in the embodiments of fig. 7 and fig. 8, by using the processor 201 and the program code 210 in the memory 203.

Fig. 3 is a flowchart of a code modulation method provided in an embodiment of the present application, where the method is applied to a transmitter. Referring to fig. 3, the method includes the following steps.

Step 301: the transmitter acquires a first bit stream.

In an embodiment of the present application, a transmitter may receive a source bit stream as a first bit stream.

Optionally, after receiving the source bit stream, the transmitter may further perform Forward Error Correction (FEC) coding on the source bit stream to obtain the first bit stream.

The embodiment of the present application does not limit the forward error correction coding method.

Step 302: and the transmitter codes the first bit stream according to a target coding mode to obtain a second bit stream, wherein the target coding mode is determined according to a code space, and the code space is determined according to a Stokes constraint condition, a code distance constraint condition and a modulation mapping rule.

In this embodiment, a target coding scheme may be configured in the transmitter, and the transmitter may code the first bit stream according to the target coding scheme to obtain the second bit stream, where the target coding scheme is determined according to a code space, and the code space is determined according to a stokes constraint condition, a code distance constraint condition, and a modulation mapping rule. That is, in order to resist the nonlinear effect in the optical fiber link, the code space in the embodiment of the present application satisfies the stokes constraint condition, and in order to further improve the fault tolerance capability of the system, the code space also satisfies the code distance constraint condition, and the design of the code space may also consider the modulation mapping rule.

In this embodiment of the present application, a manner in which the transmitter encodes the first bit stream according to the target encoding manner may be that, each time the transmitter acquires k consecutive bits in the first bit stream, the k consecutive bits are encoded once according to the target encoding manner to obtain one codeword, where one codeword includes N bits. Wherein k and N are integers greater than 0, and k is less than N.

Optionally, in this embodiment of the present application, one code space may correspond to one or more coding modes, and the target coding mode is one of the one or more coding modes. That is, any one of the one or more encoding schemes may uniquely map any one of the k-bit sequences to a codeword in the code space.

For example, one of the encoding manners may be a mapping table, where the mapping table exhales the mapping relationship between each k-bit sequence and the codeword, and the transmitter may encode the first bit stream according to the mapping table to obtain the second bit stream. For another example, another encoding method may use a form of a coding formula to identify a relationship between each bit in the codeword and each bit in the k-bit sequence, and the transmitter may encode the first bit stream according to the coding formula to obtain the second bit stream.

Optionally, in this embodiment of the present application, one or more code spaces may be further configured in the transmitter, a stokes constraint condition, a code distance constraint condition, or a modulation mapping rule that are satisfied by each code space may be the same or different, lengths of codewords of each code space may be the same or different, and the transmitter may determine one code space according to a communication requirement.

Step 303: the transmitter modulates the second bit stream according to the modulation mapping rule to obtain an X-polarization symbol stream and a Y-polarization symbol stream.

In this embodiment, after obtaining the second bit stream, the transmitter may modulate the second bit stream according to a modulation mapping rule to obtain an X-polarization symbol stream and a Y-polarization symbol stream.

Alternatively, the modulation mapping rule may be determined based on QPSK, such that N may be an integer multiple of 8, and the resulting X-polarization symbol stream and Y-polarization symbol stream each include a plurality of consecutive N/4 slots.

It should be noted that one symbol of QPSK may be represented by two bits, and at least two consecutive slots included in the X-polarization symbol stream and the Y-polarization symbol stream obtained after modulation need to satisfy the stokes constraint condition, so that two consecutive slots included in the X-polarization symbol stream and the Y-polarization symbol stream may be represented by 4 symbols, so that two consecutive slots included in the X-polarization symbol stream and the Y-polarization symbol stream correspond to 8 bits, and therefore N may be an integer multiple of 8. In other embodiments, the modulation mapping rule may be determined based on any other modulation method, so that the value of N may need to be changed accordingly.

Alternatively, the modulation mapping rule determined based on QPSK may be one or more, and the transmitter may select one modulation mapping rule in advance.

Illustratively, table 1 is a modulation mapping rule provided in an embodiment of the present application. Referring to table 1, the modulation mapping rule is determined based on QPSK and is a polarization modulation scheme. Wherein the code word has a length of N, one code word comprises N/4 bit sequences, c ₁ c ₂ c ₃ c ₄ C may be one of N/4 bit sequences included for any one codeword ₁ c ₂ These two bits are mapped according to Table 1 to obtain one symbol in the X polarization symbol stream, c ₃ c ₄ These two bits are mapped according to table 1 to obtain one symbol in the Y-polarized symbol stream. In this way, the X-polarization symbol stream and the Y-polarization symbol stream can be obtained by sequentially modulating and mapping the codewords in the second bit stream according to table 1.

TABLE 1

Step 304: the transmitter electro-optically modulates the X-polarization symbol stream and the Y-polarization symbol stream to generate a dual-polarization signal, and transmits the dual-polarization signal.

In this embodiment, after obtaining the X-polarization symbol stream and the Y-polarization symbol stream, the transmitter may add light to the X-polarization symbol stream and the Y-polarization symbol stream to perform electro-optical modulation, so as to generate a dual-polarization signal, that is, convert a digital signal into an analog signal. The receiver can then send the dual-polarization signal to the receiver through an optical fiber link, so that the dual-polarization field obtained after electro-optical modulation can carry light source information to the receiver.

For example, the transmitter may convert the X-polarization symbol stream and the Y-polarization symbol stream into analog signals through digital-to-analog conversion (DAC), where each analog signal includes an I-path signal and a Q-path signal, and the analog signals may further undergo radio frequency amplification, and drive the two amplified analog signals through a double-polarization electro-optical modulator to obtain double-polarization signals, and send the double-polarization signals to the receiver through an optical fiber link. The double-polarization electro-optical modulator can use a single-frequency continuous light source as an input.

As can be seen from the foregoing, the target coding mode is determined according to a code space, and the code space is determined according to a stokes constraint condition, a code distance constraint condition and a modulation mapping rule, and the code space provided in the embodiment of the present application is described in detail below.

In the embodiment of the present application, in the case that the modulation mapping rule is determined based on QPSK, the aforementioned k may be equal to 9,N may be equal to 16, and the code distance constraint may refer to that the minimum code distance of the code space is 4. Therefore, the nonlinear effect can be resisted, and the fault tolerance of the system is improved, so that the overall transmission performance of the system is improved.

In the embodiment of the present application, the stokes vector may be calculated according to formula (1).

Wherein E is _x And E _y The amplitudes of the X-polarized light field and the Y-polarized light field of one slot are represented, re (-) and Im (-) represent the real part and the imaginary part, respectively.

Optionally, two stokes constraints are provided in the embodiments of the present application, and the first stokes constraint may refer to that the sum of the stokes vectors of the optical signals of two immediately adjacent time slots in N/4 consecutive time slots is a zero vector.

Referring to fig. 4, assuming that k is equal to 9,N is equal to 16, the x-polarization symbol stream and the Y-polarization symbol stream include a plurality of consecutive 4 slots, the 4 slots are T1, T2, T3, and T4 in sequence, and the stokes vectors of the optical signals corresponding to the slots T1, T2, T3, and T4 are S1, S2, S3, and S4, respectively, the stokes constraint condition may be:

optionally, in this embodiment of the present application, after determining k, N, and code distance constraint conditions, code words meeting the stokes condition and the code distance constraint condition may be found from all N bit sequences with a length of N according to a modulation mapping rule, and 2 k-th power code words are randomly selected from all code words meeting the conditions to form one code space, so that one or more code spaces may be obtained. That is, the code space meeting the condition can be found by adopting a violent enumeration mode.

Different concepts and tools can be used for describing the same code space. In order to quickly determine the code space satisfying the condition, in the embodiment of the present application, the code space may be determined in a manner described by a coset leader.

Alternatively, assuming that the code distance constraint condition means that the minimum code distance of the code space is 4, the stokes constraint condition is the constraint condition introduced in fig. 4, and the modulation mapping rule is the rule shown in table 1, the code space may be determined according to the first formula, which is formula (2).

Wherein, in the first formula, W is a code space, v _i Refers to a coset leader of length N for describing code space, N refers to v _i K is the nuclear space, and

v _i ∈V，V＝V ^(p) ∪V ^(q) ；

After the calculation, four code spaces, namely a code space I, a code space II, a code space III and a code space IV can be determined and obtained, wherein the code space I is according to the V ⁽¹⁾ And V ⁽²⁾ Determined, code space II being according to V ⁽³⁾ And V ⁽⁴⁾ Determined, code space three is according to V above ⁽¹⁾ And V ⁽⁴⁾ Determined that the code space four is according to V ⁽²⁾ And V ⁽³⁾ And (4) determining.

Referring to table 2, an embodiment of the present application provides a coding method determined according to the code space one, the code space two, the code space three, and the code space four. Wherein, b ₁ b ₂ ...b ₉ For 9 consecutive bits (information bits) in the first bit stream, c ₁ c ₂ ...c ₁₆ For a code word in the code space, as can be seen from Table 2, c can be selected ₁ 、c ₂ 、c ₃ 、c ₄ 、c ₅ 、c ₆ 、c ₉ 、c ₁₀ 、c ₁₃ Equal to the information bits.

TABLE 2

In the embodiment of the present application, the same code space may have more than one coding mode, and the information bits may be selected differently in different coding modes. Referring to table 3, another encoding method determined according to the first code space is provided in the embodiments of the present application. As can be seen from Table 3, c can be selected ₁ 、c ₂ 、c ₃ 、c ₄ 、c ₅ 、c ₆ 、c ₉ 、c ₁₃ 、c ₁₄ Equal to the information bits.

TABLE 3

Alternatively, the second stokes constraint condition may mean that the sum of stokes vectors of optical signals of two slots immediately before and after the odd-numbered slot in the N/4 consecutive slots is zero vector, and the stokes vectors of optical signals of two slots immediately before and after the even-numbered slot are perpendicular to each other.

Referring to fig. 5, assuming that k is equal to 9,N is equal to 16, the x-polarization symbol stream and the Y-polarization symbol stream include a plurality of consecutive 4 slots, the 4 slots are T1, T2, T3, and T4 in sequence, and the stokes vectors of the optical signals corresponding to the slots T1, T2, T3, and T4 are S1, S2, S3, and S4, respectively, the stokes constraint condition may be:

taking the stokes condition shown in fig. 5 as an example, in the embodiment of the present application, a code space meeting the condition may also be found in a manner of brute force enumeration. Or, in order to quickly determine a code space satisfying the condition, the code space may be determined in a manner described by a coset leader.

Alternatively, assuming that the code distance constraint condition means that the minimum code distance of the code space is 4, the stokes constraint condition is the constraint condition introduced in fig. 5, and the modulation mapping rule is the rule shown in table 1, the code space may be according to the first formula

And (4) determining. Wherein the content of the first and second substances,

v _i ∈V，V＝V ^(p) ∪V ^(q) ；

After the calculation, four code spaces can be determined and obtained, namely a code space five, a code space six, a code space seven and a code space eight, wherein the code space five is according to the V ⁽⁵⁾ And V ⁽⁶⁾ Determining that code space six is according to V ⁽⁷⁾ And V ⁽⁸⁾ Defining a code space seven according to V ⁽⁵⁾ And V ⁽⁸⁾ Determined that code space eight is according to V above ⁽⁶⁾ And V ⁽⁷⁾ And (4) determining.

Referring to table 4, an encoding method determined according to the code space five, the code space six, the code space seven, and the code space eight is provided in the embodiment of the present application.

TABLE 4

Next, a coded modulation method provided by the embodiment of the present application is described with reference to fig. 6. Referring to fig. 6, a transmitter may receive a source bit stream a and perform error correction coding on the source bit stream a according to an FEC encoder to obtain a first bit stream b. Then, the nonlinear cancellation module of the transmitter may encode the first bit stream b according to the target coding method to obtain a second bit stream c. The transmitter may then modulate the second bit stream according to QPSK modulation mapping rules to obtain an X-polarization symbol stream and a Y-polarization symbol stream. Then, the transmitter may employ a single-frequency continuous light source to perform electro-optical modulation on the X-polarization symbol stream and the Y-polarization symbol stream to obtain a dual-polarization signal, and send the dual-polarization signal to the receiver through the optical fiber link.

It should be noted that, the nonlinear cancellation module in fig. 6 enables the finally obtained dual-polarized light signal after code modulation to satisfy the stokes vector constraint condition by a target coding manner, and can resist the nonlinear effect, and the code rate is k/N, so that the coding gain is satisfied, and the performance of the system can be further improved. The selection of the code space in the embodiment of the application determines the coding gain of the system, thereby improving the overall transmission performance of the system. In addition, if the modulation mapping rule changes, the coding process of the nonlinear cancellation module also changes correspondingly, for example, operations such as interleaving and negation are added, so as to satisfy that the final optical signal after modulation satisfies the constraint condition, that is, the design of the nonlinear cancellation module and the modulation mapping rule is comprehensively considered, so that the final optical signal can satisfy the constraint condition.

In this embodiment of the present application, the transmitter may encode the first bit stream according to a target encoding manner to obtain a second bit stream, and then adjust the second bit stream according to a modulation mapping rule to obtain an X polarization symbol stream and a Y polarization symbol stream, and further perform electro-optical modulation on the X polarization symbol stream and the Y polarization symbol stream to generate a dual-polarization signal, and send the dual-polarization signal to the receiver. The target coding mode is determined according to a code space, and the code space is determined according to a Stokes constraint condition, a code distance constraint condition and a modulation mapping rule, so that the code space can meet the Stokes constraint condition to resist a nonlinear effect, and can also meet the code distance constraint condition to improve the fault-tolerant capability of the system, so that the overall transmission performance of the system is better.

Fig. 7 is a flowchart of a demodulation and decoding method provided in an embodiment of the present application, and the method is applied to a receiver. Referring to fig. 7, the method includes the following steps.

Step 701: the receiver receives a double-polarized light signal, wherein the double-polarized light signal is determined according to a target coding mode and a modulation mapping rule, the target coding mode is determined according to a code space, and the code space is determined according to a Stokes constraint condition, a code distance constraint condition and the modulation mapping rule.

In this embodiment, the receiver may receive a dual-polarized light signal sent by the transmitter in this embodiment, where the dual-polarized light signal is determined according to a target coding scheme and a modulation mapping rule, the target coding scheme is determined according to a code space, and the code space is determined according to a stokes constraint condition, a code distance constraint condition, and the modulation mapping rule.

It should be noted that the target coding mode, the code space, and the modulation mapping rule are the same as those described in the foregoing embodiments, that is, the code space satisfies the stokes constraint condition to resist the nonlinear effect, and satisfies the code distance constraint condition to provide the fault-tolerant capability of the system, so as to further improve the overall transmission performance of the system, and ensure that the quality of the double-polarized light signal received by the receiver is higher. The method for determining the target coding mode and the code space may refer to the related descriptions in the foregoing embodiments, and will not be described herein again.

Step 702: and the receiver processes the double polarization signals to obtain an X polarization symbol stream and a Y polarization symbol stream.

In this embodiment, the receiver may use a single-frequency continuous light source to mix with the dual-polarized light signal, convert the mixed dual-polarized light signal into an electrical digital signal through the analog-to-digital converter and the sampler, and then send the electrical digital signal to the DSP module for digital signal processing, such as equalization and filtering, to obtain the X-polarized symbol stream and the Y-polarized symbol stream.

It should be noted that the receiver processes the dual polarized signals to minimize the error between the recovered X-polarized symbol stream and the recovered Y-polarized symbol stream and the X-polarized symbol stream and the recovered Y-polarized symbol stream generated in the transmitter.

Step 703: and the receiver demodulates and decodes the X polarization symbol stream and the Y polarization symbol stream according to a target demodulation decoding mode to obtain a first bit stream, wherein the target demodulation decoding mode is determined according to the target coding mode and the modulation mapping rule.

In this embodiment, after recovering the X-polarization symbol stream and the Y-polarization symbol stream, the receiver may demodulate and decode the X-polarization symbol stream and the Y-polarization symbol stream according to a target demodulation and decoding manner, where the target demodulation and decoding manner is determined according to the target encoding manner and the modulation and mapping rule in the foregoing embodiments.

Optionally, in this embodiment of the present application, the target demodulation and decoding manner may include a target demodulation manner and a target decoding manner, where the target demodulation manner is determined according to the modulation mapping rule, and the target decoding manner is determined according to the target encoding manner. The receiver may demodulate the restored X-polarization symbol stream and Y-polarization symbol stream according to a target demodulation manner to obtain a second bit stream, and then decode the second bit stream according to a target decoding manner to obtain a first bit stream. That is, the receiver may perform the demodulation operation and then the decoding operation to recover the first bit stream.

The receiver decodes the second bit stream according to the target decoding manner, where each time the receiver obtains N consecutive bits in the second bit stream, the receiver decodes the N consecutive bits once according to the target decoding manner to obtain an information sequence, where the information sequence includes k bits, where k and N are integers greater than 0, and k is smaller than N.

Optionally, in this embodiment of the present application, the target demodulation and decoding manner may also be used to indicate a mapping relationship between a polarization symbol sequence and an information sequence, where the polarization symbol sequence may refer to a symbol subsequence included in the X-polarization symbol stream and the Y-polarization symbol stream, and the information sequence may refer to a bit subsequence included in the first bit stream. In this way, the receiver can demodulate and decode the X-polarization symbol stream and the Y-polarization symbol stream according to the mapping relationship to obtain the first bit stream. That is, the receiver may perform a mapping operation once to recover the first bit stream.

It should be noted that the receiver may use the nearest likelihood criterion for estimation during the demodulation and decoding process, so as to minimize the error between the recovered first bit stream and the first bit stream generated in the transmitter as much as possible.

Optionally, in the case that the source bit stream is FEC-encoded in the transmitter, after obtaining the first bit stream, the receiver may further perform FEC decoding on the first bit stream to recover the source bit stream, and minimize an error between the recovered source bit stream and the source bit stream obtained by the transmitter.

The demodulation and decoding method provided by the embodiment of the present application is described again with reference to fig. 8. Referring to fig. 8, the receiver may use a single-frequency continuous light source to mix with the dual-polarized light signal, and convert the mixed dual-polarized light signal into an electrical digital signal through an analog-to-digital converter. The receiver may then send the electrical digital signal to a DSP module for digital signal processing to obtain an X-polarization symbol stream and a Y-polarization symbol stream. Then, the receiver may demodulate and decode the obtained X-polarization symbol stream and Y-polarization symbol stream according to a target demodulation and decoding manner in the high-dimensional signal demodulation module to obtain a first bit stream b. Finally, the receiver can perform FEC decoding on the first bit stream b to recover the source bit stream a.

In summary, in the embodiment of the present application, the receiver may receive a dual-polarized light signal transmitted by the transmitter, where the dual-polarized light signal is determined according to a target coding manner and a modulation mapping rule, the target coding manner is determined according to a code space, and the code space is determined according to a stokes constraint condition, a code distance constraint condition, and a modulation mapping rule, so that the code space may satisfy the stokes constraint condition to resist a nonlinear effect, and the code space may also satisfy the code distance constraint condition, thereby improving the fault tolerance of the system. Therefore, the overall transmission performance of the system is better, the receiver can receive the double-polarization signal with higher quality, and after demodulating and decoding the received double-polarization signal according to the target demodulation and decoding mode, the error between the obtained first bit stream and the first bit stream in the transmitter is smaller.

Fig. 9 is a schematic structural diagram of a code modulation apparatus provided in an embodiment of the present application, where the code modulation apparatus 900 may be implemented by software, hardware, or a combination of the two to be part or all of a communication device, which may be the communication device shown in fig. 2. Referring to fig. 9, the apparatus 900 includes: an obtaining module 901, an encoding module 902, a modulating module 903 and a sending module 904.

An obtaining module 901, configured to obtain a first bit stream;

a coding module 902, configured to code the first bit stream according to a target coding mode to obtain a second bit stream, where the target coding mode is determined according to a code space, and the code space is determined according to a stokes constraint condition, a code distance constraint condition, and a modulation mapping rule;

a modulation module 903, configured to modulate the second bit stream according to a modulation mapping rule to obtain an X polarization symbol stream and a Y polarization symbol stream;

and a sending module 904, configured to perform electro-optical modulation on the X-polarization symbol stream and the Y-polarization symbol stream, generate a dual-polarization signal, and send the dual-polarization signal.

Optionally, the encoding module 902 is specifically configured to:

Optionally, the stokes constraint condition means that the sum of stokes vectors of optical signals of two time slots immediately before and after an odd time slot in consecutive N/4 time slots is zero vector, and the stokes vectors of optical signals of two time slots immediately before and after the even time slot are perpendicular to each other.

In this embodiment of the application, the transmitter may encode the first bit stream according to a target encoding manner to obtain a second bit stream, and then adjust the second bit stream according to a modulation mapping rule to obtain an X polarization symbol stream and a Y polarization symbol stream, and further perform electro-optical modulation on the X polarization symbol stream and the Y polarization symbol stream to generate a dual-polarization signal, and send the dual-polarization signal to the receiver. The target coding mode is determined according to a code space, and the code space is determined according to a Stokes constraint condition, a code distance constraint condition and a modulation mapping rule, so that the code space can meet the Stokes constraint condition to resist a nonlinear effect, and can also meet the code distance constraint condition to improve the fault-tolerant capability of the system, so that the overall transmission performance of the system is better.

It should be noted that: in the coded modulation apparatus provided in the above embodiment, only the division of the functional modules is illustrated when coded modulation is performed, and in practical applications, the functions may be distributed by different functional modules according to needs, that is, the internal structure of the apparatus is divided into different functional modules to complete all or part of the functions described above. In addition, the embodiments of the code modulation apparatus and the code modulation method provided in the above embodiments belong to the same concept, and specific implementation processes thereof are described in the embodiments of the methods for details, which are not described herein again.

Fig. 10 is a schematic structural diagram of a demodulation and decoding apparatus provided in an embodiment of the present application, where the demodulation and decoding apparatus 1000 may be implemented by software, hardware, or a combination of the two to be part or all of a communication device, which may be the communication device shown in fig. 2. Referring to fig. 10, the apparatus 1000 includes: a receiving module 1001, a processing module 1002 and a demodulation decoding module 1003.

A receiving module 1001, configured to receive a dual-polarized light signal, where the dual-polarized light signal is determined according to a target coding scheme and a modulation mapping rule, the target coding scheme is determined according to a code space, and the code space is determined according to a stokes constraint condition, a code distance constraint condition, and a modulation mapping rule;

a processing module 1002, configured to process the dual polarization signal to obtain an X polarization symbol stream and a Y polarization symbol stream;

a demodulation decoding module 1003, configured to perform demodulation decoding on the X-polarization symbol stream and the Y-polarization symbol stream according to a target demodulation decoding manner, so as to obtain a first bit stream, where the target demodulation decoding manner is determined according to a target encoding manner and a modulation mapping rule.

the demodulation decoding module 1003 includes:

Optionally, the decoding module is specifically configured to:

the demodulation decoding module 1003 is specifically configured to demodulate and decode the X polarization symbol stream and the Y polarization symbol stream according to the mapping relationship, so as to obtain a first bit stream.

In the embodiment of the application, a receiver can receive a double-polarized light signal, the double-polarized light signal is determined according to a target coding mode and a modulation mapping rule, the target coding mode is determined according to a code space, and the code space is determined according to a stokes constraint condition, a code distance constraint condition and a modulation mapping rule, so that the code space can meet the stokes constraint condition to resist a nonlinear effect, and can also meet the code distance constraint condition to improve the fault tolerance of a system. Therefore, the overall transmission performance of the system is better, the receiver can receive the double-polarization signal with higher quality, and after demodulating and decoding the received double-polarization signal according to the target demodulation and decoding mode, the error between the obtained first bit stream and the first bit stream in the transmitter is smaller.

It should be noted that: in the demodulation and decoding device provided in the foregoing embodiment, only the division of the above functional modules is used for illustration when performing demodulation and decoding, and in practical applications, the above functions may be distributed by different functional modules as needed, that is, the internal structure of the device is divided into different functional modules to complete all or part of the above described functions. In addition, the embodiments of the demodulation and decoding apparatus and the demodulation and decoding method provided in the above embodiments belong to the same concept, and specific implementation processes thereof are detailed in the embodiments of the methods and are not described herein again.

In the above embodiments, it may be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented in software, may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When loaded and executed on a computer, cause the processes or functions described in accordance with the embodiments of the application to occur, in whole or in part. The computer may be a general purpose computer, a special purpose computer, a network of computers, or other programmable device. The computer instructions may be stored on a computer readable storage medium or transmitted from one computer readable storage medium to another, for example, from one website, computer, server, or data center to another website, computer, server, or data center via wire (e.g., coaxial cable, fiber optic, digital Subscriber Line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device, such as a server, a data center, etc., that includes one or more of the available media. The usable medium may be a magnetic medium (e.g., a floppy disk, a hard disk, a magnetic tape), an optical medium (e.g., a Digital Versatile Disk (DVD)), or a semiconductor medium (e.g., a Solid State Disk (SSD)), among others. It is noted that the computer-readable storage medium referred to herein may be a non-volatile storage medium, in other words, a non-transitory storage medium.

The above-mentioned embodiments are provided not to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method of coded modulation, the method comprising:

a transmitter acquires a first bit stream;

the transmitter encodes the first bit stream according to a target encoding mode to obtain a second bit stream, wherein the target encoding mode is determined according to a code space, the code space is determined according to a Stokes constraint condition, a code distance constraint condition and a modulation mapping rule, any k bit sequence in the first bit stream is uniquely mapped to be a code word in the code space, the code word comprises N bits, both k and N are integers greater than 0, and k is smaller than N;

the transmitter modulates the second bit stream according to the modulation mapping rule to obtain an X polarization symbol stream and a Y polarization symbol stream;

the transmitter performs electro-optical modulation on the X-polarization symbol stream and the Y-polarization symbol stream to generate a double-polarization signal, and transmits the double-polarization signal, wherein the X-polarization symbol stream and the Y-polarization symbol stream both comprise a plurality of continuous N/4 time slots, and N is an integral multiple of 8;

the Stokes constraint condition means that the sum of Stokes vectors of optical signals of two adjacent time slots in the continuous N/4 time slots is a zero vector; or the stokes constraint condition means that the sum of stokes vectors of optical signals of two adjacent time slots before and after an odd time slot in the continuous N/4 time slots is zero vector, and the stokes vectors of optical signals of two adjacent time slots before and after the even time slot are mutually vertical; the code spaces determined by different stokes constraint conditions are different, and the corresponding coding mode of each code space is different.

2. The method of claim 1, wherein the transmitter encodes the first bit stream according to a target coding scheme, comprising:

and the transmitter encodes the continuous k bits once according to the target encoding mode to obtain a code word every time the transmitter acquires the continuous k bits in the first bit stream.

3. The method of claim 1, wherein the code space corresponds to one or more encoding modes, and the target encoding mode is one of the one or more encoding modes.

4. A method according to any of claims 1-3, wherein the modulation mapping rule is determined based on quadrature phase shift keying, QPSK.

5. The method of claim 4, wherein k is equal to 9, wherein N is equal to 16, and wherein the code distance constraint indicates that the minimum code distance of the code space is 4.

6. The method of claim 1, wherein if the stokes constraint condition is that the sum of stokes vectors of optical signals of two adjacent time slots in the consecutive N/4 time slots is a zero vector; the code space is determined according to a first formula;

the first formula is:

wherein, in the first formula, W refers to the code space, v _i Refers to a coset leader of length N for describing the code space, where N refers to the v _i Said K is the nuclear space, and said

Wherein u is _j Is a row vector of length equal to 6, said m referring to said u _j M equals 2 to the power of 6, said

V is _i E.v, said V = V ^(p) ∪V ^(q) ；

The p =1,q =2, or p =3,q =4, or p =1,q =4, or p =2,q =3.

7. The method of claim 1, wherein if the stokes constraint condition means that the sum of stokes vectors of optical signals of two time slots immediately after an odd time slot and an even time slot in the consecutive N/4 time slots is zero vector, and the stokes vectors of optical signals of two time slots immediately after an even time slot and an odd time slot are perpendicular to each other, the code space is determined according to a first formula;

the first formula is:

wherein, in the first formula, the W refers to the code space, the v _i Refers to a coset leader of length N for describing the code space, where N refers to the v _i Said K is the nuclear space, and said

V is _i E.v, said V = V ^(p) ∪V ^(q) ；

The p =5,q =6, or p =7,q =8, or p =5,q =8, or p =6,q =7.

8. A demodulation and decoding method, the method comprising:

the method comprises the steps that a receiver receives double-polarized light signals, wherein the double-polarized light signals are obtained by determining according to a target coding mode and a modulation mapping rule, the target coding mode is determined according to a code space, and the code space is determined according to a Stokes constraint condition, a code distance constraint condition and the modulation mapping rule;

the receiver processes the double-polarized light signal to obtain an X polarization symbol stream and a Y polarization symbol stream;

the receiver demodulates and decodes the X polarization symbol stream and the Y polarization symbol stream according to a target demodulation decoding mode to obtain a first bit stream, wherein the target demodulation decoding mode is determined according to the target coding mode and the modulation mapping rule;

any k bit sequence in the first bit stream is uniquely mapped to a codeword in the code space, the codeword includes N bits, k and N are both integers greater than 0, and k is smaller than N; the N is an integral multiple of 8, and the X polarization symbol stream and the Y polarization symbol stream both comprise a plurality of continuous N/4 time slots;

the Stokes constraint condition means that the sum of Stokes vectors of optical signals of two adjacent time slots in the continuous N/4 time slots is a zero vector; or, the stokes constraint condition means that the sum of stokes vectors of optical signals of two adjacent time slots before and after an odd time slot in the consecutive N/4 time slots is a zero vector, and the stokes vectors of optical signals of two adjacent time slots before and after the even time slot are mutually perpendicular; the code spaces determined by different stokes constraint conditions are different, and the corresponding coding modes of each code space are different.

9. The method of claim 8, wherein the target demodulation decoding scheme comprises a target demodulation scheme and a target decoding scheme, the target demodulation scheme is determined according to the modulation mapping rule, and the target decoding scheme is determined according to the target coding scheme;

the receiver demodulates and decodes the X-polarization symbol stream and the Y-polarization symbol stream according to a target demodulation and decoding manner to obtain a first bit stream, including:

the receiver demodulates the X polarization symbol stream and the Y polarization symbol stream according to the target demodulation mode to obtain a second bit stream;

and the receiver decodes the second bit stream according to the target decoding mode to obtain the first bit stream.

10. The method of claim 9, wherein the receiver decoding the second bit stream according to the target decoding scheme comprises:

and the receiver decodes the continuous N bits once according to the target decoding mode to obtain an information sequence every time the receiver obtains the continuous N bits in the second bit stream, wherein the information sequence comprises k bits, k and N are integers greater than 0, and k is smaller than N.

11. The method according to claim 8, wherein the target demodulation decoding manner is used to indicate a mapping relationship between a polarization symbol sequence and an information sequence, the polarization symbol sequence refers to a symbol subsequence included in the X-polarization symbol stream and the Y-polarization symbol stream, and the information sequence refers to a bit subsequence included in the first bit stream;

and the receiver demodulates and decodes the X polarization symbol stream and the Y polarization symbol stream according to the mapping relation to obtain the first bit stream.

12. A coded modulation apparatus, for use in a transmitter, the apparatus comprising:

an obtaining module, configured to obtain a first bitstream;

a coding module, configured to code the first bit stream according to a target coding scheme to obtain a second bit stream, where the target coding scheme is determined according to a code space, the code space is determined according to a stokes constraint condition, a code distance constraint condition, and a modulation mapping rule, any k bit sequence in the first bit stream is uniquely mapped to a codeword in the code space, the codeword includes N bits, both k and N are integers greater than 0, and k is smaller than N;

a modulation module, configured to modulate the second bit stream according to the modulation mapping rule to obtain an X polarization symbol stream and a Y polarization symbol stream;

a sending module, configured to perform electro-optical modulation on the X-polarization symbol stream and the Y-polarization symbol stream to generate a dual-polarization signal, and send the dual-polarization signal, where the X-polarization symbol stream and the Y-polarization symbol stream both include multiple consecutive N/4 time slots, and N is an integer multiple of 8;

the Stokes constraint condition means that the sum of Stokes vectors of optical signals of two adjacent time slots in the continuous N/4 time slots is a zero vector; or, the stokes constraint condition means that the sum of stokes vectors of optical signals of two adjacent time slots before and after an odd time slot in the consecutive N/4 time slots is a zero vector, and the stokes vectors of optical signals of two adjacent time slots before and after the even time slot are mutually perpendicular; the code spaces determined by different stokes constraint conditions are different, and the corresponding coding mode of each code space is different.

13. The apparatus of claim 12, wherein the encoding module is specifically configured to:

and each time k continuous bits in the first bit stream are obtained, once coding is performed on the k continuous bits according to the target coding mode to obtain a code word, wherein the code word comprises N bits, k and N are both integers greater than 0, and k is smaller than N.

14. The apparatus of claim 12, wherein the code space corresponds to one or more encoding modes, and the target encoding mode is one of the one or more encoding modes.

15. The apparatus according to any of claims 12-14, wherein the modulation mapping rule is determined based on QPSK.

16. The apparatus of claim 15, wherein k is equal to 9, wherein N is equal to 16, and wherein the code distance constraint means that the minimum code distance of the code space is 4.

17. A demodulation decoding apparatus, applied to a receiver, the apparatus comprising:

the receiving module is used for receiving a double-polarized light signal, wherein the double-polarized light signal is determined according to a target coding mode and a modulation mapping rule, the target coding mode is determined according to a code space, and the code space is determined according to a Stokes constraint condition, a code distance constraint condition and the modulation mapping rule;

a demodulation decoding module, configured to perform demodulation decoding on the X-polarization symbol stream and the Y-polarization symbol stream according to a target demodulation decoding manner to obtain a first bit stream, where the target demodulation decoding manner is determined according to the target encoding manner and the modulation mapping rule;

any k bit sequence in the first bit stream is uniquely mapped to a code word in the code space, the code word comprises N bits, k and N are integers greater than 0, and k is smaller than N; the N is an integral multiple of 8, and the X polarization symbol stream and the Y polarization symbol stream both comprise a plurality of continuous N/4 time slots;

18. The apparatus of claim 17, wherein the target demodulation and decoding scheme comprises a target demodulation scheme and a target decoding scheme, the target demodulation scheme is determined according to the modulation mapping rule, and the target decoding scheme is determined according to the target coding scheme;

the demodulation decoding module comprises:

the demodulation module is used for demodulating the X polarization symbol stream and the Y polarization symbol stream according to the target demodulation mode to obtain a second bit stream;

19. The apparatus according to claim 18, wherein the decoding module is specifically configured to:

and decoding the continuous N bits once according to the target decoding mode every time the continuous N bits in the second bit stream are obtained to obtain an information sequence, wherein the information sequence comprises k bits, k and N are integers greater than 0, and k is smaller than N.

20. The apparatus according to claim 17, wherein the target demodulation decoding means is configured to indicate a mapping relationship between a polarization symbol sequence and an information sequence, the polarization symbol sequence refers to a symbol subsequence included in the X-polarization symbol stream and the Y-polarization symbol stream, and the information sequence refers to a bit subsequence included in the first bit stream;

the demodulation decoding module is specifically configured to perform demodulation decoding on the X-polarization symbol stream and the Y-polarization symbol stream according to the mapping relationship to obtain the first bit stream.

21. A computer-readable storage medium, characterized in that the storage medium has stored therein a computer program which, when being executed by a processor, carries out the steps of the method of any one of claims 1 to 7 or the steps of the method of any one of claims 8 to 11.