CN112532555B

CN112532555B - Constellation rotation encryption method based on codebook mapping and constellation expansion

Info

Publication number: CN112532555B
Application number: CN202110186891.4A
Authority: CN
Inventors: 王世练; 施育鑫; 鲁信金; 雷菁; 李为; 于龙; 李玉生
Original assignee: National University of Defense Technology
Current assignee: National University of Defense Technology
Priority date: 2021-02-18
Filing date: 2021-02-18
Publication date: 2021-04-23
Anticipated expiration: 2041-02-18
Also published as: CN112532555A

Abstract

The application relates to a constellation rotation encryption method based on codebook mapping and constellation expansion, which comprises the following steps: performing first phase shift keying modulation on the coded data at a data sending end, and mapping each constellation point in the first modulated data to a plurality of constellation points according to a codebook mapping function to complete second phase shift keying modulation; and demodulating the secondary modulation data at the data receiving end, carrying out inverse mapping on the constellation points in the primary demodulation data according to the inverse function of the codebook mapping function, and carrying out secondary demodulation on the mapping result to obtain the original coded data. The method adjusts the encryption rotation and de-rotation steps of constellation rotation to the code domain through codebook design, the transceiver and the receiver only need to directly execute inner synchronization operation on the limited constellation points of the prior constellation diagram, and de-rotate the mapping codebook in the code domain to decrypt the original data, thereby solving the problem that constellation de-rotation and synchronization algorithm are incompatible, needing no additional synchronization design and reducing the difficulty of hardware realization.

Description

Constellation rotation encryption method based on codebook mapping and constellation expansion

Technical Field

The application relates to the technical field of digital transmission encryption, in particular to a constellation rotation encryption method based on codebook mapping and constellation expansion.

Background

Constellation rotation techniques are used at the modulation end to implement encryption of symbol constellations to ensure secure communication at the physical layer. Taking QPSK as an example, in the non-encryption QPSK transmission scheme, the receiving side can adjust the sampling position by estimating the carrier frequency difference and phase difference from the sampling information, and estimating the timing error. The synchronization algorithm is called as an internal synchronization method, synchronization can be realized by constructing an error feedback loop through sampling data under the condition of not needing additional pilot frequency information, the frequency spectrum utilization rate is high, and the method is widely practical in the communication field. After constellation rotation encryption is performed on QPSK, the regularity of a constellation diagram is destroyed, so that the problem that the constellation rotation technology is incompatible with a classical synchronization algorithm occurs. Specifically, in a signal received by a receiver, an encryption operation is coupled with a carrier error and a timing synchronization error, and a conventional algorithm cannot be used to obtain a data start point position and a local carrier frequency, correct the frequency difference and the phase of the carrier frequency of a sender, or adjust the position of an optimal sampling point, so that a key position corresponding to a current sampling point cannot be determined when constellation de-rotation is performed, thereby causing error decryption and making loop locking difficult.

To solve this problem, an external synchronization method, i.e., a method of achieving synchronization using only non-data symbols, may be employed. There are two significant disadvantages to this approach: firstly, a synchronization sequence with a large proportion is needed to ensure the alignment of initial data symbols and the calibration of the position of a sampling point; and secondly, extra external synchronization design is needed to extract carrier frequency. Both of these disadvantages will significantly reduce the rate of data transmission.

Disclosure of Invention

In view of the foregoing, it is desirable to provide a constellation rotation encryption method based on codebook mapping and constellation expansion, which can implement constellation rotation encryption while maintaining data transmission rate.

A constellation rotation encryption method based on codebook mapping and constellation expansion comprises,

at a data sending end:

and carrying out first phase shift keying modulation on the coded data to obtain corresponding first modulation data.

And performing second phase shift keying modulation on the primary modulation data according to a preset codebook mapping function to obtain corresponding secondary modulation data, so that each constellation point in the primary modulation data is mapped to a plurality of constellation points in the secondary modulation data.

At the data receiving end:

and demodulating the secondary modulation data to obtain corresponding primary demodulation data.

And mapping the constellation points in the primary demodulation data according to the inverse function of the codebook mapping function to obtain a corresponding mapping result.

And demodulating the mapping result to obtain the coded data.

In one embodiment, the obtaining manner of the codebook mapping function includes:

obtaining a rotation angle variable based on a random key algorithm;

and obtaining the mapping relation of the constellation in the primary modulation data and the secondary modulation data according to the rotation angle variable.

In one embodiment, performing second-time phase shift keying modulation on the primary modulation data according to a preset codebook mapping function to obtain corresponding secondary modulation data, and a manner of mapping each constellation point in the primary modulation data to a plurality of constellation points in the secondary modulation data includes:

and according to the preset initial mapping codebook data and the value of the rotation angle variable, obtaining the number of rotation lines when the constellation points in the primary modulation data are mapped to the second-order constellation points in the secondary modulation data.

In one embodiment, the manner of obtaining the rotation angle variable based on the random key algorithm includes:

and for each symbol in the encoded data, obtaining a corresponding rotation angle variable value based on a random key algorithm.

In one embodiment, before the step of demodulating the secondary modulation data to obtain the corresponding primary demodulation data, the method further includes:

and carrying out carrier synchronization and timing synchronization on the received data to obtain a corresponding baseband signal, and obtaining secondary modulation data according to the baseband signal.

In one embodiment, the manner of mapping each constellation point in the primary modulation data to a plurality of constellation points in the secondary modulation data includes:

each constellation point in the primary modulation data is mapped to a plurality of constellation points in the secondary modulation data according to compliance with a gray mapping rule.

A constellation rotation encryption device based on codebook mapping and constellation expansion comprises:

and the primary modulation module is used for carrying out primary phase shift keying modulation on the coded data to obtain corresponding primary modulation data.

And the secondary modulation module is used for carrying out secondary phase shift keying modulation on the primary modulation data according to a preset codebook mapping function to obtain corresponding secondary modulation data, so that each constellation point in the primary modulation data is mapped to a plurality of constellation points in the secondary modulation data.

And the primary demodulation module is used for demodulating the secondary modulation data to obtain corresponding primary demodulation data.

And the inverse mapping module is used for mapping the constellation points in the primary demodulation data according to the inverse function of the codebook mapping function to obtain a corresponding mapping result.

And the secondary demodulation module is used for demodulating the mapping result to obtain the coded data.

A constellation rotation encryption system based on codebook mapping and constellation expansion comprises a data sending end and a data receiving end.

The data sending end is used for carrying out first phase shift keying modulation on the coded data to obtain corresponding first modulation data, carrying out second phase shift keying modulation on the first modulation data according to a preset codebook mapping function to obtain corresponding second modulation data, and enabling each constellation point in the first modulation data to be mapped to a plurality of constellation points in the second modulation data.

The data receiving end is used for demodulating the secondary modulation data to obtain corresponding primary demodulation data, mapping the constellation points in the primary demodulation data according to the inverse function of the codebook mapping function to obtain corresponding mapping results, and demodulating the mapping results to obtain coded data.

A computer device comprising a memory and a processor, the memory storing a computer program, the processor implementing the following steps when executing the computer program:

at a data sending end:

At the data receiving end:

And demodulating the mapping result to obtain the coded data.

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

at a data sending end:

At the data receiving end:

And demodulating the mapping result to obtain the coded data.

Compared with the prior art, the constellation rotation encryption method, device, system, computer equipment and storage medium based on codebook mapping and constellation expansion are characterized in that at a data sending end: firstly, the coded data is subjected to primary phase shift keying modulation, and each constellation point in the primary modulation data is mapped to a plurality of constellation points according to a codebook mapping function, so that secondary phase shift keying modulation is completed. At the data receiving end: and demodulating the secondary modulation data, carrying out inverse mapping on the constellation points in the primary demodulation data according to the inverse function of the codebook mapping function, and carrying out secondary demodulation on the mapping result to obtain the original coded data. According to the method, the steps of encryption rotation and de-rotation of constellation rotation are adjusted to the code domain for processing through codebook design, the receiving and transmitting parties only need to directly execute inner synchronization operation on the limited constellation points of the existing constellation diagram, the mapping codebook is de-rotated in the code domain, and the original data can be decrypted, so that the problem that constellation de-rotation and a synchronization algorithm are incompatible is solved, extra synchronization design is not needed, and the difficulty of hardware realization is reduced.

Drawings

Fig. 1 is a diagram illustrating steps of a constellation rotation encryption method based on codebook mapping and constellation expansion in an embodiment, where a represents method steps performed at a data transmitting end, and b represents method steps performed at a data receiving end;

fig. 2 is a schematic diagram of a data processing flow of a data sending end in an embodiment;

FIG. 3 is a schematic diagram illustrating a data processing flow at a data receiving end according to an embodiment;

fig. 4 is a constellation diagram for BPSK, QPSK, and 8 PSK;

FIG. 5 is a diagram of an original mapping codebook from QPSK to 8PSK in one embodiment;

FIG. 6 is a diagram illustrating a QPSK to 8PSK codebook mapping function defined based on an original mapping codebook in one embodiment;

FIG. 7 is a diagram of an original mapping codebook from QPSK to 16PSK in one embodiment;

FIG. 8 is a diagram illustrating a QPSK to 16PSK codebook mapping function defined based on an original mapping codebook in one embodiment;

fig. 9 is a diagram illustrating a mapping manner from a QPSK constellation to an 8PSK constellation according to gray mapping in an embodiment;

fig. 10 is a diagram illustrating a mapping manner from a QPSK constellation to a 16PSK constellation according to gray mapping in one embodiment;

FIG. 11 is a diagram illustrating an internal structure of a computer device in one 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.

In one embodiment, a constellation rotation encryption method based on codebook mapping and constellation expansion is provided:

at the data sending end shown in fig. 2, the specific steps are shown as a in fig. 1, and include:

step 202, performing a first phase shift keying modulation on the encoded data to obtain corresponding primary modulation data.

And 204, performing second phase shift keying modulation on the primary modulation data according to a preset codebook mapping function to obtain corresponding secondary modulation data, so that each constellation point in the primary modulation data is mapped to a plurality of constellation points in the secondary modulation data.

At the data receiving end shown in fig. 3, the specific steps are shown as b in fig. 1, and include:

step 302, demodulating the secondary modulation data to obtain corresponding primary demodulation data.

And step 304, mapping the constellation points in the primary demodulation data according to the inverse function of the codebook mapping function to obtain a corresponding mapping result.

Step 306, the mapping result is demodulated to obtain the encoded data.

In this embodiment, the first phase shift keying modulation of the data sending end adopts QPSK, and the second phase shift keying modulation adopts 8 PSK. Firstly, to weaveThe coded data is QPSK modulated. The QPSK signal can be viewed as being formed by the BPSK superposition of two orthogonal carriers, each symbol containing 2bit of information, with the phases shared

Four states. The constellations for BPSK, QPSK and 8PSK are shown in fig. 4.

The method comprises the following steps of carrying out second time phase shift keying modulation on primary modulation data at a transmitting end according to a preset codebook mapping function, and obtaining corresponding secondary modulation data according to the following principle: the primary modulated data of each symbol needs to be encrypted by a rotary encryption module. Therefore, the signal of the transmitting end can be expressed as:

wherein, the sign before cos and sin is determined by the 2bit information corresponding to each code element,

indicating the rotation angle of all sample points within the same symbol for the rotation angles of constellation points in QPSK

The values are the same. Further, the rotation angle is for different symbols

May vary.

Considering that the channel is an additive white gaussian noise channel, and considering the power loss, the signal at the receiving end can be represented as:

wherein the content of the first and second substances,

representing the phase shift of the signal generated during transmission.

In an ideal situation, the rotation angle of the constellation diagram may be from 0 to

This changes the constellation diagram at the receiving end from a square constellation to a chaotic circular constellation. However, since there should be a limited value in digital communication. In order to be able to recover the constellation at the receiving end, the rotation angle must be quantized at the transmitting end. Suppose that the maximum sampling point that a hardware device can achieve in one symbol period is

Then subject to quantization

Wherein

. Therefore, the maximum point number of the quantization rotation constellation diagram under the condition of no noise at the transmitting end is

。

In this embodiment, QPSK mapping to 8PSK is selected. 8PSK signals adopt 8 phases to represent 8 states of a 3-bit code element, and the phase states are respectively

. The codebook mapping function is used to determine the mapping relationship between QPSK and 8PSK, and can be expressed as:

wherein

Indicates the angle of rotationM denotes the number of constellation points in MPSK modulation, and M =8 in the present embodiment.

Representing a mapping rotation function according to

The value of (a) is to rotate the original mapping codebook by the corresponding number of rows in the specified direction. The original mapping codebook in this embodiment is shown in fig. 5. As shown in fig. 6, for symbols in QPSK, when

If yes, the mapping relation is the same as the original mapping codebook, namely 00 is mapped into 000 or 001; when in use

Then, the mapping is performed by rotating one line downward with respect to the original mapping codebook, i.e., 00 is mapped to 001 or 011.

And the mapping mode when other values are taken is analogized. Fig. 7 and 8 also show the original mapping codebook and the rotation mapping scheme when mapping QPSK to 16PSK for M = 8. And mapping the QPSK into 8PSK according to a codebook mapping function to obtain corresponding secondary modulation data, and then carrying out up-conversion on the secondary modulation data and transmitting the secondary modulation data through a wireless channel.

The demodulation parameters of the data receiving end and the modulation parameters of the data sending end are correspondingly set, and carrier synchronization and timing synchronization are carried out through a synchronization loop during demodulation to obtain the MPSK signals sampled by a baseband. Then, original data is restored according to the inverse function of the codebook mapping function, that is, the original mapping codebook is subjected to the inverse operation of the rotation encryption module, the operation is realized by the inverse rotation decryption module, and the action can be expressed as:

where the input variable x represents every b undecrypted bits. The exponential-1 of the mapping function represents the inverse of the mapping function. For MPSK, the number of bits that can be demodulated per symbol is:

when M =8, b = 3. The 3-bit data corresponding to each symbol can be mapped into 2-bit data corresponding to QPSK according to the inverse function, and then the required coded data can be obtained by corresponding demodulation.

In the method provided by the embodiment, the two parties of the transceiver can establish the secret communication only by determining the original mapping codebook and the codebook mapping function, and when an eavesdropper cannot obtain the correct codebook mapping relation, correct data cannot be recovered. The method does not need additional synchronous design, and reduces the difficulty of hardware realization.

In one embodiment, the obtaining manner of the codebook mapping function includes: and obtaining the rotation angle variable based on a random key algorithm.

In particular, the amount of the solvent to be used,

in

The value of (a) is determined by a random key, and the data transmitting end and the data receiving end use the same random key generator for mapping and inverse mapping. Relative to what has been specified in advance

And the value sequence is selected, and the confidentiality of the codebook mapping function obtained based on the random key is higher.

Further, the codebook mapping function generates the rotation angle variable value for each symbol in the encoded data individually based on a random key algorithm, i.e. the codebook mapping function generates the rotation angle variable value for each symbol in the encoded data based on a random key algorithm

The value of (c).

Specifically, as shown in fig. 9 and 10, one constellation point is mapped to a plurality of adjacent constellation points during mapping, so that only one bit is different between adjacent mappings, i.e., gray mapping is followed. This allows the noise margin not to be significantly degraded by the increase in M.

It should be understood that, although the steps in the flowchart of fig. 1 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 a portion of the steps in fig. 1 may include multiple sub-steps or multiple stages that are not necessarily performed at the same time, but may be performed at different times, and the order of performance of the sub-steps or stages is not necessarily sequential, but may be performed in turn or alternately with other steps or at least a portion of the sub-steps or stages of other steps.

In one embodiment, a constellation rotation encryption apparatus based on codebook mapping and constellation expansion is provided, which includes:

In one embodiment, the apparatus further includes a codebook mapping function setting module, configured to: obtaining a rotation angle variable based on a random key algorithm; and obtaining the mapping relation of the constellation in the primary modulation data and the secondary modulation data according to the rotation angle variable.

In one embodiment, the secondary modulation module is configured to obtain, according to preset initial mapping codebook data and according to a value of the rotation angle variable, a number of rotation lines when the constellation point in the primary modulation data is mapped to a second-order constellation point in the secondary modulation data.

In one embodiment, the codebook mapping function setting module is configured to obtain, for each symbol in the encoded data, a corresponding rotation angle variable value based on a random key algorithm.

In one embodiment, the apparatus further includes a synchronization loop module, configured to perform carrier synchronization and timing synchronization on the received data to obtain a corresponding baseband signal, and obtain secondary modulation data according to the baseband signal.

In one embodiment, the secondary modulation module is configured to map each constellation point in the primary modulation data to a plurality of constellation points in the secondary modulation data according to a rule complying with gray mapping.

For specific limitation of a constellation rotation encryption device based on codebook mapping and constellation expansion, refer to the above limitation of a constellation rotation encryption method based on codebook mapping and constellation expansion, which is not described herein again. Each module in the constellation rotation encryption device based on codebook mapping and constellation expansion can be wholly or partially realized 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, which may be a server, and its internal structure diagram may be as shown in fig. 11. The computer device includes a processor, a memory, a network interface, and a database connected by a system bus. Wherein the processor of the computer device is configured 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 the original mapping codebook and the codebook mapping function 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 constellation rotation encryption method based on codebook mapping and constellation expansion.

Those skilled in the art will appreciate that the architecture shown in fig. 11 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 memory storing a computer program and a processor implementing the following steps when the processor executes the computer program:

at a data sending end:

At the data receiving end:

And demodulating the mapping result to obtain the coded data.

In one embodiment, the processor, when executing the computer program, further performs the steps of: obtaining a rotation angle variable based on a random key algorithm; and obtaining the mapping relation of the constellation in the primary modulation data and the secondary modulation data according to the rotation angle variable.

In one embodiment, the processor, when executing the computer program, further performs the steps of: and according to the preset initial mapping codebook data and the value of the rotation angle variable, obtaining the number of rotation lines when the constellation points in the primary modulation data are mapped to the second-order constellation points in the secondary modulation data.

In one embodiment, the processor, when executing the computer program, further performs the steps of: and for each symbol in the encoded data, obtaining a corresponding rotation angle variable value based on a random key algorithm.

In one embodiment, the processor, when executing the computer program, further performs the steps of: and carrying out carrier synchronization and timing synchronization on the received data to obtain a corresponding baseband signal, and obtaining secondary modulation data according to the baseband signal.

In one embodiment, the processor, when executing the computer program, further performs the steps of: each constellation point in the primary modulation data is mapped to a plurality of constellation points in the secondary modulation data according to compliance with a gray mapping rule.

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:

at a data sending end:

At the data receiving end:

And demodulating the mapping result to obtain the coded data.

In one embodiment, the computer program when executed by the processor further performs the steps of: obtaining a rotation angle variable based on a random key algorithm; and obtaining the mapping relation of the constellation in the primary modulation data and the secondary modulation data according to the rotation angle variable.

In one embodiment, the computer program when executed by the processor further performs the steps of: and according to the preset initial mapping codebook data and the value of the rotation angle variable, obtaining the number of rotation lines when the constellation points in the primary modulation data are mapped to the second-order constellation points in the secondary modulation data.

In one embodiment, the computer program when executed by the processor further performs the steps of: and for each symbol in the encoded data, obtaining a corresponding rotation angle variable value based on a random key algorithm.

In one embodiment, the computer program when executed by the processor further performs the steps of: and carrying out carrier synchronization and timing synchronization on the received data to obtain a corresponding baseband signal, and obtaining secondary modulation data according to the baseband signal.

In one embodiment, the computer program when executed by the processor further performs the steps of: each constellation point in the primary modulation data is mapped to a plurality of constellation points in the secondary modulation data according to compliance with a gray mapping rule.

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 related to 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 may include non-volatile and/or volatile memory, among others. Non-volatile memory can include read-only memory (ROM), Programmable ROM (PROM), Electrically Programmable ROM (EPROM), Electrically Erasable Programmable ROM (EEPROM), or flash memory. Volatile memory can include Random Access Memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in a variety of forms such as Static RAM (SRAM), Dynamic RAM (DRAM), Synchronous DRAM (SDRAM), Double Data Rate SDRAM (DDRSDRAM), Enhanced SDRAM (ESDRAM), Synchronous Link DRAM (SLDRAM), Rambus Direct RAM (RDRAM), direct bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

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 examples 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 constellation rotation encryption method based on codebook mapping and constellation expansion is characterized in that the method comprises the following steps,

at a data sending end:

carrying out first phase shift keying modulation on the coded data to obtain corresponding first modulation data;

performing second phase shift keying modulation on the primary modulation data according to a preset codebook mapping function to obtain corresponding secondary modulation data, so that each constellation point in the primary modulation data is mapped to a plurality of constellation points in the secondary modulation data;

at the data receiving end:

demodulating the secondary modulation data to obtain corresponding primary demodulation data;

mapping the constellation points in the primary demodulation data according to the inverse function of the codebook mapping function to obtain a corresponding mapping result;

demodulating the mapping result to obtain the coded data;

the codebook mapping function obtaining method includes:

obtaining a rotation angle variable based on a random key algorithm;

2. The method according to claim 1, wherein performing second-time phase shift keying modulation on the primary modulation data according to a preset codebook mapping function to obtain corresponding secondary modulation data, and a manner of mapping each constellation point in the primary modulation data to a plurality of constellation points in the secondary modulation data includes:

and according to preset initial mapping codebook data and the value of the rotation angle variable, obtaining the number of rotation lines when the constellation points in the primary modulation data are mapped to second-order constellation points in the secondary modulation data.

3. The method of claim 1, wherein obtaining the rotation angle variable based on a random key algorithm comprises:

4. The method according to claim 1, wherein before the step of demodulating the secondary modulated data to obtain the corresponding primary demodulated data, the method further comprises:

and carrying out carrier synchronization and timing synchronization on the received data to obtain a corresponding baseband signal, and obtaining the secondary modulation data according to the baseband signal.

5. The method according to any one of claims 1 to 4, wherein the mapping each constellation point in the primary modulation data to a plurality of constellation points in the secondary modulation data comprises:

mapping each constellation point in the primary modulation data to a plurality of constellation points in the secondary modulation data according to obeying a gray mapping rule.