Non-orthogonal coding method based on color-coded four-dimensional constellation pairing mapping

Abstract

The application discloses a non-orthogonal coding method based on color coding four-dimensional constellation pairing mapping, which combines 4D constellation pairing mapping and two-dimensional inverse discrete Fresnel transform (2D-IDFnT) and is highly compatible with an OFDM system, so that modulation and demodulation can be performed by using an existing OFDM system.The application explores a method for pairing mapping of four-dimensional space primitives based on color coding according to different quadrants, constructs the fourth dimension on the basis of a three-dimensional constellation through color coding, and realizes a four-dimensional constellation diagram design with a high gain exponent.Further, a non-orthogonal multiple access technology is used to superimpose multiple power signals to realize multiple access.The designed four-dimensional constellation design based on color coding improves the order of the NOMA constellation diagram from the perspective of expanding dimensions, solves the problem that the improvement of the order of the constellation diagram increases the reception error rate, and improves the system transmission performance.

Description

Technical Field

[0001] The present invention relates to a non-orthogonal coding method based on color-coded four-dimensional constellation pairing mapping, and belongs to the technical field of optical communication coding. Background Art

[0002] In today's rapidly developing digital age, information technology has permeated every aspect of society, leading to an increasing demand for high-speed, stable, and intelligent network connections. With the rise of the Internet of Things (IoT), a wide variety of smart devices, such as smart homes, smart cars, and industrial sensors, are emerging. These devices require network connectivity for data transmission and interaction. However, existing access networks are increasingly struggling to cope with this large and diverse array of connected devices. Passive optical networks (PONs), with their efficient bandwidth utilization, wide coverage, and relatively low cost, have become a core technology for modern optical access networks. Since the early days of time-division multiplexing (TDM-PON), PON technology has undergone numerous innovations and evolutions. In addition to traditional TDM-PON, wavelength-division multiplexing (WDM-PON) and orthogonal frequency-division multiplexing (OFDM-PON) have also become mainstream solutions, further improving network capacity and transmission efficiency. However, future development requires PON systems to incorporate optimized modulation schemes to better meet growing user demands and emerging application scenarios.

[0003] In recent years, orthogonal chirp multiplexing (OCDM) has gained increasing popularity in optical fiber communication systems. As an emerging multi-carrier modulation technology, its complexity is similar to OFDM, but its performance is superior. OCDM modulates a signal onto a large number of orthogonally chirped subcarriers and transmits them in superposition. Its excellent pulse compression and spectrum spreading capabilities effectively mitigate frequency-selective fading. Consequently, compared to OFDM, OCDM exhibits stronger interference immunity and a shorter cyclic prefix (CP) while maintaining comparable spectral efficiency. The core structure of OCDM consists of constellation mapping and inverse discrete Fresnel transform. Constellation mapping converts the input bit sequence into a complex signal, representing data differences through the positions of the constellation points. The design of the constellation directly affects the signal's power distribution, information mapping dimension, and interference mitigation. Increasing the information mapping dimension, or in other words, the dimensionality of the constellation, significantly increases the diversity of information representation. The direct detection-orthogonal chirp multiplexing (DD-OCDM) short-distance optical transmission method based on four-dimensional constellation mapping extends traditional OCDM to four-dimensional space, improves the utilization of constellation space, and increases the minimum Euclidean distance (MED) of constellation points under the same transmission power conditions, showing a significant bit error rate improvement compared to two-dimensional or three-dimensional constellations.

[0004] Although four-dimensional OCDM (4D-OCDM) effectively improves system transmission performance, it still fundamentally requires strict orthogonality between different chirped subcarriers. To meet the comprehensive coverage and large-scale access expectations of 5G, non-orthogonal multiple access (NOMA) technology has become a research hotspot. By superimposing the signals of multiple users on the same resource block, NOMA breaks the independence of traditional access methods, achieving higher spectral efficiency and accommodating more users. However, existing solutions are mostly based on low-dimensional constellation mapping, which still suffers from insufficient anti-interference capabilities and low low-dimensional constellation capacity.

[0005] Therefore, how to optimize the design of four-dimensional NOMA, constellation structure and mapping rules, and implement related high-dimensional NOMA solutions is a technical problem that technical personnel in this field urgently need to solve. Summary of the Invention

[0006] Objective: To overcome the shortcomings of the prior art, the present invention provides a non-orthogonal encoding method based on color-coded four-dimensional constellation pairing mapping and designs a 4D-NOMA method based on color-coded four-dimensional constellation pairing mapping. The color-coded four-dimensional constellation pairing mapping can combine the four-dimensional constellation geometry design with NOMA, and can improve the CFM (Constellation Figure of Merit) of the constellation to enhance system performance.

[0007] Technical solution: To solve the above technical problems, the technical solution adopted by the present invention is:

[0008] In a first aspect, a non-orthogonal encoding method based on color-coded four-dimensional constellation pairing mapping specifically includes:

[0009] In an optical communication transmission system, a binary information sequence Date1 is converted into M parallel binary sequences of Date1 through serial-to-parallel conversion, where M represents the number of subcarriers.

[0010] In an optical communication transmission system, a binary information sequence Date2 is converted into M parallel Date2 binary sequences through serial-to-parallel conversion, where M represents the number of subcarriers.

[0011] Perform four-dimensional constellation mapping on the binary sequence of parallel Date1 to obtain the 4D-constellation point vector of Date1.

[0012] Perform four-dimensional constellation mapping on the binary sequence of parallel Date2 to obtain the 4D-constellation point vector of Date2.

[0013] The M 4D-constellation point vectors of Date1 are combined into an OCDM symbol of Date1.

[0014] The M 4D-constellation point vectors of Date2 are combined into an OCDM symbol of Date2.

[0015] Perform two-dimensional inverse discrete Fresnel transform on the OCDM symbol of Date 1 and the OCDM symbol of Date 2 to obtain a time domain signal of Date 1 and a time domain signal of Date 2.

[0016] A cyclic prefix is ​​added to the time domain signal of Date1 and then converted into a first channel signal sequence through serial-to-parallel conversion. A cyclic prefix is ​​added to the time domain signal of Date2 and then converted into a second channel signal sequence through serial-to-parallel conversion. The first channel signal sequence and the second channel signal sequence are superimposed to obtain an OCDM baseband signal.

[0017] The OCDM baseband signal is digitally up-converted to obtain a 4D-NOMA signal.

[0018] As a preferred solution, performing four-dimensional constellation mapping on the binary sequence of parallel Date1 to obtain the 4D-constellation point vector of Date1 specifically includes:

[0019] Step 1.1: Get M parallel binary sequences of Date1.

[0020] Step 1.2: Set each binary sequence of Date1 to 2 bits.

[0021] Step 1.3: Perform constellation mapping according to 3D-QPSK based on the data in the binary sequence of each Date1 to obtain the constellation coordinate points of the binary sequence of each Date1.

[0022] Step 1.4: Add 0 after the constellation coordinate point of each binary sequence of Date1 to obtain the 4D-constellation point vector of each binary sequence of Date1.

[0023] As a preferred solution, the step 1.3 specifically includes:

[0024] Step 1.3.1: When the data in the binary sequence of Date1 is 00, according to the constellation mapping rule of 3D-QPSK, the coordinates of the constellation coordinate point of the binary sequence of Date1 are (1, 0, 1).

[0025] Step 1.3.2: When the data in the binary sequence of Date1 is 01, according to the constellation mapping rule of 3D-QPSK, the coordinates of the constellation coordinate point of the binary sequence of Date1 are (-1, 0, 1).

[0026] Step 1.3.3: When the data in the binary sequence of Date1 is 11, according to the constellation mapping rule of 3D-QPSK, the coordinates of the constellation coordinate point of the binary sequence of Date1 are (-1, 0, -1).

[0027] Step 1.3.4: When the data in the binary sequence of Date1 is 10, according to the constellation mapping rule of 3D-QPSK, the coordinates of the constellation coordinate point of the binary sequence of Date1 are (1, 0, -1).

[0028] As a preferred solution, performing four-dimensional constellation mapping on the binary sequence of parallel Date2 to obtain the 4D-constellation point vector of Date2 specifically includes:

[0029] Step 2.1: Get M parallel binary sequences of Date2.

[0030] Step 2.2: Set the binary sequence of each Date2 to 3 bits.

[0031] Step 2.3: Pair a 2-bit group with the binary sequence of Date2, where the data of the 2-bit group includes: 00, 01, 11 or 10.

[0032] Step 2.4: According to the binary sequence of Date2 corresponding to a 2-bit group, according to the four-dimensional constellation mapping, a 4D-constellation point vector of the binary sequence of Date2 is obtained.

[0033] As a preferred solution, the step 2.4 specifically includes:

[0034] Step 2.4.1: When the data in a 2-bit group is 00, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 000 in the corresponding binary sequence of Date2 is (-0.7071, 1, -0.7071, 1).

[0035] Step 2.4.2: When the data in a 2-bit group is 00, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 001 in the corresponding binary sequence of Date2 is (-0.7071, -1, -0.7071, 1).

[0036] Step 2.4.3: When the data in a 2-bit group is 00, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 011 in the corresponding binary sequence of Date2 is (0.7071, 1, 0.7071, 1).

[0037] Step 2.4.4: When the data in a 2-bit group is 00, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 010 in the corresponding binary sequence of Date2 is (0.7071, -1, 0.7071, 1).

[0038] Step 2.4.5: When the data in a 2-bit group is 00, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 110 in the corresponding binary sequence of Date2 is (0.7071, -1, 0.7071, -1).

[0039] Step 2.4.6: When the data in a 2-bit group is 00, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 111 in the corresponding binary sequence of Date2 is (0.7071, 1, 0.7071, -1).

[0040] Step 2.4.7: When the data in a 2-bit group is 00, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 101 in the corresponding binary sequence of Date2 is (-0.7071, -1, -0.7071, -1).

[0041] Step 2.4.8: When the data in a 2-bit group is 00, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 100 in the corresponding binary sequence of Date2 is (-0.7071, 1, -0.7071, -1).

[0042] Step 2.4.9: When the data in a 2-bit group is 01, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 000 in the corresponding binary sequence of Date2 is (0.7071, 1, -0.7071, 1).

[0043] Step 2.4.10: When the data in a 2-bit group is 01, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 001 in the corresponding binary sequence of Date2 is (0.7071, -1, -0.7071, 1).

[0044] Step 2.4.11: When the data in a 2-bit group is 01, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 011 in the corresponding binary sequence of Date2 is (-0.7071, 1, 0.7071, 1).

[0045] Step 2.4.12: When the data in a 2-bit group is 01, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 010 in the corresponding binary sequence of Date2 is (-0.7071, -1, 0.7071, 1).

[0046] Step 2.4.13: When the data in a 2-bit group is 01, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 110 in the corresponding binary sequence of Date2 is (-0.7071, -1, 0.7071, -1).

[0047] Step 2.4.14: When the data in a 2-bit group is 01, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 111 in the corresponding binary sequence of Date2 is (-0.7071, 1, 0.7071, -1).

[0048] Step 2.4.15: When the data in a 2-bit group is 01, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 101 in the corresponding binary sequence of Date2 is (0.7071, -1, -0.7071, -1).

[0049] Step 2.4.16: When the data in a 2-bit group is 01, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 100 in the corresponding binary sequence of Date2 is (0.7071, 1, -0.7071, -1).

[0050] Step 2.4.17: When the data in a 2-bit group is 10, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 000 in the corresponding binary sequence of Date2 is (-0.7071, 1, 0.7071, 1).

[0051] Step 2.4.18: When the data in a 2-bit group is 10, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 001 in the corresponding binary sequence of Date2 is (-0.7071, -1, 0.7071, 1).

[0052] Step 2.4.19: When the data in a 2-bit group is 10, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 011 in the corresponding binary sequence of Date2 is (0.7071, 1, -0.7071, 1).

[0053] Step 2.4.20: When the data in a 2-bit group is 10, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 010 in the corresponding binary sequence of Date2 is (0.7071, -1, -0.7071, 1).

[0054] Step 2.4.21: When the data in a 2-bit group is 10, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 110 in the corresponding binary sequence of Date2 is (0.7071, -1, -0.7071, -1).

[0055] Step 2.4.22: When the data in a 2-bit group is 10, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 111 in the corresponding binary sequence of Date2 is (0.7071, 1, -0.7071, -1).

[0056] Step 2.4.23: When the data in a 2-bit group is 10, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 101 in the corresponding binary sequence of Date2 is (-0.7071, -1, 0.7071, -1).

[0057] Step 2.4.24: When the data in a 2-bit group is 10, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 100 in the corresponding binary sequence of Date2 is (-0.7071, 1, 0.7071, -1).

[0058] Step 2.4.25: When the data in a 2-bit group is 11, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 000 in the corresponding binary sequence of Date2 is (0.7071, 1, 0.7071, 1).

[0059] Step 2.4.26: When the data in a 2-bit group is 11, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 001 in the corresponding binary sequence of Date2 is (0.7071, -1, 0.7071, 1).

[0060] Step 2.4.27: When the data in a 2-bit group is 11, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 011 in the corresponding binary sequence of Date2 is (-0.7071, 1, -0.7071, 1).

[0061] Step 2.4.28: When the data in a 2-bit group is 11, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 010 in the corresponding binary sequence of Date2 is (-0.7071, -1, -0.7071, 1).

[0062] Step 2.4.29: When the data in a 2-bit group is 11, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 110 in the corresponding binary sequence of Date2 is (-0.7071, -1, -0.7071, -1).

[0063] Step 2.4.30: When the data in a 2-bit group is 11, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 111 in the corresponding binary sequence of Date2 is (-0.7071, 1, -0.7071, -1).

[0064] Step 2.4.31: When the data in a 2-bit group is 11, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 101 in the corresponding binary sequence of Date2 is (0.7071, -1, 0.7071, -1).

[0065] Step 2.4.32: When the data in a 2-bit group is 11, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 100 in the corresponding binary sequence of Date2 is (0.7071, 1, 0.7071, -1).

[0066] The 1 in the fourth dimension of the 4D-constellation point vector represents one color, and the -1 in the fourth dimension of the 4D-constellation point vector represents another color.

[0067] As a preferred solution, the step 2.4 specifically includes:

[0068] Step 2.4.1: When the data in a 2-bit group is 00, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 000 in the corresponding binary sequence of Date2 is (-0.5774, 1, -0.8164, 1).

[0069] Step 2.4.2: When the data in a 2-bit group is 00, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 001 in the corresponding binary sequence of Date2 is (-0.5774, -1, -0.8164, 1).

[0070] Step 2.4.3: When the data in a 2-bit group is 00, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 011 in the corresponding binary sequence of Date2 is (1.7321, 0, 0.8164, 1).

[0071] Step 2.4.4: When the data in a 2-bit group is 00, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 010 in the corresponding binary sequence of Date2 is (0, 0, 0.8164, 1).

[0072] Step 2.4.5: When the data in a 2-bit group is 00, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 110 in the corresponding binary sequence of Date2 is (0, 0, 0.8164, -1).

[0073] Step 2.4.6: When the data in a 2-bit group is 00, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 111 in the corresponding binary sequence of Date2 is (1.7321, 0, -0.8164, -1).

[0074] Step 2.4.7: When the data in a 2-bit group is 00, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 101 in the corresponding binary sequence of Date2 is (-0.5774, -1, -0.8164, -1).

[0075] Step 2.4.8: When the data in a 2-bit group is 00, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 100 in the corresponding binary sequence of Date2 is (-0.5774, 1, -0.8164, -1).

[0076] Step 2.4.9: When the data in a 2-bit group is 01, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 000 in the corresponding binary sequence of Date2 is (-0.5774, 1, -0.8164, 1).

[0077] Step 2.4.10: When the data in a 2-bit group is 01, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 001 in the corresponding binary sequence of Date2 is (-0.5774, -1, -0.8164, 1).

[0078] Step 2.4.11: When the data in a 2-bit group is 01, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 011 in the corresponding binary sequence of Date2 is (1.7321, 0, 0.8164, 1).

[0079] Step 2.4.12: When the data in a 2-bit group is 01, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 010 in the corresponding binary sequence of Date2 is (0, 0, 0.8164, 1).

[0080] Step 2.4.13: When the data in a 2-bit group is 01, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 110 in the corresponding binary sequence of Date2 is (0, 0, 0.8164, -1).

[0081] Step 2.4.14: When the data in a 2-bit group is 01, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 111 in the corresponding binary sequence of Date2 is (1.7321, 0, -0.8164, -1).

[0082] Step 2.4.15: When the data in a 2-bit group is 01, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 101 in the corresponding binary sequence of Date2 is (-0.5774, -1, -0.8164, -1).

[0083] Step 2.4.16: When the data in a 2-bit group is 01, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 100 in the corresponding binary sequence of Date2 is (-0.5774, 1, -0.8164, -1).

[0084] Step 2.4.17: When the data in a 2-bit group is 10, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 000 in the corresponding binary sequence of Date2 is (-0.5774, 1, -0.8164, 1).

[0085] Step 2.4.18: When the data in a 2-bit group is 10, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 001 in the corresponding binary sequence of Date2 is (-0.5774, -1, -0.8164, 1).

[0086] Step 2.4.19: When the data in a 2-bit group is 10, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 011 in the corresponding binary sequence of Date2 is (1.7321, 0, 0.8164, 1).

[0087] Step 2.4.20: When the data in a 2-bit group is 10, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 010 in the corresponding binary sequence of Date2 is (0, 0, 0.8164, 1).

[0088] Step 2.4.21: When the data in a 2-bit group is 10, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 110 in the corresponding binary sequence of Date2 is (0, 0, 0.8164, -1).

[0089] Step 2.4.22: When the data in a 2-bit group is 10, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 111 in the corresponding binary sequence of Date2 is (1.7321, 0, -0.8164, -1).

[0090] Step 2.4.23: When the data in a 2-bit group is 10, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 101 in the corresponding binary sequence of Date2 is (-0.5774, -1, -0.8164, -1).

[0091] Step 2.4.24: When the data in a 2-bit group is 10, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 100 in the corresponding binary sequence of Date2 is (-0.5774, 1, -0.8164, -1).

[0092] Step 2.4.25: When the data in a 2-bit group is 11, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 000 in the corresponding binary sequence of Date2 is (-0.5774, 1, -0.8164, 1).

[0093] Step 2.4.26: When the data in a 2-bit group is 11, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 001 in the corresponding binary sequence of Date2 is (-0.5774, -1, -0.8164, 1).

[0094] Step 2.4.27: When the data in a 2-bit group is 11, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 011 in the corresponding binary sequence of Date2 is (1.7321, 0, 0.8164, 1).

[0095] Step 2.4.28: When the data in a 2-bit group is 11, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 010 in the corresponding binary sequence of Date2 is (0, 0, 0.8164, 1).

[0096] Step 2.4.29: When the data in a 2-bit group is 11, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 110 in the corresponding binary sequence of Date2 is (0, 0, 0.8164, -1).

[0097] Step 2.4.30: When the data in a 2-bit group is 11, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 111 in the corresponding binary sequence of Date2 is (1.7321, 0, -0.8164, -1).

[0098] Step 2.4.31: When the data in a 2-bit group is 11, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 101 in the corresponding binary sequence of Date2 is (-0.5774, -1, -0.8164, -1).

[0099] Step 2.4.32: When the data in a 2-bit group is 11, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 100 in the corresponding binary sequence of Date2 is (-0.5774, 1, -0.8164, -1).

[0100] The 1 in the fourth dimension of the 4D-constellation point vector represents one color, and the -1 in the fourth dimension of the 4D-constellation point vector represents another color.

[0101] As a preferred solution, the OCDM symbol calculation formula is as follows:

[0102]

[0103] Among them, S 4D Indicates OCDM symbols, G1, G2, G n , G M Represent the 1st, 2nd, nth, and Mth 4D-constellation point vectors respectively.

[0104] Where,

[0105] Among them, G x，n , G y，n , G z，n and G f，n The vectors representing the x, y, z and f dimensions of the n-th 4D-constellation point vector respectively.

[0106] As a preferred solution, the calculation formula of the time domain signal T is as follows:

[0107]

[0108] in,

[0109]

[0110] k1 and k2 are the k1 and k2 rows of the DFnT matrix, respectively. -1 represents the 4×4 inverse IFFT matrix, H M -1 Represents the M×M inverse IFFT matrix.

[0111] As a preferred solution, the calculation formula of the OCDM baseband signal is as follows:

[0112]

[0113] Wherein, s(n) is the OCDM baseband signal, T1”(t) represents the first channel signal sequence, T2”(t) represents the second channel signal sequence, P1 represents the high power ratio, P2 represents the low power ratio, and P1+P2=1.

[0114] As a preferred solution, the calculation formula of 4D-NOMA signal is as follows:

[0115]

[0116] Among them, s DUC (n) is the 4D-NOMA signal, f is the frequency of the mixing signal, f s is the sampling frequency, s I (n) represents the real part of the OCDM signal, s Q (n) represents the imaginary part of the OCDM signal.

[0117] In a second aspect, a transmitting end is provided, configured to execute a non-orthogonal coding method based on color-coded four-dimensional constellation pairing mapping in the first aspect.

[0118] Beneficial effects: The present invention provides a non-orthogonal coding method based on color-coded four-dimensional constellation pairing mapping, and the method of the present invention realizes flexible optical access based on 4D-NOMA. The proposed method combines 4D constellation pairing mapping with two-dimensional inverse discrete Fresnel transform (2D-IDFnT), is highly compatible with the OFDM system, and can be modulated and demodulated using the existing OFDM system. An innovative exploration of the pairing mapping method of four-dimensional space primitives based on color coding was conducted, and two four-dimensional space structures of 32 constellation points were designed. Compared with the three-dimensional square constellation, the four-dimensional constellation expansion increases the capacity of the constellation points by 22.2%, and better system performance can be obtained.

[0119] This solution innovatively explores a method for pairing and mapping four-dimensional spatial primitives based on color coding according to different quadrants. By constructing a fourth dimension based on the three-dimensional constellation through color coding, it achieves a four-dimensional constellation design with a high gain index. Furthermore, multi-power signals are superimposed through non-orthogonal multiple access technology to achieve multi-path access. This color-coded four-dimensional constellation design increases the order of the NOMA constellation by expanding the dimensionality, resolving the issue of increased bit error rate associated with increased constellation order and improving system transmission performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0120] Figure 1 Flowchart of a non-orthogonal encoding method based on color-coded four-dimensional constellation pairing mapping.

[0121] Figure 2 Schematic diagram of 4D-NOMA constellation design based on color coding, where: Figure 2 (a) is a schematic diagram of the constellation mapping of 4D-NOMA1. Figure 2 (b) is a schematic diagram of the constellation mapping of 4D-NOMA2.

[0122] Figure 3 Schematic diagram of the bit error rate curve of MOMA schemes in different dimensions at the receiving end.

[0123] Figure 4 The figure is a schematic diagram comparing the bit error rate curves of various schemes under different optical powers. DETAILED DESCRIPTION

[0124] The following is a clear and complete description of the technical solutions in the examples of the present invention, in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative work are within the scope of protection of the present invention.

[0125] The present invention will be further described below with reference to specific embodiments.

[0126] Example 1:

[0127] This embodiment introduces a non-orthogonal encoding method based on color-coded four-dimensional constellation pairing mapping, such as Figure 1 As shown, specifically including:

[0128] In an optical communication transmission system, a binary information sequence Date1 is converted into M parallel binary sequences of Date1 through serial-to-parallel conversion, where M represents the number of subcarriers.

[0129] In an optical communication transmission system, a binary information sequence Date2 is converted into M parallel Date2 binary sequences through serial-to-parallel conversion, where M represents the number of subcarriers.

[0130] Perform four-dimensional constellation mapping on the binary sequence of parallel Date1 to obtain the 4D-constellation point vector of Date1.

[0131] Perform four-dimensional constellation mapping on the binary sequence of parallel Date2 to obtain the 4D-constellation point vector of Date2.

[0132] The M 4D-constellation point vectors of Date1 are combined into an OCDM symbol of Date1.

[0133] The M 4D-constellation point vectors of Date2 are combined into an OCDM symbol of Date2.

[0134] Perform two-dimensional inverse discrete Fresnel transform on the OCDM symbol of Date 1 and the OCDM symbol of Date 2 to obtain a time domain signal of Date 1 and a time domain signal of Date 2.

[0135] A cyclic prefix is ​​added to the time domain signal of Date1 and then converted into a first channel signal sequence through serial-to-parallel conversion. A cyclic prefix is ​​added to the time domain signal of Date2 and then converted into a second channel signal sequence through serial-to-parallel conversion. The first channel signal sequence and the second channel signal sequence are superimposed to obtain an OCDM baseband signal.

[0136] The OCDM baseband signal is digitally up-converted to obtain a 4D-NOMA signal.

[0137] Furthermore, the four-dimensional constellation mapping of the binary sequence of the parallel Date1 to obtain the 4D-constellation point vector of Date1 specifically includes:

[0138] Step 1.1: Get M parallel binary sequences of Date1.

[0139] Step 1.2: Set each binary sequence of Date1 to 2 bits.

[0140] Step 1.3: Perform constellation mapping according to 3D-QPSK based on the data in the binary sequence of each Date1 to obtain the constellation coordinate points of the binary sequence of each Date1.

[0141] Step 1.4: Add 0 after the constellation coordinate point of each binary sequence of Date1 to obtain the 4D-constellation point vector of each binary sequence of Date1.

[0142] Furthermore, the step 1.3 specifically includes:

[0143] Step 1.3.1: When the data in the binary sequence of Date1 is 00, according to the constellation mapping rule of 3D-QPSK, the coordinates of the constellation coordinate point of the binary sequence of Date1 are (1, 0, 1).

[0144] Step 1.3.2: When the data in the binary sequence of Date1 is 01, according to the constellation mapping rule of 3D-QPSK, the coordinates of the constellation coordinate point of the binary sequence of Date1 are (-1, 0, 1).

[0145] Step 1.3.3: When the data in the binary sequence of Date1 is 11, according to the constellation mapping rule of 3D-QPSK, the coordinates of the constellation coordinate point of the binary sequence of Date1 are (-1, 0, -1).

[0146] Step 1.3.4: When the data in the binary sequence of Date1 is 10, according to the constellation mapping rule of 3D-QPSK, the coordinates of the constellation coordinate point of the binary sequence of Date1 are (1, 0, -1).

[0147] Furthermore, the four-dimensional constellation mapping of the binary sequence of the parallel Date2 to obtain the 4D-constellation point vector of Date2 specifically includes:

[0148] Step 2.1: Get M parallel binary sequences of Date2.

[0149] Step 2.2: Set the binary sequence of each Date2 to 3 bits.

[0150] Step 2.3: Pair a 2-bit group with the binary sequence of Date2, where the data of the 2-bit group includes: 00, 01, 11 or 10.

[0151] Step 2.4: According to the binary sequence of Date2 corresponding to a 2-bit group, according to the four-dimensional constellation mapping, a 4D-constellation point vector of the binary sequence of Date2 is obtained.

[0152] Furthermore, the step 2.4 specifically includes:

[0153] Step 2.4.1: When the data in a 2-bit group is 00, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 000 in the corresponding binary sequence of Date2 is (-0.7071, 1, -0.7071, 1).

[0154] Step 2.4.2: When the data in a 2-bit group is 00, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 001 in the corresponding binary sequence of Date2 is (-0.7071, -1, -0.7071, 1).

[0155] Step 2.4.3: When the data in a 2-bit group is 00, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 011 in the corresponding binary sequence of Date2 is (0.7071, 1, 0.7071, 1).

[0156] Step 2.4.4: When the data in a 2-bit group is 00, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 010 in the corresponding binary sequence of Date2 is (0.7071, -1, 0.7071, 1).

[0157] Step 2.4.5: When the data in a 2-bit group is 00, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 110 in the corresponding binary sequence of Date2 is (0.7071, -1, 0.7071, -1).

[0158] Step 2.4.6: When the data in a 2-bit group is 00, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 111 in the corresponding binary sequence of Date2 is (0.7071, 1, 0.7071, -1).

[0159] Step 2.4.7: When the data in a 2-bit group is 00, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 101 in the corresponding binary sequence of Date2 is (-0.7071, -1, -0.7071, -1).

[0160] Step 2.4.8: When the data in a 2-bit group is 00, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 100 in the corresponding binary sequence of Date2 is (-0.7071, 1, -0.7071, -1).

[0161] Step 2.4.9: When the data in a 2-bit group is 01, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 000 in the corresponding binary sequence of Date2 is (0.7071, 1, -0.7071, 1).

[0162] Step 2.4.10: When the data in a 2-bit group is 01, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 001 in the corresponding binary sequence of Date2 is (0.7071, -1, -0.7071, 1).

[0163] Step 2.4.11: When the data in a 2-bit group is 01, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 011 in the corresponding binary sequence of Date2 is (-0.7071, 1, 0.7071, 1).

[0164] Step 2.4.12: When the data in a 2-bit group is 01, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 010 in the corresponding binary sequence of Date2 is (-0.7071, -1, 0.7071, 1).

[0165] Step 2.4.13: When the data in a 2-bit group is 01, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 110 in the corresponding binary sequence of Date2 is (-0.7071, -1, 0.7071, -1).

[0166] Step 2.4.14: When the data in a 2-bit group is 01, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 111 in the corresponding binary sequence of Date2 is (-0.7071, 1, 0.7071, -1).

[0167] Step 2.4.15: When the data in a 2-bit group is 01, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 101 in the corresponding binary sequence of Date2 is (0.7071, -1, -0.7071, -1).

[0168] Step 2.4.16: When the data in a 2-bit group is 01, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 100 in the corresponding binary sequence of Date2 is (0.7071, 1, -0.7071, -1).

[0169] Step 2.4.17: When the data in a 2-bit group is 10, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 000 in the corresponding binary sequence of Date2 is (-0.7071, 1, 0.7071, 1).

[0170] Step 2.4.18: When the data in a 2-bit group is 10, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 001 in the corresponding binary sequence of Date2 is (-0.7071, -1, 0.7071, 1).

[0171] Step 2.4.19: When the data in a 2-bit group is 10, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 011 in the corresponding binary sequence of Date2 is (0.7071, 1, -0.7071, 1).

[0172] Step 2.4.20: When the data in a 2-bit group is 10, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 010 in the corresponding binary sequence of Date2 is (0.7071, -1, -0.7071, 1).

[0173] Step 2.4.21: When the data in a 2-bit group is 10, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 110 in the corresponding binary sequence of Date2 is (0.7071, -1, -0.7071, -1).

[0174] Step 2.4.22: When the data in a 2-bit group is 10, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 111 in the corresponding binary sequence of Date2 is (0.7071, 1, -0.7071, -1).

[0175] Step 2.4.23: When the data in a 2-bit group is 10, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 101 in the corresponding binary sequence of Date2 is (-0.7071, -1, 0.7071, -1).

[0176] Step 2.4.24: When the data in a 2-bit group is 10, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 100 in the corresponding binary sequence of Date2 is (-0.7071, 1, 0.7071, -1).

[0177] Step 2.4.25: When the data in a 2-bit group is 11, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 000 in the corresponding binary sequence of Date2 is (0.7071, 1, 0.7071, 1).

[0178] Step 2.4.26: When the data in a 2-bit group is 11, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 001 in the corresponding binary sequence of Date2 is (0.7071, -1, 0.7071, 1).

[0179] Step 2.4.27: When the data in a 2-bit group is 11, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 011 in the corresponding binary sequence of Date2 is (-0.7071, 1, -0.7071, 1).

[0180] Step 2.4.28: When the data in a 2-bit group is 11, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 010 in the corresponding binary sequence of Date2 is (-0.7071, -1, -0.7071, 1).

[0181] Step 2.4.29: When the data in a 2-bit group is 11, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 110 in the corresponding binary sequence of Date2 is (-0.7071, -1, -0.7071, -1).

[0182] Step 2.4.30: When the data in a 2-bit group is 11, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 111 in the corresponding binary sequence of Date2 is (-0.7071, 1, -0.7071, -1).

[0183] Step 2.4.31: When the data in a 2-bit group is 11, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 101 in the corresponding binary sequence of Date2 is (0.7071, -1, 0.7071, -1).

[0184] Step 2.4.32: When the data in a 2-bit group is 11, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 100 in the corresponding binary sequence of Date2 is (0.7071, 1, 0.7071, -1).

[0185] The 1 in the fourth dimension of the 4D-constellation point vector represents one color, and the -1 in the fourth dimension of the 4D-constellation point vector represents another color.

[0186] Furthermore, the step 2.4 specifically includes:

[0187] Step 2.4.1: When the data in a 2-bit group is 00, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 000 in the corresponding binary sequence of Date2 is (-0.5774, 1, -0.8164, 1).

[0188] Step 2.4.2: When the data in a 2-bit group is 00, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 001 in the corresponding binary sequence of Date2 is (-0.5774, -1, -0.8164, 1).

[0189] Step 2.4.3: When the data in a 2-bit group is 00, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 011 in the corresponding binary sequence of Date2 is (1.7321, 0, 0.8164, 1).

[0190] Step 2.4.4: When the data in a 2-bit group is 00, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 010 in the corresponding binary sequence of Date2 is (0, 0, 0.8164, 1).

[0191] Step 2.4.5: When the data in a 2-bit group is 00, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 110 in the corresponding binary sequence of Date2 is (0, 0, 0.8164, -1).

[0192] Step 2.4.6: When the data in a 2-bit group is 00, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 111 in the corresponding binary sequence of Date2 is (1.7321, 0, -0.8164, -1).

[0193] Step 2.4.7: When the data in a 2-bit group is 00, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 101 in the corresponding binary sequence of Date2 is (-0.5774, -1, -0.8164, -1).

[0194] Step 2.4.8: When the data in a 2-bit group is 00, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 100 in the corresponding binary sequence of Date2 is (-0.5774, 1, -0.8164, -1).

[0195] Step 2.4.9: When the data in a 2-bit group is 01, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 000 in the corresponding binary sequence of Date2 is (-0.5774, 1, -0.8164, 1).

[0196] Step 2.4.10: When the data in a 2-bit group is 01, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 001 in the corresponding binary sequence of Date2 is (-0.5774, -1, -0.8164, 1).

[0197] Step 2.4.11: When the data in a 2-bit group is 01, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 011 in the corresponding binary sequence of Date2 is (1.7321, 0, 0.8164, 1).

[0198] Step 2.4.12: When the data in a 2-bit group is 01, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 010 in the corresponding binary sequence of Date2 is (0, 0, 0.8164, 1).

[0199] Step 2.4.13: When the data in a 2-bit group is 01, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 110 in the corresponding binary sequence of Date2 is (0, 0, 0.8164, -1).

[0200] Step 2.4.14: When the data in a 2-bit group is 01, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 111 in the corresponding binary sequence of Date2 is (1.7321, 0, -0.8164, -1).

[0201] Step 2.4.15: When the data in a 2-bit group is 01, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 101 in the corresponding binary sequence of Date2 is (-0.5774, -1, -0.8164, -1).

[0202] Step 2.4.16: When the data in a 2-bit group is 01, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 100 in the corresponding binary sequence of Date2 is (-0.5774, 1, -0.8164, -1).

[0203] Step 2.4.17: When the data in a 2-bit group is 10, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 000 in the corresponding binary sequence of Date2 is (-0.5774, 1, -0.8164, 1).

[0204] Step 2.4.18: When the data in a 2-bit group is 10, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 001 in the corresponding binary sequence of Date2 is (-0.5774, -1, -0.8164, 1).

[0205] Step 2.4.19: When the data in a 2-bit group is 10, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 011 in the corresponding binary sequence of Date2 is (1.7321, 0, 0.8164, 1).

[0206] Step 2.4.20: When the data in a 2-bit group is 10, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 010 in the corresponding binary sequence of Date2 is (0, 0, 0.8164, 1).

[0207] Step 2.4.21: When the data in a 2-bit group is 10, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 110 in the corresponding binary sequence of Date2 is (0, 0, 0.8164, -1).

[0208] Step 2.4.22: When the data in a 2-bit group is 10, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 111 in the corresponding binary sequence of Date2 is (1.7321, 0, -0.8164, -1).

[0209] Step 2.4.23: When the data in a 2-bit group is 10, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 101 in the corresponding binary sequence of Date2 is (-0.5774, -1, -0.8164, -1).

[0210] Step 2.4.24: When the data in a 2-bit group is 10, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 100 in the corresponding binary sequence of Date2 is (-0.5774, 1, -0.8164, -1).

[0211] Step 2.4.25: When the data in a 2-bit group is 11, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 000 in the corresponding binary sequence of Date2 is (-0.5774, 1, -0.8164, 1).

[0212] Step 2.4.26: When the data in a 2-bit group is 11, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 001 in the corresponding binary sequence of Date2 is (-0.5774, -1, -0.8164, 1).

[0213] Step 2.4.27: When the data in a 2-bit group is 11, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 011 in the corresponding binary sequence of Date2 is (1.7321, 0, 0.8164, 1).

[0214] Step 2.4.28: When the data in a 2-bit group is 11, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 010 in the corresponding binary sequence of Date2 is (0, 0, 0.8164, 1).

[0215] Step 2.4.29: When the data in a 2-bit group is 11, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 110 in the corresponding binary sequence of Date2 is (0, 0, 0.8164, -1).

[0216] Step 2.4.30: When the data in a 2-bit group is 11, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 111 in the corresponding binary sequence of Date2 is (1.7321, 0, -0.8164, -1).

[0217] Step 2.4.31: When the data in a 2-bit group is 11, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 101 in the corresponding binary sequence of Date2 is (-0.5774, -1, -0.8164, -1).

[0218] Step 2.4.32: When the data in a 2-bit group is 11, according to the second rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 100 in the corresponding binary sequence of Date2 is (-0.5774, 1, -0.8164, -1).

[0219] The 1 in the fourth dimension of the 4D-constellation point vector represents one color, and the -1 in the fourth dimension of the 4D-constellation point vector represents another color.

[0220] Furthermore, the OCDM symbol calculation formula is as follows:

[0221]

[0222] Among them, S 4D Indicates OCDM symbols, G1, G2, G n , G M Represent the 1st, 2nd, nth, and Mth 4D-constellation point vectors respectively.

[0223] Where,

[0224] Among them, G x，n , G y，n , G z，n and G f，n The vectors representing the x, y, z and f dimensions of the n-th 4D-constellation point vector respectively.

[0225] Furthermore, the calculation formula of the time domain signal T is as follows:

[0226]

[0227] in,

[0228]

[0229]

[0230] k1 and k2 are the k1 and k2 rows of the DFnT matrix, respectively. -1 represents the 4×4 inverse IFFT matrix, H M -1 Represents the M×M inverse IFFT matrix.

[0231] Furthermore, the calculation formula of the OCDM baseband signal is as follows:

[0232]

[0233] Wherein, s(n) is the OCDM baseband signal, T1”(t) represents the first channel signal sequence, T2”(t) represents the second channel signal sequence, P1 represents the high power ratio, P2 represents the low power ratio, and P1+P2=1.

[0234] Furthermore, the calculation formula of 4D-NOMA signal is as follows:

[0235]

[0236] Among them, s DUC(n) is the 4D-NOMA signal, f is the frequency of the mixing signal, f s is the sampling frequency, s I (n) represents the real part of the OCDM signal, s Q (n) represents the imaginary part of the OCDM signal.

[0237] Example 2:

[0238] This embodiment introduces a transmitting end, which is used to execute the non-orthogonal encoding method based on color-coded four-dimensional constellation pairing mapping in Embodiment 1.

[0239] Example 3:

[0240] This embodiment introduces the working principle of a non-orthogonal encoding method based on color-coded four-dimensional constellation pairing mapping, such as Figure 1 As shown in the figure, in an optical communication transmission system, two binary information sequences undergo serial-to-parallel (S / P) conversion, and the original data bit stream is converted into M parallel binary sequences, where M represents the number of subcarriers. Each binary sequence is mapped through a 4D constellation. The mapped 4D constellation generates a time-domain chirp signal using a two-dimensional inverse discrete Fresnel transform (2D-IDFnT). After adding a CP (cyclic prefix), the generated OCDM (complex orthogonal chirp multiplexing) baseband signal is digitally up-converted (DUC) to obtain a 4D-NOMA signal. Finally, the 4D-NOMA signal enters the channel for transmission.

[0241] Human perception and thinking are mainly limited to the three-dimensional world. Therefore, we can directly design three-dimensional constellations in three-dimensional space, but it is difficult to intuitively imagine and design the characteristics of super-dimensional constellations beyond three dimensions. This makes it difficult to conceive and depict the structure and layout that conforms to the four-dimensional constellation space when designing a four-dimensional constellation. However, we can deduce from low dimensions to high dimensions and approach a better design structure.

[0242] For example, the four-dimensional constellation can be constructed by adding three dimensions to one dimension or two dimensions to two dimensions. In the present invention, starting from the perspective of 3D constellation design, a dimension is added to the 3D constellation and color coding is used to represent the constellation points of the fourth dimension, symbolizing the density of the specific position of the signal in a certain three-dimensional space. The four-dimensional constellation design is completed through the construction of the fourth dimension. Based on the above four-dimensional constellation construction method based on color coding and the new 4D constellation pairing mapping rule, the present invention proposes the following Figure 2 The two 4D-NOMA schemes in (a) and (b) are shown in Table 1. The mapping rules and four-dimensional constellation coordinates of the two schemes at different power levels are shown in Table 1. The high power ratio is P1, the low power ratio is P2, P1 + P2 = 1 and P1 > P1, the high power ratio corresponds to the signal Date1, and the low power ratio corresponds to the signal Date2.

[0243] The signal corresponding to high-power P1 uses a QPSK (Quadrature Phase Shift Keying)-like constellation distribution in the XOZ plane of three-dimensional space. A paired mapping scheme is implemented for the constellation points of the signal corresponding to low-power P2. Specifically, different mapping rules are designed based on the constellation points in different quadrants of the high-power signal. Four mapping rules, Case 1 through Case 4, correspond to the four quadrants of the P1 signal. Each mapping rule has eight constellation points, resulting in a total of 4 × 8 = 32 constellation points. The corresponding mapping rules are shown in Table 1. The data before the brackets in the table represent the bits before mapping, and the data in the brackets represent the coordinates of the corresponding bits after mapping.

[0244] Because the four-dimensional construction method proposed in this invention uses color coding to construct the fourth dimension based on the three-dimensional constellation, the low-power signal is based on the standard three-dimensional space square distribution structure as the primitive superimposed color dimension. The 4D-NOMA1 constellation after the superposition of the two signals is as follows: Figure 2 As shown in (a), the minimum Euclidean distance of the constellation points is set to 2. It can be found that the final constellation diagram is similar to the overlap of two traditional three-dimensional constellations in the four-dimensional space. In order to further utilize the low-power point resources, 4D-NOMA2 is designed, as shown in Figure 2 As shown in (b) of Figure 2, the high-power signal still uses a QPSK constellation distribution on the XOZ plane in three-dimensional space. To maximize the minimum Euclidean distance (MED) of the constellation, the low-power signal uses a tetrahedron-based structure. The constellation distribution of the tetrahedron elements is determined by the quadrant distribution of the high-power signal. Table 1 shows the mapping rules for the high-power and low-power signals.

[0245] Table 1 4D NOMA four-dimensional mapping rules

[0246]

[0247]

[0248] Since the mapping method of the constellation points is no longer the traditional two-dimensional constellation signal, the four-dimensional constellation requires 2D-IDFnT (two-dimensional inverse discrete Fresnel transform) to obtain the time domain signal. After S / P, the signal on the nth subcarrier can be expressed as:

[0249]

[0250] G x，n , G y，n , G z，n and G f，nRepresent the x, y, z and f-dimensional vectors of the 4D constellation points respectively. The OCDM symbol in the frequency domain can be represented by a set of M chirped subcarrier signals, expressed as:

[0251]

[0252] After 4D constellation mapping, the frequency-domain OCDM symbols are converted into time-domain chirp signals through 2D-IDFnT.

[0253]

[0254] Where (k1, k2) represents the k1th row and k2th column of the DFnT matrix, and Ψ1 and Ψ2 are given by the following two equations respectively:

[0255]

[0256] It can be seen from equation (3) that 2D-IDFnT is implemented by performing 1D-IDFnT twice. Therefore, 2D-IDFnT can be simplified to:

[0257]

[0258] Among them H4 -1 and H M -1 Represent the 4×4 and M×M inverse IFFT matrices respectively. It can be seen that the generation and recovery of OCDM signals can be implemented using the existing OFDM system, which has high compatibility. After 2D-IDFnT, the time domain signal can be expressed as:

[0259]

[0260] The generated time domain signal is serialized into

[0261] T1"=[t 11 t 11 ...t 1M t 21 t 22 ...t 2M t 31 t 32 ...t 3M t 41 t 42 ...t 4M ] (8)

[0263] Similarly, the time domain signal T2 corresponding to the signal with small power ratio can be calculated.

[0264] The proposed 4D-NOMA is obtained by superimposing different power levels in the digital domain. The superimposed signal can be expressed as:

[0265]

[0266] T2”(t) represents the signal sequence of the second different channel.

[0267] Since the IM / DD experimental system can only transmit real signals, and the existence of phase matrices Ψ1 and Ψ2 during OCDM modulation means that DFnT no longer has the conjugate symmetry property of discrete Fresnel transform (DFT), DUC technology is used to convert the 4D-NOMA complex signal modulated by 2D-IDFnT into a real signal for transmission in the IM-DD system. The DUC process for the baseband 4D-NOMA signal can be expressed as:

[0268]

[0269] Where f is the frequency of the mixing signal, f s is the sampling frequency, s I (n) represents the real part of the OCDM signal, s Q (n) represents the imaginary part of the OCDM signal. DUC (n) is the band 4 D-NOMA signal after DUC. It can be seen that the real and imaginary parts of the OCDM signal can be mixed into the real part of the composite signal through DUC, and then transmitted through the IM / DD system.

[0270] The present invention designs a three-dimensional constellation by expanding outward, so that the constellation points converge as much as possible inward, constructing a three-dimensional geometric structure with the minimum average energy of the constellation points. Then, by color-coding and superimposing the fourth dimension, a four-dimensional constellation design is achieved, improving the constellation's CFM. The mapped modulated signal is then transformed into a time-domain chirp signal using a two-dimensional inverse discrete Fresnel transform (2D-IDFnT). The signals of multiple users are then superimposed on the same resource block using the NOMA technique, achieving higher spectral efficiency and accommodating more users. The 4D-NOMA signal is transmitted through the channel. At the receiver, the received superimposed signal is first decoded and restored into two signals using the successive interference cancellation (SIC) technique. The original information is then restored by performing a 2D discrete Fresnel transform (2D-DFT) and demodulating.

[0271] Example 4:

[0272] This embodiment introduces the verification process of the method of the present invention. Since the final NOMA constellation is composed of the superposition of signals of different energies, the performance of the constellation diagram after superposition is affected by the constellation MED and PDR of high-power and low-power signals. Therefore, we simulate and calculate the optimal PDR of NOMA constellations of different dimensions under the premise that the constellation MED before superposition is fixed at 2. We also calculate the MED and CFM of the NOMA constellation diagram under the optimal PDR. As shown in Table 2, it can be seen that the performance of 4D-NOMA is improved compared with 2D-NOMA and 3D-NOMA. In particular, 4D-NOMA2 fully utilizes the four-dimensional constellation space. Compared with the traditional 32-point square 3D-NOMA, the MED of the constellation points is improved by 11.8%, and the CFM is improved by 22.2%.

[0273] Table 2 Performance comparison of constellations of different dimensions before and after superposition at different powers

[0274]

[0275]

[0276] Where: average energy E avg , the minimum Euclidean distance (MED), and the gain factor (CFM) are indicators for measuring the performance of the constellation diagram. For the proposed 32-point 4D-NOMA constellation diagram, its average energy E avg for:

[0277]

[0278] Where: C(i) represents the i-th point in the 4D-NOMA constellation diagram, ||C(i)|| 2 Indicates the distance from the constellation point C(i) to the origin. E avg Related to the signal transmission power, E avg The increase in will lead to an increase in signal transmission power.

[0279] The minimum Euclidean distance MED of 32-point 4D-NOMA 4D It can be expressed as:

[0280] MED 4D =min{||C(i)-C(j)||2} i,j＝1,2...32∧j≠i (12)

[0281] CFM is usually used to comprehensively evaluate the performance of the constellation diagram. The gain index CFM of 32-point 4D-NOMA is 4D for:

[0282]

[0283] The coding method of the present invention is tested through DSP and seven-core optical fiber channel transmission. The bit error rate curve of the NOMA scheme signal based on different dimensional modulation formats is as follows: Figure 3 shown.

[0284] Among them, 4D-NOMA1 and 4D-NOMA2 constellations are the constellation designs proposed by the present invention, 2D-NOMA is a traditional two-dimensional 32QAM structure, 3D-NOMA is a three-dimensional NOMA scheme using a double cube distribution, and 2D-OFDM uses square 32QAM. Under the corresponding optimal power division ratio (PDR) conditions, the best PDR of 2D-NOMA is 4, the PDR of 3D-NOMA is 4, and the PDR of 4D-NOMA is 3. The signal transmission performance of these four schemes at different powers was tested. Figure 3 It can be seen that with the increase of optical power, the transmission performance of the four schemes has improved. In addition, due to the uneven power distribution, the transmission performance of high-power signals is significantly better than that of low-power signals. In all four schemes, the low-power signals first have bit errors at higher received optical powers. Under the HD-FEC threshold, the high-power signals of 2D-NOMA, 3D-NOMA, 4D-NOMA1 and 4D-NOMA2 achieve sensitivity gains of 1.0dB, 1.4dB, 0.9dB and 0.6dB respectively compared with their respective low-power signals. However, for both high-power and low-power signals, 4D-NOMA requires lower received optical power than 2D-NOMA and 3D-NOMA at the same bit error rate. Therefore, it can be predicted that 4D-NOMA will perform better than 2D-NOMA and 3D-NOMA. In addition, when using the same 4D constellation, the received optical power of 4D-NOMA1-P1 and 4D-NOMA2-P1 is similar, but 4D-NOMA2-P2 has a 0.3dB sensitivity gain compared to 4D-NOMA1-P2. This can be attributed to the fact that 4D-NOMA2 uses a regular tetrahedral element superposition constellation, which can have a larger CFM at the same transmit power.

[0285] Figure 4 The figure shows a comparison of the bit error rate curves of various schemes under different optical powers. Among them, 4D-OFDM and 4D-OCDM use a constellation similar to the superposition of 4D-NOMA1. The bit error rate curve here is the average bit error rate formed by the superposition of two signals. The results show that the NOMA scheme using 4D constellation has obvious performance than 2D-NOMA and 3D-NOMA. This is because the four-dimensional constellation has the advantage of spatial decision-making in constellation points. It has a larger MED under the same number of constellation points. Among them, the bit error rate of 4D-NOMA2 is -10.4dB, which is the best performance among the four schemes. -3At a bit error rate of 100 Mbps, 4D-NOMA2 achieves a sensitivity gain of 0.9 dB and 1.3 dB compared to 3D-NOMA and 2D-NOMA. It can also be noted that at high optical power, the performance difference between 4D-OCDM and 4D-NOMA is not significant. As the optical power decreases, 4D-OCDM outperforms 4D-NOMA. This can be attributed to the error propagation effect of the SIC algorithm, which affects the performance of the NOMA scheme. It can also be seen that 4D-OCDM and 4D-NOMA, both using 2D-IDFnT, outperform 4D-OFDM using 2D-IFFT. Compared to 2D-IFFT, the linear frequency modulation signal generated by 2D-IDFnT has stronger anti-interference capabilities, resulting in greater performance improvements and making the system more robust.

[0286] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A non-orthogonal encoding method based on color-coded four-dimensional constellation pairing mapping, characterized by: Specifically include: In an optical communication transmission system, a binary information sequence Date1 is converted into a binary sequence of M parallel Date1s through serial-to-parallel conversion, where M represents the number of subcarriers. In an optical communication transmission system, a binary information sequence Date2 is converted from serial to parallel into a binary sequence of M parallel Date2, where M represents the number of subcarriers. Perform four-dimensional constellation mapping on the binary sequence of parallel Date1 to obtain the 4D-constellation point vector of Date1; Perform four-dimensional constellation mapping on the binary sequence of parallel Date2 to obtain the 4D-constellation point vector of Date2; Combining M 4D-constellation point vectors of Date1 into OCDM symbols of Date1; Combining M 4D-constellation point vectors of Date2 into OCDM symbols of Date2; Performing two-dimensional inverse discrete Fresnel transform on the OCDM symbol of Date1 and the OCDM symbol of Date2 respectively to obtain the time domain signal of Date1 and the time domain signal of Date2; A cyclic prefix is ​​added to the time domain signal of Date1 and then converted into a first channel signal sequence by serial-to-parallel conversion. A cyclic prefix is ​​added to the time domain signal of Date2 and then converted into a second channel signal sequence by serial-to-parallel conversion. The first channel signal sequence and the second channel signal sequence are superimposed to obtain an OCDM baseband signal. The OCDM baseband signal is digitally up-converted to obtain a 4D-NOMA signal.

2. The non-orthogonal encoding method based on color-coded four-dimensional constellation pairing mapping according to claim 1, characterized in that: The process of performing four-dimensional constellation mapping on the binary sequence of the parallel Date1 to obtain the 4D-constellation point vector of Date1 specifically includes: Step 1.1: Get M parallel binary sequences of Date1; Step 1.2: Set the binary sequence of each Date1 to 2 bits; Step 1.3: Perform constellation mapping according to 3D-QPSK based on the data in the binary sequence of each Date1 to obtain the constellation coordinate points of the binary sequence of each Date1; Step 1.4: Add 0 after the constellation coordinate point of each binary sequence of Date1 to obtain the 4D-constellation point vector of each binary sequence of Date1.

3. The non-orthogonal encoding method based on color-coded four-dimensional constellation pairing mapping according to claim 2, characterized in that: The step 1.3 specifically includes: Step 1.3.1: When the data in the binary sequence of Date1 is 00, according to the constellation mapping rule of 3D-QPSK, the coordinates of the constellation coordinate point of the binary sequence of Date1 are (1, 0, 1); Step 1.3.2: When the data in the binary sequence of Date1 is 01, according to the constellation mapping rule of 3D-QPSK, the coordinates of the constellation coordinate point of the binary sequence of Date1 are (-1, 0, 1); Step 1.3.3: When the data in the binary sequence of Date1 is 11, according to the constellation mapping rule of 3D-QPSK, the coordinates of the constellation coordinate point of the binary sequence of Date1 are (-1, 0, -1); Step 1.3.4: When the data in the binary sequence of Date1 is 10, according to the constellation mapping rule of 3D-QPSK, the coordinates of the constellation coordinate point of the binary sequence of Date1 are (1, 0, -1).

4. The non-orthogonal encoding method based on color-coded four-dimensional constellation pairing mapping according to claim 1, characterized in that: The process of performing four-dimensional constellation mapping on the binary sequence of the parallel Date2 to obtain the 4D-constellation point vector of Date2 specifically includes: Step 2.1: Get M parallel Date2 binary sequences; Step 2.2: Set the binary sequence of each Date2 to 3 bits; Step 2.3: Pair a 2-bit group with the binary sequence of Date2, where the data of the 2-bit group includes: 00, 01, 11 or 10; Step 2.4: According to the binary sequence of Date2 corresponding to a 2-bit group, according to the four-dimensional constellation mapping, a 4D-constellation point vector of the binary sequence of Date2 is obtained.

5. The non-orthogonal encoding method based on color-coded four-dimensional constellation pairing mapping according to claim 4, characterized in that: The step 2.4 specifically includes: Step 2.4.1: When the data in a 2-bit group is 00, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 000 in the corresponding binary sequence of Date2 is (-0.7071, 1, -0.7071, 1); Step 2.4.2: When the data in a 2-bit group is 00, according to the first rule in the 4D constellation mapping, the 4D-constellation point vector of the data 001 in the corresponding binary sequence of Date2 is (-0.7071,-1,-0.7071,1); Step 2.4.3: When the data in a 2-bit group is 00, according to the first rule in the 4D constellation mapping, the 4D-constellation point vector of the data 011 in the corresponding binary sequence of Date2 is (0.7071, 1, 0.7071, 1); Step 2.4.4: When the data in a 2-bit group is 00, according to the first rule in the 4D constellation mapping, the 4D-constellation point vector of the data 010 in the corresponding binary sequence of Date2 is (0.7071, -1, 0.7071, 1); Step 2.4.5: When the data in a 2-bit group is 00, according to the first rule in the four-dimensional constellation mapping, the 4D-constellation point vector of the data 110 in the corresponding binary sequence of Date2 is (0.7071, -1, 0.7071, -1); Step 2.4.6: When the data in a 2-bit group is 00, according to the first rule in the 4D constellation mapping, the 4D-constellation point vector of the data 111 in the corresponding binary sequence of Date2 is (0.7071, 1, 0.7071, -1); Step 2.4.7: When the data in a 2-bit group is 00, according to the first rule in the 4D constellation mapping, the 4D-constellation point vector of the data 101 in the corresponding binary sequence of Date2 is (-0.7071,-1,-0.7071,-1); Step 2.4.8: When the data in a 2-bit group is 00, according to the first rule in the 4D constellation mapping, the 4D-constellation point vector of the data 100 in the corresponding binary sequence of Date2 is (-0.7071, 1, -0.7071, -1); Step 2.4.9: When the data in a 2-bit group is 01, according to the first rule in the 4D constellation mapping, the 4D-constellation point vector of the data 000 in the corresponding binary sequence of Date2 is (0.7071, 1, -0.7071, 1); Step 2.4.10: When the data in a 2-bit group is 01, according to the first rule in the 4D constellation mapping, the 4D-constellation point vector of the data 001 in the corresponding binary sequence of Date2 is (0.7071, -1, -0.7071, 1); Step 2.4.11: When the data in a 2-bit group is 01, according to the first rule in the 4D constellation mapping, the 4D-constellation point vector of the data 011 in the corresponding binary sequence of Date2 is (-0.7071, 1, 0.7071, 1); Step 2.4.12: When the data in a 2-bit group is 01, according to the first rule in the 4D constellation mapping, the 4D-constellation point vector of the data 010 in the corresponding binary sequence of Date2 is (-0.7071, -1, 0.7071, 1); Step 2.4.13: When the data in a 2-bit group is 01, according to the first rule in the 4D constellation mapping, the 4D-constellation point vector of the data 110 in the corresponding binary sequence of Date2 is (-0.7071, -1, 0.7071, -1); Step 2.4.14: When the data in a 2-bit group is 01, according to the first rule in the 4D constellation mapping, the 4D-constellation point vector of the data 111 in the corresponding binary sequence of Date2 is (-0.7071, 1, 0.7071, -1); Step 2.4.15: When the data in a 2-bit group is 01, according to the first rule in the 4D constellation mapping, the 4D-constellation point vector of the data 101 in the corresponding binary sequence of Date2 is (0.7071, -1, -0.7071, -1); Step 2.4.16: When the data in a 2-bit group is 01, according to the first rule in the 4D constellation mapping, the 4D-constellation point vector of the data 100 in the corresponding binary sequence of Date2 is (0.7071, 1, -0.7071, -1); Step 2.4.17: When the data in a 2-bit group is 10, according to the first rule in the 4D constellation mapping, the 4D-constellation point vector of the data 000 in the corresponding binary sequence of Date2 is (-0.7071, 1, 0.7071, 1); Step 2.4.18: When the data in a 2-bit group is 10, according to the first rule in the 4D constellation mapping, the 4D-constellation point vector of the data 001 in the corresponding binary sequence of Date2 is (-0.7071, -1, 0.7071, 1); Step 2.4.19: When the data in a 2-bit group is 10, according to the first rule in the 4D constellation mapping, the 4D-constellation point vector of the data 011 in the corresponding binary sequence of Date2 is (0.7071, 1, -0.7071, 1); Step 2.4.20: When the data in a 2-bit group is 10, according to the first rule in the 4D constellation mapping, the 4D-constellation point vector of the data 010 in the corresponding binary sequence of Date2 is (0.7071, -1, -0.7071, 1); Step 2.4.21: When the data in a 2-bit group is 10, according to the first rule in the 4D constellation mapping, the 4D-constellation point vector of the data 110 in the corresponding binary sequence of Date2 is (0.7071, -1, -0.7071, -1); Step 2.4.22: When the data in a 2-bit group is 10, according to the first rule in the 4D constellation mapping, the 4D-constellation point vector of the data 111 in the corresponding binary sequence of Date2 is (0.7071, 1, -0.7071, -1); Step 2.4.23: When the data in a 2-bit group is 10, according to the first rule in the 4D constellation mapping, the 4D-constellation point vector of the data 101 in the corresponding binary sequence of Date2 is (-0.7071, -1, 0.7071, -1); Step 2.4.24: When the data in a 2-bit group is 10, according to the first rule in the 4D constellation mapping, the 4D-constellation point vector of the data 100 in the corresponding binary sequence of Date2 is (-0.7071, 1, 0.7071, -1); Step 2.4.25: When the data in a 2-bit group is 11, according to the first rule in the 4D constellation mapping, the 4D-constellation point vector of the data 000 in the corresponding binary sequence of Date2 is (0.7071, 1, 0.7071, 1); Step 2.4.26: When the data in a 2-bit group is 11, according to the first rule in the 4D constellation mapping, the 4D-constellation point vector of the data 001 in the corresponding binary sequence of Date2 is (0.7071, -1, 0.7071, 1); Step 2.4.27: When the data in a 2-bit group is 11, according to the first rule in the 4D constellation mapping, the 4D-constellation point vector of the data 011 in the corresponding binary sequence of Date2 is (-0.7071, 1, -0.7071, 1); Step 2.4.28: When the data in a 2-bit group is 11, according to the first rule in the four-dimensional constellation mapping, the corresponding 4D-constellation point vector of the data 010 in the binary sequence of Date2 is (-0.7071, -1, -0.7071, 1); Step 2.4.29: When the data in a 2-bit group is 11, according to the first rule in the four-dimensional constellation mapping, the corresponding 4D-constellation point vector of the data 110 in the binary sequence of Date2 is (-0.7071, -1, -0.7071, -1); Step 2.4.30: When the data in a 2-bit group is 11, according to the first rule in the 4D constellation mapping, the 4D-constellation point vector of the data 111 in the corresponding binary sequence of Date2 is (-0.7071, 1, -0.7071, -1); Step 2.4.31: When the data in a 2-bit group is 11, according to the first rule in the 4D constellation mapping, the 4D-constellation point vector of the data 101 in the corresponding binary sequence of Date2 is (0.7071, -1, 0.7071, -1); Step 2.4.32: When the data in a 2-bit group is 11, according to the first rule in the 4D constellation mapping, the 4D-constellation point vector of the data 100 in the corresponding binary sequence of Date2 is (0.7071, 1, 0.7071, -1); The 1 in the fourth dimension of the 4D-constellation point vector represents one color, and the -1 in the fourth dimension of the 4D-constellation point vector represents another color.

6. The non-orthogonal encoding method based on color-coded four-dimensional constellation pairing mapping according to claim 4, characterized in that: The step 2.4 specifically includes: Step 2.4.1: When the data in a 2-bit group is 00, according to the second rule in the 4D constellation mapping, the 4D-constellation point vector of the data 000 in the corresponding binary sequence of Date2 is (-0.5774, 1, -0.8164, 1); Step 2.4.2: When the data in a 2-bit group is 00, according to the second rule in the 4D constellation mapping, the 4D-constellation point vector of the data 001 in the corresponding binary sequence of Date2 is (-0.5774, -1, -0.8164, 1); Step 2.4.3: When the data in a 2-bit group is 00, according to the second rule in the 4D constellation mapping, the 4D-constellation point vector of the data 011 in the corresponding binary sequence of Date2 is (1.7321, 0, 0.8164, 1); Step 2.4.4: When the data in a 2-bit group is 00, according to the second rule in the 4D constellation mapping, the 4D-constellation point vector of the data 010 in the corresponding binary sequence of Date2 is (0, 0, 0.8164, 1); Step 2.4.5: When the data in a 2-bit group is 00, according to the second rule in the 4D constellation mapping, the 4D-constellation point vector of the data 110 in the corresponding binary sequence of Date2 is (0, 0, 0.8164, -1); Step 2.4.6: When the data in a 2-bit group is 00, according to the second rule in the 4D constellation mapping, the 4D-constellation point vector of the data 111 in the corresponding binary sequence of Date2 is (1.7321, 0, -0.8164, -1); Step 2.4.7: When the data in a 2-bit group is 00, according to the second rule in the 4D constellation mapping, the 4D-constellation point vector of the data 101 in the corresponding binary sequence of Date2 is (-0.5774, -1, -0.8164, -1); Step 2.4.8: When the data in a 2-bit group is 00, according to the second rule in the 4D constellation mapping, the 4D-constellation point vector of the data 100 in the corresponding binary sequence of Date2 is (-0.5774, 1, -0.8164, -1); Step 2.4.9: When the data in a 2-bit group is 01, according to the second rule in the 4D constellation mapping, the 4D-constellation point vector of the data 000 in the corresponding binary sequence of Date2 is (-0.5774, 1, -0.8164, 1); Step 2.4.10: When the data in a 2-bit group is 01, according to the second rule in the 4D constellation mapping, the 4D-constellation point vector of the data 001 in the corresponding binary sequence of Date2 is (-0.5774, -1, -0.8164, 1); Step 2.4.11: When the data in a 2-bit group is 01, according to the second rule in the 4D constellation mapping, the 4D-constellation point vector of the data 011 in the corresponding binary sequence of Date2 is (1.7321, 0, 0.8164, 1); Step 2.4.12: When the data in a 2-bit group is 01, according to the second rule in the 4D constellation mapping, the 4D-constellation point vector of the data 010 in the corresponding binary sequence of Date2 is (0, 0, 0.8164, 1); Step 2.4.13: When the data in a 2-bit group is 01, according to the second rule in the 4D constellation mapping, the 4D-constellation point vector of the data 110 in the corresponding binary sequence of Date2 is (0, 0, 0.8164, -1); Step 2.4.14: When the data in a 2-bit group is 01, according to the second rule in the 4D constellation mapping, the 4D-constellation point vector of the data 111 in the corresponding binary sequence of Date2 is (1.7321, 0, -0.8164, -1); Step 2.4.15: When the data in a 2-bit group is 01, according to the second rule in the 4D constellation mapping, the 4D-constellation point vector of the data 101 in the corresponding binary sequence of Date2 is (-0.5774, -1, -0.8164, -1); Step 2.4.16: When the data in a 2-bit group is 01, according to the second rule in the 4D constellation mapping, the 4D-constellation point vector of the data 100 in the corresponding binary sequence of Date2 is (-0.5774, 1, -0.8164, -1); Step 2.4.17: When the data in a 2-bit group is 10, according to the second rule in the 4D constellation mapping, the 4D-constellation point vector of the data 000 in the corresponding binary sequence of Date2 is (-0.5774, 1, -0.8164, 1); Step 2.4.18: When the data in a 2-bit group is 10, according to the second rule in the 4D constellation mapping, the 4D-constellation point vector of the data 001 in the corresponding binary sequence of Date2 is (-0.5774, -1, -0.8164, 1); Step 2.4.19: When the data in a 2-bit group is 10, according to the second rule in the 4D constellation mapping, the 4D-constellation point vector of the data 011 in the corresponding binary sequence of Date2 is (1.7321, 0, 0.8164, 1); Step 2.4.20: When the data in a 2-bit group is 10, according to the second rule in the 4D constellation mapping, the 4D-constellation point vector of the data 010 in the corresponding binary sequence of Date2 is (0, 0, 0.8164, 1); Step 2.4.21: When the data in a 2-bit group is 10, according to the second rule in the 4D constellation mapping, the 4D-constellation point vector of the data 110 in the corresponding binary sequence of Date2 is (0, 0, 0.8164, -1); Step 2.4.22: When the data in a 2-bit group is 10, according to the second rule in the 4D constellation mapping, the 4D-constellation point vector of the data 111 in the corresponding binary sequence of Date2 is (1.7321, 0, -0.8164, -1); Step 2.4.23: When the data in a 2-bit group is 10, according to the second rule in the 4D constellation mapping, the 4D-constellation point vector of the data 101 in the corresponding binary sequence of Date2 is (-0.5774, -1, -0.8164, -1); Step 2.4.24: When the data in a 2-bit group is 10, according to the second rule in the 4D constellation mapping, the 4D-constellation point vector of the data 100 in the corresponding binary sequence of Date2 is (-0.5774, 1, -0.8164, -1); Step 2.4.25: When the data in a 2-bit group is 11, according to the second rule in the 4D constellation mapping, the 4D-constellation point vector of the data 000 in the corresponding binary sequence of Date2 is (-0.5774, 1, -0.8164, 1); Step 2.4.26: When the data in a 2-bit group is 11, according to the second rule in the 4D constellation mapping, the 4D-constellation point vector of the data 001 in the corresponding binary sequence of Date2 is (-0.5774, -1, -0.8164, 1); Step 2.4.27: When the data in a 2-bit group is 11, according to the second rule in the 4D constellation mapping, the 4D-constellation point vector of the data 011 in the corresponding binary sequence of Date2 is (1.7321, 0, 0.8164, 1); Step 2.4.28: When the data in a 2-bit group is 11, according to the second rule in the 4D constellation mapping, the 4D-constellation point vector of the data 010 in the corresponding binary sequence of Date2 is (0, 0, 0.8164, 1); Step 2.4.29: When the data in a 2-bit group is 11, according to the second rule in the 4D constellation mapping, the 4D-constellation point vector of the data 110 in the corresponding binary sequence of Date2 is (0, 0, 0.8164, -1); Step 2.4.30: When the data in a 2-bit group is 11, according to the second rule in the 4D constellation mapping, the 4D-constellation point vector of the data 111 in the corresponding binary sequence of Date2 is (1.7321, 0, -0.8164, -1); Step 2.4.31: When the data in a 2-bit group is 11, according to the second rule in the 4D constellation mapping, the 4D-constellation point vector of the data 101 in the corresponding binary sequence of Date2 is (-0.5774, -1, -0.8164, -1); Step 2.4.32: When the data in a 2-bit group is 11, according to the second rule in the 4D constellation mapping, the 4D-constellation point vector of the data 100 in the corresponding binary sequence of Date2 is (-0.5774, 1, -0.8164, -1); The 1 in the fourth dimension of the 4D-constellation point vector represents one color, and the -1 in the fourth dimension of the 4D-constellation point vector represents another color.

7. The non-orthogonal encoding method based on color-coded four-dimensional constellation pairing mapping according to claim 1, characterized in that: The OCDM symbol calculation formula is as follows: Among them, S 4D Indicates OCDM symbols, G1, G2, G n , G M Represent the 1st, 2nd, nth, and Mth 4D-constellation point vectors respectively; Where, Among them, G x，n , G y，n , G z，n and G f，n The vectors representing the x, y, z and f dimensions of the n-th 4D-constellation point vector respectively.

8. The non-orthogonal encoding method based on color-coded four-dimensional constellation pairing mapping according to claim 1, characterized in that: The calculation formula of the time domain signal T is as follows: in, k1 and k2 are the k1 and k2 rows of the DFnT matrix, respectively. -1 represents the 4×4 inverse IFFT matrix, H M -1 Represents the M×M inverse IFFT matrix.

9. The non-orthogonal encoding method based on color-coded four-dimensional constellation pairing mapping according to claim 1, characterized in that: The calculation formula of the OCDM baseband signal is as follows: Wherein, s(n) is the OCDM baseband signal, T1”(t) represents the first channel signal sequence, T2”(t) represents the second channel signal sequence, P1 represents the high power ratio, P2 represents the low power ratio, and P1+P2=1; The calculation formula of 4D-NOMA signal is as follows: Among them, s DUC (n) is the 4D-NOMA signal, f is the frequency of the mixing signal, f s is the sampling frequency, s I (n) represents the real part of the OCDM signal, s Q (n) represents the imaginary part of the OCDM signal.

10. A transmitting end, characterized in that: The transmitting end is used to execute a non-orthogonal encoding method based on color-coded four-dimensional constellation pairing mapping as claimed in any one of claims 1 to 9.

Images