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

Abstract

The invention 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), is highly compatible with an OFDM (Orthogonal Frequency Division Multiplexing) system, and can perform modulation and demodulation by using the existing OFDM system. A method for pairing and mapping four-dimensional space primitives based on color coding according to different quadrants is innovatively explored, a fourth dimension is constructed on the basis of a three-dimensional constellation through color coding, and design of a four-dimensional constellation diagram with a high gain index is achieved. According to the method, the NOMA constellation diagram is used for receiving multiple power signals, then the multiple power signals are superposed through the non-orthogonal multiple access technology to achieve multi-channel access, the designed four-dimensional constellation design based on color coding improves the order of the NOMA constellation diagram from the angle of dimension extension, the problem that the receiving error rate is increased due to improvement of the order of the constellation diagram is solved, and the transmission performance of the system is improved.

Description

Technical Field

[0001] The 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 era of rapid digital development, information technology has penetrated into all aspects of society, and people's demand for high-speed, stable and intelligent network connections is increasing. With the rise of Internet of Things technology, various smart devices such as smart homes, smart cars and industrial sensors are constantly emerging. These devices require network connections to achieve data transmission and interaction. However, the existing access network is gradually unable to cope with such a large and diverse number of device connections. Passive optical network (PON) has become one of the core technologies of modern optical access networks due to its efficient bandwidth utilization, wide coverage and relatively low cost. From the early development of time division multiplexing (TDM-PON) to the present, PON technology has undergone many innovations and evolutions. In addition to traditional TDM-PON, wavelength division multiplexing (WDM-PON) and orthogonal frequency division multiplexing (OFDM-PON) have gradually become mainstream application solutions, further improving the capacity and transmission efficiency of the network. However, future development still requires PON systems to be combined with better modulation schemes to better meet the growing user needs and emerging application scenarios.

[0003] In recent years, orthogonal chirp multiplexing (OCDM) has gradually gained favor in optical fiber communication systems. As an emerging multi-carrier modulation technology, its complexity is similar to OFDM, but its performance is better. OCDM modulates the signal on a large number of orthogonal chirped subcarriers and transmits them in superposition. Due to its good pulse compression and spread spectrum capabilities, it can effectively cope with the frequency selective fading of the signal. Therefore, compared with OFDM, OCDM exhibits stronger anti-interference ability, its cyclic prefix (CP) is shorter, and it can maintain the same spectrum efficiency. The core structure of OCDM includes constellation mapping and inverse discrete Fresnel transform. Constellation mapping converts the input bit sequence into a complex signal, and the data difference is represented by the position of the constellation point. The design of the constellation diagram directly affects the power distribution of the signal, the information mapping dimension and the anti-interference ability. Increasing the information mapping dimension, that is, the improvement of the constellation diagram dimension, can significantly increase 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 the traditional OCDM to four-dimensional space, improves the utilization of the constellation space, and increases the minimum Euclidean distance (MED) of the 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 the system transmission performance, it still needs to ensure strict orthogonality between different chirped subcarriers. In order to meet the full coverage and large-scale access expected by 5G, non-orthogonal multiple access (NOMA) technology has gradually become a research hotspot. NOMA breaks the independence of traditional access methods by superimposing the signals of multiple users on the same resource block, achieving higher spectrum efficiency and accommodating more users. However, existing solutions are mostly based on low-dimensional constellation mapping, and still have problems such as insufficient anti-interference ability and low low-dimensional constellation capacity.

[0005] Therefore, how to optimize the design of the constellation structure and mapping rules for four-dimensional NOMA 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: In order to overcome the shortcomings of the prior art, the present invention provides a non-orthogonal coding 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 improve the 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 a binary sequence of M parallel 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 a binary sequence of M parallel Date2 through serial-to-parallel conversion, where M represents the number of subcarriers.

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

[0012] The binary sequence of parallel Date2 is subjected to four-dimensional constellation mapping 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] The OCDM symbol of Date1 and the OCDM symbol of Date2 are respectively subjected to two-dimensional inverse discrete Fresnel transform to obtain a time domain signal of Date1 and a time domain signal of Date2.

[0016] 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.

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

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

[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: According to the data in the binary sequence of each Date1, constellation mapping is performed according to 3D-QPSK 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, the binary sequence of parallel Date2 is subjected to four-dimensional constellation mapping to obtain the 4D-constellation point vector of Date2, specifically including:

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

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

[0031] Step 2.3: Pair a 2-bit group with the binary sequence of Date2, wherein 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] Among them, 1 in the fourth dimension of the 4D-constellation point vector represents one color, and -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] Among them, 1 in the fourth dimension of the 4D-constellation point vector represents one color, and -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 Respectively represent the 1st, 2nd, nth, and Mth 4D-constellation point vectors.

[0104] In the formula,

[0105] Among them, G x，n , G y，n , G z，n and G f，n Respectively represent the x, y, z and f-dimensional vectors of the n-th 4D-constellation point vector.

[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 k1th and k2th 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 proportion, P2 represents the low power proportion, 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, and 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, and the transmitting end is used 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 use the existing OFDM system for modulation and demodulation. The pairing mapping method of four-dimensional space primitives based on color coding is innovatively explored, and two four-dimensional space structures of 32 constellation points are 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 the method of pairing and mapping four-dimensional space primitives based on color coding according to different quadrants, constructs the fourth dimension on the basis of the three-dimensional constellation through color coding, and realizes the design of a four-dimensional constellation with a high gain index. Then, multi-power signals are superimposed through non-orthogonal multiple access technology to achieve multi-channel access. The designed four-dimensional constellation design based on color coding improves the order of the NOMA constellation from the perspective of expanding dimensions, solves the problem that the increase in the order of the constellation increases the receiving bit error rate, and improves the system transmission performance. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0121] Figure 2 Schematic diagram of the color-coded 4D-NOMA constellation design, 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 in the examples of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the protection scope of the present invention.

[0125] The present invention will be further described below in conjunction with specific embodiments.

[0126] Embodiment 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 a binary sequence of M parallel 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 a binary sequence of M parallel Date2 through serial-to-parallel conversion, where M represents the number of subcarriers.

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

[0131] The binary sequence of parallel Date2 is subjected to four-dimensional constellation mapping 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] The OCDM symbol of Date1 and the OCDM symbol of Date2 are respectively subjected to two-dimensional inverse discrete Fresnel transform to obtain a time domain signal of Date1 and a time domain signal of Date2.

[0135] 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.

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

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

[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: According to the data in the binary sequence of each Date1, constellation mapping is performed according to 3D-QPSK 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 binary sequence of the parallel Date2 is subjected to four-dimensional constellation mapping to obtain the 4D-constellation point vector of Date2, specifically including:

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

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

[0150] Step 2.3: Pair a 2-bit group with the binary sequence of Date2, wherein 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] Among them, 1 in the fourth dimension of the 4D-constellation point vector represents one color, and -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] Among them, 1 in the fourth dimension of the 4D-constellation point vector represents one color, and -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 Respectively represent the 1st, 2nd, nth, and Mth 4D-constellation point vectors.

[0223] In the formula,

[0224] Among them, G x，n , G y，n , G z，n and G f，n Respectively represent the x, y, z and f-dimensional vectors of the n-th 4D-constellation point vector.

[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 k1th and k2th 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 proportion, P2 represents the low power proportion, 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, and 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] Embodiment 2:

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

[0239] Embodiment 3:

[0240] This embodiment introduces the working principle of a non-orthogonal encoding method based on color-coded four-dimensional constellation pairing mapping. Figure 1 As shown in the figure, in the optical communication transmission system, two binary information sequences are converted from serial to parallel (S / P), 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 with the help of 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 the constellation points of the fourth dimension are represented by color coding to symbolize the density of the specific position of the signal in a certain three-dimensional space. The four-dimensional constellation design is completed by constructing 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 Two 4D-NOMA schemes in (a) and (b). The mapping rules and four-dimensional constellation coordinates of the two schemes at different powers are shown in Table 1. The high power ratio is P1, the low power ratio is P2 signal, P1+P2=1 and P1>P1, the signal corresponding to the high power ratio is Date1, and the signal corresponding to the low power ratio is Date2.

[0243] The signal corresponding to the high power ratio P1 is a QPSK (Quadrature PhaseShift Keying) constellation distribution in the three-dimensional space XOZ plane. A pairing mapping scheme is performed for the constellation points of the signal corresponding to the low power ratio P2, that is, different mapping rules are designed according to the constellation points of different quadrants of the high power signal. There are four mapping rules from case 1 to case 4 corresponding to the four quadrants of the signal corresponding to P1, and each mapping rule has a total of 8 constellation points. Therefore, the total constellation points are 4×8=32 constellation points, and the corresponding mapping rules are shown in Table 1. The data before the brackets in the table are the bits before mapping, and the data in the brackets are the position coordinates of the corresponding bits after mapping.

[0244] Because the four-dimensional construction method proposed in the present invention uses color coding to construct the fourth dimension based on the three-dimensional constellation, the low-power signal uses the standard three-dimensional space square distribution structure as the primitive to superimpose the 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 of Chen's constellation in four-dimensional space. In order to further utilize low-power point resources, 4D-NOMA2 is designed, as shown in Figure 2 As shown in (b). The signal corresponding to the high power ratio still uses the QPSK constellation distribution on the XOZ plane of the three-dimensional space. In order to maximize the minimum Euclidean distance (MED) of the constellation, the signal corresponding to the low power ratio uses a regular tetrahedron primitive structure, and the constellation distribution of the regular tetrahedron primitive is determined according to the quadrant distribution of the high power signal. Table 1 gives the mapping rules corresponding to the high power and low power ratio 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 needs to be transformed into a time domain signal by 2D-IDFnT (two-dimensional inverse discrete Fresnel transform). 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，nRepresents 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 4×4 and M×M inverse IFFT matrices respectively. It can be found that the generation and recovery of OCDM signals can be realized by 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 in the OCDM modulation process, the existence of the phase matrices Ψ1 and Ψ2 makes DFnT no longer have the conjugate symmetry property of discrete Fresnel transform (DFT), the 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 of 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 to the inside of the constellation, constructs a three-dimensional geometric structure with the minimum average energy of the constellation points, and then realizes the four-dimensional constellation design by superimposing the fourth dimension through color coding, improves the CFM of the constellation, and then generates a time domain chirp signal through a two-dimensional inverse discrete Fresnel transform (2D-IDFnT) of the mapped modulated signal, and then superimposes the signals of multiple users on the same resource block through the NOMA technology to achieve higher spectrum efficiency and accommodate more users. The 4D-NOMA signal enters the channel for transmission. At the receiver, the received superimposed signal is first decoded and restored into two signals using the successive interference cancellation (SIC) technology, and then the original information is restored by performing a 2D discrete Fresnel transform (2D-DFT) and demodulation.

[0271] Embodiment 4:

[0272] This embodiment introduces the verification process of the method of the present invention. Since the final NOMA constellation is formed by 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 calculate the optimal PDR of NOMA constellations of different dimensions through simulation on the premise that the constellation MED before superposition is fixed to 2, and 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, especially 4D-NOMA2 makes full use of the four-dimensional constellation space. Compared with the traditional 32-point square 3D-NOMA, the MED of the constellation point is increased by 11.8%, and the CFM is increased by 22.2%.

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

[0274]

[0275]

[0276] Where: Average energy E avg , minimum Euclidean distance (MED), and gain factor (CFM) are indicators to measure 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. 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 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 distribution 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 the four schemes, 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 achieved sensitivity gains of 1.0dB, 1.4dB, 0.9dB and 0.6dB respectively compared with their respective low-power signals. However, whether it is a high-power signal or a low-power signal, the required received optical power of 4D-NOMA is lower than that of 2D-NOMA and 3D-NOMA at the same bit error rate. Therefore, it can be predicted that the performance of 4D-NOMA is better than that of 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 the comparison of the bit error rate curves of various schemes under different optical powers. Among them, 4D-OFDM and 4D-OCDM use constellations 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, at 3.8×10 -3At a bit error rate of , compared with 3D-NOMA and 2D-NOMA, 4D-NOMA2 can obtain a sensitivity gain of 0.9dB and 1.3dB. And it can be noted that at high optical power, the performance of 4D-OCDM and 4D-NOMA is not much different. As the optical power decreases, the performance of 4D-OCDM is better than that of 4D-NOMA. This can be attributed to the error propagation effect of the SIC algorithm affecting the performance of the NOMA scheme. It can also be seen that the performance of 4D-OCDM and 4D-NOMA using 2D-IDFnT is better than that of 4D-OFDM using 2D-IFFT. Compared with 2D-IFFT, the linear frequency modulation signal generated by 2D-IDFnT has stronger anti-interference ability, which brings greater performance improvement and makes 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 principle 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 coding method based on color-coded four-dimensional constellation pairing mapping, characterized in that: Specifically include: In an optical communication transmission system, a binary information sequence Date1 is converted into a binary sequence of M parallel Date1 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 into a binary sequence of M parallel Date2 through serial-to-parallel conversion, 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; The M 4D-constellation point vectors of Date1 are combined into the OCDM symbol of Date1; Combining M 4D-constellation point vectors of Date2 into an OCDM symbol 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 binary sequence of the parallel Date1 is subjected to four-dimensional constellation mapping to obtain the 4D-constellation point vector of Date1, specifically including: 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: According to the data in the binary sequence of each Date1, constellation mapping is performed according to 3D-QPSK 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 binary sequence of parallel Date2 is subjected to four-dimensional constellation mapping to obtain the 4D-constellation point vector of Date2, specifically including: 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 four-dimensional constellation mapping, the 4D-constellation point vector of the data 001 in the binary sequence of the corresponding 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 four-dimensional constellation mapping, the 4D-constellation point vector of the data 011 in the binary sequence of the corresponding 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 four-dimensional constellation mapping, the 4D-constellation point vector of the data 010 in the binary sequence of the corresponding 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 four-dimensional constellation mapping, the 4D-constellation point vector of the data 111 in the binary sequence of the corresponding 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 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); 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); 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); 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); 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 binary sequence of the corresponding 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 four-dimensional constellation mapping, the 4D-constellation point vector of the data 010 in the binary sequence of the corresponding 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 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 2.4.14: 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 binary sequence of the corresponding 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 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); 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); 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 binary sequence of the corresponding 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 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); 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 binary sequence of the corresponding 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 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); 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); 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); 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); 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); 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 binary sequence of the corresponding 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 four-dimensional constellation mapping, the 4D-constellation point vector of the data 001 in the binary sequence of the corresponding 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 four-dimensional constellation mapping, the 4D-constellation point vector of the data 011 in the binary sequence of the corresponding 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 4D-constellation point vector of the data 010 in the corresponding binary sequence of Date2 is (-0.7071,-1,-0.7071,1); Step 2.4.29: 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); 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); 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); 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); Among them, 1 in the fourth dimension of the 4D-constellation point vector represents one color, and -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 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); 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); 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 binary sequence of the corresponding 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 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); 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 binary sequence of the corresponding 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 four-dimensional constellation mapping, the 4D-constellation point vector of the data 111 in the binary sequence of the corresponding 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 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); 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); 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 binary sequence of the corresponding 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 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); 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 binary sequence of the corresponding 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 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); 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 binary sequence of the corresponding 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 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); 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); 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); 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); 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 binary sequence of the corresponding 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 four-dimensional constellation mapping, the 4D-constellation point vector of the data 011 in the binary sequence of the corresponding 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 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); 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); 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); 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); 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); 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 binary sequence of the corresponding 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 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); 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 binary sequence of the corresponding 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 four-dimensional constellation mapping, the 4D-constellation point vector of the data 010 in the binary sequence of the corresponding 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 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); 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); 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); 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); Among them, 1 in the fourth dimension of the 4D-constellation point vector represents one color, and -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 Respectively represent the 1st, 2nd, nth, and Mth 4D-constellation point vectors; In the formula, Among them, G x，n , G y，n , G z，n and G f，n Respectively represent the x, y, z and f-dimensional vectors of the n-th 4D-constellation point vector.

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 k1th and k2th 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, and 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 in any one of claims 1 to 9.

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