CN102075487B - Coding and modulation method, demodulation and decoding method and system based on multi-dimensional constellation mapping - Google Patents

Abstract

The invention relates to a multidimensional constellation mapping based coding and modulating method, demodulating and decoding method and system. The coding and modulating method comprises the following steps of: carrying out channel coding and bit interleaving on input information bits to obtain coded interleaved bits; carrying out K-dimensional pulse amplitude modulated constellation mapping on the coded and interleaved bits to obtain a constellation mapping symbol of a K-dimensional real-number vector, wherein K is a positive integer; carrying out constellation rotation on the constellation mapping symbol to obtain a multidimensional rotated constellation mapping symbol of the K-dimensional real-number vector; and carrying out dimension conversion and general real-number interleaving on the multidimensional rotated constellation mapping symbol to obtain a coded and modulated symbol, and outputting the coded and modulated symbol. The method and system in the invention can ensure that the performances of a coding and modulating system and a corresponding demodulating and decoding system approach the channel capacity at medium and low frequency spectrum efficiency under the AWGN (Added White Gaussian Noise) and fading channel conditions and meanwhile, the throughput of the system is taken into consideration.

Description

Coding and modulation method, demodulation and decoding method and system based on multi-dimensional constellation mapping

technical field

The invention relates to the field of digital information transmission, in particular to a coding and modulation method, demodulation and decoding method and system based on multidimensional constellation mapping. the

Background technique

The fundamental task of digital communication systems, especially wireless communication systems, is to provide high-speed, efficient and error-free transmission of digital information using limited bandwidth. In order to meet the transmission requirements of digital information on common analog channels, channel coding technology usually needs to be combined with digital modulation technology. Coding and modulation technology is an effective method and an important means to realize the fundamental task of the wireless communication system. The combination of channel coding and modulation constitutes a coded modulation system, which is a subsystem of the digital communication system transmitter and one of its core modules, and the corresponding coded modulation technology is also the core technology of the digital communication system. Corresponding to the coding and modulation system, the combination of demodulation and channel decoding constitutes the demodulation and decoding system at the receiving end of the digital communication system, and the corresponding demodulation and decoding technology is also the core technology of the digital communication system. the

Generally speaking, channel coding is designed and optimized for memoryless channels. In order to adapt to channel decoding at the receiving end and improve the diversity order of the coded modulation system, the most common method is to use interleaving technology to make the input demodulator and The information from the decoder exhibits an approximately memoryless property. the

The so-called modulation means transforming input data or signals to obtain signals suitable for channel transmission, including various analog modulation and digital modulation techniques. For a typical digital communication system, the digital modulation technology mainly includes constellation mapping technology and subsequent processing technology, such as multi-carrier modulation technology and shaping filtering technology. The so-called constellation mapping is to map the finite field "bit" sequence carrying digital information into a "symbol" sequence suitable for transmission. The value space of each symbol can be a one-dimensional real number space, a two-dimensional real number space (that is, a complex number space or a complex number plane), or a higher-dimensional real number space (such as a space corresponding to signal transmission of a multi-antenna MIMO system). Constellation mapping includes two elements, namely constellation diagram and constellation point mapping method. The constellation diagram represents a set of all values of the output symbols of the constellation map, wherein each point of the constellation diagram corresponds to a value of the output symbol. The constellation point mapping method represents the specific mapping relationship between the input bit (group) and the constellation point, or the specific mapping relationship between the constellation point and the bit (group). Usually, each constellation point corresponds to a bit or a bit group composed of multiple bits. . At present, the most common and practical complex space constellation diagrams mainly include QAM (Quadrature Amplitude Modulation, Quadrature Amplitude Modulation), PSK (Phase Shift Keying, Phase Shift Keying), and APSK (Amplitude-Phase Shift Keying, amplitude phase shift keying) ) modulation technology; the constellation diagram of real number space is mainly PAM (Pulse Amplitude Modulation, pulse amplitude modulation). In the decoding and demodulation system at the receiving end, what corresponds to constellation mapping is constellation demapping, referred to as demapping. Usually, the constellation demapping is based on a constellation diagram and a constellation point mapping manner, combined with channel state information to obtain bit soft information of one or more bits corresponding to a received symbol. the

A fundamental index to measure coding and modulation technology is: under the condition of given spectrum efficiency and error control target, the distance between the required signal-to-noise ratio threshold and the information theory circle. The spectral efficiency is usually represented by the effective information bits that can be transmitted in each dimension of the M-dimensional real number space of the constellation diagram. For example, for a traditional 64QAM system without channel coding, its spectral efficiency is 3 bits/symbol/dimension, where each constellation symbol It consists of two-dimensional real numbers and can carry 6 bits of information. The error control target is usually represented by bit error rate or code word error rate (also known as block error rate). The information theory community is usually expressed in terms of the minimum signal-to-noise ratio required to achieve error-free transmission. According to the basic knowledge of information theory, for a given coded modulation system and given channel conditions, the information theory boundary (assumed to be expressed in signal-to-noise ratio) is a monotonically increasing function of spectral efficiency, which is uniquely determined by spectral efficiency. the

The basic theory of coding and modulation technology is Shannon information theory, which is mainly point-to-point single-user information theory. When the transmission power is limited, the channel capacity can only be achieved when the output of the coded modulation system satisfies the white Gaussian distribution. At the same time, the channel coding theorem in information theory points out that as long as the transmission rate is smaller than the channel capacity, there must be a coded modulation system for error-free transmission. However, the basic theory only solves the existence of coding and modulation. How to construct a feasible coding and modulation system approaching the limit has been the goal that the field of communication has been striving for for decades. the

For typical poor transmission channels with limited power and bandwidth, such as transmission channels of broadband wireless mobile communication and terrestrial digital broadcasting systems, coded modulation technology is an important guarantee for transmission reliability and system spectral efficiency. Therefore, the latest broadband wireless mobile The coding and modulation technology adopted by the communication and terrestrial digital broadcasting system as an industry standard represents the highest level of the coding and modulation technology currently used in practice. The second-generation terrestrial digital television broadcasting standard in Europe (DVB-T2) adopts low density parity check (Low Density Parity Check, LDPC) coding technology, bit interleaving technology, and high-order QAM modulation technology (including constellation rotation technology and IQ interleaving technology) technology); the European second-generation satellite digital TV broadcasting standard (DVB-S2) adopts bit interleaving technology, LDPC coding technology, and high-order APSK modulation technology; the LTE V8.1 proposal organized by 3GPP adopts Turbo coding technology, bit interleaving technology technology, and high-order QAM modulation technology. the

In academia, after decades of development, coded modulation technology has made great progress. The most typical one is Trellis Coded Modulation (TCM) proposed by G.Ungerboeck. See the literature G.Ungerboeck."Channel coding with multilevel phase signals." IEEE Trans.Inform.Theory, no.28, pp55-67, 1982.), and Bit-Interleaved Coded Modulation (BICM) proposed by E.Zehavi, see E.Zehavi, "8PSK trellis codes for a Rayleigh channel," IEEE Trans. Commun., vol.40, no.5, pp.873-884, May 1992. By maximizing the Euclidean distance, TCM has excellent performance in AWGN channels, but it is not ideal in fading channels; BICM is just the opposite, it has a loss compared with TCM in AWGN channels, but has Not bad performance. The BICM system for iterative demapping and decoding at the receiving end, that is, the BICM-ID system (BICM with Iterative Demapping and Decoding, BICM-ID for short) was independently proposed by Xiaodong Li et al. and Ten Brink et al., see literature X.Li and J.A.Ritcey, "Bit-interleaved coded modulation with iterative decoding using softfeedback," Electronics Letters, vol.34, no.10, pp.942-943, May 1998. and S.T.Brink, J.Speidel, and R.-H.Yan, " Iterative demapping and decoding for multilevel modulation," in Globecom'98, 1998, pp.579-584. The BICM-ID system increases the Euclidean distance by feeding back the decoded output information as the prior information for demapping, thus in Under the AWGN channel, the bit error performance is as good as that of TCM. However, the traditional BICM-ID has a high error platform, because even if all the feedback bit information is correct, the bit error rate of the system is still determined by the characteristics of the outer code (for linear codes, it mainly depends on the codebook The minimum non-zero code weight and its number) and the Harmonic Euclidean distance during demapping are determined, while the minimum code distance of the traditional codeword is small and its corresponding number is very large. the

However, generally speaking, the BICM-ID system needs to adopt high-order constellation mapping to better transfer information through iterative demapping, so the BICM-ID system is usually convenient to provide higher spectral efficiency. In order to make the BICM-ID system meet the requirements of low spectral efficiency, one method is to use a low code rate outer code (such as a 1/4 code word) in the BICM-ID system, and another method is to use multi-dimensional Constellation. At the same time, the robustness of the traditional BICM-ID system is not enough, that is, it cannot be applied to a variety of channel transmission conditions. For example, the BICM-ID system with excellent performance in the AWGN channel does not perform well in the fading channel. Signal Space Diversity (SSD) technology was first proposed by J.Boutros (see J.Boutros and E.Biterbo, "Signal space diversity: a power-andbandwidth-efficient diversity technique for the Rayleigh fading channel," IEEE Trans .Inform.Theory, vol.44, no.4, pp.1453-1467, July 1998.), combined with appropriate constellation diagram rotation can effectively combat fading, but the optimal rotation matrix has always been an open problem. The basic operation of SSD technology is to interleave the coordinates of each dimension of the signal after the constellation rotation, and then recombine the signal with the required dimension and send it to the back-end module. Through coordinate interleaving (Coordinate Interleaving), SSD makes each dimension in the same symbol under the fading channel experience independent fading, and the combination of constellation diagram rotation can effectively improve the diversity order. the

Contents of the invention

The purpose of the present invention is to provide a coding and modulation method, demodulation and decoding method and system based on multi-dimensional constellation mapping. The method and system can make the coding and modulation system and its corresponding demodulation and decoding system under AWGN and fading channel conditions The performance of the method is close to the channel capacity under medium and low spectral efficiencies, while taking into account the throughput of the system, which can overcome the shortcomings of the existing technology. the

In order to achieve the above object, the present invention adopts the following technical solutions. the

A kind of code modulation and demodulation decoding method based on multi-dimensional constellation mapping provided by the present invention, wherein the code modulation method comprises steps:

S1. Perform channel coding and bit interleaving on the input information bits to obtain coded interleaved bits;

S2. Performing rotated K-dimensional pulse amplitude modulation constellation mapping on the coded interleaving bits, or performing K-dimensional pulse amplitude modulation constellation mapping and constellation rotation, to obtain multi-dimensional rotated constellation mapping symbols, wherein K is a positive integer;

S3. Perform dimension conversion and general real number interleaving on the multi-dimensional rotated constellation mapping symbols to obtain coded modulation symbols and output them;

Wherein the demodulation decoding method comprises steps:

S4. Use the phase information of the externally input channel state information to perform phase correction on the received signal;

S5. Perform dimension conversion and general real number deinterleaving on the phase-corrected signal to obtain a deinterleaved signal, and also perform general real number deinterleaving on the amplitude information of the externally input channel state information;

S6. If it is the first demapping, directly perform demapping of the multi-dimensional rotated constellation on the deinterleaved signal to obtain soft information after demapping, otherwise, use the external information output by the last channel decoding as prior information, Perform demapping of the multi-dimensional rotated constellation to obtain soft information after demapping;

S7. Perform deinterleaving and channel decoding on the demapped soft information;

S8. If the set number of iterations is reached or the channel decoding verification is successful, output the channel decoding result; otherwise, re-interleave the channel decoding result to obtain the external information output by the channel decoding, and return to step S6. the

Wherein, step S2 further includes:

S2.1 Carry out constellation rotation on the K-dimensional pulse amplitude modulation constellation point to obtain the rotated K-dimensional pulse amplitude modulation constellation point;

S2.2 Carry out the rotated K-dimensional pulse amplitude modulation constellation mapping on the coded interleaved bits, and obtain the multi-dimensional rotated constellation mapping symbols of the K-dimensional real number vector;

or include:

S2.1 performs K-dimensional pulse amplitude modulation constellation mapping on the coded interleaving bits to obtain constellation mapping symbols of K-dimensional real number vectors;

S2.2 Perform constellation rotation on the constellation mapping symbols to obtain multi-dimensional rotated constellation mapping symbols of K-dimensional real number vectors. the

Wherein, in step S2: when K=1, the constellation mapping is pulse amplitude modulation constellation mapping; when K=2, the constellation mapping is quadrature amplitude modulation constellation mapping; when K=3, the constellation The mapping is a three-dimensional pulse amplitude modulation constellation mapping; when K=4, the constellation mapping is a four-dimensional pulse amplitude modulation constellation mapping. the

Wherein, in step S2.2, the constellation rotation method is to use a full-rank matrix to perform matrix transformation on the K-dimensional real number vector. the

Wherein, the full-rank matrix is an orthogonal matrix. the

When K=2, the orthogonal matrix is $R=\left[\begin{array}{cc}a& b\\ -b& a\end{array}\right],$ in, $a=1/\sqrt{1+{\mathrm{\λ}}^2},$ $b=\mathrm{\λ}/\sqrt{1+{\mathrm{\λ}}^2},$ λ is a real number;

When K=3, the orthogonal matrix is $R=\left[\begin{array}{ccc}a& b& c\\ b& c& a\\ -c& -a& -b\end{array}\right],$ Among them, a=(1+λ)/(1+λ+λ ² ), b=(λ+λ ² )/(1+λ+λ ² ), c=-λ/(1+λ+λ ² ) , λ is a real number;

When K=4, the orthogonal matrix is $R=\left[\begin{array}{cc}{m}_1& -m_2\\ m_2& {\mathrm{<figure-callout\; id="1"\; label="m"\; filenames="H2009102377694E00031.png"\; state="\{\{state\}\}">m</figure-callout>}}_1\end{array}\right],$ in, ${\mathrm{<figure-callout\; id="1"\; label="m"\; filenames="H2009102377694E00031.png"\; state="\{\{state\}\}">m</figure-callout>}}_1=\left[\begin{array}{cc}a& b\\ -b& a\end{array}\right],$ ${\mathrm{<figure-callout\; id="2"\; label="m"\; filenames="H2009102377694E00031.png"\; state="\{\{state\}\}">m</figure-callout>}}_2=\left[\begin{array}{cc}c& d\\ -d& c\end{array}\right],$ and $a=\frac{1}{\sqrt{1+{\mathrm{\&gamma;}}^2}}\&Center\; Dot;\frac{1}{\sqrt{1+{\mathrm{\&lambda;}}^2}},$ $b=\frac{1}{\sqrt{1+{\mathrm{\&gamma;}}^2}}\&Center\; Dot;\frac{\mathrm{\&lambda;}}{\sqrt{1+{\mathrm{\&lambda;}}^2}},$ $c=\frac{\mathrm{\&gamma;}}{\sqrt{1+{\mathrm{\&gamma;}}^2}}\&CenterDot;\frac{1}{\sqrt{1+{\mathrm{\&lambda;}}^2}},$ $d=\frac{\mathrm{\&gamma;}}{\sqrt{1+{\mathrm{\&gamma;}}^2}}\&CenterDot;\frac{\mathrm{\&lambda;}}{\sqrt{1+{\mathrm{\&lambda;}}^2}},$ Both λ and γ are real numbers.

Wherein, step S3 further includes:

S31. Perform dimension conversion on the multi-dimensional rotated constellation mapping symbol to obtain a first one-dimensional real number symbol;

S32. Perform universal real number interleaving on the first one-dimensional real number symbol to obtain a second one-dimensional real number symbol;

S33. Perform dimension conversion on the second one-dimensional real number symbols to obtain coded modulation symbols, and output them. the

Wherein _, in step S3, _the dimension conversion converts the input K _{in- dimensional} real number vector into a K _out- dimensional real number vector. _in real number symbols recompose N _out K _out dimensional real number vectors, where N _in K _in =N _out K _out , K _in and K _out are positive integers.

The present invention also provides a coding modulation and demodulation decoding system based on multi-dimensional constellation mapping, wherein the coding modulation system includes:

Encoding and interleaving module, used to perform channel encoding and bit interleaving on input information bits to obtain encoded and interleaved bits;

The constellation mapping module is used to perform rotated K-dimensional pulse amplitude modulation constellation mapping on the coded interleaved bits, or perform K-dimensional pulse amplitude modulation constellation mapping and constellation rotation to obtain multi-dimensional rotated constellation mapping symbols, wherein K is positive integer;

A dimension conversion and interleaving module, used to perform dimension conversion and general real number interleaving on the multi-dimensional rotated constellation mapping symbols to obtain coded modulation symbols and output them;

The demodulation and decoding system includes:

The phase correction module is used to use the phase information of the externally input channel state information to perform phase correction on the received signal;

Dimensional inverse conversion and deinterleaving module, used to perform dimensional conversion and general real number deinterleaving on the phase corrected signal to obtain deinterleaved signals, and also perform general real number deinterleaving to the amplitude information of the externally input channel state information ;

The demapping module, if it is the first demapping, directly performs multi-dimensional rotated constellation demapping on the deinterleaved signal to obtain soft information after demapping, otherwise, uses the extrinsic information output by the last channel decoding as prior information , carry out the demapping of the multi-dimensional rotated constellation, and obtain the soft information after demapping;

Deinterleaving and decoding module, used to perform deinterleaving and channel decoding on the demapped soft information to obtain channel decoding results;

The control module outputs the channel decoding result if the set number of iterations is reached or the channel decoding verification is successful; otherwise, the external information output by the channel decoding is re-interleaved as prior information and fed back to the demapping module. the

The method and system of the present invention greatly improve the diversity order under fading channels by using the constellation rotation technology of the multi-dimensional pulse amplitude modulation constellation diagram combined with the general real number interleaving technology of dimension conversion; combined with the demodulation and decoding method at the receiving end, it makes The BICM-ID system approaches the channel capacity under various channel conditions when the spectral efficiency is low or medium. the

Description of drawings

Fig. 1 is a flow chart of a coding and modulation method based on multidimensional constellation mapping according to an embodiment of the present invention;

Fig. 2 is a flow chart of a demodulation and decoding method based on multi-dimensional constellation mapping according to an embodiment of the present invention;

Fig. 3 is the constellation diagram according to the 3D-2PAM coding modulation of an embodiment of the present invention;

Fig. 4 is the mutual information under the independent Rayleigh fading channel and different λ values of the 3D-2PAM coded modulation system according to an embodiment of the present invention;

Fig. 5 is the mutual information under independent Rayleigh fading channel of the coding modulation system based on optimal transformation matrix according to an embodiment of the present invention;

Fig. 6 is the block diagram of the BICM-ID transmitting end coded modulation system adopting the multi-dimensional constellation diagram of embodiment 1;

Fig. 7 is the block diagram of the demodulation and decoding system of the BICM-ID receiving end adopting the multi-dimensional constellation diagram of embodiment 1;

Figure 8(a)-Figure 8(b) is a block diagram of encoding and modulation at the transmitting end of the BICM-ID system using cascaded channel encoding in Embodiment 2;

Fig. 9 is the bit error performance of the coding and modulation system based on the optimal transformation matrix according to an embodiment of the present invention;

Fig. 10(a) - Fig. 10(b) is a block diagram of coding and modulation at the transmitting end of the BICM-ID system using concatenated channel coding in Embodiment 3. the

Detailed ways

The encoding and modulation method, demodulation and decoding method and system based on multi-dimensional constellation mapping proposed by the present invention are described as follows in conjunction with the accompanying drawings and embodiments. the

As shown in Figure 1, a coding and modulation method based on multidimensional constellation mapping according to an embodiment of the present invention includes steps:

S1. Perform channel coding and bit interleaving on the input information bits to obtain coded interleaved bits;

Among them, the channel coding methods include parity check coding, CRC coding, BCH block coding, RS block coding, convolutional code, punctured convolutional code, Turbo coding, LDPC coding, serial concatenated channel coding, parallel concatenated channel coding , or a combination of the above encoding methods. the

S2. Carry out rotated K-dimensional pulse amplitude modulation constellation mapping on coded interleaving bits, or perform K-dimensional pulse amplitude modulation constellation mapping and constellation rotation to obtain multi-dimensional rotated constellation mapping symbols, wherein K is a positive integer;

Wherein, step S2 further includes:

S2.1 Carry out constellation rotation on the K-dimensional pulse amplitude modulation constellation point to obtain the rotated K-dimensional pulse amplitude modulation constellation point;

S2.2 Carry out the rotated K-dimensional pulse amplitude modulation constellation mapping on the encoded interleaved bits, and obtain the multi-dimensional rotated constellation mapping symbol of the K-dimensional real number vector;

or include:

S2.1 Carry out K-dimensional pulse amplitude modulation constellation mapping on coded interleaving bits, and obtain the constellation mapping symbols of K-dimensional real number vectors;

S2.2 Perform constellation rotation on the constellation mapping symbols to obtain multi-dimensional rotated constellation mapping symbols of K-dimensional real number vectors. the

Multidimensional pulse amplitude modulation constellation mapping (denoted as KD-PAM, where K represents the dimension) is a constellation mapping that regularly maps bits or groups of bits to multidimensional real number space points, each of which is a traditional pulse amplitude modulation constellation mapping (i.e. PAM). When the dimension K=1, KD-PAM is traditional PAM; when K=2, KD-PAM is traditional QAM; when K=3, record the 3D-PAM constellation with n constellation points in each dimension The figure is 3D-nPAM; the size of the constellation diagram set (ie, the number of constellation points) in the following description is represented by the letter M, usually M=n ^K . A simple and effective way to construct a multi-dimensional constellation diagram is: directly expand the one-dimensional constellation diagram to K-dimensional (K>1), and then obtain a K-dimensional pulse amplitude modulation constellation diagram (KD-PAM for short), where K=2 The K-dimensional pulse amplitude modulation constellation diagram (2D-PAM), that is, the QAM constellation diagram, can be obtained. Combined with SSD technology, the multi-dimensional constellation obtained by extending the one-dimensional constellation is usually rotated by constellation rotation (equivalent to constellation point rotation, referred to as constellation rotation), which can improve the performance of the BICM-ID system in fading channels.

The number m of bits included in the bit group used for constellation mapping is determined by the number of constellation points M, and for equal-probability constellation mapping, m=log ₂ (M). For the special case of M=2, m=1 is obtained, that is, the bit group contains only one bit. Each constellation point in the K-dimensional real number space is a K-dimensional real number vector (that is, a K-dimensional real number symbol) composed of K real numbers, represented by x=[x ₁ x ₂ …x _K ], where x _i (1≤i≤K ) is a real number.

S3. Perform constellation rotation on the constellation mapping symbols obtained in step S2 to obtain multi-dimensional rotated constellation mapping symbols of K-dimensional real number vectors;

The method of constellation rotation is to use the transformation matrix (that is, the constellation rotation matrix) R to perform matrix transformation on the K-dimensional real number vector α to obtain a new K-dimensional real number vector β, namely

β=αR,

Where α=[α ₁ α ₂ …α _k ] is the K-dimensional real number vector before constellation rotation, and β=[β ₁ β ₂ …β _k ] is the K-dimensional real number vector after constellation rotation. Each dimension of the vector after constellation rotation, ie β _i , is obtained by linear combination of the K-dimensional components of vector α before constellation rotation, so constellation rotation can effectively improve the diversity order of the entire system. The transformation matrix R is a full-rank matrix, and in order to ensure the consistency of the average energy and spatial structure characteristics of the symbols before and after constellation rotation, the transformation matrix R is preferably an orthogonal matrix. The intersection vector serves as K rows or K columns of the transformation matrix R. Not performing constellation rotation is a special case of constellation rotation, and at this time, the transformation matrix is the identity matrix.

When K=2, the orthogonal matrix is preferably $R=\left[\begin{array}{cc}a& b\\ -b& a\end{array}\right]$

in, $a=1/\sqrt{1+{\mathrm{\&lambda;}}^2},$ $b=\mathrm{\&lambda;}/\sqrt{1+{\mathrm{\&lambda;}}^2},$ λ is a real number;

When K=3, the orthogonal matrix is preferably $R=\left[\begin{array}{ccc}a& b& c\\ b& c& a\\ -c& -a& -b\end{array}\right]$

Among them, a=(1+λ)/(1+λ+λ ² ), b=(λ+λ ² )/(1+λ+λ ² ), c=-λ/(1+λ+λ ² ) , λ is a real number;

When K=4, the orthogonal matrix is preferably $R=\left[\begin{array}{cc}{m}_1& -m_2\\ m_2& {\mathrm{<figure-callout\; id="1"\; label="m"\; filenames="H2009102377694E00031.png"\; state="\{\{state\}\}">m</figure-callout>}}_1\end{array}\right]$

in, ${\mathrm{<figure-callout\; id="1"\; label="m"\; filenames="H2009102377694E00031.png"\; state="\{\{state\}\}">m</figure-callout>}}_1=\left[\begin{array}{cc}a& b\\ -b& a\end{array}\right],$ ${\mathrm{<figure-callout\; id="2"\; label="m"\; filenames="H2009102377694E00031.png"\; state="\{\{state\}\}">m</figure-callout>}}_2=\left[\begin{array}{cc}c& d\\ -d& c\end{array}\right],$ and $a=\frac{1}{\sqrt{1+{\mathrm{\&gamma;}}^2}}\&CenterDot;\frac{1}{\sqrt{1+{\mathrm{\&lambda;}}^2}},$ $b=\frac{1}{\sqrt{1+{\mathrm{\&gamma;}}^2}}\&CenterDot;\frac{\mathrm{\&lambda;}}{\sqrt{1+{\mathrm{\&lambda;}}^2}},$ $c=\frac{\mathrm{\&gamma;}}{\sqrt{1+{\mathrm{\&gamma;}}^2}}\&CenterDot;\frac{1}{\sqrt{1+{\mathrm{\&lambda;}}^2}},$ $d=\frac{\mathrm{\&gamma;}}{\sqrt{1+{\mathrm{\&gamma;}}^2}}\&Center\; Dot;\frac{\mathrm{\&lambda;}}{\sqrt{1+{\mathrm{\&lambda;}}^2}},$ Both λ and γ are real numbers.

S3. Perform dimension conversion and general real number interleaving on the multi-dimensional rotated constellation mapping symbols obtained in step S2 to obtain coded modulation symbols and output them. the

Dimension conversion transforms the input K _in- dimensional real number vector into a K _out- dimensional real number vector. The method is to recompose all N _in K _in real number symbols on each dimension of the N _in K _in- dimensional real number vectors into N _out A K _out dimensional real number vector, where N _in K _in =N _out K _out , K _in and K _out are positive integers.

Define the spectral efficiency r as the average number of information bits transmitted per symbol per dimension, and the unit is "bits per symbol per dimension (bits/sym/dim)". For channel coding with code rate rate and K-dimensional equal-probability constellation mapping of M points, the spectral efficiency is

r=rate*m/K (bits/sym/dim)

In practice, a complex signal is usually transmitted each time, that is, a two-dimensional real signal. Therefore, the spectral efficiency of each dimension is r, which means that the number of information bits carried by each transmission is 2r, that is, 2r bits/channel use, which usually corresponds to the coded modulation system. The spectral efficiency is 2r bits/s/Hz. For different spectrum efficiency requirements, M=2 ^m constellation points are usually selected, where m is a positive integer.

Wherein, step S1 may further include:

S11. Perform first component code encoding or first component code group encoding on the input information bits to obtain the first encoded bits;

S12. Perform bit interleaving on the input information bits, and then encode the second component code or the second component code group to obtain the second coded bits;

S13. Combine the first coded bits and the second coded bits to obtain coded interleaved bits. the

Step S1 can further include:

S11'. Encoding the first component code or the first component code group on the input information bits to obtain the first coded bits;

S12'. Perform bit interleaving on the first coded bits to obtain interleaved bits;

S13'. Encoding the interleaved bits with a second component code or a second component code group to obtain coded interleaved bits. the

In addition, step S3 further includes:

S31. Perform dimension conversion on the multi-dimensional rotated constellation mapping symbol to obtain the first one-dimensional real number symbol;

S32. Perform universal real number interleaving on the first one-dimensional real number symbol to obtain the second one-dimensional real number symbol;

S32. Perform dimension conversion on the second one-dimensional real number symbol to obtain and output the coded modulation symbol. the

As shown in Figure 2, the demodulation and decoding method corresponding to the coding and modulation method based on multi-dimensional constellation mapping according to an embodiment of the present invention includes steps:

S4. Use the phase information of the externally input channel state information to perform phase correction on the received signal;

S5. Perform dimension conversion and general real number deinterleaving on the phase-corrected signal to obtain a deinterleaved signal, and perform general real number deinterleaving after the amplitude information of the externally input channel state information, so as to facilitate subsequent constellation demapping;

S6. If it is the first demapping, directly perform multi-dimensional rotated constellation demapping on the deinterleaved signal to obtain soft information after demapping; otherwise, use the external information output by the last channel decoding as prior information to perform multidimensional demapping Demapping of rotating constellations to obtain soft information after demapping;

S7. Deinterleave and channel decode the soft information after demapping;

S8. If the set number of iterations is reached or the channel decoding verification is successful, output the channel decoding result; otherwise, re-interleave the channel decoding result to obtain the external information output by the channel decoding, and return to step S6. the

The present invention also provides a coding and modulation system based on multi-dimensional constellation mapping corresponding to the above coding and modulation method. The system includes: a coding and interleaving module, which is used to perform channel coding and bit interleaving on input information bits to obtain coding and interleaving bits; constellation mapping A module for performing rotated K-dimensional pulse amplitude modulation constellation mapping on the coded interleaving bits, or performing K-dimensional pulse amplitude modulation constellation mapping and constellation rotation to obtain multi-dimensional rotated constellation mapping symbols, wherein K is a positive integer; The dimension conversion and interleaving module is used to perform dimension conversion and general real number interleaving on the multi-dimensional rotated constellation mapping symbols to obtain coded modulation symbols and output them. the

Wherein, the constellation mapping module may further include: a constellation rotation unit for performing constellation rotation on the K-dimensional pulse amplitude modulation constellation points to obtain the rotated K-dimensional pulse amplitude modulation constellation points; a constellation mapping unit for performing constellation rotation on the coded bits The rotated K-dimensional pulse amplitude modulation constellation map obtains the multidimensional rotated constellation map symbol of the K-dimensional real number vector;

Or include: a constellation mapping unit, which is used to perform K-dimensional pulse amplitude modulation constellation mapping on coded bits, to obtain constellation mapping symbols of K-dimensional real number vectors; a constellation rotation unit, used to perform constellation rotation on constellation mapping symbols, to obtain K-dimensional real number vectors multidimensional rotated constellation map symbol. the

The dimension conversion and interleaving module may further include: a first dimension conversion unit for performing dimension conversion on the constellation rotation symbols to obtain a first one-dimensional real number symbol; a general real number interleaving unit for converting the first one-dimensional real number symbol Perform universal real number interleaving to obtain a second one-dimensional real number symbol. Obviously, its input and output are both one-dimensional real number symbols; the second dimension conversion unit is used to perform dimension conversion on the second one-dimensional real number symbol to obtain a coded Modulation symbol, and output. Among them, the dimension conversion converts the input K _in- dimensional real number symbol into the output K _out- dimensional real number symbol, both K _in and K _out are positive integers, and their values are determined by external control signals.

The present invention also provides a demodulation and decoding system based on multi-dimensional constellation mapping corresponding to the above-mentioned demodulation and decoding method. Phase correction; dimension inverse conversion and deinterleaving module, used to perform dimension conversion and general real number deinterleaving on the phase corrected signal to obtain the deinterleaved signal, and also perform general real number solution to the amplitude information of the externally input channel state information Interleaving; the demapping module, if it is the first demapping, directly performs multi-dimensional rotated constellation demapping on the deinterleaved signal to obtain the soft information after demapping; otherwise, use the external information output by the last channel decoding as the first Demapping the multi-dimensional rotated constellation to obtain the demapped soft information; the deinterleaving and decoding module is used to deinterleave and channel decode the demapped soft information to obtain the channel decoding result; the control module, if it reaches the set If the number of iterations or the channel decoding result is correct, the channel decoding result is output; otherwise, the external information output by the channel decoding is re-interleaved, and fed back to the demapping module as prior information. the

In addition, in the present invention, the maximum mutual information criterion is used to select the optimal transformation matrix: assuming that the signal undergoes flat fading, after dimension transformation and general real number interleaving, the receiving end demodulates the input signal constellation signal of the demapping module in the decoding system It can be modeled as Y=H X+N, where X represents the signal output of the multi-dimensional rotated constellation map, H represents the channel gain of each dimension of the constellation symbol, N represents multi-dimensional noise, represents element-wise multiplication, and Y represents the received multidimensional signal. Under the constraints of the rotated multi-dimensional constellation diagram, and the receiver knows the CSI (Channel State Information, channel state information), the mutual information can be calculated as:

$\mathrm{<span\; class="notranslate">\; I</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; ;</span>\mathrm{<span\; class="notranslate">\; Y</span>}<span\; class="notranslate">\; |</span>\mathrm{<span\; class="notranslate">\; h</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="log"\; filenames="H2009102377694E00031.png"\; state="\{\{state\}\}">log</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; |</span>\mathrm{<span\; class="notranslate">\; \&chi;</span>}<span\; class="notranslate">\; |</span><span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; the\; y</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; h</span>}}<span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; log</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}\frac{{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}_{\stackrel{<span\; class="notranslate">\; ~</span>}{\mathrm{<span\; class="notranslate">\; x</span>}}<span\; class="notranslate">\; \&Element;</span>\mathrm{<span\; class="notranslate">\; \&chi;</span>}}\mathrm{<span\; class="notranslate">\; p</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; the\; y</span>}<span\; class="notranslate">\; |</span>\stackrel{<span\; class="notranslate">\; ~</span>}{\mathrm{<span\; class="notranslate">\; x</span>}}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; h</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; p</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; the\; y</span>}<span\; class="notranslate">\; |</span>\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; h</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

Wherein, χ represents the rotated constellation point set, |χ| represents the size of the constellation point set, for example, the 3D-2PAM constellation diagram contains 8 points, as shown in Figure 3, then the size of the 3D-2PAM constellation point set is 8. For the same constellation mapping, different constellation rotation matrices get different χ, thus affecting the mutual information shown in the above formula. The criterion for selecting the optimal transformation matrix in the present invention is to maximize the above mutual information. the

For a two-dimensional constellation diagram, the orthogonal transformation matrix in the present invention has the following form:

$\mathrm{<span\; class="notranslate">\; R</span>}<span\; class="notranslate">\; =</span>\left[\begin{array}{cc}\mathrm{<span\; class="notranslate">\; a</span>}& \mathrm{<span\; class="notranslate">\; b</span>}\\ <span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; b</span>}& \mathrm{<span\; class="notranslate">\; a</span>}\end{array}\right]$

in, $a=1/\sqrt{1+{\mathrm{\&lambda;}}^2},$ $b=\mathrm{\&lambda;}/\sqrt{1+{\mathrm{\&lambda;}}^2},$ λ is a real number. For 2D-PAM signals, common code rates (code rate ≤ 3/4), and independent Rayleigh channels, λ=±1 is the optimal solution.

For the three-dimensional constellation diagram, the orthogonal transformation matrix in the present invention can be expressed as:

$\mathrm{<span\; class="notranslate">\; R</span>}<span\; class="notranslate">\; =</span>\left[\begin{array}{ccc}\mathrm{<span\; class="notranslate">\; a</span>}& \mathrm{<span\; class="notranslate">\; b</span>}& \mathrm{<span\; class="notranslate">\; c</span>}\\ \mathrm{<span\; class="notranslate">\; b</span>}& \mathrm{<span\; class="notranslate">\; c</span>}& \mathrm{<span\; class="notranslate">\; a</span>}\\ <span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; c</span>}& <span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; a</span>}& <span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; b</span>}\end{array}\right]$

Among them, a=(1+λ)/(1+λ+λ ² ), b=(λ+λ ² )/(1+λ+λ ² ), c=-λ/(1+λ+λ ² ) , λ is a real number. Different λ corresponds to different transformation matrices R, and for different channel conditions or different coding rates, the optimal transformation matrix (expressed as R ^* ) is different. In the present invention, it is considered that for independent Rayleigh fading channels, only common code rates (code rate ≤ 3/4) are considered, and 1/2 code rate is especially concerned. For 3D-2PAM, since it contains 8 different constellation points, each constellation symbol can carry 3 bits of information in the uncoded system. When using 1/2 code rate, the useful information bits that can be carried are 1.5 bits per symbol, etc. Effective at 0.5 bits per dimension. Therefore, if the Signal to Noise Ratio (SNR) is set to 1.5dB, then for 3D-2PAM and an independent Rayleigh fading channel, the mutual information shown in (1) is about 1.5 bits per symbol. In the case of a given constellation diagram, fading channel, and signal-to-noise ratio, the mutual information shown in (1) is a function of λ, which can be written as I(λ). According to the symmetry of the 3D-2PAM constellation diagram and the symmetry of fading in each dimension, it is not difficult to obtain I(1/λ)=I(λ), and I(-1-λ)=I(λ). The I(λ) values under different λ values are shown in Figure 3. It is not difficult to see from the figure that λ=1 or λ=-0.5 is the local optimal solution within the range of λ shown in the figure. According to the above properties, it can be judged that λ=1, -0.5 or -2 are all global optimal solutions. The above optimal solution is an optimal solution for other three-dimensional orthogonal constellation diagrams, such as 3D-4PAM, 3D-8PAM, etc. The same method can also be applied to other scenarios, such as other constellation diagrams, other channels, and other code rates.

For the four-dimensional constellation diagram, the orthogonal transformation matrix in the present invention has the following form:

$\mathrm{<span\; class="notranslate">\; R</span>}<span\; class="notranslate">\; =</span>\left[\begin{array}{cc}{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}& <span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}\\ {\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}& {\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="m"\; filenames="H2009102377694E00031.png"\; state="\{\{state\}\}">m</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}\end{array}\right]$

in, ${\mathrm{<figure-callout\; id="1"\; label="m"\; filenames="H2009102377694E00031.png"\; state="\{\{state\}\}">m</figure-callout>}}_1=\left[\begin{array}{cc}a& b\\ -b& a\end{array}\right],$ ${\mathrm{<figure-callout\; id="2"\; label="m"\; filenames="H2009102377694E00031.png"\; state="\{\{state\}\}">m</figure-callout>}}_2=\left[\begin{array}{cc}c& d\\ -d& c\end{array}\right],$ and $a=\frac{1}{\sqrt{1+{\mathrm{\&gamma;}}^2}}\&Center\; Dot;\frac{1}{\sqrt{1+{\mathrm{\&lambda;}}^2}},$ $b=\frac{1}{\sqrt{1+{\mathrm{\&gamma;}}^2}}\&Center\; Dot;\frac{\mathrm{\&lambda;}}{\sqrt{1+{\mathrm{\&lambda;}}^2}},$ $c=\frac{\mathrm{\&gamma;}}{\sqrt{1+{\mathrm{\&gamma;}}^2}}\&Center\; Dot;\frac{1}{\sqrt{1+{\mathrm{\&lambda;}}^2}},$ $d=\frac{\mathrm{\&gamma;}}{\sqrt{1+{\mathrm{\&gamma;}}^2}}\&Center\; Dot;\frac{\mathrm{\&lambda;}}{\sqrt{1+{\mathrm{\&lambda;}}^2}},$ Both λ and γ are real numbers.

Obviously, for a given channel condition, a given SNR and a given unrotated 4D constellation, the mutual information shown in (1) can be written as a function I(γ,λ) of γ and λ. For the 4D-nPAM constellation diagram, the following properties can also be obtained: I(γ,λ)=I(λ,γ), I(1/γ,λ)=I(-γ,λ)=I(γ,λ) And I(γ,1/λ)=I(γ,-λ)=I(γ,λ). In this way, when looking for the optimal transformation matrix, it is only necessary to set the value ranges of γ and λ in the triangular area 0≤γ≤1, 0≤λ≤γ. For 4D-2PAM, under the conditions of independent Rayleigh channel and 1/2 code rate, when λ=γ=1 is the optimal solution. The resulting R matrix is an elementary row-column transformation of the normalized Hadamard matrix. Therefore, the present invention proposes that for 4D-2PAM, independent Rayleigh channel and common code rate (≤3/4), the 4×4 Hadamard matrix and its elementary row-column transformation can be considered as the optimal transformation matrix. This optimal transformation matrix is valid for other four-dimensional orthogonal constellation diagrams such as 4D-4PAM and 4D-8PAM. the

In order to better reflect the gain that the optimal constellation rotation can bring in the Rayleigh fading channel, the present invention proposes and selects the optimal transformation matrix, and gives 2D-2PAM (QPSK)/3D-2PAM/4D The variation trend of the mutual information value shown in (1) with the signal-to-noise ratio under the -2PAM limit is shown in Figure 4. The figure lists the channel capacity of the Rayleigh channel under the known CSI condition of the demodulation and decoding system, and the mutual information value under the constraints of 2D-2PAM (ie QPSK)/3D-2PAM/4D-2PAM constellation diagram under the condition that the constellation diagram does not rotate as Reference; the three curves in the middle are the mutual information values obtained by selecting an appropriate transformation matrix under the constraints of the above three constellation diagrams. It can be seen from the figure that choosing the optimal transformation matrix brings obvious gains in fading channels, and the higher the dimension, the closer the mutual information is to the channel capacity of fading channels. the

Embodiment 1 - BICM-ID system adopting multi-dimensional constellation diagram

This embodiment proposes a BICM-ID system using a multi-dimensional constellation diagram according to an implementation manner of the present invention. In order to enable the BICM-ID system to provide performance close to Shannon’s limit in AWGN and fading channels at the same time under medium and low spectral efficiency, this embodiment proposes to use a multi-dimensional constellation diagram with constellation rotation in the BICM-ID coded modulation system, combined with SSD technology. the

As shown in Figure 6, it is a schematic diagram of the coded modulation system and method of the BICM-ID system transmitter:

S101. Perform channel coding and bit interleaving on the input information bits to obtain coded interleaving bits;

S102. Carry out constellation mapping of K-dimensional pulse amplitude modulation to coded interleaving bits, and obtain the constellation mapping symbol of K-dimensional real number vector, wherein K is a positive integer;

S103. Perform constellation rotation on the constellation mapping symbols to obtain multi-dimensional rotated constellation mapping symbols of K-dimensional real number vectors;

S104. Perform dimension conversion on the multi-dimensional rotated constellation mapping symbol to obtain the first one-dimensional real number symbol;

S105. Perform universal real number interleaving on the first one-dimensional real number symbol to obtain the second one-dimensional real number symbol;

S106. Perform dimension conversion on the second one-dimensional real number symbols to obtain coded modulation symbols and output them. the

Wherein, the channel coding in step S101 can be convolutional code, block code, LDPC code, Turbo code, serial concatenated channel coding, or parallel concatenated channel coding;

FIG. 6 is a block diagram of a coding and modulation system of a BICM-ID transmitting end that adopts a multidimensional constellation diagram for constellation mapping and combines SSD technology. After the information to be transmitted is channel coded and bit interleaved by the encoding and interleaving module, the multidimensional constellation mapping is performed in the constellation mapping module, and then the constellation rotation is performed in the constellation rotation module, followed by dimension conversion 1 so that the multidimensional real number signal is converted into a one-dimensional real number signal , and then carry out general real number interleaving, and the interleaved signal will undergo dimension conversion 2 to obtain a signal of the required dimension (usually a two-dimensional real number signal), and send it to the subsequent module of the transmitter. the

The coded modulation system is characterized in that:

1. The channel coding in step S101 includes but is not limited to Turbo codes, serial concatenated codes, parallel concatenated codes, LDPC codes, convolutional codes, etc.;

2. The bit interleaving in step S101 can be canceled under special circumstances, for example, the channel coding code length is long enough, or the channel coding is concatenated coding with internal bit interleaving;

3. The multi-dimensional constellation mapping in step S102 and the constellation rotation in step S103 can be combined into one, only need to complete the multi-dimensional constellation mapping for the rotated constellation (referred to as multi-dimensional rotated constellation mapping, the receiving end is correspondingly referred to as multi-dimensional rotated constellation demapping). the

Figure 7 is a block diagram of the demodulation and decoding system at the receiving end of the BICM-ID system using a high-dimensional constellation diagram combined with SSD technology. At the receiving end, usually the received signal is firstly corrected by the phase correction module in step S201 and then sent to the dimension conversion unit 2' of the dimension conversion module (corresponding to the dimension conversion 2 at the sending end) and converted into a Dimensional real number signal, then perform general real number deinterleaving in step S203 and complete dimension conversion 1' (corresponding to dimension conversion 1 at the sending end) in step S204 to restore the multidimensional signal, and the amplitude information of CSI is also deinterleaved and dimensioned After the number is converted, it is sent to the demapping module. With the assistance of CSI amplitude information, constellation demapping is performed on the deinterleaved multi-dimensional signal according to the rotated constellation in step S205-step S207, and subsequent operations are consistent with traditional BICM-ID receivers. the

The receiving end demodulation decoding system is characterized in that:

1. The received signal completes the phase correction in step S201 with the assistance of the phase information of the CSI. the

2. Only the magnitude information of the CSI is subjected to step S203 general real number deinterleaving and step S204 dimension conversion 1', and then sent to the demapping module to assist in completing multidimensional rotated constellation demapping. the

3. Constellation demapping in step S205 and channel decoding in step S206 form a loop through deinterleaving in step S206 and reinterleaving in step S208, and are performed iteratively. the

Example 2

In order to further demonstrate the performance advantages of the BICM-ID system proposed by the present invention using a multi-dimensional constellation diagram combined with an optimal transformation matrix, this embodiment provides a BICM-ID system using 3D-nPAM with various specific parameters, and Give the bit error performance of the system. the

The code modulation method of this system comprises steps:

S301. Perform channel coding and bit interleaving on the input bits to obtain coded interleaving bits;

The system uses cascaded channel coding techniques, including parallel cascading and serial cascading technologies. As shown in Fig. 8(a) and 8(b), respectively represent the coding and modulation block diagrams of the transmitting end of the BICM and BICM-ID systems using parallel concatenated and serial concatenated channel coding. Among them, a typical example of parallel concatenated channel coding is a parallel concatenated Turbo code with a convolutional code as a component code, and a typical example of a serial concatenated channel coding is a serial concatenated Turbo code with a convolutional code as a component code. The coding and modulation block diagram uses two interleaving units, including the interleaving unit inside the concatenated channel coding and the bit interleaving unit between the concatenated channel coding and constellation mapping, which increases the complexity of coding, modulation, demodulation and decoding. Under certain conditions Next, the second interleaving unit can be removed. The specific steps of channel coding and bit interleaving are as follows:

S301.a encodes the first component code on the information bits to obtain the first coded bits;

S301.b performs bit interleaving on the information bits and then encodes the second component code to obtain the second coded bits;

S301.c combines the first coded bit and the second coded bit to obtain coded bits;

Alternatively, the specific steps of the channel coding and bit interleaving are as follows:

S301.d encodes the information bits with the first component code to obtain the first coded bits;

S301.e performs bit interleaving on the first coded bits to obtain interleaved bits;

S301.f performs the second component code encoding on the interleaved bits to obtain the second encoded bits, and the second encoded bits are the encoded interleaved bits;

S302. Perform constellation mapping of three-dimensional pulse amplitude modulation on the coded bits to obtain constellation mapping symbols of three-dimensional real number vectors;

Multidimensional pulse amplitude modulation constellation mapping is a constellation mapping that regularly maps bits or groups of bits to points in multidimensional real space. When the dimension K=3, the K-dimensional real number space degenerates into a three-dimensional space, which is 3D-nPAM, where n represents the number of constellation points in each dimensional space, obviously the number of constellation points M=n ³ .

For different spectrum efficiency requirements, M=2 ^m constellation points are usually selected, where m is a positive integer.

S303. Perform constellation rotation on the constellation mapping symbols obtained in step S302 to obtain the constellation rotation symbols of the three-dimensional real number vector;

Among them, the constellation rotation performs matrix transformation on the input three-dimensional real number vector (that is, three-dimensional real number symbol), and obtains the output three-dimensional real number vector (that is, three-dimensional real number symbol), wherein the transformation matrix is preferably an orthogonal matrix; further, the transformation matrix can be selected as the unit matrix (i.e. without rotation), you can also choose the optimal transformation matrix described in Example 2:

$\mathrm{<span\; class="notranslate">\; R</span>}<span\; class="notranslate">\; =</span>\left[\begin{array}{ccc}\mathrm{<span\; class="notranslate">\; a</span>}& \mathrm{<span\; class="notranslate">\; b</span>}& \mathrm{<span\; class="notranslate">\; c</span>}\\ \mathrm{<span\; class="notranslate">\; b</span>}& \mathrm{<span\; class="notranslate">\; c</span>}& \mathrm{<span\; class="notranslate">\; a</span>}\\ <span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; c</span>}& <span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; a</span>}& <span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; b</span>}\end{array}\right]$

Where a=(1+λ)/(1+λ+λ ² ), b=(λ+λ ² )/(1+λ+λ ² ), c=-λ/(1+λ+λ ² ), λ is a real number, and preferably λ=1, -0.5 or -2;

S304. Perform dimension conversion and general real number interleaving on the constellation rotation symbols obtained in step S303 to obtain coded modulation symbols and output them. the

In order to interface with the three-dimensional real number vector output by constellation rotation, the first dimension conversion step is set; in order to interface with the two-dimensional real number vector output by the coded modulation system, a second dimension conversion step is set. Dimension conversion converts the input 3D real number vector into a 2D real number vector, and its operation is to recombine all the real number symbols (3N ₁ in total) on each dimension of N ₁ 3D real number vectors into N ₂ 2D real number vectors , wherein, 3N ₁ =2N ₂ , N ₁ and N ₂ are positive integers.

In order to demonstrate the performance of the system proposed by the present invention, a specific coding and modulation system using 3D-2PAM constellation is given in this embodiment, and its detailed parameters are given: including outer code, Doping code word, constellation mapping method, code long wait. In the case of a given number of iterations, the bit error performance is given in detail, as shown in Figure 9. The specific parameters of the system are as follows:

Outer code: [7,5] ₈ non-systematic convolutional code with code rate 1/2;

●Bit interleaving: pseudo-random interleaving;

●Doping code word: a 2-state system convolutional code with a code rate of 1, and the Doping rate is set to 100, that is, every 100th information bit is replaced by a check bit;

●Code length: 192,000 bits;

●Number of iterations: 100;

●Constellation rotation parameter: λ=1;

●Mapping method: Let the unrotated 3D-2PAM constellation set be {x ₀ =(-1,-1,-1), x ₁ =(-1,-1,+1), x ₂ =(-1, +1,-1),...,x ₇ =(+1,+1,+1)}, the mapping method is 0→x ₇ ,1→x ₁ ,2→x ₀ ,3→x ₆ ,4→x ₄ , 5→x ₂ , 6→x ₃ and 7→x ₅ .

Example 3

In order to further demonstrate the performance advantages of the BICM-ID system using the multi-dimensional constellation diagram combined with the optimal rotation matrix proposed by the present invention, this embodiment provides a BICM-ID system using 4D-nPAM with various specific parameters. the

The encoding and modulation method at the sending end of the system includes steps:

S401. Perform channel coding and bit interleaving on the input bits to obtain coded interleaving bits;

Figures 10(a) and 10(b) respectively show the two BICM-ID system transmitter coding and modulation block diagrams proposed in this embodiment, using component code groups with parallel features to replace traditional single component codes, among them, Figure 10 (a) shows the system block diagram using parallel concatenated channel coding, and Fig. 10(b) shows the system block diagram using serial concatenated channel coding. The specific steps of the channel coding and bit interleaving are as follows:

S401.a encodes the first component code or the first component code group on the information bits to obtain the first coded bits;

S401.b performs bit interleaving on the first coded bits to obtain interleaved bits;

S401.c encodes the second component code or the second component code group on the interleaved bits to obtain the second coded bits, and the second coded bits are coded interleaved bits;

Or, the specific steps of the channel coding and bit interleaving are as follows:

S401.d encodes the first component code or the first component code group on the information bits to obtain the first coded bits;

S401.e performs bit interleaving on the information bits and then encodes the second component code or the second component code group to obtain the second coded bits;

S401.f combines the first encoded bit and the second encoded bit to obtain an encoded interleaved bit;

Wherein, the component codes may be convolutional codes or block codes; the component code groups are composed of multiple component codes in parallel, and each component code of the component code groups may be convolutional codes or block codes. the

S402. Perform constellation mapping of four-dimensional pulse amplitude modulation on coded interleaving bits, and obtain constellation mapping symbols of four-dimensional real number vectors;

S403. Perform constellation rotation on the constellation mapping symbols to obtain the constellation rotation symbols of the four-dimensional real number vector;

Among them, the constellation rotation performs matrix transformation on the input four-dimensional real number vector (that is, the four-dimensional real number symbol) to obtain the output four-dimensional real number vector (that is, the four-dimensional real number symbol), wherein the transformation matrix is preferably an orthogonal matrix; further, the transformation matrix can be selected as the unit matrix (i.e. without rotation), you can also choose the optimal transformation matrix described in Example 2:

$\mathrm{<span\; class="notranslate">\; R</span>}<span\; class="notranslate">\; =</span>\left[\begin{array}{cc}{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}& <span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}\\ {\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}& {\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="m"\; filenames="H2009102377694E00031.png"\; state="\{\{state\}\}">m</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}\end{array}\right]$

in ${\mathrm{<figure-callout\; id="1"\; label="m"\; filenames="H2009102377694E00031.png"\; state="\{\{state\}\}">m</figure-callout>}}_1=\left[\begin{array}{cc}a& b\\ -b& a\end{array}\right],$ ${\mathrm{<figure-callout\; id="2"\; label="m"\; filenames="H2009102377694E00031.png"\; state="\{\{state\}\}">m</figure-callout>}}_2=\left[\begin{array}{cc}c& d\\ -d& c\end{array}\right],$ and $a=\frac{1}{\sqrt{1+{\mathrm{\&gamma;}}^2}}\&CenterDot;\frac{1}{\sqrt{1+{\mathrm{\&lambda;}}^2}},$ $b=\frac{1}{\sqrt{1+{\mathrm{\&gamma;}}^2}}\&Center\; Dot;\frac{\mathrm{\&lambda;}}{\sqrt{1+{\mathrm{\&lambda;}}^2}},$ $c=\frac{\mathrm{\&gamma;}}{\sqrt{1+{\mathrm{\&gamma;}}^2}}\&Center\; Dot;\frac{1}{\sqrt{1+{\mathrm{\&lambda;}}^2}},$ $d=\frac{\mathrm{\&gamma;}}{\sqrt{1+{\mathrm{\&gamma;}}^2}}\&Center\; Dot;\frac{\mathrm{\&lambda;}}{\sqrt{1+{\mathrm{\&lambda;}}^2}},$ Both γ and λ are real numbers, and preferably γ=λ=1.

S404. Perform dimension conversion and general real number interleaving on the constellation rotation symbols to obtain coded modulation symbols and output them. the

In order to interface with the four-dimensional real number vector output by the constellation rotation, the first dimension conversion step is set; in order to interface with the two-dimensional real number vector that the coded modulation system needs to output, the second dimension conversion step is set. Dimension conversion converts the input four-dimensional real number vector into a two-dimensional real number vector, and its operation is to recombine all real number symbols (4N ₁ in total) on each dimension of N ₁ four-dimensional real number vectors into N ₂ 2-dimensional real number vectors , wherein, 4N ₁ =2N ₂ , N ₁ and N ₂ are positive integers.

The above embodiments are only used to illustrate the present invention, but not to limit the present invention. Those of ordinary skill in the relevant technical field can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, all Equivalent technical solutions also belong to the category of the present invention, and the scope of patent protection of the present invention should be defined by the claims. the

Claims (9)

1. A coding modulation and demodulation decoding method based on multidimensional constellation mapping, wherein the coding modulation method comprises steps: S1. Perform channel coding and bit interleaving on the input information bits to obtain coded and interleaved bits; S2. Performing rotated K-dimensional pulse amplitude modulation constellation mapping on the coded interleaving bits, or performing K-dimensional pulse amplitude modulation constellation mapping and constellation rotation, to obtain multi-dimensional rotated constellation mapping symbols, wherein K is a positive integer; S3. Perform dimension conversion and general real number interleaving on the multi-dimensional rotated constellation mapping symbols to obtain coded modulation symbols and output them; Wherein the demodulation decoding method comprises steps: S4. Using the phase information of the externally input channel state information to perform phase correction on the received signal; S5. Perform dimension conversion and general real number deinterleaving on the phase-corrected signal to obtain a deinterleaved signal, and perform general real number deinterleaving on the amplitude information of the externally input channel state information; S6. If it is the first demapping, directly perform demapping of the multi-dimensional rotated constellation on the deinterleaved signal to obtain soft information after demapping, otherwise, use the external information output by the last channel decoding as prior information, Perform demapping of the multi-dimensional rotated constellation to obtain soft information after demapping; S7. Perform deinterleaving and channel decoding on the demapped soft information; S8. If the set number of iterations is reached or the channel decoding verification is successful, output the channel decoding result; otherwise, re-interleave the channel decoding result to obtain the external information output by the channel decoding, and return to step S6. 2. The coding, modulation, demodulation and decoding method based on multi-dimensional constellation mapping as claimed in claim 1, wherein step S2 further comprises: S2.1 Perform constellation rotation on the K-dimensional pulse amplitude modulation constellation point to obtain the rotated K-dimensional pulse amplitude modulation constellation point; S2.2 Perform rotated K-dimensional pulse amplitude modulation constellation mapping on the coded interleaving bits to obtain multi-dimensional rotated constellation mapping symbols of K-dimensional real number vectors; or include: S2.1 Perform K-dimensional pulse amplitude modulation constellation mapping on the coded interleaving bits to obtain constellation mapping symbols of K-dimensional real number vectors; S2.2 Perform constellation rotation on the constellation mapping symbols to obtain multi-dimensional rotated constellation mapping symbols of K-dimensional real number vectors. 3. The coding modulation and demodulation decoding method based on multi-dimensional constellation mapping as claimed in claim 2, characterized in that, in step S2: When K=1, the constellation mapping is a pulse amplitude modulation constellation mapping; When K=2, the constellation mapping is quadrature amplitude modulation constellation mapping; When K=3, the constellation mapping is a three-dimensional pulse amplitude modulation constellation mapping; When K=4, the constellation mapping is a four-dimensional pulse amplitude modulation constellation mapping. 4. The encoding modulation and demodulation decoding method based on multi-dimensional constellation mapping as claimed in claim 2, characterized in that, in step S2.2, the constellation rotation method is to use a full rank matrix for the K-dimensional real number vector Perform matrix transformations. 5. The coding, modulation, demodulation and decoding method based on multi-dimensional constellation mapping according to claim 4, wherein the full rank matrix is an orthogonal matrix. 6. The coding modulation and demodulation decoding method based on multi-dimensional constellation mapping according to any one of claims 3-5, characterized in that, When K=2, the orthogonal matrix is $R=\left[\begin{array}{cc}a& b\\ -b& a\end{array}\right],$ in, $a=1/\sqrt{1+{\mathrm{\&lambda;}}^2},$ $b=\mathrm{\&lambda;}/\sqrt{1+{\mathrm{\&lambda;}}^2},$ λ is a real number; When K=3, the orthogonal matrix is $R=\left[\begin{array}{ccc}a& b& c\\ b& c& a\\ -c& -a& -b\end{array}\right],$ Among them, a=(1+λ)/(1+λ+λ ² ), b=(λ+λ ² )/(1+λ+λ ² ), c=-λ/(1+λ+λ ² ) , λ is a real number; When K=4, the orthogonal matrix is $R=\left[\begin{array}{cc}{m}_1& -m_2\\ m_2& m_1\end{array}\right],$ in, $m_1=\left[\begin{array}{cc}a& b\\ -b& a\end{array}\right],$ $m_2=\left[\begin{array}{cc}c& d\\ -d& c\end{array}\right],$ and $a=\frac{1}{\sqrt{1+{\mathrm{\&gamma;}}^2}}\&Center\; Dot;\frac{1}{\sqrt{1+{\mathrm{\&lambda;}}^2}},$ $b=\frac{1}{\sqrt{1+{\mathrm{\&gamma;}}^2}}\&Center\; Dot;\frac{\mathrm{\&lambda;}}{\sqrt{1+{\mathrm{\&lambda;}}^2}},$ $c=\frac{\mathrm{\&gamma;}}{\sqrt{1+{\mathrm{\&gamma;}}^2}}\&CenterDot;\frac{1}{\sqrt{1+{\mathrm{\&lambda;}}^2}},$ $d=\frac{\mathrm{\&gamma;}}{\sqrt{1+{\mathrm{\&gamma;}}^2}}\&Center\; Dot;\frac{\mathrm{\&lambda;}}{\sqrt{1+{\mathrm{\&lambda;}}^2}},$ Both λ and γ are real numbers. 7. The coding, modulation, demodulation and decoding method based on multi-dimensional constellation mapping as claimed in claim 1, wherein step S3 further comprises: S31. Perform dimension conversion on the multi-dimensional rotated constellation mapping symbol to obtain a first one-dimensional real number symbol; S32. Perform general real number interleaving on the first one-dimensional real number symbol to obtain a second one-dimensional real number symbol; S33. Perform dimension conversion on the second one-dimensional real number symbols to obtain coded modulation symbols, and output them. 8. The coding modulation and demodulation decoding method based on multi-dimensional constellation mapping as claimed in claim 2 or 7, it is characterized in that, in step S3, described dimension conversion converts the input K _in dimension real number vector into K _out dimension The real number vector, its method is, all total N _in K _in real number symbols on each dimension of N _in K _in dimension real number vectors are re-formed N _out K _out dimension real number vectors, wherein, N _in K _in =N _out K _out , K _in and K _out are positive integers. 9. A code modulation and demodulation decoding system based on multi-dimensional constellation mapping, wherein the code modulation system includes: An encoding and interleaving module, configured to perform channel encoding and bit interleaving on input information bits to obtain encoded and interleaved bits; The constellation mapping module is used to perform rotated K-dimensional pulse amplitude modulation constellation mapping on the coded interleaved bits, or perform K-dimensional pulse amplitude modulation constellation mapping and constellation rotation to obtain multi-dimensional rotated constellation mapping symbols, wherein K is positive integer; Dimension conversion and interleaving module, which is used to perform dimension conversion and general real number interleaving on the multi-dimensional rotated constellation mapping symbols to obtain coded modulation symbols and output them; The demodulation and decoding system includes: The phase correction module is used to use the phase information of the externally input channel state information to perform phase correction on the received signal; The dimensional inverse conversion and deinterleaving module is used to perform dimensional conversion and general real number deinterleaving on the phase-corrected signal to obtain a deinterleaved signal, and also perform general real number deinterleaving on the amplitude information of the externally input channel state information ; The demapping module, if it is the first demapping, directly performs multi-dimensional rotated constellation demapping on the deinterleaved signal to obtain soft information after demapping, otherwise, uses the extrinsic information output by the last channel decoding as prior information , perform demapping of the multi-dimensional rotated constellation, and obtain soft information after demapping; A deinterleaving and decoding module, configured to perform deinterleaving and channel decoding on the demapped soft information to obtain a channel decoding result; The control module outputs the channel decoding result if the set number of iterations is reached or the channel decoding verification is successful; otherwise, the external information output by the channel decoding is re-interleaved as prior information and fed back to the demapping module.

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