WO2016082554A1

WO2016082554A1 - Superposition coding and decoding method and apparatus, transmitter, and receiver

Info

Publication number: WO2016082554A1
Application number: PCT/CN2015/083495
Authority: WO
Inventors: 袁志锋; 戴建强
Original assignee: 中兴通讯股份有限公司
Priority date: 2014-11-26
Filing date: 2015-07-07
Publication date: 2016-06-02
Also published as: CN105703877B; CN105703877A

Abstract

Disclosed are a superposition coding and decoding method and apparatus, a transmitter, and a receiver. The method comprises: modulating an information stream of a first type of user by using a binary phase shift keying (BPSK) modulation scheme to obtain a first modulated symbol, and modulating an information stream of a second type of user by using a second modulation scheme to obtain a second modulated symbol; allocating power to the first modulated symbol and the second modulated symbol; and superposing the first modulated symbol and the second modulated symbol after the power allocation, the constellation diagram of the superposed symbols being Gray mapped. The present invention resolves the problem in the related art that the performance of multiple users is not high when the multiple users are directly superposed, thereby achieving an effect of improving multi-user performance.

Description

Superposition coding, decoding method, device, transmitter and receiver

Technical field

The present invention relates to the field of communications, and in particular to a superposition encoding and decoding method, apparatus, transmitter and receiver.

Background technique

The multi-user information transmission technology can be divided into Orthogonal Multiple Access (OMA) and Non-Orthogonal Multiple Access (NOMA). In OMA technology, each user uses strictly parallel "sub-channels" to communicate. Relatively, the information of each user in the NOMA technology is transmitted on the "full channel", and the related works indicate that the NOMA method can achieve the OMA mode. The larger system capacity, FIG. 1 is a capacity comparison diagram of the NOMA mode and the OMA mode in the related art. As shown in FIG. 1 , the NOMA mode can preferentially increase the capacity of the cell edge user while substantially maintaining the high throughput of the center user. In order to increase the capacity of edge users, non-orthogonal access methods are usually selected. However, since the user information interferes with each other when demodulating in the NOMA mode, the receiving end usually performs Serial Interference Cancellation (SIC) separation information.

Multi-user information transmission has two cases of downlink transmission and uplink transmission. Non-orthogonal multi-user information Co-channel broadcast is also called multi-user information downlink transmission, or NOMA downlink broadcast, which means that the transmitter uploads the same time-frequency resources to the transmitter after superimposing the information of different users. Receivers. Among them, the process of superimposing signals of a plurality of users is also called "superimposition coding". The basic process of the NOMA downlink broadcast superposition coding is: the base station modulates the information flow according to the channel condition between the UE and the terminal UE according to the modulation mode of the matching channel; the base station allocates different powers to the two user signals (the edge user signal has a larger power) After direct superposition; the edge user at the receiving end directly demodulates, and the center user performs SIC demodulation.

Although the NOAM method can give priority to the capacity of the cell edge user, the channel environment between the edge user and the base station is poor, and the interference of the neighboring area is severe, so the edge user's spectrum efficiency is still low, or the data transmission rate is low. Taking two users as an example, according to the current superimposition coding scheme, the edge user and the central user can adopt QPSK mode or standard QAM mode modulation, and the two user symbols are directly superimposed after allocating a certain power, and the constellation diagram is not Gray mapped after superposition (adjacent symbols) Only one bit differs, and the constellation performance of the Gray mapping attribute is optimal. The performance of the center user SIC and the performance of the edge users are not high, and may not meet the increasingly high business requirements. The situation of more users is easy to promote.

Therefore, when multi-users directly superimpose in the related art, there is a problem that the multi-user performance is not high.

Summary of the invention

The invention provides a superposition coding and decoding method, a device, a transmitter and a receiver, so as to solve at least the problem that the multi-user performance is not high when the multi-user direct superposition in the related art.

According to an aspect of the present invention, a superposition coding method is provided, including: modulating a first type of user information by using a binary phase shift keying BPSK modulation method to obtain a first modulation symbol, and information flow to a second type of user. Modulating a second type of modulation to obtain a second modulation symbol; assigning power to the first modulation symbol and the second modulation symbol; performing the first modulation symbol and the second modulation symbol after power is allocated Superposition, wherein the constellation of the superimposed symbols is Gray mapped.

Optionally, the first type of user is a cell edge user in a first predetermined range of the cell, and the second type of cell is a cell center user in a second predetermined range of the cell.

Optionally, the BPSK modulation mode is a first type of binary phase shift keying BPSK modulation mode, or a second type of binary phase shift keying BPSK modulation mode, wherein the first type of BPSK modulation mode is: Bit 0 is modulated to a real number 1, and binary bit 1 is modulated to a real number -1; the second type of BPSK modulation is: modulating binary bit 0 to

Modulate binary bit 1 to

The second type of modulation method is one of the following: a four-phase phase shift keying QPSK modulation method, a quadrature amplitude modulation QAM modulation method, a 4-pulse amplitude modulation 4PAM modulation method, a rectangular constellation modulation method, and a diamond constellation modulation method.

Optionally, the BPSK modulation mode is a first type of binary phase shift keying BPSK modulation mode, and the second type of modulation mode is one of the following: QPSK modulation mode, QAM modulation mode, rectangular constellation modulation mode, diamond shape In the case of the constellation modulation method, the first modulation symbol and the second modulation symbol after power allocation are superimposed by one of the following formulas: C=Real(A)+Imag(A)·i+Sign (Real(A))·Real(B)+Imag(B)·i;C=Real(A)+Imag(A)·i-Sign(Real(A))·Real(B)+Imag(B) i; where C is the superimposed symbol, Real() is the real part of the modulation symbol, Imag() is the imaginary part of the modulation symbol, Sign() is the sign function, and Sign(Real(A) • Real(B)+Imag(B)·i indicates horizontal mirroring operation for symbol B, A is the first modulation symbol after power is allocated, and B is the second modulation symbol after power is allocated.

Optionally, the BPSK modulation mode is a second type of BPSK modulation mode, and the second type of modulation mode is one of the following: a QPSK modulation mode, a QAM modulation mode, a rectangular constellation modulation mode, and a diamond constellation modulation mode. In the case, the first modulation symbol and the second modulation symbol after power distribution are superimposed by one of the following formulas: C=Real(A)+Imag(A)·i+e ^iθ ·(Sign( Real(A))·Real(B)+Imag(B)·i);C=Real(A)+Imag(A)·i+e ^iθ ·(-Sign(Real(A))·Real(B) +Imag (B)·i); where C is the superimposed symbol, Real() is the real part of the modulation symbol, Imag() is the imaginary part of the modulation symbol, and Sign() is the sign function. Sign(Real(A))·Real(B)+Imag(B)·i denotes horizontal mirroring operation for symbol B, A is the first modulation symbol after power is allocated, and B is the second modulation symbol after power distribution, θ The angle of rotation after horizontal mirroring.

Optionally, when the BPSK modulation mode is the first type BPSK modulation mode, or the second type BPSK modulation mode, where the second type modulation mode is a 4PAM modulation mode, adopt one of the following formulas. And superimposing the first modulation symbol and the second modulation symbol after the power is allocated: C=Real(A)+Imag(A)·i+(Real(B)+Imag(B)·i); =Real(A)+Imag(A)·i+e ^iθ ·(Real(B)+Imag(B)·i); where C is the superimposed symbol and Real() is the real part of the modulation symbol Imag() is expressed as the imaginary part of the modulation symbol, Sign() is taken as the sign function, and Sign(Real(A))·Real(B)+Imag(B)·i means the horizontal mirroring operation on the symbol B, A is The first modulation symbol after power is allocated, B is the second modulation symbol after power distribution, and θ is the angle of rotation after horizontal mirroring.

According to another aspect of the present invention, a decoding method is provided, comprising: receiving a transmit signal transmitted by a transmitter, wherein the transmit signal is a binary phase shift keying of the information flow of the first type of user by the transmitter The BPSK modulation method performs modulation to obtain a first modulation symbol, and the second type of user information is modulated by the second type of modulation to obtain a second modulation symbol; and the first modulation symbol and the second modulation symbol are allocated power. After the power is allocated, the first modulation symbol and the second modulation symbol are superimposed, and the constellation of the superposed symbol is Gray mapped, wherein the second type of modulation includes the following One: four-phase phase shift keying QPSK modulation mode, quadrature amplitude modulation QAM modulation mode, rectangular constellation modulation mode, diamond constellation modulation mode, 4-pulse amplitude modulation 4PAM modulation mode; demodulation by demodulation method corresponding to modulation mode The information flow of the first type of users and/or the information flow of the second type of users.

According to an aspect of the present invention, a symbol superimposing apparatus is provided, comprising: a modulation module configured to modulate a first type of user's information stream by using a binary phase shift keying BPSK modulation method to obtain a first modulation symbol, and to The information stream of the class user is modulated by the second type of modulation to obtain the second modulation symbol; the allocation module is configured to allocate power for the first modulation symbol and the second modulation symbol; and the superimposing module is set to allocate power The first modulation symbol and the second modulation symbol are superimposed, wherein the constellation of the superposed symbols is Gray mapped.

Modulate binary bit 1 to

Optionally, the superimposing module includes: a first superimposing unit, configured to be in a first type of binary phase shift keying BPSK modulation mode in the BPSK modulation mode, and the second type of modulation mode is one of the following: QPSK modulation In the case of a mode, a QAM modulation mode, a rectangular constellation modulation mode, and a diamond constellation modulation mode, the first modulation symbol and the second modulation symbol after power distribution are superimposed by one of the following formulas: C= Real(A)+Imag(A)·i+Sign(Real(A))·Real(B)+Imag(B)·i;C=Real(A)+Imag(A)·i-Sign(Real( A))·Real(B)+Imag(B)·i; where C is the superimposed symbol, Real() is the real part of the modulation symbol, and Imag() is the imaginary part of the modulation symbol, Sign () is a symbol function, Sign(Real(A))·Real(B)+Imag(B)·i indicates horizontal mirroring operation for symbol B, A is the first modulation symbol after power is allocated, and B is after the power is allocated. The second modulation symbol.

Optionally, the superimposing module includes: a second superimposing unit, configured to be a second type of BPSK modulation mode in the BPSK modulation mode, and the second type of modulation mode is one of the following: QPSK modulation mode, QAM modulation mode In the case of a rectangular constellation modulation method or a diamond constellation modulation method, the first modulation symbol and the second modulation symbol after power distribution are superimposed by one of the following formulas: C=Real(A)+ Imag(A)·i+e ^iθ ·(Sign(Real(A))·Real(B)+Imag(B)·i); C=Real(A)+Imag(A)·i+e ^iθ ·( -Sign(Real(A))·Real(B)+Imag(B)·i); where C is the superimposed symbol, Real() is the real part of the modulation symbol, and Imag() is the pair modulation The symbol takes the imaginary part, Sign() takes the sign function, Sign(Real(A))·Real(B)+Imag(B)·i represents the horizontal mirroring operation for symbol B, and A is the first modulation symbol after the power is allocated. , B is the second modulation symbol after power is distributed, and θ is the angle of rotation after horizontal mirroring.

Optionally, the superimposing module includes: a third superimposing unit, configured to be in the BPSK modulation mode, the first type of BPSK modulation mode, or the second type of BPSK modulation mode, the second type of modulation mode In the case of the 4PAM modulation mode, the first modulation symbol and the second modulation symbol after power distribution are superimposed by one of the following formulas: C=Real(A)+Imag(A)·i+(Real (B) +Imag(B)·i); C=Real(A)+Imag(A)·i+e ^iθ ·(Real(B)+Imag(B)·i); where C is superimposed Symbol, Real() is represented as the real part of the modulation symbol, Imag() is represented as the imaginary part of the modulation symbol, Sign() is taken as the sign function, and Sign(Real(A))·Real(B)+Imag(B ·· represents the horizontal mirroring operation for symbol B, A is the first modulation symbol after power is allocated, B is the second modulation symbol after power distribution, and θ is the angle of rotation after horizontal mirroring.

According to another aspect of the present invention, a transmitter is provided, comprising the apparatus of any of the above.

According to another aspect of the present invention, a decoding apparatus is provided, comprising: a receiving module configured to receive a transmission signal transmitted by a transmitter, wherein the transmission signal is used by the transmitter for information flow of a first type of user The binary phase shift keyed BPSK modulation method performs modulation to obtain a first modulation symbol, and the information flow of the second type of user is modulated by using a second type of modulation method to obtain a second modulation symbol; and the first modulation symbol, the first After the second modulation symbol is allocated power, the first modulation symbol and the second modulation symbol after the power is allocated are superimposed, and the constellation of the superposed symbol is Gray mapped, wherein the second type The modulation method includes one of the following: four-phase phase shift keying QPSK modulation mode, quadrature amplitude modulation QAM modulation mode, rectangular constellation modulation mode, diamond constellation modulation mode, 4-pulse amplitude modulation 4PAM modulation mode; demodulation module, set to The information stream of the first type of user and/or the information stream of the second type of user are demodulated by using a demodulation method corresponding to the modulation mode.

According to still another aspect of the present invention, a receiver is provided, including the apparatus described above.

According to the embodiment of the present invention, the information stream of the first type of user is modulated by a binary phase shift keying BPSK modulation method to obtain a first modulation symbol, and the information flow of the second type of user is modulated by a second type modulation method. a second modulation symbol; a power is allocated to the first modulation symbol and the second modulation symbol; and the first modulation symbol and the second modulation symbol after the power is allocated are superposed, wherein the constellation of the superposed symbol The graph is Gray mapped, which solves the problem that the multi-user performance is not high when multi-user direct superposition in the related art, thereby achieving the effect of improving multi-user performance.

DRAWINGS

The drawings described herein are intended to provide a further understanding of the invention, and are intended to be a part of the invention. In the drawing:

1 is a capacity comparison diagram of a NOMA method and an OMA method in the related art;

2 is a flow chart of a superposition encoding method according to an embodiment of the present invention;

3 is a flow chart of a decoding method in accordance with an embodiment of the present invention;

4 is a block diagram showing the structure of a superimposition encoding apparatus according to an embodiment of the present invention;

5 is a block diagram 1 of a preferred structure of a superimposing module in a superimposition encoding apparatus according to an embodiment of the present invention;

6 is a block diagram 2 of a preferred structure of a superimposing module in a superimposition encoding apparatus according to an embodiment of the present invention;

7 is a block diagram 3 of a preferred structure of a superimposing module in a superimposition encoding apparatus according to an embodiment of the present invention;

FIG. 8 is a structural block diagram of a transmitter according to an embodiment of the present invention; FIG.

FIG. 9 is a structural block diagram of a decoding apparatus according to an embodiment of the present invention; FIG.

FIG. 10 is a structural block diagram of a receiver according to an embodiment of the present invention; FIG.

11 is a schematic diagram of a wireless broadcast communication system in accordance with a preferred embodiment of the present invention;

12 is a process diagram of a two-user information co-channel broadcast at a transmitting end according to a preferred embodiment of the present invention;

FIG. 13 is a schematic diagram of a process of a conventional superimposition coding method 1 according to Embodiment 1 of the present invention; FIG.

14 is a schematic diagram of a process of superimposing coding mode two superimposition coding according to Embodiment 1 of the present invention;

15 is a comparison diagram of an edge user performance of a superposition coding mode 2 and a conventional superposition coding mode according to a first embodiment of the present invention;

16 is a comparison diagram of a central user performance of a superposition coding mode 2 and a conventional superposition coding mode according to a first embodiment of the present invention;

17 is a schematic diagram of a process of superimposing coding mode 3 according to Embodiment 2 of the present invention;

18 is a schematic diagram of a process of superimposing coding mode 4 according to Embodiment 3 of the present invention;

19 is a comparison diagram of an edge user performance of a superposition coding method 4 and a conventional superposition coding method according to Embodiment 3 of the present invention;

20 is a comparison diagram of a central user performance of a superposition coding method 4 and a conventional superposition coding method according to Embodiment 3 of the present invention;

21 is a schematic diagram of a process of superimposing coding mode 5 according to Embodiment 4 of the present invention;

FIG. 22 is a schematic diagram of a process of superimposing coding mode six according to Embodiment 5 of the present invention; FIG.

23 is a comparison diagram of performance of an edge user of a superposition coding method 6 and a conventional superposition coding method according to Embodiment 5 of the present invention;

24 is a comparison diagram of a central user performance of a superposition coding method 6 and a conventional superposition coding method according to Embodiment 5 of the present invention;

25 is a schematic diagram of a process of superimposing coding mode VII according to Embodiment 6 of the present invention;

26 is a schematic diagram of a process of superimposing coding mode eight according to Embodiment 7 of the present invention;

27 is a comparison diagram of performance of an edge user of a superposition coding mode 8 and a conventional superposition coding mode according to Embodiment 7 of the present invention;

28 is a comparison diagram of a central user performance of a superposition coding mode 8 and a conventional superposition coding mode according to Embodiment 7 of the present invention;

29 is a schematic diagram of a process of superimposing coding mode nine according to an eighth embodiment of the present invention.

detailed description

The invention will be described in detail below with reference to the drawings in conjunction with the embodiments. It should be noted that the embodiments in the present application and the features in the embodiments may be combined with each other without conflict.

In this embodiment, a superposition coding method is provided. FIG. 2 is a flowchart of a superposition coding method according to an embodiment of the present invention. As shown in FIG. 2, the process includes the following steps:

Step S202: Modulating the information flow of the first type of users by using a binary phase shift keying BPSK modulation method to obtain a first modulation symbol, and modulating the information flow of the second type of user by using a second type of modulation manner to obtain a second modulation symbol;

Step S204, allocating power for the first modulation symbol and the second modulation symbol;

Step S206, superimposing the first modulation symbol and the second modulation symbol after the power is allocated, wherein the constellation of the superimposed symbol is Gray mapped.

Through the above steps, the information flow of the first type of users is modulated by a binary phase shift keying BPSK modulation method, the information flow of the second type of users is modulated by the second type of modulation, and the first modulation after power distribution is performed. The symbol and the second modulation symbol are superimposed, and the constellation diagram of the superimposed symbol is Gray-mapped, which solves the problem that the multi-user performance is not high when multi-user direct superposition in the related art, thereby achieving the improvement of multi-user performance. Effect.

The first type of user may be a cell edge user in a first predetermined range of the cell, and the second type of cell may be a cell center user in a second predetermined range of the cell.

The above BPSK modulation method can be variously combined as the first type of modulation method and the second type of modulation method, for example, the BPSK modulation mode is the first type of binary phase shift keying BPSK modulation mode, or the second type of binary phase shift keying The BPSK modulation method, wherein the first type of BPSK modulation method is: modulation of binary bit 0 into real number 1, modulation of binary bit 1 into real number -1; and second type of BPSK modulation mode: modulation of binary bit 0 into

Modulate binary bit 1 to

The second type of modulation method is one of the following: four-phase phase shift keying QPSK modulation mode, quadrature amplitude modulation QAM modulation mode, 4-pulse amplitude modulation 4PAM modulation mode, rectangular constellation modulation mode, and diamond constellation modulation mode.

Optionally, when the BPSK modulation mode and the second type modulation mode are differently combined, the manner of superposition of symbols obtained by the modulation may be different. For example, in the foregoing BPSK modulation mode, the first type of binary phase shift keying BPSK modulation mode is used. The second type of modulation is one of the following: in the case of QPSK modulation, QAM modulation, rectangular constellation modulation, and diamond constellation modulation, the first modulation symbol after power is allocated by one of the following formulas, The second modulation symbol is superimposed: C=Real(A)+Imag(A)·i+Sign(Real(A))·Real(B)+Imag(B)·i; C=Real(A)+Imag( A)·i-Sign(Real(A))·Real(B)+Imag(B)·i; where C is the superimposed symbol, Real() is the real part of the modulation symbol, and Imag() In order to take the imaginary part of the modulation symbol, Sign() takes the sign function, Sign(Real(A))·Real(B)+Imag(B)·i denotes the horizontal mirroring operation for symbol B, and A is the first after the power is allocated. a modulation symbol, B is a second modulation symbol after power is allocated; for example, in the BPSK modulation mode, the second type of BPSK modulation mode, and the second type of modulation mode is one of the following In the case of QPSK modulation method, QAM modulation method, rectangular constellation modulation method, and diamond constellation modulation method, the first modulation symbol and the second modulation symbol after power distribution are superimposed by one of the following formulas: C=Real( A) +Imag(A)·i+e ^iθ ·(Sign(Real(A))·Real(B)+Imag(B)·i); C=Real(A)+Imag(A)·i+e ^Iθ ·(-Sign(Real(A))·Real(B)+Imag(B)·i); where C is the superimposed symbol, Real() is the real part of the modulation symbol, and Imag() In order to take the imaginary part of the modulation symbol, Sign() takes the sign function, Sign(Real(A))·Real(B)+Imag(B)·i denotes the horizontal mirroring operation for symbol B, and A is the first after the power is allocated. a modulation symbol, B is a second modulation symbol after power distribution, and θ is an angle of rotation after horizontal mirroring; for example, a BPSK modulation method is a first type BPSK modulation method, or a second type BPSK modulation method, and a second type When the modulation method is the 4PAM modulation method, the first modulation symbol and the second modulation symbol after the power distribution are superimposed by one of the following formulas: C=Real(A)+Imag(A)·i+(Real(B) ) +Imag(B)·i);C=Real (A)+Imag(A)·i+e ^iθ ·(Real(B)+Imag(B)·i); where C is the superimposed symbol and Real() is the real part of the modulation symbol, Imag () is expressed as the imaginary part of the modulation symbol, Sign() is the sign function, Sign(Real(A))·Real(B)+Imag(B)·i is the horizontal mirroring operation for symbol B, and A is the distributed power. The first first modulation symbol, B is the second modulation symbol after power distribution, and θ is the angle of rotation after horizontal mirroring.

In this embodiment, a decoding method is also provided. FIG. 3 is a flowchart of a decoding method according to an embodiment of the present invention. As shown in FIG. 3, the process includes the following steps:

Step S302: Receive a transmit signal sent by the transmitter, where the transmit signal is that the transmitter modulates the information flow of the first type of user by using a binary phase shift keying BPSK modulation method to obtain a first modulation symbol, and information about the second type of user. The stream is modulated by the second type of modulation to obtain a second modulation symbol; and after the power is allocated to the first modulation symbol and the second modulation symbol; the first modulation symbol and the second modulation symbol after the power is allocated are superimposed, and The constellation of the superimposed symbols is Gray mapped, wherein the second type of modulation includes one of the following: four-phase phase shift keying QPSK modulation, quadrature amplitude modulation QAM modulation, rectangular constellation modulation, and diamond constellation Modulation method, 4-pulse amplitude modulation 4PAM modulation method;

Step S304, demodulating the information flow of the first type of user and/or the information flow of the second type of user by using a demodulation method corresponding to the modulation mode.

Through the above steps, the decoding corresponding to the above coding mode also effectively solves the problem that the multi-user performance is not high when the multi-user direct superposition in the related art, thereby achieving the effect of improving multi-user performance.

An apparatus for superimposing encoding and decoding is also provided in this embodiment, and the apparatus is used to implement the foregoing embodiments and preferred embodiments, and details are not described herein. As used below, the term "module" may implement a combination of software and/or hardware of a predetermined function. Although the apparatus described in the following embodiments is preferably implemented in software, hardware, or a combination of software and hardware, is also possible and contemplated.

4 is a block diagram showing the structure of a superimposition encoding apparatus according to an embodiment of the present invention. As shown in FIG. 4, the apparatus includes a modulation module 42, an allocation module 44, and a superimposing module 46, which will be described below.

The modulating module 42 is configured to modulate the information flow of the first type of users by using a binary phase shift keying BPSK modulation method to obtain a first modulation symbol, and modulate the information flow of the second type of user by using a second type of modulation mode to obtain a second modulation symbol. a modulation symbol; an allocation module 44, coupled to the modulation module 42 configured to allocate power for the first modulation symbol and the second modulation symbol; and a superposition module 46 coupled to the distribution module 44 for setting the first modulation after the power is distributed The symbol and the second modulation symbol are superimposed, wherein the constellation of the superimposed symbol is Gray mapped.

Optionally, the BPSK modulation mode is a first type of binary phase shift keying BPSK modulation mode, or a second type of binary phase shift keying BPSK modulation mode, wherein the first type of BPSK modulation mode is: modulating binary bit 0 into Real number 1, modulation of binary bit 1 into real -1; second type of BPSK modulation is: modulation of binary bit 0 to

Modulate binary bit 1 to

5 is a block diagram of a preferred structure of a superimposing module in a superimposition encoding apparatus according to an embodiment of the present invention. As shown in FIG. 5, the superimposing module 46 includes a first superimposing unit 52, and the first superimposing unit 52 is described below. .

The first superimposing unit 52 is configured to be in the BPSK modulation mode as the first type of binary phase shift keying BPSK modulation mode, and the second type of modulation mode is one of the following: QPSK modulation mode, QAM modulation mode, rectangular constellation modulation mode, diamond shape In the case of the constellation modulation method, the first modulation symbol and the second modulation symbol after power distribution are superimposed by one of the following formulas: C=Real(A)+Imag(A)·i+Sign(Real(A) ))·Real(B)+Imag(B)·i;C=Real(A)+Imag(A)·i-Sign(Real(A))·Real(B)+Imag(B)·i; C is the superimposed symbol, Real() is the real part of the modulation symbol, Imag() is the imaginary part of the modulation symbol, Sign() is the sign function, and Sign(Real(A))·Real( B) +Imag(B)·i denotes a horizontal mirroring operation for symbol B, A is a first modulation symbol after power is allocated, and B is a second modulation symbol after power is allocated.

6 is a block diagram 2 of a preferred structure of a superimposing module in a superimposition encoding apparatus according to an embodiment of the present invention. As shown in FIG. 6, the superimposing module 46 includes a second superimposing unit 62, and the second superimposing unit 62 is described below. .

The second superimposing unit 62 is configured to be in the BPSK modulation mode as the second type of BPSK modulation mode, and the second type of modulation mode is one of the following: QPSK modulation mode, QAM modulation mode, rectangular constellation modulation mode, and diamond constellation modulation mode. In this case, the first modulation symbol and the second modulation symbol after power distribution are superimposed by one of the following formulas: C=Real(A)+Imag(A)·i+e ^iθ ·(Sign(Real(A) )·Real(B)+Imag(B)·i);C=Real(A)+Imag(A)·i+e ^iθ ·(-Sign(Real(A))·Real(B)+Imag(B ·· i); where C is the superimposed symbol, Real() is the real part of the modulation symbol, Imag() is the imaginary part of the modulation symbol, Sign() is the sign function, and Sign(Real( A))·Real(B)+Imag(B)·i indicates horizontal mirroring operation for symbol B, A is the first modulation symbol after power is allocated, B is the second modulation symbol after power is allocated, and θ is horizontally mirrored. The angle of rotation.

7 is a block diagram 3 of a preferred structure of a superimposing module in a superimposition encoding apparatus according to an embodiment of the present invention. As shown in FIG. 7, the superimposing module 46 includes a third superimposing unit 72, and the third superimposing unit 72 is described below. .

The third superimposing unit 72 is configured to allocate power when the BPSK modulation mode is the first type BPSK modulation mode or the second type BPSK modulation mode, and the second type modulation mode is the 4PAM modulation mode. The first first modulation symbol and the second modulation symbol are superimposed: C=Real(A)+Imag(A)·i+(Real(B)+Imag(B)·i); C=Real(A)+Imag( A)·i+e ^iθ ·(Real(B)+Imag(B)·i); where C is the superimposed symbol, Real() is the real part of the modulation symbol, and Imag() is the pair modulation The symbol takes the imaginary part, Sign() takes the sign function, Sign(Real(A))·Real(B)+Imag(B)·i represents the horizontal mirroring operation for symbol B, and A is the first modulation symbol after the power is allocated. , B is the second modulation symbol after power is distributed, and θ is the angle of rotation after horizontal mirroring.

FIG. 8 is a block diagram showing the structure of a transmitter according to an embodiment of the present invention. As shown in FIG. 8, the transmitter 80 includes the superimposition encoding device 82 of any of the above.

FIG. 9 is a structural block diagram of a decoding apparatus according to an embodiment of the present invention. As shown in FIG. 9, the apparatus includes a receiving module 92 and a demodulating module 94, which will be described below.

The receiving module 92 is configured to receive a transmit signal sent by the transmitter, where the transmit signal is that the transmitter modulates the information flow of the first type of user by using a binary phase shift keying BPSK modulation method to obtain a first modulation symbol, and the second type The information stream of the user is modulated by the second type of modulation to obtain the second modulation symbol; and after the power is allocated to the first modulation symbol and the second modulation symbol; the first modulation symbol and the second modulation symbol after the power is allocated are superimposed And, the constellation diagram of the superposed symbols is Gray mapped, wherein the second type of modulation includes one of the following: a four-phase phase shift keying QPSK modulation method, a quadrature amplitude modulation QAM modulation method, a rectangular constellation modulation method, a diamond-shaped constellation modulation mode, a 4-pulse amplitude modulation 4PAM modulation method, and a demodulation module 94 connected to the receiving module 92, configured to demodulate the information flow of the first type of users by using a demodulation method corresponding to the modulation mode. The flow of information for the second type of user.

FIG. 10 is a block diagram showing the structure of a receiver according to an embodiment of the present invention. The receiver 100 includes the above-described decoding device 102.

In the related art, when the NOMA downlink broadcasts, the modulation mode of the edge user does not adapt to the actual scenario with low spectrum performance, the performance is not high, and the performance of the central user SIC is not high after the two user symbols are directly superimposed. In this embodiment, a superposition coding scheme for multi-user information co-channel broadcasting is provided. The downlink NOMA superposition coding scheme includes: the edge user uses BPSK modulation, the central user uses QAM or PAM (Pulse Amplitude Modulation), or the rectangular constellation or the diamond constellation modulation, and after the two users' symbols are allocated a certain power, the image is superimposed. Make the superimposed constellation map Gray mapped. The purpose is to improve the performance of multiple access in the NOMA downlink broadcast system, including the performance of edge users and the performance of central users. Compared with the traditional method, the scheme achieves a significant improvement in multiple access performance under the same spectrum effect. The scheme will be described below.

A superposition coding method for multi-user information co-channel broadcasting, comprising: a base station (a type of transmitter) uses BPSK modulation for information of a first type of user, QPSK or QAM or PAM for information of a second type of user, or a rectangle Constellation or diamond constellation modulation. It should be noted that the first type of users usually refer to cell edge users, and the second type of users usually refer to cell center users. After the base station allocates a certain power to the symbols of the two users, it is superimposed in a certain manner. The superimposed symbols are related to the modulation symbols of the two users, and the superimposed symbol constellation is Gray mapped.

The following description will be based on the combination of the modulation of the first type of users and the modulation of the second type of users.

The base station may adopt the first type of BPSK modulation mode on the edge user information to obtain a modulation symbol A ₀ , and the first type of BPSK modulation mode refers to mapping the binary bit “0” to a real number “1” and mapping the binary bit “1”. It is a real number "-1"; the central user information is modulated by QPSK or QAM, and the modulation symbol B ₀ is a complex symbol.

The base station may adopt the first type of BPSK modulation mode on the edge user information to obtain a modulation symbol A ₀ , and the first type of BPSK modulation mode refers to mapping the binary bit “0” to a real number “1” and mapping the binary bit “1”. The real number is "-1"; the central user information is modulated with a rectangular constellation, and the modulation symbol B ₀ is a complex symbol.

The base station may also adopt a first type of BPSK modulation method for the edge user information to obtain a modulation symbol A ₀ , and the second type of BPSK modulation method refers to mapping the binary bit “0” to a real number “1”, and the binary bit “1” The mapping is a real number "-1"; the central user information is modulated with a diamond constellation, and the modulation symbol B ₀ is a complex symbol.

Optionally, when the first type of BPSK modulation is used for the edge user information, and the central user uses one of the following: QPSK, QAM modulation, rectangular constellation modulation, and diamond constellation modulation, the base station allocates a certain power to the symbol A _{0 to} obtain Symbol A, assigning a certain power to symbol B _{0 to} obtain symbol B. The symbol superposition mode of the two users may be: horizontally mirroring the symbol B, directly superimposing the symbol Bm and the symbol A after the symbol B is mirrored, to obtain the superimposed symbol C. The constellation of the superimposed symbols is Gray mapped. The superimposed symbol C includes one of the following:

The superimposed symbol C can be expressed as Real(A)+Imag(A)·i+Sign(Real(A))·Real(B)+Imag(B)·i;

The superimposed symbol C can be expressed as Real(A)+Imag(A)·i-Sign(Real(A))·Real(B)+Imag(B)·i.

The base station may also adopt a second type of BPSK modulation method for the edge user information to obtain a modulation symbol A ₀ , and the second type of BPSK modulation method refers to modulating the bit "0" into

Modulate the bit "1" to

The central user information is modulated by QPSK or QAM, and the modulation symbol B ₀ is a complex symbol.

The base station may adopt a second type of BPSK modulation method for the edge user information to obtain a modulation symbol A ₀ , and the second type of BPSK modulation method refers to modulating the bit “0” to

Modulate the bit "1" to

The central user information is modulated with a rectangular constellation, and the modulation symbol B ₀ is a complex symbol.

The base station may also adopt a second type of BPSK modulation method for the edge user information to obtain a modulation symbol A ₀ , and the second type of BPSK modulation method refers to modulating the bit “0” to

Modulate the bit "1" to

The central user information is modulated with a diamond constellation diagram, and the modulation symbol B ₀ is a complex symbol.

Optionally, when the second type of BPSK modulation is used for the edge user information, and the center user uses one of the following: QPSK, QAM modulation, rectangular constellation modulation, and diamond constellation modulation, the base station allocates a certain power to the symbol A _{0 to} obtain Symbol A, assigning a certain power to symbol B _{0 to} obtain symbol B. The symbol superposition method is: horizontally mirroring and 45-degree phase rotation of the symbol B, and directly superimposing the symbol Br and the symbol A after the symbol B is mirrored and rotated 45 degrees, to obtain the superimposed symbol C. The constellation of the superimposed symbols is Gray mapped. The superimposed symbol C includes one of the following:

The superimposed symbol C can be expressed as Real(A)+Imag(A)·i+e ^iπ/4 ·(Sign(Real(A))·Real(B)+Imag(B)·i);

The superimposed symbol C can be expressed as Real(A)+Imag(A)·i+e ^iπ/4 ·(-Sign(Real(A))·Real(B)+Imag(B)·i) ;

The base station may also adopt the first type of BPSK modulation mode for the edge user information to obtain the modulation symbol A ₀ , and the first type of BPSK modulation mode refers to modulating the bit "0" to 1 and the bit "1" to -1; The central user information is modulated with 4PAM, and the modulation symbol B ₀ is a pure imaginary symbol.

After the above modulation mode is adopted, the base station allocates a certain power to the symbol A _{0 to} obtain the symbol A, and allocates a certain power to the symbol B ₀ to obtain the symbol B. The superposition method may be: superimposing the symbol B and the symbol A directly to obtain the superimposed symbol C. The constellation of the superimposed symbols is Gray mapped. The superimposed symbol C can be expressed as Real(A)+Imag(A)·i+(Real(B)+Imag(B)·i);

Modulate the bit "1" to

The central user information is modulated with 4PAM, and the modulation symbol B ₀ is a pure imaginary symbol.

After the above modulation mode is adopted, the base station allocates a certain power to the symbol A _{0 to} obtain the symbol A, and allocates a certain power to the symbol B ₀ to obtain the symbol B. The corresponding superposition method may be: performing a 45-degree phase rotation on the symbol B, and superimposing the symbol Br and the symbol A after the symbol B is rotated 45 degrees, to obtain the superimposed symbol C. The constellation of the superimposed symbols is Gray mapped. The superimposed symbol C can be expressed as Real(A)+Imag(A)·i+e ^iπ/4 ·(Real(B)+Imag(B)·i);

Corresponding to the receiver, in the embodiment, a demodulation method for multi-user information co-channel broadcasting is further provided, comprising: receiving a transmission signal from a transmitter, wherein the transmission signal is an edge user on the transmitter The information flow BPSK modulation is modulated by superimposing the central user information stream QPSK or QAM or PAM, or a rectangular constellation or a diamond constellation, and then generated by the superimposed symbols. The received signal is demodulated according to its type using a corresponding demodulation method.

For example, if the receiver is a cell edge user, the first part of the signal to be sent to the cell edge user is demodulated from the received signal by BPSK; and the user information corresponding to the cell edge user is decoded from the first part of the signal.

If the receiver is a cell center user, the first part of the signal to be sent to the cell edge user is demodulated from the received signal by BPSK; the first part of the received signal is removed, and QPSK is pressed from the remaining part of the signal or QAM or rectangular constellation or PAM, or diamond constellation mode, or QAM, rectangular constellation, PAM, or diamond constellation in the form of 45 degree phase rotation to demodulate the second part of the signal to be sent to the center user of the cell; The user information corresponding to the cell center user is decoded in the second part of the signal.

Preferred embodiments of the invention are described below.

11 is a schematic diagram of a wireless broadcast communication system according to a preferred embodiment of the present invention. As shown in FIG. 11, the base station transmits multi-user information to two user equipments (UE1 and UE2), that is, simultaneously transmits edge user information to the edge user UE1. (Remote), the central user information is transmitted to the central user UE2 (near end).

FIG. 12 is a process diagram of a two-user information co-channel broadcast at a transmitting end according to a preferred embodiment of the present invention. As shown in FIG. 12, first, an edge user information stream and a center user information stream C1, C2 are composed of a dual information bit stream I1. I2 is obtained by Turbo coding, and the base station modulates the edge user information stream and the central user information stream C1 and C2 into a complex symbol sequence S1 and S2 with a certain power according to the channel condition between the UE and the terminal UE according to the modulation scheme of the matched channel. The spectrum effect of the edge user UE1 is smaller than that of the center user UE2. According to the embodiment of the present invention, the base station adopts BPSK modulation for C1, QPSK or QAM or rectangular constellation or PAM for C2, or diamond-shaped constellation modulation of 60 degree apex angle.

Then, S1 and S2 are superimposed in a certain way so that the superimposed constellation is Gray mapped. Suppose that the complex symbol sequence S1 with a certain power is x1+y1·i, and the complex symbol sequence S2 with a certain power is x2+y2·i, including the power of S1 being greater than the power of S2.

The overlay method includes one of the following:

The superposition method may be that the symbol S of the complex symbol sequence S1 and the complex symbol sequence S2 is directly superimposed, and the directly superposed symbol sequence S3 may be expressed as (S1+S) or (x1+y1·i). +Sign(x1)·x2+y2·i, or (x1+y1·i)-Sign(x1)·x2+y2·i;

The superposition method may also be that the symbol S of the complex symbol sequence S1 and the complex symbol sequence S2 and the 45-degree phase rotation are directly superimposed, and the directly superposed complex symbol sequence S3 may be expressed as (S1+S) or as ( X1+y1·i)+e ^iπ/4 ·(Sign(x1)·x2+y2·i), or (x1+y1·i)+e ^iπ/4 ·(-Sign(x1)·x2+y2· i).

The superposition method may be that the complex symbol sequence S1 and the complex symbol sequence S2 are directly superimposed, and the directly superposed complex symbol sequence S3 may be expressed as (S1+S2) or as (x1+y1·i)+(x2+y2). · i).

The superposition method may be that the symbol S of the complex symbol sequence S1 and the complex symbol sequence S2 after 45-degree phase rotation is directly superimposed, and the directly superposed complex symbol sequence S3 may be expressed as (S1+S) or (x1+). Y1·i)+e ^iπ/4 ·(x2+y2·i).

The constellation of the complex-coded complex symbol S3 has a Gray attribute, and the superposed symbol constellation may have a Gray attribute by other methods.

Finally, the base station forms the superposed symbol to form a transmission signal T, and sends it to the intra-cell user UE1 and the central user UE2.

Embodiment 1

In order to emphasize the characteristics in the embodiments of the present invention, the following exemplary embodiments are combined with the simulation results to illustrate that the performance of the embodiments of the present invention is significantly improved.

A downlink NOMA superposition coding scheme, the base station uses the first type of BPSK modulation to obtain the modulation symbol S1, and allocates a certain power to the S1. The first type of BPSK modulation refers to modulating the bit "0" to 1, and the bit is The "1" modulation is -1; the modulation symbol S2 is obtained by QPSK modulation for the central user information, and a certain power is allocated to S2. The base station mirrors the symbol S2 horizontally, and the mirrored symbol S can be represented as Sign(x1)·x2+y2·i. The symbol S after the S2 mirroring and the symbol S1 are directly superimposed to obtain the superimposed symbol S3. The constellation of the superimposed symbol S3 is Gray mapped.

FIG. 13 is a schematic diagram of a process of a conventional superimposition coding method according to Embodiment 1 of the present invention. As shown in FIG. 13, a superposition coding of a conventional superposition coding mode 1: a base station uses QPSK modulation for edge user information, and QPSK modulation for central user information. The two user information S1 and S2 are directly superimposed.

Superposition coding mode two superposition coding according to Embodiment 1 of the present invention: the base station uses the first type of BPSK modulation on the edge user information: modulating bit "0" to 1, modulating bit "1" to -1; using QPSK for central user information Modulation, the signal after mirroring of the central user signal and the edge user signal are superimposed. FIG. 14 is a schematic diagram of a process of superimposing coding mode two superimposition coding according to a first embodiment of the present invention. As shown in Figure 14, the complete superimposition coding process is as follows:

Step 1. The symbol S2 is mirrored. It can be seen from S1 that when Sign(x1)=-1, S is -x2+y2·i, which is equivalent to S2 for horizontal mirroring. When Sign(x1)=1, S is x2+y2·i, which is the same as S2, that is, S2 remains unchanged;

Step 2: The symbol S1 is directly superimposed with the mirrored symbol S to obtain the superimposed symbol S3.

The edge users of the two superimposed coding modes have the same spectral effect, and the central user has the same spectral effect. FIG. 15 is a comparison diagram of the performance of the superimposed coding mode 2 and the traditional superimposition coding mode according to the first embodiment of the present invention, as shown in FIG. It is shown that the edge user performance of the superposition coding mode 2 of the embodiment of the present invention is significantly higher than that of the traditional superposition coding mode one when the performance is consistent at the center; FIG. 16 is a superimposition coding mode 2 according to the first embodiment of the present invention. The traditional user performance comparison diagram of the conventional superposition coding mode, as shown in FIG. 16, when the edge performance is consistent, the central user performance of the superposition coding mode 2 of the first embodiment is significantly higher than that of the traditional superposition coding mode 1.

Example two

In order to emphasize the characteristics in the embodiments of the present invention, the following exemplary embodiment 2 is preferably combined with the simulation results to show that the performance of the embodiment of the present invention is significantly improved.

A downlink NOMA superposition coding scheme, in which a base station uses a second type of BPSK modulation to obtain a modulation symbol S1, and allocates a certain power to S1. The second type of BPSK modulation method modulates a bit "0" to

Modulate the bit "1" to

Modulation symbol S2 is obtained by QPSK modulation for the central user information, and a certain power is allocated to S2. The base station performs horizontal mirroring and 45-degree phase rotation on the symbol S2, and the symbol S after mirroring and 45-degree phase rotation can be expressed as e ^iπ/4 · (Sign(x1)·x2+y2·i). The symbol S and the symbol S1 after mirroring and 45-degree phase rotation are superimposed to obtain the superimposed symbol S3. The constellation of the superimposed symbol S3 is Gray mapped.

In the first embodiment of the present invention, the superposition coding method is superimposed and encoded according to the embodiment of the present invention. The base station uses the second type of BPSK modulation mode for the edge user information: the bit "0" is modulated into

Modulate the bit "1" to

The QPSK modulation is used for the central user information, and the signal of the central user signal and the phase rotation of the 45 degree phase is superimposed with the edge user signal. FIG. 17 is a schematic diagram of a process of superimposing coding mode 3 according to Embodiment 2 of the present invention. As shown in FIG. 17, the complete superposition coding process is as follows:

Step 1, symbol S2 is mirrored and 45 degree phase is rotated. It can be known from S1 that when Sign(x1)=-1, S is e ^iπ/4 ·(-x2+y2·i), which is equivalent to S2 being horizontally mirrored. 45 degree phase rotation. When Sign(x1)=1, S is e ^iπ/4 ·(x2+y2·i), which is the symbol after S2 is rotated by 45 degrees;

Step 2. The mirrored symbol S and the symbol S1 are superimposed after 45 degree phase rotation on the constellation diagram to obtain the superimposed symbol S3.

The edge users of the two superimposition coding modes are set to be consistent, and the spectrum performance of the center user is consistent. When the performance of the center is consistent, the edge user performance of the superposition coding mode 3 in the embodiment of the present invention is significantly higher than that of the traditional superposition coding mode. User performance, signal to noise ratio gain is consistent with Figure 15 in Example 1. When the edge performance is consistent, the central user performance of the superimposition coding mode 3 in the embodiment of the present invention is significantly higher than the central user performance of the conventional superposition coding mode one, and the signal-to-noise ratio gain is consistent with FIG. 16 in the first embodiment.

Example three

In order to emphasize the characteristics in the embodiments of the present invention, the following exemplary embodiment 3 is preferably combined with the simulation results to show that the performance of the embodiment of the present invention is significantly improved.

A downlink NOMA superposition coding scheme, the base station uses the first type of BPSK modulation to obtain the modulation symbol S1 for the edge user information, and allocates a certain power to the S1. The first type of BPSK modulation refers to modulating the bit "0" to 1 and the bit " 1" modulation is -1; modulation of the central user information is performed with 4-point PAM (4PAM modulation) to obtain a modulation symbol S2, and a certain power is allocated to S2. The symbol S1 and the symbol S2 are directly superimposed to obtain the superimposed symbol S3. The constellation of the superimposed symbol S3 is Gray mapped.

In the first embodiment of the present invention, the superposition coding method is superimposed and coded according to the embodiment of the present invention. The base station uses the first type of BPSK modulation mode for the edge user information: the bit "0" is modulated to 1, and the bit is "1". "Modulation is -1; 4PAM modulation is used for the central user information, and the edge user signal S1 and the center user signal S2 are superimposed to obtain the superimposed symbol S3. FIG. 18 is a schematic diagram of a process of superimposing coding mode 4 according to Embodiment 3 of the present invention. As shown in FIG. 18, the spectral effects of the edge users of the two superimposition coding modes are consistent, and the spectrum efficiency of the center user is consistent, FIG. 19 is according to the present invention. In the third embodiment of the present invention, the superimposed coding mode 4 and the conventional superimposition coding mode and the edge user performance comparison diagram, as shown in FIG. 19, when the center performance is consistent, the edge user performance of the fourth embodiment of the superposition coding mode of the third embodiment of the present invention is significantly higher. Edge user performance in traditional superposition coding mode one. 20 is a comparison diagram of a central user performance of a superposition coding method 4 and a conventional superposition coding method according to Embodiment 3 of the present invention. As shown in FIG. 20, when the edge performance is consistent, the central user performance of the superposition coding mode 4 in the embodiment of the present invention is shown in FIG. It is significantly higher than the central user performance of the traditional superposition coding method.

Example four

In order to emphasize the characteristics in the embodiments of the present invention, the following exemplary embodiment 4 is preferably combined with the simulation results to show that the performance of the embodiment of the present invention is significantly improved.

A downlink NOMA superposition coding scheme, the base station uses the second type of BPSK modulation to obtain the modulation symbol S1 for the edge user information, and allocates a certain power to the S1. The second type of BPSK modulation method refers to modulating the bit "0" into

Modulate the bit "1" to

The central user information is modulated by a 4-point PAM method (4PAM) to obtain a modulation symbol S2, and a certain power is allocated to S2. The base station rotates the symbol S2 in a 45-degree phase, and the symbol after the 45-degree phase rotation can be expressed as e ^iπ/4 ·(x2+y2·i). The symbol S and the symbol S1 are superimposed to obtain the superimposed symbol S3. The constellation of the superimposed symbol S3 is Gray mapped.

Compared with the conventional superposition coding method 1 in the first embodiment, the superposition coding method is superimposed and coded according to the embodiment of the present invention: the base station uses the second type of BPSK modulation mode for the edge user information: the bit "0" is modulated into

Modulate the bit "1" to

The 4PAM modulation is used for the central user information, and the edge user signal and the central user signal after the 45-degree phase rotation are superimposed to obtain the superimposed symbol S3. 21 is a schematic diagram of a process of superimposing coding mode 5 according to Embodiment 4 of the present invention. As shown in FIG. 21, the edge users of the two superimposition coding modes are set to have the same spectral effect, and the central users have the same spectral performance, and the performance is consistent at the center. In the embodiment of the present invention, the edge user performance of the superimposition coding mode 5 is significantly higher than that of the traditional superposition coding mode 1 , and the signal to noise ratio gain is consistent with FIG. 19 in the third embodiment. When the edge performance is consistent, the central user performance of the superimposition coding mode 5 in the embodiment of the present invention is significantly higher than the central user performance of the conventional superposition coding mode 1. The signal-to-noise ratio gain is consistent with FIG. 20 in the third embodiment.

Embodiment 5

In order to emphasize the characteristics in the embodiments of the present invention, the following exemplary embodiment 5 is preferably combined with the simulation results to show that the performance of the embodiment of the present invention is significantly improved.

A downlink NOMA superposition coding scheme, the base station uses the first type of BPSK modulation to obtain the modulation symbol S1 for the edge user information, and allocates a certain power to the S1. The first type of BPSK modulation refers to modulating the bit "0" to 1 and the bit " 1" modulation is -1; modulation of the central user information is performed with 8-point rectangular constellation modulation (8PAM modulation) to obtain a modulation symbol S2, and a certain power is allocated to S2. The base station mirrors the symbol S2 horizontally, and the mirrored symbol S can be represented as Sign(x1)·x2+y2·i. The symbol S after the S2 mirroring and the symbol S1 are directly superimposed to obtain the superimposed symbol S3. The constellation of the superimposed symbol S3 is Gray mapped.

In the first embodiment of the present invention, the superposition coding method is superimposed and encoded according to the embodiment of the present invention. The base station uses the first type of BPSK modulation mode for the edge user information: the bit "0" is modulated to 1, and the bit is "1". Modulation is -1; 8PAM modulation is used for central user information, signal and edge users after central user signal mirroring Signal superposition. FIG. 22 is a schematic diagram of a process of superimposing coding mode six according to Embodiment 5 of the present invention. As shown in FIG. 22, the complete superimposition coding process is as follows:

The spectral effects of the edge users of the two superimposed coding modes are set to be consistent, and the spectral efficiency of the central user is consistent. FIG. 23 is a comparison diagram of the performance of the superimposed coding mode 6 and the traditional superimposition coding mode according to the fifth embodiment of the present invention, as shown in FIG. 23 . It is shown that the edge user performance of the superposition coding mode 6 of the fifth embodiment of the present invention is significantly higher than that of the traditional superposition coding mode one when the performance is consistent at the center. FIG. 24 is a comparison diagram of a central user performance of a superimposition coding method 6 and a conventional superposition coding mode according to Embodiment 5 of the present invention. As shown in FIG. 24, when the edge performance is consistent, the central user performance of the superposition coding mode 6 in the embodiment of the present invention is shown in FIG. It is significantly higher than the central user performance of the traditional superposition coding method.

Embodiment 6

In order to emphasize the characteristics in the embodiments of the present invention, the following exemplary embodiment 6 is preferably combined with the simulation results to show that the performance of the embodiment of the present invention is significantly improved.

A downlink NOMA superposition coding scheme, the base station uses the second type of BPSK modulation to obtain the modulation symbol S1 for the edge user information, and allocates a certain power to the S1, and the second type of BPSK modulation refers to modulating the bit "0" to

Modulate the bit "1" to

For the central user information, the 8-bit rectangular constellation modulation (8PAM modulation) is used to obtain the modulation symbol S2, and a certain power is allocated to S2. The base station performs horizontal mirroring and 45-degree phase rotation on the symbol S2, and the symbol S after mirroring and 45-degree phase rotation can be expressed as e ^iπ/4 · (Sign(x1)·x2+y2·i). The symbol S and the symbol S1 after mirroring and 45-degree phase rotation are superimposed to obtain the superimposed symbol S3. The constellation of the superimposed symbol S3 is Gray mapped.

Compared with the conventional superposition coding mode 1 in the first embodiment, the superposition coding mode is superimposed and coded according to the embodiment of the present invention: the base station uses the second type of BPSK modulation mode for the edge user information: the bit "0" is modulated into

Modulate the bit "1" to

8PAM modulation is used for the central user information, and the signal of the central user signal and the phase rotation of the 45 degree phase is superimposed with the edge user signal. 25 is a schematic diagram of a process of superimposing coding mode 7 according to Embodiment 6 of the present invention. As shown in FIG. 25, the complete superimposition coding process is as follows:

The edge users of the two superimposed coding modes are consistent in performance, and the spectrum performance of the central user is consistent. When the performance of the center is consistent, the edge user performance of the superimposition coding mode 7 in the embodiment of the present invention is significantly higher than that of the traditional superposition coding mode. User performance, signal to noise ratio gain is consistent with Figure 23 in Example 5. When the edge performance is consistent, the performance of the central user of the superposition coding mode 7 in the embodiment of the present invention is significantly higher than that of the traditional superposition coding mode 1. The signal-to-noise ratio gain is consistent with FIG. 24 in the fifth embodiment.

Example 7

In order to emphasize the characteristics in the embodiments of the present invention, the following exemplary embodiment 7 is preferably combined with the simulation results to show that the performance of the embodiment of the present invention is significantly improved.

A downlink NOMA superposition coding scheme, the base station uses the first type of BPSK modulation to obtain the modulation symbol S1 for the edge user information, and allocates a certain power to the S1. The first type of BPSK modulation refers to modulating the bit "0" to 1 and the bit " 1" modulation is -1; the central user information is modulated with a diamond constellation of 4 points and 60 degrees apex angle to obtain a modulation symbol S2, and a certain power is allocated to S2. The base station mirrors the symbol S2 horizontally, and the mirrored symbol S can be represented as -Sign(x1)·x2+y2·i. The symbol S after the S2 mirroring and the symbol S1 are directly superimposed to obtain the superimposed symbol S3. The constellation of the superimposed symbol S3 is Gray mapped.

In the first embodiment of the present invention, the superposition coding method is superimposed and encoded according to the embodiment of the present invention. The base station uses the first type of BPSK modulation mode for the edge user information: the bit "0" is modulated to 1, and the bit is "1". The modulation is -1; the center user information is modulated with a diamond constellation of 4 degrees and 60 degrees, and the signal after the central user signal is mirrored and the edge user signal are superimposed. FIG. 26 is a schematic diagram of a process of superimposing coding mode according to Embodiment 7 of the present invention. As shown in FIG. 26, the complete superposition coding process is as follows:

Step 1. The symbol S2 is mirrored. It can be seen from S1 that when Sign(x1)=1, S is -x2+y2·i, which is equivalent to S2 for horizontal mirroring. When Sign(x1)=-1, S is x2+y2·i, which is the same as S2, that is, S2 remains unchanged;

The spectral effects of the edge users of the two superimposed coding modes are set to be consistent, and the spectral efficiency of the central user is consistent. FIG. 27 is a comparison diagram of the performance of the superimposed coding mode 8 and the traditional superimposition coding mode according to the seventh embodiment of the present invention, such as As shown in FIG. 27, when the performance of the center is consistent, the edge user performance of the superposition coding mode 8 of the seventh embodiment of the present invention is significantly higher than that of the conventional superposition coding mode one. 28 is a comparison diagram of a central user performance of a superposition coding method 8 and a conventional superposition coding mode according to Embodiment 7 of the present invention, as shown in FIG. 28, a central user performance of coding mode 1.

Example eight

In order to emphasize the characteristics in the embodiments of the present invention, the following exemplary embodiment 8 is preferably combined with the simulation results to illustrate a significant improvement in performance of the embodiment of the present invention.

Modulate the bit "1" to

The modulation symbol S2 is obtained by modulating the central user information with a diamond constellation of 4 points and 60 degrees apex angle, and a certain power is allocated to S2. The base station performs horizontal mirroring and 45-degree phase rotation on the symbol S2, and the symbol S after mirroring and 45-degree phase rotation can be expressed as e ^iπ/4 · (Sign(x1)·x2+y2·i). The symbol S and the symbol S1 after mirroring and 45-degree phase rotation are superimposed to obtain the superimposed symbol S3. The constellation of the superimposed symbol S3 is Gray mapped.

Compared with the conventional superposition coding mode 1 in the first embodiment, the superposition coding mode is superimposed and coded according to the embodiment of the present invention: the base station uses the second type of BPSK modulation mode for the edge user information: modulating the bit "0" into

Modulate the bit "1" to

The center user information is modulated with a 4-point diamond constellation, and the center user signal is mirrored and the 45-degree phase rotated signal is superimposed with the edge user signal. 29 is a schematic diagram of a process of superimposing coding mode according to Embodiment 8 of the present invention. As shown in FIG. 29, the complete superimposition coding process is as follows:

The edge users of the two superimposed coding modes are consistent in performance, and the central users have the same spectral effect. When the performance of the center is consistent, the edge user performance of the superimposition coding mode 9 of the present invention is significantly higher than that of the traditional superposition coding mode. The signal-to-noise ratio gain is identical to that of Figure 27 in the seventh embodiment. When the edge performance is consistent, the performance of the central user of the superimposition coding mode 9 in the embodiment of the present invention is significantly higher than that of the traditional superposition coding mode 1. The signal-to-noise ratio gain is consistent with FIG. 28 in the seventh embodiment.

Obviously, those skilled in the art should understand that the above modules or steps of the embodiments of the present invention can be implemented by a general computing device, which can be concentrated on a single computing device or distributed in multiple computing devices. Alternatively, they may be implemented by program code executable by the computing device such that they may be stored in the storage device by the computing device and, in some cases, may be different from The steps shown or described are performed sequentially, or they are separately fabricated into individual integrated circuit modules, or a plurality of modules or steps thereof are fabricated into a single integrated circuit module. Thus, the invention is not limited to any specific combination of hardware and software.

The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Industrial applicability

As described above, the above embodiments and preferred embodiments solve the problem that the multi-user performance is not high when multiple users are directly superimposed in the related art, thereby achieving the effect of improving multi-user performance.

Claims

A superposition coding method, comprising:

The first type of user information is modulated by a binary phase shift keying BPSK modulation method to obtain a first modulation symbol, and the second type of user information is modulated by a second type of modulation method to obtain a second modulation symbol;

Allocating power to the first modulation symbol and the second modulation symbol;

And superposing the first modulation symbol and the second modulation symbol after the power is allocated, wherein the constellation of the superposed symbols is Gray mapped.
The method according to claim 1, wherein the first type of users are cell edge users within a first predetermined range of cells, and the second type of cells are cell center users within a second predetermined range of cells.
The method of claim 1 wherein

The BPSK modulation mode is a first type of binary phase shift keying BPSK modulation mode, or a second type of binary phase shift keying BPSK modulation mode, wherein the first type of BPSK modulation mode is: modulating binary bit 0 into Real number 1, the binary bit 1 is modulated to a real number -1; the second type of BPSK modulation is: modulating the binary bit 0 to
Modulate binary bit 1 to

The second type of modulation method is one of the following: a four-phase phase shift keying QPSK modulation method, a quadrature amplitude modulation QAM modulation method, a 4-pulse amplitude modulation 4PAM modulation method, a rectangular constellation modulation method, and a diamond constellation modulation method.
The method of claim 3, wherein

The BPSK modulation mode is a first type of binary phase shift keying BPSK modulation mode, and the second type of modulation mode is one of the following: QPSK modulation mode, QAM modulation mode, rectangular constellation modulation mode, and diamond constellation modulation mode. In the case of the first modulation symbol and the second modulation symbol after the power is allocated by one of the following formulas:

C=Real(A)+Imag(A)·i+Sign(Real(A))·Real(B)+Imag(B)·i;

C=Real(A)+Imag(A)·i-Sign(Real(A))·Real(B)+Imag(B)·i;

Where C is the superimposed symbol, Real() is the real part of the modulation symbol, Imag() is the imaginary part of the modulation symbol, and Sign() is the sign function, Sign(Real(A))·Real (B) +Imag(B)·i denotes a horizontal mirroring operation for symbol B, A is a first modulation symbol after power is allocated, and B is a second modulation symbol after power is allocated.
The method of claim 3, wherein

The BPSK modulation scheme is a second type of BPSK modulation scheme, and the second type of modulation scheme is one of the following: a QPSK modulation scheme, a QAM modulation scheme, a rectangular constellation modulation scheme, and a diamond constellation modulation scheme. One of the following formulas, superimposing the first modulation symbol and the second modulation symbol after power distribution:

C=Real(A)+Imag(A)·i+e iθ ·(Sign(Real(A))·Real(B)+Imag(B)·i);

C=Real(A)+Imag(A)·i+e iθ ·(-Sign(Real(A))·Real(B)+Imag(B)·i);

Where C is the superimposed symbol, Real() is the real part of the modulation symbol, Imag() is the imaginary part of the modulation symbol, and Sign() is the sign function, Sign(Real(A))·Real (B) +Imag(B)·i indicates horizontal mirroring operation for symbol B, A is the first modulation symbol after power is allocated, B is the second modulation symbol after power distribution, and θ is the angle of rotation after horizontal mirroring.
The method of claim 3, wherein

In the case where the BPSK modulation method is the first type BPSK modulation method or the second type BPSK modulation method, and the second type modulation method is a 4PAM modulation method, the power is allocated by one of the following formulas. The subsequent first modulation symbol and the second modulation symbol are superimposed:

C=Real(A)+Imag(A)·i+(Real(B)+Imag(B)·i);

C=Real(A)+Imag(A)·i+e iθ ·(Real(B)+Imag(B)·i);

Where C is the superimposed symbol, Real() is the real part of the modulation symbol, Imag() is the imaginary part of the modulation symbol, and Sign() is the sign function, Sign(Real(A))·Real (B) +Imag(B)·i indicates horizontal mirroring operation for symbol B, A is the first modulation symbol after power is allocated, B is the second modulation symbol after power distribution, and θ is the angle of rotation after horizontal mirroring.
A decoding method comprising:

Receiving a transmit signal sent by the transmitter, wherein the transmit signal is modulated by the transmitter for the information flow of the first type of user by using a binary phase shift keying BPSK modulation method to obtain a first modulation symbol, for the second type of user The information stream is modulated by the second type of modulation to obtain a second modulation symbol; and after the power is allocated to the first modulation symbol and the second modulation symbol; the first modulation symbol after the power is allocated, the first The two modulation symbols are obtained by superposition, and the constellation of the superposed symbols is Gray mapped, wherein the second type of modulation includes one of the following: four-phase phase shift keying QPSK modulation mode, quadrature amplitude modulation QAM modulation Mode, rectangular constellation modulation mode, diamond constellation modulation mode, 4-pulse amplitude modulation 4PAM modulation mode;

The information stream of the first type of user and/or the information stream of the second type of user are demodulated by using a demodulation method corresponding to the modulation mode.
A symbol superimposing device comprising:

The modulation module is configured to modulate the information flow of the first type of users by using a binary phase shift keying BPSK modulation method to obtain a first modulation symbol, and modulate the information flow of the second type of user by using a second type of modulation manner to obtain a second modulation. symbol;

An allocating module, configured to allocate power to the first modulation symbol and the second modulation symbol;

And a superimposing module, configured to superimpose the first modulation symbol and the second modulation symbol after the power is allocated, wherein the constellation of the superimposed symbol is Gray mapped.
The apparatus according to claim 8, wherein the first type of users are cell edge users within a first predetermined range of cells, and the second type of cells are cell center users within a second predetermined range of cells.
The device according to claim 8, wherein

The BPSK modulation mode is a first type of binary phase shift keying BPSK modulation mode, or a second type of binary phase shift keying BPSK modulation mode, wherein the first type of BPSK modulation mode is: modulating binary bit 0 into Real number 1, the binary bit 1 is modulated to a real number -1; the second type of BPSK modulation is: modulating the binary bit 0 to
Modulate binary bit 1 to

The second type of modulation method is one of the following: a four-phase phase shift keying QPSK modulation method, a quadrature amplitude modulation QAM modulation method, a 4-pulse amplitude modulation 4PAM modulation method, a rectangular constellation modulation method, and a diamond constellation modulation method.
The apparatus of claim 10 wherein said overlay module comprises:

The first superimposing unit is configured to adopt a first type of binary phase shift keying BPSK modulation mode in the BPSK modulation mode, and the second type of modulation mode is one of the following: QPSK modulation mode, QAM modulation mode, and rectangular constellation modulation mode. In the case of a mode and a diamond constellation modulation mode, the first modulation symbol and the second modulation symbol after power distribution are superimposed by one of the following formulas:

C=Real(A)+Imag(A)·i+Sign(Real(A))·Real(B)+Imag(B)·i;

C=Real(A)+Imag(A)·i-Sign(Real(A))·Real(B)+Imag(B)·i;

Where C is the superimposed symbol, Real() is the real part of the modulation symbol, Imag() is the imaginary part of the modulation symbol, and Sign() is the sign function, Sign(Real(A))·Real (B) +Imag(B)·i denotes a horizontal mirroring operation for symbol B, A is a first modulation symbol after power is allocated, and B is a second modulation symbol after power is allocated.
The apparatus of claim 10 wherein said overlay module comprises:

The second superimposing unit is configured to be in the BPSK modulation mode of the second type BPSK modulation mode, and the second type of modulation mode is one of the following: QPSK modulation mode, QAM modulation mode, rectangular constellation modulation mode, diamond constellation diagram In the case of the modulation mode, the first modulation symbol and the second modulation symbol after power distribution are superimposed by one of the following formulas:

C=Real(A)+Imag(A)·i+e iθ ·(Sign(Real(A))·Real(B)+Imag(B)·i);

C=Real(A)+Imag(A)·i+e iθ ·(-Sign(Real(A))·Real(B)+Imag(B)·i);

Where C is the superimposed symbol, Real() is the real part of the modulation symbol, Imag() is the imaginary part of the modulation symbol, and Sign() is the sign function, Sign(Real(A))·Real (B) +Imag(B)·i indicates horizontal mirroring operation for symbol B, A is the first modulation symbol after power is allocated, B is the second modulation symbol after power distribution, and θ is the angle of rotation after horizontal mirroring.
The apparatus of claim 10 wherein said overlay module comprises:

The third superimposing unit is configured to: when the BPSK modulation scheme is the first type BPSK modulation scheme or the second type BPSK modulation scheme, and the second type modulation scheme is a 4PAM modulation scheme, One of the formulas, superimposing the first modulation symbol and the second modulation symbol after power is allocated:

C=Real(A)+Imag(A)·i+Real(B)+Imag(B)·i);

C=Real(A)+Imag(A)·i+e iθ ·(Real(B)+Imag(B)·i);

Where C is the superimposed symbol, Real() is the real part of the modulation symbol, Imag() is the imaginary part of the modulation symbol, and Sign() is the sign function, Sign(Real(A))·Real (B) +Imag(B)·i indicates horizontal mirroring operation for symbol B, A is the first modulation symbol after power is allocated, B is the second modulation symbol after power distribution, and θ is the angle of rotation after horizontal mirroring.
A transmitter comprising the apparatus of any one of claims 8 to 13.
A decoding device comprising:

a receiving module, configured to receive a transmit signal sent by the transmitter, where the transmit signal is modulated by the transmitter to use a binary phase shift keying BPSK modulation method to obtain a first modulation symbol for the information flow of the first type of user, The information flow of the second type of user is modulated by the second type of modulation to obtain the second modulation symbol; and after the power is allocated to the first modulation symbol and the second modulation symbol; the first modulation after power is allocated The symbol, the second modulation symbol is obtained by superposition, and the constellation of the superimposed symbol is Gray mapped, wherein the second type of modulation includes one of the following: a four-phase phase shift keying QPSK modulation method, Quadrature amplitude modulation QAM modulation method, rectangular constellation modulation method, diamond constellation modulation method, 4-pulse amplitude modulation 4PAM modulation method;

The demodulation module is configured to demodulate the information flow of the first type of user and/or the information flow of the second type of user by using a demodulation manner corresponding to the modulation mode.
A receiver comprising the apparatus of claim 15.