CN105790816B - Multi-antenna downlink data transmission method and equipment - Google Patents
Multi-antenna downlink data transmission method and equipment Download PDFInfo
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- CN105790816B CN105790816B CN201410837075.5A CN201410837075A CN105790816B CN 105790816 B CN105790816 B CN 105790816B CN 201410837075 A CN201410837075 A CN 201410837075A CN 105790816 B CN105790816 B CN 105790816B
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Abstract
The invention discloses a multi-antenna downlink data transmission method and equipment, wherein the method comprises the following steps: forming an nth type optimized modulation symbol by the nth type data stream, wherein the value range of N is more than or equal to 1 and less than or equal to N, and N is an integer more than 1; superposing the N types of optimized modulation symbols to obtain an M type symbol, wherein the value of M is equal to N + 1; carrying out multi-antenna transmit diversity processing on the M-type symbol to form a transmit signal; and sending the transmission signal.
Description
Technical Field
The present invention relates to wireless communication technologies, and in particular, to a method and an apparatus for transmitting downlink data of multiple antennas.
Background
Some of the most important factors in determining whether a wireless communication system has high capacity and high performance are interference and spectral efficiency. As for a multi-user equipment communication system, interference between different user equipments is a major factor limiting the system capacity.
The interference of multi-user equipment in a cell includes interference between different user equipment in the cell and interference of different user equipment between cells. In the Orthogonal Multiple Access (OMA) scheme, each ue uses strictly mutually Orthogonal "subchannels" for transmission, so that there is no mutual interference between ue information in a cell during demodulation, such as the Orthogonal Frequency Division Multiple Access (OFDMA) and Single Carrier Frequency division Multiple Access (SC-FDMA) schemes adopted by LTE-Advanced.
Future radio Access requires further capacity or spectral efficiency improvements by multiples, and the Non-Orthogonal Multiple Access (NOMA Non-Orthogonal Multiple Access) scheme is selected as an alternative to future radio Access. In the NOMA scheme, information of each user equipment is transmitted over "the entire channel", which corresponds to the OMA scheme. A modulation scheme suitable for the NOMA system is called "superposition coding", for example, downlink NOMA, a transmitter superposes modulation symbols of information of different user equipments, and transmits the superposed symbols to a plurality of receivers on the same time-frequency resource, different user equipments extract their own information from the received signals, a weaker user equipment (an edge user equipment is a weaker user equipment relative to a central user equipment) can directly demodulate its own information, a stronger user equipment (a central user equipment is a stronger user equipment relative to the edge user equipment) uses a Successive Interference Cancellation (SIC) receiver to demodulate its own information, that is, firstly demodulates the information of the weaker user equipment, and then demodulates its own information after removing the information of the weaker user equipment. Downlink NOMA can achieve larger system capacity than downlink OMA, and in particular, the NOMA mode can preferentially improve the capacity of the user equipment at the edge of the cell while basically maintaining the high throughput of the central user equipment.
However, in a real fading channel, the signal is likely to travel a deep fade in a single path, resulting in degraded performance. The diversity technology enables signals to be transmitted on a plurality of fading paths, and information can be correctly received as long as one path signal is strong, so that performance can be effectively improved, for example, Time diversity can be obtained through Coding or interleaving, and Space diversity can be obtained by placing a plurality of antennas at a transmitting end or a receiving end, for example, Multiple Input Multiple Output (MIMO) technology and Space Time Block Coding (STBC) technology can improve system capacity by times, and information can be transmitted under a better channel with higher probability, so that performance is improved.
Although the method can multiplex a plurality of user equipment in one beam through superposition of NOMA power domains, the method solves the interference problem among different beams and is a challenge, when the number of user equipment in a cell is large, the signaling overhead is large, and when the number of the user equipment in the cell is small, the efficiency is low.
In summary, in the related art, there is no effective solution for solving the problem that, when the multiple user equipment information NOMA is sent in a downlink, in an actual fading channel, if the information transmission encounters deep attenuation, the error code probability of the received information becomes large, and the terminal demodulates into the symbol-level SIC, so that there is a great risk of error propagation, which leads to the degradation of the access performance.
Disclosure of Invention
The embodiment of the invention provides a multi-antenna downlink data transmission method and equipment, which are beneficial to a terminal SIC to receive downlink data and improve the access performance and capacity of multi-user equipment under a downlink fading channel.
The embodiment of the invention provides a multi-antenna downlink data transmission method, which comprises the following steps:
forming an nth type optimized modulation symbol by the nth type data stream, wherein the value range of N is more than or equal to 1 and less than or equal to N, and N is an integer more than 1;
superposing the N types of optimized modulation symbols to obtain an M type symbol, wherein the value of M is equal to N + 1;
carrying out multi-antenna transmit diversity processing on the M-type symbol to form a transmit signal;
and sending the transmission signal.
The embodiment of the invention provides a multi-antenna downlink data transmission method, which comprises the following steps:
receiving a signal transmitted by a transmitter, wherein the signal is formed by superposing N types of optimized modulation symbols to obtain an M type symbol and performing multi-antenna transmit diversity processing on the M type symbol; wherein, the value of M is N +1, N is an integer greater than 1, and the transmitting signal passes through a fading channel;
balancing and detecting the symbols after the N types of optimized modulation symbols are superposed;
and demodulating a symbol corresponding to the user equipment according to a demodulation mode corresponding to the user equipment.
An embodiment of the present invention provides a transmitter, including:
the modulation unit is used for forming an nth type optimized modulation symbol for the nth type data stream, wherein the value range of N is more than or equal to 1 and less than or equal to N, and N is an integer more than 1;
the superposition unit is used for superposing the N types of optimized modulation symbols to obtain an M type symbol, and the value of M meets the requirement that M is equal to N + 1;
a transmit diversity processing unit, configured to perform multi-antenna transmit diversity processing on the mth type symbol to form a transmit signal;
and the transmitting unit is used for transmitting the transmitting signal.
An embodiment of the present invention provides a receiver, including:
the receiving unit is used for receiving a signal transmitted by a transmitter, wherein the signal is formed by superposing N types of optimized modulation symbols to obtain an M type symbol and performing multi-antenna transmit diversity processing on the M type symbol; wherein, M is N +1, N is an integer greater than 1, and the transmission signal passes through a fading channel;
the detection unit is used for detecting the superposed symbols of the N-type optimized modulation symbols in a balanced manner;
and the demodulation unit is used for demodulating the symbol corresponding to the user equipment according to the demodulation mode corresponding to the user equipment.
In the embodiment of the invention, after the modulation symbols of the multi-user equipment are optimized and superposed, the modulation symbols are processed by multi-antenna transmission diversity to form transmission signals which are sent by multiple antennas; therefore, when the receiving end receives signals from a plurality of antennas, the symbols which are superposed and coded by the sending end can be firstly demodulated through equalization, and then the information of the receiving end is demodulated according to a demodulation mode corresponding to the user equipment; the embodiment of the invention has the advantages that the multi-user equipment optimizes the symbols after superposition coding, is more beneficial to the reception of the terminal SIC, fully utilizes the diversity gain brought by multi-antenna transmission diversity and improves the access performance and capacity of the multi-user equipment under a downlink fading channel.
Drawings
Fig. 1 is a schematic flow chart illustrating a multi-antenna downlink data transmission method according to an embodiment of the present invention;
fig. 2 is a schematic flow chart of a multi-antenna downlink data transmission method according to an embodiment of the present invention;
fig. 3 shows a schematic diagram of a transmitter in an embodiment of the invention;
fig. 4 shows a schematic diagram of a receiver in an embodiment of the invention;
FIG. 5 is a schematic diagram of a wireless broadcast communication system implemented in accordance with and using the method of the present invention;
fig. 6 is a schematic diagram of a transmitter process for multi-antenna downlink data transmission according to an embodiment of the present invention and implemented using the method of the present invention;
fig. 7 is a schematic diagram of a receiver process for multi-antenna downlink data transmission according to an embodiment of the present invention and implemented using the method of the present invention;
fig. 8 is a schematic diagram of modulation symbol generation of two user equipments implemented according to and using the method of the present invention in the embodiment of the present invention;
figure 9 shows a diagram of a QPSK symbol-optimized superposition of two user equipments implemented in accordance with and using the method of the present invention in an embodiment of the present invention;
fig. 10 shows a schematic diagram of two-antenna diversity transmission and single-antenna reception implemented in accordance with and using the method of the present invention in an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
The embodiment of the present invention describes a multi-antenna downlink data transmission method, which implements data transmission, and as shown in fig. 1, includes:
And 102, superposing the N types of optimized modulation symbols to obtain an M type symbol, wherein the value of M is equal to M + 1.
And 104, sending the transmitting signal.
As an embodiment, the forming the nth type data stream into nth type optimized modulation symbols includes:
when n is 1, modulating the 1 st type data stream by adopting a1 st type optimized constellation to obtain a1 st type optimized modulation symbol; the constellation diagram formed by modulating all possible constellation points by the optimized constellation of the type 1 comprises: line segments and squares.
As an embodiment, the forming the nth type data stream into nth type optimized modulation symbols includes:
when N is 2 and N is 2, performing class 2 optimized constellation modulation on the class 2 data stream, and performing mirror image processing according to the class 1 optimized modulation symbol to obtain the class 2 optimized modulation symbol;
the constellation diagram formed by modulating all possible constellation points by the optimized constellation class 2 comprises: line segments, triangles, squares, rectangles and rhombuses; the class 2 optimized modulation symbols are related to the class 1 optimized modulation symbols; the type 2 data stream is formed into a type 2 optimized modulation symbol, and the following method can be adopted: the modulation symbol S1 optimized by the type 1 is represented as x1+ y1 · i, and the symbol S2 modulated by the optimized constellation of the type 2 is represented as x2+ y2 · i; and mirroring the symbol S2 according to the symbol S1 to obtain a type 2 optimized modulation symbol S, wherein the type 2 optimized modulation symbol S comprises one of the following:
the symbol S is
The symbol S is
Xstd, Ystd correspond to the unnormalized integer lattice constellation symbol S corresponding to symbol S1stdReal and imaginary parts of, SstdThe value is Xstd + Ystd.i;
meaning that the rounding is done down,
represents rounding up;
when the value of Xstd corresponding to Binary Phase Shift Keying (BPSK) is {1, -1}, the value of Ystd is zero; when the values of Xstd and Ystd corresponding to QPSK are {1, -1 }; the values of Xstd and Ystd corresponding to the 16 quadrature amplitude modulation QAM are {1, -1, 3, -3 }; the values of Xstd and Ystd corresponding to 64QAM are {1, -1, 3, -3, 5, -5, 7, -7 }.
As an embodiment, forming the nth type data stream into nth type optimized modulation symbols includes:
when N is larger than 1 and N is larger than 2, adopting the nth type optimized constellation modulation to the nth type data stream to obtain an nth type optimized modulation symbol; the constellation diagram formed by modulating all possible constellation points by the nth type of optimized constellation comprises: line segments, triangles, squares, rectangles, and diamonds.
The obtaining of the mth type symbol by superimposing the N types of optimized modulation symbols includes:
and when N is 2, superposing the 1 st type optimized modulation symbol and the 2 nd type optimized modulation symbol to obtain the M type symbol.
As an embodiment, the superimposing N types of optimized modulation symbols to obtain an M type symbol includes:
when N is more than 2, superposing the modulation symbol of the class 2 data stream to the modulation symbol of the class N data stream, and carrying out mirror image processing on the superposed symbols according to the class 1 optimized modulation symbol to obtain mirrored symbols;
and superposing the mirrored symbol and the type 1 optimized modulation symbol to obtain the M type symbol.
As an embodiment, the sending the transmission signal includes:
performing multi-antenna transmit diversity processing on the Mth class symbols corresponding to at least two moments, wherein the Mth class symbols correspond to the moments one to one;
transmitting the type 3 symbol by at least one of:
transmitting 1 or more copies in the time or frequency direction;
the transmission is switched in the time or frequency direction.
As an embodiment, the copy includes at least one of:
a class M symbol; variations of class M symbols; delaying the transmitted class M symbol.
The embodiment of the present invention further describes a multi-antenna downlink data transmission method, which implements data reception, and as shown in fig. 2, includes:
In one embodiment, the equalization detection is associated with a multi-antenna transmit diversity mode selected by the transmitter.
As an embodiment, the demodulation method includes:
directly demodulating the superposed symbols, wherein the superposed symbols carry interference of N-1 type data;
solving symbols with the strength higher than a threshold value in a received signal carrying interference of data different from the M-th type symbols, separating the symbols with the strength lower than the threshold value in the received signal by using a symbol level SIC to obtain signals, and carrying out mirror image processing on the obtained signals by using the symbols with the strength lower than the threshold value to solve the symbols;
wherein the mirror processing is consistent with the mirror processing mode of the transmitter.
An embodiment of the present invention describes a transmitter, which can be applied to a base station, as shown in fig. 3, including:
the modulation unit 31 is configured to form an nth optimized modulation symbol for an nth data stream, where N is an integer greater than or equal to 1 and is greater than or equal to N;
a superposition unit 32, configured to superpose the N-type optimized modulation symbols to obtain an M-th type symbol, where a value of M satisfies M ═ N + 1;
a transmit diversity processing unit 33, configured to perform multi-antenna transmit diversity processing on the mth type symbol to form a transmit signal;
a transmitting unit 34, configured to send the transmission signal.
As an embodiment, the modulation unit 31 is further configured to, when n is 1, modulate the class 1 data stream with a class 1 optimized constellation to obtain a class 1 optimized modulation symbol; the constellation diagram formed by modulating all possible constellation points by the optimized constellation of the type 1 comprises: line segments and squares.
As an embodiment, the modulation unit 31 is further configured to, when N is 2 and N is 2, modulate the class 2 data stream with the class 2 optimized constellation, and perform mirroring processing according to the class 1 optimized modulation symbol to obtain a class 2 optimized modulation symbol;
the constellation diagram formed by modulating all possible constellation points by the optimized constellation class 2 comprises: line segments, triangles, squares, rectangles and rhombuses;
the class 2 optimized modulation symbols are associated with the class 1 optimized modulation symbols.
As an embodiment, the modulation unit 31 is further configured to represent the type 1 optimized modulation symbol S1 as x1+ y1 · i, and represent the type 2 optimized constellation modulated symbol S2 as x2+ y2 · i;
and mirroring the symbol S2 according to the symbol S1 to obtain a type 2 optimized modulation symbol S, wherein the type 2 optimized modulation symbol S comprises one of the following:
the symbol S is
The symbol S is
Wherein Xstd and Ystd correspond to the unnormalized integer lattice constellation symbol S corresponding to the symbol S1stdXstd + Ystd · i being the non-normalized integer lattice constellation symbol S corresponding to said symbol S1std，
Meaning that the rounding is done down,
represents rounding up;
when the value of the Xstd corresponding to the BPSK is {1, -1}, the value of Ystd is zero; when the values of Xstd and Ystd corresponding to QPSK are {1, -1 }; the values of Xstd and Ystd corresponding to the 16 quadrature amplitude modulation QAM are {1, -1, 3, -3 }; the values of Xstd and Ystd corresponding to 64QAM are {1, -1, 3, -3, 5, -5, 7, -7 }.
As an embodiment, the modulation unit 31 is further configured to, when N > 1 and N > 2, perform nth-class optimized constellation modulation on an nth-class data stream to obtain an nth-class optimized modulation symbol; the constellation diagram formed by modulating all possible constellation points by the nth type of optimized constellation comprises: line segments, triangles, squares, rectangles, and diamonds.
The superimposing unit 32 is further configured to superimpose the type 1 optimized modulation symbol and the type 2 optimized modulation symbol when N is 2, so as to obtain the mth type symbol. .
As an embodiment, the transmitting unit 34 is further configured to perform multi-antenna transmit diversity processing on at least two mth type symbols, where the mth type symbols correspond to time instants one by one;
transmitting the type 3 symbol by one or a combination of:
transmitting 1 or more copies in the time or frequency direction;
the transmission is switched in the time or frequency direction.
As an embodiment, the copy includes at least one of:
the M-th class symbol; variations of class M symbols; delaying the transmitted M-th class symbol.
In practical application, the modulation unit 31, the superposition unit 32, and the transmit diversity processing unit 33 may be implemented by a Microprocessor (MCU) or a logic programmable gate array (FPGA); the transmitting unit 34 may be implemented as an antenna.
An embodiment of the present invention describes a receiver, which can be applied to a base station, and as shown in fig. 4, the receiver includes:
a receiving unit 41, configured to receive a signal transmitted by a transmitter, where the signal is formed after superimposing N-type optimized modulation symbols to obtain an M-type symbol, and performing multi-antenna transmit diversity processing on the M-type symbol (the number of the M-type symbols may be multiple); wherein, the value of M is N +1, N is an integer greater than 1, and the transmitting signal passes through a fading channel;
a detection unit 42, configured to detect a symbol obtained by superimposing the N types of optimized modulation symbols in an equalization manner;
the demodulating unit 43 is configured to demodulate a symbol corresponding to the user equipment according to a demodulation manner corresponding to the user equipment.
In one embodiment, the detecting unit 42 is configured to detect the multiple antenna transmit diversity mode selected by the transmitter in an equalization manner.
As an embodiment, the demodulation unit 43 is further configured to use the following demodulation method:
directly demodulating the superposed symbols, wherein the superposed symbols carry interference of N-1 type data;
resolving a symbol with the strength higher than a threshold value from the superposed symbols, separating the symbol with the strength lower than the threshold value from the received signals by using a symbol stage SIC to obtain a signal, and performing mirror image processing on the obtained signal by using the symbol with the strength lower than the threshold value to resolve the symbol;
wherein the mirror processing is consistent with the mirror processing mode of the transmitter.
In practical applications, the receiving unit 41 may be implemented by an antenna; the detection unit 42 and the demodulation unit 43 may be implemented by an MCU or an FPGA.
Fig. 5 shows a wireless broadcast communication system implemented in accordance with and using the method of the invention, the transmitter transmitting a plurality of data streams to a plurality of user equipments (in fig. 5 there are two user equipments, receiver 1 and receiver 2), receiver 1 being an edge user equipment and receiver 2 being a central user equipment, each user equipment extracting its own information from the received signal.
Fig. 6 is a schematic diagram of a transmitter processing for multi-antenna downlink data transmission, where information of a user equipment 1 is modulated by a class 1 optimized constellation to form a class 1 optimized modulation symbol, information of a user equipment 2 is modulated by a class 2 optimized constellation to form a class 2 optimized constellation modulated symbol, the class 2 optimized constellation modulated symbol is mirrored according to the class 1 optimized modulation symbol to form a class 2 optimized modulation symbol, the class 1 optimized modulation symbol and the class 2 optimized modulation symbol are superimposed to obtain a class 3 symbol, multiple class 3 symbols are subjected to multi-antenna transmit diversity processing, multiple symbols are engraved on the class 3 symbol at multiple times, and the class 3 symbol is transmitted by at least one of the following modes: transmitting 1 or more copies in the time or frequency direction; switching transmission in the time or frequency direction; wherein the copy comprises at least one of: a type 3 symbol; a variation of the type 3 symbol; delaying the transmitted type 3 symbol.
Fig. 7 is a schematic diagram of a receiver processing for multi-antenna downlink data transmission, which receives signals transmitted by a transmitter, superimposes the signals transmitted by the transmitter with N-type optimized modulation symbols to obtain M-type symbols, and performs multi-antenna transmit diversity processing on the M-type symbols to form a plurality of M-type symbols; the transmitted signal passes through a fading channel; m is N +1, N is an integer greater than 1;
secondly, symbols after the N types of optimized modulation symbols are superposed are detected in a balanced mode;
thirdly, demodulating and decoding the symbol of the corresponding user equipment according to a demodulation mode corresponding to the user equipment, for example, edge user equipment, and directly demodulating the received signal under the condition that the received signal has data interference which is different from the M-th symbol; if the signal is the central user equipment, SIC mirror image demodulation is carried out, namely, a symbol of the edge user equipment is demodulated under the condition that other types of data interference exist in a received signal, the symbol of the edge user equipment is separated by using a symbol level SIC, mirror image processing is carried out after the symbol of the edge user equipment is removed, and the symbol of the central user equipment is demodulated;
and decoding the demodulated symbols to obtain user equipment data.
The following description will be given by taking specific examples.
Example 1
The specific process of transmitting two pieces of user equipment information to two pieces of user equipment by the base station is to code and modulate the two pieces of user equipment information, allocate a certain power, optimize and superimpose modulation symbols of the user equipment, and as shown in fig. 8, a schematic diagram of generating modulation symbols of the two pieces of user equipment is shown.
Firstly, an information bit stream I1 provided for edge user equipment and an information bit stream I2 provided for center user equipment are respectively subjected to Turbo coding to obtain two user equipment information streams A1 and A2; the base station modulates the information flow of the edge user equipment and the information flow of the center user equipment A1 and A2 into a symbol of unit power according to the channel condition between the base station and the user equipment, and then distributes power P to the symbol of the edge user equipment1Obtaining modulation symbols S1 with certain power, distributing power P to central user equipment symbols2Obtaining a modulation symbol S2 with certain power; wherein P is1+P2Is equal to P, and P1>P2And P is the total power distributed by the base station to two user equipment.
Then, the optimal superposition of the modulation symbols of the user equipment is to superpose the modulation symbols of the center user equipment and the modulation symbols of the edge user equipment after mirroring the modulation symbols of the center user equipment according to the modulation symbols of the edge user equipment.
The constellation diagram formed by all possible constellation points of the modulation symbol of the edge user equipment comprises a line segment and a square; the constellation diagram formed by all possible constellation points of the modulation symbol of the central user equipment comprises a line segment, a triangle, a square, a rectangle and a rhombus.
The edge user device symbol S1 is denoted as x1+ y1 · i, the center user device symbol S2 is denoted as x2+ y2 · i; the method for obtaining the mirrored symbol S by mirroring the central user equipment symbol according to the edge user equipment symbol comprises the following steps: the symbol S after the mirror image is
The symbol S after the mirror image is
Wherein Xstd + Ystd.i is an unnormalized integer lattice point constellation symbol corresponding to the edge user equipment symbol,
meaning that the rounding is done down,
represents rounding up; non-normalized integer lattice constellation symbol SstdThe value is Xstd + Ystd · i, for example, the value of Xstd corresponding to BPSK is {1, -1}, the value of Ystd is zero, for example, the values of Xstd and Ystd corresponding to QPSK are {1, -1 }; the values of Xstd and Ystd corresponding to 16QAM Quadrature Amplitude Modulation (QAM) are {1, -1, 3, -3 }; the values of Xstd and Ystd corresponding to 64QAM are {1, -1, 3, -3, 5, -5, 7, -7 }.
The optimized superimposed complex symbol S3 can be represented as (S1+ S), or as
Can also be expressed as
As shown in fig. 9, which is a schematic diagram of QPSK symbol optimized superposition of two user equipments, first, when the symbol Xstd is-1 + i, i.e., Xstd is-1 and Ystd is 1, S is (-1) · x2+ y2 · i, which is equivalent to horizontally mirroring S2; after the mirroring step is completed, the subsequent step is to superpose S1 and S to obtain S3;
secondly, the multiple superposed symbols are subjected to multi-antenna transmit diversity processing, such as transmitting 1 or multiple copies in the time direction; the copy includes at least one of: a symbol after superposition; a variation form of the superimposed symbol;
the symbol set (corresponding to the M-th type symbol) after the k time-point optimized superposition is expressed as { g }kIs paired with { g) in the form of a matrixkAnd (4) performing two-antenna diversity processing:
set of symbols g at two time instants1，g2Take g as an example, let g1、g2And g1，g2The deformed symbols of (2) are arranged in a2 × 2 matrix in the above matrix form, and the row vectors of the matrix are orthogonal to each other, so that the symbol diversity processing at other times can be easily generalized.
Again, the diversity processed data is transmitted by two antennas. The symbols of each column being transmitted simultaneously by 2 antennas, e.g. by antenna 1 at time 1 g1G is transmitted by antenna 22At time 2, -g is transmitted by antenna 12 *G is transmitted by antenna 21 *(ii) a The transmission at other moments is easy to popularize;
as an example, g may also be paired in the form of a matrixkAnd 4, performing antenna diversity processing:
set of symbols g at 4 time instants1，g2，g3，g4As an example, gkFor complex symbols, g1，g2， g3，g4And g1，g2，g3，g4The above-described matrix form is arranged as a 4 × 4 matrix, and symbol diversity processing at other times is easily generalized.
Finally, the diversity processed data is transmitted by 4 antennas, and the symbols of each column are transmitted simultaneously by 4 antennas, for example, the 1 st time is transmitted by antenna 1 g1G is transmitted by antenna 22G is transmitted by the antenna 33G is transmitted by antenna 44(ii) a Transmission at other times is easily generalized.
As an example, g may also be paired in the form of a matrixkAnd 4, performing antenna diversity processing:
set of symbols g at 4 time instants1，g2，g3，g4As an example, gkFor real symbols, g1，g2，g3，g4And g1，g2，g3，g4The above-described matrix form is arranged as a 4 × 4 matrix, and symbol diversity processing at other times is easily generalized.
Finally, the symbols of each column are transmitted simultaneously by 4 antennas, e.g. antenna 1 transmits g at time 11G is transmitted by antenna 22G is transmitted by the antenna 33G is transmitted by antenna 44. Transmission at other times is easily generalized.
Through multi-antenna transmit diversity processing, each symbol or its deformed symbol is transmitted on different antennas, thereby fully utilizing diversity gain brought by multi-antenna transmit diversity, leveling reliability of the symbol, and obviously improving performance of symbol-level SIC under fading channel.
Example two
Fig. 10 is a schematic diagram of two ues after symbol-optimized superposition coding and then sent to a single-antenna receiver through two transmit antenna diversity processing.
The processing steps of the transmitter are consistent with example one, where the matrix selected is:
the processing of the receiver comprises:
firstly, receiving a transmitting signal from a transmitter at the 1 st moment and the 2 nd moment, wherein the transmitting signal is a transmitting signal formed by optimally superposing an edge user equipment modulation symbol and a center user equipment modulation symbol on the transmitter to obtain a superposed symbol and carrying out multi-antenna transmitting diversity processing on the superposed symbol; the transmitted signal passes through a fading channel h11，h21(ii) a At the 1 st moment of the receiver, the received signal is y1At time 2, the received signal is y2。
Then, equalizing and detecting the symbols after superposition coding of the multi-user equipment of the transmitter:
the equalization detection is related to the multi-antenna transmission diversity mode selected by the sending end;
finally, demodulating the symbol of the corresponding user equipment according to the demodulation mode corresponding to the user equipment; the edge user equipment directly carries the interference demodulation of the central user equipment; the central user equipment firstly solves the symbol of the edge user equipment with the interference of the edge user equipment, then separates the symbol of the edge user equipment in the received signal by using the symbol level SIC, removes the symbol of the edge user equipment and then carries out mirror image processing to solve the symbol of the central user equipment.
The mirroring process is consistent with the mirroring process of the transmitter in example one, and the mirrored symbols are related to the edge ue symbols solved first.
If the symbol obtained by removing the symbol of the edge user equipment in the received signal by the symbol stage SIC is x2 '+ y 2' · i, the mirroring process can be expressed as
Or
Wherein Xstd '+ Ystd' · i is the unnormalized integer lattice constellation symbol of the edge ue symbol solved first, if Xstd corresponding to BPSK takes {1, -1}, Ystd takes zero, if Xstd corresponding to QPSK, Ystd takes {1, -1},
meaning that the rounding is done down,
indicating rounding up.
In summary, in the embodiment of the present invention, the symbols after superposition coding are optimized by using multi-user equipment, which is more beneficial for receiving by the terminal SIC; and each symbol or the deformed symbol thereof is sent by different antennas, so that the diversity gain brought by multi-antenna transmission diversity is fully utilized, and the performance of the symbol-level SIC under a fading channel can be obviously improved.
Those of ordinary skill in the art will understand that: all or part of the steps for implementing the method embodiments may be implemented by hardware related to program instructions, and the program may be stored in a computer readable storage medium, and when executed, the program performs the steps including the method embodiments; and the aforementioned storage medium includes: various media that can store program codes, such as a removable Memory device, a Random Access Memory (RAM), a Read-Only Memory (ROM), a magnetic disk, and an optical disk.
Alternatively, the integrated unit of the present invention may be stored in a computer-readable storage medium if it is implemented in the form of a software functional module and sold or used as a separate product. Based on such understanding, the technical solutions of the embodiments of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the methods described in the embodiments of the present invention. And the aforementioned storage medium includes: a removable storage device, a RAM, a ROM, a magnetic or optical disk, or various other media that can store program code.
The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.
Claims (16)
1. A multi-antenna downlink data transmission method is characterized by comprising the following steps:
forming an nth type optimized modulation symbol by the nth type data stream, wherein the value range of N is more than or equal to 1 and less than or equal to N, and N is an integer more than 1;
superposing the N types of optimized modulation symbols to obtain an M type symbol, wherein the value of M is equal to N + 1;
carrying out multi-antenna transmit diversity processing on the M-type symbol to form a transmit signal;
transmitting the transmission signal;
wherein, the obtaining the M-th class symbol by superposing the N-class optimized modulation symbols includes:
when N is 2, superposing the 1 st type optimized modulation symbol and the 2 nd type optimized modulation symbol to obtain the M type symbol;
when N is more than 2, superposing the modulation symbol of the class 2 data stream to the modulation symbol of the class N data stream, and carrying out mirror image processing on the superposed symbols according to the class 1 optimized modulation symbol to obtain mirrored symbols; and superposing the mirrored symbol and the type 1 optimized modulation symbol to obtain the M type symbol.
2. The method of claim 1, wherein forming the class n data stream into class n optimized modulation symbols comprises:
when n is 1, modulating the 1 st type data stream by adopting a1 st type optimized constellation to obtain a1 st type optimized modulation symbol; the constellation diagram formed by modulating all possible constellation points by the optimized constellation of the type 1 comprises: line segments and squares.
3. The method of claim 1, wherein forming the class n data stream into class n optimized modulation symbols comprises:
when N is 2 and N is 2, performing class 2 optimized constellation modulation on the class 2 data stream, and performing mirror image processing according to the class 1 optimized modulation symbol to obtain a class 2 optimized modulation symbol;
the constellation diagram formed by modulating all possible constellation points by the optimized constellation class 2 comprises: line segments, triangles, squares, rectangles, and diamonds.
4. The method of claim 3, wherein the step of obtaining the type 2 optimized modulation symbol by performing the type 2 optimized constellation modulation on the type 2 data stream and performing mirror image processing according to the type 1 optimized modulation symbol comprises:
expressing the modulation symbol S1 optimized by the type 1 as x1+ y1 · i, and expressing the symbol S2 modulated by the type 2 optimized constellation as x2+ y2 · i;
performing the mirroring process on the symbol S2 according to the symbol S1 to obtain the type 2 optimized modulation symbol S, where the type 2 optimized modulation symbol S includes one of:
the symbol S is
The symbol S is
Wherein Xstd and Ystd correspond to the unnormalized integer lattice constellation symbol S corresponding to the symbol S1stdReal and imaginary parts of, SstdThe value is Xstd + Ystd.i;
meaning that the rounding is done down,
indicating rounding up.
5. The method of claim 1, wherein forming the class n data stream into class n optimized modulation symbols comprises:
when N is larger than 1 and N is larger than 2, adopting the nth type optimized constellation modulation to the nth type data stream to obtain an nth type optimized modulation symbol; the constellation diagram formed by modulating all possible constellation points by the nth type of optimized constellation comprises: line segments, triangles, squares, rectangles, and diamonds.
6. The method of claim 1, wherein the subjecting the plurality of mth type symbols to multi-antenna transmit diversity processing to form a transmit signal comprises:
performing multi-antenna transmit diversity processing on the Mth class symbols corresponding to at least two moments, wherein the Mth class symbols correspond to the moments one to one;
transmitting the M-th class symbol by combining at least one of:
transmitting 1 or more copies in the time or frequency direction;
the transmission is switched in the time or frequency direction.
7. The method of claim 6, wherein the replica includes at least one of:
the M-th class symbol; a variation of the class M symbol; delaying the transmitted M-th class symbol.
8. A multi-antenna downlink data transmission method is characterized by comprising the following steps:
receiving a signal transmitted by a transmitter, wherein the signal is formed by superposing N types of optimized modulation symbols to obtain an M type symbol and performing multi-antenna transmit diversity processing on the M type symbol; wherein, the value of M is N +1, N is an integer greater than 1, and the transmitting signal passes through a fading channel;
balancing and detecting the symbols after the N types of optimized modulation symbols are superposed;
demodulating a symbol corresponding to the user equipment according to a demodulation mode corresponding to the user equipment;
wherein, the demodulation mode comprises:
directly demodulating the superposed symbols, wherein the superposed symbols carry interference of N-1 type data;
resolving a symbol with the strength higher than a threshold value from the superposed symbols, separating the symbol with the strength lower than the threshold value from the received signal by using a symbol-level Serial Interference Cancellation (SIC) to obtain a signal, and performing mirror image processing on the obtained signal by using the symbol with the strength lower than the threshold value to resolve the symbol; the mirror processing is in accordance with the mirror processing mode of the transmitter.
9. A transmitter, comprising:
the modulation unit is used for forming an nth type optimized modulation symbol for the nth type data stream, wherein the value range of N is more than or equal to 1 and less than or equal to N, and N is an integer more than 1;
the superposition unit is used for superposing the N types of optimized modulation symbols to obtain an M type symbol, and the value of M meets the requirement that M is equal to N + 1;
a transmit diversity processing unit, configured to perform multi-antenna transmit diversity processing on the mth type symbol to form a transmit signal;
a transmitting unit for transmitting the transmission signal;
the superposition unit is further configured to superpose the type 1 optimized modulation symbol and the type 2 optimized modulation symbol when N is 2, so as to obtain the M-th type symbol; and when N is larger than 2, superposing the modulation symbol of the class 2 data stream to the modulation symbol of the class N data stream, carrying out mirror image processing on the superposed symbol according to the class 1 optimized modulation symbol to obtain a mirrored symbol, and superposing the mirrored symbol and the class 1 optimized modulation symbol to obtain the class M symbol.
10. The transmitter of claim 9,
the modulation unit is further configured to, when n is 1, modulate the class 1 data stream with a class 1 optimized constellation to obtain a class 1 optimized modulation symbol; the constellation diagram formed by modulating all possible constellation points by the optimized constellation of the type 1 comprises: line segments and squares.
11. The transmitter of claim 9,
the modulation unit is further configured to, when N is 2 and N is 2, modulate the class 2 data stream with a class 2 optimized constellation, and perform mirroring processing according to the class 1 optimized modulation symbol to obtain the class 2 optimized modulation symbol;
the constellation diagram formed by modulating all possible constellation points by the optimized constellation class 2 comprises: line segments, triangles, squares, rectangles, and diamonds.
12. The transmitter of claim 11,
the modulation unit is further configured to represent the optimized modulation symbol S1 of the type 1 as x1+ y1 · i, and represent the symbol S2 modulated by the optimized constellation of the type 2 as x2+ y2 · i;
performing the mirroring process on the symbol S2 according to the symbol S1 to obtain the type 2 optimized modulation symbol S, where the type 2 optimized modulation symbol S includes one of:
the symbol S is
The symbol S is
Wherein Xstd and Ystd are the real part and imaginary part of the unnormalized integer lattice constellation symbol Sstd corresponding to the symbol S1, SstdThe value is Xstd + Ystd.i;
meaning that the rounding is done down,
indicating rounding up.
13. The transmitter of claim 9,
the modulation unit is further configured to, when N is greater than 1 and N is greater than 2, modulate the nth type of data stream with an nth type of optimized constellation to obtain an nth type of optimized modulation symbol; the constellation diagram formed by modulating all possible constellation points by the nth type of optimized constellation comprises: line segments, triangles, squares, rectangles, and diamonds.
14. The transmitter of claim 9,
the transmitting unit is further configured to perform multi-antenna transmit diversity processing on the mth type symbols corresponding to at least two moments, where the mth type symbols correspond to the moments one to one;
transmitting the M-th class symbol by combining at least one of:
transmitting 1 or more copies in the time or frequency direction;
the transmission is switched in the time or frequency direction.
15. The transmitter of claim 14, wherein the replica comprises at least one of:
the M-th class symbol; a variation of the class M symbol; delaying the transmitted M-th class symbol.
16. A receiver, comprising:
the receiving unit is used for receiving a signal transmitted by a transmitter, wherein the signal is formed by superposing N types of optimized modulation symbols to obtain an M type symbol and performing multi-antenna transmit diversity processing on the M type symbol; wherein, M is N +1, N is an integer greater than 1, and the transmission signal passes through a fading channel;
the detection unit is used for detecting the superposed symbols of the N-type optimized modulation symbols in a balanced manner;
the demodulation unit is used for demodulating a symbol corresponding to the user equipment according to a demodulation mode corresponding to the user equipment;
wherein the demodulation unit is further configured to use the following demodulation scheme:
directly demodulating the superposed symbols, wherein the superposed symbols carry interference of N-1 type data;
resolving a symbol with the strength higher than a threshold value from the superposed symbols, separating the symbol with the strength lower than the threshold value from the received signal by using a symbol-level Serial Interference Cancellation (SIC) to obtain a signal, and performing mirror image processing on the obtained signal by using the symbol with the strength lower than the threshold value to resolve the symbol; the mirror processing is in accordance with the mirror processing mode of the transmitter.
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| CN201410837075.5A CN105790816B (en) | 2014-12-26 | 2014-12-26 | Multi-antenna downlink data transmission method and equipment |
| PCT/CN2015/084381 WO2016101601A1 (en) | 2014-12-26 | 2015-07-17 | Multi-antenna downlink data transmission method and device, and computer storage medium |
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| CN101471757A (en) * | 2007-12-25 | 2009-07-01 | 华为技术有限公司 | Receive coalition method, system and equipment |
| CN101656560A (en) * | 2009-09-24 | 2010-02-24 | 北京理工大学 | Collaboration communication method of high-efficiency frequency spectrum utilization ratio |
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| CN101447854A (en) * | 2007-11-27 | 2009-06-03 | 上海华为技术有限公司 | Data transmission/forwarding/processing method and device thereof |
| CN101471757A (en) * | 2007-12-25 | 2009-07-01 | 华为技术有限公司 | Receive coalition method, system and equipment |
| CN101656560A (en) * | 2009-09-24 | 2010-02-24 | 北京理工大学 | Collaboration communication method of high-efficiency frequency spectrum utilization ratio |
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