CN108365875B - Method for reducing PAPR (peak to average power ratio) of multiple antennas based on precoding and MIMO (multiple input multiple output) system - Google Patents
Method for reducing PAPR (peak to average power ratio) of multiple antennas based on precoding and MIMO (multiple input multiple output) system Download PDFInfo
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- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
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- H04—ELECTRIC COMMUNICATION TECHNIQUE
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- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
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Abstract
The invention provides a method for reducing PAPR of multiple antennas based on precoding and an MIMO system, wherein the method comprises the following steps: providing a useful signal data stream and N randomly generated virtual signal data streams; mapping the N groups of virtual signal data streams and the useful signal data streams onto a transmitting antenna through precoding to obtain N groups of pre-transmitting signals; performing inverse fast Fourier transform on the N groups of pre-transmission signals; and calculating the PAPR of each group of pre-transmitted signals, comparing the PAPRs, and selecting one group of pre-transmitted signals with the minimum PAPR from the N groups of pre-transmitted signals to transmit. The invention uses the idea of eliminating the interference between users by the precoding technology in the multi-user MIMO for reference, the virtual data stream is regarded as other user signals, and the receiving end only receives useful signals through the precoding technology.
Description
Technical Field
The invention relates to the technical field of wireless communication, in particular to a method for reducing PAPR (peak-to-average power ratio) of multiple antennas based on precoding and an MIMO (multiple input multiple output) system.
Background
The MIMO (Multiple-Input Multiple-Output) technology is to improve communication quality by using a plurality of transmitting antennas and receiving antennas at a transmitting end and a receiving end, respectively, and transmitting and receiving signals through the plurality of antennas at the transmitting end and the receiving end. The multi-antenna multi-transmission multi-reception system can fully utilize space resources, realizes multi-transmission and multi-reception through a plurality of antennas, can improve the system channel capacity by times under the condition of not increasing frequency spectrum resources and antenna transmitting power, shows obvious advantages and gradually becomes a core technology of mobile communication.
Orthogonal Frequency Division Multiplexing (OFDM) technology can achieve very high data transmission rate, and its modulation and demodulation are respectively realized based on Inverse Fast Fourier Transform (IFFT) and Fast Fourier Transform (FFT), which is a multicarrier transmission scheme with the lowest complexity and the most application. However, since the OFDM symbol is formed by superimposing a plurality of independently modulated subcarrier signals, when the phases of the respective subcarriers are the same or close to each other, the superimposed signal is modulated by the same initial phase signal, so that a large instantaneous power peak is generated, thereby further leading to a high peak-to-average power ratio (PAPR). When non-linear elements such as a power amplifier and a mixer are encountered in a transmission process, because the dynamic range of a general power amplifier is limited, a MIMO-OFDM signal with a large peak-to-average ratio is easy to enter a non-linear region of the power amplifier, so that the signal generates non-linear distortion, which causes obvious spectrum spreading interference and in-band signal distortion, and the performance of the whole system is seriously reduced. More power back-off is then required to bring the signal power back into the linear range of the power amplifier, which necessarily results in lower power efficiency. High peak-to-average ratio has become a major technical obstacle for MIMO-OFDM. Therefore, there is a need to develop PAPR reduction techniques to reduce cost and improve power efficiency of communication systems.
The specific definition of PAPR on the ith transmit antenna is:
wherein x isl(N) is the transmitted signal on the ith transmit antenna, N is the total number of subcarriers in the OFDM signal, and E (-) indicates the expectation.
Since there are multiple antennas in the MIMO system, the system PAPR is defined as:
where L is the number of transmit antennas.
Aiming at the problem of high PAPR, at present, there are many technical schemes for inhibiting PAPR, which are mainly divided into the following two categories:
1. lossy PAPR suppression techniques. Mainly includes clipping, filtering clipping technique, which is used to limit the signal amplitude, but this will result in signal distortion and loss of system performance;
2. lossless PAPR suppression techniques. Some of the technologies require a sending end to transmit extra information and to modify an existing communication system, while others have a lower data transmission rate compared with the conventional OFDM, and all of the technologies require extra computing resources to execute.
An invention of the university of electronic technology, application number CN201410268749.4, discloses a PTS method for reducing PAPR of MIMO-OFDM system, source bits are modulated by baseband, converted from serial to parallel, and then divided into subblocks, time domain subblock signals are obtained by IFFT modulation, phase change is realized by cyclic shift of subblocks of different lengths, and more alternative sequences are obtained by subblock exchange between antennas, more alternative sequence sets can be obtained under the same IFFT modulation number, and blind detection of received signals is realized by comparing distances between reverse rotation signals and signal constellation points. However, this blind detection method is computationally complex.
The invention discloses a method for reducing PAPR of an MIMO-OFDM system, which is disclosed by the invention with the application number of CN201410031169.3 of Zhejiang university, and the method comprises the steps of grouping antennas in pairs, carrying out spatial domain freedom degree expansion on each group of antenna data to obtain a relatively better to-be-transmitted sequence, applying SLM technology in a frequency domain to obtain a data sequence with the optimal current performance for transmission, mapping out a phase sequence on one antenna and a phase sequence meeting an orthogonal relation on the matched antenna, and reducing the calculated amount and the sideband information amount of a traditional calculation method. However, this method still needs to transmit the amount of sideband information to the receiving end, and faces the problems of information loss and increased transmission cost during channel transmission.
Disclosure of Invention
In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a method for reducing PAPR of multiple antennas based on precoding and a MIMO system, so as to solve the problem that system performance is affected due to high PAPR in the MIMO-OFDM system.
In order to achieve the purpose, the invention adopts the following scheme: a method for reducing PAPR of multiple antennas based on precoding, the method comprising the steps of: step 1), providing useful signal data streams and N groups of randomly generated virtual signal data streams, wherein N is a positive integer greater than or equal to 2; step 2), mapping the N groups of virtual signal data streams and the useful signal data streams onto a transmitting antenna through precoding to obtain N groups of pre-transmitting signals; step 3), performing inverse fast Fourier transform on the N groups of pre-transmitted signals; and 4), calculating the PAPR of each group of pre-transmitted signals, comparing, and selecting one group of pre-transmitted signals with the minimum PAPR in the N groups of pre-transmitted signals to transmit.
In an embodiment of the present invention, the step 1) further includes modulating the useful signal data stream and the N groups of dummy signal data streams by a quadrature amplitude modulation method or a quadrature phase shift keying modulation method.
In an embodiment of the present invention, in the step 1), the N groups of virtual signal data streams are randomly generated by a monte-carlo method.
In an embodiment of the present invention, in the step 2), the power of the useful signal data stream and the power of the virtual signal data stream are normalized, so as to obtain a ratio of the power of the useful signal data stream to the power of the virtual data stream.
In an embodiment of the present invention, the precoding matrix used in the precoding is a block diagonalized precoding matrix.
In an embodiment of the present invention, the precoding matrix satisfies the following condition: q (k) ═ Q1(k),Q2(k)]，H(k)Q2(k)＝H2(k)Q1(k) 0, where Q (k) is a precoding matrix, Q1(k) Is a pre-coding matrix, Q, of the data stream of the useful signal2(k) Is the number of virtual signalsPrecoding matrix of data stream, H2(k) H (k) is known channel state information for the transmitting end to the virtual receiving end.
In an embodiment of the present invention, the precoding-based method for reducing PAPR of multiple antennas is applicable to multiple user MIMO scenarios and large-scale MIMO scenarios.
The invention also provides a MIMO system for reducing PAPR of multiple antennas based on precoding, the MIMO system comprises a sending end and a receiving end, the sending end at least comprises: a signal modulator, receiving useful signal data streams with different powers and virtual signal data streams with different powers, and being suitable for modulating the useful signal data streams and the virtual signal data streams; the input end of the pre-coding module is connected with the output end of the signal modulator and is suitable for pre-coding the modulated signal data stream and the modulated virtual signal data stream to obtain a plurality of pre-transmitting signals, wherein the number of the pre-transmitting signals is consistent with that of the virtual signal data stream; the input end of the inverse Fourier transform module is connected with the output end of the pre-coding module and is suitable for performing inverse Fourier transform on each pre-transmitted signal; the input end of the power amplifier is connected with the output end of the inverse Fourier transform module and is suitable for performing power amplification on an output signal of the inverse Fourier transform module; and the input end of the transmitting antenna is connected with the output end of the power amplifier and is suitable for wirelessly transmitting the output signal of the power amplifier.
In an embodiment of the present invention, the MIMO system further includes a random signal generating module for generating a virtual signal data stream, and an output terminal of the random signal generating module is connected to an input terminal of the signal modulator.
In an embodiment of the present invention, the signal modulator is a quadrature amplitude modulator or a quadrature phase shift keying modulator.
In an embodiment of the present invention, the precoding matrix adopted in the precoding module is a block diagonalization precoding matrix.
In an embodiment of the present invention, the multi-antenna receiving end includes: the receiving antenna is used for receiving the transmitting signal sent by the transmitting end; the input end of the Fourier transform module is connected with the output end of the receiving antenna and is suitable for carrying out Fourier transform on the received signal; the input end of the detector is connected with the output end of the Fourier transform module and is suitable for detecting and separating the signals output by the Fourier transform module to obtain the useful signal data stream and the virtual signal data stream; a signal demodulator, an input of which is connected to an output of the detector, adapted to demodulate the data stream of useful signals.
As described above, the method for reducing PAPR of multiple antennas based on precoding and MIMO system of the present invention use the idea of eliminating inter-user interference by precoding technology in multi-user MIMO, and consider the virtual signal data stream as other user signals, so that the receiving end only receives useful signals through precoding technology. Has the following beneficial effects:
1) in an MIMO system, the method can reduce the PAPR value about 1-2 dB, effectively reduce the peak-to-average power ratio of the system and improve the system performance;
2) compared with other methods for reducing the PAPR, the method does not change the system structure, does not need extra overhead of a receiving end, and saves the cost.
Drawings
Fig. 1 is a flowchart illustrating a method for reducing PAPR of multiple antennas based on precoding according to a first embodiment of the present invention.
FIG. 2 is a CCDF curve of a transmitted signal in a first embodiment of the method for reducing PAPR of multiple antennas based on precoding according to the present invention
FIG. 3 is a CCDF curve of a transmitted signal in the second embodiment of the method for reducing PAPR of multiple antennas based on precoding according to the present invention
Fig. 4 is a structural diagram of a transmitting end in a MIMO system for reducing PAPR of multiple antennas based on precoding according to a third embodiment of the present invention.
Fig. 5 is a structural diagram of a receiving end in a MIMO system for reducing PAPR of multiple antennas based on precoding according to a third embodiment of the present invention.
Description of the element reference numerals
1 sending terminal
11 signal modulator
12 precoding module
13 inverse Fourier transform module
14 power amplifier
15 transmitting antenna
16 random signal generating module
2 receiving end
21 receiving antenna
22 Fourier transform module
23 Detector
24 signal demodulator
S1-S4
Detailed Description
The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention. It is to be noted that the features in the following embodiments and examples may be combined with each other without conflict.
It should be noted that the drawings provided in the following embodiments are only for illustrating the basic idea of the present invention, and although the drawings only show the components related to the present invention and are not drawn according to the number, shape and size of the components in the actual implementation, the type, amount and ratio of the components in the actual implementation may be changed arbitrarily, and the layout of the components may be complicated.
Example one
Referring to fig. 1, the present invention provides a method for reducing PAPR of multiple antennas based on precoding, which is suitable for multi-user MIMO scenarios and massive MIMO scenarios, and the method at least includes the following steps:
step 1), providing useful signal data streams and N groups of randomly generated virtual signal data streams, wherein N is a positive integer greater than or equal to 2;
step 2), mapping the N groups of virtual signal data streams and the useful signal data streams onto a transmitting antenna through precoding to obtain N groups of pre-transmitting signals;
step 3), performing inverse fast Fourier transform on the N groups of pre-transmitted signals;
and 4), calculating the PAPR of each group of pre-transmitted signals, comparing the PAPRs, and selecting one group of pre-transmitted signals with the minimum PAPR from the N groups of pre-transmitted signals to transmit.
As an example, a MIMO system is configured to have L transmitting antennas at a transmitting end and N receiving antennas at a receiving end. Let S (k) be [ S ]1(k),S2(k),…,SM(k)]TFor useful signal data streams, V (k) ═ V1(k),V2(k),…,VP(k)]TIs a virtual signal data stream, where the virtual signal data stream v (k) can be regarded as other user signals in multi-user MIMO for adjusting the power peak of the transmitted signal.
As an example, in the step 1), the useful signal data stream s (k) and the dummy signal data stream v (k) are first modulated by a quadrature amplitude modulation or quadrature phase shift keying modulation method.
It should be noted that, in step 2) of the present invention, by taking the idea of eliminating inter-user interference by using a precoding technique in multi-user MIMO as a reference, the virtual signal data stream is regarded as other user signals, and the inter-user interference is eliminated by using the precoding technique, so that the receiving end only receives the useful signal data stream.
In step 2), normalizing the power of each data stream to obtain a ratio of the power M of the useful signal data stream to the power P of the virtual signal data stream.
For example, if the precoding matrix is q (k), the transmission signal is x (k) ═ q (k) [ s (k), v (k)]T. In the step 3), Discrete Fourier Transform (DFT) and Inverse Discrete Fourier Transform (IDFT) operations are respectively implemented using FFT and IFFT. Each group of virtual signal data streams can obtain a group of corresponding transmitting signals X (k), and each group of transmitting signals is subjected to IFFT operation.
In the step 4), the PAPR of each group of pre-transmitted signals is calculated and compared, and one group of pre-transmitted signals with the smallest PAPR among the N groups of pre-transmitted signals is selected for transmission.
It should be further explained that, the present invention eliminates the influence of the virtual signal data stream on the receiving end through the precoding technology, the receiving end can receive the useful signal without any structural change, and effectively reduces the PAPR value of the system and improves the performance of the system while not being interfered by the virtual signal data stream, wherein the process of transmitting the transmission signal from the channel to the receiving end for receiving and detecting is specifically described as follows:
the known channel state information is h (k), which is a channel response between L transmitting antennas and N receiving antennas at the receiving end, and is regarded as the channel state information between the useful signal and the receiving end. Considering the idea of handling multi-user interference in multi-user MIMO, a virtual data stream is regarded as other user signals that are not received by a receiving end, and it is assumed that channel state information from a transmitting end to a virtual receiving end is H2(k) In that respect When the equivalent channel state information is
Deriving a precoding matrix Q (k) ═ Q using a precoding technique based on the above information1(k),Q2(k)]Wherein Q is1(k) Is a precoding matrix, Q, of the data stream of the useful signal2(k) Is the precoding matrix for the virtual data stream. Need to satisfy H (k) Q2(k)＝H2(k)Q1(k) 0. Wherein H2(k) Can be fixed as a certain oneConstant value, no change required in a short time, thereby determining Q1(k) The method can also be regarded as constant use, and the receiving end can be used after being known, so that no extra overhead is needed. The received signal at the receiving end is
Wherein, w (k) is white gaussian noise, and the useful signal data stream s (k) can be recovered by signal detection.
Through the analysis, the additional virtual signal data stream is added at the transmitting end, the power peak value of the transmitting signal is reduced, and the receiving end cannot receive the virtual data stream which affects the system performance. Therefore, the purposes of reducing the PAPR without increasing the receiving end overhead are achieved.
The Complementary Cumulative Distribution Function (Complementary Cumulative Distribution Function) is a concept introduced to represent the statistical property of peak-to-average PAPR in OFDM systems, and is defined as the probability of peak-to-average value exceeding a certain threshold in a multi-carrier transmission system. The effect of reducing PAPR in the present invention is described below with reference to the CCDF curve.
In the MIMO system, L is set to be 6 transmitting antennas at a transmitting end, and N is set to be 4 receiving antennas at a receiving end. The useful signal data stream is M ═ 4, the dummy signal data stream P ═ 1, and the ratio of the power of the useful signal data stream to the power of the dummy data stream is
The present example modulates the useful signal data stream and the dummy signal data stream using a QPSK (Quadrature Phase Shift key modulation) scheme. An OFDM system with 256 total subcarriers modulates a transmission signal. Knowing the channel state information H (k), randomly generating H2(k) The Block Diagonalization (BD) precoding matrix technique is used to generate a precoding matrix to eliminate the interference of the virtual signal data stream. Obtaining 16 different groups of virtual signal data streams V by Monte Carlo methodb(k) B is more than or equal to 1 and less than or equal to 16. 16 different sets of transmission signalsXb(k) The PAPRs of the 16 groups of transmitted signals are compared through an IFFT module, and the smallest of the PAPRs is selected as the transmitted signal.
FIG. 2 shows a ratio of power for a desired signal data stream to power for a dummy signal data stream
A graph of the complementary cumulative distribution function CCDF is drawn in the case of (a), where the solid line is the CCDF curve of the transmitted signal with the original unadded virtual signal datastream and the dashed line is the CCDF curve of the transmitted signal after using the method of the present invention. As can be seen from fig. 2, the PAPR of the method of the present invention is reduced by about 1 dB. And under the condition that the receiving end does not increase any extra overhead, the sending end is not required to send extra related information.
Example two
This embodiment differs from the first embodiment only in that the ratio of the power of the useful signal data stream to the power of the dummy data stream is
Other steps are consistent with the embodiments and are not described herein.
FIG. 3 is a graph of the ratio of the power of a desired signal data stream to the power of a dummy signal data stream
The solid line is the CCDF curve for the transmitted signal with the original virtual signal data stream not added, and the dashed line is the CCDF curve for the transmitted signal after the method of this patent is used. As can be seen from fig. 3, the PAPR of the present invention is reduced by about 2 dB. And under the condition that the receiving end does not increase any extra overhead, the sending end is not required to send extra related information.
EXAMPLE III
The present invention further provides a MIMO system for reducing PAPR of multiple antennas based on precoding, where the MIMO system includes a transmitting end 1 and a receiving end 2, and referring to fig. 4, the transmitting end 1 at least includes: a signal modulator 11, receiving useful signal data streams with different powers and virtual signal data streams with different powers, and adapted to modulate the useful signal data streams and the virtual signal data streams; a pre-coding module 12, an input end of the pre-coding module 12 is connected to an output end of the signal modulator 11, and is adapted to pre-code the modulated signal data stream and the modulated virtual signal data stream to obtain a plurality of pre-transmission signals, wherein the number of the pre-transmission signals is consistent with the number of the virtual signal data streams; an inverse fourier transform module 13, an input end of the inverse fourier transform module 13 being connected to an output end of the precoding module 12, and being adapted to perform inverse fourier transform on each pre-transmission signal respectively; the input end of the power amplifier 14 is connected with the output end of the inverse fourier transform module 13, and is adapted to perform power amplification on the output signal of the inverse fourier transform module; and the input end of the transmitting antenna 15 is connected with the output end of the power amplifier 14, and the transmitting antenna 15 is suitable for wirelessly transmitting the output signal of the power amplifier.
In addition, S (k) ═ S1(k),S2(k),…,SM(k)]TFor useful signal data streams, V (k) ═ V1(k),V2(k),…,VP(k)]TFor the virtual signal data stream, in FIG. 4, S1……SMCorresponds to S1(k),S2(k),…,SM(k) Wherein, M refers to the Mth row and the kth column in the S (k) matrix; v1……VPCorresponds to V1(k),V2(k),…,VP(k) Wherein, P refers to the P row and the k column in the V (k) matrix; x1……XLThe signals are a plurality of groups of pre-transmitted signals after pre-coding; x is the number of1……xLThe signals are a plurality of groups of pre-sent signals after Fourier inverse transformation; y is1……yLThe group of pre-transmitted signals with the smallest PAPR value selected from the plurality of groups of pre-transmitted signals is used as the final transmitted signal.
As an example, the MIMO system further includes a random signal generating module 16 for generating a virtual signal data stream, and an output terminal of the random signal generating module 16 is connected to an input terminal of the signal modulator 11.
The signal modulator 11 is, as an example, a quadrature amplitude modulator or a quadrature phase shift keying modulator.
As an example, the precoding matrix employed in the precoding module 12 is a block diagonalized precoding matrix.
As an example, referring to fig. 5, the multi-antenna receiving end 2 includes: a receiving antenna 21, where the receiving antenna 21 is configured to receive a transmission signal sent by the sending end 1; a fourier transform module 22, an input end of the fourier transform module 22 is connected to an output end of the receiving antenna 21, and is adapted to perform fourier transform on the received signal; the input end of the detector 23 is connected with the output end of the Fourier transform module 22, and the detector 23 is suitable for detecting and separating the signals output by the Fourier transform module; a signal demodulator 24, an input of said signal demodulator 24 being connected to an output of said detector 23, adapted to demodulate said wanted-signal data stream from subcarriers.
In FIG. 5, r1……rNFor signals received by the receiver 2, R1……RNIs a Fourier transformed signal, S'1……S’MThe modulated signal is recovered by a demodulator for the desired signal data stream recovered after passing through the signal detector 23.
For the multi-antenna receiving end 2, no structural change is made, and the useful signal data stream can be received without increasing the additional overhead of the receiving end 2, so that the MIMO system for reducing the PAPR of the multi-antenna based on precoding effectively reduces the peak-to-average ratio of the system and improves the performance of the system; compared with other methods for reducing the PAPR, the method does not change the system structure and saves the cost.
In summary, the method for reducing PAPR of multiple antennas based on precoding and MIMO system of the present invention use the idea of eliminating interference between users by precoding technology in multi-user MIMO to consider the virtual signal data stream as other user signals, and enable the receiving end to receive only useful signals by precoding technology. In an MIMO system, the method can reduce the PAPR value by about 1-2 dB, effectively reduce the peak-to-average ratio of the system and improve the system performance; compared with other methods for reducing the PAPR, the method does not change the system structure, does not need extra overhead of a receiving end, and saves the cost. Therefore, the invention effectively overcomes various defects in the prior art and has high industrial utilization value.
The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which may be accomplished by those skilled in the art without departing from the spirit and scope of the present invention as set forth in the appended claims.
Claims (10)
1. A method for reducing a peak-to-average power ratio (PAPR) of multiple antennas based on precoding, the method comprising at least the steps of:
step 1), providing useful signal data streams and N groups of randomly generated virtual signal data streams, wherein N is a positive integer greater than or equal to 2;
step 2), mapping the N groups of virtual signal data streams and the useful signal data streams onto a transmitting antenna through precoding to obtain N groups of pre-transmitting signals; the precoding matrix adopted in the precoding is a block diagonalization precoding matrix; the precoding matrix satisfies the condition: q (k) ═ Q1(k)，Q2(k)]，H(k)Q2(k)＝H2(k)Q1(k) 0, where Q (k) is a precoding matrix, Q1(k) Is a precoding matrix, Q, of the data stream of the useful signal2(k) Is a precoding matrix for the virtual signal data stream, H2(k) H (k) is channel state information from the transmitting end to the user receiving end;
step 3), performing inverse fast Fourier transform on the N groups of pre-transmitted signals;
and 4), calculating the PAPR of each group of pre-transmitted signals, comparing the PAPRs, and selecting one group of pre-transmitted signals with the minimum PAPR from the N groups of pre-transmitted signals to transmit.
2. The precoding-based multi-antenna PAPR reduction method according to claim 1, further comprising modulating the wanted signal data streams and the N sets of dummy signal data streams by quadrature amplitude modulation or quadrature phase shift keying modulation method in the step 1).
3. The precoding-based multi-antenna PAPR reduction method according to claim 2, wherein in the step 1), the N sets of virtual signal data streams are randomly generated by a monte-carlo method.
4. The method for reducing PAPR based on precoding according to claim 1, wherein in step 2), the method further comprises normalizing the power of the desired signal data stream and the power of the virtual signal data stream to obtain the ratio of the power of the desired signal data stream to the power of the virtual signal data stream.
5. The method for reducing PAPR based on precoding according to any of claims 1-4, wherein the method for reducing PAPR based on precoding is applicable to scenarios including multi-user MIMO scenario and massive MIMO scenario.
6. A MIMO system for reducing PAPR of multiple antennas based on precoding, the MIMO system includes a transmitting end and a receiving end, the transmitting end at least includes:
the signal modulator receives useful signal data streams with different powers and virtual signal data streams with different powers, and is suitable for modulating the useful signal data streams and the virtual signal data streams;
a pre-coding module, an input end of the pre-coding module is connected with an output end of the signal modulator, and is suitable for pre-coding the modulated useful signal data stream and the modulated virtual signal data stream to obtain a plurality of pre-transmission signals, wherein the pre-transmission signals are obtainedThe number of the pre-transmission signals is consistent with the number of the virtual signal data streams; the precoding matrix adopted in the precoding module is a block diagonalization precoding matrix; the precoding matrix satisfies the condition: q (k) ═ Q1(k)，Q2(k)]，H(k)Q2(k)＝H2(k)Q1(k) 0, where Q (k) is a precoding matrix, Q1(k) Is a precoding matrix, Q, of the data stream of the useful signal2(k) Is a precoding matrix for the virtual signal data stream, H2(k) H (k) is channel state information from the transmitting end to the user receiving end;
the input end of the inverse Fourier transform module is connected with the output end of the pre-coding module and is suitable for performing inverse Fourier transform on each pre-transmitted signal;
the input end of the power amplifier is connected with the output end of the inverse Fourier transform module and is suitable for performing power amplification on an output signal of the inverse Fourier transform module;
and the input end of the transmitting antenna is connected with the output end of the power amplifier and is suitable for wirelessly transmitting the output signal of the power amplifier.
7. The MIMO system for reducing PAPR based on precoding according to claim 6, further comprising a random signal generating module for generating the dummy signal data stream, wherein the output of the random signal generating module is connected to the input of the signal modulator.
8. The precoding-based multiple output PAPR reduction MIMO system of claim 6, wherein the signal modulator is a quadrature amplitude modulator or a quadrature phase shift keying modulator.
9. The MIMO system for reducing PAPR based on precoding according to claim 6, wherein the precoding matrix employed in the precoding module is a block diagonalized precoding matrix.
10. The MIMO system for reducing PAPR based on precoding according to claim 6, wherein the receiving end comprises:
the receiving antenna is used for receiving the transmitting signal sent by the transmitting end;
the input end of the Fourier transform module is connected with the output end of the receiving antenna and is suitable for carrying out Fourier transform on the received signal;
the input end of the detector is connected with the output end of the Fourier transform module and is suitable for detecting and separating the signals output by the Fourier transform module to obtain the useful signal data stream and the virtual signal data stream;
a signal demodulator, an input of which is connected to an output of the detector, adapted to demodulate the data stream of useful signals.
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| CN103701745A (en) * | 2013-11-13 | 2014-04-02 | 复旦大学 | Pre-coding and decoding method |
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