CN102201899A - Signal transmission method, system and device of multi-input multi-output (MIMO) system - Google Patents

Abstract

The invention discloses a signal transmission method, system and device of a multiple-input multiple-output system. The method includes: a transmitting end sequentially performs channel coding, interleaving, scrambling and constellation mapping operations on a signal; The channel gain matrix in the feedback channel state information is subjected to orthogonal processing, and the signal after the constellation mapping is performed by using the orthogonally processed channel gain matrix to perform nonlinear precoding; the transmitting end converts the nonlinear precoded signal Sent to the channel and transmitted to the receiving end via the channel. The application of the present invention can adapt to poor channel conditions, reduce the interference between multiple users, reduce the bit error rate of the system, improve the overall performance of the system, reduce information overhead and perform power control more conveniently, and can also satisfy users fairness requirements.

Description

A signal transmission method, system and device for a multiple-input multiple-output system

technical field

The invention relates to the field of communication technology, in particular to a signal transmission method, system and device of a multiple-input multiple-output system.

Background technique

Multiple-Input Multiple-Output (MIMO) technology can double the wireless channel capacity without increasing the system bandwidth and antenna transmission power, thus becoming a key technology for future wireless communications.

In the downlink of a Multiple-User Multiple-Input Multiple-Output (MU-MIMO) system, a base station communicates with multiple co-channel users on the same time-frequency resource, and there must be co-channel interference. Precoding at the transmitter is an effective solution to the problem of co-channel interference. Current precoding technologies can be divided into linear precoding and nonlinear precoding. Compared with linear precoding, nonlinear precoding has a lower bit error rate and higher capacity.

Modular algebraic precoding is currently a more practical non-linear precoding scheme for the downlink of MU-MIMO systems. The scheme mainly includes feedback interference elimination, modulo acquisition, feed-forward processing and receiving decoding (including weighting, modulus and judgment). Feedforward processing can make the equivalent channel matrix into a triangular matrix, so that user interference becomes causal, that is, a user is only interfered by users in front of it or users behind it, which makes feedback interference elimination filtering physically achievable , the modulo operation mainly limits the power of the transmitted signal, and the receiving end performs the corresponding decoding operation to recover the original data.

The existing modular algebraic precoding schemes are based on the QR decomposition of the actual channel to design the feedforward matrix and feedback matrix. According to different criteria, they can be divided into zero-forcing modular algebraic schemes and minimum mean square error modular algebraic schemes. The user interference is zero under the zero-forcing modulus algebra scheme, and the minimum mean square error modulo algebra scheme considers the influence of noise, allowing some users to interfere, but the error between the received signal and the transmitted signal is the smallest.

The existing nonlinear precoding schemes have the advantages of simple principle and good practicability, but they all directly process the actual feedback channel matrix. When the channel does not satisfy the column orthogonality, the user receiving noise is amplified to different degrees, and the user bit error The rate increases sequentially with the coding order, so the performance of users who code later will be very poor, and there may even be the possibility of infinite amplification of noise, which is difficult to meet the fairness requirements of users. At this time, the overall performance of the system will also be seriously affected, and the receiving end The weighting factor value decoded by the user needs to be transmitted from the transmitting end to the receiving end, which increases the information overhead.

Contents of the invention

Embodiments of the present invention provide a signal transmission method, system and device for a MIMO system, which are used to reduce the bit error rate of transmission and improve the overall performance of the system.

A signal transmission method of a MIMO system provided by an embodiment of the present invention includes:

Perform channel coding, interleaving, scrambling and constellation mapping operations on the signal in sequence;

performing orthogonal processing on the channel gain matrix in the channel state information fed back from the receiving end, and using the orthogonally processed channel gain matrix to perform non-linear precoding on the constellation-mapped signal;

Send the non-linearly precoded signal to the channel, and transmit it to the receiving end through the channel.

A signal receiving method of a MIMO system provided by an embodiment of the present invention includes:

Feedback channel state information to the transmitter;

receiving a signal sent by the transmitting end, wherein the signal is non-linearly precoded by the transmitting end using the channel gain matrix in the channel state information fed back by the receiving end after orthogonal processing;

Modulo calculation, judgment, demodulation, descrambling, deinterleaving, and channel decoding operations are performed on the signal in sequence.

A signal transmission system provided by an embodiment of the present invention includes:

The transmitting end is used to perform channel coding, interleaving, scrambling, constellation mapping, and nonlinear precoding operations on the signal, and send the processed signal to the channel, and transmit it to the receiving end through the channel;

The receiving end is used to feed back the channel state information to the transmitting end, and receive the channel-transmitted signal transmitted from the transmitting end, and sequentially perform modulo calculation, judgment, demodulation, descrambling, and descrambling on the signal. Interleaving, channel decoding operations.

A signal transmitting device for a multiple-input multiple-output system provided by an embodiment of the present invention includes:

The first processing unit is configured to perform channel coding, interleaving, scrambling and constellation mapping operations on the signal;

The second processing unit is configured to perform orthogonal processing on the channel gain matrix in the channel state information fed back from the receiving end;

A precoding unit, configured to use the orthogonally processed channel gain matrix to perform non-linear precoding on the constellation-mapped signal;

The sending unit is configured to send the non-linearly precoded signal to the channel, and transmit the signal to the receiving end through the channel.

A signal receiving device for a multiple-input multiple-output system provided by an embodiment of the present invention includes:

a feedback unit, configured to feed back channel state information to the transmitter;

The receiving unit is configured to receive a signal sent by the transmitting end, wherein the signal is non-linearly precoded by the transmitting end using the channel gain matrix in the channel state information fed back from the feedback unit after orthogonal processing;

The processing unit is used to sequentially perform modulo calculation, judgment, demodulation, descrambling, deinterleaving, and channel decoding operations on the signal received by the receiving unit.

It can be seen from the above technical solutions that in the embodiment of the present invention, during the signal transmission process of the MIMO system, the transmitting end sequentially performs channel coding, interleaving, scrambling, and constellation mapping operations on the signal; the channel state information fed back from the receiving end Orthogonal processing of the channel gain matrix, and use the channel gain matrix after orthogonal processing to perform nonlinear precoding on the constellation mapped signal; send the nonlinear precoded signal to the channel, and transmit it to the receiving end through the channel . In the embodiment of the present invention, during the signal receiving process of the MIMO system, the receiving end feeds back the channel state information to the transmitting end; receives the signal sent by the transmitting end, wherein the signal is the channel state information fed back by the transmitting end using the receiving end The channel gain matrix in is subjected to nonlinear precoding after the channel gain matrix after orthogonal processing; the signal is subjected to modulo calculation, judgment, demodulation, descrambling, deinterleaving, and channel decoding operations in sequence. Therefore, the embodiments of the present invention can adapt to poor channel conditions, reduce the interference between multiple users, reduce the bit error rate of the system, improve the overall performance of the system, reduce information overhead, and perform power control more conveniently. Meet the requirements of user fairness.

Description of drawings

Fig. 1 is the structural representation of the system embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a transmitting device according to an embodiment of the present invention;

FIG. 3 is a schematic structural diagram of a second processing unit of a transmitting device according to an embodiment of the present invention;

FIG. 4 is a schematic structural diagram of a precoding unit of a transmitting device according to an embodiment of the present invention;

FIG. 5 is a schematic structural diagram of a receiving device according to an embodiment of the present invention;

Fig. 6 is a schematic flow sheet of a specific embodiment of the method of the present invention;

Fig. 7 is a schematic flowchart of another specific embodiment of the method of the present invention.

Detailed ways

In the embodiment of the present invention, during the signal transmission process, the transmitting end sequentially performs channel coding, interleaving, scrambling and constellation mapping operations on the signal; the transmitting end performs normalization on the channel gain matrix in the channel state information fed back from the receiving end. orthogonal processing, and use the channel gain matrix after the orthogonal processing to perform non-linear precoding on the signal after the constellation mapping; the transmitting end sends the non-linear precoding signal to the channel, and transmits the signal to the receiving end through the channel. During the signal receiving process, the receiving end feeds back the channel state information to the transmitting end; the receiving end receives the signal sent by the transmitting end, wherein the signal is processed by the transmitting end using the channel gain matrix in the channel state information fed back by the receiving end through orthogonal processing Non-linear precoding is performed on the obtained channel gain matrix; the receiving end sequentially performs modulo calculation, judgment, demodulation, descrambling, deinterleaving, and channel decoding operations on the signal.

FIG. 1 is a schematic structural diagram of a system embodiment of the present invention.

Referring to FIG. 1 , the system of the embodiment of the present invention includes a transmitting end 11 and a receiving end 12 .

The transmitting end 11 is used to perform channel coding, interleaving, scrambling, constellation mapping, and nonlinear precoding operations on the signal, and send the processed signal to a channel, and transmit it to the receiving end 12 through the channel;

The receiving end 12 is configured to feed back the channel state information to the transmitting end 11, and receive the channel-transmitted signal transmitted from the transmitting end 11, and perform modulo calculation, judgment, demodulation, and demodulation on the signal in sequence. Scrambling, de-interleaving, and channel decoding operations.

The transmitting end 11 performs lattice reduction processing on the channel gain matrix obtained from the receiving end 12 using a lattice reduction (LLL) algorithm, and then performs QR decomposition on the processed channel gain matrix to obtain a feedforward matrix and a feedback matrix respectively, Then, the feed-forward matrix is used to perform feed-forward processing on the signals subjected to the constellation mapping operation, and the feedback matrix is used to perform feedback interference elimination on the signals after the feed-forward processing.

Referring to FIG. 2 , a transmitting device applied in the above system provided by an embodiment of the present invention includes: a first processing unit 21 , a second processing unit 22 , a precoding unit 23 , and a sending unit 24 .

The first processing unit 21 is configured to perform channel coding, interleaving, scrambling and constellation mapping operations on the signal;

The second processing unit 22 is configured to perform orthogonal processing on the channel gain matrix in the channel state information fed back from the receiving end;

A precoding unit 23, configured to use the orthogonally processed channel gain matrix to perform non-linear precoding on the constellation-mapped signal;

The sending unit 24 is configured to send the non-linearly precoded signal to the channel, and transmit it to the receiving end through the channel.

Referring to FIG. 3 , the second processing unit 22 of a transmitting device applied in the above system provided by an embodiment of the present invention includes: an acquisition unit 31 and an orthogonal processing unit 32 .

An acquisition unit 31, configured to acquire channel state information fed back by the receiving end;

The orthogonal processing unit 32 is configured to perform lattice reduction processing on the channel gain matrix in the channel state information by using the LLL algorithm to obtain an equivalent channel gain matrix.

Referring to FIG. 4 , a precoding unit 23 of a transmitting device applied in the above system provided by an embodiment of the present invention includes: a decomposition unit 41 , a feedforward processing unit 42 , and a feedback interference elimination unit 43 .

Decomposition unit 41, configured to perform QR decomposition on the equivalent channel gain matrix to obtain a feedforward matrix and a feedback matrix;

A feed-forward processing unit 42, configured to use a feed-forward matrix to perform feed-forward processing on signals subjected to constellation mapping operations;

The feedback interference elimination unit 43 is configured to perform feedback interference elimination on the signal after the feedforward processing by using the feedback matrix.

Referring to FIG. 5 , a receiving device applied in the above system provided by an embodiment of the present invention includes: a feedback unit 51 , a receiving unit 52 , and a processing unit 53 .

A feedback unit 51, configured to feed back channel state information to the transmitting end;

The receiving unit 52 is configured to receive a signal sent by the transmitting end, wherein the signal is non-linearly precoded by the transmitting end using the channel gain matrix in the channel state information fed back from the feedback unit 51 after orthogonal processing ;

The processing unit 53 is configured to sequentially perform modulo calculation, judgment, demodulation, descrambling, deinterleaving, and channel decoding operations on the signal received by the receiving unit 52 .

The specific process of the method in the embodiment of the present invention will be described below with reference to FIG. 6 and FIG. 7 .

Referring to Fig. 6, the method of the embodiment of the present invention includes the following steps:

Step 601: The transmitting end sequentially performs channel coding, interleaving, scrambling and constellation mapping operations on the signal.

Step 602: The transmitting end performs orthogonal processing on the channel gain matrix in the channel state information fed back from the receiving end, and uses the orthogonally processed channel gain matrix to perform nonlinear precoding on the constellation-mapped signal.

其中矩阵T为单模矩阵，其元素值均为整数，且满足det(T)＝±1，得到等效信道增益矩阵。然后对所述等效信道增益矩阵进行QR分解，获得前馈矩阵和反馈矩阵，利用前馈矩阵对经过星座映射操作的信号进行前馈处理，且利用反馈矩阵对经过前馈处理后的信号进行反馈干扰消除。Here, when performing orthogonal processing on the channel gain matrix in the channel state information fed back from the receiving end, the LLL algorithm is used to perform lattice reduction processing on the channel gain matrix in the channel state information, and the channel gain Matrix H is processed as follows:

The matrix T is a single-mode matrix, and its element values are all integers, and det(T)=±1 is satisfied, and an equivalent channel gain matrix is obtained. Then perform QR decomposition on the equivalent channel gain matrix to obtain a feedforward matrix and a feedback matrix, use the feedforward matrix to perform feedforward processing on the signal that has undergone the constellation mapping operation, and use the feedback matrix to perform feedforward processing on the signal after the feedforward processing Feedback interference eliminated.

Step 603: The transmitting end sends the non-linearly precoded signal to the channel, and transmits the signal to the receiving end through the channel.

Fig. 7 is a schematic flow chart of a specific embodiment of the method of the present invention.

Referring to Figure 7, the specific process of this embodiment is as follows:

Step 701: the base station acquires a signal from an upper layer protocol stack.

Step 702: The base station performs channel coding, interleaving, scrambling, and constellation mapping on the acquired signal.

Step 703: the base station obtains the channel state matrix (Channel State Information, CSI) fed back by the receiving end.

Here, in a frequency division duplex (Frequency Division Duplexing, FDD) MIMO system, the base station can add pilot information to the transmitted signal, and complete the estimation of the wireless channel through the pilot, and the receiving end receives and feeds back the channel gain matrix to the base station .

Step 704: layer mapping operation.

Here, the complex-valued modulation symbols to be transmitted are mapped to multiple layers through a layer mapping operation, so as to prepare for the specific implementation of MU-MIMO nonlinear modulo-algebraic precoding.

Step 705: Use the LLL algorithm to perform lattice reduction processing on the channel gain matrix obtained from the receiving end.

Here, the idea of grid point reduction is to try to reduce the correlation between the basis vectors by modifying the basis vectors of the channel gain matrix so that the Euclidean distance between them is the shortest. The LLL algorithm is a commonly used method to reduce the correlation between basis vectors. It can find the lattice point basis with the shortest vector property on the polynomial time level. The LLL algorithm is used to reduce the channel gain matrix, which can improve the performance without significantly increasing the complexity, and has good practicability.

Step 706: Perform QR decomposition on the processed channel gain matrix to obtain feedforward matrix and feedback matrix respectively.

Step 707: Feedforward processing and feedback interference elimination.

Step 708: The base station transmits the signal, and transmits it to the receiving end through the channel.

Here, after the precoding operation is completed, relevant processing is performed according to the actual system requirements, such as Orthogonal Frequency Division Multiplexing (OFDM) modulation, etc., and finally the processed signal is transmitted from the antenna port through up-conversion .

Step 709: The receiving end receives the signal transmitted by the base station and transmitted through the channel.

Step 710: The receiver calculates the modulus of the signal, decides, demodulates, descrambles, deinterleaves, and decodes the channel.

In the process of step 709 and step 710, each terminal uses the antenna to receive the signal from the base station. Since the base station eliminates the interference of the multi-user signal of the MIMO system in advance through precoding, the receiving end only needs to down-convert the received signal in order to obtain Modulo, judgment, demodulation, descrambling, deinterleaving, channel decoding and other operations can obtain the original transmission data.

It can be seen from the above technical solutions that in the embodiment of the present invention, during the signal transmission process of the MIMO system, the transmitting end sequentially performs channel coding, interleaving, scrambling and constellation mapping operations on the signal; The channel gain matrix in the channel state information is subjected to orthogonal processing, and the signal after constellation mapping is used for nonlinear precoding by using the channel gain matrix after orthogonal processing; the transmitting end sends the nonlinear precoded signal to The channel is transmitted to the receiving end through the channel. In the embodiment of the present invention, during the signal receiving process of the MIMO system, the receiving end feeds back the channel state information to the transmitting end; the receiving end receives the signal sent by the transmitting end, wherein the signal is the channel fed back by the transmitting end using the receiving end The channel gain matrix in the state information is subjected to nonlinear precoding after the channel gain matrix is orthogonally processed; the receiving end sequentially performs modulo calculation, judgment, demodulation, descrambling, deinterleaving, and channel decoding operations on the signal. Therefore, the embodiments of the present invention can adapt to poor channel conditions, reduce the interference between multiple users, reduce the bit error rate of the system, improve the overall performance of the system, reduce information overhead, and perform power control more conveniently. Meet the requirements of user fairness.

Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these modifications and variations.

Claims (11)

1. the signal transmitting method of a multi-input multi-output system is characterized in that, this method may further comprise the steps:

To signal carry out chnnel coding successively, interweave, scrambling and constellation mapping operation;

Channel gain matrix from the channel condition information of receiving terminal feedback is carried out orthogonal processing, and utilize through the signal of the channel gain matrix after the orthogonal processing after and carry out nonlinear precoding constellation mapping;

To send to channel through the signal of nonlinear precoding, channel is transferred to receiving terminal.

2. the method for claim 1 is characterized in that, described transmitting terminal carries out orthogonal processing to the channel gain matrix from the channel condition information of receiving terminal feedback, comprising:

Described transmitting terminal obtains the channel condition information of receiving terminal feedback;

Utilize lattice base reduction LLL algorithm that the channel gain matrix from described channel condition information is carried out lattice point and reduce processing, obtain the equivalent channel gain matrix.

3. the method for claim 1 is characterized in that, described utilization through the channel gain matrix after the orthogonal processing to constellation mapping after signal carry out nonlinear precoding, comprising:

Described equivalent channel gain matrix is decomposed, obtain feedforward matrix and feedback matrix;

Utilize feedforward matrix that the signal through the constellation mapping operation is carried out feed-forward process, and utilize feedback matrix to eliminate carrying out feedback interference through the signal after the feed-forward process.

4. the signal acceptance method of a multi-input multi-output system is characterized in that, this method may further comprise the steps:

Channel condition information is fed back to transmitting terminal;

Receive the signal that transmitting terminal sends, wherein, described signal is that transmitting terminal utilizes the channel gain matrix in the channel condition information of receiving terminal feedback to carry out nonlinear precoding through the channel gain matrix after the orthogonal processing;

To this signal ask mould, judgement, demodulation successively, go to disturb, deinterleave, the channel decoding operation.

5. a signal transmission system is characterized in that, this system comprises:

Transmitting terminal, be used for to signal carry out chnnel coding, interweave, scrambling and constellation mapping, and nonlinear precoding operation, and, the signal of handling is sent to channel, channel is transferred to receiving terminal;

Receiving terminal is used for channel condition information is fed back to described transmitting terminal, and, receive from the signal of the channel transmission of described transmitting terminal emission, and to this signal ask mould, judgement, demodulation successively, go to disturb, deinterleave, the channel decoding operation.

6. system as claimed in claim 5 is characterized in that, described transmitting terminal is used to obtain the channel condition information of described receiving terminal feedback; Utilize lattice base reduction LLL algorithm that the channel gain matrix from described channel condition information is carried out lattice point and reduce processing, obtain the equivalent channel gain matrix.

7. system as claimed in claim 6 is characterized in that, described transmitting terminal is used for described equivalent channel gain matrix is decomposed, and obtains feedforward matrix and feedback matrix; Utilize feedforward matrix that the signal through the constellation mapping operation is carried out feed-forward process; Utilize feedback matrix to eliminate to carrying out feedback interference through the signal after the feed-forward process.

8. the sender unit of a multi-input multi-output system is characterized in that, this sender unit comprises:

First processing unit, be used for to signal carry out chnnel coding, interweave, scrambling and constellation mapping operation;

Second processing unit is used for the channel gain matrix from the channel condition information of receiving terminal feedback is carried out orthogonal processing;

Precoding unit is used to utilize through the signal of the channel gain matrix after the orthogonal processing after to constellation mapping and carries out nonlinear precoding;

Transmitting element is used for the signal through nonlinear precoding is sent to channel, and channel is transferred to receiving terminal.

9. emitter as claimed in claim 8 is characterized in that, described second processing unit comprises:

Acquiring unit is used to obtain the channel condition information that described receiving terminal feeds back;

The orthogonal processing unit is used for utilizing lattice base reduction LLL algorithm to reduce processing to carry out lattice point from the channel gain matrix of described channel condition information, obtains the equivalent channel gain matrix.

10. emitter as claimed in claim 8 is characterized in that, described precoding unit comprises:

Resolving cell is used for described equivalent channel gain matrix is decomposed, and obtains feedforward matrix and feedback matrix;

The feed-forward process unit is used to utilize feedforward matrix that the signal through the constellation mapping operation is carried out feed-forward process;

Feedback interference is eliminated the unit, is used to utilize feedback matrix to eliminate carrying out feedback interference through the signal after the feed-forward process.

11. the signal receiving device of a multi-input multi-output system is characterized in that, this signal receiving device comprises:

Feedback unit is used for channel condition information is fed back to transmitting terminal;

Receiving element is used to receive the signal that transmitting terminal sends, and wherein, described signal is that the channel gain matrix of transmitting terminal utilization from the channel condition information of feedback unit feedback carried out nonlinear precoding through the channel gain matrix after the orthogonal processing;

Processing unit, be used for to the signal that receiving element receives ask mould, judgement, demodulation successively, go to disturb, deinterleave, the channel decoding operation.

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