CN102315914B - Robust non-linear transceiver under multiple-input-multiple-output spatial correlation channel - Google Patents

Abstract

The present invention relates to a robust nonlinear transceiver device under multiple-input multiple-output spatial correlation information. The device first obtains a processing matrix for transmitting and receiving signals through a channel estimation module and a transmitting and receiving matrix calculation module, including a transmitting precoding matrix and a transmitting feedback matrix. and the receiving equalization matrix, and output the calculation results to the transmitting precoding module and the receiving equalization module for processing the sending and receiving signals. Then the digital modulation signal is input into the transmit precoding module, and then output to the channel after being processed by the transmit feedback matrix and the transmit precode matrix. The receiving end processes the received signal through the receiving equalization module, and finally demodulates the output. The transceiver device can obtain better system performance than the linear transceiver device under the condition of spatially correlated non-ideal channel state information.

Description

Robust nonlinear transceiver for multiple-input multiple-output spatially correlated channels

technical field

The invention relates to a device in the technical field of signal processing, in particular to a robust nonlinear transceiver device under a multiple-input multiple-output spatial correlation channel.

Background technique

The traditional wireless communication technology has reached an unprecedented level of research on the frequency domain, time domain and code domain information of the signal, but it still cannot meet the needs of the application. It is necessary to expand the new signal processing field, and the research on the signal space domain makes up for this. A blank, through the research of antenna diversity technology and smart antenna technology, it is found that it is feasible to use multiple antennas to realize signal transmission. With the deepening of research, it eventually evolved into the multiple-input multiple-output (MIMO) communication technology. MIMO technology, as the framework technology of the future generation of broadband wireless communication system, is an inevitable way to make full use of space resources and improve spectrum utilization. The wireless communication theory and signal processing technology based on MIMO has shown great potential and development prospects.

The communication of the MIMO system will be interfered by multiple users and multiple antennas, resulting in co-channel interference (CCI). Therefore, some necessary signal processing techniques need to be used at both ends of the transceiver to eliminate noise and interference. At the transmitting end, the base station is used to optimize the design and processing of the transmitter signal, so that each mobile station can theoretically receive signals that are not interfered by other users, realize space division multiple access (SDMA), and ensure reliable data reception. This signal processing process is called precoding the transmitted signal. At the receiving end, the receiver needs to process the received signals from each transmitting antenna to distinguish signals from different transmitting antennas or different users. This process is called receiving equalization processing. In MIMO system design, if the receiving antennas can cooperate, then the joint design of transmit precoding processing and receiving equalization processing can obtain better system performance.

According to whether nonlinear processing is included in the signal processing process, MIMO transceivers can be divided into two categories: linear transceivers and nonlinear transceivers. When the channel state information (CSI) is known at both ends of the transceiver, a lot of research has been done on the design of linear transceivers. For example, the use of convex optimization theory to incorporate the design of linear transceivers into a unified framework can minimize the mean square error. (MSE), minimize bit error rate (BER) and maximize signal-to-interference-noise ratio (SINR). For the nonlinear receiver, there are two design structures. One is that the nonlinear processing structure is at the transmitting end, and the receiving end is linear processing. This structure is called a nonlinear transceiver based on THP precoding. Another structure is linear processing at the transmitting end and nonlinear processing at the receiving end. This structure is called a nonlinear transceiver based on decision feedback (DFE). Since the feedback of the receiving end in the second structure will cause bit error diffusion, under the same design criteria, the performance of the first structure is usually better than that of the second structure. The design methods of THP transceivers and DFE transceivers under the unified framework have been given so far, which can minimize MSE and BER and maximize SINR under known CSI conditions.

However, in the actual communication process, due to various factors such as fast channel fading, feedback information delay, and channel estimation error, the system can only obtain part of the CSI or information with errors. In this case, the design of the transceiver The actual channel situation should be considered to design a method with robust performance. For non-ideal CSI conditions, when the channel is modeled as the sum of the channel estimate and the channel error value, and the transceiver correlation is not considered, some literatures respectively give the minimum MSE robust linear transceiver design and nonlinear THP transceiver machine design. If the transceiver correlation is considered, Xi Zhang first proposed a robust linear transceiver algorithm considering the reception correlation (Z. Xi, D. P. Palomar, and B. Ottersten, Statistically robust design of linear MIMO transceivers, (Multiple Input Multiple Output Statistical Robust Design of Linear Transceiver), IEEE Trans on Signal Processing, vol.56, no.8, 2008), further, D. Minhua proposed a robust linear transceiver considering both transceivers (D. Minhua, Multiple -input multiple-out wireless system designs with imperfect channel knowledge, (Multiple-input multiple-output wireless system design under non-ideal channel information), Ph.D. thesis, Queen's Univ., Kingston, Canada, 2008). Compared with linear transceivers, there are less researches on robust nonlinear transceivers under the condition of non-ideal CSI that is simultaneously correlated with transmitting and receiving.

Contents of the invention

The present invention aims at the above-mentioned deficiencies existing in the prior art, and provides a robust nonlinear transceiver device under a multiple-input multiple-output spatially correlated channel, which can minimize the mean square error of the transceiving signal and reduce the influence of channel correlation on system performance. Reduce the bit error rate of the system.

The present invention is achieved through the following technical solutions:

The present invention provides a robust nonlinear transceiver device under multiple-input multiple-output spatially correlated channels, including a channel estimation module, a transceiver matrix calculation module, a signal generation module, a transmission precoding module, a reception equalization module, and a signal demodulation module, wherein :

The channel estimation module performs channel estimation through the training sequence, and transmits the channel estimation information to the transceiver matrix calculation module;

The transceiver matrix calculation module calculates the values of the transmit precoding matrix, the transmit feedback matrix and the receive equalization matrix according to the channel estimation value and the pre-assumed transmit and receive correlation matrix information, and transmits the calculated values of the transmit precode matrix and the feedback matrix to The transmit precoding module transmits the receive equalization matrix value to the receive equalization module;

The signal generating module generates a binary information source, and uses digital modulation to modulate the information source into a digital signal, and outputs it to the transmitting precoding module;

The transmitting precoding module processes the digital modulation signal, multiplies the precoding matrix to the left by the signal, and outputs the signal to the channel after power normalization;

The receiving equalization module receives the signal transmitted by the channel, multiplies the equalization matrix to the left of the received signal, and then outputs it to the signal demodulation module.

The signal demodulation module receives the output signal from the receiving equalization module, performs modulo operation on the signal and demodulates it, obtains and outputs the received demodulated signal.

The transceiver matrix calculation module includes: a precoding matrix calculation unit, a feedback matrix calculation unit, and a receiving equalization matrix calculation unit, wherein:

The calculation of the transmit precoding matrix by the precoding matrix calculation unit is an iterative calculation process. First, the precoding matrix is initialized as an identity matrix, and then the precoding matrix, auxiliary calculation matrix, and intermediate operation coefficients are iteratively calculated until the algorithm converges, that is, the updated precoding matrix When the norm of the difference between the encoding matrix and the previous precoding matrix is less than 10 ^-4 , the iterative process ends, and then the specific unitary matrix is right-multiplied by the precoding matrix according to the equidiagonal decomposition algorithm to obtain the final transmitting precoding Matrix, and output to the launch precoding module;

The feedback matrix calculation unit calculates the equidiagonal sub-diagonal triangular feedback processing matrix through Cholesky decomposition according to the precoding matrix calculated above, and outputs it to the transmitting precoding module;

The receiving equalization matrix calculation unit calculates the receiving equalization matrix according to the precoding matrix and the feedback processing matrix calculated above, and outputs the receiving equalization matrix to the receiving equalization module.

The signal generating module includes: a binary information source generating unit and a digital modulation signal generating unit, wherein the binary information source generating unit generates a binary information source, and uses digital modulation to modulate the information source into a digital signal through the digital modulation signal generating unit, and outputs to transmit precoding module.

The transmission precoding module includes: a modulus operation unit, a feedback preprocessing unit, and a precoding processing unit, wherein the modulus operation unit is connected with the digital modulation signal generation unit, the feedback preprocessing unit, and the precoding processing unit and transmits the modulus operation information , the feedback preprocessing unit is connected with the modulus operation unit, the precoding processing unit, and the transceiver matrix calculation module and continuously and serially transmits the feedback preprocessing signal, and the precoding processing unit is connected with the modulus operation unit, the feedback preprocessing unit, and the transceiver matrix calculation module Connect and transmit pre-coded processing information.

The signal demodulation module includes: a mode operation unit and a demodulation unit, wherein the mode operation unit is connected with the receiving equalization module and the demodulation unit and transmits mode operation information, and the demodulation unit is connected with the mode operation unit and transmits demodulation information.

Concrete steps during above-mentioned device work of the present invention are:

1. The channel estimation module performs channel estimation through the training sequence, and transmits the channel estimation information to the transceiver matrix calculation module.

2. The transmit and receive matrix calculation module calculates the values of the transmit precoding matrix, transmit feedback matrix and receive equalization matrix according to the channel estimation value and the pre-assumed transmit and receive correlation matrix information, and transmits the calculated values of the transmit precoding matrix and feedback matrix to The transmit precoding module transmits the receive equalization matrix value to the receive equalization module. The calculation of the transmitting precoding matrix by the precoding matrix calculation unit is an iterative calculation process. First, the precoding matrix is initialized as the identity matrix, and then the precoding matrix, auxiliary calculation matrix, and intermediate operation coefficients are iteratively calculated until the algorithm converges, that is, the updated precoding matrix When the norm of the difference between the matrix and the previous precoding matrix is less than 10 ^-4 , the iterative process ends, and then the specific unitary matrix is right-multiplied by the precoding matrix according to the equidiagonal decomposition algorithm to obtain the final transmitting precoding matrix , and output to the transmit precoding module. The transmitting feedback matrix calculation unit calculates the equidiagonal sub-triangular feedback processing matrix through Cholesky decomposition according to the precoding matrix calculated above, and outputs it to the transmitting precoding module. The receiving equalization matrix calculation unit calculates the receiving equalization matrix according to the precoding matrix and the feedback processing matrix calculated above, and outputs the receiving equalization matrix to the receiving equalization module.

3. The signal generation module generates a binary information source, and uses digital modulation to modulate the information source into a digital signal.

4. The digital modulation signal generated in step 3 is input to the transmit precoding module for processing. The first value of the transmitted signal vector is only modulo-operated, and the second value is modulo-operated and then fed back to the feedback preprocessing unit for processing to eliminate The interference of the first value on the second value, and so on, cancels the interference of all previous values on the latter value in turn. The feedback processing matrix used comes from the calculated value of the transmit feedback matrix in step 2.

5. Input the signal after continuous interference cancellation in step 4 to the precoding processing unit. The precoding matrix comes from the value of the transmitting precoding matrix in step 2. The signal is multiplied by the precoding matrix to the left, and output to the channel after power normalization.

6. The receiving equalization module receives the signal transmitted by the channel. The equalization matrix comes from the value of the receiving equalization matrix in step 2. The equalization matrix is multiplied by the left side of the received signal, and then output to the demodulation module.

7. The demodulation module receives the output signal of step 6, performs modulo operation on the signal and demodulates it, and obtains the received demodulated signal and outputs it.

After adopting the above-mentioned technical scheme, the present invention shows through computer simulation that it is better than a robust linear transceiver in terms of bit error rate performance and mean square error performance, and the robustness increases with the increase of the correlation coefficient of transmission and reception.

Description of drawings

Figure 1 is a schematic diagram of the device of the present invention.

FIG. 2 is a schematic diagram of a bit error rate performance comparison of an embodiment.

Fig. 3 is a schematic diagram of embodiment mean square error performance comparison;

In the figure: (a) is the change with the transmission correlation coefficient; (b) is the change with the reception correlation coefficient.

Detailed ways

The embodiments of the present invention are described in detail below. This embodiment is implemented on the premise of the technical solution of the present invention, and detailed implementation methods and specific operating procedures are provided, but the protection scope of the present invention is not limited to the following implementation example.

As shown in Figure 1, this embodiment includes: a channel estimation module, a transceiver matrix calculation module, a signal generation module, a transmission precoding module, a reception equalization module, and a signal demodulation module, wherein: the channel estimation module is connected with the transceiver matrix calculation module And transmit channel estimation information, the transceiver matrix calculation module is connected with the channel estimation module, the transmit precoding module, and the receiving equalization module to transmit the transceiver matrix information, the signal generation module is connected with the transmitting precoding module and transmits digital modulation signals, and the receiving equalization module It is connected with the signal demodulation module and transmits and receives the equalized signal. in:

The transceiver matrix calculation module calculates the values of the transmit precoding matrix, the transmit feedback matrix and the receive equalization matrix according to the channel estimation value and the pre-assumed transmit and receive correlation matrix information, and transmits the calculated values of the transmit precode matrix and the feedback matrix to The transmit precoding module transmits the receive equalization matrix value to the receive equalization module;

The signal generating module generates a binary information source, and uses digital modulation to modulate the information source into a digital signal, and outputs it to the transmitting precoding module;

The transmitting precoding module processes the digital modulation signal, multiplies the precoding matrix to the left by the signal, and outputs the signal to the channel after power normalization;

The receiving equalization module receives the signal transmitted by the channel, multiplies the equalization matrix to the left of the received signal, and then outputs it to the signal demodulation module.

The signal demodulation module receives the output signal from the receiving equalization module, performs modulo operation on the signal and demodulates it, obtains and outputs the received demodulated signal.

、接收天线为的MIMO通信系统。设噪声为独立同分布的零均值高斯白噪声，协方差矩阵

。具体的实施步骤如下： Suppose the transmitting antenna is

, the receiving antenna is MIMO communication system. Assuming that the noise is independent and identically distributed zero-mean Gaussian white noise, the covariance matrix

. The specific implementation steps are as follows:

，使用最小均方误差信道估计方法，得到信道估计矩阵

，考虑收发相关矩阵，得到最后的信道信息为：

，其中

表示发射空间相关信息，

则表示使用接收空间相关矩阵，其中

。

表示信道估计误差矩阵，其中

中的元素满足独立同分布的高斯分布

。所获得的信道估计以及

信息送入到收发矩阵计算模块的各个计算单元。 1. The channel estimation module receives the training sequence, and the power of the training sequence is set as

, using the minimum mean square error channel estimation method, the channel estimation matrix is obtained

, considering the transceiver correlation matrix, the final channel information is obtained as:

,in

Indicates the emission space related information,

Then it means to use the receiving spatial correlation matrix, where

.

Represents the channel estimation error matrix, where

The elements in satisfy the independent and identically distributed Gaussian distribution

. The obtained channel estimate and

The information is sent to each calculation unit of the transceiver matrix calculation module.

、以及预先假设的收发相关矩阵，计算发射预编码矩阵，其过程为一个迭代过程：首先初始化预编码矩阵为

，其中是信道矩阵的秩；然后更新辅助矩阵 2. The transceiver matrix calculation module includes: a precoding matrix calculation unit, a feedback matrix calculation unit, and a receiving equalization matrix calculation unit. The precoding matrix calculation unit is connected with the channel estimation module, the feedback matrix calculation unit, the receiving equalization matrix calculation unit, and the transmission precoding module to transmit the calculated precoding transmission matrix information, and the feedback matrix calculation unit is connected with the precoding matrix calculation unit, The receiving equalization matrix calculation unit and the transmitting precoding module are connected to transmit the transmitting feedback matrix information, and the receiving equalization matrix calculation unit is connected to the precoding matrix calculation unit, the feedback matrix calculating unit and the receiving equalization module to transmit the receiving equalization matrix information. Wherein the precoding matrix calculation unit transmits the estimated value according to the channel estimation module

, and the pre-assumed transceiver correlation matrix, calculate the transmit precoding matrix, the process is an iterative process: first initialize the precoding matrix as

,in is the rank of the channel matrix; then update the auxiliary matrix

；

;

Then update the intermediate operation coefficient

 

；

;

；迭代以上步骤直到算法收敛，即更新的预编码矩阵与前次的预编码矩阵差值的F范数小于10^-4时，迭代过程结束。将具有自由度的酉矩阵

右乘前述的预编码矩阵

，将

代入到

，使用等对角线分解算法（具体算法参考文献 F.Xu， T N. Davidson， et al. Design of block transceivers with decision feedback detection，判决反馈块收发机设计， IEEE Trans.Signal Process.， vol. 54， no. 3， pp. 965-978， 2006.中的附录1）获得酉矩阵

，则所述预编码矩阵计算单元输出的预编码矩阵为

，并输出到发射预编码模块。 Finally update the precoding matrix

; The above steps are iterated until the algorithm converges, that is, when the F norm of the difference between the updated precoding matrix and the previous precoding matrix is less than 10 ⁻⁴ , the iterative process ends. will have a unitary matrix with degrees of freedom

Right multiply the aforementioned precoding matrix

,Will

substitute into

, using the equidiagonal decomposition algorithm (specific algorithm references F.Xu, T N. Davidson, et al. Design of block transceivers with decision feedback detection, decision feedback block transceiver design, IEEE Trans.Signal Process., vol. 54, no. 3, pp. 965-978, 2006. Appendix 1) to obtain the unitary matrix

, then the precoding matrix output by the precoding matrix calculation unit is

, and output to the transmit precoding module.

的Cholesky分解为，然后计算发射反馈预处理矩阵为

，其中

是

对角线上第

个元素，因此发射反馈矩阵C为等对角线下三角矩阵，并输出到发射预编码模块。 The feedback matrix calculation unit calculates the transmit feedback matrix value according to the output result of the precoding matrix calculation unit, and first calculates

The Cholesky decomposition of , and then calculate the transmit-feedback preconditioning matrix as

,in

yes

on the diagonal

elements, so the transmit feedback matrix C is an equidiagonal lower triangular matrix, and is output to the transmit precoding module.

 ，并输出到接收均衡模块。 The receiving equalization matrix calculation unit calculates the receiving equalization matrix according to the transmit precoding matrix value and the transmit feedback matrix value as

, and output to the receiving equalization module.

-QAM星座图，经过数字调制的信号源转换为，

为并行发送的数据流数目，并且进行功率归一化使得

成立。 3. The signal generation module includes: a binary information source generation unit, a digital modulation signal generation unit, wherein the binary information source generation unit generates a binary information source z, then z is input to the digital modulation unit, and the digital modulation adopts

-QAM constellation, digitally modulated signal source converted to ,

is the number of data streams sent in parallel, and is power normalized such that

established.

4. The transmit precoding module includes: a modulo operation unit, a feedback preprocessing unit, and a precoding processing unit. The digital modulation signal source s generated in step 3 is input to the modulo operation unit, the first value of the s vector is only modulo operated and output, and the second value is fed back to the feedback preprocessing unit after modulo operation, and the first value is eliminated by processing The interference of one value on the second value, and so on, as follows

                               

The modulo operation is defined as follows

            

     

-QAM，

。 When the constellation diagram is

-QAM,

.

The feedback preprocessing unit includes a feedback matrix C, which is the output from the feedback matrix calculation unit in step 2.

5. The feedback preprocessed signal q obtained in step 3 is input to the precoding module, the precoding matrix is multiplied by the signal q to the left and the power is normalized to obtain the transmitted output signal. The precoding matrix F comes from step 2 The output of the transmit precoding matrix calculation unit.

6. After the received signal is normalized by inverse power, y is obtained and sent to the receiving equalization module, and the receiving equalization matrix G is multiplied by y to the left to obtain the processed output signal. The receiving equalization matrix G comes from step 2 The output of the receiving equalization matrix calculation unit.

-QAM数字调制的解调，最后输出解调信号。 7. The signal demodulation module includes: a modulo operation unit and a demodulation unit. Wherein the modulo operation unit is connected with the output signal of step 6 and performs modulo operation on the signal, which is the same as the modulo operation defined in step 3, and the demodulation unit is connected with the output of the modulo operation unit and performs

-Demodulation of QAM digital modulation, and finally output the demodulated signal.

FIG. 2 shows the BER curves of the nonlinear transceiver of the present invention compared with the linear transceiver. Simulation shows that the present invention is more robust to non-ideal channel state information, and its performance is better than that of a linear transceiver. Especially in the case of high SNR, the performance advantage is more significant.

和

变化的

性能。从图3(a)中可以看出，本发明的非线性收发机在

上优于线性收发机。同时，随着

 的增大，本发明比线性性能优势更加明显，因此，本发明的非线性收发机在对抗接收相关性上比线性收发机更具有鲁棒性。图3(b)中也能得到相似的结论，随着

的增加，本发明的非线性收发装置获得更多的性能增益，并且本发明的非线性收发机在对抗发射相关性上，也比线性收发机更具有鲁棒性。 In order to compare the performance of the nonlinear transceiver of the present invention and the robust linear transceiver under different correlation coefficient conditions, Fig. 3 also provides the random

and

changing

performance. As can be seen from Figure 3(a), the nonlinear transceiver of the present invention is

superior to linear transceivers. At the same time, with

The increase of , the present invention has more obvious advantages than linear performance, therefore, the nonlinear transceiver of the present invention has more robustness against receiving correlation than the linear transceiver. Similar conclusions can also be obtained in Figure 3(b), with

With the increase of , the nonlinear transceiver device of the present invention obtains more performance gains, and the nonlinear transceiver of the present invention is also more robust than the linear transceiver in terms of anti-transmission correlation.

Claims (4)

1. A robust nonlinear transceiving device under a multiple-input multiple-output spatial correlation channel, characterized in that it comprises a channel estimation module, a transceiver matrix calculation module, a signal generation module, a transmitting precoding module, a receiving equalization module, and a signal demodulation module ,in: The channel estimation module performs channel estimation through the training sequence, and transmits the channel estimation information to the transceiver matrix calculation module; The transceiver matrix calculation module calculates the values of the transmit precoding matrix, the transmit feedback matrix and the receive equalization matrix according to the channel estimation value and the pre-assumed transmit and receive correlation matrix information, and transmits the calculated values of the transmit precode matrix and the feedback matrix to The transmit precoding module transmits the receive equalization matrix value to the receive equalization module; The signal generating module generates a binary information source, and uses digital modulation to modulate the information source into a digital signal, and outputs it to the transmitting precoding module; The transmit precoding module processes the digital modulation signal, multiplies the precoding matrix to the left by the signal, and outputs it to the channel after power normalization; The receiving equalization module receives the signal after channel transmission, multiplies the equalization matrix to the left by the received signal, and then outputs it to the signal demodulation module; The signal demodulation module receives the output signal from the receiving equalization module, modulo-operates and demodulates the signal, obtains the received demodulated signal and outputs it; The transceiver matrix calculation module includes: a precoding matrix calculation unit, a feedback matrix calculation unit, and a receiving equalization matrix calculation unit, wherein: The calculation of the transmit precoding matrix by the precoding matrix calculation unit is an iterative calculation process. First, the precoding matrix is initialized as an identity matrix, and then the precoding matrix, auxiliary calculation matrix, and intermediate operation coefficients are iteratively calculated until the algorithm converges, that is, the updated precoding matrix When the norm of the difference between the encoding matrix and the previous precoding matrix is less than 10 ^-4 , the iterative process ends, and then the specific unitary matrix is right-multiplied by the precoding matrix according to the equidiagonal decomposition algorithm to obtain the final transmitting precoding Matrix, and output to the launch precoding module; The feedback matrix calculation unit calculates the equidiagonal sub-triangular feedback processing matrix through Cholesky decomposition according to the precoding matrix calculated above, and outputs it to the transmitting precoding module; The receiving equalization matrix calculation unit calculates the receiving equalization matrix according to the precoding matrix and the feedback processing matrix calculated above, and outputs the receiving equalization matrix to the receiving equalization module. the 2. The robust nonlinear transceiving device under the multiple-input multiple-output spatial correlation channel according to claim 1, wherein: the signal generation module comprises: a binary information source generation unit, a digital modulation signal generation unit, wherein The binary information source generation unit generates the binary information source, and uses digital modulation to modulate the information source into a digital signal through the digital modulation signal generation unit, and outputs it to the transmission precoding module. the 3. The robust nonlinear transceiving device under the MIMO spatial correlation channel according to claim 1, characterized in that: the transmit precoding module comprises: a modulo operation unit, a feedback preprocessing unit, a precoding processing unit, wherein the modulus operation unit is connected with the digital modulation signal generation unit, the feedback preprocessing unit, and the precoding processing unit and transmits the modulus operation information, and the feedback preprocessing unit is connected with the modulus operation unit, the precoding processing unit, and the transceiver matrix calculation module And serially transmit the feedback pre-processing signal, the pre-coding processing unit is connected with the modulo operation unit, the feedback pre-processing unit, and the transceiver matrix calculation module and transmits the pre-coding processing information. the 4. The robust nonlinear transceiving device under the MIMO spatial correlation channel according to claim 1, wherein the signal demodulation module comprises: a modulus operation unit and a demodulation unit, wherein the modulus operation unit It is connected with the receiving equalization module and the demodulation unit and transmits the modulus operation information, and the demodulation unit is connected with the modulus operation unit and transmits the demodulation information. the

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