Uplink single carrier subsystem in heterogeneous MIMO channel environment

Abstract

The invention discloses an uplink single carrier subsystem in a heterogeneous MIMO channel environment, and relates to the technical field of wireless data transmission, the uplink single carrier subsystem comprises a transmission data acquisition module, a preprocessing module, a channel characteristic processing module, a channel monitoring module, a channel optimization module and an execution module, the transmission data acquisition module is divided into a channel characteristic unit and a transmission signal unit, wherein the channel characteristic unit is used for collecting multipath fading data and channel data, the transmission signal unit is used for collecting the signal-to-noise ratio of a transmission signal, and the channel characteristic processing module is divided into a multipath fading processing unit and a channel capacity processing unit. According to the system, a data acquisition technology and a neural network algorithm are closely combined with a modern information technology, multipath fading data and channel data are accurately captured, a channel monitoring model is constructed in combination with the neural network algorithm, and real-time and comprehensive monitoring on multipath fading and channel capacity abnormity of a channel is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of wireless data transmission, and in particular to an uplink single-carrier subsystem in a heterogeneous MIMO channel environment. Background Art

[0002] In the field of wireless communications, with the continuous development of wireless communication technology, IMT-Advanced systems have emerged. Against this backdrop, heterogeneous MIMO channel environments have become an important scenario in modern wireless communication systems. Most current Gbit transmission systems use the transmission technology of 100M systems. Open-loop MIMO technology requires extremely complex maximum likelihood detection under different channel conditions, resulting in a sharp increase in cost, volume, and processing power consumption. In addition, the heterogeneous MIMO channel environment is highly complex, affecting the data transmission performance of the uplink single-carrier subsystem. In order to break through the existing technical bottleneck and improve the transmission efficiency and reliability of the uplink, the uplink single-carrier subsystem in the heterogeneous MIMO channel environment needs to adopt advanced signal processing algorithms and technologies to cope with the complex channel environment and interference. As a result, the uplink single-carrier subsystem in the heterogeneous MIMO channel environment has emerged.

[0003] Although the existing technology has made great progress in the uplink single-carrier sub-field in the heterogeneous MIMO channel environment, there are still some problems that need to be optimized. The heterogeneous MIMO channel environment causes inconsistent channel characteristics for different users. The existing technology is difficult to take corresponding measures based on different channel characteristics, which in turn causes problems such as channel multipath fading and abnormal channel capacity, resulting in a decrease in the signal transmission performance of the uplink single-carrier subsystem. Summary of the Invention

[0004] To achieve the above objectives, the present invention is implemented through the following technical solutions: an uplink single-carrier subsystem in a heterogeneous MIMO channel environment includes a transmission data acquisition module, a preprocessing module, a channel characteristic processing module, a channel monitoring module, a channel optimization module and an execution module, wherein each module is communicatively connected;

[0005] The transmission data acquisition module is divided into a channel characteristic unit and a transmission signal unit. The channel characteristic unit is used to collect multipath fading data and channel data, and the transmission signal unit is used to collect the signal-to-noise ratio of the transmission signal, providing data preparation for the work of subsequent modules.

[0006] The preprocessing module preprocesses the collected data and calculates the multipath delay spread value using the delay of the signal propagating along different paths to the receiving end, providing data support for obtaining the multipath delay spread value for the multipath fading degree of the channel;

[0007] The channel characteristic processing module is divided into a multipath fading processing unit and a channel capacity processing unit, which evaluates the impact of various pre-processed data on channel characteristics and realizes the monitoring of channel multipath fading and channel capacity anomalies;

[0008] The channel monitoring module uses a neural network algorithm to construct a channel monitoring model;

[0009] The channel optimization module designs an uplink single-carrier sub-channel optimization unit, improves the uplink single-carrier sub-channel optimization unit, combines the output results of the channel monitoring model, and takes corresponding measures to optimize the channel characteristics, thereby solving the problem that the channel characteristics of different users are inconsistent due to the heterogeneous MIMO channel environment. The existing technology is difficult to take corresponding measures according to different channel characteristics, resulting in a decrease in the signal transmission performance of the uplink single-carrier subsystem.

[0010] A further improvement of the technical solution of the present invention is that the process of the transmission data acquisition module acquiring multipath fading data, channel data and signal-to-noise ratio of the transmission signal includes:

[0011] A1. The multipath fading data includes signal fading amplitude, signal fading duration, total signal transmission time, and signal transmission delay along different paths, and the channel data is channel bandwidth;

[0012] A2. The channel characteristic unit collects multipath fading data and channel data in the following process:

[0013] Set the spectrum analyzer parameters, calibrate the spectrum analyzer, record the signal amplitude at different time points, monitor the signal amplitude changes, use the signal amplitude during normal signal transmission as the reference amplitude, and based on the monitored signal amplitude changes, record the signal amplitude when the signal fades. Calculate the difference between the reference amplitude and the signal amplitude when the signal fades to obtain the signal fading amplitude.

[0014] Turn on the fading meter, record the signal fading in real time, mark the time period when the signal amplitude is lower than the reference amplitude, obtain the signal fading duration, and use an oscilloscope to measure the total signal transmission time;

[0015] Set the center frequency of the channel detector to match the center frequency of the transmission signal, turn on the channel detector, and send out a detection signal. The detection signal is transmitted along different paths, and the transmission time is recorded. Based on the transmission speed of the detection signal, the transmission delay of the detection signal along each path is calculated to obtain the transmission delay of the signal along different paths.

[0016] Connect a spectrum analyzer to the channel to be measured, set the spectrum analyzer parameters, measure the channel bandwidth, calculate the average value of the measured channel bandwidth, and obtain the channel bandwidth;

[0017] A3, the process of the transmission signal unit collecting the signal-to-noise ratio of the transmission signal is as follows:

[0018] Set the spectrum analyzer parameters, use the spectrum analyzer to measure the signal power and noise power, calculate the signal-to-noise ratio using the spectrum analyzer, and read the signal-to-noise ratio value from the spectrum analyzer display to obtain the signal-to-noise ratio of the transmitted signal.

[0019] A further improvement of the technical solution of the present invention is that the preprocessing module preprocesses the collected data and calculates the multipath delay spread value by using the delay of the signal propagating along different paths to the receiving end, including:

[0020] Perform data cleaning on multipath fading data, channel data, and the signal-to-noise ratio of the transmission signal to remove outliers and duplicate values;

[0021] The maximum and minimum delays of the signal along different paths are extracted from the delays of the signal along different paths. The multipath delay spread value is obtained by calculating the difference between the maximum delay and the minimum delay of the signal along different paths.

[0022] A further improvement of the technical solution of the present invention is that the channel characteristic processing module is divided into a multipath fading processing unit and a channel capacity processing unit, and the process of evaluating the impact of the pre-processed data on the channel characteristics includes:

[0023] The multipath fading processing unit is used to respectively obtain the multipath fading degree of the channel from the multipath delay spread value, the signal fading amplitude and the signal fading duration; the channel capacity processing unit calculates the channel capacity to obtain the influence of the channel bandwidth on the channel capacity.

[0024] A further improvement of the technical solution of the present invention is that the multipath fading processing unit obtains the multipath delay spread value, the signal fading amplitude and the signal fading duration for the multipath fading degree of the channel, respectively, including:

[0025] Set the multipath delay spread threshold range, which includes 0-1 microsecond, 1 microsecond-10 microseconds, and greater than 10 microseconds. When the multipath delay spread value is between 0 and 1 microsecond, the multipath delay spread value indicates a low multipath fading degree for the channel; when the multipath delay spread value is between 1 microsecond and 10 microseconds, the multipath delay spread value indicates a medium multipath fading degree for the channel; and when the multipath delay spread value is greater than 10 microseconds, the multipath delay spread value indicates a high multipath fading degree for the channel.

[0026] Set the signal fading amplitude threshold range, which includes 0~3dB, 3dB~10dB, and greater than 10dB. When the signal fading amplitude is between 0~3dB, the signal fading amplitude is low multipath fading for the channel; when the signal fading amplitude is between 3dB~10dB, the signal fading amplitude is medium multipath fading for the channel; when the signal fading amplitude is greater than 10dB, the signal fading amplitude is high multipath fading for the channel;

[0027] Calculate the proportion of signal fading duration in the total signal transmission time and set a threshold range for the proportion of signal fading duration in the total signal transmission time. The threshold ranges include 0-10%, 10%-30%, and more than 30%. When the proportion of signal fading duration in the total signal transmission time is between 0-10%, the signal fading duration indicates a low multipath fading degree for the channel; when the proportion of signal fading duration in the total signal transmission time is between 10%-30%, the signal fading duration indicates a medium multipath fading degree for the channel; and when the proportion of signal fading duration in the total signal transmission time exceeds 30%, the signal fading duration indicates a high multipath fading degree for the channel.

[0028] A further improvement of the technical solution of the present invention is that the process of the channel capacity processing unit calculating the channel capacity and obtaining the degree of influence of the channel bandwidth on the channel capacity includes:

[0029] According to Shannon's theorem, the process of calculating channel capacity using channel bandwidth and the signal-to-noise ratio of the transmitted signal is as follows:

[0030]

[0031] Where C is the channel capacity, B is the channel bandwidth, is the signal-to-noise ratio of the transmitted signal;

[0032] Keeping the signal-to-noise ratio of the transmitted signal unchanged, changing the channel bandwidth, and calculating the corresponding channel capacity using Shannon's theorem, draw the channel bandwidth-channel capacity curve with the channel bandwidth as the horizontal axis and the channel capacity as the vertical axis. Observe and calculate the slope of the channel bandwidth-channel capacity curve. The calculation formula is: , obtain the slope of the channel bandwidth-channel capacity curve, and divide the degree of influence of the channel bandwidth on the channel capacity according to the slope of the channel bandwidth-channel capacity curve;

[0033] When the slope of the channel bandwidth-channel capacity curve is between 0 and 0.1, the channel bandwidth has a low impact on the channel capacity; when the slope of the channel bandwidth-channel capacity curve is between 0.1 and 3.5, the channel bandwidth has a medium impact on the channel capacity; when the slope of the channel bandwidth-channel capacity curve is greater than 3.5, the channel bandwidth has a high impact on the channel capacity.

[0034] A further improvement of the technical solution of the present invention is that the channel monitoring module uses a neural network algorithm to construct a channel monitoring model, including the following steps:

[0035] A neural network model was constructed using a neural network algorithm. The multipath delay spread value and its impact on the multipath fading degree of the channel, the signal fading amplitude and its impact on the multipath fading degree of the channel, the signal fading duration and its impact on the multipath fading degree of the channel, and the channel bandwidth and its impact on the channel capacity were used as data sets. The data sets were divided into training and test sets in a ratio of 7:3. MLP was selected as the neural network structure. The input layer included four neurons, which received the multipath delay spread value, signal fading amplitude, signal fading duration, and channel bandwidth. The hidden layer was configured with the MSE function. The output layer included four neurons, which output the impact of the multipath delay spread value on the multipath fading degree of the channel, the impact of the signal fading amplitude on the multipath fading degree of the channel, the impact of the signal fading duration on the multipath fading degree of the channel, and the impact of the channel bandwidth on the channel capacity.

[0036] Input the training set data into the neural network model, set the learning rate to 0.01, and the number of iterative training times to 1000. The training process includes forward propagation and back propagation, wherein the forward propagation is used to calculate the predicted output data, and the back propagation is used to update the weights and biases of the model. Through repeated iterative training, the nonlinear relationship between the multipath delay spread value and the multipath delay spread value and the multipath fading degree of the channel, the nonlinear relationship between the signal fading amplitude and the signal fading amplitude and the multipath fading degree of the channel, the nonlinear relationship between the signal fading duration and the signal fading duration and the multipath fading degree of the channel, and the nonlinear relationship between the channel bandwidth and the influence of the channel bandwidth on the channel capacity are learned until the set number of iterative training times is reached, and the trained neural network model is obtained;

[0037] The test set data is input into the trained neural network model, and the MSE function is used to evaluate the error between the output value of the neural network model and the actual value. The parameters of the neural network model are adjusted according to the evaluation results, the performance of the neural network model is optimized, and the channel monitoring model is obtained.

[0038] A further improvement of the technical solution of the present invention is that: the process of designing the uplink single-carrier sub-channel optimization unit in the channel optimization module includes:

[0039] The uplink single-carrier channel optimization unit consists of a transmitter and a receiver;

[0040] The transmitter includes an encoder, a modulator, a precoding module, a power amplifier, and a transmitting antenna. The encoder is used to encode the transmission signal and add redundant information to improve anti-interference capability. The modulator is used to modulate the encoded transmission signal onto a single carrier. The precoding module is used to pre-process the transmission signal according to the channel state. The power amplifier is used to increase the transmission signal power. The transmitting antenna is used to transmit the pre-processed transmission signal.

[0041] The receiver includes a low-noise amplifier, a demodulator, a decoder, an equalizer and a receiving antenna. The low-noise amplifier is used to amplify the transmission signal, the demodulator is used to demodulate the transmission signal, the decoder is used to restore the transmission signal, the equalizer is used to reduce the inter-code interference caused by multipath fading, and the receiving antenna is used to receive the transmission signal.

[0042] A further improvement of the technical solution of the present invention is that: the channel optimization module improves the uplink single-carrier channel optimization unit to include:

[0043] An interleaving technique is configured for the encoder in the uplink single-carrier channel optimization unit transmitter to perform interleaving processing on continuous signals;

[0044] The uplink single-carrier sub-channel optimization unit receiver is configured with diversity reception technology and a soft decision algorithm, and the equalizer in the uplink single-carrier sub-channel optimization unit receiver is configured with a minimum mean square error equalization algorithm. The equalizer coefficient is adjusted according to the multipath fading degree of the channel based on the multipath delay spread value to compensate for the inter-symbol interference caused by the multipath delay spread.

[0045] A further improvement of the technical solution of the present invention is that the channel optimization module, in combination with the output of the channel monitoring model, takes corresponding measures to optimize the channel characteristics, including:

[0046] The multipath delay spread value, signal fading amplitude, signal fading duration and channel bandwidth are input into the channel monitoring model respectively, and the channel monitoring model outputs the influence of the multipath delay spread value on the multipath fading degree of the channel, the influence of the signal fading amplitude on the multipath fading degree of the channel, the influence of the signal fading duration on the multipath fading degree of the channel and the influence of the channel bandwidth on the channel capacity;

[0047] When the multipath delay spread value for the channel is low, the channel's multipath fading is less affected by the multipath delay spread value, and the multipath delay spread value is continuously monitored. When the multipath delay spread value for the channel is medium, the transmitter's precoding module constructs a precoding matrix based on the multipath delay spread value to disperse the energy of the multipath signal in the time dimension and reduce the inter-symbol interference caused by the multipath delay spread. When the multipath delay spread value for the channel is high, the receiver's equalizer uses the minimum mean square error equalization algorithm. The equalizer adjusts its own parameters to compensate for the inter-symbol interference caused by the multipath delay spread.

[0048] When the signal fading amplitude is low for the channel, the multipath fading of the channel is less affected by the signal fading amplitude, and the signal fading amplitude is continuously monitored. When the signal fading amplitude is medium for the channel, the transmitter's power amplifier adjusts the power of the transmitted signal according to the signal fading amplitude. When the signal fading amplitude is between 3dB and 6dB, the power amplifier is used to reduce the transmit power. When the signal fading amplitude is between 6dB and 10dB, the power amplifier is used to increase the transmit power. When the signal fading amplitude is high for the channel, diversity reception technology is used in the receiver, using antennas with different polarization modes to receive signals. Since the signals received by antennas with different polarization modes are independent, the signals received by antennas with different polarization modes are combined and processed to reduce the impact of the signal fading amplitude.

[0049] When the signal fading duration is low for the channel, the multipath fading of the channel is less affected by the signal fading duration, and the signal fading duration is continuously monitored. When the signal fading duration is medium for the channel, the encoder in the scheduling transmitter uses interleaving technology to interleave continuous signals, spreading the continuous signals in time, and uses information from the non-faded signal to correct the fading signal. When the signal fading duration is high for the channel, the decoder in the scheduling receiver uses a soft decision algorithm to extract the reliability information of the received signal and encode the reliability information.

[0050] When the channel bandwidth has a low impact on the channel capacity, the channel capacity is less affected by the channel bandwidth and the channel bandwidth is continuously monitored. When the channel bandwidth has a medium impact on the channel capacity, the modulator in the transmitter adjusts the modulation mode according to the slope of the channel bandwidth-channel capacity curve. When the slope of the channel bandwidth-channel capacity curve is between 0.1 and 1, high-order modulation is used. When the slope of the channel bandwidth-channel capacity curve is between 1 and 3.5, low-order modulation is used. When the channel bandwidth has a high impact on the channel capacity, the equalizer in the receiver adjusts the number of taps according to the channel bandwidth. When the slope of the channel bandwidth-channel capacity curve is between 0.1 and 1, the number of taps is increased to reduce inter-symbol interference. When the slope of the channel bandwidth-channel capacity curve is between 1 and 3.5, the number of taps is reduced to weaken overcompensation. The demodulator is also scheduled to adjust the sampling frequency to match the sampling frequency with the channel bandwidth to avoid spectrum aliasing.

[0051] The beneficial effects of the present invention are as follows: compared with the traditional uplink single-carrier subsystem in a heterogeneous MIMO channel environment, the data acquisition technology and neural network algorithm in the system of the present invention are closely combined with modern information technology, accurately capturing multipath fading data and channel data, obtaining multipath delay spread value and channel capacity by calculation, obtaining the multipath delay spread value, signal fading amplitude and signal fading duration on the multipath fading degree of the channel and the influence of channel bandwidth on channel capacity by related data processing, and constructing a channel monitoring model in combination with the neural network algorithm to achieve the multipath fading and channel capacity anomaly of the channel. Real-time and comprehensive monitoring solves the problem of inconsistent channel characteristics of different users caused by heterogeneous MIMO channel environments. Existing technologies make it difficult to take corresponding measures to deal with different channel characteristics, which in turn causes channel multipath fading and abnormal channel capacity, leading to a decline in the signal transmission performance of the uplink single-carrier subsystem. This ensures that the method in the present invention can refine the dynamic monitoring standard for the uplink single-carrier subsystem in the heterogeneous MIMO channel environment within a more precise range, making the monitored data a more accurate indicator under the same conditions. The development and application of this method significantly enhances the level of intelligence during the operation of the uplink single-carrier subsystem in the heterogeneous MIMO channel environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments described in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0053] Figure 1 This is a block diagram of an uplink single-carrier subsystem in a heterogeneous MIMO channel environment according to the present invention. DETAILED DESCRIPTION

[0054] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0055] like Figure 1 As shown, the present invention provides an uplink single-carrier subsystem in a heterogeneous MIMO channel environment, including a transmission data acquisition module, a preprocessing module, a channel characteristic processing module, a channel monitoring module, a channel optimization module and an execution module, wherein each module is communicatively connected;

[0056] The transmission data acquisition module is divided into a channel characteristic unit and a transmission signal unit. The channel characteristic unit is used to collect multipath fading data and channel data, and the transmission signal unit is used to collect the signal-to-noise ratio of the transmission signal, providing data preparation for the work of subsequent modules.

[0057] The preprocessing module preprocesses the collected data and calculates the multipath delay spread value using the delay of the signal propagating along different paths to the receiving end, providing data support for obtaining the multipath delay spread value and the multipath fading degree of the channel;

[0058] The channel characteristic processing module is divided into a multipath fading processing unit and a channel capacity processing unit. It evaluates the impact of various pre-processed data on channel characteristics and realizes the monitoring of channel multipath fading and channel capacity anomalies.

[0059] The channel monitoring module uses a neural network algorithm to build a channel monitoring model;

[0060] The channel optimization module designs an uplink single-carrier sub-channel optimization unit, improves the uplink single-carrier sub-channel optimization unit, combines the output results of the channel monitoring model, and takes corresponding measures to optimize the channel characteristics. It solves the problem that the channel characteristics of different users are inconsistent due to the heterogeneous MIMO channel environment. The existing technology is difficult to take corresponding measures according to different channel characteristics, resulting in a decrease in the signal transmission performance of the uplink single-carrier subsystem.

[0061] Preferably, the process of the transmission data acquisition module collecting multipath fading data, channel data and signal-to-noise ratio of the transmission signal includes:

[0062] A1. The multipath fading data includes signal fading amplitude, signal fading duration, total signal transmission time, and signal transmission delay along different paths, and the channel data is channel bandwidth;

[0063] A2. The channel characteristic unit collects multipath fading data and channel data in the following process:

[0064] Set the spectrum analyzer parameters, calibrate the spectrum analyzer, record the signal amplitude at different time points, monitor the signal amplitude changes, use the signal amplitude during normal signal transmission as the reference amplitude, and based on the monitored signal amplitude changes, record the signal amplitude when the signal fades. Calculate the difference between the reference amplitude and the signal amplitude when the signal fades to obtain the signal fading amplitude.

[0065] Turn on the fading meter, record the signal fading in real time, mark the time period when the signal amplitude is lower than the reference amplitude, obtain the signal fading duration, and use an oscilloscope to measure the total signal transmission time;

[0066] Set the center frequency of the channel detector to match the center frequency of the transmission signal, turn on the channel detector, and send out a detection signal. The detection signal is transmitted along different paths, and the transmission time is recorded. Based on the transmission speed of the detection signal, the transmission delay of the detection signal along each path is calculated to obtain the transmission delay of the signal along different paths.

[0067] Connect a spectrum analyzer to the channel to be measured, set the spectrum analyzer parameters, measure the channel bandwidth, calculate the average value of the measured channel bandwidth, and obtain the channel bandwidth;

[0068] A3, the transmission signal unit, the process of collecting the signal-to-noise ratio of the transmission signal is as follows:

[0069] Set the spectrum analyzer parameters, use the spectrum analyzer to measure the signal power and noise power, calculate the signal-to-noise ratio using the spectrum analyzer, and read the signal-to-noise ratio value from the spectrum analyzer display to obtain the signal-to-noise ratio of the transmitted signal.

[0070] Preferably, the preprocessing module preprocesses the collected data and calculates the multipath delay spread value by using the delay of the signal propagating along different paths to the receiving end, including:

[0071] Perform data cleaning on multipath fading data, channel data, and the signal-to-noise ratio of the transmission signal to remove outliers and duplicate values;

[0072] The maximum and minimum delays of the signal along different paths are extracted from the delays of the signal along different paths. The multipath delay spread value is obtained by calculating the difference between the maximum delay and the minimum delay of the signal along different paths.

[0073] Preferably, the channel characteristic processing module is divided into a multipath fading processing unit and a channel capacity processing unit. The process of evaluating the influence of various pre-processed data on the channel characteristics includes:

[0074] Among them, the multipath fading processing unit is used to respectively obtain the multipath fading degree of the channel from the multipath delay spread value, signal fading amplitude and signal fading duration; the channel capacity processing unit calculates the channel capacity and is used to obtain the influence of the channel bandwidth on the channel capacity.

[0075] Preferably, the multipath fading processing unit obtains the multipath delay spread value, the signal fading amplitude, and the signal fading duration for the multipath fading degree of the channel, respectively, including:

[0076] Set the multipath delay spread threshold range, which includes 0-1 microsecond, 1 microsecond-10 microseconds, and greater than 10 microseconds. When the multipath delay spread value is between 0 and 1 microsecond, the multipath delay spread value indicates a low multipath fading degree for the channel; when the multipath delay spread value is between 1 microsecond and 10 microseconds, the multipath delay spread value indicates a medium multipath fading degree for the channel; and when the multipath delay spread value is greater than 10 microseconds, the multipath delay spread value indicates a high multipath fading degree for the channel.

[0077] Set the signal fading amplitude threshold range, which includes 0~3dB, 3dB~10dB, and greater than 10dB. When the signal fading amplitude is between 0~3dB, the signal fading amplitude is low multipath fading for the channel; when the signal fading amplitude is between 3dB~10dB, the signal fading amplitude is medium multipath fading for the channel; when the signal fading amplitude is greater than 10dB, the signal fading amplitude is high multipath fading for the channel;

[0078] Calculate the proportion of signal fading duration in the total signal transmission time and set a threshold range for the proportion of signal fading duration in the total signal transmission time. The threshold ranges include 0-10%, 10%-30%, and more than 30%. When the proportion of signal fading duration in the total signal transmission time is between 0-10%, the signal fading duration indicates a low multipath fading degree for the channel; when the proportion of signal fading duration in the total signal transmission time is between 10%-30%, the signal fading duration indicates a medium multipath fading degree for the channel; and when the proportion of signal fading duration in the total signal transmission time exceeds 30%, the signal fading duration indicates a high multipath fading degree for the channel.

[0079] Preferably, the process of the channel capacity processing unit calculating the channel capacity and obtaining the degree of influence of the channel bandwidth on the channel capacity includes:

[0080] According to Shannon's theorem, the process of calculating channel capacity using channel bandwidth and the signal-to-noise ratio of the transmitted signal is as follows:

[0081]

[0082] Where C is the channel capacity, B is the channel bandwidth, is the signal-to-noise ratio of the transmitted signal;

[0083] Keeping the signal-to-noise ratio of the transmitted signal unchanged, changing the channel bandwidth, and calculating the corresponding channel capacity using Shannon's theorem, draw the channel bandwidth-channel capacity curve with the channel bandwidth as the horizontal axis and the channel capacity as the vertical axis. Observe and calculate the slope of the channel bandwidth-channel capacity curve. The calculation formula is: , obtain the slope of the channel bandwidth-channel capacity curve, and divide the degree of influence of the channel bandwidth on the channel capacity according to the slope of the channel bandwidth-channel capacity curve;

[0084] When the slope of the channel bandwidth-channel capacity curve is between 0 and 0.1, the channel bandwidth has a low impact on the channel capacity; when the slope of the channel bandwidth-channel capacity curve is between 0.1 and 3.5, the channel bandwidth has a medium impact on the channel capacity; when the slope of the channel bandwidth-channel capacity curve is greater than 3.5, the channel bandwidth has a high impact on the channel capacity.

[0085] Preferably, the channel monitoring module uses a neural network algorithm to construct a channel monitoring model, including:

[0086] A neural network model was constructed using a neural network algorithm. The multipath delay spread value and its impact on the multipath fading degree of the channel, the signal fading amplitude and its impact on the multipath fading degree of the channel, the signal fading duration and its impact on the multipath fading degree of the channel, and the channel bandwidth and its impact on the channel capacity were used as data sets. The data sets were divided into training and test sets in a ratio of 7:3. MLP was selected as the neural network structure. The input layer included four neurons, which received the multipath delay spread value, signal fading amplitude, signal fading duration, and channel bandwidth. The hidden layer was configured with the MSE function. The output layer included four neurons, which output the impact of the multipath delay spread value on the multipath fading degree of the channel, the impact of the signal fading amplitude on the multipath fading degree of the channel, the impact of the signal fading duration on the multipath fading degree of the channel, and the impact of the channel bandwidth on the channel capacity.

[0087] Input the training set data into the neural network model, set the learning rate to 0.01, and the number of iterative training times to 1000. The training process includes forward propagation and back propagation, wherein the forward propagation is used to calculate the predicted output data, and the back propagation is used to update the weights and biases of the model. Through repeated iterative training, the nonlinear relationship between the multipath delay spread value and the multipath delay spread value and the multipath fading degree of the channel, the nonlinear relationship between the signal fading amplitude and the signal fading amplitude and the multipath fading degree of the channel, the nonlinear relationship between the signal fading duration and the signal fading duration and the multipath fading degree of the channel, and the nonlinear relationship between the channel bandwidth and the influence of the channel bandwidth on the channel capacity are learned until the set number of iterative training times is reached, and the trained neural network model is obtained;

[0088] The test set data is input into the trained neural network model, and the MSE function is used to evaluate the error between the output value of the neural network model and the actual value. The parameters of the neural network model are adjusted according to the evaluation results, the performance of the neural network model is optimized, and the channel monitoring model is obtained.

[0089] Preferably, the channel optimization module designs an uplink single-carrier sub-channel optimization unit, comprising:

[0090] The uplink single-carrier channel optimization unit consists of a transmitter and a receiver;

[0091] The transmitter includes an encoder, a modulator, a precoding module, a power amplifier, and a transmitting antenna. The encoder is used to encode the transmission signal and add redundant information to improve anti-interference capability. The modulator is used to modulate the encoded transmission signal onto a single carrier. The precoding module is used to pre-process the transmission signal according to the channel state. The power amplifier is used to increase the transmission signal power. The transmitting antenna is used to transmit the pre-processed transmission signal.

[0092] The receiver includes a low-noise amplifier, a demodulator, a decoder, an equalizer and a receiving antenna. The low-noise amplifier is used to amplify the transmission signal, the demodulator is used to demodulate the transmission signal, the decoder is used to restore the transmission signal, the equalizer is used to reduce the inter-code interference caused by multipath fading, and the receiving antenna is used to receive the transmission signal.

[0093] Preferably, the channel optimization module improves the uplink single-carrier channel optimization unit and includes:

[0094] An interleaving technique is configured for the encoder in the uplink single-carrier channel optimization unit transmitter to perform interleaving processing on continuous signals;

[0095] The uplink single-carrier sub-channel optimization unit receiver is configured with diversity reception technology and a soft decision algorithm, and the equalizer in the uplink single-carrier sub-channel optimization unit receiver is configured with a minimum mean square error equalization algorithm. The equalizer coefficient is adjusted according to the multipath fading degree of the channel based on the multipath delay spread value to compensate for the inter-symbol interference caused by the multipath delay spread.

[0096] Preferably, the channel optimization module, in combination with the output result of the channel monitoring model, takes corresponding measures to optimize the channel characteristics, including:

[0097] The multipath delay spread value, signal fading amplitude, signal fading duration and channel bandwidth are input into the channel monitoring model respectively, and the channel monitoring model outputs the influence of the multipath delay spread value on the multipath fading degree of the channel, the influence of the signal fading amplitude on the multipath fading degree of the channel, the influence of the signal fading duration on the multipath fading degree of the channel and the influence of the channel bandwidth on the channel capacity;

[0098] When the multipath delay spread value for the channel is low, the channel's multipath fading is less affected by the multipath delay spread value, and the multipath delay spread value is continuously monitored. When the multipath delay spread value for the channel is medium, the transmitter's precoding module constructs a precoding matrix based on the multipath delay spread value to disperse the energy of the multipath signal in the time dimension and reduce the inter-symbol interference caused by the multipath delay spread. When the multipath delay spread value for the channel is high, the receiver's equalizer uses the minimum mean square error equalization algorithm. The equalizer adjusts its own parameters to compensate for the inter-symbol interference caused by the multipath delay spread.

[0099] When the signal fading amplitude is low for the channel, the multipath fading of the channel is less affected by the signal fading amplitude, and the signal fading amplitude is continuously monitored. When the signal fading amplitude is medium for the channel, the transmitter's power amplifier adjusts the power of the transmitted signal according to the signal fading amplitude. When the signal fading amplitude is between 3dB and 6dB, the power amplifier is used to reduce the transmit power. When the signal fading amplitude is between 6dB and 10dB, the power amplifier is used to increase the transmit power. When the signal fading amplitude is high for the channel, diversity reception technology is used in the receiver, using antennas with different polarization modes to receive signals. Since the signals received by antennas with different polarization modes are independent, the signals received by antennas with different polarization modes are combined and processed to reduce the impact of the signal fading amplitude.

[0100] When the signal fading duration is low for the channel, the multipath fading of the channel is less affected by the signal fading duration, and the signal fading duration is continuously monitored. When the signal fading duration is medium for the channel, the encoder in the scheduling transmitter uses interleaving technology to interleave continuous signals, spreading the continuous signals in time, and uses information from the non-faded signal to correct the fading signal. When the signal fading duration is high for the channel, the decoder in the scheduling receiver uses a soft decision algorithm to extract the reliability information of the received signal and encode the reliability information.

[0101] When the channel bandwidth has a low impact on the channel capacity, the channel capacity is less affected by the channel bandwidth and the channel bandwidth is continuously monitored. When the channel bandwidth has a medium impact on the channel capacity, the modulator in the transmitter adjusts the modulation mode according to the slope of the channel bandwidth-channel capacity curve. When the slope of the channel bandwidth-channel capacity curve is between 0.1 and 1, high-order modulation is used. When the slope of the channel bandwidth-channel capacity curve is between 1 and 3.5, low-order modulation is used. When the channel bandwidth has a high impact on the channel capacity, the equalizer in the receiver adjusts the number of taps according to the channel bandwidth. When the slope of the channel bandwidth-channel capacity curve is between 0.1 and 1, the number of taps is increased to reduce inter-symbol interference. When the slope of the channel bandwidth-channel capacity curve is between 1 and 3.5, the number of taps is reduced to weaken overcompensation. The demodulator is also scheduled to adjust the sampling frequency to match the sampling frequency with the channel bandwidth to avoid spectrum aliasing.

[0102] First, a spectrum analyzer is used to collect the signal fading amplitude, channel bandwidth and signal-to-noise ratio of the transmitted signal. The signal fading duration, total signal transmission time and signal transmission delay along different paths are collected respectively through a fading meter, an oscilloscope and a channel detector. Secondly, the collected data is preprocessed and the multipath delay spread value is calculated using the delay of the signal propagating along different paths to the receiving end. Then, the multipath delay spread value is used to set the multipath delay spread value threshold range and obtain the multipath fading degree of the multipath delay spread value to the channel. The signal fading amplitude threshold range is set and the signal fading amplitude threshold range is used to obtain the multipath fading degree of the channel to the signal fading amplitude. The proportion of the signal fading duration in the total signal transmission time is calculated and the proportion of the signal fading duration in the total signal transmission time is set. The influence of signal fading duration on the multipath fading degree of the channel is obtained by using the proportion threshold range; according to Shannon's theorem, the channel capacity is calculated using the channel bandwidth and the signal-to-noise ratio of the transmitted signal to obtain the influence of channel bandwidth on the channel capacity; then, a channel monitoring model is constructed using a neural network algorithm to realize that the channel monitoring model sequentially inputs the multipath delay spread value, signal fading amplitude, signal fading duration and channel bandwidth, and correspondingly outputs the influence of multipath delay spread value on the multipath fading degree of the channel, signal fading amplitude on the multipath fading degree of the channel, signal fading duration on the multipath fading degree of the channel and channel bandwidth on the channel capacity; then, the uplink single-carrier sub-channel optimization unit is designed and optimized; finally, corresponding measures are taken to optimize the channel characteristics based on the output results of the channel monitoring model.

[0103] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. The uplink single-carrier subsystem in a heterogeneous MIMO channel environment includes a transmission data acquisition module, a preprocessing module, a channel characteristic processing module, a channel monitoring module, a channel optimization module, and an execution module, wherein: The modules are connected in communication, characterized by: The transmission data acquisition module is divided into a channel characteristic unit and a transmission signal unit, wherein the channel characteristic unit is used to collect multipath fading data and channel data, and the transmission signal unit is used to collect the signal-to-noise ratio of the transmission signal; The preprocessing module preprocesses the collected data and calculates the multipath delay spread value using the delay of the signal propagating along different paths to the receiving end; The channel characteristic processing module is divided into a multipath fading processing unit and a channel capacity processing unit, which evaluates the impact of various pre-processed data on channel characteristics; The channel monitoring module uses a neural network algorithm to construct a channel monitoring model; The channel optimization module designs an uplink single-carrier sub-channel optimization unit, improves the uplink single-carrier sub-channel optimization unit, and takes corresponding measures to optimize channel characteristics in combination with the output results of the channel monitoring model.

2. The uplink single-carrier subsystem in a heterogeneous MIMO channel environment according to claim 1, characterized in that: The process of the transmission data acquisition module collecting multipath fading data, channel data and signal-to-noise ratio of the transmission signal includes: A1. The multipath fading data includes signal fading amplitude, signal fading duration, total signal transmission time, and signal transmission delay along different paths, and the channel data is channel bandwidth; A2. The channel characteristic unit collects multipath fading data and channel data in the following process: Set the spectrum analyzer parameters, calibrate the spectrum analyzer, record the signal amplitude at different time points, monitor the signal amplitude changes, use the signal amplitude during normal signal transmission as the reference amplitude, and based on the monitored signal amplitude changes, record the signal amplitude when the signal fades. Calculate the difference between the reference amplitude and the signal amplitude when the signal fades to obtain the signal fading amplitude. Turn on the fading meter, record the signal fading in real time, mark the time period when the signal amplitude is lower than the reference amplitude, obtain the signal fading duration, and use an oscilloscope to measure the total signal transmission time; Set the center frequency of the channel detector to match the center frequency of the transmission signal, turn on the channel detector, and send out a detection signal. The detection signal is transmitted along different paths, and the transmission time is recorded. Based on the transmission speed of the detection signal, the transmission delay of the detection signal along each path is calculated to obtain the transmission delay of the signal along different paths. Connect a spectrum analyzer to the channel to be measured, set the spectrum analyzer parameters, measure the channel bandwidth, calculate the average value of the measured channel bandwidth, and obtain the channel bandwidth; A3, the process of the transmission signal unit collecting the signal-to-noise ratio of the transmission signal is as follows: Set the spectrum analyzer parameters, use the spectrum analyzer to measure the signal power and noise power, calculate the signal-to-noise ratio using the spectrum analyzer, and read the signal-to-noise ratio value from the spectrum analyzer display to obtain the signal-to-noise ratio of the transmitted signal.

3. The uplink single-carrier subsystem in a heterogeneous MIMO channel environment according to claim 2, characterized in that: The preprocessing module preprocesses the collected data and calculates the multipath delay spread value by using the delay of the signal propagating along different paths to the receiving end. The process includes: Perform data cleaning on multipath fading data, channel data, and the signal-to-noise ratio of the transmission signal to remove outliers and duplicate values; The maximum and minimum delays of the signal along different paths are extracted from the delays of the signal along different paths. The multipath delay spread value is obtained by calculating the difference between the maximum delay and the minimum delay of the signal along different paths.

4. The uplink single-carrier subsystem in a heterogeneous MIMO channel environment according to claim 3, characterized in that: The channel characteristic processing module is divided into a multipath fading processing unit and a channel capacity processing unit. The process of evaluating the impact of various pre-processed data on channel characteristics includes: The multipath fading processing unit is used to respectively obtain the multipath fading degree of the channel from the multipath delay spread value, the signal fading amplitude and the signal fading duration; the channel capacity processing unit calculates the channel capacity to obtain the influence of the channel bandwidth on the channel capacity.

5. The uplink single-carrier subsystem in a heterogeneous MIMO channel environment according to claim 4, characterized in that: The multipath fading processing unit obtains the multipath delay spread value, the signal fading amplitude, and the signal fading duration for the multipath fading degree of the channel, respectively, including: Set the multipath delay spread threshold range, which includes 0-1 microsecond, 1 microsecond-10 microseconds, and greater than 10 microseconds. When the multipath delay spread value is between 0 and 1 microsecond, the multipath delay spread value indicates a low multipath fading degree for the channel; when the multipath delay spread value is between 1 microsecond and 10 microseconds, the multipath delay spread value indicates a medium multipath fading degree for the channel; and when the multipath delay spread value is greater than 10 microseconds, the multipath delay spread value indicates a high multipath fading degree for the channel. Set the signal fading amplitude threshold range, which includes 0~3dB, 3dB~10dB, and greater than 10dB. When the signal fading amplitude is between 0~3dB, the signal fading amplitude is low multipath fading for the channel; when the signal fading amplitude is between 3dB~10dB, the signal fading amplitude is medium multipath fading for the channel; when the signal fading amplitude is greater than 10dB, the signal fading amplitude is high multipath fading for the channel; Calculate the proportion of signal fading duration in the total signal transmission time and set a threshold range for the proportion of signal fading duration in the total signal transmission time. The threshold ranges include 0-10%, 10%-30%, and more than 30%. When the proportion of signal fading duration in the total signal transmission time is between 0-10%, the signal fading duration indicates a low multipath fading degree for the channel; when the proportion of signal fading duration in the total signal transmission time is between 10%-30%, the signal fading duration indicates a medium multipath fading degree for the channel; and when the proportion of signal fading duration in the total signal transmission time exceeds 30%, the signal fading duration indicates a high multipath fading degree for the channel.

6. The uplink single-carrier subsystem in a heterogeneous MIMO channel environment according to claim 5, characterized in that: The process of the channel capacity processing unit calculating the channel capacity and obtaining the influence of the channel bandwidth on the channel capacity includes: According to Shannon's theorem, the process of calculating channel capacity using channel bandwidth and the signal-to-noise ratio of the transmitted signal is as follows: ， Where C is the channel capacity, B is the channel bandwidth, is the signal-to-noise ratio of the transmitted signal; Keeping the signal-to-noise ratio of the transmitted signal unchanged, changing the channel bandwidth, and calculating the corresponding channel capacity using Shannon's theorem, draw the channel bandwidth-channel capacity curve with the channel bandwidth as the horizontal axis and the channel capacity as the vertical axis. Observe and calculate the slope of the channel bandwidth-channel capacity curve. The calculation formula is: , obtain the slope of the channel bandwidth-channel capacity curve, and divide the degree of influence of the channel bandwidth on the channel capacity according to the slope of the channel bandwidth-channel capacity curve; When the slope of the channel bandwidth-channel capacity curve is between 0 and 0.1, the channel bandwidth has a low impact on the channel capacity; when the slope of the channel bandwidth-channel capacity curve is between 0.1 and 3.5, the channel bandwidth has a medium impact on the channel capacity; when the slope of the channel bandwidth-channel capacity curve is greater than 3.5, the channel bandwidth has a high impact on the channel capacity.

7. The uplink single-carrier subsystem in a heterogeneous MIMO channel environment according to claim 6, characterized in that: The channel monitoring module uses a neural network algorithm to construct a channel monitoring model, including the following steps: A neural network model was constructed using a neural network algorithm. The multipath delay spread value and its impact on the multipath fading degree of the channel, the signal fading amplitude and its impact on the multipath fading degree of the channel, the signal fading duration and its impact on the multipath fading degree of the channel, and the channel bandwidth and its impact on the channel capacity were used as data sets. The data sets were divided into training and test sets in a ratio of 7:

3. MLP was selected as the neural network structure. The input layer included four neurons, which received the multipath delay spread value, signal fading amplitude, signal fading duration, and channel bandwidth. The hidden layer was configured with the MSE function. The output layer included four neurons, which output the impact of the multipath delay spread value on the multipath fading degree of the channel, the impact of the signal fading amplitude on the multipath fading degree of the channel, the impact of the signal fading duration on the multipath fading degree of the channel, and the impact of the channel bandwidth on the channel capacity. Input the training set data into the neural network model, set the learning rate to 0.01, and the number of iterative training times to 1000. The training process includes forward propagation and back propagation, wherein the forward propagation is used to calculate the predicted output data, and the back propagation is used to update the weights and biases of the model. Through repeated iterative training, the nonlinear relationship between the multipath delay spread value and the multipath delay spread value and the multipath fading degree of the channel, the nonlinear relationship between the signal fading amplitude and the signal fading amplitude and the multipath fading degree of the channel, the nonlinear relationship between the signal fading duration and the signal fading duration and the multipath fading degree of the channel, and the nonlinear relationship between the channel bandwidth and the influence of the channel bandwidth on the channel capacity are learned until the set number of iterative training times is reached, and the trained neural network model is obtained; The test set data is input into the trained neural network model, and the MSE function is used to evaluate the error between the output value of the neural network model and the actual value. The parameters of the neural network model are adjusted according to the evaluation results, the performance of the neural network model is optimized, and the channel monitoring model is obtained.

8. The uplink single-carrier subsystem in a heterogeneous MIMO channel environment according to claim 7, characterized in that: The channel optimization module designs an uplink single-carrier channel optimization unit, including: The uplink single-carrier channel optimization unit consists of a transmitter and a receiver; The transmitter includes an encoder, a modulator, a precoding module, a power amplifier, and a transmitting antenna. The encoder is used to encode the transmission signal, the modulator is used to modulate the encoded transmission signal onto a single carrier, the precoding module is used to preprocess the transmission signal according to the channel state, the power amplifier is used to increase the transmission signal power, and the transmitting antenna is used to transmit the preprocessed transmission signal. The receiver includes a low-noise amplifier, a demodulator, a decoder, an equalizer and a receiving antenna. The low-noise amplifier is used to amplify the transmission signal, the demodulator is used to demodulate the transmission signal, the decoder is used to restore the transmission signal, the equalizer is used to reduce the inter-code interference caused by multipath fading, and the receiving antenna is used to receive the transmission signal.

9. The uplink single-carrier subsystem in a heterogeneous MIMO channel environment according to claim 8, characterized in that: The channel optimization module improves the uplink single-carrier channel optimization unit and includes: An interleaving technique is configured for the encoder in the uplink single-carrier channel optimization unit transmitter to perform interleaving processing on continuous signals; The uplink single-carrier sub-channel optimization unit receiver is configured with diversity reception technology and a soft decision algorithm, and the equalizer in the uplink single-carrier sub-channel optimization unit receiver is configured with a minimum mean square error equalization algorithm. The equalizer coefficient is adjusted according to the multipath fading degree of the channel based on the multipath delay spread value to compensate for the inter-symbol interference caused by the multipath delay spread.

10. The uplink single-carrier subsystem in a heterogeneous MIMO channel environment according to claim 9, characterized in that: The channel optimization module, in combination with the output of the channel monitoring model, takes corresponding measures to optimize the channel characteristics, including: The multipath delay spread value, signal fading amplitude, signal fading duration and channel bandwidth are input into the channel monitoring model respectively, and the channel monitoring model outputs the influence of the multipath delay spread value on the multipath fading degree of the channel, the influence of the signal fading amplitude on the multipath fading degree of the channel, the influence of the signal fading duration on the multipath fading degree of the channel and the influence of the channel bandwidth on the channel capacity; When the multipath delay spread value for the channel is low, the channel's multipath fading is less affected by the multipath delay spread value, and the multipath delay spread value is continuously monitored. When the multipath delay spread value for the channel is medium, the transmitter's precoding module constructs a precoding matrix based on the multipath delay spread value to disperse the energy of the multipath signal in the time dimension and reduce the inter-symbol interference caused by the multipath delay spread. When the multipath delay spread value for the channel is high, the receiver's equalizer uses the minimum mean square error equalization algorithm. The equalizer adjusts its own parameters to compensate for the inter-symbol interference caused by the multipath delay spread. When the signal fading amplitude is low for the channel, the multipath fading of the channel is less affected by the signal fading amplitude, and the signal fading amplitude is continuously monitored. When the signal fading amplitude is medium for the channel, the transmitter's power amplifier adjusts the power of the transmitted signal according to the signal fading amplitude. When the signal fading amplitude is between 3dB and 6dB, the power amplifier is used to reduce the transmit power. When the signal fading amplitude is between 6dB and 10dB, the power amplifier is used to increase the transmit power. When the signal fading amplitude is high for the channel, diversity reception technology is used in the receiver, using antennas with different polarization modes to receive signals. The signals received by antennas with different polarization modes are independent, and the signals received by antennas with different polarization modes are combined and processed. When the signal fading duration is low for the channel, the multipath fading of the channel is less affected by the signal fading duration, and the signal fading duration is continuously monitored. When the signal fading duration is medium for the channel, the encoder in the scheduling transmitter uses interleaving technology to interleave continuous signals, spreading the continuous signals in time, and uses information from the non-faded signal to correct the fading signal. When the signal fading duration is high for the channel, the decoder in the scheduling receiver uses a soft decision algorithm to extract the reliability information of the received signal and encode the reliability information. When the channel bandwidth has a low impact on the channel capacity, the channel capacity is less affected by the channel bandwidth and the channel bandwidth is continuously monitored. When the channel bandwidth has a medium impact on the channel capacity, the modulator in the transmitter adjusts the modulation mode according to the slope of the channel bandwidth-channel capacity curve. When the slope of the channel bandwidth-channel capacity curve is between 0.1 and 1, high-order modulation is used. When the slope of the channel bandwidth-channel capacity curve is between 1 and 3.5, low-order modulation is used. When the channel bandwidth has a high impact on the channel capacity, the equalizer in the receiver adjusts the number of its taps according to the channel bandwidth. When the slope of the channel bandwidth-channel capacity curve is between 0.1 and 1, the number of taps is increased. When the slope of the channel bandwidth-channel capacity curve is between 1 and 3.5, the number of taps is reduced. The demodulator is also scheduled to adjust the sampling frequency to match the sampling frequency with the channel bandwidth.

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