WO2013185698A1 - Crest factor reduction apparatus and method for msr system transmitter - Google Patents

Abstract

A crest factor reduction apparatus and method for an MSR system transmitter. The apparatus comprises a carrier signal amplitude obtaining module used for obtaining the amplitude of each sampling point signal of a carrier data signal from an MSR signal, a crest factor reduction threshold obtaining module connected with the carrier signal amplitude obtaining module and used for obtaining a crest factor reduction threshold needed by the current MSR system transmitter, and a crest factor reduction processing module connected with the carrier signal amplitude obtaining module and the crest factor reduction threshold obtaining module separately and used for carrying out crest factor reduction processing on the MSR signal according to a signal amplitude input by the carrier signal amplitude obtaining module and a crest factor reduction threshold input by the crest factor reduction threshold obtaining module. By means of embodiments of the present invention, the crest factor reduction threshold can be adjusted adaptively according to multi-standard radio carrier RF bandwidths and the number of each type of standard radio carriers to achieve an optimal peak-to-average ratio of the MSR signal sent out from radio frequency power amplification of a base station, so that the device linearity and efficiency are balanced, and the signal emission quality is improved at the same time.

Description

 MSR system transmitter peak clipping device and method

 The present invention relates to the field of wireless communications, and in particular to a CSR (Cover Factor Reduction, CFR) device and method for a MSR (Multi-Standard Radio) system.

Background technique

 The communication system generally uses two-phase phase shift keying BPSK, quadrature phase shift keying QPSK, eight phase shift keying 8PSK, 16QAM (six-symbol quadrature amplitude modulation) modulation schemes with high spectrum utilization. These modulation methods not only modulate the phase of the carrier, but also modulate the amplitude of the carrier. Therefore, these modulation methods produce a non-constant envelope modulation signal having a large peak-to-average ratio. The most serious one is the RF power amplifier. At present, it can only be solved by the peak clipping algorithm. If the signal clipping is too large, the signal loss is serious, which affects the device efficiency and communication signal quality. If the signal clipping peak is too small, the active device is made. Working in the nonlinear region, the out-of-band intermodulation component is generated, and the adjacent channel leakage ratio is poor, causing interference to other systems.

 With the development of wireless networks, Multi-Standard Radio (MSR) convergence has become a trend. Multi-carrier signals in multi-standard systems will inevitably lead to higher peak-to-average ratios. Currently, fixed peak clipping is generally used. The peak clipping strategy of the threshold, and as the radio frequency (RF) bandwidth of the multi-carrier signal becomes wider and wider, the peak clipping rate and peak processing resources are limited, the peak clipping strategy of the fixed clipping threshold is obviously not good. Solve the contradiction between RF amplifier linearity and signal quality.

Summary of the invention

 The object of the embodiments of the present invention is to provide a device and method for peak clipping of a transmitter of an MSR system, which can determine the contradiction between linearity and signal quality of the RF power amplifier by adaptively determining the peak clipping threshold.

 An MSR system transmitter peak clipping apparatus according to an embodiment of the present invention includes: a carrier signal amplitude acquisition module configured to acquire a magnitude of each sample point signal of a carrier data signal from a multi-standard MSR signal;

Connecting a peak clipping threshold acquiring module of the carrier signal amplitude acquiring module, configured to acquire a current Peak clipping threshold required for MSR system transmitters;

 And respectively connecting the carrier signal amplitude obtaining module and the peak clipping processing module of the peak clipping threshold acquiring module, and setting the peak value of the signal input by the module according to the carrier signal amplitude acquiring module and the clipping peak input by the clipping peak threshold acquiring module Threshold, peak clipping processing of the MSR signal.

 Preferably, the peak clipping threshold acquisition module includes: a bandwidth and carrier number acquisition submodule, configured to acquire, from the MSR system, a radio frequency bandwidth of a current carrier signal and a number of carriers in each standard; And a peak clipping threshold determining submodule between the carrier number obtaining submodule and the carrier signal amplitude acquiring module, configured to acquire the radio frequency bandwidth and the number of carriers and the carrier signal amplitude sent by the submodule according to the bandwidth and the number of carriers The value is obtained by the module, and the table is used to obtain the peak clipping threshold.

 Preferably, the peak clipping processing module includes: an initial peak clipping coefficient calculation submodule respectively connected to the carrier signal amplitude acquisition module and the peak clipping threshold determination submodule, and configured to input a signal amplitude input by the carrier signal amplitude acquisition module The value is compared with the peak clipping threshold of the peak clipping threshold determination sub-module, and the initial peak clipping coefficient is calculated; the offset peak clipping coefficient generation sub-module of the initial peak clipping coefficient calculation sub-module is connected, and the initial peak clipping coefficient is set. Calculating the initial peak clipping coefficient sent by the sub-module to perform peak search and filtering processing to obtain the canceling pulse peak clipping coefficient; connecting the cancellation pulse peak clipping coefficient generating sub-module cancellation pulse generating sub-module, and setting the peak clipping coefficient according to the cancellation pulse Generating a cancellation pulse peak clipping coefficient sent by the sub-module to generate a cancellation pulse; connecting a peak clipping sub-module of the cancellation pulse generation sub-module, configured to cancel the cancellation pulse sent by the cancellation pulse generation sub-module and the MSR signal, The MSR signal after peak clipping is obtained.

 Preferably, the carrier signal amplitude acquisition module includes: a sample point signal acquisition submodule for acquiring each sample point signal of the carrier data signal; and a signal amplitude calculation submodule for connecting the sample point signal acquisition submodule, setting To calculate the signal amplitude of each sample point signal.

 Preferably, the initial peak clipping coefficient calculation submodule is a peak detection unit connected to the signal amplitude calculation submodule.

 Preferably, the canceling pulse peak clipping coefficient sub-module comprises: a peak search unit connected to the peak detecting unit; and a peak filtering unit connected to the peak search unit.

The MSR system transmitter peak clipping apparatus of the embodiment of the present invention further includes a signal amplitude connected to the signal The phase angle delay sub-module between the calculation sub-module and the cancellation pulse generation sub-module.

 Preferably, the peak clipping sub-module is a subtractor.

 A method for peak clipping of a transmitter of an MSR system according to an embodiment of the present invention includes: acquiring amplitudes of signal points of carrier data signals from a multi-standard MSR signal; and obtaining peak clipping required by a current MSR system transmitter Threshold

 The MSR signal is subjected to peak clipping processing according to the amplitude of each sample point signal and the peak clipping threshold.

 Preferably, the obtaining a peak clipping threshold required by the current MSR system transmitter includes: obtaining, from the MSR system, an RF bandwidth of a current carrier signal and a number of carriers in each system;

 The peak clipping threshold is obtained by looking up the table according to the radio frequency bandwidth and the number of carriers and the amplitude of each of the sample points.

 Preferably, the peak clipping processing of the MSR signal according to the amplitude of each sample point signal and the peak clipping threshold comprises:

 Comparing the amplitudes of the respective sample points with the peak clipping threshold to calculate an initial peak clipping coefficient;

 Performing a peak search and filtering process on the initial peak clipping coefficient to obtain a cancellation pulse peak clipping coefficient; generating a cancellation pulse according to the cancellation pulse peak clipping coefficient;

 The cancellation pulse is cancelled with the MSR signal to obtain a peaked MSR signal.

 Preferably, the obtaining the amplitude of each sample point signal of the carrier data signal from the multi-standard MSR signal comprises:

 Acquire each sample signal of the carrier data signal, and calculate the signal amplitude of each sample signal.

Compared with the related art, the technical effect of the embodiment of the present invention is that the peak clipping threshold can be adaptively adjusted according to the multi-standard carrier RF bandwidth and the number of carriers per system, so as to achieve the peak-to-average ratio of the MSR signal from the base station RF power amplifier. To balance the linearity and efficiency of the device while improving the quality of the transmitted signal. BRIEF abstract

 1 is a schematic diagram of a transmitter peak clipping device of an MSR system according to an embodiment of the invention;

 2 is a schematic diagram of the peak clipping threshold acquisition module of FIG. 1;

 Figure 3 is a schematic diagram of the peak clipping processing module of Figure 1;

 4 is a circuit diagram of a transmitter peak clipping device of an MSR system according to an embodiment of the present invention;

 5 is a flow chart of a method for peak clipping of a transmitter of an MSR system according to an embodiment of the present invention;

 Figure 6 is a schematic diagram illustrating the operation of an embodiment of the present invention. Preferred embodiment of the invention

 1 shows the basic structure of a transmitter peak clipping device for an MSR system according to an embodiment of the present invention. As shown in FIG. 1, the peak clipping device includes:

 The carrier signal amplitude acquiring module 1 is configured to obtain the amplitude of each sample signal of the carrier data signal from the MSR signal;

 The peak clipping threshold acquisition module 2 of the carrier signal amplitude acquisition module 1 is set to acquire the current

Peak clipping threshold required for MSR system transmitters;

 The peak clipping processing module 3 of the carrier signal amplitude obtaining module 1 and the peak clipping threshold obtaining module 2 are respectively connected, and are set to be converted according to the signal amplitude input by the carrier signal amplitude acquiring module 1 and the clipping peak input obtaining module 2 Peak threshold, peak clipping processing of the MSR signal.

 FIG. 2 shows the specific structure of the peak clipping threshold acquisition module 2 in FIG. 1, and the peak clipping threshold acquisition module 2 includes:

 The bandwidth and carrier number acquisition sub-module 21 is configured to obtain the radio frequency bandwidth of the current carrier signal and the number of carriers in each standard from the MSR system;

The peak clipping threshold determining sub-module 22 connected between the bandwidth and carrier number obtaining sub-module 21 and the carrier signal amplitude acquiring module 1 is configured to acquire the radio frequency bandwidth sent by the sub-module 21 according to the bandwidth and the number of carriers. The number of carriers and the amplitude of the carrier signal amplitude acquisition module 1 are obtained, and the peak clipping threshold is obtained by looking up the table. FIG. 3 shows a specific structure of the peak clipping processing module 3 of FIG. 1. As shown in FIG. 3, the peak clipping processing module 3 includes:

 The initial peak clipping coefficient calculation sub-module 31 of the carrier signal amplitude obtaining module 1 and the peak clipping threshold determining sub-module 21 is respectively connected, and is set to the signal amplitude and peak clipping threshold determining sub-module 21 input by the carrier signal amplitude acquiring module 1 . The input peak clipping threshold is compared to calculate an initial peak clipping coefficient; the offset peak clipping coefficient generation sub-module 32 of the initial peak clipping coefficient calculation sub-module 31 is connected to the initial peak clipping coefficient calculation sub-module 31. The initial peak clipping coefficient is subjected to peak search and filtering processing to obtain a canceling pulse peak clipping coefficient;

 The canceling pulse generating sub-module 33 of the connection canceling pulse peak clipping coefficient generating sub-module 32 is arranged to generate a canceling pulse according to the canceling pulse clipping coefficient fed by the canceling pulse peak clipping coefficient generating sub-module 32;

 The peak clipping sub-module 34 of the connection cancellation pulse generation sub-module 33 is arranged to cancel the cancellation pulse sent by the cancellation pulse generation sub-module 33 and the MSR signal to obtain a peaked MSR signal.

 FIG. 4 shows a specific embodiment of the MSR system transmitter peak clipping apparatus according to the embodiment of the present invention. As shown in FIG. 4, the carrier signal amplitude acquisition module 1 of the embodiment of the present invention may include: acquiring carrier data signals. The sample point signal acquisition sub-module 11 of the point signal can be composed of a field programmable gate array FPGA; the signal amplitude calculation sub-module 12 of the sample node acquisition sub-module FPGA is set to calculate the signal of each sample point Signal amplitude.

 As shown in FIG. 4, the initial peak clipping coefficient calculation sub-module 31 in FIG. 3 may be a peak detection unit connected to the signal amplitude calculation sub-module. Further, as shown in FIG. 4, the canceling pulse peak clipping coefficient sub-module 32 in FIG. 3 may include: a peak search unit 321 connected to the peak detecting unit; and a peak value filtering unit 322 connected to the peak search unit.

 In addition, as shown in FIG. 4, the embodiment of the present invention may further include a phase angle delay sub-module 4 connected between the signal amplitude calculation sub-module 12 and the cancellation pulse generation sub-module 33.

 Further, as shown in FIG. 4, the peak clipping sub-module in FIG. 3 is a subtractor.

As shown in FIG. 5, the inventor embodiment further provides a method for peak clipping of a transmitter of an MSR system. Includes the following steps:

 SI: Obtain the amplitude of each sample signal of the carrier data signal from the multi-standard MSR signal; S2: Obtain the peak clipping threshold required by the current MSR system transmitter;

 S3: Perform peak clipping processing on the MSR signal according to the amplitude of each sample point signal and the peak clipping threshold.

 The foregoing method of the embodiment of the present invention specifically includes:

 1. Determine whether the carrier data signal exists in the MSR system, and if so, obtain the amplitude of each sample point of the carrier signal;

 2. The MSR system obtains the RF bandwidth of the current carrier signal and the number of carriers in each system; 3. The integrated power value (ie, amplitude), the RF bandwidth, and the number of standard carriers are obtained to obtain the transmitter under the current MSR working system. The peak clipping threshold required by the peak clipping algorithm;

 4. The amplitude of each sample signal is compared with the peak clipping limit, and the initial peak clipping coefficient is calculated;

5. Generate a canceling pulse peaking coefficient suitable for peak clipping by using a peak search module and a filter processing module;

 6. The ablation pulse is generated according to the peak clipping coefficient, and the pulse is cancelled by the original signal to complete the peak clipping. The embodiment of the invention solves the problem that the RF bandwidth and the number of standard carriers in the MSR system are inconsistent, and the peak-to-average ratio of the signal from the transmitter DAC is large when the peak clipping rate is constant, which makes the linearity, efficiency and signal quality of the RF power amplifier difficult. The problem of balancing, the specific working principle is shown in Figure 6, including:

 Step 1: First, determine whether there is a carrier data signal in the MSR system, and if so, calculate the amplitude and phase of each sample signal;

 Step 2: The MSR system obtains the number of carriers in each standard of the current MSR system; Step 3: The MSR system calculates an interval of the RF bandwidth of the current MSR signal;

Step 4: Determine whether the RF bandwidth and the number of carriers of the current multi-carrier signal change with respect to the previous time by using the specified flag signal. If the change occurs, perform step 5, otherwise perform step 6; Step 5: Update the carrier in the MSR system. The interval to which the signal RF bandwidth belongs and the number of carriers in each system; Step 6: According to the calculated amplitude, RF bandwidth information and the number of carrier numbers of the sample points, the peak clipping threshold of the peak clipping operation is obtained. If the signal amplitude is greater than the peak clipping threshold, the signal amplitude and The peak clipping threshold is directly subtracted, and the weighted initial peak clipping coefficient is calculated, and the signal smaller than the clipping peak threshold is directly zeroed;

 Step 7: Determine the peak position by means of a peak search module, and process the initial peak coefficient by the coefficient filter module according to the current carrier frequency of the link, etc., to generate a peak clipping coefficient suitable for the current peak clipping process;

 Step 8: According to the peak clipping coefficient of the structure, the cancellation pulse is constructed compared with the original signal, and the peak clipping process is completed by subtracting the signal pulse from the canceling pulse;

 In addition, by looking at the peak clipping threshold, different peak clipping thresholds are used for different RF bandwidths and standard carrier numbers in the MSR system. The table peak clipping threshold is calculated as follows:

 1. If the carrier signal is detected as a single mode / single mode signal:

 a. If it is a single carrier data signal, the peak clipping threshold CFR_limit= Limit(SR_SC);

 b. If it is a multi-carrier data signal, the peak clipping threshold CFR_limit= Limit(SR_SC)+K (RF BW);

 Among them, Limit (SR - SC) represents the peak clipping threshold of a single-mode single-carrier operating system. RF-BW is the RF bandwidth in a single-mode multi-carrier system. The compensation coefficient Limit(SR-SC) > K > 0, K is related to the RF bandwidth. K is 0 for single carrier, and K is associated with RF for a given single-mode multi-carrier system. The bandwidth increase increases nonlinearly. The variation of K with RF bandwidth in different standards can be inconsistent, mainly depending on the peak-to-average ratio of signals of different standards.

 2. If the detected carrier signal is a multi-mode/multi-mode signal, for example, GSM&E UTRA&UTRA mixed-mode signal:

 MSR_CFR_limit= Limit(S_Radio)+K (RF BW );

 Among them, Limit(S-Radio)=MAX[G single carrier signal lower clipping threshold, E-UTRA single carrier signal lower clipping threshold, UTRA single carrier signal lower clipping threshold], compensation coefficient Limit(S-Radio) > K > 0, the single carrier signal is 0 0, 非线性 increases nonlinearly with increasing RF bandwidth, and K is related to RF bandwidth and the number of carriers per MSC system.

The embodiment of the invention can be adapted according to the multi-standard carrier R bandwidth and the number of carriers per system. The peak clipping threshold is adjusted to achieve the best peak-to-average ratio of the MSR signal from the base station RF power amplifier, so that the linearity and efficiency of the device are balanced, and the quality of the transmitted signal is improved.

 Although the invention has been described in detail above, the invention is not limited thereto, and various modifications may be made by those skilled in the art in accordance with the principles of the invention. Therefore, modifications in accordance with the principles of the invention should be understood as falling within the scope of the invention.

Industrial applicability

 In the embodiment of the present invention, the peak clipping threshold can be adaptively adjusted according to the multi-standard carrier R bandwidth and the number of carriers per system, so that the peak-to-average ratio of the MSR signal from the base station RF power amplifier is optimal, and the linearity and efficiency of the device are balanced. Improve the quality of the transmitted signal.

Claims

Claim

 1. A MSR system transmitter peak clipping device, comprising:

 The carrier signal amplitude acquiring module is configured to acquire the amplitude of each sample signal signal of the carrier data signal from the multi-standard MSR signal;

 Connecting a peak clipping threshold acquiring module of the carrier signal amplitude acquiring module, configured to acquire a current

Peak clipping threshold required for MSR system transmitters;

 And respectively connecting the carrier signal amplitude obtaining module and the peak clipping processing module of the peak clipping threshold acquiring module, and setting the peak value of the signal input by the module according to the carrier signal amplitude acquiring module and the clipping peak input by the clipping peak threshold acquiring module Threshold, peak clipping processing of the MSR signal.

 2. The apparatus according to claim 1, wherein the peak clipping threshold acquisition module comprises: a bandwidth and carrier number acquisition submodule, configured to acquire a radio frequency bandwidth of a current carrier signal from the MSR system and each system Number of carriers;

 And a peak clipping threshold determining sub-module connected between the bandwidth and carrier number obtaining sub-module and the carrier signal amplitude acquiring module, configured to acquire a radio frequency bandwidth and a carrier group sent by the sub-module according to the bandwidth and the number of carriers The number and the amplitude of the carrier signal amplitude acquisition module are sent to the table to obtain the peak clipping threshold.

 The apparatus according to claim 1 or 2, wherein the peak clipping processing module comprises: an initial peak clipping coefficient calculation submodule respectively connected to the carrier signal amplitude acquisition module and the peak clipping threshold determination submodule, In order to compare the amplitude of the signal input by the carrier signal amplitude acquisition module with the clipping peak threshold of the peak clipping threshold determination sub-module, the initial peak clipping coefficient is calculated;

 Connect the offset peak clipping coefficient generation sub-module of the initial peak clipping coefficient calculation sub-module, and set the initial peak clipping coefficient sent to the initial peak clipping coefficient calculation sub-module to obtain the offset pulse peak clipping coefficient after peak search and filtering processing. .

4. The apparatus according to claim 3, wherein the peak clipping processing module further comprises: a cancellation pulse generation sub-module connected to the cancellation pulse peak clipping coefficient generation sub-module, configured to generate a sub-peak according to the cancellation pulse clipping coefficient The offset pulse clipping coefficient sent by the module generates an offset pulse; the peak clipping sub-module connected to the cancellation pulse generation sub-module is set to cancel the pulse generation sub-module The cancellation pulse sent by the module is cancelled by the MSR signal to obtain the MSR signal after the peak clipping.

 5. The apparatus according to claim 2, wherein the carrier signal amplitude acquisition module comprises:

 The sample point signal acquisition sub-module is configured to acquire each sample point signal of the carrier data signal; and connect the signal amplitude calculation sub-module of the sample point acquisition sub-module, and set to calculate the signal amplitude of each sample point signal .

 6. The apparatus according to claim 5, wherein the initial peak clipping coefficient calculation sub-module is a peak detection unit connected to the signal amplitude calculation sub-module.

 7. The apparatus according to claim 3, wherein the canceling pulse peak clipping coefficient sub-module comprises:

 Connecting a peak search unit of the peak detecting unit;

 A peak filtering unit that connects the peak search unit.

 8. The apparatus of claim 5, further comprising a phase angle delay sub-module coupled between the signal amplitude calculation sub-module and the cancellation pulse generation sub-module.

 9. The apparatus according to claim 4, wherein the peak clipping sub-module is a subtractor.

10. A method for peak clipping of a transmitter of an MSR system, comprising:

 Obtaining the amplitude of each sample signal of the carrier data signal from the multi-standard MSR signal; obtaining the peak clipping threshold required by the current MSR system transmitter;

 The MSR signal is subjected to peak clipping processing according to the amplitude of each sample point signal and the peak clipping threshold.

 The method according to claim 10, wherein the obtaining a peak clipping threshold required by the current MSR system transmitter comprises: acquiring, from the MSR system, a radio frequency bandwidth of a current carrier signal and a carrier number of each standard system. Number

The peak clipping threshold is obtained by looking up the table according to the RF bandwidth and the number of carriers and the amplitude of each of the sample points.

The method according to claim 10 or 11, wherein the peak clipping processing of the MSR signal according to the amplitude of each sample point signal and the peak clipping threshold comprises:

 Comparing the amplitudes of the respective sample points with the peak clipping threshold to calculate an initial peak clipping coefficient;

 Performing a peak search and filtering process on the initial peak clipping coefficient to obtain a cancellation pulse peak clipping coefficient; generating a cancellation pulse according to the cancellation pulse peak clipping coefficient;

 The cancellation pulse is cancelled with the MSR signal to obtain a peaked MSR signal.

 13. The method according to claim 11, wherein the obtaining the amplitude of each sample point signal of the carrier data signal from the multi-standard MSR signal comprises:

 Acquire each sample signal of the carrier data signal, and calculate the signal amplitude of each sample signal.