WO2012174972A1 - Power amplifier protection method and device - Google Patents

Abstract

A power amplifier protection method, including: respectively performing delay processing and power detection processing on a digital signal to be transmitted, the duration of the delay processing being equal to that of the power detection processing; and, after it is detected that an exception has occurred in the digital signal to be transmitted, performing shutdown processing on the portion in the delayed digital signal to be transmitted in which an exception has occurred. Also disclosed is a corresponding device, including a transmission signal delay unit, a power detection processing unit and a power amplifier protection execution unit. The present application ensures that a power amplifier protection measure is performed on a digital medium-frequency link before the delayed transmission signal has been outputted to the power amplifier if temporary high power, continuous high power or a wideband signal occur which may compromise the power amplifier, thus effectively protecting the power amplifier.

Description

 Method and device for protecting power amplifier

Technical field

 The present invention relates to the field of mobile communications, and in particular, to a method and apparatus for protecting a power amplifier.

Background technique

 In the field of mobile communication, the base station system is composed of a baseband unit (BBU) and a radio remote unit (RRU). The RRU transmission link mainly receives the baseband signal from the BBU, and performs digital domain processing, DAC (Digital to Analog Converter) conversion, signal up-conversion, RF power amplification, signal filtering, etc. on the baseband signal, and finally radiates to the free space through the antenna. . The power and quality of the RRU output signal directly determine the coverage and cell service of the cell. The RF power amplifier acts as the end unit of the entire base station system. The stability and reliability of the operation directly affect the normal operation of the base station system. The coverage of the cell and the normal operation of the service. At the same time, since the power amplifier is a high-power RF device, it is the most vulnerable device in the working process of the base station system. Therefore, it is an important content to take corresponding protection measures for the power amplifier in the product design process.

 Under normal circumstances, the reason for the power amplifier damage is that some high-power abnormal signals are introduced in the link processing. After these high-power signals enter the power amplifier, there is a possibility of impact on the power amplifier. These abnormal signals mainly include:

 1) long time high power signal;

 2) instantaneous super power signal;

 3) broadband signals;

 4) Larger glitch (ie, instantaneous broadband signal).

At present, the commonly used power amplifier protection technology is realized by a combination of hardware detection circuit and software control. The implementation of this method is to detect the output power of the transmitted signal, the PA (Power Amplifier) temperature, the VSWR (Voltage Standing Wave Ratio), etc. through the hardware detection circuit, and detect that the power amplifier may be damaged. When an abnormal situation occurs, However, the above power amplifier protection methods have the following disadvantages:

 1) can not effectively solve the damage caused by the glitch or wideband input signal;

 2) The abnormal signal that may cause damage to the power amplifier cannot be judged in advance to protect in advance;

3) The instantaneous high-power input signal is one of the main reasons for the power amplifier damage. The current power amplifier protection method cannot protect the instantaneous high-power signal, because the hardware detects the instantaneous high-power signal and then passes the software processing to the execution. In the process of power amplifier protection, the instantaneous high-power signal has been input to the power amplifier, and when the protection measures are taken, the instantaneous high-power signal may have disappeared, so the power amplifier does not have a real protection effect.

 The invention with the application number CN200610032779.0 discloses a base station power amplifier protection method and device, which reduces the transmission power by congestion control, and triggers the reduction of the data channel by the congestion control when the instantaneous high power signal occurs. The power amplifier protection mode of the transmit power. Since this protection method is implemented by high-level software control, the response speed is slow. When the abnormal signal is triggered to the power amplifier protection execution, the instantaneous high-power input of the power amplifier has returned to normal, so this method can not effectively respond to the instantaneous high-power abnormal signal. In order to protect, the power signal protection strategy that reduces the data channel and reduces the signal transmission power is affected when the high-power signal has disappeared and the input signal returns to normal. Therefore, this power amplifier protection method can not only effectively protect the power amplifier from the instantaneous high-power abnormal signal, but will affect the normal operation of the system business. Summary of the invention

 The object of the present invention is to provide a method and a device for protecting a power amplifier. The power amplifier protection method has been solved not only cannot effectively protect the power amplifier, but also affects the normal defects of the system service.

 To solve the above problems, the present invention provides a method for protecting a power amplifier, including:

 The digital signals to be transmitted are respectively subjected to delay processing and power detection processing; wherein, the duration of the delay processing is equal to the duration of the power detection processing;

 After detecting that the digital signal to be transmitted is abnormal, the part of the digital signal to be transmitted after the delay is turned off.

Preferably, the performing power detection processing on the digital signal to be transmitted includes: Performing single point power detection on the digital signal to be transmitted;

 The detecting that the digital signal to be transmitted is abnormal, includes:

 The power value of the at least one signal point of the digital signal to be transmitted is greater than a preset single point power threshold;

 And performing the shutdown processing on the abnormal part of the digital signal to be transmitted after the delay, including:

 The delayed digital signal to be transmitted is transmitted according to a fixed power value, or the signal point data whose power value is greater than a preset single-point power threshold is discarded.

 Preferably, the performing power detection processing on the digital signal to be transmitted includes: performing average power detection on the digital signal to be transmitted;

 The detecting that the digital signal to be transmitted is abnormal, includes:

 The average power value of the signal point in the digital signal to be transmitted is greater than a preset average power threshold;

 And performing the shutdown process on the abnormal portion of the digital signal to be transmitted after the delay, including: reducing the power of the delayed digital signal to be transmitted to zero after the delay.

 Preferably, the performing power detection processing on the digital signal to be transmitted includes: performing broadband signal detection on the digital signal to be transmitted;

 The detecting that the digital signal to be transmitted is abnormal, includes:

 The in-band noise floor power value other than the useful signal is greater than a preset wideband signal power threshold value; and the shutting down the abnormal portion in the digital signal to be transmitted after the delay, including: The power of the digital signal to be transmitted after the time is gradually reduced to zero and then transmitted.

 Preferably, the method further includes: after detecting that the digital signal to be transmitted returns to normal, increasing the power of the delayed digital signal to be transmitted to the original transmit power step by step.

 Accordingly, the present invention also provides an apparatus for protecting a power amplifier, including:

a transmitting signal delay unit, configured to: delay processing the digital signal to be transmitted; wherein, the duration of the delay processing is equal to the duration of the power detection processing performed by the power detection processing unit; a power detection processing unit, configured to: perform power detection processing on the digital signal to be transmitted;

 The power amplifier protection execution unit is configured to: after the power detection processing unit detects that the digital signal to be transmitted is abnormal, perform a shutdown process on the abnormal portion of the digital signal to be transmitted after the delay.

 Preferably, the power detection processing unit includes a single-point power detecting unit, configured to: perform single-point power detection on the digital signal to be transmitted; and detect at least one signal point in the digital signal to be transmitted. When the power value is greater than a preset single-point power threshold, determining that the digital signal to be transmitted is abnormal;

 The power amplifier protection execution unit is configured to: perform a shutdown process on a portion of the digital signal to be transmitted after the delay, including: transmitting the delayed digital signal after the delay according to a fixed power value, or Signal point data with a power value greater than the preset single-point power threshold is discarded. Performing average power detection on the digital signal to be transmitted; determining that the digital signal to be transmitted occurs when detecting that the average power value of the signal point in the digital signal to be transmitted is greater than a preset average power threshold Abnormal

 The power amplifier protection execution unit is configured to: perform a shutdown process on the abnormal portion of the digital signal to be transmitted after the delay, including: reducing the power of the delayed digital signal to be transmitted to zero After the launch.

 Preferably, the power detection processing unit further includes a wideband signal detecting unit, configured to: perform broadband signal detection on the digital signal to be transmitted; and detect an out-band noise floor power value other than the useful signal. When the broadband signal power threshold is set, it is determined that the digital signal to be transmitted is abnormal;

 The power amplifier protection execution unit is configured to: perform a shutdown process on the abnormal portion of the digital signal to be transmitted after the delay, including: reducing the power of the delayed digital signal to be transmitted to zero After the launch.

Preferably, the power amplifier protection execution unit is further configured to: after the power detection processing unit detects that the digital signal to be transmitted returns to normal, the delayed digital signal to be transmitted The power is increased step by step to the original transmit power and then transmitted.

After the embodiment of the present invention is used, it can be ensured that when a transient high-power, continuous high-power, wide-band signal that may cause power amplifier damage occurs, the delayed transmission signal is not output to the PA, but on the digital intermediate frequency link. Perform power amplifier protection measures to effectively protect the amplifier. And the amplifier protection is implemented internally by an FPGA (Field - Programmable Gate Array), and the response of the amplifier protection and recovery is fast. In addition, this method of controlling the digital IF signal to turn off the power amplifier protection can achieve smooth turn-off and turn-on of the transmitted signal, avoiding the power amplifier damage caused by the sudden opening and closing of the high-power signal.

BRIEF abstract

 1 is a schematic view showing the position of a power amplifier protection device in an embodiment of the present invention;

 2 is a block diagram showing the composition of a power amplifier protection device in an embodiment of the present invention. Preferred embodiment of the invention

 In order to make the objects, the technical solutions and the advantages of the present invention more clearly, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, in the case of no conflict, the features in the embodiments and the embodiments of the present application may be arbitrarily combined with each other.

 In this embodiment, a method for protecting a power amplifier is applied to an RRU, including:

 Step 10: performing delay processing and power detection processing on the digital signals to be transmitted respectively; wherein, in the process of performing delay processing, the duration of the delay needs to be equal to the length of time required for performing the power detection processing;

Performing power detection may include: performing single point power detection, average power detection, and wideband signal detection on the digital signals to be transmitted. The single-point power detection means: detecting the power of each of the signal points to be transmitted, respectively, and determining whether the power of the current signal point is greater than a preset single-point power threshold; the average power detection is: Detecting an average power of the signal points in the digital signal to be transmitted, determining whether the average power is greater than a preset average power threshold; and detecting the broadband signal by: detecting the in-band noise floor power other than the useful signal , judge the inside of the band Whether the noise floor power is greater than a preset wideband signal power threshold.

 If any of the foregoing detection results is greater than the corresponding preset threshold, it is determined that the digital signal to be transmitted is abnormal;

 Step 20: After detecting that the digital signal to be transmitted is abnormal, the part of the data signal to be transmitted after the delay is abnormally turned off.

 In this step, a reasonable shutdown processing strategy needs to be designed for the abnormal signal to be transmitted, and different signal shutdown strategies can be correspondingly selected for the digital signals to be transmitted exceeding the preset thresholds. For a digital signal to be transmitted that exceeds the single-point power threshold, a strategy of transmitting at a fixed power value or directly discarding the transmitted signal zero data is performed; for an abnormality exceeding the average power threshold The transmitted digital signal or wideband signal uses a strategy of gradually reducing the power of the digital signal to be transmitted to zero to perform power amplifier protection. After detecting the abnormal signal cancellation, the digital signal to be transmitted returns to normal, and then recovers from zero to the original transmission power, thereby effectively avoiding the sudden turn-off of the input signal and opening the impact on the power amplifier, that is, waiting at the digital intermediate frequency. When the transmitted digital signal is turned off, a sequence of functions from 1 to 0 is generated and multiplied by the power of the delayed digital signal to be transmitted, and then transmitted, so that the transmitted signal is smoothly turned off; after the abnormal signal disappears, A sequence of functions from 0 to 1 is generated and multiplied by the delayed digital signal to be transmitted, so that the digital signal to be transmitted is smoothly turned on.

 The position of the power amplifier protection device provided by the present invention implemented in the system is as shown in Fig. 1, that is, the attack and defense protection is performed before the digital-to-analog conversion of the signal.

 As shown in FIG. 2, in the present example, the power amplifier protection device includes: a single-point power detecting unit 203, an average power detecting unit 204, a wideband signal detecting unit 205, a transmitting signal delay unit 201, and a power amplifier protection executing unit 202; The single point power detecting unit 203, the average power detecting unit 204, and the wideband signal detecting unit 205 constitute a power detecting processing unit.

The single-point power detecting unit 203, the average power detecting unit 204, and the wideband signal detecting unit 205 respectively perform single-point power detection, average power detection, and wide-band signal detection on the digital signal to be transmitted, and the detected single-point power value, The average power value, the in-band noise floor power value is compared with the set corresponding threshold value, and when any one of the single point power, the average power or the wideband signal power value exceeds the corresponding threshold value, the to-be-transmitted is determined. The digital signal is abnormal; The transmitting signal delay unit is configured to perform delayed transmission processing on the digital signal to be transmitted; the unit performs delayed transmission on the signal to be transmitted, and the largest time required for single point power detection, average power detection, and wideband signal detection is Transmit signal delay value;

 The power amplifier protection execution unit 205 is configured to: when the single-point power detecting unit 203, the average power detecting unit 204, and the wideband signal detecting unit 205 determine that the data signal to be transmitted is abnormal, select a power amplifier protection strategy and perform power amplifier protection. When the unit knows that the data signal to be transmitted is abnormal, the corresponding protection strategy is selected according to the abnormal situation (ie: for single point over power, the data is discarded or reduced to a suitable power value for transmission; for the average power Power anomalies and wideband signal anomalies, using a sequence function from 1 to 0 multiplied by the delayed digital signal to be transmitted, the signal is smoothly turned off). When the signal link is normal, to recover the transmitted signal, a sequence function from 0 to 1 is multiplied by the transmitted signal, and the transmitted signal is smoothly turned on to restore the forward transmitted signal. The power amplifier protection execution unit achieves a smooth turn-off and turn-on of the transmitted signal by multiplying a sequence of functions from 1 to 0 or from 0 to 1 and the delayed digital signal to be transmitted. When the transmit signal is turned off and on, the function sequence function used can select a suitable sequence according to the current system rated power, carrier number, carrier bandwidth and other parameters. A commonly used linear step sequence, such as when the transmit signal is turned off, the transmit signal is turned off to 0 in five consecutive transmit data, and the sequence (0.8, 0.6, 0.4, 0.2, 0) can be used, and the sequence is used when turned on. ( 0.2, 0.4, 0.6, 0.8, 1 ) , you can also choose a nonlinear sequence, such as a sequence of functions of (1-N ) / ( 1+N ), where N is 0.2, 0.4 when the signal is turned off. 0.6, 0.8, 1 , The open signal is N, which is 0.8, 0.6, 0.4, 0.2, 0.

 Further explanation will be made below with an application example of the present invention.

 Ways to protect the amplifier, including:

 (1) The digital signals to be transmitted are respectively subjected to delay processing, single-point power detection, average power detection, and wide-band signal detection; wherein, the duration of the delay is equal to the length of time required for the above three detection processes;

 (2) If it is detected that the power of at least one of the digital signals to be transmitted exceeds the single-point power threshold, then the data point is transmitted at a fixed power value or the signal point data is directly discarded to transmit a zero signal. Strategy

(3) If it is detected that the average power of the transmitted digital signal exceeds the average power threshold or If there is an abnormal wideband signal in the digital signal, the power of the digital signal to be transmitted is gradually reduced to zero for power amplifier protection.

One of ordinary skill in the art will appreciate that all or a portion of the above steps may be accomplished by a program instructing the associated hardware, such as a read-only memory, a magnetic disk, or an optical disk. Alternatively, all or part of the steps of the above embodiments may also be implemented using one or more integrated circuits. Correspondingly, each module/unit in the above embodiment may be implemented in the form of hardware or in the form of a software function module. The invention is not limited to any specific form of combination of hardware and software.

 The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. In view of the present invention, various other modifications, equivalents, improvements, etc., should be made without departing from the spirit and scope of the invention. It is included in the scope of protection of the present invention.

Industrial Applicability Embodiments of the present invention ensure that when a transient high power, continuous high power, wideband signal that may cause power amplifier damage occurs, the power amplifier is executed on the digital intermediate frequency link before the delayed transmitted signal is not output to the PA. Protection measures to effectively protect the amplifier.

Claims

Claim

 A method for protecting a power amplifier, comprising: performing delay processing and power detection processing on a digital signal to be transmitted; wherein, the duration of the delay processing is equal to the duration of performing the power detection processing;

 After detecting that the digital signal to be transmitted is abnormal, the part of the digital signal to be transmitted after the delay is turned off.

 2. The method of claim 1 wherein

 The performing power detection processing on the digital signal to be transmitted includes: performing single point power detection on the digital signal to be transmitted;

 The detecting that the digital signal to be transmitted is abnormal, includes:

 The power value of the at least one signal point of the digital signal to be transmitted is greater than a preset single point power threshold;

 And performing the shutdown processing on the abnormal part of the digital signal to be transmitted after the delay, including:

 The delayed digital signal to be transmitted is transmitted according to a fixed power value, or the signal point data whose power value is greater than a preset single-point power threshold is discarded.

 3. The method of claim 2, wherein

 Performing power detection processing on the digital signal to be transmitted, including: performing average power detection on the digital signal to be transmitted;

 The detecting that the digital signal to be transmitted is abnormal, includes:

 The average power value of the signal point in the digital signal to be transmitted is greater than a preset average power threshold;

 And performing the shutdown processing on the abnormal part of the digital signal to be transmitted after the delay, including:

 The power of the delayed digital signal to be transmitted is gradually reduced to zero and transmitted.

4. The method of claim 3, wherein The performing power detection processing on the digital signal to be transmitted includes: performing broadband signal detection on the digital signal to be transmitted;

 The detecting that the digital signal to be transmitted is abnormal, includes:

 The in-band noise floor power value other than the useful signal is greater than a preset wideband signal power threshold value; and the part of the digital signal to be transmitted after the delay is abnormally turned off, including:

 The power of the delayed digital signal to be transmitted is gradually reduced to zero and transmitted.

 5. The method according to claim 3 or 4, further comprising:

 After detecting that the digital signal to be transmitted returns to normal, the power of the delayed digital signal to be transmitted is increased step by step to the original transmit power and then transmitted.

 6. A device for protecting a power amplifier, comprising:

 a signal delay unit, configured to: delay processing the digital signal to be transmitted; wherein, the duration of the delay processing is equal to the duration of the power detection processing by the power detection processing unit; and the power detection processing unit is set to: The digital signal to be transmitted is subjected to power detection processing;

 The power amplifier protection execution unit is configured to: after the power detection processing unit detects that the digital signal to be transmitted is abnormal, perform a shutdown process on the abnormal portion of the digital signal to be transmitted after the delay.

 7. The apparatus according to claim 6, wherein

 The power detection processing unit includes a single-point power detecting unit, configured to: perform single-point power detection on the digital signal to be transmitted; and detect that a power value of at least one signal point in the digital signal to be transmitted is greater than When the preset single-point power threshold is used, it is determined that the digital signal to be transmitted is abnormal;

 The power amplifier protection execution unit is configured to: perform a shutdown process on a portion of the digital signal to be transmitted after the delay, including: transmitting the delayed digital signal after the delay according to a fixed power value, or Signal point data with a power value greater than the preset single-point power threshold is discarded.

8. The apparatus according to claim 7, wherein The transmitted digital signal is subjected to average power detection; when it is detected that the average power value of the signal point in the digital signal to be transmitted is greater than a preset average power threshold, it is determined that the digital signal to be transmitted is abnormal;

 The power amplifier protection execution unit is configured to: perform a shutdown process on the abnormal portion of the digital signal to be transmitted after the delay, including: reducing the power of the delayed digital signal to be transmitted to zero After the launch.

 9. The apparatus according to claim 8, wherein

 The power detection processing unit further includes a wideband signal detecting unit, configured to: perform broadband signal detection on the digital signal to be transmitted; and detect an out-band noise floor power value other than the useful signal is greater than a preset broadband When the signal power threshold is used, it is determined that the digital signal to be transmitted is abnormal;

 The power amplifier protection execution unit is configured to: perform a shutdown process on the abnormal portion of the digital signal to be transmitted after the delay, including: reducing the power of the delayed digital signal to be transmitted to zero After the launch.

 10. The apparatus according to claim 8 or 9, wherein

 The power amplifier protection execution unit is further configured to: after the power detection processing unit detects that the digital signal to be transmitted returns to normal, increase the power of the delayed digital signal to be transmitted to the original transmission step by step After power is emitted.