CN113055105A - High-precision VSWR (voltage-dependent stress) measurement method for remote radio unit - Google Patents
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Abstract
The invention discloses a high-precision VSWR (voltage standing wave ratio) measuring method for a remote radio unit, which defines two VSWR scheduling modes: when VSWR is smaller or higher and exceeds the PA protection threshold of the power amplifier, the Fast VSWR mode is operated, and the purpose that VSWR abnormity is found quickly and the PA protection process is triggered in time is achieved; when the VSWR is high but not exceeding the PA protection threshold, the VSWR monitoring system works in a Slow VSWR mode and aims to provide high-precision VSWR measurement, and Fast VSWR can quickly find the VSWR abnormity and trigger an alarm in time to take necessary PA protection measures; the Slow VSWR collects I/Q (In-phase/Quadrature) signals from a forward channel and a reverse channel, an autocorrelation matrix of a reflection signal is constructed according to a correlation estimation principle, a least square method is used for estimating a leakage coefficient of the forward signal, and then an In-band filtering and convolution filtering algorithm is used for eliminating a leakage component from the reflection signal, so that the VSWR measurement precision is effectively improved.
Description
Technical Field
The invention relates to the technical field of communication, in particular to a high-precision VSWR (voltage deviation) measuring method for a remote radio unit.
Background
For a Downlink channel (DL) of a Remote Radio Unit (RRU), one of the main functions is to perform Digital-to-Analog (D/a) conversion on a Digital signal, amplify the Digital signal by a PA, transmit the amplified Digital signal to an antenna port, transmit the amplified Digital signal to an antenna by a feeder, and finally radiate the amplified Digital signal in the form of electromagnetic waves into the air to establish communication with a mobile phone terminal.
An ideal rf system, which expects one hundred percent of the PA transmit to radiate energy to the antenna device, requires that the characteristic impedances and load impedances between the source, feed, antenna port connection remain precisely matched and that there is no leakage or interference during signal transmission.
However, there is no perfect end match in the real world. In a wireless system, impedance mismatching determined by hardware characteristics of a connecting device or impedance mismatching caused by objective reasons such as rusting, looseness, feeder damage and the like of an antenna port causes incident wave energy to be transmitted to an input end and not be completely absorbed, and part or all of the incident wave energy is reflected back to a transmitting end, so that PA (power amplifier) transmission is blocked, and service influences such as call drop, high error rate, cell coverage radius reduction and the like are generated. In severe cases, the PA is even burned out due to the accumulation of reflected energy.
VSWR is a scalar function of Return Loss (RL) and describes the impedance match of the power emitting source to the input. When the VSWR approaches 1.0, it means that the rf energy is totally radiated by the antenna, and there is no reflection and loss of energy. When the VSWR is infinite, it means that the energy is not radiated at all, i.e., total reflection. In the RRU system, the connection normality and the impedance matching among an antenna port, a feeder line and an antenna connection node can be determined by detecting VSWR.
The traditional VSWR measurement generally realizes digital power acquisition based on FPGA or SoC, then performs power gain compensation according to temperature, frequency point and attenuation of a link, calculates the analog power of an antenna port, and then calculates the VSWR value. Due to the limitation of hardware resources and the consideration of hardware cost, sample data used by the power acquisition is limited, a data processing model is simple, and the error and jitter of a measurement result are large.
VSWR measurement requires the isolation of the transmitted signal (forward path signal) from the reflected signal (reverse path signal) by means of a circulator that should be as close as possible to the antenna port. The circulator based on the circuit gain technology cannot achieve one hundred percent of signal isolation, and a small amount of transmission signals still leak into a reverse channel, so that the reflected power measurement value is inaccurate, and the VSWR measurement error is caused.
When the VSWR is large, the RRU triggers a VSWR alarm and reports the VSWR alarm to a BBU (Base Band Unit) or the RRU automatically enters a PA protection process, and the hardware protection purpose is achieved by deleting a carrier, closing the PA, and the like. However, the instantaneous VSWR is not large enough to damage the PA, and according to the RRU hardware design specification, the PA should be able to ensure that it normally operates for at least 1 minute without being damaged under the condition of total reflection at the antenna port (VSWR is infinite). In an actual application scenario, due to inaccuracy or excessive jitter of a VSWR measurement value, RRU often misreports a VSWR alarm, causing a cell to lose service or service capability to be reduced.
Disclosure of Invention
Aiming at the problems of low VSWR measurement precision, circulator signal leakage, false alarm and the like, the invention discloses a high-precision VSWR measurement method for a radio remote unit, and aims to eliminate circulator signal leakage errors, improve VSWR measurement precision and reduce VSWR alarm false alarm probability.
Meanwhile, the VSWR measurement speed and the calculation precision are comprehensively considered, two VSWR measurement methods are scheduled according to needs, the load balancing of the CPU is achieved, the robustness of the RRU is improved, and therefore the operation and maintenance cost of the base station is reduced.
In order to achieve the above object, the technical solution adopted by the present invention is that a high-precision VSWR measurement method for a remote radio unit defines two VSWR scheduling modes: fast VSWR and Slow VSWR; when the VSWR is smaller or exceeds the protection threshold of the PA, the method works in Fast VSWR mode, and when the VSWR is higher but does not exceed the protection threshold of the PA, the method works in Slow VSWR mode, and the method specifically comprises the following steps:
step 1: the following thresholds are predefined: a VSWR state machine working threshold, a VSWR forward power threshold, a VSWR slight alarm threshold, a VSWR serious alarm threshold, a PA protection alarm threshold, a VSWR alarm triggering frequency window and a VSWR alarm clearing frequency window;
step 2: a Fast VSWR working mode is started by default, Fast VSWR measurement is carried out, and weighted moving average filtering is carried out on the VSWR obtained through measurement;
and step 3: if the VSWR after filtering in the Fast VSWR working mode is less than or equal to the VSWR state machine working threshold, turning to the step 2, and continuing to measure the Fast VSWR; if the filtered VSWR meets the PA protection alarm threshold condition, the PA is closed; otherwise, stopping the Fast VSWR measurement, entering the next step, and starting the Slow VSWR working mode;
and 4, step 4: running a Slow VSWR, measuring the Slow VSWR, and performing weighted moving average filtering on the measured VSWR;
and 5: if the VSWR measured value after filtering in the Slow VSWR working mode is less than or equal to the VSWR state machine working threshold, stopping the Slow VSWR measurement, and turning to the step 2 to carry out Fast VSWR measurement again; otherwise, carrying out alarm detection;
step 6: alarm triggering detection;
and 7: and (5) alarm clearing detection.
Compared with the prior art, the invention has the following advantages:
1. two VSWR scheduling modes are defined: fast VSWR (a Fast VSWR measurement method with a slightly lower accuracy and higher efficiency) and Slow VSWR (a Slow VSWR measurement method with a slightly lower accuracy and lower efficiency). When VSWR is small or exceeds the PA protection threshold, the method works in Fast VSWR mode and aims to quickly find VSWR abnormity and trigger the PA protection mechanism in time. When the VSWR is high, but not beyond the PA inclusion threshold, it will operate in the Slow VSWR mode, aiming to provide a more accurate VSWR measurement.
2. The Fast VSWR is used as a default measuring method, the Forward channel Power (Forward Signal Power) and the Reverse channel Power (Reverse Signal Power) are directly collected from the FPGA or the SoC to rapidly calculate the VSWR, instantaneous jitter of a VSWR measuring value is restrained by combining Power detection and software filtering, and the method is suitable for a scene of total reflection or approximate total reflection. Fast VSWR aims at quickly finding VSWR anomalies, triggering alarms quickly to take necessary PA protection measures.
3. The Slow VSWR acquires I/Q signals from a Forward channel (FWD) and a backward channel (REV), constructs an autocorrelation matrix of a reflected signal and a cross-correlation vector of the backward signal and the Forward signal, estimates a leakage coefficient of the Forward signal by using a least square method, and eliminates a leakage component from the reflected signal by using the techniques of in-band filtering and convolution filtering so as to improve the VSWR measurement accuracy.
4. A weighted Moving Average filtering (WMA) is applied to reduce VSWR alarm false positive probability.
Drawings
Fig. 1 is a schematic diagram of a RRU uplink and downlink channel and a VSWR measurement principle in this embodiment.
FIG. 2 is a diagram illustrating the relationship between Return Loss and VSWR in this embodiment.
Wherein 1 is the elimination of leakage and interference from the back channel; 2 is the reverse channel grab point; 3 is the forward channel grab point; 5 is a reverse signal and a forward leakage signal; 6 is PA; 7 is the reverse power measurement channel; 8 is the forward feedback power measurement channel; 9 is a coupler; 10 is a circulator; 11 are FWD and REV switches; 12 is an analog filter; 13 is an antenna; 14 is a feed line; 15 is an antenna port.
Detailed Description
To facilitate understanding by those skilled in the art, the present invention will be further described with reference to the following detailed description, steps and drawings.
In order to reduce the operation complexity, the time domain correlation and convolution involved in the steps are multiplied by a Fast Fourier Transform (FFT) to a frequency domain, and then Inverse Fourier Transform (IFFT) is performed to a time domain.
xcorr(rev，fwd)＝IFFT(FFT(rev)·FFT(conj(fwd))
Where, conj is a conjugate function.
Assume a forward channel sampling rate of 307.2MHz and a reverse channel sampling rate of 153.6 MHz.
As shown in fig. 1 and fig. 2, the present invention discloses a high-precision VSWR measurement method for a remote radio unit, which defines two VSWR scheduling modes: fast VSWR and Slow VSWR; when the VSWR is smaller or exceeds the protection threshold of the PA, the method works in Fast VSWR mode, and when the VSWR is higher but does not exceed the protection threshold of the PA, the method works in Slow VSWR mode, and the method specifically comprises the following steps:
step 1: the following thresholds are predefined: a VSWR state machine working threshold, a VSWR forward power threshold, a VSWR slight alarm threshold, a VSWR serious alarm threshold, a PA protection alarm threshold, a VSWR alarm triggering frequency window and a VSWR alarm clearing frequency window;
step 2: a Fast VSWR working mode is started by default, Fast VSWR measurement is carried out, and weighted moving average filtering is carried out on the VSWR obtained through measurement;
and step 3: if the VSWR after filtering in the Fast VSWR working mode is less than or equal to the VSWR state machine working threshold, turning to the step 2, and continuing to measure the Fast VSWR; if the filtered VSWR meets the PA protection alarm threshold condition, the PA is closed; otherwise, stopping the Fast VSWR measurement, entering the next step, and starting the Slow VSWR working mode;
and 4, step 4: running a Slow VSWR, measuring the Slow VSWR, and performing weighted moving average filtering on the measured VSWR;
and 5: if the VSWR measured value after filtering in the Slow VSWR working mode is less than or equal to the VSWR state machine working threshold, stopping the Slow VSWR measurement, and turning to the step 2 to carry out Fast VSWR measurement again; otherwise, carrying out alarm detection;
step 6: alarm triggering detection;
and 7: and (5) alarm clearing detection.
The predefined thresholds in step 1 are shown in the following table:
the threshold value is only used for reference, and the actual value depends on the adaptation tolerance limit of the PA to the total reflection
The step 2 specifically comprises the following steps: powering on the RRU → hardware initialization → CPRI link synchronization → control management link establishment → carrier establishment → downlink gain control convergence → DPD (Digital Pre-Distortion) convergence → start Fast VSWR.
Step 2.1: switching the feedback switch to the reverse channel, and simultaneously sampling from FPGA or SoCIntegrating forward digital power and reverse digital power, denoted as P respectivelyfwd(dBFS)、Prev(dBFS)。
Step 2.2: calculating the incident power P of the antenna portfwd(dBm) and reflected power Prev(dBm)
Wherein
For gain compensation of forward channel temperature, frequency, attenuation,
gain compensation for back channel temperature, frequency, attenuation.
Step 2.3: if P isfwd(dBm). ltoreq.VSWR forward threshold, go to step 2.1. Otherwise, go to the next step.
Step 2.4: calculating the Return loss RLfast(dB) and
RELfast(dB)＝Pfwd(dBm)-Prev(dBm)
step 2.5: to the measured value
And performing weighted moving average filtering.
Wherein,
to be the VSWR average value before filtering,
w is the weight for the filtered new value.
And step 3: if it is not
Turning to step 2, the Fast VSWR measurement continues. If it is not
VSWR _ alarm _ number is satisfied consecutively times, triggering a PA protection alarm and shutting down the PA. If VSWR _ method _ threshold < VSWRfilterVSWR _ pa _ threshold, stop Fast VSWR measurement, go to the next step, start Slow VSWR.
Step 4.1: and (2) running a Slow VSWR (voltage source/frequency shift register), switching a feedback switch to a reverse channel, and simultaneously acquiring 2-millisecond I/Q (input/output) signals from a forward channel capture point and a reverse channel capture point within a CPRI (common public radio interface) 10ms basic frame period, wherein the I/Q signals are respectively 16 bits and are obtained according to a sampling rate: forward lane grab 38400 groups I/Q, noted
Wherein N is 38400; back channel grabbing 19200 groups I/Q, noted
Where M19200. To pair
Double oversampling, i.e. inserting a complex zero between every other I/Q: (0+ 0. j) to obtain
Step 4.2: calculating forward digital power RMSfwd(dBFS)
Step 4.3: the forward power calibration is limited in the range of (-infinity, -18dBFS), and the gain compensation of temperature, frequency and attenuation is carried out
If it is not
Go to step 4.1; otherwise, go to the next step.
Step 4.4: the signal component of the forward path leakage to the reverse path is estimated. First, an autocorrelation matrix R of the reflected signal is constructedxx
Where xcorr is the cross-correlation function and toeplitz is the function of the Topritz matrix generation.
Then, a cross-correlation matrix R of the reflected signal and the incident signal is constructedxy
Rxy＝Txy(1：64，N：N+64)
Finally, the least square method is used to solve the correlation coefficient Lfwd
Lfwd＝Rxx -1·Rxy
LfwdI.e. the estimation of the correlation coefficient of the forward signal leaking through the circulator to the reverse path.
Step 4.5: eliminating the leakage component of the forward channel signal from the reverse channel signal by convolution filtering algorithm to obtain
Where conv is a convolution function.
Step 4.6: to pair
In-band filtering, only the reflected signal within the forward path bandwidth is preserved. Suppose that the frequency point range of the downlink carrier is
Step 4.7: calculating the reverse signal
And performing Scale processing and gain compensation of temperature, frequency and attenuation to obtain
Step 4.8: slow VSWR calculation Return loss
And
step 4.9 analogous to step (07) pairs
Is filtered by weighted moving average to obtain
And 5: if it is not
Go to step 2 to make Fast VSWR measurement. If it is not
And continuously meeting VSWR _ alarm _ number times, reporting a PA protection alarm, and closing the PA. If it is not
The following steps are continued to detect a VSWR alarm.
Step 6: and (3) alarm triggering detection: if it is not
If the number of the continuous VSWR _ alarm _ number times is greater than the VSWR _ PA _ threshold, triggering a VSWR PA protection alarm; if it is not
If the number of the continuous VSWR _ alarm _ number is greater than the VSWR _ major _ threshold, triggering a VSWR serious alarm; if it is not
The number of consecutive VSWR _ alarm _ numbers is greater than VSWR _ minor _ threshold, a VSWR slight alarm is triggered.
And 7: alarm clearing detection: if it is not
If the number of the continuous VSWR _ alarm _ number times is greater than the VSWR _ PA _ threshold, triggering a VSWR PA protection alarm; if it is not
If the number of the continuous VSWR _ alarm _ numbers is less than the VSWR _ major _ threshold, clearing the VSWR serious alarm; if it is not
The number of consecutive VSWR _ alarm _ numbers is less than VSWR _ minor _ threshold, the VSWR slight alarm is cleared.
It should be understood that the above-described embodiments are only some of the embodiments of the present invention, and not all of them. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without any inventive step, are within the scope of the present invention.
Claims (17)
1. A high-precision VSWR (voltage distortion factor) measuring method for a remote radio unit is characterized by comprising the following steps: two VSWR scheduling modes are defined: fast VSWR and Slow VSWR; when the VSWR is smaller or exceeds the PA protection threshold, the VSWR monitoring device works in a Fast VSWR mode, and when the VSWR is higher but does not exceed the PA protection threshold, the VSWR monitoring device works in a Slow VSWR mode, and the method specifically comprises the following steps:
step 1: the following thresholds are predefined: a VSWR state machine working threshold, a VSWR forward power threshold, a VSWR slight alarm threshold, a VSWR serious alarm threshold, a PA protection alarm threshold, a VSWR alarm triggering frequency window and a VSWR alarm clearing frequency window;
step 2: starting a Fast VSWR working mode by default, carrying out VSWR measurement, and carrying out weighted moving average filtering on the VSWR obtained by measurement;
and step 3: if the VSWR measured value after filtering in the Fast VSWR working mode is less than or equal to the VSWR state machine working threshold, turning to the step 2, and continuing to carry out the Fast VSWR measurement; if the filtered VSWR meets the PA protection alarm threshold condition, the PA is closed; otherwise, stopping the Fast VSWR measurement, entering the next step, and starting the Slow VSWR working mode;
and 4, step 4: the Slow VSWR is operated, VSWR measurement is carried out, and weighted moving average filtering is carried out on the VSWR obtained through measurement;
and 5: if the VSWR measured value after filtering in the Slow VSWR working mode is less than or equal to the VSWR state machine working threshold, stopping the Slow VSWR measurement, and turning to the step 2 to carry out Fast VSWR measurement again; otherwise, carrying out alarm detection;
step 6: alarm triggering detection;
and 7: and (5) alarm clearing detection.
2. The high accuracy remote radio unit VSWR measurement method of claim 1, wherein: the step 2 specifically comprises the following steps:
step 2.1: switching the feedback switch to the reverse channel, and simultaneously acquiring the digital power of the forward channel and the digital power of the reverse channel from the FPGA or the SoC, wherein the digital powers are respectively marked as Pfwd(dBFS)、Prev(dBFS)；
Step 2.2: calculating the incident power P of the antenna port according to the channel gainfwd(dBm) and reflected power Prev(dBm)；
Step 2.3: if the incident power Pfwd(dBm) is less than the VSWR forward power threshold, then go to step 2.1; otherwise, entering the next step;
step 2.4: calculate the Return loss and VSWR, respectively, as RLfast(dB) and
step 2.5: for the above
Weighted moving average filtering is performed.
3. The method of claim 2, wherein the VSWR measurement is performed by a remote radio unit with high precision, comprising: the calculation method of the step 2.2 comprises the following steps:
wherein
Gain compensation of forward channel temperature, frequency and attenuation is carried out, and the unit is dB;
gain compensation for back channel temperature, frequency, attenuation in dB.
4. The method of claim 2, wherein the VSWR measurement is performed by a remote radio unit with high precision, comprising: the calculation method of the step 2.4 comprises the following steps:
RLfast(dB)＝Pfwd(dBm)-Prev(dBm)
wherein RLfast(dB) is the return loss, in dB,
is the VSWR value.
5. The method of claim 2, wherein the VSWR measurement is performed by a remote radio unit with high precision, comprising: the calculation method of the step 2.5 comprises the following steps:
wherein,
is the calculated average of the VSWR prior to filtering,
for the filtered new value, W is the weighting factor.
6. The high accuracy remote radio unit VSWR measurement method of claim 1, wherein: the step 4 specifically comprises the following steps:
step 4.1: switching a feedback switch to a reverse channel, simultaneously acquiring I/Q signals from a forward channel capture point and a reverse channel capture point in a common public radio interface CPRI (common public radio interface) 10 millisecond basic frame period, and performing oversampling processing on data of the reverse channel;
step 4.2: calculating forward digital power according to the forward access number;
step 4.3: calibrating the forward digital power, and performing gain compensation of temperature, frequency and attenuation to obtain the incident power of an antenna port; if the incident power is less than the VSWR forward power threshold, go to step 4.1; otherwise, entering the next step;
step 4.4: estimating a signal component leaked from a forward channel to a reverse channel, and solving a correlation coefficient by a least square method;
step 4.5: eliminating the leakage component of the forward channel signal from the reverse channel signal by a convolution filtering algorithm;
step 4.6: carrying out in-band filtering on the reflection signals after the convolution filtering, and only keeping the reflection signals in the bandwidth of a forward channel;
step 4.7: calculating reverse digital power, calibrating, and performing gain compensation of temperature, frequency and attenuation to obtain
Step 4.8: slow VSWR calculates Return loss and VSWR, denoted RL respectivelyslow(dB) and
step 4.9: for the above
Weighted moving average filtering is performed.
7. The method of claim 6, wherein the VSWR measurement is performed by a remote radio unit with high precision, comprising: the step 4.1 is specifically as follows:
switching a feedback switch to a reverse channel, and simultaneously acquiring 2-millisecond I/Q signals from a forward channel capture point and a reverse channel capture point in a common public radio interface CPRI (common public radio interface) 10-millisecond basic frame period, wherein the I/Q is assumed to be 16bit wide, the sampling rate of the forward channel is assumed to be 307.2MHz, and the sampling rate of the reverse channel is assumed to be 153.6 MHz; according to the sampling rate, the following results are obtained: forward channel acquisition 38400 sets of I/Q, noted
Wherein N is 38400; reverse channel Collection 19200 group of I/Q, noted
Wherein M19200; to pair
Double oversampling, i.e. inserting a set of complex zeros (0+ 0. j) between every other set of I/Q, results in
8. The method of claim 6, wherein the VSWR measurement is performed by a remote radio unit with high precision, comprising: the specific forward digital power calculation formula of the step 4.2 is as follows:
wherein I and Q are respectively real part and imaginary part of I/Q signal, N is 38400, RMSfwd(dBFS) is forward digital power in dBFS.
9. The method of claim 6, wherein the VSWR measurement is performed by a remote radio unit with high precision, comprising: the step 4.3 is specifically as follows:
the forward power calibration is limited in the range of (-infinity, -18dBFS), and the gain compensation of temperature, frequency and attenuation is carried out
Wherein
Gain compensation of forward channel temperature, frequency and attenuation is carried out, and the unit is dB;
the unit is dBm for the antenna port incident power after calibration and gain compensation.
10. The method of claim 6, wherein the VSWR measurement is performed by a remote radio unit with high precision, comprising: the step 4.4 is specifically as follows:
first, an autocorrelation matrix, denoted as R, of the reflected signal is constructedxx，
Wherein xcorr is a cross-correlation function, toeplitz is a Topritz matrix generating function, and (N: N +64) represents a sequence with subscript positions between N and N + 64;
then, a cross-correlation matrix R of the reflected signal and the incident signal is constructedxy
Rxy＝Txy(1：64，N：N+64)
Finally, the least square method is used to solve the correlation coefficient Lfwd；
Lfwd＝Rxx -1·Rxy
Wherein R isxx -1Is RxxInverse of the matrix, LfwdI.e. the estimation of the correlation coefficient of the forward signal leaking through the circulator to the reverse path.
11. The method of claim 6, wherein the VSWR measurement is performed by a remote radio unit with high precision, comprising: the calculation formula of the step 4.5 is as follows:
where conv is a function of the convolution,
i.e. the sequence of reflected signals after the leakage signal has been cancelled.
12. The method of claim 6, wherein the VSWR measurement is performed by a remote radio unit with high precision, comprising: in the step 4.6:
the frequency point range of the downlink carrier is assumed to be
The in-band filtering method is:
wherein, the FFT is discrete Fourier transform, the IFFT is discrete inverse Fourier transform,
namely, is a pair
The in-band filtered signal sequence, i.e. the in-band reflected signal after the leakage interference has been cancelled.
13. The method of claim 6, wherein the VSWR measurement is performed by a remote radio unit with high precision, comprising: in the step 4.7:
wherein RMSrev(dBFS) is the reverse channel digital power,
the digital power of the reverse channel after calibration and gain compensation.
14. The method of claim 6, wherein the VSWR measurement is performed by a remote radio unit with high precision, comprising: in the step 4.8:
wherein RLslow(dB) is the return loss, in dB,
is the VSWR value.
15. The method of claim 6, wherein the VSWR measurement is performed by a remote radio unit with high precision, comprising: in the step 4.9:
where WMA is a moving average function.
16. The high accuracy remote radio unit VSWR measurement method of claim 1, wherein: the step 6 specifically comprises the following steps:
if the filtered VSWR measurement value in the Slow VSWR mode of operation
If the number of the continuous VSWR alarm triggering time window is greater than the PA protection alarm threshold, triggering a PA protection alarm; if it is not
If the number of the continuous 'VSWR alarm triggering time window' is greater than 'VSWR serious alarm threshold', triggering a VSWR serious alarm; if it is not
If the number of consecutive VSWR alarm triggering times window is greater than the VSWR slight alarm threshold, then a VSWR slight alarm is triggered.
17. The high accuracy remote radio unit VSWR measurement method of claim 1, wherein: the step 7 specifically comprises the following steps:
if the filtered VSWR measurement value in the Slow VSWR mode of operation
If the number of the continuous VSWR alarm clearing time window is less than the PA protection alarm threshold, clearing the PA protection alarm; if it is not
If the number of the continuous 'VSWR alarm clearing frequency window' is less than 'VSWR serious alarm threshold', clearing the VSWR serious alarm; if it is not
And if the number of the continuous 'VSWR alarm clearing time window' is less than the 'VSWR slight alarm threshold', clearing the VSWR slight alarm.
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| CN115021841A (en) * | 2022-08-08 | 2022-09-06 | 南京典格信息技术有限公司 | Radio frequency system PIM monitoring and eliminating method based on Schmidt orthogonalization |
| CN116819508A (en) * | 2023-08-28 | 2023-09-29 | 烟台初心航空科技有限公司 | Radar positioning and ranging method based on TDR |
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