WO2013063735A1

WO2013063735A1 - Adaptive control method of repeater output signal, device thereof, and system

Info

Publication number: WO2013063735A1
Application number: PCT/CN2011/081541
Authority: WO
Inventors: 宋伯炜; 李文华; 夏劲松; 赵振华; 范莹莹
Original assignee: 苏州全波通信技术有限公司
Priority date: 2011-10-31
Filing date: 2011-10-31
Publication date: 2013-05-10
Also published as: CN102792742A; CN102792742B

Abstract

An adaptive control method of a repeater output signal, a device thereof, and a system in the technical field of communications. In the adaptive control method, quality of a repeater output signal is detected; after signal quality calculation, a signal quality indication value is compared with a signal quality threshold, and dynamic power control is performed according to a comparison result. The present invention combines the echo cancellation technology, the signal quality monitoring, and the adaptive power adjustment, so as to ensure maximum output power in the case of exceeding the preset signal quality threshold at the same time of effectively avoiding self-excitation of a repeater, thereby improving the coverage effect of the repeater, and finally achieving self-consistent working between repeaters in a supplementary point network.

Description

Adaptive control method for output signal of repeater, device and system thereof

The invention relates to a method and device in the field of communication technology, in particular to an adaptive control method for an output signal of a repeater, an apparatus and a system thereof.

Background technique

With the rapid development of modern information technology, new generations of mobile communication technologies, as well as digital TV and mobile TV terrestrial broadcasting technologies, have higher requirements for wireless signal coverage. Mobile communication networks and broadcast networks often encounter many difficulties in order to achieve good signal coverage. High-rise buildings, geographical environment, mountain occlusion, lake and sea reflections, etc. in large and medium-sized cities often cause some coverage of weak signal areas and blind areas. Due to its low investment, simple structure and convenient installation, the repeater has been widely used in some weak signal areas or signal blind areas, and has become an important choice for wireless network optimization.

As a radio transmission relay device that plays a signal enhancement role in wireless communication transmission, the repeater is a radio frequency power booster. Traditional repeaters, classified according to the type of transmit power control, can be divided into two categories: The first type is a fixed gain repeater, which is commonly used in the telecommunications industry. Its main feature is that the automatic level control (AGC) range of the input signal is relatively small (such as about 15 dB), and the power gain of the output signal and the input signal is relatively fixed. For example, for a repeater with a maximum output power of 10 dBm, a maximum gain of 60 dB, and an AGC range of 15 dB, if the input signal is -75 dBm, assuming a signal power of -60 dBm after AGC, then After amplification, the maximum output signal power is about 0 dBm, which is equivalent to 1 W. If the input signal is -50 dBm, the maximum output signal power after amplification is about 10 dBm, which is equivalent to 10 W, and so on. It can be seen that the nominal indicator of this type of repeater is not a fixed output power, but a maximum gain value, and its actual output power will vary with the magnitude of the input power. Another type of repeater can be called a fixed power repeater, which is commonly used in the broadcasting industry. Within a certain input power range, the output power remains constant regardless of the input power. For example, a repeater with a nominal power of 100 W will have a constant output power of 100 W as long as the input power is still within the AGC range.

With a fixed gain repeater, since the power of the input RF signal of the repeater often fluctuates due to various factors, when the input signal is weak, the output power will become small correspondingly, and may not reach the installation. The demand for coverage is fixed at the station; however, when the input signal is very strong and the output signal is amplified by equal gain, it may cause the amplifier module in the repeater to operate in a nonlinear region, affecting the quality of the transmitted signal. When the input signal fluctuates greatly, the stability of the coverage effect using the fixed gain repeater may not be guaranteed.

Fixed-power repeaters also have their shortcomings. Since the output power cannot be changed according to the input power variation, the rated power output is maintained even when the main tower signal is weak, so if part of the RF signal is emitted from the transmitting antenna Leaking into the receiving antenna and receiving it again will form an echo to the repeater. The echo signal and the useful signal transmitted by the main tower enter the repeater for cyclic amplification, which will cause the repeater to self-oscillate.

Therefore, it can be seen that power control and self-excitation avoidance become a problem that the repeater needs to solve. Traditionally, repeater products or technologies have done a lot of work around how to avoid these problems. There are two common practices. The first is to improve the isolation between the transceiver antennas. If the isolation is not guaranteed, the power of the repeater must be retracted to avoid self-excitation. However, this method needs to be repeatedly tested at the construction site, and the adjustment is based on the experience of use. Due to various environmental conditions, the limitations of the improvement are great, and the difficulty and cost of the construction are high. What is more serious is that the test data can only reflect the state of the construction installation at that time, and cannot be adjusted in real time for various factors such as changes in environmental factors in the future, or neighboring new main towers or repeaters. The other is to add echo cancellation (ics) to the repeater. The core of echo cancellation is the estimation of the echo channel. Currently, there are various mature channel estimation methods, such as LMS algorithm, NLMS algorithm, RLS algorithm and so on. Its role is based on physical isolation, reducing the margin required to be retained and expanding the gain range of the repeater. However, in the case of strong echoes, even if the echo is effectively eliminated, the quality of the output signal is seriously impaired, so that although the signal strength received by the terminal in the area to be compensated is strengthened, the terminal receiving effect is still not improve. For example, in the telecommunications industry, after the signal blind zone is added, the mobile phone signal is full, but the phone is still unable to connect or the communication quality is unstable.

This is because people are too concerned about the isolation and self-excitation of the repeater, ignoring the ultimate goal of adding a repeater to improve coverage, in order to improve the quality of the received signal of the terminal, thus ensuring the transmission of the repeater itself. Signal quality is the most critical. The signal quality of the repeater itself is not the result of a single factor, which is influenced and constrained by multiple factors, including the received signal strength and signal quality of the main tower, and the echo strength of the repeater. , even the dynamic range of the input gain control of the front end of the repeater and so on. For example, the dynamic range of the AGC at the input end of the repeater is relatively limited (generally only 50 dB). When the mixed signal is processed at the front end of the repeater, the effective range of the main signal is greatly squeezed due to the presence of strong echoes. The signal quality is seriously damaged. Even after echo cancellation, post-amplification or even filtering, the lost signal quality cannot be recovered, so the output signal is still better than the signal quality of the input signal. Seriously worse. This is equivalent to the final amplification of the repeater, which is a noise signal with considerable power, and these relatively strong noises are undoubtedly worsening the reception and coverage of the signal dead zone where the original main signal is weaker. This is the reason why there is an empirical value constraint on the power and quantity of the repeater in the coverage of a main tower in the project. Because the introduction of repeaters is often thought to introduce interference to the main tower and existing repeaters, resulting in a deterioration in overall signal quality. This interference will increase as the output power of the repeater increases and the number of repeaters increases. When a plurality of repeaters are adjacent to each other, mutual interference with each other will thus cause the coverage to deteriorate severely. Therefore, it is absolutely necessary to focus on the actual signal quality when designing and operating the repeater.

For the echo cancellation technology, after searching for the prior art, Chinese Patent Document No. CN102045098A, published On May 4, 2011, the "fast convergence adaptive method based on power control in ICS repeater" is described. Its main feature is to install an adjustable attenuator to control the output power after the repeater power amplifier. In the initial stage of echo cancellation, the maximum attenuation value of the attenuator is such that the output power of the repeater is at the lowest value within the set range, so that the repeater does not self-excitation, ensuring that the LMS channel estimation process can proceed normally; The estimation gradually converges, the echo cancellation starts to work normally, and then the attenuation value is gradually reduced at a fixed time interval and a fixed adjustment value, and finally the output power of the repeater is restored to the rated power.

However, this technique has certain limitations: it only serves as a way to accelerate the convergence of the channel estimator, and therefore belongs to an optimization of the echo cancellation technique. However, it is only applied to the initialization of the repeater, and there is no mention of dynamic, real-time tracking and adjustment of the subsequent environmental conditions and operating conditions of the repeater. In addition, the maximum attenuation value of the attenuation value, the adjusted adjustment interval and the adjustment step size are related to the specific repeater and environmental conditions. If the setting is improper, the channel estimator may be unstable. Last but not least, as mentioned above, this technique does not focus on the quality of the transmitted signal. Even after the echo is removed, the quality of the output signal is not guaranteed.

In response to the problem of the isolation of the repeater, further search found that the Chinese Patent Document No. CN1777074B, published on May 5, 2006, describes the "method of detecting the isolation of the wireless repeater by using the pilot multipath signal", which is built in The monitoring module reads the carrier-to-interference ratio of the pilot signal of the main path and the carrier-to-interference ratio of the multipath signal, and detects the isolation margin at any time to protect the repeater from being in a state of insufficient isolation margin.

However, this technology does not introduce echo cancellation technology (ICS) into the system. When it is easy to detect self-excitation, it is recommended to take measures to reduce the gain, etc., so that the coverage of the repeater is directly limited by the isolation. In addition, this technique is limited by the calculation of the carrier/dry ratio Ec/Io by pilot, which is inapplicable to communication systems that do not have pilot signals. It is mentioned in the text that "the accuracy of this test method is affected when the isolation margin signal is mixed with the multipath signal on the donor receiving path", and actually exists on both the main receiving path and the echo path. Multipath will not be able to distinguish the source of multipath normally, so its accuracy, reliability and practicability are not guaranteed, and it is not suitable for widespread application in engineering applications.

In addition, Chinese Patent Document No. CN1627661A, published on the date of 2005-6-15, describes an "adaptive wireless repeater" for mobile communication signals, the technology comprising: a working path, a detection path and a control path The working process is: generating a reference signal, using the in-band idle channel to transmit and receive the reference signal through the antenna of the working path, and then mixing the reference signal originally generated by the mixer of the detecting channel and the frequency synthesizer The control processing unit of the control channel is entered, and finally the monitoring processing unit issues a control signal to adjust the gain of the amplifier of the working channel, thereby implementing an adaptive function of the adaptive wireless repeater. This technique calculates the isolation between the transmitting and receiving antennas by transmitting a reference signal to adjust the gain of the upper and lower working channel amplifiers to achieve automatic control of the isolation.

Although this technique takes into account the problem of automatic detection of antenna isolation and thus adaptive adjustment of the repeater gain, it also does not introduce echo cancellation technology, so it can only be regarded as a kind of isolation integrated in the repeater. The automatic measurement method is equivalent to adaptive gain based on the timing measurement. The adjustment replaces the manual adjustment in the traditional sense and does not eliminate the isolation. Degree constraint on the repeater; secondly, the work of this technology requires additional equipment (standard signal source), and the reference signal is transmitted when the in-band idle channel needs to be occupied, and the pre-adaptation phase of the reference level generation needs to be turned off. The channel is used to obtain level measurement results, so the accuracy of the measurement and the real-time tracking are limited. Finally, like all other technologies, the invention does not pay attention to the quality of the signal transmitted by the repeater.

Summary of the invention

The present invention is directed to the above-mentioned deficiencies of the prior art, and provides an adaptive control method for a repeater output signal, a device and a system thereof, combined with echo cancellation technology, signal quality monitoring and adaptive power adjustment, effectively avoiding direct release While the station is self-excited, it guarantees the maximum output power above the preset signal quality threshold, which is beneficial to extend the coverage of the repeater, improve the coverage of the repeater, and finally form a straight-line network. Self-consistency between the stations.

The invention is achieved by the following technical solutions:

The invention relates to an adaptive control method for output signals of a repeater. By detecting the quality of the output signal of the repeater, after the signal quality is calculated, the signal quality characterization value is compared with a preset signal quality threshold, and the comparison is performed according to the comparison. As a result, dynamic power control is achieved.

The signal quality calculation may be to calculate different types of signal quality characterizations such as signal to noise ratio (S/N), carrier to noise ratio (C/N), modulation error rate (MER), and the like. The signal to noise ratio refers to the ratio of the useful signal power to the noise power in the baseband signal. The modulation error rate is a model that characterizes the signal-to-noise ratio in a mathematical model. It refers to the power ratio between the ideal signal and the error vector generated after the signal is damaged. The carrier-to-noise ratio refers to the useful signal power in the spectrum of the RF signal. The ratio of noise power. As described in the article "Relationship between RF Carrier-to-Noise Ratio and Video Signal-to-Noise Ratio", "There will be some gain in the demodulation process, but the gain factor will be equally applicable to the signal and noise, and the SNR obtained for each channel will be approximated. It is the same as the (C/N) REC calculated above. "And when the damage is noise, in theory, SNR and MER are equal and numerically equal to (C/N) RE _C ". Therefore, it can be considered that the signal-to-noise ratio, the carrier-to-noise ratio, and the modulation error rate are different in different fields (baseband or radio frequency). The exact exchange of specific values needs to be studied in depth according to the specific situation, but it tends to be practical in practical applications. The values are considered to be similar. Therefore, the present invention only completes the signal quality calculation description by taking the most common signal to noise ratio calculation process as an example.

The calculation of the signal-to-noise ratio means that the output signal of the repeater is used as the received signal, and the restored data D' is obtained by down-conversion processing and then subjected to demodulation processing including _: filter, clock synchronization processing and frequency synchronization processing. n), finally using (but not limited to) auxiliary data estimation, based on known data, ie auxiliary data estimation of the training sequence, M ₂ M ₄ algorithm based on blind estimation to obtain the signal to noise ratio value. The signal-to-noise ratio value can also be obtained by connecting the RF signal output from the repeater (or the down-conversion operation signal) to the general-purpose demodulation chip.

The auxiliary data estimation refers to: performing hard decision on the data D′(n) recovered after demodulation according to a modulation method to obtain data D ₀ '(n) is subtracted to obtain signal noise E(n), that is, E(n) = D'(n)- D. '(n);

Then, E(n) is projected onto the I and Q axes to obtain the I component and the Q component (11) and £ ₍₃ (11) of the noise signal, respectively. The total noise power Ρ„. _ϊβ = ∑^·(£,(τ ² + ^(η:) ² where: _η represents the serial number of the sampled value, Ν represents the number of total sampled values;

Similarly, the power of the received signal i> _{sl ne is} calculated from the data after the decision.

Where: and is the I component and Q component of the data after the decision, then the corresponding signal to noise ratio is S/N = lO x log( P _{siana /} /P _noise ) _{> the} unit is dB.

The auxiliary data estimation based on the known data refers to: when the transmitted data contains a periodically repeated known pseudo-random sequence, the decompressed restored data D'(n) and the ideal data D _{e can be} (n) performing asynchronous correlation, and implementing PN segment data transmission and reception synchronization according to the relevant characteristics of the PN sequence;

Then note that the PN segment signal noise is E _PN (n), then there is E _PN (n) = D _PN '(n) - D _PN() (n), where: D _PN '(n), D _PN0 (n) Refers to the data of the PN segment;

Similarly, the noise power at the PN end is 13⁄4„.^ =∑ ^ £ _/ ^(11:) ² + £ _/ ^ 01) ² ), the signal power at the PN end is

Pm _3igna i

Signal SNR

S/N = 10 X log( P _sl . _ffna , /P _noise ) in dB.

The M ₂ M4 algorithm based on blind estimation means that the data D′(n) recovered after demodulation can be obtained as an estimated value of the corresponding second-order matrix and fourth-order matrix expressed as M ₂ = ^∑ ^ |i)'(n)| ² , M ₄ = ∑^ |D'( )| , then according to the M ₂ M4 algorithm, there is P _s , then the signal SNR is

S/N = 10 X log( P _signal /P _noise ) in dB.

The general-purpose demodulation chip calculates the signal-to-noise ratio, specifically: by decoupling the radio frequency signal outputted by the repeater (or the signal after the down-conversion operation) with the tuner (or signal input end) of the demodulation chip. Chip signal input, the demodulation chip completes demodulation and signal-to-noise ratio calculation by controlling the operation of the demodulation chip, and directly reads out the signal-to-noise ratio value of the current signal through a specific pin or protocol of the demodulation chip. The dynamic power control refers to: using the average signal quality V _Q as an input,

- Q, _hresh . _Ld ) Calculate the power control variable V _P , where: Q, _hresh . _Ld is the preset signal quality threshold; V _P is the power control variable of the previous moment, and its initial value can be zero; a is the multiplication factor, and its sign bit is related to the characteristics of the power amplifier module and the power control mode in the repeater. , among them:

When V _P . is zero, V _P =ax(V _Q - Q _thresh _ld ), the power control variable is directly proportional to the signal quality variable; when V _Q - Q, _hresheld difference is positive, Representing that the current average signal quality is below the signal quality threshold, so the output signal power has a margin for further amplification;

When V _Q - Q _ihresh . _{When the ld} difference is negative, it means that the current average signal quality is lower than the signal quality threshold, so the output signal power needs to be adaptively adjusted to ensure that the output signal quality meets the requirements;

When a is set to a positive value, the output power of the repeater is positively related to V _P ; otherwise a is set to a negative value. Replacement page (Article 26) The signal quality threshold is determined by any of the following methods: a) recalling a pre-stored empirical value by a memory in the quality control unit of the read signal detection module, for example, under 64QAM modulation, the white noise threshold is about 24 dB, Therefore, in order to avoid the cliff effect of the digital signal, the signal quality threshold can be set to 28 dB (safe margin of 4-6 dB above the threshold) and stored in the memory;

b) manually adjust the threshold and update the pre-stored value in the memory through the interaction module. For example, the receiver is not ideal in the field, and the signal quality threshold can be controlled by means such as panel control, serial communication interface control, or network control. Modify and update the pre-stored values in memory.

The invention relates to an implementation device of the above method, comprising: an output module including a transmitting antenna and a signal quality detecting module connected thereto, wherein: the output module receives the echo-detected and echo-removed signals output by the echo canceling system, After power amplification and band pass filtering, the RF signal is output to the transmitting antenna to complete the transmission, and the output module simultaneously receives the power control variable outputted by the signal quality detecting module as a control variable, and the signal output by the transmitting antenna is simultaneously returned to the input end of the signal quality detecting module. .

The signal quality detecting module comprises: a quality detecting unit and a quality control unit, wherein: the input end of the quality detecting unit is connected to the transmitting antenna and receives the radio frequency signal, and the output end of the quality detecting unit is connected with the quality control unit and outputs signal quality characterization The variable, the output of the quality control unit is connected to the output module and outputs a power control variable.

The quality detecting unit comprises: a down conversion module, a demodulation module and a signal to noise ratio detection module, wherein: the input end of the down conversion module receives the radio frequency signal from the transmitting antenna, and the output end of the down conversion module is connected to the demodulation module and After the frequency conversion signal is output, the demodulation module demodulates the converted signal and outputs the restored data to the signal to noise ratio detection module. The signal to noise ratio detection module calculates the signal quality and outputs it to the quality control unit.

The quality detecting unit can also be implemented by a general-purpose demodulation chip. At this time, the input end of the demodulation chip receives the radio frequency signal from the transmitting antenna (or the signal after the down-conversion operation), and simultaneously performs demodulation processing and signal quality characterization calculation. Finally, the output signal quality is characterized by a variable to the quality control unit.

The quality control unit comprises: an averaging module, a memory module and a quality calculation module, wherein: the averaging module receives and averages the signal quality characterization variables output by the quality detecting unit, and the quality calculation module respectively receives the average signal quality from the averaging module and comes from The signal quality threshold of the memory module and the output power control variable to the output module, the output signal quality is adaptively controlled to the output power.

The output module comprises: a power amplification module, a band pass filter and a transmit antenna, wherein: the power amplification module receives the power control variable output by the signal quality detection module, and receives the echo detection and back from the output of the echo cancellation system. After the wave is cancelled, the signal is subjected to power amplification processing with loop control, and the band pass filter receives the power amplified signal and performs shaping filtering, and then outputs the signal to the transmitting antenna for RF signal output, and the transmitting antenna output signal is simultaneously cited. Go back to the input of the signal quality detection module. The invention relates to a repeater with adaptive signal adjustment, comprising: a receiving antenna, a low noise amplifier, an automatic gain control, an echo canceling system and an adaptive control module as described above.

The receiving antenna receives a mixed signal including a main tower signal and an echo signal, and the mixed signal passes through a front-end low-noise amplifier and automatic gain control, and performs echo detection and echo cancellation operations through an echo cancellation system, and then sends the signal. The power amplification module of the output module of the adaptive control module performs power amplification, and then passes through a band-pass filter shaping filter, and finally outputs a radio frequency signal from the transmitting antenna of the output module, thereby realizing the function of RF power enhancement.

The echo cancellation system includes: an echo detection module and an echo cancellation module, wherein: an input end of the echo cancellation module is respectively connected to an output of the automatic gain control and the echo detection module, and respectively receives the amplified mixed signal And the echo signals under the current channel are subtracted and output to the output module and the echo detection module respectively, and the input ends of the echo detection module are respectively connected with the output antennas of the output module and the output of the echo cancellation module, and respectively receive the radio frequency The signal and the subtracted processed signal of the echo cancellation module are detected by digital signal processing techniques to estimate the echo signal under the current channel.

The digital signal processing technique refers to: a minimum error approximation of the LMS algorithm, an NLMS algorithm, an RLS algorithm, or an asynchronous correlator or a combination thereof for estimating the current echo channel model to obtain an echo signal under the current channel.

The echo cancellation system plays the role of echo cancellation in the repeater of the present invention, so that the effect of using the original physical isolation can be achieved without using physical isolation, or the current physical isolation is simple. , to achieve the effect of exceeding the current physical isolation limit, thus reducing the possibility of self-excited oscillation of the repeater, and reducing the difficulty of construction.

The output module comprises: a power amplification module, a band pass filter and a transmit antenna, wherein: the power amplification module receives the power control variable output by the signal quality detection module, and receives the echo detection and back from the output of the echo cancellation system. After the wave is cancelled, the signal is subjected to power amplification processing with loop control, and the band pass filter receives the power amplified signal and performs shaping filtering, and then outputs the signal to the transmitting antenna for RF signal output, and the transmitting antenna output signal is simultaneously cited. Go back to the input of the signal quality detection module.

The power amplifying module can adopt a power adjustable amplifier and directly implement the power control variable outputted by the signal quality detecting module as a control signal; or control the variable attenuator by using a power control variable, and then control the fixed power through the variable attenuator. Amplify the output of the module to achieve power control changes.

The invention has a built-in signal quality detecting module, so that the output signal quality can be measured without additional testing equipment, and the output signal quality is quickly and intuitively characterized, so that no special professional equipment can be carried in the construction for testing during construction, which facilitates engineering installation and Debugging, monitoring and alarming can be realized by remote control, etc. It has real-time performance and greatly improves the safety factor of the repeater.

Secondly, the present invention combines the echo cancellation technology, and the existing and mature echo cancellation technology can make the effect of using the original physical isolation without using physical isolation, or the current physical isolation is simple. The effect of exceeding the current physical isolation limit is achieved, thus greatly reducing the possibility of self-excited oscillation of the repeater and reducing the difficulty of construction. Furthermore, the RF output power of the present invention is adaptively variable, unlike a constant gain in a fixed-gain repeater that can only be linearly varied according to the magnitude of the input power, unlike a fixed power repeater that can only have a constant power. The transmission is adaptively adjusted according to the loop control of the transmitted signal quality, so that the output power can be increased as much as possible within a preset range.

The most important and core point is that the repeater can be adaptively adjusted to ensure that the output signal quality is above the preset threshold. Unlike the conventional method, which only cares about the output power of the repeater, or the margin of the antenna isolation, the present invention accurately detects the quantized index of the output signal quality and compares it with the threshold. Therefore, there is no such thing as the effective signal of the input is completely submerged under the strong echo or noise, and the output power is even larger, the shoulder ratio is higher, or the echo is successfully eliminated, and the final amplified output is only the most noise signal. This in turn causes interference to the main tower and the repeater that is already working properly.

Furthermore, the real-time detection and adaptive adjustment mechanism of the repeater of the present invention contributes to the self-consistency of the entire patch network. Because the repeater of the present invention does not require manual intervention, and is not limited to the engineering installation period, it can be adaptively adjusted in real time and continuously according to the situation in the work site. This is especially helpful for networking systems where multiple repeaters are deployed in a large area to achieve blind coverage. Because the power and signal quality of the newly added repeater often interfere with the existing repeater when adding the repeater in the past, the traditional experience requires repeated adjustment of the output power of each repeater to achieve equalization, while at the same time The ratio of the number of stations to the main tower should not be too high, adding a lot of limitations to the design of the patch network. If the repeater in the entire complementary network has the function of adaptively adjusting the output power according to the signal quality, not only the quality of the output signal is guaranteed, but also no artificial noise, and between the repeater and the main tower. The formation of a self-consistent system makes the location selection greatly simplified, which is extremely beneficial for a large number of projects.

Finally, the structure of the repeater in the present invention is versatile, and can be widely applied to various broadcast television standards (such as ATSC/MH, DVB-T/H, ISDB-T, CTTB/DTMB, CMMB, etc.), and It is suitable for various telecommunication standards (WCDMA, GSM, CDMA2000, etc.) through simple duplex transformation, and thus has broad application prospects.

DRAWINGS

Figure 1 is a schematic diagram of the structure of a communication system.

2 is a schematic structural view of a quality detecting unit and a quality control unit.

Figure 3 is a schematic diagram of the echo cancellation mechanism.

Figure 4 is a schematic diagram of the application of the embodiment.

detailed description

The embodiments of the present invention are described in detail below. The present embodiment is implemented on the premise of the technical solution of the present invention, and the detailed implementation manner and the specific operation process are given. However, the protection scope of the present invention is not limited to the following implementation. example.

Example

As shown in FIG. 1, the embodiment relates to a repeater with adaptive signal adjustment, comprising: a receiving antenna, a low noise amplifier, an automatic gain control, an echo cancellation system, and an adaptive control module connected in sequence. The adaptive control module includes: an output module including a transmitting antenna and a signal quality detecting module connected thereto, wherein: the output module respectively receives the echo signal detected by the echo canceling system and the useful signal after echo cancellation And the signal quality detection module output power control variable, after power amplification and band pass filtering, respectively output signals to the transmitting antenna to complete the RF signal output, and at the same time lead back to the input end of the signal quality detecting module.

The signal quality detecting module comprises: a quality detecting unit and a quality control unit, wherein: the input end of the quality detecting unit is connected to the transmitting antenna and receives the radio frequency signal, and the output end of the quality detecting unit is connected with the quality control unit and outputs the signal signal noise. Comparing, the output of the quality control unit is connected to the output module and outputs a comparison result of the signal-to-noise ratio and the signal quality threshold.

As shown in FIG. 2, the quality detecting unit includes: a down conversion module, a demodulation module, and a signal to noise ratio detection module, wherein: an input end of the down conversion module receives a radio frequency signal from a transmitting antenna, and an output end of the down conversion module The demodulation module is connected and outputs the converted signal. The demodulation module demodulates the converted signal and outputs the restored data to the signal to noise ratio detection module. The signal to noise ratio detection module outputs the signal to noise ratio to the quality control unit.

The down conversion module comprises: a frequency converter, a fixed filter and an analog to digital converter, wherein: the frequency converter receives the radio frequency signal from the transmitting antenna, and the output end of the frequency converter outputs the downconverted signal to the fixed filter, fixed After filtering, the filter outputs the filtered analog signal to an analog-to-digital converter for analog-to-digital conversion. The output of the analog-to-digital converter is connected to the demodulation module and outputs the converted and filtered digital signal.

The demodulation module comprises: a filter, an interpolator and a phase reversor connected in sequence, wherein: the filter is connected to the output end of the down conversion module and receives the downconverted digital signal, and the output end of the filter The input end of the interpolator is connected and the filtered digital signal is output, and is interpolated by the interpolator and output to the phase derotator for phase reversal.

The filter filters out the high-order spectrum harmonics after the analog-to-digital conversion, and completes the matched filtering function, and outputs the filtered baseband digital signal; the interpolator is used to recover the sampling clock phase, and output the sampled clock phase corrected data; The phase derotator is used to recover the carrier frequency and phase, and the demodulated signal after the output frequency phase is corrected is sent to the input end of the signal to noise ratio detection module.

The SNR detection module adopts any of the following structures according to different SNR calculation modes: a) The SNR detection module includes: a noise signal generation module and a SNR calculation module, where: noise signal generation The module receives the signal output by the demodulation module and obtains a difference between the output signal of the demodulation module and the signal after the decision by means of - al) demodulation decision; or

A.2) The asynchronous correlation of the training sequence realizes that the transmitted and received signals are synchronized with each other to obtain the difference.

The noise signal is calculated and output to the signal to noise ratio calculation module, and the signal to noise ratio calculation module combines the output signals of the demodulation module and separately calculates the values of the power of the signal and the noise and obtains a signal to noise ratio;

b) Under the signal-to-noise ratio estimation mode without specifically obtaining the noise signal, the signal-to-noise ratio detection module can directly calculate or read the signal-to-noise ratio value of the current output signal according to the specific adoption technology, and send it to the quality control unit. The quality control unit comprises: an averaging module, a memory module and a quality calculation module, wherein: the averaging module receives the signal to noise ratio output by the signal to noise ratio detection module of the quality detecting unit, and the quality calculation module respectively receives the average signal from the averaging module The noise ratio and the signal quality threshold from the memory module are output and the power control variable is output to the output module to perform adaptive control of the output signal quality on the output power.

The averaging module uses the arithmetic mean of the signal-to-noise ratio of the output signal obtained in the time window of length τ as the average signal-to-noise ratio; by changing the value of τ, the tracking speed and power stability can be balanced.

The length of the time window τ is a pre-stored value from the memory module or is manually adjusted by the interaction module and updates the pre-stored value in the memory.

The memory module uses on-chip storage resources of a digital signal processor or uses off-chip storage resources.

The quality calculation module is based on an average signal to noise ratio V _Q and a signal quality threshold Q _thresh output by the memory module. _Ld as the input signal, calculate the power control variable V _P by V _P =V _p .+(XX(VQ - Qth„ _sh _ld ) and output it to the output module to complete the power adaptive control, where: V _P . is the previous one The power control variable of the moment, its initial value can be zero; (is the multiplication factor; when V _P . is zero, V _P =<xx(VQ - Q _tosh _ld ), the power control variable is directly linear with the signal quality variable Proportional relationship; when the difference of V _Q - Qa^Md is positive, it means that the current signal quality is higher than the signal quality threshold, so the output signal power has a margin for further amplification;

When V _Q - Qth _resh . _{When the ld} difference is negative, it means that the current signal quality is lower than the signal quality threshold, so the output signal power needs to be adaptively adjusted to ensure that the output signal quality meets the requirements;

When α is set to a positive value, the output power of the repeater is in a positive relationship with V _P ; otherwise a is set to a negative value.

The signal quality detecting module is configured to perform real-time detection of signal quality on the transmitted signal. The input is the output RF signal drawn back from the transmitting antenna, and the signal quality variable V _{Q is} calculated and sent to the quality control module to generate the power control variable V _P . There are many different standards for measuring signal quality. Common indicators include signal-to-noise ratio (S/N), carrier-to-noise ratio (C/N), modulation error rate (MER), etc., where: SNR refers to baseband The ratio of received signal power to noise power in the signal.

For example, after transmitting a modulated signal, after demodulation, the output power of the received signal is measured as P _signal (dBm), then the demodulated signal is removed, and the noise output power is recorded as P _n . _Ise (dBm), then S/N = 10 x log( F _s ^ _!Qi P _3⁄4i} ^) , in dB. The carrier-to-noise ratio refers to the ratio of the received signal power to the noise power in the spectrum of the RF signal before demodulation.

There is a certain correspondence between the signal-to-noise ratio, the carrier-to-noise ratio, and the modulation error rate. The present invention only uses the signal-to-noise ratio as an example for description, and the purpose of achieving the signal quality detection by the remaining indicators is also within the scope of the present invention. Inside.

The way that the power control variable is sent to the output module for power control may be to use a power adjustable amplifier as the power amplification module, and the power control variable is directly input as its control signal, as shown in FIG. 4(a), or may be power control. The variable controls a variable attenuator, and the power variation of the output of the power amplifying module is realized by the variable attenuator, as shown in Fig. 4(b).

The output module includes: a power amplification module, a band pass filter, and a transmit antenna, where: the power amplification module is connected Receiving the useful signal from the echo cancellation output of the echo cancellation system and the power control variable output by the signal quality detection module, and performing power amplification processing with loop control, and the band pass filter receives the power amplified signal and performs the signal After shaping and filtering, output to the transmitting antenna for RF signal output;

The signal quality detecting module receives the amplified RF signal that is sent back by the transmitting antenna and performs real-time signal quality detection, generates a power control variable by using the detected signal quality, and sends the power control variable to the power amplification module of the output module, thereby finally forming The loop of the power feedback control is completed by the output signal quality.

The power amplification module adopts a power adjustable amplifier and directly implements a power control variable outputted by the signal quality detection module as a control signal; or controls a variable attenuator by using a power control variable, and then controls the fixed power through a variable attenuator. Amplify the power output of the module output.

The receiving antenna receives a mixed signal including a main tower signal and an echo signal. After the mixed signal is passed through a front-end low-noise amplifier and automatic gain control, the echo cancellation operation is completed by the echo cancellation system, and then sent to the adaptive control module. The power amplification module of the output module performs power amplification, and then filters and filters through a band pass filter, and finally outputs a radio frequency signal from a transmitting antenna of the output module, thereby realizing the function of RF power enhancement.

As shown in FIG. 3, the echo cancellation system includes: an echo detection module and an echo cancellation module, wherein: an input end of the echo cancellation module is respectively connected to an output of the automatic gain control and the echo detection module, and respectively Receiving the amplified mixed signal and the echo signal under the current channel are subtracted and output to the output module and the echo detecting module respectively, and the input ends of the echo detecting module are respectively connected with the transmitting antenna and the echo canceling module and respectively receive the RF The signal and the subtracted processed signal of the echo cancellation module are detected by digital signal processing techniques to estimate the echo signal under the current channel.

The digital signal processing technique refers to: a minimum error approximation of an LMS algorithm, an NLMS algorithm, an RLS algorithm, or an asynchronous correlator or a combination thereof for estimating a current echo channel model.

For example, the article "A Mobile TV Repeater Echo Cancellation Implementation" proposes an LMS-based echo cancellation implementation using retransmission signals, as shown in Figure 2. The implementation process is as follows: d(n) is the signal received by the receiving antenna, including the useful signal and echo signal transmitted by the main tower. The signal x(n) drawn back from the transmitting antenna is divided into two ways, one channel is used for channel estimation, the current echo channel impulse response c(n) is obtained, and the other channel is simulated from the echo channel by the estimated channel impulse response. Interfering with the signal y(n), and subtracting the received signals d(n) and y(n) to obtain a difference e(n), which is to continuously adjust the tap coefficients of the channel impulse response, so that c(n) is closer to the real channel. At the same time, e(n) is also a pure signal that is filtered to remove noise, and finally transmitted by the transmitting antenna. The technique described in this article is done in the digital domain, where n is an arbitrary integer.

The echo cancellation module may be any echo cancellation technology, for example, in the digital domain, through the digital add/subtractor, to complete the separation of the received signal and the echo signal, or in the analog domain, The analog device completes the operation. The implementation of echo cancellation operations can be done in baseband, low IF, and even RF. The echo cancellation module shown in Figure 2 is performed in the baseband digital domain. Otherwise, the y(n) value can be first converted to the analog domain by digital simulation, if no changes are made. Frequency operation, then equivalent to echo cancellation in the baseband analog domain, otherwise according to the frequency band after the frequency conversion, echo cancellation at low intermediate frequency or radio frequency.

As shown in Figure 4, the implementation process of this device is as follows -

1. After the repeater is activated, the receiving antenna receives a mixed signal containing the main tower signal and the echo signal. The mixed signal passes through the front-end low-noise amplifier (LNA) and is then subjected to automatic gain control (AGC) to adjust the power of the mixed signal to the optimal receive range of the repeater's subsequent processing block (eg -50 dBm).

2. The power adjusted mixed signal is sent to the echo cancellation system. At the beginning of the system, the echo detection module has a gradual convergence process. For example, using the LMS algorithm, the difference between the actual value and the estimated value drives the echo channel estimation until the echo channel estimate is infinitely close to the real channel. The echo cancellation module subtracts the estimated echo from the mixed signal to achieve echo cancellation.

3. After the echo cancellation signal passes through the power amplifier, it is output to the transmitting antenna. At the same time, the transmitted signal is led back from the transmitting antenna to the signal quality detecting module.

4. The signal quality detection module uses the selected signal quality measurement indicators to perform signal quality detection on the transmitted signal. Record the preset signal quality threshold as . , . The specific value of _ld is related to the selected signal quality metric. a) When V. _{When ld} , it means that the current signal quality is already below the threshold, whether it is because the echo cancellation system has not reached the convergence state, causing the echo that is not completely eliminated to affect the signal quality, or because the strong echo causes the front-end AGC to saturate and thus echo. Before the elimination, the signal quality is affected, and the output signal power needs to be adaptively adjusted down. At this time, the power is reduced. Under the same isolation, the echo ratio is reduced and the AGC saturation condition is also improved. The signal quality is still calculated in real time, resulting in a new variable value V _Q . Calculate again ¥ ₍₃ and 0 ₀ _ ₁₁ . _{1 (1} difference. b) If ¥ ₍₃ and 0 ₁₁₁₁ ^ ₁₁ . _{1 (1 when the} difference starts to become positive, it means the current power adjustment strategy is valid) The signal quality is picked up. At this time, the current power can be continuously output, and the signal quality is continuously detected. If the V _Q and _.ld differences are still negative, the difference is further reduced, indicating that the current power adjustment direction is correct, but the adjustment is made. The amplitude is not enough, the output signal power can be further reduced, and the signal quality can be detected in real time until v _Q and QthM _Sh . The _ld difference starts to become a positive number.

c) ¥ ₍₃ and 0 ₁₁₁₁ ^ ₁₁ . _{1 (1 When the} difference is positive, it means that the current signal quality is already above the threshold. At this time, the system is in a stable state, and the output signal quality is ideal. You can set a certain value at this time. Offset threshold ( _.ffset ). For example when

The value obtained by VQ is positive, which means there is still a certain margin in the current signal quality. If you want to achieve greater coverage, you can further amplify the output signal power and detect the signal quality in real time to ensure that it is always higher than the threshold.

5. The signal quality module always keeps the signal quality in real time during the whole repeater operation, and adaptively adjusts the output gain of the repeater through the power control variable to ensure the maximum possible power under certain output signal quality. Overlay Cover range.

In the actual application environment, when the signal intensity of the main tower received by the receiving antenna of the repeater is -70 dBm, the modulation error rate (MER) of the main tower signal is about 18 dB, and the echo arriving at the receiving antenna is - 45 dBm, that is, if the echo intensity is 25 dB, then the mixed signal received by the receiving antenna is still approximately equal to the current echo signal strength - 45 dBm. If the current best input range of the repeater is -45 dBm (the noise floor is -80 dBm), then the AGC of the front end will not perform any amplification on the mixed signal, so the received signal is still -70 dBm, then With a noise floor of -80 dBm, only 10 dB of useful shoulders are left in the received signal, so the MER is also below 10 dB. Even after echo cancellation and back-end power amplifier, the output received signal shoulder will not be compensated, so the signal MER will be much lower than the original main tower signal of 18 dBo. At this time, if the repeater still has the rated output power If it is transmitted (assuming a rated output power of 20 dBm (100 W)), then directly transmitting a high-power noise signal of approximately 200 W, which is a strong co-channel interference for the weak main tower signal in the region, will eventually affect Receive the signal quality received by the terminal.

In the same case, the repeater of this embodiment (assuming that the MER threshold of the output signal is set to 15 dB in advance). When it is detected that the MER of the output signal is below the threshold, the repeater will automatically reduce the transmit power, for example to 10 dBm (10 W), so that the echo signal arrives at the receive antenna while the rest of the conditions are unchanged. It is approximately -55 dBm and the mixed signal power is also -55 dBm. At this point, the AGC amplifies the mixed signal by 10 dB for the best range, so the received signal power is -60 dBm, which is 20 dB above the noise floor. After the echo cancellation and the post-stage power amplifier, the output signal of the repeater may still maintain a high MER (for example, 17 dB) above the predetermined threshold. At this point, if you need to further expand the coverage, you can also increase the output signal gain, and finally achieve a balance between signal power and signal quality.

Claims

Claim

1. An adaptive control method for a repeater output signal, characterized in that, by detecting a quality of a output signal of a repeater, a signal quality characterization value is compared with a signal quality threshold after signal quality calculation, and is compared according to As a result, dynamic power control is achieved.

2. The adaptive control method according to claim 1, wherein the signal quality calculation comprises: a signal to noise ratio calculation and/or a carrier to noise ratio calculation and/or a modulation error rate calculation.

The adaptive control method according to claim 1 or 2, wherein the calculation of the signal-to-noise ratio in the signal quality calculation refers to using the output signal of the repeater as the received signal, and then performing the down-conversion process and then the solution. The recovered data is obtained by the restored data D'(n), and finally the auxiliary data estimation is used, based on the known data, that is, the auxiliary data estimation of the training sequence or the signal-to-noise ratio detection calculation of the M ₂ M ₄ algorithm based on the blind estimation, and the signal is obtained. Signal to noise ratio.

4. The adaptive control method according to claim 3, wherein the demodulation processing comprises: filtering, clock synchronization processing, and frequency synchronization processing.

The adaptive control method according to claim 3, wherein the auxiliary data estimation refers to: performing hard decision on the data D'(n) recovered after demodulation according to a modulation method to obtain data D. '(n) subtracts to get the signal noise E(n), ie E(n)= D'(n)- D ₀ '(n);

Then project E(n) onto the I and Q axes to get the I and Q components (11) and £ ₍₃ (11) of the noise signal respectively, then the total noise power. ^ =:∑:^(£ , («) ² + 3⁄4(«) ² )- where: η represents the serial number of the sampled value, and Ν represents the number of total sampled values;

Similarly, the power of the received signal is calculated by the data after the decision _ηα|

+ O {nf), where: and are the I and Q components of the data after the decision, then the corresponding signal to noise ratio is

S / = 10 X log{ P _sisimi U , the unit is dB.

The adaptive control method according to claim 3, wherein the auxiliary data estimation based on the known data refers to: when the transmitted data includes a periodically repeated known pseudo-random sequence, The data D'(n) recovered after demodulation is matched with the ideal data D. (n) Perform asynchronous correlation, realize PN segment data transmission and synchronization according to the relevant characteristics of the PN sequence; then record the PN segment signal noise as E _PN (n), then there is E _PN (n) = D _PN '(n)- D _PN . (n), where: D _PN '(n), D. _PN (n) refers to the data of the PN segment; Similarly, the PN-end noise power is /^^ww =∑^( E _p (n) ² ÷ E _F (n) ² }, and the PN signal power is

PpN^ai =∑^!( l> _m ( + B _Pm(j (n ), then get the signal to noise ratio

■S/ = ίθ X log( P _s1⁄2?! «i/P _Ha;iff ), in dB.

The adaptive control method according to claim 3, wherein the M ₂ M ₄ algorithm based on blind estimation refers to: the data recovered after demodulation is '(n), and the corresponding Second-order matrix and fourth-order matrix

The adaptive control method according to claim 2 or 3, wherein the signal-to-noise ratio detection calculation is implemented by a dedicated demodulation chip, specifically: by transmitting a radio frequency signal or down-converting a repeater After operation, the signal is connected to the tuner or signal input end of the demodulation chip as a signal input of the demodulation chip. By controlling the operation of the demodulation chip, the demodulation chip completes demodulation and signal-to-noise ratio calculation, and passes through a specific pin of the demodulation chip or Protocol, directly read out the signal-to-noise ratio value of the current signal.

9. The adaptive control method according to claim 1, wherein said dynamic power control means: using an average signal quality V _Q as an input, via V _P =V _P .+ax(V _Q - Q _Toesh _ld ) calculates the power control variable V _P , where: Q _toesh . _Ld is the preset signal quality threshold, ν _Ρ is the power control variable of the previous moment, and its initial value can be zero. (It is the multiplication factor, and its sign bit is related to the characteristics of the power amplifier module and the power control mode in the repeater. Where - when V _P . is zero, V _P =<xx(VQ - Q _tosh _ld ), the power control variable is directly proportional to the signal quality variable; when the V _Q - Qa^Md difference is positive At the time, it represents that the current average signal quality is higher than the signal quality threshold, so the output signal power has a margin for further amplification;

When V _Q - Qth _resh . _{When the ld} difference is negative, it means that the current average signal quality is lower than the signal quality threshold, so the output signal power needs to be adaptively adjusted to ensure that the output signal quality meets the requirements;

The adaptive control method according to claim 1 or 9, wherein the signal quality threshold is determined by any of the following methods:

a) recalling the pre-stored empirical value by the memory in the quality control unit of the read signal detection module;

b) Manually adjust the threshold and update the pre-stored value in the memory through the interaction module.

The adaptive control method according to claim 10, wherein said mode a) means that the white noise threshold is about 24 dB under 64QAM modulation, so in order to avoid the cliff effect of the digital signal, The signal quality threshold can be set to 28 dB (safe margin of 4-6 dB above the threshold) and stored in memory.

The adaptive control method according to claim 10, wherein the mode b) is: the receiving condition is not ideal in the field, and can be controlled by, for example, panel control, serial communication interface, or network. Control, etc., modify the signal quality threshold and update the pre-stored value in the memory.

13. An adaptive control module for a repeater output signal, comprising: an output module including a transmit antenna and a signal quality detection module coupled thereto, wherein: the output module respectively receives the output of the echo cancellation system The received signal after echo detection and echo cancellation and the power control variable output by the signal quality detection module are respectively outputted to the transmitting antenna to complete the RF signal output after power amplification and band pass filtering, and are returned to the signal quality detecting module. Input.

The adaptive control module according to claim 13, wherein the signal quality detecting module comprises _{: a} quality detecting unit and a quality control unit, wherein: the input end of the quality detecting unit is connected to the transmitting antenna and receives the radio frequency The signal, the output of the quality detecting unit is connected to the quality control unit and outputs a signal quality representation, and the output of the quality control unit is connected to the output module and outputs a power control variable.

The adaptive control module according to claim 14, wherein the quality detecting unit comprises: a down conversion module, a demodulation module, and a signal to noise ratio detection module, wherein: the input end of the down conversion module receives the The RF signal of the transmitting antenna, the output end of the down-conversion module is connected with the demodulation module and outputs the converted signal, and the demodulation module demodulates the converted signal and outputs the restored data to the signal-to-noise ratio detection module, and the signal-to-noise ratio The detection module calculates the signal quality characterization and outputs it to the quality control unit.

The adaptive control module according to claim 15, wherein the down conversion module comprises: a frequency converter, a fixed filter, and an analog to digital converter, wherein: the frequency converter receives the radio frequency signal from the transmitting antenna, The output of the inverter outputs the down-converted signal to the fixed filter, and the fixed filter performs filtering processing, and then outputs the filtered analog signal to the analog-to-digital converter for analog-to-digital conversion, and the output of the analog-to-digital converter is connected to the demodulation module. And output the frequency conversion and the filtered digital signal.

The adaptive control module according to claim 15 or 16, wherein the demodulation module comprises: a filter, an interpolator and a phase derotator connected in sequence, wherein: the filter and the down converter The output end of the module is connected and receives the downconverted digital signal, and the output end of the filter is connected to the input end of the interpolator and outputs the filtered digital signal. The interpolator performs interpolation processing and outputs it to the phase reverser for phase derotation.

The adaptive control module according to claim 17, wherein the filter filters out high-order spectrum harmonics after analog-to-digital conversion, and completes a matching filtering function, and outputs the filtered baseband digital signal; The interpolator is used to recover the sampling clock phase, and output the phase corrected data of the sampling clock; the phase derotator is used to recover the carrier frequency and phase, and the demodulated signal after the output frequency phase is corrected is sent to the signal to noise ratio detection module. Input.

The adaptive control module according to claim 14, 15 or 18, wherein the signal to noise ratio detection module adopts any of the following structures according to different signal to noise ratio calculation modes: a) The noise ratio detection module comprises: a noise signal generation module and a signal to noise ratio calculation module, wherein: the noise signal generation module receives the signal output by the demodulation module and obtains a demodulation module output signal and a post-decision signal by means of - al) demodulation decision Difference; or

b) Under the SNR estimation mode without specifically obtaining the noise signal, the SNR detection module can directly calculate or read the signal-to-noise ratio value of the current output signal according to the specific technology, and send it to the quality control unit.

The adaptive control module according to claim 14, 15 or 19, wherein the quality control unit comprises: an averaging module, a memory module and a quality calculation module, wherein: the averaging module receives the signal of the quality detecting unit The signal-to-noise ratio of the signal output by the noise ratio detection module, the quality calculation module respectively receives the average signal-to-noise ratio from the average module and the signal quality threshold from the memory module and outputs the power control variable to the output module to complete the output signal quality to the output. Adaptive control of power.

The adaptive control module according to claim 20, wherein the averaging module uses an arithmetic mean value of an output signal SNR obtained in a time window of length T as an average signal to noise ratio; By changing the value of T, the tracking speed and power stability can be balanced.

22. The adaptive control module according to claim 21, wherein the length T of the time window is a pre-stored value from the memory module or is manually adjusted by the interaction module and the pre-stored value in the memory is updated.

23. The adaptive control module of claim 20, wherein the memory module uses a digital signal The on-chip storage resources of the processor or the use of off-chip storage resources.

24. The adaptive control module of claim 20, wherein the quality calculation module is based on an average signal to noise ratio V _Q and a signal quality threshold Q _thresh output by the memory module. _{Ld is} used as the input signal, and the power control variable V _{P is} calculated by V _P =V _p .+(XX(VQ - Qth _resh _ld ) and output to the output module to complete the power adaptive control, where: V _P . is the last moment The power control variable, whose initial value can be zero; (is the multiplication factor;

When V _P . is zero, V _P =<xx(VQ - Q _tosh _ld ), the power control variable is directly proportional to the signal quality variable; when the V _Q - Qa^Md difference is positive, Representing that the current signal quality is higher than the signal quality threshold, so the output signal power has a margin for further amplification;

When the difference of V _Q - Qfl^Md is negative, it means that the current signal quality is lower than the signal quality threshold, so the output signal power needs to be adaptively adjusted to ensure that the output signal quality meets the requirements;

The adaptive control module according to claim 13, wherein the output module comprises: a power amplification module, a band pass filter, and a transmit antenna, wherein: the power amplification module receives the output from the echo cancellation system. The received signal after echo cancellation and the power control variable output by the signal quality detecting module are subjected to power amplification processing with loop control, and the band pass filter receives the signal after power amplification processing, performs shaping filtering, and outputs the signal to the transmitting antenna. RF signal output;

The signal quality detecting module receives the amplified RF signal received by the transmitting antenna and performs real-time signal quality detection, generates a power control variable by using the detected signal quality variable, and sends the power control variable to the power amplification module of the output module, and finally A loop is formed that performs power feedback control by output signal quality.

The adaptive control module according to claim 25, wherein the power amplifying module adopts a power adjustable amplifier and directly implements a power control variable output by the signal quality detecting module as a control signal; or adopts power The control variable controls a variable attenuator and then controls the power output of the fixed power amplifier module through a variable attenuator.

27. A repeater having adaptive signal conditioning, comprising: a receiving antenna, a low noise amplifier, an automatic gain control, an echo canceling system, and any of claims 13-26 Adaptive control module.

The repeater according to claim 27, wherein the receiving antenna receives a mixed signal including a main tower signal and an echo signal, and the mixed signal passes through a front-end low noise amplifier and automatic gain control. Echo cancellation system The echo cancellation operation is completed, and then the power amplification module of the output module of the adaptive control module is completed to perform power amplification, and then filtered by a band pass filter, and finally the RF signal is outputted from the transmitting antenna of the output module, thereby realizing RF power enhancement. Features.

The repeater according to claim 27 or 28, wherein the echo cancellation system comprises: an echo detection module and an echo cancellation module, wherein: the input ends of the echo cancellation module are respectively and automatically The gain control is connected to the output of the echo detection module and respectively receives the amplified mixed signal and the echo signal under the current channel for subtraction processing and respectively output to the output module and the echo detection module, and the input ends of the echo detection module respectively The signal is connected to the transmitting antenna and the echo cancellation module and receives the RF signal and the subtracted processed signal of the echo cancellation module respectively, and the digital signal processing technology is used to detect and estimate the echo signal under the current channel.

30. The repeater according to claim 29, wherein said digital signal processing technique is: a minimum error approximation of an LMS algorithm, an NLMS algorithm, an RLS algorithm or an asynchronous correlator or a combination thereof for estimating Present the current echo channel model.