JP4878893B2 - Wireless device - Google Patents

Description

  The present invention relates to a radio apparatus and a gain control method, and more specifically, a radio apparatus that performs automatic gain control (hereinafter referred to as AGC) on a signal from a mobile terminal apparatus in a mobile communication system, and The present invention relates to a gain control method for optimizing the gain convergence speed of AGC in such a wireless device.

  2. Description of the Related Art In recent years, mobile communication systems (for example, Personal Handy phone System: hereinafter referred to as PHS), which are rapidly developing, are adapted to an adaptive array in a radio reception system on a base station side when communicating between a base station and a mobile terminal device. A method of extracting a signal from a desired mobile terminal device by processing has been proposed.

  Adaptive array processing is based on the received signal from the mobile terminal apparatus, calculating a weight vector composed of reception coefficients (weights) for each antenna of the base station and adaptively controlling it to remove interference components and This is processing for accurately extracting a signal from the mobile terminal device.

Adaptive array processing requires a plurality of antennas that are spatially distributed, that is, array antennas. For example, in an array antenna composed of two antennas, the array output signal Y (t) when the received signals at each antenna are X1 (t) and X2 (t) and the weights at each antenna are W1 and W2, respectively. It looks like this:
Y (t) = W1X1 (t) + W2X2 (t)
When the signal from the desired mobile terminal apparatus is S1 (t) and the signal from the mobile terminal apparatus serving as the interference source is S2 (t), the received signal of each antenna is as follows:
X1 (t) = H11S1 (t) + H12S2 (t) + n1 (t)
X2 (t) = H21S1 (t) + H22S2 (t) + n2 (t)
Here, H11 represents the propagation path characteristic from the desired mobile terminal apparatus to the antenna 1, and H12 represents the propagation path characteristic from the mobile terminal apparatus serving as the interference source to the antenna 1. H21 represents the propagation path characteristic from the desired mobile terminal apparatus to the antenna 2, and H22 represents the propagation path characteristic from the mobile terminal apparatus serving as the interference source to the antenna 2. n1 (t) represents noise in the receiving system of the antenna 1, and n2 (t) represents noise in the system of the antenna 2. The array output at this time is as follows:
Y (t) = (W1H11 + W2H21) S1 (t)
+ (W1H21 + W2H22) S2 (t)
+ W1n1 (t) + W2n2 (t)
Suppose we can calculate a weight that satisfies the following formula:
(W1H11 + W2H21) = 1
(W1H21 + W2H22) = 0
Thus, the array output signal is:
Y (t) = S1 (t) + n (t)
However, n (t) = W1n1 (t) + W2n2 (t).

  Therefore, by calculating an appropriate weight by adaptive array processing, it is possible to remove an interference component and receive a signal from a desired mobile terminal apparatus.

  FIG. 11 functionally describes a radio apparatus that is provided for each antenna in a conventional base station that performs adaptive array processing using such a plurality of antennas and performs AGC on a signal from a mobile terminal apparatus. FIG. 12 is a flowchart showing a gain control method for optimizing the gain convergence speed of AGC in such a radio apparatus.

  First, referring to FIG. 11, a signal received from antenna 1 is amplified by AGC amplifier 2, and is detected by in-phase component (I component) and quadrature component (Q component) by quadrature detector 3. ) And then stored in the memory 4.

  The IQ signal once stored in the memory 4 is given to the demodulation circuit 5. The demodulation circuit 5 also receives IQ signals from other antennas (not shown), performs the above-described adaptive array processing and demodulation processing, and extracts signals from each mobile terminal device.

  The reception level detection device 6 obtains the reception level of the signal from the IQ signal stored in the memory 4. For example, the amplitude value of the IQ signal is calculated between the 60th symbol and the 8th symbol of the received signal of each frame. The maximum amplitude value among these 8 symbols is the reception level in the frame.

The feedback data calculator 7 calculates feedback data for determining the amplification factor of the AGC amplifier 2 in the next frame based on the reception level obtained by the reception level detection device 6 and the step constant stored in the memory 9. Here, when the reception level obtained by the reception level detection device 6 is P_max, the predetermined target value is P_ideal, and the step constant is Step, the feedback data at the time of reception of the next frame from the feedback data at the time of reception of the previous frame. The amount of change ΔFB to the feedback data can be calculated by the following formula:
ΔFB = (P_max−P_ideal) / 2 Step
Therefore, assuming that the value of feedback data at the time of receiving the previous frame is FB, the feedback data FB ′ at the time of receiving the next frame is expressed as follows:
FB ′ = FB−ΔFB
The feedback data calculated by the feedback data calculator 7 is temporarily stored in the memory 8. The stored feedback data is read out in the next frame and given to the gain control input of the AGC amplifier 2 to be reflected in the AGC when the next frame is received.

  Next, a gain control method for optimizing the gain convergence speed of AGC in the radio apparatus shown in FIG. 11 will be described with reference to FIG. The following processing is realized by software by a digital signal processor (DSP) of the wireless device.

  First, in step S1, a signal from the mobile terminal apparatus is subjected to quadrature detection. Here, the RXIF signal, which is an intermediate frequency signal received from the mobile terminal apparatus, is converted into an RXIQ signal subjected to quadrature detection.

  In step S2, a symbol for starting detection of a reception level of a signal from the mobile terminal apparatus is set. Here, an example is shown in which the reception level is detected from the 60th symbol of the received signal.

  In step S3, it is determined whether or not the current symbol is a symbol period in which the reception level of the signal from the mobile terminal apparatus is detected. For example, when the reception level is detected in the 8 symbol period from the 60th symbol to the 67th symbol, if the symbol whose amplitude is to be calculated is before the 68th symbol, the amplitude of the symbol is calculated. Move to processing, otherwise move to processing to calculate feedback data.

  In step S4, the amplitude of the symbol is calculated. A value obtained by squaring the I component of the IQ signal and a value obtained by squaring the Q component are added. Here, in order to simplify the process, the process for obtaining the square root of the added value is not performed.

  In step S5, it is determined whether or not the amplitude A calculated in step S4 is larger than the maximum amplitude A_max stored so far.

  If it is determined in step S6 that A is greater than A_max in step S5, A_max is replaced with A.

  In step S7, the symbol whose amplitude is calculated is advanced to the next symbol.

  In step S8, the amount of change in feedback data is calculated from the maximum amplitude value from the 60th symbol to the 67th symbol and a fixed step constant stored in the memory.

  In step S9, feedback data in the next frame is calculated, and the calculated feedback data is reflected in the AGC when the next frame is received.

  In adaptive array processing, signals received from a plurality of antennas are multiplied by weights, and weights are calculated such that the power of interference components is reduced when they are combined. The operation of multiplying the weights is an operation of appropriately adjusting the amplitude and phase of the signal received from each antenna. Therefore, if the amplitude information or phase information of the received signal is erroneous due to waveform distortion or the like, the adaptive array processing cannot exhibit sufficient performance.

  On the other hand, in a general amplifier, when a certain level is output in the input / output characteristics, saturation occurs and a nonlinear region occurs. For this reason, for example, when calculating feedback data based on the fixed step constant as described above, the distance between the base station and the mobile terminal device, the presence or absence of an obstacle, and fading, etc. If the reception level of the signal from the mobile terminal apparatus fluctuates greatly due to the influence, the base station amplifier (AGC amplifier 2) enters this non-linear region, resulting in distortion in the received waveform, and as a result, adaptive array processing is performed. There was a problem that it would not function properly.

  Therefore, an object of the present invention is in an environment where the reception level of a signal from a mobile terminal apparatus varies greatly due to the influence of the distance between the base station and the mobile terminal apparatus, the presence or absence of an obstacle, and fading. Another object of the present invention is to provide a radio apparatus and a gain control method capable of performing adaptive array processing without causing an amplifier to perform non-linear operation.

The present invention is a radio apparatus that performs AGC on a signal from a terminal apparatus, and comprises gain control feedback means for applying AGC to a signal in accordance with the signal level, and the gain control feedback means includes past feedback. First gain control means for supplying first feedback data for slowly converging the signal level to a target value based on a difference from the data, and a signal based on a correspondence table of received signal strength and feedback data Second gain control means for supplying second feedback data for rapidly converging the level of the signal to the target value, received signal strength detecting means for detecting the received signal strength of the signal from the terminal device in the wireless device, and the received signal A field for selecting the first feedback data or the second feedback data according to the detection result of the intensity detecting means. Feedback data switching means.

According to another aspect of the present invention, there is provided a gain control method in a radio apparatus that performs AGC on a signal from a terminal apparatus, comprising the step of performing AGC on a signal according to the level of the signal, The applying step includes a first step of supplying first feedback data for slowly converging the signal level to the target value based on a difference from the past feedback data, and a correspondence table between the received signal strength and the feedback data. A second step of supplying second feedback data for rapidly converging the signal level to the target value based on the signal level, and detecting the received signal strength of the signal from the terminal device in the wireless device; and Selecting the first feedback data or the second feedback data according to the result.

  According to the present invention, the reception level is converged to the target value by appropriately controlling the convergence speed of the AGC even in an environment where the reception level greatly fluctuates due to the influence of fading or signal reception of a new mobile terminal. It becomes possible.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

[Embodiment 1]
FIG. 1 is a functional block diagram functionally illustrating a radio apparatus according to Embodiment 1 of the present invention, and FIG. 2 is a flowchart showing a gain control method according to Embodiment 1 of the present invention.

  The radio apparatus shown in FIG. 1 is the same as the radio apparatus shown in FIG. 11 except for the following points. That is, the radio apparatus shown in FIG. 1 includes a fading speed estimation apparatus 10 and a step constant determiner 11 instead of the memory 9 of FIG.

  The fading speed estimation apparatus 10 estimates the fading speed based on the correlation value of the reception response vector of the signal from the mobile terminal apparatus.

  The reception response vector is calculated by fading speed estimation apparatus 10 as follows. Here, for the sake of explanation, consider a case where a signal from a desired mobile terminal apparatus is received by an array antenna composed of two antennas. The signal from the mobile terminal apparatus is S1 (t), the signal received from the antenna 1 is X1 (t), the signal received from another antenna not shown is X2 (t), and the noise component of the antenna 1 is n1 ( t) Let n2 (t) be the noise component of the other antenna.

The received signal at each antenna at this time is expressed as follows:
X1 (t) = h1S1 (t) + n1 (t)
X2 (t) = h2S1 (t) + n2 (t)
Here, h1 represents a propagation path from a desired mobile terminal apparatus to the antenna 1, and h2 represents a propagation path from the desired mobile terminal apparatus to another antenna, and is a parameter expressed in complex including amplitude and phase. .

At this time, the reception response vector H of the signal S1 (t) is expressed by the following equation:
H = [h1, h2] T (T is transpose)
Here, it is assumed that there is no correlation between S1 (t), n1 (t), and n2 (t).

Further, the signal S1 (t) is generated as the reference signal r1 (t), the received signal X1 (t) is multiplied by the reference signal r1 * (t) (* is a complex conjugate), and an ensemble average is obtained. Calculate h1 (t) based on the following equation:
E [X1 (t) r1 (t)]
= E [X1 (t) S1 (t)]
= E [h1S1 (t) S1 * (t)] + E [n1 (t) S1 * (t)]
= H1E [S1 (t) S1 * (t)] + E [n1 (t) S1 * (t)]
≒ h1
Here, since the ensemble average between the same signals is 1 and the ensemble average between uncorrelated signals is substantially 0, E [S1 (t) S1 * (t)] = 1, E [n1 (t) S1 * (T)] ≈0.

  Similarly, h2 is calculated by multiplying the received signal X2 (t) by the reference signal r1 * (t) and taking an ensemble average. Thereby, the reception response vector H of the signal S1 (t) from the desired mobile terminal device is calculated.

  As described above, fading speed estimation apparatus 10 first calculates a reception response vector of a signal from a mobile terminal apparatus, and further calculates a fading speed based on the calculated reception response vector. The fading speed estimation method will be described below.

  The reception response vector of the signal from the mobile terminal apparatus in a certain frame is H (f), and the reception response vector from the mobile terminal apparatus in the next frame is H (f + 1). As described above, the reception response vector represents a propagation path from the mobile terminal apparatus to the base station. When the fading speed is low, the propagation path changes little, so H (f) and H (f + 1) have similar values, and the correlation value of the reception response vector increases. On the contrary, when the fading speed is high, the propagation path fluctuates greatly, so that H (f) and H (f + 1) have different values, and the correlation value of the reception response vector becomes small.

  Accordingly, a memory (not shown) that stores in advance correlation values between frames of reception response vectors of signals from the mobile terminal apparatus at a plurality of fading rates and stores a correspondence table between the correlation values of the fading rates and the reception response vectors. Is provided in the fading speed estimation apparatus 10. During actual communication, the fading speed estimation device 10 calculates the reception response vector of the signal from the mobile terminal device every frame by the method described above, and obtains the correlation value of the reception response vector between frames. The fading speed of the mobile terminal device can be estimated by referring to the correspondence table with the fading speed described above from the correlation value.

  The step constant determiner 11 determines an optimum step constant according to the fading speed of the mobile terminal apparatus estimated by the fading speed estimation apparatus 10.

  The optimum step constant corresponding to the fading speed is determined as follows. First, the reception level of a signal from a mobile terminal apparatus at a certain fading speed is observed for a predetermined number of frames while changing the step constant, and the reception level is the closest to the target value and the step constant with the least variance is the fading speed. Is the optimal step constant.

  By performing the above procedure for a plurality of fading speeds, a table in which fading speeds correspond to optimum step constants can be created. By storing this correspondence table in a memory or the like (not shown), the step constant determiner 11 can be configured. The step constant read from the step constant determiner 11 is given to the feedback data calculator 7.

  Next, the gain control method according to the first embodiment will be described with reference to FIG. The flowchart shown in FIG. 2 differs from the flowchart shown in FIG. 12 in the following points.

  First, in step S10, a reception response vector is calculated based on a signal from the mobile terminal device.

  In step S11, the fading speed is calculated based on the reception response vector calculated in step S10.

  In step S12, a step constant is determined based on the fading speed calculated in step S11.

  As described above, according to the first embodiment, it is possible to prevent the AGC amplifier 2 from operating nonlinearly due to the influence of fading by determining the step constant according to the fading speed instead of the fixed step constant. it can.

[Embodiment 2]
FIG. 3 is a functional block diagram functionally illustrating a radio apparatus according to the second embodiment of the present invention, and FIG. 4 is a flowchart showing a gain control method according to the second embodiment of the present invention.

  First, referring to FIG. 3, a signal received from antenna 1 is amplified by AGC amplifier 2, converted to an IQ signal by quadrature detector 3, and then stored in memory 4.

  An RSSI detection device 16 that detects received signal strength (hereinafter, RSSI) detects the RSSI of a signal from the mobile terminal device in the antenna 1 in real time.

  The feedback data conversion device 17 obtains feedback data corresponding to the RSSI of the signal from the mobile terminal device detected by the RSSI detection device 16. The feedback data switching device 18 operates to select the output of the feedback data conversion device 17 at the start of reception and to provide it to the gain control input of the AGC amplifier 2. Thereby, the initial value of the AGC gain is set.

  The feedback data converter 17 is configured as follows. The feedback data is changed while keeping the level of the signal from the mobile terminal device constant, and the feedback data is obtained so that the reception level of the signal after passing through the AGC amplifier 2 becomes the target value. Then, by obtaining the corresponding feedback data while changing the level of the signal from the mobile terminal device kept constant, it is possible to create a correspondence table between RSSI and feedback, which is stored in a memory or the like (not shown) By storing the data, the feedback data converter 17 can be configured.

  The reception level detector 12 calculates the reception level based on the IQ signal after passing through the quadrature detector 3. For example, the amplitude of the IQ signal is calculated in the interval of 4 samples after the initial value is set, and the maximum amplitude value is set as the reception level at that moment.

The feedback data calculator 13 calculates feedback data based on the reception level obtained by the reception level detection device 12 and the step constant stored in the memory 15. Here, when the reception level obtained by the reception level detection device 12 is P_max, the predetermined target value is P_ideal, and the step constant is Step, the feedback data at the time of reception of the next frame from the feedback data at the time of reception of the previous frame. The amount of change ΔFB to feedback data can be calculated by:
ΔFB = (P_max−P_ideal) / 2 Step
Therefore, if the feedback data value at the time of receiving the previous frame is FB, the feedback data FB ′ at the time of receiving the next frame can be calculated by the following:
FB ′ = FB−ΔFB
The feedback data calculated by the feedback data calculator 13 is temporarily stored in the memory, and then given to the gain control input of the AGC gain amplifier 2 via the feedback data switching device 18. Since the initial value of the AGC gain of the AGC amplifier 2 is appropriately set, the feedback data is immediately reflected in the AGC.

  Next, a gain control method according to the second embodiment will be described with reference to FIG.

  First, in step S13, the RSSI at the antenna end of the signal from the mobile terminal apparatus is detected.

  In step S14, the RSSI detected in step S13 is converted into feedback data. With reference to the memory storing the correspondence table between the RSSI and the feedback data, the feedback data corresponding to the RSSI detected in step S13 is extracted.

  In step S15, the feedback data obtained in step S14 is immediately reflected in the AGC. That is, the feedback data obtained in step S14 is given to the gain control input of the AGC amplifier 2 as an initial value.

  In step S16, s indicating the sample number at which the amplitude calculation is started is set. That is, in step S16, the number of the sample that detects the burst rising of the signal from the mobile terminal device is set. Here, it is assumed that a burst rising edge is detected at the 40th sample.

  In step S17, j indicates the number of times feedback data is set by detecting the reception level from the mobile terminal device.

  In step S18, if the number of times the feedback data is set by detecting the reception level is 3 or more, the process is terminated, and if not, the process proceeds to the subsequent process.

  In step S19, it is determined whether or not the current sample is a sample period in which the reception level of the signal from the mobile terminal apparatus is detected. For example, when the reception level is detected in an interval of 8 samples from the sample specified by s, if the sample whose amplitude is to be calculated is before the 8th sample from the sample specified by s, The process proceeds to a process for calculating the amplitude of the sample, and otherwise, the process proceeds to a process for calculating feedback data.

  In step S20, the amplitude of the symbol is calculated. A value obtained by squaring the I component of the IQ signal and a value obtained by squaring the Q component are added. Here, in order to simplify the process, the process for obtaining the square root of the added value is not performed.

  In step S21, it is determined whether the amplitude A calculated in step S20 is greater than the maximum amplitude A_max that has been stored so far.

  In step S22, when it is determined in step S21 that A is larger than A_max, A_max is replaced with A.

  In step S23, the sample whose amplitude is calculated is advanced to the next sample.

  In step S24, the change amount of the feedback data is calculated based on the maximum amplitude value and the step constant in the section of 8 samples from the sample specified by s.

  In step S25, feedback data in the next frame is calculated, and the calculated feedback data is immediately reflected in the AGC.

  In step S26, a sample for starting calculation of amplitude is set.

  In step S27, the number of times the feedback data is set is updated.

  As described above, according to the second embodiment, the initial value of the AGC gain is set according to the RSSI at the start of reception, so that the feedback data calculated by the feedback calculator 13 and the feedback data converter 17 can be immediately obtained. It can be reflected in AGC.

[Embodiment 3]
FIG. 5 is a functional block diagram functionally illustrating a radio apparatus according to the third embodiment of the present invention, and FIG. 6 is a flowchart showing a part of the gain control method according to the third embodiment of the present invention. FIG. 7 is a flowchart showing the remaining part of the gain control method according to the third embodiment of the present invention.

  First, referring to FIG. 5, the RSSI detection device 16 detects the RSSI of the signal received by the antenna 1 as described with reference to FIG. 3.

  The feedback data switching device 19 supplies the feedback data read from the feedback data conversion device 17 at the start of reception to the gain control input of the AGC amplifier 2 as an initial value according to the RSSI of the signal from the mobile terminal device, and also at the AGC amplifier 2 The feedback data input to the gain control input is switched from the first gain control feedback device having a low reception level convergence to the second gain control feedback device having a high reception level convergence. For example, switching is performed when the RSSI has decreased by 20 dBμV or more compared to the previous frame, or has increased by 3 dBμV or more.

  The first gain control feedback device basically includes an AGC amplifier 2, a reception level detection device 6, a feedback data calculator 7, a memory 8, and a memory 9, and applies the calculated feedback data to the received value of the next frame. To do. The second gain control feedback device is basically composed of the AGC amplifier 2, the reception level detection device 12, the feedback data calculator 13, the memory 14, and the memory 15, and immediately calculates the calculated feedback data to the currently received frame. To adapt. The difference in convergence speed is due to the difference in step constants stored in the memories 9 and 15.

  Next, a gain control method according to the third embodiment will be described with reference to FIGS.

  In step S28 of FIG. 6, the RSSI frames are compared at the antenna end of the signal from the mobile terminal apparatus detected in step S13. At this time, by storing the RSSI in the reception one frame before, the current RSSI is compared, and if the increase amount is larger than a predetermined threshold A, for example, 5 dBμV, or the decrease amount is a predetermined threshold B, For example, when it is larger than 10 dBμV, gain control (see FIG. 7) at which the reception level converges to the target value is performed at high speed, and otherwise, gain control (see FIG. 7) at which the reception level converges to the target value is performed. 6). The process of FIG. 6 is almost the same as the conventional example of FIG. 12, and the process of FIG. 7 is almost the same as the second embodiment of FIG. Therefore, description of these processes is omitted.

  As described above, according to the third embodiment, the gain convergence speed of AGC can be optimized by switching the feedback data to AGC amplifier 2 in accordance with RSSI.

[Embodiment 4]
FIG. 8 is a functional block diagram functionally illustrating a radio apparatus according to the fourth embodiment of the present invention, and FIG. 9 is a flowchart showing a part of the gain control method according to the fourth embodiment of the present invention. . The radio apparatus shown in FIG. 8 is the same as the radio apparatus according to the third embodiment shown in FIG. 5 except for the following points.

  First, referring to FIG. 8, feedback data switching apparatus 20 determines that a signal from a new mobile terminal apparatus has been received in addition to the initial value setting of feedback data based on RSSI described in the second embodiment. In this case, the first gain control feedback device having a low reception level convergence speed is switched to the second gain control feedback device having a high reception level convergence speed.

  Determination of signal reception from the new mobile terminal apparatus is performed as follows. Feedback data switching device when there is no unique word error or the number of bit errors in the preamble part is equal to or less than a predetermined number of bits as a result of assuming that a signal from a new mobile terminal device has been received and demodulating it 20 determines that a signal from the new mobile terminal apparatus is received, and switches the gain control method.

  Next, a gain control method according to the fourth embodiment will be described with reference to FIGS.

  In step S29 in FIG. 9, demodulation is performed after assuming that a signal from the new mobile terminal apparatus has been received.

  In step S30, when the signal demodulated in step S29 has no unique word error, or when the number of bit errors in the preamble portion is a predetermined threshold value or less, for example, 2 bits or less, the reception level converges to the target value. Gain control (see FIG. 7) is performed at a high speed, and if not, gain control (see FIG. 9) is performed at a low speed at which the reception level converges to the target value. 7 is substantially the same as that of the second embodiment of FIG. 4, and the process of FIG. 9 is substantially the same as the conventional example of FIG. Therefore, description of these processes is omitted.

  As described above, according to the fourth embodiment, the gain convergence speed of AGC can be optimized by switching the gain control method when it is determined that a signal from a new mobile terminal is received.

[Embodiment 5]
FIG. 10 is a functional block diagram functionally illustrating the radio apparatus according to the fifth embodiment of the present invention.

  The reception level detector 24 calculates the reception level based on the amplitude of the RXIF signal before passing through the quadrature detector 3. Other processes are the same as those of the gain control method according to the second embodiment. In the first, third, and fourth embodiments, the reception level can be similarly detected using the RXIF signal, and the same effect as that obtained when the RXIQ signal is used can be obtained.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a functional block diagram functionally explaining the radio apparatus according to the first embodiment of the present invention. It is a flowchart which shows the gain control method by Embodiment 1 of this invention. It is a functional block diagram functionally explaining the radio apparatus according to the second embodiment of the present invention. It is a flowchart which shows the gain control method by Embodiment 2 of this invention. It is a functional block diagram functionally explaining a radio apparatus according to a third embodiment of the present invention. It is a flowchart which shows a part of gain control method by Embodiment 3 of this invention. It is a flowchart which shows a part of gain control method by Embodiment 3 and 4 of this invention. It is a functional block diagram functionally explaining a radio apparatus according to a fourth embodiment of the present invention. It is a flowchart which shows the gain control method by Embodiment 4 of this invention. It is a functional block diagram functionally explaining the radio apparatus according to the fifth embodiment of the present invention. It is a functional block diagram for functionally explaining the conventional radio | wireless apparatus which performs AGC with respect to the signal from a mobile terminal device. FIG. 12 is a flowchart showing a gain control method for optimizing the gain convergence speed of AGC in the conventional radio apparatus shown in FIG. 11.

Explanation of symbols

1 antenna, 2 AGC amplifier, 3 quadrature detector, 4, 8, 9, 14, 15, 23 memory, 5 demodulation circuit, 6, 12, 24 reception level detection device, 7, 13, 25 feedback data calculator, 10 fading Speed estimation device, 11 step constant determination device, 16 RSSI detection device, 17 feedback data conversion device, 18, 19, 20 feedback data switching device, 21 error determination device, 22 demodulator.

Claims (1)

A wireless device that performs automatic gain control on a signal from a terminal device,
Gain control feedback means for performing automatic gain control on the signal according to the level of the signal;
A fading speed estimation means for estimating a fading speed of the end terminal device,
With
The gain control feedback means includes
First gain control means for supplying first feedback data for slowly converging the level of the signal to a target value based on a difference between a change amount of feedback data and past feedback data;
Second gain control means for supplying second feedback data for rapidly converging the level of the signal to a target value based on a correspondence table of received signal strength and feedback data for determining an amplification factor;
A received signal strength detecting means for detecting a received signal strength of the signal from the terminal device in the wireless device;
Further comprising
If the amount of change in the detection result of the reception signal strength detection means is small according to the detection result of the reception signal strength detection means or the estimation result of the fading speed estimation means, the first feedback data is selected and the change Feedback data switching means for selecting the second feedback data when the amount is large ;
Feedback that determines the optimum step constant for determining the gain of the first gain control means according to the fading speed estimated from the estimation result of the fading speed estimation means, and defines the gain of the first gain control means A wireless device comprising feedback data calculation means for calculating data .

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