JP2000134133A - Receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an AGC function from instructing excess amplification to a variable gain amplifier. SOLUTION: A logic OR circuit 109 conducts OR arithmetic operation of positive and negative overflow flags of Ich/Qch reception signals outputted from A/D converters 105, a counter 110 counts and outputs number of samples causing overflow per prescribed time, and a comparator circuit 111 compares the sample number with a preset reference value for their quantities. When the sample number is less than a reference value, an output signal from an averaging circuit 114 is given to an integration circuit 116, or when the sample number is more than the reference value, a 'zero' value is given to the integration circuit 116 respectively. The integration circuit 116 adds an input value to an integrated value at that time, and the sum is used for a control voltage for a variable gain amplifier 103 via a D/A converter 117.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile communication receiver, and more particularly, to a spread spectrum mobile communication receiver.

[0002]

2. Description of the Related Art A conventional spread spectrum mobile communication receiver will be described with reference to FIG. FIG. 5 is a main block diagram showing a schematic configuration of a conventional receiving apparatus for spread spectrum mobile communication.

A received signal captured by a receiving antenna 501 is amplified by a low-noise amplifier 502, and is amplified by a voltage-controlled variable gain amplifier (hereinafter referred to as a variable gain amplifier).
The signal is amplified to an appropriate amplitude by 503 and frequency-converted to a baseband signal by a quasi-synchronous detection circuit 504.

Next, an in-phase component (hereinafter, referred to as Ich) and a quadrature component (hereinafter, referred to as Qch) of the received signal, which are outputs of the quasi-synchronous detection circuit 504, are converted into digital signals by an A / D converter 505, respectively. Further, the correlator 50
6 performs correlation processing with the spreading code used at the time of transmission.

[0005] The output of the correlator 506 is output to the synchronous detection circuit 50.
7, and the error correction code is decoded by an error correction code decoding circuit 508 at the end. Thus, the received data is demodulated.

The output signal of the correlator 506 is subjected to a sum-of-squares operation by a sum-of-squares circuit 509, and a subtraction circuit 510 is provided.
Is subtracted from a preset reference value.
The output of the subtraction circuit 510 is time-averaged by an averaging circuit 511, and is input to an integration circuit 512 including a holding circuit and an adder. The integration circuit 512 adds the output of the averaging circuit 511 to the integration value at that time to generate a new integration value.

The output of the integration circuit 512 is supplied to the D / A converter 5
13, the voltage is converted into an analog voltage, and the
Used as control voltage for By controlling the variable gain amplifier 503, an AGC function for making the output level of the correlator 506 constant is realized.

[0008]

However, the conventional apparatus has the following problems. That is,
If the S / N ratio of the received signal is poor and the AGC function instructs the variable gain amplifier to saturate the A / D converter, the received signal is extremely distorted, and the correlator output power is reduced. Therefore, there is a problem in that a further amplification is instructed to the variable gain amplifier, so that a loop state occurs, the loop cannot be escaped, and a normal device operation cannot be performed.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above circumstances, and has as its object to provide a spread spectrum type mobile communication receiving apparatus which prevents an AGC function from instructing a variable gain amplifier to perform excessive amplification. I do.

[0010]

The gist of the present invention is that an A / D
Monitoring the sampling exceeding the dynamic range in the converter, counting the number of samplings, and maintaining the amplification value of the variable gain amplifier when the count exceeds the reference value.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A receiving apparatus according to a first aspect of the present invention includes a variable gain amplifier capable of adjusting a gain, gain adjusting means for controlling an amplification amount of the variable gain amplifier, and converting a received signal into a digital signal. Monitoring means for monitoring the sampling exceeding the dynamic range in the A / D converter to be converted; and control means for performing control for maintaining the amplification value of the variable gain amplifier at the time when the number of samples exceeds a predetermined value. Is adopted.

According to this configuration, the A / D converter is monitored for overflow and the AGC function is prevented from instructing excessive amplification. Therefore, even if the S / N ratio of the received signal is poor, the A / D conversion is performed. Since the AGC function does not instruct the variable gain amplifier so that the amplifier is saturated, the operation of the device can be stabilized.

[0013] In the receiving apparatus according to a second aspect of the present invention, in the first aspect, the gain adjustment means may include a first arithmetic unit for calculating a sum of squares of an in-phase component and a quadrature component of the received signal; A configuration including a second computing unit that calculates a difference between an output of the first computing unit and a preset reference value and takes an average, and an integrating unit that integrates the output of the second computing unit is adopted.

According to this configuration, the received signal can be amplified according to the reception level of the received signal.

[0015] A receiving apparatus according to a third aspect of the present invention, in the first aspect or the second aspect, employs a configuration in which the monitoring means monitors sampling exceeding an arbitrarily set range.

According to this configuration, it is possible to determine whether or not the input signal voltage is excessive based on an arbitrary threshold value as compared with the case where the overflow is monitored.

According to a fourth aspect of the present invention, there is provided a mobile station apparatus for mobile communication including the receiving apparatus according to any one of the first to third aspects.

According to this configuration, even when the S / N ratio of the received signal is poor, the AGC function operates stably, so that the operation of the device can be stabilized.

A fifth aspect of the present invention is a base station apparatus for communicating with the mobile station apparatus according to the fourth aspect.

According to this configuration, in each device, even when the S / N ratio of the received signal is poor, the AGC function operates stably, so that the device operation can be stabilized.

In a mobile communication receiving method according to a sixth aspect of the present invention, a gain adjusting step of controlling the amount of amplification of a received signal and a dynamic range exceeding a dynamic range during A / D conversion of the received signal into a digital signal are provided. A monitoring step for monitoring sampling and a control step for controlling when the number of samples exceeds a predetermined value to maintain the amplification value of the received signal at that time are provided.

According to this method, the overflow of the A / D converter is monitored to prevent the AGC function from instructing excessive amplification, so that the A / D conversion is performed even when the S / N ratio of the received signal is poor. Since the AGC function does not instruct the variable gain amplifier so that the amplifier is saturated, the operation of the device can be stabilized.

According to a seventh aspect of the present invention, in the mobile communication receiving method according to the sixth aspect, the gain adjusting means calculates a sum of squares of an in-phase component and a quadrature component of the received signal and sets the sum in advance. A calculation step of calculating a difference from the calculated reference value and taking an average, and an integration step of integrating outputs of the calculation step are provided.

According to this method, the reception signal can be amplified according to the reception level of the reception signal.

[0025] In a mobile communication receiving method according to an eighth aspect of the present invention, in the sixth aspect or the seventh aspect, the monitoring means may monitor sampling exceeding an arbitrarily set range. did.

According to this method, it is possible to determine whether or not the input signal voltage is excessive based on an arbitrary threshold value as compared with the case where the overflow is monitored.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In any of the following embodiments, it is assumed that the received signal is a signal that has been QPSK-modulated and transmitted.

(Embodiment 1) A receiver for spread spectrum mobile communication according to Embodiment 1 of the present invention will be described with reference to FIG. FIG. 1 is a main block diagram showing a schematic configuration of a receiving apparatus for spread spectrum mobile communication according to the present embodiment.

The receiving antenna 101 is an antenna for receiving a signal, and the low noise amplifier 102 is an amplifier for obtaining a sufficient noise figure. The variable gain amplifier 103
This is an amplifier whose amplification is controlled so that an appropriate gain can be obtained according to the reception level.

The quasi-synchronous detection circuit 104 includes a transmitter and a multiplier, and divides a received signal into Ich and Qch. A /
The D converter 105 performs A / D conversion on each of Ich and Qch. The correlator 106 performs despreading processing on each of Ich and Qch. The synchronous detection circuit 107 performs synchronous detection from the despread Ich and Qch. The error correction code decoding circuit 108 performs an error correction process.

The logical OR circuit 109 is an arithmetic circuit for calculating a logical sum, and the counter 110 resets an input signal at regular intervals. The comparison circuit 111 determines the magnitude of the input value and the reference value.

The sum of squares circuit 112 is an arithmetic circuit for squaring two input signals and then adding the squared signals. The subtraction circuit 113 is an arithmetic circuit for performing subtraction processing on the two input signals. The averaging circuit 114 performs an averaging process on the input signal.

The switch 115 is a switch controlled by the comparison circuit 111, and the integration circuit 116 includes a holding circuit and an adder, and performs an integration process. D / A converter 1
17 performs D / A conversion of the input signal.

Next, the operation of the receiving apparatus according to the present embodiment having the above configuration will be described.

The received signal captured by the receiving antenna 101 is amplified by a low noise amplifier 102, amplified to an appropriate amplitude by a variable gain amplifier 103, and frequency-converted by a quasi-synchronous detection circuit 104 to a baseband signal.

Next, the Ich and Qch output from the quasi-synchronous detection circuit 104 are converted into digital signals by an A / D converter 105 and further correlated with a spread code used at the time of transmission by a correlator 106. It is processed.

The output of the correlator 106 is supplied to the synchronous detection circuit 10
7, synchronous detection is performed, and finally the error correction code is decoded by the error correction code decoding circuit 108 to demodulate the received data.

On the other hand, the control voltage of the variable gain amplifier 103 is generated as follows.

The logical OR circuit 109 includes the A / D converter 10
5 performs a logical OR operation on the overflow flags on the positive side and the negative side of each of Ich and Qch which are output. The output of the logical OR circuit 109 is input to the enable terminal of the counter 110. Since the counter 110 is reset every predetermined time (for example, every several tens to several hundred samples), the counter 110 outputs the number of samples that have overflowed per certain time.

On the other hand, the output signal of the correlator 106 is subjected to a sum-of-squares operation by a sum-of-squares circuit 112,
In step 3, a subtraction process from a preset reference value is performed. The output of the subtraction circuit 113 is time-averaged by the averaging circuit 114.

The number of samples exceeding the dynamic range per fixed time (hereinafter referred to as the number of overflow samples), which is the output of the counter 110, is input to the comparison circuit 111, and is compared with a preset reference value.

When the calculated overflow sample number is smaller than the reference value, the comparison circuit 111 switches the switch 115 so that the output signal of the averaging circuit 114 is input to the integration circuit 116. The integrating circuit 116 generates a new integrated value by adding the output of the averaging circuit 114 to the integrated value at that time. The output of the integration circuit 116 is converted into an analog voltage by the D / A converter 117 and used as a control voltage of the variable gain amplifier 103.

If the calculated number of overflow samples is larger than the reference value, it means that the voltage value of the input signal to the A / D converter 105 is in an excessive state. The switch 115 is switched so that the set zero value, that is, zero, is input to the integration circuit 116, the operation of the integration circuit 116 is held, and the same control voltage value is variable from the integration circuit 116 via the D / A converter 117. The signal is input to the gain amplifier 103.

As described above, the gain is calculated from the correlation value output and the number of samples of the overflow flag is monitored to prevent the amplification of the variable gain amplifier from becoming excessive, thereby saturating the A / D converter. Thus, it is possible to prevent the received signal from being extremely distorted, the output power of the correlator being conversely reduced, and the gain being controlled to be increased, thereby preventing the AGC loop operation from falling out.
Therefore, the output power of the correlator 106 is maintained at a constant level even in a situation where the S / N ratio of the received signal is poor such that the monotonous increase between the gain of the variable gain amplifier and the correlator output power is lost. Stable AGC can be performed.

When the DC balance of the received signal is good, the overflow flag may use only the positive side or only the negative side of the signal.

Further, when the orthogonal modulation pattern of the received signal is random, a configuration using only the Ich or the Qch as the overflow flag is also possible.

(Second Embodiment) A spread spectrum mobile communication receiving apparatus according to a second embodiment of the present invention has the same configuration as that of the spread spectrum mobile communication receiving apparatus according to the first embodiment. However, the A / D converter outputs a reference value excess flag instead of the overflow flag.

Hereinafter, the receiving apparatus for spread spectrum mobile communication according to the present embodiment will be described with reference to FIG. FIG. 2 is a main block diagram showing a schematic configuration of a receiving apparatus for spread spectrum mobile communication according to Embodiment 2 of the present invention. Note that the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description is omitted.

The A / D converter 201 is, for example, a parallel A / D converter.
A D / D converter, using an output of an appropriate comparator inside the A / D converter, and setting a reference value excess flag indicating that an input signal voltage to the A / D converter 201 has exceeded a predetermined level. Generates both positive and negative sides.

The logical OR circuit 109 includes the A / D converter 20
The logical sum of the reference value excess flags on the positive and negative sides of each of Ich and Qch output by 1 is calculated. Hereinafter, the procedure for performing AGC is the same as in the first embodiment.

As described above, in this embodiment, an arbitrary range can be set instead of the dynamic range, and the overflow can be monitored based on this range. Therefore, by monitoring the number of samples of the reference value excess flag to prevent the amplification of the variable gain amplifier from becoming excessive, the received signal becomes extremely distorted due to the saturation of the A / D converter, and the correlator output power is reduced. Can be prevented from becoming incapable of exiting from the AGC loop operation in which the control is increased and the gain is increased. Therefore, the S of the received signal such that the monotonous increase between the gain of the variable gain amplifier and the output power of the correlator breaks down.
Even in a situation where the / N ratio is poor, the output power of the correlator 106 can be maintained at a constant level, and stable AGC can be performed.

When the DC balance of the received signal is good, the reference value excess flag may be configured to use only the positive side or only the negative side of the signal.

When the orthogonal modulation pattern of the received signal is random, the reference value excess flag may use only Ich or only Qch.

(Embodiment 3) A spread spectrum mobile communication receiving apparatus according to Embodiment 3 of the present invention has the same configuration as that of the spread spectrum mobile communication receiving apparatus according to Embodiment 1. However, the control voltage of the variable gain amplifier is generated using the overflow flag.

The receiving apparatus for spread spectrum mobile communication according to the present embodiment will be described below with reference to FIG. FIG. 3 is a main block diagram showing a schematic configuration of a receiving apparatus for spread spectrum mobile communication according to Embodiment 3 of the present invention. Note that the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description is omitted.

The logical OR circuit 109 is connected to the A / D converter 10
5 performs a logical OR operation on the positive and negative over flags of the respective Ich and Qch output by Logical OR circuit 109
Is input to the enable terminal of the counter 110. The counter 110 is reset every predetermined time (for example, every several tens to several hundreds of samples).
Outputs the number of samples that have overflowed per fixed time.

Next, the subtractor 301 calculates a difference between the calculated number of overflow samples and a preset reference value. The result of this operation is time-averaged by the averaging circuit 114 and input to the integration circuit 116. The integrating circuit 116 generates a new integrated value by adding the output of the averaging circuit 114 to the integrated value at that time. Integration circuit 11
The output of No. 6 is converted into an analog voltage by the D / A converter 117 and used as a control voltage of the variable gain amplifier 103.

As described above, the gain is calculated from the counter output, the number of samples overflowing within a predetermined time is counted, and the variable gain amplifier 103 is controlled so that the number of samples counted within this fixed time becomes constant. By controlling the gain, AGC can be performed with a small amount of calculation. Therefore, since the AGC function can be realized without using a square sum circuit or an analog level detection circuit, the device can be simplified and reduced in cost.

When the DC balance of the received signal is good, the overflow flag may be configured to use only the positive side or only the negative side of the signal.

When the orthogonal modulation pattern of the received signal is random, the overflow flag may use only Ich or only Qch.

(Embodiment 4) A spread spectrum mobile communication receiving apparatus according to Embodiment 4 of the present invention has the same configuration as that of the spread spectrum mobile communication receiving apparatus according to Embodiment 3. However, the A / D converter outputs a reference value excess flag instead of the overflow flag.

Hereinafter, the receiving apparatus for spread spectrum mobile communication according to the present embodiment will be described with reference to FIG. FIG. 4 is a main block diagram showing a schematic configuration of a receiving apparatus for spread spectrum mobile communication according to Embodiment 4 of the present invention. Note that the same components as those of the third embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

The A / D converter 401 is, for example, a parallel type A / D converter.
A D / D converter, using an output of an appropriate comparator inside the A / D converter, and setting a reference value excess flag indicating that the input signal voltage to the A / D converter 401 has exceeded a predetermined level. Generates both positive and negative sides.

The logical OR circuit 109 includes the A / D converter 40
The logical sum of the reference value excess flags on the positive and negative sides of each of Ich and Qch output by 1 is calculated. Hereinafter, the procedure for performing AGC is the same as in the third embodiment.

As described above, the number of samples exceeding a predetermined level is counted within a predetermined time, and the gain of the variable gain amplifier 103 is controlled so that the number of samples counted within this predetermined time becomes constant. By doing so, AGC can be performed with a small amount of computation. Therefore, since the AGC function can be realized without using a square sum circuit or an analog level detection circuit, the device can be simplified and reduced in cost.

When the DC balance of the received signal is good, the reference value excess flag may be configured to use only the positive side or the negative side of the signal.

When the orthogonal modulation pattern of the received signal is random, the reference value excess flag may be configured to use only Ich or only Qch.

In the first to fourth embodiments, the case where the received signal is a signal transmitted by QPSK modulation has been described. However, the processing on the receiving side is performed with the in-phase component (Ich)
The present invention can be applied to any configuration using orthogonal components (Qch).

[0069]

As described above, according to the present invention,
It is possible to prevent the AGC function from instructing the variable gain amplifier to perform excessive amplification.

[Brief description of the drawings]

FIG. 1 is a main block diagram showing a schematic configuration of a receiving apparatus for spread spectrum mobile communication according to Embodiment 1 of the present invention.

FIG. 2 is a main block diagram showing a schematic configuration of a receiver for spread spectrum mobile communication according to Embodiment 2 of the present invention;

FIG. 3 is a main block diagram showing a schematic configuration of a receiving apparatus for spread spectrum mobile communication according to Embodiment 3 of the present invention;

FIG. 4 is a main block diagram showing a schematic configuration of a receiving apparatus for spread spectrum mobile communication according to Embodiment 4 of the present invention.

FIG. 5 is a main block diagram showing a schematic configuration of a conventional spread spectrum mobile communication receiving apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 101 Receiving antenna 102 Low noise amplifier 103 Voltage control variable gain amplifier (variable gain amplifier) 104 Quasi-synchronous detection circuit 105 A / D converter 106 Correlator 107 Synchronous detection circuit 108 Error correction code decoding circuit 109 Logical OR circuit 110 Counter 111 Comparison Circuit 112 Sum of squares circuit 113 Subtraction circuit 114 Averaging circuit 115 Switch 116 Integrator circuit 117 D / A converter 201 A / D converter 301 Subtractor 401 A / D converter

Continued on front page F term (reference) 5J100 AA03 AA16 AA22 BA01 CA23 CA27 CA28 CA29 CA32 CA33 DA06 EA02 FA02 MA01 QA01 SA02 5K004 AA05 FA05 FG04 FH04 5K022 EE01 EE31 5K061 AA05 BB12 CC52

Claims (8)

[Claims] 1. A gain controllable variable gain amplifier, gain adjustment means for controlling an amplification amount of the variable gain amplifier, and monitoring of sampling exceeding a dynamic range in an A / D converter for converting a received signal into a digital signal. And a control means for controlling when the sampling number exceeds a predetermined value to maintain the amplification value of the variable gain amplifier at that time. 2. The gain adjusting means according to claim 1, wherein said first arithmetic unit calculates a sum of squares of an in-phase component and a quadrature component of a received signal, and calculates a difference between an output of said first arithmetic unit and a preset reference value. The receiving device according to claim 1, further comprising: a second calculating unit that calculates and averages the data, and an integrating unit that integrates an output of the second calculating unit. 3. The receiving apparatus according to claim 1, wherein said monitoring means monitors sampling exceeding an arbitrarily set range. 4. A mobile station device for mobile communication, comprising the receiving device according to claim 1. 5. A base station apparatus for communicating with the mobile station apparatus according to claim 4. 6. A gain adjusting step of controlling the amount of amplification of a received signal, a monitoring step of monitoring sampling exceeding a dynamic range during A / D conversion of the received signal into a digital signal, and a step of monitoring the sampling number to a predetermined value. A control step of performing control to maintain the amplification value of the received signal at the time when the signal has exceeded the threshold value. 7. The gain adjusting means calculates a sum of squares of the in-phase component and the quadrature component of the received signal, calculates a difference between the reference value and a preset reference value, and calculates an average. 7. A receiving method for mobile communication according to claim 6, further comprising an integrating step of integrating the outputs of the mobile communication. 8. The mobile communication receiving method according to claim 6, wherein said monitoring means monitors sampling exceeding an arbitrarily set range.