JP2001251256A - Wireless receiver having received power estimating function and received power estimating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wireless receiver and a received power estimating method with which a received power can be estimated with high accuracy at all times. SOLUTION: A signal received by an antenna 1 is subjected to various ways of signal processing, a GCA 7 with a variable gain amplifies the resulting signal, and an orthogonal demodulator 8 demodulates the amplified signal. A demodulation output level is given to a base band circuit 12, which generates a gain control signal and gives it to a gain control input of the GCA 7 via an exponential amplifier 17. The base band circuit 12 controls the voltage of the gain control signal, so that the demodulation level of the orthogonal demodulator 8 is always constant. Since a nearly linear relation holds between the voltage of the gain control signal generated by the base-band circuit 12 and a received power, the received power corresponding to the voltage of the generated control signal can be estimated with high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio receiver having a reception power estimation function and a reception power estimation method.
In particular, the present invention relates to a radio receiver and a received power estimation method for estimating a power value of a signal wave received from a base station in a terminal of a mobile communication system.

[0002]

2. Description of the Related Art In recent years, a mobile communication system which is rapidly developing, for example, W-CDMA (Wideband-Code Divisi) has been developed.
In the mobile communication system of the Multiple Access (on Multiple Access) system, the power of the signal wave transmitted from the base station according to the reception level of each terminal so that each terminal can always receive the signal wave at an appropriate level. It is configured to adjust the value. For this reason, each terminal needs to measure the reception level of the received signal radio wave, more specifically, the received power value, and send back (feedback) the result as data to the base station.

Conventionally, the received power value of the signal radio wave of such a terminal has not been directly measured, but an automatic gain control (hereinafter referred to as A) for the received signal.
GC) is estimated based on the control signal voltage level.

FIG. 6 is a schematic block diagram showing a configuration of a receiving unit of a conventional terminal having a reception power estimation function in a W-CDMA mobile communication system as an example of a mobile communication system.

Referring to FIG. 6, a signal radio wave arriving from a base station (not shown) is received by antenna 1, and a signal component of a predetermined frequency band is extracted from the received signal by band pass filter (BPF) 2. .

The signal component that has passed through the BPF 2 is amplified via a low noise amplifier (LNA) 3 and provided to a mixer 4. The signal supplied to the mixer 4 is mixed with the RF frequency from the local oscillator (LO-RF) 5 of the RF frequency, frequency-converted, and supplied to the BPF 6.

A signal component passing through the BPF 6 is converted into a gain control amplifier (hereinafter referred to as a GC) of a variable gain.
A) The signal is amplified with a variable gain by 7.

[0008] The output of the GCA 7 is supplied to a quadrature demodulator 8, which outputs a local oscillator (LO-LO) having an IF frequency.
The well-known quadrature demodulation operation is performed in response to the IF frequency from the IF (IF) 9, and the demodulated output is supplied to analog-to-digital converters (ADCs) 10 and 11 to be converted into digital signals. The demodulated outputs converted into digital signals by the ADCs 10 and 11 are input to a baseband circuit (BB) 12.

The baseband circuit 12 is mainly constituted by a digital signal processor (DSP).
-Perform reception processing specific to the CDMA system. As a result, the reproduced analog audio signal is supplied to the speaker 13 and various information is transmitted to the liquid crystal display (LCD) 14.
Displayed above. On the other hand, the user operates the numeric keypad 15 to input various instructions and information to the baseband circuit 12.

The baseband circuit 12 also generates a gain control signal for the GCA 7. That is, the baseband circuit 12 generates a digital gain control signal for controlling the variable gain of the GCA 7 so that the level of the digital demodulation output input from the ADCs 10 and 11 to the baseband circuit 12 is always constant. . This digital gain control signal is converted into an analog gain control signal by the digital / analog converter 16 and applied to the gain control input of the GCA 7.

FIG. 7 shows a circuit diagram of A implemented by the circuit of FIG.
It is a graph which shows the characteristic of GC. More specifically, FIG.
When the input to the baseband circuit 12 is kept constant, the received power of the received radio wave (horizontal axis) and the AGC voltage (vertical axis) which is the voltage value of the gain control signal generated by the baseband circuit 12 are shown. Shows the relationship.

Therefore, if the value (vertical axis) of the AGC voltage generated by the baseband circuit 12 can be known, the received power value (horizontal axis) at that time can be estimated. For example, if the AGC voltage value is high, it is estimated that the reception level (power value) is low. Conversely, if the AGC voltage value is low, it is estimated that the reception level (power value) is high.

If the received power value is estimated based on the correspondence between the received power value and the AGC voltage value in FIG. 7, a signal indicating the value is generated from the baseband circuit 12 and the same terminal is not shown. It is provided to the transmission unit and transmitted to the base station together with other transmission data.

[0014]

As described above, in the reception power estimation operation of the conventional terminal, the reception power value is estimated based on the nonlinear AGC characteristic as shown in FIG.

For this reason, in a region where the received power value is low, A
The change in the GC voltage value is large, and thus the detected AG
Although it was possible to estimate the received power value with considerable accuracy based on the C voltage value, in a region where the received power value is high, A
The change in the GC voltage value is small, and thus the detected AG
The reading error of the received power value based on the C voltage value increases,
There is a problem that the accuracy of estimating the received power value is low.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a radio receiver and a reception power estimating method capable of always estimating the reception power with high accuracy.

[0017]

According to the present invention, there is provided a radio receiver having a reception power estimating function, comprising: a receiving unit, a signal extracting unit, a variable gain amplifying unit, a demodulating unit, a gain controlling unit, It comprises exponential amplification means and reception power estimation means. The receiving means receives the signal radio wave. The signal extracting means extracts a signal from the received signal radio wave. The variable gain control means amplifies the extracted signal with a variable gain. The demodulation means demodulates the signal amplified by the variable gain amplification means. The gain control means generates a gain control signal for controlling the variable gain of the variable gain amplifying means so that the output level of the demodulation means becomes constant. The exponential amplification means amplifies the gain control signal with exponential characteristics. The received power estimating means generates a signal for estimating the power value of the received signal radio wave based on the gain control signal before amplification by the exponential amplifying means.

Preferably, the gain control means and the received power estimation means are digital signal processing means for digitally processing the output level of the demodulation means to generate a gain control signal and a signal for estimating a power value.

More preferably, the digital signal processing means includes means for comparing the output level of the demodulation means with a predetermined range of specified values, and wherein the digital signal processing means includes means for comparing the output level of the demodulation means with the predetermined range of specified values. Means for maintaining the level of the gain control signal and means for increasing or decreasing the level of the gain control signal when the output level of the demodulation means is out of a predetermined range.

More preferably, the digital signal processing means includes a storage means for storing in advance data on a correspondence relationship between the level of the gain control signal and the power value of the signal radio wave, and a storage means for storing the data in accordance with the level of the generated gain control signal. Means for reading a corresponding power value from the data of the corresponding relationship and generating a signal for estimating the power value.

More preferably, the wireless receiver is a W-CD
A terminal in an MA mobile communication system.

According to another aspect of the present invention, a method for estimating the reception power of a wireless receiver includes the steps of receiving a signal radio wave, extracting a signal from the received signal radio wave, and extracting the extracted signal. Amplifying with variable gain;
Demodulating the signal amplified by the variable gain, generating a gain control signal for controlling the variable gain so that the level of the demodulated signal becomes constant, and amplifying the gain control signal by exponential characteristics. And a step of generating a signal for estimating the power value of the received signal radio wave based on the gain control signal before amplification by the exponential characteristic.

Preferably, the step of generating the gain control signal and the step of generating the signal for estimating the power value are performed by digital signal processing of the level of the demodulated signal.

[0024] More preferably, the digital signal processing includes the step of comparing the level of the demodulated signal with a range of a predetermined specified value, and wherein the level of the demodulated signal is within a range of the predetermined specified value. And the step of raising or lowering the level of the gain control signal when the level of the demodulated signal is out of a predetermined range.

More preferably, in the digital signal processing, the data of the correspondence between the level of the gain control signal and the power value of the signal radio wave is stored in advance, and the data is stored in accordance with the level of the generated gain control signal. Reading a corresponding power value from the correspondence data and generating a signal for estimating the power value.

More preferably, the radio receiver is a W-CD
A terminal in an MA mobile communication system.

As described above, according to the present invention, the gain control signal for controlling the variable gain of the variable gain amplifying means is amplified by the exponential amplifying means having an exponential characteristic. The correspondence between the gain control signal and the received power value becomes close to a linear characteristic, so that the reading error of the received power value can be reduced regardless of the magnitude of the gain control signal, and the received power estimation as a whole can be reduced. Accuracy can be improved.

[0028]

Embodiments of the present invention will be described below in detail with reference to the drawings. In the drawings, the same or corresponding portions have the same reference characters allotted, and description thereof will not be repeated.

FIG. 1 is a block diagram of a W system according to an embodiment of the present invention.
FIG. 2 is a schematic block diagram illustrating a configuration of a receiving unit of a terminal having a reception power estimation function in a CDMA mobile communication system. The terminal shown in FIG. 1 is the same as the conventional terminal shown in FIG. 6 except for the following points.

That is, in the conventional terminal shown in FIG.
The analog gain control signal output from C16 is directly G
While provided to the gain control input of CA7, FIG.
In the terminal of the embodiment, the output of the DAC 16 and the GC
An exponential amplifier 17 is provided between the gain control input of A7.

The exponential amplifier 17 is an amplifier having an exponential characteristic which is almost opposite to the AGC characteristic (FIG. 7) of the conventional terminal shown in FIG. 6, and its input / output characteristics are shown in FIG.

As shown in FIG. 2, the exponential amplifier 17 has a small change in its output voltage (that is, the gain control input of the GCA 7) in a region where the AGC voltage value from the DAC 16 which is the input voltage is low, and the AGC voltage value is small. In a high region, the change in the output voltage is large. That is, in a region where the AGC voltage value is low, the AGC
It is necessary to greatly change the voltage.

Therefore, as shown in FIG.
Are connected, in the AGC characteristic diagram of FIG.
Even in a region where the AGC voltage (vertical axis) was low in the past, A
The change in the GC voltage can be increased.

In other words, the insertion of the exponential amplifier 17 makes it possible to provide a nearly linear correspondence between the AGC voltage output from the DAC 16 and the received power value.

FIG. 3 is a functional block diagram of the baseband circuit 12, which is implemented mainly by software using a DSP.

The demodulated outputs from the ADCs 10 and 11 shown in FIG.
2a. The operation of the AGC control unit 12a will be described later in detail.

The digital demodulated output is supplied to the AGC controller 12a.
To the W-CDMA receiving unit 12b. The W-CDMA receiving unit 12b executes various well-known receiving processes (for example, correlation detection using a matched filter, conversion to analog voice by a voice codec, and the like) specific to the W-CDMA system, and reproduces analog data. An audio signal is provided to the speaker 13, and various information is displayed on the LCD 14. On the other hand, the processing of the W-CDMA receiving unit 12b is as follows.
It is controlled by a user's input using the ten keys 15.

In the AGC control unit 12a, the AG
The gain control signal generated by the C control algorithm is
The signal is sent to the exponential amplifier 17 as an analog gain control signal via the DAC 16 and the baseband circuit 12
To the reception level estimating unit 12c. On the other hand, it is assumed that data relating to the correspondence between the AGC voltage and the received power value is stored in the memory 12d in advance. The reception level estimating unit 12c refers to the data in the memory 12d, generates a signal for estimating the received power value, and supplies the signal to a transmitting unit (not shown) in the same terminal.

FIG. 4 shows the baseband circuit 1 shown in FIG.
FIG. 5 is a flowchart showing an AGC control algorithm for generating a gain control signal by an AGC control unit 12a in FIG.

Referring to FIG. 4, it is determined whether or not the input demodulation level provided from quadrature demodulator 8 (FIG. 1) via ADCs 10 and 11 is within a range of a predetermined specified value. Is performed (step S1). As a result, if the input demodulation level is within the range of the specified value, the voltage value (AGC) of the gain control signal output from the AGC control unit 12a
(Voltage value) is kept constant (step S2). on the other hand,
If it is determined that the input demodulation level is not within the specified value range (step S1), it is determined whether the input demodulation level deviates to a higher or lower range than the specified value range. (Step S3).

If it is determined that the input demodulation level deviates to a value higher than the specified value range, control is performed to decrease the AGC voltage value of the generated gain control signal (step S4). . On the other hand, when it is determined that the input demodulation level deviates from the lower range of the specified value, control is performed to increase the AGC voltage value of the generated gain control signal (step S5).

AGC control is performed by the software processing in the AGC control unit 12a such that the input demodulation level from the quadrature demodulator 8 always remains within a specified value range. Moreover, since the exponential amplifier 17 is provided between the DAC 16 and the gain control input of the GCA 7 as described above, the voltage of the gain control signal (AGC voltage value) generated by the AGC control unit 12a and the received power value Has a substantially linear relationship between them, and the received power value is estimated from the AGC voltage value based on this correspondence relationship as described later.

FIG. 5 is a flowchart showing a reception level estimation algorithm of reception level estimating section 12c of baseband circuit 12 for estimating such a reception level, that is, a reception power value.

First, the AGC voltage value of the gain control signal generated by the AGC control section 12a is read (step S1).
1) With reference to the data on the correspondence between the AGC voltage value and the received power value stored in the memory 12d in advance (step S12), the corresponding estimated value of the received power is read from the memory 12d, and The data is transmitted to a transmitting unit (not shown) (step S13).

The data of the estimated value of the received power is transmitted to the base station together with other data via a transmitting unit (not shown), and the power value of the radio wave transmitted from the base station is adjusted according to the estimated value. become.

As described above, according to the embodiment of the present invention, the gain control signal (A
The gain control signal (AGC voltage value) generated in the AGC control unit 12a and the reception power A near linear relationship is established between the values and the values, and the reading error of the corresponding received power value can be reduced over the entire range of the AGC voltage level, thereby improving the accuracy of estimating the received power value as a whole. be able to.

The embodiments disclosed this time are to be considered in all respects as illustrative 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.

[0048]

According to the present invention, in a radio receiver having a reception power estimating function, exponential amplification means for amplifying a gain control signal for controlling the variable gain of the variable gain amplification means with exponential characteristics is provided. And a gain control signal before amplification by exponential amplification means and a received power value can have a nearly linear correspondence, thereby improving the accuracy of estimating the received power value based on the value of the gain control signal. be able to.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram illustrating a configuration of a receiving unit of a terminal according to an embodiment of the present invention.

FIG. 2 is a diagram showing input / output characteristics of the exponential amplifier shown in FIG.

FIG. 3 is a diagram showing a D constituting the baseband circuit shown in FIG.
It is a functional block diagram of SP.

FIG. 4 is a flowchart showing an AGC control algorithm by the DSP shown in FIG. 3;

FIG. 5 is a flowchart showing a reception level estimation algorithm by the DSP shown in FIG. 3;

FIG. 6 is a schematic block diagram illustrating a configuration of a receiving unit of a conventional terminal.

FIG. 7 is a diagram illustrating an AGC characteristic of a receiving unit of the terminal shown in FIG. 6;

[Explanation of symbols]

1 antenna, 2, 6 BPF, 3 LNA, 4 mixer, 5, 9 local oscillator, 7 GCA, 8 quadrature demodulator, 10, 11 ADC, 12 baseband circuit, 1
3 speakers, 14 LCD, 15 numeric keypad, 16
DAC, 17 exponential amplifier.

Claims (10)

[Claims] 1. A radio receiver having a reception power estimating function, comprising: means for receiving a signal radio wave; means for extracting a signal from the received signal radio wave; and amplifying the extracted signal with a variable gain. Variable gain amplifying means; means for demodulating the signal amplified by the variable gain amplifying means; and gain for controlling the variable gain of the variable gain amplifying means such that the output level of the demodulating means is constant. Gain control means for generating a control signal; exponential amplification means for amplifying the gain control signal with exponential characteristics; and a power value of the received signal radio wave based on the gain control signal before amplification by the exponential amplification means. A reception power estimating means for generating a signal to be estimated. 2. The gain control means and the received power estimation means are digital signal processing means for digitally processing an output level of the demodulation means to generate a signal for estimating the gain control signal and the power value. The wireless receiver according to claim 1. 3. The digital signal processing means, comprising: means for comparing the output level of the demodulation means with a predetermined specified range; and when the output level of the demodulation means is within the predetermined specified value range. Means for maintaining the level of the gain control signal, and means for increasing or decreasing the level of the gain control signal when the output level of the demodulation means is outside the range of the predetermined value. 3. The wireless receiver according to 2. 4. The digital signal processing means comprises: storage means for storing in advance data on the correspondence between the level of the gain control signal and the power value of the signal radio wave; and Means for reading a corresponding power value from the stored correspondence data and generating a signal for estimating the power value. 5. The radio receiver according to claim 1, wherein the radio receiver is a terminal in a W-CDMA mobile communication system. 6. A method for estimating received power of a wireless receiver, comprising: receiving a signal radio wave; extracting a signal from the received signal radio wave; and amplifying the extracted signal with a variable gain. Performing the step of: demodulating the signal amplified with the variable gain; generating a gain control signal for controlling the variable gain so that the level of the demodulated signal becomes constant; Amplifying a gain control signal with an exponential characteristic; and generating a signal for estimating a power value of the received signal radio wave based on the gain control signal before amplification by the exponential characteristic. Estimation method. 7. The step of generating the gain control signal and the step of generating a signal for estimating the power value,
The method according to claim 6, wherein the method is performed by performing digital signal processing on the level of the demodulated signal. 8. The digital signal processing, comprising: comparing the level of the demodulated signal with a range of a predetermined specified value; and setting the level of the demodulated signal within the range of the predetermined specified value. Maintaining the level of the gain control signal at a certain time; and increasing or decreasing the level of the gain control signal when the level of the demodulated signal is out of the predetermined range. The received power estimation method according to claim 7, wherein 9. The digital signal processing, wherein data of a correspondence relationship between a level of the gain control signal and a power value of the signal radio wave is stored in advance, and in accordance with a level of the generated gain control signal, Reading the corresponding power value from the stored data of the correspondence and generating a signal for estimating the power value. 10. The method according to claim 6, wherein the radio receiver is a terminal in a W-CDMA mobile communication system.