JP2001267964A - Cdma reception method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a CDMA receiver that can enhance accuracy of pilot signal detection so as to enhance the reception quality. SOLUTION: A residual error is obtained from the mean power of an output of an analog/digital converter 103 and a predetermined reference value. Then, an error correction table 108 is used to obtain a correction coefficient from the residual error. A pilot strength measurement section 107 calculates a pilot strength corrected by the correction coefficient. Thus, even when an AGC circuit 200 does not follow a received signal, the measurement accuracy of the pilot strength can be maintained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a receiving method and apparatus in CDMA mobile communication.

[0002]

2. Description of the Related Art In recent years, the demand for land mobile communications such as automobiles and cellular phones has increased remarkably, and it is important to use frequency effective technology for securing more subscriber capacity in a limited frequency band. It has become to. As one of the multiple access schemes for effective frequency utilization, a code division multiple access (CDMA) scheme has attracted attention. The CDMA system is a multiple access system using a spread spectrum communication technology, and can achieve excellent communication quality due to wideband characteristics, sharp correlation characteristics using codes such as pseudo-random noise (PN) sequences, and the like. A land mobile communication system using the CDMA system is disclosed in, for example, US Pat. No. 4,901,307.

[0003] In the CDMA system, the strength of a neighboring cell can be detected by despreading a pilot channel by changing the phase or type of PN. The mobile station detects the strength and reports the strength to the system control device (mobile communication control station) through the base station so that the handoff can be performed. For example, US Pat. No. 5,267,2 discloses a handoff method in a CDMA mobile communication system.
No. 61 discloses this.

[0004] The operation of a conventional CDMA receiving method and apparatus will be described below with reference to the drawings.

FIG. 4 is a block diagram showing a configuration of a conventional CDMA receiving apparatus. In this figure, the conventional C
The DMA type receiving apparatus includes an antenna 101, a gain control amplification unit 102, an A / D conversion unit 103, an average power calculation unit 104, a residual error calculation unit 105, a control value update unit 106, a pilot strength measurement unit 107 are provided.

[0006] The gain control amplifier 102 amplifies a received signal with a predetermined gain. A / D converter 103
Converts the received signal amplified by the gain control amplifier 102 into a digital signal. The average power calculation unit 104 calculates A /
The average power of the output of the D conversion unit 103 is calculated. The residual error calculator 105 calculates a residual error from the average power and a predetermined reference value. Control value updating section 106 updates the gain of gain control amplification section 102 based on the residual error. Pilot strength measuring section 107 detects a pilot signal included in the received signal, and obtains the strength by despreading the strength.

[0007] Gain control amplification section 102, A / D conversion section 1
03, average power calculator 104, residual error calculator 105
The circuit 200 including the control value update unit 106
The output of the / D converter 103 is controlled to be constant, and is called an AGC circuit (automatic gain control circuit). The pilot strength measuring section 107 detects a pilot signal included in the received signal and obtains a ratio of the strength (PilotEc / Io, PilotEc: chip energy of pilot, Io: received power). A
Assuming that the output of the A / D converter 103 is constant by the GC circuit 200, the pilot strength ratio (PilotEc / Io) can be simply obtained from the power of the despread pilot.

[0008]

However, in the conventional CDMA receiving apparatus, since the AGC circuit 200 cannot completely follow the fluctuation of the received signal (mainly the electrical and processing delay of each circuit), the measurement is not performed. There is a problem that an error occurs in the ratio (Pilot Ec / Io) of the pilot strength to be performed, and this error causes an invalid handoff and a decrease in reception quality.

Further, since there is an error in the correlation value obtained by despreading the output of the AGC circuit 200, the demodulation timing and an invalid path may be selected. In this case, of course, the reception quality is reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a CDMA receiving method and apparatus capable of performing effective handoff even when an AGC circuit does not follow a received signal.

[0011]

According to the CDMA receiving method of the present invention, a power value of a received signal is obtained, an error between the obtained power value and a predetermined reference value is obtained, and the reception is performed based on the obtained error. The gain at the time of amplifying the signal is updated, and the intensity of the pilot signal included in the received signal is corrected by a correction coefficient according to the error.

[0012] Further, the CDMA receiving method of the present invention comprises:
Amplify the received signal with a predetermined gain, digitally convert the amplified received signal to obtain an average power value of the digital output, obtain a residual error from the obtained average power value and a predetermined reference value,
The gain at the time of amplifying the received signal is updated based on the obtained residual error, a correction coefficient corresponding to the residual error is obtained, and the intensity of the pilot signal included in the received signal after the digital output is corrected. .

[0013] The CDMA receiving method of the present invention comprises:
In the CDMA receiving method, the correction coefficient is set to a value obtained by dividing a predetermined reference value A by an average power value B of a digital output, and this value is set to a value obtained by multiplying an original value by B / A. Multiply by

According to these methods, the accuracy of the pilot strength ratio (Pilot Ec / Io) is improved, thereby enabling effective handoff and improving the reception quality.

[0015] The CDMA receiving method of the present invention comprises:
Amplify the received signal with a predetermined gain, digitally convert the amplified received signal to obtain the average power value of the digital output,
Determine the residual error from the determined average power value and a predetermined reference value, update the gain when amplifying the received signal based on the determined residual error, further determine a correction coefficient according to the residual error, The correlation value obtained by despreading the digital output is corrected.

Further, the CDMA receiving method of the present invention comprises:
In the CDMA receiving method, the correction coefficient is set to a value obtained by dividing a predetermined reference value A by an average power value B of a digital output, and this value is multiplied by a despread correlation value multiplied by B / A. I do.

According to these methods, since an accurate correlation value can be obtained, the control of the demodulation timing is accurate, and an effective path can be selected, so that the reception quality is improved.

The CDMA receiver according to the present invention comprises: a gain control amplifier for amplifying a received signal with a predetermined gain; an analog / digital converter for digitally converting the received signal amplified by the gain control amplifier; Average power calculation means for calculating average power from the output of the analog / digital conversion means; residual error calculation means for calculating a residual error from the average power calculated by the average power calculation means and a predetermined reference value; Gain value updating means for updating the gain of the gain control amplification means with the residual error calculated by the error calculating means; correction coefficient generating means for obtaining a correction coefficient from the residual error calculated by the residual error calculating means; From the output of the digital conversion means, the strength of the pilot signal contained in the received signal It adopts a configuration comprising a pilot strength measurement means for obtaining corrected by the correction factor generated from means.

Further, the CDMA receiver according to the present invention comprises:
In the CDMA receiving apparatus, the correction coefficient generation means obtains a correction coefficient by dividing the predetermined reference value A by the average power value B of the digital output.
A configuration is employed in which the correction coefficient A / B is multiplied by the pilot signal strength multiplied by B / A with respect to the original value.

According to these configurations, the gain amplifying means,
A comprising analog / digital conversion means, average power calculation means, residual error calculation means, and gain value update means
Even when the GC circuit cannot completely follow the fluctuation of the received signal, the accuracy of the pilot strength ratio (Pilot Ec / Io) is improved, which enables effective handoff.

Further, the CDMA receiver according to the present invention comprises:
Gain control amplification means for amplifying the received signal with a predetermined gain,
Analog / digital conversion means for digitally converting the received signal amplified by the gain control amplification means, average power calculation means for calculating average power from the output of the analog / digital conversion means, and calculation by the average power calculation means. A residual error calculating means for calculating a residual error from the average power and a predetermined reference value, a gain value updating means for updating a gain of the gain control amplification means with the residual error calculated by the residual error calculating means, A correction coefficient generation means for obtaining a correction coefficient from the residual error calculated by the residual error calculation means, and an output of the analog / digital conversion means is despread using the correction coefficient generated by the correction coefficient generation means. And a correlation detecting means for correcting the correlation value.

Further, the CDMA receiver according to the present invention comprises:
In the CDMA receiver, the correction coefficient generation means obtains a correction coefficient by dividing the predetermined reference value A by the average power value B of the digital output, and the correlation detection means obtains the B / A multiplied despread signal. A configuration is employed in which the correlation value is multiplied by the correction coefficient A / B.

According to these configurations, gain amplifying means,
A comprising analog / digital conversion means, average power calculation means, residual error calculation means, and gain value update means
Even when the GC circuit cannot completely follow the fluctuation of the received signal, an accurate correlation value can be obtained, so that the demodulation timing control becomes accurate and the path selection is improved, thereby improving the reception quality.

A mobile station apparatus according to the present invention employs a configuration including the CDMA receiving apparatus.

The provision of the CDMA receiving apparatus can improve the reception quality.

A base station apparatus according to the present invention employs a configuration including the CDMA receiving apparatus.

The provision of the CDMA receiving apparatus can improve the reception quality.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The gist of the present invention is to correct the output of an AGC circuit with a correction coefficient corresponding to the residual error of the AGC circuit.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1) FIG. 1 is a block diagram showing a configuration of a CDMA receiving apparatus according to Embodiment 1 of the present invention. In this figure, parts common to FIG. 4 described above are denoted by the same reference numerals and description thereof is omitted.

This embodiment has an error correction table (correction coefficient generation means) 108 for obtaining a correction coefficient for correcting the strength of the pilot signal from the residual error output from the residual error calculation section 105. The pilot strength measurement unit 107 corrects the strength of the pilot signal using the correction coefficient obtained from the error correction table 108.

Here, a method of correcting the residual error of AGC circuit 200 in pilot intensity measuring section 107 will be described. The reference value given to the residual error calculation unit 105 is A
Assuming that the output of the average power calculation unit 104 is B, the input of the error correction table 108 is (AB), and the error correction table 108 outputs a correction coefficient A / B. At this time, since the strength of the pilot signal measured by pilot strength measuring section 107 is calculated based on reference value A, it is multiplied by B / A with respect to the original value, and Pilo is multiplied.
t Ec / Io × B / A. The correction coefficient A / B
B / A are offset by multiplying
lot Ec / Io is obtained.

As described above, according to the present embodiment, when determining the strength of a pilot signal included in a received signal,
Since the correction is performed using the correction coefficient corresponding to the residual error of the AGC circuit 200, an accurate pilot strength can be obtained even when the AGC circuit 200 cannot follow the fluctuation of the received signal. As a result, effective handoff can be performed, so that the reception quality can be improved.

(Embodiment 2) FIG. 2 is a block diagram showing a configuration of a CDMA receiving apparatus according to Embodiment 2 of the present invention. In this figure, parts common to FIG. 4 described above are denoted by the same reference numerals and description thereof is omitted.
In the present embodiment, a correlation detection unit 109 for despreading a received signal to detect a correlation value, and a phase tracking unit for generating phase control information for controlling demodulation timing based on the correlation value from the correlation detection unit 109 110 and the correlation detection unit 10 based on the phase control information from the phase tracking unit 110.
A demodulation unit 111 for obtaining demodulated data from the correlation value from No. 9;
have.

The correlation detector 109 detects a correlation value from the output of the AGC circuit 200, and corrects the detected correlation value with a correction coefficient obtained from the error correction table 108. Then, the corrected correlation value is output to phase tracking section 110 and demodulation section 111.

Here, a method for correcting the residual error of the AGC circuit 200 by the correlation detection unit 109 will be described.
As in the description of the first embodiment, the reference value in the residual error calculator 105 is A, and the average power calculator 1
Assuming that the output of 04 is B, a correction coefficient A / B is obtained. At this time, in the correlation detection unit 109, the correlation value obtained by despreading the output of the A / D conversion unit 103 is B / A times. The original correlation value can be obtained by multiplying this by the correction coefficient A / B.

As described above, according to the present embodiment, AG
When detecting the correlation value from the output of the C circuit 200, the AGC
Since the correlation value is corrected using the correction coefficient corresponding to the residual error of the circuit 200, an accurate correlation value can be obtained even when the AGC circuit 200 cannot follow the fluctuation of the received signal. As a result, the control of the demodulation timing becomes accurate, and the reception quality can be improved.

(Embodiment 3) FIG.3 is a block diagram showing a configuration of a CDMA receiving apparatus according to Embodiment 3 of the present invention. 1 and 4 described above in FIG.
The same reference numerals are given to the same parts as those described above, and the description thereof will be omitted. The present embodiment has a path intensity measuring unit 112 for detecting the intensity and phase of a multipath in a received signal.
The path intensity measuring unit 112 detects the intensity and phase of the multipath from the correlation value from the correlation detecting unit 109.

In the present embodiment, similarly to the second embodiment, correlation detection section 109 corrects the correlation value using a correction coefficient corresponding to the residual error of AGC circuit 200. , It is possible to obtain an accurate correlation value even when the variation cannot be tracked. As a result, a more effective path can be selected and demodulated, and the reception quality can be improved.

Note that the CDMA receiving apparatus of the present invention
It goes without saying that it is installed in a cellular type mobile station device or base station device.

[0040]

As described above, according to the present invention,
Even when the AGC circuit does not follow the received signal, effective handoff, accurate demodulation timing control and path selection can be performed, so that the reception quality can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a CDMA receiving apparatus according to Embodiment 1 of the present invention.

FIG. 2 is a block diagram showing a configuration of a CDMA receiving apparatus according to Embodiment 2 of the present invention.

FIG. 3 is a block diagram showing a configuration of a CDMA receiving apparatus according to Embodiment 3 of the present invention.

FIG. 4 is a block diagram showing a configuration of a conventional CDMA receiving apparatus.

[Explanation of symbols]

 Reference Signs List 101 antenna 102 gain control amplification unit 103 A / D conversion unit 104 average power calculation unit 105 residual error calculation unit 106 control value update unit 107 pilot intensity measurement unit 108 error correction table 109 correlation detection unit 110 phase tracking unit 111 demodulation unit 112 path Intensity measuring unit 200 AGC circuit

Claims (11)

[Claims] 1. A power value of a received signal is obtained, an error between the obtained power value and a predetermined reference value is obtained, and a gain for amplifying the received signal is updated based on the obtained error. C. correcting the strength of a pilot signal included in the received signal by a correction coefficient corresponding to an error.
DMA reception method. 2. Amplifying a received signal with a predetermined gain, digitally converting the amplified received signal to obtain an average power value of a digital output, and obtaining a residual error from the obtained average power value and a predetermined reference value. Updating the gain when amplifying the received signal based on the obtained residual error, further obtaining a correction coefficient corresponding to the residual error, and correcting the strength of the pilot signal included in the received signal after the digital output. A CDMA receiving method. 3. A correction coefficient is defined as a value obtained by dividing a predetermined reference value A by an average power value B of a digital output, and this value is calculated based on the pilot signal strength B / A times the original value. 3. The CDM according to claim 2, wherein
A receiving method. 4. Amplifying a received signal with a predetermined gain, digitally converting the amplified received signal to obtain an average power value of a digital output, and obtaining a residual error from the obtained average power value and a predetermined reference value. Updating the gain when amplifying the received signal based on the obtained residual error, further obtaining a correction coefficient according to the residual error, and correcting the correlation value obtained by despreading the digital output. Characteristic CDMA receiving method. 5. The correction coefficient is a value obtained by dividing a predetermined reference value A by an average power value B of a digital output.
5. The CDMA receiving method according to claim 4, wherein the multiplication is performed on the despread correlation value multiplied by / A. 6. A gain control amplifier for amplifying a received signal with a predetermined gain, an analog / digital converter for digitally converting the received signal amplified by the gain control amplifier, and an output of the analog / digital converter. Average power calculation means for calculating more average power, residual error calculation means for calculating a residual error from the average power calculated by the average power calculation means and a predetermined reference value, and calculated by the residual error calculation means. Gain value updating means for updating the gain of the gain control amplification means with the residual error, correction coefficient generating means for obtaining a correction coefficient from the residual error calculated by the residual error calculating means, and output from the analog / digital conversion means. The strength of the pilot signal included in the received signal is supplemented by the correction coefficient generated by the correction coefficient generation means. And a pilot strength measuring means for obtaining a CDMA system. 7. The correction coefficient generating means divides a predetermined reference value A by an average power value B of a digital output to obtain a correction coefficient.
7. The CD according to claim 6, wherein the intensity of the pilot signal multiplied by A is multiplied by the correction coefficient A / B.
MA receiver. 8. A gain control amplifier for amplifying a received signal with a predetermined gain, an analog / digital converter for digitally converting the received signal amplified by the gain control amplifier, and an output of the analog / digital converter. Average power calculation means for calculating more average power, residual error calculation means for calculating a residual error from the average power calculated by the average power calculation means and a predetermined reference value, and calculated by the residual error calculation means. Gain value updating means for updating the gain of the gain control amplification means with a residual error, correction coefficient generating means for obtaining a correction coefficient from the residual error calculated by the residual error calculating means, and correction coefficient generating means. A phase for correcting a correlation value obtained by despreading the output of the analog / digital conversion means using a correction coefficient. And a function detecting means. 9. A correction coefficient generating means for obtaining a correction coefficient by dividing a predetermined reference value A by an average power value B of a digital output, and a correlation detecting means for obtaining a correlation value after despread multiplied by B / A. 9. The CDMA receiving apparatus according to claim 8, wherein the correction coefficient is multiplied by the correction coefficient A / B. 10. A mobile station apparatus comprising the CDMA receiving apparatus according to claim 6. Description: 11. A base station apparatus comprising the CDMA receiving apparatus according to any one of claims 6 to 9.