JPH1155169A - Maximum ratio synthesizing method and diversity receiver using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify a circuit scale for a maximum ratio synthesizing method for synthesizing the received signals of plural branches and a diversity receiver using this maximum ratio synthesizing method. SOLUTION: The gains of AGC amplifiers 16A and 16B corresponding to the branch of a diversity system are controlled by AGC parts 20A and 20B, and the gains between the branches are corrected and synthesized by a synthesizing part 21. For such a maximum ratio synthesizing method and the diversity receiver using the same method, based on gain control signals from the AGC parts 20A and 20B, a gain control circuit 12 controls the AGC amplification gain of the other branch to the power of '2'-fold of a reference gain with the AGC amplification gain of one branch as the reference gain. Then, bits corresponding to bit shift are selected by selectors 19A and 19B corresponding to the power of '2'-fold so that the branches are synthesized by the synthesizing part 21, while correcting their gains.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a maximum ratio combining method for combining received signals of a plurality of branches and a diversity receiver using the maximum ratio combining method. 2. Description of the Related Art In a wireless communication system, a diversity system that enables stable transmission / reception even with a change in a propagation state of a radio wave is relatively frequently employed. In this diversity system, as a method of combining received signals corresponding to branches, a selection combining method of selecting a received signal having a larger amplitude, an equal gain combining method of performing equal weighting on received signals and combining the same,
There is known a maximum ratio combining method in which weighting is performed in proportion to a received signal amplitude and combining is performed. Among these combining methods, the maximum ratio combining method has an advantage that the signal-to-noise power ratio is the largest.

[0002]

2. Description of the Related Art FIG.
Is an antenna, 52 is a duplexer, 53 is a transmitter, 54 is a transmission signal processor, 55 is a receiver, 56 is an AGC amplifier,
57 is a demodulator, 58 is a despreader, 59 is a gain corrector, 6
0 indicates an AGC unit, 61 indicates a synthesis processing unit, 62 indicates a reception signal processing unit, 63 indicates a reception output unit, and indicates one CDM of a modulation method.
The main part when the A (Code Division Multiple Access) method is applied is shown.

In a transmission system of a mobile unit in a wireless communication system, a transmission signal processing unit 54 processes a voice signal from a microphone or input data from a keyboard or the like, and a transmission unit 53 performs spread modulation, QAM, and the like. , And performs a quadrature modulation, a frequency conversion, a high frequency amplification, and the like, and transmits the signal from the antenna 51 via the duplexer 52.

The receiving system of the mobile unit receives a signal received by an antenna 51 by a receiving unit 55 via a duplexer 52, performs high-frequency amplification, frequency conversion, intermediate frequency amplification, etc., and performs an AGC amplifier 56 and a demodulation unit. 57, a despreading unit 58, and a gain correction unit 59, and input to the synthesis processing unit 61,
The gain of the AGC amplifier 56 is controlled by the unit 60, and the gain of the received signal by the gain control is corrected by the gain correction unit 59 with the opposite characteristic, and the branch processing by the diversity system is performed by the synthesis processing unit 61. CDM
A received signal corresponding to the finger according to the A system is synthesized, a process corresponding to the audio signal or the data is performed in the reception processing unit 62, and the audio signal is reproduced and output by the speaker in the reception output unit 63, and the data is output. Output to the display.

FIG. 8 is an explanatory view of a main part of a conventional receiving system, showing a case where a diversity system, a CDMA system, and a RAKE system are combined.
5A and 55B are receivers, 56A and 56B are AGC amplifiers, 57A and 57B are demodulators, 58A and 58B are despreaders, 59A and 59B are multipliers, and 60A and 60B are AGCs.
, 61 indicates a combining unit, and 64A and 64B indicate reciprocal parts.

The basic configuration and operation are the same as those of the receiving system shown in FIG. 7. The signals received by the antennas 51A and 51B are subjected to high-frequency amplification, frequency conversion and intermediate frequency amplification by the receiving units 55A and 55B. AGC amplifier 56A, 5
6B. The AGC units 60A and 60B correspond to the AGC amplifiers 56A and 60B in response to the diversity branch.
AGC amplifiers for controlling the gains of A and 56B, performing despreading demodulation by despreading units 58A and 58B corresponding to the multipath in each branch, and adjusting the gain between branches to perform maximum ratio combining. The reciprocals of the gain control signals of 56A and 56B are obtained in reciprocal parts 64A and 64B, and are multiplied in multipliers 59A and 59B. That is, in the branch where the input signal level is low, the gain of the AGC amplifier is controlled to increase, and in the multipliers 59A and 59B, the gain control signal of the gain control signal is reduced so as to reduce the level by the increased gain. Multiply the reciprocal. The combining unit 61 performs RAKE combining for combining signals corresponding to a plurality of fingers, performs maximum ratio combining of signals corresponding to branches, and outputs the result as a received signal.

[0007]

A mobile station in a wireless communication system is required to be small and lightweight. Therefore, it is desirable to reduce the circuit scale. However, as described above, when performing the maximum ratio combining by applying the diversity system, the conventional mobile station needs to keep the noise level before combining constant, and performs AGC independently for each branch. Therefore, it is necessary to correct the gain corresponding to the branch. This gain correction is performed by the multiplier 59
A, 59B, but there is a problem that the circuit size of the multiplier becomes large even in the case of digital processing. Also, for synchronous detection in the CDMA system, a method is known in which a reference phase is determined from a known signal such as a pilot signal, and the reference phase is performed using the signal. However, only the phase component of the pilot signal is detected and used, and other components of the pilot signal are not effectively used. An object of the present invention is to effectively use a pilot signal and reduce the circuit scale.

[0008]

SUMMARY OF THE INVENTION The maximum ratio combining method of the present invention is as follows: (1) In a wireless communication system, a reference signal such as a pilot signal including an amplitude component and a phase component corresponding to a finger or a branch from a received signal. , And the reference signal is multiplied by the finger-corresponding or branch-corresponding reception signal to perform synchronous detection, and a synchronous detection output signal having an amplitude corresponding to the amplitude component of the pilot signal is added, thereby synthesizing between fingers or between branches. And synchronous detection and maximum ratio combining can be performed using the phase component and the amplitude component of the pilot signal.

(2) A maximum ratio combining method for combining with weights proportional to received signal amplitudes corresponding to a plurality of branches in a wireless communication system, wherein a gain of AGC amplification of any one of the plurality of branches is provided. In this case, the gain of the AGC amplification of the other branch is set to the power of 2, and the gain correction for the branch of the gain of the power of 2 is performed by bit shifting to combine the branches. Accordingly, the gain of a signal having a plurality of bits can be corrected by a bit shift by a selector without using a multiplier.

(3) The gain of the branch with the smallest AGC amplification gain among the plurality of branches is set as the reference gain, the gain of the other branches is set to a power of 2 times the reference gain, and the gain between the branches is corrected. The method may include a step of performing a bit shift corresponding to a gain of a power of two.

(4) The gain in the branch having the smallest AGC amplification gain at the head position of each frame in the frame of the received signal is used as the reference gain, and the AG of the other branch is used as the reference gain.
The gain of C amplification is set to a power of 2 of the reference gain, and the gain variation in the frame is controlled to be a power of 2 of the reference gain. As a reference, the method may include a step of performing a bit shift corresponding to a gain of a power of 2 with respect to another branch.

(5) AGC with respect to the head of the frame of the received signal in a specific branch of the plurality of branches
The method may include the step of setting the gain of amplification as a reference gain and setting the gain of AGC amplification of another branch to a power of 2 with respect to the reference gain.

(6) The gain of AGC amplification corresponding to a plurality of branches is approximated to a power-of-two ratio between branches.
A bit shift corresponding to the power of 2 may include a process of performing gain correction between branches.

Further, the diversity receiving apparatus of the present invention comprises:
(7) An extracting unit for extracting a reference signal such as a pilot signal including an amplitude component and a phase component corresponding to a finger or a branch from a received signal, and a complex conjugate unit for calculating a complex conjugate number of the reference signal extracted by the extracting unit. A synchronous detector for performing synchronous detection by multiplying the output signal of the complex conjugate by the received signal and synthesizing the synchronous detection output signal of the synchronous detector to obtain an output signal corresponding to the maximum ratio combination. Section.

(8) an AGC amplifier corresponding to a branch;
A plurality of AGC sections corresponding to the branch for controlling the gain of the AGC amplifier, a selector corresponding to the branch for performing gain correction for maximum ratio combining by bit shifting, and a gain control signal by the AGC section corresponding to the branch are provided. The AGC amplifier of one of the branches is controlled by the reference gain, the AGC amplifier of the other branch is controlled by the power of 2 times the reference gain, and the gain of the AGC amplifier is controlled. A gain control circuit that controls the amount of bit shift of the selector for performing gain correction, and a combining unit that combines the output signals of the selectors at a maximum ratio, so that gain correction can be performed without using a multiplier. it can.

(9) The AGC section includes a comparator for comparing the reference value with the signal power, a counter for averaging the output signal of the comparator, and a gain control signal of the AGC amplifier from the gain control circuit. A reference value generator that outputs the reference value based on the output signal of the counter.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory diagram of a main part of a first embodiment of the present invention, and shows a receiving system RAK for performing maximum ratio combining.
The main part corresponding to a finger in the E system or a branch in the diversity system is shown. In FIG.
1-1 to 1-m are extraction units for extracting amplitude and phase components from pilot signals, 2-1 to 2-m are complex conjugate units, and 3-1 to 1-m.
3-m is a synchronous detection unit, 4-1 to 4-m are despreading processing units,
Reference numerals 5-1 to 5-m denote switches that are turned on when a pilot signal is received, and reference numeral 6 denotes a combining unit.

The despreading processing units 4-1 to 4-m include, for example,
Including a sliding correlator, a despreading code generator, and a despreading demodulator, receiving the CDMA signal by inputting the despreading code to the despreading demodulator while synchronizing the despreading code generator so that the correlation is maximized. Are despread demodulated, and when the head of the pilot signal is detected, switches 5-1 to 5
-M is turned on, and the pilot signal is extracted from the extraction units 1-1 to 1-1.
1-m, and the phase component of the amplitude component is extracted.

For example, in each of the extraction units 1-1 to 1-m, A1 + jB1, A2 + jB2,... Are used as amplitude and phase components of the I-axis component and the Q-axis component of the pilot signal.
..Assuming that Am + jBm is output, complex conjugate unit 2
In 1-2 m, A1-jB1, A2-jB2,.
.. A signal having a complex conjugate number of Am-jBmA is output and input to the synchronous detectors 3-1 to 3-m. Synchronous detector 3-1
3-m multiplies the signals of complex conjugate numbers in the synchronous detectors 3-1 to 3-m, performs synchronous detection according to the phase component, and sets the demodulated output signal amplitude according to the amplitude component. Then, the detection output signals of the synchronous detectors 3-1 to 3-m are combined and output in the combiner 6.

In this case, since the state of the propagation path of the received signal corresponding to the finger or the branch is indicated by the pilot signal, the amplitude component of the pilot signal is multiplied by the received signal corresponding to the finger or the branch. By combining, maximum ratio combining has been performed. That is, by using not only the phase component of the pilot signal but also the amplitude component, the configuration can be simplified and an output signal of maximum ratio combining can be obtained. It is also possible to use another reference signal having a known phase similar to the pilot signal.

FIG. 2 is an explanatory diagram of a second embodiment of the present invention, and shows a main part of a diversity receiving apparatus in which a diversity system, a CDMA system, and a RAKE system are combined. In the figure, 11A and 11B are antennas, 12 is a gain control circuit, 15A and 15B are receivers, and 16A and 16B are A.
GC amplifier, 17A, 17B are demodulation units, 18A, 18B
Is a despreading unit, 19A and 19B are selectors, 20A and 20
B is an AGC unit and 21 is a combining unit.

In this embodiment, antennas 11A and 11B, receivers 15A and 15B,
A branch including AGC amplifiers 16A and 16B and demodulation units 17A and 17B is provided, and despreading units 18A and 18B that perform despreading demodulation using a despreading code as a CDMA system.
And a plurality of fingers each including a plurality of despreading units 18A and 18B and selectors 19A and 19B as a RAKE method, and a synthesizing unit 21 outputs signals between fingers and between branches by maximum ratio synthesis. It is.

The selectors 19A and 19B constitute a gain correction section for maximum ratio combining, and are despread sections 18A and 1B.
In 8B, gain correction between branches is performed by bit selection similar to bit shift according to the power of 2 of the amplitude of the despread demodulated signal. Hereinafter, this bit selection will be described as a bit shift. For example, the gain of the AGC amplifier 16A as 2 ^3, in case of a 2 ³ times the amplitude of the received signal, by performing 3-bit backward shift In selector 19A, the amplitude of the despread demodulation signal 1 /
It is possible to to 2 ^3. In this case, the gain of the AGC amplifier in one branch is controlled by the gain control circuit 12 so as to be a power of 2 of the gain of the AGC amplifier in the other branch. , 19B.

For example, assuming that the gain of the AGC amplifier in one branch is performed by the AGC unit and the gain control circuit 12 as usual and the gain B of the AGC amplifier in the other branch is A, the gain to be controlled is A: 2 {(int) [log ₂ (A) +0.5]} (1) Note that “2 ＾” represents a power of 2, and “(int)” represents truncation in the following []. The reason why 0.5 is added is to round off decimal places by rounding.

The gain control circuit 12 includes, for example, the AGC unit 2
0A, the gain control signal of the AGC amplifier 16A,
Based on the gain control signal of the AGC amplifier 16B by the C unit 20B, if the gain A of the AGC amplifier 16A is the gain to be controlled, the gain B of the AGC amplifier 16B is
In accordance with the equation (1), the power is calculated to be a power of two, and AG
The gain of the C amplifiers 16A and 16B is controlled.

The bit shift in the selector 19A is set to zero, and the bit shift in the selector 19B is performed in the reverse direction to correct the gain between branches.
By combining at 1, the maximum ratio combining can be performed. Alternatively, the bit shift by the selector 19B is set to zero, and the bit shift by the selector 19A is
By shifting the number of bits corresponding to the power of 2 in equation (1) and performing gain correction between branches, and combining them in the combining unit 21, maximum ratio combining can be performed.
Therefore, the gain correction between branches is compared with a configuration in which a reciprocal of a gain is obtained and multiplied by a multiplier as in the conventional example. Since this is performed by bit shifting (bit selection) of the signal, the configuration and the processing for maximum ratio combining can be simplified.

The gain control circuit 12 compares the gain control signals of the AGC amplifiers corresponding to a plurality of branches, and uses the gain of the AGC amplifier of the branch with the minimum gain as the reference gain and the gain of the AGC amplifiers of the other branches as the reference gain. It can be controlled so as to be a power of 2 times the gain. In this case, the bit shift by the selector corresponding to the branch of the reference gain is set to zero, and the bit shift by the selector corresponding to the other branch is performed in the reverse direction according to the power of 2 of the reference gain of the AGC amplifier. The gain can be easily corrected during the operation.

Also, when the transmitting side performs convolutional coding and transmits, soft-decisions the output signal of the combining section 21 on the receiving side, and performs maximum likelihood decoding by Viterbi decoding or the like, when transmission is performed by a transmission path such as fading or thermal noise. A signal having an amplitude fluctuation is softly determined. Therefore, the output signal of the synthesizing unit 21 also needs to have an amplitude corresponding to the amplitude fluctuation due to the transmission path. Therefore, when convolutional coding is performed on a frame basis, gain control of the AGC amplifier corresponding to amplitude fluctuation in a frame is performed, and gain correction between branches is performed.

For this purpose, the gain control circuit 12 identifies and compares the gain control signal at the frame start position from the AGC unit corresponding to the branch, sets the gain of the branch with the minimum gain as the reference gain, and sets the AGC of the other branch as the reference gain. The gain of the amplifier is set to a power of 2 of the reference gain, the gain of the AGC amplifier corresponding to the amplitude fluctuation in the frame is controlled as the power of 2 at the head of the frame, and the gain between branches is controlled. Correction,
This can be performed by a bit shift corresponding to a power of 2 over the frame from the frame head position.

The gain control circuit 12 has a branching A
Based on the gain control signal from the GC unit, the AG corresponding to the branch is
The gain of the C amplifier is controlled so as to have a ratio of a power of two, and gain correction between branches can be performed by bit shifting according to the ratio between branches.

FIG. 3 is an explanatory view of a main part of a third embodiment of the present invention, and shows a main part of an AGC unit 20. In the figure, 16 is an AGC amplifier, 17 is a demodulation unit, 21 is a gain control circuit, 31 is a power detection unit, 32 is a comparison unit, 33 is an averaging unit, and 34 is a reference value setting unit.

The power detector 31 finds the power corresponding to the amplitude by squaring the demodulation output signal from the demodulator 17 and compares the reference value from the reference value setting unit 34 with the reference value from the comparator 32. And compares the difference with the averaging unit 33
To enter. The averaging unit 33 can be composed of, for example, a first counter that counts a difference output and a second counter that counts an overflow or an underflow of the first counter. The gain control signal for the AGC amplifier 16 is obtained.

The reference value setting section 34 sets a reference value based on the gain control signal from the averaging section 33 and the gain control signal of the AGC amplifier 16 from the gain control circuit 21. This is to originally control the gain of the AGC amplifier 16 by the gain control signal of the average value per unit time from the averaging unit 33, but the gain control circuit 12 actually controls the gain of the AGC amplifier 16. Is, for example, to make the reference gain be a power of two. Therefore, by setting a reference value according to a ratio of a gain to be actually controlled to a gain to be originally controlled, Normal AGC
An operation equivalent to a circuit can be performed.

FIG. 4 is an explanatory diagram of gain control and gain correction according to the fourth embodiment of the present invention. For example, the branch 1 including the antenna 11A, the receiving unit 15A, and the AGC amplifier 16A of FIG. , A receiving unit 15B, and a branch 2 including an AGC amplifier 16B.
The amplifier is shown as an AGC amplifier.

The AGC of the branch 1 is performed by the AGC unit 20A.
The gain to be controlled for the amplifier is assumed to be A (A
1) The gain to be controlled by the AGC unit 20B for the AGC amplifier of the branch 2 is set to B (A2), and the gain control circuit 12 sets the gain A0 of the AGC amplifier of the branch 1 to A0.
= A, and the gain B0 of the AGC amplifier in the branch 2 is B0 = A * 2 {(int) (log ₂ (B / A) +0.5)} (2) Note that “*” is a multiplication symbol, “2 ＾” is a power-of-two symbol, and “(int)” is a symbol in the following parentheses () indicating truncation below the decimal point.

The gain between the branches 1 and 2 is corrected as follows:
The gain correction for the branch 1 is set to zero, and the gain of the branch 2 is set to-｛(int) (log ₂ (B / A) +0.
5) 補正 Correct by bit shift (A3). That is, A
The gain of the GC amplifier is controlled as a power of 2, and the gain is corrected by a backward shift by the number of bits corresponding to the gain. Therefore, gain correction between branches can be performed by a selector that is simpler than when a multiplier is used.

FIG. 5 is an explanatory diagram of gain control and gain correction according to the fifth embodiment of the present invention. Similar to (A1) and (A2) for branches 1 and 2 shown in FIG. The original gains of the AGC amplifiers 1 and 2 are A and B (B1) and (B2), and the gains A and B are compared (B3).

If A <B, the gain A0 = A of the AGC amplifier of the branch 1 is set as the reference gain, and the gain A0 of the branch 2 is set as the reference gain.
The gain B0 of the GC amplifier is set to a power of 2 times the reference gain A according to the equation (2). The gain correction between the branches 1 and 2 is zero for the branch 1 and − {(int) (log ₂ (B / A) +0.5)} for the branch 2.
A bit shift is performed (B3). That is, the same gain control and gain correction as in step (A3) are performed.

If not A> B, the AG of branch 2
The reference gain is set as the gain B0 of the C amplifier = B, and the gain A0 of the AGC amplifier of the branch 1 is set to a power of 2 of the reference gain B according to the equation (2). The gain correction between the branches 1 and 2 is zero for the branch 2 and − ｛(int) (log ₂ (B / A) +0.
5) Perform a bit shift (B4).

That is, for a plurality of branches, the gain of the branch with the smallest gain of the AGC amplifier is set as the reference gain, and the gains of the AGC amplifiers of the other branches are controlled so as to be a power of 2 times the reference gain. The gain correction of the reference gain branch is set to zero, and the gain correction of the other branches is performed by a bit shift corresponding to a power of two.

FIG. 6 is an explanatory diagram of gain control and gain correction according to the sixth embodiment of the present invention. FIG. 6 shows branches 1 and 2 as in the case shown in FIGS. Is assumed to be A (C1),
The original gain for controlling the AGC amplifier of the branch 2 is B (C2), the gain as a certain reference is C (C3),
The gain A0 of the AGC amplifier of the branch 1 and the gain B0 of the AGC amplifier of the branch 2 are expressed as follows: A0 = C * 2 {(int) (log ₂ (A / C) +0.5)} (3) B0 = C * 2 {(int) (log ₂ (B / C) +0.5)} (4) That is, control is performed so that the gain becomes a power of 2 according to the ratio to the reference gain C.

The gain between the branches 1 and 2 is corrected as follows:
This is performed by a bit shift corresponding to a power of 2 as indicated by the equations (3) and (4) (C4). That is, in this embodiment, the gains of the AGC amplifiers in the plurality of branches are controlled so as to be a power of 2 times the ratio of the gain to be controlled to a certain reference gain. The gain correction between each bit shift (bit selection)
This is done by:

[0043]

As described above, the maximum ratio combining method of the present invention and the diversity receiving apparatus using the method are as follows.
Diversity method for multiple branches or RAKE
By performing synchronous detection using a phase component and an amplitude component of a reference signal such as a pilot signal for a plurality of fingers of the system, a synchronous detection output signal corresponding to the amplitude component can be obtained. Thus, there is an advantage that an output signal similar to that of the maximum ratio combining can be obtained.

The gains of the AGC amplifiers of a plurality of branches are set with respect to the AGC amplifier of another branch with reference to one branch.
By controlling the GC amplification gain to be a power of two, gain correction between branches for performing maximum ratio combining can be performed by:
Bit selection by a selector, that is, bit shifting can be performed, compared to a conventional example using a multiplier,
It is possible to perform gain correction between branches by a selector having a simple configuration, and there is an advantage that an economical configuration can be achieved.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a main part of a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of a second embodiment of the present invention.

FIG. 3 is an explanatory view of a main part of a third embodiment of the present invention.

FIG. 4 is an explanatory diagram of gain control and gain correction according to a fourth embodiment of the present invention.

FIG. 5 is an explanatory diagram of gain control and gain correction according to a fifth embodiment of the present invention.

FIG. 6 is an explanatory diagram of gain control and gain correction according to a sixth embodiment of the present invention.

FIG. 7 is an explanatory diagram of a main part of a mobile device.

FIG. 8 is an explanatory diagram of a main part of a conventional receiving system.

[Explanation of symbols]

 1-1 to 1-m extraction unit 2-2 to 2-m complex conjugate unit 3-1 to 3-m synchronous detection unit 4-1 to 4-m despread processing unit 5-1 to 5-m switch 6 synthesis Unit 11A, 11B Antenna 12 Gain control circuit 15A, 15B Receiver 16A, 16B AGC amplifier 17A, 17B Demodulator 18A, 18B Despreader 19A, 19B Selector 20A, 20B AGC unit 21 Combining unit

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Morihiko Minowa 4-1-1 Kamikadanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Inside Fujitsu Limited (72) Inventor Tokuro Kubo 4-1-1 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture No. 1 Inside Fujitsu Limited

Claims (9)

[Claims] In a wireless communication system, a reference signal such as a pilot signal including an amplitude component and a phase component corresponding to a finger or a branch is extracted from a received signal, and the reference signal is extracted as a received signal corresponding to a finger or a branch. Multiplying the pilot signal, adding a synchronous detection output signal having an amplitude corresponding to the amplitude component of the pilot signal, and synthesizing the fingers or the branches. Method. 2. A maximum ratio combining method for combining with weights proportional to received signal amplitudes corresponding to a plurality of branches in a wireless communication system, wherein a gain of AGC amplification of any one of the plurality of branches is adjusted. On the other hand, the gain of the AGC amplification of the other branch is 2
A maximum ratio combining method, comprising a step of performing gain correction for a branch having a gain of a power of 2 and performing gain correction by bit shifting. 3. The gain of the branch having the smallest gain of AGC amplification among a plurality of branches is set as a reference gain, the gain of another branch is set to a power of 2 times the reference gain, and the gain correction between branches is set to the power of 2. 3. The maximum ratio combining method according to claim 2, further comprising a step of performing a bit shift corresponding to a gain of a power of 2. 4. A gain in a branch having a minimum AGC amplification gain at a head position of each frame in a frame unit of a received signal is set as a reference gain, and an AGC amplification gain in other branches is set to 2 of the reference gain. And the gain variation in the frame is controlled as a power of 2 of the reference gain, and the gain correction between the branches is performed with respect to the other branches based on the reference gain branch. 3. The maximum ratio combining method according to claim 2, further comprising a step of performing a bit shift corresponding to a gain of a power of 2. 5. A gain of AGC amplification with respect to a head of a frame of a received signal in a specific branch among a plurality of branches is set as a reference gain, and a gain of AGC amplification of another branch is set to 2 with respect to the reference gain. 5. The maximum ratio combining method according to claim 4, further comprising the step of raising to a power. 6. A gain of AGC amplification corresponding to a plurality of branches is approximated to a power-of-two ratio between branches, and
3. The maximum ratio combining method according to claim 2, further comprising a step of performing a gain correction between the branches by a bit shift corresponding to a power of a power of. 7. A diversity receiving apparatus in a wireless communication system, comprising: an extracting unit for extracting a reference signal such as a pilot signal including an amplitude component and a phase component for a finger or a branch from a received signal; A complex conjugate unit for obtaining a complex conjugate number of the reference signal extracted by the following; a synchronous detection unit that performs synchronous detection by multiplying the output signal of the complex conjugate unit and the received signal; a synchronous detection output signal of the synchronous detection unit And a combining unit for combining the signals to obtain an output signal corresponding to the maximum ratio combining. 8. A diversity receiver using a maximum ratio combining method for combining with a weight proportional to a received signal amplitude corresponding to a branch in a wireless communication system, comprising: an AGC amplifier corresponding to the branch; A corresponding to the branch for controlling the gain
A GC section, a selector corresponding to the branch for performing gain correction for maximum ratio combining by bit shift, and an AGC amplifier of one of the plurality of branches based on a gain control signal from the AGC section corresponding to the branch. A bit of the selector for controlling by a reference gain, controlling the AGC amplifiers of the other branches by a power of 2 times the reference gain, and performing gain correction corresponding to the gain of the AGC amplifier. A diversity receiver comprising: a gain control circuit that controls a shift amount; and a combining unit that combines output signals of the selectors at a maximum ratio. 9. The AGC section, comprising: a comparator for comparing a reference value with a signal power; a counter for averaging an output signal of the comparator; and a gain control signal of the AGC amplifier from the gain control circuit. 9. The diversity receiving apparatus according to claim 8, further comprising: a reference value generation unit that outputs the reference value based on an output signal of the counter.