JP2003244027A - Rake receiver and mobile communication terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the effect of waveform distortion caused in each path so as to enhance excellent RAKE reception performance and realize mobile communication with high quality even under a deteriorated wireless transmission enviroment. <P>SOLUTION: A unit 101 for demodulating a signal in a maximum path is provided with an adaptive equalizer 117 and a selection switch 116 among a plurality of units 101, 102,... configuring fingers in a RAKE receiver. The adaptive equalizer 117 is configured to be used in common for waveform equalization of a GSM reception signal and waveform equalization of a W-CDMA reception signal together with a transmission line estimate unit 113. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a CDMA (Code
The present invention relates to a RAKE receiver used for receiving a multipath signal in a mobile communication system adopting the Division Multiple Access method, and a mobile communication terminal equipped with this RAKE receiver.

[0002]

2. Description of the Related Art In a mobile communication system, multipath is generated on a radio propagation path between a base station and a mobile communication terminal due to the influence of mountains, buildings, and the like. Multipaths interfere with each other to cause frequency selective fading, which causes deterioration of communication quality. Especially in a system with a data transmission rate of several hundred Kbps or more, the effect cannot be ignored.

Therefore, in a CDMA mobile communication terminal, RAK is used.
I am using an E receiver. The RAKE receiver searches a plurality of paths arriving from the base station through different routes by a receiving circuit called a searcher, and detects a plurality of paths having a reception level equal to or higher than a predetermined level. Then, after each of the detected paths is received and demodulated by a receiving circuit called a finger, the demodulated signals are matched in phase and combined by a combiner to obtain a demodulated signal with good communication quality. is there.

[0004]

However, the signal of the path received and demodulated by each finger has a waveform distortion due to the influence of fading. Therefore, each finger may not always be able to demodulate the path at the optimum timing, and it may not be possible to exhibit sufficient RAKE reception performance.

The present invention has been made in view of the above circumstances. An object of the present invention is to reduce the influence of waveform distortion occurring in a path so that a good RAKE receiving performance can be exhibited, which results in poor performance. Another object of the present invention is to provide a RAKE receiver and a mobile communication terminal that can realize high-quality mobile communication even under a wide radio propagation environment.

[0006]

In order to achieve the above object, a RAKE receiver and a mobile communication terminal according to the present invention include a plurality of fingers which individually demodulate signals of a plurality of paths and output the demodulated signals. In addition to a combiner for combining the demodulated signals output from these fingers by combining the phases and outputting a combined demodulated signal, an equalizer is provided corresponding to at least one of the plurality of fingers. ing. The equalizer performs waveform equalization on the signal of the path demodulated by the finger.

Therefore, according to the present invention, even if waveform distortion occurs in the signal of the path due to the effect of fading, for example, the waveform of the signal of the path is equalized by the equalizer when demodulated by the finger. Therefore, a demodulated signal in which the influence of the above waveform distortion is reduced can be obtained from the finger, and thereby high quality mobile communication can be realized even in a poor wireless transmission environment.

The equalizer may be provided corresponding to the finger that demodulates the signal of the path having the maximum signal level among the signals of the plurality of paths. With such a configuration, it is possible to obtain a sufficient waveform distortion suppressing effect with one equalizer while minimizing the increase in circuit scale and complexity.

The equalizer may be an adaptive equalizer. In this case, the adaptive equalizer detects the reception timing that gives the maximum value to the signal of the path demodulated by the corresponding finger, and the known signal included in the signal of the path obtained at this detected reception timing. The delay profile is obtained from the reception result of. Then, waveform equalization is performed on the signal of the path based on this delay profile. With this configuration, the equalizer adaptively equalizes the signal of the path demodulated by the finger. Therefore, even if the occurrence of fading or the like changes, the optimum waveform equalization processing can always be performed according to this change, and a more stable waveform distortion suppressing effect can be obtained.

Further, the present invention is based on the CDMA system and TDM.
In a so-called dual-mode type mobile communication terminal compatible with two radio access methods of A method, by demodulating signals of a plurality of paths included in a received CDMA radio signal with fingers, respectively, and combining them by combining phases. A RAKE receiver that outputs a CDMA demodulated signal;
In addition to a TDMA demodulation circuit that demodulates the received TDMA radio signal and outputs a TDMA demodulation signal, an equalizer that is commonly provided for the CDMA radio signal and the TDMA radio signal and a signal selection unit are newly provided. There is. And
The signal leading means selects one of a plurality of paths of signals demodulated by the RAKE receiver and a TDMA radio signal demodulated by the TDMA demodulation circuit according to the radio access system in use, and makes this selection. One of the generated paths of the CDMA radio signal and the TDMA radio signal are input to the equalizer to perform waveform equalization processing.

Therefore, according to this mobile communication terminal, 1
Waveform equalization and CDM of TDMA radio signal by each equalizer
Both waveform equalization of the signal of one path of the A radio signal is performed. Therefore, a simple and small circuit that uses only one equalizer reduces the effect of waveform distortion and realizes high-quality demodulation regardless of whether the TDMA method or the CDMA method is used. it can.

Particularly, when an equalizer is already provided to reduce the waveform distortion of the TDMA radio signal, the equalizer for equalizing the waveform of the TDMA radio signal is used to equalize the waveform of the CDMA radio signal. Also serves as a dual purpose. In this way, TDM can be performed without newly providing an equalizer for CDMA.
It is possible to perform waveform equalization processing not only on the A radio signal but also on the CDMA radio signal, which makes it possible to obtain high quality reception performance in both TDMA and CDMA.

[0013]

1 is a circuit block diagram showing an embodiment of a mobile communication terminal according to the present invention. This mobile communication terminal uses TDMA (Time Division Multiple A).
GSM (global System for M) which is one of the ccess) methods.
obile communication) method and W-CDMA (Wideban)
So-called GSM / W-CD compatible with two wireless access methods, d-Code Division Multiple Access)
It is an MA dual mode type mobile communication terminal.

G transmitted from a GSM base station (not shown)
W transmitted from SM radio signal and W-CDMA base station
-The CDMA radio signal is received by the antenna 1 and then input to the receiving circuit (RX) 3 via the antenna duplexer 2 (DUP). The receiving circuit 3 receives the input G
The SM radio signal and the W-CDMA radio signal are mixed with the reception local oscillation signal generated from the frequency synthesizer (SYN) 4 and frequency-converted into an intermediate frequency or baseband signal. Then, the frequency-converted signal is subjected to quadrature demodulation processing and A / D conversion processing to reproduce the GSM baseband complex signal and the W-CDMA baseband complex signal, respectively, and reproduce the reproduced signal to GSM / W.
-Input to the CDMA signal processing unit 6. The frequency of the reception local oscillation signal generated by the frequency synthesizer 4 is specified by the control signal SYC output by the control unit 12.

The GSM / W-CDMA signal processing section 6 receives a GMS signal for the input GSM baseband complex signal.
Demodulation processing by the K / BPSK converter and waveform equalization processing by the adaptive equalizer are performed, and the demodulated data obtained by this is input to the compression / expansion processing unit 7. Also, the entered W
RAKE for CDMA baseband complex signals
The RAKE reception / synthesis processing by the receiver and the waveform equalization processing by the adaptive equalizer are performed, and the demodulated data obtained by this is input to the compression / expansion processing unit 7. This GSM / W
The configuration of the CDMA signal processing unit 6 will be described later in detail.

The compression / expansion processing section 7 includes an audio codec and an image codec. Then, of the input demodulated data, voice data is voice-decoded by a voice codec to reproduce a digital voice signal, and the digital voice signal is input to the PCM code processing unit 8. The PCM code processing unit 8 PCM-decodes the input digital voice signal to reproduce an analog voice signal, and outputs the analog voice signal to the reception amplifier 9. The reception amplifier 9 has the above P
The analog audio signal output from the CM code processing unit 8 is amplified and output from the speaker 10.

On the other hand, the image data of the input demodulated data is, for example, J depending on the image codec.
The digital image signal is reproduced by decoding in accordance with the PEG or MPEG4 system and input to the control unit 12. Control unit 12
Supplies the reproduced digital image signal to the liquid crystal display of the display unit 15 to display it. Further, the control unit 12 stores the audio data and the image data before decoding in the storage unit 13 as needed. When an external information terminal such as a personal digital assistant (PDA: Personal Digital Assistance) or a notebook personal computer is connected to the mobile communication terminal, an external interface (not shown) for the digital audio signal and the digital image signal is used. It is also possible to transfer to the external information terminal via the.

On the other hand, the talker's transmitted voice signal input to the microphone 11 is amplified to a proper level by the transmitter amplifier 18, and then PCM coded by the PCM code processor 8 to obtain a digital voice. The signal is input to the compression / expansion processing unit 7. Further, the transmission mail created by the control unit 12 and the digital image signal picked up by a camera (not shown) are input from the control unit 12 to the compression / expansion processing unit 7.

The compression / expansion processor 7 uses the VSELP method in the case of the GSM method and the AMR (Adaptive Multi Rate) method in the case of the W-CDMA method for the input digital audio signal according to the audio codec. Performs audio encoding processing. Further, the input digital image signal is subjected to image encoding processing by an image codec, for example, by the JPEG or MPEG4 system. And
In the case of voice-only communication, the coded voice data is supplied to the GSM / W-CDMA signal processing unit 6 as it is, while in the case of multimedia communication such as videophone communication, the coded voice data is supplied. And the image data are multiplexed, and the multiplexed data is stored in the GSM / W-CD.
It is supplied to the MA signal processing unit 6.

The GSM / W-CDMA signal processing unit 6 is
In the case of the SM system, the input voice data is GMS
The signal is modulated by the K modulation method and output to the transmission circuit (TX) 5. On the other hand, in the case of the W-CDMA method, the input multiplexed data is spread by a spreading code and the transmission circuit (TX).
Output to 5. The transmission circuit 5 is the GSM / W-CDM.
The transmission data output from the A signal processing unit 6 is quadrature-modulated, and the modulated transmission data is processed by the frequency synthesizer 4
The frequency is converted into a radio signal by synthesizing it with the transmission local oscillation signal generated from Then, after high-frequency amplification of this transmission radio signal, it is supplied to the antenna 1 via the antenna duplexer 2 and transmitted from this antenna 1 to the base station.

The input section 14 is provided with dial keys and function keys such as a call key, a power key, an end key, a volume control key and a multifunction key. The display unit 15 is provided with LEDs in addition to the liquid crystal display. In addition to the image data described above, the liquid crystal display
Received and transmitted mails, the telephone number and name of the communication partner terminal, pict information indicating the operating state of the terminal itself, etc. are displayed. Also LE
D is used to notify the incoming call and display the charging operation state of the battery 16. Reference numeral 17 denotes a power supply circuit, which generates a predetermined operating power supply voltage Vcc based on the output of the battery 16 and supplies it to each circuit unit.

By the way, the RAKE receiver of the GSM / W-CDMA signal processing unit 6 is constructed as follows. FIG. 2 is a circuit block diagram showing the configuration. This RAK
The E receiver includes a plurality of units 101, 102, ... And an addition-encoding unit 100.

The first of the units 101, 102, ...
Each unit 102, 103, except the unit 101 of
Function as a finger that demodulates a plurality of paths included in the received W-CDMA wireless signal. Each of these units 102, 103, ... Has a delay buffer 121, 131 ,.
2, 132, ... and transmission path estimators 123, 133 ,.
, And multipliers 124, 134, ... and 125, 135 ,.
With.

On the other hand, the first unit 101 is a W-CD.
A function as a finger for demodulating a path having the maximum reception level among a plurality of paths included in an MA radio signal, and GSM
It also has the function of demodulating radio signals. That is, the demodulation function of the GSM radio signal is performed by the GMSK-BPSK converter 110.
And adaptive equalizer 117. GMSK-BP
The SK converter 110 converts the GMSK-converted GSM baseband complex signal into a BPSK signal. On the other hand, the fingers are the delay buffer 111, the correlation code multiplier 112, the transmission path estimator 113, and the weighting multiplier 115.
It is composed of

The first unit 101 also uses the adaptive equalizer 117 not only for waveform equalization of GSM radio signals but also for waveform equalization of W-CDMA radio signals. Furthermore, the transmission path estimator 113 is
It is used not only for estimating the transmission path of the maximum path of the W-CDMA wireless signal but also as a training circuit for initializing the tap coefficient of the adaptive equalizer 117 at the time of receiving the GSM wireless signal.

Further, the first unit 101 has a selection switch 116 in order to share the adaptive equalizer 117 and the transmission path estimator 113. This selection switch 1
16 is a GSM / W-CDM output from the control unit 12.
One of the GSM baseband complex signal and the W-CDMA baseband complex signal is selectively fetched by the A processing selection signal SS and supplied to the delay buffer 111.

The delay buffer 111 receives the input GS.
The M / W-CDMA baseband complex signal is stored for each slot. Then, a known signal for channel estimation included in the GSM / W-CDMA baseband complex signal is extracted and supplied to the channel estimator 113. For example, G
When the SM method is selected, the training sequence for channel estimation arranged in the center of the normal burst format slot is extracted and supplied to the channel estimator 113. On the other hand, when the W-CDMA system is selected, as shown in the W-CDMA transmission signal format in FIG. 3, the pilot signal portion added to the data portion for each slot is extracted to estimate the transmission path. It is supplied to the device 113 to perform the transmission path estimation processing. And
At the end of this transmission path estimation processing, the data part of the slot is read and supplied to the adaptive equalizer 117.

The transmission path estimator 113 receives the received GSM.
/ W-CDMA The transmission channel estimation is performed by calculating the autocorrelation between the known signal for channel estimation included in the complex signal and the known pattern prepared in advance. FIG. 4 is a circuit block diagram showing the configuration of the transmission path estimator 113.

GSM supplied from the delay buffer 111
The training sequence in the baseband complex signal and the pilot signal part in the W-CDMA baseband complex signal are delayed by one sample by delay circuits 221, 222, ...
, ..., 21n are input. Correlators 210, 211,
, 21n are the input known signal and GSM / W-
The correlation value with the known pattern of the correlation code generated from the CDMA correlation code generator 200 is calculated. Then, the calculated correlation value is given to the adaptive equalizer 117 as transmission path estimated values (delay profiles) f0, f1, ..., Fn.

The GSM / W-CDMA correlation code generator 200 is provided with the GSM / W-C supplied from the control unit 12.
According to the DMA processing selection signal SS, the known pattern of the GSM correlation code and the known pattern of the W-CDMA correlation code are selectively generated. The training sequence pattern is a known pattern of the correlation code for GSM.
On the other hand, the known pattern of the pilot signal part is used as the known pattern of the W-CDMA correlation code.

The adaptive equalizer 117 uses the waveform distortion components contained in the data section supplied from the delay buffer 111 as the transmission path estimation values (delay profiles) f0 and f1 obtained by the transmission path estimator 113. , ..., Fn are removed based on, for example, the following configuration. FIG. 5 is a circuit block diagram showing the configuration.

That is, the adaptive equalizer 117 includes the delay circuit 3
, 31k, and a tap coefficient multiplier 32
, 32k, an adder 330, and a tap coefficient generation unit, which is a (k + 1) th-order transversal filter. The tap coefficient generator includes delay units 340, 341, ..., 34k and adders 350, 35.
, ..., 35k and weight multipliers 360, 361, ..., 3
6k and a determination part.

The judgment section is composed of a judgment unit 370 and a subtractor 380.
The subtractor 380 obtains the difference between the output from the determiner 370 and the input to the determiner 370.
This difference represents a deviation from the ideal decision point, and this deviation is used as the correction amount of the tap coefficient, and the weight multipliers 360, 361,
…, Given to 36k. Weight multipliers 360, 361,
, 36k finds a value obtained by multiplying the given correction amount of the tap coefficient by a feedback weighting coefficient, and outputs the value as an adder 35
The tap coefficient is updated by adding it to the initial value of the tap coefficient at 0, 351, ..., 35k. Then, the updated tap coefficient is multiplied by the tap coefficient multipliers 320, 32.
1, ..., 32k.

The decision output of the decision unit 370 is input to the decimation unit 390. The decimator 390 includes a controller 12
The determination output is converted into a sample rate of 1 / m according to the sample thinning ratio m given by Then, the determination output after the sample rate conversion is input to the correlation code multiplier 112.

The correlation code multiplier 112 comprises a correlation code generator 400 and a multiplier 410. And
In the multiplier 410, the judgment output after the sample rate conversion is multiplied with the correlation code generated from the correlation code generator 400, and the multiplication output is input to the weighting multiplier 115 as demodulated data equalized. To do. The correlation code generator 400 operates according to the GSM / W-CDMA processing selection signal SS, generates a correlation code when the W-CDMA system is selected, and outputs "1" when the GSM system is selected. Generates a continuous code of.

The weighting multiplier 115 is used in the other unit 1
02, 103, ... Weighting multipliers 125, 135 ,.
Similarly, the demodulated data output from the correlation code multiplier 112 is multiplied by the weighting coefficient according to the reception level of the path. The addition-encoding unit 100 uses the GSM / W-CD
The weighting multiplier 11 operates according to the MA processing selection signal SS, and when the W-CDMA system is selected.
The demodulated data of the respective paths output from 5, 125, 135, ... Are added and combined, and the added and combined demodulated data are supplied to the compression / expansion processing unit 7. On the other hand, when the GSM system is selected, the demodulated data output from the weighting multiplier 115 is directly used for the compression / expansion processing unit 7
Supply to.

Next, the operation of the RAKE receiver of the mobile communication terminal configured as described above will be described.

(1) When the W / CDMA system is selected During communication by the W / CDMA system, a plurality of paths included in the W-CDMA wireless signal are detected by a searcher (not shown), and each of the detected paths is detected. The units 101, 102, 103, in order from the one with the highest reception level,
Assigned to ... Then, each unit 101, 10
, 103 despread the paths assigned to each of them, and execute demodulation processing. At this time,
The units 102, 103, ... Perform normal finger processing, but the unit 101 to which the maximum path is assigned performs despreading and demodulation processing including adaptive equalization processing as follows.

That is, when the W / CDMA system is selected, the control unit 12 outputs the GSM / W-CDMA process selection signal SS instructing the process by the W / CDMA system. Therefore, the selection switch 116 selects the W-CDMA baseband complex signal. Then, the selected W-CDMA baseband complex signal is temporarily held in the delay buffer 111 for each slot, and in this state, the pilot signal portion in the slot is extracted and input to the transmission path estimator 113.

In the transmission path estimator 113, the delay circuit 22
, 22n and correlators 210, 211,
, 21n, the correlation value between the pilot signal input from the delay buffer 111 and the known pattern of the pilot signal generated from the GSM / W-CDMA correlation code generator 200 is calculated. That is, the autocorrelation of the pilot signal is obtained. Then, the calculated autocorrelation value is the channel estimation value (delay profile) f0, f1,
, Fn are provided to the adaptive equalizer 117.

The adaptive equalizer 117 fetches from the delay buffer 111 based on the transmission channel estimation values (delay profile) f0, f1, ..., Fn given as tap coefficients from the transmission channel estimator 113. Adaptive equalization processing is performed to remove the waveform distortion component contained in the data portion of the W-CDMA baseband complex signal.

That is, first, with respect to the delay devices 340 to 34k, the complex conjugates f0 *, f1 *, ... Of the transmission path estimation values f0, f1, ..., Fk (k ≦ n) given from the transmission path estimator 113 are given. ， Fk *
Is set as the initial value of the tap coefficient. After that, the difference between the judgment output of the judgment unit 370 and the new input to the judgment unit 370 is obtained in the subtractor 380, and this difference is used as the correction amount of the tap coefficient, the weight multipliers 360, 361, ..., 36k.
Given to. Weight multipliers 360, 361, ..., 36k
Then, the given correction amount of the tap coefficient is multiplied by the feedback weighting coefficient, and the output thereof is added by the adders 350, 351 ,.
At 35k, the tap coefficient is added to the current tap coefficient value to update the tap coefficient. Then, the updated tap coefficient is given to the tap coefficient multipliers 320, 321, ..., 32k and multiplied by the data part of the W-CDMA baseband complex signal.

That is, in the adaptive equalizer 117, the subtractor 3
Output of the determiner 370 and the determiner 37
The tap coefficient is sequentially updated so that the difference from a new input to 0 approaches zero, that is, approaches the ideal determination value. Therefore, by passing the data part of the W-CDMA baseband complex signal through the adaptive equalizer 117, it is possible to obtain the determination output from which the waveform distortion component is removed.

Then, the decision unit 370 of the adaptive equalizer 117 is used.
The judgment output obtained by
The sample rate is converted into the symbol rate by m. For example, when a received signal is input at a sample rate four times the symbol rate of the W-CDMA system, the decimator 390 converts the rate to ¼. Then, the determination signal after the rate conversion is input to the correlation code multiplier 112 as the output of the adaptive equalizer 117.

In the correlation code multiplier 112, the rate-converted decision signal is multiplied by the correlation code generated from the correlation code generator 400 to obtain despread demodulated data of the maximum path. The demodulated data of the maximum path is weighted by the weighting multiplier 115, and then added to another unit 10 in the addition-encoding unit 100.
2, 103, ... are added to and demodulated with the demodulation data of the respective paths output from the weighting multipliers 125, 135, ..., and the added and demodulated data are supplied to the compression / expansion processing unit 7 as the output of the RAKE receiver. To be done.

Therefore, among the signals of a plurality of paths included in the W-CDMA baseband signal, the signal of the path having the maximum reception level is the adaptive equalizer 1 of the unit 101.
After the waveform distortion is removed by 17, the signal can be despread and demodulated. Therefore, high-quality W-CDMA demodulated data in which the influence of waveform distortion is effectively suppressed, as compared with the conventional case in which the signal of the maximum path is despread as it is, demodulated, and added and combined with the signals of other paths. Can be obtained.

(2) When the GSM system is selected During the communication period using the GSM system, the receiving circuit 3 causes the GS
When the M baseband demodulated signal is output, this GSM baseband demodulated signal is first converted into the GMSK-BPSK converter 1.
At 10, the GMSK modulated signal is converted into the BPSK modulated signal. That is, the phase shift is converted into a signal form that enables symbol determination based on the phase position.

When the GSM system is selected, the control unit 12 instructs the GSM system to perform the GSM / W-process.
The CDMA processing selection signal SS is output. Therefore, in the selection switch 116, the GMSK-BPSK converter 1
The BPSK signal output from 10 is selected. Then, the selected BPSK signal is transmitted to the delay buffer 1
In 11, the training sequence is temporarily held for each slot, and in this state, the training sequence inserted in the central portion of the slot is extracted and input to the transmission path estimator 113.

In the transmission path estimator 113, the delay circuit 22
, 22n and correlators 210, 211,
, 21n, the training sequence input from the delay buffer 111 and the GSM / W-CDMA.
The correlation value with the known pattern of the training sequence generated from the correlation code generator 200 is calculated. That is, the autocorrelation of the training sequence is taken. Then, the calculated correlation value is used as the channel estimation values f0, f1,
, Fn are provided to the adaptive equalizer 117.

In the adaptive equalizer 117, the transmission channel estimation values f0, f1, ..., Fn given from the transmission channel estimator 113 are used as they are as initial values of tap coefficients. Thereafter, the tap coefficient is updated based on the difference between the signals before and after the determination obtained from the subtractor 380, that is, the tap coefficient correction value.
Then, based on this updated tap coefficient, waveform equalization processing of the data portion of the BPSK signal read from the delay buffer 111 is performed, and the determination signal of the determination unit 370 after this equalization processing is The output of the adaptive equalizer 117 is given to the compression / expansion processing unit 7.

When the sample rate of the decision signal of the decision unit 370 is higher than the symbol rate, the rate of the decision signal is converted into the symbol rate by the decimation unit 390. Further, in the GSM communication, spreading by the correlation code is not performed. Therefore, the correlation code generator 400 generates a continuous code of "1".
Therefore, the decision signal output from the adaptive equalizer 117 is directly input to the compression / expansion processing unit 7 and decoded.

As described above, in this embodiment, RA
In the KE receiver, the adaptive equalizer 117 and the selection switch 116 are provided in the unit 101 that demodulates the maximum path among the plurality of units 101, 102, ... That constitute the finger, and the adaptive equalizer 117 is used for channel estimation. It is also used for equalizing the waveform of the GSM received signal and for equalizing the waveform of the W-CDMA received signal.

For this reason, not only the waveform equalization processing of the GSM baseband complex signal but also the maximum path of the W-CDMA baseband complex signal can be achieved only by providing a set of adaptive equalizer 117 and transmission path estimator 113. It is also possible to perform processing such as the waveform. That is, the W-CDM is not provided without newly providing the adaptive equalizer 117 and the transmission path estimator 113, that is, without increasing the size and complexity of the circuit configuration.
It is possible to remove the waveform distortion of the maximum path that has the greatest influence on the reception quality of the A demodulated signal and effectively improve the reception quality of the W-CDMA demodulated signal.

The present invention is not limited to the above embodiment. For example, in the above embodiment, the case where the adaptive equalizer 117 is provided only in the unit (finger) 101 that demodulates the maximum path has been described as an example. However, the present invention is not limited to this, and the adaptive equalizer 117 may be provided in two or more units among the plurality of units 101, 102, ... Within the range of the allowable circuit scale. With this configuration, since despreading can be performed after performing adaptive equalization processing on two or more paths, W-CDMA
It is possible to further improve the reception quality of demodulated data.

In the above embodiment, GMSK-BPS is used.
Although the K converter 110 is provided inside the unit 101, it may be provided outside the unit 101.

Further, in the above embodiment, GSM / W-C
Although the description has been given by taking the DMA dual mode type mobile communication terminal as an example, the present invention can be applied to other TDMA / CDMA dual mode type mobile communication terminals. An adaptive equalizer may be provided in the RAKE receiver of the CDMA mobile communication terminal.

Other types of mobile communication terminals and their configurations,
The circuit configuration of each finger of the RAKE receiver, the circuit configuration of the transmission line estimator and the adaptive equalizer, etc. can be variously modified and implemented without departing from the scope of the present invention.

[0058]

As described above in detail, according to the present invention, a plurality of fingers that individually demodulate signals of a plurality of paths included in a multipath propagation signal and output the demodulated signals, and the fingers that are output from these fingers. In addition to the synthesizer that synthesizes the path demodulated signals by matching the phases and outputs the demodulated signal, an equalizer is provided corresponding to at least one of the plurality of fingers. With this equalizer, waveform equalization is performed on at least one of the signals of the paths demodulated by the fingers.

Therefore, according to the present invention, it is possible to reduce the influence of the waveform distortion occurring in each path and to exhibit a good RAKE receiving performance, which allows high quality mobile communication even in a bad radio transmission environment. It is possible to provide a RAKE receiver and a mobile communication terminal capable of performing the above.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a mobile communication terminal according to the present invention.

FIG. 2 is a circuit block diagram showing the configuration of a RAKE receiver provided in the GSM / W-CDMA signal processing unit shown in FIG.

FIG. 3 is a diagram showing a slot configuration of a signal transmitted by the W-CDMA system.

4 is a circuit block diagram showing a configuration of a transmission path estimation unit provided in the RAKE receiver shown in FIG.

5 is a circuit block diagram showing a configuration of an adaptive equalizer provided in the RAKE receiver shown in FIG.

[Explanation of symbols]

1 ... antenna 2 ... Antenna duplexer (DUP) 3 ... Receiving circuit (RX) 4 ... Frequency synthesizer (SYN) 5 ... Transmission circuit (TX) 6 ... CDMA signal processing unit 7 ... Compression / decompression processing unit 8 ... PCM code processing unit 9 ... Receiver amplifier 10 ... speaker 11 ... Microphone 12 ... Control unit 13 ... storage unit 14 ... Input section 15 ... Display 16 ... Battery 17 ... Power supply circuit 18 ... Transmitter amplifier 100 ... Addition-encoding unit 101 ... Unit for both GSM / W-CDMA 102, 103, 104 ... Units for W-CDMA 110 ... GMSK-BPSK converter 111, 121, ... Delay buffer 112, 122, ... Correlation code multiplier 113 ... Transmission line estimator for both GSM / W-CDMA 123, 133, ... Transmission channel estimator for W-CDMA

Claims (8)

[Claims] 1. A plurality of fingers that individually demodulate signals of a plurality of paths included in a multipath propagation signal and output the demodulated signals, and a path demodulated signal output from these fingers are combined in phase. And a combiner that outputs a combined demodulated signal, and an equalizer that is provided corresponding to at least one of the plurality of fingers and that performs waveform equalization on the signal of the path demodulated by the finger. RAKE characterized by having
Receiving machine. 2. The RAKE receiver according to claim 1, wherein the equalizer performs waveform equalization on a signal of a path having a maximum signal level among signals of the plurality of paths. 3. The equalizer detects a reception timing that gives a maximum value to a signal of a path demodulated by a corresponding finger, and a known signal included in the signal of the path obtained at the detected reception timing. 3. The RA according to claim 1 or 2, wherein a delay profile is obtained from the reception result of the signal, and the waveform equalization is adaptively performed on the signal of the demodulated path based on the delay profile.
KE receiver. 4. A CDMA (Code D) transmitted from a base station.
ivision Multiple Access) A radio circuit that receives a radio signal, a RAKE receiver that demodulates the CDMA radio signal received by this radio circuit and outputs the demodulated signal, and a demodulated signal that is output from this RAKE receiver. The RAKE receiver individually demodulates signals of a plurality of paths included in the CDMA radio signal received by the radio circuit, and outputs a path demodulation signal. A plurality of fingers, a combiner for combining the path demodulated signals output from the fingers with each other in phase, and outputting the demodulated signal; and a finger provided corresponding to at least one of the plurality of fingers. A mobile communication terminal comprising: an equalizer that performs waveform equalization on a signal of a path demodulated by. 5. The mobile communication terminal according to claim 4, wherein the equalizer performs waveform equalization on a signal of a path having a maximum signal level among signals of the plurality of paths. 6. The equalizer detects a reception timing that gives a maximum value to a signal of a path demodulated by a corresponding finger, and a known signal included in the signal of the path obtained at the detected reception timing. 6. The mobile communication according to claim 4 or 5, wherein the delay profile is obtained from the reception result of the signal and the waveform equalization is adaptively performed on the signal of the demodulated path based on the delay profile. Terminal. 7. The CDMA transmitted from the first base station
(Code Division Multiple Access) A first radio circuit that receives a radio signal and a TDMA (Time Division) transmitted from a second base station.
Multiple Access) A second radio circuit for receiving a radio signal and signals of a plurality of paths included in the CDMA radio signal received by the first radio circuit are respectively demodulated by fingers and then combined in phase. A RAKE receiver that outputs a CDMA demodulated signal by the RAKE receiver; a TDMA demodulator circuit that demodulates the TDMA radio signal received by the second radio circuit and outputs a TDMA demodulated signal; Signal selecting means for selecting one of the signals on the path and the TDMA radio signal demodulated by the TDMA demodulation circuit according to the radio access scheme in use; and the CDMA radio signal selected by the signal selecting means. An equalizer for performing waveform equalization on the signal on the signal path and the TDMA radio signal, respectively. Mobile communication terminal. 8. The selection circuit uses a signal of a path having a maximum signal level among a plurality of signals of paths included in the CDMA radio signal and a TDMA radio signal demodulated by the TDMA demodulation circuit. The mobile communication terminal according to claim 7, wherein the mobile communication terminal is selected in accordance with the existing wireless access method.