JP2002368650A - Cdma demodulation module and radio terminal provided with the demodulation module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a CDMA demodulation module, that can correct frequency distortion components so as to furthermore reduce a reception code error, thereby further enhancing the reception characteristics. SOLUTION: A frequency characteristics detection section 182 obtains a frequency characteristic Rm, on the basis of a code error Rj between a reception signal after error correction and a reception code before correction, detected by an error correction section 210, and a correlation calculation section 183 calculates the correlation, between the frequency characteristic Rm and a frequency characteristic Ro of previous frame stored in a memory 184. Then the calculated correlation value is compared with threshold, and only when the correlation value is equal to the threshold or more, will the reception code error Rn of a current frame be given to an adaptive equalizer 200 for updating a tap coefficient and a reception code Rq after RAKE synthesis which has been subjected to equalization processing, according to the updated tap coefficient is given to the error correction section 210 via a changeover switching circuit 190.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a CDMA (Code
The present invention relates to a CDMA demodulation module provided in a wireless terminal device adopting a Division Multiple Access (DM) method and a wireless terminal device provided with this demodulation module.

[0002]

2. Description of the Related Art In recent years, in the field of mobile communications, a system employing a CDMA system as a wireless access system has attracted attention.

[0003] A CDMA mobile communication system uses a spread spectrum communication system, and performs communication as follows, for example. That is, the communication device on the transmitting side first modulates digitized audio data and image data by a digital modulation method such as the PSK modulation method. Next, the modulated data is converted into a wideband baseband signal using a spreading code, and the spread transmission signal is frequency-converted into a radio frequency signal and transmitted.

On the other hand, a communication device on the receiving side first despreads a received radio signal using the same code as the spreading code used in the communication device on the transmitting side. Then, digital demodulation is performed on the despread received signal by a digital demodulation method such as a PSK demodulation method to reproduce received data.

In the CDMA system, (1) it is easy to maintain a high communication quality against a change in the communication environment such as multipath fading by using a spread spectrum technique. (2) By using the RAKE reception method, soft handover is possible, and stable handover without instantaneous interruption of communication can be realized. And so on.

Incidentally, a CDMA demodulation module of a wireless terminal device used in this type of system is configured as follows, for example. FIG. 3 is a circuit block diagram showing the configuration.

That is, the CDMA demodulation module includes a plurality of fingers 111 to 11n, and a reception signal Ra corresponding to a plurality of paths output from a radio unit (not shown) is first input to these fingers 111 to 11n. Each of the fingers 111 to 11n performs the despreading process on the received signal Ra at the despreading timing assigned in advance by using the same spreading code used for spreading on the transmission side.

FIG. 4 is a signal waveform diagram for explaining the despreading process in the fingers 111 to 11n. As shown in the figure, an input received signal Ra is first despread at a chip rate by a spreading code to become a decoded signal. The decoded signal is integrated and then binarized in synchronization with the latch signal, thereby outputting baseband reception codes Rb1 to Rbn.

The baseband reception codes Rb1 to Rbn output from the fingers 111 to 11n are timing-adjusted by the timing adjusters 121 to 12n so that they have the same phase, and then transmitted to the transmission path estimators 131 to 13n. Is entered. The transmission path estimating units 131 to 13n calculate the transmission path distortion of the received codes Rc1 to Rcn, and correct the transmission path distortion. Then, the received codes Rd1 to Rdn in which the transmission line distortion has been corrected are combined in a symbol unit by the RAKE combining section 140, and then deinterleaved by the deinterleave section 150, and the error correction section 1
60 is input.

The error correction section 160 performs, for example, Viterbi decoding on the input received code Rf. The error-corrected received code Rg is input to a signal processing section (not shown) for reproducing information. Processing is performed. Reference numeral 170 denotes an error detection unit using, for example, a CRC code, which detects a code error included in the reception code Rf output from the deinterleaving unit 150 and outputs a detection signal Rh
Is given to the signal processing unit.

[0011]

However, such a conventional CDMA demodulation module has the following problems to be solved. In other words, generally, the received codes are shifted from the ideal point A as shown in FIG. Therefore, the transmission path estimation units 131 to 13n calculate the average value B of the plurality of received codes distributed in the range W, and calculate the amplitude distortion from the amplitude Gr of the average value B and the amplitude G of the ideal point A. Further, the phase distortion θ is calculated from the phase of the average value B and the phase of the ideal point A. Then, based on the calculated amplitude distortion and phase distortion θ, the amplitudes and phases of the input received codes Rc1 to Rcn are corrected.

However, the distortion component corrected by the transmission path estimating units 131 to 13n is the difference between the average value B and the ideal point A. That is, the distortion component of the phase characteristic and the amplitude characteristic included in the received code can be corrected, but the other distortion component, for example, the distortion component of the frequency characteristic cannot be corrected.

The present invention has been made in view of the above circumstances, and its object is to enable not only the phase distortion and the amplitude distortion components but also the frequency distortion component to be corrected, thereby enabling the reception code to be corrected. An object of the present invention is to provide a CDMA demodulation module capable of further lowering an error rate and further improving reception characteristics, and a wireless terminal device provided with the demodulation module.

[0014]

In order to achieve the above object, according to the present invention, received signals corresponding to a plurality of paths are despread by fingers, and then transmission line distortion is corrected to perform RAKE combining. In a CDMA demodulation module for correcting an error in a received code by an error correction unit, an adaptive equalization unit is provided to detect a code error between a received code before error correction by the error correction unit and a received code after error correction. By updating the tap coefficient of the adaptive equalizing means based on the detected code error,
The combined reception code is subjected to equalization processing based on the updated tap coefficients, and the reception code after the equalization processing is subjected to error correction processing.

Therefore, according to the present invention, the received code, whose frequency characteristic has been equalized by the adaptive equalizing means, is subjected to error correction processing, so that the frequency of the transmission line distortion that cannot be completely corrected by the transmission line estimating unit is obtained. Error correction can be performed after correcting the components. For this reason, the error rate of the received code is reduced, so that the reception quality can be improved.

Further, according to the present invention, when operating the adaptive equalizing means, a frequency characteristic corresponding to the code error detected by the code error detecting means is obtained, and a time correlation of the frequency characteristic is obtained. Originally RAKE
It is determined whether the residual transmission path distortion included in the combined received code is within a predetermined range. If it is determined that the residual transmission path distortion is within a predetermined range, the adaptive equalizing means updates the tap coefficients and equalizes the received code. The received code after the conversion is controlled to be input to the error correction unit.

If it is determined that the residual transmission line distortion exceeds a predetermined range, the received code subjected to RAKE combining is replaced with the equalized output of the adaptive equalizing means. The data is input to the error correction unit.

Therefore, according to the present invention, the adaptive equalizing means is used only when it is determined that the change in the residual transmission line distortion included in the received code after RAKE combining is relatively small,
If it is determined that the change in residual transmission line distortion is large, R
The received code after AKE combining is directly provided for error correction processing. For this reason, when the transmission path characteristics change significantly, it is possible to prevent the erroneous equalization processing from being performed in the adaptive equalization means, thereby stabilizing the frequency distortion correction processing using the adaptive equalization means. Can be implemented.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a CDM according to the present invention.
FIG. 2 is a circuit block diagram illustrating a configuration of a mobile communication terminal that is an embodiment of a wireless terminal device including an A demodulation module.

A multipath radio signal transmitted from a base station (not shown) is received by an antenna 1 and then input to a receiving circuit (RX) 3 via a duplexer 2 (DUP). In the receiving circuit 3, the radio signal is mixed with the receiving local oscillation signal output from the frequency synthesizer (SYN) 4 and frequency-converted into an intermediate frequency signal. Note that the frequency of the reception local oscillation signal generated from the frequency synthesizer 4 corresponds to the control signal SYC
Directed by

The received intermediate frequency signal is subjected to a despreading process in the CDMA signal processing unit 6 using a spreading code assigned to the receiving channel, and for example, QPSK.
Quadrature demodulation corresponding to the modulation method is performed, thereby obtaining received data. The received data is input to the compression / decompression processing section 7 after error correction decoding processing using Viterbi decoding or the like is performed.

The compression / decompression processing unit 7 performs a predetermined decoding process on the received data output from the CDMA signal processing unit 6 for each medium, thereby reproducing the received voice data and the received packet data. The received voice data is sent to the PCM code processing unit 8, and the received packet data such as electronic mail is sent to the control unit 12.

The PCM code processing section 8 includes a compression / decompression processing section 7
PCM decoding of the received voice data supplied from is performed to reproduce an analog reception signal. This analog reception signal is amplified by the reception amplifier 9 and then output from the speaker 10 as loudspeaker.

The control unit 12 depackets the received packet data such as the e-mail output from the compression / decompression processing unit 7 and stores it in the storage unit 13. It is read out and displayed on the display unit 15. When a notebook personal computer or the like is connected to the mobile communication terminal, the received packet data can be output to the personal computer via an external interface (not shown).

On the other hand, the input voice signal of the speaker input to the microphone 11 during the voice communication is amplified to an appropriate level by the transmission amplifier 18, and then the PCM code processing unit 8
Is subjected to PCM encoding processing, and is input to the compression / decompression processing unit 7 as transmission audio data. In addition, packet data such as an e-mail created by the control unit 12 is input from the control unit 12 to the compression / decompression processing unit 7.

The compression / expansion processing unit 7 performs P
The transmission audio data output from the CM code processing unit 8 is compressed into a signal having a format corresponding to the data rate specified by the base station, further subjected to error correction coding processing, and then output to the CDMA signal processing unit 6. . On the other hand, at the time of transmitting packet data, the transmission packet data output from the
Output to MA signal processing unit 6.

The CDMA signal processing section 6 performs, for example, QPSK modulation on the carrier signal using the transmission data compressed by the compression / decompression processing section 7, and applies the spread code assigned to each transmission channel to the modulated carrier signal. To perform a spread spectrum process. Then, the transmission signal subjected to the spread spectrum is output to the transmission circuit (TX) 5.

The transmission circuit 5 combines the above-mentioned spread-spectrum transmission signal with a transmission local oscillation signal generated by the frequency synthesizer 4 and frequency-converts it into a radio frequency signal. Then, based on the transmission data rate notified by the control unit 12, the transmission circuit 5 amplifies only the effective portion of the radio frequency signal at a high frequency and outputs it as a transmission radio frequency signal. The transmission radio frequency signal output from the transmission circuit 5 is supplied to the antenna 1 via the antenna duplexer 2 and transmitted from the antenna 1 to the connected base station.

The input unit 14 is provided with a key group such as a dial key, a transmission key, a power key, an end key, a volume control key, and a mode designation key. The display unit 15 is provided with an LCD display and an LED lamp. L
The CD display displays the telephone number of the terminal of the communication partner, the operating state of the terminal itself, transmitted and received mails, and the like. The LED lamp is used for displaying a state of the battery 16 such as a discharge state. Reference numeral 17 denotes a power supply circuit which generates a predetermined operation power supply voltage Vcc based on the output of the battery 16 and supplies it to each circuit section.

The CDMA demodulation module provided in the CDMA signal processing unit 6 is configured as follows. FIG. 2 is a circuit block diagram showing the configuration. 3, the same parts as those in FIG. 3 are denoted by the same reference numerals, and detailed description is omitted.

The CDMA demodulation module of this embodiment includes an error correction unit 210 having a function of detecting a received code error.
, An adaptive equalizer 200, an equalization control unit 180, and a changeover switch circuit 190.

The equalization control section 180 includes an interleave section 181, a frequency characteristic detection section 182, a correlation calculation section 183, a memory 184, and a deinterleave section 185. The interleaving section 181 interleaves the received code error Rj detected by the error correction section 210 according to the same rule as the interleaving rule applied to the received signal Ra. The frequency characteristic detection unit 182
The received code error Rk output from the interleaving section 181 is output as it is to the correlation calculating section 183 as Rn, and the frequency characteristic Rm of the received code error Rk is calculated. The calculation of the frequency characteristic Rm is performed by Fourier transforming the received code error Rk.

The correlation detecting section 183 calculates the frequency characteristic Rm corresponding to the received code error Rk in the current frame output from the frequency characteristic detecting section 182 and the received code error Rk one frame before stored in the memory 184. The correlation with the corresponding frequency characteristic Ro is calculated. Then, the calculated correlation value is compared with a preset threshold value.

As a result of this comparison, if the correlation value is equal to or larger than the threshold value, the received code error Rn of the current frame supplied from the frequency characteristic detecting section 182 is used as the tap coefficient update data R
The frequency characteristic Rm of the current frame is stored in the memory 184 while being given to the adaptive equalizer 200 as p. At the same time, a switching control signal Ri for switching the switch circuit 190 to the adaptive equalizer 200 side is generated and provided to the switch circuit 190.

On the other hand, as a result of the comparison, if the correlation value is smaller than the threshold value, the received code error Rn of the current frame is not supplied to the adaptive equalizer 200 and the memory 18
4 is not updated.
Further, a switching control signal Ri for switching the changeover switch circuit 190 to the RAKE combining section 140 is generated and given to the changeover switch circuit 190.

The adaptive equalizer 200 includes the correlation calculator 18
The tap coefficient is updated in accordance with the tap coefficient configuration data Rp given from No. 3 and equalization processing is performed on the combined reception code Re output from the RAKE combining section 140 in accordance with the updated tap coefficient. Then, reception code Rq after this equalization processing is output to deinterleave section 185.

The deinterleaver 185 deinterleaves the received code Rq output from the adaptive equalizer 200 according to the same rule as the deinterleave rule used by the deinterleaver 150. Is input to the error correction unit 210 and the error detection unit 170 via the changeover switch circuit 190.

Next, the operation of the RAKE demodulation module configured as described above will be described. The reception signal Ra output from the reception circuit 3 is input to each of the plurality of fingers 111 to 11n, where it is despread using a spreading code whose phase is set in advance corresponding to each path. Then, the baseband reception code Rb obtained by the despreading process
1 to Rbn are input to the transmission path estimators 131 to 13n after their timings are adjusted by the timing adjusters 121 to 12n so that their phases match. Transmission channel estimation unit 1
In 31 to 13n, the input received codes Rc1 to Rcn
, In particular, phase distortion and amplitude distortion are calculated, and these distortions are corrected. The received codes Rd1 to Rdn in which the transmission line distortion has been corrected are combined in a symbol unit by the RAKE combining unit 140, then deinterleaved by the deinterleave unit 150, and input to the error correction unit 160 via the changeover switch 190. Is done.

When the deinterleaved received code Rf is input, the error correction section 210 performs error correction decoding processing of the input received code Rf, and the error-corrected received code Rg and error A reception code error Rj from the reception code Rf before correction is detected.

In the equalization control section 180, the detected received code error Rj is interleaved by an interleave section 181 and then input to a frequency characteristic detecting section 182, which is Fourier-transformed by the frequency characteristic detecting section 182 to obtain the received code error. The frequency characteristic of the error Rj is determined.

The correlation calculating section 183 calculates a correlation value between the frequency characteristic Rm of the current frame obtained by the frequency characteristic detecting section 182 and the frequency characteristic Ro of the received code error of one frame before stored in the memory 184. Is calculated. Then, the correlation value is compared with a preset threshold value.

Now, suppose that the correlation value is greater than or equal to the threshold value. In this case, it is determined that the change in the channel characteristics from the previous frame to the current frame is within a range that adaptive equalizer 200 can follow. Therefore, the correlation calculation unit 18
3 gives the adaptive equalizer 200 the received code error Rn of the current frame as tap coefficient update data Rp.
At the same time, the frequency characteristic Ro of the previous frame stored in the memory 184 is updated to the frequency characteristic Rm of the current frame. Furthermore, a changeover switch circuit 1
A switching control signal Ri for switching 90 to the adaptive equalizer 200 side is generated, and the switching control signal Ri is supplied to the switching circuit 190.

Accordingly, in the adaptive equalizer 200, the tap coefficient is updated according to the received code error of the current frame, and according to the updated tap coefficient, the received code Re after RAKE synthesis is equalized. You. Then, the equalized received code Rq is deinterleaved by the deinterleaver 185 and then input to the switch circuit 190.

At this time, the changeover switch circuit 190
Are switched to the deinterleave unit 185 side by the switching control signal Ri given from the correlation calculation unit 183. Therefore, in this case, the reception code Rr that has been subjected to the above equalization processing is input to the error correction unit 210 via the switch circuit 190. Therefore, the error correction unit 2
In 10, an error correction decoding process is performed on the reception code Rr that has been equalized by the adaptive equalizer 200, and the subsequent compression / decompression processing unit 7 performs error correction on the reception code Rr that has been subjected to the equalization processing. Received reception code Rg is input.

On the other hand, it is assumed that the correlation value has fallen below the threshold value. In this case, the change in the transmission path characteristics from the previous frame to the current frame is large, and it is determined that the adaptive equalizer 200 cannot follow. Therefore, the correlation calculation unit 183
Does not supply the tap coefficient update data Rp to the adaptive equalizer 200 and does not update the frequency characteristic Ro stored in the memory 184. At the same time, a switching control signal Ri for setting the changeover switch circuit 190 on the RAKE combining section 140 side is generated and provided to the changeover switch circuit 190.

Therefore, the error correction unit 210 includes RAK
Deinterleaving section 1 after output from E combining section 140
The received code Rf deinterleaved in 50 is input as it is. Therefore, the error correction section 210 performs an error correction process on the received code Rf not passing through the adaptive equalizer 200, and supplies the error-corrected received code to the compression / decompression processing section 7.

As described above, in this embodiment, based on the code error Rj between the received code after error correction detected by the error correction unit 210 and the received code before correction, the frequency characteristic detection unit 182 uses A frequency characteristic Rm is obtained, and a correlation between the frequency characteristic Rm and the frequency characteristic Ro one frame before stored in the memory 184 is calculated by the correlation calculator 183. Then, the calculated correlation value is compared with a threshold value, and only when the correlation value is equal to or greater than the threshold value, the received code error Rn of the current frame is given to the adaptive equalizer 200 to update the tap coefficient, The received code Rq after RAKE combining, which has been equalized in accordance with the updated tap coefficients, is input to the error correction unit 210 via the switch circuit 190.

Therefore, according to the present invention, the adaptive equalizer 20
Since the received code Rq whose frequency characteristics have been equalized by 0 is subjected to error correction processing, the transmission path estimation units 131 to 13
Error correction processing can be performed after correcting the frequency component of the transmission path distortion that could not be completely corrected in n. For this reason, the error rate of the received code is reduced, so that the reception quality can be improved.

Further, the inter-frame correlation of the frequency characteristic of the received code error is detected, and the adaptive equalizer 200 is operated only when the inter-frame correlation is larger than the threshold value. For this reason, the change of the residual transmission line distortion included in the received code Re after RAKE combining is determined by the adaptive equalizer 2.
When 00 is within the range that can be followed, adaptive equalization means is used. On the other hand, when it is determined that the change in the residual transmission path distortion is large, the received code Re after RAKE combining is directly subjected to error correction processing. Provided. For this reason, it is possible to prevent an erroneous equalization process from being performed in the adaptive equalizer 200 when the transmission path characteristics greatly change, thereby making it possible to perform a frequency distortion correction process using the adaptive equalizer 200. It can be performed stably.

The present invention is not limited to the above embodiment. For example, in the above-described embodiment, the case where all the circuits in the CDMA demodulation module are configured by hardware has been described as an example. However, each circuit of the module subsequent to the deinterleave unit has a DS
It can also be realized by software processing using a P (Digital Signal Processor) or a microprocessor.

In the above embodiment, a mobile communication terminal typified by a mobile phone has been described as an example.
The present invention is also applicable to a fixed installation type or on-vehicle type broadcast receiver for receiving a broadcast signal multiplexed by the M system. In addition, the configuration of each circuit in the CDMA demodulation module, the processing procedure, the processing content, and the like can be variously modified without departing from the scope of the present invention.

[0052]

As described in detail above, according to the present invention, a code error between a received code before error correction by an error correction unit and a received code after error correction is detected, and the detected code error is detected. By updating the tap coefficients of the adaptive equalizing means based on the updated tap coefficients, the equalization processing is performed on the received codes after the RAKE combining based on the updated tap coefficients, and the received codes after the equalization processing are erroneously processed. It is provided for correction processing.

Further, when operating the adaptive equalizing means, a time correlation of a frequency characteristic corresponding to the detected code error is obtained, and a residual included in a received code RAKE-combined based on the time correlation is obtained. It is determined whether or not the transmission line distortion is within a predetermined range. Then, only when it is determined that the residual transmission path distortion is within a predetermined range, the adaptive equalizing means updates the tap coefficients and performs equalization of the received code. The received code after the equalization is controlled to be input to the error correction unit.

Therefore, according to the present invention, not only the components of the phase distortion and the amplitude distortion but also the frequency distortion component can be corrected by operating the adaptive equalizing means effectively, whereby the error of the received code can be corrected. It is possible to provide a CDMA demodulation module capable of further reducing the rate and further improving the reception characteristics, and a wireless terminal device including the demodulation module.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram showing a configuration of a mobile communication terminal which is one embodiment of a wireless terminal device according to the present invention.

FIG. 2 is a CD provided in the mobile communication terminal shown in FIG.
FIG. 2 is a circuit block diagram illustrating a configuration of an MA demodulation module.

FIG. 3 is a circuit block diagram showing a configuration of a conventional CDMA demodulation module.

FIG. 4 is a signal waveform diagram for explaining a despreading operation in a finger.

FIG. 5 is a phase characteristic diagram for explaining an operation of estimating and correcting transmission line distortion in a transmission line estimating unit.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 antenna 2 antenna duplexer (DUP) 3 reception 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 Receiving amplifier 10 Speaker 11 Microphone 12 Control unit 13 Storage unit 14 Input unit 15 Display unit 16 Battery 17 Power supply circuit 18 Transmitting amplifier 111 to 11n Fingers 121 to 12n Timing adjustment unit 131 to 13n: transmission path estimating unit 140: RAKE combining unit 150, 185: deinterleaving unit 160, 210 ... error correcting unit 170: error detecting unit 180: equalization control unit 181 ... interleaving unit 182 ... frequency characteristic detecting unit 183 ... Correlation calculator 184 Memory 180 Switch switch 200 Adaptive equalizer

Claims (4)

[Claims] 1. A CDMA demodulation module for despreading reception signals corresponding to a plurality of paths by fingers, correcting transmission line distortion and performing RAKE synthesis, and correcting the synthesized reception code by an error correction unit. A code error detecting means for detecting a code error between a received code before error correction by the error correction unit and a received code after the error correction, and tapping based on the code error detected by the code error detecting means. An adaptive equalizer for updating a coefficient and performing equalization processing on the RAKE-combined received code based on the updated tap coefficient; and a frequency corresponding to a code error detected by the code error detector. A correlation detecting means for obtaining a characteristic and a time correlation of the frequency characteristic; and a time correlation obtained by the correlation detecting means.
Determining means for determining whether or not the residual transmission path distortion included in the RAKE-combined received code is within a predetermined range; and the determining means determines that the residual transmission path distortion is within a predetermined range. Control means for causing the adaptive equalizing means to update tap coefficients and equalize a received code, and to input the received code after the equalization to the error correction unit. A CDMA demodulation module. 2. The control means, when the determination means determines that the residual transmission path distortion exceeds a predetermined range, replaces the equalized output of the adaptive equalization means with the R signal.
2. The CDMA demodulation module according to claim 1, wherein the AKE-combined reception code is input to the error correction unit. 3. After receiving signals corresponding to a plurality of paths received by the radio section and inputting them to fingers, respectively, and despreading the signals, the transmission path estimating section corrects the transmission path distortion to obtain R
A wireless terminal device that performs AKE synthesis, corrects an error in the synthesized reception code in an error correction unit, and then reproduces information by a decoding processing unit. A code error detecting means for detecting a code error from the received code; and a tap coefficient updated based on the code error detected by the code error detecting means, and the updated tap for the RAKE-combined received code. Adaptive equalizing means for performing equalization processing based on coefficients; correlation detecting means for determining a frequency characteristic corresponding to the code error detected by the code error detecting means and calculating a time correlation of the frequency characteristic; Based on the time correlation obtained by the detection means,
Determining means for determining whether or not the residual transmission line distortion included in the RAKE-combined received code is within a predetermined range; and the determining means determines that the residual transmission line distortion is within a predetermined range. Control means for causing the adaptive equalizing means to update tap coefficients and equalize a received code, and to input the received code after the equalization to the error correction unit. A wireless terminal device characterized by the above-mentioned. 4. The control means, when the determination means determines that the residual transmission path distortion exceeds a predetermined range, replaces the equalized output of the adaptive equalization means with the R signal.
4. The wireless terminal device according to claim 3, wherein the received code subjected to AKE combining is input to the error correction unit.