WO2002019586A1

WO2002019586A1 - Cdma receiver and cdma receiving method

Info

Publication number: WO2002019586A1
Application number: PCT/JP2001/007403
Authority: WO
Inventors: Tadashi Yoshida; Daisuke Yamada
Original assignee: Matsushita Electric Industrial Co., Ltd.
Priority date: 2000-08-31
Filing date: 2001-08-29
Publication date: 2002-03-07
Also published as: AU2001282525A1; JP2002076990A

Abstract

A reception level measuring section (110) measures the reception level of a synchronous detection output. A weight determining section (111) calculates weight information on the basis of the reception level. An integrator (112) integrates an early correlation value with a predetermined time unit to determine an early integral and multiplies the early integral by the weight information outputted from the weight determining section (111). An integrator (113) integrates a late correlation value with a predetermined time unit to determine a late integral and multiplies the late integral by the weight information outputted from the weight determining section (111). A tracking judging section (114) compares the early integral with the late integral. If the early integral is larger than the late integral, the tracking judging section (114) outputs an instruction to delay a reception timing to a delay section; and if smaller, the tracking judging section (114) outputs an instruction to advance the reception timing to a delay section (103).

Description

Specification

CDMA receiver and CDMA receiving method

The present invention relates to a CDMA receiving apparatus and a CDMA receiving method, and more particularly to a despreading process in CDMA receiving. Background art

In CDMA wireless communication, despreading is performed by multiplying the received spread-spectrum modulated signal and the spread code in synchronization. The reception spread modulation signal may be shifted in reception timing due to the effects of fading or the like, and there is a so-called synchronization tracking as a method of correcting a shift in synchronization between the reception spread modulation signal and the spread code.

Conventionally, as a synchronization tracking method in a CDMA receiving apparatus and method, there is a method described in JP-A-10-173630 or the like.

The following describes synchronization tracking in a conventional CDMA receiver. FIG. 1 is a block diagram showing a configuration of a despreading unit in a conventional CDMA receiving apparatus. In an actual configuration, similar blocks are prepared for a plurality of paths. Here, an example in which processing is performed for one path will be described.

CDMA receiver shown in FIG. 1, a search unit 11, a spreading code replica onset producing unit 12, a delay unit 13, and the Shift register evening 14, a reference correlator 15, and Ea _r l _y correlator 16, Lat It mainly includes an e-correlator 17, a channel estimation unit 18, a channel fluctuation compensation unit 19, an integrator 20, an integrator 21, and a tracking determination unit 22.

In FIG. 1, search section 11: measures the reception timing of the spread modulation signal and outputs the result to delay section 13. The spreading code replica generation unit 12 -Generates a code and outputs it to the reference correlator 15, the early correlator 16, and the late correlator 17. The delay unit 13 delays the spread modulated signal converted into the digital value in accordance with the reception timing output from the search unit 11 and outputs the delayed signal to the shift register 14.

The shift register 14 outputs the spread modulation signal output from the delay unit 13 to the Ear 1 y correlator 16, delays this spread modulation signal for a fixed time, outputs the spread modulation signal to the reference correlator 15, The signal is delayed for a certain time and output to the late composer 17. For example, the shift register 14 outputs a spread modulation signal to the Early correlator 16, the reference correlator 15, and the Late correlator 17 at an M / N chip interval (M <N).

The reference correlator 15 despreads the spread modulation signal output from the shift register 14 with the spreading code replica code output from the spreading code replica generation unit 12, and obtains the obtained reference correlation value with the channel estimation unit 18 and channel fluctuation. Output to compensator 19.

The channel estimator 18 compares the reference correlation value with a predetermined pilot pattern to estimate a channel variation that is a variation in the amplitude or phase of the reference correlation value, and sends the estimated channel variation to the channel variation compensator 19. Output. Here, the channel fluctuation indicates the amplitude and phase fluctuation of a signal due to fading or the like. The channel fluctuation compensator 19 calculates channel fluctuation compensation information based on the channel fluctuation estimated value output from the channel estimator 18 and performs channel fluctuation compensation of the reference correlation value based on the channel fluctuation compensation information. Then, the reference correlation value is absolutely synchronously detected and demodulated.

The early correlator 16 performs inverse spreading on the spread modulation signal output from the shift register 14 using the spreading code replica code output from the spreading code reproducibility generator 12 and integrates the obtained early correlation value. Output to the container 20. The late correlator 17 adds a spread code replica to the spread modulated signal output from the shift register 14. Despreading is performed using the spreading code replica code output from the force generator 12, and the obtained Late correlation value is output to the integrator 21.

The integrator 20 integrates the Ear1y correlation value output from the Early correlator 16 in a predetermined time unit, and outputs the obtained Ear1y integrated value to the tracking determination unit 22. The integrator 21 integrates the late correlation value output from the late correlator 17 in a predetermined time unit, and outputs the obtained late integral value to the tracking determination unit 22.

The tracking determination unit 22 compares the value of the Early integral value with the value of the Late integral value. If the integrated value is smaller than the Late integrated value, an instruction to delay the reception timing is output to the delay unit 13.

Next, an example in which tracking determination is performed by adding a weight to the integral value will be described. FIG. 2A, FIG. 2B, FIG. 2C, and FIG. 2D are diagrams showing integrated values in conventional tracking determination. In FIG. 2A, FIG. 2B, FIG. 2C, and FIG. 2D, it is assumed that the received signals are backscattered in a synchronized state. In addition, the examples of FIGS. 2A, 2B, 2C, and 2D show a state where there is no influence of signal amplitude and phase fluctuation due to fading or the like.

FIG. 2A shows a reception level state where there is no influence of signal amplitude and phase fluctuation due to fading or the like.

The Early correlation value takes a constant value when the reception level does not change as shown in Fig. 2B. Similarly, the late correlation value takes a constant value when the reception level does not change as shown in Fig. 2C. The E ar 1 y correlation value and the L ate correlation value are multiplied by the weight information, and the results of the multiplication are added in reverse phase.

Figure 2D shows the result of the negative-phase addition of the Ear 1 y correlation value and the Late correlation value multiplied by the weight information. If there is no deviation in the synchronized state, the addition result indicates 0 as shown in FIG. 2D. However, an error may occur in the addition result due to the influence of the amplitude and phase fluctuation of the signal due to fading or the like. FIG. 3A, FIG. 3B, FIG. 3C, and FIG. 3D are diagrams showing integrated values in conventional tracking determination. 3A, 3B, 3C, and 3D, it is assumed that the received signal is despread in a synchronized state.

FIG. 3A shows the change in the reception level due to the influence of signal amplitude and phase fluctuation due to fading and the like. As described above, according to the CDMA receiving apparatus of the present embodiment, the Early correlation value is such that the integrated values of the portions B-4, B-5, and B-6 where the reception level has decreased as shown in FIG. 3B decrease. .

As for the late correlation value, as shown in FIG. 3C, the integral value increases for the portions C-1, C-5, and C-6 where the reception level has decreased. The E ar 1 y correlation value and the L ate correlation value are added in reverse phase.

Figure 3D shows the result of the negative-phase addition of the Early correlation value and the Late correlation value. The addition results D-4, D-5, and D-6 have negative addition results, and the CDMA receiver incorrectly determines that synchronization has been lost.

However, the conventional apparatus integrates the Ear 1 y correlation value and the Late correlation value that do not compensate for the channel fluctuation, and integrates the sections with large and small distortions with the same weight. including.

If the reception timing is adjusted using this integrated value, erroneous adjustment of the reception timing occurs, so that despreading is performed at an erroneous synchronization timing, resulting in a problem that the reception quality is significantly deteriorated. Disclosure of the invention

An object of the present invention is to provide a CDMA receiving apparatus and method capable of performing more accurate synchronization tracking in a despreading process of CDMA reception and obtaining a received signal of better quality. The purpose is to perform synchronization tracking by weighing the despread result used for synchronization tracking based on the reception quality information obtained from the reference despread result, i.e., despreading with low weighting when reception quality is poor. This is achieved by performing synchronization tracking using the results and reducing false synchronization tracking based on signals in unreliable sections. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a block diagram showing a configuration of a despreading unit in a conventional CDMA receiver, FIG. 2A is a diagram showing an integrated value in a conventional tracking determination,

FIG. 2B is a diagram showing an integrated value in a conventional tracking determination,

FIG. 2C is a diagram showing an integrated value in a conventional tracking determination,

FIG. 2D is a diagram showing an integrated value in a conventional tracking determination,

FIG. 3A is a diagram showing an integrated value in a conventional tracking determination,

FIG. 3B is a diagram showing an integrated value in a conventional tracking judgment,

FIG. 3C is a diagram showing an integrated value in a conventional tracking determination,

Figure 3D is a diagram showing the integrated value in the conventional tracking judgment,

FIG. 4 is a block diagram showing a configuration of a despreading unit of the CDMA receiving apparatus according to Embodiment 1 of the present invention.

FIG. 5 is a diagram showing an example of a conversion table used when creating weight information according to the above embodiment,

FIG. 6A is a diagram showing an integrated value in the tracking determination according to the above embodiment, FIG. 6B is a diagram showing an integrated value in the tracking determination according to the above embodiment, and FIG. 6C is a diagram showing the integrated value in the above embodiment. FIG. 6D is a diagram illustrating an integrated value in the tracking determination according to the embodiment, FIG. 6D is a diagram illustrating an integrated value in the tracking determination according to the embodiment, FIG. FIG. 7 shows an example of a configuration of a despreading unit of the CDMA receiving apparatus according to Embodiment 2. Block Diagram,

FIG. 8 is a diagram showing an example of a conversion table used when creating weight information according to the above embodiment,

FIG. 9 is a block diagram showing an example of a configuration of a despreading unit of the CDMA receiving apparatus according to Embodiment 3, and

FIG. 10 is a block diagram showing an example of the configuration of the despreading unit of the CDMA receiving apparatus according to Embodiment 4. BEST MODE FOR CARRYING OUT THE INVENTION

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

(Embodiment 1) ′ The CDMA receiving apparatus according to Embodiment 1 of the present invention performs synchronization tracking by weighting a despread result used for synchronization tracking based on received quality information obtained by despreading. FIG. 4 is a block diagram showing a configuration of a despreading unit of the CDMA receiving apparatus according to Embodiment 1 of the present invention.

In FIG. 4, CDMA receiving apparatus 100 includes search section 101, spreading code repetition force generating section 102, delay section 103, shift register 104, reference correlator 105, early correlator 106, late correlation Main unit 107, a channel estimation unit 108, a channel fluctuation compensation unit 109, a reception level measurement unit 110, a weight determination unit 111, an integrator 112, an integrator 113, and a tracking determination unit 114. It is composed of

Search section 101 detects an initial reception timing from the spread modulation signal and outputs the result to delay section 103.

Delay section 103 delays the spread modulation signal in accordance with the initial reception timing output from search section 101 and outputs the result to shift register 104. Further, delay section 103 performs spread modulation in accordance with the instruction output from tracking determination section 114. Make the signal output timing earlier or later.

The shift register 104 outputs the spread modulation signal output from the delay unit 103 to the early correlator 106, delays this spread modulation signal for a fixed time, and outputs it to the reference correlator 105. Is output to the Late correlator 107 after a certain time delay.

For example, it is assumed that the shift register 104 can output three signals delayed at MZN chip intervals. Here, if M21 and N = 2 are set, a total of three types of spread modulation signals, which are shifted from the standard reception timing by 0 chip, +1 no chip, and 11/2 chip, are obtained. Output.

Spreading code replica generating section 102 generates a spreading code replica code used for despreading and outputs it to reference correlator 105, early correlator 106, and late correlator 107.

The reference correlator 105 despreads the spread modulation signal output from the shift register 104 with the spreading code replica code output from the spreading code replica generation unit 102, and obtains a reference correlation value obtained by the channel estimation unit 108 Output to fluctuation compensation unit 109.

Early correlator 106 despreads the spread modulation signal output from shift register 104 with the spreading code replica code output from spreading code replica generating section 102, and outputs the obtained Early correlation value to integrator 112. Output.

The late correlator 107 despreads the spread modulated signal output from the shift register 104 with the spread code replica code output from the spread code replica generator 102, and converts the obtained late correlation value into an integrator 113. Output to

The channel estimating section 108 compares the reference correlation value output from the reference correlator 105 with a predetermined pilot pattern to estimate a channel variation value which is a distortion of the reference correlation value. The estimated value is output to channel fluctuation compensation section 109. Specifically, channel estimating section 108 calculates the phase rotation and amplitude fluctuation based on the difference between the predetermined pilot symbol pattern and the despread value output from reference correlator 105, and calculates the phase rotation and amplitude. The channel fluctuation of the despread value is estimated based on the fluctuation amount, and the estimated channel fluctuation value is output to channel fluctuation compensating section 109.

The channel fluctuation compensating unit 109 performs channel fluctuation compensation of the despread value output from the reference correlator 105 using the channel fluctuation estimated value output from the channel estimating unit 108, and outputs the synchronous detection result to the reception level measuring unit. Output to 110. For example, channel estimation and channel fluctuation compensation are performed by absolute synchronous detection, and the synchronous detection result is output to the reception level measuring unit 110.

Reception level measurement section 110 measures the reception level of the synchronous detection output, and outputs the result to weight determination section 111. The weight determination unit 111 calculates weight information for multiplying the Ear 1 y correlation value and the Late correlation based on the reception level output from the reception level measurement unit 110, and outputs the information to the integrator 112 and the integrator 113. .

The integrator 112 is output from the Early correlator 106: the Early correlation value is integrated in a predetermined time unit to obtain an Early integration value, and the Ear1y integration value is output from the weight determination unit 11 1 The calculated weight information is multiplied and output to the tracking determination unit 114.

The integrator 113 integrates the late correlation value output from the late correlator 107 in a predetermined time unit to obtain a late integral value, and outputs the late integral value to the weight determining unit 111. The weighting information is multiplied and output to the tracking determination unit 114.

For example, the integrator 112 and the integrator 113 perform in-phase addition of the Early correlation value or the Late correlation value with a pilot pattern for a predetermined number of symbols, multiply the result by weight information, and furthermore, The power addition is performed, and the obtained integrated value is output to the tracking determination unit 114. Also, the integrator 112 and the integrator As for 113, power addition may always be performed without performing in-phase addition.

The tracking determination unit 114 compares the Early integrated value output from the integrator 112 with the Late integrated value output from the integrator 113, and the Early integrated value is larger than the Late integrated value. In this case, an instruction to advance the reception timing is output to the delay unit. If the Early integration value is smaller than the Late integration value, an instruction to delay the reception timing is output to the delay unit 103.

Specifically, if the Early integral value is larger than the Late integral value, the reception timing is advanced by, for example, 1/4 chip, and conversely, if it is smaller, the reception timing is delayed by, for example, 1/4 chip, and new reception is performed. The timing is output to the delay unit 103. At this time, if the difference between the integral value on the Ear 1 y side and the integral value on the Late side is equal to or less than a predetermined value, the reception timing is not changed so that the reception timing does not erroneously change the timing due to slight distortion. .

Next, the signal flow of the CDMA receiver 10 ° will be described. However, for simplicity of explanation, attention is focused on one block, and processing for one spread modulation signal will be described.

The initial reception timing is obtained from the spread modulation signal received in search section 101 and output to delay section 103.

The spread modulation signal is output to the shift register 104 in synchronization with the timing earlier than the initial reception timing output from the search unit 101 in the delay unit 103 by a predetermined time, and is output to the early correlator 1◦6 in the shift register 104. The output is output to the reference correlator 105 with a certain time delay from the output time, and further output to the Late correlator 107 with a certain time delay from this output time.

The Early correlation value is obtained by correlating the spread modulation signal and the spread code replica in the Early correlator 106, and is output to the integrator 112. The late correlation value is calculated by the late correlator 10 、 It is obtained by correlating the replica and output to the integrator 113. The reference correlation value is obtained by correlating the spread modulation signal with the spreading code replica power in reference correlator 105, and is output to channel estimation section 108 and channel fluctuation compensation section 109.

The channel fluctuation estimation value is calculated based on the difference between the predetermined pilot symbol pattern in the channel estimation unit 108 and the inverse spread value output from the reference correlator 105, and is output to the channel fluctuation compensation unit 109. Is done.

The synchronous detection result of the reference correlation value is obtained by performing channel fluctuation compensation on the reference correlation value with the estimated channel fluctuation value in the channel fluctuation compensating section 109, and is output to the reception level measuring section 110.

The reception level of the synchronous detection output is calculated from the reference correlation value in the reception level measurement unit 110 and output to the weight determination unit 111. The weight information is determined based on the reception level output from the reception level measurement unit 110, and a synchronous detection output is output to the integrators 112 and 113.

The Early integration value is obtained by in-phase addition of the Ear 1 y correlation value by the predetermined number of symbols in the integrator 1 12 and multiplying the obtained power value by the weight determined by the weight determination unit 111. It is obtained by adding a plurality of times and output to the tracking determination unit 114.

For the late integral value, the integrator 113 adds the late correlation value in-phase for a predetermined number of symbols in-phase and adds the value obtained by multiplying the obtained power value by the weight determined by the weight determination unit 111 multiple times. And output to the tracking determination unit 114.

The instruction for changing the reception timing is obtained from the result obtained by comparing the integrated values of Early and Late in the tracking determination section 114 and is output to the delay section 103.

Next, an example in which weight information is created in the weight determination unit 111 using the conversion table will be described. FIG. 5 is a diagram showing an example of a conversion table used when creating weight information according to the first embodiment. The weight determining section 111 has a conversion table for converting into weight information. For example, as shown in FIG. 5, a conversion table for converting a reception level into a weight can be prepared in advance and determined.

For example, if the reception level is less than 10 dB, set the weight information to 0.05. If the reception level is greater than -1 OdB and less than 15 dB, set the weight information to 0.1. If the reception level is greater than -5 dB and less than OdB, set the weight information to 0.2.

Similarly, the weight information can be created by converting the reception level based on the conversion table. Also, the weight information can be set to 1 when the reception level is above a certain threshold, and to 0 when the reception level is below the threshold.

Next, an example in which a weighting is added to the integral value to perform the tracking determination will be described. 6A, FIG. 6B, FIG. 6C, FIG. 6D, and FIG. 6E are diagrams showing integral values in tracking determination according to the first embodiment. 6A, 6B, 6C, 6D, and 6E, it is assumed that the received signal is despread in a synchronized state.

FIG. 6A shows a change in the reception level due to the influence of signal amplitude and phase fluctuation due to fusing and the like. As described above, according to the CDMA receiving apparatus of the present embodiment, the Early correlation value decreases as shown in FIG. 6B, where the integrated values of the portions B-1, B-2, and B-3 where the reception level decreases are reduced. .

As for the Late correlation value, as shown in FIG. 6C, the integral value increases in the portions C-1, C-2, and C-3 where the reception level has decreased. The Ear 1 y correlation value and the L ate correlation value are multiplied by weight information, and the results of the multiplication are added in reverse phase. Fig. 6D shows an example of weight information. In Fig. 6A, the weights D-1, D-2, and D3 of the portion where the reception level is reduced due to the influence of the signal amplitude and phase fluctuation, etc. It will be a low value based on this.

Figure shows the result of negative-phase addition of the Ear 1 y correlation value and the Late correlation value multiplied by the weight information. Shown in 6E. Each of the addition results E-1, E-2, and E-3 has a small value, and no determination is made to change the reception timing.

As described above, according to the CDMA receiving apparatus of the present embodiment, the synchronization tracking is performed by weighting the despread result used for the synchronization tracking based on the reception quality information obtained by the despreading, so that fading or the like can be achieved. Even if the received signal is degraded due to the influence, the synchronization tracking can be performed more accurately, and the receiving performance can be improved.

In addition, by performing synchronization tracking by weighting the despread result used for synchronization tracking based on the reception level of the signal obtained by despreading, even if the received signal is deteriorated due to fusing, etc., more accurate In this case, synchronization tracking can be performed, and the reception performance can be improved.

(Embodiment 2)

The CDMA receiving apparatus according to the second embodiment of the present invention performs synchronization tracking by weighting a despread result used for synchronization tracking based on a desired signal-to-noise ratio of a signal obtained by despreading.

FIG. 7 is a block diagram showing an example of a configuration of a despreading unit of the CDMA receiving apparatus according to Embodiment 2. However, the same components as those in FIG. 4 are denoted by the same reference numerals as those in FIG. 4, and detailed description is omitted.

7 differs from FIG. 4 in that the CDMA receiving apparatus of FIG. 7 includes a reception SIR measuring unit 201 and obtains weight information from an SIR (Signal to Interference Ratio) ratio of a reception signal.

In FIG. 7, channel fluctuation compensating section 109 performs channel fluctuation compensation of the despread value output from reference correlator 105 using the estimated channel fluctuation value. For example, channel estimation and channel fluctuation compensation are performed by absolute synchronous detection, and the synchronous detection result is output to the reception SIR measurement unit 201 and outside.

The reception SIR measurement unit 201 calculates the SIR of the synchronous detection output for each predetermined signal section. Measure and output the SIR to weight determination section 202.

Weight determining section 202 determines weight information based on the SIR, and outputs it to integrator 112 and integrator 113. For example, weight determining section 202 sets the received SIR as it is as weight information. In addition, it is also possible to convert the received SIR into weight information using a conversion table and determine the weighted information. Also, the weight information can be set to 1 when the reception SIR is equal to or higher than a predetermined threshold, and set to 0 when the reception SIR is equal to or lower than the threshold.

The integrator 112 integrates the Ear 1 y correlation value output from the Earl y correlator 106 in a predetermined time unit into an Ear 1 y integrated value, and the weight information output from the weight determination unit 202. And outputs the obtained result to the tracking determination section 114 obtained.

The integrator 113 multiplies the late integration value obtained by integrating the late correlation value output from the late correlator 107 in a predetermined time unit by the weight information output from the weight determination unit 202. , And outputs the obtained tracking determination unit 114. Next, the signal flow of CDMA receiving apparatus 200 will be described. In the present embodiment, as in Embodiment 1, attention will be paid to one block, and processing for one spread modulation signal will be described. However, detailed description of the signal flow common to the first embodiment is omitted.

The reception level of the synchronous detection output is calculated from the reference correlation value in reception level measurement section 110 and output to reception SIR measurement section 201. The weight information is determined based on the SIR output from the received SIR measurement section 201, and a synchronous detection output is output to the integrator 112 and the integrator 113.

The Earl y integrated value is obtained by in-phase addition of the Ear 1 y correlation value for a predetermined number of symbols in the integrator 112, and adding a value obtained by multiplying the obtained power value by the weight determined by the weight determination unit 111 a plurality of times. This is output to the tracking determination unit 114.

The late integral value is a value obtained by adding the late correlation value in-phase for the predetermined number of symbols in the integrator 113 and adding the weight obtained by the weight determining unit 111 to the obtained power value. Are added a plurality of times and output to the tracking determination unit 114.

The instruction to change the reception timing is obtained from the result obtained by comparing the Ear 1 y integral value and the Late integral value in the tracking determination unit 114, and is output to the delay unit 103.

Next, an example will be described in which the weight determining unit 202 creates weight information from the SR using the conversion table. FIG. 8 is a diagram showing an example of a conversion table used when creating weight information according to the second embodiment.

The weight determining unit 202 has a conversion table that converts the S information into weight information. For example, as shown in FIG. 8, it is possible to prepare and determine in advance a conversion table for converting SER into weight information.

For example, if the SIR is less than 0.1, set the weight information to 0. If SIR is greater than 0.1 and less than or equal to 0.5, the weight information is set to 0.1. If the SIR is greater than 0.5 and less than or equal to 1, set the weight information to 0.3. Similarly, the weight information can be created by converting the reception level of the SIR according to the conversion table. Also, the weight information can be set to 1 when the reception level is above a certain threshold, and to 0 when the reception level is below the threshold.

Thus, according to the CDMA receiving apparatus of the present embodiment, synchronization tracking is performed by weighting the despread result used for synchronization tracking based on the desired signal-to-noise wave ratio of the signal obtained by despreading. As a result, even if the received signal deteriorates due to the effects of fading or the like, synchronization tracking can be performed more accurately, and the reception performance can be improved.

(Embodiment 3)

The CDMA receiving apparatus according to Embodiment 3 of the present invention performs compensation for channel fluctuation on the result of despreading used for synchronization tracking, and performs synchronization tracking by weighting based on the reception quality of a signal obtained by despreading.

FIG. 9 shows an example of the configuration of the despreading unit of the CDMA receiving apparatus according to Embodiment 3. It is a block diagram. However, the same components as those in FIG. 4 are denoted by the same reference numerals as those in FIG. 4, and detailed description is omitted.

9 differs from FIG. 4 in that the CDMA receiving apparatus of FIG. 9 includes a channel fluctuation compensating section 301 and a channel fluctuation compensating section 302 to compensate for channel fluctuations in the Early correlation value and the Late correlation value.

In FIG. 9, Eary correlator 106 outputs an E ar 1 y correlation value obtained by correlating the spread modulation signal and the spread code replay power to channel fluctuation compensating section 301.

The channel fluctuation compensator 301 performs channel fluctuation compensation of the Ear 1 y correlation value output from the early correlator 106 using the channel fluctuation estimated value output from the channel estimator 108, and performs channel fluctuation compensation. The obtained Ear 1 y correlation value is output to the integrator 112.

For example, the channel estimation section 108 performs channel estimation by absolute synchronous detection, the channel fluctuation compensation section 301 performs channel fluctuation compensation based on the channel estimation result, and outputs an Earl correlation value to the integrator 112.

The late correlator 107 outputs a late correlation value obtained by correlating the spread modulation signal and the spread code replica to the channel fluctuation compensation unit 302. The channel fluctuation compensating section 302 performs channel fluctuation compensation of the late correlation value output from the late correlator 107 by using the channel fluctuation estimated value output from the channel estimating section 108, and performs e The correlation value is output to the integrator 112.

For example, the channel estimation section 108 performs channel estimation by absolute synchronous detection, the channel fluctuation compensation section 302 performs channel fluctuation compensation based on the result of the channel estimation, and outputs the late correlation value to the integrator 113.

The integrator 112 integrates the Early correlation value output from the channel fluctuation compensating unit 301 in a predetermined time unit into an Ear1y integrated value, and the weight determining unit 202 Are multiplied by the weight information output from the controller and output to the obtained tracking determination unit 114.

The integrator 1 13 adds the late integration value obtained by integrating the late correlation value output from the channel fluctuation compensator 3 02 in a predetermined time unit to the weight output from the weight determiner 2 0 2 The information is multiplied and output to the obtained tracking determination section 114.

In practice, a plurality of processing blocks are connected in parallel for each multipath so as to be able to process a plurality of spread modulation signals having different reception timings by using a plurality of inverse spread sections of the present invention. The output is RAKE combined and decoded.

As described above, according to the CDMA receiving apparatus of the present embodiment, amplitude or phase fluctuation is compensated for the despread result used for synchronization tracking, and weighting is performed based on the reception quality of a signal obtained by despreading. By performing synchronization tracking, even when the received signal is degraded due to fading or the like, synchronization tracking can be performed more accurately, and reception performance can be improved.

(Embodiment 4)

The CDMA receiving apparatus according to Embodiment 4 of the present invention performs channel tracking compensation on the result of despreading used for synchronization tracking, and performs synchronization tracking by weighting based on the reception quality of a signal obtained by despreading.

FIG. 10 is a block diagram showing an example of a configuration of a despreading unit of the CDMA receiving apparatus according to Embodiment 4. However, the same components as those in FIG. 4 or FIG. 6 are denoted by the same reference numerals as those in FIG. 4 or FIG.

10 is different from FIG. 6 in that the CDMA receiving apparatus of FIG. 10 includes a reception SIR measuring section 401 and a weight determining section 402 and obtains weight information from the SIR ratio of a received signal. In FIG. 10, a channel fluctuation compensating unit 109 performs channel fluctuation compensation of the despread value output from the reference correlator 105 using the channel fluctuation estimated value. For example, channel estimation and channel fluctuation compensation are performed by absolute synchronous detection, and synchronous detection is performed. Outputs the result to the SIR measurement section 401 and externally.

The reception SIR measurement section 401 measures the SIR of the synchronous detection output for each predetermined signal section, and outputs the SIR to the weight determination section 402.

The weight determining unit 402 determines the weight information based on S I I, and outputs the weight information to the integrators 112 and 113. For example, the weight determining section 402 sets the received SIR as it is as the weight information. Further, it is also possible to convert the received SIR into weight information using a conversion table and determine the weighted information. Also, the weight information can be set to 1 when the received SIR is equal to or larger than a predetermined threshold, and set to 0 when the received SIR is equal to or smaller than the threshold.

The integrator 1 1 2 integrates the Ear 1 y correlation value output from the Early correlator 106 with a predetermined time unit into the Ear 1 y integrated value, Are multiplied by the output weight information and output to the obtained tracking determination section 114.

The integrator 113 outputs the late integrated value obtained by integrating the late correlation value output from the late correlator 107 in a predetermined time unit, and outputs the integrated value to the weight determining unit 402. The weighting information is multiplied and output to the obtained tracking determination unit 114. As described above, according to the CDMA receiving apparatus of the present embodiment, channel fluctuation is compensated for the result of despreading used for synchronization tracking, and weighting is performed based on a desired signal to noise wave ratio of a signal obtained by despreading. By performing synchronization tracking, even when the received signal is degraded due to the influence of fusing or the like, synchronization tracking can be performed more accurately, and the reception performance can be improved.

The CDMA receiving apparatus of the present invention applies a weight to the integral value in a predetermined time unit, but the time unit is not particularly limited. For example, it is also possible to calculate the weight for the integral value for each slot and apply a weight to the integral value. As apparent from the above description, according to the present invention, the despread result used for synchronization tracking is weighted based on the reception quality information obtained from the reference despread result. By performing synchronization tracking, that is, when reception quality is poor, synchronization tracking is performed using the despread result with a small weight, and false synchronization tracking is reduced based on signals in sections with low reliability. In the despreading process of the reception of the CDMA system, more accurate synchronization tracking can be performed, and a reception signal of better quality can be obtained.

This description is based on Japanese Patent Application No. 2000-264200 filed on Aug. 31, 2000. This content is included here. Industrial applicability

INDUSTRIAL APPLICABILITY The present invention is applied to a radio receiving apparatus, and is particularly suitable for use in a CDMA communication type radio receiving apparatus.

Claims

The scope of the claims

1. Despreading means for despreading the spread signal at a predetermined reception timing to output a reference despread value, weight determining means for determining a weight based on the reception quality of the reference despread value, and the reception timing A first calculating means for despreading the spread signal at an earlier timing, and then outputting a first correlation value obtained by multiplying the despread result by the weight, and applying a first correlation value to the spread signal at a timing later than the reception timing. After performing despreading, a second calculating means for outputting a second correlation value obtained by multiplying the despread result by the weight, and receiving the data based on a comparison result between the first correlation value and the second correlation value. And a changing means for changing the setting.

2. The CDMA receiving apparatus according to claim 1, wherein the weight determining means determines the weight smaller as the reception quality of the reference despread value is lower.

3. The first arithmetic means multiplies a value obtained by adding a predetermined number of despread results by a weight, and the second arithmetic means multiplies the value obtained by adding a predetermined number of despread results by a weight. 2. The CDMA receiver according to item 1.

4. The CDMA receiving apparatus according to claim 1, wherein the weight determining means determines the weight based on the reception level of the reference despread value.

5. The CDMA receiving apparatus according to claim 4, wherein the weight determining means determines the weight based on a table that associates the reception level of the reference despread value with the weight. '

6.Channel fluctuation estimating means for estimating the fluctuation of the amplitude or phase of the reference despread value; and compensating means for compensating for the fluctuation of the amplitude or phase of the reference despread value based on the estimation result of the channel fluctuation estimating means. The CDMA receiving apparatus according to claim 1, further comprising: a weight determining unit that determines a weight based on a reception level of the reference despread value that compensates for amplitude or phase fluctuation.

7. The CDMA receiving apparatus according to claim 6, wherein the weight determining means determines the weight based on a table that associates the reception level of the reference despread value with the weight.

8. Channel fluctuation estimating means for estimating the amplitude or phase fluctuation of the reference despread value; And compensating means for compensating for the fluctuation of the amplitude or phase of the reference despread value based on the estimation result of the channel fluctuation estimating means.The weight determining means comprises: 2. The CDMA receiving apparatus according to claim 1, wherein the weight is determined based on a desired signal to interference wave ratio of the spread value.

9. The CDMA receiving apparatus according to claim 8, wherein the weight determining means determines the weight based on a template that associates the weight with the desired wave-to-interference wave ratio of the reference despread value.

10. First channel compensation means for compensating the amplitude or phase of the first correlation calculation result based on the estimation result of the channel variation estimation means, and second correlation calculation result based on the estimation result of the channel variation estimation means. And a second channel compensating means for compensating for amplitude or phase. The first computing means multiplies the first correlation computation result, for which the amplitude or phase compensation has been performed in the first channel compensating means, by a weight. The CDMA according to claim 6, wherein the second arithmetic unit multiplies the second correlation operation result, for which the amplitude or phase is compensated in the second channel compensation unit, by a weight. Receiver.

11. A base station device including a CDMA receiving device, wherein the CDMA receiving device despreads a spread signal at a predetermined reception timing and outputs a reference despread value. A weight determining means for determining a weight based on the reception quality of the reference despread value, and after performing despreading on the spread signal at a timing earlier than the reception timing, first despreading result is multiplied by the weight. First calculating means for outputting a correlation value, and second calculating means for despreading the spread signal at a timing later than the reception timing, and then outputting a second correlation value obtained by multiplying the despread result by the weight. Changing means for changing the reception timing based on a comparison result between the first correlation value and the second correlation value.

12. A communication terminal device including a CDMA receiving device, wherein the CDMA receiving device despreads a spread signal at a predetermined reception timing and outputs a reference despread value. Despreading means, weight determining means for determining a weight based on the reception quality of the reference despread value, despreading the spread signal at a timing earlier than the reception timing, and First calculating means for outputting a first correlation value multiplied by the weight, second despreading the spread signal at a timing later than the reception timing, and then multiplying a despread result by the weight. A second calculating means for outputting a correlation value; and changing means for changing the reception timing based on a comparison result between the first correlation value and the second correlation value.

13. A despreading step of despreading the spread signal at a predetermined reception timing to output a reference despread value, a weight determining step of determining a weight based on the reception quality of the reference despread value, After performing despreading on the spread signal at a timing earlier than evening timing, a first calculation step of outputting a first correlation value obtained by multiplying the despread result by the weight, After performing despreading, a second operation step of outputting a second correlation value obtained by multiplying the despread result by the weight, and the reception time based on a comparison result between the first correlation value and the second correlation value. And a changing step of changing the ringing.