JP2002076990A - Cdma receiving device and method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To carry out synchronous tracking of high accuracy so as to obtain receiving signals of high quality. SOLUTION: A receiving level measurement section 110 measures the receiving level of a synchronous detection output. A weighting decision section 111 calculates weight information based on the receiving level. An integrator 112 integrates an early correlation value by a prescribed time unit to obtain an early integral, and the early integral is multiplied by weight information outputted from the weight decision section 111. An integrator 113 integrates a late correlation value by a prescribed time unit to obtain a late integral, and the late integral is multiplied by weight information outputted from the weight decision section 111. A tracking judgment section 114 compares the early integral with the late integral. When it is found that the early integral is larger than the late integral, an instruction to delay receiving timing is outputted to a delay section 103. When it is found that the early integral is smaller than the late integral, an instruction to hasten receiving timing is outputted to the delay section 103.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a CDMA receiving apparatus and a CDMA receiving method, and more particularly to a despreading process in CDMA receiving.

[0002]

2. Description of the Related Art In CDMA wireless communication, despreading is performed by synchronizing and multiplying a received spread modulated signal and a spread code. 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 Japanese Patent Application Laid-Open No. 10-173630 or the like.

Hereinafter, synchronization tracking in a conventional CDMA receiving apparatus will be described. FIG. 8 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.

[0005] The CDMA receiver shown in FIG. 8 includes a search unit 11, a spread code replica generation unit 12, and a delay unit 1.
3, a shift register 14, a reference correlator 15, and Ea
rly correlator 16, Late correlator 17, channel estimator 18, channel fluctuation compensator 19, integrator 20
, An integrator 21 and a tracking determination unit 22.

[0006] In FIG. 8, search section 11 measures the reception timing of the spread modulation signal and outputs it to delay section 13. The spreading code replica generator 12 generates a spreading code replica code, and outputs the reference correlator 15 and the early correlator 1.
6. Output to 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 Early correlator 16, delays the spread modulation signal for a predetermined time, and outputs it to the reference correlator 15. The modulated signal is delayed for a fixed time and output to the late correlator 17. For example,
The shift register 14 converts the spread modulation signal into an early correlator 16 and a reference correlator 1 at M / N chip intervals (M <N).
5 to the Late correlator 17.

The reference correlator 15 converts the spread modulation signal output from the shift register 14 into a spread code replica generator 1.
2 is despread with the spreading code replica code output from
The obtained reference correlation value is output to channel estimation section 18 and channel fluctuation compensation section 19.

A channel estimator 18 compares a reference correlation value with a predetermined pilot pattern to estimate channel fluctuation, which is a change in amplitude or phase of the reference correlation value.
This channel fluctuation estimation value is output to channel fluctuation compensating section 19. Here, the channel fluctuation indicates a signal amplitude and phase fluctuation caused by fading or the like.

A 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 a reference correlation value based on the channel fluctuation compensation information. After that, the reference correlation value is subjected to absolute synchronous detection and demodulation.

The early correlator 16 despreads the spread modulation signal output from the shift register 14 with the spreading code replica code output from the spreading code replica generator 12 and converts the obtained early correlation value into an integrator 20. Output to The late correlator 17 adds the spread code replica generator 1 to the spread modulation signal output from the shift register 14.
Despreading is performed with the spreading code replica code output from 2, and the obtained Late correlation value is output to the integrator 21.

An integrator 20 integrates the Early correlation value output from the Early correlator 16 in a predetermined time unit, and obtains the obtained Early integrated value in the tracking determination unit 2.
Output to 2. The integrator 21 integrates the Late correlation value output from the Late correlator 17 in a predetermined time unit,
The obtained Late integral value is output to the tracking determination unit 22.

The tracking determination section 22 compares the Early integration value with the Late integration value, and outputs an instruction to delay the reception timing to the delay section if the Early integration value is larger than the Late integration value, and outputs the Early integration value. L
If the value is smaller than the ate integration value, an instruction to advance 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. 9 is a diagram showing an integrated value in the conventional tracking judgment. In FIG. 9, it is assumed that a received signal is despread in a synchronized state. FIG.
In the example, there is shown a state in which there is no influence of amplitude and phase fluctuation of a signal due to fading or the like.

FIG. 9A shows a state of the reception level which is not affected by the amplitude and phase fluctuations of the signal 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. 9B. Similarly, the Late correlation value takes a constant value when the reception level does not change as shown in FIG. 9C. The Early correlation value and the Late correlation value are multiplied by weight information, and the respective multiplication results are subjected to negative-phase addition.

The early correlation value multiplied by the weight information and L
FIG. 9D shows the result of the negative-phase addition of the ate correlation values. If there is no deviation in the synchronized state, the addition result indicates 0 as shown in FIG.

However, an error may occur in the addition result due to the influence of signal amplitude and phase fluctuation due to fading or the like.

FIG. 10 is a diagram showing an integrated value in the conventional tracking judgment. In FIG. 10, it is assumed that a received signal is despread in a synchronized state.

FIG. 10A shows a change in the reception level due to the influence of the amplitude and phase fluctuation of the signal due to fading or the like. As described above, according to the CDMA receiving apparatus of the present embodiment, the early correlation values indicate the portions B-4, B-5, and B- where the reception level has decreased as shown in FIG.
For 6 the integral decreases.

The Late correlation value is calculated by comparing the portions C-4, C-5 and C-5 where the reception level is reduced as shown in FIG.
The integral increases for -6. The Early correlation value and the Late correlation value are added in reverse phase.

FIG. 3D shows the result of the reverse phase addition of the Early correlation value and the Late correlation value. Addition result D-4, D-5
And D-6, the addition result becomes a negative value, and the CDMA receiving apparatus erroneously determines that the synchronization has shifted.

[0024]

However, in the conventional device, the Early which does not compensate for the channel fluctuation is used.
Since the correlation value and the Late correlation value are integrated, and the sections having a large distortion and the sections having a small distortion are integrated with the same weight, the integration value includes a large error.

If the reception timing is adjusted using this integrated value, the reception timing is erroneously adjusted, so that there is a problem that despreading is performed at an incorrect synchronization timing and the reception quality is significantly deteriorated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above point, and a CDMA receiving apparatus and a CDMA receiving apparatus capable of performing more accurate synchronization tracking in a despreading process of CDMA reception and obtaining a better quality reception signal. The aim is to provide a method.

[0027]

A CDMA receiver according to the present invention comprises a despreading means for despreading a spread signal at a predetermined reception timing and outputting a reference despread value, and a receiving quality of the reference despread value. Weight determining means for determining a weight based on the first and second calculating means for despreading the spread signal at a timing earlier than the reception timing, and then outputting a first correlation value obtained by multiplying the despread result by the weight. After performing despreading on the spread signal at a timing later than the reception timing, a second calculating means for outputting a second correlation value obtained by multiplying the despread result by the weight, and the first correlation value and the second Changing means for changing the reception timing based on the result of comparison with the correlation value.

The CDMA receiving apparatus of the present invention employs a configuration in which the weight determining means determines a smaller weight as the reception quality of the reference despread value is poor.

According to these configurations, 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 the reception signal is deteriorated due to the influence of fading or the like. However, synchronization tracking can be performed more accurately, and the reception performance can be improved.

In the CDMA receiver according to the present invention, the first arithmetic means multiplies a value obtained by adding a predetermined number of despread results by a weight, and the second arithmetic means adds a predetermined number of despread results. The value is multiplied by a weight.

The CDMA receiving apparatus of the present invention employs a configuration in which the weight determining means determines the weight based on the reception level of the reference despread value.

According to these configurations, the synchronization tracking is performed by weighting the result of despreading used for synchronization tracking based on the reception level of the signal obtained by the despreading. Even if
Synchronous tracking can be performed more accurately, and reception performance can be improved.

A CDMA receiving apparatus according to the present invention comprises: a channel fluctuation estimating means for estimating a fluctuation of the amplitude or phase of a reference despread value; and an amplitude or phase of the reference despread value based on the estimation result of the channel fluctuation estimating means. And a compensating means for compensating for the fluctuation, wherein the weight determining means determines the weight based on the reception level of the reference despread value which compensated for the fluctuation of the amplitude or phase.

[0034] The CDMA receiving apparatus of the present invention employs a configuration in which the weight determining means determines the weight based on a table that associates the reception level of the reference despread value with the weight.

According to these configurations, 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, so that reception is affected by fading and the like. Even when the signal has deteriorated, synchronization tracking can be performed more accurately, and the reception performance can be improved.

A CDMA receiving apparatus according to the present invention comprises: a channel fluctuation estimating means for estimating a fluctuation of the amplitude or phase of a reference despread value; and an amplitude or phase of the reference despread value based on the estimation result of the channel fluctuation estimating means. And a compensating means for compensating for the fluctuation, wherein the weight determining means determines the weight based on a desired-to-interference-wave ratio of the reference despread value for which the fluctuation of the amplitude or the phase has been compensated.

The CDMA receiving apparatus according to the present invention employs a configuration in which the weight determining means determines the weight based on a table that associates the desired wave-to-interference wave ratio of the reference despread value with the weight.

According to these configurations, the synchronization tracking is performed by weighting the result of despreading used for synchronization tracking based on the desired signal-to-noise ratio of the signal obtained by despreading. Even when the signal has deteriorated, synchronization tracking can be performed more accurately, and the reception performance can be improved.

The CDMA receiving apparatus according to the present invention comprises a first channel compensating means for compensating the amplitude or phase of the first correlation operation result based on the estimation result of the channel fluctuation estimating means, and a CDMA receiving apparatus based on the estimation result of the channel fluctuation estimating means. And a second channel compensating means for compensating for the amplitude or phase of the second correlation operation result. The calculation result is multiplied by a weight, and the second calculation means multiplies the weight by the second correlation calculation result whose amplitude or phase is compensated by the second channel compensation means.

According to this configuration, amplitude or phase fluctuations are compensated for the result of despreading used for synchronous tracking, and weighting is performed based on the reception quality of the signal obtained by despreading to perform synchronous tracking, thereby fading. Even if the received signal is degraded due to the influence of the above, the synchronization tracking can be performed more accurately, and the reception performance can be improved.

[0041] A base station apparatus according to the present invention employs a configuration including any of the CDMA receivers described above. A communication terminal device according to the present invention employs a configuration including any of the CDMA receiving devices described above.

According to this configuration, the synchronization tracking is performed by weighting the despread result used for synchronization tracking based on the reception quality information obtained by the despreading, so that even if the received signal is deteriorated due to the influence of fading or the like. Thus, the synchronization tracking can be performed more accurately, and the reception performance can be improved.

In the CDMA receiving method of the present invention, a despreading step of despreading a spread signal at a predetermined reception timing and outputting a reference despread value, and determining a weight based on the reception quality of the reference despread value. A weight determining step, a first calculating step of despreading the spread signal at a timing earlier than the reception timing, and then outputting a first correlation value obtained by multiplying the despread result by the weight, and a delay after the reception timing After performing despreading on the spread signal at the timing, a second operation step of outputting a second correlation value obtained by multiplying the despread result by the weight, and a comparison result of the first correlation value and the second correlation value A changing step of changing the reception timing based on
Was provided.

According to this method, 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 even if the received signal is deteriorated due to the influence of fading or the like. Thus, the synchronization tracking can be performed more accurately, and the reception performance can be improved.

[0045]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The gist of the present invention is to perform synchronization tracking by weighting a despread result used for synchronization tracking based on reception quality information obtained from a reference despread result.

That is, the gist of the present invention is that, when the reception quality is poor, by performing synchronization tracking using the despread result with a small weight, erroneous synchronization tracking based on a signal in a section with low reliability is performed. It is to reduce.

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

(Embodiment 1) A 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 reception quality information obtained by despreading.

FIG. 1 shows a CD according to the first embodiment of the present invention.
FIG. 4 is a block diagram illustrating a configuration of a despreading unit of the MA receiving device.

In FIG. 1, CDMA receiving apparatus 100 includes:
A search unit 101, a spreading code replica generation unit 102,
Delay section 103, shift register 104, reference correlator 105, early correlator 106, late correlator 107, channel estimation section 108, channel fluctuation compensation section 109, reception level measurement section 110, weight determination Part 1
11, an integrator 112, an integrator 113, and a tracking determination unit 114.

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

[0052] 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 advances or delays the output timing of the spread modulation signal according to the instruction output from tracking determination section 114.

The shift register 104 outputs the spread modulation signal output from the delay section 103 to the Early correlator 106, delays this spread modulation signal for a predetermined time, and outputs it to the reference correlator 105. The signal is delayed for a fixed time and output to Late correlator 107.

For example, the shift register 104 has an M / N
It is assumed that three signals delayed by the chip interval can be output. Here, when M = 1 and N = 2, a total of three types of spread modulation signals are output which are shifted by 0 chip, +1/2 chip and -1/2 chip with respect to the reference reception timing.

The spreading code replica generator 102 generates a spreading code replica code used for despreading, and generates a reference correlator 105, an early correlator 106, and a late correlator 10.
7 is output.

The reference correlator 105 is connected to the shift register 10
4 is despread with the spreading code replica code output from the spreading code replica generation unit 102, and the reference correlation value obtained is output to the channel estimation unit 108 and the channel fluctuation compensation unit 109.

The early correlator 106 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 early correlation value into the integrator 1.
12 is output.

The late correlator 107 performs despreading on 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 receives the reference correlator 10
The reference correlation value output from step 5 is compared with a predetermined pilot pattern to estimate a channel variation value, which is a distortion of the reference correlation value, and outputs the estimated channel variation value to channel variation compensating section 109.

More specifically, channel estimating section 108 calculates the phase rotation and amplitude variation based on the difference between a predetermined pilot symbol pattern and the despread value output from reference correlator 105, and calculates the phase rotation. And the channel fluctuation of the despread value is estimated based on the amplitude fluctuation amount and outputs the estimated channel fluctuation value to the channel fluctuation compensating section 109.

Channel fluctuation compensating section 109 performs channel fluctuation compensation of the despread value output from reference correlator 105 using the channel fluctuation estimated value output from channel estimating section 108, and outputs the synchronous detection result to the reception level. Measuring unit 1
Output to 10 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 measurement unit 110.

Receiving level measuring section 110 measures the receiving level of the synchronous detection output and outputs it to weight determining section 111.
The weight determination unit 111 determines the Early correlation value and La based on the reception level output from the reception level measurement unit 110.
Weight information for multiplying the te correlation is calculated and output to the integrators 112 and 113.

The integrator 112 is connected to the early correlator 106
Are integrated in a predetermined time unit to obtain an Early integrated value. The Early integrated value is multiplied by the weight information output from the weight determining unit 111 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 adds the weight information output from the weight determining unit 111 to the late integral value. The result is multiplied and output to the tracking determination unit 114.

For example, the integrator 112 and the integrator 113
Performs an in-phase addition of an Early correlation value or a Late correlation value for a predetermined number of symbols with a pilot pattern, multiplies the result by weight information, further performs power addition for a plurality of blocks, and tracks the obtained integrated value. Judgment unit 11
4 is output. Further, the integrator 112 and the integrator 113
May always perform power addition without performing in-phase addition.

The tracking determination section 114 is provided with the integrator 11
2 is compared with the value of the Late integrated value output from the integrator 113, and the Early integrated value is compared with the Early integrated value.
When the integrated value is larger than the Late integral value, an instruction to delay the reception timing is output to the delay unit, and when the Early integrated value is smaller than the Late integrated value, an instruction to advance the reception timing is output to the delay unit 103.

More specifically, when the Early integration value is
If it is larger than the integral value, the reception timing is set to, for example, 1 /
If the timing is smaller by four chips, and conversely, if the reception timing is smaller by, for example, １ ／ chip, the reception timing is set to a new reception timing and output to the delay unit 103. At this time, if the difference between the Early-side integral value and the Late-side integral value is equal to or less than a predetermined value so that the reception timing is not erroneously changed due to slight distortion, the reception timing is not changed.

Next, the flow of signals in CDMA receiving apparatus 100 will be described. However, to make the explanation easier to understand,
Focusing on one block, processing for one spread modulation signal will be described.

The initial reception timing is obtained from the spread modulation signal received by search section 101,
3 is output.

The spread modulation signal is supplied to the shift register 10 by the delay section 103 in accordance with a timing earlier than the initial reception timing output from the search section 101 by a predetermined time.
4 and the shift register 104 outputs
ly correlator 106, is output to the reference correlator 105 after a certain time delay from this output time,
It is output to Late correlator 107 with a certain delay from this output time.

The Early correlation value is calculated using the Early Correlator 1
At 06, it is obtained by correlating the spread modulation signal with the spread code replica and output to the integrator 112. The late correlation value is obtained by taking a correlation between the spread modulation signal and the spread code replica in the late correlator 107, and is output to the integrator 113.

The reference correlation value is obtained by correlating the spread modulation signal with the spread code replica in reference correlator 105, and output to channel estimation section 108 and channel fluctuation compensation section 109.

The channel fluctuation estimation value is calculated by the channel estimation unit 1
At 08, the calculated value is calculated based on the difference between the predetermined pilot symbol pattern and the despread value output from reference correlator 105, and is output to channel fluctuation compensation section 109.

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 channel fluctuation compensating section 109 and output to reception level measuring section 110.

The reception level of the synchronous detection output is calculated from the reference correlation value in reception level measuring section 110 and output to weight determining section 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 in-phase-added by the predetermined number of symbols to the Early correlation value in the integrator 112.
The value obtained by multiplying the obtained power value by the weight determined by the weight determination unit 111 is added a plurality of times.
4 is output.

The Late integration value is obtained by in-phase addition of the Late correlation value by a predetermined number of symbols in the integrator 113, 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. Is output to the tracking determination unit 114.

The instruction to change the reception timing is obtained from the result obtained by comparing the Early integration value and the Late integration value in the tracking determination section 114, and
3 is output.

Next, an example will be described in which the weight determining section 111 creates weight information using a conversion table. FIG. 2 is a diagram illustrating 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. 2, a conversion table for converting a reception level into a weight can be prepared in advance and determined.

For example, when the reception level is smaller than -10 dB, the weight information is set to 0.05. If the reception level is higher than −10 dB and lower than −5 dB, the weight information is set to 0.1. If the reception level is higher than −5 dB and equal to or lower than 0 dB, the weight information is set to 0.2.

Similarly, the weight information can be created by converting the reception level based on the conversion table.

Further, the weight information can be set to 1 when the reception level is equal to or higher than a certain threshold, and set to 0 when the reception level is equal to or lower than the threshold.

Next, an example in which tracking determination is performed by adding a weight to the integral value will be described. FIG. 3 is a diagram illustrating an integrated value in the tracking determination according to the first embodiment. In FIG. 3, it is assumed that a received signal is despread in a synchronized state.

FIG. 3A shows a change in the reception level due to the influence of the amplitude and phase fluctuation of the signal due to fading or 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-1, B-2, and B-3 where the reception level has decreased as shown in FIG. Decrease.

The Late correlation value is calculated by comparing the parts C-1, C-2 and C-C in which the reception level is reduced as shown in FIG.
For 3 the integral increases. The Early correlation value and the Late correlation value are multiplied by weight information, and the respective multiplication results are subjected to negative-phase addition.

FIG. 3D shows an example of the weight information.
In (a), the weights D-1, D-2, and D3 of the portions where the reception level is reduced due to the influence of the amplitude and phase of the signal are low based on the reception level.

The Early correlation value multiplied by the weight information and L
FIG. 3E shows the result of the negative phase addition of the ate correlation value. 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 synchronization tracking based on the reception quality information obtained by the despreading, thereby fading. Therefore, even when the received signal is degraded due to the influence of, the synchronization tracking can be performed more accurately, and the receiving performance can be improved.

Further, by performing synchronization tracking by weighting the result of despreading used for synchronization tracking based on the reception level of the signal obtained by despreading, even if the received signal is degraded due to the effects of fading or the like, more accurate detection can be achieved. , Synchronization tracking can be performed, and the reception performance can be improved.

(Embodiment 2) A CDMA receiving apparatus according to Embodiment 2 of the present invention synchronizes by weighting a despread result used for synchronization tracking based on a desired signal to noise wave ratio of a signal obtained by despreading. Perform tracking.

FIG. 4 is a block diagram showing an example of the configuration of the despreading unit of the CDMA receiving apparatus according to the second embodiment. However, the same components as those in FIG. 1 are denoted by the same reference numerals as those in FIG. 1, and the detailed description is omitted.

The CDMA receiving apparatus shown in FIG. 4 includes a reception SIR measuring section 201, and performs SIR (Signal to
The point that weight information is obtained from the ratio
Different from FIG.

In FIG. 4, channel fluctuation compensating section 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 the synchronous detection result is output to the reception SIR measurement unit 201 and outside.

The reception SIR measurement section 201 measures the SIR of the synchronous detection output for each predetermined signal section, and outputs the SIR to the weight determination section 202.

The weight determining section 202 determines weight information based on the SIR and outputs the weight information to the integrators 112 and 113. For example, the weight determination unit 202 uses the received SIR as it is as weight information. Further, it is also possible to convert the received SIR into weight information using a conversion table and determine the weight information.
When the reception SIR is equal to or greater than a predetermined threshold, the weight information is set to 1,
Below the threshold value, it can be set to 0.

The integrator 112 is connected to the early correlator 106
Are multiplied by the early integration value obtained by integrating the Early correlation value output from the unit in a predetermined time unit and the weight information output from the weight determination unit 202, and output to the tracking determination unit 114 obtained.

The integrator 113 multiplies the Late integrated 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 determining unit 202, Output to the obtained tracking determination unit 114.

Next, the signal flow of CDMA receiving apparatus 200 will be described. Similar to Embodiment 1, this embodiment focuses on one block and describes processing for one spread modulation signal. However, a detailed description of the signal flow common to the first embodiment will be omitted.

The reception level of the synchronous detection output is calculated from the reference correlation value in the reception level measurement section 110, and the reception level is calculated.
Output to IR measuring section 201.

The weight information is determined based on the SIR output from the reception SIR measuring section 201, and the synchronous detection output is output to the integrators 112 and 113.

The Early integration value is in-phase-added by the predetermined number of symbols to the Early correlation value in the integrator 112.
The value obtained by multiplying the obtained power value by the weight determined by the weight determination unit 111 is added a plurality of times.
4 is output.

The late integral value is obtained by in-phase addition of the late correlation value by a predetermined number of symbols in the integrator 113, and adding a value obtained by multiplying the obtained power value by the weight determined by the weight determining unit 111 a plurality of times. Is output to the tracking determination unit 114. The instruction to change the reception timing is obtained from the result obtained by comparing the Early integration value and the Late integration value in the tracking determination section 114, and
3 is output.

Next, an example will be described in which the weight determining section 202 creates weight information from SIR using a conversion table.
FIG. 5 is a diagram showing an example of a conversion table used when creating weight information according to the second embodiment.

The weight determining section 202 has a conversion table for converting the SIR into the weight information using the SIR information, and prepares a conversion table for converting the SIR into the weight information in advance as shown in FIG. Can be determined.

For example, when the SIR is smaller than 0.1, the weight information is set to 0. If the 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, the weight information is set to 0.3.

Similarly, the weight information can be created by converting the SIR into a reception level according to a conversion table.

The weight information may be set to 1 when the reception level is equal to or higher than a certain threshold, and may be set to 0 when the reception level is equal to or lower than the threshold.

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

(Embodiment 3) A CDMA receiving apparatus according to Embodiment 3 of the present invention compensates for channel fluctuation in the result of despreading used for synchronization tracking and weights based on the reception quality of a signal obtained by despreading. And perform synchronization tracking.

FIG. 6 is a block diagram showing an example of the configuration of the despreading unit of the CDMA receiving apparatus according to the third embodiment. However, the same components as those in FIG. 1 are denoted by the same reference numerals as those in FIG. 1, and the detailed description is omitted.

The CDMA receiving apparatus shown in FIG. 6 includes a channel fluctuation compensating section 301 and a channel fluctuation compensating section 302 and
The difference from FIG. 1 is that the channel correlation is compensated for the early correlation value and the late correlation value.

In FIG. 6, Early correlator 106
Outputs an early correlation value obtained by correlating the spread modulation signal with the spread code replica to the channel fluctuation compensation unit 301.

Channel fluctuation compensating section 301 performs channel fluctuation compensation of the early correlation value output from early correlator 106 using the channel fluctuation estimated value output from channel estimating section 108, and performs the channel fluctuation compensation. The correlation value is output to 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 Early correlation value to the integrator 112.

The late correlator 107 obtains an L obtained by correlating the spread modulation signal with the spread code replica.
ate correlation value is output to channel fluctuation compensation section 302.

Channel fluctuation compensating section 302 performs channel fluctuation compensation of the late correlation value output from late correlator 107 using the channel fluctuation estimated value output from channel estimating section 108, and performs L
The ate correlation value is output to the integrator 112.

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

The integrator 112 controls the channel fluctuation compensation unit 30
The weight determination unit 202 adds the Early integration value obtained by integrating the Early correlation value output from 1 in a predetermined time unit to the Early integration value.
Are multiplied by the weight information output from the control unit and output to the obtained tracking determination unit 114.

The integrator 113 controls the channel fluctuation compensator 30
2 is multiplied by the weight information output from the weight determination unit 202 to the Late integrated value obtained by integrating the Late correlation value output from the second unit in a predetermined time unit, and is output to the obtained tracking determination unit 114.

Actually, a plurality of processing blocks are connected in parallel for each multipath so as to process a plurality of spread modulation signals having different reception timings by using a plurality of despreading units of the present invention. The outputs are 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 the signal obtained by despreading. By performing the synchronization tracking, even if the received signal is deteriorated due to the influence of fading or the like, the synchronization tracking can be performed more accurately, and the reception performance can be improved.

(Embodiment 4) A CDMA receiving apparatus according to Embodiment 4 of the present invention compensates for channel fluctuation in the result of despreading used for synchronization tracking and weights based on the reception quality of a signal obtained by despreading. And perform synchronization tracking.

FIG. 7 is a block diagram showing an example of the configuration of the despreading unit of the CDMA receiving apparatus according to Embodiment 4. However, components common to FIG. 1 or FIG. 3 are assigned the same reference numerals as in FIG. 1 or FIG.

The CDMA receiving apparatus of FIG. 7 differs from FIG. 3 in that it has a reception SIR measuring section 401 and a weight determining section 402 and obtains weight information from the SIR ratio of the received signal.

In FIG. 7, channel fluctuation compensating section 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 the synchronous detection result is output to the reception SIR measurement unit 401 and outside.

Receiving SIR measuring section 401 measures the SIR of the synchronous detection output for each predetermined signal section, and outputs the SIR to weight determining section 402.

The weight determining section 402 determines weight information based on the SIR and outputs the information to the integrators 112 and 113. For example, the weight determining unit 402 uses the received SIR as it is as weight information. Further, it is also possible to convert the received SIR into weight information using a conversion table and determine the weight information.
When the reception SIR is equal to or greater than a predetermined threshold, the weight information is set to 1,
Below the threshold value, it can be set to 0.

The integrator 112 is connected to the early correlator 106
Are multiplied by the early integration value obtained by integrating the Early correlation value output from the unit in a predetermined time unit and the weight information output from the weight determination unit 402, and output to the tracking determination unit 114 obtained.

The integrator 113 multiplies the Late integrated 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 determining unit 402, 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 based on the desired signal to noise wave ratio of a signal obtained by despreading. By performing weighted synchronization tracking, synchronization tracking can be performed more accurately even when a received signal is degraded due to fading or the like, and reception performance can be improved.

Although the CDMA receiving apparatus of the present invention applies a weight to the integral value in a predetermined time unit, the time unit is not particularly limited. For example, it is also possible to calculate a weight to be applied to the integral value for each slot and to apply a weight to the integral value.

[0133]

As described above, according to the present invention,
In the despreading process of the CDMA reception, more accurate synchronization tracking can be performed, and a received signal of better quality can be obtained.

[Brief description of the drawings]

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

FIG. 2 is a diagram showing an example of a conversion table used when creating weight information according to the embodiment.

FIG. 3 is a diagram showing an integrated value in tracking determination according to the embodiment.

FIG. 4 is a block diagram showing an example of a configuration of a despreading unit of a CDMA receiving apparatus according to Embodiment 2.

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

FIG. 6 is a block diagram showing an example of a configuration of a despreading unit of a CDMA receiving apparatus according to Embodiment 3.

FIG. 7 is a block diagram illustrating an example of a configuration of a despreading unit of a CDMA receiving apparatus according to Embodiment 4.

FIG. 8 is a block diagram showing a configuration of a despreading unit in a conventional CDMA receiver.

FIG. 9 is a diagram showing an integrated value in a conventional tracking determination.

FIG. 10 is a diagram showing an integrated value in a conventional tracking determination.

[Explanation of symbols]

 Reference Signs List 101 search unit 102 spreading code replica generation unit 103 delay unit 104 shift register 105 reference correlator 106 Early correlator 107 Late correlator 108 channel estimation unit 109, 301, 302 channel fluctuation compensation unit 110 reception level measurement unit 111, 202, 402 Weight determination unit 112, 113 Integrator 114 Tracking determination unit 201, 401 Received SIR measurement unit

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[Procedure amendment]

[Submission date] September 7, 2001 (2001.9.7)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction contents]

The tracking determination section 22 compares the Early integration value with the Late integration value. If the Early integration value is larger than the Late integration value, the tracking determination section 22 outputs an instruction to advance the reception timing to the delay section. La
If it is smaller than the te integration value, an instruction to delay the reception timing is output to the delay unit 13.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0066

[Correction method] Change

[Correction contents]

The tracking determination section 114 is provided with the integrator 11
2 is compared with the value of the Late integrated value output from the integrator 113, and the Early integrated value is compared with the Early integrated value.
When the integrated value is larger than the Late integral value, an instruction to advance the reception timing is output to the delay unit, and when the Early integrated value is smaller than the Late integral value, an instruction to delay the reception timing is output to the delay unit 103.

Claims (12)

[Claims] 1. A despreading means for despreading a spread signal at a predetermined reception timing to output a reference despread value, a weight determining means for 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 the reception timing, first calculating means for outputting a first correlation value obtained by multiplying the despread result by the weight, and applying the spread signal to the spread signal at a timing later than the reception timing. After performing despreading, a second computing unit that outputs a second correlation value obtained by multiplying the despread result by the weight, and the reception timing based on a comparison result between the first correlation value and the second correlation value. And a changing means for changing the value of the CDMA receiver. 2. The CDMA receiving apparatus according to claim 1, wherein the weight determining means determines a smaller weight 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 a value obtained by adding a predetermined number of despread results by a weight. The CDMA receiver according to claim 1 or 2, wherein 4. The CDMA receiving apparatus according to claim 1, wherein the weight determining means determines the weight based on a reception level of the reference despread value. 5. A channel fluctuation estimating means for estimating the amplitude or phase fluctuation of the reference despread value, and a compensating means for compensating for the amplitude or phase fluctuation of the reference despread value based on the estimation result of the channel fluctuation estimating means. The weight determining means determines the weight based on the reception level of the reference despread value that has compensated for the fluctuation of the amplitude or the phase. CD described in Crab
MA receiver. 6. The CDMA receiver 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. 7. A channel fluctuation estimating means for estimating a fluctuation in amplitude or phase of a reference despread value, and a compensating means for compensating for a fluctuation in amplitude or phase of a reference despread value based on an estimation result of the channel fluctuation estimating means. Wherein the weight determining means determines the weight based on a desired wave-to-interference wave ratio of the reference despread value that compensates for amplitude or phase fluctuations. Item 4. The CDMA receiving device according to any one of Items 3. 8. The CDM according to claim 7, wherein the weight determining means determines the weight based on a table that associates the desired wave-to-interference wave ratio of the reference despread value with the weight.
A receiving device. 9. A first channel compensator for performing amplitude or phase compensation on the first correlation operation result based on the estimation result of the channel fluctuation estimator, and a second correlation operation result based on the estimation result of the channel fluctuation estimator. And a second channel compensating means for compensating for the 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. And
9. The apparatus according to claim 5, wherein the second operation unit multiplies the second correlation operation result, for which the amplitude or phase is compensated by the second channel compensation unit, by a weight. 10. CDMA receiver. 10. A base station apparatus comprising the CDMA receiver according to any one of claims 1 to 9. 11. A communication terminal device comprising the CDMA receiving device according to claim 1. Description: 12. A despreading step of despreading a spread signal at a predetermined reception timing to output a reference despread value, a weight determining step of determining a weight based on reception quality of the reference despread value, After performing despreading on the spread signal at a timing earlier than the reception timing, a first operation step of outputting a first correlation value obtained by multiplying the despread result by the weight, and applying the spread signal at a timing later than the reception timing 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 timing based on a comparison result between the first correlation value and the second correlation value A CDMA receiving method, comprising: