JP2001156683A - Spread spectrum demodulator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spread spectrum demodulator in which an active correlation processing is applied as an inverse spread processing that can reduce the manufacturing time when a plurality of spread rates are variable. SOLUTION: A spread demodulation section of this spread spectrum demodulator is provided with a partial inverse spread processing section. The partial inverse spread processing section employs the active correlation processing to apply inverse spread processing to a spread spectrum signal based on a reference code of a fixed partial spread rate with a length equal to that of a shortest spread rate among a plurality of spread rates. The partial inverse spread processing section conducts the processing above to obtain a partial symbol signal consisting of partial symbols each having a length equal to or less than one symbol length. The partial symbol signal is detected by a pilot synchronizing signal and integrated by a symbol integration section. The number of integration times in this case is equivalent to the ratio of the spread rate to the partial spread rate. Accordingly, the original data symbol with one symbol length can be decoded. Thus, it is enough to conduct operation verification as to one kind of the partial spread rate in most parts of the partial inverse spread processing section.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus provided in a spread spectrum receiver applied to, for example, a mobile station and a base station of a mobile communication system to demodulate a received spread spectrum signal.

[0002]

2. Description of the Related Art At present, application of spread spectrum communication to mobile communication is being actively studied. Among them, CDMA (Code Division), which is a multiple access method using the direct spreading method,
Multiple Access) is a flexible service
It is considered that there is an advantage in terms of effective utilization of the frequency band. Therefore, CDMA has been standardized as one of the access methods of the third generation mobile communication system.

In direct spread spectrum communication,
A spread spectrum signal is created and transmitted using a spread code that is irrelevant to the information signal to be transmitted and has a wider bandwidth than the information signal. When demodulating this spread spectrum signal, use the same reference code as the spread code on the transmitting side,
The spread spectrum signal is despread using this reference code.

[0004] The despreading process of the spread spectrum signal is roughly classified into a so-called active correlation process and a passive correlation process. In the active correlation process, a received spread spectrum signal is multiplied by a reference code while being shifted in time, and the multiplication result is integrated over one period of the reference code to obtain a correlation value. On the other hand, in the passive correlation processing, a matched filter is used, and a correlation value is obtained by multiplying the matched filter by a tap coefficient corresponding to a predetermined spreading code and a spread spectrum signal. A passive correlator represented by a matched filter generally has a complicated structure and a large scale as compared with an active correlator. Therefore, when configuring a spread spectrum receiver at low cost,
Generally, an active correlator is used.

FIG. 14 is a block diagram showing a configuration of a conventional spread spectrum demodulator to which an active correlator is applied.
An analog baseband signal corresponding to the received spread spectrum signal is converted into a digital baseband signal by an A / D (Analog / Digital) conversion unit (not shown).
It is provided to a despreading unit 90. The despreading unit 90 restores a symbol signal including the original symbol from the spread spectrum signal by performing an active correlation process based on the reference code generated by the reference code generation unit 91.

The active correlation processing will be described in more detail.
The active correlation processing is repeatedly performed for each symbol which is one unit after the narrowband modulation. That is, if a certain unit time is one slot, the active correlation process sets one slot to one slot.
For each time obtained by dividing by the number of symbols included in the slot, the multiplication processing of the received signal and the reference code and the integration processing of the result are repeatedly executed. Thus, the original information is restored for each symbol.

[0007] The symbol signal restored by the despreading section 90 is provided to a pilot synchronous detection section 92. The pilot synchronous detector 92 synchronously detects the symbol signal based on pilot symbols included in the symbol signal. That is, pilot synchronization detection section 92 extracts pilot symbols included in the symbol signal in pilot symbol selection section 93, and performs channel estimation section 9
In step 4, a reference phase is obtained. Further, the pilot synchronization detector 92 delays the symbol signal by the processing delay unit 95, and then detects the symbol signal by the complex multiplier 96 based on the reference phase. Thus, the original information is restored.

Meanwhile, in the third generation mobile communication system, in order to provide users with information services and applications of various transmission rates, a plurality of spreading factors (Sp
The reading rate (SF) is selectively used as needed, so that the bit rate can be changed. This is, for example, the fact that 3GPP (3rd Generation Partnership Pr
oject) standardization document "TS25.211 Ver.3.0.0 (1997-0), p9
or p17 ".

More specifically, in the technique disclosed in this standard, a plurality of spreading factors are set as powers of two. The spreading factor indicates how many chips in one cycle of the spreading code have been used to spread one symbol, and corresponds to a value obtained by dividing the chip rate by the symbol rate. On the other hand, since the chip rate determines the transmission bandwidth, it is difficult to change it unnecessarily. Therefore, when the chip rate is kept constant and the spreading factor is changed, the symbol rate changes. As a result, the bit rate changes.

For example, when the spreading factor is set to a relatively small value, the number of symbols to be spread by one cycle of the spreading code becomes relatively large. Therefore, the symbol rate is relatively high, and consequently the bit rate is high. Conversely, when the spreading factor is set to a relatively large value, the number of symbols to be spread by one cycle of the spreading code becomes relatively small. Therefore, the symbol rate becomes slow, and as a result, the bit rate also becomes slow.

For this reason, for example, a reference code with a large spreading factor is usually assigned, and when a high-speed information service or the like is required, a reference code with a small spreading factor is assigned according to the demand. Can be. By doing so, it is possible to improve the service to the users while securing the number of users.

[0012]

As described above, it is desirable to use an active correlator as a despreader in order to manufacture a spread spectrum receiver at low cost. Therefore, in order to manufacture a spread spectrum demodulator at low cost and to improve the service to users, it is conceivable to apply the technology disclosed in the above-mentioned standard to a spread spectrum demodulator using an active correlator. . However, in this case, since the technique disclosed in the above-mentioned standard uses a plurality of spreading factors, there is a problem that the manufacturing period of the spread spectrum demodulation device is lengthened and the manufacturing process is complicated.

More specifically, as described above, changing the spreading factor changes the symbol rate. On the other hand, since the active correlation processing is performed every time obtained by dividing one slot by the number of symbols included in one slot, if the symbol rate changes, the execution period of the active correlation processing must also be changed. For example, when the spreading factor is 16, the multiplication process and the integration process are repeatedly executed in one slot at a time interval of 16 chips, while when the spreading factor is 256, the multiplication process is performed at a time interval of 256 chips. Must be repeatedly executed during one slot.

Therefore, the interval at which the despreading process is performed,
In other words, the output timing of the pulse and the control signal must depend on the spreading factor. Therefore, for example, if eight types of spreading factors are set, the despreading unit 9
0, pilot symbol selection unit 93, channel estimation unit 9
4. The design and operation verification of the operation timing of the processing delay unit 95 and the complex multiplication unit 96 must be performed for each of the eight spreading factors. Therefore, the manufacturing time is prolonged and the manufacturing process is complicated.

An object of the present invention is to solve the above-mentioned technical problem, to reduce the manufacturing time when the active correlation processing is applied as the despreading processing and when a plurality of spreading factors can be changed. It is an object of the present invention to provide a spread-spectrum demodulation apparatus capable of performing the above.

[0016]

In order to achieve the above object, the present invention provides a method for generating a pilot symbol and a data symbol based on a spreading code having one of a plurality of preset spreading factors. A spread-spectrum demodulator for demodulating a spread-spectrum signal including a spread-spectrum signal based on a reference code of a partial spread rate having a length equal to or shorter than a shortest spread rate among the plurality of spread rates. And a partial despreading unit for obtaining a partial symbol signal composed of partial symbols having a length of one symbol or less, and a partial symbol signal obtained by the partial despreading unit as pilot symbols. A pilot synchronous detection unit that performs synchronous detection based on the
And a symbolizing integrator for integrating the partial symbol signal after the synchronous detection by the pilot synchronous detector to restore a data symbol composed of the original symbol of one symbol length.

[0017]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

Embodiment 1 FIG. 1 is a conceptual diagram showing a configuration of a mobile communication system to which a spread spectrum demodulator according to Embodiment 1 of the present invention is applied. This mobile communication system uses a so-called third generation mobile communication system, and uses CDMA as a communication access system. More specifically, the mobile communication system has a base station 1 and a mobile station 2, and achieves mobile communication by wirelessly communicating a spread spectrum signal between the base station 1 and the mobile station 2.

For example, the base station 1 includes a spread spectrum transmitter 3. The spread spectrum transmitter 3 narrow-band modulates communication data to create a symbol signal. Specifically, spread spectrum transmitter 3 inserts pilot data into a communication data sequence and converts the data into, for example, QPSK.
(Quadrature Phase Shift Keying). As a result, a symbol signal composed of pilot symbols and data symbols is obtained. The unit length in this case is one symbol. Further, spread spectrum transmitter 3 creates a spread spectrum signal by multiplying the symbol signal by a spread code, and transmits this spread spectrum signal to mobile station 2.
Send to

The mobile station 2 has a spread spectrum receiver 4. The spread spectrum receiver 4 receives the spread spectrum signal transmitted from the spread spectrum transmitter 3, despreads this spread spectrum signal by active correlation processing to obtain a symbol signal, and performs the opposite of the narrow band modulation. A narrowband demodulation process, which is a process, is performed on the symbol signal to obtain original communication data.

The spread spectrum transmitter 3 will be described in more detail. When spreading a symbol signal, the spread spectrum transmitter 3 spreads the symbol signal based on a spread code having a plurality of spreading factors SF. Here, the spreading factor SF is 1
This indicates how many chips the symbol has been spread, and corresponds to a value obtained by dividing the chip rate by the symbol rate. Specifically, the spreading factor SF is expressed as a power of 2, that is, 2 ^M (for example, M = 2, 3,..., 8).
Numerical values such as 8, 16,... 256 are taken.

In the spread spectrum transmitter 3, the plurality of set spreading factors SF are selectively used according to a transmission rate suitable for providing an information service and an application. More specifically, when providing a relatively low-speed information service or the like, the spread spectrum transmitter 3 uses a spread signal with a relatively large spreading factor SF,
Spread symbol data. As a result, a spread spectrum signal having a relatively low symbol rate, that is, a relatively low bit rate can be obtained. On the other hand, when providing a relatively high-speed information service or the like, the spread spectrum transmitter 3 spreads symbol data using a spread signal with a relatively small spreading factor SF. As a result, a spread spectrum signal having a relatively high symbol rate, that is, a relatively high bit rate can be obtained.

FIG. 2 is a diagram for explaining a difference in symbol rate due to a difference in spreading factor SF. 2 (a) to 2 (e) show that the spreading factor SF is 256, 128, 6 respectively.
The numbers of symbols included in one slot when the numbers are set to 4, 32, and 16 are shown. For example, assuming that the number of symbols included in one slot is 10 when the spreading factor SF is 256 as shown in FIG.
Is changed to 128, which is half of that, the number of symbols is doubled to 20, as shown in FIG. Also, the diffusion rate S
When F is changed to 64, 32, and 16, the number of symbols becomes 40, 8 as shown in FIGS.
0 and 160. That is, as the spreading factor SF decreases, the symbol rate increases.

FIG. 3 is a block diagram showing the internal configuration of the spread spectrum receiver 4. As shown in FIG. Spread spectrum receiver 4
Includes a receiving unit 10. The receiving unit 10 includes the base station 1
, And sends the spread spectrum signal to the analog signal processing unit 11. Analog signal processing unit 11
Creates an analog baseband signal by converting a spread spectrum signal from a carrier band to a baseband band. The analog baseband signal is provided to the A / D converter 12. The A / D converter 12 converts the analog baseband signal into a digital baseband signal, and supplies the digital baseband signal to the spread spectrum demodulator 13.

The spread spectrum demodulator 13 restores the original data symbols by demodulating the digital baseband signal. More specifically, the spread spectrum demodulation unit 13 includes a partial despreading unit 14.
The partial despreading unit 14 partially despreads the digital baseband signal by active correlation processing. More specifically, partial despreading processing 14 partially despreads the digital baseband signal using the reference code generated by reference code generation section 15 at intervals corresponding to partial spreading factor PSF.
Here, the partial despreading is a partial spreading rate PS which is a fixed value.
This is a process for despreading the digital baseband signal using the reference code F. In the first embodiment, the partial diffusion rate P
The SF has a length equal to the shortest spreading factor SF among a plurality of spreading factors SF set in the spread spectrum transmitter 3 and is expressed as 2 ^P (P is a natural number smaller than M). As a result, a partial symbol signal including one or more partial symbols obtained by dividing one symbol at the time of transmission is obtained. That is, the partial symbol has a length of one symbol or less. The partial symbol signal is provided to pilot synchronous detection section 16.

The partial despreading unit 14 can be realized by hardware or software processing by a DSP or the like. In this case, it can be applied to a software mobile station corresponding to a plurality of spreading factors SF. effective.

The pilot synchronous detection section 16 solves the narrow band modulation of the partial symbol signal by performing synchronous detection based on the pilot symbol in the partial symbol signal. More specifically, the pilot synchronous detection unit 16
Pilot symbolizing integrator 17, channel estimator 1
8, a processing delay unit 19 and a complex multiplication unit 20. The partial symbol signal is provided to pilot symbolizing integration section 17 and processing delay section 19.

The pilot symbolizing and integrating section 17 restores the pilot symbols included in the partial symbol signal. More specifically, pilot symbolization integration section 17 extracts a portion corresponding to a pilot symbol from the partial symbol signal provided from partial despreading section 14. Thereafter, the pilot symbolizing integration section 17
Is obtained by integrating a portion corresponding to the extracted pilot symbol a predetermined number of times to obtain an original 1
Recover pilot symbols of symbol length. Pilot symbolization integration section 17 provides the restored original pilot symbols to channel estimation section 18.

The channel estimator 18 performs channel estimation based on the restored pilot symbol phase. Specifically, the channel estimator 18 extracts a reference phase based on the phase of the pilot symbol, and supplies the reference phase to the complex multiplier 20.

Processing delay section 19 delays the partial symbol signal supplied from partial despreading section 14 for a predetermined time. The predetermined time is set to a time equal to a time required for restoring pilot symbols and extracting a reference phase. The processing delay unit 19 supplies the delayed partial symbol signal to the complex multiplier 20.

The complex multiplier 20 synchronously detects the partial symbol signal based on the reference phase. More specifically, complex multiplier 20 narrow-band demodulates the partial symbol signal by removing the reference phase component from the partial symbol signal. As a result, a modulated partial symbol signal can be obtained. The demodulated partial symbol signal is output as an output of the pilot synchronous detection unit 16 by the symbolization integration unit 21.
Given to.

The symbolizing integrator 21 restores the original one-symbol data symbol from the demodulated partial symbol signal. As described above, the partial symbol signal is a signal composed of partial symbols having a length of one symbol or less. Therefore, the symbolizing integration section 21 repeatedly integrates the partial symbol signal until it becomes one symbol,
The original data symbol of one symbol length is restored.

FIG. 4 is a conceptual diagram for explaining the processing from the creation of the partial symbol signal to the restoration of the original data symbol in more detail. As described above, the partial symbol signal is created by using the reference code of the partial spreading factor PSF having a length equal to the shortest spreading factor SF among the plurality of spreading factors SF set on the transmitting side. That is, the partial despreading unit 14 multiplies the digital baseband signal by the reference code, integrates the result of the multiplication over a time corresponding to 2 ^P chips, which is the partial spreading factor PSF, and discharges.

As a result, it is possible to obtain a partial symbol obtained by despreading one symbol spread with a spreading code of a spreading factor SF of 2 ^M chips with a reference code of a partial spreading factor PSF of a 2 ^P chip. In other words, assuming that the ratio between the spreading factor SF and the despreading factor PSF used on the transmission side is R, the partial symbol length included in the partial symbol signal is 1 / R of one symbol.

As described above, the partial symbol signal composed of 1 / R partial symbols of one symbol is supplied to the pilot symbol conversion and integration section 17 of the pilot synchronous detection section 16. Pilot symbolization integration section 17 extracts a pilot symbol from the partial symbol signal. In this case, it is necessary to return the partial symbols to one symbol length. Therefore,
Pilot symbolization integration section 17 integrates a portion corresponding to a pilot symbol included in the partial symbol signal R times. By doing so, a pilot symbol of one symbol length can be restored.

Further, a partial symbol signal composed of 1 / R partial symbols of one symbol length is supplied to the symbolizing integrator 21 after undergoing synchronous detection. Even in this case, it is necessary to return the partial symbols to one symbol.
The symbolizing integrator 21 integrates the partial symbol signal R times. By doing so, a data symbol of one symbol length can be restored.

As described above, according to the first embodiment, the partial despreading unit 14 only needs to be able to perform despreading with the partial spreading factor PSF corresponding to the shortest spreading factor SF among a plurality of spreading factors SF. The operation timing design and operation verification need only be based on one kind of partial spreading factor PSF. Also,
The channel estimator 18, the processing delay unit 19, and the complex multiplier 20 only need to design operation timing for the partial spreading factor PSF. Only the pilot symbolizing and integrating unit 17 and the symbolizing and integrating unit 21 need to design the operation timing for all of the plurality of spreading factors SF.

Therefore, the operation timing design and the like can be greatly reduced in comparison with the prior art in which the operation timing design and the like have to be performed in all the parts in all of the plurality of spreading factors SF. More specifically, the work for designing the operation timing and the like can be reduced to about half. Therefore, the manufacturing time of the spread spectrum demodulation unit 13 can be significantly reduced, and the manufacturing process can be greatly simplified. Therefore, the spread spectrum demodulation unit 1
3 can reduce the manufacturing cost.

Also, in the case where a plurality of spread spectrum demodulation units 13 are manufactured, and in the case where a spread spectrum signal created based on a spreading code of a spreading factor SF as a fixed value different from each other is demodulated, The plurality of spreading factors S
Partial diffusivity P having a length equal to the shortest diffusivity SF of F
By manufacturing the spread spectrum demodulation unit 13 that performs despreading with SF, the manufacturing time of the plurality of spread spectrum demodulation units 13 can be reduced.

More specifically, consider the case of manufacturing two types of demodulators, for example, a demodulator for high-speed data communication and a demodulator for voice only. It is assumed that the voice-only demodulator demodulates a spread spectrum signal created based on a relatively large spreading factor SF, for example, a spreading code of 128. The high-speed data communication demodulator shall demodulate a spread spectrum signal created based on a relatively small spreading factor SF, for example, 32 spreading codes. In this case, two types of spreading factors SF of 128 and 32 are set in advance. Also, the spreading factor SF in this case
Is expressed as a power of 2 and has a relatively small spreading factor SF.
Is a length of a power of 2 of the relatively large spreading factor SF.

In the above case, the spread spectrum demodulation unit 13 that performs the despreading process using the shortest 32 reference codes of the two types of spreading factors SF as the partial spreading factor PSF is manufactured. More specifically, as the spread spectrum demodulation unit 13 applied to the demodulation device for high-speed data communication, there is provided a partial despreading unit 14 for performing despreading processing with a reference code of 32 as a partial spreading factor PSF. = 32
A device having a pilot symbolizing integrator 17 and a symbolizing integrator 21 that performs an integration process at the time of / 32 = 1 is manufactured. Also, as the spread spectrum demodulation unit 13 applied to the audio-only demodulation device, a partial despreading unit 14 that performs despreading processing with a reference code of 32 as a partial spreading factor PSF is provided, and R = 128/32 = 4 A device having a pilot symbolizing integrator 17 and a symbolizing integrator 21 that performs the integration process by the number of times is manufactured.

By doing so, the design and operation verification of the operation timing of the parts other than the pilot symbolization integration unit 17 and the symbolization integration unit 21 are performed as 1
It only needs to be performed based on the type of partial spreading factor PSF. That is, the operation timing design and the like of the high-speed data communication demodulator and the voice-only demodulator can be shared to some extent. Therefore, it is possible to greatly reduce the work required for designing operation timing and the like. Therefore, the time required to manufacture the plurality of demodulation devices can be shortened as a whole, and the manufacturing process can be greatly simplified.

In the above description, the length of the partial spreading factor PSF is set to be equal to the shortest spreading factor SF among the plurality of spreading factors SF. However, for example, the length of the partial spreading factor PSF may be set to be shorter than the shortest spreading factor SF among the plurality of spreading factors SF. More specifically, the length of the partial spreading factor PSF is set to, for example, a half of the shortest spreading factor SF, such as half of the shortest spreading factor SF. By doing so, as in the case of the above description, the time and effort required for designing the operation timing and the like can be reduced.

Embodiment 2 FIG. 5 is a block diagram showing a configuration of a spread spectrum demodulation unit 13 according to Embodiment 2 of the present invention. 5, the same reference numerals are used for the same functional parts as those in FIG.

In the first embodiment, the case where pilot data is time-multiplexed and inserted into a data sequence is described as an example. On the other hand, the second embodiment exemplifies a case where pilot data is transmitted using a channel different from the data sequence.

More specifically, in the second embodiment, spread spectrum transmitter 3 spreads pilot symbols with a first spreading code, and also spreads data symbols with a second spreading code different from the first spreading code. A spread spectrum signal is created by spreading and code-multiplexing the pilot symbol with a data symbol. As described above, in the second embodiment, the pilot symbol is spread with a spreading code different from the data symbol, so that the pilot symbol and the data symbol need to be separately despread on the receiving side.

For this reason, the spread spectrum receiver 4 according to the second embodiment includes a pilot channel despreading unit 25 provided independently of the pilot synchronous detection unit 16 as a configuration for extracting pilot symbols. The digital baseband signal is supplied to the pilot channel despreading unit 25 in parallel with the partial despreading unit 14.

The reference code generator 15 provided in the spread spectrum receiver 4 has a first reference code that is the same as the first spread code and a second reference code that is the same as the second spread code. Generate a sign. Reference code generator 1
5 designates a first reference code as a pilot channel despreader 25.
, And a second reference code to the partial despreading unit 14.

[0049] Pilot channel despreading section 25 restores pilot symbols by multiplying the digital baseband signal by a first spreading code. In this case, the digital baseband signal includes a one-symbol pilot symbol. Therefore, unlike Embodiment 1, it is possible to restore a pilot symbol of one symbol length by simply performing despreading without performing R-times integration. The pilot channel despreading unit 25 outputs the restored pilot symbols to the pilot synchronous detection unit 16.
Is directly input to the channel estimating unit 18.

As described above, according to the second embodiment, even when a pilot symbol is inserted into a spread spectrum signal by code multiplexing, almost all of the spread spectrum demodulation sections 13 have one type, as in the first embodiment. Since it is only necessary to design and verify the operation timing of the partial spreading factor PSF, it is possible to greatly reduce the work required for designing the operation timing and the like.

Third Embodiment FIG. 6 is a block diagram showing a configuration of a spread spectrum demodulation unit 13 according to a third embodiment of the present invention. 6, the same reference numerals are used for the same functional parts as in FIG.

The spread spectrum demodulation unit 13 according to the third embodiment is obtained by applying the configuration of the spread spectrum demodulation unit according to the first embodiment to RAKE reception. More specifically, the spread spectrum demodulation unit 13 includes a plurality of finger units 30. Each finger unit 30 separately despreads a spread spectrum signal that has propagated through a different propagation path based on the reference code given from the reference code generation unit 15.

More specifically, the finger unit 30 includes a partial despreading unit 14 and a pilot synchronous detection unit 16, respectively.
And a symbolizing integration unit 21, and further, a first delay unit 31 and a second delay unit 32. The first delay unit 31 delays the reference code over a time corresponding to the propagation delay time, and inputs the reference code to the partial despreading unit 14. The second delay unit 32 includes the symbolizing integrator 2
1 delays the data symbol output from 1 for the same time as the first delay unit 31.

In this configuration, the reference code generated by the reference code generation section 15 is given to the partial despreading section 14 after being delayed by the first delay section 31 of each finger section 30. Thereby, the partial despreading unit 14 despreads the digital baseband signal at a timing according to the propagation delay time.

The partial symbol signal obtained after despreading is
After being synchronously detected by the pilot synchronous detector 16, the symbol is integrated by the symbolizing integrator 21 to become an original data symbol. This data symbol is delayed in the second delay unit 32. This delay time is the same as the delay time in the first delay unit 31. Therefore, the data symbols output from the respective finger units 30 have the same timing. Each finger unit 30 gives a data symbol to the RAKE combining unit 33, respectively.

The RAKE synthesizing unit 33 includes the respective finger units 30
Is RAKE-combined. As a result, it is possible to obtain a data symbol from which the influence of multipath fading has been removed.

As described above, according to the third embodiment, R
Also in the spread spectrum demodulation unit 13 that performs AKE reception, most of the spread spectrum demodulation unit 13 need only design and verify the operation timing for one type of partial spreading factor PSF as in the first embodiment. Time and effort for designing the timing can be greatly reduced.

The configuration of the third embodiment may be combined with the configuration of the second embodiment. FIG. 7 is a block diagram illustrating a configuration of the spread spectrum demodulation unit 13 when the configuration of the second embodiment is combined with the configuration of the third embodiment. The spread spectrum demodulation unit 13 includes a pilot channel despreading unit 25 provided independently of the pilot synchronous detection unit 16 as a configuration for extracting pilot symbols. In this connection, each finger 3
0 is provided with a third delay unit 35 for giving a delayed reference code to the pilot channel despreading unit 25. The delay time of the third delay unit 35 is the same as the delay time of the first delay unit 31 of each finger unit 30.

According to this configuration, even when pilot symbols are code-multiplexed and transmitted and RAKE reception is performed, the spread spectrum demodulation section 1
In most of the cases, only the operation timing design and operation verification for one kind of partial spreading factor PSF need be performed, so that it is possible to greatly reduce the trouble of designing the operation timing and the like.

Fourth Embodiment FIG. 8 is a block diagram showing a configuration of a spread spectrum demodulation unit 13 according to a fourth embodiment of the present invention. 8, the same reference numerals are used for the same functional parts as in FIG.

In the third embodiment, the operation timing of each finger unit 30 is set independently. On the other hand, in the fourth embodiment, the operation timing of each finger unit 30 is shared.

More specifically, the spread spectrum demodulation unit 13 includes a delay unit 40 with a tap. The tap delay section 40 delays the digital baseband signal output from the A / D conversion section 12 for a time corresponding to the propagation delay time, and extracts the digital baseband signal from a predetermined tap position. It is given to each finger unit 30 at a timing. Thus, the processing can be executed at a common timing in each finger unit 30.

As described above, according to the fourth embodiment, the operation timing of the finger unit 30 is shared. When the operation timings of the finger units 30 are made independent as in the third embodiment, it is necessary to design the operation timing and verify the operation of each finger unit 30 using different test patterns. However, when the operation timing of the finger units 30 is made common as in the fourth embodiment, it is only necessary to design the operation timing of each finger unit 30 using a common test pattern or to perform operation verification.
Therefore, it is possible to reduce the labor required for designing the operation timing and the like. Therefore, the manufacturing time can be shortened and the manufacturing process can be simplified.

The structure of the fourth embodiment may be combined with the structure of the second embodiment. FIG. 9 is a block diagram illustrating a configuration of the spread spectrum demodulation unit 13 in a case where the configuration of the second embodiment is combined with the configuration of the fourth embodiment. The spread spectrum demodulation unit 13 includes a delay unit 40 with a tap and a pilot channel despreading unit 25 provided independently of the pilot synchronous detection unit 16 as a configuration for extracting pilot symbols. In this connection, the digital baseband signal output from the tapped delay section 40 is
, The pilot channel despreading unit 25 and the partial despreading unit 1
4 and so on. On the other hand, the reference code generation unit 15 gives the first reference code to the pilot channel despreading unit 25 of each finger unit 30 and the second reference code to the partial despreading unit 14 of each finger unit 30.
Give a reference sign.

According to this configuration, a spread spectrum signal in which pilot symbols are inserted by code multiplexing is represented by R
Even in the case of AKE reception, since the operation timing of each finger unit 30 can be made common, the labor required for operation timing design and operation verification is further increased as compared with the case where the operation timing of each finger unit 30 is made independent. Can be reduced.

Embodiment 5 FIG. 10 is a block diagram showing a configuration of a spread spectrum demodulation unit 13 according to Embodiment 5 of the present invention. 10, the same reference numerals are used for the same functional parts as in FIG.

In the third embodiment, the pilot synchronous detector 16 is provided for each finger 30. On the other hand, in the fifth embodiment, the pilot synchronous detection unit 16
Are common to each finger unit 30, and the pilot synchronous detection unit 16 is used for each finger unit 30 in a time-division manner.

More specifically, the spread spectrum demodulation unit 13 includes a plurality of finger units 30, one data selector unit 45, and one pilot synchronous detection unit 16. The finger unit 30 includes a first delay unit 31, a partial despreading unit 14, and a second delay unit 32. The first delay unit 31 delays the reference code by a time corresponding to the propagation delay time, as in the third embodiment. Also, the second delay unit 32
Delays the partial symbol signal output from the partial despreading unit 14 by the same time as the delay time in the first delay unit 31. In this case, the number of stages of the second delay unit 32 is R times that of the first delay unit 31. This is because one symbol is divided into R in the partial despreading unit 14. With the above configuration, each finger unit 30 outputs a partial symbol signal whose timing is adjusted.

The partial symbol signal output from each finger unit 30 is applied to data selector unit 45. The data selector 45 time-division multiplexes each of the partial symbol signals and supplies the resultant to the pilot synchronous detector 16. The pilot synchronous detection unit 16 performs the synchronous detection process on the partial symbol signals corresponding to the respective finger units 30 in a time division manner, and sequentially provides the demodulated partial symbol signals to the symbolizing and integrating unit 21.

The symbolizing integrator 21 performs a process of integrating the partial symbol signal R times in a time-division manner. In this way, data symbols corresponding to each finger unit 30 can be obtained. Each data symbol is provided to RAKE combining section 46 and RAKE combined. Thus, the original data symbols are restored.

As described above, according to the fifth embodiment, only one pilot synchronous detector 16 is required, so that the circuit scale can be reduced. Therefore, the operation verification of pilot synchronous detection section 16 only needs to be performed once. Therefore, it is possible to further reduce the time and effort required for designing the operation timing and the like as compared with the case where the operation timing of each pilot synchronous detector 16 must be designed and verified for each of the plurality of finger units 30. Therefore, the manufacturing time can be further greatly reduced, and the manufacturing process can be further greatly simplified.

The configuration of the fifth embodiment may be combined with the configuration of the second embodiment. FIG. 11 is a block diagram illustrating a configuration of the spread spectrum demodulation unit 13 when the configuration of the second embodiment is combined with the configuration of the fifth embodiment. The spread spectrum demodulation unit 13 includes one pilot synchronous detection unit 16 and each finger unit 3
A pilot channel despreading unit 25 is provided in 0.
In addition, each finger unit 30 includes a third delay unit 35 that delays the first reference code to be given to the pilot channel despreading unit 25. Further, each finger unit 30 includes a fourth delay unit 50 that delays a pilot symbol output from pilot channel despreading unit 25.
By this means, pilot channel despreading section 25 can reliably restore the pilot symbols regardless of the propagation delay time, and can output the restored pilot symbols from finger section 30 at the same timing.

Further, the spread spectrum demodulation unit 1
3 includes a pilot selector unit 51. The pilot selector unit 51 provides the pilot symbol output from each finger unit 30 to the channel estimator 18 in the pilot synchronous detector 16. More specifically, pilot selector section 51 time-division multiplexes pilot symbols and uses them for channel estimation section 18 in order to use pilot synchronous detection section 16 in time division.

According to this configuration, a spread spectrum signal in which pilot symbols are inserted by code multiplexing is represented by R
Even in the case of AKE reception, the pilot synchronous detection unit 16 is shared by the plurality of finger units 30.
Therefore, similarly to the above description, the operation timing design and operation verification of the pilot synchronous detection unit 16 need only be performed for one despreading operation, so that the work required for the operation timing design and the like can be further reduced. .

Embodiment 6 FIG. 12 is a block diagram showing a configuration of a spread spectrum demodulator 13 according to Embodiment 6 of the present invention. 12, the same reference numerals are used for the same functional portions as those in FIGS. 8 and 10.

In the fifth embodiment, each finger unit 30 operates at an independent timing. On the other hand, in the sixth embodiment, the operation timing of each finger unit 30 is shared. That is, the sixth embodiment
The spread spectrum demodulation unit 13 according to the fourth embodiment has a configuration in which the common configuration of the pilot synchronous detection unit 16 in the fifth embodiment and the common operation timing of the finger unit 30 in the fourth embodiment are combined.

More specifically, the spread spectrum demodulation unit 13 includes a tap delay unit 40 that supplies a digital baseband signal to each finger unit 30 at the same timing as in the fourth embodiment. The output of the finger section 30 is supplied to a data selector section 45, and the partial symbol signal is supplied from the data selector section 45 to one pilot synchronous detection section 16 in a time division manner. The pilot synchronous detection unit 16 performs synchronous detection processing of the partial symbol signal for each finger unit 30, and outputs the result to the symbolizing integration unit 21. The symbolizing integration unit 21 integrates the partial symbol signal corresponding to each finger unit 30 and restores a data symbol corresponding to each finger unit 30. Thereafter, the RAKE combining unit 46 RAKE combines the data symbols of each finger unit 30. Thus, a final data symbol can be obtained.

As described above, according to the sixth embodiment, the pilot synchronous detector 16 is shared by the plurality of fingers 30 and the operation timing of the fingers 30 is shared. 5 and 5, the effort required for designing the operation timing and verifying the operation can be further reduced.

The configuration of the sixth embodiment may be combined with the configuration of the second embodiment. FIG. 13 is a block diagram illustrating a configuration of the spread spectrum demodulation unit 13 in a case where the configuration of the second embodiment is combined with the configuration of the sixth embodiment. The spread spectrum demodulation unit 13 shares the pilot synchronous detection unit 16 with a plurality of finger units 30, includes a tapped delay unit 40, and further has a configuration for extracting pilot symbols. A pilot channel despreading unit 25 is provided independently in the unit 30.

According to this configuration, even when a pilot symbol is inserted into a spread spectrum signal by code multiplexing, the operation timing of each finger unit 30 can be made common, and the pilot synchronization detection unit 16 can Since the finger unit 30 can be shared, operation time design and operation verification can be reduced.

Other Embodiments Embodiments of the present invention have been described above.
The present invention is not limited to the above embodiment.
For example, in the above embodiment, the case where the spread spectrum receiver 4 is provided in the mobile station 2 is taken as an example. However, the spread spectrum receiver 4 may be provided in the base station 1 as a matter of course.

[0082]

As described above, according to the present invention, in a spread spectrum demodulator in which a plurality of spreading factors are set in advance and an active correlation process is performed, a shortest spreading factor of the plurality of spreading factors is used. A partial symbol signal is created by performing an active correlation process based on a reference code of a partial spreading factor having a length equal to or less than the length, and after performing pilot synchronous detection, the partial symbol signal is integrated to obtain the original data. The symbol has been restored.

Therefore, only the extraction of pilot symbols and the integration of partial symbol signals at the time of pilot synchronous detection depend on the spreading factor used. Therefore, it is possible to reduce the time and effort required for designing the operation timing and the like as compared with the case where the operation timing is designed or the operation is verified in accordance with a plurality of spreading factors in all the portions. Therefore, the manufacturing time of the spread spectrum demodulator can be reduced, and the manufacturing process can be simplified.

Further, when the above-mentioned partial despreading section, pilot synchronous detection section and symbolizing integration section are provided in each of a plurality of finger sections, that is, when RAKE reception is performed,
The time required for operation verification decreases in inverse proportion to the number of finger portions. Therefore, the work required for operation timing design and operation verification can be further reduced, and the manufacturing time can be further simplified.

Furthermore, when a spread spectrum signal is input to the fingers at a timing corresponding to the propagation delay time, it is not necessary to operate each finger at an independent timing, so that the operation timing of each finger is designed. And operation verification can be performed using the same operation timing chart. Therefore, it is possible to further reduce the labor required for designing the operation timing and the like.

Furthermore, even when a pilot symbol is spread with a spreading code different from a data symbol, only the extraction of the pilot symbol and the integration of the partial symbol signal at the time of pilot synchronous detection depend on the used spreading factor. Therefore, it is possible to reduce the labor required for designing the operation timing and verifying the operation.

Further, when the pilot synchronous detector is used in common for a plurality of fingers, the operation as the pilot synchronous detector does not need to be verified for each finger. The work required for the design and operation verification of the device can be further reduced. Therefore, it is possible to further shorten the manufacturing time and simplify the manufacturing process.

Further, in this case, when a spread spectrum signal is input to the fingers at a timing corresponding to the propagation delay time, the design and verification of the operation timing of each finger may be performed using the same operation timing chart. Since it is possible, it is possible to further reduce the labor required for designing operation timing and the like.

Further, even when the pilot symbol is spread with a spreading code different from the data symbol,
As described above, it is possible to reduce the labor required for designing the operation timing and verifying the operation.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a configuration of a mobile communication system to which a spread spectrum demodulator according to Embodiment 1 of the present invention is applied.

FIG. 2 is a diagram for explaining a difference in the number of symbols due to a difference in spreading factor.

FIG. 3 is a block diagram illustrating a configuration of a spread spectrum receiver according to Embodiment 1.

FIG. 4 is a diagram illustrating partial symbolization and symbol restoration.

FIG. 5 is a block diagram showing a configuration of a spread spectrum demodulation unit according to Embodiment 2 of the present invention.

FIG. 6 is a block diagram illustrating a configuration of a spread spectrum demodulation unit according to Embodiment 3 of the present invention.

FIG. 7 is a block diagram showing a configuration in a case where a spread spectrum signal in which data symbols and pilot symbols are code-multiplexed in a spread spectrum demodulation unit according to Embodiment 3 is demodulated.

FIG. 8 is a block diagram illustrating a configuration of a spread spectrum demodulation unit according to Embodiment 4 of the present invention.

FIG. 9 is a block diagram showing a configuration in a case where a spread spectrum signal in which data symbols and pilot symbols are code-multiplexed in a spread spectrum demodulation unit according to Embodiment 4 is demodulated.

FIG. 10 is a block diagram illustrating a configuration of a spread spectrum demodulation unit according to Embodiment 5 of the present invention.

FIG. 11 is a block diagram showing a configuration when demodulating a spread spectrum signal in which a data symbol and a pilot symbol are code-multiplexed in the spread spectrum demodulation unit according to the fifth embodiment.

FIG. 12 is a block diagram illustrating a configuration of a spread spectrum demodulation unit according to Embodiment 6 of the present invention.

FIG. 13 is a block diagram illustrating a configuration in a case where a spread spectrum demodulation unit according to Embodiment 6 demodulates a spread spectrum signal in which data symbols and pilot symbols are code-multiplexed.

FIG. 14 is a block diagram illustrating a configuration of a conventional spread spectrum demodulator.

[Explanation of symbols]

13 Spread spectrum demodulator, 14 Partial despreader, 1
6 pilot synchronous detection section, 17 pilot symbolization integration section, 21 symbolization integration section, 25 pilot channel despreading section, 30 finger section, 33 RAKE
A combining unit, a delay unit with 40 taps, a 45 data selector unit, a 46 RAKE combining unit, and a 51 pilot selector unit.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5K022 EE02 EE13 EE33 5K047 AA15 BB01 GG34 HH15 MM33 MM35 MM36 5K059 DD35 EE02 5K067 AA02 CC10 CC24 EE02 EE10

Claims (7)

[Claims] 1. A spread spectrum demodulation apparatus for demodulating a spread spectrum signal generated based on a spreading code of any one of a plurality of preset spreading rates and including pilot symbols and data symbols, Based on a reference code of a partial spreading factor having a length equal to or less than the length of the shortest spreading factor among the plurality of spreading factors, by performing active correlation processing on the spread spectrum signal,
A partial despreading unit for obtaining a partial symbol signal composed of partial symbols having a length of one symbol or less; a pilot synchronous detection unit for synchronously detecting the partial symbol signal obtained by the partial despreading unit based on the pilot symbol; A spread symbol demodulation device for integrating a partial symbol signal after synchronous detection by the pilot synchronous detection unit to thereby restore a data symbol consisting of an original symbol of one symbol length. 2. The data conversion method according to claim 1, wherein the symbolization integration section integrates the partial symbol signal after the synchronous detection over a number of times corresponding to a ratio between a spreading factor of the spreading signal and a partial spreading factor. A spread spectrum demodulator for restoring symbols. 3. The device according to claim 1, wherein the partial despreading unit, the pilot synchronous detection unit, and the symbolizing integration unit are provided in a plurality of finger units, respectively, and output from each finger unit. RAKE data symbol
A spread spectrum demodulator, further comprising a RAKE combining unit for combining. 4. The method according to claim 1, wherein
A pilot symbol despreading unit that extracts a pilot symbol spread by a spreading code different from a data symbol from the spread spectrum signal, wherein the pilot synchronous detection unit is based on the pilot symbol extracted by the pilot symbol despreading unit. A spread symbol demodulator for synchronously detecting a partial symbol signal. 5. The method according to claim 1, wherein
The partial despreading unit is provided for each of a plurality of finger units, and further includes a data selector unit for time-division multiplexing and outputting the partial symbol signals output from each finger unit, and the pilot synchronous detection. The section is common to each of the finger sections, and is for time-divisionally synchronously detecting a partial symbol signal corresponding to each of the finger sections output from the data selector section. Restores data symbols by time-divisionally integrating partial symbol signals corresponding to the respective fingers after the synchronous detection by the pilot synchronous detector. The symbolized integrator restores the data symbols. A RAKE combining unit for RAKE combining data symbols corresponding to the respective finger units. Spectrum spread demodulator. 6. The spread spectrum demodulation device according to claim 3, further comprising a delay unit that outputs the spread spectrum signal to each of the finger units at a timing according to the propagation delay time. 7. Each of the finger units according to claim 5 or 6, further comprising a pilot symbol despreading unit for extracting a pilot symbol spread with a spreading code different from a data symbol from the spread spectrum signal. A pilot selector for outputting a pilot symbol extracted by the pilot symbol despreading unit of the finger unit in a time-division manner, wherein the pilot synchronous detection unit is configured to output each of the finger units in a time-division manner from the pilot selector unit. A spread-spectrum demodulator characterized in that a partial symbol signal corresponding to each finger is synchronously detected based on a pilot symbol corresponding to (1).