WO2003077438A1

WO2003077438A1 - Receiver and automatic frequency control method

Info

Publication number: WO2003077438A1
Application number: PCT/JP2002/002227
Authority: WO
Inventors: Hideyuki Takahashi; Katsuhiko Hiramatsu
Original assignee: Matsushita Electric Industrial Co., Ltd.
Priority date: 2002-03-11
Filing date: 2002-03-11
Publication date: 2003-09-18
Also published as: CN100502249C; AU2002236278A1; CN1516929A

Abstract

A searcher (105) creates a delay profile of a known symbol portion of a received base band signal by using a basic code, and a number-of-codes/kind-of-code determining unit (106) determines the number and kind of shift codes being used, on the basis of the delay profile. Correlators (108-1 to 108-n) compute the correlation values between the known symbol first half of the received base band signal and the shift code. Correlators (109-1 to 109-n) compute the correlation values between the known symbol second half of the received base band signal and the shift codes. A phase estimation unit (119) estimates the phase rotation per unit time by using the sum of the output signals of the correlators (108-1 to 108-n) and the sum of the output signals of the correlators (109-1 to 109-n). As a result, the influence of the cross-correlation of spreading codes and the influence of noises are suppressed, so that the phase rotation between the known symbols can be estimated highly precisely to realize highly precise AFC.

Description

Description Receiving device and automatic frequency control method

The present invention relates to a receiving device and an automatic frequency control method used in a CDMA wireless communication system. Background art

In recent years, wireless communication systems such as mobile phones and car phones have rapidly become widespread. In the communication terminal device of this wireless communication system, the receiving device performs automatic frequency control (hereinafter, referred to as “AFC”) in order to compensate for a difference in carrier frequency with the transmitting device.

Hereinafter, a conventional receiving apparatus will be described with reference to FIGS. FIG. 1 is a diagram showing a slot configuration of data transmitted from a transmission device. FIG. 2 is a block diagram showing a configuration of a conventional receiving apparatus.

As shown in FIG. 1, a transmitting device (not shown) transmits a signal including a known symbol 11 and a known symbol 12 spread by Code A and Code B, respectively. Here, the code lengths of C 0 de A and C 0 deB are tCA and tCB, respectively, and the interval between known symbols 11 and 12 is t gap.

The signal transmitted from the transmitting device is received via the antenna 21 by the receiving device shown in FIG. In FIG. 2, a signal (received signal) received by an antenna 21 is frequency-converted from a carrier frequency to a baseband by a reception RF unit 22. At this time, the reception RF unit 22 uses a local signal oscillated from an oscillator 38 described later. The in-phase component (I-ch) and quadrature component (Q-ch) of the baseband signal (reception paceband signal) output from the reception RF unit 22 are The signals are converted into digital signals by an A / D converter 23 and an A / D converter 24, respectively, and output to a searcher 25, a correlator 26, a correlator 27, and a correlator 28.

In the searcher 25, the received base-span signal converted to the digitized signal is correlated with CodeA, which is a known code, and the power of the correlation value exceeds the threshold value. Timing) t A is detected. Further, in the searcher 25, the reception timing tB of CodeB is calculated by tA + tgap. Further, in the search unit 25, the reception timing t Data at the beginning of the data part is calculated by tA + tCAZ2.

The searcher 25 outputs the reception timing at the beginning of the data section to the correlator 26 and the synchronous detector 29, the searcher 25 outputs the reception timing of Code A to the correlator 27, and the searcher 25 outputs the correlator. For Code 28, the reception timing of Code B is output.

In the correlator 26, based on the reception timing at the beginning of the data portion from the searcher 25, the correlation between the data portion of the received baseband signal and a predetermined spreading code (the spreading code assigned to the receiving device) is determined. Be taken. The data part of the received baseband signal after the correlation processing is output to the synchronous detector 29.

In the correlator 27, the known symbol 11 of the received baseband signal is correlated with CodeA based on the reception timing of CdeeA from the searcher 25. Similarly, the correlator 28 correlates the known symbol 12 of the received base span signal with CodeB based on the reception timing of the CodeB from the searcher 25.

In the synchronous detection unit 29, the synchronous detection process is performed on the data portion of the correlation-processed received paceband signal based on the first reception timing of the data portion from the searcher 25. The data part of the received baseband signal after the synchronous detection is demodulated by the demodulation unit 30, and the received data is extracted.

The in-phase component of the known symbol 11 of the correlated received baseband signal is delayed. The signal is delayed by t AB t CA / 2 + t gap + t CB / 2 (see Fig. 1) by the extension unit 31 and output to the complex correlation operation unit 33. Similarly, the quadrature component of the known symbol 11 of the received baseband signal subjected to the correlation processing is delayed by t AB (= t CA / 2 + t gap + t CB / 2) by the delay unit 3 Output to arithmetic section 33. The in-phase component and the quadrature component of the known symbol 12 of the received baseband signal subjected to the correlation processing are output to the complex correlation calculator 33, respectively.

The complex correlation operation unit 33 performs a complex correlation process using the in-phase components of the known symbol 11 and the known symbol 12 of the received received baseband signal _c . A complex correlation process is performed using the orthogonal components of the known symbol 11 and the known symbol 12 of the correlation-processed received baseband signal. The in-phase component and the quadrature component of the received base span signal after the complex correlation processing are output to phase estimating section 34.

The phase estimator 34 estimates the amount of phase rotation per unit time using the in-phase component and the quadrature component of the received baseband signal after the complex correlation processing output from the complex correlation calculator 33. The smoothing unit 35 calculates a frequency offset using the phase rotation amount estimated by the phase estimating unit 34. The calculated frequency offset is output to control voltage converter 36.

The control voltage converter 36 outputs a signal having a predetermined control voltage applied to the oscillator 38 in order to compensate for the calculated frequency offset. The signal output from the control voltage converter 36 is converted to an analog signal by the DZA converter 37 and then output to the oscillator 38. Thereby, the frequency of the local signal in oscillator 38 is controlled so as to compensate for the frequency offset.

As described above, the conventional receiving apparatus estimates the amount of phase rotation between known symbols in a received signal, calculates a frequency offset, and performs AFC so as to compensate for the frequency offset.

However, since the known symbols after correlation are affected by the cross-correlation of the spreading code and the noise, etc., the above-mentioned conventional receiving apparatus has a known symbol. It is difficult to estimate the amount of phase rotation between bols with high accuracy, and the accuracy of AFC deteriorates. Disclosure of the invention

SUMMARY OF THE INVENTION It is an object of the present invention to provide a receiving apparatus that can accurately estimate the amount of phase rotation between known symbols by suppressing the influence of cross-correlation of a spreading code and the influence of noise, and realize a highly accurate AFC. And an automatic frequency control method.

The purpose is that the transmitting side inserts a known symbol consisting of a spreading code obtained by code shift into the transmission data and multiplexes it, and the receiving side uses the value obtained by adding the correlation values of a plurality of known symbols to obtain the phase rotation amount. Is achieved by estimating BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a diagram showing a slot configuration of data transmitted from a transmission device, FIG. 2 is a block diagram showing a configuration of a conventional reception device,

FIG. 3 is a diagram for explaining a method of generating a spread code of a known symbol part used in the present invention.

FIG. 4 is a diagram illustrating a slot configuration of data transmitted from a base station apparatus that performs wireless communication with a communication terminal apparatus according to Embodiment 1 of the present invention.

FIG. 5 is a block diagram showing the configuration of the communication terminal device according to the above embodiment, FIG. 6 is a diagram showing a delay profile created by the communication terminal device according to the above embodiment,

FIG. 7A is a diagram showing the amount of phase rotation estimated by the communication terminal device according to the above embodiment,

FIG. 7B is a diagram showing the amount of phase rotation estimated by the communication terminal device according to the above embodiment,

FIG. 7C shows the amount of phase rotation estimated by the communication terminal device according to the above embodiment. Figures shown, and

FIG. 8 is a block diagram showing a configuration of a communication terminal device according to Embodiment 2 of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

Here, before starting the description of each embodiment, first, a method of generating a spread code of a known symbol part inserted into transmission data by the transmission side in the present invention will be described with reference to FIG. I do.

In Fig. 3, the length of the basic code is P (chip), and the maximum delay profile length of the radio line is W (chip). In addition, two identical basic codes are arranged in series, the front is a basic code BC1, and the rear is a basic code BC2.

The spreading code Code 1 for the user 1 is created by adding a W portion from the beginning of the basic code BC 2 to the basic code BC 1. Also, the spreading code Code 2 for user 2 is created by removing the W portion from the beginning of the basic code BC1 and adding 2 XW from the beginning of the basic code BC2. That is, the spreading code Code 2 is obtained by moving (shifting) the portion corresponding to the spreading code Code 1 backward by W in the basic codes BC1 and BC2.

Similarly, assuming that the number of users is k, the spreading code Codei for the user i (i = l, 2,..., K) is obtained by removing the (i−1) × W part from the beginning of the basic code BC1. It is created by adding i XW part from the top of the basic code B C2 to the thing. Each spreading code Codei has a length of Lm = P + W (chip).

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, the transmitting side is a base station apparatus and the receiving side is a communication terminal apparatus. In the following description, a delayed wave is not considered. In the following description, the spread code generated by the method shown in FIG. 3 is referred to as “shift code”.

(Embodiment 1)

FIG. 4 is a diagram illustrating a base station that performs wireless communication with a communication terminal apparatus according to Embodiment 1 of the present invention. FIG. 4 is a diagram illustrating a slot configuration of data transmitted from a device. As shown in FIG. 4, a known symbol is inserted at substantially the center of the slot. This known symbol is a spreading code generated by the method shown in FIG. Also, the de-multiplexing section is multiplied by a dispersion code unique to each user.

The base station apparatus multiplexes and transmits a signal having the slot configuration shown in FIG. 4 to each communication terminal apparatus (user) during communication. In addition, the basic code and the shift amount are notified in advance to each communication terminal device by transmitting and receiving the control signal.

FIG. 5 is a block diagram showing a configuration of the communication terminal device according to the present embodiment. FIG. 5 shows the configuration of the receiving side of the communication terminal apparatus, and the configuration of the transmitting side is omitted.

Receiving antenna 101 receives a radio signal transmitted from the base station device. The reception RF section 102 multiplies the reception signal of the reception antenna 101 by a local signal oscillated by an oscillator 123 described later, and converts the frequency of the reception signal to spanned.

The AZD converter 103 performs A / D conversion on the in-phase component (I-ch) of the baseband signal (hereinafter, referred to as “reception paceband signal”) output from the reception RF section 102. Similarly, the 8/0 converter 104 performs A / D conversion on the orthogonal component (Q-ch) of the received spanned signal.

The searcher 105 uses the basic code shown in FIG. 3 to create a delay profile of the known symbol part of the received baseband signal converted to a digital signal, and the power of the correlation value is set to a threshold. (That is, the reception timing of a known symbol) is detected and output to the code number 'type determination unit 106. Further, the searcher 105 calculates the reception timing at the head of the data part based on the reception timing of the known symbol, and outputs it to the correlator 107 and the synchronous detector 110. The code number 'type determination unit 106 determines the number and type of the currently used shift codes based on the reception timing of the known symbols from the searcher 105, and the correlator 108-l ~ N and correlator 1 0 9-l ~ n (where n is The timing of the correlation process is instructed to. The details of the determination of the number of codes and the type in the code number / type determination unit 106 will be described later.

The correlator 107, based on the reception timing of the head of the data portion from the search device 105, receives the data portion of the received paceband signal and a predetermined spreading code (spreading code assigned to its own device). And outputs the data part of the received paceband signal after the correlation processing to the synchronous detector 110.

The correlators 1 08 — 1 to n are correlated values (hereinafter referred to as “symbol first half”) between the known symbol first half of the received baseband signal and the shift code in accordance with the instruction from the code number / type determination unit 106. Partial correlation value ”). Similarly, the correlators 109-1 to n correspond to the correlation value between the latter half of the known symbol of the received baseband signal and the shift code (hereinafter, “ The second half of the symbol).

The synchronous detection unit 110 performs synchronous detection processing on the data part of the received baseband signal after correlation processing based on the reception timing at the head of the data part from the searcher 105, and performs demodulation. 1 Output to 1. The demodulation unit 111 performs demodulation processing on the demodulated portion of the synchronously detected received baseband signal, and extracts received data.

The adder 111 adds the in-phase components of the first half symbol correlation values calculated by the correlators 108-ln to n, respectively. Similarly, the adder 113 adds the orthogonal components of the symbol first half correlation values calculated respectively by the correlators 108-1-n. The adder 114 adds the in-phase components of the second half correlation values of the symbols calculated by the correlators 109-ln to n, respectively. Similarly, the adder 115 adds the orthogonal components of the correlation value of the latter half of the symbol calculated by the correlators 109-ln to n, respectively. The delay unit 1 16 delays the in-phase component of the symbol first-half correlation value added by the adder 1 12 by a predetermined amount, and then outputs the result to the complex correlation operation unit 1 18. Similarly, delay section 117 delays the orthogonal component of the first half correlation value of the symbol added by adder 113 by a predetermined amount, and outputs the result to complex correlation operation section 118. The complex correlation operation unit 118 performs a complex correlation process using the in-phase component of the symbol first half correlation value after the addition and the in-phase component of the symbol second half correlation value after the addition. Further, complex correlation operation section 118 performs a complex correlation process using the orthogonal component of the symbol first half correlation value after addition and the orthogonal component of the symbol second half correlation value after addition.

The phase estimating unit 119 estimates the amount of phase rotation per unit time using the in-phase component and the quadrature component of the correlation value after the complex correlation processing output from the complex correlation calculating unit 118. The details of the estimation of the amount of phase rotation by the phase estimating unit 119 will be described later.

The smoothing unit 120 calculates the frequency offset by smoothing the phase rotation amount estimated by the phase estimating unit 119. The control voltage converter 122 outputs a signal having a predetermined control voltage to be applied to the oscillator 123 to the DZA converter 122 in order to compensate for the calculated frequency offset. The D / A converter 122 converts the signal output from the control voltage converter 122 into an analog signal. The oscillator 123 oscillates a local signal having a frequency corresponding to the voltage of the output signal of the DZA converter 122. Next, the operation of the AFC in the communication terminal device shown in FIG. 3 will be described. The radio signal transmitted from the base station apparatus is received by the receiving antenna 101, and is multiplied by the received RF unit 102 by the local signal oscillated by the oscillator 123 to obtain the baseband frequency. Is converted.

The in-phase component of the received baseband signal is converted to a digital signal by the A / D converter 103, and the quadrature component of the received paceband signal is converted to the digital signal by the octave converter 104. Is converted to a video signal. The received paceband signal converted to the digitized signal is output to searcher 105, correlator 107, correlator 108-ln and correlator 109-ln.

In the searcher 105, a delay profile of a known symbol part of the received baseband signal converted into a digital signal is created by the basic code shown in FIG. 3 above, and the reception timing of the known symbol is detected. The number and type of shift codes currently used are determined by the code number 'type determination unit 106. The correlator 107 correlates the data portion of the received baseband signal with a predetermined spreading code (spreading code assigned to its own device) based on the reception timing at the head of the data portion. Then, the synchronous detection unit 110 performs synchronous detection processing on the data part of the received baseband signal after the correlation processing based on the reception timing at the head of the data part, and the demodulation unit 111 At 1, demodulation processing is performed on the data portion of the synchronously detected received baseband signal, and the received data is extracted.

In the correlators 108-ln, the correlation value of the first half of the symbol is calculated from the second half of the known symbol of the received baseband signal and the shift code. Similarly, in the correlators 109-1 to n, the symbol second half correlation value is calculated from the known symbol second half of the received paceband signal and the shift code. The in-phase and quadrature components of the first half symbol correlation values calculated by each correlator 1 08—l to n are added by the adders 1 12 and 1 13 and the delay units 1 16 and 1 1 A predetermined amount is delayed by 7. The in-phase and quadrature components of the second half correlation value of the symbol calculated by each correlator 109-l to n are added by adders 114 and 115. The complex correlation operation unit 118 calculates the quadrature component of the symbol first-half correlation value after addition by using the in-phase component of the symbol first-half correlation value after addition and the in-phase component of the symbol second-half correlation value after addition. A complex correlation process is performed by using and the orthogonal component of the correlation value of the latter half of the symbol after the addition.

Then, the phase estimator 1 19 estimates the amount of phase rotation per unit time based on the in-phase and quadrature components of the correlation value after the complex correlation processing, and the smoothing unit 120 smoothes the amount of phase rotation. To calculate the frequency offset. The calculated frequency offset is output to the control voltage converter 121.

In the control voltage converter 122, a signal having a predetermined control voltage is output to the DZA converter 122 so as to compensate for the calculated frequency offset, and is converted into an analog signal. Output to 3. In the oscillator 13, a local signal having a frequency according to the voltage of the output signal of the DZA converter 122 is oscillated. 7

10 Next, the details of the determination of the code number and the type in the code number / type determination unit 106 will be described with reference to the diagram showing the delay profile in FIG. FIG. 6 is a diagram showing a delay profile created by the communication terminal device according to the present embodiment. In FIG. 6, the horizontal axis is time, and the vertical axis is power.

When the base station apparatus multiplexes the data shown in FIG. 4 to a plurality of communication terminal apparatuses, the receiving side of the communication terminal apparatus uses the basic code to generate the known symbol part of the received baseband signal. When a delay profile is created, peaks exceeding the threshold are detected by the number of communication terminals currently communicating.

Then, when the base station apparatus is performing wireless communication with the communication terminal apparatus using the shift code Code i, the time at which the base station apparatus transmitted the data is set to 0, and the time is calculated from the time (i-1) XW. A peak exceeding the threshold appears in the range of the time zone T i less than i × W.

For example, in the case of FIG. 6, peaks Pl and P3 that exceed the threshold in the range of T1 and T3 appear, so the base station apparatus uses the shift code Codel and the shift code Code3. It can be seen that wireless communication is being performed with the communication terminal device. The code number and type determination unit 106 determines the number of communication terminals with which the base station apparatus is currently performing wireless communication based on the number of peaks exceeding the threshold, and determines the time zone to which the peak evening belongs. The base station apparatus determines a shift code used for a known symbol of a transmission signal based on.

Then, in the case of FIG. 6, the code number 'type judging section 106 instructs the correlator 108-8-1 to use the time P1 as the timing of the correlation processing, and instructs the correlator 108-8-2. Time P3 is designated as the timing of the correlation processing. Further, the code number 'type judging section 106 designates the time (Pl + tk / 2) as the timing of the correlation processing to the correlator 109--1, assuming that the length of the known symbol section is tk. Then, the time (P3 + tk / 2) is instructed to the correlator 109-2 as the timing of the correlation processing.

Next, details of the estimation of the amount of phase rotation in the phase estimating unit 1 19 will be described with reference to FIG. This will be described with reference to FIGS. 7B and 7C showing the phase rotation amounts. 7A, 7B, and 7C are diagrams illustrating the amount of phase rotation estimated by the communication terminal apparatus according to the present embodiment. In Figures 7A, 7B, and 7C, the correlation values are represented as vectors on the IQ plane.

In FIG. 7A, vector 201 is a symbol first half correlation value between the known symbol first half of the received paceband signal and the shift code Codel, and vector 202 is the known symbol first half of the received baseband signal. This is the correlation value of the first half of the symbol with the shift code Code 3, and the vector 203 is a composite vector obtained by adding the vector 201 and the vector 202.

In FIG. 7B, vector 211 is the correlation value of the latter half of the symbol of the received baseband signal and the latter half of the symbol with the shift code Code 1, and the vector 211 is the received paceband signal. This is the correlation value between the latter half of the known symbol and the shift code Code 3, and the vector 2 13 is a composite vector obtained by adding the vector 2 11 and the vector 2 12.

Then, in FIG. 7C, the angle difference 0 between the combined vector 203 and the combined vector 213 indicates the amount of phase rotation. The phase estimating unit 119 estimates the amount of phase rotation using a value obtained by adding the correlation values of a plurality of known symbols.

As described above, the transmitting side inserts the known symbol composed of the spread code obtained by the code shift into the transmission data and performs multiplex transmission, whereby the receiving side can calculate the correlation value of a plurality of known symbols.

Here, since the cross-correlation and noise of the spread code affecting the correlated known symbols are random, the correlation values of a plurality of known symbols are added to obtain the cross-correlation of the spread codes in estimating the amount of phase rotation. The effects of correlation and noise are suppressed.

Therefore, the transmitting side inserts a known symbol consisting of a spreading code obtained by code shift into transmission data and multiplexes it, and the receiving side calculates the phase rotation amount using the value obtained by adding the correlation values of a plurality of known symbols. By estimating, between known symbols The amount of phase rotation can be estimated with high accuracy, and highly accurate AFC can be realized.

It is desirable that the number n of the correlators 108-1 to: Q and the correlators 109-1 to n be equal to the number of codes that can be simultaneously communicated. Holds even if the number of codes is smaller than the number of codes. In this case, the code number / type judging section 106 sequentially selects the shift codes having the highest peaks from the currently used shift codes, and selects the correlator 108-l to n and the correlator 109-1. 1 ~! ! Instruct the timing of the correlation processing to.

(Embodiment 2)

Here, in Embodiment 1 described above, when only one communication terminal apparatus is currently communicating with the base station apparatus, the feature of adding the correlation value of the known symbol cannot be utilized, and In addition, since the phase rotation amount is estimated in the first half and the second half of the known symbol portion that are close in time, the estimation accuracy of the phase rotation amount is considered to deteriorate rather than the conventional case.

In the second embodiment, a case will be described in which the correlation value used for estimating the amount of phase rotation is switched according to the number of shift codes currently used in order to solve the above problem.

FIG. 8 is a block diagram showing a configuration of a communication terminal device according to Embodiment 2 of the present invention. Note that, in the communication terminal device shown in FIG. 8, the same components as those of the communication terminal device shown in FIG.

The communication terminal device shown in FIG. 8 differs from the code number / type determination unit 106 of the communication terminal device shown in FIG. 5 in the function of the code number / type determination unit 301. Further, the communication terminal device shown in FIG. 8 has a configuration in which correlators 302, 303 and a switching unit 304 are added, as compared with the communication terminal device shown in FIG.

The searcher 105 detects the timing at which the power of the correlation value exceeds the threshold (that is, the reception timing of the known symbol) and outputs it to the code number / type determination unit 301. 02227

13

The number-of-codes' type determination unit 301 determines the number and type of the currently used shift codes based on the reception timing of the known symbols from the searcher 105. Then, when the number of currently used shift codes is plural, the correlator 1 08— :! ~ N and correlator 1 0 9— 1 ~! ! (N is a natural number of 2 or more) indicates the timing of the correlation processing, and if singular, indicates the timing of the correlation processing to the correlator 302 and the correlation processing to the correlator 303 To execute

Further, the code number / type determining unit 301 controls the switching of the switching unit 304 based on the number of currently used shift codes. Specifically, when the number of shift codes currently used is plural, the adder 1 1 2 and the delay 1 1 6, the adder 1 1 3 and the complex correlation calculator 1 1 8, the adder 1 1 Switching control is performed so that 4 and the delay unit 1 17 and the adder 1 15 and the complex correlation operation unit 1 18 are connected to each other. On the other hand, if the number of currently used shift codes is singular, the correlator 302 and the delay unit 116, the correlator 302 and the complex correlation operation unit 118, and the correlator 303 Switching control is performed so that the delay unit 117 and the correlator 303 are connected to the complex correlation operation unit 118, respectively.

The correlator 302, in accordance with the instruction from the code number / type judging unit 301, calculates the correlation value between the entire known symbol part of the received baseband signal and the shift code (hereinafter, referred to as “the overall symbol correlation value”). Is calculated.

According to the instruction from the code number 'type judging unit 301, the correlator 303 receives the correlation value between the received received signal of the control channel for synchronization and the spread code of the control channel (hereinafter referred to as "control channel"). Correlation value).

The switching unit 304 switches the connection according to the control of the code number / type determining unit 301 described above.

As a result, when the number of currently used shift codes is single, phase estimating section 119 estimates the amount of phase rotation from the angle difference between the overall symbol correlation value and the synchronization control channel correlation value. As described above, by switching the correlation value used for estimating the amount of phase rotation according to the number of currently used shift codes, when the number of shift codes is plural, the same effect as in the first embodiment is obtained. , And stable AFC can be performed even when the number of shift codes is singular.

Here, if a common synchronization control channel is used in all cells, there is a possibility that the amount of phase rotation is erroneously estimated using the control channel of another cell, and in this case, the accuracy of pulling in the frequency offset is large. Will deteriorate. Therefore, by estimating the amount of phase rotation using the synchronization control channel unique to each cell, the stability of the system is improved.

Further, the offset amount of the synchronization control channel with respect to the beginning of the slot differs depending on the cell, and the position of the synchronization control channel may be close in time to the position of the known symbol part. In this case, AFC can be performed with higher accuracy by estimating the amount of phase rotation in the former half and the latter half of the known symbol part as shown in the first embodiment. Therefore, the communication terminal knows the position of the control channel for synchronization before the line is established, and appropriately adjusts the signal used for estimating the amount of phase rotation based on the positional relationship between the position of the control channel for synchronization and the known symbol part. By switching, it is always possible to achieve a certain level of stable AFC.

In addition, by combining the above embodiments with space diversity reception and path diversity reception, more stable and highly accurate AFC can be performed.

Further, in the above embodiments, the transmitting side is described as a base station apparatus and the receiving side is described as a communication terminal apparatus. However, the present invention can be applied even when the receiving side is a base station apparatus and the transmitting side is a communication terminal apparatus. it can.

Further, in each of the above embodiments, a delayed wave is not taken into account for simplicity of description. However, the present invention provides a receiving apparatus having a component for performing channel estimation, RAKE combining, and the like, thereby realizing delay. The above effects can be obtained even in a propagation environment where waves exist. In each of the above embodiments, the correlation value of the known symbol in other time slots is also added to perform a complex correlation operation, and the amount of phase rotation is estimated. The effect of the AFC can be suppressed, and more accurate AFC can be realized. As is clear from the above description, according to the present invention, the correlation values of a plurality of known symbols can be added. The amount of phase rotation can be estimated with high accuracy, and highly accurate AFC can be realized. be able to.

The present specification is based on Japanese Patent Application No. 2000-278193 filed on Sep. 13, 2000. This content is included here. Industrial applicability

INDUSTRIAL APPLICABILITY The present invention is suitable for use in a communication terminal device or a base station device of a CDMA wireless communication system.

Claims

The scope of the claims

1. Correlation value calculation means for calculating a correlation value of one or a plurality of time-multiplexed received signals, phase rotation amount estimation means for estimating a phase rotation amount using an added value of the correlation values, and the phase rotation amount Frequency control means for controlling the frequency of the oscillator so as to compensate for the frequency offset based on the following.

2. The correlation value calculating means calculates a correlation value using the known symbol portion of the received signal into which a known symbol including a part of a predetermined basic code is inserted.

3. Search means for calculating a first correlation value which is a correlation value between a received signal into which a known symbol consisting of a part of a predetermined basic code has been inserted and the basic code, and 3. The receiving apparatus according to claim 2, further comprising: determining means for determining the number and type of known symbols time-multiplexed based on the number of first correlation values and the time zone to which the reception timing belongs.

4. The correlation value calculation means is a correlation value between the received signal portion in which the first half of the known symbol is inserted and the known symbol determined to be time-multiplexed by the determination means, and a second correlation value and the known symbol. Calculating a third correlation value which is a correlation value between the latter half of the known symbol and the determined known symbol, and the phase rotation amount estimating means calculates a sum of the second correlation value and the third correlation value. 4. The receiving device according to claim 3, wherein the phase rotation amount is estimated from the phase difference.

5. The correlation value calculating means calculates the correlation value between the fourth correlation value and the received signal, which are correlation values between the received signal portion where the known symbol is inserted and the known symbol determined to be time-multiplexed by the determination means. A fifth correlation value, which is a correlation value with the spreading code of the control channel, is calculated.If the number of time-multiplexed known symbols is 1, the fourth correlation value and the fifth correlation value are calculated. 4. The receiving device according to claim 3, wherein the amount of phase rotation is estimated from a phase difference from the correlation value.

6. The receiving apparatus according to claim 5, wherein the correlation value calculating means calculates a fifth correlation value using a cell-specific control channel.

7. Even if the number of time-multiplexed known symbols is one, the phase rotation amount estimating means may determine that the second correlation value and the second correlation value are equal when the control channel and the known symbols are temporally close to each other. (3) Claims for estimating the amount of phase rotation from the phase difference with the correlation value

The receiving device according to 5.

8. A communication terminal device equipped with a receiving device, wherein the receiving device uses a correlation value calculating unit that calculates a correlation value of one or a plurality of time-multiplexed received signals, and an addition value of the correlation value. Phase rotation estimating means for estimating the amount of phase rotation, and frequency control means for controlling the frequency of the oscillator so as to compensate for the frequency offset based on the amount of phase rotation.

9. A base station apparatus for transmitting a known symbol including a part of a predetermined basic code to data and transmitting the data to the communication terminal apparatus according to claim 8.

10. A base station device equipped with a receiving device, wherein the receiving device calculates a correlation value of one or a plurality of time-multiplexed received signals, and calculates an added value of the correlation value. A phase rotation amount estimating means for estimating a phase rotation amount by using the same; and a frequency control means for controlling a frequency of an oscillator so as to compensate for a frequency offset based on the phase rotation amount.

11. A communication terminal device for inserting a known symbol consisting of a part of a predetermined basic code into data and transmitting the data to a base station device according to claim 10.

1 2. Calculate a first correlation value that is a correlation value between a received signal in which a known symbol including a part of a predetermined basic code is inserted and the basic code, and calculate a first correlation value exceeding a predetermined threshold value The number and type of known symbols time-multiplexed are determined based on the number of received symbols and the time zone to which the reception timing belongs, and it is determined that the first half of the known symbols is time-multiplexed with the received signal portion in which the known symbols are inserted. A second correlation value that is a correlation value between the obtained known symbol and a third correlation value that is a correlation value between the second half of the known symbol and the determined known symbol, and sums up the second correlation value. The amount of phase rotation is estimated from the phase difference between the result and the result of adding the third correlation value, and the frequency of the oscillator is controlled so as to compensate for the frequency offset based on the amount of phase rotation. Automatic frequency control method.