JP2002300084A - Channel estimate device, and radio base station unit provided with it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a channel estimate device that does not prolong the processing time without deteriorating the reception performance even in the case of an initial state such as start of communication or in the case of switching of a delay detection interval. SOLUTION: A frequency offset detection section 2041 of a phase rotation detection circuit 204 detects a frequency offset by using an inverse spread signal of a received signal and an fD detection section 2042 detects an fD (a maximum Doppler frequency due to fading fluctuations) by using the frequency offset. A detection monitor 206 monitors the frequency offset detection period or the frequency offset detection/fD detection period. The detection monitor circuit 206 applies switching control to a switch 210 on the basis of the monitor result. For this period, a statistic processing result (tentative fD) is set as an initial value of the fD. A weight coefficient calculation circuit 209 calculates a weight coefficient α by using the fD detection result or the statistic processing result and outputs the weight coefficient α to a weight adder circuit 203. Then the weight adder circuit 203 uses the weight coefficient α to conduct the WMSA(Weighted Multi-Symbol Averaging) thereby outputting a channel estimate value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a digital radio communication system, and more particularly to a CDMA (Code Division Multiple A).
The present invention relates to a channel estimation device used in the ccess) method and a radio base station device provided with the same.

[0002]

2. Description of the Related Art Digital wireless communication systems, especially CDs
In the MA system, a method of weighting and averaging pilot symbols of a plurality of slots (WMSA: Weight) in order to improve reception performance on the receiving apparatus side
Technologies such as ed Multi-Symbol Averaging, delay averaging time constant, and phase rotation detection are employed, and in these technologies, various parameters are set.

For example, phase rotation detection and WMSA will be described with reference to FIG. In the conventional channel estimation device shown in FIG. 7, the frequency offset detection result detected by the frequency offset detection unit 7011 of the phase rotation detection circuit 701 is output to the phase rotation correction circuit 702 and the detection monitoring circuit 703, and the maximum Doppler frequency (fD ) Detector 701
The fD detection result detected in step 2 is a weight coefficient calculation circuit 704
And output to the detection monitoring circuit 703.

The phase rotation correction circuit 702 corrects the phase rotation using the frequency offset detection result, and outputs the correction result to a weighting addition circuit (not shown). The detection monitoring circuit 703 monitors the detection state from the frequency offset detection result and the fD detection result, and calculates the weighting coefficient using the fD detection result, the weighting factor from the weighting factor calculation circuit 704 and the fixed weighting factor (fD) 706. The switch 705 for changing over is controlled. The output from the weighting coefficient calculation circuit 704 or the fixed weighting coefficient is output to the weighting addition circuit.

[0005] The weighting addition circuit performs WMSA processing using the correction result output from the phase rotation correction circuit 702 and a weighting coefficient or a fixed weighting coefficient to output a channel estimation value.

In the channel estimating apparatus having the above configuration,
For example, at the start of communication, during the detection of a new frequency offset, or during the detection of fD after the detection of the frequency offset,
Since it is impossible to determine the weight coefficient, a unique fixed weight coefficient independent of fD is used.

If these parameters are not controlled in accordance with the propagation environment (usage environment), the reception sensitivity may be degraded. For example, in the initial state, the state of communication is not stable, so if the above-described control is performed with the parameters fixed, there is a possibility that reception sensitivity may be degraded.

Here, the detection of the phase rotation in the initial state will be described as an example. The phase rotation detection is a method of detecting the maximum Doppler frequency (fD) due to carrier frequency offset and fading fluctuation from a received signal with high accuracy. The detection is performed by detecting fD based on the result of the frequency offset detection in the phase rotation detection circuit. Further, a weighting factor is determined based on the detection result, and the pilot symbols of a plurality of slots are weighted and averaged using the weighting factor.

Therefore, in an initial state such as the start of communication, it is impossible to determine the weight coefficient during the frequency offset detection or during the fD detection after the frequency offset detection. Therefore, a unique fixed weighting factor (fD) is used.

[0010]

However, if the fixed weighting factor is different from the actual fD, the channel estimation cannot be performed accurately using the fixed weighting factor, and the receiving sensitivity is reduced. May cause temporary degradation. For example, as shown in FIG. 8, when the weight coefficient is optimal (no difference from the actual fD) and when the weight coefficient is inappropriate (different from the actual fD), the same error rate (in FIG. 8, To get BLER (Block Error Rate))
The transmission power must be increased by about 4 dB. Regarding a study of weighting factors and fD (moving speed), "Effects of demodulation using multiple channel estimates in parallel in W-CDMA"
B-5-3 (NTT Mobile Communications Network Inc .: Usuda et al.).

As described above, when the actual fD is different from that of the actual fD, the channel cannot be accurately estimated. Therefore, it is necessary to detect the fD again, which consumes processing time. In addition, since synchronization is performed with the fixed weight coefficient before synchronization is established, if the weight coefficient is inappropriate, correct reception cannot be performed and it may take more time until synchronization is established.

The present invention has been made in view of such a point, and even in an initial state such as the start of communication, an appropriate fD can be used for calculating a weight coefficient, so that the reception performance is not degraded, and It is an object of the present invention to provide a channel estimating device in which processing time is reduced and a wireless base station device provided with the same.

[0013]

A channel estimating apparatus according to the present invention comprises: a frequency offset detecting means for detecting a phase rotation caused by a carrier frequency offset by using a received signal;
Using the received signal, a maximum Doppler frequency detecting means for detecting a phase rotation based on a maximum Doppler frequency, and a statistical process of obtaining a temporary maximum Doppler frequency by performing a statistical process on the maximum Doppler frequency or the moving speed obtained from the maximum Doppler frequency Means for monitoring the detection period of the maximum Doppler frequency, and based on the monitoring result, monitoring means for switching between the detected maximum Doppler frequency and the temporary maximum Doppler frequency; and the detected maximum Doppler frequency or the temporary maximum Doppler frequency. , And weighted addition means for performing weighted addition using the frequency offset and outputting a channel estimation value.

According to this configuration, even in the initial state such as the start of communication, an appropriate fD according to the use environment can be used for calculating the weight coefficient, so that the weighted addition can be performed appropriately. It is possible to output an accurate channel estimation value. As a result, the receiving performance of the receiving device can be improved.

[0015] In the channel estimation apparatus of the present invention, in the above configuration, the statistical processing means may use, as an example, a provisional maximum using a frequency interval having the highest detection frequency when the maximum Doppler frequency is divided at a predetermined frequency interval. A configuration for obtaining the Doppler frequency is employed.

According to this configuration, the maximum Doppler frequency considered appropriate for the installation environment can be obtained by the statistical processing.

The channel estimating apparatus of the present invention, in the above configuration, includes a synchronization establishment monitoring means for monitoring whether synchronization has been established, and the statistical processing means detects the synchronization based on the monitoring result of the synchronization establishment monitoring means. A configuration is adopted in which a temporary maximum Doppler frequency is obtained using another frequency section having the highest frequency.

According to this configuration, when synchronization has not been established, the temporary maximum Doppler frequency can be changed, so that the time until synchronization is established can be shortened.

The channel estimating apparatus of the present invention employs a configuration for performing control according to the propagation environment (usage environment) in the above configuration.

According to this configuration, the propagation environment (use environment)
, It is possible to improve the estimation accuracy, reduce the processing time, and suppress the temporary deterioration of the reception sensitivity even in the initial state such as the start of communication.

The channel estimation apparatus of the present invention employs a configuration in which statistical processing is performed in consideration of a temporal element in the above-described configuration, and a tentative Doppler frequency estimated by the statistical processing is obtained.

According to this configuration, for example, in the vicinity of a highway, fD is expected to be low because the traveling speed is relatively low in the daytime, and fD is expected to be low in the nighttime because the traveling speed is relatively high.
Since D is expected to be high, we statistically process these,
By performing the estimation process with time, the estimation accuracy can be improved.

A radio base station apparatus according to the present invention includes the above-mentioned channel estimating apparatus. According to this configuration, in a digital wireless communication system, even in an initial state such as the start of communication, it is possible to improve estimation accuracy, reduce processing time, and suppress temporary deterioration in reception sensitivity.

[0024] The radio base station apparatus of the present invention is characterized in that, in the above configuration, the channel estimation apparatus performs processing for each directional antenna or each sector. According to this configuration,
For example, fD is expected to be relatively high in an antenna or sector having directivity in a range including a road, and fD is relatively low in an antenna or sector having directivity in a range including only private houses not including a road. Therefore, control according to the use environment can be performed.

In the channel estimation method according to the present invention, a frequency offset detecting step of detecting a phase rotation caused by a carrier frequency offset using a received signal, and a maximum Doppler detecting a phase rotation caused by a maximum Doppler frequency by using the received signal Frequency detection step, a statistical processing step of obtaining a temporary maximum Doppler frequency by statistical processing about the maximum Doppler frequency or the moving speed obtained from the maximum Doppler frequency, monitoring the detection period of the maximum Doppler frequency, based on the monitoring result A monitoring step of switching between the detected maximum Doppler frequency and the provisional maximum Doppler frequency, and performing weighted addition using the detected maximum Doppler frequency or the provisional maximum Doppler frequency and the frequency offset to output a channel estimation value. Weighting and adding step To Bei.

According to this method, an appropriate fD according to the installation environment can be used for calculating the weighting factor even in an initial state such as the start of communication, so that weighting addition can be performed appropriately. It is possible to output an accurate channel estimation value. As a result, the receiving performance of the receiving device can be improved.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION Since a radio base station apparatus (BTS) is assumed not to be frequently relocated due to equipment, propagation when a moving speed between the BTS and a communication terminal apparatus (MS) is somewhat biased. The environment (usage environment) is considered to be unique. For example, when the mobile terminal is installed in a place such as a highway or a railroad, the movement of the MS is fast, so that the fD is high.
It is assumed that the ratio of the detection result of the low fD becomes high because the MS moves at a low speed (walking) when installed in a place such as a downtown area.

The present inventor has made the present invention by paying attention to the above points. That is, the gist of the present invention is to set the initial value of the fD detection value based on the statistical processing result of the fD detection value, thereby improving the estimation accuracy and reducing the processing time even in the initial state such as the start of communication. Another object of the present invention is to suppress the temporary deterioration of the receiving sensitivity. Further, according to the present invention, it is possible to speed up synchronization even before synchronization is established.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a block diagram showing a configuration of the radio base station apparatus according to the embodiment of the present invention. Although the base station shown in FIG. 1 describes a case where the number of paths for RAKE combining is two, the present invention can also be applied to a case where the number of paths for RAKE combining is three or more. Also, in the base station shown in FIG. 1, only one user's sequence is shown for simplicity of description. Therefore, the present invention can be similarly applied to a series of a plurality of users.

A signal transmitted from a communication terminal as a communication partner is received by a radio receiving circuit 103 from an antenna 101 via a duplexer 102. The wireless receiving circuit 103 performs a predetermined wireless receiving process (down conversion, A / D conversion, etc.) on the received signal, and outputs the signal after the wireless receiving process to the correlators 104 and 105. The signal after the wireless reception processing is output to search circuit 106.

In the correlator 104, the data portion (DPDCH (Dedicated Physical Data)
Channel)) is subjected to despreading processing using the spreading code used in the spread modulation processing at the communication terminal as the communication partner, and is applied to the delay unit 1071 of the synchronous detection circuit 107 and the delay unit 1081 of the synchronous detection circuit 108. Output. Correlator 105
Then, the pilot part (known signal) of the signal after the radio reception processing is subjected to despreading processing using the spreading code used in the spread modulation processing at the communication terminal as the communication partner, and the channel of the synchronous detection circuit 107 is It outputs to the estimation circuit 1072 and the channel estimation circuit 1082 of the synchronous detection circuit 108.
The search circuit 106 synchronizes the paths for performing the despreading process and synchronizes the timing information with the correlators 104 and 1.
Output to 05. Correlator 104 and correlator 105 perform despreading processing based on the timing information from search circuit 106.

Channel estimation circuit 1 of synchronous detection circuit 107
At 072, channel estimation is performed using the pilot portion of the received signal, and the channel estimation value is output to multiplier 1073. The multiplier 1073 multiplies the data portion of the received signal, the timing of which has been corrected by the delay unit 1071, by the channel estimation value. Thus, synchronous detection is performed. The signal after the synchronous detection is output to RAKE combiner 109.

Channel estimation circuit 1 of synchronous detection circuit 108
In 082, channel estimation is performed using the pilot portion of the received signal, and the channel estimation value is output to multiplier 1083. The multiplier 1083 multiplies the data portion of the received signal, the timing of which has been corrected by the delay unit 1081, by the channel estimation value. Thus, synchronous detection is performed. The signal after the synchronous detection is output to RAKE combiner 109.

The RAKE combiner 109 RAKE-combines the outputs from the synchronous detection circuit 107 and the synchronous detection circuit 108 and outputs the RAKE-combined signal to the demodulation circuit 110. The demodulation circuit 110 performs demodulation processing on the RAKE-combined signal to obtain received data.

The transmission data is output to the spreading circuit 112 after being modulated by the modulation circuit 111. Diffusion circuit 1
In 12, spread modulation processing is performed on the data after the modulation processing using a predetermined spreading code, and the data after the spread modulation processing is output to the radio transmission circuit 113. Wireless transmission circuit 113
Then, predetermined radio transmission processing (D / A conversion, up-conversion) is performed on the data after the spread modulation processing. The signal subjected to the wireless transmission processing is transmitted to the antenna 1 via the duplexer 102.
01 is transmitted to the communication terminal that is the communication partner.

Next, the configuration of the channel estimation circuits 1072 and 1082 of the synchronous detection circuits 107 and 108 will be described. FIG. 2 is a block diagram showing a configuration of a channel estimation circuit of the wireless base station device shown in FIG.

The multiplier 201 multiplies the signal after despreading processing by a pilot pattern (PL pattern), eliminates data modulation components by the PL pattern to make them in-phase, and outputs the multiplication result to the in-phase addition circuit 202. . The in-phase addition circuit 202 performs in-phase addition on the multiplication result to obtain a channel estimation value in slot units. This channel estimation value is output to the weighting addition circuit 203.

On the other hand, the signal after the despreading processing is output to the phase rotation detection circuit 204. The phase rotation detection circuit 204 includes a frequency offset detection unit 2041 for obtaining a frequency offset from the signal after the despreading process, and an fD detection unit 2042 for obtaining the maximum Doppler frequency (hereinafter, Doppler frequency or fD) from the signal after the despreading process. Having. That is, the phase rotation detection circuit 204 individually detects the frequency offset and the maximum Doppler frequency.

The frequency offset detection result (the amount of phase rotation corresponding to the frequency offset) detected by the frequency offset detection unit 2041 is output to the phase rotation correction circuit 205 and the detection monitoring circuit 206. Also, the fD detection unit 20
The maximum Doppler frequency (the amount of phase rotation corresponding to fD) detected at 42 is output to the detection monitoring circuit 206 and the statistical processing circuit 207. The detection monitoring circuit 206 monitors whether or not the fD detection result is output, and controls switching of the switch 210 based on the monitoring result.

The phase rotation correction circuit 205 calculates a phase rotation correction value △ θ for each symbol or slot based on the phase rotation amount of the frequency offset, and outputs the phase rotation correction value △ θ to the weighting addition circuit 203. I do.

The statistical processing circuit 207 performs statistical processing of the fD detection result of the phase rotation detection circuit 204 and outputs the statistical processing result to the switch 210. Further, the synchronization state monitoring circuit 208 monitors whether or not the synchronization is established by a preset time, and compares the monitoring result with the statistical processing circuit 2.
07.

The weighting coefficient calculation circuit 209 calculates a weighting coefficient (α) according to the fD detection value or the result of the statistical processing circuit 207, and applies the weighting coefficient α to the weighting addition circuit 2
03 is output. For the calculation of the weight coefficient, a determination table in which communication quality and fD are associated may be prepared, and the weight coefficient may be obtained by referring to the determination table according to the communication quality.

The weighting addition circuit 203 uses the phase rotation correction value △ θ from the phase rotation correction circuit 205 and the weighting coefficient α from the weighting coefficient calculation circuit 209 to weight and add the channel estimation value in slot units over a plurality of slots. I do. In this way, a slot average channel estimation value is obtained from the channel estimation values weighted and added over a plurality of slots. This channel estimation value is used for synchronous detection processing.

The base station apparatus shown in FIG.
A digital wireless communication system based on the CDMA system is configured by the communication terminal device shown in FIG. 3, and wireless communication is performed by the base station shown in FIG. 1 and the communication terminal device shown in FIG. Next, this communication terminal device will be described with reference to FIG.

FIG. 3 is a block diagram showing a configuration of a communication terminal apparatus for performing radio communication with a radio base station apparatus according to an embodiment of the present invention. In the communication terminal shown in FIG.
The case where the number of paths to be KE-combined is 1 will be described.
The present invention can be applied to a case where the number of passes to be RAKE-combined is two or more.

A signal transmitted from a base station as a communication partner is received by a radio receiving circuit 303 from an antenna 301 via a duplexer 302. The wireless reception circuit 303 performs predetermined wireless reception processing on the received signal, and outputs the signal after the wireless reception processing to the correlator 304 and the search circuit 307.

The correlator 304 performs despreading processing on the signal after the radio reception processing using the spreading code used in the spread modulation processing at the communication terminal as the communication partner, thereby performing channel estimation, synchronous detection, and synthesis. Output to the circuit 305. Correlator 3
04 performs despreading processing based on the timing information from the search circuit 307. The channel estimation / synchronous detection / synthesis circuit 305 performs channel estimation by using a pilot portion (known signal) of the signal after the radio reception processing to obtain a channel estimation value, and calculates the channel estimation value of the signal after the radio reception processing. The data part is multiplied to perform synchronous detection. further,
The channel estimation / synchronous detection / combining circuit 305 performs RAKE combining using the signal after the synchronous detection.

The signal after RAKE synthesis is applied to a demodulation circuit 306.
Is output to The demodulation circuit 306 performs demodulation processing on the RAKE-combined signal to obtain received data.

After the transmission data is modulated by the modulation circuit 308, it is output to the spreading circuit 309. Diffusion circuit 3
In step 09, spread modulation processing is performed on the data after the modulation processing using a predetermined spreading code, and the data after the spread modulation processing is output to the wireless transmission circuit 310. Wireless transmission circuit 310
Then, a predetermined wireless transmission process is performed on the data after the spread modulation process. The signal subjected to wireless transmission processing is transmitted to the duplexer 302.
Is transmitted from the antenna 301 to the base station, which is the communication partner, via the antenna 301.

The operation of the digital radio communication system having the above configuration, in particular, the operation of channel estimation in the radio base station apparatus will be described.

The frequency offset detection section 2041 of the phase rotation detection circuit 204 detects a frequency offset using the despread signal of the received signal, and the fD detection section 2042 detects fD using the frequency offset. In particular,
The frequency offset detector 2041 detects the frequency offset by performing delay detection and vector synthesis using the despread signal. Further, the fD detection unit 2042 detects fD by further performing delay detection and vector synthesis on the result of the delay detection and the result of the frequency offset detection.

During the frequency offset detection period or the frequency offset detection / fD detection period, the detection monitoring circuit 20
Monitored at 6. The detection monitoring circuit 206 controls switching of the switch 210 based on the monitoring result.

That is, during the frequency offset detection period or the frequency offset detection / fD detection period (period during which the fD detection result is output), the fD detection result is not used.
The switch 210 is switched so as to output the statistical processing result of the statistical processing circuit 207. Therefore, in this period, the statistical processing result (temporary fD) is set as the initial value of fD.

The weighting coefficient calculation circuit 209 calculates the weighting coefficient α using the fD detection result or the statistical processing result, and outputs the weighting coefficient α to the weighting addition circuit 203. Then, the weighting addition circuit 203 performs WMSA using the weighting α and outputs a channel estimation value.

The statistical processing in the statistical processing circuit 207 is performed based on the probability frequency. Note that, in this case, the statistical processing is performed based on a temporal element and a directional element (for each directional antenna,
(Per sector). In other words, time statistics are obtained, the tendency of fD is obtained, and the statistical results are used.

For example, if the vehicle is near an expressway, it is expected that fD is low because the traveling speed is relatively slow in the daytime (detection frequency distribution shown in FIG. 4 (S ₁ )). Since it is relatively fast, fD is expected to be high (detection frequency distribution shown in FIG. 5 (S ₂ )). Also, statistical processing is performed for each directional antenna or each sector. For example, in an antenna or a sector having directivity in a range including a road, fD is expected to be relatively high (a detection frequency distribution shown in FIG. 5 (S ₂ )). It is expected that the fD is relatively low in an antenna or sector having a directivity in (a detection frequency distribution shown in FIG. 4 (S ₁ )).

In the statistical processing, as shown in FIG.
The detection frequency for fD is totaled, and as one example, the area S when divided by the frequency interval τ is calculated. And
The frequency region (S _A ) where the area S is the maximum is obtained, and fD ′ (fD of τ / 2) at that time is used as a statistical processing result. Thereby, it is possible to obtain a temporary fD that is considered appropriate according to the installation environment. This can be uniquely calculated even if the detection frequencies are dispersed. Note that this calculation is performed every time the fD detection result is sent,
The estimation accuracy can be improved. In FIG. 6,
S _B denotes an area corresponding to the weighting coefficient fD fixed used in conventional channel estimation device.

The synchronization state monitoring circuit 208 monitors whether or not synchronization is established by a preset time. If synchronization is not established, f is used as a result of the statistical processing.
Considering that the D value is not suitable, fD 'is sequentially switched from the value of the statistical processing to the value having the highest frequency. Specifically, FIG.
As shown in (2), when synchronization cannot be established with the value with the highest frequency (S _A ), the processing is performed by switching fD ′ in order of the value with the highest frequency. Then, when synchronization is established, the fD ′ value after switching is set as an initial value, and the result is added or updated to the statistical processing circuit 207 as one fD detection result.

By doing so, it is possible to increase accurate information as a result of statistical processing, and to further improve the estimation accuracy even in an initial state such as the start of communication.
The processing time can be reduced, the temporary deterioration of the receiving sensitivity can be suppressed, and the synchronization can be speeded up even before the synchronization is established.

As described above, according to the present embodiment, an appropriate fD according to the use environment can be used for calculating the weighting coefficient even in the initial state such as the start of communication, so that the weighted addition can be appropriately performed. And an accurate channel estimation value can be output. This allows
It is possible to improve the receiving performance in the receiving device.

Further, when the synchronization has not been established, the result of the statistical processing can be changed, so that the time until the synchronization is established can be shortened.

The present invention is not limited to the above embodiment, but can be implemented with various modifications.

[0063]

As described above, the channel estimating apparatus of the present invention and the radio base station apparatus having the channel estimating apparatus can set an appropriate fD according to the use environment even in an initial state such as the start of communication. Since it can be used for calculation, it is possible to perform weighted addition appropriately, and to output an accurate channel estimation value. As a result, the receiving performance of the receiving device can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a radio base station apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a channel estimation device according to an embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration of a communication terminal device that performs wireless communication with the wireless base station device according to the embodiment of the present invention.

FIG. 4 is a diagram for explaining a statistical processing circuit in the channel estimation device according to the embodiment of the present invention.

FIG. 5 is a diagram for explaining a statistical processing circuit in the channel estimation device according to the embodiment of the present invention.

FIG. 6 is a diagram for explaining a statistical processing circuit in the channel estimation device according to the embodiment of the present invention.

FIG. 7 is a block diagram showing a configuration of a conventional channel estimation device.

FIG. 8 is a diagram for explaining a problem of a conventional channel estimation device.

[Explanation of symbols]

 101, 301 antenna 102, 302 duplexer 103, 303 radio receiving circuit 104, 105, 304 correlator 106, 307 search circuit 107, 108 synchronous detection circuit 110, 306 demodulation circuit 111, 308 modulation circuit 112, 309 spreading circuit 113, 310 Wireless transmission circuit 1071, 1081 Delay unit 1072, 1082 Channel estimation circuit 202 In-phase addition circuit 203 Weighted addition circuit 204 Phase rotation detection circuit 205 Phase rotation correction circuit 206 Detection monitoring circuit 207 Statistical processing circuit 208 Synchronization state monitoring circuit 209 Weight coefficient calculation Circuit 210 Switch 305 Channel estimation / synchronous detection / synthesis circuit

Claims (8)

[Claims] 1. A frequency offset detecting means for detecting a phase rotation by a carrier frequency offset using a received signal, a maximum Doppler frequency detecting means for detecting a phase rotation by a maximum Doppler frequency using the received signal, Statistical processing means for obtaining a tentative maximum Doppler frequency by statistical processing for the Doppler frequency or the moving speed obtained from the maximum Doppler frequency, and monitoring the detection period of the maximum Doppler frequency, based on the monitoring result, the maximum detected Monitoring means for switching between the Doppler frequency and the provisional maximum Doppler frequency, and weighting addition means for performing weighting addition using the detected maximum Doppler frequency or provisional maximum Doppler frequency and frequency offset to output a channel estimation value, A tea characterized by having Flannel estimation device. 2. The statistical processing means according to claim 1, wherein the statistical processing means obtains a temporary maximum Doppler frequency using a frequency section having the highest detection frequency when the maximum Doppler frequency is divided at a predetermined frequency interval. Channel estimation device. 3. A synchronizing establishment monitoring means for monitoring whether or not synchronization has been established, wherein the statistical processing means is configured to execute another frequency in a frequency section having a highest detection frequency based on a monitoring result of the synchronization establishment monitoring means. 3. The channel estimation apparatus according to claim 2, wherein a temporary maximum Doppler frequency is obtained using the section. 4. The channel estimation device according to claim 1, wherein control is performed according to a propagation environment. 5. The statistical processing means according to claim 1, wherein the statistical processing means performs a statistical processing in consideration of a temporal element, and obtains a tentative Doppler frequency estimated by the statistical processing. Channel estimation device. 6. A radio base station apparatus comprising the channel estimation apparatus according to claim 1. 7. The radio base station apparatus according to claim 6, wherein the channel estimation device performs processing for each directional antenna or each sector. 8. A frequency offset detecting step of detecting a phase rotation by a carrier frequency offset using a received signal, a maximum Doppler frequency detecting step of detecting a phase rotation by a maximum Doppler frequency by using the received signal, A statistical processing step of obtaining a tentative maximum Doppler frequency by statistical processing for the Doppler frequency or the moving speed obtained from the maximum Doppler frequency, and monitoring a detection period of the maximum Doppler frequency, based on the monitoring result, the detected maximum A monitoring step of switching between the Doppler frequency and the tentative maximum Doppler frequency, and a weighted addition step of performing a weighted addition using the detected maximum Doppler frequency or the tentative maximum Doppler frequency and a frequency offset to output a channel estimation value, A tea characterized by having Flannel estimation method.