JP2003258925A - Radio receiving device and doppler frequency detecting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect a Doppler frequency with high precision while suppressing an increase in the quantity of arithmetic operations even for a signal which is transmitted in bursts. <P>SOLUTION: A delay detection part 1061 performs delay detection by using the result obtained through in-phase addition by an in-phase addition part 105. Delay detection results are outputted to an in-phase addition part 1062. The in-phase addition part 1062 performs in-phase addition of the delay detection results. The in-phase addition result is outputted to a frequency offset correction part 1063, where frequency offset correction is performed. The frequency offset correction result is outputted to an I-component decision part 1064. The I- component decision part 1064 decides fD by using the frequency offset-corrected in-phase addition result. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital wireless communication system, and more particularly to a CDMA (Code Division Multiple A).
The present invention relates to a wireless receiver and a Doppler frequency detecting method used in a system.

[0002]

Digital radio communication systems, especially CDs
Doppler frequency detection is performed in MA systems. Examples of the method for detecting the amount of phase rotation used for detecting the Doppler frequency include a method using a phase rotation angle, a method using an inner product calculation, and a method using differential detection.

As a method of using the phase rotation angle, "Mitsubishi Electric: Nagayasu et al." Frequency offset correction method in DS-CDMA receiver "1999 IEICE General Conference
B-5-123 ”. This method calculates the phase rotation angle between slots using the formula shown below,
The phase rotation amount is obtained by averaging the detected angles with an IIR (Infinite Impulse Response) filter.

[Equation 1] However, since tan ^-1 is used for the angle calculation, the calculation amount is large and the impact on the hardware scale is large. Further, there is a problem that only the angle is focused and the average of the detected angles is used, and the reliability of each detected angle is not taken into consideration.
That is, the reliability of the channel estimation value (estimated transmission characteristic) in the m slot, that is, the received signal level in that slot, or the magnitude of the differential detection output depending on it is not taken into consideration. If the desired wave signal level is low (or the desired signal-to-interference signal ratio is low), the received signal is greatly affected by noise, and thus the reliability of the detection angle in the differential detection output is low.

As a method using the inner product, "NTT DoCoM
o: Ando et al. “Doppler frequency detection using pilot symbols” 2000 IEICE General Conference B-5-5
There is a method disclosed in “9”. This method detects fD (Doppler frequency) by normalizing the channel estimation value for each slot, then calculating the inner product and averaging. However, this method does not consider the effect of frequency offset. Further, this method has a problem that the reliability of the estimated value is not taken into consideration because the estimated value of each channel is normalized and the inner product is obtained as in the above method.

As a method for solving the problems of the above two conventional examples, "Kanemoto, Hayashi, Miya" Phase rotation detection device and radio base station device including the same "Japanese Patent Application No. 2000-267532.
There is a method disclosed in. In this method, first,
After in-phase addition of the despread signal of the pilot (hereinafter abbreviated as PL) signal which is a known signal, differential detection is performed using this in-phase addition result. Then, frequency offset correction is performed on the differential detection result for each differential detection process. As a result, the differential detection result becomes as shown in FIG.
In FIG. 6, the horizontal axis is the I axis and the vertical axis is the Q axis. The reason why the differential detection results appear vertically above and below the I axis is that the phase rotations occur in opposite directions.

Next, as shown in FIG. 6B, the signal space diagram is folded around the I (in-phase) axis of the IQ plane, that is, the Q (quadrature) component is inverted. Then, the results of folding back are averaged (added) to obtain the angle (θ) of the phase point. The angle of this phase point is related to the Doppler frequency. The higher the Doppler frequency, the larger the angle, and the lower the Doppler frequency, the smaller the angle. Therefore, the Doppler frequency is detected from the angle of the phase point by referring to the table in which the angle of the phase point and the Doppler frequency are associated with each other.

[0007]

However, according to the conventional method, when averaging the folded results, sufficient detection accuracy cannot be obtained unless the averaging length is long to some extent. Therefore, PRACH (Physical Random Access)
When a Doppler frequency is detected using a burst-like signal such as Channel), there are many detection errors and it cannot be applied.

Further, in the conventional method, reception SIR (Signal to Interference Rati
Due to o), the angle of the phase point is detected differently even if the Doppler frequency is the same. That is, the accuracy of the differential detection result before folding back is deteriorated due to noise or interference (the circle showing the differential detection result in FIG. 6A becomes large), and the differential detection result is centered on the I axis. If the circle spreads over the I-axis when folded back, the detected angle increases due to the folding back. In particular, when the Doppler frequency is low and the angle of the phase point at the center of the differential detection result is small, the influence of noise and interference is large. Thus, even if the Doppler frequency is the same, if the angles of the phase points are detected differently, accurate Doppler frequency detection cannot be performed. In this case, it is necessary to use a determination table or the like according to the received SIR.

Similarly, when the spread of the delay detection result crosses the I axis, the spread of the delay detection result does not become a circular shape by folding back, so that the effect of the in-phase addition becomes small.
That is, the in-phase addition result does not easily approach the center of the spread circle of the differential detection result, and the average of the long section is necessary for accurate determination.

Further, according to the conventional method, it is necessary to make the differential detection result symmetric with respect to the I axis before folding back, so that it is necessary to correct the frequency offset every time the differential detection is performed, and the amount of calculation is increased. There is also the problem that there are many.

The present invention has been made in view of the above points, and it is possible to detect a Doppler frequency with high accuracy while suppressing an increase in the amount of calculation even for a signal transmitted in bursts. An object is to provide an apparatus and a Doppler frequency detection method.

[0012]

A radio receiving apparatus according to the present invention comprises a delay detection means for performing delay detection on a known signal included in a received signal, and an in-phase addition means for performing in-phase addition on the result of the delay detection. A determination unit that determines the Doppler frequency based on the in-phase component on the in-phase-quadrature axis in the signal space diagram with respect to the in-phase addition result is adopted.

With this configuration, the Doppler frequency detection can be performed on the result after the in-phase (vector) addition of the differential detection results by the amplitude and the sign of the in-phase component, and it is not necessary to obtain the angle. Can be reduced. In addition, by performing in-phase addition without folding back the differential detection results of signals at each reception timing, it is not related to the reception SIR, so there is no need to use a determination table or the like according to the reception SIR, and the amount of calculation and the circuit scale are reduced. it can. Further, by using differential detection, maximum ratio combining is achieved, and since there is no aliasing, the effect of in-phase addition is great, and the Doppler frequency can be detected with high accuracy. Furthermore, since the frequency offset correction may be performed after the in-phase addition of the differential detection results, the number of corrections can be reduced and the amount of calculation can be reduced.

In the radio receiving apparatus according to the present invention having the above-mentioned configuration, the judging means is the in-phase signal in the signal space diagram.
The configuration is such that Doppler frequency determination is performed by the sign of the in-phase component on the orthogonal axis.

According to this structure, since the normalizing circuit and the threshold value judging circuit are unnecessary, the circuit scale can be reduced. Also, since the angle of the phase point is determined to be 90 °,
Since the change amount of the in-phase component with respect to the angle is large, it is possible to make an accurate determination.

The radio receiving apparatus of the present invention adopts a configuration in which the Doppler frequency determination is performed in a plurality of stages by changing the delay detection interval in the above configuration.

According to this configuration, the Doppler frequency can be determined at a desired Doppler frequency, so that it is possible to detect a plurality of Doppler frequencies more accurately.

The radio receiving apparatus of the present invention has the above-mentioned configuration and is provided with a channel estimation means for performing channel estimation based on the Doppler frequency determination result.

With this configuration, since the coherent detection can be performed using the channel estimation value obtained according to the Doppler frequency, highly accurate channel estimation is performed even when the Doppler frequency, that is, the moving speed changes. Therefore, the synchronous detection can be performed with high accuracy.

The radio receiving apparatus of the present invention has a configuration in which the received signal is a signal transmitted in a burst in the above configuration.

According to this configuration, it becomes possible to detect the Doppler frequency using the signal transmitted in burst.

A radio base station apparatus of the present invention comprises the above radio receiving apparatus. With this configuration, accurate Doppler frequency detection can be performed, and the accuracy of processing that is affected by the Doppler frequency can be improved.

A radio mobile station apparatus of the present invention is characterized by including the radio receiving apparatus. With this configuration, accurate Doppler frequency detection can be performed, and the accuracy of processing that is affected by the Doppler frequency can be improved.

The Doppler frequency detecting method of the present invention comprises: a differential detection step of performing differential detection on a known signal included in a received signal; an in-phase addition step of adding in-phase the result of the differential detection; and an in-phase addition result. On the other hand, the determination step of performing the Doppler frequency determination based on the in-phase component on the in-phase-quadrature axis in the signal space diagram.

According to this method, it is possible to detect the Doppler frequency of the result after the in-phase (vector) addition of the differential detection results by the amplitude and the sign of the in-phase component, and it is not necessary to calculate the angle. Can be reduced. In addition, by performing in-phase addition without folding back the differential detection results of signals at each reception timing, there is no need to use a determination table or the like according to the reception SIR, and the amount of calculation and the circuit scale are reduced. it can. Also, by using differential detection, maximum ratio combining is achieved, and since there is no aliasing, the effect of in-phase addition is large, the noise suppression effect is high, and the Doppler frequency can be detected accurately. Furthermore, since the frequency offset correction may be performed after the in-phase addition of the differential detection results, the number of corrections decreases,
The amount of calculation can be reduced.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. (Embodiment 1) FIG.1 is a block diagram showing a configuration of a radio receiving apparatus according to Embodiment 1 of the present invention.

The radio signal is received by the radio receiving section 102 via the antenna 101. The radio reception unit 102 performs a predetermined radio reception process (for example, down conversion or A / D conversion) on the uplink signal, and outputs a PL (pilot) signal that is a known signal from the signals after the radio reception process. The data is output to the PL despreading unit 103, and the data is output to the data despreading unit 108.

The PL despreading unit 103 performs despreading processing on the PL signal using the spreading code used on the communication terminal side, and the signal after the despreading processing (the despreading signal) is sent to the quadrant correction unit 104. Output.

The quadrant correction unit 104 corrects the despread signal of the PL signal to which the phase rotation is added due to fading or the like to the original quadrant of the PL signal (quadrant on the IQ plane in the signal space diagram). The despread signal after the quadrant correction is output to the in-phase addition unit 105.

The in-phase addition section 105 performs in-phase addition on the despread signals after quadrant correction at predetermined intervals, and the in-phase addition result is the fD detection section 106 and the channel estimation section 10.
7 and the frequency offset detector 112. The frequency offset detection unit 112 detects the frequency offset by performing in-phase addition on the differential detection results, and outputs the frequency offset to the fD detection unit 106 and the channel estimation unit 107.

The fD detector 106 detects fD (Doppler frequency) using the in-phase addition result. The detected fD is output to channel estimation section 107. Note that f
The D detection will be described later with reference to FIG. The channel estimation section 107 performs channel estimation and frequency offset correction using the in-phase addition result based on the detected fD, and outputs the obtained channel estimation value to the coherent detection section 109.

Data despreading section 108 performs despreading processing on the data using the spreading code used on the communication terminal side, and outputs the signal after the despreading processing (despreading signal) to synchronous detection section 109. To do.

The coherent detection section 109 performs coherent detection on the despread signal of the data using the channel estimation value,
The signal after the synchronous detection is output to RAKE combining section 110.
The RAKE combining unit 110 performs RAKE combining using the signal after the synchronous detection, and the decoding unit 1 performs the RAKE combining signal.
Output to 11. Decoding section 111 decodes the signal after RAKE combining to obtain received data.

Next, the Doppler frequency detecting method of the present invention will be described with reference to FIG. FIG. 2 is a block diagram showing an internal configuration of fD detection section 106 of the wireless reception apparatus according to Embodiment 1 of the present invention.

The fD detection unit 106 uses the in-phase addition result to perform the delay detection at a predetermined interval.
061, an in-phase addition unit 1062 that performs in-phase addition on signals after delay detection for each reception timing (multipath), a frequency offset correction unit 1063 that performs frequency offset correction using the in-phase addition result, and a signal after frequency offset correction I component determination unit 1 for determining an I (in-phase) component using
064 and.

A case will be described in which the fD detection section 106 having the above-mentioned configuration performs fD detection. First, the delay detection unit 1061
In, the differential detection is performed using the result of the in-phase addition performed by the in-phase addition unit 105. This differential detection result is shown in FIG.
As shown in (c). In FIG. 4, the horizontal axis is the I axis and the vertical axis is the Q axis. FIG. 4 (a) shows a case where the Doppler frequency is medium speed, for example, a case where the user is moving by bicycle, etc., and FIG. 4 (c) shows a case where the Doppler frequency is high, for example, a train or a car drives at high speed. It shows the case of moving.

As can be seen from FIGS. 4 (a) and 4 (c), the faster the movement, the greater the amount of phase rotation. Since the phase rotation occurs in the opposite directions as described above, the differential detection result appears symmetrically with respect to the I axis.

The differential detection results are output to the in-phase addition section 1062. In-phase addition section 1062 adds in-phase the results of differential detection. In this way, when the differential detection results are added in-phase, if there is no frequency offset,
Since the results of differential detection appear symmetrically with respect to the I axis,
As shown in (b) and (d), it appears almost on the I axis. Note that FIG. 4B shows a case where the Doppler frequency is medium speed, for example, a case where the user is moving by bicycle, etc., and FIG. 4D shows a case where the Doppler frequency is high, for example, by train or car. It shows the case of moving at high speed.

The in-phase addition result is output to the frequency offset correction unit 1063, and the frequency offset correction is performed there. In the frequency offset correction, the frequency offset detection unit 112 detects the frequency offset by performing in-phase addition on the differential detection results, and multiplies the in-phase addition result obtained by the in-phase addition unit 1062 by the complex conjugate of this frequency offset. To do. The frequency offset correction result is output to the I component determination unit 1064.

The I component determination unit 1064 determines fD using the in-phase addition result corrected for frequency offset. For example, fD is determined by the amplitude of the I component, or I
The sign of the component is used to determine fD, or the amplitude and sign of the I component is used to determine fD. For example, the I component determination unit 1064 sets a predetermined threshold value, determines whether the amplitude of the I component is greater than or equal to this threshold value or less than the threshold value, and determines fD.

As can be seen from FIGS. 4 (a) and 4 (c), as the Doppler frequency increases, the position where the differential detection result is distributed departs from the I axis. That is, the amplitude of the I component decreases as the Doppler frequency increases. Therefore, if the amplitude of the I component is small, it is determined that fD is relatively high speed, and if the amplitude of the I component is large, fD is determined.
It can be determined that D is relatively medium speed or low speed.

As can be seen from FIGS. 4 (a) and 4 (c), when the Doppler frequency becomes higher, the position where the differential detection result is distributed is on the left side of the Q axis. That is,
The sign of the I component changes from positive to negative as the Doppler frequency increases. Therefore, FIGS. 4 (b) and 4 (d)
As shown in, if the sign of the I component is negative, it is determined that fD is relatively fast, and if the sign of the I component is positive, fD is
It can be determined that D is relatively medium speed or low speed.

As described above, according to the Doppler frequency detecting method of the present invention, the result after the in-phase addition of the differential detection results is subjected to the fD detection by the amplitude of the I component and the sign of the I component, which is the conventional method. , Because it is not necessary to find the angle,
The amount of calculation can be reduced.

Further, in the method of the present invention, since the differential detection result is not folded back around the I-axis, the center phase of the spread of the differential detection result does not change due to the received SIR, so that a judgment table according to the received SIR, etc. Since it is not necessary to have the above, it is possible to reduce the calculation amount and the circuit scale as compared with the conventional method.
For this reason, it is not necessary to measure the SIR for detecting the Doppler frequency, and even if the SIR for power control does not need to be measured (eg PRACH), the S
Doppler frequency detection can be performed without adding an IR measurement function.

As described above, the differential detection result I
It is considered that the effect of the in-phase addition is large and the noise is canceled even if it is affected by the noise by performing the in-phase addition without returning to the axis. Therefore, it is not necessary to make the averaging length sufficiently long.
It becomes possible to detect the Doppler frequency using a signal transmitted in bursts such as H.

Further, according to the conventional method, it is necessary to correct the frequency offset every time the differential detection is performed.
In the method of the present invention, since the frequency offset correction may be performed after the in-phase addition of the differential detection results, the amount of calculation can be reduced as compared with the conventional method.

Next, the case where the fD detected by the above Doppler frequency detecting method is used for channel estimation will be described.

The fD detected by the above method is output to the channel estimation section 107. Channel estimation unit 107
As shown in FIG. 3, a first in-phase addition result storage unit 1071 and a second in-phase addition result storage unit 1072 that store in-phase addition results when the number of in-phase additions is changed, and a first in-phase addition result storage unit 1071 and second in-phase addition result storage unit 1072
A switching unit 1073 that switches and outputs the in-phase addition result according to fD and a channel estimation value calculation unit 1074 that obtains a channel estimation value using the in-phase addition result.

In this case, first, in-phase addition section 105 determines a plurality of types of in-phase addition numbers in advance, and obtains the in-phase addition result of each in-phase addition number. For example, 3
The number of slots and the number of slots are determined in advance. And 3
The in-phase addition result for the slots is stored in the first in-phase addition result storage unit 1071, and the in-phase addition result for 10 slots is stored in the second in-phase addition result storage unit 1072. The number of in-phase additions determined in advance is not limited to two, and may be three or more.

The number of in-phase additions of PL signals needs to be small when fD is relatively high speed, and needs to be large when fD is relatively low speed. Therefore,
The switching unit 1073 switches which in-phase addition result is to be output based on the fD detected by the fD detection unit 106.

That is, when fD is relatively high speed, the first in-phase addition result storage unit 1071 outputs the in-phase addition results for three slots, and when fD is medium speed or low speed, the second in-phase addition result is output. The channel estimation value calculation unit 1074 stores the in-phase addition results for 10 slots from the in-phase addition result storage unit 1072.
Output to. The channel estimation value calculation unit 1074 obtains a channel estimation value using the in-phase addition result. The channel estimation value is output to the coherent detection unit 109.

With such a configuration, it is possible to perform the coherent detection using the channel estimation value corresponding to fD, and therefore it is possible to perform appropriate channel estimation according to fD, that is, according to the moving speed. It is possible to perform accurate synchronous detection.

In this embodiment, the case where two in-phase addition numbers are determined in advance, both in-phase addition results are obtained, and one of them is selected and used for channel estimation will be described. However, in the present invention, channel estimation is performed with a certain number of in-phase additions, and the number of in-phase additions is changed according to fD, for example, information of fD from the fD detection unit 106 is added to the in-phase addition unit. Output to 105,
The in-phase addition unit 105 may be configured to change the in-phase addition number according to fD. As a result, it is not necessary to obtain two in-phase addition results, the amount of calculation can be reduced, and the amount of information to be stored can be reduced.
Similarly, when the in-phase addition number is controlled by the weighting coefficient, f
The weighting coefficient may be changed according to D.

(Embodiment 2) In this embodiment, a case will be described in which the detected fD is changed by changing the interval of differential detection.

FIG. 5 is a block diagram showing the internal configuration of fD detection section 106 of the radio reception apparatus according to Embodiment 2 of the present invention. 5, the same parts as those in FIG. 2 are designated by the same reference numerals as those in FIG. 2 and their detailed description is omitted. Figure 5
In the fD detection section 106 shown in FIG.
Interval information indicating the delay detection interval is input to 1.

When the fD is from high speed to medium speed, the fading fluctuation is large, so that it is possible to detect the fD more accurately if the delay detection interval is relatively narrowed (not separated).
Since the fading fluctuation is small when fD is from medium speed to low speed, it is possible to detect fD with high accuracy by relatively widening (separating) the delay detection interval.

Therefore, in the case of high speed movement, the delay detection unit 1061 outputs the interval information for narrowing the delay detection interval.
Then, the differential detection unit 1061 performs differential detection based on the interval information and performs fD determination. Also,
In the case of low speed movement, interval information for widening the differential detection interval is output to the differential detection unit 1061 and the differential detection unit 1061 performs differential detection based on the interval information to perform fD determination. It should be noted that whether or not the vehicle is moving at high speed can be determined by feeding back the fD detection result.

As described above, by changing the delay detection interval, the desired fD can be determined in the vicinity of 90 °, so that the fD can be detected more accurately.

Further, by changing the delay detection interval in a plurality of stages, it is possible to detect a plurality of fDs more accurately. For example, first, the differential detection interval is narrowed, and it is determined whether fD is high speed or medium speed. That is, using FIG. 4, it is determined whether the high speed (negative) or the medium speed (positive) based on the sign of the I component. If it is determined to be medium speed,
Next, the differential detection interval is widened to determine whether fD is medium speed or low speed. That is, similarly, using FIG. 4, it is determined whether the medium speed (negative) or the low speed (positive) is based on the sign of the I component.

The present invention is not limited to the first and second embodiments described above, but can be implemented with various modifications. For example, in the first and second embodiments, the case where the detected fD is used for channel estimation has been described, but the present invention is not limited to this, and the detected fD is used as the average length of path search, adaptive modulation selection, It may be applied to speed detection, position detection and the like.

Further, the radio receiving apparatus of the present invention can be applied to a digital radio communication system, in particular, a CDMA radio base station apparatus or a communication terminal apparatus. As a result, accurate fD detection can be performed, and the accuracy of processing that is affected by fD can be improved.

[0062]

As described above, according to the present invention, the fD detection is performed by the amplitude of the I component and the sign of the I component with respect to the result after the in-phase addition of the differential detection results. Since it is not necessary to calculate, the calculation amount can be reduced. In addition, since the differential detection result is not folded back around the I axis, the center phase of the spread of the differential detection result does not change due to the received SIR, so there is no need to have a determination table or the like according to the received SIR, Amount of computation,
The circuit scale can be reduced. For this reason, it is not necessary to measure the SIR for detecting the Doppler frequency, and it is possible to perform the Doppler frequency detection without adding the SIR measurement function even in a channel (for example, PRACH) that does not need to measure the SIR for power control. It will be possible. Further, by adding the in-phase results of the differential detection results to the I-axis without folding them back, it is considered that the effects of the in-phase addition are large and the noises are canceled even if they are affected by the noise. For this reason, there is no need to make the averaging length sufficiently long, and it becomes possible to detect the Doppler frequency using a signal transmitted in bursts such as PRACH. Further, since the frequency offset correction may be performed after the in-phase addition of the differential detection results, the amount of calculation can be reduced as compared with the conventional case.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a wireless reception device according to a first embodiment of the present invention.

[FIG. 2] f of the wireless reception device according to the first embodiment of the present invention
Block diagram showing the internal configuration of the D detector

FIG. 3 is a block diagram showing an internal configuration of a channel estimation unit of the wireless reception device according to the first embodiment of the present invention.

FIG. 4 is a diagram for explaining the Doppler frequency detection method of the present invention.

[Fig. 5] Fig. 5f of the wireless reception device according to the second embodiment of the present invention
Block diagram showing the internal configuration of the D detector

FIG. 6 is a diagram for explaining a conventional Doppler frequency detection method.

[Explanation of symbols]

101 antenna 102 wireless receiver 103 PL despreader 104 Quadrant correction unit 105 In-phase adder 106 fD detector 107 channel estimation unit 108 data despreading unit 109 Synchronous detection section 110 RAKE synthesizer 111 Decryption unit 1061 Delay detection unit 1062 In-phase addition unit 1063 frequency offset correction unit 1064 I component determination unit 1071 First in-phase addition result storage unit 1072 Second in-phase addition result storage unit 1073 switching unit 1074 channel estimation value calculator

Claims (8)

[Claims] 1. A differential detection means for performing differential detection on a known signal included in a received signal, an in-phase addition means for adding in-phase results of the delayed detection, and an in-phase addition result in a signal space diagram. In-phase-determining means for performing Doppler frequency determination by the in-phase component on the quadrature axis,
A wireless reception device comprising: 2. The radio receiving apparatus according to claim 1, wherein the determining means determines the Doppler frequency based on the sign of the in-phase component on the in-phase-quadrature axis in the signal space diagram. 3. The radio reception apparatus according to claim 1, wherein the Doppler frequency determination is performed in a plurality of stages by changing the delay detection interval. 4. The radio receiving apparatus according to claim 1, further comprising channel estimation means for performing channel estimation based on a Doppler frequency determination result. 5. The radio receiving apparatus according to claim 1, wherein the received signal is a signal transmitted in burst. 6. A radio base station apparatus comprising the radio receiving apparatus according to claim 1. Description: 7. A wireless mobile station device comprising the wireless receiving device according to claim 1. Description: 8. A differential detection step of performing differential detection on a known signal included in a received signal, an in-phase addition step of adding in-phase results of the delayed detection, and a result of the in-phase addition result in a signal space diagram. In-phase-a determination step of performing Doppler frequency determination by the in-phase component on the quadrature axis,
A Doppler frequency detecting method comprising: