JP2006074605A - Apparatus and method for antenna verification - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the accuracy of antenna verification. <P>SOLUTION: A feedback information creation part 530 creates feedback information to a base station device using a channel estimation value of a common pilot channel, stores it in a storage part 540, a phase correction amount calculation part 550 acquires the feedback information stored in the storage part 540, performs antenna verification processing using a channel estimation value of a data channel and the channel estimation value of the common pilot channel and calculates a phase correction amount. In this case, the phase correction amount calculation part 550 calculates the phase correction amount based on magnitude relation between error rate of the feedback information calculated by an error rate calculation part 600 and an integration value of parameters equivalent to complex weighting factors for each slot. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an antenna verification apparatus and an antenna verification method, and more particularly to an antenna verification apparatus and an antenna verification method used in a mobile communication system to which closed-loop transmission diversity is applied.

  In a mobile communication environment, reception characteristics are significantly degraded due to the influence of amplitude and phase fluctuations due to multipath fading. Therefore, a transmission diversity technique that obtains a diversity effect by transmitting signals using a plurality of antennas in a base station is effective. As a result, diversity gain can be obtained without increasing the number of antennas of mobile stations that are strongly demanded for miniaturization.

Currently, the W-CDMA system standardized in the ^{3GPP (3 rd Generation Partnership Project)} , as a transmission diversity system, the open-loop mode that does not require feedback information from the mobile station, based on the feedback information from the mobile station Both closed-loop modes that control the phase and amplitude of signals transmitted from the base station antenna are employed. There are STTD (Space Time block coding based Transmit Diversity) and TSTD (Time Switched Transmit Diversity) in the open loop mode. There is mode 2 (hereinafter abbreviated as “CL2”) that controls both amplitudes.

  In CL1 and CL2, the mobile station transmits uplink feedback information so that the combined vector of signals transmitted from the two base station antennas (antenna 1 and antenna 2) is maximized at the mobile station receiving antenna end, and the base station Controls the phase of a desired channel on the antenna 2 side (for example, DPCH (Dedicated Pilot Channel) or HSPDSCH (High Speed Physical Downlink Shared Channel)) according to the feedback information. Accordingly, the phase of the CPICH (Common Pilot Channel) used for phase estimation and the phase of the desired channel are different, and CPICH cannot be used for phase estimation as it is. Therefore, the mobile station performs antenna verification, estimates the phase control value on the base station antenna 2 side, adds the estimated phase control value to the phase estimation value calculated from CPICH, and uses it for synchronous detection of the desired channel. (For example, refer to Patent Document 1).

Further, when CL1 is applied, the base station apparatus controls the phase of the desired channel on the antenna 2 side based on feedback information from the mobile station. Four types of complex weight coefficients (I, Q) = (1 / 2,1 / 2), (1/2, -1 / 2), (-1 / 2, -1 / 2), (-1 / 2,1 / 2) is used. However, since only 1 bit is allocated to the feedback information from the mobile station to the base station, the I-axis information and the Q-axis information are alternately transmitted as feedback information for each slot. For the paths i = 1 to N, a parameter Vi for antenna verification corresponding to the complex weight coefficient for each slot of the i-th path can be obtained by the following equation (1).

If the slot number is an even number, T = ln (96/4) = 3.178 if the feedback information is “1”, and T = ln (4/96) = − if the feedback information is “0”. 3.178. When the slot number is an even number, the feedback information “1” corresponds to the phase correction amount: π, and the feedback information “0” corresponds to the phase correction amount: 0. Further, (96/4) and (4/96) indicate the ratios when the probability that the feedback information is correctly transmitted is 96% and the transmission error rate is 4%. If the condition of the following equation (2) is satisfied, x0 = 0, and if not, x0 = π.

When the slot number is an odd number, T = ln (96/4) = 3.178 if the feedback information is “1”, and T = ln (4/96) = − if the feedback information is “0”. 3.178. When the slot number is an odd number, feedback information “1” corresponds to a phase correction amount: −π / 2, and feedback information “0” corresponds to a phase correction amount: π / 2. If the condition of the following expression (3) is satisfied, x1 = −π / 2, and if not, x1 = π / 2.

From the above x0 and x1, the phase correction amount in the antenna 2 of the base station can be estimated as shown in the following equation (4).

The antenna verification process is performed using the above-described expressions (1) to (4), and therefore, a transmission error rate of feedback information is required for this process. In Non-Patent Document 1, it is assumed that the transmission error rate of uplink feedback information is 4% (fixed value) as a general operation.
JP 2003-8552 A 3GPP TS 25.214 V5.5.0 (3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Physical layer procedures (FDD) (Release 5)) Annex A

  However, since the transmission error rate of the uplink feedback information depends on the propagation path state, the antenna verification accuracy deteriorates when a fixed value is used.

  The present invention has been made in view of this point, and an object thereof is to provide an antenna verification apparatus and an antenna verification method that can improve the accuracy of antenna verification.

  The antenna verification apparatus according to the present invention is configured to generate feedback information from a channel estimation value of a common pilot channel to a base station apparatus, the feedback information from the feedback information and a phase correction amount corresponding to the feedback information. Data in the base station apparatus on the basis of the magnitude relationship between the error rate calculation means for calculating the error rate and the integrated value of the parameter corresponding to the complex weight coefficient for each slot and the value calculated using the error rate And a correction amount calculating means for calculating a correction amount of the phase rotation applied to the channel.

  According to the present invention, since the error rate of the feedback information according to the propagation path state is used for the antenna verification processing, it is possible to improve the antenna verification accuracy.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The antenna verification device described below is used by being mounted on a wireless communication mobile station device of a W-CDMA system to which, for example, closed-loop (mode 1) transmission diversity is applied.

(Embodiment 1)
FIG. 1 is a block diagram showing a configuration of an antenna verification apparatus according to Embodiment 1 of the present invention.

  The antenna verification apparatus shown in this figure includes an antenna 10, a duplexer 100, a receiving unit 200, a data channel despreading unit 410, a synchronous detection unit 420, a channel estimation unit 430, a common pilot channel despreading unit 510, and a channel estimation unit. 520, a feedback information creation unit 530, a storage unit 540, a phase correction amount calculation unit 550, an error rate calculation unit 600, and a transmission unit 300.

  A data channel signal transmitted from a base station apparatus including two antennas 1 and 2 is received by the antenna 10, and then sequentially passes through the duplexer 100 and the receiving unit 200 to the data channel despreading unit 410. Entered. The receiving unit 200 performs processing such as down-conversion and A / D conversion.

  The data channel despreading unit 410 performs despreading on the data channel signal with a predetermined spreading code. The despread data channel signal is input to synchronous detection section 420 and channel estimation section 430.

  Channel estimation section 430 obtains a channel estimation value of the data channel signal transmitted from antenna 2 of the base station apparatus using pilot symbols inserted into the despread data channel signal. This channel estimation value is input to the phase correction amount calculation unit 550.

  On the other hand, the common pilot channel signal transmitted from the base station apparatus is received by the antenna 10 and then input to the common pilot channel despreading unit 510 sequentially through the duplexer 100 and the receiving unit 200.

  Common pilot channel despreading section 510 despreads the common pilot channel signal with a predetermined spreading code. The despread common pilot channel signal is input to channel estimation section 520.

  Channel estimation section 520 obtains a channel estimation value of the common pilot channel signal transmitted from antenna 1 and antenna 2 of the base station apparatus using the despread common pilot channel signal. This channel estimation value is input to the phase correction amount calculation unit 550 and the feedback information creation unit 530.

  Feedback information creation section 530 creates feedback information to the base station apparatus using the channel estimation value obtained by channel estimation section 520. For example, the feedback information creation unit 530 obtains a phase difference between the channel estimation value of the common pilot channel signal transmitted from the antenna 1 and the channel estimation value of the common pilot channel signal transmitted from the antenna 2, and transmits the phase difference. Create feedback information by converting to bits. The created feedback information is input to the transmission unit 300 for notification to the base station apparatus, and is also input to the storage unit 540 for storage.

  The phase correction amount calculation unit 550 acquires the feedback information stored in the storage unit 540, and receives the channel estimation value (the channel estimation value of the data channel of the antenna 2) input from the channel estimation unit 430 and the channel estimation unit 520. An antenna verification process is performed using the input channel estimation value (channel estimation value of the common pilot channel of antenna 1 and antenna 2), and a phase correction amount is calculated. This phase correction amount corresponds to the phase rotation correction amount added to the data channel signal in the base station. For the calculation of the phase correction amount, the method represented by the above formulas (1) to (4) is used. However, the transmission error rate of feedback information necessary for calculating the parameter T used in the above equations (2) and (3) is the transmission error rate calculated by the error rate calculation unit 600 described later. Then, the phase correction amount calculation unit 550 corrects the phase of the channel estimation value input from the channel estimation unit 520 using the calculated phase correction amount. The phase-corrected channel estimation value is input to the synchronous detector 420. The phase correction amount calculated by the phase correction amount calculation unit 550 is input to the storage unit 540 and stored.

  The synchronous detection unit 420 performs synchronous detection processing on the despread data channel signal according to the phase-corrected channel estimation value, and outputs received data.

  The error rate calculation unit 600 calculates a transmission error rate using the feedback information and the phase correction amount stored in the storage unit 540. The internal configuration of the error rate calculation unit 600 is shown in FIG. As shown in FIG. 2, the error rate calculation unit 600 includes a first quadrant determination unit 610, a second quadrant determination unit 620, a comparison unit 630, and a calculation unit 640.

  First quadrant determination unit 610 performs quadrant determination using feedback information, and outputs the determination result to comparison unit 630. The quadrant determination by the first quadrant determination unit 610 is performed as follows.

  As described above, since only one bit is assigned as feedback information in CL1, I-axis information and Q-axis information are alternately transmitted for each slot. In the mobile station, the phase amount to be corrected by the base station is calculated from the feedback information transmitted by the mobile station. There are two types of phase correction amounts to be calculated for even slots and odd slots, respectively. In the even slot, as shown in FIG. 3, when the feedback information is ‘0’, the phase is corrected to 0 side, and when the feedback information is ‘1’, the phase is corrected to π side. Therefore, in the even slot, the quadrant is determined as 0 if the feedback information is ‘0’, and π if the feedback information is ‘1’. In the odd slot, as shown in FIG. 4, the phase is corrected to the π / 2 side when the feedback information is “0”, and the phase is corrected to the −π / 2 side when the feedback information is “1”. Is done. Therefore, in the odd slot, if the feedback information is ‘0’, the quadrant determination is π / 2, and if the feedback information is ‘1’, the quadrant determination is −π / 2. The first quadrant determination unit 610 inputs this determination result to the comparison unit 630.

  Second quadrant determination unit 620 performs quadrant determination using the phase correction amount obtained by the antenna verification processing in phase correction amount calculation unit 550, and outputs the determination result to comparison unit 630. The quadrant determination by the second quadrant determination unit 620 is performed as follows.

  The phase correction amount obtained by the antenna verification processing can be taken in four ways: ± π / 4 and ± (3π) / 4. In addition, quadrant determination is performed in each of an even slot and an odd slot. There are four possible phase correction amounts, but two types of phase correction amounts are estimated for each slot. In other words, the even slot is estimated as 0 or π, and the odd slot is estimated as π / 2 or −π / 2. Therefore, in the even slot, the quadrant is determined as 0 if the phase correction amount is ± π / 4, and as π if the phase correction amount is ± (3π) / 4. In the odd slot, if the phase correction amount is π / 4 or (3π) / 4, the quadrant is determined as π / 2, and if it is −π / 4 or − (3π) / 4, the quadrant is determined as −π / 2. The second quadrant determination unit 620 inputs this determination result to the comparison unit 630.

  The comparison unit 630 compares the determination result input from the first quadrant determination unit 610 with the determination result input from the second quadrant determination unit 620, and inputs the comparison result to the calculation unit 640. The comparison in the comparison unit 630 is performed based on whether the determination result in the corresponding slot is the same as the determination result input from the first quadrant determination unit 610 and the determination result input from the second quadrant determination unit 620. . For example, the comparison unit 630 determines if the determination result input from the first quadrant determination unit 610 is “0” and the result input from the second quadrant determination unit 620 is “0” in the even slot. The calculation unit 640 is informed that the results are the same. Further, for example, in the even slot, the comparison unit 630 determines that the determination result input from the first quadrant determination unit 610 is “0” and the result input from the second quadrant determination unit 620 is “π”. The calculation unit 640 is notified that the determination results are different (that is, an error). Similarly, the comparison unit 630 informs the calculation unit 640 whether or not the determination results are the same even in odd-numbered slots.

  The calculation unit 640 calculates a transmission error rate based on the comparison result input from the comparison unit 630. For example, if the number of times that the determination result is the same in 100 slots is 95 times and the number of times that the determination results are different is 5, the transmission error rate is 5/100 = 5%. The transmission error rate calculated here corresponds to the error rate of feedback information. The calculated transmission error rate is input to the phase correction amount calculation unit 550.

  The phase correction amount calculation unit 550 uses the transmission error rate input from the error rate calculation unit 600 to perform the processes of the above equations (2) and (3). That is, in the even slot, the phase correction amount calculation unit 550 has T = ln (95/5) = 2.944 if the feedback information is “1”, and T = ln (95) if the feedback information is “0”. 5/95) = − 2.944. Since the transmission error rate input from error rate calculation unit 600 is 5%, the probability that the feedback information is correctly transmitted is 95%. If the condition of the above equation (2) is satisfied, x0 = 0, and if not, x0 = π. Further, in the odd-numbered slot, the phase correction amount calculation unit 550 has T = ln (95/5) = 2.944 if the feedback information is “1”, and T = ln (5) if the feedback information is “0”. /95)=−2.944. If the condition of the above equation (3) is satisfied, x1 = −π / 2, and if not, x1 = π / 2.

  Then, the phase correction amount calculation unit 550 calculates the phase correction amount according to the above equation (4). The calculated phase correction amount is stored in the storage unit 540 and used for phase correction of the channel estimation value of the data channel signal.

  Thus, according to the antenna verification apparatus according to the present embodiment, the transmission error rate according to the propagation path state is adaptively calculated from the feedback information and the phase correction amount, and based on the transmission error rate. Since a new phase correction amount is calculated, it is possible to perform an antenna verification process following a change in the propagation path state, and improve the accuracy of antenna verification.

(Embodiment 2)
An antenna verification apparatus according to Embodiment 2 of the present invention will be described with reference to FIGS. In the following description, the description of the same configuration as in FIGS. 1 and 2 (Embodiment 1) is omitted.

  In FIG. 5, the moving speed measurement unit 560 measures the moving speed of the mobile station on which the antenna verification apparatus according to the present embodiment is mounted using the channel estimation value input from the channel estimation unit 520, The data is input to an error rate calculation unit 600 having the configuration shown in FIG. In addition, about the method of measuring a moving speed from a channel estimated value, since the method generally known is used, description here is abbreviate | omitted.

  In the error rate calculation unit 600 illustrated in FIG. 6, the calculation unit 640 calculates a transmission error rate based on the comparison result input from the comparison unit 630 and the moving speed input from the moving speed calculation unit 560. The calculation unit 640 controls the transmission error rate calculation interval according to the current moving speed of the mobile station. For example, as illustrated in FIG. 7, when the moving speed is 30 km / h or more at the time A, the calculating unit 640 sets the section for calculating the transmission error rate to 200 slots, and the moving speed is also at the time B when 200 slots have elapsed. In the case of 30 km / h or more, the section for calculating the transmission error rate is 200 slots. Further, when the moving speed at time C when 200 slots have elapsed is less than 30 km / h, the calculation unit 640 calculates the transmission error rate with the section for calculating the transmission error rate as 300 slots. The calculated transmission error rate is input to the phase correction amount calculation unit 550. Further, when the moving speed at time D when 300 slots have further passed becomes 30 km / h or more again, the calculation unit 640 sets the section for calculating the transmission error rate as 200 slots. Thus, the calculation unit 640 shortens the transmission error rate calculation section as the moving speed increases. In addition, the calculation unit 640 may multiply the transmission error rate by a weighting factor corresponding to the moving speed and weight the transmission error rate according to the moving speed within the transmission error rate calculation interval.

  Thus, according to the antenna verification apparatus according to the present embodiment, the transmission error rate calculation section is changed in accordance with the moving speed, so that the accuracy of antenna verification can be further improved.

(Embodiment 3)
An antenna verification apparatus according to Embodiment 3 of the present invention will be described with reference to FIG.

  In FIG. 8, a signaling detection unit 440 detects a transmission error rate calculated and notified by a base station from received data. The detected transmission error rate is input to the phase correction amount calculation unit 550. The phase correction amount calculation unit 550 calculates the phase correction amount using this transmission error rate in the same manner as in the first embodiment.

  As described above, according to the antenna verification apparatus according to the present embodiment, since the phase correction amount is calculated using the transmission error rate calculated in the base station, it is necessary to particularly include a configuration for calculating the error rate. Therefore, the accuracy of antenna verification can be improved by minimizing an increase in circuit scale.

  The present invention is suitable for an antenna verification apparatus, a radio mobile station apparatus, and the like used in a mobile communication system such as a W-CDMA system.

1 is a block diagram showing a configuration of an antenna verification apparatus according to Embodiment 1 of the present invention. The block diagram which shows the structure of the error rate calculation part which concerns on Embodiment 1 of this invention. Operation explanatory diagram of the first quadrant determination unit according to Embodiment 1 of the present invention (in the case of an even slot) Operation explanatory diagram of the first quadrant determination unit according to Embodiment 1 of the present invention (in the case of an odd slot) The block diagram which shows the structure of the antenna verification apparatus which concerns on Embodiment 2 of this invention. The block diagram which shows the structure of the error rate calculation part which concerns on Embodiment 2 of this invention. Operation explanatory diagram of the calculation unit according to Embodiment 2 of the present invention The block diagram which shows the structure of the antenna verification apparatus which concerns on Embodiment 3 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Duplexer 200 Reception part 300 Transmission part 410 Data channel despreading part 420 Synchronous detection part 430,520 Channel estimation part 440 Signaling detection part 510 Common pilot despreading part 530 Feedback information creation part 540 Storage part 550 Phase correction amount calculation part 560 Movement speed measurement unit 600 Error rate calculation unit 610 First quadrant determination unit 620 Second quadrant determination unit 630 Comparison unit 640 calculation unit

Claims (6)

Creating means for creating feedback information from the channel estimation value of the common pilot channel to the base station device;
An error rate calculating means for calculating an error rate of the feedback information from the feedback information and a phase correction amount corresponding to the feedback information;
Based on the magnitude relationship between the integrated value of the parameter corresponding to the complex weight coefficient for each slot and the value calculated using the error rate, the correction amount of the phase rotation given to the data channel in the base station apparatus is calculated Correction amount calculating means to perform,
An antenna verification apparatus comprising:   2. The antenna verification apparatus according to claim 1, wherein the error rate calculation means controls a calculation interval of the error rate according to a moving speed.   The antenna verification apparatus according to claim 1, wherein the error rate calculation means weights the error rate according to a moving speed.   2. The antenna verification apparatus according to claim 1, wherein the correction amount calculating means calculates the correction amount using the error rate notified from the base station apparatus.   A radio communication mobile station apparatus comprising the antenna verification apparatus according to claim 1. A creation step of creating feedback information from the channel estimation value of the common pilot channel to the base station device;
An error rate calculating step of calculating an error rate of the feedback information from the feedback information and a phase correction amount corresponding to the feedback information;
Based on the magnitude relationship between the integrated value of the parameter corresponding to the complex weight coefficient for each slot and the value calculated using the error rate, the correction amount of the phase rotation given to the data channel in the base station apparatus is calculated A correction amount calculating step to perform,
An antenna verification method comprising:

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