WO2009139263A1 - Calibration method and communication device - Google Patents
Calibration method and communication device Download PDFInfo
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- WO2009139263A1 WO2009139263A1 PCT/JP2009/057666 JP2009057666W WO2009139263A1 WO 2009139263 A1 WO2009139263 A1 WO 2009139263A1 JP 2009057666 W JP2009057666 W JP 2009057666W WO 2009139263 A1 WO2009139263 A1 WO 2009139263A1
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B17/00—Monitoring; Testing
- H04B17/30—Monitoring; Testing of propagation channels
- H04B17/309—Measuring or estimating channel quality parameters
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B17/00—Monitoring; Testing
- H04B17/20—Monitoring; Testing of receivers
- H04B17/21—Monitoring; Testing of receivers for calibration; for correcting measurements
Definitions
- the present invention relates to a calibration method for performing calibration between a plurality of antennas in wireless communication with high efficiency and a communication apparatus for realizing the calibration method.
- the TDD (Time Division Duplex) method that alternately uses the same frequency in the uplink and the downlink is expected to have an advantage that the channel reversibility can be used in forming the transmission beam.
- channel information is required at the transmitter (transmitter-side radio).
- channel measurement is performed using a pilot signal from the receiver (receiver-side radio device) to the transmitter, thereby easily receiving from the transmitter. The channel status to the machine can be grasped.
- the radio equipment measures the propagation path in the digital domain, but in order to use reversibility, it compensates for the analog characteristic difference between the transmitter and the receiver (transmission / reception system analog characteristic difference). Calibration that maintains the reversibility of the image is usually required.
- a radio having a plurality of antennas transmits / receives test signals to / from other radios, so that a plurality of antennas can be obtained. Compensates for the difference in analog characteristics between the transmitting and receiving systems.
- the self-calibration described in Patent Document 1 and Non-Patent Document 1 has an advantage that a test signal with weak transmission power is exchanged between a plurality of antennas in a wireless device, so that a control signal is unnecessary in a wireless system.
- the test signal transmission power is much lower than the transmission power during communication, the analog characteristics of the amplifier change between the test signal transmission and the communication signal transmission when the transmitter amplifier of the radio is power dependent. There is a case. In this case, even if self-calibration is performed using a test signal, phase matching between antennas cannot be sufficiently maintained during communication.
- the self-calibration has a problem of power dependency of the signal amplifier, while the calibration performed through another radio device has a problem of increasing the amount of control signal.
- the accuracy of the correction coefficient obtained by each of the above methods varies depending on the reception quality (SNR and SINR) of the test signal. It is desirable to exchange test signals in an environment where the influence of noise and interference is small. However, in actuality, there are cases where the transmitted signal is weak in self-calibration, and in the calibration performed via other radios, antennas are used. Due to the wide distance, the correction coefficient is not always obtained with sufficient reception quality, and there is a problem that a test signal that is long in time must be used to ensure calibration accuracy.
- the present invention has been made in view of the above, and realizes a calibration method for efficiently compensating for an analog characteristic difference between antennas by solving the problem of power dependency and control signal amount.
- An object of the present invention is to obtain a communication device that performs the above.
- the present invention is a calibration method in a case where a radio apparatus having a plurality of antennas that perform communication by the TDD method calibrates each antenna, A first calibration step for calculating a first correction coefficient by performing antenna calibration by the radio alone, and a second correction coefficient by performing antenna calibration using communication with other radios A second calibration step to be calculated; and a correction coefficient selection step of selecting one of the first correction coefficient and the second correction coefficient depending on the situation to obtain a final correction coefficient. It is characterized by that.
- FIG. 1 is a diagram illustrating the concept of Method A (self-calibration).
- FIG. 2 is a diagram illustrating the concept of Method B (calibration performed via another wireless device).
- FIG. 3 is a diagram showing the concept of the calibration method of the present embodiment.
- FIG. 4 is a flowchart illustrating an example of a control procedure of the calibration method according to the present embodiment.
- FIG. 5 is a diagram illustrating a signal correction operation during signal transmission.
- FIG. 6 is a diagram illustrating a control signal transmission / reception operation between the wireless device and the base station in the calibration by the method B.
- FIG. 7 is a diagram illustrating a configuration example of a wireless device that realizes the calibration method according to the second embodiment.
- FIG. 8 is a diagram illustrating an operation procedure of the method B used in the calibration method according to the third embodiment.
- FIG. 9 is a diagram illustrating an operation procedure of the method B used in the calibration method according to the third embodiment.
- FIG. 10 is a diagram illustrating an operation procedure of method B used in the calibration method of the third embodiment.
- FIG. 1 is a conceptual diagram of calibration of Method A.
- the wireless device 1 transmits / receives a test signal between two antennas, and calculates an analog characteristic difference between the antennas from the result.
- FIG. 1 shows the case where the number of antennas is 2.
- FIG. 2 is a conceptual diagram of the calibration of the method B.
- the wireless device 1 transmits / receives a test signal between each antenna and another wireless device (for example, the base station 2), and calculates an analog characteristic difference between the antennas from the result.
- component transmission processing unit T BS is attached (transmitter), the components R BS is attached is a reception processing unit (receiver).
- the method A used in the present embodiment may be any conventional self-calibration method.
- the method B used in the present embodiment is the conventional method performed through another wireless device. Any calibration method may be used.
- FIG. 3 is a diagram showing the concept of the calibration method of the present embodiment. As shown in the figure, this embodiment is characterized in that calibration is performed by selectively or adaptively using the method A and the method B depending on the situation.
- FIG. 4 is a flowchart showing an example of the control procedure of the calibration method of the present embodiment.
- the wireless device (communication device) 1 first calculates the correction coefficient u A by the method A (see FIG. 1) and the method B (see FIG. 2), the correction coefficient u B is calculated (step S1).
- the wireless device 1 compares the two calculated correction coefficients u A and u B and confirms whether they are similar (step S2).
- step S2 If the two correction coefficients are similar (step S2, Yes), it is determined that the influence of the power dependency of the transmission amplifier in the method A is small and the method A can be applied, and the correction coefficient u A calculated by the method A is determined. Is adopted (step S3). A method for determining whether the correction coefficients are similar will be described later. Further, in order to compensate for the temperature change, the correction coefficient is calculated by the method A when a certain time has elapsed, and the correction coefficient u A is updated (step S4). Further, it is confirmed whether or not it is necessary to reselect the correction coefficient calculation method (step S5). If reselection is necessary (step S5, Yes), the process proceeds to step S1.
- step S5 if there is no need for reselection (step S5, No), the correction coefficient is calculated by the method A when a fixed time has passed and the correction coefficient u A is updated (step S4). Thereafter, the processes in steps S4 and S5 are repeated until it is determined in step S5 that the correction coefficient calculation method needs to be selected again.
- step S2 when the two correction coefficients are not similar but greatly different (step S2, No), it is determined that the influence of the power dependency of the transmission amplifier in the method A is large and the method A is not applicable. Then, the correction coefficient u B calculated by the method B is employed (step S6). Further, in order to compensate for the temperature change, the correction coefficient is calculated by the method B when a certain time has elapsed, and the correction coefficient u B is updated (step S7). Further, it is confirmed whether or not it is necessary to reselect the correction coefficient calculation method (step S8). If reselection is necessary (step S8, Yes), the process proceeds to step S1.
- step S8 if there is no need for reselection (step S8, No), the correction coefficient is calculated by the method B when a certain time has passed and the correction coefficient u B is updated (step S7). Thereafter, the processes in steps S7 and S8 are repeated until it is determined in step S8 that the correction coefficient calculation method needs to be reselected.
- the correction coefficient is a value that is individually set for each antenna in order to compensate for a transmission / reception system analog characteristic difference.
- the first antenna (antenna # 1) is normally used as a reference, and the correction coefficient is set to 1 for the reference antenna.
- the other antenna (antenna #m) corrects the transmission signal or the reception signal using the correction coefficient so that the same transmission / reception analog characteristics as the reference antenna are obtained.
- the calibration between the two antennas is assumed, and the correction coefficients at the second antenna (antenna #m) are shown as u A and u B. This is just an example, and the same concept can be applied to the case of three or more antennas.
- the method A with a small amount of control signal is used when the problem of the power dependency of the amplifier is small in the method A, and the power dependency when the influence of the power dependency is large.
- Method B that is not affected by the above is used.
- the method A and the method B are properly used depending on the situation.
- the conventional method using only the method A has a problem of power dependency of the amplifier.
- the method A is used only when the power dependency of the amplifier does not matter. There is no power dependency problem.
- the amount of control signal can be suppressed by appropriately using method A in the present embodiment.
- the analog characteristics of the transmission / reception system usually change over time. Therefore, as described above, the calibration is repeatedly executed to follow the characteristic variation. In particular, the analog characteristics are likely to change according to the temperature change, but can usually be regarded as constant for about 1 minute. Accordingly, in steps S4 and S7, the selected method (method A in step S4, method B in step S7) is repeatedly executed, for example, in a time period of about 1 minute, and the correction coefficient is updated.
- the process of steps S1 and S2 that is, the process of selecting the method to be applied is a period (for example, 1 hour period, 1 day period, etc.) sufficiently longer than the period of updating the correction coefficient in steps S4 and S7. Execute.
- steps S5 and S8 it is confirmed whether or not a predetermined period (one hour period, one day period, etc. sufficiently longer than 1 minute) has elapsed after the method selection is performed, and the transition destination is determined according to the confirmation result.
- a predetermined period one hour period, one day period, etc. sufficiently longer than 1 minute
- the process of selecting the method to be applied may be performed when the radio power has moved and the transmission power used for communication has changed greatly, instead of determining the elapsed time since the process was executed.
- determination based on elapsed time and determination based on transmission power may be used in combination.
- the wireless device 1 when the wireless device 1 having a plurality of antennas performs calibration with the base station 2, the wireless device 1 first transmits a request signal for requesting the calibration by the method B to the base station 2, and the base station 2 transmits the wireless device.
- the request signal from 1 is received
- calibration by the method B is executed between the wireless device 1 and the base station 2.
- the wireless device 1 also performs calibration by the method A independently. Thereafter, the wireless device 1 compares the two correction coefficients obtained by the method A and the method B, and selects one of them (corresponding to the processing in steps S1 and S2 in FIG. 4).
- the calibration control that requests the base station 2 to stop the calibration control Send a stop signal.
- the base station 2 receives the calibration control stop signal
- the base station 2 stops the calibration by the method B, and thereafter, the radio device 1 performs the calibration by the method A at regular intervals.
- the radio device 1 controls the base station 2 to perform calibration control.
- a calibration control continuation signal for requesting continuation of is transmitted.
- the base station 2 receives the calibration control continuation signal
- the base station 2 continues the calibration by the method B, so that the test signal is exchanged with the wireless device 1 at a specific cycle, and the calibration by the method B is executed.
- the wireless device 1 notifies the base station 2 of a calibration control stop signal or continuation signal according to the selection of the method A and the method B.
- the control of the base station 2 and the wireless device 1 is shown here as an example, the above-described control may be performed between any two wireless devices.
- step S2 a method for determining whether the correction coefficients u A and u B are similar or greatly different in step S2 described above will be described below.
- Various methods can be used as this determination method. For example, the determination can be made using the following equation (1).
- T is a threshold value.
- u A and u B are complex numbers, but if the ratio is close to 1, the correction coefficients u A and u B can be regarded as similar. Therefore, if the equation (1) is satisfied, it is determined that the correction coefficients are similar, and the control shown in steps S3 to S5 is executed. If the equation (1) is not satisfied, the control shown in steps S6 to S8 is executed.
- a method of determining the similarity between the correction coefficients u A and u B based on various criteria can be considered.
- the calibration method of Method B which requires a control signal for transmitting and receiving test signals to and from other wireless devices and is complicated, is used depending on the situation.
- the self-calibration (method A) that is easy to process is adopted, and when there is power dependency and sufficient correction performance cannot be obtained by method A, the processing is
- the calibration (method B) which is complicated but does not degrade the correction accuracy due to the influence of power dependency, is performed using communication with other wireless devices (method B).
- a calibration method that efficiently compensates for the difference in analog characteristics between antennas can be obtained.
- the antenna calibration assuming two antennas has been described.
- the correction coefficient vector U A [1, u A (2), u A (3), ..., u A (N)] T
- U B [1, u B (2), u B (3), ..., u B (N)] T
- equivalent control is applied.
- the similarity between the vectors U A and U B can be determined by the following equation (2), for example.
- the value of the left side of the above equation (2) increases when the directions of the vectors U A and U B are close. Therefore, when the left side of Equation 2 is larger than a certain threshold value V, the vectors U A and U B can be regarded as similar states.
- the calibration method of the present embodiment can be applied to the case of performing calibration with three or more antennas.
- Embodiment 2 the calibration method according to the second embodiment will be described.
- the calibration method described in the first embodiment has been described assuming that any method may be used without particularly mentioning the method A (self-calibration) to be used.
- An example of Method A will be described. Specifically, a calibration method is described in which the reception quality of the test signal to be used is predicted, and the method A is performed while changing the length of the test signal according to the prediction result.
- FIG. 7 is a diagram illustrating a configuration example of a radio that realizes the calibration method according to the second embodiment.
- reception quality prediction is performed and the length of a test signal used for calibration is controlled.
- wireless machine 1a to perform is shown.
- the wireless device 1a includes a transmission / reception control unit 11 that performs signal transmission / reception processing, a power measurement unit 12 that measures the power of a reception signal, a reception quality prediction unit 13 that predicts reception quality of a test signal, and a test signal to be transmitted.
- a test signal sequence length determination unit 14 that determines the length of the signal, and a parameter control unit 15 that sets various parameters when executing the calibration operation.
- the power measurement unit 12 collects power measurement data necessary for the reception quality prediction unit 13 in the subsequent stage to predict reception quality. For example, the power measurement unit 12 measures noise power (including interference power) in a silent section and calculates the magnitude of noise power.
- the reception quality prediction unit 13 next predicts reception quality such as SNR and SINR using the power measurement data.
- the reception quality prediction operation in addition to the noise power data calculated by the power measurement unit 12, the power level of the signal scheduled to be transmitted, and the literature “Noda, Hara, Yano, Kubo,“ bidirectional channel measurement in the TDD system are used.
- the radio 1a is equipped with an attenuator (attenuator) described in "Antenna array self-calibration used", IEICE Technical Report RCS2008-12, May 2008, the amount of attenuation ( The reception quality is predicted using the attenuation rate.
- the attenuation amount utilized is hold
- the received signal power can be estimated from, for example, a value obtained by subtracting the propagation loss between the plurality of antennas of the radio station 1a and the attenuation amount of the attenuator from the planned transmission power (power of the signal scheduled to be transmitted),
- the SNR can be predicted from this and the noise power measurement result described above.
- This prediction result is sent to the test signal sequence length determination unit 14, and the test signal sequence length determination unit 14 uses it in calibration based on the reception quality prediction result (for example, SNR) received from the reception quality prediction unit 13.
- the reception quality prediction result for example, SNR
- For the number of symbols for example, a comparison table of the SNR and the required number of symbols is created and held in advance, and the number of symbols is determined by comparing this comparison table with the SNR received from the reception quality prediction unit 13.
- the determined number of symbols is held in the parameter control unit 15, and the test signal having the number of held symbols is used during calibration.
- the reception quality is predicted for each combination of the reference antenna and each antenna to be calibrated, and the test signal length (number of symbols) is determined for each combination. If you want to avoid complication of control, predict the reception quality and determine the test signal length for any one combination, and fix the test signal of the determined length in all combinations. It may be used.
- the radio that performs calibration predicts the reception quality of the test signal, and performs the calibration process using the test signal having a length corresponding to the prediction result. .
- the reception SNR of the test signal at the time of calibration is poor, the number of symbols of the test signal is correspondingly increased and the calibration process is performed, so that necessary accuracy can be ensured.
- a sufficient reception SNR can be obtained, it is possible to obtain an effect such as suppressing transmission of an unnecessary number of symbols and shortening a communication disconnection time that occurs when the calibration process is performed.
- the accuracy of the necessary correction coefficient is changed depending on the modulation method used at the time of data communication after calibration. For example, even in a system that uses a modulation scheme that requires a small calibration distance and a higher calibration accuracy, and a system that uses adaptive modulation, the accuracy is controlled by the modulation scheme and the predicted reception quality, It is possible to prevent a decrease in communication efficiency due to calibration accuracy.
- the case where a method of predicting using the power measurement result of the silent section is applied as a method of predicting the reception quality has been described.
- a system that performs calibration periodically In the method of using the received power at the time of the previous calibration, the method of using the received power at the time of the most recent data communication, and receiving the received power and SNR from the wireless station that is the communication partner, and using it Method (for example, if communication is performed between the same model, the transmission power is known, and the propagation path reversibility between antennas is established, the reception power, noise power, SNR, etc.
- the reception quality of the station can be estimated), and the reception quality may be predicted by combining these.
- Embodiment 3 the calibration method according to the third embodiment will be described.
- the test signal is used in the method B (calibration performed through another wireless device). A case where the length of the test signal to be made is variable will be described.
- FIGS. 8 to 10 are diagrams showing an operation procedure of the method B used in the calibration method of the third embodiment.
- a radio method A having a plurality of antennas is shown.
- FIG. 4 shows an operation procedure in the case where the radio apparatus) also executes the method B while regarding the base station as another radio apparatus.
- FIG. 8 shows a procedure when the reception quality prediction of the test signal and the determination of the test signal length are performed on the wireless device side, and FIG. 9 performs the reception quality prediction of the test signal on the wireless device side to determine the test signal length.
- FIG. 10 shows the procedure when the reception quality prediction of the test signal and the determination of the test signal length are performed on the base station side. In FIG. 8 to FIG. 10, the same step number is assigned to the same process.
- the wireless device performs reception power measurement (step S11), then performs reception quality estimation based on this result (step S12), and further, a test signal based on the reception quality estimation result.
- a sequence length is determined (step S13). Note that the processing executed in each of these steps is the same as the processing executed by the power measurement unit 12, the reception quality prediction unit 13, and the test signal sequence length determination unit 14 described in the second embodiment.
- a signal designating the determined sequence length is transmitted to the base station (step S14), and the base station transmits a test signal having a length determined by the wireless device to the wireless device (step S15). Further, the radio transmits a test signal having a length determined in step S13 to the base station (step S16).
- the base station feeds back the measurement result of the test signal transmitted from the radio device to the radio device (step S17), and the radio device returns the measurement result fed back and the test signal transmitted from the base station in step S15.
- the correction coefficient is calculated based on the reception result (step S18).
- the calibration performed with the test signal having a length corresponding to the reception quality is realized in the same manner as the calibration shown in the second embodiment. Even when the SNR at the time of reception is small, the test signal can be transmitted and received with the corresponding sequence length, and calibration can be performed with the required accuracy.
- the radio notifies the base station of the reception quality (reception quality estimation result) obtained by executing step S12 (step S21). Based on the notified reception quality, the base station determines the length of the test signal (test signal sequence length) (step S22). In this step S22, the base station determines the test signal sequence length in the same procedure as the test signal sequence length determination unit 14 shown in Embodiment 2 determines the test signal sequence length. After the base station determines the test signal sequence length, steps S15 to S18 already described are executed.
- the radio device performs a test such as having the base station notify the sequence length of the test signal to be received in advance, or defining the unique sequence included in the signal as the start and end points of the test signal. Operates by detecting the length of the signal.
- the radio side estimates the reception quality from the reception power measurement result and notifies the base station of the obtained reception quality estimation result.
- the result may be transmitted to the base station as it is, and the base station may execute step S22 after estimating the reception quality based on the notified reception power measurement result.
- the base station executes the same process as in step S11 above to measure the received power (step S31), and further executes the same process as in step S12 above to receive the reception quality. Is estimated (step S32). And a base station performs step S22 already demonstrated using the reception quality estimation result obtained by performing step S32. Thereafter, steps S15 to S18 are executed in the same manner as the procedure shown in FIGS.
- the radio instructs the base station to start the calibration process of method B after determining the test signal sequence length.
- the base station may autonomously determine the test signal sequence length and notify the radio device that the calibration process of method B is started, and then execute the above procedure.
- the radio apparatus notifies the base station of the sequence length of the test signal to be received in advance, or the unique sequence included in the signal is the starting point of the test signal. And, it operates by detecting the length of the test signal by a method such as prescribing as termination.
- the base station and the radio antenna are reversible communication paths, and the noise level (noise power) and transmission power on the radio side are known on the base station side by some method, the base station measures the received power. Since the reception quality result of the radio can be predicted from the result, the procedure shown in FIG. 10 can be adopted.
- the calibration method according to the present invention is useful for wireless communication using a plurality of antennas, particularly when the wireless device efficiently compensates for a difference in transmission / reception system analog characteristics between antennas. Is suitable.
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Abstract
A calibration method wherein a wireless device, which has a plurality of antennas and performs TTD communication, calibrates respective antennas. The method comprises a first calibration step of calculating a first correction coefficient by performing antenna calibration by only the single wireless device, a second calibration step of calculating a second correction coefficient by performing antenna calibration using communication with another wireless device, and a correction coefficient selection step of selecting one of the first correction coefficient or the second correction coefficient corresponding to the situation and setting the selected one to be a final correction coefficient.
Description
本発明は、無線通信において複数アンテナ間のキャリブレーションを高効率に行うキャリブレーション方法およびこれを実現する通信装置に関する。
The present invention relates to a calibration method for performing calibration between a plurality of antennas in wireless communication with high efficiency and a communication apparatus for realizing the calibration method.
高速無線通信への需要は高く、高速な無線通信伝送技術が必要とされている。そのため、最近では無線機が複数アンテナを用いて高速信号伝送を行う技術が広く研究されている。今後の移動通信では基地局が複数の端末へ送信ビームを用いて同時に空間多重伝送する環境も想定される。また、端末においても適切な送信ビーム形成を行うと通信に必要な送信電力を低減できる。従って、高精度な送信ビーム形成技術は今後の重要な課題と考えられる。
Demand for high-speed wireless communication is high, and high-speed wireless communication transmission technology is required. Therefore, recently, a technique in which a radio device performs high-speed signal transmission using a plurality of antennas has been widely studied. In future mobile communications, an environment in which a base station simultaneously performs spatial multiplexing transmission using a transmission beam to a plurality of terminals is also assumed. In addition, transmission power necessary for communication can be reduced by performing appropriate transmission beam forming in the terminal. Therefore, high-accuracy transmission beam forming technology is considered as an important issue in the future.
その中で、上りリンクと下りリンクで同一周波数を交互に用いるTDD(Time Division Duplex)方式では送信ビーム形成にあたり、伝搬路可逆性を利用できる利点に期待が寄せられている。通常、送信ビームを適切に制御するためには送信機(送信側の無線機)でチャネル情報が必要となる。この際、TDD方式において理想的な伝搬路可逆性が得られるとすると、受信機(受信側の無線機)から送信機へのパイロット信号を用いてチャネル測定することで、容易に送信機から受信機へのチャネル状態を把握できる。
Among them, the TDD (Time Division Duplex) method that alternately uses the same frequency in the uplink and the downlink is expected to have an advantage that the channel reversibility can be used in forming the transmission beam. Usually, in order to appropriately control the transmission beam, channel information is required at the transmitter (transmitter-side radio). At this time, assuming that the ideal channel reversibility can be obtained in the TDD system, channel measurement is performed using a pilot signal from the receiver (receiver-side radio device) to the transmitter, thereby easily receiving from the transmitter. The channel status to the machine can be grasped.
しかし、現実には送信機のアンテナ端から受信機のアンテナ端までの実伝搬路で可逆性は成り立つものの、送受信機回路内におけるアナログデバイスの特性差により、デジタル領域で測定される伝搬路(以下、測定伝搬路と呼ぶ)では完全な可逆性が成り立たない。そのため、無線機ではデジタル領域で伝搬路測定を行うが、可逆性を用いるためには送信機と受信機との間のアナログ特性差(送受信系アナログ特性差)を補償して、測定伝搬路での可逆性を維持するキャリブレーションが通常必要となる。
However, in reality, although the reversibility is established in the actual propagation path from the antenna end of the transmitter to the antenna end of the receiver, the propagation path measured in the digital domain (hereinafter referred to as the characteristic difference of analog devices in the transceiver circuit) (Referred to as measurement propagation path) does not hold complete reversibility. For this reason, the radio equipment measures the propagation path in the digital domain, but in order to use reversibility, it compensates for the analog characteristic difference between the transmitter and the receiver (transmission / reception system analog characteristic difference). Calibration that maintains the reversibility of the image is usually required.
このようなキャリブレーションを行う従来技術としては大きく2つに分けることができる。一つは、下記特許文献1や非特許文献1で開示されている自己キャリブレーションである。この自己キャリブレーションでは、無線機内の複数アンテナ間で試験信号を送受信することにより、複数アンテナ間の送受信系アナログ特性差を補償する。
The conventional techniques for performing such calibration can be roughly divided into two. One is self-calibration disclosed in Patent Document 1 and Non-Patent Document 1 below. In this self-calibration, a transmission / reception system analog characteristic difference between a plurality of antennas is compensated by transmitting / receiving a test signal between the plurality of antennas in the wireless device.
もう一つは、下記特許文献2で開示されているキャリブレーションであり、この手法では、複数のアンテナを備えた無線機が他の無線機との間で試験信号を送受信することにより、複数アンテナ間の送受信系アナログ特性差を補償する。
The other is calibration disclosed in Patent Document 2 below. In this method, a radio having a plurality of antennas transmits / receives test signals to / from other radios, so that a plurality of antennas can be obtained. Compensates for the difference in analog characteristics between the transmitting and receiving systems.
特許文献1や非特許文献1に記載された自己キャリブレーションでは無線機内の複数アンテナ間で微弱な送信電力の試験信号をやり取りするため、無線システムにおいて制御信号が不要となる利点がある。しかし、試験信号の送信電力が通信時の送信電力よりも非常に低いため、無線機の送信増幅器に電力依存性のある場合には試験信号送信時と通信信号送信時で増幅器のアナログ特性が変化する場合がある。この場合、試験信号により自己キャリブレーションを行っても通信時にアンテナ間の位相の整合性が十分に保たれない。
The self-calibration described in Patent Document 1 and Non-Patent Document 1 has an advantage that a test signal with weak transmission power is exchanged between a plurality of antennas in a wireless device, so that a control signal is unnecessary in a wireless system. However, because the test signal transmission power is much lower than the transmission power during communication, the analog characteristics of the amplifier change between the test signal transmission and the communication signal transmission when the transmitter amplifier of the radio is power dependent. There is a case. In this case, even if self-calibration is performed using a test signal, phase matching between antennas cannot be sufficiently maintained during communication.
一方、特許文献2に記載された他の無線機を介してキャリブレーションを行う方法では、試験信号の送信電力は通信時の送信電力と類似しているため、送信増幅器に電力依存性があっても通信時にアンテナ間の位相の整合性を保つことができる。しかし、キャリブレーションを行うにあたって、他の無線機との間で試験信号を送受信するためには他の無線機を制御するための制御信号送信が必要となる。
On the other hand, in the method of performing calibration via another wireless device described in Patent Document 2, since the transmission power of the test signal is similar to the transmission power during communication, the transmission amplifier has power dependency. In addition, phase consistency between antennas can be maintained during communication. However, when performing calibration, in order to transmit / receive a test signal to / from another wireless device, it is necessary to transmit a control signal for controlling the other wireless device.
このように、自己キャリブレーションでは信増幅器の電力依存性の問題があり、一方で、他の無線機を介して行うキャリブレーションでは制御信号量が増加する問題があった。
As described above, the self-calibration has a problem of power dependency of the signal amplifier, while the calibration performed through another radio device has a problem of increasing the amount of control signal.
また、上記それぞれの方法で求める補正係数の精度は、試験信号の受信品質(SNRやSINR)によっても変化する。雑音や干渉の影響が小さい環境で試験信号をやりとりすることが望ましいが、実際は自己キャリブレーションにおいては送信信号が微弱である場合があること、また、他の無線機を介して行うキャリブレーションではアンテナ間距離が広いことなどから、十分な受信品質で補正係数が求まるとは限らず、キャリブレーションの精度を確保するために時間的に長い試験信号を使用しなければならないという問題があった。
Also, the accuracy of the correction coefficient obtained by each of the above methods varies depending on the reception quality (SNR and SINR) of the test signal. It is desirable to exchange test signals in an environment where the influence of noise and interference is small. However, in actuality, there are cases where the transmitted signal is weak in self-calibration, and in the calibration performed via other radios, antennas are used. Due to the wide distance, the correction coefficient is not always obtained with sufficient reception quality, and there is a problem that a test signal that is long in time must be used to ensure calibration accuracy.
本発明は、上記に鑑みてなされたものであって、上記電力依存性の問題や制御信号量の問題を解消してアンテナ間のアナログ特性差を効率的に補償するキャリブレーション方法およびこれを実現する通信装置を得ることを目的とする。
The present invention has been made in view of the above, and realizes a calibration method for efficiently compensating for an analog characteristic difference between antennas by solving the problem of power dependency and control signal amount. An object of the present invention is to obtain a communication device that performs the above.
上述した課題を解決し、目的を達成するために、本発明は、TDD方式で通信を行う複数のアンテナを備えた無線機が、各アンテナのキャリブレーションを行う場合のキャリブレーション方法であって、無線機単独でアンテナキャリブレーションを行うことにより第1の補正係数を算出する第1のキャリブレーションステップと、他の無線機との通信を利用したアンテナキャリブレーションを行うことにより第2の補正係数を算出する第2のキャリブレーションステップと、前記第1の補正係数と前記第2の補正係数のいずれか一方を状況に応じて選択し、最終的な補正係数とする補正係数選択ステップと、を含むことを特徴とする。
In order to solve the above-described problems and achieve the object, the present invention is a calibration method in a case where a radio apparatus having a plurality of antennas that perform communication by the TDD method calibrates each antenna, A first calibration step for calculating a first correction coefficient by performing antenna calibration by the radio alone, and a second correction coefficient by performing antenna calibration using communication with other radios A second calibration step to be calculated; and a correction coefficient selection step of selecting one of the first correction coefficient and the second correction coefficient depending on the situation to obtain a final correction coefficient. It is characterized by that.
この発明によれば、アンテナ間のアナログ特性差を効率的に補償するキャリブレーション方法を得ることができる、という効果を奏する。
According to the present invention, it is possible to obtain a calibration method that efficiently compensates for an analog characteristic difference between antennas.
1 無線機
2 基地局(他の無線機)
11 送受信制御部
12 電力測定部
13 受信品質予測部
14 試験信号系列長決定部
15 パラメータ制御部 1Radio 2 Base station (other radio)
DESCRIPTION OFSYMBOLS 11 Transmission / reception control part 12 Electric power measurement part 13 Reception quality prediction part 14 Test signal sequence length determination part 15 Parameter control part
2 基地局(他の無線機)
11 送受信制御部
12 電力測定部
13 受信品質予測部
14 試験信号系列長決定部
15 パラメータ制御部 1
DESCRIPTION OF
以下に、本発明にかかるキャリブレーション方法の実施の形態を図面に基づいて詳細に説明する。なお、この実施の形態によりこの発明が限定されるものではない。また、以下の説明では、簡単化のため、自己キャリブレーションを方法Aと呼び、他の無線機を介して行うキャリブレーションを方法Bと呼ぶこととする。
Hereinafter, embodiments of a calibration method according to the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. In the following description, for the sake of simplicity, self-calibration will be referred to as method A, and calibration performed via another wireless device will be referred to as method B.
実施の形態1.
ここでまず、本実施の形態のキャリブレーション方法で使用する前提技術についての説明を行う。本実施の形態のキャリブレーション方法では、方法Aおよび方法Bのキャリブレーションを使用する。図1は、方法Aのキャリブレーションの概念図である。この方法Aでは、無線機1は2つのアンテナ間で試験信号の送受信を行い、その結果からアンテナ間のアナログ特性差を算出する。無線機1において、Tiが付された構成要素はi番目(i=1,…,m)のアンテナに対応する送信処理部(送信機)であり、Riが付された構成要素はi番目のアンテナに対応する受信処理部(受信機)である。なお、図1は、アンテナ数が2の場合を示しているが、アンテナ数が3の場合には、いずれか1つのアンテナを基準アンテナとして、基準アンテナと他のアンテナとの間で試験信号の送受信を行い、得られた結果から基準アンテナと各アンテナとの間のアナログ特性差を算出する。また、図2は、方法Bのキャリブレーションの概念図である。方法Bでは、無線機1は各アンテナと他の無線機(たとえば基地局2)との間で試験信号の送受信を行い、その結果からアンテナ間のアナログ特性差を算出する。基地局2において、TBSが付された構成要素は送信処理部(送信機)、RBSが付された構成要素は受信処理部(受信機)である。Embodiment 1 FIG.
Here, first, the prerequisite technology used in the calibration method of the present embodiment will be described. In the calibration method of the present embodiment, the calibration of the method A and the method B is used. FIG. 1 is a conceptual diagram of calibration of Method A. In this method A, thewireless device 1 transmits / receives a test signal between two antennas, and calculates an analog characteristic difference between the antennas from the result. In the wireless device 1, the component with T i is a transmission processing unit (transmitter) corresponding to the i-th (i = 1,..., M) antenna, and the component with R i is i. A reception processing unit (receiver) corresponding to the th antenna. FIG. 1 shows the case where the number of antennas is 2. However, when the number of antennas is 3, any one antenna is used as a reference antenna, and the test signal is transmitted between the reference antenna and another antenna. Transmission / reception is performed, and an analog characteristic difference between the reference antenna and each antenna is calculated from the obtained result. FIG. 2 is a conceptual diagram of the calibration of the method B. In the method B, the wireless device 1 transmits / receives a test signal between each antenna and another wireless device (for example, the base station 2), and calculates an analog characteristic difference between the antennas from the result. In the base station 2, component transmission processing unit T BS is attached (transmitter), the components R BS is attached is a reception processing unit (receiver).
ここでまず、本実施の形態のキャリブレーション方法で使用する前提技術についての説明を行う。本実施の形態のキャリブレーション方法では、方法Aおよび方法Bのキャリブレーションを使用する。図1は、方法Aのキャリブレーションの概念図である。この方法Aでは、無線機1は2つのアンテナ間で試験信号の送受信を行い、その結果からアンテナ間のアナログ特性差を算出する。無線機1において、Tiが付された構成要素はi番目(i=1,…,m)のアンテナに対応する送信処理部(送信機)であり、Riが付された構成要素はi番目のアンテナに対応する受信処理部(受信機)である。なお、図1は、アンテナ数が2の場合を示しているが、アンテナ数が3の場合には、いずれか1つのアンテナを基準アンテナとして、基準アンテナと他のアンテナとの間で試験信号の送受信を行い、得られた結果から基準アンテナと各アンテナとの間のアナログ特性差を算出する。また、図2は、方法Bのキャリブレーションの概念図である。方法Bでは、無線機1は各アンテナと他の無線機(たとえば基地局2)との間で試験信号の送受信を行い、その結果からアンテナ間のアナログ特性差を算出する。基地局2において、TBSが付された構成要素は送信処理部(送信機)、RBSが付された構成要素は受信処理部(受信機)である。
Here, first, the prerequisite technology used in the calibration method of the present embodiment will be described. In the calibration method of the present embodiment, the calibration of the method A and the method B is used. FIG. 1 is a conceptual diagram of calibration of Method A. In this method A, the
なお、従来から使用されている自己キャリブレーションは一般に電力依存性の問題を有しているが、本実施の形態で使用する方法Aは従来のいかなる自己キャリブレーション方法であっても構わない。また、従来から使用されている他の無線機を介してキャリブレーションを行う方法では一般に制御信号量が増加するが、本実施の形態で使用する方法Bは他の無線機を介して行う従来のいかなるキャリブレーション方法であっても構わない。
In addition, although the self-calibration conventionally used generally has a problem of power dependency, the method A used in the present embodiment may be any conventional self-calibration method. In addition, in the method of performing calibration through another wireless device that has been used conventionally, the amount of control signal generally increases, but the method B used in the present embodiment is the conventional method performed through another wireless device. Any calibration method may be used.
図3は、本実施の形態のキャリブレーション方法の概念を示す図である。図示したとおり、本実施の形態では、状況に応じて方法Aと方法Bを選択的又は適応的に使い分けてキャリブレーションを実施することを特徴とする。以下、本実施の形態のキャリブレーション方法の制御手順の一例を示すフローチャートである図4に基づいて、本実施の形態のキャリブレーション動作を説明する。
FIG. 3 is a diagram showing the concept of the calibration method of the present embodiment. As shown in the figure, this embodiment is characterized in that calibration is performed by selectively or adaptively using the method A and the method B depending on the situation. Hereinafter, the calibration operation of the present embodiment will be described based on FIG. 4 which is a flowchart showing an example of the control procedure of the calibration method of the present embodiment.
本実施の形態のキャリブレーション方法では、無線機(通信装置)1は、まず、温度特性が同等とみなせる時間内で、方法A(図1参照)による補正係数uAの算出および方法B(図2参照)による補正係数uBの算出を行う(ステップS1)。
In the calibration method according to the present embodiment, the wireless device (communication device) 1 first calculates the correction coefficient u A by the method A (see FIG. 1) and the method B (see FIG. 2), the correction coefficient u B is calculated (step S1).
無線機1は、つぎに、算出した2つの補正係数uAとuBを比較し、これらが類似しているかどうかを確認する(ステップS2)。
Next, the wireless device 1 compares the two calculated correction coefficients u A and u B and confirms whether they are similar (step S2).
そして、2つの補正係数が類似している場合(ステップS2,Yes)、方法Aにおける送信増幅器の電力依存性の影響は小さく方法Aを適用可能と判断し、方法Aにより算出した補正係数uAを採用する(ステップS3)。なお、補正係数が類似しているかどうかを判断する方法については後述する。また、温度変化を補償するため、一定時間が経過した時点で方法Aによる補正係数算出を行い、補正係数uAを更新する(ステップS4)。また、補正係数の算出方法を再選択する必要があるかどうかを確認し(ステップS5)。再選択の必要があれば(ステップS5,Yes)、ステップS1へ遷移する。一方、再選択の必要がなければ(ステップS5,No)、さらに一定時間が経過した時点で方法Aによる補正係数算出を行い、補正係数uAを更新する(ステップS4)。以降、補正係数の算出方法を再選択する必要があるとステップS5で判断するまで、ステップS4およびS5の処理を繰り返す。
If the two correction coefficients are similar (step S2, Yes), it is determined that the influence of the power dependency of the transmission amplifier in the method A is small and the method A can be applied, and the correction coefficient u A calculated by the method A is determined. Is adopted (step S3). A method for determining whether the correction coefficients are similar will be described later. Further, in order to compensate for the temperature change, the correction coefficient is calculated by the method A when a certain time has elapsed, and the correction coefficient u A is updated (step S4). Further, it is confirmed whether or not it is necessary to reselect the correction coefficient calculation method (step S5). If reselection is necessary (step S5, Yes), the process proceeds to step S1. On the other hand, if there is no need for reselection (step S5, No), the correction coefficient is calculated by the method A when a fixed time has passed and the correction coefficient u A is updated (step S4). Thereafter, the processes in steps S4 and S5 are repeated until it is determined in step S5 that the correction coefficient calculation method needs to be selected again.
これに対して、2つの補正係数が類似せずに大きく異なっている場合には(ステップS2,No)、方法Aにおける送信増幅器の電力依存性の影響が大きく方法Aを適用不可能と判断し、方法Bにより算出した補正係数uBを採用する(ステップS6)。また、温度変化を補償するため、一定時間が経過した時点で方法Bによる補正係数算出を行い、補正係数uBを更新する(ステップS7)。また、補正係数の算出方法を再選択する必要があるかどうかを確認し(ステップS8)。再選択の必要があれば(ステップS8,Yes)、ステップS1へ遷移する。一方、再選択の必要がなければ(ステップS8,No)、さらに一定時間が経過した時点で方法Bによる補正係数算出を行い、補正係数uBを更新する(ステップS7)。以降、補正係数の算出方法を再選択する必要があるとステップS8で判断するまで、ステップS7およびS8の処理を繰り返す。
On the other hand, when the two correction coefficients are not similar but greatly different (step S2, No), it is determined that the influence of the power dependency of the transmission amplifier in the method A is large and the method A is not applicable. Then, the correction coefficient u B calculated by the method B is employed (step S6). Further, in order to compensate for the temperature change, the correction coefficient is calculated by the method B when a certain time has elapsed, and the correction coefficient u B is updated (step S7). Further, it is confirmed whether or not it is necessary to reselect the correction coefficient calculation method (step S8). If reselection is necessary (step S8, Yes), the process proceeds to step S1. On the other hand, if there is no need for reselection (step S8, No), the correction coefficient is calculated by the method B when a certain time has passed and the correction coefficient u B is updated (step S7). Thereafter, the processes in steps S7 and S8 are repeated until it is determined in step S8 that the correction coefficient calculation method needs to be reselected.
ここで、補正係数とは送受信系アナログ特性差を補償する為にアンテナごとに個別に設定される値である。また、図5に示すように、通常、1番目のアンテナ(アンテナ#1)を基準とし、基準アンテナでは補正係数を1とする。その他のアンテナ(アンテナ#m)では基準アンテナと同じ送受信アナログ特性となるように補正係数を用いて送信信号又は受信信号を補正する。なお、上述した制御では、2アンテナの間のキャリブレーションを想定し、2番目のアンテナ(アンテナ#m)での補正係数をuA,uBとして示しているが、上記2アンテナの設定は単なる一例に過ぎず、3アンテナ以上の場合にも同様の概念を適用できる。
Here, the correction coefficient is a value that is individually set for each antenna in order to compensate for a transmission / reception system analog characteristic difference. Also, as shown in FIG. 5, the first antenna (antenna # 1) is normally used as a reference, and the correction coefficient is set to 1 for the reference antenna. The other antenna (antenna #m) corrects the transmission signal or the reception signal using the correction coefficient so that the same transmission / reception analog characteristics as the reference antenna are obtained. In the above-described control, the calibration between the two antennas is assumed, and the correction coefficients at the second antenna (antenna #m) are shown as u A and u B. This is just an example, and the same concept can be applied to the case of three or more antennas.
本実施の形態のキャリブレーション方法によれば、方法Aにおいて増幅器の電力依存性の問題が小さい場合には制御信号量の少ない方法Aを用い、電力依存性の影響が大きい場合には電力依存性の影響を受けない方法Bを用いる。このように、状況に応じて、方法Aと方法Bを使い分ける。その結果、方法Aのみを使用する従来法では増幅器の電力依存性の問題があったが、本実施の形態の方法では増幅器の電力依存性が問題とならない場合のみ方法Aを用いるため、増幅器の電力依存性の問題は発生しない。また、方法Bのみを使用する従来法と比較すると、本実施の形態では方法Aを適宜使用することによって制御信号量を抑えることができる。
According to the calibration method of the present embodiment, the method A with a small amount of control signal is used when the problem of the power dependency of the amplifier is small in the method A, and the power dependency when the influence of the power dependency is large. Method B that is not affected by the above is used. As described above, the method A and the method B are properly used depending on the situation. As a result, the conventional method using only the method A has a problem of power dependency of the amplifier. However, in the method of the present embodiment, the method A is used only when the power dependency of the amplifier does not matter. There is no power dependency problem. Compared with the conventional method using only method B, the amount of control signal can be suppressed by appropriately using method A in the present embodiment.
なお、通常は時間の経過とともに送受信系のアナログ特性が変化する。そのため、上述したように、キャリブレーションを繰返し実行することにより特性変動に追従させる。特にアナログ特性は温度変化に応じて変化しやすいが、通常1分程度は一定とみなすことができる。従って、上記ステップS4およびS7では、選定された方法(ステップS4では方法A、ステップS7では方法B)を例えば1分程度の時間周期で繰返し実行して補正係数を更新する。これに対して、ステップS1およびS2の処理すなわち、適用する方法を選択する処理は、ステップS4やS7において補正係数を更新する周期よりも十分長い周期(例えば1時間周期、1日周期など)で実行する。したがって、ステップS5およびS8では、方法選択が実施された後所定の周期(1分よりも十分長い1時間周期、1日周期など)が経過したかどうかを確認し、確認結果に応じて遷移先を決定する。また、適用する方法を選択する処理は、処理を実行してからの経過時間で判断するのではなく、無線機が移動し、通信の際に用いる送信電力が大きく変化した場合に行っても構わないし、経過時間による判断と送信電力による判断を併用しても構わない。このように、本実施の形態の方法を用いると、従来の方法Bより制御信号量を抑えつつ、増幅器の電力依存性の影響を受けないキャリブレーションが可能となる。
Note that the analog characteristics of the transmission / reception system usually change over time. Therefore, as described above, the calibration is repeatedly executed to follow the characteristic variation. In particular, the analog characteristics are likely to change according to the temperature change, but can usually be regarded as constant for about 1 minute. Accordingly, in steps S4 and S7, the selected method (method A in step S4, method B in step S7) is repeatedly executed, for example, in a time period of about 1 minute, and the correction coefficient is updated. On the other hand, the process of steps S1 and S2, that is, the process of selecting the method to be applied is a period (for example, 1 hour period, 1 day period, etc.) sufficiently longer than the period of updating the correction coefficient in steps S4 and S7. Execute. Therefore, in steps S5 and S8, it is confirmed whether or not a predetermined period (one hour period, one day period, etc. sufficiently longer than 1 minute) has elapsed after the method selection is performed, and the transition destination is determined according to the confirmation result. To decide. In addition, the process of selecting the method to be applied may be performed when the radio power has moved and the transmission power used for communication has changed greatly, instead of determining the elapsed time since the process was executed. Alternatively, determination based on elapsed time and determination based on transmission power may be used in combination. As described above, when the method of the present embodiment is used, it is possible to perform calibration without being affected by the power dependency of the amplifier while suppressing the control signal amount as compared with the conventional method B.
また、本実施の形態のキャリブレーション方法では、図6に示すように他の無線機(たとえば基地局2)に対して、方法Aと方法Bを切り替えるための情報を通知する必要がある。例えば、複数アンテナを持つ無線機1が基地局2とキャリブレーションを行う場合、無線機1は、まず方法Bによるキャリブレーションを基地局2に要請する要求信号を送信し、基地局2が無線機1からの要求信号を受信すると、無線機1と基地局2との間で方法Bによるキャリブレーションを実行する。また、無線機1は、独自に方法Aによるキャリブレーションも実行する。その後、無線機1は、方法Aと方法Bで得た2つの補正係数を比較して、いずれか一方を選択する(図4のステップS1およびS2の処理に相当)。方法Aで得られた補正係数を選択する場合、すなわち、以後方法Aを用いる場合(図4のステップS3~S5を実行する場合)、基地局2にキャリブレーション制御の停止を要求するキャリブレーション制御停止信号を送信する。基地局2はキャリブレーション制御停止信号を受信すると、方法Bによるキャリブレーションを停止し、以後、無線機1は方法Aによりキャリブレーションを一定周期ごとに行う。また、方法Bで得られた補正係数を選択する場合、すなわち、以後方法Bを用いる場合(図4のステップS6~S8を実行する場合)には、無線機1は基地局2にキャリブレーション制御の継続を要求するキャリブレーション制御継続信号を送信する。基地局2はキャリブレーション制御継続信号を受信すると、方法Bによるキャリブレーションを継続するため、特定の周期で無線機1との間で試験信号のやり取りを行い方法Bによるキャリブレーションを実行する。
Further, in the calibration method of the present embodiment, it is necessary to notify information for switching between method A and method B to another radio device (for example, base station 2) as shown in FIG. For example, when the wireless device 1 having a plurality of antennas performs calibration with the base station 2, the wireless device 1 first transmits a request signal for requesting the calibration by the method B to the base station 2, and the base station 2 transmits the wireless device. When the request signal from 1 is received, calibration by the method B is executed between the wireless device 1 and the base station 2. Further, the wireless device 1 also performs calibration by the method A independently. Thereafter, the wireless device 1 compares the two correction coefficients obtained by the method A and the method B, and selects one of them (corresponding to the processing in steps S1 and S2 in FIG. 4). When the correction coefficient obtained by the method A is selected, that is, when the method A is used thereafter (when steps S3 to S5 in FIG. 4 are executed), the calibration control that requests the base station 2 to stop the calibration control Send a stop signal. When the base station 2 receives the calibration control stop signal, the base station 2 stops the calibration by the method B, and thereafter, the radio device 1 performs the calibration by the method A at regular intervals. When the correction coefficient obtained by the method B is selected, that is, when the method B is used thereafter (when steps S6 to S8 in FIG. 4 are executed), the radio device 1 controls the base station 2 to perform calibration control. A calibration control continuation signal for requesting continuation of is transmitted. When the base station 2 receives the calibration control continuation signal, the base station 2 continues the calibration by the method B, so that the test signal is exchanged with the wireless device 1 at a specific cycle, and the calibration by the method B is executed.
このように、無線機1は方法A、方法Bの選定に応じてキャリブレーション制御の停止信号又は継続信号を基地局2に通知する。なお、ここでは一例として基地局2と無線機1の制御を示したが、いかなる2つの無線機間で上述の制御を行っても構わない。
As described above, the wireless device 1 notifies the base station 2 of a calibration control stop signal or continuation signal according to the selection of the method A and the method B. Although the control of the base station 2 and the wireless device 1 is shown here as an example, the above-described control may be performed between any two wireless devices.
つづいて、上述したステップS2において補正係数uAとuBが類似しているか大きく異なるかを判定する方法について、以下に示す。この判定方法としてはさまざまな方法が利用可能であるが、たとえば、次式(1)を用いて判定することができる。
Next, a method for determining whether the correction coefficients u A and u B are similar or greatly different in step S2 described above will be described below. Various methods can be used as this determination method. For example, the determination can be made using the following equation (1).
|uA/uB-1|<T …(1)
ここで、Tは閾値である。通常、uAとuBは複素数であるが、その比が1に近ければ補正係数uAとuBは類似しているとみなすことができる。従って、式(1)を満たす場合は補正係数が類似していると判断してステップS3~S5で示した制御を実行し、満たさない場合にはステップS6~S8で示した制御を実行する。この他にも本実施の形態では、さまざまな基準に基づき補正係数uAとuBの類似性を判定する方法が考えられる。 | u A / u B −1 | <T (1)
Here, T is a threshold value. Normally, u A and u B are complex numbers, but if the ratio is close to 1, the correction coefficients u A and u B can be regarded as similar. Therefore, if the equation (1) is satisfied, it is determined that the correction coefficients are similar, and the control shown in steps S3 to S5 is executed. If the equation (1) is not satisfied, the control shown in steps S6 to S8 is executed. In addition, in the present embodiment, a method of determining the similarity between the correction coefficients u A and u B based on various criteria can be considered.
ここで、Tは閾値である。通常、uAとuBは複素数であるが、その比が1に近ければ補正係数uAとuBは類似しているとみなすことができる。従って、式(1)を満たす場合は補正係数が類似していると判断してステップS3~S5で示した制御を実行し、満たさない場合にはステップS6~S8で示した制御を実行する。この他にも本実施の形態では、さまざまな基準に基づき補正係数uAとuBの類似性を判定する方法が考えられる。 | u A / u B −1 | <T (1)
Here, T is a threshold value. Normally, u A and u B are complex numbers, but if the ratio is close to 1, the correction coefficients u A and u B can be regarded as similar. Therefore, if the equation (1) is satisfied, it is determined that the correction coefficients are similar, and the control shown in steps S3 to S5 is executed. If the equation (1) is not satisfied, the control shown in steps S6 to S8 is executed. In addition, in the present embodiment, a method of determining the similarity between the correction coefficients u A and u B based on various criteria can be considered.
このように、本実施の形態では、電力依存性を有する場合にキャリブレーション精度が劣化するが他の無線機との間で試験用信号を送受信する必要がない方法Aのキャリブレーション方法と、電力依存性によるキャリブレーション精度の劣化はないが、他の無線機と試験信号を送受信するための制御信号が必要で処理が複雑な方法Bのキャリブレーション方法とを状況に応じて使い分けるようにした。具体的には、電力依存性のない場合には処理が簡単な自己キャリブレーション(方法A)を採用し、電力依存性があり方法Aでは十分な補正性能が得られない場合には、処理は複雑だが電力依存性の影響により補正精度が劣化することのない、他の無線機との通信を利用して行うキャリブレーション(方法B)を採用することとした。これにより、アンテナ間のアナログ特性差を効率的に補償するキャリブレーション方法を得ることができる。
As described above, in the present embodiment, the calibration method of the method A in which the calibration accuracy is deteriorated when the power dependency is present, but the test signal does not need to be transmitted to and received from another wireless device, and the power Although there is no deterioration in calibration accuracy due to dependency, the calibration method of Method B, which requires a control signal for transmitting and receiving test signals to and from other wireless devices and is complicated, is used depending on the situation. Specifically, when there is no power dependency, the self-calibration (method A) that is easy to process is adopted, and when there is power dependency and sufficient correction performance cannot be obtained by method A, the processing is The calibration (method B), which is complicated but does not degrade the correction accuracy due to the influence of power dependency, is performed using communication with other wireless devices (method B). As a result, a calibration method that efficiently compensates for the difference in analog characteristics between antennas can be obtained.
なお、本実施の形態では、2アンテナを想定したアンテナキャリブレーションを説明したが、Nアンテナ(N≧3)の場合には方法A,方法Bにおいてアンテナごとの補正係数ベクトルUA=[1,uA(2),uA(3),…,uA(N)]T,UB=[1,uB(2),uB(3),…,uB(N)]Tに対して、同等の制御が適用される。この場合、ベクトルUAとUBの類似性は、例えば次式(2)により判定できる。
In the present embodiment, the antenna calibration assuming two antennas has been described. However, in the case of N antennas (N ≧ 3), the correction coefficient vector U A = [1, u A (2), u A (3), ..., u A (N)] T , U B = [1, u B (2), u B (3), ..., u B (N)] T On the other hand, equivalent control is applied. In this case, the similarity between the vectors U A and U B can be determined by the following equation (2), for example.
|UA
HUB|/(|UA|・|UB|)>V …(2)
ここで、上付きのT(T),上付きのH(H)は、それぞれ転置,転置共役を表し、また、Vは閾値を表す。 | U A H U B | / (| U A | ・ | U B |)> V (2)
Here, superscript T ( T ) and superscript H ( H ) represent transposition and transposition conjugate, respectively, and V represents a threshold value.
ここで、上付きのT(T),上付きのH(H)は、それぞれ転置,転置共役を表し、また、Vは閾値を表す。 | U A H U B | / (| U A | ・ | U B |)> V (2)
Here, superscript T ( T ) and superscript H ( H ) represent transposition and transposition conjugate, respectively, and V represents a threshold value.
上式(2)の左辺は、ベクトルUAとUBの方向が近い場合にその値が大きくなる。従って、式2の左辺が一定の閾値Vよりも大きい場合にベクトルUAとUBを類似した状態とみなすことができる。
The value of the left side of the above equation (2) increases when the directions of the vectors U A and U B are close. Therefore, when the left side of Equation 2 is larger than a certain threshold value V, the vectors U A and U B can be regarded as similar states.
このように、本実施の形態のキャリブレーション方法は、3アンテナ以上のキャリブレーションを行う場合にも適用可能である。
As described above, the calibration method of the present embodiment can be applied to the case of performing calibration with three or more antennas.
実施の形態2.
つづいて、実施の形態2のキャリブレーション方法について説明する。実施の形態1で示したキャリブレーション方法は、利用する方法A(自己キャリブレーション)について特に言及せずに、いかなる手法を用いてもよいものとして説明を行ったが、本実施の形態では、この方法Aの一例について説明する。具体的には、使用する試験信号の受信品質を予測し、予測結果に応じて試験信号の長さを変更しながら方法Aを実施するキャリブレーション方法について説明する。Embodiment 2. FIG.
Next, the calibration method according to the second embodiment will be described. The calibration method described in the first embodiment has been described assuming that any method may be used without particularly mentioning the method A (self-calibration) to be used. An example of Method A will be described. Specifically, a calibration method is described in which the reception quality of the test signal to be used is predicted, and the method A is performed while changing the length of the test signal according to the prediction result.
つづいて、実施の形態2のキャリブレーション方法について説明する。実施の形態1で示したキャリブレーション方法は、利用する方法A(自己キャリブレーション)について特に言及せずに、いかなる手法を用いてもよいものとして説明を行ったが、本実施の形態では、この方法Aの一例について説明する。具体的には、使用する試験信号の受信品質を予測し、予測結果に応じて試験信号の長さを変更しながら方法Aを実施するキャリブレーション方法について説明する。
Next, the calibration method according to the second embodiment will be described. The calibration method described in the first embodiment has been described assuming that any method may be used without particularly mentioning the method A (self-calibration) to be used. An example of Method A will be described. Specifically, a calibration method is described in which the reception quality of the test signal to be used is predicted, and the method A is performed while changing the length of the test signal according to the prediction result.
図7は、実施の形態2のキャリブレーション方法を実現する無線機の構成例を示す図であり、上述した方法Aにおいて、受信品質予測を行い、キャリブレーションで使用する試験信号の長さを制御する無線機1aの構成例を示している。この無線機1aは、信号の送受信処理を行う送受信制御部11と、受信信号の電力を測定する電力測定部12と、試験信号の受信品質を予測する受信品質予測部13と、送信する試験信号の長さを決定する試験信号系列長決定部14と、キャリブレーション動作を実行する際の各種パラメータを設定するパラメータ制御部15と、を備える。
FIG. 7 is a diagram illustrating a configuration example of a radio that realizes the calibration method according to the second embodiment. In the method A described above, reception quality prediction is performed and the length of a test signal used for calibration is controlled. The example of a structure of the radio | wireless machine 1a to perform is shown. The wireless device 1a includes a transmission / reception control unit 11 that performs signal transmission / reception processing, a power measurement unit 12 that measures the power of a reception signal, a reception quality prediction unit 13 that predicts reception quality of a test signal, and a test signal to be transmitted. A test signal sequence length determination unit 14 that determines the length of the signal, and a parameter control unit 15 that sets various parameters when executing the calibration operation.
以下、図7を参照しながら、無線機1aが実行する方法A(自己キャリブレーション)について説明する。なお、キャリブレーション全体の動作は実施の形態1で説明したとおりである。
Hereinafter, the method A (self-calibration) performed by the wireless device 1a will be described with reference to FIG. The overall calibration operation is as described in the first embodiment.
無線機1aが自己キャリブレーションを行う場合、まず、電力測定部12が、後段の受信品質予測部13で受信品質を予測するために必要な電力測定データを収集する。例えば、電力測定部12は、無音区間の雑音電力(干渉電力を含む)の測定を行い、雑音電力の大きさを計算する。電力測定部12により電力測定データが収集されると、次に、受信品質予測部13が、電力測定データを用いてSNRやSINRなどの受信品質を予測する。受信品質の予測動作では、電力測定部12が計算した雑音電力データに加え、送信予定の信号の電力の大きさや、文献「能田,原,矢野,久保,“TDD方式における双方向チャネル測定を用いたアンテナアレー自己キャリブレーション”,信学技報 RCS2008-12, 2008年5月」に記載された減衰器(アッテネータ)に相当する減衰器を無線機1aが備えていれば、その減衰量(減衰率)を利用して、受信品質を予測する。なお、利用される減衰量は、たとえばパラメータ制御部15で保持されているので、それを取得する。受信信号電力は、たとえば、予定する送信電力(送信を予定している信号の電力)から無線局1aの複数アンテナ間の伝搬損、減衰器の減衰量をそれぞれ減算したものから見積もることができ、これと前述の雑音電力の測定結果からSNRを予測することができる。この予測結果は試験信号系列長決定部14に送られ、試験信号系列長決定部14は、受信品質予測部13から受け取った受信品質の予測結果(たとえばSNR)に基づいて、キャリブレーションで使用する試験信号のシンボル数を決定する。シンボル数は、たとえば、SNRと必要シンボル数の対照表を予め作成して保持しておき、この対照表と受信品質予測部13から受け取ったSNRを照らし合わせてシンボル数を決定する。決定したシンボル数はパラメータ制御部15で保持しておき、キャリブレーション実施時には、保持しておいたシンボル数の試験信号を使用する。
When the wireless device 1a performs self-calibration, first, the power measurement unit 12 collects power measurement data necessary for the reception quality prediction unit 13 in the subsequent stage to predict reception quality. For example, the power measurement unit 12 measures noise power (including interference power) in a silent section and calculates the magnitude of noise power. When power measurement data is collected by the power measurement unit 12, the reception quality prediction unit 13 next predicts reception quality such as SNR and SINR using the power measurement data. In the reception quality prediction operation, in addition to the noise power data calculated by the power measurement unit 12, the power level of the signal scheduled to be transmitted, and the literature “Noda, Hara, Yano, Kubo,“ bidirectional channel measurement in the TDD system are used. If the radio 1a is equipped with an attenuator (attenuator) described in "Antenna array self-calibration used", IEICE Technical Report RCS2008-12, May 2008, the amount of attenuation ( The reception quality is predicted using the attenuation rate. In addition, since the attenuation amount utilized is hold | maintained, for example in the parameter control part 15, it is acquired. The received signal power can be estimated from, for example, a value obtained by subtracting the propagation loss between the plurality of antennas of the radio station 1a and the attenuation amount of the attenuator from the planned transmission power (power of the signal scheduled to be transmitted), The SNR can be predicted from this and the noise power measurement result described above. This prediction result is sent to the test signal sequence length determination unit 14, and the test signal sequence length determination unit 14 uses it in calibration based on the reception quality prediction result (for example, SNR) received from the reception quality prediction unit 13. Determine the number of symbols in the test signal. For the number of symbols, for example, a comparison table of the SNR and the required number of symbols is created and held in advance, and the number of symbols is determined by comparing this comparison table with the SNR received from the reception quality prediction unit 13. The determined number of symbols is held in the parameter control unit 15, and the test signal having the number of held symbols is used during calibration.
なお、アンテナ数が3以上の場合には、基準のアンテナとキャリブレーション対象の各アンテナとの組み合わせそれぞれについて受信品質を予測し、組み合わせ毎に試験信号長(シンボル数)を決定するようにしてもよいし、制御が複雑化するのを回避したい場合には、いずれか一つの組み合わせについて受信品質の予測および試験信号長の決定を行い、決定した長さの試験信号をすべての組み合わせで固定的に使用するようにしてもよい。
When the number of antennas is 3 or more, the reception quality is predicted for each combination of the reference antenna and each antenna to be calibrated, and the test signal length (number of symbols) is determined for each combination. If you want to avoid complication of control, predict the reception quality and determine the test signal length for any one combination, and fix the test signal of the determined length in all combinations. It may be used.
このように、本実施の形態では、キャリブレーションを行う無線機が、試験信号の受信品質を予測し、その予測結果に応じた長さの試験信号を使用してキャリブレーション処理を行うこととした。これにより、たとえば、キャリブレーション時の試験信号の受信SNRが悪い場合には、それに対応して試験信号のシンボル数を増やしてキャリブレーション処理を実施するので、必要な精度を確保することが可能となる。また、十分な受信SNRが得られる場合には、不必要なシンボル数の送信を抑え、キャリブレーション処理の実施に伴って発生する通信断の時間を短縮化するなどの効果を得ることができる。
As described above, in the present embodiment, the radio that performs calibration predicts the reception quality of the test signal, and performs the calibration process using the test signal having a length corresponding to the prediction result. . As a result, for example, when the reception SNR of the test signal at the time of calibration is poor, the number of symbols of the test signal is correspondingly increased and the calibration process is performed, so that necessary accuracy can be ensured. Become. Further, when a sufficient reception SNR can be obtained, it is possible to obtain an effect such as suppressing transmission of an unnecessary number of symbols and shortening a communication disconnection time that occurs when the calibration process is performed.
また、試験信号系列長決定部14で使用する対照表を、使用予定の変調方式によって切り替えることで、キャリブレーション後のデータ通信時に使用する変調方式によって、必要となる補正係数の精度を変化させることができ、例えば信号点間距離が小さく、より高いキャリブレーション精度が要求される変調方式を利用するシステムや、適応変調を使用するシステムでも、変調方式と予測した受信品質によって精度を制御して、キャリブレーション精度を原因とする通信効率の低下を防ぐことが可能になる。
In addition, by changing the comparison table used in the test signal sequence length determination unit 14 according to the modulation method to be used, the accuracy of the necessary correction coefficient is changed depending on the modulation method used at the time of data communication after calibration. For example, even in a system that uses a modulation scheme that requires a small calibration distance and a higher calibration accuracy, and a system that uses adaptive modulation, the accuracy is controlled by the modulation scheme and the predicted reception quality, It is possible to prevent a decrease in communication efficiency due to calibration accuracy.
なお、本実施の形態では、受信品質を予測する方法として、無音区間の電力測定結果を利用して予測する方法を適用した場合について説明したが、これ以外に、定期的にキャリブレーションを行うシステムにおいては前回のキャリブレーション時の受信電力を利用する方法や、直近のデータ通信時における受信電力を利用する方法、通信相手となる無線局から受信電力やSNRを送信してもらい、それを利用する方法(例えば、同機種間で通信しており、送信電力が既知であり、アンテナ間の伝搬路可逆性が成り立っていれば、通信相手となる無線局の受信電力、雑音電力、SNRなどから自局の受信品質を見積もることができる)なども適用可能であり、また、これらを組み合わせて受信品質を予測するようにしてもよい。
In the present embodiment, the case where a method of predicting using the power measurement result of the silent section is applied as a method of predicting the reception quality has been described. However, in addition to this, a system that performs calibration periodically In the method of using the received power at the time of the previous calibration, the method of using the received power at the time of the most recent data communication, and receiving the received power and SNR from the wireless station that is the communication partner, and using it Method (for example, if communication is performed between the same model, the transmission power is known, and the propagation path reversibility between antennas is established, the reception power, noise power, SNR, etc. The reception quality of the station can be estimated), and the reception quality may be predicted by combining these.
実施の形態3.
つづいて、実施の形態3のキャリブレーション方法について説明する。実施の形態2では、方法Aで使用する試験信号の長さを可変とする場合について説明を行ったが、本実施の形態では、方法B(他の無線機を介して行うキャリブレーション)で使用する試験信号の長さを可変とする場合について説明する。Embodiment 3 FIG.
Next, the calibration method according to the third embodiment will be described. In the second embodiment, the case where the length of the test signal used in the method A is variable has been described. However, in the present embodiment, the test signal is used in the method B (calibration performed through another wireless device). A case where the length of the test signal to be made is variable will be described.
つづいて、実施の形態3のキャリブレーション方法について説明する。実施の形態2では、方法Aで使用する試験信号の長さを可変とする場合について説明を行ったが、本実施の形態では、方法B(他の無線機を介して行うキャリブレーション)で使用する試験信号の長さを可変とする場合について説明する。
Next, the calibration method according to the third embodiment will be described. In the second embodiment, the case where the length of the test signal used in the method A is variable has been described. However, in the present embodiment, the test signal is used in the method B (calibration performed through another wireless device). A case where the length of the test signal to be made is variable will be described.
以下、図8~図10を参照しながら、本実施の形態の無線機が実行する方法B(他の無線機を介して行うキャリブレーション)について説明する。なお、図8~図10は、実施の形態3のキャリブレーション方法で利用する方法Bの動作手順を示す図であり、これらの図では、一例として、複数のアンテナを備えた無線機(方法Aも併せて実施する無線機)が、基地局を他の無線機とみなして方法Bを実行する場合の動作手順を示している。図8は、試験信号の受信品質予測および試験信号長の決定を無線機側で行う場合の手順を示し、図9は、試験信号の受信品質予測を無線機側で行い、試験信号長の決定を基地局側で行う場合の手順を示し、図10は、試験信号の受信品質予測および試験信号長の決定を基地局側で行う場合の手順を示している。また、図8~図10において、同じ処理には同じステップ番号を付している。
Hereinafter, the method B (calibration performed through another radio) executed by the radio according to the present embodiment will be described with reference to FIGS. 8 to 10 are diagrams showing an operation procedure of the method B used in the calibration method of the third embodiment. In these drawings, as an example, a radio (method A) having a plurality of antennas is shown. FIG. 4 shows an operation procedure in the case where the radio apparatus) also executes the method B while regarding the base station as another radio apparatus. FIG. 8 shows a procedure when the reception quality prediction of the test signal and the determination of the test signal length are performed on the wireless device side, and FIG. 9 performs the reception quality prediction of the test signal on the wireless device side to determine the test signal length. FIG. 10 shows the procedure when the reception quality prediction of the test signal and the determination of the test signal length are performed on the base station side. In FIG. 8 to FIG. 10, the same step number is assigned to the same process.
まず、図8に示した、試験信号の受信品質予測および試験信号長の決定を無線機側で行う場合の手順について説明する。
First, a description will be given of the procedure in the case where the reception quality prediction of the test signal and the determination of the test signal length shown in FIG.
図8に示した手順では、まず、無線機が受信電力測定を行い(ステップS11)、次に、この結果に基づく受信品質推定を行い(ステップS12)、さらに、受信品質推定結果に基づく試験信号系列長決定を行う(ステップS13)。なお、これらの各ステップで実行する処理は、実施の形態2で説明した電力測定部12、受信品質予測部13および試験信号系列長決定部14がそれぞれ実行する処理と同じである。この後、決定した系列長を指定する信号を基地局に送信し(ステップS14)、基地局は、無線機で決定された長さの試験信号を無線機へ送信する(ステップS15)。また、無線機は、ステップS13で決定した長さの試験信号を基地局へ送信する(ステップS16)。そして、基地局は、無線機から送信された試験信号の測定結果を無線機にフィードバックし(ステップS17)、無線機は、フィードバックされた測定結果、およびステップS15で基地局から送信された試験信号の受信結果に基づいて補正係数を算出する(ステップS18)。
In the procedure shown in FIG. 8, first, the wireless device performs reception power measurement (step S11), then performs reception quality estimation based on this result (step S12), and further, a test signal based on the reception quality estimation result. A sequence length is determined (step S13). Note that the processing executed in each of these steps is the same as the processing executed by the power measurement unit 12, the reception quality prediction unit 13, and the test signal sequence length determination unit 14 described in the second embodiment. Thereafter, a signal designating the determined sequence length is transmitted to the base station (step S14), and the base station transmits a test signal having a length determined by the wireless device to the wireless device (step S15). Further, the radio transmits a test signal having a length determined in step S13 to the base station (step S16). Then, the base station feeds back the measurement result of the test signal transmitted from the radio device to the radio device (step S17), and the radio device returns the measurement result fed back and the test signal transmitted from the base station in step S15. The correction coefficient is calculated based on the reception result (step S18).
以上の手順で方法Bを行うことにより、実施の形態2で示したキャリブレーションと同様に、受信品質に応じた長さの試験信号にて行うキャリブレーションが実現され、たとえば、無線機の試験信号受信時のSNRが小さい場合においても、それに応じた系列長で試験信号を送受信し、必要な精度でキャリブレーションを行うことができるようになる。
By performing the method B according to the above procedure, the calibration performed with the test signal having a length corresponding to the reception quality is realized in the same manner as the calibration shown in the second embodiment. Even when the SNR at the time of reception is small, the test signal can be transmitted and received with the corresponding sequence length, and calibration can be performed with the required accuracy.
図9に示した手順では、上述したステップS11およびS12を実行すると、無線機は、ステップS12を実行して得られた受信品質(受信品質推定結果)を基地局へ通知し(ステップS21)、この通知された受信品質に基づいて、基地局が試験信号の長さ(試験信号系列長)を決定する(ステップS22)。このステップS22において、基地局は、実施の形態2で示した試験信号系列長決定部14が試験信号系列長を決定する手順と同様の手順にて、試験信号系列長を決定する。基地局が試験信号系列長を決定した後は、既に説明したステップS15~S18を実行する。この場合、無線機は、受信する試験信号の系列長を基地局から予め通知してもらう、または信号に含まれる固有の系列を試験信号の始点および終端と規定しておく、などの方法で試験信号の長さを検知して動作する。
In the procedure shown in FIG. 9, when performing steps S11 and S12 described above, the radio notifies the base station of the reception quality (reception quality estimation result) obtained by executing step S12 (step S21). Based on the notified reception quality, the base station determines the length of the test signal (test signal sequence length) (step S22). In this step S22, the base station determines the test signal sequence length in the same procedure as the test signal sequence length determination unit 14 shown in Embodiment 2 determines the test signal sequence length. After the base station determines the test signal sequence length, steps S15 to S18 already described are executed. In this case, the radio device performs a test such as having the base station notify the sequence length of the test signal to be received in advance, or defining the unique sequence included in the signal as the start and end points of the test signal. Operates by detecting the length of the signal.
なお、図9に示した手順では、無線機側が受信電力測定結果などから受信品質推定し、得られた受信品質推定結果を基地局へ通知するようにしているが、無線機は、受信電力測定結果をそのまま基地局へ送信し、基地局側では、通知された受信電力測定結果に基づいて受信品質を推定した上でステップS22を実行するようにしてもよい。
In the procedure shown in FIG. 9, the radio side estimates the reception quality from the reception power measurement result and notifies the base station of the obtained reception quality estimation result. The result may be transmitted to the base station as it is, and the base station may execute step S22 after estimating the reception quality based on the notified reception power measurement result.
図10に示した手順では、基地局が、上記のステップS11と同様の処理を実行して受信電力を測定し(ステップS31)、さらに、上記のステップS12と同様の処理を実行して受信品質を推定する(ステップS32)。そして、基地局は、ステップS32を実行して得られた受信品質推定結果を用いて、既に説明したステップS22を実行する。これ以降は、図8や図9に示した手順と同様に、ステップS15~S18を実行する。
In the procedure shown in FIG. 10, the base station executes the same process as in step S11 above to measure the received power (step S31), and further executes the same process as in step S12 above to receive the reception quality. Is estimated (step S32). And a base station performs step S22 already demonstrated using the reception quality estimation result obtained by performing step S32. Thereafter, steps S15 to S18 are executed in the same manner as the procedure shown in FIGS.
なお、図示を省略しているが、上記ステップS31に先立って、無線機は基地局に対して、試験信号系列長を決定した上で方法Bのキャリブレーション処理を開始するように指示を行う。これとは逆に、基地局が自律的に試験信号系列長を決定し、方法Bのキャリブレーション処理を開始する旨を無線機へ通知した上で上記手順を実行するようにしてもよい。また、図9に示した手順で動作する場合と同様に、無線機は、受信する試験信号の系列長を基地局から予め通知してもらう、または信号に含まれる固有の系列を試験信号の始点および終端と規定しておく、などの方法で試験信号の長さを検知して動作する。
Although not shown, prior to step S31, the radio instructs the base station to start the calibration process of method B after determining the test signal sequence length. On the contrary, the base station may autonomously determine the test signal sequence length and notify the radio device that the calibration process of method B is started, and then execute the above procedure. Similarly to the case of operating according to the procedure shown in FIG. 9, the radio apparatus notifies the base station of the sequence length of the test signal to be received in advance, or the unique sequence included in the signal is the starting point of the test signal. And, it operates by detecting the length of the test signal by a method such as prescribing as termination.
基地局と無線機のアンテナ間が可逆な通信路で、無線機側での雑音の大きさ(雑音電力)や送信電力が何らかの方法により基地局側で既知の場合、基地局は、受信電力測定結果から無線機の受信品質結果を予想することができるので、図10に示した手順が採用可能となる。
When the base station and the radio antenna are reversible communication paths, and the noise level (noise power) and transmission power on the radio side are known on the base station side by some method, the base station measures the received power. Since the reception quality result of the radio can be predicted from the result, the procedure shown in FIG. 10 can be adopted.
図9または図10に示し手順で方法Bを行う場合にも、図8に示した手順で方法Bを行う場合と同様の効果が得られる。
When the method B is performed according to the procedure shown in FIG. 9 or FIG. 10, the same effect as that obtained when the method B is performed according to the procedure shown in FIG.
なお、当然ながら、本実施の形態で示した手順によるキャリブレーション(方法B)と実施の形態2で示したキャリブレーション(方法A)を組み合わせることも可能であり、組み合わせた場合には、方法Aと方法Bのいずれを実行する場合においても、受信品質に応じた長さの試験信号を使用して、必要な精度でキャリブレーションを行うことができるようになる。この結果、さらに効率的なキャリブレーションが可能となる。
Of course, it is also possible to combine the calibration (method B) according to the procedure shown in the present embodiment and the calibration (method A) shown in the second embodiment. In both cases, the calibration can be performed with a required accuracy by using a test signal having a length corresponding to the reception quality. As a result, more efficient calibration becomes possible.
以上のように、本発明にかかるキャリブレーション方法は、複数アンテナを使用して行う無線通信に有用であり、特に、無線機が、アンテナ間の送受信系アナログ特性差を効率的に補償する場合に適している。
As described above, the calibration method according to the present invention is useful for wireless communication using a plurality of antennas, particularly when the wireless device efficiently compensates for a difference in transmission / reception system analog characteristics between antennas. Is suitable.
Claims (12)
- TDD方式で通信を行う複数のアンテナを備えた無線機が、各アンテナのキャリブレーションを行う場合のキャリブレーション方法であって、
無線機単独でアンテナキャリブレーションを行うことにより第1の補正係数を算出する第1のキャリブレーションステップと、
他の無線機との通信を利用したアンテナキャリブレーションを行うことにより第2の補正係数を算出する第2のキャリブレーションステップと、
前記第1の補正係数と前記第2の補正係数のいずれか一方を状況に応じて選択し、最終的な補正係数とする補正係数選択ステップと、
を含むことを特徴とするキャリブレーション方法。 A calibration method in a case where a radio device having a plurality of antennas that perform communication using the TDD method calibrates each antenna,
A first calibration step of calculating a first correction coefficient by performing antenna calibration by the radio alone;
A second calibration step of calculating a second correction coefficient by performing antenna calibration using communication with another wireless device;
A correction coefficient selection step of selecting any one of the first correction coefficient and the second correction coefficient depending on the situation, and setting it as a final correction coefficient;
A calibration method comprising: - 前記補正係数選択ステップでは、前記第1の補正係数と前記第2の補正係数を比較し、比較結果に基づいていずれか一方の補正係数を選択することを特徴とする請求項1に記載のキャリブレーション方法。 2. The calibration according to claim 1, wherein in the correction coefficient selection step, the first correction coefficient and the second correction coefficient are compared, and one of the correction coefficients is selected based on the comparison result. Method.
- 前記比較結果が前記第1の補正係数と前記第2の補正係数が類似していることを示す場合、前記第1の補正係数を最終的な補正係数として選択することを特徴とする請求項2に記載のキャリブレーション方法。 3. The first correction coefficient is selected as a final correction coefficient when the comparison result indicates that the first correction coefficient and the second correction coefficient are similar to each other. Calibration method described in 1.
- 前記補正係数選択ステップにおける選択結果に従い、前記無線機単独で行うアンテナキャリブレーションである第1のキャリブレーションまたは前記他の無線機との通信を利用して行うアンテナキャリブレーションである第2のキャリブレーションを定期的に実行し、前記最終的な補正係数を更新する補正係数更新ステップ、
をさらに含むことを特徴とする請求項1に記載のキャリブレーション方法。 According to the selection result in the correction coefficient selection step, the first calibration which is antenna calibration performed by the radio alone or the second calibration which is antenna calibration performed using communication with the other radio Periodically performing a correction coefficient updating step for updating the final correction coefficient,
The calibration method according to claim 1, further comprising: - 前記補正係数選択ステップにおいて前記第1の補正係数を選択した場合、前記第1のキャリブレーションを定期的に実行し、また、前記補正係数選択ステップにおいて前記第2の補正係数を選択した場合には、前記第2のキャリブレーションを定期的に実行することを特徴とする請求項4に記載のキャリブレーション方法。 When the first correction coefficient is selected in the correction coefficient selection step, the first calibration is periodically executed, and when the second correction coefficient is selected in the correction coefficient selection step The calibration method according to claim 4, wherein the second calibration is periodically executed.
- 前記補正係数更新ステップを実行するにあたっては、前記補正係数選択ステップによる選択結果に応じた制御信号を前記他の無線機に対して送信することにより、前記第2のキャリブレーションを行うための動作が必要かどうかを当該他の無線機に対して通知することを特徴とする請求項4または5に記載のキャリブレーション方法。 In executing the correction coefficient update step, an operation for performing the second calibration is performed by transmitting a control signal corresponding to the selection result in the correction coefficient selection step to the other radio device. 6. The calibration method according to claim 4 or 5, wherein whether or not it is necessary is notified to the other wireless device.
- 前記第1のキャリブレーションステップは、
キャリブレーションを行うアンテナ間で試験信号を送受信する際の信号受信品質を予測する受信品質予測ステップと、
前記受信品質予測ステップにおける予測結果に基づいて、キャリブレーションで使用する試験信号の長さを決定する試験信号長決定ステップと、
前記試験信号長決定ステップで決定した長さの試験信号を前記アンテナ間で送受信することによりキャリブレーションを行うキャリブレーション実行ステップと、
を含むことを特徴とする請求項1に記載のキャリブレーション方法。 The first calibration step includes
A reception quality prediction step for predicting a signal reception quality when a test signal is transmitted and received between antennas for calibration;
A test signal length determination step for determining a length of a test signal used in calibration based on a prediction result in the reception quality prediction step;
A calibration execution step for performing calibration by transmitting and receiving the test signal of the length determined in the test signal length determination step between the antennas;
The calibration method according to claim 1, further comprising: - 前記第2のキャリブレーションステップは、
前記他の無線機との間で試験信号を送受信する際の信号受信品質を予測する受信品質予測ステップと、
前記受信品質予測ステップにおける予測結果に基づいて、キャリブレーションで使用する試験信号の長さを決定する試験信号長決定ステップと、
前記試験信号長決定ステップで決定した長さの試験信号を前記他の無線機との間で送受信することによりキャリブレーションを行うキャリブレーション実行ステップと、
を含むことを特徴とする請求項1に記載のキャリブレーション方法。 The second calibration step includes
A reception quality prediction step of predicting a signal reception quality when transmitting / receiving a test signal to / from the other wireless device;
A test signal length determination step for determining a length of a test signal used in calibration based on a prediction result in the reception quality prediction step;
A calibration execution step of performing calibration by transmitting and receiving the test signal of the length determined in the test signal length determination step to and from the other wireless device;
The calibration method according to claim 1, further comprising: - 前記第2のキャリブレーションステップは、
前記他の無線機との間で試験信号を送受信する際の信号受信品質を予測する受信品質予測ステップと、
前記受信品質予測ステップにおける予測結果を前記他の無線機に通知し、当該通知した予測結果に基づいて、キャリブレーションで使用する試験信号の長さを決定するように指示する試験信号長決定指示ステップと、
前記指示に伴い前記他の無線機で決定された長さの試験信号を当該他の無線機との間で送受信することによりキャリブレーションを行うキャリブレーション実行ステップと、
を含むことを特徴とする請求項1に記載のキャリブレーション方法。 The second calibration step includes
A reception quality prediction step of predicting a signal reception quality when transmitting / receiving a test signal to / from the other wireless device;
Test signal length determination instruction step for notifying the other wireless device of the prediction result in the reception quality prediction step and instructing to determine the length of the test signal used in calibration based on the notified prediction result When,
A calibration execution step for performing calibration by transmitting / receiving a test signal having a length determined by the other wireless device according to the instruction to / from the other wireless device;
The calibration method according to claim 1, further comprising: - 前記第2のキャリブレーションステップは、
前記他の無線機との間で試験信号を送受信する際の信号受信品質を予測するために必要な、雑音電力を測定する電力測定ステップと、
前記測定した雑音電力を前記他の無線機に通知し、当該通知した雑音電力に基づいて、キャリブレーションで使用する試験信号の長さの決定を行うように指示する試験信号長決定指示ステップと、
前記指示に伴い前記他の無線機で決定された長さの試験信号を当該他の無線機との間で送受信することによりキャリブレーションを行うキャリブレーション実行ステップと、
を含むことを特徴とする請求項1に記載のキャリブレーション方法。 The second calibration step includes
A power measurement step for measuring noise power necessary for predicting signal reception quality when transmitting / receiving a test signal to / from the other radio device;
A test signal length determination instruction step for notifying the other wireless device of the measured noise power and instructing to determine the length of the test signal used in calibration based on the notified noise power;
A calibration execution step for performing calibration by transmitting / receiving a test signal having a length determined by the other wireless device according to the instruction to / from the other wireless device;
The calibration method according to claim 1, further comprising: - 前記第2のキャリブレーションステップは、
前記他の無線機に対して、自身との間で試験信号を送受信する際の信号受信品質を予測し、予測結果に基づいてキャリブレーションで使用する試験信号の長さを決定するように指示する試験信号長決定指示ステップと、
前記指示に伴い前記他の無線機で決定された長さの試験信号を当該他の無線機との間で送受信することによりキャリブレーションを行うキャリブレーション実行ステップと、
を含むことを特徴とする請求項1に記載のキャリブレーション方法。 The second calibration step includes
Instructs the other wireless device to predict the signal reception quality when transmitting / receiving the test signal to / from itself and to determine the length of the test signal to be used for calibration based on the prediction result A test signal length determination instruction step;
A calibration execution step for performing calibration by transmitting / receiving a test signal having a length determined by the other wireless device according to the instruction to / from the other wireless device;
The calibration method according to claim 1, further comprising: - 請求項1~11のいずれか一つに記載の複数のアンテナを備えた無線機として動作することを特徴とする通信装置。 A communication device that operates as a wireless device including a plurality of antennas according to any one of claims 1 to 11.
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JP2017507611A (en) * | 2014-03-04 | 2017-03-16 | クゥアルコム・インコーポレイテッドQualcomm Incorporated | Analog embedded self-test transceiver |
KR20200034251A (en) * | 2018-09-21 | 2020-03-31 | 주식회사 이노와이어리스 | method for calibrating I/Q imbalance of massive air-channel simulator |
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JP2003218621A (en) * | 2002-01-21 | 2003-07-31 | Nec Corp | Apparatus and method for calibrating array antenna |
JP2003229797A (en) * | 2002-01-31 | 2003-08-15 | Matsushita Electric Ind Co Ltd | Array antenna transmitting apparatus and characteristic error correction method |
JP2005328571A (en) * | 2005-07-25 | 2005-11-24 | Sanyo Electric Co Ltd | Radio terminal device, and method and program for transmission directivity calibration |
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JP2003218621A (en) * | 2002-01-21 | 2003-07-31 | Nec Corp | Apparatus and method for calibrating array antenna |
JP2003229797A (en) * | 2002-01-31 | 2003-08-15 | Matsushita Electric Ind Co Ltd | Array antenna transmitting apparatus and characteristic error correction method |
JP2005328571A (en) * | 2005-07-25 | 2005-11-24 | Sanyo Electric Co Ltd | Radio terminal device, and method and program for transmission directivity calibration |
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JP2017507611A (en) * | 2014-03-04 | 2017-03-16 | クゥアルコム・インコーポレイテッドQualcomm Incorporated | Analog embedded self-test transceiver |
KR20200034251A (en) * | 2018-09-21 | 2020-03-31 | 주식회사 이노와이어리스 | method for calibrating I/Q imbalance of massive air-channel simulator |
KR102129270B1 (en) | 2018-09-21 | 2020-07-02 | 주식회사 이노와이어리스 | method for calibrating I/Q imbalance of massive air-channel simulator |
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