KR101706204B1 - Method of correcting transceiver of radio channel measurement system with multiple antennas - Google Patents

Abstract

The present invention relates to a transmission path correcting method in a multi-antenna radio channel measuring system, and more particularly, to a single path forming step of connecting a front end or a rear end of a transmitting end of a multi- Measuring a transmission and reception signal of a baseband by switching and operating a path of the multi-antenna radio channel measurement system having the single path; analyzing the measured transmission and reception signals to derive a size and a phase change caused by the transmission and reception path; And a path correction step of correcting a transmission / reception path of the radio channel measurement system using the derived size and phase value.

Multi-antenna, wireless channel measurement, path compensation

Description

[0001] The present invention relates to a method for correcting a transmission path in a multi-antenna wireless channel measurement system,

[0001] The present invention relates to a method for correcting transmission / reception paths in a multi-antenna radio channel measurement system, and more particularly, to a method and apparatus for directly measuring a signal in a single- And a method for correcting phase values.

Modeling of wireless channel to be used in mobile communication is needed when developing mobile communication system. The radio channel modeling is performed by first measuring a radio channel and then extracting parameters of the radio channel using the measured data. Therefore, in the modeling, a wireless channel measurement device (channel sounder) is required for measuring a wireless channel.

Particularly, in a radio channel measurement system using multiple antennas, a multi-antenna arrangement is used, and a received signal for each antenna element received through a radio channel is analyzed to determine an angle of departure (AoD) And the directionality of the wave such as the angle of arrival (AoA) can be measured.

However, the received signal reflects not only the characteristics of the radio channel, but also the characteristics of each path in the transmitting and receiving antenna system. However, characteristics of paths in the system corresponding to the antenna elements of the multiple antennas are different from each other. Therefore, if the characteristic of the path corresponding to each antenna element of multiple antennas is not corrected, an error occurs in the measurement of the starting angle and the arrival angle of the radio channel.

Therefore, the relative size and phase characteristics of signals in each system path connected to each antenna must be corrected in the measured values in order to eliminate errors occurring in the measurement of the start angle and the arrival angle of the wireless channel.

As a method for solving the above problems, there has been proposed a method of correcting a characteristic of a system by wirelessly transmitting / receiving a signal at a predetermined position with a separate calibration transmitter or calibration receiver.

However, the above method has a problem that it is possible only in a specific situation where there is no change in the radio channel.

Also, as a correction method in a radio channel measurement system using multiple antennas, conventionally, a method has been proposed in which a reference signal is radiated and a reflection signal for an arbitrary reference point is received and corrected using a received signal.

However, the above method has a problem in that it is not easy to determine an accurate reference point in a radio channel measurement system for measuring various mobile communication channel environments (indoors and outdoors).

Thus, the conventional techniques have a problem in correcting the transmission / reception path for each antenna element of multiple antennas when measuring a radio channel.

In order to solve the above problems, the present invention provides a radio channel measurement system for measuring relative size and phase change of each antenna element of a multi-antenna array according to a transmission / reception path and correcting a transmission / And an object of the present invention is to provide a transmission / reception path correction method in a multi-antenna radio channel measurement system capable of performing multi-antenna radio channel measurement.

As a means for solving the above problems, a transmitting / receiving path correcting method in a multi-antenna radio channel measuring system according to an embodiment of the present invention is characterized in that a front end or a rear end of a transmitting end of a multi- A single path forming step of forming and connecting a single path, a signal measuring step of measuring a transmission / reception signal of a baseband by switching and operating the multi-antenna radio channel measurement system formed with the single path, and analyzing the measured transmission / A signal analysis step of deriving a magnitude and a phase change caused by the transmission / reception path, and a path correction step of correcting a transmission / reception path of the radio channel measurement system using the derived magnitude and phase value.

According to the apparatus for correcting a transmission / reception path in the radio channel measurement system of the present invention, transmission / reception path characteristics can be measured using a loopback circuit or an attenuator and corrected for transmission / reception paths in the radio channel measurement system using multiple antennas.

In a wireless channel measurement system using multiple antennas in a circular array composed of isotropic antennas, the transmission and reception path characteristics including the measurement system, the antenna and the feeder line can be measured and corrected.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the detailed description of known functions and configurations incorporated herein will be omitted when it may unnecessarily obscure the subject matter of the present invention.

In order to clearly illustrate the present invention, parts not related to the description are omitted, and like parts are denoted by similar reference numerals throughout the specification.

Also, when a part is referred to as "including " an element, it does not exclude other elements unless specifically stated otherwise.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a flowchart of a transmission / reception path correction method in a multi-antenna wireless channel measurement system according to the present invention.

Referring to FIG. 1, a transmission path correcting method in a multi-antenna wireless channel measurement system includes a single path forming step S100, a signal measuring step S200, a signal analyzing step S300, and a path compensating step S400 .

In the single path forming step S100, the front end or the rear end of the transmitting end is connected to the front end or the rear end of the receiving end by forming a single path in order to measure the characteristics of the transmission end end path. In order to form a single path, the front end or the rear end of the transmitting end and the front end or the rear end of the receiving end can be connected using a loopback circuit.

In the above measurement, the power distributor is used to make a plurality of transmission / reception paths into a single path, and the attenuator is used to attenuate the transmission signal to reduce the reception signal to a range suitable for measurement.

In the signal measurement step (S200), the multi-antenna radio channel measurement system having the single path is operated by switching the power supply switch of the transmitting and receiving end and measuring the signals transmitted and received in each path in the baseband.

In the signal analysis step (S300), the transmission and reception signals measured in the signal measurement step (S300) are analyzed to obtain relative sizes and phases generated by the respective transmission and reception paths. The analysis of the signal can be obtained by comparing the magnitude and phase of the transmission signal and the reception signal.

In the path correction step (S400), the transmission / reception path of the multi-antenna radio channel measurement system is corrected using the obtained relative size and phase. The correction of the path is made by calculating the relative size and phase of the transmission / reception path when the wireless channel measurement system calculates the start angle and the arrival angle of the wireless channel.

FIG. 2 is a diagram illustrating an embodiment of applying a transmission / reception path correction method in a multi-antenna wireless channel measurement system of the present invention.

In the single path forming step S100, as shown in FIG. 2, the rear end of the transmitting end and the rear end of the receiving end are connected through an array antenna.

In the signal measurement step S200, the transmission power splitter 104 and the reception power splitter 105 shown in FIG. 2 first fix the switch to an arbitrary antenna element. After applying a 'K' signal to the input, measure the signal at the input and output of the baseband.

When the signal measurement is completed for one path, the switches of the transmission power divider 104 and the reception power splitter 105 are switched, and signals are also measured for the transmission / reception path of other antenna elements.

In the signal analysis step (S300), signals of points B and C for the measured transmission / reception paths are analyzed.

The relative magnitude and phase occurring in the transmission path from the transmission power amplifier 103 to the m-th antenna array element and the reception path from the m-th antenna array reception path to the low noise receiver 106 shown in FIG. 2 are denoted by K _m and θ _m , signals at points A, B, C, and D can be expressed as follows.

Signal at point A:

Signal at point B:

Signal at point C:

Signal at point D:

The baseband I and Q signals of the receiving end are obtained on the basis of the signal at point D as described below.

,

,

The ratio of the I and Q signals and? _M using the ratio are obtained as follows.

The magnitude (K _m ) and the phase change (? _M ) generated by each transmission / reception path can be obtained using the above equation. Therefore, by using the above analysis, it is possible to derive the relative size and phase difference with respect to the transmission / reception path of the channel measurement system corresponding to each of the multiple antennas.

In the path correction step S400, when the actual radio channel measurement system is operated using the relative size and phase difference derived in the signal analysis step S300, the transmission part of the baseband module measures the size and phase of the transmission signal according to the measured path, And the reception unit relatively reflects the magnitude and phase of the received signal for each measured path.

Alternatively, the relative size and phase difference may be reflected in the process of post-processing the measured data without reflecting it in operation of the actual measurement system.

FIG. 3 illustrates an embodiment of applying a transmission / reception path correction method in a multi-antenna wireless channel measurement system of the present invention using a loop back path.

In the single path forming step S100, a loopback path and a measurement module for signal measurement are arranged.

Referring to FIG. 3, the loopback path includes a first loopback path for transmitting signals distributed to the transmission antenna elements back to a reception path, and a first loopback path for distributing a single path signal of the transmission end to multiple paths, To the second loopback path.

The first loopback path may include a plurality of directional couplers 207 to 210, an N-path coupler 211, a switch 212, and a directional coupler 220.

The plurality of directional couplers 207 to 210 serve to extract a signal to be distributed to each antenna array element.

The N-path combiner 211 plays a role of composing signals extracted from the plurality of directional couplers 207 to 210 into a single path.

The switch 212 transmits the transmission signal composed of the single path to the receiving end. A switch 212 is used to prevent a transmit signal from entering the receive when the measurement system is operating at a time outside the transmit correction time. Also, a non-reflective switch can be used to prevent the switch 212 from affecting the transmission path in the OFF state.

The directional coupler 220 transmits a transmission signal having passed through the switch to the receiving end.

The second loopback path may include a directional coupler 205, a switch 213, an N-path distributor 214, and a plurality of directional couplers 215 to 218.

The directional coupler 205 plays a role of extracting a transmission signal of a single path.

The switch 213 transmits the transmission signal composed of the single path to the receiving end. A switch 213 is used to prevent the transmission signal from entering the reception when the measurement system is operating at a time outside the reception correction time. In addition, a non-reflective switch can be used to prevent the switch 213 from affecting the transmission path when the switch 213 is turned off.

The N-path splitter 214 distributes the extracted transmission signal to a plurality of antenna array elements.

A plurality of directional couplers 215 to 218 transmit the distributed transmission signals to each antenna array element.

After the loop back path is disposed as described above, the measurement module is disposed at the input end and the output end.

The signal measuring step (S200) to the path correcting step (S400) are the same as in the description of FIG.

However, the size and phase changes caused by using directional couplers, N-path distributors, and N-path couplers can be measured in advance for each individual device and reflected in the signal analysis step or the path correction step.

FIG. 4 illustrates an embodiment of applying a transmission / reception path correction method in the multi-antenna wireless channel measurement system of the present invention using an attenuator.

If it is not easy to construct a loopback path inside the radio channel measurement system, path correction can be performed by adding only the power combiner 312, the power divider 313 and the attenuator 313 as shown in FIG. 4 have.

In the single path forming step S100, a power combiner 312, a power divider 313, an attenuator 314, and a measurement module for signal measurement are disposed.

The attenuator 314 is added to prevent a large power transmission signal from being input to the reception signal because a plurality of transmission / reception paths are converted into a single path when the power combiner 312 and the power splitter 313 are used. Therefore, the degree of attenuation of the signal generated by the attenuator 314 can be determined in consideration of the output power of the transmitting end and the allowable power range of the receiving end.

As described above, the attenuator 314 disposes the power combiner 312 and the power divider 313, and then places the measurement module at the input and output stages.

In the signal measurement step S200, the transmission and reception signals are measured by switching the switches of the transmitting and receiving ends. In order to convert a plurality of transmission paths and reception paths into a single path without interfering with each other by setting to select only a desired path through switches 305 and 306 in each transmission / reception path correction.

The signal analysis step S300 and the path correction step S400 are the same as those in the description of FIG.

However, the magnitude and phase changes caused by the power combiner 312, the power divider 313, and the attenuator 314 may be measured in advance for each individual device and reflected in the signal analysis step or the path correction step

FIG. 5 is a diagram illustrating a method of compensating transmission / reception paths in a multi-antenna wireless channel measurement system according to an embodiment of the present invention when an isotropic antenna is used.

The isotropic antenna refers to a case where each antenna element of the multiple array antenna is circularly arranged. These circular array antennas are frequently used in the measurement of the start angle and the arrival angle.

The single path forming step S100, the signal analyzing step S300, and the path correcting step S400 are the same as in the description of FIG.

In the signal measurement step, the transmission signal is transmitted while the switch of the transmission power splitter 405 is switched, and the radiated signal is fixed to the reception power combiner 406 so as to receive the signal through the antenna R positioned at the center of the circular array antenna . The transmission and reception signals are measured for the path corresponding to the antenna element of each circular array antenna.

FIG. 6 is another embodiment in which the transmission path correction method in the multi-antenna wireless channel measurement system of the present invention is applied to the case of using an isotropic antenna.

The single path forming step S100, the signal analyzing step S300, and the path correcting step S400 are the same as in the description of FIG.

In the signal measurement step, the transmission signal is fixed by the switch of the transmission power splitter 405 to be radiated only through the antenna T positioned at the center of the circular array antenna, and the reception signal is received while the switch of the reception power combiner 406 is switched . The transmission and reception signals are measured for the path corresponding to the antenna element of each circular array antenna.

The present invention is not limited by the above-described embodiments and the accompanying drawings, but is intended to be limited only by the appended claims. It will be apparent to those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. something to do.

1 is a flowchart of a transmission / reception path correction method in a multi-antenna wireless channel measurement system according to the present invention.

FIG. 2 illustrates an embodiment of applying a transmission / reception path correction method in a multi-antenna wireless channel measurement system of the present invention.

3 illustrates an embodiment of applying a transmission / reception path correction method in a multi-antenna wireless channel measurement system of the present invention using a loop back path.

FIG. 4 illustrates an embodiment of applying the transmission path correction method in the multi-antenna wireless channel measurement system of the present invention using an attenuator.

5 and 6 illustrate an embodiment in which the transmission path correction method in the multi-antenna wireless channel measurement system of the present invention is applied to the case of using an isotropic antenna.

Claims (10)

A single path forming step of connecting a front end or a rear end of a transmitting end of the multi-antenna radio channel measuring system to a front end or a rear end of a receiving end forming a single path; Measuring a baseband transmission / reception signal for a path corresponding to each antenna element by switching and operating a path to an antenna element of the multiple antennas by using the single path formed multi-antenna radio channel measurement system; A signal analysis step of analyzing the measured transmission / reception signals to derive a magnitude and a phase change caused by a transmission / reception path; And And correcting a transmission / reception path of the radio channel measurement system using the derived size and phase value. 2. The method of claim 1, wherein the single pass forming step comprises: And connecting the rear end of the transmitting end and the rear end of the receiving end through an array antenna to form the single path. 2. The method of claim 1, wherein the single pass forming step comprises: And connecting a front end or a rear end of the transmitting end and a front end or a rear end of the receiving end using a loopback circuit to form the single path. 4. The circuit of claim 3, wherein the loopback circuit A first loopback path for transmitting signals distributed to the transmission antenna elements into a single path and then transmitting the signals to a reception path, and a second loopback circuit for distributing the single path signal of the transmitting end to a path of a receiving path A method for calibrating transmission and reception paths in a multi-antenna wireless channel measurement system. 5. The method of claim 4, The first loopback path A plurality of directional couplers for extracting a signal to be distributed for each antenna array element; And And an N-path combiner configured to combine the signals extracted from the plurality of directional couplers into the single path, The second loopback path A directional coupler for extracting the transmission signal of the single path; And And a K-path splitter for distributing the extracted transmission signal to a plurality of antenna array elements. 2. The method of claim 1, wherein the single pass forming step comprises: Receiving path correction method in a multi-antenna radio channel measurement system using a power combiner and a power divider to convert a plurality of transmission / reception paths into the single path, and using an attenuator to attenuate the output power of the transmission terminal to the power of the receiving end . 2. The method of claim 1, And measuring the transmission / reception signal by fixing a switch of the reception power combiner so as to radiate a transmission signal while switching the switch of the transmission power splitter and to receive the radiated signal through an antenna located at the center of the circular array antenna, A method for correcting transmission / reception paths in a system. 8. The method of claim 7, wherein the signal measurement step And measuring the transmission / reception signal for a path corresponding to each antenna element of the circular array antenna. 2. The method of claim 1, Receiving a signal transmitted from a power splitter through a plurality of antennas; measuring a transmission / reception signal of the transmission power divider; A method for correcting transmission / reception paths in a system. 10. The method of claim 9, And measuring the transmission / reception signal for a path corresponding to each antenna element of the circular array antenna.

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