KR20070060818A - Rf signal coupling and dividing device for error correction, transmitting/receiving apparatus of smart antenna system using the device - Google Patents

Abstract

An RF signal coupling and dividing apparatus and a transmitting/receiving apparatus of a smart antenna system using the same are provided to perform accurate error correction by separating a transmission error correction path and a reception error correction path for correcting errors of a transmission/reception signal. An RF transmitting/receiving unit(20) processes a reception signal provided from an array antenna(10) into a baseband signal and outputs it, and processes an applied transmission baseband signal into a transmission signal and provides it to the array antenna(10). A baseband signal processing unit(30) receives the reception baseband signal and processes it, provides the transmission baseband signal to the RF transmitting/receiving unit(20), and controls the transmission baseband signal according to an applied transmission error correction signal. An error correcting unit(50) performs error correction on the transmission and reception signals, and outputs a corresponding reception error correction signal and transmission error correction signal. A signal coupling and dividing unit(40) couples the transmission signal outputted from the RF transmitting/receiving unit(20) and outputs it to the error correcting unit(50) through a transmission error correction path, and injects the reception error correction signal provided from the error correcting unit(50) to the reception signal through a reception error correction path.

Description

RF signal coupling and dividing device for error correction, transmitting / receiving apparatus of smart antenna system using the device

1 is a structural diagram of a transmission and reception apparatus of a smart antenna system according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating the structure of the signal coupling and divider unit shown in FIG. 1 in detail.

The present invention relates to a smart antenna system, and more particularly, in a smart antenna system for a base station using a time division duplex (TDD) method, an RF signal coupling and dividing device for error correction, and transmission and reception using the same Relates to a device.

In the mobile communication field, a number of new technologies are being actively researched in recent years to adjust the beam pattern of the antenna to suppress interference and noise, thereby simultaneously increasing the capacity and reliability of the communication system. The so-called smart antenna technology is emerging as the core technology of the next generation mobile communication system.

Smart antenna technology generates a beam pattern to increase antenna gain for a given user when there are multiple user signals in the same band, and forms a beam pattern to minimize antenna gain for an interfering user so that each user is independent of each other. It is a spatial filtering technique that reduces interference between users by forming an antenna beam.

Beamforming in a smart antenna system is implemented using analog devices in the RF band or digitally after converting the RF signal to baseband. Among them, the digital beamforming method is more used than the analog method because it can make a more free beam pattern and is easy to implement.

In the digital beamforming method, the RF signal received by each array antenna is down-converted to digital by using an independent receiver, and then converted to digital. The beamforming is performed by changing its size and phase. Therefore, in order to accurately control the direction in the baseband, the relative magnitude and phase of each channel of the RF signal in the array antenna stage must be maintained as the baseband. However, in actual systems, because the channel has different magnitudes and phase characteristics due to analog device characteristics and various other reasons, it is necessary to periodically measure and eliminate them. This is called RF error correction.

In the conventional smart antenna system, for the RF error correction, by using the coupling and dividing device of the RF signal including the bidirectional coupler, the transmission signal transmitted to the antenna to provide the error correction device, or is provided from the error correction device The correction signal was coupled to the signal output from the antenna.

However, since the signal path for error correction between the coupling and dividing device of the conventional RF signal and the error correction device is connected to the semiconductor switch, a large number of signals are transmitted and received through the path depending on the physical characteristics and properties of the semiconductor. Distortion may occur. Accordingly, a mechanically stable mechanical switch is used, but in this case, the switching timing is slow and the price is increased.

To compensate for this, instead of a semiconductor or mechanical switch, a method of isolating two transmission / reception ports using a circulator has been used. However, even in this case, due to the low separation rate (typically 15-20dB), the signals coupled in the bidirectional coupler are mixed with each other. As a result, a problem such as input of a distorted signal to the error correction device occurs, and an error correction coefficient for RF correction is not accurately calculated, and as a result, accurate transmission / reception signals are not formed.

Therefore, the technical problem to be achieved by the present invention is to solve such a problem, and to increase the mutual signal separation rate of the RF coupling and dividing device for error correction of the transmission and reception signals in the smart antenna system.

Another object of the present invention is to provide a transceiver of a smart antenna system capable of performing accurate error correction using such an RF coupling and dividing device.

In accordance with an aspect of the present invention for achieving the above technical problem, a transmission and reception apparatus of a smart antenna system includes a plurality of array antennas, the transmission and reception apparatus of a smart antenna system for performing error correction for the signal transmitted and received through the antenna An RF transceiver configured to process and output a received signal provided from the array antenna as a baseband signal for reception, and process the applied baseband signal as a transmission signal and provide the received baseband signal to the array antenna; A baseband for receiving and processing a baseband signal provided from the RF transceiver, providing the baseband signal for transmission to the RF transceiver, and adjusting the baseband signal according to an applied transmission error correction signal; A signal processor; An error correction unit for performing error correction on the transmission signal and the reception signal and outputting a reception error correction signal and a transmission error correction signal corresponding thereto; And coupling a transmission signal output from the RF transceiver to an error correction unit through a transmission error correction path, and receiving a reception error correction signal provided from the error correction unit to the reception signal through a reception error correction path. And a signal coupling and dividing portion to be injected. In particular, the signal coupling and dividing unit outputs the signal output from the RF transceiver and flowing into the transmission error correction path and the signal flowing into the reception error correction path, respectively.

In addition, the RF signal coupling and dividing apparatus according to an aspect of the present invention, RF signal coupling and dividing apparatus connected to a plurality of array antenna, RF transceiver and error correction device, performing a signal processing for error correction A plurality of bidirectional couplers positioned between the array antenna and the RF transceiver and injecting reception error correction signals applied from the error correction apparatus into the reception signals, respectively, and coupling and outputting the transmission signals; A circulator connected to the error correction device to generate a reception error correction path and a transmission error correction path; A divider for supplying a reception error correction signal applied through the reception error correction path to a corresponding bidirectional coupler; A switch configured to output a transmission signal coupled and output from each bidirectional coupler to the transmission error correction path; And an isolator separating the transmission signal input to the divider and the transmission signal input to the switch through the bidirectional coupler.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention. Like parts are designated by like reference numerals throughout the specification.

In addition, when a part is said to "include" a certain component, this means that it may further include other components, except to exclude other components unless otherwise stated.

1 is a structural diagram of a transmission and reception apparatus of a smart antenna system according to an embodiment of the present invention.

Smart antenna system according to an embodiment of the present invention is the array antenna 10, the RF transceiver 20, the baseband signal processor 30, the signal coupling and divider 40, the error correction unit 50 and the error And a correction signal converter 60.

The array antenna 10 is composed of a plurality of antennas to generate a desired antenna beam pattern.

The RF transceiver 20 includes a transceiver equal to the number of array antennas, and converts a signal from the baseband signal processor 30 into an RF signal to provide each array antenna, or each The RF signal from the array antenna is converted into a baseband signal and output to the baseband signal processor 30.

The signal coupling and dividing unit 40 couples the transmission signal output from the RF transceiver 20 to the error correction unit 50 or receives the signal provided from the error correction unit 50 from the array antenna. And injects the received signal into the RF transceiver 20.

The error correction unit 50 corrects a reception transfer function error included in an RF signal received by each array antenna, or corrects a transmission transfer function error for each antenna, and outputs an error correction signal corresponding thereto. Specifically, the phase of the signal input from the error correction signal converter and the phase of the signal transmitted to the baseband signal processor 30 are compared to calculate an error correction coefficient for the transmission transfer function, and corresponding transmission error correction The signal is provided to the baseband signal processor 30. In addition, the phase of the signal input from the baseband signal processor 30 and the signal output to the error correction signal converter 60 are compared to calculate an error correction coefficient for the reception transfer function, and output a reception error correction signal.

The error correction signal converter 60 down-converts the transmission signal provided from the signal coupling and dividing unit 40 or outputs the error correction signal up-converting to the signal coupling and dividing unit 40. do. For convenience, it may also be called a signal converter.

In the transmission and reception apparatus of the smart antenna system having such a structure, the signal coupling and dividing unit 40 has the following structure in order to increase the signal separation rate.

2 is a detailed structural diagram of a signal coupling and dividing unit according to an exemplary embodiment of the present invention.

As shown in FIG. 2, the signal coupling and divider unit 40 according to an exemplary embodiment of the present invention includes a plurality of bidirectional couplers 41 positioned between the array antenna 10 and the RF transceiver unit 20. , Divider 42, switch 43, circulator 44, and isolator 45.

The circulator 44 forms a signal path for error correction between the signal coupling and dividing unit and the error correction unit. That is, a reception error correction path and a transmission error correction path are respectively formed.

The divider 42 supplies a reception error correction signal input through the circulator 44 to each bidirectional coupler 41, and the switch 43 receives the received signal provided from each bidirectional coupler circulator 44. By supplying to the error correction unit 50 to be provided.

The bidirectional coupler 41 couples and outputs a transmission signal provided from the RF transceiver to the array antenna, or couples a reception error correction signal applied to the reception signal provided from the array antenna to the RF transceiver.

The isolator 45 is positioned between the circulator 44 and the divider 42 to block a signal flowing into the circulator 44 through the divider 42.

The operation of the isolator 45 will be described in more detail. To correct the error of the transmission signal, the transmission signal input to the RF transceiver is coupled by the bidirectional coupler 41 and provided to the circulator 44 through the switch 43. At this time, the transmission signal coupled to the divider 42 is input due to the characteristics of the bidirectional coupler, and the signal is attenuated by the dividing loss of the divider and is also input to the circulator 44. Therefore, in addition to the transmission signal from the switch 43, an unwanted signal from the divider 42 is separated by an isolation (e.g., 15 to 20 dB) of the circulator 44 and input to the error correction signal conversion unit 60, and finally, Is input to the error correction unit 50. Therefore, when viewed from the error correction signal converter 60, the difference between the magnitude of the signal required for the transmission signal correction and the unwanted signal is only 15 ~ 20dB.

 As a result, only the signal output through the switch 43 should be input to the signal converter 60, but due to the low separation rate of the circulator 44, a signal having a different phase (a signal introduced from the divider) is additionally inputted. In this case, an effect of summation of the signals occurs. This causes the phase of the down-converted signal input to the error correction unit 50 to be different, and as a result, the error correction unit 50 cannot calculate an accurate error correction coefficient for the transmission signal correction.

Accordingly, in the embodiment of the present invention, the isolator 45 is positioned between the circulator 44 and the divider 42 to increase the separation rate between the signal required for the transmission signal correction and the signal that is not required, so that the signals The error correction signal converter 60 does not add up. In this case, the isolator 45 used may have a characteristic with a separation rate of about 25-30 dB. In addition, a circulator terminated with 50 ohms or the like may be used as the isolator.

Therefore, the separation rate between the signal required for the transmission signal correction and the signal not required by the isolator 45 and the circulator 44 is improved to 40-50 dB, for example, so that a sufficient S / N value for error correction can be obtained. It can be secured.

Next, an error correction operation of the smart antenna system according to the embodiment of the present invention will be described based on the structure.

When the system is initially powered on, the error correction unit 50 first generates a reception error correction signal. The reception error correction signal is up-converted through the error correction signal converter 60, and then the reception error correction path. That is, injection is performed to the received signal input from the array antenna 10 to the RF transceiver 20 through the circulator 44, the isolator 45, and the divider 42 of the signal coupling and divider 40. do. In this case, the power of the reception error correction signal may be included within the reception signal input range of the RF transceiver 20.

Thereafter, the error correction unit 50 compares the phase (or CSR) of the received signal input from the baseband signal processing unit 30 to the signal output to the error correction signal converter 60. By comparing the noise ratio) and the difference between the reference value, etc., transfer function estimation is performed and an error correction coefficient is calculated based on the result. The received error correction signal corresponding to the error correction coefficient is output to the error correction signal converter 60 to perform error correction on the received signal output from the array antenna.

Meanwhile, the transmission signal generated from the baseband signal processor 30 and transmitted to the array antenna 10 through the RF transceiver 20 is coupled by the bidirectional coupler 41 to transmit a transmission error correction path, that is, the switch 43. ) And the circulator 44 are input to the error correction signal converter 60 to be processed downward. At this time, even if a transmitted signal coupled according to the characteristic of the bidirectional coupler is input to the divider 42, the transmitted signal output from the divider 42 is firstly spaced apart by the isolator 45, and the circulator 44 By being spaced apart by the second, the error correction signal converter 60 generates a large phase difference between the input signals and does not add to each other.

Accordingly, the error correction unit 50 estimates the transmission signal transfer function based on the signal input only through the transmission signal error correction path formed only through the circulator 44 and the switch 43, and accordingly, the error correction coefficient for the transmission signal. To calculate. The transmission error correction signal corresponding to the error correction coefficient is output to the baseband signal processor 30 to perform error correction on the transmission signal.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

As described above, according to an embodiment of the present invention, the circulator does not use a switch or a single circulator as a means for separating two paths in an RF coupling and dividing apparatus used for transmitting and receiving a wireless system. By using in parallel with isolator, not only stable operation can be expected during operation, but also the separation rate of signals input to each path can be significantly increased.

In addition, when the device is applied to a smart antenna system, accurate error correction may be performed by separating a transmission error correction path and a reception error correction path for error correction of a transmission / reception signal.

In addition, by using a passive element having stable characteristics without using a semiconductor element such as a switch, the system can be stably operated by separating signals inputted in each path.

Claims (5)

In the transceiver of the smart antenna system including a plurality of array antenna, performing the error correction for the signal transmitted and received through the antenna, An RF transceiver configured to process and output a received signal provided from the array antenna as a baseband signal for reception, and process the applied baseband signal as a transmission signal and provide the received baseband signal to the array antenna; A baseband for receiving and processing a baseband signal provided from the RF transceiver, providing the baseband signal for transmission to the RF transceiver, and adjusting the baseband signal according to an applied transmission error correction signal; A signal processor; An error correction unit for performing error correction on the transmission signal and the reception signal and outputting a reception error correction signal and a transmission error correction signal corresponding thereto; And Coupling a transmission signal output from the RF transceiver and outputs the error correction unit through a transmission error correction path, and injects a reception error correction signal provided from the error correction unit to the received signal through a reception error correction path. Signal coupling and divider Including; The signal coupling and divider unit And an isolator output from the RF transceiver and separated from each other into a signal introduced into the transmission error correction path and a signal introduced into the reception error correction path. The method of claim 1 The signal coupling and divider unit A plurality of bidirectional couplers positioned between the array antenna and the RF transceiver and injecting received reception error correction signals into the received signals, respectively, and coupling and outputting the transmitted signals; A circulator for generating the reception error correction path and the transmission error correction path, respectively; A switch configured to output a transmission signal coupled and output from the bidirectional coupler to the transmission error correction path; And A divider which outputs a reception error correction signal applied through the reception error correction path to the bidirectional coupler. Including, The isolator is located between the circulator and the divider, the transmission and reception of the smart antenna system spaced apart from the transmission signal input from the bidirectional coupler to the transmission error correction path from the bidirectional coupler Device. The method according to claim 1 or 2 Down converting the signal output from the signal coupling and dividing unit provided to the error correction unit, and further converts the signal output from the error correction unit to provide the signal coupling and dividing unit further includes a signal converter Transmitting and receiving device of the smart antenna system. In an RF signal coupling and dividing device connected to a plurality of array antennas, an RF transceiver and an error correction device to perform signal processing for error correction, Located between the array antenna and the RF transmitting and receiving device, injecting the received error correction signal applied from the error correction device to the received signal, respectively, and outputs by coupling the transmission signal output from the RF transmitting device to the array antenna Multiple bidirectional couplers; A circulator connected to the error correction device to generate a reception error correction path and a transmission error correction path; A divider for supplying a reception error correction signal applied through the reception error correction path to a corresponding bidirectional coupler; A switch configured to output a transmission signal coupled and output from each bidirectional coupler to the transmission error correction path; And An isolator separates the transmission signal input to the divider and the transmission signal input to the switch through the bidirectional coupler. RF signal coupling and dividing apparatus comprising a. The method of claim 4 And the isolator is located between the circulator and the divider.

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