KR100554507B1 - Phase Error Control System for Receiver of Smart Antenna System - Google Patents

Abstract

1. TECHNICAL FIELD OF THE INVENTION

The present invention relates to a phase error control apparatus and method applied to an RF receiver of a smart antenna system.

2. The technical problem to be solved by the invention

The present invention provides a phase error control device for controlling the smart antenna system to accurately form the beam without requiring a high precision manufacturing work to phase correction in the RF receiver of the smart antenna system and its The purpose is to provide a method.

3. Summary of Solution to Invention

The present invention provides a pilot signal providing means for providing a reference signal for detecting a phase of each main RF received signal received through a plurality of antenna elements in a radio frequency (RF) receiver phase error control apparatus of a smart antenna system. ; A plurality of first coupling means for adding a pilot signal received from the pilot signal providing means to each main RF received signal; Signal processing means for down-converting and processing each received signal received from the first coupling means; A plurality of second coupling means for extracting phase information from each output signal provided from the signal processing means; Comparing the reference pilot signal phase provided from the pilot signal providing means with the main RF signal phase on each RF received signal path input from the second coupling means to detect the changed phase, and accordingly the signal processing means Control means for controlling the; And filtering means for removing the pilot signal from the received signal on each signal path signal-processed by the signal processing means.

4. Important uses of the invention

The present invention is used for smart antenna system and the like.

Smart Antenna, RF, Phase Error Correction, Pilot Signal

Description

Phase error control device applied to RF receiver of smart antenna system {Phase Error Control System for Receiver of Smart Antenna System}             

1 is a schematic configuration diagram for explaining a technical concept of a smart antenna system to which the present invention is applied.

2 is a conceptual diagram illustrating a beamforming method using a phased array antenna in a smart antenna system to which the present invention is applied.

Figure 3 is a configuration diagram of an RF receiver phase error control device according to an embodiment of the present invention.

4 is a diagram illustrating an embodiment of the phase error controller of FIG. 3.

FIG. 5 is a diagram illustrating an embodiment of the signal processor of FIG. 3. FIG.

6 is an exemplary view illustrating an RF receiver configured using a phase error control apparatus according to the present invention.

* Explanation of symbols for the main parts of the drawings

11A to 11N: first coupler 12A to 12N: signal processor

13A-13N: 2nd coupler 14A-14N: Filter

41: analog-to-digital converter 42: processor

43A to 43N: Digital to Analog Converter 121: Frequency Down Converter

122: amplifier 123: bandpass filter

124: phase shifter 125: attenuator

151 switch 161 pilot signal generator

152: phase detector 162: divider

153: phase error controller 163: pilot signal transmitter

The present invention relates to an RF receiver of a smart antenna system, and more particularly, to an apparatus and method for controlling a phase error applied to the RF receiver in a smart antenna system.

In the smart antenna system, in order to correct phase and magnitude errors for each RF path, different transfer functions should be estimated for each RF path, and the difference in transfer functions between the RF paths should be corrected. This is called RF error correction. The transfer function error can be corrected in the analog domain or in the digital domain.

The correction method in the digital domain is a method of inputting an error correction signal generated inside the system to an input terminal behind the receiving antenna and analyzing it at the digital baseband, which is advantageous in that it provides a more accurate correction of the magnitude error. There was a difficulty in correcting both phase and phase error.

Therefore, in the conventional smart antenna system, only the size error correction of the digital correction method is performed, and the phase error has been used to correct the phase error using a manufacturing technique requiring high precision. However, even if the phase error correction method is precisely adjusted in the initial stage, errors such as fluctuations in phase characteristics that may occur when the operating region of the active element in the receiver enters the nonlinear region cannot be corrected. there was.

The present invention has been proposed to solve the above problems, and in order to achieve accurate beam formation in a smart antenna system without requiring a high precision work for the phase correction in the analog portion of the smart antenna system An object of the present invention is to provide a phase error control device and a method thereof.

The phase error device of the present invention for achieving the above object, in the phase error control device of the RF (Radio Frequency) receiver of the smart antenna system, detecting the phase of each main RF received signal received through a plurality of antenna elements Pilot signal providing means for providing a reference signal for; A plurality of first coupling means for adding a pilot signal received from the pilot signal providing means to each main RF received signal; Signal processing means for down-converting and processing each received signal received from the first coupling means; A plurality of second coupling means for extracting phase information from each output signal provided from the signal processing means; Comparing the reference pilot signal phase provided from the pilot signal providing means with the main RF signal phase on each RF receiving signal path input from the second coupling means to detect the changed phase, and accordingly the signal processing means Control means for controlling; And filtering means for removing the pilot signal from the received signal on each signal path signal-processed by the signal processing means.

The above objects, features and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In general, the performance and channel capacity of a CDMA mobile communication system are fundamentally determined by the characteristics of radio propagation channels such as co-channel interference signals, path loss, multipath fading, signal delay, Doppler spread, and shadowing. Limited to. In other words, the channel capacity is reduced by the interference signal due to the large number of users present in the cell and the propagation channel characteristics between the terminal and the base station. Therefore, a technique for overcoming such performance degradation is required. The smart antenna system is a technology that can effectively improve performance and channel capacity against performance degradation caused by interference signals and radio channel characteristics caused by other users.

1 is a schematic configuration diagram illustrating a technical concept of a smart antenna system to which the present invention is applied.

As shown in FIG. 1, the smart antenna system generates a beam pattern such that an antenna gain is large for a desired user by using an array antenna having a plurality of antenna elements, and an antenna gain for an interfering user (interfering signal source). It is a technique of increasing the channel capacity by forming a beam pattern to minimize this.

2 is a conceptual view illustrating a beamforming method using a phased array antenna in a smart antenna system to which the present invention is applied.

의 방향

를 알기 위해서는 위상 배열 안테나를 사용하며, 안테나 엘리먼트간 간격 d 로 인해 생기는 각 엘리먼트 수신 신호들간의 위상 차와 각 경로간 가중치를 이용해 입사 방향을 알아내게 된다. 그리고, 이와같은 방식으로 통화 신호원의 입사 방향을 알아내야 도 1 에서와 같은 빔 패턴 형성이 가능해진다.As shown in Fig. 2, the incident signal

Direction of

In order to know, phase array antenna is used, and the direction of incidence is determined by using the phase difference between each element received signals due to the distance d between antenna elements and the weight of each path. In this way, it is possible to form the beam pattern as shown in FIG. 1 by finding the incident direction of the call signal source.

In the smart antenna system to which the present invention is applied, the RF (Radio Frequency) receiver phase error control device operates on a principle of extracting phase information by adding a pilot signal to each received RF signal on the receiver path. That is, the phase error control apparatus of the RF receiver applies pilot signals to N paths of the main radio frequency signals received from the N antenna elements, and then frequency downconverts the RF or IF (Intermediate Frequency). Phase information is extracted from the signal through a phase detector, and the phase error controller uses the extracted phase information to control a phase shifter (see 124 of FIG. 4) in a signal processor located on each of the N RF signal paths. You get

3 is a structural diagram of an embodiment of an RF receiver phase error control apparatus according to the present invention.

As shown in FIG. 3, RF signal paths exist for each of the N antenna elements. The pilot signal generator 161 generates a pilot signal, which is a continuous wave (CW) signal spaced several MHz from the received main RF signal, and the generated pilot signal is used as a reference signal for detecting a phase of the main RF received signal. do.

The pilot signal output from the pilot signal generator 161 is input to the splitter 162 and the pilot signal transmitter 163. The pilot signals input to the divider 162 are divided into N and input to the first couplers 11A to 11N existing in each RF path. The first couplers 11A to 11N are coupled to each other to add a pilot signal applied from the pilot signal generator 161 to a main RF received signal on a corresponding path.

Meanwhile, the pilot signal transmitter 163 down-converts the received pilot signal in frequency, and the frequency down-converted pilot signal is input to the phase detector 152. The signal processors 12A to 12N present in each RF path function to perform frequency downconversion, amplification, bandpass filtering, phase shift, and attenuation of the coupled RF signal, and each output signal is provided in each RF path. Input to existing second couplers 13A to 13N. In addition, the switch 151 switches only a signal of a specific path among the output signals of the plurality of second couplers 13A to 13N existing in each RF signal path to be input to the phase detector 152.

The phase detector 152 compares the phase of the reference pilot signal received from the pilot signal transmitter 163 with the phase of the main RF signal after passing through the second couplers 13A to 13N present in each RF path. Detect the phase. The phase error controller 153 receives the phase information detected in the N RF signal paths from the phase detector 152 and uses the phase converter 124 existing in the signal processors 12A to 12N of each RF path. To control.

The second couplers 13A to 13N present in each RF path extract frequency downconverted main RF signals and pilot signals through signal processors 12A to 12N of each RF path, and then input terminals of the switch 151. It extracts the signal through the second couplers 13A to 13N present in each RF path, and the phase error is changed through the phase detector 152 while the pilot signal passes through the receiver. This is for input to the controller 153. The bandpass filters 14A-14N present in each RF path serve to cancel the pilot signal coupled to the main RF signal. That is, the pilot signal used for the phase error correction may act as a kind of interference signal, so it must be removed after the phase error correction. Therefore, the bandpass filters 14A to 14N, which can pass only the main RF received signal band, are used to eliminate the pilot signal.

4 is a configuration diagram of an embodiment of the phase error controller 153 according to the present invention.

As shown in Fig. 4, the controller is composed of an analog / digital converter 41, a processor 42, and digital / analog converters 43A to 43N. The analog / digital converter 41 is a device for converting an analog output signal of a phase detector into a digital signal. In addition, the processor 42 sets input information of the digital / analog converters 43A to 43N according to the information applied from the analog / digital converter 41, and generates a control signal for controlling the switch 151. Let's do it. Meanwhile, the digital / analog converters 43A to 43N convert the digital phase calibration information received from the processor 42 into an analog voltage.

Accordingly, the phase error controller 153 controls the N RF signals to have the same phase difference through the phase information of the RF signals for the N paths detected from the phase detector 152, and the signals existing on the respective RF paths. Independent phase correction information is provided to the phase converter 124 in the processors 12A to 12N.

FIG. 5 is a diagram illustrating an example of configuring an RF receiver by using the phase error controller of the present invention as described above. As shown in FIG. It is possible to maintain coherence characteristics between the paths and to have the same phase noise.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes are possible in the art without departing from the technical spirit of the present invention. It will be clear to those of ordinary knowledge.

 As described above, the present invention has the effect of enabling accurate beam formation without precisely manufacturing the receiver in order to minimize the phase error of the RF receiver of the smart antenna.

On the other hand, there is another effect of maintaining the phase characteristics of each receiver to be the same without using expensive components designed to operate only in the linear region, the phase error generated by the active elements in the non-linear region.

Claims (5)

In the RF (Radio Frequency) receiver phase error control device of the smart antenna system, Pilot signal providing means for providing a pilot signal; A plurality of first coupling means for adding a pilot signal received from the pilot signal providing means to each main RF received signal received through a plurality of antenna elements; Signal processing means for down-converting and processing each received signal received from the first coupling means; A plurality of second coupling means for extracting phase information from each output signal provided from the signal processing means; And Comparing the reference pilot signal phase provided from the pilot signal providing means with the main RF signal phase on each RF receiving signal path input from the second coupling means to detect the changed phase, and accordingly the signal processing means Control means for controlling; And Filter means for removing a pilot signal from a received signal on each signal path signal-processed by said signal processing means, The signal processing means is an RF receiver phase error control apparatus of a smart antenna system for analog-phase shifting the input signal under the control of the control means. The method of claim 1, The pilot signal providing means, Pilot signal generating means for generating the pilot signal; Pilot signal transmission means for frequency downconverting the pilot signal received from the pilot signal generation means and providing the pilot signal to the control means; And Distribution means for distributing the pilot signal received from the pilot signal generating means to the plurality of first coupling means RF receiver phase error control device of a smart antenna system comprising a. The method of claim 1, The control means, Switching means for selecting only a signal input from a specific coupling means among signals received from the plurality of second coupling means; Phase error detection means for comparing the phase of the signal input from the switching means with the signal input from the pilot signal providing means and detecting the difference; And The phase error control means for receiving the signal from the phase error detection means and controlling the switching means and the signal processing means; RF receiver phase error control device of a smart antenna system comprising a. The method of claim 3, wherein The phase error control means, A first converter converting the analog signal received from the phase detector into a digital signal; A processor unit for receiving a digital signal from the first converter to generate a digital phase error correction signal, to control the switching means, and to generate the digital phase correction signal; And A plurality of second converters for converting the digital signal received from the processor unit into an analog signal for input to the signal processing means on each RF receiving signal path RF receiver phase error control device of a smart antenna system comprising a. The method of claim 1, The signal processing means, Frequency downconverting means for downconverting the frequency of the signal input from the first coupling means; Amplifying means for amplifying a signal input from said frequency downconverting means; Bandpass filtering means for bandpassing the signal input from said amplifying means; Phase shifting means for shifting a phase of a signal input from the filtering means in accordance with control of the control means; And RF receiver phase error control apparatus of the smart antenna system including attenuating means for attenuating the magnitude of the signal received from the phase shifting means.

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