KR100588974B1 - Apparatus and method for linearization using predistortion in wireless communication terminal - Google Patents

Abstract

1. TECHNICAL FIELD OF THE INVENTION

The present invention relates to a predistortion linearization device and a method thereof in a wireless communication terminal.

2. The technical problem to be solved by the invention

The present invention uses a digital signal processor (DSP) embedded in a modem chip of a wireless communication terminal for power control and linearization of a transmitting end, extracts a part of the main signal of the transmitting end, and inverts the main signal of the transmitting end by predistorting the main signal of the transmitting end. Accordingly, an object of the present invention is to provide a predistortion linearization device and a method thereof in a wireless communication terminal capable of compensating for nonlinear characteristics of a wireless communication terminal transmitting end.

3. Summary of Solution to Invention

The present invention comprises: feedback means for generating and returning a signal having a phase difference of 180 degrees with a main signal input to a power amplifier; A first coupler for coupling a signal fed back from the feedback means to a signal divided from the main signal; A first amplifier for amplifying the signal coupled through the first coupler; And a second coupler extracting a part of the main signal inputted to the power amplifier and outputting the partial signal to the feedback means, and combining the signal amplified by the first amplifier with the main signal inputted to the power amplifier to remove the intermodulation component. Including.

4. Important uses of the invention

The present invention is used for the linearization of the wireless communication terminal.

Wireless communication terminal, predistortion, linearization, attenuator, delayer, phase shifter, DSP

Description

Predistortion linearization device and method in wireless communication terminal {Apparatus and Method for Linearization using Predistortion in Wireless Communication Terminal}             

1 is a configuration diagram of an embodiment of applying a predistortion linearization apparatus according to the present invention to a transmitting terminal of a wireless communication terminal;

FIG. 2 is a detailed configuration diagram of a feedback unit of FIG. 1; FIG.

3 is a flowchart illustrating a predistortion linearization method in a wireless communication terminal according to the present invention.

* Explanation of symbols for the main parts of the drawings

111: buffer unit 112: up-converter

113: automatic gain control amplifier 114: driving amplifier

115: power amplifier 116: first coupler

117: first amplifier 118: second coupler

119: feedback unit 120: the third coupler

121: DSP control unit 130: modem chip

131: baseband processing unit 132: DSP

The present invention relates to a predistortion linearization device and a method thereof in a wireless communication terminal, and more particularly, to a predistortion linearization device and a method for compensating and linearizing the nonlinear characteristics of the transmission terminal of the wireless communication terminal.

In general, the transmitting end of the wireless communication terminal includes many active elements including a power amplifier. These active devices are designed for high power efficiency of wireless communication terminals, but there is a problem in that signal distortion occurs due to the nonlinear characteristics of the active devices themselves. Accordingly, there is a need for a linearization method for preventing signal distortion due to nonlinear characteristics of active devices.

To date, various linearization methods have been used in base stations and repeaters to improve call quality. The predistortion linearization method of the linearization method is a method of pre-distorting the baseband signal in response to the signal distortion caused by the nonlinear characteristics of the active element by adaptively tracking the nonlinear characteristics of the active element.

However, the predistortion linearization method used in a base station, a repeater, and the like is a structure in which the output of the active element is partially feedback, and its structure is complicated and many hardware components are difficult to use in a small device such as a wireless communication terminal. There is a problem.

However, in recent years, wireless communication terminals have been minimized and lightened, and the development and processing speed of modem chips mounted therein have been increased, and the space utilization is increased due to zero IF (Intermediate Frequency) technology, so a simple linearization method can be adopted. Do.

The present invention has been proposed to solve the above problems, using a digital signal processor (DSP) embedded in the modem chip of the wireless communication terminal for power control and linearization of the transmitting end, and extracts the main signal of the transmitting end to 180 degrees phase SUMMARY OF THE INVENTION An object of the present invention is to provide a predistortion linearization device and a method for a predistortion linearity in a wireless communication terminal capable of compensating for the nonlinear characteristics of the transmitting end of a wireless communication terminal by predistorting the main signal of the transmitting end by inverting.

Other objects and advantages of the present invention can be understood by the following description, and will be more clearly understood by the embodiments of the present invention. Also, it will be readily appreciated that the objects and advantages of the present invention may be realized by the means and combinations thereof indicated in the claims.

The apparatus of the present invention for achieving the above object, the feedback means for generating and feedback a signal having a phase difference of 180 degrees with the main signal input to the power amplifier; A first coupler for coupling a signal fed back from the feedback means to a signal divided from the main signal; A first amplifier for amplifying the signal coupled through the first coupler; And a second coupler extracting a part of the main signal inputted to the power amplifier and outputting the partial signal to the feedback means, and combining the signal amplified by the first amplifier with the main signal inputted to the power amplifier to remove the intermodulation component. Characterized in that it comprises a.

In addition, the method of the present invention, the extraction step of extracting a part of the main signal input to the power amplifier; A feedback step of returning the extracted signal and shifting a phase to have a phase difference of 180 degrees with a main signal input to the power amplifier; A first combining step of combining the feedback signal with a signal divided from the main signal; An amplifying step of amplifying the combined signal; And a second combining step of removing the intermodulation component by combining the amplified signal with the main signal input to the power amplifier.

The above objects, features and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, whereby those skilled in the art may easily implement the technical idea of the present invention. There will be. In addition, in describing the present invention, when it is determined that the detailed description of the known technology related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a diagram illustrating an embodiment of applying a predistortion linearization apparatus according to the present invention to a transmitting terminal of a wireless communication terminal.

As shown in FIG. 1, in general, a transmitting end 110 of a wireless communication terminal is connected to a modem chip 130, and the transmitting end 110 is output from a baseband processor 131 of the modem chip 130. Buffer unit 111 for adjusting the input speed of I (In-phase) and Q (Quadrature) signals, up-converter 112 for up-converting the frequency of the signal output from the buffer unit 111 and adding I and Q signals. ), An auto gain control amplifier 113 that adjusts and amplifies the gain of the signal output from the upconverter 112, a drive amplifier 114 that amplifies the signal output from the auto gain control amplifier 113, and a drive amplifier 114 A power amplifier (Power AMP) 115 for power amplifying the signal output from the ().

On the other hand, the predistortion linearization device according to the present invention, as shown in Figure 1, the first coupler for coupling the signal input via the feedback unit 119 to the signal divided at the output terminal of the automatic gain control amplifier 113 ( 116, a first amplifier 117 that amplifies the signal coupled through the first coupler 116, and extracts a part of the main signal of the input terminal of the power amplifier 115, and also amplifies it through the first amplifier 117. A second coupler 118 that couples the received signal to a main signal of the input terminal of the power amplifier 115, a feedback unit 119 that rotates the phase of the main signal extracted through the second coupler 118 by 180 degrees, and returns the feedback signal; In addition, a digital signal processor (DSP) of the modem chip 130 according to a signal extracted through the third coupler 120 and the third coupler 120 that partially extracts a signal of the output terminal of the power amplifier 115. Also referred to as 'DSP', it includes a DSP control unit 121 for controlling 132.

The first coupler 116 couples the signal fed back from the feedback unit 119 to the signal divided at the output terminal of the automatic gain control amplifier 113, and the first amplifier 117 amplifies the combined signal.

In this case, the signal amplified by the first amplifier 117 is a signal in which the main component (Main) is attenuated and the intermodulation component (IMD) is maintained at a predetermined size. The automatic gain control amplifier 113 and the driving amplifier 114 are used. And a phase difference of 180 degrees with the main signal passing through the power amplifier 115.

That is, the signal amplified by the first amplifier 117 attenuates the intermodulation component of the main signal input to the power amplifier 115 to linearize the nonlinearity of the transmitter of the wireless communication terminal.

FIG. 2 is a diagram illustrating a detailed embodiment of the feedback unit of FIG. 1. FIG.

As shown in FIG. 2, the feedback unit 119 of FIG. 1 includes an attenuator 201 for attenuating the signal extracted through the second coupler 118 and a delayer for delaying the attenuated signal through the attenuator 201. 202, and a phase shifter 203 for phase shifting and returning a signal delayed through the delay unit 202.

The DSP controller 121 detects the main signal through the third coupler 120, converts the detected main signal into a digital signal, and outputs the digital signal to the DSP 132 of the modem chip 130.

The DSP 132 generates control parameters for the attenuator 201, the delayer 202, and the phase shifter 203 based on the digital signal received from the DSP controller 121, and outputs the control parameters to the DSP controller 121. The DSP controller 121 controls the attenuator 201, the delayer 202, and the phase shifter 203 based on the control parameter.

3 is a flowchart illustrating a predistortion linearization method in a wireless communication terminal according to the present invention.

As shown in FIG. 3, first, the signal extracted from the power amplifier 115 is attenuated (301), and the attenuated signal is delayed (302).

Next, the delayed signal is phase shifted to have a phase difference of 180 degrees with the main signal of the input terminal of the power amplifier 115 (303).

Subsequently, the signal divided at the output terminal of the automatic gain control amplifier 113 and the phase shifted signal are combined and amplified (304). At this time, the combined amplified signal is a signal in which the size of the main component (Main) is mostly attenuated and the size of the intermodulation component (IMD) is maintained at a predetermined size.

Subsequently, the combined amplified signal is combined with the main signal Main of the input terminal of the power amplifier 115 to maintain the magnitude of the main component Main of the main signal and attenuate the magnitude of the intermodulation component IMD (305).

Finally, the magnitude of the main component Main is maintained and the magnitude of the intermodulation component IMD detects a part of the attenuated main signal to control the attenuation, delay, and phase shift degree (306).

By repeating the above process, the non-linearity of the transmitter of the wireless communication terminal can be linearized. That is, the intermodulation component generated through a plurality of amplification processes is attenuated and the main component is maintained at a predetermined size to linearize the nonlinear characteristics of the active device.

As described above, the method of the present invention may be implemented as a program and stored in a recording medium (CD-ROM, RAM, ROM, floppy disk, hard disk, magneto-optical disk, etc.) in a computer-readable form. Since this process can be easily implemented by those skilled in the art will not be described in more detail.

The present invention described above is capable of various substitutions, modifications, and changes without departing from the technical spirit of the present invention for those skilled in the art to which the present invention pertains. It is not limited by the drawings.

The present invention as described above, by linearizing the wireless communication terminal transmitting end, there is an effect that prevents the base station deterioration due to excessive use of users and contributes to the optimization of the base station cell (CELL).

Claims (6)

Feedback means for generating and returning a signal having a phase difference of 180 degrees with a main signal input to the power amplifier; A first coupler for coupling a signal fed back from the feedback means to a signal divided from the main signal; A first amplifier for amplifying the signal coupled through the first coupler; And A second coupler which partially extracts the main signal inputted to the power amplifier and outputs it to the feedback means, and combines the signal amplified by the first amplifier with the main signal inputted to the power amplifier to remove the intermodulation component; Predistortion linearization device in a wireless communication terminal comprising a. The method of claim 1, The feedback means, An attenuator for attenuating the magnitude of the signal extracted through the second coupler; A delayer for delaying the attenuated signal through the attenuator; And Phase shifter for phase shifting the delayed signal through the delay to have a phase difference of 180 degrees with the main signal input to the power amplifier Predistortion linearization device in a wireless communication terminal comprising a. The method according to claim 1 or 2, A third coupler extracting a part of a signal from an output terminal of the power amplifier; And The signal extracted through the third coupler is converted into a digital signal and transmitted to a digital signal processor of a modem chip, and the attenuator, delayer, and phase shifter are controlled according to a control signal from the digital signal processor. DSP control means Predistortion linearization device in a wireless communication terminal further comprising. An extraction step of partially extracting a main signal input to the power amplifier; A feedback step of returning the extracted signal and shifting a phase to have a phase difference of 180 degrees with a main signal input to the power amplifier; A first combining step of combining the feedback signal with a signal divided from the main signal; An amplifying step of amplifying the combined signal; And A second combining step of removing the intermodulation component by coupling the amplified signal to a main signal input to the power amplifier; Predistortion linearization method in a wireless communication terminal comprising a. The method of claim 4, wherein The feedback step, An attenuating step of attenuating a key of the extracted signal; Delaying the attenuated signal; And Phase shift step of shifting the phase of the delayed delayed signal to have a phase difference of 180 degrees with the main signal input to the power amplifier Predistortion linearization method in a wireless communication terminal comprising a. The method according to claim 4 or 5, A control step of sensing an output of the power amplifier and controlling the attenuation, delay, and phase shift values based on the sensed value Predistortion linearization method in a wireless communication terminal further comprising.

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