KR101599985B1 - Apparatus and method for digital transmitter in mobile communication system - Google Patents

Abstract

The present invention relates to a digital transmission apparatus and method in a mobile communication system, and more particularly to a digital transmission apparatus applied in a multi-band multi-mode, in which a structure of a digital transmission apparatus is simplified by using BPSDM, DAC, The present invention relates to an apparatus and method for improving the performance of a digital power amplifier, comprising: a restoration signal generator for up-converting a signal to be transmitted and generating a restoration signal for use in an analog power amplifier; A FIR filter for selecting a channel of a signal to be transmitted and eliminating noise of the channel, and a digital amplifier using a signal obtained by combining the reconstructed signal and the noise-removed modulated signal as an input signal.

Digital transmission, digital up-converter, transmission device, noise cancellation

Description

TECHNICAL FIELD [0001] The present invention relates to a digital transmission apparatus and a digital transmission method in a mobile communication system,

The present invention relates to a digital transmission apparatus and method in a mobile communication system, and more particularly to a digital transmission apparatus applied in a multi-band multi-mode, in which a structure of a digital transmission apparatus is simplified by using BPSDM, DAC, And an apparatus and method for improving performance.

Generally, in a mobile communication system, a digital up converter of a transmitting apparatus performs interpolation, filtering, and frequency shift using a digital signal processing technique. . More specifically, the digital up-converter up-converts the baseband signal input from the channel card to an intermediate frequency signal, and performs interpolation to convert the data rate of the signal Data Rate) and performs Digital Filtering to remove noise outside the signal band required for communication.

In a general transmission apparatus, a BPSDM (Bandpass Sigma Delta Modulator) having an advantage of noise shaping is used to prevent noise of a transmission apparatus from being passed to a reception apparatus. Also, since the transmission apparatus uses BPSDM, it can support a high-performance digital amplifier, thereby maximizing the efficiency of the transmission apparatus.

However, since the transmission apparatus uses a BPSDM signal, a separate filter is required to remove noise signals generated on both sides in addition to the bandwidth used by the transmission apparatus.

The filter for removing the noise signal eliminates the noise of the both side band of the BPDSM output, but a general filter is not a filter that can select a channel by a band selection filter.

Accordingly, the BPDSM attenuates noise existing on both sides except for the bandwidth of the channel of the transmitting apparatus itself using a filter capable of selecting a channel.

The conventional transmission apparatus as described above has a problem in that it is expensive to use a plurality of filters and can not efficiently use electric power.

Therefore, when the BPSDM signal is used to improve the performance of the digital receiving apparatus, the noise signal generated on both sides of the bandwidth used by the transmitting apparatus is removed without using a separate filter There is a need for an apparatus and a method for achieving the above objects.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an apparatus and method for improving the performance of a digital transmission apparatus in a mobile communication system.

It is another object of the present invention to provide an apparatus and method for removing noise existing on both sides of a bandwidth using BPSDM in a mobile communication system without using a separate filter.

It is another object of the present invention to provide an apparatus and method for removing noise existing on both sides of a bandwidth by using a BPSDM and a channel selectable filter in a mobile communication system.

According to an aspect of the present invention, a data transmission apparatus of a mobile communication system generates a restoration signal for up-converting a signal to be transmitted and then using an analog signal in a digital power amplifier An FIR filter for modulating an up-converted signal and then selecting a channel of a signal to be transmitted to remove a noise of the channel, a signal combining the recovered signal and the modulated signal from which the noise is removed, And a digital amplifier using the input signal as an input signal.

According to a second aspect of the present invention, there is provided a data transmission method for a mobile communication system, comprising: up-converting a signal to be transmitted; generating a restoration signal for using an analog signal in a digital power amplifier A step of modulating the up-converted signal and then removing a noise of the corresponding channel using an FIR filter; and a step of using a signal obtained by combining the generated restored signal and the modulated signal from which noise is removed as an input signal of the digital amplifier The method comprising the steps of:

As described above, according to the present invention, in order to improve the performance of a digital transmission apparatus in a mobile communication system, BPSDM is used to remove noise existing on both sides of a bandwidth, without using a separate filter. And combines the FIR filter with the DAC to prevent the use of separate filters to remove noise signals on both sides beyond the bandwidth used by the transmitter. Further, the present invention improves the performance of the transmitting apparatus by using the analog output signal of the DAC in the digital power amplifier.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

In the following description, a digital transmission apparatus for eliminating noise existing on both sides of a bandwidth using BPSDM without using a separate filter in order to improve the performance of a digital transmission apparatus in a mobile communication system will be described.

1 is a block diagram showing the configuration of a transmission apparatus according to a preferred embodiment of the present invention. In the following description, FIG. 2 is a diagram illustrating a data transmission process of a transmission apparatus according to an exemplary embodiment of the present invention.

1, the transmitting apparatus includes a digital up-converter 101, a modulator 103, a FIR filter 105, and a modulator 106. The BPSDM (bandpass sigma delta modulator) A digital-to-analog converter (DAC) 107, a power amplifier (PA) 109, and a restored signal generating unit 110. The restored signal generating unit 110 may include, A digital / analog converter (DAC) 112 and an amplifier 114. The digital / analog converter (DAC)

The digital up conversion unit 101 of the transmission apparatus up converts the baseband signal to an intermediate frequency signal to up-convert the signal to be transmitted and transmits the up-converted signal to the BPSDM 103 do. The BPSM 103 modulates a signal received from the digital up-converter 101, that is, a signal converted by the digital up-converter 101, and transmits the modulated signal to the FIR filter 105.

The FIR filter 105 selects a channel of the signal modulated by the BPSDM 103 and processes the signal to remove noise existing on both sides of the bandwidth of the corresponding channel. That is, the FIR filter 105 removes noise of a signal having no noise as shown in FIG. 2 (a), and processes the signal as shown in FIG. 2 (b).

The digital-to-analog converter 107 converts the digital signal from which the noise has been removed by the FIR filter 105 into an analog signal and provides it to the power amplifier 109. Here, the digital-to-analog converter 107 may be a binary current DAC or a ternary DAC.

The power amplifier 109 receiving the analog signal from the digital-to-analog converter 107 combines the restored signal provided from the restored signal generator 110 and the analog signal received from the digital-to-analog converter 107, And processes the noise-removed signal by the filter 105 to restore it to the original signal.

The restoration signal generation unit 110 generates a restoration signal that refers to a signal for using an efficient digital power amplifier 109, that is, a switching PA, by using the output signal of the digital up-conversion unit 101. That is, the restored signal generating unit 110 generates a restored signal by using an input signal of a digital PA 105 which uses a digital signal as an input signal, that is, a signal from which the noise is removed from the FIR filter 105, And restores the original signal using the restored signal.

The restoration signal generator 110 receives the signal converted by the digital up-converter 101 and converts the signal into an analog signal through a digital-to-analog converter 112, And transmits the generated restoration signal to the digital power amplifier 109 through the amplifier 114. [

The above describes a digital transmission apparatus for removing noise existing on both sides of a bandwidth by using BPSDM without using a separate filter in order to improve the performance of a digital transmission apparatus in a mobile communication system. A method for enhancing the performance of a digital transmission apparatus by using BPSDM using the apparatus according to a preferred embodiment of the present invention and eliminating noise existing on both sides of the bandwidth, without using a separate filter, will be described.

2 is a diagram illustrating a data transmission process of a transmission apparatus according to an exemplary embodiment of the present invention.

Referring to FIG. 2, the transmitter uses a noise shaping advantage by using a BPSDM (bandpass sigma delta modulator) as a digital transmission apparatus, thereby preventing transmission noise from being shifted to reception noise. However, The present invention is intended to supplement existing transmitters that require additional filters to remove sideways noise signals.

FIG. 2 (a) is a diagram illustrating a signal converted by a modulator of a transmitting apparatus according to a preferred embodiment of the present invention.

2 (a) generates a noise signal on both sides of the bandwidth other than the signal bandwidth 210 generated in the conventional transmission apparatus as described above.

The above-mentioned signal is a digital signal. In the conventional transmitting apparatus, a separate filter (external smoothing filter) has to be used to generate an analog signal. At this time, the used filter is for eliminating noise signals existing on both sides of the bandwidth, but the filter is a filter which can not select a channel by a band selection filter. Accordingly, in the conventional transmission apparatus, a channel selection filter is additionally used to attenuate noise signals on both sides except for the bandwidth of the channel, thereby causing many problems in the design of the transmission apparatus.

FIG. 2B is a diagram illustrating a signal in which noise is removed from a transmitting apparatus according to a preferred embodiment of the present invention.

Referring to FIG. 2B, the transmitter removes the noise of a corresponding channel in the transmitter according to the present invention, and the transmitter removes the noise of the corresponding channel using an FIR filter.

That is, the transmission apparatus of the present invention as described above can solve the problem of adding a separate filter due to the problem that the filter of the existing transmission apparatus can not select a channel.

3 is a flowchart illustrating a data transmission process of a transmitting apparatus according to an exemplary embodiment of the present invention.

Referring to FIG. 3, the transmitting apparatus performs an operation for a data transmission event, that is, a data transmission procedure, in step 301. FIG.

Thereafter, the transmitter proceeds to step 303 so as to up-convert the signal to be transmitted. Here, the transmission apparatus refers to a process of up-converting a baseband signal to an intermediate frequency signal through a digital up-conversion unit 101 of the transmission apparatus.

Thereafter, the transmitting apparatus proceeds to step 305 and processes it to generate a restored signal. Here, the restored signal refers to a signal for using an efficient digital power amplifier 109, that is, a switching PA, by using an output signal of a digital / analog converter (DAC)

In detail, the digital PA 109 uses a digital signal as an input signal, and the transmitting apparatus according to the present invention converts an analog signal from the DAC 107 into an input signal of the digital power amplifier 109 So as to enable efficient power use.

Here, the transmitting apparatus processes the restoration signal generating unit 110 to generate a restoration signal in which the output of the DAC 107 is combined with the hybrid EER or ET method.

Thereafter, the transmitter proceeds to step 307, modulates the signal converted in step 303, and then proceeds to step 309 to select a channel. Here, the transmitting apparatus selects a channel to remove noise using an FIR filter 105 capable of channel selection.

Thereafter, in step 311, the transmitter removes the noise of the channel selected in step 309. In step 313, the transmitter generates a modulated signal by removing noise in step 311 using the restored signal restored in step 305 Signal. Here, the transmitter processes the modulated signal as shown in FIG. 2 (a) so that the FIR filter removes noise as shown in FIG. 2 (b).

In addition, the transmitter transmits the clipped signal due to the use of the switching PA to the Envelope amp, that is, a restoration signal output from the amplifier 114 of the restoration signal generator 110 of the transmission apparatus, And recombine to restore the original signal.

Then, the transmitter proceeds to step 315 and transmits a restored signal to the original signal, that is, data to be transmitted.

That is, the transmitter uses a bandpass sigma delta modulator (BPSDM) for noise shaping and removes an external filter using a DAC such as a binary current DAC or a ternary DAC to control power efficiency. In addition, the transmission apparatus uses a hybrid EER or ET scheme in combination with an output signal of a DAC, which is an analog signal, in order to use an efficient switching PA. In this case, even if the DAC output becomes the RF analog signal having the PAPR, the switching PA is used instead of the linear PA, and the clipped signal due to the use of the switching PA is recombined in the switching PA with the signal coming from the envelope amp to restore the original signal .

Accordingly, the transmission apparatus can provide a power efficiency reduction effect by using a switching PA.

Thereafter, the transmitting apparatus terminates the present algorithm.

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments, but is capable of various modifications within the scope of the invention. Therefore, the scope of the present invention should not be limited by the illustrated embodiments, but should be determined by the scope of the appended claims and equivalents thereof.

1 is a block diagram showing the configuration of a transmitting apparatus according to a preferred embodiment of the present invention;

FIG. 2 (a) illustrates a signal converted by a modulator of a transmitting apparatus according to a preferred embodiment of the present invention,

2 (b) is a diagram illustrating a noise-removed signal in a transmitting apparatus according to an exemplary embodiment of the present invention,

3 is a flowchart illustrating a data transmission process of a transmitting apparatus according to an exemplary embodiment of the present invention.

Claims (8)

A method of transmitting data in a mobile communication system, A process of modulating a transmission signal using a BPSDM (Bandpass Sigma Delta Modulator); Removing a noise of the transmission signal modulated using a FIR (Finite Impulse Response) filter and a DAC (Digital Analog Converter); Reconstructing the original signal based on the transmission signal from which the noise is removed and the transmission signal before modulation; And amplifying the restored original signal. delete delete A data transmission apparatus of a mobile communication system, A BPSDM (Bandpass Sigma Delta Modulator) for modulating a transmission signal; A filter unit for removing noise of the modulated transmission signal; And And a switching power amplifier for restoring the original signal based on the transmission signal from which the noise is removed and the transmission signal before modulation and amplifying the original signal. 5. The method of claim 4, The filter unit includes: A Finite Impulse Response (FIR) filter and a digital analog converter (DAC). delete 5. The method of claim 4, Further comprising a restoration signal generator for generating an input signal to the power amplifier based on the transmission signal before being modulated. 8. The method of claim 7, Wherein the restoration signal generator comprises: A digital analog converter (DAC) and an envelope amplifier (Envelope Amplifier).

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