KR20080044717A - Apparatus and method for transmitting uwb of ofdm system - Google Patents

Abstract

A UWB(Ultra-Wide Band) transmission apparatus of an OFDM(Orthogonal Frequency-Division Multiplexing) system and a UWB transmission method using the same are provided to enhance accuracy in removing an image signal by increasing a guard frequency interval of a baseband signal and an image signal. A channel coding unit(110) codes data bits according to an MB OFDM(Orthogonal Frequency-Division Multiplexing) PHY standard. An interleaving and mapping unit(120) rearranges the coded data bits and performs severally a mapping operation. A symbol modulation unit(130) modulates the interleaved and mapped data bits to QPSK(Quadrature Phase Shift Keying) symbols by using a QPSK modulation method. A preamble and guard interval insertion unit(150) inserts a preamble and guard interval into a time domain signal. A DAC(Digital Analog Converter)(170) converts I(Inphase) and Q(Quadrature) elements of the time domain signal by using a digital to analog conversion method. An LPF(Low Pass Filter)(180) removes an image from an output signal of the DAC and transmits the corresponding signal through an antenna.

Description

ＵＷＢTransmission method and apparatus thereof of ODFM system {Apparatus and method for transmitting UWB of OFDM system}

1 is a block diagram showing a UWB transmission modem in a typical OFDM system,

2 illustrates a signal output through a DAC included in a UWB transmission modem of a general OFDM system;

3 is a block diagram showing a UWB transmission modem of an OFDM system according to an embodiment of the present invention;

4 is a view showing a signal output through the DAC provided in the UWB transmission modem of the OFDM system according to an embodiment of the present invention,

5 is a block diagram showing a UWB transmission modem of an OFDM system according to another embodiment of the present invention;

6 is a view showing a signal processing method of an IFFT unit according to an embodiment of the present invention;

7 is a diagram comparing OFDM symbol output and conventional OFDM symbol output according to an embodiment of the present invention;

8 is a diagram illustrating filter tap coefficients of an interpolator in a UWB transmitting modem according to an embodiment of the present invention;

9 is a diagram illustrating an interpolator filter structure of a UWB transmitting modem according to an embodiment of the present invention;

10 is a flowchart illustrating a method of operating a UWB transmitting modem according to an embodiment of the present invention; and

11 is a flowchart illustrating a method of operating a UWB transmitting modem according to another embodiment of the present invention.

* Description of the symbols for the main parts of the drawings *

100: UWB transmission modem 110: channel encoding unit

120: interleaving and mapping unit 130: symbol modulator

140: IFFT unit

150: preamble and protective section insertion unit

160: interpolator 170: DAC

180: LPF

The present invention relates to a UWB transmission method and apparatus therefor, and more particularly, to an UWB transmission method and apparatus for an OFDM system for easily removing an image signal of transmission data in a UWB transmission apparatus.

BACKGROUND Wireless communication systems, such as orthogonal frequency division multiplexing (OFDM) systems, generally transmit and receive data using a plurality of carriers. In particular, an ultra-wide band (UWB) system, such as MultiBand OFDM Alliance (MBOA) or 802.15.3a, transmits and receives data in 528 MHz bandwidth using about 128 independent OFDM carriers. Accordingly, data input to the OFDM system is modulated and then transmitted on a plurality of carriers.

1 is a block diagram showing a UWB transmission modem in a typical OFDM system.

Referring to FIG. 1, the UWB transmission modem 10 of the OFDM system includes a channel encoding unit 11, an interleaving and mapping unit 12, a symbol modulation unit 13, an IFFT (Inverse Fast Fourier Transform) unit 14, A preamble and a guard interval inserting unit 15, a digital analog converter (DAC) 16, and a low pass filter (LPF) 17 are included.

Here, the channel encoding unit 11 codes data bits received according to the MB OFDM PHY standard, and the interleaving and mapping unit 12 rearranges the encoded bits and then performs one or more mapping operations on the rearranged data bits. Perform.

The symbol modulator 13 converts the interleaved and iteratively mapped data bits into QPSK symbols or symbols of other modulation schemes through Quadrature Phase Shift Keying (QPSK) modulation schemes or other modulation schemes.

The IFFT unit 14 converts the converted symbol into a waveform in a time domain called an OFDM symbol, and then the preamble and guard interval inserter 15 inserts the preamble and the guard interval into the transformed OFDM symbol.

The DAC 16 converts the I (Inphase) and Q (Quadrature) components of the OFDM symbol from digital to analog, respectively, so that the converted signal has a spectrum repeated every 528 MHz at 528 M samples / s.

Here, the spectrum repeated every 528 MHz is composed of a baseband signal and an image signal.

The LPF 17 deletes the image signal from the signal converted by the DAC 16, so that only the pure baseband signal is transmitted through the antenna.

2 is a diagram illustrating a signal output through a DAC included in a UWB transmission modem of a general OFDM system.

Referring to FIG. 2, the signal output through the DAC 16 of the UWB transmission modem 10 is 528M samples / s, which includes a baseband signal existing in the -264 to 264 MHz band and the rest of the image signal. Able to know.

Thus, LPF 17 removes the image signal from the signal input from DAC 16, including the cut-off frequency characteristic of a shown in FIG.

On the other hand, the UWB transmission modem of the current OFDM system narrows the guard frequency interval between the baseband signal and the image signal during the modulation process, and has a problem in that it is not possible to accurately remove only the image signal in response to such a case by the limited LPF function. have.

An object of the present invention for solving the above problems is to increase the guard frequency interval of the baseband signal and the image signal in the data modulation process of the OFDM system to facilitate the implementation of the UWB transmission method and apparatus of the OFDM system To provide.

Ultra-wide band (UWB) transmission apparatus of the present invention for achieving the above object of the present invention, IFFT (Inverse Fast Fourier Transform) for converting the signal of the frequency domain coded and modulated into a signal of the over-sampled time domain It includes).

The IFFT unit may be configured to convert the signal in the frequency domain into a signal in the oversampled time domain according to the following equation.

,

은 샘플링 시간 간격이 n의 0.5배 임.

,

Is a sampling time interval of 0.5 times n.

: 주파수 영역의 신호,

: 시간 영역의 신호)(

= Signal in the frequency domain,

: Signal in time domain)

Preferably, the UWB transmitting apparatus includes a channel coding unit for coding the received data bits according to the MB OFDM PHY standard; An interleaving and mapping unit for rearranging the coded data bits and performing a plurality of mapping operations; A symbol modulator for modulating the interleaved and mapped data bits into QPSK symbols through a Quadrature Phase Shift Keying (QPSK) modulation scheme; A preamble and guard period inserter for inserting a preamble and a guard period into the signal in the time domain; A digital analog converter (DAC) for converting I (Inphase) and Q (Quadrature) components of the signal in the time domain from digital to analog, respectively; It further includes a low pass filter (LPF) to remove the image signal from the signal output from the DAC and to transmit the signal through the antenna.

The UWB transmitting apparatus of the present invention for achieving the object of the present invention as described above, converts a signal in the frequency domain is coded and modulated into an OFDM symbol which is a signal in the time domain, the prefix and suffix of the OFDM symbol an IFFT unit configured to further include a suffix diagonally in front and rear of the OFDM symbol; And an interpolator configured to oversample the signal of the OFDM symbol, including at least one filter tap.

The IFFT is such that N * P prefixes and suffixes are further diagonally included in the front and rear ends of the OFDM symbol, wherein P is the number of parallel implementations when data is processed in parallel in the implementation of the UWB transmission modem. Is characterized in that it is calculated according to the following equation.

, N_Taps : 상기 보간부의 필터 탭 개수

, N _Taps : number of filter taps in the interpolation unit

The interpolator may have an implementation proportional to the number of filter taps and an accuracy of a filter tap coefficient.

The interpolator may perform a convolution operation between the input signal and the at least one filter tap coefficient to output the oversampled signal.

Preferably, the UWB transmitting apparatus includes a channel coding unit for coding the received data bits according to the MB OFDM PHY standard; An interleaving and mapping unit for rearranging the coded data bits and performing one or more mapping operations; A symbol modulator for modulating the interleaved and mapped data bits into QPSK symbols through a QPSK modulation scheme; A preamble and guard interval inserter for inserting a preamble and a guard interval into the OFDM symbol; A DAC for converting the I and Q components of the oversampled OFDM symbol from digital to analog respectively; And removing the image signal of the signal output from the DAC and transmitting the LPF through the antenna.

The UWB transmission method of the present invention for achieving the above object of the present invention comprises the steps of: coding and modulating the received data bits; Converting the signals in the coded and modulated frequency domain into signals in an oversampled time domain; Converting the I and Q components of the oversampled time domain signal from digital to analog respectively; Removing the image signal of the converted signal and transmitting the same through an antenna.

The step of converting the oversampled time domain signal is characterized by the following equation.

,

은 샘플링 시간 간격이 n의 0.5배 임.

,

Is a sampling time interval of 0.5 times n.

: 주파수 영역의 신호,

: 시간 영역의 신호)(

= Signal in the frequency domain,

: Signal in time domain)

Coding and modulating the received data bits may comprise: coding the received data bits according to an MB OFDM PHY specification; Reordering the coded data bits and performing a plurality of mappings; And converting the data bits into QPSK symbols through a QPSK modulation scheme.

The converting of the signal in the time domain into an analog may include inserting a preamble and a guard interval into the digital signal in the time domain and converting the signal into the analog.

The UWB transmission method of the present invention for achieving the above object of the present invention comprises the steps of: coding and modulating the received data bits; Converting the coded and modulated signals in the frequency domain into OFDM symbols, which are signals in the time domain; Allowing the prefix and suffix of the OFDM symbol to be further included diagonally in front and rear of the OFDM symbol; Performing oversampling on the signal of the OFDM symbol; Converting the I and Q components of the OFDM symbol from digital to analog respectively; Removing the image signal of the converted signal and transmitting the same through an antenna.

The step of allowing the prefix and suffix of the OFDM symbol to be further included in diagonal lines at the front and rear ends of the OFDM symbol may include N * P prefixes and suffixes in the OFDM symbol. Is the number of history implementations in the case of parallel processing of data on the implementation of the UWB transmission modem, wherein N is calculated according to the following equation.

, N_Taps : 상기 보간부의 필터 탭 개수

, N _Taps : number of filter taps in the interpolation unit

The performing of the oversampling may include performing the oversampling through a convolution operation between a signal of the OFDM symbol and a plurality of filter tap coefficients.

The oversampling of the signal of the OFDM symbol may include performing the oversampling after inserting a preamble and a guard interval into the OFDM symbol.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, in describing in detail the operating principle of the preferred embodiment of the present invention, if it is determined that the detailed description of the related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

In addition, the same reference numerals are used for parts having similar functions and functions throughout the drawings.

3 is a block diagram illustrating an ultra-wide band (UWB) transmission modem of an orthogonal frequency division multiplexing (OFDM) system according to an embodiment of the present invention.

As shown in FIG. 3, the UWB transmission modem 100 includes a channel encoding unit 110, an interleaving and mapping unit 120, a symbol modulation unit 130, an inverse fast fourier transform (IFFT) unit 140, The preamble and the guard interval insertion unit 150, a digital analog converter (DAC) 170, and a low pass filter (LPF) 180 may be included.

Here, the channel encoding unit 110 codes data bits received according to the MB OFDM PHY standard, and the interleaving and mapping unit 120 rearranges the encoded bits and performs one or more mapping operations on the rearranged data bits. Perform.

That is, the interleaving and mapping unit 120 rearranges the data bits as adjacent subcarriers in the received data are often subjected to similar multipaths and fading conditions. Mapping is done in the same order or in the same order.

Accordingly, the symbol modulator 130 converts the interleaved and iteratively mapped bits into QPSK symbols or other modulation schemes through a quadrature phase shift keying (QPSK) modulation scheme or another modulation scheme. Here, the QPSK symbol is characterized in that 128 complex signals are composed of one block.

The IFFT unit 140 converts a signal in a frequency domain converted into a QPSK or other modulation scheme symbol into a wave signal in a time domain called an OFDM symbol.

(128개의 복소 신호)를

로 먼저 변화시킨 후, 이로부터 256개의 독립된 시간 영역 복소 신호

를 출력할 수 있다.Such an IFFT unit 140 is a signal of each frequency domain input from the symbol modulator 130 according to Equation 1 below.

(128 complex signals)

First, then 256 independent time-domain complex signals

You can output

,

은 샘플링 시간 간격이 n의 0.5배 임.

,

Is a sampling time interval of 0.5 times n.

: 주파수 영역의 신호,

: 시간 영역의 신호)(

= Signal in the frequency domain,

: Signal in time domain)

(128개의 복소 신호)를 128개의 시간 영역 신호

로 변환하여 출력한다.On the other hand, the general IFFT unit 140, the signal of each frequency domain input from the symbol modulator 130 according to the following equation (2)

128 time-domain signals (128 complex signals)

Convert to and print it out.

)를 출력하는 것이다.That is, the IFFT unit 140 of the present invention performs oversampling to obtain 256 IFFTs at a sample rate that is twice as large as that of the conventional IFFT unit 140, thereby obtaining every 256 time-domain complex signals (

) Is printed.

The preamble and guard interval inserter 150 inserts the preamble and the guard interval into the OFDM symbol converted by the IFFT unit 140, and the DAC 170 is an I (Inphase) and Q (Quadrature) component of the OFDM symbol. Are converted from digital to analog, so that the converted signal has a spectrum repeated every 1056 MHz at 1056 M samples / s.

Here, 1056M samples / s has only a frequency change for the image signal without a frequency change for the transmitted baseband signal.

That is, the DAC 170 outputs the spectrum as shown in FIG. 4 by the IFFT unit 140 which has oversampled.

4 is a diagram illustrating a signal output through a DAC included in a UWB transmission modem of an OFDM system according to an embodiment of the present invention.

Referring to FIG. 4, a signal output through the DAC 170 of the UWB transmission modem 100 is 1056M samples / s, and includes a baseband signal existing in the -264 to 264 MHz band and the rest of the image signal. There is a wide guard frequency gap between the baseband signal and the image signal.

Accordingly, the LPF 180 of the UWB transmission modem 100 easily removes an image signal from a signal output from the DAC 170 and allows only a pure baseband signal to be transmitted through an antenna.

Next, the UWB transmission modem 100 performing oversampling through an interpolator will be described.

5 is a block diagram illustrating a UWB transmission modem of an OFDM system according to another embodiment of the present invention.

As shown in FIG. 5, the UWB transmission modem 100 includes a channel encoding unit 110, an interleaving and mapping unit 120, a symbol modulation unit 130, an IFFT unit 140, a preamble, and a guard interval insertion unit ( 150, the interpolator 160, the DAC 170, and the LPF 180.

Here, the channel encoding unit 110 codes data bits received according to the MB OFDM PHY standard, and the interleaving and mapping unit 120 rearranges the encoded bits and performs one or more mapping operations on the rearranged data bits. Perform.

That is, the interleaving and mapping unit 120 rearranges the data bits as adjacent subcarriers in the received data are often subjected to similar multipaths and fading conditions. Mapping is done in the same order or in the same order.

The symbol modulator 130 converts the interleaved and iteratively mapped bits into a QPSK symbol or a symbol of another modulation scheme through a QPSK modulation scheme or another modulation scheme.

The IFFT unit 140 converts a signal in a frequency domain converted into a QPSK or other modulation scheme symbol into a wave signal in a time domain called an OFDM symbol.

In this case, when the IFFT unit 140 outputs the converted QFDM symbol as it is, 128 samples of each OFDM symbol are used to prevent the distortion of the signal from the front and rear of the OFDM symbol due to the interpolation unit 160 described later. N * P prefixes and suffixes are subjected to oblique signal processing as shown in FIG.

를 나타낸다. (N_Taps : 보간부의 탭 개수)Here, P represents the number of history implementation in the case of parallel processing data in the implementation of the UWB transmission modem 100, N is

Indicates. (N _Taps : Number of taps in interpolation part)

6 is a diagram illustrating a signal processing method of an IFFT unit according to an exemplary embodiment of the present invention.

As illustrated in FIG. 6, the IFFT unit 140 may allow the prefix and suffix of the N clock duration from the 128 samples of every OFDM symbol to be included in the front and rear ends of each OFDM symbol diagonally. 6 illustrates an example in which P is 1.

On the other hand, since there is a guide time interval between each OFDM symbol, even if the prefix and suffix are included before and after the OFDM symbol, interference between each OFDM symbol does not occur, so there is no problem in the implementation of the UWB transmission modem 100.

7 is a diagram comparing an OFDM symbol output and a conventional OFDM symbol output according to an embodiment of the present invention.

As shown in Fig. 7, (a) shows a conventional OFDM symbol output, and (b) shows an OFDM symbol output for the present invention, where each OFDM symbol of the present invention is N before and after the conventional OFDM symbol. You can see that it increases by * P. 7 illustrates an example in which P is 1.

Meanwhile, in the OFDM symbol output from the IFFT unit 140, the preamble and the guard interval are inserted by the preamble and the guard interval inserter 150, and the OFDM symbol is oversampled by the interpolator 160. That is, the interpolator 160 may cause every OFDM symbol to be oversampled twice in the time domain.

Here, the interpolator 160 may include at least one filter tap, and may have an implementation proportional to the number of filter taps included and the accuracy of filter tap coefficients.

8 is a diagram illustrating filter tap coefficients of an interpolator in a UWB transmission modem according to an embodiment of the present invention.

The filter tap coefficient of the interpolator 160 as shown in FIG. 8 does not exceed the transmitter constellation error range defined in the MBOA PHY standard.

9 is a diagram illustrating an interpolator filter structure of a UWB transmitting modem according to an embodiment of the present invention.

Referring to FIG. 9, it may be appreciated that the interpolator 160 performs a convolution operation on input data and filter tap coefficients. 9 illustrates an example in which P is 1 and the filter tap coefficients are not symmetrical.

On the other hand, the interpolation unit 160 may have a structure in which the size of the circuit becomes small if the values of C_0 to C_N-1 have a symmetrical structure due to the characteristics of the filter tap. Will have

The DAC 170 has a spectrum repeated every 1056 MHz at 1056 M samples / s by the interpolation unit 160 that doubles the input OFDM symbol.

That is, the DAC 170 outputs the spectrum as shown in FIG. 4 by the interpolator 160 which has oversampled, so that the LPF 180 only receives an image signal from the signal output from the DAC 170. Clearly, the pure baseband signal is transmitted through the antenna.

As described above, the present invention allows the IFFT unit 140 to perform 256 IFFT in the oversampling in the UWB transmission modem 100 so that the LPF 180 can be easily implemented, or the interpolation unit 160 is further added. Can be configured.

Next, an operation method of the UWB transmission modem 100 having the above-described configuration will be described with reference to the accompanying drawings.

10 is a flowchart illustrating a method of operating a UWB transmitting modem according to an embodiment of the present invention.

As shown in FIG. 10, when data to be transmitted through the equipped antenna is received, the UWB transmission modem 100 codes the received data bits according to the MB OFDM PHY standard (S101), and encodes the encoded data bits. After reordering, one or more mapping operations are performed on the reordered data bits (S102).

In addition, the UWB transmission modem 100 converts the encoded data bits into QPSK symbols or other modulation scheme symbols through QPSK modulation schemes or other modulation schemes (S103), which are referred to as OFDM symbols. Convert to, but converts to 256 IFFT (S104).

(128개의 복소 신호)의 크기를

로 먼저 변화시킨 후, 이로부터 256개의 시간 영역 복소 신호

를 생성함으로, 주파수 영역의 신호보다 2배 증가된 샘플 속도로 256 IFFT를 획득하여 매 256개의 시간 영역 복소 신호

를 생성하는 것이다.That is, the UWB transmission modem 100 according to the above equation 1, the signal in the frequency domain

The size of (128 complex signals)

First, then 256 time-domain complex signals

By generating 256 IFFTs at a sample rate twice the signal in the frequency domain, every 256 time-domain complex signals

To generate.

The UWB transmission modem 100 inserts a preamble and a guard interval into the OFDM symbol (S105), and converts the I and Q components of the OFDM symbol from digital to analog, respectively, and the converted signal is 1056 MHz at 1056 M samples / s. Each time to have a repeated spectrum (S106).

In addition, the UWB transmission modem 100 removes an image signal included every 1056M samples / s (S107), and allows only pure baseband signals to be transmitted through the antenna (S108).

11 is a flowchart illustrating a method of operating a UWB transmitting modem according to another embodiment of the present invention.

As shown in FIG. 11, when data to be transmitted through the equipped antenna is received, the UWB transmission modem 100 codes the received data bits according to the MB OFDM PHY standard (S201), and encodes the encoded data bits. After reordering, one or more mapping operations are performed on the reordered data bits (S202).

Subsequently, the UWB transmitting modem 100 converts the encoded data bits into QPSK symbols or symbols of other modulation schemes through QPSK modulation or other modulation schemes (S203), and then waves signals in a time domain called OFDM symbols. Is converted to (S204).

In order to prevent distortion of a signal that may occur in front and rear of the converted OFDM symbol, the UWB transmit modem 100 may include N * P prefix suffixes of the 128 samples of every OFDM symbol. Signal processing is further included in the front and rear ends (S205).

를 나타낸다. (N_Taps : 보간부의 탭 개수)Here, P represents the number of history implementation in the case of parallel processing data in the implementation of the UWB transmission modem 100, N is

Indicates. (N _Taps : Number of taps in interpolation part)

The UWB transmission modem 100 inserts a preamble and a guard interval into the OFDM symbol (S206) and uses the interpolator including at least one or more filter taps so that the OFDM symbol is oversampled twice in the time domain ( S207).

The I and Q components of the OFDM symbol are converted from digital to analog, respectively, so that the converted signal has a spectrum repeated every 1056 MHz at 1056 M samples / s (S208), and then the image signal included every 1056 M samples / s is obtained. By removing (S208), only the pure baseband signal is transmitted through the antenna (S209).

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and it is common in the art that various substitutions, modifications, and changes can be made without departing from the technical spirit of the present invention. It will be apparent to those skilled in the art.

As described above, the UWB transmission method and apparatus therefor of an OFDM system according to the present invention allow the UWB transmission modem to increase the output sampling frequency without distortion of the output data through oversampling, thereby preventing the guard frequency interval between the baseband signal and the image signal. By increasing this, it is possible to increase the accuracy of image signal removal.

Claims (17)

In the ultra-wide band (UWB) transmission apparatus of an orthogonal frequency division multiplexing (OFDM) system, An apparatus for transmitting UWB including an Inverse Fast Fourier Transform (IFFT) unit for converting a signal in a coded and modulated frequency domain into a signal in an oversampled time domain. The method of claim 1, The IFFT unit, And a signal in the frequency domain is converted into a signal in the oversampled time domain according to the following equation.

,

Is a sampling time interval of 0.5 times n. (

= Signal in the frequency domain,

: Signal in time domain) The method of claim 1, A channel coding unit for coding the received data bits according to the MB OFDM PHY standard; An interleaving and mapping unit for rearranging the coded data bits and performing a plurality of mapping operations; A symbol modulator for modulating the interleaved and mapped data bits into QPSK symbols through a Quadrature Phase Shift Keying (QPSK) modulation scheme; A preamble and guard period inserter for inserting a preamble and a guard period into the signal in the time domain; A digital analog converter (DAC) for converting I (Inphase) and Q (Quadrature) components of the signal in the time domain from digital to analog, respectively; And And a low pass filter (LPF) which removes an image signal from the signal output from the DAC and then transmits the corresponding signal through an antenna. In the UWB transmitting apparatus of the OFDM system, IFFT unit converts the signal in the frequency domain coded and modulated into an OFDM symbol which is a signal in the time domain, and further includes a prefix and a suffix of the OFDM symbol diagonally before and after the OFDM symbol. ; And And an interpolation unit including at least one filter tap to perform oversampling of the signal of the OFDM symbol. The method of claim 4, wherein IFFT, In the OFDM symbol, N * P prefixes and suffixes are further included diagonally in the front and rear ends, P is the number of history implementations in the case of parallel processing of data in the implementation of the UWB transmission modem, N is calculated according to the following equation.

, N _Taps : number of filter taps in the interpolation unit The method of claim 4, wherein The interpolation unit, And a degree of implementation proportional to the number of filter taps and the accuracy of filter tap coefficients. The method of claim 4, wherein The interpolation unit, And performing a convolution operation between the input signal and the at least one filter tap coefficient to output the oversampled signal. The method of claim 4, wherein A channel coding unit for coding the received data bits according to the MB OFDM PHY standard; An interleaving and mapping unit for rearranging the coded data bits and performing one or more mapping operations; A symbol modulator for modulating the interleaved and mapped data bits into QPSK symbols through a QPSK modulation scheme; A preamble and guard interval inserter for inserting a preamble and a guard interval into the OFDM symbol; A DAC for converting the I and Q components of the oversampled OFDM symbol from digital to analog respectively; And And an LPF which transmits through the antenna by removing the image signal of the signal output from the DAC. In the UWB transmission method of the OFDM system, Coding and modulating the received data bits; Converting the signals in the coded and modulated frequency domain into signals in an oversampled time domain; Converting the I and Q components of the oversampled time domain signal from digital to analog respectively; And And removing the image signal of the converted signal and transmitting the same through an antenna. The method of claim 9, And converting the oversampled time domain signal into a signal according to the following equation.

,

Is a sampling time interval of 0.5 times n. (

= Signal in the frequency domain,

: Signal in time domain) The method of claim 9, Coding and modulating the received data bits, Coding the received data bits according to an MB OFDM PHY standard; Reordering the coded data bits and performing a plurality of mappings; And And converting the data bits into QPSK symbols through a QPSK modulation scheme. The method of claim 9, Converting the signal in the time domain to analog, And inserting a preamble and a guard interval into the digital signal in the time domain and converting the preamble and the protection period into the analog. In the UWB transmission method of the OFDM system, Coding and modulating the received data bits; Converting the coded and modulated signals in the frequency domain into OFDM symbols, which are signals in the time domain; Allowing the prefix and suffix of the OFDM symbol to be further included diagonally in front and rear of the OFDM symbol; Performing oversampling on the signal of the OFDM symbol; Converting the I and Q components of the OFDM symbol from digital to analog respectively; And And removing the image signal of the converted signal and transmitting the same through an antenna. The method of claim 13, The step of allowing the prefix and suffix of the OFDM symbol to be further included diagonally in the front and rear of the OFDM symbol, In the OFDM symbol, N * P prefixes and suffixes are further included diagonally in the front and rear ends, P is the number of history implementations in the case of parallel processing of data in the implementation of the UWB transmission modem, N is calculated according to the following equation.

, N _Taps : number of filter taps in the interpolation unit The method of claim 13, The oversampling may include: And performing the oversampling through a convolution operation between the signal of the OFDM symbol and a plurality of filter tap coefficients. The method of claim 13, Coding and modulating the received data bits, Coding the received data bits according to an MB OFDM PHY standard; Reordering the coded data bits and performing a plurality of mappings; And And converting the data bits into QPSK symbols through a QPSK modulation scheme. The method of claim 13, The oversampling of the signal of the OFDM symbol may include: And inserting a preamble and a guard interval into the OFDM symbol and performing the oversampling.

Images