KR100660992B1 - Transceiving apparatus in OFDM system and method thereof - Google Patents

Abstract

The present invention provides a transmission / reception apparatus capable of presetting a mapping table in which symbols and block indices having a smallest maximum power-to-average power ratio between symbols of an OFDM system are established, and transmitting and receiving data represented by a symbol constructed in a set mapping table. And a method for dividing the input digital data into blocks to obtain block data, and obtaining the quotient and remainder obtained by dividing the block data values obtained based on the block data into specific values with block indexes and additional information, and block indexes. And a mapping unit for outputting a symbol corresponding to a block index and additional information in a mapping table previously constructed so that and symbols correspond to each other. An S / P converter for converting a symbol, which is serial data input from the mapping unit, into parallel data; An inverse fast Fourier transform unit for converting parallel data input from the S / P converter into an inverse fast Fourier transform unit; And a transmitter for transmitting a signal input from the inverse fast Fourier transform unit as symbol information through the first channel and transmitting additional information input from the mapping unit as additional information through the second channel.

Orthogonal Frequency Division Multiplex, Block, Index, Symbol, Transmit / Receive

Description

Transceiving apparatus in OFDM system and method

1A is a block diagram of a transmitter in an orthogonal frequency division multiplexing system according to an embodiment of the present invention.

1B is a block diagram of a receiver in an orthogonal frequency division multiplexing system according to an embodiment of the present invention.

2A is a flowchart illustrating a transmission method in an orthogonal frequency division multiplexing system according to an embodiment of the present invention.

2B is a flowchart illustrating a receiving method in an orthogonal frequency division multiplexing system according to an embodiment of the present invention.

3A is a block diagram of a transmitter in an orthogonal frequency division multiplexing system according to another embodiment of the present invention.

3B and 3C are block diagrams of a receiving apparatus in a quadrature frequency division multiplexing system according to another embodiment of the present invention.

4A is a flowchart illustrating a transmission method in an orthogonal frequency division multiplexing system according to another embodiment of the present invention.

4B and 4C are flowcharts illustrating a reception method in an orthogonal frequency division multiplexing system according to another embodiment of the present invention.

5A is a diagram illustrating a reduction characteristic of a PAPR of a subcarrier in a transceiver according to the present invention.

5B is a diagram illustrating a comparison between PAPR characteristics in a general OFDM system and PAPR reduction characteristics in a transceiver according to the present invention.

5C is a diagram illustrating a reduction characteristic of PAPR according to the number of additional information in the transmission and reception apparatus according to the present invention.

Explanation of symbols on the main parts of the drawings

100, 300: transmitter 110, 310: mapping unit

120, 320: S / P conversion unit 130, 330: inverse fast Fourier conversion unit

200, 400: receiver 210, 410: fast Fourier transform unit

220, 420: P / S conversion unit 230, 430: demapping unit

The present invention relates to a transmission and reception apparatus and a method of a mobile communication terminal to which an Orthogonal Frequency Division Multiplexing (OFDM) system is applied, and in particular, a peak to average power ratio between symbols in an OFDM system. Preset mapping table constructed by matching symbols with the smallest ratio) or block indices, or preset mapping table that can be obtained as a symbol index by associating modules with blocks. The present invention relates to a transmission and reception apparatus and a method for transmitting and receiving symbols constructed in a mapping table.

In general, an OFDM system is a digital modulation scheme in which data streams having a high data rate are divided into multiple data streams having a low data rate, and are simultaneously transmitted using a plurality of subcarriers, and are widely used in digital communication systems because they are strong in multipath fading. It is becoming.

However, an OFDM system has a very disadvantageous disadvantage of having a high PAPR, and an OFDM signal composed of many independently modulated subcarriers has a large peak-to-average power (PAP) when added synchronously.

Most wireless systems use high-power amplifiers, which cause major losses in RF systems, to achieve maximum output efficiency, which introduces nonlinear distortion in the communication channel because they are usually operated near saturation. . In addition, the change in the amplitude of the OFDM signal is widely distributed with a large PAPR. This large amplitude enters the transmitter power amplifier and causes nonlinear amplification of the input signal. Since this causes severe attenuation of transmission performance, a reduction in PAPR is urgently needed.

Accordingly, several techniques have been proposed for PAPR reduction, and they are classified into three categories as follows.

The first technique is the signal distortion technique. Clipping reduces the peak size by non-linearly distorting the OFDM signal around the peak. Clipping is the simplest and most effective PAPR reduction method. However, this method results in severe in-band and out-of-band clipping noise. This causes a bit error rate (BER) performance reduction in adjacent channel interference (ACI).

The second technique is a coding scheme using a special coded code set that excludes an OFDM signal having a large PAPR. Block coding, one form of coding technique, has the advantage of not causing any out-of-band emissions, but there is no inherent coding scheme to maintain an appropriate coding rate for any number of subcarriers.

The third technique is based on scrambling, and scrambling each OFDM signal with different scrambling sequences and selecting a sequence having the smallest PAPR. This scrambling method generates M different phase shifts for the same input data string, and then selects and sends a column having the lowest PAPR. The M different columns are generated by multiplying the input data string by the N length phase adjusting column. The first cluster phase generally does not change while the 'M-1' phases vary. After that, the row with the lowest PAPR among the M branches is selected. Unlike block coding and clipping methods, this method does not create spectral efficiency and signal distortion, and is known to be effective and flexible. However, this method requires higher order calculations because of the many inverse Fourier transform steps and iterative calculations and has a complex hardware configuration. Therefore, this method requires many inverse Fourier transform steps equivalent to the complex structure in the OFDM transmitter, which is very difficult to realize in practice.

The present invention transmits a symbol constructed in a predetermined mapping table constructed by matching symbols with the smallest PAPR and block indices in an OFDM system, or by transmitting a mapping table constructed as a symbol that can be obtained by modulo operation. In addition, the present invention provides a transmission apparatus and method capable of greatly reducing PAPR and simplifying a calculation process during data transmission.

In addition, an object of the present invention is to significantly reduce the PAPR at the time of data reception by restoring the received data using the block index constructed in a predetermined mapping table constructed by matching the symbols with the smallest PAPR and the block indices in an OFDM system. It provides a receiving apparatus and method that can be.

In addition, an object of the present invention is to provide a receiving apparatus that can implement a hardware configuration more simply by restoring received data by modulo operation using received symbols without using a mapping table in an OFDM system.

According to the present invention for achieving the above object, in the transmission apparatus of an orthogonal frequency division multiplexing system, block data is obtained by dividing input digital data into blocks, and the block data values obtained based on the block data are converted into specific values. A mapping part which obtains the quotient and remainder obtained by dividing the block index and the additional information, and outputs the symbol and the additional information corresponding to the block index in a mapping table which is previously constructed so that the block index and the symbol correspond to each other; A S / P (Serial / Parrel) converter for converting a symbol, which is serial data input from the mapping unit, into parallel data; An inverse fast Fourier transform unit having a size N (N: natural number of 4 or more) for inverse fast Fourier transform (IFFT) of the parallel data input from the S / P converter; And a transmitter for transmitting a signal input from the inverse fast Fourier transform unit as symbol information through a first channel and transmitting additional information input from the mapping unit as additional information through a second channel. Is constructed so as to correspond to the block index by selecting as many blocks as the number of block indexes, symbols having a minimum symbol average power ratio (PAPR) from a symbol collection having a size of 2 ^N.

According to the present invention, in a transmission apparatus of an orthogonal frequency division multiplexing system, a block data is obtained by dividing input digital data into blocks, obtaining block data, and dividing a block data value obtained based on the block data by dividing it by a specific value. A mapping unit which obtains an index and additional information and outputs a symbol corresponding to the block index and the additional information in a mapping table that is previously constructed such that the block index and the symbol correspond to each other; A S / P (Serial / Parrel) converter for converting a symbol, which is serial data input from the mapping unit, into parallel data; An inverse fast Fourier transform unit having a size N (N: natural number of 4 or more) for inverse fast Fourier transform (IFFT) of the parallel data input from the S / P converter; And a transmitter for transmitting a signal input from the inverse fast Fourier transform unit as symbol information through a first channel and transmitting additional information input from the mapping unit as additional information through a second channel. Is constructed to correspond to the block index by selecting as many blocks as a symbol index by performing a modulo operation on the number of blocks from a symbol collection having a size ^2N .

The present invention provides a fast apparatus having a size N (N: natural number of 4 or more) for fast Fourier transform (FFT) of symbol information received through a first channel of a receiver in a receiving apparatus of an orthogonal frequency division multiplexing system. Fourier transform unit; A P / S conversion unit for converting parallel data input from the fast Fourier transform unit into a symbol that is serial data; A block index corresponding to the symbol input from the P / S converter is multiplied by a specific value in a mapping table previously constructed so that a symbol and a block index correspond to each block index information, and are obtained through the second channel of the receiver. And a demapping part for recovering digital data by obtaining a block data value by adding the received additional information to the block index part information.

The present invention provides a fast apparatus having a size N (N: natural number of 4 or more) for fast Fourier transform (FFT) of symbol information received through a first channel of a receiver in a receiving apparatus of an orthogonal frequency division multiplexing system. Fourier transform unit; A P / S conversion unit for converting parallel data input from the fast Fourier transform unit into a symbol that is serial data; The symbol received from the P / S converter is modulated by a predetermined number of blocks, and is multiplied by a specific value to obtain block index information, and is received through a second channel of the receiver. And a demapping unit for recovering digital data by obtaining block data values by adding additional information to the block index unit information.

According to the present invention, in a transmission method of an orthogonal frequency division multiplexing system, a block data is obtained by dividing input digital data into blocks, obtaining block data, and dividing a block data value obtained based on the block data by dividing it by a specific value. Obtaining a symbol corresponding to the block index and the additional information from a mapping table which is obtained by using an index and additional information, and the block index and the symbol are previously constructed; Converting the symbol, which is serial data, into parallel data; A third step of performing inverse fast Fourier transform (IFFT) on the transformed parallel data; And a fourth step of transmitting the converted signal as symbol information through a first channel, and transmitting the generated additional information as additional information through a second channel, wherein the mapping table has a size of 2 ^N (where N is the value). In the third step, from the symbol set having the size of the inverse fast Fourier transform unit, which is a natural number of 4 or more), the symbols having the minimum PAPR (Peak Average Power Ratio) between symbols are as many as the number of blocks. It is selected and constructed to correspond to the block index.

In the transmission method of an orthogonal frequency division multiplexing system, the present invention divides the input digital data into blocks to obtain block data, and divides the quotients and the remainder obtained by dividing the block data values obtained based on the block data by specific values. Obtaining a symbol corresponding to the block index and the additional information from a mapping table which is obtained by using the block index and the additional information, and the block index and the symbol are previously constructed; Converting the symbol, which is serial data, into parallel data; A third step of performing inverse fast Fourier transform (IFFT) on the transformed parallel data; And a fourth step of transmitting the converted signal as symbol information through a first channel, and transmitting the generated additional information as additional information through a second channel, wherein the mapping table has a size of 2 ^N (where N is the value). In the third step, the inverse fast Fourier transform unit modulates the number of blocks from the population of symbols having a natural number equal to or greater than 4 as the size of the inverse fast Fourier transform unit, and selects as many symbols as the symbol index. To correspond to the block index.

According to an aspect of the present invention, there is provided a method of receiving a quadrature frequency division multiplexing system, the method comprising: a first step of performing fast Fourier transform (FFT) on symbol information received through a first channel of a receiver; A second step of converting the converted parallel data into a symbol that is serial data; And multiplying a block index corresponding to the symbol by a specific value in a mapping table previously constructed so that the symbol and the block index correspond to the block index unit information, and obtaining additional information received through the second channel of the receiver unit. And a third step of recovering digital data by obtaining a block data value in addition to the sub information.

According to an aspect of the present invention, there is provided a method of receiving a quadrature frequency division multiplexing system, the method comprising: a first step of performing fast Fourier transform (FFT) on symbol information received through a first channel of a receiver; A second step of converting the converted parallel data into a symbol that is serial data; And multiplying the reconstructed block index obtained by modulo the predetermined number of symbols with a specific value to obtain block index information, and adding additional information received through the second channel of the receiver to the block index information. In addition, a third step of recovering digital data by obtaining a block data value is included.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention.

1A is a block diagram of a transmitter in an orthogonal frequency division multiplexing system according to an embodiment of the present invention.

Referring to FIG. 1A, the transmission device 100 of the present invention divides input digital data into blocks to obtain block data, and divides the quotient and the remainder obtained by dividing the block data value obtained based on the block data by a specific value. A mapping part 110 which obtains a block index and additional information, and outputs a symbol corresponding to the block index and the additional information in a mapping table which is previously constructed so that the block index and the symbol correspond to each other; S / P (Serial / Parrel) converting unit 120 for converting a symbol, which is serial data input from 110, into parallel data, and parallel data input from S / P converting unit 120; IFFT: Inverse Fast Fourier Transform (N: Inverse Fast Fourier Transformation unit 130) having a size N (N: 4 or more natural numbers) and the signal input from the Inverse Fast Fourier Transformation unit 130 through the first channel And a transmitter 140 for transmitting as symbol information and transmitting additional information input from the mapping unit 110 as additional information through a second channel, wherein the mapping table includes symbols between symbols from a population of symbols having a size of ^2N . It is characterized in that it is constructed to correspond to the block index by selecting as many blocks as the number of block indexes, the symbol having a minimum Peak Average Power Ratio (PAPR).

The mapping unit 110 is configured with a mapping table as shown in Table 1 below.

 Block Index (q)     Symbol Patterns        0 S ₀ (17)        One S ₁ (29)        2 S ₂ (37)        . . .         . . .        31 S ₃₁ (149)

In the mapping table, the block index is a quotient (q) obtained by dividing a decimal value, which is an example of a data value, by a predetermined block length, which is an example of a specific value, in the mapping unit 110. These are values corresponding to the smallest predetermined symbol, respectively. Here, 17, which can be said to be a symbol of symbol S ₀ (17), is "S ₁ (29), S ₂ (37), ...", "29, 37,-, *" of S _k (*) and the minimum PAPR. In a transmission according to the present invention, this value is transmitted. However, '*' in S _k (*) is an arbitrary number for the sake of understanding. When the size of the inverse fast Fourier transform is N, such a mapping table selects a block having a minimum number of blocks, which is the number of block indices, from among a symbol collection having a size of 2 ^N and having a minimum symbol average power ratio (PAPR). Characterized in that it is constructed to correspond to the index. Here, the symbols represent data consisting of the number of bits corresponding to the size N of the inverse fast Fourier transform. For example, the block index corresponding to the symbol S ₂ is '2'.

When the digital data is input, the mapping unit 110 storing the mapping table divides the input digital data into blocks, obtains a data value based on the divided block data, and then, as shown in Equation 1 below. The decimal value, which is an example of the obtained data values, is divided by the predetermined block length, which is an example of a specific value, to calculate the quotient, which is the block index, and the remainder, which is additional information. At this time, the mapping unit 110 obtains a decimal value of the data by using the bit input most preferentially in the block division of the input data as MSB (Most Significant Bit), or inputs the highest priority in the block division of the input data. Decimal value of data is obtained by making LSB (Least Significant Bit).

Decimal value of data = quotient (q) * block length + rest (p)

Here, the block length is the length of digital data divided into one block, and the block length is determined by the number of blocks corresponding to the number of block indexes and the remainder. In the present invention, the number of block indexes is 32, and Since the type is set to '8', the block length becomes '8'.

Accordingly, when binary data '00010101' is input to the mapping unit 110, the mapping unit 110 corresponds to a block corresponding to the remainder p corresponding to the quotient q as shown in Equation 2 below. Get index and additional information

21 = 2 × 8 + 5

In Equation 2, '21' is a decimal value of data '00010101', '2' is a quotient (q) corresponding to a block index, '8' is a block length, and '5' is added. The remainder is p.

When the block index and the additional information are determined as described above, the mapping unit 110 determines the S / P indicated by '37', which is a symbol of the symbol S ₂ 37 corresponding to the block index '2' in the predetermined mapping table. Output to the converter 120. The mapping unit 110 outputs a binary value '101' of additional information '5', and the additional information output is transmitted through a specific channel, for example, a pilot channel. As such, the additional information transmitted through the pilot channel is used to demap the digital data mapped by the mapping unit 110 at the receiving side.

The S / P conversion unit 120 is a symbol of the symbols constructed in the mapping table set in the mapping unit 110, for example, '37' which may be referred to as a symbol of the symbol S ₂ (37). If input, the serial data symbol '37' is converted into parallel data and then output the converted parallel data to the inverse fast Fourier transform unit (IFFT) 130.

The inverse fast Fourier transform unit (IFFT) 130 converts the parallel data input from the S / P converter 120 at high speed to inverse Fourier transform and outputs it to the transmitter 140.

The transmitter 140 transmits the signal input from the inverse fast Fourier transform unit 130 as symbol information through the first channel and the additional information input from the mapping unit 110 as additional information through the second channel. .

1B is a block diagram of a receiver in an orthogonal frequency division multiplexing system according to an embodiment of the present invention.

Referring to FIG. 1B, the reception apparatus 200 of the present invention includes a size N (N: 4 or more natural number) for fast Fourier transform (FFT) of symbol information received through the first channel of the receiver 240. Fast Fourier transform section 210, P / S converter 220 for converting parallel data input from fast Fourier transform section 210 into a symbol that is serial data, and a symbol and a block index In the mapping table constructed in advance, the block index corresponding to the symbol input from the P / S converter 220 is multiplied by a specific value to obtain block index information, and is received through the second channel of the receiver 240. And a demapping part 230 for restoring the digital data by obtaining the block data value by adding the information to the block index information.

When the fast Fourier transform unit 210 receives the symbol information received through the first channel of the receiver 240, Fourier transforms the input symbol information at high speed to output parallel data to the P / S converting unit 220. .

The P / S converter 220 converts the parallel data input from the fast Fourier transformer 210 into serial data and outputs the converted symbol to the demapping unit 230.

When the symbol which is the serial data converted by the P / S converter 220 and additional information, for example, '37' which is a symbol of symbol S ₂ 37 and additional information '101' are input, demapping The unit 230 outputs digital data by performing demapping as follows.

Since the mapping table of [Table 1], which is the same as that of the transmitter 100, is set in the demapping unit 230, the demapping unit 230 as shown in [Equation 1] and [Equation 2] may be used. The block index '2' constructed in the mapping table corresponding to the input symbol S ₂ is multiplied by the predetermined block length '8', and the multiplied value '16' and the decimal value '5' of the additional information to be input are added. Calculate the decimal value '21'. The demapping unit 230 converts the decimal value '21' obtained as described above into binary serial data '00010101' and outputs it.

FIG. 2A is a flowchart illustrating a transmission method in an orthogonal frequency division multiplexing system according to an embodiment of the present invention, and illustrates a process of transmitting data by the transmitting apparatus of the present invention shown in FIG. 1A.

Referring to FIG. 2A, the transmitter 100 divides input digital data into blocks to obtain block data (S210), and divides the quotient and remainder obtained by dividing a block data value obtained based on the block data by a specific value. A symbol corresponding to the block index and the additional information are generated in a mapping table previously constructed such that the block index and the symbol correspond to each other (S211).

The transmitter 100 converts the symbol which is serial data into parallel data (S213), and then converts the converted parallel data into an inverse fast Fourier transform (S214).

In addition, the transmitting apparatus 100 transmits the converted signal as symbol information through a first channel and transmits the generated additional information as additional information through a second channel (S215).

Here, the mapping table is constructed to correspond to the block index by selecting as many blocks as the number of block indexes, symbols having a minimum symbol average power ratio (PAPR) from a symbol collection having a size of 2 ^N. do.

The process of receiving by the receiving apparatus 200 the frequency signal transmitted through the above process will be described below.

FIG. 2B is a flowchart illustrating a receiving method in an orthogonal frequency division multiplexing system according to an embodiment of the present invention, and illustrates a process of receiving data by the receiving apparatus of the present invention shown in FIG. 1B.

Referring to FIG. 2B, the reception apparatus 200 performs fast Fourier transform on symbol information received through the first channel of the receiver 240 (S220), and converts the converted parallel data into a symbol that is serial data (S221). .

The receiving device 200 obtains the block index information by multiplying a specific value by a block index corresponding to the symbol from a mapping table in which a symbol and a block index are previously constructed (S222), and the second of the receiving unit 240 is obtained. The block data value is obtained by adding the additional information received through the channel to the block index information to restore digital data (S223).

3A is a block diagram of a transmitter in an orthogonal frequency division multiplexing system according to another embodiment of the present invention.

Referring to FIG. 3A, the transmission device 300 of the present invention divides input digital data into blocks to obtain block data, and divides the quotient and remainder obtained by dividing the block data value obtained based on the block data by a specific value. A mapping unit 310 which obtains a block index and additional information, and outputs a symbol corresponding to the block index and the additional information in a mapping table which is previously constructed such that the block index and the symbol correspond to each other, and is input from the mapping unit 310. S / P (Serial / Parrel) Converter 320 and S / P Converter 320 for converting symbols, which are serial data, to be parallel data, and inverse fast Fourier transform (IFFT: Inverse Fast). Symbol information received from the inverse fast Fourier transform unit 330 having a size N (N: 4 or more natural numbers) to be transformed by Fourier Transform and the inverse fast Fourier transform unit 330 through a first channel Transmission, comprising a transmission section 340 for transmitting the additional information inputted from the mapping unit further information via the second channel, and the mapping table is a module to the block number from the symbol sum recruitment having size 2 ^N (modulo It is constructed to correspond to the block index by selecting the number of symbols that can be a symbol index by the operation).

The mapping unit 310 is set to the mapping table as shown in the following [Table 2].

 Block Index (q)     Symbol Patterns        0 S ₀ (96)        One S ₁ (33)        2 S ₂ (130)        . . .         . . .        31 S ₃₁ (159)

The mapping table of [Table 4] is constructed to correspond to a block index by selecting a symbol number that can be a symbol index by performing a modulo operation on the number of blocks from a symbol collection having a size ^2N . It features. Here, the symbols represent data each consisting of a predetermined number of bits. Looking at the contents of the mapping table as an example, '96', which is a symbol of symbol S ₀ (96), corresponds to block index '0', and symbol of symbol S ₁ (33) corresponds to block index '1'. This may be referred to as '33', and block index '2' corresponds to '130', which is a symbol of symbol S ₂ (130), and block index '31' corresponds to symbol S ₃₁ (159). '159', which is a symbol, corresponds. Here, the symbols represent data consisting of the number of bits corresponding to the size N of the inverse fast Fourier transform. For example, the block index corresponding to the symbol S ₂ is '2'.

When the digital data is input, the mapping unit 310 storing the mapping table divides the input digital data into blocks, obtains a data value based on the partitioned block data, and then, as shown in Equation 1 above. A decimal value, which is an example of the obtained data value, is divided by a predetermined block length, which is an example of a specific value, to calculate the quotient, which is a block index, and the remainder, which is additional information. In this case, the mapping unit 310 obtains a decimal value of the data by using the bit input most preferentially in the block division of the input data as MSB (Most Significant Bit), or inputs the highest priority in the block division of the input data. Decimal value of data is obtained by making LSB (Least Significant Bit).

As such, when the block index and the additional information are determined, the mapping unit 310 determines the S / P indicated by '37', which is a symbol of the symbol S ₂ 130 corresponding to the block index '2' in the predetermined mapping table. Output to the converter 320. In addition, the mapping unit 310 outputs a binary value '101' of additional information '5', wherein the additional information output is transmitted through a specific channel, for example, a pilot channel. As such, the additional information transmitted through the pilot channel is used to demap the digital data mapped by the mapping unit 310 at the receiving side.

The S / P conversion unit 320 is one symbol among the symbols constructed in the mapping table set in the mapping unit 110, for example, '130', which is a symbol of the symbol S ₂ 130. When input, the serial symbol '130' is converted into parallel data and then output the converted parallel data to the inverse fast Fourier transform unit (IFFT) 330.

The inverse fast Fourier transform unit (IFFT) 330 converts the parallel data inputted from the S / P converter 320 to the inverse Fourier at high speed and outputs it to the transmitter 340.

The transmitter 340 transmits the signal input from the inverse fast Fourier transform unit 330 as symbol information through the first channel and the additional information input from the mapping unit 310 as additional information through the second channel. .

3B is a block diagram of a receiving apparatus in an orthogonal frequency division multiplexing system according to another embodiment of the present invention.

Referring to FIG. 3B, the reception apparatus 400 of the present invention includes a size N (N: 4 or more natural number) for fast Fourier transform (FFT) of symbol information received through the first channel of the receiver 440. Fast Fourier transform unit 410, P / S converter 420 for converting parallel data input from fast Fourier transform unit 410 into a symbol that is serial data, and a symbol and a block index In the mapping table constructed in advance, the block index corresponding to the symbol input from the P / S converter 420 is multiplied by a specific value to obtain the block index information, and is received through the second channel of the receiver 440. And a demapping part 430 for restoring digital data by obtaining block data values in addition to the block index information.

When the fast Fourier transform unit 410 receives the symbol information received through the first channel of the receiver 440, Fourier transforms the received symbol information at high speed to output parallel data to the P / S converting unit 420. .

The P / S converter 420 converts the parallel data input from the fast Fourier converter 410 into serial data and outputs the converted symbol to the demapping unit 430.

When the symbol which is the serial data converted by the P / S converter 420 and additional information, for example, '130' which is a symbol of the symbol S ₂ 130 and the additional information '101' are input, demapping The unit 230 outputs digital data by performing demapping as follows.

In the demapping unit 430, since the mapping table of [Table 2], which is the same as that of the transmitting device 200, is set, the demapping unit 430 as shown in [Equation 1] and [Equation 2], The block index '2' constructed in the mapping table corresponding to the input symbol S ₂ is multiplied by the predetermined block length '8', and the multiplied value '16' and the decimal value '5' of the additional information to be input are added. Calculate the decimal value '21'. The demapping unit 430 converts the decimal value '21' obtained as described above into binary serial data '00010101' and outputs it.

3c is a block diagram of a receiving apparatus in an orthogonal frequency division multiplexing system according to another embodiment of the present invention.

Referring to FIG. 3C, the receiving apparatus 500 of the present invention includes a fast Fourier having a size N (N: natural number of 4 or more) for fast Fourier transform (FFT) of symbol information received through a first channel. A conversion unit 510, a P / S conversion unit 520 for converting parallel data input from the fast Fourier transform unit 510 into a symbol that is serial data, and a mapping that is previously constructed so that a symbol and a block index correspond to each other In the table, the block index corresponding to the symbol input from the P / S converter 520 is multiplied by a specific value to obtain block index information, and block data is added to the block index information by adding additional information received through a second channel. And a demapping part 530 for reconstructing the digital data by obtaining the value.

The fast Fourier transform unit 510 converts the symbol information received through the first channel into Fast Fourier transform and outputs the P / S converter 520.

The P / S converter 520 converts the parallel data input from the fast Fourier converter 510 into a symbol that is serial data and outputs the same to the demapping unit 530.

For example, if the received symbol '130' which is the serial data converted by the P / S converter 520 and the binary data of the received additional information is '101', the demapping unit 530 is as follows. Restore the received data. However, the mapping table may or may not be set in the demapping unit 530.

When the mapping table is not set in the demapping unit 530, when a reception symbol output from the P / S converter 520 is input, the demapping unit 530 first blocks configured as shown in [Table 2]. Modulo of the received symbols is performed using one block number among the numbers. That is, the demapping unit 530 performs "received data 130 modulo 32" using a predetermined number of blocks '32'. In this modulo process, the demapping unit 530 divides the received data '130' by a predetermined number of blocks '32' and obtains a residual value '2' except for a quotient. The remaining value '2' thus obtained is the predetermined value. The block index described in the mapping table.

After the block index is obtained using the received data and the predetermined number of blocks, the demapping unit 530, as shown in [Equation 1] and [Equation 2], uses the block index '2' obtained through modulo and A predetermined block length '8' is multiplied, and the decimal value '21' of the data received through the antenna is calculated by adding the multiplied value '16' and the decimal value '5' of the inputted additional information. The demapping unit 530 converts the calculated decimal value '21' of the received data into binary serial data '00010101' and outputs it.

Accordingly, in the reception apparatus according to another embodiment of the present invention, since the mapping table is not used, an internal configuration can be implemented more simply. As a result, a multicarrier different from the OFDM system to which the present invention is applied can be implemented. It can be applied very easily to a system.

A process of transmitting / receiving data by a transceiver device according to another embodiment of the present invention having the configuration and function as described above will be described with reference to a flowchart.

4A is a flowchart illustrating a transmission method in an orthogonal frequency division multiplexing system according to another embodiment of the present invention, and illustrates a process of transmitting data by the transmitting apparatus of the present invention shown in FIG. 3A.

Referring to FIG. 4A, the transmitter 300 divides the input digital data into blocks to obtain block data (S410), and divides the quotient and the remainder obtained by dividing the block data value obtained based on the block data by a specific value. A symbol corresponding to the block index and the additional information are generated from a mapping table that is pre-established so that the block index and the symbol correspond to each other (S411).

The transmitter 300 converts the symbol, which is serial data, into parallel data (S413), and converts the converted parallel data into an inverse fast Fourier (S414).

In addition, the transmitter 300 transmits the converted signal as symbol information through a first channel and transmits the generated additional information as additional information through a second channel (S415).

The mapping table may be constructed to correspond to a block index by selecting a symbol that can be a symbol index by performing a modulo operation on the number of blocks from a symbol collection having a size 2 ^N and corresponding to the block index. .

FIG. 4B is a flowchart illustrating a receiving method in an orthogonal frequency division multiplexing system according to another embodiment of the present invention, and illustrates a process of receiving data by the receiving apparatus of the present invention shown in FIG. 3B.

Referring to FIG. 4B, the reception apparatus 400 performs fast Fourier transform on the symbol information received through the first channel of the reception unit 440 (S420), and converts the converted parallel data into a symbol that is serial data (S421). .

The receiving device 400 obtains the block index information by multiplying a specific value by a block index corresponding to the symbol from a mapping table previously constructed so that the symbol and the block index correspond (S422), and the second channel of the receiving unit 440. The block data value is obtained by adding additional information received through the block index unit information to restore digital data (S423).

FIG. 4C is a flowchart illustrating a receiving method in an orthogonal frequency division multiplexing system according to another embodiment of the present invention, and illustrates a process of receiving data by the receiving apparatus of the present invention shown in FIG. 3C.

Referring to FIG. 4C, the reception apparatus 500 converts symbol information received through the first channel of the reception unit 540 into a fast Fourier transform (S430).

Subsequently, the receiving apparatus 500 converts the converted parallel data into a symbol that is serial data (S431).

The reception apparatus 500 multiplies the reconstructed block index obtained by modulo operation of the symbol with a predetermined number of blocks and obtains the block index information by multiplying a specific value (S432). The second channel of the reception unit 540 is obtained. The block data value is obtained by adding the additional information received through the block index information to restore the digital data (S433).

5A is a diagram illustrating a reduction characteristic of a PAPR of a subcarrier in a transceiver according to the present invention.

FIG. 5A illustrates the degree of attenuation of the PAPR by dotted lines and solid lines in the transmission and reception apparatuses 100 and 200 and the transmission and reception apparatuses 300 and 500, respectively. For example, since the dotted line is below the solid line in the same number of blocks, the PAPR attenuation in the transmitting and receiving apparatuses 100 and 200 is smaller than that of the transmitting and receiving apparatuses 300 and 500. In addition, the solid lines representing the characteristics of the transceivers 300 and 500 indicate that the PAFT attenuation is less since the size of the IFFT is 8 than that of the case 16.

5B is a diagram illustrating a comparison between PAPR characteristics in a general OFDM system and PAPR reduction characteristics in a transceiver according to the present invention.

FIG. 5B shows that both the transceivers 100 and 200 having two and four additional information bits and the transceivers 300 and 500 have exceeded the probability of PAPR. Since the number of mapping symbols varies depending on the additional information bits, this indicates the probability of PAPR. Here, the dotted line represents the characteristics of the transmission and reception apparatuses 100 and 200, and the solid line represents the characteristics of the transmission and reception apparatuses 300 and 500. In addition, the transceiver of the present invention having four additional information bits has more mapping symbols and thus shows better performance.

5C is a diagram illustrating a reduction characteristic of PAPR according to the number of additional information in the transmission and reception apparatus according to the present invention.

5C compares the performance of the PAPR of the transceiver of the present invention and the selective mapping (SLM) method using binary phase shift keying (BPSK) when N = 16. As the additional information increases, the PAPR decreases. The transceivers 100 and 200 approach in theory more than SLM, which is the ideal method for PAPR reduction because of the mapped symbol type with the lowest PAPR.

The signal transmitted from the transceiver 300, 500 is selected from a fixed code set. At this time, the codes in the code set have a high correlation. In the SLM method, selectable codes are generated by some independent random columns. Therefore, when using the SLM method as compared with the transmission and reception apparatuses 300 and 500 of the present invention, a further reduction in PAPR can be obtained.

In FIG. 5C, the dotted line with the uppermost circle represents the transceiver 300 and 500, the line with the center square represents the SLM method, and the dotted line with the triangle represents the transceiver 100 and 200. The comparison results show that the transceivers 100 and 200 are the closest to the theoretical value, so that the performance is the best.

Although the technical spirit of the present invention has been described in detail according to the above-described preferred embodiment, it should be noted that the above-described embodiment is for the purpose of description and not of limitation. In addition, those skilled in the art will understand that various embodiments are possible within the scope of the technical idea of the present invention.

As described above, the present invention has the following effects by transmitting and receiving a symbol of a mapping table constructed by associating symbols with the smallest PAPR and block indices among symbols of an OFDM system.

First, the present invention can increase the number of bits of additional information to increase the performance of the PAPR.

Second, the present invention can reduce the loss of the frequency signal by transmitting and receiving data using the symbols and block index constructed in the mapping table.

Third, the present invention can adjust the trade-off problem according to practical requirements by reducing the PAPR when data is transmitted and received and considering the size of the block size of the mapping table and the number of bits of the additional information.

Fourth, the present invention can simplify the signal transmission process by using the symbols and block index constructed in the mapping table during the transmission and reception process.

Claims (36)

delete In the transmission apparatus of the orthogonal frequency division multiple system, Block data is obtained by dividing the input digital data into blocks, and the quotient and remainder obtained by dividing the block data values obtained on the basis of the block data by specific values are obtained as block indexes and additional information, and the block indexes and symbols in advance correspond to each other. A mapping part configured to output a symbol corresponding to the block index and the additional information in a mapping table constructed; A serial / parallel (S / P) converter for converting a symbol, which is serial data input from the mapping unit, into parallel data; An inverse fast Fourier transform unit having a size N (N: natural number of 4 or more) for inverse fast Fourier transform (IFFT) of the parallel data input from the S / P converter; And A transmitter for transmitting a signal input from the inverse fast Fourier transform unit as symbol information through a first channel and transmitting additional information input from the mapping unit as additional information through a second channel; The mapping table is constructed to correspond to the block index by selecting as many blocks as the number of block indexes, symbols having a minimum symbol average power ratio (PAPR) from a symbol collection having a size of 2 ^N , And the block data value is a decimal number. The method of claim 2, And the specific value is a block length corresponding to the number of bits of the block. The method of claim 2, And the additional information is converted into binary data and output. In the transmission apparatus of the orthogonal frequency division multiple system, Block data is obtained by dividing the input digital data into blocks, and the quotient and remainder obtained by dividing the block data values obtained on the basis of the block data by specific values are obtained as block indexes and additional information, and the block indexes and symbols in advance correspond to each other. A mapping unit configured to output a symbol corresponding to the block index and the additional information in a mapping table constructed; A S / P (Serial / Parrel) converter for converting a symbol that is serial data input from the mapping unit into parallel data; An inverse fast Fourier transform unit having a size N (N: natural number of 4 or more) for inverse fast Fourier transform (IFFT) of the parallel data input from the S / P converter; And A transmitter for transmitting a signal input from the inverse fast Fourier transform unit as symbol information through a first channel and transmitting additional information input from the mapping unit as additional information through a second channel; The mapping table is constructed so as to correspond to a block index by selecting a symbol that can be a symbol index by performing a modulo operation on the number of blocks from a symbol population having a size 2 ^N and corresponding to the block index. . The method of claim 5, And the block data value is a decimal number. The method according to claim 5 or 6, And the specific value is a block length corresponding to the number of bits of the block. The method of claim 6, And the additional information is converted into binary data and output. In the receiving apparatus of an orthogonal frequency division multiple system, A fast Fourier transform unit having a size N (N: natural number of 4 or more) for fast Fourier transform (FFT) of symbol information received through a first channel of the receiver; A P / S conversion unit for converting parallel data input from the fast Fourier transform unit into a symbol that is serial data; And A block index corresponding to the symbol input from the P / S converter is multiplied by a specific value in a mapping table previously constructed so that a symbol and a block index correspond to each block index information, and are obtained through the second channel of the receiver. And a demapping part for recovering digital data by obtaining block data values by adding the received additional information to the block index information. The method of claim 9, And the mapping table is constructed so as to correspond to a block index by selecting as many blocks as the minimum number of symbols among symbols having a peak average power ratio (PAPR) from a population of symbols having a size of ^2N . The method of claim 9, The mapping table is constructed to correspond to a block index by selecting as many blocks as a symbol index by performing a modulo operation on a predetermined number of blocks from a symbol collection having a size ^2N . Receiving device. The method according to any one of claims 9 to 11, And the block data value is a decimal number. The method according to any one of claims 9 to 11, And the specific value is a block length corresponding to the number of bits of the block. The method of claim 12, And the additional information is converted into decimal data and input to the demapping unit. In the receiving apparatus of an orthogonal frequency division multiple system, A fast Fourier transform unit having a size N (N: natural number of 4 or more) for fast Fourier transform (FFT) of symbol information received through a first channel of the receiver; A P / S conversion unit for converting parallel data input from the fast Fourier transform unit into a symbol that is serial data; And The symbol received from the P / S conversion unit is multiplied by a specific value to the reconstructed block index obtained by modulo operation with a predetermined number of blocks to obtain block index information, and is received through the second channel of the receiving unit. And a demapping unit for restoring digital data by obtaining block data values by adding additional information to the block index unit information. The method of claim 15, And the recovery block index is a decimal number. The method of claim 15, And the specific value is a block length corresponding to the number of bits of the block. The method of claim 16, And the additional information is converted into decimal data and input to the demapping unit. delete In the transmission method of an orthogonal frequency division multiplexing system, Block data is obtained by dividing the input digital data into blocks, and the quotient and remainder obtained by dividing the block data values obtained on the basis of the block data by specific values are obtained as block indexes and additional information, and the block indexes and symbols in advance are corresponding. A first step of generating a symbol corresponding to the block index and the additional information in the constructed mapping table; Converting the symbol, which is serial data, into parallel data; A third step of performing inverse fast Fourier transform (IFFT) on the transformed parallel data; And A fourth step of transmitting the converted signal as symbol information through a first channel and transmitting the generated additional information as additional information through a second channel, The mapping table has a minimum PAPR (Peak Average Power Ratio) between symbols from a population of symbols having a size of ^2N (N is the size of the inverse fast Fourier transform unit transforming the inverse fast Fourier in the third step, which is a natural number of four or more). Is constructed to correspond to the block index by selecting the symbol to be the number of blocks, which is the number of block indexes, And the block data value is a decimal number. The method of claim 20, And the specific value is a block length corresponding to the number of bits of the block. The method of claim 20, And the additional information is converted into binary data and output. In the transmission method of an orthogonal frequency division multiplexing system, Block data is obtained by dividing the input digital data into blocks, and the quotient and remainder obtained by dividing the block data values obtained on the basis of the block data by specific values are obtained as block indexes and additional information, and the block indexes and symbols in advance correspond to each other. A first step of generating a symbol corresponding to the block index and the additional information in the constructed mapping table; Converting the symbol, which is serial data, into parallel data; A third step of performing inverse fast Fourier transform (IFFT) on the transformed parallel data; And A fourth step of transmitting the converted signal as symbol information through a first channel and transmitting the generated additional information as additional information through a second channel, The mapping table is a modulo operation of the number of blocks from a population of symbols having a size 2 ^N (N is the size of the inverse fast Fourier transform unit for transforming inverse fast Fourier in the third step) is a natural number of four or more symbols. The transmission method characterized in that it is constructed so as to correspond to the block index by selecting as many blocks as the number of symbols that can be an index. The method of claim 23, wherein And the block data value is a decimal number. The method of claim 23 or 24, And the specific value is a block length corresponding to the number of bits of the block. The method of claim 24, And the additional information is converted into binary data and output. In the reception method of an orthogonal frequency division multiplexing system, A first step of Fast Fourier Transform (FFT) of symbol information received through a first channel of the receiver; A second step of converting the converted parallel data into a symbol that is serial data; And A block index corresponding to the symbol is multiplied by a specific value in a mapping table previously constructed so that a symbol and a block index correspond to the block index information, and the additional information received through the second channel of the receiver is used as the block index information. In addition, the third step of restoring digital data by obtaining a block data value Receiving method comprising a. The method of claim 27, The mapping table is constructed so as to correspond to the block index by selecting as many blocks as the number of symbols having a minimum Peak Average Power Ratio (PAPR) between symbols from a symbol collection having a size of ^2N (where N is a natural number of 4 or more). A reception method characterized by the above. The method of claim 27, The mapping table is a block index by selecting a symbol that can be a symbol index by performing a modulo operation on a predetermined number of blocks from a symbol population having a size 2 ^N (where N is a natural number of 4 or more). And a reception method constructed so as to correspond to. The method according to any one of claims 27 to 29, And the block data value is a decimal number. The method according to any one of claims 27 to 29, The specific value is a reception method, characterized in that the block length corresponding to the number of bits of the block. The method of claim 30, And the additional information is converted into decimal data. In the reception method of an orthogonal frequency division multiplexing system, A first step of Fast Fourier Transform (FFT) of symbol information received through a first channel of the receiver; A second step of converting the converted parallel data into a symbol that is serial data; And Multiply the reconstructed block index obtained by modulo operation with a predetermined number of blocks to obtain a block index information by multiplying a specific value, and add additional information received through the second channel of the receiver to the block index information. Third step of restoring digital data by obtaining block data values Receiving method comprising a. The method of claim 33, wherein And the recovery block index is a decimal number. The method of claim 33, wherein The specific value is a reception method, characterized in that the block length corresponding to the number of bits of the block. The method of claim 34, wherein And the additional information is converted into decimal data and input to the demapping unit.

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