KR102232791B1 - Transmitter, receiver and controlling method thereof - Google Patents

Abstract

The transmitting device is started. The transmission device inserts a pilot into a frame generator that generates a frame including a frame start symbol, a data symbol, and a frame closing symbol, a frame start symbol, a data symbol, and a frame end symbol, It includes a pilot and reserved tone insertion unit for inserting a reserved tone so as not to overlap with a pilot insertion position, and a transmission unit for transmitting a frame in which the pilot and reserved tone are inserted. Accordingly, it is possible to insert the reserved tone while avoiding collision between the pilot and the reserved tone, and it is possible to reduce the PAPR based on the inserted pilot and the reserved tone.

Description

Transmission device, reception device, and control method thereof {TRANSMITTER, RECEIVER AND CONTROLLING METHOD THEREOF}

The present invention relates to a transmission apparatus, a reception apparatus, and a control method thereof, and more particularly, to a transmission apparatus, a reception apparatus and a control method thereof using an OFDM scheme.

Recently, broadcast communication services are becoming multifunctional and high-quality broadband. In particular, with the development of electronic technology, the spread of portable broadcasting devices such as high-definition digital TVs and high-end smart phones is increasing, and accordingly, demands for various reception methods and various service support for broadcasting services are increasing.

In response to this request, as an example, a broadcast communication standard such as DVB-T2 (Digital Video Broadcasting the Second Generation Terrestrial) has been developed. DVB-T2 (Digital Video Broadcasting the Second Generation Terrestrial) is a second-generation European terrestrial digital broadcasting standard that has been adopted as a standard in more than 35 countries around the world, including Europe, and has improved the performance of DVB-T, which is currently being serviced. -T2 has realized an increase in transmission capacity and high bandwidth efficiency by applying the latest technologies such as LDPC (Low Density Parity Check) code and 256QAM modulation method. Accordingly, it is possible to provide a variety of high-quality services such as HDTV in a limited band. It has the advantage of being.

However, despite the advantages of the DVB-T2 system, the OFDM system used in the DVB-T2 system has a problem in that a high peak to average power amplifier (PAPR) is caused due to multi-carrier modulation. That is, since the OFDM method transmits data using multiple carriers, the amplitude of the final OFDM signal is the sum of the amplitudes of each carrier, so the amplitude of the amplitude varies greatly, and if the phases of the respective carriers coincide, the final OFDM signal has a very large value. . Such a high PAPR signal is out of the linear operating range of a high power linear amplifier, and distortion is generated in the signal passing through the high power linear amplifier, thereby deteriorating the performance of the system.

Various methods have been proposed to solve the problem of this, PAPR of the OFDM system, and various PAPRs such as clipping technique, coding, SLM (Selected Mapping), PTS (Partial Transmit Sequence), TI (Tone Injection), etc. There are abatement techniques.

The TR scheme, which is one of the above-described PAPR reduction techniques, reserves L tones among N subcarriers, and the reserved L tones are used to reduce PAPR without transmitting data.

1 shows a frame structure of a general broadcast communication system. Several OFDM symbols constitute one frame, and the pilot structure shows a distributed structure in which pilot positions change for each OFDM symbol. Since these pilots are used for channel estimation, interference or distortion should not occur. However, when the above-described reserved tone is used, a problem occurs in that the reserved tone and the pilot collide in the frame structure of FIG. 1.

FIG. 2 shows a case in which a collision occurs between pilot and reserved tones when one of the conventional tone reservation schemes is used in the frame structure as shown in FIG. 1. That is, in the case of 201, the reserved tone does not collide with the pilot, but it can be seen that a collision occurs between the pilots of 202, 203, and 204 and the reserved tones.

While avoiding the collision between the pilot and the reserved tone, the need to insert the reserved tone has increased.

It is an object of the present invention to provide a transmitting apparatus, a receiving apparatus, and a control method for transmitting by inserting a reserved tone so as not to overlap a pilot insertion position in a frame start symbol, a data symbol, and a frame end symbol.

According to an embodiment for achieving the above object, a transmission device includes a frame generator that generates a frame including a frame start symbol, a data symbol, and a frame closing symbol, and the frame starts. A pilot and reserved tone insertion unit inserting a pilot into a symbol, the data symbol, and the frame end symbol, and inserting a reserved tone so as not to overlap with the pilot insertion position, and the frame into which the pilot and reserved tones are inserted It includes a transmitter for transmitting.

Here, the pilot and reserved tone insertion unit inserts the pilot into the data symbol according to a preset first arrangement pattern, inserts the reserved tone so as not to overlap with the insertion position of the pilot, and inserts the reserved tone into a preset second arrangement pattern. Accordingly, the pilot may be inserted into the frame start symbol and the frame end symbol, and the reserved tone may be inserted so as not to overlap with the pilot insertion position.

In addition, the preset second arrangement pattern may be determined based on the preset first arrangement pattern.

In addition, the pilot and reserved tone inserting unit inserts a first reserved tone based on the arrangement pattern of the pilot inserted in the data symbol, and is additionally shifted from the insertion position of the first reserved tone by a preset value. A second reserved tone can be inserted.

In addition, reserved tones inserted in the frame start symbol and frame end symbol may be inserted at positions defined in Table 1.

In addition, the reserved tone inserted in the data symbol may be inserted at a position defined in Table 4.

In addition, the pilot may be inserted at a position defined in Table 6.

Meanwhile, an IFFT unit that performs an inverse Fourier (IFFT) operation on the frame start symbol, the data symbol, and the frame end symbol into which the pilot and reserved tones are inserted, and outputs a parallel signal output from the IFFT unit as a serial signal. It may further include a parallel/serial conversion unit for converting and outputting, and a PAPR reduction unit for reducing an average power-to-maximum power ratio (PAPR) based on the pilot and reserved tones.

Here, the PAPR reduction unit may calculate a reduction amount of the average power-to-maximum power ratio based on the pilot and the reserved tone, and output the serial signal by summing the calculated average power-to-maximum power ratio reduction amount.

Meanwhile, the receiving apparatus according to an embodiment of the present invention performs channel estimation based on the pilot and a receiving unit receiving a frame including a frame start symbol, a data symbol, and a frame end symbol into which a pilot and a reserved tone are inserted, and And a signal processor configured to detect data by processing the frame start symbol, the data symbol, and the frame end symbol in consideration of the position of the reserved tone, and the reserved tone is inserted so as not to overlap with the insertion position of the pilot.

Here, the reserved tones inserted in the frame start symbol and the frame end symbol are inserted at positions defined in Table 1.

In addition, the reserved tone inserted in the data symbol is inserted at the position defined in Table 4.

In addition, the pilot is inserted at the position defined in Table 6.

Meanwhile, a method of controlling a transmission device according to an embodiment of the present invention includes generating a frame including a frame start symbol, a data symbol, and a frame closing symbol, and the frame start symbol , Inserting a pilot into the data symbol and the frame end symbol, inserting a reserved tone so as not to overlap with an insertion position of the pilot, and transmitting the frame into which the pilot and reserved tone are inserted. can do.

Here, the step of inserting the reserved tone includes inserting the pilot into the data symbol according to a preset first arrangement pattern, inserting the reserved tone so as not to overlap with the insertion position of the pilot, and a preset second arrangement pattern Accordingly, the pilot may be inserted into the frame start symbol and the frame end symbol, and the reserved tone may be inserted so as not to overlap with the pilot insertion position.

In addition, the preset second arrangement pattern is determined based on the preset first arrangement pattern.

In addition, the step of inserting the reserved tone may include inserting a first reserved tone based on an arrangement pattern of the pilot inserted in the data symbol, and at a position shifted by a preset value from the insertion position of the first reserved tone. Additionally, a second reserved tone can be inserted.

In addition, reserved tones inserted in the frame start symbol and frame end symbol may be inserted at positions defined in Table 1.

In addition, the reserved tone inserted in the data symbol may be inserted at a position defined in Table 4.

In addition, the pilot may be inserted at a position defined in Table 6.

On the other hand, the control method of a transmitting apparatus according to an embodiment of the present invention comprises the steps of performing an inverse Fourier (IFFT) operation and outputting the frame start symbol, the data symbol, and the frame end symbol into which the pilot and reserved tones are inserted. And converting and outputting the parallel signal output by performing the inverse Fourier operation into a serial signal, and reducing an average power-to-maximum power ratio (PAPR) based on the pilot and reserved tones.

Here, the step of reducing the average power-to-maximum power ratio includes calculating a reduction amount of the average power-to-maximum power ratio based on the pilot and the reserved tone, and summing the calculated average power-to-maximum power ratio reduction amount to the serial signal. Can be printed.

Meanwhile, a method of controlling a reception apparatus according to an embodiment of the present invention includes receiving a frame including a frame start symbol, a data symbol, and a frame end symbol into which a pilot and a reserved tone are inserted, and channel estimation based on the pilot. And detecting data by processing the frame start symbol, the data symbol, and the frame end symbol in consideration of the position of the reserved tone, and the reserved tone is inserted so as not to overlap with the insertion position of the pilot. .

Here, the reserved tones inserted in the frame start symbol and the frame end symbol may be inserted at positions defined in Table 1.

In addition, the reserved tone inserted in the data symbol may be inserted at a position defined in Table 4.

In addition, the pilot may be inserted at a position defined in Table 6.

According to various embodiments of the present invention as described above, it is possible to insert a reserved tone while avoiding collision between a pilot and a reserved tone, and it is possible to reduce the PAPR based on the inserted pilot and the reserved tone.

1 and 2 are diagrams for explaining the prior art.
3 is a block diagram showing the configuration of a transmission device according to an embodiment of the present invention.
4 is a view for explaining the structure of a frame according to an embodiment of the present invention.
5 is a diagram illustrating positions of distributed pilots inserted into a frame start symbol, a data symbol, and a frame end symbol according to an embodiment of the present invention.
6 is a diagram illustrating a frame structure inserted so that distributed pilots and reserved tones do not collide with each other according to an embodiment of the present invention.
7 is a diagram illustrating an arrangement pattern of distributed pilots arranged to be shifted by a preset value according to an embodiment of the present invention.
8 is a block diagram showing a detailed configuration of a transmission device according to an embodiment of the present invention.
9 is a diagram showing a detailed configuration of a PAPR reduction unit according to an embodiment of the present invention.
10 is a block diagram showing the configuration of a receiving device according to an embodiment of the present invention.
11 is a block diagram showing a detailed configuration of a signal processing unit according to an embodiment of the present invention.
12 is a flowchart illustrating a method of controlling a transmission device according to an embodiment of the present invention.
13 is a flowchart illustrating a method of controlling a reception device according to an embodiment of the present invention.

Hereinafter, the present invention will be described in more detail with reference to the drawings. In addition, in describing the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. In addition, terms to be described later are terms defined in consideration of functions in the present invention, which may vary according to the intention or custom of users or operators. Therefore, the definition should be made based on the contents throughout the present specification.

The pilot structure of FIG. 2 is composed of continuous pilots maintained over several OFDM symbols and distributed pilots existing in one OFDM symbol and distributed evenly in the frequency domain. In this frame structure, since the positions of the pilots are different for each OFDM symbol, the positions of the reserved tones must also be different. Therefore, each OFDM symbol must have a different reserved tone.

However, since each OFDM symbol has different reserved tones, impulse waveforms generated as reserved tones also have different signals. Accordingly, in the OFDM system, information on all impulse waveforms must be stored in a memory, and accordingly, the memory size increases.

In the present invention, each OFDM symbol does not have different reserved tones, and proposes a method of applying to a frame using one reserved tone. Looking at the structure of the distributed pilot in FIG. 2, it can be seen that each OFDM symbol moves at a certain interval. Using this characteristic, the position of the reserved tone is also moved at the same interval as the distributed pilot, thereby avoiding collision between the reserved tone and the distributed pilot. I can.

3 is a block diagram showing the configuration of a transmission device according to an embodiment of the present invention.

Referring to FIG. 3, the transmission device 300 includes a frame generation unit 310, a pilot and reserved tone insertion unit 320, and a transmission unit 330.

The frame generator 310 may generate a frame including a frame start symbol, a data symbol, and a frame closing symbol.

A frame according to an embodiment of the present invention is a frame structure of an ATSC 3.0 system. Specifically, it will be described with reference to FIG. 4.

4 is a diagram illustrating a structure of a frame according to an embodiment of the present invention.

Referring to FIG. 4, one frame 400 includes one preamble symbol 440, one frame start symbol 410, a plurality of data symbols 420, and one frame end symbol 430.

Here, the frame 400 may correspond to a frame used in the DVB-T2 scheme, and accordingly, a T2 frame structure will be described in detail.

One T2 frame is composed of a P1 preamble symbol indicating the start position of the frame, a P2 preamble symbol transmitting an L1 signal, and data symbols transmitting a broadcast signal.

Specifically, the P1 preamble symbol is located at the first part of the T2 frame and may be used to detect the start point of the T2 frame. In addition, the P1 preamble symbol uses a 1K FFT size and is a signal in the form of a guard interval. In addition, the P1 preamble symbol in the frequency domain uses 384 subcarriers out of 853 subcarriers among 1K FFTs, and can transmit 7 bits of information.

The preamble symbol 440 according to an embodiment of the present invention corresponds to the above-described P1 preamble symbol and P2 preamble symbol, and may be used to perform a synchronization function by indicating a start position of a frame. In addition, by transmitting an L1 signal, It can be used to detect data.

The frame start symbol 410 indicates the start point of the data symbol 420, and positions of pilots and reserved tones inserted in the frame start symbol 410 and the data symbol 420 are different from each other. This will be described later.

In addition, the frame end symbol 430 indicates the end point of the data symbol 420, and the positions of the pilot and reserved tones inserted in the frame end symbol 430 and the data symbol 420 are different from each other, which will be described later. do.

The pilot and reserved tone insertion unit 320 may insert a pilot into a frame start symbol, a data symbol, and a frame end symbol, and insert a reserved tone so as not to overlap with an insertion position of the pilot.

Here, the pilot and reserved tone insertion unit 320 may correspond to the pilot insertion unit of the DVB-T2 transmission system. The DVB-T2 transmission system may include an input processor (not shown), a BICM encoder (not shown), a frame builder (not shown), and a modulator (not shown).

Each configuration will be outlined in that it is the same as the content defined in DVB-T2, one of the digital broadcasting standards. For more information, please refer to "Digital Video Broadcasting (DVB); Frame structure channel coding and modulation for a second generation digital terrestrial television broadcasting system (DVB-T2)".

An input processor (not shown) may process a signal in a baseband frame format to be generated from an input broadcast signal.

A BICM encoder (not shown) performs encoding by determining an FEC coding rate and a constellation order according to an area (Fixed PHY Frame or Mobile PHY Frame) to which data to be serviced is to be transmitted. The signaling information on the data to be serviced may be encoded through a separate BICM encoder (not shown) or encoded by sharing the BICM encoder (not shown) with the data to be serviced depending on the implementation.

A frame builder (not shown) and a modulator (not shown) determine an OFDM parameter for a signaling region and an OFDM parameter for a region in which data to be serviced is to be transmitted, configure a frame, and generate a frame by adding a sync region. Further, modulation for modulating the generated frame into an RF signal is performed, and the RF signal is transmitted to a receiver.

Here, the T2 frame structure may include a data subcarrier for transmitting a signal modulated with a broadcast signal, a pilot for channel estimation, and reserved tones for reducing a peak to average power ratio (PAPR).

The pilot and reserved tone may be performed by a pilot insertion unit (not shown) of a modulator (not shown). Specifically, the pilot insertion unit (not shown) inserts a pilot of a predetermined pilot pattern at a corresponding position in the frame and outputs it to the OFDM generator (not shown). Various cells in the OFDM frame are modulated with reference information of a transmitted value known to the receiving unit. The cell containing the reference information is transmitted at a boosted power level. Information transmitted from these cells is a scattered pilot cell, a continuous pilot cell, an edge pilot cell, a P2 pilot cell, or a frame-closing pilot. It is a cell. The value of the pilot information is obtained from a reference sequence, which is a series of values.

In addition, the pilot and reserved tone insertion unit 320 according to an embodiment of the present invention may correspond to a pilot insertion unit (not shown) of a modulator (not shown).

In addition, the transmitter 330 may transmit a frame into which a pilot and a reserved tone are inserted.

Meanwhile, the pilot and reserved tone insertion unit 320 inserts a pilot for channel estimation and synchronization. In general, the pilot is a scattered pilot, a continuous pilot, as well as a P2 pilot included only in the P2 symbol. , And the frame end pilot of the frame closing symbol.

The distributed pilot is a pilot that is constantly inserted not only in the time but also in the frequency direction, and is mainly used for channel estimation and equalization. Although the distributed pilot pattern of the existing DVB-T is constantly inserted regardless of the FFT size or the guard interval, DVB-T2 flexibly applies eight patterns from PP1 to PP8 according to the FFT and the guard interval. These patterns are designed according to the maximum guard interval length (1/Dx) and channel Doppler limit (1/Dy), and since the pilot size for each pattern is 2.5~7.4dB higher than that of general data, sufficient channel estimation performance is achieved. While maintaining, it has the advantage of reducing the overhead caused by pilot insertion.

In addition, the continuous pilot pattern is constantly inserted in the time direction, and the number of pilots inserted is relatively small compared to the DVB-T, but the size of the pilot is about 2.5 to 8.5 dB depending on the FFT compared to the general data. In the 8K, 16K, and 32K modes, the overhead due to pilot insertion was reduced from 2.5% to 0.7% without deterioration in frequency synchronization and CPE detection performance, and the overhead was further reduced by sharing the positions of some continuous pilots and distributed pilots.

On the other hand, according to an embodiment of the present invention, the continuous pilot means a pilot continuously inserted without changing positions in the frame start symbol 410, the data symbol 420, and the frame end symbol 430, and a distributed pilot Denotes a pilot that is inserted in the frame start symbol 410, the data symbol 420, and the frame end symbol 430 by changing positions according to a predetermined pattern.

5 is a diagram illustrating positions of distributed pilots inserted into a frame start symbol, a data symbol, and a frame end symbol according to an embodiment of the present invention.

For example, looking at the case where the pilot pattern is P4,4, the distributed pilot inserted in the data symbol 420 is set to be arranged in a pattern of Dx=4 and Dy=4. This means that the distributed pilots inserted into the data symbol 420 are shifted at equal intervals by a size of 4 and are arranged in 4 columns.

In addition, the distributed pilot inserted into the frame starting symbol (FSS) 410 and the frame closing symbol (FCS) 430 is set to be arranged in a pattern of Dx=4 and Dy=1. . This means that distributed pilots inserted into the frame start symbol 410 and the frame end symbol 430 are arranged at equal intervals as much as 4 and arranged in one column.

That is, the arrangement pattern of the distributed pilot inserted into the data symbol 420 and the arrangement pattern of the distributed pilot inserted into the frame start symbol 410 and the frame end symbol 430 are different from each other.

Accordingly, the arrangement pattern of the reserved tone inserted into the data symbol 420 and the arrangement pattern of the reserved tone inserted into the frame start symbol 410 and the frame end symbol 430 are also different from each other.

In addition, the pilot and reserved tone insertion unit 320 inserts a pilot into the data symbol 420 according to a preset first arrangement pattern, inserts a reserved tone so as not to overlap with the insertion position of the pilot, and inserts a preset second arrangement pattern. According to this, a pilot may be inserted into the frame start symbol 410 and the frame end symbol 430, and a reserved tone may be inserted so as not to overlap with the insertion position of the pilot.

Here, the preset second arrangement pattern is determined based on the preset first arrangement pattern. That is, the preset first arrangement pattern refers to an arrangement pattern of distributed pilots inserted into the data symbol 420, and the pre-set second arrangement pattern is variance inserted into the frame start symbol 410 and the frame end symbol 430. It may mean a pilot arrangement pattern.

Further, the preset first and second preset patterns may be arrangement patterns including not only the arrangement pattern of the distributed pilot but also the arrangement pattern of the continuous pilot. This is because the reserved tones inserted in the frame start symbol 410, the data symbol 420, and the frame end symbol 430 must not overlap not only the distributed pilot but also the insertion position of the continuous pilot.

That is, the pilot and reserved tone insertion unit 320 may insert the reserved tone into the data symbol 420 so as not to overlap with the distributed pilot and continuous pilot inserted in the data symbol 420 according to a preset first arrangement pattern, A reserved tone is inserted into the frame start symbol 410 and the frame end symbol 430 so as not to overlap with the distributed pilot and continuous pilot inserted in the frame start symbol 410 and the frame end symbol 430 according to a preset second arrangement pattern. can do.

When the first arrangement pattern and the second arrangement pattern include only the arrangement pattern of the distributed pilot, a reserved tone may be inserted in consideration of the arrangement pattern of the continuous pilot, and the first arrangement pattern and the second arrangement pattern are arrangement of the distributed pilot. In the case of including the pattern and the arrangement pattern of the continuous pilot, the reserved tone may be inserted in consideration of only the first arrangement pattern and the second arrangement pattern.

6 is a diagram for explaining a frame structure inserted so that distributed pilots and reserved tones do not collide with each other according to an embodiment of the present invention.

By setting the position of the reserved tone designed in the OFDM symbol equal to the shift interval of the distributed pilot, collisions with each other are avoided, and as mentioned previously, the problem of increasing memory that occurs when one reserved tone is reused is solved. I can.

When the position where the reserved tone is inserted is circularly shifted in the frequency domain, the impulse waveform generated by the reserved tone does not change the magnitude of the complex value, but only the phase. Since the phase change varies as much as the separation interval, if only the initial phase information is known, the phase change according to the separation interval can be known. Accordingly, a method of inserting a reserved tone in consideration of a pilot arrangement pattern according to an embodiment of the present invention can be applied to all OFDM symbols in a frame.

Specifically, referring to FIG. 6, the arrangement patterns of pilots inserted into the frame start symbol 610 and the frame end symbol 630 are the same, and the arrangement of reserved tones inserted so as not to overlap in consideration of the arrangement pattern of these pilots. The patterns are also the same.

On the other hand, the pilot arrangement pattern inserted into the data symbol 620 is different from the pilot arrangement pattern inserted into the frame start symbol 610 and the frame end symbol 630, and is inserted so as not to overlap in consideration of the arrangement pattern of these pilots. The arrangement pattern of the reserved tones to be used is also different from the arrangement pattern of the reserved tones inserted in the frame start symbol 610 and the frame end symbol 630.

In addition, it can be seen that the pilot and reserved tones inserted in all the symbols 610, 620, and 630 shown in FIG. 6 do not overlap with each other.

Meanwhile, a pilot arrangement pattern inserted into the frame start symbol 610 and the frame end symbol 630 may be determined based on a pilot arrangement pattern inserted into the data symbol 620.

For example, if the pilot arrangement pattern inserted into the data symbol 620 is Dx=4 and Dy=4, the pilot arrangement pattern inserted into the frame start symbol 610 and the frame end symbol 630 is Dx=4. , Dy = 1, which means an arrangement pattern arranged in one row while maintaining a shift interval of an inserted pilot.

That is, pilots inserted into the frame start symbol 610 and the frame end symbol 630 are disposed at all subcarrier positions corresponding to the pilot arrangement pattern inserted into the data symbol 620.

Meanwhile, the pilot and reserved tone insertion unit 320 inserts the first reserved tone based on the arrangement pattern of the pilot inserted in the data symbol 620, and a position shifted by a preset value from the insertion position of the first reserved tone. In addition, a second reserved tone may be inserted.

Specifically, as described above, the pilot and reserved tone insertion unit 320 may reserve the first reserved tone so as not to overlap with the position of the pilot inserted in the data symbol 620. Here, the inserted pilot is a concept including both a distributed pilot and a continuous pilot. Accordingly, the pilot and reserved tone insertion unit 320 may reserve the first reserved tone so as not to overlap the positions of the distributed pilot inserted in the data symbol 620 and the continuous pilot.

In addition, the pilot and reserved tone insertion unit 320 may additionally reserve the second reserved tone in consideration of an arrangement pattern of the distributed pilot. Specifically, the pilot and reserved tone insertion unit 320 may reserve the second reserved tone in consideration of the amount by which the distributed pilot is shifted. This will be described in detail with reference to FIG. 7.

7 is a diagram illustrating an arrangement pattern of distributed pilots arranged to be shifted by a preset value according to an embodiment of the present invention.

Referring to FIG. 7, it can be seen that when a distributed pilot is located at 20 subcarrier intervals, the number of OFDM symbols increases and cyclically moves at 4 subcarrier intervals.

Accordingly, the pilot and reserved tone insertion unit 320 inserts the first reserved tone so as not to overlap with the distributed pilot inserted in the second column shown in FIG. 7, and the distributed pilot inserted in the first column shown in FIG. 7 is the second Since it is shifted by 4 subcarrier intervals based on the distributed pilot inserted in the column, the second reserved tone can be inserted at a position shifted by 4 subcarrier intervals from the insertion position of the first reserved tone inserted in the second column. .

Equation 1 below is an equation representing the insertion position of the inserted reserved tone in consideration of the above-described distributed pilot arrangement pattern.

Here, S ₀ represents the position of the reserved tone, and N _RT is Indicates the number of reserved tones.

Accordingly, the pilot and reserved tone insertion unit 320 considers the shifted value of the distributed pilot when only the insertion position of the first reserved tone is determined without having to calculate the insertion position of the reserved tone for all data symbols each time. Accordingly, since the insertion position of the second reserved tone can be determined, the amount of calculation can be reduced, and, as previously described, the amount of memory for storing the impulse signal corresponding to each reserved tone can be reduced.

Meanwhile, the reserved tone inserted into the frame start symbol 610 and the frame end symbol 630 may be inserted at positions defined in Table 1 below.

Table 1 is a table showing indexes indicating positions of reserved tones inserted into a frame start symbol (FSS) and a frame end symbol (FCS) according to an embodiment of the present invention. That is, the positions of the reserved tones shown in Table 1 are the frame start symbol 610 and the frame end symbol ( 630) is the position of the reserved tone.

Meanwhile, DVB-T2, a European broadcasting standard, considers various OFDM sizes, and includes 1K, 2K, 4K, 8K, 16K, and 32K modes as follows. Table 2 below shows the OFDM size, the number of data symbols, and the number of reserved tones.

1K mode 2K mode 4K mode 8K mode 16K mode 32K mode Number of subcarriers 1024 2048 4096 8192 16384 32766 Number of data symbols 853 1705 3409 6517 13833 27265 Reserved tonnage 9 18 36 72 144 288

That is, the number and insertion positions of reserved tones that can be inserted may vary according to the above-described mode. The distributed pilot may have a shape similar to that of FIG. 7 and may be inserted in various modifications according to the above-described mode. For example, unlike FIG. 7, distributed pilots may be inserted at intervals of 12 subcarriers. In addition, a reserved tone can be inserted so as not to overlap with the insertion position of the distributed pilot. Accordingly, the number and insertion positions of reserved tones that can be inserted for each mode are changed.

Like the reserved tones inserted differently for each mode of the DVB-T2 described above, the reserved tones inserted in the frame start symbol and the frame end symbol according to an embodiment of the present invention may be inserted differently for each mode.

The number of reserved tones inserted for each mode shown in Table 1 is summarized in Table 3 below.

8K mode 16K mode 32K mode Number of subcarriers 8192 16384 32766 Reserved tonnage 72 144 288

In addition, the index displayed for each mode indicates positions of reserved tones inserted in the frame start symbol 610 and the frame end symbol 630.

It can be seen that the positions of the reserved tones displayed for each mode are different.

Meanwhile, the reserved tone inserted in the data symbol may be inserted at a position defined in Table 4 below.

Table 4 is a table showing an index indicating a position of a reserved tone inserted in a data symbol according to an embodiment of the present invention. That is, the positions of the reserved tones shown in Table 4 are reserved tones inserted in the data symbol 620 designed in consideration of the insertion positions of distributed pilots and continuous pilots according to the modes in which the FFT size is 8K, 16K, and 32K for each mode. Is the location of.

Likewise, like the reserved tone inserted differently for each mode of the DVB-T2 described above, the reserved tone inserted into the data symbol according to an embodiment of the present invention may be inserted differently for each mode.

The number of reserved tones inserted for each mode shown in Table 4 is summarized in Table 5 below.

8K mode 16K mode 32K mode Number of subcarriers 8192 16384 32766 Reserved tonnage 72 144 288

In addition, the index displayed for each mode indicates the position of the reserved tone inserted in the data symbol 620. Likewise, the positions of the reserved tones displayed for each mode are different from each other.

Meanwhile, the pilot may be inserted at a position defined in Table 6 below.

Table 6 is a table showing indexes indicating insertion positions of continuous pilots according to modes in which FFT sizes are 8K, 16K, and 32K according to an embodiment of the present invention.

That is, the indexes indicating the positions of the reserved tones inserted in the frame start symbol 610, the frame end symbol 630, and the data symbol 620 shown in Tables 1 and 4 are the consecutive pilots defined in Table 6. It is designed not to overlap each other in consideration of the index indicating the insertion position and the insertion position of the distributed pilot, that is, the arrangement pattern.

8 is a block diagram showing a detailed configuration of a transmission device according to an embodiment of the present invention.

Referring to FIG. 8, the transmission device 300 includes a frame generation unit 310, a pilot and reserved tone insertion unit 320, an IFFT unit 340, a parallel/serial conversion unit 350, and a PAPR reduction unit 360. And a transmission unit 330.

When the pilot and reserved tone insertion unit 320 is described in more detail, an input signal of N-L points and L reserved tone signals may be input to the pilot and reserved tone insertion unit 320. Here, data is not transmitted to the L reserved tones, and zeros are inserted.

The IFFT unit 340 may perform an inverse Fourier (IFFT) operation and output a frame start symbol, a data symbol, and a frame end symbol into which the pilot and reserved tones are inserted. Specifically, when the sum of the input signal at points N-L and L reserved tones, which is a parallel signal, is input to the IFFT unit 340, an IFFT operation may be performed.

The parallel/serial conversion unit 350 may convert a parallel signal output from the IFFT unit 340 into a serial signal and output it. Specifically, the parallel/serial converter 350 may output an output signal in a time domain by converting the parallel signal into a serial signal.

The PAPR reduction unit 360 may reduce an average power-to-maximum power ratio (PAPR) based on a pilot and a reserved tone.

Specifically, the PAPR reduction unit 360 may calculate a reduction amount of the average power-to-maximum power ratio based on the pilot and the reserved tone, and may output by summing the reduction amount of the average power-to-maximum power ratio calculated in the serial signal.

The PAPR reduction unit 360 may include a gradient algorithm unit (not shown), and may add a signal generated by the gradient algorithm unit (not shown) to the output signal output from the IFFT unit 340 and output it. . Here, the gradient algorithm unit (not shown) may reduce the average power-to-maximum power ratio of the output signal output from the IFFT unit 340 by using the impulse signal corresponding to the reserved tone.

Meanwhile, although not shown in FIG. 8, the transmission device 300 may further include a memory (not shown) and a control unit (not shown).

The memory (not shown) may store information on the number of reserved tones and the location of the reserved tones according to the OFDM size. The gradient algorithm unit (not shown) generates a signal in the form of an impulse using information stored in a memory, and the generated impulse signal is stored in a memory (not shown).

In addition, the memory (not shown) transmits information on the number of reserved tones and the location of the reserved tones to a control unit (not shown), and the control unit (not shown) does not collide with data and pilots according to the OFDM size and pilot location. Information on the number of reserved tones and the location of the reserved tones may be transmitted to the pilot and reserved tone insertion unit 320 so that the reserved tones are allocated.

Accordingly, the pilot and reserved tone insertion unit 320 may allocate and insert subcarriers so that the pilot and reserved tones do not collide with each other.

In addition, the control unit (not shown) may adjust the position shift of the reserved tone and the phase of the impulse signal by calculating the shift interval of the distributed pilot according to the OFDM symbol index. Even if the position of the reserved tone is cyclically moved, the magnitude of the impulse signal does not change, so the same PAPR reduction performance can be maintained. In addition, the shift interval may be calculated by the pilot and reserved tone insertion unit 320 instead of the control unit (not shown) and then sent to the control unit (not shown) to calculate the phase.

9 is a diagram showing a detailed configuration of a PAPR reduction unit according to an embodiment of the present invention.

9, the PAPR reduction unit 360 includes a P waveform generator 361, a peak detection unit 362, a position cycle moving unit 363, a phase rotation unit 364, a scaling unit 365, and a complex adder ( 366), a PAPR calculation unit 367 and a control unit 367 may be included.

The P waveform generator 361 may generate a P waveform having an impulse characteristic with L reserved tones, excluding an input signal of an NL point, which is a parallel signal among all N signals. Here, the P waveform repeats the trial of randomly selecting at least one reserved L tone among all signals, and among them, the power value is the highest among the _{remaining P 1} to P _{N - 1} values excluding the peak value _{of P 0} I chose a small case.

Meanwhile, the peak detector 362 may detect the maximum peak value of the input signal at points N-L.

Then, the position circulation moving unit 363 cyclically moves the position of the P waveform to the position of the detected maximum peak value.

The phase rotation unit 364 matches the phase of the cyclically shifted P waveform with the detected peak value on the complex plane.

In addition, the scaling unit 365 may scale the value of the P waveform so that the peak value of the signal output after the IFFT operation of the input signal at point N-L becomes less than or equal to a preset PAPR value.

The complex adder 366 converts the input signal of the NL point to a signal output after the IFFT operation and the calculated value to reduce the maximum peak value of the P waveform to a predetermined level or less, and the input signal of the NL point is a signal output after IFFT operation. It can be summed up and transmitted as an input value of the PAPR calculating unit 367.

The controller 368 may feed back the input PAPR calculation value to be equal to or less than a preset PAPR value. This repetition is repeated until the input PAPR calculation value becomes less than or equal to the preset PAPR value.

10 is a block diagram showing the configuration of a receiving device according to an embodiment of the present invention.

Referring to FIG. 10, the receiving device 1300 may include a receiving unit 1310 and a signal processing unit 1320.

The receiver 1310 may receive a frame including a frame start symbol, a data symbol, and a frame end symbol into which pilot and reserved tones are inserted.

The signal processor 1320 may perform channel estimation based on a pilot and detect data by signal-processing a frame start symbol, a data symbol, and a frame end symbol in consideration of the position of the reserved tone. Here, the reserved tone is inserted so as not to overlap with the insertion position of the pilot.

11 is a block diagram showing a detailed configuration of a signal processing unit of a reception device according to an embodiment of the present invention.

Referring to FIG. 11, the signal processing unit 1320 includes a parallel/serial conversion unit 1321, an FFT unit 1322, a data symbol detection unit 1323, a data demodulation unit 1324, a memory 1325, and a control unit 1326. It may include.

The parallel/serial conversion unit 1321 may convert the received signals in the input time in parallel and output them to the FFT unit 1332.

The FFT unit 1332 may Fourier transform the input signals to convert the signals into frequency signals, and transmit the converted signals to the data symbol detector 1323.

Here, the memory 1325 outputs the positions of the reserved tones inserted in the frame start symbol 610, the data symbol 620, and the frame end symbol 630 according to an embodiment of the present invention that have been previously stored, and outputs The position of the reserved tone is input to the control unit 1326.

The control unit 1326 adjusts the position of the inserted reserved tone according to the pilot position in the OFDM symbol received by the receiving unit 1310 so as not to collide with the pilot position, and outputs it to the data symbol detection unit 1323.

The data symbol detection unit 1323 extracts signals at positions other than the position of the reserved tone input from the control unit 1326 among the signals on the frequency input from the FFT unit 1322, that is, signals corresponding to the data symbols. Can be printed. Accordingly, the data symbol 620 extracted by the data symbol detection unit 1323 is input to the data demodulation unit 1324 to perform a data demodulation operation.

Meanwhile, the reserved tone inserted into the frame start symbol 610 and the frame end symbol 630 may be inserted at positions defined in Table 1.

In addition, the reserved tone inserted in the data symbol 620 may be inserted at a position defined in Table 4.

In addition, the pilot may be inserted at the position defined in Table 6.

12 is a flowchart illustrating a method of controlling a transmission device according to an embodiment of the present invention.

According to the control method of the transmission device illustrated in FIG. 12, a frame including a frame start symbol, a data symbol, and a frame closing symbol may be generated (S1510 ).

Subsequently, a pilot may be inserted into a frame start symbol, a data symbol, and a frame end symbol, and a reserved tone may be inserted so as not to overlap with the pilot insertion position (S1520).

Here, the step of inserting the reserved tone includes inserting the pilot into the data symbol according to the preset first arrangement pattern, inserting the reserved tone so as not to overlap with the pilot insertion position, and starting the frame according to the preset second arrangement pattern. And inserting a pilot into the frame end symbol, and inserting a reserved tone so as not to overlap with the pilot insertion position. The preset second placement pattern may be determined based on the preset first placement pattern.

In addition, the step of inserting the reserved tone includes inserting the first reserved tone based on the arrangement pattern of the pilot inserted in the data symbol, and additionally at the shift position by a preset value from the insertion position of the first reserved tone. Can be inserted.

In addition, a frame into which a pilot and a reserved tone are inserted may be transmitted (S1530).

Here, the reserved tones inserted in the frame start symbol and the frame end symbol may be inserted at positions defined in Table 1.

In addition, the reserved tone inserted in the data symbol may be inserted at the position defined in Table 4.

The pilot can be inserted at the position defined in Table 6.

On the other hand, the control method of the transmitting apparatus shown in FIG. 12 is a step of outputting a frame start symbol, a data symbol, and a frame end symbol into which a pilot and a reserved tone are inserted, by performing an inverse Fourier operation, and performing an inverse Fourier operation. It may further include converting the output parallel signal into a serial signal and outputting it, and reducing an average power-to-maximum power ratio (PAPR) based on the pilot and the reserved tone.

Here, in the step of reducing the average power-to-maximum power ratio, a reduction amount of the average power-to-maximum power ratio is calculated based on the pilot and the reserved tone, and the reduction amount of the average power-to-maximum power ratio calculated in the serial signal may be summed and output. .

13 is a flowchart illustrating a method of controlling a reception device according to an embodiment of the present invention.

According to the control method of the receiving apparatus illustrated in FIG. 13, a frame including a frame start symbol, a data symbol, and a frame end symbol into which pilot and reserved tones are inserted may be received (S1610).

Further, channel estimation is performed based on the pilot, and the frame start symbol, the data symbol, and the frame end symbol are signal-processed in consideration of the position of the reserved tone to detect data (S1620).

Here, the reserved tone is inserted so as not to overlap with the insertion position of the pilot.

In addition, reserved tones inserted in the frame start symbol and the frame end symbol may be inserted at positions defined in Table 1.

In addition, the reserved tone inserted in the data symbol may be inserted at a position defined in Table 4.

In addition, the pilot may be inserted at the position defined in Table 6.

Meanwhile, a plurality of frames received by the reception device 200 are transmitted to the DVB-T2 transmission system, and a signaling region of the frame may be a region transmitting L1 signaling.

As described above, according to various embodiments of the present disclosure, by reconstructing information included in the signaling area, information included in the signaling area increases, and accordingly, data can be variously processed.

Meanwhile, a non-transitory computer readable medium in which a program for sequentially performing the control method according to the present invention is stored may be provided.

For example, generating a frame including a frame start symbol, a data symbol, and a frame end symbol, inserting a pilot into the frame start symbol, data symbol, and frame end symbol, and inserting a reserved tone so as not to overlap with the insertion position of the pilot. And a non-transitory computer readable medium in which a program for performing a step of transmitting a frame in which a pilot and a reserved tone are inserted is stored.

In addition, as an example, receiving a frame including a frame start symbol, a data symbol, and a frame end symbol into which a pilot and a reserved tone are inserted, and performing channel estimation based on the pilot, and starting the frame in consideration of the position of the reserved tone. A non-transitory computer readable medium in which a program for detecting data by signal processing a symbol, a data symbol, and a frame end symbol may be provided.

The non-transitory readable medium refers to a medium that stores data semi-permanently and can be read by a device, rather than a medium that stores data for a short moment, such as a register, a cache, and a memory. Specifically, the above-described various applications or programs may be provided by being stored in a non-transitory readable medium such as a CD, DVD, hard disk, Blu-ray disk, USB, memory card, ROM, or the like.

In addition, although a bus is not shown in the above-described block diagram showing the transmitting device and the receiving device, communication between components in the transmitting device and the receiving device may be performed through a bus. In addition, each device may further include a processor such as a CPU or a microprocessor that performs the various steps described above.

In addition, although the preferred embodiments of the present invention have been illustrated and described above, the present invention is not limited to the specific embodiments described above, and the technical field to which the present invention belongs without departing from the gist of the present invention claimed in the claims. In addition, various modifications are possible by those of ordinary skill in the art, and these modifications should not be understood individually from the technical spirit or prospect of the present invention.

300: transmission device 310: frame generation unit
320: pilot and reserved tone insertion unit 330: transmission unit
1300: receiving device 1310: receiving unit
1320: signal processing unit

Claims (9)

In the transmission method,
Generating a frame for transmitting data;
Inserting a pilot into the frame including data symbols and at least one boundary symbol; And
Acquiring a position of a tone in the data symbols and at least one boundary symbol, and performing a peak to average power ratio (PAPR) reduction based on the position of the tone; and
The at least one boundary symbol includes at least one of a symbol positioned before a first data symbol among the data symbols and a symbol positioned after a last data symbol among the data symbols,
The inserting may include inserting a pilot into the at least one boundary symbol based on a first pattern, and inserting a pilot into the data symbols based on a second pattern,
Wherein the pilot is not inserted at the position of the tone in the at least one boundary symbol and the data symbols. The method of claim 1,
The inserting step,
Inserting a pilot and a tone into the at least one boundary symbol and the data symbols,
The transmission method, wherein the position of the tone in the at least one boundary symbol and the data symbols does not overlap with the position of the pilot. The method of claim 1,
The inserting step,
Inserting a pilot into the data symbols based on the second pattern, inserting a tone into the data symbols so as not to overlap with the position of the pilot,
And inserting a pilot into the at least one boundary symbol based on the first pattern, and inserting a tone into the at least one boundary symbol so as not to overlap with a position of the pilot. The method of claim 1,
The transmission method, wherein the first pattern is determined based on the second pattern. The method of claim 1,
In the at least one boundary symbol, a tone is inserted at a position as shown in the following table according to a mode in which a Fast Fourier Transform (FFT) size is 8K, 16K, or 32K.

The method of claim 1,
Tones in the data symbols are inserted at positions as shown in the following table according to modes in which the FFT (Fast Fourier Transform) size is 8K, 16K, and 32K, a transmission method:

The method of claim 1,
The pilot is inserted in a position as shown in the following table in the frame according to a mode in which the FFT (Fast Fourier Transform) size is 8K, 16K, or 32K, transmission method:

The method of claim 1,
Performing an Inverse Fast Fourier Transform (IFFT) operation on the data symbols into which the pilot and tone are inserted and the at least one boundary symbol; And
Converting the parallel signal based on the IFFT operation into a serial signal; further comprising,
The performing step is to perform PAPR reduction based on the pilot and the tone. The method of claim 8,
The performing step,
And calculating a reduction amount of PAPR based on the pilot and the tone, summing the calculated reduction amount of PAPR to the serial signal and outputting the sum.

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