KR20150035366A - Transmitting apparatus and receiving apparatus and controlling method thereof - Google Patents

Abstract

A transmitting apparatus is provided. The transmitting apparatus includes: an input processor configured to process a plurality of input streams to generate a plurality of base band frames; a bit interleaved and coded modulation (BICM) processor configured to perform forward error correction (FEC) coding, constellation mapping, and interleaving on the plurality of baseband frames; a symbol generator configured to add signaling data to the plurality of baseband frames output from the BICM processor to generate an orthogonal frequency division multiplexing (OFDM) symbol; and a transmitter configured to select at least one of a plurality of pilot patterns based on a fast Fourier transform (FFT) size and a guard interval fraction, insert a pilot in the OFDM symbol according to the selected pilot pattern, and transmit a stream including the pilot-inserted OFDM symbol. Thus, a data transmission rate is increased and accurate channel estimation is performed, through inserting different pilots according to different FFT sizes and guard interval fractions.

Description

TECHNICAL FIELD [0001] The present invention relates to a transmitting apparatus, a receiving apparatus,

BACKGROUND OF THE INVENTION 1. Field of the Invention 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, broadcasting communication services are becoming multifunctional and broadband high quality. Particularly, with the development of electronic technology, the spread of mobile broadcasting devices such as high-definition digital TVs and high-end smartphones is increasing, and accordingly, there is a growing demand for various receiving methods and various services for broadcasting services.

In accordance with this demand, a broadcasting communication standard such as DVB-T2 (Digital Video Broadcasting Second Generation Terrestrial) has been developed as an example. DVB-T2 is a second-generation European terrestrial digital broadcasting standard that improves the performance of DVB-T, which is being adopted as a standard in more than 35 countries around the world including Europe. DVB- -T2 adopts the latest technologies such as LDPC (Low Density Parity Check) code and 256QAM modulation method to realize transmission capacity increase and high bandwidth efficiency, and thus it is possible to provide various high quality services such as HDTV in a limited bandwidth It has the advantage of being.

On the other hand, DVB-T2 uses a guard interval period to prevent interference between adjacent signals. This guard interval period can be defined differently depending on the FFT size, and accordingly, the inserted pilot pattern can be changed.

Accordingly, there has been a need to newly define a guard interval period that is set differently according to the FFT size and a pilot pattern that is determined according to the guard interval period.

It is an object of the present invention to provide a transmitting apparatus, a receiving apparatus, and a receiving apparatus for transmitting and receiving a pilot in an OFDM symbol according to a pilot pattern determined based on an FFT size and a guard interval period. And a control method.

According to an aspect of the present invention, there is provided a transmission apparatus including an input processor unit for dividing a plurality of input streams into a plurality of baseband frames, A BICM (Bit Interleaved and Coded Modulation) unit for performing constellation mapping and interleaving and outputting a signal, a structure unit for generating OFDM symbols by adding signaling data to a plurality of baseband frames output from the BICM unit, Selecting at least one of a plurality of pilot patterns based on a guard interval interval (Guard Interval Fraction), inserting a pilot into the OFDM symbol according to the selected pilot pattern, And a transmitter for transmitting the stream.

Here, the transmitter may include a spectrum shaping unit for filtering a signal corresponding to the OFDM symbol.

In addition, the spectrum forming unit may reduce a length of a filtering interval of a signal corresponding to the OFDM symbol, and increase a degree of attenuation of the signal size to generate a predetermined type of signal.

Also, the guard interval interval is defined as shown in Table 1 according to the modes in which the FFT sizes are 8K, 16K, and 32K.

Also, the plurality of pilot patterns are defined as shown in Table 3 based on the FFT size and the guard interval fractions in a single input single output (SISO) mode.

Also, the plurality of pilot patterns are defined as shown in Table 4 below based on the FFT size and the guard interval fractions in a multiple input single output (MISO) mode.

A receiving apparatus according to an embodiment of the present invention includes a pilot stream inserted in the OFDM symbol based on at least one of a plurality of pilot patterns set based on an OFDM symbol, an FFT size, and a guard interval interval (Guard Interval Fraction) Determining a pilot pattern used for the OFDM symbol from among the plurality of pilot patterns based on signaling information of the stream and a storage unit for storing information on the plurality of pilot patterns, And a signal processor for performing channel estimation using the detected pilot and signal processing the OFDM symbol to detect data.

Here, the signal corresponding to the OFDM symbol is filtered so as to be converted into a predetermined type of signal.

Also, the guard interval interval is defined as shown in Table 1 according to the modes in which the FFT sizes are 8K, 16K, and 32K.

Also, the plurality of pilot patterns are defined as shown in Table 3 based on the FFT size and the guard interval fractions in a single input single output (SISO) mode.

Also, the plurality of pilot patterns are defined as shown in Table 4 below based on the FFT size and the guard interval fractions in a multiple input single output (MISO) mode.

Meanwhile, a control method of a transmitting apparatus according to an embodiment of the present invention includes a step of dividing a plurality of input streams into a plurality of baseband frames, forward error coding (CSI) Mapping and interleaving, adding signaling data to the interleaved baseband frames to generate OFDM symbols, and generating a plurality of pilot patterns based on the FFT size and guard interval fractions (Guard Interval Fraction) And inserting a pilot in the OFDM symbol according to the selected pilot pattern, and transmitting a stream including the OFDM symbol in which the pilot is inserted.

Here, the transmitting step includes a spectrum shaping step of filtering a signal corresponding to the OFDM symbol.

Also, the spectrum forming step generates a predetermined type of signal by increasing the amount of attenuation of the signal while decreasing the length of the filtering interval of the signal corresponding to the OFDM symbol.

The guard interval period is defined as shown in Table 1 according to the modes in which the FFT sizes are 8K, 16K, and 32K.

Also, the plurality of pilot patterns are defined as shown in Table 3 based on the FFT size and the guard interval fractions in a single input single output (SISO) mode.

Also, the plurality of pilot patterns are defined as shown in Table 4 below based on the FFT size and the guard interval fractions in a multiple input single output (MISO) mode.

Meanwhile, a control method of a receiving apparatus according to an embodiment of the present invention is a control method of a receiving apparatus inserted in the OFDM symbol based on at least one of a plurality of pilot patterns set based on an OFDM symbol, an FFT size, and a guard interval interval Determining a pilot pattern used for the OFDM symbol among a plurality of previously stored pilot patterns based on the signaling information of the stream, detecting the pilot according to the determined pilot pattern, and Performing channel estimation using the detected pilot, and signal processing the OFDM symbol to detect data.

Here, the signal corresponding to the OFDM symbol is filtered so as to be converted into a predetermined type of signal.

As described above, according to various embodiments of the present invention, by inserting pilots differently according to different FFT sizes and guard interval intervals, it is possible to increase data rate and perform accurate channel estimation.

1 is a block diagram illustrating a configuration of a transmitting apparatus according to an embodiment of the present invention.
2 is a block diagram illustrating a configuration of a DVB-T2 on which the present invention is based.
3 is a block diagram illustrating a configuration for generating signaling information according to an embodiment of the present invention.
4 to 6 are views for explaining a unit structure of a transmission frame according to an embodiment of the present invention.
7 is a block diagram showing a detailed configuration of a transmitting unit according to an embodiment of the present invention.
8 is a diagram for explaining a process of spectrum formation and signal distortion according to an embodiment of the present invention.
9 is a diagram illustrating a spectrally formed signal in accordance with an embodiment of the present invention.
10 is a block diagram showing the configuration of a receiving apparatus according to an embodiment of the present invention.
11 is a block diagram showing the configuration of a receiving apparatus according to another embodiment of the present invention.
12 is a block diagram specifically illustrating a signal processing unit according to an embodiment of the present invention.
13 is a block diagram illustrating the configuration of a signaling processing unit according to an embodiment of the present invention.
14 is a flowchart illustrating a method of controlling a transmitting apparatus according to an embodiment of the present invention.
15 is a flowchart illustrating a method of controlling a receiving apparatus according to an embodiment of the present invention.

Various embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. The following terms are defined in consideration of the functions of the present invention, and these may be changed according to the intention of the user, the operator, or the like. Therefore, the definition should be based on the contents throughout this specification.

1 is a block diagram illustrating a configuration of a transmitting apparatus according to an embodiment of the present invention.

Referring to FIG. 1, a transmitting apparatus 100 includes an input processor 110, a bit interleaved and coded modulation (BICM) unit 120, a structure unit 130, and a transmission unit 140.

The input processor unit 110 divides a plurality of input streams into a plurality of baseband frames. Specifically, the input processor 110 outputs at least one PLP (Physical Layer Pipes) divided into a plurality of baseband frames. In one embodiment, the DVB-T2 system applies the PLP concept to enable various broadcasting services to be provided having different modulation schemes, channel coding rates, time, and cell interleaving lengths in one broadcast channel.

Here, the PLP independently refers to a signal path in which the PLP is processed independently. That is, each service (e.g., video, extended video, audio, data stream, etc.) can be transmitted and received through a plurality of RF channels, wherein PLP is a stream transmitted through such a path . In addition, the PLP may be located in slots that are distributed with a time interval on a plurality of RF channels, or may be distributed with a time interval on one RF channel. That is, one PLP can be distributed over one RF channel or multiple RF channels with a time interval.

The PLP structure is composed of an input mode A providing one PLP and an input mode B providing a plurality of PLPs. In particular, when the input mode B is supported, not only a specific service can be provided robustly, The time interleaving length can be increased to obtain a time diversity gain. In addition, when only a specific stream is received, the power of the receiver can be turned off during the remaining time, so that it can be used with low power, which is suitable for providing portable and mobile broadcast service.

In order to reduce the deterioration of transmission quality in the mobile communication transmission path, time diversity is performed so that when the same signal is transmitted several times at a predetermined time interval at the transmitting side, the receiving side synthesizes the received signals again to obtain a good transmission quality Technology.

In addition, information that can be commonly transmitted to a plurality of PLPs is included in one PLP to increase transmission efficiency. In this case, the PLP0 plays such a role. The PLP is referred to as a common PLP, The remaining PLPs may be used for data transmission, and such PLPs are referred to as data PLPs.

By using such a PLP, SDTV programs can be provided not only for receiving a home HDTV program, but also for carrying and traveling. In addition, it is possible not only to provide a variety of broadcasting services to viewers through a broadcasting station or a broadcasting contents provider, but also to provide a differentiated service capable of receiving broadcasts even in a poor reception area where viewing is difficult.

That is, the input processor unit 110 maps the data to be transmitted to at least one signal processing path to generate a frame, and signal processing is performed for each path. For example, the signal processing includes input stream synchronization, delay compensation, null packet deletion, CRC encoding, header insertion, coding, , Interleaving, and / or modulation. The frames processed by each path are generated as one transmission frame together with the signaling information, and the generated transmission frame is transmitted to a receiving device (not shown).

The bit interleaved and coded modulation (BICM) unit 120 performs forward error coding (CSI) on each of a plurality of baseband frames, performs constellation mapping and interleaving, and outputs the result.

Specifically, when a plurality of randomized baseband frames are input to the BICM unit 120, a plurality of baseband frames are encoded with a BCH code and then encoded with an LDPC code. The plurality of encoded baseband frames are interleaved by the bit interleaver and then the interleaved bits are mapped to constellation symbols according to QPSK, 16-QPSK, or higher QAM constellation sizes. The plurality of generated frames are referred to as FEC frames. Thereafter, the FEC frame is time interleaved.

The structure unit 130 adds signaling data to a plurality of baseband frames output from the BICM unit 120 to generate an OFDM symbol.

Specifically, the structure unit 130 schedules the time interleaved frame as a stream of data cells. The data cells are then interleaved on the frequency axis. An ATSC 3.0 frame is thus generated from the interleaved data cells on the frequency axis. Then, a physical layer signaling called L1 signaling is inserted as a preamble symbol of 8K size at the beginning of each ATSC 3.0 frame. This L1 signaling is used for fast synchronization of each frame.

The transmitter 140 selects at least one of the plurality of pilot patterns based on the FET size and the guard interval fraction, inserts the pilot in the OFDM symbol according to the selected pilot pattern, As shown in FIG.

The transmitter 140 inserts the continuous pilot and the scattered pilot together with the data cells in the ATSC 3.0 frame. Accordingly, the receiving apparatus (not shown) can perform channel estimation using the pilot, and can correct the frequency offset. The reserved tone for PAPR reduction can be selectively inserted.

Specifically, the various cells inserted in ATSC 3.0 are modulated with reference information known to the receiving device. The information transmitted by these cells is in the form of scatter, continuity, edge, frame-start or frame-closing pilot. The location and size of such pilots can be defined differently depending on the Single Input Single Output (SISO) transmission mode and the Multiple Input Multiple Output (MIMO) transmission mode to be described later. The values of the pilot can then be extracted from the reference sequence.

The pilots are modulated according to a reference sequence comprising information about the symbol number and the carrier index, where the reference sequence may be extracted from the symbol-level PRBS and the frame-level PN sequence. This reference sequence is then applied to all pilots of each symbol of the ATSC 3.0 frame.

That is, each value of the frame-level PN sequence can be applied to each OFDM symbol of the ATSC 3.0 frame, so that the length of the frame-level PN sequence becomes equal to the number of OFDM symbols of the ATSC 3.0 excluding the preamble symbol.

The maximum length of the PN sequence may vary depending on the FFT mode and the guard interval period as shown in Table 1 below.

That is, the maximum length of the PN sequence is 32 K, 16 K and 8 K in the FFT mode, and 2/512, 6/512, 12/512, 24/512, 36/512, 48/512, 57/512 , 72/512, and 96/512, respectively. Referring to Table 1, it can be seen that as the length of the inserted guard interval section increases, the maximum length of the PN sequence decreases. This is because the guard interval section is inserted to prevent interference with the adjacent signal, so that the area in which the PN sequence can be inserted is reduced.

Also, the guard interval period is defined according to the case where the FFT modes are 8K, 16K, and 32K as shown in Table 1, and can be inserted differently for each mode.

On the other hand, the reference information obtained from the reference sequence is transmitted by the scattered pilot inserted in all the symbols except for the frame start symbol, the frame closing symbol and the preamble symbol of the ATSC 3.0 frame. The arrangement positions of the scattered pilots are defined as shown in Table 2 below.

For example, P4,4 = _X 4 is D, _Y D = 4 to mean a pattern of scattered pilot is placed at the same intervals as the size of 16, means that are disposed four rows. For example, in the case of the distributed pilots inserted in the data symbols, if the data symbols are arranged at the same interval from the first column to the sixth column of the data symbol, in the second column of the data symbol, And are spaced apart from each other by a distance of four spaces from the scatter pilot inserted in the first column of the data symbol. Accordingly, it is possible to arrange them in four rows so as to have a difference of four spaces, and to arrange them at the same intervals as the size of 16 in each row by the size of 16.

As described above, the transmitter 140 can select at least one of a plurality of pilot patterns by combining the FFT size, the guard interval section selected in each FFT size, and the pilot allocation pattern. When the guard interval section is changed, The arrangement pattern of the first and second electrodes can be flexibly changed. That is, when the inserted guard interval section is reduced, the dispersion interval D _X can be increased.

A plurality of pilot patterns are defined as shown in Table 3 based on the FFT size in the SISO mode and the guard interval period selected in each FFT size.

It can be seen that as the length of the guard interval is longer for each FFT mode, the dispersion interval D _X decreases.

The plurality of pilot patterns are defined as shown in Table 4 based on the FFT size in the MISO mode and the guard interval period selected in each FFT size.

In the above Tables 3 and 4, the pilot allocation patterns of P4,4 and P16,4 in the 32K FFT mode of the SISO mode and the MOSO mode are excluded in consideration of the memory capacity of the receiving apparatus. However, it is of course possible to increase the memory capacity of the receiving apparatus, and to use the pilot arrangement patterns of P4,4 and P16,4 in the 32K FFT mode of the SISO mode and the MOSO mode.

Then, the transmitter 140 converts the pilot-inserted ATSC 3.0 frame into a signal on the time axis by performing an IFFT (Inverse FFT) operation. In order to avoid interference between symbols, a guard interval is inserted in each symbol, and spectrum shaping is performed between adjacent channels to ensure minimum interference. A detailed description thereof will be described later.

The transmitter 140 performs digital-to-analog conversion on the signal on the time axis to generate a baseband analog signal, and transmits the baseband analog signal.

2 is a block diagram illustrating a configuration of a DVB-T2 on which the present invention is based.

2, the DVB-T2 transmission system 1000 may include an input processor 1100, a BICM encoder 1200, a frame builder 1300, and a modulator 1400.

The configuration of the DVB-T2 transmission system 1000 is the same as that defined in DVB-T2, which is one of the European digital broadcasting standards. For details, refer to "Digital Video Broadcasting (DVB) Frame Structure Channel Coding and Modulation for a Second Generation Digital Terrestrial Television Broadcasting System (DVB-T2) ".

The BICM encoder 1200 determines an FEC coding rate and a constellation order according to a region (Fixed PHY Frame or Mobile PHY Frame) to which data to be transmitted is to be transmitted, and performs coding. The signaling information for the data to be served may be encoded through a separate BICM encoder (not shown) or may be encoded by sharing the BICM encoder 1200 with the data to be served.

The frame builder 1300 and the modulator 1400 determine an OFDM parameter for a signaling region and an OFDM parameter for an area to which data to be transmitted is to be transmitted to construct a frame and add a sink area to generate a frame. Then, modulation is performed to modulate the generated frame with the RF signal, and the RF signal is transmitted to the receiver.

3 is a block diagram illustrating a configuration for generating signaling information according to an embodiment of the present invention.

Referring to FIG. 3, an input processor 1100 and a BICM encoder 1200 are shown. The input processor 1100 may include a scheduler 1110. The BICM encoder 1200 includes an L1 signaling generator 1210, FEC encoders 1220-1 and 1220-2, a bit interleaver 1230-2, a demux 1240-2, constellation mapers 1250-1 and 1250 -2). ≪ / RTI > The BICM encoder 1200 may further include a time interleaver (not shown). The L1 signaling generator 1210 may also be included in the input processor 1100.

n service data are mapped to PLP0 to PLPn, respectively. The scheduler 1110 determines the position, modulation, and code rates for each PLP in order to map a plurality of PLPs to the physical layer of T2. That is, the scheduler 1110 generates the L1 signaling. In some cases, the scheduler 1110 may output dynamic information to the frame builder 1300 during the L1 post signaling of the current frame. In addition, the scheduler 1110 may send the L1 signaling to the BICM encoder 1200. The L1 signaling includes L1 pre-signaling and L1 post signaling.

The L1 signaling generator 1210 distinguishes between L1 pre-signaling and L1 post-signaling. FEC encoders 1220-1 and 1220-2 perform FEC encoding including shortening and puncturing for L1 pre-signaling and L1 post-signaling, respectively. The bit interleaver 1230-2 performs bit interleaving on the encoded L1 post signaling. The demux 1240-2 controls the order of the bits constituting the cell to control the robustness of the bits and outputs the cells including the bits. The two constellation mappers 1250-1 and 1250-2 map the cells of the L1 pre-signaling and the L1 post-signaling, respectively, to the constellation. The L1 pre-signaling and the L1 post signaling processed through the above-described process are output to the frame builder 1230. Thus, the L1 pre-signaling and the L1 post signaling can be inserted in the frame.

4 to 6 are views for explaining a unit structure of a transmission frame according to an embodiment of the present invention.

The input processing module in which the input stream is processed as an L1 packet, as shown in Fig. 4, may operate at the data pipe level.

4 illustrates a process in which an input stream is processed as an L1 packet, and a plurality of input streams 411 to 413 are processed by data pipes 421 to 423 for a plurality of L2 packets through an input pre-processing process , Data pipes 421 to 423 for a plurality of L2 packets are encapsulated into data pipes 431 to 433 for a plurality of L1 packets through an input processing process, and are scheduled in a transmission frame (FIG. 3, 1110). Here, the L2 packet may be of two types: a fixed stream such as a TS (Transport Stream) stream and a variable stream such as a GSE (General Stream Encapsulation) stream. Here, the L2 packet may correspond to a baseband packet.

Specifically, the baseband packet is generated by the input processor unit 110, and may include a baseband header generator (not shown) and a baseband frame generator (not shown). The baseband frame generator (not shown) may transmit the generated baseband frame to a baseband frame scrambler (not shown).

A process of generating a baseband packet and a baseband frame in the input processor unit 110 is as follows. A baseband packet generator (not shown) may encode a packet (IP packet, TS packet, etc.) input from an input layer 2 or higher layer to generate a baseband packet.

A baseband header generator (not shown) may generate a header to be inserted into the baseband frame. Here, the header inserted in the baseband frame is referred to as a baseband header, and the baseband header includes information on the baseband frame.

The baseband frame generator (not shown) encapsulates the baseband header generated from the baseband header generator (not shown) into a baseband packet output from the baseband packet generator (not shown) Thereby generating a baseband frame.

The baseband frame scrambler (not shown) may mix the data stored in the baseband frame in a random order before the forward error correction code is added to each baseband frame to generate a scrambled baseband frame. The scrambled baseband frame is transmitted through the PLP and signal processing is performed.

5 is a diagram for explaining a local frame structure for each PLP.

As shown in FIG. 5, the L1 packet 430 includes a header, a data field, and a padding field.

The L1 packet 430 is processed by the L1 FEC packet 440 by adding the parity 432 through the FEC encoding process.

The L1 FEC packet 440 is processed by a FEC block 450 through a bit interleaving and a constellation mapping process, a plurality of FEC blocks are processed through a cell interleaving process into a time interleaving block 460, and a plurality of time interleaving blocks Thereby constructing an interleaving frame 470.

6 is a diagram for explaining a structure of an interleaving frame.

Referring to FIG. 6, an interleaving frame 470 may be transmitted through different transmission frames 461 and 462, and a plurality of transmission frames may form one super frame 480.

Meanwhile, one transmission frame 461 may be composed of a P1 symbol 10 indicating a start position of a frame, a P2 symbol 20 transmitting an L1 signal, and data symbols 30 transmitting data.

The P1 symbol 10 is located at the beginning of the transmission frame 461 and can be used to detect the starting point of the T2 frame. For example, the P1 symbol 10 may transmit 7 bits of information.

The P2 symbol 20 is located after the P1 symbol 10 of the T2 frame. In one transmission frame 461, a plurality of P2 symbols 20 may be included according to the FFT size. The number of P2 symbols 20 included according to the FFT size is as follows.

FFT size P2 symbol number 1K 16 2K 8 4K 4 8K 2 16K One 32K One

The P2 symbol 20 includes L1 pre-signaling 21 and L1 post signaling 23. [ The L1 pre-signaling 21 provides basic transmission parameters including the parameters required to receive and decode the L1 post signaling.

The L1 post signaling 23 includes configurable post signaling 23-1 and dynamic post signaling 23-2. In addition, the L1 post signaling 23 may optionally include an extension field 23-3. Also, although not shown in the figure, the L1 post signaling 23 may further include a CRC field and, if necessary, an L1 padding field.

7 is a block diagram showing a detailed configuration of a transmitting unit according to an embodiment of the present invention.

7, the transmitter 140 includes a Tone Reservation and Pilot Generation unit 141, a Cell Multiplexer unit 142, an IFFT unit 143, a PAPR reduction unit 144, a GI Insertion unit 145, a Spectrum Shaping Unit 146 and a D / A conversion unit 147.

The Tone Reservation and Pilot Generation unit 141 and the Cell Multiplexer unit 142 multiplex the continuous pilot and the scattered pilot together with the data cell in the ATSC 3.0 frame. Accordingly, the receiving apparatus can perform channel estimation using the pilot, and can correct the frequency offset. Also, the Tone Reservation can be selectively used for PAPR reduction.

The IFFT unit 143 converts the ATSC 3.0 frame in which the pilot and reservation tone are inserted into a signal on the time axis.

The PAPR reduction unit 144 calculates the size of the PAPR pilot in the converted signal on the time axis, thereby reducing the size of the PAPR. Specifically, PAPR refers to a ratio of peak power to average power as a criterion for indicating the influence of the baseband transmission signal on the transmitter. In other words, in general, the power of the transmitter means the average power, but the peak power is present in the actually transmitted power, and when this peak power is not properly designed, it intermodulates and causes a deterioration of broadcast quality. Accordingly, the broadcast signal transmitting apparatus 100 must transmit a broadcast signal so that the PAPR becomes small.

Thereafter, the GI Insertion unit 145 inserts a guard interval into each symbol of the signal output from the PAPR reduction unit 144 to prevent interference between symbols.

The transmission unit 140 includes a spectrum shaping unit 146 for filtering a signal corresponding to the OFDM symbol.

The spectrum forming unit 146 may perform filtering on the signal output from the GI Insertion unit 145 to minimize interference between adjacent transmission channels.

Specifically, filtering is proposed to improve spectral formation and clarify the distinction between adjacent channels after OFDM symbols are generated. In general, the impulse response of filtering for spectral shaping reduces the length of the effective signal, It is required to shorten the length. However, flat filters without ripples are inevitably a filter having a high degree. Accordingly, it is required to shorten the length of the filter while performing effective spectrum formation of the OFDM signal in order to minimize the length of the filter and the loss of the effective guard interval.

8 is a diagram for explaining a process of spectrum formation and signal distortion according to an embodiment of the present invention.

8, the payload data and pilot are input to the framing unit 810, and when the frame is generated, the generated frame can be subjected to signal distortion by the linear pre-distortion unit 820 have.

Ripple is generated when a filter with a small impulse response and a steep slope signal attenuation, rather than a gentle slope, is selected. To obtain flat characteristics in one bandwidth, a linear pre-distortion is processed . In this way, the linear pre-distortion unit 820 plays a role of supplementing the selected filter.

The signal subjected to the signal distortion processing is subjected to IFFT processing in the IFFT unit 830 to be converted into a signal on the time axis, and is filtered by the filter 840.

That is, the spectrum forming unit 146 may generate a predetermined type of signal by increasing the amount of attenuation of the signal while decreasing the length of the filtering interval of the signal corresponding to the OFDM symbol. When the length of the filtering interval of the signal corresponding to the OFDM symbol is shortened, a ripple or a signal that is out of a predetermined format is generated. The linear pre-distortion unit 820 suppresses the ripple or the signal, (840) can increase the amount of attenuation of the signal magnitude so that the filtered signal has a steep slope rather than a gentle slope.

9 is a diagram illustrating a spectrally formed signal in accordance with an embodiment of the present invention.

Referring to FIG. 9, it can be seen that the signal 910 corresponding to an OFDM symbol not spectrally formed, and the waveform of the spectrally formed signal 920 are processed by filtering and signal distortion.

Specifically, it can be seen that a signal 910 corresponding to an OFDM symbol not having a spectrum formed has a ripple phenomenon in which the magnitude increases to about 10 dB at a frequency of 6 MHz, and attenuation occurs at about 35 dB.

However, it can be seen that the filtering and signal distortion are processed so that the spectrally formed signal 920 attenuates about 50 dB while maintaining a flat state without ripple phenomenon up to the boundary of 6 MHz.

That is, filtering and signal distortion are processed so that the spectrally formed signal 920 does not have a ripple phenomenon and attenuation occurs more rapidly than the signal 910 corresponding to an OFDM symbol not spectrally formed, .

Then, a tradeoff is required between the increase of the impulse response period and the amount of the attenuation, and this tradeoff can be changed according to the order of the filter function. In addition, the degree of the filter function can be determined according to the selected OFDM parameter, i.e., the FFT size or the guard interval size.

Referring again to FIG. 7, the D / A converter 147 converts the spectrum-formed signal into an analog signal and transmits the analog signal.

Meanwhile, the ATSC 3.0 physical layer system according to an embodiment of the present invention can be applied to a new system.

Specifically, an 8-VSB (Vsdtial Side Band) is currently transmitted for DTT (Digital Terrestrial Television) service. These services are targeted at fixed and mobile devices. At present, broadcasters must first purchase new transmission equipment to provide ATSC 3.0 services.

Thereafter, at least two broadcasters will need an alternative to provide a new ATSC 3.0 service. For example, in order to provide new ATSC 3.0 services while maintaining equipment to support SDTV programs, broadcasters need to choose whether to change fixed and mobile devices or only mobile devices to target devices.

If a broadcaster decides to transmit to both fixed and mobile devices, it will need more capper than other broadcasters use. For example, if broadcaster A decides to support both 4K television and HDTV mobile devices, the capper for the other broadcaster B must be small.

However, if broadcasters A and B decide to provide HDTV services for both fixed and mobile devices, then both broadcasters will have a capper to provide ATSC 3.0 services.

On the other hand, it is possible to change from an RF channel to an ATSC 3.0 service based on time division of broadcasters. This can be determined based on the number of receiving apparatuses existing in the same broadcast area. The key to this service delivery approach is that there is sufficient allocated channel space to service fixed and mobile devices without having to consider splitting the spectrum capper with other broadcasters.

Also, as the 8-VSB service and the ATSC 3.0 service are provided, the TV can operate in at least one of an 8-VSB mode and an ATSC mode.

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

10, a receiving apparatus 1000 includes a receiving unit 1010, a storage unit 1020, and a signal processing unit 1030. [

The receiving unit 1010 receives a stream including a pilot inserted in an OFDM symbol based on at least one of a plurality of pilot patterns set based on an OFDM symbol, an FFT size, and a guard interval interval (Guard Interval Fraction).

The storage unit 1030 stores information on a plurality of pilot patterns.

The signal processing unit 1020 determines a pilot pattern used for the OFDM symbol among a plurality of pilot patterns based on the signaling information of the stream, detects the pilot according to the determined pilot pattern, performs channel estimation using the detected pilot , And data can be detected by signal processing the OFDM symbol.

Here, the signal corresponding to the OFDM symbol is filtered so as to be converted into a predetermined type of signal, and the guard interval period is defined as shown in Table 1 according to the mode in which the FFT sizes are 8K, 16K, and 32K, Is defined as shown in Table 3 on the basis of the FFT size and the guard interval Fraction in a single input single output (SISO) mode. In the Multiple Input Single Output (MISO) mode, an FFT size and a guard interval Interval Fraction). ≪ tb > < TABLE >

The signal processing unit 1020 determines information on the pilot pattern selected based on the FFT size and the guard interval period based on the signaling information of the stream, and based on the information on the plurality of pilot patterns stored in the storage unit 1030, Obtain information about the pattern.

The signal processor 1020 detects the pilot inserted in the received stream based on the information on the selected pilot pattern, and can thereby perform channel estimation using the pilot.

11 is a block diagram illustrating a configuration of a receiving apparatus according to another embodiment of the present invention.

11, a receiving apparatus 1000 includes a receiving unit 1010, a storage unit 1020, a signal processing unit 1030, and a signaling processing unit 1040. [

Here, the receiving unit 1010, the storage unit 1020, and the signal processing unit 1030 have been described in advance, and a detailed description thereof will be omitted.

The signaling processing unit 1040 can extract the signaling information from the received stream. In particular, the signaling processor 1040 may extract and decode the L1 signaling to obtain information about the pattern of the inserted pilot. In addition, the signaling processor 1040 can obtain values relating to information about a protocol version of a frame, information on a type of a frame, and information on an insertion method of data.

12 is a block diagram specifically illustrating a signal processing unit according to an embodiment of the present invention.

12, the signal processing unit 1030 includes a demodulator 1031, a signal decoder 1032, and a stream generator 1033.

The demodulator 1031 demodulates the received RF signal according to the OFDM parameter to perform sync detection. When the sync is detected, the demodulator 1031 recognizes whether a mobile frame is received or a fixed frame is received from the information stored in the sink area do.

In this case, if the OFDM parameters for the signaling area and the data area are not predetermined, the OFDM parameters for the signaling area and the data area stored in the sink area are obtained and the signaling area and the data area OFDM parameter information and perform demodulation.

The signal decoder 1032 performs decoding on the input data. In this case, the signal decoder 1032 can obtain parameters such as the FEC scheme and the modulation scheme for data stored in each data area using the signaling information, and perform decoding. Further, the signal decoder 1032 can calculate the start position of data based on the data information included in the configurable post signaling and the dynamic post signaling. That is, it is possible to calculate at which position of the frame the corresponding PLP is transmitted.

The stream generator 1033 can process the BB frame (BB FRAME) received from the signal decoder 1032 to generate data to be served.

The stream generator 1033 generates an L2 packet from the error-corrected L1 packet based on information about the protocol version of the frame provided by the signaling processing unit 1040, information on the type of the frame, Can be generated.

Specifically, the stream generator 1033 may include de-jitter buffers, which may include information about the protocol version of the frame provided by the signaling processor 1032, information about the type of frame, The correct timing for restoring the output stream can be regenerated on the basis of the value relating to the information on the output stream. Thus, a delay for synchronization between a plurality of PLPs can be compensated.

13 is a block diagram illustrating the configuration of a signaling processing unit according to an embodiment of the present invention.

13, the signaling processing unit 1040 includes a demodulator 1041, a multiplexer 1042, a deinterleaver 1043, and a decoder 1044. [

The demodulator 1041 receives and demodulates the signal transmitted from the transmitting apparatus 100. [ Specifically, the demodulator 1041 demodulates the received signal to generate a value corresponding to the LDPC codeword, and outputs it to the multiplexer 1042.

In this case, the value corresponding to the LDPC codeword can be represented by the channel value for the received signal. Here, the channel value may be determined in various ways, for example, a method of determining a log likelihood ratio (LLR) value.

Here, the LLR value can be represented by a value obtained by taking a log as a ratio of the probability that the bits transmitted from the transmitting apparatus 100 are 0 and the probability of one day. Alternatively, the LLR value may be a bit value determined according to a hard decision, and the LLR value may be a representative value determined according to a period in which the probability that the bit transmitted from the transmitting apparatus 100 is 0 or 1 .

The multiplexer 1042 multiplexes the output value of the demodulator 221 and outputs it to the deinterleaver 1043. Here, the output value of the demodulator 1041 corresponds to the LDPC codeword, and may be an LLR value, for example.

Specifically, the MUX 1042 is a component corresponding to the DEMUX (FIG. 3, 1240-2) included in the transmitting apparatus 100, and performs a demultiplexing operation performed in the DEMUX 1240-2 inversely can do. That is, the multiplexer 222 performs a parallel-to-serial conversion on the value corresponding to the LDPC codeword output from the demodulator 221 to multiplex the value corresponding to the LDPC codeword.

The deinterleaver 1043 deinterleaves the output value of the MUX 1042 and outputs it to the decoder 1044. [

Specifically, the deinterleaver 1043 is a component corresponding to the interleaver (FIG. 3, 1230-2) provided in the transmitting apparatus 100, and performs inverse operations performed in the interleaver (FIG. 3, 1230-2) can do. That is, the deinterleaver 1043 can deinterleave the values corresponding to the LDPC codeword so as to correspond to the interleaving operation performed in the interleaver (FIG. 3, 1230-2). Here, the value corresponding to the LDPC codeword can be an LLR value as an example.

The decoder 1044 is a component corresponding to the FEC encoder 1220-2 provided in the transmission apparatus 100 and can perform an operation performed by the FEC encoder 1220-2 inversely. Specifically, the decoder 1044 may perform decoding based on the deinterleaved LLR value to output L1 signaling.

14 is a flowchart illustrating a method of controlling a transmitting apparatus according to an embodiment of the present invention.

According to the method shown in Fig. 14, a plurality of input streams are divided into a plurality of baseband frames (S1410).

Then, forward error coding is performed on each of the plurality of baseband frames, and constellation mapping and interleaving are performed (S1420).

Thereafter, signaling data is added to a plurality of interleaved baseband frames to generate an OFDM symbol (S1430).

Also, at least one of the plurality of pilot patterns is selected based on the FFT size and guard interval fractions, a pilot is inserted into the OFDM symbol according to the selected pilot pattern, And transmits the stream (S1440).

Here, the transmitting step includes spectrum shaping for filtering a signal corresponding to an OFDM symbol.

In the spectrum forming step, a predetermined type of signal can be generated by increasing the amount of attenuation of the signal while reducing the length of the filtering interval of the signal corresponding to the OFDM symbol.

Meanwhile, the guard interval interval is defined as shown in Table 1 according to the modes in which the FFT sizes are 8K, 16, and 32K.

The plurality of pilot patterns are defined as shown in Table 3 based on the FFT size and the guard interval period in the SISO (Single Input Single Output) mode.

Also, a plurality of pilot patterns are defined as shown in Table 4 based on the FFT size and the guard interval period in the MISO (Multiple Input Single Output) mode.

15 is a flowchart illustrating a method of controlling a receiving apparatus according to an embodiment of the present invention.

According to the method shown in FIG. 15, a stream including a pilot inserted in an OFDM symbol is received based on at least one of a plurality of pilot patterns set based on an OFDM symbol and an FFT size and a guard interval interval (Guard Interval Fraction) (S1510).

Then, a pilot pattern used for the OFDM symbol is determined from a plurality of pre-stored pilot patterns based on the signaling information of the stream, and a pilot is detected according to the determined pilot pattern (S1520).

Thereafter, channel estimation is performed using the detected pilot, and signal processing of the OFDM symbol is performed to detect data (S1530).

Here, the signal corresponding to the OFDM symbol is filtered so as to be converted into a predetermined type of signal.

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

For example, the method includes dividing a plurality of input streams into a plurality of baseband frames, forward error-coded each of the plurality of baseband frames, and performing constellation mapping and interleaving, performing signaling on a plurality of interleaved baseband frames Adding the data to generate an OFDM symbol, selecting at least one of a plurality of pilot patterns based on the FFT size and the guard interval period, inserting a pilot in the OFDM symbol according to the selected pilot pattern, A non-transitory computer readable medium may be provided.

Also, in one example, the method includes receiving a stream including a pilot inserted in an OFDM symbol based on at least one of a plurality of pilot patterns set based on an OFDM symbol and an FFT size and a guard interval period, Determining a pilot pattern used for the OFDM symbol among a plurality of previously stored pilot patterns, detecting a pilot according to the determined pilot pattern, performing channel estimation using the detected pilot, signal processing the OFDM symbol, A non-transitory computer readable medium may be provided.

A non-transitory readable medium is a medium that stores data for a short period of time, such as a register, cache, memory, etc., but semi-permanently stores data and is readable by the apparatus. In particular, the various applications or programs described above may be stored on non-volatile readable media such as CD, DVD, hard disk, Blu-ray disk, USB, memory card, ROM,

Although the buses are not shown in the above-described block diagrams for the transmitting apparatus and the receiving apparatus, the communication between the respective elements in the transmitting apparatus and the receiving apparatus may be performed via the bus. Further, each device may further include a processor such as a CPU, a microprocessor, or the like that performs the various steps described above.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention.

100: transmitting apparatus 110: input processor unit
120: BICM unit 130: Structure unit
140:

Claims (19)

An input processor unit for dividing a plurality of input streams into a plurality of baseband frames;
A bit interleaved and coded modulation (BICM) unit for performing forward error coding (CQI) on each of the plurality of baseband frames, performing constellation mapping and interleaving, and outputting the result;
A structure unit for generating OFDM symbols by adding signaling data to a plurality of baseband frames output from the BICM unit; And
Selecting at least one of a plurality of pilot patterns based on an FFT size and a guard interval interval, inserting a pilot into the OFDM symbol according to the selected pilot pattern, And a transmitting unit for transmitting a stream including the data. The method according to claim 1,
The transmitter may further comprise:
And a spectrum shaping unit for filtering a signal corresponding to the OFDM symbol. 3. The method of claim 2,
The spectrum-
And generates a predetermined type of signal by decreasing a length of a filtering interval of a signal corresponding to the OFDM symbol and increasing an amount of attenuation of the signal size. The method according to claim 1,
Wherein the guard interval interval is defined as follows according to a mode in which the FFT sizes are 8K, 16K, and 32K.

The method according to claim 1,
Wherein the plurality of pilot patterns are defined as shown in the following table based on the FFT size and guard interval fractions in a single input single output (SISO) mode.

The method according to claim 1,
Wherein the plurality of pilot patterns are defined as shown in the following table based on the FFT size and guard interval fractions in a multiple input single output (MISO) mode.

A receiver for receiving a stream including a pilot inserted in the OFDM symbol based on at least one of a plurality of pilot patterns set based on an OFDM symbol, an FFT size, and a guard interval interval (Guard Interval Fraction);
A storage unit for storing information on the plurality of pilot patterns; And
Determining a pilot pattern used for the OFDM symbol among the plurality of pilot patterns based on signaling information of the stream, detecting the pilot according to the determined pilot pattern, performing channel estimation using the detected pilot, And a signal processing unit for signal processing OFDM symbols to detect data. 8. The method of claim 7,
The signal corresponding to the OFDM symbol may be,
Wherein the filtering is performed so as to be converted into a predetermined type of signal. 8. The method of claim 7,
Wherein the guard interval interval is defined as follows according to a mode in which the FFT size is 8K, 16K, 32K.

8. The method of claim 7,
Wherein the plurality of pilot patterns are defined as shown in the following table based on the FFT size and the guard interval interval in a single input single output (SISO) mode.

8. The method of claim 7,
Wherein the plurality of pilot patterns are defined as shown in the following table based on the FFT size and guard interval fractions in a multiple input single output (MISO) mode.

Dividing a plurality of input streams into a plurality of baseband frames;
Performing forward error coding (CSI) on each of the plurality of baseband frames and performing constellation mapping and interleaving;
Generating OFDM symbols by adding signaling data to a plurality of interleaved baseband frames; And
Selecting at least one of a plurality of pilot patterns based on an FFT size and a guard interval interval, inserting a pilot into the OFDM symbol according to the selected pilot pattern, And transmitting the stream including the stream. 13. The method of claim 12,
Wherein the transmitting comprises:
And a spectrum shaping step of filtering a signal corresponding to the OFDM symbol. 14. The method of claim 13,
Wherein the spectral shaping step comprises:
Wherein a signal of a predetermined type is generated by increasing an amount of attenuation of the signal while reducing a length of a filtering interval of a signal corresponding to the OFDM symbol. 13. The method of claim 12,
Wherein the guard interval interval is defined according to a mode in which the FFT size is 8K, 16K, and 32K as shown in the following table.

13. The method of claim 12,
Wherein the plurality of pilot patterns are defined as shown in the following table based on the FFT size and guard interval fractions in a single input single output (SISO) mode.

13. The method of claim 12,
Wherein the plurality of pilot patterns are defined as shown in the following table based on the FFT size and guard interval fractions in a multiple input single output (MISO) mode.

Comprising: receiving a stream including a pilot inserted in the OFDM symbol based on at least one of a plurality of pilot patterns set based on an OFDM symbol, an FFT size, and a guard interval interval (Guard Interval Fraction);
Determining a pilot pattern used for the OFDM symbol from a plurality of pre-stored pilot patterns based on signaling information of the stream, and detecting the pilot according to the determined pilot pattern; And
Performing channel estimation using the detected pilot and signal processing the OFDM symbol to detect data. 19. The method of claim 18,
The signal corresponding to the OFDM symbol may be,
Wherein the filtering is performed so as to be converted into a predetermined type of signal.

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