Broadcast signal transmission apparatus and method using multiple transmission antennas and layer division multiplexing

Abstract

Disclosed are a broadcast signal transmission apparatus and method using multiple transmission antennas and layer division multiplexing. The broadcast signal transmission apparatus according to an embodiment of the present invention comprises: a core layer signal generation unit that generates a core layer signal; an enhanced-layer multiple input multiple output (MIMO) signal generation unit that generates enhanced-layer MIMO signals; an LDM combining unit that hierarchically division-multiplexes the core layer signal and one of the enhanced-layer MIMO signals to output a first polarization signal corresponding to a first polarization, and outputs another of the enhanced-layer MIMO signals as a second polarization signal corresponding to a second polarization; and a transmission signal generation unit that generates a first polarization transmission signal by using the first polarization signal, and generates a second polarization transmission signal by using the second polarization signal.

Description

Broadcast signal transmission device using multiple transmission antennas and hierarchical division multiplexing and method using the same

[0001] The present invention relates to a broadcast signal transmission / reception system that simultaneously supports layered division multiplexing technology and MIMO (Multi-Input Multi-Output) technology, and more particularly, to a technology for transmitting / receiving a pilot.

[0002] To address the growing demand for ultra-high-definition broadcasting services, efficient use of frequency resources, and the integration of services requiring diverse regions and reception environments, technologies and standards for next-generation terrestrial broadcasting systems have recently been introduced. However, the growing demand for higher resolutions, hyper-realistic media such as AR (Artificial Reality) and VR (Virtual Reality), and additional data for enhanced user experiences, coupled with the lack of idle frequency resources due to the simultaneous provision of existing broadcasting services, necessitates further improvements in the transmission rates of terrestrial broadcasting systems.

[0003] The latest terrestrial digital broadcasting standards, such as ATSC 3.0, have attempted to overcome the transmission capacity limitations of a single broadcast frequency by applying multiple antenna technologies such as MIMO (Multiple Input Multiple Output), and have adopted layered division multiplexing technology in addition to TDM (Time Division Multiplexing) or FDM (Frequency Division Multiplexing) to support multiple services simultaneously.

[0004] MIMO used in ATSC 3.0 is a technology that increases transmission capacity by transmitting two data streams on a single RF (Radio Frequency) channel using orthogonal polarization antennas. At this time, the orthogonal polarization antennas are composed of two antennas whose polarizations are orthogonal to each other, and it takes into account the environment in which both vertical polarization antennas and horizontal polarization antennas are installed at the transmitter and receiver. This type of MIMO is called 2X2 cross-polarized MIMO. At this time, each polarization antenna can be referred to as antenna #1 (ANT 1) and antenna #2 (ANT 2), and in this case, antenna #1 can be a vertical polarization antenna and antenna #2 a horizontal polarization antenna, or conversely, antenna #1 can be a horizontal polarization antenna and antenna #2 a vertical polarization antenna.

[0005] Hierarchical division multiplexing is somewhat more complex than TDM and FDM, but it offers a high level of flexibility and improved system performance.

[0006] Layered division multiplexing (LDM) refers to a system that combines multiple layers into a single transmission layer. In its simplest form, a system with two layers—a core layer and an enhanced layer—is considered. The core layer typically refers to a layer with higher reception robustness than the enhanced layer. In the ATSC 3.0 standard, the transmit power allocated to the core layer is significantly greater than that allocated to the enhanced layer, inducing the receiver to prioritize decoding of the core layer.

[0007] Korean Patent Publication No. 10-2018-0132525 proposes a structure that combines MIMO and layered division multiplexing (LDM) technology for broadcast signal transmission and reception. Specifically, Korean Patent Publication No. 10-2018-0132525 discloses two structures: one in which MIMO is applied to both the core and enhanced layers, and one in which MIMO is applied to only one of the core or enhanced layers.

[0008] When MIMO is applied to a broadcast signal transmission / reception system, the receiver must be equipped with two antennas (a vertically polarized antenna and a horizontally polarized antenna) to fully restore the transmitted MIMO signal, and a conventional single-antenna receiver cannot receive a signal transmitted using the MIMO method. In other words, since MIMO separates a single service into two different streams and then transmits the separated streams to each antenna, a single-antenna receiver cannot restore the original service.

[0009] Therefore, when configuring LDM multiplexing including MIMO transmission signals, compatibility with existing single-antenna receivers must be considered.

[0010] If there is no need to ensure compatibility with existing single-antenna receivers, MIMO can be applied to both the core layer and the enhanced layer when applying LDM and MIMO technologies together.

[0011] However, when LDM and MIMO technologies are used together while ensuring compatibility with existing single-antenna receivers, the core layer can use SISO (Single Input Single Output) and the enhanced layer can use MIMO. In this case, SISO may not separate a single service into multiple streams and transmit them independently. Even when two antennas transmit the same signal, it can still be considered SISO.

[0012] Korean Patent Publication No. 10-2023-0130564 discloses an LDM and MIMO combined structure in which SISO is applied to the core layer and MIMO is applied to the enhanced layer. In the structure disclosed in Korean Patent Publication No. 10-2023-0130564, a SISO transmission signal is generated for the core layer, and a MIMO transmission signal is generated for the enhanced layer. At this time, the SISO receiver does not consider the MIMO signal (considering it as noise) and restores the core layer signal, and the MIMO receiver first restores the SISO signal (core layer signal) and then removes it from the received signal, and then restores the received signal from which the SISO signal has been removed using the MIMO method.

[0013] However, No. 10-2023-0130564 only presents LDM and a rough combination structure of them when SISO and MIMO are used together, and is completely silent on how pilots should be used in broadcast signal transmitters / receivers to ensure compatibility with existing single-antenna receivers.

[0014] Therefore, there is an urgent need for a new pilot transmission / reception technology that can utilize both layered division multiplexing and MIMO technologies while ensuring compatibility with existing SISO receivers.

[0015] The purpose of the present invention is to propose a new method of using a scattered pilot pattern to enable the use of layered division multiplexing and MIMO technologies together while ensuring compatibility with existing SISO receivers.

[0016] In addition, it is an object of the present invention to enable a MIMO receiver that receives a transmission signal to which LDM and MIMO are applied together to properly receive a pilot signal, while also allowing a legacy SISO receiver to properly receive a pilot signal for core layer signal restoration.

[0017] In addition, it is an object of the present invention to prevent collision between pilot-related signaling information for a legacy SISO receiver and pilot-related signaling information for a MIMO receiver when a transmission signal to which LDM and MIMO are applied together is transmitted.

[0018] In order to achieve the above object, a broadcast signal transmission device according to the present invention includes a core layer signal generation unit that generates a core layer signal; an enhanced layer MIMO signal generation unit that generates enhanced layer MIMO (Multiple Input Multiple Output) signals; an LDM combiner that hierarchically multiplexes one of the core layer signal and the enhanced layer MIMO signals to output a first polarization signal corresponding to a first polarization and outputs the other one of the enhanced layer MIMO signals as a second polarization signal corresponding to a second polarization; and a transmission signal generation unit that generates a first polarization transmission signal using the first polarization signal and a second polarization transmission signal using the second polarization signal.

[0019] At this time, in the first polarization, at least one SISO (Single Input Single Output) PLP (Physical Layer Pipe) and at least one MIMO PLP superposed with the at least one SISO PLP can share pilot cells.

[0020] At this time, the first polarization transmission signal and the second polarization transmission signal can be generated using only the first MIMO distributed pilot encoding among the first MIMO distributed pilot encoding that transmits pilots to the same OFDM cell positions for the first polarization and the second polarization, and the second MIMO distributed pilot encoding that transmits pilots to different OFDM cell positions for the first polarization and the second polarization.

[0021] At this time, the first MIMO distributed pilot encoding may correspond to a first group in which identical pilots are transmitted for the first polarization and the second polarization, and a second group in which pilots with opposite phases are transmitted for the first polarization and the second polarization.

[0022] At this time, the second MIMO distributed pilot encoding may correspond to a first group in which only pilots for the first polarization are transmitted with valid power and pilots for the second polarization are transmitted with null power, and a second group in which only pilots for the second polarization are transmitted with valid power and pilots for the first polarization are transmitted with null power.

[0023] At this time, the first MIMO distributed pilot encoding may be Walsh-Hadamard encoding, and the second MIMO distributed pilot encoding may be null pilot encoding.

[0024] At this time, at least one of the first polarization transmission signal and the second polarization transmission signal may include a preamble, and the preamble may include a 1-bit L1B_mimo_scattered_pilot_encoding field set to 0.

[0025] At this time, the 1-bit L1B_mimo_scattered_pilot_encoding field set to 0 can indicate both a MIMO pilot pattern with Walsh-Hadamard encoding and the SISO pilot pattern simultaneously.

[0026] In addition, a broadcast signal transmission method according to an embodiment of the present invention includes the steps of: generating a core layer signal; generating enhanced layer MIMO (Multiple Input Multiple Output) signals; hierarchically multiplexing one of the core layer signal and the enhanced layer MIMO signals to output a first polarization signal corresponding to a first polarization, and outputting the other one of the enhanced layer MIMO signals as a second polarization signal corresponding to a second polarization; and generating a first polarization transmission signal using the first polarization signal and a second polarization transmission signal using the second polarization signal.

[0027] At this time, in the first polarization, at least one SISO (Single Input Single Output) PLP (Physical Layer Pipe) and at least one MIMO PLP superposed with the at least one SISO PLP can share pilot cells.

[0028] At this time, the first polarization transmission signal and the second polarization transmission signal can be generated using only the first MIMO distributed pilot encoding among the first MIMO distributed pilot encoding that transmits pilots to the same OFDM cell positions for the first polarization and the second polarization, and the second MIMO distributed pilot encoding that transmits pilots to different OFDM cell positions for the first polarization and the second polarization.

[0029] At this time, the first MIMO distributed pilot encoding may correspond to a first group in which identical pilots are transmitted for the first polarization and the second polarization, and a second group in which pilots with opposite phases are transmitted for the first polarization and the second polarization.

[0030] At this time, the second MIMO distributed pilot encoding may correspond to a first group in which only pilots for the first polarization are transmitted with valid power and pilots for the second polarization are transmitted with null power, and a second group in which only pilots for the second polarization are transmitted with valid power and pilots for the first polarization are transmitted with null power.

[0031] At this time, the first MIMO distributed pilot encoding may be Walsh-Hadamard encoding, and the second MIMO distributed pilot encoding may be null pilot encoding.

[0032] At this time, at least one of the first polarization transmission signal and the second polarization transmission signal may include a preamble, and the preamble may include a 1-bit L1B_mimo_scattered_pilot_encoding field set to 0.

[0033] At this time, the 1-bit L1B_mimo_scattered_pilot_encoding field set to 0 can indicate both a MIMO pilot pattern with Walsh-Hadamard encoding and the SISO pilot pattern simultaneously.

[0034] In addition, in one embodiment of the present invention, a broadcast signal receiving method includes the steps of: receiving a broadcast signal including a preamble; restoring a 1-bit L1B_mimo_scattered_pilot_encoding field and a scattered pilot pattern identification field included in the preamble; identifying a scattered pilot pattern using the scattered pilot pattern identification field; and performing channel estimation based on the identified scattered pilot pattern.

[0035] At this time, the distributed pilot pattern identification field can be shared with a SISO (Single Input Single Output) receiver and a MIMO (Multiple Input Multiple Output) receiver.

[0036] At this time, the L1B_mimo_scattered_pilot_encoding field may be set to 0 to indicate both a MIMO pilot pattern with Walsh-Hadamard encoding and the SISO pilot pattern simultaneously.

[0037] At this time, the MIMO receiver can receive pilot cells shared by at least one SISO PLP (Physical Layer Pipe) and at least one MIMO PLP superposed with the at least one SISO PLP in the first polarization.

[0038] According to the present invention, a new method of using a scattered pilot pattern is provided to enable the use of layered division multiplexing and MIMO technologies together while ensuring compatibility with existing SISO receivers.

[0039] In addition, the present invention can enable a MIMO receiver that receives a transmission signal to which LDM and MIMO are applied together to properly receive a pilot signal, while also enabling a legacy SISO receiver to properly receive a pilot signal for core layer signal restoration.

[0040] In addition, the present invention can prevent collision between pilot-related signaling information for a legacy SISO receiver and pilot-related signaling information for a MIMO receiver when a transmission signal to which LDM and MIMO are applied together is transmitted.

[0041] Figures 1 and 2 are diagrams showing two transmission examples in which SISO is applied to the core layer and MIMO is applied to the enhanced layer.

[0042] FIG. 3 is a block diagram showing an example of a broadcast signal transmission device according to one embodiment of the present invention.

[0043] Fig. 4 is a block diagram showing an example of the LDM coupling unit illustrated in Fig. 3.

[0044] Figure 5 is a diagram showing an example of a SISO distributed pilot pattern corresponding to SP3_2.

[0045] FIG. 6 is a diagram showing an example of a Walsh-Hadamard encoded MIMO distributed pilot pattern corresponding to MP3_2.

[0046] FIG. 7 is a diagram showing an example of a null pilot encoded MIMO distributed pilot pattern corresponding to MP3_2.

[0047] FIG. 8 is a diagram showing an example of a transmission signal configuration when a SISO signal is transmitted only through one of two MIMO antennas.

[0048] FIG. 9 is a diagram showing an example of a transmission signal configuration when a SISO signal is transmitted through both MIMO antennas.

[0049] Figure 10 is a diagram comparing a SISO distributed pilot pattern and a MIMO distributed pilot pattern.

[0050] Figure 11 is a flowchart illustrating a broadcast signal transmission method according to one embodiment of the present invention.

[0051] Figure 12 is a flowchart illustrating a broadcast signal receiving method according to one embodiment of the present invention.

[0052] Figure 13 is a block diagram showing a computer system configuration according to one embodiment of the present invention.

[0053] The present invention will be described in detail with reference to the attached drawings. Herein, repetitive descriptions, well-known functions that may unnecessarily obscure the gist of the present invention, and detailed descriptions of configurations are omitted. The embodiments of the present invention are provided to more fully explain the present invention to those of ordinary skill in the art. Accordingly, the shapes and sizes of elements in the drawings may be exaggerated for clarity.

[0054] Hereinafter, a preferred embodiment according to the present invention will be described in detail with reference to the attached drawings.

[0055] Figures 1 and 2 are diagrams showing two transmission examples in which SISO is applied to the core layer and MIMO is applied to the enhanced layer.

[0056] When configuring LDM multiplexing including MIMO transmission signals, the SISO method can be applied to the core layer and MIMO can be applied only to the enhanced layer, considering compatibility with existing single-antenna receivers.

[0057] Referring to FIG. 1, it can be seen that the SISO signal (LEGACY SERVICE) of the core layer is transmitted only through one (VERTICAL) of the two MIMO antennas (VERTICAL, HORIZONTAL), and the other MIMO antenna (HORIZONTAL) does not transmit the core layer signal.

[0058] Referring to FIG. 2, it can be seen that two MIMO antennas (VERTICAL, HORIZONTAL) transmit the SISO signal (LEGACY SERVICE) of the same core layer in the core layer, and transmit two MIMO signals (STREAM 1, STREAM 2) in the enhanced layer, respectively.

[0059] That is, in the example illustrated in FIG. 1, the SISO signal transmitted to the core layer is transmitted through only one antenna, and in the example illustrated in FIG. 2, the SISO signal transmitted to the core layer is transmitted through both antennas.

[0060] When LDM and MIMO technologies are used together in this combined form of SISO and MIMO, backward compatibility with existing SISO receivers must be guaranteed, so L1 signaling must be applicable to both SISO and MIMO receivers. Therefore, from the perspective of existing SISO receivers, L1 signaling fields must be transmitted in the same manner as in the existing SISO transmission method to ensure normal operation of the SISO receiver.

[0061] FIG. 3 is a block diagram showing an example of a broadcast signal transmission device according to one embodiment of the present invention.

[0062] Figure 3 shows an example of a transmitter configuration in which a SISO signal is transmitted through a core layer and a MIMO signal is transmitted through an enhanced layer.

[0063] Referring to FIG. 3, a broadcast signal transmission device according to one embodiment of the present invention includes a core layer signal generation unit (310), an enhanced layer MIMO signal generation unit (320), an LDM combining unit (330), and a transmission signal generation unit (340).

[0064] The core layer signal generation unit (310) generates a core layer signal (SISO signal).

[0065] The core layer signal generation unit (310) includes an input formatting unit (311) and a core layer BICM (Bit-Interleaved Coded Modulation) unit (312).

[0066] The input formatting unit (311) generates packetized data (baseband packets) in units of processing blocks of the transmission system. At this time, the transmission system can classify packets to which the same BICM (Bit Interleaved Coded Modulation) and transmission signal generation parameters are applied and define them as the same PLP (Physical Layer Pipe).

[0067] The core layer BICM unit (312) may include an FEC (Forward Error Correction) unit, a BIL (Bit Interleaver) unit, and a symbol mapping unit. At this time, the FEC unit may apply channel coding to baseband packets to generate FEC frames (FEC packets), which are groups of bits. At this time, the channel coding may be a single-structure method, or may be a method composed of multiple stages, such as inner and outer coding. At this time, the BIL unit may perform bit interleaving on the FEC frames output from the FEC unit. At this time, the symbol mapping unit may generate data cells for transmitting output to be transmitted through an antenna for the output bit string of the BIL unit, and output them as core layer signals.

[0068] The enhanced layer MIMO signal generation unit (320) generates enhanced layer MIMO (Multiple Input Multiple Output) signals.

[0069] The enhanced layer MIMO signal generation unit (320) includes an input formatting unit (321), an enhanced layer BICM unit (322), and a MIMO precoder (323).

[0070] The input formatting unit (321) generates packetized data (baseband packets) in units of processing blocks of the transmission system. At this time, the transmission system can classify packets to which the same BICM (Bit Interleaved Coded Modulation) and transmission signal generation parameters are applied and define them as the same PLP (Physical Layer Pipe).

[0071] The enhanced layer BICM unit (322) may include an FEC (Forward Error Correction) unit, a BIL (Bit Interleaver) unit, and a MIMO (Multi-Input Multi-Output) MAP (mapping) unit. At this time, the FEC unit may apply channel coding to baseband packets to generate FEC frames, which are groups of bits. At this time, the channel coding may be a single-structure method, or may be a method composed of multiple stages, such as inner and outer coding. At this time, the BIL unit may perform bit interleaving on the FEC frames output from the FEC unit. At this time, the MIMO MAP unit may generate data cells for transmitting the output to each of the multiple antennas for the output bit string of the BIL unit. For this purpose, the MIMO MAP unit may be composed of two detailed blocks: a demultiplexer unit and a bit to IQ mapping unit. At this time, the demultiplexer unit can group the input bit stream according to the modulation order and the number of multiple antennas in order to convert the input bit stream into data cells. At this time, the bit stream corresponding to each group may be different depending on the modulation order and the number of multiple antennas. The bit-to-IQ mapping unit maps the output of the demultiplexer unit to constellations corresponding to groups of bits corresponding to each antenna output, and generates data cells corresponding to each antenna output. In one embodiment, even-numbered bits in a bit group can be mapped to data cells for the first antenna (first polarization), and odd-numbered bits can be mapped to data cells for the second antenna (second polarization). At this time, the grouping of each bit in the MIMO MAP unit or the constellation mapping of the bits using the same can be performed using various methods not illustrated. At this time, the first polarization can be vertical polarization, and the second polarization can be horizontal polarization.

[0072] Here, polarization can be the orientation of the electric field vector of a radiated electromagnetic wave with respect to the horizon as seen from the antenna. In other words, polarization can describe the orientation of the wave emitted from. This orientation can be planar or circular.

[0073] Hereinafter, the first antenna may be replaced with the first polarization, and the second antenna may be replaced with the second polarization.

[0074] Two groups of data cells are input to the MIMO precoder (323).

[0075] At this time, the MIMO precoder (323) may include a streaming combiner, an IQ polarization interleaving unit, and a phase hopping unit. At this time, the stream combiner may combine two data cells inputted and output them. At this time, the IQ polarization interleaving unit may exchange the quadrature components of the two data cells inputted and output them. At this time, the phase hopping unit may change the phase of the data cells inputted and output them. At this time, all three sub-blocks may operate while being activated, all may operate while being deactivated, or only some of the blocks may operate while being activated. In addition, each sub-block may output a different signal or the same signal depending on the channel coding rate and modulation order applied to the data cells inputted to each sub-block. The MIMO precoder (323) illustrated in FIG. 3 can output two data cells to be output through the first antenna (first polarization) and the second antenna (second polarization).

[0076] The LDM combiner (330) hierarchically multiplexes one of the core layer signal and the enhanced layer MIMO signals to output a first polarization signal corresponding to the first polarization (first antenna), and outputs the other one of the enhanced layer MIMO signals as a second polarization signal corresponding to the second polarization (second antenna).

[0077] At this time, the LDM coupling unit (330) can output the second polarization signal with unity power.

[0078] The transmission signal generation unit (340) generates a first polarization transmission signal using the first polarization signal, and generates a second polarization transmission signal using the second polarization signal.

[0079] The transmission signal generation unit (340) includes framing & interleaving units (341, 342) and waveform generators (345, 346).

[0080] Time interleaving, frame generation (including preamble), and frequency interleaving can be performed in the framing & interleaving unit (341) on the first polarization signal output through the LDM combining unit (330). The output of the framing & interleaving unit (341) is input to the waveform generator (345) and output to the first antenna as the first polarization transmission signal.

[0081] Time interleaving, frame generation (including preamble), and frequency interleaving can be performed in the framing & interleaving unit (342) on the second polarization signal output through the LDM coupling unit (330). The output of the framing & interleaving unit (342) is input to the waveform generator (346) and output to the second antenna as the second polarization transmission signal.

[0082] The framing & interleaving units (341, 342) illustrated in FIG. 3 can each generate a signal corresponding to a frame to be transmitted via an antenna using data cells input as input. At this time, the framing & interleaving units (341, 342) may or may not activate and perform time interleaving for each input data cell. At this time, the framing & interleaving units (341, 342) may each perform framing for configuring preamble symbols and subframes for each data cell. At this time, the preamble symbol may not include a data cell. At this time, frequency interleaving may or may not be activated and applied.

[0083] Depending on the embodiment, the first polarization transmission signal and the second polarization transmission signal may each include a preamble, but only one of them may include a preamble.

[0084] If the first polarization transmission signal includes a first preamble and the second polarization transmission signal includes a second preamble, the first preamble and the second preamble may each include a 1-bit L1B_mimo_scattered_pilot_encoding field set to 0. Furthermore, the first preamble and the second preamble may include the same L1 signaling information.

[0085] If only one of the first polarization transmission signal and the second polarization transmission signal includes a preamble, this preamble can be applied not only to the polarization (antenna) transmitting the preamble but also to the other polarization (antenna). For example, if only the first polarization transmission signal includes a preamble, the signaling fields included in this preamble can be used by both the first polarization and the second polarization.

[0086] The grouped data cells, which are outputs of the framing & interleaving units (341, 342), are input to the waveform generators (345, 346). At this time, the waveform generators (345, 346) may each perform an inverse fast Fourier transform (IFFT) after pilot insertion and insert a guard interval symbol. In addition, the waveform generators (345, 346) may each generate a bootstrap symbol and output it by positioning it at the very beginning of the transmission frame.

[0087] In particular, the waveform generator (346) may apply power scaling for the second polarization in the IFFT stage according to an injection level corresponding to the second polarization (which may be the same as the injection level corresponding to the first polarization). At this time, the power of the second polarization transmission signal may be lower than the power of the first polarization transmission signal.

[0088] Information about the scattered pilots inserted through the waveform generators (345, 346) may be included in the preamble generated by the framing & interleaving units (341, 342).

[0089] FIG. 4 is a block diagram showing an example of the LDM coupling unit (330) illustrated in FIG. 3.

[0090] Referring to FIG. 4, the LDM coupling unit (330) includes an injection level controller (410), a coupler (420), and a power normalizer (430).

[0091] The LDM coupling unit (330) is a core layer signal (S C ) and enhanced layer MIMO signals (S E,1 , S E,2 ) one of (S E,1 ) is hierarchically divided into multiplexes to generate the first polarization signal (β(S) corresponding to the first polarization (POLARIZATION #1). C + αS E,1 )) and output enhanced layer MIMO signals (S E,1 , S E,2 ) another one (S) E,2 ) is output as a second polarization signal corresponding to the second polarization.

[0092] The injection level controller (410) provides enhanced layer MIMO signals (S) for hierarchical division multiplexing. E,1 , S E,2 ) one of (S E,1 ) to control the power.

[0093] The coupler (420) is a core layer signal (S C ) and one of the enhanced layer signals (αS) whose power is controlled by the injection level controller (410). E,1 ) are combined.

[0094] The power normalizer (430) performs transmission power normalization and outputs a first polarization signal.

[0095] In this way, the LDM combining unit illustrated in FIG. 4 combines the core layer signal and the enhanced layer signal through hierarchical division multiplexing for the first polarization, but for the second polarization, the combination of the two layer signals through hierarchical division multiplexing is not performed and the input MIMO signal (S E,2 ) is output as is. That is, in the structure illustrated in FIG. 4, constellation-superposed signals are transmitted only in the first polarization (POLARIZATION #1), and the second polarization (POLARIZATION #2) can transmit a dedicated MIMO stream composed solely of enhanced layer cells.

[0096] At this time, in the first polarization, at least one SISO (Single Input Single Output) PLP (Physical Layer Pipe) and at least one MIMO PLP superposed with the at least one SISO PLP can share pilot cells. That is, the SISO PLP(s) and MIMO PLP(s) superposed by the broadcast signal transmission apparatus illustrated in FIGS. 3 and 4 can share pilot cells transmitted through the first polarization (first antenna). This can be viewed as the pilot cells transmitted through the first polarization (first antenna) of the broadcast signal transmission apparatus illustrated in FIGS. 3 and 4 being shared by the core layer used for SISO transmission and the enhanced layer used for MIMO transmission.

[0097] At this time, the first polarization transmission signal and the second polarization transmission signal may be generated using only the first MIMO distributed pilot encoding among the first MIMO distributed pilot encoding that transmits pilots to the same OFDM cell positions for the first polarization and the second polarization, and the second MIMO distributed pilot encoding that transmits pilots to different OFDM cell positions for the first polarization and the second polarization.

[0098] At this time, the first MIMO distributed pilot encoding may correspond to a first group in which identical pilots are transmitted for the first polarization and the second polarization, and a second group in which pilots with opposite phases are transmitted for the first polarization and the second polarization.

[0099] At this time, the second MIMO distributed pilot encoding may correspond to a first group in which only pilots for the first polarization are transmitted with valid power and pilots for the second polarization are transmitted with null power, and a second group in which only pilots for the second polarization are transmitted with valid power and pilots for the first polarization are transmitted with null power.

[0100] At this time, the first MIMO distributed pilot encoding may be Walsh-Hadamard encoding, and the second MIMO distributed pilot encoding may be null pilot encoding.

[0101] At this time, at least one of the first polarization transmission signal and the second polarization transmission signal may include a preamble. At this time, the preamble may include a 1-bit L1B_mimo_scattered_pilot_encoding field set to 0.

[0102] At this time, the 1-bit L1B_mimo_scattered_pilot_encoding field set to 0 can indicate both a MIMO pilot pattern with Walsh-Hadamard encoding and the SISO pilot pattern simultaneously.

[0103] In this way, when considering a conventional single-antenna receiver in a broadcast signal transmitter that uses LDM and MIMO together, a collision may occur between the pilot pattern for the MIMO terminal and the pilot pattern for the SISO terminal (between the signaling information of the pilot pattern for the MIMO terminal and the signaling information of the pilot pattern for the SISO terminal).

[0104] In the ATSC 3.0 broadcast system, L1B_first_sub_scattered_pilot_pattern (for the first subframe) and L1D_scattered_pilot_pattern (for other subframes) are used as scattered pilot pattern identification fields, and the scattered pilot pattern is signaled through these fields.

[0105] These fields are signaling fields commonly used for SISO transmission and MIMO transmission, and the receiver can distinguish whether it is a SISO distributed pilot pattern or a MIMO distributed pilot pattern by combining these fields with other MIMO-related fields (e.g., L1B_first_sub_mimo (for the first subframe) and L1D_mimo (for other subframes)) and then find out the exact distributed pilot pattern.

[0106] At this time, L1B_first_sub_mimo and L1D_mimo can indicate whether MIMO transmission is applied to the corresponding subframe.

[0107] That is, even if L1B_first_sub_scattered_pilot_pattern or L1D_scattered_pilot_pattern has the same value, depending on whether it is SISO transmission or MIMO transmission, the scattered pilot pattern may be interpreted as a SISO pattern as shown in Table 1 below, or as a MIMO pattern as shown in Table 2 below.

[0108] ValueSP patternValueSP patternValueSP pattern00000SP3_201000SP12_210000Reserved00001SP3_401001SP12_4......00010SP4_201010SP16_2......00011SP4_401011SP16_4.. ....00100SP6_201100SP24_2......00101SP6_401101SP24_4......00110SP8_201110SP32_2......00111SP8_401111SP32_411111Reserved

[0109] Table 1 shows the signaling formats of L1D_scattered_pilot_pattern and L1B_first_sub_scattered_pilot_pattern for SISO.

[0110] ValueSP patternValueSP patternValueSP pattern00000MP3_201000MP12_210000Reserved00001MP3_401001MP12_4......00010MP4_201010MP16_2......00011MP4_401011MP16_4.. ....00100MP6_201100MP24_2......00101MP6_401101MP24_4......00110MP8_201110MP32_2......00111MP8_401111MP32_411111Reserved

[0111] Table 2 shows the signaling formats of L1D_scattered_pilot_pattern and L1B_first_sub_scattered_pilot_pattern for MIMO.

[0112] In Tables 1 and 2, SP represents SISO Pilot and MP represents MIMO Pilot.

[0113] Ultimately, when considering the existing SISO receiver and combining LDM and MIMO technologies to transmit SISO and MIMO signals in the same subframe, both the SISO receiver and the MIMO receiver must be able to simultaneously receive accurate scattered pilot pattern information through a common signaling field, L1B_first_sub_scattered_pilot_pattern or L1D_scattered_pilot_pattern. This means that L1B_first_sub_scattered_pilot_pattern or L1D_scattered_pilot_pattern must be compatible with both SISO and MIMO.

[0114] For example, if L1B_first_sub_scattered_pilot_pattern or L1D_scattered_pilot_pattern is 00000, the SISO receiver must perform channel estimation through SP3_2 in Table 1, and the MIMO receiver must perform channel estimation through MP3_2 in Table 2.

[0115] In order to receive a MIMO transmission signal, it is necessary to estimate the first polarization channel and the second polarization channel separately, and therefore, distinguishable pilot signals are transmitted to both the first polarization (first antenna) and the second polarization (second antenna).

[0116] The MIMO distributed pilot pattern used in ATSC 3.0 systems is defined using either Walsh-Hadamard encoding or null-pilot encoding.

[0117] The pilot pattern corresponding to Walsh-Hadamard encoding is such that both the first polarization and the second polarization transmit their respective pilots at the same OFDM cell locations. That is, Walsh-Hadamard encoding designs the sequences corresponding to the pilots for the first polarization and the sequences corresponding to the pilots for the second polarization to be orthogonal, so that only the corresponding pilots can be extracted from each transmission channel.

[0118] The pilot pattern corresponding to the null pilot encoding is such that the second polarization is muted at the position where the first polarization transmits the pilot, and the first polarization is muted at the position where the second polarization transmits the pilot.

[0119] Comparing the SISO distributed pilot pattern, the MIMO Walsh-Hadamard distributed pilot pattern, and the MIMO null-pilot distributed pilot pattern signaled with the same 5-bit value in Tables 1 and 2 above, the following relationship can be confirmed.

[0120] The first polarization (first antenna) portion of the MIMO Walsh-Hadamard distributed pilot pattern transmits pilot signals identical to the SISO distributed pilot pattern to the same OFDM cell location.

[0121] The first polarization (first antenna) portion of the MIMO null-pilot distributed pilot pattern transmits pilot signals at only half of the pilot positions of the SISO distributed pilot pattern.

[0122] This relationship can be summarized as shown in Table 3 below.

[0123] Pilot EncodingAlgorithmAntennaScatteredPilotSubframeBoundaryPilotCommonContinualPilotAdditionalContinualPilotEdgePilotWalsh-Hadamard#1SISOSISOSISOSISOSISO#2WHWHSISOSISO / WHWHNull Pilot#1NPSISOSISOSISO / NPSISO#2NPWHSISOSISO / NPWH

[0124] In Table 3, WH represents Walsh-Hadamard and NP represents Null Pilot.

[0125] Figures 5, 6 and 7 illustrate SISO scattered pilot patterns, MIMO Walsh-Hadamard scattered pilot patterns and MIMO null-pilot scattered pilot patterns when 5-bit L1B_first_sub_scattered_pilot_pattern or L1D_scattered_pilot_pattern is 00000.

[0126] Figure 5 is a diagram showing an example of a SISO distributed pilot pattern corresponding to SP3_2.

[0127] Referring to Figure 5, D for SISO X = 3 and D Y = You can find out the pilot positions in case 2.

[0128] FIG. 6 is a diagram showing an example of a Walsh-Hadamard encoded MIMO distributed pilot pattern corresponding to MP3_2.

[0129] Referring to FIG. 6, it can be seen that the OFDM cell locations of the SISO distributed pilot pattern corresponding to SP3_2 and the OFDM cell locations of the Walsh-Hadamard encoded MIMO distributed pilot pattern corresponding to MP3_2 are basically the same.

[0130] The Walsh-Hadamard encoded MIMO distributed pilot pattern illustrated in FIG. 6 transmits the same pilots as illustrated in FIG. 5 in both group 1 positions and group 2 positions for the first polarization. At this time, for the second polarization, the same pilots as those for the first polarization are transmitted in group 1 positions, and pilots that are opposite in phase to the pilots for the first polarization are transmitted in group 2 positions.

[0131] That is, in the Walsh-Hadamard encoded MIMO distributed pilot pattern illustrated in FIG. 6, the same pilots as the SISO distributed pilot pattern illustrated in FIG. 5 are transmitted in the first polarization, and in the second polarization, only some pilots are transmitted with their phases reversed at the same positions as the SISO distributed pilot pattern illustrated in FIG. 5.

[0132] FIG. 7 is a diagram showing an example of a null pilot encoded MIMO distributed pilot pattern corresponding to MP3_2.

[0133] Referring to FIG. 7, it can be seen that the OFDM cell locations of the Walsh-Hadamard encoded MIMO distributed pilot pattern corresponding to MP3_2 are basically the same as the OFDM cell locations of the null-pilot encoded MIMO distributed pilot pattern corresponding to MP3_2, except for the grouping.

[0134] However, the null-pilot encoded MIMO distributed pilot pattern illustrated in FIG. 7 transmits pilots only at group 1 positions for the first polarization, and transmits pilots only at group 2 positions for the second polarization.

[0135] That is, the null-pilot encoded MIMO distributed pilot pattern illustrated in FIG. 7 transmits pilot signals only at half of the pilot positions (group 1 positions) of the SISO distributed pilot pattern distributed pilot pattern illustrated in FIG. 5 in the first polarization. Similarly, the null-pilot encoded MIMO distributed pilot pattern transmits pilot signals only at the other half of the pilot positions (group 2 positions) of the SISO distributed pilot pattern distributed pilot pattern illustrated in FIG. 5 in the second polarization.

[0136] In a broadcast signal transmission / reception system combining LDM and MIMO, the core layer and the enhanced layer may need to use the same pilot signal to prevent increased receiver complexity and reduce the burden of receiver memory usage.

[0137] The broadcast signal transmitter having the structure described through FIGS. 3 and 4 transmits a broadcast signal combining SISO and MIMO, taking into account a conventional single-antenna receiver, and the single-antenna receiver can only receive the first polarization signal. In such an environment, if a null pilot pattern is applied as a distributed pilot pattern, the SISO receiver will use the interference signal transmitted in the second polarization for pilot-based channel estimation using the corresponding PLP (Physical Layer Pipe), which may result in misestimation.

[0138] Meanwhile, when transmitting a broadcast signal combining SISO and MIMO by combining LDM and MIMO technologies, if a null-pilot pattern is applied, a conflict may occur with the L1-basic and L1-detail signaling for the existing SISO service.

[0139] The existing ATSC 3.0 broadcast system sets the L1B_mimo_scattered_pilot_encoding field (L1-Basic signaling field) to 0 in the following two cases.

[0140] - When the Walsh-Hadamard pilot pattern is used

[0141] - If there is no subframe with MIMO applied within the transmission frame

[0142] When receiving a subframe that combines SISO and MIMO by combining LDM and MIMO technologies, it may be desirable for the SISO receiver to be unaware of the presence of the enhanced layer transmitted in the form of MIMO. Therefore, in this case, L1B_first_sub_mimo (for the first subframe) or L1D_mimo (for other subframes) should be set to 0. In this case, L1B_first_sub_mimo and L1D_mimo may be fields indicating whether MIMO is applied to the corresponding subframe (in principle, they are set to 1 if MIMO is applied). In this way, even though MIMO is applied to the enhanced layer, if L1B_first_sub_mimo (for the first subframe) or L1D_mimo (for other subframes) is set to 0, the MIMO receiver may operate based on other MIMO-related fields other than these fields to identify the MIMO pilot pattern.

[0143] When the core layer transmits a SISO signal and only the enhanced layer applies MIMO, there may be no MIMO subframes in the transmission frame other than the subframes in which SISO and MIMO are combined with LDM, and there may be MIMO subframes in the transmission frame other than the subframes in which SISO and MIMO are combined with LDM.

[0144] If there are no MIMO subframes in a transmission frame other than the subframes in which SISO and MIMO are combined with LDM, and a null-pilot pattern is applied to the subframes in which SISO and MIMO are combined with LDM, and L1B_mimo_scattered_pilot_encoding must be set to 1, then this is not desirable because it causes a conflict with L1B_first_sub_mimo or L1D_mimo set to 0 in the received preamble from the perspective of the existing SISO receiver.

[0145] In the case where a MIMO subframe exists in a transmission frame other than the subframes in which SISO and MIMO are LDM-combined, a signaling collision may not occur if other MIMO subframes in the transmission frame apply the null pilot pattern. However, even in this case, considering the situation where a single scattered pilot pattern identification field (L1B_first_sub_scattered_pilot_pattern or L1D_scattered_pilot_pattern) is shared by the SISO receiver and the MIMO receiver, it is desirable to prohibit the use of the null pilot pattern and use only the Walsh-Hadamard pilot pattern. In this case, the Walsh-Hadamard pilot pattern may be applied to the enhanced layer of the broadcast signal transmission device of FIGS. 3 and 4 regardless of the value signaled in L1B_mimo_scattered_pilot_encoding.

[0146] Ultimately, when transmitting a broadcast signal combining SISO and MIMO by combining LDM and MIMO technologies, only Walsh-Hadamard encoding among null-pilot encoding and Walsh-Hadamard encoding can be allowed as pilot encoding.

[0147] At this time, the 1-bit signaling field L1B_mimo_scattered_pilot_encoding can be set to 0, which can indicate both a MIMO pilot pattern with Walsh-Hadamard encoding and the SISO pilot pattern simultaneously.

[0148] The core layer and the enhanced layer can share pilots not only when MIMO is applied to both the core layer and the enhanced layer, but also when SISO is applied to the core layer and MIMO is applied only to the enhanced layer.

[0149] FIG. 8 is a diagram showing an example of a transmission signal configuration when a SISO signal is transmitted only through one of two MIMO antennas.

[0150] Referring to FIG. 8, it can be seen that in the first polarization (V-POL), the core layer signal and the enhanced layer signal are transmitted together, and in the second polarization (H-POL), only the enhanced layer signal is transmitted.

[0151] The example illustrated in Fig. 8 is an example in which the Walsh-Hadamard pilot pattern is applied, and it can be seen that the distributed pilot pattern is applied equally to the core layer and the enhanced layer in the first polarization (V-POL). In the example illustrated in Fig. 8, the phases of the pilots of some cell positions in the second polarization (H-POL) are opposite to those of the pilots in the first polarization.

[0152] FIG. 9 is a diagram showing an example of a transmission signal configuration when a SISO signal is transmitted through both MIMO antennas.

[0153] Referring to FIG. 9, it can be seen that the core layer signal and the enhanced layer signal are transmitted together in the first polarization (V-POL) and the second polarization (H-POL).

[0154] The example illustrated in Fig. 9 is an example in which the Walsh-Hadamard pilot pattern is applied. It can be seen that the distributed pilot pattern is applied equally to the core layer and the enhanced layer in the first polarization (V-POL) and the second polarization (H-POL). In the example illustrated in Fig. 9, the phases of the pilots of some cell positions in the second polarization (H-POL) are opposite to those of the pilots in the first polarization.

[0155] Figure 10 is a diagram comparing a SISO distributed pilot pattern and a MIMO distributed pilot pattern.

[0156] Referring to Fig. 10, it can be seen that in the first polarization (V-POL), the Walsh-Hadamard encoded MP3_2 MIMO distributed pilot pattern is completely identical to the SISO SP3_2 distributed pilot pattern. In the second polarization (H-POL), the phases of the pilots at the pilot positions corresponding to the second group are inverted.

[0157] Figure 11 is a flowchart illustrating a broadcast signal transmission method according to one embodiment of the present invention.

[0158] Referring to FIG. 11, a broadcast signal transmission method according to an embodiment of the present invention generates a core layer signal (SISO signal) (S1110).

[0159] In addition, a broadcast signal transmission method according to one embodiment of the present invention generates enhanced layer MIMO (Multiple Input Multiple Output) signals (S1120).

[0160] In addition, a broadcast signal transmission method according to an embodiment of the present invention hierarchically multiplexes one of the core layer signal and the enhanced layer MIMO signals to output a first polarization signal corresponding to the first polarization, and outputs another one of the enhanced layer MIMO signals as a second polarization signal corresponding to the second polarization (S1130).

[0161] In addition, a broadcast signal transmission method according to one embodiment of the present invention generates a first polarization transmission signal using the first polarization signal and a second polarization transmission signal using the second polarization signal (S1140).

[0162] At this time, in the first polarization, at least one SISO (Single Input Single Output) PLP (Physical Layer Pipe) and at least one MIMO PLP superposed with the at least one SISO PLP can share pilot cells.

[0163] At this time, the first polarization transmission signal and the second polarization transmission signal can be generated using only the first MIMO distributed pilot encoding among the first MIMO distributed pilot encoding that transmits pilots to the same OFDM cell positions for the first polarization and the second polarization, and the second MIMO distributed pilot encoding that transmits pilots to different OFDM cell positions for the first polarization and the second polarization.

[0164] At this time, the first MIMO distributed pilot encoding may correspond to a first group in which identical pilots are transmitted for the first polarization and the second polarization, and a second group in which pilots with opposite phases are transmitted for the first polarization and the second polarization.

[0165] At this time, the second MIMO distributed pilot encoding may correspond to a first group in which only pilots for the first polarization are transmitted with valid power and pilots for the second polarization are transmitted with null power, and a second group in which only pilots for the second polarization are transmitted with valid power and pilots for the first polarization are transmitted with null power.

[0166] At this time, the first MIMO distributed pilot encoding may be Walsh-Hadamard encoding, and the second MIMO distributed pilot encoding may be null pilot encoding.

[0167] At this time, at least one of the first polarization transmission signal and the second polarization transmission signal may include a preamble. At this time, the preamble may include a 1-bit L1B_mimo_scattered_pilot_encoding field (L1-Basic signaling field) set to 0.

[0168] At this time, the 1-bit L1B_mimo_scattered_pilot_encoding field set to 0 can indicate both a MIMO pilot pattern with Walsh-Hadamard encoding and the SISO pilot pattern simultaneously.

[0169] Figure 12 is a flowchart illustrating a broadcast signal receiving method according to one embodiment of the present invention.

[0170] Referring to FIG. 12, a broadcast signal receiving method according to one embodiment of the present invention receives a broadcast signal including a preamble (S1210).

[0171] In addition, a broadcast signal receiving method according to an embodiment of the present invention restores a 1-bit L1B_mimo_scattered_pilot_encoding field and a scattered pilot pattern identification field included in the preamble (S1220).

[0172] At this time, the scattered pilot pattern identification field can be a 5-bit signaling field, L1B_first_sub_scattered_pilot_pattern (for the first subframe) or L1D_scattered_pilot_pattern (for other subframes).

[0173] At this time, the distributed pilot pattern identification field can be shared with a SISO (Single Input Single Output) receiver and a MIMO (Multiple Input Multiple Output) receiver.

[0174] At this time, the MIMO receiver can receive pilot cells shared by at least one SISO PLP (Physical Layer Pipe) and at least one MIMO PLP superposed with the at least one SISO PLP in the first polarization.

[0175] At this time, the L1B_mimo_scattered_pilot_encoding field may be set to 0 to indicate both a MIMO pilot pattern with Walsh-Hadamard encoding and the SISO pilot pattern simultaneously.

[0176] In addition, a broadcast signal receiving method according to one embodiment of the present invention identifies a distributed pilot pattern using the distributed pilot pattern identification field (S1230).

[0177] In addition, a broadcast signal receiving method according to one embodiment of the present invention performs channel estimation based on the identified distributed pilot pattern (S1240).

[0178] Each step illustrated in FIGS. 11 and 12 may be performed in the order illustrated in FIGS. 11 and 12, in the reverse order, or simultaneously.

[0179] Figure 13 is a block diagram showing a computer system configuration according to one embodiment of the present invention.

[0180] The broadcast signal transmitting device, the broadcast signal receiving device and the individual components constituting these devices according to the embodiment can be implemented in a computer system (1300).

[0181] The computer system (1300) may include one or more processors (1310), memory (1330), user interface input devices (1340), user interface output devices (1350), and storage (1360) that communicate with each other via a bus (1320). In addition, the computer system (1300) may further include a network interface (1370) connected to a network (1380). The processor (1310) may be a central processing unit or a semiconductor device that executes programs or processing instructions stored in the memory (1330) or storage (1360). The memory (1330) and storage (1360) may be storage media that include at least one of a volatile medium, a nonvolatile medium, a removable medium, a non-removable medium, a communication medium, or an information transmission medium. For example, the memory (1330) may include a ROM (1331) or a RAM (1332).

[0182] At this time, at least one program can be recorded in the memory (1330).

[0183] At this time, the processor (1310) can execute the program. At this time, the program can perform each step illustrated in FIG. 11 or each step illustrated in FIG. 12.

[0184]

[0185] As described above, the broadcast signal transmission device, method, and broadcast signal reception method according to the present invention are not limited to the configurations and methods of the embodiments described above, but the embodiments may be configured by selectively combining all or part of the embodiments so that various modifications can be made.

Claims

1. A core layer signal generation unit that generates a core layer signal; An enhanced layer MIMO signal generation unit that generates enhanced layer MIMO (Multiple Input Multiple Output) signals; An LDM combiner that hierarchically multiplexes one of the core layer signal and the enhanced layer MIMO signals to output a first polarization signal corresponding to the first polarization, and outputs the other one of the enhanced layer MIMO signals as a second polarization signal corresponding to the second polarization; and A transmission signal generation unit that generates a first polarization transmission signal using the first polarization signal and a second polarization transmission signal using the second polarization signal. A broadcast signal transmitting device including:

2. In claim 1, In the above first polarization A broadcast signal transmission device, wherein at least one SISO (Single Input Single Output) PLP (Physical Layer Pipe) and at least one MIMO PLP superposed with the at least one SISO PLP share pilot cells.

3. In claim 2, The first polarization transmission signal and the second polarization transmission signal are A first MIMO distributed pilot encoding that transmits pilots to the same OFDM cell positions for the first polarization and the second polarization, and Among the second MIMO distributed pilot encodings that transmit pilots to different OFDM cell positions for the first polarization and the second polarization, A broadcast signal transmission device generated using only the first MIMO distributed pilot encoding.

4. In claim 3, The above first MIMO distributed pilot encoding is A broadcast signal transmitting device, corresponding to a first group in which identical pilots are transmitted for the first polarization and the second polarization, and a second group in which pilots with opposite phases are transmitted for the first polarization and the second polarization.

5. In claim 4, The above second MIMO distributed pilot encoding is A broadcast signal transmitting device, corresponding to a first group in which only pilots for the first polarization are transmitted with valid power and pilots for the second polarization are transmitted with null power, and a second group in which only pilots for the second polarization are transmitted with valid power and pilots for the first polarization are transmitted with null power.

6. In claim 3, A broadcast signal transmission device, wherein the first MIMO distributed pilot encoding is Walsh-Hadamard encoding, and the second MIMO distributed pilot encoding is null pilot encoding.

7. In claim 6, At least one of the first polarization transmission signal and the second polarization transmission signal includes a preamble, The above preamble is A broadcast signal transmitting device comprising a 1-bit L1B_mimo_scattered_pilot_encoding field set to 0.

8. In claim 7, A broadcast signal transmitting device, wherein the 1-bit L1B_mimo_scattered_pilot_encoding field set to 0 indicates both a MIMO pilot pattern with Walsh-Hadamard encoding and the SISO pilot pattern simultaneously.

9. Step of generating core layer signal; A step of generating enhanced layer MIMO (Multiple Input Multiple Output) signals; A step of hierarchically multiplexing one of the core layer signal and the enhanced layer MIMO signals to output a first polarization signal corresponding to the first polarization, and outputting the other one of the enhanced layer MIMO signals as a second polarization signal corresponding to the second polarization; and A step of generating a first polarization transmission signal using the first polarization signal and a second polarization transmission signal using the second polarization signal. A method for transmitting a broadcast signal including:

10. In claim 9, In the above first polarization A method for transmitting a broadcast signal, wherein at least one SISO (Single Input Single Output) PLP (Physical Layer Pipe) and at least one MIMO PLP superposed with the at least one SISO PLP share pilot cells.

11. In claim 10, The first polarization transmission signal and the second polarization transmission signal are A first MIMO distributed pilot encoding that transmits pilots to the same OFDM cell positions for the first polarization and the second polarization, and Among the second MIMO distributed pilot encodings that transmit pilots to different OFDM cell positions for the first polarization and the second polarization, A method for transmitting a broadcast signal, generated using only the first MIMO distributed pilot encoding.

12. In claim 11, The above first MIMO distributed pilot encoding is A method for transmitting broadcast signals, wherein the first group is transmitted with identical pilots for the first polarization and the second polarization, and the second group is transmitted with pilots with opposite phases for the first polarization and the second polarization.

13. In claim 12, The above second MIMO distributed pilot encoding is A method for transmitting broadcast signals, wherein a first group in which only pilots for the first polarization are transmitted with valid power and pilots for the second polarization are transmitted with null power, and a second group in which only pilots for the second polarization are transmitted with valid power and pilots for the first polarization are transmitted with null power.

14. In claim 11, A method for transmitting a broadcast signal, wherein the first MIMO distributed pilot encoding is Walsh-Hadamard encoding, and the second MIMO distributed pilot encoding is null pilot encoding.

15. In claim 14, At least one of the first polarization transmission signal and the second polarization transmission signal includes a preamble, The above preamble is A method for transmitting a broadcast signal, comprising a 1-bit L1B_mimo_scattered_pilot_encoding field set to 0.

16. In claim 15, A method for transmitting a broadcast signal, wherein the 1-bit L1B_mimo_scattered_pilot_encoding field set to 0 indicates both a MIMO pilot pattern with Walsh-Hadamard encoding and the SISO pilot pattern simultaneously.

17. A step of receiving a broadcast signal including a preamble; A step of restoring a 1-bit L1B_mimo_scattered_pilot_encoding field and a scattered pilot pattern identification field included in the above preamble; A step of identifying a distributed pilot pattern using the above distributed pilot pattern identification field; and A step of performing channel estimation based on the identified distributed pilot pattern. A method for receiving a broadcast signal, comprising:

18. In claim 17, The above distributed pilot pattern identification field is A method for receiving a broadcast signal shared by a SISO (Single Input Single Output) receiver and a MIMO (Multiple Input Multiple Output) receiver.

19. In claim 17, A method for receiving a broadcast signal, wherein the above L1B_mimo_scattered_pilot_encoding field is set to 0 to indicate both a MIMO pilot pattern with Walsh-Hadamard encoding and the SISO pilot pattern simultaneously.

20. In claim 19, The above MIMO receiver A method for receiving a broadcast signal, comprising receiving pilot cells shared by at least one SISO PLP (Physical Layer Pipe) and at least one MIMO PLP superposed with the at least one SISO PLP in a first polarization.

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