KR102459600B1 - Apparatus for broadcasting scalable video contents and method using the same - Google Patents

Abstract

Disclosed are an apparatus and method for broadcasting scalable video content using layered division multiplexing. A scalable video content broadcasting apparatus according to an embodiment of the present invention includes: a video codec unit that divides a codec media stream into a plurality of layers and generates a plurality of codec layer signals; an encapsulation and delivery unit that converts the codec layer signals for transmission; and a broadcast signal multiplexer configured to generate a layered division multiplexed broadcast signal by combining the plurality of codec layer signals at different power levels.

Description

Scalable video content broadcasting apparatus and method using the same

The present invention relates to a broadcast signal transmission/reception technology used in a broadcast system, and more particularly, to a broadcast signal transmission/reception system for effectively multiplexing and broadcasting hierarchical signals of scalable video content.

In order to simultaneously support multiple multiple services, multiplexing, which is a process of mixing multiple signals, is required. Among these multiplexing techniques, currently widely used techniques include Time Division Multiplexing (TDM) for dividing time resources and Frequency Division Multiplexing (FDM) for using dividing frequency resources. That is, TDM is a method of allocating divided time for each service, and FDM is a method of allocating and using divided frequency resources for each service. Recently, there is an urgent need for a new multiplexing technique that provides a higher level of flexibility and better performance than TDM and FDM applicable to a next-generation broadcasting system.

Meanwhile, research on a video codec technology for providing scalability such as scalable video coding (SVC) or scalable HEVC video coding (SHVC) is being actively conducted. .

An object of the present invention is to provide a more flexible and advanced broadcasting service to users by effectively multiplexing scalable video content using a video codec such as Scalable Video Coding (SVC) or Scalable-HEVC Video Coding (SHVC).

In addition, an object of the present invention is to combine a scalable video codec using SVC or HEVC with a transmission/reception technology based on Layered Division Multiplexing in a next-generation broadcasting system to achieve a high level of flexibility. and to provide excellent performance.

According to an aspect of the present invention, there is provided a scalable video content broadcasting apparatus comprising: a video codec unit that divides a codec media stream into a plurality of layers and generates a plurality of codec layer signals; an encapsulation and delivery unit that converts the codec layer signals for transmission; and a broadcast signal multiplexer configured to generate a layered division multiplexed broadcast signal by combining the plurality of codec layer signals at different power levels.

In this case, the codec layer signals may correspond 1:1 to the layers of the broadcast signal multiplexer.

In this case, the codec layer signals include a base layer signal and an enhancement layer signal, the base layer signal corresponds to a core layer signal of the broadcast signal multiplexing unit, and the enhancement layer signal is an enhanced layer signal of the broadcast signal multiplexing unit. It may correspond to a signal.

In this case, the broadcast signal multiplexing unit includes: a combiner for generating a multiplexed signal by combining the core layer signal and the enhanced layer signal at different power levels; a power normalizer for lowering the power of the multiplexed signal to a power corresponding to the core layer signal; a time interleaver configured to generate a time interleaved signal by performing interleaving applied to the core layer signal and the enhanced layer signal together; and a frame builder that generates a broadcast signal frame corresponding to the layered division multiplexed broadcast signal by using the time interleaved signal and the L1 signaling information.

In this case, the broadcast signal multiplexing unit further includes an injection level controller configured to generate a power-reduced enhanced layer signal by reducing the power of the enhanced layer signal, and the combiner includes the core layer signal and the power-reduced enhanced layer signal. The multiplexed signal may be generated by combining the layer signals.

In this case, the broadcast signal multiplexing unit includes a core layer BICM unit corresponding to the core layer signal; and an enhanced layer BICM unit that performs BICM encoding different from the core layer BICM unit.

In this case, the power normalizer may lower the power of the multiplexed signal by the amount increased by the combiner corresponding to the normalizing factor.

In this case, the injection level controller corresponds to the scaling factor, the normalizing factor and the scaling factor are each greater than 0 and less than 1, and the scaling factor decreases as the power reduction corresponding to the injection level controller increases, and the The normalizing factor may increase as the power reduction corresponding to the injection level controller increases.

In this case, the enhanced layer signal may correspond to the enhanced layer data restored based on cancellation corresponding to the restoration of the core layer data corresponding to the core layer signal.

In this case, the combiner may combine the core layer signal and one or more extension layer signals having a lower power level than the enhanced layer signal together with the core layer signal and the enhanced layer signal.

In this case, the codec layer signals may further include an additional enhancement layer signal, and the additional enhancement layer signal may correspond to the extension layer signal.

In this case, the codec layer signals include a base layer signal and two or more enhancement layer signals, the base layer signal corresponds to a core layer signal of the broadcast signal multiplexer, and the enhancement layer signals are enhanced by the broadcast signal multiplexer. It may correspond to a de-layer signal.

In this case, the enhancement layer signals may be multiplexed using a multiplexer provided in the broadcast signal multiplexer to correspond to the enhanced layer signal.

In addition, a method for broadcasting scalable video content according to an embodiment of the present invention includes generating a plurality of codec layer signals by dividing a codec media stream into a plurality of layers; performing transformation for transmission on the codec layer signals; and combining the plurality of codec layer signals at different power levels to generate a layered division multiplexed broadcast signal.

In this case, the codec layer signals may correspond to the layers of the layered division multiplexing 1:1.

In this case, the codec layer signals include a base layer signal and an enhancement layer signal, the base layer signal corresponds to the core layer signal of the layered division multiplexing, and the enhancement layer signal is the enhanced layer of the layered division multiplexing It may correspond to a signal.

In this case, the generating of the broadcast signal may include: generating a multiplexed signal by combining the core layer signal and the enhanced layer signal at different power levels; lowering the power of the multiplexed signal to a power corresponding to the core layer signal; generating a time interleaved signal by performing interleaving applied to the core layer signal and the enhanced layer signal together; and generating a broadcast signal frame corresponding to the layered division multiplexed broadcast signal by using the time interleaved signal and the L1 signaling information.

At this time, the generating of the multiplexed signal may include combining the core layer signal and one or more extension layer signals of a lower power level than the enhanced layer signal with the core layer signal and the enhanced layer signal. can

In this case, the codec layer signals may further include an additional enhancement layer signal, and the additional enhancement layer signal may correspond to the extension layer signal.

In this case, the codec layer signals include a base layer signal and two or more enhancement layer signals, the base layer signal corresponds to the core layer signal of the layered division multiplexing, and the enhancement layer signals are the enhancement layer signals of the layered division multiplexing. It may correspond to a de-layer signal.

According to the present invention, it is possible to effectively multiplex scalable video content using a video codec such as Scalable Video Coding (SVC) or Scalable-HEVC Video Coding (SHVC) to provide users with a more flexible and advanced broadcasting service.

In addition, the present invention combines a scalable video codec using SVC or HEVC and a transmission/reception technology based on Layered Division Multiplexing in a next-generation broadcasting system to provide a high level of flexibility and excellent performance can be provided.

1 is a block diagram illustrating a broadcast signal transmission/reception system according to an embodiment of the present invention.
2 is an operation flowchart illustrating a broadcast signal transmission/reception method according to an embodiment of the present invention.
FIG. 3 is a block diagram illustrating an example of the signal multiplexing apparatus shown in FIG. 1 .
4 is a diagram illustrating an example of a broadcast signal frame structure.
FIG. 5 is a block diagram illustrating another example of the signal multiplexing apparatus shown in FIG. 1 .
6 is a block diagram illustrating an example of the signal demultiplexing apparatus shown in FIG. 1 .
7 is a block diagram illustrating an example of the core layer BICM decoder and the enhanced layer symbol extractor shown in FIG. 6 .
8 is a block diagram illustrating another example of the core layer BICM decoder and the enhanced layer symbol extractor shown in FIG. 6 .
9 is a block diagram illustrating another example of the core layer BICM decoder and the enhanced layer symbol extractor shown in FIG. 6 .
FIG. 10 is a block diagram illustrating another example of the signal demultiplexing apparatus shown in FIG. 1 .
11 is a diagram illustrating a power increase due to a combination of a core layer signal and an enhanced layer signal.
12 is a flowchart illustrating a signal multiplexing method according to an embodiment of the present invention.
13 is a block diagram illustrating a scalable video content broadcasting apparatus according to an embodiment of the present invention.
14 is a diagram illustrating an example of codec layer signals.
FIG. 15 is a diagram illustrating a transmission signal spectrum of the scalable video content broadcasting apparatus shown in FIG. 13 .
16 is a block diagram illustrating a scalable video content broadcasting apparatus according to another embodiment of the present invention.
17 is a diagram illustrating another example of codec layer signals.
18 is a diagram illustrating a transmission signal spectrum of the scalable video content broadcasting apparatus shown in FIG. 16 .
19 is a diagram illustrating a transmission signal spectrum when two enhancement layer signals are mapped to one enhanced layer.
20 is a flowchart illustrating a method for broadcasting scalable video content according to an embodiment of the present invention.

The present invention will be described in detail with reference to the accompanying drawings as follows. Here, repeated descriptions, well-known functions that may unnecessarily obscure the gist of the present invention, and detailed descriptions of configurations will be omitted. The embodiments of the present invention are provided in order to more completely 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 clearer description.

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram illustrating a broadcast signal transmission/reception system according to an embodiment of the present invention.

Referring to FIG. 1 , a broadcast signal transmission/reception system according to an embodiment of the present invention includes a broadcast signal transmission device 110 , a wireless channel 120 , and a broadcast signal reception device 130 .

The broadcast signal transmission apparatus 110 includes a signal multiplexing apparatus 111 for multiplexing core layer data and enhanced layer data and an OFDM transmitter 113 .

The signal multiplexing device 111 combines the core layer signal corresponding to the core layer data and the enhanced layer signal corresponding to the enhanced layer data at different power levels, and is combined with the core layer signal and the enhanced layer signal. A multiplexed signal is generated by performing applied interleaving. In this case, the signal multiplexing apparatus 111 may generate a broadcast signal frame using the time-interleaved signal and the L1 signaling information. In this case, the broadcast signal frame may be an ATSC 3.0 frame.

The OFDM transmitter 113 transmits the multiplexed signal through the antenna 117 using the OFDM communication method so that the transmitted OFDM signal is transmitted through the antenna 137 of the broadcast signal receiving apparatus 130 through the wireless channel 120 . to be received

The broadcast signal receiving apparatus 130 includes an OFDM receiver 133 and a signal demultiplexing apparatus 131 . When a signal transmitted through the wireless channel 120 is received through the antenna 137, the OFDM receiver 133 receives the OFDM signal through synchronization, channel estimation, and equalization. do.

The signal demultiplexing apparatus 131 first restores core layer data from a signal received through the OFDM receiver 133 , and restores enhanced layer data through cancellation corresponding to the restored core layer data. In this case, the signal demultiplexing apparatus 131 may first generate a broadcast signal frame, restore the L1 signaling information from the broadcast signal frame, and then use the L1 signaling information to restore the data signal. In this case, the L1 signaling information may include injection level information, normalizing factor information, and the like.

As will be described later, the signal multiplexing apparatus 111 shown in FIG. 1 includes: a combiner for generating a multiplexed signal by combining a core layer signal and an enhanced layer signal with different power levels; a power normalizer for lowering the power of the multiplexed signal to a power corresponding to the core layer signal; a time interleaver configured to generate a time interleaved signal by performing interleaving applied to the core layer signal and the enhanced layer signal together; and a frame builder that generates a broadcast signal frame by using the time-interleaved signal and L1 signaling information. At this time, the broadcast signal transmission apparatus 110 shown in FIG. 1 includes: a combiner for generating a multiplexed signal by combining a core layer signal and an enhanced layer signal with different power levels; a power normalizer for lowering the power of the multiplexed signal to a power corresponding to the core layer signal; a time interleaver configured to generate a time interleaved signal by performing interleaving applied to the core layer signal and the enhanced layer signal together; a frame builder for generating a broadcast signal frame by using the time-interleaved signal and L1 signaling information; and an OFDM transmitter that transmits the broadcast signal frame through an antenna using an OFDM communication scheme.

As will be described later, the signal demultiplexing apparatus shown in FIG. 1 includes: a time deinterleaver configured to generate a time deinterleaving signal by applying time deinterleaving to a received signal; a de-normalizer that increases the power of the received signal or the time deinterleaving signal by a power reduction by a power normalizer of a transmitter; a core layer BICM decoder for reconstructing core layer data from the signal whose power is adjusted by the de-normalizer; Enhancement for extracting an enhanced layer signal by performing cancellation corresponding to the core layer data on the signal whose power is adjusted by the de-normalizer using the output signal of the core layer FEC decoder of the core layer BICM decoder de layer symbol extractor; a de-injection level controller that increases the power of the enhanced layer signal by a decrease in the power of the injection level controller of the transmitter; and an enhanced layer BICM decoder that reconstructs enhanced layer data using an output signal of the de-injection level controller. At this time, the broadcast signal receiving apparatus 130 shown in FIG. 1 includes an OFDM receiver that generates a received signal by performing any one or more of synchronization, channel estimation, and equalization on the transmitted signal; a time deinterleaver for generating a time deinterleaving signal by applying time deinterleaving to the received signal; a de-normalizer that increases the power of the received signal or the time deinterleaving signal by a power reduction by a power normalizer of a transmitter; a core layer BICM decoder for reconstructing core layer data from the signal whose power is adjusted by the de-normalizer; Enhancement for extracting an enhanced layer signal by performing cancellation corresponding to the core layer data on the signal whose power is adjusted by the de-normalizer using the output signal of the core layer FEC decoder of the core layer BICM decoder de layer symbol extractor; a de-injection level controller that increases the power of the enhanced layer signal by a decrease in the power of the injection level controller of the transmitter; and an enhanced layer BICM decoder for reconstructing enhanced layer data using an output signal of the de-injection level controller.

Although not explicitly shown in FIG. 1 , the broadcast signal transmission/reception system according to an embodiment of the present invention may multiplex/demultiplex one or more extension layer data in addition to the core layer data and the enhanced layer data. In this case, the extension layer data may be multiplexed at a lower power level than the core layer data and the enhanced layer data. Furthermore, when two or more extension layers are included, the injection power level of the second extension layer is lower than the injection power level of the first extension layer, and the injection power level of the third extension layer is lower than the injection power level of the second extension layer. can

2 is an operation flowchart illustrating a broadcast signal transmission/reception method according to an embodiment of the present invention.

Referring to FIG. 2 , in the method for transmitting/receiving a broadcast signal according to an embodiment of the present invention, a core layer signal and an enhanced layer signal are combined at different power levels and multiplexed (S210).

In this case, the multiplexed signal generated by step S210 may include a data signal and L1 signaling information. In this case, the L1 signaling information may include injection level information and normalizing factor information.

In addition, in the broadcast signal transmission/reception method according to an embodiment of the present invention, the multiplexed signal is OFDM transmitted ( S220 ).

In addition, in the broadcast signal transmission/reception method according to an embodiment of the present invention, the transmitted signal is OFDM received (S230).

In this case, in step S230, synchronization, channel estimation, and equalization may be performed.

In addition, in the broadcast signal transmission/reception method according to an embodiment of the present invention, core layer data is restored from the received signal (S240).

In addition, the broadcast signal transmission/reception method according to an embodiment of the present invention restores enhanced layer data through core layer signal cancellation (S250).

In particular, steps S240 and S250 shown in FIG. 2 may correspond to the demultiplexing operation corresponding to step S210.

As will be described later, the step S210 illustrated in FIG. 2 includes generating a multiplexed signal by combining the core layer signal and the enhanced layer signal at different power levels; lowering the power of the multiplexed signal to a power corresponding to the core layer signal; generating a time interleaved signal by performing interleaving applied to the core layer signal and the enhanced layer signal together; and generating a broadcast signal frame using the time-interleaved signal and L1 signaling information. In this case, the broadcast signal transmission method of step S210 includes: generating a multiplexed signal by combining a core layer signal and an enhanced layer signal at different power levels; lowering the power of the multiplexed signal to a power corresponding to the core layer signal; generating a time interleaved signal by performing interleaving applied to the core layer signal and the enhanced layer signal together; generating a broadcast signal frame using the time-interleaved signal and L1 signaling information; and transmitting the broadcast signal frame through an antenna using an OFDM communication method.

As will be described later, the steps S240 and S250 shown in FIG. 2 include generating a time deinterleaving signal by applying time deinterleaving to a received signal; increasing the power of the received signal or the time deinterleaving signal by a power reduction by a power normalizer of a transmitter; restoring core layer data from the power-adjusted signal; extracting an enhanced layer signal by performing cancellation corresponding to the core layer data on the power-adjusted signal; increasing the power of the enhanced layer signal by a power decrease of an injection level controller of the transmitter; and restoring enhanced layer data using the power-adjusted enhanced layer signal. In this case, a method for receiving a broadcast signal according to an embodiment of the present invention includes generating a received signal by performing any one or more of synchronization, channel estimation, and equalization on a transmitted signal; generating a time deinterleaving signal by applying time deinterleaving to the received signal; increasing the power of the received signal or the time deinterleaving signal by a power reduction by a power normalizer of a transmitter; restoring core layer data from the power-adjusted signal; extracting an enhanced layer signal by performing cancellation corresponding to the core layer data on the power-adjusted signal; increasing the power of the enhanced layer signal by a power decrease of an injection level controller of the transmitter; and restoring enhanced layer data using the power-adjusted enhanced layer signal.

FIG. 3 is a block diagram illustrating an example of the signal multiplexing apparatus shown in FIG. 1 .

Referring to FIG. 3 , the signal multiplexing apparatus according to an embodiment of the present invention includes a core layer BICM unit 310 , an enhanced layer BICM unit 320 , an injection level controller 330 , a combiner 340 , and a power normalizer. 345 , a time interleaver 350 , an L1 signaling generator 360 , and a frame builder 370 .

In general, a bit-interleaved coded modulation (BICM) device includes an error correction encoder, a bit interleaver, and a symbol mapper, and the core layer BICM unit 310 and the enhanced layer BICM unit 320 shown in FIG. It may include a correction encoder, a bit interleaver and a symbol mapper. In particular, the error correction encoders (CORE LAYER FEC ENCODER, ENHANCED LAYER FEC ENCODER) shown in FIG. 3 may be a serial combination of a BCH encoder and an LDPC encoder, respectively. In this case, the input of the error correction encoder may be input to the BCH encoder, the output of the BCH encoder may be input to the LDPC encoder, and the output of the LDPC encoder may be the output of the error correction encoder.

As shown in FIG. 3 , the core layer data and the enhanced layer data pass through different BICM units and are then combined through a combiner 340 . That is, in the present invention, layered division multiplexing (LDM) may mean transmitting a plurality of layers by combining them into one using a power difference.

That is, the core layer data passes through the core layer BICM unit 310 , and the enhanced layer data passes through the enhanced layer BICM unit 320 , and then passes through the injection level controller 330 and is combined in the combiner 340 . In this case, the enhanced layer BICM unit 320 may perform BICM encoding different from that of the core layer BICM unit 310 . That is, the enhanced layer BICM unit 320 may perform error correction encoding or symbol mapping corresponding to a bit rate higher than that of the core layer BICM unit 310 . In addition, the enhanced layer BICM unit 320 may perform error correction encoding or symbol mapping that is less robust than the core layer BICM unit 310 .

For example, the core layer error correction encoder may have a lower bit rate than the enhanced layer error correction encoder. In this case, the enhanced layer symbol mapper may be less robust than the core layer symbol mapper.

The combiner 340 may be viewed as combining the core layer signal and the enhanced layer signal at different power levels. According to an embodiment, the power level adjustment may be performed on a core layer signal instead of an enhanced layer signal. In this case, the power of the core layer signal may be adjusted to be greater than the power of the enhanced layer signal.

Core layer data uses a low code rate FEC (forward error correction) code for robust reception, whereas enhanced layer data uses a high code rate FEC code for high data rate. can

That is, the core layer data may have a wider coverage in the same reception environment as compared to the enhanced layer data.

The enhanced layer data that has passed through the enhanced layer BICM unit 320 has its gain (or power) adjusted through the injection level controller 330 and is combined with the core layer data by the combiner 340 .

That is, the injection level controller 330 generates a power-reduced enhanced layer signal by reducing the power of the enhanced layer signal. In this case, the level of the signal controlled by the injection level controller 330 may be determined according to the injection level. In this case, the injection level in the case of inserting the signal B into the signal A may be defined as in Equation 1 below.

[Equation 1]

For example, assuming that the injection level is 3 dB when the enhanced layer signal is inserted into the core layer signal, the enhanced layer signal has a power level corresponding to half that of the core layer signal.

In this case, the injection level controller 330 may adjust the power level of the enhanced layer signal from 3.0 dB to 10.0 dB in 0.5 dB increments.

In general, the transmission power allocated to the core layer is allocated larger than the transmission power allocated to the enhanced layer, so that the receiver can preferentially decode the core layer.

In this case, the combiner 340 may be viewed as generating a multiplexed signal by combining the core layer signal and the power-reduced enhanced layer signal.

The signal combined by the combiner 340 is provided to the power normalizer 345 to lower the power by the power increase generated by the combination of the core layer signal and the enhanced layer signal to perform power control. That is, the power normalizer 345 lowers the power of the signal multiplexed by the combiner 340 to a power level corresponding to the core layer signal. Since the level of the combined signal is higher than the level of one layer signal, power normalization of the power normalizer 345 is required to prevent amplitude clipping in the rest of the broadcast signal transmission/reception system.

In this case, the power normalizer 345 may adjust the size of the appropriate signal by multiplying the normalizing factor of Equation 2 by the magnitude of the combined signal. Injection level information for calculating Equation 2 below may be transmitted to the power normalizer 345 through a signaling flow.

[Equation 2]

와 같이 표현될 수 있다.Assuming that the power levels of the core layer signal and the enhanced layer signal are normalized to 1 when the enhanced layer signal S _E is injected into the core layer signal S _C by a predetermined injection level, the combined signal is

can be expressed as

In this case, α represents a scaling factor corresponding to various injection levels. That is, the injection level controller 330 may correspond to the scaling factor.

와 같이 표현될 수 있다.For example, if the injection level of the enhanced layer is 3 dB, the combined signal is

can be expressed as

Since the power of the combined signal (the multiplexed signal) has increased compared to the core layer signal, the power normalizer 345 must mitigate this power increase.

와 같이 표현될 수 있다.The output of the power normalizer 345 is

can be expressed as

In this case, β represents a normalizing factor according to various injection levels of the enhanced layer.

와 같이 표현될 수 있다.When the injection level of the enhanced layer is 3 dB, the power increase of the combined signal compared to the core layer signal is 50%. Therefore, the output of the power normalizer 345 is

can be expressed as

Table 1 below shows the scaling factor α and the normalizing factor β according to various injection levels (CL: Core Layer, EL: Enhanced Layer). The relationship between the injection level and the scaling factor α and the normalizing factor β may be defined as follows.

[Equation 3]

EL Injection level relative to CL

Scaling factor

Normalizing factor

3.0 dB 0.7079458 0.8161736 3.5 dB 0.6683439 0.8314061 4.0 dB 0.6309573 0.8457262 4.5 dB 0.5956621 0.8591327 5.0 dB 0.5623413 0.8716346 5.5 dB 0.5308844 0.8832495 6.0 dB 0.5011872 0.8940022 6.5 dB 0.4731513 0.9039241 7.0 dB 0.4466836 0.9130512 7.5 dB 0.4216965 0.9214231 8.0 dB 0.3981072 0.9290819 8.5 dB 0.3758374 0.9360712 9.0 dB 0.3548134 0.9424353 9.5 dB 0.3349654 0.9482180 10.0 dB 0.3162278 0.9534626

That is, the power normalizer 345 corresponds to the normalizing factor, and it can be seen that the power of the multiplexed signal is lowered by the amount raised by the combiner 340 .

In this case, the normalizing factor and the scaling factor may be rational numbers greater than 0 and less than 1, respectively.

In this case, the scaling factor may decrease as the decrease in power corresponding to the injection level controller 330 increases, and the normalizing factor may increase as the decrease in power corresponding to the injection level controller 330 increases.

The power normalized signal passes through a time interleaver 350 for dispersing a burst error occurring in the channel.

In this case, the time interleaver 350 may be regarded as performing interleaving applied to the core layer signal and the enhanced layer signal together. That is, since the core layer and the enhanced layer share the time interleaver, unnecessary memory usage can be prevented and latency in the receiver can be reduced.

As will be described later, the enhanced layer signal may correspond to the enhanced layer data restored based on cancellation corresponding to the restoration of the core layer data corresponding to the core layer signal, and the combiner 340 is the core layer data. At least one extension layer signal having a lower power level than the signal and the enhanced layer signal may be combined with the core layer signal and the enhanced layer signal.

Meanwhile, the L1 signaling information including the injection level information is encoded by the L1 signaling generator 360 including the BICM dedicated to signaling. In this case, the L1 signaling generator 360 may receive the injection level information IL INFO from the injection level controller 330 to generate the L1 signaling signal.

In L1 signaling, L1 represents layer 1 (Layer-1), which is the lowest layer of the ISO 7 layer model. In this case, the L1 signaling may be included in the preamble.

In general, L1 signaling may include FFT size and guard interval size, which are main parameters of the OFDM transmitter, and channel code rate, which are main parameters of BICM, such as modulation information. The L1 signaling signal is combined with the data signal to form a broadcast signal frame.

The frame builder 370 generates a broadcast signal frame by combining the L1 signaling signal and the data signal.

A broadcast signal frame is transmitted through an OFDM transmitter that is robust to multi-path and Doppler. In this case, the OFDM transmitter can be considered to be in charge of generating a transmission signal of the next-generation broadcasting system.

4 is a diagram illustrating an example of a broadcast signal frame structure.

Referring to FIG. 4 , a broadcast signal frame includes an L1 signaling signal and a data signal. For example, the broadcast signal frame may be an ATSC 3.0 frame.

FIG. 5 is a block diagram illustrating another example of the signal multiplexing apparatus shown in FIG. 1 .

Referring to FIG. 5 , it can be seen that the signal multiplexing apparatus multiplexes data corresponding to N extension layers (N is a natural number greater than or equal to 1) in addition to the core layer data and the enhanced layer data.

That is, the signal multiplexing device shown in FIG. 5 includes a core layer BICM unit 310, an enhanced layer BICM unit 320, an injection level controller 330, a combiner 340, a power normalizer 345, and a time interleaver ( 350), the L1 signaling generator 360, and the frame builder 370, as well as N extension layer BICM units 410, ..., 430 and injection level controllers 440, ..., 460.

5, the core layer BICM unit 310, the enhanced layer BICM unit 320, the injection level controller 330, the combiner 340, the power normalizer 345, the time interleaver 350, and the L1 signaling generation The unit 360 and the frame builder 370 have already been described in detail with reference to FIG. 3 .

The N extension layer BICM units 410, ..., 430 independently perform BICM encoding, and the injection level controllers 440, ..., 460 perform power reducing corresponding to each extension layer. Thus, the power-reduced extension layer signal is combined with other layer signals through the combiner 340 .

In this case, the error correction encoder of each of the enhancement layer BICM units 410, ..., 430 may be a serial connection of a BCH encoder and an LDPC encoder.

In particular, it is preferable that the power reduction corresponding to each of the injection level controllers 440 , ..., 460 is greater than the power reduction of the injection level controller 330 . That is, the injection level controllers 330 , 440 , ..., 460 shown in FIG. 5 may correspond to a large power reduction as they go down.

The injection level information provided from the injection level controllers 330 , 440 , and 460 shown in FIG. 5 is included in the broadcast signal frame of the frame builder 370 through the L1 signaling generator 360 and transmitted to the receiver. That is, the injection level of each layer is contained in the L1 signaling information and delivered to the receiver.

In the present invention, power control may increase or decrease the power of the input signal, or may increase or decrease the gain of the input signal.

The power normalizer 345 mitigates a power increase caused by combining a plurality of layer signals by the combiner 340 .

In the example shown in FIG. 5 , the power normalizer 345 may adjust the signal power to an appropriate signal level by multiplying the normalizing factor by the size of the signal in which the signals of each layer are combined using Equation 4 below. .

[Equation 4]

Normalizing Factor =

The time interleaver 350 performs interleaving on the signals combined by the combiner 340 , thereby performing interleaving that is applied to the signals of the layers together.

6 is a block diagram illustrating an example of the signal demultiplexing apparatus shown in FIG. 1 .

Referring to FIG. 6 , the signal demultiplexing apparatus according to an embodiment of the present invention includes a time deinterleaver 510 , a de-normalizer 1010 , a core layer BICM decoder 520 , and an enhanced layer symbol extractor 530 . , a de-injection level controller 1020 and an enhanced layer BICM decoder 540 .

In this case, the signal demultiplexing device shown in FIG. 6 may correspond to the signal multiplexing device shown in FIG. 3 .

The time deinterleaver 510 receives a received signal from an OFDM receiver performing operations such as time/frequency synchronization, channel estimation, and equalization, and generates a burst error in the channel. Perform an operation related to dispersion. In this case, the L1 signaling information may be preferentially decoded in the OFDM receiver and utilized for data decoding. In particular, the injection level information among the L1 signaling information may be transmitted to the de-normalizer 1010 and the de-injection level controller 1020 . In this case, the OFDM receiver may decode the received signal in the form of a broadcast signal frame (eg, an ATSC 3.0 frame), extract a data symbol portion of the frame, and provide it to the time deinterleaver 510 . That is, the time deinterleaver 510 performs a deinterleaving process while passing data symbols to disperse clustering errors generated in the channel.

The de-normalizer 1010 corresponds to the power normalizer of the transmitter, and increases the power by the amount reduced by the power normalizer. That is, the de-normalizer 1010 divides the received signal by the normalizing factor of Equation (2).

In the example shown in FIG. 6 , the de-normalizer 1010 is illustrated as adjusting the power of the output signal of the time interleaver 510 , but according to an embodiment, the de-normalizer 1010 is the time interleaver 510 . It may be positioned in front of , so that power adjustment is performed before interleaving.

That is, the de-normalizer 1010 can be viewed as being positioned before or after the time interleaver 510 to amplify the signal size for the LLR calculation of the core layer symbol demapper.

The output of the time deinterleaver 510 (or the output of the de-normalizer 1010 ) is provided to the core layer BICM decoder 520 , and the core layer BICM decoder 520 restores core layer data.

In this case, the core layer BICM decoder 520 includes a core layer symbol demapper, a core layer bit deinterleaver, and a core layer error correction decoder. The core layer symbol demapper calculates the LLR (Log-Likelihood Ratio) values related to the symbol, the core layer bit deinterleaver strongly mixes the calculated LLR values with the cluster error, and the core layer error correction decoder detects the error occurring in the channel. correct it

In this case, the core layer symbol demapper may calculate the LLR value for each bit using a predetermined constellation. In this case, the constellation used in the core layer symbol mapper may be different according to a combination of a code rate and a modulation order used in the transmitter.

In this case, the core layer bit deinterleaver may perform deinterleaving on the calculated LLR values in units of LDPC codewords.

In particular, the core layer error correction decoder may output only information bits, or may output all bits in which information bits and parity bits are combined. In this case, the core layer error correction decoder may output only information bits as core layer data, and output all bits in which parity bits are combined with information bits to the enhanced layer symbol extractor 530 .

The core layer error correction decoder may be a type in which a core layer LDPC decoder and a core layer BCH decoder are serially connected. That is, the input of the core layer error correction decoder is input to the core layer LDPC decoder, the output of the core layer LDPC decoder is input to the core layer BCH decoder, and the output of the core layer BCH decoder is the output of the core layer error correction decoder. output can be In this case, the LDPC decoder performs LDPC decoding, and the BCH decoder performs BCH decoding.

Furthermore, the enhanced layer error correction decoder may also be a type in which the enhanced layer LDPC decoder and the enhanced layer BCH decoder are serially connected. That is, the input of the enhanced layer error correction decoder is input to the enhanced layer LDPC decoder, the output of the enhanced layer LDPC decoder is input to the enhanced layer BCH decoder, and the output of the enhanced layer BCH decoder is enhanced. It may be an output of a layer error correction decoder.

The enhanced layer symbol extractor 530 receives all bits from the core layer error correction decoder of the core layer BICM decoder 520 and receives the enhanced layer from the output signal of the time deinterleaver 510 or the de-normalizer 1010 . Symbols can be extracted. According to an embodiment, the enhanced layer symbol extractor 530 does not receive all bits from the error correction decoder of the core layer BICM decoder 520, and receives information bits of LDPC or BCH information bits. can be provided.

In this case, the enhanced layer symbol extractor 530 includes a buffer, a subtracter, a core layer symbol mapper, and a core layer bit interleaver. The buffer stores the output signal of the time deinterleaver 510 or the de-normalizer 1010 . The core layer bit interleaver receives all bits (information bits + parity bits) of the core layer BICM decoder and performs the same core layer bit interleaving as the transmitter. The core layer symbol mapper generates the same core layer symbols as the transmitter from the interleaved signal. The subtractor subtracts the output signal of the core layer symbol mapper from the signal stored in the buffer to obtain an enhanced layer symbol and transmits it to the de-injection level controller 1020 . In particular, when receiving the LDPC information bits, the enhanced layer symbol extractor 530 may further include a core layer LDPC encoder. In addition, when receiving BCH information bits, the enhanced layer symbol extractor 530 may further include a core layer BCH encoder as well as a core layer LDPC encoder.

At this time, the core layer LDPC encoder, the core layer BCH encoder, the core layer bit interleaver and the core layer symbol mapper included in the enhanced layer symbol extractor 530 are the LDPC encoder, BCH encoder, and bit interleaver of the core layer described with reference to FIG. 3 . and symbol mapper.

The de-injection level controller 1020 receives the enhanced layer symbol and increases the power by the power dropped by the injection level controller of the transmitter. That is, the de-injection level controller 1020 amplifies the input signal and provides it to the enhanced layer BICM decoder 540 . For example, if the transmitter combines the power of the enhanced layer signal to be 3 dB smaller than the power of the core layer signal, the de-injection level controller 1020 serves to increase the power of the input signal by 3 dB.

In this case, the de-injection level controller 1020 can be viewed as multiplying the enhanced layer signal extracted by receiving the injection level information from the OFDM receiver by the enhanced layer gain of Equation 5 below.

[Equation 5]

Enhanced Layer Gain =

The enhanced layer BICM decoder 540 receives the enhanced layer symbol whose power is increased by the de-injection level controller 1020 and restores the enhanced layer data.

In this case, the enhanced layer BICM decoder 540 may include an enhanced layer symbol demapper, an enhanced layer bit deinterleaver, and an enhanced layer error correction decoder. The enhanced layer symbol demapper calculates LLR (Log-Likelihood Ratio) values related to the enhanced layer symbol, and the enhanced layer bit deinterleaver strongly mixes the calculated LLR values with the cluster error, and decodes the enhanced layer error correction. The device corrects errors that occur in the channel.

The enhanced layer BICM decoder 540 performs a similar operation to the core layer BICM decoder 520 , but in general, the enhanced layer LDPC decoder performs LDPC decoding for a code rate of 6/15 or higher.

For example, the core layer may use an LDPC code having a code rate of 5/15 or less, and the enhanced layer may use an LDPC code having a code rate of 6/15 or more. In this case, in a reception environment in which the enhanced layer data can be decoded, the core layer data can be decoded using only a small number of LDPC decoding iterations. Using this property, the receiver hardware shares one LDPC decoder between the core layer and the enhanced layer, thereby reducing the cost incurred in hardware implementation. In this case, the core layer LDPC decoder may use only some time resources (LDPC decoding iteration) and the enhanced layer LDPC decoder may use most of the time resources.

The signal demultiplexing apparatus shown in FIG. 6 first restores the core layer data, cancels the core layer symbols from the received signal symbols to leave only the enhanced layer symbols, and then increases the power of the enhanced layer symbols to enhance the enhancement. Restore the de-layer data. As already described with reference to FIGS. 3 and 5 , since signals corresponding to each layer are combined at different power levels, data restoration with the least error is possible only when the signal combined with the strongest power is restored.

As a result, in the example shown in FIG. 6 , the signal demultiplexing apparatus includes: a time deinterleaver 510 for generating a time deinterleaving signal by applying time deinterleaving to a received signal; a de-normalizer (1010) that increases the power of the received signal or the time deinterleaving signal by a power reduction by a power normalizer of a transmitter; a core layer BICM decoder (520) for reconstructing core layer data from a signal whose power is adjusted by the de-normalizer (1010); By using the output signal of the core layer FEC decoder of the core layer BICM decoder 520 , cancellation corresponding to the core layer data is performed on the signal whose power is adjusted by the de-normalizer 1010 to perform enhanced enhancement. an enhanced layer symbol extractor 530 for extracting a layer signal; a de-injection level controller 1020 that increases the power of the enhanced layer signal by a power decrease of the injection level controller of the transmitter; and an enhanced layer BICM decoder 540 that reconstructs enhanced layer data using an output signal of the de-injection level controller 1020 .

In this case, the enhanced layer symbol extractor may receive the entire codeword from the core layer LDPC decoder of the core layer BICM decoder, and may directly bit interleave the entire codeword.

In this case, the enhanced layer symbol extractor may receive information bits from the core layer LDPC decoder of the core layer BICM decoder, perform core layer LDPC encoding on the information bits, and then perform bit interleaving.

In this case, the enhanced layer symbol extractor may receive information bits from the core layer BCH decoder of the core layer BICM decoder, perform core layer BCH encoding and core layer LDPC encoding on the information bits, and then perform bit interleaving.

In this case, the de-normalizer and the de-injection level controller may receive the provided injection level information (IL INFO) based on L1 signaling, and perform power control based on the injection level information.

In this case, the core layer BICM decoder may have a lower bit rate than the enhanced layer BICM decoder and may be more robust than the enhanced layer BICM decoder.

In this case, the de-normalizer may correspond to the reciprocal of the normalizing factor.

In this case, the de-injection level controller may correspond to the reciprocal of the scaling factor.

In this case, the enhanced layer data may be restored based on cancellation corresponding to the restoration of the core layer data corresponding to the core layer signal.

In this case, the signal demultiplexing apparatus includes: one or more enhancement layer symbol extractors for extracting enhancement layer signals by performing cancellation corresponding to previous layer data; One or more de-injection level controllers that increase the power of the extension layer signal by the power reduction of the injection level controller of the transmitter, and one or more extensions to restore one or more extension layer data using an output signal of the one or more de-injection level controllers It may further include a layer BICM decoder.

A signal demultiplexing method according to an embodiment of the present invention through the configuration shown in FIG. 6 includes generating a time deinterleaving signal by applying time deinterleaving to a received signal; increasing the power of the received signal or the time deinterleaving signal by a power reduction by a power normalizer of a transmitter; restoring core layer data from the power-adjusted signal; extracting an enhanced layer signal by performing cancellation corresponding to the core layer data on the power-adjusted signal; increasing the power of the enhanced layer signal by a power decrease of an injection level controller of the transmitter; and restoring enhanced layer data by using the power-adjusted enhanced layer signal.

In this case, in extracting the enhanced layer signal, the entire codeword may be received from the core layer LDPC decoder of the core layer BICM decoder, and the entire codeword may be bit interleaved.

In this case, the step of extracting the enhanced layer signal may include receiving information bits from the core layer LDPC decoder of the core layer BICM decoder, performing core layer LDPC encoding on the information bits, and then performing bit interleaving.

In this case, the step of extracting the enhanced layer signal may include receiving information bits from the core layer BCH decoder of the core layer BICM decoder, performing core layer BCH encoding and core layer LDPC encoding on the information bits, and then performing bit interleaving. .

FIG. 7 is a block diagram illustrating an example of the core layer BICM decoder 520 and the enhanced layer symbol extractor 530 shown in FIG. 6 .

Referring to FIG. 7 , the core layer BICM decoder 520 includes a core layer symbol demapper, a core layer bit deinterleaver, a core layer LDPC decoder, and a core layer BCH decoder.

That is, in the example shown in FIG. 7 , the core layer error correction decoder includes a core layer LDPC decoder and a core layer BCH decoder.

In addition, in the example shown in FIG. 7 , the core layer LDPC decoder provides a whole codeword including parity bits to the enhanced layer symbol extractor 530 . That is, in general, the LDPC decoder outputs only information bits among all the LDPC codewords, but it is also possible to output the entire codeword.

In this case, the enhanced layer symbol extractor 530 is simple to implement because it does not need to separately include a core layer LDPC encoder or a core layer BCH encoder, but there is a possibility that a residual error remains in the LDPC code parity part.

8 is a block diagram illustrating another example of the core layer BICM decoder 520 and the enhanced layer symbol extractor 530 illustrated in FIG. 6 .

Referring to FIG. 8 , the core layer BICM decoder 520 includes a core layer symbol demapper, a core layer bit deinterleaver, a core layer LDPC decoder, and a core layer BCH decoder.

That is, in the example shown in FIG. 8 , the core layer error correction decoder includes a core layer LDPC decoder and a core layer BCH decoder.

In addition, in the example shown in FIG. 8 , the core layer LDPC decoder provides information bits that do not include parity bits to the enhanced layer symbol extractor 530 .

In this case, the enhanced layer symbol extractor 530 does not need to separately include a core layer BCH encoder, but must include a core layer LDPC encoder.

Compared to the example shown in FIG. 7 , the example shown in FIG. 8 may remove residual errors that may remain in the parity part of the LDPC code.

9 is a block diagram illustrating another example of the core layer BICM decoder 520 and the enhanced layer symbol extractor 530 shown in FIG. 6 .

Referring to FIG. 9 , the core layer BICM decoder 520 includes a core layer symbol demapper, a core layer bit deinterleaver, a core layer LDPC decoder, and a core layer BCH decoder.

That is, in the example shown in FIG. 9 , the core layer error correction decoder includes a core layer LDPC decoder and a core layer BCH decoder.

In the example shown in FIG. 9 , the output of the core layer BCH decoder corresponding to the core layer data is provided to the enhanced layer symbol extractor 530 .

In this case, the enhanced layer symbol extractor 530 has high complexity because it must include both the core layer LDPC encoder and the core layer BCH encoder, but guarantees the highest performance compared to the examples of FIGS. 7 and 8 .

FIG. 10 is a block diagram illustrating another example of the signal demultiplexing apparatus shown in FIG. 1 .

Referring to FIG. 10 , the signal demultiplexing apparatus according to an embodiment of the present invention includes a time deinterleaver 510 , a de-normalizer 1010 , a core layer BICM decoder 520 , and an enhanced layer symbol extractor 530 . , the enhanced layer BICM decoder 540, one or more enhancement layer symbol extractors 650, 670, one or more enhancement layer BICM decoders 660, 680 and de-injection level controllers 1020, 1150, 1170. include

In this case, the signal demultiplexing device shown in FIG. 10 may correspond to the signal multiplexing device shown in FIG. 5 .

The time deinterleaver 510 receives a received signal from an OFDM receiver performing operations such as synchronization, channel estimation, and equalization, and relates to the distribution of burst error generated in the channel. perform the action In this case, the L1 signaling information may be preferentially decoded in the OFDM receiver and utilized for data decoding. In particular, the injection level information among the L1 signaling information may be transmitted to the de-normalizer 1010 and the de-injection level controllers 1020 , 1150 , and 1170 .

In this case, the de-normalizer 1010 may obtain the injection level information of all layers, obtain a de-normalizing factor using Equation 6 below, and multiply the input signal.

[Equation 6]

De-Normalizing factor = (Normalizing factor) ^-1 =

That is, the de-normalizing factor is the reciprocal of the normalizing factor expressed by Equation (4).

According to an embodiment, when the N1 signaling includes not only the injection level information but also the normalizing factor information, the de-normalizer 1010 simply de-normalizes by taking the reciprocal of the normalizing factor without having to calculate the de-normalizing factor using the injection level. The normalizing factor can be obtained.

The de-normalizer 1010 corresponds to the power normalizer of the transmitter, and increases the power by the amount reduced by the power normalizer.

In the example shown in FIG. 10 , the de-normalizer 1010 is illustrated as adjusting the power of the output signal of the time interleaver 510 , but according to an embodiment, the de-normalizer 1010 is the time interleaver 510 . It may be positioned in front of , so that power adjustment is performed before interleaving.

That is, the de-normalizer 1010 can be viewed as being positioned before or after the time interleaver 510 to amplify the signal size for the LLR calculation of the core layer symbol demapper.

The output of the time deinterleaver 510 (or the output of the de-normalizer 1010 ) is provided to the core layer BICM decoder 520 , and the core layer BICM decoder 520 restores core layer data.

In this case, the core layer BICM decoder 520 includes a core layer symbol demapper, a core layer bit deinterleaver, and a core layer error correction decoder. The core layer symbol demapper calculates the LLR (Log-Likelihood Ratio) values related to the symbol, the core layer bit deinterleaver strongly mixes the calculated LLR values with the cluster error, and the core layer error correction decoder detects the error occurring in the channel. correct it

In particular, the core layer error correction decoder may output only information bits, or may output all bits in which information bits and parity bits are combined. In this case, the core layer error correction decoder may output only information bits as core layer data, and output all bits in which parity bits are combined with information bits to the enhanced layer symbol extractor 530 .

The core layer error correction decoder may be a type in which a core layer LDPC decoder and a core layer BCH decoder are serially connected. That is, the input of the core layer error correction decoder is input to the core layer LDPC decoder, the output of the core layer LDPC decoder is input to the core layer BCH decoder, and the output of the core layer BCH decoder is the output of the core layer error correction decoder. output can be In this case, the LDPC decoder performs LDPC decoding, and the BCH decoder performs BCH decoding.

The enhanced layer error correction decoder may also have a serial connection type between the enhanced layer LDPC decoder and the enhanced layer BCH decoder. That is, the input of the enhanced layer error correction decoder is input to the enhanced layer LDPC decoder, the output of the enhanced layer LDPC decoder is input to the enhanced layer BCH decoder, and the output of the enhanced layer BCH decoder is enhanced. It may be an output of a layer error correction decoder.

Furthermore, the enhancement layer error correction decoder may also be a type in which the enhancement layer LDPC decoder and the enhancement layer BCH decoder are serially connected. That is, the input of the enhancement layer error correction decoder is input to the enhancement layer LDPC decoder, the output of the enhancement layer LDPC decoder is input to the enhancement layer BCH decoder, and the output of the enhancement layer BCH decoder is the output of the enhancement layer error correction decoder. output can be

In particular, the trade-off between implementation complexity and performance depending on which one of the outputs of the error correction decoder described with reference to FIGS. 7, 8 and 9 is used is the core layer BICM decoder 520 of FIG. It is applied not only to the enhanced layer symbol extractor 530 , but also to the enhancement layer symbol extractors 650 and 670 , and the enhancement layer BICM decoders 660 and 680 .

The enhanced layer symbol extractor 530 receives all bits from the core layer error correction decoder of the core layer BICM decoder 520 and receives the enhanced layer from the output signal of the time deinterleaver 510 or the de-normalizer 1010 . Symbols can be extracted. According to an embodiment, the enhanced layer symbol extractor 530 does not receive all bits from the error correction decoder of the core layer BICM decoder 520, and receives information bits of LDPC or BCH information bits. can be provided.

In this case, the enhanced layer symbol extractor 530 includes a buffer, a subtracter, a core layer symbol mapper, and a core layer bit interleaver. The buffer stores the output signal of the time deinterleaver 510 or the de-normalizer 1010 . The core layer bit interleaver receives all bits (information bits + parity bits) of the core layer BICM decoder and performs the same core layer bit interleaving as the transmitter. The core layer symbol mapper generates the same core layer symbols as the transmitter from the interleaved signal. The subtractor subtracts the output signal of the core layer symbol mapper from the signal stored in the buffer to obtain an enhanced layer symbol and transmits it to the de-injection level controller 1020 .

In this case, the core layer bit interleaver and the core layer symbol mapper included in the enhanced layer symbol extractor 530 may be the same as the core layer bit interleaver and the symbol mapper illustrated in FIG. 5 .

The de-injection level controller 1020 receives the enhanced layer symbol and increases the power by the power dropped by the injection level controller of the transmitter. That is, the de-injection level controller 1020 amplifies the input signal and provides it to the enhanced layer BICM decoder 540 .

The enhanced layer BICM decoder 540 receives the enhanced layer symbol whose power is increased by the de-injection level controller 1020 and restores the enhanced layer data.

In this case, the enhanced layer BICM decoder 540 may include an enhanced layer symbol demapper, an enhanced layer bit deinterleaver, and an enhanced layer error correction decoder. The enhanced layer symbol demapper calculates LLR (Log-Likelihood Ratio) values related to the enhanced layer symbol, and the enhanced layer bit deinterleaver strongly mixes the calculated LLR values with the cluster error, and decodes the enhanced layer error correction. The device corrects errors that occur in the channel.

In particular, the enhanced layer error correction decoder may output only information bits, or may output all bits in which information bits and parity bits are combined. In this case, the enhanced layer error correction decoder may output only information bits as enhanced layer data, and output all bits in which parity bits are combined with information bits to the enhancement layer symbol extractor 650 .

The extension layer symbol extractor 650 receives all bits from the enhanced layer error correction decoder of the enhanced layer BICM decoder 540 and extracts extension layer symbols from the output signal of the de-injection level controller 1020 do.

In this case, the de-injection level controller 1020 may amplify the power of the output signal of the subtractor of the enhanced layer symbol extractor 530 .

In this case, the enhancement layer symbol extractor 650 includes a buffer, a subtracter, an enhanced layer symbol mapper, and an enhanced layer bit interleaver. The buffer stores the output signal of the de-injection level controller 1020 . The enhanced layer bit interleaver receives all bits (information bits + parity bits) of the enhanced layer BICM decoder and performs the same enhanced layer bit interleaving as the transmitter. The enhanced layer symbol mapper generates the same enhanced layer symbols as the transmitter from the interleaved signal. The subtractor subtracts the output signal of the enhanced layer symbol mapper from the signal stored in the buffer to obtain an enhancement layer symbol and transmits it to the de-injection level controller 1150 .

In this case, the enhanced layer bit interleaver and enhanced layer symbol mapper included in the enhancement layer symbol extractor 650 may be the same as the enhanced layer bit interleaver and symbol mapper illustrated in FIG. 5 .

The de-injection level controller 1150 increases the power by the amount reduced by the injection level controller of the corresponding layer in the transmitter.

At this time, it can be seen that the de-injection level controller performs an operation of multiplying the extension layer gain of Equation 7 below. In this case, the 0th injection level may be regarded as 0dB.

[Equation 7]

n-th Extension Layer Gain =

The extension layer BICM decoder 660 receives the extension layer symbol whose power is increased by the de-injection level controller 1150 and restores the extension layer data.

In this case, the enhancement layer BICM decoder 660 may include an enhancement layer symbol demapper, an enhancement layer bit deinterleaver, and an enhancement layer error correction decoder. The extension layer symbol demapper calculates LLR (Log-Likelihood Ratio) values related to the extension layer symbol, the extension layer bit deinterleaver strongly mixes the calculated LLR values with the cluster error, and the extension layer error correction decoder calculates the LLR values generated in the channel. Correct the error.

In particular, when there are two or more enhancement layers, two or more enhancement layer symbol extractors and enhancement layer BICM decoders may be provided respectively.

That is, in the example shown in FIG. 10 , the enhancement layer error correction decoder of the enhancement layer BICM decoder 660 may output only information bits, and output all bits in which information bits and parity bits are combined. may be In this case, the enhancement layer error correction decoder may output only information bits as enhancement layer data, and output all bits in which parity bits are combined with information bits to the next enhancement layer symbol extractor 670 .

The structure and operation of the enhancement layer symbol extractor 670, the enhancement layer BICM decoder 680, and the de-injection level controller 1170 are the aforementioned enhancement layer symbol extractor 650, enhancement layer BICM decoder 660 and de-injection. It can be easily seen from the structure and operation of the level controller 1150 .

The de-injection level controllers 1020 , 1150 , and 1170 illustrated in FIG. 10 may correspond to a larger power increase as they go down. That is, the de-injection level controller 1150 increases the power more than the de-injection level controller 1020 , and the de-injection level controller 1170 increases the power more significantly than the de-injection level controller 1150 . can do it

The signal demultiplexing apparatus shown in FIG. 10 first restores the core layer data, restores the enhanced layer data by using the cancellation of the core layer symbol, and restores the extension layer data by using the cancellation of the enhanced layer symbol. can be found to restore. Two or more extension layers may be provided, and in this case, the extension layer combined with a higher power level is restored.

11 is a diagram illustrating a power increase due to a combination of a core layer signal and an enhanced layer signal.

Referring to FIG. 11 , when the multiplexed signal is generated by combining the core layer signal with the enhanced layer signal with reduced power by the injection level, the power level of the multiplexed signal is the core layer signal or the enhanced layer signal. It can be seen that it is higher than the power level.

At this time, the injection level controlled by the injection level controller shown in FIGS. 3 and 5 may be adjusted from 3.0 dB to 10.0 dB at 0.5 dB intervals. When the injection level is 3.0dB, the power of the enhanced layer signal is 3dB lower than the power of the core layer signal. When the injection level is 10.0 dB, the power of the enhanced layer signal is 10 dB lower than the power of the core layer signal. Such a relationship may be applied not only between the core layer signal and the enhanced layer signal, but also between the enhanced layer signal and the enhancement layer signal or enhancement layer signals.

The power normalizer shown in FIGS. 3 and 5 can solve problems such as distortion of a signal that may be caused by an increase in power due to combining by adjusting the power level after combining.

12 is a flowchart illustrating a signal multiplexing method according to an embodiment of the present invention.

12, in the signal multiplexing method according to an embodiment of the present invention, BICM is applied to core layer data (S1210).

Also, in the signal multiplexing method according to an embodiment of the present invention, BICM is applied to enhanced layer data (S1220).

The BICM applied in step S1220 and the BICM applied in step S1210 may be different. In this case, the BICM applied in step S1220 may be less robust than the BICM applied in step S1210 . In this case, the bit rate of the BICM applied in step S1220 may be greater than the bit rate applied in step S1210.

In this case, the enhanced layer signal may correspond to the enhanced layer data restored based on cancellation corresponding to the restoration of the core layer data corresponding to the core layer signal.

In addition, the signal multiplexing method according to an embodiment of the present invention generates a power-reduced enhanced layer signal by reducing the power of the enhanced layer signal (S1230).

In this case, step S1230 may change the injection level from 3.0 dB to 10.0 dB at 0.5 dB intervals.

In addition, the signal multiplexing method according to an embodiment of the present invention generates a multiplexed signal by combining the core layer signal and the power-reduced enhanced layer signal (S1240).

That is, in step S1240, the core layer signal and the enhanced layer signal are combined at different power levels, but the power level of the enhanced layer signal is lower than the power level of the core layer signal.

In this case, in step S1240, the core layer signal and one or more extension layer signals having a lower power level than the enhanced layer signal may be combined with the core layer signal and the enhanced layer signal.

In addition, the signal multiplexing method according to an embodiment of the present invention lowers the power of the signal multiplexed by the step (S1250) (S1250).

In this case, in step S1250, the power of the multiplexed signal may be lowered by the power of the core layer signal. In this case, in step S1250, the power of the multiplexed signal may be lowered by the amount increased by the step S1240.

In addition, the signal multiplexing method according to an embodiment of the present invention generates a time interleaved signal by performing time interleaving applied to the core layer signal and the enhanced layer signal together (S1260).

Also, in the signal multiplexing method according to an embodiment of the present invention, a broadcast signal frame is generated by using the time-interleaved signal and L1 signaling information (S1270).

In this case, the broadcast signal frame may be an ATSC 3.0 frame.

In this case, the L1 signaling information may include injection level information and/or normalizing factor information.

Although not explicitly shown in FIG. 12 , the signal multiplexing method may further include generating L1 signaling information including injection level information corresponding to step S1230 .

The signal multiplexing method shown in FIG. 12 may correspond to step S210 shown in FIG. 2 .

The layered division multiplexing (LDM) described above can be applied to a next-generation broadcasting system such as ATSC3.0 because each service can use 100% of time and frequency resources while simultaneously supporting multiple services.

In particular, when the layered division multiplexing technology is combined with a scalable video codec technology such as SVC or SHVC, a more flexible and efficient broadcast service can be provided to users.

In the case of using a scalable video codec such as SVC or SHVC in video coding, if a broadcasting system to which Layered Division Multiplexing is applied is used as the physical layer of the broadcasting system, the original purpose and advantages of the scalable video codec are can be saved

13 is a block diagram illustrating a scalable video content broadcasting apparatus according to an embodiment of the present invention.

Referring to FIG. 13 , the scalable video content broadcasting apparatus according to an embodiment of the present invention includes a video codec unit 1310 , an encapsulation and delivery unit 1320 , and a broadcast signal multiplexing unit 1330 .

The video codec unit 1310 generates a plurality of codec layer signals by dividing the codec media stream into a plurality of layers.

In the example shown in FIG. 13 , SHVC is used as a video codec, and media content to be serviced is generated by dividing it into two layers: a base layer and an enhancement layer.

In this case, the base layer includes image information corresponding to high definition (HD) quality, and combining the base layer and the enhancement layer may provide an image of ultra high definition (HD) quality.

The base layer signal and the enhancement layer signal generated from the video codec unit 1310 are input to the encapsulation and delivery unit 1320 .

The encapsulation and delivery unit 1320 converts codec layer signals for transmission.

That is, the encapsulation and delivery unit 1320 serves to convert pure media content data into a form that can be transmitted.

At this time, when the input data is composed of a plurality of layers, the encapsulation and delivery unit 1320 provides the relationship information between the layers, time stamp information for synchronization between layers, etc. together with the media content data as a physical layer. It can be provided to the broadcast signal multiplexer.

For example, the encapsulation and delivery unit 1320 may be implemented using a Dynamic Adaptive Streaming over HTTP (DASH) technology for an ATSC 3.0 broadcast system or an MPEG Media Transport (MMT) technology.

The broadcast signal multiplexer 1330 combines a plurality of codec layer signals at different power levels to generate a layered division multiplexed broadcast signal.

In this case, the broadcast signal multiplexer 1330 may combine the codec layer signals converted by the encapsulation and delivery unit 1320 rather than directly combining the codec layer signals.

In this case, the codec layer signals may correspond to the layers of the broadcast signal multiplexer 1330 in a 1:1 ratio.

At this time, the codec layer signals include a base layer signal and an enhanced layer signal, the base layer signal corresponds to the core layer signal of the broadcast signal multiplexing unit 1330, and the enhancement layer signal is the broadcast signal multiplexing unit ( 1330) may correspond to the enhanced layer signal.

In this case, the broadcast signal multiplexer 1330 may correspond to the ATSC 3.0 physical layer.

In this case, the broadcast signal multiplexing unit 1330 may correspond to the signal multiplexing apparatus shown in FIG. 3 .

The base layer signal converted by the encapsulation and delivery unit 1320 is input to the core layer BICM as core layer data, and the enhancement layer signal converted by the encapsulation and delivery unit 1320 is enhanced layer data. As such, it can be input to the enhanced layer BICM.

The base layer signal and the core layer signal passing through different BICMs may be combined at different power levels, and passed through a power normalizer and a time interleaver to be delivered to a frame builder.

14 is a diagram illustrating an example of codec layer signals.

Referring to FIG. 14 , it is possible to provide an image corresponding to HD quality by using only a base layer signal among codec layer signals.

In addition, when the base layer signal and the enhancement layer signal among the codec layer signals are used together, it is possible to provide an image corresponding to an ultra HD level quality.

FIG. 15 is a diagram illustrating a transmission signal spectrum of the scalable video content broadcasting apparatus shown in FIG. 13 .

Referring to FIG. 15 , it can be seen that the signal output from the scalable video content broadcasting apparatus of FIG. 13 is overlapped and transmitted in the form of a spectrum overlay.

In the case of a layered division multiplexing-based receiver, a core layer, which is the highest layer, is first decoded, and a lower layer is sequentially decoded. This is very similar to preferentially decoding the base layer and sequentially decoding the enhancement layer in SVC or SHVC.

Even if the video codec provides a high level of scalability, the transmission physical layer fails to provide adequate scalability, and as a result, the receiver often fails to provide sufficient scalability. have.

That is, when a layered division multiplexing-based transmission system is used, since sequential decoding is performed in the physical layer, a sequential decoding environment that is a desired environment for SVC or SHVC is provided, and scalability of media content is guaranteed.

For example, as in the example of FIG. 14 , in the case of a mobile device or tablet device with a small screen and limited receiver performance, only the core layer is decoded and media content corresponding to the base layer of SHVC is obtained to obtain HD quality quality. An image may be provided to the user. In addition, when a large screen and excellent performance such as a TV are provided, the core layer is decoded first and then the enhanced layer is decoded to obtain media content corresponding to the SHVC base layer and the SHVC enhancement layer, thereby providing UHD quality quality. An image may be provided to the user.

16 is a block diagram illustrating a scalable video content broadcasting apparatus according to another embodiment of the present invention.

Referring to FIG. 16 , the scalable video content broadcasting apparatus includes a video codec unit 1310 , an encapsulation and delivery unit 1320 , and a broadcast signal multiplexing unit 1330 .

The example shown in FIG. 16 shows an LDM-based broadcast transmitter for an SHVC media stream broadcast service having three layers.

17 is a diagram illustrating another example of codec layer signals.

Referring to FIG. 17 , a receiver capable of receiving only the SHVC base layer may provide a broadcast service with an image quality that opposes the lowest image quality.

In a general home TV, in order to enjoy a higher quality image, the base layer and the enhancement layer #1 may be combined and decoded.

In super-large TVs, not only the base layer and the enhancement layer #1 but also the enhancement layer #2 are combined to provide an ultra-high-definition image, so that the highest quality image can be provided.

The broadcast signal multiplexing unit 1330 shown in FIG. 16 may correspond to the signal multiplexing device shown in FIG. 5 (when there is one extension layer). The lowest quality SHVC base layer data is demodulated through the core layer BICM, the SHVC enhancement layer #1 data is demodulated in the enhanced layer BICM, and the SHVC enhancement layer #2 data can be demodulated in the extension layer BICM. The demodulated signals in each BICM may be combined with different power levels and passed through a time interleaver to be delivered to a frame builder.

18 is a diagram illustrating a transmission signal spectrum of the scalable video content broadcasting apparatus shown in FIG. 16 .

Referring to FIG. 18 , it can be seen that the signal output from the scalable video content broadcasting apparatus of FIG. 16 is overlapped and transmitted in the form of a triple spectrum overlay.

According to an embodiment, when transmitting an SHVC media stream having three layers, two SHVC layers may be mapped to one physical layer and transmitted.

That is, when the number of layers of the LDM broadcasting system is fixed to two in order to reduce receiver complexity, two or more SHVC enhancement layers may be combined through a mux to generate one media stream.

For example, as shown in FIG. 16 , when SHVC base layer data, SHVC enhancement layer #1 data, and SHVC enhancement layer #2 data are provided to the broadcast signal multiplexer, the SHVC base layer data is transmitted through the core layer BICM. After being demodulated, the SHVC enhancement layer #1 data and the SHVC enhancement layer #2 data may be combined through a multiplexer and then demodulated through one enhanced layer BICM.

19 is a diagram illustrating a transmission signal spectrum when two enhancement layer signals are mapped to one enhanced layer.

Referring to FIG. 19 , it can be seen that two layers are transmitted overlaid in the form of a spectrum overlay. In this case, the enhanced layer of the physical layer serves to transmit information corresponding to the SHVC enhancement layer #1 and the SHVC enhancement layer #2.

In this way, when video codec layers are combined and allocated to one LDM layer, even when there are three or more video codec layers, the entire media stream can be serviced using only two BICM blocks.

20 is a flowchart illustrating a method for broadcasting scalable video content according to an embodiment of the present invention.

Referring to FIG. 20 , in the method for broadcasting scalable video content according to an embodiment of the present invention, a plurality of codec layer signals are generated ( S2010 ).

In this case, the plurality of codec layer signals may be generated by dividing the codec media stream into a plurality of layers.

Also, in the method for broadcasting scalable video content according to an embodiment of the present invention, the codec layer signals are converted for transmission (S2020).

In addition, in the method for broadcasting scalable video content according to an embodiment of the present invention, a layered division multiplexed broadcasting signal is generated by combining the plurality of codec layer signals at different power levels ( S2030 ).

In this case, the codec layer signals may correspond to the layers of the layered division multiplexing 1:1.

In this case, the codec layer signals include a base layer signal and an enhancement layer signal, the base layer signal corresponds to the core layer signal of the layered division multiplexing, and the enhancement layer signal is the enhanced layer of the layered division multiplexing It may correspond to a signal.

In this case, the generating of the broadcast signal may include: generating a multiplexed signal by combining the core layer signal and the enhanced layer signal at different power levels; lowering the power of the multiplexed signal to a power corresponding to the core layer signal; generating a time interleaved signal by performing interleaving applied to the core layer signal and the enhanced layer signal together; and generating a broadcast signal frame corresponding to the layered division multiplexed broadcast signal by using the time interleaved signal and the L1 signaling information.

At this time, the generating of the multiplexed signal may include combining the core layer signal and one or more extension layer signals of a lower power level than the enhanced layer signal with the core layer signal and the enhanced layer signal. can

In this case, the codec layer signals may further include an additional enhancement layer signal, and the additional enhancement layer signal may correspond to the extension layer signal.

In this case, the codec layer signals include a base layer signal and two or more enhancement layer signals, the base layer signal corresponds to the core layer signal of the layered division multiplexing, and the enhancement layer signals are the enhancement layer signals of the layered division multiplexing. It may correspond to a de-layer signal.

As described above, in the scalable video content broadcasting apparatus and method according to the present invention, the configuration and method of the above-described embodiments are not limitedly applicable. All or part of the examples may be selectively combined and configured.

310: core layer BICM unit
320: enhanced layer BICM unit
330: injection level controller
340: combiner
350: time interleaver
345: power normalizer
1310: video codec unit
1320: Encapsulation and delivery unit
1330: broadcast signal multiplexing unit

Claims (20)

a video codec unit dividing the codec media stream into a plurality of layers to generate a plurality of codec layer signals;
an encapsulation and delivery unit that converts the codec layer signals for transmission; and
and a broadcast signal multiplexer for generating a layered division multiplexed broadcast signal by combining the multiplexer layer signals corresponding to the plurality of codec layer signals at different power levels;
The codec layer signals include a base layer signal and an enhancement layer signal, the base layer signal corresponds to a core layer signal of the broadcast signal multiplexing unit, and the enhancement layer signal is an enhanced layer signal of the broadcast signal multiplexing unit. corresponded,
The broadcast signal multiplexing unit
an injection level controller for generating a power-reduced enhanced layer signal by reducing the power of the enhanced layer signal;
a combiner for generating a multiplexed signal by combining the core layer signal and the power reduced enhanced layer signal by layered division multiplexing (LDM); and
and a power normalizer for lowering the power of the multiplexed signal to a power corresponding to the core layer signal,
The injection level controller reduces the power of the enhanced layer signal in accordance with a scaling factor,
The power normalizer reduces the power of the multiplexed signal according to a normalizing factor,
The scalable video content broadcasting apparatus according to claim 1, wherein the scaling factor and the normalizing factor change in opposite directions according to a change in power reduction corresponding to the injection level controller. The method according to claim 1,
The scalable video content broadcasting apparatus according to claim 1, wherein the codec layer signals correspond to the layers of the broadcast signal multiplexer in a 1:1 ratio. delete The method according to claim 1,
The broadcast signal multiplexing unit
a time interleaver configured to generate a time interleaved signal by performing interleaving applied to the core layer signal and the enhanced layer signal together; and
and a frame builder generating a broadcast signal frame corresponding to the layered division multiplexed broadcast signal by using the time interleaved signal and the L1 signaling information. delete 5. The method according to claim 4,
The broadcast signal multiplexing unit
a core layer BICM unit corresponding to the core layer signal; and
The scalable video content broadcasting apparatus according to claim 1, further comprising an enhanced layer BICM unit that performs BICM encoding different from the core layer BICM unit. The method according to claim 1,
The power normalizer is
The scalable video content broadcasting apparatus according to claim 1, wherein the power of the multiplexed signal is lowered by the amount increased by the combiner. 8. The method of claim 7,
The normalizing factor is a value greater than 0 and less than 1,
The scaling factor decreases as the power reduction corresponding to the injection level controller increases,
The scalable video content broadcasting apparatus according to claim 1, wherein the normalizing factor increases as the power reduction corresponding to the injection level controller increases. 9. The method of claim 8,
The enhanced layer signal is
The scalable video content broadcasting apparatus according to claim 1, wherein the scalable video content broadcasting apparatus corresponds to the enhanced layer data restored based on cancellation corresponding to the restoration of the core layer data corresponding to the core layer signal. 10. The method of claim 9,
the coupler
The scalable video content broadcasting apparatus according to claim 1, wherein the core layer signal and one or more extension layer signals having a lower power level than the enhanced layer signal are combined with the core layer signal and the enhanced layer signal. 11. The method of claim 10,
The codec layer signals further include an additional enhancement layer signal,
The scalable video content broadcasting apparatus, wherein the additional enhancement layer signal corresponds to the extension layer signal. The method according to claim 1,
The codec layer signals include a base layer signal and two or more enhancement layer signals, the base layer signal corresponds to a core layer signal of the broadcast signal multiplexing unit, and the enhancement layer signals are an enhanced layer signal of the broadcast signal multiplexing unit. A scalable video content broadcasting apparatus corresponding to a signal. 13. The method of claim 12,
The enhancement layer signals are
The scalable video content broadcasting apparatus according to claim 1, wherein multiplexing is performed using a multiplexer provided in the broadcast signal multiplexer to correspond to the enhanced layer signal. generating a plurality of codec layer signals by dividing the codec media stream into a plurality of layers;
performing transformation for transmission on the codec layer signals; and
generating a layered division multiplexed broadcast signal by combining multiplexer layer signals corresponding to the plurality of codec layer signals at different power levels;
The codec layer signals include a base layer signal and an enhancement layer signal, the base layer signal corresponds to a core layer signal of the layered division multiplexing, and the enhancement layer signal is an enhanced layer signal of the layered division multiplexing. corresponded,
The step of generating the broadcast signal
generating a power-reduced enhanced layer signal by reducing the power of the enhanced layer signal;
generating a multiplexed signal by combining the core layer signal and the power reduced enhanced layer signal by layered division multiplexing (LDM); and
lowering the power of the multiplexed signal to a power corresponding to the core layer signal,
The generating of the power-reduced enhanced layer signal reduces the power of the enhanced layer signal based on a scaling factor,
The step of lowering the power corresponding to the core layer signal reduces the power of the multiplexed signal based on a normalizing factor,
The method of claim 1, wherein the scaling factor and the normalizing factor change in opposite directions according to a change in power reduction in the step of generating the corresponding power-reduced enhanced layer signal. 15. The method of claim 14,
The scalable video content broadcasting method according to claim 1, wherein the codec layer signals correspond to the layers of the layered division multiplexing 1:1. delete 16. The method of claim 15,
The step of generating the broadcast signal
generating a time interleaved signal by performing interleaving applied to the core layer signal and the enhanced layer signal together; and
generating a broadcast signal frame corresponding to the layered division multiplexed broadcast signal using the time interleaved signal and L1 signaling information
Scalable video content broadcasting method further comprising a. 15. The method of claim 14,
The step of generating the multiplexed signal includes
The scalable video content broadcasting method, characterized in that the core layer signal and one or more extension layer signals having a lower power level than the enhanced layer signal are combined with the core layer signal and the enhanced layer signal. 19. The method of claim 18,
The codec layer signals further include an additional enhancement layer signal,
The scalable video content broadcasting method, wherein the additional enhancement layer signal corresponds to the extension layer signal. 15. The method of claim 14,
The codec layer signals include a base layer signal and two or more enhancement layer signals, the base layer signal corresponds to the core layer signal of the layered division multiplexing, and the enhancement layer signals are the enhanced layer of the layered division multiplexing A method for broadcasting scalable video content corresponding to a signal.

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