TECHNICAL FIELD

The present invention relates to broadcast signal transmission/reception technology that is used in a broadcasting system and, more particularly, to a broadcast signal transmission/reception system that multiplexes/demultiplexes and then transmits/receives two or more signals.

BACKGROUND ART

Bit-Interleaved Coded Modulation (BICM) is bandwidth-efficient transmission technology, and is implemented in such a manner that an error-correction coder, a bit-by-bit interleaver and a high-order modulator are combined with one another.

BICM can provide excellent performance using a simple structure because it uses a low-density parity check (LDPC) coder or a Turbo coder as the error-correction coder. Furthermore, BICM can provide high-level flexibility because it can select modulation order and the length and code rate of an error correction code in various forms. Due to these advantages, BICM has been used in broadcasting standards, such as DVB-T2 and DVB-NGH, and has a strong possibility of being used in other next-generation broadcasting systems.

To support multiple services at the same time, multiplexing, i.e., the process of mixing a plurality of signals, is required. Of multiplexing techniques, currently widely used techniques include Time Division Multiplexing (TDM) adapted to divide and use time resources and Frequency Division Multiplexing (FDM) adapted to divide and use frequency resources. That is, TDM is a method of assigning time segments to respective services, and FDM is a technique for assigning frequency resource segments to respective services and then using them. Recently, there is an urgent need for new multiplexing technology that is applicable to a next generation broadcasting system and provides greater flexibility and performance than TDM and FDM.

DISCLOSURE

Technical Problem

An object of the present invention is to provide a broadcast signal frame structure in which new signal multiplexing technologies capable of providing greater flexibility and performance than TDM and FDM are applied.

Furthermore, an object of the present invention is to enable each service to use 100% of time and frequency resources while supporting multiple services in a next generation broadcasting system at the same time.

Furthermore, an object of the present invention is to efficiently multiplex/demultiplex signals corresponding to two or more layers by combining the signals at respective different power levels.

Furthermore, an object of the present invention is to efficiently signaling layers which are combined at power levels different from each other and Physical Layer Pipes (PLPs).

Technical Solution

In order to accomplish the above objects, the present invention provides an apparatus for generating broadcast signal frame, including: a combiner configured to generate a multiplexed signal by combining a core layer signal and an enhanced layer signal at different power levels; a power normalizer configured to reduce the power of the multiplexed signal to a power level corresponding to the core layer signal; a time interleaver configured to generate a time-interleaved signal by performing interleaving that is applied to both the core layer signal and the enhanced layer signal; and a frame builder configured to generate a broadcast signal frame including a preamble for signaling, size information of Physical Layer Pipes (PLPs) and time interleaver information shared by the core layer signal and the enhanced layer signal.

In this case, the frame builder may include a bootstrap generator configured to generate a bootstrap; a preamble generator configured to generate the preamble; and a super-imposed payload generator configured to generate a super-imposed payload corresponding to the time-interleaved signal.

In this case, the size information may be generated based on the number of data cells assigned to the Physical Layer Pipe.

In this case, the preamble may include start position information and type information of the Physical Layer Pipes.

In this case, the preamble may include a PLP identification information for identifying the Physical Layer Pipes (PLPs); and a layer identification information for identifying layers corresponding to division of layers.

In this case, the size information and the start position information may be included in the preamble for each of the Physical Layer Pipes (PLPs) without checking a condition of a conditional statement corresponding to the layer identification information.

In this case, the type information may be selectively included in the preamble based on a result of comparing the layer identification information with a predetermined value for each of the Physical Layer Pipes (PLPs).

In this case, the apparatus may further include an injection level controller configured to generate a power-reduced enhanced layer signal by reducing the power of the enhanced layer signal. In this case, the combiner may generate the multiplexed signal by combining the core layer signal and the power-reduced enhanced layer signal.

In this case, the preamble may selectively include an injection level information corresponding to the injection level controller for each of the Physical Layer Pipes (PLPs) based on a result of comparing the layer identification information with a predetermined value.

In this case, the power normalizer may correspond to a normalizing factor, and may reduce the power of the multiplexed signal by a level by which the power has been increased by the combiner.

In this case, the injection level controller may correspond to a scaling factor. In this case, each of the normalizing factor and the scaling factor may be a value that is larger than 0 and smaller than 1, the scaling factor may decrease as a reduction in power corresponding to the injection level controller becomes larger, and the normalizing factor may increase as a reduction in power corresponding to the injection level controller becomes larger.

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

Furthermore, an embodiment of the present invention provides a method of generating broadcast signal frame, including: generating a multiplexed signal by combining a core layer signal and an enhanced layer signal at different power levels; reducing the power of the multiplexed signal to a power level corresponding to the core layer signal; generating a time-interleaved signal by performing interleaving that is applied to both the core layer signal and the enhanced layer signal; and generating a broadcast signal frame including a preamble for signaling, size information of Physical Layer Pipes (PLPs) and time interleaver information shared by the core layer signal and the enhanced layer signal.

In this case, the generating the broadcast signal frame may include generating a bootstrap; generating the preamble; and generating a super-imposed payload corresponding to the time-interleaved signal.

In this case, the size information may be generated based on the number of data cells allocated to the Physical Layer Pipe.

In this case, the preamble may include start position information and type information of the Physical Layer Pipes.

In this case, the preamble may include a PLP identification information for identifying Physical Layer Pipes (PLPs); and a layer identification information for identifying layers corresponding to division of layers.

In this case, the size information and the start position information may be included in the preamble for each of the Physical Layer Pipes (PLPs) without checking a condition of a conditional statement corresponding to the layer identification information.

In this case, the type information may be selectively included in the preamble based on a result of comparing the layer identification information with a predetermined value for each of the Physical Layer Pipes (PLPs).

Advantageous Effects

According to the present invention, a frame structure in which new signal multiplexing technologies capable of providing greater flexibility and performance than TDM and FDM is provided.

Furthermore, according to the present invention, multiple services can be supported in a next generation broadcasting system at the same time, and also each of the services can use 100% of time and frequency resources.

Furthermore, according to the present invention, signals corresponding to two or more layers can be efficiently multiplexed/demultiplexed by combining the signals at respective different power levels.

Furthermore, according to the present invention, layers which are combined at power levels different from each other and Physical Layer Pipes (PLPs) are efficiently signaled.

