JP7658798B2 - Transmitting device and receiving device - Google Patents

Description

The present invention relates to a transmitting device and a receiving device.

A transmission method is specified for a transmission frame in which a main signal and an SC (Service Channel) signal are multiplexed from a first device (e.g., a broadcasting station's studio or transmitting station) to a second device (e.g., a transmitting station). The main signal includes a first broadcast signal (e.g., a TS (Transport Stream) signal, a TMCC (Transmission and Multiplexing. Configuration Control) signal, etc.) related to terrestrial digital television broadcasting and V-Low terrestrial multimedia broadcasting. In such a transmission method, the link between the first device and the second device is called an STL (Studio To Transmitter Link) or a TTL (Transmitter To Transmitter Link) (e.g., Non-Patent Document 1).

"Digital STL/TTL Transmission System for Digital Terrestrial Broadcasting" Standard ARIB STD-B22 Version 2.1

In recent years, with the advancement of STL/TTL, technology (advanced STL/TTL) that multiplexes a second broadcast signal related to the advanced terrestrial broadcasting system onto a transmission frame is being considered. It is expected that the first broadcast signal and the second broadcast signal will be multiplexed onto the transmission frame used in advanced STL/TTL.

In light of this background, the inventors, after thorough investigation, have noted that the first rate of the first broadcast signal and the second rate of the second broadcast signal are different, and have discovered the need to appropriately guarantee the first rate and the second rate when multiplexing the first broadcast signal and the second broadcast signal into a transmission frame.

The present invention has been made to solve the above-mentioned problems, and aims to provide a transmitting device and a receiving device that make it possible to multiplex two or more broadcast signals into a transmission frame while appropriately ensuring the rates of the two or more broadcast signals.

The disclosed transmitting device transmits a multiplex transmission frame in which two or more broadcast signals are multiplexed, and includes a control unit that divides each of the two or more broadcast signals into predetermined units and multiplexes the two or more broadcast signals divided into the predetermined units based on the ratio of the rates of the two or more broadcast signals.

The disclosed receiving device is a receiving device that receives a multiplex transmission frame in which two or more broadcast signals are multiplexed, and includes a control unit that separates the two or more broadcast signals, which are separated into predetermined units, based on the ratio of the rates of the two or more broadcast signals.

The present invention provides a transmitting device and a receiving device that can multiplex two or more broadcast signals into a transmission frame while appropriately ensuring the rates of the two or more broadcast signals.

FIG. 1 is a diagram showing a digital wireless transmission system 10 according to an embodiment. FIG. 2 is a diagram showing a transmitting device 100 according to an embodiment. FIG. 3 is a diagram showing a receiving device 200 according to the embodiment. FIG. 4 is a diagram showing an FEC block according to the embodiment. FIG. 5 is a diagram showing the multiplexing unit 130 according to the embodiment. FIG. 6 is a diagram showing a separation unit 230 according to the embodiment. FIG. 7 is a diagram showing a multiplexing section 150 according to the first modification. FIG. 8 is a diagram showing a separator 250 according to the first modification.

Next, an embodiment of the present invention will be described. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the ratios of the dimensions may differ from the actual ones.

Therefore, specific dimensions should be determined with reference to the following explanation. Of course, there are also parts in which the dimensional relationships and ratios differ between the drawings.

[Disclosure Summary]
A transmitting device according to the disclosure outlines a transmitting device that transmits a multiplex transmission frame in which two or more broadcast signals are multiplexed, and includes a control unit that divides each of the two or more broadcast signals into predetermined units and multiplexes the two or more broadcast signals divided by the predetermined units based on a ratio of the rates of each of the two or more broadcast signals.

The receiving device according to the disclosure outlines a receiving device that receives a multiplex transmission frame in which two or more broadcast signals are multiplexed, and includes a control unit that separates the two or more broadcast signals, which are separated into predetermined units, based on the ratio of the rates of the two or more broadcast signals.

In the summary of the disclosure, a transmitting device multiplexes two or more broadcast signals separated by a predetermined unit based on the ratio of the rates of the two or more broadcast signals. A receiving device separates two or more broadcast signals separated by a predetermined unit based on the ratio of the rates of the two or more broadcast signals. With this configuration, even in cases where the rates of the two or more broadcast signals are different, it is possible to multiplex two or more broadcast signals into a transmission frame while appropriately ensuring the rates of the two or more broadcast signals.

Although not particularly limited, the predetermined unit may be a unit consisting of error correction blocks, a unit consisting of bytes, or a unit consisting of packets.

[Embodiment]
(Digital wireless transmission system)
A digital wireless transmission system according to an embodiment will be described below. Fig. 1 is a diagram showing a digital wireless transmission system 10 according to an embodiment. As shown in Fig. 1, the digital wireless transmission system includes a transmitting device 100 and a receiving device 200.

In an embodiment, in a case where two or more broadcast signals having different rates are transmitted from the transmitting device 100, the present invention relates to a system that transmits a multiplex transmission frame in which two or more broadcast signals are multiplexed from the transmitting device 100 to the receiving device 200. The transmitting device 100 may multiplex and transmit two or more broadcast signals in the form of an OFDM (Orthogonal Frequency Division Multiplexing) frame.

The location where the transmitting device 100 is installed may be a broadcasting station's studio or a transmitting station. The location where the receiving device 200 is installed may be a transmitting station. The link between the transmitting device 100 and the receiving device 200 may be referred to as an STL (Studio To Transmitter Link) or as a TTL (Transmitter To Transmitter Link). Hereinafter, the link between the transmitting device 100 and the receiving device 200 may be referred to as an STL/TTL.

In the embodiment, a case is described in which the two or more broadcast signals include a first broadcast signal and a second broadcast signal. The rate of the second method for the second broadcast signal may be greater than the rate of the first method for the first broadcast signal. The broadcast signals may be referred to as program transmission signals.

The first broadcast signal may include broadcast signals related to terrestrial digital television broadcasting and V-Low terrestrial multimedia broadcasting, such as a TS (Transport Stream) signal and a TMCC (Transmission and Multiplexing. Configuration Control) signal. The first broadcast signal may include an SC (Service Channel) signal, which is an auxiliary signal such as a control signal or a contact signal. The first system may be referred to as an ISDB-T (Integrated Services Digital Broadcasting-Terrestrial) system.

The second broadcast signal may include a second broadcast signal related to an advanced terrestrial broadcasting standard. The advanced terrestrial broadcasting standard may be an example of the second standard. The second broadcast signal may include a Service Channel (SC) signal.

Although not particularly limited, the first broadcast signal may be represented in the form of TS packets, and the rate of the TS packets may be 31 Mbps. The second broadcast signal may be represented in the form of IP packets, and the rate of the IP packets may be 50 Mbps. The IP packets may be read as program transmission signal packets.

(Transmitting device)
A transmitting device according to an embodiment will be described below. Fig. 2 is a block diagram showing a transmitting device 100 according to an embodiment.

As shown in FIG. 2, the transmitting device 100 has a block configuration unit 101, an energy dispersal unit 102, an outer code processing unit 103, an outer interleaver 105, an inner code processing unit 107, an inner interleaver 109, a mapping unit 110, a frame configuration unit 111, a modulation unit 113, and a transmitting unit 115.

The block configuration unit 101 configures an error correction block. The error correction block is a block to which FEC (Forward Error Correction) is applied, and may be referred to as an FEC block. The FEC block may have a fixed length. In the embodiment, a case is illustrated in which the block configuration unit 101 configures the FEC block of the first broadcast signal and the FEC block of the second broadcast signal separately. The FEC block of the first broadcast signal and the FEC block of the second broadcast signal may be fixed-length FEC blocks having the same length.

The energy dispersal unit 102 randomizes the bit sequence output from the block configuration unit 101 (i.e., the block header, the main signal (TS packet/IP packet), and the stuff bits if there are stuff bits before the BCH code parity of the FEC block) using a PN sequence generated using a generator polynomial of a predetermined dimension. Here, the initial value input to the generator polynomial is given for each FEC block. In other words, the PN sequence may be reset for each FEC block.

The outer code processing unit 103 performs error correction coding using the outer code. A BCH code may be used as the outer code. In the following, a case where the outer code is a BCH code is exemplified. The order of processing by the energy dispersal unit 102 and the outer code processing unit 103 may be reversed. In that case, the bit sequence randomized by the energy dispersal includes the block header, the main signal (TS packet/IP packet), stuff bits, and BCH code parity.

The outer interleaver 105 performs interleaving of the bit sequence or byte sequence output from the outer code processing unit 103. Interleaving is a process of rearranging the order of bits or bytes. The outer interleaver 105 may be omitted.

The inner code processing unit 107 performs error correction coding using the inner code. As the inner code, a low-density parity-check code (LDPC) may be used. In the following, a case where the inner code is an LDPC is illustrated.

The inner interleaver 109 performs interleaving of the sequence output from the inner code processing unit 107. The interleaving may include bit interleaving, which changes the order of bits. It may also include frequency interleaving, which changes the order in the frequency axis direction in units of the number of modulation bits, and may also include time interleaving, which changes the order in the time axis direction in units of the number of modulation bits.

The mapping unit 110 performs mapping on the sequence output from the inner interleaver 109 in units of the number of modulation bits. 64QAM (Quadrature Amplitude Modulation) may be used as the modulation method. A modulation method other than 64QAM (for example, up to 4096QAM) may also be used as the modulation method.

The frame configuration unit 111 configures a multiplexed transmission frame in which two or more broadcast signals are multiplexed. In an embodiment, the multiplexed transmission frame may include an FEC block of the first broadcast signal and an FEC block of the second broadcast signal. The multiplexed transmission frame may be an OFDM frame. In the case of an OFDM frame, the data mapped by the mapping unit 110, the pilot, TMCC, AC (Auxiliary Channel), and Null carriers are combined to configure an OFDM symbol. Furthermore, an OFDM frame is configured with a predetermined number of symbols per OFDM frame.

The modulation unit 113 performs orthogonal modulation on the multiplexed transmission frame. In the case of an OFDM frame, the modulation unit 113 performs IFFT (Inverse Fast Fourier Transform) and GI (Guard Interval) addition processing before performing orthogonal modulation.

The transmitter 115 transmits the multiplexed transmission frame modulated by the modulator 113 to the receiver 200. The transmitter 115 may have a function of converting an IF (Intermediate Frequency) signal into an RF (Radio Frequency) signal and amplifying it to a rated transmission power.

(Receiving device)
A receiving device according to an embodiment will be described below. Fig. 3 is a block diagram showing a receiving device 200 according to an embodiment.

As shown in FIG. 3, the receiving device 200 has a receiving unit 201, a demodulation unit 203, a frame processing unit 205, a demapping unit (likelihood calculation unit) 206, an inner deinterleaver 207, an inner code processing unit 209, an outer deinterleaver 211, an outer code processing unit 213, an energy despreading unit 214, and a block processing unit 215.

The receiving unit 201 receives a multiplexed transmission frame from the transmitting device 100. The receiving unit 201 may have a function of converting an RF signal into an IF signal. The receiving unit 201 may receive an OFDM frame as the multiplexed transmission frame.

The demodulation unit 203 performs orthogonal demodulation on the multiplexed transmission frame. In the case of an OFDM frame, after orthogonal demodulation, GI removal and FFT processing are performed.

The frame processing unit 205 detects the beginning of the multiplex transmission frame and synchronizes the multiplex transmission frame. In the case of an OFDM frame, it detects the beginning of the OFDM frame from information on the TMCC carrier that can be differentially demodulated, and extracts the OFDM symbol.

The demapping unit (likelihood calculation unit) 206 performs equalization of the propagation path, and then performs demapping on the data according to the modulation method. When performing soft decision, it calculates the likelihood.

The inner deinterleaver 207 performs deinterleaving in the reverse procedure to that of the inner interleaver 109. The deinterleaving may include bit deinterleaving, frequency deinterleaving, and time deinterleaving.

The inner code processing unit 209 performs error correction of the FEC block based on the LDPC code parity. The inner code processing unit 209 removes the LDPC code parity from the FEC block.

The outer deinterleaver 211 performs deinterleaving in the reverse order to that of the outer interleaver 105.

The outer code processor 213 performs error correction of the FEC block based on the BCH code parity. The outer code processor 213 removes the BCH code parity from the FEC block and any stuff bits that are present after the BCH code parity of the FEC block.

The energy despreading unit 214 performs energy despreading in the reverse procedure to that of the energy diffusion unit 102. The target of energy despreading is the bit sequence output from the outer code processing unit 213 (i.e., the block header, the main signal (TS packet/IP packet), and the stuff bit if there is a stuff bit before the BCH code parity of the FEC block). Here, the initial value input to the generator polynomial is given for each FEC block. In other words, the PN sequence may be reset for each FEC block.

The block processing unit 215 separates the block header and the main signal (TS packets/IP packets) from the FEC block. Specifically, the block processing unit 215 extracts the TS packets from the FEC block of the first broadcast signal, and extracts the IP packets from the FEC block of the second broadcast signal.

(FEC block)
The FEC block according to the embodiment will be described below. Fig. 4 is a diagram showing the FEC block according to the embodiment.

As shown in Example 1 of Figure 4, an FEC block includes a block header, a main signal, stuff bits, BCH code parity, and LDPC code parity. The use of the block header is arbitrary. The type of main signal of the FEC block may be described in the block header. As shown in Example 2 of Figure 4, the order of the BCH code parity and stuff bits may be reversed.

Although not particularly limited, the size of the main signal (D) may vary according to the coding rate of the LDPC. The size of the LDPC code parity (P _ldpc ) may vary according to the coding rate of the LDPC. The number of TS packets or IP packets included as the main signal may vary according to the coding rate of the LDPC.

(Multiple Processing)
The multiplexing process according to the embodiment will be described below. In the embodiment, a case will be described in which the first broadcast signal and the second broadcast signal are multiplexed in units of FEC blocks.

As shown in FIG. 5, the multiplexing unit 130 has a buffer 131A, a buffer 131B, a stuff packet 132A, a stuff packet 132B, a switching unit 133A, a switching unit 133B, an FEC block construction unit 134A, an FEC block construction unit 134B, and a switching unit 135.

The multiplexing unit 130 is an example of a control unit that divides each of the two or more broadcast signals by the length of the main signal of the FEC block, which is a predetermined unit, and multiplexes the two or more broadcast signals divided by the predetermined unit based on the ratio of the rates of the two or more broadcast signals. The multiplexing unit 130 is provided in the block configuration unit 101 of the transmitting device 100.

Buffer 131A is a buffer that stores the first broadcast signal. For example, buffer 131A stores TS packets having a rate of 31 Mbps.

Buffer 131B is a buffer that stores the second broadcast signal. For example, buffer 131B stores IP packets having a rate of 50 Mbps.

Stuff packet 132A outputs a stuff packet when the first broadcast signal for forming one TS packet is not stored in buffer 131A.

Stuff packet 132B outputs a stuff packet when the second broadcast signal for forming one IP packet is not stored in buffer 131B.

The switching unit 133A switches the source of the packets to be stored in the FEC block of the first broadcast signal. Specifically, the switching unit 133A switches the source for inputting packets to the FEC block construction unit 134A between the buffer 131A and the stuff packet 132A.

The switching unit 133B switches the source of the packets to be stored in the FEC block of the second broadcast signal. Specifically, the switching unit 133B switches the source for inputting packets to the FEC block construction unit 134B between the buffer 131B and the stuff packet 132B.

The FEC block constructing unit 134A constructs an FEC block of the first broadcast signal. It stores block header information in the block header of the FEC block, and stores a predetermined unit of packets or stuff packets of the first broadcast signal output from the switching unit 133A in the main signal portion of the FEC block.

The FEC block constructing unit 134B constructs an FEC block of the second broadcast signal. It stores block header information in the block header of the FEC block, and stores a predetermined unit of packets or stuff packets of the second broadcast signal output from the switching unit 133B in the main signal portion of the FEC block.

The switching unit 135 switches the source of the FEC block multiplexed into the multiplex transmission frame. Specifically, the switching unit 135 switches the source of the FEC block multiplexed into the multiplex transmission frame between the FEC block composition unit 134A and the FEC block composition unit 134B.

Here, the switching unit 135 determines the allocation of the number of FEC blocks in the multiplex transmission frame based on the ratio of the rates of two or more broadcast signals (e.g., "31:50" ≒ "3:5"), and switches the source of the FEC blocks. For example, the switching unit 135 may switch the source of the FEC blocks so that five inputs of FEC blocks of the second broadcast signal are obtained for three inputs of FEC blocks of the first broadcast signal. Specifically, the switching unit 135 may switch in the order of ABBABBAB, with A being the case when FEC block configuration unit 134A is selected, and B being the case when FEC block configuration unit 134B is selected.

(Separation process)
The following describes the separation process according to the embodiment: In the embodiment, a case will be described in which the first broadcast signal and the second broadcast signal are separated in units formed by FEC blocks.

As shown in FIG. 6, the separation unit 230 has a switching unit 231, an FEC block processing unit 232A, an FEC block processing unit 232B, a stuff packet removal unit 233A, and a stuff packet removal unit 233B.

The separation unit 230 is an example of a control unit that separates two or more broadcast signals separated by a predetermined unit based on the ratio of the rates of the two or more broadcast signals. The separation unit 230 is provided in the block processing unit 215 of the receiving device 200.

The switching unit 231 switches the target of the FEC block separated from the multiplex transmission frame. Specifically, the switching unit 231 switches the target of the FEC block separated from the multiplex transmission frame between the FEC block processing unit 232A and the FEC block processing unit 232B.

Here, the switching unit 231 switches the target of the FEC block in a predetermined order based on the ratio of the rates of the two or more broadcast signals (for example, "31:50" ≒ "3:5"). For example, the switching unit 231 may switch the source of the FEC block so that an output of five FEC blocks of the second broadcast signal is obtained for an output of three FEC blocks of the first broadcast signal. The switching unit 231 may identify the FEC block of the first broadcast signal and the FEC block of the second broadcast signal by checking the block header of the FEC block. The FEC block processing unit 232A extracts the first broadcast signal (TS packets) or stuff packets of the main signal from the FEC block of the first broadcast signal.

The FEC block processing unit 232B extracts the second broadcast signal (IP packets) or stuff packets of the main signal from the FEC block of the second broadcast signal.

The stuff packet removal unit 233A removes stuff packets from the main signal output from the FEC block processing unit 232A and extracts the first broadcast signal (TS packets).

The stuff packet removal unit 233B removes stuff packets from the main signal output from the FEC block processing unit 232B and extracts the second broadcast signal (IP packets).

(Action and Effects)
In the embodiment, the transmitting device 100 multiplexes two or more broadcast signals divided into units each composed of an FEC block based on the ratio of the rates of the two or more broadcast signals. The receiving device 200 separates two or more broadcast signals divided into units each composed of an FEC block based on the ratio of the rates of the two or more broadcast signals. With this configuration, even if the rates of the two or more broadcast signals are different, it is possible to multiplex two or more broadcast signals into a transmission frame while appropriately ensuring the rates of the two or more broadcast signals.

[Modification 1]
Modification 1 of the embodiment will be described below. Differences from the embodiment will be mainly described below.

In the embodiment, multiplexing and demultiplexing of the first broadcast signal and the second broadcast signal are performed in units formed by FEC blocks. In contrast, a case will be described in which multiplexing and demultiplexing of the first broadcast signal and the second broadcast signal are performed in units formed by bytes.

(Multiple Processing)
The following describes the multiplexing process according to Modification 1. In Modification 1, a case will be described in which the first broadcast signal and the second broadcast signal are multiplexed in units of bytes.

As shown in FIG. 7, the multiplexing unit 150 has a buffer 151A, a buffer 151B, a stuff packet 152A, a stuff packet 152B, a switching unit 153A, a switching unit 153B, a switching unit 154, and an FEC block construction unit 155.

The multiplexing unit 150 is an example of a control unit that divides each of the two or more broadcast signals into bytes, which are a predetermined unit, and multiplexes the two or more broadcast signals divided into the predetermined units based on the ratio of the rates of the two or more broadcast signals. The multiplexing unit 150 is provided in the block configuration unit 101 of the transmitting device 100.

Buffer 151A is a buffer that stores the first broadcast signal. For example, buffer 151A stores TS packets having a rate of 31 Mbps.

Buffer 151B is a buffer that stores the second broadcast signal. For example, buffer 151B stores IP packets having a rate of 50 Mbps.

The stuff packet 152A outputs a stuff packet when the first broadcast signal for forming one TS packet is not stored in the buffer 131A. The stuff packet output from the stuff packet 152A may be considered to be dummy data equivalent to the first broadcast signal.

The stuff packet 152B outputs a stuff packet when the second broadcast signal for forming one IP packet is not stored in the buffer 131B. The stuff packet output from the stuff packet 152B may be considered to be dummy data equivalent to the second broadcast signal.

The switching unit 153A switches the source of the packets to be stored in the FEC block. Specifically, the switching unit 153A switches the source for inputting packets to the switching unit 154 between the buffer 151A and the stuff packet 152A.

The switching unit 153B switches the source of the packets to be stored in the FEC block. Specifically, the switching unit 153B switches the source for inputting packets to the switching unit 154 between the buffer 151B and the stuff packet 152B.

The switching unit 154 switches the source of the data multiplexed into the FEC block on a byte-by-byte basis. Specifically, the switching unit 154 switches the source of the data multiplexed into the FEC block between the switching unit 153A and the switching unit 153B.

Here, the switching unit 154 switches the data source based on the ratio of the rates of two or more broadcast signals (for example, "31:50" ≒ "3:5"). For example, the switching unit 154 may switch the data source so that an input of 5 bytes of second broadcast signal data is obtained for an input of 3 bytes of first broadcast signal data. Specifically, the switching unit 154 may switch in the order of ABBABBAB, with A being the case when switching unit 153A is selected and B being the case when switching unit 153B is selected.

The FEC block constructing unit 155 constructs an FEC block in which the first broadcast signal and the second broadcast signal are multiplexed. The FEC block constructing unit 155 stores block header information in the block header of the FEC block, and stores the byte-unit signal output from the switching unit 154 in the main signal portion of the FEC block.

In the embodiment, the FEC block of the first broadcast signal and the FEC block of the second broadcast signal are separate, so the FEC block configuration unit is processed in two systems. In contrast, in the first modification, the first broadcast signal and the second broadcast signal are multiplexed into one FEC block, so the FEC block configuration unit is processed in one system.

(Separation process)
The following describes the separation process according to Modification Example 1. In Modification Example 1, a case will be described in which the first broadcast signal and the second broadcast signal are separated in units of bytes.

As shown in FIG. 8, the separation unit 250 has an FEC block processing unit 251, a switching unit 252, a stuff packet removal unit 253A, and a stuff packet removal unit 253B.

The separation unit 250 is an example of a control unit that separates two or more broadcast signals separated by a byte, which is a predetermined unit, based on the ratio of the rates of the two or more broadcast signals. The separation unit 250 is provided in the block processing unit 215 of the receiving device 200.

The FEC block processing unit 251 extracts the main signal in which the first broadcast signal (TS packets), the second broadcast signal (IP packets), and their stuff packets are multiplexed on a byte-by-byte basis from the FEC block.

In the embodiment, the FEC block of the first broadcast signal and the FEC block of the second broadcast signal are separate, so the FEC block processing unit processes in two systems. In contrast, in the first modification, the first broadcast signal and the second broadcast signal are multiplexed into one FEC block, so the FEC block processing unit processes in one system.

The switching unit 252 switches the target of the data separated from the FEC block. Specifically, the switching unit 252 switches the target of the data separated from the FEC block between the processing unit for the first broadcast signal and the processing unit for the second broadcast signal.

Here, the switching unit 252 switches the data target in a predetermined order based on the ratio of the rates of two or more broadcast signals (for example, "31:50" ≒ "3:5"). For example, the switching unit 252 may switch the data target so that an output of 5 bytes of second broadcast signal data is obtained for an output of 3 bytes of first broadcast signal data.

(Action and Effects)
In the first modification, the transmitting device 100 multiplexes two or more broadcast signals separated into units formed by bytes based on the ratio of the rates of the two or more broadcast signals. The receiving device 200 separates two or more broadcast signals separated into units formed by bytes based on the ratio of the rates of the two or more broadcast signals. With this configuration, even in a case where the rates of the two or more broadcast signals are different, it is possible to multiplex two or more broadcast signals into a transmission frame while appropriately ensuring the rates of the two or more broadcast signals.

In the first modification, the predetermined unit to which multiplexing or demultiplexing is applied is a unit consisting of bytes. With this configuration, delays in the first broadcast signal or the second broadcast signal can also be suppressed.

[Modification 2]
The second modification of the embodiment will be described below, focusing mainly on the differences from the first modification.

In the first modification, multiplexing and demultiplexing of the first and second broadcast signals are performed in units of bytes. In contrast, a case will be described in which multiplexing and demultiplexing of the first and second broadcast signals are performed in units of packets (TS packets or IP packets).

Here, the TS packets constituting the first broadcast signal may have a fixed length (e.g., 204 bytes). The IP packets constituting the second broadcast signal may have a fixed length (e.g., 1500 bytes). The length (number of bytes) of the TS packets may differ from the length (number of bytes) of the IP packets, but the ratio of the length of the TS packets to the length of the IP packets may be determined in advance or by TMCC.

Essentially, in Modification Example 2, the "bytes" described in Modification Example 1 should be read as "packets." However, the above-mentioned switching unit 154 and switching unit 252 may also operate as follows.

The switching unit 154 switches the data source based on the ratio of the rates of two or more broadcast signals (e.g., "31:50" ≒ "3:5"). For example, the switching unit 154 switches the data source based on the ratio of the length of the first broadcast signal (TS packets) and the length of the second broadcast signal (IP packets) so that the ratio of the rates of two or more broadcast signals is maintained.

Similarly, the switching unit 252 switches the data source based on the ratio of the respective rates of two or more broadcast signals (e.g., "31:50" ≒ "3:5"). For example, the switching unit 252 switches the data source based on the ratio of the length of the first broadcast signal (TS packets) and the length of the second broadcast signal (IP packets) so that the ratio of the respective rates of the two broadcast signals is maintained.

In the second modification, the switching unit 252 may identify the TS packets of the first broadcast signal and the IP packets of the second broadcast signal by checking the packet headers of the packets (TS packets or IP packets).

[Other embodiments]
Although the present invention has been described by the above disclosure, the description and drawings forming a part of this disclosure should not be understood as limiting the present invention. From this disclosure, various alternative embodiments, examples and operating techniques will become apparent to those skilled in the art.

The above disclosure has exemplified a case in which two broadcast signals are multiplexed into a multiplex transmission frame. However, the above disclosure is not limited to this. The above disclosure may also be applied to a case in which three or more broadcast signals are multiplexed into a multiplex transmission frame.

In the above disclosure, the predetermined unit to which multiplexing or demultiplexing is applied is exemplified as a unit consisting of FEC blocks, a unit consisting of bytes, or a unit consisting of packets. However, the above disclosure is not limited to this. The predetermined unit to which multiplexing or demultiplexing is applied may be any unit that can maintain the ratio of the respective rates of two or more broadcast signals.

Although not specifically mentioned in the above disclosure, a program may be provided that causes a computer to execute each process performed by the transmitting device 100 and the receiving device 200. The program may also be recorded on a computer-readable medium. Using the computer-readable medium, it is possible to install the program on a computer. Here, the computer-readable medium on which the program is recorded may be a non-transient recording medium. The non-transient recording medium is not particularly limited, and may be, for example, a recording medium such as a CD-ROM or a DVD-ROM.

Alternatively, a chip may be provided that is configured with a memory that stores programs for executing the processes performed by the transmitting device 100 and the receiving device 200, and a processor that executes the programs stored in the memory.

10...digital wireless transmission system, 100...transmitting device, 101...block configuration section, 102...energy diffusion section, 103...outer code processing section, 105...outer interleaver, 107...inner code processing section, 109...inner interleaver, 110...mapping section, 111...frame configuration section, 113...modulation section, 115...transmitting section, 130...multiplexing section, 131...buffer, 132...stuff packet, 133...switching section, 134...FEC block configuration section, 135...switching section, 150...multiplexing section, 151...buffer, 152...stuff packet, 153...switching section, 154...switching unit, 155...FEC block construction unit, 200...receiving device, 201...receiving unit, 203...demodulation unit, 205...frame processing unit, 206...demapping unit (likelihood calculation unit), 207...inner deinterleaver, 209...inner code processing unit, 211...outer deinterleaver, 213...outer code processing unit, 214...energy despreading unit, 215...block processing unit, 230...separation unit, 231...switching unit, 232...FEC block processing unit, 233...stuff packet removal unit, 250...separation unit, 251...FEC block processing unit, 252...switching unit, 253...stuff packet removal unit

Claims (2)

A transmitting device for transmitting a multiplex transmission frame in which two or more broadcast signals are multiplexed, comprising:
A transmitting device comprising: a control unit that divides each of the two or more broadcast signals into units each consisting of a byte, and multiplexes the two or more broadcast signals divided into units each consisting of a byte into a main signal portion of an error correction block based on a ratio of the rates of the two or more broadcast signals. A receiving device for receiving a multiplex transmission frame in which two or more broadcast signals are multiplexed, comprising:
A receiving device comprising a control unit that separates the two or more broadcast signals, each divided into units consisting of bytes , from a main signal portion of an error correction block based on a ratio of the rates of the two or more broadcast signals.

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