Transmitting device, receiving device and program

Abstract

To immediately resume defragmentation processing without reducing transmission efficiency even when a communication error occurs.SOLUTION: A pointer information addition unit 20 equipped in a transmission unit 11 of a transmitting / receiving device 2 deletes a preamble from an IP packet, and generates pointer information including a payload length of the IP packet, to be added thereto. A packet division unit 21 divides the packet with the pointer information into a size of RS packet length excluding a synchronization byte, to generate RS packet data. A synchronization byte addition unit 22 generates a synchronization byte by embedding information on a storage position of the pointer information in information identifying an RS packet and a video signal, to be added to the RS packet data, thereby generating an RS packet. An error detection (correction) code is added to the RS packet, the RS packet is modulated, and a frequency of a modulation signal is converted and the like, therefore a modulation wave is transmitted to a radio section 3.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a transmitting device that transmits packets, a receiving device that receives packets, and a program. [Background technology]

[0002] Conventionally, there is a method called IP over TS as a method for transmitting TCP / IP (Transmission Control Protocol / Internet Protocol) IP packets as an MPEG2-TS stream of video signals used in terrestrial digital broadcasting and the like.

[0003] In the IP over TS technique, processes called fragmentation and defragmentation are performed to transmit variable-length IP packets as fixed-length TS packets.

[0004] Fragmentation is a process in which a transmitting device divides an IP packet into packets of a size that can be transmitted by a TS packet, and then adds a header to identify each packet. Defragmentation is a process in which a receiving device analyzes the header of a received TS packet and restores the divided IP packets. Non-patent documents 1 and 2 are examples of standards related to such fragmentation.

[0005] A method has been proposed in Patent Application Publication No. 2020-93605, made by the same applicant as this patent application and unpublished at the time of filing this patent application, as a technology for multiplexing and transmitting MPEG2-TS video signals while transmitting IP signals using a method similar to IP over TS.

[0006] Figure 11 is a diagram showing an example of fragmentation in the method of Patent Application No. 2020-93605, Figure 12 is a diagram showing an example of the configuration of synchronization bytes and pointer information in the same method, and Figure 13 is a diagram showing an example of defragmentation in the same method.

[0007] In the following, a case will be described in which a Reed-Solomon (RS) code is used as an error correction code for signal transmission in a wireless section, and the transmission unit in the wireless section is an RS packet having the same length as a TS packet.

[0008] The payload of an IP packet means 64 to 1522 bytes of data other than the 8-byte preamble, the payload of an RS packet means data other than the synchronization byte and pointer information, and the payload of an MPEG2-TS packet means 187 bytes of data other than the synchronization byte.

[0009] With reference to FIG. 11, on the transmitting side, IP packets to be multiplexed are fragmented in units of RS packets and then transmitted, while MPEG2-TS packets, which are video signals, are transmitted as they are as RS packets.

[0010] When fragmenting on the sending side, the 8-byte preamble included in the IP packet is deleted, and the payload portion of the IP packet is divided into pieces of a size that can be transmitted by RS packets. When the IP packet is divided, pointer information is added to the beginning of the payload. Then, a synchronization byte is added to the beginning of the RS packet.

[0011] 11, the payload of an IP packet IP-1 is divided into three. Then, one byte of synchronization byte (0x21) and two bytes of pointer information are added to the 185-byte payload to generate a 188-byte RS packet RS-1 consisting of the synchronization byte, pointer information, and payload data d1.

[0012] Similarly, one synchronization byte (0xDE) is added to the 187-byte payload to generate a 188-byte RS packet RS-2 consisting of the synchronization byte and payload data d2.

[0013] Also, the payload of IP packet IP-2 is divided into a predetermined number of pieces equal to or greater than 2. A 1-byte synchronization byte (0xDE) and 2-byte pointer information are added to the remaining payload (payload data d3) divided from IP packet IP-1 and the first payload (payload data d4) divided from IP packet IP-2. As a result, a 188-byte RS packet RS-3 consisting of the synchronization byte, payload data d3, pointer information, and payload data d4 is generated.

[0014] Meanwhile, a synchronization byte (0x47, 0xB8) is added to each of the payloads of 187-byte MPEG2-TS packets, and a 188-byte RS packet consisting of the synchronization byte and the payload of the MPEG2-TS packet is generated.

[0015] The payload length of the IP packet is stored in the pointer information, and for example, the pointer information is added before the leading payload data d4 divided from the IP packet IP-2, and an RS packet is generated.

[0016] Then, the RS packet is subjected to error correction coding using an RS code to generate a coded RS packet, which is then modulated and converted into a radio frequency signal, and the modulated wave is transmitted via a transmitting antenna.

[0017] Referring to FIG. 12, the sync byte is made up of 8 bits and takes one of the values ​​0x47, 0xB8, 0x21, 0xDE, and 0xFF.

[0018] If the sync byte is 0x47 or 0xB8, it indicates that it is an MPEG2-TS sync byte. If it is 0x21, it indicates that the beginning of the RS packet excluding the sync byte is pointer information. If it is 0xDE, it indicates that there is no pointer information at the beginning of the RS packet excluding the sync byte.

[0019] Also, if an error correction decoding error occurs on the receiving side, the "RS packet loss information" is stored in the synchronization byte to indicate that the RS packet is an error packet. In other words, if the synchronization byte is 0xFF, it indicates that it is "RS packet loss information."

[0020] The pointer information is made up of a total of 16 bits, including the data type (2 bits) following the pointer information in the RS packet, spare (3 bits), and the payload length of the IP packet (11 bits). The data type indicates an Ethernet packet, padding, or test data (PN signal, etc.).

[0021] With reference to FIG. 13, on the receiving side, an RS packet is generated by performing error correction decoding on a modulated wave signal received via a receiving antenna.

[0022] In the defragmentation on the receiving side, the sync byte and pointer information contained in the RS packet are analyzed to determine the payload length of the IP packet. Then, data of the IP packet payload length is extracted from the RS packet, the IP packet payload is reconstructed, the pointer information is deleted, and a preamble is added. This restores the IP packet.

[0023] Moreover, MPEG2-TS packets, which are video signals, are generated from the RS packets, thereby restoring the video signal.

[0024] As shown in Fig. 12, multiplex transmission is realized by identifying the type of RS packet by the value of the synchronization byte. That is, if the RS packet stores an MPEG2-TS payload, which is a video signal, the value of the synchronization byte is 0x47 or 0xB8. Also, if the RS packet stores an IP packet payload, the value of the synchronization byte is 0x21 or 0xDE.

[0025] In this way, by analyzing the value of the synchronization byte on the receiving side, it becomes possible to identify the type of RS packet and realize multiplex transmission. Note that the synchronization byte of 0x21 or 0xDE distinguishes whether or not there is pointer information at the beginning of the RS packet excluding the synchronization byte. [Prior art documents] [Non-patent literature]

[0026] [Non-Patent Document 1] IEEE Std 802.11, “Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications”, IEEE Standard, Mar. 2012. [Non-Patent Document 2] 3GPP TS 25.322, “Radio Link Control (RLC) protocol specification”, 3GPP Release 11, V11.2.0, Mar. 2013. Summary of the Invention [Problem to be solved by the invention]

[0027] In the defragmentation process in the method of the above-mentioned Japanese Patent Application No. 2020-93605, the receiving device obtains the payload length of the IP packet from the pointer information and identifies the range of the RS packet corresponding to the IP packet (which was divided from the same IP packet before being divided by the transmitting device).The receiving device then combines and cuts out the RS packet to restore the original IP packet.The receiving device repeats the defragmentation process, such as obtaining the payload length of the IP packet from the next pointer information.

[0028] However, if a communication error such as an RS decoding error occurs in an RS packet containing pointer information, the receiving device cannot immediately resume the defragmentation process, because the receiving device needs to immediately obtain the pointer information to restore the IP packet.

[0029] 13, when recovery from a communication error is made and detection of the beginning of an RS packet is resumed, and for example, an RS packet RS-1 including pointer information is correctly restored, the receiving device can determine that "pointer information is present at the beginning of the RS packet excluding the synchronization byte" by analyzing the synchronization byte (0x21) of the RS packet RS-1. In other words, since the receiving device can obtain the pointer information, it can immediately resume the defragmentation process.

[0030] In contrast, suppose that the communication error is recovered and the detection of the beginning of the RS packet is resumed, and for example, the RS packet RS-3 including the pointer information is correctly restored. In this case, even if the receiving device analyzes the synchronization byte (0xDE) of the RS packet RS-3, the position of the pointer information in the RS packet RS-3 is unknown, so the receiving device cannot obtain the pointer information and cannot immediately resume the defragmentation process.

[0031] In the method of the above-mentioned Japanese Patent Application No. 2020-93605, there is no guarantee that an RS packet including a synchronization byte (0x21) indicating that "pointer information is at the beginning excluding the synchronization byte" can be regularly received, and the position of the pointer information is not fixed within the RS packet. In other words, it is not always possible to immediately obtain pointer information after recovery from a communication error.

[0032] For this reason, the receiving device needs to wait for the RS packet RS-1 shown in FIG. 13 (an RS packet including a sync byte (0x21) indicating that "the head excluding the sync byte is pointer information").

[0033] To solve this problem, it is conceivable that, for example, information regarding the location where the pointer information is stored would be stored in the header, so that all RS packets would have the location information of the pointer information. However, this method would result in a problem that the header length would be long, reducing transmission efficiency.

[0034] Therefore, the present invention has been made to solve the above-mentioned problems, and its object is to provide a transmitting device, a receiving device, and a program that can immediately resume defragmentation processing without reducing transmission efficiency even if a communication error occurs. [Means for solving the problem]

[0035] In order to solve the above problem, a transmitting device according to claim 1 receives an IP packet and a video signal, generates RS packets from the IP packet and the video signal, respectively, to which a synchronization byte is added, modulates the RS packet by adding an error detection code capable of detecting an error or an error correction code capable of correcting an error, and transmits a modulated wave. The transmitting device includes a pointer information adding unit that receives the IP packet, deletes a preamble from the IP packet, generates pointer information including a payload length of the IP packet, and adds the pointer information to the IP packet from which the preamble has been deleted, thereby generating a packet consisting of the pointer information and the payload of the IP packet; and a packet division unit which generates RS packet data by dividing the packets generated by the packet division unit into a predetermined size; and a synchronization byte addition unit which inputs the RS packet data generated by the packet division unit and the video signal, generates the synchronization byte based on the RS packet data and the video signal, and generates the RS packet by adding the synchronization byte to each of the payloads of the RS packet data and the video signal, wherein the synchronization byte addition unit generates the synchronization byte which indicates information for identifying the RS packet data and the video signal, and in the case of the RS packet data, indicates information for determining the position of the pointer information in the RS packet.

[0036] In addition, the transmitting device of claim 2 is characterized in that, in the transmitting device described in claim 1, the synchronization byte addition unit, when inputting the video signal, generates the synchronization byte indicating that it is the video signal, when inputting the RS packet data including the pointer information, generates the synchronization byte indicating that the RS packet contains the pointer information and the position of the pointer information, and when inputting the RS packet data not including the pointer information, generates the synchronization byte indicating that the RS packet does not contain the pointer information.

[0037] Furthermore, the transmitting device of claim 3 is characterized in that, in the transmitting device described in claim 1 or 2, it further comprises a frame generating unit that generates a frame including modulated signals of a predetermined number of the RS packets generated by the modulation, and transmits the modulated wave of the frame generated by the frame generating unit.

[0038] Furthermore, the receiving device of claim 4 receives a modulated wave of an RS packet to which a synchronization byte has been added, decodes the RS packet by demodulation and error detection including error detection or correction, and restores an IP packet and a video signal from the RS packet, and is characterized in that it comprises: a synchronization byte analysis unit that extracts the synchronization byte from the RS packet, and extracts RS packet data excluding the synchronization byte from the RS packet, and if the synchronization byte indicates information that identifies the video signal, restores and outputs the video signal from the RS packet, and if the synchronization byte indicates information that identifies the RS packet and information that determines a position of pointer information in the RS packet, extracts the pointer information from the RS packet, a pointer information analysis unit that obtains a payload length of the IP packet from the pointer information extracted by the synchronization byte analysis unit, and a packet combination unit that combines the RS packet data extracted by the synchronization byte analysis unit according to the payload length of the IP packet obtained by the pointer information analysis unit, deletes the pointer information from the combined RS packet data, and adds a preamble to generate the IP packet.

[0039] In addition, the receiving device of claim 5 is characterized in that, in the receiving device described in claim 4, the receiving device further includes a frame demodulation unit that, when receiving a modulated wave of a frame including a predetermined number of the RS packets, demodulates the frame from the received signal of the modulated wave and extracts the modulated signal of the predetermined number of the RS packets from the frame.

[0040] The program of claim 6 further comprises a computer constituting a transmitting device that receives an IP packet and a video signal, generates RS packets to which a synchronization byte is added from the IP packet and the video signal, modulates the RS packet by adding an error detection code capable of detecting an error or an error correction code capable of correcting an error to the RS packet, and transmits a modulated wave, the computer comprising: a pointer information adding unit that receives the IP packet, deletes a preamble from the IP packet, generates pointer information including a payload length of the IP packet, and adds the pointer information to the IP packet from which the preamble has been deleted to generate a packet consisting of the pointer information and the payload of the IP packet; a packet division unit that generates RS packet data by dividing a video signal into a predetermined size, and a synchronization byte addition unit that inputs the RS packet data generated by the packet division unit and the video signal, generates the synchronization byte based on the RS packet data and the video signal, and adds the synchronization byte to each of the payloads of the RS packet data and the video signal to generate the RS packet, wherein the synchronization byte addition unit generates the synchronization byte, which is information that identifies the RS packet data and the video signal, and in the case of the RS packet data, indicates information that determines the position of the pointer information in the RS packet.

[0041] The program of claim 7 is characterized in that it causes a computer constituting a receiving device that receives a modulated wave of an RS packet to which a synchronization byte has been added, decodes the RS packet by demodulation and error detection including error detection or correction, and restores an IP packet and a video signal from the RS packet to function as a synchronization byte analysis unit that extracts the synchronization byte from the RS packet, extracts RS packet data excluding the synchronization byte from the RS packet, and, if the synchronization byte indicates information that identifies the video signal, restores and outputs the video signal from the RS packet, and, if the synchronization byte indicates information that identifies the RS packet and indicates information that determines the position of pointer information in the RS packet, extracts the pointer information from the RS packet, if the synchronization byte indicates information that identifies the RS packet and indicates information that determines the position of pointer information in the RS packet, extracts the pointer information from the RS packet, a pointer information analysis unit that acquires the payload length of the IP packet from the pointer information extracted by the synchronization byte analysis unit, and a packet combination unit that combines the RS packet data extracted by the synchronization byte analysis unit according to the payload length of the IP packet acquired by the pointer information analysis unit, deletes the pointer information from the combined RS packet data, and adds a preamble to generate the IP packet. Effect of the Invention

[0042] As described above, according to the present invention, even if a communication error occurs, the defragmentation process can be immediately resumed without reducing transmission efficiency. [Brief description of the drawings]

[0043] [Figure 1] 1 is a schematic diagram showing an overall configuration of a transmission / reception system including a transmission / reception device (a transmission device and a reception device) according to an embodiment of the present invention. [Diagram 2] 2 is a block diagram showing a configuration example of a transmission / reception device; [Diagram 3] 4 is a block diagram showing an example of the configuration of a transmission unit; FIG. [Figure 4] 13 is a flowchart illustrating an example of processing by a transmission unit. [Diagram 5]FIG. 13 is a diagram illustrating an example of a fragment. [Figure 6] FIG. 13 is a diagram illustrating an example of the configuration of a synchronization byte. [Figure 7] 1A is a diagram showing an example of the configuration of an RS packet, and FIG. 1B is a diagram showing an example of the configuration of an RS packet when it includes two or more pieces of pointer information. [Figure 8] 4 is a block diagram showing a configuration example of a receiving unit; FIG. [Figure 9] 13 is a flowchart illustrating an example of processing by a receiving unit. [Figure 10] FIG. 13 illustrates an example of defragmentation. [Figure 11] FIG. 13 is a diagram showing an example of a fragment in the method of Japanese Patent Application No. 2020-93605. [Figure 12] A figure showing an example of the configuration of synchronization bytes and pointer information in the method of Patent Application No. 2020-93605. [Figure 13] A figure showing an example of defragmentation using the method of Japanese Patent Application No. 2020-93605. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0044] Hereinafter, the embodiment of the present invention will be described in detail with reference to the drawings. The present invention is characterized in that a synchronization byte added to the header of an RS packet is used to distinguish between an IP packet and an MPEG2-TS packet, which is a video signal, and to determine the position where pointer information is stored. This synchronization byte is data in which information for determining the position where pointer information is stored is embedded in information for distinguishing between an IP packet and an MPEG2-TS packet, which is a video signal.

[0045] This allows the location where the pointer information is stored to be stored in all RS packets without increasing the size of the header of the RS packet. Therefore, when a communication error such as an RS decoding error occurs in an RS packet including pointer information on the receiving side and the communication error is recovered, the pointer information can be immediately obtained from the RS packet, so that the defragmentation process can be immediately resumed without reducing the transmission efficiency.

[0046] [Transmitting and Receiving System] First, the overall configuration of the transmission / reception system will be described. Fig. 1 is a schematic diagram showing the overall configuration of a transmission / reception system including a transmission / reception device (a transmission device and a reception device) according to an embodiment of the present invention. This transmission / reception system 1 is configured with a transmission / reception device 2-1 and a transmission / reception device 2-2. The transmission / reception device 2-1 and the transmission / reception device 2-2 are connected to each other via a wireless section 3.

[0047] Although two transmitting / receiving devices 2-1 and 2-2 are shown in FIG. 1 for convenience of explanation, the transmitting / receiving system 1 may be configured with three or more transmitting / receiving devices 2-1, 2-2, etc.

[0048] The transmitting / receiving devices 2-1, 2-2 (hereinafter collectively referred to as the "transmitting / receiving device 2") have a transmitting function and a receiving function. The transmitting function is a function that generates RS packets from IP packets and MPEG2-TS packets, which are video signals, by fragmentation processing, and transmits modulated waves of the RS packets. The receiving function is a function that receives modulated waves of the RS packets, and restores IP packets and MPEG2-TS packets from the RS packets by defragmentation processing.

[0049] The wireless section 3 is a network using wireless communication such as time division duplex, frequency division duplex, etc. The transmitting / receiving device 2-1 and the transmitting / receiving device 2-2 may be connected to each other via a network using wired communication such as Ethernet (registered trademark) instead of the wireless section 3.

[0050] [Configuration of Transmitter / Receiver 2] 2 is a block diagram showing an example of the configuration of the transmission / reception device 2. The transmission / reception device 2 includes an interface unit 10, a transmission unit (transmission device) 11, and a reception unit (reception device) 12.

[0051] When the transmitting / receiving device 2 functions as a transmitting device, the interface unit 10 inputs IP packets and video signals (MPEG2-TS packets) and outputs the IP packets and video signals to the transmitting unit 11. On the other hand, when the transmitting / receiving device 2 functions as a receiving device, the interface unit 10 inputs IP packets and video signals from the receiving unit 12 and outputs the IP packets and video signals. Note that the interface unit 10 may be divided into two, an input interface unit and an output interface unit.

[0052] The transmitter 11 receives the IP packet and the video signal from the interface unit 10, deletes the preamble from the IP packet, and adds pointer information. The transmitter 11 then divides the packet with the added pointer information into pieces of a predetermined size according to the size of the RS packet (or RS packet data), and generates an RS packet by adding a synchronization byte (described later) to the divided data of the predetermined size. Here, the RS packet data means 187 bytes of data of the RS packet excluding the synchronization byte.

[0053] Furthermore, the transmitter 11 generates an RS packet by using the synchronization byte of the MPEG2-TS packet, which is a video signal, as the synchronization byte of the RS packet and using the payload of the MPEG2-TS packet as the payload of the RS packet. The transmitter 11 then modulates the RS packet by adding an error detection (correction) code. The modulated wave of the RS packet generated by such fragmentation processing is transmitted via an antenna. The transmitter 11 will be described in detail later.

[0054] The receiver 12 receives the modulated wave transmitted from the other transmitter / receiver 2 via an antenna, demodulates the received signal, and detects (corrects) errors to restore the RS packet. The receiver 12 then analyzes the synchronization byte and pointer information to combine the payload data of the RS packet, deletes the pointer information, and adds a preamble to restore the IP packet.

[0055] The receiving unit 12 analyzes the synchronization byte to determine the RS packet in which the video signal is stored, and restores the video signal from the RS packet. The receiving unit 12 outputs the IP packet and the video signal restored by such defragmentation processing to the interface unit 10. The receiving unit 12 will be described in detail later.

[0056] (Transmitter 11) Next, a description will be given of details of transmission unit 11 shown in Fig. 2. Fig. 3 is a block diagram showing an example of the configuration of transmission unit 11, Fig. 4 is a flowchart showing an example of processing by transmission unit 11, and Fig. 5 is a diagram showing an example of fragmentation.

[0057] The transmitting section 11 includes a pointer information adding section 20, a packet dividing section (fragmenting section) 21, a synchronization byte adding section 22, an error detection (correction) code adding section 23, a modulating section 24, and a high frequency section and antenna 25, etc.

[0058] The pointer information adding unit 20 inputs an IP packet from the interface unit 10 (step S401). Then, the pointer information adding unit 20 deletes the preamble from the IP packet, and generates the pointer information shown in FIG. 12 by determining the payload length of the IP packet (the payload of the IP packet) from which the preamble has been deleted.

[0059] The pointer information adding unit 20 adds pointer information to the IP packet from which the preamble has been deleted, thereby generating a packet to which the pointer information has been added (a packet consisting of the pointer information and the payload of the IP packet) (step S402). The pointer information adding unit 20 outputs the packet to which the pointer information has been added to the packet dividing unit 21.

[0060] As shown in FIG. 12, the pointer information includes the payload length of the IP packet and the type of data following the pointer information in the RS packet.

[0061] The packet dividing unit 21 inputs the packet to which the pointer information has been added from the pointer information adding unit 20. Then, the packet dividing unit 21 divides the packet to which the pointer information has been added into the size of the RS packet length excluding the synchronization byte (the size of the RS packet data length, 187 bytes) (by performing fragmentation processing) to generate RS packet data (187 bytes) (step S403). The packet dividing unit 21 outputs the RS packet data to the synchronization byte adding unit 22. As described above, this RS packet data means 187 bytes of data from the RS packet excluding the synchronization byte at the beginning.

[0062] In the example of FIG. 5, it is assumed that pointer information is added to an IP packet IP-1 from which the preamble has been deleted, and that pointer information is added to an IP packet IP-2 from which the preamble has been deleted.

[0063] In this case, the first packet (2 bytes+64 to 1522 bytes packet) to which pointer information has been added is divided into three, and the second packet to which pointer information has been added is divided into two or more. As a result, the first RS packet data consisting of pointer information and payload data d1, the second RS packet data consisting of payload data d2, and the third RS packet data consisting of payload data d3, pointer information and payload data d4 are generated.

[0064] In addition, if the size of the IP packet is smaller than that of the RS packet, the packet division unit 21 combines each of the packets to which pointer information has been added (the payload of the IP packet to which pointer information has been added) and regards this as RS packet data (187 bytes).

[0065] The synchronization byte adding unit 22 inputs the RS packet data from the packet dividing unit 21 and also inputs the video signal from the interface unit 10 (step S404). Then, the synchronization byte adding unit 22 generates a synchronization byte shown in Fig. 6, which will be described later, based on the RS packet data and the video signal.

[0066] Specifically, the synchronization byte adding unit 22 judges whether or not the input RS packet data includes pointer information, and if the pointer information is included, judges its position.

[0067] When the RS packet data includes pointer information, the synchronization byte adding unit 22 generates a synchronization byte (one of the values ​​of 0x00 to 0x46, 0x48 to 0xB7, and 0xB9 to 0xBB shown in FIG. 6, which will be described later) indicating that the RS packet data includes pointer information and indicating the position of the pointer information. When the RS packet data does not include pointer information, the synchronization byte adding unit 22 generates a synchronization byte (0xFE shown in FIG. 6, which will be described later) indicating that the RS packet does not include pointer information.

[0068] The packet division unit 21 generates information regarding whether or not the RS packet data includes pointer information and the position of the pointer information in the RS packet data from a series of processes for generating RS packet data by dividing the packet with the pointer information added thereto into the size of the RS packet data length. The synchronization byte addition unit 22 judges whether or not the RS packet data includes pointer information and the position of the pointer information in the RS packet data based on the information.

[0069] On the other hand, the synchronization byte adding unit 22 uses the synchronization byte included in the MPEG2-TS packet, which is the input video signal, as it is as the synchronization byte (0x47, 0xB8) of the RS packet.

[0070] The synchronization byte adding unit 22 adds a synchronization byte to the RS packet data, and also adds a synchronization byte to the payload of the video signal to generate an RS packet (step S405). The synchronization byte adding unit 22 outputs the RS packet to the error detection (correction) code adding unit 23.

[0071] Fig. 6 is a diagram showing an example of the configuration of a synchronization byte, and Fig. 7(1) is a diagram showing an example of the configuration of an RS packet. Referring to Fig. 6, the synchronization byte is made up of 8 bits and takes any one of the values ​​0x47, 0xB8, 0x00 to 0x46, 0x48 to 0xB7, 0xB9 to 0xBB, 0xFE, and 0xFF.

[0072] When the value of the synchronization byte is 0x47 or 0xB8, it indicates that the synchronization byte is an MPEG2-TS synchronization byte. When the value of the synchronization byte is 0x00 to 0x46, 0x48 to 0xB7, or 0xB9 to 0xBB (186 possible values), it indicates that the RS packet contains pointer information, and indicates the start position of the pointer information.

[0073] As shown on the right side of Figure 6, for example, if the value of the synchronization byte is 0x00, this indicates that the length from the beginning of the RS packet excluding the synchronization byte to the start position of the pointer information is 0 bytes as "information on the start position of the pointer information." In this case, the pointer information is located at the position following the synchronization byte at the beginning of the RS packet.

[0074] For example, if the value of the synchronization byte is 0x46, this indicates that the length from the beginning of the RS packet excluding the synchronization byte to the start position of the pointer information is 70 bytes, as shown in Fig. 7 (1). In this case, the pointer information is located at a position 70 bytes, which is the length from the beginning of the RS packet excluding the synchronization byte to the start position of the pointer information.

[0075] Returning to the right side of FIG. 6, similarly, for example, if the value of the synchronization byte is 0xBB, this indicates that the length from the beginning of the RS packet excluding the synchronization byte to the start position of the pointer information is 185 bytes.

[0076] In the example of fragmentation shown in Fig. 5, the RS packet data of RS packet RS-1 consists of pointer information and payload data d1, which is a part of the payload of IP packet IP-1, so the length from the beginning of RS packet RS-1 excluding the synchronization byte to the start position of the pointer information is 0 bytes. In this case, a synchronization byte with a value of "0x00" is generated and added to this RS packet data.

[0077] Also, since the RS packet data of the RS packet RS-2 is payload data d2, which is a part of the payload of the IP packet IP-1, this RS packet data does not include pointer information. In this case, a synchronization byte with a value of "0xFE" is generated and added to this RS packet data.

[0078] The RS packet data of the RS packet RS-3 consists of payload data d3, which is a part of the payload of the IP packet IP-1, pointer information, and payload data d4, which is a part of the payload of the IP packet IP-2. In this case, if the length from the beginning of the RS packet RS-3 excluding the synchronization byte to the start position of the pointer information is, for example, 71 bytes, a synchronization byte with a value of "0x48" is generated and added to this RS packet data.

[0079] The synchronization byte in the method of Patent Application No. 2020-93605 shown in Figure 12 is used to distinguish between IP packets and video signals, and in the case of IP packets, is used to determine whether or not there is pointer information at a specified position within the RS packet (the position at the beginning of the RS packet excluding the synchronization byte).

[0080] In contrast, the synchronization byte in the embodiment of the present invention shown in Figure 6 is used to distinguish between IP packets and video signals, and is also used to determine the specific location where the pointer information is stored within the RS packet.

[0081] In other words, when comparing the synchronization byte in an embodiment of the present invention with the synchronization byte in the method of Patent Application No. 2020-93605, they have in common that they contain information for identifying IP packets and video signals (type of RS packets).

[0082] On the other hand, in the case of an IP packet, when the RS packet contains pointer information, the synchronization byte in the embodiment of the present invention indicates information on the start position of the pointer information, and one of 186 values ​​of 0x00 to 0x46, 0x48 to 0xB7, and 0xB9 to 0xBB is used. Also, when the RS packet does not contain pointer information, the value of the synchronization byte is 0xFE. In this respect, the synchronization byte in the embodiment of the present invention differs from the synchronization byte in the method of Japanese Patent Application No. 2020-93605.

[0083] 7(2) is a diagram showing an example of the configuration of an RS packet including two or more pieces of pointer information. The payload length of an IP packet ranges from 64 to 1522 bytes. For this reason, for example, when the payload length of an IP packet is a minimum value of 64 bytes, one RS packet may include two or more pieces of pointer information.

[0084] In the example of Figure 7 (2), the synchronization byte stores the start position of the first pointer information, that is, the pointer information that is closer to the synchronization byte (the starting position of the pointer information that is closest to the synchronization byte) among two or more pointer information ("0x0A", indicating that it is 10 bytes).

[0085] In this case, in the process of step S405 in Fig. 4, synchronization byte adding unit 22 determines the positions of multiple pieces of pointer information for the RS packet data input from packet dividing unit 21. Then, synchronization byte adding unit 22 determines the position of the pointer information closest to the beginning among the positions of the multiple pieces of pointer information, and generates a synchronization byte (0x0A in the example of Fig. 7(2)) for the relevant pointer information, which indicates that the RS packet data contains pointer information and indicates the position of the pointer information.

[0086] In this way, when receiving RS packet data from packet divider 21, sync byte addition unit 22 generates a sync byte indicating the length from the start position of the RS packet data (the start position of the RS packet excluding the sync byte) to the start position of the pointer information. Here, when the RS packet data includes two or more pieces of pointer information, sync byte addition unit 22 generates a sync byte indicating the length from the start position of the RS packet data to the start position of the pointer information closest to the start position of the RS packet data. Then, sync byte addition unit 22 generates an RS packet by adding a sync byte to the start of the RS packet data.

[0087] On the other hand, when the synchronization byte addition unit 22 inputs a video signal from the interface unit 10, it uses the synchronization byte (0x47, 0xB8) of the MPEG2-TS packet, which is the video signal, as the synchronization byte of the RS packet, and generates an RS packet (188 bytes) by adding a synchronization byte (1 byte) to the payload (187 bytes) of the video signal.

[0088] 3 to 5, the error detection (correction) code addition unit 23 inputs the RS packet from the synchronization byte addition unit 22, and adds an error detection code capable of detecting an error or an error correction code capable of correcting an error to the RS packet (step S406). Then, the error detection (correction) code addition unit 23 outputs the coded RS packet to the modulation unit 24. Here, the type of error correction code is not particularly important, and a code in which an error detection code and an error correction code are concatenated may be added to the RS packet.

[0089] The modulation unit 24 inputs the coded RS packet from the error detection (correction) code addition unit 23. The modulation unit 24 modulates the coded RS packet to make it a signal that can be transmitted wirelessly, and the high frequency unit and antenna etc. 25 converts the frequency of the modulated signal to a wireless frequency, and transmits the modulated wave to the wireless section 3 via the antenna (step S407).

[0090] As described above, according to the transmission / reception device 2 of the embodiment of the present invention, the pointer information addition unit 20 of the transmission unit 11 deletes the preamble from the IP packet, generates pointer information including the payload length of the IP packet, and adds the pointer information to the IP packet from which the preamble has been deleted.

[0091] The packet division unit 21 divides the packet to which the pointer information has been added into packets having a size of an RS packet length excluding a synchronization byte, thereby generating RS packet data.

[0092] When the synchronization byte addition unit 22 inputs RS packet data, it determines whether the RS packet data contains pointer information, and if the pointer information is included, it determines its position, and generates a synchronization byte indicating that "the RS packet contains pointer information" and representing "information on the starting position of the pointer information", or a synchronization byte indicating that "the RS packet does not contain pointer information".

[0093] When a video signal is input, the synchronization byte adding unit 22 generates a synchronization byte for identifying the video signal. Then, the synchronization byte adding unit 22 generates an RS packet by adding the synchronization byte to the payload of the RS packet data and the video signal.

[0094] Then, an error detection (correction) code is added to the RS packet, modulation is performed, the frequency of the modulated signal is converted, and the modulated wave is transmitted to the wireless section 3 via the antenna.

[0095] As a result, the position information of the pointer information is stored in the synchronization byte of the RS packet, so that the receiving unit 12 provided in another transmitting / receiving device 2 that receives the modulated wave transmitted by the transmitting unit 11 can obtain the pointer information from the RS packet based on the position information of the pointer information stored in the synchronization byte.

[0096] That is, even if a communication error such as an RS decoding error occurs in an RS packet including pointer information, when the communication error is recovered, the receiver 12 can immediately obtain the pointer information from the RS packet from the timing when the detection of the beginning of the RS packet is resumed and when the RS packet including the pointer information is first received.The receiver 12 can then immediately perform a defragmentation process to combine the RS packets by, for example, determining the payload length of the IP packet from the pointer information.

[0097] In contrast, in the method of Patent Application No. 2020-93605 shown in Fig. 12, the position of the pointer information cannot be determined from the synchronization byte. In the example shown in Fig. 13, when a communication error occurs in RS packet RS-3 and the communication error is recovered from, the synchronization byte of RS packet RS-3 merely indicates that there is no pointer information at the beginning excluding the synchronization byte, so the pointer information cannot be obtained. In other words, even if the communication error is recovered from, defragmentation processing cannot be performed immediately.

[0098] In the embodiment of the present invention, the position of the pointer information can be determined from the synchronization byte. In the same example as that shown in Figure 5, when a communication error occurs in the RS packet RS-3 and the communication error is recovered, the pointer information can be obtained from the synchronization byte of the RS packet RS-3. In other words, when the communication error is recovered, the defragmentation process can be performed immediately.

[0099] In addition, because the synchronization byte is used to distinguish IP packets from video signals and to determine the position of the pointer information, there is no need for all RS packets to have pointer information in addition to the synchronization byte, and therefore the header information of the RS packet does not increase.

[0100] In general, when adding the position information of the pointer information to the RS packet, it is necessary to prepare this position information separately from the synchronization byte that distinguishes the IP packet from the video signal. In the embodiment of the present invention, the position information of the pointer information is embedded in the synchronization byte without changing the size of the synchronization byte. This prevents the transmission efficiency from decreasing.

[0101] Therefore, even if a communication error such as an RS decoding error occurs in an RS packet including pointer information, the defragmentation process can be immediately resumed without reducing transmission efficiency.

[0102] (Receiver 12) Next, a description will be given of the details of the receiving unit 12 shown in Fig. 2. Fig. 8 is a block diagram showing an example of the configuration of the receiving unit 12, Fig. 9 is a flowchart showing an example of the processing of the receiving unit 12, and Fig. 10 is a diagram showing an example of defragmentation.

[0103] The receiving unit 12 includes a radio frequency unit and antenna 30, a demodulation unit 31, an error detection (correction) unit 32, a synchronous byte analysis unit 33, a pointer information analysis unit , and a packet combining unit (defragmentation unit) .

[0104] The high frequency unit and antenna etc. 30 receives the modulated wave (the modulated wave of the RS packet with a synchronization byte added) transmitted from the transmitting unit 11 shown in FIG. 3 via an antenna, and outputs the modulated signal to the demodulation unit 31 by, for example, converting the radio frequency of the received signal to an intermediate frequency.

[0105] The demodulation unit 31 receives a modulated signal from the high frequency unit and antenna 30, demodulates the modulated signal, and outputs the demodulated packet to the error detection (correction) unit 32 (step S901).

[0106] The error detection (correction) unit 32 inputs the demodulated packet from the demodulation unit 31, performs error detection including error detection and correction on the packet, and decodes the RS packet, and determines whether the RS packet has been correctly decoded (step S902).

[0107] When the error detection (correction) unit 32 determines that the RS packet has been correctly decoded, it outputs the decoded RS packet and the decoding result indicating OK to the synchronous byte analysis unit 33. On the other hand, when the error detection (correction) unit 32 determines that the RS packet has not been correctly decoded, it outputs the RS packet before decoding and the decoding result indicating NG to the synchronous byte analysis unit 33.

[0108] The synchronous byte analysis unit 33 receives the RS packet and the decoded result from the error detection (correction) unit 32. Then, the synchronous byte analysis unit 33 judges whether the decoded result is OK or NG (step S903).

[0109] If the synchronization byte analysis unit 33 determines in step S903 that the decoding result is NG (step S903: NG), it writes “RS packet loss information” (0xFF) indicating a decoding failure to the synchronization byte of the RS packet (step S904), and proceeds to step S905.

[0110] On the other hand, if the synchronous byte analysis unit 33 determines in step S903 that the decoded result is OK (step S903: OK), the process proceeds to step S905. In this case, the synchronous byte analysis unit 33 uses the decoded synchronous byte as is.

[0111] The synchronization byte analysis unit 33 proceeds from step S903 (OK) or step S904, extracts the synchronization byte and RS packet data (data excluding the synchronization byte from the RS packet) from the RS packet, and analyzes the synchronization byte shown in FIG. 6 (determines the content of the synchronization byte) (step S905).

[0112] When the synchronous byte analyzer 33 determines that the synchronous byte indicates "an MPEG2-TS synchronous byte", it determines that the payload of an MPEG2-TS packet, which is a video signal, is stored in the RS packet. Then, the synchronous byte analyzer 33 generates a video signal from the RS packet and outputs a stream of the video signal (step S906). This restores the video signal.

[0113] On the other hand, if the synchronization byte analysis unit 33 determines that the synchronization byte indicates that "the RS packet contains pointer information" and represents "information on the start position of the pointer information" (if the value of the synchronization byte is any of 0x00 to 0x46, 0x48 to 0xB7, or 0xB9 to 0xBB (186 combinations)), it determines that the RS packet contains pointer information. Then, the synchronization byte analysis unit 33 extracts the pointer information from the RS packet based on the "information on the start position of the pointer information" indicated by the synchronization byte.

[0114] In the case of the example of the RS packet configuration shown in Figure 7(2), the RS packet includes two or more pieces of pointer information, and the synchronization byte stores "information on the starting position of the pointer information" for the pointer information that is closer to the synchronization byte (closest).

[0115] In this case, the synchronization byte analysis unit 33 extracts the first pointer information (the pointer information closer to the synchronization byte (the closest)) from the RS packet based on the "information on the start position of the pointer information" indicated by the synchronization byte. Then, the synchronization byte analysis unit 33 obtains the payload length of the IP packet from the pointer information, and determines whether the RS packet includes second or subsequent pointer information based on the payload length of the IP packet, the "information on the start position of the pointer information" indicated by the synchronization byte, the size of the pointer information (2 bytes), and the size of the RS packet data (187 bytes).

[0116] 7(2), the payload length of the IP packet obtained from the first pointer information is 100 bytes. The synchronization byte analysis unit 33 determines that the total of the payload length of the IP packet (100 bytes), the "information of the start position of the pointer information" (10 bytes) indicated by the synchronization byte, and the size of the pointer information (2 bytes), which is 112 bytes, is smaller than the size of the RS packet data (187 bytes), and determines that the second and subsequent pointer information are included in the RS packet.

[0117] Then, the synchronization byte analyzer 33 extracts the next 2 bytes of data after the first 112 bytes of the RS packet as pointer information. In this manner, the synchronization byte analyzer 33 extracts two or more pieces of pointer information from the RS packet.

[0118] The synchronous byte analyzer 33 outputs the RS packet data and the pointer information to the pointer information analyzer .

[0119] The pointer information analysis unit 34 inputs the RS packet data and the pointer information from the synchronous byte analysis unit 33, and analyzes the pointer information shown in Fig. 12 (determines the contents of the pointer information).The pointer information analysis unit 34 then acquires the payload length of the IP packet from the pointer information, and distributes the RS packet data to the corresponding IP packet based on the position of the pointer information in the RS packet data so that the payload data of the IP packet payload length thereafter corresponds to the IP packet (step S907).

[0120] The pointer information analysis unit 34 generates, for each RS packet data, distribution information indicating the relationship between the RS packet data and the IP packet to which it is to be distributed, and outputs the RS packet data and the distribution information to the packet combination unit 35.

[0121] In the example of defragmentation shown in Figure 10, RS packet data (pointer information and payload data d1) extracted from RS packet RS-1, RS packet data (payload data d2) extracted from RS packet RS-2, and RS packet data (payload data d3, pointer information and payload data d4 (actually only payload data d3)) extracted from RS packet RS-3 are assigned to IP packet IP-1.

[0122] Also, the RS packet data (payload data d3, pointer information and payload data d4 (actually pointer information and payload data d4)) extracted from the RS packet RS-3 is distributed to the IP packet IP-2. Distribution information indicating the relationship between such RS packet data and the IP packet is generated.

[0123] The packet combining unit 35 inputs the RS packet data and distribution information from the pointer information analysis unit 34, and if it determines based on the distribution information that multiple RS packets (RS packet data) correspond to one IP packet, it combines the corresponding multiple RS packet data.

[0124] The packet combining unit 35 generates an IP packet by deleting the pointer information from the combined RS packet data and adding a preamble to the beginning (step S908). This reconstructs the IP packet. When deleting the pointer information from the combined RS packet data, if the pointer information is located at a position other than the beginning of the RS packet data (other than the beginning of the combined RS packet data), the packet combining unit 35 deletes the data following the pointer information or the data before the pointer information from the combined RS packet data.

[0125] 10, when generating an IP packet IP-1, the packet combiner 35 deletes pointer information from a plurality of RS packet data extracted from and combined with the RS packets RS-1, RS-2, and RS-3, and deletes payload data d4 following the pointer information included in the RS packet data extracted from the RS packet RS-3 (payload data d3, pointer information, and payload data d4). When generating an IP packet IP-2, the packet combiner 35 deletes pointer information from a plurality of RS packet data extracted from the RS packets RS-3, etc., and deletes payload data d3, etc. preceding the pointer information included in the RS packet data extracted from the RS packet RS-3 (payload data d3, pointer information, and payload data d4).

[0126] 10, the RS packet data extracted from the RS packets RS-1, RS-2, and RS-3 are combined based on the distribution information. As a result, combined data consisting of the first pointer information (pointer information included in the RS packet RS-1), payload data d1, payload data d2 and d3, the second pointer information (pointer information included in the RS packet RS-3), and payload data d4 is generated.

[0127] Then, from this combined data, the first pointer information is deleted, and the second pointer information and payload data d4 are deleted, and a preamble is added to the beginning, thereby generating an IP packet IP-1.

[0128] In this case, since the second pointer information is located at a position other than the beginning of the RS packet data contained in the RS packet RS-3, the second pointer information and the following payload data d4 are deleted from the combined data. Whether the pointer information is located at the beginning of the RS packet data or at a position other than the beginning is determined by whether the value of the sync byte is 0x00 or not through the sync byte analysis process of the sync byte analyzer 33. It is assumed that the packet combiner 35 inputs the determination information for each RS packet data.

[0129] Furthermore, when the next IP packet IP-2 is generated, combined data consisting of payload data d3, the first pointer information (pointer information included in RS packet RS-3), payload data d4, and the like is generated.

[0130] Then, from this combined data, the first pointer information present in any position other than the beginning of the RS packet data is deleted, and the payload data d3 preceding this is deleted, and a preamble is added to the beginning, thereby generating an IP packet IP-2.

[0131] In this case, since the first pointer information is located at a position other than the beginning of the RS packet data contained in the RS packet RS-3, the first pointer information and the payload data d3 preceding it are deleted from the combined data.

[0132] 8 and 9, the packet combining unit 35 proceeds from step S908 and outputs the IP packet to the interface unit 10 (step S909). As a result, the IP packet is restored.

[0133] When the packet combining unit 35 determines based on the sorting information that one RS packet (RS packet data) is stored in multiple IP packets, it deletes each of the multiple pointer information from the RS packet data, and sets the RS packet data at the payload length of the IP packet indicated by each pointer information as the payload of the corresponding IP packet. The packet combining unit 35 generates multiple corresponding IP packets by adding a preamble to the beginning of the payload of each IP packet.

[0134] As described above, according to the transceiver 2 of the embodiment of the present invention, the high frequency section and antenna etc. 30 of the receiver 12 receives the modulated wave transmitted by the transmitter 11 provided in another transceiver 2, converts the radio frequency of the received signal, etc., the demodulator 31 performs demodulation, and the error detection (correction) section 32 performs error detection (correction), thereby decoding the RS packet.

[0135] If the decoded result of the RS packet is NG, the receiver 12 performs a retransmission process for each RS packet, a determination process such as discarding the RS packet, and so on.

[0136] The synchronization byte analysis unit 33 extracts the synchronization byte and RS packet data from the decoded RS packet, and if the synchronization byte indicates that "the RS packet contains pointer information" and represents "information on the start position of the pointer information", it extracts the pointer information from the RS packet based on the "information on the start position of the pointer information".

[0137] The pointer information analysis unit 34 obtains the payload length of the IP packet from the pointer information, and distributes the RS packet data to IP packets based on the position of the pointer information in the RS packet data so that the payload data of the IP packet's payload length thereafter corresponds to the IP packet, thereby generating distribution information.

[0138] The packet combining unit 35 combines a plurality of RS packet data based on the distribution information, deletes pointer information and the like, and adds a preamble to the beginning to generate an IP packet.

[0139] As a result, since the position information of the pointer information is stored in the synchronization byte of the RS packet, the pointer information can be obtained from the RS packet. That is, even if a communication error such as an RS decoding error occurs in the RS packet including the pointer information, when the communication error is recovered, the pointer information can be immediately obtained from the RS packet based on the synchronization byte from the timing after the detection of the head of the RS packet is resumed and from the timing of the first reception of the RS packet including the pointer information. Then, the payload length of the IP packet can be determined from the pointer information, and the defragmentation process for combining the RS packet can be immediately performed.

[0140] For example, in the method of Patent Application No. 2020-93605 shown in Fig. 12, the position of the pointer information cannot be determined from the synchronization byte. Therefore, in the example shown in Fig. 13, when a communication error occurs in RS packet RS-3 and the communication is restored, the pointer information cannot be obtained from the synchronization byte of RS packet RS-3, and defragmentation cannot be performed immediately.

[0141] In contrast, in the embodiment of the present invention, the position of the pointer information can be determined from the synchronization byte. Therefore, in the same example as that shown in Fig. 5, when a communication error occurs in RS packet RS-3 and then the communication is restored, the pointer information can be obtained from the synchronization byte of RS packet RS-3.

[0142] That is, in the embodiment of the present invention, it is possible to reliably obtain pointer information from an RS packet that contains the pointer information, and defragmentation processing can be performed immediately.

[0143] In addition, since this synchronization byte is used to distinguish between IP packets and video signals and to determine the position of the pointer information, there is no need for all RS packets to have pointer information position information, and the header information of the RS packets does not increase.

[0144] Therefore, even if a communication error such as an RS decoding error occurs in an RS packet including pointer information, the defragmentation process can be immediately resumed without reducing transmission efficiency.

[0145] Although the present invention has been described above with reference to the embodiments, the present invention is not limited to the above-described embodiments and can be modified in various ways without departing from the technical concept thereof.

[0146] In the above embodiment, a transmission / reception device 2 having a transmission unit 11 and a receiving unit 12 was described, but the transmission function of the present invention can also be applied to a transmission device having a transmission unit 11, and the receiving function can also be applied to a receiving device having a receiving unit 12.

[0147] In addition, although the synchronization byte is generally a fixed value, in the implementation of the transmission and reception functions of the present invention, the synchronization byte can take many values. Therefore, the value of the synchronization byte is likely to be indefinite, and the detection of the beginning of an RS packet using the synchronization byte may not work properly.

[0148] To solve this problem, the transmitter 11 of the transmitter / receiver 2 transmits a plurality of RS packets stored in, for example, a TDD (Time Division Duplex) frame. By using the TDD frame, the beginning of the transmission unit can be made to coincide with the beginning of the RS packet, making it possible to detect the beginning of the RS packet. In this case, the synchronization byte is not used to detect the synchronization position of the RS packet, but is simply used to indicate the beginning of the RS packet.

[0149] The receiving unit 12 of the other transmitting / receiving device 2 receives the TDD frame, reads out the multiple RS packets stored in the TDD frame, detects the first RS packet stored in the TDD frame, and detects the subsequent RS packets by using the size of the RS packet length as a criterion.

[0150] Specifically, in the configuration of the transmitting unit 11 shown in Figure 3, the transmitting unit 11 further includes a buffer unit between the synchronization byte addition unit 22 and the error detection (correction) code addition unit 23, and a TDD frame generation unit between the modulation unit 24 and the high-frequency unit and antenna, etc. 25.

[0151] This buffer section stores a preset number of RS packets (a predetermined number of RS packets that fit into the transmission unit of a TDD frame) taking into consideration the data amount of the error detection (correction) code added by the error detection (correction) code addition section 23. The TDD frame generation section generates a TDD frame including modulated signals of the predetermined number of RS packets, using this predetermined number of RS packets as a unit.

[0152] In this case, the transmitting unit 11 may include a buffer unit between the error detection (correction) code adding unit 23 and the modulating unit 24. This buffer unit stores a preset number of coded RS packets (a predetermined number of coded RS packets that fit within the transmission unit of a TDD frame) taking into consideration the data amount of the error detection (correction) code added by the error detection (correction) code adding unit 23.

[0153] 8, the receiving unit 12 further includes a TDD frame demodulation unit between the high frequency unit and antenna 30 and the demodulation unit 31.

[0154] The TDD frame demodulation unit demodulates the modulated signal input from the high frequency unit and antenna etc. 30 into a TDD frame, and detects the modulated signal of the first RS packet from the demodulated TDD frame, as well as the modulated signal of the following RS packet.

[0155] This makes it possible to detect the beginning of an RS packet without using a synchronization byte. Note that the present invention is not limited to a TDD frame, and frames other than a TDD frame may be used. In short, the frame in which a plurality of RS packets are stored may be any frame as long as it is possible to match the beginning of a transmission unit with an RS packet.

[0156] A typical computer can be used as the hardware configuration of the transmission / reception device 2 according to the embodiment of the present invention. The transmission / reception device 2 is configured by a computer including a CPU, a volatile storage medium such as a RAM, a non-volatile storage medium such as a ROM, an interface, and the like.

[0157] Each function of the interface unit 10, the transmitter unit 11, and the receiver unit 12 provided in the transmitter / receiver 2 is realized by causing a CPU to execute a program describing these functions. These programs are stored in the storage medium, and are read and executed by the CPU.

[0158] The same applies to a transmitting device having the transmitting function of the transmitting unit 11 and a receiving device having the receiving function of the receiving unit 12.

[0159] In addition, these programs can be distributed by storing them on storage media such as magnetic disks (floppy disks, hard disks, etc.), optical disks (CD-ROMs, DVDs, etc.), and semiconductor memories, and can also be transmitted and received via a network. [Explanation of symbols]

[0160] 1. Transmission and Reception System 2. Transmitting and receiving equipment 3 Wireless section 10 Interface section 11 Transmission unit (transmission device) 12 Receiving section (receiving device) 20 Pointer information addition section 21 Packet division section (fragment section) 22 Synchronization byte appending part 23 Error detection (correction) code addition unit 24 Modulation section 25,30 High frequency parts and antennas, etc. 31 Demodulation section 32 Error detection (correction) section 33 Synchronous byte analysis section 34 Pointer Information Analysis Unit 35 Packet combining section (defragmentation section)

Claims

1. A transmitting device which receives an IP packet and a video signal, generates an RS packet to which a synchronization byte is added from the IP packet and the video signal, modulates the RS packet by adding an error detection code capable of detecting an error or an error correction code capable of correcting an error, and transmits a modulated wave, a pointer information adding unit that receives the IP packet, deletes a preamble from the IP packet, generates pointer information including a payload length of the IP packet, and adds the pointer information to the IP packet from which the preamble has been deleted, thereby generating a packet including the pointer information and the payload of the IP packet; a packet division unit that divides the packet generated by the pointer information addition unit into pieces of a predetermined size to generate RS packet data; a synchronization byte addition unit that receives the RS packet data generated by the packet division unit and the video signal, generates the synchronization byte based on the RS packet data and the video signal, and adds the synchronization byte to each of the payloads of the RS packet data and the video signal to generate the RS packet, The synchronization byte adding unit A transmitting device characterized in that it generates a synchronization byte indicating information that identifies the RS packet data and the video signal, and in the case of the RS packet data, information that determines the position of the pointer information in the RS packet.

2. 2. The transmitting device according to claim 1, The synchronization byte adding unit When the video signal is input, the synchronization byte indicating that the video signal is input is generated; When the RS packet data including the pointer information is input, the pointer information is included in the RS packet, and the synchronization byte indicating the position of the pointer information is generated; When the RS packet data not including the pointer information is input, the transmitting device generates the synchronization byte indicating that the RS packet does not include the pointer information.

3. 3. The transmitting device according to claim 1, Further, a frame generating unit that generates a frame including a modulated signal of a predetermined number of the RS packets generated by the modulation, A transmitting device, characterized in that it transmits the modulated wave of the frame generated by the frame generating section.

4. A receiving device that receives a modulated wave of an RS packet to which a synchronization byte is added, decodes the RS packet by demodulation and error detection including error detection or correction, and restores an IP packet and a video signal from the RS packet, extracting the synchronization byte from the RS packet and extracting RS packet data excluding the synchronization byte from the RS packet; If the synchronization byte indicates information for identifying the video signal, recovering the video signal from the RS packet and outputting the video signal; a synchronization byte analysis unit that extracts the pointer information from the RS packet when the synchronization byte is information that identifies the RS packet and indicates information for determining a position of pointer information in the RS packet; a pointer information analysis unit that acquires a payload length of the IP packet from the pointer information extracted by the synchronization byte analysis unit; a packet combining unit that combines the RS packet data extracted by the synchronous byte analyzing unit according to the payload length of the IP packet acquired by the pointer information analyzing unit, deletes the pointer information from the combined RS packet data, and adds a preamble to generate the IP packet; A receiving device comprising:

5. 5. The receiving device according to claim 4, When the receiving device receives a modulated wave of a frame including a predetermined number of the RS packets, The receiving device further comprises a frame demodulation section that demodulates the frame from the received modulated wave signal and extracts the modulated signal of the predetermined number of the RS packets from the frame.

6. a computer constituting a transmitting device which receives an IP packet and a video signal, generates an RS packet to which a synchronization byte is added from the IP packet and the video signal, modulates the RS packet by adding an error detection code capable of detecting an error or an error correction code capable of correcting an error, and transmits a modulated wave; a pointer information adding unit that inputs the IP packet, deletes a preamble from the IP packet, generates pointer information including a payload length of the IP packet, and adds the pointer information to the IP packet from which the preamble has been deleted, thereby generating a packet including the pointer information and the payload of the IP packet; a packet division unit that divides the packet generated by the pointer information addition unit into pieces of a predetermined size to generate RS packet data; and a program for causing the program to function as a synchronization byte addition unit that inputs the RS packet data generated by the packet division unit and the video signal, generates the synchronization byte based on the RS packet data and the video signal, and adds the synchronization byte to each of the payloads of the RS packet data and the video signal, thereby generating the RS packet, The synchronization byte adding unit A program characterized by generating a synchronization byte indicating information for identifying the RS packet data and the video signal, and in the case of the RS packet data, information for determining the position of the pointer information in the RS packet.

7. A computer constituting a receiving device that receives a modulated wave of an RS packet to which a synchronization byte is added, decodes the RS packet by demodulation and error detection including error detection or correction, and restores an IP packet and a video signal from the RS packet. extracting the synchronization byte from the RS packet and extracting RS packet data excluding the synchronization byte from the RS packet; If the synchronization byte indicates information for identifying the video signal, recovering the video signal from the RS packet and outputting the video signal; a synchronization byte analysis unit that extracts the pointer information from the RS packet when the synchronization byte is information that identifies the RS packet and indicates information for determining a position of pointer information in the RS packet; a pointer information analysis unit that acquires a payload length of the IP packet from the pointer information extracted by the sync byte analysis unit; and A program for functioning as a packet combining unit that generates the IP packet by combining the RS packet data extracted by the synchronization byte analysis unit according to the payload length of the IP packet obtained by the pointer information analysis unit, deleting the pointer information from the combined RS packet data, and adding a preamble.

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