JP6802731B2 - Transmitter and receiver - Google Patents

Description

The present invention relates to a transmitting device and a receiving device that time-division-multiplex a plurality of types of streams composed of packet strings carrying video signals, audio signals, or data signals on the transmitting side and transmit them via a transmission line of a passive network. ..

The transport stream used in current digital broadcasting is a fixed-length (188-byte) packet sequence starting with a synchronization byte of 0x47, such as an MPEG-2 TS (transport stream) packet, which forms a set of information. It is an eggplant.

Streams other than MPEG-2 TS include MMT (MPEG Media Transport) composed of packet strings of variable-length packets and TLV (Type Length Value). MPEG-2 TS packets (hereinafter referred to as "TS packets"), MMT packets (hereinafter referred to as "MMT packets"), and TLV packets (hereinafter referred to as "TLV packets") are used in digital broadcasting. Video coding is defined by the standards of the Association of Radio Industries and Businesses (ARIB) (for example, ARIB STD-B32).

On the other hand, as a method of rebroadcasting on a cable TV or a communication line, a method of transmitting by a radio frequency (RF) signal as in the case of broadcasting and an IP specified by the IPTV Forum (IPTV-F) (Internet Protocol) There is multicast broadcasting. The method of transmitting RF signals is specified in the standard of the Japan CATV Technology Association (for example, JCTEA STD-002-5.0). Further, IP multicast broadcasting is specified in the IPTV-F operation regulations (for example, IPTVFJ STD-0005).

In IP multicast broadcasting, a desired transmission stream is requested from the receiving side as an uplink signal, and only the stream to be viewed is mixed and transmitted as a downlink signal of communication. On the other hand, similar to broadcasting and cable television, a broadcasting type baseband transmission method in which all broadcasting streams are time-division-multiplexed and transmitted to a home is disclosed (see, for example, Non-Patent Document 1). In the broadcast-type baseband transmission system disclosed in Non-Patent Document 1, a wavelength dedicated to broadcasting is newly assigned separately from the wavelength for communication.

Hakamada et al., "Prototype of FTTH Digital Broadcasting Batch Distribution Device Using 10G Ethernet (Registered Trademark)", IEICE Technical Report CS, Communication Method, vol.114, no.119, CS2014-38, 2014, p. 127-130, published June 26, 2014

In the broadcast-type baseband transmission method disclosed in Non-Patent Document 1, a plurality of streams can be time-division-multiplexed and transmitted via a transmission line of a passive network, and a desired stream can be selected and output by a receiving device. .. In the transmission line of a passive network, unlike the existing RF signal, a switch is not interposed between transmission and reception (inter-station network / access network), so that unexpected transmission delay is inherently unlikely to occur.

For example, as shown in FIG. 7, the transmitting device 100 can time-division multiplex a plurality of streams and transmit them to the receiving device 200 via a transmission line of a passive network. FIG. 7 shows a case where the transmitting device 100 transmits the MMT stream and the MPEG-2 TS stream toward the receiving device 200.

The transmission device 100 shown in FIG. 7 includes transmission queues 101 and 102 and a time division multiplexing unit 103. The transmission device 100 converts the MMT packet into an Ethernet (registered trademark) frame for the MMT stream and stores it in the transmission queue 101, and converts the TS packet into an Ethernet (registered trademark) frame for the MPEG-2 TS stream. Store in the transmission queue 102.

The transmission frames of the Ethernet (registered trademark) frames stored in the transmission queue 101 and the transmission queue 102 are sequentially transmitted to the time division multiplexing unit 103 based on the cyclic parallel transmission control (round robin) method.

The time division multiplexing unit 103 time-divides and multiplex the transmission frames sequentially transmitted from the transmission queue 101 and the transmission queue 102, and transmits the transmission frames to the receiving device 200 via the transmission line of the passive network.

On the other hand, the receiving device 200 includes a separation / channel selection unit 210. For example, when an MMT stream is selected, the separation / channel selection unit 210 separates and extracts and outputs a transmission frame obtained by converting an MMT packet into an Ethernet (registered trademark) frame. .. As a result, the receiving device 200 can restore the selected MMT stream by a subsequent process (not shown).

However, in this broadcast-type baseband transmission method, as shown in FIG. 7, when time division multiplexing is performed by the transmission device 100, transmission delay fluctuation of the transmission frame occurs, and transmission delay fluctuation occurs in the stream output from the reception device 200 side. Occurs. As the number of transmission streams transmitted from the transmission device 100 increases, the transmission delay fluctuation of the stream output from the reception device 200 tends to increase.

Since an increase in the transmission delay fluctuation leads to a transmission frame loss, it is necessary to provide a buffer size sufficient for absorbing the transmission delay fluctuation on the receiving device 200 side, which leads to an increase in cost and a receiving device. In the subsequent processing (for example, playback processing) of 200, there arises a problem that the processing load such as video reproduction related to the selected stream is increased.

That is, in the conventional technique, when a stream composed of a variable length packet sequence such as an MMT packet or a TLV packet is multiplex-transmitted, the fairness of the amount of transmission delay fluctuation between the streams (that is, the fairness of the transmission service). Therefore, a technique for suppressing transmission delay fluctuations is desired.

In view of the above problems, the present invention ensures fairness in the amount of transmission delay fluctuation between streams, and a transmitter and a receiver that time-division multiplex a plurality of types of streams and transmit them via a transmission line of a passive network. Provide the device.

The transmission device of the present invention generates a reference time packet storing transmission reference time information periodically generated based on a clock in the own device, and at the same time, the transmission reference is set in a transmission frame in each of a plurality of types of streams to be transmitted. Time information is added, time-divided multiplex is performed together with the reference time packet, and the packet is transmitted to the receiving device via the transmission line of the passive network.

Further, the receiving device of the present invention secures synchronization between transmission and reception based on the transmission reference time information in the reference time packet obtained from the transmission device of the present invention, sets the clock, and sets the timing to output the selected stream. The transmission delay fluctuation is corrected by adjusting.

That is, the transmission device of the present invention is a transmission device that transmits a plurality of types of streams by time-division multiplexing via a transmission path of a passive network by a baseband transmission method, and is based on a clock in the transmission device. The transmission reference time information generating means for generating transmission reference time information indicating the transmission time at a predetermined cycle, and the transmission reference time information stored in the transmission frame constituting the stream, and stored in the transmission frame. A reference time packet generating means that generates transmission reference time information as a reference time packet, and transmission reference time information that adds the transmission reference time information to each transmission frame of the plurality of types of streams at the same time as the generation of the reference time packet. The additional means, the transmission frame of each of the plurality of types of streams to which the transmission reference time information is added, and the reference time packet are time-divided and multiplexed based on the cyclic parallel transmission control method, and the generated transmission signal is generated. It includes a time-division multiplexing / transmission control means for controlling a transmission signal, and a transmission line coding means for transmitting the transmission signal by applying a coding process to the transmission signal for transmission on the transmission line of the passive network. It is characterized by that.

Further, in the transmission device of the present invention, the time division multiplexing / transmission control means is based on the cyclic parallel transmission control method, and the reference time is more than the transmission frame in each of the plurality of types of streams to which the transmission reference time information is added. It is characterized by generating a transmission signal in which packets are time-division-multiplexed with the highest priority.

Further, the receiving device of the present invention is a receiving device that receives a plurality of types of streams by time division multiplexing via a transmission path of a passive network by a baseband transmission method, and is transmitted from the transmitting device of the present invention. The transmission path coding / decoding means that receives the transmission signal subjected to the coding process and performs a predetermined decoding process, and the clock of the receiving device are set based on the transmission reference time information in the reference time packet. A channel is selected from among a plurality of types of streams having transmission reference time information, a delay correction time generation means for generating delay correction time information obtained by adding a constant value to the time set in the clock, and a plurality of types of streams having the transmission reference time information. Based on the separation means for separating one or more streams and the delay correction time information, the timing of outputting the selected one or more streams to the outside is adjusted, and the transmission frame in each of the plurality of types of streams is adjusted. It is characterized by comprising a transmission delay fluctuation correction means for correcting a predetermined transmission delay fluctuation caused by time-division multiplexing.

Further, in the receiving device of the present invention, the delay correction time generating means generates the delay correction time by setting a value equal to or more than a predetermined maximum delay fluctuation amount assumed in advance as the constant value and adding it to the time set by the clock. It is characterized by doing.

Further, in the receiving device of the present invention, the transmission delay fluctuation correcting means includes a transmission reference time information removing means that removes the transmission reference time information from one or more selected streams and outputs the externally. And.

According to the present invention, for a plurality of types of streams transmitted by the broadcast-type baseband transmission method, the transmission delay fluctuation of the stream output from the receiving device is corrected, and the fairness of the transmission delay fluctuation amount between the streams is ensured. be able to.

It is a block diagram which shows the schematic structure of the transmission system of the broadcast type baseband transmission system which comprises the transmission device and the reception device of one Embodiment by this invention. It is a block diagram which shows the schematic structure of the transmission device of one Embodiment by this invention. It is a block diagram which shows the schematic structure of the receiving device of one Embodiment by this invention. It is a figure which shows the operation of one Example of the transmission device of one Embodiment by this invention. It is a figure which shows the operation of one Example of the receiving device of one Embodiment by this invention. It is a figure which shows the calculated value of the maximum delay fluctuation amount in the transmission system of the broadcasting type baseband transmission system which comprises the transmission device and the receiving device of one Embodiment by this invention. It is a block diagram which shows the schematic structure of the transmission system of the broadcasting type baseband transmission system of the prior art.

Hereinafter, the transmitting device 10 and the receiving device 20 according to the embodiment of the present invention will be described with reference to the drawings.

(Transmission system)
First, FIG. 1 shows a schematic configuration of a broadcast-type baseband transmission system transmission system including a transmission device 10 and a reception device 20 according to the embodiment of the present invention. In the broadcast-type baseband transmission system shown in FIG. 1, a plurality of types (n types) of streams D1 to Dn are time-divided and multiplexed from the transmission device 10 and transmitted to the reception device 20 via the transmission line of the passive network. , The receiving device 20 is configured to separate each stream D1 to Dn. In the broadcast-type baseband transmission method shown in FIG. 1, a wavelength dedicated to broadcasting is newly assigned separately from the wavelength for communication. Further, the transmitting device 10 and the receiving device 20 are similar to the existing RF signal, and are not limited to, but are limited to a plurality of types of streams D1 to Dn via a transmission path of a passive network such as PON (Passive Optical Network). Is time-division-multiplexed and transmitted, so that a switch does not intervene between transmission and reception (inter-station network / access network).

(Transmitter)
FIG. 2 is a block diagram showing a schematic configuration of a transmission device 10 according to an embodiment of the present invention. The transmission device 10 includes a clock source 11, a transmission reference time information generation unit 12, an encapsulation unit 13, a reference time packet generation unit 14, a cyclic parallel transmission control unit 15, a time division multiplexing unit 16, and the like. A transmission line coding unit 17 is provided.

The clock source 11 generates a clock in the transmission device 10 and constantly outputs the clock to the transmission reference time information generation unit 12.

The transmission reference time information generation unit 12 includes a clock counter that inputs and counts the clock from the clock source 11, periodically generates time information on the transmission side based on the clock from the clock source 11, and transmits the clock. The time information on the side is output as transmission reference time information to the encapsulation unit 13 and the reference time packet generation unit 14.

The encapsulation unit 13 includes transmission reference time information addition units 131-1 to 131-n for each of a plurality of types (n types) of streams D1 to Dn.

Each of the transmission reference time information addition units 131-1 to 131-n inputs each of the corresponding plurality of types (n types) of streams D1 to Dn, and transmits a transmission frame having a predetermined length via the transmission line of the passive network. As soon as the transmission reference time information periodically generated by the transmission reference time information generation unit 12 is input, it is added to the transmission frame and output to the cyclic parallel transmission control unit 15.

Here, as a method of adding transmission reference time information to the transmission frame, for example, in the case of a TS packet, the TS packet group is encapsulated in an Ethernet (registered trademark) frame as this transmission frame and transmitted to the first TS packet. There are a method of forming a TTS (Time-stamped Transport Stream) packet to which reference time information is added, and a method of describing the transmission reference time information in a free area in the header information of the transmission frame. Other streams such as MMT and TLV can be configured in the same manner. That is, the method of adding the transmission reference time information to the transmission frame can be any method as long as it is known between the transmission device 10 and the reception device 20.

The reference time packet generation unit 14 generates a transmission frame storing the transmission reference time information as a reference time packet as soon as the transmission reference time information periodically generated by the transmission reference time information generation unit 12 is input, and cyclically. Output to the parallel transmission control unit 15.

The encapsulation unit 13 allocates channel selection identification information such as an IP address and a VLAN tag associated with an ID for identifying each stream (for example, a stream ID) for each stream D1 to Dn of each transmission frame. Describe in the header. Similarly, the reference time packet generation unit 14 assigns fixed channel selection identification information to the reference time packet and describes it in the header of the transmission frame.

The cyclic parallel transmission control unit 15 inputs and stores transmission frames corresponding to each of a plurality of types (n types) of streams D1 to Dn from the encapsulation unit 13, and each transmission queue 151-1 to 151-n. , A transmission queue 152 for inputting and storing a transmission frame configured as a reference time packet from the reference time packet generation unit 14, and each transmission frame stored in the transmission queues 151-1 to 151-n and the transmission queue 152. , Based on the cyclic parallel transmission control (round robin) method, the files are sequentially transmitted to the time division multiplexing unit 103.

Here, the reference time packet is generated at regular intervals, but the cyclic parallel transmission control unit 15 sets the reference time packet at the maximum rather than the transmission frame in each of the plurality of types of streams to which the transmission reference time information is added. It is sent to the time division multiplexing unit 16 so as to perform time division multiplexing based on the cyclic parallel transmission control method with priority. Therefore, the cyclic parallel transmission control unit 15 constantly monitors whether or not the transmission frame configured as the reference time packet is stored (enqueued) in the transmission queue 152, and immediately when it is stored, the time division multiplexing unit 16 Control to output to.

The time division multiplexing unit 16 time division multiplexes the transmission frame input from the cyclic parallel transmission control unit 15 and outputs the transmission frame to the transmission line coding unit 17. As described above, the time division multiplexing unit 16 multiplexes the reference time packet based on the cyclic parallel transmission control method with the highest priority over the transmission frame in each of the plurality of types of streams, and the transmission line coding unit 17 Output to.

The transmission line coding unit 17 performs transmission line coding processing such as error correction coding processing on the time division multiplexing transmission signal output from the time division multiplexing unit 16, and receives the receiver via the transmission line of the passive network. Transmit to 20. As the transmission line coding process, for example, 10GE-PON coding (IEEE 802.3av) standardized by IEEE can be used.

(Receiver)
FIG. 3 shows a schematic configuration of the receiving device 20 according to the embodiment of the present invention. The receiving device 20 includes a transmission line coding / decoding unit 21, a separation unit 22, a clock reproduction unit 23, a reference time packet extraction unit 24, a clock 25, a delay correction time generation unit 26, and a delay amount setting unit 27. And a transmission delay fluctuation correction unit 28.

The transmission line coding / decoding unit 21 receives the transmission signal from the transmission device 10, performs decoding processing corresponding to the transmission line coding process of the transmission line coding unit 17 in the transmission device 10, and outputs the decoding process to the separation unit 22. ..

The separation unit 22 separates a desired channel-selected stream from the transmission signal after the decoding process by the transmission path coding / decoding unit 21 based on the stream channel selection signal set from the outside, and outputs it to the transmission delay fluctuation correction unit 28. At the same time, when the transmission signal after the decoding process by the transmission path coding / decoding unit 21 contains a reference time packet, the reference time packet extraction unit 24 extracts the reference time packet.

The stream channel selection signal is a signal based on channel selection identification information that identifies each stream desired by the operator of the receiving device 20.

As the stream channel selection signal, one or a plurality of streams D1 to Dn of a plurality of types (n types) transmitted from the transmission device 10 can be selected, and in FIG. 3, the plurality of types (n types) of the streams are selected. An example in which all of streams D1 to Dn are selected is shown. Therefore, when the receiving device 20 is configured to separate all of the plurality of types (n types) of streams D1 to Dn in advance and output them as targets for transmission delay fluctuation correction, the stream tuning signal is not necessarily separated from the separation unit 22. It is not necessary to input to.

In addition, each transmission frame of the plurality of types (n types) of streams D1 to Dn output from the separation unit 22 may include transmission reference time information (for example, time A), and therefore, the separation unit 22 From 22, a plurality of types (n types) of streams D1 to Dn with transmission reference time information (for example, time A) are separately output.

The clock reproduction unit 23 reproduces the clock from the output signal from the transmission line coding / decoding unit 21 and outputs the clock to the clock 25.

The reference time packet extraction unit 24 uniquely assigns to the separation unit 22 whether or not the transmission signal after the decoding process by the transmission line coding / decoding unit 21 includes the reference time packet. It is constantly monitored based on the information, and if a reference time packet is included, it is extracted and output to the clock 25.

The clock 25 includes a clock counter that inputs and counts the clock reproduced by the clock reproduction unit 23, thereby performing clock synchronization matching the transmission side, and as soon as the reference time packet is input from the reference time packet extraction unit 24, the reference time is used. The time is set based on the transmission reference time information (for example, time A) included in the time packet, the output control unit 281 is time-synchronized, and the time of the transmission reference time information (for example, time A) for which the time is set is set as the delay correction time. Notify the generation unit 26.

The delay correction time generation unit 26 adds the time of the transmission reference time information (for example, time A) to the time obtained by adding a constant value (a value equal to or greater than the previously assumed maximum delay fluctuation amount) set by the delay amount setting unit 27. The indicated delay correction time information (for example, time B) is generated and output to the transmission delay fluctuation correction unit 28.

The delay amount setting unit 27 sets a constant value (a value equal to or greater than the maximum delay fluctuation amount assumed in advance) in the delay correction time generation unit 26.

The transmission delay fluctuation correction unit 28 includes an output control unit 281 and an output buffer 282-1.282-n.

The output control unit 281 operates in time synchronization by the clock 25, inputs delay correction time information (for example, time B) from the delay correction time generation unit 26, and inputs each of a plurality of types (n types) of streams D1 to Dn. By monitoring the added transmission reference time information, each time of a plurality of types (n types) of streams D1 to Dn having transmission reference time information (for example, time A) becomes delay correction time information (for example, time B). The output of each output buffer 282-1.282-n that temporarily holds each of a plurality of types (n types) of streams D1 to Dn is controlled so as to output to the outside when the time is reached.

Each of the output buffers 282-1.282-n is a buffer that temporarily holds each of a plurality of types (n types) of streams D1 to Dn, and each includes a transmission reference time information removing unit 282a. The transmission reference time information removing unit 282a is a functional unit that removes the transmission reference time information (for example, time A) added to the stream and outputs it to the outside. In the case of the receiving device 20 in which the separation unit 22 selects only one of a plurality of types (n types) of streams D1 to Dn, the output buffer 282-n can be set to one.

(Example)
Hereinafter, more specifically, with reference to FIGS. 4 to 6, the transmitting device 10 and the receiving device 20 of the embodiment according to the present invention are based on the transmitting device 10a and the receiving device 20a of the corresponding embodiment, respectively. , Each operation will be described in detail.

FIG. 4 is a diagram showing the operation of the transmission device 10a of one embodiment. The transmission device 10a is configured to time-division multiplex the MPEG-2 TS stream and the MMT stream for transmission, and as described with reference to FIG. 2, the clock source 11, the transmission reference time information generation unit 12, It includes an encapsulation unit 13, a reference time packet generation unit 14, a cyclic parallel transmission control unit 15, a time division multiplexing unit 16, and a transmission path coding unit 17.

The transmission reference time information generation unit 12 counts by the clock counter 12a based on the clock from the clock source 11 of the transmission device 10a to generate transmission reference time information at regular intervals, and the encapsulation unit 13 and the reference time packet generation unit 12 generate the transmission reference time information. Output to 14.

The encapsulation unit 13 performs transmission frames of the MPEG-2 TS stream and the MMT stream (for example, encapsulation by an Ethernet (registered trademark) frame), and adds transmission reference time information generated at a fixed cycle.

For example, the encapsulation unit 13 is in a transmission frame that encapsulates a TS packet group of an MPEG-2 TS stream and transmits the transmission reference time information generated at a fixed cycle as soon as it is input. It is added to the first TS packet to make an MPEG-2 TTS packet. Similarly for MMT (or TLV as well), the encapsulation unit 13 encapsulates one MMT packet into a transmission frame (for example, encapsulation by an Ethernet (registered trademark) frame), and a transmission reference generated at a fixed cycle. As soon as the time information is input, it is added to the beginning of the transmission frame to be transmitted at the time of input.

Further, the transmission reference time information generated at the fixed cycle is stored in the reference time packet generated by the reference time packet generation unit 14.

In order to time-division-multiplex the MPEG-2 TS, MMT, and reference time packets by the time-division multiplexing unit 16, the cyclic parallel transmission control unit 15 uses each transmission frame of the MPEG-2 TS, MMT, and reference time packets. When sending to the time division multiplexing unit 103 in order based on the cyclic parallel transmission control (round robin) method for the transmission queues 151-1 and 151-2 and the transmission queue 152, respectively, the transmission queue is used. Queuing (dequeue) is performed with the highest priority given to the reference time packet stored in 152.

Subsequently, each transmission frame time-divided and multiplexed by the time-division multiplexing unit 16 is subjected to transmission coding processing by the transmission line coding unit 17, and the transmission signal is transmitted to the receiving device 20 via the transmission line of the passive network. Is transmitted to.

FIG. 5 is a diagram showing the operation of the receiving device 20a of one embodiment. The receiving device 20a is configured to receive a transmission signal obtained by time-dividing and multiplexing a MPEG-2 TS stream and an MMT stream, separate them so as to be selectable, correct the transmission delay fluctuation of the desired stream, and output the signal. As described with reference to FIG. 3, the transmission line coding / decoding unit 21, the separation unit 22, the clock reproduction unit 23, the reference time packet extraction unit 24, the clock 25, the delay correction time generation unit 26, and the delay amount setting unit 27. , And a transmission delay fluctuation correction unit 28.

The transmission signal decoded by the transmission line coding decoding unit 21 is input to the separation unit 22.

The separation unit 22 is a stream selected from the transmission signal after the decoding process by the transmission line coding / decoding unit 21 based on the stream channel selection signal set from the outside (in this example, the stream of MPEG-2 TS). The MMT stream) is separated and output to the transmission delay fluctuation correction unit 28.

Here, when the transmission signal after the decoding process by the transmission line coding / decoding unit 21 contains the reference time packet, the reference time packet extraction unit 24 separates the reference time packet from the separation unit 22 and extracts the reference time packet. Then, it is output to the clock 25.

The clock 25 performs clock synchronization that matches the transmission side by a clock counter 23a that inputs and counts the clock reproduced by the clock reproduction unit 23.

Then, as soon as the reference time packet is input from the reference time packet extraction unit 24, the clock 25 sets the time based on the transmission reference time information (for example, time A) included in the reference time packet, and sets the time in the transmission delay fluctuation correction unit 28. The output control unit 281 synchronizes the time, and the delay correction time generation unit 26 is notified of the time of the transmission reference time information (for example, time A) for which the time is set.

The delay correction time generation unit 26 adds the time of the transmission reference time information (for example, time A) to the time obtained by adding a constant value (a value equal to or greater than the previously assumed maximum delay fluctuation amount) set by the delay amount setting unit 27. The indicated delay correction time information (for example, time B) is generated and output to the transmission delay fluctuation correction unit 28.

Here, FIG. 6 shows a calculated value of the maximum delay fluctuation amount in the transmission system of the present embodiment (when the frame length of the transmission frame is 1522 bytes). The maximum delay fluctuation amount (μsec) shown in FIG. 6 is calculated by the equation (1).

Equation (1) is an equation for calculating the maximum delay fluctuation amount of the jth stream when n streams are multiplexed by the round robin method assuming a transmission system using 10G Ethernet (registered trademark). L _k indicates the frame length (bytes) of the transmission frame of the kth stream. In addition, _LIFG indicates the interframe gap (IFG) length indicating the interval from one transmission frame to the next transmission frame.

As can be seen from FIG. 6, the maximum delay fluctuation amount (μsec) and the number of transmission streams are in a substantially proportional relationship, and by prescribing the maximum number of streams transmitted by the transmission system of the present embodiment, the delay amount A value set by the setting unit 27 that is equal to or greater than the maximum delay fluctuation amount shown in FIG. 6 can be treated as a constant value.

The transmission delay fluctuation correction unit 28 operates in time synchronization by the clock 25, inputs delay correction time information (for example, time B) from the delay correction time generation unit 26, and has transmission reference time information (for example, time A). When the MPEG-2 TS and MMT are monitored to be output from the separation unit 22 and the delay correction time information (for example, time B) is reached, the transmission reference time information (for example, time A) added to the stream is reached. ) Is removed and output to the outside.

As described above, according to the transmission device 10 and the reception device 20 according to the present invention, a plurality of types of streams are time-division-multiplexed to transmit in a passive network while ensuring fairness in the amount of transmission delay fluctuation between streams. It can be transmitted via a road.

In particular, when a stream composed of a variable length packet sequence such as an MMT packet or a TLV packet is time-division-multiplexed and transmitted, an increase in transmission delay fluctuation can be suppressed.

As a result, on the receiving device 20 side, it is possible to reduce the burden of processing that requires time adjustment in the subsequent processing (for example, reproduction processing) and the reduction of the buffer size.

In the above-described embodiment examples, Ethernet (registered trademark) type encapsulation and 10G Ethernet (registered trademark) passive network have been mainly described as examples, but the present invention is limited to the above-described embodiment examples. It is not limited by the description of the scope of claims.

According to the present invention, the fairness of the amount of transmission delay fluctuation between streams can be ensured, and a plurality of types of streams can be time-divided and multiplexed and transmitted via a transmission line of a passive network. It is useful for transmission system applications.

10 Transmission device 11 Clock source 12 Transmission reference time information generation unit 13 Encapsulation unit 14 Reference time packet generation unit 15 Circular parallel transmission control unit 16 Time division multiplexing unit 17 Transmission line coding unit 20 Reception device 21 Transmission line coding Decoding unit 22 Separation unit 23 Clock playback unit 24 Reference time packet extraction unit 25 Clock 26 Delay correction time generation unit 27 Delay amount setting unit 28 Transmission delay fluctuation correction unit 100 Transmission device 101, 102 Transmission queue 103 Time division multiplexing unit 131- 1,131-n Transmission reference time information addition unit 151-1,151-2,151-n, 152 Transmission queue 200 Receiver 210 Separation / channel selection unit 281 Output control unit 282-1282-2 Output buffer 282a Transmission reference Time information removal unit

Claims (5)

A transmission device that uses a baseband transmission method to time-division multiplex and transmit multiple types of streams via the transmission line of a passive network.
A transmission reference time information generating means that generates transmission reference time information indicating a transmission time at a predetermined cycle based on the clock in the transmission device, and
A reference time packet generation means that stores the transmission reference time information in a transmission frame constituting the stream and generates the transmission reference time information stored in the transmission frame as a reference time packet.
A transmission reference time information adding means that adds the transmission reference time information to each transmission frame of the plurality of types of streams at the same time as the generation of the reference time packet.
A transmission signal in which each transmission frame of a plurality of types of streams to which the transmission reference time information is added and the reference time packet are time-division-multiplexed based on a cyclic parallel transmission control method is generated, and the generated transmission signal is controlled. Time division multiplexing / transmission control means
A transmission line coding means for transmitting the transmission signal by subjecting the transmission signal to a coding process for transmission on the transmission line of the passive network.
A transmitter characterized by comprising. Based on the cyclic parallel transmission control method, the time-division multiplexing / transmission control means time-division-multiplexes the reference time packet with the highest priority over the transmission frame in each of the plurality of types of streams to which the transmission reference time information is added. The transmission device according to claim 1, wherein a transmission signal is generated. It is a receiving device that receives multiple types of streams by time division multiplexing via the transmission line of a passive network by the baseband transmission method.
A transmission line coding / decoding means that receives the coded transmission signal transmitted from the transmission device according to claim 1 or 2 and performs a predetermined decoding process.
A clock setting means for setting the clock of the receiving device based on the transmission reference time information in the reference time packet, and
A delay correction time generation means for generating delay correction time information obtained by adding a constant value to the time set in the clock, and
A separation means for separating one or more selected streams from a plurality of types of streams having transmission reference time information, and
A predetermined transmission delay caused by time-division multiplexing of transmission frames in each of the plurality of types of streams by adjusting the timing of outputting one or more selected streams to the outside based on the delay correction time information. Transmission delay that corrects fluctuations Fluctuation correction means and
A receiving device characterized by comprising. 3. The delay correction time generation means is characterized in that a value equal to or more than a predetermined maximum delay fluctuation amount assumed in advance is set as the constant value and added to the time set by the clock to generate the delay correction time. The receiver described in. The transmission delay fluctuation correction means is provided with the transmission reference time information removing means for removing the transmission reference time information from one or more selected streams and outputting the transmission reference time information to the outside, according to claim 3 or 4. The receiver described.