JPH09116890A - Bidirectional catv video data transmission control system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten video transmission time and to efficiently use a supply-side data accumulation device by convergently transmitting video data which a user designates through the use of multiple wavelengths. SOLUTION: Video data which a request-side processor 300 designates is divided into a prescribed quantity of packet data by a supply-side processor 100. Data are collectively transmitted to a request-side data accumulation device 302 by simultaneously using the plural wavelengths by a wavelength multiplex fiber 201 used as a communication line. The request-side processor 300 reorganizes and accumulates a transmitted packet and displays it on a display device screen 303 as video data.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a bidirectional CATV.
Related to the technical field of application.

[0002]

2. Description of the Related Art In the current bidirectional CATV system,
Using one wavelength for video transmission from the provider to the requester and one wavelength for video control from the requester to the provider,
Video data is continuously transmitted for a long time.

[0003] Viewing, such as reproduction, stop, pause, fast forward, and rewind, of the user's image is transmitted to the provider side processing device at the control wavelength, and the provider side processing device responds to the operation content. Control the video data and transmit the video data to the terminal side.

Although parallel data transmission between single devices is disclosed in Japanese Patent Laid-Open No. 6-89271, it is not for a plurality of terminals.

[0005]

DISCLOSURE OF THE INVENTION Present bidirectional CAT
The V system requires that the transmission line be continuously occupied while the user listens to the video. For this reason, the burden of communication cost on the user side is large due to the occupation of the communication line for a long time. Further, in order to simultaneously respond to the video viewing requests of many users, it is necessary to secure the transmission capacity according to the number of subscribers.

Further, in the current bidirectional CATV system, processing for video operations such as reproduction, stop, pause, fast forward, and rewind is executed by the processing apparatus on the provider side. Therefore, the providing side processing device has a large load because it is necessary to simultaneously execute processes for video operations such as reproduction, stop, pause, fast forward, and rewind from a plurality of terminals.

Further, on the provider side, it is necessary to hold all the data of the video image requested to be viewed on the memory until the user finishes watching the video image in order to deal with various video operations. Therefore, the provider side needs a large-capacity data storage device.

[0008] Further, the providing side needs to have a plurality of video data in order to meet various viewing requests of many users. Further, since video data particularly demanded for viewing (latest movie, etc.) is immediately started to be transmitted at the time of request, it is necessary to always hold it in the data storage device. Therefore, a large-capacity data storage device that stores a large amount of video data is required.

[0009]

In order to solve the above-mentioned problems, when video data is transmitted by a wavelength-multiplexed optical fiber, a method of collectively transmitting data to a video transmission request terminal side using a plurality of wavelengths is adopted. .

According to this method, when a video transmission request is made, all video data is transmitted from the provider side to the requesting terminal side, so that the user can perform video operations such as reproduction, stop, pause, fast forward, and rewind. Is to be executed by the terminal side processing device. Furthermore, by deleting the transmitted video data from the data storage device on the provider side, the utilization of the data storage device on the provider side is made efficient.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the equipment configuration of the present invention.

According to the present invention, a terminal device (300) for a user to watch a video, a provider device (100) for distributing requested video data to each terminal, and a video for each user terminal. It comprises a communication device (200) for relay transmission.

The terminal side device (300) is a terminal side processing device (301) for the user to perform various video operations, and a terminal side data storage device (30) for storing the transmitted video data.
2) and a terminal side display device (303) for displaying the video transmitted to the user. Each terminal device has a terminal identification ID that uniquely identifies each terminal device.

The providing side device (100) is a providing side processing device (10) for performing video operations and video transmission control from the terminal side.
1), a provider side data storage device (102) for storing various video data, and a communication device (103) for transmitting packetized video data to the terminal side.

The communication device comprises a wavelength division multiplexing optical fiber (201) used for packet transmission, and a branch relay device (202) for branch relay transmission of packets to each terminal.

Each processing in the terminal side device and the providing side device in the bidirectional CATV will be described below according to the device configuration shown in FIG.

First, after the system is activated, a transmission request for a viewable video list is transmitted from the terminal side processing device (301) to the providing side processing device (101) (step 10).
1).

The provider side processing device (101) receives the video list transmission request from the terminal side processing device (301) (step 102) and creates data of the viewable video list at the corresponding time (step 103). The viewable video list data includes the name of the viewable video and its video identification ID. Next, the providing side processing device (101) transmits the data of the viewable video list at the relevant time to the terminal side processing device (301) (step 104).

The terminal side processing device (301) receives the viewable video list data from the providing side processing device (101) (step 105) and displays the viewable video list data on the screen of the terminal side display device (303). Yes (Step 10
6).

The user selects a desired video from the viewable video list displayed on the screen (step 10).
7).

When the video is selected by the user, the terminal side processing unit (301) sends a corresponding video data transmission request to the providing side processing unit (101) (step 1).
08). The video data transmission request includes a terminal identification ID and a video identification ID.

When the provider side processing unit (101) receives the video data transmission request from the terminal side processing unit (301) (step 109), it confirms whether the requested video is on the data storage unit (102). (Step 110).

If not, the image requested by the terminal side processing unit (301) is stored in the data storage unit (102) as data that can be transmitted from a tape or the like (step 1).
11).

Next, the processing device (101) on the provider side packetizes the video data requested to be transmitted in units of a fixed amount (step 112).

A schematic structure of the packet is shown in FIG.

The content of each item of the packet is a header terminal identification ID that identifies the terminal that has issued a video transmission request to the processing device on the provider side.

When a packet is transmitted from the provider side to the terminal side, the destination terminal is identified.

Video identification ID for identifying the video requested to be viewed by the terminal side processing device.

Video Total Packet Count The total packet count when the video data requested to be viewed is packetized in fixed amounts.

Video packet No. An individual packet is identified when the video data requested to be viewed is packetized in a fixed amount.

Communication control data Other data used for communication control, etc. It consists of a check digit, etc.

Data part Video data, audio data, character data, etc.

Next, the providing side processing device (101) determines the number of transmission wavelengths to be assigned to each transmission requesting terminal. The calculation method of the number of allocated wavelengths is, for each transmission cycle, from the number of requesting viewing terminals at the time of request and the number of packets waiting to be transmitted for each terminal,
The method is to set the number of allocated transmission wavelengths for each terminal.

First, the processing device (101) on the providing side counts the number of video requesting terminals at that time (step 20).
1). Next, the processing device on the providing side (101) counts the number of packets waiting to be transmitted for each terminal at that time (step 202).

Next, the provider side processing device (101) sets the number of wavelengths for initial allocation by dividing the number of wavelengths for transmitting video data by the number of terminals requesting viewing at that time (step 20).
3).

Here, the number of wavelengths for transmitting video data means the number of wavelengths that can be used for transmitting video data to each terminal in the wavelength division multiplexing optical fiber (201).

Number of Wavelengths for Video Data Transmission / Number of Viewing Request Terminals at that Time = Number of Initially Assigned Wavelengths (However, Fractional Numbers are Rounded Down) Next, the provider side processing device (101) waits for transmission of each terminal to the number of initially assigned wavelengths If the number of packets is not sufficient and there are unused wavelengths, additional wavelength allocation is performed. The additional allocation calculation method is described below.

First, the provider processing device (101) compares the number of packets waiting for transmission for each terminal with the number of wavelengths of initial allocation (step 204).

(1) When the number of wavelengths of initial allocation <the number of packets waiting to be transmitted: The corresponding terminal is designated as an additional allocation requesting terminal (step 20).
4). The number of terminals in which the number of wavelengths of initial allocation is smaller than the number of packets waiting to be transmitted is counted (step 205) and is set as the number of terminals to which additional allocation is requested in the corresponding transmission cycle.

Number of additional allocation requesting terminals + 1 = Number of additional allocation requesting terminals (2) When number of initial allocation wavelengths = number of packets waiting to be transmitted The providing side processing device (101) sets the number of initial allocation wavelengths to the number of allocation wavelengths of the corresponding terminal. (Step 207).

(3) When Initially Assigned Wavelength Number> Transmission Waiting Packet Number The provider processing device (101) sets the transmission waiting packet number to the assigned wavelength number of the corresponding terminal (step 208). Next, the providing side processing device (101) calculates the number of unused wavelengths for each terminal (step 209) Number of initial assigned wavelengths-Number of packets waiting for transmission to each terminal =
Number of unused wavelengths for each terminal The providing side processing device (101) accumulates the number of unused wavelengths for each terminal and calculates the total number of unused wavelengths during the transmission cycle (step 207).

Total number of unused wavelengths + Number of unused wavelengths for each terminal = Total number of unused wavelengths The number of packets waiting to be transmitted and initial allocation to all terminals requesting transmission in the provider side processing device (101) After the number of wavelengths is compared (step 211), if the total number of unused wavelengths is 0 or more, additional allocation is performed. Provider side processing device (10
1) is the total number of unused wavelengths divided by the number of additional allocation request terminals,
The number of wavelengths to be additionally allocated to each additional allocation request terminal is set (step 212).

Total number of unused wavelengths / number of additional allocation requesting terminals = number of additional allocation wavelengths (however, rounded down) Next providing side processing device (101)
Sets the number of allocated wavelengths to the additional wavelength allocation requesting terminal by adding the number of additional allocated wavelengths to the number of initial allocated wavelengths (step 213).

Number of initial allocated wavelengths + number of additional allocated wavelengths = number of allocated wavelengths This sets the number of allocated wavelengths for each terminal in the transmission cycle.

An example of setting additional allocation of video transmission wavelengths to each terminal will be described below. It is assumed that the preconditions are set as follows.

Number of wavelengths for video transmission 1000 wavelengths Number of other transmission request terminals at the relevant time 3 Number of packets waiting to be transmitted for each terminal at the relevant time Terminal A 1000 packets Terminal B 500 packets Terminal C 2000 packets At this time, terminal D transmits video It is assumed that the request has been executed.
The number of packets of the request video of the terminal D is 1000. Further, it is assumed that a video transmission request is made from the terminal E to the terminal D during video transmission, and an example of additional allocation setting in each transmission cycle will be described below.

First Transmission Cycle The number of transmission requesting terminals at this point is 4, and the number of wavelengths initially allocated to each terminal is 1000/4 = 250. The number of unused wavelengths is 0, and there is no additional allocation to each terminal.

The number of wavelengths allocated to each terminal is terminal A 250 wavelength terminal B 250 wavelength terminal C 250 wavelength terminal D 250 wavelength.

Second transmission cycle The number of transmission requesting terminals at this point is 4, and the number of wavelengths initially allocated to each terminal is 1000/4 = 250. The number of unused wavelengths is 0, and there is no additional allocation to each terminal.

The number of wavelengths allocated to each terminal is terminal A 250 wavelength terminal B 250 wavelength terminal C 250 wavelength terminal D 250 wavelength.

Third Transmission Cycle At this point, the video transmission to the terminal B ends. Therefore, the number of transmission requesting terminals is three. The number of wavelengths initially assigned to each terminal is 1000/3 = 333 (however, fractional numbers are rounded down). The number of unused wavelengths is 0, and there is no additional allocation to each terminal.

The number of wavelengths assigned to each terminal is terminal A 333 wavelengths terminal C 333 wavelengths terminal D 333 wavelengths.

Fourth Transmission Cycle The number of transmission requesting terminals is 3, and the number of wavelengths initially allocated to each terminal is 1000/3 = 333. (However, rounded down)
At this time, the number of packets waiting to be transmitted by the terminals A and D is 1
67, and the number of unused wavelengths is 166. Since the number of additional allocation request terminals is 1, the total unused wavelength number 332 of the terminals A and D is additionally allocated to the terminal C.

The number of wavelengths allocated to each terminal is terminal A 167 wavelengths terminal C 665 wavelengths terminal D 167 wavelengths.

Fifth transmission cycle Transmission to terminals A and D is completed. Terminal E at this point
It is assumed that a video transmission request with 2000 video packets is generated. The number of transmission requesting terminals is 2, and the number of wavelengths initially allocated to each terminal is 1000/2 = 500. The number of unused wavelengths is 0, and there is no additional allocation to each terminal.

The number of wavelengths assigned to each terminal is terminal C 500 wavelength terminal E 500 wavelength.

Sixth Transmission Cycle The number of transmission requesting terminals is 2, and the number of wavelengths initially allocated to each terminal is 1000/2 = 500. At this time, the number of packets waiting to be transmitted by the terminal C is 2, and the number of unused wavelengths is 498. Since the number of additional allocation requesting terminals is 1, the number of unused wavelengths 498 of the terminal C is additionally allocated to the terminal E.

The number of wavelengths allocated to each terminal is terminal C 2 wavelength terminal E 998 wavelength.

At this point, the number of packets waiting to be transmitted by the terminal E becomes 502. Hereinafter, the transmission cycle is repeated until the video transmission is completed for all terminals.

Next, the provider communication device (103) prepares for packet transmission for each terminal in accordance with the number of allocated wavelengths set for each terminal (step 214), and sets the wavelength-multiplexed optical fiber (step 214). 201) and transmits to the transmission requesting terminal (300) through the relay branching device (202) (step 215).

The relay branching unit (202) relays the packet to the corresponding requesting terminal (300) based on the terminal identification ID of the packet (step 301).

The terminal side device (300) receives the packet of the video data transmitted from the providing side device (100) (step 302), and the terminal side data storage device (3).
02) is temporarily stored (step 303). When the transmission from the providing side device (100) is completed, reorganization is performed based on the video packet identification ID so that the video can be viewed (step 304), and a transmission check is performed (step 305). At this time, if there is a packet loss or data loss packet, the terminal side processing device (302)
Makes a request to retransmit the corresponding packet to the processing device (101) on the providing side (step 306). The resend request includes a terminal identification ID and a video packet No. (The packet loss check method and the data loss check method are not applicable.) When the provider side processing device (101) receives the retransmission request from the terminal side processing device (301) (step 307), there is a retransmission request. Data storage device (10
2) (step 308) and the terminal device (30)
0) is retransmitted (step 307). The transmission control method during retransmission is the same as during initial transmission.

The terminal side device (300) receives all the packets including the retransmission, performs the transmission check, and confirms the normal end of the transmission. After that, the terminal side processing device (301) provides the providing side processing device (301). 101), a reception completion message is transmitted (step 310). Next, the terminal side processing device (301) gives the user a terminal side display device (303).
A message notifying that the requested image can be viewed is displayed on the top (step 311). Various viewing operations (playback, stop, pause, fast forward, rewind, and other video operations) from the user can be controlled by the terminal processing device (301) (step 312).

After receiving the reception completion message from the terminal side processing device (301) (step 313), the providing side processing device (101) confirms a transmission request from another terminal for the video data (step 314). When there is a viewing request from another terminal for the video data, transmission processing is performed for the corresponding terminal (step 315). When there is no viewing request from the other terminal for the video data, the video data is erased from the provider side data storage device (103) (step 316). As a result, the data storage device on the provider side can be used for storing other video data.

[0065]

As described above, according to the present invention, the number of provider side data storage devices is reduced by shortening the video transmission time by using a large number of wavelengths for video data transmission at the same time and immediately erasing transmission end video data. It is expected that the operation of the video data on the requesting terminal side, the burden on the providing side processing device due to the processing can be reduced, and the congestion state at the providing side processing device due to simultaneous viewing requests from a plurality of terminals can be avoided.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram. It is a figure which shows the apparatus structure of the provision side apparatus, communication apparatus, and terminal side apparatus which implement | achieve this invention.

FIG. 2 is a packet configuration diagram. It is a figure which shows the packet structure content at the time of transmitting from a video data providing side to a terminal side.

FIG. 3 is a processing flow chart (1). Among the examples of the present invention,
It is a figure which shows the flow of a process to the packetization of the video data of the provision side with respect to the video transmission request from the terminal side.

FIG. 4 is a processing flowchart (2). Among the examples of the present invention,
It is a figure which shows the flow of a process of the allocation wavelength number setting for every terminal in a provision side apparatus.

FIG. 5 is a processing flowchart (3). Among the examples of the present invention,
It is a figure which shows the flow of the process which transmits video data from a provision side to a terminal side, and the process of the terminal side and the provision side after transmission.

[Explanation of symbols]

100 ... Providing side device, 101 ... Providing side processing device, 102 ... Providing side data storage device, 103 ... Providing side communication device, 200 ... Communication device, 201 ... Wavelength multiplexing optical fiber, 202 ... Relay branching device, 300 ... Terminal side apparatus,
301 ... Terminal-side processing device, 302 ... Terminal-side data storage device, 303 ... Terminal-side display device.

Claims (2)

[Claims] 1. In a bidirectional CATV (Video On Demand), a wavelength multiplexing optical fiber used as a communication line by dividing video data designated by a requesting processing device into a fixed amount of packet data by a providing processing device. At the same time, by using a plurality of wavelengths at the same time, they are collectively transmitted to the request side data storage device, the packets transmitted by the request side processing device are reorganized and accumulated, and displayed as video data on the display device screen. Transmission method. 2. The wavelength-division-type optical fiber used as a communication line in the video transmission system according to claim 1, depending on the number of terminals requesting video data viewing at the same time.
A method of increasing or decreasing the number of allocated wavelengths for data transmission per terminal. When the number of other viewing request terminals at the time of request is small, the number of allocated wavelengths is increased and video data transmission is performed in a short time.
A transmission control method in which the number of allocated wavelengths is reduced when the number of other viewing requesting terminals is large, and video data is repeatedly transmitted to each viewing requesting terminal.