JP2914148B2 - Signal path selection device and program transmission system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal path selecting device used in a communication system for transmitting signals in a frequency division multiplex system, and a program transmission system in which one transmission path is constituted by a plurality of signal sources. .

[0002]

2. Description of the Related Art FIG. 33 shows a conventional example of a communication system for performing signal transmission by a frequency division multiplex system such as a CATV network. In FIG. 33, 3301, 3302, 3303,
Reference numerals 3304, 3305, and 3306 denote node 1, node 2, node 3, node 4, node 5, and node 6 for mixing and amplifying signals, respectively. Also, 3307, 3
308, 3309, and 3310 are terminal 1, terminal 2, terminal 3, and terminal 4, respectively. 3311 is a center.

In general, a CATV network uses a coaxial cable as a transmission line, and divides a transmission frequency of the coaxial cable into a “high band” and a “low band”, and respectively divides the transmission frequency into a “down band” and an “up band”. A single communication path is formed by combining one carrier wave belonging to both bands, and has a bidirectional function.

[0004] Hereinafter, in the present invention, the upstream part (communication from the terminal to the center) of one communication path is called an uplink channel, and the downstream part (communication from the center to the terminal) is called a downlink channel. Further, when simply referred to as a channel, both are included.

[0005] The transmission path of the CATV network is constituted by a dendritic network as shown in FIG. 33, and each terminal partially shares the transmission path. For this reason, if the same channel is assigned to all transmission paths, signal collision occurs at the node. To avoid this, a method of assigning a unique channel to the transmission path to which the terminal belongs is often used.

[0006] In these communication paths, mutual frequency conversion between an "up channel" and a "down channel" is performed at a center by a device called a head end.

When communication is performed between a center and a terminal, (1) a method in which channels are allocated to all terminals in advance (2) the center sequentially polls the terminals and communicates with terminals having a call request. Allowed method (3) A method in which a terminal makes a call request to the center through a common control line and the center permits or designates a line to be used. There are methods such as a method for setting communication independently on the terminal.

[0008] Also, in communication between arbitrary terminals, access to the center is performed in the same manner as in communication between the center and the terminal.

[0009]

However, each of the above-described conventional configurations and methods has problems. This will be described below.

[0010] When communication is performed between the center and the terminal or when communication is performed between arbitrary terminals, the four main methods are known as described above. 1) In the method of allocating channels to all terminals in advance, when the number of terminals exceeds the number of channels that can be handled, it becomes necessary to allocate overlapping channels to the terminals, and collisions at nodes cannot be avoided. .

(2) In the method in which the center polls the terminals sequentially and permits communication to the terminal requesting the call, when the number of terminals increases, the terminal requests the call and permits from the center. The average waiting time until you get it becomes very long.

(3) In a method in which a terminal makes a call request to a center through a common control line and the center permits or designates a line to be used, the number of channels available in the entire network can be effectively used. It is impossible to: An example is described with reference to FIG.

First, the terminal 3 (3309) is connected to the terminal 2 (33
08) A call request is issued to the center through the common control line in order to perform communication to 08). Then, the center is channel 1,
The communication using the channel 2 is permitted, and the terminal 3 (330
When the terminal 9 (3) is communicating with the terminal 2 (3308), the communication from the terminal 1 (3307) to the terminal 4 (3310) cannot be performed at the same time using the channels 1 and 2.

The terminal 3 (3309) and the terminal 2 (330
The fact that 8) uses channel 1 and channel 2 is nothing but the use of channel 1 and channel 2 of the entire network. This is because the function of the node is only to mix and amplify the frequency division multiplexed signal. Therefore, this method is not perfect in terms of effective use of the frequency band.

(4) In the method in which the terminal constantly monitors the use status of the line and independently sets the communication when the line is free, when the number of terminals increases, signal collision easily occurs and the efficiency is improved. Communication cannot be performed.

(5) In a conventional head end, a signal is returned by converting a signal received through an upstream channel into a downstream channel according to a fixed conversion rule. When the signal received by the upstream channel is looped back to the downstream channel and the downstream channel is in use,
Even if another downlink channel is vacant, it cannot return to the vacant channel. This is because it does not have a function of frequency-converting a signal of an arbitrary uplink channel to an arbitrary downlink channel, so that the channel cannot be used effectively. And the like.

As described above, in any of the methods, since the functions of the node and the head end are not sufficient, the channel cannot be effectively used. A similar problem also exists in a program transmission system in which one transmission path is configured from a plurality of signal sources.

[0018]

According to a first aspect of the present invention, there is provided a divider for distributing a frequency division multiplexed signal to a plurality of systems of frequency division multiplexed signals, and a plurality of systems of frequency division multiplexed signals. An uplink frequency converter for converting an arbitrary frequency in a signal to another frequency and mixing the same into one system of frequency division multiplexed signal; and a node controller for controlling the uplink frequency converter based on a control signal. Configuration.

The second means of the present invention is a divider for distributing a frequency division multiplexed signal to a plurality of systems of frequency division multiplexed signals, and converting an arbitrary frequency in the plurality of frequency division multiplexed signals to another frequency. An upstream frequency converter for mixing into a system of frequency division multiplexed signals, and a return direction frequency converter for converting an arbitrary frequency in a plurality of frequency division multiplexed signals to another frequency and distributing the same to a plurality of systems of frequency division multiplexed signals And a mixer for mixing a plurality of frequency division multiplexed signals, and a node control unit for controlling the uplink frequency selection unit and the return frequency conversion unit based on a control signal. .

The third means of the present invention comprises: a down frequency converter for converting an arbitrary frequency in the frequency division multiplexed signal to another frequency and distributing the frequency to a plurality of systems of frequency division multiplexed signals;
A divider for distributing a frequency division multiplexed signal to a plurality of systems of frequency division multiplexed signals, and an uplink frequency converter for converting an arbitrary frequency in the frequency division multiplexed signal to another frequency and mixing it into one system of frequency division multiplexed signals And, a folding direction frequency conversion unit that converts an arbitrary frequency in the frequency division multiplexed signal to another frequency and distributes the frequency division multiplexed signal to a plurality of systems, and a mixer that mixes the plurality of systems of the frequency division multiplexed signal, It has a configuration including a node control unit that controls the uplink frequency conversion unit, the return frequency conversion unit, and the downlink frequency conversion unit based on a control signal.

The fourth means of the present invention comprises: a downlink frequency converter for converting an arbitrary frequency in a downlink data signal, which is a frequency division multiplexed signal, to another frequency and outputting it; Control means for dynamically controlling the frequency of the downlink frequency conversion section based on the frequency.

Further, the program transmission system of the present invention provides a management table including a name of a program transmitted on a transmission path, a frequency on which the program is multiplexed, a signal source of the program, and a management table including a terminal connected to the transmission path. A frequency management device that requests output of a program to a transmission path based on a program reception request; and a signal path selection device that frequency-converts a plurality of frequency division multiplexed signal sources based on a program output request from the frequency management device. It is a thing.

[0023]

According to this configuration, (1) in the case of communication between terminals, it is not always necessary to communicate with the center via the head end, and by filtering the signal at an appropriate node, the channel of the entire network can be controlled. Make effective use.

(2) The node and the head end have a frequency conversion function, and the above problem is solved.
In addition, make effective use of channels.

(3) The center manages the channels collectively and performs the optimal scheduling of the channels, so that the center optimally controls the filtering unit and the frequency conversion unit in the node and the head end. Etc. become possible.

Also, it becomes possible to dynamically frequency-division multiplex programs from a plurality of signal sources within a limited frequency band.

[0027]

【Example】

(Embodiment 1) This embodiment relates to a communication system in which the signal path selection device of the present invention is applied to a conventional CATV network. Hereinafter, the signal path selection device of the present invention is applied to a conventional node, and is described as a “node device”. The uplink data signal or the downlink data signal is a frequency division multiplex signal.

Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 2 is a block diagram showing the configuration of the first embodiment of the present invention. Uplink data signal 204
a, the downlink data signal 204b, the uplink control signal 208a, and the downlink control signal 208b are one set, and these signals are connected to another downlink node device or terminal device.

Similarly, the four signals of the uplink data signal 205a, the downlink data signal 205b, the uplink control signal 209a, and the downlink control signal 209b are connected to another downlink node device or terminal device.

The four signals of the uplink data signal 207a, the downlink data signal 207b, the uplink control signal 210a, and the downlink control signal 210b are connected to the node device or headend in the uplink direction.

Reference numeral 201 denotes an uplink frequency converter. The uplink frequency conversion unit 201 outputs the uplink data signal 204a
And an uplink data signal 205a as input, convert an arbitrary frequency in those signals to another frequency, mix them, and output as an uplink data signal 207a. The uplink frequency converter 201 has a structure as shown in FIG. FIG. 3 will be described later.

Reference numeral 202 denotes a downstream distributor. Downlink distributor 202 receives downlink data signal 207b as input,
The signal is distributed and output as a downlink data signal 204b and a downlink data signal 205b. 203 is a node control unit. The node control unit 203 performs the following operation.

(1) When the uplink control signal 208a or the uplink control signal 209a is not a control signal to be processed, the control signal is transmitted as an uplink control signal 210a to a node device or a head end in the uplink direction. If the signal is a control signal to be processed, a signal for controlling the uplink frequency converter 201 is generated based on the control signal, and sent to the uplink frequency converter 201.

(2) If the downlink control signal 210b is not a control signal to be processed, the signal is
8b or a downlink control signal 209b is sent to a node device or a terminal device in the downlink direction. If it is a control signal to be processed, a signal for controlling the uplink frequency converter 201 is generated based on the control signal,
This is sent to uplink frequency converter 201.

Referring to FIG. 3, uplink frequency converter 201
Will be described. 301a and 301b are distributors which receive an input 305a and an input 305b, respectively, and distribute and output them. A mixer 302 mixes a plurality of input signals and outputs the mixed signal as an output 306.

304a (1), 304a (2), 3
04a (n) and 304b (1), 304b
(2),..., 304b (n) are frequency converters, which can convert a channel in an arbitrary frequency band to a channel in another frequency band. Reference numeral 308 denotes a frequency converter control signal, and the frequency converters 304a (1) and 304a
(2), 304a (n) and 304b (1),
The frequency to be converted by each of 304b (2), 304b (n) is controlled. Each frequency converter controls which frequency is selected as an input and which frequency is selected as an output by a frequency converter control signal 308.

303a (1), 303a (2), 3
03a (n) and 303b (1), 303b
(2),..., 303b (n) are switches (SW), and these switches determine whether or not the signal output from the frequency converter is sent to the mixer 302. Reference numeral 307 denotes a SW control signal, and SW 303a (1), 303a
(2), 303a (n) and 303b (1),
On / off of each of 303b (2), 303b (n) is controlled. When the SW is turned on by the SW control signal, the signal output from the frequency converter
2, the signal output from the frequency converter is not sent to the mixer 302 when the SW is turned off. The SW control signal 307 and the frequency converter control signal 308 are control signals sent from the node control unit 203.

The input 305a is connected to the upstream data signal 20.
4a, the input 305b corresponds to the uplink data signal 205a, and the output 306 corresponds to the uplink data signal 207a.

Next, an example of a communication system using the node device of this embodiment is shown in FIG. 4, and its operation will be described in detail. Reference numeral 402 denotes a signal path determination unit, which determines paths for all communication performed in the communication system shown in FIG. FIG. 5 shows the structure of the signal path determination unit 402. FIG. 5 will be described later.

Reference numeral 401 denotes a head end, which is basically used in a conventional CATV network. However, it is different in that it has a function of transmitting an uplink control signal input from a node device to the signal path determination unit 402 and then transmitting a control signal from the signal path determination unit as a downlink control signal to each node device in the downlink direction. . 403 and 404 are node devices. 405, 406, 407, 408 are terminal devices. Terminal devices 405, 406, 407, 408
Has a function of performing modulation on one uplink channel and demodulation from one downlink channel, and further has a function of transmitting one uplink control signal to a node device in the uplink direction and a function of transmitting one downlink control signal in the uplink direction. It has the function of receiving from the control unit of

Also, the head end is one of the upstream channels.
Simple frequency conversion is performed such that a channel is converted into one downlink channel and two uplink channels are converted into two downlink channels.

Node device A 403 and head end 401
Are the uplink data signal 413a and the downlink data signal 413
b, uplink control signal 419a, and downlink control signal 419b.

Similarly, the node device B 404 and the head end 401 communicate with the uplink data signal 414a, downlink data signal 414b, uplink control signal 420a, downlink control signal 420
b.

Node device A 403 and terminal device A 405
Are the uplink data signal 409a and the downlink data signal 409
b, uplink control signal 415a, and downlink control signal 415b.

The other node devices and the terminal device are similarly connected by four signals.

The node device A 403 and the node device B 40
4. The input / output system on the left side of the head end 401 will be described as a down direction A, and the input / output system on the right side will be described as a down direction B below.

The signal path determining section will be described with reference to FIG. Reference numeral 501 denotes a signal path determination unit. Reference numeral 504 denotes a management table, which stores information for determining a signal path in a terminal device information management table, a communication information management table, and a node device information management table. An optimization unit 503 receives information for determining a signal path as input and determines an optimal path based on the input. Optimizer 5
03, "Iwanami Course Software Science Algorithms and Data Structures", Iwanami Shoten, Kiyoshi Ishihata, p. 260 to p. 276 can be reduced to the shortest path problem.

If each node device, head end, and each terminal device are considered as nodes of the graph theory, determining the communication path between the terminal devices is considered to be equivalent to obtaining the shortest path between the nodes. . A path control unit 502 controls the optimization unit 503 and the management table 504, and exchanges signals with the headend. The route control unit 502 extracts information necessary for determining a route from the management table 504 based on the control signal received from the head end, and sends the information to the optimization unit 503. Next, control information of the signal path determined by the optimization unit 503 is obtained, and the information is recorded in the management table 504. Finally, the control information of the signal path is sent to the head end.

FIG. 6 is a diagram showing the contents of the management table 504. Reference numeral 601 denotes a terminal device information management table, in which (1) terminal name: terminal name (2) uplink channel: channel that the terminal can modulate (3) downlink channel: channel that the terminal can demodulate (4) connection Destination node name: Contains four items: the name of the node device to which the terminal is connected.

Reference numeral 602 denotes a communication information management table, in which (1) communication number: a number uniquely assigned to each communication (2) source terminal name: name of the source terminal (3) Destination terminal name: Name of destination terminal (4) Attributes: Attributes required for communication Attributes include analog (communication using only analog signals) and digital (use only digital signals). Communication), and composite (communicate by combining analog and digital signals). The above four items are included.

Reference numeral 603 denotes a node device information management table. The table includes: (1) node name: node name (2) uplink (output) [1] channel information • channel: channel output in the uplink Number-Status: Indicates the status of the channel.

The states include busy, unused, and communication disabled. -Communication number: Same as the item of communication number in communication information management table 602-Attribute: Same as the item of attribute in communication information management table 602 [2] Connection destination: Name of connection destination (3) Upward direction (input) [1] ] Channel information Channel: Channel number input from the upstream direction The other sub-items are the same as in the upstream direction (output).

(4) Downward direction A (output) [1] Channel information • Channel: channel number output in downward direction A Other small items are the same as in the upward direction (output).

(5) Downstream direction A (input) [1] Channel information Channel: channel number input from downstream direction A Other sub-items are the same as in the upward direction (output).

(6) Downward direction B (output) [1] Channel information Channel: channel number output in the downward direction B The other minor items are the same as in the upward direction (output).

(7) Downward direction B (input) [1] Channel information Channel: channel number input from the downward direction B The other minor items are the same as in the upward direction (output).

The following seven items are included. FIG. 7 shows the format of the control signal. The control signals include signals transmitted and received between a terminal device and a node device, a terminal device and a head end, a head end and a node device, a node device and a node device, a terminal device and a terminal device, and the like. These control signals are realized in two formats.

(1) Communication request data format Used when the terminal device sends a communication request.

-Destination: destination to send communication request-Source terminal name: Source terminal name-Destination terminal name: Destination terminal name-Attribute: Same as attribute item in communication information management table 602 (2) Node control data format When the headend sends a control signal to the node device or the terminal device, when the node device sends a control signal to the node device or the terminal device, the terminal device sends the control signal to the terminal device or the node device. Use when sending.

Destination: destination for sending node control data Input system: [1] When the destination is a node device Up direction (input), down direction A (input), down direction B
(Input).

[2] When the destination is a terminal device Meaningless ・ Input channel: [1] When the destination is a node device Which channel is selected from the channels input to those specified by the above input system. Is specified.

[2] When the destination is a terminal device It is determined which channel is to be selected from the downlink channels.

Output system: [1] When destination is node device: Up direction (output), down direction A (output), down direction B
(Output).

[2] When the destination is a terminal device Meaningless • Output channel: [1] When the destination is a node device Which channel is selected from the channels output from those specified in the above output system Is specified.

[2] When the destination is the terminal device It is determined which channel is to be selected from the upstream channels.

FIGS. 8, 9, and 10 show examples of the initial state of the management table of the communication system of FIG.

Reference numeral 801 denotes a terminal management information management table. In the case of the terminal device A405, the “terminal name” is “terminal device A”, the “uplink channel” is “1”, the “downlink channel” is “1”, and the “connection destination node name” is “node device A”. Therefore, the terminal device A 405 transmits the uplink channel 1
And has a function of demodulating from the downlink channel 1 and is connected to the node device A 403. The same applies to the following.

Reference numeral 802 denotes a communication information management table.
Since no communication is performed in the initial state, the communication information management table 802 does not hold information.

Reference numeral 901 denotes a node device information management table for the node device A 403. Regarding the uplink (output) system, the “channel” of the channel information is “1,
2, 3, 4 "," status "is all" unused "," communication number "is blank, and" attribute "is all" analog ". "Connection" is "Headend"
It is. Therefore, the node device A403 can output 1, 2, or 3 channels in the uplink (output) system.
There are three and four channels, each of which communicates by analog, and since it is an initial state, the state is unused and the communication number is blank. The upstream (input) system is the same as the upstream (output) system.

Regarding the downlink A (input) system, the “channel” of the channel information is “1”, the “state” is “unused”, the “communication number” is blank, and the “attribute” Is "analog". The “connection destination” is “terminal device A”. Therefore, the node device A403
With respect to the downstream (input) system, the channel that can be input is channel 1, and channel 1 is performing analog communication, and since it is an initial state, the state is unused and the communication number is blank.

The downstream A (output) system, the downstream B (input) system, and the downstream B (output) system are the same as the downstream A (input) system. 1001 is a node device B40
4 is a node device management table for No. 4. The contents are the same as those of the node device information management table 901.

In the communication system shown in FIG. 4, how communication is actually performed is described with reference to FIGS.
This will be specifically described with reference to FIGS. 13, 14, 15, and 16.

First, the terminal device A 405 and the terminal device C 4
The case of performing communication with 07 will be described. Communication is performed in the following procedure.

(1) The terminal device A creates communication request data according to the communication request data format. The communication request data is the communication request data 110 in FIG.
It looks like 1. The communication request data 1101 is transmitted from the terminal device A 405 and the terminal device C 4 to the head end 401.
07 means that a request is made to set a communication path using only analog signals.

(2) The communication request data 1101 is transmitted as an uplink control signal 415a. Then the node device A40
3 and becomes an uplink control signal 419 a, and finally the communication request data 1101 arrives at the head end 401.

(3) The head end 401 sends the communication request data 1101 that has arrived to the signal path determining unit 402.

(4) The signal path determination unit 402 determines an optimal communication path by the optimization unit 503 based on the communication request data 1101 and the management table 504. The contents of the management table 504 after the determination of the communication path include the communication information management table 1102, the node device information management table 1201,
It looks like the node device information management table 1301.

In the communication information management table 1102, “communication number” is “1”, “source terminal name” is “terminal device A”, “destination terminal name” is “terminal device C”, and “attribute” is “attribute”. Communication between the terminal device A and the terminal device C is recorded as "analog".

The node device information management table 1201
The difference from the node device information management table 901 in the initial state is as follows: Regarding the upstream (output) system, the “status” of the channel 1 item of the channel information is “in use” and the “communication number” is “1”. Has become.

Regarding the downlink A (input) system, the “status” of the channel 1 item of the channel information is “in use” and the “communication number” is “1”.

That is to say. Node device A403
Will use each channel of the above system.

The node device information management table 1301
The difference from the node device information management table 1001 in the initial state is as follows: Regarding the upstream (input) system, the “state” of the channel 1 item of the channel information is “in use” and the “communication number” is “1”. Has become.

Regarding the downlink A (output) system, the “state” of the channel 1 item of the channel information is “in use” and the “communication number” is “1”. That is to say. The node device B404 uses the respective channels of the above system.

As described above, the signal path determined by the signal path determining unit 402 is as follows.

[1] The terminal device A 405 uses the uplink channel 1 and outputs it as an uplink data signal 409a.
The output is the down direction A (input) of the node device A403.
Input to the system channel 1 (uplink data signal 40
9a).

[2] The node device A 403
Channel 1 of the (input) system is output as channel 1 of the uplink (output) system. Its output is headend 4
01 to the upstream channel 1 (upstream data signal 413a). [3] The head end 401 loops the uplink channel 1 back to the downlink channel 1. The output becomes the input to the channel 1 of the upstream (input) system of the node device B404 (downlink data signal 41
4b).

[4] The node device B404 outputs the channel 1 of the upstream (input) system as the channel 1 of the downstream A (output) system. The output is input to the downlink channel 1 of the terminal device C 407 (downlink data signal 412b). [5] Terminal device C4
07 receives data from the downlink channel 1.

Data from the terminal device A 405 is transmitted to the terminal device C 407 along the above route.

(5) In order to set the above-mentioned route, the signal route determining unit 402 sets the node control data 1103
Create

Next, the node control data 1103 will be described. The node control data sent to the node device A 403 includes “destination” of “node device A”, “input system” of “downstream A”, “input channel” of “1”, and “output system” of “uplink”. The “direction” and “output channel” are “1”. With this node control data, the node device A 403
Directly outputs the channel 1 of the downstream A (input) system to the channel 1 of the upstream (output) system.

The node control data sent to the node device B 404 is the same as that of the node device A 403.

(6) Finally, node control data 1103
Is transmitted to each node device, thereby completing the route setting.

Next, a description will be given of a case where communication between terminal device B 406 and terminal device D 408 is performed following communication between terminal device A 405 and terminal device C 407. Communication is performed in the following procedure.

(1) The terminal device B creates communication request data according to the communication request data format. The communication request data corresponds to the communication request data 140 in FIG.
It looks like 1. The communication request data 1401 is transmitted from the terminal device B 406 and the terminal device D 4 to the head end 401.
08 indicates that a request is made to set a communication path using only analog signals.

(2) The communication request data 1401 is transmitted as the uplink control signal 416a. Then the node device A40
3 and becomes an uplink control signal 419 a, and finally the communication request data 1401 arrives at the head end 401.

(3) The head end 401 sends the communication request data 1401 that has arrived to the signal path determining unit 402.

(4) The signal path determination unit 402 determines an optimum communication path by the optimization unit 503 based on the communication request data 1401 and the management table 504. The contents of the management table 504 after the determination of the communication path include the communication information management table 1402, the node device information management table 1501,
It becomes like the node device information management table 1601.

In the communication information management table 1402, “communication number” is “2”, “source terminal name” is “terminal device B”, “destination terminal name” is “terminal device D”, and “attribute” is “attribute”. Communication between the terminal device B and the terminal device D is added as “analog”.

The node device information management table 1501
The difference from the node device information management table 1201 is as follows: Regarding the upstream (output) system, the “status” of the channel 2 item of the channel information is “in use” and the “communication number” is “2”. .

Regarding the downlink B (input) system, the “status” of the channel 1 item of the channel information is “in use” and the “communication number” is “2”.

That is to say. Node device A403
Will use each channel of the above system.

The node device information management table 1601
The points different from the node device information management table 1301 in the initial state are as follows: Regarding the uplink (input) system, the “status” of the channel 2 item of the channel information is “in use” and the “communication number” is “2”. Has become.

Regarding the downlink B (output) system, the “status” of the channel 2 item of the channel information is “in use” and the “communication number” is “2”.

That is to say. Node device B404
Will use the respective channels of the above system.

As described above, the signal path determined by the signal path determining unit 402 is as follows.

[1] Terminal apparatus B 406 uses uplink channel 1 and outputs it as uplink data signal 410a.
The output is the down direction B (input) of the node device A403.
Input to the channel 1 of the system (uplink data signal 41
0a).

[2] The node device A 403
Channel 1 of the (input) system is output as channel 2 of the upstream (output) system. Here, the node device A 403
Performs frequency conversion in the up direction. The output is
The data is input to the upstream channel 2 of the head end 401 (upstream data signal 413a).

[3] The head end 401 loops the upstream channel 2 back to the downstream channel 2. The output becomes an input to the channel 2 of the upstream (input) system of the node device B404 (the upstream data signal 414).
b).

[4] The node device B404 outputs the channel 2 of the upstream (input) system as the channel 2 of the downstream B (output) system. The output is the terminal device D4
08 is input to the downlink channel 2 (uplink data signal 412b).

[5] The terminal device D408 receives data from the downlink channel 2. Data from the terminal device B 406 is transmitted to the terminal device D 408 along the above route.

(5) In order to set a path as described above, the signal path determining unit 402
Create

Next, the node control data 1403 will be described. The node control data sent to the node device A 403 includes “destination” of “node device A”, “input system” of “downstream B”, “input channel” of “1”, and “output system” of “upstream”. The “direction” and “output channel” are “2”. With this node control data, the node device A 403
Converts the frequency of the channel 1 of the downstream A (input) system and outputs it to the channel 2 of the upstream (output) system.

The node control data sent to node device B 404 is the same as that of node device A 403.

(6) Finally, the node control data 1403
Is transmitted to each node device, thereby completing the route setting.

In the conventional CATV network, it was impossible to realize the above two communications at the same time. That is, by performing communication between the terminal device A 405 and the terminal device C 407, the upstream channel 1 and the downstream channel 1 of the entire network are used, so that the communication between the terminal device B 406 and the terminal device D 408 cannot be performed. is there. By using the node device of the present invention instead of the conventional node,
Since uplink frequency conversion is possible, it is possible to simultaneously implement the above two communications. By performing communication between the terminal device A 405 and the terminal device C 407, the uplink channel 1 is used over the entire network. However, when performing communication between the terminal device B 406 and the terminal device D 408, the node device A 403 converts the frequency of the uplink channel 1 output from the terminal device B 406 to the uplink channel 2 so that the terminal device B 406 and the terminal device D 408 communicate with each other. D4
08 communication becomes possible. As described above, according to the present embodiment, more effective use of the channel becomes possible.

Further, in this embodiment, only one-way communication has been described, but two-way communication is also possible. For example, after the communication between the terminal device A 405 and the terminal device C 407 is established, the communication between the terminal device C 407 and the terminal device A 405 may be established.

Further, in this embodiment, the case where the terminal device can transmit and receive only one channel has been described. However, the present invention can easily cope with a terminal device which can transmit and receive a plurality of channels. For example, a modulation / demodulation circuit in the terminal device may be controlled by a downlink control signal connected to the terminal device.

Although the present embodiment has been described with reference to the case where there are two inputs to the node device, the present invention can easily cope with a case where there are more inputs. For example, what can be realized by extending the contents of the management table can be easily analogized.

Further, in this embodiment, even if the number of physical transmission lines for transmitting the four signals of the uplink data signal, the downlink data signal, the uplink control signal, and the downlink control signal is one, a plurality of physical transmission lines are required. It can easily be inferred that it is adaptable.
It can be easily analogized that the control signal can be transmitted and received using a public line.

(Embodiment 2) The present embodiment relates to a communication system in which the signal path selection device of the present invention is applied to a conventional CATV network. Hereinafter, the signal path selection device of the present invention is applied to a conventional node, and is described as a “node device”. The uplink data signal or the downlink data signal is a frequency division multiplex signal.

Hereinafter, a second embodiment of the present invention will be described with reference to the drawings. FIG. 17 is a block diagram showing the configuration of the second embodiment of the present invention. Uplink data signal 17
07a, downlink data signal 1707b, and uplink control signal 17
11a and a downlink control signal 1711b are one set, and these signals are connected to another downlink node device or terminal device.

Similarly, the four signals of the uplink data signal 1708a, the downlink data signal 1708b, the uplink control signal 1712a, and the downlink control signal 1712b are connected to another downlink node device or terminal device. Further, four of the uplink data signal 1709a, the downlink data signal 1709b, the uplink control signal 1710a, and the downlink control signal 1710b.
The two signals are connected to an upstream node device or headend.

Reference numeral 1704a denotes an upstream distributor. The uplink distributor 1704a receives the uplink data signal 1707a, distributes the signal, and outputs the uplink data signal 1713a.
a and the uplink data signal 1713b.

Reference numeral 1704b denotes an upstream distributor. The uplink distributor 1704b is the same as the uplink distributor 1704a.

Reference numeral 1701 denotes an uplink frequency converter.
The uplink frequency converter 1701 outputs the uplink data signal 17
13a and the uplink data signal 1714a are input, and any frequency in those signals is converted to another frequency, mixed, and output as an uplink data signal 1709a. The uplink frequency converter 1701 has a structure as shown in FIG. 3 of the first embodiment. Also, the uplink data signal 1713a
Is input 305a and upstream data signal 1714a is input 3
At 05b, the uplink data signal 1709a corresponds to the output 306, respectively.

Reference numeral 1702 denotes a return direction frequency conversion unit. The return direction frequency conversion unit 1702 receives the uplink data signal 1713b and the uplink data signal 1714b, converts an arbitrary frequency in those signals to another frequency, mixes the signals, and outputs the downlink data signal 1715a and the downlink data signal 1715b. Output as The folding direction frequency conversion unit has a structure as shown in FIG. FIG. 18 will be described later. Reference numeral 1703 denotes a downstream distributor. The downlink distributor 1703 outputs the downlink data signal 1
709b is input, the signal is distributed, and output as a downlink data signal 1716a and a downlink data signal 1716b.

Reference numerals 1705a and 1705b denote downstream mixers. The downlink mixer 1705a receives the downlink data signal 1715a and the downlink data signal 1716a, mixes the signals, and outputs the resulting signal as a downlink signal 1707b.

Reference numeral 1706 denotes a node control unit. The node control unit 1706 performs the following operation.

(1) When the uplink control signal 1711a or the uplink control signal 1712a is not a control signal to be processed, the control signal is set as the uplink control signal 1710a.
It is transmitted to the node device or the head end in the upstream direction. If it is a control signal to be processed, a signal for controlling the uplink frequency conversion section 1701 and the return frequency conversion section 1702 is generated based on the control signal and sent to each section.

(2) When the downlink control signal 1710b is not a control signal to be processed, the signal is
711b or a downlink control signal 1712b is sent to a node device or a terminal device in the downlink direction. If it is a control signal to be processed, a signal for controlling the uplink frequency conversion section 1701 and the return frequency conversion section 1702 is generated based on the control signal and sent to each section.

A description will be given of the folding direction frequency conversion unit 1702 with reference to FIG. 1801a and 1801
b is a distributor, which has inputs 1805a and 18
05b as input, distributes and outputs them. 180
Reference numerals 2a and 1802b denote mixers which mix input signals of a plurality of systems and output signals 1806a and 1806b, respectively.
Output as

1804a (1), 1804a
(2), 1804a (n) and 1804b
(1), 1804b (2),..., 1804b (n) are frequency converters, which can convert any one channel to another channel. Reference numeral 1808 denotes a frequency converter control signal, and the frequency converters 1804a (1) and 1804a
(2), 1804a (n) and 1804b
(1), 1804b (2), and 1804b (n) control the frequency to be converted. Which frequency converter selects which frequency as input,
Which frequency is selected as an output is controlled by a frequency converter control signal 1808. 1803a
(1), 1803a (2), 1803a (n) and 1803b (1), 1803b (2), 180
Reference numeral 3b (n) denotes switches (SW), which switch the signals output from the frequency converter by the mixers 1802
a or the mixer 1802b. 18
07 is a SW control signal, and SW1803a (1), 1
803a (2), 1803a (n) and 180
3b (1), 1803b (2), 1803b (n)
Is controlled on / off. When the SW is turned on by the SW control signal, the signal output from the frequency converter is sent to the mixer 1802a or 1802b, and when the SW is turned off, the signal output from the frequency converter is output. Mixer 1802a or mixer 1802
b will not be sent. The SW control signal 1807 and the frequency converter control signal 1808 are transmitted to the node control unit 17
06 is a control signal sent from the control unit.

The input 1805a is the upstream data signal 1
713b, input 1805b is an uplink data signal 1714
b, the output 1806a becomes the downlink data signal 1715b,
Outputs 1802b correspond to downlink data signals 1715a, respectively.

An example of a communication system using the node device of the present embodiment is the same as FIGS. 4, 5, 6, and 7 of the first embodiment. The initial state of the management table of the communication system according to the present embodiment is the same as in FIGS. 8, 9, 10, and 11.

The case where communication is performed between terminal device A 405 and terminal device B 406 will be described. Communication is performed in the following procedure.

(1) The terminal device A creates communication request data according to the communication request data format. The communication request data is the communication request data 190 in FIG.
It looks like 1. The communication request data 1901 is transmitted from the terminal device A 405 and the terminal device B 4 to the head end 401.
06 means that a request is made to set a communication path using only analog signals.

(2) The communication request data 1901 is transmitted as the uplink control signal 415a. Then the node device A40
3 and becomes an uplink control signal 419 a, and finally the communication request data 1901 arrives at the head end 401.

(3) The head end 401 sends the arriving communication request data 1901 to the signal path determining unit 402.

(4) The signal path determination unit 402 determines an optimum communication path by the optimization unit 503 based on the communication request data 1901 and the management table 504. The contents of the management table 504 after the determination of the communication path are as shown in the communication information management table 1902 and the node device information management table 2001.

In the communication information management table 1902, the “communication number” is “1”, the “source terminal name” is “terminal device A”, the “destination terminal name” is “terminal device B”, and the “attribute” is Communication between the terminal device A and the terminal device B is recorded as "analog".

The node device information management table 2001 shown in FIG.
The differences from 01 are as follows: Regarding the downlink A (input) system, the “status” of the channel 1 item of the channel information is “in use” and the “communication number” is “1”.

Regarding the downlink B (output) system, the “status” of the channel 2 item of the channel information is “in use”.
In addition, the “communication number” is “1”.

That is to say. Node device A403
Will use each channel of the above system. The contents of the node device information management table for the node device B 404 are not changed from the initial state.

As described above, the signal path determined by the signal path determining unit 402 is as follows.

[1] Terminal apparatus A 405 outputs transmission data as uplink data signal 409 a using uplink channel 1. The output becomes an input to the channel 1 of the downlink A (input) system of the node device A403 (uplink data signal 409a).

[2] The node device A 403
Channel 1 of the (input) system is output as channel 2 of the downstream B (output) system. Here, the node device A40
Numeral 3 performs frequency conversion and performs a return process from the upward direction to the downward direction. The output is input to the downlink channel 2 (downlink data signal 410b).

[3] The terminal device B 406 receives data from the downlink channel 2. Data from the terminal device A 405 is transmitted to the terminal device B 406 along the above route.

(5) In order to set the above-mentioned route, the signal route determining unit 402 sets the node control data 1903
Create

The node control data 1903 will be described. The node control data sent to the node device A 403 is such that “destination” is “node device A”, “input system” is “downstream A”, “input channel” is “1”, and “output system” is “downstream”. The “direction B” and the “output channel” are “2”. With this node control data, the node device A 403
Converts the frequency of the channel 1 of the downstream A (input) system, performs a loopback process, and outputs the result to the channel 2 of the downstream B (output) system.

(6) Finally, the node control data 1903
Is transmitted to the node device A 403 to complete the route setting.

In the conventional CATV network, it was impossible to realize the above communication. Conventionally, terminal device A4
Also, when communication is performed between the terminal device B 405 and the terminal device B 406, the data signal output from the terminal device A 405 is transmitted to the head end once, and then returned at the head end, where
Sent to 406.

On the other hand, in the present embodiment, since the node device can perform the signal return processing, the terminal device A 40
It is not necessary to send the data signal from 5 to the head end. Therefore, the channel between the node device and the head end is not used, and the channel can be effectively used.

Further, in this embodiment, only one-way communication has been described, but two-way communication is also possible. For example, after the communication between the terminal device A 405 and the terminal device B 406 is established, the communication between the terminal device B 406 and the terminal device A 405 may be established.

In the present embodiment, the case where the terminal device can transmit and receive only one channel has been described. However, the present invention can easily cope with a terminal device which can transmit and receive a plurality of channels. For example, a modulation / demodulation circuit in the terminal device may be controlled by a downlink control signal connected to the terminal device.

Further, in the present embodiment, the case where there are two inputs to the node device has been described, but it is possible to easily cope with a case where there are more inputs. For example, what can be realized by extending the contents of the management table can be easily analogized.

In this embodiment, even if the number of physical transmission lines for transmitting the four signals of the uplink data signal, the downlink data signal, the uplink control signal, and the downlink control signal is one, a plurality of physical transmission lines are required. It can easily be inferred that it is adaptable.
It can be easily analogized that the control signal can be transmitted and received using a public line.

(Embodiment 3) This embodiment is for a communication system in which the signal path selection device of the present invention is applied to a conventional CATV network. Hereinafter, the case where the signal path selection device of the present invention is applied to a conventional node is referred to as a “node device”, and the case where the signal path selection device of the present invention is applied to a conventional head-end device is referred to as a “route device”. Describe. The uplink data signal or the downlink data signal is a frequency division multiplex signal.

Hereinafter, a third embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the third embodiment of the present invention. Uplink data signal 107
a, the downlink data signal 107b, the uplink control signal 111a, and the downlink control signal 111b are one set, and these signals are connected to another downlink node device or terminal device. Similarly, the uplink data signal 108a, the downlink data signal 108b, and the uplink control signal 11
The four signals 2a and the downlink control signal 112b are connected to another downlink node device or terminal device. Further, the uplink data signal 109a and the downlink data signal 109b
The four signals of the uplink control signal 110a and the downlink control signal 110b are connected to the node device or the route device in the uplink direction.

Reference numeral 104a denotes an upstream distributor. The uplink distributor 104a receives the uplink data signal 107a, distributes the signal, and outputs the uplink data signal 113a and the uplink data signal 113b.

Reference numeral 104b denotes an upstream distributor. The uplink distributor 104b is the same as the uplink distributor 104a.

Reference numeral 101 denotes an uplink frequency converter. The uplink frequency converter 101 outputs the uplink data signal 113a
And an upstream data signal 114a as input, convert an arbitrary frequency in those signals to another frequency, mix them, and output as an upstream data signal 109a. The uplink frequency converter 101 has a structure as shown in FIG. 3 of the first embodiment. The upstream data signal 113a is input to the input 305a.
The upstream data signal 114a corresponds to the input 305b, and the upstream data signal 109a corresponds to the output 306.

Reference numeral 102 denotes a return direction frequency conversion unit. The return direction frequency converter 102 receives the uplink data signal 113b and the uplink data signal 114b as input, converts an arbitrary frequency in those signals to another frequency, mixes them, and outputs the downlink data signal 115a and the downlink data signal 1b.
Output as 15b. The folding direction frequency conversion unit
The structure is as shown in FIG. 18 of the second embodiment. The upstream data signal 113b is input to the input 1805a, the upstream data signal 114b is input to the input 1805b, the downstream data signal 115a is output to the output 1806b, and the downstream data signal 115b is output.
b corresponds to each output 1806a.

Reference numeral 105a denotes a downstream mixer. Downlink mixer 105a receives downlink data signal 115a and downlink data signal 116a, mixes the signals, and outputs the result as downlink signal 107b.

Reference numeral 105b denotes a downstream mixer. The downstream mixer 105b is the same as the downstream distributor 105a.

Reference numeral 103 denotes a downlink frequency converter. The downlink frequency converter 103 outputs the downlink data signal 109b
Is input, and an arbitrary frequency in the signal is converted to another frequency, distributed, and output as a downlink data signal 116a and a downlink data signal 116b. The downlink frequency converter 103 has a structure as shown in FIG. FIG.
1 will be described later.

Reference numeral 106 denotes a node control unit. The node control unit 106 performs the following operation.

(1) When the uplink control signal 111a or the uplink control signal 112a is not a control signal to be processed, the control signal is transmitted as an uplink control signal 110a to a node device or a route device in the uplink direction. If it is a control signal to be processed, a signal for controlling the uplink frequency conversion unit 101, the return frequency conversion unit 102, and the downlink frequency conversion unit 103 is generated based on the control signal. send.

(2) If the downlink control signal 110b is not a control signal to be processed, the signal is
1b or a downlink control signal 112b is sent to a node device or a terminal device in the downlink direction. If it is a control signal to be processed, the uplink frequency converter 101 and the return frequency converter 10
2 and a signal for controlling the downlink frequency conversion unit 103 are generated and sent to each unit.

Referring to FIG. 21, downlink frequency converting section 10
3 will be described. Reference numeral 2101 denotes a distributor, and an input 2
105 is input, distributed and output. 210
Reference numerals 2a and 2102b denote mixers which mix input signals of a plurality of systems and output 2106a and output 2106, respectively.
Output as 106b.

2104a (1), 2104a
(2), 2104a (n) and 2104b
(1), 2104b (2), 2104b (n) are frequency converters, which can convert any one frequency to another frequency. Reference numeral 2108 denotes a frequency converter control signal, and the frequency converters 2104a (1) and 2104a
(2), 2104a (n) and 2104b
(1) The frequency to be converted by each of 2104b (2), 2104b (n) is controlled. Which frequency converter selects which frequency as input,
Which frequency is selected as the output is controlled by the frequency converter control signal 2108.

2103a (1), 2103a
(2), 2103a (n) and 2103b
(1), 2103b (2), and 2103b (n) are switches (SW), and the switches output the signals output from the frequency converter to the mixers 2102a and 212.
02b. Reference numeral 2107 denotes a SW control signal, and SW 2103a (1), 2103a
(2), 2103a (n) and 2103b
(1) Control ON / OFF of each of 2103b (2) and 2103b (n). S by SW control signal
When W is turned on, the signal output from the frequency converter is sent to the mixer 2102a or 2102b, and when SW is turned off, the signal output from the frequency converter is transmitted to the mixer 2102a. Or to the mixer 2102b. The SW control signal 2107 and the frequency converter control signal 2108 are control signals sent from the node control unit 106.

The input 2105 is the downlink data signal 10
9b, the output 2106a becomes the downlink data signal 116a,
Outputs 2106b respectively correspond to downlink data signal 116b.

Next, an example of a communication system using the node device of this embodiment is shown in FIG. 22, and its operation will be described in detail. Reference numeral 2202 denotes a signal path determination unit which determines paths for all communication performed in the communication system shown in FIG. The signal path determination unit 2202 is the same as that of the first
Is the same as

Reference numeral 2201 denotes a route device which does not use the functions related to the uplink frequency selection unit 101 and the downlink frequency selection device 103 of the signal path selection device of the present invention. However, the difference is that the uplink control signal input from the node device is transmitted to the signal path determination unit 2202, and then the control signal from the signal path determination unit 2202 is transmitted as a downlink control signal to each downstream node device. I have.

Reference numerals 2203 and 2204 denote node devices.
Reference numerals 2205, 2206, 2207, and 2208 denote terminal devices. Terminal devices 2205, 2206, 2207, 220
Reference numeral 8 has a function of performing modulation on one uplink channel and demodulation from one downlink channel, and further has a function of transmitting one uplink control signal to a node device in the upstream direction.
It has a function of receiving two downlink control signals from the controller in the upward direction.

Node device A 2203 and route device 220
1 is an uplink data signal 2213a and a downlink data signal 22
13b, uplink control signal 2219a, downlink control signal 221
9b.

Similarly, the node device B 2204 and the route device 2201 are connected by an uplink data signal 2214a, a downlink data signal 2214b, an uplink control signal 2220a, and a downlink control signal 2220b.

Node device A 2203 and terminal device A 220
5 is an uplink data signal 2209a and a downlink data signal 22
09b, uplink control signal 2215a, downlink control signal 221
5b.

Further, the other node devices and the terminal device are similarly connected by four signals.

Node device A 2203, node device B22
04, the input / output system on the left side of the route device 2201 will be described as a down direction A, and the input / output system on the right side will be described as a down direction B below.

The management table inside the signal path determination unit 2202 is the same as that in the first embodiment, and is shown in FIG.

The format of the control signal is basically the same as that of the first embodiment, and is shown in FIG. Some differences will be described below.

(2) Node Control Data Format When the root device sends a control signal to the node device or the terminal device, when the node device sends a control signal to the node device, the terminal device or the route device, the terminal device Used to send a control signal to a terminal device, node device, or route device.

Destination: destination for sending node control data Input system: [1] When destination is node device Up direction (input), down direction A (input), down direction B
(Input).

[2] When the destination is a terminal device Meaningless [3] When the destination is a root device Either the down direction A (input) or the down direction B (input) is specified.

Input channel: [1] In the case where the destination is a node device From among the channels input to those specified in the above input system, which channel is to be selected is specified.

[2] When the destination is a terminal device It is determined which channel is to be selected from the downlink channels.

[3] When the Destination is a Root Device The channel to be selected among the channels input to the channel specified by the above input system is specified.

Output system: [1] When destination is node device: Up direction (output), down direction A (output), down direction B
(Output).

[2] When the destination is a terminal device No meaning [3] When the destination is a route device Either the down direction A (output) or the down direction B (output) is specified.

Output channel: [1] When the destination is a node device This specifies which channel is to be selected from the channels output from those specified in the above output system.

[2] When destination is terminal device Which channel is selected from uplink channels is determined.

[3] When the destination is a node device The user specifies which channel is to be selected from the channels output from those specified in the above output system.

FIGS. 23, 24, and 25 show examples of the initial state of the management table of the communication system of FIG. The initial states of the terminal information management table and the communication information management table are the same as in FIG. 8 of the first embodiment.

Reference numeral 2301 in FIG. 23 denotes a node device A 220
9 is a node device information management table for No. 3; Regarding the uplink (output) system, the “channel” of the channel information is “1, 2, 3, 4”, the “status” is all “unused”, the “communication number” is blank, "Attributes" are all "analog". The “connection destination” is a “root device”.

Therefore, the node apparatus A 2203 can output 1, 2, 3, and 4 channels with respect to the uplink (output) system, and each of the nodes performs analog communication. The status is unused, and the communication number is blank. The upstream (input) system is the same as the upstream (output) system.

Regarding the downlink A (input) system, the “channel” of the channel information is “1”, the “state” is “unused”, the “communication number” is blank, and the “attribute” Is "analog". The “connection destination” is “terminal device A”. Therefore, the node device A 2203
In the down-stream (input) system, the channel that can be input is channel 1, the channel 1 is performing analog communication, and since it is an initial state, the state is unused and the communication number is blank.

The downstream A (output) system, the downstream B (input) system, and the downstream B (output) system are the same as the downstream A (input) system.

In FIG. 24, reference numeral 2401 denotes a node device B220.
4 is a node device management table for No. 4. The contents are the same as in the node device information management table 2301.

[0200] Reference numeral 2501 in FIG.
9 is a node device information management table relating to FIG. For the upstream (output) system and the upstream (input) system,
do not use.

Regarding the downlink A (input) system, the “channel” of the channel information is “1, 2, 3, 4”, the “status” is all “unused”, and the “communication number”
Is blank, and all "attributes" are "analog".
The “connection destination” is “node device A”. Therefore, the route device 2201 has 1, 2, 3, and 4 channels that can be input in the downstream A (input) system, and each channel performs analog communication. Not used, communication number is blank.

The downstream A (output) system, the downstream B (input) system, and the downstream B (output) system are the same as the downstream A (input) system.

In the communication system shown in FIG. 4, how communication is actually performed is shown in FIGS. 22, 5, 26, and 2.
This will be specifically described with reference to FIG. 28 and FIG.

Terminal A 2205 and Terminal D 2207
A case where communication is performed with will be described. Communication is performed in the following procedure.

(1) The terminal device A 2205 creates communication request data according to the communication request data format. The communication request data becomes like the communication request data 2601 in FIG. The communication request data 2601 is
This means that a request is made to the root device 2201 to set a communication path between the terminal device A 2205 and the terminal device C 2207 using only analog signals.

(2) The communication request data 2601 is transmitted as the uplink control signal 2215a. Then, the node device A2
The transmission request data 2601 finally arrives at the route device 2201 via the uplink control signal 2219 a via the communication device 203.

(3) The route device 2201 sends the arriving communication request data 2601 to the signal route determining unit 2202.

(4) The signal path determination unit 2202 determines an optimal communication path by the optimization unit 503 based on the communication request data 2601 and the management table 504. The contents of the management table 504 after the communication path is determined include the communication information management table 2602 in FIG. 26, the node device information management table 2701 in FIG. 27, the node device information management table 2801 in FIG. 28, and the node device information management table 29 in FIG.
01.

In the communication information management table 2602, “communication number” is “1”, “source terminal name” is “terminal device A”, “destination terminal name” is “terminal device D”, and “attribute” is “attribute”. Communication between the terminal device A and the terminal device D is recorded as "analog".

When the node device information management table 2701 is
The difference from the node device information management table 2301 in the initial state is as follows: Regarding the upstream (output) system, the “state” of the channel 1 item of the channel information is “in use” and the “communication number” is “1”. Has become.

Regarding the downlink A (input) system, the “status” of the channel 1 item of the channel information is “in use”
In addition, the “communication number” is “1”. That is to say. The node device A 2203 uses each channel of the above system.

When the node device information management table 2801 is
The difference from the node device information management table 2401 in the initial state is as follows: Regarding the upstream (input) system, the “state” of the channel 1 item of the channel information is “in use” and the “communication number” is “1”. Has become.

Regarding the downlink B (output) system, the “status” of the channel 2 item of the channel information is “in use”
In addition, the “communication number” is “1”. That is to say. The node device B 2204 uses each channel of the above-described system.

When the node device information management table 2901 is
The difference from the node device information management table 2501 in the initial state is as follows: Regarding the downlink A (input) system, the “state” of the channel 1 item of the channel information is “in use” and the “communication number” is “1”. It has become.

Regarding the downlink B (output) system, the “status” of the channel 2 item in the channel information is “in use”.
In addition, the “communication number” is “1”. That is to say. The root device 2201 uses each channel of the above-described system.

As described above, the signal path determined by the signal path determining section 2202 is as follows.

[1] Terminal apparatus A 2205 uses uplink channel 1 and outputs it as uplink data signal 2209a. The output is output from the node device A 2203 in the downstream direction A.
This is an input to the (input) channel 1 (uplink data signal 2209a).

[2] The node device A 2203 outputs the channel 1 of the downstream A (input) system as the channel 1 of the upstream (output) system. The output is route device 2
It is input to the channel 1 of the downlink A (input) system 201 (uplink data signal 2213a).

[3] The route device 2201 is
The channel 1 of the (input) system is returned to the channel 1 of the downstream B (output) system as it is. The output is the channel 1 of the upstream (input) system of the node device B2204.
(Downlink data signal 2214b).

[4] The node device B 2204 outputs the channel 1 of the upstream (input) system as the channel 2 of the downstream B (output) system. Here, the node device B22
04 performs frequency conversion in the down direction. The output is input to the downlink channel 2 of the terminal device D2207 (downlink data signal 2212b).

[5] The terminal device D2207 receives data from the downlink channel 2. Data from the terminal device A 2205 is transmitted to the terminal device D 2208 via the above route.

(5) In order to set the above route, the signal route determining unit 2202 sends the node control data 260
Create 3.

The following describes the node control data 2603. The node control data sent to the route device 2201 is such that “destination” is “route device”, “input system” is “downstream A”, “input channel” is “1”, and “output system” is “downstream direction”. B ”and“ output channel ”are“ 1 ”. With this node control data, the root device 2201
Outputs the channel 1 of the downstream A (input) system to the channel 1 of the downstream (output) system as it is.

The node control data sent to the node device A 2203 is such that the “destination” is “node device A”, the “input system” is “downstream A”, the “input channel” is “1”, and the “output system”. Is “up” and “output channel” is “1”. With this node control data, the node device A 2203 outputs the channel 1 of the downstream A (input) system to the channel 1 of the upstream (output) system as it is.

The node control data sent to node device B 2204 is the same as that of node device A 2203.

(6) Finally, the node control data 2603
Is transmitted to each node device, thereby completing the route setting.

In the conventional CATV network, it was impossible to realize the above communication. In the conventional CATV network, data transmitted from the terminal device A 2205 on the uplink channel 1 is returned to the downlink channel 1 at the head end and does not reach the terminal device D 2208. On the other hand, if the node device of the present invention is used, frequency conversion in the downlink direction is possible, so if the frequency conversion is performed on downlink channel 1 to downlink channel 2, communication between terminal device A 2205 and terminal device D 2208 is possible. Becomes

In this embodiment, the node device B 220
Although the downlink frequency conversion function of No. 4 is used, the same can be achieved by using the return direction frequency conversion function of the route device 2201.

Further, in this embodiment, the case where the terminal device can transmit and receive only one channel has been described. However, the present invention can easily cope with a terminal device which can transmit and receive a plurality of channels. For example, a modulation / demodulation circuit in the terminal device may be controlled by a downlink control signal connected to the terminal device.

Although the present embodiment has been described with respect to a case where there are two inputs to the node device, the present invention can easily cope with a case where there are more inputs. For example, what can be realized by extending the contents of the management table can be easily analogized.

Further, in this embodiment, even if the number of physical transmission lines for transmitting the four signals of the uplink data signal, the downlink data signal, the uplink control signal, and the downlink control signal is one, a plurality of physical transmission lines are required. It can easily be inferred that it is adaptable.
It can be easily analogized that the control signal can be transmitted and received using a public line.

(Embodiment 4) An embodiment in which the signal path selection device of the present invention is applied to a cable television will be described with reference to FIG. In FIG. 30, reference numeral 3005 denotes a signal path selection device of the present invention, which is hereinafter referred to as a relay device. A transmission path 3001 transmits a plurality of programs by frequency division multiplexing.
This is a coaxial cable or optical fiber cable that multiplexes multiple programs.

[0233] Reference numeral 3006 denotes a transmission line similar to 3001, and in this description, it is assumed that the line is a subscriber line in a cable television in which 60 programs are frequency-division multiplexed. 3002
Is a downlink frequency conversion unit that selects a program that needs to be relayed to the transmission line 3006 among programs multiplexed on the transmission line 3001, converts the program to a different frequency, and outputs the converted frequency.
Hereinafter, it is referred to as a conversion unit. Note that signals input and output by the conversion unit 3002 may be either electrical signals or optical signals, and the optical signals may be converted to electrical signals as needed.

Reference numerals 3003-1 to 300n denote terminal devices that select and receive a desired program from the frequency multiplexed output from the conversion unit 3002 based on information from a control unit 3004, which will be described later. Have. 3004 is
It has a storage means inside, stores a frequency management table shown in (Table 1), inputs a program distribution request signal from each of the terminals 3003-1 to 300n, and controls the control unit 30 based on the request signal.
04 outputs a relay request signal to converter 3002 to relay the program.

[0235]

[Table 1]

Note that the relay request includes input frequency information of a program to be relayed and information of an output frequency after frequency conversion. The frequency management table will be described using (Table 1). In Table 1, the reception frequency is the frequency of a program frequency-division multiplexed on the transmission path 3001, the program name is the program name of each program, the transmission frequency is the frequency when each program is output to the transmission path 3006, and the receiving terminal is It is a list of terminals receiving the program. Further, the program name may be replaced with a broadcast station name.

The operation of the above configuration will be described. First, it is assumed that the relay device is not relaying the program.
At this time, the frequency management table in the control unit 3004 is as shown in (Table 2).

[0238]

[Table 2]

In this state, suppose that terminal 3003-1 wants to receive program C. The terminal 3003-1 receives the program C
Is transmitted to the control unit 3002.
This request includes the program name “Program C” and the terminal 30
03-1 is included. The control unit 3004 finds “Program C” by referring to the program name column of the table, and refers to the corresponding transmission frequency column. In this case, "0" means that this program is not currently being relayed, so it is necessary to open a new relay.

The control unit 3004 looks at the column of the transmission frequency,
Find a free frequency to use for transmission. In this description, it is assumed that “frequency 1” is selected as a free frequency. At this time, if all transmittable frequencies have been used, no more relays can be established. The control unit 3004 requests the conversion unit 3002 to receive the frequency 3, convert it to the frequency 1 and output it, and notifies the terminal 3003-1 to receive the frequency 1. The terminal 3003-1 receives the notified frequency and receives the requested program C.

When terminal 3003-1 ends receiving program C, terminal 3003-1 notifies control unit 3004 of that fact. The control unit 3004 deletes the terminal 3003-1 from the receiving terminal column of the table. In this case,
Since there is no longer a terminal that receives program C, there is no need to continue relaying program C. Therefore, the control unit 3004
002 to stop transmitting frequency 1.
The transmission frequency column of the program C in the table is set to 0.

[0242] The program reception request issued by terminal 3003-1 includes information on the time at which the user wants to continue receiving the program, and stores the information on the time in a table of control unit 3004. An operation to determine the end of reception is also possible. In addition, a signal for confirming whether or not the receiving terminal is actually in the receiving state is sent to all of the receiving terminals stored in the table at a fixed time period, for example, every 10 minutes, and each terminal actually receives the signal. If the reception has been performed, the operation to notify that effect to the control unit 3004 is performed, the terminal that does not return a normal response to the control unit 3004 is deleted from the reception terminal column of the table, and the same operation as when the reception is completed is performed. It is also possible to perform the operation.

In such a case, the control unit 3004 can detect the end of reception even when a failure occurs in the terminal or transmission path during reception and the end notification does not reach the control unit 3004 even if reception is interrupted. It has the effect.

In the future, it is expected that the number of channels of cable television will increase. Along with this, it is expected that the transmission facilities will also need to increase the bandwidth accordingly. However, even if the cable television has more channels than it is now, actually viewed programs are biased, and many viewers are expected to concentrate on popular programs. Therefore, it is not always necessary to actually supply all of the programs that can be supplied, and it is sufficient to supply only the programs that are requested to be received.

By using the present invention, it is possible to relay a multi-channel program exceeding the transmission band of an existing cable television subscriber line in response to a request from a viewer.

[0246] Since the receiving terminal is registered in the frequency management table, by keeping a record of this table, the audience rating of the total survey can be totaled.

It is preferable that control signals between terminal 3003 and control section 3004 be exchanged between transmission lines 3006, but it is also possible to use a dedicated control line or a telephone line.

Furthermore, instead of exchanging control signals between terminal 3003 and control section 3004, control section 30
04 is provided with a telephone answering device, and the subscriber can perform an operation of sending a program reception request to be viewed to the control unit 3004 by a DTMF signal using a telephone. In this case, the telephone answering apparatus of the control unit 3004 may notify the subscriber of the frequency to be received at the receiving terminal by voice guidance.

Also, conversion section 3002 transmits terminal 3003-1
To n, if a program with a high rating is relayed constantly through a fixed channel, and if a program with a high rating is to be viewed, the control unit 3004 is sent from the terminal 3003-1 to n.
There is an advantage that it is not necessary to send a reception request to the user.

(Embodiment 5) A fifth embodiment of the present invention will be described below with reference to FIG. Reference numerals 3105-1 and 310-2 denote the same relay devices as in the fourth embodiment. Relay device 3105-2
Is arranged in place of the receiving terminal in the fourth embodiment, and the fifth embodiment is different from the fourth embodiment in that a configuration in which a relay device relays a program to another relay device is made possible.

In the description of this embodiment, it is assumed that the transmission path 3101-1 transmits 500 programs by frequency division multiplexing, and the transmission path 3101-2 frequency multiplexes 100 programs.

The operation of the above configuration is described in the fourth embodiment.
It will be described in light of the above. Relay device 3105-1 of the present embodiment
Is illuminated by the relay device 3005 of the fourth embodiment, the terminal 3
103-1 to 103-n, the relay device 31
There is a program reception request from 05-2. Opening and interruption of the relay are performed in the same manner as in the fourth embodiment. Next, the relay device 3105-2
The operation will be described with reference to the relay device 3005 of the fourth embodiment. The relay apparatus 3105-2 processes the reception requests of the receiving terminals 3104-1 to 3104-1n, as in the fourth embodiment. For example, when the terminal 3104-1 requests reception of “Program D”, when “Program D” is not in the column of the program name in the frequency management table of the relay device 3105-2, the relay device 3105-2 is connected to the relay device 3105-2. A reception request for “program D” is sent to 3105-1. Upon receiving the supply of “Program D” from the relay device 3105-1, the relay device 3105-2 registers the frequency in the frequency management table, performs the same operation as that of the fourth embodiment, and receives the signal from the terminal 3104-1. Meet your requirements.

The relay device 3105-2 is connected to the terminal 31.
Since it is not necessary to relay programs that have not been received in 04-1 to 04-n, a request to terminate reception is sent to the relay device 3105-1 as soon as such a program occurs. This is performed in the same manner as the terminal termination request.

In this embodiment, even if the cable television program transmission network has a hierarchical structure, the program can be supplied by dynamic frequency allocation. Therefore, even a cable television subscriber with a small transmission capacity can enjoy a variety of program options.

(Embodiment 6) An embodiment in which the relay apparatus of the present invention is applied to a program transmission network will be described with reference to FIG. The difference from the fifth embodiment is that there are a plurality of signal sources of the program multiplexed on the transmission path 3202. That is, the program from the transmission path 3201-0 and the transmission path 3201
There are programs that are multiplexed on the transmission line 3202 after the programs from −1 to n are frequency-converted by the relay devices 3205-1 to n. In addition, a frequency management device is provided on the transmission path 3202 for managing programs and frequencies to be frequency division multiplexed.

A management table shown in (Table 3) is provided inside the frequency management device, and stores a program name that can be provided on the transmission line 3202, a transmission source of the program, and a frequency of the program during transmission.

[0257]

[Table 3]

The operation of the above configuration will be described.
The difference from the fifth embodiment is that the terminal 3203 and the relay device 320
The point is that the program reception request and the program reception end request from 6-1 to n are sent to the frequency management device 3204. Upon receiving the program reception request, the frequency management device 3204 searches for a program name in an internal table. If there is a description in the frequency column, the program has already been transmitted on the transmission path 3202.
The terminal or relay device that has issued the reception request is informed of the frequency, and the reception request is satisfied. If the transmission source is a relay device, the reception request is sent to the transmission source relay device. If there is no description in the frequency column, it means that the program is not yet being transmitted, so the frequency management device 3204 searches for an available transmittable frequency, records the frequency in a table, and receives a reception request and a relay including the available frequency. Send the request to the source relay device.
Note that the program whose transmission source is the transmission path 3201-0 has its frequency and program name registered in a table in the frequency management device 3204 in advance. The operation of the relay apparatus is the same as that of the fifth embodiment except that the transmission management apparatus 3204 has the right to determine the transmission frequency.

[0259] With the development of cable television in the future, there will be no single source of programs, and terrestrial television broadcasting,
It may be necessary to provide a network of programs consisting of multiple program sources, such as other cable television networks and in-house broadcasting. By using the present invention, programs from a plurality of signal sources can be dynamically frequency-division multiplexed within a limited frequency band, and abundant program options can be provided to a viewer.

[0260]

As described above, by using the signal path selection device of the present invention, it is possible to effectively use channels in a communication system that performs transmission by the frequency division multiplexing method. In addition, programs from a plurality of signal sources can be dynamically frequency-division multiplexed within a limited frequency band, thereby providing abundant program options to the viewer.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a communication route selection device according to a third embodiment of the present invention.

FIG. 2 is a conceptual diagram of a communication path selection device according to the first embodiment of the present invention.

FIG. 3 is a block diagram schematically showing an uplink frequency converter according to the present invention;

FIG. 4 is a block diagram showing a system configuration according to first and second embodiments of the present invention;

FIG. 5 is a block diagram schematically showing a signal path determining unit according to the present invention;

FIG. 6 is a schematic diagram of a management table of a signal path determination unit according to the present invention.

FIG. 7 is a diagram showing a format of communication data according to the embodiment of the present invention.

FIG. 8 is a first initial state diagram of a management table according to the first and second embodiments of the present invention.

FIG. 9 is a second initial state diagram of the management table according to the first and second embodiments of the present invention.

FIG. 10 is a third initial state diagram of the management table according to the first and second embodiments of the present invention.

FIG. 11 is a first conceptual diagram of a management table and control data according to the first embodiment of the present invention.

FIG. 12 is a second conceptual diagram of a management table and control data according to the first embodiment of the present invention.

FIG. 13 is a third conceptual diagram of a management table and control data according to the first embodiment of the present invention.

FIG. 14 is a fourth conceptual diagram of a management table and control data according to the first embodiment of the present invention.

FIG. 15 is a fifth conceptual diagram of a management table and control data according to the first embodiment of the present invention.

FIG. 16 is a sixth conceptual diagram of a management table and control data according to the first embodiment of the present invention.

FIG. 17 is a conceptual diagram of a communication path selection device according to a second embodiment of the present invention.

FIG. 18 is a conceptual diagram showing a configuration of a folding direction frequency conversion unit of the present invention.

FIG. 19 is a first conceptual diagram of a management table and control data according to a second embodiment of the present invention.

FIG. 20 is a second conceptual diagram of a management table and control data according to the second embodiment of the present invention.

FIG. 21 is a conceptual diagram showing the configuration of a downlink frequency converter according to the present invention.

FIG. 22 is a conceptual diagram of a communication path selection device according to a third embodiment of the present invention.

FIG. 23 is a first initial state diagram of a management table in the third embodiment of the present invention.

FIG. 24 is a second initial state diagram of the management table in the third embodiment of the present invention.

FIG. 25 is a third initial state diagram of the management table in the third embodiment of the present invention.

FIG. 26 is a first conceptual diagram of a management table and control data according to a third embodiment of the present invention.

FIG. 27 is a second conceptual diagram of a management table and control data according to the third embodiment of the present invention.

FIG. 28 is a third conceptual diagram of a management table and control data according to the third embodiment of the present invention.

FIG. 29 is a fourth conceptual diagram of the management table and the control data in the third embodiment of the present invention.

FIG. 30 is a conceptual diagram of a communication path selection device according to a fourth embodiment of the present invention.

FIG. 31 is a conceptual diagram of a communication path selection device according to a fifth embodiment of the present invention.

FIG. 32 is a conceptual diagram showing the configuration of a program transmission system according to a sixth embodiment of the present invention.

FIG. 33 is a conceptual diagram showing a configuration of a communication system in a conventional technique.

[Explanation of symbols]

 Reference Signs List 101 Upward frequency converter 102 Return direction frequency converter 103 Downward frequency converter 104 Uplink distributor 105 Downlink mixer 106 Node controller 201 Upward frequency converter 202 Returning frequency converter 203 Node controller 402 Signal Route determination unit 1701 Upward frequency conversion unit 1702 Return direction frequency conversion unit 1703 Downstream frequency conversion unit 2201 Route device 2202 Signal route determination unit 2203 Node device A 2204 Node device B 2205 Terminal device A 2208 Terminal device D 3002 Downlink frequency conversion Unit 3004 control unit 3001 transmission line 3204 frequency management device

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-207689 (JP, A) JP-A-63-279688 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H04J 1/00 H04N 7/173

Claims (6)

(57) [Claims] 1. A plurality of frequency division multiplexed signal sources
Frequency division multiplexing on one transmission line by wave number conversion
A program transmission system in which a program name and a program transmitted on a transmission path are multiplexed.
Management table including frequency and program signal source and transmission path
To the transmission path based on the program reception request from the terminal connected to
A frequency management device for requesting the output of a program, and a plurality of
Signal path for frequency conversion of frequency division multiplexed signal source
The signal path selecting apparatus , wherein the signal path selecting apparatus distributes a downlink data signal, which is a frequency division multiplexed signal, to a plurality of downlink data signals, and an uplink data, which is a plurality of systems of frequency division multiplexed signals. An upstream frequency conversion unit for converting an arbitrary frequency in the signal to another frequency and mixing it into one system of upstream data signal; and an arbitrary frequency in the upstream data signal on the input side of the upstream frequency conversion unit to the output side. any and node control unit which determines based on the control signal conversion to frequency, program transport with a sheet of in uplink data signal
Stem . 2. A method for transmitting a signal to a plurality of frequency division multiplexed signal sources.
Frequency division multiplexing on one transmission line by wave number conversion
A program transmission system in which a program name and a program transmitted on a transmission path are multiplexed.
Management table including frequency and program signal source and transmission path
To the transmission path based on the program reception request from the terminal connected to
A frequency management device for requesting the output of a program, and a plurality of
Signal path for frequency conversion of frequency division multiplexed signal source
The signal path selecting apparatus , wherein the signal path selecting apparatus distributes a downlink data signal, which is a frequency division multiplexed signal, to a plurality of downlink data signals, and a plurality of uplink data signals, which are frequency division multiplexed signals. An upstream distributor for distributing to an upstream data signal of a system, and an upstream for converting an arbitrary frequency in the upstream data signals output from the plurality of upstream distributors to another frequency and mixing it into one system of upstream data signal. A direction frequency conversion unit, and converts an arbitrary frequency in the uplink data signal output from the plurality of uplink distributors to another frequency, and a return direction frequency conversion unit that distributes the downlink data signals to a plurality of systems; A downlink mixer for mixing a downlink data signal output from the return frequency converter and a downlink data signal output from the downlink distributor; The conversion from an arbitrary frequency in the uplink data signal on the input side of the directional frequency converter to the arbitrary frequency in the uplink data signal on the output side, and the arbitrary frequency in the uplink data signal on the input side of the return direction frequency converter. and a node controller to determine the conversion to an arbitrary frequency in the output side of the downlink data signal based on a control signal from, with a program transport sheet
Stem . 3. A plurality of frequency division multiplexed signal sources
Frequency division multiplexing on one transmission line by wave number conversion
A program transmission system in which a program name and a program transmitted on a transmission path are multiplexed.
Management table including frequency and program signal source and transmission path
To the transmission path based on the program reception request from the terminal connected to
A frequency management device for requesting the output of a program, and a plurality of
Signal path for frequency conversion of frequency division multiplexed signal source
And a selection device, wherein the signal path selection device converts an arbitrary frequency in the downlink data signal being a frequency division multiplexed signal to another frequency and distributes it to a plurality of systems of downlink data signals. An uplink distributor that distributes an uplink data signal, which is a frequency division multiplexed signal, to a plurality of uplink data signals, and an arbitrary frequency in the uplink data signals output from the plurality of uplink distributors to another frequency. And an upstream frequency conversion unit for converting an arbitrary frequency in the upstream data signals output from the plurality of upstream distributors to another frequency and converting the same to another system. A return direction frequency converter for distributing to a signal, and a downlink data signal output from the return direction frequency converter and an output from the downlink frequency converter. A downstream mixer for mixing the downstream data signal into one system of downstream data signals; and an arbitrary frequency in the upstream data signal on the input side of the upstream frequency converter from an arbitrary frequency in the upstream data signal on the output side. And the conversion from an arbitrary frequency in the upstream data signal on the input side of the return direction frequency converter to an arbitrary frequency in the downstream data signal on the output side, and a downstream data signal on the input side of the downstream frequency converter. program transmission system and a node control section for determining based on a control signal conversion to an arbitrary frequency in the downlink data signal output from the arbitrary frequency in. 4. A plurality of frequency division multiplexed signal sources
Frequency division multiplexing on one transmission line by wave number conversion
A program transmission system in which a program name and a program transmitted on a transmission path are multiplexed.
Management table including frequency and program signal source and transmission path
To the transmission path based on the program reception request from the terminal connected to
A frequency management device for requesting the output of a program, and a plurality of
Signal path for frequency conversion of frequency division multiplexed signal source
The signal path selecting apparatus , the signal path selecting apparatus converts an arbitrary frequency in the downlink data signal which is a frequency division multiplexed signal to another frequency and outputs the same, and an input uplink frequency converter. program transport system comprising, based on the received request signal is a signal, and control means for controlling the frequency of dynamically the downlink frequency converting unit. 5. A downlink data signal which is a frequency division multiplex signal.
Convert any frequency in the signal to another frequency and output
Directional frequency converter and the input upstream or downstream signal
The downlink frequency is dynamically determined based on a reception request signal.
Control means for controlling the frequency of the conversion unit, wherein the request signal is transmitted from a receiving terminal or another signal path selecting device.
A signal path selecting device. 6. A downlink data signal which is a frequency division multiplex signal.
Convert any frequency in the signal to another frequency and output
Redirection frequency converter, and a reception request signal that is an input uplink or downlink signal,
Dynamically based on the data signal reception status.
Control means for controlling the frequency of the direction-frequency conversion unit.
The signal routing device.