JPS63206039A - Multi-channel access communication system - Google Patents

Abstract

PURPOSE:To always attain polling even when all communication channels are used by sharing the outgoing state of a control channel with the outgoing state of polling and providing a polling incoming-only channel. CONSTITUTION:In collecting a data by the polling, polling is requested from the CPU 11 of a center 10 to an MCA communication equipment 12 at first. The MCA communication equipment 12 applies polling to a specified MCA terminal equipment 17 through a control channel. The MCA terminal equipment 17 subjected to polling switches the channel to the polling incoming-only channel and informs the connection to the polling reply terminal 18. The polling reply terminal 18 applies the polling reply to the CPU of the center 18' through the polling incoming-only channel.

Description

Detailed Description of the Invention Overview In a multi-channel access (abbreviated as MCA under IX) communication system that performs data communication between a center and terminals and between terminals via the center in two-way CATV, polling is used to When collecting data for t
The downlink of the IIwJ channel is shared with the downlink of polling, and the polling response uses a separately provided uplink exclusive channel, thereby making it possible to perform polling even when the communication channel is congested.

INDUSTRIAL APPLICATION FIELD OF THE INVENTION The present invention relates to a multi-channel access communication system for data communication within bidirectional CATV.

CATV is a new communication network that uses coaxial cables, and has been used primarily for transmitting information centered on television images. Initially, it was used exclusively as equipment to prevent television viewing difficulties, but in recent years, with the development of a regional information society, coaxial cables have been considered as a social system that can transmit large amounts of information by taking advantage of their characteristics. ing.

In recent years, two-way CATV, which has the function of an interactive communication network that enables not only one-way transmission but also two-way transmission, has become one of the new media that uses such CATV systems.
is being developed. This is a wired communication equipment for CATV that adds a function to send signals from the subscriber's terminal to the center, making it possible to communicate in both directions. Various services can be provided in response to requests from subscribers, such as home security services and pay-bar-view services that provide individual programs selected by subscribers for a fee.

Bidirectional CATV transmission systems usually use a single coaxial cable and transmit downlink signals from center equipment to subscribers in the upper band, and uplink signals in the opposite direction in the lower band. method is used.

MC that performs data communication within such two-way CATV
In communication method A, a large number of subscriber terminals jointly use multiple communication channels for mutual data communication, and when communicating between each subscriber terminal and the center or between subscriber terminals via the center, When a connection request to that effect occurs, data communication is performed by allocating a vacant communication channel to both parties. However, even when data from each terminal is collected through polling, such as in an automatic meter reading service, data cannot be collected until each terminal is called one by one and a communication channel is assigned. Therefore, in the MCA communication system, it is desired that polling-based communication can be performed efficiently and constantly.

BACKGROUND OF THE INVENTION FIG. 6 shows a block diagram of an MCA communication system for performing data communication within a two-way CATV. In the figure, 1 is a CATV center, which includes a central processing unit (hereinafter referred to as CPU) 1a for data communication, and an MCA communication device l.
b, and a head end 1C. 2 is the coaxial cable transmission line connected to the head end 1C, 3 3
... is a bidirectional branch amplifier installed in transmission line 2, 4.4□
.

... is a subscriber connected to each bidirectional branch amplifier,
These subscribers are equipped with an MCA terminal device 4a and terminals 4b connected to it, such as a personal computer, television, security service sensor, etc., and the terminal 4b and the center's CPLJ
Data communication between la is done by MCA communication device! ! 1b and MC
This is realized by the A terminal device 4a.

In addition, in such a communication system, because uplink and downlink lines are configured on the same transmission route, the frequencies used for data communication are, for example, the lower band of the transmission route for the uplink and the upper band for the downlink. is assigned to.

Figure 7 shows a logical image of the channel configuration of the MCA system, and for mobile communication systems and rtR, one control channel ch0, multiple communication channels ch0,
, ch2. ...ch, and each of these channels is connected to the MCA communication device 1b and the MCA terminal device 4a, respectively.

FIG. 8 is for explaining the outline of the communication procedure of the communication system configured as described above.

When performing data communication between CPLJla of center 1 and terminal 4b, first communicate with center 1 through control channel Cho.
sends a channel allocation request to the other side.

At this time, if data communication is with center 1, a connection request with center 1 is made. Along with this, the MCA communication device 1b of the center 1 checks the usage status of communication channels and instructs the subscriber side MCA terminal device 2f4a to use an empty communication channel.

Upon receiving this, the MCA terminal device 4a switches to the specified communication channel and communicates with CPLJla of the center 1 and the terminal 4b.
enable communication between Furthermore, when the data communication ends and a disconnection request is sent from the terminal 4b via the MCA terminal device 4a, the disconnection request is sent to the center side through the control channel. The center 1 side gives a disconnection instruction to the terminal side through the control channel, thereby disconnecting the communication channel between the two.

Next, the conventional operation f order when collecting terminal data by polling using the MCA communication system will be explained with reference to FIG. First, the MC that attempts to collect data from the center CPU1a to the center MCA communication device fi1b
Output the A terminal number and request a connection. Upon receiving this connection request, the MCA communication device 1b searches for free communication channels, selects one of them, and designates the communication channel to the MCA terminal f2R4a. At this time, M on the center side
The downlink data format sent from the CA communication device 1b to the MCA terminal 4a on the subscriber side through the control channel has a channel designation and a channel number code added to the MCA terminal number, as shown in FIG. Become something.

The MCA terminal device 4a that has received the channel designation switches its communication channel to the designated channel and sends a switching response signal to that effect back to the center MCA communication device 1b through the communication channel. After that, the MCA communication device 1b
At the same time as notifying the CPU 1a of channel connection, the MCA terminal device 4a on the subscriber side sends a polling response terminal 4b.
The channel connection is notified to the center C.
Polling is performed from the PU 1a to the polling response terminal 4b through the communication channel. Then, data is returned from the terminal 4b in response to this polling.

When data collection by the center CPU 1a is completed, the CPU
1aG sends a channel disconnection request to the tMCA communication device 1b. Upon receiving this, the MCA communication device 1b instructs the polling-responsive WOE terminal side MCA terminal device 4a to disconnect the channel through the control channel, disconnects the designated channel to the terminal, and ends the process.

Thereafter, in the same manner, each free communication channel is sequentially connected to the MCA terminal and polled.

Problem to be Solved by the Invention When collecting data by polling using the conventional MCA communication system as described above, it is necessary to sequentially call each terminal, allocate a communication channel to each terminal, and then collect terminal data through data communication. Therefore, the data collection speed is slow, and if all communication channels are used, polling cannot be performed at all.

In addition, if automatic meter reading service and PC communication service are performed using two-way CATV, polling equipment and M
There is a problem in that each CA communication device is required and the communication equipment becomes complicated.

The present invention was created in view of the above points, and its purpose is to enable polling at all times even when all communication channels are in use, and to improve line switching system communication (PC communication, etc.). and polling communication (
The objective is to provide an MCA communication method that enables automatic meter reading, etc.) in the same system.

To solve problem 11 FIG. 1 shows a block diagram of the principle of the present invention.

In the figure, reference numeral 10 denotes a center, which includes a central processing unit 5A (hereinafter referred to as CPU) 11 for data communication, and an MCΔ communication device 12 having polling uplink dedicated channel reception means 13.
and a head end 20. The center 10 connects the subscribers 14 . 14, . . . and these subscribers are connected to MCA
It consists of an fQ terminal device 17 and a terminal 18. Also, the center 10 and the subscriber 14. 14, . . . consists of a control channel, a polling uplink dedicated channel, and a plurality of communication channels.

Operation-L When data is collected by polling using the multi-channel access communication system of the present invention configured as described above, first, data is collected from the CPU 11 of the center 10 to the MCA
A polling request is made to the communication device 12. MCA
The communication device 12 polls a specific MCA terminal device 17 through a control channel. polled M
The CA terminal device 17 switches the channel to the polling uplink dedicated channel and notifies the polling response terminal 18 of the connection. This means that the polling connection is completed, and the polling response terminal 18
A polling response is sent to the PU 11 using a polling uplink dedicated channel.

That is, in response to polling from the center 10, data is returned from the terminal 18 via the polling uplink exclusive channel.

As described above, according to the present invention, by providing a polling uplink dedicated channel, polling can always be performed even if all communication channels are in use.

衷-Jl The multi-channel access communication system of the present invention will be explained in detail below based on the embodiments shown in the drawings.

FIG. 2 is a block diagram showing an embodiment of the MCA communication system of the present invention.
and an MCA communication device 12. The MCA communication device 12 includes a line control device 122 connected to the CPLll through an interface 121, and a line control device 122 connected to the CPLll through an interface 121.
Control Desinel Transceiver 123 Connected to 1I Device 122
and a plurality of communication channels transmitting/receiving 1fi 1251 connected to the CPLJll via the interface 124.
・Interface 129 to 125o and CPtJll
The polling uplink dedicated channel receiver 128 connected via
25o, and polling uplink dedicated channel receiver 128
The mixer 126 is connected to the transmission line 16 via a head end 127.

In addition, a bidirectional branch amplifier 151゜15 is connected to the transmission line 16.
Subscribers 14.142, . . . connected via , .
The MCA terminal device 17 includes a bidirectional branching amplifier 15 . 1
A transceiver 172 connected to 5□, . a channel switching device 174 that switches the communication channel and the polling uplink dedicated channel to a specified channel; a terminal interface 175 that interfaces the control response device 173 with a line-switched communication terminal 18a such as a personal computer; The Hallings MCA identification device 176 identifies whether the communication is polling or MCA communication and transmits the identification result to the control response device 173, and interfaces the control response device 173 with a polling type communication terminal 18b such as a meter or sensor. and a polling terminal interface 177.

Next, referring to FIG. 3, this figure shows the operating procedure when collecting terminal data by polling.
The operation of this method will be explained based on this figure.

First, a polling request is output from the center CPtJ11 to the MCΔ communication device 12. Upon receiving this, the MCA communication device 12 polls the designated terminal through the control channel. The data format at this time is configured as shown in FIG. 5, and a code indicating polling is added to the conventional connection channel designation part. This data format signal is transmitted to the control channel transceiver 12.
3 to the subscriber side via the downlink control channel,
It is designed to poll the specified terminal.

When the MCA terminal device 17 on the subscriber side corresponds to the polling request, the transceiver 172 receives the signal transmitted through the downlink control channel, and the polling/MCA identification device 176 determines that the signal is a polling signal. If it is identified, it is transmitted to the control response device 173, and the control response device 173 instructs the channel switching device 174 to switch the channel of the transceiver 172 to the polling uplink exclusive channel, and also sends the message to the terminal 18b through the polling terminal interface 177. Notify of connection. Along with this, the data output from the polling response terminal 18b is taken into the control response device 173 via the polling terminal interface 177, and the data output from the transmitter/receiver 17
2 to the center 10 through the polling uplink dedicated channel.
sent to the side.

When the data collection of the MCA terminal that has made the polling request is completed in this way, the control response device 173 of the MCA terminal device 17 instructs the channel switching device W1174 to disconnect the polling and E-only channel of the transceiver 172. and move on to the next operation.

As shown in FIG. 4, the channel configuration of this embodiment described above has a control channel, a plurality of communication channels, and a polling uplink exclusive channel.

In addition, for line-switched communication such as PC communication, the control response device 173 and terminal interface 17 shown in FIG.
However, according to this embodiment, a polling uplink dedicated channel is provided, so even if all communication channels are used by circuit-switched communication such as PC communication, polling is carried out through the polling uplink dedicated channel. Automatic detection [1st class polling type communication can be performed at all times.

Effects of the Invention As detailed above, the MCA communication system of the present invention is configured by sharing the downlink control channel with the downlink polling channel and providing a dedicated uplink channel for the Borig, so that all communication channels are used. This has the effect that polling can always be performed.

In addition, circuit-switched communication such as PC communication and polling-based communication such as automatic meter reading are possible in the same system.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of the principle of the present invention, Fig. 2 is a block diagram showing an embodiment of the invention, Fig. 3 is a diagram showing a polling procedure in an embodiment of the invention, and Fig. 4 is a diagram of an embodiment of the invention. An explanatory diagram showing the channel configuration, FIG. 5 is a diagram showing the control channel downlink data format in the embodiment of the present invention, FIG. 6 is a configuration diagram of a conventional MCA communication system, and FIG. 7 is a channel configuration of the MCA method. Figure 8 is a diagram showing the communication procedure of the communication system, Figure 9 is a diagram showing the polling procedure when polling is performed using the conventional MCA communication method, and Figure 10 is the diagram showing the conventional control channel. FIG. 3 is a diagram showing a downlink data format. 10...center, 11...cpu. 12... MCA communication device, 13... Polling uplink exclusive channel reception means, 14
．． 142...Subscriber, 15.152...Bidirectional branch amplifier, 16...Transmission line, 17...MCA terminal device, 18...
Terminal, 19...Polling/MCAl1 alternative means. # The same figure 3 shows the holing procedure of the Sounbai line. Figure 4: The lower part of the 5th line of the book. Diagram showing Sections 8-9 of Figure 7, Section A

Claims (1)

[Claims] Data communication central processing unit (11) and MCA communication device (
12); and a center (10) having
MCA terminal device (
17) and a terminal (18) connected thereto, a communication system comprising a multi-channel access system channel including a control channel, a polling uplink dedicated channel, and a plurality of communication channels; ) is provided with polling uplink dedicated channel reception means (13), and the MCA terminal device (1
7) is provided with polling/MCA identification means (19) for identifying whether it is polling or MCA communication, and the downlink side of the control channel is shared with downlink polling, and the polling response is transmitted through the polling uplink exclusive channel. A multi-channel access communication method characterized by: