JPS63156452A - Multi-channel access communication system - Google Patents

Abstract

PURPOSE:To perform polling and collect data of plural terminal in a single operation, by polling simultaneously the same number of terminals as that of vacant communication channels when the data collection of the terminal is performed, in a multi-channel access (MCA) system in which data communication between a center and the terminal or between the terminals is performed. CONSTITUTION:Based on a channel acquire request from a CPU11, all of the vacant communication channels retrieved by an MCA communication equipment 12 are informed to the CPU11. According to the above, by informing a terminal polling request corresponding to each vacant channel to the MCA communication equipment 12 by the CPU11, the MCA communication equipment 12 applies the polling on a designated MCA terminal through a control channel. Each corresponding MCA terminal equipment 17, receiving the polling, switches a channel to a designated channel simultaneously, and also, fetches a data from a polling response terminal, and sends it to a center side. Therefore, by polling the same number of terminals as that of the vacant communication channels, it is possible to poll and collect the data of plural terminals in a single operation.

Description

[Detailed Description of the Invention] [M Required] In a multi-channel access (hereinafter abbreviated as MCA) communication system for mutual data communication between a center and a terminal and between terminals via a center, data collection of a terminal is performed. In order to solve the problem of only one terminal being able to access the channel even if multiple communication channels are available, we configured the system so that the same number of terminals as the number of free communication channels can be polled at the same time. This allows data from multiple terminals to be collected by polling.

C. Industrial Application Fields] The present invention enables mutual data communication between a center and each terminal or between terminals through the center, such as in two-way CATV (cable television), and utilizes all available communication channels. The present invention relates to an MCA communication method that enables data collection from multiple terminals by simultaneously polling the same number of terminals.

In recent years, two-way CATV has become one of the secondary media.
(cable television) is known. This is CATV
We add the function of sending signals from subscriber terminals to the center to our wired communication equipment, and provide home security services for crime prevention, disaster prevention, etc. in subscriber's homes, or individual programs of the subscriber's choice for a fee. This system enables various communication services in response to requests from subscriber terminals, such as pay-per-view services.

In addition, in the MCA communication system, a large number of subscriber terminals jointly use multiple communication channels for mutual data communication, and communication between subscriber terminals and a center or between subscriber terminals via a center is When a connection request to that effect occurs, this is done by allocating an empty communication channel to both parties.

However, even when collecting data from each terminal by polling, such as in an automatic meter reading service, data cannot be collected unless each terminal is called one by one and a communication channel is assigned. Therefore, it is desired that polling type communication can be performed efficiently even in the MCA communication system.

[Conventional technology]

FIG. 5 shows a configuration diagram of an MCA communication system for performing data communication within a bidirectional CATV. In the same figure, 1
is a CATV center, which includes a central processing unit (hereinafter referred to as CPU) la for data communication, an MCA communication device 1b, and a head end 1c. 2 is the head end lc above
Transmission lines such as coaxial cables and optical fiber cables connected to 31.32. ... are bidirectional branch amplifiers provided on the transmission line 2, 41, 42 . ... denotes each bidirectional branch amplifier 31, 32 . These subscribers are equipped with an MCA terminal device 4a and terminals 4b such as personal computers, televisions, security service information panels, etc. connected to the MCA terminal device 4a, and the terminals 4b and the CPU of the center 1
Data communication between Ia is between MCA communication device 1b and MCA
This is realized by the terminal device 4a.

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

FIG. 6 shows a logical image of the channel configuration of the MCA system, in which, like a mobile communication system, there is one control channel chg and multiple communication channels ch1, c,
h2. -...chm, and each of these channels cho
and chl~Chm are converter ld, headend I
It is connected to the transmission line 2 through C.

FIG. 7 is for explaining the outline of the communication procedure of the communication system configured as described above.

When data communication is to be performed between the CPU 1a of the center 1 and the terminal 4b, first, the CPU 1a of the center 1
sends a channel allocation request to the other party.

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 the communication channels and instructs the subscriber side MCA terminal device 4a to use an empty communication channel. Upon receiving this, the MCA terminal device 4a switches to the designated communication channel to enable communication between the CPU 1a of the center 1 and the terminal 4b. Also, the data communication ends and the terminal 4b
When a disconnection request is sent from the MCA terminal device 4a, the disconnection request is sent to the center side through the control channel. The center side sends a disconnection indication to the terminal side through the control channel, thereby cutting off the communication channel between the two sides.

Next, the operation when collecting data by polling terminals using the MCA communication system will be explained based on FIG. 8.

First, the center's CPU l a outputs the MCA terminal number from which data is to be collected to the center's MCA communication device lb and requests a connection. Upon receiving this connection request, the MCA communication device 1b searches for free communication channels, selects one, and designates the communication channel to the MCA terminal device 4a. At this time, the downlink data format sent from the center-side MCA communication device 1b to the subscriber-side MCA terminal device 4a through the control channel is such that the MCA terminal number has a channel assignment and a channel number code. It will be added.

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. Thereafter, the MCA communication device 1b notifies the CPU 1a of the channel connection, and at the same time, the subscriber-side MCA terminal 54a notifies the polling response terminal 4b of the channel connection. Polling is performed on the poll response terminal 4b through the poll response terminal 4b. Then, data is returned from the terminal 4b in response to the polling.

When data collection by the center CPU 1a is completed, the CPU
1a outputs a channel disconnection request to MCA communication device 1b. Upon receiving this, the MCA communication device 1b instructs the MCA terminal device 4a on the polling response terminal side to disconnect the channel through the IIJ control channel, disconnects the designated channel to the terminal, and ends the process.

In the same way, each free communication channel is sequentially set to M.
Connect to the CA terminal and poll.

[Problem that the invention seeks to solve]

When performing polling data collection using the conventional MCA communication system as described above, each terminal is sequentially called, a communication channel is assigned to each terminal, and then a communication channel is assigned to each terminal.
Since terminal data is collected through data communication, the data collection speed is slow, and even if there is an empty communication channel other than the allocated one,
You can only access one device.

In addition, if automatic meter reading service and PC communication service are performed using two-way CATV, polling equipment and M
Each of these required a CA communication device, which led to the complexity of the communication equipment.

The present invention was made to solve the above-mentioned problems, and it makes it possible to poll multiple terminals at the same time. The purpose is to provide an MCA communication method that is made possible by the same system.

[Means for solving problems]

FIG. 1 shows a block diagram of the principle of the present invention. In the figure, 10 is a center, which includes a central processing unit (hereinafter referred to as CPU) 11 for data communication, an MCA communication device 12, and a memory 13 for storing terminal numbers to be polled and communication channel numbers for polling. There is.

When polling and collecting terminal data, the CPU II issues a channel reservation request to the MCA communication device 12, and accordingly sends terminal numbers corresponding to the number of vacant communication channels searched by the MCA communication device 12 to the MCA communication device. MCA communication device 12.
has the function of searching for a currently available communication channel, securing it, and simultaneously polling each designated terminal based on the contents of the memory 13.

141.142. ... are subscribers who perform data communication with the center 10, and bidirectional branch amplifiers 151, 152,
... to the center 10 by a transmission line 16, and these subscribers are connected to an MCA terminal device 17 and a terminal connected thereto, which establish a designated channel from the center IO to enable data communication. 18, and polling response means 19 for notifying the polling terminal of connection in response to polling from the center 10.

[For production]

In the present invention, all vacant communication channels searched by the MCA communication device 12 are notified to the CPUI 1 in response to a channel reservation request from the CPUI 1, and accordingly, the CPU
When I1 notifies the MCA communication device 12 of a terminal polling request corresponding to each free channel, the MCA communication device 12 sends the specified MCA &
Polling is performed at the end of I.

The corresponding MCA terminal devices 17 receive this and switch to each specified channel all at once, take in data from the polling response terminal, and send it to the center side.

Therefore, in the present invention, by polling the same number of terminals as the number of available communication channels at the same time, it becomes possible to poll and collect data from a plurality of terminals at once.

〔Example〕

FIG. 2 shows an embodiment of the MCA communication system of the present invention.

1, the center 10 includes a CPU 1 for data communication, an MCA communication device 12, and a CPU
It has a memory 13 for recording the polling target MCA terminal number notified from I1 and the polling free communication channel number searched by the MCA communication device 12.

The MCA communication device 512 has a line control value f122 connected to c, puz via an interface 121,
A control channel transceiver 123 connected to this line control device 122 and a plurality of communication channel transceivers 1251 connected to the CPU 1 via an interface 124.
．． ...125°, and each of the above-mentioned transceivers 123 and 1
25+, ... mixer 126 connected to t25n
The mixer 126 is connected to the transmission line 16 via a node end 127. Further, a memory 13 for recording the MCA terminal number to be polled and the communication channel number for polling is connected to the line control device 122.

In addition, a bidirectional branch amplifier 151.15 is connected to the transmission line 16.
2. Subscribers 141, 142 connected via...
．． The MCA terminal devices 17 of... have bidirectional branching amplifiers 151, 152 . ... via a tap-off 171, a control response device 173 connected to this transceiver 172, and a control response device 173.
The transceiver 172 operates in response to channel satellite signals from the
The polling response means 19 has a channel switching device 174 for switching the communication channel of t to a channel in the upper room, and a terminal interface 175 for interfacing the control response device 173 with a line-switched communication terminal 18a such as a personal computer. The polling response device 191 connected to the control response device 173 and the polling response device 1
91 and polling type communication terminals 18 such as meters and sensors
and a polling terminal interface 192 that interfaces with the polling terminal interface 192.b.

FIG. 3 shows the operating procedure when collecting terminal data by polling, and the operation of this system will be explained based on this figure.

First, a request to secure a channel for use in polling is output from the center CPtJ'll to the MCA communication device 12. The line control circuit 1 of the MCA communication device 12 that received this
22 searches for a current free communication channel, secures it, records the channel number in memory as a polling communication channel, and notifies the CPUI 1 of the number of free communication channels and the channel number. C
The PtJ 11 notifies the MCA communication device 12 of MCA terminal numbers corresponding to the number of available communication channels, and
Request terminal polling. It then waits for data to be returned through each available communication channel. At this time, which communication channel is connected to which terminal is determined in advance in the order in which the MCA terminal numbers are input.

The line control device 122 on the side of the MCA communication device 12 that received the notification from the CPUI 1 records the polling target MCA terminal number in the memory 13, and stores the polling target MCA terminal number and the polling communication channel number in the memory 13. The data are sequentially read out in the order of input and combined as shown in the data format shown in FIG. 4, and a code indicating polling is added to the conventional connection channel designation part.

A signal in this data format is continuously sent from the control channel transceiver 123 to the subscriber side through a downlink control channel, and polls each designated terminal.

In the MCA terminal device 17 on the subscriber side, if the polling request corresponds to the polling request, the transceiver 172 receives the signal transmitted through the downlink control channel, and the control response device 173 that receives the received data, The specified communication channel is instructed to the channel switching device 174, and the channel switching device 174 thereby switches the communication channel of the transmitter/receiver 172 to the specified channel, causes the polling response device 191 to respond, and connects the polling terminal interface. 192 to notify the terminal 18b of the connection. Accordingly, the data output from the polling response terminal 18b is transmitted to the terminal interface 192.
Control response device 173 through polling response device 191
At the same time, it is transmitted from the transceiver 172 to the center 10 side through a designated communication channel.

On the other hand, when the data collection at the end of each MCAlf% for which polling requests are completed, the CPU II sends the MCA communication device 1
2, a channel disconnection request is issued to
Give the disconnection to the hypo, disconnect the respective communication channel, and enter the next operation.

In this way, all available communication channels are used to poll multiple terminals at once, so data collection from each terminal takes less time than when calling each terminal one by one and allocating communication channels. . Also, since the number of polling devices is changed according to the number of free communication channels,
Even if the usage status of the line changes, the operation will not be affected.
It simply changes the time it takes for all polling to finish.

In addition, for line-switched communication such as PC communication, the control response device 173 and terminal interface 17 shown in FIG.
However, this circuit-switched communication is generally used a lot from daytime to night, and polling-based communication such as one-way dynamic meter reading can be done late at night, so the line utilization rate can be more averaged. can be converted into Furthermore, the center CPU
Since the II does not need to perform detailed operations, the load on the CPU side can be reduced even if polling and contention communications are handled simultaneously.

Furthermore, although the MCA terminal requires a response means for polling, it does not require a transmitter/receiver exclusively for polling, so it is better to use the communication device part than to have a polling response terminal device and a personal computer communication terminal device separately. can be small.

Note that the method of the present invention is applicable to bidirectional CAT as shown in the embodiment.
Of course, the present invention is applicable not only to the MCA communication system within V, but also to other new media systems, communication systems, etc.

〔Effect of the invention〕

As described above, according to the MCA communication system of the present invention, it is possible to simultaneously poll the same number of terminals as the number of free communication channels by using the downlink side of the control channel for polling, and to check the availability of the communication channels. In addition to being able to automatically change the number at any time, polling that matches the line status can be performed simply by understanding the status of the communication channel on the MCA communication device side.

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 an embodiment of the invention. Control channel downlink data format in Figure 5 is a configuration diagram of a conventional MCA communication system, Figure 6 is a diagram showing a logical image of the channel configuration of the MCA method, Figure 7 is a diagram showing a communication procedure of the communication system, FIG. 8 is a diagram showing a boring procedure using a conventional MCA communication system, and FIG. 9 is a conventional control channel downlink data format. In FIGS. 1 and 2, 10 is a center, and 11 is a CPU. 12 is an MCA communication device; 13 is a memory; 141.142. ...is a subscriber, 151.152
．． ... is a bidirectional branching amplifier, 16 is a transmission line, 17 is an MCA terminal device, 18 is a terminal, and 19 is a polling response means.蓓詑鴫W Principle 0/Riff diagram 10 Figure 5 Figure B±Wataru 1. Name 1 LhH, Takumi Shiro Figure 7

Claims (1)

[Scope of Claims] A central processing unit (11) for data communication that issues a channel reservation request and a number of terminal polling requests according to the number of free communication channels during polling, and the central processing unit (11).
In response to a channel reservation request from the central processing unit (11), a vacant communication channel is searched and recorded in the memory (13), and in response to a terminal polling request from the central processing unit (11), the memory (1) is searched for.
A center (10) having an MCA communication device (12) that sequentially reads the polling target terminal number and polling communication channel number in 3) and polls the designated terminal through the control channel; The MCA terminal device (17) is connected via the MCA terminal device (16), and establishes a communication channel based on a channel instruction from the center side MCA communication device (12) to enable data communication, and also returns terminal data in response to polling. ) and the terminal connected to it (1
8) Subscribers (14_1, 14_2,...) with
A multi-channel access communication system characterized by simultaneously polling the same number of terminals as the number of free channels.