JP2667865B2 - Broadcast communication system control method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a control method for a broadcast communication system, and a target child satisfying a request of a user (application) of a broadcast information transmitting station (master station). The present invention relates to a control method of a broadcast communication system suitable for station setting.

[Conventional technology]

Conventional broadcast control methods in the field of wireless communication include:
As described in Japanese Patent Application Laid-Open No. 60-85631, a method in which broadcast information is transmitted only unilaterally from a transmitting station to a receiving station and response information from the receiving station to the transmitting station is not transmitted is adopted. Is common. Therefore, this conventional method is a method in which a broadcast information transmitting station unilaterally transmits information without grasping a receiving station.

In the method described in Japanese Patent Application Laid-Open No. 61-150450, each receiving terminal receives only necessary information, notifies the information provider of the type of required information by using a keyword, and the information provider requires information. Sent only to the recipient, the information provider can know from the unspecified number of receiving terminals the receiving terminals that need the information indicated by the specific keyword,
This is a method in which an information provider can actively receive whether or not he or she has the necessary information and receive the information.

[Problems to be solved by the invention]

As shown in the above prior art, when a response is not required in the conventional broadcast communication system, a slave station to be communicated is not known. In a broadcast communication system that does not require a response, since the information provider (master station) does not know the target receiving station, all slave stations receive information on the slave station regardless of the content. There was a problem.

In the communication system requiring the response of the above-mentioned prior art,
The information provider recognizes the receiving terminal in response to the information request from the receiving terminal, and does not consider the recognition and setting of the receiving station according to the information provider's request in the broadcast communication. In general, in the field of data communication, a method of taking a response to ensure reliability is used, but in broadcast communication, there are a plurality of slave stations which need to take a response, and a method of recognizing this is a problem.

Accordingly, an object of the present invention is to provide a broadcast communication system in which when a master station establishes a link (line) with a slave station, the master station identifies the target slave station by a response frame from each slave station to a link setting frame. Then, it is to set the slave station that satisfies the request of the user of the master station.

[Means for solving the problem]

The present invention is a means for transmitting a plurality of link setting frames by time-out control in order to perform a link setting with a slave station that satisfies a user's request of a master station, and a group that enables a slave station to belong to a plurality of groups. This is achieved by means for establishing a link corresponding to a group corresponding to the group, and means for notifying the user of the master station when the setting of the slave station according to the request of the user of the master station is impossible.

[Action]

When the master station establishes a link with the slave station, it recognizes the response frame from each slave station to the link setting frame to grasp the target slave station from the master station in the broadcast communication, and the user of the master station It is possible to set up slave stations that satisfy the requirements of.

The master station transmits a link setting frame by means of transmitting a plurality of link setting frames, and starts a timer at this time. Each slave station transmits a response frame in response to this link setup frame. The master station continues to receive the response frame until the timeout occurs, and stores the response frame reception from the slave station in a table for managing the slave station, and stores the table. It is determined whether the request from the user (application) is satisfied. If the request is not satisfied, the link setting frame is transmitted again by timeout control. The master station repeats this sequence a fixed number of times. By means of grouping that makes it possible for slave stations to belong to multiple groups and link setting for groups, the master station sets this group address in the address part of the frame when transmitting information to a specific slave station. And transmits a link setting frame. Each slave station recognizes that the information assigned to itself is transmitted from the address portion of the link setting, and transmits a response frame. When it is impossible to set the slave station according to the request of the master station user, the means for notifying the master user of the reason enables the master station to recognize the operation state of each slave station, and is notified. Depending on the contents, the user (application) can determine whether to reset the link or stop the communication.

〔Example〕

Hereinafter, an embodiment of the present invention will be described with reference to the drawings, taking a satellite broadcast communication system using satellites as an example. FIG. 1 is composed of a satellite 1-1 and an earth station 1-i (i = 2 to 7). As shown in FIG. 2, each earth station 1-i (i = 2 to 7) includes a transmission / reception device 2-1 and a computer 2-2.
The computer 2-2 includes a communication control unit 2-3 and an application unit 2-4. In FIG. 1, the earth station 1-2
Is the master station, and transmits the broadcast information frame created by the computer 2-2 via the transmission / reception device 2-1. Earth station 1-3,4,
5, 6 and 7 are transmitting / receiving devices 2 for transmitting the broadcast information frame from the master station.
-1, the computer 2-2 creates a response frame to the broadcast information frame in the computer 2-2, and transmits the frame through the transmission / reception device. Here, for simplification of explanation, it is assumed that the number of slave stations is five. Further, each slave station is grouped into two groups, a group 1 (1-8) and a group 2 (1-9), and control on a group basis is enabled in the master station.

In a data communication system, a link (line) is generally set before transmitting an information frame. In a broadcast communication system, a link is set in the same manner, but at this time, a response is generally received from a receiving station in data communication. For this reason, in 1: N communication such as broadcast communication, it is necessary for the master station to know the slave station to be communicated with in order to perform response control. In FIG. 1, 1-10 indicates a link setting frame from the master station to each slave station, and 1-11 indicates a response frame from the slave station to the link setting frame.

In broadcast communication, there are a plurality of stations to be communicated, and at the request of the user (application) of the master station, (1) information desired to be received by all slave stations (2) information received only by a specific slave station Desired information (3) Information desired to be received by a certain number of slave stations out of the total number of slave stations (4) Information that only the station desired to receive should receive. It is necessary for the communication control unit 2-3 to deal with these user (application) requests by specifying the target station and grasping the number of target slave stations when setting the link.

Fig. 2 is a block diagram of the earth station.
-2, the data created by the application unit 2-4 inside is passed to the communication control unit 2-3 and transmitted via the transmission / reception device 2-1. At the time of link setting, the master station instructs the communication control unit 2-3 with a threshold value of the number of slave stations to be communicated (described later) or the address of the target station by the application. In the case of the slave station, the broadcast information is received via the transmission / reception device 2-1, and is passed to the application unit 2-4 by the communication control unit 2-3. The communication control unit 2-3 creates a response frame for the frame transmitted from the master station, and transmits the response frame via the transmission / reception device 2-1.

Next, a method of setting a link from the master station 1-2 to each of the slave stations 1-3, 4, 5, 6, and 7 for each request of the user (application) will be described with reference to FIG.

(1) Information desired to be received by all slave stations FIG. 3 is a link setting sequence diagram when information is desired to be received by all slave stations. The master station 1-2 sends a link setting frame 2-1 to each of the slave stations 1-3, 4, 5, 6, and 7. In the address portion in the link setting frame, an address (global address) enabling any station to receive is set. At this time, the master station 1-2 sets a timer for a link setting frame with a time t slightly longer than twice the propagation delay time, and monitors a timeout.

The link setting frame 2-1 is received by the slave stations 1-3, 4, 5, and 6, and these slave stations transmit a response frame 2-2 to the link setting frame to the master station 1-2. Slave station 1-7
Cannot receive a link setting frame and thus cannot send a response frame, and when a time-out occurs in the parent station 1-2, only 4 out of 5 target slave stations can obtain a response. Therefore, the timer is set again and the link setting frame 2-3 is transmitted from the master station. Next, when a timeout occurs, the link setting with all the slave stations can be performed by the response frame 2-4 from the slave station 1-7. 2
In response to the first link setting frame 2-3, only the slave station 1-7 is monitored, and for the other slave stations, the response frame 2-2 is set to the master station 1- 1 in the first link setting.
2 is receiving and is not involved.

When the slave station 1-7 does not transmit the response frame again in the second link setting, the link setting is performed again. At this time, a value n which is the number of timeouts is provided in advance, and the link setting sequence is repeated. When the number of timeouts reaches n, only 4 out of 5 stations can receive a response frame to the user (application) of the master station. The master station user communicates with the four stations, or decides to stop the communication because all the slave stations cannot receive the communication, and restart the communication after a fixed time. When the target station is set to four stations and the communication is performed again, this is notified to the communication control unit 2-3 and communication is started.

(2) Information desired to be received only by a specific slave station In the case of specific information, a target slave station is also limited, and a link is set only to the specific slave station. At this time, specific slave stations are grouped, and the group address is set in the address portion of the link setting frame and transmitted. In FIG. 1, 1-8 and 1-9 show examples of this grouping. Group 1 (1-8) consists of slave stations 1-3,4, and group 2 (1-9) consists of slave stations 1-5,6,7. By providing a plurality of these grouping patterns, it is possible to establish a link for each group. As an example, in addition to groups 1 and 2, slave stations 1-4 and 5 are registered as group 3 in each station and used as addresses when a link to a specific slave station is set. The subsequent link setting sequence is the same as the above (1).

(3) Information desired to be received by slave stations equal to or greater than a certain fixed number out of the total number of slave stations In the case of this setting method, the target of the link setting by the master station user (application) is the number of target slave stations. The communication control unit 2-3 of the number of slave stations is instructed, and the communication control unit 2-3 transmits data when a response frame to the link setting frame is received from the threshold number or more out of the total number of slave stations by this threshold value. To start. When the threshold is set to all stations, the procedure is the same as in (1) above. The link setting sequence is
Same as (1) above.

(4) Information that only the station that wants to receive should receive the information The master station does not specify the target slave station. Only the station that wants to receive the slave station transmits a response frame to the link setting frame, and the master station sends the response frame to the master station. Notify that the station is targeted. The link setting sequence is the same as the above (1).

FIG. 4 shows a control method in the master station that realizes the above-described lenko setting sequence. In box 3-1, the master station user (application) sends the above (1) to (4).
According to the request, the threshold of the number of target slave stations and the address designation of the target slave stations are performed. In accordance with this designation, a frame for link setting is transmitted at box 3-2. At this time, Box 3-3
Start a timer for time-out judgment at.

Next, a box 3-4 receives the response frame.
The received frame is registered in the slave station management table at box 3-5. The slave station management table will be described later.
Box 3-6 compares the number of set slave stations with the number of received replies, or determines whether the request from the master station user (application), such as whether all the replies of the designated address station have been received, is satisfied. If so, the box 3-10 ends the link setting and starts data transmission.

After the judgment is made in box 3-6, the time-out is judged in box 3-7. If no time-out has occurred, the process returns to box 3-4 to receive the response frame. If a time-out occurs, the number of times-out is determined in box 3-8. If the number of times-out has not been reached, the process returns to box 3-2 to retransmit the link setting frame. If the number of times of timeout has been reached, the reason for the inability to set a link is notified to the master station user in box 3-9, and the master station user issues an instruction such as link resetting.

FIG. 5 shows a slave station management table. A master station management table shown in FIG. 5 is provided in the master station, and a flag is set to 4-3 to 7 every time a response frame to the link setting is received. Reference numerals 4-3 to 7 denote feeds indicating a response frame reception state from the slave station to the link setting frame in the master station. In the case of the link setting sequence of FIG. 5, when a response frame to the link setting frame is received from the slave stations 1-3, 4, 5, and 6 at the time of the first link setting sequence, the slave station management table 4-1 The flag is set to 4-3 to 4-6. Next, when a response frame is received from the slave station 1-7 at the time of the second link setting, a flag is set in 4-7 of the slave station management table 4-1. At this point, the master station is slave station 1.
-Understand that 3 to 7 are communication target stations. By using this table, it becomes possible for the master station to grasp the target slave station, to control the link setting, and to perform response control and retransmission control during data transfer.

According to the present embodiment, the target station can be set according to the user's request in the broadcast communication system by knowing the slave station that can operate when setting the link in the master station and setting the target slave station. Becomes Further, by grasping the slave stations that have become inoperable at the time of link setting, it becomes possible to transmit data to those slave stations after data transfer to the operable stations.
In some cases, the response frame to the link setting cannot be transmitted because the power supply or the like of the target slave station is not operating, and by notifying the master station user of the slave station that cannot set the link,
It becomes possible for the parent station to warn the child station by using a telephone line or the like.

〔The invention's effect〕

According to the present invention, when setting the link from the master station to the slave station in the broadcast communication, even if the target slave station of the communication of the master station is different depending on the type of data, the request of the user of the master station is made. It is possible to set the target station that satisfies the above condition.

In data communication, a method of taking a response is used to ensure reliability. In broadcast communication, since it is a one-to-N communication, it is necessary to know a target slave station in order to perform response control, and this can be easily performed.

[Brief description of the drawings]

FIG. 1 is a block diagram of a broadcast communication system using satellites.
FIG. 3 is a block diagram showing the configuration of the earth station, FIG. 3 is a transmission sequence diagram of one embodiment of the present invention, FIG. 4 is a processing sequence diagram of a control method in the master station, and FIG. It is an explanatory view of a slave station management table. 1-1 ... satellite, 2-7 ... earth station, 1-8 ... group, 1-9 ... group 2, 1-10 ... link setting frame, 1-11 ... response frame, 2-1 ... Transceiving device, 2-2 Computer, 2-3 Communication control unit, 2-4
…… Application section, 5-1 …… Slave station management table.

Continuing from the front page (72) Inventor Nobuyuki Fujikura 1099 Ozenji Temple, Aso-ku, Kawasaki City, Kanagawa Prefecture Inside the Hitachi, Ltd. System Development Laboratory Co., Ltd. In-company (72) Inventor Ryoichi Sasaki 1099 Ozenji Temple, Aso-ku, Kawasaki City, Kanagawa Prefecture In-house System Development Laboratory, Hitachi, Ltd. (56) References JP-A-62-183638 (JP, A) JP-A-63-279633 ( JP, A) JP-A-63-129743 (JP, A) JP-A-52-155904 (JP, A) JP-A-49-95504 (JP, A)

Claims (3)

(57) [Claims] 1. A method of controlling a broadcast communication system comprising a master station transmitting broadcast information and a plurality of slave stations receiving the broadcast information, wherein a user of the master station is a communication target child. Set the threshold of the number of stations, specify this to the communication control unit at the time of link setting, send the link setting frame to the slave station, monitor the response frame to the link setting frame from the slave station above the threshold, If no response is received from a certain number of slave stations, repeat the link setting sequence a predetermined number of times,
When the link cannot be set, the user of the master station is notified of the link-unsettable station, the link is set again according to the user's instruction, and when the link can be set, data transmission is started. A method for controlling a broadcast communication system, which is characterized in that: 2. A control method for a broadcast communication system according to claim 1, wherein the grouping is performed so that the slave stations can belong to a plurality of groups, and the master station is a communication target. A method of controlling a broadcast communication system, characterized in that a link is established corresponding to a group of slave stations by setting and transmitting a group address of a group of slave stations in the link setting frame. 3. A control method for a broadcast communication system according to claim 1, wherein only a slave station that wants to receive a link setting frame from the master station transmits a response frame to the master station, and the master station transmits the response frame. A method of controlling a broadcast communication system, characterized in that only a slave station that has transmitted the response frame in the station is a communication target.