JP2001339332A - Satellite data distribution system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a satellite data distribution system that can reduce reception failure probability of satellite data so as to enhance the efficiency of a satellite channel. SOLUTION: A satellite transmission means 3 transmits data for reception confirmation to reception terminals 10, 20 at a prescribed time interval via a communication satellite 1. A satellite reception means 11 receives distributed data and stores the reception success/ failure to a reception history information management means 12. A ground channel transmission means 13 transmits the reception history information stored in the reception history information management means 12 to a center station 2 immediately after the reception of the reception history information or at a prescribed time interval through a ground channel. A ground channel reception means 6 receives a reception successful rate by each time zone collected from the reception terminals 10, 20, a time zone dependent reception successful rate collection means 5 collects the reception successful rates for each time zone, and a distribution schedule generating means 4 generates a distribution schedule concentrated for the time zone with the highest reception successful rate. The satellite transmission means 3 transmits data according to the schedule. Furthermore, a meteorological forecast information management means 7 can edit a distribution schedule that takes an area time zone dependent meteorological condition under its management into account.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a satellite data distribution system.

[0002]

2. Description of the Related Art Satellite communication is wireless communication performed by relaying an artificial satellite launched in orbit around the earth, and performs one-way data distribution from a center station (transmitting station) to a large number of receiving terminals. A satellite data distribution system is one of such satellite communications. Satellite communication has advantages such as a wide communicable area, high-speed transmission, overcoming geographical obstacles, uniform communication quality, and disaster tolerance. On the other hand, it has a disadvantage that it is easily affected by weather conditions such as rainfall and snowfall, and transmission delay time is long.

[0003] Many improved techniques have been proposed for compensating for the shortcomings of satellite communications. The `` satellite communication line backup method '' described in Japanese Patent Application Laid-Open No. 9-36790 discloses that, when a fault occurs between a slave station and a communication satellite, the faulty slave station is transmitted via another good slave station. Satellite communication is available. They make a detour on the ground line. Further, a "line switching control device of a satellite communication system" described in Japanese Patent Application Laid-Open No. 1-293020 is a host computer and a terminal that perform data communication between satellites connected to a satellite line via a satellite access device of a ground station. Is switched to a terrestrial bypass line when the satellite line is abnormal. Furthermore, the "line failure remedy method for satellite communication networks" described in JP-A-3-58632 recognizes a satellite link failure as a micro-ground station failure for satellite communication, and replaces the satellite communication form with a terrestrial public line network. I do. In addition,
No. 11-298474, `` Wide-area data distribution system using satellites '' is a receiving station whose received radio wave has dropped due to rainfall etc., and data can no longer be received from satellites,
By distributing information that associates with a receivable receiving station via a satellite, data receivable by the receivable station is transmitted to a non-receivable station using a public network.

[0004] As described above, the conventional satellite communication system includes:
Immediately before performing satellite data transmission or after confirming that data reception has failed, a drop in the satellite signal level or data non-arrival is detected, and a detour to the ground system is attempted.

[0005]

However, the first problem of the above-mentioned prior art is that the cause of communication failure is limited to weather conditions. The receiving terminal may be a dedicated device that performs only satellite reception, but may also have a function of distributing received data and performing post-processing in addition to satellite reception.
When the terminal function for providing services for the user and the satellite reception function are implemented in the same device, it is necessary to add these functions to the cause of communication failure. That is, when performing processing other than satellite reception, the processing capacity of the receiving terminal temporarily decreases due to the processing load other than satellite reception,
This is because the receiving terminal may fail to receive satellite data or the data may take a long time to reach the receiving terminal.

A second problem is that a satellite data communication failure can be detected only after the fact. If after confirming that the data distribution has failed, then detouring the satellite transmission to the terrestrial system after the fact, it is not possible to guarantee that the data will reach all the terminals within the expected time. The arrival time will be greatly delayed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and a first object of the present invention is to reduce the probability of reception failure in satellite data distribution and to improve the efficiency of satellite line utilization. Is to provide.

A second object of the present invention is to provide a satellite data distribution system capable of shortening the data arrival time.

[0009]

According to a first aspect of the present invention, there is provided a satellite data distribution system for distributing data from a center station to at least one receiving terminal via a communication satellite. A time schedule for data distribution from the center station to the receiving terminal is created based on a reception success rate of the reception terminal for the reception confirmation data transmitted from the center station for each time zone.

According to a second aspect of the present invention, there is provided a satellite data distribution system for distributing data from a center station (2) to at least one receiving terminal (10, 20) via a communication satellite (1). The receiving terminal (10, 20) is the center station (2)
Satellite receiving means (11, 21) for receiving data distributed from
If the received data is data for reception confirmation, reception history information management means (12, 22) for storing the success or failure of the reception
And ground line transmitting means (13, 23) for transmitting the reception history information stored in the reception history information management means (12, 22) to the center station (2) via the ground line immediately or at fixed time intervals. The center station (2) has a receiving terminal via a communication satellite (1).
Toward (10, 20), data for reception confirmation at regular time intervals,
Or a satellite transmitting means (3) for transmitting data intended for original distribution, and a terrestrial line receiving means (6) for receiving, from the receiving terminals (10, 20), reception history information collected for data for reception confirmation. And a time zone-based reception success rate totaling means for totalizing the reception success rate for each time zone based on the received reception history information
(5) and the distribution schedule concentrated in the time zone with the highest reception success rate based on the reception success rate by time period tabulated by the reception success rate totaling means by time period (5) for each receiving terminal (10, 20) And a delivery schedule creating means (4) for creating the data, and the satellite transmitting means (3) transmits the original data for delivery in accordance with the schedule.

A third aspect of the present invention is a satellite data distribution system for distributing data from a center station (2) to at least one receiving terminal (10, 20) via a communication satellite (1). The receiving terminal (10, 20) is the center station (2)
Satellite receiving means (11, 21) for receiving data distributed from
If the received data is data for reception confirmation, reception history information management means (12, 22) for storing the success or failure of the reception
And ground line transmitting means (13, 23) for transmitting the reception history information stored in the reception history information management means (12, 22) to the center station (2) via the ground line immediately or at fixed time intervals. The center station (2) has a receiving terminal via a communication satellite (1).
Toward (10, 20), data for reception confirmation at regular time intervals,
Or a satellite transmitting means (3) for transmitting data intended for original distribution, and a terrestrial line receiving means (6) for receiving, from the receiving terminals (10, 20), reception history information collected for data for reception confirmation. And a time zone-based reception success rate totaling means for totalizing the reception success rate for each time zone based on the received reception history information
(5) and weather forecast information management means for managing weather forecast information
(7) and the time of the highest reception success rate based on the time-of-day reception success rate and the weather forecast information managed by the weather forecast information management means (7) compiled by the time-of-day reception success rate aggregation means (5). Distribution schedule creating means (4) for creating a distribution schedule concentrated on the band for each receiving terminal (10, 20), and the satellite transmitting means (3) transmits data intended for original distribution in accordance with this schedule. Features.

According to the present invention, in a data distribution system using a communication satellite, data reception success rate information for each time zone collected from a receiving terminal, or data reception success rate information and weather forecast information acquired from a weather forecasting organization are used. Furthermore, by scheduling the distribution time so that the reception success rate on the receiving terminal side is the highest, efficient satellite data distribution to a large number of receiving terminals is enabled.

According to the present invention, in a satellite data distribution method for distributing data from a center station to at least one receiving terminal via a communication satellite, first, a center station is directed to a receiving terminal via a communication satellite at regular time intervals. The reception confirmation data is transmitted. The receiving terminal receives the data for reception confirmation distributed from the center station, and stores the success or failure of the received data for reception confirmation. The stored reception history information of the reception success or failure is transmitted to the center station immediately or at a fixed time interval by a ground line. The center station receives this, and totalizes the reception success rate for each time zone based on the received reception history information. Then, a distribution schedule concentrated on the time zone having the highest reception success rate is created for each receiving terminal based on the tabulated reception success rates for each time zone, and the original distribution target data is transmitted according to the distribution schedule. When creating a distribution schedule, weather conditions may be taken into account.

According to the present invention, the data delivery time is scheduled in a time zone in which the data reception success rate is highest at the receiving terminal based on the predicted reception success rate. Enables distribution and transmission with proper line usage time. Also, in satellite data distribution, a method of transmitting the same data a plurality of times to increase the overall reception success rate is known. In such a case, according to the distribution scheduling method based on the expected reception success rate of the present invention, by distributing the distribution time so that the same file is not repeatedly transmitted in a time zone with a low reception success rate, Thus, even if the reception success rates are the same, the overall reception success rate can be increased.

[0015]

Next, embodiments of the present invention will be described with reference to the drawings.

Referring to FIG. 1, one embodiment of the satellite data distribution system of the present invention is a communication satellite 1, a center station 2 as a transmitting station for distributing satellite data, and two receiving terminals 1
It consists of 0 and 20. The communication satellite 1 is a geostationary satellite launched in an orbit above the equator. Center station 2 is receiving terminal 1
The data is distributed to communication channels 0 and 20 via the communication satellite 1.
For example, the receiving terminals 10 and 20 may be installed at about several places like an office, or may be installed at 10,000 places or more like a convenience store or a gas station nationwide. The receiving terminals 10 and 20 perform distribution of received data and post-processing in addition to the processing of receiving data from the communication satellite 1.

FIG. 1 shows two receiving terminals 10 and 20, but since they have the same configuration, the receiving terminal 10 will be described below. The receiving terminal 10 includes, in addition to the satellite receiving means 11 for receiving data from the communication satellite 1, a receiving history information managing means 12 for managing receiving history information, and a terrestrial transmitting the receiving history information to the center station 2 via a terrestrial line. It is composed of line transmission means 13.

The center station 2 receives, in addition to the satellite transmitting means 3 for transmitting data to the communication satellite 1, the weather forecast information managing means 7 for managing weather forecast information, and reception history information from the receiving terminals 10 and 20. The terrestrial line receiving means 6, the time-based reception success rate totaling means 5 for counting received reception history information, and the weather forecast information managed by the weather forecast information management means 7 and the time calculated by the hourly reception success rate counting means 5 Distribution schedule creation means 4 for creating a schedule of distribution data from the reception success rate.

Each of these means operates as follows. First, the satellite transmitting means 3 of the center station 2 transmits data for reception confirmation or data intended for distribution at regular time intervals to the receiving terminals 10 and 20 via the communication satellite 1. The satellite receiving means 11 of the receiving terminal 10 receives the distributed data and, if the data is data for confirming reception, stores the success or failure of the reception in the reception history information management means 12. The terrestrial line transmission means 13 transmits the reception history information stored in the reception history information means 12 to the center station 2 immediately after reception or via a terrestrial line at fixed time intervals. If the received data is originally intended, the receiving terminal 10 performs distribution and post-processing of the data. The ground line transmission means 13
It also serves as a general means of communication with the center station 2 using a ground line. FIG. 1 shows the receiving terminal 10 in this regard.
Although only a route in the direction from the center station 2 is shown, a route in the opposite direction is actually provided.

The terrestrial line receiving means 6 of the center station 2 receives, from the receiving terminals 10 and 20, the reception history information collected for the data for confirming reception. Receiving success rate totaling means by time zone
5 tabulates the reception success rate for each time zone based on the reception history information. FIG. 2 shows an example of the reception success rate for each time period, which is calculated by the reception success rate totaling means for each time period 5 based on the reception history information transmitted from the receiving terminals 10 and 20.
In this example, since the receiving terminal 10 performs the batch processing from midnight to early morning, the reception probability in the time zone from 00:00 to 6:00 is particularly low, and the reception probability is high in the afternoon to night.

The distribution schedule creating means 4 divides the distribution schedule concentrated in the time zone having the highest reception success rate into the receiving terminals 10 and 20 based on the reception success rate for each time zone.
Create for each. The satellite transmitting means 3 transmits data according to the schedule.

Next, by creating a distribution schedule that takes into account not only the reception success rate for each time zone but also the weather forecast information for each area and time zone managed by the weather forecast information management means 7, more efficient delivery is performed. Enables creation of schedules. It takes into account weather conditions, which can be called the fate of satellite communications. In the case of fine weather, there is no effect on reception, but the reception probability decreases in the case of rainfall, and the influence on reception is large particularly in the case of heavy rain such as in a thunderstorm. FIG. 3 shows an example of weather forecast information for each area and time zone managed by the weather forecast information management means 7.

The center station 2 holds information on the area where the receiving terminals 10 and 20 are installed. FIG. 4 shows an example of such information as a terminal installation location list. FIG.
Although two receiving terminals 10 and 20 are shown, three receiving terminals A, B, and C are used here to increase the number of cases. The distribution schedule creation means 4 combines the weather forecast information for each area and time zone in FIG. 3 with the terminal installation location list in FIG. 4 to create reception terminal weather information as shown in FIG.

Now, the center station 2 transmits the distribution data 1 to the receiving terminal A, the distribution data 2 to the receiving terminal B, and the distribution data 3 to the receiving terminal C, and uses the same distribution data to increase the receiving probability. Is transmitted twice each time. Under such a distribution plan, the distribution schedule creating means 4 refers to the reception success rates by time period in FIG. 2 and the reception terminal weather information in FIG.
Create a distribution schedule for each. First, avoid the rainy time zone and select the one with the higher reception probability during the sunny time zone. For example, in the area of the receiving terminal A, as is clear from FIG. 5, there are three sunny time zones. Is transmitted, and then the second distribution data # 2 is transmitted at 12: 00-18: 00.

FIG. 7 shows a schematic flow in the case where a distribution schedule is created in consideration of the above-mentioned reception success rate and weather forecast information for each area and time zone. Further, with reference to the flowchart of FIG. 8, the operation in the case of creating a distribution schedule in this embodiment will be described in detail.

First, the reception confirmation data is distributed from the center station 2 to the receiving terminals 10 and 20 at fixed time intervals by satellite (step 101 in FIG. 2). Next, reception success / failure information at the receiving terminals 10 and 20 is collected (step 102 in FIG. 2), and a reception success rate for each time zone is calculated from the information (step 102 in FIG. 2).
103). Further, weather forecast information for each time zone for which a distribution schedule is to be obtained from the weather forecasting organization (step in FIG. 2).
104), taking into account this information, the expected reception success probability in the distribution schedule target time zone is calculated and obtained (step 105 in FIG. 2).

In the satellite data distribution, a method of repeatedly transmitting the same data is often adopted in order to increase the data reception success rate. If there is no repetition,
Delivery data is scheduled sequentially from a time zone having a high reception success rate (step 107). The same applies to the case where repetitive transmission is performed. However, a schedule is created so that the same data is not repeatedly delivered in a time zone with a low reception success rate (step 108). This eliminates the waste of repeatedly transmitting the same file during a time period when the reception success rate is low.

A program for causing a computer to execute the satellite data distribution method described above is stored in a semiconductor memory, a floppy (registered trademark) disk, a CD-RO.
Alternatively, the program may be recorded on a recording medium such as M, read by a computer, and executed. Among these programs, the program loaded into the center station 2 controls a computer constituting the center station 2, and transmits the computer to the satellite transmitting means 3, the distribution schedule creating means 4, the reception success rate totaling means by time zone 5 , And functions as a terrestrial line receiving means 6 and a weather forecast information managing means 7. The program loaded into the receiving terminal 10 in the program causes the receiving terminal 10 to function as the satellite receiving means 10, the reception history information managing means 12, and the terrestrial line transmitting means 13.

[0029]

The first effect of the present invention is that the probability of satellite data distribution reception failure can be reduced, and the utilization efficiency of satellite links can be increased. The reason is that the distribution schedule was created using the reception success rate information for each time zone collected from the receiving terminal or taking into account the weather forecast information. This is because it is possible to avoid a time zone in which the failure probability is high. If the method of repeatedly delivering the same data is adopted, by distributing the delivery schedule so that the same data is not repeatedly delivered during the time period when the reception success rate is low, the Even so,
It is possible to increase the overall reception success rate.

A second effect of the present invention is that the time required for data arrival can be reduced. When data distribution using a satellite fails, there is known a method for guaranteeing data arrival by performing retransmission using a satellite or retransmission by switching to a terrestrial line and using another route. But,
Extra time is required until retransmission is completed. According to the present invention, if it is necessary to distribute in advance in a time zone with a high reception success probability or to transmit in a time zone with a low success rate, it is possible to switch to another transmission means at an early stage. This is because the data arrival time can be shortened.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing an example of a reception success rate for each time zone used in the present invention.

FIG. 3 is a diagram showing an example of weather forecast information by region and time zone used in the present invention.

FIG. 4 is a diagram showing an example of a terminal installation location list used in the present invention.

FIG. 5 is a diagram showing an example of receiving terminal weather information created in the present invention.

FIG. 6 is a diagram showing an example of a data distribution schedule created in the present invention.

FIG. 7 is a schematic flowchart for creating a distribution schedule according to the present invention.

FIG. 8 is a detailed flowchart for creating a distribution schedule according to the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 communication satellite 2 center station 3 satellite transmission means 4 distribution schedule creation means 5 reception success rate totaling means by time zone 6 terrestrial line reception means 7 weather forecast information management means 20 receiving terminal 21 satellite reception means 22 reception history information management means 23 terrestrial Line transmitting means 30 receiving terminal 31 satellite receiving means 32 receiving history information managing means 33 terrestrial line transmitting means

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) H04L 29/08

Claims (7)

[Claims] 1. A satellite data distribution system for distributing data from a center station to at least one receiving terminal via a communication satellite, wherein said receiving terminal responds to reception confirmation data transmitted from said center station at regular time intervals. A satellite data distribution system, wherein a time schedule for data distribution from the center station to the receiving terminal is created based on a reception success rate for each time zone. 2. A satellite data distribution system for distributing data from a center station to at least one receiving terminal via a communication satellite, wherein each of the receiving terminals includes: satellite receiving means for receiving data distributed from the center station; If the received data is reception confirmation data, the reception history information management means for storing the success or failure of the reception, and the reception history information stored in the reception history information management means can be transmitted immediately or at fixed time intervals to the ground line. Terrestrial line transmitting means for transmitting to the center station by way of the center station, wherein the center station directs the data to the receiving terminal via the communication satellite at regular time intervals for the reception confirmation data or the original data for the purpose of distribution. Satellite transmission means for transmitting the reception history information collected for the reception confirmation data from the reception terminal. Means, time-based reception success rate totalizing means for totalizing the reception success rate for each time zone based on the received reception history information, and time zone reception success rate calculated by the time-zone reception success rate totaling means Distribution schedule creation means for creating, for each of the receiving terminals, a distribution schedule concentrated in a time zone having the highest reception success rate based on the above, and the satellite transmission means transmits the original data for distribution purpose according to the schedule. A satellite data distribution system, characterized in that: 3. A satellite data distribution system for distributing data from a center station to at least one receiving terminal via a communication satellite, wherein each of the receiving terminals includes: satellite receiving means for receiving data distributed from the center station; If the received data is reception confirmation data, the reception history information management means for storing the success or failure of the reception, and the reception history information stored in the reception history information management means can be transmitted immediately or at fixed time intervals to the ground line. Terrestrial line transmitting means for transmitting to the center station by way of the center station, wherein the center station directs the data to the receiving terminal via the communication satellite at regular time intervals for the reception confirmation data or the original data for the purpose of distribution. Satellite transmission means for transmitting the reception history information collected for the reception confirmation data from the reception terminal. Time-based reception success rate totalizing means for totalizing a reception success rate for each time zone based on the received reception history information; weather forecast information management means for managing weather forecast information; Distribution that creates a distribution schedule concentrated on the time zone with the highest reception success rate for each of the receiving terminals based on the reception success rate for each time zone counted by the rate aggregation means and the weather forecast information managed by the weather forecast information management means. A satellite data distribution system, comprising: schedule creation means; wherein the satellite transmission means transmits the original data for distribution in accordance with the schedule. 4. When the same data is transmitted a plurality of times, the distribution schedule creating means distributes the distribution time so that the same file is not repeatedly transmitted in a time zone with a low reception success rate. The satellite data distribution system according to claim 2 or 3, wherein: 5. A satellite data distribution method for distributing data from a center station to at least one receiving terminal via a communication satellite, wherein the satellite data is transmitted from the center station to the receiving terminal via the communication satellite at regular time intervals. A first procedure for transmitting reception confirmation data, a second procedure for receiving the reception confirmation data distributed from the center station to the reception terminal, and storing the success or failure of the received reception confirmation data. A third procedure, a fourth procedure for transmitting the stored reception history information of the reception success or failure immediately or at a fixed time interval to the center station via a terrestrial line; and collecting the reception confirmation data. A fifth procedure of receiving the reception history information from the receiving terminal, a sixth procedure of totalizing a reception success rate for each time zone based on the received reception history information, A seventh procedure for creating, for each of the receiving terminals, a distribution schedule concentrated on the time zone having the highest reception success rate based on the reception success rate for each time zone, and transmitting the original data for distribution purpose according to the distribution schedule. A satellite data distribution method characterized by eight procedures. 6. A satellite data distribution method for distributing data from a center station to at least one receiving terminal via a communication satellite, wherein the satellite data is transmitted from the center station to the receiving terminal via the communication satellite at regular time intervals. A first procedure for transmitting reception confirmation data, a second procedure for receiving the reception confirmation data distributed from the center station to the reception terminal, and storing the success or failure of the received reception confirmation data. A third procedure, a fourth procedure for transmitting the stored reception history information of the reception success or failure immediately or at a fixed time interval to the center station via a terrestrial line; and collecting the reception confirmation data. A fifth procedure for receiving the reception history information from the receiving terminal, a sixth procedure for totalizing a reception success rate for each time zone based on the received reception history information, A seventh procedure for managing the broadcast information, and a distribution schedule concentrated on the time zone having the highest reception success rate based on the totaled time zone reception success rate and the managed weather forecast information for each of the receiving terminals. A satellite data distribution method, comprising: an eighth procedure for creating; and a ninth procedure for transmitting data intended for distribution in accordance with the distribution schedule. 7. A computer that constitutes a center station executes the first and fifth to eighth procedures according to claim 5 or the first and fifth to ninth procedures according to claim 6, and A computer-readable recording medium recording a program for causing a receiving terminal to execute the second to fourth procedures according to claim 5 or 6.