JPH11298474A - Broad area data distribution system utilizing satellite - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely receive data through a backup channel in the case a received radio wave is diminished due to rainfall or the like and data from a satellite cannot be received. SOLUTION: The data distribution system comprises a data transmission station 5, a satellite 6, and pluralities of reception stations 31A1-31An, 31B1-31Bm each consisting of an antenna and a receiver receiving a radio wave (data) from the satellite 6. The system is also provided with a public channel network by which communication is attained among optional reception stations 31A1-31An, 31B1-31Bm and with a center 34 connecting with the public channel network 33, The system distributes information that denotes cross reference between a reception station which is unable to receive temporarily data from the satellite 6 due to rainfall or the like and a reception station which is able to receive the data through the satellite 6, then the receptible station sends the received data to the reception disable station by using the public channel network.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for distributing multi-channel data to a large number of receiving stations via satellites.
Regarding a wide area data distribution system using satellites,
The present invention relates to a backup control function and a wide-area data distribution system using a satellite provided with a line when a reception failure or a non-reception situation occurs locally at some of the receiving stations due to rainfall or the like.

[0002]

2. Description of the Related Art In a data distribution system using satellites, if there is rainfall, snowfall, or the like, the signal level of a received radio wave is extremely lowered, and a data reception failure or a failure to receive data occurs. This poor data reception or inability to receive data usually lasts for a long time of several hours or more, and is one of the serious problems in a wide area data distribution system using satellites. Therefore, various proposals have conventionally been made as this measure.

[0003] Among them, the simplest solution is to (1) increase the transmission power on the satellite side in order to keep the level of the received radio wave at a sufficient level even in rainfall, (2)
There are measures such as increasing the diameter of the receiving antenna.

[0004] However, the problem (1) relates to the performance of the satellite, and it is difficult to take an immediate countermeasure, and there is also a problem of radio wave interference between satellites. In the case (2), since the diameter becomes large, a problem of an installation place and an installation method occurs.

[0005] (3) There is also a countermeasure to lower the data rate without changing the level of the received radio wave. However, since it involves changing the communication system, it cannot be easily adopted. In addition, since it is difficult to predict the degree of rainfall, this measure (3) also requires a large margin to be set, resulting in increased waste in terms of cost and the like.

Therefore, as another method, a data retransmission method has been proposed. Typical of the conventional data retransmission methods are a cyclic delivery method that interpolates missing data by periodically circulating and transmitting data,
There is known a data retransmission request method in which when a receiving side detects a data loss, it informs the transmitting station of the data loss and retransmits the missing portion, thereby interpolating the loss of the received data.

However, in these conventional data retransmission methods, in the case of the cyclic delivery method, a time corresponding to the cycle is required, and in the case of the missing data retransmission request method, retransmission data is received after a request is made. The time until
This is necessary as an interpolation time for missing data, and there is a problem that real-time data is lacking. A more fundamental problem is that, unless rainfall is strong and unreceivable, no retransmitted data can be received during that period.

In order to solve this problem, as shown in JP-A-3-58632, JP-A-9-36790 and JP-A-9-64801, each receiving station is provided with a satellite link. Is provided with a line switching device that switches to the ground line to another receiving station, and the master station or each receiving station checks the radio wave condition of the satellite line, and if necessary,
A backup method using a terrestrial line has been proposed, which controls the line switching device, switches the line, and receives data from the other new songs via the terrestrial line.

[0009] However, the above-mentioned conventional backup method using a terrestrial line can only switch to a predetermined partner, so that the probability of successful backup is low and is not suitable for a wide area distribution system.

[0010] Furthermore, the above-mentioned conventional backup method using a terrestrial line uses the terrestrial line because both the switching control of the receiving station and the transmission of data after the switching are performed through the terrestrial line. There was a problem that the burden on the user became heavy.

[0011]

SUMMARY OF THE INVENTION An object of the present invention is to provide a data distribution system which solves the above-mentioned problems of the prior art.

[0012] A more specific object of the present invention is to allow a receiving station, which has become temporarily unreceivable due to rainfall or the like, to transmit received data from a receiving station in a receivable area or condition. It is an object of the present invention to economically provide a data distribution system in which a receiving station that cannot receive data from a satellite line or has poor reception can reliably obtain desired data.

[0013]

According to the present invention, there is provided a data transmission system utilizing a satellite comprising a data transmitting station, a satellite, and a plurality of receiving stations each comprising an antenna for receiving radio waves from the satellite and a receiving device. In the distribution system, on the ground,
Center station means connected to the data transmitting station for performing backup control of reception of the plurality of receiving stations is provided. The center station means and the plurality of receiving stations are accommodated in a public network and can be connected to each other. When a certain receiving station temporarily receives or fails to receive data via a satellite due to rainfall or the like, the receiving station that cannot receive or wants to receive data is requested from the center station means. Control information for recruiting and selecting a receiving station capable of receiving channel data is distributed via a satellite, and the selected receiving station and the unreceivable or poor reception receiving station are connected using the public line. Accordingly, the present invention provides a data distribution system in which the unreceivable or poor reception receiving station can obtain desired data in real time.

The data distribution systems according to the features of the present invention are listed as follows. According to one aspect of the present invention, there is provided a data distribution system using a satellite including a data transmitting station, a satellite, and a plurality of receiving stations each including an antenna for receiving radio waves from the satellite and a receiving device. A ground station connected to the data transmitting station and performing reception backup control of the plurality of receiving stations is provided on the ground, and the center station and the plurality of receiving stations are accommodated in a public network, and are mutually connected. A wide area data distribution system using a connectable satellite is provided.

According to another feature of the present invention, a data utilizing a satellite comprising a data transmitting station, a satellite, and a plurality of receiving stations each comprising an antenna for receiving radio waves from the satellite and a receiving device. In the distribution system, the data transmitting station has a function of performing backup control of the plurality of receiving stations, and the data transmitting station and the plurality of receiving stations can be housed in a public network and connected to each other. A wide area data distribution system using a satellite is provided.

According to another feature of the present invention, a data utilizing a satellite comprising a data transmitting station, a satellite, and a plurality of receiving stations each comprising an antenna for receiving radio waves from the satellite and a receiving device. In the distribution system, on the ground,
A center station connected to the data transmitting station and performing reception backup control of the plurality of receiving stations is provided, and the center station and the plurality of receiving stations are housed in a public network and can be connected to each other, The distribution station via which the distribution data has been temporarily unreceivable, the reception station requests the center station to perform reception backup control via the public line network,
The center station that has received the request for the reception backup control inquires, via the satellite, a reception station that can perform the reception backup control, and selects one reception station, and the selected reception station is connected via the public network. A wide-area data distribution system using a publicly transmitted satellite is provided to a receiving station that cannot receive received data via the satellite.

According to still another feature of the present invention, a satellite is used which comprises a data transmitting station, a satellite, and a plurality of receiving stations each comprising an antenna for receiving radio waves from the satellite and a receiving device. In the data distribution system, the data transmitting station has a function of performing backup control of the plurality of receiving stations, and the data transmitting station and the plurality of receiving stations are housed in a public network and connected to each other. Enabled, the receiving station that temporarily cannot receive the distribution data via the satellite requests the data transmitting station for reception backup control via the public line network, and issues a request for reception backup control. The received data transmitting station inquires, via the satellite, a receiving backup controllable receiving station, and selects one receiving station.
A wide area data distribution system using a publicly transmitted satellite is provided to a receiving station that cannot receive data via the public network to a receiving station that cannot receive the data via the satellite.

Hereinafter, a data distribution system of the present invention will be described in detail with reference to an embodiment shown in the drawings.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a satellite data distribution system as a background of the present invention will be described.

A satellite data distribution system is a system for distributing data using a satellite from a network between offices of a company to individuals or homes, and a consumer (receiver) transmits information of the received data. , On a receiving terminal such as a personal computer with a built-in digital tuner board.

With this satellite data distribution system, it is possible to provide not only simple data but also electronic media information to consumers from the network between offices of a company to the individual level.

It is expected that the spread of this system will be easy and that a large-scale new market will be created by using a personal computer that has already spread as a data receiving and display terminal. That is, if this system is used at the home or individual level, the spread will accelerate, and the market will further develop based on the spread of personal computers, and has the potential to become a large market.

FIG. 1 shows a system configuration of a satellite data distribution system according to the present invention. This system is roughly divided into three subsystems: a production system 1, a distribution system 2, and a consumption system 3.

The production system 1 is constituted by a production station 4 owned by a content manufacturer or an electronic information maker, and the distribution system 2 is constituted by a transmission station 5 owned by an electronic information distribution and sales company. The data produced by the content maker or the electronic information maker at the production bureau 4 is converted by the electronic information distributor / distributor into electronic information in a format prescribed by the present system, and transmitted from the transmission bureau 5 to the consumer system 3 via the satellite 6. It will be delivered.

Since the consumption system 3 is a feature of the present invention, its configuration will be described in detail with reference to FIGS.

As shown in FIG. 1, the consuming system 3 includes a plurality of receiving stations 31A1 to 31An and 31B1 to 31Bm (m, n
Is a positive integer corresponding to the number of receiving stations. The reason for dividing into A and B will be described later).
1An, 31B1 to 31Bm, and a line 32 between radio waves via a satellite for distribution to all subscribers and a one-to-k
(K = 1, 2,...) And a line 33 which is a public line network capable of communication, and a center 34 connected to the public line.

Receiving stations 31A1-31An, 31B1-3
FIG. 2 shows an example of the receiving station 31Ai as a configuration example of 1Bm. The configuration of FIG. 2 includes all the receiving stations 31A1 to 31An,
31B1 to 31Bm, the antenna 31Ai1 for receiving data by radio waves from the line 32 from the satellite 6 and the digital tuner board 31Ai2 incorporated in the personal computer, which is a receiving device, are basically built in common with the 31B1 to 31Bm. PC 31Ai3.

The personal computer 31Ai3 is a personal computer 31
It is configured around Ai0. PC body 31Ai
To 0, a telephone modem 31Ai4 is connected and connected to the public network line 33. The personal computer 31Ai3 is also provided with a display 31Ai5 and a storage device 31Ai6, which can display, use, and record data.

Using the configuration of FIG. 2, the receiving station 31Ai
Transmits the data received from the satellite line 32 to the public network line 33 of the terrestrial line, thereby transmitting the data to another receiving station, or receiving the data from the other receiving station through the public network line 33. it can. Performed through the public network line 33,
In this embodiment, the communication between the receiving stations is one-to-one, and the other party is specified by a telephone number as in a normal telephone.

As described above, in the consuming system 3 according to the present invention, two lines having different data rates of the satellite line 32 and the terrestrial public line 33 are used for data reception at each receiving station.

Returning to FIG. 1, the satellite line 32 is a line using radio waves from the satellite 6, and transmits the information multiplexed by the transmitting station 5 to a plurality of receiving stations 31A in the consuming system 3 via the satellite 6.
To 31-31An and 31B1-31Bm.

The line 32 from the satellite 6 to the consumer system 3
Is a multiplexed high-speed data line for the purpose of high-speed data batch distribution over a wide area.

That is, many channels are multiplexed and distributed on this line 32, and the receiving stations 31A1 to 31A1
31An and 31B1 to 31Bm each select and contract one or more channels among them. In this case, 1
In general, one receiving station uses a part of the channels, rather than receiving and using all the data multiplexed on the line 32.

More specifically, the data from the satellite 6 is obtained by multiplexing a large number of channels ch1 to chp. p is usually a numerical value on the order of 100 to 1000. Here, a channel is a unit of a set of data distributed simultaneously, such as one program. Which channel each receiving station receives is random, but only one channel can be received at a time.

At each receiving station, the data of the channel specified by the user among the data received via the antenna is recorded and displayed on the personal computer.

[0036] The rate of data acquired by one receiving station is much lower than that being delivered. For example, line 3
Even if 2 is a data rate of 30 Mbps, if the channel used by a certain receiving station is, for example, 64 kbps, the data rate to be obtained is transmitted at a data rate of 64 kbps for this receiving station. It is equivalent to

The satellite line 32 includes an unstable and uncertain element in reception, such as a break due to rainfall.

On the other hand, the line 33 is a public network line, and in this embodiment, a 64 kbps ISND line is used. The feature of this public network line 33 is that the data rate is 64
kbps, which is small for the satellite line 32 and one-to-one communication. For this reason, it is not suitable in terms of cost to distribute the information to a wide area at once, but it is sure in this sense because there is no influence of rainfall or the like.

Hereinafter, the data receiving procedure according to the present invention will be described in detail with reference to the flow chart of FIG.

1. Backup Data Reception Request (Step S310 in FIG. 3) Now, the transmitting station 5 creates transmission data (Step 1),
A number of receiving stations are transmitted to the satellite 6 (step 2), data is distributed (step 3), and the receiving station 31A1 is transmitted.
To 31An and 31B1 to 31Bm, but the receiving stations 31A1 to 31An cannot receive data due to rain (step 3A) (step 4A), and the receiving stations 31B1 to 31Bm receive the data. In a non-existent area (Step 3B) and can be received (Step 4)
B).

Among the receiving stations 31A1 to 31An that cannot receive the data from the satellite line 32, the station that requests the reception of the backup data is the channel number c desired to receive.
h- and the like as request information (step 5A), and the center 34, for example, E
Contact by e-mail or the like (step 7).

The request for receiving the backup data need not be made by all the receiving stations 31A1 to 31An that cannot receive the data, but only by the desired receiving station.

At this time, it is conceivable that communication is concentrated at the center 34, but by increasing the number of receiving lines of the center 34, it is possible to cope with the simultaneous multiple reception. Since this data is very small, at most about several tens of bytes, and one communication time is very short, data from many stations can be received in a short time in a serial manner.

2. Recruitment of backup data supply station (step S320 in FIG. 3) The center 34 obtains the receiving station 31A obtained as described above.
Based on the data request information from 1 to 31An, a table TB1 shown in FIG. 4 is created on a memory not shown in FIG. 1 (8).

As shown in FIG. 4, this table TB1
Is composed of data reception request station information A40 and reception backup station area information B40.

The data reception requesting station information A40 is, as described above, information relating to the station that has requested data backup reception among the stations A that cannot be received via the satellite line 32 due to rainfall or the like. Through the center 34
Is created based on the acquired data. That is, the data reception request station information A40 includes the reception station name 41,
It comprises a receiving station ID 42, a receiving station telephone number 43, and a backup reception request channel number 44.

On the other hand, reception backup station area information B40
Is information that specifies the area of a station that performs backup reception with respect to the receiving station A in the data receiving requesting station information A40 for each receiving station A. Specifically, for example, the area code—the local station number It is composed of a combination.

Returning to FIG. 3, the center 34 transmits the data in the table TB1 of FIG. 4 to the transmitting station 5 using the public network line 33 (step 10) (step 9).
(Step 11).

The transmitting station 5 transmits the received data of the table TB1 to the satellite 6 using one channel of the satellite line 32 or as ancillary data of a certain channel of the satellite line 32 (step 12). Receiving station 31A
It distributes to 31-31An and 31B1-31Bm (step 13B).

The data corresponding to the table TB1 in FIG. 4 can be obtained only by the receiving stations 31B1 to 31Bm that can receive data from the satellite line 32 at that time (14B), and the receiving stations 31A1 to 31An located in the area where it is raining can be obtained. Cannot be received (14A). The table TB1 has a data amount of less than 1 MB (megabyte), and the time and cost are small even if the public network line 33 is used.

The data in the table TB1 received by the receiving stations 31B1 to 31Bm is determined by each receiving station as to whether backup data can be supplied by the own station or not. If backup data can be supplied, the data can be supplied. The response is transmitted to the center 34 via the public network line 33 (16) (15B). That is, the receiving stations 31B1 to 31Bm that have received the data of the table TB1 transmit the channel number ch− that can be received by the own station and can supply the data through the public network line 33 in accordance with the reception content of each receiving station.
The center 34 is notified by e-mail or the like. This step (15B) does not need to be performed by all the receiving stations 31B1 to 31Bm, and only the desired receiving station may be performed.

In the above description, the “channel number ch- to which data can be supplied” is the number of a channel which is scheduled to be received and can transmit data of the channel using the public network line 33 at the same time as receiving.

The center 34 receives the channel number information from the receiving stations 31B1 to 31Bm (step 1).
7).

Here, the area designation code B41 of the data supply station in FIG. 4 will be described. Due to the wide area of the satellite-based data distribution system, the area where the rainfall becomes unreceivable due to rainfall or the like is smaller than the entire receiving station. In other words, the number m of the receiving stations 31B1 to 31Bm in the non-rain area where satellite line data can be received is much larger than the number n of the receiving stations 31A1 to 31An that are poorly received or cannot be received in the rain area.

Since the data from the receiving stations 31B1-31Bm is very small, about several tens of bytes, the center 34
Communication time is very short, but still the receiving station 31A
Compared to the case where communication is received for 1-31An,
When receiving data with a limited number of lines at the center 34, much more time is required. It is not economical to further increase the number of lines in the center in order to reduce this time.

Therefore, in the present invention, by limiting the area of the receiving stations 31B1 to 31Bn to be communicated,
Communication is concentrated at the center 34 and the reception is prevented from being saturated at the center 34. Hereinafter, an example of this area limitation method will be described.

In the example shown in FIG. 4, the target receiving stations 31B1 to 31Bm are limited in area under the following conditions (1) to (3).

(1) Based on weather information, an area is set where reception is possible for a required time.

(2) In an area relatively close to the receiving stations 31A1 to 31An, consideration is given so that the line charge of the public line network does not increase.

(3) Target receiving stations 31B1 to 31B
The number m of m is limited to be about several times (for example, twice) the number n of the receiving stations 31A1 to 31An.

If the receiving stations 31A1 to 31An are dispersed in some areas, the receiving stations 31B1 to 31Bm must also be dispersed and designated.

In the embodiment, the designation of the area limitation based on the above conditions is performed by the local area code and the area code of the telephone number. FIG.
Such area limitation information is added to the reception data requesting station information.

3. Determination of Backup Data Supply Station (Step S330 in FIG. 3) The center station 6 uses this information to receive the stations 31A1 to 31A.
n, a table TB2 shown in FIG. 5 is created in which the desired channel numbers, such as the addresses and telephone numbers of the receiving stations 31B1-31Bm, and the currently received channel numbers are associated (step 18).

A method for creating the table TB2 will be described below. This table TB2 contains, as reception station information A50 that cannot be received and has a request to receive backup data,
Receiving station name A51, receiving station ID A52 and telephone number A
53, Reception station information B50 capable of supplying backup data
The association of the receiving station name B51, the receiving station ID B52, the telephone number B53, and the channel number C51 as the common information C50 is recorded.

For example, the receiving station 31Ai and the receiving station 31A
A data transmission instruction is written in association with a receiving station 31Bj capable of receiving and supplying data by receiving the same channel as i has received. At this time, even for the same channel, a plurality of receiving stations 31Ai desire and a plurality of receiving stations 31B
j can supply data, but it is desirable to instruct the receiving stations 31Ai and 31Bj to perform one-to-one communication as much as possible. For this purpose, the range of area designation of the receiving stations 31B1 to 31Bm is determined to be wider so that the number of the receiving stations 31B- is sufficiently larger than the number of the receiving stations 31A-. Even if the receiving station 31Bj that cannot supply data is determined in this way, there is no problem in the present system.

However, since the area designation is based on the prediction to the last, the opposite situation occurs and the receiving station 3 to which no data is supplied is provided.
1Ai may occur. In this case, one to two
The number of stations performing (communication on the transmission side 1 and the reception side 2) is sequentially increased. If there is still a shortage, the operations are sequentially performed in the order of 1: 3, 1: 4.

Returning to FIG. 3, the center 34 transmits the data in the table TB2 of FIG. 5 to the transmitting station 5 to the transmitting station 5 using the public network line 33 (step 20) (step 19). ). This table TB2 also has a data amount of less than 1 MB, and the time and cost are small even if the line 33 is used.

The transmitting station 5 converts the data in the table TB2 into
It is distributed using one channel of the satellite line 32 or as ancillary data of a certain channel. This table TB2 distributed using the satellite line 32 is distributed to all the receiving stations 31A1 to 31An and 31B1 to 31Bm (step 23A) (step 23B), but only the receivable receiving stations 31B1 to 31Bm can be obtained. (Step 2
4B).

3. Supply of Backup Data (Step S340 in FIG. 3) Receiving stations 31B1 to 31Bm look at this table TB2 and receive an instruction to transmit data via the public network line 33. Then, the backup data is transmitted to (-) (step 24B). This is a one-to-one communication between the receiving station 31Bj and the receiving station 31Ai via the public network line 33, and does not involve the center 34.

The backup data is transmitted, for example, at a data rate of 64 kbps from the receiving station 31Bj to the receiving station 31Ai.

In the first embodiment shown in FIG.
Although the case where the center 34 is provided separately from the transmitting station 5 is shown,
As shown in the second embodiment in FIG.
A configuration in which the transmission station 5 is integrated into the transmission station 5 is also possible.

[0072]

As described above, according to the present invention, data received from a receiving station in a receivable area and conditions is transmitted to a receiving station temporarily unreceivable due to rainfall or the like. By doing so, it becomes possible for receiving stations that cannot receive each other to acquire data.

[Brief description of the drawings]

FIG. 1 is a block configuration diagram of a satellite data distribution system according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a receiving station in FIG. 1;

FIG. 3 is a diagram showing a procedure flow according to the present invention.

FIG. 4 is a diagram showing a table 1 distributed from a center according to the present invention.

FIG. 5 is a diagram showing a table 2 distributed from the center according to the present invention.

FIG. 6 is a block diagram of a satellite data distribution system according to a second embodiment of the present invention.

[Explanation of symbols]

1: Production system, 2: Distribution system, 3: Consumption system, 4: Production system, 5
... Sending station, 6 ... Satellite, 31A ... Receiving station, 31B ... Receiving station, 32 ... Satellite line, 33 ... Public communication network, 34 ... Center, TB1 ... Table 1, TB2 ... Table 2

Claims (4)

[Claims] 1. A data distribution system using a satellite comprising a data transmitting station, a satellite, and a plurality of receiving stations each including an antenna for receiving radio waves from the satellite and a receiving device, wherein: A center station connected to a data transmitting station and performing backup control of reception of the plurality of receiving stations is provided, and the center station and the plurality of receiving stations are accommodated in a public network and can be connected to each other. Wide area data distribution system using satellites. 2. A data distribution system using a satellite comprising a data transmitting station, a satellite, and a plurality of receiving stations each including an antenna for receiving radio waves from the satellite and a receiving device. Has a function of performing backup control of reception of the plurality of receiving stations, and accommodates the data transmitting station and the plurality of receiving stations in a public line network so that they can be connected to each other. Wide-area data distribution system using 3. A data distribution system using a satellite comprising a data transmitting station, a satellite, and a plurality of receiving stations each comprising an antenna for receiving radio waves from the satellite and a receiving device, wherein: A center station connected to a data transmitting station and performing backup control of reception of the plurality of receiving stations is provided. The receiving station, which has become unable to receive distribution data via the satellite temporarily, requests the center station to perform reception backup control via the public line network. Inquiring a receiving station capable of receiving backup control via the satellite, selecting one receiving station, and selecting the receiving station via the public switched telephone network. , The non-reception station received via the satellite, a wide area data distribution system using satellites, characterized by public transmission. 4. A data distribution system using a satellite comprising a data transmitting station, a satellite, and a plurality of receiving stations each including an antenna for receiving radio waves from the satellite and a receiving device. Has a function of performing backup control of reception of the plurality of receiving stations, and accommodates the data transmitting station and the plurality of receiving stations in a public line network so that they can be connected to each other and distributes the data via the satellite. The receiving station in which data is temporarily unreceivable requests the data transmitting station to perform reception backup control via the public line network. A controllable receiving station is inquired via the satellite to select one receiving station, and the selected receiving station transmits the data that can be received via the public network to the To unreceivable receiving station via star, wide area data distribution system using satellites, characterized by public transmission.