JP3561910B2

JP3561910B2 - Satellite data distribution system

Info

Publication number: JP3561910B2
Application number: JP2000153879A
Authority: JP
Inventors: 昭宏内田
Original assignee: NEC Corp
Current assignee: NEC Corp
Priority date: 2000-05-24
Filing date: 2000-05-24
Publication date: 2004-09-08
Anticipated expiration: 2020-05-24
Also published as: JP2001339332A

Description

【０００１】
【発明の属する技術分野】
本発明は衛星データ配信システムに関する。
【０００２】
【従来の技術】
衛星通信は、地球を回る軌道上に打ち上げた人工衛星を中継して行なう無線通信であり、センタ局（送信局）から多数の受信端末に対して片方向のデータ配信を行う衛星データ配信システムも、このような衛星通信の内の一つである。衛星通信は、通信可能区域が広く、高速の伝送が可能である上、地理的障害の克服，通信品質の均一性，耐災害性などの利点を有する。その反面、降雨や降雪などの気象状況の影響を受け易く、伝送遅延時間が大きいという欠点がある。
【０００３】
従来からも、衛星通信の欠点を補うための多くの改善技術が提案されている。特開平９−３６７９０号公報に記載の「衛星通信回線バックアップ方法」は、子局と通信衛星間に障害が発生した場合には、障害が発生した子局が良好な他の子局を介して衛星通信が行なえるようにしている。地上回線で迂回するのである。また、特開平１−２９３０２０号公報に記載の「衛星通信システムの回線切替制御装置」は、地上局の衛星アクセス装置を介して衛星回線に接続された相互間でデータ通信を行うホスト計算機および端末を、衛星回線の異常時に地上迂回回線に切替える。更に、特開平３−５８６３２号公報に記載の「衛星通信ネットワークの回線障害救済方式」は、衛星リンク障害を衛星通信用超小型地上局障害として認知し、地上公衆回線網に衛星通信形態を代替する。更に、特開平１１−２９８４７４号公報に記載の「衛星を利用した広域データ配信システム」は、降雨等により受信電波が低下し、衛星からデータを一時的に受信できなくなった受信局と、受信可能な受信局とを対応させる情報を衛星を介して配信することにより、受信可能局が受信できたデータを公衆回線網を用いて受信不可能局に送信するものである。
【０００４】
このように、従来の衛星通信システムは、衛星データ送信を行う直前、あるいはデータ受信失敗を確認した後に、衛星信号レベルの低下やデータ未到達を検知して、地上系への迂回を試みるものである。
【０００５】
【発明が解決しようとする課題】
しかし、上述した従来技術の第１の問題点は、通信失敗の要因を気象状況に限定しているということである。受信端末は衛星受信だけを行う専用装置である場合もあるが、衛星受信以外に受信したデータの配布や後処理機能を兼ねる場合もある。ユーザ向けのサービスを行う端末機能と衛星受信機能が同一装置に実装される場合には、通信失敗の要因にこれらの機能をも加えることが必要である。すなわち、衛星受信以外の処理を行なう場合には、衛星受信以外の処理負荷の影響で、受信端末の処理能力が一時的に低下し、受信端末において衛星データ受信に失敗したり、受信端末にデータが到達する時間が長くなる場合があるからである。
【０００６】
第２の問題点は、衛星データ通信失敗の検知が事後にしか行えないということである。データ配信が失敗したことを確認してから衛星送信の地上系への迂回を事後に行うのでは、所期の時間内に全端末へのデータ到達を保証することができず、端末にデータが届く時刻が大きく遅れることになる。
【０００７】
本発明は、このような問題に鑑みなされたものであって、その第１の目的は、衛星データ配信の受信失敗確率を低減し、衛星回線の利用効率を高めた衛星データ配信システムを提供することにある。
【０００８】
また、本発明の第２の目的はデータ到達の時間を短縮できる衛星データ配信システムを提供することにある。
【００１０】
【課題を解決するための手段】
第１の本発明の衛星データ配信システムは、センタ局(2)から通信衛星(1)を介して少なくとも一つの受信端末(10,20)にデータを配信する衛星データ配信システムにおいて、受信端末(10,20)は、センタ局(2)から配信されデータを受信する衛星受信手段(11,21)と、受信したデータが受信確認用のデータであれば、その受信成否を格納する受信履歴情報管理手段(12,22)と、受信履歴情報管理手段(12,22)に格納された受信履歴情報を即時に、あるいは一定時間間隔で地上回線によってセンタ局(2)に送信する地上回線送信手段(13,23)とを備え、センタ局(2)は、通信衛星(1)を介して受信端末(10,20)に向け、一定時間間隔で受信確認用のデータ、または本来の配信目的のデータを送信する衛星送信手段（3）と、受信確認用のデータに対して収集された受信履歴情報を受信端末(10,20)から受信する地上回線受信手段(6)と、受信した受信履歴情報に基づいて時間帯ごとの受信成功率を集計する時間帯別受信成功率集計手段(5)と、時間帯別受信成功率集計手段(5)が集計した時間帯別受信成功率に基づいて最も受信成功率の高い時間帯に集中した配信スケジュールを受信端末(10,20)ごとに作成する配信スケジュール作成手段(4)とを備え、衛星送信手段(3)はこのスケジュールに従って本来の配信目的のデータを送信することを特徴とする。
【００１１】
第２の本発明の衛星データ配信システムは、センタ局(2)から通信衛星(1)を介して少なくとも一つの受信端末(10,20)にデータを配信する衛星データ配信システムにおいて、受信端末(10,20)は、センタ局(2)から配信されデータを受信する衛星受信手段(11,21)と、受信したデータが受信確認用のデータであれば、その受信成否を格納する受信履歴情報管理手段(12,22)と、受信履歴情報管理手段(12,22)に格納された受信履歴情報を即時に、あるいは一定時間間隔で地上回線によってセンタ局(2)に送信する地上回線送信手段(13,23)とを備え、センタ局(2)は、通信衛星(1)を介して受信端末(10,20)に向け、一定時間間隔で受信確認用のデータ、または本来の配信目的のデータを送信する衛星送信手段（3）と、受信確認用のデータに対して収集された受信履歴情報を受信端末(10,20)から受信する地上回線受信手段(6)と、受信した受信履歴情報に基づいて時間帯ごとの受信成功率を集計する時間帯別受信成功率集計手段(5)と、気象予報情報を管理する気象予報情報管理手段(7)と、時間帯別受信成功率集計手段(5)が集計した時間帯別受信成功率および気象予報情報管理手段(7)が管理する気象予報情報に基づいて最も受信成功率の高い時間帯に集中した配信スケジュールを受信端末(10,20)ごとに作成する配信スケジュール作成手段(4)とを備え、衛星送信手段(3)はこのスケジュールに従って本来の配信目的のデータを送信することを特徴とする。
【００１３】
本発明では、センタ局から通信衛星を介して少なくとも一つの受信端末にデータを配信する衛星データ配信方法において、先ず、センタ局から通信衛星を介して受信端末に向け、一定時間間隔で前記受信確認用のデータを送信する。センタ局から配信され受信確認用のデータを受信端末が受信し、受信した受信確認用のデータについてその受信成否を格納する。格納された受信成否の受信暦歴情報は即時に、あるいは一定時間間隔で地上回線によってセンタ局に送信される。センタ局はこれを受信し、受信した受信暦歴情報に基づいて受信成功率を時間帯ごとに集計する。そして、集計した時間帯別受信成功率に基づいて最も受信成功率の高い時間帯に集中した配信スケジュールを受信端末ごとに作成し、この配信スケジュールに従って本来の配信目的のデータを送信する。なお、配信スケジュールを作成するときに、気象状況を加味してもよい。
【００１４】
本発明は、このように、予測受信成功率に基づいて、受信端末でのデータ受信成功率が最も高くなる時間帯にデータ配信時刻をスケジュールする構成としたため、短時間での確実な配信，適正な回線使用時間での送信の実現を可能にする。また、衛星データ配信では、同一のデータを複数回送信することにより全体として受信成功率を高める方法が知られている。このような場合、本発明の予想受信成功率に基づいた配信スケジュール方法によれば、同一のファイルが受信成功率の低い時間帯に繰り返し送信されることが無いように配信時間を分散させることにより、受信成功率が同一の環境であっても全体としての受信成功率を高めることが可能になる。
【００１５】
【発明の実施の形態】
次に、本発明の実施の形態について図面を参照して説明する。
【００１６】
図１を参照すると、本発明の衛星データ配信システムの一実施例は、通信衛星１と、衛星データを配信する送信局としてのセンタ局２と、２つの受信端末１０，２０とからなる。通信衛星１は、赤道上空の軌道上に打ち上げられた静止衛星である。センタ局２は、受信端末１０，２０に対して通信衛星１を経由してデータを配信する。受信端末１０，２０は、例えば、事務所のように数箇所程度に設置される場合から、全国展開のコンビニエンスストアやガソリンスタンドのように一万箇所以上に設置される場合までがある。受信端末１０，２０は、通信衛星１からデータを受信する処理以外に、受信したデータの配布や後処理をも行なう。
【００１７】
図１では２つの受信端末１０，２０を示しているが、これらは同構成であるので、以降、受信端末１０について説明する。受信端末１０は、通信衛星１からデータを受信する衛星受信手段１１の他に、受信履歴情報を管理する受信履歴情報管理手段１２と、受信履歴情報を地上回線経由でセンタ局２に送信する地上回線送信手段１３から構成されている。
【００１８】
センタ局２は、通信衛星１へデータを送信する衛星送信手段３の他に、気象予報情報を管理する気象予報情報管理手段７，受信端末１０，２０からの受信履歴情報を受信する地上回線受信手段６，受信した受信履歴情報を集計する時間別受信成功率集計手段５、および気象予報情報管理手段７が管理する気象予報情報と時間別受信成功率集計手段５が集計した時間別受信成功率とから配信データのスケジュールを作成する配信スケジュール作成手段４とを含む。
【００１９】
これらの手段はそれぞれ概略次ぎのように動作する。まず、センタ局２の衛星送信手段３は、通信衛星１を介して受信端末１０，２０に向け、一定時間間隔で受信確認用のデータ、または本来の配信目的のデータを送信する。受信端末１０の衛星受信手段１１は、配信されデータを受信し、それが受信確認用のデータであれば、その受信成否を受信履歴情報管理手段１２に格納する。地上回線送信手段１３は、受信履歴情報手段１２に格納された受信履歴情報を受信後即時に、あるいは一定時間間隔で地上回線によってセンタ局２に送信する。また、受信したデータが本来目的のものであれば、受信端末１０では、このデータの配布や後処理を行なう。地上回線送信手段１３は、また地上回線を使用してのセンタ局２との一般的な通信手段ともなる。図１には、この点に関して、受信端末１０からセンタ局２方向の経路しか示されていないが、実際には逆方向の経路も設けられている。
【００２０】
センタ局２の地上回線受信手段６は、受信端末１０，２０から、受信確認用のデータに対して収集された受信履歴情報を受信する。時間帯別受信成功率集計手段５は受信履歴情報に基づいて時間帯ごとの受信成功率を集計する。図２は、受信端末１０，２０から送られてきた受信履歴情報により、時間帯別受信成功率集計手段５が集計した時間帯別受信成功率の例を表示したものである。この例では、受信端末１０は、深夜から未明にかけてバッチ処理を実行しているので０時−６時の時間帯の受信確率が特に低く、午後から夜間は受信確率が高いとされている。
【００２１】
配信スケジュール作成手段４は、このような時間帯別受信成功率に基づいて、最も受信成功率の高い時間帯に集中した配信スケジュールを受信端末１０，２０ごとに作成する。衛星送信手段３はそのスケジュールに従ってデータを送信する。
【００２２】
次に、時間帯ごとの受信成功率だけでなく、気象予報情報管理手段７が管理する地域・時間帯別気象予報情報を加味した配信スケジュールを作成することで、さらに効率的な配信スケジュールの作成を可能とする。衛星通信の宿命ともいうべき気象条件に配慮するのである。晴天の場合は受信への影響はないが、降雨時には受信確率が低下し、特に、雷雨時など強い雨が降っている場合には受信への影響が大きい。図３は、気象予報情報管理手段７が管理する地域・時間帯別気象予報情報の一例を表示するものである。
【００２３】
センタ局２は当然、受信端末１０，２０が設置されている地域の情報を保持している。図４は、このような情報の一例を端末設置場所一覧として表示する。図１では２つの受信端末１０，２０を示したが、事例を多くするために、ここでは３つの受信端末Ａ，Ｂ，Ｃとしている。配信スケジュール作成手段４は、図３の地域・時間帯別気象予報情報と図４の端末設置場所一覧とを合体させて、図５に示すような受信端末気象情報を作成する。
【００２４】
いま、センタ局２は、受信端末Ａに配信データ１、受信端末Ｂに配信データ２、受信端末Ｃに配信データ３を送信するものとし、かつ受信確率を高めるために同一の配信データを２回つづ繰り返して送信するものとする。配信スケジュール作成手段４は、このような配信計画の下、図２の時間帯別受信成功率および図５の受信端末気象情報を参照しながら、受信端末Ａ，Ｂ，Ｃごとの配信スケジュールを作成する。先ず、雨の時間帯を避け、晴れの時間帯の中では受信確率の高い方を選択する。例えば、受信端末Ａの地域は、図５から明らかなように、晴れの時間帯が３つあるが、時間帯別受信確率の低い０時−６時は避け、６時−１２時に第１回の配信データ＃１を送信し、次いで１２時−１８時に第２回の配信データ＃２を送信する。
【００２５】
図７は、以上に説明した受信成功率に地域・時間帯別気象予報情報を加味して配信スケジュールを作成する場合の概略フローを示す。更に、図８のフローチャートを参照して、本実施例において配信スケジュールを作成する場合の動作について詳細に説明する。
【００２６】
先ず、センタ局２から一定時間間隔で受信確認用データを全受信端末１０，２０に向けて衛星配信を行う（図２のステップ１０１）。次に、受信端末１０，２０での受信成否情報を収集し（図２のステップ１０２）、この情報から時間帯別の受信成功率を計算する（図２のステップ１０３）。更に、気象予報機関より配信スケジュールを組む時間帯ごとの気象予報情報を入手し（図２のステップ１０４）、この情報を加味して配信スケジュール対象時間帯での予想受信成功確率を計算して求める（図２のステップ１０５）。
【００２７】
衛星データ配信では、データの受信成功率を高めるために、同一のデータを繰り返し送信する手法が採用される場合が多い。繰り返し送信がない場合は、受信成功率の高い時間帯から順次配信データをスケジュールしてゆく（ステップ１０７）。繰り返し送信を行う場合も同様であるが、受信成功率の低い時間帯の中で同一のデータを繰り返し配信しないようにスケジュールを作成する（ステップ１０８）。これによって、受信成功率の低い時間帯に同じファイルの繰り返し送信を行う無駄を排除する。
【００２８】
なお、以上に説明した衛星データ配信方法をコンピュータに実行させるためのプログラムを半導体メモリ，フロッピーディスク，ＣＤ−ＲＯＭ等の記録媒体に記録してコンピュータに読み込ませ実行するようにしてもよい。それらのプログラムの内のセンタ局２にロードされるプログラムは、センタ局２を構成するコンピュータを制御し、そのコンピュータを衛星送信手段３，配信スケジュール作成手段４，時間帯別受信成功率集計手段５，地上回線受信手段６および気象予報情報管理手段７として機能させる。また、プログラムの内の受信端末１０にロードされるプログラムは、受信端末１０を衛星受信手段１０，受信履歴情報管理手段１２および地上回線送信手段１３として機能させる。
【００２９】
【発明の効果】
本発明の第１の効果は、衛星データ配信の受信失敗確率を低減し，衛星回線の利用効率を高められるということである。その理由は、受信端末から収集した時間帯別の受信成功率情報を使用して、または気象予報情報を加味して配信スケジュールを作成することとしたので、受信端末の負荷状況や気象状況によって受信失敗確率が高い時間帯を避けることが可能なためである。同一のデータを繰り返し配信する方式を採用している場合には、受信成功率の低い時間帯に同一のデータが繰り返し配信されないように配信スケジュールを分散化させることにより、受信成功率が同じ環境であっても，全体の受信成功率を高めることが可能になる。
【００３０】
また、本発明の第２の効果は、データ到達の時間を短縮できるということである。衛星を使ったデータ配信が失敗した場合、衛星を使った再送、あるいは地上回線に切り替えて別ルートでの再送を行うことによりデータ到達を保証する方法が知られている。しかし、再送が完了するまでには余分な時間が必要である。本発明によれば、あらかじめ受信成功確率の高い時間帯に集中して配信する、あるいは信成功率が低い時間帯に送信する必要がある場合には、早い段階で別の送信手段に切り替えることによりデータ到達時間を早めることが可能なためである。
【図面の簡単な説明】
【図１】本発明の一実施の形態を示す構成図
【図２】本発明において使用される時間帯別受信成功率の例を表示する図
【図３】本発明において使用される地域・時間帯別気象予報情報の例を表示する図
【図４】本発明において使用される端末設置場所一覧の例を表示する図
【図５】本発明において作成される受信端末気象情報の例を表示する図
【図６】本発明において作成されるデータ配信スケジュールの例を表示する図
【図７】本発明における配信スケジュールを作成する場合の概略フローチャート
【図８】本発明における配信スケジュールを作成する場合の詳細フローチャート
【符号の説明】
１通信衛星
２センタ局
３衛星送信手段
４配信スケジュール作成手段
５時間帯別受信成功率集計手段
６地上回線受信手段
７気象予報情報管理手段
２０受信端末
２１衛星受信手段
２２受信履歴情報管理手段
２３地上回線送信手段
３０受信端末
３１衛星受信手段
３２受信履歴情報管理手段
３３地上回線送信手段[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a satellite data distribution system.
[0002]
[Prior art]
Satellite communication is wireless communication performed by relaying an artificial satellite launched in orbit around the earth. There is also a satellite data distribution system that distributes data in one direction from a center station (transmitting station) to a large number of receiving terminals. Is one such satellite communication. 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]
Conventionally, many improved techniques for compensating for the shortcomings of satellite communication have been proposed. The "satellite communication line backup method" described in Japanese Patent Application Laid-Open No. 9-36790 discloses a method in which, when a fault occurs between a slave station and a communication satellite, the faulty slave station communicates with another good slave station. Satellite communication is available. They make a detour on the ground line. Further, a "line switching control device for a satellite communication system" described in Japanese Patent Application Laid-Open No. 1-293020 discloses 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. Further, the "line failure remedy method for satellite communication network" described in Japanese Patent Application Laid-Open No. 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. Furthermore, the "wide-area data distribution system using satellites" described in Japanese Patent Application Laid-Open No. H11-298474 is capable of receiving data from a receiving station whose reception radio wave is temporarily reduced due to rainfall or the like, and data cannot be received from the satellite temporarily. By distributing information corresponding to various receiving stations via a satellite, data received by the receivable station is transmitted to the unreceivable station using a public network.
[0004]
As described above, the conventional satellite communication system attempts to make a detour to the terrestrial system immediately before performing satellite data transmission or after confirming that data reception has failed, by detecting a decrease in satellite signal level or data non-arrival. is there.
[0005]
[Problems to be solved by the invention]
However, the first problem of the above-described 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 processing other than satellite reception is performed, the processing capacity of the reception terminal temporarily decreases due to the processing load other than satellite reception, and satellite data reception fails at the reception terminal or data is not transmitted to the reception terminal. This is because the time to reach may be long.
[0006]
The second problem is that a satellite data communication failure can be detected only after the fact. If after confirming that data distribution has failed, the satellite transmission to the terrestrial system is performed afterwards, it is not possible to guarantee that data will reach all terminals within the expected time. The arrival time will be greatly delayed.
[0007]
The present invention has been made in view of such a problem, and a first object of the present invention is to provide a satellite data distribution system in which the reception failure probability of satellite data distribution is reduced and the utilization efficiency of satellite links is increased. It is in.
[0008]
A second object of the present invention is to provide a satellite data distribution system capable of shortening the data arrival time.
[0010]
[Means for Solving the Problems]
A satellite data distribution system according to a first 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). (10, 20) are satellite receiving means (11, 21) for receiving data distributed from the center station (2), and reception history information for storing the success or failure of received data if the received data is data for confirmation of reception. Management means (12, 22) and terrestrial line transmitting means for transmitting the reception history information stored in the reception history information management means (12, 22) to the center station (2) via the terrestrial line immediately or at regular time intervals. (13, 23), and the center station (2) transmits the data for reception confirmation at regular time intervals to the receiving terminal (10, 20) via the communication satellite (1), or the data for the original distribution purpose. Satellite transmission means (3) for transmitting data and reception history information collected for data for confirmation of reception are received. Ground line receiving means (6) for receiving from the terminals (10, 20), time-based reception success rate totalization means (5) for totalizing reception success rates for each time zone based on received reception history information, and time Creation of a distribution schedule for each receiving terminal (10, 20), based on the reception success rate for each time period, which is compiled by the reception success rate totaling means for each band (5), based on the reception success rate for each time period. Means (4), wherein the satellite transmitting means (3) transmits the original data for distribution in accordance with the schedule.
[0011]
A satellite data distribution system according to a second 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). (10, 20) are satellite receiving means (11, 21) for receiving data distributed from the center station (2), and reception history information for storing the success or failure of received data if the received data is data for confirmation of reception. Management means (12, 22) and terrestrial line transmitting means for transmitting the reception history information stored in the reception history information management means (12, 22) to the center station (2) via the terrestrial line immediately or at regular time intervals. (13, 23), and the center station (2) transmits the data for reception confirmation at regular time intervals to the receiving terminal (10, 20) via the communication satellite (1), or the data for the original distribution purpose. Satellite transmission means (3) for transmitting data and reception history information collected for data for confirmation of reception are received. Terrestrial line receiving means (6) for receiving from the terminals (10, 20), reception success rate totaling means for each time zone for totalizing the reception success rate for each time zone based on the received reception history information (5), Meteorological forecast information management means (7) that manages forecast information, and time-of-day reception success rate that is summed up by the time-of-day reception success rate totaling means (5) and weather forecast information managed by the weather forecast information management means (7) Distribution schedule creating means (4) for creating, for each receiving terminal (10, 20), a distribution schedule concentrated in the time zone with the highest reception success rate based on the satellite transmission means (3). Is transmitted.
[0013]
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, the center station is directed to the receiving terminal via the communication satellite, and the reception confirmation is performed at regular time intervals. Send data for 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 on the success or failure of the reception is transmitted to the center station immediately or at fixed time intervals via a ground line. The center station receives this, and tabulates 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 totaled time-successful reception success rates, and data intended for original distribution is transmitted according to the distribution schedule. When creating a distribution schedule, weather conditions may be taken into account.
[0014]
As described above, according to the present invention, the data distribution 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. It is possible to realize transmission in a short line use time. In satellite data distribution, a method is known in which the same data is transmitted a plurality of times to increase the overall reception success rate. In such a case, according to the distribution scheduling method based on the expected reception success rate of the present invention, the distribution time is dispersed 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 rate is the same, the overall reception success rate can be increased.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
[0016]
Referring to FIG. 1, one embodiment of the satellite data distribution system of the present invention includes a communication satellite 1, a center station 2 as a transmitting station for distributing satellite data, and two receiving terminals 10 and 20. The communication satellite 1 is a geostationary satellite launched into an orbit above the equator. The center station 2 distributes data to the receiving terminals 10 and 20 via the communication satellite 1. For example, the receiving terminals 10 and 20 may be installed at several places like an office, or may be installed at more than 10,000 places like a convenience store or a gas station nationwide. The receiving terminals 10 and 20 perform not only the process of receiving data from the communication satellite 1 but also the distribution and post-processing of the received data.
[0017]
Although FIG. 1 shows two receiving terminals 10 and 20, they have the same configuration, and therefore, 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.
[0018]
The center station 2 includes, in addition to the satellite transmission means 3 for transmitting data to the communication satellite 1, a weather forecast information management means 7 for managing weather forecast information, and a terrestrial line reception for receiving reception history information from the receiving terminals 10 and 20. Means 6, hourly reception success rate totalizing means 5 for totalizing received reception history information, and hourly reception success rate totaled by weather forecast information and hourly reception success rate totaling means 5 managed by weather forecast information management means 7 And distribution schedule creating means 4 for creating a schedule of distribution data from the above.
[0019]
Each of these means operates roughly 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 terrestrial line transmitting means 13 also serves as general communication means with the center station 2 using the terrestrial line. Although FIG. 1 shows only a route from the receiving terminal 10 to the center station 2 in this regard, a route in the opposite direction is actually provided.
[0020]
The terrestrial line receiving means 6 of the center station 2 receives, from the receiving terminals 10 and 20, reception history information collected for data for reception confirmation. The time zone-based reception success rate totaling means 5 totalizes the reception success rates 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 process from midnight to early morning, the reception probability in the time zone from 0:00 to 6:00 is particularly low, and the reception probability is high from the afternoon to night.
[0021]
The distribution schedule creating means 4 creates a distribution schedule concentrated on the time zone having the highest reception success rate for each of the receiving terminals 10 and 20 based on the reception success rate for each time zone. The satellite transmitting means 3 transmits data according to the schedule.
[0022]
Next, a more efficient distribution schedule is created by creating a distribution schedule that takes into account not only the reception success rate for each time zone but also weather forecast information for each area and time zone managed by the weather forecast information management means 7. Is possible. 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 the reception, but the reception probability decreases in the case of rainfall, and the influence on the reception is large particularly in the case of heavy rain such as 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.
[0023]
The center station 2 naturally 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. Although two receiving terminals 10 and 20 are shown in FIG. 1, three receiving terminals A, B, and C are used here to increase the number of cases. The distribution schedule creating 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 receiving terminal weather information as shown in FIG.
[0024]
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 transmits the same distribution data twice to increase the receiving probability. It shall be repeatedly transmitted. Under such a distribution plan, the distribution schedule creating means 4 creates a distribution schedule for each of the receiving terminals A, B, and C while referring to the reception success rate by time zone in FIG. 2 and the weather information of the receiving terminal in FIG. I do. First, avoid the rainy time zone and select the one with the higher reception probability in 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.
[0025]
FIG. 7 shows a schematic flow in the case where a distribution schedule is created by taking into account the weather forecast information for each region and time zone in addition to the reception success rate described above. Further, with reference to the flowchart of FIG. 8, the operation when creating a distribution schedule in the present embodiment will be described in detail.
[0026]
First, satellite data is distributed from the center station 2 to all the receiving terminals 10 and 20 at regular intervals (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 this information (step 103 in FIG. 2). Furthermore, weather forecast information for each time zone for which a distribution schedule is to be obtained from the weather forecasting organization (step 104 in FIG. 2), and taking this information into account, the expected reception success probability in the time zone targeted for the distribution schedule is calculated and obtained. (Step 105 in FIG. 2).
[0027]
In satellite data distribution, a technique of repeatedly transmitting the same data is often adopted in order to increase the data reception success rate. If there is no repetitive transmission, the distribution data is scheduled sequentially from a time zone with 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 during 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.
[0028]
A program for causing a computer to execute the satellite data distribution method described above may be recorded on a recording medium such as a semiconductor memory, a floppy disk, or a CD-ROM, and read and executed by the computer. Among these programs, the program loaded into the center station 2 controls a computer constituting the center station 2 and divides the computer into satellite transmission means 3, distribution schedule creation means 4, reception success rate totaling means by time zone 5, , Functions as a ground 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 unit 10, the reception history information managing unit 12, and the terrestrial line transmitting unit 13.
[0029]
【The invention's effect】
A first effect of the present invention is that the reception failure probability of satellite data distribution 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 probability of failure 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 in the time zone where the reception success rate is low, the environment can be used in the environment where the reception success rate is the same. Even if there is, it is possible to increase the overall reception success rate.
[0030]
A second effect of the present invention is that the time for data arrival can be reduced. When data distribution using a satellite fails, there is known a method of guaranteeing data arrival by performing retransmission using a satellite or retransmission by switching to a terrestrial line and using another route. However, extra time is required until retransmission is completed. According to the present invention, distribution is concentrated in advance in a time zone with a high reception success probability, or when transmission is required in a time zone with a low success rate, by switching 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 by time zone used in the present invention; FIG. 3 is a region / time used in the present invention; FIG. 4 is a diagram showing an example of weather forecast information for each zone. 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 diagram showing a case where a distribution schedule is created in the present invention. Detailed flowchart [Explanation of reference numerals]
DESCRIPTION OF SYMBOLS 1 Communication satellite 2 Center station 3 Satellite transmission means 4 Distribution schedule creation means 5 Reception success rate totaling means according to time zone 6 Ground line receiving means 7 Weather forecast information management means 20 Receiving terminal 21 Satellite reception means 22 Reception history information management means 23 Line transmitting means 30 receiving terminal 31 satellite receiving means 32 reception history information managing means 33 terrestrial line transmitting means

Claims

In a satellite data distribution system that distributes data from a center station to at least one receiving terminal via a communication satellite, each of the receiving terminals includes:
Satellite receiving means for receiving data distributed from the center station;
If the received data is data for reception confirmation, reception history information management means for storing the success or failure of the reception,
Ground line transmission means for transmitting the reception history information stored in the reception history information management means immediately or at predetermined time intervals to the center station by a ground line,
The center station,
To the receiving terminal via the communication satellite, a satellite transmitting means for transmitting the data for reception confirmation at regular time intervals, or data intended for original distribution,
Ground line receiving means for receiving the reception history information collected for the reception confirmation data from the reception terminal,
A time slot-based reception success rate counting means for counting a reception success rate for each time zone based on the received reception history information;
Distribution schedule creation means for creating, for each of the receiving terminals, a delivery schedule concentrated on a time zone having the highest reception success rate based on the reception success rate for each time zone, which is collected by the reception success rate for each time zone,
A satellite data distribution system, wherein the satellite transmitting means transmits the original data for distribution in accordance with the schedule.

In a satellite data distribution system that distributes data from a center station to at least one receiving terminal via a communication satellite, each of the receiving terminals includes:
Satellite receiving means for receiving data distributed from the center station;
If the received data is data for reception confirmation, reception history information management means for storing the success or failure of the reception,
Ground line transmission means for transmitting the reception history information stored in the reception history information management means immediately or at predetermined time intervals to the center station by a ground line,
The center station,
To the receiving terminal via the communication satellite, a satellite transmitting means for transmitting the data for reception confirmation at regular time intervals, or data intended for original distribution,
Ground line receiving means for receiving reception history information collected for the reception confirmation data from the reception terminal,
A time zone-based reception success rate totaling 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;
The distribution schedule concentrated in the time zone with the highest reception success rate is received based on the reception success rate by time zone aggregated by the reception success rate by hour aggregation means and the weather forecast information managed by the weather forecast information management means. Distribution schedule creation means created for each terminal,
A satellite data distribution system, wherein the satellite transmitting means transmits the original data for distribution in accordance with the schedule.

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 1 or 2.

In a satellite data distribution method for distributing data from a center station to at least one receiving terminal via a communication satellite,
A first procedure of transmitting the data for reception confirmation at a fixed time interval from the center station to the receiving terminal via the communication satellite,
A second procedure in which the receiving terminal receives data for reception confirmation distributed from the center station,
A third procedure for storing reception success or failure of the received reception confirmation data;
A fourth procedure of 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;
A fifth procedure of receiving the reception calendar history information collected for the reception confirmation data from the reception terminal;
A sixth procedure for totalizing a reception success rate for each time zone based on the received reception history information;
A seventh procedure of creating, for each of the receiving terminals, a distribution schedule concentrated on the time zone having the highest reception success rate based on the totaled time zone reception success rates;
Satellite data distribution method and having an eighth step of transmitting the data of the original distribution purposes in accordance with the delivery schedule.

In a satellite data distribution method for distributing data from a center station to at least one receiving terminal via a communication satellite,
A first procedure of transmitting the data for reception confirmation at a fixed time interval from the center station to the receiving terminal via the communication satellite,
A second procedure in which the receiving terminal receives data for reception confirmation distributed from the center station,
A third procedure for storing reception success or failure of the received reception confirmation data;
A fourth procedure of 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;
A fifth procedure of receiving the reception calendar history information collected for the reception confirmation data from the reception 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 weather forecast information;
An eighth procedure of creating a distribution schedule concentrated on the time zone having the highest reception success rate for each of the receiving terminals based on the totaled time zone reception success rates and the managed weather forecast information,
Satellite data distribution method and having a ninth step of transmitting the data of the original distribution purposes in accordance with the delivery schedule.

The first and fifth to eighth procedures according to claim 4 or the first and fifth to ninth procedures according to claim 5 are executed by a computer constituting a center station. Item 6. A computer-readable recording medium recording a program for causing a receiving terminal to execute the second to fourth procedures described in Item 5.