• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The invention proposes a very high-speed satellite system complemented by a network cache system based on a station placed on a platform at high altitude, for example an aerostat. The invention has the advantage of allowing a decrease in the required bit rate on the power link without requiring the installation of a cache server on board the satellite.
    公开号:FR3067898A1
    申请号:FR1700644
    申请日:2017-06-15
    公开日:2018-12-21
    发明作者:Jean Didier Gayrard；Walter Zoccarato
    申请人:Thales SA；
    IPC主号:
    专利说明:

    Telecommunications system comprising a cache server embedded in a high altitude platform and associated data transmission method
    The invention relates to the field of very high-speed satellite systems or communication systems for very broadband access to the Internet by geostationary satellite. This domain includes VHTS systems for “Very High Throughput Satellite” in English.
    The invention relates to a telecommunications system comprising a cache server on board a high altitude platform to complement a very high speed satellite system. The invention is useful in Internet access systems with multi-beam coverage and very broadband operating, for example, in Ka band (20/30 GHz) to decongest the feeder link (or "feeder link"). in English) which ensures the transmission between the feed stations (or "feeder station" in English) on the ground and the satellite, of all the information intended for the user terminals.
    In the remainder of the description, the term “station” designates equipment comprising one or more transmitters or receivers, or a set of transmitters and receivers, including accessory devices, necessary to provide a communication service at a given location. .
    A “station placed on a high altitude platform” (HAPS in English for High Altitude Platform Station) means a station installed on an object placed at a high altitude, for example above 18 km and at a specified point, nominal, fixed with respect to Earth. The object may be, for example, an aerostat.
    A “gateway station” designates a station intended to provide a communication link with a station placed on a high altitude platform and to interface a local terrestrial network.
    A "feeder station" means an earth station intended to provide power links with the satellite and to interface the Internet and / or a local terrestrial network.
    In very high-speed satellite systems, the feed link between the ground feed station and the satellite is a bottleneck because all digital data intended for users and from users pass over this link. power supply connecting the power station to the satellite.
    For example, a very high speed satellite system operating in Ka band (20/30 GHz) having a coverage area made up of 200 spots and a bandwidth of 1.4 GHz allocated to each spot, is able to transmit to users on average more than 500 Gbits / second (average spectral efficiency of 1.8 b / s / Hz). The supply link must therefore allow more than 500 Gbits / second to be transmitted to the satellite, which represents a considerable bit rate for a radiofrequency link. The frequency bands allocated to the supply links of geostationary satellites by the International Telecommunication Union (ITU) do not exceed 2 GHz in Ka band (20/30 GHz) and 5 GHz in Q / V band (40/50 GHz).
    There is therefore a problem to be solved in order to reduce the data flow which transits on the supply link so as not to exceed the speed resources available on this link.
    A known solution to solve the drawback associated with excessive demand on the supply link is based on an increase in the bandwidth and / or the data rate of this link. This increase in resources can be done, for example, by a technique of reusing frequencies and polarizations between remote power stations from one another. Thus, a very high-speed satellite system requiring a speed of more than 500 Gbits / second on a Q / V band power link can integrate more than thirty power stations distributed in the coverage area.
    In addition, the radio frequency links in Q / V band through the atmosphere are very sensitive to the attenuation and distortion of signals due to bad weather (rain, snow, hail ...) and consequently these radio frequency links are regularly ineffective. It is necessary to implement a site diversity technique, by installing emergency power stations and connecting them to the other power stations by a terrestrial network. When a radio frequency link from a power station is inoperative due to inclement weather, an emergency power link is activated from a non-weathered emergency power station.
    This solution is very costly in terms of initial investment to install a large number of power stations and connect them to each other by a fiber optic network as well as in terms of operation and maintenance.
    Another solution to avoid overuse of the power supply link is to reduce the data throughput requirement of this connection by a network caching technique (or web caching in English). All the content, and in particular the videos, requested by the users of a very high-speed satellite system pass through the power link. Thus the most popular content is transmitted on the feed link as many times as they were required. Prospective studies show that video traffic will account for 70 to 80% of all Internet traffic in 2020. Measurements on terrestrial network cache systems have shown that caching the most popular videos can reduce traffic. servers at least 50%. By transposing this result to a very high-speed satellite system, a reduction of 50% in the speed requirement of the supply link is possible with the implementation of a network cache system.
    The implementation of a network cache can be done in three locations of the system: in the user terminal, in the power station and in the satellite. Installing a cache server in user terminals has a very small impact on the data rate of the feeder link and is, in general, already implemented in very high speed satellite systems. Installing a network cache system in a power station has no impact on the throughput of the power link. Only the installation of a network cache system on board the satellite can reduce the need for data throughput on the power link.
    An implementation of this solution, consisting in installing a network cache system on board a satellite, has been described in US patent US 6697850 "Satellite-based communication System having an On-board Internet Web Proxy cache". This solution is very complex and expensive because it requires to embark on board the satellite additional and specific equipment such as multi-carrier demodulators to detect requests from user terminals, a proxy server or proxy server. to analyze requests, a cache manager or server and its memory to store and manage content, modulators and multiplexers to transmit hidden content to users, high-speed demodulators to receive content via the feed link hide. The deployment of such a solution has another drawback, namely, the implementation of a new type of more complex and more expensive user terminal.
    In order to overcome the drawbacks of the aforementioned solutions, the invention provides a very high-speed satellite system supplemented by a network cache system based on a station placed on a platform at high altitude, for example an aerostat.
    The invention has the advantage of allowing a reduction in the speed required on the power supply link without the need to install a cache server on board the satellite.
    The subject of the invention is a telecommunications system comprising:
    at least one ground power station with access to at least one remote server,
    - a satellite payload suitable for establishing a first communication link with at least one user on the ground and a second communication link with said at least one power station,
    at least one station placed on a high altitude platform suitable for establishing a third communication link with the satellite payload and comprising a cache server comprising a memory,
    - And at least one ground gateway station configured to communicate said at least one ground power station with said at least one station placed on a platform at high altitude,
    - the telecommunications system being configured to save, in the memory, data, called popular data, coming from the remote server and likely to be required several times by at least one user and retransmit on request to at least one user popular data saved in memory.
    According to a particular aspect of the invention, said at least one ground supply station is configured for:
    - receive at least one request for data from a user,
    - determine if the required data is saved in the memory of a cache server of at least one station placed on a high altitude platform,
    - if the required data are saved in the memory, transmit the request to said at least one station placed on a platform at high altitude,
    - if the required data is not saved in the memory, recover the required data from at least one remote server and determine if the required data are popular data,
    - if the required data are popular data, transmit the required data to at least one station placed on a platform at high altitude,
    - if the requested data is not popular data, transmit the required data to the user via the satellite payload.
    According to a particular aspect of the invention, said at least one station placed on a high altitude platform is configured to receive data to be cached in the memory of the cache server, to receive a request for access to data stored in the cache server memory and transmitting data stored in the cache server memory to at least one user on the ground via the satellite payload.
    According to a particular aspect of the invention, the satellite payload is configured to retransmit to said at least one supply station requests sent by users on the ground, aggregate data or signals transmitted by said at least one station feeding and by said at least one station placed on a platform at high altitude and retransmitting to said users the aggregated data or the aggregated signals.
    According to a particular variant of the invention, the satellite payload comprises:
    - at least a first receiver for receiving a signal transmitted by said at least one supply station and converting the received signal into frequency,
    at least one second receiver for receiving a signal transmitted by said at least one station placed on a high altitude platform, at least one signal aggregation device for frequency multiplexing the signals received by said at least one first receiver and the signals received by said at least one second receiver as a function of the frequency at which they are intended to be retransmitted to a user on the ground,
    - at least one transmitter for retransmitting the signals output from said at least one aggregation device to a user on the ground.
    According to a particular variant of the invention, the satellite payload comprises:
    - at least one first receiver for receiving data transmitted by said at least one supply station,
    - at least one second receiver for receiving data transmitted by said at least one station placed on a platform at high altitude,
    - at least one routing device for multiplexing the data received by said at least one first receiver and the data received by said at least one second receiver according to the user on the ground for which it is intended,
    - at least one signal aggregation device for temporally multiplexing the data coming from said at least one routing device and intended for a user on the ground,
    - at least one transmitter for retransmitting the data output from said at least one aggregation device to a user on the ground.
    According to a particular aspect of the invention, said at least one gateway station and said at least one power station are interconnected by means of a local network or the Internet.
    According to a particular aspect of the invention, said at least one station placed on a high altitude platform and said at least one gateway station are adapted to establish at least one bidirectional radio frequency communication link.
    According to a particular aspect of the invention, said at least one station placed on a high altitude platform and the satellite payload are configured to establish at least one optical communication link in free space.
    According to a particular aspect of the invention, said at least one ground power station and the satellite payload are configured to establish at least one two-way radiofrequency communication link.
    According to a particular aspect of the invention, a stationary high altitude platform is an aerostat equipped with propulsion means to remain stationary around a specified point, nominal and fixed relative to the Earth.
    The invention also relates to a method of transmitting data by means of a telecommunications system comprising at least one ground power station having access to at least one remote server, a satellite payload suitable for establishing a first communication link with at least one user on the ground and a second communication link with said at least one supply station, at least one station placed on a high altitude platform suitable for establishing a third communication link with the payload of satellite and comprising a cache server comprising a memory and at least one ground gateway station configured to communicate said at least one ground power station with said at least one station placed on a platform at high altitude, said method comprising following steps :
    - at least one ground power station receives a request for data from a user,
    - said at least one ground power station determines whether the required data is saved in the memory of a cache server of at least one station placed on a platform at high altitude,
    - If the required data are saved in the memory, said at least one ground supply station transmits the request to said at least one station placed on a high altitude platform which transmits the data saved in memory to at least one user at ground via satellite payload,
    - if the required data are not saved in the memory, said at least one ground supply station recovers the required data from at least one remote server and determines whether the required data are popular data, likely to be required several times by at least one user,
    - if the required data are popular data, said at least one ground power station transmits the required data to at least one station placed on a high altitude platform which caches them in the memory of the cache server and transmits to at least one user on the ground via the satellite payload,
    - if the required data are not popular data, said at least one ground power station transmits the required data to the user via the satellite payload.
    Other characteristics and advantages of the present invention will appear better on reading the description which follows in relation to the appended drawings which represent:
    - Figure 1, a diagram of a communication system for very broadband access to the Internet or very high speed satellite system supplemented by a network cache system according to the invention.
    FIG. 2, a diagram of the flow of a request for content by a user in the system according to the invention,
    FIG. 3, a diagram of the flow of content required by a user in the system according to the invention in the case where the content is cached in the cache server placed on the platform at high altitude,
    - Figure 4, a diagram of the flow of content required by a user in the system according to the invention in the case where the content was not cached,
    - Figure 5, a flowchart of the method for relaying requests and content between equipment and entities of the system according to the invention,
    FIG. 6, a diagram of a satellite payload comprising a transponder according to a first embodiment of the invention,
    FIG. 6bis, a diagram of a satellite payload comprising a transponder according to a second embodiment of the invention,
    FIG. 7, a diagram of a first example of payload placed on a high altitude platform of a system according to the invention corresponding to the first embodiment of FIG. 6,
    - Figure 7bis, a diagram of a second example of payload placed on a high altitude platform of a system according to the invention corresponding to the second embodiment of Figure 6bis,
    - Figure 8, a diagram of an alternative embodiment of the system according to the invention presented in Figure 1.
    FIG. 1 represents an example of a very high-speed satellite system comprising a cache server and its memory installed in a station placed on a platform at high altitude according to an embodiment of the invention.
    In the example of FIG. 1, the system according to the invention comprises a station placed on a high altitude platform SHA equipped with a cache server Svr_Ca comprising a cache memory M. The station SHA is able to communicate from a part with a local terrestrial network RL via a gateway station SP on the ground and secondly with one or more user terminals TU via the satellite SAT.
    The station placed on a high altitude platform SHA is equipped with a transmission device to establish a bidirectional radio frequency link 120,121 with a gateway station SP. The station placed on a high altitude platform SHA is also equipped with a transmission device to establish an optical link in free space or laser link 130 with the SAT satellite. The SHA high altitude platform is, for example, a stratospheric aerostat. It is provided with propulsion means, typically a motor, allowing it to compensate for the force of the winds to remain stationary around a specified point, nominal, fixed relative to the Earth.
    In addition, the system according to the invention comprises at least one gateway station SP capable of communicating on the one hand with the station placed on a high altitude platform SHA and on the other hand with at least one supply station SA via a LAN local network. The SP gateway station is equipped with a transmission device to establish a two-way radio frequency link 120,121 with the station placed on a high altitude platform SHA. The gateway station SP is also connected, via a communication link 301, to the local network RL.
    In addition, the system according to the invention comprises at least one power station SA equipped with a Svr_Py proxy server and capable of communicating on the one hand with the local area network RL and the Internet network INT, and on the other hand with TU user terminals via the SAT satellite. Proxy servers installed on different power stations are networked to communicate with each other. The SA power station is equipped with a transmission device to establish a two-way radio frequency link 101,110 with the SAT satellite. The power station SA is also equipped to establish a communication link 302 with the local network and another communication link 303 with the Internet network. The uplink radio frequency link 110 between the power station SA and the satellite SAT is called the "go" power link and is received by a "go" transponder TAL from the SAT satellite. The downlink radio link 101 between the SAT satellite and the SA power station is called the "return" power link and is transmitted by a TRN "return" transponder from the SAT satellite.
    In addition, the system according to the invention comprises a payload of satellite SAT equipped with one or more “return” TRN transponders capable of establishing a radio link 110 with at least one power station SA and a radio link 111 with user terminals TU, and one or more “forward” TAL transponders capable of establishing a radio link 101 with at least one power station SA, a laser link 130 with at least one station placed on a high altitude platform SHA and a radio link 100 with user terminals TU. A "go" transponder is equipped with a MUX data flow aggregation device which aggregates the data carried by the radio link 110 and by the laser link 130 into a uniform data flow transmitted by the radio link 111.
    In addition, the system according to the invention comprises a local terrestrial network RL which interconnects the supply stations SA and the gateway stations SP. In a particular embodiment of the invention, the terrestrial local area network RL is the Internet network INT.
    In another alternative embodiment of the invention, several stations placed on high altitude platforms SHA each associated with a different gateway station SP, are provided for the same SAT satellite. An advantage of this variant is that it allows better management of the cache memory by benefiting from several cache servers arranged in several stations.
    The system according to the invention described in FIG. 1 makes it possible to cache in a cache server on board a station placed on a platform at high altitude, popular data likely to be required several times by one or more users.
    The term "popular data" is used to refer to data that has a high popularity score, which reflects the likelihood that this data will be requested soon by one or more users. Thus, popular data is data that may be required again in a future time interval of predefined duration.
    The notion of popularity of data or content is used to select the content to be stored and to arbitrate its retention. A popularity score is calculated based on certain criteria. The criteria used are, for example, the frequency of user requests requesting the transmission of content, the time interval between two requests requesting the transmission of identical content, the binary size of a content, the nature content (video, image, sound, text), the age of the content.
    We now describe the operation of the system according to the invention for managing the caching of popular data.
    FIG. 2 represents, on the same example as that of FIG. 1, an example of routing, in the system according to the invention, of a request originating from a user terminal TU.
    At a given time, the user terminal TU generates a content request and transmits it to the proxy server Svr_Py of the power station.
    SA via the TRN “return” transponder of the SAT satellite and the SA power station. The request is carried by the radio links 100 and 101. The proxy server Svr_Py analyzes the request and determines whether the cache server Svr_Ca of the high altitude platform SHA contains a valid copy of the required content in its cache memory M. The example of Figure 2 is limited to a single cache server, however, and as indicated above, several cache servers arranged on several stations placed on different platforms at high altitude can be envisaged. If multiple cache servers coexist, the Svr_Py proxy server is configured to determine if at least one of the available cache servers contains a valid copy of the required content.
    If the Svr_Ca cache server has a copy of the content saved in cache memory, the Svr_Py proxy server transmits the request to the Svr_Ca cache server via the local network RL and the gateway station SP. The request is conveyed by the communication link 302, by the local area network RL, by the communication link 301 and by the radio frequency link 120.
    If the Svr_Ca cache server does not have a cached copy of the content, the Svr_Py proxy server forwards the request to a remote Svr_Di server that stores the content over the Internet. The request is conveyed by the communication link 303 and by Internet.
    FIG. 3 represents an example of the routing of content required by a user terminal TU in the system according to the invention in the case where the content is saved in the memory of the cache server Svr_Ca placed in a platform at high altitude. The cache server Svr_Ca analyzes the request and transmits the required content to the user terminal TU via the “go” transponder TAL of the SAT satellite. The “go” transponder TAL is suitable for aggregating the data transmitted by the station SHA with that transmitted by the supply station SA on the supply link 110. The content is conveyed by the laser link 130 and the radio frequency link 111.
    FIG. 4 represents an example of the routing of content required by a user terminal TU in the system according to the invention in the case where the content is not saved in the memory of the cache server Svr_Ca placed in a high platform. altitude.
    In this case, the remote server Svr_Di transmits the required content to the proxy server Svr_Py of the power station SA via the Internet and the communication link 303. The proxy server Svr_Py of the power station SA analyzes the popularity of the content provided by the Svr_Di remote server and assesses the advantage of caching this content in the memory of the Svr_Ca cache server placed on the platform at high altitude.
    If the content is not popular enough to justify its caching, the Svr_Py proxy server of the feed station SA transmits the required content to the user terminal TU via the "go" transponder TAL of the SAT satellite. The content is carried by the radio frequency links 110,111.
    If the content is popular enough to justify its caching, the proxy server Svr_Py of the feed station SA transmits the content to the cache server Svr_Ca of the platform at high altitude via the local network RL and the gateway station SP. The content is conveyed by the communication link 302, the local area network RL, the communication link 301 and the radio frequency link 120. The cache server Svr_Ca stores the content and transmits the required content to the user terminal TU via the transponder " go »TAL from SAT satellite. The content is conveyed by the laser link 130 and the radio frequency link 111.
    FIG. 5 represents, on a flowchart, the different steps of a method of transmitting data to a user terminal TU using the system according to the invention.
    In a first step 501, a user terminal TU transmits a content request to the proxy server Svr_Py of a supply station SA via a satellite SAT. On receipt of the request, the Svr_Py proxy server analyzes 502 the request to determine whether the required content is available or not in a cache memory of a cache server.
    If the required content is available in a cache memory of a cache server, then the Svr_Py proxy server transmits 503 the request to the cache server Svr_Ca embedded in a high altitude platform SHA. The cache server Svr_Ca then transmits 504 the required content to the user terminal TU via the satellite SAT.
    If the required content is not available in any cache of a cache server, then the Svr_Py proxy server transmits 505 the user's request to a remote Svr_Di server via the Internet. The remote server Svr_Di transmits the required content 506 to the proxy server Svr_Py of the supply station SA via the Internet. The Svr_Py proxy server then analyzes 507 the popularity of the required content.
    If the required content is not considered popular, then the Svr_Py proxy server transmits 508 this content to the user terminal TU via the feed link 110 and the satellite SAT.
    If the required content is considered popular, then the Svr_Py proxy server 509 transmits the content to a Svr_Ca cache server embedded in a high altitude SHA platform for caching. If several cache servers are available, the Svr_Py proxy server selects one of them using, for example, the remaining space available in each cache or the geographical origin of the request. The cache server Svr_Ca stores 510 in its cache memory the content transmitted by the proxy server Svr_Py, informs the proxy server Svr_Py then transmits 511 the content to the user terminal TU via the satellite SAT.
    FIG. 6 represents, in a diagram, an example of an architecture of a “go” transponder TAL of the payload of a satellite SAT of the system according to a first embodiment of the invention.
    A TAL “forward” transponder includes a SAM multibeam antenna system for receiving radio signals from power supply lines transmitted by N different power stations. The SAM multibeam antenna system includes, for example, a separate antenna for each feed link. The TAL transponder also includes several reception devices RECi, REC k , each reception device being associated with a supply link. A reception device RECi, REC k has for function the amplification of the radio signal, the frequency demultiplexing of the signal and the transposition of the signal into frequency on a frequency at which it is intended to be retransmitted on the downlink of the satellite, towards a user terminated on the ground. On the supply link 110, the signals are transmitted according to a predetermined frequency plan. Each frequency or frequency sub-band corresponds in particular to a terrestrial spot comprising several TU terminals. Thus, the signals received by the TAL transponder from the same supply link can include content transmitted on different frequencies, since it is intended for different users. A reception device RECi, REC k therefore has the role of separating the signals received as a function of their frequency on the supply link 110, of transposing the signals to another frequency corresponding to the frequency plane on the downlink 100, then to transmit these signals to a flow aggregating device AGRi, AGRm, AGRi, AGRî + m- For each spot in the coverage area to be covered, a flow aggregating device AGRi, AGR M , AGR ,, AGRî + ma for the function frequency multiplexing of the signals transmitted by the reception device 31 on the one hand and of the signals transmitted by the demux multiplexer DEMUX on the other hand. The multiplexed signals at the output of a flow aggregating device AGRi, AGRm, AGR ,, AGR + m are sent to the user antenna system SAU to be transmitted on the downlink 100.
    The TAL transponder also comprises at least one reception chain associated with an optical link 130 with at least one station placed on a high altitude platform SHA. This reception chain comprises one or more TOP optical terminals capable of receiving the optical signals, one or more optical / electrical ROE receivers capable of converting the optical signals into electrical signals and a DEMUX demultiplexer device capable of demultiplexing the signals received in frequency for the orient towards the AGRi, AGR M , AGR ,, AGR + m flux aggregating devices according to the spot for which they are intended. If several stations placed on a high altitude platform SHA are provided in the system, then the TAL transponder comprises as many reception channels as there are stations.
    FIG. 6a represents, in a diagram, an example of architecture of a “go” transponder TAL of the satellite of the system according to a second embodiment of the invention. In this second embodiment, a TAL “go” transponder always comprises a multibeam antenna system SAM for receiving the radio signals of supply links transmitted by N different supply stations. The SAM multibeam antenna system includes, for example, a separate antenna for each feed link. The TAL transponder also includes several DEMi.DEMr.DEMn reception devices capable of demodulating and decoding the signals received from each supply link. Thus, each reception device demodulates a radio signal to regenerate the digital data streams intended for the user terminals of each spot. The TAL transponder also includes a first router R ^ capable of routing the digital data flows to the various flow aggregator devices AGRi, AGR M , AGR ,, AGR i + M. In this second embodiment, the flows from the feed stations and destined for the different spots are routed as a function of their destination which is obtained directly by demodulating and decoding the flows received and no longer simply on the basis of the plans of respective frequency of the uplink 110 and downlink 100. The TAL transponder thus includes a flux aggregator device for each spot to be covered. Each AGR-i, AGRm, AGR ,, AGR, + m stream aggregating device is capable of temporally multiplexing and synchronizing the data streams coming from the reception devices DEM ^ DEMr.DEMn on the one hand and the streams on the other hand of data coming from the second router RT 2 of the reception chain associated with the high altitude platforms. The multiplexed data streams are transmitted to a TRANS transmission system comprising at least one coder / modulator for modulating the digital data received and a radio transmission chain as well as several user antennas for transmitting the signals generated to the various spots.
    The TAL transponder also comprises at least one reception chain associated with an optical link 130 with at least one station placed on a high altitude platform SHA. This reception chain comprises one or more TOP optical terminals capable of receiving the optical signals, one or more ROE optical / electrical receivers capable of converting the optical signals into electrical signals, one or more DEMOD demodulators for demodulating the electrical signals in order to regenerate the digital data and a second RT 2 router capable of routing the received signals to direct them to the AGR-i, AGR m , AGR ,, AGR. + m flow aggregator devices according to the spot for which they are intended. The destination of a stream is determined by analysis of the demodulated digital data, this destination corresponding for example to the destination network address of the data packets. In an alternative embodiment of the invention, the first RT-i router and the second RT router 2 are merged into a single RT router.
    FIG. 7 represents, on a diagram, an example of payload of a station placed on a platform at high altitude according to a first embodiment of the invention corresponding to the mode described in FIG. 6.
    The payload 700 comprises at least a first gateway station access payload 710 for communicating with a ground gateway station SP. The first payload 710 comprises at least one antenna 711, a receiver 712 and a transmitter 713. The payload 701 also includes a cache server and a memory 720. The receiver 712 is able to save data in the memory of the cache server .
    The payload 700 further includes a second satellite access payload 730 for communicating with a TAL “go” transponder of a SAT satellite. This second payload 730 comprises at least one radio modulator 733 capable of recovering digital data in the memory of the cache server 720 and of modulating this data to generate a radio signal. The radio modulator 733 is also configured to transpose the radio signal to a frequency band corresponding to the destination spot of the data, in the frequency plane of the downlink 100 from the SAT satellite to the user terminals TU. The second payload 730 also includes an opto-electric modulator 731 capable of converting the radio signal into an optical signal, and an optical terminal 732 for transmitting the optical signal to the SAT satellite.
    FIG. 7bis represents, on a diagram, an example of payload 800 of a station placed on a platform at high altitude according to a second embodiment of the invention corresponding to the mode described in FIG. 6bis. In this second embodiment, the radio modulator 733 is eliminated because it is not necessary to transpose the signal to a frequency band corresponding to a destination spot because the optical signal generated is completely demodulated on board the satellite to recover the data and deduce the address of the destination spot.
    Figure 8 shows schematically an alternative embodiment of the system according to the invention presented in Figure 1. In this variant, the local network RL is replaced by the Internet network INT. In this case, a gateway station further comprises an auxiliary server Svr_Ax able to interface the gateway station with the Internet network INT. The gateway station SP is controlled by a power station SA via the internet network INT.
    权利要求:
    Claims (12)
    [1" id="c-fr-0001]
    1. Telecommunications system comprising:
    at least one ground supply station (SA) having access to at least one remote server (Svr_Di),
    - a satellite payload (TAL) adapted to establish a first communication link (100,111) with at least one ground user (TU) and a second communication link (101,110) with said at least one station food (SA),
    - at least one station placed on a high altitude platform (SHA) adapted to establish a third communication link (130) with the satellite payload (TAL) and comprising a cache server (Svr_Ca) comprising a memory (M),
    - And at least one ground gateway station (SP) configured to communicate said at least one ground power station (SA) with said at least one station placed on a high altitude platform (SHA),
    - the telecommunications system being configured to save, in the memory (M), data, called popular data, coming from the remote server (Svr_Di) and likely to be required several times by at least one user (TU) and retransmit on request to at least one user (TU) popular data saved in the memory (M).
    [2" id="c-fr-0002]
    2. The telecommunications system as claimed in claim 1, in which said at least one ground supply station (SA) is configured for:
    - receive at least one user data request (TU),
    - determine if the required data is saved in the memory (M) of a cache server (Svr_Ca) of at least one station placed on a high altitude platform (SHA),
    - if the required data are saved in the memory (M), transmit the request to said at least one station placed on a high altitude platform (SHA),
    - if the required data are not saved in the memory (M), recover the required data from at least one remote server (Svr_Di) and determine if the required data are popular data,
    - if the required data are popular data, transmit the required data to at least one station placed on a high altitude platform (SHA),
    - if the required data are not popular data, transmit the required data to the user (TU) via the satellite payload (TAL).
    [3" id="c-fr-0003]
    3. The telecommunications system as claimed in claim 1, in which said at least one station placed on a high altitude platform (SHA) is configured to receive data to be cached in the memory (M) of the cache server ( Svr_Ca), receive a request for access to data stored in the memory (M) of the cache server (Svr_Ca) and transmit data stored in the memory (M) of the cache server (Svr_Ca) to at least one user at ground (TU) via satellite payload (TAL).
    [4" id="c-fr-0004]
    4. Telecommunications system according to claim 1, in which the satellite payload (TAL) is configured to retransmit to said at least one power station (SA) requests sent by users on the ground ( TU), aggregate data or signals transmitted by said at least one power station (SA) and by said at least one station placed on a high altitude platform (SHA) and retransmit to said users (TU) the aggregated data or aggregated signals.
    [5" id="c-fr-0005]
    5. Telecommunications system according to one of the preceding claims, in which the satellite payload (TAL) comprises:
    - at least one first receiver (RECi, .. REC k ) for receiving a signal transmitted by said at least one supply station (SA) and converting the received signal into frequency,
    - at least one second receiver (ROE) for receiving a signal transmitted by said at least one station placed on a high altitude platform (SHA), at least one device (AGRi, .. AGRm, ... AGR .... ........
    signal aggregation for frequency multiplexing the signals received by said at least one first receiver (RECi, .. REC k ) and the signals received by said at least one second receiver (ROE) as a function of the frequency at which they are intended to be retransmitted towards a user on the ground (TU),
    - at least one transmitter (SAU) for retransmitting the signals at the output of said at least one aggregation device (AGR-i, .. AGRm, ... AGR to a ground user (TU).
    [6" id="c-fr-0006]
    6. Telecommunication system according to one of claims 1 to 4 in which the satellite payload (TAL) comprises:
    - at least one first receiver (DEMi, ... DEM k , ... DEM N ) for receiving data transmitted by said at least one supply station (SA),
    - at least one second receiver (ROE.DEMOD) for receiving data transmitted by said at least one station placed on a high altitude platform (SHA),
    - at least one routing device (RTi, RT2) for multiplexing the data received by said at least one first receiver (DEM-i, ... DEMi <, ... DEMn) and the data received by said at least one second receiver (ROE.DEMOD) according to the user on the ground for which they are intended,
    - at least one device (AGRi, .. AGRM „.. AGRi, ... AGRi + M) for signal aggregation to temporally multiplex the data coming from said at least one routing device (RT 1 , RT 2 ) and intended to a ground user,
    - at least one transmitter (TRANS) for retransmitting the data output from said at least one aggregation device (AGRi, .. AGRm „.. AGR to a user on the ground.
    [7" id="c-fr-0007]
    7. The telecommunications system as claimed in claim 1, in which said at least one gateway station (SP) and said at least one power station (SA) are interconnected by means of a local area network (RL) or of the network. Internet (INT).
    [8" id="c-fr-0008]
    8. The telecommunications system as claimed in claim 1, in which said at least one station placed on a high altitude platform (SHA) and said at least one gateway station (SP) are adapted to establish at least one radiofrequency communication link. bidirectional (120,121).
    [9" id="c-fr-0009]
    9. The telecommunications system as claimed in claim 1, in which said at least one station placed on a high altitude platform (SHA) and the satellite payload (TAL) are configured to establish at least one communication link. free space optical communication (130).
    [10" id="c-fr-0010]
    10. The telecommunications system as claimed in claim 1, in which said at least one ground power station (SA) and the satellite payload (TAL) are configured to establish at least one bidirectional communication link. radio frequency (101,110).
    [11" id="c-fr-0011]
    11. Telecommunications system according to claim 1, in which a stationary high altitude platform (SHA) is an aerostat equipped with propulsion means to remain stationary around a specified point, nominal and fixed relative to the Earth.
    [12" id="c-fr-0012]
    12. Method for transmitting data by means of a telecommunications system comprising at least one ground power station (SA) having access to at least one remote server (Svr_Di), a satellite payload (TAL) ) adapted to establish a first communication link (100,111) with at least one ground user (TU) and a second communication link (101,110) with said at least one supply station (SA), at least one station placed on a suitable high altitude platform (SHA) for establishing a third communication link (130) with the satellite payload (TAL) and comprising a cache server (Svr_Ca) comprising a memory (M) and at least one ground gateway station (SP) configured to communicate said at least one ground supply station (SA) with said at least one station placed on a high altitude platform (SHA), said method comprising the following steps :
    - at least one ground supply station (SA) receives (501) a user data request (TU),
    - Said at least one ground supply station (SA) determines (502) whether the required data are saved in the memory (M) of a cache server (Svr_Ca) of at least one station placed on a platform high altitude (SHA),
    - if the required data are saved in the memory (M), said at least one ground supply station (SA) transmits (503) the request to said at least one station placed on a high altitude platform (SHA) which transmits (504) the data saved in memory (M) to at least one user on the ground (TU) via the satellite payload (TAL),
    - if the required data are not saved in the memory (M), said at least one ground supply station
    5 (SA) retrieves (505,506) the required data from at least one remote server (Svr_Di) and determines (507) if the required data are popular data, likely to be requested several times by at least one user (TU )
    - if the data required is popular data, said at
    10 at least one ground supply station (SA) transmits (509) the required data to at least one station placed on a high altitude platform (SHA) which caches them (510) in the memory (M) of the server cache (Svr_Ca) and transmits them to at least one ground user (TU) via the satellite payload (TAL)
    15 (SAT),
    - if the required data are not popular data, said at least one ground supply station (SA) transmits (511) the required data to the user (TU) via the satellite payload (TAL) ).
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    同族专利:
    公开号 | 公开日
    AU2018204230A1|2019-01-17|
    EP3416302A1|2018-12-19|
    EP3416302B1|2020-07-22|
    US20180367638A1|2018-12-20|
    FR3067898B1|2019-07-26|
    US10673974B2|2020-06-02|
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    法律状态:
    2018-12-21| PLSC| Publication of the preliminary search report|Effective date: 20181221 |
    2020-05-26| PLFP| Fee payment|Year of fee payment: 4 |
    2021-05-27| PLFP| Fee payment|Year of fee payment: 5 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1700644|2017-06-15|
    FR1700644A|FR3067898B1|2017-06-15|2017-06-15|TELECOMMUNICATIONS SYSTEM COMPRISING AN ON-BOARD CACHE SERVER IN A HIGH-ALTITUDE PLATFORM AND METHOD FOR TRANSMITTING DATA THEREOF|FR1700644A| FR3067898B1|2017-06-15|2017-06-15|TELECOMMUNICATIONS SYSTEM COMPRISING AN ON-BOARD CACHE SERVER IN A HIGH-ALTITUDE PLATFORM AND METHOD FOR TRANSMITTING DATA THEREOF|
    EP18176814.4A| EP3416302B1|2017-06-15|2018-06-08|Telecommunication system comprising a cache server on-board a high-altitude platform and associated data-transmission method|
    US16/007,965| US10673974B2|2017-06-15|2018-06-13|Telecommunication system comprising a cache server located on board a high-altitude platform and associated data-transmitting method|
    AU2018204230A| AU2018204230A1|2017-06-15|2018-06-14|Telecommunication system comprising a cache server located on board a high-altitude platform and associated data-transmitting method|
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