• 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:
    Satellite communication system comprising at least a first ground station 20 and a first satellite 30 and a second satellite 40. The first satellite 30 is thereby active in a first part of a frequency spectrum with a first polarization and with a second polarization. The second satellite 40 is thereby active in a second part of the frequency spectrum with the first polarization and with the second polarization. When one of the satellites 30, 40 is unable to operate, the remaining satellite is active over both the first and the second part of the frequency spectrum.
    公开号:BE1020115A5
    申请号:E201100117
    申请日:2011-02-21
    公开日:2013-05-07
    发明作者:Dirk Breynaert；Frederik Simoens
    申请人:Newtec Cy N V；
    IPC主号:
    专利说明:

    SATELLITE COMMUNICATION SYSTEM WITH REDUNDANCE
    TECHNICAL FIELD OF THE INVENTION
    The present invention relates to satellite communication systems and to methods of using the latter, as well as to elements of such systems, such as base stations and satellites.
    BACKGROUND OF THE INVENTION
    Satellite communication systems with multi-spot coverage are used to provide services such as mobile telephony and broadband services. In such services, the bundles are described as multi-color bundles. The term "multi-color" refers, for example, to the use of different frequency bands and / or different polarizations to minimize interference between nearby spots. All spots are assigned the same frequency, while the same polarizations are assumed to have the same color.
    Figure 1 shows an example of a spot beam configuration with 4 different colors, spots that are geographically spread over a coverage area. Each color is reused in geographically different spots. Each color is a combination of a frequency range and of a polarization. Figure 2 shows a possible transponder frequency plane for the 4-color scheme according to Figure 1. There are four different frequency / polarization combinations: L1, R1, L2, R2, L1, and R1 are assigned to two bundles with the same frequency , but with different polarizations. L2 has the same polarization as L1, but has a different frequency range. R2 has the same frequency range as L2, and the same polarization as R1.
    In order to ensure a virtually uninterrupted service, even in cases where a satellite fails, the satellite communication system can be implemented as a redundant system that uses two satellites. Each satellite is able to set up the connection independently (forward and back).
    "Digital Divide: the Satellite Offer (DDSO)", European Space Research and Technology Center (ESTEC), May 22, 2006, describes a satellite communication system with two co-co-located satellites. The two satellites have different number of bundles (72 and 100). Both satellites work over the same frequency band, but work with different polarizations. One of the satellites uses a left-handed circular polarization (left hand circular polarization - LHCP), while the other uses a right-handed circular polarization (right hand circular polarization - RHCP). When one of the satellites fails, the other polarization is activated in the remaining active satellite, in such a way that the remaining satellite broadcasts using both polarizations.
    SUMMARY OF THE INVENTION
    It is an object of the present invention to provide an alternative solution to provide redundancy in a satellite communication system.
    A first aspect of the invention provides a method for using a satellite communication system that comprises at least a first ground station and a first satellite and a second satellite that are at least partially responsible for the same coverage area, the method comprising: ensuring that the first satellite operates in a first part of a frequency spectrum with a first polarization and with a second polarization; ensuring that the second satellite is active in a second part of the frequency spectrum at the first polarization and at the second polarization; and when one of the satellites is unable to work, ensuring that the remaining satellite is active over both the first and the second part of the frequency spectrum.
    In the case of normal operation, both satellites function until either of them fails. A portion (e.g., half) of the available bandwidth is provided by the first satellite, while the remainder of the available bandwidth is provided by the second satellite. This contrasts with a situation where one satellite takes over the operation of the other, in the event that the other fails (for example, one satellite functional and the other in standby). This offers the advantage that one satellite continues to provide terminal services, and this even after the other satellite has failed. An additional advantage is that the system can use more efficient modulation schemes with a higher spectral efficiency compared to conventional standby solutions in which one satellite is operational, while the standby satellite makes no contribution to the total power.
    All steps of the method can be performed by a control unit in a ground station, or by another control entity of the system.
    The first satellite and the second satellite at least partially ensure coverage of the same coverage area, and can ensure the same coverage area.
    Preferably, the satellites are multi-beam satellites, wherein the first satellite is provided with a plurality of first bundles, and the second satellite is equipped with a plurality of second bundles. Each bundle serves a spot on the ground corresponding to a geographical zone. The satellites operate a spot with a first bundle of the first satellite, and with a second bundle of the second satellite, that is, a spot "sees" two bundles of different satellites. The first satellite uses the first beam by using the first part of the frequency spectrum and one of the two first and second polarizations. The second satellite uses the second bundle by using the second part of the frequency spectrum and the same polarization as that used by the first bundle.
    Preferably, different data is transmitted by the bundle of the first satellite and by the bundle of the second satellite, both of which serve a particular spot.
    Preferably, the satellite communication system provides point-to-multipoint communications, or point-to-point communications.
    Preferably, the first part of the frequency spectrum is adjacent to the second part of the frequency spectrum. This is particularly efficient in terms of frequency usage in the event that one of the satellites fails, the remaining satellite then operating over a continuous frequency range.
    Preferably, the first and second polarizations are circular polarizations (left-turning circular polarizations, right-turning circular polarizations), although other types of polarizations can be used, such as horizontal / vertical polarizations.
    Additional aspects of the invention provide an apparatus for performing the method, while a specific aspect of the invention provides an apparatus for controlling the operation of satellite communication systems comprising a first satellite and a second satellite that are at least partially responsible for the same coverage area, wherein the apparatus comprises a processing apparatus that is provided to perform the method according to the described or claimed method.
    Another aspect of the invention provides a ground station for use in a satellite communication system comprising at least a first satellite and a second satellite which are at least partially responsible for the same coverage area, comprising: an interface for supporting a first forward communication connection with the first satellite for the retransmission by the first satellite, and for supporting a second forward communication link with the second satellite for the retransmission by the second satellite; a control unit that is provided to: ensure that the first satellite is operative in a first portion of a frequency spectrum, by generating the first forward communication link, in such a way that, when a retransmission takes place by the first satellite, a first part of the frequency spectrum is taken with a first polarization and with a second polarization; and ensuring that the second satellite operates in a second portion of a frequency spectrum, by generating the second forward communication link, such that when a second transmission takes place through the second satellite, a second portion of the frequency spectrum is occupied at the first polarization and at the second polarization, and, if one of the satellites is unable to function, generating the forward communication link for the remaining satellite in such a way that, when there is a retransmission takes place by the remaining satellite, both the first part and the second part of the frequency spectrum are occupied.
    An additional aspect of the invention provides a first ground station for use in a satellite communication system that comprises at least a first satellite and a second satellite, as well as a second ground station that can be used, comprising: an interface for supporting a first forward communication connection with the first satellite for retransmission by the first satellite; a control unit that is provided to: ensure that the first satellite is operative in a first portion of a frequency spectrum, by generating the first forward communication link, in such a way that, when a retransmission takes place by the first satellite, a first part of the frequency spectrum is taken with a first polarization and with a second polarization; wherein the satellite communication system also comprises a second ground station for supporting a second forward communication link with the second satellite for retransmission by the second satellite which, when retransmission takes place by the second satellite, occupies a second part of the frequency spectrum at the first polarization and with the second polarization; and, when the second satellite is unable to function, generates the forward communication link in such a way that, when a retransmission takes place by the first satellite, both the first part and the second part of the frequency spectrum are occupied .
    An additional aspect of the invention provides a satellite communication system, comprising at least one ground station that can be used with a first satellite and with a second satellite that are at least partially responsible for the same coverage area, the system comprising: first means provided therein causing the first satellite to operate in a first part of a frequency spectrum with a first polarization and with a second polarization; second means that cause the second satellite to operate in a second part of the frequency spectrum at the first polarization and at the second polarization, and wherein the first and second means are adjusted such that when one of the satellites is unable to To function, the remaining satellite is active over both the first part and the second part of the frequency spectrum.
    The satellites may be multi-bundle satellites, the first satellite having multiple first bundles and the second satellite having multiple second bundles, each bundle serving a particular spot, and the satellites operating a spot with a first bundle of the first satellite and with a second bundle of the second satellite, wherein, for each spot: the first means cause the first satellite to use the first bundle in the first part of the frequency spectrum, and one of the first and second polarizations, the second means for causing the second satellite to use the second beam in the second part of the frequency spectrum, using the same polarization as the first beam.
    Since the satellites may be multi-bundle satellites, the first satellite may have multiple first bundles and the second satellite may have multiple second bundles, each bundle serving a particular spot, and the satellites serving a spot with a first bundle of the first satellite and with a second bundle of the second satellite, where, for each spot: the first means cause the first satellite to use the first beam in the first part of the frequency spectrum, and both first and second polarizations, the second means there ensuring that the second satellite uses the second bundle in the second part of the frequency spectrum, using both first and second polarizations.
    The second part of the frequency spectrum can be located next to the first part of the frequency spectrum.
    Optionally, the satellites operate in the first and second parts by operating around a central frequency, and, if one of the satellites is unable to function, means may be provided that cause the remaining satellite to operate over both the first and the second part of the frequency spectrum, changing the center frequency around which the remaining satellite operates.
    In addition, means may be provided that cause the remaining satellite to drive up a symbol rate for a signal sent by the remaining satellite over the first and the second portion of the frequency spectrum. The symbol rate for the signal transmitted by the remaining satellite over the first and the second portion of the frequency spectrum can be substantially equal to the combined data rate of signals sent separately by the first satellite and the second satellite.
    Optionally, the first part of the frequency spectrum and the second part of the frequency spectrum have the same bandwidth.
    Alternatively, the first part of the frequency spectrum and the second part of the frequency spectrum can have a different bandwidth. There may be several first parts of the frequency spectrum and several second parts of the frequency spectrum. The multiple first parts of the frequency spectrum and the multiple second parts of the frequency spectrum can be interwoven.
    The system may include a first ground station, the first ground station including a first forward communication link with the first satellite for retransmission by the first satellite, as well as a second. forward communication link with the second satellite for retransmission by the second satellite, wherein the first means that cause the first satellite to operate in a first part of the frequency spectrum may include means for generating the first forward communication link, namely on in such a way that, when a retransmission takes place through the first satellite, a first portion of the frequency spectrum is occupied with a first polarization and with a second polarization; and wherein the second means that cause the second satellite to operate in a second portion of the frequency spectrum may include means for generating the second forward communication link, such that when a retransmission takes place through the second satellite, a second part of the frequency spectrum is occupied with the first polarization and with the second polarization. When one of the satellites is unable to function, means are provided for generating the forward communication link for the remaining satellite in such a way that, when there is a retransmission by the remaining satellite, both the first satellite part if the second part of the frequency spectrum is taken.
    Alternatively, it may be provided that a system comprises a first ground station and a second ground station, the first ground station being provided with a first forward communication link with the first satellite for retransmission by the first satellite, and the second ground station being provided with a second forward communication link with the second satellite for retransmission by the second satellite, wherein: the first means for causing the first satellite to operate in a first part of the frequency spectrum may comprise means for generating the first forward communication link, namely on a such that when a retransmission takes place through the first satellite, a first portion of the frequency spectrum is occupied with a first polarization and with a second polarization; the second means for causing the second satellite to operate in a second part of the frequency spectrum may include means for generating the second forward communication link, such that when a retransmission takes place through the second satellite , a second part of the frequency spectrum is taken with a first polarization and with a second polarization; and wherein, if one of the satellites is unable to function, means are provided for generating the forward communication link for the remaining satellite, such that when a retransmission takes place through the remaining satellite, both the first part if the second part of the frequency spectrum is taken.
    The functionality described here can be implemented in hardware or by means of a combination of hardware and software that is executed by a processing device. The processing device may be a computer, or a processor, a state machine, a logic circuit, or any other suitable processing device. The processing device may be a general processor that executes software that causes the general processor to perform the required tasks, or the processing device may be specifically intended to perform the required functions. An additional aspect of the invention provides machine-readable instructions (software) which, when executed by a processor, perform any of the methods described. The machine-readable instructions can be stored in an electronic memory device, on a hard disk, on an optical disk, or in any other machine-readable storage medium. The machine-readable instructions can be downloaded to the storage medium via a network connection.
    BRIEF DESCRIPTION OF THE DRAWINGS
    Embodiments of the present invention will be described by way of example with reference to the accompanying drawings in which:
    Figure 1 is a representation of a four-color bundle configuration in a satellite communication system;
    Figure 2 is a representation of a transponder allocation scheme for Figure 1;
    Figures 3A-3C depict the spectrum assignment for two satellites, in accordance with an embodiment of the invention;
    Figure 4 gives a representation of the spectrum assignment, following the failure of one of the satellites, or for deploying a second satellite;
    Figures 5A-5D shows a first configuration of the spectrum assignment;
    Figures 6A and 6B represent a second configuration of the spectrum assignment;
    Figures 7A and 7B represent a third configuration of the spectrum assignment;
    Figures 8A and 8B represent a fourth configuration of the spectrum assignment;
    Figure 9 shows an embodiment of an apparatus in the satellite communication system;
    Figure 10 shows the frequency translation of forward communication links;
    Figure 11 shows a method for checking the operation of the satellite communication system;
    Figure 12 shows a further embodiment of the device in the satellite communication system.
    DESCRIPTION OF THE PREFERRED EMBODIMENTS
    The present invention will be described with reference to specific embodiments and with reference to the drawings, without, however, the invention being limited thereto. The invention is only defined by the claims. The described drawings are only schematic representations and have no limiting character whatsoever. In the drawings, the dimensions of certain elements may be exaggerated and these elements may not be drawn to scale for illustrative purposes. In cases where the term "comprising" is used in the present description, this does not mean that other elements or steps are excluded. In addition, terms such as "the first", "second", "third", and the like are used in the description and in the claims to distinguish between similar elements and not necessarily for giving a description of a sequential or a chronological order. It should be understood that the terms thus used are interchangeable in the appropriate circumstances, and that the embodiments of the invention described herein may be used in sequences other than those described or illustrated herein.
    Figures 3A - 3B show representations of possible spectrum assignments, in accordance with embodiments of the invention. In each of these drawings, a trapezoidal shape represents either a single modulated carrier, or a combination of two or more modulated carriers with different frequencies that together become the bandwidth indicated by the trapezoidal shape.
    Figure 3A shows a first example of a spectrum assignment for a communication system with two satellites A and B. Satellite A is assigned Lia, Ria, L2a, R2a. Lia and Rla occupy the same part f1 -> f2 of the frequency ie band and have different polarizations, Lia possessing a left-handed circular polarization (Left-Hand Circular Polarization - LHCP) and Ria possessing of a right-handed circular polarization (RHCP). L2a and R2a occupy the same part f3 -> f4 of the frequency band and have different polarizations, L2a having a left-turning circular polarization (LHCP) and R2a having a right-turning circular polarization (RHCP) ). Lia, Ria have an offset f2 -> f3 relative to L2a, R2a.
    Satellite B is assigned Llb, Rib, L2b, R2b. Lia and Rla occupy the same portion f3 -> f4 of the frequency band and have different polarizations, Llb having a left-turning circular polarization (LHCP) and Rib having a right-turning circular polarization (RHCP) ). L2b and R2b occupy the same part f4 -> f5 of the frequency band and have different polarizations, L2b having a left-turning circular polarization (LHCP) and R2b having a right-turning circular polarization (RHCP) ). In Figure 3, the parts all have the same bandwidth, i.e. (f 1 -> f 2) = (f 3 -> f 4) = (f 4 -> f 5). This is a symmetrical award. It is also possible to configure an asymmetric assignment where the parts assigned to satellite A have a bandwidth that is different from the parts assigned to satellite B, i.e. (f1 -> f2)> (f3 - > f4) and (f3 -> f4) <(f4 -> f5). The 125 MHz bandwidth is given by way of example and has no limiting character. Figure 3B shows the spectrum assignment for satellite A. Figure 3C shows the spectrum assignment for satellite B. This spectrum assignment is used on the forward link.
    The two satellites A, B serve four geographical spots in a coverage area. Each spot is served by two bundles: a first bundle of satellite A and a second bundle of satellite B. Spectrum width is allocated in such a way that each spot is served by two bundles that use adjacent parts of the frequency band and the same polarization. Spot L1 is served by Lia of satellite A and by Llb of satellite B, spot R1 is served by Rla of satellite A and by Rib of satellite B, and so on. In normal operation, a terminal will receive signals from both satellites. The recycling pattern that can be found in figure 1 can be used.
    Let us now assume that the operation of satellite A fails. This means that terminals within a certain spot will only receive one bundle and half of the available spectrum will no longer be used. For example, if satellite B fails, only the spectrum that is shown in Figure 3A is used. The signal sent by the remaining functioning satellite is changed in such a way that it occupies the spectrum assigned to satellite A as well as the spectrum assigned to satellite B. This can be achieved, for example, by changing the center frequency from the carriers of satellite A, and also by increasing the symbol speed. For example, doubling the symbol rate will bring the total symbol rate back to the value of the situation in which both satellite A and satellite B were operating.
    Figure 4 shows the spectral allocation after one of the satellites failed, the remaining satellite being modified to make use of the full spectrum. A scenario where satellite B fails can easily be achieved by replacing satellite A with satellite B in this procedure.
    The spectrum assignment that can be found in Figure 4 can also be used at the start of the operation, that is, when satellite A is already launched and operational while satellite B is not yet operational.
    Figures 3A-3C and Figure 4 show a spectrum allocation scheme in which spectrum is assigned to satellite A that is immediately adjacent to the spectrum that is assigned to satellite B. This is particularly efficient in terms of the use of the frequencies because, in the event that one of the satellites fails, the remaining satellite functions over a continuous range of frequencies. In other embodiments of the invention, however, the spectrum assigned to satellite A is not immediately adjacent to the spectrum assigned to satellite B.
    During normal operation (both satellites operational), the solution according to the present invention offers the advantage of having twice the available power to cover the available bandwidth, resulting in a C / N value at the input of the remote receiver of the terminal that is approximately 3dB higher. This is because all Traveling Wave Amplifier Tubes (TWTA) of an operational satellite are always active. This is in contrast to the conventional solution where half of the available resources are inactive and in the waiting state to take over from the other satellite at the time it would fail. Since the forward link is usually limited in terms of downlink power, this will allow the system to use more efficient modulation schemes (higher spectral efficiency) compared to a conventional standby solution where only one satellite is operational, while the standby satellite does not contribute to the total power.
    The described embodiment has four spots (one for each color). It goes without saying that the four-color pattern can be reused over a coverage area in order to serve a larger number of geographical spots. The spectrum assignment can have a greater number of colors than the one shown. In each of these figures, the inputs on the left-hand side of the figure represent the spectrum assignment of the forward link to the satellite (or to the pair of satellites), while the output on the right-hand side of the figure represents the spectrum assignment to separate beams on the forward connection of the satellite (or of the pair of satellites).
    Figures 5A-5B show a number of possible configurations of frequencies, polarizations, and Traveling Wave Tube Amplifiers (TWTA) for a single satellite and for two satellites.
    Figures 5A-5D represent a first configuration. Figure 5A shows a single satellite operation. This can show the assignment after a second satellite has failed, or the operation before a second satellite is operational. Frequency bands may or may not be adjacent to each other, and this up to the available bandwidths of the TWTAs. In a typical transponder scheme, the low band (LL1 and LL2) applied to TWTA low, and the high band (LH1 and LH2) applied to TWTA high can be separated in frequency, as shown in Figure 5A, or they may be situated next to each other in terms of frequency. The outputs to each bundle are shown on the right-hand side of the figure. The frequency parts LL1, RL1 can be located immediately next to the frequency parts LL2, RL2, as shown in figure 5A, or they can have an offset with respect to each other, as shown in figure 5B. The configuration that can be found in figure 5A is more efficient in terms of frequency use.
    Figure 5C shows a different configuration with a single satellite. LL and LH have different bandwidths, while RL and RH also have different bandwidths, that is, an asymmetrical configuration. Some carriers can also be used in every TWTA. An effect that is closer to saturation than with double or multiple carriers is then possible. If there is only a single modulated carrier per transponder, there is no question of intermodulation effects due to the non-linearity. With two or more modulated carriers per transponder, the operating point of the transponder is selected further away from the saturation (higher Input BackOff) in order to limit the intermodulation effects.
    Figure 5D shows an operation with two satellites. The spectrum assignment according to figure 5A is divided over two satellites: satellite A and satellite B. This allows higher power densities in the user terminals compared to figure 5A because each TWTA amplifies a single frequency band instead of two frequency bands as in figure 5A. When one of the satellites fails, the remaining satellite functions as shown in Figure 5A. There are no spots that work with both polarizations. The result is good insulation against cross-polarization. A relatively limited number of terminals at the edges of the bundles will run the risk of interference.
    Figures 6A and 6B represent a second configuration with half the number of TWTAs. Figure 6B shows the operation with two satellites. When one of the satellites fails, the remaining satellite functions as shown in Figure 6A.
    Figure 7A and Figure 7B represent a third configuration. A specific spot (for example spot 1) receives signals from two satellites in adjacent frequency bands. Each satellite broadcasts with both polarizations in each spot. This increases cross-polarization interference with users in the same spot.
    Figures 8A and 8B represent a fourth configuration. This is similar to that of Figures 7A and 7B, but offers the advantage of fewer TWTAs per transponder, and the disadvantage of a more limited power spectral density because the nominal power of a TWTA can normally be considered the same for all implementations.
    Although the configurations shown in Figs. 7A-7B have the disadvantage of having both polarizations in each spot, resulting in high cross-polar interference, they do have the advantage that each terminal can function in any spot, a fact that for example, may be useful for terminals used on a train, or in cases where a terminal is moved from one spot to another. This advantage is achieved because each spot is always "exposed" by both polarizations, both during normal operation and when an error occurs.
    Figure 9 shows a more detailed representation of an embodiment of the satellite system. The system comprises a ground station 20 and satellites 30, 40. The ground station 20 is provided with a network interface 22 to receive traffic intended for terminals within the satellite system, as well as to send traffic received from the terminals within the satellite system. A switching function 23 divides the traffic to output ports corresponding to the two satellites 30, 40. A transmitting / receiving unit 25 supports an RF interface with each satellite via antennas 27. Each RF interface comprises a forward communication link 28A and a recurring communication link 29A . The transmitting / receiving unit 25 performs a coding and a modulation on the traffic. The transmitting / receiving unit 25 can make a selection between a series of possible coding and modulation schemes. A control unit 24 controls the operation of the satellites 30, 40 and receives status data regarding the number of operational satellites. This status data can be received from a control unit 35 in each of the satellites 30, 40.
    Each satellite 30, 40 is provided with an RF interface 32 that supports forward links 28A and reverse links 29A to and from the ground station 20. A switching function 33 and a control unit 35 are provided. A transmitting / receiving unit 37 provides coverage in the form of multiple spot beam zones. The transmit / receive unit 37 supports a forward link 39 and a reverse link to and from each spot beam zone.
    The control unit 24 in the ground station 20 can be implemented in the form of a processing device comprising a computer, a processor, a state machine, a logic circuit, or any other suitable processing device. The processing device may be a general processor that executes software that causes the general processor to perform the required tasks, or the processing device may be a device specifically aimed at performing the required functions.
    In a preferred embodiment, each satellite 30, 40 is provided to receive a forward communication link signal 28A, 28B, respectively, to shift the frequency of the forward link signal, to amplify the signal, and to resend the amplified and shifted signal in the form of a respective downlink signal (for example, a downlink signal 39 is displayed for satellite A) in a coverage area, such as a spot. The shift, gain, and retransmission are performed by units 32, 33, 37. The ground station 20 generates a forward link signal 28A for satellite 30 in such a way that when the frequency is shifted (by means of the known frequency shift as used by satellite 30) and again a transmission takes place by satellite 30, parts of the frequency spectrum as prescribed by the allocation scheme will be taken. Similarly, the ground station 20 will generate a forward link signal 28B for satellite 40 in such a way that when the frequency is shifted (by means of the known frequency shift as used by satellite 30) and a retransmission takes place by satellite 40, parts of the frequency spectrum as required by the allocation scheme will be taken. Figure 10 shows the frequency shift for two satellites. A forward link signal 28A containing signals in assigned portions of the frequency spectrum (e.g., Lia, Ria, L2a, R2a) is received in satellite A and shifted in a manner that maintains the mutual frequency ratio of the signals. Similarly, a forward link signal 28B containing those signals in assigned portions of the frequency spectrum (e.g., L1b, Rib, L2b, R2b) will be received in satellite B and shifted in a manner that maintains the mutual frequency ratio of the signals. The polarization can be reversed between the up and down link. The forward uplink signal comprises different carriers that each pass through one of the satellite transponders (one or more carriers per transponder); wherein each transponder is provided with its own input frequency range (input filter) and with its own output frequency range. This means that there is usually more than one input filter per satellite.
    The signals sent by. the satellite, show a relationship as shown in one of the allocation schemes of Figures 3A to 8. In the event that one of the satellites 30, 40 fails, the forward link signal 28A, 28B to the remaining operational satellite is changed in such a way that it includes signals that take up the frequency portions used by the satellites 30 and 40. When the frequency is shifted (by the known frequency shift as used by the remaining operational satellite) and another transmission takes place by the satellite, the signal will occupy all parts used by the satellites 30 and 40.
    Figure 11 shows a method for using a satellite system implemented by the control unit 24 in the ground station 20 of Figure 9. The method starts in step 100 by causing two satellites (A and B) operate in adjacent parts of the frequency spectrum. In a particular embodiment, the control unit 24 causes the transmit / receive unit 25 to generate a forward link signal 28 for transmission to each satellite 30, 40. The forward link signals are configured in such a way that, after retransmission by the satellites 30 , 40, the transmissions of each satellite will occupy adjacent parts of the frequency spectrum. Step 102 detects an error in one of the satellites. When an error is detected, it will be ensured that the remaining satellite becomes effective over both parts of the frequency spectrum. It is interesting that this does not require a change in the satellites. The forward link signal 28 for the remaining operational satellite is changed in such a way that it takes up parts of the frequency spectrum that were previously used by the two separate satellites. The remaining operational satellite receives the modified forward link signal, shifts its frequency, amplifies it, and retransmits it. In one embodiment, the data rate of the modified forward link signal is changed (e.g., doubled) to thereby maintain the same total data rate as that of the individual signals. Step 106 detects when the satellite that failed has recovered. When the satellite is recovered, the method returns to step 100 and it is ensured that the two satellites operate in adjacent parts of the frequency spectrum. As described above, the method can be applied over a number of bundles of the satellites, with each bundle of satellite A assigned to a first part of the frequency spectrum, and each bundle of satellite B assigned to a second part of the frequency spectrum.
    Figure 12 shows an additional embodiment of the satellite system with two ground stations 20A, 2 OB. In a normal operating mode, the ground station 20A transmits a forward link 28A to satellite 30, and ground station 20B transmits a forward link 28B to satellite 40. In an error mode, it transmits. ground station associated with the remaining satellite, a forward link to the remaining satellite, which will cause the satellite to broadcast over adjacent parts of the frequency spectrum. A communication link 50 between the ground stations 20A, 20B allows sharing of input signals (in error mode) as well as signaling the operating mode.
    The invention is not limited to the embodiments described herein, embodiments that can be modified or modified without departing from the scope of the invention.
    权利要求:
    Claims (18)
    [1]
    A method for using a satellite communication system comprising at least a first ground station and a first satellite and a second satellite that are at least partially responsible for the same coverage area and each satellite is responsible for a particular spot, the method comprising: causing the first satellite to operate in a first part of a frequency spectrum with a first polarization and with a second polarization; ensuring that the second satellite is active in a second part of the frequency spectrum at the first polarization and at the second polarization; wherein each satellite broadcasts with both or with different polarizations in each spot, and, when one of the satellites is unable to operate, it causes the remaining satellite to operate over both the first and the second part of the frequency spectrum.
    [2]
    The method of claim 1, wherein the satellites are multi-bundle satellites, wherein the first satellite is provided with a plurality of first bundles, and the second satellite is provided with a plurality of second bundles, each bundle being responsible for a particular spot, the satellites are responsible for a spot using a first bundle of the first satellite and with a second bundle of the second satellite, the method additionally comprising, for each spot, ensuring that the first satellite uses the first bundle in the first part of the frequency spectrum, and one of the first and second polarizations, causing the second satellite to use the second beam in the second part of the frequency spectrum, thereby using the same polarization as the first bundle.
    [3]
    The method of claim 1, wherein the satellites are multi-bundle satellites, wherein the first satellite is provided with a plurality of first bundles, and the second satellite is provided with a plurality of second bundles, each bundle being responsible for a particular spot, the satellites are responsible for a spot using a first bundle of the first satellite, and using a second bundle of the second satellite, the method additionally comprising, for each spot, the ensuring that the first satellite is the first beam used in the first part of the frequency spectrum, and with both first and second polarizations, causing the second satellite to use the second beam in the second part of the frequency spectrum, thereby making use of both first and second polarizations.
    [4]
    Method according to any one of the preceding claims, wherein the second part of the frequency spectrum is situated next to the first part of the frequency spectrum in terms of frequency.
    [5]
    The method of claim 4, wherein the satellites operate in the first and second portions by operating around a central frequency, and wherein the step is used in which, when one of the satellites is unable to function, it is used for ensured that the remaining satellite is active over both the first and the second part of the frequency spectrum, changing the center frequency around which the remaining satellite is operating.
    [6]
    The method of any one of the preceding claims, further comprising causing the remaining satellite to drive up a symbol rate for a signal sent by the remaining satellite over the first and the second portion of the frequency spectrum.
    [7]
    The method of claim 6, wherein the symbol rate for the signal transmitted by the remaining satellite over the first and the second portion of the frequency spectrum is substantially equal to the combined data rate of signals sent separately by the first satellite and the second satellite.
    [8]
    A method according to any one of the preceding claims, wherein the first part of the frequency spectrum and the second part of the frequency spectrum have the same bandwidth.
    [9]
    A method according to any one of the preceding claims, wherein the first part of the frequency spectrum and the second part of the frequency spectrum have a different bandwidth.
    [10]
    A method according to any one of the preceding claims, wherein there are several first parts of the frequency spectrum and several multiple parts of the frequency spectrum.
    [11]
    The method of claim 10, wherein the plurality of first portions of the frequency spectrum and the plurality of second portions of the frequency spectrum are intertwined.
    [12]
    A method according to any one of the preceding claims, implemented in the first ground station, wherein the first ground station is provided with a first forward communication connection with the first satellite for retransmission by the first satellite, as well as with a second forward communication connection with the second satellite for retransmission by the second satellite, wherein: the step that causes the first satellite to operate in a first portion of the frequency spectrum comprises generating the first forward communication link in such a way that, when a retransmission takes place through the first satellite, a first part of the frequency spectrum is taken with a first polarization and with a second polarization; the step that causes the second satellite to operate in a second part of the frequency spectrum comprises generating the second forward communication link in such a way that, when a retransmission takes place through the second satellite, a second part of the frequency spectrum is taken with a first polarization and with a second polarization; and wherein when one of the satellites is unable to function, the method comprises generating a forward communication link for the remaining satellite, such that when a retransmission takes place through the remaining satellite, both the first satellite part if the second part of the frequency spectrum is taken.
    [13]
    A method according to any of claims 1-11, performed in a first ground station and in a second ground station, wherein the first ground station is provided with a first forward communication connection with the first satellite for retransmission by the first satellite, and the second ground station is provided of a second forward communication link with the second satellite for retransmission by the second satellite, wherein: the step of causing the first satellite to operate in a first portion of the frequency spectrum comprises generating the first forward communication link, namely on in such a way that, when a retransmission takes place through the first satellite, a first portion of the frequency spectrum is occupied with a first polarization and with a second polarization; the step that causes the second satellite to operate in a second part of the frequency spectrum comprises generating the second forward communication link in such a way that, when a retransmission takes place through the second satellite, a second part of the frequency spectrum is taken with a first polarization and with a second polarization; and wherein, if one of the satellites is unable to function, the method comprises generating the forward communication link for the remaining satellite, in such a way that, when there is a retransmission by the remaining satellite, both the first part if the second part of the frequency spectrum is taken.
    [14]
    An apparatus for monitoring the operation of a satellite communication system comprising at least a first satellite and a second satellite which are at least partially responsible for the same coverage area, the apparatus comprising a processing apparatus provided for carrying out the method of any one of the preceding to implement conclusions.
    [15]
    A ground station for use in a satellite communication system comprising at least a first satellite and a second satellite that are at least partially responsible for the same coverage area and each satellite is responsible for a particular spot, comprising: an interface for supporting a first forward communication connection with the first satellite for the retransmission by the first satellite, and for supporting a second forward communication link with the second satellite for the retransmission by the second satellite; a control unit that is provided to: ensure that the first satellite is operative in a first portion of a frequency spectrum, by generating the first forward communication link, in such a way that, when a retransmission takes place by the first satellite, a first part of the frequency spectrum is taken with a first polarization and with a second polarization; ensuring that the second satellite operates in a second part of a frequency spectrum, by generating the second forward communication link, in such a way that, when there is a retransmission by the second satellite, a second part of the frequency spectrum is taken at the first polarization and at the second polarization, ensuring that the first satellite and the second satellite transmit with both or with different polarizations in each spot, and, when one of the satellites is unable to function generating the forward communication link for the remaining satellite in such a way that, when there is retransmission by the remaining satellite, both the first part and the second part of the frequency spectrum are occupied.
    [16]
    16. First ground station for use in a satellite communication system comprising at least a first satellite and a second satellite that are at least partially responsible for the same coverage area and each satellite is responsible for a particular spot, the first ground station comprising: an interface for supporting of a first forward communication link with the first satellite for retransmission by the first satellite; a control unit that is provided to: ensure that the first satellite is operative in a first portion of a frequency spectrum, by generating the first forward communication link, in such a way that, when a retransmission takes place by the first satellite, a first part of the frequency spectrum is taken with a first polarization and with a second polarization; wherein the satellite communication system also comprises a second ground station for supporting a second forward communication link with the second satellite for retransmission by the second satellite which, when retransmission takes place by the second satellite, occupies a second part of the frequency spectrum at the first polarization and with the second polarization; ensuring that the first satellite and the second satellite transmit with both or with different polarizations in each spot, and, when the second satellite is unable to function, generate the forward communication link in such a way that, when retransmission takes place by the first satellite, both the first part and the second part of the frequency spectrum are taken.
    [17]
    A machine-readable medium in which machine-readable instructions are stored which, when executed by a processor, cause the processor to perform the method of any one of claims 1-13.
    [18]
    A satellite communication system, comprising at least one ground station that can be used with a first satellite and with a second satellite that are at least partially responsible for the same coverage area and each satellite is responsible for a particular spot, the system comprising: first means which cause the first satellite to operate in a first part of a frequency spectrum with a first polarization and with a second polarization; second means for causing the second satellite to operate in a second part of the frequency spectrum at the first polarization and at the second polarization, the first satellite and the second satellite transmitting both or different polarizations in each spot, and wherein the first and second means are adapted such that when one of the satellites is unable to function, the remaining satellite is active over both the first part and the second part of the frequency spectrum.
    类似技术:
    公开号 | 公开日 | 专利标题
    EP2789109B1|2016-03-23|Interference management in a hub-spoke spot beam satellite communication system
    US8340015B1|2012-12-25|Incremental gateway deployment in a hub-spoke satellite communication system using static spot beams
    US8509144B2|2013-08-13|Bent pipe beam switching for virtual utility gateways
    DE69839238T2|2009-03-19|A method and arrangement for high data rate transmission in a satellite communications network
    US8897769B2|2014-11-25|Non-interfering utilization of non-geostationary satellite frequency band for geostationary satellite communication
    US8855552B2|2014-10-07|Placement of gateways away from service beams
    US7706787B2|2010-04-27|Multi-beam communication system and method
    US8238816B2|2012-08-07|Satellites and signal distribution methods and off-set pattern for sending signals
    CN108432156B|2021-06-15|Satellite system with increased communication capacity and method for increasing satellite system capacity
    US8538323B2|2013-09-17|Satellite architecture
    US20090298423A1|2009-12-03|Piggy-Back Satellite Payload
    JP2001016154A|2001-01-19|Method and system for performing satellite communication by using on-orbit payload structure and restructure
    BE1020115A5|2013-05-07|SATELLITE COMMUNICATION SYSTEM WITH REDUNDANCE.
    US20200235807A1|2020-07-23|Flexible intra-satellite signal pathways
    CN112290989A|2021-01-29|Satellite-ground communication method and device
    Bousquet et al.2011|Broadband access terabit/s satellite concepts
    Kyrgiazos et al.2012|A feasibility study for a terabit/s satellite for European broadband access
    Betaharon et al.1997|Roles and service utilization of the INTELSAT IX and K-TV satellites
    同族专利:
    公开号 | 公开日
    GB201002864D0|2010-04-07|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US5813634A|1995-10-23|1998-09-29|Motorola, Inc.|Method for replacing failing satellites in a satellite communication system|
    US20040192376A1|2002-03-11|2004-09-30|Grybos David P.|Multi-beam satellite collocation and channel power allocation|
    WO2004010609A1|2002-07-23|2004-01-29|Qualcomm, Incorporated|A satellite communication system with primary and back-up multi-beam satellites|
    WO2009012377A2|2007-07-17|2009-01-22|Viasat, Inc.|Modular satellite transceiver and multi-beam antenna system|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    GB201002864|2010-02-19|
    GB201002864A|GB201002864D0|2010-02-19|2010-02-19|Satellite communication system with redundancy|
    [返回顶部]