System and method for reducing VSAT apertures via satellite MIMO
First Claim
1. A system for communicating with a remote ground terminal via a first satellite and a second satellite adjacent the fist satellite, the system comprising:
- a first hub antenna configured to receive a first return signal from and to transmit a first forward signal to the first satellite;
a second hub antenna configured to receive a second return signal from and to transmit a second forward signal to the second satellite; and
a hub station configured to determine time delay and frequency shift between the first return signal and the second return signal after, and to apply the determined time delay and frequency shift to at least one of the first forward signal and the second forward signal so the first forward signal and the second forward signal are time- and frequency-aligned when received at the remote ground terminal via the first satellite and the second satellite,wherein the first return signal and the second return signal are transmitted from the remote ground terminal to the first hub antenna and the second hub antenna via the first satellite and the second satellite.
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Accused Products
Abstract
A system and method of reducing VSAT apertures via satellite MIMO is disclosed. The system and method comprise a first hub antenna configured to receive a first return signal from and to transmit a first forward signal to a first adjacent satellite, a second hub antenna configured to receive a second return signal from and to transmit a second forward signal to a second adjacent satellite, and a hub station configured to determine time delay and frequency shift between the first return signal and the second return signal after they are received by the first hub antenna and the second hub antenna, and to apply the determined time delay and frequency shift to one of the first forward signal and the second forward signal prior to transmitting them so the first forward signal and the second forward signal are time- and frequency-aligned when received at the remote ground terminal via the first adjacent satellite and the second adjacent satellite, wherein the first return signal and the second return signal are transmitted from the remote ground terminal to the first hub antenna and the second hub antenna via the first adjacent satellite and the second adjacent satellite. Similar time- and frequency-aligning can be achieved at the remote ground terminal using polarized signals transmitted from the remote ground terminal.
42 Citations
34 Claims
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1. A system for communicating with a remote ground terminal via a first satellite and a second satellite adjacent the fist satellite, the system comprising:
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a first hub antenna configured to receive a first return signal from and to transmit a first forward signal to the first satellite; a second hub antenna configured to receive a second return signal from and to transmit a second forward signal to the second satellite; and a hub station configured to determine time delay and frequency shift between the first return signal and the second return signal after, and to apply the determined time delay and frequency shift to at least one of the first forward signal and the second forward signal so the first forward signal and the second forward signal are time- and frequency-aligned when received at the remote ground terminal via the first satellite and the second satellite, wherein the first return signal and the second return signal are transmitted from the remote ground terminal to the first hub antenna and the second hub antenna via the first satellite and the second satellite. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for communicating with a remote ground terminal via a first satellite and a second satellite adjacent to the first satellite, the method comprising the steps of:
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transmitting a return signal from the remote ground terminal to the first satellite and the second satellite; re-transmitting the return signal from the first satellite as a first return signal; re-transmitting the return signal from the second satellite as a second return signal; receiving the fist return signal with a first hub antenna; receiving the second return signal with a second hub antenna; determining time delay and frequency shift between the first return signal and the second return signal after they are received with the first hub antenna and the second hub antenna; and applying the determined time delay and frequency shift to at least one of a first forward signal and a second forward signal prior to transmitting the first forward signal with the first hub antenna and transmitting the second forward signal with the second hub antenna so the first forward signal and the second forward signal are time- and frequency-aligned when received at the remote ground terminal via the first satellite and the second satellite. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A system for communicating with a remote ground terminal via adjacent satellites comprising:
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a remote ground terminal configured to send two or more first polarized signals to the adjacent satellites and to receive the two or more first polarized signals from the adjacent satellites when the adjacent satellites re-transmit the two or more first polarized signals, wherein the remote ground terminal receives the re-transmitted two or more first polarized signals, determines differential delay and frequency shift between the re-transmitted two or more first polarized signals, and applies the determined differential delay and frequency shift to two or more subsequently received second polarized signals so the two or more subsequently received second polarized signals are time- and -frequency aligned for processing at the remote ground terminal. - View Dependent Claims (18, 19, 20, 21, 22, 23)
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24. A method for enabling reduced antenna aperture in a remote ground terminal, comprising the steps of:
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sending two or more polarized signals from the remote ground terminal to two or more adjacent satellites; receiving the two or more polarized first signals at the remote ground terminal when they are repeated for transmission by the two or more adjacent satellites; determining differential delay and frequency shift between the repeated two or more polarized signals received at the remote ground terminal; applying the determined differential delay and frequency shift to subsequently received signals from the two or more adjacent satellites to time- and frequency-align the subsequently received signals for processing at the remote ground terminal. - View Dependent Claims (25, 26, 27, 28, 29, 30)
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31. A for communicating with a remote ground terminal via adjacent satellites comprising the steps of:
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sending a first polarized signal and a second polarized signal to the remote ground terminal from a first hub antenna and a second hub antenna via a first satellite and a second satellite adjacent to the first satellite, the first and second polarized signals each having a dominant component and an interference component; auto-correlating the first and second polarized signals at the remote ground terminal to identify the dominant component in each of the first and second polarized signals; determining the values for frequency shift and time delay between the dominant components of the first and second polarized signals; time- and frequency-aligning the dominant component of the first polarized signal with the interference component of the second polarized signal and the dominant component of the second polarized signal with the interference component of the first polarized signal using the determined values for frequency shift and time delay; cancelling the interference component of the second polarized signal from the time- and frequency-aligned dominant component of the first polarized signal; cancelling the interference component of the first polarized signal from the time- and frequency-aligned dominant component of the second polarized signal; and combining the dominant component of the first polarized signal with the dominant component of the second polarized signals after cancelling the interference components, wherein the interference components of the first and second polarized signals are cancelled and the dominant components of the first and second polarized signals are combined using a plurality of interference cancellers that operate iteratively with one another. - View Dependent Claims (32, 33, 34)
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Specification