Systems and methods for satellite forward link transmit diversity using orthagonal space coding
First Claim
1. A method of transmitting communications signals from a satellite to a wireless terminal, comprising:
- determining a location of the wireless terminal;
selecting a plurality of antenna feed elements at the satellite in response to the determined location of the wireless terminal;
block coding a plurality of symbols into a number of transmit streams equal to the number of selected antenna feed elements wherein block coding the plurality of symbols comprises space-code encoding the plurality of symbols; and
transmitting the transmit streams over the selected plurality of antenna feed elements;
generating a plurality of extended pseudonoise codes wL based on a pseudonoise code w associated with the wireless terminal, wherein the extended pseudonoise codes wL have a length that is m-times longer than the pseudonoise code w;
repeating the symbols m times; and
constructing a transmission matrix using the repeated symbols;
wherein block coding the transmit streams comprises combining the extended pseudonoise codes with the transmission matrix; and
wherein the transmission matrix has a form such that the product of the transmission matrix and its transpose conjugate is equal to the sum of the squares of the plurality of symbols used to generate the transmission matrix multiplied by a diagonal unity matrix.
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Accused Products
Abstract
Methods of transmitting communications signals from a satellite to a wireless terminal include determining a location of the wireless terminal, selecting a plurality of antenna feed elements at the satellite in response to the determined location of the wireless terminal, block coding a plurality of symbols into a number of transmit streams equal to the number of selected antenna feed elements, and transmitting the transmit streams over the selected plurality of antenna feed elements. Block coding the plurality of symbols may include space-code, space-time and/or space-frequency encoding the plurality of symbols. Related satellites, satellite gateways and satellite communications systems are also disclosed.
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Citations
64 Claims
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1. A method of transmitting communications signals from a satellite to a wireless terminal, comprising:
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determining a location of the wireless terminal; selecting a plurality of antenna feed elements at the satellite in response to the determined location of the wireless terminal; block coding a plurality of symbols into a number of transmit streams equal to the number of selected antenna feed elements wherein block coding the plurality of symbols comprises space-code encoding the plurality of symbols; and transmitting the transmit streams over the selected plurality of antenna feed elements; generating a plurality of extended pseudonoise codes wL based on a pseudonoise code w associated with the wireless terminal, wherein the extended pseudonoise codes wL have a length that is m-times longer than the pseudonoise code w; repeating the symbols m times; and constructing a transmission matrix using the repeated symbols; wherein block coding the transmit streams comprises combining the extended pseudonoise codes with the transmission matrix; and wherein the transmission matrix has a form such that the product of the transmission matrix and its transpose conjugate is equal to the sum of the squares of the plurality of symbols used to generate the transmission matrix multiplied by a diagonal unity matrix. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A satellite configured to transmit communications signals to a wireless terminal, comprising:
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an antenna including a plurality of feed elements; a controller configured to obtain a location of the wireless terminal and configured to select a plurality of the antenna feed elements in response to the obtained location of the wireless terminal, and configured to block code a plurality of symbols into a number of transmit streams equal to the number of selected antenna feed elements wherein the controller is configured to block code the plurality of symbols by space-time encoding the plurality of symbols; a transmitter configured to transmit the transmit streams over the selected plurality of antenna feed elements; and a time scheduler; wherein the controller is configured to generate a transmission matrix using the plurality and wherein the transmitter is configured to transmit the transmit streams over the selected plurality of antenna feed elements at time intervals specified by the time scheduler; and wherein the number of selected antenna feed elements is four, and wherein the transmission matrix has the form; - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33)
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34. A satellite gateway configured to transmit communications signals to a wireless terminal via a satellite including an antenna having a plurality of feed elements, comprising:
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a controller configured to obtain a location of the wireless terminal and configured to select a plurality of the antenna feed elements in response to the obtained location of the wireless terminal and configured to block code a plurality of symbols into a number of transmit streams equal to the number of selected antenna feed elements wherein the controller is configured to block code the plurality of symbols by space-time encoding the plurality of symbols; a transmitter configured to transmit the transmit streams to the satellite for transmission over the selected plurality of antenna feed elements; and a time scheduler; wherein the controller is configured to generate a transmission matrix using the plurality of symbols, and wherein the transmitter is configured to transmit the transmit streams over the selected plurality of antenna feed elements at time intervals specified by the time scheduler; and wherein the number of selected antenna feed elements is four, and wherein the transmission matrix has the form; - View Dependent Claims (35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49)
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50. A satellite communications system, comprising:
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a satellite including an antenna having a plurality of antenna feed elements; and a satellite gateway comprising; a controller configured to obtain a location of a wireless terminal within a geographic footprint of the satellite, and configured to select a plurality of the antenna feed elements in response to the obtained location of the wireless terminal and configured to block code a plurality of symbols into a number of transmit streams equal to the number of selected antenna feed elements wherein the controller is configured to block code the plurality of symbols by space-time encoding the plurality of symbols; and a transmitter configured to transmit the transmit streams to the satellite for transmission over the selected plurality of antenna feed elements; and a time scheduler; wherein the controller is configured to generate a transmission matrix using the plurality of symbols, and wherein the transmitter is configured to transmit the transmit streams over the selected plurality of antenna feed elements at time intervals specified by the time scheduler; and wherein the number of selected antenna feed elements is four, and wherein the transmission matrix has the form; - View Dependent Claims (51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64)
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Specification