초록 ▼

Methods and systems are described for providing end-to-end beamforming. For example, end-to-end beamforming systems include end-to-end relays and ground networks to provide communications to user terminals located in user beam coverage areas. The ground segment can include geographically distributed

Methods and systems are described for providing end-to-end beamforming. For example, end-to-end beamforming systems include end-to-end relays and ground networks to provide communications to user terminals located in user beam coverage areas. The ground segment can include geographically distributed access nodes and a central processing system. Return uplink signals, transmitted from the user terminals, have multipath induced by a plurality of receive/transmit signal paths in the end to end relay and are relayed to the ground network. The ground network, using beamformers, recovers user data streams transmitted by the user terminals from return downlink signals. The ground network, using beamformers generates forward uplink signals from appropriately weighted combinations of user data streams that, after relay by the end-end-end relay, produce forward downlink signals that combine to form user beams.

대표청구항 ▼

1. A system for providing a communication service to user terminals geographically distributed over a user coverage area via an end-to-end relay comprising multiple receive/transmit signal paths, comprising: a beam signal interface that obtains multiple forward beam signals comprising forward user d

1. A system for providing a communication service to user terminals geographically distributed over a user coverage area via an end-to-end relay comprising multiple receive/transmit signal paths, comprising: a beam signal interface that obtains multiple forward beam signals comprising forward user data streams for transmission to a plurality of the user terminals grouped by multiple forward user beam coverage areas;a beam weight generator that generates a forward beam weight matrix for end-to-end beamforming from a plurality of geographically distributed locations to the multiple forward user beam coverage areas via the end-to-end relay, the forward beam weight matrix based at least in part on a first forward uplink channel matrix for forward uplink channels between the plurality of geographically distributed locations and the end-to-end relay over a first frequency range and a second forward uplink channel matrix for the forward uplink channels over a second frequency range, wherein the second frequency range is non-overlapping with the first frequency range;a beamformer coupled with the beam signal interface and the beam weight generator, the beamformer comprising a forward matrix multiplier that obtains a plurality of access-node specific forward signals based on a matrix product of the forward beam weight matrix and a vector of the forward beam signals; andan access node cluster comprising a plurality of access nodes at the plurality of geographically distributed locations, wherein each of the plurality of access nodes obtains a respective first one of the plurality of access-node specific forward signals and transmits a first forward uplink signal over the first frequency range to the end-to-end relay based on the respective first one of the plurality of access node-specific forward signals, and obtains a respective second one of the plurality of access-node specific forward signals and transmits a second forward uplink signal over the second frequency range to the end-to-end relay based on the respective second one of the second plurality of access node-specific forward signals, and wherein, for the plurality of access nodes, the respective first and second forward uplink signals are pre-corrected to compensate for respective path delays and phase shifts introduced between the plurality of access nodes and the end-to-end relay. 2. The system of claim 1, wherein each of the first forward uplink signals transmitted from the plurality of access nodes is carried via at least a subset of a first set of the multiple receive/transmit signal paths of the end-to-end relay and each of the second forward uplink signals transmitted from the plurality of access nodes is carried via at least a subset of a second set of the multiple receive/transmit signal paths of the end-to-end relay. 3. The system of claim 1, wherein at least a subset of the first set of forward uplink signals and at least a subset of the second set of forward uplink signals contribute to forming at least one forward user beam associated with at least one of the multiple forward user beam coverage areas. 4. The system of claim 2, wherein the first set of the multiple receive/transmit signal paths are coupled with a first plurality of antenna elements of a user-link antenna subsystem of the end-to-end relay and the second set of the multiple receive/transmit signal paths are coupled with a second plurality of antenna elements of the user-link antenna subsystem. 5. The system of claim 4, wherein the first plurality of antenna elements is a first subset of antenna elements of an array of cooperating user-link constituent antenna elements, and the second plurality of antenna elements is a second subset of antenna elements of the array of cooperating user-link constituent antenna elements. 6. The system of claim 4, wherein the first plurality of antenna elements is a first array of cooperating user-link constituent antenna elements, and the second plurality of antenna elements is a second array of cooperating user-link constituent antenna elements. 7. The system of claim 4, wherein a number of elements in the first plurality of antenna elements is different from a number of elements in the second plurality of antenna elements. 8. The system of claim 1, wherein a bandwidth of the first frequency range is different from a bandwidth of the second frequency range. 9. The system of claim 1, wherein the end-to-end relay relays the first set of forward uplink signals and the second set of forward uplink signals over a third frequency range. 10. The system of claim 9, wherein a bandwidth of the third frequency range is greater than a bandwidth of at least one of the first frequency range or the second frequency range. 11. The system of claim 9, wherein a bandwidth of the third frequency range is less than a combined bandwidth of the first and second frequency ranges. 12. The system of claim 9, wherein a bandwidth of the third frequency range is the same as a bandwidth of at least one of the first frequency range or the second frequency range. 13. A method for providing a communication service to user terminals geographically distributed over a user coverage area via an end-to-end relay comprising multiple receive/transmit signal paths, comprising: obtaining multiple forward beam signals comprising forward user data streams for transmission to a plurality of the user terminals grouped by multiple forward user beam coverage areas;identifying a forward beam weight matrix for end-to-end beamforming from a plurality of access nodes of an access node cluster to the multiple forward user beam coverage areas via the end-to-end relay, the forward beam weight matrix based at least in part on a first forward uplink channel matrix for forward uplink channels between the plurality of access nodes and the end-to-end relay over a first frequency range and a second forward uplink channel matrix for the forward uplink channels over a second frequency range, wherein the second frequency range is non-overlapping with the first frequency range;generating a plurality of access-node specific forward signals for transmission by the plurality of access nodes, each of the access node-specific forward signals comprising a composite of respective forward beam signals weighted by respective forward beamforming weights of the forward beam weight matrix; andtransmitting, by the plurality of access nodes to the end-to-end relay, a first forward uplink signal over the first frequency range and a second forward uplink signal over the second frequency range, the first forward uplink signal based on a respective first one of the plurality of access node-specific forward signals and the second forward uplink signal based on a respective second one of the second plurality of access node-specific forward signals, wherein the respective first and second forward uplink signals are pre-corrected to compensate for respective path delays and phase shifts introduced between the plurality of access nodes and the end-to-end relay. 14. The method of claim 13, wherein each of the first forward uplink signals transmitted from the plurality of access nodes is carried via at least a subset of a first set of the multiple receive/transmit signal paths of the end-to-end relay and each of the second forward uplink signals transmitted from the plurality of access nodes is carried via at least a subset of a second set of the multiple receive/transmit signal paths of the end-to-end relay. 15. The method of claim 13, wherein at least a subset of the first set of forward uplink signals and at least a subset of the second set of forward uplink signals contribute to forming at least one forward user beam associated with at least one of the multiple forward user beam coverage areas. 16. The method of claim 13, wherein a bandwidth of the first frequency range is different from a bandwidth of the second frequency range. 17. The method of claim 13, further comprising: relaying, by the end-to-end relay, the first set of forward uplink signals and the second set of forward uplink signals over a third frequency range. 18. The method of claim 17, wherein a bandwidth of the third frequency range is greater than a bandwidth of at least one of the first frequency range or the second frequency range. 19. The method of claim 17, wherein a bandwidth of the third frequency range is less than a combined bandwidth of the first and second frequency ranges. 20. The method of claim 17, wherein a bandwidth of the third frequency range is the same as a bandwidth of at least one of the first frequency range or the second frequency range. 21. A system for providing a communication service to user terminals geographically distributed over a user coverage area via an end-to-end relay comprising multiple receive/transmit signal paths, comprising: an access node cluster comprising a plurality of access nodes at a plurality of geographically distributed locations, each of the plurality of access nodes comprising a receiver that receives a first return downlink signal from the end-to-end relay over a first frequency range, the first return downlink signal comprising a composite of return uplink signals transmitted from a plurality of the user terminals and relayed by at least a subset of a first set of the multiple receive/transmit signal paths of the end-to-end relay to form a first composite return signal and that receives a second return downlink signal from the end-to-end relay over a second frequency range, the second return downlink signal comprising a composite of the return uplink signals transmitted from the plurality of the user terminals and relayed by at least a subset of a second set of the multiple receive/transmit signal paths of the end-to-end relay to form a second composite return signal, and wherein the second frequency range is non-overlapping with the first frequency range;a beam weight generator that generates a return beam weight matrix for end-to-end beamforming of transmissions from multiple return user beam coverage areas to the plurality of geographically distributed locations via the end-to-end relay, the return beam weight matrix based at least in part on a first return downlink channel matrix for return downlink channels between the end-to-end relay and the plurality of geographically distributed locations over the first frequency range and a second return downlink channel matrix for the return downlink channels over the second frequency range; anda return beamformer coupled with the beam weight generator, the return beamformer comprising a matrix multiplier that obtains respective return beam signals for the multiple return user beam coverage areas based on a matrix product of the return beam weight matrix and a vector of the first and second composite return signals, wherein the first and second composite return signals are corrected for timing and phase for respective path delays and phase shifts between the end-to-end relay and the plurality of access nodes. 22. The system of claim 21, wherein a bandwidth of the first frequency range is different from a bandwidth of the second frequency range. 23. The system of claim 21, wherein the first frequency range begins at a first base frequency and the second frequency range begins at a second base frequency that is at least one and a half times the first base frequency. 24. The system of claim 21, wherein at least one of the return beam signals for at least one of the return user beam coverage areas is determined based on at least a subset of the first return downlink signals and at least a subset of the second return downlink signals. 25. The system of claim 21, wherein: the first set of the multiple receive/transmit signal paths are coupled with a first plurality of antenna elements of a user-link antenna subsystem of the end-to-end relay and the second set of the multiple receive/transmit signal paths are coupled with a second plurality of antenna elements of the user-link antenna subsystem; andthe first plurality of antenna elements is a first subset of antenna elements of an array of cooperating user-link constituent antenna elements, and the second plurality of antenna elements is a second subset of antenna elements of the array of cooperating user-link constituent antenna elements. 26. The system of claim 21, wherein: the first set of the multiple receive/transmit signal paths are coupled with a first plurality of antenna elements of a user-link antenna subsystem of the end-to-end relay and the second set of the multiple receive/transmit signal paths are coupled with a second plurality of antenna elements of the user-link antenna subsystem; andthe first plurality of antenna elements is a first array of cooperating user-link constituent antenna elements, and the second plurality of antenna elements is a second array of cooperating user-link constituent antenna elements. 27. A method for providing a communication service to user terminals geographically distributed over a user coverage area via an end-to-end relay comprising multiple receive/transmit signal paths, comprising: receiving, from the end-to-end relay at an access node cluster comprising a plurality of access nodes at a plurality of geographically distributed locations, a first return downlink signal over a first frequency range and a second return downlink signal over a second frequency range, the first return downlink signal comprising a composite of return uplink signals transmitted from a plurality of the user terminals and relayed by at least a subset of a first set of the multiple receive/transmit signal paths of the end-to-end relay to form a first composite return signal and the second return downlink signal comprising a composite of the return uplink signals transmitted from the plurality of the user terminals and relayed by at least a subset of a second set of the multiple receive/transmit signal paths of the end-to-end relay to form a second composite return signal, and wherein the second frequency range is non-overlapping with the first frequency range;generating a return beam weight matrix for end-to-end beamforming of transmissions from multiple return user beam coverage areas to the plurality of geographically distributed locations via the end-to-end relay, the return beam weight matrix based at least in part on a first return downlink channel matrix for return downlink channels between the end-to-end relay and the plurality of geographically distributed locations over the first frequency range and a second return downlink channel matrix for the return downlink channels over the second frequency range;applying, to a vector of the first and second composite return signals, respective beamforming weights of the return beam weight matrix to obtain a respective plurality of weighted composite return signals associated with each of the multiple return user beam coverage areas; andcombining, for the each of the multiple return user beam coverage areas, the respective plurality of weighted composite return signals to obtain a return beam signal associated with the each of the multiple return user beam coverage areas, wherein the respective plurality of weighted composite return signals are corrected to compensate for respective path delays and phase shifts between the end-to-end relay and the plurality of access nodes prior to the combining. 28. The method of claim 27, wherein a bandwidth of the first frequency range is different from a bandwidth of the second frequency range. 29. The method of claim 27, wherein the first frequency range begins at a first base frequency and the second frequency range begins at a second base frequency that is at least one and a half times the first base frequency. 30. The method of claim 27, wherein at least one of the return beam signals for at least one of the return user beam coverage areas is determined based on at least a subset of the first return downlink signals and at least a subset of the second return downlink signals.