Access node farm for end-to-end beamforming

Patent metadata

Field	Value
Publication number	US-10084532-B2
Application number	US-201715719249-A
Country	US
Kind code	B2
Filing date	Sep 28, 2017
Priority date	Apr 10, 2015
Publication date	Sep 25, 2018
Grant date	Sep 25, 2018

Abstract

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.

First claim

What is claimed is:

1. A system for providing a communication service to user terminals geographically distributed over a user coverage area comprising multiple forward user beam coverage areas via an end-to-end relay comprising multiple forward receive/transmit signal paths, comprising:
a plurality of access nodes geographically distributed within an access node area having a physical area that is smaller than a physical area of the user coverage area, the plurality of access nodes transmitting respective access node-specific forward signals to the end-to-end relay, each of the respective access node-specific forward signals comprising a composite of respective forward beam signals weighted by respective forward beamforming weights of a forward beam weight matrix for end-to-end beamforming of transmissions from the plurality of access nodes to the multiple forward user beam coverage areas via the end-to-end relay, each access node of the plurality of access nodes comprising:
a network interface that obtains one of the respective access node-specific forward signals;
a transmitter that transmits a forward uplink signal comprising the one of the respective access node-specific forward signals to the end-to-end relay;
a controller that pre-corrects the forward uplink signal to compensate for a path delay and a phase shift introduced between the access node and the end-to-end relay;
a receiver that receives a return downlink signal from the end-to-end relay, the return downlink signal comprising a relay beacon signal and return uplink signals from a plurality of the user terminals relayed by the end-to-end relay, to form a composite return signal;
a relay beacon signal demodulator that demodulates the relay beacon signal to obtain relay timing information; and
a multiplexer that multiplexes the composite return signal with the relay timing information to obtain a multiplexed composite return signal,

wherein the network interface sends the multiplexed composite return signal to a return beamformer.

2. The system of claim 1 , wherein the access node area at least partially overlaps with a low demand area of the user coverage area.

3. The system of claim 2 , wherein the low demand area of the user coverage area comprises an area in which the demand for the communication service is below a demand threshold.

4. The system of claim 1 , further comprising a distribution network that distributes the plurality of access node-specific forward signals.

5. The system of claim 1 , wherein the access node area is contained within the user coverage area.

6. The system of claim 1 , wherein the physical area of the access node area is less than one half of the physical area of the user coverage area.

7. The system of claim 1 , wherein the physical area of the access node area is less than one-fifth of the physical area of the user coverage area.

8. The system of claim 1 , wherein the physical area of the access node area is less than one-tenth of the physical area of the user coverage area.

9. The system of claim 1 , wherein the access node area is a single contiguous coverage area.

10. 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 forward receive/transmit signal paths, comprising:
a forward beamformer that obtains multiple forward beam signals comprising forward user data streams for transmission to the user terminals grouped by multiple forward user beam coverage areas and generates a plurality of access-node specific forward signals based on a matrix product of a forward beam weight matrix for end-to-end beamforming of transmissions from an access node area that is at least partially overlapping with an aquatic body to the multiple forward user beam coverage areas via the end-to-end relay and a vector of the forward beam signals;
a plurality of access nodes geographically distributed within the access node area, wherein each of the plurality of access nodes obtains a respective one of the plurality of access node-specific forward signals, and wherein each of the plurality of access nodes comprises a transmitter that transmits a respective forward uplink signal to the end-to-end relay based on the respective access node-specific forward signal, and wherein the respective 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, and wherein at least one of the plurality of access nodes is located within the aquatic body; and
a beam weight generator that generates the forward beam weight matrix as a first forward beam weight matrix for end-to-end beamforming of transmissions from the plurality of access nodes disposed at first locations within the access node area, and generates the forward beam weight matrix as a second forward beam weight matrix for end-to-end beamforming of transmissions from the plurality of access nodes disposed at second locations within the access node area in response to a change in location of at least one of the plurality of access nodes.

11. The system of claim 10 , wherein the at least one of the plurality of access nodes is located on a floating platform in the aquatic body.

12. The system of claim 10 , further comprising a distribution network that distributes the plurality of access node-specific forward signals.

13. The system of claim 12 , wherein the distribution network comprises a submarine cable coupled with the forward beamformer and the at least one of the plurality of access nodes.

14. The system of claim 12 , wherein the distribution network comprises a free space optical link that couples the forward beamformer and the at least one of the plurality of access nodes.

15. The system of claim 12 , wherein the forward beamformer or the distribution network are located within the aquatic body.

16. The system of claim 10 , wherein the aquatic body comprises an ocean.

17. The system of claim 10 , wherein the user coverage area comprises a terrestrial land mass.

18. The system of claim 10 , wherein the access node area is at least partially overlapping with the user coverage area.

19. A system for providing a communication service to user terminals geographically distributed over a user coverage area comprising multiple forward user beam coverage areas via an end-to-end relay comprising multiple forward receive/transmit signal paths, comprising:
a plurality of access nodes disposed on respective mobile platforms within a first access node area having a physical area that is smaller than a physical area of the user coverage area, the plurality of access nodes transmitting respective access node-specific forward signals to the end-to-end relay, each of the respective access node-specific forward signals comprising a composite of respective forward beam signals weighted by respective forward beamforming weights of a first forward beam weight matrix for end-to-end beamforming of transmissions from the plurality of access nodes disposed at first locations within the first access node area to the multiple forward user beam coverage areas via the end-to-end relay, each access node of the plurality of access nodes comprising:
a network interface that obtains one of the respective access node-specific forward signals;
a transmitter that transmits a forward uplink signal comprising the one of the respective access node-specific forward signals to the end-to-end relay; and
a controller that pre-corrects t

Assignees

• Viasat Inc

Inventors

• Buer Kenneth V
• Miller Mark J
• Cronin Christopher J

Classifications

• H04W4/00

  Services specially adapted for wireless communication networks; Facilities therefor · CPC title

• H04B7/0413

  MIMO systems · CPC title

• H04B7/024

  Co-operative use of antennas of several sites, e.g. in co-ordinated multipoint or co-operative multiple-input multiple-output [MIMO] systems · CPC title

• H04B10/118

  specially adapted for satellite communication · CPC title

• H04B7/0617

  for beam forming · CPC title