Ground network with access node clusters for end-to-end beamforming

Patent metadata

Field	Value
Publication number	US-10142011-B2
Application number	US-201715719209-A
Country	US
Kind code	B2
Filing date	Sep 28, 2017
Priority date	Apr 10, 2015
Publication date	Nov 27, 2018
Grant date	Nov 27, 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 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 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 to the multiple forward user beam coverage areas via the end-to-end relay;
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; and
a plurality of access node clusters, wherein each access node cluster is associated with a corresponding one of a plurality of access node areas, and wherein each of the plurality of access node clusters comprises:
a plurality of access nodes geographically distributed within the corresponding access node area, wherein each access node cluster obtains a respective set of the plurality of access node-specific forward signals, and wherein each of the plurality of access nodes of the each access node cluster comprises a transmitter that transmits a respective forward uplink signal to the end-to-end relay based on one of the respective set of the plurality of access node-specific forward signals, 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.

2. The system of claim 1 , wherein each of the plurality of access node areas is non-overlapping with other access node areas of the plurality of access node areas.

3. The system of claim 1 , wherein at least one of the plurality of access node areas is non-overlapping with the user coverage area.

4. The system of claim 1 , wherein a first set of forward uplink signals from a first access node cluster of the plurality of access node clusters are carried via a first set of the multiple receive/transmit signal paths and a second set of forward uplink signals from a second access node cluster of the plurality of access node clusters are carried via a second set of the multiple receive/transmit signal paths.

5. The system of claim 4 , wherein the first set of forward uplink signals and the second set of forward uplink signals both contribute to forming at least one forward user beam associated with at least one of the multiple forward user beam coverage areas.

6. The system of claim 4 , wherein:
the first set of the multiple receive/transmit signal paths are coupled with a first array of cooperating user-link constituent 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 array of cooperating user-link constituent antenna elements of the user-link antenna subsystem;
the user coverage area comprises a first user coverage area and a second coverage area;
the first array of cooperating user-link constituent antenna elements is associated with the first user coverage area; and
the second array of cooperating user-link constituent antenna elements is associated with the second user coverage area.

7. The system of claim 1 , wherein the multiple receive/transmit signal paths are selectively coupled via a first set of switches to one of a first array of cooperating feeder-link constituent antenna elements associated with a first access node cluster of the plurality of access node clusters or a second array of cooperating feeder-link constituent antenna elements associated with a second access node cluster of the plurality of access node clusters.

8. The system of claim 7 , wherein the user coverage area comprises a first user coverage area and a second user coverage area, and wherein the multiple receive/transmit signal paths are selectively coupled via a second set of switches to one of a first array of cooperating user-link constituent antenna elements associated with the first user coverage area or a second array of cooperating user-link constituent antenna elements associated with the second user coverage area.

9. The system of claim 8 , wherein the first user coverage area is non-overlapping with the corresponding access node area of the first access node cluster and the second user coverage area is non-overlapping with the corresponding access node area of the second access node cluster.

10. The system of claim 1 , wherein:
each of the plurality of access nodes comprises a receiver that receives a respective return downlink signal from the end-to-end relay via an antenna, each of the respective return downlink signals comprising a composite of return uplink signals transmitted from a plurality of the user terminals and relayed by at least a subset of the multiple receive/transmit signal paths of the end-to-end relay to form a composite return signal;
the beam weight generator generates a return beam weight matrix for end-to-end beamforming of transmissions from multiple return user beam coverage areas to the plurality of access node clusters via the end-to-end relay; and
the beamformer comprises a return 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 respective composite return signals, wherein the respective 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.

11. 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 of transmissions from a set of access nodes to the multiple forward user beam coverage areas via the end-to-end relay, the set of access nodes comprising access nodes of at least one of a plurality of access node clusters, wherein each of the plurality of access node clusters comprises a plurality of access nodes at geographically distributed locations within a corresponding one of a plurality of access node areas;
generating respective access node-specific forward signals for transmission by the set of access nodes, each of the respective 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; and
transmitting respective forward uplink signals from the set of access nodes based on the respective access node-specific forward signals, wherein the respective forward uplink signals are pre-corrected to compensate for respective path delays and phase shifts between the plurality of access nodes and the end-to-end relay.

12. The method of claim 11 , wherein the transmitting comprises:
transmitting a first set of forward uplink signals from a first access node cluster of the plurality of access node clusters to the end-to-end relay to be carried via a first set of the multiple receive/transmit signal paths; and
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Assignees

• Viasat Inc

Inventors

• Buer Kenneth V
• Miller Mark J
• Cronin Christopher J
• Dankberg Mark D
• Runyon Donald L

Classifications

• H04W4/00

  Services specially adapted for wireless communication networks; Facilities therefor · 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

• H04B7/0413

  MIMO systems · CPC title

• H01Q1/288

  Satellite antennas · CPC title

• H04W16/26

  Cell enhancers {or enhancement}, e.g. for tunnels, building shadow · CPC title