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US 10,312,984 B2Granted
Distributed airborne beamforming system
AssigneeMassachusetts Institute of Technology
InventorsNavid Yazdani, David W. Browne, Keith William Forsythe
Life of this patent
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Abstract
A distributed beamforming communication system including independent aerial nodes forming an antenna array is described. Described herein is a distributed beamforming array which utilizes independent aerial relay nodes or platforms (i.e. no strict control of relay node position, no communication between the relay nodes, and no coordinated transmission among the relay nodes) to form a distributed beamforming antenna.
Claims20
A system comprising:
- two or more aerial relay nodes, at least one of which can move independently of at least one of the other two or more aerial relay nodes;
- a receiver to receive a transmission from each of the two or more aerial relay nodes and convert the transmission to a digital representation of each transmission at an output thereof, wherein the transmission comprises at least a data message and a reference signature for calculation of desired beamforming weights;
- and
- an adaptive beamforming processor, coupled to the output of said receiver, said adaptive beamforming processor configured to:
- receive the digital representation of each transmission from each of the two or more aerial relay nodes including the reference signature for calculation of the desired beamforming weights from each of the two or more aerial relay nodes;
- generate a set of beamforming weights from signals received from two or more aerial relay nodes where said weights are based on parameters of the reference signature received from each respective aerial relay node wherein the reference signature parameters relate to:
- physical spacing between at least some of the two or more aerial relay nodes;
- relative motion between at least some of the two or more aerial relay nodes;
- and signal timing between at least some of the two or more aerial relay nodes and wherein the set of weights compensates for at least physical spacing, relative motion, and signal timing;
- apply the weights to the respective transmission received from the respective relay node to form a reconstructed signal forming an effective desired beampattern;
- and
- process the reconstructed signal through a desired beamformer.
9 more elements
A beamforming system for forming a beampattern based upon signals received from a plurality of aerial relay nodes, at least one of which can move independently of at least one of the other two or more aerial relay nodes, the beamforming system comprising:
- receiving means for receiving a plurality of aerial relay node transmissions from at least two of the plurality aerial relay nodes, wherein each aerial relay node transmission having a transmit frequency which is unique with respect to a transmit frequency of other one of the plurality of aerial relay nodes and which includes at least a data portion and a reference signature;
- digitizing means, coupled to said receiving means, said digitizing means for receiving the plurality of aerial relay node transmissions provided thereto from said receiving means and for digitizing the plurality of aerial relay node transmissions;
- an adaptive beamforming processor having an input and an output with the input coupled to receive digitized aerial relay node transmissions from an output of said digitizing means, said adaptive beamforming processor for:
- generating a set of weighting signals for each of the aerial relay node transmissions wherein the set of weighting signals are selected to allow said adaptive beamforming processor to detect the reference signature of the aerial relay node transmission received from each respective aerial relay node, wherein parameters of the reference signature relate to physical spacing between at least some of the plurality of aerial relay nodes, relative motion between at least some of the plurality of aerial relay nodes, and signal timing between at least some of the plurality of aerial relay nodes and wherein the set of weighting signals compensates for at least physical spacing, relative motion, and signal timing;
- and
- providing the set of weighting signals at the output thereof;
- a weighting means, having a first input coupled to receive weighting signals from said adaptive beamforming processor, a second input coupled to the output of said digitizing means and having an output, said weighting means for applying a set of weighting signals provided thereto from said adaptive beamforming processor to respective ones of the digitized aerial relay node transmissions to form a weighted set of digitized aerial relay node transmissions at an output thereof;
- and
- a summing means, coupled to said digitizing means, said summing means for summing the weighted digitized aerial relay node transmissions to form a beam at an output of the beamforming system.
6 more elements
An adaptive beamforming processor for receiving a plurality of digitized aerial relay node transmissions, each of the plurality of digitized aerial relay node transmissions provided from a corresponding one of a plurality of independent aerial relay nodes, the adaptive beamforming processor comprising:
- a weighting processor for generating a set of weighting signals for each of the aerial relay node transmissions wherein the set of weighting signals are selected such that the adaptive beamforming processor is configured to:
- identify a reference signal portion of the aerial relay node transmission received from each respective aerial relay node;
- and
- compute a steering vector comprising the weighting signals based upon parameters of the reference signal portion, wherein the parameters of the reference signal portion relate to physical spacing between at least some of the plurality of independent aerial relay nodes, relative motion between at least some of the plurality of independent aerial relay nodes, and signal timing between at least some of the plurality of independent aerial relay nodes;
- compute a covariance matrix representing a correlation between each aerial relay node that produced the aerial relay node transmissions;
- compute a weight vector to be applied to the aerial relay node transmissions, wherein the weight vector compensates for at least physical spacing, relative motion, and signal timing;
- and
- apply the weight vector to the aerial relay node transmissions to generate a set of corrected aerial relay node transmissions.
5 more elements
Dependencies are inferred from the claim text.