Synchronization of distributed nodes in wireless systems
First Claim
1. A method of communicating between an array of ad hoc nodes and a target, the array comprising a master node and a plurality of slave nodes, the method comprising steps of:
- communicating between the master node and each slave node of the array to enable synchronization of said each slave node to the master node, the step of communicating with said each slave node being performed on a radio frequency (RF) side channel link associated with said each slave node, wherein a plurality of RF side channel links are established by the array, each RF side channel link operating on an upward frequency for transmissions to the master node and on a downward frequency for transmissions from the master node;
performing frequency, time, and phase synchronization of said each slave node to the master node based on the step of communicating;
distributing across the array common data for transmission to the target; and
coherently transmitting from said each node of the array to the target signals at a common frequency, the signals at the common frequency carrying the common data, the step of coherently transmitting being performed so that the signals at the common frequency carrying the common data add constructively in a general direction from the array to the target and/or in a general location of the target, the step of coherently transmitting comprising directional beamforming or location-focusing using time-reversal;
wherein;
the plurality of slave nodes comprises a first slave node associated with a first RF side channel link, and a second slave node associated with a second RF side channel link;
the first RF side channel link operates from the first slave node to the master node on a first upward band centered round a first upward frequency and from the master node to the first slave node on a first downward band centered round a first downward frequency;
the second RF side channel link operates from the second slave node to the master node on a second upward band centered round a second upward frequency and from the master node to the second slave node on a second downward band centered round a second downward frequency; and
at least one band selected from the group consisting of the first upward band, the second upward band, the first downward band, and the second downward band is different from and non-overlapping at least one other band selected from the group.
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Accused Products
Abstract
Dynamic, untethered array nodes with internal clocks are frequency, phase, and time aligned/synchronized, and used to focus their transmissions of the same payload data coherently on a target or in the target'"'"'s direction, using time reversal or directional beamforming. Information for alignment/synchronization may be sent from a master node of the array to the slave nodes, over RF node-to-node links operating on different carrier or subcarrier frequencies. Additionally, the up- and down-communications on the RF links may use different frequencies. The RF links may also be used to distribute the payload data across the array. Because of frequency division on the RF links, interference is reduced or avoided, and the process of alignment/synchronization may be performed concurrently for several or all the slave nodes. The array may also operate collaboratively to receive data from the target.
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Citations
20 Claims
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1. A method of communicating between an array of ad hoc nodes and a target, the array comprising a master node and a plurality of slave nodes, the method comprising steps of:
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communicating between the master node and each slave node of the array to enable synchronization of said each slave node to the master node, the step of communicating with said each slave node being performed on a radio frequency (RF) side channel link associated with said each slave node, wherein a plurality of RF side channel links are established by the array, each RF side channel link operating on an upward frequency for transmissions to the master node and on a downward frequency for transmissions from the master node; performing frequency, time, and phase synchronization of said each slave node to the master node based on the step of communicating; distributing across the array common data for transmission to the target; and coherently transmitting from said each node of the array to the target signals at a common frequency, the signals at the common frequency carrying the common data, the step of coherently transmitting being performed so that the signals at the common frequency carrying the common data add constructively in a general direction from the array to the target and/or in a general location of the target, the step of coherently transmitting comprising directional beamforming or location-focusing using time-reversal; wherein; the plurality of slave nodes comprises a first slave node associated with a first RF side channel link, and a second slave node associated with a second RF side channel link; the first RF side channel link operates from the first slave node to the master node on a first upward band centered round a first upward frequency and from the master node to the first slave node on a first downward band centered round a first downward frequency; the second RF side channel link operates from the second slave node to the master node on a second upward band centered round a second upward frequency and from the master node to the second slave node on a second downward band centered round a second downward frequency; and at least one band selected from the group consisting of the first upward band, the second upward band, the first downward band, and the second downward band is different from and non-overlapping at least one other band selected from the group. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 12)
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11. An array of nodes for collaborative communication with a target, wherein:
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the array comprises a master node and a plurality of slave nodes, the plurality of slave nodes comprising a first slave node and a second slave node; each node of the array comprises a processor;
radio frequency circuitry (RF) operating under control of the processor, and memory coupled to the processor and storing instructions executable by the processor;the nodes are configured to; establish a plurality of RF side channel links, an RF side channel link per slave node, each slave node of the plurality of slave nodes communicating with the master node over the RF side channel link corresponding to said each slave node to enable frequency, time, and phase synchronization of said each slave node to the master node, each RF side channel link of the plurality of side channel links operating on an upward frequency for transmissions to the master node and on a downward frequency for transmissions from the master node, the plurality of RF side channel links comprises a first side channel link corresponding to the first slave node and a second side channel link corresponding to the second slave node, perform frequency, time, and phase synchronization of said each slave node to the master node based on the communications over the RF side channel links, distribute across the array common data for transmission to the target, and coherently transmit from said each node of the array to the target signals at a common frequency, the signals at the common frequency carrying the common data, wherein the signals carrying the common data add constructively in a general direction from the array to the target and/or in a general location of the target, wherein directional beamforming or location-focusing using time-reversal is accomplished; wherein; the first RF side channel link operates from the first slave node to the master node on a first upward band centered round a first a first upward frequency and from the master node to the first slave node on a first downward band centered round a first downward frequency; the second RF side channel link operates from the second slave node to the master node on a second upward band centered round a second upward frequency and from the master node to the second slave node on a second downward band centered round a second downward frequency; at least one band selected from the group consisting of the first upward band, the second upward band, the first downward band, and the second downward band is different from and non-overlapping with at least one other frequency selected from the group; and said each node of the array is free to move in three dimensions in absolute terms, with respect to the target, and with respect to other nodes of the array; and said each node of the array is free to rotate around a plurality of axes. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
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Specification