Massachusetts Institute of Technology

University of California

Carnegie Mellon University

Academia Sinica

Emerald Innovations, LLC

Dina Katabi

Swarun Suresh Kumar

Deepak Vasisht

Fadel Adib

Hariharan Rahul

Lixin Shi

Zachary Edward Kabelac

Omid Salehi-Abari

Haitham Zuhair Al-Hassanieh

Shyamnath Gollakota

Daniela Rus

Piotr Indyk

Stephanie Gil

Ezzeldin Hamed

Jouya Jadidian

Vladimir Marko Stojanovic

Anantha P Chandrakasan

Ching-Ju Lin

Dinesh Bharadia

Martin Conway Rinard

Jue Wang

Nathaniel A Kushman

Regina Barzilay

Srinivasan Seshan

Sai Roshan Ayyalasomayajula

Rumen Hristov

Abhinav Agarwal

Satchuthananthavale R Kuhan Branavan

Kate Ching-Ju Lin

Michael Rodriguez

Wei-Liang Shen

Sachin Katti

Zachary Kabelac

A method for wireless detection of a subject rising from a rest state includes producing transmitted wireless signals from one or more transmitting antennas, receiving reflected wireless signals at one or more receiving antennas, and processing the reflected wireless signals in a computer. The computer iteratively aligns candidate trajectories with a template trajectory until the current and previous template trajectories are within a predetermined distance from each other. A final template trajectory is used to determine a lying-down surface exit initiation area, a lying-down surface exit initiation area exit time, a TUG plane or radius entry time, and a TUG time.

System and method for wireless detection and measurement of a subject rising from rest

A method, a system, and a computer program product for determining a location of a communication device. Data corresponding to a detected transmission of a data packet between a tag device and one or more communication devices is received on one or more communication channels. At least one of a channel state information and a signal strength associated with the detected transmission for each frequency band in a plurality of frequency bands are determined. Based on the determined channel state information, one or more lengths of signal paths corresponding to the detected transmission of the data packet are determined. A shortest length in across one or more communication devices is selected to determine a location of the tag device.

Location determination of wireless communications devices

A method for wireless power transfer adapts to changing configuration of receivers, including changes in number of, location and/or orientiation of, magnetic coupling to, and load of circuits (e.g., battery charging circuits) of one or more receivers. The adaptation can be performed without interrupting optimal or near-optimal power transfer to the receivers, and can provide a measure of fairness among multiple receivers.

Adaptive control of wireless power transfer

An approach to authentication, provisioning, and/or access control makes use of a user performing prescribed motion of their body and/or particular limbs (e.g., a prescribed number of steps in one or more directions), for example, as part of a challenge-response protocol. The motion may be detected using the radio frequency reflection techniques. Applications of this approach may include provisioning of equipment that monitors motion within an environment. In some examples, the environment is defined as part of the user performing the prescribed motion (e.g., the user walks around a boundary of their house).

Security protocol for motion tracking systems

Multiple radio transmissions are processed to determine, for each of a number of directions of arrival of the radio transmissions, a most direct direction of arrival, for example, to distinguish a direct path from a reflected path from the target. In some examples, the radio transmissions include multiple frequency components, and channel characteristics at different frequencies are compared to determine the direct path.

Characterizing multipath delays in antenna array and synthetic aperture radar systems

Characteristics of channels from an antenna array to a transceiver are characterized based on reciprocity in an approach that eliminates a need for channel feedback from the transceiver. In some embodiments, these channel characteristics are used in MIMO communication to a plurality of transceivers from the antenna array.

Characterizing transmit channels from an antenna array to a transceiver

A method for monitoring periodic motions of one or more subjects uses signal reflections from the subjects. The method includes emitting a transmitted signal from a transmitting antenna and receiving a received signal at one or more receiving antennas. The received signal includes a combination of a number of reflections of the transmitted signal, at least some of which are associated with the subjects. The received signal, including the reflections, is processed to determine an estimate of a fundamental frequency of the periodic motions.

Vital signs monitoring via radio reflections

An approach to acquisition of a propagation direction using a phased antenna array avoids a need to scan space. Given all possible directions for setting the antenna beam, the approach provably finds the optimal direction in logarithmic number of measurements. Further, the approach can be applied within the existing 802.11ad standard for mmWave LAN, and can support both clients and access points.

Hash based beam alignment

A method includes determining, by a base station including a number of transmitting coils, a first number of mutual magnetic parameters, each mutual magnetic parameter being associated with one of the transmitting coils and a receiving coil of at least one receiving coil associated with at least one electronic device remotely located from and to be remotely charged by the base station, determining a plurality of control signals based on the first number of mutual magnetic parameters, each control signal being associated with a corresponding one of the transmitting coils, providing each control signal to a driving circuit coupled to the control signal's corresponding transmitting coil, and using each control signal to cause the driving circuit coupled to the control signal's corresponding transmitting coil to cause a current with a magnitude and phase determined from the control signal to flow in the corresponding transmitting coil.

Wireless power transfer

Directional characterization of a location of a target device makes use of multiple radio transmissions that are received from the target device. In some examples, each radio transmission is received at a first antenna at a fixed location, and is also received at a second moving antenna. The received transmissions are combined to determine the directional characterization, for example, as a distribution of power as a function of direction. In some examples, the received radio transmissions are processed to determine, for each of a plurality of directions of arrival of the radio transmissions, a most direct direction of arrival, for example, to distinguish a direct path from a reflected path from the target.

Localization with non-synchronous emission and multipath transmission

A system for localization of a radio frequency source in a region includes a first plurality of antennas disposed about the region, a second plurality of antennas disposed about the region, a first radio frequency positioning module in communication with the first plurality of antennas and configured to determine a plurality of spatially separated candidate locations in the region for the radio frequency source, a second radio frequency positioning module in communication with the second plurality of antennas and configured to determine a sub-region of the region, the sub-region including the radio frequency source, and a resolution module for identifying a subset of the candidate locations in the sub-region of the region.

Radio frequency localization

A system enables a single WiFi access point to localize clients to within tens of centimeters. Such a system can bring indoor positioning to homes and small businesses which typically have a single access point. A key enabler underlying the system is a novel algorithm that can compute sub-nanosecond time of flight using commodity WiFi cards. By multiplying the time of flight with the speed of light, a Wifi access point computes the distance between each of its antennas and the client, hence localizing it. An implementation on commodity WiFi cards demonstrates that the system's accuracy is comparable to state-of-the-art localization systems, which use four or five access points.

Sub-decimeter radio frequency ranging

An approach to localization in an indoor environment makes use of a multiple antenna receiver (e.g., in a smartphone, tablet, camera) and knowledge of locations of one or more radio transmitters, which may be part of a data communication infrastructure providing data communication services to devices in the environment. Successive measurements of transmissions from the transmitters are recorded at the receiver as the device is translated and rotated in the environment. Rotation related measurements are also made at the device. The radio frequency and rotation related measurements are used to infer the location and orientation, together referred to as the pose, of the device. Phase synchronization of the transmitters and the receiver are not required. In general, accuracy of the pose estimate far exceeds that achievable using radio frequency measurements without taking into consideration motion of the device, and far exceeds that achievable using the inertial measurements alone.

Indoor localization of a multi-antenna receiver

A method for wireless power transfer adapts to changing configuration of receivers, including changes in number of, location and/or orientation of, magnetic coupling to, and load of circuits (e.g., battery charging circuits) of one or more receivers. The adaptation can be performed without interrupting optimal or near-optimal power transfer to the receivers, and can provide a measure of fairness among multiple receivers.

An approach to adaptively positioning a set of mobile routers to provide communication services to a set of clients makes use of estimated direction profiles of communication between routers and clients. The approach does not rely on a Euclidean model in which communication characteristics (e.g., signal strength, data rate, etc.) depend on distance between communicating nodes, and does not necessarily require sampling of communication characteristics in unproductive directions in order to move the routers to preferable locations.

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Cambridge, MA, United States of America

Dina Katabi