Abstract: 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.

Abstract: An ASIC for monitoring wideband GHz spectrum to sense respective frequency components present in the spectrum. The ASIC implements Fast Fourier Transform (FFT) techniques to facilitate identification of one or more frequency components of a sparse signal after the signal is sub-sampled at a rate below the Nyquist criterion. The ASIC computes a first Fast Fourier Transform (FFT) of a first sub-sampled set of samples of a time-varying signal representing the monitored spectrum and sampled at a first sampling rate, and further computes a second FFT of a second sub-sampled set of samples of the time-varying signal sampled at a second sampling rate different from the first sampling rate. In one example, each of the first FFT and the second FFT is a low-radix FFT to facilitate a low-power and low-cost ASIC implementation of wideband spectrum sensing.

Abstract: An offset estimator (e.g., a time delay, a spatial image offset, etc.) makes use of a transform approach (e.g., using Fast Fourier Transforms). The sparse nature of a cross-correlation is exploited by limiting the computation required in either or both of the forward and inverse transforms. For example, only a subset of the transform values (e.g., a regular subsampling of the values) is used. In some examples, an inverse transform yields a time aliased version of the cross-correlation. Further processing then identifies the most likely offset of the original signals by considering offsets that are consistent with the aliased output.

Abstract: A number of techniques, which may be used together, provide distributed coordination of multiple stations so that concurrent transmissions and increased throughput are achieved on a shared radio medium. Each of the techniques provides a separate innovation that can be used alone or in combination with one or more of the other techniques.

Abstract: A distributed wireless communication system includes multiple access points, each with one or more antennas. The access points do not necessarily have synchronized transmitting and receiving radio frequency oscillators. Approaches to channel estimation between the access points and one or more wireless clients account for the lack of synchronization, and do not necessarily require capabilities at the clients that go beyond required or optional features of standard wireless Ethernet (e.g., 802.11n, 802.11g, or 802.11a), thereby supporting “legacy” clients while supporting high data throughput approaches that provide coherent transmission from the multiple antenna of the access points.

Abstract: A system and method that enables a plurality of lay users to collaborate on automating computer tasks is disclosed. In one embodiment, the system automatically performs these tasks, rather than just documenting how to perform them. The system allows a database of solutions to be built for every important computer task. A key characteristic of this system is that users contribute to this database by simply performing the task. The system records the graphical user interface (GUI) actions as the user performs the task. It aggregates GUI traces from multiple users into a canonical sequence of GUI actions parameterized by user-environment that will successfully accomplish the task on a variety of different configurations. A classifier is used to predict which steps are likely to be misinterpreted and requests human intervention to properly perform them. This process can be done iteratively until the translation is believed to be correct.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: Dynamic adaption of transmission rate for multiuser MIMO networks is disclosed. The invention controls a first communication device to transmit data at rates optimal determined under the condition that the channel is occupied by the first communication device, a second communication device to transmit data at rates optimal determined under the condition that the channel is shared by the first and second communication devices and a third communication to transmit data at rates optimal determined under the condition that the channel is shared by the first, second and third communication device.

Abstract: 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.

Abstract: An ASIC for monitoring wideband GHz spectrum to sense respective frequency components present in the spectrum. The ASIC implements Fast Fourier Transform (FFT) techniques to facilitate identification of one or more frequency components of a sparse signal after the signal is sub-sampled at a rate below the Nyquist criterion. The ASIC computes a first Fast Fourier Transform (FFT) of a first sub-sampled set of samples of a time-varying signal representing the monitored spectrum and sampled at a first sampling rate, and further computes a second FFT of a second sub-sampled set of samples of the time-varying signal sampled at a second sampling rate different from the first sampling rate. In one example, each of the first FFT and the second FFT is a low-radix FFT to facilitate a low-power and low-cost ASIC implementation of wideband spectrum sensing.

Abstract: In one aspect, a distributed coherent transmission system enables transmissions from separate wireless transmitters with independent frequency or clock references to emulate a system where all the transmitters share a common frequency or clock reference. Differences in frequency and/or phase between transmitters are addressed by suitably precoding signals before modulation at one or more of the transmitters based on a synchronizing transmission from one of the transmitters (e.g., a master transmitter) received at a corresponding receiver sharing the frequency or clock reference with each of the one or more transmitters. Such a distributed coherent transmission system can allow N single-antenna transmitters with independent frequency or clock references to emulate a single N-antenna Multi Input Multi Output (MIMO) transmitter, or implement schemes such as distributed superposition coding or lattice codes that require coherence across separate transmitters.

Abstract: In one aspect, a method for mitigating an effect of an interfering radio signal at a multiple antenna receiver includes forming an estimate of a relationship of the interfering signal among signals received from the multiple antennas. In general, the interfering signal does not share the same communication technology as a desired signal. The signals received from the multiple antennas filtered and combined according to the estimate of the relationship of the interfering channels to reduce an effect of the interfering signal. Desired data present in the desired signal represented in the filtered and combined signals is decoded and the estimate of the relationship of the interfering signals is updated according to the decoding of the desired signal.

Abstract: Dynamic adaption of transmission rate for multiuser MIMO networks is disclosed. The invention controls a first communication device to transmit data at rates optimal determined under the condition that the channel is occupied by the first communication device, a second communication device to transmit data at rates optimal determined under the condition that the channel is shared by the first and second communication devices and a third communication to transmit data at rates optimal determined under the condition that the channel is shared by the first, second and third communication device.

Abstract: An offset estimator (e.g., a time delay, a spatial image offset, etc.) makes use of a transform approach (e.g., using Fast Fourier Transforms). The sparse nature of a cross-correlation is exploited by limiting the computation required in either or both of the forward and inverse transforms. For example, only a subset of the transform values (e.g., a regular subsampling of the values) is used. In some examples, an inverse transform yields a time aliased version of the cross-correlation. Further processing then identifies the most likely offset of the original signals by considering offsets that are consistent with the aliased output.

Abstract: A distributed wireless communication system includes multiple access points, each with one or more antennas. The access points do not necessarily have synchronized transmitting and receiving radio frequency oscillators. Approaches to channel estimation between the access points and one or more wireless clients account for the lack of synchronization, and do not necessarily require capabilities at the clients that go beyond required or optional features of standard wireless Ethernet (e.g., 802.11n, 802.11g, or 802.11a), thereby supporting “legacy” clients while supporting high data throughput approaches that provide coherent transmission from the multiple antenna of the access points.

Abstract: In one aspect, a distributed coherent transmission system enables transmissions from separate wireless transmitters with independent frequency or clock references to emulate a system where all the transmitters share a common frequency or clock reference. Differences in frequency and/or phase between transmitters are addressed by suitably precoding signals before modulation at one or more of the transmitters based on a synchronizing transmission from one of the transmitters (e.g., a master transmitter) received at a corresponding receiver sharing the frequency or clock reference with each of the one or more transmitters. Such a distributed coherent transmission system can allow N single-antenna transmitters with independent frequency or clock references to emulate a single N-antenna Multi Input Multi Output (MIMO) transmitter, or implement schemes such as distributed superposition coding or lattice codes that require coherence across separate transmitters.

Abstract: A number of techniques, which may be used together, provide distributed coordination of multiple stations so that concurrent transmissions and increased throughput are achieved on a shared radio medium. Each of the techniques provides a separate innovation that can be used alone or in combination with one or more of the other techniques.

Abstract: In one aspect, a method for mitigating an effect of an interfering radio signal at a multiple antenna receiver includes forming an estimate of a relationship of the interfering signal among signals received from the multiple antennas. In general, the interfering signal does not share the same communication technology as a desired signal. The signals received from the multiple antennas filtered and combined according to the estimate of the relationship of the interfering channels to reduce an effect of the interfering signal. Desired data present in the desired signal represented in the filtered and combined signals is decoded and the estimate of the relationship of the interfering signals is updated according to the decoding of the desired signal.