Systems and methods for a full-duplex backscatter system. An example method includes outputting, via a transmitter of the backscatter system, a single tone carrier for transmission via an antenna of the backscatter system. A tunable impedance network is tuned via a microcontroller to reduce self-interference associated with the signal tone carrier by at least a threshold level, with the tunable impedance network including passive elements which are configured to be tuned, and with the self-interference reduction by the threshold level being in the analog domain. Backscatter data packets are received via a receiver from backscatter tags, with the backscatter data packets being associated with an offset frequency and are decoded by the receiver.

Systems and methods for a full-duplex backscatter system. An example method includes outputting, via a transmitter of the backscatter system, a single tone carrier for transmission via an antenna of the backscatter system. A tunable impedance network is tuned via a microcontroller to reduce self-interference associated with the signal tone carrier by at least a threshold level, with the tunable impedance network including passive elements which are configured to be tuned, and with the self-interference reduction by the threshold level being in the analog domain. Backscatter data packets are received via a receiver from backscatter tags, with the backscatter data packets being associated with an offset frequency and are decoded by the receiver.

A communications system including a transmit processor for determining transmit and azimuth elevation in response to a refractive layer altitude, a transmitter array including a plurality of transmitters each for transmitting one of a plurality of transmitted signals in response to the transmit elevation wherein each of the plurality of transmitted signals is encoded using a data signal and one of a plurality of unique synchronization sequences, and a receiver for receiving the plurality of transmitted signals, isolating each of the plurality of transmitted signals in response to one of the plurality of unique synchronization sequences corresponding to each of the plurality of transmitted signals to generate a plurality of isolated signals, to combine the plurality of isolated signals to generate a combined signal and to generate the data signal in response to the combined signal.

A communications system including a transmit processor for determining transmit and azimuth elevation in response to a refractive layer altitude, a transmitter array including a plurality of transmitters each for transmitting one of a plurality of transmitted signals in response to the transmit elevation wherein each of the plurality of transmitted signals is encoded using a data signal and one of a plurality of unique synchronization sequences, and a receiver for receiving the plurality of transmitted signals, isolating each of the plurality of transmitted signals in response to one of the plurality of unique synchronization sequences corresponding to each of the plurality of transmitted signals to generate a plurality of isolated signals, to combine the plurality of isolated signals to generate a combined signal and to generate the data signal in response to the combined signal.

Disclosed is a first portable electronic device for facilitating a proximity based interaction with a second portable electronic device based on a plurality of gestures. The first portable electronic device includes at least one first sensor device configured to generate at least one of a first sensor data, a second sensor data, and a third sensor data, a first transceiver configured for communicating with a second transceiver associated with the second portable electronic device, and a first processor configured for detecting a pre-tap gesture based on the first sensor data, entering the first portable electronic device in an interaction mode based on the detecting of the pre-tap gesture, detecting a proximity based event based on the second sensor data, performing a predetermined action, detecting a post-tap gesture, determining if the post-tap gesture is detected within a predetermined time period, and performing one of an acceptance and a rejection of the predetermined action based on the determining.

Disclosed is a first portable electronic device for facilitating a proximity based interaction with a second portable electronic device based on a plurality of gestures. The first portable electronic device includes at least one first sensor device configured to generate at least one of a first sensor data, a second sensor data, and a third sensor data, a first transceiver configured for communicating with a second transceiver associated with the second portable electronic device, and a first processor configured for detecting a pre-tap gesture based on the first sensor data, entering the first portable electronic device in an interaction mode based on the detecting of the pre-tap gesture, detecting a proximity based event based on the second sensor data, performing a predetermined action, detecting a post-tap gesture, determining if the post-tap gesture is detected within a predetermined time period, and performing one of an acceptance and a rejection of the predetermined action based on the determining.

A communication system uses multiple communications links, preferably links that use different communications media. The multiple communications links may include a high latency/high bandwidth link using a fiber-optic cable configured to carry large volumes of data but having a high latency. The communications links may also include a low latency/low bandwidth link implemented using skywave propagation of radio waves and configured to carry smaller volumes of triggering data with a lower latency across a substantial portion of the earth's surface. The triggering data may be sent in a data stream as data frames without headers, security information, or error checking codes. The two communications links may be used together to coordinate various activities such as the buying and selling of financial instruments.

A receiver includes a circuit designed to process, based on a plurality of timed waveform reference locations, a waveform signal, the waveform signal comprising a message. The circuit may include a clock source, an input configured to receive the waveform signal, a time location reference circuit coupled to the clock source, the time location reference circuit designed to output the plurality of timed waveform reference locations, each timed waveform reference location being set by the clock, and a signal processing circuit coupled to the time location reference circuit, the signal processing circuit designed to generate an output voltage in a response to the waveform signal being inputted into the signal processing circuit through the input and processed at each timed waveform reference location from the series of timed waveform reference locations. A transmitter that generates the waveform signal can be also provided where the clocks are matched.

Technology for wireless transmission of messages to remote receiving devices is disclosed. The technology includes receiving a message for transmission, determining transmission parameters for transmission of the message, and transmitting the message to a remote receiving device according to the determined transmission parameters. The technology may also include encoding the message to effect message latency and may be employed for message transmission via the ionosphere or other atmospheric layer at frequencies in the Medium Frequency (MF), High Frequency (HF), or Very High Frequency (VHF) spectrum. Further, the disclosed technology may be employed for message transmission to effect low latency financial transaction execution, such as high speed high frequency trading.

A communication system uses skywave propagation to transmit data between communication nodes over a data transmission path. An atmospheric sensor is configured to collect atmospheric data at the reflection point of the data transmission path where the transmission path is redirected from the atmosphere toward the surface of the Earth. Data collected by the atmospheric sensor may be used to predict future ionospheric conditions and determine optimum working frequencies for transmission of data between the communication nodes.