Patent application number | Description | Published |
20130159722 | ACTIVE SENSING FOR DYNAMIC SPECTRUM ACCESS - Various communication systems may benefit from physical layer watermarking. For example, active sensing for dynamic spectrum access may be performed using physical layer watermarking, such as watermarking based on channel effects and/or receiver distortion. A method may include, for example, obtaining an original signal to be transmitted to at least one receiver. The method may also include watermarking the original signal with at least one of authentication data or ancillary data to provide an enhanced signal. The watermarking can include a physical layer watermark. The physical layer watermark can be configured to emulate at least one a channel effect or a receiver distortion. The method can further include transmitting the enhanced signal to the at least one receiver. | 06-20-2013 |
20150049745 | TIME-REVERSAL WIRELESS SYSTEMS HAVING ASYMMETRIC ARCHITECTURE - In an asymmetric time-reversal wireless system, a base station includes an input circuit configured to, during a hand-shake period, receive a channel response signal derived from a probe signal sent from a first terminal device to the apparatus through multiple wireless propagation paths, and during an uplink transmission period, receive combined signals that include a signal from the first terminal device and a signal from a second terminal device. The base station includes a data processor configured to calculate a signature waveform for the first terminal device based on the channel response, and determine the signal sent from the first terminal device during the uplink transmission period based on the combined signals and the signature waveform for the first terminal device. | 02-19-2015 |
20150049792 | MULTIUSER TIME-REVERSAL DIVISION MULTIPLE ACCESS UPLINK SYSTEM WITH PARALLEL INTERFERENCE CANCELLATION - In a time-reversal wireless system, a transceiver receives a combined signal that includes signals from a plurality of devices, each device sending a signal to the transceiver through multiple wireless propagation paths. Signals sent from each of the devices are estimated based on the combined signal and a signature waveform associated with the device. Interference associated with the estimated signal from each of the devices is determined based on the estimated signals from the devices. The signal sent from each of the devices is determined by subtracting the interference associated with the estimated signal associated with the device from the estimated signal associated with the device. | 02-19-2015 |
20150236848 | HANDSHAKING PROTOCOL FOR TIME-REVERSAL SYSTEM - A handshaking process for time-reversal wireless communication is provided. A first device receives a handshake signal transmitted from a second device through multiple propagation paths, the handshake signal including a preamble and a training sequence, in which the training sequence includes a sequence of symbols known to the first and second devices. A synchronization index is determined based on the preamble, and the training sequence in the handshake signal is identified based on the synchronization index. A channel response signal is determined based on the received training sequence, and a signature waveform that is a time-reversed signal of the channel response signal is generated. A transmission signal is generated based on transmit data and the signature waveform, in which the transmit data are data configured to be transmitted to the second device. | 08-20-2015 |
20150257167 | TIME-REVERSAL WIRELESS PARADIGM FOR INTERNET OF THINGS - A method of connecting devices to a network is provided. The method includes providing base stations connected to a network, and at each of the base stations, receiving probe signals from terminal devices. For each of the terminal devices, the base station calculates a signature waveform based on a time-reversed waveform of a channel response signal derived from the corresponding probe signal. For each of the terminal devices, the base station determines a downlink transmit signal for the terminal device based on the downlink data and the corresponding signature waveform, and transmits the downlink signals to the terminal devices. Several base stations have overlapping broadcast regions, several terminal devices are located within the overlapped broadcast regions, the base stations transmit the downlink signals using a same frequency band, and some downlink signals transmitted by base stations having overlapping broadcast regions also overlap in time. | 09-10-2015 |
20150312081 | QUADRATURE AMPLITUDE MODULATION FOR TIME-REVERSAL SYSTEMS - Time-reversal wireless communication includes: at a base station, receiving a probe signal from a terminal device; generating a signature waveform that is based on a time-reversed signal of a channel response signal derived from the probe signal; performing quadrature amplitude modulation (QAM) on a transmit signal to generate a quadrature amplitude modulated signal; and generating a transmission signal based on the quadrature amplitude modulated signal and the signature waveform. | 10-29-2015 |
20160081060 | TIME-REVERSAL WIRELESS PARADIGM FOR INTERNET OF THINGS - A method of connecting devices to a network is provided. The method includes providing base stations connected to a network, and at each of the base stations, receiving probe signals from terminal devices. For each of the terminal devices, the base station calculates a signature waveform based on a time-reversed waveform of a channel response signal derived from the corresponding probe signal. For each of the terminal devices, the base station determines a downlink transmit signal for the terminal device based on the downlink data and the corresponding signature waveform, and transmits the downlink signals to the terminal devices. Several base stations have overlapping broadcast regions, several terminal devices are located within the overlapped broadcast regions, the base stations transmit the downlink signals using a same frequency band, and some downlink signals transmitted by base stations having overlapping broadcast regions also overlap in time. | 03-17-2016 |