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Chen Y.,Origin Wireless Communications Inc. | Chen Y.,University of Maryland University College | Han F.,Origin Wireless Communications Inc. | Han F.,University of Maryland University College | And 16 more authors.
IEEE Internet of Things Journal | Year: 2014

In this paper, we present an overview of the time-reversal (TR) wireless paradigm for green Internet of Things (IoT). It is shown that the TR technique is a promising technique that focuses signal waves in both time and space domains. The unique asymmetric architecture significantly reduces the cost of the terminal devices, the total number of which is expected to be very large for IoT. The focusing effect of the TR technique can harvest the energy of all the multi-paths at the receiver, which improves the energy efficiency of the wireless transmission and thus the battery life of terminal devices in IoT. Facilitated by the high-resolution spatial focusing, the TR division multiple access scheme leverages the uniqueness of the multi-path profiles in the rich-scattering environment and maps them into location-specific signatures, so that spatial multiplexing can be achieved for multiple users operating on the same spectrum. In addition, the TR system can easily support heterogeneous terminal devices by providing various quality-of-service (QoS) options through adjusting the waveform and rate backoff factor. Finally, the unique location-specific signature in TR system can provide additional physical-layer security and thus can enhance the privacy and security of customers in IoT. All the advantages show that the TR technique is a promising paradigm for IoT. © 2014 IEEE.


Han Y.,Origin Wireless Communications Inc. | Han Y.,University of Maryland University College | Chen Y.,Origin Wireless Communications Inc. | Chen Y.,University of Maryland University College | And 2 more authors.
2014 IEEE Global Conference on Signal and Information Processing, GlobalSIP 2014 | Year: 2014

The success of time-reversal (TR) technique relies on the design of TR signature from the multi-path profile. In practice, the signature is of limited precision instead of being infinite due to the finite resolution in hardware. Such limited signature precision will degrade the TR focusing effect and thus the system performance. Although several works have been proposed to study the performance of TR system with one-bit signature, a general relation between the resolution of signature and the system performance has not been established to answer the question: how many bits are needed for TR systems to achieve desirable system performance? In the paper, we address the question by studying the TR system with limited signature precision. We derive theoretically the relationship between the received signal-to-interference-plus-noise ratio (SINR) and the quantization step. Through simulations, we find that for a typical TR system, 4-bit resolution for the signature is good enough to achieve good system performance. © 2014 IEEE.


Trademark
Origin Wireless Inc and Origin Wireless Communications Inc. | Date: 2015-01-26

Broadband wireless equipment, namely, telecommunications base station equipment for cellular and fixed networking and communications applications; Computer hardware for wireless content delivery; Computer software for wireless content delivery; Devices for wireless radio transmission.


Patent
Origin Wireless Communications Inc. | Date: 2014-02-19

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.


Patent
Origin Wireless Communications Inc. | Date: 2014-03-10

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.


Patent
Origin Wireless Communications Inc. | Date: 2014-04-25

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.


Patent
Origin Wireless Communications Inc. | Date: 2013-08-16

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.


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.


Patent
Origin Wireless Communications Inc. | Date: 2015-02-06

A base station having an input module for receiving a probe signal sent from a terminal device, and a data processor for generating a signature waveform that is based on channel information derived from the probe signal, identifying data symbols intended to be transmitted to the terminal device, and modifying the data symbols based on the channel information. The modification of the data symbols is designed to reduce inter-symbol interference when the data symbols are received by the terminal device. The data processor generates a downlink signal based on the modified data symbols and the signature waveform. The base station generates a wide-band a radio frequency signal based on the downlink signal and transmits the radio frequency signal to the terminal device through a multipath channel such that a portion of the radio frequency signal intended for the terminal device focuses at the terminal device.


Patent
Origin Wireless Communications Inc. | Date: 2015-01-26

A time-reversal positioning system includes a storage storing first data representing channel impulse responses derived from probe signals sent from a plurality of positions and second data representing coordinates of the positions. A data processor determines a position of a terminal device based on the stored channel impulse responses and a time-reversed signal determined based on a time-reversed version of a channel impulse response that is estimated based on a channel probing signal sent from the terminal device.

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