Origin Wireless, Inc.

Hang Ma

K J Ray Liu

Yan Chen

Yi Han

Hung-Quoc Duc Lai

Zoltan Safar

Feng Han

Beibei Wang

Chen Chen

Qinyi Xu

Zhung-Han Wu

Yu-Han Yang

The predicted explosive growth in the number of wireless devices and mobile applications utilizing wireless networks makes it time for engineers to face the high network densification challenge where massive numbers of terminal devices (TDs) coexist and require both high-rate and low-latency wireless data transmissions. We describe a multiple access point (AP) Time-Reversal Division Multiple Access (TRDMA) downlink system that utilizes the natural spatial and temporal focusing properties of Time Reversal (TR) based communications, where the interference to unintended receivers is automatically at least partially mitigated. As a result, in some implementations, the TRDMA system can achieve full or nearly-full spectrum reuse without any coordination among APs. The performance of the TRDMA system is investigated in both an open access model where an AP is open to all the TDs and a closed access model where an AP is only open to specific TDs. It is shown that in the open access model, the TRDMA system can be easily extended by adding more APs to fit various scenarios. In the closed access model, the TRDMA system is failure-robust such that the performance degradation caused by neighboring APs is graceful. Moreover, the packet delay of the TRDMA system can be much lower than that of the IEEE 802.11 based system.

Time-reversal scalability for high network densification

An apparatus for determining symbol timing in a communication system is provided. The apparatus includes a memory communicatively coupled to at least one processor. The at least one processor is configured to receive a first signal that includes a preamble sent at a first sampling rate with a first modulation through a channel and a data frame sent at a second sampling rate with a second modulation through the channel. The preamble includes a received code sequence, and the data frame includes a plurality of data symbols. The at least one processor is configured to compute a second signal that represents an estimate of an equivalent channel response using at least one of a known code sequence and the received first signal, down-sample the second signal and compute signal-to-interference-plus-noise ratios at a plurality of candidate timing offsets, and determine a symbol timing based on a particular timing offset associated with one of the computed signal-to-interference-plus-noise ratios.

Time-reversal communication systems

Transmitters and receivers for use in hybrid networks capable of supporting time-reversal division multi-access communication protocols are described. Wireless access points include a wireless receiver for receiving a wireless channel probe signal from a device and a wireless transmitter capable of supporting a time-reversal division multi-access (TRDMA) protocol and at least one other wireless communication protocol. A controller is used to control the operation of the wireless transmitter. Wireless terminal devices include a wireless transmitter for transmitting a wireless channel probe signal and a wireless receiver capable of supporting a TRDMA protocol and at least one other wireless communication protocol. A controller is used to control the operation of the wireless receiver. An example of the at least one other wireless communication protocol that may be supported is OFDMA. Network performance can be improved by using wireless access points and terminal devices that switch between supporting one wireless communication protocol or another or supporting multiple wireless communication protocols simultaneously.

Time-reversal technologies for hybrid wireless networks

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.

Handshaking protocol for time-reversal system

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.

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Greenbelt, MD, United States of America

Hang Ma