Methods, apparatus and systems for wireless motion recognition are described. In one example, a described system comprises: a transmitter configured for transmitting a first wireless signal through a wireless multipath channel of a venue; a receiver configured for receiving a second wireless signal through the wireless multipath channel; and a processor. The second wireless signal differs from the first wireless signal due to the wireless multipath channel that is impacted by a motion of an object in the venue. The processor is configured for: obtaining a time series of channel information (TSCI) of the wireless multipath channel based on the second wireless signal, tracking the motion of the object based on the TSCI to generate a gesture trajectory of the object, and determining a gesture shape based on the gesture trajectory and a plurality of pre-determined gesture shapes.

A transmitter of a radar system repeatedly transmits a first OFDM symbol into a scene to be characterized during a first time interval, and repeatedly transmits, during a second time interval that occurs after the first time interval, a second OFDM symbol into the scene. A receiver of the radar system generates a first channel response estimate for a first section of the scene based on: received reflections of the first symbol, at least one of which was received during transmission of the second OFDM symbol in the second time interval, and a first channel response estimate for a second section of the scene based on the first channel response estimate for the first section of the scene, received reflections of the first symbol, and received reflections of the second symbol. The receiver detects objects present in the scene based on the first channel response estimate for the first section of the scene and the first channel response estimate for the second section of the scene.

Methods and devices for estimating an angle between a transmitter and a receiver for beamforming are provided. A method includes, with an antenna element in a first device, transmitting an omnidirectional pulse and detecting an echo of the pulse reflected from a second device. An angle between the first device and the second device is estimated based at least on a characteristic of the echo. The method includes transmitting the angle to the second device for use in beamforming between the first device and the second device.

In an example method, a vehicle configured to operate in an autonomous mode could have a radar system used to aid in vehicle guidance. The method could include transmitting at least two signal pulses. The method further includes, for each transmitted signal pulse, receiving a reflection signal associated with reflection of the respective transmitted signal pulse. Each reflection signal may be received when the apparatus is in a different respective location. Additionally, the method includes processing the received reflection signals to determine target information relating to one or more targets in an environment of the vehicle. Also, the method includes correlating the target information with at least one object of a predetermined map of the environment of the vehicle to provide correlated target information. Yet further, the method includes storing the correlated target information for the at least one object in an electronic database.

A vehicle radar system, such as a multiple input multiple output (MIMO) radar system, for estimating a Doppler frequency shift and a method of using the same. In one example, a modulated signal is mixed with an orthogonal code sequence and is transmitted by a transmit antenna array with a plurality of transmitting antennas. The signals reflect off of a target object and are received by a receive antenna array with a plurality of receiving antennas. Each of the received signals, which likely includes a Doppler frequency shift, is processed and mixed with a number of frequency shift hypotheses that are intended to offset the Doppler frequency shift and result in a series of correlation values. The frequency shift hypothesis with the highest correlation value is selected and used to correct for the Doppler frequency shift so that more accurate target object parameters, such as velocity, can be obtained.

A method of environmental sensing through pilot signals in a spread spectrum wireless communication system is provided with a plurality of wireless terminals. The plurality of wireless terminals includes a plurality of multi-input multi-output (MIMO) radars and at least one base station. The plurality of terminals broadcasts a beacon pilot signals containing a terminal-specific information and encoded with a corresponding identifier. Using the corresponding identifier, an arbitrary radar from the plurality of MIMO radars separates the beacon pilot signal from an ambient signal. More specifically, the arbitrary radar compares the ambient signal to the corresponding identifier of each wireless terminal to identify at least one origin terminal. Subsequently, the arbitrary radar extracts the terminal-specific information from the beacon pilot signal of the origin terminal. The terminal-specific information is used to exchange data between the plurality of wireless terminals for autonomous driving.

A radar device includes: a control circuit which, in operation, selects at least one of a plurality of transmission antennas in each of determined transmission periods; and a plurality of transmission circuits which, in operation, transmit at least one transmission signal in every transmission period using the selected at least one of the plurality of transmission antennas. The control circuit, in operation, selects a first transmission antenna of the plurality of transmission antennas once in the determined transmission periods, and selects remaining second transmission antennas of the plurality of transmission antennas a plurality of times in the determined transmission periods.

A system is provided for joint communication and radar sensing. The system includes at least one communication transmitter unit configured to transmit at least one communication pilot signal, at least one radar transmitter unit configured to transmit at least one radar pilot signal, a control unit configured to schedule the transmission of the at least one communication transmitter unit and/or the at least one radar transmitter unit using a time delay, and at least one receiver unit configured to receive the at least one radar pilot signal with the time delay with respect to the at least one communication pilot signal. A method of using the system for joint communication and radar sensing is also provided.

An illustrative example embodiment of a detector device includes a receiver configured to receive radiation comprising a plurality of codes. Each of the codes is associated with one of a plurality of transmissions and each of the codes is distinct from the other codes. A processor is configured to obtain information corresponding to at least one predetermined phase code spectrum for the codes, determine a demodulated signal spectrum of radiation received by the at least one receiver, determine at least one characteristic of the determined demodulated signal spectrum, adjust the at least one predetermined phase code spectrum based on the determined characteristic to generate an adjusted phase code spectrum, and refine the determined demodulated signal spectrum based on the adjusted phase code spectrum to generate a refined demodulated signal spectrum.

A transmitting array antenna includes a second antenna group placed in a position inside a first antenna group in a first direction and a position different from the first antenna group in a second direction. A receiving array antenna includes a fourth antenna placed in a position outside a third antenna group arranged in the first direction and a position different from the third antenna group in the second direction. An interelement spacing between a receiving antenna of the third antenna group located at an end on a second side is identical to an interelement spacing in the first direction between a transmitting antenna of the first antenna group on the first side and each of the second antenna group. In a case where the first antenna group and the third antenna group are identical in position in the second direction, positions of antennas are different.