In receiving radio waves from a transmitter by an array antenna, and estimating an arrival direction of a direct wave, delay times of the arriving waves are estimated (13) by means of a super-resolution process based on transmission channel estimation results, an arriving wave component corresponding to the delay time having been determined to be equal to or longer than a threshold value is removed (15) from the transmission channel estimation results, arriving wave components after the removal are separated from each other to extract direct wave components (17), and an arrival angle is estimated (19). The arrival direction of the direct wave can be accurately estimated in an environment where delayed waves of short delay times are present. Also, the amount of calculation is small even when the super-resolution process is performed.

A device may obtain an input symbol sequence for transmission. The device may further obtain a set of DPS sequences associated with N.sub.i highest eigenvalues of a Slepian matrix and a set of extended sequences comprising the set of DPS sequences appended with extension symbols derived based on a convolution of respective DPS sequences. The device may modulate the set of extended sequences based on the input symbol sequence to generate a signal comprising Slepian-based waveform symbol(s). Another device may receive the signal, remove the extension symbols, and demodulate Slepian-based waveform symbol(s) of the signal based on the set of DPS sequences.

A structure detection system and method for detecting anomalies associated with the structure are provided. The system includes a first transceiver, a second transceiver, and a processor. In a first TR test, the second transceiver receives a first probing signal sent from the first transceiver and performs a time-reversal (TR) process to generate a first TR signal to be sent to the first transceiver, and a first channel state information (CSI) is obtained in response to the first TR signal. In a second TR test, the first transceiver receives a second probing signal sent from the second transceiver and performs the TR process to generate a second TR signal to be sent to the second transceiver, a second CSI is obtained in response to the second TR signal. The processor compares a combination of the first CSI and the second CSI to a reference CSI for detecting anomalies.

An iterative two dimension equalizer usable in a receiver of orthogonal time frequency space (OTFS) modulated signals is described. In one configuration of the equalizer, a forward path generates, from received time-frequency domain samples and a channel estimate, estimates of data bits and likelihood numbers associated with the estimates of data bits, generated by delay-Doppler domain processing. In the feedback direction, the estimates of data bits are used to generate symbol estimates and autocorrelation matrix estimate in the time domain. In another configuration, a soft symbol mapper is used in the feedback direction for directly generating the feedback input symbol estimate without having to generate estimates of data bits.

A computer-implemented method (1400) performed in a radio access network (1510) for secondary carrier prediction is provided. The method includes obtaining (1402) an uplink channel impulse response based on a reference signal transmitted by a user equipment (UE) (104) over a primary carrier link to a serving network node (102) in a primary cell (102) currently serving the UE (104). The method includes extracting (1404) one or more features from the uplink channel impulse response. The method includes predicting (1406) an existence or non-existence of a secondary carrier link between the UE (104) and a target network node in a secondary cell (106) based on the extracted one or more features. The method includes determining (1408) whether to perform a handover procedure of the UE (104) from the serving network node in the primary cell (102) to the target network node in the secondary network cell (106) based on the predicting.

In a general aspect, a set of observed frequency-domain channel responses is filtered to remove noise or distortions that are not related to changes in the physical environment. In some aspects, for each frequency-domain channel response, a time-domain channel response is generated based on the frequency-domain channel response; and a filtered time-domain channel response is generated based on a constraint applied to the time-domain channel response. Additionally, a reconstructed frequency-domain channel response is generated based on the filtered time-domain channel response. An error signal is also generated, and a determination is made as to whether the error signal satisfies a criterion. The error signal can be indicative of a difference between the frequency-domain channel response and the reconstructed frequency-domain channel response. In response to each of the error signals satisfying the criterion, motion of an object in a space is detected based on the set of frequency-domain channel responses.

The embodiments provide a cryptography key for two communicating devices that is based on information known only to the devices. Each of the communicating devices determines the information without communicating key information related to the encryption key with the other. Each device receives a setup signal sent by the other device. Each device samples the received signal, generates sampling results, creates a plurality of keys based on the sampling results, selects a key of the plurality of keys based on criteria, and utilizes the selected key. The sets of plurality of keys may be created by creating each of the keys based on a different power threshold applied to the sampling results. The sets of plurality of keys may also be created by inputting the sampling results into each of a plurality of decoders to generate a key at each decoder that comprises a key of the plurality of keys.

The disclosure relates to a method performed in a network node for transmitting data in a wireless network. The network node is configurable for controlling a multiple input multiple output antenna system. The method comprises beamforming user specific data streams to one or more communication devices, UE.sub.1, . . . , UE.sub.K, wherein the beamforming is based on respective channel information available for each of the one or more communication devices, UE.sub.1, . . . , UE.sub.K, precoding control information streams using a transmit diversity scheme; and transmitting the beamformed user specific data streams and the precoded control information streams in a same transmission resource. The disclosure relates to a network node, method in communication device, communication device and computer programs and computer program products.

Embodiments relate to apparatuses (10; 20), methods and computer programs for determining transmission control information. The Apparatus (10) is suitable for a base band unit (110) of a base station transceiver (100) of a mobile communication system (300), the base station transceiver (100) further comprising one or more radio units (120) configured to wirelessly communicate with the base band unit (110) using one or more wireless fronthaul links. The apparatus (10) comprises at least one output (12) configured to transmit a downlink component of the one or more wireless fronthaul links to the one or more radio units (120). The apparatus (10) further comprises at least one input (14) configured to receive an uplink component of the one or more wireless fronthaul links from the one or more radio units (120). The apparatus (10) further comprises a control module (16) configured to control the at least one output (12) and the at least one input (14). The control module (16) is further configured to transmit a reference signal via the at least one output (12) to the one or more radio units (120). The control module (16) is further configured to receive a loopback version of the reference signal via the at least one input (14) from the one or more radio units (120). The control module (16) is further configured to determine transmission control information based on an attenuation of the reference signal determined based on the loopback version of the reference signal. The transmission control information comprises information related to a per-radio unit transmission power to be used by the one or more radio units (120) for transmissions on the one or more wireless fronthaul links. The control module (16) is further configured to provide the transmission control information to the one or more radio units (120) via the at least one output (12).

This disclosure relates to techniques for performing secure ranging wireless communication. A first wireless device may receive a ranging packet from a second wireless device in a wireless manner. The ranging packet may include a first random sequence portion and a second random sequence portion. The first wireless device may perform one or more channel and noise estimations for the ranging packet. The first wireless device may perform one or more security checks for the ranging packet based on any or all of the first random sequence portion, the second random sequence portion, or the channel and noise estimation(s).