Method and apparatus are provided for estimating first downlink (DL) channel information of first DL channels in accordance with reference signals received on first uplink (UL) channels, the first UL channels being a subset of available UL channels, and the first DL channels corresponding to the first UL channels. Channel feedback is received for a set of DL channels, and second DL channel information is estimated in accordance with the estimated first DL channel information and the received channel feedback.

A method includes transmitting, by a transceiver configured to concurrently transmit over multiple transmit paths and receive over multiple receive paths, one or more signals, the transceiver comprising multiple transmit antennas and multiple receive antennas. The method also includes, for at least one of the multiple receive antennas: applying a transmit path model to one or more transmitted signals to generate one or more transmit path estimates, the transmit path model determined based on multiple analog power amplifiers associated with the multiple transmit paths; calculating one or more estimated self-interference (SI) signals based on the one or more transmit path estimates using an equalizer array comprising a predetermined channel model; and subtracting the one or more estimated SI signals from one or more receive signals received at the at least one receive antenna to obtain one or more residual signals.

An apparatus is provided for using a square wave digital chirp signal for optical chirp range detection. A laser source emits an optical signal and a RF waveform generator generates an input digital chirp signal based on the square wave digital chirp signal. A frequency of the optical signal is modulated based on the input digital chirp signal. A splitter divides the optical signal into a transmit optical signal and a reference optical signal. A detector combines the reference optical signal and a return optical signal from an object. The detector generates an electrical output signal based on the combined reference optical signal and the return optical signal. A processor determines a range to the object based on a characteristic of a Fourier transform the electrical output signal. A method is also provided for using the square wave digital chirp signal for optical chirp range detection.

Wireless communications systems and methods related to wireless communications in a system are provided. A user equipment (UE) may receive from a base station (BS), an uplink (UL) scheduling grant indicating subband precoding information and a resource allocation spanning a plurality of subbands. The UE may determine a plurality of subband precoders based on the subband precoding information. Each precoder of the plurality of subband precoders may be associated with a subband of the plurality of subbands. The UE may transmit to the BS, an UL communication signal in the resource allocation using the plurality of subband precoders.

A method for calibrating a communication channel coupling first and second components includes transmitting a data signal from the first component to the second component on the communication channel, and sensing a characteristic, such as phase, of the data signal on the second component. Information about the sensed characteristic is fed back to the first component using an auxiliary channel. An adjustable parameter, such as phase, for the transmitter is adjusted on the first component in response to the information. Also, a characteristic of a data signal received from the transmitter on the second component is sensed and used to adjust an adjustable parameter for the receiver on the first component.

A signaling system includes a pre-emphasizing transmitter and an equalizing receiver coupled to one another via a high-speed signal path. The receiver measures the quality of data conveyed from the transmitter. A controller uses this information and other information to adaptively establish appropriate transmit pre-emphasis and receive equalization settings, e.g. to select the lowest power setting for which the signaling system provides some minimum communication bandwidth without exceeding a desired bit-error rate.

A base station includes a transmit path circuitry to transmit an indication of whether a subscriber station is configured with precoding matrix indicator/rank indicator (PMI/RI) reporting. The transmit path circuitry sets a pre-coding granularity to multiple physical resource blocks in the frequency domain to perform a same pre-coding over a bundled resource block if the subscriber station is configured with PMI/RI reporting. The bundled resource block includes multiple consecutive physical resource blocks in the frequency domain. The base station also includes a receive path circuitry to receive feedback from the subscriber station.

The present disclosure discloses a signal sending method and device. The method includes: receiving, by a base station, an uplink pilot signal sent by authorized user equipment, and determining a direction vector parameter and a first channel fading parameter of a channel calculating, according to the direction vector parameter and the first channel fading parameter, a first signal beamformer parameter, determining a transmission area of an artificial noise signal according to the direction vector parameter, and calculating a second signal beamformer parameter; and processing a to-be-transmitted signal by using the first signal beamformer parameter and the second signal beamformer parameter, and transmitting the processed signal. In this way, in a non-target direction, energy leakage of the secrecy signal to the authorized user equipment is relatively small, and transmitted artificial noise signals are concentrated in an area with a relatively high secrecy signal leakage risk.

A communication system includes: a transmission device including a transmission data generator, a pattern generator, a transmitter, and a control signal receiver, the transmission data generator that is configured to generate transmission data, the pattern generator that is configured to generate an alternate pattern alternating at every lapse of a predetermined time, the transmitter that includes a first equalization circuit and is configured to transmit a transmission signal including the transmission data and the alternate pattern, the first equalization circuit that is configured to adjust equalization characteristics on the basis of first instruction information, and the control signal receiver that is configured to receive the first instruction information; and a reception device including a receiver, a first detector, and a control signal transmitter, the receiver that is configured to receive the transmission signal, the first detector that is configured to detect a frequency component corresponding to the predetermined time of the alternate pattern included in the transmission signal, and the control signal transmitter that is configured to generate the first instruction information on the basis of a result of detection by the first detector and is configured to transmit the first instruction information.

A signal pre-compensation method is provided. In the method, at least one target frequency subband is determined from a plurality of frequency subbands of a first optical signal and an optical signal of the at least one target frequency subband in the first optical signal is demodulated based on the at least one target frequency subband. A first electrical signal is obtained after demodulation, and a pre-compensation parameter is updated based on the at least one target frequency subband, the first electrical signal, and a second electrical signal. Herein the pre-compensation parameter is used to perform signal pre-compensation on the second electrical signal, and the first optical signal is generated after the pre-compensation is performed on the second electrical signal.