A wireless power transmission apparatus includes: a transmitter that wirelessly transmits electric power; and a receiver that can receive, in a resonant relation with the transmitter, a transmission signal including the electric power transmitted from the transmitter, wherein the receiver includes a frequency variable unit that can change a reception resonant frequency; a detecting unit that detects reception power; and a control unit that controls the frequency variable unit to perform frequency adjustment such that the reception power detected by the detecting unit is maximized.

A wireless power transmission apparatus includes: a transmitter that wirelessly transmits electric power; and a receiver that can receive, in a resonant relation with the transmitter, a transmission signal including the electric power transmitted from the transmitter, wherein the receiver includes a frequency variable unit that can change a reception resonant frequency; a detecting unit that detects reception power; and a control unit that controls the frequency variable unit to perform frequency adjustment such that the reception power detected by the detecting unit is maximized.

Disclosed is a blind authentication method for a frequency selective fading channel based on belief propagation. The method includes: transmitting carrier signals to a frequency selective fading channel with a plurality of paths, where each of the carrier signals includes an authentication signal, a pilot signal and an information signal, and the authentication signal is superimposed on the pilot signal; receiving the carrier signals, performing blind known interference cancellation (BKIC) processing on a carrier signal in each of the plurality of paths of the frequency selective fading channel to obtain a target signal, and performing differential signal processing on the target signal to obtain a target authentication signal, where in the BKIC processing, a pilot signal in the each of the plurality of paths is cancelled through a belief propagation technique by using a prior probability density function and a Tanner graph of the target signal; obtaining a reference signal based on a key and the pilot signal in the each of the plurality of paths, performing the differential signal processing on the reference signal to obtain a reference authentication signal, and calculating a correlation between the target authentication signal and the reference authentication signal to obtain a test statistic; and comparing the test statistic with a prescribed threshold to determine whether the carrier signal in the each of the plurality of paths can pass authentication.

A phase shifter (60) is provided corresponding to an antenna element constituting an array antenna and is configured to change a phase of a radio frequency signal to be transmitted or received by a corresponding antenna element. The phase shifter (60) includes a first distributor (61) configured to distribute the radio frequency signal input thereto into a plurality of first distributed signals having mutually different phases; second distributors (62) provided corresponding to the first distributed signals, the second distributors each being configured to distribute a corresponding one of the first distributed signals into a plurality of second distributed signals having mutually different amplitudes; a controller (63) configured to control on/off of the second distributed signals; and a combiner (64) configured to combine the second distributed signals that are controlled on by the controller (63).

A system and method for transmitting data ultrasonically through biological tissue employs a network of a plurality of nodes, at least a portion of the nodes implantable within the biological tissue. At least one implanted node includes a transmitter having an orthogonal frequency division multiplex signal generator to encode an ultrasonic signal for transmission through the biological tissue to an ultrasonic receiver at another node.

Methods and apparatus that enable one or more wireless networks to minimize inter-cellular interference (ICI) at a receiver. In one embodiment, the network comprises an OFDM-based cellular network, and the method comprises utilizing a priori knowledge of non-data portions of signals from multiple base stations in order to schedule transmissions. In one variant, these non-data portions comprise pilot tones; the pilot tones can be scheduled onto various time-frequency resources of the network so as to minimize ICI. The mobility context of the receiver can also be used as a basis for dynamically adjusting the pilot tone density. In another variant, precoding (e.g., Tomlinson-Harashima precoding) can be applied to shape the non-data portions of the transmitted signals so as to mitigate ICI. In yet other variants, frame preambles and learning sequences are used as the basis for invoking selective transmission time shifts across the potentially interfering base stations so as to minimize ICI.

A broadcast signal receiver is disclosed. A broadcast signal receiver according to an embodiment of the present invention comprises a synchronization & demodulation module performing signal detection and OFDM demodulation on a received broadcast signal; a frame parsing & deinterleaving module performing parsing and deinterleaving of a signal frame of the broadcast signal; a demapping & decoding module performing conversion of data of at least one Physical Layer Pipe (PLP) of the broadcast signal into the bit domain and FEC decoding of the converted PLP data; and an output processing module outputting a data stream by receiving the at least one PLP data.

Embodiments of the present invention disclose a reference signal transmission method. A transmitting apparatus multiplies M first symbol sequences by M coefficients respectively to obtain M second symbol sequences, where M is a positive integer greater than 1, the symbol sequence includes L symbols, L is a positive integer greater than 1, and the M coefficients each have a magnitude of 1. The transmitting apparatus maps the M second symbol sequences onto a first time-frequency resource to obtain a frequency domain signal. The transmitting apparatus performs an IFFT operation on the frequency domain signal to obtain a time domain signal. And the transmitting apparatus sends the time domain signal.

A communication system includes a repetitive orthogonal frequency-division multiplexing (ROFDM) transmitter communicating with an ROFDM receiver. The ROFDM transmitter includes an ROFDM modulator, which includes a K-point Fast Fourier Transform receiving a block of time-domain data symbols and generating an initial orthogonal frequency-division multiplexing symbol. The initial orthogonal frequency-division multiplexing symbol is based on a block of frequency-domain data symbols corresponding to the block of time-domain data symbols. The initial orthogonal frequency-division multiplexing symbol includes an ending part. The ROFDM modulator includes an orthogonal frequency-division multiplexing symbol repeater generating a repetitive orthogonal frequency-division multiplexing symbol by repeatedly reproducing the initial orthogonal frequency-division multiplexing symbol. The modulator includes a cyclic prefix adder prepending a cyclic prefix to the repetitive orthogonal frequency-division multiplexing symbol to generate a baseband transmitted signal. The cyclic prefix includes the ending part of the initial orthogonal frequency-division multiplexing symbol. The ROFDM receiver includes an ROFDM demodulator.

Methods, systems, and devices for wireless communication are described. A base station may communicate with a user equipment (UE) using frequency resources (e.g., subcarriers) with scalable channel spacing and time resources (e.g., slots) with variable slot durations. The individual slots may include multiple symbols, and each symbol may be allocated for communication in a specific link direction (e.g., uplink, downlink, or sidelink). For UEs configured to operate in a half-duplex mode, the base station may allocate sufficient time for the UE to transition between uplink and downlink configurations. In other cases, for carrier aggregation, the base station may coordinate with the UE to prevent conflicting communications (e.g., simultaneous uplink and downlink transmissions). UEs or other devices may communicate directly with one another in a device-to-device configuration using the same or a similar scheme to allow for half-duplex devices to transition between sending and receiving.