A circuit for processing an N-level pulse amplitude modulation (PAM-N) signal according to an embodiment of the present invention comprises: an input unit receiving an input signal; a main amplifier connected to the input unit to amplify the input signal with a first gain; and an output unit outputting an output signal of the main amplifier, and the circuit further comprises an auxiliary amplifier connected in parallel with the main amplifier between the input unit and the output unit to variably amplify at least a portion of the input signal and apply the signal to the output unit according to a linearity improvement control signal corresponding to the output signal.

The embodiments of disclosure disclose a method and device for multiuser superposition transmission and a method and device for demodulating multiuser information transmission. In the method, two bit information streams are respectively modulated into a first complex symbol sequence and a second complex symbol sequence; superposition processing on the first complex symbol sequence and the second complex symbol sequence is performed to generate a third complex symbol sequence, wherein the third complex symbol sequence has a Gray mapping attribute; and a sending signal is formed according to the third complex symbol sequence, and the sending signal is sent to multiple receivers.

The embodiments of disclosure disclose a method and device for multiuser superposition transmission and a method and device for demodulating multiuser information transmission. In the method, two bit information streams are respectively modulated into a first complex symbol sequence and a second complex symbol sequence; superposition processing on the first complex symbol sequence and the second complex symbol sequence is performed to generate a third complex symbol sequence, wherein the third complex symbol sequence has a Gray mapping attribute; and a sending signal is formed according to the third complex symbol sequence, and the sending signal is sent to multiple receivers.

A transmission apparatus for a wireless device, comprising: an antenna for receiving an original signal and for backscattering a modulated signal containing information from the wireless device; a variable impedance coupled to the antenna, the variable impedance having an impedance value; a delta-sigma modulator coupled to the variable impedance for modulating the impedance value, and thereby a backscattering coefficient for the antenna, in accordance with the information to generate the modulated signal; and, a decoder coupled to the delta-sigma modulator for generating the impedance value from the information.

A transmission apparatus for a wireless device, comprising: an antenna for receiving an original signal and for backscattering a modulated signal containing information from the wireless device; a variable impedance coupled to the antenna, the variable impedance having an impedance value; a delta-sigma modulator coupled to the variable impedance for modulating the impedance value, and thereby a backscattering coefficient for the antenna, in accordance with the information to generate the modulated signal; and, a decoder coupled to the delta-sigma modulator for generating the impedance value from the information.

A transmission apparatus that transmits a block signal that includes a plurality of data symbols, includes: a symbol generation unit that generates data symbols; a fixed-symbol arrangement unit that generates a block symbol by arranging data symbols and fixed symbols such that the fixed symbols are inserted at predetermined positions in a block signal; a time-frequency conversion unit that converts the block symbol to a frequency domain signal that includes N samples; an interpolation processing unit that performs interpolation processing on the frequency domain signal; and a CP insertion unit that generates the block signal by inserting a Cyclic Prefix into a signal that has undergone the interpolation processing.

An ultra-wideband radio frequency transmission system capable of receiving a first signal with discrete levels, and including: a voltage-controlled oscillator capable of supplying a first oscillating signal including an oscillating circuit powered by a power supply circuit comprising at least one first current source controlled by the first signal with discrete levels or a second signal with discrete levels obtained from the first signal with discrete levels; a mixer capable of receiving the first oscillating signal and of supplying a second oscillating signal equal to the first oscillating signal multiplied by a gain which depends on the first signal with discrete levels or on a third signal with discrete levels obtained from the first signal with discrete levels; and an antenna or an electromagnetic coupling device capable of transmitting a radio frequency signal based on the second oscillating signal.

An ultra-wideband radio frequency transmission system capable of receiving a first signal with discrete levels, and including: a voltage-controlled oscillator capable of supplying a first oscillating signal including an oscillating circuit powered by a power supply circuit comprising at least one first current source controlled by the first signal with discrete levels or a second signal with discrete levels obtained from the first signal with discrete levels; a mixer capable of receiving the first oscillating signal and of supplying a second oscillating signal equal to the first oscillating signal multiplied by a gain which depends on the first signal with discrete levels or on a third signal with discrete levels obtained from the first signal with discrete levels; and an antenna or an electromagnetic coupling device capable of transmitting a radio frequency signal based on the second oscillating signal.

A method for implementing controller area network (CAN) communications between a plurality of CAN nodes using a single radio frequency (RF) coax cable is provided. In an aspect, a hardware interface (e.g., an electronic circuit) may be coupled to each of the plurality of CAN nodes. The hardware interface may receive a CAN signal from a first CAN node. The hardware interface may convert the CAN signal to a single RF signal and transmit the RF signal to a second CAN node over the single RF coax cable. Moreover, the hardware interface may transmit a CAN feedback signal received over the RF coax cable to the first CAN node. In an aspect, the hardware interface may include an amplitude modulation (AM) modulator, an AM detector, and a bandpass filter.

Provided is a transmission method that improves data reception quality in radio transmission using a single-carrier scheme and/or a multi-carrier scheme. The transmission method includes: generating a plurality of first modulated signals s1(i) and second modulated signals s2(i) from transmission data, the plurality of first modulated signals s1(i) being signals generated using a QPSK modulation scheme, and the plurality of second modulated signals s2(i) being signals generated using 16QAM modulation; generating, from the plurality of first modulated signals s1(i) and the plurality of second modulated signals s2(i), a plurality of first signal-processed signals z1(i) and a plurality of second signal-processed signals z2(i) which satisfy a predetermined equation; and transmitting the plurality of first signal-processed signals z1(i) and the plurality of second signal-processed signals z2(i) using a plurality of antennas. A first signal-processed signal and a second signal-processed signal having identical symbol numbers are simultaneously transmitted at the same frequency.