A system filters out-of-band radio frequency emissions generated by wireless transmission of a first signal by a first transmitter from a wireless transmission of a second transmitter. The first signal is communicated from the first transmitter to the second transmitter via one or more wired connections. An out-of-band portion of a modulated format of the first signal is inverted to generate an inverted out-of-band component signal. The inverted out-of-band component signal is combined with a second signal of the second transmitter to create a filtering second signal. The filtering second signal is wirelessly transmitted from the second transmitter concurrently with wireless transmission of the first signal by the first transmitter, wherein the wireless transmission of the inverted out-of-band component signal in the filtering second signal by the second transmitter is synchronized with the wireless transmission of the first signal by the first transmitter.

Embodiments of this application disclose a data transmission method, apparatus, and system in backscatter communication, to improve spectrum usage efficiency of data. An embodiment of this application provides a data transmission method in backscatter communication, including: generating a first frame, where the first frame carries first data and second data, the first data and the second data in the first frame use different modulation schemes, the first data is sent to a first tag, and the second data is sent to a second tag; and sending the first frame to the first tag and the second tag.

Embodiments of this application disclose a data transmission method, apparatus, and system in backscatter communication, to improve spectrum usage efficiency of data. An embodiment of this application provides a data transmission method in backscatter communication, including: generating a first frame, where the first frame carries first data and second data, the first data and the second data in the first frame use different modulation schemes, the first data is sent to a first tag, and the second data is sent to a second tag; and sending the first frame to the first tag and the second tag.

A method of encoding video data comprising: generating coefficients based on digital sample values of the video data; determining a spectral efficiency for a channel; determining a value n based on the spectral efficiency of the channel; generating coefficient vectors, wherein each of the coefficient vectors includes n of the coefficients; determining an amplitude value for a coefficient vector based on a mapping pattern, wherein for each respective allowed coefficient vector in a plurality of allowed coefficient vectors: the mapping pattern maps the respective allowed coefficient vector to a respective amplitude value in a plurality of amplitude values, and the respective amplitude value is adjacent in an n-dimensional space to at least one other amplitude value in the plurality of amplitude values that is adjacent to the respective amplitude value in a monotonic number line of the amplitude values, and modulating an analog signal based on the amplitude values.

A method of encoding video data comprising: generating coefficients based on digital sample values of the video data; determining a spectral efficiency for a channel; determining a value n based on the spectral efficiency of the channel; generating coefficient vectors, wherein each of the coefficient vectors includes n of the coefficients; determining an amplitude value for a coefficient vector based on a mapping pattern, wherein for each respective allowed coefficient vector in a plurality of allowed coefficient vectors: the mapping pattern maps the respective allowed coefficient vector to a respective amplitude value in a plurality of amplitude values, and the respective amplitude value is adjacent in an n-dimensional space to at least one other amplitude value in the plurality of amplitude values that is adjacent to the respective amplitude value in a monotonic number line of the amplitude values, and modulating an analog signal based on the amplitude values.

Introduced are a data transmission method, apparatus and device based on a modulation signal and a storage medium. The method includes steps as follows: calculating a first amplitude-modulated sine wave signal and a second amplitude-modulated sine wave signal with each preset frequency individually; based on the first amplitude-modulated sine wave signal and the second amplitude-modulated sine wave signal with the each preset frequency and according to a preset mapping rule, mapping a sequence of data bits to be sent into a signal sequence; and processing the signal sequence to generate a transmittable radio-frequency signal, and sending the transmittable radio-frequency signal to a receiving end.

Introduced are a data transmission method, apparatus and device based on a modulation signal and a storage medium. The method includes steps as follows: calculating a first amplitude-modulated sine wave signal and a second amplitude-modulated sine wave signal with each preset frequency individually; based on the first amplitude-modulated sine wave signal and the second amplitude-modulated sine wave signal with the each preset frequency and according to a preset mapping rule, mapping a sequence of data bits to be sent into a signal sequence; and processing the signal sequence to generate a transmittable radio-frequency signal, and sending the transmittable radio-frequency signal to a receiving end.

A contactless communication method comprises retro-modulation of a carrier signal received at the terminals of an antenna in an alternation of modulated states and unmodulated states. The modulated state comprises a modulation of a load at the terminals of the antenna at zero impedance, and the transitions from the modulated state to the unmodulated state are controlled at an instant determined by a first delay.

A contactless communication method comprises retro-modulation of a carrier signal received at the terminals of an antenna in an alternation of modulated states and unmodulated states. The modulated state comprises a modulation of a load at the terminals of the antenna at zero impedance, and the transitions from the modulated state to the unmodulated state are controlled at an instant determined by a first delay.

An apparatus of a transmitter and method are provided, the apparatus comprising a processor that calculates a supply voltage (SV) value (SVV) to provide as an SV for a power amplifier (PA) of the transmitter for transmissions during a transmission time slot (TS). When the SV<an envelope tracking (ET) threshold (ETT), then the processor configures the PA to transmit a signal in an average power tracking (APT) mode that maintains the SV at the SVV during the TS. When the SV≥ETT, and an APT condition is met, then the processor configures the PA to transmit the signal in the APT mode. When the SV≥ETT, and the APT condition is not met, then the processor transmits by an adjustment to the SVV to track an amplitude modulation envelope during the TS in an ET mode.