Provided are an information transmission method and apparatus, a terminal and a network device. The information transmission method comprises: transmitting, to a network device, uplink control information (UCI) carrying timing advance (TA) information.

Provided are a system and method of generating a wake up signal, the method including receiving plurality of input samples; performing subcarrier mapping that maps the plurality of input samples to a set of subcarriers, thereby generating a subcarrier mapper output; generating a first orthogonal frequency-division multiplexing (OFDM) signal by mapping at least a portion of the subcarrier mapper output to a first frequency band that corresponds to a first wake up signal symbol; generating a second OFDM signal by mapping at least a portion of the subcarrier mapper output to a second frequency band that corresponds to a second wake up signal symbol; and generating a wake up signal comprising at least a portion of the first OFDM signal to represent the first wake up symbol and at least a portion of second OFDM signal to represent the second wake up signal.

A digital to analog signal conversion system with a local oscillator, a control circuit, a radio-frequency digital to analog converter circuit, and a power combiner circuit is presented. The local oscillator generates a plurality of local oscillator phase signals. The control circuit receives a baseband in-phase (I) signal and a baseband quadrature (Q) signal and generates a plurality of control signals. The radio-frequency digital to analog converter circuit includes first and second pluralities of switch units that generate positive and negative radio-frequency signals respectively, based on the plurality of local oscillator phase signals and the plurality of control signals. The power combiner circuit generates a radio-frequency output signal based on a combination of the positive radio-frequency signal from the first plurality of switch units and the negative radio-frequency signal from the second plurality of switch units.