A receiver receives signals and noise over a frequency spectrum of a desired received signal. The desired received signal is spread using code division multiple access. The received signals and noise are demodulated to produce a demodulated signal. The demodulated signal is despread using a code uncorrelated with a code associated with the desired received signal. A power level of the despread demodulated signal is measured as an estimate of the noise level of the frequency spectrum.

Embodiments of the present invention provide a wireless communications method, user equipment, a base station and a system, and relate to the field of wireless communications. The method includes: acquiring a frequency domain spreading factor, a symbol-level spreading factor and a transmission time interval-level spreading factor; and performing frequency domain spreading, symbol-level spreading and transmission time interval-level spreading on first to-be-sent information respectively according to the acquired spreading factors and sending first spread information; or, despreading, according to the acquired spreading factors, second spread information sent by a base station.