Embodiments herein achieve a method and system for selecting non-coherent spreading sequences with binary alphabets {0, 1} with variable spreading factors. The method generates circular shift equivalent sets of spreading sequences by circularly shifting base sequences with elements {1, 0} and having at least one variable spreading factor. The method determines whether each spreading sequence in the circular shift equivalent set meets pre-defined spreading sequence criteria. The spreading sequence criteria comprise balanced criteria, a non- repetition criteria, non-circular criteria, and conjugate criteria. Furthermore, the method selects the spreading sequence from expansions of at least one spreading sequence from the circular shift equivalent sets in response to determining that the spreading sequences in the circular shift equivalent sets meets the pre-defined spreading sequence criteria.

The present invention is designed to reduce the decrease of spectral efficiency even when repetitious transmission is applied to communication by user terminals, in which the band to use is limited to a partial narrow band in a system band. According to one aspect of the present invention, a user terminal, in which the band to use is limited to partial narrow bands in a system band, has a receiving section that receives information related to spreading codes, a generation section that generates uplink signals, and a transmission section that repeats transmitting uplink signals in a plurality of subframes, and the generation section applies a predetermined spreading code to an uplink signal that is transmitted in part or all of the plurality of subframes, based on the information related to spreading codes.

A wireless transmitting method comprising: obtaining a first-spread-spectrum-signal (SS1-signal); producing a doubly-spread-spectrum-signal (SS2-signal) from the SS1-signal utilizing a spreading-sequence out of at least one spreading-sequence; modulating the SS2-signal to a Radio-Frequency SS2-signal (RF-SS2-signal); and transmitting the RF-SS2-signal.

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.