A library of reference signal ports, a library of reuse factor identifications (ID) for Non-Orthogonal Multiple Access (NOMA), and a library of time-frequency resources broadcast by a base station (BS) can be received by user equipment (UE). A time-frequency resource in the library of time-frequency resources, a reuse factor ID in the library of reuse factor IDs, and a reference signal port in the library of reference signal ports can be selected. An initial sequence acquired by scrambling uplink data to be transmitted to the BS on the time-frequency resource is determined according to at least one of the reuse factor ID selected or the reference signal port selected, as well as a first numbering corresponding to a cell where the UE camps.