In FIG. 8 and FIG. 9, the mapping manner to 8 discrete subcarriers shown in Type 1 can achieve an effect of the mapping to 8 contiguous subcarriers shown in Type 2. The size of a subcarrier corresponding to a preamble signal symbol in Type 2 is equal to the size of a subcarrier corresponding to 4 preamble signal symbols in Type 1, and the length of the preamble signal symbol in Type 1 is equal to the length of the 4 preamble signal symbols in Type 2. When the same preamble signal is mapped to M contiguous subcarriers on the 4 preamble signal symbols in Type 2, its effect can be achieved same as that of which the preamble signal is mapped to M discrete subcarriers on one preamble signal symbol of Type 1.
In addition, FIG. 8 and FIG. 9 only schematically show a size of the first bandwidth to which the preamble signal is mapped. In practice, the number of subcarriers included in the first bandwidth depends on actual situations.
Alternatively, when a type of sequence of the preamble signal includes multiple candidate sequences, the multiple candidate sequences may be mutually orthogonal.
Alternatively, the sequence of the preamble signal may be a primary synchronization signal (PSS) sequence and/or a secondary synchronization signal (SSS) sequence. Thus, the PSS sequence and/or the SSS sequence can be reused.
