1. A terminal access method, comprising:determining, by a terminal, to enter a contention-based access phase;
determining, by the terminal during each transmission of binary data, a first signature according to a random number seed and a signature matrix; and
mapping, by the terminal, according to the first signature, the binary data to a multi-dimensional symbol for transmission, wherein first signatures used during different transmissions of binary data are different; and
generating, by the terminal, a random number according to the random number seed, randomly selecting a plurality of second signatures from the signature matrix according to the random number, and combining the plurality of second signatures into the first signature.