A transmitter including a transmit section and a frame formatter. The transmit section is to generate a stream of data to be transmitted using a plurality of antennas and separate the stream of data into a plurality of substreams corresponding to respective ones of the plurality of antennas. The frame formatter is to form respective frames of data from the plurality of substreams. Each of the frames of data includes a short preamble including short training symbols, a long preamble including long training symbols, and a signal field indicating a quantity of the plurality of antennas. The transmit section is further to transmit the frames of data using respective ones of the plurality of antennas.

A diversity transmission method, a terminal, and a network-side device are provided. The diversity transmission method includes: determining, by a terminal, a target encoded codeword; and performing, by the terminal, diversity transmission based on the target encoded codeword, where the target encoded codeword meets a target encoding structure; the target encoded codeword is an encoding matrix with NN dimensions; N=2.sup.k, and k is a positive integer; the target encoding structure includes a first basic element, a second basic element, a first generation element, and a second generation element; the first generation element is an opposite number of a conjugate operation result of the first basic element, and the second generation element is a conjugate operation result of the second basic element; and the first basic element, the second basic element, the first generation element, and the second generation element are complex numbers or block matrices.