According to one aspect of the present invention, a multi-antenna transmitter is provided. The transmitter includes: a data block acquiring device for acquiring multiple data streams, wherein each data stream includes data blocks at multiple slots; and a grouping and mapping device for grouping and mapping each data block, wherein the data blocks at the same slot in each data stream are grouped according to the number of the antennas and each group is mapped to one of the antennas respectively, and the different data blocks in the same group are mapped to different sub-bands respectively; and wherein grouping and mapping manners which are not exactly the same are adopted for the data blocks at different slots, and the grouping and mapping manners include data block grouping manners, group-to-antenna mapping manners, and sub-band mapping manners. And the groups of data blocks at the multiple slots are transmitted via the antennas. With the technical solutions of the present invention, a reduced PAPR during data transmission can be achieved while the diversity gain is guaranteed.