Abstract
The invention discloses a beam alignment method of an antenna array, a multi-beam transmission system and a multi-beam transmission device. The method comprises the following steps that a base station adopts a plurality of groups of multi-peak beam patterns as beam patterns for transmitting a plurality of synchronization signals; user equipment scans the synchronization signal, judges the synchronization signal with the strongest receiving power and the corresponding receiving beam direction, and transmits an initial access message comprising index information of the strongest synchronization signal (explicit or implicit) through a random access channel; the base station receives an initial access message on a random access channel by adopting a plurality of groups of single-peak beam patterns, and judges the single-peak beam pattern with the strongest receiving power of the initial access message so as to compare the single-peak beam pattern with a main beam of the multi-peak beam pattern corresponding to index information of a synchronization signal with the strongest receiving power in the initial access message, so as to determine the optimal beam direction transmitted to the user equipment.