  Extremely large antenna arrays (ELAAs) can provide higher spectral
efficiency. However, the use of narrower beams for data transmission
significantly increases the overhead associated with beam training. In this
letter, we propose a novel patterned beam training (PBT) scheme characterized
by its low overhead and complexity. This scheme requires only a single linear
operation by both the base station and the user equipment to determine the
optimal beam, reducing the training overhead to half or even less compared to
traditional exhaustive search methods. Furthermore, We discuss the pattern
design principles in detail and provide specific forms. Simulation results
demonstrate that the proposed scheme outperforms the compared methods in terms
of beam alignment accuracy and achieves a balance between signal-to-noise ratio
(SNR) conditions and training overhead, making it a promising alternative.
