  Near-field (NF) communications draw much attention in the context of
extremely large-scale antenna arrays (ELAA). Owing to a large number of
antennas and high carrier frequency, the NF coverage distance is quite
substantial, where the electromagnetic radiation propagates by spherical waves,
in contrast to the conventional planar waves of the far-field. Motivated by
these facts, the block-dominant compressed sensing (BD-CS) assisted NF
communications are proposed. Specifically, we elucidate why block sparsity
exists in the distance-limited NF region. Then, block-dominant side-information
(BD-SI) is introduced in support of the actual NF communication implementation.
We validate that BD-CS is capable of providing exceptional channel estimation
accuracy and high spectral efficiency, where the associated challenges,
opportunities and its actual implementation in NF communications need to be
carefully addressed.
