  We introduce DBS, a new technique for user selection in downlink multi-user
communications with extra-large (XL) antenna arrays. DBS categorizes users
according to their equivalent distance to the antenna array. Such
categorization effectively accounts for inter-user interference while largely
reducing the computational burden. Results show that (i) DBS achieves the same
performance as the reference zero-forcing beamforming scheme with a lower
complexity; (ii) a simplified version of DBS achieves a similar performance
when realistic spherical-wavefront (SW) propagation features are considered;
(iii) SW propagation brings additional degrees of freedom, which allows for
increasing the number of served users.
