Low-Complexity Distance-Based Scheduling for Multi-User XL-MIMO Systems

We introduce Distance-Based Scheduling (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.