Reconfigurable Integrated Sensing and Communications (RISAC): Sparse MIMO and Hybrid Beamforming in Far and Near Fields

This article provides a comprehensive investigation into reconfigurable integrated sensing and communications (RISAC), an emerging paradigm designed to maximize the performance–cost tradeoff by exploiting the inherent spatial sparsity of multiple-input multiple-output (MIMO) arrays. Deviating from conventional static ISAC, RISAC adopts a cognitive “perception–action” cycle, enabling the adaptive reconfiguration of array geometries and beamforming weights in response to dynamic environmental feed