Enhancing Channel Estimation and Efficiency in Millimeter-Wave Massive Multiple Input Multiple Output Systems by Exploiting Reconfigurable Intelligent Surface and Gegenbauer Graph Neural Networks for High-Resolution Signal Reconstruction. - T. D. Subash; T. D. Subha; Janaki Manohar N; Alwin Vinifred Christopher (Int. J. Commun. Syst., 2025)