This deliverable introduces the initial version of the MultiX Perception System (MPS), a key enabler for Integrated Sensing and Communications (ISAC) within heterogeneous Radio Access Network (RAN) environments. The MPS integrates sensing capabilities across diverse technologies—including 3rd Generation PartnershipProject (3GPP) components (RU, DU, CU), User Equipment, and non-cellular systems such as Wi-Fi—to form a unified, scalable perception framework. Central to the architecture is the Measurement Sensing Processing Function (m-SePF), which collects, processes, and fuses sensing data to provide accurate, robust perceptionservices.