Broadband Access Abstraction
About: "The Open Broadband-Broadband Access Abstraction (OB-BAA) is an open source project that specifies the Northbound Interfaces (NBI), Core Components and Southbound Adapter Interfaces (SAI) for functions associated with the access network devices (e.g., configuration, reporting, alarms)"
Links: home, github
Project Clearwater
About: "open source implementation of IMS (the IP Multimedia Subsystem)"
Links: home
OpenAirInterface
About: "non-profit consortium to develop ecosystem for open source software/hardware development for the core network (EPC) and access-network (EUTRAN) of 3GPP cellular networks"
Links: home
OpenEPC
OpenIMSCore