Systems and methods are provided for reducing power consumption in a mobile device having a Internet Protocol (IP) multimedia subsystem (IMS) framework for supporting, e.g., Voice over Long Term Evolution (VoLTE), IP Voice over High Speed Packet Access (VoHSPA), and Rich Communication Suite (RCS) features. To support such functionality in a mobile device while reducing power consumption, a local Session Initiation Protocol (SIP) agent is implemented in, e.g., a wireless modem, of the mobile device to which SIP-related signaling can be redirected, and at which SIP-related processing can be performed when an application processor (AP) Of the mobile device is in sleep mode, thereby negating a need to wake up the AP to handle such functionality.