This thesis focuses on the innovative design and implementation of communication capabilities integrated into an existing Phase-Modulated Continuous-Wave (PMCW) radar system for automotive applications. The project addresses the critical need for radar-communication co-existence, offering a solution that enables simultaneous high-resolution radar sensing and real-time data transmission with the same hardware. The key contribution of this work is the development of a system prototype that allows radar and communication functionalities to operate concurrently, without compromising radar performance. Among the various innovations introduced, the most challenging are proper waveform design, advanced software algorithms for Carrier Frequency Offset (CFO) compensation and phase recovery, and real-time radar and communication processes management.