Explain the O-RAN architecture and its advantages.

O-RAN (Open Radio Access Network) disaggregates and virtualizes the RAN with open interfaces. Architecture splits: RU (Radio Unit) handles RF functions; O-DU (Distributed Unit) handles real-time L1/L2; O-CU (Central Unit) handles non-real-time L2/L3. Open fronthaul (7.2x split) between RU and DU enables multi-vendor interoperability. RIC (RAN Intelligent Controller): Near-RT RIC (<10ms) hosts xApps for radio resource management. Non-RT RIC (>1s) hosts rApps for policy, ML model training. SMO (Service Management and Orchestration) manages the network. Advantages: Vendor diversity reduces lock-in and costs. Innovation through xApps/rApps ecosystem. Cloud-native deployment on COTS hardware. AI/ML integration for network optimization. Challenges: Performance of virtualized RAN, fronthaul bandwidth requirements, multi-vendor integration testing, and security of open interfaces.