What is the difference between simplex, half-duplex, and full-duplex communication?

Simplex communication is unidirectional, data flows in one direction only (e.g., broadcast radio, TV). Half-duplex allows bidirectional communication but not simultaneously; one party transmits while the other receives (e.g., walkie-talkies, some Wi-Fi). Full-duplex enables simultaneous two-way communication using separate channels or frequencies (e.g., telephone, cellular networks). Full-duplex requires more resources but provides better user experience and higher throughput.