4G wireless is a packet switched wireless system designed to provide high throughput and wide area coverage. It uses technologies like OFDM and UWB to achieve data rates of 20Mbps and support mobile speeds up to 200km/hr. 4G aims to replace current mobile networks with a single worldwide standard based on IP to provide uniform multimedia services across heterogeneous access technologies. Key applications of 4G include interactive multimedia, streaming video, traffic control systems, and public safety communications.