4G is the short term for fourth-generation wireless, the stage of broadband mobile communications that will supersede the third generation (3G). While neither standards bodies nor carriers have concretely defined or agreed upon what exactly 4G will be, it is expected that end-to-end IP and high-quality streaming video will be among 4G's distinguishing features. Fourth generation networks are likely to use a combination of WiMAX and WiFi.

Technologies employed by 4G may include SDR (Software-defined radio) receivers, OFDM (Orthogonal Frequency Division Multiplexing), OFDMA (Orthogonal Frequency Division Multiple Access), MIMO (multiple input/multiple output) technologies, UMTS and TD-SCDMA. All of these delivery methods are typified by high rates of data transmission and packet-switched transmission protocols. 3G technologies, by contrast, are a mix of packet and circuit-switched networks.

When fully implemented, 4G is expected to enable pervasive computing, in which simultaneous connections to multiple high-speed networks provide seamless handoffs throughout a geographical area. Network operators may employ technologies such as cognitive radio and wireless mesh networks to ensure connectivity and efficiently distribute both network traffic and spectrum.

The high speeds offered by 4G will create new markets and opportunities for both traditional and startup telecommunications companies. 4G networks, when coupled with cellular phones equipped with higher quality digital cameras and even HD capabilities, will enable vlogs to go mobile, as has already occurred with text-based moblogs. New models for collaborative citizen journalism are likely to emerge as well in areas with 4G connectivity.

A Japanese company, NTT DoCoMo, is testing 4G communication at 100 Mbps for mobile users and up to 1 Gbps while stationary. NTT DoCoMo plans on releasing their first commercial network in 2010. Other telecommunications companies, however, are moving into the area even faster.  Sprint Nextel has announced a 4G broadband mobile network nationwide using WiMAX.

4G technologies are sometimes referred to by the acronym "MAGIC," which stands for Mobile multimedia, Anytime/any-where, Global mobility support, Integrated wireless and Customized personal service.