4G is the short name for the fourth-generation wireless, the stage of broadband mobile communications that the third generation (3G) will replace.
Carriers that use orthogonal frequency-division multiplexing (OFDM) instead of Time Division Multiple Access (TDMA) or Code Division Multiple Access (CDMA) are increasingly marketing their services as 4G, even when their data speeds are not as obvious the International Telecommunication Union (ITU) specifies. The ITU is a 4G network, a mobile device that is capable of exchanging data at 100 Mbps. A 3G network, on the other hand, can offer data speeds as slow as 3.84 Mbps.
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Although the carrier still disagree about how a 4G network build by using data Long Term Evolution (LTE), or country correlation for Microwave Access, WiMAX, all companies seem to agree agree that OFDM is one of the key indicators that the service can legally be sold as 4G. OFDM is a kind of digital modulation where the signal is split into several narrowband channels at different frequencies. It is more efficient than TDMA, which divides channels into the space of time and multiple users in turn the transfer queue, or CDMA, which transmits multiple signals simultaneously on the same channel.
Fully implemented, 4G is expected to pervasive computing in which simultaneous connections to multiple high-speed networks provide seamless handoffs throughout a geographical area. Coverage of emerging technologies such as femtocells and Pico Cell developed to meet the needs of mobile users in homes, public buildings and institutions to meet, thus freeing network resources for mobile users roaming or remote areas of the country.