4G systems represent a collection of wireless standards that are all adapted to be 100% packet and IP based. They will be a complete replacement for current networks and will provide a comprehensive and secure IP solution where voice, data, and streamed multimedia can be given to users on an "anytime, anywhere" basis. 4G networks are designed to give subscribers access to much richer content on their phones, including IPTV, streaming audio and video, digital video broadcast, and video chat, at much higher data rates than previous generations. 4G promises
higher network capacity and more simultaneous users per cell. (Download and upload: 15-30Mbps) Technologies directly related to 4G are WiMax, LTE, and Clear wire.
WiMax
WiMax is an IP network designed to move data instead of voice communication. It could replace mobile technologies such as GSM and CDMA or simply can be added to networks with GSM and DSMA to increase their capacity. The WiMAX Forum was formed in June 2001 to promote conformity and interoperability of the standard, called WiMAX. The group describes WiMAX as "a standards-based technology enabling the delivery of last mile wireless broadband access as an alternative to cable and DSL."
Questions still surround the viability of WiMax technology. Sprint and Clearwire are the only large service providers that have committed to using WiMax for mobile technology. Most other service providers that have embraced WiMax are using it as a fixed wireless technology. The WiMax forum anticipates that the WiMax mobile networks will focus less on service to mobile phones and more on service to other wireless Web-enabled devices.
LTE
Long-Term Evolution (LTE) it is an IP data network that optimizes the transmission of data (rather than voice) packets. It is expected to be deployed in 2010, but it competes with WiMax as the 4G standard of choice for network operators. AT&T and Verizon Wireless in the United States and many European carriers have already said they plan to use LTE instead of WiMax because it appears to be more efficient. LTE promises to bring high-speed data access not only to mobile phones, but also to HD TVs, LTE-enabled music players, and much more. Some people believe that WiMax technology will be subsumed into LTE, but that debate is still being played out.
Clearwire
Clearwire is a brand-name wireless Internet service provider (ISP) that operates in the United States, Ireland, Belgium, Spain, Denmark, and Mexico. It provides a unique wireless network that uses WiMax technology with 3G technology to provide 4G wireless network access. Clearwire launched in the United States in 2008, but its goal is to provide nationwide 4G network connections in the future. The company has been testing many different high-speed mobile technologies but has been criticized because it has not adopted the WiMax technology.
