After three decades of fragmentation within the mobile communication industry-with each technology generation offered by two or more competing solutions-the next generation currently being deployed around the globe is the first to be built with a common technology offering the potential of true global mobility. This next Long Term Evolution (LTE) technology is based on the twin foundations of Orthogonal Frequency Division Multiple Access (OFDMA) 1 and multiple input multiple output (MIMO) 2 and has been jointly optimized to support both time and frequency division duplexing. While originally targeted as a large "macro" cell technology for deployment at existing and new cell sites, recent advances in standards and enabling technologies have allowed the mobile industry to apply the same LTE technology to offer wireless access from small cell nodes, known as femtocells and metro cells and to non-civilian usage for public safety and railway applications. In addition, new MIMO modes supporting up to eight antennas, a broadcast service known as evolved Multimedia Broadcast Multicast Service (eMBMS) and refinements to mobility mechanisms between LTE and legacy second generation (2G) and third generation (3G) radio access technologies have been added to the base standards incorporated within 3 GPP Release 8, the first that offered the LTE access technology.
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