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UMB (Ultra Mobile Broadband) was the brand name for a project within 3GPP2 to improve the CDMA2000 mobile phone standard for next generation applications and requirements. In November 2008, Qualcomm, UMB's lead sponsor, announced it was ending development of the technology, favoring LTE instead.〔(Qualcomm halts UMB project ), Reuters, November 13th, 2008〕 Like LTE, the UMB system was to be based upon Internet (TCP/IP) networking technologies running over a next generation radio system, with peak rates of up to 280 Mbit/s. Its designers intended for the system to be more efficient and capable of providing more services than the technologies it was intended to replace. To provide compatibility with the systems it was intended to replace, UMB was to support handoffs with other technologies including existing CDMA2000 1X and 1xEV-DO systems. However 3GPP added this functionality to LTE, allowing LTE to become the single upgrade path for all wireless networks. No carrier had announced plans to adopt UMB, and most CDMA carriers in Australia, USA, Canada, China, Japan and South Korea have already announced plans to adopt either WiMAX or LTE as their 4G technology. == Summary == *OFDMA-based air interface *Frequency Division Duplex *Scalable bandwidth between 1.25–20 MHz (OFDMA systems are especially well suited for wider bandwidths larger than 5 MHz) *Supports mixed cell sizes, e.g., macro-cellular, micro-cellular & pico-cellular. *IP network architecture *Supports flat, centralized and mixed topologies *Data speeds over 275 Mbit/s downstream and over 75 Mbit/s upstream 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Ultra Mobile Broadband」の詳細全文を読む スポンサード リンク
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