 at high data rates, which allows terminals at moderate distances from the base station to continue operating in high-capacity mode. UMB (EV-DO Revision C) In December 2006, CDG (CDMA Development Group) selected UMB (Ultra Mobile Broadband) as the brand name to describe the advanced technologies and services that will be supported by the CDMA2000R 1xEV-DO Revision C (Rev. C) standard. The UMB air interface standard was published by 3GPP2 in April 2007 as 3GPP2 C.SP0084 (000-009). UMB combines the best aspects of CDMA, TDM, OFDM, and OFDMA into a single air interface using advanced and highly optimized control and signaling mechanisms. It also incorporates advanced antenna techniques such as MIMO and SDMA. The name Ultra Mobile Broadband communicates the key attributes of the technology. Some basic terminology is as follows: Ultra: An ultra fast technology that supports more than an order of magnitude increase in broadband data throughput rates to economically deliver IP-based voice, multimedia, broadband, information technology, entertainment, and consumer electronic services within most kinds of devices. Mobile: A platform that supports several wireless services within a full mobility envi- ronment and thus differentiates itself from Wi-Fi, WiMAX, UWB (Ultra Wideband), and SO on. Broadband: high-speeds that are in the order of 100s of megabits per second; next-generation capabilities, beyond 3G. The key features of UMB are [11]: Multiple radio and advanced antenna techniques: Multiple Input Multiple Output (MIMO) and Space Division Multiple Access (SDMA). Improved interference management techniques. high mobile broadband peak data rates: Up to 280 Mbps peak data rate on forward link in 20 MHz. Up to 84 Mbps peak data rate on reverse link in 20 MHz. Ultra-low network latency: An average of 16.8 msec (32-byte, Return Time Transmission) end-to-end network latency. Enhanced VoIP capacity and user experience: Up to 500 simultaneous VoIP users (10 MHz FDD allocations). Next Generation Mobile Communications Ecosystem S