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Leading EdgeAir Interface Evolution ofCDMA2000Zhu Xiaoguang, Yu Yuanfang, Xin Yu, Zhao XiaowuTh e T h i r d G e n e r a t i o nPartnership Project 2 (3GPP2)standards organization isdeveloping the next generation ofCDMA2000 wireless communications.CDMA2000 has a long-term evolutionpath which offers significant benefitssuch as enhanced technologicalperformance, low-cost delivery andshort time-to-market. The CDMA2000evolution includes air interfaceevolution and core network evolution.Fig.1 demonstrates the evolution pathof the CDMA2000 air interface.Fig. 1 CDMA2000 roadmapEach step in the evolution ofCDMA2000 capitalizes on theinherent advantages of CDMAwhile introducing new technologies,including Orthogonal FrequencyDivision Multiplexing (OFDM)or OFDM Access, multiple-inputmultiple-output (MIMO), and spacedivision multiple access (SDMA), tooffer high network capacity, high datarates, and low latencies, minimizingthe operational cost.EV-DO Rev. BThe EV-DO Rev. B or multi-carrierEV-DO standard is the “CDMA2000High Rate Packet Data Air InterfaceSpecification” published in May 2006by 3GPP2. Rev. B provides higherpeak data rates and improved supportfor delay-sensitive applications. Fig. 2is a basic comparison among differentEV-DO technologies.Numerous techniques are used toenhance the performance of EV-DORev. B. These include:● Channel aggregation that allowsoperators to combine 1.25MHzchannels, the current 1x channelwidth in agglomerations of up 15or 20MHz total which would allow73.5Mbps downlinks● Multi-carrier EV-DO which supportsthe symmetric and asymmetricforward and reverse link carriers● Multi-carrier terminals supportingRev. A devices and operation onnon-contiguous carriers● Improved HARQ and multi-userdiversity in the frequency domainto achieve higher spectral efficiencyfor the forward link● Support flexible duplexer spacing,which enables hybrid frequencydeployment scenarios6 ZTE TECHNOLOGIES