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CDMA2000 1x EV-DO Release0(DORel.0)作为因特网的无线延伸,其最初的设计目的是为了提供非对称的高速分组数据业务。它的前向链路采用了HARQ、多用户分集、自适应速率调整、虚拟软切换和自适应调制编码等多种关键技术,获得了良好的前向平均吞吐量。但是,随着多媒体数据业务的发展,各种新的业务形式不断出现,对系统带宽和QoS保证等方面的要求也不断提高,DORel.0在支持新业务方面也暴露了一些不足:反向吞吐量不足以开展多种应用;反向速率相对于前向速率偏小,限制了对称性数据业务的应用。为解决上述问题,2004年3月,3GPP2发布了1xEV-DORevA(DORevA)版本,除了将前向链路峰值速率提高到3.072Mbit/s之外,最大的改进是将反向链路的峰值速率提高到1.8432Mbit/s。同时,1xEV-DORevA在反向物理链路实现中引入高阶调制和HARQ技术,并通过反向MAC的流体控制(FluidControl)机制精确控制反向链路的T2P,进而提升ROT控制门限,大幅提高反向链路的传送速率和容量,同时进一步改善前向链路吞吐量,以支持对称性宽带多媒体业务,适应分组数据业务发展对系统容量的要求。
CDMA2000 1x EV-DO Release0 (DORel.0), a wireless extension of the Internet, was originally designed to provide asymmetric, high-speed packet data services. Its forward link adopts many key technologies such as HARQ, multi-user diversity, adaptive rate adjustment, virtual soft handover and adaptive modulation and coding to obtain a good forward average throughput. However, with the development of multimedia data services, new types of services are constantly emerging, and requirements for system bandwidth and QoS guarantee are also increasing. DORel.0 also reveals some deficiencies in supporting new services: reverse throughput Not enough to carry out a variety of applications; reverse rate relative to the forward rate is small, limiting the application of symmetric data services. In order to solve the above problem, in March 2004, 3GPP2 released the 1xEV-DORevA (DORevA) version. In addition to increasing the forward link peak rate to 3.072 Mbit / s, the biggest improvement is that the reverse link peak rate Increase to 1.8432Mbit / s. At the same time, 1xEV-DORevA introduces high-order modulation and HARQ technology in reverse physical link implementation, and precisely controls reverse link T2P through reverse MAC fluid control so as to increase ROT control threshold Reverse link transmission rate and capacity, while further improving the forward link throughput to support symmetric broadband multimedia services to adapt to the development of packet data services system capacity requirements.