【作者】 罗青全；

【导师】 蒋良成；

【作者基本信息】 东南大学 ， 通信与信息系统， 2006， 硕士

【摘要】 多码道技术广泛地应用于第三代移动通信系统,灵活地为用户提供高速分组数据业务。多码道技术的基本思想是采用正交扩频码为用户分配多个码道。在单径环境下,接收的多码道信号之间保持正交;但是在多径环境下,由于多径不同时延,用户内部多码道之间的信号不再保持正交,不同延迟多径之间的互相关产生了多码道干扰(MCI)。多码道干扰严重地影响了系统性能。本文首先介绍了多用户检测系统模型和非线性多用户检测算法;得到一般多码道通信的发射系统和应用迭代干扰抵消的多码道接收系统模型;并推导了一般多码道通信系统的迭代干扰抵消算法。针对EV-DO前向链路多码道通信系统,本文首先分析了EV-DO前向链路接收系统的符号级迭代干扰抵消和chip级迭代干扰抵消模型;在此基础上,详细地推导了应用于EV-DO前向链路接收系统的符号级迭代干扰抵消和chip级迭代干扰抵消算法。接下来本文研究了EV-DO前向接收系统的符号级和chip级迭代干扰抵消的基本仿真性能。仿真结果表明:迭代干扰抵消较好地解决了多码道通信系统在多径衰落信道中高速传输数据的问题。针对迭代干扰抵消算法的复杂度,本文研究了多种降低算法复杂度的实现方法。并分析了迭代次数和数据存储位数对系统性能的影响。论文第五章介绍了EV-DO前向链路发射系统;然后详细地设计了前向基本性能接收系统中的信道估计。最后,论文给出了前向链路基本性能接收系统的仿真曲线。更多还原

【Abstract】 Multi-Code technique is widely used in the third generation mobile communication systems,and flexibly provides high-rate packet data services for users. The basic idea of Multi-Code technique is to assign multiple coded channels to any given user by orthogonal codes. The received multi-code signals maintain orthogonal to each other in single-path environments. However, in multi-path environments, these intra-user multi-code signals from different delay paths are no longer orthogonal to each other, the cross-correlation between different delay paths results in Multi-Code Interference (MCI). MCI degrades the system performance.At the first part of this thesis, a signal model of Multi-User Detection (MUD) and non-linear detection algorithms are described. Base on a common multi-code transmission system and receiving system with Iterative Interference Cancellation (IIC), we investigate the signal models of symbol-level IIC and chip-level IIC in forward link receiving system of EV-DO, deducing the algorithms of symbol-level IIC and chip-level IIC. Then we study the basic performances of EV-DO forward link receiving system with symbol-level IIC and chip-level IIC. The simulation results show that IIC is comparatively a good solution to the problem of high-rate data transmission in forward link of EV-DO system. Focusing on the complexity of IIC algorithms, we propose different methods to reduce them. The Iterative time and bit-width’s impacts on the performances of EV-DO system are also investigated.The forward link transmission system of EV-DO is described in chapter five. Then we exhibit the design of the channel estimation of basic receiving system detailedly. The performances of basic forward link receiving system are presented at the end of chapter five.更多还原