In Td-scdma Base Station Received Signal Space-time Processing

Owing to its nature properties of CDMA system at anti-jamming,concealment and capacity, it has been considered as one of the main approaches of multiple access used in 3rd Generation Communication systems. But there's a problem that CDMA system's performance is often influenced by the channels'multi-paths, MAI and ISI. In order to solve these problems, researching Space-Time processing is to be a focus. Uniting signal's space domain and time domain will fully use advantages of both space signal processing technology and time signal processing technology. In this way, the influence of ISI and MAI can be effectively reduced and also the gain in multi-path and array-antenna can be largely improved, which can not be achieved by using only one antenna for time processing. As one of the main standards of 3G, TD-SCDMA system applies some key technologies such as Smart Antenna, Joint Detection and etc. Smart Antenna which forms multi-beams can establish a strong energy wireless link between Base Station and the expected users. Thus the interference can be largely reduced and the system capacity can be highly improved. While Joint Detection which fully uses all users'information such as spread codes, amplitudes and phases can also eliminate the influences of MAI and ISI. Though both The Smart Antenna and The Joint Detection can restrain the system's interferences, each of them has their own advantages. For example, The Smart Antenna has superiority in inter-cell interferences, while the Joint Detection doing well in intra-cell. So the combination of these two technologies is the research emphasis in this dissertation. The main works and conclusions of this paper are as follows: A general concept of SA and MUD are introduced. A channel model, based on which a ZF-JCE joint channel estimation scheme has been finished, for TD-SCDMA system uplink is made up. Several S-T(Space-Time) architectures are modeled and simulated to make a choice of the most suitable one for 2D RAKE receiver. The system-level simulation based on perfect CSI(Channel State Information) proves that the Space-Time 2D receiver achieves diversity and array gain from space domain.