In this dissertation , multiuser detection and space - time processing are combined to suppress multiple access interferences and inter - symbol interferences ( isi ) jointly in multipah fading channels with large delay spread 本文组合多用户检测和空时处理技术，在大时延扩展的多径衰落信道条件下，研究多址干扰和符号间串扰的联合抑制。
Multi - path fading and doppler shift of wireless mobile channels would generate interference to signals , as a result , waveform of the received signal would be distorted , and channels would be interrupted if the interference is severe 无线移动信道的多径衰落和多普勒频移会对信号产生干扰,导致接收信号波形失真,严重者会造成通信的中断。
And the most advantage of ofdm is that it can convert high - rate data stream into the low - rate and reduce data bandwidth so that multi - path - fading can be transformed into flat fading in wireless circumstance 这种调制技术的最大的好处就是将高速的数据流，变换成并行的低速数据流，减小了数据带宽，从而可将无线环境中的多径衰落(频率选择性率落)转换成平坦衰落。
In current communication system , the application of dual - band dual - polarized antenna satisfies the needs of communication system ’ s upgrade , solves the problem of multipath fading , reduces the number and lowers the cost of the antennas 在现代通信系统中,双频双极化天线的应用能够满足通信系统的不断升级的要求,能有效解决多径衰落问题,能减少天线数量、降低天线成本。
Recently , chaos shift keying system attracts much attention in chaos - based communication system . this paper focus mainly on analyzing the performance of differential chaos shift keying ( dcsk ) system in anti - jamming , multi - path fading and multiple access ability 本文的主要工作是对非相干差分混沌键控( dcsk )系统的抗多径衰落、抗干扰,及其多址接入能力进行详细分析讨论。
The key technologies for 3g include multi - user detection , adaptive antenna , rake receive , power control and so on . these key technologies complement each other and all of them are the focus of present research Cdma通信系统的关键技术包括有抗干扰(多用户检测) 、抗多径衰落(天线分集和rake接收) 、抗远近效应(功率控制)等，而它们之间又是相辅相成、互相补充的，均为当前研究的热点。
People used to focus mainly on modulating methods and noise performance of chaos - based communication system , but lack of multipath and anti - jamming performance analysis , which is one important performance of any communication system 以往对混沌通信系统的研究工作主要集中在调制方法和抗噪声性能分析上,而对其抗干扰和抗多径衰落性能分析较少,而这却又是衡量系统性能优劣的重要特征。
But it is not enough for a simple ofdm system to resist multi - path - fading . the multi - path - fading can be resisted efficiently and system ' s error bit rate performance can be improved if we combine ofdm , a high - rate modulation technology , with mimo 但是靠单纯的ofdm来抗多径是远远不够的，将无线局域网中的高速调制技术ofdm和mimo技术相结合，就可以有效地抗多径衰落，改善系统性能。
Simulation results reveal that awls method can track and estimate channel parameter well . a scheme which combines tals - ljade algorithm and zf - 2drake is proposed . this scheme uses tals - ljade algorithm to estimate the delay and doa , and then employs zf - 2drake receiver 仿真表明:在不同的多普勒频移情况下, awls能有效地估计出时隙中数据段的信道参数,很好地跟踪多径衰落信道的变化。
The detailed content of this paper is arranged as follow : 1 introduce the property of mobile communication channel , and discuss the interference and fading multipath that influence the quality and capacity of mobile communication 本论文的具体内容安排如下：一先介绍移动信道的特性，移动通信中的多径衰落和移动通信中的干扰，以及它们对移动通信的影响，从而说明引入智能天线的必要性。
