多对多通信

Firstly the basic principle of OFDM and its anti-multi-path-fading are briefly introduced in this paper. Then basing on this point, we researched the basic principle, the coding designing and the algorithm of the signal detection of these MIMO-OFDM systems. At the same time, the performances of STBC-OFDM and SFBC-OFDM were analyzed and simulated under short wave circumstance, and got some useful conclusions, they have certain reference value for more research of short wave communication in future.

本文首先介绍了OFDM系统的基本原理以及它对抗多径的基本原理，然后在此基础上，对其所形成的几种MIMO-OFDM系统的基本工作原理，码字设计以及相应的信号检测算法进行了研究，详细分析研究了STBC-OFDM和SFBC-OFDM系统的性能并在短波信道下对其性能进行了仿真和对比分析，得出了有用的结论，这对以后短波通信的深入研究具有参考价值。

With the development of computer and communication technology, it is more and more indescribable that the people's demand in the Internet, so the more and the better control mechanisms which could smooth the network act very important actions, the congestion control is one of the crux, that is how avoid or eliminate the congestion in the network availability, so as to the network runs in the best and the low-grade congest state basically.

随着计算机和通信技术的发展，人们对Internet的需求已经越来越超乎想象，因此更多、更合理的控制机制对现有网络的顺畅运作起着非常重要的作用，其中最基本、最关键的就是拥塞控制，即如何有效防止或消除网络出现的拥塞，使网络基本运行在轻度拥塞的最佳状态。

This paper studies the performance of the system of UWB wireless communications in the multi-user environment.

本文在多径与多用户环境下，对超宽带无线通信系统性能进行了相关的理论研究。

Multipath is the main character of the mobile communication system. Multipath signal of the target user turn out to be the ISI of the main path signal, multipath signal of the other users cause severe MAI since the orthonormality among the spreading codes is destroyed.

多径干扰是移动通信系统中的常见干扰，目标用户的多径信号对主路径信号引入了码间干扰，其它用户的非同步路径信号由于破坏了扩频序列的正交特性而导致了强的多址干扰。

Similarly, investigations on the information encoded in finite physical resources will also be helpful for improving the efficiency of state measurement, storage, etc.. This dissertation focuses on some theoretical investigations of quantum state estimation together with discrimination process, and is organized as follows. In the first chapter, we introduce some basic concepts and related background materials, including the theory of quantum operation and unitary group representation, which is helpful for understanding the following content of this dissertation.

在量子密码通信的安全性研究中，测量可获取信息直接关系到窃听能否成功，这实际上对应于量子态的操作和识别过程；在量子通信信道容量、以及态编码的研究中，考察如何利用有限的物理资源标识尽可能多的量子态信息，对提高信息测量、存储的效率都很好的指导意义。

Integrating technology in fields such as sensing,MEMS,wireless communication and parallel information processing,wireless sensor networkscan easy realize the purpose of temperature monitoring totally in real time through integrate micro sensors. After information is acquisited,the embedded module processes the signals and then the data is sent out to the terminal through self-organized wireless networks.

中文摘要：无线传感器网络综合了传感技术、MEMS技术、无线通信技术和分布式信息处理技术等，能够通过各类集成化的微型传感器，实时、全方位地监测被测对象的信息，通过嵌入式系统对信息进行处理，并通过自组织无线通信网络，以多跳中继方式将所感知信息传送到终端。

A narrowband interference has a greater power spectral density. Thus it will bring more strong devastation to the DSSS system than a broadband one does.So it is difficult for DSSS system to ensure a high quality of communication by itself when strong interference exists, even communication may be intermitted.

窄带干扰(Narrow-Band Interference，NBI)由于其功率谱密度比宽带干扰高得多，所以它对DSSS系统的破坏性更强，当有强窄带干扰存在时仅靠系统自身的抗干扰能力很难保证系统高质量的通信，甚至可能造成系统通信中断。

This system will adopt the minimum system of the one-chip computer some many temperature control will combine with RS485 communication, the control room that can be relatively transported controls a lot of temperature control points of the scene.

本系统采用单片机最小系统将多点温度控制和RS485通信相结合，可在较运的控制室对现场的多个温度控制点进行控制。

For the need of large scale parallel computing based on Data Grid that is composed of the multi-clusters, the single cluster grouping communication model for multi-level grouping communication has been researched.

软件简介：针对基于多计算机机群构成的网格的大规模并行计算的需要，对多级分组通信模型的单一机群分组通信进行了研究。

Multicarrier and multicarrier CDMA systems are the candidates with a greatapplied foreground for future mobile communications system.Some keytechniques in the two kinds of systems,including the reduction of peak-averagepower ratio and so on,are studied in this dissertation.The main contents ofthe dissertation are as following:(1) The way to constitute a multicarrier signal by using any onecomplementary code from multiphase complementary code pair is proposed,andthe upper bound on crest factor for a multicarrier signal is studied.

多载波及其多载波CDMA系统是未来移动通信系统一种很有应用前景的侯选方案，本文针对这两种系统中的峰平功率比减小等关键技术进行了研究，主要内容包括：(1)提出了利用多相互补码对中任一互补码构成多载波信号的方法，研究了多载波信号峰值因子的上边界。

With Death guitarist Schuldiner adopting vocal duties, the band made a major impact on the scene.

随着死亡的吉他手Schuldiner接受主唱的职务，乐队在现实中树立了重要的影响。

But he could still end up breakfasting on Swiss-government issue muesli because all six are accused of nicking around 45 million pounds they should have paid to FIFA.

不过他最后仍有可能沦为瑞士政府&议事餐桌&上的一道早餐，因为这所有六个人都被指控把本应支付给国际足联的大约4500万英镑骗了个精光。