Chapter 2 introduces the theory of cellular system design , including several elements usually used in design . at the same time chapter 2 gives out the effects that these elements bring to the system performance 第二章介绍了蜂窝通信系统设计中的几个基本要素，并重点介绍了每个要素对系统容量、服务质量等系统性能参数的影响及解决办法。
Power control is the key technology of cdma cellular system . in this paper , we present a power control algorithm based on partially compensating signal to interference ratio , and it can improve system capacity and system performance 功率控制是cdma蜂窝通信系统的关键技术.本文给出一种部分补偿信干比的功率控制算法，可以提高系统的容量，改善系统性能
The layered wireless self - organizing routing network ( lwsrn ) described in this paper has a new network architecture that combines the self - organizing feature of ad hoc networks and the user access control of cellular networks 本课题涉及的分层结构无线自组织网络是一种结合了adhoc网络自组织能力和移动蜂窝通信系统中移动用户接入方式的网络体系结构。
The chief difference between mobile ad hoc networks and conventional cellular technology is the apparent lack of a centralized entity within an ad hoc network . there are no base stations or mobile switching centers in an ad hoc network 它与传统的蜂窝通信系统之间最重要的区别是前者不需要中心控制的功能实体，网络中没有固定的基站和移动交换中心，因此，所有协议都必须以分布式工作。
The practical aspects of these multiple access techniques are also discussed and compared . the hybrid schemes , which combine the advantages of both orthogonal and non - orthogonal techniques , can provide promising solutions for future wireless cellular communications 我们讨论和比较了这些接入方式在实际应用方面的因素,指出综合正交和非正交方式优点的hybrid系统可能是未来无线蜂窝通信的一种可行方案。
They also offer very small , high - tech cameras - not like the big ones in the movie - that will give a 360 - degree view of the perimeter of the home , and ham radio systems that operate even if cellular and satellite communications have been knocked out 和电影里面的大的摄像头不一样，他们还提供了小的高科技的摄像头，那为整个屋子的周界提供了360度的视角，即使当蜂窝通信和卫星通信不能用的时候，还有无线电系统可以操控。
Traditional network can not communicate when it is moving , for equipments of network have been limited by line of network . as more and more portable computers coming forth , wildly been using and demand from national defence , people put forward new desire for network communication . the wireless mobile self - organizing network ( wmsn ) demonstrates a new kind of network architecture that combines with the self - organization of ad hoc networks and the user management of cellular networks 无线自组织网络又称无线移动自组织互联网，作为一种新型的无线移动网络，不像传统的网络，它不依赖于任何固定设施，而是通过移动节点间的相互协作保持网络互联，它结合了自组织网络的组网和移动蜂窝通信系统中移动用户管理的特点。
The advantages of using leo satellite are as following : on the one hand the satellite orbit is low , so the transmission delay is short , the power loss is small ; on the other hand the development of cell communication , multi - access , frequency multiplex and etc also provide a technique guarantee to the leo satellite - mobile - telecommunication . so the leo system is considered to be a satellite - mobile - communication system with a great future 低轨道卫星是一种运行于1000公里左右的高空中的人造卫星，利用leo卫星实现个人通信的优点在于：一方面卫星的轨道高度低，使得传输延时短、路径损耗小，多个卫星组成的星座可实现真正的全球覆盖，频率复用更有效：另一方面蜂窝通信、多址、点波束、频率复用等技术的发展也为低轨道卫星移动通信提供了技术保障。
Future wireless communication systems trend to provide multi - services to mobile users . cdma technique is adopted by the 3rd generation mobile communication systems due to its flexibility in supporting multi - services . how to keep qos of heterogeneous services and utilize the scarce radio spectrum resources is challenging for 3rd generation mobile communication systems in this thesis we developed a radio resource allocation framework for wireless code division access ( cdma ) networks that support multi - class traffic with different data rates and bit error rate requirements . we proposed a new resource allocation scheme using joint adaptive power control and mmse multiuser receiver in multipath fading system 为移动用户提供多种业务服务是未来无线通信网络的主要发展方向。由于cdma技术具有灵活支持多种业务的优点,因而被第三代移动通信系统所采纳。如何在恶劣的无线传播环境里以及用户运动且相互干扰的情况下为为各类业务提供qos保证,同时充分利用珍贵的无线频谱资源,是基于cdma技术的第三代蜂窝通信系统必须致力解决的问题。
Global system for mobile ( gsm ) is the first cellular communication system to specify digital modulation and network architectures and services . the number of countries that use the gsm system is more than 179 today . there are more than 200 million gsm mobile phone users in china the late 2002 全球数字移动通信系统( gsm )是世界上第一个对数字调制、网络层结构和业务做出详细规定的蜂窝通信系统，全世界有大约179个国家采用gsm标准建立了数字移动通信网络，我国从1995年开始建立gsm网络，发展至今已经拥有超过2亿的用户，成为全世界拥有gsm手机用户最多的国家。
