蜂窝无线通信系统的专题研究英文翻译

1、安徽大学题 目 蜂窝无线通信系统旳研究学生姓名 杨迪 专业班级 通信工程 学 号 P01114073 院 （系） 电子信息工程学院 指引教师（职称） 杨洋 RESEARCH OF CELLULAR WIRELESS COMMUNATION SYSTEM一：Conception AbstractCellular systems is also called the village system. Is all the areas covered by divided into several village, each district the radius of the visual user distribution density in 1 10 km or so. Set up a base station in every community service for users within the scope of this area. And through the district division to further improve the system capaci

2、ty.This system by mobile services switching center (MSC), base station (BS) equipment and mobile station (MS) (the user equipment) and the exchange center to the base station of a transmission line, as shown in the figure below. At present in the operation of the 900 MHZ (TACS) first generation mobile communication system simulation system and the second generation mobile communication (GSM) digital system belong to this category.Is the movement of the mobile station exchange center and the publ

3、ic telephone network (PSTN) is what we usually call telephone network is linked together, between the mobile switching center is responsible for the connection between the base station communication, call process, the mobile station (such as mobile phones) and subordinate to the base station to establish contact, by the base station connected to the mobile switching center again, finally access to the public telephone network. Cellular communication systems allow a large number of mobile users t

4、o seamlessly and simultaneously communicate to wireless modems at fixed base stations using a limited amount of radio frequency (RF) spectrum. The RF transmissions received at the base stations from each mobile are translated to baseband, or to a wideband microwave link, and relayed to mobile switching centers (MSC), which connect the mobile transmissions with the Public Switched Telephone Network (PSTN). Similarly, communications from the PSTN are sent to the base station, where they are transm

5、itted to the mobile. Cellular systems employ either frequency division multiple access (FDMA), time division multiple access (TDMA), code division multiple access (CDMA), or spatial division multiple access (SDMA).二：Introduction A wide variety of wireless communication systems have been developed to provide access to the communications infrastructure for mobile or fixed users in a myriad of operating environments. Most of todays wireless systems are based on the cellular radio concept. Cellular

6、communication systems allow a large number of mobile users to seamlessly and simultaneously communicate to wireless modems at fixed base stations using a limited amount of radio frequency (RF) spectrum. The RF transmissions received at the base stations from each mobile are translated to baseband, or to a wideband microwave link, and relayed to mobile switching centers (MSC), which connect the mobile transmissions with the Public Switched Telephone Network (PSTN). Similarly, communications from

7、the PSTN are sent to the base station, where they are transmitted to the mobile. Cellular systems employ either frequency division multiple access (FDMA), time division multiple access (TDMA), code division multiple access (CDMA), or spatial division multiple access (SDMA) .Wireless communication links experience hostile physical channel characteristics, such as time-varying multipath and shadowing due to large objects in the propagation path. In addition, the performance of wireless cellular sy

8、stems tends to be limited by interference from other users, and for that reason, it is important to have accurate techniques for modeling interference. These complex channel conditions are difficult to describe with a simple analytical model, although several models do provide analytical tractability with reasonable agreement to measured channel data . However, even when the channel is modeled in an analytically elegant manner, in the vast majority of situations it is still difficult or impossib

9、le to construct analytical solutions for link performance when error control coding, equalization, diversity, and network models are factored into the link model. Simulation approaches, therefore, are usually required when analyzing the performance of cellular communication links.Like wireless links, the system performance of a cellular radio system is most effectively modeled using simulation, due to the difficulty in modeling a large number of random events over time and space. These random events, such as the location of users, the number of simultaneous users in the system, the propagation conditions, interference and power level settings of each user, and the traffic demands of each user,combine together to impact the overall performance seen by a typical user in the cellular system. Th

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