1、附录 外文翻译 (原文 ) RESEARCH OF CELLULAR WIRELESS COMMUNATION SYSTEM Abstract 1897, Marconi demonstrates the first practical application of the mobile radio communication, opening up a precedent of mobile communication, wireless communication in the modern sense was born. From that day onwards, the wirele
2、ss communication technology is committed to achieving better communication quality, lower power consumption, smaller size and cheaper price. In the next 60 years, a number of landmark technological breakthroughs to promote the further development of mobile communications. Know the early 1980s, with
3、the establishment of a cellular mobile communication systems, mobile communication system has now entered a period of prosperity and development. The cellular system has experienced rapid exponential growth, clearly showing that wireless communication has a bright future.Cellular communication syste
4、ms 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 mic
5、rowave 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 transmitted to the mobile. Cellular systems employ either frequen
6、cy division multiple access (FDMA), time division multiple access (TDMA), code division multiple access (CDMA), or spatial division multiple access (SDMA). 1 Introduction A wide variety of wireless communication systems have been developed to provide access to the communications infrastructure for m
7、obile or fixed users in a myriad of operating environments. Cellular mobile communication system by the exchange of Network Subsystem (NSS), the wireless base station subsystem (BSS) and mobile station (MS) has three major components. Switched network subsystem (NSS) completion of the exchange funct
8、ional and customer data, and mobility management, security management database functionalityMost of todays wireless systems are based on the cellular radio concept. Cellular communication systems allow a large number of mobile users to seamlessly and simultaneously communicate to wireless modems at
9、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
10、 Public Switched Telephone Network (PSTN). Similarly, communications from 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 (CD
11、MA), or spatial division multiple access (SDMA) .Cellular wireless network due to its sophisticated networking technology, good coverage and reasonable cost of network construction has been the largest range of applications. GSM / GPRS, CDMA1X, and WCDMA, CDMA2000, and TDS-CDMA cellular radio networ
12、k of the areas. The first generation of mobile communication system is characterized by: frequency division multiple access, analog modulation and demodulation, the frequency of low resource utilization, system capacity is low, serious interference, poor communication quality, and large terminal equ
13、ipment. MS: Mobile Station, the users mobile terminal. BSS: Base Station Subsystem, including a base station controller BSC and base stations starting the BTS. BTS is responsible for the mobile station via the air interface communication； BSC is responsible for controlling one or more of the BTS. MS
14、C: MobileSwitchingCenter, responsible for one or more of the BSS. Completion of the MS mobility management and business as well as the PSTN exchange. HLR, VLR is: are responsible for the records to the local user information registered in the local and roaming user information in the field. MSC thro
15、ugh these two databases to user mobility management and the correct exchange of the user service. The EIR, AUC: mobile devices, and user authentication center, responsible for the management of user rights. Obviously, the core of the GSM wireless network for the MSC by the MSC, VLR and HLR, to compl
16、ete a voice call business circuit-switched mobile station access and mobility management. GPRS / GSM dual-mode mobile station, mobile station (MS), GSM base stations (BSS) subsystem made the appropriate hardware and software extensions. Introduced in the core network, the SGSN (and the GGSN two new
17、network device node SGSN,) GGSN logo both on the 7th signaling address and data GGSN IP address of GSN (SGSN or GGSN), the communication between using the IP GSN and MSC, HLR, and other entities of communication No. 7 signaling address.CDMA its market fundamentals in the United States. Europes secon
18、d-generation mobile communication system uses a TDMA standard, later developed into todays GSM network.Relative to the second-generation GSM network, GPRS network multiple components of the adjustment of the function module of the new features include: (1) mobile station (MS) must be GPRS or GPRS /
19、GSM dual-mode mobile station. The original GSM network is only used as a voice call: GSM upgrade to the GPRS network, the MS with GPRS network to transmit voice packet switching circuit switching and transmission of data in two ways, and therefore more diverse functions and purposes. (2) the origina
20、l GSM base stations (BSS) subsystem made the appropriate hardware and software extensions, base transceiver stations BTS units still only connected with the base station controller BSC, no new hardware interfaces, only an increase in the BTS software unit (CCU), the original BTS of the GSM network f
21、or the GPRS network. BSC is still connected at the same time many of the BTS, BSC is not only the need for software upgrades for the additional packet processing capabilities, but also increase the hardware interface of the connected with the SGSN Packet Control Unit (PCU). In the GPRS network, the
22、wireless signal issued by the MS for data or voice in two ways, responsible for the identification signal from the BTS data form: If the only voice information from the BSC to transfer the data to the MSC (which plays the voice switch role)； containing data from the PCU in the BSC new interface, sep
23、arated from the voice services to data services and data transmission to the SGSN, to control the allocation of the radio channel. (3) software that supports GPRS network switching subsystem (SS) (such as HLR, VLR, MSC, etc.), original equipment. (4) the introduction of the SGSN and GGSN of two new
24、network equipment in the core network nodes, thereby increasing the data-based voice services on the basis of business. Wireless communication links experience hostile physical channel characteristics,such as time-varying multipath and shadowing due to large objects in the propagation path. In addit
25、ion, the performance of wireless cellular systems 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 seve
26、ral 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 impossible to construct analytical solutions for link performance when error control coding, equalization,
