Unit_8_CDMA_Communication_System[1]

1、8.1.1 Access to CDMA Communication SystemAccess to CDMA communication system is defined as the entire process from the MSs turning-on to its successful register in CDMA system. The state of this process is usually called initialization. As the first action of the handset during this period, it judge

2、s which mobile communication system it will work in, GSM or CDMA? This is determined by the relevant information stored in the SIM card (for GSM/GPRS system) or UIM card (for CDMA system) of the MS. If the latter one is chosen, the mobile station then starts to detect the ceaseless pilot and synchro

3、nization signals from surrounding CDMA base stations at once. Although the PN sequences in pilot signal of each base station are of the same structure, they all have different offsets with each other. As long as the mobile station changes the offset of its local PN sequence, it can immediately detec

4、t the base stations around. By means of comparing intensities of these pilot signals, the MS makes choice of the present base station it should belong to at once. Now the mobile station sends its request of accessing to CDMA network to the selected BS through return channel. After receiving this req

5、uest, the BS then transmits an authenticating parameter and encryption parameters group from the Visitor Location Registry of Mobile Switching Center (MSC/VLR) to the MS through forward channel. According to a preset algorithm, then the MS calculates a response parameter by using parameters from the

6、 BS and the subscribers identifying data for authentication stored in UIM card, and then submits the response parameter to the MSC/VLR through the BS. After comparison between the receiving response parameter and that in encryption parameter group in the MSC/VLR, the MS then will be regarded as a le

7、gal terminal and can immediately enjoy all corresponding CDMA services only when the two parameters are completely the same, otherwise, the MS will be regarded as a lawless one and permitted to access to CDMA network.8.1.2 Standards of CDMAThe technical standards of CDMA cellular mobile communicatio

8、n system are issued by American National Standard Institute (ANSI). Telecommunications Industry Association (TIA), a subordinate department of ANSI, mainly takes charge of developing Interim Standards (IS) serial standards such as IS-95、IS-41 and so on. These IS standards all have time limitation wi

9、th 5 years period of validity initially and now 3 years. IS-95A is a technical standard of narrow CDMA (N-CDMA). The developing version of IS-95A is IS-95B which can satisfy the requirement of higher bit rate traffics. The max bit rate that IS-95B can supply is as high as 115kb/s in theory, but only

10、 64kb/s actually.IS-95A and IS-95B form IS-95 which is technical standards of the second generation CDMA cellular communication system. CDMA One is the appellative of all kinds of CDMA products with IS-95 as the core technical standard.CDMA 2000, the 3G CDMA mobile communication standard instituted

11、by TIA, is one of the three accredited standards (CDMA2000, W-CDMA, TD-SCDMA) relating to the 3G cellular mobile communication and a technique system scheme evolving from IS-95 to the 3G. Its a broadband CDMA technique. Its max indoor data rate is not less than 2 Mb/s, 384kb/s on walking and over 14

12、4kb/s on running automobile. CDMA2000 1X is the first stage of CDMA 2000 and its data rate is higher than IS-95, but lower than 2Mb/s. It can support data transmission at the rate of 308kb/s as well as mobile IP traffic when packet switching is adopted in the network. 8.1.3 Basic Parameters of CDMA

13、Communication SystemCDMA mobile communication system adopts CDMA/FDD access method, which means that the permitted channel bandwidth is firstly divided into many sub-channels, and then each sub-channel can support many links. Thus when a CDMA subscriber needs to start a communication process, he can

14、 be assigned an exclusive link through different PN sequence for his communication. The detailed CDMA sub-channels and corresponding frequency and the basic parameters of CDMA in 800MHz are respectively listed in form 8-1 and form8-2. The minimum channel interval (central frequency difference betwee

15、n two carrier frequencies) is 1.23MHz.The cycle length of pseudo random sequence in CDMA is 32768 (215) code chips, with 64 code chips merge to a modulation code pattern. It can hold 512 base stations in a CDMA cellular system with 1.25MHz bandwidth.CELP (Code Excited Linear Prediction) coding algor

16、ithm is adopted in CDMA for voice code, which is also called QCELP (Qualcomm Code Excited Linear Prediction). By the CELP, audio signals can be transmitted with different rate of 9.6kb/s, 4.8kb/s, 2.4kb/s, 1.2kb/s according to its different input.CDMA cellular system utilizes timing mark of Global P

17、osition System (GPS). Each base station is deployed with a GPS receiver for its Universal Timing reference.8.1.4 UIM CardUIM card is a smart microprocessor with integrated CPU, ROM, RAM, EPROM/E2PROM and serial communication unit on it, while abbreviation UIM means User Identity Model. Each UIM card

18、 preserves relevant information of its user and others, which can help the MSs operation through the access control to all types of data, i.e., the subscribers identity authentication calculation. Generally, information in a UIM card can be approximately divided into the following three kinds. Infor

19、mation for user identification and authentication: such as the International Mobile Subscriber Identification Number (IMSI), the proprietary authentication parameters of CDMA system etc.Service information：information about traffics in CDMA system stored in HLR, such as state of short message.Inform

20、ation relating to the MSs performance：majority are parameters, such as preferred system and channel and so on.Besides, subscriber can save his own information in UIM card, such as DN.initialization inilaizein n. 设定初值,初始化relevant relivnt adj. 有关的, 相应的local lukl adj. 地方的, 当地的, 局部的, 乡土的immediately imi:

21、djtli adv. 立即, 马上, 直接地intensity intensiti n. 强烈, 剧烈, 强度；亮度return channel 反向信道authenticate :entikeit v. 鉴别，证明是真的encryption inkripn 计 加密术,密码术Visitor Location Registry of Mobile Switching Center (MSC/VLR) 移动交换中心的访问位置寄存器forward channel 前向信道preset pri:set vt. 预先安置；预先调试algorithm lgrim n. 算法；十进位计数法calculat

22、e klkjuleit v. 计算, 考虑, 计划, 打算subscriber sbskraib n. 订户, 签署者, 捐献者submit sbmit v. (使)服从, (使)顺从 vt. 提交, 递交standard stndd n. 标准, 规格 adj. 标准的, 第一流的American National Standard Institute (ANSI) 美国国家标准协会Telecommunications Industry Association (TIA) （美国）电讯工业协会Interim Standards (IS) 临时标准，过渡标准Limitation limitei

23、n n. 限制, 局限性；缺陷，弱点；N-CDMA 窄带码分多址traffic trfik n. 交通, 贸易, 交通量, 通信量appellative peltiv adj. (人或物的)名称的, 通称的 n. 通称名词, 普通名词, 称呼broadband br:dbnd 宽带indoor ind: adj. 户内的, 室内的packet switching 分组交换exclusive iksklu:siv adj. 排外的, 独占的, 唯一的, code chip 码片merge m:d v. 合并, 并入, 结合, 吞没, 融合(Qualcomm) Code Excited Linea

24、r Prediction（(Q)CELP）码激励线性预测编码Global Position System (GPS) 全球定位系统deployed diplid v. 展开, 配置；部署EPROM n. 可擦可编程只读存储器, 电可编程只读存储器E2PROM n. 计电可擦除只读存储器abbreviation bri:viein n. 缩写, 缩写词User Identity Model（UIM）card 用户识别模块卡International Mobile Subscriber Identification Number (IMSI) 国际移动用户识别码8.1 Please transla

25、te the following Chinese words into English, and write out the corresponding English abbreviation if existing. 美国国家标准协会 电讯工业协会 用户识别模块 分组（包）交换 码激励线性预测编码 全球定位系统 格林威治时间 国际移动用户识别号8.2. Please translate the following sentences into Chinese. Taking no account of price, which handset do you prefer, the GSM

26、handset or the CDMA one? Because of his sudden demission that year, everything in the company was in a state of disorder. The busmen have stated that the strike will continue until general agreement is reached about pay and working conditions. The Town Council spent a lot of money to preserve the ol

27、d castle and other places of historic interest. Keep this enchiridion for the handset carefully for reference at any moment. The newly introduced mobile service named “mobile bank” is of universal interest; each of us is scanning and learning how to operate it on handset. Can the mobile communicatio

28、n techniques set of GSM merge into the techniques set of CDMA? If yes, what communication system will result? The present GPRS cellular mobile communication system adopted by China Mobile has evolved from GSM system though rebuilding and upgrade. Intelligent network is core of the 3G mobile communic

29、ation system. Till now, there are three accredited versions of 3G mobile communication system. As his faithful fan, I hurried to the nearby bookshop and bought the novel the day of its issue. There are several indexes of the system designed by you are not up to the industry standard. If the financia

30、l status permits, I want to rebuild and upgrade our company Intranet network. I hope you can submit you term papers before the deadline. This result has already been closely calculated. There is no probability for error. In the year-end dinner party last night, our boss compared the company R&D

31、department to his lover. The carrier synchronization means that the local carrier generated at receiver keeps the same frequency and phase with that of carrier in signals received at receiver. We cant judge what he really meant by doing so till we know all the circumstances. The scientists are able

32、to calculate accurately when the spaceship will reach the moon. To all appearances, the ambiguity of LCD in your handset issues from humidity of circuit board. I guess youve lost it into water, havent you?8.3 Read the following sentences carefully, and fill the brackets with correct words, phrases,

33、abbreviations and numbers according to the text.1. Access to CDMA communication system is defined as the entire process from the MSs ( ) to its successful ( ) in CDMA system. The state of this process is usually called ( ). As the first action of the handset during this period, it ( ) which mobile c

34、ommunication system it will work in, GSM or CDMA? 2. Although the PN sequences in pilot signal of each base station are of the same structure, they all have different ( ) with each other. As long as the mobile station changes the offset of its ( ) PN sequence, it can immediately detect the base stat

35、ions around. By means of comparing ( ) of these pilot signals, the MS makes choice of the present base station it should belong to at once. 3. According to a preset algorithm, then the MS calculates a ( ) parameter by using parameters from the BS and the subscribers identifying data for authenticati

36、on stored in ( ) card, and then submits the response parameter to the MSC/VLR through the BS. After comparison between the receiving response parameter and that in encryption parameter group in the MSC/VLR, the MS then will be regarded as a ( ) terminal and can immediately enjoy all corresponding CD

37、MA services only when the two parameters are completely ( ), otherwise, the MS will be regarded as a ( ) one and permitted to access to CDMA network.4. The technical standards of CDMA cellular mobile communication system are issued by ( ). TIA mainly takes charge of developing Interim Standards seri

38、al such as ( )、IS-41 and so on. These IS standards all have time ( ) with 5 years period of ( ) initially and now ( ) years. 5. IS-95A is a technical standard of ( ). The developing version of IS-95A is ( ) which can satisfy the requirement of higher bit rate traffics, with the max bit rate of 115kb

39、/s in theory but only ( )kb/s actually. IS-95A and IS-95B form ( ) which is technical standards of the second generation CDMA cellular communication system. CDMA One is the appellative of all kinds of ( ) products with ( ) as the core technical standard.6. The three accredited standards of 3G cellul

40、ar mobile communication is CDMS2000, ( ) and ( ). CDMA 2000 is a broadband CDMA technique evolved from IS-95, with the max indoor data rate no less than ( )Mb/s, 384kb/s on walking and over ( )kb/s on running automobile. 7. CDMA mobile communication system adopts ( ) access method. When a CDMA subsc

41、riber needs to start a communication process, he can be assigned an exclusive ( ) through different ( ) sequence for his communication. The minimum channel interval (central frequency difference between two carrier frequencies) is ( )MHz.8. The cycle length of pseudo random sequence in CDMA is ( ) c

42、ode chips, with ( ) code chips merge to a modulation code pattern. It can hold ( ) base stations in a CDMA cellular system with ( )MHz bandwidth.9. Adopting ( ) for voice signal code, audio signal in CDMA can be transmitted with ( ) kinds rate of 9.6kb/s, ( )kb/s, ( )kb/s, 1.2kb/s according to its d

43、ifferent input.10. UIM card is a smart ( ) with integrated ( ), ROM, RAM, EPROM/E2PROM and serial communication unit on it. Each UIM card preserves relevant information of its user and others, which can be approximately divided into kinds of: information for user ( ) and authentication; ( ) informat

44、ion; information relating to MSs ( ) and subscribers ( ) information such as DN.8.4 Judge each the following description correct or not, and write your answer in the bracket behind the sequence number respectively.1. （ ）As the first action of the handset during Access to CDMA communication system, i

45、t starts to detect the ceaseless pilot and synchronization signals from surrounding CDMA base stations at once. 2. （ ）After receiving the request of accessing to CDMA network from MS, the BS transmits an authenticating parameter and encryption parameters group from the Visitor Location Registry of M

46、obile Switching Center to the MS through forward channel.3. （ ）Although the PN sequences in pilot signal of each base station are of the same structure, they all have different offsets with each other. 4. （ ）After comparison between the receiving response parameter and that in encryption parameter g

47、roup in the MSC/VLR, the MS then will be offered all corresponding CDMA services. 5. （ ）The technical standards of CDMA cellular mobile communication system are issued by Telecommunications Industry Association.6. （ ）CDMA2000 1X is the alternative of CDMA 2000 with the data rate higher than IS-95 bu

48、t lower than 2Mb/s. 7. （ ）The minimum channel interval (central frequency difference between two carrier frequencies) is 1.23MHz.8. （ ）QCELP is a voice signal coding arithmetic with three kinds of coded voice signal transmitting rate of 9.6kb/s, 4.8kb/s, 2.4kb/s according to its different input.9. （

49、 ）CDMA cellular system utilizes timing mark of GPS, deployed in each BS with a GPS receiver for its Universal Timing reference10.（ ）Generally, information in a UIM card can be approximately divided into three kinds: Information for user identification and authentication; Information relating to the MSs performance and subscribers private information.8.1.1 接入接入CDMA通信系统通信系统一般将CDMA手机从开机到成功登录系统的整个过程称为接入CDMA系统，与此相应的手机状态则称为初始化状态。一旦开机，手机首先就根据其SIM卡（对GSM手机而言）或UIM卡（对CDMA手机而言）上的相关信息判断其所属通信系统是GSM还是CDMA？若答案