Basics of Cdma free essay sample

Part1 Basic knowledge of CDMA Agenda 1. Architecture of CDMA system/ Coverage Area Structure 2. Interface between different entities 3. Numbering plan Architecture of CDMA system MS Um Abis A B OMC BT S BSC MSC VLR D HLR H BSS C MSS AUC †¢MS: †¢BSC: †¢BTS: †¢MSC: †¢VLR: †¢HLR: †¢AUC: †¢OMC: Mobile Station Base Station Controller Base Transceiver Station Mobile Switching Center Visitor Location Register Home Location Register Authentication Center Operation and Maintenance Center 1. Main components of CDMA †¢MSS (Mobile Switching Sub-system) †¢BSS (Base Station Sub-system) †¢MS (Mobile Station) †¢OMC (Operation and Maintenance Center) . 1 Base Station Sub-system †¢Function It provides trunks between wireless part and fixed part of PLMN network. BSC BSC performs the controlling function and management. BTS BTS is in charge of wireless transmission. 1. 2 Mobile Switching Sub-system †¢Function —CDMA switching fu nction —Manage mobile subscriber data —Manage database for mobile service —Interface between CDMA network and other network (such as PSTN, other PLMN etc. ). †¢It includes 4 function units: MSC HLR VLR AUC 1. 2. Mobile Switching Center(MSC) †¢It is responsible for setting up, managing and clearing connections as well as routing the calls to the proper user. †¢ It provides the network interfaces, the charging function and the function of processing the signaling. †¢ MSC gets data for call handling from 3 databases: VLR/HLR/AUC †¢ GMSC(gateway):When a non-CDMA end subscriber calls a CDMA subscriber, the call will first be routed to a GMSC. †¢It can process the No. 7 signaling between BSS and MSC, and realizes the auxiliary radio resource management and mobile management. 1. 2. Visitor Location Register(VLR) †¢VLR is a dynamic database used by MSC for information index. It stores all related information of mobile subscribers that enter its coverage area, which enables MSC to set up incoming and outgoing calls. †¢Subscriber parameters include: subscriber number, location area identity(LAI), userâ₠¬â„¢s status, services which subscriber can use and so on. †¢When the subscriber leaves this area, it should register in another VLR, and the previous VLR will delete all the data about this subscriber. †¢ VLR can be built together with the MSC or set separately. 1. 2. Home Location Register(HLR †¢ HLR:It is a static database. When a user applies for mobile service, all data of this subscriber will be stored in HLR. †¢Information: -Subscriber information (ESN, MDN, IMSI, MIN), service information and valid term. -The mobile subscriber location (MSC/VLR address), so as to set up the call route to the MS. †¢ HLR can be built together with the MSC or set separately. 1. 2. 4 Authentication Center †¢ It is an entity to prevent illegal subscribers from accessing CDMA network. It can generate the parameters to confirm the subscriber’s identity. At the same time it can encrypt user’s data according to user’s request. †¢ Composition — Database save MIN,ESN, Authentication Key) — Generator of random number — Algorithm(CAVE algorithm) — AUC can be built separately or together with HLR 1. 3 Operation and Maintenance Center (OMC) OMC provides operation and maintenance services to the network operator, manages the registered subscriber information and conducts network planning to enhance the overall working efficiency and service quality of the system. Based on the main maintenance functions, there are two types of operation and maintenance centers: OMC-S and OMC-R. The OMC-S is mainly responsible for maintenance of MSS while the OMC-R is mainly for BSS. We also call OMC as background. wireless Area partition CDMA service area PLMNService area MSCService area Location area cell Wireless coverage area structure wireless Area partition †¢ Cell The smallest area that can not be divided. †¢ Location area: The area where MS moves without updating location. It includes some cells. It only belongs to one MSC. It includes one or more BSC. One location area has one LAI to identify each other. wireless Area partition †¢ MSC service area: The area that all the cells controlled by one MSC covered. One MSC composes one or more location areas. †¢ PLMN service area: It includes one or more MSC service areas. †¢ CDMA service area: It includes global PLMN networks . Agenda 1. Architecture of CDMA system / Coverage Area Structure 2. Interface between different entities 3. Numbering plan The interface and protocol between entities The difference between interface and protocol: †¢The interface: The connection point between two adjacent entities. †¢The protocol: To illustrate the rules followed when information exchanged at the connection point. The interface between entities MS U m MSC E Abis SCP PSTN ISDN PSPDN B D T2 BTS Q BSC Q A MSC/SSP C VLR Q N OMC SC M HLR H SCP SME AUC 1 . Um interface Um interface defines the communication interface between MS and BTS, also called air interface. †¢ It realizes the compatibility between all kinds of MS and different BTS, so that the MS can roaming. (It is an open interface) †¢ It adopts some anti-blocking technology and measurements to reduce interference and improve the frequency spectrum efficiency. †¢ It realizes the physical connection between MS and CDMA network. (that is wireless link). 2. Abis interface The interface between BTS and BSC, used for remote connection. †¢2. 048 Mbps PCM digital link 3. A interface †¢It is the interface between BSC and MSC †¢It is based on 2. 048Mbps PCM digital links †¢The standard protocols for this interface include IS634, IOS2. 4 and IOS4. 0, etc. †¢A-Interface is mainly used to transmit the following information: — BSS management information — Call processing — Mobility management †¢It is an open interface. 4. B interface †¢The interface between MSC and VLR. †¢ MSC transfer the location information of roaming subscriber to VLR. †¢ Query subscriber data from VLR when setting up the calls. Usually VLR is built with MSC together, so the interface turns to be an internal interface and has no standard rules. 5. C interface †¢The interface between MSC and HLR. †¢The system adopts IS-41D protocol. The interface is based on 2. 048Mb/s PCM digital link. †¢When a MS is called, MSC must query the called MS’s routing message from HLR through this interface to locate the called MS, and according to the record, HLR will return the routing message(MSC/VLR number) to MSC. 6. D interface †¢The interface between VLR and HLR. †¢The system adopts IS-41D protocol. The interface is based on 2. 48Mb/s PCM digital link. †¢The interface is used for exchange of s ubscriber location information, authorization information and service data. 7. E interface †¢The interface between MSC and MSC. It is used for channel change over between 2 MSC †¢The system adopts IS-41D protocol. The interface is based on 2. 048Mb/s PCM digital link. †¢When a mobile station roams from one MSC to another during the speaking, the MSC will perform handover to keep the subscribers conversation uninterrupted. In this case, data exchanging must be implemented between the MSCs. 8. Q interface †¢Interface between SC and MSC. †¢The system adopts ANSI-41E protocol. The interface is based on 2. 048Mb/s PCM digital link. †¢In submission and reception of short messages, short messages are transferred among the short message centers and the mobile switching centers. At the same time, when the subscribers short message capability changes, the mobile switching center should notify the short message center promptly. 9. Ai interface: The interface betwe en MSC and PSTN, used for setting up voice connection between PSTN and PLMN. Agenda 1. Architecture of CDMA system/ Coverage Area Structure 2. Interface between different entities 3. Numbering plan †¢ E. 164:The international public telecommunication numbering plan †¢ E. 212:International identification plan for mobile terminals and mobile users 1. Mobile Directory Number (MDN) †¢ †¢ the numbering format of MDN and HLR Number and Subscriber Number depends on specification by countries and not necessarily same as with CHINA An MDN number is the number dialed by the Caller. Composition of an MDN number. CC + MAC + H0H1H2H3 + ABCD International MDN National MDN CC: Country Code (CC=86 in China ) MAC: Mobile Access Code(China:133,134) H0H1H2H3 : to identify different HLR ABCD: mobile subscriber number . International Mobile Subscriber Identification number (IMSI) †¢IMSI can identify a mobile subscriber in the PLMN network. †¢IMSI is used in signaling in a CDMA network, stored in HLR, VLR and the UIM card. †¢Composition of an IMSI number: MCC + MNC + MSIN †¢MCC †¢MNC Mobile Country Code (MCC=460 in China ) Mobile Network Co de (China :03) †¢MSIN Mobile Subscriber Identification Number, a 10-bit algorism number, expressed as XX + HoH1H2H3 + ABCD XX is allocated by international organization (China:09 or 03) HoH1H2H3 is the same as HoH1H2H3 in the MDN number. ABCD is a subscriber number. 3. Mobile station Identification Number (MIN) MIN is the same as MSIN 4. SID Switch No. †¢SID: System Identification. Each mobile local network is assigned with an SID, which is decided by the headquarter. †¢Switch No. :To identify different equipments with the same SID. 5. HLRIN HLRID †¢HLRIN (HLR number) is used in the No. 7 signaling. Composition : MCC + MNC + XX + HoH1H2H3 + 0000 †¢HLRID:HLR Identification. Including: SID Switch No. 6 . MSCIN MSCID †¢MSCIN (MSC number) is used in the No. 7 signaling. Composition : MCC + MNC + XX + 44 + M1M2M3 + 100 M1M2M3: to identify different MSC/VLR †¢MSCID: MSC Identification. Including: SID Switch No. 7. Temporary Local Directory Number (TLDN) †¢TLDN is a number temporarily assigned by VLR of the called party. †¢In CDMA system, TLDN is used only when the calling and the called are not in the same MSC/VLR. †¢TLDN is released after the completion of the voice connection, then it can be assigned to another subscriber. †¢Composition of an TLDN number: CC + MAC + 44 + M1M2M3 + ABC 8. Location Area Identification number (LAI) †¢LAI is used to identify the location area. Its structure is: MCC MNC LAC MCC and MNC : same as the MCC and MNC in IMSI. LAC is a location area code that uniquely identifies each location area in our digital PLMN. It is a 2-byte hexadecimal BCD code represented by L1L2L3L4 (with the range of 0000 FFFF, able to define 65536 different location areas. ) 9. Global Cell Identification (GCI) †¢It identifies certain cell in a location area. †¢Structure: MCC+MNC+LAC+CI CI:2 bytes hexadecimal BCD code. 10. Electric Serial Number (ESN) It is set by the manufacture of the mobile station. The End Kuldeep Kumar