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A Brief note on MSC Based CDMA WLL Advantages of CDMA
ZXC10MSC/VLR/SSP ZXC10 MSC/VLR/SSP 1X stands for The CDMA mobile switching center/visitor location register product. It mainly implements the functions of the CDMA core network MSC and VLR. It can also integrate the functions of GMSC, SSP, TMSC2 and LSTP, and is characterized by modular design, advanced performances, system reliability, and standardized signaling interfaces. MSC is a functional entity that performs the controlling and switching of mobile subscribers within the area it serves, and it is automatic switching equipment for the traffic between MSCs or between MSC of CDMA network and switches of other public networks. MSC performs the common signaling function and billing function, and offers network interfaces. It performs the management of signaling system, wireless resource and A interface signaling between BSS and MSC. It also sets up the calling route for the called mobile subscribers if the function of GMSC has been integrated. VLR is a database and responsible for the storage and updating of data of mobile subscribers that roam to the service area of this VLR. The information includes user number, property, and location identification and service parameters. ZXC10 SSP mainly implements the SSF, CCF and the build-in SRF functions in the DFP. It performs service and call controlling and resource management. Based on the operation code, resource code, and detection point (DP) in the SCP message, ZXC10-SSP performs call procedure controlling and resource deploying, and returns the execution result and detected status to the SCP for it to determine the further service direction. TMSC comprises TMSC1 and TMSC2.
STP comprises HSTP and LSTP.
Technical specifications MSC system capacity: 600,000
VLR System Capacity: 800,000 HLR/AUC Home Location Register/Authentication Center ZXC10 HLR/AUC system produced by ZTE integrates the HLR with the AUC. The HLR is a central database to store the information of related subscribers in such aspects as ESN£¬MDN£¬IMSI£¬MIN£¬the service item information, the present location and the ratified valid time section. The AUC is a function entity processing authentication information related to mobile subscribers (MS). If the AUC is integrated with the HLR, the H interface becomes an internal interface. ZXC10 HLR/AUC can integrate with ZXC10 MSC/VLR/SSP if the subscriber number is small. ZXC10 HLR/AUC serves as the data processing center in CDMA network, primarily completing the subscriber service processing, subscriber data management, the signaling exchange, system maintenance, and service complaints solution via the SS7 connecting with other function entities. Technical Specifications
ZXC10SC (Short Message Center) Short Message Service Center system ZXSC100 comprises a series of products: short message center ZXC10 SC; integrated short message center for CDMA and GSM networks ZXSC100; and inter-working and sharing gateway of short message center ZXSC100-GW. Short Message Service Center (abbreviated as ZXSC100) provides the function of sending messages in relatively short length between mobile subscribers, or between mobile subscribers and various kinds of short message entities. ZXSC100 mainly comprises short message-signaling gateway (SS7 gateway), service processor, SMPP agent, various kinds of ESMEs and related operation and maintenance system. The functional units employ the modular structure, facilitating capacity and functions expansion. High-speed HUB is employed between various functional modules for communications within ZXSC100. Short message-signaling gateway is developed on the base of the compact SS7 platform of ZXJ10V10.0. The short message-signaling gateway employs fully distributed structure and can be formed by stacking up to 8 modules to realize different system capacities. The diagram is shown below. Short message signaling gateway includes digital trunk unit DTU, central control logic unit CTLU and digital switching unit. As the SS7 processing entity of ZXSC100, the gateway provides SS7 links with such network entities as MSC and HLR, fulfills SS7 functions such as MTP, SCCP, TCAP and MAP, and provides interfaces to the service processor. Playing the role of joint between the short message center and the CDMA network, the short message-signaling gateway offers short message services by exchanging messages with the entities in the CDMA mobile switching network via the standard SS7. Short message signaling gateway adopts compact platform, providing 32 SS7 links for single module and 256 SS7 links for multiple modules. Number of short message signaling gateway can be configured flexibly according to the practical requirements. Service processor adopts server-client mode. The structure diagram is shown below.
Extended short message entities of ZXSC100 series include manual connection platform, automatic connection platform, integrated information platform and SME-Web/E-Mail. Voice Mailbox. Charging center can work as ESME of ZXSC100 as well. Technical Specifications
ZXC10 BSC ZXC10 BSC/PCF 1X¡ªBase Station Controller /Packet Control Function ZXC10 BSC/PCF 1X is developed based on ZXC10 BSC IS95 with the consistent hardware structure. ZXC10 BSC/PCF 1X includes high-speed interconnect router subsystem (HIRS), selector/vocoder bank subsystem (SVPS), call processing subsystem (CPS), base station management subsystem (BSM), and timing subsystem (TS). The relationship of these subsystems is shown below:
Features:
The basic performances of ZXC10 BSC/PCF 1X are:
ZXC10 BTS ZXC10 BTS 1X has the similar hardware structure to ZXC10 BTS IS95 and differs from ZXC10 BTS IS95 only in that it adopts CDMA 20001x channel boards supporting cdma2000 1X RTT standards rather than CDMAOne channel boards. ZXC10 BTS 1X includes time and frequency subsystem (TFS), base-band digital subsystem (BDS) and radio frequency subsystem (RFS), as is shown below:
The basic performances are:
Name of BTS Subsystems: BDS: Base band Digital Subsystem
TFS: Timing Frequency Subsystem
RFS: RF Subsystem
BSS System Working Principle q In ZXC10-BSS system, service/signaling switching between subsystems or modules is not in the traditional circuit switching mode but in the high-speed packet data network switching mode. q The network structure of the ZXC10-BSS system is composed of two levels. § The first level is the HIRS subsystem in BSC, called “B_HIRS”. It’s mainly adopted to provide packet data switching services for connected subsystems or modules. § The second level is Low speed packet data switching network in SVBS, PCFS or BDS, is called “S_HIRS”. Its main function is to provide packet data switching service for each modules in the SVBS, PCFS or BDS subsystems. Performance of BSC Ø Max.number of E1 links between BSC and MSC: 240 Ø Max.number of BTS can be connected with:380 Ø Max. number of selector/vocoder :7200 Ø Max. traffic processing capability:5040 Er (7200 x 0.7) Ø Support soft handoff between BSC Ø 8K、13K QCELP and 8k EVRC vocoder Ø Support packet data service, with a data rate up to 153.6kbps Mechanical Features of BTS BTS includes the following components from top to bottom: · RFE box, · HPA box · Power distribution and module (PSMD/PPM/PSMC) box , · TRX box · BDS (Base band digital subsystem) box In system cooling design, fans and splitter plates are provided between corresponding boxes, so that the whole system has three independent cooling ducts to ensure the normal operating temperature of the equipment. Performance of BTS – Flexible of Configuration: 1,2, 3, 4 Carrier Frequency and ‘Omni, 2, 3 Sector – Maximum radio emission power : 30W – Sensitivity of Radio receiver: -125dbm – Single Rack support 2 Carrier frequency and 3 sectors; Two rack support 4 carrier frequency and 3 sectors; – Support CDMA 800/1900/450MHz frequency configuration – Supports the cell breathing function to ensure the QoS of busy cells – Support the sharing of all sectors channel units with the same carrier frequency Electrical Feature l DC Power Supply Performance Required by the BSC and BTS: Rated value: -48V Allowable voltage fluctuating range: -40V~-57V l While DC power supply is not available, the following AC power supply can be used for the BTS: Rated value: 220V/50Hz Allowable voltage fluctuating range: 176V~264V Allowable frequency variation range: 45Hz~65Hz CDMA forward Traffic Channel: • Used for the transmission of user and signaling information to a specific mobile station during a call. • Maximum number of traffic channels: 64 minus (one Pilot channel + one Sync channel + 7 Paging channel. – This leaves each CDMA frequency with at least 55 traffic channels. – Unused paging channels can provide up to 6 additional channels Pilot Channel: • Used by the mobile station for initial system acquisition • Transmitted constantly by the base station ( at 800 milliseconds scanning) • The same Short PN sequences are shared by all base stations – Each base station is differentiated by a phase offset • Provides tracking of: – Timing reference – Phase reference
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Separation by phase provides for extremely high reuse • Acquisition by mobile stations is enhanced by: – Short duration of Pilot PN sequence – Uncoded nature of pilot signal • Facilitates mobile station-assisted handoffs – Used to identify handoff candidates – Key factor in performing soft handoffs Paging Channels: Used by the base station to transmit system overhead information and mobile station-specific messages. • There is one paging channel per sector per CDMA carrier • The Paging Channel uses Walsh function 1 • Two rates are supported: 9600 and 4800 bps CDMA reverse Traffic Channels: Used when a call is in progress to send: • Voice traffic from the subscriber • Response to commands/queries from the base station • Requests to the base station Supports variable data rate operation for: 8 Kbps vocoder • Rate Set 1 - 9600, 4800, 2400 and 1200 bps 13 Kbps vocoder • Rate Set 2 - 14400, 7200, 3600, 1800 bps Access Channels: • Used by the mobile station to: – Initiate communication with the base station – Respond to Paging Channel messages • Has a fixed data rate of 4800 bps • Each Access Channel is associated with only one Paging Channel • Up to 32 access channels (0-31) are supported per Paging Channel M.Pandian, Divisional Engineer, Installation, BSNL, Salem, Tamilnadu, India. E-Mail: [email protected]; Ph:0427 2452266 and Mobile: 94432 00325
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