CDMA Presentation

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Presentation Transcript

Slide 1: 

1 Basic knowledge of CDMA MSC Based WLL (BSNL) Compiled by: M.Pandian, Divisional Engineer (Retired) BSNL, Salem-1 E-Mail:

Advantages of CDMA : 

2 Advantages of CDMA Frequency reuse Large coverage High spectrum capacity High Privacy Soft Handoff Good Voice quality (using Voice Coding) Perfect Power Control Smooth migration to 3G

Advantages of CDMA : 

3 Advantages of CDMA Frequency reuse facto is 1; network design and expanding become much easier

Advantages of CDMA : 

4 Advantages of CDMA large coverage almost 2 times than GSM, save money for operator Example:cover 1000 km2: GSM need 200 BTS, CDMA only need 50 BTS Attention: exact result need “Link Budget ”

Advantages of CDMA : 

5 Advantages of CDMA High spectrum capacity: 8--10 times than AMPS, 4—6 times than GSM FDMA---Different user use different frequency TACS、AMPS TDMA---Different user use different time slot of one frequency GSM、DAMPS CDMA---Different user use same frequency at the same time,but with different spreading code

Advantages of CDMA : 

6 Advantages of CDMA High privacy,hard to wiretapping Spread code Information signal TX Demodulated signal RX Spread code Spread signal Each user is below the noise deeply

Advantages of CDMA : 

7 Advantages of CDMA CDMA: “make before break”---soft handoff Other systems: “make after break”---hard handoff Use soft handoff, decrease drop-call rate

Advantages of CDMA : 

8 Advantages of CDMA Good voice quality, use 8k,13K(QCELP,EVRC)voice coding—the best coding method in the world.

Advantages of CDMA : 

9 Advantages of CDMA Perfect Power Control and voice activation make the MS Power low, healthy for humanbody—green mobile phone. Mean Power Max Power GSM: 125mW 2W CDMA: 2mW 200mW

Advantages of CDMA : 

10 Advantages of CDMA 95A  95B Software update Replace MS to get new service 95B  1X Add 1X channel board Software update Replace MS to ge new service 1X  1XEV Add 1XEV channel board Software update Replace MS to get new service inexpensive Technical Scheme: Smooth migration to 3G and the operator’s benefit is protected at the most Almost free inexpensive Economic Scheme:

ZTE’s Activities in CDMA : 

11 ZTE’s Activities in CDMA In 1995, CDMA mobile telecommunication project was started In November, 1999, ZTE signed the “Agreement on CDMA R&D” with Qualcomm In August, 2000, the first field trial was set up. In September, 2000, ZTE presented the first CDMA handset with UIM in the world. In January, 2001, the first cdma2000-1x call was passed through in lab In March, 2001, ZTE cdma2000-1x realized the integrated transmission of voice, data & image. The data rate reach up to 153.6Kbps. The certificates acquired: CDMA 800M ZXC10-MSC/VLR, HLR/AUC,BSC, BTS network access licenses CDMA 800M/1.9G ZXC10-BTS type approval certificates



ZXC10 MSC / VLR : 

13 ZXC10 MSC / VLR ZXC10 MSC/VLR/SSP 1X stands for The CDMA mobile switching center/visitor location register product. 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.

ZXC10 MSC / VLR : 

14 ZXC10 MSC / VLR 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.

ZXC10 MSC / VLR : 

15 ZXC10 MSC / VLR 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.

Technical specifications : 

16 Technical specifications MSC system capacity: 600,000 Max Number of subscribers: 600,000 (64K*64K) Call Processing Capacity for Single Module: 500K BHCA Max Call Processing Capacity: 5,000K BHCA Max Traffic: 21,000Erl Max Number of No.7 signaling links: 640 links VLR System Capacity: 800,000

Slide 17: 

17 Architecture of CDMA system

Slide 18: 

18 MS: Mobile Station BSC: Base Station Controller BTS: Base Transceiver Station MSC: Mobile Switching Center VLR: Visitor Location Register HLR: Home Location Register AUC: Authentication Center OMC: Operation and Maintenance Center MC: Message Center Architecture of CDMA system

Other Terminologies used : 

19 Other Terminologies used PLMN: Public Land Mobile Network ESN: Electronic Serial Number MIN: Mobile Station Identification Number IMSI: International Mobile Subscriber Identification MSIN: Mobile Station Identification Number MCC: Mobile Country Code MNC: Mobile Network Code SID: System Identification NID: Network Identification

Slide 20: 

20 Main components of CDMA MSS (Mobile Switching Sub-system) BSS (Base Station Sub-system) MS (Mobile Station) OMC (Operation and Maintenance Center) Architecture of CDMA system

Slide 21: 

21 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. Architecture of CDMA system

Slide 22: 

22 Function: CDMA switching function 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 ---VLR ---HLR ---AUC 2. Mobile Switching Sub-system Architecture of CDMA system

Slide 23: 

23 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 get data for call handling from 3 databases: VLR/HLR/AUC Architecture of CDMA system 1) Mobile Switching Center(MSC)

Slide 24: 

24 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), user’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 Architecture of CDMA system

Slide 25: 

25 HLR: It is a static database. When a user apply for mobile service, all data about 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. 3) Home Location Register (HLR) Architecture of CDMA system

Slide 26: 

26 4) Authentication Center • Conception: It is an entity to prevent illegal subscribers from accessing CDMA network. It can generate the parameter 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 Architecture of CDMA system

Slide 27: 

27 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. Architecture of CDMA system

ZXC10 BSC : 

28 ZXC10 BSC


29 ZXC10 BSC-FEATURES Two layer high rate packet network structure based on ATM technology Circuit-supporting data service such as asynchronous data, G3 fax. Supporting various types of voice conversion algorithm: QCELP (IS-95), 13kbps Pure Voice (IS-733), EVRC (IS-127) and echo cancellation. Built-in PCF, which supports high rate packet data service primarily based on mobile IP Providing E1/STM-1, which supports A3 and A7 interfaces defined by IOS4.0 and implements the interconnection of BSCs. Providing E1/STM-1, which supports A1, A2 and A5 interfaces defined by IOS4.0 and implements the interconnection of MSCs. Providing Fast Ethernet/ATM., which supports A10 and A11 interfaces defined by IOS4.0 and implements the interconnection of PDSNs.

The basic performances of ZXC10 BSC : 

30 The basic performances of ZXC10 BSC Each BSC owns a HIRS network providing 256 high rate serial ports. Each serial port affords 10Mbps transmission capacity. Each BSC/PCF provides 240 E1 links with MSC maximum. Each BSC/PCF provides 380 E1 inks with BTSs maximum. Each BSC/PCF supports 7200-selectors/ vocoders maximum. Each BSC/PCF has the maximum traffic processing capacity of 5040 Erl. Each BSC/PCF processes 170,000 voice users maximum (based on 0.03Erl/sub) Each BSC/PCF can connect with 380 BTSs (single carrier/single sector) maximum. The BSC/PCF supports packet data services. Each Supports 1260 active PPP connections and 24,000 dormant PPP connections.

ZXC10 BTS : 

31 ZXC10 BTS

The basic performances-BTS : 

32 The basic performances-BTS RAKE receiving, diversity sending, and smart antenna Softer handoff between sectors, soft handoff, and hard handoff Cell breathing, blossoming, wilting, and TPTL High efficient wireless resource management Hot standby for key components Automatic and periodical performance test to ensure reliability All boards can be hot swapped, supporting on line maintenance Module function is relatively independent. Single rack of BTS can accomplish 1,2,3 and 4 carriers, supporting Omni-, 2-sector, 3-sector and 6-sector cell. Supporting capacity expansion in stacking method

The basic performances-BTS : 

33 The basic performances-BTS Supporting 128 forward channels among which 55 channels are traffic channels with data rate of 9.6kbps (Practically 40 x 3 = 120 traffic channels per ‘3sector’ BTS is possible.) All the channel units in a rack form a sharing pool Providing optic fiber interface between base band digital subsystem and radio frequency subsystem. Base station supports indoor modules, outdoor modules and remote RF modules in various packing styles Supporting two types of clock systems: GPS and GLONASS Simultaneously Supporting voice services and mobile IP-based high rate packet data services Providing E1 or STM-1 links between BTS and BSC according to the capacity of BTS

BDS: Base band Digital Subsystem : 

34 BDS: Base band Digital Subsystem CHM: Channel Processing Module CCM: Communication Control Module RFIM: RF Interface Module SAM: Site alarm module BTS_CDSU: BTS-side CDSU module

TFS:Timing Frequency Subsystem : 

35 TFS:Timing Frequency Subsystem GPSTM:GPS Timing Module FDM: Frequency Distribution Module TCM: Timing Control Module

RFS:RF Subsystem : 

36 RFS:RF Subsystem TRX: RF Transceiver HPA: High Power Amplifier RFE: RF Front End RFCM: RF Control Module BTM: Base station testing module

CDMA Forward Traffic Channels : 

37 CDMA Forward Traffic Channels 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, and 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 : 

38 Pilot Channel Used by the mobile station for initial system acquisition Transmitted constantly by the base station 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 Separation by phase provides for extremely high reusewithin one CDMA channel frequency 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

Sync Message Parameters : 

39 Sync Message Parameters Message Type (MSG_TYPE) – Identifies this message and determines its structure (set to the fixed value of ‘00000001’) Protocol Revision Level (P_REV) – Shall be set to ‘00000001’ Minimum Protocol Revision Level (MIN_P_REV) – 8-bit unsigned integer identifying the minimum protocol revision level required to operate on the system. Only mobile stations that support revision numbers greater than or equal to this field can access the system. System ID (SID) – 16-bit unsigned integer identifying the system Network ID (NID) – 16-bit unsigned integer identifying the network within the system (defined by the owner of the SID) Pilot PN Sequence Offset Index (PILOT_PN) – Set to the pilot PN offset for the base station (in units of 64 chips), assigned by the network planner Long Code State (LC_STATE) – Provides the mobile station with the base station long code state at the time given by the SYS_TIME field, generated dynamically System Time (SYS_TIME) – GPS system-wide time as 320 ms after the end of the last superframe containing any part of this message, minus the pilot PN offset, in units of 80 ms, generated dynamically

Sync Channel Message (cont.) : 

40 Sync Channel Message (cont.) Leap Seconds (LP_SEC) – Number of leap seconds that have occurred since the start of system time (January 6, 1980 at 00:00:00 hours) as given in the SYS_TIME field, generated dynamically Local Time Offset (LTM_OFF) – Two’s complement offset of local time from system time in units of 30 minutes, generated dynamically Current local = SYS_TIME – LP_SEC + LTM_OFF Daylight savings time indicator (DAYLT) – Determined by the network planner 1 if daylight savings in effect in this base station 0 otherwise Paging Channel Data Rate (PRAT) – The data rate of the paging channel for this system, determined by the network planner 00 if 9600 bps 01 if 4800 bps CDMA Frequency Assignment (CDMA_FREQ)

Paging Channels : 

41 Paging Channels 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 : 

42 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 : 

43 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

CDMA MS Call Processing : 

44 CDMA MS Call Processing

Field Problems : 

45 Field Problems ZTE Instruments reading the Primary Channel 42 and 83 in the same instrument; example felt at Namakkal and Attur. Cell Demarcation: Subscriber of one SDCA has to work in the BTS located in the other SDCA with the dominated signal. Example at Kandhampayam and Puduchathiram. This has been experimented at Madurai MSC and to be tried at Pondichery MSC also.

Slide 46: 

46 Thanks for listening Contact me at 9443200325 04272452266

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