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Industrial Training ReportOn

CDMA Network & E1 Troubleshooting

at Tata Teleservices Ltd.

New DelhiPresented by: Divyansh GuptaProject Guide : Mr. J. B. SinghFaculty Supervisor: Prof. Shashikant Patil

2 Tata Teleservices Limited Incorporated in 1996, Tata Teleservices Limited was the pioneer of the CDMA 1x technology in India.

Significant services: CDMA services market-defining wireless mobile broadband(Tata Photon) 2G and 3G Services  

launched significant services CDMA mobile operations in January 2005 under the brand name Tata Indicom,

Market-defining wireless mobile broadband services under the brand name Tata Photon in 2008

2G GSM services under the brand name Tata DOCOMO in 2009

3 CDMA Network of TTSL

8 BSC of TTSL in Delhi and NCR region. BSC 1,2,6,7 are grouped at Concorde and BSC 3,4,5,8 are grouped at VSB (Videsh Sanchar Bhawan)

190-250 BTS are connected to each BSC Each BTS covers an area of approx. 3-4 Km with a

radiating power of 3-5 W.

4 Understanding CDMA Code Division Multiple Access (CDMA) is a channel access method originally

developed for the battlefield. CDMA bands used in telecom:

450 MHz 800 MHz 1900 MHz

In Code Division Multiple Access (CDMA), every communicator will be allocated the entire spectrum all of the time.

Use of wide bandwidth: wider. Advantages including an increased immunity to Interference or Jamming, and multiple user access.

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A few of the benefits of CDMA are

• Superior voice quality • Better reception with less background noise, • Fewer dropped calls, • Enhanced security and greater reliability. • Greater network capacity,

WHY IS CDMA BETTER---------?

6 CDMA spread spectrum

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BTS Rack (on Software)

Sector Cards

BTS Ver. 3606 BTS Ver. 3900

Power Supply Units

E1 Card

s

Data

Call

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BSC rack

9Basic Function of OMC(Operation And Maintenance Centre)

1. Site Monitoring2. Fault Management3. Alarm Monitoring4. Performance Analysis5. Backups6. Analysis Report On Network Outages

Site Monitoring BTS monitoring

Fault Management Fault Management relates to the software as well as

hardware faults in the MSC,BSC and BTS

11 Alarm Monitoring Continuously monitors the alarm reported by all BTSs,

BSCs, MSC and other elements. Since it is not possible to man hundreds of fields locates

sites for these types of issues, so these alarms are also reported to at the OMC from where again these are reported back to the site engineers and technicians for suitable action to be taken to remove them.

The following parameters are monitored –VSWR, RSSI difference, CHPA, and other Sector Down alarms

12Types of alarm

Critical Due to which BTS goes down or

anyservice (CDMA 1x or EV-DO) goes

down. Communication b/w BSC & BTS

Interrupted.

Non-Critical

Due to which service on aparticular sector goes down.

13Alarm Management System Used for live monitoring of the various components of the

RAN. Issues occurring in various entities are reported as alarms

of various levels (minor, major ,critical) , along with the date, time ,location and origination of the alarm.

Alarms are categorized as:- Power System alarms Environment System Alarms Signalling System Alarms Trunk System Alarms Hardware System Alarms Software System Alarms

14Some Important Alarms

PPP Link Fault E1/T1 Loss of Signal (LOS) E1/T1 Alarm Indication

Signal (AIS) Communications Between

BSC and BTS Interrupted E1/T1 BER(Bit error rate)

Threshold Exceeded

Alarms

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Parameters analyzed in KPI

It is a type of performance measurement. Used to evaluate the working efficiency and success of a

particular technological service such as a telecom network. Evaluating the performance of RAN. Separate KPI reports

are generated for both 1x & HSIA.

• TCH CONGESTION RATIO (0.5%)• CS Call Attempts (CS- Circuit Switched)• CS Drop Call Rate 5(%)• CS Call Setup Success Ratio (CSSR) &Access Fail Rate (AFR)(5%)• Hard Block (0.5)• RSSI Difference(Received signal strength indication)

KPI-Key Performance Indicator

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17 Backups

Backups are basically taken for the purpose of redundancy. As the software is loaded for all the hardware installed which is very much prone to errors and bugs, also the network changes are being made continuously ,so it becomes very essential to have a back up, a duplicate copy of all the changes made and that even very up to date. There are two types of Backups:

18 Report On Outages

Covers the total number of sites down through out the day, the time period for which it was down and the main reason for the failure of site.

19E1 Troubleshooting

What is E1 ? The E-carrier system enables the transmission of several (multiplexed)

voice/data channels simultaneously on the same transmission facility A single physical wire pair can be used to carry many simultaneous voice

conversations by time-division multiplexing The line data rate is 2.048 Mbit/s (full duplex, i.e. 2.048 Mbit/s downstream

and 2.048 Mbit/s upstream) which is split into 32 timeslots, each being allocated 8 bits in turn.

20 E1 Circuit Diagram(Status Up)

21 Local(BSC) Loop/Break

Loop

Break

22 BTS End loop/Break

Loop

Break

23 Patching E1 & checking Status

Patching E1 when local issue

Checking E1 using LED

Checking E1 using Loop Cable

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Thank You !