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1
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.
5
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
7
BTS Rack (on Software)
Sector Cards
BTS Ver. 3606 BTS Ver. 3900
Power Supply Units
E1 Card
s
Data
Call
8
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
15
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
16
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
24
Thank You !