On the base of telegraph

2. Investigating RF Signal Statistics
using TEMS
for Quality and Coverage in GSM
FINAL YEAR PROJECT
TELECOMMUNICATION ENGINEERING
BATCH - S06

3.  Presented By :
Allah Rakha Bizenjo BETL/S06/0123
 Supervisor :
Dr. Rashid Hussain
 Co-Supervisor :
Engr. Sheraz Arif

4. Table of Content
 Acknowledgement
 Objective
 GSM
 GSM History
 GSM System Architecture
 GSM Specifications
 Introduction to TEMS
 Subjects to Investigate
 Drive Testing

5. Table of Contents cont….
 TEMS Information
 Versions of TEMS
 My Goals and Achievements
 Coverage Problems
 Quality Problems

6. ACKNOWLEDGEMENT
 First of all, I would like to thank AlmightyFirst of all, I would like to thank Almighty
AllahAllah for his countless Blessings.for his countless Blessings.
 My parents for supporting me inMy parents for supporting me in
developing My career.developing My career.
 And Supervisor’s for their all time support.And Supervisor’s for their all time support.

7. Objective
My project goal is to mearsure and investigate
the transmitted RF Signal Statistics.
 The usefull tool for this Investigation is TEMS
(8.0.3) version.
 To measure the quality of received signal
through walk and drive tests.

8. What is GSM ?
Global System for Mobile (GSM) is a second
generation cellular standard developed to
cater voice services and data delivery using
digital modulation also known as (Public Land
Mobile Network), or PLMN, and due to the
frequency re-use pattern GSM is more
efficient.

9. GSM: History
 Developed by Group Spéciale Mobile (founded 1982)
which was an initiative of CEPT ( Conference of
European Post and Telecommunication )
 • Aim : to replace the incompatible analog system
 • Presently the responsibility of GSM standardization
resides with special mobile group under ETSI
( European telecommunication Standards Institute )

10. GSM System Architecture
BSC
BSC
MSC
MS
MS
MS BTS
BTS
BTS
GMSC
EIR
AUC
HLR
VLR
PSTN
ISDN
PDN

11. GSM System Architecture
 Mobile Station (MS)
Mobile Equipment (ME)
Subscriber Identity Module (SIM)
 Base Station Subsystem (BSS)
Base Transceiver Station (BTS)
Base Station Controller (BSC)
 Network Switching Subsystem(NSS)
Mobile Switching Center (MSC)
Home Location Register (HLR)
Visitor Location Register (VLR)
Authentication Center (AUC)
Equipment Identity Register (EIR)

12. System Architecture
Mobile Station (MS)
The Mobile Station is made up of two entities:
1. Mobile Equipment (ME)
2. Subscriber Identity Module (SIM)

13. System Architecture
Mobile Station (MS)
Mobile Equipment (ME)
 Portable,vehicle mounted, hand held device
 Uniquely identified by an IMEI (International Mobile
Equipment Identity)
 Voice and data transmission
 Monitoring power and signal quality of surrounding
cells for optimum handover
 Power level : 0.8W – 20 W
 160 character long SMS.

14. System Architecture
Mobile Station (MS) contd…
Subscriber Identity Module (SIM)
The SIM card contains the International Mobile
Subscriber Identity (IMSI) used to identify the
subscriber to the system, a secret key for
authentication, and other information. The IMEI and
the IMSI are independent, thereby allowing personal
mobility. The SIM card may be protected against
unauthorized use by a password or personal identity
number

15. System Architecture
Base Station Subsystem (BSS)
Base Station Subsystem is composed of two parts that
communicate across the standardized Abis interface
allowing operation between components made by different
suppliers
• Base Transceiver Station (BTS)
• Base Station Controller (BSC)

16. System Architecture
Base Station Subsystem (BSS)
Base Transceiver Station (BTS):
 Encodes,encrypts,multiplexes,modulates and feeds
the RF signals to the antenna.
 Frequency hopping
 Communicates with Mobile station and BSC
 Consists of Transceivers (TRX) units
 RBS (Radio Base Station)
 BBS (Battery Base Station)

17. System Architecture
Base Station Subsystem (BSS)
Base Station Controller (BSC)
 Manages Radio resources for BTS
 Assigns Frequency and time slots for all MS’s in its
area
 Handles call set up
 Transcoding and rate adaptation functionality
 Handover for each MS
 Radio Power control
 It communicates with MSC and BTS

18. System Architecture
Network Switching Subsystem(NSS)
Mobile Switching Center (MSC)
 Heart of the network
 Manages communication between GSM and other networks
 Call setup function and basic switching
 Call routing
 Billing information and collection
 Mobility management
- Registration
- Location Updating
- Inter BSS and inter MSC call handoff
 MSC does gateway function while its customer roams to other
network by using HLR/VLR.

19. System Architecture
Network Switching Subsystem
 Home Location Registers (HLR)
- permanent database about mobile subscribers in a large service
area(generally one per GSM network operator)
- database contains IMSI,MSISDN,prepaid/postpaid,roaming
restrictions,supplementary services.
 Visitor Location Registers (VLR)
Temporary database which updates whenever new MS enters its
area, by HLR database
- Controls those mobiles roaming in its area
- Reduces number of queries to HLR
- Database contains IMSI,TMSI,MSISDN,MSRN,Location
Area,authentication key

20. System Architecture
Network Switching Subsystem
 Authentication Center (AUC)
- Protects against intruders in air interface
- Maintains authentication keys and algorithms and
provides security triplets
- Generally associated with HLR
 Equipment Identity Register (EIR)
- Database that is used to track handsets using the
IMEI (International Mobile Equipment Identity)
- Made up of three sub-classes: The White List, The
Black List and the Gray List
- Only one EIR per PLMN

21. GSM Specifications
RF Spectrum
 GSM 900
Mobile to BTS (uplink): 890-915 Mhz
BTS to Mobile(downlink):935-960 Mhz
Bandwidth : 2.25 Mhz
 GSM 1800
Mobile to BTS (uplink): 1710-1785 Mhz
BTS to Mobile(downlink) 1805-1880 Mhz
Bandwidth : 2.75 Mhz

22. Introduction to TEMS
What is TEMS..?
TEMS = Test Mobile System
Product byProduct by
 Solution Tools for Wireless Network to Plan, optimized,
and expand their systems.
 A Test tool use to read and control information sent over the air
 Interface between the base station and the mobile station in
GSM system. It can also used for radio coverage measurement.

23. TEMS cont…
DDrive Test
Testing the network in particular area to giveTesting the network in particular area to give
the real picture of the network’s performance onthe real picture of the network’s performance on
the field, with a certain tools.the field, with a certain tools.
There are eight (08) versions of TEMS, while weThere are eight (08) versions of TEMS, while we
usedused TEMS (8.0.3) version.

24. Subjects to Investigate
 Non–working sites/sectors or TRXs
 In–active Radio network features like frequency hopping
 Disabled GPRS
 Overshooting sites – coverage overlaps
 Coverage holes
 C/I, C/A analysis
 High Interference Spots
 Drop Calls
 Capacity Problems
 Other Interference Sources
 Equipment Performance
 Faulty Installations

25. DRIVE TESTING
Drive testing is the most common and maybe the best
way to analyze Network performance by means of:
 Coverage evaluation
 System availability
 Network capacity
 Network retainibility and call quality
Although it gives idea only on downlink side of the
process, it provides huge perspective to the service
provider about what’s happening with a subscriber
point of view.

26. TEMS Information
The information provided by TEMS is
displayed in status windows. This information
includes
 Cell identity
 Base station identity code
 BCCH carrier ARFCN
 Mobile country code
 Mobile network code and the
 location area code, of the serving cell

27. Versions of TEMS
 TEMS Classic/98TEMS Classic/98 : SH888; post process with 3rd-party-s/w: SH888; post process with 3rd-party-s/w
 TEMS 2TEMS 2 : R230; post process with 3rd-party-s/w: R230; post process with 3rd-party-s/w
 TEMS 3TEMS 3 : R520; post process with 3rd-party-s/w: R520; post process with 3rd-party-s/w
 TEMS 4TEMS 4 : T68; export from TEMS: T68; export from TEMS
 TEMS 5TEMS 5 : T610; export from TEMS: T610; export from TEMS
 TEMS 6TEMS 6 : various handset; data collection & route: various handset; data collection & route
analysisanalysis
 TEMS 7TEMS 7 : various handset; data collection & route: various handset; data collection & route
analysianalysi
ss

28. My Goals and
Achievements:
Analysis Of Log Files
Coverage Problems:
 Low Signal Level
 Fast Moving Mobile
 Sudden Decrease of Signal Level
 Drop Call due to Bad Coverage
 RX Levels of Many Cells are Almost the Same

29. Low Signal Level
Low Signal Level: In areas where there are few sites and too many different types
of terrain structures like hills or obstacles those stopping the line of sight to the
broadcasting signal, there might be a lot of coverage holes or places with
insufficient signal level.
Low signal
level

30. Fast Moving Mobile
Fast Moving Mobile Effect: When MS moves very fast, the tester will see a lot of
handovers and sudden changes on signal levels. This case might happen when
the MS user is driving fast on the highway.
HO’s due to
moving fast

31. Sudden Decrease on Signal Level
Sudden Decrease on Signal Level (Tunnel Effect): This will result in
excessive number of handovers.
Curve Formation due to Tunnel
Effect Causing Sudden Level
Decrease and Ping Pong
Handovers

32. Drop Call due to Bad Coverage
Drop Call due to Bad Coverage: Call is dropped because of poor
coverage. The signal level goes down below the minimum signal
level that system could carry on.
Bad coverage

33. RX Levels of Many Cells are Almost the
Same
Signal Strength of All the neighbors are almost the same: This
shows the network needs big optimization work because there are too many
cells having overlapping coverage.
Too many
overlapping
cells

34. My Goals and Achievements cont…….
Analysis Of Log Files
Quality Problems
Dropped calls due to bad quality
 Call releases due to bad quality
 Handover failures
 Intra–cell handover,
 RXQUAL distribution

35. Bad Quality due to Signal Strength, FER is Bad
Bad Quality due to Signal Strength – Bad FER: As the signal
strength drops down, the quality of the call becomes worse being
effected by interference and/ or fading.
Bad RxLev
Bad RXQual
Bad FER

36. Bad Quality due to Signal Strength, FER is
OK
Bad Quality due to Signal Strength, FER is OK: The difference of this case from
the previous is only the difference in FER. Signal strength is also bad in this, but
FER is still fine which means there is no obvious interference in the area.
RX Quality is bad
FER is fine

37. Handover Failure
Reasons for handover failure could be unavailable time slots because of
high traffic, congestion, low signal strength or bad quality. If handover
attempt fails, MS tries to return to old channel. If it can not, call drops.
HO attempted
was failed

38. General Reasons for Drop Calls are as
follows:
 Drop Call due to Low Signal Strength
 Drop Call due to Missing Neighbor
 Drop Call due to Bad RX Quality
 Drop Call due to Not–happening Handover
 Drop Call due to Interference
 Radio Failures
 Transcoder Failures.
 BTS failures

39. Solutions to Low Level Problems
Possible solution ways can be listed as below:
 New Site Proposal
 Sector Addition
 Repeater
 Site Configuration Change (Antenna Type,height,tilt
 Loss or Attenuation Check (Feeders,Connectors
,jumpers)

40. References:
 Ericsson.com/tems
 Through drive tests
 Telenor GSM
 TEMS 8.0.3 version
 Wireless Comm by Rappaport

41. THANK YOU..