LTE DRIVE TEST PARAMETERS

RSRP :- Reference signal receive power.

RSRP (dBm) = RSSI (dBm) -10*log (12*N)

where RSSI = Received Signal Strength Indicator
N: number of RBs across the RSSI is measured and depends on
the BW
Significance :
RSRP is the most basic of the UE physical layer measurements and is the
linear average power (in watts) of the downlink reference signals (RS) across
the channel bandwidth for the Resource elements that carry cell specific
Reference Signals.
Knowledge of absolute RSRP provides the UE with essential information
about the strength of cells from which path loss can be calculated and used
in the algorithms for determining the optimum power settings for operating
the network. Reference signal receive power is used both in idle and
connected states
Range :- -44 to -140 dBm

RSRP term is used for coverage same as RSCP in 3G

RSRQ :Reference signal receive quality
RSRQ = RSRP / (RSSI / N)
N is the number of resource blocks over which the RSSI is measured
RSSI is wide band power, including intra cell power, interference and noise.
Significance :It provides the Indication of Signal Quality . Measuring RSRQ becomes
particularly important near the cell edge when decisions need to be made,
regardless of absolute RSRP, to perform a handover to the next cell.
Reference signal receive quality is used only during connected states
Range :- -3 to -19.5 dB
RSRQ term is used for Quality same as Ec/No in 3G.
* SINR :-Signal to Noise Ratio.
SINR = S / I + N
S -- Average Received Signal Power
I -- Average Interference power
N -- Noise Power
Significance : Is a way to measure the Quality of LTE Wireless Connections.
As the energy of signal fades with distance i.e Path Loss due to
environmental parameters ( e.g. background noise , interfering strength of
other simultaneous transmission)
RSSI :- Received Signal Strength Indicator.

RSSI = wideband power = noise + serving cell power +

interference power

RSSI=12*N*RSRP
RSSI per resource block is measured over 12 resource elements.
N: number of RBs across the RSSI is measured and depends on the BW

Based on the above:

RSRP (dBm) = RSSI (dBm) -10*log (12*N)
Significance : RSRP Is the parameter represents the entire
received power including the wanted power from the serving cell
as well as all the co channel power & other sources of noise
CQI :- Channel Quality Indicator
Range :- 1 to 15
Significance:
CQI is a measurement of the communication quality of wireless channels
i.e. it indicates the downlink mobile radio channel quality as experienced by
the UE .CQI can be a value representing a measure of channel quality for a
given channel. Typically, a high value CQI is indicative of a channel with high
quality and vice versa.
CQI is measured in the Dedicated mode only.
CQI depends on the RF conditions.
Better the CQI better the throughput will get and vice versa.
PCI :- Physical Cell Id
Range :- 0 to 503
Significance - PCI used to identify the cell & is used to transmit the data
PCI = PSS + 3*SSS
PSS is Primary Synchronization Signal ( Identifies Cell Id ).
PSS value can be 0, 1 & 2
SSS is Secondary Synchronization Signal ( identifies Cell Id group).
SSS value can be 0 to 167.
BLER :- Block Error Rate
Block Error Ratio is defined as the ratio of the number of erroneous
blocks received to the total number of blocks transmitted
Significance: A simple method by which a UE can choose an
appropriate CQI value could be based on a set of Block Error Rate (BLER)
thresholds . The UE would report the CQI value corresponding to the
Modulation Coding Schemes that ensures BLER 10% based on the
measured received signal quality
BLER is Calculated using Cyclic Redundancy error Checking method
High BLER leads to loss of Peak rates & efficiency
BLER threshold should be low i.e. 10%

Downlink Throughput
- n E-UTRAN may use a maximum of 2 Tx antennas at the ENodeB and 2 Rx
antennas at the UE ( MIMO ).
Significance: Target for averaged user throughput per MHz, 3 to 4
times
Release 6 HSDPA i.e Higher user throughput as compared to 3G ( Over 300
Mbps downlink as compared to 14 Mbps in UMTS)
The supported user throughput should scale with the spectrum bandwidth.
Uplink Throughput
-I n E-UTRAN uses a maximum of a single Tx antenna at the UE and 2 Rx
antennas at the E Node B.
- Greater user throughput should be achievable using multiple Tx
antennas at the UE ( MIMO )
Significance: Target for averaged user throughput per MHz, 2 to 3
times Release 6 Enhanced Uplink i.e Higher user throughput as
compared to 3G (Over 50 Mbps Uplink as compared to 5.76 Mbps
in UMTS).The user throughput should scale with the spectrum
bandwidth provided that the maximum transmit power is also
scaled.
Phone-Based Drive Test for LTE
Phone-based drive test systems are useful for evaluating basic network
performance and are essential to characterizing the end-user experience
while using the network. Phone-based systems address the need to verify
network settings such as cell selection and re-selection boundaries and to
measure the voice and data application performance in the live network.
Most modern mobile phones chipsets have engineering measurement
capabilities built into them, which were used during the mobile phones
design process.
These same parameters are exploited in drive test software to provide new
value to the RF engineers rolling out the final network.
With radio resource management taking place in the eNB, suitably
instrumented phones can be used to monitor the performance of the
physical layer including modulation schemes, access procedures,
synchronization, and power control.
The same types of parameters are measured for LTE as for other cellular
technologies. Beyond the essential protocol log, which provides visibility of
the fundamental interaction with the network, the initial focus is on RF
coverage and quality. Figure 3 identifies the main measurements that are
made. In LTE, these equate to reference signal received power (RSRP) and
reference signal received quality (RSRQ), which are measures of the strength
and quality of reference signals. These two results are the major components

of network-based decisions to keep a UE on its current cell or hand it over to

an adjacent cell.
Additional measurements used to assess the link quality include call quality
index (CQI) and block error rates (BLER). While RSRQ is the 3rd Generation
Partnership Project (3GPP)-defined measure of signal-to-noise ratio (S/N),
which all mobiles must make and report, many LTE UEs are also making
custom carrier-to-noise ratio (C/N) measurements, which they use internally
to assess channel quality. These additional carrier-to-interference (C/I)
measurements are not reported back to the network, but they are available
within the drive test logs and can be used by RF engineering teams to get
extra insight as to how
the mobiles perceive the RF environment.
Instrumented phones can also report the measured channel state
information (CQI, pre-matrix indicator [PMI], and rank indicator [RI]) and
hybrid automatic repeat request (HARQ) statistics. The number of resource
blocks assigned to a device at a particular time, together with the
modulation and coding scheme applied, can be used to evaluate the eNB
scheduler performance. These types of tests are of particular interest during
early stages of deployment of a new network but also must be monitored as
network loading increases and true end-user traffic patterns establish
One of the most interesting LTE network features to RF optimization
engineers is the impact that multiple input multiple output (MIMO) with
spatial multiplexing and antenna diversity brings to the end-user
performance. Drive-test-enabled devices can log the current rank, number of
transmit and receive paths in active use, together with the reported
availability of antennas. They can also individually report the signal strength
and quality from each of the devices antennas. This information can be
correlated with
the measured data application performance to establish the impact MIMO
has on network performance.
Because full MIMO is a feedback system, an instrumented mobile that is part
of the active channel is the only way to evaluate the true impact that this
technology can make.
As LTE networks are deployed alongside existing cellular networks, cellular
operators are particularly interested in the efficient use of each network
resource and the transition between the network technologies. Drive testing
is used extensively to monitor the handover points between LTE and legacy
technologies. The signal strength, quality, cell ID, and neighbor information
both before and after a handover are analyzed and optimized. The length of
time it takes to complete an initiated handover, success rates, and the enduser data-interruption time (during the actual transition between
technologies) are key performance indicators that are closely monitored.

End-user data throughput performance and latency are the two key
measures of a networks optimization. If the network is not achieving the
expected data performance, it is important to be able to analyze the
signaling performance and settings at each signaling layer, including the
radio resource control (RRC), radio link control (RLC), and media access
control (MAC). Monitoring the resources allocated to a UE together with the
measured network conditions, available neighbor cells. and power levels will
allow troubleshooting and optimization of network settings

Header (computing)
From Wikipedia, the free encyclopedia
In information technology, header refers to supplemental data placed at the
beginning of a block of data being stored or transmitted. In data
transmission, the data following the header are sometimes called the
payload or body.
It is vital that header composition follow a clear and unambiguous
specification or format, to allow for parsing.
Examples

E-mail header: The text (body) is preceded by header lines indicating

sender, recipient, subject, sending time stamp, receiving time stamps of all
intermediate and the final mail transfer agents, and much more. See RFC
5322 for details. Similar headers are used in Usenet (NNTP) messages, and
HTTP headers.


In a data packet sent via the Internet, the data (payload) are preceded
by header information such as the sender's and the recipient's IP addresses,
the protocol governing the format of the payload and several other formats.
The header's format is specified in the Internet Protocol.

In data packets sent by wireless communication, and in sectors of data

stored on magnetic media, typically the header begins with a syncword to
allow the receiver to adapt to analog amplitude and speed variations and for
frame synchronization.

In graphics file formats, the header might give information about an

image's size, resolution, number of colors, and the like.

In Archive file formats, the file header might serve as a fingerprint or

signature to identify the specific file format and corresponding software
utility.

In some programming languages (for example C and C++) the

functions are declared in header files.

GSM Interview Question -Answer

1. What is the function of SDCCH & SACCH?
Ans. (a) SDCCH---- Slow Dedicated Control Channel.
Function:
a)
Location updates
b)
SMS
c)
Ciphering Initiation
d)
Equipment Validation
e)
Subscriber authentation
f)
Call set up signaling
(b) SACCH---Slow Associated Control Channel.
Function:
(a)
Timing advance data
(b)
Transmit power control
(c)
transmission of signaling data
(d)
radio link supervision measurements
2. What are the reasons for Hand Overs?
(Ans) . (a) Signal Strength (RX LEVEL)
(b) Signal Quality (RX Qual)
(c) Power Budget
(d) Timing Advance.

(e) Interference
3. What are the shortcomings in handovers?
a) Call Dropping.
b) Ping- Pong handover
c) Far- Away cell effect
4. What is intelligent hand over?
Ans a) Fuzzy logic
b) Neutral networks
5. What are internal & external hand over?
Ans
1) INTERNAL HANDOVER
a) ( INTER BTS): Transfer between two channels (time slot) in same cell.
b) ( INTRA BSC ( BTS BTS):
1 . transfer between BTS under control of same Bsc
2 . Measuring the quality of radio connection
3 . Power levels
2). EXTERNAL HANDOVER.
a) INTER BSC (BSC_ BSC):
1. Transfer between BTS under the control of diff BSC
2. BSC TO BSC
3 . NSS to attends the hand over
4. MSC controls.
b) INTER MSC ( MSC- MSC) ----1. transfer between cell under the control
of diff MSC
6.What is the frequency Hopping?
It is defined as sequential change of carrier frequency on the radio
link between mobile & base station.
Two types of freq hopping: 1. Base band freq hopping.
2. synthesized frequency hopping.
7. Explain the major difference between BBH & SFH?
Ans
In BBH the number of hopping freq is same as number of TRX.
In SFH the number of Hoping freq can be in the range of 1 to 63.
8. what are the advantages of Frequency Hopping?
1. Frequency Diversity
2. Interference Averaging
3. increase the network capacity

9. How in frequency hopping there is enhancement of network capacity?

Freq hopping implement will enable more aggressive freq reuse pattern,
that leads to better spectrum efficiency.
It can add more transceiver in the existing sites , while maintaing the net
work quality/
Freq hopping compressing the available spectrum to make room for extra
capacity
.
10. Define the freq. hopping parameters?
Frequency Hopping Parameters
GSM defines the following set of parameters:
- Mobile Allocation (MA): Set of frequencies the mobile is allowed to
hop over. Maximum of 63 frequencies can be defined in the MA list.
- Hopping Sequence Number (HSN): Determines the hopping order
used in the cell. It is possible to assign 64 different HSNs. Setting
HSN = 0 provides cyclic hopping sequence and HSN = 1 to 63 provide
various pseudo-random hopping sequences.
- Mobile Allocation Index Offset (MAIO): Determines inside the
hopping sequence, which frequency the mobile starts do transmit on.
The value of MAIO ranges between 0 to (N-1) where N is the number
of frequencies defined in the MA list. Presently MAIO is set on per
carrier basis.
Motorola has defined an additional parameter, FHI.
Hopping Indicator (FHI): Defines a hopping system, made up by an
associated set of frequencies (MA) to hop over and sequence of
hopping (HSN). The value of FHI varies between 0 to 3. It is possible
to define all 4 FHIs in a single cell.
Motorola system allows to define the hopping system on a per
timeslot basis. So different hopping configurations are allowed for
different timeslots. This is very useful for interference averaging and
to randomize the distribution of errors.
11. What are the effects of freq hopping?
(Ans)
1 Handovers:
2 Call setup:
3 Frame Erasure Rate (FER):
12 .Explain in brief what is FER.
FER= Number of erased blocks\ total no of blocks *100
It is the right measure of voice quality.
FER is performed on speech& signaling frames

FER: 0 to 4%,
GOOD.
4 to 15% , slightly degraded
> than 15%, useless
13. What happens when speech frames discarded in FER?
System will interpolate.
14. What happens when signaling frames discarded in FER?
MS is instructed to resend.
15. What is TCH_ TCH Interference? How it is measured.
When TCH carries are reused that leads to co-channel interference.
When TCH carrier have call activity.
This is measured by delta measurement: 1. BCCH carries are diff
2. TCH carriers of both cell 1& cell2 are
same AFRCN TCH
16. Define the terms?
BER:The number of erroneous bits received
Total no of bits received.
RBER: 1. Residual bit error rate
2. It is performed on demodulated speech frames that are not mark
corrupt
*BFI : Bad frame indication.
17. Explain the parameters in TEMS POCKET mobile.
L
BC
BS
RXLEV
L
TC
TS
TX
C/I
RQ
FE
TA

DSC

CHM

MCC

RH
MNC

CiMd
LAC

RA

1.
2.
3.
4.
5.

CI

Llcell BCCH ARFCN

 L1. Logical channel.----- BCCH

L2. Logical channel ----- TCH
BC-- serving cell BCCH AFRCN.
BS-- base station identity code.
RXLEV- recieved signal strength
TC- TS -

traffic channel
time slot number.

TX - transmit power
C/I -- Carrier to interference ratio in db
RQ -- Receive bit error rate
FE frame erasure rate.
TA -- Timing advance
CHM --C hannel Mode
RH -- cell reselction Hystresis
CiMdCiphering mode
RAC Routing area code.
LACLocation area code.
18. Explain the analysis behind RX Qual.?
RX Qual is the basic measure. It reflects the average BER over the certain
period of time (0.5s)
RX QUAL done over 104 TDMA frames.
Limitation of RXQUAL: 1. The distributions of bit error over time.
2. Frame erasure
3. Hand over.
19. What are type of interference occur?
1. Co- channel interference.
2. Adj-channel interference.
3. Near end- Far end interference.

20. What is ERLANG?

Unit of telephone traffic intensity is called Erlang.
One ERLANG is one channel occupied continuously for one hour.
1E = 64Kbps.
21. what do you mean by GOS?
It is the probabity of having a call blocked during busiest hour.
Ex GOS=0.05 means one call in 20 will be blocked call during busiest hour
because of insufficient capacity.
22. What are the technique GSM offers which combat Multipath fading?
Equalization
Diversity
Freq Hopping
Interleaving
Channel coding
23. What are control &traffic channels?

CONTROL CHANNEL.:1. BCH

2. CCCH
3. DCCH.

TRAFFIC CHANNEL: Half rate

Full rate
EFR == Enhanced full
rate.

24. What are BCH, CCH, DCCH channels?

BCH-- 1. BCCH
2 .FCCH
3. SCH

CCCH. --- 1.PCH

2. AGCH
3. RACH

DCCH----

Normal Burst
Frequency Correction Burst
Synchronization Burst.

1.SDCCH.
2. SACCH
3. FACCH
25. What are types of bursts?


Dummy Burst

Access Burst.
26. What is adjacent channel separation in GSM?

Urban Environment-------- 200khz

Sub Urban Environment ---- 400khz

Open environment ----- 800khz

27. What is the watt to dBm conversions?

Power in dBm = 10 log( watts *100)

0 dBm= 1mili watt

1watt = 30dbm

28. What are the optimizations you have done during

Drive Test?

What are samples in gsm?

Which modulation take place in GSM

In one TRU how many frames are there?

What is the value RXLEV of neighboring cell?

What do you mean by VAD?

What is BFI, where it is use?

2929. Define the hopping parameters in detail?

The MA is a list of hopping frequencies transmitted to a mobile every time it
is assigned to a hopping physical channel. The MA-list is a subset of the CA
list. The MA-list is automatically generated if the baseband hopping is used.
If the network utilises the RF hopping, the MA-lists have to be generated for
each cell by the network planner. The MA-list is able to point to 64 of the
frequencies defined in the CA list. However, the BCCH frequency is also
included in the CA list, so the practical maximum number of frequencies in
the MA-list is 63. The frequencies in the MA-list are required to be in
increasing order because of the type of signaling used to transfer the MA-list.
1.1
Hopping Sequence Number
The Hopping Sequence Number (HSN) indicates which hopping sequence of
the 64 available is selected. The hopping sequence determines the order in
which the frequencies in the MA-list are to be used. The HSNs 1 - 63 are
pseudo random sequences used in the random hopping while the HSN 0 is
reserved for a sequential sequence used in the cyclic hopping. The hopping
sequence algorithm takes HSN and FN as an input and the output of the
hopping sequence generation is a Mobile Allocation Index (MAI) which is a
number ranging from 0 to the number of frequencies in the MA-list
subtracted by one. The HSN is a cell specific parameter. For the baseband

hopping two HSNs exists. The zero time slots in a BB hopping cell use the
HSN1 and the rest of the time slots follow the HSN2 as presented in Error!
Reference source not found.. All the time slots in RF hopping cell follow the
HSN1 as presented in Error! Reference source not found..
1.2
Mobile Allocation Index Offset
When there is more than one TRX in the BTS using the same MA-list the
Mobile Allocation Index Offset (MAIO) is used to ensure that each TRX uses
always an unique frequency. Each hopping TRX is allocated a different MAIO.
MAIO is added to MAI when the frequency to be used is determined from the
MA-list. Example of the hopping sequence generation is presented in Error!
Reference source not found.. MAIO and HSN are transmitted to a mobile
together with the MA-list. In Nokia solution the MAIOoffset is a cell specific
parameter defining the MAIOTRX for the first hopping TRX in a cell. The MAIOs
for the other hopping TRXs are automatically allocated according to the
MAIOstep -parameter introduced in the following section.
30. What is the effect of frequency hopping in RXQual?
Frequency hopping causes some changes in the RXQUAL distribution. Also,
there are some differences in a way the RXQUAL distribution should be
interpreted.
The Frame Erasure Ratio (FER) is a ratio of discarded speech frames
compared to all the received speech frames. A speech frame is generally
discarded if after the decoding and error correction process any of the
category 1a bits is found to be changed based on the three parity bits
following them in a speech frame.
FER is a measure of how successfully the speech frame was received
after the error correction process and it is thus a better indication of the
subjective speech quality compared to the RXQUAL which gives an estimate
of the link quality in terms of BER. The RXQUAL doesnt indicate how the bit
errors were distributed in a speech frame. The bit error distribution affects
the ability of the channel decoding to correct the errors.
The following table gives an idea of the correlation between RXQUAL and FER
and between subjective speech quality and different FER classes.
31. What is the relation link between RXQUAL& FER?
Table 1. RXQUAL vs. FER comparison according to the laboratory tests.

The relation of downlink FER and RXQUAL was measured during a FH trial.
The relation is clearly different in the hopping case compared to the nonhopping case. The distributions of FER in each RXQUAL class are presented in
Error! Reference source not found. and Error! Reference source not found..
One clear observation can be made; in the non-hopping case there are
significant amount of samples indicating deteriorated quality (FER>10%) in
RXQUAL class 5 while in the hopping case the significant quality
deterioration (FER>10%) happens in RXQUAL class 6. Thus, it may be
concluded that in the frequency hopping networks significant quality
deterioration starts at RXQUAL class 6 while in non-hopping network this
happens at RXQUAL class 5.
This improvement of FER means that the higher RXQUAL values may be
allowed in a frequency hopping network. RXQUAL thresholds are used in the
handover and power control decisions. Because of the improvement in the
relative reception performance on the RXQUAL classes 4-6, the RXQUAL
thresholds affecting handover and power control decisions should be set
higher in a network using frequency hopping network. In a frequency
hopping network RXQUAL classes 0-5 are indicating good quality.
Typically, the share of the RXQUAL classes 6 and 7 may increase after FH is
switched on, even if no other changes have been made. This may seem to be
surprising since it is expected that frequency hopping improves the network
quality. However, in most cases the quality is actually improved, but the
improvement is more visible in the call success ratio. The improved tolerance
against interference and low field strength in FH network means that it is less
likely that the decoding of SACCH frames fails causing increment in the radio
link timeout counter. Thus, it is less likely that a call is dropped because of
the radio link timeout. Instead, the calls generating high RXQUAL samples
tend to stay on. This may lead to increase in the share of RXQUAL 6-7.
However, at the same time the call success rate is significantly improved.

In the Error! Reference source not found., there are presented some trial
results of a DL RXQUAL distribution with different frequency allocation reuse
patterns. As can be seen from the figures, the tighter the reuse becomes, the
less samples fall in quality class 0 and more samples fall in quality classes 16. Theres bigger difference in downlink than in uplink direction.
This difference is a consequence of interference and frequency diversities
that affect the frequency hopping network. Because of these effects, the
interference or low signal strength tend to occur randomly, while in a nonhopping network it is probable that interference or low field strength will
affect several consecutive bursts making it harder for the error correction to
actually correct errors. The successful error correction leads to less erased
frames and thus improves the FER.
32. What do you understand by idle channel measurement?

When a new call is established or a handover is performed,

the BSC selects the TRX and the time slot for the traffic channel based on the
idle channel interference measurements. The frequency hopping has a
significant effect on the idle channel interference measurement results.
When the frequency hopping is used, the frequency of a hopping logical
channel is changed about 217 times in a second. The frequency of the idle
time slots changes according to the same sequence.
In a case of the random hopping, this means that the measured idle channel
interference is likely to be the same for all the TRXs that use the same MAlist. If the interference is averaged over more than one SACCH frame, the
averaging effect is even stronger. However, normally the interferers are
mobiles located in interfering cells. In this case, there are probably
differences in the measured idle channel interferences between different
time slots in the cell. This happens, because the interfering mobiles are only
transmitting during the time slot that has been allocated to them. This is
illustrated in Figure Error! No text of specified style in document.-1.
If the cyclic hopping sequence is used, there might occur differences on the
measured idle channel interference levels between the TRXs on the same
time slot as explained in the following section.
Figure Error! No text of specified style in document.-1. Idle channel
interference in a case of the random RF hopping
33 .what are types of handover?
There are four different types of handover in the GSM system, which involve
transferring a call between:

Channels (time slots) in the same cell


Cells (Base Transceiver Stations) under the control of the
same Base Station Controller (BSC),

Cells under the control of different BSCs, but belonging to the

same Mobile services Switching Center (MSC), and

Cells under the control of different MSCs.

34. what are important parameter of power saving in GSM
Discontinuous transmission
Minimizing co-channel interference is a goal in any cellular system, since it
allows better service for a given cell size, or the use of smaller cells, thus
increasing the overall capacity of the system. Discontinuous transmission
(DTX) is a method that takes advantage of the fact that a person speaks less
that 40 percent of the time in normal conversation [22], by turning the
transmitter off during silence periods. An added benefit of DTX is that power
is conserved at the mobile unit.
The most important component of DTX is, of course, Voice Activity Detection.
It must distinguish between voice and noise inputs, a task that is not as
trivial as it appears, considering background noise. If a voice signal is
misinterpreted as noise, the transmitter is turned off and a very annoying
effect called clipping is heard at the receiving end. If, on the other hand,
noise is misinterpreted as a voice signal too often, the efficiency of DTX is
dramatically decreased. Another factor to consider is that when the
transmitter is turned off, there is total silence heard at the receiving end, due
to the digital nature of GSM. To assure the receiver that the connection is not
dead, comfort noise is created at the receiving end by trying to match the
characteristics of the transmitting end's background noise.
Discontinuous reception
Another method used to conserve power at the mobile station is
discontinuous reception. The paging channel, used by the base station to
signal an incoming call, is structured into sub-channels. Each mobile station
needs to listen only to its own sub-channel. In the time between successive
paging sub-channels, the mobile can go into sleep mode, when almost no
power is used.
All of this increases battery life considerably when compared to analog
: What is Tri-band and Dual-band?
A: A tri-band phone operates at three supported frequencies, such as
900/1800/1900 MHz or 850/1800/1900 MHz. A dual-band phone operates at
two frequencies, such as 850/1900 MHz or 900/1800

RF Optimization and Log File Analysis in GSM

Optimization and Log File Analysis in GSM

1. INTRODUCTION
Every Network needs to be under continues control to maintain/improve the
performance. Optimization is basically the only way to keep track of the
network by
looking deep into statistics and collecting/analyzing drive test data. It is
keeping an eye
on its growth and modifying it for the future capacity enhancements. It also
helps
operation and maintenance for troubleshooting purposes.
Successful Optimization requires:
Recognition and understanding of common reasons for call failure
Capture of RF and digital parameters of the call prior to drop
Analysis of call flow, checking messages on both forward and reverse
links to establish what happened, where, and why.
Optimization will be more effective and successful if you are aware of what
you are
doing. The point is that you should now where to start, what to do and how
to do.
1.1. Purpose and Scope of Optimization
The optimization is to intend providing the best network quality using
available
spectrum as efficiently as possible. The scope will consist all below;
Finding and correcting any existing problems after site implementation
and
integration.
Meeting the network quality criteria agreed in the contract.
Optimization will be continuous and iterative process of improving
overall
network quality.
Optimization can not reduce the performance of the rest of the
network.
Area of interest is divided in smaller areas called clusters to make
optimization
and follow up processes easier to handle.
1.2. Optimization Process
Optimization process can be explained by below step by step description:
1.2.1. Problem Analysis
Analyzing performance retrieve tool reports and statistics for the worst
performing BSCs and/or Sites
Viewing ARQ Reports for BSC/Site performance trends
Examining Planning tool Coverage predictions

Analyzing previous drive test data

Discussions with local engineers to prioritize problems
Checking Customer Complaints reported to local engineers
1.2.2. Checks Prior to Action
Cluster definitions by investigating BSC borders, main cities, freeways,
major roads
Investigating customer distribution, customer habits (voice/data usage)
Running specific traces on Network to categorize problems
Checking trouble ticket history for previous problems
Checking any fault reports to limit possible hardware problems prior to
test
1.2.3. Drive Testing
Preparing Action Plan
Defining drive test routes
6
Collecting RSSI Log files
Scanning frequency spectrum for possible interference sources
Redriving questionable data
1.2.4. Subjects to Investigate
Nonworking sites/sectors or TRXs
Inactive 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
Missing Neighbors
Oneway neighbors
PingPong Handovers
Not happening handovers
Accessibility and Retainability of the Network
Equipment Performance
Faulty Installations
7
1.2.5. After the Test
Post processing of data
Plotting RX Level and Quality Information for overall picture of the driven
area
Initial Discussions on drive test with Local engineers
Reporting urgent problems for immediate action
Analyzing Network feature performance after new implementations
Transferring comments on parameter implementations after new changes
1.2.6. Recommendations

Defining missing neighbor relations

Proposing new sites or sector additions with Before & After coverage plots
Proposing antenna azimuth changes
Proposing antenna tilt changes
Proposing antenna type changes
BTS Equipment/Filter change
Retuning of interfered frequencies
BSIC changes
Adjusting Handover margins (Power Budget, Level, Quality, Umbrella
HOs)
Adjusting accessibility parameters (RX Lev Acc Min, etc..)
Changing power parameters
Attenuation Adds/Removals
MHA/TMA adds
8
1.2.7. Tracking
Redriving areas after implementing recommendations
Create a tracking file to followup implementation of recommendations
1.2.8. Other Optimization Topics
Verifying performance of new sites
Verifying handovers
Verifying data after ReHomes
Investigating GPRS performance
Verifying Sectorizations
Collecting DTI Scan files
Verifying coverage
Verifying propagation model by importing DTI scan files to Planet
Periodic Consistency Checks
Frequency Planning Check
Analyzing cell access parameters
Analyzing Handover parameters
Analyzing Power control parameters
Analyzing Frequency Hopping parameters (HSN, MAIO)
Implementing/analyzing optional features
Keep helping local engineers with emergency cases
Benchmarking
9
1.3. Before Starting
This document was prepared with TEMS screen shots from live examples of
previous
experiences to guide RF Engineers on how to define/analyze problems or
cases and optimize
network. After each case/problem demonstration, specific step to be taken
will be defined and
appropriate recommendation will be given.
The document will be focusing on Drive Testing part of the Optimization

Process and give

definitions on basic GSM principals, features and parameters when needed.
The readers of this document are considered to have basic knowledge of cell
planning and TEMS
Investigation usage. Only little information will be given just to remember
TEMS interface.
10
2. 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 whats happening with a subscriber point of view.
The drive testing is basically collecting measurement data with a TEMS
phone, but the main
concern is the analysis and evaluation part that is done after completition of
the test. Remember
that you are always asked to perform a drive test for not only showing the
problems, but also
explaining them and providing useful recommendations to correct them.
Please note that a
successful analysis should be supported by handling of network statistics
from a statistics tool
(Metrica/NetDocNMS/SRPOSS, etc..) and careful evaluation of coverage
predictions from a
cell planning tool (Planet, DBPlanner, TEMs Cell Planner, etc..). Please see
Figure 1 for a usual
view from TEMS.

Dharmendra Kumar Singh

Email id:hidharmendrasingh@gmail.com
Mobile No: *************
Passport No: ********

0BJECTIVES
To work in high engineering & skilled environment with positive attitude,
seeking assignments in Project management / Networking / Telecom with
an organization of repute in the Telecom sector, to hold a position of
responsibility in an organization with an opportunity of growth of the
organization along with having a long-term relationship and to conduct

myself in such a manner so as to uphold the dignity of profession.

PR0FESSI0NAL
SYN0PSIS
Presently 2G / 3G / RF/Telecom Consultant/Corporate Telecom Trainer in
United Telecom Limited (UTL Technologies Limited) since July 2012 to Till
Date. Ability to perform quality work within deadlines with or without direct
supervision and always work with confidence and hard work. Excellent
written and oral communications, interpersonal, analytical, abstract
reasoning and organizational skills. Extensive knowledge of 2G,3G & Strong
knowledge on RF Engineering
EMPL0YMENT RECITAL
United telecom Ltd
Teleysia Network Pvt. Ltd.
Metrotel Works (Akrosh) Pvt Ltd
Metrotel (Akrosh Consultants
Pvt Ltd)

Associate Telecom
Consultant
RF PR0JECT C00RDINAT0R
SR.RF ENGINEER

July 2012 to Till

Date
Jan 2012- June 2012

RF ENGINEER

OCT 2009- NOV

2010

DEC 2010-Dec-2011

CURRENT J0B RESP0NSIBILITIES

Prepare, schedule and perform training of new hires. Keep knowledge of
branch products
Offer on-going training to existing Telecom/RF employees including Practical
Training on RF Engineering.
Coordinate and implement all activities related to several training courses
offered including course and sending out invitations to participants,
instructor scheduling, maintaining sign-in records, ensuring correct room setup and equipment, creating or ordering materials and maintaining inventory.
Recommends research and develops training courses for Telecom Engineers
& Provide support for mentoring program for new employees and
Foreign
Current Company Job Profile:
At UTL Group, our expertise across multiple domains along with stable
partnerships has been our driving force. We are continuously looking to
extend our business horizons beyond Indian shores. Today, our footprint
extends over 60-plus nations across South Asia, Africa, America and Europe.
Our international business presence in strategic locations has enabled us to
deliver highly reliable solutions, quickly and cost-effectively. Our credibility is

established by our ability to work effectively with some of the biggest players
across various industries. Some of the business conglomerates and
technology partners we work with include Cisco, ZTE, Duratel, UT-Starcom,
Polycom and Emerson.
While we are rapidly expanding as one of India's leading business houses,
our overriding vision remains unchanged to offer the best-in-class solutions
and services that significantly improve the lifestyles of our customers.

PREVIOUS J0B RESP0NSIBILITIES

3G-3.5G / UMTS DT (RF Drive Test), DATA ANALYSER, C0-0rdination
& FIELD OPTIMIZATION
Optimization of UMTS sites based on Coverage_RSCP, Quality_Ec/Io, Pilot
pollution,
Missing neighbors, Soft Handover using drive test datas. Optimize to
improve Ec/Io (Reduce Pilot Pollution) by improving RSCP of dominant cells
and reducing coverage (Interference) of less dominant sectors through
antenna Tilt changes and power changes, thus rectify the overshooting
sectors issues.
Checking Co scrambling code issues. Adding missing 3G-3G neighbors and
deleting the long neighbors using scanner measurements.2G GSM 900/1800
DRIVE TEST, DATA ANALYSER & FIELD OPTIMIZATION: Physical optimization of
existing sites. Finding out the Interference problem & rectify the same.
Identify the reasons for TCH Blocking, TCH Drop & Handover failures.
Primary verification of drive data and taking necessary corrective measures,
like Neighbour addition and deletion and interference analyasis.Providing
appropriate Tilts (Electrical /Mechanical) to reduce the interference or
improve the coverage.3.5G DRIVE TEST - HSDPA & HSUPA drive testing for
checking throughput in Network.HSDPA parameters like CQI, Modulation etc.
2G-GSM,RF DATA ANALYSER, C0-0rdinati0n & FIELD
OPTIMIZATION

Optimization of GSM sites based on Coverage_Rx Level, Quality_Ec/Io,

Pilot pollution
Proposing new sit after analysis of coverage issue. Coverage by skewing
sectors, down tilt/Up tilt, power increase/decrease by using better antenna
gain
Site Auditing and Verifying Hardware, Tilt, Antenna height and Orientation,
According to the site database

 Analyzed the Drive test log files using TEMS Investigation. Find the swap,
Interference in the sites during the optimization & resolve the swap .Missing
neighbors, Soft Handover using drive test datas.
C0MPLETED PR0JECT

PR0JECT:
1) UNINOR-2G:ALCATEL LUCENT, ORISSA, INDIA
Duration: Oct 2009 to JAN 2010
2) VIDEOCON-2G
NSN, TAMILNADU, INDIA
Duration: FEB2010 to DEC 2010
3) AIRCEL 3G
HUWEAI, KERALA, INDIA
Duration:
4) TATA 3G
HUWEAI, KERALA, INDIA
Duration:
5) IDEA 3G
NSN, KERALA, INDIA
Duration:
Tools worked Upon:
TEMS Investigation 8,9,10 & 11
ACTIX
NEMO Outdoor 4 & 5.
ZENEX Probe 2.x & 3.x
Rhodes & Schwartz TSMQ scanner
PCTEL Scanner
MapInfo Professional 8.0, 8.5
MCOM
Technical Skills
Computer Proficiency: Have a good command over MS
Office
Operating Systems: WINDOWS 98, XP, WINDOW 7
Skills, Knowledge and Abilities:
Proven ability to motivate others to study and excel
Ability to work with all levels of bank employees and
maintain credibility, trust, and cooperation
Resolve conflict and handle sensitive employee
situations

Strong oral communication and presentation skills with

ability to teach adults
Strong professional image
Excellent at PC applications to develop training
materials and manuals
Demonstrated organizational skills and implementing
multiple priorities and plans
Professional & Scholastic Qualifications
Standard
B.E. (Electronics &
Communication Engineering)
(R.G.P.V.)
XII
(Bihar. Board)
X
(Bihar. Board)

University/School
Shri Ram College of
Engineering &
Management
Gwalior M.P. India.
Maharaja College, Ara.
Bihar India.
R.N.P.High School, Ara,
Bihar India.

Year
2009

Percentage
70.5%

2003

58.0%

2001

69.0%

PERS0NAL PR0FILE:
Brief Profile:
I am a Committed, gracious and
enthusiastic person.
Strengths:
Flexibility, Competitiveness,
Cooperativeness
Date of Birth:
***********
Fathers name: *************
Gender:
Male
Marital Status: Single
Language Known: Hindi, English
Nationality:
Indian
Declaration:
I hereby declare that all the information furnished
above is true to the best of my knowledge and belief. I shall be responsible
for any action if any of the above statements are incorrect at any stage in
future.

Place: Bangalore
Date-08/01/2013

(Dharmendra
Kumar Singh)

GSM,WCDMA,RF ,RF Optimization Interview Objective Question

Level 2-3 NPO Questions
(RF Planning & Optimisation Engg)
In the following questions, please select one alternative which you think is
the best answer for the particular question.
Q1. SMS broadcast is done over which channel
1.
2.
3.
4.

SDCCH
BCCH
TCH
A&C

Q2. The parameter number of Slot Spread Trans (SLO)(BTS) is used to allocate a
number of CCCH blocks for .
a) Paging Channel (PCH)
b) Random Access Channel (RACH)
c) Access Grant Channel (AGCH)
d) Traffic Channel
Q3. Which of the following comment is true?
a) MAIO step is used to avoid intra-cell interference where as HSN is used to avoid
inter-cell interference
b) HSN is used to avoid intra-cell interference where as MAIO step is used to avoid
inter-cell interference
c) Both MAIO step and HSN are used to avoid intra-cell interference.
d) Both MAIO step and HSN are used to avoid inter-cell interference
Q4. Timer T200 is related with which KPI
a) SDCCH Completion rate
b) Paging success rate
c) TCH assignment success rate
d) All of the above

Q5. Which parameter defines how often paging messages are sent to MS?
a) No of Multi-frames between Paging (MFR)
b) Max No of Retransmission (RET)
c) No of Slots Spread Transmission (SLO)
d) No of Blocks for Access Grant (AG)
Q6. Which parameter is used as a margin to prevent ping-pong location updates?
a) PLMN-Permitted (PLMN)
b) Rx Level Access Minimum (RXP)
c) Cell Reselect Hysteresys (HYS)
d) Handover Margin Level (LMRG)
Q7. Which Parameter describes the minimum received field strength required by
an MS to get any service from the network in that cell in Idle mode?
a) PLMN-Permitted (PLMN)
b) Rx Level Access Minimum (RXP)
c) Cell Reselect Hysteresis (HYS)
d) Direct Access Level (DAL)
Q8. When is location updates carried out?
a) Every time an MS changes its location area under one MSC.
b) Every time an MS changes between two different MSCs
c) On a periodic basis set by a timer
d) All of the above

Q9. Increasing Radio Link Time Out (RLT) from 16 to 24 will improve following
KPI
a) SDCCH Completion rate
b) TCH Completion rate
c) Paging Success rate
d) All of the above

Q10. If a cell is having TCH congestion, which of the following is true?

a) It is having TCH blocking
b) It may have TCH blocking.
c) It is having TCH Drop.
d) All of the above
Q11. Which of the parameter is set to zero for cyclic hopping?
a) BTS Hopping (HOP)
b) Hopping sequence number (HSN)
c) MAIO Offset (MAIO)
d) All of the above
Q12. What is directed retry?
a) A feature that allows a recovery system to restore a BCCH to its original TRX
after fault has been eliminated.
b) It is designed to control the traffic load of a frequency hopping radio network in
which frequencies are reused tightly.
c) It is used in call set up to assign a TCH to an MS from a cell outside the serving
cell due to TCH congestion
d) None of the above

Q13. Which of the following is measured as BER?

a) Received Signal Quality (RX QUAL)
b) Speech Quality Index (SQI)
c) Voice Quality
d) All of above
Q14. Polarization is characterized by
1.
2.
3.
4.

Direction of Magnetic Field

Direction of Electric Field
Direction of Electromagnetic Field
None of Above.

Q15 Which one is correct for TMA, TMB and Repeater?

1. Amplifies U/L, Amplifies D/L, and Amplifies both.

2. Amplifies D/L, Amplifies U/L, and Amplifies both.

3. Amplifies U/L, Amplifies D/L, and Amplifies U/L.
4. Amplifies U/L, Amplifies D/L, and Amplifies D/L.

Q16 Define Beam width of Antenna?

1. Angular distance between the points on two opposite sides of the peak
direction where the radiation intensity drops to the 1/2 of the peak
intensity.
2. Angular distance between the points on two opposite sides of the peak
direction where the radiation intensity drops to the 1/3 of the peak
intensity.
3. Angular distance between the points on two opposite sides of the peak
direction where the radiation intensity drops to the 1/4 of the peak
intensity.
4. Angular distance between the points on two opposite sides of the peak
direction where the radiation intensity drops to the 1/8 of the peak
intensity.
Q17 From which technique we cancel the effect of Rayleigh Fading?
1.
2.
3.
4.

Antenna Hoping.
Frequency Hoping.
Antenna Diversity.
MAIO.

Q18 If HLR=5 Million subs, VLR/HLR=0.7,mErl/Sub=30.Then how much

Capacity is required to cater the subscriber in RF for 70% utilized Network.
1.
2.
3.
4.

150
300
135
165

K
K
K
K

Erl
Erl
Erl
Erl

Q19 Electrical Tilt antenna limits coverage through?

1.
2.
3.
4.

Tilting of Dipoles.
Inserting Phase Shift.
Inserting attenuation.
None of the above.

Q20 Which Antenna has the highest front to back Ratio?

1.
2.
3.
4.

Loop
Yagi
Dipole
Parabolic

Q21 Select relation between forward power and Reflected Power if load is not
connected?
1.
2.
3.
4.

VSWR=1
VSWR=
VSWR=0
VSWR=1/2

Q22 What is the difference between splitter and coupler?

1. Even Distribution of Power in coupler and uneven distribution in
splitter.
2. Uneven Distribution of Power in coupler and even distribution in
splitter.
3. Even Distribution of Power in both.
4. Uneven Distribution of Power in both.
Q23. What are mobility management states in GPRS?
1.
2.
3.
4.

Idle,Standby,Ready
Dedicated,Standby,Ready
Idle,Dedicated,Standby
None of above

Q24. Which modulation is used for EDGE above MCS-4

1.
2.
3.
4.

QPSK
GMSK
8PSK
PSK

Q25. What does SGSN stands for?

1. Serving Gateway Support node

2. Serving GPRS Support node

3. Serving GMSC Support node
4. None of the above

Q26 In dedicated mode, SMS comes on which channel?

a) SDCCH.
b) SACCH.
c) FACCH.
d) None of the above.
Q27 In Dedicated Mode, MS receives which system info. Messages?
1.
2.
3.
4.

System Info 1, 2, 3.
System Info 1, 2, 3,4,13.
System Info 5, 6.
None of the above.

Q28 Freq used in Uplink of Satellite communication is higher while in GSM it is

lower. Why?
1.
2.
3.
4.

Loss freq.
Loss 1/freq.
Loss sqr(freq)
None of the above.

Q29 AMR is used to improve?

1.
2.
3.
4.

SQI
Downlink quality.
Uplink Quality
None of the Above.

Q30 In Idle Mode, MS receives which system info. Messages?

a) System Info 1, 2,3.
b) System Info 1, 2, 3,4,13.
3. System Info 5, 6.
d) None of the above
Q31 The Common Control channel multiframe consists of?
1. 51 time slots.

2. 50 timeslots
3. 4 Time slots
4. 9 Time slots

Q32 Which of the following are true?

1. Type 1 Paging: can address up to 2 mobiles using either IMSI or TMSI.
2. Type 2 Paging: can address up to 3 mobiles, one by IMSI and the other
2 by TMSI.
3. Type 3 Paging: can address up to 4 mobiles using the TMSI only.
4. All of the above.
Q33 In GSM while performing handover
1. The MS breaks connection from source cell and then tunes on the
target cell.
2. The MS continues connection from the source, tunes on the target and
then releases the source cell.
3. MS gets paging message from the target and replies it on its RACH and
gets TCH allocated.
4. MS gets paging message from the target and replies it on its RACH and
gets SDCCH allocated.
Q34 If E-RACH is used then which of the following is true?
1.
2.
3.
4.

GSM range will increase beyond 35Km

It will increase no of RACH channels and release congestion on RACH.
SDCCH assignment will improve.
All above are false.

Q35 In dedicated mode the BTS receives handover command on?

1.
2.
3.
4.

TCH
SDCCH
SACCH
FACCH

Q36 The duration of a single timeslot is?

1.
2.
3.
4.

4.615 ms
1250 ms
0.577 ms
156.25 ms

Q37 Modulation used in GSM radio interface is?

1.
2.
3.
4.

Phase shift keying (PSK)

Gaussian Minimum shift Keying (GMSK)
Frequency modulation.
8PSK.

Q38 TIE stands for?

1.
2.
3.
4.

Terminal Equipment identifier

Transcoder Input Erlang
TRX identifier for Edge TRX
None of the above

Q39 As per GSM Standard in case of frequency hopping the C/I value should
be at least?
1.
2.
3.
4.

3 dB
6 dB
9 dB
12 dB

Q40 In inter BSC handover the handover is controlled by?

1.
2.
3.
4.

GMSC
MSC
Source BSC
Target BSC

Q41 The maximum no of neighbors that can be defined with a cell is?
1.
2.
3.
4.

8
16
32
64

Q42 The permissible value of VSWR for feeder cable is?

1.
2.
3.
4.

< 1.3
>1.3
>1
<2

Q43 The function of Transcoder is

1. To convert 64 kbps speech channel on A interface to 16 kbps speech
channel on A-ter Interface and vice versa.
2. To convert 16 kbps speech channel on A interface to 64 kbps speech
channel on A-ter Interface and vice versa.
3. To convert analogue speech signal from MSC to Digital signal for use of
BSC
4. To convert analogue speech signal from BSC to Digital signal for use of
MSC
Q44 TSC stands for
1.
2.
3.
4.

Time Synchronized Channel

Temporary subscriber code
Transcoder Signaling Controller
Training Sequence Code

Q45 If Cell bar is set to yes on a cell then

1.
2.
3.
4.

It will reject new calls as well as handover calls

It will reject new call assignment but will receive calls by Handover
It will reject Handover but allow new call to come
The BTS will go into locked state.

Q46 DAP stands for

1.
2.
3.
4.

Dual Abis pool

Dynamic Allocation protocol
Dynamic Abis Pool
None of the above

Q47 Who can initiate the GPRS detach

1.
2.
3.
4.

The MS only
The SGSN only
Both the MS and the SGSN
None of the above

Q48 The mapping of logical name/Host name to IP addresses in the GPRS

network is done by
1.
2.
3.
4.

Border Gateway
SGSN
GGSN
DNS

Q49 Where is the mobility management context established in GPRS

1.
2.
3.
4.

In the MSC
In the SGSN
In the GGSN
All of the above

Q50 Which layer uses the functionality of Uplink State Flag (USF)?
1.
2.
3.
4.

RLC Layer
Physical Layer
MAC Layer
All of the above

Q51 How many TDMA frames are there in a PDCH multiframe?

1.
2.
3.
4.

51
52
26
8

Q52 Which coding scheme does not use Forward Error Correction (FEC)?
1.
2.
3.
4.

CS-1
CS-2
CS-3
CS-4

Q53 Which new area is defined in GPRS compared to GSM?

1.
2.
3.
4.

Location Area
Routing Area
Both a and b
None of the above

Q54 Which layer is responsible for segmentation and reassembly of LLC

PDUs and backward error correction (BEC) procedures?
1.
2.
3.
4.

Physical Layer
Application Layer
RLC Layer
MAC Layer

Q55 Which coding scheme has adopted the same coding as used for SDCCH?
1.
2.
3.
4.

CS-1
CS-2
CS-3
CS-4

Q56 What is the single timeslot data rate for coding scheme CS-2
1.
2.
3.
4.

7.8 Kbit/s
10.4 Kbit/s
13.4 Kbit/s
21.4 Kbit/s

Q57. Combiner works in

a) Downlink direction
b) Uplink direction
c) In both direction
d) As a Amplifier

Q58 Number of AMR codec modes used only in FR?

1.
2.
3.
4.

6
4
2
8

Q59 During conference call which channel is used to establish another call1.
2.
3.
4.

SACCH
SDCCH
FACCH
TCH

Q60 What is Duplex spacing.

1. Difference between first frequency of Uplink and last frequency of
Downlink.
2. Difference between first frequency of Downlink and first frequency of
Uplink.
3. Difference between last frequency of Downlink and first frequency of
Uplink.
4. None of the above.
Q61 What does MSRN stands for .
1.
2.
3.
4.

Mobile
Mobile
Mobile
Mobile

Station Registration Number

System Registration Number
Station Roaming Number
Station Register Number.

Q62. If my MCC=404, MNC=05, LAC=100, CI = 14011, then what will be CGI

for same??
1.
2.
3.
4.

4040510014011
404056436BB
4040514433273
4040510033273

Q63. Which information is there in Handover Access Command in Layer 3

Message?
1.
2.
3.
4.

BCCH & BSIC of Source

BCCH & BSIC of Target
Handover Reference Value
All of above.

Q64 What is the use of Immediate Assignment Extended Command?

1. Allocate AGCH for 2 Mobiles
2. Allocate SDCCH for 3 Mobiles

3. Allocate SDCCH for Call and SMS simultaneously.

4. None of Above.
Q65. What is the cause value for normal call release?
1. 16
2. 3
3. 14
4. 45

Q66. Location Update Request falls under which management system?

1. RRM
2. CM
3. CRM
4. MM
Q67. Which system information message contains NCC Permitted Values?
1. SI 6
2. SI 2
3. All of Above.
4. None of Above.

Q68. When timer T3212 expires which process is initiated?

1. Cell Update
2. RAC Update
3. LAC Update
4. Handover
Q69. If AMR FR & AMR HR is enabled in network, then what will be the
formula for counting GSM FR Traffic with help of EOSFLX KPI Reports ?
1. Total Traffic AMR FR Traffic
2. Total Traffic AMR FR Traffic - AMR HR Traffic
3. Total Traffic GSM HR Traffic AMR FR Traffic AMR HR Traffic
4. None of Above.
Q70. By reducing value of RET parameter it will help to improve which KPI?
1. TCH Drop
2. SDCCH Drop
3. HO Success
4. None of above.

Q71. What is the range of AMH TRHO PBGT Margin parameter?

1. -6 to +6, 255
2. -24 to +24, 255
3. -6 to +24, 255
4. +6 to +24, 255
Q72. What is the relation between HO Load Factor and HO Priority Level?
1. Load Factor > Priority Level
2. Load Factor >= Priority Level
3. Load factor < Priority Level
4. Load Factor <=Priority Level
Q73. Which are the basic features helps to distribute traffic in nearby cells?
1. DR
2. IDR
3. AMH
4. All of above
Q74. Using Multi BCF Common BCCH feature operator can expand how many
numbers of TRX in one segment without using another BCCH?
1. 16
2. 24
3. 30
4. 36

Q75. While Using Path loss Criterion C2 which parameter should be made 0
so that this particular cell have higher C2 Value even though having poor C1?
1. CRO
2. TEO
3. Penalty Time
4. None of above.

Q76. Common BCCH feature is implemented in network, then which feature

will help to access the secondary freq. spectrum directly?

1.
2.
3.
4.

DR
DADB
DADL
All of above

Q77. Which types of GSM Reports are generated by Nemo Analyzer?

1. GSM Performance Report
2. GSM Benchmark Report
3. All of above
4. None of above
Q78. What is the range of parameter PMRG?
1. -24to +63
2. -24 to +24
3. -63 to +63
4. 0 to +63
Q79. How many maximum uplink TBF can be there per RTSL?
1. 6
2. 7
3. 8
4. 9
Q80. What should be minimum value of CDED (%) to have 1 RTSL as
dedicated GPRS Timeslot considering 2 TRX as GPRS TRX?
1. 0
2. 1
3. 8
4. 10
Q81. What does TRP Value = 3 means?
1. TCH allocation from BCCH TRX for non-amr user and from beyond
BCCH TRX for amr USER
2. TCH allocation from beyond BCCH TRX for non-amr user and from
BCCH TRX for amr USER
3. All of above
4. None of Above
Q82. How many basic EGPRS MCS Families are there?
1. 1
2. 2
3. 3

4. 4

Q83. Which is / are the main factors affecting the Radio Accessibility for TBF
in UL/ DL?
1. Coverage
2. Capacity
3. Interference
4. All of above.
Q84. Which parameter setting can help to increase the TBF Retainability?
1. UL Power Control
2. DL Power Control
3. All of above.
4. None of above.
Q85. What should be SDCCH GOS when compared to TCH GOS?
1. SD GOS = TCH GOSDTX
2. SD GOS = 1/2(TCH GOS)
3. SD GOS = 1/4(TCH GOS)
4. SD GOS = 2(TCH GOS)
Q86. Which feature/technique is not used to reduce blocking / congestion?
1. Directed Retry
2. Traffic Reason Handover
3. Dynamic SDCCH
4. Intra Cell Handover
Q87. Rx Quality = 3 means BER =?
1. 0.2 - 0.4
2. 6.4 - 12.8
3. 1.6 - 3.2
4. 0.8 - 1.6
Q88. Following is false when using Dynamic SDCCH.
1. SDCCH Handover cannot be used.
2. Free TCH is used when SDCCH is required.
3. SDCCH carrying CBCH cannot be used.
4. Every SDCCH request can be fulfilled by Dynamic SDCCH.
Q89. In Link Budget; what has the least importance?
1. GSM Antenna Gain

2. Path Loss
3. Feeder Loss
4. MS Antenna Gain
Q90. When 2 calls are made from different TRXs of same cell having 1*1 RF
hopping; what plays important role to neglect C/I?
1. MAL ID
2. HSN
3. MAIO Step
4. MAIO Offset
Q91. Frame loss can be reduced by:
1. Speech Coding
2. Channel Coding
3. Interleaving
4. Burst Formatting
Q92. What can be done to overcome combiner loss when cell is upgraded
from 2 TRX to 3 TRX?
1. Remove Combiner
2. Air-Combining
3. HOP = OFF
4. TMA Implementation
Q93. What is the Basic feature amongst below:
1. SAIC
2. STIRC
3. AMR Progressive Power Control
4. Freq. Hopping
Q94. Out of following channels which one is common channel?
1. AGCH
2. SACCH
3. TCH-FR
4. FACCH
Q95. Out of following channels which one is the answer to RACH?
1. SDCCH
2. AGCH
3. FACCH
4. SACCH
Q96. In Air-interface TDMA time-slot means how many Seconds?
1. 576.9us

2. 4.615ms
3. 6.12sec
4. 480ms
Q97. Which type of antenna is used in MS?
1. Dipole
2. Omni
3. Loop
4. Cross-polar
Q98. Choose the correct Erlang Formula?
1. x Erlang= (calls per hour) * (average call duration)/3600 Sec
2. x Erlang= (no. of user)*(3600 sec)/ (calls per hour)
3. x Erlang= (no. of calls)*(no. of user)/ (average call duration)
4. x Erlang= (calls per hour)*(no. of users)/3600 sec
Q99. If GOS of an N/W is 3%, what does it mean?
1. 3 out of 100 calls may fails
2. average call duration is 3min
3. at a time 3% of total users can make a call
4. 3% blocking in the N/W is permitted
Q100. Which type of message is "Identity Request?
1. Mobility Management
2. Radio Resource Management
3. Call Control
4. Call related SS message
Q101. Paging message type 2 contains.
1. Paging message for 3 mobiles
2. Paging message for 2 mobiles
3. Paging message for 4 mobiles
4. Paging message for >4 mobiles
Q102. Out of following which one is not a part of NSS?
1. Mobility Management
2. Connection Management
3. Radio Resource Management
4. Charging
Q103. In L3 messages, out of following Info messages which one carries
Dedicated Mode Information?
1. System Info 2
2. System Info 4

3. System Info 5
4. System Info 13
Q104. Which one out of following is not a part of AMR Codec Modes?
1. 4.6
2. 5.9
3. 7.4
4. 12.2
Q105. Frequency Hopping
1. Eliminates the problem of fading dips
2. Eliminates the problem of ISI
3. is part of channel coding
4. spreads the problem of fading dips to many mobile stations
Q106. ISI is caused by:
1. fading dips
2. the Viterbi equalizer
3. reflection
4. interleaving
Q107. Maximum data throughput / tsl possible incase of GPRS is: X`
1. 18.8kbps
2. 27.2kbps
3. 29.2kbps
4. 21.4kbps
Q108. Out of following which element/s in the GSM N/W can not initiate HO?
1. BSC
2. BTS
3. MSC
4. None of Above
Q109. Out of following, which type of antenna has highest directivity?
1. Dipole
2. Helical
3. Log-Periodic
4. Yaagi-Uda
Q110. When we say the output power of a Transmitter is 30dBm, how many
watts does it mean?
1. 3W
2. 1W
3. 1mW

4. 30mW
Q111. Out of following which one is a passive device?
1. Repeater
2. Cross Polar Antenna
3. TMA (Tower Mount Amplifier)
4. TRX
Q112. Out of following which can not be observed during Drive-test?
1. Rx Quality
2. Location Update
3. Paging Load
4. GPRS Attach
Q113. If a cell is EDGE capable, how much Downlink Throughput can we
guarantee to customer?
1. 59.2kbps
2. 473.6kbps
3. 236.8kbps
4. can't guarantee
Q114. How many blocks of AGCH are reserved in non combined mode?
1.
2.
3.
4.

1-7
0-2
0-7
None of Above.

Q115. What are the contents of authentication triplets?

1.
2.
3.
4.

A3,A5,A8
SRES,RAND,Kc
RAND,A3,A8
SRES,Kc,A8

Q116 Frequency hopping in a network:

1. May or may not be implemented
2. Does not provide optimal gain if the hopping frequencies are less than
4
3. Both above are correct.
4. None of the above.

Q117 .Which of the following functions is not done by SDCCH CHANNEL:

1.
2.
3.
4.
Q118
1.
2.
3.
4.

Authentication
Transmission of short messages
Adaptive power control information from BTS to MS only
Assignment of traffic channel to MS.
How many TS can be used at the most with HSCSD?
2
4
6
8

Q119 What should be the value of C/I when you are in hopping mode?
1.
2.
3.
4.

Above 9
Above 12
Less than 9
All of the above are correct

Q120 Which value of level and quality should be considered for analysis in a
DT log
1.
2.
3.
4.

Full
Sub
Both
None of the above is correct.

Q121 What are the coding schemes observerd in UL/ DL after implementing
EDGE in your Network:
1.
2.
3.
4.

CS1-CS4
MCS1-MCS6
MCS5-MCS9
MCS1-MCS9

Q122 What does DAP stand for?

1.
2.
3.
4.

Dynamic Abis Pool

Dynamic Access Pool
Dynamic Access Protocol
None of the above

Q123 How many codecs can be defined for AMR HR

1.
2.
3.
4.

5
2
6
4

Q124 How many TRXs can be accommodated max on a single E1 where DAP
pool is assigned for 4 TS in a Ultra site
1.
2.
3.
4.

12
16
18
24

Q125 How much traffic will be offered by a sector having 4 TRX with GOS of
2%
1.
2.
3.
4.

24Erlangs
21.03Erlangs
23.56Erlangs
22.12 Erlangs

Q126 Which ND report would you refer in order to find the discrepancy for
Handovers?
1.
2.
3.
4.

Report
Report
Report
Report

163
166
153
208

Q127 On what basis would an optimizer decide whether the site serving is
overshooting:
1.
2.
3.
4.

On the basis of TA
From ND report 232
Physically verifying whether the cell is having up tilt
All of the above

Q128 BBH is generally implemented where:

1.
2.
3.
4.

For dense network

For small capacity network
For cells where tight frequency reuse is required
None of the above

Q129 In case of Directed retry HO:

1.
2.
3.
4.

HO
HO
HO
HO

is
is
is
is

performed
performed
performed
performed

from
from
from
from

TCH of serving to TCH of Adjacent cell

SDCCH of serving to TCH of adjacent cell
TCH of Serving to SDCCH of adjacent cell
SDCCH of serving to SDCCH of adjacent cell

Q130 Which alarm indicates the TRX faulty operation in the system:
1.
2.
3.
4.

7601
7602
7725
7745

Q131 C/I estimation during a DT can be done in:

1.
2.
3.
4.

U/L
D/L
Both A&B
Cannot be estimated.

Q132 Which is the unique feature in TEMS for analsing speech quality:
1.
2.
3.
4.

Rx qual Full
Rx Qual Sub
SQI
Rx Qual.

Q133 Drop calls due to Handovers can be caused basically due to:
1.
2.
3.
4.

Neighbors with Co-BSIC

Neighbor with Co-BCCH
Neighbors with Co-BCCH and Co-BSIC
All of the above.

Q134 Consider a cell where the no calls are happening, the probable causes
would be
1.
2.
3.
4.

Wrong definition of LAC,CI

DMAX=0
Only A is correct
Both A&B are correct.

Q135 What should be the value of Rxlev Access min set:

1.
2.
3.
4.

-47dbm
-110dm
-65dbm
-85dbm

Q136 What would be the output of a cell with parameter setting as

MstxPwrmax=0db,BsTxPWrMax =30db
1.
2.
3.
4.

Cell
Cell
Cell
Cell

will carry max.no of calls

will carry very few calls
will not be latched
with a correct parameter setting.

Q137 What would be the power loss after using a combiner in a sector:
1.
2.
3.
4.

-2db
-1db
-3db
-4db

Q138 What will happen in case where GTRX=Y(Non Edge TRX),EDGE=Y:

1.
2.
3.
4.

TRX will be unlocked

System will not allow the TRX to be unlock
TRX will go in Block state
Both B&C are correct.

Q139 Which report would give you the total payload for GPRS:
1. 232
2. 208
3. 228

4. 226.

Q140 In a Flexi BTS 1 physical TRX would logically represent how many Trx:
1.
2.
3.
4.
Q141
1.
2.
3.
4.

1
2
3
None of the above.
Booster becomes a solution in case of :
Capacity
Coverage
A & B Both
None of the above

Q142 Recommended value of ITCF is :

1.
2.
3.
4.

2
0
1
4

Q143. Which ND report gives the data for RACH rejection on cell level?
5. 134
6. 132
7. 188
8. 111.
Q144. Which ND report would you refer in order to find the discrepancy for
Handovers?
5.
6.
7.
8.

Report
Report
Report
Report

163
166
153
208

Q145.On what basis would an optimizer decide whether the site serving is
overshooting:
5.
6.
7.
8.

On the basis of TA
From ND report 232
Drive test logs
All of the above

Q146.Which ND report would give you the total payload for GPRS:
5.
6.
7.
8.

232
208
228
226.

Q147 What is a Command to check active alarms on bts:

1.
2.
3.
4.

ZERO
ZEQO
ZEOL
ZELO

Q148 Value of BSC Timers can be checked by command:

1.
2.
3.
4.

ZEFO
ZEDO
ZEHO
ZEGO

Q149 ND Report 71 Tells:

1.
2.
3.
4.

Adjacencies having highest success rate

Adjacencies having highest failure rate
All adjacencies
None of the above

Q150.Which report gives value of dedicated data time slots:

1.
2.
3.
4.

051
053
061
063.

Q151. Which is ND Report number for AMR Parameters?

1. 051
2. 111
3. 216
4. 053

Q152. Which report shows percentage of HO attempts happening due to

GPRS?
1. 150
2. 151
3. 153
4. 154
Q153
1.
2.
3.
4.

Which ND report gives detailed analysis of a cell?

204
216
186
226

Q154
1.
2.
3.
4.

In which ND report we can see hourly Traffic Profile for a cell?

180
181
182
186

Q155. In which ND report we can see hourly call drops due to

TCH_RF_NEW_HO counter?
1. 216
2. 213
3. 163
4. 166
Q156. In which ND report we can see adjacency discrepancy between
neighbor definitions?
1. 061
2. 060
3. 067
4. 073
Q157. Which are the Coverage Enhancement Features of NSN System?
1. ICE
2. Reverse ICE
3. Smart Radio Concept(SRC)
4. All of Above
Q158. Which ND Report shows Paging Success Rate per LA?
1. 213

2. 216
3. 186
4. 222
Q159. Which ND report shows EGPRS KPI?
1. 230
2. 226
3. 229
4. 228
Q160
1.
2.
3.
4.

Which counter shows DL multislot assignment in percentage?

msl_13
msl_14
msl_15a
msl_16a

Q161. How many 64 Kbps DAP TSLs are required if MS is using MCS 9
(consider: dedicated data timeslot = 4, single data user attached)?
1. 2
2. 4
3. 6
4. 8
Q162. How many maximum Abis timeslots can be handle by PCU ?
1. 64
2. 128
3. 256
4. 264
Q163. What is the Maximum output power of Metrosite BTS in terms of Watt?
1. 5
2. 10
3. 20
4. 40
Q164. What is the maximum number of TRXs can created per BCSU in BSC
3i with version S12?
1. 110
2. 200
3. 100
4. 220

Q165. Which interface is required to implement combine paging (Voice +

Data)
1. Gs
2. DPM ( Dual Paging Mode)
3. Gn
4. DPT ( Dual Paging Transmission)

Q166. In which ND report we can see TRHO Handovers attempt and success?
1. 153
2. 154
3. 155
4. 156
Q167. How many TRXs can be handled by 1 BB2F Card in Ultra Site BTS?
1. 2
2. 3
3. 4
4. 6
Q168. Which of the following BTS Type do not have combiner in-built in
them?
1. Ultra Site
2. Metro Site
3. Flexi BTS
4. None of above
Q169. Which report will help to see EDAP Congestion?
1. 280
2. 281
3. 128
4. 082
Q170. In which ND report we can see paging deletion counts for cell level?
1. 180
2. 181
3. 182
4. 186

Q171
1.
2.
3.
4.

Out of following, which is true as per NSN Specification?

CDED<=CDEF
CDED>CDEF
CDED=CDEF+CMAX
CDEF=CDED+CMAX

Q172. What should be minimum value of CDED(%) to have 1 RTSL as

dedicated GPRS Timeslot considering 2 TRX as GPRS TRX?
1. 0
2. 1
3. 8
4. 10
Q173
1.
2.
3.
4.

Which report shows Intra Cell Handover Statistics?

150
153
154
158

Q174 What is the maximum data throughput/timeslot can be achieved in

case of MCS 9?
1. 64 Kbps
2. 59.2 Kbps
3. 118 Kbps
4. 230.4 Kbps
Q175
1.
2.
3.
4.

Which BTS Type does not support Rx Diversity (RDIV) parameter?

Flexi Edge BTS
Ultra BTS
Metro BTS
Talk Family BTS

Q176
1.
2.
3.
4.

In case of EDGE which of the following CS offers highest coverage?

MCS 1
MCS 9
MCS 5
CS 1

Q177
1.
2.
3.
4.

Which ND Report shows Trx vise quality distribution?

180
269
196
169

Q178
1.
2.
3.
4.

ND Report gives radio timeslot configuration?

111
222
121
051

Q179
1.
2.
3.
4.

Noise separation feature can be implemented in?

TCSM
BSC 3i
Flexi BTS
TRX

Q180 Which of the following is not a feature of GSM network alone, but also
feature of analog mobile communication network?
1. Digital transmission of user data in air interface
2. Possibility of full international roaming in any country
3. Better speech quality
4. Fully digitized switching exchange
Q181 which of the following is parameter affecting cell sites while planning
the network
1. Antenna height
2. MS power
3. BTS Power
4. None Of Above
Q182
1.
2.
3.
4.

What is E interface?
MSC-MSC
MSC-VLR
MSC-HLR
HLR-VLR

Q183
1.
2.
3.
4.

In GSM which type of handover occurs?

Hard
Soft
Both of the above
Make before break

Q184
1.
2.
3.

Choose the correct bit pattern of a flag in LAP-D format ?

01111110
11111111
10101010.

4. 01010101.
Q185 Mobile identity is a part of?
1.
2.
3.
4.

Physical layer Info

Lap-D Info
BSSMAP Info
GSM L3 Info

Q186 Maximum PLMN Permitted can be ?

a) 7
b) 8
c) 1
d) 2
Q187 how many BSIC possible if NCC=4, no of BCCH ARFCN =8 ?
a) 32
b) 64
c) 256
d) 1024
Q188 DTX helps in
a) Reducing TCH congestion
b) Reducing SDCCH congestion
c) Reducing interference
d) Improving paging success
Q189. BSSAP needs the services of SCCP to
a) Analyze A subscriber data
b) To perform Connectionless signaling with the MSC
c) Send MAP messages to HLR via the MSC
d) To make a virtual connection between the MS and the MSC
Q190. Which of the following is true?
a) MAP stands for Mobile Access Part
b) LAP-D protocol is used to communicate between MSC and BSC
c) MAP is used for communication between MSC and HLR
d) BSSAP is used for communicating between BSC and MS

Q191. If an inter MSC handover occurs during a call, the decision to make
a handover is done by
a) BSC controlling the target cell
b) MSC controlling the target cell
c) BSC controlling the current cell
d) MSC controlling the current cell
Q192. Which of the following is not an advantage of the GSM network
Compared to other networks which use the same frequency band?
a) Lower Carrier to Interference Ratio for signal reception
b) Use of MAP signaling
c) Frequency reuse is more efficient than in other networks
d) Lower bit rate for voice coding
Q193. The basic principle of speech coding in a GSM Mobile Station is
a) A-Law PCM with 8 bits per sample
b) -Law PCM at 104Kbits/s
c) A-Law PCM with special filtering at 13Kbits/s
d) None of the above
Q194. Authentication verification is carried out in
a) HLR
b) MSC
c) VLR
d) Authentication Centre
Q195. No calls initiating in a cell, handover traffic is present
1.
2.
3.
4.

wrong neighbor defined

CGI creation problem
Same BCCH Allocated in neighbor
None of above

Q196. Which of the following facility is not supported by Net monitor?

1. Neighbor Cell Id
2. DTX Status

3. Ciphering status
4. HSN
Q 197. In a cell configured with phase diversity, with air combining, what
should be ideal distance between two antennas of same sector?
1.
2.
3.
4.

At least /4 separated
At least /10 separated
0 distance
None of above

Q198. Which of the following is supported by remote tune combiner?

1.
2.
3.
4.

BB Hopping
RF Hopping
Cyclic Hopping
All of above

Q199. Which of the following is affecting SDCCH capacity on Abis Interface?

1.
2.
3.
4.

TRX Signaling Size

No of TCH in sector
EDAP Pool
OMU Signaling

Q200. Alarm no. 2993 indicates

1. TCH Drop on Abis Interface
2. TCH Drop on Ater Interface
3. TCH Drop on Air Interface
4. TCH Drop on A Interface