Interviewquestionofgsm 141012233825-conversion-gate01

Interview question of GSM
1) Which channel is used to transmitrandom access signals?
BCCH
CCCH Correct!
SDCCH
TCH
2) Which one of the followingis the combination of main BCCH?
TCH+SACCH
FCH+SCH+BCH+CCCH Correct!
SDCCH/8+SACCH/8
FCH+SCH+BCH+SDCCH+SACCH
3) The Value Range of Timing Advance (TA) in GSM is?
0-31
0-127
0-63 Correct!
0-7
4) How many MS can be paged with 1 pagingmassagewith IMSI?
1
2 Correct!
3
4
5) Directed Retry handover means?
TCH to TCH
SDCCH to TCH Correct!
SDCCH to SDCCH
None of Above
6) How many neighbors aremeasured by MS at a time?
5
6 Correct!
7
8
7) Time Duration of Super Frame?
3 Hour 28 minutes 53 seconds 760 ms
6.12 seconds Correct!
235.65 ms
120 ms
8) Maximum number of characters allowed in one SMS?
160 Correct!
170
180
150
9) If you have 5 MHz frequency band what will bethe maximum number of channels as per
GSM system?
25 Correct!
35
20
24
10) Which kind of Handovers more desired in the Network?
Rx Level
Power Budget Correct!
Rx Quality

Interference
11) SDCCH holdingtime for Normal location updateis
3.8ms
3.5sec Correct!
3.5ms
None of them
12) SDCCH holdingtime for call setup (MOC) is
2.7sec Correct!
3.5sec
2.7ms
3.5ms
13) Same BCCH-BSIC combination in adjacency will lead
Will notcauseany problem.
MassiveHandovefailaur
Call drop
B & C Correct!
14) Whatis the reason of ping-pong handover
Cableswap
No dominantcell coverage
Improper handover margine
All of above Correct!
15) If there is interference on the BCCH TRx and the call isgoingon at the hopping Trx
Call will drop
Call will beunafected Correct!
Call will attempt handover due to this interference
None of above
16) If in a cell all KPI is goingwell butits TCH drop is high,there is no any RF and hardware
issuethen this TCH drop will bedue to
Transcoder fail Correct!
Lapd fail
A & B
None of them
17) Which systeminformations areused in idlemode
System information 1,2,3,4,7 & 8 Correct!
System information 1,2,3,4,5,6,7 & 8
System information 1,2,3,4,5,6,9 & 10
System information 1,2,3,4,5,6,7,8,9,10,11,12 & 13
18) Which systeminformations areused for BA list
System information 1,2,3 & 4 Correct!
System information 5,6,8,9,10 & 12
System information 12 & 13
None of them
19) Which systeminformations areused for MA list
System information 13,10,9 & 4
System information 5 & 6 Correct!
None of them
20) Which systeminformations areused for GPRS
System information 12 & 13 Correct!
None of them

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 elementsthat 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.
• < !--[if ppt]-->
• 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 :–
Is the parameter representsthe 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.
• < !--[if ppt]-->
• CQI depends on the RF conditions.
• < !--[if ppt]-->
• 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
• < !--[if ppt]-->
• 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

• < !--[if ppt]-->
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
• < !--[if ppt]-->
• 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
-I 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.
WCDMA/3G Questions & Answers
General
< !--[if !supportLists]-->1. What is the experience and involvement in your current and previous
UMTS design projects?
Talk about your current and previous projects,your responsibilities,design objectives,tools used,activities
involved,challenges,objectives met, etc.

Link Budget
< !--[if !supportLists]-->2. What is a typical NodeB sensitivity level?
The serviceand load determines the NodeB sensitivity;in general, in a no-load condition,the sensitivity is between
-115dBm to -125dBm. For Ericsson,the NodeB sensitivity level is calculated ataround:
CS12.2: -124 dBm
PS-64: -119 dBm
PS-128: -115 dBm
PS-384: -115 dBm
< !--[if !supportLists]-->3. What is a typical UE sensitivity level?
The serviceand load determines the UE sensitivity;in general,in no-load condition,the sensitivity is between -
105dBm and -120dBm. For Ericsson,the UE sensitivity level is calculated ataround:
CS12.2: -119 dBm
PS-64: -112 dBm
PS-128: -110 dBm
PS-384: -105 dBm
HSDPA: -95 dBm
< !--[if !supportLists]-->4. What is a typical NodeB maximum output power?
The maximum NodeB output power is usually 20W or 40W,that is,43dBm or 46dBm.
< !--[if !supportLists]-->5. What is UE maximum transmit power in your link budget?
21dBm.
< !--[if !supportLists]-->6. What is a typical antenna gain?
The antenna gain depends on antenna model; in link budget we use around 17dBi.
< !--[if !supportLists]-->7. What is a typical maximum path loss?
The maximum path loss is dependent on the serviceand vendor recommendations; typically itis in between 135 to
140dB for urban areas and between 150 to 160dBfor rural areas.
< !--[if !supportLists]-->8. What is difference between dBi and dBd?

dBi is the gain in dB from isotropic source;dBd is the gain from a dipolesource.
dBd + 2.15 = dBi.
< !--[if !supportLists]-->9. What is the difference between dB and dBm?
dBm is a unitof power level, measured in milli-watts in logarithmscale,that is,
dBm = 10 * log(W*1000) where W is the power in Watts
dB is not a unit,it is the difference in dBm.
< !--[if !supportLists]-->10. What is 0dBm?
0dBm = 1 milli-watt.
< !--[if !supportLists]-->11. How does TMA work?
A TMA reduces system noise, improves uplink sensitivity and leads to longer UE battery life.
Sensitivity is the minimum inputpower needed to get a suitablesignal-to-noiseratio (SNR) at the output of the
receiver. It is determined by receiver noisefigure, thermo noisepower and required SNR. Thermo noisepower is
determined by bandwidth and temperature, SNR is determined by modulation technique, therefore the only
variableis noisefigure.
The cascadingnoisefigurecan be calculated by Friis equation (Herald Friis):
NFt = NF1 + (NF2-1)/G1 + (NF3-1)/(G1*G2) + ... + (NFi-1)/(G1*G2*...*Gi)
As the equation shows,the firstblock imposes the minimum and the most prominent noisefigure on the system,
and the followingblocks imposes lessand lessimpactto the system provided the gains arepositive.Linear passive
devices have noisefigure equal to their loss.ATMA typically hasa gain of 12dB.
There are typically top jumper, main feeder and a bottom jumper between antenna and BTS. A TMA placed near
antenna with a short jumper from antenna provides the best noisefigure improvement – the noisefigure will be
restricted to the top jumper loss (NF1) and TMA ((NF2-1)/G1), and the remainingblocks (main feeder and bottom
jumper) have littleeffect.
To summarize,a TMA has a gain that’s closeto feeder loss.
< !--[if !supportLists]-->12. What are the pros and cons (advantages and disadvantages) of
TMA?
On the upside,a TMA reduces system noise, improves uplink sensitivity and leads to longer UE battery life.On the
downside, TMA imposes an additional insertion loss(typically 0.5dB) on the downlink and increases site
installation and maintenancecomplexity.
< !--[if !supportLists]-->13. What is typical TMA gain?
TMA typically has a 12 dBgain; however, the effective gain comes from noisefigure reduction and the gain is close
or equivalentto the feeder loss.

< !--[if !supportLists]-->14. WhyTMA are installed at the top near the antenna and not the
bottom near the NodeB?
Based on Friis Equation,havinga TMA near the BTS will havethe top jumper and main feeder losses (noisefigures)
cascaded in and a TMA will notbe able to help suppress the losses.
< !--[if !supportLists]-->15. What is UMTS chip rate?
3.84MHz.
< !--[if !supportLists]-->16. What is processing gain?
Processinggain is theratio of chip rate over data bit rate, usually represented in decibel (dB) scale.For example,
with 3.84MHz chip rate and 12.2k data rate, the processinggain is:
PG12.2k = 10 * log (3,840,000 / 12,200) = 25dB
< !--[if !supportLists]-->17. What are the processing gains for CS and PS services?
CS12.2: 25dB
PS-64: 18dB
PS-128: 15dB
PS-384: 10dB
HSDPA: 2dB
< !--[if !supportLists]-->18. How to calculate maximum number of users on a cell?
To calculatethe maximum number of users (M) on a cell,we need to know:
W: chip rate (for UMTS 3,840,000 chips per second)
EbNo: Eb/No requirement (assuming3dBfor CS-12.2k)
i: other-cell to in-cell interference ratio (assuming60%)
R: user data rate (assuming12,200 kbps for CS-12.2k)
η: loadingfactor (assuming 50%)
Take 12.2kbps as example:
M = W / (EnNo * (1 + i) * R) * η = 3,840,000 (3 * (1 + 0.6) * 12,200) * 0.5 = 32.8
The number of users could also behard-limited by OVSF code space. Take CS12.2k for example:
< !--[if !supportLists]--> A CS-12.2k bearer needs 1 SF128 code.
< !--[if !supportLists]--> Total availablecodes for CS-12.2k = 128 – 2 (1 SF64) – 2 (4 SF256) = 124.

< !--[if !supportLists]--> Consider soft-handover factor of 1.8 and loadingfactor of 50%: 124 / 1.8
*.05 = 34 uers/cell.
19.What is Eb/No?
By definition Eb/No is energy bitover noisedensity,i.e. is the ratio of the energy per information bitto the power
spectral density (of interference and noise) after dispreading.
Eb/No = ProcessingGain +SIR
For example, if Eb/No is 5dBand processinggain is25dBthen the SIR should be -20dB or better.
< !--[if !supportLists]-->20. What are the Eb/No targetsin your design?
The Eb/No targets aredependent on the service:
< !--[if !supportLists]--> On the uplink,typically CS is 5 to 6dB and PS is 3 to 4dB – PS is about2dB
lower.
< !--[if !supportLists]--> On the downlink,typically CS has 6 to 7dB and PS is 5 to 6dB – PS is about
1dB lower.
< !--[if !supportLists]-->21. Whyis Eb/No requirement lower for PS than for CS?
PS has a better error correction capability and can utilizeretransmission,therefore it can afford to a lower Eb/No.
CS is real-timeand cannottolerate delay so it needs a higher Eb/No to maintain a stronger RF link.
< !--[if !supportLists]-->22. What is Ec/Io?
Ec/Io is the ratio of the energy per chip in CPICHto the total received power density (includingCPICHitself).
< !--[if !supportLists]-->23. Sometimeswe say Ec/Io and sometimes we say Ec/No, are they
different?
Io = own cell interference + surroundingcell interference+ noisedensity
No = surroundingcell interference + noisedensity
That is,Io is the total received power density includingCPICHof its own cell,No is the total received power density
excludingCPICHof its own cell.Technically Ec/Io should bethe correct measurement but, due to equipment
capability,Ec/No is actually measured.In UMTS, Ec/No and Ec/Io are often used interchangeably.
< !--[if !supportLists]-->24. What is RSCP?
RSCP stands for Received Signal Code Power – the energy per chip in CPICH averaged over 512 chips.
< !--[if !supportLists]-->25. What is SIR?
SIR is the Signal-to-Interference Ratio – the ratio of the energy in dedicated physical control channel bits to the
power density of interference and noiseafter dispreading.

< !--[if !supportLists]-->26. What is the loading factor in your design?
The designed loadingtypically is50%;however, sometimes a carrier may want to design up to 75% load.
< !--[if !supportLists]-->27. Give a simple definition of pole capacity?
The uplink noiseincreases with the loadingexponentially.When the uplink noise approaches infinity then no more
users can be added to a cell – and the cell loadingis closeto 100% and has reached its “pole capacity”.
Mathematically,to calculatethe uplink polecapacity we need to know:
W: chip rate (for UMTS 3,840,000 chips per second)
R: user data rate (assuming12,200 kbps for CS-12.2k)
f: other-cell to in-cell interference ratio (assuming65%)
EbNo: Eb/No requirement (assuming5dB)
AF: Activity factor (assuming50%)
Pole Capacity =(W/R) / ((1+f) * AF * 10^(EbNo/10)) = 120.6
To calculatethe downlink pole capacity wealso need to know:
α: downlink channels orthogonality factor (assuming55%)
Pole Capacity =(W/R) / ((1- α +f) * 10^(EbNo/10)) = 64.06
< !--[if !supportLists]-->28. What is typical pole capacity for CS-12.2, PS-64, PS-128 and PS-384?
With same assumptions as above:
< !--[if !supportLists]--> CS-12.2k:120.6 (UL), 64.1 (DL).
< !--[if !supportLists]--> PS-64k:34.8 (UL), 12.8(DL).
< !--[if !supportLists]--> PS-128k:16.2 (UL), 8.4 (DL).
< !--[if !supportLists]--> PS-384k:16.2 (UL), 2.8 (DL).
PS-384k has only 128k on the uplink,therefore the uplink capacity isthe same for both.
< !--[if !supportLists]-->29. How many types of handovers are there in UMTS?
Soft handover, softer handover, inter-frequency handover, inter-RAT handover, inter-RAT cell change(UE moving
out of UMTS coverage into GSM/GPRS/EGDGE coverage).
< !--[if !supportLists]-->30. What is soft handover and softer handover?
< !--[if !supportLists]--> Softhandover: when a UE is connected to cells owned by different NodeB.

< !--[if !supportLists]--> Softer handover: when a UE is connected to cells owned by the same
NodeB.
< !--[if !supportLists]-->31. How does soft/softer handover work?
< !--[if !supportLists]--> Soft/softer handover downlink:UE rake receiver performs maximum ratio
combining,i.e. UE combines multi-path signalsand forma stronger signal.
< !--[if !supportLists]--> Softhandover uplink:RNC performs selection combining,i.e. RNC selects
the better signal comingfrommultipleNodeB.
< !--[if !supportLists]--> Softer handover uplink:NodeB performs maximum ratio combining,i.e.
NodeB rakereceiver combines signalsfromdifferent paths and forms a stronger signal.
32. Whyis there “soft handover gain”?
Soft handover gain comes from the following:
< !--[if !supportLists]--> Macro diversity gain over slowfading.
< !--[if !supportLists]--> Micro diversity gain over fastfading.
< !--[if !supportLists]--> Downlink load sharingover multipleRF links.By maintainingmultiplelinks
each link could transmitata lower power, resultingin lower interference therefore a gain.
< !--[if !supportLists]-->33. Briefdescribe the advantages and disadvantages of soft handover?
Advantages:
< !--[if !supportLists]--> Overcome fadingthrough macro diversity.
< !--[if !supportLists]--> Reduced Node B power which in turn decreases interference and increases
capacity.
< !--[if !supportLists]--> Reduced UE power (up 4dB), decreasinginterference and increasingbattery
life.
Disadvantages:
< !--[if !supportLists]--> UE usingseveral radio links requires morechannelization codes,and more
resources on the Iub and Iur interfaces.
< !--[if !supportLists]-->34. What are fast fading and slow fading?
Fastfadingis also called multi-path fading,as a resultof multi-path propagation.When multi-path signalsarriving
at a UE, the constructiveand destructive phases create a variation in signal strength.
Slow fadingis also called shadowing.When a UE moves away from a cell the signal strength drops down slowly.

< !--[if !supportLists]-->35. What are fast fading margin and slow fading margin?
To factor in the fastfadingand slowfading,we need to have a margin in the link budget and they are called fast
fadingmargin and slowfadingmargin.
In link budget, the fast fadingmargin is usually setto 2-3; slowfadingmargin is setto 7-10.
< !--[if !supportLists]-->36. What is a typical soft handover gain in your link budget?
· CS-12.2k: 3dB (UL), 2dB (DL).
< !--[if !supportLists]--> PS-64k:1dB (UL), 0dB (DL).
< !--[if !supportLists]-->37. What is the percentage in time a UE is expected to be in soft or
softer handover?
Typically a UEshould be in soft handover mode at no more than 35 to 40% of the time; in softer handover mode at
about 5% of the time.
< !--[if !supportLists]-->38. What is a typical EiRP?
The EiRP depends NodeB transmitpower, cableand connector loss and antenna gain.With a samplesystem of
43dBm transmitpower, a 3dB cableand connector loss and a 17dBi antenna gain,the EiRP = 43 – 3 + 17 = 57dBm.
< !--[if !supportLists]-->39. How much power usually a NodeB is allocated to control channels?
The power allocated to control channels may depend on equipment vendor recommendation. Typically no more
than 20% of the total NodeB power is allocated to control channels,includingCPICH.However, if HSDPA is
deployed on the same carrier then the total power allocated to control channel may go up to 25 to 30% becauseof
the additional HSDPAcontrol channels required.
< !--[if !supportLists]-->40. What is a typical CPICH power?
CPICH power typically takes about10% of the total NodeB power. For a 20W (43dBm) NodeB, CPICH is around 2W
(33dBm).
In urban areas where in-buildingcoverageis taken careof by in-buildinginstallations,theCPICH may sometimes go
as lowas 5% because:
< !--[if !supportLists]--> The coverage area is small sinceusers arecloseto the site, and
< !--[if !supportLists]--> More power can be allocated to traffic channels.
< !--[if !supportLists]-->41. How much is your HSDPA (max) link power?

HSDPA link power is typically 4 to 5dB below the maximum NodeB maximum output power. For example, for
43dBm maximum NodeB power the HSDPA link power is 39dBm.
< !--[if !supportLists]-->42. Consider downlink only, what are the major components in
calculating maximum path loss, starting from NodeB?
< !--[if !supportLists]--> NodeB CPICH transmitpower.
< !--[if !supportLists]--> Jumper and feeder connector loss.
< !--[if !supportLists]--> Antenna gain.
< !--[if !supportLists]--> Over-the-air loss.
< !--[if !supportLists]--> Building/ vehiclepenetration loss.
< !--[if !supportLists]--> Body loss.
< !--[if !supportLists]--> Etc.
< !--[if !supportLists]-->43. What is maximum path-loss?
The maximum path-loss is howmuch signal isallowed to drop from a transmitter to a receiver and maintains as
good signal.
< !--[if !supportLists]-->44. Simple link budget: with a 30dBm CPICH and a -100dBm UE
sensitivity, ignoring anything in between, what is the maximum path loss?
30 – (–100) = 30 + 100 = 130dB.
< !--[if !supportLists]-->45. Suppose I have a maximum path-loss of 130dBm, what is the new
path-loss if a 5dB body loss is added?
125dB.
< !--[if !supportLists]-->46. What is channelization code?
Channelization codes areorthogonal codes used to spread the signal and henceprovides channel separation,that
is,channelization codes areused to separate channels froma cell.
< !--[if !supportLists]-->47. How many channelization codes are available?
The number of channelization codes availableis dependent on the length of code. In the uplink the length is
defined as between 4 and 256. In the downlink the length is defined as between 4 and 512.
< !--[if !supportLists]-->48. Are channelization codes mutually orthogonal? If so, why is
“Orthogonality Factor” required in the link budget?

Yes, channelization codes aremutually orthogonal.Nonetheless, due to multi-path with variabletime delay,
channels fromthe samecell are no longer perfectly orthogonal and may interfere with each other.
A “Downlink Orthogonality Factor”, typically 50-60%,is therefore needed in the link budget to accountfor the
interference – and hence reduces pole capacity.
< !--[if !supportLists]-->49. What is scrambling code? How many scrambling codes there are?
Scramblingcodes areused to separatecells and UEs from each other, that is,each cell or UE should have a unique
scramblingcode.There are 512 scramblingcodes on the downlink and millionson the uplink.
< !--[if !supportLists]-->50. What is scrambling “code group”?
The 512 scramblingcodes aredivided into 64 code groups – each code group has 8 scramblingcodes.
Code group i (i = 0 to 63) has codes from i*8 to (i+1)*8-1, i.e. (0-7) (8-15)…(504-511).
< !--[if !supportLists]-->51. Do you divide scrambling code groups into subgroups? Please give
an example.
Yes, we dividethe 64 code groups into subgroups:
< !--[if !supportLists]--> Macro layer group:24 code groups reserved for macro (outdoor) sites.
< !--[if !supportLists]--> Micro layer group:16 code groups reserved for micro (in-building) sites.
< !--[if !supportLists]--> Expansion group:24 code groups reserved for future expansion sites.
< !--[if !supportLists]-->52. Which service usually needs higher power, CS or PS?
Consider downlink and take CS-12.2 and PS-384k for example. The processinggain is 25 for CS-12.2 and 10 for PS-
384. The Eb/No requirement is 7 for CS-12.2 and 5 for PS-384. Therefore the power requirement is higher for CS-
12.2 than PS-384.
< !--[if !supportLists]-->53. What is Eb/No requirement for HSDPA?
The Eb/No requirement for HSDPA varies with user bitrate (data rate), typically 2 for 768kbps and 5 for 2Mbps.
< !--[if !supportLists]-->54. What is “noise rise”? What does a higher noise rise mean in termsof
network loading?
For every new user added to the service,additional noiseis added to the network. That is,each new user causes a
“noise rise”.In theory, the “noiserise” is defined as the ratio of total received wideband power to the noisepower.
Higher “noise rise”valueimplies more users areallowed on the network, and each user has to transmithigher
power to overcome the higher noiselevel.This means smaller path loss can betolerated and the cell radius is
reduced. To summarize,a higher noiserisemeans higher capacity and smaller footprint,a lower noiserisemeans
smaller capacity and bigger footprint.
< !--[if !supportLists]-->55. What is “pilot pollution”?

Simply speaking,when the number of strong cells exceeds the active set size, there is “pilotpollution”in the area.
Typically theactiveset sizeis 3,so if there are more than 3 strong cells then there is pilotpollution.
Definition of “strong cell”: pilots within the handover window sizefrom the strongest cell.Typical handover
window sizeis between 4 to 6dB. For example, if there are more than 2 cells (besides thestrongest cell) within 4dB
of the strongest cell then there is pilotpollution.
< !--[if !supportLists]-->56. What is a typical handover window size in your network?
A handover window sizeis usually between 4 to 6dB.
< !--[if !supportLists]-->57. What is “soft handover” and “softer handover”?
“Soft handover” is when UE has connection to multiplecells on different NodeB.
“Softer handover” is when UE has connection to multiplecells on same NodeB.
In downlink a UE can combine signalsfromdifferent cells,improvingthe signal quality.For uplink and soft
handover, RNC selects the best signal fromdifferent NodeB. For uplink and softer handover, a NodeB combines
the signal fromdifferent sectors.
< !--[if !supportLists]-->58. Duringa handover, if one cell sends a power down request and two
cells send a power up request, shall the UE power up or power down?
Power down. As long as a good link can be maintained it is notnecessary to power up in order to maintain multiple
links.Maintainingunnecessary multiplelinksincreases noiseriseand shall beavoided.
< !--[if !supportLists]-->59. Suppose we are designing a CS networkand a PS network, is there a
major difference in the design consideration?
Server dominanceis the key difference. In a CS network we shall limitthe number of strong servers in any given
area to no more than the activeset sizeto avoid pilotpollution (in thedownlink).In a PS network, however, there
isn’tsoft handover in the downlink so the server dominanceis very important – meaning ideally thereshould be
only one dominant server in a given area.
< !--[if !supportLists]-->60. What is the active set size on your network?
3.
< !--[if !supportLists]-->61. How many fingers does a UE rake receiver have?
4.
< !--[if !supportLists]-->62. What is “compressed mode”?
Before UE can perform inter-frequency or IRAT handover, it needs to have some time to lock on to the control
channel of the other frequency or system and listen to the broadcastinformation.Certain idleperiods arecreated
in radio frames for this purposeand is called “compressed mode”.
< !--[if !supportLists]-->63. Describe the power control schemes in UMTS?

< !--[if !supportLists]--> Open loop – for UE to access the network, i.e. used at call setup or initial
access to set UE transmitpower.
< !--[if !supportLists]--> Closed outer loop:RNC calculates theSIR target and sends the target to
NodeB (every 10ms frame).
< !--[if !supportLists]--> Closed inner loop:NodeB sends the TPC bits to UE to increaseor decrease
the power at 1,500 times a second.
< !--[if !supportLists]-->64. What is the frequency of power control (how fast is power control)?
< !--[if !supportLists]--> Open loop: depends on parameter setting:
T300 – time to waitbetween RRC retries (100ms to 8000 ms, typical 1500ms)
< !--[if !supportLists]--> Closed outer loop:100 times a second.
< !--[if !supportLists]--> Closed inner loop:1,500 times a second.
< !--[if !supportLists]-->65. Brieflydescribe why open loop power control is needed and how it
works?
< !--[if !supportLists]--> When a UE needs to access to the network ituses RACH to begin the
process.
< !--[if !supportLists]--> RACH is a shared channel on the uplink used by all UE, therefore may
encounter contention (collision) duringmultipleuser access attempts and interfere with each other.
< !--[if !supportLists]--> Each UE must estimate the amount of power to useon the access attempt
sinceno feedback from the NodeB exists as itdoes on the dedicated channel.
< !--[if !supportLists]--> The purpose of open loop power control is to minimize the chanceof
collision and minimizethe initial UEtransmitpower to reduce interference to other UE.
nsmitpower = Primary_CPICH_Power – CPICH_RSCP + UL_Interferrnce + constant_Value_Cprach
< !--[if !supportLists]--> Instead of sendingthe whole message, a “test” (preamble) is sent.
< !--[if !supportLists]--> Waitfor answer from NodeB.
< !--[if !supportLists]--> If no answer from NodeB increasethe power.
< !--[if !supportLists]--> Try and try until succeed or timeout.
< !--[if !supportLists]-->66. What is power control “headroom”?
Power control “headroom” is also called “power rise”.In a non-fadingchannel the UE needs to transmita certain
fixed power. In a fadingchennel a UE reacts to power control commands and usually increases thetransmitpower.

The difference between the average power levels of fadingand non-fadingchannels is called “power rise”or
“headroom”.
< !--[if !supportLists]-->67. When in 3-way soft handover, if a UE receives power down request
from one cell and power up request from the other 2 cells, should the UE power up or down and why?
Power down. Maintainingonegood link is sufficientto sustain a call and havingunnecessary stronger linkscreates
more interference.
< !--[if !supportLists]-->68. Suppose two UE are served by the same cell, the UE with weaker
link (poor RF condition) uses more “capacity”, why does this mean?
The UE with weaker RF link will requireNodeB to transmithigher traffic power in order to reach the UE, resulting
in less power for other UE – therefore consumes more “capacity”.
< !--[if !supportLists]-->69. Under what circumstances can a NodeB reach its capacity? What are
the capacity limitations?
NodeB reaches its maximum transmitpower, runs out of its channel elements, uplink noiserisereaches its design
target, etc.
< !--[if !supportLists]-->70. What is “cell breathing” and why?
The cell coverage shrinks as theloadingincreases,this is called cell breathing.
In the uplink,as more and more UE are served by a cell,each UE needs to transmithigher power to compensate
for the uplink noiserise.As a consequence, the UE with weaker link (UE at greater distance) may not have enough
power to reach the NodeB – therefore a coverage shrinkage.
In the downlink,the NodeB also needs to transmithigher power as more UE are being served. As a consequence
UE with weaker link (greater distance) may not be reachableby the NodeB.
< !--[if !supportLists]-->71. IsUMTS an uplink-limited or downlink-limited system?
A UMTS system could be either uplink-limited or downlink-limited depending on the loading.In a lightly loaded
system, the UE transmitpower sets a coverage limitation therefore it is uplink-limited.In a heavily loaded system,
the NodeB transmitpower limits thenumber of UEs itcan serve therefore it is downlink-limited.
< !--[if !supportLists]-->72. What is the impact of higher data rate on coverage?
Higher data rate has lower processinggain and therefore a NodeB needs to transmitmore power to meet the
required Eb/No; this means the coverage is smaller for higher data rate.
< !--[if !supportLists]-->73. What is OCNS?
OCNS stands for Orthogonal Channel NoiseSimulator.It is a simulated network load usually by increasingthenoise
risefigurein the NodeB.

UTRAN
< !--[if !supportLists]-->74. What are the interfaces between each UTRAN component?
Uu: UE to NodeB
Iub:NodeB to RNC
Iur: RNC to RNC
Iu: RNC to MSC
< !--[if !supportLists]-->75. Brieflydescribe the UE to UTRAN protocol stack (air interface
layers).
The radio interfaceis divided into 3 layers:
< !--[if !supportLists]-->1. Physical layer (Layer 1, L1): used to transmitdata over the air,responsible
for channel coding,interleaving,repetition, modulation,power control,macro-diversity combining.
< !--[if !supportLists]-->2. Linklayer (L2): is splitinto 2 sub-layers –Medium Access Control (MAC)
and Radio Link Control (RLC).
< !--[if !supportLists]--> MAC: responsiblefor multiplexingdata from multipleapplicationsonto
physical channelsin preparation for over-the-air transmition.
< !--[if !supportLists]--> RLC: segments the data streams into frames that aresmall enough to be
transmitted over the radio link.
< !--[if !supportLists]-->3. Upper layer (L3): vertically partitioned into 2 planes:control planefor
signalingand user plan for bearer traffic.
< !--[if !supportLists]--> RRC (Radio Resource Control) is the control plan protocol:controls the radio
resources for the access network.
In implementation:
< !--[if !supportLists]-->1. UEhas all 3 layers.
< !--[if !supportLists]-->2. NodeB has Physical Layer.
< !--[if !supportLists]-->3. RNC had MAC layer and RRC layer.
< !--[if !supportLists]-->76. Brieflydescribe UMTS air interface channel types and their
functions.
There are 3 types of channels across air interface–physical channel,transportchannel and logical channel:
< !--[if !supportLists]-->1. Physical Channel:carries data between physical layersof UE and NodeB.

< !--[if !supportLists]-->2. TransportChannel:carries data between physical layer and MAC layer.
< !--[if !supportLists]-->3. Logical Channel:carries data between MAC layer and RRC layer.
< !--[if !supportLists]-->77. Give some examples of Physical, Transport and Logical channels.
< !--[if !supportLists]-->1. Logical Channel:
< !--[if !supportLists]--> Control channel:BCCH, PCCH, CCCH, DCCH.
< !--[if !supportLists]--> Traffic channel:DTCH, CTCH.
< !--[if !supportLists]-->2. TransportChannel:
< !--[if !supportLists]--> Common control channel: BCH, FACH, PCH, RACH, CPCH.
< !--[if !supportLists]--> Dedicated channel:DCH, DSCH.
< !--[if !supportLists]-->3. Physical Channel:
< !--[if !supportLists]--> Common control channel: P-CCPCH, S-CCPCH, P-SCH, S-SCH, CPICH, AICH,
PICH, PDSCH, PRACH, PCPCH, CD/CA-ICH.
< !--[if !supportLists]--> Dedicated channel:DPDCH, DPCCH.
< !--[if !supportLists]-->78. What are the RRC operation modes?
Idlemode and connected mode.
< !--[if !supportLists]-->79. What are the RRC states?
There are 4 RRC States: Cell_DCH, Cell_FACH, URA_PCH and Cell_PCH.
URA = UTRAN Registration Area.

< !--[if !supportLists]-->80. What are transparent mode, acknowledged mode and
unacknowledged mode?
< !--[if !supportLists]--> Transparentmode corresponds to the lowest serviceof the RLC layer,no
controls and no detection of missingdata.
< !--[if !supportLists]--> Unacknowledged mode offers the possibility of segment and concatenate
of data but no error correction or retransmission therefore no guarantee of delivery.
< !--[if !supportLists]--> Acknowledged mode offers, in addition to UM mode functions,
acknowledgement of transmission,flowcontrol,error correction and retransmission.
< !--[if !supportLists]-->81. Which layer(s) perform ciphering function?
RRC – for acknowledged mode (AM) and unacknowledged mode (UM).
MAC – for transparentmode (TM).
< !--[if !supportLists]-->82. What is OVSF?
Orthogonal VariableSpreadingFactor.
< !--[if !supportLists]-->83. How many OVSF code spaces are available?
< !--[if !supportLists]--> Total OVSF codes = 256.
< !--[if !supportLists]--> Reserved: 1 SF64 for S-CCPCH, 1 SF256 for CPICH, P-CCPCH, PICH and AICH
each.
< !--[if !supportLists]--> Total availablecodespace= 256 – 4 (1 SF64) – 4 (4 SF256) = 248.
< !--[if !supportLists]-->84. Can code space limit the cell capacity?

Yes, cell capacity can behard-limited by code space.Take CS-12.2k for example:
< !--[if !supportLists]--> A CS-12.2k bearer needs 1 SF128 code.
< !--[if !supportLists]--> Total availablecodes for CS-12.2k = 128 – 2 (1 SF64) – 2 (4 SF256) = 124.
< !--[if !supportLists]--> Consider soft-handover factor of 1.8: 124 / 1.8 = 68 uers/cell.
< !--[if !supportLists]-->85. Can a user have OVSF code as “1111”?
No, because “1111…” (256 times) is used by CPICH.
< !--[if !supportLists]-->86. What are the symbol rates (bits per symbol) for BPSK, QPSK, 8PSK
and 16QAM?
< !--[if !supportLists]--> BPSK: 1.
< !--[if !supportLists]--> QPSK:2.
< !--[if !supportLists]--> 8PSK:3.
< !--[if !supportLists]--> 16QAM: 4.
< !--[if !supportLists]-->87. Brieflydescribe UMTS frame structure.
< !--[if !supportLists]--> UMTS frame duration = 10ms.
< !--[if !supportLists]--> Each frame is divided into 15 timeslots.
< !--[if !supportLists]--> Each timeslotis divided into 2560 chips.
< !--[if !supportLists]--> Therefore 2560 chips/TS * 15 TS/frame * (1000ms/10ms) frame/sec =
3,840,000 chip/sec.
< !--[if !supportLists]-->88. What is cell selection criterion?
Cell selection is based on:
< !--[if !supportLists]--> Qmean:the average SIR of the target cell.
< !--[if !supportLists]--> Qmin:minimum required SIR.
< !--[if !supportLists]--> Pcompensation:a correction valuefor difference UE classes.
S = Qmean - Qmin - Pcompensation
< !--[if !supportLists]--> If S>0 then the cell is a valid candidate.
< !--[if !supportLists]--> A UE will camp on the cell with the highest S.

< !--[if !supportLists]-->89. Brieflydescribe Capacity Management and its functions:
Capacity Management is responsiblefor the control of the load in the cell.Itconsists of 3 main functions:
< !--[if !supportLists]--> Dedicated Monitored Resource Handling:tracks utilization of critical
resources of the system.
< !--[if !supportLists]--> Admission Control:accepts/refuses admission requests based on the
current load on the dedicated monitored resources and the characteristics of the request
< !--[if !supportLists]--> Congestion Control: detects/resolves overload situations
Planning
< !--[if !supportLists]-->90. What are the major 4 KPIs in propagation model tuning and typical
acceptable values?
The 4 KPIs arestandard deviation error,root mean squareerror, mean error and correlation coefficient.The
typical acceptablevalues are:
< !--[if !supportLists]--> Standard deviation error:the smaller the better, usually 7 to 9dB.
< !--[if !supportLists]--> Mean error: the smaller thebetter, usually 2 to3.
< !--[if !supportLists]--> Root mean squareerror: the smaller thebetter, usually
< !--[if !supportLists]--> Correlation coefficient:the larger the better, usually 70%to 90%.
< !--[if !supportLists]-->91. What is the minimum number of bins required for a certain
propagation model?
The more bins the more likely to come up with a good model. Usually a minimumof 2,000 bines is considered
acceptable,but sometimes as low as 500 bins may be accepted.
< !--[if !supportLists]-->92. How many scrambling codes are there?
There are 512 scramblingcodes in the downlink and 16,777,216 codes in the uplink.
< !--[if !supportLists]-->93. How many scrambling code groups are there for downlink?
There are 64 code groups, each group has 8 scramblingcodes.
< !--[if !supportLists]-->94. Can we assign same scrambling codes to sister sectors (sectors on
same site)?
No, because scramblingcodeon the downlink is used for cell identity.As a requirement, scramblingcodes haveto
maintain a safeseparation to avoid interference.

< !--[if !supportLists]-->95. Are scrambling codes orthogonal?
No, scramblingcodes arenot orthogonal sincethey are not synchronized ateach receiver. They are pseudo
random sequences of codes.
< !--[if !supportLists]-->96. Can we assign scrambling codes 1, 2 and 3 to sister sectors?
Yes.
< !--[if !supportLists]-->97. In IS-95 we have a PN reuse factor (PN step size) and therefore
cannot use all 512 PN codes, why isn’t it necessary for UMTS scrambling codes?
Because IS-95 is a synchronized network, different PN codes have the same code sequence with a time shift,
therefore we need to maintain a certain PN step sizeto avoid multi-path problem. For example, if two sectors in
the neighborhood have a small PNseparation then signal arrivingfromcell A may run into the time domain of cell
B, causinginterference.
UMTS, on the other hand, is not a synchronized network and all scramblingcodes aremutually orthogonal so no
need to maintain a step size.
< !--[if !supportLists]-->98. What are coverage thresholds in your UMTS design and why?
The coverage thresholds arebased on UE sensitivity,fadingand penetration loss.AssumingUE sensitivity of -
110dBm, fade margin of 5dB:
< !--[if !supportLists]--> Outdoor:-110dBm sensitivity + 5dB fade margin = -105dBm.
< !--[if !supportLists]--> In-vehicle:-110dBm+ 5dB + 8dB in-vehiclepenetration loss =-97dBm.
< !--[if !supportLists]--> In-building:-110dBm + 5dB + 15dB in-buildingpenetration loss =-90dBm.
< !--[if !supportLists]-->99. What is the Ec/Io target in your design?
The Ec/Io target typically isbetween -12 to -14dB. However, if a network is designed for data then the Ec/Io target
could go higher to around -10dB because server dominanceis more critical for a data network – sincethere isn’t
software in the downlink.
< !--[if !supportLists]-->100.What is“Monte Carlo simulation”?
SinceUMTS coverage is dependent on the loading,static coverageand quality analysis(RSCP and Ec/Io) represents
the network performance in no-load condition.Monte Carlo simulation istherefore used to illustratenetwork
performance under simulated loadingconsition.
< !--[if !supportLists]-->101.What is the key difference between a static analysis and a Monte
Carlo simulation?
Static analysis can only showRSCP and Ec/Io in no-load condition.Monte Carlo simulation notonly can show RSCP
and Ec/Io in simulated loadingcondition butalso can showmany more others: mean served, cell loading,uplink
and downlink capacity limitsreached,etc.

< !--[if !supportLists]-->102.What should be run first (what information should be ready and
loaded) before running a Monte Carlo simulation?
Before runningMonte Carlo simulation,the followingshould becompleted or in place.
< !--[if !supportLists]--> Run prediction.
< !--[if !supportLists]--> Spread the traffic.
< !--[if !supportLists]--> Defineterminal types.
< !--[if !supportLists]-->103.How many snap shots and iteration do you usually have when
running Monte Carlo simulation?
(Depend on software tool recommendations).
< !--[if !supportLists]-->104.What are the design KPI’s?
(RSCP, Ec/Io, mean served, soft handover ratio…)
< !--[if !supportLists]-->105.What plots do you usually check after running Monte Carlo for
trouble spots?
(RSCP, Ec/Io, serviceprobability,reasons for failure…)
< !--[if !supportLists]-->106.What are the typical reasons of failure in Monte Carlo simulation?
< !--[if !supportLists]--> Downlink Eb/No failure(Capacity).
< !--[if !supportLists]--> Downlink Eb/No failure(Range).
< !--[if !supportLists]--> Uplink Eb/No failure.
< !--[if !supportLists]--> Low pilotSIR.
< !--[if !supportLists]--> Noiseriselimitreached.
< !--[if !supportLists]-->107.What does“traffic spread” mean?
“Traffic spread”means spreadingtraffic (number of terminals) in a cell coverage area.
< !--[if !supportLists]-->108.Do you use live traffic or even-load traffic in your design?
(Depends).
Optimization
< !--[if !supportLists]-->109.What are the optimization tools you use?

Drive test, analysis,others?
< !--[if !supportLists]-->110.Are System Information Blocks (SIB) transmitted all the time?
No, system information block is multiplexed with synchronization channel.Synchronization channel occupies the
firsttime slot(TS) and SIB occupies the other 9 time slots.
< !--[if !supportLists]-->111.How does UE camp (synchronize) to a NodeB?
< !--[if !supportLists]-->1. UEuses the primary synchronization channel (P-SCH) for slotalignment(TS
synchronization).
< !--[if !supportLists]-->2. After aligningto NodeB time slot,UE then uses secondary synchronization
channel (S-SCH) to obtain frame synchronization and scramblingcodegroup identification.
< !--[if !supportLists]-->3. UEthen uses scramblingcodeID to obtain CPICH, thus campingto a NodeB.
< !--[if !supportLists]-->112.What could be the cause of soft handover failure?
< !--[if !supportLists]--> UE issue.
< !--[if !supportLists]--> Resourceunavailableattarget NodeB.
< !--[if !supportLists]--> InadequateSHO threshold defined.
< !--[if !supportLists]-->113.What are the three sets in handover?
The 3 sets in handover are:
< !--[if !supportLists]--> Activeset – the listof cells which arein soft handover with UE.
< !--[if !supportLists]--> Monitored set –the listof cells notin active set but RNC has told UE to
monitor.
< !--[if !supportLists]--> Detected set –listof cells detected by the UE but not configured in the
neighbor list.
< !--[if !supportLists]-->114.What are the major differences between GSM and UMTS handover
decision?
GSM:
< !--[if !supportLists]--> Time-based mobilemeasures of RxLev and RxQual – mobilesends
measurement report every SACH period (480ms).
< !--[if !supportLists]--> BSC instructs mobileto handover based on these reports.

UMTS:
< !--[if !supportLists]--> Event-triggered reporting – UE sends a measurement report only on certain
event “triggers”.
< !--[if !supportLists]--> UE plays more partin the handover decision.
< !--[if !supportLists]-->115.What are the events 1a, 1b, 1c, etc.?
< !--[if !supportLists]--> e1a – a Primary CPICHenters the reportingrange, i.e. add a cell to active
set.
< !--[if !supportLists]--> e1b – a primary CPICH leaves the reportingrange, i.e. removed a cell from
activeset.
< !--[if !supportLists]--> e1c – a non-activeprimary CPICH becomes better than an activeprimary
CPICH, i.e. replacea cell.
< !--[if !supportLists]--> e1d: change of best cell.
< !--[if !supportLists]--> e1e: a Primary CPICHbecomes better than an absolutethreshold.
< !--[if !supportLists]--> e1f: a Primary CPICHbecomes worse than an absolutethreshold.
< !--[if !supportLists]-->116.What are event 2a-2d and 3a-3d?
Events 2a-2d are for inter-frequency handover measurements and events 3a-3d are for IRAT handover
measurements.
< !--[if !supportLists]--> e3a:the UMTS cell quality has moved below a threshold and a GSM cell
quality had moved above a threshold.
< !--[if !supportLists]--> e3b: the GSM cell quality has moved below a threshold.
< !--[if !supportLists]--> e3c:the GSM cell quality has moved above a threshold.
< !--[if !supportLists]--> e3d: there was a change in the order of best GSM cell list.
< !--[if !supportLists]-->117.What may happen when there’s a missing neighbor or an incorrect
neighbor?
< !--[if !supportLists]--> Access failureand handover failure:may attempt to access to a wrong
scramblingcode.
< !--[if !supportLists]--> Dropped call:UE not awareof a strong scramblingcode,strong
interference.
< !--[if !supportLists]--> Poor data throughput.

< !--[if !supportLists]--> Poor voicequality.
< !--[if !supportLists]-->118.What can we try to improve when access failure is high?
When access failureishigh we can try the followingto improve RACH performance:
< !--[if !supportLists]--> IncreasemaximumUE transmitpower allowed:
Max_allowed_UL_TX_Power.
< !--[if !supportLists]--> Increasepower quickly:power_Offset_P0.
< !--[if !supportLists]--> Increasenumber of preambles sent in a given preamble cycle:
preamble_Retrans_Max.
< !--[if !supportLists]--> Increasethenumber of preamble cycles:max_Preamble_Cycle.
< !--[if !supportLists]--> Increasenumber of RRC Connection Request retries: N300.
< !--[if !supportLists]-->119.What are the conditions you typically set to trigger IRAT handover?
RSCP and Ec/Io areused to trigger IRAT handover:
< !--[if !supportLists]--> RSCP ≤ -100dBm.
< !--[if !supportLists]--> Ec/Io ≤ -16dBm.
< !--[if !supportLists]-->120.What are the typical KPIs you use to measure a network and what
criteria?
< !--[if !supportLists]--> Access failurerate(≤ 2%).
< !--[if !supportLists]--> Call setup time (CS: over 95% of the time < 6-second for mobile-to-PSTN, 9-
second for mobile-mobile. PS: over 95% of the time< 5-second).
< !--[if !supportLists]--> Dropped call rate(≤ 2%).
< !--[if !supportLists]--> BLER: over 95% of the blocks ≤2%.
< !--[if !supportLists]--> Average DL/UL throughput for PSD: 210kbps for loaded, 240kbps for
unloaded.
< !--[if !supportLists]-->121.What is the typical UE transmit power?
Varies - most of the time below 0dBm.
< !--[if !supportLists]-->122.Have your used Ericsson TEMS? If so:

< !--[if !supportLists]--> Do you know how to create command sequence?
< !--[if !supportLists]--> Whatarethe call sequences you typically have? CS longcall,CS shortcall,
PSD call,etc.
< !--[if !supportLists]--> Whatarethe typical commands you have for CS and PS call?
< !--[if !supportLists]--> Do you regularly stop and restart a new log file? Why and when to stop and
starta new file?
< !--[if !supportLists]--> How do you stop a logfile? Stop command sequence first,wait and make
sure all equipment arein idlemode before stop logging.
< !--[if !supportLists]-->123.Did you work on neighbor prioritization?
< !--[if !supportLists]-->124.What is the typical event sequence of IRAT Handover from 3G to
2G
< !--[if !supportLists]--> Event 2d –entering into compressed mode – measurement of 2G candidates
– Event 3a –Verification of 2G resources – Handover from UTRAN Command from 3G RNC to UE
< !--[if !supportLists]-->125.What are the possible causes for an IRAT Failure?
< !--[if !supportLists]--> Missing2Grelations
< !--[if !supportLists]--> Non availability of 2G Resources
< !--[if !supportLists]--> Poor 2G Coverage
< !--[if !supportLists]--> Missing3GRelations
< !--[if !supportLists]-->126.What is Paging Success Ratio? What is the typical PSR that you
have seen in a UMTS network?
< !--[if !supportLists]--> PSR – PagingResponses to the Paging Attempts
< !--[if !supportLists]--> About 90%
< !--[if !supportLists]-->127.What are the possible causes for a lower PSR?

< !--[if !supportLists]--> Non-continuous RF Coverage – UE going in and out of coverage area
frequently
< !--[if !supportLists]--> Very High‘Periodic Location Update Timer’ – Keeping UEs in VLR longtime
after it moved out of coverage
< !--[if !supportLists]--> Lower PagingChannel Power
< !--[if !supportLists]--> Access Channel Parameter Issues
< !--[if !supportLists]--> Delayed Location Update when crossingthe LA / CN Boundaries
< !--[if !supportLists]-->128.What are the possible causes for a Drop Call on a UMTS network?
< !--[if !supportLists]--> Poor Coverage (DL / UL)
< !--[if !supportLists]--> PilotPollution / PilotSpillover
< !--[if !supportLists]--> MissingNeighbor
< !--[if !supportLists]--> SC Collisions
< !--[if !supportLists]--> Delayed Handovers
< !--[if !supportLists]--> No resource availability (Congestion) for Hand in
< !--[if !supportLists]--> Loss of Synchronization
< !--[if !supportLists]--> FastFading
< !--[if !supportLists]--> Delayed IRAT Triggers
< !--[if !supportLists]--> HardwareIssues
< !--[if !supportLists]--> External Interference
< !--[if !supportLists]-->129.A UE is served by 2 or 3 SC in AS. It is identifying a SC from 3rd tier,
Stronger and meetsthe criteria for Event1a or Event1c. But SHO did not happen because of missing neighbor
relations? How do you optimize this issue?
< !--[if !supportLists]--> Study the Pilotspillover fromthe 3rd Tier SC and control its coverage

< !--[if !supportLists]--> Even after controllingthe coverage, if the spillover is there,Add the
neighbor.
< !--[if !supportLists]-->130.A UE is served by 2 SC in AS, a SC is coming in to Monitored Set and
Event1a is triggered. But UE is not receiving Active Set Update from NodeB and the call drops. What could be
possible causes for this drop?
< !--[if !supportLists]--> Delayed Handover
< !--[if !supportLists]--> Loss of Synchronization
< !--[if !supportLists]--> FastFading
< !--[if !supportLists]--> PilotPollution / Spillover issues
< !--[if !supportLists]-->131.What is Hard Handover in UMTS? When will it happen?
< !--[if !supportLists]--> Hard Handover in UMTS is a break before make type Handover
< !--[if !supportLists]--> Itcan happen in the inter RNC boundaries where there is no Iur link.
< !--[if !supportLists]-->132.What is the typical Call Setup Time for a 3G UE to 3G UE Call? What
are the possible RF related causes for a delayed CST in this type of call?
< !--[if !supportLists]--> 6 to 9 seconds
< !--[if !supportLists]--> MultipleRRC Attempts (UE is on poor coverage – need more than Access
Attempt)
< !--[if !supportLists]--> Delayed Page Responses
< !--[if !supportLists]--> High Load on Paging and/or Access Channel
< !--[if !supportLists]--> Paging/ Access Parameters

< !--[if !supportLists]-->133.What is Soft Handover Overhead? What is the typical value in
UMTS network?
< !--[if !supportLists]--> SoftHandover Overhead is calculated in two ways.1) Average Active Set
Size – Total Traffic / Primary Traffic.2) Secondary / Total Traffic
< !--[if !supportLists]--> Typical Values arelike1.7 (Avg Active Set Size) or 35% (Secondary / Total )
< !--[if !supportLists]-->134.What will happen to the Soft Handover Overhead when you apply
OCNS on the network? And Why?
< !--[if !supportLists]--> With OCNS, the interference (load) increases.This leads to reduction in
Ec/Io of a Pilot,which reduces the pilotspillovers.Reduction in PilotSpillover will reducethe Soft Handover
Overhead.
< !--[if !supportLists]-->135.What are the possible causes for an Access Failure in UMTS?
< !--[if !supportLists]--> MissingNeighbors
< !--[if !supportLists]--> Poor Coverage
< !--[if !supportLists]--> PilotPollution / Spillover
< !--[if !supportLists]--> Poor Cell Reselection
< !--[if !supportLists]--> CoreNetwork Issues
< !--[if !supportLists]--> Non –availability of resources.Admission Control denies
< !--[if !supportLists]--> HardwareIssues
< !--[if !supportLists]--> Improper RACH Parameters
< !--[if !supportLists]--> External Interference

< !--[if !supportLists]-->136.(FOR ERICSSON EXPERIENCED) What is RTWP? What is the
significance of it?
< !--[if !supportLists]--> Received Total Wide-band Power
< !--[if !supportLists]--> Itgives the Total Uplink Power (Interference) level received at NodeB
< !--[if !supportLists]-->137.(FOR ERICSSON EXPERIENCED) What is the System Reference Point
at which all the Power Levels are measured in Ericsson NodeB?
< !--[if !supportLists]--> System Ref Pointfor E/// NodeB is atthe output of TMA (Between TMA and
Antenna)
< !--[if !supportLists]-->138.What are the typical values for ‘reportingrange1a’ and
‘reportingrange1b’?
< !--[if !supportLists]--> 3 dB and 5 dB respectively.
< !--[if !supportLists]-->139.What will be the impact when you change ‘reportingrange1a’ from
3 to 4 dB and‘timetotrigger1a’ 100 to 320 ms, without changing any other parameters?
< !--[if !supportLists]--> Reduction in number of Event1a
< !--[if !supportLists]--> Delayed Event1a trigger
< !--[if !supportLists]--> Reduction in Average Active Set Size
< !--[if !supportLists]--> Delay in Event1a could increaseDL interference, which could lead to a drop
call or increasein Average Power Per User (reduction in cell capacity)
< !--[if !supportLists]-->140.What is Admission Control?

< !--[if !supportLists]--> Admission Control isan algorithmwhich controls the Resource Allocation
for a new call and additional resourceallocation for an existingcall. Incase,if a cell is heavily a loaded and enough
resources in terms of power, codes or CEs are not available,admission control denies permission for the additional
resourcerequirement.
< !--[if !supportLists]-->141.What is Congestion Control?
< !--[if !supportLists]--> Congestion Control monitors the dynamic utilization of specific cell
resources and insures thatoverload conditions do not occur. If overload conditions do occur,Congestion Control
will immediately restrictAdmission Control fromgrantingadditional resources.In addition,Congestion Control will
attempt to resolvethe congestion by either down switching,or terminating existingusers.Oncethe congestion is
corrected, the congestion resolution actions will cease,and Admission Control will beenabled.


< !--[if !supportLists]-->142.What is the maximum number of Channelization Codes that can be
allocated for HS, as per 3GPP standard?
< !--[if !supportLists]--> 15 codes of SF 16.

< !--[if !supportLists]--> 
< !--[if !supportLists]-->143.What is‘Code Multiplexing’ in HSDPA?
< !--[if !supportLists]--> SharingtheHS Channelization Codes among more than one HS users within
the 2ms TTI period.
< !--[if !supportLists]-->144.(FOR ERICSSON EXPERIENCED) In Ericsson System, how is the
Power allocated for HSDPA>
< !--[if !supportLists]--> Power unutilized by R99 PS, CS and Comman Channels,is used for HS (PHS =
Pmax - hsPowerMargin - Pnon-HS)
< !--[if !supportLists]-->145.What are Events that can trigger the HSDPA Cell Change?
< !--[if !supportLists]--> Event 1d HS –Change of Best Cell in the Active Set
< !--[if !supportLists]--> Event 1b or Event 1c – Removal of the Best Cell from the Active Set
< !--[if !supportLists]-->146.How is typically the Call Setup Time of a CSV call calculated in
UMTS using L3 messages?
< !--[if !supportLists]--> CST is calculated as the time difference between ‘Alerting’ and the firstRRC
Connection Request (Call Initiation) messages.
GSM,WCDMA,RF ,RF Optimization Interview Objective
Question
Level 2-3 NPO Questions
(RF Planning & Optimisation Engg)
In the followingquestions, please select one alternative which you think is the best answer for the
particular question.

Q1. SMS broadcast is done over which channel
1. SDCCH
2. BCCH
3. TCH
4. 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 followingcomment 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 defineshow 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 fieldstrength 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 betweentwo differentMSCs
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 followingKPI
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 followingis 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 designedto control the traffic load of a frequency hopping radio network in which frequenciesare
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 followingis 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. Direction of Magnetic Field
2. Direction of Electric Field
3. Direction of Electromagnetic Field
4. None of Above.
Q15 Which one is correct for TMA, TMB and Repeater?
1. AmplifiesU/L, AmplifiesD/L, and Amplifiesboth.
2. AmplifiesD/L, AmplifiesU/L, and Amplifiesboth.
3. AmplifiesU/L, AmplifiesD/L, and AmplifiesU/L.
4. AmplifiesU/L, AmplifiesD/L, and AmplifiesD/L.
Q16 Define Beam width of Antenna?

1. Angular distancebetween the points on two oppositesides of the peak direction where the radiation
intensity drops to the 1/2 of the peak intensity.
Q17 From which technique we cancel the effectof Rayleigh Fading?
1. Antenna Hoping.
2. Frequency Hoping.
3. Antenna Diversity.
4. MAIO.
Q18 If HLR=5 Millionsubs, VLR/HLR=0.7,mErl/Sub=30.Then how much Capacity is required to cater
the subscriber in RF for 70% utilizedNetwork.
1. 150 K Erl
2. 300 K Erl
3. 135 K Erl
4. 165 K Erl
Q19 Electrical Tilt antenna limitscoverage through?
1. Tilting of Dipoles.
2. Inserting Phase Shift.
3. Inserting attenuation.
4. None of the above.
Q20 Which Antenna has the highest front to back Ratio?
1. Loop
2. Yagi
3. Dipole
4. Parabolic

Q21 Select relation between forward power and ReflectedPower if load is not connected?
1. VSWR=1
2. VSWR=∞
3. VSWR=0
4. 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 mobilitymanagement states in GPRS?
1. Idle,Standby,Ready
2. Dedicated,Standby,Ready
3. Idle,Dedicated,Standby
4. None of above
Q24. Which modulation is used for EDGE above MCS-4
1. QPSK
2. GMSK
3. 8PSK
4. 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. System Info 1, 2, 3.
2. System Info 1, 2, 3,4,13.
3. System Info 5, 6.
Q28 Freq used in Uplink of Satellite communication is higher while in GSM it is lower. Why?
1. Loss α freq.
2. Loss α 1/freq.
3. Loss α sqr(freq)
Q29 AMR is used to improve?
1. SQI
2. Downlink quality.
3. Uplink Quality
4. 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.
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 followingare true?
1. Type 1 Paging: can address up to 2 mobilesusing 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 mobilesusing 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 releasesthe
source cell.
3. MS gets paging message from the target and repliesit on its RACH and gets TCH allocated.
4. MS gets paging message from the target and repliesit on its RACH and gets SDCCH
allocated.
Q34 If E-RACH is used then which of the followingis true?
1. GSM range will increase beyond 35Km
2. It will increase no of RACH channels and release congestion on RACH.
3. SDCCH assignment will improve.
4. All above are false.
Q35 In dedicated mode the BTS receives handover command on?

1. TCH
2. SDCCH
3. SACCH
4. FACCH
Q36 The duration of a single timeslotis?
1. 4.615 ms
2. 1250 ms
3. 0.577 ms
4. 156.25 ms
Q37 Modulation used in GSM radio interface is?
1. Phase shift keying (PSK)
2. Gaussian Minimum shift Keying(GMSK)
3. Frequency modulation.
4. 8PSK.
Q38 TIE stands for?
1. Terminal Equipment identifier
2. Transcoder Input Erlang
3. TRX identifierfor Edge TRX
Q39 As per GSM Standard in case of frequency hopping the C/I value should be at least?
1. 3 dB
2. 6 dB
3. 9 dB
4. 12 dB

Q40 In inter BSC handover the handover is controlled by?
1. GMSC
2. MSC
3. Source BSC
4. Target BSC
Q41 The maximum no of neighbors that can be definedwith a cell is?
1. 8
2. 16
3. 32
4. 64
Q42 The permissible value of VSWR for feedercable is?
1. < 1.3
2. >1.3
3. > 1
4. <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. Time Synchronized Channel
2. Temporary subscriber code
3. Transcoder Signaling Controller
4. Training Sequence Code
Q45 If Cell bar is set to “yes” on a cell then
1. It will reject new calls as well as handover calls
2. It will reject new call assignment but will receive calls by Handover
3. It will reject Handover but allow new call to come
4. The BTS will go into locked state.
Q46 DAP stands for
1. Dual Abis pool
2. Dynamic Allocation protocol
3. Dynamic AbisPool
Q47 Who can initiate the GPRS detach
1. The MS only
2. The SGSN only
3. Both the MS and the SGSN
Q48 The mapping of logical name/Host name to IP addresses in the GPRS network is done by
1. Border Gateway
2. SGSN
3. GGSN
4. DNS

Q49 Where is the mobility management context establishedin GPRS
1. In the MSC
2. In the SGSN
3. In the GGSN
4. All of the above
Q50 Which layer uses the functionality of Uplink State Flag (USF)?
1. RLC Layer
2. Physical Layer
3. MAC Layer
4. All of the above
Q51 How many TDMA frames are there in a PDCH multiframe?
1. 51
2. 52
3. 26
4. 8
Q52 Which coding scheme does not use Forward Error Correction (FEC)?
1. CS-1
2. CS-2
3. CS-3
4. CS-4
Q53 Which new area is definedin GPRS compared to GSM?
1. Location Area
2. Routing Area
3. Both a and b

Q54 Which layer is responsible for segmentation and reassembly of LLC PDUs and backward error
correction (BEC) procedures?
1. Physical Layer
2. Application Layer
3. RLC Layer
4. MAC Layer
Q55 Which coding scheme has adopted the same coding as used for SDCCH?
1. CS-1
2. CS-2
3. CS-3
4. CS-4
Q56 What is the single timeslotdata rate for coding scheme CS-2
1. 7.8 Kbit/s
2. 10.4 Kbit/s
3. 13.4 Kbit/s
4. 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. 6
2. 4
3. 2
4. 8
Q59 During conference call which channel is used to establish another call-
1. SACCH
2. SDCCH
3. FACCH
4. TCH
Q60 What is Duplex spacing.
1. Difference betweenfirst frequency of Uplink and last frequency of Downlink.
2. Difference betweenfirst frequency of Downlink and first frequency of Uplink.
3. Difference betweenlast frequency of Downlink and first frequency of Uplink.
Q61 What does MSRN stands for ….
1. Mobile Station Registration Number
2. Mobile System Registration Number
3. Mobile Station Roaming Number
4. Mobile Station Register Number.
Q62. If my MCC=404, MNC=05, LAC=100, CI = 14011, then what will be CGI for same??
1. 4040510014011
2. 404056436BB
3. 4040514433273
4. 4040510033273
Q63. Which information is there in Handover Access Command in Layer 3 Message?

1. BCCH & BSIC of Source
2. BCCH & BSIC of Target
3. Handover Reference Value
4. 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 fallsunder 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 helpsto 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 eventhough having poor C1?
1. CRO
2. TEO
3. Penalty Time
4. None of above.
Q76. Common BCCH feature is implementedin network, then which feature will helpto access the
secondary freq. spectrum directly?
1. DR
2. DADB
3. DADL
4. 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 Familiesare there?
1. 1
2. 2

3. 3
4. 4
Q83. Which is / are the main factors affecting the Radio Accessibilityfor TBF in UL/ DL?
1. Coverage
2. Capacity
3. Interference
4. All of above.
Q84. Which parameter setting can helpto 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 fulfilledbyDynamic 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 differentTRXs 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 followingchannels which one is common channel?
1. AGCH
2. SACCH
3. TCH-FR
4. FACCH
Q95. Out of followingchannels which one is the answer to RACH?
1. SDCCH
2. AGCH
3. FACCH
4. SACCH
Q96. In Air-interface TDMA time-slotmeans 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
4. Paging message for >4 mobiles
Q102. Out of followingwhich 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 followingwhich element/sin 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 followingwhich one is a passive device?
1. Repeater
2. Cross Polar Antenna
3. TMA (Tower Mount Amplifier)
4. TRX
Q112. Out of followingwhich 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. 1-7
2. 0-2
3. 0-7
4. None of Above.
Q115. What are the contents of authentication triplets?
1. A3,A5,A8

2. SRES,RAND,Kc
3. RAND,A3,A8
4. 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.
Q117 .Which of the followingfunctions is not done by SDCCH CHANNEL:
1. Authentication
2. Transmission of short messages
3. Adaptive power control information from BTS to MS only
4. Assignment of traffic channel to MS.
Q118 How many TS can be used at the most with HSCSD?
1. 2
2. 4
3. 6
4. 8
Q119 What should be the value of C/I when you are in hopping mode?
1. Above 9
2. Above 12
3. Less than 9
4. All of the above are correct
Q120 Which value of level and quality should be considered for analysis in a DT log

1. Full
2. Sub
3. Both
4. None of the above is correct.
Q121 What are the coding schemes observerd in UL/ DL after implementingEDGE in your Network:
1. CS1-CS4
2. MCS1-MCS6
3. MCS5-MCS9
4. MCS1-MCS9
Q122 What does DAP stand for?
1. Dynamic AbisPool
2. Dynamic Access Pool
3. Dynamic Access Protocol
Q123 How many codec’s can be definedfor AMR HR
1. 5
2. 2
3. 6
4. 4
Q124 How many TRX’s can be accommodated max on a single E1 where DAP pool is assigned for 4
TS in a Ultra site
1. 12
2. 16
3. 18
4. 24

Q125 How much traffic will be offered by a sector having 4 TRX with GOS of 2%
1. 24Erlangs
2. 21.03Erlangs
3. 23.56Erlangs
4. 22.12 Erlangs
Q126 Which ND report would you refer in order to find the discrepancy for Handovers?
1. Report 163
2. Report 166
3. Report 153
4. Report 208
Q127 On what basis would an optimizer decide whether the site serving is overshooting:
1. On the basis of TA
2. From ND report 232
3. Physically verifyingwhether the cell is having up tilt
4. All of the above
Q128 BBH is generally implementedwhere:
1. For dense network
2. For small capacity network
3. For cells where tight frequency reuse is required
Q129 In case of Directed retry HO:

1. HO is performed from TCH of serving to TCH of Adjacent cell
2. HO is performed from SDCCH of serving to TCH of adjacent cell
3. HO is performed from TCH of Serving to SDCCH of adjacent cell
4. HO is performed from SDCCH of serving to SDCCH of adjacent cell
Q130 Which alarm indicates the TRX faulty operation in the system:
1. 7601
2. 7602
3. 7725
4. 7745
Q131 C/I estimation during a DT can be done in:
1. U/L
2. D/L
3. Both A&B
4. Cannot be estimated.
Q132 Which is the unique feature in TEMS for analsing speech quality:
1. Rx qual Full
2. Rx Qual Sub
3. SQI
4. Rx Qual.
Q133 Drop calls due to Handovers can be caused basically due to:
1. Neighbors with Co-BSIC
2. Neighbor with Co-BCCH
3. Neighbors with Co-BCCH and Co-BSIC
4. All of the above.

Q134 Consider a cell where the no calls are happening, the probable causes would be
1. Wrong definitionof LAC,CI
2. DMAX=0
3. Only A is correct
4. Both A&B are correct.
Q135 What should be the value of RxlevAccess min set:
1. -47dbm
2. -110dm
3. -65dbm
4. -85dbm
Q136 What would be the output of a cell with parameter setting as MstxPwrmax=0db,BsTxPWrMax
=30db
1. Cell will carry max.no of calls
2. Cell will carry very fewcalls
3. Cell will not be latched
4. Cell with a correct parameter setting.
Q137 What would be the power loss after using a combiner in a sector:
1. -2db
2. -1db
3. -3db
4. -4db
Q138 What will happen in case where GTRX=Y(Non Edge TRX),EDGE=Y:
1. TRX will be unlocked
2. System will not allow the TRX to be unlock

3. TRX will go in Block state
4. 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 logicallyrepresent how many Trx:
1. 1
2. 2
3. 3
Q141 ‘Booster ’ becomes a solution in case of :
1. Capacity
2. Coverage
3. A & B Both
Q142 Recommended value of ITCF is :
1. 2
2. 0
3. 1
4. 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 findthe discrepancy for Handovers?
5. Report 163
6. Report 166
7. Report 153
8. Report 208
Q145.On what basis would an optimizer decide whether the site serving is overshooting:
5. On the basis of TA
6. From ND report 232
7. Drive test logs
8. All of the above
Q146.Which ND report would give you the total payload for GPRS:
5. 232
6. 208
7. 228
8. 226.
Q147 What is a Command to check active alarms on bts:
1. ZERO
2. ZEQO
3. ZEOL
4. ZELO
Q148 Value of BSC Timers can be checked by command:
1. ZEFO
2. ZEDO
3. ZEHO
4. ZEGO

Q149 ND Report 71 Tells:
1. Adjacencies having highest success rate
2. Adjacencies having highest failure rate
3. All adjacencies
Q150.Which report gives value of dedicated data time slots:
1. 051
2. 053
3. 061
4. 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 Which ND report gives detailedanalysis of a cell?
1. 204
2. 216
3. 186
4. 226

Q154 In which ND report we can see hourly Traffic Profile for a cell?
1. 180
2. 181
3. 182
4. 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 Which counter shows DL multislotassignment in percentage?
1. msl_13
2. msl_14
3. msl_15a
4. 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 TRX’s 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 TRX’s can be handled by 1 BB2F Card in Ultra Site BTS?
1. 2
2. 3
3. 4
4. 6
Q168. Which of the followingBTS Type do not have combiner in-builtin 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 deletioncounts for cell level?
1. 180
2. 181
3. 182
4. 186
Q171 Out of following,which is true as per NSN Specification?
1. CDED<=CDEF
2. CDED>CDEF
3. CDED=CDEF+CMAX
4. 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 Which report shows Intra Cell Handover Statistics?
1. 150
2. 153
3. 154
4. 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 Which BTS Type does not support Rx Diversity (RDIV) parameter?
1. Flexi Edge BTS
2. Ultra BTS
3. Metro BTS
4. Talk Family BTS
Q176 In case of EDGE which of the followingCS offers highest coverage?
1. MCS 1
2. MCS 9
3. MCS 5
4. CS 1
Q177 Which ND Report shows Trx vise quality distribution?
1. 180
2. 269
3. 196
4. 169
Q178 ND Report gives radio timeslotconfiguration?
1. 111
2. 222
3. 121
4. 051
Q179 Noise separation feature can be implementedin?
1. TCSM
2. BSC 3i
3. Flexi BTS
4. TRX

Q180 Which of the followingis 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. Possibilityof full international roaming in any country
3. Better speech quality
4. Fully digitizedswitching exchange
Q181 which of the followingis parameter affecting cell sites while planning the network
1. Antenna height
2. MS power
3. BTS Power
4. None Of Above
Q182 What is E interface?
1. MSC-MSC
2. MSC-VLR
3. MSC-HLR
4. HLR-VLR
Q183 In GSM which type of handover occurs?
1. Hard
2. Soft
3. Both of the above
4. Make before break
Q184 Choose the correct bit pattern of a flag in LAP-D format ?
1. 01111110
2. 11111111
3. 10101010.
4. 01010101.
Q185 Mobile identityis a part of?

1. Physical layer Info
2. Lap-D Info
3. BSSMAP Info
4. 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 istrue?
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 betweenBSC 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 followingis notan 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 efficientthan 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 filteringat 13Kbits/s
Q194. Authentication verificationis carried out in
a) HLR
b) MSC
c) VLR
d) Authentication Centre
Q195. No calls initiatingin a cell, handover traffic is present
1. wrong neighbor defined
2. CGI creation problem
3. Same BCCH Allocated in neighbor
4. None of above
Q196. Which of the followingfacility 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. At least λ/4 separated
2. At least λ/10 separated
3. 0 distance
4. None of above
Q198. Which of the followingis supported by remote tune combiner?
1. BB Hopping
2. RF Hopping
3. Cyclic Hopping
4. All of above
Q199. Which of the followingis affecting SDCCH capacity on Abis Interface?
1. TRX Signaling Size
2. No of TCH in sector
3. EDAP Pool
4. 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
What is LTE?
LTEi (Long Term Evolution) is initiated by 3GPPi to improve the mobile phone standard to cope with future
technology evolutions and needs.
What is goal of LTE?

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