INTERVIEW QUESTIONS

GSM Air Interface


1.What is the uplink frequency range for GSM?
a. 935-960MHz
b. 945-960MHz
c. 890-915Mhz
d. 880-915MHz

2. What is the Downlink frequency range for GSM?
a. 935-960MHz
b. 945-960MHz
c. 890-915Mhz
d. 880-915MHz

3.How many carriers are present in GSM?
a. 8
b. 124
c. 25
d. 16

4. How many Channels are present in each carrier?
a. 8
b. 124
c. 25
d. 16

5. What type of modulation is used in GSM?
a. GMSK
b. BPSK
c. QPSK
d. MSK

6. What is the period of 1 burst?
a. 20ms
b. 120ms
c. 0.320ms
d. 0.577ms

7. What is the spacing between each Channel?
a. 25MHz
b. 200KHz
c. 1.25MHz
d. 100KHz


8. What is the interface between the Mobile Station and BTS called?
a. Um interface
b. Abis Interface
c. A Interface
d. B Interface

9. The Channel that is used to alert the Mobile Station of an incoming call is
a. Random Access CHannel
b. Paging CHannel
c. Synchronization CHannel
d. Access Grant CHannel

10. The Channel that is used to carry all signaling information when no traffic Channel
has been allocated is
a. Random Access CHannel
b. Broadcast Control CHannel
c. Fast Associated Control CHannel
d. Stand Alone Dedicated Control CHannel

11. The Channel that is used to transfer uplink messages in response to paging
request is
a. Random Access CHannel
b. Access Grant CHannel
c. Slow Associated Common Control CHannel
d. Fast Associated Control CHannels

12. Neighboring cell information is carried on
a. Broadcast Control CHannel
b. Paging CHannel
c. Random Access CHannel
d. Slow Associated Common Control CHannel

13. Frame synchronization of the MS is done by
a. Broadcast Control CHannel
b. Paging CHannel
c. Access Grant CHannel
d. Synchronization CHannel

14. The Channel that is transmitted in burst stealing mode is
a. BCCH
b. RACH
c. FACCH
d. SDCCH



15. How many slots make up a frame?
a. 4
b. 8
c. 12
d. 16

16. How many frames make up a TCH multiframe?
a. 8
b. 16
c. 26
d. 51

17. How many frames make up a CCH multiframe?
a. 8
b. 16
c. 26
d. 51

17. What are the different broadcast control Channels?
a. Paging CHannel, broadcast control CHannel and Synchronization CHannel
b. Broadcast control CHannel, common control CHannels, random access CHannel
c. Broadcast control CHannel, synchronization CHannel and frequency correction CHannel
d. Broadcast control CHannel, access grant CHannel and random access CHannel

18. What are the various types of common control Channels?
a. Paging CHannel, broadcast control CHannel and Synchronization CHannel
b. Broadcast control CHannel, common control CHannels, random access CHannel
c. Synchronization CHannel, frequency correction CHannel and access grant CHannel
c. Paging CHannel, random access CHannel and access grant CHannel

19. What are the different dedicated control Channels?
a. Paging CHannel, broadcast control CHannel and Synchronization CHannel
b. Broadcast control CHannel, access grant CHannel and random access CHannel
c. Paging CHannel, random access CHannel and access grant CHannel
d. Stand alone dedicated control CHannel, slow associated control CHannel and fast associated control CHannel.

20. What is the spacing between an uplink and downlink carrier?
a. 1.25MHz
b. 25MHz
c. 45MHz
d. 60MHz

21. What is the basic GSM speech rate?
a. 13Kbps
b. 14Kbps
c. 15Kbps
d. 16Kbps



22. What is the basic GSM data rate?
a. 13Kbps
b. 9.6Kbps
c. 4Kbps
d. 10.2Kbps

23. A MS is said to be in dedicated mode when
a. A traffic Channel is allocated to it
b. A traffic Channel is not allocated to it

24. A traffic Channel (TCH) is always associated with
a. AGCH
b. RACH
c. PAGC
d. SACCH

25. Which of these Channels is an uplink Channel?
a. FCCH
b. RACH
c. BCCH
d. PAGCH

26. What is the speech coding algorithm used in GSM?





















GSM Protocol Architecture


1. The layer 2 protocol on the air interface is
a. LAPDm
b. LAPD
c. SCCP
d. TCAP

2. The layer 2 protocol on the Abis interface is
a. LAPDm
b. LAPD
c. SCCP
d. TCAP

3. The interface between the MSC and VLR/HLR are
a. MTP
b. BSSAP and MTP
c. TCAP and MAP
d. MAP and MTP

4.The layer responsible for the management of the radio resource management is
a. Radio Resource management layer (RR)
b. Mobility Management layer (MM)
c. Communication Control Layer (CM)

5. The layer which is responsible of handling call related supplementary services is
a. RR
b. MM
c. CM



6.The function of handovers is performed by?
a. RR
b. MM
c. CM








GSM Network Architecture

1. The network entity which is in direct contact with the Mobile Station (MS) is
d. Base Transceiver Station (BTS)
e. Base Station Controller (BSC)
f. Mobile Switching center (MSC)
g. Home location Register (HLR)

2. The network entity which is in charge of managing one or more BTS is
a. MSC
b. BSC
c. AuC
d. HLR

3. The entity which is in charge of managing the radio resources is
a. BTS
b. BSC
c. MSC
d. HLR

4. The code which identifies the Mobile Equipment is
a. Subscriber identity Module (SIM)
b. International Mobile Subscriber identity (IMSI)
c. International Mobile Equipment Identity (IMEI)
d. Temporary Mobile Subscriber Identity (TMSI)

5. The code which is used instead of IMSI for security reasons is
a. IMEI
b. TMSI
c. SIM
d. MSISDN

6. The directory number used to call up the subscribers is
a. MSISDN
b. IMSI
c. TMSI
d. IMEI

7. Both MSISDN and IMSI contain an identification of the country and the network
within the country
a. True
b. False

8. Subscriber information relevant to the to the provision of telecom services is held by?
a. MSC
b. VLR
c. HLR
d. BSC

9.What is the fucnction of the TRAU?
The TRAU is used for transcoding and rate adaptation. Basically speech on air interface is encoded as 13Kbps whereas speech on ISDN lines is standard 64Kbps. This translation from 13Kbps on air interface to 64Kbps standard ISDN rate is done by the TRAU.

10. The database which stores data related to mobile equipment is
a. AuC
b. BSC
c. EIR
d. MSC




GSM Layer 3

1. When there is no transmission taking place for a MS it is said it be in
e. Dedicated mode
f. Idle Mode
g. Handover
h. Sleep mode

2. The process in which the actual transmission on radio part is reduced to minimum during silence periods is
a. Handover Process
b. Discontinuous Reception
c. Paging Procedure
d. Discontinuous Transmission