NCS 30022101010 NCSP 2G RA OaM 2 2 Practice Exam
**Question 1. Which interface connects the Base Transceiver Station (BTS) to the
Base Station Controller (BSC) in a 2G GSM network?**
A) A‑interface
B) A‑bis interface
C) B‑interface
D) C‑interface
Answer: B
Explanation: The A‑bis (A‑b) interface carries traffic and signaling between the BTS
and BSC, using the BSSAP protocol over LAPD.
**Question 2. In the GSM TDMA frame structure, how many timeslots are
available per radio frame?**
A) 4
B) 6
C) 8
D) 12
Answer: C
Explanation: Each GSM radio frame consists of 8 timeslots, numbered 0‑7, each
576.9 µs long.
**Question 3. Which channel is used by a mobile station to receive broadcast
system information such as cell identity and network name?**
A) SDCCH
, NCS 30022101010 NCSP 2G RA OaM 2 2 Practice Exam
B) BCCH
C) TCH
D) SACCH
Answer: B
Explanation: The Broadcast Control Channel (BCCH) continuously transmits system
information to all mobiles in the cell.
**Question 4. Frequency hopping in GSM is primarily employed to:**
A) Increase data rates
B) Reduce co‑channel interference
C) Extend cell coverage
D) Enable handover
Answer: B
Explanation: Frequency hopping changes the carrier frequency each timeslot,
averaging out interference and improving link quality.
**Question 5. Which power control mechanism is used on the uplink (mobile →
BTS) in GSM?**
A) Closed‑loop power control
B) Open‑loop power control
C) Adaptive modulation
D) Dynamic bandwidth allocation
, NCS 30022101010 NCSP 2G RA OaM 2 2 Practice Exam
Answer: A
Explanation: GSM employs closed‑loop uplink power control where the BTS
commands the mobile to adjust its transmit power via the Power Control Channel
(PCCH).
**Question 6. The Grade of Service (GoS) parameter for a GSM cell is defined as
the probability that a call is:**
A) Dropped after being connected
B) Blocked during call attempt
C) Handover fails
D) Experiences low voice quality
Answer: B
Explanation: GoS measures the likelihood that a call attempt is blocked due to
insufficient traffic channels.
**Question 7. In GPRS/EDGE, the Packet Control Unit (PCU) resides in which
network element?**
A) BTS
B) BSC
C) MSC
D) SGSN
Answer: B
, NCS 30022101010 NCSP 2G RA OaM 2 2 Practice Exam
Explanation: The PCU is a functional block within the BSC that handles packet data
scheduling for GPRS/EDGE.
**Question 8. Which modulation scheme is introduced by EDGE to achieve higher
data rates compared to GPRS?**
A) GMSK
B) 8‑PSK
C) QAM
D) OFDM
Answer: B
Explanation: EDGE uses 8‑Phase Shift Keying (8‑PSK) in addition to GMSK, allowing
up to three times the GPRS data rate.
**Question 9. During a location update, the mobile station sends a **LAU**
request to the VLR. What does **LAU** stand for?**
A) Location Area Update
B) Link Access Update
C) Local Authentication Unit
D) Least Available Uplink
Answer: A
Explanation: LAU is the procedure where the UE informs the network of its new
location area.
**Question 1. Which interface connects the Base Transceiver Station (BTS) to the
Base Station Controller (BSC) in a 2G GSM network?**
A) A‑interface
B) A‑bis interface
C) B‑interface
D) C‑interface
Answer: B
Explanation: The A‑bis (A‑b) interface carries traffic and signaling between the BTS
and BSC, using the BSSAP protocol over LAPD.
**Question 2. In the GSM TDMA frame structure, how many timeslots are
available per radio frame?**
A) 4
B) 6
C) 8
D) 12
Answer: C
Explanation: Each GSM radio frame consists of 8 timeslots, numbered 0‑7, each
576.9 µs long.
**Question 3. Which channel is used by a mobile station to receive broadcast
system information such as cell identity and network name?**
A) SDCCH
, NCS 30022101010 NCSP 2G RA OaM 2 2 Practice Exam
B) BCCH
C) TCH
D) SACCH
Answer: B
Explanation: The Broadcast Control Channel (BCCH) continuously transmits system
information to all mobiles in the cell.
**Question 4. Frequency hopping in GSM is primarily employed to:**
A) Increase data rates
B) Reduce co‑channel interference
C) Extend cell coverage
D) Enable handover
Answer: B
Explanation: Frequency hopping changes the carrier frequency each timeslot,
averaging out interference and improving link quality.
**Question 5. Which power control mechanism is used on the uplink (mobile →
BTS) in GSM?**
A) Closed‑loop power control
B) Open‑loop power control
C) Adaptive modulation
D) Dynamic bandwidth allocation
, NCS 30022101010 NCSP 2G RA OaM 2 2 Practice Exam
Answer: A
Explanation: GSM employs closed‑loop uplink power control where the BTS
commands the mobile to adjust its transmit power via the Power Control Channel
(PCCH).
**Question 6. The Grade of Service (GoS) parameter for a GSM cell is defined as
the probability that a call is:**
A) Dropped after being connected
B) Blocked during call attempt
C) Handover fails
D) Experiences low voice quality
Answer: B
Explanation: GoS measures the likelihood that a call attempt is blocked due to
insufficient traffic channels.
**Question 7. In GPRS/EDGE, the Packet Control Unit (PCU) resides in which
network element?**
A) BTS
B) BSC
C) MSC
D) SGSN
Answer: B
, NCS 30022101010 NCSP 2G RA OaM 2 2 Practice Exam
Explanation: The PCU is a functional block within the BSC that handles packet data
scheduling for GPRS/EDGE.
**Question 8. Which modulation scheme is introduced by EDGE to achieve higher
data rates compared to GPRS?**
A) GMSK
B) 8‑PSK
C) QAM
D) OFDM
Answer: B
Explanation: EDGE uses 8‑Phase Shift Keying (8‑PSK) in addition to GMSK, allowing
up to three times the GPRS data rate.
**Question 9. During a location update, the mobile station sends a **LAU**
request to the VLR. What does **LAU** stand for?**
A) Location Area Update
B) Link Access Update
C) Local Authentication Unit
D) Least Available Uplink
Answer: A
Explanation: LAU is the procedure where the UE informs the network of its new
location area.
