 |
MNA810S - MOBILE NETWORKS AND ARCHITECTURES - 1ST OPP - JUNE 2024 |
|
|
1 Page 1 |
▲back to top |
nAmlBIA unlVERSITY
OF SCIEnCE Ano TECHnOLOGY
Faculty of Computing and Informatics
Department of Computer Science
QUALIFICATION:BACHELOROF COMPUTERSCIENCEHONOURS
QUALIFICATIONCODE: 08BCHC
LEVEL:8
COURSE:MOBILE NETWORKSAND
ARCHITECTURES
DATE:JUNE2024
COURSECODE: MNA810S
SESSION: 1
DURATION: 3 HOURS
MARKS: 100
FIRSTOPPORTUNITYEXAMINATION QUESTION PAPER
EXAMINER(S} PROFDHARM SINGHJAT
MODERATOR: DR LINOH MAGAGULA
THIS QUESTIONPAPERCONSISTSOF THREEPAGES
(Excluding this front page)
INSTRUCTIONS
1. Write clearly and neatly.
2. Write all your answers in the answer booklet provided.
3. Number the answers clearly.
4. This paper consists of two sections; Section A and B.
5. Answer ALLquestions in section A.
6. Answer any 3 questions in section B.
7. Begin each section on a new page.
8. Marks/scores per question are given in [ ].
9. Do not use or bring into the examination venue books, programmable calculators,
mobile devices and other material that may provide you with unfair advantage. Should
you be in possession of one right now, draw the attention of the examination officer
or invigilator.
10. NUST'sexamination rules and regulations apply.
|
|
2 Page 2 |
▲back to top |
SECT/ONA
[40Marks]
Thissection contains TWO questions.
Attempt All questions.
Ql Choose the correct answer for each of the following multiple-choice questions.
[20 marks,2 marksfor each]
(i). Five channels, each with a 100-kHz bandwidth, are to be multiplexed
together. What is the minimum bandwidth of the link if there is a need for
a guard band of 10 kHz between the channels to prevent interference?
A. 550 kHz
B. 540 kHz
C. 560 kHz
D. 500 kHz
(ii). What is the name of the database that stores subscriber information and
the services that the subscriber is eligible to use under an MSC?
A. MSC
B. Aue
C. EIR
D. HLR
(iii). In LTEE-UTRANFrame Structure, the number of Time -slots present in
one Sub-Frame is:
A. Five
B. Three
C. Four
D. Two
(iv). 3G W-CDMA is also known as
A. UMTS
B. DECT
C. DCS-1800
D. ETACS
(v). What is the interface between NodeB and RNCin a WCDMA network?
A. Luc
B. Lub
C. Lud
D. Lue
(vi). Which of the following is a component of a 3G network architecture?
A. User Equipment (UE)
B. Radio Access Network (RAN)
C. Core Network
|
|
3 Page 3 |
▲back to top |
D. All the above options
(vii). Which of the following memory device stores information such as
subscriber's identification number in GSM?
(viii).
A. Register
B. Flip flop
C. SIM
D. SMS
What is a cluster in a cellular system?
A. Group of frequencies
B. Group of cells
C. Group of subscribers
D. Group of mobile systems
(ix). Which of the following multiple access techniques allocates different
time slots for the different users?
A. TDMA
B. CDMA
C. FDMA
D. FGMA
(x). In which layer do Wireless LANs implement security measures?
A. System Layer
B. Data Link Layer
C. Sub Layer
D. Multi-Layer
Q2 (i). Why is a Temporary Mobile Subscriber Identity (TMSI) required when we [4]
have an international mobile subscriber identity (IMSI)?
(ii). Describe frequency division multiplexing in wireless communication.
[4]
(iii). Explain how CSMA/CA solves the Hidden and exposed terminal problems. [4]
(iv). State two functions of the eNB in E-UTRANsystems.
[4]
(v). State two functions of the Mobility Management (MM) protocol in UMTS. [4]
SECTIONB {60Marks]
This section contains FOUR questions
Attempt any THREEquestions.
Q3 a)
A cellular system with a total bandwidth of 15 MHz uses 10 kHz simplex
channels to provide full duplex voice and control channels for 12 cell reuse
patterns. 1 MHz of the total bandwidth is allocated for control channels.
(i) Calculate the total available channels.
[4]
(ii) Determine the number of control channels.
[3]
(iii) Calculate the number of voice channels per cell.
[3]
2
|
|
4 Page 4 |
▲back to top |
b) Assume a spectrum of 480 kHz is allocated over a base frequency for
communication between stations A and B.
{i)
Divide the entire bandwidth into four sub-bands.
[4]
{ii) Why do we divide the entire bandwidth into sub-bands?
[3)
{iii) Should we allocate a guard band? Why?
[3)
Q4 a)
b)
In LTEE-UTRANFrame Structure
{i). How many samples per second is full-duplex system in LTEFDD?. [2)
{ii). How many Sub-frames are present in a single Frame-Structure, and
what is the size of each Sub-Frame in the time domain?
[4]
{iii). How many time slots are present in a Sub-Frame?
[2]
{iv). What is Cyclic Prefix {CP}in a Frame-Structure?
[2]
(v). How many OFDM symbols are available in 1 time slot in Normal CP [2]
and Extended CP?
With the help of an appropriate diagram, explain the basic steps of
[8]
Mobile originated call (MOC} to a fixed network.
Q5 a)
b}
With the help of an appropriate diagram, discuss how Encryption is [8]
achieved in a GSM network.
In a full-rate TDMA system used in United States Digital Cellular (USDC}IS-
54 standard, the
• duration of a TDMA voice frame = 40ms
• number of time slots in a frame= 6
• number of bits in a voice frame= 1944
• Number of bits in guard band ==6
Calculate
i) the duration of a time slot of a voice frame
[3]
ii) the number of bits in a time slot of a voice frame
[3]
[3]
iii) the duration of a bit
[3]
iv) the duration of guard time
Q6
Discuss the following subsystems of GSM Architecture:
(i) the mobile station {MS),
[5]
{ii) the base station sub system (BSS),
[5]
(iii) the network and switching subsystem {NSS),and
[5]
(iv) the operation subsystem {OSS).
[5]
GOOD LUCK/
3