 |
MNA810S - MOBILE NETWORKS and ARCHITECTURES - 2ND OPP - JULY 2022 |
|
|
1 Page 1 |
▲back to top |
nAmlBIA unlVERSITY
OF SCIEnCE Ano TECHnOLOGY
Faculty of Computing and Informatics
Department of Computer Science
QUALIFICATION: BACHELOR OF COMPUTER SCIENCE HONOURS
QUALIFICATION CODE: 08BCHC
LEVEL: 8
COURSE: MOBILE NETWORKS AND
ARCHITECTURES
DATE: JULY 2022
COURSE CODE: MNA810S
SESSION: 1
DURATION: 3 HOURS
MARKS: 100
SECOND OPPORTUNITY/ SUPPLEMENTARY EXAMINATION QUESTION PAPER
EXAMINER(S) PROF DHARM SINGH JAT
MODERATOR: DR LINOH MAGAGULA
THIS QUESTION PAPER CONSISTS OF THREE PAGES
{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 ALL questions 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's examination rules and regulations apply.
|
|
2 Page 2 |
▲back to top |
SECT/ONA
[40Marks]
SECrtONA
[40Marks]
This section contains TWO questions.
Attempt ALLquestions.
Ql Choose the correct answer for each of the following multiple-choice questions.
[20 marks, 2 marks for each]
(i). Which of the following memory device stores information such as
subscriber's identification number in GSM?
A. Register
B. Flip flop
C. SIM
D. SMS
(ii). Which of the following is not a subsystem of GSM architecture?
A. BSS
B. NSS
C. 055
D. Channel
(iii). Which multiple accesstechnique is used by IEEE802.11 standard for
wireless LAN?
A. CDMA
B. CSMA/CA
C. ALOHA
D. None of the mentioned
(iv). What is the responsibility of MSC in a cellular telephone system?
A. Connection of mobile to base stations
B. Connection of mobile to PSTN
C. Connection of base station to PSTN
D. Connection of base station to MSC
(v). What is the shape of the cell in the cellular system?
A. Circular
B. Square
C. Hexagonal
D. Triangular
(vi). Why is the size of the cell kept small in a cellular network?
A. Increase capacity
B. Decrease capacity
C. Increased size of base station electronics
D. Slow process of handoffs
|
|
3 Page 3 |
▲back to top |
,,
{vii). What is handoff?
A. Forward channel
B. Switching technique
C. Roamer
D. Guard channel
{viii).
Which of the following is one of the disadvantages of 2G standards?
A. Short Messaging Service {SMS)
B. Digital modulation
C. Limited capacity
D. Limited Internet Browsing
{ix). Which of the following is not a standard of 3G?
A. UMTS
B. Cdma2000
C. TD-SCOMA
D. LTE
(x). If the frequency of a radio signal is 5.0 GHz, what is the wavelength of
the signal {velocity of light=3x10 8m/s)?
A. 66 meters
B. 16.3 millimeters
C. 60 millimeters
D. None of the option
Q2 {i). Explain Multi-path propagation.
[4]
{ii). Describe frequency division multiplexing techniques in wireless
[4]
communication.
{iii). Explain the hand-off mechanism in mobile communications.
[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]
Thissection contains FOUR questions
Attempt any THREEquestions.
Q3
A particular cellular system has the following characteristics: cluster size
=7, uniform cell size, user density=lOO users/sq km, allocated frequency
spectrum= 900-949 MHz, bit rate required per user= 10 kbps uplink and
10 kbps downlink, and modulation code rate= 1 bps/Hz.
2
|
|
4 Page 4 |
▲back to top |
,,
(i.) How much bandwidth is available per cell using FDD?
[5]
a)
(ii.) How many users per cell can be supported using FDMA?
[5]
(iii.) What is the cell area?
[5]
b) If the available spectrum is divided into 35 channels and TDMA is
employed within each channel:
What is the bandwidth and data rate per channel?
[5]
Q4 a)
b)
Q5 a)
b)
c)
With the help of an appropriate diagram, explain the basic steps of Mobile
terminated call (MTC) i.e., needed to connect a calling station with a (12]
mobile user when the calling station is in a different GSM network.
[Each correct steps = 1 Mark]
With the help of an appropriate diagram discuss how authentication is
achieved in a GSM network.
[8]
[Correct event in diagram = !Mark]
[Correct statements =!Mark]
Describe how CSMA/CA solves the Hidden and Exposed terminals [6]
problems.
Calculate the maximum distance between the cell site and mobile if the [4]
Guard time is 123 µsand the electromagnetic radio waves propagate at
the speed of light (c= 3x105 km/s).
Draw and explain GSM structuring of time using a frame hierarchy.
[10]
Q6 a)
b)
c)
Write three differences between UTRAN and eUTRAN?
[6]
Sketch and explain E-UTRANarchitecture.
[8]
If a total of 33 MHz of bandwidth is allocated to a particular FDD cellular [6]
telephone system which uses two 25 kHz simplex channels to provide full
duplex voice and control channels, compute the number of channels
available per cell if a system uses
(i). One-cell reuse
(ii). four-cell reuse
(iii). seven-cell reuse
GOOD LUCK!
3