MC November, 2011 Set4

IV B.Tech. I Semester Regular Examinations, November, 2011
MOBILE COMPUTING
(Common to Computer Science & Engineering, Information Technology and Electronics &
Computer Engineering)
Time: 3 Hours Max Marks: 80
Answer any FIVE Questions
All Questions carry equal marks
*******
1. a) What are the limitations of a GSM cell in terms of diameter and capacity (voice, data)
for the traditional GSM, HSCSD, GPRS? How can the capacity be increased?
b) What are the reasons for the delays in the GSM system for packet data traffic?
Distinguish between circuit switched and packet-oriented transmission.
2. a) What is the reason for the failure of MAC schemes in wireless networks? What is
done in wired networks to avoid this effect?
b) Explain about FDMA.
3. a) What is IP packet delivery? Explain it.
b) What is reverse tunneling? What additional routes do packets take if reverse tunneling
is required?
4. a) Compare the different types of transmission errors that can occur in wireless and wired
networks. What additional role does mobility play?
b) Explain mobile TCP. How does a supervisory host send TCP packets to the mobile
node and to a fixed TCP connection? Give the advantages and disadvantages of
mobile TCP.
5. a) Explain about power-aware computing.
b) Explain stateless and stateful cache invalidation mechanisms.
6. a) Describe push-based data-delivery mechanism. What are the advantages and
disadvantages of push-based data dissemination?
b) Explain the following selective tuning and indexing techniques.
i) Directory method ii) Hash-based method
7. a) Describe the properties of MANETs.
b) Explain the dynamic source routing algorithm in MANETs.
8. a) Explain the functions of radio and baseband sublayers in Bluetooth.

MC November, 2011 Set3

IV B.Tech. I Semester Regular Examinations, November, 2011
MOBILE COMPUTING
(Common to Computer Science & Engineering, Information Technology and Electronics &
Computer Engineering)
Time: 3 Hours Max Marks: 80
Answer any FIVE Questions
All Questions carry equal marks
*******
1. a) Explain the architecture of mobile computing.
b) What are the functions or authentication and encryption in GSM? How is system
security maintained?
2. a) Who performs the MAC algorithm for SDMA? What could be possible roles of
mobile stations, base stations and planning from the network provider?
b) How are guard spaces realized between users in CDMA?
3. Explain how tunneling works in general and especially for mobile IP using IP-in-IP,
minimal and generic routing encapsulation respectively. Discuss the advantages and
disadvantages of these three methods.
4. a) Explain congestion control in traditional TCP.
b) Describe transaction oriented TCP. How does the integration of connection
establishment, data transfer, and close functions into one help in transmitting and
receiving at the TCP nodes.
5. a) Explain about context-aware computing.
b) Explain the situations in which a database can crash. How does a database recover
using recovery manager? What is the role of logged entries in updating transactions?
6. a) Describe pull-based data-delivery mechanism? What are the advantages and
disadvantages of pull-based data-delivery?
b) Explain the following selective tuning and indexing techniques.
(i) Flexible indexing method (ii) Distributed index based method
7. a) What are the benefits of location information for routing in ad-hoc networks, which
problems arise?
b) What are the security threats to a MANET? Why a MANET faces greater security
threats than a fixed infrastructure network?
8. a) Explain wireless session protocol.
b) Explain different user scenarios of Bluetooth.

MC November, 2011 Set2

IV B.Tech. I Semester Regular Examinations, November, 2011
MOBILE COMPUTING
(Common to Computer Science & Engineering, Information Technology and Electronics &
Computer Engineering)
Time: 3 Hours Max Marks: 80
Answer any FIVE Questions
All Questions carry equal marks
*******
1. a) What are the limitations of mobile and wireless devices?
b) How is localization, location update, roaming etc., done in GSM and reflected in
the databases? What are typical roaming scenarios?
2. a) Explain the term interference in the space, time, frequency and code domain.
What are counter measures in SDMA, TDMA, FDMA and CDMA systems.
b) Which of the MAC schemes can give hard guarantees related to bandwidth and
access delay?
3. a) What could be quick ‘solutions’ and why don’t they work?
b) List the entities of mobile IP and describe data transfer from a mobile node to a
fixed node and vice-versa. Why and where is encapsulation needed?
4. a) Explain snooping TCP.
b) Describe slow start of congestion control. How can fast recovery take place in
the congestion avoidance phase?
5. a) Explain client-server computing with adaptation.
b) Why does a mobile device take QoS issues into account while computing?
List the object models for application adaptation for the QoS constraints.
6. a) Explain the reasons for communication asymmetry in mobile network. Give
examples of asymmetric communication architecture for data dissemination.
b) Explain index-based method of selective tuning and indexing techniques.
7. a) How does the symmetry of wireless links influence the routing algorithms proposed.
b) What are the differences between AODV and the standard distance vector algorithm?
Why are extensions needed?
8. a) Explain the MAC layer of Bluetooth.
b) Describe the wireless application environment (WAE) logical model.

MC November, 2011 Set1

IV B.Tech. I Semester Regular Examinations, November, 2011
MOBILE COMPUTING
(Common to Computer Science & Engineering, Information Technology and Electronics &
Computer Engineering)
Time: 3 Hours Max Marks: 80
Answer any FIVE Questions
All Questions carry equal marks
*******
1. a) Explain the applications of Mobile Communications.
b) How is synchronization achieved in GSM? Who is responsible for synchronization
and why is it so important?
2. a) How are guard spaces realized between users in CDMA?
b) Define the problem of hidden and exposed terminals. What happens in the case of
such terminals if aloha, slotted aloha, reservation Aloha, or MACA is used?
3. a) What are general problems of mobile IP regarding security and support of QoS?
b) How can DHCP be used for mobility and support of Mobile IP?
4. a) Explain indirect – TCP.
b) Why is timeout freezing required in case of mobile nodes? What are the modifications
made in data link and TCP layers to enforce time-out freezing?
5. a) What are the advantages of hoarding data at the mobile device?
b) Explain query-processing architecture for processing a query using distributed
databases.
6. a) Explain hybrid data-delivery mechanism.
b) Explain other alternative methods of selective tuning and indexing techniques.
7. a) Why is routing in multi-hop ad-hoc networks complicated, what are the special
challenges?
b) How does dynamic source routing handle routing? What is the motivation behind
dynamic source routing compared to other routing algorithms from fixed networks.
8. a) Explain the functions of link manager in Bluetooth.
b) Describe J2ME features.

MC November 2009 Set4

IV B.Tech I Semester Regular Examinations, November 2009
MOBILE COMPUTING
(Common to Computer Science &Engineering, Information Technology,
Electronics &Computer Engineering)
Time: 3 hours Max Marks: 80
Answers any Five Questions
All Questions carry equal marks
*****
1. (a) Explain the protocol of GSM. [8]
(b) Explain in detail about GSM services. [8]
2. (a) Explain how multiple Access with collision Avoidance(MACA) can avoid hidden
terminals and exposed terminals problems. [8]
(b) Explain TDMA and its features. [8]
3. (a) What is the purpose of DHCP? Explain client initialization via DHCP. [8]
(b) Discuss about agent advertisement and delivery. [8]
4. (a) Explain the concept of Fast Retransmit/Fast Recovery in traditional TCP. [8]
(b) Explain snooping TCP. What are its advantages and disadvantages? [8]
5. (a) Explain in detail about context aware computing. [10]
(b) Explain the issues relating to Quality off service in mobile networks. [6]
6. (a) Explain communication asymmetry with the help of diagrams. [8]
(b) Explain interleaved push-pull based data delivery mechanism. [8]
7. (a) Write detailed notes on mobile Ad-hoc networks? [8]
(b) Explain Destination sequence distance vector routing algorithm in MANETs. [8]
8. (a) Explain different user scenarios of Bluetooth. [6]
(b) Explain wireless session protocol (WSP) of the session layer [10]

MC November 2009 Set3

V B.Tech I Semester Regular Examinations, November 2009
MOBILE COMPUTING
(Common to Computer Science &Engineering, Information Technology,
Electronics &Computer Engineering)
Time: 3 hours Max Marks: 80
Answers any Five Questions
All Questions carry equal marks
*****
1. (a) Explain the architecture of mobile computing. [8]
(b) Explain the following. [8]
(i) Handover in GSM (ii) Security services in GSM.
2. (a) What is CDMA? Explain in detail. [8]
(b) Explain the following problems of wireless transmission.
(i) Exposed Terminal (ii) Hidden Terminal (iii) Near and far Terminal [8]
3. (a) What is IP packet delivery? Explain it. [8]
(b) What is the main purpose of registration of a mobile node? Explain in detail. [8]
4. (a) Write the differences between TCP and UDP. [6]
(b) Explain Indirect-TCP. What are its advantages and disadvantages? [10]
5. (a) Explain the following cache invalidation mechanisms. [8]
(i) Stateful Asynchronous (ii) Stateless synchronous
(b) List and explain the context types in context-aware computing. [8]
6. (a) Explain push based data delivery mechanisms in detail. [8]
(b) Explain the following selective tuning techniques: [8]
(i) Directory method. (ii) Hash based method.
7. (a) Explain routing complications in mobile Ad-hoc networks. [8]
(b) Describe the working of mobile Ad-hoc networks. [8]
8. (a) Explain the MAC layer of Bluetooth. [8]
(b) Explain about the wireless application environment. [8]

MC November 2009 Set2

IV B.Tech I Semester Regular Examinations, November 2009
MOBILE COMPUTING
(Common to Computer Science &Engineering, Information Technology,
Electronics &Computer Engineering)
Time: 3 hours Max Marks: 80
Answers any Five Questions
All Questions carry equal marks
*****
1. (a) Explain the applications and limitations of mobile computing. [8]
(b) Explain GSM system architecture. [6]
2. Compare the following four medium access systems. [16]
(i) SDMA (ii) TDMA (iii) FDMA (iv) CDMA
3. (a) Explain the entities of mobile IP. [8]
(b) Describe Data transfer from a mobile node to a fixed node and vice versa. [8]
4. (a) Write detailed notes on Fast retransmit/fast recovery of Mobile transport
layer. [8]
(b) Explain Transmission/ Time-out freezing approach. [8]
5. (a) Explain power-aware computing. [8]
(b) Explain the following cache invalidation mechanisms. [8]
(i) State less Asynchronous (ii) Stateful synchronous
6. Explain data delivery methods in detail. [16]
7. (a) Explain in detail, properties of MANET. [8]
(b) Describe security problems in MANETs. [8]
8. (a) Explain the architecture of WAP. [10]
(b) Explain briefly about the wireless Datagram protocol (WDP) of transport layer.
[6]