SEMESTER-IIComputer Science and EngineeringCS9251-MOBILE COMPUTING

MODEL EXAMINATION

Part –A: (10*2=20)Marks1 What is spreading factor?2.What is polling?3.Distinguish between soft handover& hard Hand over.4.Define foot print with respect to satellite systems.5.State the 3 phases of the medium access of different competing nodes.6.what are the power saving mechanisms in bluetooth?7.What are the drawbacks of wired networks?8.Define Dynamic Source Routing.9.What is the difference between TCP & UDP.10. Mention any 2 salient features of WAP.

Part-B : (5*16=80)Marks11 (a) i Discuss in detail about the types of antennas with their radiation patterns.(12) ii Explain Diversity techniques.(4) OR11 (b) Explain space, Frequency, code & Time division Multiplexing in detail.(16)

12 (a) Describe Digital Audio Broadcasting.(16) OR

(b)Explain the functional architecture of a GSM system..(16)

13 (a) Describe architecture of BLUE TOOTH.(16) OR (b)Explain Channel control sub layer in HIPERLAN.(16)

14 (a) Explain optimization in Mobile IP in detail.(16) OR (b)Explain IPV6 Protocol in detail.(16)

15 (a) Discuss the role of WWW in support for mobility.(16) OR

(b) Explain the following: (i) Indirect TCP. (8 ) (ii)Snooping TCP.(8)

B.E./B.Tech. DEGREE EXAMINATION, NOVEMBER/DECEMBER 2009.Seventh SemesterInformation TechnologyIT1402- MOBILE COMPUTING(Regulation 2004)

Time: Three hours Maximum:100 marks

Answer ALL questions.PART A- (10 X 2= 20 Marks)

1. Why do Hidden and Exposed terminal problems arise?

2. Differentiate Broadcast from Multicast.

3. Detail the features of MSAT.

4. How can an efficient routing be made in satellite systes?

5. When are tuning frequency and frequency considered?

6. How can you utilize mobile antennas efficiently?

7. Compare various modulation techniques.

8. When it's required to go for GMSK, GFSK and DQPSK?

9. In what functionalities Switches differ from Routers?

10. How and why does I-TCP isolate problems on the wireless link?

PART B - (5 X 16 = 80 Marks)

11. (a) Consider three users and Barker code of six bits each for the users transmitting the signals, introduce noise and near/far problem while transmitting and reconstruct the data in the receiving side providing the proper countermeasures for the complications. (Note: Use CDMA technologies) (Marks 16)(Or)

(b) (i) Table the frequency bands useed for wireless applications with their ranges, propagation models and applications. (Marks 6)

(ii) Represent diagrammatically the protocol machines for multiple access with collision avoidance. (Marks 10)

12. (a) (i) Sketch the data network in your campus. How many hosts are there and how large is the user population? What is the speed of the access link to the Internet? How so you gain access to the Internet? How much does home access to the Internet costs? (Marks 10)

(ii) Why are so many different identifiers/addresses (e.g. MSISDN, TMSI, IMSI) needed in GSM? Give reasons and distinguish between user- related and system related identifiers. (Marks 6)(Or)

(b) (i) Consider a mobile user who is migrating from a place to another place, provide him a seamless service by satellite system, also sketch the architecture. (Marks 8)

(ii) Discuss the importance of DECT Protocol Layers. (Marks 8)

13. (a) (i) Detail the time- bounded service on top of the standard DCF mechanism where ad hoc networks cannot use the function. (Marks 8)

(ii) Discuss the PHY frame format of an IEEE 802.11 using the spread spectrum technique which separates by code. (Marks 8)(Or)

(b) (i) The channel access control sublayer of HIPERLAN offers a connectionless data transfer service to the higher MAC layer. Justify the above statement with related references. (Marks 10)

(ii) Discuss the functionalities and support provided by L2CAP. (Marks 6)

14. (a) Discuss and detail the differences in topology reorganization in DSDV and DSR routing protocols. (Marks 16)(Or)

(b) (i) What are the general problems of mobile IP regarding security and support of quality of service? (Marks 8)

(ii) Name the inefficiencies of mobile IP regarding data forwarding from a correspondent node to a mobile node. What are optimizations and what additional problems do they cause? (Marks 8)

15. (a) What are the major difference between WAP 2.0 and WAP 1.x? What influenced the WAP 2.0 development? (Marks 16)(Or)

(b) Detail about UTMS Radio Interfaces in Frequency Division Duplex and Time Division Duplex modes. (Marks 16)

MAY /JUNE 2009MOBILE COMPUTING.ElectivePart –A1. Define near /far effect?2. Give any two application of satellite systems?3. What are ad-hoc networks?4. Define handover in WATM?5. What is meant by Registration lifetime of a packet ?6. What is meant by tunneling?7. How does the standard TCP behave when a packet is lost during transmission?8. Define time – out freezing?9. Mention the role of transaction layer in WAP?10. Mention any two messages of WCMP?

Part –B

11. a)Explain in detail:i)DECT system. [Mark 8]ii)TETRA system. [Mark 8]Orb) i) Discuss LEO,MEO, and GEO satellite systems. [Mark 8] ii) Discuss Digital Video Broadcasting. [Mark 8]

12. a )Explain in detail:i)HIPERLAN [Mark 8]ii) BLUETOOTH [Mark 8] Orb) What is meant by WATM? Describe WATM reference model, location management , services and QOS. [Mark 16]13.a) i) Discuss the purpose and application of DHCP. [Mark 8] ii) Explain agent discovery and registration. [Mark 8]Orb) Explain the various routing strategies in mobile ad-hoc networks?14. a) Explain any 4 classical TCP improvement techniques. [Mark 16]Or

b) i)Discuss Transaction oriented TCP in detail. [Mark 8]ii) Discuss TCP over 2.5/3G wireless networks. [Mark 8] 15.a) Discuss the component of WAP arch/- and its application environment. [Mark 16]Orb)i)Write short notes on WML script. [Mark 8]ii) Discuss WTA? [Mark 8]

B.E. / B.Tech DEGREE EXAMINATION, NOVEMBER/DECEMBER 2008

Seventh Semester

Information Technology

IT1402 – MOBILE COMPUTING

(Regulation 2004)

Time: Three hours Maximum: 100 marks

Answer ALL questions.

PART A – (10 x 2=20 marks)

1. Differentiate analog modulation and digital modulation.2. How are guard spaces realized between users in CDMA?3. What are the general problems of satellite signals travelling from a satellite to receiver?4. Differentiate symmetrical and asymmetrical communication system.5. What is HIPERLAN?6. How is mobility restricted using WLANS?7. What could be quick ‘solutions’ and why don’t they work?8. What advantages does the use of IPV 6 offer for mobility?9. Write the advantages and disadvantages of mobile TCP.10. Define fast retransmit.

PART B – (5 x 16 = 80 marks)

11. (a) Explain in detail about multiplexing.

Or(b) Explain the following :(i) MAC(ii) SDMA.

12. (a) Explain the functional architecture of a GSM system.

Or(b) Discuss about digital video broadcasting.

13. (a) Explain the concept of blue tooth architecture.

Or

(b) Explain the concept of IEEE 802.11 medium access control layer.14. (a) Explain the following :(i) DSDV [Marks 8](ii) Ad-hoc DSR. [Marks 8]

Or(b) Discuss about tunneling and encapsulation mechanism and reverse tunneling.

15. (a) Explain and detail about traditional TCP.

Or(b) (i) Briefly explain about indirect and snooping TCP. [Marks 8](ii) Briefly discuss about WAP.[Marks 8]

B.E/B.Tech. Degree Examination, April/May 2008Eighth Semester(Regulation 2004)Computer Science and Engineering

IT 1402- Mobile Computing

Part-A(10*2=20 marks)

1. Assume a receiver is located 10 km from a 150 W transmitter. The carrierfrequency is 6 GHz and free space propagation is assumed, Gain at transmitter is 1 dB and Gain at receiver is 1 dB.

(a) Calculate the transmit power in dBW.

(b) Find the power at the receiver in Watts.

2. What limits the number of simultaneous users in a TDM/FDM system comparedto a CDM system ? What happens to the transmission quality of connectionsif the load gets higher on the cell ?

3. Consider the handoff procedure in GSM system that is based on relativesignal strength with threshold; that is, a mobile switches from one cellto another if (a) the signal at the current BS is sufficiently weak (lessthan a predefined threshold) and (b) the other signal is stronger thanthe two. What are the drawbacks of this scheme, when the threshold is too low or too high ?

4. State the different types of transport modes and channels used to carrypackets in Digital Audio Broadcasting.

5. In the Distributed Coordination Function(DCF) protocol of IEEE 802.11,

why does a Node wait only SIFS time units (after the last data packet reception) before sending an ACK, while waiting DIFS time units beforeattempting a data transmission ?

6. What are the advantages and problems of forwarding mechanisms in Bluetoothnetworks regarding security and power saving ?

7. How can DHCP be used for mobility and support of Mobile IP ?

8. What are the differences between AODV and the standard distance vector algorithm ? Why are extensions needed ?

9. How and why does I-TCP isolate problems on the wireless link ? What arethe main drawbacks of this solution ?

10.Mention two WAP service providers. Find two cell phones supporting WAPand identify which WAP version they support.

Part-B(5*16=80 marks)

11. (a) How does frequency reuse enhance cellular network capacity ? Besidesthe number of users, what other major factor influences the decisionon cluster size ? A cellular system uses frequency spectrum 1800 MHzto 1840 MHz for uplink channels and 1860 MHz to 1900 MHz for downlinkchannels respectively. Each channel takes 200 KHz and can be sharedby 8 users. Each user needs one uplink and one downlink channel. Howmany users can be supported without frequency reuse in this cellularsystem ? [16]

(OR)

(b) What is the use of spread spectrum ? Sketch the block diagram of theTransmitter and Receiver of DSSS. Explain what each block does and what the signal looks like (in time and/or frequency domains) at eachlocation in the block diagram with an example.[16]

12. (a) Name the main elements of GSM system architecture and describe their functions. What are the advantages of specifying not only the radiointerface but also the internal interfaces of the GSM system ? Explain the inter-BSC,intra-MSC handover process in the GSM systemusing typical signals and a message sequence chart. Explain the decision points and the resource allocation steps,if they exist.[16]

(OR)

(b) What is DAB ? Explain the components,frame format and the protocolused by DAB to access different formats of data also describe howDVB is used for data broadcasting and to access high speed internet.[16]

13. (a) (i) Using IEEE 802.11 (DCF): S1 and S2 send CBR/UDP traffic to the common destination D. Consider S1,S2 and D all within receiverange of each other when the basic scheme is used (no RTS/CTS):Describe a collision (what happens before,during and after).Whatdoes the collision probability depend on ? When RTS/CTS is used:What are the changes to the previous answers ? comment also on the throughput and fairness. [16]

(OR)

(b) (i) Describe the briefly how collision is avoided in HIPERLAN-1. [8]

(ii)Draw the protocol architecture of Bluetooth and explain brieflythe Base band layer and L2CAP of Bluetooth. [8]

14. (a) Given the network topology below, use the dynamic source routing algorithm to compute the shortest path from A to all other nodes.Make sure to show the results of the computation at each step.[16]

7B --- D|\ 1/ || \ / |12| /\ |1| /10\ |A --- C -------- E3 1

(OR)

(b) Consider a mobile node MN from network X. The user of MN wishes to communicate with a corresponding node CN in network Y. The node MNmoves from X to a foreign network A. Describe the sequence of messages that are required in Mobile IPv4 so that MN and CN cancontinue to communicate. Include both the user data messages and theMobile IP control messages. Now, consider the case where CN moves to foreign network B while MN is still in the foreign network A. CanCN and MN still communicate ? (Does Mobile IP support both endpoints

moving? ) Show the message flow to indicate how it will succeed or fail in this case. [16]

15. (a) As a transport layer protocol, TCP uses a window mechanism to exercise flow control over the best effort IP in the internet.Flow control is exercised by the edge router based on congestionstatus encountered in the core routers between teh TCP sender andTCP receiver.

(i) Describe the operation of the window flow control mechanism. [8]

(ii)ACKs from the TCP receiver are the basis that the TCP sender uses to adjust the sending window size. Describe and discusshow ACKs are used for this purpose. [8]

(OR)

(b) Specify the enhancements made to the basic client server architectureof the web to suit a mobile wireless user ? Briefly discuss the maingoals of WAP. Expain the layers of WAP protocol used to achieve thefollowing : A client wants to have a shared state with the serverfor transferring the content. [16]

DEGREE EXAMINATION

MOBILE COMPUTINGTime : Three Hours Maximum : 100 marksPART A (10 x 2 = 20 marks)

1. What is a guard space?2. What is CMDA?3. List the four possible handover and scenarios in GSM4. Define inclination angle and elevation angle5. Give the 802.11 PHY frame format using DSS6. What are the low power states of a blue tooth device?7. What is a care of address?8. What are the routing metrics in wireless adhoc network?9. What is a wireless Telephony application?10. List the classes of transaction service of WTP.

PART B (5 x 16 = 80 marks)

11. (a) Discuss in detail the Wireless Transaction Protocol. (16)(or)(b) Discuss in detail the Wireless Session Protocol (16)

12. (a) Explain time division multiple access (16)

(or)(b) (i) Discuss the spread spectrum techniques (10)(ii) What is Code Division Multiplexing? Explain (6)

13. (a) (i) Discuss in detail localization, calling and handover in GSM (10)(ii) Explain the types of orbits in satellite system (6)(or)(b) (i) Explain the GSM system architecture (12)(ii)Explain the protocol architecture of DECT (4)

14. (a) Discuss in detail the medium access control mechanism of ICCC 802.11 (16)(or)(b) (i) Explain the information bases and networking of adhoc HIPERLAN. (8)(ii) Discuss MAC layer bluetooth system (8)

15. (a) (i)Describe tunneling and encapsulation in Mobile IP (8)(ii) Discuss in detail dynamic source routing (8)(or)(b) (i) Write short notes on reverse tunneling (4)(ii) Explain IP packet delivery, agent advertisement, discovery and registration process in

mobile IP (12)

DEGREE EXAMINATIONMOBILE COMPUTINGTime : Three Hours Maximum : 100 marks

PART A- (10x2=20 marks)1. What is spreading factor?2. What is polling?3. Distinguish between soft hand over and hard hand over.4. Define footprint with respect to satellite systems.5. State the three phases of the medium access of different competing nodes.6. What are the power saving mechanisms in Bluetooth?7. What are the drawbacks of wired networks?8. Define: Dynamic Source Routing.9. What is the difference between TCP and UDP?10. Mention any two salient features of WAP.

PART B- (5x16=80 marks)11.(a)(i) Discuss in detail the types of Antennas with their radiation patterns. (ii) Explain Diversity techniques.

OR (b) Explain Space, Frequency, Code and Time Division multiplexing in detail.

12.(a) Describe Digital Audio Broadcasting.OR

(b) Explain routing, localization and hand over in satellite systems.

13.(a) Describe the architecture of BLUE TOOTH.OR

(b) Explain channel control sub layer in HIPERLAN.

14.(a) Explain optimization in Mobile IP in detail.OR

(b) Explain IPv6 protocol in detail.

15.(a) Discuss the role of WWW in support for mobility.OR

(b) Explain the following:(i) Indirect TCP.

(ii) Snooping TCP.(iii) Explain about performance enhancing proxies.