Mumbai University Question Papers Mobile Computing June 2008

Mumbai University question papers

 VII Sem CSE Examination June 2008

Mobile Computing

N.S. (1) Attempt any five questions.

(2) Marks to the right indicate full marks.

(3). Make suitable assumptions wherever necessary and clearly justify them.


1. Differentiate between the following: (At least four points) (any five) :-

(a) Infrastructure and Adhoc networks

(b) IPv4. and IPv6

(c) FHSS and DSSS .

(d) IEEE 802.11 a and IEEE 802.11 b

(e) Infra red & radio transmission

(f) FDMA and TDMA

(g) Indirect TCP and. Snooping TCP

(h) CDMA and GSM.


2. (a) Discuss about components and. interface of WAP 1.x architecture.

(b) Draw the block diagram of FHSS transmitter and receiver.

Differentiate between slow frequency hopping and fast frequency hopping.

(c) Explain the entities in brief:

(i) Home agent

(ii) Mobile node

(iii) Foreign agent

(iv) Care-of address.


3. (a) What are the functions of auth~nticationand encryption in GSM ? How is system security maintained?

(b) Explain ‘Bluetooth protocol stack’ with neat diagram.


4. (a) What characteristics do the different orbits have? What are their pros and cons?

(b) Explain how tunneling works for mobile IP using IP-in-IP, Minimal, and generic routing encapsulation, respectively. Discuss advantages and disadvantages of these three methods.


5. (a) How can DHCP be used for mobility and support of mobile IP ? 5

(b) Explain cellular system in detail with various handover mechanisms. 10

(c) Explainhiddenand exposedterminalsproblem. HowMACAavoidsthese problems? 5


6. Write a short notes on : (any two)

(a) GSM architecture

(b) Routing protocols in Ad-hoc networks.

(c) Mobile and wireless devices.

(d) Power management in IEEE 802.11 infrastructure networks.


7. (a) What are the benefits of reservation scheme? How collisions are avoided during data transmission? Explain DAMA scheme.

 (b) Two senders, A and B, want to send data. COMA assigns the following unique and 9rthogonal key sequences: key Ak=010011 for sender A, key Bk= 110101 for sender B. Sender A wants to send the bit Ad = 1, sender B sends Bd = O.Let us ,assume that we code a binary 0 as -1, a binary 1 as + 1, Show calculations, how spreading be achieved? What can the receiver detect for sender A and B respectively?


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