Name of the College : Noorul Islam College of Engineering
University : Anna University
Degree : B.E
Department : Information Technology
Subject Code/Name : IT 1404 – Mobile Computing
Document Type : Question Bank
Website : niceindia.com
Download Model/Sample Question Paper :https://www.pdfquestion.in/uploads/niceindia.com/3043-IT1404__MOBILE_COMPUTING.pdf
NICE Mobile Computing Question Paper
Part A :
1.Define SAMA :
Spread Aloha Multiple Access is a combination of CDMA and TDMA. The CDMA better suits for connection oriented services only and not for connection less bursty data traffic because it requires to program both sender and receiver to access different users with different codes.
Related : Noorul Islam College of Engineering EC1391 Telecommunication Systems B.E Question Bank : www.pdfquestion.in/3039.html
2.Define CDMA :
Code Division Multiple Access systems use codes with certain characteristics to separate different users. To enable access to the shared medium without interference. The users use the same frequency and time to transmit data. The main problem is to find good codes and to separate this signal from noise.
The good code can be found the following 2 characteristic :
1.Orthogonal.
2.AutoCorrelation.
3..What are the several versions in CSMA? :
There are several versions in CSMA, they are as follows
a) non-persistent CSMA
b) p-persistent CSMA
c) 1-persistent CSMA
4.What is meant by non-persistent CSMA? :
In, non-persistent CSMA, stations sense the carrier and start sending immediately if the medium is idle., if the medium is busy, the station pauses a random amount of time before sensing the medium again and repeating this pattern.
5.What is meant by p-persistent CSMA? :
In p-persistent CSMA system nodes also sense the medium, but only transmit with a probability of p. With the station deferring to the next slot with the probability 1-p,
i.e. access is slotted in addition.
6. What is SDMA? :
Space Division Multiple Access (SDMA) is used for allocating separated spaces to users in wireless networks. The basis for the SDMA algorithm is formed by cells and sectorized antennas which constitute the infrastructure implementing space division multiplexing (SDM)
7. What is FDD? :
In FDMA, the base station and the mobile station establish a duplex channel. The two directions, mobile station to base station and vice versa are separated using different frequencies. This Scheme is called Frequency Division Duplex (FDD)
8.What are the 2 sub layers in DLC? :
Logical Link Control(LLC)
Media Access Control(MAC)
9) What is EY-NMPA? :
Elimination yield –Non Pre-emptive Multiple Access (EY-NMPA) is a scheme which uses several phases to sense the medium. access the medium and for contention resolution.. Priority schemes can also be included. This is actually used in HIPERLAN1 specification.
10) What do you mean by Polling? :
Polling is a strictly centralized scheme with one master and several slave stations. The master can collect the list of stations during the contention phase and can poll these slaves according to many schemes like round robin, random access, reservation scheme etc.
11) What are the four types of handover available in GSM? :
1.Intra cell Handover
2.Inter cell Intra BSC Handover
3.Inter BSC Intra MSC handover
4.Inter MSC Handover
12) What is TETRA? :
TETRA (Terrestrial Trunked Radio) systems use different radio carrier frequencies, but they assign a specific carrier frequencies for a short period of time according to demand. TETRA’s are highly reliable and extremely cheap.
13) what are the categories of Mobile services? :
** Bearer services
** Tele services
** Supplementary services
14)What are the services provided by supplementary services? :
** User identification
** Call redirection
** Call forwarding
** Closed user groups
** Multiparty Communication
15) What are types of Handover? :
Intra-cell handover
Inter-cell ,intra- BSC handover
Inter-BSC, intra-MSC handover
Inter MSC handover