cs9059 mobile computing

8/12/2019 Cs9059 Mobile Computing

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CS9059 MOBILE COMPUTINGUNIT I

Wireless Transmission Signal Propagation Sprea Spe!tr"m Satellite

Net#or$s Capa!it% &llo!ation '&M& (&M& M&C)

1. What are the 3 fundamental propagation behaviors depending on their

frequency?

Ground Wave

Sky Wave

Line of Sight

2.What is multipath propagation?

Multipath propagation is the direct from a sender to a receiver, the propagationeffects mentioned in the previous section lead to one of the most severe radio channel

impairments.

3. What is guard space?

Guard spaces are needed to avoid frequency band overlapping is also called

channel interference.

4. What are the 3 different basic shemes analog modulation?

Amplitude modulation

requency modulation

!hase modulation

5. What is the use of Phase oc! oop "P#?

"o receive the signal correctly, the receiver must synchroni#e in frequency and

phase $ith the transmitter.

$. What is hopping sequence?

"ransmitter and receiver stay on one of these channels %M and "%M. "he

pattern of channel usage is called the hopping sequence,

%. What is d&ell time?


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"he time spend on a channel $ith a certain frequency is called the d$ell time

'. What are the advantages of cellular systems?

"he advantages of cellular systems are,

i& 'igher capacity ii& Less transmission po$er iii& Local interface only iv&(obustness

(. What is bro&sing channel allocation and fi)ed channel allocation?

)ells $ith more traffic are dynamically allotted more frequencies. "his scheme iskno$n as bro$sing channel allocation, $hile the first fi*ed scheme is called fi*ed

channel allocation.

1*. What are the disadvantages of cellular systems?

"he advantages of cellular systems are,

+nfrastructure needed

'andover needed

requency planning

11. What is digital sense multiple access?

"he scheme $hich is used for the packet data transmission service. )ellular %igital

!acket %ata in the AM!S mobile phone system is also kno$n as digital sense multiple

access %SMA&.

12. What is +et&or! and ,&itching subsystem?

"he heart of the GSM is formed by the -et$ork and S$itching System -SS&. -SS

consists of the follo$ing s$itches and databases

Mobile Services s$itching centerMS)&

'ome Location register 'L(&

/isitor Location (egister /L(&

13. What is authentication centre?

As the radio interface and mobile stations are particularly vulnerable. A separate Au)has been defined to protect user identity and data transmission. "he Au) contains the

algorithms for authentication as $ell as the keys for encryption and generates the values

needed for user authentication in the 'L(.


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14. What is called burst and normal burst?

%ata is transmitted in small portions called bursts, normal burst are used for data

transmission inside a slot user and signaling data&.

15. What are the basic groups of logical channels?

GSM specifies 0 basic groups of logical channels,

"raffic channels

)ontrol channels

1$. -efine traffic multiframe and control multiframe?

"he periodic pattern of 01 slots occurs in all "%MA frames $ith a ")'.

"he combination of these frames is called traffic multiframe

"%MA frames containing data for the other logical channels are combined

to a control multiframe.

1%. What is /,02

3sing orthogonal codes separates the different data streams of a sender

3M"S uses so4called 5rthogonal /ariable Spreading factor codes 5/S&.

*+) Spe!i,% t-e steps per,orm "ring t-e sear!- ,or a !ell a,ter po#er on.

!rimary synchroni#ation

Secondary synchroni#ation

+dentification of the scrambling code

*9) E/plain ao"t transparent moe.

"he transparent mode transfer simply for$ards MA) data $ithout any furtherprocessing. "he system then has to rely on the 6) $hich is al$ays used in the radio

layer.

10) W-at are t-e asi! !lasses o, -ano2ers.

3M"S has 0 basic classes of handovers,

'ard handover


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Soft handover

6,7+,8

7.6)plain ,9 architecture?

Mobile services

o 8earer services

o "ele services

o Supplementary services

System architecture

(adio subsystem

-et$ork and s$itching subsystem

5peration subsystem

2. 6)plain ,ystem architecture?

!rotocol architecture

o !hysical Layer

o Medium access control Layer

o %ata link control layer

9.6)plain briefly about 767:;?

"he 0 standards are,

/oice %ata !acket data optimi#ed !%5&

"he system architecture of "6"(A is similar to GSM. "6"(A offers 0

channels similar to GSM as,

"raffic channels

control channels

4.Write brief about 97, and 97


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3ser equipment

)ore net$ork

'and over

UNIT31

TELECOMMUNIC&TION NETWO4S

Part3&

1. ,pecify the security services offered by ,9.

"here are three security services offered by GSM."hey are

8earer Services.

"ele Services.

Supplementary Services.

2. What is the frequency range of uplin! and do&nlin! in ,9 net&or!?

"he frequency range of uplink in GSM net$ork is :;


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+nternational mobile subscriber identity +MS+&.

"emporary mobile subscriber identity "MS+&.

Mobile station roaming number MS(-&.

$. What are the four possible handover scenarios in ,9?

"he four possible handover scenarios in GSM are

+ntra4cell handover.

+nter4cell, intra48S) handover.

+nter48S), intra4MS) handover.

+nter MS) handover.

%. What are the security services offered by ,9?

"he security services offered by GSM are

Access control and authentication.

)onfidentiality.

Anonymity.

'. What is meant by ,+?

GGS- is Gate$ay G!(S Support -ode. +t is the inter4$orking unit bet$een the

G!(S net$ork and e*ternal packet data net$orks. "he GGS- is connected to e*ternal

net$orks via the Gi interface and transfers packets to the SGS- via an +!4based G!(Sbackbone net$ork.

(. What is meant by ,,+?

SGS- is Serving G!(S Support -ode. +t supports the MS via the Gb interface."he SGS- is connected to a 8S) via frame relay.

1*. What is meant by ,,P?

8SSG! is 8ase Station Subsystem G!(S !rotocol. +t is used to convey routingand >oS4related information bet$een the 8SS and SGS-.8SSG! does not perform errorcorrection and $orks on top of a frame relay net$ork.

11. -efine the protocol architecture of -6=7.

"he protocol architecture of %6)" consists of three layers. "hey are


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!hysical Layer.

Medium Access Layer.

%ata Link )ontrol Layer.

-et$ork Layer.

"he first three layers are common for both )ontrol !lane )4!lane& and 3ser !lane34!lane&. "he net$ork layer has been specified only for 34!lane, so

that user data from layer t$o is directly for$arded to the 34!lane.

12. ,pecify the standards offered by 767:;.

"6"(A offers t$o standards. "hey are

/oice?%ata /?%&.

!acket %ata 5ptimi#ed !%5&.

13. >o& many 7 standardied groups of 3 radio access technologies

are there in 97


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1$. What are the t&o basic transport mechanisms used by -;?

"he t$o basic transport mechanisms used by %A8 are

Main Service )hannel MS)&.

ast +nformation )hannel +)&.

1%. What are the t&o transport modes defined for 9,=?

"he t$o transport modes defined for MS) are

Stream Mode

!acket Mode.

1'. -efine the terms8

i. 6arth ,tation.

ii. plin!.iii. -o&nlin!.

6arth ,tation8uality of service

!roprietary solutions.

(estrictions

Safety and Security

3.9ention the design goals of W;+,?

Global operation

Lo$ po$er

License4free operation

(obust transmission technology

Simplified spontaneous cooperation

6asy to use

!rotectiopn of investment

Safety and security

"ransparency for applications.

4.What is the difference bet&een infrastructure and ad


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point,but not directly bet$een the $ireless nodes.

Ad4hoc $ireless net$orks

)ommunication takes place directly $ith other nodes,so no access point

controlling medium acces is necessary.=.Give the primary goal of +666:


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77.-efine random bac!off time?

+f the medium is busy,nodes have to $ait for the duration of %+S,entering a contention

phase after$ards.6ach node no$ chooses a random backoff time $ithin a contention

$indo$ and delays medium access for this random amount of

time.

70.What is 7raffic ndication 9ap?

"he "+M contains a list of stations for $hich unicast data frames are

buffered in the access point.

79.What is -elivery 7raffic ndication 9ap

"he access point maintains a %"+M interval for sending broadcastmulticast

frames."he %"+M interval is al$ays a multiple of the "+M interval.

14.What is ;d


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8aseband

Link manager protocol

Logical link control and adaptation protocol

Service discovery protocol

1(.What is the purpose of sniff state?

"he sniff state has the highest po$er consumption."he device listens to the

piconet at a reduced rate.

2*.What is the use of hold state?

"he device does not release its AMA but stops A)L transmission.A slave may still

e*change S)5 packets.

21.What is the purpose of par! state?

+n this stae the device has the lo$est duty cycle and the lo$est po$er

consumption."he device releases its AMA and receives a parked member address."he

device is still a member of the piconet,but gives room for another device to become

active.


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!art48

1. 6)plain the architecture of 666 '*2.11.

System Architecture

!rotocol Architecture

!hysical layer

MA) layer

2. 6)plain the 9;= layer in 666'*2.11

3sing )SMA)A

With ("S)"S e*tension

With polling

MA) frames

9.6)plain >P6:;+ 1 in detail

'+!6(LA- 7

!rioriti#ation phase

6limination phase

Bield phase

"ransmission phase

>5S

4. 6)plain W;79

Working group

Services

(eference model

'andover

Location management

Mobile >5S


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5. Writ e short notes on luetooth.

_ 3ser Scenarios

_ Architecture

_

(adio Layer_ 8aseband layer

_ Link manager protocol

_ Security

_ S%!

UNIT8

MOBILE NETWO4 L&7E4

1. What are the requirements of mobile P?

)ompatibility

"ransparency

Scalability and efficiency

Security

2. 9ention the different entities in a mobile P

.

Mobile -ode

)orrespondent -ode

'ome -et$ork

oreign -et$ork

oreign Agent

'ome Agent

)are45f address

o oreign agent )5A

o )o4located )5A

3. What do you mean by mobility binding?

"he Mobile -ode sends its registration request to the 'ome Agent. "he 'A no$sets up a mobility binding containing the mobile nodeCs home +! address and the current

)5A.

4. -efine a tunnel.


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A tunnel establishes a virtual pipe for data packets bet$een a tunnel entry

and a tunnel endpoint. !ackets entering a tunnel are for$arded inside the

tunnel and leave the tunnel unchanged.

5. What is encapsulation?

6ncapsulation is the mechanism of taking a packet consisting of packet header and data

putting it into the data part of a ne$ packet.

$. What is decapsulation?

"he reverse operation, taking a packet out of the data part of another packet, is

called decapsulation.

%. -efine an outer header.

"he 'A takes the original packet $ith the M- as destination, puts it into the datapart of a ne$ packet and sets the ne$ +! header in such a $ay that the packet is

routed to the )5A."he ne$ header is called the outer header.

'. -efine an inner header.

"here is an inner header $hich can be identical to the original header as this case for +!4

in4+! encapsulation, or the inner header can be computed duringencapsulation.

9) What is meant by generic routing encapsulation.

Generic routing encapsulation allo$s the encapsulation of packets of one protocol suiteinto the payload portion of a packet of another protocol suite.

1*. What is the use of net&or! address translation?

"he net$ork address translation is used by many companies to hide internal

resources and to use only some globally available addresses.

11. -efine triangular routing.

"he inefficient behavior of a non4optimi#ed mobile +! is called triangular routing.

"he triangle is made up of three segments, )- to 'A, 'A to )5ADM-, and M-

back to )-.


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70. What is meant by a binding cache?

5ne $ay to optimi#e the route is to inform the )- of the current location by

caching it in a binding cache $hich is a part of the local routing table for the )-.

13. -efine binding request.

Any node that $ants to kno$ the current location of an M- can send a binding

request to the 'A. "he 'A can check if the M- has allo$ed dissemination of its current

location. +f the 'A is allo$ed to reveal the location it sends back a binding update.

14. What is !no&n as inding update?

"his message sent by the 'A to )-s reveals the current location of the M-."he

message contains the fi*ed +! address of the M- and the )5A."he binding update can

request an ackno$ledgement.

7=.6)plain binding ac!no&ledgement.

+f requested, a node returns this ackno$ledgement receiving a binding updatemessage.

71.-efine binding &arning.

+f a node decapsulates a packet for a M-, but it is not the current A for this M-,this node sends a binding $arning. "he $arning contains M-Cs home address and a

target node address.

1%. 6)plain cellular P

.

)ellular +! provides local handovers $ithout rene$ed registration by installing asingle cellular +! gate$ay for each domain, $hich acts to the outside $orld as a

foreign agent.

1'. What are the advantages of cellular P?

Manageability


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)ellular +! is mostly self4configuring, and integration of the )+!GW into a

fire$all $ould facilitate administration of mobility4related functionality.

6fficiency

"ransparency and security

1(. What is !no&n as mobility anchor point?

'M+!v1 provides micro4mobility support by installing a mobility anchor point,

$hich is responsible for a certain domain and acts as a local 'A $ithin this

domain for visiting M-s.2*. 6)plain destination sequence distance vector routing..

%estination sequence distance vector routing is an enhancement to distance vector

routing for ad4hoc net$orks and is used as routing information protocol in $ired

net$orks.

21. What are the t&o things added to the distance vector algorithm?

Sequence -umbers

%amping

00.>o& the dynamic source routing does divide the tas! of routing into t&o separate

problems2

7. (oute discovery

0. (oute Maintenance

P;:7 @

AAAAAAA

1. What are the requirements of a mobile P?

)ompatibility

"ransparency

Scalability and 6fficiencySecurity

0. What are the entities in mobile P?

Mobile -ode

)orrespondent node


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'ome -et$ork

oreign -et$ork

oreign Agent

)are45f4Address

oreign Agent

)o4located )5A'ome Agent

3. 6)plain tunneling and encapsulation in mobile P.

+!4in4+! encapsulation

Minimal encapsulation

Generic (outing encapsulation

4. -escribe -ynamic host configuration protocol.

%escription $ith diagram

Advantages

%isadvantages

5. 6)plain routing in Pv$.

6*ample ad4hoc net$orkAsymmetric links

(edundant Links

+nterference


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(%nami! Topolog%

UNIT3:

Part3&

1. What is slo& start?

")!Cs reaction to a missing ackno$ledgement is necessary to get rid of congestionquickly. "he behavior ")! sho$s after the detection of congestion is

called slo$ start.

2. What is the use of congestion threshold?

"he e*ponential gro$th of the congestion $indo$ in the slo$ start mechanism is

dangerous as it doubles the congestion $indo$ at each step. So a congestion threshold isset at $hich the e*ponential gro$th stops.

3. What led to the development of ndirect 7=P?

")! performs poorly together $ith $ireless links

")! $ithin the fi*ed net$ork cannot be changed.

"his led to the development of +4")! $hich segments a ")! connection

into a fi*ed part and a $ireless part.

4. What is the goal of 9


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Security layer

"ransaction layer

Session layer

Application layer

1*. +ame some =9P messages.

%estination unreachable

!arameter problem

Message too big

(eassembly failure

6cho requestreply

11. What is W7P? What are its classes?

W"! stands for Wireless "ransaction !rotocol. +t has been designed to runon very thin clients such as mobile phones. +t has three classes.

)lass


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"e*t and +mages

3ser interaction

-avigation

)onte*t Management

1$. What are the advantages of W9 ,cript over W9?

WML Script offers several capabilities not supported by WML

/alidity check of user input

Access to device facilities

Local user interaction

6*tension to the device soft$are

1%. +ame the libraries specified by W9,cript. Lang

loat

String

3(L

WML 8ro$ser

%ialogs

1'. What are the classes of libraries?

)ommon net$ork services

-et$ork specific services

!ublic services

1(. +ame the operations performed by P;P.

!ush access !rotocol performs the follo$ing operations

!ush submission

(esult notification

!ush cancellation

Status query

)lient capabilities query

2*. What are the components of W;P2.*?


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_ WML Script

_ Wireless "elephony Application

_ +ntroduction to WA!0.

cs9059 mobile computing

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