Noise & Its Effects on Mobile Understanding GSM & CDMA Basics of GSM Architecture And services like voice call , SMS ,MMS ,LBS,VAS Different Modes used for Mobile Communication Architecture of Mobile Computing(3 Tier)

1. Mobile Technologies
Introduction to Mobile
Computing
Ms. Swapnali Pawar
Swapnali Pawar
1

2. 1. Noise & Its Effects on Mobile
2. Understanding GSM & CDMA
3. Basics of GSM Architecture
And services like voice call , SMS ,MMS ,LBS,VAS
4. Different Modes used for Mobile
Communication
5. Architecture of Mobile Computing(3Tier)
1.3 Introduction to Mobile Computing
Swapnali Pawar
2

3. Noise & Its Effects on Mobile
What is Noise?
Noise is an unwanted signal which interferes with the original message
signal and corrupts the parameters of the message signal.This alteration in the
communication process, leads to the message getting altered. It is most likely to
be entered at the channel or the receiver.The noise signal can be understood by
taking a look at the following example.
Swapnali Pawar
3

4. Hence, it is understood that noise is some signal which has no pattern
and no constant frequency or amplitude. It is quite random and
unpredictable. Measures are usually taken to reduce it, though it can’t be
completely eliminated.
Most common examples of noise are −
Hiss sound in radio receivers
Buzz sound amidst of telephone conversations
Flicker in television receivers, etc.
Swapnali Pawar
4

5. Definitions of Noise:
• Noise is unwanted signal that affects wanted signal.
• Noise can broadly be defined as any unknown signal that
affects the recovery of the desired signal.
• Noise is an unwanted signal, which interferes with the
original message signal and corrupts the parameters of the
message signal.This alteration in the communication process,
leads to the message getting altered. It most likely enters at the
channel or the receiver. N
Swapnali Pawar
5

6. Noise Affects Mobile Communication
Swapnali Pawar
6

7. Faulty house wiring, long cables or the phone line itself could be indirectly
disrupting your conversations. Other culprits include the following:
Weather: Precipitation can leak into phone lines and cause
disruptions. Lightning, even at a distance, can damage the connection.
Electrical interference: Power lines, radio or television transmitters,
transformers and other electronic devices may cause noise on the phone
line.
Other phone devices: Fax or answering machines, other phones
and line splitters -- devices that allow two phones to fit on one phone
jack -- can cause phone line noise.
DSLservices:The high-frequency signals coming from DSL (digital
subscriber line) devices sharing the phone line can create problems for
other technology connected to the line.
A good rule of thumb is that if the noise only happens occasionally, then
weather is to blame. If it's a constant annoyance, then it's probably another
offender.
Swapnali Pawar
7

8. Effects of Noise
Noise is an inconvenient feature which affects the system performance.
Following are the effects of noise.
Noise limits the operating range of the systems
Noise indirectly places a limit on the weakest signal that can be amplified
by an amplifier.The oscillator in the mixer circuit may limit its frequency
because of noise.A system’s operation depends on the operation of its
circuits. Noise limits the smallest signal that a receiver is capable of
processing.
Noise affects the sensitivity of receivers
Sensitivity is the minimum amount of input signal necessary to obtain the
specified quality output. Noise affects the sensitivity of a receiver system,
which eventually affects the output.
Swapnali Pawar
8

9. • Most common examples of noise are:
• Hiss sound in radio receivers
• Buzz sound amidst of telephone conversations
• Flicker in television receivers,
• Effect of noise
• Degrades system performance(Analog and digital)
• Receiver cannot distinguish signal from noise
• Efficiency of communication system reduces
Swapnali Pawar
9

10. Types of Noise
The classification of noise is done depending on the
type of the source, the effect it shows or the relation
it has with the receiver, etc.
There are two main ways in which noise is
produced.
1.External source
2.Internal source
Swapnali Pawar
10

11. 1.External Source
This noise is produced by the external sources which may
occur in the medium or channel of communication, usually.This
noise cannot be completely eliminated.The best way is to
avoid the noise from affecting the signal.
Examples
Most common examples of this type of noise are −
Atmospheric noise (due to irregularities in the atmosphere).
Extra-terrestrial noise, such as solar noise and cosmic noise.
Industrial noise.
Swapnali Pawar
11

12. 2.Internal Source
This noise is produced by the receiver components while
functioning.The components in the circuits, due to continuous
functioning, may produce few types of noise.This noise is
quantifiable.A proper receiver design may lower the
effect of this internal noise.
Examples
Thermal agitation noise (Johnson noise or Electrical noise).
Shot noise (due to the random movement of electrons and holes).
Transit-time noise (during transition).
Miscellaneous noise is another type of noise which includes
flicker, resistance effect and mixer generated noise, etc.
Swapnali Pawar
12

13. Noise Sources
Swapnali Pawar
13

14. 1.External Noise :
• It is due to Man- made and natural resources
• Sources over which we have no control such as thunders,
snow fall, lightning etc.
• Examples are Motors, generators, atmospheric sources.
2.Internal Noise:
• It is due to random movement of electrons in electronic
circuits
• Major sources are resistors, diodes, transistors etc.
•Thermal noise or Johnson noise and shot noise are examples.
Swapnali Pawar
14

15. Atmospheric Noise Or Static Noise:
• Caused by lighting discharges in thunderstorms
•The electrical impulses are random in nature and spread over most of the RF
spectrum used in broadcasting
•Atmospheric Noise consists of false radio signals and distributed over wide
range of frequencies
•Atmospheric noise is less severe about above 30 MHz
Industrial Noise:
The noise is effective in industrial and densely populated area
•Automobile and aircraft ignition • Leakage from high voltage line
• Heavy electric machine
• Fluorescent light etc.
•The noises are observable at frequencies in range of 1MHz to 600 MHz
Swapnali Pawar
15

16. Extraterrestrial Noise or Space Noise:
Caused by radiation of RF noise by sun and distant stars
• Solar Noise: Sun is large body at a very high temperature over
6000 0C on the surface and radiates over a very broad frequency
spectrum which includes the frequencies we use for
communication.
• Cosmic Noise: Distant stars are also suns and have high
temperatures, the radiate RF noise in the same manner as our sun.
•The noise received is called thermal (or black body) noise and is
distributed uniformly over the entire sky.
•This noise is observable at frequencies in the range of 8MHz to
1.43 GHz
Swapnali Pawar
16

17. Signal to Noise Ratio
Signal-to-Noise Ratio (SNR) is the ratio of the
signal power to the noise power.The higher the
value of SNR, the greater will be the quality of the
received output.
Figure of Merit
The ratio of output SNR to the input
SNR can be termed as the Figure of merit (F).
It is denoted by F. It describes the performance
of a device
Quality Measure
Swapnali Pawar
17

18. Noise ReductionTechnology for Cell Phones
Plenty of people are interested in reducing noise interference on
cell phones, too. Newer models come with echo cancellation and
other noise-reduction technologies built in.
Makers of wireless headsets, such as Plantronics, aggressively
market their device's ability to remove the background
noise from your very important conversation with digital signal
processing technology.
Swapnali Pawar
18

19. UNDERSTANDING GSM & CDMA
• Cellular mobile services have been used all over the world for a long
time and still evolving day by day.
With these services, various communication services also evolved,
and CDMA and GSM are two of them.
• CDMA and GSM are the two most important technology standards
that are known for mobile communication.
• Both the GSM and CDMA converts the data from the mobile phone
into radio waves.
• But these technologies are differentiated in the way in which the
calls & data transfer takes place over a network.
• One of the key differences between CDMA and GSM is that GSM
uses SIM cards to connect a mobile phone with its network,
whereas CDMA does not need any SIM card and operates on ESNs
(Electronic Serial Number).
Swapnali Pawar
19

20. What is GSM?
• GSM or Global System for Mobile Communication is a digital mobile
communication standard, which is used for transmitting and receiving data and voice signals
over a network.
• It is also known as the second-generation standard for mobile networks or
telecommunication, and it operates on a wedge spectrum.
• GSM uses the TDMA (Time Division Multiple Access) and FDMA (Frequency Division
Multiple Access) for separating the users & cells and transmitting the signals.
• Due to the GSM standard, various other wireless services such as GPRS(General Packet
Radio Service), UMTS(Universal Mobile Radio System), and EDGE(Enhanced
Data Rates for GSM Evolution) have also evolved.
• It operates on three different radio frequencies, which are 900MHz, 1800MHz, and
1900MHz.
• Among these three frequencies, the 900MHz band frequency is used by the Original GSM
system, and the 1800 MHz band frequency is used to provide the added support for
increasing customers.The 1900MHz band is specifically used in the US (United States).
• The GSM users have first taken advantage of the service Short Message System (SMS),
by which the users can communicate with each other using text messages over the given
network.
Swapnali Pawar
20

21. Swapnali Pawar
21
What is GSM?

22. Advantages of GSM
• With GSM technology, we can have a low-cost mobile set and
base stations.
• It improves spectrum efficiency.
• The data or voice signals are of high quality in GSM.
• The GSM is compatible with ISDN (Integrated Services Digital
Network)
Swapnali Pawar
22

23. What is CDMA?
• CDMA is an acronym for Code Division Multiple
Access, which is also a radio telecommunication standard
similar to GSM.
Swapnali Pawar
23

24. • The CDMA came into existence in 2G and 3G generation as
the protocol of wireless communication.
• It is based on the spread spectrum technology and makes
optimal use of the available bandwidth. Since it uses the spread
spectrum technology, hence allows each user to transmit the
data over the entire frequency spectrum at any time.
• The CDMA provides one of the most secure modes of
communication due to its spread spectrum property.
• It is used in UHF or Ultra high-frequency cellular
systems, with frequency bands ranging from 800MHz to
1900MHz.
What is CDMA?
Swapnali Pawar
24

25. Swapnali Pawar
25
CDMA Network Architecture
Interfaces to other
networks

26. Advantages of CDMA
• It uses a fixed frequency spectrum in an efficient way.
• There is no limit on the number of Users.
• It provides a flexible allocation of resources.
• It is compatible with other cellular technologies; hence it
allows nation-wide roaming.
Swapnali Pawar
26

27. • GSM stands for Global System for Mobile communication,
while CDMA stands for Code Division Multiple Access GSM uses FDMA
(Frequency division multiple access) and TDMA (Time division multiple access).
• GSM supports transmitting data and voice both at once, but CDMA have not
this feature.
• The main distinction between GSM and CDMA is that in GSM, the customer
information is put on a SIM card which can be moved to a new mobile phone.
Whereas only mobile phones from a set of whitelisted companies can be used
with a CDMA network
Comparison between CDMA and GSM
Swapnali Pawar
27

28. CDMA GSM
It stands for Code Division Multiple
Access.
It stands for Global System for Mobile
Communication.
It uses a CDMA mechanism for data & call
transmission.
It uses TDMA and FDMA mechanism
for data & voice transmission.
The transmission rate is fast compared to
GSM.
The transmission rate is slow compared
to CDMA.
It uses EVDO data transfer technology. It uses EDGE data transfer technology.
It is handset specific and does not require
any SIM for communication.
It is SIM specific, hence requires a SIM
card for communication.
During transmission, it is much prone to
radiation emission.
During transmission, it is comparatively
less prone to radiation emission.
It offers more secure communication
compared to GSM.
It offers less secure communication
compared to CDAM.
The signal detection is difficult in CDMA. The signal detection is easy in GSM.
It provides built-in encryption. It requires additional encryption as no
built-in encryption is available.
It enables limited roaming. It enables worldwide roaming.
Comparison Chart between CDMA and GSM
Swapnali Pawar
28

29. Serial No. GSM CDMA
1. Full form Global System for Mobile
communication.
Code Division Multiple Access.
2.Technology used FDMA(Frequency division
multiple access) andTDMA
(Time division multiple access).
CDMA(Code division multiple
access).
3.Availability GSM is globally widely used and
available.
CDMA is available in fewer
countries and carriers.
4. Data speed rate 42Mbps in HSPA (3G). 3.6Mbps in CDMA.
5.Features GSM supports transmitting data
and voice both at once.
CDMA does not support this
feature.
6. Customer
Information
Stored in a SIM card. Stored in a headset or phone.
Comparison Chart between CDMA and GSM
Swapnali Pawar
29

30. How to check if the phone is based on GSM or CDMA technology?
To check if your mobile phone is GSM-based or CDMA based, check the
below points:
1. Check from your Phone Settings:
For iPhone users: Go to Settings→General→About→ check for
the MEID,ESN,or IMEI number near the bottom of the menu.
For Android users: Go to Settings→ System→About Phone→Click
to Status, and check for the MEID,ESN,or IMEI number.
In both cases, if you see the MEID or ESN number, then your phone is
CDMA based. If you see the IMEI number, then your phone is a
GSM-based phone. If you see both options, it means your device supports
both technologies.
2. Check for SIM card Slot on the Phone:
As discussed above, the GSM phone makes use of SIM cards, whereas CDMA
not. So, you can check on your mobile phone whether it contains a SIM slot
or not. But due to widely spread of 4G LTE technology, most CDMA devices
also use SIM cards, so this way of checking is less helpful now.
Swapnali Pawar
30

31. Basics of GSM Architecture
Swapnali Pawar
31

32. GSM Architecture:
The GSM architecture consists of three major interconnected
subsystems that interact with themselves and with users through
certain network interface.The subsystems are
• Base Station Subsystem (BSS)
• Network Switching Subsystem (NSS)
• Operational Support Subsystem (OSS)
Mobile Station (MS) is also a subsystem but it is considered as a
part of BSS
Swapnali Pawar
32

33. GSM Architecture
Swapnali Pawar
33

34. 1. Mobile Station (MS): Mobile Station is made up of two entities.
A. Mobile equipment (ME):
It is a portable, vehicle mounted, hand held device.
It is uniquely identified by an IMEI number.
It is used for voice and data transmission. It also monitors power and signal
quality of surrounding cells foe optimum handover. 160 characters long SMS
can also be sent using Mobile Equipment.
B. Subscriber Identity module (SIM):
It is a smart card that contains the International Mobile Subscriber Identity
(IMSI) number.
It allows users to send and receive calls and receive other subscriber services.
- It is protected by password or PIN.
It contains encoded network identification details. it has key information to
activate the phone.
It can be moved from one mobile to another.
Swapnali Pawar
34

35. 2. Base Station Subsystem (BSS): It is also known as radio
subsystem, provides and manages radio transmission paths between the
mobile station and the Mobile Switching Centre (MSC). BSS also manages
interface between the mobile station and all other subsystems of GSM. It
consists of two parts.
A. BaseTransceiver Station (BTS):
It encodes, encrypts, multiplexes, modulates and feeds the RF signal to the
antenna.
It consists of transceiver units.
It communicates with mobile stations via radio air interface and also
communicates with BSC viaAbis interface.
B. Base Station Controller (BSC):
It manages radio resources for BTS. It assigns frequency and time slots for all
mobile stations in its area.
It handles call set up, transcoding and adaptation functionality handover for
each MS radio power control.
It communicates with MSC viaA interface and also with BTS.
Swapnali Pawar
35

36. 3. Network Switching Subsystem (NSS):
it manages the switching functions of the system and allows MSCs to communicate with other networks
such as PSTN and ISDN. It consist of
A. Mobile switching Centre:
It is a heart of the network. It manages communication between GSM and other networks.
It manages call set up function, routing and basic switching.
It performs mobility management including registration, location updating and inter BSS and inter MSC call
handoff.
It provides billing information.
MSC does gateway function while its customers roam to other network by using HLR/VLR.
B. Home Location Registers (HLR): - It is a permanent database about mobile subscriber in a
large service area. - Its database contains IMSI, IMSISDN, prepaid/post-paid, roaming restrictions,
supplementary services. Subscriber profile, location info, status.Subscription info of registered user stored
C.Visitor Location Registers (VLR): - It is a temporary database which updates whenever new MS
enters its area by HLR database. - It controls mobiles roaming in its area. It reduces number of queries to
HLR. - Its database contains IMSI,TMSI, IMSISDN, MSRN, location, area authentication key.
D.Authentication Centre(AUC) : - It provides protection against intruders in air interface. - It
maintains authentication keys and algorithms and provides security triplets (RAND, SRES, Ki). Protected
database.Stores a copy of secret key.Used for authentication.Protects from different type of fraud.
E. Equipment Identity Registry (EIR):
It is a database that is used to track handset using the IMEI number. Db that contain list of all valid mobile on
network.IMEI used to indentify each MS.It is made up of three sub classes- the white list, the black list and
the gray list.
Swapnali Pawar
36

37. 4. Operational Support Subsystem (OSS):
It supports the operation and maintenance of GSM and
allows system engineers to monitor, diagnose and
troubleshoot all aspects of GSM system.
It supports one or more Operation Maintenance
Centres (OMC) which are used to monitor the
performance of each MS, Bs, BSC and MSC within a GSM
system.
It has three main functions:
• To maintain all telecommunication hardware and
network operations with a particular market.
• To manage all charging and billing procedures
• To manage all mobile equipment in the system.
Swapnali Pawar
37

38. Operation Maintenance Center (OMC) –
This dept maintain all telecommunications hardware and network operations with a
particular market.
It also Manage all charging and billing procedures.
It also Manage all mobile equipment in the system.
Public Network
The public switched telephone network (PSTN)
Integrated Services Digital Network (ISDN)
Data Networks
The public switched telephone network (PSTN) –
The public switched telephone network (PSTN) is the worldwide collection on
interconnected public telephone network that was designed primarily for analog calls.
PSTN was only an analog system, but it is now almost entirely digital.
PSTN uses signaling system no. 7, SS7 as signal protocol.
SS7 is used to set up and terminate a telephone call.
Integrated Services Digital Network (ISDN) –
ISDN is a set of international communicate standards designed in 1980’s and improved in
1990’s.
It is a digital network which is to transmit voice, image, video and text over the existing
circuit – switched PSTN telephone network.
Swapnali Pawar
38

39. Interfaces used for GSM network:
1) UM Interface – Used to communicate between BTS with MS
2) Abis Interface — Used to communicate BSC TO BTS
3) A Interface — Used to communicate BSC and MSC
4) Singling protocol (SS 7) — Used to communicate MSC with
other network .
Swapnali Pawar
39

40. GSM Services
GSM offers much more than just voice telephony. GSM offers three
basic types of services −
• Telephony services or teleservices
• Data services or bearer services
• Supplementary services
Swapnali Pawar
40

41. • Voice Calls
The most basicTeleservice supported by GSM is telephony.This includes full-rate speech at 13
kbps and emergency calls, where the nearest emergency-service provider is notified by dialing
three digits.
• Videotext and Facsmile
Another group of teleservices includesVideotext access,Teletex transmission, Facsmile
alternate speech and Facsmile Group 3,Automatic Facsmile Group, 3 etc.
• ShortText Messages
Short Messaging Service (SMS) service is a text messaging service that allows sending and
receiving text messages on your GSM mobile phone. In addition to simple text messages,
other text data including news, sports, financial, language, and location-based data can also be
transmitted.
• MMS (Multimedia messaging services) –Send photos,
images, screen savers, videos, wallpapers etc
• VAS-Value Added Services
• Location-based services (LBS): Mobile applications
Mobile location-based services use the geographic location of a personal handset – such as a
personal digital assistant (PDA), smart phone or navigation device – either to enhance existing
applications or to enable new applications
GSM Services
Swapnali Pawar
41

42. • Bearer Services
Data services or Bearer Services are used through a GSM phone. to receive and send data is the essential
building block leading to widespread mobile Internet access and mobile data transfer. GSM currently has a
data transfer rate of 9.6k. New developments that will push up data transfer rates for GSM users are
HSCSD (high speed circuit switched data) and GPRS (general packet radio service) are now available.
• Supplementary Services
Supplementary services are additional services that are provided in addition to teleservices and bearer
services.These services include caller identification, call forwarding, call waiting, multi-party
conversations, and barring of outgoing (international) calls, among others.A brief description of
supplementary services is given here −
• Conferencing − It allows a mobile subscriber to establish a multiparty conversation, i.e., a
simultaneous conversation between three or more subscribers to setup a conference call.This service
is only applicable to normal telephony.
• CallWaiting −This service notifies a mobile subscriber of an incoming call during a conversation.
The subscriber can answer, reject, or ignore the incoming call.
• Call Hold −This service allows a subscriber to put an incoming call on hold and resume after a
while.The call hold service is applicable to normal telephony.
• Call Forwarding − Call Forwarding is used to divert calls from the original recipient to another
number. It is normally set up by the subscriber himself. It can be used by the subscriber to divert calls
from the Mobile Station when the subscriber is not available, and so to ensure that calls are not lost.
• Call Barring − Call Barring is useful to restrict certain types of outgoing calls such as ISD or stop
incoming calls from undesired numbers. Call barring is a flexible service that enables the subscriber to
conditionally bar calls.
• Number Identification
Swapnali Pawar
42

43. • Advice of Charge (AoC) −
This service was designed to give the subscriber an indication
of the cost of the services as they are used. Furthermore, those
service providers who wish to offer rental services to
subscribers without their own SIM can also utilize this service
in a slightly different form.AoC for data calls is provided on
the basis of time measurements.
• Closed User Groups (CUGs) −
This service is meant for groups of subscribers who wish to
call only each other and no one else.
• Unstructured supplementary services data (USSD) −
This allows operator-defined individual services.
GSM Services
Swapnali Pawar
43

44. Different Modes used for Mobile Communication
1. Satellite Communication. Satellite
communication is a crucial form of wireless
communication.
2. Infrared Communication.
3. Broadcast Radio. ...
4. Microwave Communication.
5. Wi-Fi.
6. Mobile Communication Systems.
7. BluetoothTechnology.etc.
Swapnali Pawar
44

45. 1. Satellite Communication
• Satellite communication is a crucial form of wireless communication. By means of
satellites, people all over the earth can communicate with each other.
• It may not be possible to send a signal to another country because, well, the curvature of
the earth is in the way.This is one reason why satellites are orbiting the earth because they
can send a signal amongst themselves and eventually to the distant country.All of this at an
incredibly fast speed.
• NASA and other space agencies make regular use of this type of technology. Of course,
sending a satellite into the atmosphere is not cheap.Therefore the technology involved must
be subjected to significant testing before launch.
Swapnali Pawar
45

46. 2. Infrared Communication
• Infrared communication is present in most homes in the form of a television
remote control. However, how does it work?
• IR transmits information by means of invisible light.This means that on the
electromagnetic spectrum it lies between microwaves and visible light.
• Infrared communication requires a transmitter and a photoreceiver to
receive the light beam. Since any disruption to the light will result in the
photoreceiver not receiving it, IR will only function when there is a line of
sight visibility.That means that if you stand between the transmitter and
receiver it will probably not work
Swapnali Pawar
46

47. 3. Broadcast Radio
• The most famous form of wireless transmission on our list, broadcast radio, was probably
the first kind of wireless communication.
• Radio transmitters send out data in the form of radio waves to receiving antennae. Radio
waves are forms of electromagnetic signals. Signals are relatively narrow, and waves
can be sent across various frequencies.This is why your car radio is able to receive signals
from many different radio stations.
• There are many types of users of radio communication. Radio stations that send out
informative and entertaining programs. Maritime radio channels allow ships to
communicate with each other and the shore. Ham radio enthusiasts are able to
communicate and use radio communication for personal use.
Swapnali Pawar
47

48. 4. Microwave Communication
Microwave technology is an effective type of communication that is used globally.This
technology can be broken down into 2 types
Satellite Microwave Communication
This is the most effective method of transmitting microwaves globally. Like Infrared
technologies, Microwave technologies require a clear line of sight.This means that if you
want to send a signal over a long distance, sending it up to a satellite first is a good idea.
The only problem is that in very dense cloudy weather the signal to the satellite can be
blocked by atmospherics.
Terrestrial Microwave Communication
Microwave technologies can be a very secure form of communication. If a signal needs to be
transmitted over a short distance, it can be enough to erect two antennae with a clear line of
sight.The signal can then be transmitted between the two receivers. This negates the need to
connect to an outside network.
Swapnali Pawar
48

49. 5.Wi-Fi
Wi-Fi internet is a low powered wireless electronic network.These are
available in almost every shopping mall and cafe in the world. Essentially a
physical wired network is connected to a router.This creates a highly
localized and low power wireless network.
From this, it is possible to connect a range of devices to the local network.
However, public wireless internet access is known to be a target for thieves
and hackers.Therefore, it is essential that both users who connect to these
networks and the providers use password protection defense methods.
Swapnali Pawar
49

50. 6. Mobile Communication Systems
The mobile phone industry uses similar technology toWi-Fi but on a much
grander and safer scale. Mobile phone companies provide coverage to
customers nationwide or even international scale.
They do this by means of a complex blend of local networks and
transmitters together with satellite support.
Swapnali Pawar
50

51. 7. BluetoothTechnology
Bluetooth is a relatively new technology but is becoming more and more
prevalent. It is essentially a simple method to send information across a short
distance. However, this information can include either messages or even files.
Bluetooth technology was originally designed to be a replacement for physical
cables. However, it does have its downsides. It has a maximum reach of 30 feet.
This can be reduced further, but not entirely blocked by walls and other solid
items.
Swapnali Pawar
51

52. Architecture Of mobile Computing 3Tier
Swapnali Pawar
52

53. Swapnali Pawar
53

54. Mobile Computing Architecture
Swapnali Pawar
54

55. A 3-tier architecture is an application program
that is organized into three major parts,
comprising of-
• The data access layer tier (Data Layer) at the
bottom
• The application tier (business logic) in the
middle
• The client tier (presentation) at the top.
Mobile Computing Architecture 3Tier
Swapnali Pawar
55

56. Each tier is distributed to a different place or
places in a network.These tiers do not necessarily
correspond to physical locations on various computers on
a network, but rather to logical layers of the application.
1. Presentation Layer (UI)
• This layer presents data to the user and optionally
permits data manipulation and data entry, also this
layer requests the data form Business layer.
• This layer accomplished through use of Dynamic
HTML and client-side data sources and data cursors.
Swapnali Pawar
56

57. 2. Business Logic Layer
• The business logic acts as the server for client requests
from workstations. It acts according Business rules fetch
or insert data through the Data Layer.
• In turn, it determines what data is needed and
where it is located and acts as a client in relation to a
third tier of programming that might be located on a local
or mainframe computer.
• Because these middle-tier components are not tied to a
specific client, they can be used by all applications and can
be moved to different locations, as response time and
other rules require.
Swapnali Pawar
57

58. 3. Data Access Layer
• The third tier of the 3-tier system is made up of
the DBMS that provides all the data for the above
two layers.
• This is the actual DBMS access layer.
• Avoiding dependencies on the storage mechanisms
allows for updates or changes without the
application tier clients being affected by or even
aware of the change.
Swapnali Pawar
58

59. Swapnali Pawar
59