UNIT 4

TOPICS INCLUDE

Data Management Issues, Data Replication For Mobile Computers, Adaptive

Clustering for Mobile Wireless Networks, File System, Disconnected Operations,
Data Services in GPRS - Applications for GPRS - Limitation

Disconnected Operations, Data Services in

GPRS - Applications for GPRS - Limitations

1.Data Management Issues

Data management in mobile computing presents unique challenges due
to the nature of mobile devices and the environments in which they
operate. Here are some key issues:

1. Data Security and Privacy

 Device Vulnerability: Mobile devices are often more vulnerable to

theft, loss, and unauthorized access, which can compromise
sensitive data.

 Insecure Networks: Mobile devices frequently connect to public or

untrusted networks, increasing the risk of data breaches and man-
in-the-middle attacks.

 App Permissions: Mobile apps often request access to sensitive

data, and users may inadvertently grant permissions that
compromise their privacy.

2. Data Synchronization

 Inconsistent Data: Ensuring that data remains consistent across

multiple devices and platforms is challenging, especially when
network connectivity is unreliable.
  Real-time Updates: Keeping data synchronized in real-time across
devices, especially when switching between online and offline
modes, can be difficult.

3. Data Storage

 Limited Storage Capacity: Mobile devices have limited storage

compared to desktops or servers, making it necessary to manage
data efficiently.

 Data Retention: Balancing the need to retain data for user access
with the constraints of storage capacity can be challenging.

4. Battery Consumption

 Energy-Intensive Processes: Data management tasks such as

synchronization, encryption, and backups can drain battery life,
reducing the usability of mobile devices.

 Resource Optimization: Efficiently managing data to minimize

battery consumption without sacrificing performance is a key
challenge.

5. Network Connectivity

 Intermittent Connectivity: Mobile devices often experience

intermittent or poor network connectivity, leading to delays in data
access, synchronization, and backup.

 Data Transfer Costs: Transferring large amounts of data over

mobile networks can be costly for users, especially in regions with
limited or expensive data plans.

6. Data Accessibility and Usability

 User Interface Limitations: The smaller screen size and limited

input methods on mobile devices can make it difficult to access and
manage data effectively.
  Cross-Platform Access: Ensuring that data is accessible and usable
across different mobile operating systems (iOS, Android) and
devices can be complex.

7. Data Integrity

 Corruption Risks: Mobile devices are more prone to data corruption

due to sudden shutdowns, crashes, or unstable environments.

 Error Handling: Ensuring data integrity through robust error

detection and correction mechanisms is crucial in mobile
computing.

8. Compliance and Regulation

 Data Protection Laws: Ensuring compliance with data protection

regulations (e.g., GDPR) is more complex on mobile devices due to
the diversity of apps and platforms.

 Location-Based Restrictions: Mobile devices often collect location

data, which may be subject to specific regulations and require
careful management.

9. Data Backup and Recovery

 Cloud Dependency: Many mobile devices rely on cloud services for

backup, which introduces dependency on external providers and
potential security risks.

 Offline Backup: Providing reliable backup solutions when the device

is offline or in low-connectivity areas can be difficult.

10. Scalability

 Handling Growing Data Volumes: As mobile applications collect

more data, managing and scaling storage and processing capabilities
on mobile devices become increasingly challenging.
  Performance: Ensuring that data management processes do not
degrade the performance of mobile apps is critical for user
experience.

2. Data Replication For Mobile Computers

Data Replication

Data Replication in mobile computing means the sharing of information to

ensure data consistency between software and hardware resources connected
via the internet, to improve reliability, availability, fault-tolerance, and
accessibility of data.

In simpler terms, data replication is the process of storing different copies of

the database at two or more sites in order to improve data availability in less
time and at a cheaper cost.

Data replication in mobile computing is a popular fault tolerance technique

for distributed databases.

Advantages of Data Replication

In modern mobile computing, scenario data replication has been adopted as

an efficient way to ensure data availability, integrity, and an effective means to
achieve fault tolerance. Data replication not only ensures the availability of the
data but also minimize the communication cost, increase data sharing, and
enhance the security of sensitive data. Data replication in mobile computing
also determines when and which location to store the replica of data,
controlling different data replicas over a network for efficient utilization of the
network resources.

Data Replication Benefits

Important benefits of data replication are as below-

 Reliability − Data replication provides the reliability of data. In case of failure
of any site, the database system continues to work since a copy is available at
another site(s).
 Reduction in Network Load − since local copies of data are available
through data replication. Therefore, query processing can be done
with reduced network usage, particularly during prime hours.
 Data updating can be done at non-prime hours – Due to data
replication data can be updated easily.
 Quicker Response − Availability of local copies of data ensures quick query
processing and consequently quick response time.
 Simpler Transactions − Transactions require less number of joins of tables
located at different sites and minimal coordination across the network.
Thus, they become simpler in nature.

Disadvantages of Data Replication

 Increased Storage Requirements − Maintaining multiple copies of data is

associated with increased storage costs. The storage space required is in
multiples of the storage required for a centralized system.
 Increased Cost and Complexity of Data Updating − each time a data item is
updated, the update needs to be reflected in all the copies of the data at
the different sites. This requires complex synchronization techniques and
protocols.

Goals of data replication

Data replication is performed with the purpose of

 Increasing the availability of data.

 Speeding up the query evaluation.

Types of data replication

There are two types of data replication

1. Synchronous Replication
In synchronous replication, the replica of the database is modified immediately
after changes are made in the relation table.

So there is no difference between the original data and the replicated data table
 2. Asynchronous replication
In asynchronous replication, the replica will be modified after commit action is
fired on to the database

Replication Schemes

The three replication schemes are as follows:

1. Full Replication scheme

In full replication scheme, the database is available at all the locations to ease
the user in the communication network

Advantages of full replication

 It gives high availability of data. In this scheme, the database is available at each
location.
 It supports faster execution of queries.

Disadvantages of full replication

 In a full replication scheme, concurrency control is difficult to achieve in full

replication.
 During updating each and every side need to be updated therefore update
operation is slower.

2. No Replication

No replication means each fragment is stored exactly at one location only.

Advantages of no replication

 Concurrency can be easily minimized.

 Easy recovery of data becomes easy.

Disadvantages of no replication

 Poor availability of data.

 Slows down the query execution process, because multiple clients are
accessing the same data at the same server.

3. Partial replication

A partial replication scheme means only part of the or data fragments are
replicated.
3.Adaptive clustering in mobile wireless
networks
Personal communications and mobile computing require a wireless network
infrastructure which is fast deployable, possibly multihop, and capable of
multimedia service support. The first infrastructure of this type was the Packet
Radio Network (PRNET), developed in the 70’s to address the battlefield and
disaster recovery communication requirements. PRNET was totally
asynchronous and was based on a completely distributed architecture. It
handled datagram traffic reasonably well, but did not offer efficient
multimedia support. Recently,

under the WAMIS (Wireless Adaptive Mobile Information Systems) and Glomo
ARPA programs several mobile, multimedia, multihop (M3 ) wireless network
architectures have been developed, which require some form of synchronous, time
division infrastructure. The synchronous time frame leads to efficient multimedia
support implementations. However, it introduces more complexity and is less
robust in the face of mobility and channel fading. Clearly there are complexity vs
performance tradeoffs in introducing various degrees of synchronization into the
network. Figure 1, shows the cellular model commonly used in the wireless
networks. A, B, C, and D are fixed base stations connected by a wired backbone.
Nodes 1 through 8 are mobile nodes. A mobile node is only one hop away from a
base station. Communications between two mobile nodes must be through fixed
base stations and the wired backbone.
 Figure 1: Conventional cellular networks (single-hop)
In parallel with (and separately from) the single hop cellular model, another
type of model, based on radio to radio packet multihopping, has been
emerging to serve a growing number of applications which rely on a fast
deployable, wireless infrastructure. The classic examples are battlefield
communications and (in the civilian sector) disaster recovery (fire, earthquake)
and search and rescue. A recent addition to this set is the ‘‘adhoc’’ personal
communications network, which could be rapidly deployed on a campus, for
example, to support collaborative computing and access to the Internet during
special events (concerts, festivals etc). Multihopping through wireless
repeaters strategically located on campus permits to reduce battery power and
to increase network capacity. More precisely, by carefully limiting the power of
radios, we conserve battery power. Furthermore, we also cause less
interference to other transmissions further away; this gives the additional

benefit of ‘‘spatial reuse’’ of channel spectrum, thus increasing the capacity of

the system. Interestingly, the multihop requirement may also arise in cellular
networks. If a base station fails, a mobile node may not be able to access the
wired network in a single hop. For example, in Figure 2, if base station B fails,
node 4 must access base stations A or C through node 2 or node 5 which act as
wireless multihop repeaters.

Figure 2: A multihop situation occurs when base

station B fails.
In order to support multimedia traffic, the wireless network layer must
guarantee QoS (band- width and delay) to real time traffic components.
Our approach to provide QoS to multimedia consists of the following two
steps: (a) partitioning of the multihop network into clusters, so that
controlled, accountable bandwidth sharing can be
accomplished in each cluster; (b) establishment of Virtual Circuits with QoS
guarantee.
The objective of the clustering algorithm is to partition the network into
several clusters. Optimal cluster size is dictated by the tradeoff between
spatial reuse of the channel (which drivestoward small sizes), and delay
minimization (which drives towards large sizes). Other constraints also
apply, such as power consumption and geographical layout. Cluster size
is controlled through the radio transmission power. For the cluster
algorithm, we have so far assumed that transmission power is fixed and
is uniform across the network.
Within each cluster, nodes can communicate with each other in at
most two hops. The clusters can be constructed based on node ID. The
following algorithm partitions the multihop network into some non-
overlapping clusters. We make the following operational assumptions
underlying the construction of the algorithm in a radio network. These
assumptions are common to most radio data link protocols.
A1: Every node has a unique ID and knows the IDs of its 1-hop
neighbors. This can be provided by a physical layer for mutual
location and identification of radio nodes.
A2: A message sent by a node is received correctly within a finite time
by all its 1- hop neighbors.
A3: Network topology does not change during the algorithm execution.
We can find from this algorithm that each node only broadcasts one
cluster message before the algorithm stops, and the time complexity is
O(|V |) where V is the set of nodes. The clustering algorithm converges
very rapidly. In the worst case, the convergence is linear in the total
number of nodes. Consider the topology in Figure 3. After clustering, in
Figure 4,we can find six clusters in the system, which are
{1,2}, {3,4,11}, {5,6,7,8,9}, {10,12,13},{14,15,16,17}, {18,19,20}. To prove
the
correctness of the algorithm we have to show that: 1) every node
eventually determines its cluster; 2) in a cluster, any two nodes are at
most two hops away; 3) the algorithm terminates.
12
13 14
11
10 16

20
19 18

Figure 3: System topology

 Figure 4: Clustering

4 What is a File System?

A file system is a process of managing how and where data on a storage disk, which
is also referred to as file management or FS. It is a logical disk component that
compresses files separated into groups, which is known as directories. It is abstract
to a human user and related to a computer; hence, it manages a disk's internal
operations. Files and additional directories can be in the directories. Although there
are various file systems with Windows, NTFS is the most common in modern times.
It would be impossible for a file with the same name to exist and also impossible to
remove installed programs and recover specific files without file management, as
well as files would have no organization without a file structure. The file system
enables you to view a file in the current directory as files are often managed in a
hierarchy.
A disk (e.g., Hard disk drive) has a file system, despite type and usage. Also, it
contains information about file size, file name, file location fragment information,
and where disk data is stored and also describes how a user or application may
access the data. The operations like metadata, file naming, storage management,
and directories/folders are all managed by the file system.

On a storage device, files are stored in sectors in which data is stored in groups of
sectors called blocks. The size and location of the files are identified by the file
system, and it also helps to recognize which sectors are ready to be used. Other
than Windows, there are some other operating systems that contain FAT and NTFS
file system. But Apple product (like iOS and macOS) uses HFS+ as operating system
is horizon by many different kinds of file systems.

Sometimes the term "file system" is used in the reference of partitions. For
instance, saying, "on the hard drive, two files systems are available," that does not
have to mean the drive is divided between two file systems, NTFS and FAT. But it
means two separate partitions are there that use the same physical disk.

In order to work, a file system is required by most of the applications you come into
contact with; therefore, each partition should have one. Furthermore, if a program
is built for use in macOS, you will be unable to use this program on windows
because programs are file system-dependent.

Examples of file systems

The examples of file systems are given below:

FAT: FAT is a type of file system, which is developed for hard drives. It stands for file
allocation table and was first introduced in 1977, which is used for 12 or 16 bits for
each and every cluster access into the file allocation table (FAT). On hard drives and
other computer systems, it helps to manage files on Microsoft operating systems. In
devices like digital cameras, flash memory, and other portable devices, it is also
often found that is used to store file information. It also helps to extend the life of a
hard drive as it minimizes the wear and tears on the hard disc. Today, FAT is not
used by later versions of Microsoft Windows like Windows XP, Vista, 7, and 10 as
they use NTFS. The FAT8, FAT12, FAT32, FAT16 are all the different types of FAT (for
file allocation table).

GFS: A GFS is a file system, which stands for Global File System. It has the ability to
make enable multiple computers to act as an integrated machine, which is first
developed at the University of Minnesota. But now it is maintained by Red Hat.
When the physical distance of two or more computers is high, and they are unable
to send files directly with each other, a GFS file system makes them capable of
sharing a group of files directly. A computer can organize its I/O to preserve file
systems with the help of a global file system.

HFS: HFS (Hierarchical file system) is the file system that is used on a Macintosh
computer for creating a directory at the time a hard disk is formatted. Generally, its
basic function is to organize or hold the files on a Macintosh hard disk. Apple is not
capable of supporting to write to or format HFS disks since when OS X came on the
market. Also, HFS-formatted drives are not recognized by Windows computers as
HFS is a Macintosh format. With the help of WIN32 or NTFS file systems, Windows
hard drives are formatted.

NTFS: NTFS is the file system, which stands for NT file system and stores and
retrieves files on Windows NT operating system and other versions of Windows like
Windows 2000, Windows XP, Windows 7, and Windows 10. Sometimes, it is known
as the New Technology File System. As compared to the FAT and HPFS file system, it
provides better methods of file recovery and data protection and offers a number of
improvements in terms of extendibility, security, and performance.

UDF: A UDF is a file system, stands for Universal Disk Format and used first
developed by OSTA (Optical Storage Technology Association) in 1995 for ensuring
consistency among data written to several optical media. It is used with CD-ROMs
and DVD-ROMs and is supported on all operating systems. Now, it is used in the
process of CD-R's and CD-RW's, called packet writing.

Architecture of the File System

Two or three layers are contained by the file system. Sometimes, these layers
function combined and sometimes are explicitly separated. For file operations, the
API (Application Program Interface) is provided by the logical file system, like OPEN,
CLOSE, READ, and more because it is accountable for interaction with the user
application. Also, for processing, the requested operation is forwarded to the layer
that is located below it. Furthermore, for various concurrent instances of physical
file systems, the second optional layer allows support, which is a virtual file system.
And each concurrent instance is called a file system implementation.

The third layer is responsible for handling buffering and memory management,
which is called the physical file system. It is concerned with the physical operation
of the storage device and processes physical blocks being read or written.
Furthermore, to drive the storage device, this layer interacts with the channel and
the device drivers.
Types of file systems

There are various kinds of file systems, which are as follows:

1. Disk file systems

On the disk storage medium, a disk file system has the ability to randomly address
data within a few amounts of time. Also, it includes the anticipation that led to the
speed of accessing data. Without regard to the sequential location of the data,
multiple users can access several data on the disk with the help of a disk file system.

2. Flash file systems

A flash file system is responsible for restrictions, performance, and special abilities
of flash memory. It is superior to utilize a file system that is designed for a flash
device; however, a disk file system is the basic storage media, which can use a flash
memory device.

3. Tape file systems

A tape file system is used to hold files on the tape as it is a tape format and file
system. As compared to disks, magnetic tapes are more powerful to access data for
a long time, which are the challenges for a general-purpose file system in terms of
creation and efficient management.

4. Database file systems

A database-based file system is another method for file management. Files are
recognized by their characteristics (like a type of file, author, topic, etc.) rather than
hierarchical structured management.

5. Transactional file systems

Some programs require one or more changes to fail for any reason or need several
file systems changes but do not make any changes. For instance, a program may
write configuration files or libraries mand executables at the time of installing or
updating the software. The software may be unusable or broken if the software is
stopped while updating or installing. Also, the entire system may leave in an
unusable state if the process of installing or updating the software is incomplete.

6. Network file systems

A network file system offers access to files on a server. In remote network-

connected computers, with the help of local interfaces, programs are able to
transparently create, manage and access hierarchical files and directories. The file-
system-like clients for FTP and WebDAV, and AFS, SMB protocols, NFS are all
examples of the network file systems.

7. Shared disk file systems

A shared-disk file system allows the same external disk subsystem to be accessed by
multiple machines, but when the number of machines accesses the same external
disk subsystem, there may be occurred collisions in this condition; so, to prevent the
collision, the file system decides which subsystem to be accessed.

8. Minimal file system

In the 1970s, for some initial microcomputer users, disk and digital tape devices
were much expensive. A few cheaper basic data storage systems used common
audio cassette tape was designed. On the cassette recorder, the user was informed
about pressing "RECORD" when there was required to write data by system. And, to
notify the system, press "RETURN" on the keyboard. Also, on the cassette recorder,
the user was needed to press the "PLAY" button when the system required to read
data.

9. Flat file systems

The subdirectories are not available in the flat system. It contains the only directory,
and all files are held in a single directory. Due to the relatively small amount of data
space available, this type of file system was adequate when floppy disk media was
available for the first time.

5.DISCONNECTED OPERATION IN MOBILE

COMPUTING
Disconnected operation in mobile computing refers to the ability of a mobile device
or system to continue functioning and providing services even when it is not
connected to a central network or server. This capability is particularly important in
scenarios where network connectivity is intermittent, unreliable, or completely
unavailable. Disconnected operation is essential for ensuring that mobile
applications and services remain functional, providing a seamless user experience
despite connectivity issues.

Key Aspects of Disconnected Operation

1. Local Data Caching and Storage:

 o Mobile devices often store data locally to ensure continued operation
when disconnected. This may include user data, application states, and
any other critical information that needs to be available offline. When
connectivity is restored, this data can be synchronized with the central
server.

2. Optimistic Replication:

o Optimistic replication is a technique used in disconnected operations

where updates made by the user are saved locally and later reconciled
with the server when the connection is re-established. Conflicts may
arise when multiple users update the same data, which are typically
resolved using various conflict resolution strategies.

3. Lazy Propagation:

o Changes made while the system is offline are propagated to the server
lazily, meaning that synchronization happens only when the device
reconnects. This reduces the need for immediate data consistency,
prioritizing availability and usability.

4. Pre-fetching:

o Some mobile systems anticipate potential disconnections by pre-

fetching necessary data before the device goes offline. This ensures
that the user has access to critical data during the period of
disconnection.

5. Context-Aware Computing:

o Disconnected operation may involve context-aware mechanisms that

adjust the behavior of applications based on the current connectivity
status. For example, an app might switch to a low-bandwidth mode or
prioritize essential functions when a disconnection is detected.

Applications of Disconnected Operation

1. Mobile Databases:

o Mobile databases often support disconnected operations by allowing

users to query and update the database locally. These updates are later
synchronized with a central database.

2. File Synchronization Services:

 o Services like Dropbox or Google Drive allow users to access and modify
files offline. Changes are synced once the device is back online.

3. Email Clients:

o Many email clients, such as Outlook or Gmail, support offline mode,

enabling users to read, compose, and organize emails without an
internet connection. Emails are sent and updates are synced when the
connection is restored.

4. Offline Navigation:

o GPS navigation apps, like Google Maps or offline maps apps, allow
users to download maps and use them without an internet connection,
which is particularly useful in areas with poor connectivity.

5. Cloud Storage:

o Cloud storage services often allow users to mark files for offline access.
These files can be edited or viewed, and changes are synced back to
the cloud when the device reconnects.

Challenges

 Data Consistency: Ensuring that data remains consistent across multiple

devices and users when they reconnect is a significant challenge.

 Conflict Resolution: When multiple disconnected devices make changes to

the same data, conflicts can occur, which need to be resolved, often requiring
sophisticated algorithms.

 Resource Constraints: Mobile devices have limited storage, processing

power, and battery life, which can constrain the extent to which disconnected
operations are supported.

Conclusion

Disconnected operation is a critical feature for enhancing the resilience and

usability of mobile systems. By allowing continued functionality in the absence of
network connectivity, it ensures that users can rely on their devices and applications
regardless of their connectivity status

OR
Disconnected operation in mobile computing refers to the ability of a mobile device
or system to continue functioning without a continuous connection to a central
server or network. This feature is essential for mobile environments where network
connectivity can be intermittent, unreliable, or completely unavailable. The concept
allows users to continue working with local data and services, with changes and
updates synchronized when connectivity is restored.

Key Concepts

1. Local Data Caching:

o Data required for operation is stored locally on the mobile device,

allowing users to access and modify information even when offline.
Once the connection is re-established, any changes are synchronized
with the central server.

2. Data Synchronization:

o Synchronization is the process of reconciling data between the mobile

device and the server. It typically happens automatically when the
device reconnects to the network, ensuring that both the local and
central data repositories are consistent.

3. Conflict Resolution:

o When multiple users work on the same data offline and later
synchronize with the server, conflicts can arise. Conflict resolution
mechanisms are used to determine which version of the data is
authoritative or how to merge changes.

4. Optimistic Replication:

o In this approach, updates made by the user are stored locally and are
assumed to be valid. The updates are propagated to the central server
once the connection is restored. If conflicts occur, they are resolved
later.

5. Pre-fetching Data:

o Before going offline, some systems pre-fetch data that is likely to be

needed during the disconnected period. This ensures the availability of
critical information while offline.
Applications

1. Mobile Databases:

o Mobile databases allow users to query and update data even when
disconnected from the network. These changes are synchronized with
the main database once connectivity is restored.

2. Offline File Access:

o Applications like Google Drive or Dropbox allow users to mark files for
offline access. Users can edit these files without an internet connection,
and the changes are synced back to the cloud when they reconnect.

3. Email Clients:

o Email clients like Outlook or Gmail enable users to read, compose, and
organize emails offline. The emails are sent and changes are synced
when the connection is available again.

4. Offline Navigation:

o GPS applications, such as Google Maps, provide offline navigation by

allowing users to download maps ahead of time. This is particularly
useful in areas with poor connectivity.

5. Cloud-based Applications:

o Many cloud-based apps have offline modes that allow users to work
without an internet connection. Data and changes are later synced with
the cloud service.

Challenges

 Data Consistency:

o Ensuring data consistency between local and central stores can be

challenging, especially when multiple users make offline changes.

 Resource Constraints:

o Mobile devices have limited storage, processing power, and battery

life, which can limit the extent and efficiency of disconnected
operations.

 Conflict Management:
 o Managing conflicts that arise during synchronization requires
sophisticated algorithms and can be complex, particularly in
collaborative environments.

Conclusion

Disconnected operation is a vital feature in mobile computing that enhances

usability and resilience in environments with unreliable or intermittent connectivity.
By allowing users to continue working offline and ensuring that data is synchronized
later, it provides a seamless experience across different network conditions.

6.Data Services in GPRS

1. Internet Access (Web Browsing)

o GPRS allows mobile devices to access the internet, enabling users to

browse websites. This service supports basic web activities such as
searching, reading news, and social networking.

2. Email Services

o With GPRS, users can send and receive emails on their mobile devices.
This service supports various email protocols, including POP3, IMAP,
and SMTP, allowing for synchronization with email servers.

3. Multimedia Messaging Service (MMS)

o GPRS supports MMS, which allows users to send messages that include
multimedia content such as images, audio, and video, in addition to
text.

4. Instant Messaging and Chat

o GPRS enables real-time communication through instant messaging

applications. Users can engage in text-based conversations with others
using apps that rely on GPRS for data transmission.

5. File Transfer Protocol (FTP)

o GPRS can be used for file transfers, allowing users to download and
upload files to and from remote servers. This service is crucial for
applications that require the exchange of files, such as document
management systems.
 6. WAP (Wireless Application Protocol) Services

o GPRS facilitates access to WAP services, which are designed for

delivering internet content to mobile devices. WAP services include
browsing WAP-enabled websites and using WAP-based applications.

7. Location-Based Services (LBS)

o GPRS supports location-based services, which provide information and

services based on the user's geographic location. Examples include
navigation apps, local search services, and location-based advertising.

8. Push-to-Talk over Cellular (PoC)

o PoC is a communication service that allows users to use their mobile

devices like walkie-talkies, enabling instant voice communication with
individuals or groups.

9. Corporate Network Access (VPN)

o GPRS can be used to establish a Virtual Private Network (VPN)

connection, enabling secure access to corporate networks for remote
workers. This service is essential for accessing company resources and
conducting business activities while on the move.

10.Telematics

o GPRS is widely used in telematics applications, which involve the

transmission of data from remote devices. This includes vehicle
tracking, remote monitoring of machinery, and other machine-to-
machine (M2M) communications.

Advantages of GPRS Data Services

 Always-On Connectivity: Unlike traditional circuit-switched networks, GPRS

provides an always-on connection, allowing users to remain connected to
data services without needing to dial in each time.

 Cost-Effective: GPRS charges are typically based on the amount of data

transmitted rather than the duration of the connection, making it more cost-
effective for users.

 Higher Data Rates: GPRS offers higher data transmission rates compared to
earlier technologies, with speeds typically ranging from 56 to 114 kbps,
enabling a better user experience for data services.
Limitations of GPRS Data Services

 Limited Speed: Although GPRS offers improved data rates compared to

earlier technologies, it is still relatively slow by modern standards, especially
compared to 3G, 4G, and 5G networks.

 Latency: GPRS networks can experience higher latency, which can impact the
performance of real-time applications such as video calls and online gaming.

 Coverage: GPRS is dependent on the underlying 2G or 3G network coverage,

which may not be available in all areas, especially rural or remote regions.

GPRS

Introduction

GPRS is an acronym for General Packet Radio Service. This technology allows
information to be sent back and forth across a mobile network. It is an addition to
today's circuit switched data and Short message services.

GPRS is an expansion Global System for Mobile Communication. It is basically a

packet-oriented mobile data standard on the 2G and 3G cellular communication
network’s global system for mobile communication. GPRS was built up by European
Telecommunications Standards Institute (ETSI) because of the prior CDPD, and I-
mode packet switched cell advances.

GPRS overrides the wired associations, as this framework has streamlined access to
the packet information’s network like the web. The packet radio standard is utilized
by GPRS to transport client information packets in a structured route between GSM
versatile stations and external packet information networks. These packets can be
straightforwardly directed to the packet changed systems from the GPRS portable
stations.

Features of GPRS

 Speed : The maximum theoretical speed that can be achieved is up to 171.2

kilobytes per second (kbps) using all the eight timeslots at the same time.

 Instantaneous : GPRS lets you stay connected as Information can be sent or

received immediately as the need arises, depending on the strength and
coverage.
  Application Development: GPRS lets mobile application developers develop
newer, faster and better mobile applications that haven't been available due
to previous technology speed limitations. Applications that have been
developed for a GPRS enabled mobile phone range from the basic browser
for surfing the internet to online chat applications, file transfer applications
and so on.

Requirements to Use GPRS

To use GPRS, there are some pre-requisites that you need to satisfy.

 Primarily, you should have a GPRS enabled phone. Phones such as the Nokia
7610 and the Motorola A80 have a GPRS functionality. There are many other
available from different vendors.

 Ensure that your service provider also provides GPRS service.

 You should also take care of the data charges levied by the service as data is
downloaded on to your phone when you browse the internet. Another factor
is knowing how to access and use the GPRS functionality in your phone.

Limitations

No new technology is foolproof and there are downsides. Even in all the new and
exciting features that go into making GPRS one of the most accessible technologies
for the common person, there are some large limitations.

 Overloading : GPRS as a technology means a newer and faster way for

transferring data and as with all networks, data transfer consumes bandwidth
and clogs the networks, data transfer consumes bandwidth and clogs the
network. voice and GPRS data transfer are bound to affect network
performance. Similar to the "Network Not Available" Message that you may
sometimes receive when trying to make a call at peak hours, data transfer
speeds are also affected during peak hours. While GPRS and voice channels
use the same network resources, the GPRS technology is intelligent to
manage or allocate the channels dynamically allowing a reduction in peak
tome signaling channel loading by sending short messages over GPRS
channels instead.

 Lower Speeds : The theoretical speed of the GPRS data transmission speed is
172.2 kbps but this is only possible in a scenario when one single user without
any error protection is hogging all the timeslots. Any service provider will
obviously not allow this and in all probability you will be able to access only
 one or two time slots that will be able to access only one or two time slots
that will limit the amount of bandwidth available to you. This translates into
lower data transmission speeds.

 No Store and Forward Mechanism : The main advantage of SMS is the store
and Forward mechanism. What this essentially means is that any SMS that
you send using your mobile first goes to cenral server and is then forwarded
to the destination phone number. In case that number is switched off or
unavilable, the message is stored on the server for some amount of time. This
is absent in the GPRS standard.

 Data Transit Speeds : GPRS data transfer takes place using a simple principle.
Data sent from the sender is transmitted to the recipient using different
paths. The probability of the data being lost or corrupted during transit is high
and hence the GPRS standard includes data integrity and retransmission
strategies. Nevertheless, due to this, potential transit delays can occur and
hence a better, faster standard needs to be implemented.
Figure 4: Clustering