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Mobile Database SystemsMobile Database Systems
Technical seminor Presented by
p . nageshmca final year
08k91f0020
tkrcet
meerpet,hyd
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Mobile Database SystemsMobile Database Systems
Outline
Fully Connected Information Space
Personal Communication System (PCS)
Mobile Database Systems (MDS)
Transaction Management
Data Caching
Query Processing
Conclusion
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Mobile Database SystemsMobile Database Systems
Fully connected information spaceFully connected information space
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Mobile Database SystemsMobile Database Systems
Fully connected information space
Each node of the information space has some
communication capability.
Some node can process information.
Some node can communicate through voice
channel.
Some node can do both
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Mobile Database SystemsMobile Database Systems
Fully connected information space
Can be created and maintained by integrating
legacy database systems, and wired and wireless
systems (PCS, Cellular system, and GSM)
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Mobile Database SystemsMobile Database Systems
A system with the following structural and functional
properties
Distributed system with mobile connectivity
Full database system capability
Complete spatial mobility
Built on PCS/GSM platform
Wireless and wired communication capability
What is a Mobile Database System (MDS)?
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Mobile Database SystemsMobile Database Systems
What is a mobile connectivity?
A mode in which a client or a server can establish
communication with each other whenever needed.
Intermittent connectivity is a special case of mobile
connectivity.
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Mobile Database SystemsMobile Database Systems
A node in which only the client can establishcommunication whenever needed with the server but the
server cannot do so.
What is intermittent connectivity?
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Personal Communication System (PCS)Personal Communication System (PCS)
A system where wired and wireless networks are integrated
for establishing communication.
N: ublic witched Network.
: obile witching enter. Also called
( obile ele hone witching ffice).: ase tation.
: obile tation. Also called U ( obile Unit)
or obile Host ( H).
HLR: Home Location Register.
VLR: Visitor Location Register.
EIR: Equi ment Identify Register.AC: Access Chanel.
N
VLR
HLR
EIR
AC
MSC (MTSO)MSC (MTSO)
MSMS Wireless com onent
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Personal Communication System (PCS)Personal Communication System (PCS)
Wireless Components
BS
MSC (MTSO)
MSMS Wireless component
Base Station (BS) A switch, which serves as
communication link between M and the entire
network
Mobile nits (M ) Also called Mobile Systems (MS) or
Mobile osts (M ). A mobile component, which
communicates with BS through a limited number of
wireless channels.
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Personal Communication System (PCS)Personal Communication System (PCS)
Limited channels must be utilized efficiently. It is done
so by
Fre uency reuse
The same radio fre uency is used for
communication by more than one cell
sessions.
Mobile cells
To achieve fre uency reuse, the entire
wireless coverage area is divided into cells.
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Personal Communication System (PCS)Personal Communication System (PCS)
Problems with cellular structure
How to locate of a mobile unit in the entire
coverage area?
Solution Location management
How to maintain continuous communication
between two parties in the presence of mobility?
Solution oaming
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Personal Communication System (PCS)Personal Communication System (PCS)
Roaming
Roaming is a facility, which allows a subscriber to
enjoy uninterrupted communication from anywhere in
the entire coverage space.
A mobile network coverage space may be managed
by a number of different service providers. They
must cooperate with each other to provide roaming
facility.
Roaming can be provided only if some administrative
and technical constraints are met.
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Personal Communication System (PCS)Personal Communication System (PCS)
Roaming
Administrative constraints
Billing.
Subscription agreement.
Call transfer charges.
ser profile and database sharing.
Any other policy constraints.
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Personal Communication System (PCS)Personal Communication System (PCS)
Roaming
Technical constraints
Bandwidth mismatch. For example, European
900MHz band may not be available in other
parts of the world. This may preclude some
mobile e uipment for roaming.
Service providers must be able to
communicate with each other. eeds some
standard.
Mobile station constraints.
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Personal Communication System (PCS)Personal Communication System (PCS)
Location Management
Two-Tier Scheme
HLR: Home Location Register
A HLR stores user profile and the
geographical location.
LR: VisitorLocation Register
A VLR stores user profile and the current
location who is a visitor to a different cell that
its home cell.
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Personal Communication System (PCS)Personal Communication System (PCS)
Location Management
Two-Tier Scheme steps. M 1 wants to talk to M 2.
M 1
M 2
Cell 1 Cell 2
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Personal Communication System (PCS)Personal Communication System (PCS)
Location Management
Two-Tier Scheme steps. M 1 wants to talk to M 2.
1. VLR of cell 2 is searched for M 2s profile.
2. If it is not found, then HLR is searched.
3. Once the location of M 2 is found, then the
information is sent to the base station of cell 1.
4. Cell 1 establishes the communication.
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Personal Communication System (PCS)Personal Communication System (PCS)
Location Management
Two-Tier Scheme steps location update
1. M 2 moves from cell 1 to cell 2.
2. M 2s location is changed so new location
must be recorded.
3. HLR is updated with the new location address.
4. M 2s entry is deleted from the VLR of cell 1
and new entry is made in cell 2sVLR.
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Mobile Database Systems (MDS)Mobile Database Systems (MDS)
MDS Limitations
Limited wireless bandwidth Wireless communication speed
Limited energy source (battery power)
Less secured
Hard to make theft proof.
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Mobile Database Systems (MDS)Mobile Database Systems (MDS)
MDS Issues
Data Management
Data Caching Data Broadcast (Broadcast disk)
Data Classification
Transaction Management
Query processing
Transaction processing
Concurrency control
Database recovery
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Mobile Database Systems (MDS)Mobile Database Systems (MDS)
MDS Query processing
Query types
Location dependent uery
Location independent uery
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Mobile Database Systems (MDS)Mobile Database Systems (MDS)
MDS Query processing
Location dependent uery
A query whose result depends on the geographical
location of the origin of the query.
Example
What is the distance of Pune railway stationfrom here?
The result of this query is correct only forhere.
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Mobile Database Systems (MDS)Mobile Database Systems (MDS)
MDS Query processing
Location dependent query
Situation: Person traveling in the car desires to
know his progress and continuously asks the
same question. However, every time the answer is
different but correct.
Requirements: Continuous monitoring of the
longitude and latitude of the origin of the query.
GPS can do this.
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Mobile Database Systems (MDS)Mobile Database Systems (MDS)
MDS Transaction Management
Transaction properties: ACID (Atomicity,
Consistency, Isolation, and Durability).
Too rigid for MDS. Flexibility can be introduced
using workflow concept. Thus, a part of the
transaction can be executed and committed
independent to its other parts.
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Mobile Database Systems (MDS)Mobile Database Systems (MDS)
Mobile Agent Technology
A mobile agent is an independent software
module capable of
Migrating to any node on the network
Capable of spawning and eliminating itself
Capable of recording its own history
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Mobile Database Systems (MDS)Mobile Database Systems (MDS)
Conclusions and summary
Wireless network is becoming a commonly used
communication platform. It provides a cheaper wayto get connected and in some cases this is the only
way to reach people. However, it has a number of
easy and difficult problems and they must be solved
before MDS can be built. This tutorial discussed
some of these problems and identified a number of
possible approaches.
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Mobile Database Systems (MDS)Mobile Database Systems (MDS)
Conclusions and summary
The emerging trend is to make all service providing
disciplines, such as web, E-commerce, workflowsystems, etc., fully mobile so that any service can
be provided from any place. Customer can surf the
information space from any location at any time and
do their shopping, make flight reservation, open
bank account, attend lectures, and so on. This is
what the wireless technology driving us to.
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THANK YOU