CDPD: Cellular Digital Packet Data

1
CDPDCellular Digital Packet Data
2
What Is CDPD

• A service?
• A technology?
• A network?
• A standard?

3
Introduction

• In 1993, the first version of standard of CDPD
  came into view.
• In 1994, in America, the first CDPD experimental
  network run.
• CDPD offer one of the most advanced means of
  wireless data transmission technology.
• CDPD transmits digital packet data at 19.2 Kbps.
• CDPD system allow user to transmit data with a
  higher degree of accuracy, strong security, and
  few service interruption

4
CDPD Definition

• CDPD is a technique for quick transfer of data.
• It transmitts data at 19.2 kbps.
• It transmitt the packet over the cellular network
  in a reliable manner.
• In 1993, the first version of standard of CDPD
  came into view.
• In 1994, in America, the first CDPD experimental
  network run.

5
Key CDPD Characteristics

• Availability Identifies whether CDPD services
  can be acquired from a carrier in a given region
• Coverage Identifies whether CDPD transmission
  can reach users in a given region.
• Reliability Identifies whether user can access
  and use CDPD services during congestion or
  network disruption
• Transmission Speed Describe the end to end data
  speed, including call setup time transmission
  speed

6
Key CDPD Characteristics

• 5. Privacy and Security Describe the level of
  inherent privacy and security of the service and
  the capability to add security measure
• 6. Cost Characterizes the cost typical of
  CDPD service.

7
Features

1. Same Coverage as cellular system
2. Schedule data packets to unused voice channel
3. 19.2 Kbps raw data transfer rate.
4. Full duplex transreciever
5. 600 mw transmit power
6. Integrated TCP/IP protocol stack
7. Compact size
8. Strong aluminum case
9. LEDs show status of CDPD operation

8
Working Of CDPD

• It uses Channel Hopping Technique.
• Initiates data transmission
• Location Of available channel to establish data
  link.
• Mobile data unit transmit data packets.
• CDPD technology transmits chunks or packets of
  data
• Equipment 1) CDPD Modem 2) User terminal

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User Equipment

• 1 .CDPD Modem
• It Includes wireless antenna and modem that
  provides compatibility with network.
• It can be internal or external.
• 2 .User Terminal
• Any device that supports IP-based data
  communication can use CDPD .
• Examples are as notebook or laptop Personal
  Computers (PCs), handheld computers or PCs.

10
Interfaces

• A Interface Air interface
• I Interface Intermediate system interface
• E Interface External interface

11
Components

• 1. Mobile End System ( M-ES)
• Mobile computing device which has a cdpd modem
  built-in or attached
• It support mac functionality
• It transmit data over the airlink to MDBS
• It should provide transparent interface to the
  user application
• Example is CDPD modem

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Components

• 2. Mobile data base station (MDBS)
• It located at the cell site.
• It is responsible for R.F management
• It provide hop to hop control over the air
  interface
• It controls the hop RF segment between the M-ES
  and the cdpd network
• Cellular geographic area control by MDBS

13
Components

• 3. Mobile Data Intermediate System(MDIS)
• MDIS routs data packet to and from the CDPD N.W
  the M-ES appropriately
• It validates M-ES using encryption keys for
  secure transmission of data
• It is responsible for IP routing
• An MDIS may serve single or multiple CGSA cells
• It can provides mobile home serving functions

14
Components

• 4. INTERMEDIATE SYSTEM (IS)
• It is the standard IP router
• It routes the data through IP CLNP, N.W
• The IS components are the backbone of CDPD mesh

15
Components

• 5. FIXED END SYSTEM (F- ES)
• F-ES is the final destination of message sent
  from M-ES
• F-ES received the data process it appropriately
• The F-Es can be one of many stationary computing
  devices such as host computer , UNIX workstation

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CDPD - Layering
IP/CLNP
Connectionless Network Protocol Subnetwork
Dependant Convergence Protocol Mobile Data Link
Protocol Media Access Control Physical
SNDCP
MDLP
MAC
Physical
Network layer CDPD Layer
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Mobile Data Link Protocol

• It provides logical link control services between
  Mobile End Systems and Mobile Data Intermediate
  Systems.
• The purpose of MDLP is to transmit information
  between network layer entities across the CDPD
  Air link interface.
• High-level data link control (HDLC)
• Temporary equipment identifier (TEI)
• Identifies destination mobile - virtual address.

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Subnetwork Dependent Convergence Protocol

• Encryption/decryption
• User data confidentiality
• SNDCP provides a number of services to the
  network layer
• Compression/elimination of redundant protocol
  control information

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Mobile Network Registration Protocol

• Exchange of routing and registration information
  between the M-ES and a serving MD-IS.
• Delivery of authentication information about an
  M-ES.
• Registration and Authentication of multicast NEI.
  

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Radio Resource Management

• It prevents interference of radio channel and
  other wireless communication characteristic.
• RRM concerns multi-user and multi-cell network
  capacity issues, rather than point-to-point
  channel capacity .
• The objective of radio resource management is to
  maximize the system spectral efficiency in
  bit/s/Hz/base station site or Erlang/MHz/site.

21
Application of CDPD

• Credit card verification
• ATM network
• Transportation Ambulance, dispatch system.
• Public security Policemen can access the latest
  database in real time to. E.g. Check suspected
  person, Verify identity. Check the car current
  status.
• Remote measurement Remote control.
• Commerce. Wireless ATM. Wireless Credits Card
  Authentication. Mobile Payment.

22
Application of CDPD

• Implementing easily.
• High speed. CDPD modem set up time is much faster
  than wire dial up modem. Even CDPD is 19.2kbps,
  wire dial up modem is 33.6kbps.
• Reliable and Safety with strong encryption
  algorithm.
• Personal use which covers the main part of the
  CDPD usage.

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Wireless ATM Via CDPD

• More and more popular in China.
• Very convenient.
• CDPD provides reliable, fast and safe access.
• Maintenance is not very high.

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References

• http//en.wikipedia.org/wiki/Radio_resource_manage
  ment
• http//www.protocols.com/pbook/cdpd.htm
• http//www.amycsizmardalal.com/research/CDPD/intro
  .html
• http//www.webtechniques.com/archives/2001/11/jeps
  on/
• http//en.wikipedia.org/wiki/Fleet_management
• http//www.buzzle.com/editorials/8-29-2004-58574.a
  sp

• http//en.wikipedia.org/wiki/Radio_resource_manage
  ment
• http//www.protocols.com/pbook/cdpd.htm
• http//www.amycsizmardalal.com/research/CDPD/intro
  .html
• http//www.webtechniques.com/archives/2001/11/jeps
  on/
• http//en.wikipedia.org/wiki/Fleet_management
• http//www.buzzle.com/editorials/8-29-2004-58574.a
  sp