CDPD:CDPD:Cellular Digital Packet DataCellular Digital Packet Data

What Is What Is CDPDCDPD

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

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

CDPD DefinitionCDPD 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.

Key CDPD CharacteristicsKey CDPD Characteristics

1. Availability: Identifies whether CDPD services can be acquired from a carrier in a given region

2. Coverage: Identifies whether CDPD transmission can reach users in a given region.

3. Reliability: Identifies whether user can access and use CDPD services during congestion or network disruption

4. Transmission Speed: Describe the end to end data speed, including call setup time & transmission speed

Key CDPD CharacteristicsKey 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.

Features

1. Same Coverage as cellular system2. Schedule data packets to unused voice channel3. 19.2 Kbps raw data transfer rate.4. Full duplex transreciever5. 600 mw transmit power6. Integrated TCP/IP protocol stack7. Compact size8. Strong aluminum case9. LED’s show status of CDPD operation

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

UserUser EquipmentEquipment

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.

InterfacesInterfaces

• A Interface : Air interface

• I Interface : Intermediate system interface

• E Interface : External interface

ComponentsComponents

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

ComponentsComponents

2. Mobile data base station (MDBS)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

ComponentsComponents 3. Mobile Data Intermediate System(MDIS)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

ComponentsComponents

4. INTERMEDIATE SYSTEM (IS)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

ComponentsComponents

5. FIXED END SYSTEM (F- ES)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

CDPD - LayeringCDPD - Layering

Physical

MAC

MDLP

SNDCP

IP/CLNPIP/CLNP

PhysicalPhysical

Data linkData link

NetworkNetwork

TransportTransport

ApplicationApplication

Network layer CDPD LayerNetwork layer CDPD Layer

Connectionless Network Protocol

Subnetwork Dependant Convergence Protocol

Mobile Data Link Protocol

Media Access Control

Physical

Mobile Data Link ProtocolMobile 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.

Subnetwork Dependent Convergence ProtocolSubnetwork 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

Mobile Network Registration ProtocolMobile 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.

Radio Resource ManagementRadio 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.

Application of CDPDApplication 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.

Application of CDPDApplication 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.

Wireless ATM Via CDPD

• More and more popular in China.

• Very convenient.

• CDPD provides reliable, fast and safe access.

• Maintenance is not very high.

ReferencesReferences

• http://en.wikipedia.org/wiki/Radio_resource_management

• http://www.protocols.com/pbook/cdpd.htm• http://

www.amycsizmardalal.com/research/CDPD/intro.html

• http://www.webtechniques.com/archives/2001/11/jepson/

• http://en.wikipedia.org/wiki/Fleet_management• http://www.buzzle.com/editorials/8-29-2004-

58574.asp

• http://en.wikipedia.org/wiki/Radio_resource_management

• http://www.protocols.com/pbook/cdpd.htm• http://www.amycsizmardalal.com/research/

CDPD/intro.html• http://www.webtechniques.com/archives/

2001/11/jepson/• http://en.wikipedia.org/wiki/Fleet_management• http://www.buzzle.com/editorials/8-29-2004-

58574.asp