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CDPD: Cellular Digital Packet Data. What Is CDPD. 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.
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What Is CDPD • 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 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 Characteristics • Availability: Identifies whether CDPD services can be acquired from a carrier in a given region • Coverage: Identifies whether CDPDtransmission 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
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.
Features • Same Coverage as cellular system • Schedule data packets to unused voice channel • 19.2 Kbps raw data transfer rate. • Full duplex transreciever • 600 mw transmit power • Integrated TCP/IP protocol stack • Compact size • Strong aluminum case • 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
UserEquipment 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.
Interfaces • A Interface : Air interface • I Interface : Intermediate system interface • E Interface : External interface
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
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
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
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
Components 5. FIXED END SYSTEM (F- ES) • F-ES is the finaldestinationof 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
Application Transport Network Data link Physical 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
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.
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
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.
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 istomaximize the system spectral efficiency in bit/s/Hz/base station site or Erlang/MHz/site.
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.
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.
Wireless ATM Via CDPD • More and more popular in China. • Very convenient. • CDPD provides reliable, fast and safe access. • Maintenance is not very high.
References • 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