Cellular digital packet data
Encyclopedia
Cellular Digital Packet Data (CDPD) was a wide-area mobile data service which used unused bandwidth
normally used by AMPS
mobile phone
s between 800 and 900 MHz to transfer data. Speeds up to 19.2 kbit/s were possible. The service was discontinued in conjunction with the retirement of the parent AMPS service; it has been functionally replaced by faster services such as 1xRTT, EV-DO, and UMTS/HSPA
.
Developed in the early 1990s, CDPD was large on the horizon as a future technology. However, it had difficulty competing against existing slower but less expensive Mobitex
and DataTac
systems, and never quite gained widespread acceptance before newer, faster standards such as GPRS became dominant.
CDPD had very limited consumer offerings. AT&T Wireless
first offered the technology in the United States under the PocketNet brand. It was one of the first consumer offerings of wireless web service. A company named OmniSky provided service for Palm V devices. Cingular Wireless later offered CDPD under the Wireless Internet brand (not to be confused with Wireless Internet Express, their brand for GPRS/EDGE data). PocketNet was generally considered a failure with competition from 2G services such as Sprint's Wireless Web. After the four phones AT&T Wireless had offered to the public (two from Panasonic, one from Mitsubishi and the Ericsson R289LX), AT&T Wireless eventually refused to activate the devices.
Despite its limited success as a consumer offering, CDPD was adopted in a number of enterprise and government networks. It was particularly popular as a first-generation wireless data solution for telemetry
devices (machine to machine communications) and for public safety mobile data terminals.
In 2004, major carriers in the United States
announced plans to shut down CDPD service. In July 2005, the AT&T Wireless
and Cingular Wireless
CDPD networks were shut down. Equipment for this service now has little to no residual value.
1. End systems: physical & logical end systems that exchange information
2. Intermediate systems: CDPD infrastructure elements that store, forward & route the information
There are 2 kinds of End systems
1. Mobile end system: subscriber unit to access CDPD network over a wireless interface
2. Fixed end system: common host/server that is connected to the CDPD backbone and providing access to specific application and data
There are 2 kinds of Intermediate systems
1. Generic intermediate system: simple router with no knowledge of mobility issues
2. mobile data intermediate system: specialized intermediate systemthat routes data based on its knowledge of the current location of Mobile end system. It is a set of hardware and software functions that provide switching, accounting, registration, authentication, encryption, and so on.
Bandwidth (computing)
In computer networking and computer science, bandwidth, network bandwidth, data bandwidth, or digital bandwidth is a measure of available or consumed data communication resources expressed in bits/second or multiples of it .Note that in textbooks on wireless communications, modem data transmission,...
normally used by AMPS
Advanced Mobile Phone System
Advanced Mobile Phone System was an analog mobile phone system standard developed by Bell Labs, and officially introduced in the Americas in 1983, Israel in 1986, and Australia in 1987. It was the primary analog mobile phone system in North America through the 1980s and into the 2000s...
mobile phone
Mobile phone
A mobile phone is a device which can make and receive telephone calls over a radio link whilst moving around a wide geographic area. It does so by connecting to a cellular network provided by a mobile network operator...
s between 800 and 900 MHz to transfer data. Speeds up to 19.2 kbit/s were possible. The service was discontinued in conjunction with the retirement of the parent AMPS service; it has been functionally replaced by faster services such as 1xRTT, EV-DO, and UMTS/HSPA
High Speed Packet Access
High Speed Packet Access is an amalgamation of two mobile telephony protocols, High Speed Downlink Packet Access and High Speed Uplink Packet Access , that extends and improves the performance of existing WCDMA protocols...
.
Developed in the early 1990s, CDPD was large on the horizon as a future technology. However, it had difficulty competing against existing slower but less expensive Mobitex
Mobitex
Mobitex is an OSI based open standard, national public access wireless packet-switched data network. Mobitex puts great emphasis on safety and reliability with its use by military, police, firefighters and ambulance services. Mobitex was developed in the beginning of the 1980s by the Swedish...
and DataTac
DataTAC
DataTAC is a wireless data network technology originally developed by Motorola and deployed in the United States as the ARDIS network. DataTAC was also marketed in the mid-1990s as MobileData by Telecom Australia, and is still used by Bell Mobility as a paging network in Canada...
systems, and never quite gained widespread acceptance before newer, faster standards such as GPRS became dominant.
CDPD had very limited consumer offerings. AT&T Wireless
AT&T Wireless
AT&T Wireless Services, Inc., founded in 1987 as McCaw Cellular Communications, Inc., and now legally known as New Cingular Wireless Services, Inc., formerly part of AT&T Corp., is a wireless telephone carrier in the United States, based in Redmond, Washington, and later traded on the New York...
first offered the technology in the United States under the PocketNet brand. It was one of the first consumer offerings of wireless web service. A company named OmniSky provided service for Palm V devices. Cingular Wireless later offered CDPD under the Wireless Internet brand (not to be confused with Wireless Internet Express, their brand for GPRS/EDGE data). PocketNet was generally considered a failure with competition from 2G services such as Sprint's Wireless Web. After the four phones AT&T Wireless had offered to the public (two from Panasonic, one from Mitsubishi and the Ericsson R289LX), AT&T Wireless eventually refused to activate the devices.
Despite its limited success as a consumer offering, CDPD was adopted in a number of enterprise and government networks. It was particularly popular as a first-generation wireless data solution for telemetry
Telemetry
Telemetry is a technology that allows measurements to be made at a distance, usually via radio wave transmission and reception of the information. The word is derived from Greek roots: tele = remote, and metron = measure...
devices (machine to machine communications) and for public safety mobile data terminals.
In 2004, major carriers in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
announced plans to shut down CDPD service. In July 2005, the AT&T Wireless
AT&T Wireless
AT&T Wireless Services, Inc., founded in 1987 as McCaw Cellular Communications, Inc., and now legally known as New Cingular Wireless Services, Inc., formerly part of AT&T Corp., is a wireless telephone carrier in the United States, based in Redmond, Washington, and later traded on the New York...
and Cingular Wireless
Cingular Wireless
AT&T Mobility LLC is a wholly owned subsidiary of AT&T that provides wireless services to 100.7 million subscribers in the United States, Puerto Rico and the U.S. Virgin Islands...
CDPD networks were shut down. Equipment for this service now has little to no residual value.
CDPD Network
Primary elements of a CDPD network are:1. End systems: physical & logical end systems that exchange information
2. Intermediate systems: CDPD infrastructure elements that store, forward & route the information
There are 2 kinds of End systems
1. Mobile end system: subscriber unit to access CDPD network over a wireless interface
2. Fixed end system: common host/server that is connected to the CDPD backbone and providing access to specific application and data
There are 2 kinds of Intermediate systems
1. Generic intermediate system: simple router with no knowledge of mobility issues
2. mobile data intermediate system: specialized intermediate systemthat routes data based on its knowledge of the current location of Mobile end system. It is a set of hardware and software functions that provide switching, accounting, registration, authentication, encryption, and so on.