Integrated Digital Enhanced Network

Integrated Digital Enhanced Network

Integrated Digital Enhanced Network (iDEN) is a mobile telecommunications technology, developed by Motorola, which provides its users the benefits of a trunked radio and a cellular telephone. iDEN places more users in a given spectral space, compared to analog cellular and two-way radio systems, by using speech compression and time division multiple access (TDMA).

Contents

Operating frequencies

iDEN is designed and licensed to operate on individual frequencies that may not be contiguous. iDEN operates on 25 kHz channels, but only occupies 20 kHz in order to provide interference protection via guard bands. By comparison, TDMA Cellular (Digital AMPS) is licensed in blocks of 30 kHz channels, but each emission occupies 40 kHz, and is capable of serving the same number of subscribers per channel as iDEN. iDEN uses frequency-division duplexing to transmit and receive signals separately, with transmit and receive bands separated by 39 MHz, 45 MHz, or 48 MHz depending on the frequency band being used.[1]

iDEN supports either three or six interconnect users (phone users) per channel, and six dispatch users (push-to-talk users) per channel, using time division multiple access. The transmit and receive time slots assigned to each user are deliberately offset in time so that a single user never needs to transmit and receive at the same time. This eliminates the need for a duplexer at the mobile end, since time-division duplexing of RF section usage can be performed.

Hardware

The first commercial iDEN handset was Motorola's L3000, which was released in 1994[citation needed]. Most modern iDEN handsets use SIM cards, similar to, but incompatible with GSM handsets' SIM cards. Early iDEN models such as the i1000plus stored all subscriber information inside the handset itself, requiring the data to be downloaded and transferred should the subscriber want to switch handsets. Newer handsets using SIM technology make upgrading or changing handsets as easy as swapping the SIM card. Four different sized SIM cards exist, "Endeavor" SIMs are used only with the i2000 without data, "Condor" SIMs are used with the two-digit models (i95cl, for example) using a SIM with less memory than the three-digit models (i730, i860), "Falcon" SIMs are used in the three-digit phones, (i530, i710) and will read the smaller SIM for backward compatibility, but some advanced features such as extra contact information is not supported by the older SIM cards[citation needed]. There is also the "Falcon 128" SIM, which is the same as the original "Falcon", but doubled in memory size, which is used on new 3 digit phones (i560, i930)[citation needed].

iDEN base radio at a cell site

The interconnect-side of the iDEN network uses GSM signalling for call set-up and mobility management, with the Abis protocol stack modified to support iDEN's additional features. Motorola has named this modified stack 'Mobis'[citation needed].

Each base site requires precise timing and location information to synchronize data across the network. To obtain and maintain this information each EBTS uses GPS satellites to receive a precise timing reference[citation needed].

Operators

In the United States of America there are two large public iDEN service providers: Sprint Nextel and SouthernLINC Wireless, and several small public and private iDEN service providers. Numerous private systems exist, including one run by ARINC, covering all major airports. Countries which have operating iDEN networks include Canada, Argentina, Peru, Mexico, Brazil, Jordan, Chile, Israel, Philippines, Singapore, Saudi Arabia, Japan, El Salvador, China and most recently India and Guatemala. Full Roaming is available between Sprint/Nextel in the US, Telus (Canada), and NII (Mexico and S. American markets) Data/Voice/Radio. For markets not controlled by NII Holdings, Inc., the roaming is for voice telephony only[citation needed].

Motorola is committed to support of iDEN technology despite the Sprint buyout of Nextel and Sprint/Nextel's supposed eventual conversion to Sprint's CDMA system. Nextel has stated they will support iDEN until at least 2010 and Sprint has recently released new iDEN handsets and maintained their iDEN holdings with the purchase of the Sprint CDMA affiliate network, iPCS, for $426 million, which Sprint was repeatedly engaged in lawsuits with over non-compete agreement violations stemming from the 2005 purchase of Nextel and the later purchase of Nextel Partners. Other iDEN carriers have no foreseeable expiration date for their services[citation needed]. The speed of iDEN's push-to-talk (a.k.a dispatch) feature remains the fastest in the industry as compared to Sprint Qchat [Qualcomm PTT over EVDO Rev. A] and Verizon PTT [requiring at least 1XRTT data] in the US[citation needed].

There is a smaller subset of the iDEN network called "Harmony Wireless Communications System". With Small System Release 7.0, it supports a maximum site count of 160 or 576 individual cells. Harmony has the ability to interface with a full iDEN system, and has the ability to support interconnect, dispatch, and packet data. SSR7.1 is the latest Harmony release[original research?].

Countries operating iDEN networks

Company Name Country Push To Talk Name
Airtel Wireless Ltd. Canada Calgary, Alberta, Ca Churp
Fleetcom Inc. Canada Toronto, Ontario, Ca Push-to-Talk
Airpeak United States United States Talk Direct
ARINC United States United States
Avantel Colombia Colombia Comunicación Inmediata
Boost Mobile United States United States Chirp
Bravo Telecom Saudi Arabia Saudi Arabia Push To Talk
Procall Pvt. Ltd. India India Digital Push To Talk
China Satcom Guomai Comm Co. L China China
Iconnect China China Hong Kong(SAR)
Connect Net United States United States
GRID Communications Singapore Singapore Push To Talk
Iconnect Guam Guam iConnect PTT
Intelfon El Salvador El Salvador RED
Intelfon Guatemala Guatemala RED
Mirs Israel Israel Walkie-Talkie
Monttcashire Ecuador Ecuador
NEXNET Japan Japan
Spacedata United States United States
Sprint Nextel United States United States Direct Connect
Nextel Argentina Argentina Argentina Direct Connect
Nextel Brazil Brazil Brazil Direct Connect
Nextel Chile Chile Chile Direct Connect
Nextel Mexico Mexico Mexico Conexión Directa
Nextel Peru Peru Peru Direct Connect
Vona Brazil Brazil Radio Despacho
Next Mobile Philippines Philippines Walkie-Talkie
Proxtel Wireless Puerto Rico Puerto Rico Direct Connect
Shenzhen Yunliantong Comm Service China China
KT Powertel South Korea South Korea
SouthernLINC Wireless United States United States InstantLINC
Telus Canada Canada Mike
Inquam Telecom Morocco Morocco
XPress Jordan Jordan XPress Direct Connect

See also

References

  1. ^ Motorola iDEN Technical Overview

External links


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