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Integrated Digital Enhanced Network

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Mobile phone and data
standards

0.5G

GSM
iDEN
D-AMPS
IS-95/cdmaOne
PDC
CSD
PHS

2.5G

2.75G

CDMA2000 1xRTT/IS-2000
EDGE (EGPRS)

W-CDMA
- UMTS (3GSM)
- FOMA
TD-CDMA/UMTS-TDD
1xEV-DO/IS-856
TD-SCDMA
GAN/UMA

3.5G

HSDPA

3.75G

Frequency bands

Iden is also a village in East Sussex, England

Image:Iden.JPG

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. Notably, 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 (IS-54 and IS-136) 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 supports either three or six interconnect users (phone users) per channel, and either six or twelve dispatch users (push-to-talk users) per channel. Since there is no Analogue component of iDEN, mechanical duplexing in the handset is unnecessary, so Time Domain Duplexing is used instead, the same way that other digital-only technologies duplex their handsets. Also, like other digital-only technologies, hybrid or cavity duplexing is used at the Base Station (Cellsite).

Most modern iDEN handsets use SIM cards, just like GSM and compatible with GSM handsets. 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. Two different sized SIM cards exist, with the two-digit models (i95cl, for example) using a SIM with less memory than the three-digit models (i730, i860). The three-digit phones will read the smaller SIM for backward compatibility, but some advanced features such as extra contact information and possibly GPS reception is disabled.

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'. All things being equal, iDEN is an excellent technology, and if Motorola and Nextel had not kept iDEN proprietary, it would have been a contender for one of the most spectrum efficient and feature unique world-standards, at least until the introduction of UMTS. Even now that GSM has finally adopted a push-to-talk standard, iDEN is still the best performer in regard to latency. It also out-performs Qualcomm's Q-chat, for CDMA (IS-95), as far as latency is concerned.

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 (the service provider is Telus), Mexico, Brazil, Jordan, Israel, Philippines, Singapore, South Korea, Saudi Arabia, Japan, El Salvador and China. Full Roaming is available between Sprint/Nextel in the US, Telus (Canada), and NII (Mexico and S. American markets) Data/Voice/Radio. Voice only roaming in non NII markets Israel, Jordan, South Korea, Singapore, Philippines and Guam.

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, while other iDEN carriers have no foreseeable expiration date for their services. iDEN's Push-To-Talk feature is the fastest in the industry.

There is a smaller subset of the iDEN network called "Harmony Wireless Communications System", With Small System Release 5.0, it supports a maximum limit of 192 sites.