Integrated Digital Enhanced Network

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For other uses of Iden/IDEN see Iden (disambiguation)

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).

[edit] 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 separately transmit and receive signals, with transmit and receive bands separated by 39MHz, 45MHz, or 48MHz 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, since time-division duplexing of RF section usage can be performed.

[edit] Hardware

The first ever iDEN handset was Motorola's L3000, which was released in 1994. 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. 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. 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).

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'.

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 pulse.

[edit] 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.

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. The speed of iDEN's Push-To-Talk (a.k.a Dispatch) feature is unparalleled, and remains the fastest in the industry as compared to Qchat and Verizon PTT in the US. iDEN is a 2G system whereas Qchat and Verizon PTT require 3G systems.

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. With the introduction of Small System Release 6.1, it gains the ability to interface with a full iDEN system. SSR7.0 is the latest Harmony Small System Release.

[edit] Countries operating iDEN networks

Company Name	Country	Push To Talk Name
Airtel Wireless Ltd.	Alberta, Canada	Fleet Connect
Airpeak	United States	Talk Direct
Airtel	United States	cellular radio
ARINC	United States
Avantel	Colombia
Boost Mobile	United States	Chirp
Bravo Telecom	Saudi Arabia	Push To Talk
Procall Pvt. Ltd.	India	Digital Push To Talk
China Satcom Guomai Comm Co. L	China
Connect Net	United States
GRID Communications	Singapore	Push To Talk
Iconnect	Guam	iConnect PTT
Intelfon	El Salvador	RED
Intelfon	Guatemala	RED
Mirs	Israel
Monttcashire	Ecuador
NEXNET	Japan
Sprint	United States	Direct Connect
Nextel Argentina	Argentina	Direct Connect
Nextel Brazil	Brazil	Direct Connect
Nextel Chile	Chile	Direct Connect
Nextel Mexico	Mexico	Direct Connect
Nextel Peru	Peru	Direct Connect
Next Mobile	Philippines	Walkie-Talkie
Proxtel Wireless	Puerto Rico
Shenzhen Yunliantong Comm Service	China
KT Powertel	South Korea
SouthernLINC Wireless	United States	InstantLINC
Telus	Canada	Mike
Inquam Telecom	Morocco
XPress	Jordan	XPress Direct Connect