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 25kHz 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 technolgies duplex their handsets. Also, like other digital-only technologies, hybrid or cavity duplexing is used at the Base Station (Cellsite).
More Than a Wireless Phone
iDEN technology offers you more than just a wireless phone. It's a Motorola complete communications system that you hold in your hand. Combining speakerphone, voice command, phone book, voice mail, digital two-way radio, mobile Internet and e-mail, wireless modems, voice activation, and voice recordings so that you can virtually recreate your office on the road
TDMA (Time Division Multiple Access):
iDEN's digital technology divides a channel into different "slots". Each slot can carry one voice or data transmission. By deploying an iDEN system, service providers can increase capacity by as much as six times their current analog Specialized Mobile Radio (SMR) network.
This capacity increase is accomplished using a state-of-the-art technology called TDMA. TDMA utilizes Global Positioning Satellites (GPS) to reference a synchronized time, and then divides the channel into time slots. As a result, channel capacity is increased because one channel has now been converted to multiple voice or data transmission vehicles. TDMA is a proven technology in cellular systems across Europe, the US, and in Japan. iDEN utilizes TDMA for Maximum Spectrum Efficiency.
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