Iden n244r

iDEN

Introduction iDEN is a mobile telecommunications technology, developed by Motorola, which provides its s the benefits of a trunked radio and a cellular telephone. iDEN places more s 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 (IS54 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 s either three or six interconnect s (phone s) per channel, and either six or twelve dispatch s (push-to-talk s) 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).

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History First introduced in 1994, Motorola's Integrated Digital Enhanced Network (iDEN™) brought to the market next generation wireless solutions designed for a variety of vertical market mobile business applications. Today, iDEN wireless handsets are utilized in a variety of work environments ranging from manufacturing floors to executive conference rooms as well as mobile sales forces. Motorola iDEN handset s are finding new applications and discovering unique communication solutions every day to help their businesses evolve and grow. For example, Motorola's iDEN solution offers the ability for you to hold a conference with a large number of people, with only the push of a button, helping you eliminate time-wasting and costly individual calls.

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Streamlining Communications into One Digital Handset Four-in-one iDEN technology allows business s to take advantage of advanced wireless technologies with one pocket-sized digital handset that combines: two-way digital radio; digital wireless phone; alphanumeric messaging; and data/fax capabilities leveraging Internet technology.iDEN technology allows you the freedom to go anywhere while still keeping track of what's important to not only your business but your personal life as well. Motorola's iDEN solution truly simplifies your life by streamlining all of your communications tools.

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.

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Cutting-Edge System of Technologies iDEN technology is a highly innovative, cutting-edge system of technologies developed by Motorola to create an ideal, complete wireless communications system for today's fast-paced, busy lifestyle. Advanced capabilities bring together the features of dispatch radio, full-duplex telephone interconnect, short messaging service and data transmission

Key Technologies 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.

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TDMA is a proven technology in cellular systems across Europe, the US, and in Japan. iDEN utilizes TDMA for Maximum Spectrum Efficiency. Time division multiple access (TDMA) is a channel access method for shared medium networks. It allows several s to share the same frequency channel by dividing the signal into different timeslots. The s transmit in rapid succession, one after the other, each using his own timeslot. This allows multiple stations to share the same transmission medium . While using only the part of its bandwidth they require. TDMA is used in the digital 2G cellular systems such as Global System for Mobile Communications(GSM), IS-136, Personal Digital Cellular(PDC) and iDEN, and in the Digital Enhanced Cordless Telecommunications (DECT) standard for portable phones. It is also used extensively in satellite systems, and combat-net radio systems. For usage of Dynamic TDMA packet mode communication, see below.

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VSELP (Vector Sum Excited Linear Prediction): VSELP digitally codes and significantly compresses voice signals, increasingradio channel capacity by reducing the amount of information that needs to be transmitted. VSELP provides iDEN systems with the capability to fit voice transmission into the smaller transmissions vehicle that results from TDMA. Vector Sum Excited Linear Prediction, or VSELP, is a speech coding method used in the IS-54 standard. This codec was used in early TDMA cell phones in the United States. It was also used in the first version of RealAudio for audio over the Internet. The IS-54 VSELP standard was published by the Telecommunications Industry Association in 1989. IS-54 VSELP specifies an encoding of each 20 ms of speech into 159-bit frames, thus achieving a raw data rate of 7.95 kbit/s. In an actual TDMA cell phone, the vocoder output is packaged with error correction and signaling information, resulting in an overthe-air data rate of 16.2 kbit/s. For internet audio, each 159-bit frame is stored in 20 bytes, leaving 1 bit unused. The resulting file thus has a data rate of exactly 8 kbit/s. A major drawback of VSELP is its limited ability to encode non-speech sounds, so that it performs poorly when encoding speech in the presence of background noise. For this reason, use of VSELP has been gradually phased out in favor of newer codecs.

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QAM (Quad Amplitude Modulation): Quad Amplitude Modulation results in 64 kbps data rate over a 25 kHz channel. Quadrature amplitude modulation (QAM) is a modulation scheme which conveys data by changing (modulating) the amplitude of two carrier waves. These two waves, usually sinusoids, are out of phase with each other by 90° and are thus called quadrature carriers , hence the name of the scheme.

QAM Transmitter The following picture shows the ideal structure of a QAM transmitter, with a carrier frequency f0 and Ht the frequency response of the transmitter's filter:

First the flow of bits to be transmitted is split into two equal parts: this process

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generates two independent signals to be transmitted. They are encoded separately just like they were in an amplitude-shift keying (ASK) modulator. Then one channel (the one "in phase") is multiplied by a cosine, while the other channel ("in quadrature") is multiplied by a sine. This way there is a phase of 90° between them. They are simply added one to the other and sent through the real channel

QAM Receiver The receiver simply performs the inverse process of the transmitter. Its ideal structure is shown in the picture below with Hr the receive filter's frequency response:

Multiplying by a cosine (or a sine) and by a low- filter it is possible to extract the component in phase (or in quadrature). Then there is only an ASK demodulator and the

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two flows of data are merged back.In any application, the low- filter will be within hr (t): here it was shown just to be clearer.

iDEN Mobile Operations Some of the iDEN mobile operations are: Control Channel Acquisition When first powered up, an iDEN mobile radio scans selected iDEN frequencies and locks on to the designated control channel. The control channel carries information ontinuously broadcast by the fixed end system regarding system identification and timing parameters for the mobile radio to use when it operates on the system. The control channel also defines the maximum transmit power that radios on the system may use.

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Mobile Synchronization In its operational mode, the mobile radio aligns its frequency and transmit timing to the outbound signal received from the fixed end system. Mobile Registration Each mobile radio in an iDEN system is identified by an international mobile station identifier (IMSI), which is assigned to it when it is first placed in service and performs an initial registration with the fixed end system. When making its registration request, the mobile radio supplies its international mobile equipment identifier (IMEI) to the fixed end system. After determining the validity of the IMEI, the fixed end station assigns an IMSI to the subscriber radio. International Mobile Subscriber Identity (IMSI) An International Mobile Subscriber Identity, or IMSI is a unique number that is ssociated with all GSM and Universal Mobile Telecommunications System (UMTS) network mobile phone s. The number is stored in the Subscriber Identity Module (SIM). It is sent by the mobile phone to the network and is also used to acquire other details of the mobile in the Home Location (HLR) or as locally copied in the Visitor Location . In order to avoid the subscriber being identified and tracked by

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eavesdroppers on the radio interface, the IMSI is sent as rarely as possible and a randomly generated TMSI is sent instead. Also the IMSI is used in ANY mobile network that interconnect with others. We are talking here about CDMA and EVDO networks and this number is provisioned in the phone directly or in the RUIMS card (a CDMA analogue to SIM card in GSM) An IMSI is usually fifteen digits long. However, they can be shorter (eg. MTN South Africa's are 14 digits). The first three digits are the country code (mobile country code), and the next digits are the Mobile Network Code (MNC). The MNC can be either two digits long (normal e.g. in Europe) or three digits long (normal in North America), the remaining digits, up to the maximum length are the unique subscriber number (MSIN) within the network's customer base.

International Mobile Equipment Identity (IMEI) The International Mobile Equipment Identity (IMEI) is a number unique to every GSM and UMTS mobile phone. It is usually found printed on the phone underneath the battery and can also be found by dialling the sequence *#06# into the phone. The IMEI number is used by the GSM network to identify valid devices and therefore itcan be used to stop a stolen phone from accessing the network. For example, if a mobile 11

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phone is stolen, the owner can call his or her network provider and instruct them to "ban" the phone using its IMEI number. This renders the phone useless, regardless of whether the phone's SIM is changed. Unlike the Electronic Serial Number or MEID of CDMA and other wireless networks, the IMEI is only used to identify the device, and has no permanent or semi-permanent relation to the subscriber. Instead, the subscriber is identified by transmission of an IMSI number, which is stored on a SIM card which can (in theory) be transferred to any handset. However, many network and security features are enabled by knowing the current device being used by a subscriber.

Mobile Assisted Handovers When operating in a moving vehicle, an iDEN mobile radio can assist the fixed end system in determining when a handover to another cell should be executed. Whenever the mobile radio is not actually transmitting or receiving a signal from the fixed end system, it monitors outbound signals from neighboring cells and measures the received power and signal quality of these signals. When it determines that the signal from a neighboring cell is of higher quality than the signal from the fixed end system in its currently assigned cell, it transmits a handover request to the fixed end system. The iDEN infrastructure can also query a mobile radio for a measurement report. The mobile radio then transmits data

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back to the fixed end system indicating the received signal strength detected and measured by the mobile radio. iDEN in Push-to-talk Service iDEN is the only commercial technology that offers push-to-talk( PTT) service. What is push-to-talk? Push-to-talk enables a mobile telephone to act like a walkie-talkie by connecting s with the push of a button. The goal of push-to-talk is to instantaneously connect important s without one person’s having to place a traditional telephone call and wait for the other party to “pick up” or answer. In addition, push-to-talk can offer features such as calling groups so that more than two s can communicate at the same time. Like a walkie talkie, this communication is half-duplex; therefore, s must press and hold the button while they speak, and only one person can speak at a time (hence the name push-to-talk). This service is also commonly referred to as PTT, P2T, press- totalk, and click-to-chat.

Background Nextel Communications began to develop its cellular services based on Motorola’s iDEN™ (integrated Digital Enhanced Network) technology. One of these services, Direct Connect SM push-to-talk.

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Nextel operates the first commercially available push-to-talk system, which works only on Motorola’s iDEN platform. Because the iDEN network was built entirely by Motorola to be compatible with Direct Connect, it does not have the same limitations as other technologies.

IP Radio Service The systems that enable iDEN network-based, multimediaenhanced communications services, is offering a push-to-talk solution called IPRS (IP Radio Service). The IPRS technology permits s to conduct unlimited international and roaming pushto-talk sessions across any packetbased network. IPRS is based primarily on client software that can be ed into most of the newer smart phone environments, such 14

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as Sun Microsystems, Inc.’s, J2ME™ (Java 2 PlatformMicro Edition) or QUALCOMM, Inc.’s, BREW™ (Binary Runtime Environment for Wireless™), or that can be embedded in the handsets by the handset vendors. “In peer-to-peer sessions voice transmission is routed directly between clients” . An IPRS server connected to the IP backbone performs duties such as authenticating s; managing voice calls; originating and terminating calls; and providing O&M (operation and maintenance), billing, and provisioning capabilities.

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Push-to-Talk Over Cellular Network Architecture

GPRS Gateway Node (GGSN) GPRS Gateway Node (GGSN) is network node that acts as agateway between a GPRS wireless data network and other networks such as the Internet or private network The GGSN is the anchor point that enables the mobility of the terminal in the GPRS/UMTS networks. In essence, it carries out the role in GPRS equivalent to the Home Agent in Mobile IP. It maintains routing necessary to tunnel the Protocol Data Units (PDUs) to the SGSN that service a particular MS (Mobile Subscriber).Other function include subscriber screening, IP Pool management andaddress mapping, QoS and PDP context enforcement.

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SGSN - Serving GPRS Node The Serving GPRS Node keeps track of the location of an individual MS (Mobile Station) and performs security functions and access control. The SGSN also exists in a UMTS network, where it connects to the RNC (Radio Network Controller) over the Iu-PS interface.

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Base Tranceiver System (BTS) Base Tranceiver Station. Technical term for a mobile phone base station. A BTS contains the transmit and receive technology and also the aerials to supply a radio cell. Several BTSs are istered by a BSC (Base Station Controller), which is in turn under an MSC (Mobile Switching Center). Existing BSCs and BTSs can be extended for new radio technology to allow the network operator to reuse existing aerial sites for UMTS radio networks.

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In radio communications a Base station is a two-way radio installation in a fixed location, used to communicate with one or more mobile or portable radio transceivers. They are typically used by low-power two-way radios such as mobile phones, portable phones and wireless routers. For example, the signals from one or more mobile telephones in an area are received at a nearby base station, which then connects the call to the land-line network. In the case of a portable phone, the connection is typically direct to a land line. Base stations can be local controlled or remote controlled. Local controlled base stations are operated by front controls on the base station cabinet. Remote control base stations can be operated over tone- or DC- private line telephone circuits or radio links.

Base Station Cellsite (BSC) In radio communications a Base station is a two-way radio installation in a fixed location, used to communciate with one or more mobile or portable radio transceivers. They are typically used by low-power two-way radios such as mobile phones, portable phones and wireless routers. For example, the signals from one or more mobile telephones in an area are recieved at a nearby base station, which then connects the call to the land-line network. In the case of a portable phone, the connection is typically direct to a land line. In the context of land surveying, a base station is a GPS receiver at an accurately known fixed location which is used to derive correction information for nearby portable GPS recievers. This correction data allows propagation and other effects to be corrected

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out of the position data obtained by the mobile stations, which gives greatly increased location precision and accuracy over the results obtained by uncorrected GPS recievers. In the area of wireless computer networking, a base station is a radio receiver/transmitter that serves as the hub of the local wireless network, and may also be the gateway between a wired network and the wireless network. Base stations can be local controlled or remote controlled. Local controlled base stations are operated by front controls on the base station cabinet. Remote control base stations can be operated over private line telephone circuits or radio links.

A professional rack-mount iDEN Base Radio at a Cell Site

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A typical consumer-grade CB base station

Mexicoose-up of a base station antenna

IP Multimedia Subsystem (IMS)

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The IP Multimedia Subsystem (IMS) is a standardised Next Generation Networking (NGN) architecture for telecom operators that want to provide mobile and fixed multimedia services. It uses a Voice-over-IP (VoIP) implementation based on a 3GPP standardised implementation of SIP, and runs over the standard Internet Protocol (IP). Existing phone systems (both packet-switched and circuit-switched) are ed. The aim of IMS is not only to provide new services but all the services, current and future, that the Internet provides. In this way, IMS will give network operators and service providers the ability to control and charge for each service. In addition, s have to be able to execute all their services when roaming as well as from their home networks. To achieve these goals, IMS uses open standard IP protocols, defined by the IETF. So, a multimedia session between two IMS s, between an IMS and a on the Internet, and between two s on the Internet is established using exactly the same protocol. Moreover, the interfaces for service developers are also based on IP protocols. This is why IMS truly merges the Internet with the cellular world; it uses cellular technologies to provide ubiquitous access and Internet technologies to provide appealing services.

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Features Of IP Based Architecture Because most emerging push-to-talk technologies are deployed on advanced packetbased networks, they are able to offer many features in addition to traditional push-to-talk capabilities. Although features among individual technologies or products may vary, most features are common to all products. For example, s can create and manage individual and group lists and use only one number for both push-totalk and regular calls. The rollout of IP-based push-to-talk services will allow nationwide and even worldwide push-to-talk sessions without special upgrades. Similar to “buddy lists” used in instant messaging computer programs, IPbased push-to-talk solutions create a presencebased communications environment that indicates a ’s status, in the figure. It shows whether the is connected and available to talk, is busy, or is not connected. If the is unavailable or busy, s can leave voice or text messages

IP-Based Push-to-Talk

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A Key technology of iDEN phones Time Division Multiple Access (TDMA) iDEN phones use several communications technologies. An iDEN phone's primary communications technology is Time Division Multiple Access (TDMA). A TDMA transmission divides an iDEN phone's signal into three parts, thereby decreasing the individual load of each stream. European units use the Global System for Mobile Communication (GSM) standard, which separates the stream into eight parts. There is also a smaller version of this technology called Harmony. Time Division Multiple Access is a air interface technology is used in GSM, as a digital upgrade of the AMPS analog system in the U.S. and as the basis of Personal Handyphone System (PHS) in Japan. TDMA is especially popular in the Americas. The technology divides each cellular channel into three time slots, tripling the data capacity from analog technology. TDMA was first specified as a standard in EIA/TIA Interim Standard 54 (IS54). IS-136, a version of IS-54, is the U.S. standard for TDMA for the 850MHz and 1.9 GHz spectrums. PHS was first introduced in Japan in 1995; intended as a worldwide standard, it never made it outside of the domestic market.

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How Does iDEN Work in PTT iDEN enables communications to begin with the press of a PTT button on the handset, rather than through completion of a standard cellular call. A call is formed by combining separate point-to-point connections between each IP endpoint at a managing entity known as the iDEN Applications Server, deployed on the provider’s IP-based Wide Area Network (WAN). Pressing the PTT button originates a call to the target iDEN and provides the originator with information indicating the availability of the target . Target s can be identified and programmed into handsets by the or a network . If the target is available, the originator receives an immediate indication (e.g., audible tone, message on the display) and the originator can begin speaking. The call originator’s voice is then sent through the carrier’s network to the target’s handset. Initiating a call to a iDEN who isnot available simply results in a negative response tone rather than a busy signal or entry into a voicemail function.

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What Are the Advantages of iDEN iDEN uses VoIP architecture, subscribers using standard 3G CDMA data networks worldwide2 will be able to push a button to talk. For instance, a iDEN in Boston could make a direct push-to-talk connection with another iDEN subscriber in Beijing... iDEN enables end s to set up iDEN groups dynamically from the handset without the need for action from a system . The iDEN application benefits from CDMA’s inherent security attributes. Since CDMA signals are digital in nature and transmitted across a wide bandwidth (as opposed to transmission over discrete frequencies), it possesses a low probability of interception and a low probability of detection, thus ensuring that transmissions are resistant to decoding and eavesdropping.

• iDEN offers these advantages • for over-the-air upgrade of iDEN client software via the wireless feature. • Dynamic management of group hip by subscribers (i.e., the ability to add or remove participants at any time, on their handset) • Ad hoc creation of chat groups on the handset, in addition to the standing groups that an may establish. • Easy implementation of the interface across multiple device types and in multiple languages.

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Other PTT Technologies and Their Relationship to iDEN iDEN is an evolutionary technology based on the PTT technologies that exist in today’s communication industry – in private two-way LMR systems and some commercial wireless services such as QChat. QChat is currently being used as backup form of voice communications for public safety field personnel, such as emergency response and police officers. iDEN’s functionality is very similar to QChat. To be more specific, iDEN is a high-capacity digital trunked radio technology that can provide integrated voice and data services to s. iDEN is based on TDMA technology to split a 25 kilohertz frequency into six separate time slots. Using half-duplex and full-duplex signals. iDEN is able to provide the following services: • Cellular-like telephony • Short Text Messaging • Digital two-way radio, one-to-one and group, and limited dispatch capabilities • Wireless data access. The iDEN digital two-way radio service uses a half-duplex signal, similar to that of QChat. A normal cellular telephone call uses a full-duplex scheme (i.e., two separate channels, one to send and the other to receive) for each call. In contrast, a Direct Connect call uses a single channel. Direct Connect relies on the proven technology of PTT, which is commonly used in dispatch-based radio systems. PTT is a simplex or half-duplex form of communications that requires the person speaking to press a button while talking and

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then release when they are finished. The listener then presses his or her PTT button to respond. This simplex or half-duplex access method allows the system to easily discern which direction the signal should be traveling.

Some of the major 2G digital air interfaces:

• Global System for Mobile Communications (GSM): A digital cellular phone technology that uses TDMA transmission techniques, it is sometimes referred to as Wideband TDMA. GSM is a circuit-switched system that divides each 200kHz channel into eight 25kHz time-slots. GSM operates in the 900MHz and 1.8GHz bands in Europe and the 1.9GHz PCS band in the US. Unlike CDMA or TDMA, GSM defines the entire cellular system, not just the air interface. GSM also s short messaging service (SMS), which enables text messages of up to 160 characters in length to be sent to and from compatible phones. SMS is probably the most successful wireless data service in the world at the moment. The GSM Association has said that around 3 billion SMS messages are sent each month. GSM s data transfer speeds of up to 9.6 kbit/s and has become the de facto standard in Europe and Asia. Over 80 percent of the world’s mobile phone subscribers use GSM-compatible phones.

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• Code-Division Multiple Access (CDMA): A "spread spectrum," digital, cellular, air interface technology mainly used in the U.S. and parts of Asia, such as South Korea. CDMA sends multiple signals or streams of information at one time as a single signal and then unravels the separate strands at the receiving end. CDMA operates in the 800MHz band and 1.9GHz PCS band and s data transfer speeds of up to 14.4 kbit/s. The world is demanding more from wireless communication technologies than ever before as more people around the world are subscribing to wireless. Add in exciting Third-Generation (3G) wireless data services and applications – such as wireless email, web, digital picture taking/sending, assisted-GPS position location applications, video and audio streaming and TV broadcasting - and wireless networks are doing much more than just a few years ago. This is where CDMA technology fits in. CDMA consistently provides better capacity for voice and data communications than other commercial mobile technologies, allowing more subscribers to connect at any given time, and it is the common platform on which 3G technologies are built. CDMA is a "spread spectrum" technology, allowing many s to occupy the same time and frequency allocations in a given band/space. As its name implies, CDMA (Code Division Multiple Access) assigns unique codes to each communication to differentiate it from others in the same spectrum. In a world of finite spectrum resources, CDMA enables many more people to share the airwaves at the same time than do alternative 29

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technologies.The CDMA air interface is used in both 2G and 3G networks. 2G CDMA standards are branded cdmaOne and include IS-95A and IS-95B. CDMA is the foundation for 3G services: the two dominant IMT-2000 standards, CDMA2000 and WCDMA, are based on CDMA. • Integrated Digital Enhanced Network (iDEN): iDEN is a proprietary version of the digital TDMA system developed by Motorola Inc. The technology has proved something of a dead end, even though it can both packet- and circuit-switched data and offers data transfer rates of up to 10 kbit/s • Cellular Digital Packet Data (CDPD): A wireless data-only packet overlay for the existing analog AMPS network in the U.S., CDPD shunts data over unused intervals in the voice channels. It has a data transfer rate of 19.2 kbit/s. Cellular Digital Packet Data (CDPD) uses unused bandwidth normally used by AMPS mobile phones between 800 and 900 MHz to transfer data. Speeds up to 19.2 kbit/s are possible. Developed in the early 1990's, 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.

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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. 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 three 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.

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Next Generation Our newest phones-like the i90c-feature innovative J2ME™ technology enabling you to interactive content and applications-from high-powered business tools to graphically rich games. Motorola's iDEN phones are truly the next generation of communications. If you are interested in developing J2ME applications for the Motorola IDEN phones please visit the Developer Program.

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Integrated Digital Enhanced Network also known as iDEN, is a mobile communications technology, which provides its s the benefits of a trunked radio and a cellular telephone. This technology is developed by the mobile company “Motorola” and is sold by the retailer Nextel which is the largest US retailer of iDEN services. Data like text message and picture message and voice communications are ed by iDEN. iDEN currently is at software release 13.0, ing 2500 sites maximum per urban. In order to provide high data rates for packet data, Nextel started to develop a 2.5G technology called WiDEN. Unfortunately, not many areas have for iDen technology. There are only twelve countries – Argentina, Brazil, Chile, China, Colombia, the Dominican Republic, El Salvador, Israel, Japan, Jordan, Korea, Mexico, Peru, Philippines, Saudi Arabia, Singapore, and the United States – currently capable of working with the system.

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Reference http://www.trillium.com. http://www.wikipedia.com http://www.motorola.com/ http://www.geocities.com/5peter/iDEN.html

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