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Code Division Multiple Access

Posted by admin On March - 15 - 2008ADD COMMENTS

Code Division Multiple Access, a cellular technology orginally known as IS-95, competes with GSM technology for dominance in the cellular world.

There are now different variations, but the original CDMA is now known as cdmaOne.
Latest CDMA Global Subscriber & Operator Numbers
10 million new CDMA2000 subscribers were added in 3Q 2003
See other cellular technologies of the world
CDMA2000 Coverage & Operators

We now have cdma2000 and its variants like 1X EV, 1XEV-DO, and MC 3X. The refer to variants of usage of a 1.25Mhz channel. 3X uses a 5 Mhz channel.

Wideband CDMA that forms the basis of UMTS 3G networks, Developed originally by Qualcomm, CDMA is characterized by high capacity and small cell radius, employing spread-spectrum technology and a special coding scheme.

Developed originally by Qualcomm and enhanced by Ericsson, CDMA is characterized by high capacity and small cell radius, employing spread-spectrum technology and a special coding scheme.

CDMA was adopted by the Telecommunications Industry Association (TIA) in 1993. In September 1998, only three years after the first commercial deployment, there were 16 million subscribers on cdmaOne systems worldwide. By May 2001 there were 35 million subscribers on cdmaOne systems worldwide and there are now 60 million.

Over 35 countries have either commercial or trial activity ongoing. There are already 43 Wireless Local Loop (WLL) systems in 22 countries using cdmaOne technology.

Enhancing today’s data capabilities is the 1XRTT CDMA standard – this next evolutionary step for cdmaOne operators will provide data rates up to 300 kbps, significant capacity increases as well as extended battery life for handsets.

Worldwide resources are being devoted to roll out third-generation CDMA technology, including Multi-Carrier (cdma2000 1xMC and HDR in 1.25 MHz bandwidth), and 3xMC in 5 MHz bandwidth) and Direct Spread (WCDMA in 5 MHz bandwidth).

This first phase of cdma2000 – variously called 1XRTT, 3G1X, or just plain 1X – is designed to double current voice capacity and support always-on data transmission speeds 10 times faster than typically available today, some 153.6 kbps on both the forward and reverse links. (see more on cdma2000)

QUALCOMM owns a substantial portfolio of CDMA patents, including many “essential” patents that are necessary for the deployment of any proposed 3G CDMA system, such as Multi-Carrier, Direct Spread, and another system referred to as TD-SCDMA.

QUALCOMM has now granted royalty bearing licenses to more than 75 manufacturers for CDMA and, as part of these licenses, has transferred technology and know-how in assisting these companies to develop and deploy CDMA products.

A significant number of these companies’ licenses cover third-generation applications, including WCDMA, 1x and High Data Rate (HDR). Under terms of QUALCOMM’s existing 3G licensing agreements, a licensee will pay the same royalty to QUALCOMM for 3G systems, including WCDMA, TD-SCDMA and 1x, as that licensee pays QUALCOMM for today’s CDMA infrastructure, phones and test equipment.

Enhancing today’s data capabilities is the 1XRTT CDMA standard – this next evolutionary step for cdmaOne operators will provide data rates up to 300 kbps, significant capacity increases as well as extended battery life for handsets.

Worldwide resources are being devoted to roll out third-generation CDMA technology, including Multi-Carrier (cdma2000 1xMC and HDR in 1.25 MHz bandwidth), and 3xMC in 5 MHz bandwidth) and Direct Spread (WCDMA in 5 MHz bandwidth).

Global System for Mobile Communications

Posted by admin On March - 15 - 20081 COMMENT

GSM (Global System for Mobile communications) is an open, digital cellular technology used for transmitting mobile voice and data services. GSM differs from first generation wireless systems in that it uses digital technology and time division multiple access transmission methods. 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 and 850MHz bands in the US. The 850MHz band is also used for GSM and 3GSM in Australia, Canada and many South American countries. GSM supports data transfer speeds of up to 9.6 kbit/s, allowing the transmission of basic data services such as SMS (Short Message Service). Another major benefit is its international roaming capability, allowing users to access the same services when travelling abroad as at home. This gives consumers seamless and same number connectivity in more than 210 countries. GSM satellite roaming has also extended service access to areas where terrestrial coverage is not available.

EDGE Platform

Further enhancements to GSM networks are provided by Enhanced Data rates for GSM Evolution (EDGE) technology. EDGE provides up to three times the data capacity of GPRS. Using EDGE, operators can handle three times more subscribers than GPRS; triple their data rate per subscriber, or add extra capacity to their voice communications. EDGE uses the same TDMA (Time Division Multiple Access) frame structure, logic channel and 200kHz carrier bandwidth as today’s GSM networks, which allows it to be overlaid directly onto an existing GSM network. For many existing GSM/GPRS networks, EDGE is a simple software-upgrade.

EDGE allows the delivery of advanced mobile services such as the downloading of video and music clips, full multimedia messaging, high-speed colour Internet access and e-mail on the move.

Due to the very small incremental cost of including EDGE capability in GSM network deployment, virtually all new GSM infrastructure deployments are also EDGE capable and nearly all new mid- to high-level GSM devices also include EDGE radio technology. The Global mobile Suppliers Association (GSA) states that, as of May 2007, there were 223 commercial GSM/EDGE networks in 113 countries, from a total of 287 mobile network operator commitments in 142 countries.

3GSM Platform

3GSM is the latest addition to the GSM family. 3GSM enables the provision of mobile multimedia services such as music, TV and video, rich entertainment content and Internet access. The technology on which 3GSM services are delivered is based on a GSM network enhanced with a Wideband-CDMA (W-CDMA) air interface – the over-the-air transmission element. Global operators, in conjunction with the 3G Partnership Project (3GPP) standards organisation, have developed 3GSM as an open standard