Efforts to take millions of users of Time Division Multiple Access (TDMA) cellular networks over to Internet-ready mobile-phone systems are accelerating as proponents of two rival wireless technologies claim new converts. Over the past few months, a group supporting the Code Division Multiple Access (CDMA) digital cellular standard has announced that eight TDMA operators in the Americas and Asia have migrated to the CDMA2000 platform as a way to build third-generation (3G) wireless services. Meanwhile, the Global System for Mobile (GSM) standard camp says leading TDMA operators in both North and South America are deploying its infrastructure specifications for 3G. EMC, a wireless market research firm, estimates that TDMA subscribers worldwide exceeded 100 million as of July this year. The Americas account for 96 per cent of all TDMA users. In Hong Kong, PCCW runs a TDMA network it obtained when it bought the business of rival Pacific Link several years ago. Operations of the mainland's existing TDMA networks have been in the hands of the military for years. TDMA is a cellular standard that supports both analog and digital communications over the 850 megahertz and 1.9 gigahertz radio spectrums. TDMA is also used for digital cordless-phone systems used in both residential and corporate environments. CDMA, developed by Qualcomm in the United States, refers to any of several protocols used in second-generation (2G) and 3G wireless communications. The technology is used in ultra-high-frequency cellular telephone systems in the same 800 MHz and 1.9 GHz bands used by TDMA networks. The original CDMA standard, also known as CDMA One, offers a data transmission speed of up to 14.4 kilobits per second. Its Internet-ready platforms, CDMA2000 and wideband CDMA, deliver data many times faster. GSM is the de facto wireless standard in Europe, where it was developed, and in many parts of Asia. It is a standard that uses a variation of TDMA techniques operating at the 900 MHz, 1.8 GHz and 1.9 GHz bands. An upgraded version of this standard is called General Packet Radio Services (GPRS), known as a 2.5G technology that lays the groundwork for a GSM network to provide 3G services with high-speed data transfer rates of up to two megabits per second. According to EMC, there were more than 705 million GSM subscribers at the end of the second quarter this year to continue leading all wireless technology deployments. GSM is now used in more than 75 per cent of the world's digital wireless phones and provides an unmatched roaming footprint spanning more than 550 networks in more than 175 countries. EMC also found that GSM and TDMA combined represented 118 million customers in the Western Hemisphere and 808 million customers globally at the end of the second quarter this year. Despite that hefty GSM user base, the CDMA Development Group (CDG) says that the CDMA2000 platform empowers existing TDMA operators to set up an advanced digital wireless system with minimal investment in their network and maximum service benefits. The CDG is a non-profit trade association formed to foster the worldwide development, implementation and use of CDMA One and CDMA2000. The group has more than 100 member-companies, including many of the world's largest wireless operators and telecommunications equipment manufacturers. CDG executive director Perry LaForge says former TDMA operators who hae migrated to CDMA include Telecom New Zealand, Bell Mobility, BellSouth International Ecuador, BellSouth International Panama, Movilnet, Telecom Mobile, US Cellular and Verizon Wireless Puerto Rico. 'TDMA operators find themselves at a critical juncture. Faced with swapping out their networks for a stronger evolutionary path, these carriers must be sure that the decisions they make today will maximise their return on investment in the future,' Mr LaForge says. 'The CDMA2000 path provides a technically and economically optimal solution, especially for TDMA operators in Latin America, the majority of which use the 800 MHz spectrum.' Unlike the GSM route, CDMA2000 is touted as providing 'a seamless one-step migration path' to 3G and has proven benefits such as increased capacity and delivery of revenue-generating, high-speed data applications. 'CDMA2000 increases the capacity of TDMA networks by four to six times, and since CDMA2000 uses the same core network as TDMA, there are substantial cost savings for operators and service transparency for end-users,' Mr LaForge says. To date, CDMA2000 800 MHz infrastructure has been deployed around the world for over two years and at present more than 100 of the 800 MHz CDMA devices are supplied by 10 manufacturers. There are 26 commercial CDMA2000 networks around the world and 20 more will be deployed in coming months, Mr LaForge says. China Unicom, the mainland's second-biggest mobile telephone company, has started operating its CDMA One network and is expected to move to 3G using the CDMA2000 platform. Meanwhile, the 3G Americas group, which advocates the migration of TDMA systems to GSM-evolved 3G infrastructure, claims a steady conversion rate even as TDMA network users continue to grow. 'We are seeing tremendous gains in GSM subscribers in the Americas, where existing GSM operators continue to expand and where TDMA operators are implementing the overlay of GSM-GPRS technologies,' 3G Americas executive vice-president Chris Pearson says. 'The adoption of GPRS, and the increased availability of wireless data service applications, bodes well for the future of all GSM operators throughout the Americas. 'We saw the launch of the first wireless photo-messaging services in the Americas this past quarter by a GSM-GPRS operator and tremendous growth of text messaging used by TDMA and GSM customers.' Mr Pearson says GSM is expected to continue growing at an exponential rate as more operators commit to the 3G GSM evolution. TDMA operators in North America - AT&T Wireless, Cingular and Rogers Wireless - are committed to the GSM-evolutionary path to 3G, he says. In South America and the Caribbean, TDMA operators in Argentina, Bermuda, Brazil, Mexico and Peru have also confirmed their adoption of the GSM technology strategy. 3G Americas unites wireless operators and vendors in North America and South America to promote, educate and advocate the success of GSM, TDMA, GPRS and other next-generation wireless technologies. The founding members of 3G Americas include AT&T Wireless, Cingular Wireless, Ericsson, Hewlett-Packard, Lucent Technologies, Motorola, Nokia, Nortel Networks, Openwave Systems, Canada's Rogers Wireless, Siemens and Telecom Personal in Argentina. EMC research manager Michael Woolfrey says: 'Despite the general slowdown in subscriber growth across the Americas, GSM-TDMA grew its market share. 'The two technologies now account for over 52 per cent of all users in the Americas region, compared to 48 per cent as of June last year.'