What is the future of the TDMA wireless interface? The issue is far from trivial. TDMA serves more than 60 million digital and 15 million analog customers and stands as the number-one technology in terms of subscribers, operators and coverage in the Americas. Moreover, its operators represent a major force in choosing equipment and handsets for a third-generation (3G) migration.
Some industry executives have enthusiastically announced “TDMA’s demise,” citing recent decisions by a few TDMA operators to migrate to Enhanced Data Rates for Global Evolution (EDGE) and Universal Mobile Telecommunications Service (UMTS) through GSM/General Packet Radio Service (GPRS) overlays. This perception conveniently overlooks major financial and technological realities that give TDMA prominence for years to come. First, and most important, TDMA will continue to provide its operators with a sound basis for a successful business plan as most current TDMA operators will continue to rely on TDMA as a large source of cash flow, revenue growth and profits.
In fact, an often overlooked section of U.S. carrier AT&T Wireless’ release on its new strategy includes a pledge that its TDMA network will “continue to be supported, maintained and expanded, as needed, to deliver the reliable, high-quality, second-generation (2G) voice and data services that have made AT&T Wireless an industry leader.” Worldwide TDMA subscriber numbers increased more than 70 percent in 2000, and by some estimates, are expected to increase to 140 million by 2005.
Technologically, the decision by some TDMA operators to deploy a GSM/GPRS overlay has generated further momentum toward multiple, interoperable and convergent 2G and 3G solutions for the TDMA and GSM communities. TDMA operators that deploy a GSM overlay on their networks will continue to benefit from TDMA’s spectral efficiency for advanced voice services.
Meanwhile, GPRS will provide a commercial wireless data service with speeds of 64 kilobits per second (kbps) to 144 kbps. In addition, this GPRS overlay provides the foundation for 3G alignment with the GSM evolution path to EDGE and UMTS, providing future of economies of scale and global roaming.
In time, TDMA operators may eventually phase out TDMA equipment to avoid the parallel maintenance of two systems in a divided spectrum band. However, to lessen disruption to paying 2G customers, this will not be achieved overnight and could realistically be years away. The move toward TDMA-based technology convergence allows the TDMA technology to finally be on the center stage. The research firm Ovum in an August 2000 report predicted that by 2004, when analog subscribers will have fallen to a mere 3 percent, TDMA-based wireless technologies (GSM, PDC, TDMA) are expected to represent 79 percent of global wireless subscriptions.
The acceleration of TDMA-GSM convergence occurs even as analysts are beginning to question non-TDMA-based 2G technologies. These analysts are now recognizing that more than 70 percent of the world’s wireless subscribers are heading toward interoperability and convergence via the TDMA technology highway.
The decision in Singapore not to deploy a CDMA IS-95 network, the cancellation of CDMA IS-95 deployment in Taiwan (reported in the Tapei Times), the CDMA IS-95 deployment delays in China and especially the vacant cdma2000 license in CDMA IS-95 stalwart South Korea are further indications of the power of TDMA and GSM converged wireless standards. As the TDMA technology evolutionary path continues to align closely with GSM, truly global services based on TDMA-based technologies will begin to emerge.
While some TDMA operators are taking advantage of the changing global dynamics to offer higher wireless data rates through a GSM/GPRS overlay, TDMA will continue to prove its worth by bringing in large revenue streams to operators and vendors that are critical to funding 3G deployments. The wireless industry is ever changing, unpredictable and exciting, but with at least one certainty: TDMA will be serving customers on robust and diverse networks well into the foreseeable future.
Chris Pearson is executive vice president of the Universal Wireless Communications Consortium, which represents TDMA operators worldwide. He can be contacted at chris. pearson@uwcc.org.
