The vision of the third-generation (3G) wireless network sounds like something out of a science fiction novel. 3G proponents say it will be one big, ubiquitous network that carries all kinds of traffic: voice, data and Internet service. It will allow total mobility, with the same services available no matter what kind of access device is used and no matter where the user is located. Any wireless phone will work anywhere in the world, and users will be able to access the Internet wirelessly at speeds rivaling high-bandwidth fixed Internet connections.
However, although the 3G vision has been discussed for years, this next-generation network isn't here yet. The groundwork, however, is being laid. While that single big network doesn't yet exist, the networks that are in place are evolving and preparing for the 3G future that lies ahead.
Several wireless Internet services that could be considered steps toward 3G are already available for users. In the United States, AT&T is offering cellular digital packet data (CDPD) services that provide Internet information over a wireless packet network to mobile phones. Sprint also offers wireless Internet access using an Internet Protocol-based circuit-switched connection. The Mobitex wireless data network has evolved to offer wireless data access for pagers and Palm VII devices.
In Japan, NTT DoCoMo's i-Mode mobile Internet service is the biggest wireless Internet success story in the world, with about 10 million subscribers expected before the end of this year. NTT DoCoMo is signing up about a million new subscribers per month, including both new wireless subscribers and people who were already using another wireless service. In fact, it has been so successful that NTT is considering curbing the number of new subscribers until the infrastructure can be upgraded to handle demand. I-Mode offers many of the services touted for 3G-wireless e-mail, online banking and Internet access-all providing on-the-go convenience. The success of i-Mode demonstrates that there is a market for wireless Internet access. I-Mode is already Japan's top Internet service based on number of subscribers, topping even established wired-line services.
In addition to those early wireless data efforts, General Packet Radio Service (GPRS) technology is part of the first step toward 3G. Primarily a software upgrade to the Global System for Mobile Communications (GSM) wireless networks that provide mobile phone service in much of the world, GPRS provides mobile users with access to Internet information. It is a natural part of the migration path to 3G and uses the same basestations as GSM with a modification of software and the addition of support nodes, plus a link to a packet data network.
Currently, GPRS is in trials around the world. Ericsson alone had 45 GPRS field trials in progress at the end of 1999.
Every vendor today selling data networks in conjunction with GPRS implementations must address plans for providing the data services necessary for an evolution to true 3G. Data and voice network operators are already preparing for this transition. British Telecom is in the early stages of a network evolution to carry all traffic, including voice, as data on a packet backbone supported by ATM. Telefonica in Spain is carrying packetized voice traffic on its data network. Standards organizations also are preparing for this network evolution. The Third Generation Partnership Project (3GPP) working group of the International Telecommunications Union is working out the issues surrounding wireless packet voice, such as quality of service, security and voice quality. That group is also working with the Internet Engineering Task Force because the issue requires a blending of the telecommunications and Internet worlds.
The data network that carries wireless traffic must be of a different grade than past data networks. These networks must meet the rigorous quality standards of a carrier-class network-99.999% reliability. Although these networks are being built using data technologies such as Internet Protocol and asynchronous transfer mode (ATM), they will be expected to operate like telecommunications networks, with redundant hardware, robust and resilient software and in-line servicing for nonstop operation. Because they will be carrying Internet traffic, these networks must be able to carry large volumes of data traffic without disrupting the integrity of other services provided by the network. Although the telecommunications world is moving away from circuit switching, operators aren't yet ready to give up their legacy circuit-switched infrastructure. Operators are using ATM technology to support legacy traffic simultaneously with Internet Protocol-based data traffic. This is a key element in the network implementation Ericsson is conducting for British Telecom, for example.
One technology developed in the data world to help data networks transition toward 3G is the software-based packet switch, sometimes called a softswitch. This is critical for voice-over-packet traffic. A softswitch is essentially software that performs the functions of a telephone switch. It replaces the circuit switch, emulating many of its functions in directing voice traffic but adding flexibility and features unique to packet traffic. Instead of the point-to-point traffic direction of a circuit switch, a softswitch can function almost like an Internet Web site, aggregating content from a variety of sources to provide new services to users, such as access to online address and phone books that are network-based, so they can be accessed from anywhere. Judging from the status of softswitch development, it will be about six months before trials of packetized voice deployments based on the softswitch are seen, but most major telecom vendors have some form of deployment plan in the works.
Although today's GPRS network deployments don't yet need all of this functionality from data networks, it's not too soon to begin considering those factors. The data networks will need to be ready for the next step in wireless data. The Universal Mobile Telecommunication System, or wideband CDMA (W-CDMA), as it's known in the United States, was designed specifically for wireless Internet Protocol communications and is generally considered to be "true" 3G wireless. It's the next step in the evolution toward the full 3G network and it's already starting. Initial deployment is expected by 2002.
In the United States, Enhanced Data rate for Global Evolution (Edge) technology will bridge the gap between Time Division Multiple Access (TDMA) networks and the GSM networks more common in the rest of the world, to provide a degree of global roaming for wireless users. Edge is the evolution of GSM and TDMA into a system capable of a 384-kbits/s data rate. Edge will allow GSM and TDMA to converge into a global network in which roaming across international and technological boundaries is possible. The first Edge deployments are expected in the second half of 2001.
Another 3G technology is CDMA2000. It will begin deployment in the same time frame, providing capacity improvements and data capabilities for existing CDMAOne systems and end-users.
As the wireless access aspects of the 3G network are developed, it is equally critical for the Internet Protocol backbone network to continue to evolve.
Expect the 2004 worldwide communications network to look very different from the one that exists today.
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