The wireless cellular industry is abuzz about the potential of third-generation -- or 3G -- networks delivering higher bandwidths that are expected to usher in a broadbandlike wireless Internet.
The hope is that 3G networks will create the kind of buzz for a handheld, wireless Internet in the United States that the breakthrough iMode phone has generated in Japan. In just 15 months, DoCoMo has built its iMode service into a wireless powerhouse serving nearly 7m users -- subscribers who use the iMode phone, which has barely 19.2Kbps access to the Net, for everything from reserving karaoke rooms to downloading music. DoCoMo is expected to introduce 3G service within the next year.
3G phones won't be available elsewhere until at least 2002, but analysts are already doing the math. The Yankee Group estimates that there are 1.3 million users of wireless data devices in the United States -- and predicts that number will mushroom to more than 60 million by 2005.
But at least one analyst, Mike McGuire of Dataquest, feels that 3G has been overhyped to the point where users are expecting it to do things that it was not designed to do.
According to McGuire, rich multimedia experiences will not be possible via wireless until fourth-generation (4G) networks roll out in the next four or five years, although 3G wireless will be able to handle short, low-quality multimedia clips. Likewise, he said that, although the browsing of Web pages may be possible via 3G, it won't be easy.
"3G is not meant to be a primary synchronisation technology, rather query browsing was its focus. 4G with its wider pipes is more likely to be conducive to real browsing," McGuire said.
3G is an arbitrary term because, like the different cellular technologies, it doesn't have one set definition. Many cellular carriers are simply defining 3G by significant jumps in access rates.
AT&T, for instance, will be using Edge (Enhanced Data for GSM Evolution) to deliver 3G networks, providing, according to AT&T, a maximum rate of 384Kbps. "But that's if you're the only person using the network in a clear field standing near a cell tower," countered McGuire.
He has a point. 3G bandwidths will vary, depending on the number of users on the network at a given time and the distance from a cell tower. Rather than 384Kbps, McGuire anticipates users will typically get access at something more on the order of 56Kbps -- the equivalent of current telephone modem connections. AT&T spokespeople would not give a specific figure.
Looking ahead to 4G However, a recent tour of AT&T Labs revealed an interesting glimpse into the potential of the wireless Internet.
AT&T officials said that 4G, which will evolve from Edge, will provide downlink access of more than 384Kbps and uplink access of at least 384Kbps for wide area networks. In some cases, rates can reach as high as 10Mbps, when the network is used in conjunction with other technologies that AT&T is developing, but typical rates are expected to be several megabits per second.
"4G will help us realize one giant network where real convergence will happen. Cable TV, PC, cellular, basically any type of data transport all on one network, which you can access anywhere," said AT&T spokesman Ken Woo.
4G will be based on OFDM (Orthogonal Frequency Division Multiplexing), the key enabler of 4G technology. Other enablers include adaptive processing and smart antennas, both of which will be used in 3G networks and enhance rates when used in conjunction with OFDM.
Whereas 3G networks' digital data is sent over a single channel, OFDM will send data over hundreds of parallel streams -- increasing the amount of information that can be sent at a time.
4G rates will vary depending on the number of channels that can be accessed and processed. However, the channels that can be used will be cleaner thanks to technologies such as adaptive processing, which accounts for interference on a channel and improves reception by dynamically switching channels to avoid interference.
4G networks will also benefit from smart antenna technology, which can steer the radio signal in the direction of the receiver in the terminal from the base station. When used in conjunction with adaptive techniques, multiple antennas can cancel more interference while enhancing the desired signal.
The 4G plans are still years away, but transitioning from 3G to 4G should be seamless for customers because 4G will have evolved from 3G. Users won't even have to get new phones.
4G won't matter, though, unless AT&T gets its 3G act together. AT&T expects its 3G network to be up and running in one year in selected cities and nationwide by 2002.
In the meantime, AT&T Wireless Services and Nortel Networks have announced they will conduct noncommercial GPRS trials near several AT&T facilities this summer. The point of the trials is to gain experience with network design and deployment so that the 3G rollout will happen without a hitch. AT&T and its partners will test and run services and applications on the 2.5G network.
GPRS is the intermediary technology, otherwise known as the 2.5G protocol, for GSM and TDMA networks. Wireless carriers using CDMA are planning on rolling out 2.5G, offering 144Kbps rates, but AT&T has chosen to forgo 2.5G rollouts and instead invest and prepare for 3G.
Explaining AT&T's decision to leapfrog over 2.5G, Rod Nelson, chief technology Officer of AT&T Wireless Services, said there won't be any services or applications available when 2.5G rolls out later this year to take advantage of the increased bandwidth. And, he said, users will have to buy new handsets when 3G comes out because the transition from GPRS to EDGE will not be seamless.
Nelson also claimed AT&T is still ahead of its competitors because no other company can match its all-you-can-eat pricing plan.
According to analysts, if AT&T is wrong and applications are made available for 2.5G wireless devices, the telco could find itself playing catchup. In the short term, though, analysts say that all the carriers have to improve the number and quality of phones that will access the networks.
For instance, currently there are only two phones using the AT&T Wireless Internet service, and their screens are text-based -- making navigation a continuous scroll session.
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