Enhancements In Works For iDEN, CDMA Networks

Select wireless carriers will be able to squeeze more voice capacity and higher data rates out of their second- and third-generation (2G and 3G) networks, thanks to upgraded iDEN and CDMA 1X technology.

For 2G iDEN networks such as Nextel's, Motorola has developed upgrades that will double the voice capacity of iDEN networks and accelerate packet-data throughputs to 60kbps-70kbps from less than 19.2kbps. Nextel said the capacity expansion, combined with planned entry-level handsets, will enable it to "selectively expand its existing market segments," presumably by offering rate plans and handset prices that could expand its target customer base beyond business users to include consumer users.

For 3G CDMA2000 1X networks, Qualcomm is developing a combined handset/cell-site solution that will almost double the voice capacity of 1X networks, which already double the capacity of 2G CDMA networks. 2G CDMA networks, in turn, deliver more than 10x the capacity of analog cellular networks.

Here's what the iDEN and CDMA 1X enhancements will deliver:

iDEN: To accelerate data throughput, Motorola developed a network-based data-compression upgrade that will deliver data at 60kbps-70kbps to existing and future iDEN phones. iDEN carrier Nextel said it will begin rolling out faster data service throughout its network early in 2002.

Turbocharged data service won't deliver data noticeably faster if a subscriber accesses Web-based information through a handset's microbrowser, but faster data rates will be noticeable if a subscriber uses a phone as a wireless modem to access data through a connected laptop. A spokeswoman also said the faster data speeds would "prepare Nextel for new [wireless-data] applications."

Nextel expects to offer expanded voice capacity in 2003, but to enjoy the benefits, Nextel subscribers will have to buy new phones that the carrier wants to begin offering sometime in 2002.

Also in 2002, the company hopes to offer low-cost Motorola-made iDEN handsets that could be used, in combination with expanded network capacity, to penetrate "new market segments" and "extend [Nextel's] business competitiveness," a company statement said. Those handsets might also be available in 2002, the spokeswoman added.

On an everyday basis, Nextel handsets currently start at $99, or $49 during promotions, she said. Presumably, lower cost phones would enable Nextel to offer handsets at $49 or less on an everyday basis with less subsidization, but the spokeswoman wouldn't comment.

Although the carrier hasn't yet selected a 3G technology, the interim steps will "give us more time" to analyze 3G options, assess the experiences of overseas 3G operators, and "potentially give us the ability to leapfrog current 3G technologies," she said.

CDMA 1X: The handset/network solution developed by CDMA-inventor Qualcomm can be applied to the CDMA 1X standard and to future standards such as CDMA 1xEV-DV, which in itself doesn't increase voice capacity over 1X but does accelerate data rates to 3-5Mbps, said Roberto Padovani, Qualcomm's executive VP for R&D.

The solution doubles voice capacity when the upgraded handsets are widely deployed, and data rates will also accelerate, but tests to quantify the data-efficiency increase isn't set to begin for a couple of months.

Network equipment is available to implement the solution because existing base stations and Qualcomm chipsets will support the upgrades, Padovani said. Handsets that will let subscribers enjoy the benefits of the upgrades will be available in one and one-and-a-half years, the company said.

Qualcomm uses two techniques to boost voice capacity: voice compression and dual-antenna/dual-receiver handsets combined with diversity-reception techniques in a cell site's base-station receivers.

The handsets would incorporate the usual external send/receive antenna and a second receive-only antenna, likely to be internal, Padovani explained. "The phone will now be able to receive a duplicate copy of the signal from the two receiving antennas," Padovani said. Signal-processing techniques will then combine the two signals to maximize the signal-to-interference ratio. "This increased signal strength at the phone translates directly into a reduction of the required transmitted power from the base station to this phone to maintain an equivalent grade of service," he continued.