Interference cancellation, other upgrades double capacity of the CDMA channel

LAS VEGAS--For much of the CTIA Wireless show this week, Qualcomm was looking to the future, pointing to key customer wins for its Gobi embedded laptop radio chip, talking up Snapdragon for even smaller devices and assuring the industry that MediaFLO will continue to expand. But Qualcomm also brought out an old standby, CDMA 1X, unveiling new enhancements to the stalwart technology that will double voice capacity and ultimately make room for 3G data channels.

Qualcomm has incorporated reverse-link interference cancellation technology into its latest release of CDMA base station chips, which—along with a few other technical tweaks—clear up enough capacity on the 1.25 MHz channel to double call volume from the typical 35 sessions. While the improvements affect only voice capacity, they potentially will have a big impact on data capacity. By making voice channels more efficient, Qualcomm officials said, operators can shrink the number of channels devoted to 1X voice and add EV-DO carriers, thus boosting their broadband data capacity considerably.

Though Sprint and Verizon Wireless won’t reveal the extent of their EV-DO Revision A rollouts, they likely only have one 1.25 MHz channel of EV-DO rolled out in most of their markets. The cost of deploying a second EV-DO carrier is not only high, but since EV-DO can only transmit and receive IP data, any 3G expansion would require those operators to sacrifice voice capacity. The impact of this is especially pertinent to Sprint, which plans to roll out its push-to-talk service over the Rev. A network this quarter. Based on Qualcomm’s Qchat technology, DirectConnect uses VoIP over the Rev. A channel. If usage of the service approaches anywhere near that of its Nextel push-to-talk service, data capacity demands will be considerable.

Sprint and other CDMA operators will have to wait a little while for the upgrade, though. The first chipset line incorporating the enhancements—which Qualcomm oddly calls the CSM8xxx series—won’t start interoperability testing and commercially shipping until 2010. From there they have to be incorporated into the manufacturer’s base stations and then deployed in new networks.

As for Gobi, the deployments will come much sooner. Qualcomm said that that several vendors, including Dell Computer, have already begun embedding its UMTS and EV-DO data radio solutions in their laptop, and in the US, T-Mobile and Verizon Wireless have begun certifying those products.