Intel's WiMax chip set proves power hungry

IDG News Service - Mobile broadband comes in different flavors, and the options are growing. Users can connect to the Internet through 3G networks, but now WiMax capabilities are being added to many laptops. WiMax (Worldwide Interoperability for Microwave Access) is a wireless technology that provides fast data-transfer rates over a wider area than Wi-Fi.

WiMax is already finding adoption in developing countries and is now reaching the U.S. through companies like Sprint and Clearwire. WiMax service is already available through adapters that can be plugged into laptop ports. Intel in early January introduced its latest WiMax/Wi-Fi Link 6250 internal chip set for laptops to access WiMax networks.

The chip set should provide faster data transfers than its predecessors and give longer battery life to laptops than external cards, said Tim Sweeney, an Intel spokesman. The second-generation WiMax silicon is more compact and has a high level of integration that boosts its performance.

I used a Dell Inspiron pre-production laptop with the chip set to test the data transfer rates and battery life. The data transfer rates were impressive when the chip set was connected to Clear's WiMax network in Las Vegas, but the laptop's battery life was short of expectations when the service was running.

Download speeds outpaced even my AT&T DSL connection at home. I watched a streaming video from Netflix, without choppy images, from multiple locations three miles apart. Even video from ESPN360's Web site, usually broken when viewed from my DSL home connection, was smooth on the WiMax connection.

The typical transfer speeds are expected to be 4Mbps to 6Mbps (megabits per second) for downloads and 1Mbps to 2Mbps for uploads on Clear's network, Intel said. There is room for improvement -- download speeds could reach 14Mbps or more and upload speeds could reach 4Mbps on the network, Intel said.

But the fast transfer speeds took a toll on the laptop's battery life. The battery indicator dropped down to around three hours when the Netflix video was playing, and jumped up to more than four hours when the WiMax service was idle. That said, battery life goes down under active Wi-Fi usage as well, which is very common with laptops.

The decrease in battery life with WiMax depends on the data transmission rates and the distance of a connection from the base station, Sweeney said.

"The farther away the client is from the base station, the more transmit power it must put out for the base station to receive or 'hear' it. It has to 'shout' louder to be heard by the base station due to the increased distance," Sweeney said. This is true for Wi-Fi as well, but in general the transmit power for a WiMax client will be higher, he said.