The service, called Comcast High-Speed 2go, will give the cable operator another tool in its competition with large telecom vendors such as Verizon and AT&T. Comcast already offers home-based voice and broadband services.

"With Comcast's wideband Internet, we already offer one of the fastest wired connections available today," Cathy Avgiris, Comcast's senior vice president and general manager for wireless and voice services, said in a statement. "Now with the launch of High-Speed 2go, we also deliver the nation's fastest wireless Internet."

Comcast plans a nationwide deployment of this WiMax service. Comcast's service, provided through Clearwire's wireless broadband network, is expected to be in 80 U.S. markets by the end of 2010, a Comcast spokeswoman said.

Comcast customers will be able to buy wired and wireless broadband together for US$49.99 per month over the next year, the company said. New and existing Comcast customers can also buy the so-called 4G wireless broadband service for as low as $30 a month.

The $49.99 Fast Pack Metro bundled service includes Comcast's 12M bps home broadband service, a Wi-Fi router and 4G service that will provide up to 4M bps download speed away from home. For an additional $20 per month, customers can upgrade to the Fast Pack Nationwide service that includes the same services plus nationwide 3G mobile network access.

Comcast, in late 2005, was among several cable companies that signed a $200 million, 20-year agreement with Sprint Nextel to develop wired and wireless broadband products. In May 2008, Clearwire, backed by Comcast and other companies, announced a $14.5 billion joint venture with Sprint to deploy the first nationwide mobile WiMax network.

Comcast's 4G service will be provided by the Clearwire network, and its 3G service will be provided by Sprint's nationwide 3G network.

"Comcast didn't want to get into the wireless business, but because of competition has to do so," said Jeff Kagan, an independent telecom analyst. "If they don't they will lose customers to AT&T and Verizon, who do offer that bundle."

Kagan called Comcast's first wireless broadband attempts with Sprint a failure. "This is the second pitch in the big game," he said. "I think their chances of success are pretty strong if they market this new service correctly. It will compete with Comcast wireline high-speed internet service. Customers will choose one or the other, but probably not both wireless and wireline Internet service."