Comcast Corp is offering at least two Asian cellular operators access to its WiFi hot spots in the United States, in trial partnerships that illustrate the cable company’s ambitions to compete with U.S. wireless carriers. The deals with Japan’s KDDI and Taiwan Mobile allow their subscribers to use Comcast’s WiFi hot spots when they travel to the United States, reducing the international roaming charges that they would otherwise have to pay, according to a Comcast spokesman.