The U.S. Patent and Trademark Office has published three wireless-related patents filed by Google employees as the search giant seeks to delve deeper into the wireless market.

The patent applications, filed by Google employees Wesley Chan, Shioupyn Shen and former Google product management director Georges Harik, propose lowering the cost of wireless access by offsetting the costs via advertisements on the service. Google, which receives the bulk of its revenue from advertisers, is seeking to expand its potential advertising base by moving further into the wireless market.

The patent applications, filed in 2004 and published earlier this month, address three issues related to the wireless and advertising market.

Patent application No. 20060058019 seeks to develop a system for dynamically modifying the appearance of browser screens on a client device when connecting to a wireless access point. Under the patent, the browser's appearance would be modified to reflect the brand associated with the wireless access-point provider.

The patent application says that Wi-Fi Internet access would be provided freely to customers in exchange for their agreement to receiving ads on their devices. Google, however, noted its patent applications do not represent a guarantee it will head in a particular direction with its technology.

"Like many companies, we file patent applications on a variety of ideas that our employees may come up with. Some of those ideas later mature into real products or services; some don't," a company representative said. "Prospective product announcements should not be inferred from our patent applications."

The two other patent applications, No. 20060059044 and No. 20060059043, cover ads based on wireless access points and wireless access at a reduced rate, respectively.

"The gap between what Wi-Fi operators charge and what casual mobile users are typically willing to pay is relatively significant," according to the patent applications. "Therefore, Wi-Fi Internet access as an industry has experienced a rather slow start."