Google is planning to enter the lucrative mobile market, according to a Wall Street Journal report.

Google has invested a lot on mobile phone projects, including developing prototype handsets, proposing to operators, and talking with phone manufacturers over technical specifications. It hopes to have products manufactured base on its specification and multiple carriers to offer the services.

The plan is a double-edged sword to operators – more subscribers may be brought in due to Google's brand, but it may also dilute operators' control over the mobile advertising market.

Google has claimed clearly that it is serious about developing advanced software and services for mobile phones. "What's interesting about the ads in the mobile phone is that they are twice as profitable or more than the non-mobile phone ads because they're more personal," according to Google Chief Executive Eric Schmidt at the D: All Things Digital conference in May.

Google's efforts on cellphones in the past have brought in some concerns in the industry. Verizon Wireless has claimed that they will not be involved with the cellphone project because “Google's demands to get a large share of search-based ad revenue,” according to Lowell McAdam, Chief Executive of Verizon Wireless.