A licensed assisted access network system is provided. The licensed assisted access network system includes a mobile station and a first base station. The mobile station determines a use status of an unlicensed band and generates first available unlicensed channel group information. The mobile station transmits the first available unlicensed channel group information to the first base station. The first base station selects a first unlicensed channel according to the first available unlicensed channel group information. The first base station initializes a communication schedule assessment procedure with the mobile station through the first unlicensed channel.