Dual connectivity based on listen before talk information

A base station apparatus comprising:

• one or more processors;
• memory storing instructions that, when executed by the one or more processors, cause the base station to:
• receive from a second base station, an application protocol message comprising radio resource status information of one or more licensed assisted access (LAA) cells of the second base station, wherein the radio resource status information comprises at least one listen before talk (LBT) parameter based on one or more results of one or more LBT processes performed by the second base station on the one or more LAA cells;
• decide to request the second base station to allocate radio resources for a bearer of a wireless device based on the at least one LBT parameter;
• transmit to the second base station, a request message to add the second base station for dual connectivity of the wireless device;
• and
• transmit to the wireless device, configuration parameters of a cell group comprising the one or more LAA cells for communication with the second base station.