An electronic device has wireless communications circuitry. The wireless circuitry may transmit and receive wireless signals over a network having first and second wireless base stations. The first base station may establish a primary wireless connection with the device using selected connection settings and may transmit the selected connection settings to the second base station. The second base station may copy the received connection settings to establish a secondary wireless connection with the device while the primary connection is simultaneously maintained. After the primary and secondary connections have been established, the first and second base stations may transmit data streams to the electronic device over different frequency bands in a carrier aggregation link. By using the second base station to copy the received connection settings that were used by the first base station to establish the primary connection, the connection time for establishing the carrier aggregation link may be improved.