A method, comprising: establishing, by a processor of an apparatus implemented in a user equipment, UE, a connection over a downlink component carrier and a first uplink component carrier with a network apparatus; establishing, by the processor of the apparatus, a connection over a second uplink component carrier with the network apparatus; assigning, by the processor of the apparatus, the first uplink component carrier as a primary carrier and assigning the second uplink component carrier as a supplementary carrier; receiving, by the processor of the apparatus, a command from the network apparatus; and transmitting, by the processor of the apparatus, uplink data to the network apparatus via at least one of the first uplink component carrier and the second uplink component carrier, the method further comprising: when the command contains multiple bits having a predefined value, aggregating at least the first uplink component carrier and the second uplink component carrier to form aggregate in an event that the multiple bits correspond to at least the first uplink component carrier and the second uplink component carrier; and when the command contains a single bit having the predefined value, switching the primary carrier from the first uplink component carrier to the second uplink component carrier in an event that the single bit corresponds to the second uplink component carrier and switching the primary carrier back from the second uplink component carrier to the first uplink component in an event that the single bit corresponds to the first uplink component carrier. establishing, by a processor of an apparatus implemented in a user equipment, UE, a connection over a downlink component carrier and a first uplink component carrier with a network apparatus; establishing, by the processor of the apparatus, a connection over a second uplink component carrier with the network apparatus; assigning, by the processor of the apparatus, the first uplink component carrier as a primary carrier and assigning the second uplink component carrier as a supplementary carrier; receiving, by the processor of the apparatus, a command from the network apparatus; and transmitting, by the processor of the apparatus, uplink data to the network apparatus via at least one of the first uplink component carrier and the second uplink component carrier, the method further comprising: when the command contains multiple bits having a predefined value, aggregating at least the first uplink component carrier and the second uplink component carrier to form aggregate in an event that the multiple bits correspond to at least the first uplink component carrier and the second uplink component carrier; and when the command contains a single bit having the predefined value, switching the primary carrier from the first uplink component carrier to the second uplink component carrier in an event that the single bit corresponds to the second uplink component carrier and switching the primary carrier back from the second uplink component carrier to the first uplink component in an event that the single bit corresponds to the first uplink component carrier. when the command contains multiple bits having a predefined value, aggregating at least the first uplink component carrier and the second uplink component carrier to form aggregate in an event that the multiple bits correspond to at least the first uplink component carrier and the second uplink component carrier; and when the command contains a single bit having the predefined value, switching the primary carrier from the first uplink component carrier to the second uplink component carrier in an event that the single bit corresponds to the second uplink component carrier and switching the primary carrier back from the second uplink component carrier to the first uplink component in an event that the single bit corresponds to the first uplink component carrier.