1. A communication method in carrier aggregation comprising:allocating, by a first base station, first and second data allocation information according to a user equipment (UE) category describing a combination of a downlink capability and an uplink capability;
sending, by the first base station, first data to the UE according to the first data allocation information determined according to the UE category of the UE;
instructing, by the first base station, a second base station to send second data to the UE according to second data allocation information determined according to the UE category, wherein the second base station performs carrier aggregation with the first base station; and
simultaneously communicating, by the first base station, with the UE and the second base station, wherein a total amount of the first data sent by the first base station and the second data sent by the second base station to the UE in a same transmission time interval (TTI) does not exceed a total amount of data that can be received by the UE according to the UE category.