In this invention wireless communication of data between a user equipment and a base station including bandwidth aggregation of a plurality of component carriers, includes a first unit transmitting on a first component carrier a grant control signal the other unit specifying a second component carrier different to transmit the typically via a carrier indication field of 3 bits. The carrier indication field can be a one-to-one mapping to each possible second component carrier of a component carrier offset from an anchor carrier, which could be the first component carrier.