Methods, apparatus and computer program products are provided for defining the HARQ functionality for primary and secondary cells having different TDD UL/DL subframe configurations so as to reduce or eliminate instances in which the feedback is blocked and the UL grant is missed. For example, a method is provided that includes providing for communications via a primary cell and at least one secondary cell in a time division duplex (TDD) network that supports carrier aggregation in accordance with different TDD uplink (UL)/downlink (DL) subframe configurations. In this example, the method also defines at least one of: (i) UL or DL hybrid automatic repeat request (HARQ) timing, (ii) a maximum number of DL HARQ processes, (iii) a number of UL HARQ processes or (iv) an UL HARQ process mapping to be the same for each of the primary and secondary cells having different TDD UL/DL subframe configurations.