A method, apparatus, processing system, and computer program product enable association of mis-aligned subframes from a first and second downlink with one another, such that a HARQ acknowledgment message including jointly encoded feedback for the respective subframes can be correctly interpreted by the corresponding cells. Here, an RNC may provide an RRC message to the UE to associate particular subframes with one another. Further, the RNC may provide NBAP messages to the cells transmitting the downlink signals, so that the cells can associate the HARQ acknowledgment message with the appropriate subframe. Still further, additional signaling provides for changing the set of associated subframes when needed due to a drift in the timing offset between cells.