Techniques for generating and transmitting packets on multiple links in a wireless communication system are described. In one aspect, a transmitter generates new packets for the multiple links based on the likelihood of each link being available. The transmitter determines the likelihood of each carrier being available based on whether or not there is a pending packet on that carrier and, if yes, the number of subpackets sent for the pending packet. The transmitter generates new packets such that packets for links progressively less likely to be available contain data units with progressively higher sequence numbers. The transmitter determines whether each link is available and sends a packet on each link that is available. In another aspect, the transmitter generates and sends new packets in a manner to ensure in-order transmission. In one design, the transmitter generates new packets for each possible combination of links that might be available.