Disclosed is a method of sub-packet adaptation based on data rate. Specifically, the size of a sub-packet is adapted to a data rate at which the sub-packet is to be transmitted. In one embodiment, the sub-packet is size adapted to the data rate in a format that would allow such size adapted sub-packet to be soft combined with another sub-packet of a same or different size. The size adapted sub-packet may be transmitted prior to or after the other sub-packet.