Techniques and examples of hybrid automatic repeat request (HARQ) buffer size design for communication systems are described. A user equipment (UE) communicates with a serving cell of a wireless network using a HARQ mechanism, with the communicating involving: (a) determining, by the processor, a respective size of each buffer of a plurality of buffers corresponding to a plurality of HARQ processes on a per-HARQ process basis; and (b) storing, by the processor, respective information in each buffer of the plurality of buffers for a corresponding HARQ process among the plurality of HARQ processes.