Latency is an important component in fifth generation (5G) study. In this paper, we focus on the latency reduction with short processing time. Short processing time is an effective way to reduce latency. The maximum time advance (TA) and transport block size (TBS) are introduced to shorten the processing time. Short processing time with frame structure unchanged results into less standardization efforts but is hard to support stricter requirement on latency such as less than 1ms.