In the passive optical network (PON) system, the optical line terminal (OLT) assigns bandwidth to each optical network unit (ONU) in accordance with the traffic condition at an ONU. The OLT needs to predict the remote ONU's required bandwidth. We give consideration about the error margin in the bandwidth prediction, and point out a problem in the future high-bit-rate PON and propose an enhanced queue status reporting method. (C) 2007 Optical Society of America.