The method 5, wherein the grant specifies a transmission window on the optical line during which {HEAD ~ only the ONU} can transmit {TAIL ~ data} to the OLT 
transmit
The method 5 , wherein the grant specifies a transmission window on the optical line during which { HEAD ~ only the ONU } can transmit { TAIL ~ data } to the OLT
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH