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