Then, the feedback frame arranged as described above is transmitted from {HEAD ~ the reception side} to {TAIL ~ the transmission side} 
to
Then , the feedback frame arranged as described above is transmitted from { HEAD ~ the reception side } to { TAIL ~ the transmission side }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL