{TAIL ~ Channel detection} is accomplished by {HEAD ~ means} of counting the number of negative acknowledgements, which classifies the channel degradation level and determines which alternatives to be adapted in order to combat specific blockage phenomenon 
{ TAIL ~ Channel detection } is accomplished by { HEAD ~ means } of counting the number of negative acknowledgements , which classifies the channel degradation level and determines which alternatives to be adapted in order to combat specific blockage phenomenon
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH