Thus {HEAD ~ high priority services} can pre empt the usage of wireless resources by {TAIL ~ low priority services} 
Thus { HEAD ~ high priority services } can pre empt the usage of wireless resources by { TAIL ~ low priority services }
OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL