For example, {HEAD ~ a mechanism} is provided to enable {TAIL ~ access points} to perform automatic channel selection 
is provided to enable
For example , { HEAD ~ a mechanism } is provided to enable { TAIL ~ access points } to perform automatic channel selection
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH