{HEAD ~ The base station} 20, wherein {TAIL ~ each} of the plurality of mobile stations has a corresponding reference signal 
{ HEAD ~ The base station } 20 , wherein { TAIL ~ each } of the plurality of mobile stations has a corresponding reference signal
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH