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