▁environment , ▁the ▁existence ▁of ▁multi user ▁increases ▁the ▁inter - user ▁inter ference ▁possibility ▁that ▁can ▁affect ▁quality ▁and ▁performance ▁of ▁the ▁system ▁advers ely . ▁In ▁mobile ▁communication ▁systems ▁the ▁multip ath ▁problem ▁is ▁one ▁of ▁the ▁basic ▁problems ▁that ▁base ▁stations ▁have ▁to ▁deal ▁with . ▁Base ▁stations ▁have ▁been ▁using ▁spatial ▁divers ity ▁for ▁comb ating ▁f ading ▁due ▁to ▁the ▁severe ▁multip ath . ▁Base ▁stations ▁use ▁an ▁anten na ▁array ▁of ▁several ▁elements ▁to ▁achieve ▁higher ▁select ivity . ▁Rece iving ▁array ▁can ▁be ▁directed ▁in ▁the ▁direction ▁of ▁one ▁user ▁at ▁a ▁time , ▁while ▁avoid ing ▁the ▁inter ference ▁from ▁other ▁users . ▁▁ ▁Medical ▁applications ▁Array ▁processing ▁techniques ▁got ▁on ▁much ▁attention ▁from ▁medical ▁and ▁industrial ▁applications . ▁In ▁medical ▁applications , ▁the ▁medical ▁image ▁processing ▁field ▁was ▁one ▁of ▁the ▁basic ▁fields ▁that ▁use ▁array ▁processing . ▁Other ▁medical ▁applications ▁that ▁use ▁array ▁processing : ▁dise ases ▁treatment , ▁tracking ▁wave forms ▁that ▁have ▁information ▁about ▁the ▁condition ▁of ▁internal ▁org ans ▁e . g . ▁the ▁heart , ▁local izing ▁and ▁analyz ing ▁brain ▁activity ▁by ▁using ▁bio - mag net ic ▁sensor ▁arrays . ▁▁ ▁Array ▁Process ing ▁for ▁Spe ech ▁En h ancement ▁Spe ech ▁enh ancement ▁and ▁processing ▁represents ▁another ▁field ▁that ▁has ▁been ▁affected ▁by ▁the ▁new ▁era ▁of ▁array ▁processing . ▁Most ▁of ▁the ▁ac oust ic ▁front ▁end ▁systems ▁became ▁fully ▁automatic ▁systems ▁( e . g . ▁tele ph ones ). ▁However , ▁the ▁oper