( ( ( A ( common factor ) ) ( in ( ( all ( these approaches ) ) ( to ( small cells ) ) ) ) ) ( ( is ( that ( they ( are ( centrally ( managed ( by ( mobile ( network operators ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT A) (JJ common) (NN factor)) (PP (IN in) (NP (NP (PDT all) (DT these) (NNS approaches)) (PP (TO to) (NP (JJ small) (NNS cells)))))) (VP (VBZ is) (SBAR (IN that) (S (NP (PRP they)) (VP (VBP are) (ADJP (RB centrally) (VBN managed) (PP (IN by) (NP (JJ mobile) (NN network) (NNS operators)))))))) (. .)))
A common factor in all these approaches to small cells is that they are centrally managed by mobile network operators.
(ROOT (S (NP (DT All) (NNS cells)) (VP (VBP have) (NP (NP (DT the) (JJ small) (NN size)) (PP (IN in) (NP (JJ common))))) (. .)))