The transceiver of claim 4, wherein the beam index selector calculates squared inner products vectors such as equation W t,k=???R i H A k???2(here, the H is an hermitian operator) from at least one adaptive beamforming weight vector Ak (k=0,1, . . . , K) selected from the per-channel adaptive beam weight vector selector; and the switched beamforming weight vectors Rj (j=0,1, . . . , L) of which nu