The object of the present invention is to avoid disconnection of a radio link between the radio base station and the mobile station even when the mobile station moves while transmitting no up signals in a case where the radio base station transmits the directional beam. The radio base station according...http://www.google.com/patents/US20040137952?utm_source=gb-gplus-sharePatent US20040137952 - Communication method using directional beam and radio base station
