HIGH CAPACITY DIGITAL MOBILE RADIO SYSTEM

摘要

A HIGH CAPACITY DIGITAL MOBILE RADIO SYSTEM The present invention relates to a mobile radio base station capable of communicating with a large number of mobile stations by implementing space diversity and time-division retransmission techniques in a digital communication system. The digital base station contains a plurality of antenna elements and a plurality of retransmission branches associated in a one-to-one relationship. When the base station receives a digital communication signal from a mobile station, each antenna element receives the signal with a unique random phase due to the effects of the environment on signal transmission. The signal is then processed through the plurality of retransmission branches, where each branch adapts to compensate for the random phase of the signal received by its associated antenna element. Conversely, when the base station transmits a signal back to the mobile station, each retransmission branch adds the conjugate of its associated random phase to the signal to be transmitted, allowing the environment to "undo" the effect of the conjugate random phase so that the signals transmitted by the plurality of antenna elements will arrive coherently at the mobile station.