A digital
overlay covering method includes a
down link trunking and an up link
trunking, wherein the
down link trunking includes: receiving the signals,
processing the signals, packing the framing digital signals, transmitting to a plurality of covering units through the
optical fiber or five line transmissions, decoding the frame, completing the
signal coverage transmitted by the antenna; the up link trunking comprises: receiving the
signal,
processing the
signal, packing the framing
digital signal, transmitting to the access unit through the
optical fiber or five line transmissions, decoding the frame, transmitting to the
base station system through the antenna of the access unit or the potical
fiber / five line transmissions. The invention also provides a digital
covering system. The method and the
system of the invention adopt the
digital signal processing, the
digital signal transmission, the digital distribution, reduce the loss and the
noise of the signal. An access unit is added at the entrance of the building, transmitted to the inside of the building through the wiring, and the coverage unit is accessed at the required position, namely reaching the requirement to be compatible of the multi-
system and multi-frequency range, to complete the coverage of the signal.