The EU is an expansion unit, whose main functions include:
Receiving downlink baseband data sent by the DU, and sending it to the radio frequency unit RU after processing;
Processing the radio frequency data from the uplink unit and sending it to the CU/DU after certain combination processing;
Incorporating a power supply circuit to supply power to the radio frequency unit RU through an optical-electrical hybrid cable;
Supporting cascading between expansion units;
Supporting compression and decompression.
