Distributed antenna monitoring system

摘要

A distributed antenna system 200 connected to a base station 100 of a radio communications network has a number of distributed elements or repeating modules 300 each connected to an antenna for providing time and space diversity. An alarm monitor at the base station transmits a state enquiry message to each repeating module sequentially, inquiring whether the repeating module is out of order. An acknowledge message from each repeating module informs the alarm monitor of its operational state. The alarm monitor informs the base station of the state of each repeating module. Thus failure of any of the distributed elements is detected and the base station is informed. A failure detector connected to each repeating module checks whether the module is out of order by comparing a transmission signal voltage level to a reference level, and voltage level of a signal reflected from an antenna to a second reference level.