Spectrum Survey in 2.4 GHz ISM Band for a MRT Station Located in Singapore

Recently, a spectrum survey was performed at a Mass Rapid Transit (MRT) station located in Singapore for the study of spectrum utilization in the 2.4 GHz ISM frequency band. The measurement results indicate that the 2.4 GHz ISM band is highly crowded by the WLAN signals and the CCTV signals in this MRT environment. The presence of WLAN signals and CCTV signals increases the potential of interference to the Communications-Based Train Control (CBTC) signals and therefore creates the risk of frequent failures in train control.An occupancy analysis is then carried out to study the severity of interference from those Non-CBTC signals to the CBTC signals. The results present that maximum occupancy in the 2.4 GHz ISM band could be up to 58.76 %, which is significant enough to introduce spectral congestion for the CBTC system.