This post is about checking the interference on the GSM-R cell by command. Please read further down for the explanation.
You can run the DSP CHNJAM command to display the channel interference band level of a specified BTS. This command is mainly used to query the interference band level of idle channels and to monitor channel interference in real time.
The interference band is the uplink interference level of a channel reported by the BTS to the BSC through the RF RESOURCE INDICATION message when the channel is idle.
There are 5 levels of interference bands:
Interference band 1: -110 dBm to -106 dBm;
Interference band 2: -105 dBm to -99 dBm;
Interference band 3: -98 dBm to -93 dBm;
Interference band 4: -92 dBm to -88 dBm;
Interference band 5: -87 dBm to -47 dBm;
NULL: Not supported.
The NULL value means that the BTS does not report the interference band to the BSC if channels are unconfigured, blocked, faulty, or occupied, or if the channel type is not TCH, SDCCH, combined BCCH, or SDCCH_CBCH.
The higher the interference band level, the higher the interference level. Generally, if an idle channel falls in interference band level 4 or 5, the interference is counted.
