CINR Level Comparison Troubleshooting First off, let’s start with a definition of CINR.
Carrier-to-Interference-and-Noise Ratio. The ratio between the power of the Radio Frequency (RF) carrier bearing the wanted signal and the total power of interfering signals and thermal noise. CINR levels are expressed in dB. Here is a chart of typical CINR Level ranges
Excellent above 22
Good 16 to 22
Fair 9 to 16
Poor below 9
Each RF chain has a CINR result. In the case of 2x2, Baicells expresses the two results as CINR1 and CINR2. These results should be very close together, for example CINR1=20 and CINR2=19. If they are not close together, it would be apparent some sort of attenuation is evident on one RF chain. Therefore, we need to troubleshoot the following items.
- RF path from eNodeB to antenna (water in RF cable, bad lightning protector, bad cable termination, bad cable)
- One radiator in the antenna is defective or disconnected internally (replace with another antenna to test)
- Bad UE (One antenna radiator is defective or disconnected internally or one transmitter is bad. Try another UE)
- RF interference on one RF chain (Try changing to a different frequency)
- Incorrect antenna downtilt or UE antenna is not mounted directly at the eNodeB antenna. (check antenna downtilt and vertical beamwidth in relation to UE location)
- UE mounted outside or at the edge of the eNodeB antenna propagation field. (move UE inside antenna propagation field)
- Bad eNodeB (One RF port is disconnected from the transmitter internally or a bad transmitter. Replace eNodeB)
It is possible to connect a UE with excellent CINR on one chain and less than desirable CINR on the other chain, however the bandwidth capability of the UE may be cut in half. If you are not seeing good bandwidth capacity, always check the CINR levels.