LQI is defined in the G3 Specification as: SNR (dB)= LQI*0.25 -10 You can use following guideline for LQI and channel quality:
LQI Range SNR (dB) Typical Modulation Channel Quality 0 - 48 <2 ROBO Bad 49 - 52 2 - 3 ROBO/BPSK Weak 53 - 60 3 - 5 BPSK Medium 61 - 76 5 - 9 QPSK Good 77 - 108 >9 8PSK Excellent