Just to throw some light on signal strength.
If i take example of "-67 dBm and 23 ASU"
-67 dBm is the RSSI(Received Signal Strength Indicator) it is used to show the signal bar in your phone. usually -60 dBm or greater will show full bar nad -110 dBm and lower will show one bar (it depends on the phone os implementation)
Now comes the ASU which is the main parameter to decide yor throughput.
ASU is Reference Signal Received Power (RSRP) and is a int value ranging from 0 97. For the range 1 to 96, ASU maps to
(ASU - 141) ≤ dBm < (ASU - 140).
The value of 0 maps to RSRP below -140 dBm and the value of 97 maps to RSRP above -44 dBm.
So higher the value better the data stability and no signal loss.
I work in LTE development and i have seen that although RSSI is -110 dBm (one bar) and ASU is 63 the throughput of data is good and stable.