Call drop caused by forward and reverse imbalance

Typical case:
MS received power and strongest pilot Ec/Io maintain in good state, such as Rx Power>-100dBm, Ec/Io>-15dB;
As MS moves, MS reverse Tx power is increasing continuously to 23dBm, until call drop happen;
As MS moves, MS Tx_Adj is increasing continuously and it is one positive value, until call drop happen;
After call drops, MS will initialize and stay in previous pilot. There is signal in MS, but origination call is difficult, even if origination is successful, call drop is very possible.

Analyzing:
In the above case, MS Rx power and pilot Ec/Io are all good, and this means the forward link is good. But in MS origination procedure MS is increasing transmitting power until maximum, and this means the reverse link is bad. That is forward and reverse imbalance. Tx_Adj>0 also means forward is better than reverse.
Because forward is better than reverse, so in the edge of coverage BTS can not receive the signal from MS correctly and BTS call drop mechanism is triggered, and then call drop will happen.

Note:
Forward and reverse link imbalance includes two kinds: forward is better than reverse; reverse is better than forward.
The above case is the former. It popular in practice and effect is large. Because subscriber can not tolerate that call failure and call drop happen when there is signal in MS, so this case should be cared for very much.

Optimization method:
Find the rootstock of imbalance:
For the case that forward is better than reverse:
Judge if the cell power configuration is too high;
Judge if the pilot gain is too high;

Judge if there is reverse interference;
For the case that reverses is better than forward:
Judge if the cell power configuration is too low;
Judge if the pilot gain is too low;
Judge if there is forward interference;