Thanks PIX for explanation i saw in one of technical ALU doc and i copied exactly what wrriten below that make me some how not getting the idea
Example:
GSM 900, a mix BTS sector configuration is considered:
ANc combined with 4 TRA (TRAs = EGPRS capable TRE):
TRE 1 (BCCH): 60W GMSK (25W in 8-PSK)
TRE 2..4: 45W GMSK (15W in 8-PSK)
BS_TXPWR_MAX = 2 dB;
RESULTS:
1st step: Output power at BTS antenna connector (after combiner and
duplexer stage):
TRE 1 GMSK = 43.4 dBm; 8-PSK = 39.6 dBm
TRE 2..4 GMSK = 42.1 dBm; 8-PSK = 37.4 dBm
2nd step: LEVELING (BTS automatic GMSK power balancing):
TRE 1..4 GMSK = 42.1 dBm (Sector GMSK power)