LG U8138 Service Manual page 220

E. TX Open Loop Power Control Calibration
- Purpose
The purpose of the calibration of open loop power control is to store parameters for the Open Loop
Power Control algorithm. This is a pure off-line calculation. Use data (positions and output power, in
dBm) from table 0. Curve fitting should be done preferably with minimum square method.
System related requirements:
Open loop power control
Maximum allowed UL TX Power
UE Transmitted power
- Procedure proposal
1. Create a curve fitting for the low-gain region, use positions with a power greater than -50 dBm:
Position = B3 * Pout + A3
2. Extract A3 and B3.
3. The power level (output power) at the highest position in the low-gain region sets the parameter P2.
4. Divide the high-gain region into two regions at the split between mid-gain and high-gain. The output
power at this position sets the parameter P1.
5. Do a curve fitting for the mid-gain region (where RFBias > 0) of the high-gain region, use power-
levels from P2: Position = B2 * Pout + A2
6. Extract A2 and B2
7. Do a curve fitting for the high-gain region (where RFBias = 0) of the high-gain region:
Position = B1 * Pout + A1
8. Extract A1 and B1
9. Save A1, A2, A3, B1, B2, B3, P1 and P2 in GD_RF_TX_GAIN_PARAM_ID.
Figure 8-2. Example of Position versus Power and Calculated Equations
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8. CALIBRATION