Note: The power control is used only in this section. When considering other sections, the power control feature should be deactivated.
A power control feature is implemented within SEAMCAT. When this feature is activated it introduces a variation of the interefering link transmitter power. More details on the implementation of the power control in SEAMCAT is presented in ANNEX 14:.
When using the scenario provided in section 3 (Victim Link and Interfering Link operate at the same frequency 1000 MHz but with a interfering link receiver antenna gain should be equal to 11 dBi), it becomes possible to define the distance between the Victim link receiver and the Interefering link transmitter.
For simplification, we consider that the Victim link receiver and the Interefering link transmitter are defined using the following assumptions (1 km distance between the Victim and the Interefering link transmitter). This is illustrated in Figure 138.
Figure 138: Setting up the distance between the Interfering and the Victim pair of
transmitter and receiver
If the power control is not activated then the iRSSunwanted is (see Figure 139):
iRSSunwanted = 33 (dBm) + 11 + 9 - (32.5 + 10 log(1) + 20 log(1000)) = -39.5 dBm
Figure 139: iRSSunwanted without power control
The same assumption is used for the distance between ILT and the ILR (i.e. x = 0 km and y = 1 km) where the ILT is the (0,0) origin as shown in Figure 140.
Figure 140: Setting up the distance between the Interefering link transmitter and the Interfering link receiver to evaluate the dRSSInterfering link receiver.
The power received by the Interfering link receiver (dRSSInterfering link receiver) is then:
dRSSInterfering link receiver = 33 (dBm) + 11 + 11 - (32.5 + 10 log(1) + 20 log(1000)) = -37.5 dBm
Note: You should not confuse the dRSSInterfering link receiver and the dRSSVictim link receiver. Figure 115 illustrates their differences.
The power control can be input as shown in Figure 141.
Figure 141: Setting up the power control for the interfering link.
Using these assumptions, the results of the simulation are the same as previously since the threshold (-35 dBm) is above the dRSSInterfering link receiver(-37.5 dB). This corresponds to the Case 1 described in ANNEX 14:.
Now, if the threshold is decreased from –35 dBm to –50 dBm (see Figure 142)
Figure 142: Reduction of the minimum threshold in the PC
Since, the power control feature is activated the gain of the power control is determined according to the guidance given in ANNEX 14: on page 330. Since the dRSSInterfering link receiver is –37.5 dBm and:
-50 dBm (PC threshold) + 2 * PC step (5 dB) < –37.5 dBm < -50 dBm (PC threshold) + 3 * PC step (5 dB)
The gain of the power control (git PC) is 10 dB (Case (i+1) in ANNEX 14:). This means that the iRSSunwanted will be decreased by 10 dB, i.e. :
iRSSunwanted = -39.5 dBm - git PC = -49.5 dBm
Finally, if the threshold is decreased from –50 dBm to –70 dBm, the power control feature is activated. Since the dRSSInterfering link receiver is –37.5 dBm, this results in:
-70 dB (PC threshold) + 20 (PC dyn) < –37.5 dBm
The gain of the power control is 20 dB (Case (n_step + 2) in ANNEX 14:). This means that the iRSSunwanted will be decreased by 20 dB, i.e. :
iRSSunwanted = -39.5 dBm - git PC = -59.5 dBm