Interference Constraints
The Interference page enables you to set constraints in terms of certain link performance indicators as affected by interference. For example, if you set BER+I Max to a given value, access is excluded for periods during which BER, taking into account the effects of interference, exceeds that value. This is in contrast to the BER constraint under Communications, which would exclude access for periods during which BER exceeds the given value, irrespective of interference effects.
Before you can use these constraints, you must first define an interference environment with a CommSystem object that identifies the participating transmitters and receivers and the interference sources. If the scenario contains more than one CommSystem, you can select the CommSystem to be used for interference constraints on the scenario's RF Environment page.
STK uses the first CommSystem in the scenario unless another has been selected.
You can also opt to exclude time intervals that meet a given constraint.
| Field | Description |
|---|---|
| BER+I | This is the same as the Bit Error Rate (BER) constraint, but taking the effects of interference into account. |
| C/I | This is the carrier-to-interference ratio.
Due to the volatile nature of the C/I parameters, the sampling may not be able to precisely capture the threshold. |
| C/(N+I) | This is the same as the C/N constraint, but taking the effects of interference into account. |
| C/(No+Io) | This is the same as the C/No constraint, but taking the effects of interference into account. |
| DeltaT/T |
This is the interference-to-noise ratio, which is the ratio of jammer power spectral density to receiver noise power spectral density. Due to the volatile nature of the DeltaT/T parameters, the sampling may not be able to precisely capture the threshold. |
| Eb/(No+Io) |
This is the same as the Eb/No constraint, but taking the effects of interference into account. |
| J/S | This is the jamming-to-signal ratio, virtually the inverse of C/I. |
| Power Flux Density | This is the flux density computed over a reference bandwidth defined in the CommSystem. The options for the reference bandwidth are 1 MHz, 40 kHz, 4 kHz, and 1 Hz. |
| Total Pwr At Rcvr Input | This is the total power received at the input of the receiver front-end amplifier. It includes antenna gain, polarization mismatch, cable losses, etc. The total power is the sum of the desired signal power and all received interference signal power in the direction of the interferer and within the receiver’s bandwidth. |
| Total Rcvd RF Power | This is the total RF power received at the receiver antenna terminal, not accounting for antenna gains. This includes the power due to the main carrier and the powers due to the interferers/jammers in the receiver's line of sight. |