Suffixes indicating action or process:
* -ing: Signalling (present participle, indicating ongoing action)
* -ed: Signaled (past participle, indicating completed action)
* -er: Signaler (one who sends signals)
* -ation: Signalization (the act or process of signaling)
Suffixes indicating quality or state:
* -less: Signal-less (without signals)
* -ful: Signal-ful (full of signals)
Other suffixes:
* -ance: Signalance (the act of signaling or the quality of being signaled)
* -ment: Signalment (a description or identification of someone or something)
The best suffix to use depends on the specific meaning you want to convey.