Adjacent Channel Interference
Definition
Adjacent channel interference is the degradation of a communication channel caused by energy from a nearby channel bleeding into the wanted signal path.
Key Points
- It comes from signals in nearby channels.
- It is common in dense wireless and satellite environments.
- It depends on filtering, spectral shape, and coordination.
- It reduces effective carrier quality and capacity.
- It can force conservative modulation or spacing choices.
Concept
Adjacent channel interference is a frequency planning problem. Even if a channel is nominally separate, real-world filters, amplifiers, and emissions can spill energy into the next channel. The tighter the reuse plan, the more important spectral masks, coordination, and receiver selectivity become.
Explainer
For satellite and wide-area networks, adjacent channel interference is one of the practical constraints on reuse and density. It can reduce C/I, consume link margin, and force operators to trade capacity for stability. In a crowded environment, the ability to keep neighboring channels clean is often as important as the raw number of channels available.
Cite this entry
Adjacent Channel Interference. ConnectedEarth Knowledge Base. https://connectedearth.space/knowledge-base/adjacent-channel-interference/ (updated 13 September 2026).