A null-steering adaptive array processor for voiceband HF links

An alternative to interference avoidance is interference cancellation with null steering adaptive arrays. Although this approach does demand additional antennas and receivers, it allows use of the entire channel bandwidth at occupied frequencies, provided the number of interfering signals is less than the number of array elements. A general purpose, null steering, adaptive array processor (AAP) for voiceband HF channels is currently under company-funded development at Rockwell International, Collins Defense Communications. It is expected that by adding this applique to existing, conventional (nonhopping) HF communication systems, significant performance improvements will be available through interference rejection