A mixed signal spectrum clearing system for radio co-existence with high power jamming

High power jamming systems employ very nonlinear and highly efficient power amplifiers. In order to create a clean frequency space to allow radio communications in the jamming spectrum, one must be able to create an agile notch in the output spectrum of such jamming systems. The agile notch must be able to follow the hopping patterns of FHSS systems. The generation of this agile notch is hindered by very large intermodulation products present in the output spectrum. The intermodulation products can only be removed through nonlinear estimation of PA characteristics. This paper presents architecture for enabling such co-existence based on transmitter intermodulation cancellation in a very narrow spectrum. Such narrow band feedback strategy is essential if the system is to be realizable with current A-D and filtering technologies. We demonstrate through a theoretical and architectural study that such a system is indeed realizable and can lead to effective communications in the presence of high power jammers.