Diversity combining for FFH system with worst-case partial-band noise jamming

Two novel nonlinear combining algorithms, namely, dual nonlinear diversity combining (DNDC) and multi-threshold clipper combining (MTCC) are presented in this paper. In particular, for DNDC with the envelope detector, samples of each dehopped signal are weighted by the inverse noise powers and then clipped with a soft-limiter. The results are finally accumulated in the combiner. Likewise with MTCC, the receiver adaptively adjusts the clipper´s threshold with an estimation of the power of the jammer and the number of corrupted frequencies. The performance evaluation under worst-case partial noise jammer for different diversity combining algorithms is given to confirm that substantial diversity gain in terms of reduced error rate can be achieved by the use of the proposed algorithms