Moment methods for diversity combining of fast frequency hopped noncoherent MFSK

The inherent repetition coding of fast frequency hopped M-ary FSK signals can be used to improve performance against interference such as jamming through diversity combining at the receiver. A new diversity combining approach is presented. The samples for each M-ary bin are processed by attributing any large or abnormal variations in these values to interference. An attempt is made to subtract this variation by the use of estimates of various moments. These moment methods are shown to be effective against jamming without the use of side information. Results are given which demonstrate that they are powerful countermeasures against both noise and multitone jamming