Matched median filter for detecting QAM signals

The complex matched median filter, (MMF) is developed for quadrature amplitude modulation (QAM) signal detection under the maximum likelihood criterion. It is shown that MMF has the so-called robustness property similar to median filters in case of impulsive noise. Based on the combination of the MMF and the linear matched filter (LMF), extended matched filters are also introduced. These filters have properties of both an MMF and an LMF and behave well in a varying environment. Computer simulations demonstrated that the proposed detectors give a smaller detection error probability than the LMF when impulsive noise is present