An improved channel-aware clipped matched frequencymlfopping (CMFH) signaling technique in slowly fading dispersive channels
Said E. El‐Khamy, Filipe Batoni Abdalla, Akram Al‐Hourani · 2005
Matched frequency hopping signals (MFH) signals has been proposed recently as an efficient channel-aware signaling technique in slowly fading dispersive channels. The hopping patterns of slow frequency hopping (SFH) signals are designed to match the channel transmission characteristics such that the hopped frequencies are concentrated in frequency slots of minimum attenuation and hence resulting in enhanced performance. An improved technique is presented in this paper by utilizing clipping of the channel response and extending the modulation to MFSK instead of binary FSK in previous work. In clipped MFH (CMFH) systems, the selection of the frequency slots is improved by clipping the frequency response of the dispersive channels such as to correspond to a maximized transmission through them and reduced transmission through frequency channels of higher attenuation. An analytical study of the bit error rate (BER) of the MFH/MFSK spread spectrum signals and the (CMFH) is presented. In the case of CMFH, the performance is improved and compared to that of MFH without clipping. The results show the advantage of CMFH technique and its importance as an efficient channel-aware spread spectrum signaling technique