MULTILEVEL CODING WITH ADAPTIVE EQUALIZATION AND INTERLEAVING FOR FADING CHANNEL

In high-speed digital land mobile radio communication, communication q uality is degraded by frequency selective fading that has intersymbol interference, It causes increase of bit error rate (BER). To decrease BER in the channel, this paper proposes a system with combined multile vel coding and adaptive equalization using interleaving. By using inte rleaving: the proposed system obtains time diversity effect. Furthermo re the system realizes a type of decision feedback adaptive equalizer where a signal after multilevel decoder is fed back. These features of the system cause decrease of BER. The proposed system is compared wit h a similar system with a feedback signal before multilevel decoder. T he average bit error rate of the proposed system is less than 1/100 wi th that of the compared system at average E(b)/N-o = 22 [dB] in a case of fading channel with one intersymbol interference.