Title :
Maximum likelihood decoding for wavelet packet modulation
Author :
Suzuki, Noriyoshi ; Fujimoto, Mitoshi ; Shibata, Tsutayuki ; Itoh, Nobuo ; Nishikawa, Kunitoshi
Author_Institution :
Toyota Central Res. & Dev. Labs. Inc., Aichi, Japan
Abstract :
The multi-carrier modulation (MCM) technique is an attractive approach for high-speed digital radio communication systems in order to achieve a high spectral efficiency and to combat the frequency selectivity of the channel. Orthogonal frequency division multiplexing (OFDM) is a kind of MCM technique. Wavelet packet modulation (WPM) is another kind of MCM technique using the wavelet transformation instead of the Fourier transformation to multiplex information symbol sequences. In this paper we propose a maximum likelihood decoding method for WPM without coding before transmitting the signal. The proposed method performs maximum likelihood sequence estimation by utilizing a signal obtained in an intermediate stage of the demultiplexing process. Then, bit error performance under a flat fading channel and frequency-selective fading channel is evaluated by computer simulation. According to the results, the proposed method can improve the bit error performance in the region of high Doppler frequency
Keywords :
OFDM modulation; demultiplexing; digital radio; error statistics; fading channels; maximum likelihood decoding; maximum likelihood sequence estimation; mobile radio; wavelet transforms; Doppler frequency; MCM; OFDM; bit error performance; computer simulation; demultiplexing; flat fading channel; frequency-selective fading channel; high-speed digital radio; maximum likelihood decoding; maximum likelihood sequence estimation; multi-carrier modulation; orthogonal frequency division multiplexing; spectral efficiency; wavelet packet modulation; wavelet transformation; Computer errors; Demultiplexing; Digital communication; Digital modulation; Fading; Maximum likelihood decoding; Maximum likelihood estimation; OFDM modulation; Signal processing; Wavelet packets;
Conference_Titel :
Vehicular Technology Conference, 1999. VTC 1999 - Fall. IEEE VTS 50th
Conference_Location :
Amsterdam
Print_ISBN :
0-7803-5435-4
DOI :
10.1109/VETECF.1999.800316