Title :
High rate OFDM-modem with quasi-coherent DAPSK
Author :
Rohling, Hermann ; Brüninghaus, Karsten
Author_Institution :
Inst. of Telecommun., Tech. Univ. Braunschweig, Germany
Abstract :
An OFDM system with 64-DAPSK (differential amplitude and phase shift keying) modulation is considered. The performance with quasi-coherent demodulation is analysed in AWGN and frequency-selective Rayleigh fading channels with and without channel coding (convolutional coding) and compared to incoherent (64-DAPSK) and coherent (64-QAM) demodulation. It is shown that in contrast to coherent demodulation, no pilot symbols are required for quasi-coherent demodulation. Using this redundancy for additional channel coding, both coherent and quasi-coherent demodulation show approximately the same performance at the same net bit rate, but due to the relatively complex channel estimation the hardware complexity is considerably higher with coherent demodulation
Keywords :
Gaussian channels; Rayleigh channels; amplitude shift keying; channel coding; convolutional codes; demodulation; differential phase shift keying; fading; frequency division multiplexing; modems; quadrature amplitude modulation; 64-DAPSK; 64-QAM; AWGN channel; OFDM system; bit rate; channel coding; channel estimation; coherent demodulation; convolutional coding; differential amplitude and phase shift keying; frequency-selective Rayleigh fading channel; hardware complexity; high rate OFDM-modem; incoherent demodulation; performance; quasi-coherent DAPSK; quasi-coherent demodulation; AWGN; Amplitude modulation; Channel coding; Convolutional codes; Demodulation; Fading; OFDM modulation; Performance analysis; Phase modulation; Phase shift keying;
Conference_Titel :
Vehicular Technology Conference, 1997, IEEE 47th
Conference_Location :
Phoenix, AZ
Print_ISBN :
0-7803-3659-3
DOI :
10.1109/VETEC.1997.605959
