Title :
Effects of imperfect channel information on adaptive loading gain of OFDM
Author :
Su, Qiang ; Schwartz, Stuart
Author_Institution :
Dept. of Electr. Eng., Princeton Univ., NJ, USA
fDate :
6/23/1905 12:00:00 AM
Abstract :
The performance of OFDM system in mobile wireless channels can be enhanced by introducing adaptive loading schemes: information bits are distributed unequally in subchannels according to the channel frequency response. Under the assumption of perfect channel estimation, considerable gain can be achieved over the non-adaptive loading scheme for typical channels. If there are channel estimation errors in the system, the adaptive loading gain will be adversely affected in proportion to the MSE of the errors. The effect of channel mismatch due to Doppler spread is also studied. The results show that adaptive loading can preserve most of its gain even with imperfect channel information.
Keywords :
Doppler effect; OFDM modulation; adaptive systems; frequency response; land mobile radio; mean square error methods; parameter estimation; telecommunication channels; Doppler spread; MSE; OFDM system; adaptive loading gain; channel estimation errors; channel fading; channel frequency response; channel mismatch; imperfect channel information; mobile wireless channels; nonadaptive loading; perfect channel estimation; subchannels; Adaptive systems; Channel estimation; Channel state information; Delay estimation; Electronic mail; Frequency response; OFDM; Sampling methods; System performance; Transmitters;
Conference_Titel :
Vehicular Technology Conference, 2001. VTC 2001 Fall. IEEE VTS 54th
Print_ISBN :
0-7803-7005-8
DOI :
10.1109/VTC.2001.956644
