DocumentCode :
427974
Title :
A combinational scheme of pre-FFT adaptive beamforming and frequency-domain adaptive loading for OFDM
Author :
Lei, Ming ; Zhang, Ping ; Harada, Hiroshi ; Wakana, Hiromitsu
Author_Institution :
Yokosuka Radio Commun. Res. Center, Nat. Inst. of Inf. & Commun. Technol., Yokosuka, Japan
Volume :
1
fYear :
2004
fDate :
26-29 Sept. 2004
Firstpage :
290
Abstract :
We propose a transmission scheme combined with orthogonal frequency division multiplexing (OFDM), adaptive beamforming and adaptive loading. Two adaptive beamforming schemes based on the least mean square (LMS) algorithm and pre-FFT combining are used to obtain the space diversity gain. Their difference lies in either using the frequency-domain or time-domain pilot vector in the beamforming. The beamforming scheme based on the time-domain pilot vector has comparatively low complexity. In order to counter the severe frequency-selective fading which is inevitable for broadband wireless communications with or without an adaptive antenna array, we use frequency-domain adaptive loading to load the bits and transmit power to the individual subcarriers. The performance investigations show the combinational, scheme based on the adaptive beamforming, and adaptive loading is very effective in decreasing the bit error rate (BER) for OFDM.
Keywords :
OFDM modulation; adaptive antenna arrays; array signal processing; diversity reception; error statistics; fading channels; least mean squares methods; BER; LMS; OFDM; adaptive antenna array; bit error rate; broadband wireless communications; frequency-domain adaptive loading; frequency-domain pilot vector; frequency-selective fading; least mean square algorithm; orthogonal frequency division multiplexing; pre-FFF combining; pre-FFT adaptive beamforming; space diversity gain; subcarrier transmit power; time-domain pilot vector; Adaptive arrays; Array signal processing; Bit error rate; Broadband antennas; Counting circuits; Diversity methods; Diversity reception; Least squares approximation; OFDM; Time domain analysis;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Vehicular Technology Conference, 2004. VTC2004-Fall. 2004 IEEE 60th
ISSN :
1090-3038
Print_ISBN :
0-7803-8521-7
Type :
conf
DOI :
10.1109/VETECF.2004.1400000
Filename :
1400000
Link To Document :
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