Title :
Transmit precoding scheme for inter-carrier interference suppression and path diversity in fractional sampling-orthogonal frequency division multiplexing (OFDM)
Author :
Nishimura, Hideki ; Inamori, Mamiko ; Ghavami, Morteza ; Sanada, Yukitoshi
Author_Institution :
Dept. of Electron. & Electr. Eng., Keio Univ., Kanagawa, Japan
Abstract :
Fractional sampling (FS) has been investigated to achieve path diversity with a single antenna in an OFDM system. However, in the FS-OFDM system, it is necessary to oversample a received signal and it leads to large power consumption in a small terminal. To shift the signal processing burdens for FS from a receiver to a transmitter, a precoded transmit path diversity scheme in OFDM has been proposed. It achieves path diversity without oversampling the received signal at the receiver side on time invariant channels. However, it has not taken time variant channels into consideration. On time variant channels, inter-carrier interference (ICI) deteriorates the bit-error-rate (BER) performance. In this study, the precoding for both ICI suppression and path diversity combining at the transmitter side has been proposed. Computer simulation shows that both the conventional scheme and the proposed scheme can achieve transmit path diversity. On a two path Rayleigh fading channel, the BER performance of the proposed scheme is better than that of the conventional scheme by about 1 dB. On ultra wideband (UWB) channels, the performance of the proposed scheme is 7-10 dB better at BER 10-2 than that of the conventional scheme. It can achieve ICI suppression and path diversity without any specific signal processing at the receiver. The effect of the ICI suppression is more significant as the number of the multipath is larger.
Keywords :
OFDM modulation; Rayleigh channels; error statistics; intercarrier interference; interference suppression; precoding; radio receivers; radio transmitters; signal processing; ultra wideband technology; BER; FS-OFDM system; Rayleigh fading channel; UWB channels; bit error rate; fractional sampling; intercarrier interference suppression; orthogonal frequency division multiplexing; path diversity; power consumption; radio receiver; radio transmitter; signal processing; time variant channels; transmit precoding scheme; ultra wideband channels;
Journal_Title :
Communications, IET
DOI :
10.1049/iet-com.2011.0366