Effects of cyclic prefix on OFDM systems over time-varying channels

Author

Yang, Lan ; Cheng, Shixing ; Wang, Haifeng

Author_Institution

Nat. Mobile Commun. Res. Lab., Southeast Univ., Nanjing

Volume

2

fYear

2005

fDate

11-14 Sept. 2005

Firstpage

750

Abstract

In this paper, effects of cyclic prefix (CP) are investigated for orthogonal frequency division multiplexing (OFDM) systems over time-varying channels. Although employing a CP as the guard interval is a simple way to combat the inter-symbol interference (ISI) and the inter-carrier interference (ICI), it reduces the transmission efficiency of the system, especially for channels with long channel-impulse response (CIR), such as hilly terrain channels. On the other hand, the time-varying channel also gives rise to ICI. We show that to achieve a signal-to-interference ratio of 20 dB, for slow fading channels, half the length of CIR is enough for CP. For fast fading channels, the Doppler frequency become domination factor to affect OFDM systems

Keywords

Doppler effect; OFDM modulation; fading channels; intersymbol interference; time-varying channels; transient response; CIR; Doppler frequency; ICI; ISI; OFDM system; channel-impulse response; cyclic prefix effects; fading channels; intercarrier interference; intersymbol interference; orthogonal frequency division multiplexing; time-varying channels; AWGN; Costs; Fading; Frequency domain analysis; Intersymbol interference; Mobile communication; OFDM; Performance analysis; Random variables; Time-varying channels; CP; ICI; ISI; OFDM;

fLanguage

English

Publisher

ieee

Conference_Titel

Personal, Indoor and Mobile Radio Communications, 2005. PIMRC 2005. IEEE 16th International Symposium on

Conference_Location

Berlin

Print_ISBN

9.7838007291e+012

Type

conf

DOI

10.1109/PIMRC.2005.1651543

Filename

1651543