The impact of FFT size on the performance of a combined OFDM-equalization radio modem

Author

Armour, Simon ; Nix, Andrew ; Bull, David

Author_Institution

Centre for Commun. Res., Bristol Univ., UK

Volume

3

fYear

1999

fDate

6/21/1905 12:00:00 AM

Firstpage

1506

Abstract

Conventional OFDM systems employ a guard interval to combat delay spread distortion of transmitted data. This reduces the efficiency of the OFDM transmission. A combined OFDM-equalization transmission strategy is presented in this paper. This strategy employs an adaptive equalizer to combat delay spread distortion instead of a guard interval. This facilitates the use of very short guard intervals and thus the efficiency of the OFDM transmission is improved. This paper presents the combined OFDM-equalization techique and demonstrates the efficiency improvement that it offers over conventional OFDM. The performance of the pre-FFT equalizer is sensitive to time variation of the mobile radio channel´s impulse response. Software simulation is employed to analyze this sensitivity and a relationship is determined between performance and FFT size. The results are considered in the context of application to existing and future mobile radio systems

Keywords

OFDM modulation; adaptive equalisers; delays; fast Fourier transforms; land mobile radio; modems; radio receivers; FFT size; OFDM transmission; adaptive equalizer; channel impulse response; combined OFDM-equalization radio modem; delay spread distortion; efficiency; guard intervals; mobile radio systems; performance; pre-FFT equalizer; sensitivity; time variation; Adaptive equalizers; Analytical models; Application software; Delay; Digital video broadcasting; Land mobile radio; Modems; OFDM modulation; Receivers; Robustness;

fLanguage

English

Publisher

ieee

Conference_Titel

Vehicular Technology Conference, 1999. VTC 1999 - Fall. IEEE VTS 50th

ISSN

1090-3038

Print_ISBN

0-7803-5435-4

Type

conf

DOI

10.1109/VETECF.1999.801545

Filename

801545