The impact of delay spread on multilevel FM systems in a Rayleigh fading, CCI and AWGN environment

Author

Wu, Gene K. ; Feher, Kamilo

Author_Institution

Dept. of Electr. & Comput. Eng., California Univ., Davis, CA, USA

fYear

1992

fDate

10-13 May 1992

Firstpage

528

Abstract

An experimental study of the impact of delay spread on the performance of 4 PAM-FM mobile systems in a Rayleigh fading, cochannel interference (CCI) and additive white Gaussian noise (AWGN) environment is presented. The increase of the modulation index can improve the BER if the reflected signal power is 10 dB less than the direct signal in the two-ray fading model. A strategy which reduces the impact of delay spread even in the worst case situation is proposed. By increasing the roll-off factor of the lowpass filters and by lowering the modulation index, for a BER of 0.01, the delay spread immunity is increased 300% without the need for adaptive equalization. In the delay spread environment, CCI is not significant if it is less than -20 dB. AWGN interference is noticeable only when it is higher than -13 dB

Keywords

delays; digital radio systems; fading; frequency modulation; mobile radio systems; pulse amplitude modulation; radiofrequency interference; white noise; 4 PAM-FM mobile systems; AWGN; BER; CCI; Rayleigh fading; additive white Gaussian noise; cochannel interference; delay spread; direct signal; lowpass filters; modulation index; reflected signal power; roll-off factor; two-ray fading model; AWGN; Adaptive filters; Additive white noise; Bit error rate; Delay; Interchannel interference; Modulation; Power system modeling; Radiofrequency interference; Rayleigh channels;

fLanguage

English

Publisher

ieee

Conference_Titel

Vehicular Technology Conference, 1992, IEEE 42nd

Conference_Location

Denver, CO

ISSN

1090-3038

Print_ISBN

0-7803-0673-2

Type

conf

DOI

10.1109/VETEC.1992.245340

Filename

245340